JP3995132B2 - Solar cell, semiconductor device, method for manufacturing solar cell, and method for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solar cell, a semiconductor device, a method for manufacturing a solar cell, and a method for manufacturing a semiconductor device, and particularly relates to a solar cell using a spherical cell, a semiconductor device, a method for manufacturing a solar cell, and a method for manufacturing a semiconductor device.
[0002]
[Prior art]
An internal electric field is generated at the pn junction portion of the semiconductor. When light is applied to the semiconductor to generate an electron-hole pair, the generated electron and hole are separated by the internal electric field, and the electron is positively connected to the n side. The holes are collected on the p side, and when a load is connected to the outside, a current flows from the p side to the n side. Utilizing this effect, solar cells are being put to practical use as elements that convert light energy into electrical energy.
[0003]
In recent years, a technique for manufacturing a semiconductor element by forming a circuit pattern on a spherical semiconductor (Ball Semiconductor) having a diameter of 1 mm or less such as single crystal or polycrystalline silicon has been developed.
[0004]
As one of them, a method for manufacturing a solar array in which a large number of semiconductor particles are connected using aluminum foil has been proposed (Japanese Patent Laid-Open No. 6-13633). In this method, as shown in FIG. 10, semiconductor particles 207 having an n-type skin portion and a p-type interior are arranged so as to protrude from both sides of the aluminum foil 201 in the opening of the aluminum foil, and the skin portion 209 on one side is removed. Then, the insulating layer 221 is formed. Next, a part of the p-type interior 211 and the insulating layer 221 thereon are removed, and the second aluminum foil 219 is bonded to the removed region 217. The flat region 217 provides good ohmic contact with the second aluminum foil 219 serving as a conductive portion.
[0005]
[Problems to be solved by the invention]
However, in such a method, there is a limit to the high-density arrangement, and positioning on the aluminum foil is difficult, and particularly when a large number of semiconductor particles are mounted, workability is poor. It is difficult to obtain a regular arrangement because it is easily affected by variations in diameter and shape.
Moreover, there existed a problem in the adhesive strength of a board | substrate (aluminum foil) and a semiconductor particle, and stability of a junction part.
In addition, for the formation of the electrodes, contact terminals to both the first conductivity type skin and the second conductivity type are necessary. However, reliable contact terminals can be formed without reducing the light receiving area. Therefore, there is a problem that the light receiving efficiency deteriorates.
[0006]
Furthermore, in order to perform stable mounting, it is necessary to improve the adhesion between the semiconductor particles and the substrate. Therefore, when the adhesion area is increased, there is a problem that the light receiving area decreases.
[0007]
The present invention has been made in view of the above problems, and is a solar cell that is stable and has high light receiving efficiency, can easily obtain a regular arrangement, and has high adhesion strength between a substrate and semiconductor particles. An object of the present invention is to provide a semiconductor device, a method for manufacturing a solar cell, and a method for manufacturing a semiconductor device.
[0008]
[Means for Solving the Problems]
The first solar cell of the present invention has a substrate having a concave portion in which at least a part of a side wall constitutes a reflective surface, and is opposite to the reflective surface in the concave portion so as to receive reflected light from the reflective surface. And a spherical cell that is fixed in contact with the side wall on the side and that is partially cut away on the side of the concave wall surface facing the reflecting surface of the concave .
According to such a configuration, by fixing the spherical cell in the recess, the adhesion strength between the substrate and the spherical cell is increased and is chemically stable. Further, since the inner wall of the recess is used as a reflection surface, and incident light is efficiently guided to the light receiving surface of the solar cell, a highly efficient and highly reliable solar cell can be obtained.
[0009]
The second of the present invention, in the solar cell according to claim 1, the recess of the substrate are arranged side by side in plurality in parallel to each of the recesses, a plurality of the spherical cells along a longitudinal direction one column It is arranged in order.
According to such a configuration, a regular arrangement can be easily obtained even if the spherical cells have some variation in diameter and shape.
[0010]
The third of the present invention is the solar cell according to claim 1, having a groove extending in the recess longitudinal direction on the bottom surface of each of the recesses, a plurality to engage said spherical cells into the groove the spherical cells is characterized in that it is arranged in a row.
According to such a configuration, even if there is a slight variation in the diameter and shape of the spherical cells, a regular arrangement can be easily obtained, and the adhesion strength between the substrate and the spherical cells can be increased by engaging the spherical cells with the grooves. It becomes even stronger.
[0011]
According to a fourth aspect of the present invention, in the solar cell according to any one of the first to third aspects, the concave portion is filled with a light transmissive resin.
According to such a configuration, a stronger and more stable connection is possible, and a significant improvement in life can be achieved.
[0012]
A fifth semiconductor device of the present invention has two rows of grooves formed in a substrate having recesses on the bottom surface of the recesses along the longitudinal direction so as to have a predetermined distance from each other. A plurality of spherical cells are arranged in two rows so as to engage with the grooves.
According to such a configuration, even if the spherical cells have a slight variation in diameter and shape, a regular arrangement can be easily obtained, and by combining the spherical cells with the two rows of grooves in the recesses, The adhesion strength of the spherical cell is increased and it is chemically stable.
[0013]
According to a sixth method of manufacturing a solar cell of the present invention, a step of preparing a substrate having a concave portion in which at least a part of a side wall constitutes a reflecting surface, and a second conductive semiconductor on the surface of the first conductive semiconductor layer Fixing a plurality of spherical cells formed with layers to the recesses of the substrate in contact with the side wall opposite to the reflecting surface in the recesses and arranged in a line along the longitudinal direction; A step of cutting a part of the spherical cell on the concave wall surface facing the reflecting surface of the concave, and the second conductive exposed at the cut pattern of the substrate or the conductive pattern provided on the substrate and the spherical cell. Electrically connecting a type semiconductor layer, a step of forming a contact on the first conductive type semiconductor layer of the spherical cell, an electrode formed on the substrate, and the first conductive type semiconductor layer Electrically connecting the contacts; Characterized in that it contains.
According to this method, a regular array can be easily formed even if the spherical cells have a slight variation in diameter and shape. Moreover, the adhesion strength between the substrate and the spherical cell is strong, and a chemically stable solar cell can be formed. In addition, since the inner wall of the recess is used as a reflection surface, and incident light is efficiently guided to the light receiving surface of the solar cell, a highly efficient and reliable solar cell can be formed.
[0014]
The seventh method for manufacturing a solar cell according to the present invention has a plurality of recesses in which at least a part of the side wall constitutes a reflection surface, and a groove extending in the recess longitudinal direction on the bottom surface of each of the plurality of recesses And a plurality of spherical cells each having a second conductivity type semiconductor layer formed on the surface of the first conductivity type semiconductor layer, and each of the recesses in each of the recesses is engaged with the groove. A step of adhering to the side wall opposite to the reflection surface and arranging in a line along the longitudinal direction, and a step of cutting off a part of the spherical cell on the concave wall surface facing the reflection surface of the concave portion; Electrically connecting the substrate or the conductive pattern provided on the substrate and the second conductive semiconductor layer exposed in the cut portion of the spherical cell; and the first conductive semiconductor layer of the spherical cell Forming a contact on the substrate and an electrode formed on the substrate Characterized in that it comprises the step of electrically connecting the contacts of the first conductivity type semiconductor layer.
According to this method, a regular array can be easily formed even if the spherical cells have a slight variation in diameter and shape. Moreover, the adhesion strength between the substrate and the spherical cell is further increased, and a chemically stable solar cell can be formed. In addition, since the inner wall of the recess is used as a reflection surface, and incident light is efficiently guided to the light receiving surface of the solar cell, a highly efficient and reliable solar cell can be formed.
[0015]
According to an eighth aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: a plurality of recesses each having at least a part of a side wall forming a reflective surface; And a step of preparing a substrate having two rows of grooves formed so as to have a distance between the first conductive type semiconductor layer and a spherical cell having a second conductive type semiconductor layer formed on the surface of the first conductive type semiconductor layer. as a plurality of spherical cells into engagement are arranged in two rows, fixed to a step of electrically connecting to the conductive pattern provided on a substrate or on a substrate, a first conductivity type of the spherical cells The method includes a step of forming a contact in a semiconductor layer, and a step of electrically connecting an electrode formed on the substrate and a contact of the first conductivity type semiconductor layer.
According to this method, a regular array can be easily formed even if the spherical cells have a slight variation in diameter and shape. In addition, it is possible to form a semiconductor device that has a stronger adhesion strength between the substrate and the spherical cell and is chemically stable.
[0016]
Ninth present invention provides a method of manufacturing a semiconductor device according to claim 8, in the step of forming a contact to the first conductive semiconductor layer of the spherical cells, so as to remove a portion of the spherical body cells ground, and forming a contact by forming a bonding pad on the first conductive type semiconductor layer of the grinding surface of the spherical body cells.
According to this method, the connection between the first conductive semiconductor layer of the spherical cell and the electrode can be easily formed by wire bonding or the like.
[0017]
According to a tenth aspect of the present invention, in the semiconductor device manufacturing method according to the ninth aspect, the ground surface of the spherical cell and the convex portion of the substrate are formed at the same height.
According to this method, when the ground surface of the spherical cell and the convex portion of the substrate are formed at the same height, the insulating film can be easily attached when the substrate is conductive. Further, the spherical cell and the convex portion of the substrate can be ground in the same process.
[0018]
According to an eleventh aspect of the present invention, in the method for manufacturing a solar cell according to claim 6 or 7, the cut surface of the cut portion of the spherical cell and the convex portion of the substrate are formed at the same height. Features.
According to this method, when the cut surface of the spherical cell and the convex portion of the substrate are formed at the same height, the insulating film can be easily pasted when the substrate is conductive. Further, the spherical cell and the convex portion of the substrate can be ground in the same process.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a solar cell, a semiconductor device, a method for manufacturing a solar cell, and a method for manufacturing a semiconductor device according to the present invention will be described in detail with reference to the drawings.
[0020]
(First embodiment)
In the solar cell according to the first embodiment, as shown in a perspective view of a main part in FIG. 1, a concave portion 17a is formed on the surface of the insulating substrate 17 so that the inner wall forms a reflecting surface, and the longitudinal direction A plurality of spherical cells are arranged in a line along and mounted.
[0021]
As shown in a schematic cross-sectional view in FIG. 2, a spherical cell 10 having an n-type semiconductor layer 12 (second conductivity type semiconductor layer) that forms a pn junction with a p-type semiconductor layer 11 (first conductivity type semiconductor layer) includes: The conductive paste 16 is fixed and electrically connected to the concave portion 17a of the insulating substrate 17 on which a conductor pattern (not shown) to be an n-type electrode is formed. The recess 17a of the insulating resin substrate 17 has a reflection surface 17c on one of the wall surfaces surrounding the recess. The reflection surface 17c is formed at an inclination angle such that the reflected light is efficiently reflected from the spherical cell 10.
[0022]
The sphere cell 10 has a ground surface 10a in which a part of the sphere is cut, and an insulating resin for electrically insulating the p-type semiconductor layer 11 and the n-type semiconductor layer 12 on the ground surface 10a. The conductive resin 13 for connecting the p-type semiconductor layer 11 and the p-type electrode 15 provided on the convex portion 17b of the insulating resin substrate 17 is formed thereon. Yes.
[0023]
Next, an example of a specific manufacturing method will be described below.
First, an example of a method for forming the spherical cell 10 used in the present invention will be described.
A p-type polycrystalline silicon particle having a diameter of 1 mm is dropped while being heated in a vacuum to form a p-type polycrystalline silicon sphere (p-type semiconductor layer) 11 having good crystallinity, and silane containing phosphine is formed on the surface. An n-type polycrystalline silicon layer (n-type semiconductor layer) 12 is formed by a CVD method using the above mixed gas. Here, in the CVD process, a thin film is formed by supplying and discharging a gas heated to a desired reaction temperature while carrying a silicon sphere in a thin tube.
[0024]
In this step, the p-type polycrystalline silicon grains are spheroidized while being heated and dropped in vacuum to form a p-type polycrystalline silicon sphere (p-type semiconductor layer) 11 and a desired gas in the course of dropping. It is also possible to form an n-type polycrystalline silicon layer (n-type semiconductor layer) 12 by contacting them.
[0025]
A thin film may be deposited outside the n-type polycrystalline silicon layer (n-type semiconductor layer) 12 by a transparent conductive film (for example, ITO) sputtering method or the like.
Further, an antireflection film may be formed outside the transparent conductive film by sputtering or the like.
[0026]
Next, the manufacturing method of the solar cell using the above-mentioned spherical cell 10 is demonstrated using FIG. FIG. 3 is a schematic cross-sectional view of each step of manufacturing the solar cell according to the present embodiment.
[0027]
As shown in FIG. 3A, an uneven insulating resin substrate 17 (for example, polyprosterene, acrylic, etc.) is prepared. The recess 17a of the insulating resin substrate 17 has a reflection surface 17c on one of the wall surfaces surrounding the recess. A p-type electrode 15 of a solar cell is formed on the convex portion 17b. The reflection surface 17c is formed at an angle set so that the reflected light is efficiently reflected by the spherical cell 10. Moreover, it is preferable to coat the reflective surface 17c with a metal thin film having a high reflectance.
[0028]
Next, as shown in FIG. 3B, the spherical cell 10 in which the n-type semiconductor layer 12 is formed on the surface of the p-type semiconductor layer 11 is replaced with a conductive paste 16 (for example, Ag paste). The insulating resin substrate 17 having unevenness is fixed so as to be in contact with the wall surface facing the reflecting surface 17c in the concave portion 17a, and is regularly arranged and mounted.
[0029]
Further, the concave portion 17a may be filled with a light transmissive resin or the like. The light-transmitting resin selected here needs to have a refractive index that can efficiently guide the reflected light from the reflecting surface 17c formed on the inner wall of the concave portion 17a to the light receiving region of the spherical cell 10. is there. As a result, a stronger and more stable connection is possible, and the life can be significantly improved.
[0030]
Next, as shown in FIG. 3 (c), in order to expose the p-type semiconductor layer 11 by mechanical polishing, grinding is performed so as to remove a part of the wall surface facing the reflecting surface 17c of the spherical cell 10. .
[0031]
Next, as shown in FIG. 3D, an insulating resin 14 (for example, for electrically insulating the p-type semiconductor layer 11 and the n-type semiconductor layer 12 on the ground surface of the spherical cell 10). Apply epoxy resin, silicone resin, etc.
[0032]
Next, as shown in FIG. 3E, the p-type semiconductor layers 11 exposed by grinding or the p-type electrodes provided on the convex portions 17b of the insulating resin substrate 17 are connected to each other. Resin 13 is applied to the ground surface. Alternatively, instead of the conductive resin 13, a conductive paste, metal, metal clip, wire bond, ultrafine particle, or the like may be used.
[0033]
(Second Embodiment)
In the solar cell according to the second embodiment, as shown in a perspective view of a main part in FIG. 4, a concave portion 27a is formed on the surface of the metal substrate 27 so that the inner wall forms a reflecting surface, and the concave portion 27a is further formed. A plurality of spherical cells 10 are arranged in a line and mounted so that a groove 28 is formed on the bottom surface of the substrate and the spherical cells are aligned with the groove 28.
[0034]
As shown in a schematic cross-sectional view in FIG. 5, a spherical cell 10 having a p-type semiconductor layer 11 (first conductivity type semiconductor layer) and an n-type semiconductor layer 12 (second conductivity type semiconductor layer) forming a pn junction. Is fixed to and electrically connected to the recess 27a of the metal substrate 27 to be an n-type electrode by the conductive paste 26 so as to be aligned with the groove 28 in the recess 27a. The concave portion 27a of the metal substrate 27 has a reflective surface 27c on one of the wall surfaces surrounding the concave portion. The reflection surface 27c is formed at an inclination angle such that the reflected light is efficiently reflected from the spherical cell 10.
[0035]
The spherical cell 10 has a ground surface 10a in which a part of the spherical body is cut, and an insulating film 24 for electrically insulating the p-type semiconductor layer 11 and the n-type semiconductor layer 12 on the ground surface 10a. However, the p-type electrode 25 of the solar cell is formed on the insulating film 24. The p-type electrode 25 of the solar cell is formed on the ground surface 10a and the convex portion 27b.
[0036]
A heavily doped polycrystalline silicon layer 11b is formed on the p-type semiconductor layer of the ground surface 10a, and a bonding pad 23 is formed on the polycrystalline silicon layer 11b. The electrode 25 is connected by a bonding wire 29.
[0037]
Next, a method for manufacturing the solar cell according to the present embodiment will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of each step of manufacturing the solar cell according to the present embodiment.
The method for forming the spherical cell 10 is as described in the first embodiment.
[0038]
First, as shown in FIG. 6A, a groove 28 is formed in advance in a concave portion 27a of a metal substrate 27 having irregularities (for example, Al, Cu, SUS, etc.). The recess 27a of the metal substrate 27 has a reflection surface 27c on the wall surface surrounding the recess. The reflection surface 27c is formed at an angle set so that the reflected light is efficiently reflected by the spherical cell 10. The reflective surface 27c may be coated with a metal thin film having a higher reflectance than the metal substrate 27.
[0039]
Next, as shown in FIG. 6B, the spherical cell 10 is fixed so as to be engaged with the groove 28 in the concave portion 27a of the metal substrate 27, and the reflection in the concave portion 27a of the metal substrate 27 having unevenness. It is fixed so as to be in contact with the wall surface facing the surface 27c, and is regularly arranged and mounted.
[0040]
Further, the concave portion 27a may be filled with a light transmissive resin or the like. The light-transmitting resin selected here needs to have a refractive index that can efficiently guide the reflected light from the reflecting surface 27c formed on the inner wall of the recess 27a to the light receiving region of the spherical cell 10. is there. As a result, a stronger and more stable connection is possible, and the life can be significantly improved.
[0041]
Next, as shown in FIG. 6C, a part of the spherical cell 10 on the wall surface facing the reflecting surface 27c is removed by mechanical polishing so that the p-type semiconductor layer 11 is exposed. The polycrystalline silicon layer 11b which is heavily doped is formed by selective vapor deposition on the ground surface 10a of the p-type semiconductor layer, and the bonding pad 23 is provided thereon.
[0042]
Next, as shown in FIG. 6D, the protrusion 27 b of the metal substrate 27, the p-type semiconductor layer 11 on the ground surface of the spherical cell 10, and the n-type semiconductor layer 12 are electrically insulated. An insulating film 24 is attached.
[0043]
Next, as shown in FIG. 6E, a p-type electrode 25 of a solar cell is formed on the insulating film 24 by a conductive film or a plating method.
[0044]
Next, as shown in FIG. 6F, the p-type electrode 25 and the bonding pad 23 are connected by the bonding wire 29.
Alternatively, instead of the bonding wire 29, a conductive paste, metal, metal clip, wire bond, ultrafine particle, or the like may be used.
[0045]
(Third embodiment)
In the semiconductor device according to the third embodiment, as shown in a perspective view of a main part in FIG. 7, spherical cells 10 are arranged in two rows in each recess 37a of each recess 37a of a metal substrate 37 having a plurality of recesses and projections. -It is characterized by being mounted.
[0046]
As shown in the schematic cross-sectional view of FIG. 8, a spherical cell 10 having an n-type semiconductor layer 12 (second conductivity type semiconductor layer) forming a pn junction with a p-type semiconductor layer 11 (first conductivity type semiconductor layer). Are fixed to the recesses 37a of the metal substrate 37 by the conductive paste 36 so as to be aligned with the two rows of grooves 38a, 38b in the recesses 37a.
[0047]
The spherical cell 10 has a ground surface 10a in which a part of the spherical body is cut, and an insulating film 34 for electrically insulating the p-type semiconductor layer 11 and the n-type semiconductor layer 12 on the ground surface 10a. However, the p-type electrode 35 of the semiconductor device is formed on the insulating film 34. The p-type electrode 35 of the semiconductor device is formed on the ground surface 10a and the projection 37b.
[0048]
A heavily doped polycrystalline silicon layer 11b is formed on the p-type semiconductor layer of the ground surface 10a, and a bonding pad 33 is formed on the polycrystalline silicon layer 11b. The electrode 35 is connected by a bonding wire 33a.
[0049]
Next, a method for manufacturing the semiconductor device according to the present embodiment will be described with reference to FIGS. FIG. 9 is a schematic cross-sectional view of each step of manufacturing the semiconductor device according to the present embodiment.
The method for forming the spherical cell 10 is as described in the first embodiment.
[0050]
First, as shown in FIG. 9A, an uneven metal substrate 37 (for example, Al, Cu, SUS, etc.) is used. Two rows of grooves 38a and 38b are formed in the recess 37a.
[0051]
First, as shown in FIG. 9B, the spherical cells 10 are fixed so as to be engaged in the grooves 38a and 38b, respectively, and regularly arranged so as to be in contact with the wall surfaces on both sides of the metal substrate 37. To do.
The spherical cells 10 in each row are arranged so as not to contact as shown in the figure, but may be arranged so as to contact each other.
[0052]
Next, as shown in FIG. 9C, the p-type semiconductor layer 11 is exposed by mechanical polishing. As shown in the figure, grinding is performed so as to remove a part of the spherical cell 10, and a highly doped polycrystalline silicon layer 11b is formed on the ground surface 10a of the p-type semiconductor layer by selective vapor deposition, A bonding pad 33 is provided thereon.
[0053]
Next, as shown in FIG. 9 (d), the projection 37b of the metal substrate 37, the p-type semiconductor layer 11 on the ground surface of the two rows of spherical cells 10 sandwiching the projection 37b, and the n-type semiconductor An insulating film 34 for electrically insulating the layer 12 is attached.
[0054]
Next, as shown in FIG. 9E, a p-type electrode 35 is formed on the insulating film 34 by a conductive film or a plating method.
[0055]
Next, as shown in FIG. 9 (f), the p-type electrode 35 and the bonding pads 33 of the two rows of spherical cells 10 sandwiching the convex portions 37 b are connected by bonding wires 39.
Alternatively, instead of the bonding wire 39, a conductive paste, metal, metal clip, wire bond, ultrafine particle, or the like may be used.
[0056]
In addition, in one row of the spherical cells 10 in the recess 37a, the first conductive semiconductor layer 11 may be n-type and the second conductive semiconductor layer 12 may be p-type. Thereby, the series connection of the circuit using this semiconductor device is realizable.
[0057]
In each of the above embodiments, the first conductivity type is assumed to be p-type and the second conductivity type is assumed to be n-type. However, the first conductivity type can be similarly manufactured even if the second conductivity type is assumed to be p-type. . Moreover, although the spherical cell which uses a p-type polycrystal as a spherical substrate was used, you may use a p-type single crystal or p-type amorphous silicon.
[0058]
Although the solar cell has been described in the first and second embodiments, it can also be applied to a light emitting element. That is, by using a light emitting element such as a light emitting diode as a spherical cell and forming a reflective surface in the recess so that light from the light emitting element can be efficiently guided forward, the light emitting efficiency is extremely high. A high light emitting element can be obtained.
[0059]
【The invention's effect】
As described above in detail, according to the solar cell, the semiconductor device, the method for manufacturing the solar cell, and the method for manufacturing the semiconductor device according to the present invention, the adhesion strength between the substrate and the sphere cell is secured by fixing the sphere cell in the recess. Since it is strong and chemically stable, the product life can be extended.
In addition, since the inner wall of the recess is used as a reflection surface, and incident light is efficiently guided to the light receiving surface of the solar cell, the light receiving efficiency can be improved, and a highly efficient and highly reliable solar cell can be obtained.
In addition, since a plurality of spherical cells are arranged in a line along the longitudinal direction in the concave portion of the substrate with unevenness, even if the spherical cells have a slight variation in diameter and shape, a regular arrangement is easy. Further, by providing a groove in the recess, the regular arrangement can be simplified and the adhesion strength between the substrate and the spherical cell can be increased.
In addition, since it is easy to switch between series and parallel circuits, output control can be simplified.
Furthermore, since the manufacturing process can be simplified, the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a solar cell according to a first embodiment.
FIG. 2 is a schematic cross-sectional view illustrating the solar cell according to the first embodiment.
FIG. 3 is a schematic cross-sectional view illustrating manufacturing steps (a) to (e) of the method for manufacturing the solar cell according to the first embodiment.
FIG. 4 is a perspective view of a main part of a solar cell according to a second embodiment.
FIG. 5 is a schematic cross-sectional view illustrating a solar cell according to a second embodiment.
FIG. 6 is a schematic cross-sectional view illustrating manufacturing steps (a) to (f) of a method for manufacturing a solar cell according to a second embodiment.
FIG. 7 is a perspective view of relevant parts of a semiconductor device according to a third embodiment.
FIG. 8 is a schematic cross-sectional view illustrating a semiconductor device according to a third embodiment.
FIG. 9 is a schematic cross-sectional view illustrating manufacturing steps (a) to (f) of a method for manufacturing a semiconductor device according to a third embodiment.
FIG. 10 is a schematic cross-sectional view illustrating a conventional solar cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Spherical cell 10a Ground surface 11b Polycrystalline silicon layer 11 1st conductivity type semiconductor layer 12 2nd conductivity type semiconductor layer 13 Conductive resin 14 Insulation resin 15, 25, 35 P-type electrode 16, 26, 36 Conductive paste 17 Insulating resin substrate 17a, 27a, 37a Concave portion 17b, 27b, 37b Convex portion 17c, 27c, 37c Reflective surface 23, 33 Bonding pad 24, 34 Insulating film 27, 37 Metal substrate (n-type electrode)
28, 38a, 38b Groove 29, 39 Bonding wire

Claims (11)

A substrate having a concave portion in which at least a part of the side wall constitutes a reflective surface , and fixed to a side wall opposite to the reflective surface in the concave portion so as to receive reflected light from the reflective surface ; and A solar cell comprising: a spherical cell in which a part of the concave wall surface facing the reflective surface of the concave part is cut off .   2. The sun according to claim 1, wherein a plurality of concave portions of the substrate are arranged in parallel, and a plurality of the spherical cells are arranged in a row along the longitudinal direction in each of the concave portions. battery.   The groove has a groove extending in the longitudinal direction of the concave portion on the bottom surface of each of the concave portions, and a plurality of the spherical cells are arranged in a row so as to engage the spherical cells with the groove. 1. The solar cell according to 1.   The solar cell according to claim 1, wherein the concave portion is filled with a light transmissive resin.   A substrate having a recess has two rows of grooves formed at predetermined intervals along the longitudinal direction on the bottom surface of the recess, and a plurality of grooves are engaged with the two rows of grooves. A semiconductor device comprising spherical cells arranged in two rows. Preparing a substrate having a concave portion in which at least a part of the side wall constitutes a reflecting surface;
A plurality of spherical cells each having a second conductivity type semiconductor layer formed on the surface of the first conductivity type semiconductor layer, in contact with the concave portion of the substrate, respectively, on the side wall opposite to the reflecting surface in the concave portion; Arranging and fixing in a line along the longitudinal direction;
A step of excising a part of the spherical cell on the concave wall surface facing the reflective surface of the concave;
Electrically connecting the substrate or the conductive pattern provided on the substrate and the second conductive semiconductor layer exposed in the cut portion of the spherical cell;
Forming a contact on the first conductive semiconductor layer of the spherical cell;
A method for manufacturing a solar cell, comprising: electrically connecting an electrode formed on the substrate and the contact of the first conductive semiconductor layer. Preparing a substrate having a plurality of recesses in which at least a part of the side wall constitutes a reflecting surface, and having a groove extending in the longitudinal direction of the recesses on the bottom surface of each of the plurality of recesses;
A plurality of spherical cells each having a second conductivity type semiconductor layer formed on the surface of the first conductivity type semiconductor layer are in contact with a side wall opposite to the reflecting surface in each recess so as to engage with the groove. And aligning and fixing in a line along the longitudinal direction;
A step of excising a part of the spherical cell on the concave wall surface facing the reflective surface of the concave;
Electrically connecting the substrate or the conductive pattern provided on the substrate and the second conductive semiconductor layer exposed in the cut portion of the spherical cell;
Forming a contact on the first conductive semiconductor layer of the spherical cell;
A method for manufacturing a solar cell, comprising: electrically connecting an electrode formed on the substrate and the contact of the first conductive semiconductor layer. Two rows of grooves each having a plurality of recesses in which at least a part of the side wall constitutes a reflecting surface, and having a predetermined interval along the longitudinal direction on the bottom surface of each of the plurality of recesses Preparing a substrate having
A spherical cell having a second conductive type semiconductor layer formed on the surface of the first conductive type semiconductor layer is fixed so that a plurality of spherical cells are arranged in two rows so as to engage with the two rows of grooves. Electrically connecting to a substrate or a conductive pattern provided on the substrate;
Forming a contact on the first conductive type semiconductor layer of the spherical cell;
A method of manufacturing a semiconductor device, comprising: electrically connecting an electrode formed on the substrate and a contact of the first conductivity type semiconductor layer.   In the step of forming a contact on the first conductive type semiconductor layer of the spherical cell, grinding is performed so as to remove a part of the spherical cell, and the ground surface of the spherical cell is formed on the first conductive type semiconductor layer. 9. The method of manufacturing a semiconductor device according to claim 8, wherein the contact is formed by forming a bonding pad.   The method for manufacturing a semiconductor device according to claim 9, wherein the ground surface of the spherical cell and the convex portion of the substrate are formed at the same height.   The method for manufacturing a solar cell according to claim 6 or 7, wherein the cut surface of the cut portion of the spherical cell and the convex portion of the substrate are formed at the same height.

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