JPH03194975A - Manufacture of photoelectric converter - Google Patents

Abstract

PURPOSE:To ensure breakdown strengths between adjacent unit cells and between the transparent electrodes of the cells and a rear surface electrode by emitting a laser light through a substrate to remove a metal film together with an amorphous semiconductor layer disposed under the film, separating into respective cells, and emitting the light from the rear electrode side to the light emitted part. CONSTITUTION:When a photoelectric converter composed of unit cells in which transparent electrodes 21, 22, amorphous semiconductor photoelectric conversion layers 31, 32 and rear surface metal electrodes 41, 42 are laminated on a light transmission insulating gold plate 1 is manufactured, the electrodes 21, 22 and the layers 31, 32 of the cells are entirely covered with a metal film 4, a laser light 51 is emitted through the metal 1 to remove the film 4 together with the amorphous semiconductor layer under the film 4 and to separate it into the electrodes 41, 42 of the cells, and then a laser light 52 is emitted from the electrodes 41, 42 side to the emitted part of the light 51. Thus, even if the metal film is not completely removed due to a dust existing on a board and the electrodes are not completely separated, the remaining metal film is removed by the emission of the laser from the electrode sides. Accordingly, the electrodes can be completely separated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a transparent conductive film formed on a transparent insulating substrate,
The present invention relates to a method for manufacturing a photoelectric conversion device in which a plurality of unit cells are formed by separately processing an amorphous semiconductor film and a metal film.

[Conventional technology]

In a photovoltaic conversion device such as a solar cell that converts the light energy of sunlight into electrical energy by a junction formed by an amorphous semiconductor such as amorphous silicon (hereinafter referred to as a-Sl), a high output voltage is usually required. In order to obtain this, a configuration in which multiple unit cells are connected in series is used. Each unit cell often has a structure in which a transparent electrode made of a transparent conductive film, a photoelectric conversion layer made of A-3ill, and a back electrode made of a metal film are laminated on a transparent insulating substrate.

In order to obtain such a structure, a transparent conductive film + a S
A T film or a metal film is formed on the entire surface of an insulating substrate, and each film is separated and divided into unit cells.
A method in which the back electrode of one unit cell is brought into contact with the transparent electrode of an adjacent unit cell has been adopted as a method that facilitates mass production. Separation processing of the i3 bright conductive film and the a-3i film is performed by laser irradiation, but if laser irradiation is used to separate the metal film, the underlying a-51 film will also be affected by it, resulting in lower resistance. In order to avoid such a phenomenon, as known in Japanese Patent Application Laid-Open No. 63-274183, YAG laser light is irradiated through the transparent electrode of the transparent insulating substrate 1 to evaporate the a-Sl film and to There is a method to scatter the metal film.

[Problem to be solved by the invention]

When separating the back electrodes by laser light irradiation from the above-mentioned translucent insulating substrate, if there is dust on the surface of the substrate that blocks the passage of light, a metal bridge will be formed on the back electrodes of adjacent unit cells, and the back electrodes will be separated. There was a problem with short circuits occurring between the electrodes.

Another problem is that the side surface of the amorphous semiconductor layer in contact with the portion evaporated by laser beam irradiation becomes microcrystalline due to heating and becomes low in resistance, resulting in a decrease in the withstand voltage of the back electrode and the transparent electrode.

The object of the present invention is to eliminate the above-mentioned problems and to provide a photoelectric conversion device in which back electrodes are separated between adjacent unit cells, and furthermore, a photoelectric conversion device in which breakdown voltage between transparent electrodes and back electrodes of the same unit cell is guaranteed. A method of manufacturing a conversion device is provided.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a method for manufacturing a photoelectric conversion device comprising a unit cell formed by laminating a transparent electrode, an amorphous semiconductor photoelectric conversion layer, and a back metal electrode on a transparent insulating substrate. In the method, a transparent electrode of each unit cell;
The entire surface of the photoelectric conversion layer is covered with a metal film, and the metal film is removed together with the amorphous semiconductor layer underneath by irradiating laser light through the substrate. After separating into the back electrode of each unit cell, the laser light irradiation is performed. Assume that the laser beam is irradiated onto the portion from the back electrode side. Alternatively, in the above method for manufacturing a photoelectric conversion device, the transparent 1 of each unit cell is covered with a metal film, the entire surface of the photoelectric conversion layer is covered with a metal film, and the parallel 2
It is assumed that the metal film is removed together with the amorphous semiconductor layer underneath by irradiating a laser beam onto the line, and the back electrodes of each unit cell are separated. Furthermore, a transparent electrode is placed on a translucent insulating substrate.

A photoelectric conversion device in which unit cells formed by laminating an amorphous semiconductor photoelectric conversion layer and a back metal electrode are connected in series by bringing the edge of the back electrode of one unit cell into contact with the edge of the transparent electrode of an adjacent unit cell. In the manufacturing method of
The entire surface of the transparent electrode and photoelectric conversion layer of each unit cell is covered with a metal film, and the metal film is removed together with the amorphous semiconductor layer underneath by irradiating laser light through the substrate, and the back electrode of each unit cell is coated with a metal film. After separation, the edge of the back electrode opposite to the edge in contact with the transparent electrode of the adjacent unit cell is removed by irradiation with laser light from the back electrode side.

[Effect]

When separating the back electrode by removing the metal film together with the amorphous semiconductor layer by laser beam irradiation through the transparent insulating substrate, the metal film was not completely removed due to dust on the substrate, so the back electrode Even if the separation between the two electrodes is not complete, the remaining metal film is removed by laser beam irradiation from the back electrode side, so that the back electrode can be completely separated.

In addition, if the metal film is removed in two parallel lines by irradiating a laser beam through a transparent insulating substrate, the metal film will remain in both removed areas and the back electrode will be completely separated. The probability of not being there is low.

After removing the metal film by irradiating laser light through the transparent insulating substrate, the edge of the back electrode on the side that does not contact the transparent electrode inside the removed part is removed by irradiating laser light from the back electrode side. For example, since the distance between the back electrode and the transparent electrode at the edge of one unit cell becomes longer, the breakdown voltage between the two electrodes is guaranteed even if the resistance becomes low due to microcrystallization of the amorphous semiconductor due to laser light irradiation. be done.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 fal to tel are process diagrams of one embodiment of the present invention, in which a transparent conductive film is formed on a glass substrate l, laser patterning is performed, and after separation into transparent electrodes 21 and 22, A-5iM with a thickness of 44,000 to 5,000 layers having a p-1-n junction is formed and laser patterned, separated into photoelectric conversion layers 31 and 32, and then metal W such as a
144 (Fig. 8) 0-order YAG laser beam is irradiated through 5 beams and 1 lath substrate 1, and the metal film is coated with a-5t.
It was removed together with the membrane and separated into back electrodes 41 and 42 (Figure b
), at this time, if there is dust on the substrate, the laser beam 51 is locally blocked, causing the metal bridge 43 and the a
-5l film 33 remains. FIG. 2 shows this metal bridge in plan view. The shaded area 61 in FIG.
Then, as shown in FIG. The metal film and the a-3t film 33 underneath it were removed.

When patterning a gold m film by laser light irradiation, it is normal to increase the laser output, and at that time a -5i1
! A short circuit between the back electrode and the transparent electrode is likely to occur due to the lower resistance of l, but in this case, it is only necessary to eliminate the short circuit due to the metal bridge 43, so the laser beam 52 can be weakened, and the a-3t layer Microcrystallization can also be prevented.

FIG. 3 (4) to TO) are process diagrams of another embodiment of the present invention; FIG. 3 Ta), (bl is FIG. 1 Ta),
(Similar to BL, but in FIG. 3 (C1), the laser beam 52 is irradiated through the glass substrate 1 in the same way as the laser beam, and the area 61 removed by the laser beam 51 is spaced apart from the area 61.
The region 62 of 0- was removed together with the a-3i layer. As a result, as shown in Fig. 4, the number of short circuits per minute #1 wire 100 cs is as follows: In the case of the solar cell according to this example, which is indicated by a black circle, the number of short circuits per minute #1 line 100 cs is calculated by irradiating the laser beam only once, which is indicated by a white circle, and This was a greater decrease than in the case of buttered solar cells.

FIG. 5 (al to tel shows the process diagram of yet another embodiment of the present invention, FIG. 5 fa), (bl is the first
Although similar to Figures (al and (bl), in Figure 5 (C1) the laser beam 52 is not irradiated directly above the gap between the back electrodes 41 and 42, but is irradiated in a shifted manner, as shown in Figure 6. The area 62 adjacent to the metal film removal portion 61 is removed by irradiation of the laser beam 51 from the substrate side.In this case as well, the irradiation of the laser beam 52 prevents short-circuiting between the front electrode 41 and the metal bridge 43. The laser beam 52 could be weakened because it was only necessary to eliminate the presence of some metal residue in the metal film removal part 62.Furthermore, in the end, the back surface electrode 8i
Since the creepage distance between 41 and the transparent electrode 21 is increased, even if the resistance of the a-S+ film is lowered to some extent, reverse breakdown voltage defects that tend to occur at the edge of the back electrode are greatly reduced. FIG. 7 shows 10 pieces of separated cotton for the solar cell manufactured according to this example.
The short circuit occurrence rate and withstand voltage per 0 x are shown in the figure (al
and Figure (black circle in BL, white circle shows the case of a conventional example in which the laser is irradiated only once from the glass substrate side and patterned with the back electrode. The incidence of short circuits is greatly reduced in solar cells with a flow of 10 lofts. However, the withstand voltage is clearly improved, which shows the usefulness of the present invention.In addition, in FIG. Since no reverse breakdown voltage is applied, it is meaningless to perform the second gold rl & film removal on this side.

〔Effect of the invention〕

According to the present invention, after the metal film is removed together with the underlying amorphous semiconductor layer by laser light irradiation through the transparent insulating substrate, the laser light is irradiated again, and in this case, the metal film is removed at the bottom. By irradiating the exposed area from the back electrode side, by removing the metal film parallel to the area at a distance, or by removing only the metal film adjacent to the area, the back surface can be Even if a metal bridge remains in the electrode separation part, it is now possible to significantly reduce short circuits between adjacent back electrodes. Furthermore, if the metal film adjacent to the initial separation part is removed, the creepage distance between the two electrodes where the reverse breakdown voltage is applied becomes longer, and even if the resistance of the amorphous semiconductor layer surface is lowered by laser light irradiation, the reverse It was possible to obtain a photoelectric conversion device in which a decrease in breakdown voltage could be prevented, the number of defective products was small, and the reverse breakdown voltage was greatly improved.

[Brief explanation of drawings]

FIG. 1 shows the steps of one embodiment of the present invention (al, (b)
). (A cross-sectional view shown in the order of C1, FIG. 2 is a plan view showing a defect that occurs between the back electrodes during laser irradiation through a transparent insulating substrate, and No. 3ri!J is a process of another embodiment of the present invention. ial, (bl, TCI), FIG. 4 is a diagram showing the number of short circuits for each loft of solar cells according to the example shown in FIG. 3 and the conventional method, and FIG. 5 is a diagram showing another short circuit. The steps of one embodiment of the present invention are (al, (b), (C1
6 is a plan view of the part between the back electrodes of the solar cell shown in FIG. 5, and FIG. 7 is a comparison of the solar cell according to the embodiment shown in FIG. Ml
is a diagram showing the number of short circuits occurring for each loft, and (false) is a diagram showing the distribution of withstand voltage between both electrodes. Figure 2 Figure 1 Figure 5]

Claims (1)

[Scope of Claims] 1) In a method for manufacturing a photoelectric conversion device comprising a unit cell formed by laminating a transparent electrode, an amorphous semiconductor photoelectric conversion layer, and a back metal electrode on a transparent insulating substrate, each unit The entire transparent electrode and photoelectric conversion layer of the cell are covered with a metal film, and the metal film is removed together with the amorphous semiconductor layer underneath by irradiating a laser beam through the substrate. After separating into the back electrode of each unit cell. . A method for manufacturing a photoelectric conversion device, characterized in that the laser beam irradiation portion is irradiated with a laser beam from the back electrode side. 2) In a method for manufacturing a photoelectric conversion device consisting of a unit cell formed by laminating a transparent electrode, an amorphous semiconductor photoelectric conversion layer, and a back metal electrode on a transparent insulating substrate, the transparent electrode of each unit cell, the photoelectric conversion layer The entire surface of the conversion layer is covered with a metal film, and laser light is irradiated on two parallel lines through the substrate to remove the metal film along with the amorphous semiconductor layer underneath, and separate the back electrodes of each unit cell. A method for manufacturing a photoelectric conversion device, characterized by: 3) A unit cell is formed by laminating a transparent electrode, an amorphous semiconductor photoelectric conversion layer, and a back metal electrode on a transparent insulating substrate, and the edge of the back electrode of one unit cell is connected to the edge of the transparent electrode of an adjacent unit cell. In a method for manufacturing photoelectric conversion devices that are connected in series by contacting the unit cells, the transparent electrode and photoelectric conversion layer of each unit cell are entirely covered with a metal film, and a laser beam is irradiated through the substrate to cover the metal film underneath. After removing the amorphous semiconductor layer along with the back electrode of each unit cell, the edge of the back electrode opposite to the edge that contacts the transparent electrode of the adjacent unit cell is irradiated with laser light from the back electrode side. 1. A method for manufacturing a photoelectric conversion device, characterized in that removal is performed by.