阅读说明：本技术 成膜方法 (Film forming method ) 是由 加藤寿 久保万身 高桥丰 于 2019-07-11 设计创作，主要内容包括：[课题]本公开提供能进行膜质的控制的成膜方法。[解决方案]具备如下工序：妨碍吸附区域的工序,使规定量的妨碍吸附自由基吸附在形成于基板上的吸附位点上,离散地形成妨碍吸附区域；使原料气体吸附的工序,使原料气体吸附在前述吸附位点上的未形成前述妨碍吸附区域的区域；和,使反应产物沉积的工序,使吸附于前述吸附位点上的前述原料气体与由等离子体活化了的反应气体反应,使反应产物沉积。([ problem ] to provide a film forming method capable of controlling the quality of a film. [ solution ] the method comprises the following steps: a step of forming an adsorption inhibiting region in a discrete manner by adsorbing a predetermined amount of adsorption inhibiting radicals to adsorption sites formed on a substrate; adsorbing the raw material gas in a region where the adsorption-impeding region is not formed on the adsorption sites; and depositing a reaction product by reacting the raw material gas adsorbed on the adsorption sites with the plasma-activated reaction gas.)

1. A film forming method includes the steps of:

forming an adsorption inhibiting region in which a predetermined amount of adsorption inhibiting radicals are adsorbed to adsorption sites formed on a substrate, thereby discretely forming adsorption inhibiting regions;

adsorbing the raw material gas in a region where the adsorption-impeding region is not formed on the adsorption site; and the combination of (a) and (b),

and depositing a reaction product by reacting the raw material gas adsorbed on the adsorption sites with a reaction gas activated by plasma.

2. The film forming method according to claim 1,

the interfering adsorbed radicals are generated using a remote plasma device.

3. The film forming method according to claim 1 or 2, wherein,

the activated reaction gas is activated by an inductively coupled plasma.

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

controlling the amount of adsorption of the raw material gas by controlling the amount of adsorption of the adsorption inhibiting radicals,

controlling the film density of the reaction product.

5. The film forming method according to claim 4,

by increasing the amount of adsorption of the adsorption inhibiting radicals, the amount of adsorption of the raw material gas is reduced,

increasing the film density of the reaction product.

6. The film forming method according to claim 4 or 5, wherein,

the amount of adsorption of the adsorption inhibiting radicals is set so that the amount of adsorption of the raw material gas is a predetermined amount or less.

7. The film forming method according to claim 6, wherein,

the step of forming the adsorption-impeding region is performed for a longer time than the step of adsorbing the raw material gas and the step of depositing the reaction product.

8. The film forming method according to claim 7, wherein,

the step of forming an adsorption-impeding region, the step of adsorbing the raw material gas, and the step of depositing the reaction product are periodically repeated to gradually deposit a molecular layer of the reaction product.

9. The film forming method according to any one of claims 1 to 8,

the adsorption-hindering free radical is a chlorine free radical,

the raw material gas is a gas containing chlorine and silicon,

the reaction gas is a nitriding gas,

the reaction product is a silicon nitride film.

10. The film forming method according to claim 9, wherein,

the predetermined amount of the raw material gas adsorption amount is in a range of more than 0.008 nm/cycle and 0.042 nm/cycle or less.

11. The film forming method according to claim 10, wherein,

the method further includes, between the step of forming an adsorption-impeding region and the step of adsorbing the source gas, and between the step of adsorbing the source gas and the step of depositing the silicon nitride film, the steps of: a purge gas is supplied to the surface of the substrate.

12. The film forming method according to claim 11, wherein,

before the step of forming the adsorption-impeding region in the 1 st stage, the method further includes the steps of: and supplying a nitriding gas activated by plasma to the surface of the substrate to nitride the surface of the substrate.

13. The film forming method according to claim 11 or 12,

the substrate is placed along a circumferential direction on a surface of a turntable provided in a processing chamber,

a chlorine radical adsorption region capable of supplying the chlorine radicals to the turntable, a 1 st purge region capable of performing the purge gas on the turntable, a raw material gas adsorption region capable of supplying the raw material gas to the turntable, a 2 nd purge region capable of supplying the purge gas to the turntable, and a nitriding region capable of supplying the activated nitriding gas to the turntable are provided above the turntable in the circumferential direction of the turntable,

performing the step of forming an adsorption hindering region by rotating the turntable 1 st predetermined number of times while supplying the chlorine radicals in the chlorine radical adsorption region, supplying the purge gas in the 1 st purge region and the 2 nd purge region, and supplying neither the raw material gas in the raw material gas adsorption region nor the activated nitriding gas in the nitriding region,

the step of adsorbing the raw material gas and the step of depositing the silicon nitride film are performed by rotating the turntable 2 nd predetermined number of times in a state where the chlorine radicals are supplied to the chlorine radical adsorption region, the purge gas is supplied to the 1 st purge region and the 2 nd purge region, the raw material gas is supplied to the raw material gas adsorption region, and the activated nitride gas is supplied to the nitride region.

14. The film forming method according to claim 13, wherein,

the 1 st predetermined number is equal to or greater than the 2 nd predetermined number.

15. The film forming method according to claim 13 or 14, wherein,

the 2 nd prescribed number is 1.

16. The film forming method according to any one of claims 13 to 15,

the amount of adsorbed chlorine radicals is adjusted by the 1 st predetermined number of times.

17. The film forming method according to any one of claims 13 to 16,

the chlorine radical adsorption region, the 1 st purge region, the raw material gas adsorption region, the 2 nd purge region, and the nitridation region are arranged along a rotation direction of the turntable.

18. The film forming method according to any one of claims 13 to 17,

the chlorine radicals are supplied by a shower head.

19. The film forming method according to any one of claims 1 to 18,

the reaction gas is gas containing ammonia.

20. The film forming method according to any one of claims 1 to 19,

the raw material gas is dichlorosilane.

Technical Field

The present disclosure relates to a film forming method.

Background

Conventionally, there has been known a method of forming a nitride film by repeating the following steps to form a nitride film in a fine recess: an adsorption step of adsorbing a film formation source gas containing chlorine and an element constituting a nitride film to be formed on a target substrate having a fine concave portion formed on a surface thereof; and a nitriding step of nitriding the adsorbed film formation source gas with a nitriding active material, wherein the nitriding step generates NH as the nitriding active material^＊Active substance and N^＊The concentration of the active material is controlled to change the region in the fine recessed portions where the film forming source gas is adsorbed (see, for example, patent document 1).

In the method of forming the nitride film, NH is used prior to the film formation stage^＊Performing a nitriding step mainly composed of an active material to form a conformal nitride film, and performing a subsequent nitriding step from N^＊Continuously decreasing N in a state where the concentration of the active material is high^＊The concentration of the active material is set to a film forming stage in which the nitride film is grown from the bottom of the fine recessed portion. Thereby, a nitride film is grown from the bottom of the trench to the top, and then NH is added^＊The active material is controlled to grow in a conformal manner in a high state, and the nitride film can be embedded without forming voids or seams in the micro-groove.

Disclosure of Invention

Problems to be solved by the invention

In order to modify the nitride film, it is necessary to activate the nitriding gas with plasma to strengthen the nitriding force, but even if the plasma nitriding is continued for a long time, the state may be saturated and the film quality may not be improved. Further, it is very difficult to control the film quality, and if the above-mentioned saturation state is reached, an effective measure cannot be found in many cases.

Accordingly, the present disclosure provides: a film forming method capable of controlling the quality of a film.

Means for solving the problems

In order to achieve the above object, a film forming method according to one aspect of the present disclosure includes:

forming an adsorption inhibiting region in which a predetermined amount of adsorption inhibiting radicals are adsorbed to adsorption sites formed on a substrate, thereby discretely forming adsorption inhibiting regions;

adsorbing the raw material gas in a region where the adsorption-impeding region is not formed on the adsorption sites; and the combination of (a) and (b),

and depositing a reaction product by reacting the raw material gas adsorbed on the adsorption sites with a reaction gas activated by plasma.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the film quality of the deposited film can be controlled.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a film deposition apparatus that can be used in a film deposition method according to an embodiment of the present disclosure.

Fig. 2 is a schematic perspective view showing the structure in the vacuum chamber of the film forming apparatus.

Fig. 3 is a schematic plan view showing the structure in the vacuum chamber of the film forming apparatus.

FIG. 4 is a schematic cross-sectional view of a vacuum chamber of the film deposition apparatus along a concentric circle of a turntable.

FIG. 5 is another schematic cross-sectional view of the film forming apparatus.

Fig. 6 is a schematic cross-sectional view showing a plasma generation source provided in the film formation apparatus.

Fig. 7 is another schematic cross-sectional view showing a plasma generator provided in the film formation apparatus.

Fig. 8 is a schematic plan view showing a plasma generator provided in the film formation apparatus.

Fig. 9 is a schematic plan view showing an example of the film forming apparatus.

Fig. 10 is a partial sectional view for explaining the 3 rd process field P3 in the film deposition apparatus.

Fig. 11 is a plan view showing an example of the lower surface of the shower head.

Fig. 12 is a diagram illustrating a series of steps of an example of a film formation method according to an embodiment of the present disclosure.

Fig. 13 is a diagram for explaining a film formation method of a comparative example.

Fig. 14 is a diagram for explaining the film formation method according to the present embodiment.

Fig. 15 shows the results of the film formation method according to the comparative example.

Fig. 16 is a graph showing the cycle rate at which a predetermined etching rate is achieved by variously changing the cycle rate by carrying out the film formation method according to the present embodiment.

Fig. 17 is a graph showing the relationship between the cycle rate and the film density in the present example and the comparative example.

Fig. 18 is a graph showing the relationship between the flow rate of chlorine gas and the circulation rate in the present embodiment and the comparative example.

Description of the reference numerals

1 vacuum vessel

2 rotating table

4 convex part

7 Heater Unit

11 Top plate

12 Container body

15 delivery port

24 recess

31-33 reactive gas nozzle

41. 42 split gas nozzle

80. 90 plasma generator

91 plasma generating part

93 shower head

130-132 gas supply source

140 adsorption sites

150 interfere with the adsorption zone

151 chlorine radical

160 raw material gas

161 Dichlorosilane

170 reaction gas

171 Ammonia

180 reaction product

181 silicon nitride film

P1-P3 treatment region

W wafer

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[ film Forming apparatus ]

First, a film deposition apparatus suitable for use in the film deposition method according to the embodiment of the present invention will be described. Referring to fig. 1 to 3, the film deposition apparatus according to the present embodiment includes: a flat vacuum container 1 having a substantially circular planar shape; and a turntable 2 provided in the vacuum chamber 1 and having a rotation center along the center of the vacuum chamber 1. The vacuum chamber 1 is a processing chamber for performing a film formation process on the surface of a wafer accommodated therein. The vacuum container 1 has: a container body 12 having a bottomed cylindrical shape; and a top plate 11 that is air-tightly and detachably disposed on the upper surface of the container body 12 via a sealing member 13 (fig. 1) such as an O-ring.

The turntable 2 is fixed at the center to a cylindrical core 21, and the core 21 is fixed to the upper end of a rotating shaft 22 extending in the vertical direction. The rotary shaft 22 penetrates the bottom 14 of the vacuum chamber 1, and the lower end thereof is attached to a driving unit 23 for rotating the rotary shaft 22 (fig. 1) about the plumb axis. The rotary shaft 22 and the driving unit 23 are housed in a cylindrical case 20 having an open top surface. The flange portion of the casing 20 provided on the upper surface thereof is airtightly attached to the lower surface of the bottom portion 14 of the vacuum chamber 1, and the airtight state between the internal atmosphere and the external atmosphere of the casing 20 is maintained.

As shown in fig. 2 and 3, a circular recess 24 for placing a plurality of (5 in the illustrated example) semiconductor wafers (hereinafter, referred to as "wafers") W as substrates is provided in the surface portion of the turntable 2 along the rotational direction (circumferential direction). In fig. 3, the wafer W is shown only in 1 recess 24 for convenience. The recess 24 has an inner diameter slightly larger than the diameter of the wafer W, for example, 4mm, and a depth substantially equal to the thickness of the wafer W. Therefore, if the wafer W is accommodated in the recess 24, the front surface of the wafer W and the front surface of the turntable 2 (the region where the wafer W is not placed) have the same height. Through holes (none of which is shown) are formed in the bottom surface of the recess 24, and 3 lift pins, for example, for supporting the back surface of the wafer W and lifting and lowering the wafer W are inserted therethrough.

Fig. 2 and 3 are diagrams for explaining the structure inside the vacuum chamber 1, and the top plate 11 is not shown for convenience of explanation. As shown in fig. 2 and 3, a reaction gas nozzle 31, a reaction gas nozzle 32, a reaction gas nozzle 33, and separation gas nozzles 41 and 42, which are made of, for example, quartz, are arranged above the turntable 2 at intervals in the circumferential direction of the vacuum chamber 1 (the rotation direction of the turntable 2 (arrow a in fig. 3)). In the illustrated example, the separation gas nozzle 41, the reaction gas nozzle 31, the separation gas nozzle 42, the reaction gas nozzle 32, and the reaction gas nozzle 33 are arranged in the order of the separation gas nozzle 41, the reaction gas nozzle 31, the separation gas nozzle 42, the reaction gas nozzle 32, and the reaction gas nozzle 33 in the clockwise direction (the rotation direction of the turntable 2) from the later-described delivery port 15. These nozzles 31, 32, 33, 41, and 42 are introduced from the outer peripheral wall of the vacuum chamber 1 into the vacuum chamber 1 by fixing gas introduction ports 31a, 32a, 33a, 41a, and 42a (fig. 3) which are base end portions of the nozzles 31, 32, 33, 41, and 42 to the outer peripheral wall of the chamber body 12, and are attached so as to extend horizontally in the radial direction of the chamber body 12 with respect to the turntable 2.

In the present embodiment, as shown in fig. 3, the reaction gas nozzle 31 is connected to a source 130 of a source gas via a pipe 110, a flow controller 120, and the like. The reaction gas nozzle 32 is connected to a reaction gas supply source 131 via a pipe 111, a flow rate controller 121, and the like. The reaction gas nozzle 33 is connected to a supply source 132 for preventing adsorption of gas through a pipe 112, a flow rate controller 122, and the like. The separation gas nozzles 41 and 42 are each connected to a supply source (not shown) of the separation gas via a pipe, a flow rate control valve, and the like (not shown). As the separation gas, a rare gas such as helium (He) or argon (Ar), or nitrogen (N) can be used₂) And inert gases such as gases. In this embodiment, an example in which Ar gas is used will be described.

The reaction gas nozzles 31, 32, and 33 have a plurality of gas discharge holes 35 that open toward the turntable 2 and are arranged at intervals of, for example, 10mm in the longitudinal direction of the reaction gas nozzles 31, 32, and 33. The area below the reaction gas nozzle 31 is a 1 st processing area P1 for adsorbing the source gas onto the wafer W. The lower region of the reaction gas nozzle 32 is the 2 nd process region P2 in which a reaction gas capable of generating a reaction product by reacting with the source gas adsorbed on the wafer W in the 1 st process region P1 and a molecular layer of the reaction product is generated. The molecular layer of the reaction product constitutes a thin film to be formed. If necessary, the reaction gas may be supplied to the 2 nd processing region P2 at an initial stage when the wafer W is placed on the turntable 2 and the source gas is not supplied to the wafer W. When a nitriding gas such as ammonia is used as the reaction gas, the surface of the wafer W is nitrided before the source gas is supplied. This nitriding is for forming adsorption sites of the source gas on the surface of the wafer W, and may be performed as necessary. The region below the reaction gas nozzle 33 is a 3 rd processing region P3 in which radicals are prevented from being adsorbed by the reaction product or adsorption sites generated in the 2 nd processing region P2, and an adsorption-preventing region is formed on the surface of the wafer W. Here, the 1 st processing region P1 is a region to which the source gas is supplied, and therefore, may be referred to as a source gas supply region P1. Similarly, the 2 nd processing region P2 is a region to which a reaction gas that reacts with the source gas to form a reaction product is supplied, and therefore, may be referred to as a reaction gas supply region P2. The 3 rd processing region P3 is a region where adsorption of radicals is inhibited, and therefore, may be referred to as an adsorption-inhibiting radical supply region P3.

The source gas may be a silicon-containing gas or a metal-containing gas, depending on the type of the deposited film. The reaction gas may be any gas that reacts with the raw material gas to form a reaction product, and various gases may be used depending on the type of the deposited thin film. For example, in the case of forming an oxide film, an oxidizing gas such as oxygen may be used, and in the case of forming a nitride film, a nitriding gas such as ammonia may be used. In addition, various gases can be used depending on the type of the thin film as long as the adsorption-inhibiting gas inhibits adsorption of the raw material gas by the activation energy of the plasma or the like, thereby inhibiting adsorption of radicals.

However, in the following embodiments, for ease of explanation, an example will be described in which a gas containing silicon and chlorine is used as a raw material gas, a nitriding gas is used as a reaction gas, and a chlorine gas is used as an adsorption inhibiting gas. When chlorine is used as the adsorption inhibiting gas, the adsorption inhibiting radicals become chlorine radicals. However, the raw material gas, the reaction gas and the adsorption-inhibiting gas are not limited to these, and are as described above.

A plasma generator 90 is provided around, for example, above or on the side of the 3 rd processing region P3. Further, a plasma generator 80 is provided above the 2 nd processing region P2. In fig. 3, the plasma generators 80, 90 are shown in simplified broken line representation. The plasma generator 90 is constituted by a remote plasma generating device for generating chlorine radicals. On the other hand, the Plasma generator 80 may be of any type, and may be constituted by an ICP (Inductively Coupled Plasma) Plasma generator, for example. The details of the plasma generators 80 and 90 are as follows.

As described above, an example in which a gas containing silicon and chlorine is selected as the raw material gas will be described. For example, when the film is a silicon nitride (SiN) film, dichlorosilane (DCS, SiH) is selected₂Cl₂) And the like, gases containing silicon and chlorine. As the source gas, various gases can be used as long as they are a gas containing silicon and chlorine. For example, monochlorosilane (SiH) may be used in addition to dichlorosilane depending on the purpose₃Cl), trichlorosilane (SiHCl)₃) Hexachlorodisilane (Si)₂Cl₆) And the like. DCS is an example of such a gas containing silicon and chlorine.

Further, as the nitriding gas, ammonia (NH) is usually selected₃) A gas. When the nitriding gas is supplied by plasma activation, nitrogen (N) may be selected₂) A gas. The nitriding gas may contain a carrier gas such as Ar in addition to ammonia.

The chlorine radicals supplied from the 3 rd reaction nozzle 33 have the following effects: adsorption-inhibiting regions that inhibit the raw material gas supplied from the 1 st reaction gas nozzle 31 from adsorbing on the wafer W are discretely and dispersedly formed on the surface of the wafer. The film deposition apparatus and the film deposition method according to the present embodiment are controlled such that: the adsorption inhibiting region is formed so as to be dispersed, and the raw material gas is not adsorbed to the entire surface of the wafer W in a saturated state but is locally adsorbed to the entire surface of the wafer W in a dispersed state. The details of the film forming method according to the present embodiment are as follows. In fig. 2 and 3, the horizontally extending nozzle is shown as the 3 rd reaction nozzle 33, but the 3 rd reaction nozzle 33 may be configured as a shower head. In fig. 2 and 3, an example in which the 3 rd reaction nozzle 33 is configured as a nozzle extending horizontally will be described, and a case in which it is configured as a shower head will be described later.

Referring to fig. 2 and 3, the vacuum chamber 1 is provided with 2 convex portions 4. The convex portion 4 is attached to the back surface of the top plate 11 so as to protrude toward the turntable 2, as will be described later, in order to form the separation region D together with the separation gas nozzles 41 and 42. The convex portion 4 has a fan-shaped planar shape with a top portion cut into an arc shape, and in the present embodiment, is connected to the protruding portion 5 (described later) by an inner arc, and is disposed so that an outer arc thereof extends along the inner peripheral surface of the container main body 12 of the vacuum container 1.

Fig. 4 shows a cross section of the vacuum chamber 1 from the reaction gas nozzle 31 to the reaction gas nozzle 32 along a concentric circle of the turntable 2. As shown in the drawing, since the convex portion 4 is attached to the rear surface of the top plate 11, there are: a flat low top surface 44 (1 st top surface) as a lower surface of the convex portion 4; and a top surface 45 (2 nd top surface) located on both sides of the top surface 44 in the circumferential direction and higher than the top surface 44. The top surface 44 has a planar shape of a sector with a top portion cut into an arc shape. As shown in the drawing, the convex portion 4 is formed with a groove portion 43, the groove portion 43 is formed at the circumferential center so as to extend in the radial direction, and the separation gas nozzle 42 is housed in the groove portion 43. The other convex portion 4 is similarly formed with a groove portion 43 in which the separation gas nozzle 41 is housed. Further, reaction gas nozzles 31 and 32 are provided in spaces below the high ceiling surface 45, respectively. These reaction gas nozzles 31 and 32 are provided in the vicinity of the wafer W, separately from the top surface 45. As shown in fig. 4, the reaction gas nozzles 31 are provided in the space 481 on the right side below the raised ceiling 45, and the reaction gas nozzles 32 are provided in the space 482 on the left side below the raised ceiling 45.

Further, a plurality of gas discharge holes 42h (see fig. 4) opening toward the turntable 2 are arranged at intervals of, for example, 10mm in the longitudinal direction of the separation gas nozzles 41 and 42 in the separation gas nozzles 41 and 42 accommodated in the groove portions 43 of the convex portion 4.

The top surface 44 forms a separation space H as a narrow space with respect to the turntable 2. If Ar gas is supplied from the discharge hole 42H of the separation gas nozzle 42, the Ar gas flows into the space 481 and the space 482 through the separation space H. At this time, the volume of the separation space H is smaller than the volumes of the spaces 481 and 482, and therefore, the pressure of the separation space H can be made higher than the pressures of the spaces 481 and 482 by the Ar gas. That is, a separation space H having a high pressure is formed between the spaces 481 and 482. In addition, the Ar gas flowing out from the separation space H to the spaces 481 and 482 acts as a counter flow to the 1 st reactive gas from the 1 st region P1 and the 2 nd reactive gas from the 2 nd region P2. Therefore, the raw material gas from the 1 st zone P1 and the reaction gas from the 2 nd zone P2 are separated by the separation space H. This can prevent the reaction gas from being mixed with the raw material gas in the vacuum chamber 1.

The height H1 of the ceiling surface 44 from the upper surface of the turntable 2 is preferably set to a height suitable for making the pressure in the separation space H higher than the pressures in the spaces 481 and 482, taking into account the pressure in the vacuum chamber 1 during film formation, the rotation speed of the turntable 2, the supply amount of the supplied separation gas (Ar gas), and the like.

On the other hand, a protrusion 5 (fig. 2 and 3) surrounding the outer periphery of the core 21 of the fixed turntable 2 is provided on the lower surface of the top plate 11. In the present embodiment, the protruding portion 5 is continuous with the portion of the convex portion 4 on the rotation center side, and the lower surface thereof is formed to have the same height as the top surface 44.

Fig. 1 referred to above is a cross-sectional view taken along line I-I' of fig. 3, showing the region where the top surface 45 is provided. On the other hand, fig. 5 is a sectional view showing a region where the top surface 44 is provided. As shown in fig. 5, a bent portion 46 bent in an L-shape is formed at the peripheral edge portion of the fan-shaped convex portion 4 (the portion on the outer edge side of the vacuum chamber 1) so as to face the outer end surface of the turntable 2. The bent portion 46 suppresses the reaction gas from entering from both sides of the separation region D, and suppresses the mixing of both reaction gases, as in the case of the convex portion 4. Since the fan-shaped convex portion 4 is provided on the top plate 11 and the top plate 11 is formed to be detachable from the container body 12, a slight gap is formed between the outer peripheral surface of the curved portion 46 and the container body 12. The gap between the inner peripheral surface of the curved portion 46 and the outer end surface of the turntable 2 and the gap between the outer peripheral surface of the curved portion 46 and the container body 12 are set to have the same size as the height of the top surface 44 from the upper surface of the turntable 2, for example.

The inner peripheral wall of the container body 12 is formed as a vertical surface close to the outer peripheral surface of the curved portion 46 in the separation region D as shown in fig. 4, but is recessed outward from a portion facing the outer peripheral surface of the turntable 2 to the bottom portion 14 in a portion other than the separation region D as shown in fig. 1, for example. Hereinafter, for convenience of explanation, a portion having a substantially rectangular cross-sectional recess will be referred to as an exhaust region. Specifically, the exhaust region communicating with the 1 st process region P1 is referred to as the 1 st exhaust region E1, and the regions communicating with the 2 nd and 3 rd process regions P2 and P3 are referred to as the 2 nd exhaust region E2. As shown in fig. 1 to 3, the 1 st exhaust port 610 and the 2 nd exhaust port 620 are formed in the bottom portions of the 1 st exhaust region E1 and the 2 nd exhaust region E2, respectively. As shown in fig. 1, the 1 st exhaust port 610 and the 2 nd exhaust port 620 are connected to, for example, a vacuum pump 640 as a vacuum exhaust means through respective exhaust pipes 630. Further, a pressure controller 650 is provided between the vacuum pump 640 and the exhaust pipe 630.

As shown in fig. 2 and 3, the separation region H is not provided between the 2 nd processing region P2 and the 3 rd processing region P3, but in fig. 3, a housing for partitioning the space on the turntable 2 is provided in the region indicated as the plasma generator 80, 90. Thereby, the space of the 2 nd processing region P2 and the 3 rd processing region P3 is partitioned. Details of this point will be described later.

As shown in fig. 1 and 5, a heater unit 7 serving as a heating means is provided in a space between the turntable 2 and the bottom 14 of the vacuum chamber 1, and the wafer W on the turntable 2 is heated to a temperature (for example, 400 ℃) determined by a process recipe through the turntable 2. An annular cover member 71 (fig. 5) is provided below the turntable 2 in order to divide the atmosphere from the space above the turntable 2 to the exhaust areas E1 and E2 and the atmosphere in which the heater unit 7 is provided, and to suppress the intrusion of gas into the area below the turntable 2. The covering member 71 includes: an inner member 71a provided to face the outer edge portion of the turntable 2 from below and to be located on the outer peripheral side of the outer edge portion; and an outer member 71b provided between the inner member 71a and the inner wall surface of the vacuum chamber 1. The outer member 71b is provided below the bent portion 46 formed at the outer edge portion of the convex portion 4 in the separation region D so as to be adjacent to the bent portion 46, and the inner member 71a surrounds the heater unit 7 over the entire circumference below the outer edge portion of the turntable 2 (and below a portion slightly outside the outer edge portion).

The bottom portion 14 at a position offset from the rotation center of the space where the heater unit 7 is disposed protrudes upward so as to be close to the core portion 21 near the center of the lower surface of the turntable 2, thereby forming a protruding portion 12 a. The protruding portion 12a and the core portion 21 form a narrow space, and a gap between the inner circumferential surface of a through hole penetrating the bottom portion 14 and through which the rotary shaft 22 penetrates and the rotary shaft 22 is narrowed, and these narrow spaces communicate with the housing 20. The casing 20 is provided with a purge gas supply pipe 72 for supplying Ar gas as a purge gas into a narrow space to purge the space. Further, a plurality of purge gas supply pipes 73 (one purge gas supply pipe 73 is shown in fig. 5) for purging the arrangement space of the heater unit 7 are provided at the bottom 14 of the vacuum chamber 1 below the heater unit 7 at predetermined angular intervals in the circumferential direction. Further, between the heater unit 7 and the turntable 2, a cover member 7a is provided to cover a space from an inner peripheral wall of the outer member 71b (an upper surface of the inner member 71 a) to an upper end portion of the protruding portion 12a in the circumferential direction in order to suppress intrusion of the gas into a region where the heater unit 7 is provided. The cover member 7a may be made of quartz, for example.

A separation gas supply pipe 51 is connected to a central portion of the top plate 11 of the vacuum chamber 1, and Ar gas as a separation gas is supplied to a space 52 between the top plate 11 and the core 21. The separation gas supplied to the space 52 is discharged along the surface of the turntable 2 on the wafer mounting region side to the peripheral edge through the narrow gap 50 between the protrusion 5 and the turntable 2. Space 50 may be maintained at a pressure higher than spaces 481 and 482 by the separation gas. Therefore, the material gas supplied to the 1 st processing region P1 and the nitriding gas supplied to the 2 nd processing region P2 can be prevented from being mixed by the space 50 through the center region C. That is, the space 50 (or the central region C) can function similarly to the separation space H (or the separation region D).

As shown in fig. 2 and 3, a transfer port 15 for transferring a wafer W as a substrate between the outer transfer arm 10 and the turntable 2 is formed in the side wall of the vacuum chamber 1. The transfer port 15 is opened and closed by a gate valve, not shown. Since the wafer W is transferred between the transfer arm 10 and the wafer placement area, i.e., the recess 24, of the turntable 2 at a position facing the transfer port 15, a transfer lift pin for lifting the wafer W from the back surface and a lift mechanism (neither of which is shown) for the transfer lift pin are provided at a position corresponding to the transfer position below the turntable 2 so as to penetrate the recess 24.

Next, the plasma generator 80 will be described with reference to fig. 6 to 8. Fig. 6 is a schematic cross-sectional view of the plasma generator 80 along the radial direction of the turntable 2, fig. 7 is a schematic cross-sectional view of the plasma generator 80 along the direction orthogonal to the radial direction of the turntable 2, and fig. 8 is a schematic plan view showing the plasma generator 80. In these figures, some components are simplified for convenience of illustration.

Referring to fig. 6, the plasma generator 80 is made of a high-frequency-transmissive material, has a concave portion recessed from an upper surface, and includes: a frame member 81 fitted in an opening 11a formed in the top plate 11; a faraday shield 82 housed in the recess of the frame member 81 and having a substantially box-like shape with an open upper portion; an insulating plate 83 disposed on the bottom surface of the faraday shield 82; and a coil-shaped antenna 85 supported above the insulating plate 83 and having a substantially octagonal upper surface shape.

The opening 11a of the top plate 11 has a plurality of stepped portions, and a groove portion is formed in one of the stepped portions over the entire circumference, and a sealing member 81a such as an O-ring is fitted into the groove portion. On the other hand, the frame member 81 has a plurality of step portions corresponding to the step portions of the opening portion 11a, and if the frame member 81 is fitted into the opening portion 11a, the back surface of one of the step portions comes into contact with the sealing member 81a of the groove portion of the opening portion 11a, whereby airtightness between the top plate 11 and the frame member 81 is maintained. As shown in fig. 6, a pressing member 81c is provided along the outer periphery of the frame member 81 fitted into the opening 11a of the top plate 11, and the frame member 81 presses the top plate 11 downward. Therefore, the airtightness between the top plate 11 and the frame member 81 can be maintained more reliably.

The lower surface of the frame member 81 faces the turntable 2 in the vacuum chamber 1, and a projection 81b projecting downward (toward the turntable 2) is provided on the outer periphery of the lower surface of the frame member 81 over the entire periphery. The lower surface of the projection 81b is adjacent to the surface of the turntable 2, and a space (hereinafter, the 3 rd processing region P3) is defined above the turntable 2 by the projection 81b, the surface of the turntable 2, and the lower surface of the frame member 81. It should be noted that the distance between the lower surface of the protrusion 81b and the surface of the turntable 2 and the height H1 from the top surface 11 of the separation space H (fig. 4) to the upper surface of the turntable 2 may be substantially the same.

The reaction gas nozzles 32 penetrating the protrusions 81b extend in the 2 nd processing region P2. In the present embodiment, as shown in fig. 6, a nitriding gas supply source 131 filled with a nitriding gas is connected to the reaction gas nozzle 32 through a flow rate controller 121 via a pipe 111. The nitriding gas may be, for example, a gas containing ammonia (NH)₃) The gas of (2) may specifically be ammonia (NH)₃) Mixed gas with argon (Ar). The nitriding gas, which is controlled by the flow rate controller 121, is activated in the plasma generator 80 at a predetermined flow rateThe 2 nd processing region P2. In the case where a mixed gas of ammonia and argon gas is used as the nitriding gas, ammonia and argon gas may be supplied separately, and fig. 6 illustrates a state where the mixed gas is supplied to the reaction gas nozzle 32 for convenience of explanation.

The reactive gas nozzle 32 has a plurality of discharge holes 35 formed at predetermined intervals (for example, 10mm) along the longitudinal direction thereof, and the chlorine gas is discharged from the discharge holes 35. As shown in fig. 7, the discharge hole 35 is inclined from the direction perpendicular to the turntable 2 toward the upstream side in the rotation direction of the turntable 2. Therefore, the gas supplied from the reaction gas nozzle 32 is discharged in the direction opposite to the rotation direction of the turntable 2, specifically, toward the gap between the lower surface of the protrusion 81b and the surface of the turntable 2. This can suppress the inflow of the reaction gas and the separation gas into the 2 nd processing region P2 from the space below the ceiling surface 45 located on the upstream side of the plasma generator 80 in the rotation direction of the turntable 2. In addition, since the projection 81b formed along the outer periphery of the lower surface of the frame member 81 is adjacent to the surface of the turntable 2 as described above, the pressure in the 2 nd processing region P2 can be easily maintained high by the gas from the reaction gas nozzle 32. This also suppresses the inflow of the reaction gas and the separation gas into the 2 nd processing region P2.

In this manner, the frame member 81 plays a role of separating the 2 nd processing region P2 from the surroundings. Thus, a film deposition apparatus according to an embodiment of the present invention includes: a plasma generator 80; and a frame member 81 for dividing the 2 nd processing region P2.

The faraday shield 82 is made of a conductive material such as metal, and is grounded although not shown. As clearly shown in fig. 8, a plurality of slits 82s are formed in the bottom of the faraday shield 82. Each slit 82s extends substantially orthogonally to a corresponding side of the antenna 85 having a substantially octagonal planar shape.

As shown in fig. 7 and 8, the faraday shield 82 has support portions 82a bent outward at 2 positions at the upper end. The support portion 82a is supported by the upper surface of the frame member 81, and the faraday shield 82 is supported at a predetermined position in the frame member 81.

The insulating plate 83 is made of, for example, quartz glass, has a size slightly smaller than the bottom surface of the faraday shield 82, and is placed on the bottom surface of the faraday shield 82. The insulating plate 83 insulates the faraday shield 82 from the antenna 85, and transmits the high frequency radiated from the antenna 85 downward.

The antenna 85 is formed by winding a copper hollow tube (pipe) by, for example, 3 times so that the planar shape thereof is substantially octagonal. Cooling water can be circulated in the pipe, and thus the antenna 85 can be prevented from being heated to a high temperature by the high frequency supplied to the antenna 85. The antenna 85 is provided with an upright portion 85a, and the upright portion 85a is provided with a support portion 85 b. The support portion 85b maintains the antenna 85 at a predetermined position in the faraday shield 82. Further, a high-frequency power supply 87 is connected to the support 85b via a matching box 86. The high-frequency power supply 87 may generate a high frequency having a frequency of 13.56MHz, for example.

When the plasma generator 80 having such a configuration supplies the high-frequency power from the high-frequency power supply 87 to the antenna 85 via the matching box 86, the antenna 85 generates a magnetic field. The electric field component in the magnetic field is shielded by the faraday shield 82 and therefore cannot propagate downward. On the other hand, the magnetic field component propagates into the 3 rd processing region P3 through the plurality of slits 82s of the faraday shield 82. The nitriding gas supplied from the reaction gas nozzle 33 to the 2 nd processing region P2 at a predetermined flow rate ratio is activated by the magnetic field component.

Next, the plasma generator 90 of the film deposition apparatus according to the present embodiment will be described.

Fig. 9 is a plan view of a film deposition apparatus according to an embodiment of the present invention, in which the plasma generators 80 and 90 are mounted. The plasma generator 90 is constructed as a remote plasma generating device.

The coupled Plasma generator (ICP, inductively coupled Plasma)80 using the antenna 85 described in fig. 6 to 8 is effective for generating Plasma at a high Plasma intensity, and functions effectively when both of an ionized nitriding gas and a radical-formed nitriding gas can be generated. However, a remote plasma generating device is suitable in the case where chlorine ions are not required, only chlorine radicals are required. That is, in the remote plasma generator, since the chlorine is activated by the plasma outside the vacuum chamber 1, ionized chlorine having a short lifetime is extinguished before reaching the inside of the vacuum chamber 1 or the wafer W, and only radical chlorine having a long lifetime is supplied to the wafer W. Accordingly, it is possible to supply the activated chlorine gas, in which the activated chlorine radicals account for a large part, to the wafer W as compared with the ICP plasma generator that directly generates plasma in the vacuum chamber 1. The plasma generator 90 of the present embodiment is a plasma generator capable of supplying chlorine radicals without substantially supplying ionized chlorine to the wafer W. A remote plasma generating device is an example of such a plasma generating device. The plasma generator 90 is not limited to a remote plasma generator, and various plasma generators can be used as long as chlorine ions are not generated so much and chlorine radicals are mainly generated.

Fig. 10 is a sectional view of the film deposition apparatus according to the present embodiment including the plasma generator 90.

As shown in fig. 10, the plasma generator 90 is provided in the 3 rd processing region P3 so as to face the turntable 2. The plasma generator 90 includes: a plasma generating part 91, a gas supply pipe 92, a shower head 93, and a pipe 94. The shower head 93 is an example of a chlorine gas discharge unit, and a gas nozzle may be used instead of the shower head 93.

The plasma generating section 91 activates the chlorine gas supplied from the gas supply pipe 92 by the plasma source. The plasma source is not particularly limited as long as it can generate radicals from chlorine gas. Examples of the Plasma source include Inductively Coupled Plasma (ICP), Capacitively Coupled Plasma (CCP), and Surface Wave Plasma (SWP).

The gas supply pipe 92 has one end connected to the plasma generation part 91, and supplies chlorine gas to the plasma generation part 91. The other end of the gas supply pipe 92 is connected to a chlorine gas supply source 132 in which chlorine gas is stored, for example, via an opening/closing valve and a flow rate regulator.

The shower head 93 is connected to the plasma generation unit 91 via a pipe 94, and supplies the fluorine-containing gas activated in the plasma generation unit 91 to the vacuum chamber 1. The shower head 93 has a fan-shaped planar shape and is pressed downward in the circumferential direction by a pressing member 95 formed along an outer edge of the fan-shaped planar shape. The pressing member 95 is fixed to the top plate 11 by a bolt or the like, not shown, so that the internal atmosphere of the vacuum chamber 1 is in an airtight state. The distance between the lower surface of the shower head 93 and the upper surface of the turntable 2 when fixed to the top plate 11 may be, for example, about 0.5mm to 5 mm.

The shower head 93 is provided with a plurality of gas discharge holes 93a so as to be reduced in the rotation center side and increased in the outer peripheral side in accordance with the angular velocity of the turntable 2. The number of the plurality of gas discharge holes 93a may be, for example, several tens to several hundreds. The diameters of the plurality of gas discharge holes 93a may be, for example, about 0.5mm to 3 mm. The activated chlorine gas supplied to the shower head 93 is supplied to the space between the turntable 2 and the shower head 93 through the gas discharge holes 93 a.

Fig. 11 is a plan view showing an example of the lower surface of the shower head 93. As shown in fig. 11, the lower projecting surface 93c may be formed in a band shape so as to extend along the outer periphery of the lower surface 93b of the fan-shaped shower head portion 93. Thereby, a decrease in pressure on the outer peripheral side of the 3 rd processing region P3 can be prevented uniformly in the circumferential direction. The gas discharge hole 93a may be provided at the circumferential center of the lower surface 93b of the shower head portion 93 so as to extend in the radial direction. This makes it possible to disperse and supply the chlorine gas from the center side to the outer peripheral side of the turntable 2.

In this manner, the chlorine radicals can be supplied to the wafer W using the plasma generator 90 configured as a remote plasma generating apparatus.

The remote plasma generator is not limited to the configuration having the shower head 93 shown in fig. 9 to 11, and may be configured to use the reaction gas nozzle 33 shown in fig. 2 and 3. In the above case, for example, the plasma generating portion 91 may be provided on the outer side surface of the container main body 12, and chlorine radicals may be supplied from the outer side surface side to the reaction gas nozzle 33.

As shown in fig. 1, the film deposition apparatus according to the present embodiment is provided with a control unit 100 configured by a computer for controlling the operation of the entire apparatus, and a program for causing the film deposition apparatus to perform a film deposition method to be described later under the control of the control unit 100 is stored in a memory of the control unit 100. This program is incorporated into a step group so as to execute a film forming method described later, is stored in a medium 102 such as a hard disk, an optical disk, a magneto-optical disk, a memory card, or a flexible disk, is read into a storage unit 101 by a predetermined reading device, and is installed in a control unit 100.

Further, the control unit 100 performs control for executing a film formation method according to an embodiment of the present invention described later.

[ film Forming method ]

Next, a case where the film forming method according to the embodiment of the present invention is performed by using the film forming apparatus will be described as an example with reference to fig. 12. Fig. 12 is a diagram illustrating a series of steps of an example of a film formation method according to an embodiment of the present invention.

The film forming method of the present embodiment can be used for forming various thin films, and in the present embodiment, dichlorosilane (DCS, SiH) is used for convenience of description₂Cl₂) An example of forming a silicon nitride film by using ammonia as a reaction gas and chlorine radicals as adsorption inhibiting radicals as a source gas is described.

Fig. 12 (a) is a diagram illustrating an example of a plasma reforming step in the film forming method according to the present embodiment.

In this embodiment, a silicon wafer is used as the wafer W. In fig. 12, for convenience of understanding, a description will be given of an example in which a silicon nitride film is formed on a flat surface of a wafer W without forming a pattern such as a recess such as a groove or a via on the surface of the wafer W. Hereinafter, a case will be described in which a silicon nitride film is formed on the flat surface of the wafer W.

As described above, in the present embodiment, dichlorosilane (DCS, SiH) is supplied from the reaction gas nozzle 31₂Cl₂) And nitrogen gas as a carrier gas, and ammonia (NH) as a nitriding gas supplied from the reaction gas nozzle 32₃) An example in which a mixed gas of argon and chlorine as a chlorine-containing gas is supplied from the shower head 93 will be described. However, since both the nitrogen gas as a carrier gas of dichlorosilane and the argon gas supplied together with the nitriding gas and the chlorine gas do not contribute to the reaction in the inert gas, they are not particularly mentioned in the following description. The nitriding gas is activated (converted into plasma) by ICP plasma generated in the plasma generator 80, and the chlorine-containing gas is supplied by converting the chlorine-containing gas into radicals by remote plasma generated in the plasma generator 90.

First, in the film deposition apparatus described with reference to fig. 1 to 11, a gate valve (not shown) is opened, and the wafer W is transferred from the outside by the transfer arm 10 (fig. 3) into the recess 24 of the turntable 2 through the transfer port 15 (fig. 2 and 3). This conveyance is performed by lifting and lowering a lift pin, not shown, from the bottom side of the vacuum chamber 1 through a through hole in the bottom surface of the recess 24 when the recess 24 stops at the position facing the transfer port 15. The turntable 2 is intermittently rotated to transfer the wafers W, and the wafers W are placed in the 5 recesses 24 of the turntable 2.

Next, the gate valve is closed, the vacuum pump 640 exhausts the inside of the vacuum chamber 1 to a vacuum degree that can be achieved, and then the separation gas nozzle 41 or 42 discharges the Ar gas as the separation gas at a predetermined flow rate, and the separation gas supply pipe 51 and the purge gas supply pipes 72 and 73 also discharge the Ar gas at a predetermined flow rate. Accordingly, the inside of the vacuum chamber 1 is controlled to a predetermined processing pressure by the pressure control means 650 (fig. 1). Subsequently, the wafer W is heated to, for example, 400 ℃ by the heater unit 7 while the turntable 2 is rotated clockwise at, for example, 10 rpm. The rotation speed of the turntable 2 can be set to various rotation speeds according to the application. In addition, the plasma generators 80 and 90 are also operated.

Thereafter, an adsorption site forming step is performed. Specifically, the activated nitriding gas is supplied from the reaction gas nozzle 32 (fig. 2 and 3), and the plasma modification of the surface of the wafer W is started. Thereby, the surface of the wafer W is modified by plasma nitridation, NH₂The radicals are adsorbed on the surface of the wafer W. Here, NH₂Since the radicals function as adsorption sites 140 for the raw material gas containing silicon, adsorption sites 140 for dichlorosilane as the raw material gas are formed on the surface of the wafer W. The first plasma modification step is as follows: the turntable 2 is rotated by a predetermined number of revolutions until the surface of the wafer W is sufficiently nitrided, and the supply of the nitriding gas is temporarily stopped after the post-modification stage is completed. The turntable 2 continues to rotate as it is with the wafer W placed thereon.

When the adsorption sites 140 for the source gas are already formed on the surface of the wafer W, the adsorption site forming step is not necessary. Even if the special adsorption sites 140 are not formed, the adsorption site forming step may not be provided when the source gas is in a state of being adsorbed on the surface of the wafer W. Thus, the adsorption site forming step can be provided as needed.

In the case where the adsorption site forming step of fig. 12 (a) is not performed, the turntable 2 may be rotated by supplying the separation gas, and then fig. 12 (b) may be performed without performing fig. 12 (a). After the plasma reforming step of fig. 12 (a) is performed for a predetermined time, the supply of the nitriding gas from the reaction gas nozzle 32 is stopped, and after the plasma reforming is temporarily stopped, the process proceeds to the step of fig. 12 (b). That is, when the process proceeds to the step (b) of fig. 12, both when the plasma reforming step is performed and when the plasma reforming step is not performed, the supply of the nitriding gas from the reaction gas nozzle 32 is stopped.

Fig. 12 (b) is a diagram illustrating an example of the step of preventing the formation of the suction region. In the present embodiment, the adsorption-impeding region forming step is a step of adsorbing chlorine radicals, which are adsorption-impeding radicals, on the surface of the wafer W, more precisely, on the surfaces of the adsorption sites 140, and therefore, may be referred to as an adsorption-impeding radical adsorbing step or, more specifically, a chlorine radical adsorbing step.

As described above, the adsorption-impeding region forming step is performed in a state where the supply of the activated nitriding gas is stopped. In the adsorption-impeding region forming step, the turntable 2 is rotated by a predetermined number of revolutions in a state where chlorine radicals are supplied from the shower head 93, and the chlorine radicals are adsorbed discretely or dispersedly on the surface of the wafer W. That is, the chlorine radicals are not adsorbed on the entire surface of the wafer W, but the chlorine radicals are dispersedly adsorbed on the adsorption sites 140 while leaving the adsorption sites 140 to some extent. Thus, NH as an adsorption site 140₂The radicals are also present discretely or dispersedly on the surface of the wafer W. That is, the adsorption sites 140 are partially or partially covered by the adsorption of chlorine radicals, but the regions not adsorbing chlorine radicals are also partially or partially left, and thus the adsorption sites 140 are exposed dispersedly or discretely.

In the adsorption region formation inhibiting step, although argon gas as the separation gas is supplied from the separation gas nozzles 41 and 42, the supply of dichlorosilane as the raw material gas from the reaction gas nozzle 31 and the supply of ammonia as the nitriding gas from the reaction gas nozzle 32 may be maintained.

The chlorine radical has an effect of inhibiting adsorption of dichlorosilane containing chlorine, and thus adsorption of dichlorosilane is suppressed. In the adsorption-hindering region forming step, a predetermined amount of the adsorption-hindering radicals having such an adsorption-hindering effect are discretely adsorbed on the adsorption sites 140, and the adsorption-hindering regions 150 are discretely formed on the adsorption sites 140. That is, the chlorine radicals are partially or partially adsorbed on the adsorption sites 140 on the surface of the wafer W, covering the adsorption sites 140, and the adsorption sites 140 are partially or partially exposed.

The formation of such a discrete adsorption-hampering region 150 is performed by adjusting the supply time or flow rate of the chlorine gas as the adsorption-hampering gas. In the case of the film forming apparatus of the present embodiment, the time of the chlorine radical adsorption step can be easily adjusted by adjusting how many times the turntable 2 is rotated to continue the chlorine radical adsorption step. That is, if the number of revolutions of the turntable 2 on which the chlorine radical adsorption step is continuously performed is set to be large, the chlorine radicals are adsorbed on a wide area of the adsorption sites 140, which prevents the adsorption area from being formed in a wide range, and if the number of revolutions of the turntable 2 is reduced, the adsorption range of the chlorine radicals is narrowed, and the adsorption sites 140 are left in a wide range. Further, if the supply amount of chlorine radicals per unit time is increased, a large amount of chlorine radicals can be adsorbed, and therefore, the distribution and width of the inhibition adsorption region 150 can also be adjusted by the supply amount of chlorine gas.

In any case, the adsorption obstructing regions 150 are not formed over the entire adsorption sites 140, but the adsorption obstructing regions 150 are formed discretely or dispersedly. This makes it possible to control the amount of adsorption of the raw material gas.

The adsorption of chlorine radicals is physical adsorption, and is adsorption utilizing coulomb force having high electronegativity derived from chlorine. Thus, unlike chemical bonding, there is a horizontal level of adsorption that will simply blow away.

Fig. 12 (c) is a diagram showing an example of the raw material gas adsorption step. In the raw material gas adsorption step, a raw material gas 160 containing silicon and chlorine is supplied to the surface of the wafer W. That is, dichlorosilane is supplied from the reaction gas nozzle 31. Thus, dichlorosilane as the raw material gas 160 is adsorbed on the surfaces of the adsorption sites 140 on the wafer W. At this time, since the adsorption-impeding regions 150 are discretely formed, dichlorosilane as the raw material gas 160 is discretely adsorbed on the adsorption sites 140 discretely exposed without forming the adsorption-impeding regions 150.

In this way, the amount of adsorption of the raw material gas can be controlled by controlling the amount of adsorption in the adsorption-hampering region 150.

Fig. 12 (d) is a diagram showing an example of the reaction product deposition step. In the reaction product deposition step, the reaction gas 170 is supplied to the surface of the wafer W on which the raw material gas is discretely adsorbed in a predetermined adsorption amount, and the reaction product 180 of the raw material gas 160 and the reaction gas 170 is deposited on the surface of the wafer W. In the present embodiment, ammonia as a nitriding gas is supplied to the surface of the wafer W on which dichlorosilane is dispersedly adsorbed, and silicon nitride as a reaction product 180 is deposited on the wafer W to form a silicon nitride film. Thus, in this embodiment, the reaction product deposition step is also referred to as a nitriding step. More specifically, the nitriding gas is supplied from the reaction gas nozzle 32, and the nitriding gas (ammonia) activated by the plasma generator 80 is supplied to the surface of the wafer W. The activated ammonia reacts with dichlorosilane and a molecular layer of silicon nitride as reaction product 180 is deposited on the surface of wafer W. Since dichlorosilane is discretely adsorbed on the surface of the wafer W, the adsorbed dichlorosilane is sparsely adsorbed on the wafer W, and ammonia easily contacts the entire surface of dichlorosilane, so that dichlorosilane can be sufficiently nitrided, and a dense silicon nitride film can be formed.

As described above, for example, when the activated reaction gas 170 is supplied in a case where adsorption of adsorption radicals such as chlorine radicals onto the adsorption sites 140 is prevented, the adsorption radicals are blown off, and most or all of the adsorption prevention regions 150 are eliminated.

In order to perform film formation by ALD (Atomic Layer Deposition), it is necessary to adsorb the source gas 160 on the surface of the wafer W (more precisely, the surface of the adsorption sites 140) and then supply a reaction gas such as a nitriding gas to deposit a thin film of the reaction product 180, but in order to improve the quality (membranous) of the thin film, it is necessary to sufficiently react the source gas 160 with the reaction gas 170 to deposit a dense (high-density) thin film.

In order to improve the film quality of the deposited thin film, the activated reaction gas 170 is supplied to the source gas 160 adsorbed on the surface of the wafer W, and a reforming treatment for improving the film quality is frequently performed. The activated reaction gas 170 is generated by, for example, plasma-activating the reaction gas 170. In the case of the present embodiment, the plasma generator 80 activates and supplies ammonia as the nitriding gas. Thereby, a nitriding plasma and a nitriding radical are generated.

The reforming step may be performed independently of the reaction product deposition step, but in the present embodiment, a film formation method is exemplified in which the reaction product deposition step uses the plasma-generated activated reaction gas 170, and both the deposition of the reactant and the reforming are performed.

That is, at the time of nitriding the source gas 160 or after nitriding the source gas 160, the modification step is performed by supplying the plasma-activated reaction gas (nitriding gas) 170 to the wafer W. Here, when the raw material gas 160 is adsorbed on the entire surface of the wafer W, the activated reaction gas 170 merely causes the surface plasma nitridation of the raw material gas 160, and even if the modification step is performed for a long time, the nitridation does not progress, and sufficient modification may not be performed. This is considered because the source gas 160 is adsorbed on the surface of the wafer W in a saturated state, and thus the nitriding radicals do not reach the deep part of the source gas 160, and the amount of nitriding is limited.

Fig. 13 is a diagram for explaining a film formation method of a comparative example. That is, the problem when nitriding the source gas saturated and adsorbed on the surface of the wafer W will be described.

Fig. 13 (a) shows a state in which dichlorosilane 161 as a source gas is adsorbed on the surface of the wafer W in a saturated state. In this case, the molecules of dichlorosilane 161 as the source gas are closely adsorbed on the surface of the wafer W, and there is substantially no gap between adjacent molecules of dichlorosilane 161.

Fig. 13 (b) is a diagram showing a case where activated ammonia 171 (ammonia plasma and/or ammonia radicals) as a reaction gas is supplied to the saturated and adsorbed dichlorosilane 161. Since the dichlorosilane 161 is densely arranged, the activated ammonia 171 as the reaction gas can be adsorbed only on the upper surface of the dichlorosilane 161. Thus, all of the dichlorosilane 161 is not nitrided by the activated ammonia 171. Even if the activated ammonia 171 is supplied for a long time in this state, the reactive surface is only the upper surface of the densely adsorbed dichlorosilane 161, and thus the nitridation of the dichlorosilane 161 cannot be sufficiently advanced. That is, the nitriding is saturated.

Fig. 14 is a diagram for explaining the film formation method according to the present embodiment. That is, the reaction product of the source gas controlled to a predetermined adsorption amount is generated on the surface of the wafer W.

Fig. 14 (a) is a diagram showing a state in which the chlorine radicals 151 are adsorbed between the dichlorosilane 161 thereof. That is, chlorine radicals 151 are discretely adsorbed on the adsorption sites 140 (fig. 12), and dichlorosilane 161 as a raw material gas is discretely adsorbed on a region where the chlorine radicals 151 are not adsorbed.

Fig. 14 (b) is a view showing a state in which nitrogen radicals are supplied to the surface of the wafer W on which dichlorosilane 161 is discretely adsorbed by chlorine radicals 151 which are inhibition radicals from adsorbing, and a silicon nitride film 181 is deposited. As shown in fig. 14 (b), since the dichlorosilane 161 is discretely adsorbed, the activated ammonia 171 can be adsorbed not only on the upper surface but also on the side surface of the dichlorosilane 161, and can sufficiently react with the dichlorosilane 161. As described above, since the chlorine radicals 151 are adsorbed on the adsorption sites 140 by physical adsorption, a corresponding portion of the chlorine radicals 151 is blown off by the supply of the activated ammonia 171, and the exposed surface of the dichlorosilane 161 is increased. Thus, the activated ammonia can be adsorbed not only on the upper surface but also on the side surface of the discretely adsorbed dichlorosilane 161, and can be reacted to the depth of the dichlorosilane 161. This advances the nitridation of the dichlorosilane 161, thereby growing and depositing a dense silicon nitride film 181 having a high density, that is, a high-quality silicon nitride film 181.

In this way, the chlorine radicals 151 functioning as the adsorption inhibiting radicals are discretely adsorbed on the adsorption sites 140 to discretely form the adsorption inhibiting regions 150, and then the adsorption amount of dichlorosilane 161 serving as the supplied source gas 160 is controlled to supply activated ammonia 171 serving as the reaction gas 170, so that the chlorine radicals 151 are blown off and reacted with the dichlorosilane 161, thereby forming the dense silicon nitride film 181. This enables film formation with controlled film quality and control of film density of the deposited thin film.

The interval between the dichlorosilane 161 molecules is determined by the deposition rate, i.e., the cycle rate, for 1 cycle, i.e., 1 time of adsorption of dichlorosilane 161 and 1 time of nitridation. Thus, by controlling the circulation rate, the interval between the molecules of the dichlorosilane 161 can be controlled, and the film quality can be controlled.

Returning to the description of fig. 12.

In the raw material gas adsorption step and the reaction product deposition step in fig. 12 (c) and (d), the supply of the raw material gas from the reaction gas nozzle 31 and the supply of the nitriding gas from the reaction gas nozzle 32 may be started simultaneously. This is because, as shown in fig. 2, 3, and 9, if the turntable 2 is rotated clockwise, the wafer W passes through the chlorine radical supply region P3, reaches the source gas supply region P1, and then reaches the nitriding gas supply region P2, and therefore, even if the supply of the source gas and the nitriding gas is started at the same time, the nitriding step is performed after the source gas adsorption step.

In addition, between the raw material gas adsorption step and the reaction product deposition step shown in fig. 12 (c) and (d), the supply of the adsorption matrix radicals may be stopped or not stopped, and is preferably not stopped from the viewpoint of smoothly proceeding to the next step of inhibiting the formation of the adsorption region. The chlorine radical adsorption step shown in fig. 12 (b) is performed by rotating the turntable 2 at least 1 time for a predetermined time, while the raw material gas adsorption step and the nitriding step shown in fig. 12 (c) and (d) are performed by rotating the turntable 2 only 1 time. That is, in the arrangement shown in fig. 2, 3, and 9, after chlorine radicals are supplied to the wafer W on the turntable 2 in the 3 rd processing region P3, the source gas is supplied to the 1 st processing region P1, the source gas adsorbed on the surface of the wafer W is nitrided in the 2 nd processing region P2, a molecular layer of the SiN film is deposited on the wafer W, and then the wafer W immediately enters the 3 rd processing region P3, and chlorine radicals are supplied. Thus, the sequence of (b) to (d) in fig. 12 can be continuously performed without stopping the supply of the chlorine radicals.

The reaction product deposition step (or nitriding step) in fig. 12 (d) may be extended, but it is preferable to control the amount of adsorption of the source gas 160 so that sufficient nitriding can be achieved even by rotating the turntable 2 only 1 time. That is, by reducing the adsorption amount of the source gas 160, nitriding with 1 rotation can be performed with a sufficient film density.

In the raw material gas adsorption step and the nitriding step in fig. 12 (c) and (d), the raw material gas 160 is nitrided to be NH₂The hydrogen radicals of the structure terminate, forming adsorption sites 140 for the feed gas 160. Then, in the adsorption-hindering region forming step of fig. 12 (b), when chlorine radicals, which are adsorption-hindering radicals, are supplied, NH is generated₂The H group of the structure is replaced by a Cl group. As described above, since dichlorosilane is a gas containing chlorine and chlorine does not adsorb to each other, the raw material gas 160 is not adsorbed to the site terminated with chlorine. In this way, the site terminated with Cl groups functions as an adsorption-inhibiting group, and inhibits adsorption of the raw material gas 160. Thus, the Cl groups are discretely adsorbed on the surface of the wafer W, whereby the adsorption amount of the raw material gas 160 can be controlled.

In the present embodiment, the adsorption inhibiting radicals are chlorine radicals and the raw material gas 160 is dichlorosilane containing chlorine and silicon, but the raw material gas 160 and the adsorption inhibiting radicals may be in various combinations as long as the combination can form the adsorption inhibiting region 150 in the raw material gas 160. The method of inhibiting adsorption is not limited to the method using electronegativity, and any principle or method may be used as long as the adsorption of the raw material gas 160 is inhibited by the ability to inhibit adsorption of radicals.

By repeating the steps (b) to (d) in fig. 12 in this manner, dense and high-quality reaction product 180 is gradually deposited on the surface of wafer W. The deposition rate may be slightly lower than that of the usual film formation under the influence of chlorine radicals which inhibit adsorption groups, but the film can be formed into a high-quality thin film in which plasma modification is sufficiently performed without performing a separate modification step, and as a result, the high-quality film formation can be performed without lowering the throughput.

Fig. 12 (e) is a diagram showing an example of a plasma reforming step performed as necessary. As described above, the amount of adsorption of the raw material gas 160 is controlled, whereby high-quality film formation can be performed without performing a separate plasma reforming step, but depending on the required process, when it is not possible to sufficiently reduce the amount of adsorption of the raw material gas 160 and it is desirable to use a single plasma reforming step in combination, a single plasma reforming step may be performed as necessary.

In the plasma reforming step (e) of fig. 12, the SiN film is plasma-reformed by supplying the nitriding gas activated by the plasma generator 80 from the reaction gas nozzle 32 to the SiN film. This step is the same operation as the plasma reforming step performed in fig. 12 (a), but differs from the plasma reforming step in fig. 12 (a) in that the step is performed for the purpose of reforming a deposited silicon nitride film. When the nitridation of the silicon nitride film is insufficient after rotating the turntable 21 time, the plasma-activated nitridation gas is supplied with the supply of the source gas 160 stopped, so that the silicon nitride film is sufficiently nitrided, and a high-density, dense and high-quality silicon nitride film can be formed. The plasma reforming step is performed in a state where only the nitriding gas and the separation gas activated by plasma are supplied, and the raw material gas and the chlorine radicals are not supplied. In the plasma modification step, the surface of the wafer W is modified by plasma nitridation.

The plasma reforming step is not essential as long as it is performed as necessary, as in the plasma reforming step (a) of fig. 12. The selective step is performed only when necessary, in the case where a special requirement such as high-quality film formation is required without reducing the amount of adsorption of the source gas 160 too much.

After the film formation is completed, the supply of all the gases and the plasma generators 80 and 90 are stopped, and the rotation of the turntable 2 is stopped. Then, the turntable 2 is intermittently rotated and stopped in reverse order to the time of loading the wafer W, the wafer W is lifted by the lift pins, and the wafers W are sequentially unloaded from the vacuum chamber 1. A high-quality silicon nitride film is formed on the surface of the wafer W in a conformal manner.

As described above, according to the film formation method of the present embodiment, a high-quality silicon nitride film can be formed on the surface of the wafer W. In fig. 12, an example of forming a silicon nitride film on the flat surface of the wafer W is described, but high-quality film formation can be performed for various pattern shapes including recessed patterns such as trenches and via holes regardless of the shape of the surface of the wafer W. In a variety of semiconductor manufacturing processes, there are many demands for high-quality film formation in various patterns such as trenches and vias, and the film formation method and film formation apparatus of the present embodiment and the demand for high-quality film formation can be met, and thus the present invention can be used in various applications.

In addition, although the present embodiment has been described by taking an example in which the film forming method of the present embodiment is applied to ALD film formation using a rotary-table-type ALD film forming apparatus, a film forming method in which the adsorption inhibiting region 150 is formed discretely on the adsorption inhibiting sites 140 for inhibiting adsorption of the radicals by a predetermined amount and the adsorption amount of the raw material gas 160 is controlled can be used for CVD (Chemical Vapor Deposition) or an ALD film forming apparatus or a CVD film forming apparatus other than the rotary-table-type ALD film forming apparatus. In the CVD film formation, the steps (c) and (d) in fig. 12 are performed simultaneously, and this is because if the adsorption inhibiting regions 150 are formed in a dispersed manner in advance, the amount of adsorption of the source gas 160 can be controlled.

From the above-described viewpoint, the film deposition method of the present embodiment can be applied to a single wafer processing type (japanese sample type) CVD film deposition apparatus, an ALD film deposition apparatus, a vertical heat treatment apparatus that carries a plurality of wafers W into a processing container, supplies a gas into the processing container, and performs a heat treatment, and the like.

That is, in the adsorption-impeding region forming step of fig. 12 (b), the adsorption-impeding regions 150 are formed in a dispersed manner, and then ALD or CVD film formation is performed, so that the adsorption amount of the source gas can be controlled, and film quality can be controlled and high-quality film formation can be performed.

As described above, the thin film to be formed can be used in a process for forming various thin films by dispersedly forming the adsorption inhibiting regions 150 with respect to the source gas 160 in a state where the adsorption sites 140 with respect to the source gas 160 are formed and controlling the adsorption amount of the source gas 160.