JPS6052822A - Laser device - Google Patents

Abstract

PURPOSE:To enable easy positioning with high accuracy with a laser device which irradiates laser light through a prescribed optical guide path onto a substrate and providing means for decreasing the copy lens of the laser light to the optical guide path. CONSTITUTION:The laser light from a laser oscillator 1 is passed through a deflection prism 2 and a quarter-wave plate 3 and after the direction thereof is changed by a prism 4 on an X-stage 18, the light is conducted onto a Y stage 19 and passes through an aperture 5. About 99% laser light is reflected by a half mirror 6 and is irradiated via a mechanical shutter 7 and a projecting lens 8 onto the silicon substrate 10 in a chamber 9. The control (Z-axis direction) of the position and spot diameter of the laser light on the substrate 10 is accomplished by conducting the light transmitted through the mirror 6 and reflected from the substrate 10 to the 1st mirror 11, a condenser lens 12, the 2nd mirror 13 and a microscope lens 14 and detecting the pattern thereof, i.e., the pattern of a positioning mark with a television camera 15. A scattering plate 20 is provided between the mirror 6 and the prism 4 in the stage of positioning in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to a laser device, and more particularly to a laser CVD device capable of highly accurate positioning of a substrate to be irradiated.

■ Explanation of conventional technology Laser CVD technology uses light energy in recent years to
It is attracting attention as one of the D technologies. In this method, a substrate such as a silicon substrate is placed in an atmosphere of monosilane (5IH4), etc., and an amorphous silicon film is selectively formed on the oxidized substrate by heating locally with an argon laser or the like. be.

Conventionally, a laser CVD apparatus has a configuration as shown in FIG. That is, the laser beam from the laser oscillator 1 passes through the inner prism 2 and 1/4 wavelength plate 3, has its direction changed by the prism 4 on the X stage 18, and is then guided onto the Y stage 19 where it is ablated. Approximately 99 beams of laser light are reflected by the bar 7 mirror 6 after passing through the shutter 5, pass through the mechanical shutter 7 and the projection lens 8, and are irradiated onto the silicon substrate 10 in the chamber 9. At this time, the position and spot diameter of the laser beam on the silicon substrate 10 are controlled (Z
Since control in the axial direction is extremely important, alignment marks are provided in advance on the silicon substrate 10, and the X stage 18, Y stage 19, and projection lens 8 are controlled during laser irradiation to adjust the spot.

This adjustment is performed using the silicon substrate 1 that has passed through the half mirror 6.
The reflected light from the first mirror 11, the condensing lens 12,
This is done by guiding the alignment marks to a second mirror 13 and a microscope lens 14, and detecting the pattern, that is, the pattern of alignment marks, with a television camera 15. Here, if the laser beam is used as a light source for creating this reflected light, a speckle pattern or the like is generated due to the scattered light of the incident light and the reflected light, or each other, and the alignment pattern becomes invisible as shown in Figure 3. , therefore, highly accurate positioning was difficult.

Therefore, a white light source 16 and a movable mirror 17 are further provided on the Y stage, and the movable mirror 17 is
Alignment was performed by moving the mirror so that white light was incident on half mirror A. However, with this method, the positioning accuracy decreases due to undesired heat generation and the difference in wavelength between the alignment light and the light used for CVD.
The device could not be realized.

(3) Object of the Invention An object of the present invention is to provide a laser device that does not have the above-mentioned drawbacks of the conventional laser device and can easily perform highly accurate positioning.

(4) Features of the invention A feature of the present invention is that in a laser device that irradiates laser light onto a substrate through a predetermined light guide path, a means for lowering a copy lens for the laser light is provided in the light guide path. Go to the laser device. This conversion means can be a scattering plate that distributes the phase of the laser beam at each point, such as a glass plate (ground glass) with a different thickness at each arbitrary point, a glass plate cut into a predetermined pattern, a mesh, especially a metal mesh. It is preferable to write something like this. Furthermore, it is preferable to vibrate this scattering plate to average out the phase disturbance.

(5) Effects of the Invention According to the present invention, extremely highly accurate positioning is possible using a laser beam used for processing. Furthermore, by vibrating the laser light scattering means, undesirable resolution unevenness is averaged out, so that a visually extremely clear alignment pattern image can be obtained.

(6) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a laser CVD apparatus according to an embodiment of the present invention.

As in the conventional example shown in FIG.
Its direction is changed by prism 4 on 8, and then Y
The laser beam is guided onto a stage 19, passes through an aperture 5, is reflected by a half mirror 6, passes through a mechanical shutter 7, a projection lens 8, and is irradiated onto a silicon substrate 10 in a chamber 9. At that time, the position and spot diameter of the laser beam on the silicon substrate 10 are controlled (z
For control in the axial direction, positioning marks are provided in advance on the silicon substrate 1o, and the spot is adjusted by controlling the X stage 18, Y stage 19, and projection lens 8 during laser irradiation.

This adjustment is performed using the silicon substrate 1 that has passed through the half mirror 6.
The reflected light from the first mirror 11, the condensing lens 12,
The pattern is guided to the second mirror 13 and the microscope lens 14, and the pattern, that is, the pattern of the alignment mark, is detected by the television camera 15. Here, a scattering plate 20 is provided between the half mirror 6 and the deflection prism 4 during alignment. Due to this scattering plate 20, the laser beam is not an incopy left beam, and the alignment pattern becomes as shown in FIG. 4, so that the apparent accuracy is greatly improved. Further, by moving the scattering plate 20 in a direction perpendicular to the laser beam, the scattering is further averaged and the visibility of the alignment pattern is further improved as shown in FIG.

The speed of this movement is one period of fluctuation of the surface of the scattering plate,
In other words, it is sufficient that the period of change at the same position does not flicker when visually observed, and if the scattering plate 20 is a metal mesh with a metal wire spacing of 300 μm or less, 20111
7 seconds or more is sufficient.

Note that a sufficient effect can also be obtained with a plastic net or the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional laser CVD apparatus, Fig. 2 is a schematic diagram of a laser CVD apparatus according to an embodiment of the present invention, Fig. 3 is an alignment pattern image when no scattering plate is used, and Fig. 4 5 is an alignment pattern image when a scattering plate is used, and FIG. 5 is an alignment pattern image when the scattering plate is vibrated. In the figure, 1... the oscillator, 2... deflection prism, 3... 174 wavelength plate, 4... prism, 5... aperture, 6... half mirror 17...
・Mechanical shutter, 8... Projection lens, 9...
Chamber, 10... Silicon substrate, 11... First mirror, 12... Condensing lens, 13... Second mirror, 14... Microscope lens, 15... Television camera, 18...X stage, 19...Y stage, 2o... scattering plate. Figure 3 Figure 4 Figure 5 Procedural amendment (method) % formula % 1. Indication of the case Original Patent No. 1.61576 of 1988 Name of the invention Laser device 3. Person making the amendment Relationship to the case Patent Applicant January 61, 1982 (shipping date) 5. Full text of the specification subject to amendment

Claims (1)

[Claims] A laser device that irradiates laser light onto a substrate through a predetermined light guide path, wherein the light guide path is provided with means for lowering a copy lens for the laser light.