JP6743727B2 - Semiconductor wafer heat treatment method and solar cell manufacturing method - Google Patents

Description

The present invention relates to a heat treatment method for performing heat treatment on a plurality of semiconductor wafers and a method for manufacturing a solar cell using the heat treatment method for semiconductor wafers.

In a general horizontal heat treatment furnace called a horizontal furnace, a semiconductor wafer heated by a heater installed outside a process tube comes into contact with a source gas to perform heat treatment. The heater is divided into a plurality of zones in the axial direction of the process tube so that the heat treatment is uniformly performed on the plurality of semiconductor wafers, and an appropriate electric power is supplied to each zone.

However, the source gas introduced from one end of the process tube is introduced at a temperature close to room temperature, which causes a decrease in the semiconductor wafer temperature. Therefore, at one end of the semiconductor wafer group installed on the gas introduction side in the process tube, there is a problem that the temperature of the semiconductor wafer is lowered by the introduced gas and the heat treatment is not uniformly performed.

Therefore, in order to solve the above problem, a heat treatment furnace has been proposed in which a preheater is arranged at a position adjacent to the gas introduction side of a horizontal furnace to raise the temperature of the introduced gas (Patent Document 1).

JP-A-5-94980

However, in the heat treatment furnace described in Patent Document 1, since the semiconductor wafer is installed perpendicularly to the axis of the process tube, the supply of the raw material gas to the central portion of the semiconductor wafer is insufficient, and in the plane of the semiconductor wafer. However, there is a problem that the heat treatment is not performed uniformly. Further, in a plurality of semiconductor wafers arranged in the axial direction of the process tube, the temperature of the semiconductor wafer on the gas introduction side is lowered, and thus there is a problem that the temperature uniformity among the plurality of semiconductor wafers is lowered.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a heat treatment method for a semiconductor wafer and a method for manufacturing a solar cell, which perform heat treatment with excellent uniformity using a heat treatment furnace. To do.

In order to solve the above problems and achieve the object, a semiconductor wafer heat treatment method of the present invention is a semiconductor wafer installation step of installing a plurality of semiconductor wafers in a cylindrical process tube in parallel with the axis of the process tube. A heat treatment step of heat-treating a semiconductor wafer by heating the process tube while supplying a raw material gas from a gas introduction port provided at one end of the process tube. Between the semiconductor wafer and the semiconductor wafer, it has a plurality of partition plates arranged perpendicular to the axis of the process tube and in contact with the inner circumference of the process tube, and the source gas is supplied through the openings provided in the partition plate to provide a plurality of partition plates. The plates are installed in this order from the gas inlet side to the inlet side first partition plate, the inlet side second partition plate, the central opening partition plate, and the wafer side partition plate, and the inlet side first partition plate is installed on the gas inlet side. The first partition plate has a first opening formed between itself and the inner circumference of the process tube by the notch at the first position of the end portion in the circumferential direction, and the second partition plate on the inlet side is the end portion in the circumferential direction. Is provided with a second opening formed between the inner circumference of the process tube and a notch at a second position different from the first position, and the central opening partition plate has one central opening formed at the central portion. The wafer-side partition plate is provided with a plurality of dispersion openings for distributing the raw material gas .

According to the present invention, by promoting the supply of the source gas to the central portion of the semiconductor wafer, the uniformity of the heat treatment in the plane of the semiconductor wafer is improved, and a plurality of semiconductors arranged in the axial direction of the process tube are provided. By improving the temperature uniformity between the wafers, the uniformity of the heat treatment between the semiconductor wafers can be improved.

FIG. 1 is a sectional view of a heat treatment furnace used in the first embodiment. FIG. 2 is a perspective view showing a main part of the process tube used in the first embodiment. FIG. 3 is a plan view of the inlet side first partition plate 11 viewed from the axial direction of the process tube. FIG. 4 is a plan view of the introduction port side second partition plate 21 viewed from the axial direction of the process tube. FIG. 5 is a plan view of the central opening partition plate 31 seen from the axial direction of the process tube. FIG. 6 is a plan view of the wafer side partition plate 41 viewed from the axial direction of the process tube. FIG. 7 is a cross-sectional view of the process tube 1 at a position where the semiconductor wafer 5 is installed in a direction perpendicular to the axial direction. FIG. 8 is a plan view of the wafer side partition plate 51 used in the second embodiment as seen from the axial direction of the process tube 1. FIG. 9 is a plan view of the wafer side partition plate 61 used in the third embodiment as seen from the axial direction of the process tube 1.

1 process tube, 2 gas introduction port, 3 exhaust port, 4 semiconductor wafer installation boat, 5 semiconductor wafer, 6 heater, 7 soaking area, 8 heat treatment furnace, 9 gas introduction end, 11 introduction port side first partition plate, 12 1st opening, 21 2nd opening side partition plate, 22 2nd opening, 31 Central opening partition plate, 32 Central opening, 41 Wafer side partition plate, 42 Dispersion opening, 51 Wafer side partition plate, 52 Dispersion opening, 61 Wafer side partition plate, 62 distributed openings

Exemplary embodiments of a heat treatment method for a semiconductor wafer and a method for manufacturing a solar cell using the heat treatment method for a semiconductor wafer according to the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments, and can be changed as appropriate without departing from the gist of the present invention. Further, in the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of a heat treatment furnace 8 used in the heat treatment method according to the first embodiment of the present invention. FIG. 2 is a perspective view showing a main part of the process tube 1 used in the heat treatment method according to the first embodiment of the present invention. As shown in FIGS. 1 and 2, the heat treatment furnace 8 according to the embodiment has a cylindrical process tube 1 made of quartz glass and a cylindrical heater 6 arranged on the outer periphery of the process tube 1. The process tube 1 has a cylindrical shape having the same cross-sectional shape in the axial direction, has heat resistance, and a source gas is flown inside. One end of the process tube 1 is closed by a gas introduction end 9. A gas introduction port 2 for introducing the raw material gas is provided at the gas introduction end portion 9, and a gas introduction pipe is connected to the gas introduction port 2. The other end of the process tube 1 is an open end for disposing the semiconductor wafer 5 in the process tube 1, and a door is installed so as to be openable and closable. A gas outlet 3 is provided at the peripheral portion of the open end of the process tube 1.

In the heat treatment furnace 8 according to the present embodiment, a plurality of semiconductor wafers 5 are set on the quartz glass semiconductor wafer setting boat 4 and inserted into the process tube 1. The semiconductor wafer 5 is installed parallel to the axial direction of the process tube 1. Here, the semiconductor wafer 5 is, for example, a silicon substrate for manufacturing a solar cell. A plurality of semiconductor wafers 5 are installed side by side in a small boat in parallel with the axial direction of the process tube 1, and further, a plurality of small boats are arranged in the axial direction of the process tube 1 and installed on the semiconductor wafer installation boat 4. ..

A heater 6 is installed on the outer peripheral portion of the process tube 1 so as to surround the soaking area 7 of the semiconductor wafer 5. The soaking area 7 of the semiconductor wafer 5 is an area in the process tube 1 where the semiconductor wafer 5 is arranged.

A gas introduction port 2 for introducing a raw material gas is provided on the gas introduction end 9 side of the process tube 1, and a mixed gas of nitrogen, oxygen, phosphorus oxychloride and the like is supplied from there as a raw material gas, It flows in the direction of the arrow and is exhausted from the exhaust port 3.

Between the semiconductor wafer installation boat 4 and the gas introduction end portion 9, there is a gas introduction side space that does not interfere with the semiconductor wafer installation boat 4 and the semiconductor wafer 5, and the gas introduction side space is also affected by the heater 6 and becomes high temperature. Has become. A plurality of partition boards are installed there.

In FIG. 2, only the process tube 1, the semiconductor wafer 5, the first opening 11, the inlet side second partition plate 21, the central opening partition plate 31, and the wafer side partition plate 41 of the heat treatment furnace 8 are illustrated in a perspective view. ing. A plurality of semiconductor wafers 5 are arranged side by side in parallel with the axial direction of the process tube 1, and a plurality of semiconductor wafers 5 are arranged in parallel with the axial direction of the process tube 1 as one set. It is installed.

The partition plate is made of quartz and is fixed by welding to the inner circumference of the process tube 1. Alternatively, a partition plate connecting member may be arranged between the partition plates and welded to fix a plurality of partition plates, and the partition plates may be installed in the gas introduction side space in the process tube 1.

The partition plate is provided between the semiconductor wafer installation boat 4 and the gas introduction port 2 from the gas introduction port 2 side from the introduction port side first partition plate 11A, the introduction port side second partition plate 21A, the introduction port side first partition plate. The plate 11B, the inlet-side second partition plate 21B, the central opening partition plate 31, and the wafer-side partition plate 41 are arranged in this order vertically to the axial direction of the process tube 1 and parallel to each other at equal intervals. The partition plate has a thickness of, for example, 3 mm, and the partition plate has an interval of, for example, 20 mm.

FIG. 3 shows a plan view of the introduction port side first partition plates 11A and 11B viewed from the axial direction of the process tube 1. The first partition plates 11A and 11B have the same shape. The inlet-side first partition plate 11A is installed at a position closest to the gas inlet 2 among the plurality of partition plates. The inlet-side first partition plates 11A and 11B are made of quartz and have a disk-shaped outer shape whose outer diameter is equal to the inner diameter of the process tube 1. A part of the circumference is cut linearly to form a D-shape. By having the first D-type cutting portion and the first D-type cutting portion as the lower portion which is the first position of the end portion in the circumferential direction and installing the same in the process tube, the space between the lower portion of the inner circumference of the process tube 1 is reduced. The first opening 12 is formed in. In FIG. 3, the process tube 1 is shown by a broken line. Although the configuration in which the first position is provided in the lower portion has been described, the first position is not limited to the lower portion. It may be located at any position as long as it is an end portion in the circumferential direction.

FIG. 4 shows a plan view of the inlet side second partition plates 21A and 21B viewed from the axial direction of the process tube 1. The second partition plates 21A and 21B have the same shape. The inlet-side second partition plates 21A and 21B are made of quartz and have a disk-shaped outer shape whose outer diameter is equal to the inner diameter of the process tube 1. A part of the circumference is cut linearly to form a D-shape. And a second D-type cutting portion, and by installing the second D-type cutting portion in the process tube as an upper portion which is the second position of the end portion in the circumferential direction, between the inner peripheral upper portion of the process tube 1 and The second opening 22 is formed in. In FIG. 4, the process tube 1 is shown by a broken line. Although the configuration in which the second position is provided on the upper part has been described, the second position is not limited to the upper part. It suffices that the second opening 22 is provided at a position different from the first position of the end portion in the circumferential direction of the process tube and does not overlap the first opening 12 when viewed from the axial direction of the process tube. More preferably, the first opening 12 and the second opening 22 are displaced by 90° or more in the circumferential direction. Most preferably, the first opening 12 and the second opening 22 are offset by 180° in the circumferential direction.

FIG. 5 shows a plan view of the central opening partition plate 31 seen from the axial direction of the process tube 1. The central opening partition plate 31 is made of quartz and has a disk shape with an outer diameter equal to the inner diameter of the process tube 1, and one central opening 32 is formed in the central portion of the disk.

FIG. 6 shows a plan view of the wafer side partition plate 41 viewed from the axial direction of the process tube 1. The wafer-side partition plate 41 is made of quartz and has a disk shape with an outer diameter equal to the inner diameter of the process tube 1. The wafer-side partition plate 41 is evenly arranged on the entire surface of the disk and has a cross section of the source gas perpendicular to the axial direction of the process tube 1. There are a plurality of dispersion openings 42 distributed throughout The wafer-side partition plate 41 is arranged at the position closest to the semiconductor wafer 5 among the partition plates installed in parallel at a plurality of intervals.

FIG. 7 shows a cross-sectional view of the process tube 1 at a position where the semiconductor wafer 5 is installed, in a direction perpendicular to the axial direction. A plurality of semiconductor wafers 5 are arranged side by side in parallel with the axial direction of the process tube 1 and in the direction perpendicular thereto. A soaking region 7 is formed so as to surround the semiconductor wafer 5. The process tube 1 has a cylindrical shape with an inner diameter of 250 mm, for example. The semiconductor wafer 5 has, for example, a square shape with one side of 156 mm and a flat plate shape with a thickness of 0.2 mm. Forty-one semiconductor wafers 5 are arranged in parallel at an interval of 3.5 mm.

Next, the flow of the raw material gas in FIG. 1 will be described. The raw material gas is introduced into the process tube 1 through the gas introduction port 2. The introduced raw material gas collides with the inlet side first partition plate 11A arranged on the gas inlet end 9 side and passes through the first opening 12A formed in the lower part of the inlet side first partition plate 11A. , Flows upward in the space formed between the inlet-side first partition plate 11A and the inlet-side second partition plate 21A.

Next, the raw material gas passes through the second opening 22A formed in the upper part of the inlet side second partition plate 21A and is formed between the inlet side second partition plate 21A and the inlet side first partition plate 11B. Flows downward into the designated space.

Next, the raw material gas passes through the first opening 12B formed in the lower part of the inlet side first partition plate 11B and is formed between the inlet side first partition plate 11B and the inlet side second partition plate 21B. Flows upward into the designated space. In FIG. 1, the introduction side first partition plate 11 and the introduction side second partition plate 21 are described as one set, and two sets are arranged side by side in the axial direction of the process tube 1, but the present invention is not limited to this. It is not limited. One set may be used as shown in FIG. Alternatively, there may be three or more sets.

Next, the raw material gas passes through the second opening 22B formed in the upper portion of the inlet-side second partition plate 21B, and the space formed between the inlet-side second partition plate 21B and the central opening partition plate 31. Flows downwards.

Next, the source gas flows through the central opening 32 provided in the central portion of the central opening partition plate 31 into the space formed between the central opening partition plate 31 and the wafer side partition plate 41.

Next, the raw material gas is distributed to the entire cross section perpendicular to the axial direction of the process tube 1 through a plurality of dispersion openings 42 provided evenly over the entire surface of the wafer side partition plate 41, and flows into the soaking region 7. ..

The first embodiment of the present invention is used in a diffusion furnace that performs thermal diffusion processing by performing heat treatment while flowing a source gas containing an impurity diffusion source. As an example of a thermal diffusion process in which a diffusion process is performed in a heat treatment furnace, when diffusing n-type impurity phosphorus (P) into a semiconductor wafer of silicon (Si), phosphorus oxychloride (POCl ₃ ) is vaporized to nitrogen gas. And mixed with oxygen gas to obtain the raw material gas. The reaction formula is as follows.
2POCl ₃ +(3/2)O ₂ →P ₂ O ₅ +3Cl ₂ (1)
P ₂ O ₅ +(5/2)Si→2P+(5/2)SiO ₂ (2)

The chemical reactions of the above formulas (1) and (2) are performed in a furnace at 800°C to 1000°C.

When a plurality of semiconductor wafers 5 are arranged in the process tube 1 and heat diffusion processing is performed at the same time, the uniformity of diffusion can be improved by performing the treatment on the plurality of semiconductor wafers 5 under the same conditions. .. Conditions that affect the thermal diffusion process include the processing temperature and the amount of raw material gas supplied. By uniformizing the processing temperature for the plurality of semiconductor wafers 5, the uniformity of the heat treatment is improved.

Further, by uniformizing the supply amount of the raw material gas to the plurality of semiconductor wafers 5, the uniformity of the thermal diffusion process is improved. Regarding the supply amount of the source gas, the uniformity of the supply amount of the source gas is improved by making the flow velocity distribution uniform in the cross section perpendicular to the axial direction of the process tube 1 when the source gas is supplied.

In the first embodiment of the present invention, the position where the first opening 12 of the inlet-side first partition plate 11 and the second opening 22 of the inlet-side second partition plate 21 do not overlap when viewed in the axial direction of the process tube 1. It is provided in. The raw material gas flows between the first inlet-side partition plate 11 and the second inlet-side partition plate 21 from the first opening 21 to the second opening 22 in a direction perpendicular to the axial direction of the process tube 1. Since the raw material gas is caused to flow in the direction perpendicular to the axial direction of the process tube 1 by providing the opening portion in this way, the time for flowing through the space heated by the heater 6 becomes longer, so that the raw material gas is compared to the case without the partition plate. The temperature of the gas becomes high, and the temperature drop in the soaking region 7 can be suppressed.

In addition, by arranging the first opening 12 and the second opening 22 at positions shifted by 180° in the circumferential direction, the raw material gas is separated from the introduction port side first partition plate 11 and the introduction port side second partition plate 21. The distance flowing from the first opening 12 to the second opening 22 can be made the longest.

Further, in the first embodiment of the present invention, the source gas is installed at the first position and the second position because the inlet side first partition plate 11 and the inlet side second partition plate 21 are installed adjacent to each other. By shifting by 90° or more in the circumferential direction, it is possible to further lengthen the time of flowing through the space heated by the heater 6. By shifting the first position and the second position by 180° in the circumferential direction, it is possible to maximize the time for flowing through the space heated by the heater 6.

Further, in the present invention, the semiconductor wafer 5 is installed parallel to the axial direction of the process tube 1, and the introduced gas easily passes between the semiconductor wafers, so that there is an effect that the uniformity in the plane of the semiconductor wafer is improved. .. Further, there is an effect that the uniformity is improved between the small boats arranged in the axial direction of the process tube 1.

Further, in the first embodiment of the present invention, in the wafer side partition plate 41 provided on the side closest to the soaking area 7, a plurality of dispersion openings 42 are evenly provided on the entire surface of the wafer side partition plate 41. Therefore, there is an effect that the raw material gas is evenly distributed in the plurality of dispersion openings 42, is distributed over the entire cross section of the process tube 1 perpendicular to the axial direction, and is flowed to the soaking region 7. This makes it possible to make the flow velocity distribution of the raw material gas in the cross section perpendicular to the axial direction of the process tube 1 uniform over the entire cross section, so that a plurality of the process tubes 1 are arranged in parallel to the direction perpendicular to the axial direction. In the semiconductor wafer 5, the uniformity between semiconductor wafers can be improved.

Further, in the first embodiment of the present invention, since the central opening partition plate 31 is provided on the upstream side adjacent to the wafer side partition plate 41, the wafer side partition plate 41 is evenly distributed to the plurality of dispersion openings 42. It has the effect of dispersing the raw material gas.

According to the present invention, by promoting the supply of the source gas to the central portion of the semiconductor wafer, the uniformity of the heat treatment in the plane of the semiconductor wafer is improved, and a plurality of process tubes 1 are arranged in the axial direction. By improving the temperature uniformity between semiconductor wafers, the uniformity of heat treatment between semiconductor wafers can be improved.

Embodiment 2.
The second embodiment is different from the first embodiment in the shape of the wafer side partition plate. The other configuration is the same as that of the first embodiment. FIG. 8 shows a plan view of the wafer side partition plate 51 used in the second embodiment as seen from the axial direction of the process tube 1. The wafer-side partition plate 51 is arranged at a position closest to the semiconductor wafer 5 among the partition plates that are installed in parallel at a plurality of intervals.

The wafer-side partition plate 51 is made of quartz and has a disk shape with an outer diameter equal to the inner diameter of the process tube 1, and slit-shaped dispersion openings 52 are provided in a region corresponding to the soaking region 7. The dispersion opening 52 has a rectangular shape having, for example, a vertical direction of 156 mm, which is the same as one side of the semiconductor wafer 5, and a horizontal direction of 10 mm. The inter-opening holding portion between the openings is 10 mm, and eight openings are provided. They are arranged side by side in the horizontal direction. By arranging the eight openings and the seven inter-opening holding portions in the horizontal direction, the openings are provided in a region corresponding to the soaking region 7 of 156 mm in the vertical direction and 150 mm in the horizontal direction. In this case, the aperture ratio of the dispersion openings 52 in the soaking region 7 is about 50%. Further, the opening ratio of the dispersion openings 52 with respect to the cross section of the process tube 1 in the direction perpendicular to the axial direction is about 25%.

The first opening 12 of the inlet-side first partition plate 11, the second opening 22 of the inlet-side second partition plate 21, and the central opening 32 of the central opening partition plate 31 are perpendicular to the axial direction of the process tube 1. It is desirable that the aperture ratio with respect to the cross section of the above is approximately the same as the aperture ratio of the dispersion aperture 52.

In the second embodiment, since the opening is provided only in the region corresponding to the soaking region 7, the source gas mainly flows into the soaking region 7, so that the source gas is efficiently supplied to the semiconductor wafer 5. There is an effect.

Further, by making the openings and the inter-opening holding portions to have the same length, there is an effect that the strength of the wafer side partition plate 51 is maintained. Further, by making the openings and the inter-opening holding portions have the same length, it is possible to obtain an opening ratio of 50%. That is, by making the openings and the opening-to-opening holding portions have the same length, it is possible to obtain a high opening ratio while ensuring strength. By increasing the aperture ratio, it is possible to equalize the in-plane flow rate distribution of the source gas in the cross section of the process tube 1 in the direction perpendicular to the axial direction.

Embodiment 3.
The third embodiment is different from the first embodiment in the shape of the wafer side partition plate. The other configuration is the same as that of the first embodiment. FIG. 9 shows a plan view of the wafer side partition plate 61 used in the third embodiment as seen from the axial direction of the process tube 1. The wafer-side partition plate 61 is arranged at a position closest to the semiconductor wafer 5 among the partition plates that are installed in parallel at a plurality of intervals.

The wafer-side partition plate 61 is made of quartz and has a disk shape with an outer diameter equal to the inner diameter of the process tube 1. In the area corresponding to the soaking area 7, a plurality of circular dispersion openings 62 are arranged in a staggered manner. It The dispersion openings 62 have a circular shape with an outer diameter of 10 mm, and are provided with inter-opening holding portions of 10 mm to be arranged in the horizontal direction and arranged by the width of the soaking area 7. In the vertical direction, the centers of the vertically adjacent openings are arranged so as to be horizontally displaced by half the pitch between the openings, and the centers of the openings are arranged at a height of 60° with respect to the vertical direction. At this time, the inter-opening holding portions of the vertically adjacent openings have the same length as the inter-opening holding portions of the left and right adjacent openings. As a result, the dispersion openings 62 are arranged such that the center position thereof is an equilateral triangle. These are arranged in the vertical direction and arranged by the height of the soaking area 7. By arranging in this way, an opening is provided in a region corresponding to the soaking region 7 of 156 mm in the vertical direction and 150 mm in the horizontal direction. In this case, the aperture ratio of the dispersion opening 62 in the soaking area 7 is 23%. Further, the opening ratio of the dispersion openings 62 with respect to the cross section of the process tube 1 in the direction perpendicular to the axial direction is about 12%.

The first opening 12 of the inlet-side first partition plate 11, the second opening 22 of the inlet-side second partition plate 21, and the central opening 32 of the central opening partition plate 31 are perpendicular to the axial direction of the process tube 1. It is desirable that the aperture ratio with respect to the cross section of 1 is approximately the same as the aperture ratio of the dispersion aperture 62.

In the third embodiment, since the opening is provided only in the region corresponding to the soaking region 7, the source gas mainly flows into the soaking region 7, so that the source gas is efficiently supplied to the semiconductor wafer 5. There is an effect. Further, by setting the lengths of the opening and the holding portion between openings to be approximately the same, there is an effect that the strength of the wafer side partition plate 61 is maintained. In addition, by forming the openings in a zigzag arrangement of 60°, an aperture ratio of 23% can be obtained.

In the third embodiment, the openings and the inter-opening holding portions have the same length, and the rows are horizontally shifted by a half of the inter-opening pitch, so that the rows at the certain height positions are adjacent to each other in the horizontal direction. It becomes the inter-opening holding portion of the matching row, and the horizontal inter-opening holding portion of the row at a certain height position becomes the opening position of the adjacent row. That is, since openings can be provided at respective positions in the horizontal direction, there is an effect that the source gas is efficiently supplied to the semiconductor wafer 5.

Fourth Embodiment
A fourth embodiment of the method for manufacturing a solar cell of the present invention will be described. To manufacture a solar cell, for example, a p-type silicon wafer to which boron (B) is added is diffused with phosphorus using the heat treatment method of the above-described first embodiment, and an n-type layer is formed on the wafer surface. Form. As a result, a pn junction is formed on the surface of the p-type silicon wafer, and photovoltaic power can be generated by sunlight. In order to extract the electric current generated by the photovoltaic power, a plurality of thin wire electrodes are formed on the n-type layer and a back surface electrode is formed on the entire back surface of the wafer. An antireflection layer or the like may be formed on the n-type layer to improve light utilization efficiency. In order to manufacture a solar battery module, a plurality of solar battery cells may be arranged on a glass substrate, electrical wiring may be performed, and sealing may be performed with EVA resin or the like.

According to the present invention, in the method for manufacturing a solar battery cell, since a semiconductor wafer that has been uniformly heat-treated can be used, there is an effect that a uniform solar battery cell can be obtained.

As described above, the heat treatment method according to the present invention is useful as a heat treatment method for performing heat treatment on a plurality of semiconductor wafers.

Claims (4)

A semiconductor wafer installation step of installing a plurality of semiconductor wafers in a cylindrical process tube in parallel with the axis of the process tube;
A heat treatment method comprising a heat treatment step of heat treating the semiconductor wafer by heating the process tube while supplying a source gas from a gas inlet provided at one end of the process tube,
Between the gas inlet and the semiconductor wafer, it is arranged perpendicular to the axis of the process tube, has a plurality of partition plates in contact with the inner circumference of the process tube, through the opening provided in the partition plate Supply raw material gas ,
The plurality of partition plates are installed in this order from the gas inlet side to the inlet side first partition plate, the inlet side second partition plate, the central opening partition plate, and the wafer side partition plate.
The inlet side first partition plate installed on the gas inlet side includes a first opening formed between the inner periphery of the process tube and a notch at the first position of the end portion in the circumferential direction,
The introduction-side second partition plate includes a second opening formed between the inner periphery of the process tube by a notch at a second position different from the first position at the end in the circumferential direction,
The central opening partition plate is provided with one central opening formed in the central portion,
The heat treatment method for a semiconductor wafer, wherein the wafer-side partition plate is provided with dispersion openings that are a plurality of openings for dispersing the raw material gas . 2. The heat treatment method for a semiconductor wafer according to claim 1 , wherein the dispersion opening is provided in a region corresponding to a soaking region which is a region in which the semiconductor wafer is installed. The raw material gas comprises impurity diffusion source, the heat treatment method of semiconductor wafer of claim 1 or 2, characterized in that the diffusion treatment by the heat treatment. A method of manufacturing a solar cell, comprising: forming an impurity diffusion layer on the plurality of semiconductor wafers by the heat treatment method according to claim 3 ; and forming a pn junction inside the plurality of semiconductor wafers.

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