JP2000124488A - Manufacture of thin film solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacture method of a thin film solar battery with less shorting and leak by preventing the pile-up of a film and a melting drop at the time of dividing the film with the irradiation of a laser beam. SOLUTION: A lower electrode film 11 is formed on an insulating substrate 10 and the lower electrode film 11 is divided into strips with laser beams L1 from which the part of low energy is removed by slits. A semiconductor film 12 is formed on the lower electrode film 11 and the insulating substrate 10 exposed by the irradiation of the laser beams L1. A semiconductor film 12 is divided into the strips with laser beams L2 from which the part of low energy is removed by the slits. An upper electrode film 13 is formed on the semiconductor film 12 and the lower electrode film 11 exposed by the laser beams L2. The upper electrode film 13 is divided into strips with laser beams L3 from which the part of low energy is removed by the slits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin-film solar cell, and more particularly to a method for manufacturing an integrated thin-film solar cell in which two or more unit cells connected in series are formed on an insulating substrate.

[0002]

2. Description of the Related Art The widespread use of solar cells that directly convert solar energy into electrical energy has begun.
Crystalline (bulk) solar cells typified by single crystal silicon, polycrystalline silicon, and the like have already been put to practical use as outdoor power solar cells. On the other hand, thin-film solar cells using polycrystalline thin-film silicon, amorphous silicon, or chalcopyrite-structured semiconductors have attracted attention as low-cost solar cells because they require less material. Thin-film solar cells
Like a conventional thin film device, it is manufactured by repeatedly forming and patterning a thin film using a CVD method, an evaporation method, a sputtering method, or the like.

Referring to FIG. 1, a semiconductor film is a chalcopyrite-structured semiconductor thin film (compound semiconductor thin film made of an Ib group, IIIb and VIb group element, for example, CuInS
e ₂ (CIS) or Cu (In, G
a) The structure of an integrated thin-film solar cell using Se ₂ (CIGS) will be described. FIG. 1 is a sectional view of an integrated thin-film solar cell.

As shown in FIG. 1, unit cells 5a and 5b are formed on an insulating substrate 1 by lower electrode films 2a and 2b.
b, the semiconductor films 3a and 3b in which the CIS thin film and the CdS thin film are joined, and the upper electrode films 4a and 4b are included in this order. Lower electrode films 2a and 2b, semiconductor films 3a and 3
b and the upper electrode films 4a and 4b are divided by the grooves 2c, 3c or 4c, respectively. The upper electrode film 4b of the unit cell 5b and the lower electrode film 2a of the unit cell 5a are electrically connected through the groove 3c, so that adjacent unit cells are connected in series. In order to manufacture such an integrated thin-film solar cell, patterning for forming the grooves 2c, 3c and 4c is necessary.

Conventionally, a photolithography method has been used as a patterning method. A method of manufacturing the integrated thin-film solar cell shown in FIG. 1 using a photolithography method will be described below. First, a molybdenum (Mo) film, for example, is formed as a lower electrode film 2 on the insulating substrate 1 by a sputtering method, and then a resist is printed, exposed, and developed according to a pattern to be patterned. Then, the lower electrode film 2 is divided into strips by forming the grooves 2c by the etching method. After that, remove the resist,
After washing and drying, patterning of the lower electrode film is completed. Next, CuI is deposited by vapor deposition or sputtering.
An nSe ₂ thin film is formed, and Cd is deposited thereon by a chemical deposition method.
A semiconductor thin film 3 including a junction is formed by forming an S film, and then, resist printing is performed similarly to the lower electrode film 2.
The patterning of the semiconductor film 3 is completed by performing exposure, development, etching, washing and drying. Finally, a transparent conductive film, for example, a ZnO film or an ITO film is formed as the upper electrode film 4 by the sputtering method, and resist printing, exposure, development, etching, washing, and drying are performed in the same manner as the lower electrode film 2. The patterning of the film 4 is completed.

However, when the photolithography method is used, the number of steps is so large that it is not suitable for increasing the area. Therefore, in recent years, a laser scribe method has been used as a patterning method (13th European).
Photovoltaic Solar Confer
ence 1995 pp. 1451-1455). In the laser scribing method, the thin film is irradiated with a laser beam while moving the substrate on which the thin film is formed, thereby removing the thin film at the portion irradiated with the laser beam, and thereby performing patterning of the thin film.

[0007]

However, there are some problems when patterning is performed by the laser scribe method.

A laser beam conventionally used in the laser scribe method has an energy distribution in a direction perpendicular to an optical path.
As shown in FIG. 2A, the energy distribution was Gaussian with a high energy at the center and a low energy at the periphery. For this reason, as shown in FIG. 2B, there is a problem that the film is swelled at both ends of a groove formed in the film by irradiating the laser beam. This is because, of the film to be cut, a portion irradiated with a laser beam having a certain energy or more (the center of the laser beam) is removed, whereas a portion having a weak energy (the periphery of the laser beam) is removed. It is considered that the portion irradiated with (part) is not removed, but is melted and deformed. In the case of FIG. 2B, a semiconductor film or the like is formed and integrated thereafter.
As shown in FIG. 2C, the upper electrode film and the lower electrode film are short-circuited or leak in the same unit cell, which causes a decrease in yield and conversion efficiency of the solar cell. .

In addition, in the case of a conventional laser beam having a Gaussian distribution, as shown in FIG. 3, melting and dripping may occur and a groove may not be formed. In the case shown in FIG. 3, adjacent unit cells are short-circuited, which causes a decrease in yield and conversion efficiency of the solar cell.

Furthermore, the above problem occurs in any of the lower electrode film, the semiconductor film, and the upper electrode film.

An object of the present invention is to provide a method for manufacturing a thin-film solar cell in which short circuits and leaks are less likely to occur in order to solve the above-mentioned conventional problems.

[0012]

In order to achieve the above object, a first method of manufacturing a thin film solar cell according to the present invention is directed to a thin film solar cell comprising two or more unit cells connected in series on an insulating substrate. A method for manufacturing a solar cell, comprising: a first step of forming a lower electrode film on an insulating substrate; and a step of irradiating the lower electrode film with a first laser beam to divide the lower electrode film into strips. Step 2, the lower electrode film and the second
A third step of forming a semiconductor film on the insulating substrate exposed by the step, a fourth step of irradiating the semiconductor film with a second laser beam to divide the semiconductor film into strips, and a semiconductor film. A fifth step of forming an upper electrode film on the lower electrode film exposed in the fourth step;
A sixth step of dividing the upper electrode film into strips by irradiating the upper electrode film with a laser beam of
At least one of the laser beam, the second laser beam, and the third laser beam is a continuous wave laser beam from which low-energy light is removed by a slit.

In the first method of manufacturing a thin-film solar cell, the lower electrode film, the semiconductor film, or the upper electrode film is divided by irradiating a continuous oscillation laser beam from which low-energy light has been removed by slits. You. Therefore, according to this method, unlike the conventional laser scribing method using a laser beam having a Gaussian distribution type intensity distribution, swelling or dripping does not occur in the divided portion of the film, so that short-circuiting and leakage occur. Can be suppressed.

In the first method of manufacturing a thin-film solar cell, continuous oscillation in which low-energy light is removed by slits in each of the first laser beam, the second laser beam, and the third laser beam. It is preferable to use the laser beam because the occurrence of short circuit and leak can be further suppressed.

In the first method of manufacturing a thin film solar cell, the lower electrode film may be a metal film, the semiconductor film may include a chalcopyrite structure semiconductor, and the upper electrode film may be a transparent conductive film. This is preferable because the damage caused by an increase in temperature is minimized in the process of performing the above.

Next, a second method for manufacturing a thin film solar cell according to the present invention is a method for manufacturing a thin film solar cell in which two or more unit cells connected in series are formed on an insulating substrate. A first step of forming a lower electrode film on a substrate, a second step of irradiating the lower electrode film with a first laser beam to divide the lower electrode film into strips, A third step of forming a semiconductor film on the insulating substrate exposed by the step, a fourth step of irradiating the semiconductor film with a second laser beam to divide the semiconductor film into strips, and a semiconductor film. A fifth step of forming an upper electrode film on the lower electrode film exposed in the fourth step, and a sixth step of irradiating the upper electrode film with a third laser beam to divide the upper electrode film into strips. The first step Zabimu, at least one of the second laser beam or the third laser beam is characterized by a continuous wave laser beam energy distribution is converted so as to be substantially uniform by using optical means.

In the second method of manufacturing a thin-film solar cell according to the present invention, the continuous oscillation in which the lower electrode film, the semiconductor film, and the upper electrode film are converted by optical means so that the energy distribution becomes substantially uniform. Are divided by irradiating the laser beam. Therefore, according to this method, as in the method for manufacturing a thin film solar cell according to the first aspect, the occurrence of a short circuit or a leak can be suppressed.

In the second method for manufacturing a thin-film solar cell according to the present invention, the first laser beam, the second laser beam and the third laser beam have an energy distribution substantially equal to each other by using optical means. It is preferable to use a continuous wave laser beam converted so as to be uniform because the occurrence of a short circuit or a leak can be further suppressed.

According to a second method of manufacturing a thin film solar cell of the present invention, the lower electrode film is a metal film, the semiconductor film includes a chalcopyrite structure semiconductor, and the upper electrode film is a transparent conductive film. This is preferable because the damage caused by the increase in the temperature is minimized in the process of forming.

In the second method of manufacturing a thin-film solar cell according to the present invention, the optical means includes an aspherical type optical element, which adjusts the energy shape of the beam, prevents swelling due to processing of the film, It is preferable because a short circuit or a leak is prevented.

In the second method of manufacturing a thin-film solar cell according to the present invention, the optical means includes a diffractive optical element, whereby the energy shape of the beam is adjusted, the swelling due to the processing of the film is prevented, and It is preferred because it prevents leakage.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be specifically described with reference to examples.

In this embodiment, as an example, a compound semiconductor thin film (chalcopyrite structure semiconductor thin film) composed of a group Ib element, a group IIIb element and a group VIb element is used.
uInSe ₂ (CIS) or Cu with solid solution of Ga
A case where (In, Ga) Se ₂ (CIGS) is used for a semiconductor film as a light absorbing layer will be described.

(Embodiment 1) An example of a method of manufacturing a thin-film solar cell according to the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view illustrating a method for manufacturing a thin-film solar cell according to the present invention.

First, as shown in FIG. 4A, a lower electrode film 1 is formed on an insulating substrate 10 by, for example, a sputtering method.
Form one. The lower electrode film 11 is made of, for example, a metal such as molybdenum (Mo) and has a thickness of 0.5 μm to 2.0 μm.
μm.

Thereafter, as shown in FIG. 4B, the lower electrode film 11 is divided into strips for each unit cell by irradiating the lower electrode film 11 with a laser beam L1. The laser beam L1 irradiated at this time is a continuous oscillation laser beam from which low-energy light has been removed by the variable slit, and has a wavelength of, for example, 532 nm or 10 nm.
64 nm.

Thereafter, as shown in FIG. 4C, a semiconductor film 12 is formed so as to cover the lower electrode film 11 and the insulating substrate 10 exposed by the irradiation of the laser beam L1. The thickness of the semiconductor film 12 is, for example, 0.5 μm to 3 μm.
μm. The semiconductor film 12 is, for example, a laminate of a p-type semiconductor film and an n-type semiconductor film from the insulating substrate side. As the p-type semiconductor film, for example, CuInSe ₂
(CIS) film or Cu (In, G)
a) A chalcopyrite structure semiconductor film made of a Se ₂ (CIGS) film or the like is used, and is formed by a sputtering method, an evaporation method, or the like. As the n-type semiconductor film, for example, CdS, ZnO, Zn (O, OH), Zn (O, O
A compound containing at least a group II and group VI element such as H, S) is used, and is formed by a chemical deposition method or a sputtering method.

Thereafter, as shown in FIG. 4D, the semiconductor film 12 is irradiated with a laser beam L2 to divide the semiconductor film 12 into strips for each unit cell.
The laser beam L2 has a wavelength of, for example, 355 nm or 53 nm.
2 nm.

Thereafter, as shown in FIG. 4E, an upper electrode film 13 is formed so as to cover the semiconductor film 12 and the lower electrode film 11 exposed by the irradiation of the laser beam L2. The thickness of the upper electrode film 13 is, for example, 0.3 μm to
0.6 μm. The upper electrode film 13 is made of, for example, Zn
A transparent conductive film made of an O film, a ZnO: Al film, an ITO film, or the like, and is formed by a sputtering method or the like. The upper electrode film 13 is electrically connected to the lower electrode film 11 of an adjacent unit cell through a divided portion of the semiconductor film 12.

Thereafter, as shown in FIG. 4F, the upper electrode film 13 is irradiated with a laser beam L3,
The upper electrode film 13 is divided into strips for each unit cell. The wavelength of the laser beam L3 is, for example, 266 nm or 355 nm.

In this way, the unit cells 14, 15
And 16 are connected in series on the insulating substrate 10 to produce a thin-film solar cell.

With reference to FIG. 5, a method of irradiating the laser beams L1, L2 and L3 and an irradiation apparatus 20 in this embodiment will be described. The irradiation device 20 includes the laser oscillator 2
1, variable slit 22, adaptive optics 23, mirror 24,
The laser oscillator 21 includes a condenser lens 25 and a stage 26, and is, for example, an Nd: YAG laser. The laser beam emitted from the laser oscillator 21 is
After the low-energy light is removed in step 2, the compensating optical system 2
Enter 3. In the adaptive optics system 23, the laser beam is once expanded by a beam expander or the like so that the laser beam can be easily narrowed by the condenser lens 25. The expanded laser beam is reflected by the mirror 24 and condensed by the condensing lens 25 to be a laser beam L1, L2 or L3. The lower electrode film 11 formed on the insulating substrate 10 fixed to the stage 26 is irradiated with the laser beam L1, L2, or L3. The lower electrode film 11 and the like can be patterned by moving the stage 26 while irradiating the laser beams L1, L2, or L3.

Although FIG. 5 shows an example of the laser beam irradiation device, the configuration of the irradiation device is not limited to that shown in FIG. For example, FIG. 5 shows an example in which the variable slit 22 is arranged beside the laser oscillator 21, but the variable slit 22 may be arranged at another position on the optical path of the laser beam. The variable slit 22 need not be variable, but is preferably variable because the range of light to be removed can be controlled according to the beam profile of the laser beam.

FIG. 6 schematically shows the energy distribution of the laser beams L1, L2 and L3. Laser beam L
At 1, L2, and L3, light in the peripheral portion having low energy is removed by the variable slit 22, so that the lower electrode film 11 and the like are irradiated only with a laser beam having energy equal to or higher than a certain threshold. Therefore, there is little occurrence of bulging of the film or melting and dripping at both ends of the patterning groove formed by the irradiation of the laser beams L1, L2 and L3, and furthermore, without damaging the film in the lower part. The lower electrode film 11 and the like can be patterned.

In the above embodiment, the laser beam L
1, the case where all of L2 and L3 are irradiated by the irradiation device 20 is shown. However, by irradiating at least one of the laser beams L1, L2 and L3 by the irradiation device 20, compared with the case where the conventional manufacturing method is used. This can also prevent the occurrence of a short circuit or a leak (the same applies to the embodiments described below).

(Embodiment 2) Another example of a method of manufacturing a thin film solar cell using the present invention will be described. The second embodiment is different from the first embodiment shown in FIG. 4 only in the laser beams L1, L2 and L3 to be irradiated.
Duplicate description will be omitted.

Referring to FIG. 7, a method of irradiating laser beams L1, L2 and L3 and an irradiation device 30 in this embodiment will be described. The irradiation device 30 includes a laser oscillator 31, an optical element 32, a mirror 33, a condenser lens 34, and a stage 35. The laser oscillator 31 is, for example, an Nd: YAG laser. The energy distribution of the laser beam emitted from the laser oscillator 31 has a Gaussian distribution type at the time of emission, but is converted by the optical element 32 into a substantially uniform energy distribution. afterwards,
The laser beam is reflected by the mirror 33,
And become laser beams L1, L2 or L3. The laser beams L1, L2 and L3 are transmitted to the stage 3
Irradiation is performed on the lower electrode 11 and the like on the insulating substrate 10 fixed to 5. By moving the stage 35 while irradiating the laser beam, the lower electrode film 11 and the like can be patterned.

Although FIG. 7 shows an example of the irradiation device, the configuration of the irradiation device is not limited to that shown in FIG. As the optical element 32 for making the energy distribution of the laser beam substantially uniform, for example, an aspheric optical element such as an aspheric lens can be used. As shown in FIG. 8, when an aspheric lens is used as the optical element 32, an incident beam having a Gaussian energy distribution passes through the aspheric lens, so that a portion having a high energy intensity is diffused, and an energy intensity is diffused. The weak spots are focused. Therefore, the laser beam that has passed through the aspheric lens is converted into a laser beam having a substantially uniform intensity distribution.

According to the method for manufacturing a thin-film solar cell described in the above embodiment, the energy distribution of the laser beam applied when performing laser patterning is substantially uniform.
At both ends of the patterning groove formed by the irradiation of the laser beam L1, L2 or L3, there is little occurrence of film bulging or melting and dripping, and further, without damaging the underlying film, Electrode film 1
1 and the like can be patterned.

(Embodiment 3) Another example of a method of manufacturing a thin film solar cell using the present invention will be described. The third embodiment is different from the first embodiment shown in FIG. 4 only in the laser beams L1, L2, and L3 to be irradiated, and a duplicate description will be omitted.

Referring to FIG. 9, a method of irradiating laser beams L1, L2 and L3 and an irradiation device 40 in this embodiment will be described. The irradiation device 40 includes a laser oscillator 41, an optical element 42, a slit 43, and a condenser lens 44.
And a stage 45, and the laser oscillator 41 is, for example, an Nd: YAG laser. The energy distribution of the laser beam emitted from the laser oscillator 41 is of a Gaussian distribution type at the time of emission, but is converted by the optical element 42 into a substantially uniform energy distribution. After that, the laser beam passes through the slit 43 and is condensed by the condenser lens 44 to be a laser beam L1, L2 or L3. The lower electrode 11 on the insulating substrate 10 fixed to the stage 45 is irradiated with the laser beam L1, L2 or L3. While irradiating the laser beam, the stage 45
Is moved, the lower electrode film 11 and the like can be patterned.

Although FIG. 9 shows an example of the irradiation device, the configuration of the irradiation device is not limited to that shown in FIG. For example, a configuration without the slit 43 may be employed.

As the optical element 42 for making the energy distribution of the laser beam substantially uniform, for example, a diffractive optical element can be used.

As shown in FIG. 10, the diffractive optical element 50
Are, for example, microlens arrays 51 and 52
And a condenser lens 53. The diffractive optical element 50 can control the phase itself of the laser beam by controlling the surface shapes of the microlens arrays 51 and 52, and can convert the energy distribution of the laser beam substantially uniformly. FIG. 11 shows the laser beam L
1 schematically shows the energy distribution of L2 and L3.

According to the method of manufacturing a thin-film solar cell described in the above embodiment, the energy distribution of the laser beam irradiated when performing laser patterning is substantially uniform.
At both ends of the patterning groove formed by the irradiation of the laser beam L1, L2 or L3, there is little occurrence of film bulging or melting and dripping, and further, without damaging the underlying film, Electrode film 1
1 and the like can be patterned.

(Examples) In the case where the conventional method of manufacturing a thin-film solar cell is used and the case where the method of manufacturing a thin-film solar cell of the present invention is used, the results of actually manufacturing a thin-film solar cell will be described with reference to an example. I do.

A thin-film solar cell was manufactured using the method of Embodiment 1, the method of Embodiment 2, and a conventional laser patterning method. In the manufactured thin-film solar cell, the lower electrode film was a Mo film having a thickness of 1 μm, and the semiconductor film was Cu (I) having a solid solution of Ga.
a 2 μm-thick semiconductor film in which an (n, Ga) Se ₂ (CIGS) film and a compound containing Group II and Group VI elements are joined;
The upper electrode film is a ZnO or ITO film having a thickness of 0.5 μm, and the cell area is 2 cm ² .

The cell characteristics of thin-film solar cells manufactured using the method of Embodiment 1, the method of Embodiment 2, and the conventional laser patterning method were measured (AM 1.5, 100 mW).
/ Cm ² ).

The thin-film solar cell manufactured by the method of Embodiment 1 has an open-circuit voltage of 1.268 V, a short-circuit current of 34.28 mA,
With a fill factor of 0.63, the conversion efficiency was 13.69%. The thin-film solar cell manufactured by the method of Embodiment 2 had an open-circuit voltage of 1.262 V, a short-circuit current of 34.26 mA, a fill factor of 0.73, and a conversion efficiency of 15.78%. The thin-film solar cell manufactured by the conventional method has an open circuit voltage of 0.196.
V, the short-circuit current was 23.92 mA, the fill factor was 0.26, and the conversion efficiency was 0.61%.

When the cross section of the thin-film solar cell manufactured by the conventional method was examined, it was found that the processing groove had a large swelling and short-circuits occurred at a plurality of locations as shown in FIG. Therefore, it was found that short circuits and leaks can be prevented by using the method for manufacturing a thin film solar cell of the present invention.

Although the embodiments of the present invention have been described with reference to the examples, the present invention is not limited to the above embodiments, but can be applied to other embodiments based on the technical idea of the present invention. .

For example, in the above embodiment, the case where a chalcopyrite structure semiconductor is used as a part of the semiconductor film has been described. However, as a semiconductor film, polycrystalline thin film silicon, microcrystalline silicon, amorphous silicon, amorphous silicon, Silicon germanium or the like may be used.

In the above embodiment, an example of a thin film solar cell in which a metal film, a semiconductor film, and a transparent conductive film are formed in this order from the insulating substrate side has been described. Film and metal film in this order.
The present invention may be used.

[0054]

As described above, according to the method for manufacturing a thin-film solar cell of the present invention, it is possible to suppress the occurrence of swelling and melting of the film when the film is divided by laser beam irradiation. It is possible to provide a method for manufacturing a thin-film solar cell with less occurrence of short circuit and leak. Therefore, the present invention is extremely important for stably supplying a thin-film solar cell having high conversion efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a conventional thin-film solar cell module.

FIG. 2 is a schematic diagram showing the energy distribution of a conventionally used laser beam and the problem of a conventionally used method of manufacturing a thin-film solar cell.

FIG. 3 is a schematic view showing an electrode film divided by a laser beam conventionally used.

FIG. 4 is a sectional view showing an example of a method for manufacturing a thin-film solar cell according to the present invention.

FIG. 5 is a schematic diagram showing an example of a laser beam irradiation device.

FIG. 6 is a schematic diagram showing an energy distribution of a laser beam.

FIG. 7 is a sectional view showing another example of the laser beam irradiation device.

FIG. 8 is a schematic diagram showing the energy distribution of the laser beam.

FIG. 9 is a sectional view showing another example of the laser beam irradiation device.

FIG. 10 is a schematic diagram showing functions of the diffractive optical element.

FIG. 11 is a schematic diagram showing the energy distribution of the laser beam.

[Explanation of symbols]

 Reference Signs List 10 Insulating substrate 11 Lower electrode film 12 Semiconductor film 13 Upper electrode film 22 Variable slit 32, 42 Optical element 50 Diffractive optical element L1, L2, L3 Laser beam

Claims (8)

[Claims] 1. A method for manufacturing a thin-film solar cell in which two or more unit cells connected in series are formed on an insulating substrate, comprising: a first step of forming a lower electrode film on the insulating substrate; A second step of irradiating the lower electrode film with a first laser beam to divide the lower electrode film into strips; and forming the lower electrode film on the insulating substrate exposed by the second step. A third step of forming a semiconductor film; a fourth step of irradiating the semiconductor film with a second laser beam to divide the semiconductor film into strips; and a semiconductor film and the fourth step. A fifth step of forming an upper electrode film on the exposed lower electrode film, and a sixth step of dividing the upper electrode film into strips by applying a third laser beam to the upper electrode film. Including At least one of the first laser beam, the second laser beam, and the third laser beam is a continuous wave laser beam from which low-energy light has been removed by a slit. Battery manufacturing method. 2. The laser beam according to claim 1, wherein each of the first laser beam, the second laser beam, and the third laser beam is a continuous wave laser beam from which low-energy light is removed by a slit. 3. The method for producing a thin-film solar cell according to 1. 3. The thin-film solar cell according to claim 1, wherein the lower electrode film is a metal film, the semiconductor film includes a chalcopyrite structure semiconductor thin film, and the upper electrode film is a transparent conductive film. Method. 4. A method of manufacturing a thin-film solar cell in which two or more unit cells connected in series are formed on an insulating substrate, comprising: a first step of forming a lower electrode film on the insulating substrate; A second step of irradiating the lower electrode film with a first laser beam to divide the lower electrode film into strips; and forming the lower electrode film on the insulating substrate exposed by the second step. A third step of forming a semiconductor film; a fourth step of irradiating the semiconductor film with a second laser beam to divide the semiconductor film into strips; and a semiconductor film and the fourth step. A fifth step of forming an upper electrode film on the exposed lower electrode film, and a sixth step of dividing the upper electrode film into strips by applying a third laser beam to the upper electrode film. Including At least one of the first laser beam, the second laser beam, and the third laser beam is a continuous wave laser beam converted to have a substantially uniform energy distribution using optical means. A method for manufacturing a thin-film solar cell, comprising: 5. A continuous oscillation in which all of the first laser beam, the second laser beam, and the third laser beam are converted by an optical means so that an energy distribution becomes substantially uniform. The method for manufacturing a thin-film solar cell according to claim 4, wherein the laser beam is a laser beam. 6. The method according to claim 4, wherein the lower electrode film is a metal film, the semiconductor film includes a chalcopyrite structure semiconductor thin film, and the upper electrode film is a transparent conductive film. Method. 7. The method according to claim 4, wherein said optical means includes an aspherical optical element. 8. The method according to claim 4, wherein said optical means includes a diffractive optical element.