JPH1058178A - Laser beam machine using plurality of axes galvano-scanners - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve machining speed by dividing a laser beam into a plurality of numbers and simultaneously machining a plurality of works with a plurality of laser beams. SOLUTION: A laser beam from a laser beam oscillator 10 is divided into two in a cross sectional area by a 45 deg. reflecting mirror 11 and respectively guided to masks 13a, 13b. The laser beams pass through the hole specifying a via hole diameter with the masks 13a, 13b with throttling its beam diameter and one guided to X-Y scanners 14a, 14b. By oscillating the laser beams with the X-Y scanners 14a, 14b and focusing with machining lenses 15a, 15b, works 17a, 17b are irradiated with the laser beams. Work stages 16a, 16b move and position the works 17a, 17b on a plane. In using a reflecting mirror of a triangular pyramid shape having three reflecting faces or quadrangular pyramid shape having four reflecting faces, the laser beam is divided into three or four equal parts, and machining speed can further be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus suitable for forming minute via holes in a printed wiring board.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and more sophisticated, the density of mounted components mounted on a printed circuit board and the lead pitch have been reduced. In order to cope with such progress, it is required that the diameter of a via hole formed in a printed wiring board be 0.3 (mm) or less.

Conventionally, drilling of a printed wiring board is performed by machining with an NC drill or exposure (photo via method). However, in the NC drill, the diameter of the hole is limited to 0.2 (mm), and the drill is often broken. On the other hand, in the photo via method, 0.15 (m
m) is the limit, and the material cost is high.

[0004] As a means for solving the above-mentioned problems, a laser processing apparatus for performing drilling with a laser beam has recently been provided. In this laser processing apparatus, a pulsed laser beam is generated by a laser oscillator, and the number of pulses and the energy for one hole are adjusted to perform drilling to a desired depth. On the other hand, with respect to the diameter of the hole, a mask for defining the diameter is arranged in the light guide path of the laser light, and the laser light is narrowed down by this mask, so that the hole provided in the workpiece can be reduced.

[0005] In addition, since the laser processing does not damage the metal, there is an advantage that the conductor pattern can be processed without damage even in processing after laminating the insulating layer film or processing from the base film side.

[0006]

An excimer laser is used as a laser oscillator. However, due to the etching speed (depth per pulse), the processing speed is relatively slow and the operating cost is high. There is a problem. On the other hand, a TEA (Transversely) having a narrow pulse width, high peak power and high energy density can be obtained.
Excited Atmospheric Press
ure) CO ₂ lasers are receiving attention. This TEA
Since a laser processing apparatus using a CO ₂ laser has an etch speed one digit or more higher than that of an excimer laser, the number of laser irradiation pulses required for processing per hole can be reduced, and the processing speed can be increased.

However, the above TEA CO
The processing speed even when using the ₂ laser is limited,
There is a need for an improvement to reduce the processing cost per hole.

An object of the present invention is to provide a laser processing apparatus capable of greatly improving a processing speed.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a laser processing apparatus for performing processing by irradiating a workpiece with laser light from a laser oscillator. It is characterized in that a dividing means for dividing into a plurality of pieces is arranged so that a plurality of workpieces can be processed with a plurality of divided laser beams.

According to the present invention, there is also provided a laser processing apparatus for performing processing by irradiating a workpiece with laser light from a laser oscillator, wherein a laser light guide path is divided into a plurality of sections with respect to a sectional area of the laser light. A means is arranged so that a workpiece to be processed can be simultaneously processed with a plurality of divided laser beams.

The dividing means is realized by a two-part type reflecting mirror having two reflecting surfaces and intersecting these reflecting surfaces at an angle of 90 °.

[0012] Further, the dividing means has a half reflecting surface,
The other half may be realized by a two-division type reflection mirror in which the reflection mirror is a 50% reflection mirror of the transmission surface.

Further, the splitting means may be realized as a two-split type which is an edge type mirror having an angle of 45 ° with respect to the optical axis of the laser beam.

Further, each of the two divided laser beams is arranged at a line symmetrical position with respect to the dividing means, and is guided to a galvano scanner by a combination of a plurality of galvanometer mirrors. It is preferable that the laser beam irradiate the placed workpiece to be irradiated.

[0015]

According to the present invention, a laser beam emitted from a laser oscillator usually has a square cross section with one side of a dozen (mm), and is squeezed by a mask before being irradiated on a workpiece. We pay attention to the point. That is, only a part of the laser light generated by the laser oscillator is used for processing.

According to the present invention, a laser beam from a laser oscillator can be divided into a plurality of parts without lowering its peak power or energy density. On the other hand, by performing simultaneous machining, the machining speed is improved as a result.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the first embodiment shown in FIG. 1, the pulsed laser light generated by the laser oscillator 10 using the TEA CO ₂ laser is 45 °
The cross section is divided into two by the reflection mirror 11,
The light is guided to the masks 13a and 13b while changing the angle by 90 °. In the masks 13a and 13b, the beam diameter of the divided laser beam is narrowed by passing through a hole that defines the via hole diameter, and the X-Y scanners 14a and 14b are separated.
b. The XY scanners 14a and 14b are for oscillating the laser light, and the oscillated laser light acts as a focusing lens and passes through the work stage 16 through processing lenses 15a and 15b also called fθ lenses.
A work (for example, a printed wiring board) 17a, 17b placed on a, 16b is irradiated. Work stage 1
6a and 16b have a drive mechanism in the X-axis direction and a drive mechanism in the Y-axis direction, and can adjust the position by moving the works 17a and 17b on the XY plane.

In FIG. 2A, a 45 ° reflecting mirror 1 is used.
1 has two reflecting surfaces 11a and 11b that intersect at 90 °, and thereby makes the incident laser light 2
Can be equally divided. For example, as shown in FIG. 2B, when the cross section of the laser beam is a square of 12 × 12 (mm), it can be equally divided into two laser beams having a cross section of 6 × 12 (mm). it can. In the masks 13a and 13b, the divided laser light is narrowed down through a hole (usually a diameter of 1 to 2 mm) having a diameter determined according to the reduction ratio M and the diameter of the via hole. Since it is sufficiently smaller than the area, there is no inconvenience caused by splitting the laser beam.

By the same principle, if a triangular pyramid-shaped reflecting mirror having three reflecting surfaces and a quadrangular pyramid-shaped reflecting mirror having four reflecting surfaces are used, laser light can be divided into three equal parts and four equal parts. .

FIG. 3 shows another example of the laser beam splitting means, in which the laser beam is split into two by using a 50% reflection mirror 21. The 50% reflective mirror 21 is formed by applying a reflective material to one half to form a reflective mirror 21a and the other half to be a transparent portion 21b of a total transmission type, so that the laser light can be bisected in terms of the sectional area.

FIG. 4 shows still another example of the laser beam splitting means, in which the laser beam is split into two using an edge type mirror 31 having a reflecting surface 31a at an angle of 45 ° with respect to the optical axis. .

The present invention is characterized in that laser light can be split without lowering the energy density of laser light by using the above-mentioned reflection mirror.

In FIG. 5, the XY scanner 14a (1
4b) is a so-called galvano scanner formed by combining two galvanometer mirrors 14-1 and 14-2. That is, by independently rotating the two reflecting mirrors based on the driving principle of the galvanometer, it is possible to continuously irradiate the laser beam to a plurality of desired positions on the work 17 through the processing lens 15.

A preferred example of the mask will be described with reference to FIG. The mask 13 includes a disk-shaped mask plate 13-1 having holes (here, 16 holes) H1 to H16 having different diameters at equal angular intervals in the circumferential direction, and a mask plate 13-1.
-1 and slightly larger than each of the holes H1 to H of the mask plate 13-1.
16 has windows W1 to W8 in an area corresponding to
FIG. 6C shows a mask holder 13-2 for holding 3-1.
As shown in FIG. 7, the driving unit 13-3 includes a motor that rotationally drives the mask plate 13-1 and the mask holder 13-2 combined together.

The mask 13 is arranged so that the holes H1 to H16 pass through the optical path of the laser beam when the mask plate 13-1 rotates. In other words, the rotation axis of the mask plate 13-1 is parallel to the optical path of the laser light, and the holes H1 to H
The virtual circles connecting the centers of the sixteen are arranged in the optical path of the laser light. Although not shown, the mask 13 further finely adjusts the position of the combination of the mask plate 13-1 and the mask holder 13-2 or the entire mechanism in parallel with respect to the surface of the mask plate 13-1. A mask position biaxial fine adjustment mechanism is provided for finely adjusting the center position of the hole corresponding to the optical path of the laser light.

The material of the mask plate 13-1 is SUS
Since it is necessary to irregularly reflect the reflected light of the laser beam so as not to affect other optical components of the laser light guide system, the surface is subjected to processing such as shot blasting. The diameter of the hole of the mask plate 13-1 is excellent in processability with respect to a resin such as epoxy or PI used for a high-density multilayer printed wiring board, and the energy density (fluence) of the processed surface is about 10 J / cm ² . It is designed based on the principle of the mask projection method. In this example, reduction ratio (M value)
Is designed to be about 10. In this case, the mask plate 13-
When one hole H10 is selected, the diameter of the via hole becomes 0.1
(Mm). This reduction rate (M value) is
It can be set arbitrarily by changing the distance between -1 and the processed lens.

The diameter of the via hole currently used is 0.1
(Mm) is the mainstream, so the diameters of the holes H1 to H16 provided in the mask plate 13-1 are mainly 1 to 2 (mm) and values before and after them, that is, H1: 8, H2: 6, H
3: 4, H4: 3, H5: 2, H6: 1.8, H7:
1.6, H8: 1.4, H9: 1.2, H10: 1.
0, H11: 0.9, H12: 0.8, H13: 0.
7, H14: 0.6, H15: 0.5, H16: 0.4
(The unit is mm). These holes are arranged counterclockwise in order from the larger one.

The drive unit 13-3 drives the mask plate 13-1 to rotate under the control of a main control unit (not shown). That is, the main control unit selects a hole corresponding to the diameter of the via hole specified based on the drill data set by the operator, master data such as a CAD file, and so on, so that this hole is positioned in the optical path of the laser beam. The plate 13-1 is rotated. Generally, a hole diameter is specified by a T code in drill data. In this example, a desired hole diameter can be set by rotating the mask plate 13-1 based on the T code.

Returning to FIG. 1, XY scanners 14a and 1
4b is preferably arranged in a line-symmetric relationship with respect to the 45 ° reflecting mirror 11. This is because the laser beam has the property that the beam diameter increases as the beam divergence angle, that is, the optical path length increases. On the other hand, the above arrangement makes it easier to make the distance from the laser light emission port of the laser oscillator 10 to the processing surface of the workpieces 17a and 17b equal, and makes the energy density of the laser light on the processing surface the same. be able to.

In any case, in this embodiment, the laser beam from the laser oscillator 10 is divided into two without lowering the energy density and guided to two laser processing systems, and the two workpieces 17a and 17b are applied to the two workpieces 17a and 17b. By performing exactly the same drilling on the other hand, the processing speed can be doubled. Therefore, the processing cost per hole can be significantly reduced.

A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, one work 17 placed on a work stage 16 is
In this embodiment, holes are simultaneously drilled by the Y scanners 14a and 14b. The configuration of the laser processing apparatus is the same as that of FIG.
Although the a and b operate on both sides of the work 17, the XY scanners 14a and 14b can be arranged close to each other, and the XY scanners 14a and 14b perform the simultaneous processing on the area where the work 17 approaches. It goes without saying that you can do it.
Further, the processing patterns for processing the two workpieces 17 may be the same or may be processed using different processing patterns.

Although the present invention is most effective when used for a TEA CO ₂ laser, the existing CO ₂ laser,
The present invention is applicable to any processing apparatus such as a YAG laser and an excimer laser, and the form of the laser light may be either pulsed or continuous wave. The workpiece is particularly suitable for a printed wiring board or a flexible printed wiring board, but can also be applied to other resins and glass.

[0033]

According to the present invention, a laser beam from one laser oscillator can be divided into a plurality of laser beams without reduction in energy density and introduced into a plurality of processing systems.
The simultaneous processing can greatly increase the processing speed of the work, and as a result, the processing cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of a laser processing apparatus according to the present invention.

FIG. 2 is an enlarged view (FIG. 2A) for explaining the operation of the 45 ° reflecting mirror shown in FIG. 1 and a view (FIG. 2B) for explaining a cross-sectional shape of laser light.

FIG. 3 is a diagram for explaining an alternative example of the 45 ° reflecting mirror shown in FIG. 1;

FIG. 4 is a view for explaining still another alternative example of the 45 ° reflecting mirror shown in FIG. 1;

FIG. 5 is a diagram showing a schematic configuration of the XY scanner shown in FIG. 1;

FIG. 6 is a diagram showing a configuration of another example of the mask shown in FIG. 1;

FIG. 7 is a block diagram showing a schematic configuration of a laser processing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 11 45 ° reflection mirror 11a, 11b Reflection surface 15, 15a, 15b Worked lens 16, 16a, 16b Work stage 17, 17a, 17b Work 21 50% reflection mirror 31 Edge type mirror

Claims (10)

[Claims] In a laser processing apparatus for performing processing by irradiating a workpiece with laser light from a laser oscillator, a dividing means for dividing the laser light into a plurality of sections with respect to a cross-sectional area thereof is arranged in a light guide path of the laser light. A laser processing apparatus characterized in that a plurality of workpieces can be processed with a plurality of divided laser beams. 2. A laser processing apparatus according to claim 1, wherein said dividing means is of a two-part type having two reflecting surfaces and intersecting said reflecting surfaces at an angle of 90 °. 3. A laser processing apparatus according to claim 1, wherein said dividing means is a two-part type, wherein a half is a reflecting surface and the other half is a 50% reflecting mirror of a transmitting surface. 4. The laser processing apparatus according to claim 1, wherein said dividing means is a two-part type which is an edge type mirror having an angle of 45 ° with respect to the optical axis of the laser beam. 5. The laser beam divided into two parts,
Guided to a galvano scanner by a combination of a plurality of galvanometer mirrors arranged at a line symmetric position with respect to the dividing means, and these galvanometer scanners oscillate a laser beam to irradiate the workpiece to be placed on a stage independent of each other. 3. The apparatus according to claim 2, wherein
A laser processing apparatus according to any one of claims 1 to 4. 6. A laser processing apparatus for performing processing by irradiating a workpiece with a laser beam from a laser oscillator, wherein a dividing means for dividing the laser beam into a plurality of sections with respect to a cross-sectional area thereof is disposed in a light guide path of the laser beam. A laser processing apparatus characterized in that a workpiece can be simultaneously processed with a plurality of divided laser beams. 7. The laser processing apparatus according to claim 6, wherein said dividing means is of a two-part type having two reflecting surfaces and intersecting said reflecting surfaces at an angle of 90 °. 8. The laser processing apparatus according to claim 6, wherein said dividing means is a two-part type, wherein a half is a reflection surface and the other half is a 50% reflection mirror of a transmission surface. 9. The laser processing apparatus according to claim 6, wherein said dividing means is a two-part type which is an edge type mirror having an angle of 45 ° with respect to the optical axis of the laser beam. 10. The laser beam divided into two is arranged at a line symmetric position with respect to the dividing means, guided to a galvano scanner by a combination of a plurality of galvanometer mirrors, and placed on a stage by these galvanometer scanners. The laser processing apparatus according to any one of claims 7 to 9, wherein the laser beam is irradiated to irradiate the workpiece.