JPS61251132A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To perform the linear patterning for a photo-electric transducer by a method wherein a light-transmissive conduction film with heat-resistivity is provided as a backside reflection electrode, and a metallic lamination coating is provided on it as a metallic conduction electrode. CONSTITUTION:A light-transmission conductive film is formed on a substrate 1 which has light-transmissivity and insulative surface, the first open groove 14 is formed on this substrate, and the first electrode 37 is formed in each inter-element region 31 and 32. After this, an irregular crystalline semiconductor layer 3 is formed on the surface of it. The second open groove 15 is formed on the first element side of the first open groove 14. Then, an aluminum layer 25 is formed on it. After that, it is cut and separated with laser to form plural, second electrodes 39 and 38 so as to obtain the third open groove 6. A laminated coating made of the light-transmission conductive film 15 and the aluminum layer 25 is used for the second conductive film 5. Thus, a photo-electric transducer element which serially connects the plural elements 31 and 32 at the connecting section 4 is obtained. Further, a silicon nitride film 21 is formed as a passivation film. Finally, external take out terminals 22 and 22' are provided on the circumference.

Description

[Detailed Description of the Invention] ``Field of Industrial Use'' This invention forms a laminated film for electrodes, such as aluminum or an alloy film mainly composed of aluminum, on a transparent conductive film on the upper surface of a semiconductor, and The present invention relates to a method for manufacturing a semiconductor device in which a laser patterning process (hereinafter referred to as LP) is performed by irradiating a film with laser light having a wavelength of 400 nm or less, such as excimer laser light.

This invention is a non-single-crystal semiconductor including an amorphous semiconductor having at least one junction capable of generating photovoltaic force when irradiated with light, and a photoelectric conversion element (also simply referred to as an element) is fabricated by using a laser patterning method on a substrate having an insulating surface. ) is electrically connected in series to produce a photoelectric conversion device capable of generating high voltage.

``Prior Art J'' Conventionally, aluminum has been used as the back electrode of semiconductor devices, especially photoelectric conversion devices.However, although this aluminum is suitable for forming electrodes using a mask, it is not suitable for laser processing. The maskless process used originally has strong chemical reactivity with oxidizing gases or silicon semiconductors,
In addition, since it is a non-sublimable material, YAG laser light (wavelength 1.
This material was completely unsuitable as a material for laser scribing using 06μ).

Problems to be Solved by the Invention Particularly when aluminum is to be formed closely on a semiconductor, heat treatment at 150° C. causes the aluminum to react with the semiconductor, promoting thermal deterioration. For this reason, a method is known in which ITO (indium oxide) is interposed between the eyebrows as a glabellar material.

Although this structure has excellent deterioration resistance, it is not sufficient to integrate the cells on the same substrate.

Therefore, the back surface of each cell is made of an underlying semiconductor, such as Si/IT.
An integration method is known that has an O/Al electric scratch structure and uses only metal contacts in the electric bridge portion without using CTF.

(Japanese Unexamined Patent Publication No. 55-108780) However, in order to simplify the manufacturing process, it is required that the connecting portion be made of the same material as the back electrode. To this end, it is required to perform laser patterning on the laminated film without damaging the underlying semiconductor and without electrical leakage between adjacent cells, allowing integration.

However, conventionally known YAG laser light (wavelength 500n)
If a thickness of 0.53 μm or more (for example, 0.53 μm or 1.06 μm) is used, the underlying semiconductor, especially the amorphous semiconductor, is inevitably scribed and damaged.

For this reason, it has come to be considered that laser processing is impossible with a laminated structure of ITO/AI as a back electrode material.

``Means for Solving the Invention J The present invention has a highly reliable chain structure having heat resistance, which is important for such a semiconductor device, especially a photoelectric conversion device, and a transparent conductive film effective as a reflective electrode on the back surface, and a transparent conductive film thereon. The metal conductive film may be aluminum or a metal containing aluminum as a main component (AI-Cu, Al-Cr).

It uses a laminated film of (including Al-Mo, Al-Ag). Further, the present invention relates to such a multilayer film, which is subjected to laser patterning by irradiating the film with pulsed laser light (pulse width: 50 ns or less) of 400 nm or less, preferably 300 nm or less. This patterning was achieved without removing the underlying non-single crystal semiconductor from the patterning surface.

Furthermore, in the present invention, such laser patterning of ultraviolet light is not achieved by scanning dotted laser light, but by irradiating it in a linear manner (medium 10 to 300μ), and using this linear pulsed light. The same area was irradiated one to several times.

r Effect 1 Since the present invention performs linear patterning, the effective processing speed is 10 to 30 times that of dotted laser beam scribing. In addition, the photoelectric conversion device can be expected to have high efficiency as a photoelectric conversion device, and can be made at a low price. In addition, the photoelectric conversion device can be manufactured using a semiconductor with a thin film structure of 0.5 to 5 μm on a glass substrate. However, for the first time, it has become possible to manufacture it without using any masks.

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 of the second element disposed on the right side thereof will be described. The pattern 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.

Then, at this specified position, a pulsed light laser (excimer laser KrF, wavelength 249
nm maximum pulse power 450mJ light area 8s+m
33+wm 200 with quartz cylindrical lens
The same linear portion was repeatedly irradiated with 1 to 5 pulses (the beam was focused into a linear beam of μ×33III11).

Since it is a linear beam, it is possible to scribe the entire line area with one pulse.

"Example 1" In this example, a CTP (transparent conductive film) (2) is provided on a glass substrate (1), and a non-single-crystal semiconductor (3) having a PIN junction is further provided on the glass substrate (1), and this substrate is used as a base substrate. On top of this, a two-layer film of aluminum or CTF (15) /AI (25) is applied as a back electrode (5).
A three-layer film of F/Ag/AI was formed and the thickness of the aluminum film was varied and evaluated.

Furthermore, laser patterning was performed on the substrate having this surface to be processed using an excimer laser that focused linearly with a cylindrical lens.

A summary is shown in Table 1 below.

In addition, Fig. 1 (
Shown in C). As shown in the drawing, the processing section (6) was able to selectively remove only the back electrode without damaging the surface of the semiconductor or removing the semiconductor.

As shown in the conventional example shown in FIG. 1(B), this is 1.0
When scanning processing is performed using a YAG laser beam with a wavelength of 6μ (pulse width approximately 100 ns), a bulge (7) is observed at the end of the laser processing.

This bulge is a mixture of silicon, CTF, and aluminum, and is neither conductive nor insulating, and not only is it prone to leaks, but as is clear from the drawing, it also scribes the underlying semiconductor film. It was completely unusable.

Figure 2 shows the evaluation of temperature in the depth direction by computer simulation.

That is, when the laser beam is irradiated and the irradiation surface is constant at 1500°, heat conduction is conducted in the depth direction and the lateral direction as an error function. Furthermore, a simulation was performed assuming that laser light is absorbed according to the reciprocal of the light absorption coefficient. As a result, at a wavelength of 249 nm (KrF laser oscillation light), the absorption coefficient is 1. Since it has O2X106cm-',
A curve (11) is obtained. At 530 nm, the absorption number is 8.
．． 0OX10'cm-', we obtain curve (12). However, at a wavelength of 1.06μ, the absorption coefficient is 7X
10'cm-', the curve becomes vA(13), and when the irradiation light reaches the underlying semiconductor (amorphous silicon), the light arrives without being absorbed inside.

As a result, it was found that when the wavelength is 400 nm or more, the irradiation light damages semiconductors even at a depth of 0.2 μm or more. That is, it can be seen that when using a YAG laser beam having a wavelength of 1.06μ, the result is shown in FIG. 1(B), and scribing is performed by mixing the back electrode and the semiconductor. In addition, it is presumed that because the pulse width of the pulsed light was as long as 100 ns, which was not enough to increase the temperature, heat propagated to the peripheral area, causing a bulge in the peripheral area.

On the other hand, when using the excimer laser of the method of the present invention, the pulsed light is as short as 20ns (in the case of ArF), which is less than 50ns, so this pulsed light is sufficiently absorbed very close to the surface of the underlying semiconductor, causing damage inside the semiconductor. Since no light is added and the pulse width is short thermally, it cannot propagate.

As a result, it is presumed that only the back electrode on the upper side of the semiconductor could be selectively removed as shown in FIG. 1(B).

Also, as is clear from the table, the irradiation light is a function of the metal thickness. Therefore, it goes without saying that if the thickness of ITO/AI is to be increased according to the temperature and volume of the device, the required number of repeated pulses can be increased (and the optimum patterning depth can be adjusted). do not have.

When the absorption coefficient becomes even shorter, Fz (157 nm), A
It goes without saying that the selective processability can be further improved by using rF (193 nm) or KrF (222 nm). Although the absorption coefficient is lower, XeC1 (308 nm)
, XeF (350 nm) also showed selectivity, although damage to the underlying silicon semiconductor could not be completely prevented. The name takes into account the lifespan of the quartz lens, and the wavelength is 200n-
It is preferable to select it in the range of ~350 nm.

r Example 21 Details of a photoelectric conversion device using the present invention are shown below according to FIG.

FIG. 3 is a longitudinal sectional view showing the manufacturing process of the present invention.

In the drawings, a substrate (1) having a light-transmitting property and an insulating surface, such as glass or a light-transmitting organic film, such as PES
Alternatively, PET was used. Here, the glass substrate is 10cm
Integration was performed using X 10cn+ in an area of 10 cm x 3 cm.

On this substrate, a transparent conductive film having a tin oxide doped with fluorine on the upper surface was formed to a thickness of 500 to 3,000 layers by a known electron beam evaporation method or sputtering method.

After this, a YAG laser processing machine (Nippon Denki type) is applied to the upper side of this substrate with an average output of 0.3 to 3! A (focal length 4
0 mm), a spot diameter of 20 to 70 μΦ, typically 40 μΦ, is controlled by a microcomputer, and a laser beam is irradiated from above, and the scanning forms the first groove (14) for the scribe line. Inter-element area (3
1) The first electrode (37) was produced in (32).

Open groove (1) formed by laser patterning (LP)
4) had a width of approximately 50 μm and a length of 3 cm, and was cut and separated to a depth such that there was no CTF residue in the open groove portion to ensure complete isolation between the first electrodes. Thus, the width of the regions constituting the first element (31) and the second element (32) was formed to be 5 to 40 mm+for example, 8.3 mm.

Thereafter, a non-single crystal semiconductor, typically a non-single crystal semiconductor doped with hydrogen or a halogen element and having a PN or PIN junction, is formed on the upper surface by plasma CVD, photo CVD or LPCVD, which generates photovoltaic force by light irradiation. The single crystal semiconductor layer (3) is 0.3 to 1.0 μ, typically 0.7
It was formed to a thickness of μ.

A typical example is P type (stxc+-x O<x<
1) Semiconductor (approximately 200 people) - Type I amorphous or semi-amorphous silicon semiconductor (approximately 0.7μ) -N
Semiconductor with microcrystals of type (approximately 400 grain size) (approximately 80
A non-single-crystal semiconductor with one PIN junction consisting of 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 200 people) - P type 5ixC+ -x (about 50 people x=
0.2-0.3) It is a semiconductor.

Such a non-single crystal semiconductor (3) was formed to have a uniform thickness over the entire surface.

Furthermore, as shown in FIG. 3(B), the first open groove (1
A second open groove (15) was formed across the left side (first element side) of 4) by a second LP process (using a wavelength double the wavelength of YAG of 0.53 μm).

The second open groove (15) thus exposed the top surface of the first electrode.

This second open groove does not cut both ends of the semiconductor.
A portion of the semiconductor may be connected to each other in two regions as one or more openings.

Furthermore, CTP was formed on the upper surfaces of these by electron beam evaporation or sputtering to a thickness of 500 to 1,500, for example, 1,050. Here, ITO (15) was formed by electron beam evaporation. And this ITO and connector (30
), the contact resistance becomes an oxide-oxide contact (tin oxide-ITO contact) and no insulator barrier (insulator) is formed at the interface, resulting in abnormalities such as increased contact resistance during long-term use. It was practically preferable.

Furthermore, as shown in FIG. 3(C), this C
An aluminum film (25) was formed on the TF surface.

After that, the third LP is cut and separated by patterning using an excimer laser in the same manner as in Example 1, and a plurality of second LPs are formed.
The electrodes (39) and (38) were isolated and formed to obtain a third open groove (6).

This second conductive film (5) is a transparent conductive film (CTF) (
15) and aluminum (25) was used.

As this CTF, ITO (a mixture whose main components are indium oxide and tin oxide) (15) which makes good ohmic contact with the N-type semiconductor is formed to a thickness of 300 to 1500 mm. When the CTF is brought into close contact with a P-type semiconductor, it is also effective to form the CTF with tin oxide as the main component. As a result, the second electrode (1
5), (25) was provided.

This aluminum is not only pure aluminum but also IT
A thin silver film may be interposed between O and aluminum. In addition, a metal film (25) of aluminum alloy to which 0.1 to 50% by weight of copper, silver, and chromium are added is made by 300 to 0.0% by weight.
It may be formed to a thickness of 5 μm.

Furthermore, the depth of this third trench is such that in two-layer conductive films of CTP and aluminum, it is possible to avoid damaging the non-single crystal semiconductor in any way or near the upper surface of the semiconductor.
It was possible to form open grooves by removal alone at depths up to 500 mm).

Thus, as shown in FIG. 3(C), a plurality of elements (
31) and (32) were connected in series at the connecting part (4).

FIG. 3(D) shows an attempt to further complete the present invention as a photoelectric conversion device. That is, as a passivation film, a silicon nitride film (21) is uniformly formed to a thickness of 500 to 2,000 layers by plasma vapor phase method, energetic phase method, or photo plasma vapor phase method, and the leakage current between each element is absorbed. This further prevented the occurrence of such substances due to adsorption.

Furthermore, external lead-out terminals (22) and (22') were provided at the periphery. Thus, for the irradiation light (10), each element was provided in a strip shape with a width of 8.3111 m x 24 mm on a substrate (10 cm x 3c+++) as in this example, and the width of the connection part was 150 μm, and the width of the external lead electrode part was Width 3mm, peripheral part 3III, substantially 1
It had 11 stages within 100 nu x 30 mm, and was able to obtain an effective area (8.3 mm x 24 mm, 11 stages, 7.6%).

Furthermore, this panel, for example, 40cm x 120cm
Or, package it by combining one or four pieces of 60cm x 20cm in series within a hard frame made of aluminum sash or a flexible frame made of carbon black.
It is possible to provide a 120 cm x 40 cm NEDO standard high power panel.

In addition, for this NEDO standard panel, the top surface of the photoelectric conversion device of the present invention is attached to the back surface of the glass substrate (opposite side to the irradiation surface) using Seaflex to increase mechanical strength against wind pressure, rain, etc. is also valid.

"Effect" In the present invention, excimer laser light is used to produce laser light with a wavelength of 400 nm or less (preferably 200 to 350 nm).
In particular, by shortening the pulse width to 50 ns or less, preferably 30 ns or less, and by making the laser beam linear, the upper electrode coating can be selected without causing little or no damage to the underlying semiconductor. was able to be removed. This made linear patterning of photoelectric conversion devices possible for the first time.

In particular, this LP made it possible to pattern strongly oxidizing metals such as aluminum even in the atmosphere.

Therefore, it is possible to suppress the increase in manufacturing cost caused by manufacturing the substrate in vacuum or in an active gas atmosphere. Of course, doing it in a vacuum is effective to encourage partial pressure of the metal and save energy added to other pulses.

In addition, the excimer light is passed through a cylindrical lens with a width of 10 μm.
By condensing the light to ~300μ, the irradiation energy density can be increased, making it easier to process, and also making it possible to reduce the area of the inert connecting portion in the photoelectric conversion device. For this reason, it is more effective to make the width of the pattern 50μ narrower than 300μ, and 10μ narrower than 50μ.

In the present invention, a photoelectric conversion device is shown as a semiconductor device. However, the electrode of the present invention is effective when a light emitting element, a photosensor, an image sensor, an insulated gate field effect semiconductor device, etc. has a semiconductor as an underlying layer, and a conductive film for the electrode is laser patterned on the upper side of the semiconductor.

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal cross-sectional view of a light-transmitting film on a semiconductor according to the present invention processed by laser. FIG. 2 shows the results of computer simulation. FIG. 3 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of the present invention.

Claims (1)

[Claims] 1. A conductive film consisting of a transparent conductive film and a metal on the film is formed on a semiconductor surface, and the conductive film is irradiated with pulsed laser light with a wavelength of 400 nm or less. A method for manufacturing a semiconductor device characterized by dividing it into a plurality of regions. 2. Forming a transparent conductive film on a substrate having an insulating surface, irradiating the first conductive film with a laser beam to form a first groove, and forming a plurality of first conductive films. a step of forming a plurality of first electrodes by dividing into a predetermined shape; a step of forming a non-single crystal semiconductor that generates a photovoltaic force by light irradiation on the electrode and the groove; a step of forming a second trench or hole by irradiating a laser beam; a transparent conductive film on the semiconductor and the second trench and on the semiconductor; and a metal conductive film on the film. a step of forming a second conductive film by
A semiconductor device for photoelectric conversion having a plurality of second electrodes is manufactured by forming a third groove in the second conductive film by irradiating pulsed laser light of nm or less. Semiconductor device manufacturing method. 3. In claim 1 or 2, 40
1. A method for manufacturing a semiconductor device, characterized in that the laser beam having a wavelength of 0 nm or less has a pulse width of 50 ns or less and is an excimer laser beam that can be irradiated in a linear manner. 4. In claim 1 or 2, 40
A semiconductor characterized in that the transparent conductive film on the semiconductor and the metal thereon are removed without damaging the semiconductor or removing the semiconductor by irradiation with laser light having a wavelength of 0 nm or less. How to create the device. 5. A method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the semiconductor device is made of aluminum or aluminum as a main component.