JP2008179501A - Substrate dividing method and electro-optical device manufacturing method - Google Patents

Abstract

A method of dividing a substrate that is not easily damaged by laser light when scribing using laser light and a method of manufacturing an electro-optical device are provided.
A substrate dividing method for cutting a first substrate along a scheduled cutting surface is provided. A slope forming step of forming a recess 39 having slopes 39b and 39c on one surface along the planned cutting surface 34b of the first substrate 34, and a laser beam 2 along the planned cutting surface 34b of the first substrate 34. Irradiation includes an irradiation step for forming the modified portion 41 and a dividing step for applying stress to the modified portion 41 to divide the first substrate 34. In the irradiation step, inclined surfaces 39b and 39c are formed. Irradiation is performed so that a part or all of the laser beam 2 is irradiated onto the inclined surfaces 39b and 39c from the surface opposite to the surface 34c.
[Selection] Figure 5

Description

  The present invention relates to a method for dividing a substrate and a method for manufacturing an electro-optical device, and more particularly to a method for preventing damage to a structure on a substrate.

Patent Document 1 discloses a laser scribing method for irradiating a substrate with laser light to form a modified region (hereinafter referred to as a modified portion) inside the substrate in order to cut a light-transmitting substrate with high quality. Has been. According to this, laser light having a pulse width of 1 μs or less is emitted and condensed inside the substrate by a condensing lens so that the peak power density at the condensing point is 1 × 10 ⁸ (W / cm ² ) or more. Thereby, the modified part by multiphoton absorption is formed inside the workpiece.

In this laser scribing method, the size of the modified portion formed inside the object to be processed or the modified portion formed from this depends on the characteristics of the condenser lens and the peak power density of the laser beam. Dependent. For example, in an embodiment in which the glass (thickness: 700 μm) disclosed in Patent Document 1 is cut using a YAG laser, the peak power density is approximately 1 × when the condensing lens has a numerical aperture of 0.55. At 10 ¹¹ (W / cm ² ), the size of the modified portion is approximately 100 μm. Further, when the peak power density is about 5 × 10 ¹¹ (W / cm ² ), it is about 250 μm. By forming the reforming portions in the substrate and pressing the reforming portions, the substrate can be divided along the reforming portions with good quality.

  A display device such as a liquid crystal display device is often formed by using a pair of substrates having a rectangular outer shape and disposing a liquid crystal or a light emitting element between the pair of substrates. In the manufacturing method, a method is widely adopted in which an element mother substrate on which a plurality of patterns corresponding to switching elements such as transistors and display elements are arranged and an opposing mother substrate on which patterns such as common electrodes are arranged are bonded together and divided. ing.

JP 2002-192371 A

  When a pair of substrates are joined and then scribed by irradiating the substrate with laser light, a part of the laser light is transmitted through the modified portion to be formed. Laser light that passes through the modified portion formed on the substrate located near the condenser lens irradiates the substrate located away from the condenser lens. When wirings, terminals, electrical elements, and the like are arranged on a substrate located at a location away from the condenser lens, the laser light that passes through the modified portion irradiates them. Wiring, terminals, and electrical elements irradiated with the laser light may be damaged by the laser light. As a result, damaged wiring, terminals, and electrical elements may not function properly.

  The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to provide a method for dividing a substrate and an electro-optical device that are not easily damaged by laser light when scribing using laser light. It is to provide a manufacturing method.

  In order to solve the above-described problem, a substrate dividing method according to the present invention is a substrate dividing method for cutting a first substrate along a planned dividing surface, and one of the substrates is divided along the planned dividing surface of the first substrate. A slope forming process for forming a slope on the surface, an irradiation process for forming a modified portion by irradiating a laser beam along the planned splitting surface of the first substrate, and applying stress to the modified portion, A dividing step of dividing the substrate, and in the irradiation step, irradiation is performed such that a part or all of the laser beam is irradiated onto the inclined surface from the surface opposite to the surface on which the inclined surface is formed. .

  According to this substrate cutting method, the laser beam is irradiated in the irradiation step. At this time, in order to form the modified portion, the laser light is condensed and irradiated on a condensing place in the first substrate. The laser beam that has passed through the converging location spreads and radiates from the condensing location. At least a part of the laser light emitted from the condensing place is irradiated onto the slope formed on the first substrate. Since the first substrate has a higher refractive index than in the atmosphere, at least a part of the laser light that irradiates the inclined surface is reflected at the boundary between the first substrate and the atmosphere.

  When the inclined surface is arranged so that the incident angle of the laser light reaching the boundary surface between the first substrate and the atmosphere from the first substrate is increased, the amount of laser light reflected by the inclined surface can be increased. Accordingly, the amount of laser light emitted from the planned dividing surface of the substrate is reduced. As a result, even when there is a structure that is damaged by the laser beam in a location facing the planned splitting surface, the amount of laser light that irradiates this structure is small, so the structure is damaged. Can be difficult.

  In the substrate dividing method according to the present invention, in the inclined surface forming step, a concave portion having at least two inclined surfaces is formed along the planned dividing surface of the first substrate, and in the irradiation step, the optical axis of the laser beam is the apex of the concave portion. Laser light is irradiated so as to pass through the vicinity.

  According to the method for dividing the substrate, the first substrate is arranged so that the two inclined surfaces form the recesses along the planned dividing surface. The laser light emitted from the condensing place is irradiated in a direction away from the planned splitting surface.

  Laser light is irradiated along the planned splitting surface, and irradiation is performed so that the laser light passes near the apex of the recess. And when placing the right slope on the right side of the recess and the left slope on the left side, the laser light that passes through the condensing location and radiates to the right side of the planned split surface irradiates the right slope, on the left side of the planned split surface. The emitted laser light irradiates the left slope. Since the concave portion is formed by the right slope and the left slope, the right slope faces the left side. Therefore, the incident angle at which the laser beam irradiating the right slope enters the slope is larger than that when there is no slope. And the laser beam which irradiates a right slope becomes easy to reflect on a right slope. Similarly, laser light that irradiates the left slope is easily reflected by the left slope.

  That is, both the laser light emitted to the right side from the condensing location and the laser light emitted to the left side are easily reflected in the first substrate by the inclined surface formed in the recess. As a result, it is possible to reduce the amount of laser light that irradiates a place facing the planned splitting surface.

  The substrate dividing method according to the present invention is such that, in at least one of the inclined surfaces, the angle between the inclined surface and the planned dividing surface is closer to the top of the recessed portion than the inclined surface far from the top of the recessed portion. And formed at an acute angle.

  According to this substrate dividing method, the angle between the inclined surface of the recess and the planned dividing surface is different depending on the location of the inclined surface. And the slope of the place near the vertex of a recessed part is formed in an acute angle with respect to the parting plan surface. When irradiating the substrate with the laser beam, after irradiating the laser beam so that the optical axis of the laser beam passes through the planned splitting surface, the laser beam is collected at a condensing place on the optical axis.

  Of the laser light emitted from the condensing location, the laser light traveling at an acute angle with respect to the optical axis irradiates a slope near the apex of the recess. At this time, since the slope near the apex of the concave portion is formed at an acute angle with respect to the optical axis, the laser light that irradiates the slope is easy to reflect because the incident angle increases on the slope. .

  Of the laser light emitted from the condensing place, the laser light traveling at a large angle with respect to the optical axis irradiates a slope far from the apex of the recess. At this time, the slope far from the top of the recess is formed at a large angle with respect to the optical axis, but the laser light that irradiates the slope at this location travels at a large angle with respect to the optical axis. The laser beam that irradiates is easily reflected because the incident angle increases on the inclined surface. Therefore, the laser beam can be easily reflected on the inclined surface by increasing the incident angle at a location close to or far from the apex of the recess. As a result, the laser beam can be made difficult to pass through the substrate.

  The method for dividing a substrate of the present invention includes a bonding step for bonding the first substrate and the second substrate between the slope forming step and the irradiation step, and the second substrate is a place facing the planned cutting surface. Is characterized in that a structure that is damaged by laser light irradiation is formed.

  According to the method for dividing the substrate, when the laser beam is irradiated onto the planned dividing surface, the structure formed on the second substrate may be irradiated with the laser beam. In the inclined surface forming step, an inclined surface is formed along the planned splitting surface. Therefore, the amount of the laser light that irradiates the structure is reduced by reflecting the laser beam on the inclined surface. As a result, even if the structure is a structure that is damaged by irradiation with laser light, the structure can be hardly damaged.

  In order to solve the above problems, a method for manufacturing an electro-optical device according to the present invention is a method for manufacturing an electro-optical device that is formed by joining a first substrate and a second substrate and then cutting along a planned split surface. A slope forming step of forming a slope on one surface along a planned cutting surface of the first substrate, a bonding step of bonding the first substrate and the second substrate, and a planned cutting surface of the first substrate. And an irradiation step of irradiating a laser beam to form the modified portion, and a dividing step of dividing the first substrate and the second substrate. In the irradiation step, a surface on which the inclined surface is formed; Irradiation is performed so that a part or all of the laser beam is irradiated onto the inclined surface from the opposite surface.

  According to the method for manufacturing the electro-optical device, the laser beam is irradiated in the irradiation step. When the inclined surface is formed so that the incident angle of the laser light reaching the boundary surface between the first substrate and the atmosphere increases from the inside of the first substrate, the amount of laser light reflected by the inclined surface can be increased. . Accordingly, the amount of laser light emitted to the outside of the first substrate is reduced on the planned division surface of the first substrate. As a result, even when there is a structure that is damaged by the laser beam in a location facing the planned splitting surface, the amount of laser light that irradiates this structure is small, so the structure is damaged. Can be difficult.

  In the method of manufacturing the electro-optical device according to the aspect of the invention, in the inclined surface forming step, a concave portion having at least two inclined surfaces is formed along the planned dividing surface of the first substrate, and in the irradiation step, the optical axis of the laser beam is the concave portion. The laser light is irradiated so as to pass through the vicinity of the apex.

  According to the method for manufacturing the electro-optical device, the first substrate is arranged such that at least two inclined surfaces form a concave portion along the planned dividing surface. When the slopes are formed on the right side and the left side of the surface to be divided, the laser light radiated to the right side from the condensing place is easily reflected on the right side slope. Similarly, laser light radiated to the left side from the condensing place is easily reflected by the left slope. That is, both the laser light emitted to the right side from the condensing place and the laser light emitted to the left side are easily reflected in the first substrate by the inclined surface formed in the recess. As a result, it is possible to reduce the amount of laser light that irradiates the location of the second substrate that faces the planned splitting surface.

  The method for manufacturing an electro-optical device according to the present invention is characterized in that an electrode or a wiring is formed on a second substrate at a location facing a predetermined division surface of the first substrate.

  According to the method for manufacturing the electro-optical device, an electrode or a wiring is formed on the second substrate at a location facing the planned dividing surface, and the electrode or the wiring is irradiated with a laser beam in the irradiation process. Is done. Since the electrodes and the wiring are damaged by being irradiated with the laser beam, there is a possibility that the disconnection and part of the electrodes and the wiring may be lost and the resistance value may increase. In the present invention, the light quantity of the laser beam that irradiates the electrode or the wiring can be reduced by forming the inclined surface on the planned dividing surface of the first substrate. As a result, the electrode or the wiring can be hardly damaged by the laser beam.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, each member in each drawing is illustrated with a different scale for each member in order to make the size recognizable on each drawing.

(First embodiment)
In this embodiment, an example in which a laser scribing apparatus is used to scribe and divide by a laser scribing method will be described. Here, before explaining the characteristic manufacturing method of the present invention, a laser scribing apparatus will be described with reference to FIG.

(Laser scribing device)
FIG. 1 is a schematic diagram showing a configuration of a laser scribing apparatus.
As shown in FIG. 1, the laser scribing apparatus 1 includes a laser light source 3 that emits a laser beam 2, an optical path unit 4 that irradiates the workpiece with the emitted laser beam 2, and a workpiece with respect to the optical path unit 4. The table unit 5 that moves relatively and the control device 6 that controls the operation are mainly configured.

The laser light source 3 may be any light source capable of condensing the emitted laser light 2 inside the object to be processed and forming a modified portion by multiphoton absorption. For example, in the present embodiment, the laser light source 3 is composed of a laser medium of LD-excited Nd: YAG (Nd: Y ₃ Al ₅ O ₁₂ ), and is a third harmonic (wavelength: 355 nm) Q-switched pulse oscillation laser. A light emission condition for emitting the light 2 is adopted. The light emission conditions for emitting laser light 2 having a pulse width of approximately 14 ns (nanoseconds), a pulse period of 10 kHz, and an output of approximately 60 μJ / pulse are employed.

  The optical path unit 4 includes a half mirror 7. The half mirror 7 is disposed on the optical axis 2 a of the laser light 2 emitted from the laser light source 3. The half mirror 7 reflects the laser light 2 emitted from the laser light source 3 and changes the traveling direction to the optical axis 2b. A condensing unit 8 is disposed on the optical axis 2b through which the laser beam 2 reflected by the half mirror 7 passes. The condensing part 8 is provided with a condensing lens 8a which is a convex lens in the inside thereof, so that the laser beam 2 can be condensed on the condensing place 2c.

  The condensing unit 8 is supported by the lens moving mechanism 11 by the lens support unit 10. The lens moving mechanism 11 has a linear motion mechanism (not shown), and moves the condensing unit 8 in the direction of the optical axis 2b (Z direction in the drawing) so that the laser light 2 that has passed through the condensing unit 8 is collected. The light location 2c is movable.

  The linear motion mechanism is, for example, a screw type linear motion mechanism provided with a screw shaft (drive shaft) extending in the Z direction and a ball nut screwed to the screw shaft, and the drive shaft receives a predetermined pulse signal. It is connected to a Z-axis motor (not shown) that rotates forward and backward in predetermined step units. When a drive signal corresponding to a predetermined number of steps is input to the Z-axis motor, the Z-axis motor rotates forward or reverse, and the lens moving mechanism 11 corresponds to the number of steps in the direction of the optical axis 2b. It moves forward or backward along.

  An imaging device 12 is provided on an extension line of the optical axis 2 b that passes through the light collector 8 and the half mirror 7, and on the opposite side of the light collector 8 with respect to the half mirror 7. The imaging device 12 includes, for example, a coaxial incident light source and a CCD (Charge Coupled Device) (not shown). Visible light emitted from the coaxial incident light source passes through the condensing unit 8 and irradiates the work 9. The imaging device 12 can image the workpiece 9 through the light collecting unit 8 and the half mirror 7.

  The table unit 5 includes a base 15. On the side of the optical path portion 4 of the base 15, a rail 16 is provided so as to protrude, and an X-axis slide 17 is provided on the rail 16. The X-axis slide 17 includes a linear motion mechanism (not shown) and can move in the X direction on the rail 16. The linear motion mechanism is a mechanism similar to the linear motion mechanism included in the lens moving mechanism 11, and the X-axis slide 17 corresponds to the number of steps corresponding to the drive signal corresponding to the predetermined number of steps in the X direction. It moves forward or backward along.

  A rail 18 is provided so as to protrude from the X-axis slide 17 on the optical path portion 4 side, and a Y-axis slide 19 is provided on the rail 18. The Y-axis slide 19 includes a linear motion mechanism similar to that of the X-axis slide 17 and can move on the rail 18 in the Y direction.

  A stage 20 is disposed on the optical path portion 4 side of the Y-axis slide 19, and a suction chuck mechanism (not shown) is provided on the upper surface of the stage 20. When the workpiece 9 is placed, the workpiece 9 is positioned and fixed at a predetermined position on the upper surface of the stage 20 by the chuck mechanism.

  The control device 6 includes a main computer 24. The main computer 24 includes a CPU (Central Processing Unit) and a memory (not shown). The CPU controls the operation of the laser scribing apparatus 1 according to program software stored in the memory.

  The main computer 24 includes an input / output interface (not shown), and is connected to an input device 25, a display device 26, a laser control device 27, a lens control device 28, an image processing device 29, and a stage control device 30.

  The input device 25 is a device for inputting data of various processing conditions used in laser processing, and the display device 26 is a device for displaying various information at the time of laser processing. The CPU performs laser processing according to various processing conditions and program software that are input, and displays the processing status on the display device 26. The operator looks at various information displayed on the display device 26 and confirms the laser processing status for operation.

  The laser control device 27 is a device that controls the pulse width of the pulse signal that drives the laser light source 3, the pulse period, the start and stop of output, and the like, and is controlled by the control signal of the main computer 24.

  The lens control device 28 is a device that controls the movement and stop of the lens moving mechanism 11. The lens moving mechanism 11 has a built-in position sensor (not shown) that can detect the moving distance, and the lens control device 28 detects the output of the position sensor to detect the position of the light collecting unit 8 in the direction of the optical axis 2b. Recognize position. The lens control device 28 can transmit a pulse signal to the lens moving mechanism 11 to move the lens moving mechanism 11 to a desired position.

  The image processing device 29 has a function of calculating image data output from the imaging device 12. When the work 9 is placed on the stage 20 and an image picked up by the image pickup device 12 is observed, the image is sharpened by operating the lens moving mechanism 11 and changing the distance between the light condensing unit 8 and the work 9. There are times when it is blurred. When the condensing unit 8 is moved to focus on the surface of the work 9 on the stage 20 side and when the work 9 is focused on the surface of the work 9 on the optical path unit 4 side, the captured image becomes clear. On the other hand, when the image is out of focus, the captured image is a blurred image. The image processing device 29 calculates the contrast of the captured image and transmits the contrast data to the main computer 24.

  The main computer 24 moves the condensing unit 8 in the direction of the optical axis 2b, and detects the position of the condensing unit 8 when the image captured by the imaging device 12 becomes clear by using a built-in position sensor. The thickness of the work 9 can be measured.

  By measuring the distance between the in-focus position that is in focus when imaged by the imaging device 12 and the condensing position that is condensed by the condensing unit 8 when the laser beam 2 is irradiated, the in-focus position is measured. It is possible to know the offset distance that is the difference between the position and the light collection position. For example, an object in which two transparent substrates are stacked is placed on the stage 20 as a work 9, and the light condensing unit 8 is moved so that the imaging device 12 is focused on the contact portion between the two substrates. Next, the modified portion is formed by irradiating the laser beam 2. The offset distance can be set by measuring the distance between the contact portion and the reforming portion of the two substrates.

  The condensing unit 8 is moved in the optical axis 2b direction (Z direction in the drawing), and the imaging device 12 is focused on the surface of the work 9 on the optical path unit 4 side. Using the data of the position where the laser beam 2 is desired to be irradiated and the offset distance, the moving distance of the condensing unit 8 is calculated, and the condensing unit 8 is moved by the distance corresponding to the calculated moving distance. With this method, the laser beam 2 can be condensed to a predetermined depth in the workpiece 9.

  The stage control device 30 performs acquisition of position information and movement control of the X-axis slide 17 and the Y-axis slide 19. The X-axis slide 17 and the Y-axis slide 19 have built-in position sensors (not shown), and the stage control device 30 detects the positions of the X-axis slide 17 and the Y-axis slide 19 by detecting the output of the position sensor. To detect. The stage control device 30 acquires the position information of the X-axis slide 17 and the Y-axis slide 19 and compares it with the position information instructed from the main computer 24, and corresponds to the distance corresponding to the difference. And the Y-axis slide 19 are driven to move. The stage control device 30 can drive the X-axis slide 17 and the Y-axis slide 19 to move the workpiece 9 to a desired position.

  The stage control device 30 moves the workpiece 9 in the XY directions, and controls the position where the laser beam 2 is irradiated on the workpiece 9. The image processing device 29 detects the distance between the light collecting unit 8 and the work 9. Based on the detected distance, the lens control device 28 controls the distance between the light condensing unit 8 and the workpiece 9. Subsequently, the laser control device 27 controls the laser light source 3 to emit the laser light 2. The emitted laser beam 2 passes through the optical path section 4 and irradiates the workpiece 9. By performing the above-described control, the laser beam 2 can be condensed and irradiated at a desired position.

  Here, formation of the modified portion by multiphoton absorption will be described. The laser beam 2 condensed by the condensing unit 8 enters the workpiece 9. Even if the workpiece 9 is a material that transmits the laser beam 2, the workpiece 9 absorbs the photon energy when the energy of the photon is much larger than the absorption band gap of the material. This is called multiphoton absorption. When the pulse width of the laser beam 2 is extremely shortened to increase energy and cause multiphoton absorption to occur inside the workpiece 9, the energy of multiphoton absorption is not converted into thermal energy. In addition, a region in which a permanent structural change is induced is formed.

  In the present embodiment, this structure change region is called a modified portion. Of the modified portion, a region where a crack is formed as a result of a large structural change is referred to as a crack portion. Depending on the type of material, for example in the case of quartz glass, a hollow crack may be formed in the crack portion. In addition, the formation of the modified portions by using the laser beam 2 is referred to as laser scribe or scribe.

  The irradiation condition of the laser beam 2 for forming such a modified portion requires setting of the output of the laser beam 2, the pulse width, the pulse period, etc. for each workpiece. In particular, it is necessary to consider that the output of the laser beam 2 irradiated by the laser light source 3 is attenuated by absorption by a transmissive substance arranged on the optical axis 2b such as the half mirror 7 and the light converging unit 8. Therefore, it is desirable to carry out a preliminary test using an actual workpiece to derive optimum irradiation conditions.

(Substrate dividing method)
Next, the substrate cutting method of the present invention will be described with reference to FIGS. FIG. 2 is a flowchart of the substrate dividing method, and FIGS. 3 to 7 are diagrams for explaining the substrate dividing method.

  In the flowchart of FIG. 2, step S <b> 1 corresponds to a slope forming process, which is a process of forming a slope at a place where the substrate is to be laser scribed. Next, the process proceeds to step S2. Step S2 corresponds to a bonding step, and is a step of bonding two substrates by applying an adhesive to the substrates. Next, the process proceeds to step S3. Step S <b> 3 corresponds to a moving process, and is a process of moving a place where laser light is to be irradiated to a place facing the light collecting unit 8. Next, the process proceeds to step S4. Step S4 corresponds to an irradiation step, and is a step of forming a modified portion by irradiating the substrate with laser light. Next, the process proceeds to step S5.

  Step S5 corresponds to the step of determining whether or not the reforming part has been formed in all the planned areas, and the area where the reforming part is to be formed is compared with the area where the reforming part is formed. This is a step of searching for a region to be formed in which a modified portion has not yet been formed. When there is a region in which the reforming portion is not formed yet in the region where the reforming portion is to be formed (NO), the process proceeds to step S3. When there is no region where the modified portion is not formed in the region where the modified portion is to be formed (YES), the process proceeds to step S6. Step S3 to step S5 are combined to form a laser scribing step of step S11.

  Step S6 corresponds to a dividing step, and is a step of dividing the substrate by pressing the place where the modified portions of the substrate are arranged and formed. The process of dividing the substrate is completed by the above steps.

  Next, the manufacturing method will be described in detail with reference to FIGS. 1 and 3 to 7 in association with the steps shown in FIG. FIG. 3A is a schematic plan view of a substrate formed in the present embodiment, and FIG. 3B is a schematic side view of the substrate viewed from the Y direction. As shown in FIGS. 3A and 3B, the substrate 33 has a first substrate 34 formed in a rectangular shape and a second substrate 35 also formed in a rectangular shape, which are bonded by an adhesive 36. . And after the edge part 34a of the 1st board | substrate 34 is parted by the parting plan surface 34b, it is removed. The first substrate 34 and the second substrate 35 are made of a material that is transmissive to the laser light 2. In the present embodiment, for example, quartz glass is used. A wiring 37 as a structure is formed on the surface of the second substrate 35 facing the first substrate 34, and the wiring 37 is made of metal. For this reason, when the wiring 37 is irradiated with the laser beam 2, there is a risk that the wiring 37 may be damaged and disconnected, or a part of the wiring 37 may be lost, resulting in an increase in electrical resistance.

  FIGS. 3C to 4A are diagrams corresponding to step S <b> 1, in which the first substrate 34 is viewed from the side. FIG. 3C and FIG. 4A are schematic side views of the substrate viewed from the Y direction, and FIG. 3D is a schematic side view of the substrate viewed from the X direction. As shown in FIG. 3C and FIG. 3D, the first substrate 34 is moved along the planned cutting surface 34 b of the first substrate 34 while contacting the rotating grindstone 38. Grind. Since the outer periphery of the grindstone 38 is formed in a V shape, a V-shaped recess 39 is formed on the first substrate 34 in substantially the same shape as the outer periphery of the grindstone 38. Subsequently, polishing is performed using a polishing disk that rotates the recess 39 while flowing the polishing liquid into the recess 39. The grinding method and the polishing method using the grindstone 38 are known techniques, and detailed description of processing conditions and the like is omitted. As a result, as shown in FIG. 4A, the first substrate 34 in which the V-shaped recess 39 is formed is completed.

  4B and 4C are diagrams corresponding to step S2, and are schematic side views of the substrate as viewed from the Y direction. As shown in FIG. 4B, an adhesive 36 is applied to the second substrate 35 on which the wiring 37 is formed. At this time, the adhesive 36 is applied to a place where the first substrate 34 and the second substrate 35 are to be bonded. Then, the first substrate 34 and the second substrate 35 are bonded together by aligning the surface of the first substrate 34 where the recess 39 is formed and the surface of the second substrate 35 where the adhesive 36 is applied.

  As a result, as shown in FIG. 4C, the first substrate 34 and the second substrate 35 are bonded to each other. Next, by drying the substrate 33 by heating, the adhesive 36 is solidified, and the joining of the first substrate 34 and the second substrate 35 is completed.

  FIG. 5A and FIG. 5B are diagrams corresponding to step S3. FIG. 5A is a schematic side view of the substrate viewed from the Y direction, and FIG. 5B is a schematic side view of the substrate viewed from the direction opposite to the X direction. As shown in FIGS. 5 (a) and 5 (b), by moving the stage 20, the place of the planned point 40, which is the place where the reforming part is to be formed, is placed in a place facing the light collecting part 8. The substrate 33 is moved so that is positioned.

  The scheduled point 40 is set on the planned dividing surface 34 b at a location near the second substrate 35 and a location near the end surface 34 e of the first substrate 34.

  FIG.5 (c)-FIG.7 (b) are figures corresponding to step S4. FIG. 5C is a side view of the substrate viewed from the Y direction. As shown in FIG. 5C, the condensing unit 8 condenses the laser light 2 and irradiates the inside of the first substrate 34. A reforming portion 41 is formed at a condensing place 2 c where the laser beam 2 is collected and irradiated, and a hollow crack portion 42 is formed at the center of the reforming portion 41.

  FIG. 6 is a partial cross-sectional view of the vicinity of the recess 39 when irradiated with the laser beam 2 as seen from the Y direction. As shown in FIG. 6, the laser beam 2 is irradiated so that the optical axis 2b passes through substantially the same place as the planned splitting surface 34b. Then, the laser beam 2 is condensed at the condensing place 2 c by the condensing unit 8. A light beam 2d to a light beam 2i indicate the laser light 2 collected at the light condensing place 2c. The apex 39a of the recess 39 formed on the first substrate 34 is disposed on the planned splitting surface 34b.

  The light rays 2d to 2f irradiated from the upper left in the drawing to the light condensing place 2c travel to the inside of the first substrate 34 by irradiating the right inclined surface 39b and then reflecting on the inclined surface 39b. Then, the light rays 2d to 2f are reflected by the surface 34c of the first substrate 34 facing the second substrate 35, and proceed to the inside. At this time, since the refractive index of the first substrate 34 is larger than that of the atmosphere, the laser light 2 traveling from the first substrate 34 to the atmosphere is easily reflected.

  Similarly, the light rays 2g to 2i irradiated from the upper right in the drawing to the light condensing place 2c travel to the inside of the first substrate 34 by irradiating the left inclined surface 39c and then reflecting on the inclined surface 39c. To do. Then, the light rays 2g to 2i are reflected by the surface 34c of the first substrate 34 facing the second substrate 35 and proceed to the inside. Therefore, it is difficult for the laser beam 2 to pass along the scheduled splitting surface 34b.

  In step S <b> 5, the main computer 24 compares the irradiation planned position stored in the memory with the irradiated position, and searches for an unirradiated place. Then, by repeating Steps S3 to S5, first-stage reforming portions 41a are first arranged and formed as shown in FIG. 7A. Then, the condensing place 2c which condenses and irradiates the laser beam 2 is moved in the thickness direction of the first substrate 34, and the processing is continued. Then, the reforming parts 41 are arranged at a location adjacent to the reforming part 41 formed in the first stage 41a to form the second stage reforming part 41. The third and subsequent stages are formed in the same manner.

  As a result, as shown in FIG. 7B, a scribe surface 34 d in which the modified portions 41 are arranged and formed is formed along the planned division surface 34 b of the first substrate 34.

  FIG.7 (c)-FIG.7 (d) are figures corresponding to step S6, and are the model side views which looked at the board | substrate from the Y direction. As shown in FIG. 7C, the substrate 33 is placed on at least a base 43 made of an elastic material or the like. The place facing the scribe surface 34d formed on the planned cutting surface 34b is pressed using the pressing member 44. The substrate 33 sinks into the base 43 and a tension acts on the crack portion 42. The first substrate 34 breaks and breaks starting from the crack portion 42a close to the surface in contact with the base 43.

  As a result, as shown in FIG. 7D, the first substrate 34 is divided by the scribe surface 34d, and the substrate 33 shown in FIG. 3A is completed.

As described above, this embodiment has the following effects.
(1) According to the present embodiment, as shown in FIG. 6, when the inclined surfaces 39b and 39c are formed so that the incident angle 45 of the laser beam 2 traveling from the first substrate 34 to the atmosphere increases, The amount of the laser beam 2 reflected by 39b and 39c can be increased. Therefore, the light quantity of the laser beam 2 emitted to the outside of the first substrate 34 decreases from the condensing place 2c of the first substrate 34 along the planned division surface 34b. As a result, even when there is a wiring 37 that is damaged by the laser light 2 at a location facing the planned splitting surface 34b, the amount of the laser light 2 that irradiates the wiring 37 is small. It can be made less susceptible to damage.

  (2) According to the present embodiment, the two inclined surfaces 39b and 39c are arranged on the first substrate 34 so as to form the recesses 39 with the scheduled division surface 34b as the center. And the laser beam 2 radiated | emitted from the condensing location 2c is radiated | emitted in the direction which leaves | separates from the parting plan surface 34b. Thereafter, the laser beam emitted to the right side and the laser beam emitted to the left side from the condensing place 2c are reflected into the first substrate 34 by the inclined surfaces 39b and 39c. As a result, it is possible to reduce the light amount of the laser light 2 that irradiates the place facing the planned splitting surface 34b.

(Second Embodiment)
Next, an embodiment of a substrate cutting method embodying the present invention will be described with reference to FIG. FIG. 8 is a diagram for explaining a method for dividing the substrate, and is a partial cross-sectional view of the vicinity of the recess when the laser beam is irradiated as viewed from the Y direction.
This embodiment is different from the first embodiment in that the shape of the recess formed in the first substrate is different.

  As shown in FIG. 8, the recess 48 formed in the first substrate 47 corresponding to the first substrate 34 in the first embodiment has the apex 48a disposed on the planned splitting surface 47a, and the splitting target surface 47a as the center. As shown in FIG. 4, the right slope 48b and the left slope 48c are used. The inclined surface 48b and the inclined surface 48c are formed by flat surfaces in the first embodiment, but are formed by curved surfaces in this embodiment. The slope 48d at a location close to the apex 48a is formed at an acute angle compared to the slope 48e at a location far from the apex 48a.

  Of the laser beam 2 radiated from the condensing place 2 c, the light beam 2 f traveling at an acute angle with respect to the optical axis 2 b irradiates the inclined surface 48 d near the vertex 48 a of the recess 48. At this time, since the inclined surface 48d close to the apex 48a of the recess 48 is formed at an acute angle with respect to the optical axis 2b, the incident angle 45d of the laser light 2 that irradiates the inclined surface 48d increases at the inclined surface 48d, It is easy to reflect.

  Of the laser light 2 emitted from the condensing place 2c, the light beam 2d traveling at an angle larger than the light beam 2f with respect to the optical axis 2b irradiates the inclined surface 48e far from the apex 48a of the recess 48. At this time, the inclined surface 48e far from the apex 48a of the recess 48 is formed at an angle larger than the inclined surface 48d with respect to the optical axis 2b, but the laser beam 2 irradiating the inclined surface 48e at this location is applied to the optical axis 2b. Since the laser beam 2 irradiates the inclined surface 48e, the incident angle 45e is increased on the inclined surface 48e and is easily reflected.

  Since the inclined surface 48c is formed in a substantially target shape with the inclined surface 48b with respect to the planned cutting surface 47a, the light ray 2g travels in the same manner as the light ray 2f. The light ray 2i travels in the same manner as the light ray 2d.

As described above, according to the present embodiment, in addition to the effects (1) and (2) in the first embodiment, the following effects are obtained.
(1) According to the present embodiment, the incident angle 45 becomes large on the inclined surface 48d near the vertex 48a of the concave portion 48 and on the inclined surface 48e far from the vertex 48a of the concave portion 48, and the laser beam 2 is reflected by the inclined surface 48b. Since it becomes easy, it can make it difficult to pass a board | substrate.

(Third embodiment)
Next, an embodiment of a method for manufacturing a liquid crystal display device embodying the present invention will be described with reference to FIGS.
In this embodiment, an example in the case of manufacturing a liquid crystal display device using the substrate cutting method according to the present invention will be described. Here, before describing the characteristic manufacturing method of the present invention, a liquid crystal display device will be described.

(Liquid crystal display device)
FIG. 9A is a schematic plan view of the liquid crystal display device, and FIG. 9B is a schematic cross-sectional view taken along the line AA ′ of the liquid crystal display device of FIG. 9A.

  9A and 9B, a liquid crystal display device 51 as an electro-optical device according to the present embodiment includes a pair of TFT array substrate 52 (Thin Film Transistor) and a counter substrate 53 that are thermosetting. A liquid crystal layer made of liquid crystal 55 is sandwiched between regions bonded by a seal 54 as a sealing material and enclosed in a region partitioned by the seal 54. The seal 54 is formed in a frame shape closed in a region within the substrate surface.

  A peripheral parting 56 for concealing the wiring with a light shielding material is formed on the liquid crystal 55 side surface of the counter substrate 53 inside the place where the seal 54 is formed. A data line driving circuit 57 and a mounting terminal 58 as an electrode are formed along the side 52a (the lower side in FIG. 9A) of the TFT array substrate 52 at a location outside the seal 54. A scanning line driving circuit 59 is formed along the side 52b and the side 52c (left and right sides in FIG. 9A) adjacent to 52a. The data line driving circuit 57, the mounting terminal 58, and the scanning line driving circuit 59 are electrically connected by a wiring 60a made of aluminum. On the remaining side 52d (the upper side in FIG. 9A) of the TFT array substrate 52, a wiring 60b for connecting the two scanning line driving circuits 59 is provided. In addition, inter-substrate conductive members 61 for providing electrical continuity between the TFT array substrate 52 and the counter substrate 53 are disposed at the four corners of the counter substrate 53.

  The liquid crystal display device 51 is configured for color display. On the counter substrate 53, red (R), green (G), and blue (B) color filters 62R, 62G, and 62B are formed together with a protective film (not shown). Has been. A light shielding film 63 is formed between the filter elements of the color filters 62R, 62G, and 62B, and the light shielding film 63 blocks light that does not pass through the color filters 62R, 62G, and 62B. Further, a counter electrode 64 and an alignment film 65 are arranged on the TFT array substrate 52 side of the color filters 62R, 62G, and 62B.

  The liquid crystal has the property that the tilt angle of the liquid crystal changes when a voltage is applied to the electrodes sandwiching the liquid crystal, and the switching angle of the TFT controls the tilt angle of the liquid crystal by controlling the voltage applied to the liquid crystal. Every time the light is transmitted or blocked. Thereby, the transmitted light passes through a color filter having three color filters of red (R), green (G), and blue (B) that are installed relative to each pixel. The color of each corresponding color filter is transmitted as colored light. In addition, since light does not naturally enter the color filter corresponding to the pixel where the light is blocked by the liquid crystal, the color filter is black. In this way, by switching the TFT, the liquid crystal is operated as a shutter, the transmission of light is controlled for each pixel, and the pixel is blinked, so that a color image can be displayed.

  In the region for displaying an image of the liquid crystal display device 51 having such a structure, a plurality of pixels are configured in a matrix of m rows and n columns, and a pixel signal is switched to each of these pixels. A TFT (switching element) is formed. A data line (source wiring) for supplying a pixel signal is electrically connected to the source electrode of the TFT, a scanning line (gate wiring) for supplying a scanning signal is electrically connected to the gate electrode of the TFT, and a drain electrode of the TFT A pixel electrode 66 is electrically connected to the first electrode. The pixel electrode 66 is formed at a location facing each filter element of the color filters 62R, 62G, and 62B. A scanning signal of a pulse signal is supplied from the scanning line to the gate electrode of the TFT to which the scanning line is connected at a predetermined timing.

  The pixel electrode 66 is electrically connected to the drain of the TFT, and the pixel signal supplied from the data line is applied to the pixel electrode 66 of each pixel by turning on the TFT as a switching element for a certain period. It is supplied at the timing. The voltage level of the pixel signal of the predetermined level supplied to the pixel electrode 66 in this way is held between the counter electrode 64 of the counter substrate 53, and the light transmission amount of the liquid crystal 55 according to the voltage level of the pixel signal. Changes. The liquid crystal display device 51 includes a color filter, and the liquid crystal display device 51 is controlled by controlling the light transmitted through the color filters 62R, 62G, and 62B by an image signal applied to an electrode that sandwiches a liquid crystal layer made of liquid crystal 55. A color image can be displayed.

  An alignment film 67 is disposed on the counter substrate 53 side of the pixel electrode 66. The alignment film 65 and the alignment film 67 have groove-like irregularities formed on the surfaces thereof, and the liquid crystal 55 filled between the alignment film 65 and the alignment film 67 is arranged along the groove-like irregularities. Formed.

  In the TFT array substrate 52 and the counter substrate 53, a polarizing sheet (not shown) is disposed on the surface opposite to the liquid crystal 55, and the amount of light transmitted through the liquid crystal display device 51 is changed by the action of the polarizing sheet and the liquid crystal 55. It is like that.

(Manufacturing method of liquid crystal display device)
Next, a method for dividing the substrate in the above-described liquid crystal display device 51 will be described with reference to FIGS. FIG. 10 is a flowchart of the substrate dividing method, and FIGS. 11 to 14 are diagrams for explaining the substrate dividing method.

  In the flowchart of FIG. 10, step S <b> 21 corresponds to an inclined surface forming process, and is a process of forming a concave portion having an inclined surface along the planned dividing surface of the counter mother substrate. Step S22 corresponds to an element formation step, and is a step of forming elements for driving the liquid crystal, wiring, electrodes, and the like. Next, the process proceeds to step S23. Step S23 corresponds to a bonding step, and is a step of bonding the element mother substrate and the counter mother substrate. Next, the process proceeds to step S24.

  Step S24 corresponds to a first scribing process of the counter mother substrate, and is a process of scribing by irradiating the counter mother substrate with laser light and arranging and forming the modified portions in one direction. Next, the process proceeds to step S25. Step S25 corresponds to the second scribing step of the counter mother substrate, and the counter mother substrate is irradiated with laser light, and the modification parts are arranged in a direction orthogonal to the scribed direction to form a scribe. It is a process. Next, the process proceeds to step S26. Step S26 corresponds to a first scribing process of the element mother substrate, and is a process of scribing by irradiating the element mother substrate with laser light and arranging and forming the modified portions in one direction. Next, the process proceeds to step S27. Step S27 corresponds to a second scribing step for the element mother substrate. By irradiating the element mother substrate with a laser beam, the modified portions are arranged in a direction perpendicular to the direction scribed in step S26. , Scribe process. Next, the process proceeds to step S28.

  Step S28 corresponds to a first parting process of the element mother substrate, and is a part of cutting the place scribed in step S26. Next, the process proceeds to step S29. Step S29 corresponds to a second parting step of the element mother substrate, and is a step of cutting the place scribed in step S27. Next, the process proceeds to step S30. Step S30 corresponds to a first dividing step of the counter mother substrate, and is a step of dividing the place scribed in step S24. Next, the process proceeds to step S31. Step S31 corresponds to a second dividing step of the counter mother substrate, and is a step of dividing the place scribed in step S25.

  Step S24 to step S27 are collectively referred to as step S41. Step S41 corresponds to a laser scribing process, and is a process of scribing by irradiating the counter substrate 53 and the TFT array substrate 52 with the laser beam 2 and arranging and forming the modified portions. And step S28-step S31 are put together and it is set as step S42. Step S42 corresponds to a dividing step, and is a step of dividing the counter mother substrate and the element mother substrate. Through the above steps, the liquid crystal display device 51 is formed.

Next, the manufacturing method will be described in detail with reference to FIGS. 11 to 14 in association with the steps shown in FIG.
FIG. 11A and FIG. 11B are diagrams corresponding to step S21. FIG. 11A is a schematic plan view showing a counter mother substrate that is a mother substrate in which the counter substrate is partitioned. FIG.11 (b) is a schematic cross section along the BB 'line of Fig.11 (a).

  As shown in FIGS. 11A and 11B, the counter mother substrate 71 is configured by a substrate 72 as a first substrate formed in a disc shape. The material of the board | substrate 72 should just be a material with a light transmittance, for example, quartz glass is employ | adopted in this embodiment.

  Of the surfaces that are to be divided in order to cut out the liquid crystal display device 51 from the counter mother substrate 71, a surface that is to be cut in the X-axis direction is referred to as an H counter cutting surface 73. The H facing cut surface 73 is a cut surface of the substrate 72 indicated by a one-dot chain line, and is a cut surface extending in the X-axis direction. 73a, 73b, 73c, 73d and 73e are H-opposing cut surfaces 73, respectively.

  Similarly, a surface that is to be cut in the Y-axis direction among the surfaces that are to be divided to cut out the liquid crystal display device 51 from the counter mother substrate 71 is referred to as a V-facing cutting surface 74. The V facing cut surface 74 is a cut surface of the substrate 72 indicated by a one-dot chain line, and is a cut surface extending in the Y-axis direction. 74a, 74b, and 74c are V-opposing cut surfaces 74, respectively.

  The substrate 72 is ground by advancing while the rotating grindstone 38 is in contact with the substrate 72 along the H facing cut surface 73 a of the substrate 72. Since the outer periphery of the grindstone 38 is formed in a V shape, a V-shaped recess 39 is formed on the substrate 72 in substantially the same shape as the outer periphery of the grindstone 38. Similarly, the concave portion 39 is formed along the other H-opposing cutting plane 73 and V-opposing cutting plane 74.

  FIG. 12A and FIG. 12B are diagrams corresponding to step S22. FIG. 12A is a schematic cross-sectional view showing the counter mother substrate, and FIG. 12B is a schematic cross-sectional view showing the element mother substrate. As shown in FIG. 12A, a peripheral parting 56, a color filter 62, and a light shielding film 63 are formed on the substrate 72 in the counter mother substrate 71. Further, on the surfaces of the peripheral parting 56, the color filter 62, and the light shielding film 63, a light transmissive and conductive counter electrode 64 is formed. After the alignment film 65 is formed on the surface of the counter electrode 64, an alignment process for forming irregularities on the surface is performed.

  As shown in FIG. 12B, in the element mother substrate 75, a pixel electrode 66 and a TFT for switching the pixel electrode 66 are formed on a substrate 76 as a second substrate formed in a disc shape. Thereafter, an alignment film 67 is formed on the surface of the pixel electrode 66. Then, the alignment film 67 is subjected to an alignment process. Next, wirings 60a and 60b and mounting terminals 58 are formed. Thereafter, the data line driving circuit 57 and the scanning line driving circuit 59 shown in FIG. 9 are mounted. Since the manufacturing method in step S22 is manufactured by a well-known technique, detailed description is abbreviate | omitted.

  FIG. 13A and FIG. 13B are diagrams corresponding to step S23. FIG. 13A is a schematic plan view showing the counter mother substrate, and FIG. 13B is a schematic cross-sectional view taken along the line C-C ′ of FIG. As shown in FIGS. 13A and 13B, a sealing material 54a, which is a material of the seal 54, is applied on the substrate 76 in a frame shape. The method of applying the sealing material 54a only needs to apply the seal 54 in a desired shape. For example, in this embodiment, a screen printing method is adopted. The sealing material 54a may be any material that can obtain an adhesive force after solidification and does not deteriorate due to contact with the liquid crystal 55. For example, in the present embodiment, a thermosetting epoxy resin is used.

  After the sealing material 54a is applied in a frame shape, the liquid crystal 55 is applied inside the sealing material 54a using a dispenser. The element mother substrate 75 is placed in a vacuum chamber (not shown), and the inside of the vacuum chamber is evacuated to make a vacuum. In a vacuum, the opposing mother substrate 71 and the element mother substrate 75 are pressed together with their relative positions.

  A seal material 54 a is applied to one element mother substrate 75 in a shape corresponding to the plurality of liquid crystal display devices 51, and one counter mother substrate 71 is disposed on one element mother substrate 75. After the opposing mother substrate 71 is pressed against the element mother substrate 75, air flows into the vacuum chamber. Therefore, the opposing mother substrate 71 and the element mother substrate 75 are pressurized by atmospheric pressure.

  Heating is performed while maintaining the relative position between the opposing mother substrate 71 and the element mother substrate 75, and the seal material 54a is solidified to form the seal 54. The mother substrate 77 in which the counter mother substrate 71 and the element mother substrate 75 are bonded via the seal 54 is completed, and Step S23 is completed. Since the manufacturing method in step S23 is manufactured by a well-known technique, detailed description is abbreviate | omitted.

  Of the surfaces that are to be divided to cut out the liquid crystal display device 51 from the element mother substrate 75, the surface that is to be cut in the X-axis direction is referred to as an H element cutting surface 78. The H element cut surface 78 is a cut surface of the substrate 76 indicated by a one-dot chain line, and is a cut surface extending in the X-axis direction. Reference numerals 78a, 78b, and 78c denote H element cut surfaces 78, respectively.

  Similarly, a surface scheduled to be cut in the Y-axis direction among surfaces scheduled to be cut out to cut out the liquid crystal display device 51 from the element mother substrate 75 is referred to as a V element cutting surface 79. The V element cut surface 79 is a cut surface of the substrate 76 indicated by a one-dot chain line, and is a cut surface extending in the Y-axis direction. 79a, 79b and 79c are V element cut surfaces 79, respectively. 74d, 74e, and 74f extending in the Y-axis direction of the counter mother substrate 71 are V-opposing cut surfaces 74, respectively.

  14A and 14B are diagrams corresponding to step S24, and are schematic cross-sectional views viewed from the X direction. As shown in FIG. 14A, the laser beam 2 is condensed and irradiated inside the substrate 72 using the condensing unit 8. A reforming portion 41 is formed at a location where the laser beam 2 is condensed, and a crack portion 42 is formed at the center of the reforming portion 41.

  While the condensing unit 8 and the counter mother substrate 71 are moved relatively, the laser beam 2 is irradiated and the reforming units 41 are arranged and formed. At this time, since the laser beam 2 is reflected by the recess 39, the amount of the laser beam 2 that irradiates the element mother substrate 75 after the laser beam 2 passes through the substrate 72 is reduced.

  The light collector 8 and the counter mother substrate 71 are relatively moved along the V counter cut surface 74 in the planar direction of the counter mother substrate 71. Subsequently, the place where the laser beam 2 is condensed is moved in the thickness direction of the substrate 72. After the movement, the laser beam 2 is irradiated while moving the condensing part 8 and the counter mother substrate 71 relatively, and the reforming parts 41 are arranged and formed. This process is repeated to form the crack surfaces 80 formed by arranging the modified portions 41 on all the V opposing cut surfaces 74 of the opposing mother substrate 71.

  As a result, as shown in FIG. 14B, crack surfaces 80 are formed in which the modified portions 41 are arranged on all the V opposing cut surfaces 74 of the opposing mother substrate 71.

  In step S25, the laser beam 2 is irradiated along the H-opposing cut surface 73 of the opposed mother substrate 71 shown in FIG. As a result, similarly to step S <b> 24, crack surfaces 80 are formed in which the reforming portions 41 are arranged on all the H opposing cut surfaces 73 of the opposing mother substrate 71. At this time, the laser beam 2 is reflected by the recess 39, so that after the laser beam 2 passes through the substrate 72, the amount of the laser beam 2 that irradiates the element mother substrate 75 becomes small.

  In step S <b> 26, the mother substrate 77 is inverted and the laser light 2 is irradiated along the H element cutting surface 78 of the element mother substrate 75. As a result, as in step S <b> 24, crack surfaces 80 are formed in which the modified portions 41 are formed on all the H element cut surfaces 78 of the element mother substrate 75.

  In step S <b> 27, the laser beam 2 is irradiated along the V element cutting surface 79 of the element mother substrate 75. As a result, as in step S24, crack surfaces 80 are formed in which the modified portions 41 are arranged on all the V element cut surfaces 79 in the element mother substrate 75.

  14C and 14D are diagrams corresponding to step S28, and are schematic cross-sectional views viewed from the X direction. As shown in FIG. 14 (c), the element mother substrate 75 is arranged on the base 43 made of an elastic material, and the place facing the crack surface 80 of the H element cutting surface 78 is pressed using the pressure member 44. To do. The element mother substrate 75 sinks into the base 43 and a tension acts on the crack portion 42. The element mother substrate 75 breaks and breaks starting from the crack portion 42b close to the surface in contact with the base 43.

  As a result, as shown in FIG. 14D, the element mother substrate 75 is divided at the crack surfaces 80 of all the H element cut surfaces 78 formed on the element mother substrate 75.

  In step S29, as in step S28, the element mother substrate 75 is placed on the base 43 made of an elastic material, and the place facing the crack surface 80 of the V element cutting surface 79 is pressed using the pressure member 44. To do. The element mother substrate 75 breaks and breaks starting from the crack portion 42b close to the surface in contact with the base 43. As a result, the element mother substrate 75 is divided at the crack surfaces 80 of all V element cut surfaces 79 formed on the element mother substrate 75.

  In step S30, the mother substrate 77 is inverted, the opposing mother substrate 71 is placed on the base 43 made of an elastic material, and the pressure member 44 is used at a location facing the crack surface 80 of the H opposing cutting surface 73. Press. The opposing mother substrate 71 breaks up and breaks starting from the crack portion 42b close to the surface in contact with the base 43. As a result, in the opposing mother substrate 71, the crack surfaces 80 of all the H opposing cutting surfaces 73 formed on the opposing mother substrate 71 are divided.

  In step S <b> 31, the opposing mother substrate 71 is placed on the base 43 made of an elastic material, and the place facing the crack surface 80 of the V opposing cutting surface 74 is pressed using the pressing member 44. The opposing mother substrate 71 breaks up and breaks starting from the crack portion 42b close to the surface in contact with the base 43. As a result, in the opposing mother substrate 71, the crack surfaces 80 of all the V opposing cutting surfaces 74 formed on the opposing mother substrate 71 are divided, and a plurality of liquid crystal display devices 51 are formed from the mother substrate 77.

  A liquid crystal display device 51 is completed by attaching a polarizing sheet (not shown) to the TFT array substrate 52 and the counter substrate 53 shown in FIG.

As described above, this embodiment has the following effects.
(1) According to this embodiment, in the element mother substrate 75, the wirings 60a and 60b are formed at locations facing the H-opposing cut surface 73, and the wirings 60a and 60b include step S24 and step In S25, the laser beam 2 is irradiated. By forming a V-shaped recess 39 including a slope on the H-facing cutting surface 73 and the V-facing cutting surface 74 of the facing mother substrate 71, the laser beam 2 is reflected by the slope, so that the wires 60a and 60b are irradiated. The amount of laser light to be reduced can be reduced. As a result, the wirings 60a and 60b can be hardly damaged by the laser beam 2.

  (2) According to the present embodiment, the substrate 72 is arranged such that two slopes on the left and right sides form recesses along the H facing cutting surface 73 and the V facing cutting surface 74. The laser light 2 radiated to the right side from the condensing place 2c of the laser light 2 and the laser light 2 radiated to the left side are easily reflected in the board 72 plate by the inclined surface formed in the recess. As a result, it is possible to reduce the light amount of the laser light 2 that irradiates a place facing the H-opposing cut surface 73 and the V-opposing cut surface 74.

In addition, this invention is not limited to embodiment mentioned above, A various change and improvement can also be added. A modification will be described below.
(Modification 1)
In the first embodiment, as shown in FIG. 6, the recess 39 is formed in a V shape. However, as shown in FIG. 15, the recess 81 may be formed in a trapezoidal shape. The light rays 2g to 2i traveling from the upper right to the lower left with respect to the light condensing place 2c are reflected by the inclined surface 81c and travel to the left side inside the first substrate 34. Since the light rays 2d to 2f traveling from the upper left to the lower right with respect to the light condensing place 2c pass through the upper surface 81a, the amount of light traveling to the lower side of the first substrate 34 is the first embodiment. Compared to

  Since the recess 81 has a flat top surface 81a, the tip of the grindstone forming the recess 81 can be made flat. Compared to the case where the tip of the grindstone is protruding, the pressure applied to the tip of the grindstone is smaller when the tip is flat, so that wear at the tip is reduced. As a result, the service life of the grindstone is extended and a resource-saving processing method can be achieved.

(Modification 2)
In the third embodiment, the wirings 60a and 60b are formed at locations facing the H-facing cutting surface 73 and the V-facing cutting surface 74, but in addition to the wiring, electrodes, a data line driving circuit 57, and a scanning line driving circuit. An element such as 59 may be used. Since the amount of the irradiated laser beam 2 is small, it can be made difficult to be damaged.

(Modification 3)
In the third embodiment, quartz glass is used for the counter substrate 53, but the present invention is not limited to this. Any brittle material that has optical transparency and can constitute the liquid crystal display device 51 may be used. For example, in addition to quartz glass, borosilicate glass such as soda lime glass and Pyrex (registered trademark), OA-10 (Nippon Electric Glass) Non-alkali glass such as Neoceram (registered trademark), optical glass, crystal and the like. Even in this case, the same effects as those of the embodiment can be obtained.

  Similarly, in the first embodiment, quartz glass is used for the first substrate 34, but the present invention is not limited to this. Any light-transmitting brittle material may be used. For example, in addition to quartz glass, soda-lime glass, borosilicate glass such as Pyrex (registered trademark), alkali-free glass such as OA-10 (manufactured by Nippon Electric Glass), Examples thereof include heat-resistant crystallized glass such as Neoceram (registered trademark), optical glass, and crystal. Even in this case, the same effects as those of the embodiment can be obtained.

(Modification 4)
In the above embodiment, the manufacturing method of the present invention is used for the liquid crystal display device 51, but it can also be used for electro-optical devices other than the liquid crystal display device 51. As an electro-optical device provided with a substrate, for example, it can be suitably used as a manufacturing method in a plasma display, an organic EL (Electro Luminescence) display, a vacuum fluorescent display, a field emission display, and the like. In any case, the same effects as those of the embodiment can be obtained.

(Modification 5)
In the above embodiment, a YAG laser is used for the laser light source 3, but a femtosecond laser may be used. Any light source may be used as long as the emitted laser light is condensed inside the object to be processed to form a modified portion by multiphoton absorption. For example, a so-called femtosecond laser that emits laser light using titanium sapphire as a solid light source with a pulse width of femtosecond may be employed. As an example of the light emission conditions and the condensing lens conditions, the pulsed laser light has wavelength dispersion characteristics, the center wavelength is 800 nm, and the half width is about 20 nm. The pulse width is about 300 fs (femtosecond), the pulse period is 1 kHz, and the output is about 700 mW. In this case, the condenser lens may be an objective lens having a magnification of 100, a numerical aperture (NA) of 0.8, and a WD (Working Distance) of 3 mm. The same effect as when using a YAG laser can be obtained.

(Modification 6)
In the second embodiment, the slopes 48b and 48c of the recess 48 shown in FIG. 8 are formed as curved surfaces, but they may be composed of a plurality of planes. When forming a grindstone, the angle of the planes 48b and 48c can be formed with high accuracy because the plane is easier to form with higher accuracy than the curved surface.

Schematic which shows the structure of the laser scribing apparatus which concerns on 1st Embodiment. The flowchart of the dividing method of a board | substrate. The figure explaining the division | segmentation method of a board | substrate. The figure explaining the division | segmentation method of a board | substrate. The figure explaining the division | segmentation method of a board | substrate. The figure explaining the division | segmentation method of a board | substrate. The figure explaining the division | segmentation method of a board | substrate. The figure explaining the division | segmentation method of the board | substrate which concerns on 2nd Embodiment. The schematic diagram of the liquid crystal display device which concerns on 3rd Embodiment. 6 is a flowchart of a substrate dividing method in a liquid crystal display device. 4A and 4B illustrate a method for dividing a substrate in a liquid crystal display device. 4A and 4B illustrate a method for dividing a substrate in a liquid crystal display device. The schematic diagram which shows the mother board | substrate with which the liquid crystal display panel was dividedly formed. 4A and 4B illustrate a method for dividing a substrate in a liquid crystal display device. The figure explaining the division | segmentation method of the board | substrate concerning the modification 1. FIG.

Explanation of symbols

  2 ... Laser beam 34b ... Scheduled surface 34 ... First substrate 35 ... Second substrate 37 ... Wiring as a structure 39, 48, 81 ... Recess, 39a ... Vertex 39b, 39c, 48b, 48c , 48d, 48e... Slope, 41... Reforming section, 47... First substrate, 51... Liquid crystal display device as an electro-optical device, 72.

Claims (7)

A substrate cutting method for cutting a first substrate along a planned cutting surface,
A slope forming step of forming a slope on one surface along the planned cutting surface of the first substrate;
An irradiation step of irradiating a laser beam along the planned cutting surface of the first substrate to form a modified portion;
A cutting step of applying stress to the modified portion and cutting the first substrate;
In the irradiation step, the substrate is divided by irradiating the inclined surface with a part or all of the laser beam from a surface opposite to the surface on which the inclined surface is formed. A method for dividing a substrate according to claim 1,
In the slope forming step, a concave portion having at least two slopes is formed along the planned splitting surface of the first substrate,
In the irradiation step, the laser beam is irradiated so that the optical axis of the laser beam passes near the apex of the recess.   The method for dividing a substrate according to claim 2, wherein, in at least one of the inclined surfaces, the inclined surface formed at an angle between the inclined surface and the planned dividing surface is close to the apex of the recess. A method for dividing a substrate, wherein the substrate is formed at an acute angle compared to the inclined surface at a position far from the apex of the recess. A method for dividing a substrate according to claim 1 or 2,
A bonding step of bonding the first substrate and the second substrate between the inclined surface forming step and the irradiation step;
In the second substrate, a structure that is damaged by irradiation with laser light is formed at a position facing the planned cutting surface. A method for manufacturing an electro-optical device, which is formed by joining a first substrate and a second substrate and then cutting along a planned splitting surface.
A slope forming step of forming a slope on one surface along the planned cutting surface of the first substrate;
A bonding step of bonding the first substrate and the second substrate;
An irradiation step of irradiating a laser beam along the planned cutting surface of the first substrate to form a modified portion;
A dividing step of dividing the first substrate and the second substrate,
The method of manufacturing an electro-optical device, wherein, in the irradiation step, irradiation is performed so that a part or all of the laser beam is irradiated onto the inclined surface from a surface opposite to the surface on which the inclined surface is formed. A method for manufacturing the electro-optical device according to claim 5,
In the slope forming step, a concave portion having at least two slopes is formed along the planned splitting surface of the first substrate,
In the irradiation step, the laser beam is irradiated so that the optical axis of the laser beam passes near the apex of the concave portion. A method for manufacturing an electro-optical device according to claim 5 or 6,
An electro-optical device manufacturing method, wherein an electrode or a wiring is formed on the second substrate at a location facing the division planned surface of the first substrate.

Images