WO2011018912A1

WO2011018912A1 - Plasma cvd apparatus, plasma electrode, and method for manufacturing semiconductor film

Info

Publication number: WO2011018912A1
Application number: PCT/JP2010/057383
Authority: WO
Inventors: 正和滝; 睦津田; 賢治新谷; 謙今村
Original assignee: 三菱電機株式会社
Priority date: 2009-08-10
Filing date: 2010-04-26
Publication date: 2011-02-17
Also published as: DE112010003248T5; CN102473612B; JPWO2011018912A1; DE112010003248B4; JP5398837B2; CN102473612A

Abstract

The plasma electrode (30) of a plasma CVD apparatus (40) is configured by providing a main electrode section (21), which is provided with a process gas introducing port (second process gas introducing port (21a)); and a gas shower plate section (23), which is attached to an end portion of the main electrode section and forms a gas diffusion space (DS) between the main electrode section and the gas shower plate section. A plurality of gas jetting ports (23a) for jetting a process gas are formed in the gas shower plate section, and inside of the gas diffusion space, a gas diffusion plate (25), which has a plurality of gas distribution ports (25a) for distributing the process gas, and a plurality of heat transfer pillar sections (27) that pass through the gas distribution ports of the gas diffusion plate and thermally connect the gas shower plate section and the main electrode section to each other, are disposed. A space is formed between the inner wall of each of the gas distribution ports, and the circumferential surface of each of the heat transfer pillar sections that pass through the gas distribution ports.

Description

Plasma CVD apparatus, plasma electrode, and method for manufacturing semiconductor film

The present invention relates to a plasma CVD (Chemical Vapor Deposition) apparatus used for forming a thin film or the like, a plasma electrode, and a semiconductor film manufacturing method using the apparatus.

The plasma CVD apparatus is widely used as an apparatus for forming a thin film such as an amorphous silicon thin film or a microcrystalline silicon thin film on a substrate. Nowadays, for example, a plasma CVD apparatus capable of forming a thin film having a large area such as a silicon thin film used for a power generation layer of a thin film silicon solar cell at a high speed at a time has been developed.

For example, in Patent Document 1, a gas blowing face plate in which a plurality of gas blowing holes for blowing out a reactive gas and a plurality of plasma promoting holes for promoting the generation of plasma are formed in a plasma electrode (counter electrode). Thus, a plasma CVD apparatus that can form a thin film having a large area at high speed is described. In this plasma CVD apparatus, the plurality of plasma promotion holes are formed on the surface of the gas blowing face plate facing the substrate without penetrating the gas blowing face plate.

Also, a so-called “high pressure depletion method” is known as a method capable of forming a thin film having a large area at a higher speed than the film formation by the plasma CVD apparatus described in Patent Document 1. This high pressure depletion method is one of the plasma CVD methods, and a film forming chamber (vacuum container) is formed by a plasma CVD apparatus in which a distance between a stage portion on which a film forming substrate is placed and a plasma electrode is narrowed to about 10 mm. Film formation is performed by generating plasma in a high-frequency electric field while keeping the inside at high pressure and depleting (insufficient) the source gas.

When a large-area thin film is formed at a time by the plasma CVD method, a large plasma electrode is used regardless of the structure of the plasma CVD apparatus used and the film formation principle. Since the plasma electrode receives a heat input from the plasma at the time of film formation and rises in temperature, the larger the plasma electrode, the larger the amount of thermal deformation at the time of film formation. For example, when the temperature of a plasma electrode having a size of 1 m square when viewed in plan from the film formation substrate side is increased by 20 ° C. due to heat input from the plasma, the plasma electrode generally has 0 in the vertical and horizontal directions, respectively. .Expands about 4 mm. At this time, if the periphery of the plasma electrode is fixed, the plasma electrode swells up to about 10 mm toward the stage part, and the distance between the plasma electrode and the stage part greatly deviates from the set value, resulting in process characteristics during film formation. Adversely affected.

In order to suppress thermal deformation of the plasma electrode, it is desirable to dissipate the heat input from the plasma to the outside as much as possible. For example, as in the plasma electrode (shower head) of Patent Document 2, a gas diffusion space is formed by an upper plate in which process gas introduction holes are formed and a lower plate in which a plurality of gas passage holes are formed. If an intermediate plate with holes is provided in the gas diffusion space and a plurality of heat transfer members are provided between the intermediate plate and the upper plate and between the lower plate and the intermediate plate, the plasma is transferred from the plasma to the lower plate. Since the conducted heat is sequentially conducted to the heat transfer member, the intermediate plate, the heat transfer member, and the upper plate and is dissipated to the outside from the upper plate, it is easy to suppress thermal deformation of the plasma electrode.

JP 2002-237460 A JP 2009-10101 A

However, in the plasma electrode (shower head) specifically described in Patent Document 2, since each heat transfer member is arranged so as not to overlap with the gas passage hole of the intermediate plate, the uniformity of the generated plasma It is difficult to increase the diameter of the heat transfer member or increase the number of heat transfer members while maintaining the above. As a result, it is difficult to increase the thermal conductivity from the lower plate to the upper plate to improve the cooling performance of the plasma electrode.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a plasma CVD apparatus, a plasma electrode, and a method for manufacturing a semiconductor film, which facilitate the stable deposition of a large-area thin film at a high speed. To do.

The plasma CVD apparatus according to the present invention includes a film formation chamber, a stage portion for mounting a film formation substrate disposed in the film formation chamber, and a plasma electrode disposed in the film formation chamber so as to face the stage portion. The plasma electrode includes a main electrode portion provided with a process gas introduction hole and a plurality of gas discharge holes for discharging process gas to the stage portion side. A gas shower plate part that is attached to the stage part side and forms a gas diffusion space between the main electrode part, a plurality of gas flow holes for the process gas to circulate, and a gas shower plate part, A gas diffusion plate disposed in the gas diffusion space so as to oppose each other, and a plurality of transmission lines disposed in the gas diffusion space and thermally connecting the gas shower plate portion and the main electrode portion through the gas flow holes. With thermal pillar A, wherein the air gap is formed between the peripheral surface of the heat transfer pillar portion through an inner wall and the gas flow hole of the gas flow holes.

In the plasma CVD apparatus of the present invention, since the heat transfer pillar portion is passed through the gas flow hole formed in the gas diffusion plate, the diameter of the heat transfer pillar portion is increased or the heat transfer pillar portion is maintained while maintaining the uniformity of the generated plasma. It is easy to increase the number of As a result, it becomes easy to enhance the cooling performance of the plasma electrode and suppress its thermal deformation, and it becomes easy to form a large-area thin film stably at high speed.

FIG. 1 is a cross sectional view schematically showing Embodiment 1 of the plasma CVD apparatus of the present invention. FIG. 2 is an enlarged view of a part of the plasma electrode in FIG. FIG. 3 is a cross-sectional view schematically showing a plasma electrode (shower head) of Patent Document 2. As shown in FIG. FIG. 4 is a sectional view showing a part of a schematic configuration of Embodiment 3 of the plasma electrode according to the present invention. FIG. 5 is an enlarged cross-sectional view showing a part of the plasma electrode of FIG. 6 is an exploded cross-sectional view of the plasma electrode of FIG. FIG. 7 is a cross-sectional view showing a part of a schematic configuration of Embodiment 4 of the plasma electrode according to the present invention.

Hereinafter, embodiments of the plasma CVD apparatus of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following form.
Embodiment 1 FIG.

FIG. 1 is a sectional view schematically showing Embodiment 1 of the plasma CVD apparatus of the present invention, and FIG. 2 is an enlarged view of a part of the plasma electrode in FIG. A plasma CVD apparatus 40 shown in FIG. 1 is a horizontal apparatus including a film forming chamber 10, a stage unit 20 and a plasma electrode 30 disposed in the film forming chamber 10. The process gas discharged to the side is turned into plasma by a high-frequency electric field formed between the plasma electrode 30 and the stage unit 20, and a thin film is formed on the film formation substrate 50 such as a glass substrate placed on the stage unit 20. To do.

As shown in FIG. 1, the film forming chamber 10 includes a top plate portion 1 in which a first process gas introduction hole 1 a for introducing a process gas into the film forming chamber 10 is formed, and the top plate portion. 1 is a hollow body 5 disposed on the lower surface side of the body 1 via a high-frequency insulating member 3, a bottom plate 7 that closes the lower end side of the body 5, and the body 5 attached to the outer periphery of the body 5. 5 is a box-like body having a tubular exhaust pipe connecting portion 9 provided with an exhaust port 9a communicating with the five exhaust ports 5a. Although not shown, a shield member is disposed around the top plate portion 1 so that a high frequency applied to the top plate portion 1 does not leak to the outside. Further, the stage unit 20 is provided on the bottom plate unit 7, and at the time of film formation, the deposition target substrate 50 is placed on the stage unit 20 and the stage unit 20 is grounded.

The plasma electrode 30 includes a main electrode portion 21 provided with a second process gas introduction hole 21a, a gas shower plate portion 23 that forms a gas diffusion space DS between the main electrode portion 21, and a gas diffusion space DS. The gas diffusion plate 25 and the plurality of heat transfer pillar portions 27 are arranged on the top plate portion 1 side in the film forming chamber 10 with a predetermined interval from the upper surface of the stage portion 20. The distance between the plasma electrode 30 and the stage unit 20 is, for example, about several mm to several tens mm depending on the film forming conditions.

The main electrode portion 21 is a box-like body having an opening on the stage portion 20 side, and a second process gas introduction hole 21a is provided on the top side of the main electrode portion 21. The main electrode portion 21 is attached to the lower surface of the top plate portion 1 such that the second process gas introduction hole 21a communicates with the first process gas introduction hole 1a. Receive power supply. A flow path 21 b for cooling the main electrode portion 21 by flowing a coolant such as water is formed in the top portion of the main electrode portion 21.

As shown in FIGS. 1 and 2, the gas shower plate portion 23 is a flat plate member having a plurality of gas discharge holes 23a for discharging process gas to the stage portion 20 side. The arrangement is selected so that the process gas can be uniformly discharged from the plasma electrode 30 to the stage unit 20 side. The gas shower plate portion 23 is provided on the end portion of the main electrode portion 21 on the stage portion 20 side, specifically on the lower end of the side wall portion of the main electrode portion 21 and the lower end of each heat transfer pillar portion 27, for example, with screws or the like. It is attached by a fixture S ₁ (see FIG. 2). A space between the top surface inside the main electrode portion 21 and the upper surface of the gas shower plate portion 23 becomes a gas diffusion space DS.

The gas diffusion plate 25 is a plate-like member having a plurality of gas flow holes 25a through which process gas flows and a plurality of fixing pillar portions 25b, and is spaced from the gas shower plate portion 23, and The gas shower plate portion 23 is disposed in the gas diffusion space DS so as to face each other. The arrangement position of each gas circulation hole 25a is selected so as not to overlap the gas discharge hole 23a of the gas shower plate portion 23 in plan view. The gas diffusion plate 25 is fixed to the main electrode portion 21 by, for example, a fixing tool S ₂ (see FIG. 2) such as a screw inserted into the fixing pillar portion 25b from the gas shower plate portion 23 side.

By providing the gas diffusion plate 25 in the gas diffusion space DS, the process gas introduced into the gas diffusion space DS through the first process gas introduction hole 1a and the second process gas introduction hole 21a is transferred to the gas diffusion space DS. It becomes easy to diffuse uniformly inside. Further, by disposing each gas circulation hole 25a so as not to overlap the gas discharge hole 23a in plan view, it becomes easy to discharge the process gas from the plasma electrode 30 into the film forming chamber 10 uniformly. As a result, it is easy to improve the uniformity of plasma generated in the space between the plasma electrode 30 and the deposition target substrate 50 during film formation. A part of the flow direction of the process gas in the plasma electrode 30 is indicated by a dashed arrow A in FIG.

Each heat transfer pillar portion 27 protrudes from the top of the main electrode portion 21 toward the gas shower plate portion 23, and each heat transfer pillar portion 27 passes through the gas flow hole 25 a and is a gas shower plate. The gas shower plate part 23 and the main electrode part 21 are thermally connected. A gap is formed between the inner wall of the gas flow hole 25a and the peripheral surface of the heat transfer pillar portion 27 passing through the gas flow hole 25a so that the process gas can flow. In the illustrated example, the main electrode portion 21 and each heat transfer pillar portion 27 are integrally formed from one material.

Each of the main electrode part 21, the gas shower plate part 23, the gas diffusion plate 25, and the heat transfer pillar part 27 constituting the plasma electrode part 30 is generally made of aluminum. However, the thermal conductivity, electrical conductivity, In consideration of mechanical strength and the like, it is also possible to manufacture with other metal materials, alloy materials, composite metal materials and the like.

When the plasma CVD apparatus 40 having the above-described configuration is used, the top panel 1 is connected to the high-frequency power source 60 (see FIG. 1) via the power wiring 55 (see FIG. 1) and the high-frequency matching unit (impedance matching unit; not shown). The high frequency power supply 60 receives the supply of high frequency power. The high frequency power supplied to the top plate portion 1 is conducted from the top plate portion 1 to the plasma electrode 30, and from the plasma electrode 30 to the stage portion 20 and the deposition target substrate 50 placed on the stage portion 20. Conducted with. A high-frequency electric field is formed in the space between the plasma electrode 30, the stage unit 20, and the deposition target substrate 50. Further, when the plasma CVD apparatus 40 is used, a coolant such as water is caused to flow through the flow path 21 b in the main electrode portion 21.

When the plasma CVD apparatus 40 is used, a process gas supply source (not shown) and the first process gas introduction hole 1a are connected to each other via a process gas supply pipe (not shown) to the plasma electrode 30. While the gas is supplied, an exhaust pump (not shown) is connected to the exhaust pipe connection portion 9 via the exhaust pipe, and the inside of the film forming chamber 10 is adjusted to a desired pressure.

When a silicon thin film is formed on the deposition target substrate 50, for example, a mixed gas of monosilane (SiH ₄ ) gas as a silicon source and hydrogen (H ₂ ) gas as a carrier gas is used as a process gas. The process gas is introduced into the plasma electrode 30 from the first process gas introduction hole 1a through the second process gas introduction hole 21a, and then discharged from the gas discharge holes 23a of the gas shower plate part 23 to the stage part 20 side. Then, it is turned into plasma in the above-mentioned high-frequency electric field. By this plasma formation, active species such as SiH ₃ , SiH ₂ , SiH, Si, and H are generated, and these active species enter the deposition target substrate 50 to be amorphous or fine on the deposition target substrate 50. Crystalline silicon is deposited. As a result, an amorphous or microcrystalline silicon thin film is formed on the deposition target substrate 50.

While the film is being formed, the main electrode portion 21 of the plasma electrode 30 receives heat input from the plasma, but the main electrode portion 21 is cooled by the refrigerant flowing through the flow path 21b. Thermal deformation is suppressed. Further, the gas shower plate portion 23 also receives heat input from the plasma, but since the heat conducted from the plasma to the gas shower plate portion 23 is conducted from each heat transfer pillar portion 27 to the main electrode portion 21, the gas shower plate 23 The part 23 can also suppress thermal deformation. A part of the heat conduction direction in the plasma electrode 30 at the time of film formation is indicated by a dashed-dotted arrow B in FIG.

In the plasma CVD apparatus 40 in which thermal deformation of the plasma electrode 30 during film formation is suppressed as described above, the heat transfer pillar portion 27 is passed through the gas flow hole 25a formed in the gas diffusion plate 25. Compared with the case where the heat transfer pillars are provided so that they do not pass, the diameter of the heat transfer pillars 27 is increased while maintaining the uniformity of the generated plasma, or the number of heat transfer pillars 27 is increased. Is easy. This point will be specifically described with reference to FIG.

FIG. 3 is a cross-sectional view schematically showing the plasma electrode (shower head) of Patent Document 2. The plasma electrode 130 shown in the figure includes an upper plate 121 provided with a process gas introduction hole 121 a and a lower plate that is attached to an end of the upper plate 121 and forms a gas diffusion space DS between the upper plate 121. 123, an intermediate plate 125 disposed in the gas diffusion space DS, and a cover member 127 attached to the lower surface of the lower plate 123. In addition, a plurality of heat transfer members 129 a disposed between the intermediate plate 125 and the upper plate 121 and a plurality of heat transfer members 129 b disposed between the intermediate plate 125 and the lower plate 123 are also provided. The lower plate 123 is provided with a plurality of gas passage holes 123a through which process gas flows, and the intermediate plate 125 is provided with a plurality of gas passage holes 125a through which process gas flows. The cover member 127 is provided with a plurality of gas discharge holes 127a for discharging process gas.

In the plasma electrode 130 configured as described above, if the gas passage hole 125a of the intermediate plate 125 and the

heat transfer members

129a and 129b overlap, it becomes difficult to uniformly discharge the process gas, and the generated plasma is uniform. Sex is reduced. For this reason, each heat-

transfer member

129a, 129b is arrange | positioned so that it may not overlap with the gas passage hole 125a. For this reason, the design flexibility of the plasma electrode 130 is relatively low, and it is difficult to increase the diameter of the

heat transfer members

129a and 129b and increase the number of

heat transfer members

129a and 129b.

On the other hand, in the plasma electrode 30 of the plasma CVD apparatus 40 shown in FIG. 1, since the heat transfer pillar portion 27 is passed through the gas flow hole 25a as described above, the heat transfer pillar is maintained while maintaining the uniformity of the generated plasma. It is easy to increase the diameter of the portion 27 or increase the number of the heat transfer pillar portions 27.

As a result, in the plasma CVD apparatus 40, even when the plasma electrode 30 is enlarged to form a thin film with a large area at a time, the diameter of the heat transfer pillar portion 27 is increased or the heat transfer pillar portion 27 is increased. It is easy to improve the cooling performance of the plasma electrode 30 by increasing the number of the above and suppress thermal deformation during film formation. Therefore, it becomes easy to form a large-area thin film stably at high speed. For example, even if the plasma electrode 30 is enlarged so that the size in plan view is about 1.1 m × 1.4 m, the film forming surface having a film forming surface of about 1.1 m × 1.4 m is formed. It becomes easy to form a thin film such as a silicon thin film on the substrate stably at a high speed. It is also easy to improve the yield.
Embodiment 2. FIG.

In this embodiment, an example in which a microcrystalline silicon film is deposited over a glass substrate using a silane gas (SiH ₄ ) and a hydrogen gas (H ₂ ) with the apparatus illustrated in FIG. 1 will be described. The plasma electrode 30 of the plasma CVD apparatus used here has a size of 1.2 m × 1.5 m in plan view. Further, the heat transfer pillar portion 27 having a diameter of 15 mm was disposed in the gas diffusion space DS with a pitch of 40 mm.

A glass substrate 7 (thickness: 4 mm) of 1400 mm × 1100 mm was placed on the stage unit 20 in the film forming chamber 10 evacuated, and the substrate temperature was raised to 200 ° C. by a heater (not shown). Next, the stage part 20 was set so that the space | interval of the gas shower plate part 23 and a glass substrate might be set to 5 mm.

In this state, SiH ₄ gas and H ₂ gas were supplied to the first process gas introduction hole 1a at flow rates of 1 slm and 50 slm, respectively. The supplied process gas is introduced into the gas diffusion space DS, and is supplied into the film forming chamber 10 from the gas discharge hole 23a of the gas shower plate portion 23 through the gas circulation hole 25a.

Next, the gas was exhausted from the exhaust port 5a by an exhaust pump (not shown) so that the gas pressure in the film forming chamber 10 was 1000 Pa. After the gas pressure was stabilized, high frequency power of 13.56 MHz was supplied to generate SiH ₄ / H ₂ mixed plasma between the plasma electrode 30 and the glass substrate. The high frequency power was supplied at 12 kW (power density = about 0.67 W / cm ² ) and film formation was performed for 50 minutes.

When film formation was performed under these conditions, a silicon thin film was deposited with a film thickness of 2 μm and an in-plane uniformity of film thickness of ± 8%, and uniform film formation with a practical large-area substrate size became possible. Also, the average value of the intensity ratio I _c / I _a of the crystalline silicon peak I _c at 520 cm ⁻¹ to the amorphous silicon peak I _{a at} 480 cm ⁻¹ measured by Raman spectroscopy is 7.4, and in-plane The uniformity was ± 10%, and a good microcrystalline silicon thin film could be obtained uniformly.

Here, the temperature rise of the gas shower plate 23 in a state where film formation was performed was measured using an optical fiber thermometer from the back side of the gas shower plate 23, that is, from the gas diffusion space DS side. As a result, when the temperature of the refrigerant flowing through the refrigerant flow path 21b was set to 20 degrees, the shower plate back surface temperature rose to 33 degrees and reached equilibrium. The rising temperature during film formation is 13 degrees, and it can be seen that the method of this embodiment can be sufficiently cooled by optimizing the diameter and number of the heat transfer pillar portions 27 necessary for cooling the gas shower plate 23. .

Further, the film thickness and film quality uniformity of the microcrystalline silicon thin film described above can be obtained because of the optimal arrangement of the gas discharge holes 23a necessary for ensuring the uniformity by the method of the present embodiment and the gas shower plate 23. This is because the configuration of the heat transfer pillar portion 27 necessary for cooling can be easily optimized at the same time.

Since the plasma CVD apparatus as described above is used for manufacturing a semiconductor film such as silicon, the in-plane uniformity of the film is good when the film is formed under a narrow condition where the distance between the gas shower plate portion 23 and the glass substrate is 10 mm or less. It becomes. In addition, even under conditions where high power is applied so that the average density of the high frequency power is 0.5 W / square cm or more on the surface of the gas shower plate portion 23, the deformation of the gas shower plate portion 23 is small and the in-plane of the film Uniformity is improved. As a result, a semiconductor film having excellent uniformity can be formed on a large substrate having an area of 1 square m or more, for example, 1 m or more on one side, and productivity is excellent.
Embodiment 3 FIG.

4 is a cross-sectional view showing a part of a schematic configuration of a plasma electrode according to Embodiment 3 of the present invention, FIG. 5 is an enlarged cross-sectional view showing a part of the plasma electrode of FIG. 4, and FIG. It is sectional drawing which decomposes | disassembles and shows the plasma electrode of FIG. 4 to 6, in the third embodiment, the fixture S ₁ ′ for fixing the heat transfer pillar portion 27 and the gas shower plate portion 23 sinks more than the shower plate surface (surface on the plasma generation side). And the lid (cover) F ₁ is attached on the surface so that the shower plate surface is substantially flat.

In order to facilitate replacement, the gas shower plate portion 23 is attached to the heat transfer pillar portion 27 by a fixture S ₁ ′ (screw or bolt) that can be tightened or loosened from the stage portion 20 side (plasma surface side).

A through hole 71 with counterbore 70 is provided in the gas shower plate portion 23 so that the fixture S ₁ ′ does not protrude from the surface of the gas shower plate portion 23, and the fixing device S ₁ is a screw with a head from the plasma surface side. 'Is inserted and inserted into the screw hole 72 of the heat transfer pillar portion 27 on the back surface side, and the screw is tightened. In order to obtain good heat conduction, each heat transfer pillar portion 27 is sufficiently fastened with a screw so that each heat transfer pillar portion 27 and the gas shower plate portion 23 are brought into close contact with each other.

In the first embodiment, the gas shower plate portion 23 is attached to the heat transfer pillar portion 27 with screws. In the first embodiment, as shown in FIG. 2, the head of the screw is combined with a fixture S ₁ having a flat countersunk screw with a flat head tip and a countersunk hole. The gas shower plate portion 23 is made substantially flat so that it substantially coincides with the plasma surface side of the gas shower plate portion 23.

However, the screw has + and-depressions that can be rotated and installed with a screwdriver. Since the screw for fixing the gas shower plate portion 23 of the CVD apparatus for forming a meter-sized substrate to the heat transfer pillar portion 27 is about M5, generally the depth of the above-mentioned hollow portion is usually ~ The following problems occur due to 2 mm.

To fasten with sufficient force, a large plus, hexagonal hole, or minus groove is needed to engage the screw head with the tip of the fastening tool, and the depth of this recess should be reduced. Is difficult.

As described above, in the high pressure depletion method process, the interval between the stage unit 20 on which the deposition target substrate is placed and the plasma electrode 30 is set to be as narrow as about 10 mm. As a result, the amount of the recess of the screw with respect to the set gap between the gas shower plate portion 23 and the stage portion 20 is several tens of percent, so that the plasma electrode surface in contact with the plasma is not flat and uneven. Therefore, the substantial distance from the stage unit 20 to the plasma electrode 30 varies within the surface of the gas shower plate unit 23. This unevenness affects plasma generation, and for example, the plasma density increases and decreases where there are screws and where there are no screws.

In order to solve this problem, as shown in FIGS. 4 to 6, a fixture S ₁ ′ for fixing the gas shower plate portion 23 to the heat transfer pillar portion 27 is attached by being submerged from the shower plate surface. A counterbore 70 is provided on the gas shower plate portion 23 in order to sink and attach the fixture S ₁ ′, which is a screw. After the fixing tool S ₁ ′, which is a screw, is attached, the lid F ₁ is attached to the counterbore 70. In this case, the depth of the counterbore 70 is the same as the thickness of the lid F ₁ so that no unevenness occurs on the shower plate surface. The lid F ₁ is attached with a screw provided on the gas shower plate portion 23. The lid F ₁ is not particularly required to be attached and fixed, but if the lid F ₁ is provided with a slight recess 73 of 1 mm or less, the lid F ₁ can be securely screwed into the gas shower plate portion 23.

This lid F ₁ is different from the fixture S ₁ 'for fastening the gas shower plate 23 and the heat transfer pillar portion 27, there is no need to fasten by a strong force, the screw holes to be used for detaching the lid F ₁ The grooves and the grooves can be made very small like a slight depression 73. The recess 73 may not be provided as long as it can be detached and attached by being rotated by the frictional force of the surface. The material of the lid F ₁ is not particularly defined, but the same material as the gas shower plate portion 23 is desirable.

With the above configuration, the gas shower plate portion 23 and the heat transfer pillar portion 27 can be fastened with a sufficient force, and the surface of the gas shower plate portion 23 in contact with the plasma has a flat surface without unevenness, so that the plasma is uniform. Improves.

As shown in FIG. 2, when the head of the fixture S ₁ is exposed to the plasma surface, it is desirable that the material of the fixture S ₁ is the same as that of the gas shower plate portion 23. Since the head of the fixture S ₁ ′ is completely hidden, there is no problem even if a material different from the gas shower plate portion 23 is used.

For example, when the gas shower plate 23 is made of aluminum or an alloy thereof, it is possible to use screws of stainless steel or copper alloy that are harder than those. In this case, it is further preferable to insert an insert screw made of, for example, stainless steel or copper alloy, for example, a helical insert, into the screw hole 72 on the heat transfer pillar portion 27 side. Even if strong fastening is repeated with a hard screw or screw hole, damage to the screw is reduced.

Further, in order to facilitate the tightening and loosening of the screw, a film of a solid lubricant or the like (for example, molybdenum disulfide) may be formed in the screw groove. The replacement operation of the gas shower plate portion 23 is facilitated and the lid F ₁ is provided, so that these solid lubricants can be prevented from entering the film forming chamber 10 from the screw groove and being contaminated.
Embodiment 4 FIG.

In the above-described embodiment, the method of attaching the gas shower plate portion 23 to the heat transfer pillar portion 27 with a screw has been described, but it may be attached with a nut. FIG. 7 is a cross-sectional view showing a part of a schematic configuration of Embodiment 4 of the plasma electrode according to the present invention. In FIG. 7, the heat transfer pillar portion 27 is provided with a screw 81 at the end on the side where the gas shower plate portion 23 is attached. The gas shower plate 23 is attached and fixed by tightening a nut 82 to the screw 81. When the nut 82 is attached, the lid F ₂ is attached in the same manner as described above. In this case, the surface of the stage side of the gas shower plate 23, a counterbore 83 which cover F ₂ enters the nut 82 is provided, flush with the surface of the lid F ₂ gas shower plate 23 surface depth of counterbore 83 To prevent unevenness.

As described above, the plasma CVD apparatus of the present invention has been described with reference to the embodiment. However, as described above, the present invention is not limited to the above embodiment. For example, whether or not the heat transfer pillar portion is integrally formed with the main electrode portion from one material can be appropriately selected. After preparing the main electrode part without the heat transfer pillar part or the top part of the main electrode part and the heat transfer pillar part separately, for example, the individual heat transfer pillar parts are attached to the main electrode part by a fixture such as a screw. It may be attached to the top.

However, from the viewpoint of obtaining a plasma electrode with high cooling performance, it is preferable to integrally form each heat transfer pillar portion and the main electrode portion from one material. If each heat transfer pillar part is formed integrally with the main electrode part from one material, there is no contact interface between the heat transfer pillar part and the main electrode part, so there is no decrease in heat conduction at the contact interface and cooling performance. It becomes easy to obtain a high plasma electrode. The number of heat transfer pillar portions and the number of gas flow holes in the gas diffusion plate may be the same, or the number of gas flow holes may be larger than the number of heat transfer pillar portions.

The shape of each of the main electrode portion and the gas shower plate portion constituting the plasma electrode may be any shape as long as a gas diffusion space can be formed between the main electrode portion and the gas shower plate portion. In addition to a box-like body and the other plate-like, both can be box-like bodies. Further, the top of the main electrode portion can also function as the top plate of the film forming chamber. That is, it is possible to configure a plasma CVD apparatus using the top of the main electrode portion as the top plate of the film forming chamber.

The plasma CVD apparatus of the present invention may be either a horizontal type or a vertical type, and either type can be appropriately selected according to the use of the plasma CVD apparatus. The present invention can be variously modified, modified, combined, etc. other than those described above.

The plasma CVD apparatus according to the present invention is suitable as an apparatus for forming a thin film such as a silicon thin film, particularly as an apparatus for forming a thin film having a large area at a high speed at a time.

DESCRIPTION OF SYMBOLS 1 Top plate part 1a 1st process gas introduction hole 3 High frequency insulation member 5 Trunk part 5a Exhaust port 7 Bottom plate part 9 Exhaust pipe connection part DS Gas diffusion space 10 Deposition chamber 20 Stage part 21 Main electrode part 21a 2nd process gas introduction Hole 21b Refrigerant flow path 23 Gas shower plate part 23a Gas discharge hole 25 Gas diffusion plate 25a Gas flow hole 27 Heat transfer pillar part 30 Plasma electrode 40 Plasma CVD apparatus 50 Film-forming substrate 60 High frequency power supply S ₁ , S ₁ ′, S ₂ fixture F ₁ , F ₂ lid 70, 83

counterbore

71, 84 through hole 72 screw hole 73 recess 81 screw 82 nut

Claims

A plasma comprising a film formation chamber, a stage portion for placing a film formation substrate disposed in the film formation chamber, and a plasma electrode disposed in the film formation chamber so as to face the stage portion A CVD apparatus,
The plasma electrode is
A main electrode portion provided with a process gas introduction hole;
A gas that has a plurality of gas discharge holes for discharging process gas to the stage portion side, is attached to the stage portion side of the main electrode portion, and forms a gas diffusion space between the main electrode portion The shower plate,
A gas diffusion plate having a plurality of gas flow holes for flowing the process gas, and disposed in the gas diffusion space so as to face the gas shower plate portion;
A plurality of heat transfer pillar portions disposed in the gas diffusion space and thermally connecting the gas shower plate portion and the main electrode portion through gas flow holes;
And a gap is formed between the inner wall of the gas flow hole and the peripheral surface of the heat transfer pillar portion passing through the gas flow hole.
The plasma CVD apparatus according to claim 1, wherein the main electrode portion and the heat transfer pillar portion are integrally formed from one material.
3. The plasma CVD apparatus according to claim 1, wherein a flow path for cooling the main electrode portion by flowing a coolant is formed inside the main electrode portion.
The heat transfer pillar and the shower plate are fixed with screws, the screws are attached by sinking in a counterbore provided on a stage side surface of the shower plate, and a cover is provided on the counterbore. The plasma CVD apparatus according to any one of the above.
A main electrode portion provided with a process gas introduction hole;
A plurality of gas discharges arranged to face the main electrode part so as to form a gas diffusion space between the main electrode part and discharge process gas flowing into the gas diffusion space through the process gas introduction hole A gas shower plate with holes,
A gas diffusion plate disposed in the gas diffusion space so as to face the gas shower plate portion, and provided with a plurality of gas flow holes for flowing the process gas;
The gas shower plate portion and the main electrode portion are thermally connected through the gas flow holes, and a plurality of heat transfer pillar portions having gaps between the gas flow holes are provided. Plasma electrode.
6. The plasma electrode according to claim 5, wherein the gas flow hole and the gap are arranged so as not to overlap each other in plan view.
A method of manufacturing a semiconductor film using the plasma CVD apparatus according to any one of claims 1 to 4,
A method of manufacturing a semiconductor film, comprising: placing a substrate on the stage portion so that a distance between the gas shower plate portion and the substrate is 10 mm or less; and depositing a silicon thin film on the substrate.