JP2020196032A - Laser processing device and laser processing method - Google Patents

Abstract

To make it possible to improve processing quality in laser processing for a substrate with non-uniform thickness.SOLUTION: In a laser processing method which performs relative movement of a laser irradiation part, which irradiates a work-piece with laser via a condenser lens and can move in an optical axis direction of the condenser lens, and a table on which the work-piece is loaded, thereby performing processing at different positions on a surface of the work-piece, a height in the optical axis direction at at least one position in a section of the surface of the work-piece, which is logically divided into plural sections, is detected before processing the work-piece, and movement of the laser irradiation part in the optical axis direction is performed in a period of performing the relative movement to the section to be the new processing position on the basis of the detection result.SELECTED DRAWING: Figure 1

Description

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

In a laser processing device that uses a laser to perform drilling on a printed circuit board, etc.
The laser pulse emitted from the laser oscillator is deflected in a two-dimensional direction by a galvano scanner and irradiated to a printed circuit board placed on a table via a condenser lens (Fθ lens).
In the conventional laser processing apparatus, for example, as shown in Patent Document 1, the thickness of the printed circuit board 1 is regarded as uniform, and the surface of the printed circuit board is at a position calculated based on the measured height of the table. The position of the printed circuit board of the laser irradiation unit in the thickness direction, that is, the position in the optical axis direction of the condenser lens is adjusted based on the height.
However, the thickness of this printed circuit board is not uniform when viewed in detail. Therefore, at the processing position where the surface height is different from the standard, the distance from the laser irradiation part is not appropriate in relation to the focal length of the condenser lens, and there is a problem that the processing quality is deteriorated such as a bad hole shape. is there.

Japanese Patent No. 4272667

Therefore, an object of the present invention is to improve the processing quality in laser processing of a substrate having a non-uniform thickness.

Among the inventions disclosed in the present application, typical laser processing devices include a table on which a work piece is placed, a laser irradiation unit that irradiates the work piece with a laser via a condenser lens, and the laser irradiation unit. The first drive unit for moving the condenser lens in the optical axis direction, the movement control unit for controlling the movement operation by the first drive unit, and the relative of the table and the laser irradiation unit. In a laser processing apparatus having a second driving unit for moving, at least one position in each of the compartments on the surface of the workpiece logically divided into a plurality of compartments in the optical axis direction. When a sensor for detecting the height is provided and the movement control unit sequentially performs machining in each of the compartments with relative movement by the second drive unit, the movement control unit is relative to the compartment to be a new machining position. It is characterized in that the first driving unit is operated based on the detection result by the sensor during the period of movement.

Further, among the inventions disclosed in the present application, a typical laser processing method is a laser irradiation unit that irradiates a work piece with a laser via a condenser lens, and moves the condenser lens in the optical axis direction. The work piece is processed in a laser processing method in which processing is performed at different positions on the surface of the work piece by performing relative movement between the work piece and the table on which the work piece is placed. The height of at least one position in each of the compartments on the surface of the workpiece logically divided into a plurality of compartments is detected in the optical axis direction, and a new height is detected based on the detection result. It is characterized in that the laser irradiation unit is moved in the optical axis direction during the period during which the relative movement is performed to the section to be the processing position.

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

According to the present invention, it is possible to improve the processing quality in laser processing of a substrate having a non-uniform thickness.

It is a block diagram of the laser processing apparatus which becomes one Example of this invention. It is sectional drawing of the printed circuit board which becomes the work of laser processing. It is a top view of the printed circuit board which becomes the work of laser processing. It is a figure for demonstrating the inside of the section in FIG. It is a flowchart of the operation performed prior to the drilling process. It is a figure which shows the content of the Z-axis position storage part in FIG. It is a figure for demonstrating the processing process of a plurality of sections.

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 an embodiment of the present invention. Each component and connecting line mainly shows what is considered necessary for explaining the embodiment, and does not show all necessary for a laser processing apparatus.
In this laser processing apparatus, the processing table 11 on which the printed circuit board 1 is placed is coupled to the table driving unit 12, and by driving the processing table 11, the printed circuit board 1 and the laser irradiation unit 13 move relative to each other in the X and Y directions. Can be done. As a result, a laser pulse is irradiated from the laser irradiation unit 13 to a predetermined position on the printed circuit board 1 to perform drilling.

Inside the laser irradiation unit 13, a condenser lens 14, a galvano scanner 16 that scans a laser pulse emitted from a laser oscillator 15 in a two-dimensional direction and irradiates the printed substrate 1 through the condenser lens 14, and displacement. The sensor 17 is mounted.
The laser irradiation unit 13 is coupled to the irradiation unit driving unit 18 so that it can move in the Z-axis direction (the optical axis direction of the condenser lens 14, that is, the thickness direction of the printed circuit board 1.
FIG. 2 is a cross-sectional view of a printed circuit board 1 that serves as a work for laser machining. The displacement sensor 17 measures the height of the surface of the printed circuit board 1 at an arbitrary position when viewed from the Z-axis direction. With reference to H0, the displacement amount is −Ah at the surface position A and the displacement amount at the surface position B. Is detected as + Bh.
The difference in displacement within one compartment is assumed to be small, and conversely, the size of one compartment is set so that the difference within the compartment is small.

Reference numeral 19 denotes an overall control unit that controls the operation of the entire apparatus, which is realized by, for example, a program-controlled processing apparatus, and each component and connection line in the overall control unit includes logical ones. Further, a part of each component may be provided separately from the overall control unit 19. In addition, the components and the lines connecting the components are mainly those considered to be necessary for explaining the present embodiment, and have components and control functions other than those described here. What you are doing.

The overall control unit 19 includes a table drive control unit 20 that controls the positioning operation of the table drive unit 12, a galvano scanner control unit 21 that controls the positioning operation of the galvano scanner 16 according to given drilling position information, and a given Z-axis position. The apex of each of the irradiation unit drive control unit 22 that controls the positioning operation of the irradiation unit drive unit 17 in the Z-axis direction according to the information, the program storage unit 23 for storing the machining program, the compartments S1, S2, S3 ... A vertex storage unit 24 and a Z-axis correction storage unit 25 for storing the coordinates of P1 to P4 are provided, respectively.

FIG. 3 is a plan view of the printed circuit board 1. The surface of the printed circuit board 1 is logically divided into a plurality of equal-sized compartments S1, S2, S3 ... Divided in a grid pattern.
The size of one compartment is an integral multiple of one scanning area of the galvano scanner 16 and is considerably larger than that size. The processing of the printed circuit board 1 is performed in each of the compartments S1, S2, S3 ... In units of one scanning area of the galvano scanner 15.
FIG. 4 is a diagram for explaining the inside of the compartment Sn in FIG. P0 is the intersection of two diagonals in the compartment Sn, and P1-4 are the vertices of the quadrilateral 32 connecting the points located exactly in the middle of the two diagonals in the compartment Sn.

This laser machining apparatus operates as follows under the control of the overall control unit 19 prior to performing drilling. FIG. 5 is a flowchart of this operation.
First, the printed circuit board 1 is moved relative to the displacement sensor 17 via the processing table 11 based on the coordinates of the vertices P1 to 4 in each of the compartments S1, S2, S3 ... The displacement amount is detected by the displacement sensor 17 and stored in the Z-axis correction storage unit 25 (step 100). The contents of the Z-axis correction storage unit 25 are shown in FIG.
Next, the displacement amounts h at the four vertices P1 to 4 are read from the Z-axis correction storage unit 25 for each of the compartments S1, S2, S3 ..., And the average hm of these displacement amounts (hereinafter, the average displacement amount). H10, h20, h30 ... (referred to as) are obtained and stored in the Z-axis correction storage unit 25 (step 200).

In order to ensure the processing quality, it is necessary to set the laser irradiation unit 13 at an appropriate Z-axis position Z. Therefore, next, a correction value (hereinafter referred to as a Z-axis correction value) for driving to an appropriate Z-axis position Z is obtained for each of the sections S1, S2, S3 ... Based on the average displacement amount hm. The Z-axis correction storage unit 25 is stored (step 300).
For example, in FIG. 6, if the average displacement amount hm is hm1, hm2, and hm3, the Z-axis correction values are k1, k2, and k3, respectively.
Note that FIG. 6 is for explaining the mutual logical relationship between the data stored in the Z-axis correction storage unit 25, and various data do not necessarily have to be stored as shown in the figure. In short, it suffices that the Z-axis correction values K1, K2, K3 ... Of each section S1, S2, S3 ... Can be obtained by the above logical relationship.

In this laser machining apparatus, when drilling is performed on the printed circuit board 1 for which the Z-axis correction values K1, K2, K3 ... Of all the compartments S1, S2, S3 ... It operates as follows under the control of the control unit 19.
FIG. 7 is a diagram for explaining a processing process of a plurality of sections. As shown by the arrow in FIG. 3, the processing order is assumed to be performed in the order of sections S1, S2, and S3. In FIG. 7, the relative movements N1 and N2 are the time to drive the machining table 11 in order to align the scan area of the galvano scanner 15 with the first scan area of the next section after the machining of the previous section is completed. is there.

First, it is assumed that the processing of the section S1 is performed in a state where the Z-axis position is adjusted so that the laser irradiation unit 13 can ensure appropriate processing quality. According to the present invention, when the processing of the compartment S1 is completed, the Z-axis correction value k1 for the next compartment S2 is read out from the Z-axis correction storage unit 25 during the period during which the relative movement N1 is performed, and the irradiation unit drive control unit 22 Given to. The irradiation unit drive control unit 22 controls the positioning operation of the irradiation unit drive unit 18 based on the Z-axis correction value k1, and properly processes the Z-axis position of the laser irradiation unit 13 before starting the processing of the next section S2. Complete positioning to a position where quality can be ensured.
Further, during the period during which the relative movement N2 is performed, the positioning of the Z-axis position of the laser irradiation unit 13 to a position where appropriate processing quality can be ensured is completed before starting the processing of the next section S2 in the same manner.

According to the above embodiment, the Z-axis position of the laser irradiation unit 13 is positioned at a position where appropriate machining quality can be ensured based on the displacement amount of the section to which the drilling position of the printed substrate 1 belongs, and then the machining is performed. Regardless of the flatness of the processing table 11, the distance between the drilling position and the laser irradiation unit 13 is appropriate for the focal length of the condenser lens 15 in all the sections 31, and the processing quality can be ensured.

Further, in the above embodiment, the Z-axis direction position of the laser irradiation unit 13 is adjusted based on the average displacement amount at the four vertices P1 to 4 of the quadrilateral in each section 31, but other The adjustment may be made based on the average displacement amount at the plurality of positions or the displacement amount at the center P0 in each section 31.
In short, it is sufficient to determine the detection method of the size and the amount of displacement of each section so that appropriate processing quality can be ensured at any position in the section.
Further, although the cases where the sizes of the compartments S1, S2, S3 ... Are the same are described, they may be different. For example, the partition may be set so that the correction can be performed with one Z-axis correction value.

Although the present invention has been described above based on the examples, the present invention is not limited to the examples, and it goes without saying that various modifications can be made without departing from the gist thereof. Is included.

1: Printed circuit board, 11: Processing table, 12: Table drive unit,
13: Laser irradiation unit, 14: Condensing lens, 15: Laser oscillator,
16: Galvano scanner, 17: Displacement sensor, 18: Irradiation unit drive unit,
19: Overall control unit, 20: Table drive control unit, 21: Galvano scanner control unit,
22: Irradiation unit drive control unit, 23: Program storage unit, 24: Vertex storage unit,
25: Z-axis correction storage unit

This laser machining apparatus operates as follows under the control of the overall control unit 19 prior to performing drilling. FIG. 5 is a flowchart of this operation.
First, the printed circuit board 1 is moved relative to the displacement sensor 17 via the processing table 11 based on the coordinates of the vertices P1 to 4 in each of the compartments S1, S2, S3 ... The amount of displacement is detected by the displacement sensor 17 and stored in the Z-axis correction storage unit 25 (step 100). The contents of the Z-axis correction storage unit 25 are shown in FIG.
Next, the displacement amounts h at the four vertices P1 to 4 are read from the Z-axis correction storage unit 25 for each of the compartments S1, S2, S3 ..., And the average hm of these displacement amounts (hereinafter, the average displacement amount). (Called) is obtained and stored in the Z-axis correction storage unit 25 (step 200).

Claims (4)

A table on which a work piece is placed, a laser irradiation unit that irradiates the work piece with a laser via a condenser lens, and a third unit for moving the laser irradiation unit in the optical axis direction of the condenser lens. A plurality of laser processing devices having a drive unit 1, a movement control unit that controls a movement operation by the first drive unit, and a second drive unit that performs relative movement between the table and the laser irradiation unit. A sensor for detecting the height of at least one position in each of the surfaces of the workpiece logically divided into the compartments in the optical axis direction is provided, and the movement control unit is the first. When machining is sequentially performed in each of the sections with relative movement by the driving unit 2, the first method is based on the detection result by the sensor during the period of performing the relative movement to the section to be the new machining position. A laser processing device characterized by operating a drive unit. In the laser processing apparatus according to claim 2, the positions detected by the sensor are set at a plurality of locations in the compartment, and the movement control unit is driven by the first drive based on the average detection values at the plurality of locations. A laser processing device characterized by controlling the operation of a unit. A laser irradiation unit that irradiates a work piece with a laser via a condenser lens that can move the condensing lens in the optical axis direction and a table on which the work piece is placed move relative to each other. As a result, in the laser processing method in which processing is performed at different positions on the surface of the work piece, the surface of the work piece is logically divided into a plurality of sections before the work piece is machined. The laser irradiation unit during a period in which the height of at least one position in each of the compartments in the above-mentioned section is detected in the optical axis direction, and the relative movement to the section to be a new processing position is performed based on the detection result. A laser processing method characterized by moving in the direction of the optical axis. In the laser processing method according to claim 3, the positions for detecting the height in the optical axis direction are set at a plurality of locations in the compartment, and the laser irradiation unit is based on the average detection values at the plurality of locations. A laser processing method characterized by moving in the direction of the optical axis.

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