JP2005014083A - Laser beam machining device and laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To subject a thin film deposited on a substrate to laser beam machining in a clean environment. <P>SOLUTION: A flexible substrate 2 is attracted on a sucking stage 5, and the laser beam machining face 2a thereof is made vertical. A galvanomirror 7 is arranged on a normal at the center of the laser beam machining face 2a, and by the combination of the angles of two reflectors 7a and 7b, a laser beam oscillated from a laser oscillator 9 is applied to the desired position on the laser beam machining face 2a. Since the laser beam machining face 2a is vertical and the galvanomirror 7 is not arranged in the vertical lower region thereof, the scattering of machining dust produced on the removal of a thin film over the laser beam machining face 2a and the galvanomirror 7 can remarkably be reduced, thereby a clean laser beam machining process can be realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a laser processing apparatus and a laser processing method for processing a thin film formed on a substrate using a laser in the manufacture of a thin film solar cell.
[0002]
[Prior art]
Non-single-crystal silicon-based thin films such as amorphous silicon (a-Si), amorphous silicon germanium (a-SiGe), and microcrystalline silicon formed by glow discharge decomposition of source gas and photo CVD (Chemical Vapor Deposition) Since it can be formed by a growth method, it has a feature that it is easy to increase the area. Furthermore, these non-single-crystal silicon thin films have a feature that they can be formed on a substrate such as a plastic film because the formation temperature is low.
[0003]
When a thin-film solar cell is formed using such a non-single-crystal silicon thin film, an integrated series connection structure can be realized using an insulating material such as glass or plastic film on the substrate, and several tens of volts or more can be obtained from a single substrate. There is an advantage that a high voltage of several hundred volts can be taken out. As a serial connection structure, for example, as disclosed in JP-A-6-342924, a structure in which strip-shaped elements are connected on one surface using a light-transmitting insulating substrate such as glass, or a plastic film substrate There is a structure in which a device is formed in a strip shape on the main surface, a connection electrode is formed on the back surface, and the device is connected through a connection hole.
[0004]
In order to realize such a series connection structure, a technique for separating and processing a non-single crystal silicon thin film uniformly formed on a large area substrate having a side of about 0.3 m to 2 m in a strip shape is necessary. In such separation processing, the following conditions (1) to (3) are mainly required.
[0005]
(1) A clean machining process that does not generate pinholes.
(2) The processing line width is about 10 μm to 500 μm and the stability is good.
(3) The processing position accuracy is good.
[0006]
A laser processing technique that satisfies these conditions and is most commonly used at present is a YAG (Yttrium Aluminum Garnet) laser beam. As a laser processing apparatus used for thin film separation processing, a substrate is adsorbed on an XY stage, and the XY stage is moved in the X direction or Y direction to scan the substrate with laser light. There is. FIG. 4 is a diagram for explaining an example of a conventional laser processing apparatus. As shown in FIG. 4, the substrate 100 is fixed to the XY stage 101, the laser light is guided to the emission optical unit 103 by the fiber optical system 102, and the substrate is moved while the emission optical unit 103 is moved in the X direction or the Y direction. Some scan 100 with laser light 104.
[0007]
Further, there has also been proposed a device in which a galvano mirror can be used to two-dimensionally irradiate a laser beam at a desired position on a laser processing surface. By using a laser processing apparatus using a galvanometer mirror for thin film separation processing, a large area substrate of 1 m square or more can be processed at high speed, and the cost of the thin film solar cell can be reduced.
[0008]
Conventionally, as a laser processing apparatus using a galvanometer mirror, for example, while an active material applied to a battery electrode plate such as a lithium secondary battery is being transferred by a roller of an electrode material on which the electrode plate is formed, An apparatus has been proposed in which a galvano mirror is used to irradiate laser light from above and scan at a speed of 0.6 m / s to sublimate and remove the active material in the irradiated portion. Furthermore, in this proposal, compressed air is blown from the nozzle plate surface and the nozzle having an inclination angle to the laser beam in the vicinity of the irradiation spot of the laser beam, and a smoke-like object of the active material generated at the time of sublimation of the active material is blown off. An apparatus is shown that collects it with a dust collection duct (see Patent Document 1).
[0009]
[Patent Document 1]
JP 2000-149911 A (paragraph numbers [0018] to [0020], [0025], FIGS. 1 and 2)
[0010]
[Problems to be solved by the invention]
In thin film separation processing in the manufacture of thin film solar cells, gas containing processing dust is generated from the thin film when the thin film is sublimated and removed by irradiation with laser light, so the galvanometer mirror can achieve high speed and low cost. In order to perform thin film separation processing by a laser processing apparatus using a laser in a clean environment, several problems that may be caused by such processing dust must be solved. Specifically, there are the following problems.
[0011]
First, in the case of a laser processing apparatus of a type that does not blow compressed air at the time of laser processing, first, if processing is performed with the laser processing surface facing upward, processing dust accumulates on the laser processing surface, and in particular, trying to process from now on. It is difficult to remove the processing dust adhering to the portion to be removed by a dry process. Secondly, when a laser optical system including a galvanometer mirror is disposed below with the laser processing surface of the substrate facing downward, a protective glass is required to prevent processing dust from falling on and adhere to the optical system. . However, in laser processing using a galvanometer mirror, the laser light is irradiated with an angle, so that the laser light is refracted when passing through the protective glass, which causes a reduction in processing accuracy. Third, regardless of whether the laser processing surface is facing upward or downward, if the processing dust contained in the gas generated when the thin film is irradiated with laser blocks the optical path of the laser beam, the thin film processing state is affected. It will end up.
[0012]
In addition, in the manufacture of thin film solar cells, the substrate has become larger in area, and one side of the substrate is often 1 m or more. Therefore, in the conventional laser processing apparatus that blows compressed air near the irradiation spot during laser processing, the effect of gas containing processing dust generated in laser processing of a thin film formed on such a large area substrate is effective. It is difficult to eliminate.
[0013]
The present invention has been made in view of these points, and provides a laser processing apparatus and a laser processing method for realizing high productivity at a low cost and realizing a laser processing process in a clean environment. The purpose is to provide.
[0014]
[Means for Solving the Problems]
In the present invention, in order to solve the above problem, in a laser processing apparatus for irradiating a substrate on which a thin film is formed with laser light to remove a part of the thin film, a laser processing surface of the substrate on which the laser light is irradiated Is arranged vertically or vertically downward, and a galvanometer mirror for adjusting the irradiation position of the laser beam on the laser machined surface and scanning the laser beam on the laser machined surface is outside the vertically lower region of the laser machined surface. A laser processing apparatus is provided, wherein the laser processing apparatus is disposed on a normal line in the center of the laser processing surface.
[0015]
According to such a laser processing apparatus, the galvanometer mirror that adjusts the irradiation position of the laser beam on the laser processing surface is located outside the vertical lower region of the laser processing surface of the substrate arranged vertically or vertically downward, at the center of the laser processing surface. Since it is arranged on the normal line, scattering and adhesion of the processing dust generated when removing the thin film to the laser processing surface and the galvanometer mirror are reduced.
[0016]
In the present invention, in the laser processing method for removing a part of the thin film by irradiating a laser beam onto the substrate on which the thin film is formed, the laser processing surface of the substrate is arranged vertically or vertically downward, and the vertical or vertical The laser processing surface is irradiated with the laser light by using a galvano mirror disposed outside the vertically lower region of the laser processing surface disposed downward and on the normal line of the center of the laser processing surface. A laser processing method is provided.
[0017]
According to such a laser processing method, a laser is applied to the laser processing surface by using a galvanometer mirror disposed on the normal line of the center of the laser processing surface outside the vertically lower region of the laser processing surface of the substrate disposed vertically or vertically downward. Since light is irradiated, scattering and adhesion of the processing dust generated when removing the thin film to the laser processing surface and the galvanometer mirror are reduced.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, a first embodiment will be described.
[0019]
FIG. 1 is a schematic view of the laser processing apparatus according to the first embodiment.
The laser processing apparatus 1 includes an unwinding roll 3 in which a flexible substrate 2 in which a thin film is formed on a flexible polyimide film material having a thickness of 50 μm is wound around a roll core having a diameter of 150 mm, the unwinding roll 3 has a take-up roll 4 on which the flexible substrate 2 fed from 3 is taken up. Between the unwinding roll 3 and the take-up roll 4, an adsorption surface 5a for adsorbing the flexible substrate 2 is provided on the back surface side of the laser processing surface 2a that is a range processed by the laser beam of the flexible substrate 2. A suction stage 5 is disposed. Here, the suction stage 5 is arranged so that the suction surface 5a is vertical. A marker detector 6 for detecting a marker hole 2b formed in a predetermined position on the flexible substrate 2 is disposed on the laser processing surface 2a side of the flexible substrate 2.
[0020]
Further, in the laser processing apparatus 1, a galvanometer mirror 7 is disposed on the laser processing surface 2a side of the flexible substrate 2 and on the normal line of the laser processing surface 2a center on the suction surface 5a. Since the galvanometer mirror 7 is not restricted in its mounting posture, it can be processed with the laser processing surface 2a of the flexible substrate 2 vertical. Such a galvanometer mirror 7 has a configuration in which two reflection mirrors 7a and 7b can be rotated by rotation drive mechanisms 7c and 7d such as servo motors, respectively. On the incident side to the galvanometer mirror 7, a focus adjustment lens 8 for adjusting the laser beam to be focused on the laser processing surface 2 a is disposed, and a laser oscillator 9 is disposed via the focus adjustment lens 8. ing. The galvano mirror 7, the focus adjustment lens 8, and the laser oscillator 9 are driven and controlled by the control unit 10.
[0021]
In this laser processing apparatus 1, the galvano mirror 7 adjusts the irradiation position of the laser light oscillated from the laser oscillator 9 on the laser processing surface 2a to a desired position at a high speed by combining the angles of the reflection mirrors 7a and 7b. It can be moved. For example, the two reflection mirrors 7a and 7b are driven by the rotation drive mechanisms 7c and 7d that can move the irradiation position of the laser beam at a speed of about 0.9 m / s. Thereby, if the laser processing surface 2a is, for example, 1 m square, the irradiation position of the laser light can be moved from one end to the other end of the laser processing surface 2a in about 1 second. In the case of movement during non-processing in which the laser beam is moved from an irradiation end position to the next irradiation start position, the reflection mirrors 7a and 7b may be driven at a higher speed.
[0022]
Further, the laser processing apparatus 1 is configured to directly irradiate the laser processing surface 2a with laser light with an angle without using a condensing Fθ lens by using a galvano mirror 7.
[0023]
In laser processing of the flexible substrate 2 by the laser processing apparatus 1 having such a configuration, first, the marker hole 2b serves as a positioning reference for the flexible substrate 2 fed from the unwinding roll 3, and the marker hole 2b. Is detected by the marker detector 6, and the feeding is stopped. The flexible substrate 2 whose feeding has been stopped is adsorbed on the adsorption surface 5 a of the back surface of the laser processed surface 2 a and temporarily fixed on the adsorption stage 5.
[0024]
The laser processing surface 2a of the flexible substrate 2 fixed to the suction stage 5 is subjected to laser processing in a predetermined pattern, for example, a strip shape. At that time, the laser light is oscillated from the laser oscillator 9 based on a command from the control unit 10, is incident on the focus adjustment lens 8, and is irradiated to the irradiation position according to the angles of the reflection mirrors 7 a and 7 b. The thin film formed at the laser beam irradiation position on the laser processing surface 2a is heated and sublimated by the laser beam irradiation.
[0025]
In the laser processing apparatus 1 according to the first embodiment, the suction stage 5 with the suction surface 5a being vertical is used, and the laser processing surface 2a is vertical. Therefore, machining dust contained in the gas generated from the thin film during sublimation. Scattering and deposition on the laser processing surface 2a are greatly reduced. Moreover, in this laser processing apparatus 1, since the galvanometer mirror 7 is not disposed in the vertically lower region of the laser processing surface 2a, the processing dust does not fall on the galvanometer mirror 7, and the scattering of the processing dust to the galvanometer mirror 7 occurs. Adhesion is greatly reduced. Furthermore, no protective glass is required, and processing accuracy can be improved.
[0026]
FIG. 2 is a diagram showing another arrangement relationship between the laser processed surface and the galvanometer mirror. However, in FIG. 2, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0027]
In FIG. 2, the suction stage 5 is arranged with its suction surface 5a facing vertically downward, whereby the laser processing surface 2a of the flexible substrate 2 is arranged vertically downward. This is different from the example shown in FIG. 1 in which the suction surface 5a is arranged vertically. As shown in FIG. 2, even if the suction surface 5a is directed vertically downward at an angle, the galvano mirror 7 is outside the vertical lower region 20 of the laser processing surface 2a on the suction surface 5a and is in the center of the laser processing surface 2a. If it is arrange | positioned on this normal line, scattering to the laser processing surface 2a and the galvanometer mirror 7 of the processing dust which generate | occur | produces when a laser beam is irradiated to the laser processing surface 2a can be suppressed.
[0028]
As described above, in the laser processing apparatus 1 of the first embodiment, the laser processing surface 2a of the flexible substrate 2 is arranged so as to be vertical or vertically downward, and the galvanometer mirror 7 is disposed on the laser processing surface 2a. It arrange | positions on the normal line of the laser processing surface 2a center outside a vertically downward area | region, and a laser beam is irradiated to the laser processing surface 2a. Thereby, scattering of the processing dust to the laser processing surface 2a and the galvanometer mirror 7 is suppressed, and a laser processing process in a clean environment can be realized.
[0029]
Next, a second embodiment will be described.
FIG. 3 is a schematic cross-sectional view of an essential part of the laser processing apparatus according to the second embodiment. However, in FIG. 3, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0030]
In the laser processing apparatus 30 shown in FIG. 3, a spray nozzle 31 having a length equal to or longer than the length in the width direction of the laser processing surface 2a is disposed at one end of the suction stage 5 on the suction surface 5a side. The spray nozzle 31 is connected to a compressor 32 so that compressed air is blown from the spray nozzle 31. Further, the other end on the suction surface 5a side of the suction stage 5 and facing the spray nozzle 31 has a length equal to or greater than the length in the width direction of the laser processing surface 2a, like the spray nozzle 31. A suction duct 33 for sucking compressed air blown out from the nozzle 31 and gas containing processing dust is disposed. The suction duct 33 is connected to the exhaust pump 34. The blowing nozzle 31 and the compressor 32 constitute air blowing means of the laser processing apparatus 30, and the suction duct 33 and the exhaust pump 34 constitute suction means of the laser processing apparatus 30.
[0031]
In the relationship with the laser beam scanning direction, the air blowing unit and the suction unit are arranged such that the blowing nozzle 31 is disposed on the end point side when scanning the laser beam, and the suction duct 33 is disposed on the starting point side when scanning the laser beam. It is configured to be. That is, the compressed air flowing from the spray nozzle 31 toward the suction duct 33 flows so as to face the laser beam scanning direction.
[0032]
Although not shown in FIG. 3, the laser processing apparatus 30 has a pair of spray nozzles and a suction duct arranged in a direction orthogonal to the flow direction of the compressed air flowing from the spray nozzle 31 to the suction duct 33. The air blow means and the suction means are configured by being connected to the compressor and the exhaust pump, respectively. Also in this case, the compressed air flows so as to face the laser beam scanning direction.
[0033]
Here, the laser processing apparatus 30 of the second embodiment has a configuration in which such an air blow unit and a suction unit are provided in the laser processing apparatus 1 of the first embodiment.
[0034]
Using such a laser processing device 30, for example, the flow velocity of the compressed air flowing from the spray nozzle 31 to the suction duct 33 on the adsorption stage 5 is set to about 4 m / s, and the galvano mirror 7 changes the laser light in the flow direction of the compressed air. Laser processing is performed by scanning in the opposite direction at a speed of 0.9 m / s. When the laser processing surface 2a of the flexible substrate 2 adsorbed on the adsorption surface 5a is irradiated with laser light under such conditions, the thin film at the irradiation position is heated by the laser light irradiation and sublimates. At that time, the gas containing the processing dust generated at the time of sublimation is blown off by the compressed air blown from the blowing nozzle 31 and sucked into the suction duct 33 together with the compressed air. Similarly, when the laser beam is scanned in a direction orthogonal to the laser scanning direction shown in FIG. 3, the gas containing the processing dust is sucked into the suction duct together with the compressed air from the spray nozzle.
[0035]
As described above, in the laser processing apparatus 30 having the air blowing means and the suction means, the gas containing the processing dust generated at the time of laser processing is blown off and sucked by the compressed air blown facing the laser beam scanning direction. . By flowing compressed air in a direction opposite to the laser beam scanning direction and preventing the machining dust from flowing in the machining progress direction, adhesion of the machining dust to the portion to be machined is greatly reduced. In this laser processing apparatus 30, the laser processing surface 2a may face either vertically or vertically downward, and in either case, as shown in FIG. 1 or FIG. 7 is arranged outside the vertically lower region of the laser processing surface 2a and on the normal line of the center of the laser processing surface 2a. Thereby, scattering of the machining dust to the laser machined surface 2a and the galvanometer mirror 7 is greatly reduced, and a cleaner and more reliable laser machining process can be realized.
[0036]
However, in this laser processing apparatus 30, since the arrangement relationship between the spray nozzle 31 and the suction duct 33 is fixed, the laser beam scanning direction is limited to the direction facing the flow direction of the compressed air. Therefore, the movement distance at the time of non-processing which moves the irradiation position of the laser beam on the laser processing surface 2a from a certain irradiation end position to the next irradiation start position becomes long. In this regard, the laser processing apparatus 30 moves the galvanometer mirror 7 at a high speed so that it does not become a factor that hinders productivity even if the moving distance during non-processing increases.
[0037]
In the second embodiment, the case where the air blowing means and the suction means are provided in the laser processing apparatus 1 of the first embodiment has been described as an example. The present invention can also be applied to other laser processing apparatuses, for example, a conventional laser processing apparatus in which a laser processing surface is horizontally arranged.
[0038]
【The invention's effect】
As described above, in the present invention, the laser processing surface of the substrate is disposed vertically or vertically downward, and the laser is used by using the galvanomirror disposed on the normal line at the center of the laser processing surface outside the vertically lower region of the laser processing surface. Laser light is irradiated to the processed surface. This greatly reduces the scattering of processing dust generated during thin film removal to the laser processing surface and galvanometer mirror, and realizes a clean laser processing process using a laser processing device using a low-cost, high-productivity galvanometer mirror. it can.
[0039]
Furthermore, by providing an air blow means and a suction means in such a laser processing apparatus, a cleaner and more reliable laser processing process can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic view of a laser processing apparatus according to a first embodiment.
FIG. 2 is a diagram showing another arrangement relationship between a laser processed surface and a galvanometer mirror.
FIG. 3 is a schematic cross-sectional view of an essential part of a laser processing apparatus according to a second embodiment.
FIG. 4 is a diagram illustrating an example of a conventional laser processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2 Flexible substrate 2a Laser processing surface 2b Marker hole 3 Unwinding roll 4 Winding roll 5 Suction stage 5a Suction surface 6 Marker detector 7 Galvano mirror 7a, 7b Reflecting mirror 7c, 7d Rotation drive mechanism 8 Focus Adjustment lens 9 Laser oscillator 10 Control unit 20 Vertically lower region 30 Laser processing device 31 Spray nozzle 32 Compressor 33 Suction duct 34 Exhaust pump

Claims (6)

In a laser processing apparatus for removing a part of the thin film by irradiating the substrate on which the thin film is formed with a laser beam,
A laser processing surface of the substrate irradiated with the laser light is arranged vertically or vertically downward, and the laser processing surface is scanned on the laser processing surface by adjusting an irradiation position of the laser light on the laser processing surface. A laser processing apparatus, characterized in that a galvanometer mirror is disposed outside a vertically lower region of the laser processing surface and on a normal line at the center of the laser processing surface. An air blowing means that is disposed on one end side of the laser processing surface, blows compressed air from one end side to the other end side of the laser processing surface, and blows processing dust generated from the thin film to the other end side of the laser processing surface. When,
A suction unit that is disposed on the other end side of the laser processing surface and sucks the processing dust together with the compressed air blown by the air blowing unit;
The laser processing apparatus according to claim 1, comprising: The said air blow means is arrange | positioned at the end point side when scanning the said laser beam, and the said attraction | suction means is arrange | positioned at the start point side when scanning the said laser beam. Laser processing equipment. In the laser processing method of removing a part of the thin film by irradiating the substrate on which the thin film is formed with laser light,
A laser processing surface of the substrate is disposed vertically or vertically downward, and a galvano mirror disposed outside the vertically lower region of the laser processing surface disposed vertically or vertically downward and on the normal line of the center of the laser processing surface is used. And irradiating the laser processing surface with the laser beam. When removing a part of the thin film by irradiating the laser beam, compressed air is blown from one end side to the other end side of the laser processing surface, and the processing dust generated from the thin film is removed from the laser processing surface. The laser processing method according to claim 4, wherein the processing dust is blown off to the end side and the processing dust is sucked together with the compressed air on the other end side of the laser processing surface. 6. The laser processing method according to claim 5, wherein the compressed air is blown from an end point side when the laser beam is scanned toward a start point side when the laser beam is scanned.

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