JPH04280698A - Conductive pattern cutting method and device of printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cutting conductive patterns on printed wiring boards using a continuous wave YAG laser.

[0002] When modifying a printed wiring board unit (electronic circuit package) in which various electronic components are mounted on a printed wiring board, or when repairing a printed wiring board unit, a continuous wave YAG laser is usually used to remove copper. It is necessary to cut the pattern.

0003

[Prior Art] Currently, when it is necessary to cut a copper pattern when modifying or repairing a printed wiring board unit, continuous wave YAG with constant power per unit area is used.
The copper pattern is cut using a laser by scanning the laser beam in a direction perpendicular to the copper pattern.

0004

However, as shown in FIG. 4, the cross section of the copper pattern 4 formed on the glass epoxy resin substrate 2 does not always have a uniform thickness, but has a non-uniform thickness. ing. Therefore, when the YAG laser beam 8 with a constant power per unit area is scanned at a constant speed in the direction of the arrow to cut the copper pattern 6, the thickness of the copper pattern 4 is not uniform, so there is no uncut portion of the copper pattern 4. The surface of the glass epoxy resin substrate 2 was irradiated with the laser beam 8, causing damage to the resin portion. Figure 4
, the copper pattern 4 is covered with a resist 6.

[0005] The present invention has been made in view of the above points, and its object is to improve the conductivity of a printed wiring board so that a conductive pattern can be reliably cut without damaging the board. An object of the present invention is to provide a pattern cutting method and apparatus.

[0006]

[Means for Solving the Problems] A method of cutting a conductive pattern 4 of a printed wiring board using a laser with constant power per unit area, first, as shown in FIG. Measure the thickness of pattern 4 using a non-contact film thickness meter 10
etc. to measure along the cut cross section. Then, as shown in FIG. 2, the conductive pattern 4 is cut by changing the laser scanning speed so that the laser scan speed is slow in thick places P1 and fast in thin places P2 according to this measurement value. do.

According to another aspect of the present invention, a laser oscillation means for oscillating a laser with constant power per unit area, an X-Y table movable in the X and Y directions on which a printed wiring board is placed; a table driving means for driving the X-Y table, a non-contact film thickness meter for measuring the thickness of the conductive pattern to be cut along the cutting cross section, and the table driving means according to the output of the film thickness meter. Provided is a conductive pattern cutting apparatus for a printed wiring board, characterized in that it comprises a control means for controlling the driving speed of the printed wiring board.

[0008]

[Operation] Since the scanning speed of the laser is changed according to the thickness of the conductive pattern, the apparent power (integrated power) changes. This makes it possible to reliably cut a conductive pattern with non-uniform thickness, and also prevents damage to the resin since the surface of the resin substrate is not irradiated with the laser.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on embodiments shown in the drawings. FIG. 3 shows a block diagram of a copper pattern cutting apparatus for a printed wiring board according to an embodiment of the present invention. Reference numeral 12 denotes an X-Y table on which a printed wiring board 14 is mounted, and is movable in the X direction and the Y direction by table driving means 16.

Reference numeral 18 is, for example, a non-contact film thickness meter manufactured by Union Engineering Co., Ltd., and the measuring head 20 of the film thickness meter 18 measures the thickness of the copper pattern to be cut on the printed wiring board 14 along the cutting cross section. do. Film thickness meter 18 outputs measured thickness information to controller 24 .

When the copper pattern on the printed wiring board 14 is cut by the laser beam oscillated from the YAG laser oscillation source 22, the controller 24 moves the table driving means 1 according to the film thickness information of the copper pattern to be cut.
Controls the drive speed of 6. That is, the driving speed of the table driving means 16 is increased where the copper pattern is thin, and the driving speed is decreased where the copper pattern is thick to increase the integrated power of the laser beam, thereby cutting the copper pattern.

Note that the controller 24 also performs on/off control of the YAG laser oscillation source 22. The YAG laser oscillation source 22 continuously outputs a laser beam with constant power per unit area.

[0013]

Effects of the Invention As described in detail above, the present invention measures the thickness of the conductive pattern along the cut section in advance and changes the scanning speed of the laser beam according to this thickness. The integrated power of the laser beam can be changed depending on the thickness of the substrate, and the conductive pattern can be reliably cut without damaging the substrate.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing how the film thickness of a copper pattern is measured.

FIG. 2 is a graph showing changes in scan speed.

FIG. 3 is a block diagram of an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a copper pattern.

[Explanation of symbols]

2 Glass epoxy resin substrate 4 Copper pattern 6 Resist 8 Laser beam 10, 18 Non-contact film thickness meter 12 X-Y table 14 Printed wiring board 16 Table driving means 22 YAG laser oscillation source 24 Controller

Claims (2)

[Claims] 1. A method for cutting a conductive pattern on a printed wiring board using a laser with constant power per unit area, the method comprising: cutting a conductive pattern (4) to be cut by cutting the conductive pattern along the cutting cross section; The conductivity of a printed wiring board is characterized in that the conductive pattern (4) is cut by measuring the conductive pattern (4) and changing the scanning speed of the laser so that it is slow in thick places and fast in thin places according to the measured value. How to cut sexual patterns. 2. A laser oscillation means (22) that oscillates a laser with constant power per unit area, and an X-Y movable in the X and Y directions on which a printed wiring board (14) is placed.
A table (12), a table driving means (16) for driving the X-Y table (12), and a non-contact film thickness meter (18) for measuring the thickness of the conductive pattern to be cut along the cutting cross section. and a control means for controlling the driving speed of the table driving means (16) according to the output of the film thickness meter (18).
24) A conductive pattern cutting device for a printed wiring board, characterized by comprising: