JP2007080975A - Method and equipment of manufacturing spherical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a uniform diffusion layer in the surface of a spherical semiconductor. <P>SOLUTION: In a cylindrical reaction vessel having an inlet for introducing raw gas and an outlet for discharging the processed gas, a method of manufacturing a spherical semiconductor device for forming a diffusion layer wherein the impurities in the raw gas are diffused in the surface of a spherical semiconductor is carried out such that a spherical semiconductor may be flowed/rotated by rocking or rotating the reaction vessel. It is preferable to combine a rocking process wherein the reaction vessel is made to move reciprocately in a vertical direction for at least one side of the front and rear parts, and a rotation process wherein the reaction vessel is made to rotate around the axial center or a vibration process for giving vibration to the reaction vessel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for manufacturing a spherical semiconductor element, particularly a photoelectric conversion element, and more particularly to a diffusion method and apparatus for forming a diffusion layer on the surface of a spherical semiconductor.

  As a clean energy source, a photoelectric conversion device has attracted attention. A typical photoelectric conversion device uses an element made of a crystalline silicon semiconductor wafer and uses a semiconductor layer made of amorphous silicon. In the former, the process from the production of the single crystal ingot and the production of the semiconductor wafer from the single crystal ingot is complicated, and the utilization rate of the expensive silicon raw material is low due to the cutting scraps of the crystal, resulting in high cost. The latter has a problem in that the amorphous structure in which hydrogen is bonded to the dangling bonds of silicon is likely to undergo structural change due to the release of hydrogen by light irradiation, so that the photoelectric conversion efficiency is gradually lowered by light irradiation.

As a photoelectric conversion device that does not have the above-described characteristic deterioration, is inexpensive, and can be expected to have high output, a device using a spherical photoelectric conversion element in which an n-type semiconductor layer is formed on the surface of a spherical p-type semiconductor has been studied. Yes. This photoelectric conversion device uses a small spherical element having a diameter of about 1 mm, thereby reducing the average thickness of the entire photoelectric conversion unit and reducing the amount of raw material Si used.
As this type of photoelectric conversion device, there is known a device in which a spherical photoelectric conversion element having a diameter of about 1 mm is attached to each concave portion of a support having a large number of concave portions, and the inner surface of the concave portion serves as a reflecting mirror (Patent Document). 1 and 2). According to such a configuration, it is possible to reduce the amount of element material, particularly expensive Si, and to irradiate the element with 4 to 6 times the light directly irradiated to the element by the action of the reflecting mirror. It has the advantage that light can be used effectively.

Said photoelectric conversion element is produced as follows, for example.
First, a p-type polycrystalline Si lump containing a very small amount of boron is supplied into a crucible and melted in an inert gas atmosphere. The melt is dropped from a minute nozzle hole at the bottom of the crucible, and the droplet is cooled and solidified during natural fall. Thus, a polycrystalline or single crystal spherical p-type semiconductor is produced.
Next, after polishing the surface of the spherical p-type semiconductor and further removing about 50 μm of the surface layer by etching or the like, for example, heat treatment is performed at 800 to 950 ° C. for 10 to 30 minutes using phosphorus oxychloride as a diffusion source. As a result, an n-type semiconductor layer having a thickness of about 0.5 μm in which phosphorus is diffused on the surface of the p-type semiconductor is formed as the second semiconductor layer.

Conventionally, in order to form a second semiconductor layer by diffusing phosphorus on the surface of the spherical first semiconductor as described above, a processing apparatus for performing a diffusion process or a film forming process on a wafer such as silicon is used. It was. The apparatus used for manufacturing this type of semiconductor device has been improved so that the supply of the processing gas and the temperature control can be performed with high precision. Basically, the object to be processed is left still on the boat ( For example, Patent Document 3). Therefore, even if the boat is moved intermittently, it is difficult to form a uniform diffusion layer on the surface of many spherical elements.
JP 2002-164554 A JP 2004-63564 A JP-A-6-246261

  In view of the above, an object of the present invention is to provide a method and an apparatus capable of forming a uniform diffusion layer on the surface of a spherical semiconductor.

  In the method for manufacturing a spherical semiconductor element of the present invention, impurities in the processing gas are diffused on the surface of the spherical semiconductor in a cylindrical reaction vessel having an introduction port for introducing the processing gas and an exhaust port for discharging the gas. A method for producing a spherical semiconductor element for forming a diffusion layer, comprising the step of causing the spherical semiconductor to flow and rotate in the reaction vessel by swinging or rotating the reaction vessel.

  The present invention relates to a spherical semiconductor in which a diffusion layer is formed by diffusing impurities in a processing gas on the surface of a spherical semiconductor in a cylindrical reaction vessel having an introduction port for introducing a processing gas and an exhaust port for discharging the gas. A method for manufacturing an element, comprising: a step of replacing a spherical semiconductor in a reaction vessel from the front to the rear and a portion from the rear to the front; and a step of dispersing the spherical semiconductor in a space in the reaction vessel An element manufacturing method is provided.

Here, the step of replacing the spherical semiconductor in the reaction vessel from the front to the rear and from the rear to the front is performed by a rocking step in which at least one of the front and rear portions of the reaction vessel reciprocates vertically. Can do. Instead of the step of rocking the reaction vessel, for example, by rotating the reaction vessel installed so that one of the front and rear portions is in the upper position around its axis, the rib provided on the inner wall of the reaction vessel The lower semiconductor in the reaction vessel can be moved to the upper part in the reaction vessel. The semiconductor moved to the upper part in the reaction vessel moves to the lower part along the inner wall surface of the reaction vessel by gravity.
The step of spraying the spherical semiconductor into the space in the reaction vessel involves rotating the reaction vessel around its axis to push the semiconductor in the direction of rotation by the rib provided on the inner wall of the reaction vessel, It can be carried out by dropping the semiconductor from

According to the present invention, since the spherical semiconductor flows and rotates due to the swinging or rotation of the reaction vessel, the degree of contact with the processing gas is better than when the reaction is merely performed in a stationary state. Therefore, a substantially uniform diffusion layer can be formed.
In addition, by replacing the spherical semiconductor in the reaction vessel from the front part to the rear part and from the rear part to the front part, the one close to the processing gas inlet side and the one far from the processing gas are mixed with each other. Due to the flow of the semiconductor in the reaction vessel before and after in the reaction vessel, there is almost no difference in the contact state between the semiconductor gas near the processing gas inlet and the semiconductor gas far from the processing gas. Furthermore, since the individual semiconductors are also temporarily separated by the step of dispersing the spherical semiconductors into the space in the reaction vessel, the entire surface of the semiconductors can be uniformly contacted with the processing gas.

  The present invention does not divert a conventional apparatus for processing a wafer to diffuse a impurity on the surface of a spherical first semiconductor to form a second semiconductor layer, and the first semiconductor is spherical. By taking advantage of this, it is possible to obtain a high-quality semiconductor element by continuously reacting in a fluid state. In other words, the manufacturing method of the present invention causes a large number of spherical semiconductors accommodated in the reaction vessel to flow and rotate by swinging or rotating the reaction vessel so that the contact degree with the processing gas is good and almost uniform. It is intended to form a simple diffusion layer.

In a preferred first embodiment of the present invention, impurities in a processing gas are diffused on the surface of a spherical semiconductor in a cylindrical reaction vessel having an inlet for introducing a processing gas and an outlet for discharging the gas. A method of manufacturing a spherical semiconductor element, in which a diffusion layer is formed, and includes a swinging step in which at least one of the front and rear portions of the reaction vessel reciprocates in the vertical direction.
When the above-described swinging process is taken, a large number of spherical semiconductors accommodated in the reaction vessel are separated from those on the processing gas inlet side and those on the outlet side (including those far from the inlet side). They are mixed or the one on the inlet side is replaced with the outlet side, and the one on the outlet side is replaced with the inlet side. As the spherical semiconductor flows before and after the reaction vessel in this way, there is almost no difference in the contact state with the processing gas between the inlet side and the outlet side of the reaction vessel. In addition, since the semiconductor flows and rotates, the degree of contact with the processing gas does not vary locally on the surface of the semiconductor.

Preferably, the method further includes a rotating step of rotating the reaction vessel around its axis. This rotating step is preferably performed in parallel with the swinging step.
In the rotation process in which the reaction vessel rotates around its axis, the spherical semiconductor flows and rotates, so that the degree of contact with the processing gas does not differ locally on the surface. Furthermore, since the semiconductors flow and rotate in different directions in the rotating step and the swinging step, the degree of contact with the processing gas on the surface of the semiconductor becomes more uniform.

In the first embodiment, the reaction vessel has at least one rib extending on the inner wall surface from one end side to the other end side and projecting toward the inside of the reaction vessel. Is preferred.
The rib pushes up the spherical semiconductor in the rotation direction as the reaction vessel rotates, and the semiconductor falls into the space in the reaction vessel when the rib cannot support the semiconductor. In this way, the spherical semiconductor is dispersed in the space as the reaction vessel rotates, and thus the individual semiconductors are also temporarily separated, so the degree of contact with the processing gas locally on the surface of the semiconductor. There is no difference.

  A preferred semiconductor device manufacturing apparatus for carrying out the method of the first embodiment includes a swing plate pivotally supported on a base, and connected to a front portion or a rear portion of the swing plate. A swinging plate driving unit that reciprocates the plate up and down, a heating block that is fixed to the swinging plate and includes heating means therein, a cylindrical reaction vessel located in the heating block, and connected to the reaction vessel A support portion extending out of the heating block through the opening of the heating block, a rotation driving portion for rotating the reaction vessel around its axis, and a processing gas supply device for supplying a processing gas to the reaction vessel And a gas discharge device for discharging the gas from the reaction vessel.

In this apparatus, a swing plate is pivotally supported on a base, and a heating block is fixed to the swing plate. The reaction vessel heated in the heating block is rotated by the rotation drive unit. The swing plate driving unit is provided on the base, and the rotation driving unit of the reaction vessel is provided on the swing plate. As described above, since the base, the swing plate, the swing plate drive unit, the heating block, and the rotation drive unit of the reaction vessel are optimally arranged, the entire apparatus can be made compact and manufactured at low cost. be able to.
When the reaction vessel has a rib extending from one end side to the other end side on the inner wall surface, the spherical semiconductor strikes the rib and is pushed up and reacted with the rotation of the reaction vessel. Since it is spread | dispersed in the space part in a container, reaction becomes uniform in the whole surface of a semiconductor.

In the second preferred embodiment of the present invention, the impurities in the processing gas are diffused on the surface of the spherical semiconductor in the cylindrical reaction vessel having the inlet for introducing the processing gas and the outlet for discharging the gas. The reaction vessel is formed on the inner wall surface from one end side to the other end side, and protrudes toward the inside of the reaction vessel. At least two ribs, and the first rib is positioned on the other end side so that the other end side is positioned closer to the rotation direction of the reaction vessel than the one end side. Each rib is provided so that the longitudinal direction is inclined with respect to a line parallel to the axis of the reaction vessel so that the side is positioned on the near side in the rotation direction of the reaction vessel from the one end side. The axis is almost horizontal and the axis remains Characterized in that it has a rotating step of rotating the Ri.
The reaction vessel preferably has a plurality of first and second ribs and is alternately arranged on the inner wall surface of the reaction vessel, depending on the size.

According to the second embodiment, in the step of rotating the reaction vessel around its axial center, the spherical semiconductor flows and rotates, and the semiconductor on the inlet side of the processing gas by the first and second ribs. Will move to the outlet side, and the semiconductor on the outlet side will move to the inlet side. Further, as the reaction vessel is rotated, the semiconductor to be moved is dispersed into the space when it falls from the rib, so that the individual semiconductors are also temporarily separated. As a result, the degree of contact with the processing gas does not differ locally on the surface of the semiconductor. Therefore, the same effect can be obtained by swinging and rotating the reaction vessel.
In this embodiment, in addition to the first and second ribs, for example, a rib parallel to the axis of the reaction vessel may be provided. With this rib, the semiconductor is dispersed into the space in the reaction container as the reaction container rotates. In order to make the semiconductor distribution uniform in the reaction vessel, it is preferable that the same number of first ribs and second ribs are alternately arranged one by one.

  In a preferred third embodiment of the present invention, a cylindrical reaction vessel having an introduction port for introducing a processing gas and an exhaust port for discharging the gas is rotated around its axis, thereby allowing the inside of the reaction vessel to be rotated. A manufacturing method of a spherical semiconductor element, in which a diffusion layer is formed by diffusing impurities in a processing gas on the surface of a spherical semiconductor contained in the reactor, wherein one end portion of the reaction vessel is higher than the other end portion. The inner wall surface is provided so that it extends from one end side to the other end side and the other end side is located on the rotation direction side of the reaction vessel, and the reaction It has at least one rib protruding toward the inside of the vessel, and when the inclination angle of the reaction vessel is θ1, and the angle between the longitudinal direction of the rib and the line parallel to the axis of the reaction vessel is θ2, θ1 <Θ2 And butterflies.

  According to the third embodiment, the spherical semiconductor in the reaction vessel gathers on the lower side of the reaction vessel due to its gravity. The semiconductor is pushed up by the rib as the reaction vessel rotates, and further flows on the inclined rib and moves to the upper side of the reaction vessel. The semiconductors that move in this way are scattered into the space when falling from the ribs, so that the individual semiconductors are also temporarily separated. As a result, the degree of contact with the processing gas does not differ locally on the surface of the semiconductor. Therefore, the same effect can be obtained by swinging and rotating the reaction vessel.

  A preferred semiconductor device manufacturing apparatus for carrying out the method of the third embodiment includes an inclined plate pivotally supported on a base and capable of adjusting an inclination angle, and a heating block fixed to the inclined plate and provided with heating means inside. A cylindrical reaction vessel inserted into the heating block; a support connected to the reaction vessel and extending out of the heating block through the opening of the heating block; and the reaction vessel around its axis A rotation drive unit that rotates the gas, a processing gas supply device that supplies a processing gas to the reaction vessel, and a gas discharge device that discharges the gas from the reaction vessel. At least one that extends from the end side of the reaction vessel to the other end side and that the other end portion side is located on the rotation direction side of the reaction vessel and projects toward the inside of the reaction vessel The inclined plate has a rib, and when the reaction vessel rotates, the inclination angle is adjusted so that one end of the reaction vessel is higher than the other end, and the inclination angle of the reaction vessel is θ1, When the angle between the longitudinal direction of the rib and the line parallel to the axis of the reaction vessel is θ2, θ1 <θ2.

  In this apparatus, the semiconductor can be moved back and forth of the reaction vessel and sprayed into the space in the reaction vessel simply by rotating the reaction vessel. Therefore, the configuration of the apparatus becomes simpler.

In each of the above embodiments, it is preferable to further include a vibration step for vibrating the reaction vessel in addition to the swinging step and / or the rotating step.
When the vibration is applied to the reaction vessel, a large number of gathered semiconductors move their individual positions, so that the degree of contact with the processing gas on the semiconductor surface becomes more uniform.
During the formation of the diffusion layer on the surface of the seed-shaped semiconductor, an adhesive component may adhere to the surface of the semiconductor. When an adhesive component adheres to the surface of the semiconductor, the semiconductors aggregate with each other or adhere to the inner wall surface of the reaction vessel. The above vibration process can suppress such inconvenience.

Hereinafter, a semiconductor device manufacturing apparatus applicable to a photoelectric conversion device according to the present invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 is a side view in which a part of a semiconductor device manufacturing apparatus according to an embodiment is cut away, and FIG. 2 is a schematic diagram showing an internal configuration of a heating block and a system of a flow of processing gas.

The base 10 is comprised by the housing | casing which has a shelf inside, and has fixed the frame 11 to the upper part. The frame 11 is provided with a pair of bearings 12 at both ends.
The swing plate 15 has a shaft 17 attached to the center of the lower portion thereof by a shaft mounting member 16, and the shaft 17 is supported by the bearing 12. A rotating plate 20 is attached to the motor 19 fixed on the shelf 18 of the base 10. On the other hand, the upper end of the arm 21 as a joint is engaged with the ear piece 22 at the rear portion of the swing plate 15, and the lower end of the arm 21 is pivotally attached to a position shifted from the center of the rotating plate 20. As a result, the swinging plate 15 performs a swinging motion in which the front portion and the rear portion of the swinging plate 15 reciprocate in the upside down direction alternately by the motor 19. The oscillating plate 15 performs an oscillating motion that is inclined up and down by 5 ° with respect to the horizontal position shown in the figure, for example.

  A heating block 23 is fixed on the rocking plate 15 in the center. The heating block 23 can be divided into an upper part and a lower part, and has a space part 24 for housing the quartz core tube 40 and a heater 27 as a heating means for heating the core tube. Similarly, the core tube 40 has a quartz inlet tube 41 and an outlet tube 42 integrally joined in the front and rear. The core tube 40 is set inside the heating block 23 in a state where the heating block 23 is divided vertically. The inlet tube 41 and the outlet tube 42 of the core tube 40 extend from the openings 25 and 26 provided before and after the heating block 23 to the outside of the heating block.

  As shown in FIG. 3, the inlet tube 41 of the core tube 40 is supported by a driven roller 32 and two drive rollers 33, and rotates as indicated by an arrow. The driven roller 32 and the drive roller 33 are attached to a support plate 30 on the swing plate 15 as shown in FIG. A driving motor 28 is provided on the swing plate 15, and the driving force of the rotating plate 29 of the motor 28 is transmitted to the driving roller 33 via a power transmission mechanism 31 such as a gear or a belt. The support plate 35 on the swing plate 15 is provided with three driven rollers (not shown) that rotatably support the outlet pipe 42.

  As described above, the core tube 40 can be rotated around the axis of the core tube 40 in the heating block 23 by the motor 28. The rotation speed can be adjusted in the range of 1 to 7 rpm. Further, since the swing plate 15 swings around the shaft 17 as a fulcrum, the core tube 40 also swings in the same manner. The rocking speed can be adjusted in the range of 1 to 8 times / minute by reciprocating motion. As shown in FIG. 4, the core tube 40 has four ribs 48 extending on the inner surface in the longitudinal direction of the tube. A cooling device 70 is provided on the oscillating plate 15 in order to cool the outlet pipe 42 heated by the exhaust gas from the core tube 40. The cooling mechanism will be described later.

Next, a gas supply / discharge system for supplying and discharging process gas to the core tube 40 will be described with reference to FIG.
The supply path of nitrogen gas connected to the nitrogen gas cylinder 51 branches into 51A and 51B, and the supply path of oxygen gas connected to the oxygen gas cylinder 50 merges with the supply path 51A of nitrogen gas and is connected to the inlet pipe 41 of the core tube 40. Connected to the connecting portion 55. In the middle of each supply path of oxygen gas and nitrogen gas, flow meters F1, F2 and F3 having valves having a flow rate adjusting function are provided.

The supply path 51B of nitrogen gas branches into 51B1 and 51B2, and 51B2 is immersed in POCl ₃ indicated by 53 in the container 52. A supply path of nitrogen gas containing POCl ₃ passing through the container 52 is branched into 53A and 53B, and 53A is connected to the connecting portion 55. 53B is a purge path 56 that leads to a separately provided collection device. The nitrogen gas supply path 51 </ b> B <b> 1 is connected to the nitrogen gas supply path via the container 52. V1 to V4 represent open / close valves.

  The inlet tube 41 and the outlet tube 42 of the core tube 40 are sealed with a rubber plug 44 that penetrates the pipe 45 and a rubber plug 46 that penetrates the pipe 47, respectively. The connecting portion 55 at the end of the gas supply path has a pipe joint that connects the pipe 45 in a rotatable and airtight manner. Therefore, the processing gas can be supplied to the rotating core tube 40 from the connection portion 55 via the pipe 45, and the gas is not leaked to the outside. On the other hand, on the outlet pipe 42 side, the large-diameter portion 63 of the discharge pipe 62 covers the end portion of the pipe 47. A pipe 64 is connected to the pipe 62. This pipe 64 is immersed in the water 61 accommodated in the collection container 60. The gas phase portion of the collection container 60 is connected to the blower 66 by a pipe 65. The pipe 62 is supported by a support 67 fixed on the swing plate 15, and has a flexible portion at the rear of the support portion, and the swing plate 15 swings by the flexible portion. Even so, the large diameter portion 63 is always kept in the positional relationship with the end portion of the pipe 47.

Next, the operation of this apparatus will be described.
A large number of spherical p-type semiconductors are placed in the furnace tube 40 and set in the heating block 23. When the control unit of the apparatus is in the reset state, the valve V2 is opened, and nitrogen gas from the cylinder 51 is supplied to the core tube 40 through the supply path 51A at a flow rate of 5.5 L / min by the control of the flow meter F3. Is done. At this time, the core tube is heated to 800 ° C. In the first step, with the valve V2 kept open, the heater is controlled to raise the temperature of the core tube, for example, at a heating rate of 5 ° C./min. 5 minutes before the core tube reaches 900 ° C., the oxygen gas supply passage is controlled by the flow meter F1 to supply oxygen gas from the cylinder 50 at a flow rate of 0.4 L / min.

When the temperature of the core tube reaches 900 ° C., the heater is controlled so as to be maintained at the same temperature, and in the second step, the valves V1 and V4 are opened, and V2 and V3 are closed. As a result, nitrogen gas containing 120 mg of phosphorus oxychloride POCl ₃ per liter is supplied to the reactor core tube at a flow rate of 0.77 L / min. Thus, phosphorus glass is generated by the reaction of POCl ₃ and oxygen gas in the furnace core tube, and phosphorus generated by the reaction of this phosphorus glass and Si diffuses into the surface layer of the spherical semiconductor. Immediately after continuing this diffusion process for 30 minutes, in the third step, the flow meter F1 connected to the oxygen cylinder is manually operated to shut off the supply of oxygen gas, and the valves V1 and V4 are closed and the valves 2 and V3 are closed. open. As a result, the carrier nitrogen gas is purged from the purge path 56, and the nitrogen gas is supplied to the core tube only through the supply path 51A.
While continuing this supply of nitrogen gas, the temperature of the core tube is lowered at a rate of temperature decrease of 2 ° C./min. When the temperature of the furnace core tube reaches 800 ° C., in the fourth step, the temperature is maintained for 60 minutes, and the semiconductor element is annealed. Then, it cools to 300 degreeC and collect | recovers the processed semiconductor element. Nitrogen gas is stopped when it is allowed to cool to 300 ° C.

The gas discharged from the core tube 40 flows from the pipe 46 into the large diameter portion 63 of the pipe 62 together with the outside air by the suction force of the blower 66. The exhaust gas is discharged from the blower 66 through the water in the collection container 60 to the outside via a solid adsorbent (not shown). Most of POCl ₃ and its decomposition products in the exhaust gas are collected in the water in the collection container 60, and the remainder is removed by the solid adsorbent.
Water is supplied from a water supply pipe 71 provided with an on-off valve 72 to the cooling unit 70 that cools the outlet pipe 42 of the core tube 40, and is discharged from the pipe 73.

The processing gas supply part described above is stored in the base 10. The portion of the pipe connected to the connecting portion 55 that becomes a gas supply port to the core tube 40 is flexible, and the connecting portion 55 can swing together with the swing plate 15.
The core tube 40 has, for example, a length of 160 mm (a straight portion is 100 mm, a curved portion at the entrance and exit is 30 mm each) and a diameter of 106 mm. It is joined to. About 100,000 spherical first semiconductors having a diameter of about 1.0 mm are accommodated in the core tube 40 to form a diffusion layer (second semiconductor layer).

As described above, the oscillation and rotation of the core tube are controlled along with the control of the temperature of the core tube 40 and the gas supplied to the core tube. That is, the motor 19 is driven to swing the swing plate 15 and the motor 28 is driven to rotate the core tube 40. Thus, the spherical first semiconductor housed in the reactor core tube flows and rotates in the longitudinal direction and the radial direction of the reactor core tube, and the semiconductor pushed up by the rib is located in the reaction vessel when the rib cannot support it. Drop into the space. Thereby, each spherical first semiconductor can uniformly contact the processing gas, and a uniform second semiconductor layer can be formed.
In the present embodiment, the swing plate 15 is pivotally supported at the center by the base and is swung in a seesaw manner. However, the front or rear portion of the swing plate is pivotally supported by the rear or The front part may swing.

Embodiment 2
A semiconductor device manufacturing apparatus according to the present embodiment is shown in FIG. In the present embodiment, a vibration device is employed instead of the core tube rotation device in the first embodiment. That is, supports 37 and 38 that support the inlet tube 41 and the outlet tube 42 of the core tube 40 are provided on the swing plate 15, and two vibrators 39 are attached to the lower surface of the swing plate. These vibrators 39 vibrate the rocking plate 15 to vibrate the core tube. The upper portions of the supports 37 and 38 are branched in a Y shape, and the branch pipes support the inlet pipe 41 and the outlet pipe 42 of the core tube 40. Other configurations are the same as those in the first embodiment.
The vibration device used here can be added to the manufacturing apparatus of Embodiment 1 and Embodiments 3 and 4 described later. As a result, the effect of vibration, that is, the degree of contact with the processing gas due to the vibration of individual semiconductors becomes more uniform, and aggregation due to adhesion of adhesive components and adhesion to the inner wall of the reaction vessel are suppressed. An effect can be obtained.

Embodiment 3
In this embodiment, only the core tube is rotated, but the spherical element in the core tube is moved from the inlet side to the outlet side and from the outlet side to the inlet side by the rib provided on the inner wall of the core tube. Can do.

A core tube 40A used in the present embodiment is shown in FIGS.
The core tube 40A has an inlet tube 41A and an outlet tube 42A. The core tube 40A has four ribs 48a1, 48a2, 48b1, and 48b2 on its inner wall surface that extend from the front portion to the rear portion and project toward the inside of the core tube. The ribs 48a1 and 48a2 are positioned so that the front side is positioned on the rotational direction side of the core tube from the rear side, and the ribs 48b1 and 48b2 are positioned on the near side in the rotational direction of the core tube from the rear side. Each rib is provided with its longitudinal direction inclined at an angle θa and θb with respect to a line L parallel to the axis of the core tube (θa = θb). The arrangement of these ribs in the core tube is such that the inclination directions of adjacent ribs are different. Here, the rotation direction of the core tube is indicated by an arrow y. The rib inclination angles θa and θb are preferably in the range of 3 to 7 degrees. When θa and θb are less than 3 degrees, the movement of the spherical semiconductor on the rib and moving from the front part to the rear part and from the rear part to the front part of the reaction vessel becomes insufficient. When θa and θb exceed 7 degrees, the speed at which the spherical semiconductor flows on the ribs is too high, and the rate of falling from the ribs before reaching the front part or the rear part increases.
The apparatus for rotating the core tube 40A and the apparatus for supplying and discharging the processing gas to and from the core tube are the same as those in the first embodiment. That is, the rocking plate 15 in the first embodiment is fixed substantially horizontally, and therefore a device for rocking the rocking plate is unnecessary.

When the core tube 40A is rotated in the direction of the arrow y in FIG. 6, among the spherical semiconductors in the tube 40A, the spherical semiconductor pushed up by the rib 48b1 as the tube rotates is inclined so that the rib 48b1 is lowered on the inlet side. Therefore, it moves to the entrance side as indicated by an arrow x2. On the other hand, the spherical semiconductor pushed up by the rib 48a1 moves to the outlet side as indicated by an arrow x1 because the rib 48a1 is inclined so that the outlet side is lowered. Similarly, the spherical semiconductor pushed up by the rib 48b2 moves to the inlet side, and the spherical semiconductor pushed up by the rib 48a2 moves to the outlet side. Here, if the ribs 48a1, 48a2, 48b1 and 48b2 are inclined so that their top surfaces are directed in the rotation direction as shown in FIG. Alternatively, it is possible to reduce the dropout of the spherical semiconductor moving in the x2 direction. The number of ribs is not limited to four, but is preferably an even number in which ribs having different inclinations in the longitudinal direction of the ribs are alternately arranged, such as two or six. This is because the movement of the spherical semiconductor to the inlet side and the outlet side can be made substantially uniform. However, it is not necessary to do so.
As described above, according to the present embodiment, the core tube is equivalent to rotating and swinging the core tube in the first embodiment only by rotating the core tube around the axis with the axis center being substantially horizontal. Actions and effects can be obtained.

  In each of the above embodiments, the core tube is used as a reaction vessel. However, a cylindrical reaction vessel set so as to be able to be taken in and out of the furnace core tube may be used, and the diffusion treatment may be performed on the spherical semiconductor in the vessel. In that case, a method of rotating the reactor tube by rotating the reactor core tube, and the reactor tube can be fixed in the heating block so that only the reactor vessel can be rotated.

Embodiment 4
The semiconductor device manufacturing apparatus of the present embodiment is shown in FIG. 9, and the reaction container is shown in FIGS.
The base 80 is the same as the base of the first embodiment, and a frame 81 is fixed at the upper center. The frame 81 has a pair of bearings 82 at both ends. The inclined plate 85 installed on the base 80 is attached with a shaft 87 by a shaft mounting member 86 at the center of the lower portion, and the shaft 87 is supported by a bearing 82. The front ear piece 88 of the inclined plate 85 is connected to a small jack 83 on the base 80 by a wire 84. By operating the jack 83, the inclination angle θ1 of the inclined plate 85 with respect to the upper surface of the horizontal base 80 can be adjusted.

  On the inclined plate 85, a heating block 89 is fixed at the center. The heating block 89 has openings 91 and 90 at the front and rear, respectively, and has a heater 92 as a heating means for heating the reaction vessel 100 inside. As shown in FIG. 10, the reaction vessel 100 has a bottomed cylindrical shape, and a quartz column 101 is similarly coupled to the outside of the bottom. Similarly, a quartz lid 102 is detachably coupled to the opening of the reaction vessel 100. A cylindrical quartz heat shield 103 is attached to the lid 102. The lid 102 has a cylindrical portion 104 at the center for connection to a movable portion 121 provided on the outer periphery of the distal end of the rotary joint 120 described later.

  The rotary joint 120 is a double rotary joint constituted by a double pipe, and the inner pipe is connected to the gas supply pipe 123 and the outer pipe is connected to the gas discharge pipe 124. A gas supply pipe 122 connected to the inner pipe is connected to the distal end portion of the rotary joint 120, and a gas discharge hole (not shown) is provided on the end face so as to surround the gas supply pipe 122. . The rotary joint 120 is fixed on the inclined plate 85 by a support member 115, the processing gas supply path shown in FIG. 2 is connected to the gas supply pipe 123, and the pipe shown in FIG. 62 and the downstream part are connected.

  The reaction vessel 100 accommodates the spherical first semiconductor in the interior thereof, and after the lid 102 is coupled, the portion of the column 101 is inserted into the opening 90 from the opening 91 side of the heating block 89. Next, the cylindrical portion 104 of the lid 102 is coupled to the distal end portion of the rotary joint 120. At this time, the tip of the gas supply pipe 122 of the rotary joint 120 enters the reaction vessel 100 from the hole 105 of the heat shield 103.

  The cylindrical portion 101 of the reaction vessel 100 is supported by a driven roller 113 and two drive rollers 114 and can rotate, similarly to the outlet tube 41 of the reactor core tube in the first embodiment. The driven roller 113 and the driving roller 114 are attached to the support plate 111 on the inclined plate 85. A driving motor 109 is provided on the inclined plate 85, and the driving force of the rotating plate 110 of the motor 109 is transmitted to the driving roller 114 via a power transmission mechanism 112 such as a gear or a belt. On the other hand, since the cylinder portion 104 of the lid 102 of the reaction vessel 100 is connected to the movable portion 121 of the rotary joint 120, the reaction vessel 100 can be rotated by the motor 109.

  Four ribs 108 a, 108 b, 108 c and 108 d made of quartz are joined to the inner wall surface of the reaction vessel 100. These ribs extend from the front side (the left side in FIG. 10) of the reaction vessel to the rear side and are provided so that the rear side is located on the rotation direction side of the reaction vessel and project toward the center of the reaction vessel. Yes. Here, θ1 <θ2 where θ1 is an angle inclined from the horizontal plane L1 of the reaction vessel 100 and θ2 is an angle between the longitudinal direction of the rib and a line L2 parallel to the axis of the reaction vessel. θ1 is preferably in the range of 3 to 7 degrees, and θ2 to θ1 is preferably in the range of 3 to 7 degrees. If θ1 is less than 3 degrees, the semiconductor does not move smoothly from the upper part to the lower part along the inner wall surface of the reaction vessel. If the angle exceeds 7 degrees, the movement is too fast to cause a movement such as colliding with the bottom of the reaction vessel, making it difficult to push the semiconductor onto the rib. On the other hand, when θ2−θ1 is less than 3 degrees, the movement of the spherical semiconductor flowing on the rib and moving from the rear portion to the front portion of the reaction vessel is not smoothly performed. If θ2−θ1 exceeds 7 degrees, the moving speed is too high, and the rate at which the semiconductor falls from the ribs before reaching the front portion increases.

  When the reaction container 100 is rotated in the direction of arrow y by driving the motor 109, the spherical semiconductor in the reaction container 100 is pushed up by one of the ribs 108a to 108d as the reaction container rotates. At this time, since the rib is inclined so that the rear side is on the rotation direction side of the reaction vessel from the front side, for example, the spherical semiconductor on the rib 108a is pushed upward with the rotation of the reaction vessel. Then, as shown by an arrow x in FIG. Thus, the spherical semiconductor falling from the rib to the front side of the reaction vessel moves to the rear side along the inner wall surface of the reaction vessel because the reaction vessel is inclined so that the rear portion is lower. Thus, the movement from the front part to the rear part along the inner wall surface of the reaction container, the movement to the front part side of the reaction container pushed up by the rib, and the middle part of the rib without being able to move to the front part side on the rib The spherical semiconductor in the reaction vessel such as dropping from the vessel is sufficiently agitated with the rotation of the reaction vessel and sufficiently in contact with the processing gas. Therefore, the semiconductor gas can sufficiently contact the reaction gas supplied from the tip of the gas supply pipe 122 into the reaction vessel, and each semiconductor can form a uniform second semiconductor layer on the surface.

  FIG. 12 is a cross-sectional view similar to FIG. 11 of the reaction vessel 100A in which the ribs 108a to 108d are attached such that the tops thereof are inclined in the rotational direction. In the example of FIG. 11, all the ribs are attached so as to face the center direction of the reaction vessel. On the other hand, in the example of FIG. 12, all the ribs are inclined in the rotation direction of the reaction vessel by an angle θ3 from a straight line passing through the central direction of the reaction vessel. In this way, the spherical semiconductor pushed up by the rib as the reaction vessel rotates is less likely to drop beyond the top of the rib, and the semiconductor can be more easily moved to the front side by the rib.

In the present embodiment, the reaction vessel 100 is constituted by a bottomed cylindrical body, and a double rotary joint 120 constituted by a double pipe is connected to the opening thereof. Since the opening of the reaction vessel is larger than that used in the first to third embodiments, it becomes easy to load a spherical semiconductor and to take out the obtained semiconductor element.
The gas supply and discharge methods using the reaction vessel and the dual rotary joint used here can also be applied to the reaction vessels (furnace core tubes) of the first to third embodiments. In particular, in an embodiment in which the reaction vessel is rocked, it is advantageous that one end of the reaction vessel is closed, because there is no diffusion of the spherical semiconductor to the outside.
In the first to third embodiments, a single rotary joint may be connected to both ends of the reaction vessel, the processing gas may be supplied from one rotary joint, and the gas may be discharged from the other rotary joint. it can.

Hereinafter, the present invention will be described in more detail with reference to examples thereof.
Example 1
The quartz furnace tube has a length of 160 mm and an inner diameter of 106 mm, and a prism having a height of 10 mm, a thickness of 5 mm, and a length of 120 mm is joined to the inner surface as shown in FIG.
About 100,000 spherical first semiconductors (p-type semiconductors) having a diameter of about 1.0 mm were accommodated in such a furnace core tube to form second semiconductor layers (n-type semiconductor layers).
The supply / discharge of the gas and the control of the temperature when the process gas is supplied to the core tube and the second semiconductor layer is formed on the surface of the first semiconductor will be described with reference to the operation of the gas supply / discharge system shown in FIG. It is the same as what was done.
In this example, the core tube was swung. The rocking cycle was 1 time / minute, and the rocking angle was 5 degrees up and down with respect to the horizontal state.

Example 2
The core tube was swung and rotated in parallel. The rotation speed was 4 rpm. The rest is the same as in the first embodiment.

Example 3
The core tube was swung and vibrated in parallel. The vibration was a frequency of 5 Hz and an amplitude of 1.5 mm. The rest is the same as in the first embodiment.

Example 4
Only the rotation at a rotation speed of 4 rpm was performed without swinging the core tube. The rest is the same as in the first embodiment.

Example 5
In the present embodiment, the core tube has a length of 160 mm and a diameter of 106 mm, and four ribs having a thickness of 5 mm, a height of 15 mm, and a length of 120 mm are joined to the inner surface as shown in FIGS. A furnace core tube was used.
The angle θa between the longitudinal direction of the ribs 48a1 and 48a2 and the line parallel to the axis of the core tube is 5 degrees, and the angle θb between the longitudinal direction of the ribs 48a1 and 48a2 and the line parallel to the axis of the core tube is 5 degrees. is there.
The core tube was only rotated at a rotational speed of 4 rpm. Other than the above, the second embodiment is the same as the first embodiment.

Example 6
The apparatus described in Embodiment 4 was used. The reaction vessel has a length of 160 mm and an inner diameter of 106 mm, and four ribs having a length of 120 mm, a thickness of 5 mm, and a height of 15 mm are provided on the inner surface at an inclination angle of θ2 = 10 degrees.
The reaction vessel was set at an inclination angle θ1 = 5 degrees and rotated at a rotation speed of 4 rpm. Other conditions are the same as those in the first embodiment.

Example 7
Example 6 was the same as Example 6 except that θ3 = 10 degrees so that the top of the rib was in the rotation direction of the reaction vessel.

<< Comparative Example 1 >>
Only vibration with a frequency of 5 Hz and an amplitude of 1.5 mm was performed. The rest is the same as in the first embodiment.

<< Comparative Example 2 >>
It remained stationary without moving the core tube. The rest is the same as in the first embodiment.

The spherical first semiconductor used in the above examples and comparative examples was produced as follows.
First, a p-type polycrystalline Si lump containing a very small amount of boron was supplied into a crucible and melted at 1450 ° C. in an inert gas atmosphere. The melt was dropped from a minute nozzle hole at the bottom of the crucible, and the droplet was cooled and solidified during natural fall. Thus, a polycrystalline or single crystal spherical p-type semiconductor was produced.

  The surface of the produced spherical p-type semiconductor was polished, and after removing about 50 μm of the surface layer by etching, it was subjected to the above diffusion treatment. By this diffusion treatment, an n-type semiconductor layer having a thickness of about 0.5 μm was formed as a second semiconductor layer on the surface of the p-type semiconductor.

  As described above, 20 samples were arbitrarily collected as evaluation samples from the spherical photoelectric conversion elements in which the second semiconductor layer was formed on the surface of the spherical first semiconductor according to each of the examples and comparative examples. By removing a part of the surface of each sample by grinding, an opening was formed in the second semiconductor layer to expose a part of the first semiconductor. This process is shown in FIGS. 13 (a) and (b). A part of the spherical first semiconductor 1 covered with the second semiconductor layer 2 is cut off, and the opening 3 of the second semiconductor layer is formed in the outer peripheral portion of the smooth cut surface, and the first semiconductor circle is formed inside thereof. The exposed portion 4 is formed.

  Next, an electrode was formed on the exposed portion of the spherical first semiconductor. As the electrode forming material, a glass frit type conductive paste in which Al powder and Ag powder were dispersed was used. This paste was applied to the circular exposed portion 4 of the first semiconductor, dried at about 100 ° C. for about 10 minutes, and then heat-treated at about 700 ° C. for 10 minutes to form the electrode 5 (FIG. 13C). )).

As described above, a spherical element having the electrode 5 formed on the exposed surface of the first semiconductor is loaded into a simple prober jig, and the electrical characteristics between the electrode 5 and the second semiconductor layer 2 are measured using a solar simulator. did. The incident light conditions of the solar simulator are AM-1.5 and 100 mW / cm ² . Table 1 shows the average value and standard deviation of each characteristic.

As is clear from Table 1, the device characteristics according to Examples 1 to 5 have higher average values and smaller standard deviations than Comparative Example 2. This indicates that, when a large number of spherical elements are diffused according to the present invention, the dispersion between the elements in the diffusion state is small and a uniform diffusion layer is formed on each element.
It can be seen that it is effective to merely swing the core tube (Example 1) and only to rotate (Example 4), and the effect of the swing is relatively large. It can be seen that when rocking and rotation are performed in parallel (Example 2), the rocking and rotation are even better than the rocking and rotation alone, and the synergistic effect of rocking and rotation is remarkable.

In Example 5 in which a special rib is provided on the inner surface and only rotation is performed, the same characteristics as in Example 2 in which rocking and rotation are performed are obtained, and it can be seen that the special rib provides the same effect as the swinging. Comparative example 1 with only vibration has no significant effect compared with comparative example 2 in a stationary state. However, when vibration is applied to the rocking (Example 3), a better result than rocking alone is obtained, and it can be seen that a synergistic effect of rocking and vibration can be obtained.
Examples 6 and 7 showed a high characteristic value with little variation and a level comparable to Examples 2 and 5. In comparison between Examples 6 and 7, Example 7 was superior.

  According to the present invention, a spherical semiconductor element having a constant quality can be manufactured. Among the semiconductor elements according to the present invention, the photoelectric conversion element is particularly useful for a solar cell device.

It is the side view which notched the principal part of the apparatus in one embodiment of this invention. 1 is a schematic diagram showing a structure of a core tube of the apparatus and a supply / discharge system of processing gas. It is a front view which shows the rotation part of the pipe | tube in the inlet pipe of a core tube. It is a cross-sectional view of a core tube. It is the side view which notched the principal part of the apparatus in other embodiment of this invention. It is a longitudinal cross-sectional view of the core tube in other embodiment of this invention. It is the VII-VII sectional view taken on the line of FIG. It is the VIII-VIII sectional view taken on the line of FIG. It is the side view which notched the principal part of the apparatus in other embodiment of this invention. It is a longitudinal cross-sectional view of the reaction container of FIG. It is the XI-XI sectional view taken on the line of FIG. It is sectional drawing of the part corresponded in FIG. 11 of the reaction container in other embodiment of this invention. It is sectional drawing which shows the manufacturing process of the photoelectric conversion element in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st semiconductor 2 2nd semiconductor (diffusion layer)
DESCRIPTION OF SYMBOLS 10 Base 12 Bearing 15 Oscillating plate 19, 28 Motor 23 Heating block 25, 26 Opening part 27 Heater 32 Followed roller 33 Drive roller 39 Vibrator 40, 40A Core tube (reaction vessel)
41, 41A Inlet pipe 42, 42A Outlet pipe 48, 48a, 48b, 48c, 48d Rib 50 Oxygen gas cylinder 51 Nitrogen gas cylinder 53 Phosphorus oxychloride 55 Connection section having pipe joint 61 Water 66 Blower

Claims (13)

  A method for manufacturing a spherical semiconductor element, wherein a diffusion layer is formed by diffusing impurities in a processing gas on the surface of a spherical semiconductor in a cylindrical reaction vessel having an introduction port for introducing a processing gas and an exhaust port for discharging the gas A method for producing a spherical semiconductor element, comprising the step of causing the spherical semiconductor to flow and rotate in the reaction container by swinging or rotating the reaction container.   A method for manufacturing a spherical semiconductor element, wherein a diffusion layer is formed by diffusing impurities in a processing gas on the surface of a spherical semiconductor in a cylindrical reaction vessel having an introduction port for introducing a processing gas and an exhaust port for discharging the gas A method for manufacturing a spherical semiconductor element, comprising: a swinging step in which at least one of the front and rear portions of the reaction vessel reciprocates in the vertical direction.   The method for manufacturing a spherical semiconductor element according to claim 2, further comprising a rotating step of rotating the reaction vessel around its axis.   4. The method for manufacturing a spherical semiconductor element according to claim 3, wherein the swinging step and the rotating step are performed in parallel.   The spherical semiconductor according to claim 3 or 4, wherein the reaction vessel has at least one rib on its inner wall surface extending from one end side to the other end side and projecting toward the inside of the reaction vessel. Device manufacturing method.   A method for manufacturing a spherical semiconductor element, wherein a diffusion layer is formed by diffusing impurities in a processing gas on the surface of a spherical semiconductor in a cylindrical reaction vessel having an introduction port for introducing a processing gas and an exhaust port for discharging the gas The reaction container has at least two ribs extending from one end side to the other end side and projecting toward the inside of the reaction container on the inner wall surface, The second rib has the other end side in the rotation direction of the reaction vessel from the one end side so that the other end side is positioned on the rotation direction side of the reaction vessel from the one end portion side. Each rib is provided so that the longitudinal direction thereof is inclined with respect to a line parallel to the axis of the reaction vessel, and the reaction vessel is placed around the axis with its axis substantially horizontal. Characterized in that it has a rotation process to rotate Method of manufacturing a spherical semiconductor element that.   The method for producing a spherical semiconductor element according to claim 6, wherein there are a plurality of first and second ribs, and each one is arranged alternately on the inner wall surface of the reaction vessel.   A cylindrical reaction vessel having an inlet for introducing a processing gas and an exhaust port for discharging the gas is rotated around its axial center, so that the surface of the spherical semiconductor contained in the reaction vessel is placed on the surface of the processing gas. A method of manufacturing a spherical semiconductor element in which a diffusion layer is formed by diffusing impurities, wherein the reaction vessel is inclined so that one end thereof is higher than the other end, And at least one rib which extends from one end side to the other end side and is provided so that the other end side is positioned on the rotation direction side of the reaction vessel and protrudes toward the inside of the reaction vessel Of the spherical semiconductor element, wherein θ1 <θ2 where θ1 is an angle of inclination of the reaction vessel and θ2 is an angle between the longitudinal direction of the rib and a line parallel to the axis of the reaction vessel. Production method.   The method for manufacturing a spherical semiconductor element according to claim 6 or 8, wherein a top portion of the rib is inclined toward a rotation direction of the reaction vessel.   The manufacturing method of the spherical semiconductor element in any one of Claims 1-9 which further has the vibration process which vibrates the said reaction container.   A swinging plate pivotally supported on a base, a swinging plate driving unit connected to the front or rear of the swinging plate and reciprocating up and down, and fixed to the swinging plate A heating block provided with heating means, a cylindrical reaction vessel located in the heating block, a support connected to the reaction vessel and extending through the opening of the heating block, and the reaction vessel A spherical drive characterized in that it comprises a rotation drive unit that rotates the shaft around its axis, a processing gas supply device that supplies processing gas to the reaction vessel, and a gas discharge device that discharges gas from the reaction vessel. Semiconductor device manufacturing equipment.   The apparatus for manufacturing a spherical semiconductor element according to claim 11, wherein the reaction vessel has a rib extending from one end side to the other end side on the inner wall surface. An inclined plate pivotally supported on a base and capable of adjusting an inclination angle, a heating block fixed to the inclined plate and provided with heating means inside, a cylindrical reaction vessel inserted into the heating block, connected to the reaction vessel A support portion extending out of the heating block through the opening of the heating block, a rotation driving portion for rotating the reaction vessel around its axis, and a processing gas supply device for supplying a processing gas to the reaction vessel And a gas discharge device for discharging gas from the reaction vessel, the reaction vessel extending on the inner wall surface from one end side to the other end side, and the other end side being the reaction vessel And has at least one rib protruding toward the inside of the reaction vessel, and the inclined plate is rotated when one of the reaction vessels is rotated. When the inclination angle is adjusted so that the portion is higher than the other end, the inclination angle of the reaction vessel is θ1, and the angle between the longitudinal direction of the rib and the line parallel to the axis of the reaction vessel is θ2, An apparatus for manufacturing a spherical semiconductor element, wherein θ1 <θ2.

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