JP2001176820A - Method for machining substrate and machining device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machining method and its machining device which can part a substrate with high accuracy of size, without its position shift or pitching in or after machining. SOLUTION: A crack is made in the substrate by having its top surface irradiated with a laser beam and developed to part of the substrate. By this method, grooves 21 and 25 are previously formed on the irradiation track of the laser beam 2-3 and irradiated with the laser beam 2-3 while a cooling medium is blown, thereby splitting the substrate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a substrate made of a nonmetallic material such as ceramics, glass or semiconductor.

[0002]

2. Description of the Related Art A technique of cutting a non-metallic material substrate such as ceramics, glass or semiconductor into square chips of several mm to several tens of mm with high dimensional accuracy has been regarded as important.

As this kind of cutting method, a dicing method or a method of applying a stress and then applying a crack after scribing with a scriber has been used.

In recent years, a substrate surface is irradiated with a CO ₂ laser beam to generate a crack due to thermal stress, and the crack is propagated along a CO ₂ laser beam irradiation locus, thereby cutting the substrate. A way to do this is also being considered.

Furthermore, a method of forming a continuous scribe line on one or both surfaces of a glass substrate and irradiating the scribe line with a laser beam to cut the glass substrate (Japanese Patent Laid-Open No. 3-258)
No. 476), or a cutting groove is partially formed on the outer periphery of a plate made of a brittle material, and the cutting groove is partially moved while moving the cutting heating body along a cutting target line starting from this groove. In the cleaving method in which the cleaving of the plate body is advanced from the starting point, a method in which fine processing grooves are formed in advance on the surface of the plate body by a diamond tool, injection processing or the like (Japanese Patent Laid-Open No.
No. 21673).

Therefore, the present inventor studied the division of the substrate using a CO ₂ laser beam using an apparatus shown in FIG.

FIG. 7 is a conceptual diagram of a substrate cutting device.

[0008] The cutting apparatus, CO ₂ laser apparatus 1 is incident vertically with the total reflection mirror 3 and CO ₂ laser beam 2 proceeds horizontally from, the substrate 6 by flying a CO ₂ laser beam 2 by the condenser lens 4 To be irradiated. This substrate 6 has X
It is placed on the vacuum suction stage 80 on the Yθ stage 100, and is evacuated by the vacuum exhaust device 9 through the vacuum suction holes 7 to be vacuum-adsorbed on the vacuum suction stage 80.

The substrate 6 is divided into chips by moving the XYθ stage 100 in the X, Y, and θ directions by a motor drive unit (not shown). When the substrate 6 is cut into chips, assist gas (N ₂ , A ₂₎ is applied in the directions of arrows 5-1 and 5-2 along the irradiation direction of the CO ₂ laser beam.
r, O ₂ , air, etc.)
The generation of thermal deformation distortion on the analysis surface of the substrate 6 is suppressed.

[0010]

However, the conventional substrate cutting method has the following problems.

That is, when the substrate is cut into a lattice shape to obtain chips of 1 mm square to tens of mm square by the method using the apparatus shown in FIG. The substrate could not be cut with precision.

Here, the reason why the substrate cannot be cut with high dimensional accuracy will be described with reference to FIG.

FIG. 8 is a plan view of a fixing portion of a substrate used in the apparatus shown in FIG.

The substrate 6 is vacuum-adsorbed on a vacuum adsorption stage 80, and the substrate 6 is irradiated with a CO ₂ laser beam.
To the cutting lines 11-1, 11-2, 11-3, 11-4, 1
When the cutting line 11-6 is formed by cutting at 1-5 and then cutting in a grid shape, the cutting lines 11-5, 11-4, 1
Each of intersections 12-1, 1-1, 1-3, 11-2, 11-1
It was found that cutting was performed with uneven displacement occurring in 2-2, 12-3, 12-4, and 12-5.

That is, the cutting lines 11-1 to 11-
5, the substrate 6 forms the cutting lines 11-1 to 11-5 despite the fact that the substrate 6 is vacuum-sucked on the vacuum suction stage 80 by the plurality of vacuum suction holes 7. As a result, a gap of several tens of μm to 300 μm was formed between each of the divided substrate pieces.

The degree of the gap varies depending on the vacuum suction force, the gas pressure of the assist gases 5-1 and 5-2, and the like. When the cutting lines 11-6 are formed in a state where such gaps are formed, the intersections 12-1 to 12-5 of the respective cutting lines are non-uniformly shifted (not orthogonal cutting lines but non-orthogonal cutting lines). Cutting line), and a square (or rectangular) chip cannot be obtained.

An object of the present invention is to solve the above problems and to provide a substrate processing method and a processing apparatus capable of cutting a substrate with high dimensional accuracy without displacement or chipping of the substrate during or after processing. is there.

[0018]

In order to achieve the above object, according to the first aspect of the present invention, a crack is generated in a substrate by irradiating the surface of the substrate with a laser beam, and the crack is caused to propagate to the substrate. In the cutting method, a groove is formed in advance on a laser beam irradiation trajectory line, and the substrate is cut by irradiating a laser beam while spraying a cooling medium on the groove.

A second aspect of the present invention is the substrate processing method according to the first aspect, wherein water is used as a cooling medium.

According to a third aspect of the present invention, there is provided the method of processing a substrate according to the first aspect, wherein a liquid containing a coating material for absorbing a laser beam is sprayed as a cooling medium.

According to a fourth aspect of the present invention, there is provided the method of processing a substrate according to the first aspect, wherein a quenching gas is used as a cooling medium.

According to a fifth aspect of the present invention, there is provided the substrate processing method according to the fourth aspect, wherein the quenched gas contains a chemical which absorbs a laser beam.

The invention according to claim 6 is the substrate processing method according to claim 1, wherein a mixture of a liquid and a gas is used as a cooling medium, and the mixture contains a chemical absorbing a laser beam.

According to a seventh aspect of the present invention, the groove is formed by pressing a needle-shaped or roller-shaped metal projection having a sharp tip against the substrate surface, or by pressing the metal projection while rotating it to form a scribe line. 1 is a method for processing a substrate according to 1.

The invention according to claim 8 is the substrate processing method according to claim 1, wherein the groove is formed by subjecting the substrate to chemical etching.

According to a ninth aspect of the present invention, as the laser beam,
2. The substrate processing method according to claim 1, wherein a laser beam having a beam width wider than twice the groove width and a beam vertical width wider than 10 times the groove width is used.

According to a tenth aspect of the present invention, there is provided the substrate processing method according to the first aspect, wherein the substrate is cut into a lattice and divided into at least four chips.

According to the eleventh aspect of the present invention, the substrate is split by generating a split crack in the X direction or the Y direction, and the split substrate in the Y direction or the X direction is split by cleavage. Item 11. A substrate processing method according to Item 10.

According to a twelfth aspect of the present invention, the groove is provided in the vicinity of one end or the other end of the substrate, from one end to the other end, or in the vicinity of an intersection which is cut in a grid. It is a processing method of the substrate described.

According to a thirteenth aspect of the present invention, there is provided an apparatus for generating a crack in a substrate by irradiating the surface of the substrate with a laser beam and causing the crack to propagate to cleave the substrate. And a laser beam irradiation means for irradiating the groove with a laser beam, a cooling medium spraying means for spraying a cooling medium in advance on the groove to be irradiated with the laser beam, and a moving means for moving the substrate. is there.

According to a fourteenth aspect of the present invention, there is provided the substrate processing apparatus according to the thirteenth aspect, wherein the cooling medium blowing means blows water or steam as a cooling medium into the groove.

According to a fifteenth aspect of the present invention, there is provided the substrate processing apparatus according to the thirteenth aspect, wherein the cooling medium spraying means sprays a cooling medium containing a coating material for absorbing a laser beam into the groove.

The invention according to claim 16 is the substrate processing apparatus according to claim 13, wherein the cooling medium blowing means blows a quenching gas as a cooling medium into the groove.

The invention according to claim 17 is the apparatus for processing a substrate according to claim 16, wherein the cooling medium spraying means sprays a cooling medium containing a chemical absorbing a laser beam into the quenched gas.

In a preferred embodiment of the present invention, the cooling medium spraying means uses a mixture of liquid and gas as the cooling medium in the groove, and the mixture contains a chemical which absorbs a laser beam. This is a substrate processing device.

According to a nineteenth aspect of the present invention, the groove forming means comprises a needle-shaped or roller-shaped metal projection having a sharp tip.
14. The substrate processing apparatus according to claim 13, wherein the metal projection is pressed against the substrate surface or pressed while rotating to form a scribe line.

According to a twentieth aspect of the present invention, there is provided the substrate processing apparatus according to the thirteenth aspect, wherein the groove forming means forms a groove in the substrate by chemical etching.

According to a twenty-first aspect of the present invention, in the laser beam irradiation means, the laser beam whose horizontal width is within twice the groove width and the vertical width of the laser beam is expanded to ten times or more the groove width is applied to the substrate. The substrate processing apparatus according to claim 13, wherein the irradiation is performed.

According to a twenty-second aspect of the present invention, the moving means includes at least X, Y, and θ for dividing the substrate into a lattice.
The substrate processing apparatus according to claim 13, further comprising a mechanism capable of moving in a direction.

According to a twenty-third aspect of the present invention, the groove forming means can be formed in the vicinity of one end or the other end of the substrate, from one end to the other end, or in the vicinity of an intersection which is cut in a grid. Item 14. A substrate processing apparatus according to item 13.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a substrate processing apparatus according to the present invention. In FIG. 1, components having the same reference numerals as those in FIG. 7 have the same functions.

Reference numeral 1 denotes a CO ₂ laser oscillator in the present embodiment.
A laser oscillator, a harmonic (second or third harmonic) oscillator of a YAG laser, an excimer laser oscillator, or the like can be used.

The laser beam 2-1 from the CO ₂ laser oscillator 1 is bent at a right angle by the total reflection mirror 3, and the laser beam 2-2 is guided to the condenser lens 4. Condensing lens 4
The laser beam passed through is guided to a cylindrical rod (cylindrical rod of ZnSe) 20 and a linear beam (length L, width Wb) 2
Converted to -3. The length L of the linear beam 2-3 is set on the cutting line of the substrate 6 and is set in a groove formed in advance. And the length L is 1 of the groove width Wm.
It can be expanded more than 0 times. Also, the width Wb of the linear beam 2-3
Is narrowed down to less than twice the groove width Wm.

The substrate 6 is placed on a porous plate 13 provided on a work table 80, and the porous plate 13
Is vacuum-adsorbed onto the porous plate 13 through a vacuum exhaust port 14 and a vacuum exhaust device 9 below the vacuum pump.

That is, the porous plate 13 has 10
It is a ceramic or metal vacuum suction plate provided with a myriad of pores of about μm to about 100 μm, and can suction the substrate 6 with a high degree of vacuum suction.

The work table 80 is provided on a moving device 100 which can move in the XYZθ directions, and is moved in the direction of the arrow 15-2 (or 15-1) in this figure.

Reference numeral 16 denotes a metal projection having a sharp tip for forming a groove on the substrate 6 in advance. For example, a needle-shaped or roller-type rotating chisel made of carbide, a thin blade diamond grindstone, or the like is used. Reference numeral 17 denotes a processing mechanism for applying a desired pressure to the metal projection 16.

Numeral 18 denotes a nozzle for spraying a cooling medium (liquid or gas or a mixture of liquid and gas) into a groove formed by the metal projections 16, and 19 denotes a cooling medium to be fed into the nozzle 18. It is an arrow which shows a sending direction.

Referring to FIG. 1, specific examples of forming a groove, spraying a cooling medium in the groove, and irradiating a laser beam into the groove will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 2 shows a state in which a groove 21 is formed on the substrate 6.
A specific example of a method of spraying a liquid 22 into the formed groove 21 and thereafter irradiating a laser beam 2-3 to cut the substrate 6 along the groove 21 is shown.

The substrate 6 is fixed on the work table 80 by vacuum suction and is moved at a desired speed in the direction of arrow 15-2.

The metal projection 1 shown in FIG.
6, a groove (width Wm) 21 is formed. Immediately thereafter, a liquid 22 is sprayed into the groove 21 as a cooling medium by the nozzle 18. As the liquid 22, a liquid that absorbs laser energy such as water, water vapor, ink (colored ink such as black, blue, and green), and oil-based coating liquid (colored coating liquid such as black, blue, and green) is used.

Immediately after spraying the liquid 22, the laser beam 2-3 is applied. This laser beam 2-
3 is preferably a linear beam having a length L and a width Wb.
Alternatively, an elliptical beam may be used.

There are three advantages of spraying the liquid 22. One is an effect of accelerating a crack in the groove 21 by cooling. Second, the laser beam 2-3 is applied to the groove 21.
The absorption of the liquid 22 in the liquid has an effect of further promoting the split crack. The third function is to blow and remove particles generated in the groove 21. It is also effective when the substrate 6 that is difficult to absorb the laser beam 2-3 is cut. Further, the present invention is also effective when a laser beam 2-3 whose laser beam 2-3 is hardly absorbed by the substrate 6 is used.

FIG. 3 shows an example in which a gas 23 is blown instead of the liquid 22 as the cooling medium in FIG.

Here, as the gas 23, a refrigerant gas having a temperature of 0 ° C. or less, a gas containing a coating agent, or the like is used. When the laser beam 2-3 is irradiated immediately after the cooling by blowing the refrigerant gas, a larger temperature difference can be provided, so that a crack is generated and the cost is reduced, and the cutting speed can be reduced.

FIG. 4 shows an example of spraying the mixture 24 instead of spraying the liquid 22 as the cooling medium in FIG.

As the mixture 24, for example, a mixture of the above-mentioned ink and paint which is transported by He or N ₂ gas having a dew point of −20 ° C. or less is used. In this way, it is expected that the laser beam 2-3 can be easily cut by promoting the absorption effect, and the cooling effect can be improved in the cutting speed.

FIG. 5 shows another embodiment of the substrate processing apparatus of the present invention.

The present embodiment is suitable for an apparatus for cleaving a substrate 6 in which a groove is formed in advance by a chemical etching method (dry or wet etching method).

That is, this apparatus is not provided with the groove forming means for the metal projection 16 shown in FIG.

A feature of the substrate cutting using the apparatus shown in FIG. 5 is that there is no generation of particles. Since the grooves are formed with high dimensional accuracy by a chemical etching method using a photomask in advance, a chip with high dimensional accuracy can be obtained by cutting.

It is desirable that the groove is formed up to the end of the substrate 6.

FIG. 6 shows grooves 25-1 to 25-18 formed by the above-described chemical etching method in a lattice pattern. Then, while spraying, for example, a liquid 22 as a cooling medium onto these grooves 25-1 to 25-18, a laser beam 2-3 is irradiated immediately thereafter to generate a cleavage crack and cause the substrate 6 to break. It was done.

The substrate 6 used in the present invention includes glass (quartz, multi-component), magnetic material (ceramics, YIG, etc.),
A semiconductor (Si, GaAs, InP, or the like) or a crystal (sapphire, LiNbO ₃ , LiTaO _5, or the like) can be used. Note that an electronic circuit, an electronic component, an optical circuit, an optical component, or the like may be formed in, on, or on the surface of the substrate.

In FIG. 6, for example, the cutting by the irradiation of the laser beam 2-3 is performed only in the X direction of the grooves 25-1 to 25-9, and is performed for the grooves 25-10 to 25-19 in the Y direction. May be divided by cleavage under mechanical stress.

An example of the substrate 6 is a substrate on which a semiconductor laser is formed. Since the input and output end faces of the semiconductor laser need to realize a desired high reflectance,
Both end faces conventionally formed by cleavage are used as input / output end faces. Therefore, in the case of FIG.
5-10 to 25-18 should be split by cleavage,
Used as input / output end face.

In FIGS. 2, 3, 4 and 6, the groove may be formed near one end or the other end of the substrate, instead of being formed from one end to the other end of the substrate. Alternatively, it may be provided in the vicinity of the intersection part cut in a lattice shape. Further, an assist gas may be blown along the irradiation direction of the laser beam 2-3.

The width Wm of the groove is preferably in the range of several tens μm to 100 μm, and the depth of the groove is also preferably a value similar to the above value.

It is desirable that the inside diameter of the nozzle 18 is as small as possible. For example, in the case of ejecting a liquid, it is possible to eject the ink in the groove accurately by making it possible to eject an extremely fine ink like an ink jet system. Can be.

[0072]

In summary, according to the present invention, the following effects can be obtained.

(1) The substrate can be cut into minute sizes with high dimensional accuracy.

(2) The chip thus cut does not cause chipping, and the chip corner can be cut at a right angle.

(3) The cutting speed can be increased.

(4) A substrate that is difficult to cut can also be cut.

(5) By irradiating a laser beam while cooling, residual stress due to thermal strain on the substrate can be suppressed.

(6) Since the laser beam is applied to almost the inside of the groove, the substrate is cut along the groove faithfully. Further, since the cooling medium (liquid, gas, or mixture) is blown into the grooves, the cutting can be performed at higher speed. Furthermore, the cleaning of the fractured surface can be performed by spraying a cooling medium.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of cutting a substrate in the present invention.

FIG. 3 is a diagram showing a specific example of cutting a substrate in the present invention.

FIG. 4 is a diagram showing a specific example of cutting a substrate in the present invention.

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing a specific example of cutting a substrate in the present invention.

FIG. 7 is a view showing a conventional substrate processing apparatus.

FIG. 8 is a view showing a specific example of cutting a conventional substrate.

[Explanation of symbols]

 2-3 Laser beam 6 Substrate 16 Metal projection 18 Nozzle 21, 25 Groove

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Claims (23)

[Claims] In a method of irradiating a laser beam to a substrate surface to generate a crack in the substrate and growing the crack to cleave the substrate, a groove is formed in advance on a laser beam irradiation trajectory line. A method for processing a substrate, wherein the substrate is cut by irradiating a laser beam while blowing a cooling medium into the groove. 2. The substrate processing method according to claim 1, wherein water is used as the cooling medium. 3. The substrate processing method according to claim 1, wherein a liquid containing a coating material that absorbs a laser beam is sprayed as a cooling medium. 4. The method according to claim 1, wherein a quenching gas is used as the cooling medium. 5. The method for processing a substrate according to claim 4, wherein the quenching gas contains a chemical which absorbs a laser beam. 6. The substrate processing method according to claim 1, wherein a mixture of a liquid and a gas is used as the cooling medium, and the mixture contains a chemical which absorbs a laser beam. 7. The substrate according to claim 1, wherein the groove is formed by pressing a needle-shaped or roller-shaped metal projection having a sharp tip against the surface of the substrate, or by pressing the metal projection while rotating the substrate. Processing method. 8. The method according to claim 1, wherein the groove is formed by performing chemical etching on the substrate. 9. The substrate processing method according to claim 1, wherein the laser beam has a beam width wider than twice the groove width and a beam length wider than 10 times the groove width. 10. The substrate is cleaved in a grid, and at least 4
2. The method according to claim 1, wherein the substrate is divided into chips. 11. The substrate according to claim 10, wherein the substrate is divided by generating a cleavage crack in the X direction or the Y direction, and the division of the divided substrate in the Y direction or the X direction is performed by cleavage. Processing method. 12. A groove is provided near one end or the other end of the substrate.
2. The substrate processing method according to claim 1, wherein the substrate is provided from one end to the other end, or in the vicinity of an intersection part cut in a grid. 13. An apparatus for irradiating a laser beam onto a substrate surface to generate a crack in the substrate, and to propagate the crack to cleave the substrate, wherein a groove forming means for forming a groove in the substrate;
Laser beam irradiation means for irradiating the groove with a laser beam, cooling medium spraying means for spraying a cooling medium in advance on the groove to be irradiated with the laser beam, and moving means for moving the substrate; Processing equipment. 14. The substrate processing apparatus according to claim 13, wherein the cooling medium blowing means blows water or steam as a cooling medium into the groove. 15. The substrate processing apparatus according to claim 13, wherein the cooling medium spraying means sprays a cooling medium containing a coating material for absorbing a laser beam into the cooling medium. 16. The substrate processing apparatus according to claim 13, wherein the cooling medium blowing means blows a quenching gas as a cooling medium into the groove. 17. The substrate processing apparatus according to claim 16, wherein the cooling medium spraying means sprays a cooling medium containing a chemical absorbing the laser beam into the quenched gas. 18. The substrate processing apparatus according to claim 13, wherein the cooling medium spraying means uses a mixture of a liquid and a gas as a cooling medium in the groove, and the mixture contains a chemical absorbing a laser beam. 19. The groove forming means comprises a needle-shaped or roller-shaped metal projection having a sharp tip, and presses the metal projection against the substrate surface or presses the metal projection while rotating to form a scribe line. A substrate processing apparatus according to the above. 20. The substrate processing apparatus according to claim 13, wherein the groove forming means forms a groove in the substrate by chemical etching. 21. A laser beam irradiating means for irradiating a substrate with a laser beam having a laser beam having a lateral width of not more than twice the groove width and a vertical width of the laser beam expanding to be at least ten times the groove width. A substrate processing apparatus according to the above. 22. The substrate processing apparatus according to claim 13, wherein the moving means has a mechanism capable of moving at least the substrate in the X, Y, and θ directions so that the substrate can be cut into a lattice shape. 23. The groove forming means can be formed in the vicinity of one end or the other end of the substrate, from one end to the other end, or in the vicinity of an intersection which is cut in a grid pattern.
4. The substrate processing apparatus according to 3.