JPH0535582B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention involves laminating a semiconductor thin film and a metal electrode layer on a plurality of transparent electrodes arranged in a row on a single translucent insulating substrate, dividing each layer by parallel cut parts, and connecting a plurality of transparent electrodes in series. The present invention relates to a method for manufacturing a thin film solar cell consisting of individual unit cells.

[Prior art and its problems]

Amorphous semiconductor films formed by glow discharge decomposition of raw material gas or photo-CVD are vapor-phase grown, so in principle they can be easily grown to a large area, and are expected to be used as low-cost solar cell materials. In order to efficiently extract the electric power generated from such an amorphous solar cell, it is desirable that the solar cell device be shaped as shown in FIG. 3, for example, and have a structure in which unit cells are connected in series. In this structure, transparent electrodes 21, 22, 23, 24, . , 34..., and then metal electrodes 41, 42, 43, 44... are formed in this order. Then, the patterns of both electrodes and the amorphous layer are constructed so that the transparent electrode of one unit cell partially contacts the metal electrode of the adjacent unit cell. Laser scribing technology has recently come to be used to form such patterns. This has the advantage that the number of patterning steps is reduced compared to when conventional photoetching is used, and costs can be reduced. In patterning using laser scribe,
First, a beam condensed from a laser, usually a YAG laser, is swept over a transparent conductive film formed on the entire surface of the substrate 1, and the rectangular transparent electrodes 21, 2 are swept.
2, 23... are formed. An amorphous layer is formed on the entire surface, and then similarly divided by sweeping a focused laser beam to form strip-shaped amorphous layer regions 31, 32, 33, . . . . FIG. 4 shows a patterned transparent electrode 21,
A state in which the amorphous layer 3 is deposited on the entire surface of the amorphous amorphous layer 22 and 23, and then the cut portion 8 is formed is shown. However, in this case, if the laser output is too small to completely cut the amorphous layer 3 as shown in part A,
The metal electrode 42 provided thereon is the transparent electrode 23
Since the unit cells are not connected to each other and the series connection of the unit cells is interrupted, no output is generated from the solar cells. Furthermore, if the laser output is too large, the transparent electrode 24 will be cut as shown in part B, and the contact area between the metal electrode 43 and the transparent electrode 24, which will be formed subsequently, will become small, making it impossible to establish a low-resistance connection. On the other hand, when the metal layer 4 is formed on the entire surface of the patterned transparent electrode and amorphous layer as shown in FIG. 5, and the metal layer is divided using a YAG laser, the laser beam output is adjusted when cutting the amorphous layer. It is even more difficult than That is, if the laser output is small, the metal layer 4 will not be completely cut and adjacent unit cells will be short-circuited as shown in section C.
Furthermore, if the output is too large, the problem arises that the transparent electrode 23 is also cut off at the same time, as shown in section D, and the connection between the unit cells is cut off.
It is necessary to find the optimum conditions for the laser output so that only the metal layer 4 is cut, but this is very difficult. Moreover, when mass production is aimed at, it is a major drawback that processing must be performed while finding the optimum conditions for the laser output, which differs for each solar cell device. Furthermore, if there are variations in the thickness or reflectance of the metal layer, there will be parts that cannot be cut even when swept with a laser of a constant output, or parts that will cut even the transparent electrode.

[Purpose of the invention]

The present invention solves the above-mentioned problems and provides a method for manufacturing thin-film solar cells that allows easy selection of cutting conditions for dividing metal electrode layers or semiconductor thin films, and that can be performed quickly, reliably, and at low cost. The purpose is to provide.

[Key points of the invention]

In the present invention, at least one of a semiconductor thin film and a metal layer laminated on a plurality of transparent electrodes is attached to a to-be-processed layer by bringing a tip of an ultrasonic machining tool connected to an ultrasonic transducer into contact with the to-be-processed layer. The above-mentioned objective is achieved because the cutting is performed by moving the cutting layer relative to the cutting edge, and the layer to be processed can be reliably cut using ultrasonic energy without affecting the underlying layer. Arranging a plurality of ultrasonic machining tools in a line and simultaneously contacting and cutting the layer to be processed is effective in forming a strip pattern at a higher speed.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, in which ultrasonic waves generated by an ultrasonic vibrator 51 made of a piezoelectric element such as barium titanate attached to a support 7 are transmitted to the cutting tool via a horn 52. It is focused at the tip of 6. The cutting tool 53 has a conical shape, and the tip of the cutting tool 53 contacts the layer 1 to be processed on the solar cell substrate 1.
0. The amorphous layer or metal electrode layer is crushed and peeled off by ultrasonic energy. Therefore, by sweeping the support 7 or the substrate 1, a conditional pattern of an amorphous layer or a metal electrode layer is formed. By using an ultrasonic transducer with a frequency of several tens of kHz to 100 kHz and an output of several tens of W, it is possible to
Patterns with a width of m to several hundred μm can be cut at a high speed of ten to several tens of cm/sec. In an amorphous solar cell, as shown in Figure 3,
Transparent electrodes 21 to 24 made of SnO ₂ or the like are formed. The patterning can be easily performed by laser scribing technology using a YAG laser or the like. However, when cutting the amorphous semiconductor layer formed thereon as shown in FIG. 4, it is necessary to avoid damaging the transparent electrode and leaving no semiconductor layer. When using a laser, it is difficult to adjust the laser output, but
According to the invention, for example, the frequency is 20kHz, the output is 10W
An amorphous amorphous layer with a width of 100 μm can be easily crushed and peeled off at a speed of 30 cm/sec using an ultrasonic vibrator of 1, to form divided amorphous layers 41 to 44, and moreover, it can be formed on a glass substrate 1. _SnO2
It has been found that the transparent electrodes 21 to 24 made of films or the like are not damaged by ultrasonic energy. Therefore, it is easy to selectively cut only the amorphous layer. As shown in FIG. 5, in the patterning of the metal layer 4 formed on the entire surface of the amorphous semiconductor layer, the output of the ultrasonic transducer and the sweep speed with respect to the substrate are set under the same conditions as in the processing of the amorphous layer, based on the present invention. Al, Ag,
It was found that metal layers such as Cu can be cut with good selectivity without damaging the underlying amorphous layer. If the output of the ultrasonic transducer is too large or the sweep speed is too slow, the underlying amorphous layer will also be cut at the same time, but even in this case, the transparent electrode will not be damaged as described above. , does not cause deterioration of solar cell characteristics. FIG. 2 shows another embodiment in which ultrasonic cutting tools 61, 62, 63, etc. as shown in FIG. Place the dividing lines 81, 8 in one sweep.
This shows a method for simultaneously performing patterning of 2, 83, . . . .

【Effect of the invention】

According to the present invention, when patterning the semiconductor thin film and metal electrode layer of a series-connected thin film solar cell, by using an ultrasonic processing tool, the semiconductor thin film and metal layer can be easily cut compared to a transparent conductive film. This makes it possible to process with better selectivity than the conventional laser scribing method, and eliminates the risk of disconnection of unit cells. Cutting speeds of several tens of centimeters per second can be easily achieved, which is comparable to laser methods. In addition, the ultrasonic machining tools themselves are not very expensive, and by arranging multiple ultrasonic machining tools in a row, low-cost machining can be realized even if a method that enables patterning with a single sweep is used. Benefits can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a perspective view showing another embodiment, FIG. 3 is a sectional view of an amorphous solar cell, and FIGS. 4 and 5 are sectional views showing an intermediate stage of the manufacturing process. 1: Solar cell substrate, 51: Ultrasonic vibrator, 5
2: Horn, 6, 61, 62, 63: Ultrasonic cutting tool, 81, 82, 83: Parting line, 10: Layer to be processed.

Claims (1)

[Claims] 1. A semiconductor thin film and a metal electrode layer are stacked on a plurality of transparent electrodes arranged in a row on a single transparent insulating substrate, and each is divided by parallel cutting parts and connected in series. In the method of manufacturing a solar cell consisting of multiple unit cells, at least one of a semiconductor thin film and a metal electrode layer is moved relative to the processed layer by bringing the tip of an ultrasonic processing tool into contact with the processed layer. A method for producing a thin film solar cell, the method comprising: cutting a thin film solar cell; 2. In the method described in claim 1,
A method for manufacturing a thin-film solar cell, which comprises arranging a plurality of ultrasonic processing tools in a row and simultaneously contacting and cutting a layer to be processed.