JP5028044B2 - Manufacturing method of semiconductor thin film - Google Patents

Description

The present invention relates to the production how the semiconductor thin film, and more particularly relates to the production how the semiconductor thin film using the preferred plasma CVD method used for forming a uniform semiconductor thin film on a substrate surface having a large area .

  Thin film deposition by plasma CVD method for the formation of various semiconductor thin films on TFT (thin film transistor) arrays, thin film solar cells, photosensitive layers on photocopier drums, etc. formed on transparent substrates of liquid crystal display panels Technology is being used. In recent years, a liquid crystal display panel has been desired to have a large screen, and a thin film solar cell is also required to have a large area in order to improve a large power generation capacity and production efficiency. Therefore, a plasma CVD method and a plasma CVD apparatus capable of forming a large-area semiconductor thin film are required.

  FIG. 15 is a longitudinal sectional view schematically showing the configuration of a conventional plasma CVD apparatus. A plasma CVD apparatus (semiconductor thin film manufacturing apparatus) 61 shown in FIG. 15 is a vertical plasma CVD apparatus that can be used for manufacturing a semiconductor thin film having a large area. A temperature control panel (heater) 66 is provided. In use, a support member 68 on which a substrate (substrate) 80 on which a semiconductor thin film is to be formed is inserted from above the vacuum chamber 62, and the support member 68 is placed at a position where the electrode 65 and the substrate 80 face each other. Deploy.

  The vacuum chamber 62 is a rectangular parallelepiped box made of stainless steel, aluminum alloy, or the like. The vacuum chamber 62 is connected to an unillustrated exhaust vacuum pump, piping, a pressure control valve, and the like, and the inside of the vacuum chamber 62 can be depressurized to a predetermined pressure. On the other hand, the electrode 65 functions as a cathode electrode and is connected to a high-frequency power supply device (not shown). A gas supply device and piping (not shown) for supplying a source gas for forming a semiconductor thin film are connected to the electrode 65, and the source gas is supplied from a gas outflow hole formed in the electrode surface of the electrode 65. Is discharged.

FIG. 16 is an enlarged cross-sectional view of the main parts of the substrate 80 and the support member 68. The support member 68 has a rectangular frame shape having an opening 76 in the center, and a step 78 is formed at the end of the opening 76. When the substrate 80 is mounted, the peripheral portion of one surface (film formation surface) of the substrate 80 is engaged with the stepped portion 78, and the back plate 81 is disposed on the other surface (back surface) of the substrate 80. . The back plate 81 is detachably fixed to the support member 68 by a clamp 79 provided at the periphery of the back surface mounting surface opening 92 of the support member 68. Accordingly, the substrate 80 is positioned with respect to the support member 68 and is held and fixed in a state where a part of the substrate 80 is exposed from the opening 76 of the support member 68. The exposed surface 82 of the substrate 80 is surrounded by the planar portion 85 of the support member 68. The planar portion 85 forms a discharge surface together with the exposed surface 82 of the substrate 80. In general, the planar portion 85 is flat and has one plane.
In the state where the substrate 80 is mounted on the support member 68 as described above, the substrate 80 and the support member 68 are integrated to form the substrate support electrode 91 and are disposed so as to face the electrode 65.

  As shown in FIG. 17, the substrate 80 and the back plate 81 can be held and fixed without providing the support member 68 with the stepped portion 78. 17 is disposed so as to cover the opening 76 of the support member 68 from the back surface, and further, a back plate 81 is disposed from the back surface of the substrate 80, and a plurality of portions provided in the peripheral portion of the back mounting surface opening 92 are provided. The clip 77 is fixed to the support member 68.

  The support member 68 is made of, for example, stainless steel such as SUS304 or SUS430, an aluminum alloy, or the like, or a material having heat resistance and rigidity that is separately coated on the surface of the aluminum alloy in some cases. On the other hand, the back plate 81 is formed of carbon having excellent heat resistance and heat conduction. Further, the substrate 80 is adjusted to a constant temperature via the back plate 81 by the temperature control panel 66 in the vacuum chamber 62.

  The procedure for forming a thin film on the exposed surface 82 of the substrate 80 is as follows. First, as shown in FIG. 15, the substrate support electrode 91 (the support member 68 to which the substrate 80 is mounted) is disposed at a position where the exposed surface 82 of the substrate 80 faces the electrode 65. At this time, a plasma generation space is formed between the electrode 65 and the substrate support electrode 91. Next, the source gas is supplied from the gas outflow hole (not shown) on the surface of the electrode 65 to the plasma generation space, and the source gas is exhausted so that the inside of the vacuum chamber 62 has a certain pressure. Next, high-frequency power is applied to the electrode 65 to generate plasma between the electrode 65 and the substrate support electrode 91 (plasma generation space), and a semiconductor thin film is formed on the exposed surface 82 of the substrate 80.

  In the plasma CVD apparatus shown in FIG. 15, the exposed surface 82 of the substrate 80 is installed facing outward, but the exposed surface 82 as shown in FIG. There is also a plasma CVD apparatus. In the case of this plasma CVD apparatus, the support member 68 on which the substrate 80 is mounted is usually inserted horizontally from the front rather than from the upper part of the vacuum chamber 62.

  Generally, in a plasma CVD method and a plasma CVD apparatus, the uniformity of plasma generated in a film formation region (a part of a plasma generation space and covering an exposed surface of a substrate) is a semiconductor film formed on a substrate. It has a great influence on the uniformity and uniformity of the film thickness. Therefore, a device for making the plasma in the film formation region more uniform has been devised. For example, in the invention described in Patent Document 1, in the horizontal CVD apparatus, when the frequency of the high-frequency power supplied to the cathode electrode is in the VHF band, the plasma electric field at the peripheral portion in the large area parallel plate type film forming apparatus. In order to reduce the strength, the distance between the peripheral electrodes of the cathode electrode facing the substrate support electrode (anode electrode) is locally narrowed in the peripheral portion, thereby increasing the plasma electric field strength in the peripheral portion and The plasma is made uniform.

  On the other hand, it is the distance between the electrodes that largely controls the uniformity of the plasma. Particularly, when forming a film on a large-area substrate, the parallelism between the enlarged electrodes becomes important. Furthermore, in order to improve the deposition rate for the purpose of improving productivity, the input power of the high frequency power input to the electrode is increased, the frequency of the input power is increased (high frequency), or the inside of the chamber For example, the pressure is increased to reduce the distance between the substrate support electrode and the cathode electrode. However, in these cases, a higher degree of parallelism between the electrodes is required.

In the invention described in Patent Document 2, in a parallel plate high-frequency plasma CVD apparatus having a large area, a reference plane for measuring the parallelism between the film formation surface of the substrate and the cathode electrode surface is set, and the substrate electrode (film formation) is determined. The distance between the surface) and the cathode electrode is a predetermined value of 12 mm or less, the parallelism of the substrate electrode and the cathode electrode is adjusted to within 1 mm, and the variation in the film thickness distribution of the semiconductor thin film formed on the substrate is within the predetermined range. It is housed in.
JP-A-9-31268 JP 2002-270527 A

  As described above, in order to increase the area and improve the deposition rate, a large area cathode electrode and substrate are used, the distance between the electrodes is made as small as possible, high power and high frequency power is input, and the semiconductor thin film A film is being formed. At that time, the problem is the stabilization and homogenization of plasma in the film formation region. That is, if the plasma on the substrate is non-uniform during film formation, the film thickness and film quality distribution of the semiconductor thin film on the substrate become non-uniform, and the local variation greatly reduces the performance of the entire semiconductor thin film. Cause. As the substrate area increases, it becomes more difficult to maintain the uniformity of the plasma as the power of the high-frequency power is increased or the frequency is increased to improve the deposition rate. At that time, what is important is the flatness of the electrode surface of the cathode electrode, the flatness of the substrate support electrode, and the parallelism between these electrodes.

  However, when a semiconductor thin film is formed on a large area substrate of about 1 m □ or more, the size of the cathode electrode and the substrate support electrode both exceeds 1 m □, and maintaining these flatnesses, It is difficult to maintain the parallelism between the cathode electrode and the substrate support electrode due to machining accuracy, assembly accuracy, or deformation during vacuum or heating. Further, even if the electrode flatness of the same 1 mm is deteriorated or the parallelism between the electrodes is deteriorated, when the distance between the electrodes is reduced from 20 mm to 10 mm, the variation ratio is 5% to 10%. , The effect will be greater. As a result, when the distance between the electrodes is smaller, the variation in film thickness and film quality of the formed semiconductor thin film becomes large, and the performance of the entire semiconductor thin film is remarkably lowered.

  In the conventional plasma CVD apparatus shown in FIG. 15, the flatness of the electrode 65, the flatness of the substrate support electrode 91, and the parallelism between the electrode 65 and the substrate support electrode 91 (between the electrodes) are ideally maintained. In the case where it is leaned, as shown in FIG. 19A, the plasma 95 is well confined in the film formation region in the plasma generation space, and a uniform semiconductor thin film is formed up to the periphery of the substrate. However, when the parallelism between the electrodes is not maintained, the uniformity of the plasma in the film formation region decreases, and the uniformity and homogeneity of the semiconductor thin film formed on the film formation surface of the substrate decreases.

  For example, the behavior may be reversed depending on the pressure region and the magnitude of the high-frequency power, but when the interelectrode distance is small, the plasma 95 to be confined in the film formation region is near the planar portion 85 of the support member 68. Will spread. The degree of spread of the plasma 95 depends on the distance between the electrodes. If the degree is small, the state shown in FIG. 19B is obtained, and if the degree is large, the state shown in FIG. 19C is obtained. In the case of FIG. 19B in which the plasma spread is small, the uniformity degradation of the plasma 95 in the film formation region may fall within an allowable range, but when the plasma 95 spread is large as shown in FIG. The entire plasma energy is consumed by the plasma 95 in the planar portion 85 of the support member 68, and as a result, the plasma intensity on the exposed surface 82 of the substrate 80 becomes weak, and the semiconductor film is formed on the exposed surface 82. The film quality of the thin film may change.

  Similarly, the behavior may be reversed depending on the pressure region and the magnitude of the high frequency power, but when the distance between the electrodes increases, the generated plasma 95 contracts as shown in FIG. The plasma 95 cannot be spread on the exposed surface 82 of the 80, and the film thickness of the semiconductor thin film becomes thin at the periphery of the exposed surface 82, and the film quality changes.

  As described in Patent Document 2, the parallelism between the electrodes is improved to some extent by precisely adjusting the distance between the electrodes. However, it is difficult to stably ensure the flatness of the substrate support electrode and the cathode electrode due to the manufacturing accuracy and assembly accuracy, as well as deformation due to vacuum or heat.

  Further, as described in Patent Document 1, in the horizontal CVD apparatus, the problem that the electric field strength decreases at the outer edge of the electrode and the film thickness of the semiconductor thin film becomes thin is gradually increased from the cathode electrode to the outer edge. As a taper shape, the distance between the electrodes is reduced to improve the electric field distribution at the outer edge. However, when the parallelism between the electrodes is not good, the electric field strength at the outer edge becomes too strong, the plasma becomes non-uniform, and there is a concern about adverse effects on the semiconductor thin film. Further, when the cathode electrode is tapered, the cathode electrode is easily soiled, and maintenance performance is extremely lowered. Furthermore, when the vicinity of the gas outflow hole provided on the electrode surface of the cathode electrode is tapered, the length of the gas outflow hole changes, and the difference in pressure loss of each gas outflow hole causes a difference in gas supply amount. Inhomogeneity may occur, and the uniformity of the film thickness and film quality of the semiconductor thin film may be impaired.

An object of the present invention, the plasma can be stabilized, equalized, to provide a preparation how the semiconductor thin film using a plasma CVD method capable of depositing a uniform semiconductor thin film in a large area.

An invention according to claim 1 for solving the above-described problem is provided with an electrode, wherein a substrate on which a semiconductor thin film is to be formed is mounted on a support member, and a part or all of the substrate is exposed from the support member. The support member is disposed in the film forming chamber so that the substrate exposed surface faces the electrode surface, a plasma generation space is formed between the support member on which the substrate is mounted and the electrode, and high-frequency power is applied to the electrode. A method of manufacturing a semiconductor thin film including a plasma CVD process for forming a semiconductor thin film on an exposed surface of a substrate by supplying a discharge to form a semiconductor thin film, wherein a wall for shielding plasma is provided in the plasma generation space, and the support The member has a planar portion located on the outer edge of the substrate exposed surface and opposed to the electrode surface, the wall is provided on the planar portion, and the planar portion and the substrate exposed surface form a stepped portion. The distance between the electrode surface and the planar portion Is smaller than the distance between the electrode surface and the substrate exposed surface, and the height of the stepped portion is 0.5 mm or more and 4.0 mm or less, and the stepped portion has a height from the planar portion toward the substrate exposed surface. There is a method for manufacturing a semiconductor thin film characterized by being formed in a taper shape in which is reduced .

  The method for producing a semiconductor thin film of the present invention forms a semiconductor thin film by a plasma CVD process. That is, the method for producing a semiconductor thin film according to the present invention forms a thin film on a substrate mounted on a support member, and shields plasma in a plasma generation space between the support member mounted on the substrate and the electrode. Establish walls. In the method for producing a semiconductor thin film according to the present invention, since a wall for shielding plasma is provided in the plasma generation space, the plasma generated in the region (film formation region) covering the substrate exposed surface is directed from the film formation region to the outside of the plasma generation space. Even if it tries to spread, it collides with the wall and the plasma is confined in the film formation region. Therefore, the plasma is made more uniform in the film formation region. As a result, the film thickness of the semiconductor thin film formed on the substrate exposed surface is made more uniform, and the film quality becomes more uniform.

  Further, in the plasma CVD method of the present invention, since the structure in which the plasma is confined in the film formation region by the wall is adopted, other factors such as the flatness of the electrode surface of the electrode, the flatness of the substrate supporting electrode, and the parallelism between the electrodes Can be absorbed, and the plasma in the film formation region can be made uniform in a stable manner.

  Further, the method for producing a semiconductor thin film according to the present invention is characterized by the shape of the supporting member used. That is, in the manufacturing method of the semiconductor thin film using the conventional plasma CVD method, the planar portion of the supporting member to be used is flat and has one plane. However, in the manufacturing method of the semiconductor thin film of the present invention, the planar portion of the supporting member to be used is used. A wall for shielding plasma is provided. In the method for producing a semiconductor thin film according to the present invention, the support member for the substrate is provided with a wall on the planar portion, so that the plasma generated in the film forming region is exposed from the substrate exposed surface to the outside of the planar portion of the support member. Even if it is going to spread, it collides with a wall provided in the planar portion, and the plasma is confined in the film formation region. Therefore, the plasma is made more uniform in the film formation region. As a result, the film thickness of the semiconductor thin film formed on the substrate exposed surface is made more uniform, and the film quality becomes more uniform.

In the method for producing a semiconductor thin film of the present invention, the planar portion and the substrate exposed surface form a stepped portion, and the distance between the electrode surface and the planar portion is greater than the distance between the electrode surface and the substrate exposed surface. And the height of the step is 0.5 mm or more and 4.0 mm or less. With this configuration, plasma fluctuation from the substrate exposed surface to the planar portion of the support member is reduced, and the plasma is made more uniform.

In the method for producing a semiconductor thin film of the present invention, the stepped portion is formed in a tapered shape whose height decreases from the planar portion toward the substrate exposed surface. With this configuration, plasma fluctuation from the substrate exposed surface to the substrate-side electrode facing surface becomes extremely small, and the plasma is made more uniform.

According to a second aspect of the present invention, a substrate on which a semiconductor thin film is to be formed is mounted on a support member, and a part or all of the substrate is exposed from the support member. The support member is disposed so as to face the electrode surface, a plasma generation space is formed between the support member on which the base is mounted and the electrode, high frequency power is supplied to the electrode to generate discharge, A method of manufacturing a semiconductor thin film including a plasma CVD process for forming a semiconductor thin film on a substrate exposed surface, wherein a wall for shielding plasma is provided in the plasma generation space, and the support member is an outer edge of the substrate exposed surface. A planar portion facing the electrode surface, wherein the wall is provided on the planar portion, and the planar portion includes a substrate-side electrode facing surface adjacent to a substrate exposed surface, and the substrate-side electrode. Adjacent to the opposite side of the opposite side of the substrate exposed surface And the base-side electrode-facing surface and the end-side electrode-facing surface have a distance between the base-side electrode-facing surface and the electrode surface. The wall is formed by the step, and the base-side electrode facing surface and the base-exposed surface form a step, and the electrode surface and the base The distance from the side electrode facing surface is smaller than the distance between the electrode surface and the substrate exposed surface, and the height of the stepped portion is 0.5 mm or more and 4.0 mm or less. from a process for manufacturing semi-conductive thin film you characterized in that it is formed in a tapered shape in which the height becomes smaller toward the substrate exposed surface.

  In the method for producing a semiconductor thin film of the present invention, a step is provided in the planar portion of the supporting member to be used, and the step functions as a wall that shields plasma. That is, in the step, the distance between the end-side electrode facing surface and the electrode surface is smaller than the distance between the base-side electrode facing surface and the electrode surface. In other words, the step is convex toward the electrode, and the end-side electrode facing surface protrudes toward the electrode side with respect to the base-side electrode facing surface. In the method for producing a semiconductor thin film of the present invention, the wall that shields the plasma is formed by the step, so that the plasma generated in the film formation region tends to spread from the substrate exposed surface toward the planar portion of the support member. However, the plasma hits the step (wall) provided in the planar portion and is confined in the film formation region. Therefore, the plasma is made more uniform in the film formation region. As a result, the film thickness of the semiconductor thin film formed on the substrate exposed surface is made more uniform, and the film quality becomes more uniform.

In the method for producing a semiconductor thin film of the present invention, the base-side electrode facing surface and the base-exposed surface form a step, and the distance between the electrode surface and the base-side electrode facing surface is the electrode surface and the base-exposed surface. And the height of the stepped portion is 0.5 mm or more and 4.0 mm or less. With this configuration, the variation in plasma from the substrate exposed surface to the substrate-side electrode facing surface of the support member is reduced, and the plasma is made more uniform.

In the method for producing a semiconductor thin film of the present invention, the stepped portion is formed in a tapered shape whose height decreases from the substrate-side electrode facing surface toward the substrate exposed surface. With this configuration, plasma fluctuation from the substrate exposed surface to the substrate-side electrode facing surface becomes extremely small, and the plasma is made more uniform.

According to a third aspect of the invention, the height of the step is set forth in claim 2, wherein the electrode surface and the at most 1/20 or more and 1/3 of the distance between the substrate exposed surface It is a manufacturing method of a semiconductor thin film.

  In the method for producing a semiconductor thin film of the present invention, the height of the step is limited to a predetermined range. With this configuration, the plasma generated in the film formation region is reliably confined while maintaining the distance between the end-side electrode facing surface and the electrode surface to an extent that does not adversely affect the generation of plasma.

Said support member is made of a frame body having an opening, configured to expose a portion or all of the base from the opening is recommended (claim 4). In addition, a configuration in which the base is a plate and the base exposed surface is a part or all of one surface of the plate is also recommended (Claim 5 ).

The support member side by side a plurality of substrates mounted, some or all of each of the substrate is exposed from the support member, configured to be deposited may be employed a semiconductor thin film on a plurality of substrates (claim 6).

A related invention is a semiconductor thin film manufacturing apparatus for performing the above-described method for manufacturing a semiconductor thin film, the film forming chamber having an electrode, and the support member on which a base is held is located with respect to the film forming chamber The semiconductor thin film manufacturing apparatus is characterized in that the support member is disposed to face the electrode in the deposition chamber.

The present invention relates to a semiconductor thin film manufacturing apparatus. This semiconductor thin film manufacturing apparatus is for carrying out the semiconductor thin film manufacturing method of the present invention, has a film forming chamber equipped with electrodes, and a support member holding a substrate can be taken in and out of the film forming chamber. And the support member is arranged to face the electrode in the film forming chamber. According to this semiconductor thin film manufacturing apparatus, the plasma generated in the film forming region is made more uniform. As a result, the film thickness of the semiconductor thin film formed on the substrate exposed surface is made more uniform, and the film quality becomes more uniform.

Configuration plurality of support members can be arranged, the deposition chamber is configuration comprising a plurality of electrodes, and the film forming chamber can configure adopted including a plurality of.

  According to the method for producing a semiconductor thin film of the present invention, the plasma is made more uniform in the film formation region. As a result, the film thickness of the thin film formed on the substrate exposed surface is made more uniform, and the film quality is made more uniform.

FIG. 1 is a perspective view of a film forming chamber provided in the plasma CVD apparatus according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a perspective view of the substrate carrier housed in the film forming chamber of FIG. 4 is an exploded perspective view of the base carrier of FIG. FIG. 5 is a partially broken perspective view showing the positional relationship between the substrate carrier and the electrode in the film forming chamber. FIG. 6 is a partially broken perspective view showing a state inside the base carrier. FIG. 7 is a cross-sectional perspective view taken along the line BB of FIG. FIG. 8 is a cross-sectional view schematically showing the state of plasma in the film formation region. 9A is a cross-sectional view schematically showing the state of the plasma when the plasma contracts, and FIG. 9B is a cross-sectional view schematically showing the state of the plasma when the plasma protrudes on the outer peripheral surface. is there. FIG. 10 is a cross-sectional view showing a main part of a plasma CVD apparatus of a reference example . FIG. 11 is a cross-sectional view showing a main part of a plasma CVD apparatus of a reference example. FIG. 12 is a cross-sectional view showing the main part of the plasma CVD apparatus of the second embodiment. FIG. 13 is a cross-sectional view showing an example of a frame body in the first embodiment. FIG. 14 is a perspective view of a base carrier in the third embodiment of the present invention.

  A plasma CVD apparatus (semiconductor thin film manufacturing apparatus) 1 shown in FIG. 1 is of a “one-electrode double-sided discharge type” in which a film-forming surface of a substrate (base) is placed inward. As shown in FIG. 1, the plasma CVD apparatus 1 of the present embodiment (first embodiment) is configured with a film forming chamber 2 as a center, and a semiconductor thin film is formed on a desired substrate in the film forming chamber 2. To do. The film forming chamber 2 is a rectangular parallelepiped box, and a film forming chamber entrance 3 is provided in front of it. The film formation chamber entrance / exit 3 is provided with an airtight shutter, and the substrate can be taken in and out of the film formation chamber 2 by opening and closing the shutter. The film forming chamber 2 is connected to an exhaust vacuum pump, piping, a pressure control valve and the like (all not shown), and the inside of the film forming chamber 2 can be depressurized to a predetermined pressure.

As shown in FIG. 2, the film forming chamber 2 includes an electrode 5 and heaters 6a and 6b.
The electrode 5 has an elongated rectangular parallelepiped shape, is suspended from the top surface of the film formation chamber 2, and is placed vertically at the approximate center of the film formation chamber 2. There are gaps between the electrode 5 and the bottom surface of the film forming chamber 2 and between the electrode 5 and the heaters 6a and 6b. A gas inflow hole (not shown) is provided on the surface (electrode surface) of the electrode 5, and a raw material gas supply device (not shown) is connected to the gas inflow hole. Further, a high-frequency electricity supply device (not shown) is connected to the electrode 5. The electrode 5 functions as a cathode electrode.
The heaters 6 a and 6 b have an elongated rectangular parallelepiped shape and are attached to the inner wall of the film forming chamber 2. That is, the heaters 6a and 6b are positioned in parallel with the electrode 5 interposed therebetween.

  The film formation chamber 2, the electrode 5, and the heaters 6a and 6b in this embodiment are basically the same as the vacuum chamber 62, the electrode 65, and the temperature control panel 66 in the conventional plasma CVD apparatus shown in FIGS. The same thing.

  A part of the base carrier 7 is inserted into the gap between the electrode 5 and the heater 6a and the gap between the electrode 5 and the heater 6b. Here, the configuration of the base carrier 7 will be described. In FIG. 2, the detailed shape of the base carrier 7 is omitted. As shown in FIG. 3, the base carrier 7 has a shape in which two frames (support members) 8 are erected on an elongated cart so as to face each other. That is, the base carrier 7 has a rectangular parallelepiped carrier base 10 and a total of four wheels 11 are provided on both sides thereof. A rack 12 is attached to the bottom surface of the carrier base 10.

Two frame bodies (support members) 8 are provided in parallel to face each other on the long side portion on the upper surface side of the carrier base 10. There is a gap 15 between the frames 8. That is, the carrier base 10 and the two frames 8 form an upward “U” shape.
As shown in FIGS. 3 and 4, the frame body 8 is provided with a square opening 16. A large number of clips 17 are provided around the opening 16. That is, the substrate carrier 7 is provided with a total of two openings 16.

  As shown in FIGS. 3 and 4, a glass substrate (base body) 20 and a back plate 21 are attached to the frame body 8 of the base carrier 7, and the clip 17 presses them. That is, a total of two glass substrates (bases) 20 are mounted on the base carrier 7. A part of the glass substrate (base body) 20 mounted on the frame body 8 is exposed from the opening 16, and the exposed surface (base body exposed surface) 22 faces the inside of the opposing frame body 8. . In FIG. 3, the glass substrate 20 is omitted.

  The positional relationship between the substrate carrier 7 and the electrode 5 in the film forming chamber 2 of the plasma CVD apparatus 1 of this embodiment is as shown in FIG. That is, both surfaces of the electrode 5 are positioned between the two frame bodies 8, and the exposed surfaces (substrate exposed surfaces) 22 of the glass substrate 20 mounted on the frame body 8 face the electrodes 5. The electrode 5 and the exposed surface 22 of the glass substrate 20 are located in parallel to each other. Furthermore, heaters 6a and 6b are located outside the two frames 8 of the base carrier 7 (FIG. 2).

The plasma CVD apparatus (semiconductor thin film manufacturing apparatus) 1 according to this embodiment is characterized by the shape of the frame (support member) 8 on which the glass substrate (base body) 20 is mounted. As shown in FIGS. 6 and 7, a glass substrate 20 is mounted on the frame 8, and a part of the glass substrate 20 is exposed from the opening 16 to form an exposed surface 22. The frame body 8 has a planar portion 25 around the exposed surface 22. In the conventional plasma CVD apparatus, the planar portion 25 of the frame 8 is a flat surface and is flat. However, in the plasma CVD apparatus 1 of the present embodiment, the planar portion 25 is composed of an inner peripheral surface (substrate-side electrode facing surface) 26 and an outer peripheral surface (end-side electrode facing surface) 27. The peripheral surface 26 and the outer peripheral surface 27 form a step (wall) 28. The outer peripheral surface 27 protrudes inward (electrode 5 side) with respect to the inner peripheral surface 26.
Furthermore, a step portion 30 is provided between the inner peripheral portion 26 and the exposed surface 22, and the inner peripheral surface 26 protrudes inward (electrode 5 side) with respect to the exposed surface 22. Further, the step portion 30 is formed in a tapered shape whose height decreases from the inner peripheral portion 26 toward the exposed surface 22.
In FIG. 7, the back plate 21 is omitted.

Next, a method for manufacturing a semiconductor thin film by a plasma CVD method using the plasma CVD apparatus (semiconductor thin film manufacturing apparatus) of this embodiment will be described together with the action of the plasma CVD apparatus.
When a thin film is formed on the glass substrate (base) 20 by the plasma CVD apparatus 1 of the present embodiment, first, the base carrier 7 is taken out from the film formation chamber 2 and the glass substrate (base) 20 is moved to the back plate 21. Wear with. On the other hand, the shutter provided in the film formation chamber entrance / exit 30 of the film formation chamber 2 is closed, and the air in the film formation chamber 2 is exhausted and decompressed. Further, the heaters 6a and 6b are operated to raise the temperature to a predetermined temperature. Next, the base carrier 7 on which the glass substrate 20 is mounted is inserted from the film formation chamber entrance 30 and fixed so as to have a positional relationship as shown in FIGS. At this time, the substrate carrier 7 is inserted while keeping the sealed system so that the decompression in the film forming chamber 2 is not released. For example, the substrate carrier 7 is set in a transfer chamber that can be sealed with the film formation chamber entrance / exit 30, the transfer chamber is connected to the film formation chamber entrance 30, a shutter is opened, and the substrate carrier 7 is attached to the film formation chamber It can be inserted from the doorway 30. At this time, a heater may be provided in the movement chamber, and the glass substrate 20 mounted on the substrate carrier 7 may be heated in advance in the movement chamber.
Next, source gas is supplied from a gas inflow hole provided in the electrode 5, and high-frequency power is supplied to the electrode 5. Then, glow discharge is generated between the electrode 5 and the frame 8 of the substrate carrier 7 (plasma generation space) to generate plasma of source gas, and a semiconductor thin film is formed on the exposed surface 22 of the glass substrate 20. At this time, the glass substrate 20 and the frame body 8 are integrated to form one electrode (substrate support electrode 31). In other words, the frame body 8 on which the glass substrate 20 is mounted is the substrate support electrode 31. A space between the electrode 5 and the substrate support electrode 31 is a plasma generation space, and a region covering the exposed surface 22 of the glass substrate 20 in the plasma generation space is a film formation region. The substrate support electrode 31 functions as an anode electrode.

  FIG. 8 is a cross-sectional view schematically showing the state of plasma in the film formation region. As shown in FIG. 8, in this embodiment, unnecessary spread of the plasma 35 generated in the film formation region is inhibited by the step (wall) 28 formed by the inner peripheral surface 26 and the outer peripheral surface 27, The plasma 35 is confined in the film formation region. That is, the step 28 functions as a wall that shields the plasma 35. As a result, the plasma 35 becomes uniform in the film formation region, and the semiconductor thin film formed on the exposed surface 22 of the glass substrate 20 has a uniform film thickness and film quality.

Here, the case where the distance (distance between electrodes) between the electrode 5 and the substrate support electrode 31 becomes larger will be considered. The behavior may be reversed depending on the pressure region and the magnitude of the high-frequency power, but if the distance between the electrodes increases, the plasma tends to contract. However, in the present embodiment, the contraction only occurs on the inner peripheral surface 26 of the planar portion 25, and the state of the plasma 35 is as shown in FIG. 9A, and on the exposed surface 22 of the glass substrate 20. Then, the uniformity of plasma is maintained. That is, in the present embodiment, the plasma 35 in the film formation region does not become in the state as shown in FIG.
On the other hand, the case where the distance between electrodes becomes smaller will be considered. The behavior may be reversed depending on the pressure region and the magnitude of the high frequency power, but the spread of the plasma increases as the distance between the electrodes decreases. However, since there is a step (wall) 28 in this embodiment, the plasma 35 is confined in the film formation region without protruding onto the outer peripheral surface 27 as shown in FIG. In addition, when the spread of plasma is extremely large, the generated plasma 35 may protrude from the outer peripheral surface 27 beyond the inner peripheral surface 26 of the planar portion 25. However, even in this case, if there is a step (wall) 28, the amount of the plasma 35 that protrudes is small, and the state of the plasma 35 is as shown in FIG. 9B. As a result, on the exposed surface 22 of the glass substrate 20 The uniformity of the plasma 35 is maintained. That is, in the present embodiment, the plasma 35 in the film forming region does not become in a state as shown in FIG.
As described above, according to the plasma CVD apparatus 1 of the present embodiment, the uniformity of plasma in the film formation region is not greatly affected by the distance between the electrodes.

  As the height of the step 28, an appropriate height may be selected depending on the distance between the electrodes, the power and frequency of power input to the electrode 5, the pressure in the film forming chamber 2, and the like. And a range of 1/20 or more and 1/3 or less of the distance between the exposed surface 22 and the exposed surface 22. That is, in order to efficiently confine the plasma generated between the electrodes, the height of the step 28 is preferably as large as possible. However, if the outer peripheral surface 27 is too close to the electrode 5, the gap between the outer peripheral surface 27 and the electrode 5 is good. Abnormal discharge occurs, causing a major hindrance to plasma generation. On the other hand, if the height of the step is too low, the plasma cannot be confined efficiently in the film formation region. Therefore, abnormal discharge occurs between the outer peripheral surface 27 and the electrode 5 by setting the height of the step 28 to a range of 1/20 or more and 1/3 or less of the distance between the electrode 5 and the exposed surface 22. In addition, the plasma generated between the electrodes is efficiently confined in the film formation region.

In the present embodiment, a step portion 30 is provided between the inner peripheral portion 26 and the exposed surface 22, and the inner peripheral surface 26 protrudes inward (electrode 5 side) with respect to the exposed surface 22. Further, the step portion 30 is formed in a tapered shape whose height decreases from the inner peripheral portion 26 toward the exposed surface 22. As a result, plasma fluctuations are further reduced in the process from the exposed surface 22 to the inner peripheral surface 26.
The height of the stepped portion 30 is preferably as small as possible, but may be in the range of 0.5 mm or more and 4.0 mm or less, for example. That is, it is difficult to make it less than 0.5 mm in terms of the machining accuracy of the frame 8, the difficulty of processing, and the strength when holding the glass substrate 20 of the frame 8. On the other hand, if the thickness exceeds 4.0 mm, the plasma state on the planar portion 25 is affected, and the uniformity of the plasma in the film formation region may be adversely affected.

In the plasma CVD method and plasma CVD apparatus of the present invention, a higher plasma confinement effect can be obtained when the distance between the electrodes is 20 mm or less, but is not limited thereto. If the distance between the electrodes is 6 mm or less, it is generally difficult to form a step. Therefore, the actual distance between the electrodes is 6 mm to 20 mm. In this case, for example, 200 mW / cm ² or more in consideration of productivity. When the gas pressure during film formation is set to 100 Pa to 2000 Pa with the input power of 1, the plasma generated in the film formation region becomes uniform.

In the plasma CVD apparatus 1 of the first embodiment described above, although a stepped portion 30 provided on the frame (supporting member) 8 is formed in the tapered shape, an example in which the step portion 30 is not formed in a tapered shape Show. FIG. 10 is a cross-sectional view showing a main part of a plasma CVD apparatus of a reference example . In the plasma CVD apparatus (semiconductor thin film manufacturing apparatus) of FIG. 10, the stepped portion 43 of the frame (supporting member) 42 is not formed in a taper shape. It will be sufficiently uniform. The height of the stepped portion 43 may be, for example, in the range of 0.5 mm or more and 4.0 mm or less as in the first embodiment.

In the above embodiments by providing the stepped planar portions of the frame body has been confined plasma deposition region, it is also possible to confine the plasma in the deposition region by means other than stepped. FIG. 11 is a cross-sectional view showing a main part of a plasma CVD apparatus of a reference example. In the plasma CVD apparatus (semiconductor thin film manufacturing apparatus) of FIG. 11, the planar portion 47 of the frame 46 is flat and flat as in the conventional plasma CVD apparatus. The plasma is confined in the film formation region by providing a wall 48 made of a member different from the frame 46 in the plasma generation space. The member constituting the wall 48 is provided, for example, on the inner wall of the film forming chamber, and the wall 48 is formed by covering the part of the planar portion 47 with the member.

The wall 48 can also be provided directly on the planar portion of the frame. FIG. 12 is a cross-sectional view showing the main part of the plasma CVD apparatus of the second embodiment. In the plasma CVD apparatus (semiconductor thin film manufacturing apparatus) of FIG. 12, a wall 54 is provided on the planar portion 53 of the frame (supporting member) 52 to confine plasma in the film formation region.
8 to 12, the clip 17 and the back plate 21 are omitted.

  In the above-described embodiment, when a step or a wall is provided in the planar portion of the frame, the step or wall may be formed by cutting out the planar portion, or the step or wall may be formed in the flat planar portion. A member corresponding to the wall may be attached and formed. FIG. 13 is a cross-sectional view showing an example of a frame body in the first embodiment. The frame body 8 in FIG. 13 is formed by combining a first member 55 that constitutes the outer peripheral surface 27 and a second member 56 that constitutes the inner peripheral surface 26. The step 28 is formed by the first member 55 and the second member 56. The tapered step portion 30 is composed of a part of the second member 56.

  In any of the above-described embodiments, the step 28 and the walls 48 and 54 may be provided on all four sides of the exposed surface 22 of the glass substrate 20 or may be provided on some sides.

In the present embodiment, an example of the “one-electrode double-sided discharge type” in which the film formation surface of the glass substrate 20 is installed facing inward is shown. However, the film formation surface (exposed surface) of the glass substrate as shown in FIG. The configuration of the present embodiment can be applied to a plasma CVD apparatus of the type arranged facing outwards in exactly the same manner. FIG. 14 is a perspective view of a base carrier in the third embodiment of the present invention. In the embodiment shown in FIG. 14, the frame carrier 8 of the substrate carrier 57 has a positional relationship such that the heater 6 is sandwiched in the film forming chamber.
That is, the substrate carrier 57 in this embodiment is taken in and out from the upper part of the film forming chamber, and has a downward “U” shape. The base carrier 57 has two frame bodies 8, and the frame bodies 8 are provided in parallel to each other so that the planar portion 25 faces outward. That is, the mounting direction of the frame body 8 is opposite between the base carrier 7 of the first embodiment and the base carrier 57 of the present embodiment. The positional relationship between the substrate carrier 57 and the heater 6 in the film forming chamber is as shown in FIG. That is, the two frame bodies 8 are positioned so as to sandwich one heater 6, and the exposed surface 22 of the glass substrate (base body) 20 faces an electrode (not shown). The operation of the plasma CVD apparatus of this embodiment is basically the same as that of the plasma CVD apparatus 1 of the first embodiment.

  In each of the above-described embodiments, the glass substrate (base) and the electrode are arranged in the vertical direction to face each other, but they may be arranged in a direction other than the vertical direction. For example, the glass substrate (base) and the electrode may be arranged in the horizontal direction to face each other. In this case, the electrode surface may be the lower surface, the substrate exposed surface may be the upper surface, the substrate exposed surface may be the lower surface, and the electrode surface may be the upper surface. That is, the semiconductor thin film manufacturing method and the semiconductor thin film manufacturing apparatus of the present invention exert their effects regardless of the arrangement direction of the base and the electrode.

  In the embodiment described above, one glass substrate (substrate) is mounted on one frame provided on the substrate carrier, but an embodiment in which a plurality of glass substrates are mounted is also possible. In the embodiment described above, the number of substrate carriers to be installed in the film forming chamber is one, but an embodiment in which a plurality of substrate carriers can be installed is also possible. Furthermore, although the plasma CVD apparatus of the above-described embodiment has one film formation chamber, an embodiment having a plurality of film formation chambers is also possible.

  In the embodiment described above, the electrode 5 is a cathode electrode and the substrate support electrode 31 is an anode electrode. However, the opposite effect can be obtained. That is, as long as the step 28 and the walls 48 and 54 are provided, the plasma in the film formation region is uniform.

  In the above embodiment, the electrode 5 is a parallel plate electrode, but the electrode 5 may be a ladder electrode.

Producing how the semiconductor thin film of the present invention, for example, may be used in the manufacture of thin-film solar cell. That is, by forming the thus silicon-based photoelectric conversion layer in the manufacture how the semiconductor thin film of the present invention, it is possible to manufacture a thin-film solar cell having a silicon-based photoelectric conversion layer.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.

  Using the plasma CVD apparatus of the first embodiment shown in FIGS. 1 to 9, a semiconductor thin film was formed on a glass substrate under various conditions. That is, a glass substrate 20 having a length of 950 mm and a width of 980 mm was mounted on the frame body 8 of the base carrier 57 to form the base support electrode 31. The substrate support electrode 31 was introduced into the film forming chamber, and the substrate support electrode 31 was arranged to face the electrode 5. The distance between the electrodes (the distance between the surface of the electrode 5 and the exposed surface 22 of the glass substrate 20) was 9 mm. In addition, about the electrode 5 and the board | substrate support electrode 31, manufacture and assembly were performed so that those flatness might be all within 0.3 mm. As film formation conditions, the parallelism between the electrode 5 and the substrate support electrode 31 is changed to three types, and the height of the step 28 (formed by the inner peripheral surface 26 and the outer peripheral surface 27 of the frame body 8) is changed to five types. Film formation was performed under a total of 15 conditions. Here, the parallelism between the electrode 5 and the substrate support electrode 31 was set to three types of −5% to + 5%, −10% to + 10%, and −15% to + 15% of the distance between the electrodes. The height of the step 28 is k = 0 (0 times the inter-electrode distance, no step), and k = 1/20 (1 of the inter-electrode distance), where k is the ratio of the height of the step 28 to the inter-electrode distance. / 20 times), k = 1/10 (1/10 times the distance between electrodes), k = 1/5 (1/5 times the distance between electrodes), and k = 1/3 (1 times the distance between electrodes). / 3 times). In addition, the height of the step part 30 was set to a fixed value of 2 mm and formed in a tapered shape. A semiconductor thin film was formed under these conditions, and the film thickness distribution (%) of the formed semiconductor thin film was measured.

  The results are shown in Table 1. That is, when the parallelism between the electrodes is −5% to + 5%, the film thickness distribution is “± 19%” when the step 28 is not provided (k = 0), but the step 28 is provided. (K = 1/20, 1/10, 1/5, 1/3) all had good film thickness distributions of “± 10% or less”.

  Further, when the parallelism between the electrodes was slightly deteriorated to −10% to + 10%, the film thickness distribution rapidly deteriorated to “± 38%” when the step 28 was not provided (k = 0). However, when k = 1/5 and k = 1/3 in the case where the step 28 was provided, the film thickness distribution maintained a good value of “± 10% or less”. Further, when k = 1/20 and k = 1/10, the film thickness distribution was slightly deteriorated, but the degree of deterioration was small as compared with the case where the step 28 was not provided (k = 0).

  Further, when the parallelism between the electrodes was further deteriorated to −15% to + 15%, the film thickness distribution was further deteriorated to “± 50% or more” when the step 28 was not provided (k = 0). However, when the step 28 is provided and when k = 1/3, the film thickness distribution is “± 10% or less” and maintains a good value. In addition, when k = 1/20, k = 1/10, and k = 1/5, the film thickness distribution is slightly deteriorated, but the deterioration is worse than when the step 28 is not provided (k = 0). The degree was small.

  As described above, by providing the step 28 on the frame 8 of the base carrier 7, the thickness of the semiconductor thin film formed on the exposed surface 22 of the glass substrate 20 can be made uniform. This was considered to be because the plasma generated by the step 28 was confined and the plasma was made uniform in the film formation region.

It is a perspective view of the film-forming chamber with which the plasma CVD apparatus of 1st embodiment of this invention is provided. It is AA sectional drawing of FIG. It is a perspective view of the base | substrate carrier accommodated in the film-forming chamber of FIG. It is a disassembled perspective view of the base | substrate carrier of FIG. It is a partially broken perspective view which shows the positional relationship of the base | substrate carrier and electrode in a film-forming chamber. It is a partially broken perspective view which shows the state inside a base carrier. It is a BB cross-sectional perspective view of FIG. It is sectional drawing which represents typically the state of the plasma in a film-forming area | region. (A) is sectional drawing which shows typically the state of the plasma when a plasma shrinks, (b) is sectional drawing which shows typically the state of the plasma when a plasma protrudes on an outer peripheral surface. It is sectional drawing which shows the principal part of the plasma CVD apparatus of a reference example . It is sectional drawing which shows the principal part of the plasma CVD apparatus of a reference example. It is sectional drawing which shows the principal part of the plasma CVD apparatus of 2nd embodiment. It is sectional drawing which shows an example of the frame in 1st embodiment. It is a perspective view of the base | substrate carrier in 3rd embodiment of this invention. It is a longitudinal cross-sectional view which represents typically the structure of the conventional plasma CVD apparatus. It is an expanded sectional view of the principal part of the board | substrate and support member in the conventional plasma CVD apparatus. It is an expanded sectional view of the principal part of the board | substrate and support member in another conventional plasma CVD apparatus. It is a longitudinal cross-sectional view which represents typically the structure of a 1-electrode double-sided discharge type plasma CVD apparatus. It is sectional drawing which shows typically the state of the plasma in the conventional plasma CVD apparatus, (a) is an ideal state, (b) is a state in case the spread of plasma is small, (c) is the spread of plasma. (D) shows the state when the plasma contracts.

1 Plasma CVD equipment (semiconductor thin film production equipment)
2 Film forming chamber 5 Electrode 8 Frame (supporting member)
16 opening 20 glass substrate (base)
22 Exposed surface (Substrate exposed surface)
25 Planar part 26 Inner peripheral surface (substrate-side electrode facing surface)
27 Peripheral surface (surface facing the electrode on the end side)
28 steps (walls)
30 steps 42 frame (support member)
46 Frame (supporting member)
47 Planar part 52 Frame (support member)
53 Surface 54 Wall

Claims (6)

A substrate on which a semiconductor thin film is to be formed is mounted on a support member, and a part or all of the substrate is exposed from the support member, and the substrate exposed surface is opposed to the electrode surface in a film forming chamber provided with electrodes. A support member is arranged to form a plasma generation space between the support member on which the substrate is mounted and the electrode, and a high frequency power is supplied to the electrode to generate discharge, and a semiconductor thin film is formed on the substrate exposed surface A method of manufacturing a semiconductor thin film including a plasma CVD step, wherein a wall for shielding plasma is provided in the plasma generation space, and the support member is located at an outer edge of a substrate exposed surface and faces the electrode surface The planar portion is provided with the wall, the planar portion and the substrate exposed surface form a stepped portion, and the distance between the electrode surface and the planar portion is the electrode surface Smaller than the distance to the substrate exposed surface, Saga and at 0.5mm or more and 4.0mm or less, the step portion, fabrication of the semiconductor thin film characterized by being formed in a tapered shape in which the height decreases toward the planar portion on the substrate exposed surface Method. A substrate on which a semiconductor thin film is to be formed is mounted on a support member, and a part or all of the substrate is exposed from the support member, and the substrate exposed surface is opposed to the electrode surface in a film forming chamber provided with electrodes. A support member is arranged to form a plasma generation space between the support member on which the substrate is mounted and the electrode, and a high frequency power is supplied to the electrode to generate discharge, and a semiconductor thin film is formed on the substrate exposed surface A method of manufacturing a semiconductor thin film including a plasma CVD step, wherein a wall for shielding plasma is provided in the plasma generation space, and the support member is located at an outer edge of a substrate exposed surface and faces the electrode surface The surface portion is provided with the wall, and the surface portion includes a substrate side electrode facing surface adjacent to the substrate exposed surface, and a substrate exposed surface side of the substrate side electrode facing surface. An end-side electrode facing surface adjacent to the opposite side; The base-side electrode facing surface and the end-side electrode facing surface have a step where the distance between the end-side electrode facing surface and the electrode surface is smaller than the distance between the base-side electrode facing surface and the electrode surface. The wall is formed by the step , the base-side electrode facing surface and the base-exposed surface form a step, and the distance between the electrode surface and the base-side electrode facing surface is the electrode The height of the step portion is 0.5 mm or more and 4.0 mm or less, and the step portion has a height from the substrate-side electrode facing surface toward the substrate exposure surface. method of manufacturing a semi-conductor film you characterized in that it is formed in a tapered shape which becomes smaller. 3. The method of manufacturing a semiconductor thin film according to claim 2 , wherein the height of the step is 1/20 or more and 1/3 or less of a distance between the electrode surface and the substrate exposed surface. It said support member is made of a frame body having an opening, the method for manufacturing a semiconductor thin film according to any one of claims 1 to 3, characterized in that to expose a portion or all of the base from the opening. It said substrate is a plate member, a method of manufacturing a semiconductor thin film according to any one of claims 1 to 4, wherein the substrate exposed surface is a part or all of one surface of the plate member. The support member side by side a plurality of substrates mounted, to expose part or all of each of the substrate from the support member, according to claim 1 to 5, characterized in that for forming a semiconductor thin film to a plurality of base A manufacturing method of a semiconductor thin film given in any 1 paragraph.

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