阅读说明：本技术 一种离子源挡片、离子刻蚀机及其使用方法 (Ion source baffle plate, ion etching machine and using method thereof ) 是由 张瑶瑶 胡冬冬 刘海洋 张军 李娜 程实然 朱治友 许开东 于 2020-05-22 设计创作，主要内容包括：本发明提出了一种离子源挡片、离子刻蚀机及其使用方法,该离子源挡片包括挡片本体；挡片本体为一中空结构；挡片本体的内壁上固定对称设置的挡片；挡片朝挡片本体的中心方向延伸；沿挡片本体的内壁朝挡片本体中心的方向,挡片形成的遮挡区域由大变小；离子刻蚀机包括放电室、反应室和离子源挡片,离子源挡片卡设在放电室的内壁上；等离子体依次经过离子源挡片和离子源Grid组件。本发明的离子刻蚀机通过增设一离子源挡片,等离子体经离子源挡片进行遮挡后,自放电室的边缘区域至放电室的中心区域,等离子体的数量逐渐增多,从而补偿了屏栅上外小孔大于内小孔的结构设计,保证了等离子体穿过屏栅形成的等离子束的均匀性。(The invention provides an ion source baffle plate, an ion etching machine and a using method thereof, wherein the ion source baffle plate comprises a baffle plate body; the baffle plate body is of a hollow structure; the inner wall of the baffle plate body is fixedly provided with baffle plates which are symmetrically arranged; the baffle sheet extends towards the center direction of the baffle sheet body; the shielding area formed by the baffle plate is reduced from large to small along the direction from the inner wall of the baffle plate body to the center of the baffle plate body; the ion etching machine comprises a discharge chamber, a reaction chamber and an ion source baffle plate, wherein the ion source baffle plate is clamped on the inner wall of the discharge chamber; the plasma sequentially passes through the ion source baffle plate and the ion source Grid assembly. According to the ion etching machine, the ion source blocking piece is additionally arranged, and after the plasma is blocked by the ion source blocking piece, the number of the plasma is gradually increased from the edge area of the discharge chamber to the central area of the discharge chamber, so that the structural design that the outer small hole is larger than the inner small hole on the screen grid is compensated, and the uniformity of the plasma beam formed by the plasma penetrating through the screen grid is ensured.)

1. An ion source baffle plate is characterized by comprising a baffle plate body; the baffle plate body is of a hollow structure; the inner wall of the baffle plate body is fixedly provided with baffle plates which are symmetrically arranged; the baffle plate extends towards the center direction of the baffle plate body; the inner wall of the separation blade body faces the direction of the center of the separation blade body, and a shielding area formed by the separation blade is reduced from large to small.

2. The ion source baffle of claim 1, wherein the baffle body is annular.

3. The ion source baffle of claim 1, wherein the inner section of the baffle is polygonal or circular.

4. The ion source baffle of claim 1 wherein the baffle is fan-shaped.

5. The ion source baffle of claim 4 wherein the fan shape corresponds to a fan central angle of 3 ° to 15 °.

6. The ion source baffle of claim 1, wherein the material of the baffle is a quartz material or a ceramic material.

7. An ion etcher based on the ion source baffle of any one of claims 1 to 6, comprising a discharge chamber and a reaction chamber;

the reaction chamber comprises a connecting cavity and a reaction cavity communicated with the connecting cavity;

the discharge chamber is positioned in the connecting cavity and communicated with the reaction cavity;

an ion source Grid component which focuses plasma to form plasma beams is arranged in the connecting cavity; the ion source Grid component is close to one side of the discharge chamber communicated with the reaction cavity;

the ion source Grid component comprises a screen Grid; the screen grid is provided with inner small holes and outer small holes; the diameter of the inner small hole is smaller than that of the outer small hole;

the ion source baffle plate is clamped on the inner wall of the discharge chamber; the plasma sequentially passes through the ion source baffle plate and the ion source Grid assembly.

8. The ion etcher of claim 7, wherein the distance between the ion source baffle and the ion source Grid assembly is greater than zero.

9. The use method of the ion etcher based on claim 7 is characterized by comprising the following steps:

(1) clamping the ion source baffle plate at one side of the discharge chamber close to the ion source Grid assembly;

(2) generating the plasma in the discharge chamber;

(3) after the plasmas are shielded by the ion source baffle plate, the number of the plasmas is gradually increased from the edge area of the discharge chamber to the central area of the discharge chamber;

(4) and the plasma is emitted into a screen Grid of the ion source Grid component and then sequentially penetrates through the screen Grid to form a plasma beam, and the plasma beam penetrates through an acceleration Grid of the Grid component and is emitted into the reaction cavity.

Technical Field

The invention belongs to the field of machining equipment, and particularly relates to an ion source baffle, an ion etching machine and a using method of the ion source baffle.

Background

The ion source is a key component of ion beam etching, and the quality of the ion source directly influences the etching performance. The specific process of ion beam etching is as follows: in radio frequency ion sources, e.g. Ar, O₂The plasma gas enters the quartz discharge chamber through a specially designed gas voltage-sharing insulator, and high-frequency waves initiated by an RF coil are used for mixing electrons and positive ions in the plasma gas to form plasma, and the plasma is transmitted to a target substrate in the form of ion beams through a Grid component to etch the surface of the target substrate (wafer). The ion source Grid component generally comprises a screen Grid, an acceleration Grid and a deceleration Grid (some grids do not have the deceleration Grid), and a tri-Grid system is adopted, so that the ion source has better performance under low-energy flow, the beam divergence angle is relatively small, and the pollution from the Grid can be reduced. The screen grid as an anode in the discharge chamber can absorb discharge electrons to form a discharge loop to play a role in focusing; the acceleration grid can extract positive ions, and the deceleration grid can effectively adjust the ion distribution.

In the prior art, when gas is ionized in a discharge chamber, the plasma density is continuously reduced from a central area to an edge area along a radial direction, and in order to ensure the etching uniformity of a target substrate, the size of small holes on a screen grid needs to be gradually increased from the central area to the edge area along the radial direction so as to ensure the etching uniformity of an ion source, as shown in fig. 1(a) to 1(c), wherein r1 to r4 (coordinate X) is the distance from the area where the small holes on the screen grid are located to the center of the screen grid; phi is a₁~φ₄(coordinate Y) is the diameter of the small hole on the grid; the etching speed of the edge region is high, so that the etching of the whole target substrate is not uniform, see FIG. 2 (C)a) And 2(b), the etching speed of the edge region of the target substrate is fastest.

Disclosure of Invention

The invention aims to provide an ion source baffle plate, an ion etching machine and a using method thereof, wherein the ion etching machine is additionally provided with the ion source baffle plate, plasma generated in a discharge chamber sequentially passes through the ion source baffle plate, a screen grid and an accelerating grid, the number of the plasma is gradually increased from the edge area of the discharge chamber to the central area of the discharge chamber after the plasma is shielded by the ion source baffle plate, and the density of the plasma at the edge area of the discharge chamber is reduced relative to the central area of the discharge chamber, so that the structural design that an outer pore on the screen grid is larger than an inner pore is compensated, and the uniformity of the plasma beam formed by the plasma passing through the screen grid is ensured. In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides an ion source baffle plate, which comprises a baffle plate body; the baffle plate body is of a hollow structure; the inner wall of the baffle plate body is fixedly provided with baffle plates which are symmetrically arranged; the baffle plate extends towards the center direction of the baffle plate body; the inner wall of the separation blade body faces the direction of the center of the separation blade body, and a shielding area formed by the separation blade is reduced from large to small.

Preferably, the flap body is annular.

Preferably, the inner section of the baffle plate is polygonal or circular.

Preferably, the baffle is in the shape of a sector.

Preferably, the central angle of the sector corresponding to the sector is 3-15 degrees.

Preferably, the material of the baffle plate is quartz material or ceramic material.

The invention also provides an ion etching machine, which is based on the ion source baffle plate and comprises a discharge chamber and a reaction chamber;

the reaction chamber comprises a connecting cavity and a reaction cavity communicated with the connecting cavity;

the discharge chamber is positioned in the connecting cavity and communicated with the reaction cavity;

an ion source Grid component which focuses plasma to form plasma beams is arranged in the connecting cavity; the ion source Grid component is close to one side of the discharge chamber communicated with the reaction cavity;

the ion source Grid component comprises a screen Grid; the screen grid is provided with inner small holes and outer small holes; the diameter of the inner small hole is smaller than that of the outer small hole;

the ion source baffle is clamped on the inner wall of the discharge chamber; the plasma sequentially passes through the ion source baffle plate and the ion source Grid assembly.

Preferably, the distance between the ion source baffle and the ion source Grid assembly is greater than 3 mm.

The invention also provides a using method of the ion etching machine, and the method comprises the following steps based on the ion etching machine:

(1) clamping the ion source baffle plate at one side of the discharge chamber close to the ion source Grid assembly;

(2) generating the plasma in the discharge chamber;

(3) after the plasmas are shielded by the ion source baffle plate, the number of the plasmas is gradually increased from the edge area of the discharge chamber to the central area of the discharge chamber;

(4) and the plasma is emitted into a screen Grid of the ion source Grid component and then sequentially penetrates through the screen Grid to form a plasma beam, and the plasma beam penetrates through an acceleration Grid of the Grid component and is emitted into the reaction cavity.

Compared with the prior art, the invention has the advantages that:

(1) the shielding area formed by the baffle plate is gradually reduced along the direction of the inner wall of the baffle plate body pointing to the center of the baffle plate body, so that plasma blocked by the edge area of the baffle plate body is more than plasma blocked by the center area of the baffle plate body, after the plasma is shielded by the baffle plate, the number of the plasma is gradually increased from the edge area of the discharge chamber to the center area of the discharge chamber under the action of the baffle plate, namely, the plasma density of the edge area of the discharge chamber is reduced relative to the center area of the discharge chamber.

(2) The ion etcher is additionally provided with an ion source baffle, plasmas generated in the discharge chamber sequentially pass through the ion source baffle, the screen Grid and the acceleration Grid, the plasmas are gradually increased from the edge area of the discharge chamber to the central area of the discharge chamber after being shielded by the ion source baffle, and the density of the plasmas at the edge area of the discharge chamber is reduced relative to the central area of the discharge chamber, so that the structural design that the outer small holes on the screen Grid are larger than the inner small holes is compensated, the plasmas form plasma beams which tend to be uniformly distributed after passing through the screen Grid and the acceleration Grid, and the uniformity of the plasma beams formed by the plasmas penetrating through the Grid assembly of the ion source is ensured.

Drawings

FIG. 1(a) is a top view of a prior art screen grid;

FIG. 1(b) is a partial schematic view of an inner aperture in the screen of FIG. 1 (a);

FIG. 1(c) is a schematic diagram showing the change in the diameter of the inner and outer apertures of the screen in FIG. 1 (a);

FIGS. 2(a) to (b) are graphs showing the etching rate distribution of a target substrate in the prior art;

fig. 3(a) is a structural diagram of an ion source baffle according to a first embodiment of the present invention;

FIGS. 3(b) - (e) are structural diagrams of ion source baffles according to other embodiments of the present invention;

FIG. 4(a) is a schematic view of an ion etcher according to a first embodiment of the present invention;

FIG. 4(b) is a partial schematic view of FIG. 4 (a);

FIG. 4(c) is a side view of FIG. 4 (b);

FIGS. 4(d) to 4(e) are schematic views illustrating the installation of ion source baffles in an ion etcher according to other embodiments of the present invention;

fig. 5 is a schematic inner diameter view of an ion source baffle plate according to a first embodiment of the present invention.

The ion source device comprises an ion source baffle plate 1, an ion source baffle plate 11, a baffle plate body 12, a discharge chamber 2, a reaction chamber 3, a connecting cavity 31, a reaction cavity 32, an ion source Grid component 4, a screen Grid 41, an accelerating Grid 42, an outer aperture 411 and a target substrate 5.

Detailed Description

The present invention will now be described in more detail with reference to the accompanying schematic drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art may modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

As shown in fig. 3(a), an ion source baffle 1 includes a baffle body 11; the baffle plate body 11 is a hollow structure; the inner wall of the baffle plate body 11 is fixedly provided with baffle plates 12 which are symmetrically arranged, and the baffle plates 12 extend towards the center direction of the baffle plate body 11; the shielding area formed by the baffle 12 gradually becomes smaller along the direction from the inner wall of the baffle body 11 to the center of the baffle body 11. Preferably, the flap body 11 is annular. The baffle plate 12 can also be a structure with a large middle part and small two ends.

In the present embodiment, the blocking plate 12 is horizontally disposed, and the blocking area formed by the blocking plate 12 refers to a portion blocked by the width area of the blocking plate 12. The width of the baffle plate 12 decreases linearly from the edge region to the central region, so that the edge region blocks more plasma than the central region. As can be known by those skilled in the art, the edge areas of the three members of the barrier plate body 11, the barrier plate 12, and the discharge chamber 2 are the same, and the central areas of the three members are also the same.

In the present embodiment, the baffle 12 has a fan shape. According to the difference of the etching speed of the edge area and the etching speed of the central area, the central angle of the sector corresponding to the sector is 3-15 degrees. When the etching speed of the edge area is slightly higher than that of the central area, the central angle corresponding to the fan shape can be selected to be 3 degrees, and when the etching speed of the edge area is obviously higher than that of the central area, the central angle corresponding to the fan shape is gradually increased to meet the requirement of etching uniformity.

Preferably, for the convenience of processing, the thicknesses of the baffle plate body 11 and the baffle plates 12 are selected to be between 3mm and 6mm, and the circumference of the part of the baffle plate body 11 between the adjacent baffle plates 12 is 8mm to 15 mm. The material of the baffle plate 12 is quartz material or ceramic material.

As shown in fig. 3(a), the number of the flaps 12 is 6; in other embodiments, as shown in fig. 3(b), the number of flaps 12 is 2.

In other embodiments, as shown in fig. 3(c) - (d), the inner sections of the baffle 12 are polygonal and circular. From the aspect of process effect, when the region with faster etching is located between the radii r 1-r 4, as shown in fig. 1(b), the plasma density in the central region needs to be reduced to ensure uniform plasma distribution in the whole etching process, and then the baffle plate 12 can also be in the shape of a parallelogram or an ellipse with a large middle part and a small outer end.

Taking the parallelogram as an example, when the etching speed of the etching region between the radii r 2-r 3 is significantly higher than that of other regions, the plasma density of the region needs to be reduced, and then the baffle plate 12 should shield more plasma between the radii r 2-r 3. According to the difference of the etching rate, the size of the barrier sheet 12 formed by the parallelogram can be changed according to the process test structure.

The embodiment further provides an ion etcher, as shown in fig. 4(a) to 4(c), based on the ion source baffle 1, on the basis of the existing ion etcher, an ion source baffle 1 is additionally provided to form an improved ion etcher, the improved ion etcher mainly includes three parts, namely a discharge chamber 2, a reaction chamber 3 and an ion source baffle 1, and the specific structure is as follows:

the reaction chamber 3 comprises a connecting cavity 31 and a reaction cavity 32 communicated with the connecting cavity 31; the discharge chamber 2 is located in the connection cavity 31 and communicated with the reaction cavity 32.

An ion source Grid component 4 which focuses plasma to form a plasma beam is arranged in the connecting cavity 31; the ion source Grid assembly 4 is close to one side of the discharge chamber 2 communicated with the reaction cavity 32.

The ion source Grid assembly 4 includes a screen 41; the screen 41 is provided with an inner small hole and an outer small hole 411; the diameter of the inner aperture is smaller than the diameter of the outer aperture 411; the ion source Grid assembly 4 is a prior art, and the screen 41 in the ion source Grid assembly 4 has the same structure as the screen 41 in fig. 1 (a).

The ion source baffle plate 1 is clamped on the inner wall of the discharge chamber 2; the plasma passes through the ion source baffle plate 1 and the ion source Grid assembly 4 in sequence.

In this embodiment, the distance between the ion source baffle 1 and the ion source Grid assembly 4 is greater than zero.

Since the aperture size of the small holes from the center to the edge on the screen 41 increases in a piecewise function manner, as shown in fig. 1(b), assuming that the variation is N segments, in the process, according to the area with fast edge etching speed, as shown in fig. 5, the inner diameter phi of the baffle 1 is preferably between R/N to (N-1) R/N (R is the inner diameter of the discharge chamber 2), and when the edge speed is obviously superior to other areas, the fan-shaped inner diameter should be (N-1) R/N, so as to avoid that the shielding area of the fan-shaped baffle 12 is large and the etching speed of the central area is affected; when the area with the higher edge etching speed is increased, the inner diameter of the fan-shaped ion source baffle plate 1 is reduced continuously to increase the shielding area. The fan-shaped ion source may be single-segment or multi-segment, wherein the multi-segment can avoid multiple processes, and the length of the fan-shaped baffle 12 can be adjusted at any time according to experimental data, as shown in fig. 3(e), in other embodiments, the ion source is a multi-segment structure.

In order to effectively adjust the plasma density in the edge area of the discharge chamber 2 and to make the plasma density distribution in the edge area and the center area of the target substrate 5 uniform, the number of the baffle plates 12 of the ion source baffle plate 1 can be preferably 2-20, and for different etching speeds of the ion etcher, the number of the baffle plates 12 in the ion source baffle plate 1 and each ion source baffle plate 1 refers to the following working conditions:

(1) when the etching speed of the edge area of the target substrate 5 is changed less than that of the central area of the target substrate 5, one ion source baffle plate 1 with only 2 baffle plates 12 can be independently arranged for installation; as shown in FIG. 3 (b);

(2) as the difference between the etching rates of the edge region of the target substrate 5 and the core region of the target substrate 5 increases, the number of the baffles 12 may gradually increase to 6, as shown in fig. 3(a) and 4 (d);

(3) when the difference between the etching rates of the edge region of the target substrate 5 and the central region of the target substrate 5 continues to increase, the ion source masks 1 may be installed in groups. If the etching rate of the edge region of the target substrate 5 is significantly higher than that of the central region of the target substrate 5 and a single ion source baffle 1 cannot meet the requirement, two or more ion source baffles 1 are required to be installed to ensure the etching uniformity of the target substrate 5, as shown in fig. 4 (e).

The embodiment also provides a use method of the ion etching machine, which is based on the ion etching machine and comprises the following steps:

(1) an ion source baffle plate 1 is clamped at one side of the discharge chamber 2 close to the ion source Grid component 4;

(2) plasma is generated in the discharge chamber 2;

(3) after the plasma is shielded by the ion source baffle plate 1, the number of the plasma is gradually increased from the edge area of the discharge chamber 2 to the central area of the discharge chamber 2;

(4) the plasma is injected into the screen 41 of the ion source Grid assembly 4, and then sequentially passes through the screen 41 to form a plasma beam, which passes through the acceleration Grid 42 of the Grid assembly and is injected into the reaction chamber 32.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.