JPS6356383A - Control system for laser beam processing position - Google Patents

Abstract

PURPOSE:To reduce an initial cost by providing a slit aperture for imaging laser light onto a substrate to be worked and making the rough adjustment and fine adjustment respectively of a laser beam processing position by an X-Y table and the slit aperture. CONSTITUTION:The slit aperture 31 for imaging the laser light which is emitted from an oscillator 51 and reflected by a mirror 52 is disposed to the X-Y table 41 which carries the substrate 11 to be worked and is moved in X-axis and Y-axis directions by driving motors 44, 45. A control device determines the difference from the current X-Y coordinates in relation to the command X-Y coordinates applied thereto via a CPU from the outside and inputs the coarse moving quantity of the X-Y stage 41 and the fine adjustment moving quantity of the slit aperture 31 to the motors 44, 45 and slit driving part 3 respectively. The inexpensive device is simply required to make the adjustment of the X-Y stage 41 by the above-mentioned method; therefore, the initial cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a laser processing position control method, and in particular, a method for controlling the position of a laser processing substrate, in which a substrate to be processed is placed on an XY stage, and a laser beam irradiated through a slit opening is directed onto the substrate to be processed using a lens. The present invention relates to a laser processing position control method for a laser processing device that performs fine processing by forming an image.

Prior Art Conventionally, in laser processing equipment that cuts wiring in semiconductor wafers with laser light or cuts defective parts (short-circuit parts) of photomasks with laser light, when the workpiece is minute, the workpiece The XY stage, which performs positioning by placing and moving the laser beam, must be extremely precise with respect to the laser machining spot.

Ultra-precision XY stages used for such applications include types that have a fine movement XY stage for precise positioning on a coarse movement XY stage with low accuracy, and types that have a fine movement
Some devices have been put into practical use that allow ultra-precise positioning using only a Y stage.

In such conventional laser processing equipment, in the type in which a fine movement XY stage is provided on a coarse movement XY stage, the XY stage mechanism is complicated due to the two-stage structure.
This method has the disadvantage of high cost because it is necessary to prepare a control device for the fine movement XY stage. Also, one XY
If ultra-precise positioning is achieved using only a stage, the XY stage mechanism is difficult to manufacture and expensive.

In ultra-precision laser processing using these conventional XY stages, the current upper limit is processing of several points per second.

Purpose of the Invention The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional stage.It is possible to perform high-speed laser processing while guaranteeing the accuracy of the laser processing position, and to manufacture an XY stage at a low cost. The objective is to provide a laser processing position control system that allows for

Composition of the Invention The laser processing position control system according to the present invention is a laser processing method for a laser processing apparatus having an XY stage on which a substrate to be processed is placed and a slit opening for focusing a laser beam onto the substrate to be processed. The position control method performs rough adjustment of the laser processing position by moving the XY stage in parallel on a plane perpendicular to the laser beam, and moves the slit opening in parallel on a plane perpendicular to the laser beam. The laser processing position is finely adjusted by moving the upper part in parallel.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, one embodiment of the present invention is shown in a central processing unit (hereinafter referred to as CP).
tJ) 1, a controller 2 that adjusts the laser processing position, a slit drive section 3, an XY stage section 4 on which a substrate to be processed 11 is placed, and drivers 5 to 10.

Controller 2 has comparators 21 and 22 and counter 2
3 and 24, the current coordinates inputted by the X-axis position pulse 46 and Y-axis position pulse 47 from the XY stage section 4 are compared with the command coordinates inputted from the CPU 1 via the pass line 25, and the comparator 21, 22, and the comparators 21, 22 send the amount of movement to each driver 5-10 according to the comparison result.

The slit driving unit 3 adjusts the slit width using knife blades 36 to 39, and also moves the slit along the X axis.

A driving motor 3 for moving the slit opening 31 to move in the Y-axis direction and the knife blades 36 to 39, respectively.
2 to 35.

The drive motors 32 to 35 are DC motors equipped with encoders, which are driven by drivers 5 to 8, respectively, and move the knife blades 36 to 39, respectively, so as to keep the slit dimensions constant and move the slits perpendicular to the laser optical axis. The slit can be moved in parallel on a plane.

The XY stage section 4 includes an XY stage 41 on which the substrate 11 to be processed is placed, laser length measuring devices 42 and 43 attached to the XY stage 41, and
It is comprised of drive motors 44 and 45 for moving in the Y-axis direction. The drive motors 44, 45 are each driven by a driver 9.10. Further, the laser length measuring devices 42 and 43 calculate the current coordinates of the XY stage 41, and send the current coordinates to the controller 2 using an X-axis position pulse 46 and a Y-axis position pulse 47.

FIG. 2 is a schematic diagram of an embodiment of the present invention. In the figure, a laser beam emitted from a laser oscillator 51 is reflected by a laser mirror 52, passes through a slit opening 31 moved by a slit driving unit 3, and is imaged onto a substrate 11 to be processed by an objective lens 54. . The substrate 11 to be processed is placed on an XY stage 41, and the XY stage 41 is moved in the X-axis and Y-axis directions by drive motors 44 and 45 to adjust the laser processing position of the substrate 11 to be processed.

FIG. 3 is a block diagram showing the X-axis coordinate control of FIG. 1. The operation of an embodiment of the present invention will be explained using FIGS. 1 to 3.

When command coordinates is output to the driver 6.9 as the movement amount ΔX.

The movement amount ΔX is sent separately into a movement amount ΔX (coarse) for the XY stage section and a movement amount ΔX (fine) for the slit drive section 3. For example, if the positional accuracy of the XY stage 41 is about 5 μs, data on the movement amount ΔX (coarse) is sent as data in units of 2.5 sea bream.

On the other hand, if the accuracy required for the entire laser processing device (not shown) is about 0.3, the data on the movement amount ΔX (fine) is 0.3.
Data is sent in units of 1 instant.

The movable range of the slit of the slit opening 31 is the maximum opening width of the slit plus the moving distance that can cover the maximum positional error of the XY stage 41. For example, if the position error ΔE remains when the XY stage 41 is stopped, and if the reduction magnification of the slit opening is B, then the knife 37
．． 39 by a distance of EXB by the drive motors 32 and 34, the laser processing positions can be accurately aligned. At this time, the accuracy required for positioning the slit may be B times coarser, so there is an advantage that the mechanism of the slit driving section 3 is relatively easy to manufacture.

In addition, since the XY stage section 4 does not need to be ultra-precise,
A general XY stage section 4 with high speed and high acceleration can be used.
It has the advantage of being inexpensive and easy to maintain.

FIG. 4 is a block diagram showing a slit driving section according to an embodiment of the present invention. Other embodiments of the present invention have the same configuration as the one embodiment of the present invention except for this slit driving section. In the figure, plate spring mechanisms 62 to 6 that support the slit plate 61
5, a galvanometer 66.68 for moving the slit plate 61 in the X-axis and Y-axis directions, and an eccentric cam 67.69.
This slit driving section is constructed by the following. According to the position error data sent to the driver (galvanometer driver), eccentric cams 67, 69 attached to galvanometers 66, 68 rotate to translate the slit plate 61 supported by parallel leaf springs 62 to 65. Galvanometers 66 and 68 have hysteresis in rotation, but this hysteresis can be almost ignored because the slit position error tolerance is large and the slit movement distance is short and the amount of movement per rotation angle can be small. It becomes like this.

Furthermore, when forming an image using a slit shape, the slit opening diameter is often variable, but if a specific shape is sufficient, a fixed slit can be used as described above to reduce weight. Therefore, faster laser processing positioning is possible.

In this way, the laser processing position is roughly adjusted by moving the XY stage 41 in parallel on the plane perpendicular to the laser optical axis, and the slit opening 31 or the slit plate 61 is moved on the plane perpendicular to the laser optical axis. By finely adjusting the laser processing position by parallel movement, the XY stage section 4 can be manufactured at a relatively low cost and has high speed and high acceleration, although the accuracy is lowered.

At the same time, the slit opening 31 and the slit plate 61
Since the drive only needs to be performed with a position accuracy as coarse as the reduction magnification of the imaging system, the processing position can be corrected at high speed. Therefore, it is possible to realize an inexpensive laser processing apparatus that can perform high-speed processing while guaranteeing the accuracy of the laser processing position.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the laser processing position is coarsely adjusted by moving the XY stage in parallel on a plane perpendicular to the laser beam, and the slit opening is moved on the plane perpendicular to the laser beam. By finely adjusting the laser processing position by moving parallel to the stage, high-speed laser processing can be performed while ensuring the accuracy of the laser processing position, and the XY stage can be manufactured at low cost. effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of an embodiment of the present invention, FIG. 3 is a block diagram showing the X-axis coordinate control of FIG. FIG. 4 is a configuration diagram of a slit driving section according to another embodiment of the present invention. Explanation of symbols of main parts 2... Controller 3... Slit driving section 4... XY stage section 31... Slit openings 32 to 35... ...Drive motors 36 to 39...Knifetsuji 41...XY stage 42.43...Laser length measuring device 44.45...Drive motor 61...Slit plate

Claims (1)

[Claims] A laser processing position control method for a laser processing apparatus having an XY stage on which a substrate to be processed is placed and a slit opening for focusing laser light on the substrate to be processed, The laser processing position is roughly adjusted by moving the slit opening in parallel on a plane perpendicular to the laser beam, and the laser processing position is adjusted by moving the slit opening in parallel on a plane perpendicular to the laser beam. A laser processing position control method characterized by fine adjustment.