JP2011129556A - Electrode plate for plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode plate for a plasma processing apparatus that improves in-plane uniformity of plasma processing and facilitates replacement of an upper electrode having been consumed. <P>SOLUTION: The electrode plate 3 for the plasma processing apparatus is constituted by stacking a plurality of electrode constitution plates and providing a plurality of gas passing holes penetrating the electrode constitution plates along a thickness, a gap portion s1 being provided at an outer circumferential portion of a stacking surface between a fixed-side electrode constitution plate 3a and a discharge-side electrode constitution plate 3b, which are adjacent to each other, by cutting a part of the plate thickness along a circumferential direction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electrode plate for a plasma processing apparatus that discharges a plasma generating gas while passing it in the thickness direction in the plasma processing apparatus.

  A plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus used in a semiconductor device manufacturing process has, for example, an upper electrode and a lower electrode connected to a high-frequency power source disposed in a chamber facing each other in the vertical direction, With the substrate to be processed disposed on the electrode, plasma is generated by applying a high frequency voltage while etching gas is circulated from the through hole formed in the upper electrode toward the substrate to be processed, and etching is performed on the substrate to be processed. And the like.

As the upper electrode used in this plasma processing apparatus, a laminated electrode plate is generally used in which a silicon electrode plate is fixed to a cooling plate and overlapped, and the heat of the electrode plate rising during the plasma processing is cooled. It is configured to dissipate heat through the plate.
If the temperature distribution of the electrode plate becomes non-uniform during plasma processing, the etching depth varies depending on the location of the substrate to be processed, and uniform etching cannot be performed on the entire substrate to be processed. There is a need to.
Therefore, for example, in Patent Document 1, a cooling plate is fastened and fixed to the back surface of the electrode plate via a metal film in order to eliminate the non-uniformity of the temperature distribution of the electrode plate. Is required.

On the other hand, when the upper electrode is repeatedly subjected to the plasma treatment, the portion exposed to the plasma is scraped and consumed, so that the upper electrode needs to be replaced in accordance with the operation time of the apparatus.
For example, in Patent Document 2, as a cost reduction for replacement due to consumption of the upper electrode, the electrode plate has a two-body structure, and a part of the electrode plate can be replaced.
However, since this two-body structure electrode plate is deaerated and adhered in a vacuum state during plasma processing, it is not easily peeled off simply by removing the bolt, and it is difficult to replace only the worn electrode plate. there were.

Japanese Patent Laid-Open No. 11-256370 JP 2003-332314 A

  The present invention has been made in view of such circumstances, and provides an electrode plate for a plasma processing apparatus that can improve in-plane uniformity of plasma processing and can easily replace a worn upper electrode.

The electrode plate of the present invention is an electrode plate for a plasma processing apparatus in which a plurality of electrode component plates are laminated and a plurality of gas passage holes penetrating in the thickness direction of the electrode component plates are provided, and are adjacent to each other. The outer peripheral part between the opposing surfaces of the electrode constituent plates is provided with a gap formed by cutting out part of the thickness of at least one of the two electrode constituent plates along the circumferential direction.

  In this electrode plate, since the gap is provided on the outer periphery between the opposing surfaces of the laminated electrode component plates, the gap portion is interposed between both electrode component plates as a heat insulating space. The outer peripheral portion of the electrode plate has a greater heat insulation effect for heat transfer in the thickness direction than the central portion, thereby suppressing heat transfer in the thickness direction of the outer peripheral portion of the electrode plate that easily dissipates heat to the periphery, As a whole plate, the temperature difference between the outer peripheral portion and the central portion can be reduced.

The gap portion may be provided by cutting out only one of the adjacent electrode constituent plates, or may be provided by cutting out both.
In addition, by providing a gap, when replacing an electrode component plate that has been consumed due to plasma treatment, the stacked electrode component plate can be easily pulled by inserting a tool into the gap formed by the adjacent electrode component plate. It can be peeled off.

Moreover, the electrode plate of this invention WHEREIN: The said space | gap part is good to be provided in the perimeter of the said electrode structure board.
It is not always necessary to provide a gap around the entire circumference. However, when a gap is provided around the circumference, uniform heat dissipation is obtained, and in-plane uniformity is further improved.

And the said space | gap part is good to be formed by the chamfering surface which consists of the inclined surface or circular arc surface which notches the corner | angular part of the said electrode structure board.
When a tool inserted into the gap is used as an insulator, even if the tool is used with the chamfered surface side as a fulcrum, damage such as wear or chipping due to contact with the tool can be prevented. Therefore, it is possible to use the electrode plate soundly over a long period of time by using the electrode component plate provided with the chamfered surface as the fixed side.

According to the present invention, by providing a gap in the outer periphery of the laminated electrode component plates, the adjacent electrode component plates can be easily peeled off and replaced, and the heat in the thickness direction of the outer periphery easily radiates heat. The transmission is interrupted, and the heat transferability is controlled between the central portion and the outer peripheral portion of the electrode plate, so that in-plane uniform plasma processing can be performed.

(A) which shows 1st Embodiment of the electrode plate of this invention is a rear view of the electrode component board which has a chamfering surface in an outer peripheral part, (b) is a longitudinal cross-section of the electrode plate formed by laminating | stacking two electrode component plates FIG. It is a schematic block diagram which shows the example of the plasma processing apparatus in which the electrode plate of FIG. 1 is used. It is an enlarged view of the principal part X enclosed with the dashed-two dotted line shown in FIG.1 (b), (a) is a figure explaining the thermal radiation of an electrode plate, (b) is the state which inserted the tool in the space | gap part. It is a figure explaining. (A) which shows 2nd Embodiment of the electrode plate of this invention is a rear view of a stationary-side electrode component board, (b) is a longitudinal cross-sectional view of the electrode plate formed by laminating | stacking two electrode component plates. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the electrode plate of this invention.

Hereinafter, embodiments of the electrode plate of the present invention will be described with reference to the drawings.
First, a plasma etching apparatus 1 will be described as a plasma processing apparatus using this electrode plate.
As shown in the schematic cross-sectional view of FIG. 2, the plasma etching apparatus 1 is provided with an electrode plate (upper electrode) 3 in the upper part of the vacuum chamber 2 and a pedestal (lower electrode) 4 that can be moved up and down in the lower part. Are provided in parallel with the electrode plate 3 at a distance from each other. In this case, the upper electrode plate 3 is supported in an insulated state by the insulator 5 with respect to the wall of the vacuum chamber 2, and the electrostatic chuck 6 and the silicon-made surrounding material are placed on the mount 4. A support ring 7 is provided, and a wafer (substrate to be processed) 8 is placed on the electrostatic chuck 6 with the peripheral edge supported by the support ring 7. Further, an etching gas supply pipe 9 is provided in the upper part of the vacuum chamber 2, and the etching gas sent from the etching gas supply pipe 9 passes through the diffusion member 10 and then is a gas passage hole provided in the electrode plate 3. 11 is made to flow toward the wafer 8 and discharged from the discharge port 12 on the side of the vacuum chamber 2 to the outside. On the other hand, a high frequency voltage is applied between the electrode plate 3 and the gantry 4 by a high frequency power source 13.

  The electrode plate 3 is formed in a disk shape with silicon, and a cooling plate 14 made of aluminum or the like having excellent thermal conductivity is fixed to the back surface of the electrode plate 3, and the gas passing through the electrode plate 3 is also passed through the cooling plate 14. Through holes 15 are formed at the same pitch as the gas passage holes 11 so as to communicate with the holes 11. The electrode plate 3 is fixed in the plasma processing apparatus 1 by screwing or the like with the back surface in contact with the cooling plate. The detailed structure of the electrode plate 3 will be described later.

In the plasma etching apparatus 1, when an etching gas is supplied by applying a high-frequency voltage from a high-frequency power source 13, the etching gas passes through the diffusion member 10, passes through the gas passage hole 11 provided in the electrode plate 3, and is electrode plate. 3 is released into the space between the gantry 3 and the gantry 4 and becomes plasma in this space, hits the wafer 8, and the surface of the wafer 8 is etched by sputtering, ie, physical reaction, and chemical reaction of the etching gas. The
Further, for the purpose of uniformly etching the wafer 8, the generated plasma is concentrated on the central portion of the wafer 8, and is prevented from diffusing to the outer peripheral portion, thereby generating a uniform plasma between the electrode plate 3 and the wafer 8. In order to generate the plasma, the plasma generation region 16 is usually surrounded by a silicon shield ring 17.

Next, the detailed structure of the electrode plate 3 will be described with reference to FIG.
The electrode plate 3 is configured by laminating a fixed-side electrode constituting plate 3a and a discharge-side electrode constituting plate 3b, and both the electrode constituting plates 3a and 3b are discs made of single crystal silicon, columnar crystal silicon, or polycrystalline silicon. It is formed in a shape. A large number of gas passage holes 11 are provided on both electrode constituent plates 3a and 3b side by side on a plurality of concentric circles having different diameters.
Further, a chamfered surface 32a is formed on the outer periphery of the laminated surface 31a of the fixed-side electrode constituting plate 3a outside the formation region of the gas passage hole 11 and a part of the plate thickness is notched by an inclined surface over the entire circumference. Yes. The chamfered surface 32a of the fixed-side electrode component plate 3a and the discharge-side electrode component plate 3b are laminated by stacking the electrode component plates 3a and 3b with the discharge-side electrode component plate 3b facing the chamfered surface 32a. A gap s1 is formed between the electrode plate 3 and the laminated surface 31b over the entire circumference of the electrode plate 3 that opens outward in the radial direction of the electrode plate 3.

In the electrode plate 3 configured as described above, the heat of the electrode plate 3 rising during the plasma etching process is radiated through the cooling plate 14. A solid line arrow shown in FIG. 3A represents a heat flow by the cooling plate 14, and a broken line arrow represents heat radiation on the outer peripheral surface of the electrode plate 3.
At the center of the electrode plate 3, the heat that has risen at the discharge side electrode component plate 3b is quickly transferred to the cooling plate 14 via the fixed electrode component plate 3a that is in close contact with the discharge side electrode component plate 3b. The On the other hand, as shown in FIG. 3A, a part of the heat is radiated from the outer peripheral surface at the outer peripheral portion of the electrode plate 3, but the gap s1 is interposed between the electrode constituent plates 3a and 3b. The heat transfer from the discharge side electrode constituting plate 3b to the fixed side electrode constituting plate 3a is interrupted by the gap s1, and the heat transfer is suppressed accordingly.
Thus, since the electrode plate 3 is in a state in which heat transfer in the thickness direction is less likely to proceed in the outer peripheral portion than in the central portion, the outer peripheral portion is originally in a state where heat is easily radiated to the periphery in the radial direction or the like. Thus, as a sum of these, the entire electrode plate 3 is radiated heat evenly in the plane. This prevents a temperature difference from occurring between the central portion and the outer peripheral portion of the electrode plate 3, makes the temperature uniform in the surface, and in-plane uniformity of plasma processing, for example, in-plane uniformity of etching depth Can be improved.

In addition, the discharge side electrode constituting plate 3b of the electrode plate 3 is worn out by removing the portion exposed to the plasma by repeatedly performing the plasma treatment, and therefore needs to be replaced according to the operating time of the apparatus. As shown in FIG. 3B, the chamfered surface 32a provided on the fixed-side electrode constituting plate 3a acts as a guide for the tool T. Therefore, by inserting the tool T into the gap portion s1 along the chamfered surface 32a. The fixed-side electrode component plate 3a and the discharge-side electrode component plate 3b can be easily peeled off, and only the discharge-side electrode component plate 3b can be replaced.
In this case, the tool T inserted as shown by the arrow y in FIG. 3B is pushed inward in the radial direction as it is, or the fixed side electrode structure is formed by the lever principle while rotating the tool T as shown by the arrow z. Either the discharge-side electrode constituting plate 3b is peeled off from the plate 3a, or the two electrode constituting plates 3a and 3b can be separated by any method.

The gap portion s1 of the electrode plate 3 is composed of a chamfered surface 32a provided on the fixed side electrode constituting plate 3a and a planar shape of the laminated surface 31b of the opposing discharge side electrode constituting plate 3b. The corners of the fixed-side electrode constituting plate 3a forming s1 have a shape formed with an obtuse angle α of 90 degrees or more as shown in FIG. Therefore, when peeling off the fixed-side electrode component plate 3a and the discharge-side electrode component plate 3b, the tool T inserted into the gap s1 is used as a fulcrum as the fulcrum as shown by the arrow z in FIG. Even when used, damage such as wear or chipping due to contact with the tool T can be prevented. Thus, by providing the chamfered surface 32a on the fixed side electrode constituting plate 3a, the electrode plate 3 can be used soundly over a long period of time.

In the first embodiment, the gap portion s1 is provided on the entire circumference of the electrode plate 3. However, the gap may not necessarily be the entire circumference. In the second embodiment of FIG. 4, the electrode plate 20 is fixed to be attached to the cooling plate 14. Three cutout portions 23a forming the gap portion s2 are provided at equal intervals on the outer peripheral portion of the side electrode constituting plate 20a. In this case, the cutout portions 23a are arranged on the fixed side as shown in FIG. It is formed by making the corner | angular part of the electrode structure board 20a into the chamfering surface 22a of an inclined surface.
Even in the configuration in which the gap portion s2 is provided in a large part of the outer periphery as in the electrode plate 20 of the second embodiment, heat transfer in the outer peripheral portion of the electrode plate 20 can be suppressed. What is necessary is just the structure by which the space | gap part s2 is provided in most outer peripheral parts of the electrode structure board 20a, 20b.

FIG. 5 shows a third embodiment of the electrode plate of the present invention.
The electrode plate 40 of this embodiment uses the same electrode configuration plate 40a for the fixed side electrode configuration plate and the discharge side electrode configuration plate, and the surface on the side where the chamfered surface 42a of the electrode configuration plate 40a is provided. The gap portion s3 is provided so as to straddle the laminated surface of the two electrode component plates 40a.
As in the electrode plate 40 of the third embodiment, when the gap portion s3 is configured by the electrode configuration plate 40a having the same shape, the electrode plate can be configured by one type of electrode configuration plate, which is efficient.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the gap portion s1 provided in the electrode plate 3 of Embodiment 1 is configured by the inclined chamfered surface 32a provided in the fixed-side electrode component plate 3a. For example, the gap portion s1 is defined by using the chamfered surface 32a as an arc surface. It may be configured.

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 Vacuum chamber 3,20,40 Electrode plate 3a, 20a Fixed side electrode constituent plate 3b, 20b Discharge side electrode constituent plate 4 Base 5 Insulator 6 Electrostatic chuck 7 Support ring 8 Wafer 9 Etching gas supply pipe 10 Diffusion member 11 Gas passage hole 12 Discharge port 13 High frequency power supply 14 Cooling plate 15 Through hole 16 Plasma generation region 17 Shield rings 22a, 32a, 42a Chamfered surface 23a Notched portions 31a, 31b Laminated surface 40a Electrode component plate

Claims (3)

A plasma processing apparatus electrode plate in which a plurality of electrode component plates are stacked and a plurality of gas passage holes penetrating in the thickness direction of the electrode component plates are provided, between opposing surfaces of adjacent electrode component plates An electrode plate for a plasma processing apparatus is provided with a gap formed by notching a part of the thickness of at least one of the two electrode constituent plates along the circumferential direction.   The electrode plate for a plasma processing apparatus according to claim 1, wherein the gap is provided on the entire circumference of the electrode component plate. 3. The electrode plate for a plasma processing apparatus according to claim 1, wherein the gap is formed by a chamfered surface formed of an inclined surface or an arc surface that cuts out a corner of the electrode component plate. 4.

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