JPS6380990A - Laser beam machine - Google Patents

Abstract

PURPOSE:To perform the laser beam machining with the large energy by regulating the pulse width of laser beam from a laser oscillator to the optional size using a shutter means and giving the laser beam with the prescribed pulse width to a work. CONSTITUTION:The pulse width of the laser beam from the laser oscillator 1 is regulated by the shutter 2 and afterward, projected on a metal electrode of a photoelectric converter 4 via an X scanner 6 and a Y scanner 5. Both scanners 6 and 5 mentioned above move the laser beam to an A axis and a Y axis. The shutter 2 controls the pulse width by control of a computer 3. Accordingly, a laser pulse having the small pulse width and the large energy is obtained by the opening and closing of the shutter 2. A YAG laser, etc., with a switch Q can be used for the laser oscillator 1. The laser beam machining of the metal electrode of a photoelectric conversion element which has been difficult so far can be performed easily by the titled machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing device that can irradiate a laser pulse with a small pulse width and high energy.

[Conventional technology]

Conventionally, when laser processing the metal electrode portion of a photoelectric conversion device, a YAG laser with a Q switch has been mainly used.

In the above-mentioned laser processing method, a spot-shaped beam is irradiated onto the workpiece, and this beam is scanned in the processing direction to form an opening in the form of a continuous chain of points. Therefore, the scanning speed of this laser beam,
The beam energy density required for processing interacts in a very subtle way with the thermal conductivity and sublimation properties of the workpiece.

[Problem that the invention seeks to solve]

For this reason, when selecting the correlation between the thermal conductivity, sublimation property, scanning speed, and beam energy density of the workpiece as processing conditions, it was difficult in practice because the selection had to be made within an extremely narrow range. .

For the above reasons, for example, when a photoelectric conversion element is a semiconductor to be quality-treated, in actual processing, the metal bridge material on the photoelectric conversion element reacts with the underlying photoelectric conversion element, creating a molten state. If the photoelectric conversion element is damaged or is irradiated with laser light, the irradiated area will crystallize and the electrical conductivity of the crystallized area will improve, causing leakage current. This resulted in deterioration of the characteristics of the photoelectric conversion device.

In view of this current situation, the inventors of the present invention have conducted intensive studies and found that it is easier to use a laser beam with a small laser pulse width and a large pulse energy, that is, to instantaneously irradiate a large amount of energy to the workpiece. They discovered that processing conditions can be determined based on the process.

The present invention has been made based on the above knowledge, and it is possible to obtain a pulse like the part B of the pulse oscillation waveform shown in FIG. 1 by passing a laser beam from a laser light source through a shutter. In order to obtain a laser pulse (A) with a small pulse width and high energy, parts (C) and (D) are removed by opening and closing a shutter,
The purpose is to instantaneously apply a large amount of energy to the workpiece.

[Means for Solving the Problems] The present invention is a laser processing device characterized in that a laser beam from a laser oscillator is passed through a shutter means whose pulse width can be adjusted to an arbitrary size. This is a laser processing device that can obtain a laser beam with a predetermined pulse width by passing a laser beam from a laser oscillator through a shutter for reducing the pulse width of the laser beam.

The laser processing apparatus of the present invention will be explained in detail below.

As the laser oscillator, a Q-switched YAG laser and an excimer laser that emit light at a wavelength of 1.06 μm or 0.53 μm can be used.

In order to shorten the pulse width to a predetermined time (A), the shutter means processes the repetition frequency and pulse width values of the laser beam oscillated from the laser oscillator and the desired pulse width by a computer to shorten the pulse width of the irradiated laser beam. This is to control the

The shutter may be a mechanical shutter that opens and closes mechanically as long as it can be controlled so that the laser beam can be irradiated for a predetermined period of time, or a shutter that uses an electrical method to control the light. It may be.

After passing through the shutter means, the laser beam from the laser oscillator is irradiated onto the workpiece by a method suitable for the workpiece.

〔Example〕

Example FIG. 2 shows one embodiment of the present invention.

The laser oscillator (1) has a Y with a 1.06 μm Q switch.
AG laser (frequency 1~50H2) beam diameter 10~10
0 pm φ e.g. 50 μm φ, average output 0.1-50
W For example, the average output of each laser beam on the processed surface is 0.5 to I
W), frequency 5K) I2) pulse width 200ns
The laser beam was oscillated.

The shutter (2) uses a mechanical shutter, and the pulse width is controlled by the computer (3) to 100.
It was opened and closed to make it ns. In the figure, 5 and 6 are an X scanner and an X scanner for moving the laser beam on the workpiece in the X-axis direction and the X-axis direction, respectively.

The laser beam from the laser oscillator had a pulse width of 100 ns using a shutter, and then was irradiated onto the metal electrode of the photoelectric conversion device (4) to perform laser processing.

That is, after forming a transparent conductive film mainly composed of tin oxide doped with a halogen element on a 1010Cl1X10 glass plate to a thickness of 1000 mm using the plasma CVD method, this transparent conductive film was coated with a YAG laser. (530nm)
The spot diameter was controlled to 20 μmφ by a microcomputer, and the laser beam was irradiated from the coating side.
A first opening of 0 μm was formed. After that, a P-type amorphous semi-solid layer (
An I-type amorphous semiconductor layer (silicon semiconductor, 0.6 μm) and an N-type microcrystalline semiconductor layer 5jxC+-x x =0.9100 were formed. A second groove was formed only in the PIN semiconductor layer by a conventional method using an excimer laser (KrF laser, wavelength 248r+m 2 ) on the formed PIN semiconductor. Furthermore, rTO is applied on the semiconductor layer.
(Mixture of indium oxide and tin oxide) Film 1200
A metal electrode consisting of 2,500 people and an aluminum film was formed.

The above laser beam is applied to the metal electrode with a beam size of 50μ.
mφ and a scanning speed of 40 (!II/min) to form the third groove. The third groove formed as a result allows only the metal electrode to be removed without damaging the underlying semiconductor layer. did it.

Figure 3 shows the pulse oscillation waveform (7) of the conventional Q-switched laser beam and the change in reflectance of the metal electrode during laser irradiation (
8). There is a point (E) where a change in reflectance begins to appear at the same time as laser irradiation and a point (F) where a rapid change in reflectance begins to appear.

From the above and the fact that when the metal electrode melts and the reflectance increases, it absorbs almost no laser light, it is clear that it is necessary to give the energy necessary for processing before the reflectance increases. . In other words, when irradiating a laser beam with a pulse waveform like that of the present invention, the energy necessary for processing can be applied to the metal electrode before the reflectance changes rapidly, as can be seen from the waveform. This makes it easier to determine processing conditions.

Comparative Example A metal electrode was created in the same manner as in the example, and a laser beam was oscillated on the metal electrode using the same YAG laser as used in the example, with a frequency of 5 and a pulse width of 100 ns, and the shutter was activated. The metal bridge was irradiated directly without passing through it.

As a result, when compared with the case where the pulse width was set to 100 ns using a shutter, there were processed parts and unprocessed parts.

〔Effect of the invention〕

According to the present invention, by using a shutter means, it is possible to obtain a laser pulse with a small pulse width and high energy, so that it is now possible to easily process the metal electrodes of photoelectric conversion elements, which was difficult in the past. Ta.

Furthermore, since the pulse width can be changed by setting the opening/closing time of the shutter, processing conditions can be easily selected.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a pulse oscillation waveform of a laser with a Q switch. FIG. 2 is an explanatory diagram showing the laser processing apparatus of the present invention. FIG. 3 is an explanatory diagram showing the pulse oscillation waveform of the Q-switched laser and the change in reflectance of the metal electrode when irradiated with the laser light of the Q-switched laser. B... Pulse width of the present invention 1... Laser oscillator 2... Shutter 3... Computer 4... Photoelectric conversion device

Claims (2)

[Claims] (1) A laser processing device characterized in that a laser beam from a laser oscillator is passed through a shutter means whose pulse width can be adjusted to an arbitrary size. (2) A laser processing apparatus according to claim (1), wherein the laser oscillator is a Q-switched YAG laser.