JPH08174259A - Laser machining method and its device - Google Patents

Abstract

PURPOSE: To greatly improve machining speed by having a substrate surface irradiated with a laser beam through the innermost tube of a double conical tube, making an assist gas flow between the innermost tube and the outer tube and blowing it to the substrate surface. CONSTITUTION: The wavelength of a beam generated by a carbon dioxide laser device is selected through grating and controlled into a single wavelength. The laser beam with the single wave length is converged with a lens and emitted to the surface of the substrate 18 through the inner tube 17b of the double conical tube. The diameter of the inner tube 17b is 1 to 3.5mm, and a distance between the end of the exit and the surface of the substrate 18 is made 1mm or more. An assist gas with the pressure of 1kg/cm<2> or higher is made to flow between the inner tube 17b and the outer tube 17a and blown to the surface of the substrate 18. By separating the passage of the laser beam transmission from that of the assist gas, the heat energy density is held high on the area of the diameter (d) on the surface of the substrate 18 irradiated with the laser beam; and the outer circumference is cooled by the assist gas so as to bring in the steep distribution of heat energy density.

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 apparatus for irradiating a carbon dioxide laser beam on a substrate material to smoothly cut the substrate material or to form slits or grooves.

[0002]

2. Description of the Related Art In recent years, glass material substrates and magnetic material substrates,
Product development of electrical or optical integrated circuits in which electronic circuits or optical circuits are mounted on or in semiconductor material substrates, or dielectric material substrates, or electrical / optical integrated circuits in which electricity and light are integrated It has become active. The integrated circuit is densely integrated in a range of several tens to several tens of thousands on a circular or square substrate having a size of about 3 inches to 10 inches. Then, each integrated circuit is cut and separated from the substrate. As the cutting / separating method, as shown in FIG. 6, a method of performing diamond blade dicing on the substrate 18 according to the alternate long and short dash line, or performing a scribing by irradiating a laser beam is used.

FIG. 7 shows a schematic view of a method of cutting glass by carbon dioxide (CO ₂ ) laser irradiation and an apparatus therefor proposed by the present inventor. This is CO ₂
An assist gas introducing pipe 17 is provided around the laser beam L of the laser 1.
When the glass substrate 18 on the fixing base 19 is irradiated with the assist gas G by passing through the glass substrate 18 and the glass substrate 18 is cut into two substrates A and B, Fixed stand 19 on each side
A method and apparatus for cutting the glass substrate 18 while vacuum adsorbing and fixing the same on the glass substrate 18.

[0004]

However, when the multi-component glass substrate or the ceramic substrate is cut or the grooves or slits are formed by using the apparatus shown in FIG. 7, the following problems occur. I understood.

(1) In order to blow away fine particles of glass or ceramics that have been vaporized or vaporized during processing, a gas inlet pipe 17
The assist glass G is introduced from above and is blown onto the surface of the substrate 18 being processed. However, when the flow rate of the assist gas G is low, fine particles remain on the edges of the front and back surfaces of the cut substrate 18, so-called dross. Was found to occur.
Therefore, the flow rate of assist gas must be increased (the gas pressure at the assist gas outlet is in the range of 3 kg / cm ² to 5 kg / cm ² ). However, when the flow rate of the assist gas is increased, the thermal energy of the substrate processing surface due to the laser light irradiation is gradually reduced, and the cutting or processing speed must be reduced. That is, it caused a decrease in productivity. This is because, as shown in FIG. 1 (a), since the propagation path of the laser light L and the path of the assist gas G are the same in the conventional method, the substrate surface where the energy density is highest due to the laser light irradiation is the assist gas. It was caused by the fact that it was cooled by and caused a decrease in energy density.

(2) As shown in FIG. 1 (a), since the assist gas is blown to the laser focusing surface (within the diameter d) on the substrate surface, the thermal energy distribution on the substrate surface is widened, which causes Microcracks were generated on the front and back surfaces of the cut substrate, and further on the side surfaces due to thermal deformation strain.

It is an object of the present invention to provide a method of processing a substrate material and an apparatus therefor for solving the above-mentioned problems of the prior art. That is, 1) to obtain a dross-free cut surface or a processed surface, 2) to increase the cutting or processing speed to improve productivity, and 3) to obtain a cut surface or a processed surface without microcracks. , To achieve. In addition to the above-mentioned object, the present invention is capable of cutting or processing in a dry and clean atmosphere, since it is non-contact cutting or processing, there is no contamination of the substrate and water is not sprayed,
It goes without saying that it is possible to expect that the electrical or optical characteristics of the substrate will not be damaged.

[0008]

In order to achieve the above object, the present invention has the following constitution.

According to a first aspect of the present invention, the wavelength of light oscillated by a carbon dioxide gas laser device is selected by a grating and controlled to a single wavelength, the laser light of this single wavelength is condensed by a lens, and then at least a double cone is formed. While irradiating the substrate surface through the inner tube of the tube and flowing the assist gas between the inner tube and the outer tube of the double conical tube so as to blow it onto the substrate surface, the substrate is moved in the X or Y direction. This is a method of processing a substrate that is moved to the next position.

A second invention is the processing of the substrate according to the first invention, wherein the gas pressure of the assist gas blown out from the at least double conical tube has a value of at least 1 kg / cm ^2. Is the way.

According to a third invention, in the first and second inventions, the diameter of the inner tube of the at least double conical tube is in the range of 1 mm to 3.5 mm, and the exit end of the double conical tube and the substrate. A substrate processing method is characterized in that the distance from the surface is at least 1 mm.

A fourth invention is a method of processing a substrate according to the first to third inventions, wherein the assist gas is allowed to flow in the inner tube of the at least double conical tube in the propagation direction of the laser light. .

In a fifth aspect based on the first to fourth aspects, the carbon dioxide gas laser device is kept in an oscillating state at all times, and the opening / closing with a mirror for blocking or passing the laser light between the carbon dioxide gas laser device and the condenser lens is performed. When processing the substrate, place the instrument on the substrate and adjust the power of the carbon dioxide laser device so that the power reflected by the mirror is monitored by the laser power sensor when the laser light is blocked and the power is constant. In the method of processing a substrate, the switch is opened to allow laser light to pass therethrough.

According to a sixth aspect of the present invention, in the first to fifth aspects, a substrate moving mechanism for moving the substrate is provided, and the substrate moving mechanism is integrally fixed on the vibration isolator together with the carbon dioxide laser device. Is a substrate processing method.

According to a seventh aspect of the present invention, in the first to sixth aspects, a region in which the substrate is processed is used as an assist gas atmosphere, and the enclosed region is forcibly exhausted through an exhaust duct pipe. The substrate processing method is characterized in that

The eighth invention is a carbon dioxide gas laser device having an external resonator with a grating capable of selectively controlling the wavelength, and a system for converging the wavelength-controlled laser light from the device and irradiating the substrate material. And covering the passage of the laser light until the laser light is condensed by the lens and irradiated onto the substrate material with at least a double conical tube, and an assist is provided between the inner tube and the outer tube of the double conical tube. It is a substrate material processing apparatus comprising a system for flowing a gas and blowing it onto the surface of a substrate material, and an apparatus for moving the substrate material in at least the X or Y direction.

A ninth aspect of the present invention is a substrate material processing apparatus configured to introduce gas into the inner tube of a double conical tube.

A tenth aspect of the invention is the opening and closing with a mirror according to the eighth and ninth aspects, which can be operated between the carbon dioxide gas laser device and the condenser lens so as to block or pass the laser beam by an electrical signal. Of a substrate material having a system for monitoring the light reflected by the mirror with a laser power sensor when the laser beam is cut off and a system for adjusting the power supply of the carbon dioxide laser device by the output signal from the monitoring system. It is a processing device.

In an eleventh aspect of the present invention based on the eighth to tenth aspects, at least a carbon dioxide laser device, a switch with a mirror, a condenser lens system, a double conical tube, and a substrate moving mechanism are integrated on a vibration isolator. It is an apparatus for processing a substrate material, which is characterized by being realized.

[0020]

The basic idea of the present invention is to devise such that the substrate surface having the highest energy density by laser irradiation is not cooled by the blowing of the assist gas. That is, as shown in FIG. 1B, the diameter d (= 100) of the substrate surface irradiated with the laser light is changed by making the propagation path of the laser light and the path of the assist gas different.
(within μm) area, the thermal energy density of the area is kept at a maximum, and the outer peripheral portion of the area with the diameter d (100 μm) is cooled by blowing an assist gas, and the outer peripheral direction is extended from the center of the laser light irradiation area. It has a very steep thermal energy density distribution. By providing such a rapid thermal energy density distribution, first of all, the cutting or processing speed of the substrate can be increased. Secondly, since the outer peripheral portion of the area irradiated with the laser light is cooled by the assist gas, it is possible to suppress the generation of microcracks due to so-called thermal deformation strain, which is caused by deformation of the substrate edge due to melting. Thirdly, in the configuration of the present invention, the flow rate (or pressure) of the assist gas is
Since the decrease in the thermal energy density in the laser beam irradiation area is small even if the value is increased, the adhesion of dross can be suppressed and a uniform cut surface or processed surface can be obtained. Fifthly, the laser light is controlled so that only light of a single wavelength is selectively output, and the heat energy density of the irradiation area is kept very high. It is possible to suppress the generation of irregularities on the cut surface or the processed surface due to the wavelength dependence.

[0021]

EXAMPLE FIG. 2 shows a first example of a substrate material processing apparatus according to the present invention. This device is a carbon dioxide laser device 1 to which an external grating portion 2 which is an external resonator is externally attached.
The output laser light L _{1 is applied} to the shutter 11 and the mirror 14.
An optical system for irradiating the surface of a substrate material 18 made of a non-metallic material such as glass or ceramics with a lens 15 through the gas, a gas introduction pipe 17 for flowing the assist gas G and G ₂ , and a substrate material. It comprises a substrate material moving device 20 with a fixed base 19 for moving 18 at least in the X or Y direction. The carbon dioxide gas laser device 1 uses the mixed gas 7 (CO
₂ , carbon dioxide gas laser tube 6 enclosing a mixed gas of N ₂ , He at a ratio of 8:18:74, a Brewster window 9, an internal mirror 4, an external grating portion 2, an electrode 8a and 8b is housed in a box.
Here, the oscillation spectrum of the laser beam L ₁ oscillated and output from the carbon dioxide gas laser device 1 has a so-called conventional configuration in which the Brewster window 9 is formed by an internal mirror without the external grating portion 2. In this case, resonance occurs between the internal mirror and the internal mirror 4 attached to the other side of the carbon dioxide laser tube 6, and the light is output from the output extraction hole 5, so that the output light has a wavelength of 9.1 μm to 11 μm. It oscillates over a wide wavelength range of 0.3 μm, and the power oscillating at each wavelength also has a distribution. This wide oscillation spectrum distribution and its power distribution adversely affect the cutting of the substrate material. On the other hand, in the device configuration of the present invention, the oscillation spectrum of the laser beam L ₁ that is oscillated and output is the angle adjustment unit 3 that adjusts the angle θ of the external grating unit 2.
By changing the angle θ by rotating the micrometer, it becomes possible to selectively extract and output only light of a single wavelength (for example, 10.6 μm) from the above wavelength range. There is. The electrode 8a
Reference numerals 8b are electrodes for applying a voltage for causing a discharge necessary for causing population inversion in the carbon dioxide laser tube 6. The carbon dioxide laser tube 6 is not shown,
It is a double tube, and the outer circumference of the carbon dioxide laser tube 6 is water-cooled. The laser beam L ₁ output from the carbon dioxide gas laser device 1 reaches the shutter 11. Here, a mirror is attached to the shutter 11, and when the laser beam L ₁ is blocked by the electric drive system 12, the laser beam L ₁ is reflected by the mirror of the shutter 11 and L
It is input to the optical power meter 13 as shown in ₂ . The output of the optical power meter 13 is fed back to the power supply circuit 10 of the carbon dioxide gas laser device 1 as shown by the arrow C, and the power supply voltage of the power supply circuit 10 (not shown).
By adjusting the output value of the optical power meter,
That is, the values of L ₁ and L ₂ are controlled to be constant. With the value of the laser light power kept constant and controlled to a single wavelength, the electric drive system 12
Is operated to open the shutter 11, and the laser light L ₁ is focused on the surface of the substrate material 18 by the lens 15 via the mirror 14. In this case, the distance f from the lens 15 to the surface of the substrate material 18 is made to substantially match the focal length of the lens 15.

A laser beam L is formed on the surface of the substrate material 18.
_The assist gas is always introduced from the gas introduction pipe 17 when the light ₄ is focused. Here, the gas introducing pipe 17 is a triple conical pipe 17a, 17 in this embodiment.
b and 17c. And assist gas G
_As shown in FIG. 1 (b), ₂ is made to flow so as to be different from the propagation path of the laser beam L ₁ . That is, the laser beam L ₁ is blown onto the outer periphery of the irradiation area d. The gas pressure needs to be at least 1 kg / cm ² , and the higher the gas pressure (3 to 6 kg / cm ² ), the more suitable it is to suppress the generation of dross and the generation of microcracks. The assist gas G ₁ is used to prevent the surface of the lens 15 from being contaminated, and has a very small flow rate (several tens ml / min to several l / min).
Good. Further, the gas introduction pipe 17 is preferably installed at a distance g from the surface of the substrate material 18. Here, the value of g is the inner diameter D ₁ of the exit end of the laser beam L ₄ of the gas introduction pipe 17.
Small enough (1.5mmφ~3.5mmφ) is small, D ₁
The larger the value, the larger. The range of g is 0.5 mm to 5
mm is preferred. The substrate material 18 is fixed on a fixed base 19, and the fixed base 19 is provided with a groove 21 so that the laser beam L ₅ can penetrate therethrough. As described above, the substrate surface having the highest energy density by laser irradiation is configured not to be cooled by blowing the assist gas. This makes it possible to provide a very steep thermal energy density distribution from the center of the laser light irradiation area toward the outer peripheral direction.

As a result of cutting the 1.1 mm thick soda glass substrate 18 using the above-mentioned device, the carbon dioxide laser device 1
When the optical power of the laser beam L ₁ is 70 W, the cutting speed of 5 mm / sec is the upper limit value in the conventional device, but when the device of the present invention is used, the cutting speed of 7.5 mm / sec to 8 mm / sec is increased. It was possible to cut at the cutting speed. Further, although the dross was considerably adhered in the conventional apparatus, it could be completely eliminated in the apparatus of the present invention by increasing the gas pressure of the assist gas G ₂ . As another glass substrate, a Pyrex glass substrate (trade name, 7059) manufactured by Corning
The same effect as that of the above-mentioned embodiment could be obtained by performing the same on a glass substrate having a thickness of 1 mm). Further, it was found that microcracks were also generated in the ones cut by the conventional device, and that the above-mentioned microcracks progressed and large cracks were generated at the edges of the cut substrates due to the passage of time and changes in environmental conditions. On the other hand, in the case of cutting with the device of the present invention, not only such cracks but also microcracks did not occur.

As another substrate, a mullite and alumina substrate having a thickness of 1 mm was used and the same cutting was performed. As a result, it was possible to improve the cutting speed and suppress dross and microcracks.

FIG. 3 shows an embodiment of the gas introduction pipe 17 used in the substrate material processing apparatus of the present invention. The same figure (a) is a front sectional view, (b) is a top view, and (c) is a bottom view. This gas introduction tube is composed of a triple conical tube, laser light propagates in the innermost tube 17a, and assists to prevent contamination of the lens 15 between the innermost tube 17a and the intermediate tube 17b. The gas is flushed. Between the intermediate tube 17b and the outermost tube 17c, an assist gas for forcibly cooling the substrate surface around the area irradiated with the laser light is flowed. Intermediate tube 17b
The inner diameter D ₁ of the nozzle 23 at the tip of is 1.5 mmφ to 3.5
The range of mmφ is preferable. Nozzle 2 at the tip of the outermost tube 17c
The inner diameter D ₂ of ₂ is set so that the gas pressure at the outlet of the nozzle 22 can be at least 1 kg / cm ² , and at most about 8 kg / cm ² . This gas inlet pipe has 3
In addition to the heavy conical tube, a double tube or a tube having four or more tubes may be used.

FIG. 4 shows a second substrate material processing apparatus according to the present invention.
An example of is shown. In this device, the carbon dioxide laser device 1, the optical system, the gas introduction pipe 17, and the substrate material moving device 20 are fixed on a vibration isolation table 25 having a vibration isolation mechanism. The carbon dioxide gas laser device 1 is fixed on a vibration isolation table 25 by using posts 24a and 24b. By fixing the substrate material 18 on the anti-vibration table in this way, it is possible to cut the substrate material 18 with an accuracy of the order of μm, and to form grooves, slits, or the like.

FIG. 5 shows a third embodiment of the substrate material processing apparatus of the present invention.
FIG. This encloses a box 26 around the substrate material 18 being processed,
6 is exhausted by the exhaust device 27. Thus, it is possible to have a role of exhausting the fine particles of the substrate material ordered during processing, a role of exhausting the assist gas, and a role of protecting the surface of the substrate material being processed with the assist gas atmosphere.

[0028]

According to the present invention described above, the following excellent effects are exhibited.

(1) In particular, cutting a substrate made of a non-metal material,
The speed of forming a groove or slit can be significantly improved.

(2) It is possible to obtain a cut surface without dross or a processed surface.

(3) It is possible to obtain a cut surface or a processed surface without microcracks.

(4) The productivity can be improved and the cost required for cutting or processing can be reduced.

[Brief description of drawings]

1A is a principle and a schematic view of a conventional cutting method, and FIG. 1B is a principle and a schematic view of a cutting method of the present invention.

FIG. 2 is a schematic view of an embodiment of a substrate material processing apparatus of the present invention.

FIG. 3 is a schematic view of an embodiment of a gas introduction pipe used in the substrate material processing apparatus of the present invention.

FIG. 4 is a schematic view of an embodiment of a substrate material processing apparatus of the present invention.

FIG. 5 is a schematic view of an embodiment of a substrate material processing apparatus of the present invention.

FIG. 6 is a plan view of a substrate material for explaining a method of cutting / separating an integrated circuit.

FIG. 7 is a schematic view of a glass cutting device by irradiation of carbon dioxide laser light previously proposed by the present inventor.

[Explanation of symbols]

 1 Carbon dioxide laser device 2 External grating section 3 Angle adjusting section 4 Internal mirror 5 Output extraction hole 6 Carbon dioxide gas laser tube 8 Electrode 9 Brewster window 11 Shutter 13 Optical power meter 14 Mirror 15 Lens 17 Gas introduction tube 18 Substrate 19 Fixing stand 20 Substrate material transfer device 25 Anti-vibration table L Laser light G Assist gas

Claims (11)

[Claims] 1. A wavelength of light oscillated by a carbon dioxide gas laser device is selected by a grating to be controlled to a single wavelength, and the laser light of this single wavelength is condensed by a lens, and then the innermost portion of at least a double conical tube. Irradiate the substrate surface through a tube, and
While the assist gas is made to flow between the innermost tube and the outer tube of the heavy conical tube and blown onto the substrate surface, X,
Alternatively, the laser processing method is characterized by moving the substrate in the Y direction to process the substrate. 2. The laser processing method according to claim 1, wherein the gas pressure of the assist gas blown out from the at least double conical tube is 1 kg / cm ² or more. 3. The diameter of the inner tube of the at least double conical tube is
3. The laser processing method according to claim 1, wherein the distance is 1 mm to 3.5 mm, and the distance between the exit end of the double conical tube and the substrate surface is 1 mm or more. 4. The assist gas also flows in the inner tube of the at least double conical tube in the propagation direction of the laser light.
The laser processing method described. 5. A carbon dioxide laser device is always in an oscillating state,
A switch with a mirror that blocks or passes the laser light is placed between the carbon dioxide laser device and the condenser lens, and when the laser light is blocked, the light reflected by the mirror is monitored by the laser power sensor. 5. The power supply of the carbon dioxide laser device is adjusted so that the power is constant, and when the substrate is processed, the switch is opened to allow the laser light to pass therethrough. The laser processing method according to item 1. 6. A substrate moving mechanism for moving the substrate is provided, and the substrate moving mechanism is integrally fixed on a vibration isolator together with the carbon dioxide gas laser device.
5. The laser processing method according to claim 1. 7. A substrate processing region is surrounded by an assist gas atmosphere, and the enclosed region is forcibly exhausted through an exhaust duct pipe. The laser processing method according to claim 1. 8. A carbon dioxide gas laser device having an external resonator with a grating capable of selectively controlling the wavelength, a system for converging the laser light having the wavelength controlled from the device and irradiating the substrate, and the laser light. Cover the path of the laser beam until the light is condensed by the lens and irradiate the substrate with at least a double conical tube,
It is characterized by comprising a system for flowing an assist gas between the inner tube and the outer tube of the double conical tube and blowing it on the surface of the non-metallic material, and a device for moving the substrate in at least the X or Y direction. And laser processing equipment. 9. The laser processing apparatus according to claim 8, wherein the gas is also introduced into the inner tube of the at least double conical tube. 10. A switch with a mirror that can be operated so as to cut off or pass the laser beam by an electric signal is provided between the carbon dioxide gas laser device and the condenser lens, and when the laser beam is cut off, 10. The laser processing apparatus according to claim 8, further comprising a system for monitoring the light reflected by the mirror with a laser power sensor, and a system for adjusting the power supply of the carbon dioxide laser device by an output signal from the monitoring system. 11. A carbon dioxide laser device, a switch with a mirror, a condenser lens system, a double conical tube, and a substrate moving mechanism are integrated on a vibration isolator. 9. The laser processing device according to 9 or 10.