JPH0518277B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a plurality of photoelectric conversion elements (also simply referred to as elements) in which a non-single crystal semiconductor including an amorphous semiconductor having at least one PN or PIN junction is provided on a transparent insulating substrate. The present invention relates to a method of manufacturing a photoelectric conversion device using a laser, which is electrically connected in series and generates a high voltage. [Prior Art and its Problems] One of the methods for manufacturing a semiconductor device uses a laser scribe. This uses computer-controlled laser light to process and process semiconductors and conductive films.
Since the device is formed by removing it, it becomes a maxless process, which is a manufacturing method particularly suitable for mass production of photoelectric conversion devices. Conventionally, silver or aluminum, which is a light reflective metal, has been used on the oxide conductive film of a photoelectric conversion semiconductor device. However, since these metals are not sublimable (easily vaporized by laser light) and have high thermal conductivity, they were found to be unsuitable as materials capable of laser scribing. Furthermore, silver has poor adhesion to the oxide conductive film and is easily peeled off. Aluminum undergoes an oxidation reaction at the interface with the oxide conductive film and becomes an aluminum oxide insulator. For these reasons, improvements to each layer on the oxide conductive film have been required. [Object of the Invention] An object of the present invention is to provide a method for scribing an oxide conductive film well when manufacturing a semiconductor device by laser scribing. [Means for Solving the Problems] In order to solve the above problems, the present invention provides an oxide conductive film on a non-single crystal semiconductor on a substrate, which is in close contact with the semiconductor, and a conductive oxide film on the upper surface by magnetron sputtering. A step of forming a multilayer film having a metal film mainly composed of chromium, and a step of forming an open groove by selectively removing the multilayer film by irradiating the multilayer film with laser light. It is characterized by having the following. The present invention also provides a step of forming a plurality of first electrode regions by irradiating a conductive film on a substrate having an insulating surface with a laser beam to form a first trench, and a step of forming a plurality of first electrode regions by forming a plurality of first trenches. forming a non-single crystal semiconductor having at least one PN or PIN junction on an electrode region; and irradiating the semiconductor on each of the first electrode regions with a laser beam to selectively remove the semiconductor. forming a second groove exposing the first electrode; forming an oxide conductive film on the semiconductor and in the second groove; and forming a chromium layer on the upper surface by magnetron sputtering. a step of forming a multilayer film having a metal film whose main component is a metal film, and irradiating the multilayer film with a laser beam to selectively remove the multilayer film to form a third groove and forming a plurality of grooves. and a step of separating into two electrode regions, thereby:
the first electrode in each of the first electrode regions;
It is characterized in that an element is formed in which a semiconductor and a second electrode are laminated, and one of the elements and an element adjacent to it are connected in series. This invention forms a multilayer film having an oxide conductive film on a non-single-crystal semiconductor on a substrate and a metal film containing chromium as a main component on the upper surface of the oxide conductive film using magnetron sputtering method, and laser beams are applied to this multilayer film. By irradiating the film with , it is possible to selectively remove and form an open trench without damaging the semiconductor underneath the film or damaging it only to a depth of 500 Å or less. The arrangement, size, and shape of elements in the device of the present invention are determined by design specifications. However, in order to simplify the content of the present invention, in the following detailed description, the first electrode on the lower side (substrate side) of the first element and the second electrode on the right side of the first electrode will be described. 2
This description is based on the case where the electrodes (on the semiconductor, that is, on the side away from the substrate) are electrically connected in series. In such a configuration, the third groove for separating the second electrodes of the first element and the second element from each other is made of indium oxide or tin oxide in close contact with the P or N type non-single crystal semiconductor layer. Laser light is irradiated to scribe the multilayer film, which has an oxide conductive film mainly composed of chromium and a metal film mainly composed of chromium (hereinafter simply referred to as chromium) formed on the upper surface by magnetron sputtering method. It is formed by doing the following. That is, the present invention provides a second
The conductor for the electrode is scribed using a laser beam,
The electrodes are separated from each other, but at that time, they are exposed to laser light at a high temperature of 1800℃.
In order to prevent the underlying non-single-crystal semiconductor, especially the hydrogenated amorphous semiconductor, from becoming polycrystalline and becoming conductive, a laser scribe is performed by laminating sublimable chromium on a sublimable oxide conductive film. By making a compound of the semiconductor under the third trench,
It also prevents the semiconductor from becoming polycrystalline due to laser annealing. In addition, for example, 500% of chromium is added onto the oxide conductive film.
It was formed to a thickness of ~5000 Å. Experiments have shown that the oxide conductive film and chromium do not undergo interfacial oxidation because chromium has heat resistance (melting point 1800°C, boiling point 2660°C) and sublimation, and is a material that does not easily react with other materials. It turned out to be true. Furthermore, the sheet resistance could only be obtained from 10 to 30 Ω/□ (thickness 2000 Å) using the conventionally known electron beam method. Using the magnetron sputtering method, this becomes 0.7 to 3Ω/□ (thickness 2000Å), about 1/10
I was able to do it. In addition, the ohmic contact with chromium was also good, which was extremely desirable. This invention is maskless. This process is effective for producing a connecting part that connects two elements using a laser scribing method. The details of the invention are shown below with reference to the drawings. [Example] FIG. 1 is a longitudinal sectional view showing the manufacturing process of the present invention. In the drawings, a transparent substrate 1 having an insulating surface, such as a glass plate (for example, a thickness of 0.6 to 2.2 mm, for example, 1.2
mm, length (in the left-right direction in the drawing) 60 cm, width 20 cm). Furthermore, a light-transmitting conductive film such as ITO (indium oxide/tin oxide mixture, i.e., a film in which 10% by weight of tin oxide is added to indium oxide) (approximately 1500 Å) + SnO ₂ (200 to 400
) or a translucent conductive film (1500~2000
Å) was formed by vacuum evaporation, LPCVD, plasma CVD, or spraying. After this, YAG laser processing machine (manufactured by Nippon Laser)
A power of 0.1 to 3 W (focal length 40 mm) was applied depending on the wavelength (1.06 μ or 0.53 μ), and a spot diameter of 20 to 70 μφ (typically 50 μφ) was controlled by a microcomputer. Furthermore, this irradiated laser beam is scanned to form a first groove 13 which is a scribe line,
The first electrode 2 was fabricated in each element region 31, 11. The first open groove 13 formed by this first laser scribe has a width of approximately 50μ and a length of 20cm.
Each of the electrodes of the light-transmitting conductive film was completely cut off, and each element region was electrically separated to form a first electrode. Thereafter, a non-single crystal semiconductor layer 3 for generating photovoltaic force by light irradiation is formed on the upper surface of the electrode 2 and the groove 13 by plasma CVD or LPCVD.
It was formed to a thickness of 0.8μ, typically 0.5μ. A typical example is a P-type semiconductor (SixC _1-x x=0.8 approx.
100 Å) - I-type amorphous or semi-amorphous silicon semiconductor (approximately 0.5 μ) - Semiconductor silicon having N-type microcrystals (approximately 500 Å)
SixC _1-x x=0.9 about 50Å is stacked to form one PIN
Non-single crystal semiconductor with junction or P-type semiconductor (SixC _1-x ) - I type, N type, P type Si semiconductor - I type
SixGe _1-x semiconductor - two types of N-type Si semiconductor
Tandem type with PIN junction and one PN junction
PINPIN...This is the semiconductor 3 of PIN junction. The non-single crystal semiconductor 3 was formed to have a uniform thickness over the entire surface. Furthermore, as shown in FIG.
The open grooves 18 were formed by a second laser scribing process. In this drawing, the first and second open grooves 13, 18
The centers of the two are shifted by 100μ. The second open groove 18 thus exposed the side surfaces 8, 9 and/or the top surface of the first electrode. In FIG. 1, as shown in FIG. 2C, a second electrode 4 and a connector 30 on the back side are formed on the top surface, and a third An open groove 20 was obtained. The second electrically conductive film 4 is formed by forming oxide conductive films 45, 45', which is a feature of the present invention, in close contact with a P or N type semiconductor. Its thickness is 100~3000Å
It was formed to a thickness of . As this oxide conductive film, ITO (a mixture whose main components are indium oxide and tin oxide) 45 was formed on the N-type semiconductor layer. It is also possible to form this oxide conductive film using dium oxide or tin oxide as a main component. This ITO is extremely susceptible to wrap-around during film formation. For this reason, it is enough to enter Group 7,
It became possible to electrically connect well with the bottom surface 6 of the transparent conductive film 37. These use a reactive sputtering method in which oxygen is added to prevent the semiconductor layer from deteriorating.
It was formed at a temperature below .degree. This oxide conductive film, ITO, is extremely important in the present invention. [1] The metals 46 and 46' of the second electrode do not form an alloy layer with the silicon 3, which prevents them from being abnormally diffused into the semiconductor 3 and causing a shot between the upper and lower electrodes. . That is, it is useful for improving reliability at the back electrode-semiconductor interface in high-temperature storage tests at 150 to 200°C. [2] When forming the third open groove 20 of the present invention, the laser scribing metal 46 enters the semiconductor 3 due to the high temperature of 1800° C. or higher of the laser beam, especially in the scribing region 20, and the metal 46 for laser scribing penetrates into the semiconductor 3 between the electrodes 39 and 38. This can prevent leakage current of 10 ^-7 A/cm or more from occurring. Therefore, it is possible to prevent a decrease in manufacturing yield due to the formation of the third open groove. [3] By forming an oxide conductive film that is compatible with P or N type semiconductors on the semiconductor, that is, N
An oxide conductive film containing indium oxide as a main component is provided on the ITO or P-type semiconductor layer in close proximity to the type semiconductor to lower the contact resistance between the semiconductor and the electrode, improving fill factor and conversion efficiency. be able to. [4] A contact is formed with the side surface or the side surface and the top surface of the first electrode 37 of the first element in the connecting portion 12 due to the strong wraparound, and since they are both oxides, this contact portion will prevent the contact from occurring at the interface during long-term use. No increase in insulation properties. That is, if there is contact between a metal such as aluminum and the transparent conductive film 37, the metal will react with the oxygen of the transparent conductive film over a long period of time, producing insulation at this interface. In the oxide-oxide contact using a conductive film, such insulation does not occur at the contact interface, and reliability is greatly improved. [5] Promote the reflection of long-wavelength light that is not absorbed within the semiconductor 3 in the incident light 10 by the reflective metal 46, and in particular, make the ITO thickness 900 to 1400 Å, preferably an average thickness of 1050 Å, and a length of 600 to 800 nm. This is effective in increasing the reflection of wavelength light and improving conversion efficiency. [6] The connector is also composed of this oxide conductive film,
Because it is adjacent to the sensitive active layer of semiconductors, especially PIN semiconductors, it prevents metal migration. It was also found that chromium is an excellent metal on the oxide conductive film. Experimentally, it was found to be an ideal metal without removing the semiconductor layer by laser scribing. To improve this low optical reflectance of chromium and thus improve the conversion efficiency of the device, 0.1-50% by weight of copper or silver in chromium, e.g. 2.0-10%
% by weight was added. That is, the back electrode is (1) oxide conductive film (100 to 3000 Å) Cr (300 to 5000 Å)
(2) Oxide conductive film (100-3000Å) Cr-Cu (2.5
%) (300-5000Å), (3) Oxide conductive film (100-1500Å) Cr-Ag (2.5
%) Cr (300-5000 Å) had excellent workability for laser scribing. Next, in the present invention, in order to prevent the connector 30 of the oxide conductive film 45 constituting the second electrode from electrically shorting, the third groove 20 is formed so that the semiconductor underneath it is not damaged or It was provided over the first element region 31 so as to cause damage only to a depth of 500 Å or less. That is, by forming a multilayer film of the oxide conductive film of the present invention and chromium on its upper surface, these respective components interact, vaporize, and scatter during laser beam irradiation, so that the amorphous silicon underneath is formed. It does not polycrystallize or remove non-single-crystalline semiconductors,
It has been experimentally found that this is an ideal symmetrical electrode for laser irradiation. As a result of this step, the electrical isolation between the electrodes 39 and 38 where the open circuit voltage of the first element is generated is achieved by applying a laser beam (20 to 100μφ, typically 50μφ) to the second open groove 18.
They were formed at a distance of about 100μ from each other. That is, the third
The center of the open groove 20 is provided on the first element side at a depth of 50 to 200 μm, typically 100 μm, compared to the center of the second open groove 30. This shows the case where the second electrode 4 is cut and separated by irradiating the laser beam of the third laser scribe from above to form the open groove 20. Furthermore, the semiconductor layer under this groove 20 is heated at room temperature to 200°C.
℃ oxidation atmosphere (1 to 10 days of oxidation) or plasma oxidation atmosphere (100 to 250℃ for 1 to 5 hours) to form silicon oxide 34 to a thickness of 100 to 1000 Å, and then form the two electrodes 39. , 38 was further prevented. In this way, as shown in FIG. 1C, a photoelectric conversion device in which a plurality of elements 31, 11 are directly connected by the connecting portion 12 was able to be manufactured. FIG. 1D shows an attempt to further complete the present invention as a photoelectric conversion device, that is, a silicon nitride film 2 is made by plasma vapor phase method as a passivation film.
1 was uniformly formed to a thickness of 500 to 2000 Å to further prevent leakage current between each element due to adsorption of moisture, etc. Furthermore, an external lead-out terminal was provided at the peripheral portion 5. These were filled with an organic resin 22 such as polyimide, polyamide, Kapton or epoxy. In this way, the photovoltaic force generated by the irradiation light 10 flows from the first electrode of the first element to the second electrode of the second element from the bottom contact as shown by the arrow 32.
I was able to connect them in series. As a result, each element on this board (60 cm x 20 cm) has a width of 14.35 mm, a width of the connecting part of 150 μm, a width of the external lead electrode part of 10 mm, and a peripheral part of 4 mm.
There are 40 stages within mm x 192 mm, and the effective area (192 mm x
14.35 mm 40 stages 1102 cm ² or 91.8%). If the segment has a conversion efficiency of 10.8% (1.05cm), the panel has a conversion efficiency of 7.7% (theoretically it would be 9.8%, but the effective conversion efficiency was reduced due to the resistance of the 40-stage connection) (AM1 [100mW /cm ² ]),
It was possible to have an output power of 8.1W. Furthermore, when this panel is subjected to a high temperature storage test at 150℃, the percentage decreases to below 10% after 1000 hours, for example, 20 panels.
The worst case scenario was a decline of only 4% (X = 1.5%). This is an astonishing value considering that when conducting a reliability test under the same conditions using the conventional mask method, as many as 17 panels were rendered inoperable in 10 hours. FIG. 2 is a longitudinal cross-sectional view and a plan view (end portion) showing the most typical positional relationship of the grooves formed in three laser scribing steps. The numbers and steps are the same as in FIG. FIG. 2A shows the first open groove 13, the first element 31,
It has a second element 11 and a connecting part 12. Furthermore, the second groove 18 is provided across the first electrode 2 side of the semiconductor 3 that constitutes the first element, and both of these are removed. A group 7 is also fabricated by side etching to connect the oxide conductive film of the second electrode to the bottom surface 6 of the first electrode. This third open groove 20 is shifted toward the first element 31 side to a depth of about 60μ. Therefore, the right end portion of the third open groove 20 is slightly (approximately 10μ) closer to the first element 3 than the part of the connector portion 30.
It is provided over one side. Further, by long-term oxidation at low temperature, oxide insulator 3
4, the second electrodes 4 of the first and second elements 31, 11 are electrically cut and separated from each other, and leakage between these electrodes is also reduced to 10 ^-7 A/cm.
(meaning on the order of 10 ^-7 A per 1 cm width). FIG. 2B shows a plan view, and at its end (lower side in the drawing) the first, second and third open grooves 13,
18 and 20 are provided. Furthermore, at the end of the element (lower side of the drawing), the first electrode 2 was cut and separated at 13'. Further, this was covered with the semiconductor 3 and the material of the second electrode 4, and furthermore, this second electrode conductor 4 was separated by a third groove 50 at an outer end portion than 13'. This longitudinal section is similar to the end section of FIG. 3A. In this case as well, a passivation film is formed to cover these open grooves 50. In this drawing, the widths of the first, second, and third opening grooves are 70 to 20μ, and the width of the connecting portion is typically 350 to 80μ, typically 200μ. By reducing the spot diameter of the above YAG laser based on the technical concept, the area required for this connection can be reduced, and the effective area (effective efficiency) as a photoelectric conversion device can be further improved. have. FIG. 3 shows the external lead electrode section of the photoelectric conversion device. 3A corresponds to FIG. 1, the external extraction electrode section 5 has a pad 49 that contacts the external extraction electrode 47, and this pad 49 is connected to the second electrode (upper electrode) 4. ing. At this time, even if the pressure applied to the electrode 47 is too strong and the pad 49 penetrates the semiconductor 3 underneath and comes into contact with the first electrode 2, the groove 13' is provided to prevent the pad 49 and 2 from being shot. Further, the outer part is cut and separated by an open groove 50 which is formed by simultaneously scribing the first electrode, the semiconductor, and the second electrode with one laser scribe. Furthermore, FIG. 3B shows that another pad 48 connected to the lower first electrode 2 is made of a second electrode material at 18'.
They are connected to each other. Furthermore, the pad 48 is in contact with the external extraction electrode 46 and is electrically connected to the outside. Here again, the pad 48 is completely electrically isolated from the adjacent photoelectric conversion device by the opening grooves 18', 20'', and 50, and the bottom contact with the first electrode 2 is formed at 18' at 6. In other words, the photoelectric conversion device is covered with an organic resin mold 22 except for the electrode parts 5 and 45, which improves the moisture resistance.
By combining 2, 4 or 1 piece of 20cm, 40cm x 120cm in an aluminum sash or carbon fiber frame, you can create a package of 120cm x 40cm NEDO.
It is possible to provide panels for standard high power. It is also effective for NEDO standard panels to have a fluorine-based protective film attached to the reflective surface side (upper side in the drawing) of the photoelectric conversion device of the present invention using Seaflex to increase mechanical strength against wind pressure, rain, etc. be. In the present invention, glass is particularly used as the substrate among light-transmitting insulating substrates. However, it is effective to use as this substrate a composite substrate in which organic resin, aluminum oxide, silicon oxide or silicon nitride is formed on a thin film of flexible organic resin, aluminum, stainless steel, etc. to a thickness of 0.1 to 2 μm. Further, the details of the present invention will be supplemented by describing examples below. [Specific Example] This example will be shown according to the drawing in FIG. That is, the thickness of chemically strengthened glass as the transparent substrate 1
1.1 mm, length 60 cm, and width 20 cm were used. A silicon nitride film with a thickness of 0.1 μm was applied to this upper surface to form a blocking layer. Furthermore, on top of that, CTF is ITO1600Å + SnO ₂ 300Å
was fabricated by electron beam evaporation. Furthermore, after this, the first open groove was made with a spot diameter of 50μ.
A YAG laser with an output of 1 W was controlled by a microcomputer at a scanning speed of 3 m/min. Furthermore, the first electrode semiconductor was scanned in a rectangular manner at a position 5 mm inside the glass edge at the edge of the panel using a laser beam output of 1 W to prevent an electrical short circuit with the frame of the panel. The element regions 31 and 11 were 15 mm wide. After this, the well-known PCVD method was used to create the image shown in Figure 2.
A non-single crystal semiconductor with one PIN junction was fabricated. Its thickness was approximately 0.5μ. After this, the first element 3 is removed by 100μ from the first groove.
By shifting 1, the output is 1W with a spot diameter of 50μφ.
A second open groove 18 was formed by laser scribing in the atmosphere as shown in FIG. 2B. Furthermore, ITO was applied as an oxide conductive film to the entire surface using a reactive sputtering method to an average film thickness of 1050 Å.
Furthermore, chromium was formed on the upper surface to a thickness of 1000 to 1500 Å by the Macnetron sputtering method, thereby forming the second electrode 45 and the connector 30.

〔Effect of the invention〕

According to the present invention, a multilayer film including an oxide conductive film and a metal film mainly composed of chromium is formed on the top surface of the oxide conductive film on a non-single-crystal semiconductor on a substrate using a magnetron sputtering method, and a laser beam is applied to this multilayer film. By irradiating the semiconductor with light, it can be made without polycrystallization.
In addition, it was possible to selectively remove and form open trenches without damaging the semiconductor or damaging it only to a depth of 500 Å or less. In addition, interfacial oxidation could be prevented. Furthermore, by using the magnetron sputtering method, the sheet resistance can be reduced to 0.7~3Ω/□ (thickness 2000Ω/□).
Å) compared to the conventional electron beam method. In addition, the ohmic contact with chromium was also good, which was extremely desirable.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the manufacturing process of a photoelectric conversion device according to the present invention. FIG. 2 is a longitudinal sectional view of a photoelectric conversion device according to the present invention. FIG. 3 is a partially enlarged longitudinal sectional view of another photoelectric conversion device according to the present invention.

Claims (1)

[Scope of Claims] 1. On a non-single crystal semiconductor on a substrate, an oxide conductive film in close contact with the semiconductor, and a metal film containing chromium as a main component formed on the upper surface by magnetron sputtering method. A method for manufacturing a semiconductor device, comprising the steps of: forming a multilayer film having a laser beam; and forming an open groove by selectively removing the multilayer film by irradiating the multilayer film with a laser beam. 2. A step of irradiating a conductive film on a substrate having an insulating surface with a laser beam to form a first trench to form a plurality of first electrode regions, and a step of forming a plurality of first electrode regions on the first trench and the electrode region. At least one PN or PIN junction
a second step of irradiating the semiconductor on each of the first electrode regions with a laser beam to selectively remove the semiconductor to expose the first electrode; a step of forming an open groove; a multilayer comprising an oxide conductive film on the semiconductor and in the second open groove; and a metal film containing chromium as a main component formed on the upper surface by a magnetron sputtering method; a step of forming a film; and a step of selectively removing the multilayer film by irradiating the multilayer film with a laser beam to form a third groove and separating the multilayer film into a plurality of second electrode regions. As a result, the first electrode, the semiconductor, and the second electrode are provided in each of the first electrode regions.
An element with laminated electrodes is formed, and
A method for manufacturing a semiconductor device, characterized in that one of the elements and an element adjacent thereto are connected in series.