JPH0550152B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention provides a non-single-crystal semiconductor including an amorphous semiconductor having at least one junction that can generate photovoltaic force upon irradiation with light on a transparent insulating substrate. The present invention relates to a method for manufacturing a semiconductor device in which a plurality of photoelectric conversion elements (also simply referred to as elements) are electrically connected in series to generate a high voltage.

[Conventional technology and its problems]

Conventionally, one of the methods for manufacturing an integrated photoelectric conversion device
One method is to use laser scribing.

This laser scribe enables precise formation and maskless processing under computer control, making it extremely suitable for mass production and capable of producing high-performance products when manufacturing large-area integrated photoelectric conversion devices. This was an excellent manufacturing method.

However, in the past, for example, when a semiconductor on a transparent conductive film was removed using a laser to form an open groove, if the laser was simply scribed on the semiconductor, oxygen in the atmosphere and silicon would react. In addition, the surface of the transparent conductive film has become insulating due to the mixed compound of the transparent conductive film and lower silicon oxide.

Furthermore, since it is difficult to control the depth, the transparent conductive film under the semiconductor is likely to be damaged.

Therefore, for example, even if an attempt was made to form an electrical connection using the open groove, a good contact could not be made.

[Purpose of the invention]

An object of the present invention is to provide a manufacturing method that can satisfactorily scribe a non-single crystal semiconductor on a transparent conductive film when manufacturing a semiconductor device by laser scribing.

[Means for solving the problem] In order to achieve the above object, the present invention forms a metal film containing chromium as a main component on a non-single-crystal semiconductor formed on a transparent conductive film. The method is characterized in that the metal film in the irradiated area and the non-single crystal semiconductor under the metal film are removed by irradiating the film with laser light.

The present invention also provides a step of forming a plurality of first electrode regions by irradiating a transparent conductive film on a substrate having an insulating surface with a laser beam to form first grooves, and forming a plurality of first electrode regions. forming a non-single-crystal semiconductor that generates photovoltaic force by light irradiation on the groove and the electrode region, and a metal film containing chromium as a main component on the non-single-crystal semiconductor; and on each of the first electrode regions. By irradiating the non-single-crystal semiconductor layer under the film through the metal film, the metal film in the irradiated area and the non-single-crystal semiconductor layer under the metal film are removed. forming a conductive film on the remaining metal film and within the second groove; and irradiating the conductive film with a laser beam. forming a third trench to separate the plurality of second electrode regions, whereby the first electrode and the non-single crystal semiconductor layer are separated into each of the first electrode regions. , a metal film, and a second electrode are formed, and a second electrode of an adjacent element is placed on the exposed first electrode of one of the elements. It is characterized by extending and connecting the elements in series.

The present invention also provides a step of forming a plurality of first electrode regions by irradiating a transparent conductive film on a substrate having an insulating surface with a laser beam to form first grooves, and forming a plurality of first electrode regions. forming a non-single-crystalline semiconductor that generates photovoltaic force by light irradiation on the groove and the electrode region, and a metal film containing chromium as a main component on the non-single-crystalline semiconductor; and each of the first electrode regions. By irradiating the non-single crystal semiconductor layer below the film through the metal film above, the metal film in the irradiated area and the non-single crystal semiconductor under the metal film are removed. forming a second trench by exposing the first electrode; removing the remaining metal film; and forming a conductive film on the remaining non-single crystal semiconductor and in the second trench. and a step of irradiating the conductive film with a laser beam to form a third trench to separate the conductive film into a plurality of second electrode regions. An element in which the first electrode, a non-single crystal semiconductor layer, and a second electrode are stacked is formed on each of the elements, and a layer is formed on the exposed first electrode of one of the elements. The device is characterized in that the second electrodes of adjacent devices extend to connect the devices in series.

The arrangement, size, and shape of elements in 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 of the second element disposed on the right side thereof will be described. 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.

The present invention provides a heat-resistant, low-thermal-conductivity conductor, such as a metal mainly composed of chromium, on the upper surface of a non-single-crystal semiconductor, and when the semiconductor underneath is selectively removed by laser scribing through the conductor, light is transmitted through the conductor. The fact that a conductive film can be manufactured without any damage is effective for manufacturing a connecting portion of a semiconductor device, particularly a photoelectric conversion device.

In other words, the present invention was discovered experimentally,
If a heat-insulating, non-oxidizing material such as chromium, which has high heat retention properties due to its low thermal conductivity and heat resistance, is formed on this semiconductor, the chemical reaction caused by laser scribing will occur between the silicon and the transparent conductive film. It has been found that under certain conditions, it is possible to selectively vaporize only silicon using heat, without causing this phenomenon.

Therefore, the upper surface of the light-transmitting conductive film is also substantially free from any damage and can be rendered conductive.

This chromium is sublimable, that is, easily vaporized by laser irradiation, making it suitable for laser processing.

Furthermore, chromium is a typical example of metals with low thermal conductivity. Furthermore, make ohmic contact with the semiconductor,
In addition, it is stable in long-term use at high temperatures ranging from room temperature to 150°C, so it has the advantage of no deterioration at the electrode-semiconductor interface.

In the structure of transparent conductive film-semiconductor-chromium, the semiconductor whose main component is silicon has sublimation properties, and the chromium thereon has oxidation resistance and a high melting point, so it has heat resistance. In addition, since there is little reflected light from the laser beam, the chromium itself and the semiconductor underneath can be heated to a sufficiently high temperature by the irradiation light.

Furthermore, since the thermal conductivity is low, this heat is not propagated laterally and dissipated.

That is, since chromium has a high melting point and low thermal conductivity, it is possible to locally store heat up to a high temperature.

Therefore, the silicon in the irradiated area is heated to a temperature higher than the vaporization temperature and is vaporized, causing it to burst outward.

At this time, the light-transmitting conductive film, which is more difficult to vaporize than silicon, remains as it is with its surface exposed underneath.

In addition, even if this surface is exposed due to the heat of vaporization of silicon, the light-transmitting conductive film will not change in quality due to temperature.

With this configuration, the second groove for connecting the first element and the second element can be formed by removing the non-single crystal semiconductor while also forming the first electrode of the first element. The conductive film could be fabricated by laser scribing without being removed.

As a result, the conductive film constituting the second electrode of the second element was extended and brought into contact with the upper surface of the first electrode of the first element, thereby forming a good connection part.

The details of the invention are shown below with reference to the drawings.

Example 1 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 (left and right in the drawing) 60cm, width 20cm),
Transparent organic resin or silicon nitride film on this resin
A composite organic resin formed to a thickness of 300 to 2000 Å was used.

Furthermore, a translucent conductive film such as ITO (indium tin oxide mixture) is applied to the entire upper surface.
In _other words, a film in which 10 wt. ~20,000 Å) was formed by vacuum evaporation, LPCVD, plasma CVD, or spraying.

After this, an output of 1 to 3 W (focal length 40 mm) is applied using a YAG laser processing machine (wavelength 1.06 μ or 0.58 μ, manufactured by Nippon Laser), and the spot diameter is typically 20 to 70 μφ.
50μφ was controlled by a microcomputer.
Furthermore, this irradiated laser beam was scanned to form first grooves 13 as scribe lines, and first electrodes 2 were produced 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.

After that, a non-single crystal semiconductor layer 3 is formed on the upper surface of the electrode 2 and the groove 13 by a known plasma CVD method or optical CVD method to generate a photovoltaic force by light irradiation.
It was formed to a thickness of 0.2 to 1.0μ, 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 Non-single crystal semiconductor with x=0.9 approximately 50 Å stacked and one PIN 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 a semiconductor 3 of PIN junction.

The non-single crystal semiconductor 3 was formed to have a uniform thickness over the entire surface, covering all the first electrodes and the grooves.

Furthermore, a film 4 containing chromium as a main component (hereinafter referred to as chromium) was formed on the upper surface of this semiconductor by electron beam evaporation.

Since chromium has low conductivity, it is desirable that the film be thick, but if it is too thick, stress distortion tends to occur.

Therefore, the film thickness was set to 300 to 4000 Å depending on the laser output range during scribing.

Next, as shown in FIG.
The open grooves 18 were formed by a second laser scribing process.

This second open groove is shown in the second element 11.
It is sufficient that the position is 30 μ or more to the left of the side surface 16 of the first electrode, and it is shifted by 30 to 200 μ toward the first element side.
That is, it is characterized in that it is provided over the first electrode position of the first element, and a portion 9' of the first electrode is left to provide a manufacturing margin.

Such a structure, that is, the transparent conductive film 2
- Semiconductor 3 - In chromium, the semiconductor whose main component is silicon has sublimation properties, and the chromium above it has oxidation resistance and a high melting point, so it has heat resistance. In addition, since there is little reflected light from the laser beam, the chromium itself and the semiconductor underneath can be heated to a sufficiently high temperature by the irradiation light.

In addition, since the thermal conductivity is low, this heat does not propagate laterally and dissipate, and the silicon in the irradiated area is vaporized at a temperature higher than the vaporization temperature and scatters outward like a burst. At this time, the light-transmitting conductive film, which is more difficult to vaporize than silicon, remained as it was with its surface exposed underneath.

In addition, even when this surface was exposed 8 due to the heat of vaporization of silicon, the light-transmitting conductive film did not change in quality due to temperature.

Thus, as shown in FIG.
It has become possible to expose the upper surface 8 of.

Thus, the second open groove 18 was formed by entering the interior 9 of the first electrode 37 of the first element 31, as shown in FIG. 1B.

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 upper surface 8 of the first electrode.

Of course, by increasing the average power in laser scribing and removing this transparent conductive film, the side surface or side surface and upper surface edge of the transparent conductive film are exposed in a width of 1 to 5 μm ( This is also possible because semiconductors are more easily vaporized than transparent conductive films.

Furthermore, this substrate may be etched with dilute hydrofluoric acid (1/10HF, which is 48% HF diluted with 10 times water, was used here) for 10 seconds to 1 minute, typically by applying ultrasonic waves for 30 seconds. good.

In FIG. 1, this chromium was left as is and formed part of the second electrode.

Furthermore, as shown in FIG. 1C on this top surface,
Second electrode 6 and connecting part (connector) 3 on the back side
0 was formed.

Conductive oxide films 45, 45' were formed as conductors constituting this connecting portion.

This conductive oxide film 7 is made of ITO (a mixture whose main components are indium oxide and tin oxide).
45 was formed. It is also possible to form this conductive oxide film using indium oxide as a main component.

When this ITO is formed to a thickness of 500 to 3000 Å, for example 1500 Å, by electron beam evaporation, CVD, or PCVD, wrapping is more likely to occur during film formation than other metals. For this reason, it was able to fully enter the second groove 18 and electrically connect well with the bottom surface 8 of the transparent conductive film 37, thereby making it possible to form a contact structure.

In other words, the conductive oxide film does not migrate into the semiconductor 3 due to the connection part because the conductor constituting the connector 30 forms a compound as an oxide from the beginning, and the conductive oxide film does not migrate into the semiconductor 3 due to the connection part. High reliability could be achieved without forming an insulator at the interface with the conductive oxide film 30 due to oxidation reaction.

Nickel is deposited on this conductive oxide film to a thickness of 100 to 1000 Å.
It is effective to perform vacuum evaporation to a thickness of 100 mL to facilitate external connections.

In the embodiment of the present invention, reflective metals such as silver and aluminum are added at the interface with the semiconductor under the chromium.
It was effective to improve the conversion efficiency of the photoelectric conversion device by forming it thinly to a thickness of ~500 Å.

Next, in order to configure this second electrode, a third groove 20 was provided across the first element region 31.

That is, the electrode 3 where the open circuit voltage of the first element is generated
Electrical isolation between the grooves 9 and 38 was formed by laser beams of 20 to 100 .mu..phi. (typically 50 .mu..phi.) at a distance of about 50 .mu. from the second open groove 18. That is, the center of the third open groove 20 is provided on the first element side at a depth of 30 to 200 μm, typically 100 μm, compared to the center of the second open groove 30.

In FIG. 1C, the second electrode 4 is thus
This figure shows the case where the laser beam of the third laser scribe is irradiated from above to cut and separate the grooves 20 to form the open grooves 20.

In order to contain the thermal energy applied to the silicon by the heat-resistant conductor chromium 46 in the third groove, all of the semiconductor in the laser irradiated part is removed in the same manner as in the formation of the second groove, and The surface of the electrode is exposed.

At this time, since the vaporization of silicon was performed in a bursting manner, the semiconductor side periphery of the third trench became polycrystalline and it became possible to normally fabricate the element 31 without being shot.

It is effective to perform passivation by oxidizing the side surfaces of the exposed semiconductor.

In this way, as shown in FIG. 1C, a photoelectric conversion device in which a plurality of elements 31 and 11 were connected in series at the connecting portion 12 could 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 through the bottom contact as shown by the arrow 32, thereby making it possible to connect them in series.

And if the segment has a conversion efficiency of 10.3% (1.05cm), then in a 10cm x 10cm panel 8.6
% (Theoretically it would be 9.4%, but the effective conversion efficiency decreased due to the resistance of the 12-stage connection) (AM1 [100m
W/cm ² ]), it was possible to have an output power of 0.83W.

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 16 panels would become inoperable in 10 hours.

Example 2 FIG. 2 shows a method for manufacturing another photoelectric conversion device of the present invention. The process will be briefly described in correspondence with FIG.

In FIG. 2A, the transparent conductive film 2 on the substrate 1, the first groove, and the non-single crystal semiconductor were fabricated in the same manner as in FIG.

Next, a material having low thermal conductivity and a high melting point, that is, a material that stores the heat of the laser beam and does not easily react with the semiconductor, was formed as a coating 4 on the upper surface.

The coating 4 was formed by electron beam evaporation of a metal containing chromium as a main component for the conductor, and by plasma vapor deposition of silicon nitride for the insulator.

Further, as in FIG. 1B, a second groove 18 was formed by laser scribing to expose the surface 8 of the first electrode 37.

In addition, the coating 4 shown in FIG. 2B was removed by etching.

For etching chromium, use nitric acid, cerium chloride,
Etching was carried out using a mixture of ammonium, perchloric acid, and water, and hot phosphoric acid for etching silicon nitride.

Thus, Figure 2B was obtained.

Furthermore, conductive oxides 45 and 45' were formed as second electrodes on this upper surface by electron beam evaporation of ITO. In addition, metals whose main component is chromium 4
6,46' was produced.

After this, a third open groove as shown in FIG. 2C was formed. This third trench 20 was then able to selectively remove the vicinity without damaging the semiconductor. In addition, the upper part of the groove in the semiconductor was thinly oxidized by this surface, and the oxidation made it possible to passivate the insulator 34.

Further, in FIG. 2D, a silicon nitride film for a passive basin and a coating insulating film 22 were fabricated as shown in FIG. 1D.

Also this panel for example 40cm x 60cm or 60cm x
A 120cm x 40cm NEDO is packaged by combining 2, 4 or 1 piece of 20cm, 40cm x 120cm in an aluminum sash or carbon fiber frame.
It is possible to provide panels for standard high power.

In addition, it is also effective for this NEDO standard panel to increase its mechanical strength against wind pressure, rain, etc. by attaching a fluorine-based protective film using Seaflex to the reflective surface side (upper side in the drawing) of the photoelectric conversion device of the present invention. It is.

〔Concrete example〕

A specific example of this 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 10 cm, and width 10 cm were used.

Furthermore, a textured CTF (having a fiber structure) was fabricated on top of this by electron beam evaporation using ITO 1600 Å + SnO ₂ 300 Å.

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 shape at the edge of the panel at a position 1.5 mm inside the glass edge using a laser beam output of 1 W (corresponding to Fig. 1 13') to create an electrical short circuit between the panel frame and the element. was prevented.

The element regions 31 and 11 were 8 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 0.6μ.

Furthermore, chromium 4 was added by electron beam evaporation method.
It was fabricated to a thickness of 3000 Å. After this, the first element 31 is shifted 100μ from the first groove, and the second groove 1 is formed by laser scribing in the atmosphere with a spot diameter of 50μφ, an output of 1W, and a scanning speed of 30mm/min.
No. 8 was prepared as shown in FIG. 1B.

Further, the entire substrate was immersed in 1/10HF for 30 seconds to remove the oxide insulator in the open grooves and expose the surface 8 of the transparent conductive film. Furthermore, ITO was applied as a conductive oxide film to the entire surface using electron beam evaporation to give an average film thickness.
It was fabricated to a thickness of 1050 Å by electron beam evaporation to form parts 45 and 45' of the second electrodes 38 and 39, and in addition, the connector 30 was formed.

Furthermore, a third open groove 20 was similarly formed by a third laser scribe to a depth of 100 μm from the second open groove 18, shifted toward the first element 31 side, to obtain FIG. 1C. The laser beam has an output of 1W,
The other conditions were the same as those for producing the second open groove.

Thereafter, a silicon nitride film with a thickness of 1000 Å was formed at a temperature of 200° C. by the PCVD method to form a passivation film 21.

By connecting 12 stages of elements to a 10cm x 10cm panel, they were able to create an effective area of 88%.

AM1 (100mW/cm ² ) as the effective efficiency of the panel
We were able to obtain an output of 8.6% and an output of 0.83W.

As the light-transmitting substrate 1 in the present invention, a light-transmitting organic resin such as Sumilato 1100 manufactured by Sumitomo Bakelite Co., Ltd.
By further overlapping the protective organic resin 22 on the upper side, it is possible to create a structure in which the photoelectric conversion device is sandwiched between the organic resin sheets, which has flexibility and can be mass-produced at extremely low cost. It became.

The second groove in the present invention is provided over the entire width of the non-single crystal semiconductor.

However, by making a hole using this as a part, or by leaving the semiconductor at the periphery of the panel and forming an opening only inside, a structure can be created to prevent shortening between the respective elements at the periphery of the connection part. That is valid.

In FIGS. 1 and 2, the hole was incident from the lower transparent insulating substrate.

However, in the present invention, the light incident side is not limited to the lower side, and it is also possible to use ITO as the upper electrode and irradiate light from the upper side, and the substrate is not a glass substrate but a flexible transparent organic resin. It is possible to use a substrate.

〔Effect of the invention〕

According to the present invention, a heat-resistant, low thermal conductivity metal mainly composed of chromium is provided on the upper surface of a non-single-crystal semiconductor formed on a transparent conductive film, and laser scribing is performed through this metal. It has become possible to selectively remove the semiconductor by laser scribing without any damage to the transparent conductive film.

As a result, good contact could be obtained in the method for manufacturing a connecting portion that connects two elements using a laser scribing method, which is a maskless process.

In the case of a photoelectric conversion device, particularly a thin film type photoelectric conversion device, the present invention provides that each of the thin film layers, such as a conductive layer for an electrode or a semiconductor layer, each have a thickness of 500 Å.
~1μ, 0.2~1.0μ thin, and by using a laser scribing method, it was possible to manufacture it with a computer-controlled automatic mask alignment mechanism.

The present invention enables a maskless process that does not use a mask at all, is extremely simple and highly accurate, and reduces the manufacturing cost of the device.As a result, manufacturing at 500 yen/W is possible, and the manufacturing scale can be reduced. We were able to provide an extremely standard photoelectric conversion device that could be expanded to cost 100 to 200 yen/W.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the manufacturing process of a photoelectric conversion device in an embodiment according to the present invention. FIG. 2 is a longitudinal sectional view showing the manufacturing process of a photoelectric conversion device in another embodiment of the present invention.

Claims (1)

[Claims] 1. A metal film containing chromium as a main component is formed on a non-single-crystal semiconductor formed on a transparent conductive film, and the metal film is irradiated with a laser beam. 1. A method for manufacturing a semiconductor device, comprising removing the metal film at the top and the non-single-crystal semiconductor under the metal film. 2. A plurality of first grooves are formed by irradiating a laser beam onto a transparent conductive film on a substrate having an insulating surface to form a first groove.
a non-single-crystal semiconductor that generates photovoltaic force by light irradiation on the first groove and the electrode region; and a metal film containing chromium as a main component on the non-single-crystal semiconductor. irradiating the non-single crystal semiconductor layer under the film with laser light through the metal film on each of the first electrode regions, thereby removing the metal film and the metal in the irradiated portion. removing the non-single crystal semiconductor under the film to expose the first electrode to form a second trench; and forming a conductive film on the remaining metal film and in the second trench. and a step of irradiating the conductive film with a laser beam to form a third trench to separate the conductive film into a plurality of second electrode regions. The first electrode, the non-single crystal semiconductor layer, the metal film, and the second electrode, respectively.
An element with laminated electrodes is formed, and
the exposed first of one of the elements;
A method for manufacturing a semiconductor device, characterized in that a second electrode of an element adjacent to the element extends over the electrode of the element, so that the elements are connected in series. 3. A plurality of first grooves are formed by irradiating a laser beam onto a transparent conductive film on a substrate having an insulating surface to form a first groove.
a non-single-crystal semiconductor that generates photovoltaic force by light irradiation on the first groove and the electrode region; and a metal film containing chromium as a main component on the non-single-crystal semiconductor. irradiating the non-single crystal semiconductor layer under the film with laser light through the metal film on each of the first electrode regions, thereby removing the metal film and the metal in the irradiated portion. removing the non-single crystal semiconductor under the film to expose the first electrode and forming a second trench; removing the remaining metal film; and removing the remaining non-single crystal semiconductor. above and said second
a step of forming a conductive film in the open groove; and a step of irradiating the conductive film with a laser beam to form a third open groove and separating it into a plurality of second electrode regions. , an element in which the first electrode, a non-single crystal semiconductor layer, and a second electrode are stacked is formed in each of the first electrode regions, and the exposed area of one of the elements is formed. A method for manufacturing a semiconductor device, characterized in that a second electrode of an element adjacent to the element extends over the first electrode, so that the elements are connected in series.