JP2003059903A - Gas blow-off plate of plasma etching apparatus, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas blow-off plate in a plasma etching apparatus which can prevent its surface erosion caused by plasma, can uniformly blow a reaction into the plasma, and can prevent the backflow of the plasma. SOLUTION: The gas blow-out plate in a plasma etching apparatus functions as an electrode and can pass a reaction gas therethrough into the interior thereof. The gas blow-off plate is made up of a porous silicon carbide layer having a multiplicity of air pores which are passed through the interior thereof and a dense silicon carbide layer having a multiplicity of through pores formed therein, which layers are integrally laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas blowing plate which constitutes a part of an electrode plate of a plasma etching apparatus which is a kind of semiconductor manufacturing apparatus, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, for example, a plasma etching apparatus has been known as a kind of semiconductor manufacturing apparatus using plasma. This apparatus exposes a silicon surface by exposing a silicon wafer that has undergone an exposure / development process to gas plasma to selectively remove only a photosensitive region of a photosensitive film.

A pair of positive and negative electrode plates are vertically separated from each other in a resin chamber constituting the plasma etching apparatus. A large 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. Further, on the upper surface of the lower electrode plate, a silicon wafer is arranged and fixed in a state of being fitted in the dummy ring.

Conventionally, a dense body of Si has been used for a gas blowing plate forming an upper electrode plate in a plasma etching apparatus.

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 chamber is placed in a vacuum state or a low pressure state. To fill the reaction gas. Next, after a plasma is generated by applying a high voltage between the upper and lower electrodes, a reaction gas is slowly blown into the chamber through a through hole formed inside the upper electrode plate to react with the generated plasma. The above silicon wafer is etched by blowing a gas onto the silicon wafer.

[0006] However, in such a plasma etching apparatus, since the gas blowing plate is a portion which comes into direct contact with the plasma, its surface is easily eroded, and the particles forming the upper electrode plate fall off and are deposited on the silicon wafer. The particles may adhere to each other and cause particles to be generated.

Then, on the surface of such an upper electrode plate,
It has been proposed to form a denser layer by a CVD method or the like to prevent the surface of the upper electrode plate from being eroded by plasma and generating particles on the silicon wafer. However, even with such an upper electrode plate, the reaction gas may not flow in a uniform state in the through hole because the through hole formed therein has a long length. In some cases, the blowing direction and blowing amount of the reaction gas blown to the wafer were not stable, and the silicon wafer could not be uniformly etched. Further, if the reaction gas flowing in the through hole is not in a uniform state, for example, the reaction gas flows into the plasma in the vicinity of the center of the through hole, but in the vicinity of the wall surface of the through hole, the plasma is in the through hole. The flow may be sucked into the interior of the through hole, and the plasma may flow back through the through hole to erode the upper electrode plate and members such as wiring provided thereon.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its surface is not eroded by plasma, and a reaction gas can be uniformly blown into the plasma. It is an object of the present invention to provide a blowing plate of a plasma etching apparatus capable of preventing backflow of plasma and a manufacturing method thereof.

[0009]

The gas blowing plate of the plasma etching apparatus of the present invention constitutes a part of the electrode plate,
A gas blowing plate of a plasma etching apparatus capable of circulating a reaction gas therein, wherein the gas blowing plate has a porous silicon carbide layer having a large number of communicating pores therein and a large number of through holes. It is characterized in that the formed dense silicon carbide layer is laminated and integrated.

Further, the method for manufacturing the gas blowing plate of the plasma etching apparatus of the present invention comprises a part of the electrode plate,
A method for manufacturing a gas blowing plate of a plasma etching apparatus capable of circulating a reaction gas therein,
A plurality of the above-mentioned flat plate portion of the T-shaped pin in which a flat plate is joined to one end of the rod-shaped body and / or one end portion of the rod-shaped pin are placed so as to be embedded in one main surface of the green sheet to be the porous silicon carbide layer. Then, the green sheet is fired in an inert atmosphere to produce a porous silicon carbide layer, and at least the T-shaped pin of the porous silicon carbide layer and / or
Alternatively, a layered body manufacturing step of manufacturing a layered body by forming a dense silicon carbide coating body by a chemical vapor deposition method on the surface on which the rod-shaped pin is formed, and a surface of the dense silicon carbide coating body. A polishing step of exposing a part of the T-shaped pin and / or the rod-shaped pin by polishing and forming a dense silicon carbide layer, and heating the polished laminated body in an oxidizing atmosphere And a disassembly and removal step of disassembling and removing the T-shaped pin and / or the rod-shaped pin. Hereinafter, the present invention will be described in detail.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION First, a gas blowing plate of a plasma etching apparatus of the present invention will be described. The gas blowing plate of the plasma etching apparatus of the present invention constitutes a part of the electrode plate, and is a gas blowing plate of the plasma etching apparatus capable of circulating a reaction gas therein, wherein the gas blowing plate is It is characterized in that a porous silicon carbide layer having a large number of communicating pores therein and a dense silicon carbide layer having a large number of through holes are laminated and integrated.

FIG. 1 (a) is a perspective view schematically showing a gas blowing plate of the plasma etching apparatus of the present invention (hereinafter, also referred to as a gas blowing plate of the present invention), and FIG.
[FIG. 4] is a partially enlarged cross-sectional view of the gas blowing plate shown in (a), and (c) is a partially enlarged cross-sectional view schematically showing a gas blowing plate in which a cavity is provided in a porous silicon carbide layer.

As shown in FIG. 1A, the gas blowing plate 10 of the present invention has a disk-shaped dense silicon carbide layer 12 in which a large number of through holes 13 are formed, and also has a disk-shaped structure. Porous silicon carbide layer 11 is laminated and integrated.

The diameter of the porous silicon carbide layer 11 is appropriately determined according to the diameter of the object to be processed such as a silicon wafer.
Specifically, it is desirable that it is about 200 to 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 a silicon wafer. On the other hand, if it exceeds 500 mm, it is possible to sufficiently cope with the recent increase in the diameter of silicon wafers, but since the plasma etching apparatus also 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 perform a uniform etching process on the silicon wafer. The diameter of the porous silicon carbide layer 11 is 30
More preferably, it is 0 to 500 mm. This is to support the next-generation mainstream silicon wafers of 12 inches or larger.

Further, the thickness of the porous silicon carbide layer 11 is not particularly limited, and it is usually desirable to be 2 to 30 mm. When the thickness is less than 2 mm, the porous silicon carbide layer 11
Warp is liable to occur, and its mechanical strength is lowered, and cracks are apt to occur. On the other hand, the thickness is 30 mm
When it exceeds, the reaction gas becomes difficult to flow, the pressure loss increases, and the gas blowing plate 10 and the like may be damaged.

The porosity of the porous silicon carbide layer 11 is 3
It is preferably 0 to 50%. If the porosity is less than 30%, it becomes difficult for the reaction gas to flow through the inside, so that the pressure loss increases and the gas blowing plate 10 and the like may be damaged. On the other hand, when the porosity exceeds 50%, the mechanical strength of the porous silicon carbide layer 11 is weakened, and thus cracks are likely to occur, and the silicon carbide particles are likely to drop off.

Further, in the gas blowing plate of the present invention, the portion of the porous silicon carbide layer that comes into contact with the through hole formed in the dense silicon carbide layer has the same cross-sectional area as the above through hole or the above. It is desirable that a cavity having a cross-sectional area larger than the cross-sectional area of the through hole be formed. The reason for this will be described in the method of manufacturing a gas blowing plate of the plasma etching apparatus of the present invention described later. In addition, as shown in FIG. 1C, a cross-sectional area larger than the cross-sectional area of through-hole 13 is formed in a portion of porous silicon carbide layer 11 that is in contact with through-hole 13 formed in dense silicon carbide layer 12. If the voids 14 are formed, most of the silicon carbide particles will be formed even if the silicon carbide particles forming the porous silicon carbide layer 11 are dropped.
By depositing on the upper surface of the dense silicon carbide layer 12 facing the cavity 14, the silicon carbide particles can be prevented from passing through the through holes 13 and adhering to the silicon wafer.

Further, it is desirable that the silicon carbide particles forming the porous silicon carbide 11 have a size such that they cannot pass through the through holes 13 formed in the dense silicon carbide layer 12. This is because even if the silicon carbide particles fall off from the porous silicon carbide layer 11, the silicon carbide particles can be reliably prevented from adhering to the silicon wafer through the through holes 13.

The diameter of the dense silicon carbide layer 12 is preferably the same as the diameter of the porous silicon carbide layer 11 described above, and its thickness is preferably 0.2 to 5 mm.
If the thickness of the dense silicon carbide layer 12 is less than 0.2 mm, the porous silicon carbide layer 11 is immediately abraded by the plasma, so that the porous silicon carbide layer 11 is exposed to the plasma, and the silicon carbide particles fall off. I may end up doing it. On the other hand, if the thickness of the dense silicon carbide layer 12 exceeds 5 mm, the thickness is sufficient, and if the dense silicon carbide layer 12 is thicker than this, it is disadvantageous in terms of time and cost.

Such a dense silicon carbide layer 12 is formed on the surface of the porous silicon carbide layer 11 by chemical vapor deposition (hereinafter, CV).
The coating layer is preferably formed by the method D). This is because a dense silicon carbide layer can be reliably formed on the porous silicon carbide layer 11.

Further, an impregnated layer impregnated with silicon carbide is formed in the vicinity of the surface of the porous silicon carbide layer 11 which is in contact with the dense silicon carbide layer 12, and the through holes 13 are dense. It is preferably formed so as to penetrate silicon carbide layer 12 and the impregnated layer. This is because by forming the impregnated layer on the porous silicon carbide layer 11, the adhesive strength between the porous silicon carbide layer 11 and the dense silicon carbide layer 12 becomes extremely strong. If the through holes 13 formed in the silicon layer 12 are not formed so as to penetrate the impregnated layer, the reaction gas flowing through the porous silicon carbide layer 11 is blocked by the impregnated layer and plasma is generated. Because it will not be possible to blow it inside.

The thickness of the impregnated layer is preferably 10 to 30 μm. When it is less than 10 μm, the adhesive strength between the porous silicon carbide layer 11 and the dense silicon carbide layer 12 hardly improves, while when it exceeds 30 μm, the porous silicon carbide layer 11 and the dense silicon carbide layer The adhesive strength with 12 is sufficient, and conversely, it takes a long time to form such a thick impregnated layer, which is disadvantageous in terms of time and cost.

A large number of through holes 13 formed in dense silicon carbide layer 12 are formed so as to be uniformly distributed on the main surface of dense silicon carbide layer 12. This is because the reaction gas flowing through the porous silicon carbide layer 11 can be uniformly blown into the plasma.

The diameter of such a through hole 13 is not particularly limited, but it is usually desirable to be 0.1 to 1 mm. If the diameter of the through holes 13 is less than 0.1 mm, clogging is likely to occur, and the reaction gas may not be blown into the plasma in a uniform blowing direction and blowing amount. On the other hand, the diameter of the through hole 13 is 1 m.
When it exceeds m, when the silicon carbide particles forming the porous silicon carbide layer 11 drop off, the dropped silicon carbide particles easily pass through the through holes 13, and the silicon carbide particles adhere to the silicon wafer. I may end up doing it.

Further, it is desirable that the reaction gas outlet of the through hole 13 is chamfered. This is because if the reaction gas outlet of the through hole 13 is angular, plasma is likely to intensively hit this portion, the reaction gas outlet 0 is corroded, and the silicon carbide particles are likely to drop off.

The chamfer may be a C chamfer,
It may be rounded. When the chamfer is C chamfer, the chamfer width and height are preferably 0.1 to 1 mm, and when the chamfer is R chamfer, the radius of the curved surface is preferably 0.1 to 1 mm. .

If the chamfer width and height of C chamfer and the radius of the curved surface of R chamfer are less than 0.1 mm, the through hole 13
The reaction gas outlet is in an angular state, plasma is likely to intensively hit the reaction gas outlet, and the silicon carbide particles may drop off. On the other hand, the chamfer width and height of C chamfer and the radius of the curved surface of R chamfer are 1 m.
When it exceeds m, the diameter of the through hole 13 on the side facing the plasma becomes large, the plasma easily enters the through hole 13, and the backflow of the plasma easily occurs.

In addition, Si, C of the dense silicon carbide layer 12,
The content of impurities other than O, N, and Y is preferably 5 ppm or less. When the content of the impurities exceeds 5 ppm, the dense silicon carbide layer 12 is gradually abraded by the plasma, and the impurities are diffused into the plasma and adhered to the silicon wafer, and the purity thereof deteriorates. I will end up.

Further, it is desirable that the work-brittle layer of the dense silicon carbide layer 12 on the reaction gas blowing side has a thickness of 30 μm or less. When the thickness of the working brittle layer exceeds 30 μm, the working brittle layer is directly exposed to plasma,
The silicon carbide particles in the work-brittle layer may easily fall into plasma and adhere to the silicon wafer. A detailed method for making the working brittle layer of the dense silicon carbide layer 12 on the reaction gas blowing side a thickness of 30 μm or less will be described in detail in a method for manufacturing a gas blowing plate of a plasma etching apparatus of the present invention described later. To do.

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

FIG. 2 is a 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. 2, the plasma etching apparatus 20 is provided in the chamber 24 and in the vicinity of the center of the upper surface of the chamber 24, and includes the gas blowing plate 10 and the upper electrode plate 22.
And a dummy ring 2 provided near the center of the lower surface inside the chamber 24.
8 and a lower electrode plate 25 for mounting the silicon wafer 19 fitted therein.

The upper electrode plate 22 and the lower electrode plate 25 are electrically connected to an AC power source, respectively. By applying a voltage to the upper electrode plate 22 and the lower electrode plate 25, the upper electrode plate 22 and the lower electrode plate 25 are electrically connected. A gas plasma 200 can be generated between the plate 22 and the lower electrode plate 25.

The chamber 24 is a container for performing a plasma etching process on the silicon wafer 19, and is usually
The shape thereof is a column, but if the gas blowing plate 10, the upper electrode plate 22, the lower electrode plate 25, the silicon wafer 19 and the like can be housed therein, the chamber 24 can be housed.
May have any shape such as a prismatic shape or an elliptic cylindrical shape. Further, an exhaust port 23 for evacuating the chamber 24 and exhausting reaction gas and the like to the outside is provided on a part of the lower surface of the chamber 24. The exhaust port 23 is provided on the bottom surface of the chamber 24, but may be formed on the side surface of the chamber 24, for example. Further, the chamber 24 may be formed of one member, but may be formed by joining a plurality of members to each other as long as the airtightness of the inside can be ensured.

The gas blowing plate supporting member 26 has an opening formed in the lower surface thereof, and the upper electrode plate 22 is formed in the opening.
Also, the gas blowing plate 10 can be fitted and fixed. In addition, the blowing plate support member 26
A supply pipe 26a is formed on the upper surface of the so that the reaction gas and the like can be supplied to the upper electrode plate 22 and the gas blowing plate 10. Such a gas blowing plate support member 26 is fixed to the inner wall surface of the upper portion of the chamber 24, and the upper electrode plate 22 and the gas blowing plate 10 fixed to the opening of the lower surface thereof are arranged inside the chamber 24. On the other hand, the supply pipe 26a formed on the upper surface thereof is arranged outside the chamber 26.

As the upper electrode plate 22 and the lower electrode plate 25, the same electrode plates used in the conventionally known plasma etching apparatus can be used, but the upper electrode plate 2
2 has a structure in which a reaction gas can be circulated therein. As such an upper electrode plate 22,
For example, a structure in which a large number of through holes are provided in the thickness direction, or a large number of concentric circular grooves are formed on the surface on the gas blowing plate 10 side, and the bottom surface of these grooves and the opposite side of the gas blowing plate 10 are formed. For example, a structure having a large number of through holes penetrating the surface may be used. The diameters of the upper electrode plate 22 and the lower electrode plate 25 are preferably at least the same as the diameter of the silicon wafer 19. This is because plasma is generated at least in the space directly above the silicon wafer 19.

A fitting recess for fitting the silicon wafer 19 is provided at the center of the upper surface of the dummy ring 28. By fitting the silicon wafer 19 in the fitting recess, the bottom surface of the silicon wafer 19 is fitted. The outer peripheral portion is supported over the entire circumference to prevent the silicon wafer 19 from moving during the plasma etching process. Although not shown, the dummy ring 28 is provided with a driving mechanism so that the dummy ring 28 can move in the vertical direction together with the silicon wafer 19 within a predetermined range. That is, by changing the distance from the gas blowing plate 10 to the silicon wafer 19, the irradiation condition of the gas plasma 200 can be adjusted appropriately.

In order to perform plasma etching on the silicon wafer 19 using the plasma etching apparatus 20 as described above, first, the respective members are arranged as described above. Then, the inside of the chamber 24 is brought into a vacuum or low pressure state, and the supply pipe 2
After the reaction gas is filled in the chamber 24 from 6a through the upper electrode plate 22 and the gas blowing plate 10, a voltage is applied to the upper electrode plate 22 and the lower electrode plate 25, and the gas plasma 200 is generated between them. generate. Next, the supply pipe 26
The reaction gas is slowly supplied from a, and the blowing plate support member 26
Then, the reaction gas is blown into the chamber 24 through the upper electrode plate 22 and the gas blowing plate 10.
Then, the gas plasma 200 moves on the silicon wafer 19 along with the flow of the blown out reaction gas, so that the silicon wafer 19 is subjected to the plasma etching process.

As described above, the gas blowing plate of the present invention is
A porous silicon carbide layer having a large number of communicating pores therein and a dense silicon carbide layer having a large number of through holes are laminated and integrated. That is, in the plasma etching apparatus equipped with the gas blowing plate of the present invention, the reaction gas which has flowed through the pores in the porous silicon carbide layer passes through the through-holes formed in the dense silicon carbide layer to cause plasma in the plasma. It is blown out to. Therefore, the dense silicon carbide layer is formed on the surface of the reaction gas blowing side most exposed to plasma, is not easily eroded by the plasma, and there are almost no silicon carbide particles that fall off. Further, since the reaction gas is sufficiently diffused while flowing through the pores in the porous silicon carbide layer, it is introduced into the through holes of the dense silicon carbide layer in a uniform state, and is introduced into the plasma. The blowing direction and the blowing amount of the above reaction gas are uniform and stable. further,
Since the through hole formed in the dense silicon carbide layer has a short length, the flow of the reaction gas is not disturbed in the through hole, and the reverse flow of plasma is not generated.

Next, a method of manufacturing the gas blowing plate of the plasma etching apparatus of the present invention will be described. A method of manufacturing a gas blowing plate of a plasma etching apparatus of the present invention is a method of manufacturing a gas blowing plate of a plasma etching apparatus, which constitutes a part of an electrode plate and allows a reaction gas to flow inside thereof, After placing a plurality of the flat plate portions of the T-shaped pins and / or one end portions of the rod-shaped pins in which a flat plate is joined to one end of the body so as to be embedded in one main surface of the green sheet to be the porous silicon carbide layer A firing step of producing a porous silicon carbide layer by firing the green sheet in an inert atmosphere, and at least a surface of the porous silicon carbide layer on which the T-shaped pin and / or the rod-shaped pin is formed. A layered body manufacturing step of manufacturing a layered body by forming a dense silicon carbide coating on the upper side by a chemical vapor deposition method, and polishing the surface of the dense silicon carbide coated body to form the T-shaped pin. And / or to expose a portion of the rod-shaped pin, a polishing step to produce a dense silicon carbide layer,
And a decomposition and removal step of heating the polishing-processed laminate in an oxidizing atmosphere to decompose and remove the T-shaped pin and / or the rod-shaped pin.

3 (a) to 3 (d) are cross-sectional views schematically showing one step in the method for producing a gas blowing plate of the plasma etching apparatus of the present invention (hereinafter, also simply referred to as the production method of the present invention). It is a figure. In the following description, the pin to be placed on the green sheet is described as a T-shaped pin in which a flat plate is joined to one end of a rod-shaped body, but in the manufacturing method of the present invention, the pin is placed on the green sheet. The shape of the pin to be placed is not limited to this, for example,
It may be a prismatic rod or a cylindrical rod-shaped pin.

In the manufacturing method of the present invention, first, the flat plate portion of the T-shaped pin 130 in which a flat plate is joined to one end of the rod-shaped body is embedded in one main surface of the green sheet 110 which becomes the porous silicon carbide layer. A plurality of them are placed on the substrate (FIG. 3 (a)).

To produce the green sheet 110, first, a mixed composition containing silicon carbide powder, a binder, and a dispersion medium liquid is prepared. The particle size of the silicon carbide powder is
It is desirable that the shrinkage in the subsequent firing step is small, for example,
A combination of 100 parts by weight of silicon carbide powder having an average particle size of about 0.3 to 50 μm and 5 to 65 parts by weight of silicon carbide powder having an average particle size of about 0.1 to 1.0 μm is desirable.

Examples of the binder include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, polyvinyl alcohol, phenol resin, epoxy resin, acrylic resin and the like. Usually, the amount of the binder blended is preferably 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, the binder, etc. is within a certain range.

In addition to the silicon carbide powder, the binder and the dispersion medium liquid, a dispersant may be contained. The dispersant is not particularly limited, and examples thereof include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris (2-chloroethyl) phosphate,
Examples thereof include phosphoric acid ester compounds such as triphenyl phosphate, tricresyl phosphate, and cresyl diphenyl phosphate. Further, 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 above-mentioned mixed composition is prepared by mixing the above-mentioned silicon carbide powder, binder, dispersion medium liquid and the like with a vibration mill, an attritor, a ball mill, a colloid mill, a high speed mixer or the like, and then thoroughly kneading them with a kneader or the like. can do.

Next, the mixed composition is granulated by a spray drying method or the like and then press-molded by cold isostatic pressure (CIP) to mold it into a predetermined shape to produce a green sheet 110. The green sheet 110 may be manufactured by an extrusion molding method, a doctor blade method, or the like.

The T-shaped pin 130 is a member for forming the through hole 13 of the dense silicon carbide layer 12 and the cavity 14 on the surface of the porous silicon carbide layer 11 which is in contact with the through hole 13. Yes, the diameter of the flat plate portion of the T-shaped pin 130 is
The diameter of the rod-shaped body of the T-shaped pin 130 is the same as that of the cavity 14 in the gas blowing plate of the present invention described above.
It has the same diameter as the diameter of the through hole 13. Further, the length of the rod-shaped body may be longer than the thickness of dense silicon carbide layer 12. This is because the through holes 13 are formed in the dense silicon carbide layer 12 manufactured through the subsequent steps. The T-shaped pin 13
The flat plate of 0 is not limited to a circular plate, and may be a polygonal plate in plan view. Further, it is desirable that carbon is used as a material forming the T-shaped pin 130. In addition, T
When a rod-shaped pin such as a column or a prism is used in place of the V-shaped pin 130, its size is preferably the same as the rod-shaped body of the T-shaped pin 130, and its material is also the T-shaped pin 13.
It is desirable that the same as 0.

Further, the number of T-shaped pins 130 is not particularly limited, and is appropriately adjusted according to the diameter of the porous silicon carbide layer or the silicon wafer. The T-shaped pins 130 are preferably placed on the surface of the green sheet 110 so as to be uniformly distributed. This is because the through holes formed in the gas blowing plate 10 to be manufactured are evenly distributed on the main surface of the gas blowing plate so that the plasma etching process of the silicon wafer can be uniformly performed.

Next, the green sheet 110 on which the T-shaped pin 130 is placed is degreased. For the degreasing, the green sheet 110 is set to 400 in an atmosphere containing oxygen.
It is desirable to carry out by heating to ˜650 ° C.
Most of the binder and the like contained in the green sheet 110 are volatilized and decomposed and eliminated, while a plurality of T
The V-shaped pin 130 can be left on the surface of the green sheet 110 without being decomposed.

Then, a firing step of firing the degreased green sheet 110 in an inert atmosphere is carried out,
The porous silicon carbide layer 11 is manufactured.

In the firing step, the inert atmosphere is not particularly limited, and examples thereof include a gas atmosphere of at least one selected from nitrogen, argon, helium, neon, hydrogen and carbon monoxide. The inside of the firing furnace may be in a vacuum state. Further, the firing temperature is preferably 1700 to 2400 ° C, more preferably 2000 to 2400 ° C,
Most preferably, it is 2000 to 2300 ° C. If the firing temperature is less than 1700 ° C., it becomes difficult to sufficiently develop the neck portion that bonds the silicon carbide particles to each other,
It may not be possible to achieve high thermal conductivity and high strength. On the other hand, if the firing temperature exceeds 2400 ° C., thermal decomposition of silicon carbide will start and the strength of the sintered body will decrease. Also, the amount of heat energy required for firing increases,
It is a cost disadvantage.

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

Next, at least the porous silicon carbide layer 11
On the surface on which the T-shaped pin 130 is formed, a laminated body manufacturing step is performed in which a dense silicon carbide coating body 120 is formed by a chemical vapor deposition method (CVD method) to form a laminated body.

The CVD method is preferably a low pressure CVD method. In addition to being suitable for mass production,
This is because even if the porous silicon carbide layer 11 does not have a simple shape, the dense silicon carbide coating body 120 can be surely laminated.

In the above CVD method, a silicon-containing gas and a carbon-containing gas are reacted on the surface of the vapor phase or porous silicon carbide layer 11, or a gas containing silicon and carbon at the same time is vapor phase or porous carbonized. By reacting on the surface of the silicon layer 11, the dense silicon carbide coating 120 is laminated on the porous silicon carbide layer 11 (FIG. 3B).

The silicon-containing gas is not particularly limited, and examples thereof include SiCl ₄ gas and SiH ₂ Cl ₂ gas. Further, the carbon-containing gas is not particularly limited and includes, for example, CCl ₄ gas. , C ₂ H ₂ gas, and the like. The gas containing silicon and carbon at the same time is not particularly limited, and examples thereof include trichloromethylsilane (CH ₃ SiCl ₃ ).

The processing temperature at this time is 1000 to 1
It is preferably 700 ° C. This is because the dense silicon carbide coated body 120 can be uniformly laminated and formed. The thickness of the dense silicon carbide coating body 120 formed under such conditions is preferably about the same as the length of the rod-shaped body of the T-shaped pin 130.

Further, it is desirable that an impregnation layer impregnated with silicon carbide is formed in the vicinity of the surface of porous silicon carbide layer 11 in contact with dense silicon carbide coating 120. The impregnated layer preferably has a thickness of 10 to 30 μm.

In the dense silicon carbide coated body 120 laminated and formed on the porous silicon carbide layer 11 in this manner, it is desirable that the average particle diameter of the silicon carbide particles is 1 to 20 μm. Si contained in 120,
The content of impurities other than C, O, N, and Y is preferably 5 ppm or less.

Next, the surface of the dense silicon carbide coating body 120 is polished to expose a part of the T-shaped pin 130, and a polishing step of forming the dense silicon carbide layer 12 is performed.

The method of polishing the surface of the dense silicon carbide coating 120 is not particularly limited, and any method such as a grindstone or sandpaper can be used. The dense silicon carbide layer 12 thus manufactured has a thickness of 0.2.
It is desirable that it is ˜5 mm. The end of the rod-shaped body of the T-shaped pin 130 is exposed on the polished surface of the dense silicon carbide layer 12 to be formed (FIG. 3C).

Then, the above-mentioned laminated body subjected to the polishing treatment is heated in an oxidizing atmosphere to carry out a decomposition / removal step in which the T-shaped pin 130 is decomposed and removed.

The heating temperature in the above decomposition and removal step is T
The temperature may be any temperature at which the V-shaped pin 130 can be decomposed and removed. For example, when the T-shaped pin 130 is made of carbon, the temperature is preferably 500 to 1300 ° C. When the heating temperature is less than 500 ° C, the T-shaped pin 13
0 may not be completely decomposed and removed. On the other hand, if the heating temperature exceeds 1300 ° C., the temperature is sufficient to decompose and remove the T-shaped pin 130. Will be disadvantageous.

By carrying out this decomposition and removal step, through holes 13 can be formed in dense silicon carbide layer 12 and cavities 14 can be formed in portions of porous silicon carbide layer 11 that are in contact with through holes 13. (FIG.3 (d)). In addition, T
When a rod-shaped pin such as a cylinder or a prism is used instead of the V-shaped pin 130, the cross-sectional area of the cavity formed in the porous silicon carbide layer and the cross-sectional area of the through hole formed in the dense silicon carbide layer. Will be the same.

It is desirable to chamfer the end (reaction gas outlet) of the through hole 13 of the dense silicon carbide layer 12 thus manufactured, which is opposite to the cavity 14. This is as described for the gas blowing plate of the present invention.

Further, the reaction gas blowing side surface of the dense silicon carbide layer 12 may be subjected to post-treatment so that the work brittle layer on the reaction gas blowing side of the dense silicon carbide layer 12 has a thickness of 30 μm or less. desirable.

As the above post-treatment, it is desirable to carry out etching using an acidic etching solution capable of dissolving silicon carbide. The etching solution is preferably a mixture of hydrofluoric nitric acid and a predetermined amount of a 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 it is possible to surely dissolve and remove only the work-brittle layer without eroding the dense silicon carbide layer existing under the work-brittle layer.

In this post-treatment, it is desirable to carry out chemical polishing. This is because only the work brittle layer can be removed reliably and efficiently in an extremely short time. Here, the chemical polishing refers to a process in which an etching process using an etching solution composed of hydrofluoric nitric acid with a weight ratio as described above and a surface polishing process are performed in parallel. That is, when the chemical polishing is carried out, the working brittle layer is simultaneously subjected to a chemical dissolution action by the etching solution and a mechanical surface polishing action.

The above chemical polishing is 0.5 to 5
It is desirable to carry out for 1 minute, more desirably for 1 to 5 minutes, and most desirably for 1 to 2 minutes. If the chemical polishing time is less than 0.5 minutes, the thickness of the work brittle layer may not be 30 μm or less. On the other hand, if the chemical polishing time is more than 5 minutes, the work brittle layer may not be formed. Can be reliably set to 30 μm or less, but the influence of chemical polishing extends to the dense silicon carbide layer 12 below the work-brittle layer.
The dense silicon carbide layer 12 may be eroded and the productivity may be reduced.

As described above, according to the manufacturing method of the present invention, a dense silicon carbide layer having a large number of through holes formed on the surface of the porous silicon carbide layer is laminated to form the porous silicon carbide layer. It is possible to manufacture a gas blowing plate in which a cavity having a cross-sectional area that is the same as the cross-sectional area of the through-hole or larger than the cross-sectional area of the through-hole is formed in the portion that contacts the through-hole. Further, the plasma etching apparatus provided with the gas blowing plate according to the manufacturing method of the present invention can obtain the same effect as that of the gas blowing plate of the present invention described above. Furthermore, when a rod-shaped pin such as a cylinder or a prism is used when manufacturing the gas blowing plate, the cross-sectional area of the cavity is the same as the cross-sectional area of the through hole, while the gas blowing plate is manufactured. When a T-shaped pin is used for the above, the cross-sectional area of the cavity becomes larger than the cross-sectional area of the through hole, but in any case, the through hole is formed in the dense silicon carbide layer. It is possible to form uniform through-holes at a time without the need for machining or the like when forming. In the manufacturing method of the present invention, a cavity having a cross-sectional area larger than the cross-sectional area of the through hole is formed in a portion of the porous silicon carbide layer that contacts the through-hole of the dense silicon carbide layer by using a T-shaped pin. Then, even when the silicon carbide particles are dropped off in the porous silicon carbide layer, the dropped silicon carbide particles are deposited on the upper surface of the dense silicon carbide layer in the cavity,
The silicon carbide particles can be prevented from adhering to the silicon wafer through the through holes.

[0073]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 (see FIG. 3) (1) Production of porous silicon carbide layer As starting materials, α-type silicon carbide coarse powder (# 400) having an average particle diameter of 30 μm and α having an average particle diameter of 0.3 μm Type silicon carbide fine powder (GMF-15H2) was prepared. Then, 30 parts by weight of the above silicon carbide fine powder was mixed with 100 parts by weight of the above silicon carbide coarse powder, and these were uniformly mixed.

5 parts by weight of polyvinyl alcohol, 3 parts by weight of phenolic resin and 50 parts by weight of water were added to 100 parts by weight of the mixture of the above-mentioned coarse powder of silicon carbide and fine powder of silicon carbide, and then mixed in a ball mill. A uniform mixed composition was prepared by mixing for a period of time.

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

Next, after putting the above granules in a metal pressing die, a pressing pressure of 130 MPa (1.3 t / cm ² ) was applied using a molding machine using cold isostatic pressure (CIP) manufactured by Kobe Steel. Then, a disk-shaped green sheet 110 having a diameter of 420 mm and a thickness of 10 mm was produced.

Next, made of carbon, the flat plate portion has a diameter of 5 m.
m, thickness 1 mm, diameter of rod-shaped body 0.5 mm, length 5 mm
300 T-shaped pins 130, green sheet 110
The flat plate portion was embedded and placed so as to be uniformly distributed on the surface.

Next, the green sheet 110 provided with the T-shaped pins 130 was heated at 450 ° C. in a mixed gas atmosphere of air and nitrogen having an oxygen concentration of 5% to degrease the green sheet 110. .

Then, the degreased body that has undergone the above degreasing process is placed in a graphite crucible and
Porous silicon carbide layer 11 was manufactured by raising the temperature to 2200 ° C. at a temperature rising rate of 10 ° C./min in an argon gas atmosphere at atmospheric pressure and maintaining this temperature for 4 hours. The porosity of this porous silicon carbide layer 11 was 40%.

(2) Formation of dense porous layer The T-shaped pin 130 of the porous silicon carbide layer 11 produced above.
The surface on which the film was formed is set upward and set in a vacuum furnace for CVD, and the inside of the furnace is depressurized, then SiCl ₄ gas and C are added.
A Cl ₄ gas was circulated to form a dense and dense dense silicon carbide laminate 120 (thickness: 4 mm, impurity content: 1 ppm or less), thereby producing a laminate.

Then, the surface of the dense silicon carbide laminated body 120 of the laminated body is polished by using a diamond grindstone,
A dense silicon carbide layer 12 having a thickness of 3 mm was formed. In addition,
The T-shaped pin 1 is formed on the polished surface of the dense silicon carbide layer 12.
The end of 30 rod-shaped bodies was exposed.

Thereafter, the above laminated body was subjected to an oxygen-containing atmosphere,
By heating at 800 ° C., the T-shaped pin 130 was decomposed and removed, the cavity 14 was formed in the porous silicon carbide layer 11, and the through hole 13 was formed in the dense silicon carbide layer 12.

On the surface of the dense silicon carbide layer 12 which becomes the reaction gas blowing side surface, as an after-treatment, an etching solution containing fluoronitrate acetic acid (weight ratio of hydrofluoric acid: nitric acid: acetic acid = 1: 2: 1) was used. Using this, chemical polishing was performed (etching time: 1 minute) to eliminate the work-brittle layer on the surface of the dense silicon carbide layer 12 which becomes the reaction gas blowing side surface, to manufacture the gas blowing plate of the present invention.

When the obtained gas blowing plate was actually set and used in the plasma etching apparatus as shown in FIG. 2, the silicon carbide particles did not fall off from the surface of the dense silicon carbide layer directly exposed to plasma. It was not observed at all, and the blowing direction and blowing amount of the reaction gas blown into the plasma from the gas blowing plate were in a uniform and stable state. Furthermore, the erosion due to the above plasma could be suppressed.

Comparative Example 1 First, with respect to 100 parts by weight of silicon carbide powder having an average particle size of 50 μm, 7 parts by weight of a phenol resin, 1 part by weight of an acrylic resin (Ricabond manufactured by Chuo Rika Kogyo Co., Ltd.), and 50 parts by weight of water were mixed. After that, a uniform mixed composition was obtained by mixing in a ball mill for 5 hours. After the mixed composition was dried for a predetermined time to remove water to some extent, an appropriate amount of the dried mixed composition was sampled and granulated by a spray drying method or the like. At this time, the water content of the granules was adjusted to be about 0.8% by weight.

Next, using a dryer, the heating temperature is 80 ° C.,
The above granules were heat-treated under the condition that the heating time was 5 hours. Then, after putting the granules of the above-mentioned mixed composition in a mold, using a molding machine utilizing cold isostatic pressure (CIP) manufactured by Kobe Steel, holding the pressure at 96 MPa for 30 seconds, the diameter 42
A disk-shaped silicon carbide molded body having a thickness of 0 mm and a thickness of 10 mm was formed.

Next, the silicon carbide molded body is carried into a degreasing furnace and heated at 600 ° C. for 2 hours in a mixed gas atmosphere of air and nitrogen having an oxygen concentration of 5% to degrease the silicon carbide molded body. I went.

Next, the degreased silicon carbide compact was charged into a graphite crucible and held at 1800 ° C. for 4 hours in an argon atmosphere of 1 atm using a Tammann type firing furnace to obtain the above. By firing the degreased silicon carbide molded body, a disc-shaped dense silicon carbide substrate was manufactured.

Next, the silicon carbide substrate is set in a vacuum furnace for CVD, the inside of the furnace is decompressed, and then SiCl.
₄ gas and CCl ₄ gas were circulated to form a highly pure and dense silicon carbide layer (thickness: 4 mm, impurity content: 1 ppm or less). The silicon carbide particles forming the silicon carbide layer had an average particle size of 7 μm and a maximum particle size of 30 μm.

Then, after forming a plurality of through holes penetrating the silicon carbide substrate and the silicon carbide layer by drilling, the surface of the silicon carbide layer was subjected to chemical polishing under the same conditions as in Example 1. A gas blowing plate was manufactured.

When the obtained gas blowing plate was set in a plasma etching apparatus and used in the same manner as in Example 1, the silicon carbide particles did not fall off from the surface of the silicon carbide layer formed by the CVD method that was directly exposed to plasma. Although not observed, the reaction gas blown into the plasma from the gas blowing plate was not stable and did not become a uniform state. Further, it was observed that the above-mentioned plasma flows backward in the through hole provided so as to penetrate the silicon carbide substrate and the silicon carbide layer.

[0093]

As described above, according to the gas blowing plate of the present invention, the surface of the gas blowing plate is not eroded by the plasma, so that the particles are not dropped and the reaction gas is uniformly blown into the plasma. While being able to
The reverse flow of plasma can be prevented.

Further, according to the method for manufacturing a gas blowing plate of the present invention, since the surface thereof is not corroded by plasma, particles do not fall off, and the reaction gas can be uniformly blown into the plasma. At the same time, it is possible to reliably manufacture the gas blowing plate capable of preventing the reverse flow of plasma.

[Brief description of drawings]

FIG. 1A is a perspective view schematically showing a gas blowing plate of a plasma etching apparatus of the present invention, and FIG.
[FIG. 4] is a partially enlarged cross-sectional view of the gas blowing plate shown in (a), and (c) is a partially enlarged cross-sectional view schematically showing a gas blowing plate in which a cavity is provided in a porous silicon carbide layer.

FIG. 2 is a cross-sectional view schematically showing an example of a plasma etching apparatus equipped with a gas blowing plate of the present invention.

3 (a) to 3 (d) are cross-sectional views schematically showing one step in the method for manufacturing the gas blowing plate of the plasma etching apparatus of the present invention.

[Explanation of symbols]

10 gas outlet 11 Porous silicon carbide layer 12 Dense silicon carbide layer 13 through holes 14 cavities 20 Plasma etching equipment 22 Upper electrode plate 23 Exhaust port 24 chambers 25 Lower electrode plate 26 Blowout plate support member 26a Supply pipe 110 green sheets 120 dense silicon carbide coating 130 T-shaped pin

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G046 MA14 MB01 MB08 MC02                 5F004 AA01 AA14 BA06 BA09 BB11                       BB18 BB28 BB29 CA06

Claims (10)

[Claims] 1. A gas blow-out plate of a plasma etching apparatus, which constitutes a part of an electrode plate and allows a reaction gas to flow therethrough, wherein the gas blow-out plate has a large number of open pores therein. A gas blowing plate for a plasma etching apparatus, comprising: a porous silicon carbide layer having: and a dense silicon carbide layer having a large number of through holes, which are laminated and integrated. 2. The porosity of the porous silicon carbide layer is 30 to 50.
%, The gas blowing plate of the plasma etching apparatus according to claim 1. 3. A portion of the porous silicon carbide layer that is in contact with the through hole formed in the dense silicon carbide layer has the same cross sectional area as the through hole or a larger cross sectional area than the through hole. The gas blowing plate of the plasma etching apparatus according to claim 1, wherein a cavity having a cross-sectional area is formed. 4. The gas blowing of the plasma etching apparatus according to claim 1, wherein the dense silicon carbide layer is a coating layer formed on the surface of the porous silicon carbide layer by a chemical vapor deposition method. Board. 5. An impregnated layer impregnated with silicon carbide is formed in the vicinity of the surface of the porous silicon carbide layer which is in contact with the dense silicon carbide layer, and the through-hole has the dense silicon carbide layer. A layer formed by penetrating a layer and the impregnated layer.
2. A gas blowing plate of the plasma etching apparatus according to any one of 1. 6. The gas blowing plate of the plasma etching apparatus according to claim 5, wherein the impregnated layer has a thickness of 10 to 30 μm. 7. The gas blowing plate of the plasma etching apparatus according to claim 1, wherein the reaction gas blowing port of the through hole formed in the dense silicon carbide layer is chamfered. 8. The dense silicon carbide layer made of Si, C, O, N,
The content of impurities other than Y is 5 ppm or less.
A gas blowing plate of the plasma etching apparatus according to any one of items 1 to 7. 9. The process brittle layer on the reaction gas blowing side of the dense silicon carbide layer has a thickness of 30 μm or less.
8. A gas blowing plate for a plasma etching apparatus according to any one of 8 above. 10. A method for manufacturing a gas blowing plate of a plasma etching apparatus, which constitutes a part of an electrode plate and allows a reaction gas to flow therethrough, wherein a flat plate is joined to one end of a rod-shaped body. A plurality of the flat plate portions of the V-shaped pins and / or one end portions of the rod-shaped pins are placed so as to be embedded in one main surface of the green sheet to be the porous silicon carbide layer, and then the green sheets are placed in an inert atmosphere. A firing step of firing to produce a porous silicon carbide layer, and at least a surface of the porous silicon carbide layer on which the T-shaped pins and / or the rod-shaped pins are formed is densely formed by a chemical vapor deposition method. Of a laminated body by forming a high-quality silicon carbide coating, and polishing the surface of the dense silicon carbide coating to expose a part of the T-shaped pin and / or the rod-shaped pin. Let A polishing step of producing a dense silicon carbide layer, and a decomposition and removal step of heating the polishing-treated laminated body in an oxidizing atmosphere to decompose and remove the T-shaped pin and / or the rod-shaped pin. A method of manufacturing a gas blowing plate of a plasma etching apparatus, comprising: