JPH0799335A - Removal and processing of semiconductor film and manufacture of photovoltaic element - Google Patents

Abstract

PURPOSE:To remove a semiconductor film only without unfavorably affecting an underneath layer by a method wherein the processed part of semiconductor film is irradiated with the first beams and then further irradiated with the second beams having the different energy density from that of the first energy beams. CONSTITUTION:A metallic film 2 is provided on a substrate 1 and then a semiconductor film 3 comprising amorphous silicon is provided on the metallic film 2. Next, this semiconductor film 3 is irradiated with the first beams 4 having a specific energy density. At this time, the irradiated region of the semiconductor film 3 is fine crystallized by the irradiation with the laser beams 4 to impose the stress due to the fluctuation in the lattice constant for causing release from the metallic film 2 as the underneath layer. Next, the irradiated region 3a making a fine gap with the metallic film 2 is further irradiated with the second laser beams 5 having another specific energy density. Through these procedures, the irradiated region 3a can be removed by the irradiation with the second laser beams 5 thereby enabling the removed part 3b to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing and processing at least a part of a semiconductor film, and more particularly to a method for removing and processing a semiconductor film by irradiating an energy beam such as a laser beam and the removal processing. The present invention relates to a method for manufacturing a photovoltaic element using the method.

[0002]

2. Description of the Related Art In a process of manufacturing a semiconductor device such as a photovoltaic element, a part of a semiconductor film is irradiated with an energy beam such as a laser beam to remove a fine region. In the removal processing by irradiation with such an energy beam, the removal processing is performed by irradiation with a beam having an energy density equal to or higher than the binding energy of the constituent components of the semiconductor film. The semiconductor film can be removed into a predetermined pattern by scanning with a spot-shaped energy beam or by using a line-shaped energy beam.

[0003]

In a semiconductor device such as a photovoltaic element, a semiconductor film may be formed on a metal film, and such a semiconductor film is removed by irradiation with an energy beam such as a laser beam. In the case of processing, there were the following problems.

That is, in the removal processing by energy beam irradiation, there is a threshold value for the energy density, and the threshold value of the semiconductor film is higher than the threshold value of the metal film. Therefore, when the semiconductor film formed on the metal film is irradiated with an energy beam below the threshold of the semiconductor film,
There is a problem in that the semiconductor film cannot be removed and processed, and when the energy beam having an energy density equal to or higher than the threshold value of the semiconductor film is irradiated, the metal film as the base layer is simultaneously removed and processed.

An object of the present invention is to provide a method capable of removing only a semiconductor film without adversely affecting an underlayer and a method of manufacturing a photovoltaic element using the removing processing method. .

[0006]

According to a method for removing and processing a semiconductor film of the present invention, after a portion to be processed of a semiconductor film is irradiated with a first energy beam, a first energy beam having an energy density different from that of the first energy beam is irradiated. It is characterized by irradiating two energy beams.

According to a first aspect of the present invention, a step of irradiating a processed portion of a semiconductor film with a first energy beam to distort a region of the processed portion, and a step of distorting the processed portion to the processed portion are performed. And the step of irradiating the processed portion with two energy beams.

[0008]

In the present invention, the processed portion of the semiconductor film is removed by irradiating the processed portion with the energy beam a plurality of times. The semiconductor film to be the subject of the present invention is not particularly limited, but examples thereof include semiconductors such as silicon and compound semiconductors such as GaAs. Examples of crystal forms include amorphous, microcrystalline, polycrystalline and A single crystal semiconductor film can be used. In particular, the amorphous semiconductor film can be microcrystallized by irradiation with an energy beam and can give a large strain to a region to be processed, so that the present invention can be preferably used. In addition, the film thickness of the semiconductor film removed by laser beam irradiation is generally about 0.1 to 1000 μm.

In the first aspect according to the present invention, a predetermined region of the semiconductor film is removed and processed by irradiating the energy beam at least twice, and the region of the processed portion is thermally processed by the first energy beam irradiation. The portion to be processed is removed by applying the second energy beam with distortion.

The operation of the present invention will be described with reference to FIG. With reference to FIG. 1A, a metal film 2 is provided on a substrate 1, and a semiconductor film 3 made of amorphous silicon is provided on the metal film 2. For this semiconductor film 3, FIG.
As shown in (b), the first laser beam 4 having a predetermined energy density is irradiated. By the irradiation of the laser beam 4, the irradiated region of the semiconductor film 3 is microcrystallized, and stress is generated due to the change of the lattice constant, so that the semiconductor film 3 is separated from the metal film as the underlayer as shown in FIG. 1B. Is supposed to occur. The irradiated region 3a in which a fine space is formed between the metal film 2 and the metal film 2 is irradiated with a second laser beam having a predetermined energy density as shown in FIG. The irradiation area is removed by this laser beam irradiation, and the removed portion 3b is formed as shown in FIG. 1 (c).

As described above, according to the present invention, the first energy beam irradiation imparts a strain, which reduces the adhesiveness with the metal film as the underlayer in some form, and the adhesiveness is reduced. Since the second energy beam irradiation is applied to the irradiated region, it is possible to remove only the semiconductor film without damaging the metal film that is the base layer.

In the first aspect of the present invention, the energy density of the energy beam for irradiation can be appropriately selected in consideration of the material, thickness, etc. of the target semiconductor film. Further, the energy density is selected depending on whether it is the first energy beam irradiation for giving the distortion or the second energy beam irradiation for removing and processing the portion to be processed. When removing and processing an amorphous silicon thin film having a film thickness of about 0.1 to 1000 μm, the energy density of irradiation of the first energy beam that gives strain is 0.01.
˜1.0 J / cm ² is preferable, and more preferably 0.
It is 05 to 0.5 J / cm ² . Second for removal processing
The energy density of the energy beam irradiation is 0.
1 to 10 J / cm ² is preferable, and more preferably 0.
It is 5 to ² J / cm ² . In general, the energy density of the second energy beam is higher than the energy density of the first energy beam, but the same energy density may be used if necessary, or the first energy beam may be set higher. You can also

The wavelength of the energy beam is 0.
The wavelength is generally 5 μm or less, and when a laser is used as a beam source, the wavelength is generally 0.19 to 0.35 μm.

The method of manufacturing a photovoltaic element according to the present invention is a method of manufacturing a photovoltaic element in which a partially removed metal film and a semiconductor film are stacked above a substrate. A step of forming a film, a step of irradiating the processed portion of the metal film with the first energy beam and then a second energy beam to remove the processed portion, and a step of removing the processed metal film. Forming a semiconductor film on the semiconductor film, and irradiating the processed portion of the semiconductor film with the first energy beam,
And irradiating a second energy beam having an energy density different from that of the above energy beam to remove the processed portion.

In the above-mentioned metal film removing processing method, after the first energy beam is irradiated to the processed portion of the metal film,
Irradiation with a second energy beam having an energy density different from that of the first energy beam, or a narrower area within the irradiation area of the first energy beam, or a wider area including the irradiation area of the first energy beam , A second energy beam is emitted. If the irradiation area of the second energy beam is narrower or wider than the irradiation area of the first energy beam, the first energy beam and the second energy beam may have the same energy density or different energy densities. Yes.

In the first embodiment of the metal film removal processing, the step of irradiating the processed portion of the metal film with the first energy beam to change the quality of the metal film in the region of the processed portion, and And the step of irradiating the processed part by irradiating the second energy beam.

In the first embodiment, the first energy beam of low energy that does not cause the removal of the metal film is applied. As a result, heat treatment such as annealing and quenching is performed, and modification is performed so that deformation during removal processing is less likely to occur. After modifying the metal film in this way, a higher energy beam is irradiated to remove the processed portion. The area of such removal processing is an area inside the irradiation area of the first energy beam,
The second energy beam is irradiated in such an area,
Removal processing is performed. Since the removing process is performed in the region of the metal film that has already been modified, the deformed portion such as the protrusion is less likely to occur.

In the first embodiment, the energy density of the first energy beam is preferably 0.01 to.
0.5 J / cm ² , more preferably 0.05
Is about 0.2 J / cm ² . The energy density of the second energy beam is preferably 0.2 to 1.5 J.
/ Cm ² , more preferably 0.2 to 1 J / c
m ² .

In the first embodiment, when the irradiation area of the second energy beam is narrower than the irradiation area of the first energy beam, the energy densities of the first energy beam and the second energy beam are different. They may be the same or substantially the same.

In the second embodiment of the metal film removal processing, the step of irradiating the processed portion of the metal film with the first energy beam to remove the processed portion, and the second region in the peripheral region of the processed portion. Irradiating with an energy beam to flatten the deformed portion of the peripheral region.

In the second embodiment, by irradiating the first energy beam, the metal film is removed and processed as in the conventional case. Next, by irradiating the deformed portion of the peripheral region of the removed portion formed by the irradiation of the first energy beam or a wider region including the first energy beam irradiation region with the second energy beam and melting the deformed portion, It is flattened.

In the second embodiment, the first energy
The energy density of the beam is preferably 0.2 to
1.5 J / cm²And more preferably 0.2 to
1 J / cm²Is. The second energy beam
The energy density is preferably 0.1 to 0.9 J / cm.
²And more preferably 0.3 to 0.6 J / cm.
²Is.

In the second embodiment, when the irradiation area of the second energy beam is wider than the irradiation area of the first energy beam, even if the energy densities of the first energy beam and the second energy beam are different from each other. Good or substantially the same.

According to the above-described metal film removal processing method, since the deformed portion such as the protrusion does not remain in the peripheral region of the removal processed portion after the removal processing, even if a semiconductor thin film or the like is formed on the metal film, the semiconductor thin film There is no problem such as peeling, pinhole, or electric leak.

In the semiconductor film removal processing step in the manufacturing process of the present invention, the step of the first aspect of the semiconductor film removal processing method of the present invention can be used. The energy density of the energy beam irradiated in the present invention can be appropriately selected in consideration of the material and thickness of the target metal film and semiconductor film.

According to the method of manufacturing a photovoltaic element of the present invention, the metal film can be removed without leaving a deformed portion such as a protrusion, so that the semiconductor film formed on the metal film can be peeled off, pinholes, In addition, it is possible to reduce the occurrence of electrical leakage and the like, and at the time of removing and processing the semiconductor film, without adversely affecting the metal film as the base layer,
Only the semiconductor film can be removed.

[0027]

EXAMPLE A metal film (thickness 2000
Å) was formed, and the amorphous silicon thin film (thickness 6000 Å) formed on this metal film was irradiated with a laser beam using a XeCl excimer laser for removal processing.

Example 1 An energy beam was applied twice to a work piece according to the present invention. The energy density of the first laser beam is 0.2
And 28 J / cm ^2, the energy density of the second time of the laser beam was 0.446J / cm ^2. The surface condition after each laser beam irradiation was observed with a microscope. The results are shown in Table 1. The results of observation with a microscope are shown in FIG.

[0029]

[Table 1]

Comparative Examples 1 to 4 As a comparison, the amorphous silicon thin film was irradiated with the laser beam only once by changing the energy density of the laser beam. The surface condition after laser beam irradiation was observed with a microscope. The results are shown in Table 2. In Tables 1 and 2, a-Si represents an amorphous silicon thin film. The results of observation with a microscope are shown in FIG.

[0031]

[Table 2]

As is clear from Table 1 and FIG. 8, when the first laser beam irradiation distorts the amorphous silicon thin film by the second laser beam irradiation according to the present invention, it is an underlayer. The amorphous silicon thin film can be removed without damaging the metal film. As is clear from Table 2 and FIG. 9, it is difficult to adjust the energy density and remove only the amorphous silicon thin film by irradiating the laser beam only once, and the amorphous silicon thin film remains. Or a crack or the like may occur in the metal film of the underlayer.

Next, an example of a method of manufacturing a photovoltaic element according to the present invention will be described. Referring to FIG. 2, Si is formed on a substrate 11 made of glass or SUS stainless steel.
Inorganic materials such as O ₂ and Al ₂ O ₃ or polyimide, PM
An insulating film 12 made of an organic material such as MA or acrylic is formed, and a metal film 13 made of Al, Ag, ITO, W or a combination thereof is formed on the insulating film 12. With reference to FIG. 3, the metal film 13 is linearly removed at predetermined intervals to form a removed portion 13a, and the metal film 13 is divided into a plurality of parts.

The removal processing of the metal film 13 can be performed by laser irradiation. FIG. 10: is a figure which shows the method according to the 1st embodiment of the said metal removal process. Figure 10
Referring to (a), the metal film 13 is irradiated with a laser beam 24 having an energy density of 0.10 J / cm ² , for example. The laser beam 24 is emitted by using a XeCl excimer laser.

Referring to FIG. 10B, the modified region 13b is formed in the irradiated region of the metal film 13 by the irradiation of the laser beam 24. The modified region 13b is a part modified by annealing or quenching with the laser beam 24. Next, a laser beam 25 having an energy density of 0.90 J / cm ² is applied to the region inside the modified region 13b. Laser beam 25
Is also irradiated using a XeCl excimer laser.

Referring to FIG. 10C, the metal film in the modified region 13b is removed by the irradiation of the laser beam 25, and the removed portion 13a is formed.

Further, the removal processing of the metal film may be performed by the method according to the second embodiment. FIG. 11 is a sectional view for explaining such a method. FIG. 11 (a)
Referring to, the region of the metal film 13 to be removed is irradiated with the laser beam 24 as the first energy beam. As the laser beam 24, a laser beam of YAG laser is used, and the energy density is 0.03 to 1 J /
cm ² In this embodiment, it is set to 0.3 J / cm ² .

Referring to FIG. 11B, the removed portion 13a is formed on the metal film 13 by the irradiation of the laser beam 24. Further, in the peripheral region of the removed portion 13a, the metal film 13 rises to form a deformed portion 13c. Deformed part 1
The height of 3c was 1.0 μm. Next, the deformed portion 13
A wider area including c is irradiated with the laser beam 25 from the YAG laser. The energy density of the laser beam 25 was 0.5 J / cm ² .

Referring to FIG. 11C, the deformed portion of the peripheral region of the removed portion 13a is flattened by the irradiation of the laser beam 25, and the flattened region 13d is formed. The flattened region 13d has a height of about 0.1 μm from the surface of the metal film 13.

As described above, according to the second embodiment, the degree of deformation of the deformed portion formed after the laser beam irradiation and removal can be reduced. Referring to FIG. 4, p is formed on the metal film 13 that has been removed and processed as described above.
An amorphous silicon thin film 14 having an n, pin, np, or nip junction is formed. Also, pnpnpn ..., p
inpinpin ..., npnpnp ..., or nip,
A multi-bandgap structure such as nip, nip ...

Referring to FIG. 5, the amorphous silicon thin film 14 is linearly irradiated with the first energy beam. As the first energy beam, for example, XeC
A laser beam of an excimer laser is used. The amorphous silicon thin film is strained by this first energy beam irradiation. Since the first energy beam irradiation gives a strain, the adhesion with the metal film 13 as the underlayer is lowered in some form. Then, the second energy beam is irradiated to the irradiation area where the adhesiveness is lowered. The amorphous silicon thin film 14 is removed by this second energy beam irradiation. In this way, the amorphous silicon thin film is removed after the first energy beam irradiation distorts the adhesiveness to the metal film to reduce the strain.
Damage to the metal film that is the underlayer is reduced. The energy density of the first energy beam used in such a semiconductor film removal processing step is, for example, 0.1.
It is generally about 1.0 J / cm ² . Further, the energy density of the second energy beam for removal processing is generally about 0.1 to 10 J / cm ² . In this embodiment, the first energy beam is 0.22.
A laser beam having an energy density of 8 J / cm ² was used. The second energy beam is 0.446.
A laser beam having an energy density of J / cm ² was used. As described above, the linear removal portion 14a is formed on the amorphous silicon thin film 14.

Next, referring to FIG. 6, ITO, Sn
A transparent conductive film 15 made of O ₂ , ZnO or the like is formed. Next, referring to FIG. 7, the transparent conductive film 15 is irradiated with a laser to be removed in a line shape and divided. Alternatively, the removed portion may be formed by patterning with a photoresist and etching. As described above, as shown in FIG.
It is possible to obtain a photovoltaic element in which units of divided photovoltaic elements are connected in series.

According to the manufacturing method of the above-described embodiment, the degree of deformation of the deformed portion such as the protrusion can be reduced during the division removal processing of the metal film, and the amorphous silicon formed on the metal film can be reduced. It is possible to prevent peeling of the thin film, occurrence of pinholes, and occurrence of electrical leakage. In addition, when the amorphous silicon thin film is divided and removed, it is possible to reduce damage to the metal film as the base layer.

In each of the above embodiments, a metal film made of Al, Ag or the like has been described as an example, but the present invention is not limited to these. Although an amorphous silicon thin film is shown as an example of the semiconductor film, it may be applied to a compound semiconductor such as GaAs, or a crystalline silicon thin film such as microcrystal, polycrystal, or single crystal. The semiconductor film also includes those having a multi-bandgap structure such as pinpinpin ... And nipnipnip.

In the present invention, the number of irradiations of the first energy beam irradiation and the second energy beam irradiation is not limited to once, but may be plural times.

[0046]

According to the removal processing method of the present invention, the portion to be processed of the semiconductor film is irradiated with the first energy beam to distort the region of the portion to be processed, and then the second energy beam is irradiated. The processed part is removed. According to the present invention, since the energy beam is applied after strain is applied to the processed portion of the semiconductor film and the adhesion with the underlayer is reduced, only the semiconductor film is affected without adversely affecting the underlayer. It can be removed.

According to the method for manufacturing a photovoltaic element of the present invention, the metal film can be removed without leaving a deformed portion such as a protrusion, so that the semiconductor film formed thereon can be peeled off, pinholes, In addition, it is possible to reduce the occurrence of electrical leakage and the like, and at the time of removing and processing the semiconductor film, without adversely affecting the metal film as the base layer,
Only the semiconductor film can be removed.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a removal processing method according to the present invention, in which (a) a state before irradiation with an energy beam, (b) a state after irradiation with a first energy beam,
(C) is sectional drawing which shows the state after a 2nd energy beam irradiation, respectively.

FIG. 2 is a cross-sectional view showing a state after forming a metal film in a manufacturing process of a photovoltaic element.

FIG. 3 is a cross-sectional view showing a state after a pattern is formed on the metal film in the manufacturing process of the photovoltaic element.

FIG. 4 is a cross-sectional view showing a state after an amorphous silicon thin film is formed in the manufacturing process of the photovoltaic element.

FIG. 5 is a cross-sectional view showing a state after the amorphous silicon thin film has been removed by the removal processing method according to the present invention in the manufacturing process of the photovoltaic element.

FIG. 6 is a cross-sectional view showing a state after a translucent conductive film is formed in the process of manufacturing the photovoltaic element.

FIG. 7 is a cross-sectional view showing a state after a pattern is formed on the translucent conductive film in the process of manufacturing the photovoltaic element.

FIG. 8 is a micrograph showing a surface state of a thin film after laser beam irradiation in an example according to the present invention.

FIG. 9 is a micrograph showing a surface state of a thin film after laser beam irradiation in a comparative example.

FIG. 10 is a cross-sectional view showing a first embodiment of a method of dividing a metal film by irradiating it with a laser beam and performing a removal process in the manufacturing process of the photovoltaic element.

FIG. 11 is a cross-sectional view showing a second embodiment of a method of dividing a metal film by irradiating it with a laser beam and removing the metal film in the manufacturing process of the photovoltaic element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Metal film 3 ... Semiconductor film 3a ... Energy beam irradiation part of semiconductor film 3b ... Semiconductor film removal part 4 ... First energy beam 5 for giving distortion to the processed part of semiconductor film 5 ... Second energy beam for removing the processed portion of the semiconductor film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Hosokawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (7)

[Claims] 1. A method of removing and processing at least a part of a semiconductor film by irradiating with an energy beam, the method comprising: irradiating a processed portion of the semiconductor film with a first energy beam; A method for removing and processing a semiconductor film, which comprises irradiating a second energy beam having an energy density different from that of the beam. 2. A method of removing and processing at least a part of a semiconductor film by irradiating with an energy beam, wherein the processed portion of the semiconductor film is irradiated with a first energy beam to a region of the processed portion. A method of removing and processing a semiconductor film, comprising: a step of applying a strain; and a step of irradiating the processed portion to which the distortion has been applied with a second energy beam to remove the processed portion. 3. The semiconductor film is an amorphous semiconductor film,
The method for removing and processing a semiconductor film according to claim 2. 4. The method for removing and processing a semiconductor film according to claim 1, wherein the wavelengths of the first energy beam and the second energy beam are 0.5 μm or less. 5. A method of manufacturing a photovoltaic device, wherein a partially removed metal film and a semiconductor film are stacked above a substrate, the method comprising forming the metal film above the substrate, Irradiating the processed portion of the metal film with the first energy beam and then irradiating the processed portion with the second energy beam; and removing the semiconductor film on the removed processed metal film. Forming step and irradiating the processed portion of the semiconductor film with the first energy beam, and then irradiating the processed portion of the semiconductor film with a second energy beam having an energy density different from that of the first energy beam to remove the processed portion And a method of manufacturing a photovoltaic element. 6. A method of manufacturing a photovoltaic element, wherein a partially removed metal film and a semiconductor film are stacked above a substrate, the step of forming the metal film above the substrate, After irradiating the processed portion of the metal film with the first energy beam, the second energy is applied to a narrower region within the first energy beam irradiation region or a wider region including the first energy beam irradiation region. A step of irradiating a beam to remove the processed portion, a step of forming the semiconductor film on the removed metal film, and a step of irradiating the processed portion of the semiconductor film with a first energy beam And a step of irradiating a second energy beam having an energy density different from that of the first energy beam to remove the processed portion, the method of manufacturing a photovoltaic element. 7. The step of removing the processed portion of the semiconductor film includes the step of irradiating the processed portion of the semiconductor film with a first energy beam to distort the region of the processed portion, and 7. The method for manufacturing a photovoltaic element according to claim 5, further comprising the step of irradiating a given portion to be processed with a second energy beam to remove the portion to be processed.