JP2002050849A - Method and device for laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for laser beam machining capable of preventing smear from being stuck to a substrate and improving productivity in hole drilling using laser. SOLUTION: The laser beam machining device 1 consists of a board 21 whose one surface is held by a board holding means 20, a laser irradiation means 30 for drilling a hole by irradiating the hole drilling position 22 of the board 21 with a laser beam (laser) 31a and a plasma gas feeding means 40 for feeding gas to the position 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and a laser processing apparatus, and more particularly to a laser processing method and a laser processing apparatus for drilling holes in a circuit board with a laser.

[0002]

2. Description of the Related Art In recent years, as circuit boards have become smaller and lighter,
There is a need for a through hole or a blind hole on a circuit board to have a diameter of 200 μm or less. When such an extremely small diameter through hole or blind hole is formed on a circuit board, the hole is formed using a laser such as a carbon dioxide gas laser.

[0003]

However, when a hole is formed using a laser on a substrate containing a large amount of carbon, such as a circuit board made of glass epoxy resin or a resin circuit board made of polyimide, the hole contained in the board is not included in the board. The sublimated or evaporated carbon is released into the air, and the carbon released into the air is cooled in the air, around the hole processing portion of the substrate, specifically, the front and back surfaces of the substrate, inside the hole, Attaches to the bottom of the blind hole. The adhered substance is called smear or debris, and has a problem of deteriorating electrical characteristics such as insulating properties and conductive properties of the substrate. Conventionally, the circuit board to which smear has adhered has been entirely inserted into a reduced-pressure plasma atmosphere to remove the smear by molecular chemistry. However, there is also a problem that the same processing time is required and the production efficiency is poor, even when a large number of holes are drilled in the substrate or when only a few holes are drilled.

Accordingly, an object of the present invention is to provide a laser processing method and a laser processing apparatus capable of preventing smear from adhering to a substrate and improving productivity in drilling using a laser.

[0005]

As a means for solving the above-mentioned problems, the present invention holds one side of a substrate by substrate holding means, irradiates a laser to a hole drilling position of the substrate, and discharges the plasma gas by the plasma gas. The hole is supplied to the drilling position and drilled.

In the present invention, a hole is formed by irradiating a laser to a hole processing position of a substrate, and a plasma gas is supplied to the hole processing position, and the plasma gas is generated from the substrate by laser irradiation and adheres around the hole processing position of the substrate. The smear thus formed can be removed from the substrate by performing a plasma treatment using a plasma gas.

It is preferable that a gap is provided between the substrate and the substrate holding means at a position corresponding to the hole processing position. This prevents smear from adhering to the substrate and prevents the substrate holding means from being damaged by laser irradiation.

Preferably, the periphery of the hole processing position of the substrate is covered with a mask. Accordingly, it is possible to prevent the temperature of the substrate from increasing due to the plasma gas being supplied around the hole processing position.

It is preferable that the plasma gas is supplied from the side of the substrate to which the laser is irradiated and the side opposite to the side. This makes it possible to remove the smear attached to the surface irradiated with the laser and the opposite surface.

It is preferable that the plasma gas is supplied to the hole processing position after the hole processing is completed. Thus, after the completion of the drilling, the smear adhering to the periphery of the drilling position of the substrate can be removed from the substrate by plasma processing with the plasma gas.

Further, as means for solving the above-mentioned problems, the present invention provides a substrate having one side held by a substrate holding means, and a laser irradiating means for irradiating a hole at a hole drilling position of the substrate with a laser. And a plasma gas supply means for supplying a plasma gas to the hole processing position.

Preferably, the substrate holding means has a gap at a position corresponding to a hole processing position on one surface of the substrate.

It is preferable that the substrate has a mask that covers a periphery of a hole processing position of the substrate where the plasma gas is supplied.

It is preferable that the plasma gas supply means supplies the plasma gas from the surface of the substrate to which the laser is irradiated and the opposite surface.

It is preferable that the plasma gas supply means supplies a plasma gas by the plasma gas supply means after completion of the hole processing by the laser irradiation means.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration diagram of a laser processing apparatus 1 according to the present invention. The laser processing apparatus 1 includes a substrate holding unit 20 and a laser irradiation unit 30.
And plasma gas supply means 40.

The substrate holding means 20 holds one surface of the substrate 21 on the upper surface, and the hole processing position 2 of the substrate 21 on the upper surface.
There is a gap 23 at a location corresponding to 2. Further, the substrate holding means 20 is moved in the plane direction by an XY table 24 provided therebelow.

The laser irradiation means 30 includes a laser oscillator 31
And a mirror 32 that totally reflects the laser beam 31a oscillated from the laser oscillator 31 and a condenser lens 33 that collects the totally reflected laser beam 31a. The laser irradiating means 30 forms a hole in the substrate 21 by condensing the laser beam 31a on the hole processing position 22 on the substrate 21 by the condenser lens 33.

The plasma gas supply means 40 is inserted into a cylindrical hollow nozzle 42 having a tapered nozzle tip 41 and a closed other end, and an electrode 43a provided on the outer peripheral surface of the hollow nozzle 42. Electrode 43b and a high-frequency power source 4 for generating a high frequency between these electrodes 43a and 43b.
4 and a mixed gas supply device 45 for supplying a mixed gas to the inside of the hollow nozzle 42. The high frequency power supply 44
Glow discharge is generated by applying a high frequency of about 10 kHz to 100 MHz between 3a and 3b. The mixed gas supply device 45 includes tanks 46a, b, and c containing argon gas, helium gas, and oxygen gas, respectively.
And a mixed gas pipe 47 communicating with the hollow nozzle 42. Argon gas, helium gas and oxygen gas supplied from the tanks 46a, b and c are supplied at a predetermined rate, for example, argon gas is supplied at a flow rate of 1 liter / min. The helium gas is mixed at a flow rate of 2 liters / minute and the oxygen is mixed at a flow rate of 50 cc / minute, and supplied to the hollow nozzle 42 through a mixed gas pipe 47.

The plasma gas supply means 40 reacts the mixed gas supplied from the mixed gas supply device 45 with the glow discharge generated in the hollow nozzle 42, generates a plasma gas, and generates the plasma gas at a pressure higher than the atmospheric pressure. The gas is ejected from the nozzle tip 41. The hollow nozzle 42 has a nozzle tip 41 that is 3 to 1 from the upper surface of the substrate 21.
The plasma gas ejected from the nozzle tip 41 is provided so as to be located at a distance of about 0 mm, and is sprayed onto a circular area having a diameter of about 3 to 5 mm on the substrate 21. Preferably, it is provided so as to coincide with the position 22.

Next, the drilling of the laser processing apparatus 1 having the above configuration will be described.

As shown in FIG. 2, a laser beam 31a is radiated by laser irradiation means 30 to a hole processing position 22 of the substrate 21 while plasma gas is blown onto the substrate 21 by a plasma gas supply means 40 to perform hole processing. Do.
At this time, the carbon 25 generated from the substrate 21 reacts with highly active oxygen contained in the plasma gas to become carbon dioxide or carbon monoxide and is released into the air. Absent. When the substrate 21 is subjected to through-hole processing, when the laser beam 31a is irradiated on the substrate holding means 20 when the substrate 21 is penetrated, the substrate 21 is damaged and spatter or vapor is generated, and these adhere to the substrate 21. By providing the gap 23, the substrate holding means 20 may be prevented from being damaged, and spatter or vapor may be prevented from adhering to the substrate 21. When a blind hole (a hole that does not penetrate) is formed in the substrate 21, such a gap 23 need not be provided.

Further, the substrate 21 is moved in a fixed direction by the XY table 24, and the laser beam 31a is intermittently irradiated while the plasma gas is being sprayed, so that the substrate 21 is arranged in a line as shown in FIG. 3
As shown in (b), the holes are drilled in a plurality of rows, so that smear does not adhere. Also, according to this method, the productivity is improved because only the plasma processing is performed on the periphery of the hole processing position on the substrate surface, as compared with the conventional plasma processing of the whole inside the decompression chamber.

As shown in FIG. 4, a position corresponding to the hole processing position 22 of the substrate 21 is opened and the hole processing position 22 is opened.
May be provided on the upper surface of the substrate 21. The mask 26 may be in contact with the upper surface of the substrate 21 or may have a slight gap between the mask 26 and the upper surface of the substrate 21. As a result, the plasma gas blown around the hole processing position 22 is blocked by the mask 26,
The temperature rise of the substrate 21 can be reduced, and high quality (flatness and dimensional accuracy) can be maintained.

Further, as shown in FIG. 5, two hollow nozzles 42 for spraying a plasma gas to the hole processing position 22 of the substrate 21 from the surface of the substrate 21 opposite to the surface irradiated with the laser may be provided. Good. Accordingly, it is possible to prevent the smear from adhering to the upper and lower surfaces of the substrate 21 when the through-hole is formed in the substrate 21 by the laser processing apparatus 1 described above.

The plasma gas supply means 40 may supply the plasma gas to the hole processing position 22 by the plasma gas supply means 40 after the hole processing by the laser irradiation means 30 is completed. Since the time required for plasma processing is shorter in the two steps as compared with the time required for laser drilling, efficiency is higher in terms of shortening the processing tact on the production system.

Also, by continuously drilling holes while moving the substrate 21 in a certain direction by the XY table 24 and connecting the holes, the substrate 21 can be subjected to laser scribing.

[0028]

As is clear from the above description, according to the present invention, a laser beam is applied to a hole processing position of a substrate to form a hole, and a plasma gas is supplied to the hole processing position.
Smear generated from the substrate by laser irradiation and attached to the periphery of the hole processing position of the substrate can be removed from the substrate by plasma processing with a plasma gas, preventing smear from adhering to the substrate and improving productivity. I can do it.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a laser processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing the laser processing apparatus of FIG. 1 at the time of drilling holes.

FIG. 3A is a plan view showing a substrate on which holes are continuously formed on a straight line. (B) is a plan view showing a substrate on which holes are continuously formed on a plurality of rows of straight lines.

FIG. 4 is an overall configuration diagram of a laser processing apparatus according to another embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a laser processing apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 20 Substrate holding means 21 Substrate 22 Hole processing position 30 Laser irradiation means 31a Laser beam (laser) 40 Plasma gas supply means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) // B23K 101: 42 B23K 101: 42 F term (reference) 4E068 AF01 AJ04 CF04 CG01 CH05 CJ01 CJ02 CJ04 DA11 5E343 AA02 AA17 AA18 EE01 EE36 FF23 GG04

Claims (14)

[Claims] 1. A laser processing method comprising: holding one side of a substrate by substrate holding means; irradiating a laser to a hole processing position of the substrate; and supplying a plasma gas to the hole processing position to perform the hole processing. . 2. The laser processing method according to claim 1, wherein a gap is provided between the substrate and the substrate holding means at a position corresponding to the hole processing position. 3. The laser processing method according to claim 1, wherein the periphery of the hole processing position of the substrate is covered with a mask. 4. The laser processing method according to claim 1, wherein the plasma gas is supplied from a side of the substrate to which the laser is irradiated and a side opposite to the side. 5. The plasma gas is supplied to the drilling position after the drilling is completed.
The laser processing method according to any one of the above. 6. The laser processing method according to claim 1, wherein the plasma gas supply unit supplies the plasma gas to the hole processing position at a pressure higher than the atmospheric pressure. 7. The laser processing method according to claim 1, wherein the plasma gas includes an inert gas and a reaction gas. 8. The laser processing method according to claim 7, wherein the inert gas is made of helium or argon. 9. The laser processing method according to claim 7, wherein the reaction gas comprises oxygen or hydrogen. 10. The laser processing method according to claim 1, wherein the substrate is made of a polymer material containing carbon. 11. A substrate holding means for holding one surface of a substrate, a laser irradiating means for irradiating a hole at a hole processing position on the substrate with a laser, and a plasma gas supply means for supplying a plasma gas to the hole processing position. A laser processing apparatus comprising: 12. The laser processing apparatus according to claim 11, wherein the substrate holding means has a gap between the substrate and the substrate holding means at a position corresponding to a hole processing position of the substrate. . 13. The laser processing apparatus according to claim 11, wherein the substrate has a mask that covers a hole processing position of the substrate where the plasma gas is supplied. 14. The plasma gas supply unit according to claim 11, wherein the plasma gas supply unit supplies the plasma gas from a surface of the substrate to which the laser is irradiated and an opposite surface of the substrate. The laser processing apparatus according to the above.