JP2001252784A - Laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device which realizes uniform machined diameters and shapes of holes and prevents clogging of chips in a boring work of a substrate for electronic circuit by the laser beam. SOLUTION: A predetermined gap is formed between a substrate for electronic circuit and a work-receiving base by air ejected from the work-receiving base, and uniform hole diameters and shapes of holes are obtained and the clogging with residual machined chips is suppressed by placing the work- receiving base and the substrate for electronic circuit in a state of non-contact with each other.

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 technique for uniformly processing a hole and a hole shape of an electronic circuit board without being affected by a workpiece.

[0002]

2. Description of the Related Art The performance of an electronic circuit board on which a semiconductor integrated circuit is mounted has been improved and the degree of integration has been increased, and the circuit wiring formed on the substrate has been miniaturized and densified. Therefore, a processing technique for performing high-speed and high-precision drilling on an electronic circuit board is required. As a method of drilling such an electronic circuit board, for example, a method of drilling a ceramic green sheet is currently in practical use by a YAG laser.

In this conventional laser processing apparatus, Japanese Patent Application Laid-Open
As shown in -6067, the mounting table has a concave portion, a plurality of rod members are arranged with a predetermined gap in the opening of the concave portion, and the workpiece on the sheet is line-contacted with the rod member. This is a method of receiving a sheet by placing it.

As shown in Japanese Patent Application Laid-Open No. 6-198482, the tip of the work supporting pin is configured to be detachable so that it can be replaced, and it is formed of a material having high heat resistance and abrasion resistance, and has a high durability. This is a method for improving and reducing running costs.

[0005]

The problem to be solved by the present invention will be described with reference to FIG.

In the conventional laser processing apparatus, in processing an electronic circuit board, for example, in forming a ceramic green sheet, as shown in FIG. Or, if it is located on the work receiving pin, it comes into contact with the glass tube or the work receiving pin, causing an explosion 4 of the prepared hole, causing the hole diameter and hole shape to become non-uniform, Since it exists below the hole, the processing residue is difficult to be removed from the processing hole, and there is a possibility that the clogging 5 occurs and the drilling becomes defective. Furthermore, when processing the electronic circuit board, the laser beam is focused and has a sufficient energy density to process the work receiver, so these work receivers may be damaged by the laser light, Labor and cost.

[0007]

In order to solve the above-mentioned problems, a work receiver according to the present invention forms a predetermined gap between an electronic circuit board and a work receiver by air blown out of the work receiver. By making the electronic circuit board non-contact, a uniform hole diameter and hole shape can be obtained without being affected by the work receiver, and due to the processing residue generated due to the contact part with the work receiver It can prevent clogging. Also, since the glass tube and work receiving pins are not used during processing, the holding jig is not damaged by laser irradiation and can be used without replacement, so the running cost of the work receiver can be reduced compared to the conventional method. It is possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 2 is a laser processing apparatus according to the present invention, FIG.
4 is a schematic view of a work receiver in the laser processing apparatus of the present invention, and FIG. 5 is a flowchart for explaining a processing procedure.

FIG. 2 is a schematic view of a laser processing apparatus according to the present invention. The processing apparatus includes an oscillator 6 for processing an electronic circuit board, a mask 8 for shaping a beam, a two-axis scan mirror 9 for scanning a beam, an fθ lens 10 for condensing a laser beam, and a sheet. Work holder 1
It is composed of an XY stage 11 provided with two. If necessary, an expander 7 for changing the beam spot diameter is attached to the optical system. The laser oscillator 6, the two-axis scan mirror 9, and the XY stage 11 are controlled by the control device 14.
During processing, the electronic circuit board 13 to be processed is moved to the XY stage
It is structured to be placed on a work receiver 12 attached to 11.

FIG. 3 is a schematic view of a work receiver. The work receiver 15 has an air outlet 16 for forming a gap between the electronic circuit board, a gap sensor 17 for measuring a distance between the electronic circuit board and the work receiver, and a positioning for setting the electronic circuit board at a predetermined position. It is composed of pins 18 and fixed pins 19. The work receiver 15 has a flat surface so that the gap between the electronic circuit board and the work receiver is uniformly formed during processing. The gap sensor has a function capable of measuring with an accuracy of ± 50 μm or less using a photoelectric sensor, a capacitance sensor, or the like regardless of the substrate material and the surface state.

An electronic circuit board, which is a workpiece, is fixed to a predetermined position by being placed on a work receiver 15 and pressed against positioning pins 18 with fixing pins 19. When fixing the electronic circuit board to the work receiver, it is set at a predetermined position using a fixing jig 21 as necessary.

An air outlet 16 for forming a gap 22 between the work receiver 15 and the electronic circuit board 20 and a gap sensor 17 for measuring the gap 22 between the work receiver 15 and the electronic circuit board 20 are provided on the upper surface of the work receiver 15. It is provided. In the air outlet 16, a plurality of circular holes 16 are formed at intervals of, for example, 5 mm in order to maintain the gap 22 with the electronic circuit board 20, and a sensor for measuring the gap beside the hole 16 is formed. 17 are located.

Air has a certain gap with the electronic circuit board 20.
Air necessary for forming the nozzle 22, that is, for maintaining a constant processing focus position, is supplied from the air valve 23 to the outlet 16 through the pipe 22. At this time, the gap is measured together with the air supply, and the measurement data is transmitted to the control device 26 through the signal line 25. From the transmitted measurement data, the air supply amount required to form a certain gap is analyzed by the control device 26, and the air valve 23 is controlled, and the
16 is supplied with an appropriate air flow rate.

Referring now to FIG. 5, a procedure for drilling an electronic circuit board according to the present invention will be described. Here, the processing procedure will be described with reference to FIG.

Since the ceramic green sheet is fragile, it is attached to a stainless steel sheet frame as the fixing jig 21 and set in a work receiver. The set of sheets is
This sheet frame is placed on the work receiver 15, and the sheet frame is aligned with the positioning pins 18 for temporarily determining the position of the sheet frame.

After the ceramic green sheet adhered to the sheet frame is placed on the work receiver 15, the sheet is set at a predetermined position by the fixing pin 19. After the control device 26 recognizes that the sheet frame 20 is fixed, the air valve 23 is opened by the control device 26 to form a gap between the sheet and the work receiver 15. Air is supplied to the air outlet 16 attached to the work receiver 15, and the sheet and the work receiver are supplied.
A gap 22 is formed in 15. This gap 22 has a hole diameter to be processed into a ceramic green sheet during laser processing,
The air flow rate is adjusted so that the gap 22 of at least 200 μm or more is formed without affecting the hole shape. This gap is not necessarily limited to this value, but the processing hole is not affected at the time of processing, and the uniform processing hole diameter,
The distance is set so that the hole shape can be machined and that the work receiver 15 does not cause clogging.

Next, the formed gap 22 is measured by the sensor 17, and the measured data is transmitted to the control device 26. The gap 22 suitable for processing is formed from the measurement data, that is, the air flow rate is adjusted so that the laser processing focal position is constant at a predetermined position. The air flow rate is controlled by the air valve 23 provided with a flow rate adjusting mechanism by the control device 26, for example, the air valve 23 provided with a function of finely adjusting the air flow rate by an electromagnetic valve. At this time, the air flow rate is adjusted so that a constant gap 22 is obtained over the entire surface of the ceramic green sheet or at least in the scanning region of the biaxial scan mirror 9 for processing. This adjustment is performed by independently adjusting the air valves 23 that supply air to the respective outlets 16, or, for example,
By adjusting an arbitrary area such as a range of 20 mm, it is possible to keep the processing focal position of the ceramic green sheet constant. By controlling the air flow rates of the individual air outlets 16 in this manner, the surface accuracy is maintained at high accuracy, and high-precision drilling is enabled.

[0018] Ceramic green sheet and work receiver 15
After the gap 22 is adjusted, laser light is irradiated from above the sheet to start drilling. Since a drilled hole is formed by drilling, the workpiece
The air supplied from the outlet flows out. Therefore, the ceramic green sheet and the work receiving
It is impossible to maintain a constant gap 22 by breaking the equilibrium of fifteen. For example, in the portion where the processing hole is formed, the air pressure for floating the sheet decreases due to the outflow of air, and the gap 22 decreases. However, since the gap 22 in the unprocessed portion does not change, the sheet is tilted, the surface accuracy is reduced, and the processed hole diameter and the processed hole diameter are affected, resulting in an uneven shape. Further, the accuracy of the machined hole position is also reduced due to the decrease in the surface accuracy. Therefore, during processing, the gap 22 is measured, and the valve 22 is controlled by the control device 26 to finely adjust the air flow rate so that the processing focal length during processing is always kept constant. And obtain high surface accuracy. Thus, in the present invention, (1) real-time measurement of the gap 22 during processing, (2) air flow analysis to maintain a constant gap using the measurement result, (3) through the process of air flow adjustment Drilling enables high-speed and high-precision processing. By setting the accuracy of the processing focal position by this process within ± 50 μm, the processing holes and the hole shape are made uniform, and high hole position accuracy is realized. If the processing accuracy can be reduced by the hole pitch, the hole diameter, and the like of the processing pattern, the processing time can be further reduced by shortening the processing focus positioning time.

During processing, a processing residue generated by laser irradiation is removed by a dust collector provided above the work receiver 15. Since the apparatus has a structure in which air is blown out from the work receiver 15 in the direction of the ceramic green sheet, the processing residue is pushed upward along with the air together with the air, and the processing residue shown in FIG.
Is suppressed. Further, since the processing residue flows above the sheet, the processing residue on the lower surface of the sheet can be suppressed. In addition, the ceramic green sheet is
And the air are held in a non-contact state, so that uniform hole diameters and hole shapes can be machined without being affected by work receiving, such as a pilot hole explosion that has occurred at the work receiving contact area. it can.

When the processing is completed, the irradiation of the laser beam is stopped, the blowing of the air is also stopped, and the pins 19 fixing the sheet frame 21 are released.

When a laser having a high energy density is irradiated during processing, even if a gap 22 which does not affect the hole diameter and hole shape of the electronic circuit board is formed, the work receiver 15 is irradiated with the laser. May be damaged.
Therefore, by using a material having a high transmittance with respect to the laser beam for the work receiving portion to which the air outlet 16 and the gap sensor 17 are attached, it is possible to suppress damage during high energy density laser irradiation, Compared to a conventional contact-type work receiver using a rod-shaped member or a pin, the durability of the work receiver 15 can be improved, and the running cost of the laser processing apparatus can be reduced.

Although the air outlet 16 has a circular shape in the embodiment of the present invention, it is not necessarily limited to this shape. As the air outlet 16, for example, even when a linear one having a width of several mm is applied, by controlling the air flow rate of each outlet so that the processing unit maintains a predetermined processing focal position, The effects of the present invention can be sufficiently exhibited. In addition, since the processing focal position accuracy and the control of the air outlet 16 are different depending on the type of the electronic circuit board and the processing pattern, the apparatus sets the parameters according to each substrate type and pattern in advance, thereby performing the processing. It is possible to speed up the control.

[0023]

As described above, in the drilling of an electronic circuit board such as a ceramic green sheet by a laser, a certain gap is formed between the electronic circuit board and the work receiver by air blown from the work receiver. ,
By making the work receiver and the electronic circuit board non-contact, a uniform hole diameter and hole shape can be obtained without being affected by the work receiver at the time of processing. Is possible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cross-sectional shape of a laser drilling.

FIG. 2 is a schematic diagram of a laser processing apparatus.

FIG. 3 is a schematic view of a work receiver.

FIG. 4 is a schematic top view of a work receiver.

FIG. 5 is a diagram illustrating a procedure for processing a ceramic green sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser light, 2 ... Ceramic green sheet, 3 ... Working hole, 4 ... Work hole explosion, 5 ... Clogging, 6 ... Laser oscillator, 7 ... Expander, 8 ... Mask, 9 ... 2-axis scan mirror, 10… fθ lens, 11… XY stage, 12…
Work receiver, 13: electronic circuit board, 14: control device, 15: work receiver, 16: air outlet, 17: gap sensor,
18… Positioning pin, 19… Fixed pin, 20… Electronic circuit board,
21 ... Fixing jig, 22 ... Gap, 23 ... Air valve, 24 ...
Piping, 25 signal line, 26 control device, 27 air supply device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B23K 101: 42 B23K 101: 42 (72) Inventor Tsutomu Shibuya 1st Horiyamashita, Hadano-shi, Kanagawa Hitachi Server Enterprise Server Division (72) Inventor Mikio Hongo 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Hitachi, Ltd. Production Engineering Research Laboratory F-term (reference) 4E068 AF00 CA17 CC00 CE09 CG01 DA11

Claims (2)

[Claims] In a device for irradiating a laser beam from a laser oscillator to pierce an electronic circuit board, by providing a mechanism for blowing air to a work receiver, which is an electronic circuit board installation portion, a gap between the substrate and the work receiver is provided. And a laser processing device provided with a mechanism for controlling the air flow rate with a sensor so that the gap is maintained at a constant distance. 2. The method according to claim 1, wherein a real time measurement of a gap formed between the work receiver and the electronic circuit board, which is an electronic circuit board installation portion, is performed during processing, and an air flow rate is adjusted through a control device during processing. Laser processing equipment with a mechanism to keep the gap during processing constant.