JPH02280985A - Laser beam machine - Google Patents

Abstract

PURPOSE:To precisely control the machining position with YAG laser beam by dividing the laser beam form a second laser beam source scanned together with the laser beam from a first laser beam source and precisely measuring this. CONSTITUTION:The laser beams from the YAG laser beam source (the first) 1 and the He-Ne laser beam source (the second) 2 are overlapped on the same beam path. This laser beam is scanned on the table 11 in two dimensions. In the scanned laser beam, the laser beam from the first laser beam source 1 is transmitted with a beam divider and transmitted onto the table 11 and the laser beam from the second laser beam source 2 is reflected. The shifting quantity of the reflected laser beam from the second laser beam source 2 is precisely measured. The measured laser beam shifting quantity and the command are inputted to control means and the laser beam is scanned. By this method, shift of the position of the laser beam can be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing apparatus, and more particularly to a fine laser processing apparatus that can be applied to the modification of large-capacity memory devices.

[Conventional technology]

As a conventional technique, for example, as shown in Journal of the Japan Society for Plasticity (Plasticity and Processing), Vol. 27, No. 307, P, 928-P, 933, a laser beam scanning device with an encoder provided on the laser beam scanning means is used. There is processing equipment.

Next, a conventional laser processing apparatus will be described in detail with reference to the drawings. FIG. 2 is a perspective view showing a conventional laser processing device. The laser processing apparatus shown in FIG. 2 includes a YAG laser light source 30, a beam expander 31, an xy stage 32, an A y-axis vertical/valley encoder 34 and mirrors 35 provided on the x-axis and y-axis of the xy stage 32, respectively. and mirror 3
6, a focusing lens 37, a table 38, an A command unit 41 that issues a command, and an X-axis controller 4 that calculates the difference between the signal from the command unit 41 and the signals from the y-axis and y-axis counters 39 and 40 and outputs a drive command to the xy stage 32.
2 and an X-axis controller 43.

The laser light emitted from the YAG laser light source 30 is collimated into parallel light by the beam expander 31, and
The light is incident on a mirror 35 placed on the axis. The laser light is
The light is further reflected by the mirror 35 at right angles within the xy plane, enters a mirror 36 placed on the y axis, and is reflected at right angles to the xy plane. Next, the laser beam enters the condensing lens 37 and focuses on the table 38. At this time, the mirror 35
and 36, the laser beam on the table 38 is scanned within the table plane, and the workpiece on the table 38 is processed. Mirrors 35 and 36
This position is determined by the position, and this position is measured by linear encoders 33 and 34 installed on each axis of the xy stage 32.

[Problem to be solved by the invention]

The conventional laser processing apparatus described above determines the position of the laser beam on the workpiece, that is, the processing position, by measuring the moving distance of the mirrors 35 and 36 for scanning the laser beam. For this reason, the pitching of the xy stage 32,
Mirrors caused by yawing and rolling35.36
There is a drawback that the position of the laser beam on the table 38 is shifted due to the inclination of the table 38. Assuming that the distance between the mirror 36 and the table 38 is 500 mm and the tilt of the mirror 36 due to pitching or the like is 10 seconds, the positional deviation of the laser beam on the table 38 reaches as much as 24 μm.

Further, since the distance between the mirrors 35, 36 and the table 38 is large, there is a drawback that the positional deviation of the laser beam due to air drift between them is large.

Although the demand for high-precision laser processing is increasing, such as when performing laser trimming of large-capacity memory devices, the above-mentioned drawbacks are fatal to high-precision laser processing.

[Means to solve the problem]

The laser processing apparatus of the present invention includes first and second laser light sources, combining means for superimposing the laser lights from the first and second laser light sources on the same optical path, and a workpiece placed thereon. a table; a scanning means for two-dimensionally scanning the laser beams superimposed by the combining means on the table; and a scanning means for transmitting the laser beam from the first laser light source among the laser beams scanned by the scanning means. a light splitter that reflects the laser light from the second laser light source that is sent onto the table; and a measuring means that measures the amount of movement of the laser light from the second laser light source that is reflected by the light splitter. and a control means for inputting the movement amount of the laser beam measured by the measuring means and a command to drive the scanning means to scan the laser light according to the command.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

The laser processing apparatus shown in FIG. 1 includes a YAG laser light source 1, a He-Ne laser light source 2 arranged at right angles to the YAG laser light source 1, and
A beam splitter 5 that overlaps the optical axis of the G laser beam 3 and the optical axis of the He-Ne laser beam 4 emitted from the He-Ne laser light source 2, and a beam expander 6 that expands the beam diameter of the overlapped laser beams. Then, the laser beams overlapped by the xy stage 7 and the beam splitter 5 are input, and the laser beams are reflected at right angles in the xy plane by the mirror 8 installed on the X axis of the Xy stage 7 and the mirror 8. incident xy
Mirrors installed on the y-axis of stage 7 and mirror 9
a condenser lens 10 into which laser light reflected perpendicularly to the xy plane formed by the xy stage 7 is incident; a table 11 on which the light condensed by the condenser lens 10 scans;
It is installed between the condensing lens 10 and the table 11, and the YAG
a beam splitter 12 that transmits the laser beam 3 and reflects the He-Ne laser beam 4 at right angles;
An xy stage 13 installed in a plane perpendicular to the optical axis of the He-Ne laser beam 4 reflected at right angles by
A four-part sensor 14 installed on the y-stage, an X-axis near encoder 15 and a y-axis near encoder 16 that measure the y-axis of the xy stage 13 and the driving distance of the y-axis,
X-axis linear encoder 15 and y-axis linear encoder 1
an X-axis counter 17 and a y-axis counter 18 that count the outputs of the
The difference between the signal from the command unit 19 and the signal from the command unit 19 is calculated, and xy
X-axis controller 2 outputs drive commands to stage 7
0 and an X-axis controller 21.

The YAG laser light source 1 and the He-Ne laser light source 2 are arranged at right angles to each other, and their respective emitted lights enter a beam splitter 5, are superimposed on the same optical axis, and enter a beam expander 6. The laser beam is collimated into parallel light, enters a mirror 8 on an xy stage 7, is reflected at right angles, and enters a mirror 9. Here, it is reflected at right angles to the xy plane formed by the xy stage 7 and enters the condenser lens 10.

YAG laser light and He-Ne at beam splitter 12
The YAG laser beam is separated into laser beams, passes through a beam splitter 12, and is focused on the table 11.

The He-Ne laser beam is reflected at a right angle by the beam splitter 12, and enters a four-part sensor 14, which is placed on an xy stage 13 and has four sensing elements arranged in a square shape to detect the amount of laser beam. do. The xy stage 13 is driven so that the sensing signals of each divided sensing element of the 4-split sensor 14 are equal to each other, and the position of the laser beam is precisely detected by measuring the amount of drive of the xy stage 13 at this time. . By driving the xy stage 7 and moving the mirrors 8 and 9, the Y
The table 11 is scanned with an AG laser beam. At this time H
The e-Ne laser beam is scanned on the xy stage 13.

The four-divided sensor 14 on the xy stage 13 outputs a drive command to the drive section of the xy stage 13 so that the output of each of the four divided sensors is always equal, and the He
- Follows the Ne laser beam.

〔Effect of the invention〕

The laser processing apparatus of the present invention splits the laser light from the second laser light source scanned together with the laser light from the first laser light source that scans the workpiece, and splits the laser light from the split second laser light source into two parts. By precisely measuring the laser beam from the laser light source, it is possible to correct the positional deviation of the laser beam due to aberrations of the condenser lens and the positional deviation of the laser beam due to air drift between the mirror and the table. This has the effect of allowing precise control.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a perspective view showing a conventional laser processing apparatus. 1-Y AG laser light source, 2-He-N e laser light source, 5.12...beam splitter, 7.13...
・xy stage, 10... condensing lens, 11... table, 14... 4-split sensor, 15... X-axis near encoder, 16... y-axis near encoder, 17
, 18... Counter, 19... Command unit, 20.21
···controller.

Claims (1)

[Claims] a first and a second laser light source, a combining means for overlapping the laser beams from the first and second laser light sources on the same optical path, a table on which a workpiece is placed, and a combining means for overlapping the laser beams from the first and second laser light sources; scanning means for two-dimensionally scanning the combined laser beams on the table; and scanning means for scanning the laser beams from the first laser light source among the laser beams scanned by the scanning means and transmitting the laser beams from the first laser light source onto the table. The light from the second laser light source includes a reflecting light splitter, a measuring means for measuring the amount of movement of the laser light from the second laser light source reflected by the light splitter, and a laser beam measured by this measuring means. 1. A laser processing apparatus comprising: a control means that inputs a light movement amount and a command to drive the scanning means to scan the laser beam according to the command.