JPH0534116B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a laser processing position control device, and particularly to a laser processing position control device that places a substrate to be processed on an XY stage and directs a laser beam irradiated through a slit opening onto the substrate to be processed using a lens. The present invention relates to a laser processing position control device for a laser processing apparatus that performs fine processing by forming an image.

Conventional technology 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 is The XY stage, which performs positioning by placing and moving an object, must be extremely precise with respect to the laser processing spot.

Ultra precision XY used for such applications
Stages that have been put into practical use include those that have a fine-movement XY stage for precise positioning on top of a less precise coarse-movement XY stage, and those that achieve ultra-precise positioning using only a single XY stage.

In such conventional laser processing equipment, in the type in which a fine movement XY stage is installed on a coarse movement XY stage, the XY stage mechanism is complicated due to the two-stage structure, and a control device for the fine movement XY stage is required. The disadvantage is that it is costly because it is necessary. In addition, a device that achieves ultra-precise positioning with only one XY stage
The disadvantage is that the stage mechanism is difficult to manufacture and expensive.

Ultra-precision laser processing using these conventional XY stages currently has an upper limit of processing several points per second.

Purpose of the Invention The present invention was made in order to eliminate the drawbacks of the conventional ones as described above, and 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 purpose of the present invention is to provide a laser processing position control device that can perform the following tasks.

Configuration of the Invention A laser processing position control device according to the present invention is a laser processing device for laser processing having an XY stage on which a substrate to be processed is placed, and a slit opening for focusing laser light onto the substrate to be processed. The position control device includes means for roughly adjusting the laser processing position by moving the XY stage in parallel on a plane perpendicular to the laser beam, and means for roughly adjusting the laser processing position by moving the XY stage in parallel on a plane perpendicular to the laser beam; and means for finely adjusting the laser processing position by moving the slit opening in parallel on a perpendicular plane while keeping the size of the slit opening constant.

Embodiment 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 includes a central processing unit (hereinafter referred to as CPU) 1, a controller 2 that adjusts the laser processing position, and a slit drive unit 3.
and an XY stage section 4 on which the substrate to be processed 11 is placed.
and drivers 5 to 10.

The controller 2 is composed of comparators 21 and 22 and counters 23 and 24, and receives the current coordinates inputted by the X-axis position pulse 46 and Y-axis position pulse 47 from the XY stage section 4 from the CPU 1 via the bus line 25. The input command coordinates are compared with the comparators 21 and 22, and the comparators 21 and 22 send movement amounts to each of the drivers 5 to 10 according to the comparison results.

The slit drive unit 3 has knife edges 36 to 39.
Adjust the slit width with
Slit opening 31 that moves in the axial and Y-axis directions
and drive motors 32-35 for moving knife edges 36-39, respectively. The drive motors 32 to 35 are DC motors equipped with encoders, which are driven by drivers 5 to 8, respectively, to move the knife edges 36 to 39, respectively, so as to keep the slit dimensions constant and 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 to be processed 11 is placed, and an XY stage 41
Laser length measuring devices 42, 43 attached to
It is composed of drive motors 44 and 45 for moving the stage 41 in the X-axis and Y-axis directions. The drive motors 44 and 45 are driven by drivers 9 and 10, respectively. 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, and a slit opening 31 is moved by a slit driving unit 3.
Through the objective lens 54, the substrate 11 to be processed is
imaged on top. 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 the command coordinate XDES is given from the outside via the CPU 1 on the bus line 25, the controller 2
Then, the difference (XDES-
XPOS) is output to the drivers 6 and 9 as the movement amount ΔX. The movement amount ΔX is the movement amount ΔX (coarse) for the XY stage section 4 and the movement amount ΔX for the slit drive section 3.
(slight) and send separately. For example, if the positional accuracy of the XY stage 41 is about 5 μm, the movement amount ΔX
(Coarse) data is sent in units of 2.5 μm.

On the other hand, if the accuracy required for the entire laser processing apparatus (not shown) is about 0.3 μm, data on the movement amount ΔX (fine) is sent in units of 0.1 μm.

The movable range of the slit in the slit opening 34 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 a position error ΔE remains when the XY stage 41 is stopped, and if the reduction magnification of the slit opening is B, the laser The machining position can be adjusted accurately. 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 drive section 3 is relatively easy to manufacture.

Furthermore, 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, which has the advantage of being inexpensive and easy to maintain.

FIG. 4 is a block diagram showing a slit driving section according to another embodiment of the present invention. Other embodiments of the present invention have the same structure as the one embodiment of the present invention except for this slit drive section. In the figure, the slit plate 61
The leaf spring mechanisms 62 to 65 that support the slit plate 6
This slit drive section is composed of galvanometers 66, 68 for moving the slit 1 in the X-axis and Y-axis directions, and eccentric cams 67, 69. According to the position error data sent to the driver (galvanometer driver), eccentric cams 67 and 69 attached to galvanometers 66 and 68 rotate, and the slit plate 61 supported by parallel plate springs 62 to 65 rotates.
Move in parallel. The 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.

Also, when it comes to the shape of the slit, the aperture diameter of the slit is often variable when forming an image, but if a specific shape is acceptable, weight reduction can be achieved by using a fixed slit as described above. , faster laser processing positioning becomes 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 in parallel 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. Similarly, since the slit opening 31 and the slit plate 61 need only be driven with a positional precision as coarse as the reduction magnification of the imaging system, the machining 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.

Effects of the Invention As explained above, according to the present invention, the laser processing position is coarsely adjusted by moving the XY stage in parallel on the 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. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a schematic configuration diagram of one embodiment of the present invention, FIG. 3 is a block diagram showing the X-axis coordinate control of FIG. 1, and FIG. 4 is a slit drive section of another embodiment of the present invention. FIG. Explanation of symbols of main parts, 2... Controller,
3...Slit drive unit, 4...XY stage unit,
31...Slit opening, 32-35...Drive motor, 36-39...Knife edge, 41...
XY stage, 42, 43...Laser length measuring device, 4
4, 45... Drive motor, 61... Slit plate, 62-65... Leaf spring mechanism, 66, 68...
Galvanometer, 67, 69...eccentric cam.

Claims (1)

[Claims] 1. A laser processing position control device 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, wherein the XY stage is means for roughly adjusting the laser processing position by moving the slit opening in parallel on a plane perpendicular to the laser beam; 1. A laser processing position control device comprising means for finely adjusting a laser processing position by moving the laser processing position in parallel while keeping the position constant.