JP2022057509A - Laser processing device and laser processing method - Google Patents

Abstract

To improve the processing accuracy of a drilling process in a laser processing device performing a drilling process on a thin printed wiring board using a laser.SOLUTION: A drilling process on a printed wiring board includes: generating a route of a galvano scan area so as to pass through a circular orbit centering on the barycentric position of the above board to go around from the outer peripheral part of the printed wiring board toward the inner peripheral part thereof; measuring the telescopic motion amount of the board in the in-plane direction of the printed wiring board using the alignment mark provided on the printed wiring board as a reference every circuit of the route of a galvano scan area; and correcting a processing position in response to the telescopic motion amount of the printed wiring board in the in-plane direction to process.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method of correcting a machining position of laser machining in which a workpiece such as a printed circuit board is drilled by using a laser pulse.

In the circuit formation of the printed wiring board, a through hole is formed in a thin double-sided plate in which thin copper foils are arranged on both sides of the thin insulating layer. When making a through hole by laser processing, laser light is irradiated from both the front side and the back side of the printed wiring board, and the formed processed holes are connected to form a through hole. At this time, since it is necessary to match the positions of the holes on the front side and the holes on the back side, it is important to correct the position of the drilling process.

Further, since the printed wiring board is distorted such as expansion and contraction due to the influence of temperature change and the like, the processing position is corrected before the processing in the laser hole drilling processing of the printed wiring board.
For example, in the technique disclosed in Patent Document 1, when distortion such as expansion and contraction of the printed wiring board occurs, printing is performed from the deviation of the position of the alignment mark with reference to the alignment marks provided at the four corners of the printed wiring board. After calculating the amount of deformation of the wiring board and adding the correction value according to the amount of deformation to the positioning position of the XY table and the processing position coordinates of the processing program, laser drilling is performed on the entire surface of the printed circuit board.

Laser drilling of printed wiring boards creates a path of movement for the galvano scan area. For example, in the technique disclosed in Patent Document 2, in order to shorten the processing time, a spiral path is generated as a moving path of the galvanoscan area so that the machining path is the shortest.

Japanese Unexamined Patent Publication No. 2013-125915 Japanese Unexamined Patent Publication No. 2011-140057

In the conventional technique, as shown by an arrow in FIG. 4, processing is performed along the path of the spiral scan area from the path start point D45 of the outer peripheral portion of the printed wiring board 9. However, since the expansion and contraction of the printed wiring board during the drilling process has a larger outer peripheral portion than the central portion of the printed circuit board, the scan area A25, the scan area B26, and the scan area change the direction of the path by the conventional spiral path. In C27 and the scan area D28, there is a problem that a portion having a larger expansion / contraction amount is passed in the middle of the path, and the deviation of the hole drilling position becomes large. As described above, in the prior art, consideration has not been given to generating a machining path for reducing the deviation of the hole drilling position.

Further, in the prior art, since the hole drilling position is not corrected during the laser drilling process of the printed wiring board, there is a problem that the hole drilling position shifts due to the expansion and contraction of the printed wiring board generated during the laser hole drilling process.

In order to solve the above problems, in the present invention, a path of a scan area along a region having the same amount of expansion and contraction centered on the center of gravity of the printed wiring board is generated, and the path of the generated scan area is circulated. Furthermore, the machining position is corrected with reference to the alignment mark for each round of the generated scan area path.

The typical features of the invention disclosed in the present application are as described above, but the features not described here are applied to the examples described below, and are also included in the claims. As shown.

According to the present invention, in the front and back processing in which a printed wiring board having a thin insulating layer and a thin surface copper foil is irradiated with a laser from the front and back to form a through hole, the processing position is corrected for each orbiting scan area. It is possible to reduce the deviation of the machined position and machine a hole with high accuracy of the machined hole position.

It is a schematic diagram which shows the whole of the example of the laser processing apparatus to which this invention is applied. It is a figure which shows an example of the route of the galvanoscan area to which this invention is applied. It is sectional drawing of an example of the printed circuit board to which this invention was applied. It is a figure which shows the path of the galvanoscan area of the conventional laser processing apparatus.

FIG. 1 is a schematic diagram showing an outline of the laser processing apparatus of the present invention. The laser processing device can move at the same time as the laser oscillator 1, the control device 3, the first and second reflection mirrors 4, 5, the first and second galvano scanners 6, 7, the f theta lens 8, and the f theta lens 8. It is basically composed of an alignment mark recognition camera system 11 and an XY table 15 fixed to a plate (not shown).

Alignment marks 10 that serve as a reference for drilling positions are formed at the four corners of the printed wiring board 9. 12 is a galvanoscan area processed by the positioning operation of the galvano scanners 6 and 7, 13 is a galvanoscan area processed next to 12, and 15 is a mechanism in a feed system (not shown) in the front-rear direction of 17 when viewed from the front of the machine. XY table supported by.

The laser beam 2 oscillated from the laser transmitter 1 is reflected by the mirror 4 and the mirror 5, is incident on the galvano scanner 6 and the galvano scanner 7, and is irradiated on the surface of the printed wiring board 9 via the f-theta lens 8. Ru.

The camera system 11 for recognizing the alignment mark recognizes the alignment marks 10 arranged at the four corners of the printed wiring board 9 which is the workpiece, measures the position of the alignment mark 10 with respect to the laser processing machine of the printed wiring board 9, and processes the processing position. After performing the correction processing of, a movement command is given to the galvano scanners 6 and 7 and the XY table 15, and the machining position is positioned.

FIG. 2 is a schematic diagram showing an example of a path of a galvanoscan area generated by the laser processing apparatus of the present invention. On the printed wiring board 9 of FIG. 2, alignment marks 10 that serve as a reference for drilling positions are arranged at four corners of the printed circuit board (P1, P2, P3, P4).

As an example of a region in which the amount of expansion and contraction of the printed wiring board 9 is the same centering on the center of gravity 20 of the printed wiring board, a concentric region A21, a region B22, a region C23, and a region D24 are shown.

Next, the procedure of path generation of the galvanoscan area by the laser processing apparatus of the present invention will be described with reference to FIG. First, the scan area A25, the scan area B26, the scan area C27, and the scan area D28 that pass through the outermost region A21 are used as routes. Next, the scan area is moved to the path start point A29 of the route of the scan area passing through the region B22 on the inner circumference of the region A21, the scan area is moved toward the right in FIG. 2, and the scan area is the outer peripheral region. After moving to the upper scan area before being included in A21, then moving to the right scan area before the scan area is included in the inner peripheral area C23, then moving to the upper scan area again, and so on. Then, the circuit path of the scan area passing through the area A22 is determined.

After that, in the same manner, the route of the scan area passing through the area C23 is generated from the route starting point B30, and the route of the scanning area passing through the area D24 is generated from the route starting point C31, and the route is generated in the central area of the printed wiring board 20. Generate an orbital route to reach.

Next, as described above, drilling is performed along the path of the galvanoscan area, which is generated along the same region with the amount of expansion and contraction centered on the center of gravity of the printed wiring board, orbits in the plane of the printed wiring board. Explain the result of the work. FIG. 3 is a diagram showing a processing result by the laser processing apparatus of the present invention. A front side hole 41 was formed on the front side of the printed wiring board 9 and a back side hole 42 was formed on the back side with reference to the machined hole center position 40 of the printed wiring board. The front side hole 41 and the back side hole 42 are formed with holes penetrating the printed wiring board with the center position 40 of the machined hole as the coaxial center.

Next, another embodiment of the present invention will be described with reference to FIG. First, the processing positions with respect to the scan area A25, the scan area B26, the scan area C27, and the scan area D28 passing through the area A21 are corrected with reference to the alignment mark 10, and then the scan area A25, the scan area B26, and the scan area C27, The scan area D28 is processed. Next, the processing position in the scan area of the circuit path from the route start point A29 passing through the region B22 is corrected with reference to the alignment mark 10, and then processing is performed along the circuit path from the route start point A29. Hereinafter, in the same manner, the circuit is processed up to the central portion of the printed wiring board 9 along the circuit path from the path start point B30 passing through the region C23 and the circuit path from the path start point C31 passing through the region D24.

Also in the processing results described above, as shown in FIG. 3, the front side hole 41 and the back side hole 42 are formed with holes penetrating the printed wiring board with the processing hole center position 40 as the coaxial center.

In this embodiment, the locus is set to 4 laps as an example, but an arbitrary number of laps may be set according to the dimensions of the printed wiring board and the dimensions of the scan area.

In addition, in the processing of the first printed wiring board, the amount of expansion and contraction is measured for each round of the movement path of the galvano scan area and reflected in the correction amount, but the processing of the second and subsequent printed wiring boards is performed. Then, by storing and using the correction coefficient obtained for each orbital path of the galvanoscan area, which is measured and grasped by the first sheet, it is not necessary to newly measure the alignment correction value for each orbit.

1: Laser oscillator 2: Laser beam 3: Control device 4: First corner mirror 5: Second corner mirror 6: First galvano scanner 7: Second galvano scanner 8: f Theta lens 9: Printed wiring board 10: Alignment mark 11: Camera system for alignment mark recognition 12: Galvano scan area 13: Next galvano scan area 15: XY table 16: Y direction 17: X direction 20: Printed wiring board center of gravity 21: Area A
22: Area B
23: Area C
24: Area D
25: Scan area A
26: Scan area B
27: Scan area C
28: Scan area D
29: Route start point A
30: Route start point B
31: Route start point C
40: Machined hole center position 41: Front side hole 42: Back side hole 45: Path start point D

Claims (4)

A laser processing device characterized in that it passes through a circular orbit centered on the position of the center of gravity of the printed wiring board and generates a path of a galvano scan area so as to orbit from the outer peripheral portion to the inner peripheral portion of the printed wiring board. .. In the laser processing apparatus according to claim 1, each time the scan area of the galvano makes one round of the path of the scan area, the alignment mark provided on the printed wiring board is used as a reference in the in-plane direction of the printed wiring board. A laser processing apparatus characterized in that the amount of expansion and contraction is measured and the processing position is corrected according to the amount of expansion and contraction in the in-plane direction of the printed wiring board. A laser processing method characterized in that a path of a galvano scan area is generated so as to pass through a circular orbit centered on the position of the center of gravity of the printed wiring board and orbit from the outer peripheral portion to the inner peripheral portion of the printed wiring board. .. In the laser processing method according to claim 3, every time the scan area of the galvano makes one round of the path of the scan area, the alignment mark provided on the printed wiring board is used as a reference in the in-plane direction of the printed wiring board. A laser processing method characterized by measuring the amount of expansion and contraction and correcting the processing position according to the amount of expansion and contraction in the in-plane direction of the printed wiring board.

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