WO2004014625A1

WO2004014625A1 - Method and device for scribing fragile material substrate

Info

Publication number: WO2004014625A1
Application number: PCT/JP2003/009899
Authority: WO
Inventors: Masahiro Fujii; Shuichi Inoue
Original assignee: Mitsuboshi Diamond Industrial Co.,Ltd.
Priority date: 2002-08-09
Filing date: 2003-08-04
Publication date: 2004-02-19
Also published as: JP4080484B2; JPWO2004014625A1; TWI277612B; KR100649894B1; TW200403193A; KR20050018636A; CN1298523C; CN1638931A; AU2003252389A1

Abstract

A method for scribing a fragile material substrate, comprising the steps of cooling a mother glass substrate (50) in an area in proximity to laser spots (LS) along a predicted scribe line (SL) while continuously radiating laser beam onto the surface of the mother glass substrate (50) so that the laser spots (LS) with a temperature lower than the softening point of the mother glass substrate can be formed along the predicted scribe line (SL) to form a main cooling spot (MCP), whereby cracks can be continuously formed along the predicted scribe line (SL), and an assist cooling spot (ACP) for pre-cooling an area positioned on the laser spot (LS) side of the main cooling spot (MCP) can be formed along the predicted scribe line (SL) in proximity to the main cooling spot (MCP).

Description

Technical Field of Scribing Method and Scribing Device for Brittle Material Substrate

In the present invention, a scribe line is formed on the surface of a brittle material substrate in order to cut a brittle material substrate such as a glass substrate or a semiconductor wafer Λ used in a flat panel display (hereinafter referred to as FPD). It relates to rice scribing and scribing equipment. Background art

The following describes the conventional technology for forming scribe lines on a glass substrate, which is a type of brittle material substrate used in various flat panel displays, and a mother brittle material substrate that is formed by bonding the brittle material substrates together. To do. An FPD such as a liquid crystal display panel, which is composed of a pair of glass substrates, is bonded to each other, and then each mother glass substrate has a predetermined size that constitutes the FPD. It is divided so that it may become a glass substrate. Each mother glass substrate is cut along a scribe line after a scribe line is formed in advance by a diamond cutter or the like. Depending on the type of flat panel display and the manufacturing method, a scribe line may be formed on the mother glass substrate before bonding, and the mother glass substrate may be divided. When the scribe line is mechanically formed by force etc., the formed scribe line

) The peripheral part is in a state where the residual stress is accumulated. When the mother glass substrate is divided along the skirt: residual stress is accumulated at the edge portion of the side edge and the peripheral portion of the surface of the glass substrate formed by the division. Such residual stress is caused by unnecessary clans and socks near the surface of the glass substrate. When this residual stress is released, unnecessary cracks may occur and the edge of the glass substrate may be broken. Fragments generated by chipping of the edge of the glass substrate's cross section may adversely affect the manufactured FPD.

In recent years, a method using a laser beam has been put into practical use in order to form a scribe line on the surface of a mother glass substrate. In the method of forming a scribe line on a mother glass substrate using a laser beam, the laser beam LB is irradiated from the laser oscillator 61 to the mother glass substrate 50 as shown in FIG. The The laser beam LB emitted from the laser oscillation device 61 forms an elliptical laser spot LS along the planned scribe line SL on the mother glass substrate 50 on the surface of the mother glass substrate 50. To do. The mother glass substrate 50 and the laser beam LB irradiated from the laser oscillation device 61 are relatively moved along the longitudinal direction of the laser spot LS.

The mother glass substrate 50 is heated by the laser beam LB to a temperature lower than the temperature at which the mother glass substrate 50 is softened. Thereby, the surface of the mother glass substrate 50 on which the laser spot LS is formed is heated without being softened. In addition, a cooling medium such as cooling water is sprayed from the cooling nozzle 62 so that a scribe line is formed near the irradiation region of the laser beam LB on the surface of the mother glass substrate 50. It is summer. A compression stress is generated on the surface of the mother glass substrate 50 irradiated with the laser beam LB by heating with the laser beam LB, and a tensile stress is generated by spraying a cooling medium. As described above, tensile stress is generated in a region adjacent to the region where the compressive stress is generated, and therefore, a stress gradient based on each stress is generated between the two regions, and the mother glass substrate 50 has a mother glass. A vertical crack is formed in the thickness direction (vertical direction) of the mother glass substrate 50 along the planned scribe line SL from the notch TR formed in advance at the end of the substrate 50. That is, this vertical crack line is Prine.

The vertical cracks formed on the surface of the mother glass substrate 50 in this way are so minute that they are usually invisible to the naked eye, so they are called blind cracks B C.

Figure 9 shows a mother glass substrate scribed by a laser scribing device.

FIG. 10 is a plan view schematically showing a physical change state on the mother glass substrate 50. FIG.

The laser beam oscillated from the laser oscillator 61 forms an elliptical laser spot L S on the surface of the mother glass substrate 50. The laser spot L S is irradiated so that the long axis coincides with the scribe line S L.

In this case, in the laser spot L S formed on the mother glass substrate 50, the thermal energy intensity at the outer peripheral edge is larger than the thermal energy intensity at the center. Such a laser spot LS is formed by making a laser beam having a Gaussian distribution of thermal energy into a thermal energy distribution such that each end in the major axis direction has the maximum thermal energy intensity. . Therefore, at each end in the major axis direction located on the planned scribe line SL, the thermal energy intensity is maximized, and the thermal energy intensity of the center portion of the laser spot LS sandwiched between each end is It is smaller than the thermal energy intensity at each end.

The mother glass substrate 50 is relatively moved along the long axis direction of the laser spot LS. Therefore, the mother glass substrate 50 is moved along the planned scribe line SL by the laser. After heating with a large thermal energy intensity at one end in the long axis direction of the spot LS, it is heated with a small thermal energy intensity at the center of the laser spot LS, and then applied with a large thermal energy intensity. Be heated. Then, after that, the cooling medium is sprayed from the cooling nozzle 62 to the cooling point CP on the scribe line with a predetermined interval L in the long axis direction from the rear side end of the laser spot LS, for example. As a result, a temperature gradient is generated between the laser spot LS and the cooling point CP, and a large tensile stress is generated in a region opposite to the laser spot LS with respect to the cooling point CP. Then, using this tensile stress, a vertical crack is formed in the direction of the thickness t of the mother glass substrate 50 along the planned scribe line from the cut TR formed at the end of the mother glass substrate 50. Is done.

The mother glass substrate 50 is heated by an elliptical laser spot L S. In this case, in the mother glass substrate 50, heat is transferred three-dimensionally from the surface toward the inside due to the large thermal energy intensity at one end of the laser spot LS. By moving relative to one glass substrate 50, the portion heated by the front end portion of the laser spot LS is heated again by the small thermal energy intensity at the center portion of the laser spot LS, and then again. The laser spot LS is heated by a large intensity of heat energy at the rear end of the laser spot LS.

In this way, after the surface of the mother glass substrate 50 is heated by the large thermal energy intensity, the heat is reliably conducted to the inside while being heated by the small thermal energy intensity. . At this time, the surface of the mother glass substrate 50 is prevented from continuing to be heated by a large thermal energy intensity, and the surface of the mother glass substrate 50 is prevented from being softened. After that, when the mother glass substrate 50 is heated again with a large heat energy strength, the mother glass substrate 50 is surely heated to the inside, and the surface of the mother glass substrate 50 is heated. Compressive stress is generated inside and inside. A tensile stress is generated by spraying the cooling medium onto the cooling point CP in the vicinity of the region where the compressive stress is generated.

When a compressive stress is generated in the heating area by the laser spot LS and a tensile stress is generated at the cooling point CP by the cooling medium, the cooling is caused by the compressive stress generated in the thermal diffusion area between the laser spot LS and the cooling point CP. For Boynt CP Thus, a large tensile stress is generated in a region opposite to the laser spot LS. Then, using this tensile stress, a blind crack is generated along the scribe line from the cut TR formed in the end portion of the mother glass substrate 50. Once formed, the mother glass substrate 50 is supplied to the next cutting step, and a bending moment that causes the blind crack BC to extend in the thickness direction of the mother glass substrate 50 on both sides of the blind crack BC. A force is applied to the mother glass substrate 50 so as to generate. As a result, the mother glass substrate 50 is divided along the blind crack BC formed along the scribe line SL.

In such a scribing apparatus, the laser spot LS formed on the surface of the mother glass substrate 50 has a heat energy intensity distribution that maximizes the heat energy intensity in the major axis direction. In this way, the thermal energy intensity is maximum at each end in the major axis direction, and the surface of the mother glass substrate 50 is heated in two stages, so that the mother glass substrate 50 is placed inside the substrate. Heat is transferred. Therefore, a sufficient thermal stress gradient cannot be obtained with the cooling point CP only by cooling with the refrigerant forming the cooling point CP, and a deep blind crack (vertical crack) is not formed. For this reason, there was a risk of causing a separation failure of the mother glass substrate 50 in the aforementioned separation step.

In such a case, it is necessary to slow the relative movement speed of the mother glass substrate 50 and the laser spot LS, and to increase the heating time by the end of the laser spot LS. There is a risk that BC cannot be formed efficiently.

The present invention solves such a problem, and its object is to scribe a brittle material substrate by which a scribe line can be efficiently and reliably formed on a brittle material substrate such as a mother glass substrate. And to provide a scribing device. Disclosure of the invention

The brittle material substrate scribing method according to the present invention is such that a laser spot is continuously formed along a planned scribe line on the surface of the brittle material substrate so that a laser spot having a temperature lower than the softening point of the brittle material substrate is formed. A cooling spot is formed by cooling around the area along the planned scribe line behind the laser spot with a cooling medium, and a blind crack is formed along the planned scribe line. In the scribing method of the brittle material substrate formed continuously, at least one assist cooling spot for cooling the region in the laser spot side from the cooling spot along the planned scribe line with a coolant in advance is provided. It is characterized by scribing while forming. The assist cooling spot is formed by a refrigerant having a cooling temperature higher than the cooling temperature forming the cooling spot.

Further, the brittle material substrate scribing apparatus of the present invention moves while continuously irradiating a laser beam so that a laser spot having a temperature lower than the softening point of the brittle material substrate is formed on the surface of the brittle material substrate. A laser beam irradiating means and a cooling means for continuously cooling the vicinity of the region along the planned scribe line behind the region heated by the laser spot with a coolant, and scribing on the surface of the brittle material substrate. In a scribing apparatus for a brittle material substrate that forms a blind crack along a predetermined line, an area closer to the laser spot formed by the laser beam irradiating means than an area cooled by the cooling means is disposed on the cooling means. Equipped with at least one assisted cooling means that cools with a refrigerant having a temperature higher than that of the refrigerant. And it features. Brief Description of Drawings

FIG. 1 is a schematic plan view showing an implementation state of the scribing method of the present invention. FIG. 2 is a front view showing an example of the embodiment of the scribing apparatus of the present invention. FIG. 3 is a graph showing the results of forming blind cracks in Example 1.

FIG. 4 is a graph showing the result of forming a crack in Example 2.

FIG. 5 is a graph showing the result of forming a crack in Example 3.

FIG. 6 is a graph showing the result of forming blind cracks in Example 4.

FIG. 7 is a schematic plan view showing another embodiment of the present invention.

FIG. 8 is a schematic diagram for explaining the operation of a conventional laser scribing apparatus using a laser beam.

FIG. 9 is a perspective view schematically showing the state of blind crack formation on the mother glass substrate scribed by the laser scribing apparatus.

FIG. 10 is a plan view schematically showing a physical change state on the mother glass substrate scribed by the laser scribe device. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a schematic plan view of the surface of a mother glass substrate schematically illustrating an implementation state of the scribing method for a brittle material substrate according to the present invention. This scribing method is used, for example, when dividing a mother glass substrate to form a plurality of glass substrates constituting an FPD such as a liquid crystal display panel, before dividing the mother glass substrate. It is carried out to form blind cracks that become scribe lines.

As shown in FIG. 1, a laser spot LS 1 is formed on the surface of the mother glass substrate 50 by laser beam irradiation along a scribe line SL. Note that the scribe line SL on the surface of the mother glass substrate 50 A cut TR along the planned scribe line is formed in advance on the side edge of the mother glass substrate 50 near the tip start position.

The laser spot L S 1 has an elliptical shape, and is moved relative to the surface of the mother glass substrate 50 in the direction indicated by the arrow A in a state where the major axis is along the planned scribing line S L.

In this case, in the laser spot L S 1 formed on the mother glass substrate 50, the thermal energy intensity at the outer peripheral edge is larger than the thermal energy intensity at the center. Such a laser spot LS 1 is formed by making a laser beam having a Gaussian distribution of thermal energy into a thermal energy distribution in which each end portion in the major axis direction has a maximum thermal energy intensity. Therefore, the thermal energy intensity is maximized at each end in the major axis direction located on the scribe line SL, and the thermal energy intensity at the central portion of the laser spot LS 1 sandwiched between the ends is It is smaller than the thermal energy intensity at the edge.

The elliptical laser spot L S 1 moves along the scheduled scribe line S L on the surface of the mother glass substrate 50, and sequentially heats the scheduled scribe line S L.

The laser spot LS 1 heats the mother glass substrate 50 while moving at a high speed relative to the mother glass substrate 50 at a temperature lower than the softening point temperature at which the mother glass substrate 50 softens. To do. Accordingly, the surface of the mother glass substrate 50 on which the laser spot L S 1 is formed is heated without being melted.

A main cooling point MCP is formed on the surface of the mother glass substrate 50 behind the laser spot LS 1 in the traveling direction. Main cooling point MCP is the surface of the motherboard first glass substrate 5 0 from the cooling nozzle, the cooling water, water mixed fluid of the compressed air, compressed air, H e gas, N ₂ gas, a cooling medium such C_〇 ₂ gas By spraying, the surface of the mother glass substrate 50 is formed to be cooled. In the same direction as the laser spot LS 1 with respect to the mother glass substrate 50, the laser spot LSI is transferred. It is moved along the planned scribe line SL on the surface of the mother glass substrate 50 at a speed equal to the moving speed.

Also, on the surface of the mother glass substrate 50, an assist cooling point ACP is formed along the scheduled scribe line SIJ, in front of the main cooling point MCP in the traveling direction, in proximity to the main cooling point MCP. . Assisted cooling point A CP is the surface of the motherboard first glass substrate 50 from the cooling nozzle, spraying cooling water, water mixed fluid of the compressed air, compressed air, He gas, N ₂ gas, a cooling medium such C_〇 ₂ gas Thus, the surface of the mother glass substrate 50 is cooled in a state in which the temperature of the refrigerant blown to the assist cooling point ACP is higher than the temperature of the refrigerant blown to the main cooling point MCP. As is the case with the main cooling point MCP, the ASSIS 卜 cooling point ACP is also the same as the laser spot LS I with respect to the mother glass substrate 50, and at a speed equal to the moving speed of the laser spot LS 1 It is moved along the scheduled scribe line SL on the surface.

The surface of the mother glass substrate 50 is sequentially heated by the laser spot LS 1 along the scheduled scribe line SL, and immediately before the heated portion is cooled by the refrigerant forming the main cooling boiler MCP. The coolant that forms the cooling point ACP is cooled at a higher cooling temperature than the main cooling boiler ボ MC P, and then cooled to a cooling temperature that is lower than the assist cooling point AC P by the refrigerant that forms the main cooling point MCP. Is done.

When the mother glass substrate 50 is heated by the laser spot LS 1, a compressive stress is generated on the surface thereof. After that, the mother glass substrate 50 is once cooled by the refrigerant that forms the assist cooling point ACP, and then the main cooling point MCP is set. It is further cooled by the refrigerant that forms. As a result, a blind crack BC line deep in the vertical direction is formed along the planned scribe line.

The surface of the mother glass substrate 50 is heated and compressed by the laser spot LS 1. After the force is generated, tensile stress is generated by once cooling the surface of the mother glass substrate 50 by the refrigerant that forms the assist cooling point ACP. When the tensile stress is generated and further cooled by the refrigerant forming the main cooling point MCP, the surface of the mother glass substrate 50 is already in a state where the tensile stress has been generated. Therefore, the tensile stress generated by the cooling by the refrigerant that forms the main cooling point MCP is more likely to act on the surface of the mother glass substrate 50. Deep crack crack BC is considered to be formed.

Further, in the scribing method using the conventional laser shown in FIG. 10, the surface of the mother glass substrate 50 is heated with the laser spot LS, and then the cooling medium is sprayed on the surface of the mother glass substrate 50. Since the surface is cooled, it is considered that there is a useless thermal shock in forming blind cracks.

In the scribing method of the present invention, by providing the assist cooling point ACP between the main cooling point MCP and the laser spot LS 1, the above-mentioned wasteful thermal shock is alleviated and thermal shock is caused. It is thought that the energy that was lost was spent on the force to extend the blind crack.

When a blind crack as a scribe line is formed on the mother glass substrate 50, the mother glass substrate 50 is supplied to the next cutting process, and the blind crack is formed on both sides of the plinde crack. A force is applied to the mother glass substrate 50 so as to generate a bending moment that extends in the thickness direction of zero. Thereby, the mother glass substrate 50 is divided along the blind crack formed along the scribe line S IJ.

FIG. 2 is a schematic configuration diagram showing an embodiment of a scribing device for a brittle material substrate according to the present invention. The scribing apparatus of the present invention is an apparatus for forming a scribe line for dividing a mother glass substrate 50 into a plurality of glass substrates used for FPD, for example. As shown in Fig. 2, this scribing device is mounted on a horizontal base 1 1 The slide table 1 2 reciprocates along the horizontal direction (Y direction). Slide table 1 2 is slidable along a pair of guide rails 14 and 1 5 in a horizontal state on a pair of guide rails 14 and 15 arranged in parallel along the Υ direction on the top surface of the base 1 1 It is supported by. A pole screw 13 is provided at an intermediate portion between the guide rails 14 and 15 so as to be rotated by a motor (not shown) in parallel with the guide rails 14 and 15. The pole screw 13 can be rotated forward and backward, and is attached in a state where the ball nut 16 is screwed onto the pole screw 13. The pole nut 16 is integrally attached to the slide table 12 2 without rotating, and slides in both directions along the pole screw 13 by the forward and reverse rotation of the pole screw 1 3. As a result, the slide table 1 2 attached integrally with the pole nut 16 is slid along the guide rails 14 and 15 in the Υ direction.

On the slide table 1 2, a pedestal 19 is arranged in a horizontal state. The base 19 is slidably supported by a pair of guide rails 21 arranged in parallel on the slide table 12. Each guide rail 21 is arranged along the X direction perpendicular to the heel direction, which is the sliding direction of the slide table 12. In addition, pole screws 2 2 are arranged in the center between the guide rails 2 1 in parallel with the guide rails 21, and the pole screws 2 2 are rotated forward and reverse by the motor 2 3. Yes.

A pole nut 2 24 is attached to the pole screw 2 2 in a state where it is screwed. The ball nut 24 is integrally attached to the pedestal 19 so as not to rotate, and moves in both directions along the pole screw 2 2 by forward and reverse rotation of the pole screw 2 2. As a result, the base 19 slides in the X direction along each guide rail 21.

A rotating mechanism 25 is provided on the base 19, and a rotating table 26 on which the mother glass substrate 50 to be cut is placed on the rotating mechanism 25 is in a horizontal state. It is provided in a state. The rotating mechanism 2 5 rotates the rotating table 2 6 around the central axis along the vertical direction, and the rotating table 2 6 is set so that an arbitrary rotation angle is 0 with respect to the reference position. Can be rotated. On the turntable 26, a mother glass substrate 50 is fixed by, for example, a suction chuck. Above the turntable 26, a support base 31 is disposed at an appropriate distance from the turntable 26. The support base 31 is supported in a horizontal state at the lower end portion of the optical holder 33 arranged in a vertical state. The upper end of the optical holder 33 is attached to the lower surface of a mounting base 3 2 provided on the base 11. On the mount 3 2, a laser oscillator 3 4 that oscillates a laser beam is provided. The laser beam oscillated from the laser oscillator 3 4 irradiates the optical system held in the optical holder 1 3 3. Is done.

The laser beam oscillated from the laser oscillator 34 has a normal distribution of thermal energy intensity, and an elliptical laser as shown in Fig. 1 is formed by the optical system provided in the optical holder 33. On the mother glass substrate 50 placed on the rotary table 26, the spot LS 1 is set so that its long axis direction is parallel to the X direction as the moving direction of the rotary table 26. Irradiated.

On the support base 31, an assist cooling nozzle 41 is arranged facing the mother glass substrate 50 placed on the rotating table 26 6 at an appropriate interval with respect to the optical holder 33. Has been. The assist cooling nozzle 4 1 is provided with a cooling water, a mixed fluid of water and compressed air, a compression at a position behind the laser spot LS 1 formed on the mother glass substrate by the laser beam irradiated from the optical holder 33. A cooling medium such as air or He gas is blown.

Further, a main cooling nozzle 37 is disposed on the support base 31 at a distance of 4 mm or more with respect to the assist cooling nozzle 41. This main cooling nozzle 37 is provided with a cooling medium such as cooling water, a mixed fluid of water and compressed air, compressed air, and He gas at a position behind the mother glass substrate cooled by the assistant cooling nozzle 41. Like to spray It has become. The cooling temperature of the cooling medium sprayed from the main cooling nozzle 37 to the mother glass substrate 50 is lower than the cooling temperature of the cooling medium sprayed from the assist cooling nozzle 41 to the mother glass substrate 50. .

Further, on the support table 31, the mother glass substrate placed on the rotary table 26 on the opposite side of the main cooling nozzle 37 with respect to the laser spot LS 1 irradiated from the optical holder 33. Opposite to 0 0, a cutlet wheel 3 5 is provided. The force utter wheel 35 is arranged along the long axis direction of the laser spot LS 1 irradiated from the optical holder 33, and the mother glass substrate 5 placed on the rotating table 26. Cuts (cuts) in the direction along the scribe line at the side edge of 0.

The positioning of the slide table 12 and the base 19, the rotation mechanism 25, the laser oscillator 34, and the like are controlled by a control unit (not shown).

When blind cracks are formed on the surface of the mother glass substrate 50 using such a scribing device, first, information such as the size of the mother glass substrate 50 and the position of the scribe line is input to the control unit. Is done.

Then, the mother glass substrate 50 is placed on the rotary table 26 and fixed by the suction means. In such a state, the alignment marks provided on the mother glass substrate 50 are imaged by the C CD cameras 38 and 39. The captured alignment marks are displayed on the monitors 28 and 29, and the position information of the alignment marks on the mother glass substrate 50 is processed by the image processing apparatus.

When the rotary table 26 is positioned with respect to the support base 31, the rotary table 26 is slid along the X direction, and the planned scribe line at the side edge of the mother glass substrate 50 is cut. One wheel is opposed to 3-5. Then, the cutter wheel 35 is lowered, and a cut (cut) TR is formed at the side edge portion of the scribe line of the mother glass substrate 50. After that, the rotating table 26 is slid in the X direction along the scribe line, while the laser beam is oscillated from the laser oscillation device 34, and from the cooling nozzle 41, cooling water, etc. The cooling medium is injected, and cooling water is injected from the main cooling nozzle 37 together with the compressed air.

Laser oscillating device 3 Mother glass substrate 5 4

On top of 0, an elliptical laser spot L S 1 that is elongated along the X-axis direction is formed along the strike direction of the mother glass substrate 50. Then, behind the laser spot L S I, the cooling medium is blown from the assist cooling nozzle 41 along the planned scribe line to form an assist cooling pin A CP. Further, a cooling medium is sprayed from the main cooling nozzle 37 along the planned scribe line S L behind the assist cooling point A C P to form a main cooling boiler 卜 M C P.

As a result, as described above, the assist cooling point ACP is not adopted for the mother glass substrate 50 due to the stress gradient formed by the heating by the laser spot LS 1 and the cooling by the assist cooling point ACP and the main cooling point MCP. Compared with the conventional combination, vertical blind cracks are formed deeper.

When the blind crack is formed on the mother glass substrate 50, the mother glass substrate 50 is supplied to the next cutting step so that the bending moment acts in the width direction of the blind crack. A force is applied to the glass substrate. As a result, the mother glass substrate 50 is divided along the blind crack from the notch TR provided in the side edge portion thereof.

In the description of the embodiments so far, the main cooling point MCP and the assist cooling point ACP are directly connected to the cooling line SL from the main cooling nozzle 37 and the assist cooling nozzle 41 on the planned scribe line SL, respectively. For example, the main cooling nozzle 37 and the assist cooling nose are formed. 4 1 is equipped with a mechanism to move in the X and Y directions independently, and on the scribe line, the distance between the laser spot LS 1 and the assist 卜 cooling point AC 及び and the Assist 卜 cooling point ACP and main cooling point MCP It is preferable that the position of the assist cooling point ACP and the main cooling point MCP can be set at a position shifted from the planned scribe line.

In the embodiment of the present invention, the mother glass substrate of the liquid crystal display panel is described as an example of the brittle material substrate. However, the present invention includes a bonded glass substrate, a single plate glass, a semiconductor wafer, ceramics, and the like. It can also be applied to scribe processing. In the above description, the case where the thermal energy intensity at the outer peripheral edge of the laser spot LS 1 formed on the mother glass substrate 50 is larger than the thermal energy intensity at the center has been described. The thermal energy distribution of the laser spot LS 1 may have a Gaussian distribution.

Next, examples in which blind cracks are formed on a glass substrate under various conditions using this scribing apparatus will be described.

Blind cracks were formed by irradiating a soda glass substrate having a thickness of 3.0 mm with a laser beam oscillated from the laser oscillator 34 at 20 W. The laser spot LS 1 formed on the glass substrate has, for example, an elliptical shape with a major axis of 40 mm and a minor axis of 1.5 thigh, and a main cooling point MC formed by the refrigerant blown from the main cooling nozzle 37 P is located 85 mm away from the center of the laser spot LS 1, and the assist cooling point ACP formed by the refrigerant sprayed from the assist cooling nozzle 41 is the laser spot LS 1 side from the main cooling point MCP. Are formed at 10 mm positions.

A main cooling nozzle 37 having a nozzle tip inner diameter of 0.6 mm is used, and an assistant cooling nozzle 41 having a nozzle tip inner diameter of 0.8 mm is used. From the main cooling nozzle 37, a mixed fluid of water and compressed air is sprayed from a height of 5 mm to the surface of the glass substrate at a pressure of 0.5 MPa (flow rate: 1 OL / min). It has become. In addition, compressed air is sprayed from the assist cooling nozzle 41 at a pressure of 0.2 MPa (flow rate: 14 L / min) from a height of 1 mm to the surface of the glass substrate. Furthermore, the moving speed of the glass substrate was changed stepwise from 100 mmZs to 1 S OmmZs in steps of 1 OmmZ s to form blind cracks in the glass substrate, and the depth δ was measured. The results are shown in the graph in Fig. 3. For comparison, the depth δ of the blind crack of the joint that does not form the assist cooling point AC soot by the assist cooling nozzle 41 is also shown in the graph of FIG.

In this case, by forming the assist cooling point AC による by the assist cooling nozzle 41, the depth of the blind crack was about 10% deeper than when the assist cooling point AC P was not formed.

The glass substrate is a soda glass substrate with a thickness of 1.1 mm, and a mixed fluid of water and compressed air is injected from the main cooling nozzle 37 at a pressure of 0.5 MPa (flow rate: l OLZmin). Compressed air is also injected from the assist cooling nozzle 41 at a pressure of 0.2 MPa (flow rate: 14 LZmin), and the assist cooling nozzle 41 is spaced 7 mm from the main cooling nozzle 37. Arranged. The glass substrate moving speed was changed stepwise from 10 OmmZs to 40 Omm / s by 20 mm / s to form blind cracks in the glass substrate, and the depth δ was measured. The results are shown in the graph in Fig. 4. For comparison, the depth δ of the weld crack when the assist cooling point AC による is not formed by the assist cooling nozzle 41 is also shown in the graph of FIG.

Other implementation conditions are the same as in Example 1.

In this combination, the assistance cooling point AC by the assistance cooling nozzle 41 is also used. By forming, the depth of blind crack <5 was about 10% deeper than when no assist cooling point AC P was formed.

The position of the assist cooling point AC P by the assist cooling nozzle 41 is changed between 0111111 and 1 5111111 with respect to the main cooling point MCP by the main cooling nozzle 37, and the cooling medium is injected by the assist cooling nozzle 41. Except that the pressure was changed to 0. IMP a (flow rate: 7L / min), 0.2MPa (flow rate: 14LZmin) and 0.3MPa (2lL / min). A blind crack was formed under the same conditions as in Example 1, and the depth <5 was measured. The results are shown in the graph in Fig. 5.

In this case, the assist cooling point ACP is formed by forming the asis 卜 cooling point AC P on the glass substrate so that the distance between the Asis 卜 cooling nozzle 41 and the main cooling nozzle 37 is about 10 mm. The depth of blind crack <5 was about 10% deeper than when not.

The pressure at which the cooling medium is injected by the assist cooling nozzle 41 by changing the position of the assist cooling point AC P by the assist cooling nozzle 41 between 5 mm and 9 mm at the distance from the main cooling point MCP by the main cooling nozzle 37. Is changed to 0.1 MPa (7 L / min), 0.2 MPa (14 L / min) and 0.3 MPa (2 lL / min), as in Example 2. A blind crack was formed under the following conditions, and its depth δ was measured. The results are shown in the graph of Fig. 6.

In this case as well, the assist cooling point AC P is formed on the glass substrate so that the distance between the assist cooling nozzle 41 and the main cooling nozzle 37 is about 7 mm, thereby forming the assist cooling point AC P. Compared to the case of not, the depth δ of the crack was about 10% deeper. FIG. 7 is a schematic plan view showing another embodiment of the present invention. The laser beam oscillated from the laser oscillator 34 forms an elliptical laser spot LS 1 that is elongated along the X-axis direction along the scanning direction of the mother glass substrate 50 on the mother glass substrate 50. Is done. Then, behind the laser spot LS 1, the cooling medium is sprayed from the plurality of assist cooling nozzles 41 along the scheduled scribe line to form a plurality of assist cooling points A CP. Further, a cooling medium is sprayed from the main cooling nozzle 37 along the planned scribe line SL behind the plurality of assist cooling points AC P to form the main cooling point MCP.

The surface of the mother glass substrate 50 is sequentially heated by the laser spot LS 1 along the scheduled scribe line SL, and then the plurality of assist cooling is sequentially performed immediately before the heated portion is cooled by the main cooling point MCP. Point ACP is cooled at a temperature higher than the temperature of the refrigerant that forms the main cooling point MCP, and then the refrigerant that forms the main cooling point MCP is higher than the temperature of the refrigerant that forms the assist cooling point ACP. Is also cooled by the lower temperature.

When the mother glass substrate 50 is heated by the laser spot LS 1, a compressive stress is generated on the surface thereof. After that, the mother glass substrate 50 is once cooled by a plurality of assist cooling points AC P and then cooled by the main cooling point MCP. It is further cooled. This forms a blind crack line that is deep in the vertical direction along the planned scribe line.

In addition, in the conventional laser scribing method shown in FIG. 8, the surface of the mother glass substrate 50 is heated by the laser spot LS, and then the surface of the mother glass substrate 50 is cooled by spraying a cooling medium. It is thought that an unnecessary thermal shock has occurred in forming a land crack.

By providing multiple assist cooling points ACP on the laser spot LS 1 side from the main cooling point MCP, the above-mentioned useless thermal shock is alleviated. It is thought that the energy lost by the thermal shock was spent on the force to extend the blind crack, and by using multiple assist cooling points, the mother glass substrate was cooled sequentially. The generation of useless thermal shock can be eliminated, and deeper cracks (vertical cracks) can be formed than in the case where there is only one assist cooling boiler.

The cooling medium for forming the main cooling point and the assist cooling point on the glass substrate is the same as that for forming the one assist cooling point on the mother glass substrate, and will not be described in detail here.

As a configuration of the scribing device, for example, a mechanism in which the main cooling nozzle 37 and the plurality of assist cooling nozzles 41 are independently moved in the X direction and the Y direction, and the laser spot LS 1 on the planned scribe line is provided. The distance between the assist cooling point ACP located closest to the laser spot, the distance between the assist cooling point ACP and main cooling point MCP located closest to the main cooling point MCP, and the distance between multiple assist cooling points can be adjusted freely. Further, it is preferable that the positions of the plurality of assist cooling points ACP and the main cooling point MCP can be set at positions shifted from the scribe line.

As described above, the present invention is achieved by providing at least one assist cooling point between the laser spot on the mother glass substrate and the main cooling void. Industrial applicability

The brittle material substrate scribing method and apparatus according to the present invention, as described above, is between the laser spot formed on the surface of the brittle material substrate such as a mother-glass substrate and the main cooling spot, and Since the assist cooling spot is formed at a position close to the spot, the blind crack can be deeply formed, and therefore the blind crack can be efficiently formed.

Claims

The scope of the claims

1. A laser beam is continuously irradiated and moved so that a laser spot having a temperature lower than the softening point of the brittle material substrate is formed along a planned scribe line on the surface of the brittle material substrate. Scribing a brittle material substrate by forming a cooling spot by cooling the vicinity of the area along the planned scribe line behind the spot with a cooling medium, and continuously forming blind cracks along the planned scribe line In the method

A brittle material substrate that is scribed while forming at least one assist cooling spot on the laser spot side with respect to the cooling spot and along the planned scribe line with a coolant in advance. Scribe method.

2 The brittle material substrate scribing method according to claim 1, wherein the assist cooling spot is formed by a refrigerant having a cooling temperature higher than a cooling temperature of the refrigerant forming the cooling spot.

3. a laser beam irradiation means for continuously moving a laser beam so that a laser spot having a temperature lower than the softening point of the brittle material substrate is formed on the surface of the brittle material substrate;

Cooling means that continuously cools the vicinity of the region along the planned scribe line behind the region heated by the laser spot with a coolant forms blind cracks along the planned scribe line on the surface of the brittle material substrate. In a brittle material substrate scribing device,

At least one assist cooling means for cooling a region closer to the laser spot formed by the laser beam irradiation means than an area cooled by the cooling means with a coolant having a temperature higher than the temperature of the refrigerant of the cooling means.

A scribing apparatus for a brittle material substrate, comprising: