JP2020049531A - Laser processing device and laser processing method - Google Patents

Abstract

To suppress positional deviation in processing based on telecentric errors in laser processing.SOLUTION: A laser processing device, which is configured to process a work-piece by making a galvano-scanner scan laser pulse emitted from a laser oscillator on the work-piece through a light condensing lens, on the basis of position information, is provided with a sensor that detects a height viewed from a thickness direction of a surface of the work-piece for each position shown by the position information before processing the work-piece, where a scan position at the time when the galvano-scanner scans the laser pulse is a position determined by correcting the position information by a numerical value determined based on the detected value detected by the sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser processing apparatus and a laser processing method for performing drilling and the like using a laser on a printed circuit board.

In laser processing equipment that performs drilling and the like using a laser on a printed circuit board,
The laser pulse emitted from the laser oscillator is deflected in a two-dimensional direction by a galvano scanner, and irradiates a printed board placed on a table via a condenser lens (Fθ lens).
In this case, for example, as disclosed in Patent Document 1, it is assumed that the thickness of the printed circuit board is considered uniform, and that the surface of the printed circuit board is located at a position calculated based on the height of the measured table. The position of the laser irradiation system in the Z-axis direction (the thickness direction of the printed circuit board) is adjusted based on the height.

FIG. 4 is a sectional view of a printed circuit board serving as a work. In FIG. 4, reference numeral 1 denotes a printed circuit board, and 2 denotes a laser pulse applied to the printed circuit board 1 via a condenser lens (Fθ lens) provided in a laser irradiation system.
Although FIG. 4 shows an exaggerated illustration, the surface of the printed circuit board 1 has irregularities when viewed in detail. At a position different from the reference height, a telecentric error occurs due to the characteristics of the condenser lens.
For example, in the case of FIG. 4, if the apparatus is set so that the height H0 is used as a reference, the point B at a height lower than the reference is shifted to the left at a point B ′ shifted by Lb, and the point C at a height higher than the reference is used. A hole or the like is machined at a point C 'shifted to the right by Lc.

In recent years, as the density of printed circuit boards has been increasing more and more, a processing positional shift based on a telecentric error due to such surface irregularities cannot be ignored.
As a method of correcting a positional shift in laser processing, for example, as disclosed in Patent Document 2, a method is known in which processing is performed on a test substrate and correction is performed based on the measured positional shift.
However, this method does not correct a positional shift caused by unevenness on the surface of a printed circuit board itself as a work.

Patent No. 4272667 JP-A-10-301052

  Therefore, an object of the present invention is to suppress a processing position shift based on a telecentric error in laser processing.

  Among the inventions disclosed in the present application, a typical laser processing apparatus scans a workpiece through a condensing lens with a laser pulse emitted from a laser oscillator by a galvano scanner based on positional information, and scans the workpiece. In a laser processing apparatus configured to process a workpiece, a sensor is provided for detecting a height of the surface of the workpiece viewed from a thickness direction at each position indicated by the position information before processing the workpiece. The scanning position at which the galvano scanner scans the laser pulse is obtained by correcting the position information with a numerical value obtained based on a detection value detected by the sensor.

  In addition, among the inventions disclosed in the present application, a typical laser processing method is to scan a workpiece through a condenser lens with a laser pulse emitted from a laser oscillator by a galvano scanner based on position information. In the laser processing method for processing the workpiece, before processing the workpiece, by detecting the height of the surface of the workpiece as viewed from the thickness direction at each position indicated by the position information. The scanning position at which the galvano scanner scans the laser pulse is obtained by correcting the position information with a numerical value obtained based on a detection value detected by the sensor at the scanning position.

  The typical features of the invention disclosed in the present application are as described above, but features not described here are described in the embodiments for carrying out the invention described later. As shown in the range.

  ADVANTAGE OF THE INVENTION According to this invention, in laser processing, the position shift of the processing based on a telecentric error can be suppressed.

1 is a block diagram of a laser processing apparatus according to one embodiment of the present invention. It is a top view of the printed circuit board used as a work. FIG. 2 is a diagram showing contents of a displacement table in FIG. 1. It is sectional drawing of the printed circuit board used as a workpiece | work. FIG. 3 is a diagram for explaining the inside of one section on the surface of a printed circuit board serving as a work.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a laser processing apparatus according to one embodiment of the present invention. The components and the connection lines are shown as those which are considered to be necessary mainly for explaining the embodiment, and do not show all the components necessary for the laser processing apparatus.
In this laser processing apparatus, a predetermined position on the printed circuit board 1 is irradiated with a laser pulse from the laser irradiation system 13 by relatively moving the printed circuit board 1 placed on the processing table 12 and the laser irradiation system 13 to form a hole. Processing is performed.

A galvano scanner 15 that scans the printed circuit board 1 with a laser pulse emitted from a laser oscillator via a condenser lens 14 is provided inside the laser irradiation system 13. The laser irradiation system 13 is provided with a displacement sensor 16 for detecting irregularities on the surface of the printed circuit board 1. The displacement sensor 16 detects the height of the surface at an arbitrary position when viewed from the Z-axis direction (the thickness direction of the printed circuit board) of the printed circuit board 1 and detects the amount of displacement based on a specific height. Output.
For example, in the case of FIG. 4, the displacement sensor 16 detects the displacement amount at the point B ′ as −Bh and the displacement amount at the point C ′ as + Ch based on the height H0 at the point A in FIG.

Reference numeral 17 denotes an overall control unit for controlling the operation of the entire apparatus, which is realized by, for example, a processing apparatus under program control, and each of the components and connection lines therein includes logical ones. Further, some of the components may be provided separately from the overall control unit 17. Also, the components and the lines connecting the components are shown mainly for the purpose of explaining the present embodiment, and have components and control functions other than those described here. What you are doing.
The overall control unit 17 includes a galvano scanner control unit 18 for controlling the positioning operation of the galvano scanner 15 according to the given position information, a displacement table 19 for registering information as one entry for each drilling position, and a processing program for storing a machining program. A program storage unit 20 is provided.

This laser processing apparatus operates as follows under the control of the overall control unit 17 before performing the drilling processing.
FIG. 2 is a plan view of a printed circuit board serving as a work for laser processing. The position information of each drilling position 3 of the printed circuit board 1 is incorporated in a processing program stored in a program storage unit 20. The printed board 1 is moved relative to the laser irradiation system 13 based on the position information, the displacement sensor 16 is aligned with the upper surface position of each drilling position 3, and the displacement sensor 16 detects the displacement amount. Register with.

Next, after the displacement amounts of all the drilling positions 3 are registered in the displacement table 19 as described above, the displacement amounts at the respective positions are read out, and how much the positioning of the galvano scanner 15 is corrected for each displacement amount. A correction value indicating whether to do so is obtained by a predetermined formula, and registered in the displacement table 19.
Note that the calculation formula for calculating the correction value from the displacement amount may be a formula obtained by an experiment or the like.

3 shows the contents of the displacement table 19, where a1, a2, a3,... Represent position information indicating the drilling position 3, h1, h2, h3, etc. represent displacement amounts at the respective positions, k1, k2,. k3... are correction values at respective positions.
The displacement table 19 here is for explaining the logical relationship between data, and it is not necessary that various data be registered as shown in the figure. The point is that the correction values k1, k2, k3,... Of the drilling positions a1, a2, a3,.

  For example, in the case of FIG. 4, if the apparatus is set so that the height H0 is used as a reference, if the drilling position is the height H0, no correction is required, and the correction value is zero, and the correction amount at the point B ′ where the displacement is −Bh Is a value to be corrected to the right by Lb, and a correction value to the C ′ point having a displacement amount of + Ch is a value to be corrected to the left by Lc.

The laser processing apparatus operates as follows under the control of the overall control unit 17 when performing drilling on the printed circuit board 1 for which the correction values of all the drilling positions 3 have been obtained as described above.
That is, when a hole is drilled at one drilling position 3, the corresponding correction value is read from the displacement table 19 based on the hole position information given from the machining program, the position information is corrected, and the corrected value is given to the galvano scanner controller 18. The galvano scanner controller 18 controls the positioning operation of the galvano scanner 15 based on the corrected position information. The same operation is performed for the other drilling positions 3.

  According to the above embodiment, the processing position is corrected based on the displacement amount of the drilling position 3 of the printed circuit board 1 itself as a work, so that it is possible to prevent the processing position shift due to the telecentric error.

In the embodiment described above, the displacement sensor 16 detects the displacement amounts of all the drilling positions 3. When the irregularities on the surface of the printed circuit board 1 change gradually, for example, the following can be performed.
That is, the surface of the printed circuit board 1 is divided into a plurality of sections divided in a grid shape, and before performing the drilling process, the displacement amount at a specific position in each section is obtained, and the displacement amount and the correction value are stored in the displacement table 19. Register.

  The displacement amount at a specific position in each section is, for example, as shown in FIG. 5, a displacement amount at one central position P0 in each section 31 or on the diagonal line and at the center. The average value of the displacement amounts at the vertices P1 to P4 of the quadrilateral 32 or the average value of the displacement amounts at a plurality of appropriate locations in each section 31 is used.

When drilling is performed on the printed circuit board 1, the correction value of the section to which the drilling position 3 belongs is read from the displacement table 19 based on the hole position information, and the position information is corrected.
In this way, the number of entries to be registered in the displacement table 19 is only the number of sections, and the number of entries can be reduced as compared with the case where all the drilling positions are registered.
In the case of a method in which the surface of the printed board 1 is divided into a plurality of areas, and each time processing of one area is completed, the printed board 1 and the laser irradiation system 13 are relatively moved to shift to processing of an adjacent area. One area may coincide with the section.

In the above embodiment, a correction value is read from the displacement table 19 every time a hole is drilled at one drilling position 3.
However, in the first place, the position information incorporated in the machining program stored in the program storage unit 20 is corrected with the correction value, and the position information is already corrected at the stage where the position information is given to the galvano scanner control unit 18 from the machining program. It may be.

  As described above, the present invention has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the gist of the present invention. Various modifications are included.

1: printed circuit board, 2: laser pulse, 3: drilling position, 12: processing table,
13: laser irradiation system, 14: condenser lens, 15: galvano scanner,
16: displacement sensor, 17: overall control unit, 18: galvano scanner control unit,
19: displacement table, 20: program storage unit, 31: section

Claims (8)

  In a laser processing apparatus configured to scan a workpiece through a converging lens with a laser pulse emitted from a laser oscillator by a galvano scanner based on position information and process the workpiece, the workpiece is Before processing, a sensor is provided for detecting the height of the surface of the workpiece viewed from the thickness direction for each position indicated by the position information, and the scanning position when the galvano scanner scans a laser pulse is the sensor Wherein the position information is corrected by a numerical value obtained based on a detection value detected by the laser processing device.   In a laser processing apparatus configured to scan a workpiece through a converging lens with a laser pulse emitted from a laser oscillator by a galvano scanner based on position information and process the workpiece, the workpiece is A sensor for detecting a height of the surface of the workpiece as viewed in a thickness direction before processing at each specific position in each of the sections of the workpiece in a grid shape; A laser processing apparatus wherein the scanning position at the time of scanning the laser pulse is obtained by correcting the position information by a numerical value obtained based on a detection value detected by the sensor in a section to which the scanning position belongs.   3. The laser processing apparatus according to claim 2, wherein the specific position is a central portion in each of the sections.   3. The laser processing apparatus according to claim 2, wherein the specific position in the section is a plurality of points, and the position information is corrected by a numerical value obtained based on an average value at the plurality of points. apparatus.   In a laser processing method for processing a workpiece by scanning the workpiece with a laser pulse emitted from a laser oscillator by a galvano scanner based on position information via a condenser lens, the workpiece is Before processing, the height as viewed from the thickness direction of the surface of the workpiece is detected for each position indicated by the position information, and the scanning position when the galvano scanner scans the laser pulse is the scanning position. Wherein the position information is corrected by a numerical value obtained based on a detection value detected by the sensor.   In a laser processing method for processing a workpiece by scanning the workpiece with a laser pulse emitted from a laser oscillator by a galvano scanner based on position information via a condenser lens, the workpiece is Before processing, the height of the surface of the workpiece as viewed in the thickness direction is detected at each specific position in each of the sections of the surface of the workpiece in a grid shape, and the galvano scanner detects the laser pulse. A scanning position when scanning is performed by correcting the position information with a numerical value obtained based on a detection value detected by the sensor in a section to which the scanning position belongs.   7. The laser processing method according to claim 6, wherein the specific position is a central portion in each of the sections. 7. The laser processing method according to claim 6, wherein the specific position in the section is a plurality of positions, and the correction of the position information is performed by a numerical value obtained based on an average value at the plurality of positions. Method.

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