JP2005285845A - Gas-jetting board for plasma etching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-jetting board of a plasma etching apparatus whose surface hardly corrodes and which is superior in durability, even if it is continuously and directly exposed to plasma over a long time. <P>SOLUTION: The gas jetting board of the plasma etching device constitutes a part of an electrode board and can circulate the reactant gas in the inside. In the board, a plurality of through holes are formed and a compact silicon carbide layer is formed on a surface of a side where reactant gas is jetted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a gas blowing plate constituting a part of an electrode plate of a plasma etching apparatus which is a kind of semiconductor manufacturing apparatus.

Conventionally, for example, a plasma etching apparatus is known as a kind of semiconductor manufacturing apparatus using plasma. This apparatus exposes the silicon surface by selectively removing only the photosensitive region of the photosensitive film by exposing the silicon wafer after the exposure / development process to gas plasma.

In the chamber constituting the plasma etching apparatus, a pair of positive and negative electrode plates are arranged in a state of being separated in the vertical direction. A number of through holes are formed in the upper electrode plate along the thickness direction, and the reaction gas is supplied to the lower side through the through holes. A silicon wafer is disposed and fixed on the upper surface of the lower electrode plate in a state where the silicon wafer is fitted in the dummy ring.

In order to etch a silicon wafer using such a plasma etching apparatus, first, a silicon wafer that has undergone an exposure / development process is placed between the upper and lower electrode plates, and then the reaction gas is brought into a vacuum state or a low pressure state in the chamber. Fill.
Next, after generating a plasma by applying a high voltage between the upper and lower electrodes, a reactive gas is slowly blown into the chamber from the through-hole formed in the upper electrode plate, and reacts with the generated plasma. The silicon wafer was etched by blowing gas onto the silicon wafer.

Conventionally, in such a plasma etching apparatus, carbon or aluminum has been used as a material for the gas blowing plate.
However, since the gas blowing plate is in direct contact with the plasma, its surface is easily eroded, and the particles constituting the upper electrode plate fall off and adhere to the silicon wafer, causing particles to be generated. was there.

In addition, with the recent high integration and miniaturization of semiconductor devices, the performance required for the upper electrode plate has become more severe, and in order to reduce the generation of particles in the silicon wafer, Silicon that is not easily eroded by plasma has been used.
However, even if such a gas blowing plate made of silicon continues to be directly exposed to plasma, it is gradually eroded and silicon particles fall off and adhere to the silicon wafer, causing the generation of particles. It was.
In particular, the reaction of the gas blowing plate near and inside the reactive gas blowing port tends to be brittle because the reaction with the plasma is intense and the surface is eroded.

The present invention has been made in view of the above problems, and even when it is directly exposed to plasma for a long time, the surface thereof is hardly eroded, and the plasma etching apparatus is excellent in durability. An object is to provide a gas blowing plate.

The gas blowing plate of the plasma etching apparatus of the present invention is a gas blowing plate of the plasma etching apparatus that constitutes a part of the electrode plate and can circulate the reaction gas therein,
Many through holes are formed,
A dense silicon carbide layer is formed at least on the surface on the side from which the reaction gas is blown out.
Hereinafter, the present invention will be described in detail.

The gas blowing plate of the present invention is excellent in durability because the surface thereof is hardly eroded by the plasma, so that the particles do not fall off.

The present invention is a gas blowing plate of a plasma etching apparatus that constitutes a part of an electrode plate and allows a reaction gas to flow inside the electrode plate,
Many through holes are formed,
A gas blowing plate of a plasma etching apparatus, wherein a dense silicon carbide layer is formed at least on the surface on the side from which the reaction gas is blown.

FIG. 1A is a perspective view schematically showing an example of a gas blowing plate (hereinafter, also simply referred to as a gas blowing plate of the present invention) of the plasma etching apparatus of the present invention, and FIG. FIG. Moreover, Fig.2 (a) is the perspective view which showed typically another example of the gas blowing plate of this invention, (b) is the longitudinal cross-sectional view. 3A is a perspective view schematically showing still another example of the gas blowing plate of the present invention, and FIG. 3B is a longitudinal sectional view thereof.

As shown in FIGS. 1 (a) and 1 (b), the gas blowing plate 10 of the present invention has a disk shape in which a large number of through-holes 13 are formed, and one surface of the disk-shaped base portion 12 is formed. A dense silicon carbide layer 11 is formed so as to cover the side surfaces.
In such a gas blowing plate 10, the reactive gas is blown out from the through hole 13 on the surface on which the dense silicon carbide layer 11 is formed.

Further, as shown in FIGS. 2A and 2B, another gas blowing plate 20 of the present invention has a disk shape in which a large number of through holes are formed, and Dense silicon carbide layer 21 is formed so as to cover the entire surface.
In such a gas blowing plate 20, the reactive gas may be blown out from either side of the gas blowing plate 20.

Further, as shown in FIGS. 3A and 3B, in another gas blowing plate 30 of the present invention, a large number of through holes 33 are formed in a disk-shaped dense silicon carbide layer 31.
In such a gas blowing plate 30, the reaction gas may be blown from either side of the gas blowing plate 30.

As described above, the gas blowing plate of the present invention is only required to have a large number of through holes and at least a dense silicon carbide layer formed on the surface on which the reaction gas is blown.
Therefore, the gas blowing plate of the present invention may have any structure of the gas blowing plates 10, 20 and 30 shown in FIGS.
Therefore, in the following description, the structure of the gas blowing plate of the present invention is assumed to be the gas blowing plate 10 shown in FIG.

The shape of the gas blowing plate 10 of the present invention is not limited to the disc shape as shown in FIG. 1, and may be any shape such as an elliptical shape or a polygonal shape in plan view as long as it is a plate shape. In general, since a silicon wafer as an object to be processed has a substantially disc shape, a disc-like one such as the gas blowing plate 10 shown in FIG. 1 is often used.

In the gas blowing plate 10 of the present invention, the dense silicon carbide layer 11 refers to a dense layer made of silicon carbide. As such a dense silicon carbide layer 11, for example, a chemical vapor deposition method ( Hereinafter, a CVD layer formed by a CVD method), a sintered body layer made of a dense silicon carbide sintered body, and the like can be given. Among these, a CVD layer is desirable. This is because a dense silicon carbide layer can be reliably formed on the base material portion 12.
However, when the gas blowing plate of the present invention is composed of a base material portion and a dense silicon carbide layer as shown in FIGS. 1 and 2 and both are made of silicon carbide, the base material portion is a sintered body. It is desirable that the dense silicon carbide layer be a CVD layer.

Since the dense silicon carbide layer 11 is formed on one surface and side surface of the base material portion 12, the diameter of the portion formed on the surface of the base material portion 12 is appropriately set according to the diameter of the base material portion 12. It is determined.
Moreover, it does not specifically limit as thickness of the dense silicon carbide layer 11, It is desirable that it is about 0.2-5 mm. When the thickness of the dense silicon carbide layer 11 is less than 0.2 mm, it is quickly worn out by the plasma, and the base material portion 12 is exposed to the plasma and the particles constituting the base material portion 12 are dropped off. May end up. On the other hand, if the thickness of the dense silicon carbide layer 11 exceeds 5 mm, the thickness is sufficient, and if the dense silicon carbide layer 11 is made thicker than this, it is disadvantageous in terms of time and cost.

However, when the gas blowing plate of the present invention has a structure made of only dense silicon carbide, such as the gas blowing plate 30 shown in FIG. 3, the diameter is the same as the dense silicon carbide layer 11 described above. It is desirable that the thickness be about 1 to 5 mm. If it is less than 1 mm, the strength is low, and warping may occur due to its own weight or damage may occur. On the other hand, if it exceeds 5 mm, the thickness is sufficient, and if it is thicker than this, it is disadvantageous in terms of economy and cost.

In addition, the average particle diameter of the silicon carbide particles constituting the dense silicon carbide layer 11 is not particularly limited, but is preferably about 1 to 20 μm, for example. When the average particle diameter of the silicon carbide particles exceeds 20 μm, the particle diameter becomes too large to form a dense structure, and the silicon carbide particles may be easily dropped by being exposed to plasma. On the other hand, it is practically difficult to make the average particle diameter of the silicon carbide particles 1 μm or less.

The maximum particle size of the silicon carbide particles is desirably 40 μm or less. That is, it is desirable that the silicon carbide particles constituting the dense silicon carbide layer 11 have a relatively uniform particle size. When the maximum particle size of the silicon carbide particles exceeds 40 μm, even if the average particle size of the silicon carbide particles is within the above-described range, the silicon carbide particles exceeding 40 μm are not included in the dense silicon carbide layer 11. It is much larger than the other silicon carbide particles that constitute, and easily drops off from the dense silicon carbide layer 11.

The silicon carbide particles constituting the dense silicon carbide layer 11 are β-type silicon carbide having a zinc-blende crystal structure. The crystal orientation of such a dense silicon carbide layer 11 depends on the formation during manufacture. It can be changed by adjusting the film conditions.
Moreover, when the crystal plane of the dense silicon carbide layer 11 has a single orientation plane, the silicon carbide crystal is desirably oriented in the (111) plane. Since the intercrystal distance of the silicon carbide crystal oriented in the (111) plane is shorter than the intercrystal distance of the silicon carbide crystal oriented in the (220) plane, it has excellent strength and is less likely to be eroded by plasma. is there. The crystal plane can be confirmed by analyzing the X-ray diffraction pattern of the dense silicon carbide layer 11.

In addition, it is desirable that crystals having different orientations are mixed in the dense silicon carbide layer 11. Specifically, it is desirable that a crystal plane oriented in the (111) plane and a crystal plane oriented in the (220) plane are mixed. This is because the orientation transition of the silicon carbide crystal constituting the dense silicon carbide layer 11 is liable to occur and is less likely to be eroded by plasma. In this case, the dense silicon carbide layer 11 may have a structure in which a crystal plane oriented in the (111) plane and a crystal plane oriented in the (220) plane are uniformly or locally mixed. It may be a multilayer structure in which a silicon carbide layer oriented in the plane) and a silicon carbide layer oriented in the (220) plane are laminated.

Further, when the dense silicon carbide layer 11 includes a silicon carbide crystal oriented in the (111) plane and a silicon carbide crystal oriented in the (220) plane, the silicon carbide crystal oriented in the (111) plane However, it is desirable that there are more than silicon carbide crystals oriented in the (220) plane. As described above, the intercrystalline distance of the silicon carbide crystal oriented in the (111) plane is shorter than the intercrystalline distance of the silicon carbide crystal oriented in the (220) plane. Hard to be eroded. Therefore, in the dense silicon carbide layer 11 in which the silicon carbide crystal oriented in the (111) plane and the silicon carbide crystal oriented in the (220) plane are mixed, the silicon carbide crystal oriented in the (111) plane is expressed as (220 ) By increasing the number of silicon carbide crystals in the plane, the strength of the dense silicon carbide layer 11 can be improved, and it can be made difficult to be eroded by plasma. Specifically, in the dense silicon carbide layer 11, it is desirable that the crystal plane oriented in the (220) plane is more than 15% and less than 50%.

In addition, the dense silicon carbide layer 11 is formed in the dense silicon carbide layer 11 when the silicon carbide crystal oriented in the (111) plane and the silicon carbide crystal oriented in the (220) plane are mixed. It is desirable that more crystals oriented in the (220) plane are mixed in the peripheral portion of the through hole 13 than in portions other than the peripheral portion of the through hole 13.
The peripheral part of the through-hole 13 is more easily eroded by plasma than the part other than the peripheral part of the through-hole 13 and needs to be superior in strength. Further, in the dense silicon carbide layer 11, the more the silicon carbide crystals oriented in the (220) plane are mixed, the greater the degree of mixing between the two, and the orientation transition of the silicon carbide crystals is likely to occur. Since stress acting on the fine silicon carbide layer 11 can be easily relaxed, corrosion of the dense silicon carbide layer 11 due to the plasma due to the plasma can be prevented.
Therefore, the peripheral portion of the through-hole 13 is eroded by plasma by making the silicon carbide crystal oriented in the (220) plane more than the other portion in the peripheral portion of the through-hole 13. It becomes difficult.
However, even in this case, it is desirable that more silicon carbide crystals oriented in the (111) plane exist than silicon carbide crystals oriented in the (220) plane.

Moreover, it is desirable that the content of impurities other than Si, C, O, N, and Y in the dense silicon carbide layer 11 is 5 ppm or less. When the impurity content exceeds 5 ppm, as the dense silicon carbide layer 11 is gradually worn by the plasma, the impurity diffuses into the plasma and adheres to the silicon wafer, resulting in a decrease in purity. It may end up.

Furthermore, the thickness of the work brittle layer on the reactive gas blowing side of the dense silicon carbide layer 11 is desirably 30 μm or less. When the thickness of the work brittle layer exceeds 30 μm, the work brittle layer is directly exposed to the plasma, so that the silicon carbide particles in the work brittle layer easily fall into the plasma and adhere to the silicon wafer. There is.
A specific method for setting the thickness of the work brittle layer on the reactive gas blowing side of the dense silicon carbide layer 11 to 30 μm or less will be described in detail in the method for producing a gas blowing plate of the plasma etching apparatus of the present invention described later. To do.

The base material portion 12 may be a dense body or a porous body. The material constituting the base material portion 12 is not particularly limited, and examples thereof include arbitrary materials such as silicon carbide, silicon, and carbon.
Of these, silicon carbide is desirable. This is because it is made of the same material as that of the dense silicon carbide layer 11, so that the adhesive strength between the dense silicon carbide layer 11 and the base material portion 12 is excellent.
Moreover, as for the base material part 12, it is more desirable that it is porous silicon carbide. Since the impregnated layer impregnated with silicon carbide can be formed in the vicinity of the surface in contact with the dense silicon carbide layer 11 of the base material portion 12, an anchor effect can be obtained, and the dense silicon carbide layer 11 is obtained. And the adhesive strength between the substrate portion 12 and the substrate portion 12 are very excellent. Further, since the reaction gas can be circulated in the inside, the reaction gas can be introduced into the plasma etching apparatus in a uniform state.

When base material portion 12 is made of a porous body and an impregnation layer impregnated with silicon carbide is formed in the vicinity of the surface of base material portion 12 that is in contact with dense silicon carbide layer 11, The thickness is desirably 10 to 30 μm. When it is less than 10 μm, the adhesive strength between the base material portion 12 and the dense silicon carbide layer 11 is hardly improved. On the other hand, if it exceeds 30 μm, the adhesive strength between the base material portion 12 and the dense silicon carbide layer 11 is sufficient, and conversely, it takes a long time to form such a thick impregnated layer. Disadvantageous.

Moreover, when the base material part 12 consists of porous bodies, it is desirable that the porosity is 30 to 50%. When the porosity is less than 30%, it becomes difficult to circulate the reaction gas in the inside thereof, so that the effect of introducing the reaction gas into the plasma etching apparatus in a uniform state may not be sufficiently obtained. . On the other hand, if the porosity exceeds 50%, the mechanical strength of the base material portion 12 is weakened, so that cracks are likely to occur, and the particles constituting the base material portion 12 are likely to drop out, and the dropped particles May adhere to an object to be processed such as a silicon wafer and cause generation of particles.

Moreover, when the base material part 12 consists of a porous body, it is desirable for the minimum of the average particle diameter of the particle | grains which comprise the base material part 12 to be 2 micrometers, and it is more desirable that it is 10 micrometers. On the other hand, the upper limit of the average particle size of the particles is desirably 150 μm, and more desirably 70 μm. If the average particle size of the particles is less than 2 μm, the pore diameter of the pores present inside the particles will be too small and the reaction gas will not flow easily, so the reaction gas is introduced into the plasma etching apparatus in a uniform state. It may not be possible to obtain a sufficient effect. On the other hand, if the average particle diameter of the particles exceeds 150 μm, the pore diameter of the pores present in the particles becomes too large, and the strength of the gas blowing plate 10 may be reduced. Moreover, it is not so easy to produce a sintered body having particles having a predetermined ratio of open pores and having an average particle size exceeding 150 μm.

Moreover, when the base material part 12 consists of a dense body, it is desirable that the average particle diameter of the particle | grains which comprise the base material part 12 is 1-100 micrometers. This is because the base material portion 12 can be made into a dense body having excellent strength.

The diameter of the gas blowing plate 10 is appropriately determined according to the diameter of the object to be processed such as a silicon wafer, but the lower limit is preferably about 200 mm, and the upper limit is preferably about 500 mm. If it is less than 200 mm, only plasma etching of a silicon wafer having a small diameter can be performed, and it is not possible to cope with the recent increase in the diameter of silicon wafers. On the other hand, if it exceeds 500 mm, it can sufficiently cope with the recent increase in the diameter of silicon wafers, but since the plasma etching apparatus becomes large, it is necessary to generate a large amount of plasma, which is disadvantageous in terms of time and cost. Become. In addition, it becomes difficult to uniformly etch the silicon wafer. The lower limit of the diameter of the gas blowing plate 10 is 300 mm, and the upper limit is more preferably 500 mm. This is to cope with silicon wafers of 12 inches or more, which will be the next-generation mainstream.

Moreover, it does not specifically limit as thickness of the gas blowing board 10, Usually, it is desirable that it is 2-30 mm. When the thickness is less than 2 mm, warpage is likely to occur, and the mechanical strength is reduced, and cracks are likely to occur. On the other hand, if the thickness exceeds 30 mm, it has sufficient strength, but the weight of the gas blowing plate 10 increases, resulting in poor handling.

The through holes 13 are formed so as to be uniformly distributed on the main surface of the gas blowing plate 10 of the present invention. This is because the reaction gas is allowed to flow inside the gas blowing plate 10 and blown out uniformly into the plasma etching apparatus. Further, the number of the through holes 13 is not particularly limited, and is appropriately determined according to the size of the target gas blowing plate, the size of the through holes, and the like.

Although the diameter of the through-hole 13 is not specifically limited, Usually, it is desirable that it is 0.1-1 mm. If the diameter of the through hole 13 is less than 0.1 mm, clogging is likely to occur, and the reactive gas may not be able to be blown into the plasma etching apparatus with a uniform blowing direction and blowing amount. On the other hand, when the diameter of the through hole 13 exceeds 1 mm, plasma may flow into the through hole and the gas blowing plate of the present invention may be eroded.

In the gas blowing plate 10 of the present invention, it is desirable that the reactive gas blowing port of the through hole 13 is chamfered. This is because if the reaction gas outlet of the through-hole 13 is angular, the plasma tends to intensively strike this portion, the reaction gas outlet is corroded, and silicon carbide particles are likely to fall off.

The chamfering may be C chamfering or R chamfering.
When the chamfering is C chamfering, the chamfering width and height are preferably 0.1 to 0.5 mm. When the chamfering is R chamfering, the radius of the curved surface is 0.1 to 0.5 mm. It is desirable to be.

When the chamfering width and height of the C chamfer and the radius of the curved surface of the R chamfer are less than 0.1 mm, the reactive gas outlet of the through hole 13 is in an angular state, and plasma is concentrated on the reactive gas outlet. The silicon carbide particles may fall off easily. On the other hand, when the chamfered chamfer width and height and the radius of the curved surface of the R chamfer exceed 0.5 mm, the diameter of the through hole on the side facing the plasma increases, and the plasma easily enters the through hole 13. , Plasma backflow is likely to occur, and plasma is not generated uniformly.

Further, the surface roughness Ra according to JIS B 0601 on the gas blowing side of the gas blowing plate 10 of the present invention is preferably as small as possible. Specifically, the gas blowing side of the gas blowing plate 10 of the present invention is irradiated with plasma for 5 hours. The surface roughness Ra of the peripheral portion of the through-hole 13 of the dense silicon carbide layer 11 is desirably 0.05 μm or less, and the surface of the portion other than the peripheral portion of the through-hole 13 of the dense silicon carbide layer 11 The roughness Ra is preferably 0.1 to 0.2 μm.
Since the peripheral portion of the through-hole 13 of the dense silicon carbide layer 11 is a portion that is very susceptible to erosion by plasma, when the surface roughness Ra exceeds 0.05 μm, the silicon carbide particles fall off due to erosion by the plasma. In some cases, the particles adhere to an object to be processed such as a silicon wafer and cause particles.
If the surface roughness Ra of the portion other than the peripheral portion of the through-hole 13 of the dense silicon carbide layer 11 is less than 0.1 μm, the surface roughness Ra is sufficiently flat, and the surface roughness Ra is further reduced. Is disadvantageous in terms of time and cost. On the other hand, when the surface roughness Ra of the surface of the dense silicon carbide layer 11 exceeds 0.2 μm, the silicon carbide particles easily fall off when directly exposed to plasma, and particles are generated on an object to be processed such as a silicon wafer. It may cause.

When performing plasma etching of a silicon wafer that has undergone exposure and development using the gas blowing plate of the present invention having such a configuration, the plasma etching apparatus provided with the gas blowing plate is used.

FIG. 4 is a cross-sectional view schematically showing an example of a plasma etching apparatus provided with the gas blowing plate of the present invention.
As shown in FIG. 4, the plasma etching apparatus 40 includes a chamber 44, a blowing plate support member 46 that is provided near the center of the upper surface of the chamber 44, supports the gas blowing plate 10 and the upper electrode plate 42, and the chamber The lower electrode plate 45 is provided in the vicinity of the center of the lower surface on the inner side of 44 and on which the silicon wafer 19 fitted in the dummy ring 48 is placed.

The upper electrode plate 42 and the lower electrode plate 45 are each electrically connected to an AC power source, and the upper electrode plate 42 functions as a positive electrode and the lower electrode plate 45 functions as a negative electrode. .
A gas plasma 400 can be generated between the upper electrode plate 42 and the lower electrode plate 45 by applying a voltage to the upper electrode plate 42 and the lower electrode plate 45.

The chamber 44 is a container for performing a plasma etching process on the silicon wafer 19 and is generally cylindrical in shape, and includes a gas blowing plate 10, an upper electrode plate 42, a lower electrode plate 45 and silicon. As long as the wafer 19 or the like can be accommodated, the chamber 44 may have an arbitrary shape such as a prismatic shape or an elliptical prism shape.
In addition, an exhaust port 43 for evacuating the chamber 44 or exhausting a reaction gas or the like to the outside is provided in a part of the lower surface of the chamber 44. The exhaust port 43 is provided on the bottom surface of the chamber 44, but may be formed on the side surface of the chamber 44, for example.
Further, the chamber 44 may be configured by a single member, but may be configured by joining a plurality of members as long as the internal airtightness can be ensured.

The gas blowing plate support member 46 has an opening formed on the lower surface thereof, and the upper electrode plate 42 and the gas blowing plate 10 can be fitted and fixed in the opening. Further, a supply pipe 460 is formed on the upper surface of the blowing plate support member 46 so that a reaction gas or the like can be supplied to the upper electrode plate 42 and the gas blowing plate 10.
Such a gas blowing plate support member 46 is fixed to the upper inner wall surface of the chamber 44, and the upper electrode plate 42 and the gas blowing plate 10 fixed to the opening on the lower surface thereof are disposed inside the chamber 44. On the other hand, the supply pipe 460 formed on the upper surface thereof is arranged outside the chamber 44.

The upper electrode plate 42 and the lower electrode plate 45 can be the same as those used in a conventionally known plasma etching apparatus, but the upper electrode plate 42 allows a reaction gas to flow therethrough. It has a structure that can.
As such an upper electrode plate 42, for example, a structure in which a large number of through holes communicating with the through holes of the gas blowing plate are provided in the thickness direction, or a number of concentric circular shapes on the surface of the gas blowing plate 10 side. Examples include a structure in which grooves are formed and a number of through-holes penetrating the bottom surface of these grooves and the opposite surface of the gas blowing plate 10 are provided.
The diameters of the upper electrode plate 42 and the lower electrode plate 45 are preferably at least the same as the diameter of the silicon wafer 19. This is because plasma is generated at least in a space directly above the silicon wafer 19.

A fitting recess for fitting the silicon wafer 19 is provided in the central portion of the upper surface of the dummy ring 48. By fitting the silicon wafer 19 into the fitting recess, the outer peripheral portion of the bottom surface of the silicon wafer 19 is provided. The entire circumference is supported to prevent the silicon wafer 19 from moving during the plasma etching process.
Although not shown, the dummy ring 48 is provided with a drive mechanism so that it can move with the silicon wafer 19 by a predetermined range in the vertical direction. That is, by changing the distance from the gas blowing plate 10 to the silicon wafer 19, the irradiation state of the gas plasma 400 can be appropriately adjusted.

In order to perform plasma etching on the silicon wafer 19 using such a plasma etching apparatus 40, first, each member is arranged as described above. Then, the inside of the chamber 44 is brought into a vacuum or low pressure state, and the reaction gas is filled into the chamber 44 from the supply pipe 460 through the upper electrode plate 42 and the gas blowing plate 10, and then the upper electrode plate 42 and the lower electrode plate 45 A voltage is applied to generate a gas plasma 400 between them.
Next, the reaction gas is slowly supplied from the supply pipe 460 into the blowing plate support member 46, and the reaction gas is blown into the chamber 44 through the upper electrode plate 42 and the gas blowing plate 10.
Then, the gas plasma 400 moves onto the silicon wafer 19 on the flow of the blown-out reaction gas, so that the silicon wafer 19 is subjected to plasma etching.

As described above, the gas blowing plate of the present invention has a large number of through holes formed therein, and at least a dense silicon carbide layer is formed on the surface on the side from which the reaction gas is blown out. In the plasma etching apparatus to which is attached, the reaction gas that has circulated through the through hole is blown into the plasma through the dense silicon carbide layer.
Therefore, the gas blowing plate of the present invention in which a dense silicon carbide layer that is hardly eroded even when directly exposed to plasma is formed on the surface exposed to plasma that is most exposed to plasma is easily eroded by plasma. No silicon carbide particles that fall off are present, and the durability is excellent.

Next, a method for manufacturing the gas blowing plate 10 shown in FIG. 1 will be described as a method for manufacturing the gas blowing plate of the plasma etching apparatus of the present invention.
In order to manufacture the gas blowing plate 10 of the present invention, first, the base material portion 12 is manufactured.
As described in the gas blowing plate of the present invention, the base material portion 12 may be a porous body or a dense body, and the material thereof is not particularly limited. It is desirable to be. Therefore, in the following description, the base material portion 12 is porous silicon carbide when it is a porous body, and is a dense silicon carbide sintered body when it is a dense body.

First, the case where the base material part 12 consists of porous silicon carbide is demonstrated.
When the base material part 12 consists of porous silicon carbide, first, the mixed composition containing a silicon carbide powder, a binder, and a dispersion medium liquid is prepared.

The particle size of the silicon carbide powder is preferably less shrinkage in the subsequent firing step, for example, 100 parts by weight of silicon carbide powder having an average particle size of about 0.3 to 50 μm, and 0.1 to 1. A combination of 5 to 65 parts by weight of silicon carbide powder having an average particle size of about 0 μm is desirable.

Examples of the binder include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, polyvinyl alcohol, phenol resin, epoxy resin, and acrylic resin. Usually, the amount of the binder is desirably about 1 to 10 parts by weight with respect to 100 parts by weight of the silicon carbide powder.

The dispersion medium liquid is not particularly limited, and examples thereof include organic solvents such as benzene and cyclohexane, alcohols such as methanol, and water. The dispersion medium liquid is blended in an appropriate amount so that the viscosity of the silicon carbide powder, binder, etc. is within a certain range.

Moreover, the dispersing agent may be contained with the said silicon carbide powder, the binder, and the dispersion medium liquid. The dispersant is not particularly limited, and examples thereof include phosphate ester compounds such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris (2-chloroethyl) phosphate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, and the like. Can be mentioned. Moreover, it is desirable that 0.1 to 5 parts by weight of this dispersant is added to 100 parts by weight of silicon carbide powder.

The mixed composition can be prepared by mixing the silicon carbide powder, binder, dispersion medium and the like with a vibration mill, attritor, ball mill, colloid mill, high-speed mixer, etc., and then kneading sufficiently with a kneader or the like. it can.

Next, this mixed composition is granulated by a spray drying method or the like, and then subjected to press molding by cold isostatic pressure (CIP) to form a predetermined shape to produce a green sheet. The green sheet may be produced by an extrusion method, a doctor blade method, or the like.

Next, the green sheet is degreased.
The degreasing is desirably performed by heating the green sheet to 400 to 650 ° C. in an oxygen-containing atmosphere. Most of the binder and the like contained in the green sheet can be volatilized.

And the baking process which bakes the green sheet which performed the said degreasing | defatting in inert atmosphere is performed, and the base material part 12 which consists of porous silicon carbide is manufactured.

In the firing step, the inert atmosphere is not particularly limited, and examples thereof include a gas atmosphere composed of at least one selected from nitrogen, argon, helium, neon, hydrogen, and carbon monoxide. Note that the firing furnace may be in a vacuum state.
Further, the lower limit of the firing temperature is desirably 1700 ° C., and more desirably 2000 ° C. The upper limit of the firing temperature is preferably 2400 ° C, and more preferably 2300 ° C.
When the firing temperature is less than 1700 ° C., it is difficult to sufficiently develop a neck portion for bonding silicon carbide particles to each other, and it may be impossible to achieve high thermal conductivity and high strength. On the other hand, when the firing temperature exceeds 2400 ° C., thermal decomposition of silicon carbide starts, and the strength of the sintered body decreases. Moreover, the amount of thermal energy required for firing increases, which is disadvantageous in terms of cost.

Further, during this firing treatment, it is desirable to suppress the volatilization of silicon carbide from the molded body in order to promote the growth of the neck portion. As a method for suppressing volatilization from the molded body, it is desirable to insert the molded body into a heat-resistant container capable of blocking the entry of outside air. As a material for forming the heat-resistant container, graphite or silicon carbide is suitable.

Next, the case where the base material part 12 consists of a dense silicon carbide sintered body is demonstrated.
In order to manufacture the base material portion 12 made of dense silicon carbide, first, a mixed composition containing at least silicon carbide powder, a binder, and a dispersion medium liquid is prepared.

The particle size of the silicon carbide powder is preferably 10 to 100 μm. This is because a dense silicon carbide substrate can be obtained by using silicon carbide particles having such a particle size. The silicon carbide powder may be either α-type silicon carbide powder or β-type silicon carbide powder.

The binder is not particularly limited. For example, a phenol resin, an epoxy resin, an oligoester acrylate, a xylene resin, a guanamine resin, a diallyl phthalate resin, a DFK resin, a furan resin, an amino resin, or other thermosetting resin, and other acrylic resins. , Polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol and the like. Among these, thermosetting resins are desirable, and phenol resins are particularly desirable. This is because the strength of the silicon carbide substrate to be manufactured is excellent.

Moreover, as said dispersion medium liquid, the thing similar to the dispersion medium liquid in case the base material layer 12 mentioned above consists of porous silicon carbide can be mentioned. The mixed composition may contain the same dispersant as the base material layer 12 made of the porous silicon carbide.

Next, this mixed composition is granulated by a spray drying method or the like, and then put into a mold having a desired shape, and a predetermined pressure is applied to form a molded body (generated shape).

The granules preferably have a moisture content of 0.1 to 2.0% by weight, and the granules are preferably heat-treated. This is because the strength of the base material portion 12 to be manufactured is excellent. As heating conditions at this time, it is desirable that the heating temperature is 50 to 100 ° C. and the heating time is 3 to 9 hours.

By subjecting the granule to rubber press molding, injection molding, extrusion molding, casting molding, or the like, a molded body (generated shape) having substantially the same shape as the base material portion 12 shown in FIG. 1 can be formed.
Moreover, when forming the said molded object, you may use a cold isostatic pressure (CIP) method, The lower limit of the molding pressure at this time is desirably 96MP, and it is more desirable that it is 106MPa. Further, the upper limit of the molding pressure is desirably 144 MPa, and more desirably 134 MPa. This is because the strength and density of the molded body to be molded are increased.

And the base material part 12 which consists of a dense silicon carbide sintered compact can be manufactured by performing a degreasing process and a baking process to the said molded object.
Examples of the degreasing treatment and firing treatment include the same conditions as the degreasing treatment and firing treatment in the base material portion 12 made of porous silicon carbide described above.

Next, a dense silicon carbide layer 11 having a thickness of about 0.2 to 5 mm is formed on the base member 12 made of the produced porous body or dense body.
As described in the gas blowing plate of the present invention, examples of the dense silicon carbide layer 11 include a CVD layer formed by a CVD method, a sintered body layer made of a dense silicon carbide sintered body, and the like. When base material portion 12 and dense silicon carbide layer 11 are both made of silicon carbide, base material portion 12 is preferably made of a sintered body, and dense silicon carbide layer 11 is preferably made of a CVD layer.
Therefore, in the following description, the base material part 12 shall be a CVD layer formed by CVD method.
The CVD method is preferably a thermal CVD method. This is because, in addition to being suitable for mass production, a dense silicon carbide layer can be reliably formed even if the base material portion 12 is not a simple shape.

In the CVD method, hydrogen or the like is used as a carrier gas, and a silicon-containing gas and a carbon-containing gas are reacted in the gas phase or the surface of the substrate portion 12, or a gas containing silicon and carbon at the same time in the gas phase or By reacting on the surface of the base material portion 12, the dense silicon carbide layer 11 is laminated on the base material portion 12.
The silicon-containing gas is not particularly limited, and examples thereof include SiCl ₄ gas and SiH ₂ Cl ₂ gas. The carbon-containing gas is not particularly limited, and examples thereof include CCl ₄ gas and C _2. H ₂ gas, CH ₃ gas, C ₃ H ₈ gas, C ₇ H ₈ gas, C ₆ H ₁₄ gas and the like can be mentioned.
Further, no particular limitation is imposed on the gas containing the aforementioned silicon and carbon at the same time, for _{example, CH 3 SiCl 3, CH 3} SiCl 3, (CH 3) 2 SiCl 3, (CH 3) 3 SiCl, (CH 3) ₄ Si, CH ₃ SiHCl _{2 and the} like.

Here, as described in the gas blowing plate of the present invention, when the dense silicon carbide layer 11 has a single orientation plane, the crystal plane of the silicon carbide crystal is oriented in the (111) plane. It is desirable. Thus, in order to orient the silicon carbide crystals of the dense silicon carbide layer 11 to the (111) plane, the temperature and flow rate of the source gas that becomes the dense silicon carbide layer 11 when performing the CVD method may be adjusted. Specifically, for example, the temperature may be adjusted to 1000 to 1300 ° C., and the flow rate may be adjusted to about 0.5 to 3 L / min.

Furthermore, as described in the gas blowing plate of the present invention, when the dense silicon carbide layer 11 includes crystals with different orientations, the dense silicon carbide layer 11 is oriented to the (111) plane and the (220) plane. It is desirable that the crystal plane is mixed.
However, in the dense silicon carbide layer 11, it is desirable that more silicon carbide crystals oriented in the (111) plane exist than silicon carbide crystals oriented in the (220) plane. It is as having demonstrated in the gas blowing plate of this invention.

As a structure in which the silicon carbide crystal constituting the dense silicon carbide layer 11 is oriented in the (111) plane and the (220) plane are mixed, for example, on the base material portion 12 A multilayer structure in which a dense silicon carbide layer oriented in the (111) plane is formed, and then a dense silicon carbide layer oriented in the (220) plane, or a silicon carbide crystal oriented in the (111) plane, 220) and a structure in which silicon carbide crystals oriented in the plane are mixed.

When the dense silicon carbide layer 11 has the multilayer structure, for example, a silicon carbide layer oriented in the (111) plane is formed on the base material portion 12 by the CVD method under the conditions described above, and then the silicon carbide layer is formed on the silicon carbide layer. Furthermore, a silicon carbide layer in which silicon carbide crystals are oriented in the (220) plane may be formed by the CVD method. In order to form the silicon carbide layer in which the silicon carbide crystal is oriented in the (220) plane, for example, when performing the CVD method, the temperature of the source gas described above is 1200 to 1500 ° C., and the flow rate is about 2 to 5 L / min. You may adjust to.
The multilayer structure is not limited to the above-described one. For example, after forming a silicon carbide layer oriented in the (220) plane on the base material portion 12, silicon carbide oriented in the (111) plane The structure in which the layer was formed may be sufficient, and the structure in which these silicon carbide layers were formed in multiple layers may be sufficient.

Further, when the dense silicon carbide layer 11 has a structure in which silicon carbide crystals oriented in the (111) plane and silicon carbide crystals oriented in the (220) plane are mixed, for example, a CVD method is performed on the substrate portion 12. When performing, the temperature of the source gas mentioned above may be adjusted to 1100 to 1300 ° C. and the flow rate to about 2 to 3 L / min.

Furthermore, when the base material part 12 consists of porous silicon carbide, it is desirable that an impregnation layer impregnated with silicon carbide is formed in the vicinity of the surface in contact with the dense silicon carbide layer 11. The thickness of the impregnated layer is desirably 10 to 30 μm. As described above.

In the dense silicon carbide layer 11 laminated on the base material portion 12 in this manner, the average particle size of the silicon carbide particles is preferably 1 to 20 μm, and the impurity content is 5 ppm or less. desirable. This is as described in the gas blowing plate of the present invention.

Next, the through-hole 13 is formed in the predetermined position of the plate-shaped body which formed the dense silicon carbide layer 11 on the base material part 12 which consists of a porous body or a dense body.
The through hole 13 can be formed by machining such as drilling, for example.

In addition, as described in the gas blowing plate of the present invention, crystals oriented in the (220) plane are formed in the peripheral portion of the through-hole 13 of the dense silicon carbide layer 11 rather than the portion other than the peripheral portion of the through-hole 13. It is desirable to exist more.
Such a gas blowing plate can be manufactured as follows.

FIGS. 5A to 5E are manufacturing process diagrams schematically showing a method of forming a dense silicon carbide layer on a base material portion.

First, a large number of openings 530 serving as through holes are formed at predetermined positions of the base material portion 52 (see FIG. 5A). The size of the opening 530 is adjusted to be the same size as the through hole 53. The base material portion 52 may be a porous body or a dense body.

Next, the carbon rod-like body 54 that can be just fitted into the opening 530 is fitted into the opening 530 so that one end of the carbon rod-like body 54 protrudes by about 0.5 to 5.5 mm (FIG. 5 ( b)).

Next, dense silicon carbide layer 51 is formed under the condition that the silicon carbide crystal is oriented in the (111) plane by the above-described CVD method from the direction in which rod-shaped body 54 protrudes.
At this time, a massive dense silicon carbide layer 510 is formed at the portion where the tip of the rod-like body 54 protrudes (see FIG. 5C).
That is, on the flat substrate portion 52 other than the vicinity of the rod-shaped body 54, silicon carbide crystals oriented in the (111) plane are stacked in the upward direction in the figure to form the dense silicon carbide layer 51. In the vicinity of the rod-shaped body 54, the rod-shaped body 54 protrudes from the surface of the base material portion 52, so that the orientation direction of the silicon carbide crystal is disturbed. As a result, the dense silicon carbide layer 510 formed in the vicinity of the rod-shaped body 54 has a large number of silicon carbide crystals oriented in the (220) plane.

Next, the surface of the dense silicon carbide layer 51 including the dense silicon carbide layer 510 and the rod-shaped body 54 is polished and subjected to a chamfering process so as to obtain a uniform surface (see FIG. 5D).

And it heats to about 800-1000 degreeC by oxygen containing atmosphere, and the through-hole 53 is formed by decomposing | disassembling and removing the rod-shaped body 54 (refer FIG.5 (e)).

By performing the above-described method, a dense silicon carbide layer in which more crystals oriented in the (220) plane are present in the periphery of the through hole than in portions other than the periphery of the through hole. can do.

It is desirable to chamfer the through-hole 13 manufactured in this way on the reactive gas blowing side. This is as described in the gas blowing plate of the present invention.

Furthermore, it is desirable to perform a post-treatment on the reaction gas blowing side of the dense silicon carbide layer 11 so that the thickness of the work brittle layer on the reaction gas blowing side of the dense silicon carbide layer 11 is 30 μm or less.

As the post-treatment, it is desirable to perform etching using an acidic etchant that can dissolve silicon carbide.
The etching solution is preferably a mixture of nitrous acid with a predetermined amount of weak acid.
Examples of the weak acid include organic acids such as acetic acid. An inorganic acid may be used as long as it satisfies the condition of a weak acid.

The composition of the etching solution is preferably hydrofluoric acid: nitric acid: acetic acid = 1: 2: 1 by weight. This is because only the work brittle layer can be surely dissolved and removed without eroding the dense silicon carbide layer present in the lower layer of the work brittle layer.

In this post-treatment, it is desirable to perform chemical polishing. This is because only the work brittle layer can be reliably and efficiently removed in a very short time.
Here, the chemical polishing refers to a process in which an etching process using an etchant made of fluoric acid having a weight ratio as described above and a surface polishing are performed in parallel. That is, when the chemical polishing is performed, a chemical dissolution action by the etching solution and a mechanical surface polishing action simultaneously act on the work brittle layer.

The chemical polishing is desirably performed for 0.5 to 5 minutes, more desirably for 1 to 5 minutes, and most desirably for 1 to 2 minutes.
If the execution time of chemical polishing is less than 0.5 minutes, the thickness of the work brittle layer may not be 30 μm or less, whereas if the execution time of chemical polishing exceeds 5 minutes, the work brittle layer Can be reliably reduced to 30 μm or less, but the influence of chemical polishing on the dense silicon carbide layer 11 below the work brittle layer may be exerted, and the dense silicon carbide layer 11 may be eroded. , Productivity decreases.

As described above, the gas blowing plate of the present invention in which the dense silicon carbide layer is formed on the base material portion as shown in FIG. 1 can be reliably manufactured by the method described above.

Moreover, the gas blowing plate as shown in FIG. 2 can be manufactured by performing the CVD method on the both surfaces of the base material portion as described above.
Furthermore, a dense silicon carbide layer is formed by a CVD method on a substrate having releasability, and then cutting is performed to cut out only the dense silicon carbide layer, and then a large number of through holes are formed. A gas blowing plate as shown in FIG. 3 can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) As a starting material for producing a base material portion made of porous silicon carbide, α-type silicon carbide coarse powder (# 400) having an average particle size of 30 μm and α-type silicon carbide fine powder (GMF) having an average particle size of 0.3 μm -15H2).
And 30 weight part of the said silicon carbide fine powder was mix | blended with respect to 100 weight part of the said silicon carbide coarse powder, and these were mixed uniformly.

After blending 5 parts by weight of polyvinyl alcohol, 3 parts by weight of phenol resin, and 50 parts by weight of water with 100 parts by weight of the mixture of the above silicon carbide coarse powder and silicon carbide fine powder, they are mixed in a ball mill for 5 hours. Thus, a uniform mixed composition was prepared.

After the mixed composition was dried for a predetermined time to remove moisture to some extent, an appropriate amount of a dried product of the mixed composition was collected and granulated using a spray drying method or the like. At this time, the moisture content of the granules was adjusted to about 0.8% by weight.

Subsequently, after putting the granule in a metal stamping die, it was molded at a press pressure of 130 MPa (1.3 t / cm ² ) using a molding machine using cold isostatic pressure (CIP) manufactured by Kobe Steel. A disc-shaped green sheet having a diameter of 420 mm and a thickness of 15 mm was produced.

Next, the green sheet was degreased by heating at 450 ° C. in a mixed gas atmosphere of air and nitrogen having a 5% oxygen concentration.

And the degreased body which passed through the said degreasing process was inserted into the graphite crucible, and it heated up to 2200 degreeC with the temperature increase rate of 10 degree-C / min in 1 atmosphere of argon gas atmosphere using a Tamman type baking furnace. And the base-material part which consists of porous silicon carbide was manufactured by hold | maintaining at this temperature for 4 hours.
The porosity of this base material portion was 40%.

(2) Formation of dense silicon carbide layer Drilling is performed so that 300 openings having a diameter of 0.5 mm are uniformly distributed on the surface of the base material portion in the manufactured base material portion. The carbon rod-like body was fitted so that one end thereof protruded by 3 mm.
Then, the surface from which the tip of the rod protrudes is set upward in a vacuum furnace for CVD, and after the pressure inside the furnace is reduced, SiCl ₄ gas and CCl ₄ gas are supplied at 1250 ° C. and 2.5 L / min. A plate-like body was manufactured by forming a dense silicon carbide layer (thickness 3 mm, impurity content 1 ppm or less) with high purity and density.
The ratio of the crystal orientation of the silicon carbide crystal constituting the dense silicon carbide layer is (111) plane: (220) plane = 1: 0.18 in the portion other than the peripheral portion of the rod-like body, and the rod-like shape At the periphery of the body, (111) plane: (220) plane = 1: 0.35.

Then, the surface of the dense silicon carbide layer including the tip portion of the protruding rod-like body was polished using a diamond grindstone.

Then, the carbon rod-shaped body was decomposed and removed by heating at 800 ° C. in an oxygen-containing atmosphere, and through holes were formed in the plate-shaped body.

Further, chemical polishing is performed on the surface of the dense silicon carbide layer on the reaction gas blowing side by using an etching solution made of fluoronitric acid (having a weight ratio of hydrofluoric acid: nitric acid: acetic acid = 1: 2: 1) as post-treatment. (Etching treatment time 1 minute), eliminating the processing brittle layer on the surface of the dense silicon carbide layer on the reaction gas blowing side, and the gas blowing plate of the present invention having a dense silicon carbide layer thickness of 2 mm Manufactured (see FIG. 1).
In the gas blowing plate according to Example 1, the surface roughness Ra according to JIS B 0601 of the surface of the dense silicon carbide layer was 0.01 μm.

The gas blowing plate according to Example 1 was set in a plasma etching apparatus as shown in FIG. 4 and used for 5 hours. Then, the gas blowing plate was taken out and the surface roughness Ra of the dense silicon carbide layer was measured. However, the surface roughness Ra of the peripheral part of the through hole was 0.03 μm, and the surface roughness Ra of the part other than the peripheral part of the through hole was 0.1 μm.
Further, no drop of silicon carbide particles is observed from the surface of the dense silicon carbide layer that has been directly exposed to the plasma, and the blowing direction and the blowing amount of the reactive gas blown into the plasma from the gas blowing plate are as follows: It was in a uniform and stable state. Furthermore, erosion by the plasma could be suppressed.

Example 2
A base material part was manufactured in the same manner as in Example 1, and carbon rods were fitted so as to protrude 3 mm from both sides of the through holes formed in the base material part, and the base material part was subjected to the same conditions as in Example 1. A dense silicon carbide layer was formed by performing CVD treatment on both sides of the substrate.
The crystal orientation of the silicon carbide crystal constituting this dense silicon carbide layer is (111) plane: (220) plane = 1: 0.18 in the portion other than the peripheral portion of the rod-shaped body. In the peripheral portion, (111) plane: (220) plane = 1: 0.35.
Thereafter, through-holes were formed in the same manner as in Example 1, and polishing with a diamond grindstone and chemical polishing were performed to manufacture a gas blowing plate having a dense silicon carbide layer with a thickness of 2 mm (see FIG. 2). ).
In the gas blowing plate according to Example 2, the surface roughness Ra according to JIS B 0601 of the surface of the dense silicon carbide layer was 0.01 μm.

After the gas blowing plate according to Example 2 was set in the plasma etching apparatus and used for 5 hours in the same manner as in Example 1, the gas blowing plate was taken out and the surface roughness Ra of the dense silicon carbide layer was measured. The surface roughness Ra of the peripheral part of the through hole was 0.03 μm, and the surface roughness Ra of the part other than the peripheral part of the through hole was 0.1 μm.
Further, no drop of silicon carbide particles is observed from the surface of the dense silicon carbide layer that has been directly exposed to the plasma, and the blowing direction and the blowing amount of the reactive gas blown into the plasma from the gas blowing plate are as follows: It was in a uniform and stable state. Furthermore, erosion by the plasma could be suppressed.

Example 3
An opening similar to the opening provided in the base material portion in Example 1 is provided in a disk-shaped graphite substrate, and one end of a carbon rod-like body is fitted into the opening so that 1.5 mm protrudes from the surface of the graphite substrate. did.
Next, a CVD treatment under the same conditions as in Example 1 was performed on the surface of the graphite substrate on the side where one end of the rod-shaped body protruded to form a dense silicon carbide layer having a thickness of 1.5 mm, and then the dense material By cutting the silicon carbide layer, a plate-like body consisting only of a dense silicon carbide layer having a diameter of 420 mm and a thickness of 1.5 mm was produced.
The crystal orientation of the silicon carbide crystal constituting this plate-like body is (111) plane: (220) plane = 1: 0.18 in the portion other than the peripheral portion of the rod-shaped body, and the peripheral portion of the rod-shaped body Then, (111) plane: (220) plane = 1: 0.35.
Thereafter, through holes were formed in the plate-like body in the same manner as in Example 1, and polishing with a diamond grindstone and chemical polishing were performed to manufacture a gas blowing plate made only of dense silicon carbide having a thickness of 1 mm ( (See FIG. 3).
In the gas blowing plate according to Example 3, the surface roughness Ra according to JIS B 0601 on the surface was 0.01 μm.

After the gas blowing plate according to Example 3 was set in the plasma etching apparatus and used for 5 hours in the same manner as in Example 1, the gas blowing plate was taken out and the surface roughness Ra of the surface was measured. The surface roughness Ra of the peripheral portion was 0.03 μm, and the surface roughness Ra of the portion other than the peripheral portion of the through hole was 0.1 μm.
Further, no drop of silicon carbide particles is observed from the surface of the dense silicon carbide layer that has been directly exposed to the plasma, and the blowing direction and the blowing amount of the reactive gas blown into the plasma from the gas blowing plate are as follows: It was in a uniform and stable state. Furthermore, erosion by the plasma could be suppressed.

Comparative Example 1
The surface of a plate-like body made of silicon having a diameter of 420 mm and a thickness of 10 mm was polished with a diamond grindstone, and then subjected to chemical polishing to produce a gas blowing plate made of silicon.
In the gas blowing plate according to Comparative Example 1, the surface roughness Ra of the surface according to JIS B 0601 was 0.01 μm.

After the gas blowing plate according to Comparative Example 1 was set in the plasma etching apparatus and used for 5 hours in the same manner as in Example 1, the gas blowing plate was taken out and the surface roughness Ra of the surface was measured. The surface roughness Ra of the peripheral portion was 0.2 μm, and the surface roughness Ra of the portion other than the peripheral portion of the through hole was 0.3 μm.
In addition, dropping of silicon particles was observed from the surface of the gas blowing plate that was continuously exposed to plasma, and particles were generated on the silicon wafer.

(A) is the perspective view which showed typically an example of the gas blowing plate of the plasma etching apparatus of this invention, (b) is a longitudinal cross-sectional view of the gas blowing plate shown to (a). (A) is the perspective view which showed typically another example of the gas blowing plate of the plasma etching apparatus of this invention, (b) is a longitudinal cross-sectional view of the gas blowing plate shown to (a). . (A) is the perspective view which showed typically another example of the gas blowing plate of the plasma etching apparatus of this invention, (b) is a longitudinal cross-sectional view of the gas blowing plate shown to (a). is there. It is sectional drawing which showed typically an example of the plasma etching apparatus which attached the gas blowing plate of this invention. (A)-(e) is sectional drawing which showed typically one process in the manufacturing method of the gas blowing board of the plasma etching apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gas blowing plate 11 Dense silicon carbide layer 12 Base material part 13 Through-hole

Claims (4)

A gas blowing plate of a plasma etching apparatus that constitutes a part of an electrode plate and allows a reaction gas to flow inside the electrode plate,
Many through holes are formed,
A gas blowing plate of a plasma etching apparatus, wherein a dense silicon carbide layer is formed at least on the surface on the side from which the reaction gas is blown. The gas blowing plate of the plasma etching apparatus according to claim 1, wherein crystals having different orientations are mixed in the dense silicon carbide layer. The peripheral part of the through-hole formed in the dense silicon carbide layer contains more crystals oriented in the (220) plane than parts other than the peripheral part of the through-hole. The gas blowing plate of the plasma etching apparatus. The gas blowing plate of the plasma etching apparatus according to any one of claims 1 to 3, wherein a chamfering is applied to a reactive gas blowing port of a through hole formed in the dense silicon carbide layer.

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