JP2008132501A - Laser beam machining apparatus, laser beam machining method and method of manufacturing electro-optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus, a laser beam machining method and a method of manufacturing an electro-optical apparatus by which the increase of energy required for machining is suppressed by suppressing the generation of useless energy which does not contribute to the formation of a property modification zone by suppressing the dispersion of the converging position of a laser beam for forming the property modification zone. <P>SOLUTION: This laser beam machining method is a laser beam machining method by which the mother base material formes a base material body in which a member is stuck onto divided base materials by dividing the mother base material having a plurality of pasted members. The method has a liquid supplying stage where the liquid having a refractive index closer to the refractive index of the member than to the refractive index of the atmosphere is supplied into the space above the mother base material surrounding the member, and a stage of forming the property modification zone where a property modification layer connecting the property modification zones is formed by forming the property modification zone by condensing the laser beam emitted from a laser beam irradiating device in the inside of the mother base material and relatively moving the mother base material and the laser beam irradiating device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus, a laser processing method, and a laser processing apparatus or a method for manufacturing an electro-optical device using the laser processing method.

  Conventionally, as a technique for cutting a workpiece such as a substrate or a wafer along an arbitrary cutting line, a modified region by multiphoton absorption is formed along the planned cutting line inside the workpiece, and the modification is performed. A technique of cutting using a quality region is known. This technique is suitable for fine processing because cutting scraps are not easily generated. In Patent Document 1, a modified region is formed inside a workpiece by irradiating the workpiece with a pulse laser beam using a laser processing apparatus and condensing the pulse laser beam on a portion to be modified. A laser processing method is disclosed. According to this laser processing method, the object to be processed can be cut from the modified region as a starting point by applying a slight force.

  In Patent Document 2, when the thickness of the workpiece is larger than the width of the reformed region in the thickness direction of the workpiece, one cutting scheduled line in the thickness direction of the workpiece is described. By executing the modified region forming process multiple times while changing the position of the condensing point, the modified region is stacked in the thickness direction of the workpiece, and the area of the modified region in the plane direction of the workpiece is A method of forming a modified region over the entire thickness direction without increasing the thickness is disclosed.

  Since these laser processing methods hardly generate cutting waste, there is almost no need to take measures to prevent damage to the workpiece due to the cutting waste, so that it can be suitably used for division in a state close to the final product. . For example, when a large-sized wafer is divided into a state where the process has been advanced to a final product, a large number of display panel substrates are formed, and a counter substrate is attached to each display panel substrate. This is the case when the attached mother board is divided into individual display panels.

JP 2002-192367 A JP 2002-205180 A

  However, when irradiating the processing target with laser light around the small substrate affixed to the processing target, the laser beam that has been emitted so as to be condensed at approximately one point travels in the air. There has been a problem that the condensing position is different between the laser beam reaching the workpiece and the laser beam traveling through the air and the small substrate to reach the workpiece. Specifically, as shown in FIG. 11, the laser light emitted from the objective lens 501 of the condensing lens travels through the air and is condensed at the condensing point F50. However, the light beam 520 that is the light beam at the outermost periphery of the collected light beam is both incident on the small substrate 511 from the upper surface of the small substrate 511 and when emitted from the side surface of the small substrate 511. The traveling direction is refracted downward in FIG. For this reason, the light of the outermost periphery part of a light beam is condensed around the condensing point F55. In this way, the position where light is collected differs depending on the path through which it passes, and the position where the laser light emitted from the objective lens 501 is collected is dispersed from the condensing point F50 to the condensing point F55.

  In order to apply sufficient energy that can form the modified region to the object to be processed even when the converging positions are dispersed, useless energy that does not contribute to the formation of the modified region by dispersing the condensing positions. It was necessary to supply a large amount of energy including That is, there is a problem that energy required for processing increases. When the condensing position in the thickness direction of the processing object is changed as in the processing method disclosed in Patent Document 2, the dispersion of the condensing position also changes, so that all the positions in the thickness direction of the processing object are changed. In order to apply sufficient energy that can form the modified region to the object to be processed, there is a problem that it is necessary to supply larger energy.

  The present invention solves the above-mentioned problem, and suppresses the generation of useless energy that does not contribute to the formation of the reformed region by suppressing the dispersion of the light collection position, thereby enabling processing. An object of the present invention is to realize a laser processing apparatus, a laser processing method, and an electro-optical device manufacturing method capable of suppressing an increase in required energy.

  In the laser processing method according to the present invention, each member of the plurality of members is individually attached on the base material on which the mother base material is divided by dividing the mother base material on which the plurality of members are attached. A laser processing method for forming a substrate body, wherein a liquid that supplies a liquid having a refractive index closer to the refractive index of the member than the refractive index of the atmosphere to the space around the member on the surface of the mother substrate The supply process and the laser light emitted from the laser irradiation device are condensed inside the mother base material to form a modified region, and the mother base material and the laser irradiation device are relatively moved in the plane direction of the mother base material. And a modified layer forming step of forming a modified layer in which the modified regions are continuously or spaced apart from each other.

  According to the laser processing method of the present invention, the modified layer in a state where a liquid having a refractive index closer to the refractive index of the member than the refractive index of the atmosphere is supplied to the space around the member on the mother substrate. A forming step is performed. In order to form a base material in which members are individually attached on the base material, a modified layer is formed in a portion of the mother base material between which the members are attached in the modified layer forming step. In the atmosphere, the laser light emitted from the laser irradiation device and incident on the mother substrate travels only in the atmosphere and enters the mother substrate, and in the atmosphere and members, enters the mother substrate. There is a possibility that there is a part to be. Since the refractive index is different between the atmosphere and the material constituting the member, the laser light is refracted at the part that enters the member from the atmosphere, so the part that travels only in the atmosphere and enters the mother substrate, and the atmosphere The position where light is condensed differs depending on the part that enters the mother substrate through the inside and the member.

  According to the laser processing method of the present invention, since the liquid is supplied to the space around the member on the surface of the mother base, the laser light incident on the mother base is in the atmosphere and liquid. There are a portion that travels inward and enters the mother substrate, and a portion that travels in the atmosphere and in the member and enters the mother substrate. Since the liquid has a refractive index closer to the refractive index of the member than the refractive index of the atmosphere, the laser light is incident on the member from the atmosphere in the part where the laser light enters the liquid from the atmosphere rather than traveling only in the atmosphere. It is refracted in a state close to a state where it is refracted at a portion where the light is refracted. Thereby, the shift | offset | difference of the condensing position resulting from a laser beam being refracted | refracted in the part which injects into a member from the air | atmosphere can be suppressed. By suppressing the deviation of the condensing position, the energy of the laser beam is concentrated in a narrower range and the concentration level of the energy is improved. By suppressing the generation of energy, an increase in energy required for machining can be suppressed.

  In the present invention, the laser processing method includes a cover member that has a flat plate shape on both sides, covers a plurality of members, and a space around the member on the surface of the mother substrate supplied with the liquid. It is preferable to further include a cover member installation step of installing the cover member.

  According to this laser processing method, the surface of the liquid supplied to the space around the member on the surface of the mother substrate contacts the surface of the cover member that covers the portion. Thereby, since the surface of the liquid becomes flat following the surface of the cover member, the surface of the liquid on which the laser light enters can be made a substantially uniform flat surface.

  In the present invention, in the laser processing method, the cover member is preferably formed of a liquid or a material having a refractive index substantially equal to the refractive index of the member.

  According to this laser processing method, there is almost no difference between the refractive index of the cover member and the refractive index of the liquid or member. As a result, almost no refraction of the laser light generated by the difference in refractive index at the boundary between the cover member and the liquid or the member occurs. It is possible to almost eliminate the influence on the.

  In the laser processing method according to the present invention, a mother base material on which a plurality of members are attached is divided, and each member of the plurality of members is individually attached on the base material on which the mother base material is divided. A laser processing method for forming a material, in which a state where a liquid having a refractive index closer to a refractive index of a member than a refractive index of the atmosphere is filled between a laser light emission port of a laser irradiation apparatus and a mother base material While maintaining the above, the laser beam emitted from the laser irradiation device is condensed inside the mother base material to form a modified region, and the mother base material and the laser irradiation device are relatively moved in the plane direction of the mother base material. Thus, it is characterized by having a modified layer forming step of forming a modified layer in which the modified regions are continuously or spaced apart.

  According to the laser processing method of the present invention, the modified layer is filled with a liquid having a refractive index closer to the refractive index of the member than at least the refractive index of the atmosphere between the laser light emission port and the mother substrate. A forming step is performed. In order to form a base material in which members are individually attached on the base material, a modified layer is formed in a portion of the mother base material between which the members are attached in the modified layer forming step. In the atmosphere, the laser light emitted from the laser irradiation device and incident on the mother substrate travels only in the atmosphere and enters the mother substrate, and in the atmosphere and members, enters the mother substrate. There is a possibility that there is a part to be. Since the refractive index is different between the atmosphere and the material constituting the member, the laser light is refracted at the part that enters the member from the atmosphere, so the part that travels only in the atmosphere and enters the mother substrate, and the atmosphere The condensing position is different between the inside and the member and the portion that enters the mother substrate.

  According to the laser processing method of the present invention, since the liquid is supplied between the laser light emission port and the mother base material, the laser light incident on the mother base material travels in the liquid and travels through the mother. There are a portion that enters the base material and a portion that travels through the liquid and the member and enters the mother base material. Laser light traveling only in the liquid travels almost straight. The laser light traveling in the liquid and in the member has a refractive index closer to the refractive index of the member than the refractive index of the atmosphere, so that the laser light is in the atmosphere at the part where the laser light enters the member from the liquid. The light is refracted at a smaller refraction angle that is refracted at a portion incident on the member. Thereby, the shift | offset | difference of the condensing position resulting from a laser beam being refracted in the part which injects into a member can be suppressed. By suppressing the deviation of the condensing position, the energy of the laser beam is concentrated in a narrower range and the concentration level of the energy is improved. By suppressing the generation of energy, an increase in energy required for machining can be suppressed.

  In the present invention, the laser processing method dams the liquid so that the liquid is on the surface of the mother base material and is in a space around the member or between the laser light emission port and the mother base material. It is preferable to maintain.

  According to this laser processing method, since the liquid can be prevented from flowing out by damming the liquid, the liquid is in a space around the member on the surface of the mother substrate, or The state existing between the laser light emission port and the mother substrate can be more reliably maintained as compared with the case where the liquid is not dammed.

  In the present invention, in the laser processing method, it is preferable to form a dam for damming the liquid on the mother base material.

  According to this laser processing method, since the liquid can be prevented from flowing out by damming the liquid with the dam formed on the mother base, the liquid is on the surface of the mother base. The state existing in the space around the member or the state existing between the laser light emission port and the mother base material can be more reliably maintained as compared with the case where no dam is formed.

  In the present invention, in the laser processing method, it is preferable that a dam for damming the liquid is formed on a stage on which the mother substrate is placed.

  According to this laser processing method, since the liquid can be prevented from flowing out by damming the liquid with the dam formed on the stage for placing the mother base material, the liquid can be prevented from flowing out of the mother base. Maintain the state of being on the surface of the material and in the space around the member, or the state of being between the laser beam exit and the mother base material more reliably than when no dam is formed. Can do.

  In the present invention, it is preferable that the laser processing method further includes a liquid repellency process in which the peripheral portion of the mother base is processed to be liquid repellent with respect to the liquid.

  According to this laser processing method, since it is difficult for the liquid to get over the liquid-repellent treated portion, the liquid can be dammed by the peripheral portion of the mother base material treated to be liquid-repellent. Since the liquid is prevented from flowing out by damming the liquid, the liquid is on the surface of the mother base material and in the space around the member, or the laser light emission port and the mother base material The state between the two can be more reliably maintained as compared with the case where the peripheral portion is not treated to be liquid repellent.

  In the present invention, in the laser processing method, the mother substrate may be a mother substrate in which a main substrate constituting the electro-optical device is partitioned, and the member may be a counter substrate constituting the electro-optical device.

  The laser processing apparatus according to the present invention divides a mother base material on which a plurality of members are attached, and a base in which each member of the plurality of members is individually attached on the base material on which the mother base material is divided. A laser processing apparatus for forming a material body, wherein a laser light source that emits laser light and a laser beam that is focused on and irradiated on a mother base An optical element that condenses in the vicinity, a stage having a placement surface for placing the mother substrate, a moving device that relatively moves the optical element and the stage in a direction parallel to the placement surface, and a liquid supply A refractive index of the member on the surface of the mother substrate on the mother substrate placed on the stage by the liquid supply device, at least in the space around the member, than the refractive index of the atmosphere A liquid having a refractive index close to The features.

  According to the laser processing apparatus of the present invention, the liquid supply apparatus supplies a liquid having a refractive index closer to the refractive index of the member than the refractive index of the atmosphere to the space around the member on the mother substrate. The modified layer forming step can be performed in a state where the liquid is supplied around the member on the surface of the mother substrate. In order to form a base material in which members are individually attached on the base material, a modified layer is formed in a portion of the mother base material between which the members are attached in the modified layer forming step. In the atmosphere, the laser light emitted from the laser irradiation device and incident on the mother substrate travels only in the atmosphere and enters the mother substrate, and in the atmosphere and members, enters the mother substrate. There is a possibility that there is a part to be. Since the refractive index is different between the atmosphere and the material constituting the member, the laser light is refracted at the part that enters the member from the atmosphere, so the part that travels only in the atmosphere and enters the mother substrate, and the atmosphere The condensing position is different between the inside and the member and the portion that enters the mother substrate.

  According to the laser processing apparatus of the present invention, since the liquid can be supplied to the space around the member on the surface of the mother base by the liquid supply apparatus, the laser light incident on the mother base is in the atmosphere. There are a portion that travels in the liquid and enters the mother substrate, and a portion that travels in the atmosphere and in the member and enters the mother substrate. Since the liquid has a refractive index closer to the refractive index of the member than the refractive index of the atmosphere, the laser light is incident on the member from the atmosphere in the part where the laser light enters the liquid from the atmosphere rather than traveling only in the atmosphere. It is refracted in a state close to a state where it is refracted at a portion where the light is refracted. Thereby, the shift | offset | difference of the condensing position resulting from a laser beam being refracted | refracted in the part which injects into a member from the air | atmosphere can be suppressed. By suppressing the deviation of the condensing position, the energy of the laser beam is concentrated in a narrower range and the concentration level of the energy is improved. By suppressing the generation of energy, an increase in energy required for machining can be suppressed.

  In the present invention, the laser processing apparatus has a flat plate shape on both sides, a plurality of members, and a cover member that covers the space around the members on the surface of the mother substrate supplied with the liquid. It is preferable to further include a cover member installation device to be installed.

  According to this laser processing apparatus, the cover member is installed by the cover member installation device, so that the space around the member on the surface of the mother substrate to which the member and the liquid are supplied is covered with the cover member. Can do. The surface of the liquid supplied to the space around the member contacts the surface of the cover member that covers the portion. Thereby, the surface of the liquid becomes flat following the surface of the cover member, so that the surface of the liquid on which the laser light is incident can be made a substantially uniform flat surface.

  In the present invention, in the laser processing apparatus, the cover member is preferably formed of a material having a refractive index substantially equal to the refractive index of the liquid or the member.

  According to this laser processing apparatus, there is almost no difference between the refractive index of the cover member and the refractive index of the liquid or member. As a result, almost no refraction of the laser light generated by the difference in refractive index at the boundary between the cover member and the liquid or the member occurs. It is possible to almost eliminate the influence on the.

  In the present invention, it is preferable that the laser processing apparatus supplies the liquid by the liquid supply apparatus so as to maintain a state in which the liquid is filled between the laser light emission port of the optical element and the mother base material.

  According to this laser processing apparatus, the modified layer forming step can be performed while the liquid supply apparatus maintains the liquid-filled state between the laser light emission port of the optical element and the mother base material. . In order to form a base material in which members are individually attached on the base material, a modified layer is formed in a portion of the mother base material between which the members are attached in the modified layer forming step. In the atmosphere, the laser light emitted from the laser irradiation device and incident on the mother substrate travels only in the atmosphere and enters the mother substrate, and in the atmosphere and members, enters the mother substrate. There is a possibility that there is a part to be. Since the refractive index is different between the atmosphere and the material constituting the member, the laser light is refracted at the part that enters the member from the atmosphere, so the part that travels only in the atmosphere and enters the mother substrate, and the atmosphere The condensing position is different between the inside and the member and the portion that enters the mother substrate.

  According to the laser processing apparatus of the present invention, since the liquid is supplied between the laser light emission port and the mother base material, the laser light incident on the mother base material travels in the liquid and travels through the mother. There are a portion that enters the base material and a portion that travels through the liquid and the member and enters the mother base material. Laser light traveling only in the liquid travels almost straight. The laser light traveling in the liquid and in the member has a refractive index that is closer to the refractive index of the member than the refractive index of the atmosphere, so that the laser light is emitted from the atmosphere in the part where the laser light is incident on the member. It is refracted at a smaller refraction angle that is refracted at the part incident on the member. Thereby, the shift | offset | difference of the condensing position resulting from a laser beam being refracted in the part which injects into a member can be suppressed. By suppressing the deviation of the condensing position, the energy of the laser beam is concentrated in a narrower range and the concentration level of the energy is improved. By suppressing the generation of energy, an increase in energy required for machining can be suppressed.

  In the present invention, the laser processing apparatus preferably further includes a dam for damming the liquid.

  According to this laser processing apparatus, since the liquid can be prevented from flowing out by damming the liquid with the dam formed in the laser processing apparatus, the liquid is on the surface of the mother base and the member The state existing in the surrounding space, or the state existing between the laser light emission port and the mother base material can be more reliably maintained as compared with the case where no dam is formed.

  In the present invention, in the laser processing apparatus, it is preferable that the peripheral portion of the stage is treated so as to be liquid repellent with respect to the liquid.

  According to this laser processing apparatus, since it is difficult for the liquid to get over the liquid-repellent treated portion, the liquid can be dammed by the peripheral edge portion of the liquid-repellent treated stage. Since the liquid is prevented from flowing out from the stage by damming the liquid, the liquid is on the surface of the mother substrate and is in the space around the member, or the laser light emission port and the mother The state between the substrate and the substrate can be more reliably maintained as compared with the case where the peripheral portion is not treated with liquid repellency.

  In the present invention, in the laser processing apparatus, the mother substrate may be a mother substrate in which a main substrate constituting the electro-optical device is partitioned and the member may be a counter substrate constituting the electro-optical device.

  A method of manufacturing an electro-optical device according to the present invention is characterized in that a mother electro-optical device substrate in which a plurality of electro-optical devices are partitioned is divided into individual electro-optical devices using the laser processing method described above.

  The electro-optical device manufacturing method according to the present invention contributes to the formation of a modified region for dividing the mother electro-optical device substrate into individual electro-optical devices due to low concentration of laser light. The mother electro-optical device substrate is divided by using a laser processing method capable of suppressing an increase in energy required for processing by suppressing generation of unnecessary energy. Accordingly, an increase in energy required for processing can be suppressed, so that the mother electro-optical device substrate can be divided with less energy consumption, and the electro-optical device can be manufactured with less energy consumption.

  A method of manufacturing an electro-optical device according to the present invention is characterized in that a mother electro-optical device substrate on which a plurality of electro-optical devices are partitioned is divided into individual electro-optical devices using the laser processing apparatus described above.

  The electro-optical device manufacturing method according to the present invention contributes to the formation of a modified region for dividing the mother electro-optical device substrate into individual electro-optical devices due to low concentration of laser light. The mother electro-optical device substrate is divided by using a laser processing apparatus that can suppress an increase in energy required for processing by suppressing generation of unnecessary energy. Accordingly, an increase in energy required for processing can be suppressed, so that the mother electro-optical device substrate can be divided with less energy consumption, and the electro-optical device can be manufactured with less energy consumption.

  Hereinafter, an embodiment of a laser processing apparatus, a laser processing method, and an electro-optical device manufacturing method according to the present invention will be described with reference to the drawings. According to an embodiment of the present invention, in a process of manufacturing a liquid crystal display panel constituting a liquid crystal display device that is an example of an electro-optical device, a mother substrate on which the liquid crystal display panel is partitioned is cut to form individual liquid crystal display panels. A laser processing method and a laser processing apparatus used in the dividing step will be described as an example.

(First embodiment)
<Configuration of LCD panel>
First, a liquid crystal display panel will be described. FIG. 1 is a schematic diagram showing the structure of a liquid crystal display panel. FIG. 1A is a plan view of the liquid crystal display panel as viewed from the counter substrate side together with each component, and FIG. 1B is a cross-sectional shape taken along line AA in FIG. It is a schematic sectional drawing which shows. In each drawing used in the following description, the scale is different for each layer and each member so that each layer and each member can be recognized on the drawing.

  As shown in FIGS. 1A and 1B, a liquid crystal display panel 10 is bonded to an element substrate 1 having a TFT (Thin Film Transistor) element 3, a counter substrate 2 having a counter electrode 6, and a sealing material 4. And a liquid crystal 5 filled in a gap between the element substrate 1 and the counter substrate 2. The outer shape of the element substrate 1 is slightly larger than the counter substrate 2 and is in a state of protruding in a frame shape.

  The element substrate 1 uses a quartz glass substrate having a thickness of about 1.2 mm, and has a pixel electrode (not shown) constituting a pixel on its surface and a TFT in which one of three terminals is connected to the pixel electrode. Element 3 is formed. The remaining two terminals of the TFT element 3 are connected to a data line (not shown) and a scanning line (not shown) which are arranged in a grid pattern so as to surround the pixel electrode and are insulated from each other. The data line is drawn out in the Y-axis direction and connected to the data line driving circuit unit 9a at the terminal unit 16. The scanning lines are drawn out in the X-axis direction and are individually connected to two scanning line driving circuit units 9b formed in the left and right frame regions. The input side wirings of each data line driving circuit unit 9 a and scanning line driving circuit unit 9 b are connected to the mounting terminals 11 arranged along the terminal unit 16, respectively. In the frame region opposite to the terminal portion 16, a wiring 12 that connects the two scanning line driving circuit portions 9b is provided.

  The counter substrate 2 is a transparent quartz glass substrate having a thickness of approximately 1.0 mm, and is provided with a counter electrode 6 as a common electrode. The counter electrode 6 is electrically connected to the wiring provided on the element substrate 1 side through the vertical conduction parts 14 provided at the four corners of the counter substrate 2, and the wiring is also connected to the mounting terminal 11 provided in the terminal part 16. It is connected.

  An alignment film 7 and an alignment film 8 are formed on the surface of the element substrate 1 facing the liquid crystal 5 and the surface of the counter substrate 2, respectively.

  In the liquid crystal display panel 10, a relay substrate that is electrically connected to an external drive circuit is connected to the mounting terminal 11. An input signal from the external drive circuit is input to each data line drive circuit unit 9a and scan line drive circuit unit 9b, whereby the TFT element 3 is switched for each pixel electrode, and the pixel electrode and the counter electrode 6 are switched. In the meantime, a drive voltage is applied to display.

  Although not shown in FIG. 1, polarizing plates are provided on the front and back surfaces of the liquid crystal display panel 10 to polarize incoming and outgoing light, respectively.

<Mother substrate for LCD panel>
Next, a mother substrate 10A in which the liquid crystal display panel 10 is partitioned will be described with reference to FIG. FIG. 2 is a schematic view showing a mother substrate on which a liquid crystal display panel is partitioned. 2A is a schematic plan view of the mother substrate, and FIG. 2B is a schematic cross-sectional view showing a cross-sectional shape in a cross section indicated by BB in FIG. 2A. In addition, in FIG.2 (b), the sealing material 4 is abbreviate | omitting illustration. Although the thickness of the sealing material 4 and the liquid crystal 5 with respect to the thickness of the mother element substrate 1A and the like is very small, in FIG. 1B described above, the liquid crystal 5 and the like are shown thickly.

  As shown in FIGS. 2A and 2B, in the mother substrate 10A, a plurality of element substrates 1 corresponding to one liquid crystal display panel 10 are formed in a wafer-like mother element substrate 1A. The counter substrate 2 is individually bonded to a position corresponding to the element substrate 1 that is partitioned and formed on the mother substrate 10A. One liquid crystal display panel 10 is taken out from the mother substrate 10A by cutting the planned cutting positions along the partition regions Dx and Dy. In this case, the mother element substrate 1A is a quartz glass substrate having a thickness of 1.2 mm and a diameter of 12 inches. On the mother substrate 10A, 200 liquid crystal display panels 10 are partitioned and formed. The counter substrate 2 corresponds to a member, the mother element substrate 1A corresponds to a mother base material, the element substrate 1 corresponds to a base material, and the liquid crystal display panel 10 corresponds to a base material body.

<Laser processing equipment>
Next, the laser processing apparatus used in this embodiment will be described. FIG. 3 is a schematic diagram showing the configuration of the laser processing apparatus.

  As shown in FIG. 3, the laser processing apparatus 100 includes a laser light source 21, a dichroic mirror 22, a condenser lens 23, a Z-axis slide mechanism 24, an imaging device 29, a water supply pump 39, a stage 20, A rotation mechanism 25, an X-axis slide mechanism 27, a Y-axis slide mechanism 26, and a machine base 28 are provided.

  The laser light source 21 is a so-called Nd: YAG laser using, for example, a crystal obtained by doping yttrium-aluminum-garnet with neodymium as a laser medium. The excitation method of the laser light source 21 is, for example, LD excitation. In order to form the modified layer on the mother element substrate 1A made of quartz glass, the laser beam is used by oscillating Nd: YAG-THG (third harmonic).

  The laser light emitted from the laser light source 21 is reflected by the dichroic mirror 22 and condensed inside the workpiece W by the condenser lens 23. The workpiece W is placed on the stage 20 so that the condensing position where the laser light is collected by the condenser lens 23 is located inside the workpiece W. The condenser lens 23 is supported by a slide arm 24 a extending from the Z-axis slide mechanism 24, and the Z-axis slide mechanism 24 moves the condenser lens 23 relative to the workpiece W placed on the stage 20. Is moved to the thickness direction of the workpiece W (Z-axis direction in FIG. 3). The imaging device 29 is located on the opposite side of the condensing lens 23 with the dichroic mirror 22 in between, and takes an image of the workpiece W or the like.

  A water supply nozzle 39a is connected to the water supply pump 39, and water sent from the water supply pump 39 is discharged from the water supply nozzle 39a. The water supply nozzle 39 a is supported by a slide arm 24 b extending from the Z-axis slide mechanism 24, and the Z-axis slide mechanism 24 moves the water supply nozzle 39 a together with the condenser lens 23. The water supply nozzle 39 a is fixed to the condenser lens 23 at a position where water discharged from the water supply nozzle 39 a is supplied to the periphery of the optical axis of the condenser lens 23.

  The machine base 28 is a frame that supports each mechanism constituting the laser processing apparatus 100. An X-axis slide base 27b constituting the X-axis slide mechanism 27 is fixed to the machine base 28, and the X-axis slider 27a constituting the X-axis slide mechanism 27 is slidable and fixable in the X-axis direction. The slide base 27b is engaged. The Y-axis slide base 26b constituting the Y-axis slide mechanism 26 is fixed to the X-axis slider 27a, and the Y-axis slider 26a constituting the Y-axis slide mechanism 26 is slidable and fixable in the Y-axis direction. The shaft slide base 26b is engaged. A rotation mechanism base 25b constituting the rotation mechanism 25 is fixed to the Y-axis slider 26a, and the rotation table 25a constituting the rotation mechanism 25 is rotatable about the Z axis so as to be rotatable. The base 25b is engaged. The X-axis slider 27a, the Y-axis slider 26a, and the rotation table 25a are driven by a servo motor (not shown) configured between the X-axis slide base 27b, the Y-axis slide base 26b, and the rotation mechanism base 25b, respectively. The

  The stage 20 is fixed to the rotary table 25a and is used for placing the workpiece W. The workpiece W placed on the stage 20 is sucked by, for example, a suction device configured on the stage 20 and fixed to the stage 20. The workpiece W fixed to the stage 20 can be rotated around the Z axis by the rotation mechanism 25, and the posture of the condenser lens 23 in the direction parallel to the X axis and the Y axis (plane direction) is set. Adjusted. Further, the workpiece W fixed to the stage 20 is moved in a plane direction parallel to the X axis and the Y axis by the X axis slide mechanism 27 and the Y axis slide mechanism 26, and the workpiece W is arbitrarily selected. Is moved to a position facing the condenser lens 23. The X-axis slide mechanism 27 and the Y-axis slide mechanism 26 correspond to a traveling device. The thickness direction of the workpiece W placed and fixed on the stage 20 is the Z-axis direction.

  The laser processing apparatus 100 includes a main computer 30 as a control unit that controls each of the above components. The main computer 30 includes an image processing unit 34 that processes image information captured by the imaging device 29 in addition to the CPU and various memories. The imaging device 29 incorporates a coaxial incident light source and a CCD (solid-state imaging device). Visible light emitted from the coaxial incident light source passes through the condenser lens 23 and is focused.

  A laser control unit 31, a lens control unit 32, a stage control unit 33, an input unit 35, a display unit 36, and a water supply control unit 38 are connected to the main computer 30. The input unit 35 is used to input data on various processing conditions used during laser processing, and the display unit 36 is used to display various information during laser processing. The laser control unit 31 controls the output, pulse width, and pulse period of the laser light source 21. The lens control unit 32 drives the Z-axis slide mechanism 24 to control the position of the condenser lens 23 in the Z-axis direction. The stage control unit 33 controls a servo motor (not shown) that drives the rotation mechanism 25, the X-axis slide mechanism 27, and the Y-axis slide mechanism 26. The water supply control unit 38 supplies water to the periphery of the optical axis of the condenser lens 23 by controlling the water supply pump 39 to discharge water from the water supply nozzle 39a. The water supply control unit 38, the water supply pump 39, and the water supply nozzle 39a correspond to a liquid supply device.

  The Z-axis slide mechanism 24 that moves the condensing lens 23 in the Z-axis direction has a built-in position sensor capable of detecting the moving distance, and the lens control unit 32 detects the output of the position sensor and collects the light. The position of the lens 23 in the Z-axis direction can be controlled. Therefore, the condensing position of the condensing lens 23 can be adjusted to an arbitrary position from the surface of the workpiece W.

<Formation of modified region>
Here, formation of the modified region by multiphoton absorption will be described. Even if the workpiece W is made of a material that is transparent to the light applied thereto, absorption occurs when the photon energy hν is much larger than the absorption band gap Eg of the material. This absorption is called multiphoton absorption. When multiphoton absorption is caused to occur inside the workpiece W, the energy of the multiphoton absorption is converted into thermal energy, so that microcracks are formed inside the workpiece W. Alternatively, when the pulse width of the laser beam is made extremely short to cause multiphoton absorption to occur inside the workpiece W, the energy of the multiphoton absorption is not converted into thermal energy, but the ionic valence change and crystallization. Alternatively, a permanent structural change such as polarization orientation is induced to form a refractive index change region. In the present embodiment, the region where these micro cracks are formed and the refractive index change region are referred to as a modified region 40 (see FIG. 5).

  When the modified region 40 is formed by the pulsed laser beam, one modified region 40 is formed by one pulse of the laser beam. By forming the modified region 40 while moving the condensing position in the plane direction of the workpiece W, the modified region is arranged continuously or at a slight interval in the plane direction of the workpiece W. 40 rows are formed. The row of the modified region 40 is hereinafter referred to as a modified layer 42 (see FIG. 5 or FIG. 6). The condensing position is moved in the thickness direction of the workpiece W, and a new modified layer 42 is formed at a position overlapping the formed modified layer 42 and the workpiece W in the plane direction. A modified layer 44 (see FIG. 5 or FIG. 6) in which the quality layer 42 is laminated to form the modified region 40 in a plane is formed.

<Separation of LCD panel>
Next, a process of cutting the mother substrate 10A by a laser scribing method using the laser processing apparatus 100 and separating it into individual liquid crystal display panels 10 will be described with reference to FIGS. As described above, in the mother substrate 10A, a plurality of element substrates 1 corresponding to one liquid crystal display panel 10 are formed on the mother element substrate 1A, and the counter substrate 2 is bonded to the element substrate 1 that is individually formed. Has been. By forming a modified band at the boundary of the element substrate 1 formed on the mother element substrate 1A and applying a weak bending force or tensile force in the vicinity of the modified band, the liquid crystal display is separated at the modified band 44 portion. Separate the panel 10.

  FIG. 4 is a flowchart showing a process of cutting a mother substrate by a laser scribing method and separating it into individual liquid crystal display panels. FIG. 5 is a schematic cross-sectional view of a mother element substrate showing a process of forming a modified zone on the mother element substrate, and FIG. 6 is a schematic diagram showing a state in which the mother substrate is divided at a portion where the modified zone is formed. It is. 5 and 6, the sealing material 4 other than the mother element substrate 1A and the counter substrate 2 are not shown.

  In step S <b> 1 shown in FIG. 4, the mother substrate 10 </ b> A is set on the stage 20 as a preparation stage for forming the modified zone 44. First, the mother substrate 10A is fixed to the stage 20, and then the stage 20 is rotated around the Z-axis by the rotation mechanism 25, so that one of the boundaries of the element substrate 1 partitioned on the mother element substrate 1A is formed. The extending direction is made to coincide with, for example, the Y-axis direction in FIG.

  Next, in step S2, the water supply control unit 38 described above controls the water supply pump 39 to discharge the water 60 from the water supply nozzle 39a, thereby supplying the water 60 onto the mother substrate 10A. The supplied water 60 is also supplied to the periphery of the counter substrate 2 so that the gap between the counter substrates 2 is filled with the water 60 as shown in FIG. The water 60 corresponds to the liquid supplied by the liquid supply device.

  Next, in step S3, the cover glass 61 is set on the mother substrate 10A so that the counter substrate 2 and the space around the counter substrate 2 can be covered. The cover glass 61 is formed of the same transparent quartz glass as the counter substrate 2. By setting the cover glass 61 in a state in which the water 60 is sufficiently supplied, the region surrounded by the mother element substrate 1A, the counter substrate 2 and the cover glass 61 is formed by the water 60 as shown in FIG. Satisfied. In addition, the refractive index of quartz glass is about 1.45, the refractive index of water is about 1.33, and the refractive index of air | atmosphere is about 1.00029. The cover glass 61 corresponds to a cover member. The cover glass 61 is set using a cover member installation device similar to the substrate supply device that sets the mother substrate 10A on the stage 20. Alternatively, it may be performed manually.

  Next, in step S4, the mother substrate 10A fixed to the stage 20 is moved in the X-axis direction by the X-axis slide mechanism 27 so that the extending direction of the element substrate 1 coincides with the Y-axis direction. Is set on the optical axis of the condenser lens 23.

  Next, in step S <b> 5, the modified region 40 is formed along the boundary set on the optical axis of the condenser lens 23. As shown in FIG. 5 (c), the laser light emitted from the objective lens 23a of the condenser lens 23 has a refractive index of the atmosphere at the incident point 61a or the incident point 61b incident on the cover glass 61 from the atmosphere. The cover glass 61 is refracted at an angle corresponding to the difference from the refractive index.

  At the incident point 62a incident on the counter substrate 2 from the cover glass 61, the cover glass 61 and the counter substrate 2 are made of the same material and have the same refractive index, so that the laser light travels straight. At the incident point 62 b that enters the water 60 from the cover glass 61, the laser light is refracted at an angle corresponding to the difference in refractive index between the cover glass 61 and the water 60. Since the difference in refractive index between the cover glass 61 and the water 60 is smaller than the difference in refractive index between the cover glass 61 and the atmosphere, the refraction angle at the incident point 62b is the absence of the water 60 due to the presence of the water 60. Smaller than when there is air. The condensing position of the laser light that passes through the water 60 from the cover glass 61 passes through the counter substrate 2 from the cover glass 61 than the condensing position of the laser light that passes through the atmosphere from the cover glass 61 when there is no water 60. It becomes close to the condensing position of the laser beam.

  The laser light is also refracted at an angle corresponding to the difference in refractive index between the counter substrate 2 and the water 60 even at an incident point 63 a that enters the water 60 from the counter substrate 2. Since the difference in refractive index between the counter substrate 2 and the water 60 is smaller than the difference in refractive index between the counter substrate 2 and the atmosphere, the refraction angle when the laser light enters the water 60 from the counter substrate 2 is the laser. It is smaller than the refraction angle when light is incident from the counter substrate 2 into the atmosphere. Therefore, the condensing position of the laser light refracted at the incident point 63a incident on the water 60 from the counter substrate 2 is the collection point of the laser light incident on the atmosphere at the incident point 63a from the counter substrate 2 when there is no water 60. From the light position, the incident point 62b is closer to the condensing position of the laser light that has entered the water 60 or the atmosphere and travels straight.

  Accordingly, the laser light emitted from the objective lens 23a is condensed at a condensing point F56 slightly spreading in the optical axis direction. The spread of the condensing point F56 in the optical axis direction is only slightly spread due to the presence of the water 60, and is smaller than the case where the water 60 does not exist and the atmosphere exists. Since the condensing point F56 has a small spread in the optical axis direction, the energy is concentrated to a degree sufficient to form the modified region 40, and the modified region 40 is formed around the condensing point F56. .

  In order to form the modified zone 44 on substantially the entire cross section of the mother element substrate 1A, first, as shown in FIG. 5 (d), laser light is applied opposite to the laser light incident surface of the mother element substrate 1A. The modified region 40 is formed by collecting light in the vicinity of the side surface. In parallel with the formation of the modified region 40, the Y-axis slide mechanism 26 moves the mother element substrate 1A in the direction of arrow a to form a modified layer 42 in which the modified regions 40 are continuous or continuous. . As described above, the laser light source 21 that is a laser light source is an LD-excited Nd: YAG laser. In the present embodiment, a third harmonic having a wavelength of 355 nm is used. The modified region 40 by the laser beam having a wavelength of 355 nm is a micro crack formation region in which micro cracks are formed.

  When the formation of the single modified layer 42 is completed, the condensing position is moved in the thickness direction of the mother element substrate 1A, and the modified layer 42 is similarly formed at the position, thereby the mother element substrate 1A. The modified layer 42 is laminated in the thickness direction. Finally, as shown in FIG. 5E, the laser light is condensed near the laser light incident surface of the mother element substrate 1A to form the modified region 40, and the mother element substrate 1A is moved to the arrow. By moving in the direction a, a modified layer 42 is formed in the vicinity of the incident surface, and as shown in FIG. 5 (f), a modified zone 44 is formed on substantially the entire cross section of the mother element substrate 1A. To do.

  Next, in step S6 of FIG. 4, it is determined whether or not the modified zone 44 has been formed over substantially the entire cross section of the mother element substrate 1A. If the formation of the reforming zone 44 has not been completed (NO in step S6), the process returns to step S5, and steps S5 and S6 are repeated to form the reforming zone 44 by laminating the reforming layer 42. To do. If the formation of the modified zone 44 has been completed (YES in step S6), the process proceeds to step S7, and whether or not the modified zone 44 has been formed at all the boundaries of the element substrate 1, that is, formed. It is determined whether or not the formation of all the reformed zones 44 to be completed is completed.

  If the formation of all the reforming zones 44 has not been completed (NO in step S7), the process returns to step S4, and steps S4 to S7 are repeated to form the reforming zone 44. If formation of all the reforming zones 44 has been completed (YES in step S7), the process proceeds to step S8.

  In step S8, the mother substrate 10A is removed from the stage 20. At this time, the cover glass 61 is also removed from the mother substrate 10A.

  Next, in step S9, the mother substrate 10A is separated into individual liquid crystal display panels 10. FIG. 6 is a schematic diagram showing a state in which the mother substrate is divided at the portion where the modified zone is formed. By applying a force so as to separate both sides sandwiching the reforming zone 44, the portion of the reforming zone 44 is divided. For example, as shown in FIG. 6A, a pressing jig 50 is pressed on a straight line on which the modified band 44 is formed to apply stress to the vicinity of the mother element substrate 1A where the modified band 44 is formed. As shown in FIG. 6B, the mother element substrate 1A that has been subjected to stress is divided at the surface on which the modified band 44 is formed, using the modified band 44 as a trigger. Separated into individual liquid crystal display panels 10.

The effects of the first embodiment will be described below. According to the first embodiment, the following effects can be obtained.
(1) The difference in refractive index between the cover glass 61 and the water 60 is smaller than the difference in refractive index between the cover glass 61 and the atmosphere. For this reason, when the periphery of the counter substrate 2 is filled with water 60 having a refractive index closer to the counter substrate 2 than the atmosphere, the condensing position of the laser light that passes through the water 60 from the cover glass 61 is changed from the cover glass 61 to the atmosphere. It is closer to the condensing position of the laser light that passes through the counter substrate 2 from the cover glass 61 than the condensing position of the laser light when passing through the inside. Therefore, the difference between the condensing position of the laser light that passes through the counter substrate 2 and the condensing position of the laser light that does not pass through the counter substrate 2 can be reduced.

  (2) Since the difference in refractive index between the counter substrate 2 and the water 60 is smaller than the difference in refractive index between the counter substrate 2 and the atmosphere, the refraction angle when the laser light enters the water 60 from the counter substrate 2. Is smaller than the refraction angle when the laser light is incident from the counter substrate 2 into the atmosphere. Therefore, the condensing position of the laser light refracted at the incident point 63a incident on the water 60 from the counter substrate 2 is the collection point of the laser light incident on the atmosphere at the incident point 63a from the counter substrate 2 when there is no water 60. From the light position, the incident point 62b is closer to the condensing position of the laser light that has entered the water 60 or the atmosphere and travels straight. Accordingly, by filling the periphery of the counter substrate 2 with water 60 having a refractive index closer to the counter substrate 2 than the atmosphere, the condensing position of the laser beam that passes through the counter substrate 2 and the collection of laser light that does not transmit through the counter substrate 2 are obtained. The difference from the light position can be reduced.

  (3) By providing the cover glass 61 having a flat surface, the surface of the water 60 in contact with the cover glass 61 is flattened, so that the laser light is incident on the non-flat surface and the direction of the laser light varies. It is possible to suppress the spread of the lighted position.

(Second embodiment)
Next, a second embodiment of the laser processing apparatus, the laser processing method, and the electro-optical device manufacturing method according to the present invention will be described. The laser processing apparatus of this embodiment is substantially the same as the laser processing apparatus 100 described in the first embodiment. Only the configuration and operation of the liquid supply apparatus different from the first embodiment will be described.

<Configuration of liquid supply device>
Initially, the structure of the liquid supply apparatus of the laser processing apparatus used by this embodiment is demonstrated. FIG. 7 is a schematic diagram illustrating a configuration of the liquid supply device and a state in which water is supplied from the liquid supply device.

  As shown in FIG. 7, the liquid supply device includes a plurality of water supply nozzles 69a. Although omitted in FIG. 7 and only two water supply nozzles 69 a are shown, the six water supply nozzles 69 a have their tips directed toward the periphery of the outlet of the condenser lens 231, and the Z-axis slide mechanism 24 (FIG. 3). Similar to the condensing lens 23 described in the first embodiment, the condensing lens 231 is fixed to the Z-axis slide mechanism 24 via a slide arm 24a. The laser light emitted from the laser light source is reflected by the dichroic mirror 22 and is condensed inside the object to be processed such as the mother element substrate 1A by the condenser lens 231. Each of the six water supply nozzles 69a is connected to a water supply pump not shown in FIG. In the case where the modified layer 42 is formed by forming the modified region 40 by irradiating laser light, the objective lens 23a of the condenser lens 231 and the mother substrate 10A are in contact with each other during the formation process. The water 60 is continuously supplied from the six water supply nozzles 69a so that the space 60 is filled with water.

<Condensing position>
Next, the laser beam condensing position in the laser processing apparatus having the liquid supply apparatus position of this embodiment will be described. When the laser light emitted from the objective lens 23a travels only in the water 60 and enters the mother element substrate 1A, the laser light is condensed at the condensing point F65. Since the laser light emitted from the objective lens 23a and traveling between the opposing substrates 2 travels only in the water 60 and enters the mother element substrate 1A, the laser light travels straight from the objective lens 23a to the mother element substrate 1A and is condensed. Condensed to point F65. The light at the outermost periphery of the laser beam emitted from the objective lens 23a is incident on the counter substrate 2 from the water 60 at the incident point 64a, and is incident on the water 60 from the counter substrate 2 at the incident point 64b. Condensate to F66. The condensing position differs depending on the optical path length passing through the counter substrate 2, and the laser light emitted from the objective lens 23a is condensed between the condensing point F65 and the condensing point F66.

  At the incident point 64 a that enters the counter substrate 2 from the water 60, the laser light is refracted at an angle corresponding to the difference in refractive index between the water 60 and the counter substrate 2. Since the difference in refractive index between the water 60 and the counter substrate 2 is smaller than the difference in refractive index between the atmosphere and the counter substrate 2, the refraction angle at the incident point 64 a is the absence of the water 60 due to the presence of the water 60. Smaller than when there is air. The incident point 64b that enters the water 60 from the counter substrate 2 is refracted at an angle corresponding to the difference in refractive index between the counter substrate 2 and the water 60. Since the difference in refractive index between the counter substrate 2 and the water 60 is smaller than the difference in refractive index between the counter substrate 2 and the atmosphere, the refraction angle when the laser light enters the water 60 from the counter substrate 2 is the laser. This is smaller than the refraction angle when light enters the atmosphere from the counter substrate 2. Therefore, the position of the condensing point F66 is closer to the condensing point F65 than the position where the laser light that passes through the counter substrate 2 and enters the mother element substrate 1A when there is no water 60 is condensed. Since the distance between the condensing point F65 where the laser beam is condensed and the condensing point F66 is small, the energy is concentrated to a degree sufficient to form the modified region 40. The modified region 40 is formed around F66.

The effects of the second embodiment will be described below. According to the second embodiment, in addition to the effects of the first embodiment described above, the following effects can be obtained.
(1) The space between the objective lens 23a and the mother substrate 10A is filled with water 60, and the laser light emitted from the objective lens 23a enters the counter substrate 2 from the water 60. Since the difference in refractive index between the counter substrate 2 and the water 60 is smaller than the difference in refractive index between the counter substrate 2 and the atmosphere, the refraction angle when the laser light is incident on the counter substrate 2 from the water 60 is the laser. This is smaller than the refraction angle when light enters the counter substrate 2 from the atmosphere. Thereby, the shift | offset | difference of the condensing position by the influence of the said refraction can be suppressed.

  (2) The space between the objective lens 23a and the mother substrate 10A is filled with water 60, and the laser light emitted from the objective lens 23a enters the mother substrate 10A without entering the water 60 from the atmosphere. . Since the light does not enter the water 60 from the atmosphere, the light is not refracted when entering the water 60 from the air, so that the shift of the condensing position due to the influence of the refraction can be suppressed.

(Third embodiment)
Next, a third embodiment of the laser processing apparatus, the laser processing method, and the electro-optical device manufacturing method according to the present invention will be described. The laser processing apparatus of this embodiment is substantially the same as the laser processing apparatus 100 described in the first or second embodiment. Only the configuration of the stage different from the first or second embodiment will be described.

<Stage structure>
Initially, the structure of the stage 80 of the laser processing apparatus used by this embodiment is demonstrated with reference to FIG. FIG. 8 is a schematic diagram showing the configuration of the stage and the drainage device. FIG. 8A is a plan view of the stage and a schematic diagram showing the configuration of the drainage device, and FIG. 8B is a cross-sectional view of the stage.

  As shown in FIG. 8, the stage 80 is a workpiece holding device that places and holds a workpiece such as the mother substrate 10 </ b> A, and has a suction hole and a suction communicating with a negative pressure device (not shown). A suction groove 82 communicating with the hole is formed on the placement surface 83 on which the workpiece is placed. The mother substrate 10 </ b> A placed on the stage 80 can be adsorbed and fixed to the stage 80 by a negative pressure device, a suction hole, and a suction groove 82.

  A dam portion 81 protruding from the placement surface 83 is formed on the periphery of the placement surface 83 so as to surround the entire circumference of the placement surface 83. By supplying the water 60 from the water supply nozzle 39a or the water supply nozzle 69a of the liquid supply apparatus described in the first or second embodiment, as shown in FIG. A state in which a workpiece such as 10A is immersed in water 60 can be maintained. The dam portion 81 corresponds to a dam.

  In the mounting surface 83, drainage grooves 86 are formed at positions surrounding the suction groove 82, and four drainage holes 84 communicating with the drainage pump 89 are formed at the bottom of the drainage groove 86. . The drainage pump 89 is controlled by the drainage control unit 88 to suck the liquid accumulated in the drainage hole 84 through the drainage hole 84.

The effects of the third embodiment are described below. According to 3rd embodiment, in addition to the effect of 1st or 2nd embodiment mentioned above, the following effects are acquired.
(1) The state where the liquid has accumulated on the mounting surface 83 can be maintained by the dam 81 that protrudes from the mounting surface 83 and surrounds the entire circumference of the mounting surface 83. By holding the water 60 supplied from the liquid supply device on the mounting surface 83, the state in which the water 60 is filled around the counter substrate 2 described in the first or second embodiment, or the objective A state where the space between the lens 23a and the mother substrate 10A is filled with water 60 can be easily realized.

  (2) By the drainage groove 86, the drainage hole 84, the drainage pump 89, and the drainage control unit 88, the liquid accumulated on the mounting surface 83 can be easily discharged.

(Fourth embodiment)
Next, a fourth embodiment of the laser processing apparatus, the laser processing method, and the electro-optical device manufacturing method according to the present invention will be described. The laser processing apparatus of this embodiment is substantially the same as the laser processing apparatus 100 described in the first or second embodiment. Only the configuration of the mother substrate 90 </ b> A of the liquid crystal display panel, which is an example of a processing object different from the first or second embodiment, will be described.

<Mother substrate for LCD panel>
The mother substrate 90A is a mother substrate in which the liquid crystal display panel 10 described in the first embodiment is partitioned. The mother substrate 90A will be described with reference to FIG. FIG. 9 is a schematic view showing a mother substrate on which a liquid crystal display panel is formed. FIG. 9A is a schematic plan view of the mother substrate, and FIG. 9B is a schematic cross-sectional view showing a cross-sectional shape taken along the line CC in FIG. 9A. In addition, in FIG.9 (b), the sealing material 4 (refer FIG. 1) is abbreviate | omitting illustration.

  As shown in FIGS. 9A and 9B, in the mother substrate 90A, a plurality of element substrates 1 corresponding to one liquid crystal display panel 10 are formed on a wafer-like mother element substrate 91A. The counter substrate 2 is individually bonded to a position corresponding to the element substrate 1 that is partitioned and formed on the mother substrate 90A. One liquid crystal display panel 10 is taken out from the mother substrate 90A by cutting the planned cutting positions along the partition regions Dx and Dy.

  A dam portion 92 protruding from the surface of the mother element substrate 91A is formed on the periphery of the mother element substrate 91A so as to surround the entire circumference of the mother element substrate 91A. By supplying the water 60 from the water supply nozzle 39a or the water supply nozzle 69a of the liquid supply apparatus described in the first or second embodiment with the mother element substrate 91A placed on the stage 20 (see FIG. 3). As shown in FIG. 9B, the processing object such as the mother substrate 10 </ b> A can be maintained in the water 60 inside the dam portion 92. The mother element substrate 91A corresponds to a mother base material, and the dam portion 92 corresponds to a dam.

The effects of the fourth embodiment will be described below. According to the fourth embodiment, in addition to the effects of the first or second embodiment described above, the following effects can be obtained.
(1) By the dam portion 92 that protrudes from the surface of the mother element substrate 91A and surrounds the entire circumference of the mother element substrate 91A, it is possible to maintain a state where liquid is accumulated on the surface of the mother element substrate 91A. By holding the water 60 supplied from the liquid supply device on the surface of the mother element substrate 91A, the state where the water 60 is filled around the counter substrate 2 described in the first or second embodiment, Alternatively, a state where the space between the objective lens 23a and the mother substrate 10A (mother substrate 90A) is filled with water 60 can be easily realized.

  As mentioned above, although preferred embodiment which concerns on this invention was described referring an accompanying drawing, embodiment of this invention is not restricted to the said embodiment. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention, and can be implemented as follows.

  (Modification 1) In the first embodiment, the modified glass band 61 is set on the mother substrate 10 </ b> A so as to cover the counter substrate 2 and the gap around the counter substrate 2. Although the process of forming 44 is performed, it is not essential to use the cover glass 61. As shown in FIG. 10, the space around the counter substrate 2 may be simply filled with water 60 without using the cover glass 61.

  FIG. 10 is a schematic diagram illustrating a laser beam condensing position in a state where the space around the counter substrate is filled with water. As shown in FIG. 10, the light at the outermost periphery of the laser light emitted from the objective lens 23a and transmitted through the counter substrate 2 is condensed at the condensing point F67, and the light not transmitted through the counter substrate 2 is collected. It is condensed on the light spot F68. The laser light emitted from the objective lens 23a is condensed in the range from the condensing point F67 to the condensing point F68.

  The laser light emitted from the objective lens 23a is refracted at an angle according to the difference in refractive index between the atmosphere and the counter substrate 2 at an incident point 67a that enters the counter substrate 2 from the atmosphere. At the incident point 68 a that enters the water 60 from the atmosphere, the laser light is refracted at an angle corresponding to the difference in refractive index between the atmosphere and the water 60. Since the refractive index of the water 60 is closer to the refractive index of the counter substrate 2 than the refractive index of the atmosphere, the refraction angle at the incident point 68a is higher than that when the laser beam travels straight in the absence of the water 60. It becomes close to the refraction angle at 67a.

  The laser light is also refracted at an angle corresponding to the difference in refractive index between the counter substrate 2 and the water 60 even at an incident point 67 b that enters the water 60 from the counter substrate 2. Since the difference in refractive index between the counter substrate 2 and the water 60 is smaller than the difference in refractive index between the counter substrate 2 and the atmosphere, the refraction angle when the laser light enters the water 60 from the counter substrate 2 is the laser. It is smaller than the refraction angle when light is incident from the counter substrate 2 into the atmosphere. Accordingly, the condensing position of the laser light refracted at the incident point 67b incident on the water 60 from the counter substrate 2 is the collection point of the laser light incident on the atmosphere from the counter substrate 2 at the incident point 67b when there is no water 60. From the light position, the laser beam enters the water 60 at the incident point 68a or goes straight in the atmosphere, and becomes closer to the condensing position of the laser light that goes straight further.

  Accordingly, by reducing the influence of refraction generated at the incident point 67a and the incident point 67b in order to transmit the counter substrate 2, the amount of separation of the condensing point F67 from the condensing point F68 is reduced, so that the laser beam can be obtained. The range from the condensing point F67 to be condensed to the condensing point F68 can be reduced. As a result, the energy concentration of the laser beam is concentrated in a narrower range and the energy concentration level is improved, so that the generation of useless energy that does not contribute to the formation of the modified region because the concentration level is low, An increase in energy required for processing can be suppressed.

  (Modification 2) In the fourth embodiment, the dam portion 92 is formed on the periphery of the mother element substrate 91A in order to dam the water 60. However, a wafer such as the mother element substrate 91A is used to dam the liquid. It is not essential to provide a dam in The entire periphery of the peripheral edge of the wafer may be processed so as to be liquid repellent with respect to a liquid such as water.

  Since the liquid repellent part is difficult to get wet with the liquid, the liquid is difficult to get over the liquid repellent part. Therefore, the liquid surrounded by the liquid-repellent portion is unlikely to overflow outside the liquid-repellent portion, so that the liquid is collected on the wafer surface by the liquid-repellent portion surrounding the entire circumference of the wafer. Can be maintained. By holding the liquid supplied from the liquid supply device on the surface of the wafer, the state where the water 60 is filled around the counter substrate 2 described in the first or second embodiment, or the objective lens 23a. It is possible to easily realize a state in which the space between the substrate and the mother substrate 10A (wafer) is filled with water 60.

  (Modification 3) In the above embodiment, the example in which the periphery of the counter substrate 2 or the space between the objective lens 23a and the mother substrate 10A is filled with water 60 has been described. However, the periphery of the counter substrate 2 or the objective lens 23a is described. The liquid that fills the space between the mother board 10A and the mother board 10A is not limited to water. If the refractive index of the liquid is closer to the refractive index of the counter substrate 2 than the refractive index of the atmosphere, the effect described in the above embodiment can be obtained. In addition, when the refractive index of the liquid is equal to the refractive index of the counter substrate 2, the influence of the laser light passing through the counter substrate 2 can be almost eliminated. Therefore, the refractive index of the liquid is preferably closer to the refractive index of the counter substrate 2.

  (Modification 4) In the above embodiment, the stage 20 is moved in the direction orthogonal to the Z axis with respect to the condenser lens 23 to move the condenser lens 23 and the mother substrate 10A relative to each other. It is not essential to move the stage 20 side. The relative movement between the condenser lens 23 and the mother substrate 10A may be executed by moving the condenser lens 23 side.

  (Modification 5) In the embodiment described above, the scanning direction of each scan forming the modified region is the same direction, but it is not essential that the scanning direction of each scan is the same direction. The scanning direction may be changed for each modified layer to be stacked. By forming the modified layer by scanning in both reciprocating directions, the time for forming the modified zone can be shortened compared to the case where the scanning direction of each scan is a single direction.

  (Modification 6) In the above-described embodiment, the substrate to be processed is a quartz glass substrate. However, the present invention is not limited to a silicon substrate such as a semiconductor, a quartz substrate made of quartz, Pyrex (registered trademark), or neoceram. (Registered trademark) and a substrate made of OA-10 can also be applied.

  (Modification 7) In the above-described embodiment, the laser light source 21 is an Nd: YAG laser that uses a yttrium-aluminum-garnet-doped neodymium crystal as a laser medium. However, the laser light source uses another laser medium. It may be a laser light source. For example, another YAG laser, YLF laser, YVO4 laser, or the like can be used. In addition to the third harmonic, the Nd: YAG fundamental wave can also be used for the Nd: YAG laser. Note that it is preferable to select an appropriate laser medium or laser light to be oscillated according to the material to be processed.

  (Modification 8) In the above embodiment, the liquid crystal display panel of the liquid crystal display device as the electro-optical device has been described. However, the present invention can also be applied to the manufacture of an electro-optical device other than the liquid crystal display device. For example, the present invention can be applied to the manufacture of an organic EL (electroluminescence) display device.

  (Modification 9) In the above embodiment, the modified layer formed by connecting the modified regions so as to be substantially connected to each other has been described as an example. However, the modified regions constituting the modified layer are substantially connected. That is not essential. As long as it can be divided by applying a small stress, the modified regions may be connected to each other at an interval. By separating the interval, the relative movement speed can be increased compared to the configuration in which the modified regions are substantially connected, and the processing speed when forming the modified layer can be increased. On the other hand, the modified region having a configuration in which the modified regions are connected so as to be substantially connected to each other as in the above-described embodiment is more easily divided than the configuration in which the intervals are separated.

  (Modification 10) In the above-described embodiment, the modified zone having a configuration in which the modified layers are stacked with a space therebetween is described as an example. However, it is not essential that the modified layers are stacked with a space therebetween. As long as it can be divided by applying a small stress, the modified layers may be laminated so as to be substantially connected to each other even if the modified layers are laminated with a space therebetween. By laminating the modified layers so as to be substantially connected to each other, the modified layers are easily divided as compared with the configuration in which the intervals are separated. On the other hand, by separating the intervals as in the above-described embodiment, the time required for forming the modified zone can be shortened as compared with the configuration in which the modified layers are substantially connected.

  (Modification 11) In the embodiment described above, the position adjustment in the Z-axis direction of the condensing position with respect to the mother substrate 10A is performed by moving the condensing lens 23 or the condensing lens 231 by the Z-axis slide mechanism 24. However, it is not essential to move the condenser lens 23 or the condenser lens 231. The position adjustment in the Z-axis direction of the light collection position with respect to the mother substrate 10A may be adjusted by moving the stage 20 in the Z-axis direction. The laser light irradiation device including the laser light source 21 and the condensing lens 23 does not need to have an adjustment device, and the entire laser light irradiation device can be made lighter and smaller than when the laser light irradiation device has an adjustment device.

  (Modification 12) In the third embodiment, the dam portion 81 is formed on the periphery of the mounting surface 83 of the stage 80 in order to dam the water 60. However, the dam is provided to dam the liquid. Is not required. You may process so that the perimeter of the peripheral part of a stage may become liquid repellency with respect to liquids, such as water.

  Since the liquid repellent part is difficult to get wet with the liquid, the liquid is difficult to get over the liquid repellent part. Therefore, since the liquid surrounded by the liquid repellent part is unlikely to overflow outside the liquid repellent part, the liquid collected on the stage mounting surface by the liquid repellent part surrounding the entire circumference of the stage. The state can be maintained. By holding the liquid supplied from the liquid supply device on the mounting surface, the state in which the water 60 is filled around the counter substrate 2 described in the first or second embodiment, or the objective lens 23a. It is possible to easily realize a state in which the space between the mother board 10 </ b> A and the mother board 10 </ b> A is filled with water 60.

The schematic diagram which shows the structure of a liquid crystal display panel. Schematic which shows the mother board | substrate with which the liquid crystal display panel was dividedly formed. The schematic diagram which shows the structure of the laser processing apparatus of this invention. The flowchart which shows the process of cut | disconnecting a mother board | substrate by a laser scribing method, and isolate | separating into each liquid crystal display panel. The schematic cross section of a mother element board | substrate which shows the process of forming a modification zone | band in a mother element board | substrate. The schematic diagram which shows a mode that a mother board | substrate is parted in the part in which the modification | reformation zone was formed. The schematic diagram which shows the state in which water was supplied from the structure of the liquid supply apparatus and the liquid supply apparatus in 2nd embodiment. The schematic diagram which shows the structure of the stage and drainage apparatus in 3rd embodiment. Schematic which shows the mother board | substrate with which the liquid crystal display panel was dividedly formed in 4th embodiment. The schematic diagram which shows the condensing position of the laser beam in the state which filled the space around the counter substrate in water in the modification. The schematic diagram which shows the condensing position of the laser beam by the conventional laser processing method or laser processing apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Element substrate, 1A, 91A ... Mother element substrate, 2 ... Counter substrate, 10 ... Liquid crystal display panel, 10A, 90A ... Mother substrate, 20 ... Stage, 21 ... Laser light source, 23, 231 ... Condensing lens, 23a ... Objective lens, 24 ... Z-axis slide mechanism, 25 ... Rotation mechanism, 26 ... Y-axis slide mechanism, 27 ... X-axis slide mechanism, 30 ... Main computer, 31 ... Laser control unit, 38 ... Water supply control unit, 39 ... Water supply Pump, 39a, 69a ... water supply nozzle, 40 ... reforming region, 42 ... reforming layer, 44 ... reforming zone, F56, F65, F66, F67, F68 ... condensing point, 60 ... water, 61 ... cover glass, 61a, 62a, 62b, 63a, 64a, 64b, 67a, 67b, 68a ... incidence point, 80 ... stage, 81 ... dam part, 83 ... mounting surface, 92 ... dam part, 100 ... laser processing equipment , W ... workpiece.

Claims (18)

By dividing the mother base material to which a plurality of members are attached, a base body in which each member of the plurality of members is individually attached on the base material to which the mother base material is divided is formed. A laser processing method,
A liquid supply step of supplying a liquid having a refractive index closer to the refractive index of the member than the refractive index of the atmosphere to the space around the member on the surface of the mother base;
A laser beam emitted from a laser irradiation device is condensed inside the mother base material to form a modified region, and the mother base material and the laser irradiation device are relatively moved in the plane direction of the mother base material. And a modified layer forming step of forming a modified layer in which the modified regions are continuously or spaced apart from each other.   A cover member having a flat plate-like shape on both sides, the cover member being installed on the surface of the mother base material to which the plurality of members and the liquid are supplied and covering a space around the member The laser processing method according to claim 1, further comprising an installation step.   The laser processing method according to claim 2, wherein the cover member is made of a material having a refractive index substantially equal to a refractive index of the liquid or the member. A laser that divides a mother base material to which a plurality of members are attached, and forms a base body in which each member of the plurality of members is individually attached on the base material on which the mother base material is divided. A processing method,
While maintaining a state in which a liquid having a refractive index closer to the refractive index of the member than the refractive index of the atmosphere is filled between the laser light emission port of the laser irradiation device and the mother base, the laser irradiation device The modified laser beam is condensed inside the mother base material to form a modified region, and the mother base material and the laser irradiation device are moved relative to each other in the plane direction of the mother base material. A laser processing method comprising a modified layer forming step of forming a modified layer in which the quality regions are continuously or spaced apart.   By damming the liquid, the liquid is maintained on the surface of the mother base and in a space around the member, or between the laser light emission port and the mother base. The laser processing method according to any one of claims 1 to 4, wherein:   6. The laser processing method according to claim 5, wherein a dam for damming the liquid is formed on the mother base material.   6. The laser processing method according to claim 5, wherein a dam for damming the liquid is formed on a stage on which the mother substrate is placed.   6. The laser processing method according to claim 1, further comprising a liquid repellency process in which a peripheral portion of the mother base is processed to be liquid repellent with respect to the liquid.   9. The mother substrate is a mother substrate in which a main substrate constituting an electro-optical device is partitioned, and the member is a counter substrate constituting the electro-optical device. The laser processing method as described in any one of these. Dividing a mother base material to which a plurality of members are attached, and forming a base body in which each member of the plurality of members is individually attached on the base material to which the mother base material is divided The laser processing apparatus of
A laser light source for emitting laser light;
An optical element that condenses the laser light and irradiates the mother base material so as to condense the laser light near one point inside the mother base material, and
A stage having a placement surface for placing the mother substrate;
A moving device that relatively moves the optical element and the stage in a direction parallel to the mounting surface;
A liquid supply device,
By the liquid supply device, on the surface of the mother base material on the mother base material placed on the stage, in the space around the member, at least the refractive index of the member from the refractive index of the atmosphere A laser processing apparatus for supplying a liquid having a close refractive index.   Cover member installation which has a flat plate-like shape on both sides, and which covers the plurality of members and a cover member which covers the space around the members on the surface of the mother substrate supplied with the liquid The laser processing apparatus according to claim 10, further comprising an apparatus.   The laser processing apparatus according to claim 11, wherein the cover member is formed of a material having a refractive index substantially equal to a refractive index of the liquid or the member.   11. The liquid is supplied by the liquid supply device so as to maintain a state in which the liquid is filled between a laser light emission port of the optical element and the mother base material. The laser processing apparatus as described in.   The laser processing apparatus according to claim 10, further comprising a dam for damming the liquid.   The laser processing apparatus according to any one of claims 10 to 13, wherein a peripheral portion of the stage is processed to be liquid repellent with respect to the liquid.   16. The mother substrate is a mother substrate in which a main substrate constituting an electro-optical device is partitioned, and the member is a counter substrate constituting the electro-optical device. The laser processing apparatus as described in any one of these.   A mother electro-optical device substrate in which a plurality of electro-optical devices are partitioned is divided into the individual electro-optical devices using the laser processing method according to claim 1. Manufacturing method of electro-optical device.   A mother electro-optical device substrate on which a plurality of electro-optical devices are partitioned is divided into individual electro-optical devices using the laser processing apparatus according to claim 10. Manufacturing method of electro-optical device.

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