阅读说明：本技术 溅射方法 (Sputtering method ) 是由 泷旭 石桥哲 于 2019-02-27 设计创作，主要内容包括：本发明的溅射方法为使用反应性溅射装置的溅射方法,所述反应性溅射装置具备阴极装置,所述阴极装置朝向应形成于成膜对象物的化合物膜的形成区域排出溅射粒子,与所述形成区域相对的空间为相对区域,所述阴极装置具备：扫描部,用于在所述相对区域中扫描溅蚀区域；和靶,形成有所述溅蚀区域,并且扫描方向上的长度短于所述相对区域,所述扫描部在开始位置与结束位置之间朝向所述相对区域扫描所述溅蚀区域,所述开始位置为：相对于所述扫描方向上的所述形成区域的两个端部中的所述溅射粒子先到达的第一端部,所述扫描方向上的所述靶的表面的中点在所述扫描方向上位于所述形成区域的外侧的位置；所述结束位置为：相对于所述扫描方向上的所述形成区域的两个端部中的另一方的第二端部,所述扫描方向上的所述靶的所述表面的中点在所述扫描方向上位于所述形成区域的外侧的位置。所述溅射方法在使所述扫描部中的所述靶的速度从所述开始位置起加速至第二扫描速度之后,进一步加速至第二扫描速度,然后减速至第一扫描速度之后,扫描至所述结束位置,从所述第一扫描速度起加速并成为所述第二扫描速度的位置比所述第一端部更靠所述形成区域的内侧,从所述第二扫描速度起减速并成为所述第一扫描速度的位置比所述第二端部更靠所述形成区域的内侧。(A sputtering method according to the present invention is a sputtering method using a reactive sputtering apparatus including a cathode apparatus that discharges sputtering particles toward a formation region of a compound film to be formed on an object to be film-formed, a space facing the formation region being a facing region, the cathode apparatus including: a scanning section for scanning a sputtering region in the opposing region; and a target formed with the sputtering region and having a length in a scanning direction shorter than the opposing region, the scanning section scanning the sputtering region toward the opposing region between a start position and an end position, the start position being: a first end portion which is reached first by the sputtering particles in both end portions of the formation region in the scanning direction, and a midpoint of a surface of the target in the scanning direction is located at a position outside the formation region in the scanning direction; the end position is: a midpoint of the surface of the target in the scanning direction with respect to a second end portion of the other of the two end portions of the formation region in the scanning direction is located at a position outside the formation region in the scanning direction. The sputtering method includes accelerating the speed of the target in the scanning unit from the start position to a second scanning speed, then further accelerating the speed to the second scanning speed, then decelerating the speed to a first scanning speed, and then scanning the target to the end position, wherein the position where the target is accelerated from the first scanning speed and reaches the second scanning speed is located inside the formation region than the first end portion, and the position where the target is decelerated from the second scanning speed and reaches the first scanning speed is located inside the formation region than the second end portion.)

1. A sputtering method using a reactive sputtering apparatus,

the reactive sputtering apparatus includes a cathode device that discharges sputtering particles toward a region where a compound film to be formed on a film formation object is to be formed,

the space opposite to the formation region is an opposite region,

the cathode device is provided with:

a scanning section for scanning a sputtering region in the opposing region; and

a target formed with the sputtering region and having a length in a scanning direction shorter than the opposing region,

the scanning section scans the sputter area toward the opposite area between a start position and an end position, the start position being: a first end portion which is reached first by the sputtering particles in both end portions of the formation region in the scanning direction, and a midpoint of a surface of the target in the scanning direction is located at a position outside the formation region in the scanning direction; the end position is: a second end portion of the other of the two end portions of the formation region in the scanning direction, a midpoint of the surface of the target in the scanning direction being located at a position outside the formation region in the scanning direction,

the sputtering method includes accelerating the speed of the target in the scanning section from the start position to a first scanning speed, then further accelerating the speed to a second scanning speed, then decelerating the speed to the first scanning speed, and then scanning the target to the end position,

a position accelerated from the first scanning speed to the second scanning speed is located inside the formation region than the first end portion,

the position where the second scanning speed is decelerated from the second scanning speed to the first scanning speed is located inside the formation region than the second end portion.

2. The sputtering method according to claim 1,

a position accelerated from the start position to the first scanning speed is located outside the formation region than the first end portion,

the position where the speed is reduced from the first scanning speed to the end position is located outside the formation region than the second end portion.

3. The sputtering method according to claim 1,

a position accelerated from the start position to the first scanning speed is located inside the formation region than the first end portion,

the position where the speed is reduced from the first scanning speed to the end position is located further inside the formation region than the second end portion.

4. The sputtering method according to any one of claims 1 to 3,

the speed of the target in the scanning section is controlled to be symmetrical or asymmetrical with respect to the center of the formation region in the scanning direction.

5. The sputtering method according to claim 4,

the ratio of the first scanning speed to the second scanning speed is set within the range of 0.70 to 0.95.

6. The sputtering method according to claim 4,

the distance from the start position to the position at the second scanning speed in the scanning direction is set within a range of 200 to 400 mm.

7. The sputtering method according to claim 4,

the ratio of the distance from the start position to the position at the second scanning speed in the scanning direction to the distance between the first end of the formation region and the start position is set within a range of 1.3 to 2.7.

Technical Field

The present invention relates to a sputtering method, and more particularly to a technique suitable for reactive sputtering for forming a compound film on a large-sized substrate.

The present application claims priority based on patent application No. 2018-092341, filed in japan on 5, 11/2018, and the contents of which are incorporated herein by reference.

Background

A flat panel display such as a liquid crystal display or an organic EL display includes a plurality of thin film transistors for driving display elements. The thin film transistor has a channel layer, and a material forming the channel layer is, for example, an oxide semiconductor such as indium gallium zinc oxide (IGZO film). In recent years, the size of a substrate to be formed with a channel layer tends to increase, and the present applicant uses a target scanning sputtering apparatus as a sputtering apparatus for forming a film on a large substrate, thereby suppressing the occurrence of variations in the characteristics of a compound film, as described in patent document 1, for example.

In such a sputtering apparatus, when the target scans the substrate during film formation, the target is controlled to accelerate from a position outside the substrate profile, maintain a constant speed in the substrate plane, and decelerate toward the outside of the substrate profile. If the speed change is represented in the graph with the horizontal axis representing time and the vertical axis representing the cathode speed, the shape representing the speed change in the graph is substantially trapezoidal, and therefore this control is referred to as trapezoidal control.

Patent document 1: japanese patent No. 5801500

However, the trapezoidal control technique described above has a possibility that the uneven speed state of the cathode, that is, the characteristic distribution such as the film thickness in the vicinity of the edge portion of the substrate may vary, and there is a demand for improvement of the characteristic distribution variation.

Further, the film thickness becomes thick if the cathode is at a low speed, and becomes thin if the cathode is at a high speed. Therefore, the thickness of the film may be increased near the edge of the substrate as compared with the center of the substrate, and there is a demand for improving the increase in the thickness of the film near the edge of the substrate.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and aims to achieve the following object.

1. Suppress the variation of film forming characteristics.

2. The uniformity of the film thickness is improved.

3. Particularly, the variation of the film forming characteristics at the edge of the substrate is improved.

The sputtering method of the present invention is a sputtering method using a reactive sputtering apparatus. The reactive sputtering apparatus includes a cathode device that discharges sputtering particles toward a formation region of a compound film to be formed on an object to be film-formed, and a space facing the formation region is a facing region, and includes: a scanning section for scanning a sputtering region in the opposing region; and a target formed with the sputtering region and having a length in a scanning direction shorter than the opposing region, the scanning section scanning the sputtering region toward the opposing region between a start position and an end position, the start position being: a first end portion which is reached first by the sputtering particles in both end portions of the formation region in the scanning direction, and a midpoint of a surface of the target in the scanning direction is located at a position outside the formation region in the scanning direction; the end position is: a midpoint of the surface of the target in the scanning direction with respect to a second end portion of the other of the two end portions of the formation region in the scanning direction is located at a position outside the formation region in the scanning direction. The sputtering method includes accelerating the speed of the target in the scanning unit from the start position to a first scanning speed, then further accelerating the speed to a second scanning speed, then decelerating the speed to the first scanning speed, and then scanning the target to the end position, wherein the position where the target is accelerated from the first scanning speed and reaches the second scanning speed is located inside the formation region than the first end portion, and the position where the target is decelerated from the second scanning speed and reaches the first scanning speed is located inside the formation region than the second end portion.

In the sputtering method according to the present invention, the position accelerated from the start position to the first scanning speed may be located outside the formation region than the first end portion, and the position decelerated from the first scanning speed to the end position may be located outside the formation region than the second end portion. In the sputtering method according to the present invention, the position accelerated from the start position to the first scanning speed may be located inside the formation region than the first end portion, and the position decelerated from the first scanning speed to the end position may be located inside the formation region than the second end portion.

In the present invention, it is more preferable that the speed of the target in the scanning section is controlled to be symmetrical or asymmetrical with respect to the center of the formation region in the scanning direction.

In the present invention, a ratio of the first scanning speed to the second scanning speed may be set in a range of 0.70 to 0.95.

In the present invention, a distance from the start position to a position at the second scanning speed in the scanning direction may be set to be in a range of 200 to 400 mm.

Further, a ratio of a distance from the start position to a position at the second scanning speed in the scanning direction to a distance between the first end of the formation region and the start position may be set within a range of 1.3 to 2.7.

A sputtering method according to the present invention is a sputtering method using a reactive sputtering apparatus including a cathode apparatus that discharges sputtering particles toward a formation region of a compound film to be formed on an object to be film-formed, a space facing the formation region being a facing region, the cathode apparatus including: a scanning section for scanning a sputtering region in the opposing region; and a target formed with the sputtering region and having a length in a scanning direction shorter than the opposing region, the scanning section scanning the sputtering region toward the opposing region between a start position and an end position, the start position being: a first end portion which is reached first by the sputtering particles in both end portions of the formation region in the scanning direction, and a midpoint of a surface of the target in the scanning direction is located at a position outside the formation region in the scanning direction; the end position is: with respect to a second end portion of the other of the two end portions of the formation region in the scanning direction, a midpoint of the surface of the target in the scanning direction is located at a position outside the formation region in the scanning direction, the velocity of the target in the scanning portion is accelerated from the start position to a first scanning velocity, then is further accelerated to a second scanning velocity, then is decelerated to a first scanning velocity, and then is scanned to the end position, the position accelerated from the first scanning velocity and changed to the second scanning velocity is located further inside the formation region than the first end portion, and the position decelerated from the second scanning velocity and changed to the first scanning velocity is located further inside the formation region than the second end portion, whereby a film thickness of a substrate end portion in the scanning direction corresponding to an end portion of the formation region can be reduced to be thicker than a film thickness of a substrate center portion, and prevents the generation of variations in film characteristics.

In the sputtering method according to the present invention, since the position accelerated from the start position to the first scanning speed is located outside the formation region than the first end portion and the position decelerated from the first scanning speed to the end position is located outside the formation region than the second end portion, it is possible to reduce the thickness of the substrate end portion in the scanning direction corresponding to the end portion of the formation region from being thicker than the thickness of the substrate center portion and prevent the occurrence of variations in film characteristics.

In the sputtering method according to the present invention, since the position accelerated from the start position to the first scanning speed is located inside the formation region than the first end portion and the position decelerated from the first scanning speed to the end position is located inside the formation region than the second end portion, it is possible to reduce the thickness of the substrate end portion in the scanning direction corresponding to the end portion of the formation region from being thicker than the thickness of the substrate center portion and prevent the occurrence of variations in film characteristics.

In the present invention, by controlling the speed of the target in the scanning unit to be symmetrical or asymmetrical with respect to the center of the formation region in the scanning direction, film formation can be performed symmetrically with respect to the center of the substrate in the scanning direction corresponding to the formation region, and film formation can be performed so that film characteristics such as film thickness are uniform over the entire length of the substrate in the scanning direction corresponding to the formation region.

In the present invention, since the ratio of the first scanning speed to the second scanning speed is set in the range of 0.70 to 0.95, it is possible to prevent the film thickness at the end portion from being larger than the film thickness at the center of the substrate in the scanning direction corresponding to the formation region.

In the present invention, since the distance from the start position to the position at the second scanning speed in the scanning direction is set to be in the range of 200 to 400mm, the film thickness can be made uniform in the substrate in the scanning direction corresponding to the formation region, and variations in film thickness can be reduced.

Further, since the ratio of the distance from the start position to the position at the second scanning speed in the scanning direction to the distance in the scanning direction between the first end of the formation region and the start position is set to be in the range of 1.3 to 2.7, the film thickness can be made uniform in the substrate in the scanning direction corresponding to the formation region, and variations in film thickness can be reduced.

According to the present invention, the following effects can be obtained: that is, variation in film formation characteristics can be suppressed, uniformity of film thickness can be improved, and variation in film formation characteristics at the edge portion of the substrate can be improved.

Drawings

Fig. 1 is a configuration diagram showing the overall configuration of a sputtering apparatus in a sputtering method according to a first embodiment of the present invention.

Fig. 2 is a schematic diagram showing the structure of a sputtering chamber in the sputtering method according to the first embodiment of the present invention.

Fig. 3 is a schematic diagram showing the structure of a cathode unit in the sputtering method according to the first embodiment of the present invention.

Fig. 4 is a diagram for explaining a sputtering action in the sputtering method according to the first embodiment of the present invention.

Fig. 5 is a graph showing a relationship between a scanning direction distance and a scanning speed in the sputtering method according to the first embodiment of the present invention.

Fig. 6 is a diagram for explaining a sputtering action in the sputtering method according to the first embodiment of the present invention.

Fig. 7 is a diagram for explaining a sputtering action in the sputtering method according to the first embodiment of the present invention.

Fig. 8 is a structural diagram schematically showing the structure of a cathode unit in the sputtering method according to the second embodiment of the present invention.

Fig. 9 is a schematic diagram showing the structure of a sputtering chamber in a sputtering method according to a third embodiment of the present invention.

Fig. 10 is a diagram for explaining a sputtering action in the sputtering method according to the third embodiment of the present invention.

Fig. 11 is a diagram for explaining a sputtering action in the sputtering method according to the third embodiment of the present invention.

Fig. 12 is a schematic diagram schematically showing the structure of a sputtering chamber in a modification.

Fig. 13 is a schematic diagram schematically showing the structure of a cathode unit in a modification.

Fig. 14 is a schematic diagram schematically showing the configuration of a sputtering apparatus according to a modification.

Fig. 15 is a diagram showing a relationship between a scanning direction distance and a scanning speed in the sputtering method according to the embodiment of the present invention.

Fig. 16 is a graph showing film thicknesses in the sputtering method according to the embodiment of the present invention.

Fig. 17 is a graph showing a relationship between a scanning direction distance and a scanning speed in the sputtering method according to the embodiment of the present invention.

Fig. 18 is a graph showing film thicknesses in the sputtering method according to the embodiment of the present invention.

Fig. 19 is a graph showing a relationship between a scanning direction distance and a scanning speed in the sputtering method according to the embodiment of the present invention.

Detailed Description

Next, a sputtering method according to a first embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a structural diagram showing the overall configuration of a sputtering apparatus (reactive sputtering apparatus) in the sputtering method according to the present embodiment. Fig. 2 is a schematic diagram showing the structure of the sputtering chamber according to the present embodiment. Fig. 3 is a structural diagram schematically showing the structure of the cathode unit of the present embodiment. Fig. 4 and 6 to 8 are diagrams for explaining the sputtering operation in the present embodiment. In fig. 1, reference numeral 10 denotes a sputtering apparatus.

As an example of the sputtering apparatus 10 of the present embodiment, a case will be described in which the compound film formed on the substrate is an indium gallium zinc oxide film (IGZO film). The overall structure of the sputtering apparatus, the structure of the sputtering chamber, the structure of the cathode unit, and the operation of the sputtering chamber will be described in order below.

[ Overall Structure of sputtering apparatus ]

As shown in fig. 1, the sputtering apparatus 10 of the present embodiment includes a carry-in chamber 11, a pretreatment chamber 12, and a sputtering chamber 13 arranged in a one-directional conveyance direction. Each of the three chambers is linked to other chambers adjacent to each other by a gate valve 14. An exhaust unit 15 for exhausting gas and the like in the chamber is connected to each of the three chambers, and each of the three chambers is independently depressurized by driving of the exhaust unit 15. A film forming passage 16 and a recovery passage 17, which are two passages extending in the conveying direction and parallel to each other, are laid on the respective bottom surfaces of the three chambers.

The film formation path 16 and the recovery path 17 are configured by, for example, a guide rail extending in the conveyance direction, a plurality of rollers arranged in the conveyance direction, a plurality of motors for rotating each of the plurality of rollers, and the like. The film formation path 16 conveys the tray T carried into the sputtering apparatus 10 from the carry-in/out chamber 11 toward the sputtering chamber 13. The recovery duct 17 conveys the tray T carried into the sputtering chamber 13 from the sputtering chamber 13 toward the carry-out and carry-in chamber 11.

A rectangular substrate S extending in front of the paper surface is fixed to the tray T in an upright state. The width of the substrate S is 2200mm in the transport direction and 2500mm in front of the paper surface, for example.

The carry-in-and-out chamber 11 carries the substrate S before film formation carried in from the outside of the sputtering apparatus 10 to the pre-processing chamber 12, and carries out the substrate S after film formation carried in from the pre-processing chamber 12 to the outside of the sputtering apparatus 10. When the substrate S before film formation is carried into the carry-in-and-out chamber 11 from the outside, and when the substrate S after film formation is carried out from the carry-in-and-out chamber 11 to the outside, the inside of the carry-in-and-out chamber 11 is pressurized to the atmospheric pressure. When the substrate S before film formation is carried into the pre-processing chamber 12 from the carry-in and carry-out chamber 11, and when the substrate S after film formation is carried out from the pre-processing chamber 12 to the carry-in and carry-out chamber 11, the interior of the carry-in and carry-out chamber 11 is depressurized to the same degree as the interior of the pre-processing chamber 12.

The pretreatment chamber 12 performs a process necessary for film formation, such as a heating process or a cleaning process, on the substrate S before film formation which is carried into the pretreatment chamber 12 from the carry-in/out chamber 11.

The pretreatment chamber 12 carries the substrate S carried out from the carry-in/out chamber 11 to the pretreatment chamber 12 into the sputtering chamber 13. The pretreatment chamber 12 carries out the substrate S carried out from the sputtering chamber 13 to the pretreatment chamber 12 to the carry-in and carry-out chamber 11.

The sputtering chamber 13 includes a cathode device 18 for discharging sputtered particles toward the substrate S, and a channel changing unit 19 disposed between the film forming channel 16 and the recovery channel 17. The sputtering chamber 13 forms an IGZO film on the substrate S before film formation, which is carried from the pretreatment apparatus 12 to the sputtering chamber 13, by using the cathode apparatus 18. The sputtering chamber 13 moves the tray T after film formation from the film formation path 16 to the recovery path 17 by using the path changing section 19.

[ Structure of sputtering Chamber ]

As shown in fig. 2, the film formation path 16 of the sputtering chamber 13 conveys the substrate S carried into the sputtering chamber 13 from the pre-processing chamber 12 in the conveyance direction, and the position of the tray T is fixed in the middle of the film formation path 16 while the thin film formation on the substrate S is started and ended. When the position of the tray T is fixed by the supporting member for supporting the tray T, the edge position in the conveying direction in the substrate S is also fixed.

The gas supply unit 21 of the sputtering chamber 13 supplies a gas used for sputtering to a gap between the tray T and the cathode device 18. The gas supplied from the gas supply unit 21 contains a sputtering gas such as argon and a reaction gas such as oxygen.

The cathode arrangement 18 has a cathode unit 22, the cathode unit 22 being disposed along a plane opposite to the surface Sa of the substrate S. In the cathode unit 22, a target 23, a backing plate 24, and a magnetic circuit 25 are arranged in this order from a position close to the substrate S.

The target 23 is formed in a flat plate shape along a plane facing the substrate S, and has a width longer than the substrate S in a height direction which is a direction orthogonal to the paper surface. The width of the substrate S in the transport direction is smaller than the width of the substrate S, for example, about one fifth of the width of the substrate S. The main component of the material forming the target 23 is IGZO, and for example, 95% by mass of the material forming the target 23 is IGZO, and preferably 99% by mass or more is IGZO.

The backing plate 24 is formed in a flat plate shape along a plane opposed to the substrate S, and the backing plate 24 is bonded to a surface of the target 23 not facing the substrate S. A dc power supply 26D is connected to the back plate 24. The direct-current power supplied by the direct-current power supply 26D is supplied into the target 23 via the backing plate 24.

The magnetic circuit 25 is composed of a plurality of magnetic bodies having magnetic poles different from each other, and forms a magnetron magnetic field on the surface 23a of the target 23 and the side surface of the target 23 facing the substrate S, when the direction along the normal line of the surface 23a of the target 23 is the normal line direction, the density of plasma generated in the gap between the surface 23a of the target 23 and the surface Sa of the substrate S is highest at a portion where the magnetic field component along the normal line direction in the magnetron magnetic field formed by the magnetic circuit 25 is 0(B ⊥ 0), and in the following description, a region where the magnetic field component along the normal line direction in the magnetron magnetic field formed by the magnetic circuit 25 is 0 is a region where the plasma density is high.

The cathode device 18 includes a scanning unit 27 for moving the cathode unit 22 in a scanning direction in one direction. The scanning direction is a direction parallel to the conveying direction. The scanning unit 27 is configured by, for example, a guide rail extending in the scanning direction, rollers attached to each of both end portions in the height direction in the cathode unit 22, a plurality of motors for rotating the respective rollers, and the like. The guide rail of the scanning section 27 has a longer width in the scanning direction than the substrate S. The scanning unit 27 may be embodied in other configurations as long as it can move the cathode unit 22 in the scanning direction.

The scanning section 27 scans the cathode unit 22 in the facing space R2, which is a space facing the IGZO film formation region R1, by moving the cathode unit 22 in the scanning direction. The entire surface Sa of the substrate S, which is an example of the object to be film-formed, is an example of the formation region R1 of the IGZO film. When the cathode device 18 discharges the sputtered particles and starts forming the IGZO film, the scanner section 27 moves the cathode unit 22 in the scanning direction from, for example, a start position St, which is one end portion in the scanning direction in the scanner section 27, toward an end position En, which is the other end portion in the scanning direction. Thereby, the scanning section 27 scans the target 23 of the cathode unit 22 in the facing region R2 opposite to the formation region R1.

The direction in which the formation region R1 and the opposing region R2 oppose each other is an opposing direction. The distance in the opposing direction between the surface Sa of the substrate S and the surface 23a of the target 23 is 300mm or less, for example, 150 mm.

When the cathode unit 22 is disposed at the start position St, a distance D1 in the scanning direction between the first end Re, to which sputtered particles in the two ends of the formation region R1 in the scanning direction first reach, and the first end 23e1 of the target 23 that is close to the first end Re1 in the scanning direction is 150mm or more.

When the cathode unit 22 is disposed at the start position St, the distance D2 in the scanning direction between the midpoint 23e3 (center position) of the target 23 and the first end Re1 is 100mm to 300 mm.

When the cathode unit 22 is located at the end position En, a distance D1 in the scanning direction between the second end portion Re2, which the sputtered particles in both end portions of the formation region R1 reach after reaching, and the second end portion 23e2 of the target 23 close to the second end portion Re2 in the scanning direction is 150mm or more.

When the cathode unit 22 is disposed at the end position En, the distance D2 in the scanning direction between the midpoint 23e3 (center position) of the target 23 and the second end Re2 is 100mm to 300 mm.

These distance D1 and distance D2 may be set to be symmetrical with respect to the center of the substrate S in the scanning direction, i.e., these distances D1, D2 may be set to be equal.

Further, when the IGZO film is formed in the formation region R1, the scanning section 27 may also scan the cathode unit 22 once in the scanning direction from the start position St toward the end position En. Alternatively, the scanner 27 may scan the cathode unit 22 in the scanning direction from the start position St toward the end position En, and then scan the cathode unit 22 in the scanning direction from the end position En toward the start position St. Thereby, the scanning section 27 scans the cathode unit 22 twice in the scanning direction. The scanning section 27 may also scan the cathode unit 22 between the start position St and the end position En a plurality of times by moving the cathode unit 22 alternately in the scanning direction between the start position St and the end position En. The number of times the scanning unit 27 scans the cathode unit 22 is changed according to the thickness of the IGZO film. If the conditions other than the number of times of scanning of the cathode unit 22 are the same, the thicker the thickness of the IGZO film, the larger the number of times the scanning section 27 scans the cathode unit 22 is set to.

[ Structure of cathode Unit ]

Next, the structure of the cathode unit 22 will be described in more detail. Fig. 3 shows a state in which the cathode unit 22 is disposed at the start position St described in fig. 2.

As shown in fig. 3, a plane on which the front surface Sa of the substrate S is disposed is a virtual plane Pid, and a straight line orthogonal to the virtual plane Pid is a normal line Lv. The surface 23a of the target 23, which is the side surface facing the substrate S, is arranged on one plane parallel to the virtual plane Pid.

The magnetic circuit 25 for forming the magnetron field B on the surface 23a of the target 23 forms two perpendicular magnetic field zero regions having a magnetic field component of 0(B ⊥ 0) along the normal line Lv on the surface 23a of the target 23 in the surface 23a of the target 23, the sputtered particles SP. are mainly discharged from the two perpendicular magnetic field zero regions, the perpendicular magnetic field zero region near the first end Re1 of the formation region R1 in the scanning direction is a first sputtering region E1, and the perpendicular magnetic field zero region far from the first end Re1 is a second sputtering region E2.

The magnetic circuit 25 has a width substantially equal to that of the target 23 in the height direction perpendicular to the paper surface, and has a width of, for example, about one third of that of the target 23 in the scanning direction.

The cathode unit 22 includes two shield plates 28a and 28b, and the two shield plates 28a and 28b prevent a part of the plurality of sputtering particles SP discharged from the first sputtering region E1 and the second sputtering region E2 from reaching the substrate S. The two shield plates 28a and 28b have a width substantially equal to that of the target 23 in the height direction, and protrude from the surface 23a of the target 23 toward the virtual plane Pid in the width direction orthogonal to the scanning direction. The projecting widths of the first shield plate 28a and the second shield plate 28b in the width direction are equal to each other. The first shielding plate 28a is an example of a first shielding portion, and the second shielding plate 28b is an example of a second shielding portion.

When the cathode unit 22 is disposed at the start position St, the first shield plate 28a as one shield plate is disposed between the first end portion Re1, which the sputtered particles SP in the formation region R1 reach first, and the first end portion 23e1 of the target 23 close to the first end portion Re1 in the scanning direction. When the cathode unit 22 is located at the start position St, the second shielding plate 28b as the other shielding plate is disposed at a position farther from the formation region R1 than the second end portion 23e2 in the scanning direction, and the second end portion 23e2 is the end of the target 23 farther from the first end portion Re1 of the formation region R1.

The cathode unit 22 includes a magnetic path scanning unit 29 for changing the position of the magnetic path 25 with respect to the target 23. The magnetic circuit scanning unit 29 is configured by, for example, a guide rail extending in the scanning direction, rollers attached to each of both end portions in the height direction of the magnetic circuit 25, and a plurality of motors for rotating the respective rollers. The guide rail of the magnetic circuit scanning unit 29 has a width substantially equal to the width of the target 23 in the scanning direction. The magnetic path scanning unit 29 may be embodied in other configurations as long as it can move the magnetic path 25 in the scanning direction.

The magnetic circuit scanning section 29 scans the magnetic circuit 25 between a first position P1 where the first end 23e1 of the target 23 and the magnetic circuit 25 overlap and a second position P2 where the second end 23e2 of the target 23 and the magnetic circuit 25 overlap in the scanning direction. When the cathode device 18 discharges the sputtered particles SP and starts forming the IGZO film, the magnetic path scanning section 29 moves the magnetic path 25 from the first position P1 toward the second position P2. When the scanning section 27 moves the cathode unit 22 from the start position Wt toward the end position En, the magnetic circuit scanning section 29 moves the magnetic circuit 25 from the first position P1 toward the second position P2, for example. That is, when the cathode unit 22 starts to move from the start position St toward the end position En, the magnetic circuit 25 starts to move from the first position P1 toward the second position P2, and when the cathode unit 22 reaches the end position En, the magnetic circuit 25 reaches the second position P2. In this way, the magnetic path scanning unit 29 moves the magnetic path 25 in the scanning direction in the direction opposite to the moving direction of the cathode unit 22.

When the scanning section 27 scans the cathode unit 22 from the start position St toward the end position En and passes the target 23 through the one-time opposing region R2, it is preferable that the magnetic circuit scanning section 29 scans the magnetic circuit 25 once from the first position P1 toward the second position P2.

If the magnetic circuit 25 makes a plurality of times back and forth between the first position P1 and the second position P2 while the target 23 passes through the opposing region R2 once and the IGZO film is formed, the relative speed of the magnetic circuit 25 with respect to the target 23 changes every time the scanning direction of the magnetic circuit 25 changes with respect to the scanning direction of the target 23. If the relative speed of the magnetic circuit 25 changes, the state of the plasma formed on the surface of the target 23 also changes, and therefore the number of sputtering particles SP discharged toward the formation region R1 also changes. As a result, the IGZO film varies in thickness in the scanning direction of the target 23.

Therefore, when the scanning unit 27 passes the target 23 through the primary opposing region R2, the magnetic circuit scanning unit 29 scans the primary magnetic circuit 25 from the first position P1 toward the second position P2, thereby suppressing the variation in the thickness of the IGZO film in the scanning direction.

When the magnetic circuit scanning unit 29 moves the magnetic circuit 25 in the scanning direction, the vertical magnetic field zero region formed by the magnetic circuit 25 also moves in the scanning direction. Therefore, the first sputtering region E1 and the second sputtering region E2 also move on the surface 23a of the target 23 in the scanning direction. In addition, when the scanning unit 27 scans the cathode unit 22 in the facing region R2 in the scanning direction, the scanning unit 27 also scans the first sputter region E1 and the second sputter region E2 in the facing region R2.

[ function of sputtering Chamber ]

Next, the operation of the sputtering target 13 will be described. Hereinafter, an operation of the cathode unit 22 moving in the scanning direction from the start position St to the end position En will be described as an example of the operation of the sputtering chamber with reference to fig. 4.

When the cathode device 18 starts to discharge the sputtered particles SP toward the IGZO film formation region R1, the cathode unit 22 is disposed at the start position St as shown in fig. 4. At this time, a distance D1 between the first end Re1, which the sputtered particles SP in the two ends of the formation region R1 in the scanning direction reach first, and the first end 23e1, which is close to the formation region R1, in the two ends of the target 23 in the scanning direction is 150mm or more. Therefore, when the dc power is supplied to the target 23, most of the sputtering particles SP discharged from the target 23 hardly reach the substrate S.

In addition, when the cathode device 18 starts to discharge the sputtered particles SP toward the IGZO film formation region R1, the midpoint 23e3 (center position) of the target 23 in the scanning direction starts to accelerate from the start position St that is the outer side of the first end portion Re1 in the scanning direction.

Here, the energy, the oxygen species, the reaction probability, and the like of the sputtering particles SP discharged from the target 23 when the dc power is supplied are different from those of the sputtering particles SP discharged from the target 23 at a predetermined timing when the dc power is continuously supplied. Therefore, if the sputtering particles SP reach the substrate S when the dc power is supplied, an IGZO film having a different film quality from the portion formed by the sputtering particles SP reaching the substrate S is formed thereafter. As a result, the composition of the film varies in the molecular layer at the initial stage of formation of the IGZO film.

In this regard, the midpoint 23e3 (center position) of the target 23 is accelerated from the start position St outside the first end Re in the scanning direction, thereby preventing the film thickness from becoming unnecessarily thick in the molecular layer at the initial stage of formation of the IGZO film and suppressing the occurrence of variations in the composition of the film.

Further, since the distance D1 in the scanning direction between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 is 150mm or more, the composition of the film is suppressed from being deviated in the molecular layer at the initial stage of formation of the IGZO film.

And, if the cathode unit 22 moves in the scanning direction, the sputtering particles SP that are discharged in the direction from the first sputtering region E1 toward the cathode unit 22 among the sputtering particles SP discharged from the target 23 first reach the substrate S.

At this time, the scanning speed at which the cathode unit 22 moves in the scanning direction is set as follows.

Fig. 5 is a graph showing a relationship between the scanning direction distance and the scanning speed in the present embodiment.

In the present embodiment, as shown in fig. 5, the speed of the cathode unit 22 is accelerated until the midpoint 23e3 (center position) of the target 23 reaches the first acceleration position AP1 from the start position St, and becomes the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2 from the first acceleration position AP1, the cathode unit 22 moves at a constant speed at the first scanning speed V1. And, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the cathode unit 22 is accelerated to the second scanning speed V2.

Until the midpoint 23e3 (center position) of the target 23 reaches the second deceleration position BP2 from the second acceleration position AP2, the cathode unit 22 moves at a constant speed at the second scanning speed V2.

Then, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second deceleration position BP2, the cathode unit 22 is decelerated to the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the first deceleration position BP1 from the second deceleration position BP2, the cathode unit 22 moves at a uniform speed at the first scanning speed V1. Finally, the scanning is terminated by decelerating and stopping until the midpoint 23e3 (center position) of the target 23 reaches the end position En from the first deceleration position BP 1.

Here, as shown in fig. 5, the first acceleration position AP1 may be set to an outside position of the first end Re in the scanning direction.

The first scanning speed V1 can be appropriately set for the film thickness of the IGZO film required for the edge portion of the substrate S. The first scanning speed V1 may be set within a range of 0.70 to 0.95 relative to the second scanning speed V2.

The speed of the cathode unit 22 is set to the first scanning speed V1 at a constant speed from the first acceleration position AP1 to the second acceleration position AP 2. Further, the speed of the cathode unit 22 is set to be accelerated from the start position St to the first acceleration position AP 1.

Further, as shown in fig. 5, the second acceleration position AP2 may be set between an outer position of the first end Re1 in the scanning direction and an inner position of the first end Re1 in the scanning direction.

Specifically, the second acceleration position AP2 may be set within a range of 200 to 400mm from the midpoint 23e3 (center position) of the target 23 at the start position St.

That is, the ratio of the distance between the midpoint 23e3 (center position) of the target 23 at the start position St and the second acceleration position AP2 to the distance between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 near the first end Re1 at the start position St may be set in the range of 1.3 to 2.7(200/150 to 400/150).

Further, if the second scanning speed V2 is increased, the film thickness of the formed IGZO film is increased, and if the second scanning speed V2 is decreased, the film thickness of the formed IGZO film is increased. Therefore, the second scanning speed V2 can be appropriately set according to the film thickness of the IGZO film required for the substrate S.

From the second acceleration position AP2 to the second deceleration position BP2, the speed of the cathode unit 22 is set to be uniform at the second scanning speed V2.

As shown in fig. 5, the second deceleration position BP2 may be set between an outer position of the second end Re2 in the scanning direction and an inner position of the second end Re2 in the scanning direction.

In addition, the second deceleration position BP2 may be set to a position symmetrical to the center of the substrate S in the scanning direction with respect to the second acceleration position AP 2.

Here, as shown in fig. 5, the first deceleration position BP1 may be set to an outer position of the second end Re2 in the scanning direction. The first deceleration position BP1 may be set to a position symmetrical to the center of the substrate S in the scanning direction with respect to the first acceleration position AP 1.

From the second deceleration position BP2 to the first deceleration position BP1, the speed of the cathode unit 22 is positioned at a constant speed at the first scanning speed V1.

Further, the start position St and the end position En may be set to positions symmetrical to the center of the substrate S in the scanning direction.

The speed of the cathode unit 22 is set to be equally decelerated (equally accelerated) from the first deceleration position BP1 to the end position En.

In this way, by setting the distance between the first acceleration position AP1 and the second acceleration position AP2, the film thickness of the IGZO film can be prevented from increasing at the edge portion of the substrate S. Meanwhile, by setting the ratio of the first scanning speed V1 to the second scanning speed V2, the film thickness of the IGZO film can be prevented from varying at the center of the substrate S.

The angle formed by the plane of the flight path F and the virtual plane Pid, i.e., the surface Sa of the substrate S, of the sputtered particles SP discharged from each sputtering region, which is a vertical magnetic field zero region, is the incident angle θ of the sputtered particles.

The shield plates 28a and 28b prevent the sputtering particles SP whose incident angle θ is included in a predetermined range among the plurality of sputtering particles SP discharged from the sputtering regions E1 and E2 from reaching the surface Sa of the substrate S as the formation region R1. Although the first shield plate 28a and the second shield plate 28b are disposed at different positions in the scanning direction, the configuration related to the limitation of the sputtered particles Sp that reach the substrate S is common. Therefore, the first shield plate 28a will be described in detail below, and the second shield plate 28b will not be described.

When the magnetic circuit 25 is arranged at the first position P1, the distance in the scanning direction between the first sputtering region E1 and the first shield plate 28a is smallest. Therefore, of the plurality of sputtering particles SP discharged from the first sputtering region E1 in the direction toward the cathode unit 22, the range of the incident angle θ 1 of the sputtering particles SP that collide with the first shielding plate 28a is largest. The first shield plate 28a does not allow the sputtering particles SP having an incident angle θ 1 of, for example, 60 ° or less among the plurality of sputtering particles SP discharged from the first sputtering region E1 toward the cathode unit 22 to reach the substrate S.

On the other hand, when the magnetic circuit 25 is disposed at the second position P2, the distance between the first sputtering region E1 and the first shield plate 28a in the scanning direction is maximized. Therefore, of the plurality of sputtering particles SP discharged from the first sputtering region E1 in the direction toward the cathode unit 22, the range of the incidence angle θ 2 of the sputtering particles SP that collide with the first shielding plate 28a is the smallest. The first shield plate 28a does not allow the sputtering particles SP having the incident angle θ 2 of 30 ° or less among the plurality of sputtering particles SP discharged from the first sputtering region E1 toward the cathode unit 22 to reach the substrate S.

That is, regardless of the position of the magnetic circuit 25 in the scanning direction, the first shield plate 28a does not allow the sputtering particles SP having the incident angle θ of 30 ° or less among the sputtering particles SP discharged from the first sputtering region E1 toward the cathode unit 22 to reach the substrate S.

Here, among the sputtered particles SP discharged from the first sputtering region E1, a plurality of sputtered particles SP discharged in the direction of the cathode cell 22 do not fly toward the second sputtering region E2 adjacent to the first sputtering region E1, and therefore, the flight path F does not pass through the B ⊥ 0 region extending in the height direction from the space where the other sputtered particles fly toward the sputtered particles from the other sputtering region, and therefore, the probability of the sputtered particles SP reacting with the active species of oxygen contained in the plasma is reduced, and the oxygen density per unit thickness or unit area of the IGZO film formed of the sputtered particles SP is reduced.

On the other hand, the smaller the incident angle θ of the sputtered particles SP, the larger the flight distance until the sputtered particles SP reach the substrate S after crossing the B ⊥ 0 region, which is a region with high plasma density, the larger the number of times the sputtered particles SP collide with particles other than the active species such as the sputtering gas in the space crossing the B ⊥ 0 region, which is a region with high plasma density.

In this regard, since the first shielding plate 28a does not allow the sputtered particles SP having an incident angle θ of 30 ° or less to reach the substrate S, it is difficult to form an IGZO film having a small oxygen content or film density. As a result, variations in the composition and film density per unit thickness and unit area of the IGZO film are suppressed.

On the other hand, when the cathode unit 22 moves in the scanning direction from the end position En toward the start position St, the second shield plate 28b does not allow the sputtered particles SP having an incident angle θ of 30 ° or less among the plurality of sputtered particles SP discharged from the second sputtering region E2 toward the cathode unit 22 to reach the substrate S. Therefore, the variation in composition or film density per unit thickness or unit area of the IGZO film is suppressed.

The cathode unit 22 is disposed at the start position St, and as shown in fig. 4, when the cathode device 18 starts to discharge the sputtered particles SP toward the IGZO film formation region R1, the magnetic circuit 25 is disposed at the first position P1. At this time, a distance D1 between the first end Re1, which the sputtered particles SP reach first, of the two ends of the formation region R1 in the scanning direction and the first end 23e1, which is close to the formation region R1, of the two ends of the target 23 in the scanning direction is 150mm or more. Therefore, regardless of the incident angle θ of the sputtering particles SP, most of the sputtering particles SP discharged from the target 23 when the dc power is supplied to the target 23 hardly reach the substrate S.

If the cathode unit 22 is moved in the scanning direction, the sputtering particles SP that are first discharged from the target 23 and reach the substrate S are restricted to sputtering particles SP having an incident angle θ smaller than 30 ° by the first shield plate 28 a.

Further, since the first sputtering region E1 is smaller in distance from the formation region R1 than the second sputtering region E2, the probability that the sputtering particles SP that first reach each portion of the substrate S are the sputtering particles SP discharged from the first sputtering region E1 is high. Therefore, the probability that the initial layer of the IGZO film is the sputtered particles SP that are discharged from the first sputtering region E1 toward the cathode unit 22 and have an incident angle θ greater than 30 ° is high. Therefore, the composition of the film is suppressed from being deviated in the initial layer of the IGZO film.

When the IGZO film starts to be formed, the magnetic path scanning unit 29 arranges the magnetic path 25 at the first position P1. Therefore, compared to the case where the magnetic circuit 25 is disposed at another position between the first position P1 and the second position P2, the distance in the scanning direction between the first sputtering region E1 formed by the magnetic circuit 25 and the first shield plate 28a is the smallest. Therefore, the range of the incidence angle θ of the sputtering particles SP that collide with the first shield plate 28a is largest, and the sputtering particles SP having a larger incidence angle θ reach the vicinity of the first end Re1 of the formation region R1, compared to the case where the magnetic circuit 25 is disposed at another position. As a result, the variation in the composition of the IGZO film is further suppressed.

As shown in fig. 6, when the cathode unit 22 scans the facing region R2 facing the formation region R1, the sputtering particles SP having an incident angle θ of 30 ° or less among the sputtering particles SP discharged from the first sputtering region E1 in the direction toward the cathode unit 22 do not reach the substrate S. Also, of the sputtering particles SP discharged in the direction opposite to the direction from the second sputtering region E2 toward the cathode unit 22, the sputtering particles SP having an incident angle of 30 ° or less do not reach the substrate S due to the second shield plate 28 b.

Thus, the sputtering particles SP which are discharged from the first sputtering region E1 and reach the substrate S after the sputtering particles SP which reach the substrate S first are also not limited to the sputtering particles SP having the incident angle θ larger than 30 °. As a result, the IGZO film is formed only by the sputtered particles SP whose incident angle θ is limited, and therefore variation in composition per unit thickness or unit area is suppressed in the entire thickness direction of the IGZO film.

As shown in fig. 7, when the cathode unit 22 is disposed at the end position En, the distance D1 between the second end Re2, to which the particles SP are sputtered, and the second end 23e2 of the target 23, of the two ends of the formation region R1 in the scanning direction, is 150mm or more in the scanning direction. Therefore, when the cathode unit 22 scans from the end position En toward the start position St, the scanning of the cathode unit 22 is started in a state where most of the sputtering particles SP discharged from the target 23 do not reach the substrate S. Therefore, the sputtered particles reaching the second end 23e2 of the formation region R1 are suppressed from being different from other portions in the formation region R1. As a result, the composition of the IGZO film is prevented from being deviated in the scanning direction.

Further, in the state where the cathode unit 22 is disposed at the end position En, the supply of the dc power to the target 23 is stopped, and in the state where the cathode unit 22 is disposed at the end position, even if the supply of the dc power is restarted, the sputtering particles SP at the time of returning the dc power hardly reach the substrate S. Therefore, the composition of the IGZO film per unit thickness or unit area is prevented from being varied.

In this embodiment, since the distance D1 between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 is 150mm or more in the scanning direction, the composition of the film is suppressed from being deviated in the molecular layer at the initial stage of formation of the IGZO film. As a result, the properties of the IGZO film are prevented from being varied at the boundary between the IGZO film and the other member other than the IGZO film.

When the cathode unit 22 scans from the start position St to the end position En, the first shield plate 28a does not allow the sputtered particles SP having an incident angle θ of 30 ° or less among the sputtered particles SP discharged in the direction from the first sputtering region E1 toward the cathode unit 22 to reach the substrate S. Therefore, since the sputtering particles SP that reach the formation region R1 first are limited to the sputtering particles SP having the incident angle θ larger than 30 °, variations in the composition per unit thickness or unit area at the beginning of the formation of the IGZO film are suppressed.

The second shield plate 28b does not allow the sputtering particles SP having the incident angle θ of 30 ° or less among the sputtering particles SP discharged in the direction opposite to the direction from the second sputtering region E2 toward the cathode unit 22 to reach the substrate S. Therefore, the sputtering particles SP which are discharged from the first sputtering region E1 and reach the substrate S after the sputtering particles SP which reach the substrate S first are also limited to the sputtering particles having the incident angle θ larger than 30 °. As a result, the IGZO film is formed only by the sputtered particles SP whose incident angle θ is limited, and therefore variation in composition per unit thickness or unit area is suppressed in the entire thickness direction of the IGZO film.

When the IGZO film starts to be formed, the magnetic path scanning unit 29 arranges the magnetic path 25 at the first position P1. Therefore, compared to the case where the magnetic circuit 25 is disposed at another position between the first position P1 and the second position P2, the distance in the scanning direction between the first sputtering region E1 formed by the magnetic circuit 25 and the first shield plate 28a is the smallest. Therefore, the range of the incidence angle θ of the sputtering particles SP that collide with the first shield plate 28a is largest, and the sputtering particles SP having a larger incidence angle θ reach the vicinity of the first end Re1 of the formation region R1, compared to the case where the magnetic circuit 25 is disposed at another position. As a result, the variation in the composition of the IGZO film is further suppressed.

When the target 23 passes through the one-time facing region R2, since the magnetic circuit 25 performs one scan from the first position P1 toward the second position P2, the relative speed of the magnetic circuit with respect to the target 23 does not change. Therefore, the thickness of the compound film is suppressed from being deviated in the scanning direction of the target 23.

In the present embodiment, the configuration in which the distance D1 and the distance D2, the first deceleration position BP1 and the first acceleration position AP1, the second deceleration position BP2 and the second acceleration position AP2, and the start position St and the end position En are all arranged symmetrically with respect to the center of the substrate S in the scanning direction is exemplified, but these positions may be arranged asymmetrically in accordance with film characteristics such as the film thickness in the substrate S. Alternatively, it may be set so that only the relationships selected from the relationships between the distance D1 and the distance D2, between the first decelerating position BP1 and the first accelerating position AP1, between the second decelerating position BP2 and the second accelerating position AP2, and between the starting position St and the ending position En are symmetrical, and the relationships other than these relationships may be set to be asymmetrical.

Specifically, it can be exemplified that the ratio is set by setting the distance between the first acceleration position AP1 and the second acceleration position AP2 to 10 and the distance between the second deceleration position BP2 and the first deceleration position BP1 to 8.

Next, a sputtering method according to a second embodiment of the present invention will be described with reference to the drawings.

Fig. 8 is a structural diagram schematically showing the structure of the cathode unit of the present embodiment. The present embodiment is different from the first embodiment in the number of targets. The same reference numerals are used for the other components corresponding to those of the first embodiment, and the description thereof will be omitted.

[ Structure of cathode Unit 22 ]

In the present embodiment, as shown in fig. 8, the cathode unit 22 has a first cathode 22A and a second cathode 22B. Each of the first cathode 22A and the second cathode 22B includes a target 23, a backing plate 24, a magnetic circuit 25, and a magnetic circuit scanning unit 29. In the first cathode 22A and the second cathode 22B, the targets 23 having the respective cells are arranged in the scanning direction, and the respective surfaces 23a of the two targets 23 are included in the same plane parallel to the imaginary plane Pid.

When the cathode unit 22 is disposed at the start position St, the first cathode 22A is closer to the formation region R1 in the scanning direction than the second cathode 22B. In addition, in the first cathode 22A and the second cathode 22B, one ac power supply 26A is connected in parallel to each back plate 24.

A midpoint 23e3 (center position) of the target 23 is set between the first cathode 22A and the second cathode 22B.

The cathode unit 22 includes a scanning unit 27 for moving the cathode unit 22 in the scanning direction, and the scanning unit 27 moves the cathode unit 22 in the scanning direction while connecting the first cathode 22A and the second cathode 22B.

At this time, similarly to the first embodiment shown in fig. 5, the speed of the cathode unit 22 is accelerated until the midpoint 23e3 (center position) of the target 23 reaches the first acceleration position AP1 from the start position St, and becomes the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2 from the first acceleration position AP1, the cathode unit 22 moves at a constant speed at the first scanning speed V1. And, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the cathode unit 22 is accelerated to the second scanning speed V2.

Until the midpoint 23e3 (center position) of the target 23 reaches the second deceleration position BP2 from the second acceleration position AP2, the cathode unit 22 moves at a constant speed at the second scanning speed V2.

Then, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the cathode unit 22 is decelerated to the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the first deceleration position BP1 from the second deceleration position BP2, the cathode unit 22 moves at a uniform speed at the first scanning speed V1. Finally, the scanning is terminated by decelerating and stopping until the midpoint 23e3 (center position) of the target 23 reaches the end position En from the first deceleration position BP 1.

The cathode unit 22 includes a first shielding plate 28a and a second shielding plate 28B, the first shielding plate 28a is disposed between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 included in the first cathode 22A in the state where the cathode unit 22 is disposed at the start position St, and the second shielding plate 28B is disposed at a position farther from the first end Re1 of the formation region R1 than the second end 23e2 of the target 23 included in the second cathode 22B in the state where the cathode unit 22 is disposed at the start position St.

The shield plates 28a and 28B prevent the sputtering particles SP having the incidence angle θ within a predetermined range from among the plurality of sputtering particles SP discharged from the sputtering regions E1 and E2 of the first cathode 22A and the second cathode 22B from reaching the substrate S. Although the positions of the first shielding plate 28a and the second shielding plate 28b in the scanning direction are different from each other, the configuration related to the limitation of the sputtered particles SP that reach the substrate S is common. Therefore, the second shield plate 28b will be described in detail below, and the description of the first shield plate 28a will be omitted.

When the magnetic circuit 25 is disposed at the first position P1, the distance in the scanning direction between the first sputtering region E1 of the first cathode 22A and the second shield plate 28b is the largest. Therefore, the range of the incidence angle θ 3 of the sputtering particles SP that collide with the second shield plate 28b among the plurality of sputtering particles SP discharged in the direction opposite to the direction toward the cathode unit 22 from the first sputtering region E1 of the first cathode 22A is the smallest. The second shield plate 28b does not allow the sputtering particles SP having the incident angle θ 3 of 9 ° or less among the plurality of sputtering particles SP discharged in the direction opposite to the direction from the first sputtering region E1 of the first cathode 22A toward the cathode unit 22 to reach the substrate S.

Here, the plurality of sputtering particles SP discharged in the direction opposite to the direction toward the cathode unit 22 among the sputtering particles SP discharged from the first sputtering region E1 do not fly toward the respective sputtering regions E2 and 22B of the first cathode 22A, and therefore, the flight paths F of the plurality of sputtering particles SP discharged from the first sputtering region E1 pass through a region where the plasma density is high before reaching the substrate S, however, the flight distance until the sputtering particles SP having the incident angle θ 3 of 9 ° or less reach the substrate S after passing over the B ⊥ 0 region extending in the height direction from the other sputtering region is longer than the sputtering particles SP having the larger incident angle θ, and therefore, the number of times the sputtering particles SP collide with particles other than the active species such as the sputtering gas in the space passing over the B ⊥ 0 region where the plasma density is high becomes larger, and therefore, the energy of the sputtering particles SP becomes smaller, and the IGZO density of the film formed by the sputtering particles having the smaller incident angle θ becomes smaller, and as a result, the IGZO film becomes less dense and the IGZO film becomes less dense.

When the magnetic circuit 25 of the second cathode 22B is disposed at the first position P1, the second shield plate 28B does not allow some of the plurality of sputtered particles SP discharged from the second sputtering region E2 of the second cathode 22B to reach the substrate S, as in the case of the second shield plate 28B of the first embodiment. That is, the second shield plate 28B does not allow the sputtering particles SP having the incident angle θ 2 of 30 ° or less among the sputtering particles SP discharged in the direction opposite to the direction from the second sputtering region E2 of the second cathode 22B toward the cathode unit 22 to reach the substrate S. Therefore, the variation in the composition of the IGZO film per unit thickness or unit area is suppressed.

On the other hand, when each of the two magnetic circuits 25 is arranged at the second position P2, the distance in the scanning direction between the second sputtering region E2 of the second cathode 22B and the first shield plate 28a is largest. Therefore, the range of the incidence angle θ 3 of the sputtering particles SP that collide with the first shield plate 28a among the plurality of sputtering particles discharged from the second sputtering region E2 of the second cathode 22B toward the cathode unit 22 is the smallest. That is, like the second shield plate 28B, the first shield plate 28a does not allow any of the plurality of sputtering particles discharged from the second sputtering region E2 of the second cathode 22B in the direction toward the cathode unit 22 to reach the substrate S, the sputtering particles having the incident angle θ of 9 ° or less.

When the magnetic circuit 25 of the first cathode 22A is disposed at the second position P2, the first shield plate 28a does not allow some of the plurality of sputtered particles SP discharged from the first sputtering region E1 of the first cathode 22A to reach the substrate S, as in the first shield plate 28a of the first embodiment. That is, the first shield plate 28a does not allow the sputtering particles SP having the incident angle θ 2 of 30 ° or less among the sputtering particles SP discharged in the direction from the first sputtering region E1 of the first cathode 22A toward the cathode unit 22 to reach the substrate S.

In the present embodiment, the distance between the first acceleration position AP1 and the second acceleration position AP2 is set, so that the thickness of the IGZO film can be prevented from increasing at the edge portion of the substrate S. Meanwhile, by setting the ratio of the first scanning speed V1 to the second scanning speed V2, the film thickness of the IGZO film can be prevented from varying at the center of the substrate S.

Since the first shield plate 28a and the second shield plate 28b do not allow the sputtered particles having an incident angle of 9 ° or less to reach the formation region, the film density of the IGZO film is suppressed from decreasing.

Next, a sputtering method according to a third embodiment of the present invention will be described with reference to the drawings.

Fig. 9 is a schematic diagram showing the structure of the sputtering chamber according to the present embodiment. Fig. 10 is a diagram for explaining the sputtering operation of the present embodiment. Fig. 11 is a diagram for explaining a sputtering operation in the present embodiment.

The present embodiment is different from the first and second embodiments in the number of cathode units provided in the sputtering chamber 13. The same reference numerals are used for other components corresponding to those of the first and second embodiments, and the description thereof will be omitted.

[ Structure of sputtering Chamber 13 ]

In the present embodiment, the cathode device 18 includes a first cell 31 and a second cell 32. The first unit 31 and the second unit 32 are arranged in order from a position close to the first end Re1 of the formation region R1 in the scanning direction in the state of being arranged at the start position St.

Each of the first unit 31 and the second unit 32 includes a target 23, a back plate 24, a magnetic circuit 25, a dc power supply 26D, a first shield plate 28a, and a second shield plate 28b, and the targets 23 are arranged in the scanning direction in the two cathode units. The first unit 31 and the second unit 32 scan the facing regions R2 one by one in the scanning direction by one scanning section 27. Each of the first unit 31 and the second unit 32 further includes a magnetic path scanning unit 29, as in the cathode unit 22 of the first embodiment.

The first cell 31 and the second cell 32 have different main components of the material forming the target 23. The first unit 31 has, for example, a target 23 whose main component is silicon oxide, and the second unit 32 has, for example, a target 23 whose main component is niobium oxide. In addition, for example, 95% by mass of the material forming each target 23 is silicon oxide or niobium oxide, and preferably 99% by mass or more is silicon oxide or niobium oxide.

When the first unit 31 and the second unit 32 are disposed at the start position St, the distance between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 included in the first unit 31 is 150mm or more.

Further, a midpoint 23e3 (center position) of the target 23 is set in each of the first cell 31 and the second cell 32.

Here, as an example of the operation of the sputtering chamber 13, a case will be described where a laminated film of a silicon oxide film and a niobium oxide film is formed on the surface Sa of the substrate S as the formation region R1.

As shown in fig. 9, when the cathode apparatus 18 starts forming the laminated film, the first unit 31 disposed at the start position St starts discharging the sputtering particles SP. At this time, the distance D1 in the scanning direction between the first end Re1 of the formation region R1 and the first end 23e1 of the target 23 is 1500mm or more. Therefore, when the direct-current power is supplied to the target 23, most of the sputtering particles SP discharged from the target 23 hardly reach the substrate S regardless of the incident angle θ of the sputtering particles SP. Therefore, the composition of the film can be suppressed from being varied in the molecular layer at the initial stage of formation of the silicon oxide film.

As shown in fig. 10, by the first cell 31 moving in the scanning direction, the sputter area of the first cell 31 scans the opposing area R2 opposing the formation area R1 in the scanning direction.

At this time, similarly to the first embodiment shown in fig. 5, the speed of the first unit 31 is accelerated until the midpoint 23e3 (center position) of the target 23 reaches the first acceleration position AP1 from the start position St, and becomes the first scanning speed. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2 from the first acceleration position AP1, the first unit 31 moves at a constant speed at the first scanning speed V1. Also, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the first unit 31 is accelerated to the second scanning speed V2.

Until the midpoint 23e3 (center position) of the target 23 reaches the second deceleration position BP2 from the second acceleration position AP2, the first unit 31 is moved at a constant speed at the second scanning speed V2.

Then, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the first unit 31 decelerates to the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the first deceleration position BP1 from the second deceleration position BP2, the first unit 31 moves at a constant speed at the first scanning speed V1. Finally, the scanning is terminated by decelerating and stopping until the midpoint 23e3 (center position) of the target 23 reaches the end position En from the first deceleration position BP 1.

At this time, the sputtering particles SP that reach the substrate S are restricted by the first shielding plate 28a and the second shielding plate 28b to sputtering particles SP having an incident angle θ larger than 30 °. Therefore, the composition of the film can be suppressed from being varied in the initial layer of the silicon oxide film.

As shown in fig. 11, when the first unit 31 moves in the scanning direction and reaches the end position En, the second unit 32 disposed at the start position St starts to discharge the sputtered particles SP. When the first cell 31 is disposed at the end position En, the distance D1 between the second end 23e2 of the target 23 and the second end Re2 of the formation region R1 included in the first cell 31 is 150mm or more. Further, the scanning section 27 does not scan the second unit 32 while scanning the first unit 31 from the start position St toward the end position En.

The second unit 32 moves in the scanning direction from the start position St toward the end position En. Thereby, the sputter area of the second cell 32 scans the opposing area R2 opposite to the formation area R1 in the scanning direction.

At this time, similarly to the first embodiment shown in fig. 5, the speed of the second unit 32 is accelerated until the midpoint 23e (center position) of the target 23 reaches the first acceleration position AP1 from the start position St, and becomes the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2 from the first acceleration position AP1, the second unit 32 moves at a constant speed at the first scanning speed V1. And, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the second cell 32 is accelerated to the second scanning speed V2.

Until the midpoint 23e3 (center position) of the target 23 reaches the second deceleration position BP2 from the second acceleration position AP2, the second unit 32 moves at a constant speed at the second scanning speed V2.

Then, in a state where the midpoint 23e3 (center position) of the target 23 reaches the second acceleration position AP2, the second unit 32 decelerates to the first scanning speed V1. Thereafter, until the midpoint 23e3 (center position) of the target 23 reaches the first deceleration position BP1 from the second deceleration position BP2, the second unit 32 moves at a constant speed at the first scanning speed V1. Finally, the scanning is terminated by decelerating and stopping until the midpoint 23e3 (center position) of the target 23 reaches the end position En from the first deceleration position BP 1.

At this time, similarly to the first unit 31, the sputtering particles SP that reach the substrate S are restricted by the first shield plate 28a and the second shield plate 28b to sputtering particles SP having an incident angle θ larger than 30 °. Therefore, the composition of the film can be suppressed from varying in the initial layer of the niobium oxide film. When the second cell 32 is disposed at the end position En, the distance D1 between the second end 23e2 of the target 23 and the second end Re of the formation region R1 included in the second cell 32 is 150mm or more. In addition, while the scanner 27 scans the second unit 32 from the start position St toward the end position En, the scanner 27 does not scan the first unit 31.

According to the present embodiment, while the same effects as those of the first and second embodiments described above are obtained, the composition of the boundary between the silicon oxide film and the substrate S is suppressed from being varied in the laminated film composed of the silicon oxide film and the niobium oxide film, and the composition of the boundary between the niobium oxide film and the silicon oxide film is suppressed from being varied.

The above embodiments can be modified as appropriate in the following manner.

In the first and second embodiments, the main component of the material forming the target 23 may be an oxide semiconductor other than IGZO, for example, zinc oxide, nickel oxide, tin oxide, titanium oxide, vanadium oxide, indium oxide, strontium titanate, or the like.

In the first and second embodiments, the main component of the material forming the target 23 may be an oxide semiconductor other than IGZO, or an oxide semiconductor other than IGZO containing indium, for example, Indium Zinc Tin Oxide (IZTO), Indium Zinc Antimony Oxide (IZAO), Indium Tin Zinc Oxide (ITZO), Indium Zinc Oxide (IZO), Indium Antimony Oxide (IAO), or the like may be used.

The main component of the material forming the target 23 is not limited to IGZO, and may be an inorganic oxide such as Indium Tin Oxide (ITO) or aluminum oxide.

The main component of the material forming the target 23 may be a metal, a metal oxide, a semiconductor, or the like. In the case where a simple metal or a semiconductor is used as a main component of the material forming the target 23, a compound film such as an oxide film or a nitride film can be formed by a reaction between the sputtering particles SP discharged from the target 23 and plasma generated from the reaction gas.

The sputtering chamber 13 provided in the sputtering apparatus according to the third embodiment may not have the following structure: that is, when the sputtering particles SP start to be discharged toward the formation region R1, the two units of the first unit 31 and the second unit 32 are arranged at the start position St.

As shown in fig. 12, the sputtering chamber 13 provided in the sputtering apparatus according to the third embodiment may be configured such that the first unit 31 is disposed at the start position St and the second unit 32 is disposed at the end position En. In such a configuration, when the first unit 31 is disposed at the start position St, the distance D1 in the scanning direction between the first end 23e1 of the target 23 of the first unit 31 and the first end Re1 of the formation region R1 is preferably 150mm or more. On the other hand, when the second cell 32 is disposed at the end position En, the distance D1 in the scanning direction between the second end 23e2 of the target 23 of the second cell 32 and the second end Re2 of the formation region R1 is preferably 150mm or more.

When the laminated body is formed on the formation region R1, for example, the scanning section 27 moves the first unit 31 in the scanning direction from the start position St toward the end position En. Thereby, for example, a silicon oxide film is formed on the formation region R1. The scanner 27 moves the first unit 31 in the scanning direction from the end position En toward the start position St. At this time, the first unit 31 may discharge the sputtered particles SP to the formation region R1, or may not discharge the sputtered particles SP. Next, the scanner section 27 moves the second unit 32 in the scanning direction from the end position En toward the start position St. Thereby, for example, a niobium oxide film is formed on the formation region R1. The scanner 27 moves the second unit 32 in the scanning direction from the start position St to the end position En. At this time, the second unit 32 may discharge the sputtered particles SP to the formation region R1, or may not discharge the sputtered particles SP.

The number of times of movement in the scanning direction between the start position St and the end position En while the first unit 31 and the second unit 32 discharge the sputtered particles SP can be changed according to the thickness of the compound film formed in each unit.

The sputtering apparatus 10 may be configured to include two sputtering chambers 13 having two cathode units 22. In this configuration, since the cathode units 22 of the respective sputtering chambers 13 include the targets 23 having different main components of the forming material, a laminated body of two compound films can be formed on the surface Sa of the substrate S. The sputtering apparatus 10 may be configured as follows: that is, three or more sputtering chambers 13 each having one cathode unit 22 are provided, and the main components of the material forming the target 23 included in each cathode unit 22 are different from each other. According to this structure, a laminate composed of three or more compound films is formed on the surface Sa of the substrate S.

The first cell 31 of the third embodiment may include the target 23 whose main component of the forming material is a component other than silicon oxide, and the second cell 32 may include the target 23 whose main component of the forming material is a component other than niobium oxide. The main component of the material forming any one of the targets 23 may be any one of a metal, a metal compound, a semiconductor, and the like.

The sputtering chamber 13 of the third embodiment may have a configuration including three or more cathode units 22, and the main components of the materials forming the targets 23 included in the cathode units 22 may be different from each other or may be the same.

As shown in fig. 13, the cathode unit 22 of the second embodiment may be provided with a third shielding plate 28c in the scanning direction, and the third shielding plate 28c may be disposed between the target 23 of the first cathode 22A and the target 23 of the second cathode 22B. The protruding width of the third shield plate 28c in the width direction may be different from or the same as the protruding width of the first shield plate 28a and the second shield plate 28b in the width direction. The third shielding plate 28c is an example of the third shielding portion. Further, the third shield plate 28c in the scanning direction coincides with the midpoint 23e3 (center position).

When the cathode unit 22 moves in the scanning direction from the start position St toward the end position En, the distance between the first sputtering region E1 of the first cathode 22A and the third shield plate 28c in the scanning direction is the largest. However, the distance between the first sputtering region E1 and the third shield plate 28c in the scanning direction is smaller than the distance between the first sputtering region E1 and the second shield plate 28 b. Therefore, the range of the incident angle θ 4 of the sputtering particles SP that collide with the third shield plate 28c among the plurality of sputtering particles SP discharged in the direction opposite to the direction toward the cathode unit 22 from the first sputtering region E1 of the first cathode 22A is larger than 9 °. Therefore, the maximum value of the flight path F among the plurality of sputtering particles SP that reach the formation region R1 becomes smaller, and the maximum value of the number of times that the sputtering particles SP collide with other particles in the plasma also becomes smaller. As a result, the minimum value of the energy of the sputtered particles SP becomes large, and the film density of the IGZO film can be suppressed from decreasing.

On the other hand, when each of the two magnetic circuits 25 is arranged at the second position P2, the distance between the second sputtering region E2 of the second cathode 22B and the third shield plate 28c in the scanning direction is the largest. However, the distance between the second sputtering region E2 and the first shield plate 28a in the scanning direction is small. Therefore, the range of the incidence angle θ of the sputtering particles SP that collide with the third shield plate 28c among the plurality of sputtering particles SP discharged from the second sputtering region E2 of the second cathode 22B toward the cathode unit 22 is larger than 9 °. Therefore, the third shield plate 28c also acts on the sputtering particles SP discharged from the second cathode 22B in the same manner as the sputtering particles SP discharged from the first cathode 22A.

In the first to third embodiments, the magnetic circuit scanning section 29 moves the magnetic circuit 25 from the first position P1 toward the second position P2 in the scanning direction. Without being limited thereto, the magnetic circuit scanning unit 29 may move the magnetic circuit 25 from the second position P2 toward the first position P1 in the scanning direction. At this time, when the scanning section 27 scans the primary target 23 in the opposing region R2, the magnetic circuit scanning section 29 scans the primary magnetic circuit 25 from the second position P2 toward the first position P1, whereby the above-described effects can be obtained.

The magnetic circuit scanning unit 29 may be configured such that the magnetic circuit 25 scans a portion between the first end 23e1 and the second end 23e2 of the target 23 in the scanning direction. In this configuration, since the maximum value of the distance between each sputtering region and each shielding portion in the scanning direction is small, the shielding plate having a smaller projection width does not allow the sputtered particles SP having the same incident angle θ as that of each of the above-described embodiments to reach the formation region R1.

In the first to third embodiments, the cathode unit 22 includes the magnetic path scanning unit 29. Not limited to this, the cathode unit 22 may not include the magnetic path scanning unit 29, that is, the cathode unit 22 may be configured to fix the positions of the respective sputtering regions with respect to the target 23. Even in the case of such a configuration, by setting the speed of the midpoint 23e3 (center position) of the target 23 from the start position St to the end position En in the above-described manner, an appropriate film thickness distribution can be obtained.

In the cathode unit 22 of the second embodiment, the second shielding plate 28b may allow the sputtering particles SP having an incident angle θ of 9 ° or less among the sputtering particles SP discharged from the first sputtering region E1 of the first cathode 22A to reach the formation region R1. In addition, the first shield plate 28a may allow the sputtering particles SP having an incident angle θ of 9 ° or less among the sputtering particles SP discharged from the second sputtering region E2 of the second cathode 22B to reach the formation region R1.

In the first to third embodiments, the first shield plate 28a and the second shield plate 28b may not be configured as described above, and may be configured without providing a shield plate.

In the first to third embodiments, when the cathode unit 22 is disposed at the end position En, the distance between the second end Re2 of the formation region R1 and the second end 23e2 of the target 23 closest to the distance between the second end Re2 of the formation region R1 in the scanning direction may not be 150 mm. Even in the case of such a configuration, when the cathode unit 22 is disposed at the start position St, the above-described effect can be obtained if the distance between the first end Re1 of the formation region R1 and the second end 23e2 of the target 23 closest to the first end Re1 of the formation region R1 in the scanning direction is 150 mm.

The sputtering apparatus 10 may not include the carry-in/out chamber 11 and the pretreatment chamber 12, and the above-described effects can be obtained if the sputtering apparatus 10 includes the sputtering chamber 13. Alternatively, the sputtering apparatus 10 may be configured to include a plurality of pretreatment chambers 12.

The width of the substrate S in the conveying direction and the width of the substrate S in front of the paper surface are not limited to the above-described sizes, and can be changed as appropriate.

The sputtering gas may be a rare gas other than argon, and may be, for example, helium, neon, krypton, or xenon. The reaction gas may be an oxygen-containing gas other than oxygen, a nitrogen-containing gas, or the like, and may be changed according to the compound film formed in the sputtering chamber 13.

The cathode unit 22 of the second embodiment may be configured to include three or more cathodes including the target 23, the backing plate 24, the magnetic circuit 25, the ac power supply 26, and the magnetic circuit scanning unit 29.

The sputtering chamber 13 according to the third embodiment may be configured to include two cathode units 22 according to the second embodiment, that is, a cathode unit 22 including a first cathode unit 22A and a second cathode unit 22B.

The conditions for forming the IGZO film are not limited to those described in the above examples, and may be other conditions. What is important is the condition under which the IGZO film can be formed on the surface Sa of the substrate S.

As shown in fig. 14, the sputtering apparatus may also be embodied as a multi-roll sputtering apparatus 50. In this configuration, the sputtering apparatus 50 includes: a conveyance chamber 51 for mounting a conveyance robot 51R; and the following chambers connected to the conveyance chamber 51. That is, the conveyance chamber 51 is connected with: a carry-in/out chamber 52 for carrying in a substrate before film formation from the outside of the sputtering apparatus 50 and carrying out a substrate after film formation to the outside of the sputtering apparatus 50; a pretreatment chamber 53 for performing pretreatment required for film formation on the substrate; and a sputtering chamber 54 for forming a compound film on the substrate.

In the above embodiment, the first acceleration position AP1 is set to be more outside than the first end portion Re1 and the first deceleration position BP1 is set to be more outside than the second end portion Re2, but as shown in fig. 19, the first acceleration position AP1 may be set to be more inside than the first end portion Re1 and the first deceleration position BP1 may be set to be more inside than the second end portion Re 2. In this case, the film thickness distribution can be improved.

Here, patterns in which the second scanning speed V2 is 10000 mm/min, 5000/mm min, and 2500 mm/min are illustrated in the figure.