JPH10305375A - Laser processing apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the laser processing apparatus which enables to form a high precision pattern such as scribed groove and the like, and yet to prevent short-circuiting due to recrystallization of once vaporized thin film material. SOLUTION: The laser processing apparatus 1 is an apparatus for forming a pattern on a face 9a of a laminated layer to be treated, which is one face of pliable transparent and insulated base plate 9, by irradiating the laser light L to the layer 9a. The apparatus is provided with a stage 2 of transparent material with a convex curved face 2a and a laser head LH on the reverse side 2b of the stage 2. The laser and light L irradiates to the layer to be treated from the laser head LH and through the stage 2 and the transparent insulated plate 9, while the convex face 2a of the stage 2 is being touched to the other face 9b of the transparent insulated plate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laser processing apparatus and method. More specifically, the present invention relates to a laser processing apparatus and method suitable for pattern processing a film laminated on a flexible transparent insulating substrate.

[0002]

2. Description of the Related Art Recently, integrated thin-film solar cells as shown in FIG. 6 have been actively produced. In this integrated type thin film solar cell, a transparent electrode layer 11, an amorphous photoelectric conversion layer 12, and a back electrode layer 13 are provided on one side of a flexible transparent insulating substrate (for example, made of a fluorine resin or other polymer compound) 10. It has a plurality of unit cells having a stacked structure.
The amorphous photoelectric conversion layer 12 in each unit cell is N-type, I-type,
And a P-type amorphous silicon layer, and generate an electromotive force in response to sunlight. Adjacent unit cells are electrically connected in series, and the electromotive force obtained by adding the electromotive force of each unit cell becomes the output voltage as a whole.

When manufacturing such an integrated thin-film solar cell, pattern processing is performed to divide each of the thin-film layers 11, 12, and 13 laminated on the substrate into strips corresponding to individual unit cells. And each of the thin film layers 11, 12, 13
(Hereinafter referred to as “scribe grooves”). As a method of pattern processing, it is suitable for fine processing. Therefore, laser scribing processing that irradiates a thin film with a laser beam to evaporate a part of the thin film (not only sublimation of the material by local heating but also ablation by a shock wave ( Exfoliation) is widely adopted.

[0004] First, after a transparent electrode layer 11 is laminated on the back surface of a transparent insulating substrate 10, the transparent electrode layer 11 is irradiated with laser light to form a line on the surface of the transparent electrode layer 11 at a constant pitch. By scanning, a first scribe groove SL1 is formed at the scanned position. Thereby, the transparent electrode layer 11
Is divided into a plurality of strips so that the transparent electrode layers 11 are electrically insulated from each other. Next, the amorphous photoelectric conversion layer 12 is stacked thereon by, for example, plasma CVD (chemical vapor deposition). Then, the amorphous photoelectric conversion layer 12 is irradiated with a laser beam, and the surface of the amorphous photoelectric conversion layer 12 is scanned at the same pitch as the above-mentioned pitch, and the amorphous photoelectric conversion layer 12 is moved to a position not overlapping with the first scribe groove SL1. 2 scribe groove SL
Form 2 Thus, the amorphous photoelectric conversion layer 12 is divided into a plurality of strips, and each amorphous photoelectric conversion layer 12 is electrically insulated from each other. Next, after laminating the back electrode layer 13 thereon, the back electrode layer 13 is irradiated with a laser beam, and the surface of the back electrode layer 13 is scanned in a line at the same pitch as the above-mentioned pitch. 2 scribe groove S
A third scribe groove SL3 is formed at a position not overlapping with L2. Thereby, the back electrode layer 13 is divided into a plurality of
While electrically insulating each back electrode layer 13 from each other,
The back electrode layer 13 of a certain unit cell and the transparent electrode layer 11 of an adjacent unit cell immediately below the unit cell are electrically connected through the second scribe groove SL2.

As described above, when an integrated thin-film solar cell is manufactured by using the laser scribe method, the scribe groove can be formed relatively easily as compared with the case of using another pattern processing method, so that the manufacturing process is simplified. And production costs can be kept low. Further, according to the laser scribe method, fine processing with a scribe width of 100 μm or less can be performed, so that the contact area between the back electrode layer 13 and the transparent electrode layer 11 can be reduced. As a result,
The area of the amorphous photoelectric conversion layer 12 relatively increases, and the effective power generation area of the integrated thin-film solar cell can be increased.

[0006]

When performing pattern processing by the laser scribe method, it is necessary that the layer to be processed be located within the depth of focus of the laser beam in order to perform the processing satisfactorily. You.

However, when the flexible transparent insulating substrate 10 is used as described above, the substrate 10 easily bends,
Since the flatness is not good, there is a problem that the layers to be processed 11, 12 and 13 are out of the focal depth of the laser beam. As a result, the image is defocused, the laser power on the processing surface fluctuates, and the pattern cannot be formed with high accuracy. When a relatively rigid glass substrate is used as the transparent insulating substrate, the thickness variation and bending of the glass substrate can be controlled within desired specified values, and the flatness required for laser processing can be secured. Therefore, there is not much problem.

In order to solve the problem that the layer to be processed deviates from the depth of focus of laser light when a flexible transparent insulating substrate is used, a flexible transparent insulating substrate is fixed from both sides with a glass plate for correction. A method has been proposed in which the layer to be processed is sandwiched and held to ensure the flatness of the layer to be processed (see, for example, Japanese Patent Application Laid-Open
218471). However, in this method,
Since the layer to be processed on the transparent insulating substrate is in contact with the glass plate for correction and is in a sealed state, the evaporated substance has no escape area, recrystallizes and adheres in the scribe groove, and the area to be divided Cause a short circuit between them. Further, in this method, as shown in FIG.
The laser L irradiated for pattern processing of 1) passes through the correction glass plate 52, is irregularly reflected on the stage S on which the correction glass plate 52 is mounted, and reenters the periphery of the scribe groove SL1. As a result, the shape of the scribe groove SL1 becomes defective, and there is a problem that the scribe processing accuracy is remarkably reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser processing apparatus and method capable of forming a pattern such as a scribe groove with high accuracy and preventing a short circuit due to recrystallization of a thin film material once evaporated.

[0010]

According to a first aspect of the present invention, there is provided a laser processing apparatus which irradiates a layer to be processed laminated on one surface of a flexible transparent insulating substrate with a laser beam. A laser processing apparatus for forming a pattern on the layer to be processed, comprising: a stage made of a transparent material having a convexly curved surface; and a laser head portion disposed on the back side of the stage. And irradiating the processing target layer with laser light from the laser head section through the stage and the transparent insulating substrate in a state where the convex surface of the stage is in contact with the other surface of the transparent insulating substrate. And

In the laser processing apparatus according to the first aspect, the convex surface of the stage is in contact with the other surface of the transparent insulating substrate (the surface opposite to the surface on which the layer to be processed is laminated). Due to its flexibility, the insulating substrate comes into close contact with the surface of the stage, and the distance from the surface of the stage to the layer to be processed becomes substantially constant (corresponding to the thickness of the transparent insulating substrate). Therefore, by adjusting the laser light focusing system based on the position of the surface of the stage and the thickness of the transparent insulating substrate, the layer to be processed easily fits in the focal depth of the laser light and does not deviate therefrom. Further, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the laser beam transmitted through the layer to be processed is not reflected and re-enters the layer to be processed (near the pattern edge). Therefore, patterns such as scribe grooves are formed with high accuracy. In addition, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the evaporated thin film material does not recrystallize and adhere to the scribe grooves. Therefore, there is no risk of a short circuit between the regions to be divided.

According to a second aspect of the present invention, in the laser processing apparatus according to the first aspect, the stage is a member extending in one direction, and a cross section perpendicular to the one direction has a constant shape. And the curved outer edge of the cross section forms the convex surface.

According to the laser processing apparatus of the second aspect,
The strip-shaped transparent insulating substrate having a predetermined width in the one direction can be easily brought into contact along the convex surface by partially winding the convex surface of the stage. . In this state, one scribe groove extending in the one direction is formed by irradiating the transparent insulating substrate with laser light in the one direction. Further, after sliding the transparent insulating substrate by a predetermined amount in the winding direction, another scribe groove is formed in parallel with the scribe groove by irradiating the transparent insulating substrate with laser light along the one direction. Is formed. In this manner, scribe grooves can be formed one after another while sliding the transparent insulating substrate by a predetermined amount in the winding direction.

According to a third aspect of the present invention, there is provided the laser processing apparatus according to the second aspect, further comprising a transport unit configured to slide the transparent insulating substrate with a tension in a winding direction with respect to the stage. It is characterized by having.

In the laser processing apparatus of the third aspect, the transparent insulating substrate is slid in the winding direction with respect to the stage by the transfer means. Moreover, since the transparent insulating substrate is slid with tension in the winding direction,
The other surface of the transparent insulating substrate strongly contacts the surface of the stage. Therefore, the layer to be processed is more reliably set within the depth of focus of the laser beam, and the scribe groove is formed with higher accuracy. In addition to the parallel scribe grooves, various patterns can be formed by combining the movement of the transparent insulating substrate in the winding direction by the transport means and the movement of the laser head section in the one direction.

According to a fourth aspect of the present invention, in the laser processing apparatus according to the first, second, or third aspect, the stage is provided on a back surface side with the laser light incident from the laser head portion on the layer to be processed. A light condensing part for condensing light at a position where the pattern is to be formed.

In the laser processing apparatus of the present invention, the laser beam incident from the laser head is focused on a portion of the layer to be processed where a pattern is to be formed by the focusing part on the back side of the stage. . Therefore, there is no need to provide an objective lens for focusing on the laser head,
The device can be simplified. In addition, as a result of the reduction in the weight of the laser head portion, the one-way movement of the laser head portion is accelerated, and the speed of pattern processing is increased.

According to a fifth aspect of the present invention, in the laser processing apparatus according to the first, second or third aspect, a light blocking member is provided in a region of the stage in contact with the transparent insulating substrate. A slit having a width corresponding to the width of the pattern to be formed is formed in the blocking member.

In the laser processing apparatus according to the fifth aspect, the laser light is collimated by the objective lens of the laser head, and the collimated light is incident on the back side of the stage.
As a result, the pattern to be formed (such as a scribe groove) passes through the slit of the light blocking member provided on the stage.
The parallel light having a width corresponding to the width of the light is transmitted. The parallel light further passes through the transparent insulating substrate, and is irradiated on the layer to be processed to form a pattern. At this time, the width of the laser beam applied to the transparent insulating substrate is kept constant irrespective of the depth of focus of the objective lens, so that patterns such as scribe grooves are accurately formed. Moreover, good processing is performed irrespective of variations in the thickness of the transparent insulating substrate.

According to a sixth aspect of the present invention, in the laser processing apparatus according to the first, second or third aspect, the stage has an optical waveguide for guiding a laser beam from the back side to the front side of the stage. The optical waveguide has a width corresponding to the width of a pattern to be formed.

In the laser processing apparatus according to the sixth aspect, the laser light condensed by the objective lens of the laser head is incident on the optical waveguide provided on this stage.
Then, a laser beam having a width corresponding to the width of a pattern (a scribe groove or the like) to be formed is transmitted through the optical waveguide from the back side to the front side of the stage. This laser light further passes through the transparent insulating substrate, and is irradiated on the layer to be processed to form a pattern. The width of the laser light is determined by the width of the optical waveguide and the numerical aperture, and is kept constant irrespective of the depth of focus of the objective lens, so that a pattern such as a scribe groove is formed with high precision. Moreover, good processing is performed irrespective of variations in the thickness of the transparent insulating substrate.

According to a seventh aspect of the present invention, there is provided a laser processing method for irradiating a processing layer laminated on one surface of a flexible transparent insulating substrate with a laser beam to form a pattern on the processing layer. The laser processing method of the above, using a stage made of a transparent material having a convexly curved surface, in a state where the convex surface of the stage is in contact with the other surface of the transparent insulating substrate, the stage And irradiating the layer to be processed with laser light from the back side through the stage and the transparent insulating substrate.

According to the laser processing method of the present invention, the convex surface of the stage is in contact with the other surface of the transparent insulating substrate (the surface opposite to the surface on which the layer to be processed is laminated). However, due to its flexibility, the substrate comes into close contact along the surface of the stage, and the distance from the surface of the stage to the layer to be processed becomes substantially constant (the thickness of the transparent insulating substrate). Therefore, by adjusting the laser light focusing system based on the position of the surface of the stage and the thickness of the transparent insulating substrate, the layer to be processed easily fits in the focal depth of the laser light and does not deviate therefrom. Further, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the laser beam transmitted through the layer to be processed is not reflected and re-enters the layer to be processed (near the pattern edge). Therefore, a pattern is formed with high accuracy. Moreover, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the thin film material that has evaporated once does not recrystallize and adhere to the scribe grooves. Therefore, there is no risk of a short circuit between the regions to be divided.

[0024]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows a schematic configuration of a laser processing apparatus 1 according to one embodiment of the present invention.

The laser processing apparatus 1 includes an Nd: YAG laser oscillator LZ, an attenuator AT for adjusting the intensity of laser light, a slit FS for narrowing the laser light, and a condensing part for converging the laser light transmitted through the slit FS. Lens L
1, an optical fiber F for guiding the laser light focused by the condenser lens L1 to a working position, a laser head LH for scanning the processing target with the laser light received from the optical fiber F, It has a stage 2 to which the object contacts. BT indicates a power supply.

In this example, an object to be processed is a transparent electrode layer (not shown) or an amorphous photoelectric conversion layer (not shown in FIG. , An amorphous photoelectric conversion layer 12). The material of the transparent insulating substrate 9 is N
d: oscillation wavelength of YAG laser 1.06 μm and 534 n
A polymer compound such as polyimide, polycarbonate resin, or fluororesin, which is transparent in m, is used. The width of the transparent insulating substrate 9 is, for example, about 500 mm, and its thickness is 25 to
It is about 100 μm. The transparent electrode layer is made of SnO ₂ or ZnO
And the thickness thereof is about 1 μm. The amorphous photoelectric conversion layer is formed by stacking N-type, I-type, and P-type amorphous silicon layers, and has a thickness of about 0.4 μm.

The Nd: YAG laser oscillator LZ has Nd:
1.06 μm wavelength or 534 nm wavelength using YAG
(Second harmonic) laser light can be output. As will be described later, when processing the transparent electrode layer, the wavelength 1.
A laser beam having a wavelength of 534 nm (second harmonic) is output when processing an amorphous photoelectric conversion layer while outputting a laser beam of 06 μm.

The optical fiber F is a silica-based optical fiber having a very small propagation loss of several dB / km with respect to the YAG laser light. As its internal structure, a step index type with good beam confinement in the core is adopted in order to obtain durability against high peak output of pulse oscillation.

In this example, the laser head LH is provided with a variable slit VS for narrowing the laser beam received from the optical fiber F.
And an objective lens L2 for focusing the laser light transmitted through the slit VS. The focal length of the objective lens L2 is 50 mm, and its optical axis is directed in the vertical direction. The laser light L emitted from the laser head LH is focused vertically below the objective lens L2. The laser head LH is supported by a drive mechanism (not shown) and is moved in one direction (y direction) in a horizontal plane as described later.

The stage 2 is made of dielectric transparent glass, and has a semi-cylindrical shape obtained by dividing a cylinder into two parts by a plane passing through a central axis. The outer diameter of stage 2 is 200 mm,
The inside diameter is set to 190 mm (thus, the thickness is 5 mm), and the length in the longitudinal direction is set to 800 mm. As the transparent glass, various glass such as quartz glass, soda-lime glass, borosilicate glass, and lead glass can be used. Since this stage 2 has a relatively simple shape,
It can be easily manufactured. The stage 2 is disposed directly below the laser head LH with the convexly curved front surface 2a facing downward, the concavely curved back surface 2b facing upward, and the longitudinal direction oriented in the y direction. The stage 2 is fixedly supported by a support member (not shown).

On both sides of the stage 2 in the x direction (the direction perpendicular to the y direction in the horizontal plane), cylindrical transfer drums D1 and D2 are arranged, respectively. Each transport drum D1, D
Numeral 2 is rotatably supported by support members (not shown) around respective central axes with its longitudinal direction oriented in the y direction, and is rotated by rotating means (not shown).

A transparent insulating substrate 9 (having a transparent electrode layer and an amorphous photoelectric conversion layer laminated on one surface 9a) is wound on the drum D1 in advance. When laser processing is performed, the drum D1 is rotated clockwise in FIG.
1, the transparent insulating substrate 9 is sent out, and the transparent insulating substrate 9 is wound around the lowermost part of the surface 2a of the stage 2 and between the meandering correction rolls CR1 and CR2 and between the meandering correction rolls CR3 and CR.
A state is taken in which the drum D2 is wound clockwise in FIG.
By controlling the rotation of the transport drums D1 and D2, a certain tension is applied to the transparent insulating substrate 9 so that the other surface 9b of the transparent insulating substrate 9 is pressed against the surface 2a of the stage 2. Thereby, the surface 9 b of the transparent insulating substrate 9 can be slid close to the surface 2 a of the stage 2. Specifically, the tension applied to the transparent insulating substrate 9 is 1 to 3
Set within the range of 0 kg / cm ² .

The meandering correction rolls CR1, CR2 and CR
3 and CR4 are controlled by control means (not shown) based on the outputs of the meandering detection sensors SC1 and SC2.
Thereby, the transparent insulating substrate 9 can be brought into contact with the predetermined position of the stage 2 in the y direction, and the transfer drum D
The winding state of D1 and D2 can be kept good.

This laser processing apparatus is used as follows when performing pattern processing of a transparent electrode layer and an amorphous photoelectric conversion layer of an integrated solar cell similar to that shown in FIG.

First, only a transparent electrode layer is laminated as a layer to be processed on the surface 9 a of the transparent insulating substrate 9, and a scribe groove is formed in this transparent electrode layer.

In this case, the Nd: YAG laser oscillator LZ
Output a laser beam having a wavelength of 1.06 μm. This laser light is supplied to an attenuator AT, a slit FS, and a condenser lens L.
The laser beam is guided to the laser head LH through the optical fiber 1 and the optical fiber F, and is incident on the back surface 2b side of the stage 2 through the variable slit VS of the laser head LH and the objective lens L2.
Then, an image is formed through the stage 2 and the transparent insulating substrate 9 at the position of the transparent electrode layer which is the layer to be processed. The laser beam intensity and the image size are set in advance to appropriate values for forming the scribe grooves. Assuming that the refractive index of the transparent glass material of the stage 2 is 1.5 and the refractive index of the transparent insulating substrate 9 (for example, made of fluororesin) is 1.6, the air and the stage 2 are calculated by the Fresnel calculation formula. At the interface with
% Reflection, 3 at the interface between the stage 2 and the transparent insulating substrate 9
There is only% reflection. Therefore, most of the condensed laser light L reaches the transparent electrode layer which is the layer to be processed.

At this time, the transparent insulating substrate 9 comes into close contact with the surface 2a of the stage 2 due to its flexibility, and the distance from the surface 2a of the stage 2 to the layer to be processed is substantially constant (the thickness corresponding to the thickness of the transparent insulating substrate 9) ), The laser light focusing system is adjusted based on the position of the surface 2 a of the stage 2 and the thickness of the transparent insulating substrate 9, so that the layer to be processed easily fits in the focal depth of the laser light. , It will not come off.

In this state, by moving the laser head LH in the y direction and scanning the transparent insulating substrate 9 with the laser light L, one scribe groove extending in the y direction can be formed. Next, the transporting drums D1 and D2 are rotated to slide the transparent insulating substrate 9 by a certain amount in the x direction, that is, substantially in the winding direction. Then, the laser head LH
Is moved in the y direction to scan the transparent insulating substrate 9 with the laser beam L. Thereby, another scribe groove can be formed in parallel with the scribe groove. In this way, scribe grooves can be formed one after another while sliding the transparent insulating substrate 9 in the winding direction by a fixed amount. The transfer drums D1 and D2 may be rotated continuously from the rotational position where one scribe groove is formed to the rotational position where the next scribe groove is formed, or may be rotated stepwise.

In this manner, the scribe groove can be formed with high accuracy while the layer to be processed is always kept at the focal depth of the laser beam. Also, since the surface 9a of the transparent insulating substrate 9 on which the layer to be processed is laminated is open, the laser beam transmitted through the layer to be processed is reflected and re-enters the layer to be processed (near the scribe groove). Absent. Therefore, the scribe grooves are formed with high precision. Moreover, the transparent insulating substrate 9
Since the surface 9a side on which the layer to be processed is laminated is open, the thin film material once evaporated does not recrystallize and adhere to the scribe grooves. Therefore, a short circuit between the regions to be divided can be prevented.

Next, on the surface 9 a of the transparent insulating substrate 9, a transparent electrode layer in which a scribe groove is already formed and an amorphous photoelectric conversion layer are laminated, and the scribe groove is formed on the amorphous photoelectric conversion layer. Is formed.

In this case, the Nd: YAG laser oscillator LZ
Output a laser beam (second harmonic) having a wavelength of 534 nm. As described above, this laser beam is
T, slit FS, condenser lens L1 and optical fiber F
To the laser head LH through the laser head L
The light is made to enter the back surface 2b side of the stage 2 through the H variable slit VS and the objective lens L2. And stage 2,
An image is formed at the position of the amorphous photoelectric conversion layer, which is the layer to be processed, through the transparent insulating substrate 9 and the transparent electrode layer. At this time, since the wavelength of the laser beam is as short as 534 nm, the laser beam is not absorbed by the transparent electrode layer, but is absorbed by the amorphous photoelectric conversion layer to evaporate the material of this layer.

Also in this case, the scribe grooves can be formed with high accuracy, as in the above case. Moreover, the thin film material once evaporated does not recrystallize and adhere to the scribe grooves.
A short circuit between regions to be divided can be prevented.

FIG. 2 shows a modification 2A of the stage 2. The stage 2A has, on a concavely curved back surface 2c of the stage 2, a semi-cylindrical light collector 2c made of the same transparent glass material as the semi-cylindrical portion of the stage and extending in the y direction. The condensing portion 2c condenses the laser light L incident from the laser head portion LH on a portion where a pattern of the layer to be processed is to be formed. Therefore, the laser head LH
In addition, the objective lens L2 for condensing light can be omitted, and the apparatus can be simplified. Further, as a result of the lightening of the laser head portion LH, the scanning speed of the laser beam in the y direction can be increased,
The speed of forming patterns such as scribe grooves can be increased.

FIG. 3 shows another modification 2B of the stage 2. The stage 2B includes a light blocking member 21 in a region in contact with the transparent insulating substrate 9, that is, in the lowermost portion of the convex surface 2a. The light blocking member 21 is made of a metal such as silver or aluminum by a sputtering method or a vapor deposition method, and is embedded in the surface 2 a so as not to change the outer diameter of the stage 2. A slit 22 having a width corresponding to the width of the pattern to be formed and extending in the y direction is formed at the center of the light shielding member 21. When this stage 2B is used, the laser light L is converted into parallel light by the objective lens L2 of the laser head LH, and the parallel light is
B is incident on the back side. As a result, parallel light having a width corresponding to the width of a pattern (such as a scribe groove) to be formed is transmitted through the slit 22 of the light blocking member 21 provided on the stage 2B. This parallel light is further transmitted to the transparent insulating substrate 9.
, And the pattern is formed by irradiating the layer to be processed laminated on the surface 9a. In this case, the width of the formed pattern can be kept constant regardless of the depth of focus of the objective lens L2. Therefore, patterns such as scribe grooves can be formed with high precision. Moreover, good processing can be performed irrespective of variations in the thickness of the transparent insulating substrate 9.

FIG. 4 shows still another modification 2C of the stage 2.
Is shown. The stage 2C has an optical waveguide 32 for guiding the laser light L from the back surface 2b to the front surface 2a. The optical waveguide 32 has a higher refractive index than the guide portions 31 on both sides in the x direction, and extends in the y direction with a width corresponding to the width of a pattern to be formed. When this stage 2C is used, the objective lens L of the laser head LH is used.
The laser light L condensed by the stage 2
Is incident on the optical waveguide 32 provided in the optical waveguide. Then, laser light having a width corresponding to the width of a pattern (such as a scribe groove) to be formed is transmitted through the optical waveguide 32 from the back surface 2b side of the stage 2C to the front surface 2a side. This laser light further passes through the transparent insulating substrate 9 and is irradiated on the layer to be processed laminated on the surface 9a to form a pattern. In this case, the width of the formed pattern is determined by the width of the optical waveguide 32 and the numerical aperture, and can be kept constant regardless of the focal depth of the objective lens L2. Therefore, patterns such as scribe grooves can be formed with high precision. Moreover, good processing can be performed irrespective of variations in the thickness of the transparent insulating substrate 9.

The optical waveguide 32 is formed using a general ion exchange method, for example, as follows. That is, the soda glass is immersed in a potassium nitrate or potassium sulfate solution and heated to 300 to 400 ° C. This allows
The sodium ions in the soda glass and the potassium ions in the solution are exchanged, and the potassium ions diffuse into the glass. In this case, the refractive index becomes higher on the surface side where potassium is more diffused. Conversely, by placing glass containing potassium in a solution of sodium nitrate or sodium sulfate and heating, the refractive index can be made smaller on the surface side where more sodium is diffused. If silver or potassium is used as the ion to be exchanged, a large change in the refractive index of about 0.1 can be obtained. By using this method, the optical waveguide 3 having a large refractive index is provided inside a guide portion 31 made of a glass material having a small refractive index.
Form 2 As another method, a method of forming a film containing germanium on the surface, diffusing germanium into the glass by annealing at 300 to 400 ° C., and increasing the refractive index as the surface on which germanium is more diffused is increased. It can also be used.

In this embodiment, the case where the scribe grooves are formed parallel to the layer to be processed has been described. However, the present invention is not limited to this. In this laser processing apparatus, various patterns are formed by combining the movement of the transparent insulating substrate 9 in the x direction by the transfer drums D1 and D2 with the scanning of the laser light in the y direction by the movement of the laser head LH. can do.

When the scribe groove is formed, a strip-shaped laser beam which is elongated in the y direction may be emitted by the laser head. Thus, the means for moving the laser head in the y direction can be omitted.

The back electrode layer of the integrated solar cell (FIG. 6)
It corresponds to the back electrode layer 13 in the middle, and is usually made of a silver thin film having a thickness of about 0.2 μm. ) When performing pattern processing
The laser head LH is disposed directly below the stage 2, that is, on the side directly facing the layer to be processed.
, A laser beam having a wavelength of 534 nm is directly applied to the back electrode layer. Thereby, it is possible to avoid processing of the amorphous photoelectric conversion layer accompanying processing of the back electrode layer. Also,
The transparent insulating substrate 9 is closely contacted along the surface 2a of the stage 2 due to its flexibility, and the distance from the surface 2a of the stage 2 to the layer to be processed is substantially constant (the thickness of the transparent insulating substrate 9). By adjusting the laser light focusing system based on the position of the surface 2a of the stage 2 and the thickness of the transparent insulating substrate 9, the layer to be processed easily fits in the focal depth of the laser light and does not come off from it. Therefore, patterns such as scribe grooves can be formed with high accuracy. Moreover, since the surface 9a of the transparent insulating substrate 9 on which the layer to be processed is laminated is open, the thin film material that has evaporated once does not recrystallize and adhere to the scribe grooves. Therefore, a short circuit between the regions to be divided can be prevented.

[0051]

As is apparent from the above, in the laser processing apparatus of the first aspect, the convex surface of the stage is the other surface of the transparent insulating substrate (the surface opposite to the surface on which the layer to be processed is laminated).
, The layer to be processed easily fits in the depth of focus of the laser beam and does not come off from it. Also, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open,
The laser light transmitted through the processed layer is not reflected and re-enters the processed layer (near the pattern edge). Therefore, patterns such as scribe grooves can be formed with high accuracy. Moreover, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the evaporated thin film material does not recrystallize and adhere to the scribe grooves, and short-circuits between regions to be divided can be prevented. Can be prevented.

In the laser processing apparatus according to the second aspect, the stage is a member extending in one direction, the cross section perpendicular to the one direction has a constant shape, and the curved outer edge of the cross section is Since the convex surface is formed, a band-shaped transparent insulating substrate having a predetermined width in the one direction is obtained by partially winding the convex surface of the stage.
The contact can be easily made along the convex surface. In this state, scribe grooves can be formed one after another while sliding the transparent insulating substrate by a predetermined amount in the winding direction.

In the laser processing apparatus according to the third aspect of the present invention, the transparent insulating substrate is slid with respect to the stage with a tension in the winding direction by the transfer means.
The other surface of the transparent insulating substrate can be strongly brought into close contact with the surface of the stage. Therefore, the layer to be processed can be more reliably set within the focal depth of the laser beam, and the scribe groove can be formed more accurately. In addition to the parallel scribe grooves, various patterns can be formed by combining the movement of the transparent insulating substrate in the winding direction by the transport means and the movement of the laser head section in the one direction.

According to a fourth aspect of the present invention, the laser beam incident from the laser head is focused on a portion of the layer to be processed where a pattern is to be formed by the focusing portion on the back side of the stage. Therefore, there is no need to provide an objective lens for condensing light in the laser head, and the apparatus can be simplified. Further, as a result of the weight reduction of the laser head portion, the one-way movement of the laser head portion can be accelerated, and the pattern processing speed can be increased.

In the laser processing apparatus according to the fifth aspect, a light blocking member is provided in a region of the stage in contact with the transparent insulating substrate, and the light blocking member has a width corresponding to a width of a pattern to be formed. Since the slit having the slit is formed, the width of the laser light irradiated on the transparent insulating substrate is made constant regardless of the depth of focus of the objective lens by making parallel light incident on the back side of the stage from the laser head. Can be kept. Therefore, patterns such as scribe grooves can be formed with high accuracy. Moreover, good processing can be performed irrespective of variations in the thickness of the transparent insulating substrate.

In the laser processing apparatus according to the sixth aspect, the width of the laser light transmitted through the optical waveguide can be determined by the width of the optical waveguide and the numerical aperture, and is constant regardless of the focal depth of the objective lens. Can be kept. Therefore, patterns such as scribe grooves can be formed with high accuracy. Moreover, good processing can be performed irrespective of variations in the thickness of the transparent insulating substrate.

According to the laser processing method of the present invention, the convex surface of the stage is brought into contact with the other surface of the transparent insulating substrate (the surface opposite to the surface on which the layer to be processed is laminated). Therefore, the layer to be processed easily fits in the focal depth of the laser beam,
It will not come off. Further, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the laser beam transmitted through the layer to be processed is not reflected and re-enters the layer to be processed (near the pattern edge). Therefore, patterns such as scribe grooves can be formed with high accuracy. Moreover, since the surface of the transparent insulating substrate on which the layer to be processed is laminated is open, the evaporated thin film material does not recrystallize and adhere to the scribe grooves, and short-circuits between regions to be divided can be prevented. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a laser processing apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing a modification of a stage used in the laser processing apparatus.

FIG. 3 is a view showing another modification of the stage used in the laser processing apparatus.

FIG. 4 is a view showing another modification of the stage used in the laser processing apparatus.

FIG. 5 is a view for explaining a problem of a conventional laser processing apparatus.

FIG. 6 is a perspective view showing a structure of a general integrated type thin film solar cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2, 2A, 2B, 2C Stage 2c Condensing part 9 Transparent insulating substrate 32 Optical waveguide D1, D2 Transport drum LZ Laser oscillator F Optical fiber LH Laser head part

Claims (7)

[Claims] 1. A laser processing apparatus for irradiating a layer to be processed laminated on one surface of a transparent insulating substrate having flexibility with a laser beam to form a pattern on the layer to be processed. A stage made of a transparent material having a curved surface, and a laser head disposed on the back side of the stage, wherein the convex surface of the stage is in contact with the other surface of the transparent insulating substrate. In the state, a laser beam is radiated from the laser head section to the layer to be processed through the stage and the transparent insulating substrate. 2. The laser processing apparatus according to claim 1, wherein the stage is a member extending in one direction, a cross section perpendicular to the one direction has a constant shape, and a curved outer edge of the cross section. A laser processing apparatus, wherein a portion forms the convex surface. 3. The laser processing apparatus according to claim 2, further comprising a transport unit configured to slide the transparent insulating substrate with a tension in a winding direction with respect to the stage. . 4. The laser processing apparatus according to claim 1, wherein the stage collects laser light incident from the laser head portion on a back surface side at a position where a pattern of the processing target layer is to be formed. A laser processing apparatus, comprising: a light condensing part for emitting light. 5. The laser processing apparatus according to claim 1, wherein a light blocking member is provided in a region of the stage in contact with the transparent insulating substrate, and the light blocking member has a pattern to be formed. A laser processing apparatus, wherein a slit having a width corresponding to the width is formed. 6. The laser processing apparatus according to claim 1, wherein the stage has an optical waveguide for guiding a laser beam from the back side to the front side of the stage, and the optical waveguide should be formed. A laser processing apparatus having a width corresponding to the width of a pattern. 7. A laser processing method for irradiating a layer to be processed laminated on one surface of a transparent insulating substrate having flexibility with a laser beam to form a pattern on the layer to be processed. A stage made of a transparent material having a curved surface is used, and the stage and the transparent insulating layer are arranged from the back side of the stage in a state where the convex surface of the stage is in contact with the other surface of the transparent insulating substrate. A laser processing method comprising irradiating the layer to be processed with laser light through a substrate.