JP2729270B2 - Laser processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method for processing a workpiece by irradiating the workpiece with a laser beam, and more particularly, to a simple and accurate processing of the workpiece in a short time. Laser processing method.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a photovoltaic device, a thin film transistor (TFT), and the like, a laser processing method of processing a workpiece by irradiating the workpiece with a laser beam has been used.

In processing a workpiece with laser light as described above, conventionally, as shown in FIG. 1, a laser beam emitted from a laser device 10 is spot-shaped by an optical system 2 such as a lens. The laser beam condensed in such a manner is irradiated on the workpiece 30 and the laser beam or the workpiece 30 is scanned.
Various shapes have been processed on the workpiece 30.

For example, when manufacturing a photovoltaic device 5 used for a dial 4a of a wristwatch 4 as shown in FIGS. 2A and 2B, as shown in FIG. The laser beam condensed as described above is irradiated onto the metal electrode 32 formed on the metal electrode 32 so that the metal electrode 32 is removed. The laser beam is scanned as shown in FIG. After processing the shape corresponding to the dial 4a in order, a semiconductor layer 33 for performing photoelectric conversion is formed on the metal electrode 32 as shown in FIG. Also, the laser beam condensed as described above is irradiated, and this laser beam is scanned in the same manner as in the above case, and the dial 4
Processing of the shape corresponding to a is performed in order, and then, FIG.
As shown in (C), a light-transmitting surface electrode 34 made of ITO or the like is formed on the semiconductor layer 33, and the laser light focused on the surface electrode 34 as described above. The laser beam is scanned in the same manner as described above to sequentially process the shape corresponding to the dial 4 a on the surface electrode 34, and to form the shape corresponding to the dial 4 a on the substrate 31. A plurality of photovoltaic devices 5 were manufactured.

However, it is not necessary to scan the laser beam thus focused on the metal electrode 32, the semiconductor layer 33, and the surface electrode 34 to form a shape corresponding to the dial 4a one by one. Since the area is large and the shape of the pattern is complicated, the productivity is extremely troublesome and the productivity is significantly deteriorated. In addition, when the laser beam is scanned in a complicated manner corresponding to the shape of the dial 4a as described above, A scan shift causes a defective product or the like, a control mechanism for controlling the scanning of the laser beam becomes complicated, the apparatus becomes large, and processing of different shapes on the workpiece 30 is performed. This is also very difficult, and there are problems such as high cost.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a photovoltaic device, a TFT, or the like, in which a laser beam is irradiated onto a workpiece to form a desired shape on the workpiece. It is an object of the present invention to solve the above-mentioned problems in the above, and in performing processing of various shapes by irradiating a laser beam onto a workpiece, the processing can be performed easily in a short time, and accuracy is improved. It is an object of the present invention to stably perform good processing, not to increase the size of an apparatus, and to easily perform processing of different shapes on a workpiece. It is.

[0007]

In the laser processing method according to the present invention, in order to solve the above-mentioned problems, a laser beam is guided to a mask member having a plurality of light-shielding portions of a required shape. When the laser light that has passed through the member is projected onto the workpiece by the projection optical system, and the workpiece is processed by the laser light while leaving a projection portion corresponding to the light-shielding portion, the irradiation position of the laser light is changed. The mask is fixed and the workpiece is processed by moving the mask member and the workpiece in directions opposite to each other.

When the workpiece is processed in this manner, it is not necessary to scan the laser beam according to the shape to be processed as in the related art, and the processing corresponding to the shape of the light shielding portion formed on the mask member is collectively performed. It is possible to process the desired shape on the workpiece in a short time and easily.
There is no shift during scanning, and accurate processing can be performed. Also, by changing the shape of the light shielding part formed on the mask member, processing with various shapes on the workpiece can be easily performed. Become.

Further, in the laser processing method according to the present invention, the irradiation position of the laser beam is fixed, and the processing of the workpiece is performed by moving the mask member and the workpiece in directions opposite to each other. As in the case of changing the irradiation position, there is no need to complicate the apparatus due to complicated control of the position for performing accurate projection, and a light-shielding portion formed on a workpiece on a mask member. In the case of performing a plurality of processes while leaving portions corresponding to the above, the movement of the mask member and the workpiece can be efficiently performed, and efficient processing can be performed in a short time.

Here, as the above-mentioned laser beam, various laser beams such as a gas laser and a solid-state laser can be used, and a laser beam having an appropriate wavelength and energy according to a material of a workpiece to be processed. Will be used. In addition, in order to prevent unevenness in processing of the workpiece, a laser beam having a small change in energy distribution is used, or before the laser beam is guided to the mask member,
It is preferable that the intensity of the laser beam is homogenized by homogenizing means such as a homogenizer.

The mask member is made of a material that is not easily deteriorated by a laser beam. For example, a metal member having a light-shielding portion of a required shape, quartz glass, or the like may be used. It is possible to use a material in which a light-shielding portion of a required shape is formed of a dielectric material such as chromium oxide that blocks laser light on a light-transmitting material such as.

[0012]

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

(Embodiment 1) In a laser processing method according to this embodiment, as shown in FIG. 5, a laser device 10 that oscillates a laser beam such as an excimer laser emits a laser beam, and the laser beam is converted into a slit or a laser beam. After passing through a beam shaping optical system 11 constituted by a beam expander to form a predetermined cross-sectional shape, this laser beam is passed through a beam homogenizing optical system 12 such as a homogenizer to form a laser beam having a predetermined cross-sectional shape. Are made to have a uniform intensity distribution.

The laser light having a predetermined cross-sectional shape and having a uniform intensity is reflected by the reflecting mirror 13, and the laser light is guided to the mask member 20 having the light-shielding portion 21 having a required shape. The laser beam is shielded by the light-shielding portion 21 of the mask member 20, and the laser beam that has passed through the mask member 20 is projected and imaged on the workpiece 30 by the projection optical system 14 including a lens or the like to form the workpiece 30. Irradiated upward, the projection 30 corresponding to the light-shielding portion 21 not irradiated with the laser light is left, and the workpiece 30 around it is processed by the laser light.

In the laser machining method according to the present embodiment, the X-axis is used to move the workpiece 30 in a plane.
-XY table 4
1 controls the movement of the workpiece 30 and the movement of the mask member 20 by the control device 40, and controls the timing at which laser light is emitted from the laser device 10 by the control device 40. As described above, a plurality of processings are sequentially performed, and the processing state is observed by the monitor 42.

Next, the case where the photovoltaic device 5 used for the dial 4a of the wristwatch 4 as shown in FIGS. 2A and 2B by the laser processing method of this embodiment is specifically described. explain.

Here, the mask member 20 includes:
As shown in FIG. 6, the dial 4a is formed on a transparent quartz glass plate 22 by a dielectric such as chromium oxide which blocks laser light.
A plurality of light-shielding portions 21 corresponding to the shape are provided.

The laser light emitted from the laser device 10 as described above is passed through the beam shaping optical system 11 and the beam homogenous optical system 12 to shape the laser light into a predetermined cross-sectional shape and to form the laser light. The intensity distribution is homogenized, and the laser light having a predetermined cross-sectional shape and homogenized intensity is reflected by the reflection mirror 13, and the laser light is guided to the mask member 20.

Here, in this embodiment, as shown in FIG.
The laser beam is made to be larger than one light-shielding portion 21 corresponding to the shape of the dial 4a provided in the laser beam, and this laser light is applied to the entire one light-shielding portion 21 and its surroundings. In addition, it is also possible to reduce the cross-sectional shape of the laser beam in order to increase the intensity of the laser beam. When the cross-sectional shape of the laser beam is smaller than one light shielding portion 21 provided on the mask member 20, for example, A laser beam is applied to a quarter of the light-shielding portion 21 and the periphery thereof. Or,
In order to improve the speed of laser processing, a plurality of light shielding portions 2
1 may be radiated to the periphery thereof.

The laser beam irradiated on the mask member 20 and passed through the mask member 20 as shown in FIG.
As shown in (A), the projection optical system 14 is used to project and form an image on a metal electrode 32 formed on a substrate 31. When the laser light is irradiated on the metal electrode 32 in this manner, the projected portion corresponding to the light shielding portion 21 is not irradiated with the laser light and the metal electrode 32 remains without being processed, while the metal electrode 32 around the metal electrode 32 remains. 32 is irradiated with a laser beam to remove the metal electrode 32, and the dial 4
Processing corresponding to the shape of a was performed at once.

After one processing corresponding to the shape of the dial 4a is performed on the metal electrode 32 in this manner,
As shown in FIG. 7, the XY table 41 is moved by the control device 40 to set the substrate 31 on which the metal electrode 32 is formed at a predetermined position, and the mask member 20 is inverted with respect to the substrate 31. The laser beam is emitted from the laser device 10 by the control device 40 in synchronization with the timing at which the light-shielding portions 21 provided on the mask member 20 are set at predetermined positions by moving the light-shielding portions 21 at the predetermined positions. Then, processing corresponding to the shape of the dial 4a is performed on the metal electrode 32 in the same manner as described above, and such operations are repeated many times, so that a large number of dials 4a are formed on the entire surface of the metal electrode 32. Processing corresponding to the shape was performed.
By doing so, it is not necessary to move the irradiation position of the laser beam, the movement range of the mask member 20 and the substrate 31 can be reduced, and the metal electrode 3 formed on the substrate 31 can be reduced.
2 can be continuously processed efficiently.

After the entire surface of the metal electrode 32 has been processed in accordance with the shape of the large number of dials 4a, the photoelectric conversion is performed on the metal electrode 32 as shown in FIG. 8B. Is formed, and the semiconductor layer 3 is formed.
3, in the same manner as in the case of the metal electrode 32 described above, processing corresponding to the shape of the dial 4 a is sequentially performed.
Thereafter, as shown in FIG. 8C, a light-transmitting surface electrode 34 made of ITO or the like is formed on the semiconductor layer 33, and the surface electrode 34 is formed in the same manner as described above. Then, processing corresponding to the shape of the dial 4a is sequentially performed, and a large number of photovoltaic devices 5 having a shape corresponding to the dial 4a are formed on the substrate 31, and the photovoltaic device thus formed is formed. 5 was punched out.

In this manner, the metal electrode 32 and the semiconductor layer 33 are scanned while scanning the laser beam condensed as in the prior art.
As compared with the case where the processing corresponding to the shape of the dial 4a is performed one by one on the surface electrode 34 and the surface electrode 34, the above-described photovoltaic device 5 can be manufactured easily in a short time, and the productivity is reduced. Significantly improved, the processing accuracy was increased, and the occurrence of defective products was reduced.

In this embodiment, the laser beam projected and imaged as described above is only irradiated once on the workpiece 30. When the electrode 32, the semiconductor layer 33, and the surface electrode 34 cannot be sufficiently processed, the workpiece 30 may be continuously irradiated with laser light a plurality of times,
As shown in FIG. 9, two laser beams projected and imaged as described above are irradiated at a time at adjacent positions on the workpiece 30, and after performing preliminary processing with one of the laser beams, a mask is formed. It is also possible to move the member 20 and the workpiece 30 and to perform the main processing on the portion preliminarily processed as described above by the other laser beam.

(Embodiment 2) The laser processing method of this embodiment is also substantially the same as that of Embodiment 1 described above, and as shown in FIG. Optical system 12
, And the laser beam is reflected by a reflection mirror 13 to guide the laser beam to a mask member 20 provided with a light-shielding portion 21 having a required shape. The laser light is shielded by the light-shielding portion 21 in FIG. 1, and the laser light that has passed through the mask member 20 is projected and imaged on the workpiece 30 by the projection optical system 14 and radiated onto the workpiece 30. So that the projection part corresponding to the light shielding part 21 which is not
The workpiece 30 around it is processed by laser light.

The workpiece 30 is moved by an XY table 41 which moves in a plane,
The movement of the workpiece 30 and the movement of the mask member 20 by the XY table 41 are controlled by the control device 40, and the timing at which laser light is emitted from the laser device 10 is controlled by the control device 40. The processing state of the workpiece 30 is observed by the monitor 42.

In the laser processing method according to the second embodiment, since a polycrystalline silicon TFT is manufactured, FIG.
As shown in FIG. 0, a workpiece 30 having an amorphous silicon thin film 35 formed on a substrate 31 is used, and the workpiece 30 is set in a chamber 50 by being heated by a heater 51. The atmosphere in the chamber 50 is controlled by a gas control device 52 so that the inside of the chamber 50 is vacuum or an inert gas atmosphere such as nitrogen, argon, helium, or neon.

Then, the laser beam that has passed through the mask member 20 as described above is projected and imaged on the amorphous silicon thin film 35 provided on the substrate 31 by the projection optical system 14, and is irradiated on the amorphous silicon thin film 35. Then, the projection part corresponding to the light shielding part 21 not irradiated with the laser beam is left, and the amorphous silicon in the other part is crystallized.

Thereafter, X-
The movement of the Y table 41 and the mask member 20 is controlled, and the workpiece 30 and the mask member 20 are set at predetermined positions. In this state, the laser light passing through the mask member 20 is projected onto the projection optical The system 14 projects and forms an image on the amorphous silicon thin film 35 at a position newly set, leaving a projection portion corresponding to the light-shielding portion 21 not irradiated with the laser beam, and crystallizing the amorphous silicon in the other portions. By repeating such operations, the amorphous silicon thin film 35 provided on the substrate 31 is crystallized in a desired plane pattern, and a polycrystalline silicon TFT having a desired pattern is manufactured.

When a polycrystalline silicon TFT is manufactured in this way, it can be manufactured in a shorter time and easily than in a conventional case in which a condensed laser beam is scanned to form a polycrystalline silicon TFT having a required pattern. In addition, the productivity is remarkably improved, the processing accuracy is increased, and the occurrence of defective products is reduced.

In this embodiment, the substrate 31
The polycrystalline silicon TFT is manufactured by crystallizing the upper amorphous silicon thin film 35 in a desired pattern. However, according to the method of this embodiment, a compound semiconductor thin film such as GaAs or DLC (diamond-like carbon) is used.
Can also be used for recrystallization and the like.

[0032]

As described above in detail, in the laser processing method of the present invention, a laser beam is guided to a mask member having a plurality of light shielding portions, and the laser beam passing through the mask member is projected by a projection optical system. Projected on the workpiece,
In processing the workpiece with the laser light while leaving the projection portion corresponding to the light-shielding portion, the irradiation position of the laser light is fixed, and the mask member and the workpiece are moved in opposite directions. As described above, the processing of the workpiece is performed, so that it is not necessary to scan the laser light according to the shape to be processed as in the related art, and the processing corresponding to the shape of the light shielding portion formed on the mask member can be performed collectively. As a result, processing of a desired shape on a workpiece can be performed easily in a short time, there is no deviation during scanning, and accurate processing can be performed, and the shape of a light shielding portion formed on a mask member can be changed. Simply by doing so, it became possible to easily perform processing into various shapes on the workpiece.

In the laser processing method according to the present invention, the irradiation position of the laser beam is fixed as described above,
Since the processing of the workpiece is performed by moving the mask member and the workpiece in directions opposite to each other, it is troublesome to control the position for performing accurate projection, such as when changing the irradiation position of laser light. The mask member and the workpiece are moved when performing a plurality of processes while leaving a portion corresponding to the light shielding portion formed on the mask member on the workpiece without causing the apparatus to be complicated. Has been performed efficiently, and efficient processing can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a state in which processing is performed on a workpiece by a conventional laser processing method.

FIG. 2 is a plan view of a wristwatch using a photovoltaic device for a dial portion and a photovoltaic device used for a dial portion.

FIG. 3 is an explanatory view showing a process of manufacturing a photovoltaic device used for a dial portion by a conventional laser processing method.

FIG. 4 is an explanatory plan view showing a state in which processing is performed on a workpiece by a conventional laser processing method in accordance with the shape of a photovoltaic device used for a dial portion.

FIG. 5 is a schematic explanatory view showing a state in which a laser beam is projected and imaged on a workpiece by laser processing in the first embodiment of the present invention to perform processing;

FIG. 6 is a plan view of a mask member used when manufacturing the photovoltaic device used for the dial portion by the laser processing method in the first embodiment.

FIG. 7 is a diagram illustrating a method of manufacturing a photovoltaic device used for the dial portion by the laser processing method according to the first embodiment. FIG. 3 is an explanatory plan view showing a state in which processing is performed.

FIG. 8 is a schematic explanatory view showing a step of manufacturing a photovoltaic device used for the dial portion by the laser processing method in the first embodiment.

FIG. 9 shows two laser beams projected and imaged at adjacent positions on a workpiece when a photovoltaic device used for the dial portion is manufactured by the laser processing method in the first embodiment. FIG. 4 is a schematic explanatory view showing a state in which irradiation is performed at a time and preliminary processing and main processing are performed.

FIG. 10 is a view showing an example in which a laser beam is projected and imaged on a workpiece by a laser processing method according to a second embodiment of the present invention, and an amorphous silicon thin film on the workpiece is crystallized in a desired pattern to manufacture a polycrystalline silicon TFT. FIG. 4 is a schematic explanatory diagram showing a state in which

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laser apparatus 12 Beam homogenous optical system (homogenizing means) 14 Projection optical system 20 Mask member 21 Shielding part 30 Workpiece 31 Substrate 32 Metal electrode 33 Semiconductor layer 34 Surface electrode 35 Amorphous silicon thin film 40 Control device 41 XY table

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01S 3/00 (56) References JP-A-4-302129 (JP, A) JP-A-6-302 297177 (JP, A) JP-A-7-84357 (JP, A) JP-A-6-236020 (JP, A) JP-A-7-219243 (JP, A) JP-A-6-120113 (JP, A) JP-A-6-43628 (JP, A)

Claims (1)

(57) [Claims] 1. A laser beam is guided to a mask member on which a plurality of light-shielding portions of a required shape are formed, and the laser beam passing through the mask member is projected onto a workpiece by a projection optical system.
In processing a workpiece with the laser light while leaving a projection portion corresponding to the light-shielding portion, irradiation of the laser light is performed.
With the firing position fixed, the mask member and the workpiece
A laser processing method wherein the workpiece is processed by moving the workpiece in the opposite direction .