JP2010095414A - Method for cutting mother glass substrate for display and brittle material substrate, and method for manufacturing display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a number of processes on cutting laminated glass. <P>SOLUTION: A method for cutting the mother glass substrate 1 of a display panel including a first glass substrate G1 and a second glass substrate G2 laminated together by a sealing material 5 partitioning a plurality of cells arranged in a matrix form is provided. In a first process, a scheduled process line L1 is arranged in a gap between the sealing materials 5 of the adjacent cells, and a laser beam is irradiated along the scheduled process line L1 to form a scribe line on the first glass substrate G1. In a second process, a laser beam is irradiated along the scheduled process line L1 on the second glass substrate G2, and the vicinity of an area 40 to be irradiated by a laser beam is cooled to break the second glass substrate G2. Stress, generated when the second glass substrate G2 is broken, reaches the first glass substrate G1 through the sealing material 5, thereby the first glass substrate G1 is broken along the scribe line at substantially same time with the breakage of the second glass substrate G2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technology for processing a brittle material substrate such as a glass substrate or a semiconductor substrate.

  An FPD (flat panel display) including a liquid crystal display, a plasma display, and an organic EL display is formed by cutting a single mother glass substrate into a plurality of regions of a predetermined size. The size of FPD ranges from several tens of inches used for large LCD TVs to several inches used for mobile phone terminals, and the thickness of FPDs varies from several mm used for large LCD TVs. Wide range of several hundred μm used for mobile phone terminals.

  As a method of cutting a brittle material substrate such as glass, conventionally, a technique of forming a scribe line with a cutter such as diamond and breaking (cleaving) along the scribe line has been used. This method has a problem that glass powder and glass cullet are generated at the time of cleaving. In recent years, a technique (laser scribing) that uses a laser beam instead of a cutter for forming a scribe line has been developed.

  In laser scribing, while moving on a glass substrate along a planned processing line, a laser is irradiated to one point on the planned processing line to locally heat it, and then a cooling medium is injected near the heating region to cool it. As a result, according to the heat distribution on the laser substrate, thermal stress is generated in the direction of pulling the glass substrate perpendicular to the planned processing line, and a scribe line along the planned processing line grows on the glass substrate. Thereafter, mechanical stress is applied to the glass substrate by a breaker device as necessary, and the glass substrate is cut along the scribe line.

In addition, by adjusting heating conditions, cooling conditions, processing speed, etc., the scribe line is penetrated to the deep part in the thickness direction of the glass substrate, and the full cut that cleaves the glass substrate without breaking by the breaker device (Also called full body cut). A full cut using a laser is very useful from the viewpoint of mass productivity because it requires no post-processing by a breaker device and can cleave the glass substrate in a single step.
International Publication No. 03/008168 Pamphlet JP 2007-52188 A JP 2002-153984 A JP 2005-080032 A

  The mother glass substrate is composed of two glass substrates bonded together by a sealing material. In the manufacturing process of the liquid crystal panel, it is necessary to cut the four sides of each cell substrate from the mother glass substrate having a plurality of cell substrates sealed on the four sides to cut out the individual sides.

  At this time, first, scribe lines are formed in the vertical direction and the horizontal direction with respect to the front surface side substrate (first substrate), and then the mother glass substrate is reversed to the back side substrate (second substrate). Then, scribe lines are formed in the vertical direction and the horizontal direction (scribing step). Subsequently, the second substrate is cleaved along the scribe line, the mother glass substrate is inverted again, and the first substrate is cleaved along the scribe line (cutting step).

  Therefore, in conventional processing, it is necessary to invert the substrate twice, and it is necessary to form or cut a scribe line each time, so the number of processing operations and inversion operations increases, and work efficiency decreases, There was a problem that the production cost increased. In the course of the operation, there is a possibility that defects such as breakage or chipping of the mother glass substrate may occur due to vibration or the like, which has been one of the factors that reduce the yield.

  That is, in order to increase the yield or obtain a good cut surface, it is desirable that the scribing process, the cutting process, and the number of inversions of the mother glass substrate accompanying them are small. This requirement is not limited to the cutting of a mother glass substrate for a flat display, but also applies to the cutting of a general brittle material substrate.

  The present invention has been made in view of such problems, and one of its purposes is to provide a technology for processing a brittle material substrate with a reduced number of steps.

One embodiment of the present invention relates to a method for cutting a mother glass substrate of a display panel including a first glass substrate and a second glass substrate bonded together by a sealing material that partitions a plurality of cells arranged in a matrix. This method includes the following steps.
1. A processing line is arranged in the gap between the sealing materials of adjacent cells, and a laser is irradiated on the first glass substrate along the processing line to form a scribe line on the first glass substrate.
2. Along the processing line, the second glass substrate is irradiated with laser, the vicinity of the region irradiated with the laser is cooled, and the second glass substrate is cleaved.
3. The stress generated when the second glass substrate is cleaved is transmitted to the first glass substrate through the sealing material, so that the first glass substrate is cleaved along the scribe line substantially simultaneously with the cleaving of the second glass substrate. To do.

  According to this aspect, two laminated glasses can be cut by one scribing process and one break (breaking) process, the processing process can be simplified, and the yield and processing quality can be improved. .

  The depth of the scribe line formed on the first glass substrate may be in the range of 1/3 to 1/2 of the thickness of the first glass substrate. By setting the depth of the scribe line within this range, the first glass substrate can be suitably cleaved by the stress from the second glass substrate.

  It should be noted that any combination of the above-described constituent elements, and those in which constituent elements and expressions of the present invention are mutually replaced between methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to an aspect of the present invention, the number of steps can be reduced.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  The present embodiment relates to a method for cutting a liquid crystal panel. FIGS. 1A and 1B are diagrams showing a configuration of a mother glass substrate to be cut. Since the structure of the mother glass substrate 1 is general, only a brief description will be given here. 1A is a plan view of the mother glass substrate, and FIG. 1B is a cross-sectional view. The mother glass substrate 1 includes a plurality of cells 3 arranged in a matrix. As shown in FIG. 1B, the mother glass substrate 1 includes a first glass substrate G1 and a second glass substrate G2 bonded together by a sealing material 5. The sealing material 5 defines the periphery of the cell 3, and a light emitting region surrounded by the sealing material 5 is filled with a liquid crystal material 11.

  Processed lines L1 and L2 in the column direction and the row direction of the matrix are arranged in the gaps between the sealing materials 5 of the adjacent cells 3, respectively. The processing lines L1 and L2 are virtual. The cell 3 is divided into individual sides by cutting the mother glass substrate 1 along the planned processing lines L1 and L2.

  The above is the outline of the mother glass substrate 1 to be processed. Next, a method for cutting the mother glass substrate 1 according to the embodiment will be described.

  2A and 2B are diagrams illustrating a flow of the cutting method according to the embodiment. The cutting method includes a first step (FIG. 2A) and a second step (FIG. 2B) as substantial steps, and further includes a third step as an additional step thereof.

1. First Step As shown in FIG. 2A, the first glass substrate G1 is irradiated with the laser beam LB, and the mother glass substrate 1 and the laser beam LB are relatively moved in the direction of the planned processing line L1 (L2). As a result, a scribe line SL is formed on the surface of the first glass substrate G1. In FIG. 2A, the shape of the region 40 irradiated with the laser beam LB is desirably a vertically long shape having a major axis in the direction of the planned processing line L1 (L2).

2. 2nd process FIG.2 (b) shows the figure which reversed the upper and lower sides of the mother glass substrate 1 from the state of Fig.2 (a). In this state, along the planned processing line L1 (L2), the second glass substrate G2 is irradiated with the laser beam LB to be heated and expanded, and then the vicinity of the region 40 irradiated with the laser beam LB (cooling region 44). The second glass substrate G2 is cleaved by cooling by injecting the refrigerant into the glass substrate G2. In addition, when using the processing apparatus which can irradiate the laser beam LB from two directions of the upper surface and lower surface of the mother glass substrate 1, it is not necessary to invert the mother glass substrate 1 between a 1st process and a 2nd process. In FIG. 2B, the shape of the region 40 irradiated with the laser beam LB has a major axis in the direction of the planned machining line L1 (L2), but as will be described later, the planned machining line L1 (L2). ) May have a minor axis.

  Prior to the second step, that is, the step of cleaving the second glass substrate G2, a scribe line may be formed by irradiating the second glass substrate G2 with a laser along the planned processing line. By performing this pretreatment, the second glass substrate G2 can be easily cut in exchange for the demerit that the number of steps increases, and further, the processing quality, that is, the linearity and the flatness of the cut surface can be improved.

3. Third Step In the second step, the stress generated when the second glass substrate G2 is cleaved is transmitted to the first glass substrate G1 through the sealing material 5 and the liquid crystal material 11. This stress acts so as to tear the first glass substrate G1 in the direction perpendicular to the planned processing line L1 (L2). Since the scribe line SL is formed on the first glass substrate G1 in the first step, the stress is cleaved substantially simultaneously with the second glass substrate G2.

  In order to cut the mother glass substrate 1 satisfactorily, the depth d of the scribe line SL formed in the first process is an extremely important parameter. The depth d of the scribe line SL is preferably in the range of 1/3 to 1/2 of the thickness d1 of the first glass substrate G1.

  In the experiments of the present inventors, when the mother glass substrate 1 having the thicknesses d1 = 0.18 mm of the first glass substrate G1 and the second glass substrate G2 is cut, the depth of the scribe line SL is 0.09 mm, that is, the substrate If the thickness exceeds 1/2 of the thickness, the crack caused by the scribing itself grows, and it becomes impossible to break only the first glass substrate G1 and simultaneously cleave both glass substrates or to control the crack propagation. Caused inconvenience. Moreover, when the depth of the scribe line SL is 0.06 mm, that is, less than 1/3 of the substrate thickness, the strength of the first glass substrate G1 is too high, so that the first glass substrate G1 is cleaved in the third step. I can't.

  When the depth of the scribe line SL is in the range of 1/3 to 1/2 of the thickness of the first glass substrate G1, the first glass substrate G1 may be cleaved simultaneously with the second glass substrate G2 in the third step. it can. Similar findings have been obtained for other substrate thicknesses.

The effect of the cutting method according to the embodiment will become clearer by comparison with the conventional cutting method. Conventional cutting methods are generally performed through the following steps.
First step 1a. A scribe line SL is formed in the vertical direction and the horizontal direction with respect to the first glass substrate G1.
Second step 2a. Subsequently, the mother glass substrate 1 is reversed, and scribe lines are formed in the vertical direction and the horizontal direction with respect to the second glass substrate G2 on the back side.
Third step 3a. Subsequently, the second glass substrate G2 is cleaved along the scribe line.
Fourth step 4a. The mother glass substrate 1 is inverted again, and the first glass substrate G1 is cut along the scribe lines.
Therefore, the conventional processing requires two scribing steps and two cutting steps.

  On the other hand, in the cutting method according to the embodiment, the mother glass substrate 1 can be cut by one scribing process and one cutting process. Reduction in the number of processes leads to improvement in yield and reliability, and contributes to cost reduction of the liquid crystal panel.

  Further, when attention is paid to the number of inversions of the mother glass substrate 1, the number of times of reversal is one in the embodiment, compared with the number of times in the past. When the mother glass substrate 1 is inverted, there is a higher possibility that defects such as cracks and chips will occur in the mother glass substrate 1 due to vibrations, etc. However, since the number of inversions is reduced in the cutting method according to the embodiment, the occurrence of defects Can be suppressed.

  As a modification, in the cutting method according to the embodiment, the reversing process itself of the mother glass substrate 1 can be omitted. In this modification, the mother glass substrate 1 (stage) can be irradiated with a laser beam from both the upper surface and the lower surface, and a cooling mechanism is provided on at least one surface side (usually above the stage). This can be realized by using a processing device. In this case, the mother glass substrate 1 is arranged on the stage so that the first glass substrate G1 is on the upper side where the cooling mechanism is provided. In the first step, a scribe line is formed using a laser beam from the surface side (lower side) of the first glass substrate G1 of the mother glass substrate 1, and in the second step, the first glass substrate G1 is inverted. Without doing so, the second glass substrate G2 is cut using the laser beam from the surface side (upper side) of the second glass substrate G2 of the mother glass substrate 1 and the cooling mechanism.

  According to this modified example, since the reversal process of the mother glass substrate 1 is not necessary, the possibility of defects occurring in the mother glass substrate 1 can be further reduced.

Subsequently, a suitable profile of the laser beam LB in the second step will be described.
In the second step of cleaving the second glass substrate G2, the profile of the laser beam LB is substantially oval or rectangular having a minor axis in the direction of the planned processing line L1 (L2) and a major axis in the direction perpendicular to the planned processing line. It is desirable to be. More specifically, the ratio of the major axis to the minor axis is from 3: 2 to 5: 1.

  3A to 3C are diagrams showing a cutting mechanism when a horizontally long laser beam LB is irradiated. FIG. 3A shows a temperature distribution immediately after heating the laser beam LB. When a laser beam LB having a major axis in a direction perpendicular to the processing line L1 (L2) is irradiated, a wide range is heated.

  Subsequently, when the cooling medium is sprayed onto the planned processing line L1 (L2), as shown in FIG. 3B, the temperature decreases around the planned processing line L1 (L2), an impact force is generated, and the crack 45 is generated. appear. Although heat remains in a region away from the processing line L1 in the vertical direction, heat does not accumulate immediately below the crack 45. Therefore, the region 47 immediately below the crack 45 in the second glass substrate G2 is mechanical. It is in a neutral state.

  As shown in FIG. 3C, the second glass substrate G2 is cleaved as the crack 45 grows downward in the second glass substrate G2.

  If heat remains in the region 47, a compressive load is generated in the region 47, which prevents the crack 45 from growing. Such a situation can occur when heated at high intensity with a longitudinal beam profile. This is because in this case, the second glass substrate G2 is heated to a region deeper than that shown in FIG. On the other hand, when heated with a horizontally long laser beam, it is possible to suppress the generation of compressive load in the region 47, and the second glass substrate G2 can be cut well without hindering the growth of the crack 45.

FIG. 4 is a diagram showing the configuration of the irradiation optical system 16 for patterning the laser beam LB horizontally.
The irradiation optical system 16 includes a first cylindrical lens CL1 and a second cylindrical lens CL2. The first cylindrical lens CL1 and the second cylindrical lens CL2 are arranged such that the cross sections having curvatures are perpendicular to each other.

  The first cylindrical lens CL1 is an optical element that condenses the laser beam LB in a first direction (Y-axis direction) perpendicular to the propagation direction (Z-axis opposite direction). Specifically, the first cylindrical lens CL1 is a plano-convex cylindrical lens, and reduces the laser beam LB in the Y-axis direction. The curvature of the first cylindrical lens CL1 is determined according to the diameter of the original laser beam LB and the size of the laser irradiation region. As an alternative to the first cylindrical lens CL1, a concave cylindrical mirror may be used.

  The second cylindrical lens CL2 is an optical element that diverges the laser beam LB in a second direction (X-axis direction) perpendicular to the propagation direction (Z-axis opposite direction) and the first direction (Y-axis direction). . The Y axis coincides with the planned machining line L1 direction. Specifically, the second cylindrical lens CL2 is a plano-concave cylindrical lens and expands the laser beam LB in the X-axis direction. Similar to the first cylindrical lens CL1, the curvature of the second cylindrical lens CL2 is also determined according to the diameter of the original laser beam LB and the size of the laser irradiation region. As an alternative to the second cylindrical lens CL2, a convex cylindrical mirror may be used.

  The first cylindrical lens CL1 and the second cylindrical lens CL2 are arranged so that the mother glass substrate 1 side is a plane, but may be in opposite directions, and the positions of the first cylindrical lens CL1 and the second cylindrical lens CL2 are It may be replaced.

  The first cylindrical lens CL1 and the second cylindrical lens CL2 are mounted on a movable mounter, and can be moved independently in the path direction of the laser beam LB. That is, the distance between the first cylindrical lens CL1 and the mother glass substrate 1 and the distance between the second cylindrical lens CL2 and the mother glass substrate 1 can be adjusted independently. As a result, the length in the X-axis direction and the width in the Y-axis direction of the laser irradiation region 40 shown in FIG. 3A can be adjusted independently.

  When the second glass substrate G2 is cleaved using the laser beam LB shown in FIG. 2B or FIG. 4 (particularly FIG. 4), if the laser irradiation region 40 overlaps the sealing material 5, the intensity of the laser beam LB. Is too high, or when the heat resistance of the sealing material 5 is low, the sealing material 5 may be damaged. In this case, when determining the profile of the laser beam LB, the length of the laser irradiation region 40 in the direction perpendicular to the planned processing line L1 (L2) is made shorter than the interval of the sealing material 5 so that the laser irradiation region 40 It is desirable to take care not to overlap the sealant 5.

  The cells cut by the cutting method described above are assembled together with a gate driver (scan driver), a source driver (data driver), a memory, a control IC, an interface circuit, and the like into the housing of the display device to complete the display device.

  The cutting method according to the embodiment has been described above by taking the cutting of the mother glass substrate 1 of the display device as an example. However, the application range of the present invention is not limited to the cutting of the mother glass substrate 1, and can be applied to cutting of various laminated glasses used for other purposes. Furthermore, it is not limited to a glass substrate, but can be applied to other brittle material substrates.

  It will be understood by those skilled in the art that the technology disclosed in the present embodiment includes the following technical idea. That is, according to an aspect of the present invention, a method for cutting a substrate to be processed including a first brittle material substrate and a second brittle material substrate bonded together by a fixing material is provided.

  In this method, as a first step, the first brittle material substrate is irradiated with a laser along a planned processing line arranged between two fixing materials arranged apart from each other, and the first brittle material is obtained. A scribe line is formed on the substrate. Subsequently, as a second step, the second brittle material substrate is irradiated with the laser along the planned processing line, and the vicinity of the region irradiated with the laser is cooled to cleave the second brittle material substrate. The stress generated when the second brittle material substrate is cleaved in the second step is transmitted to the first brittle material substrate through the fixing material, so that the second brittle material substrate is cut substantially simultaneously with the cleaving of the second brittle material substrate. One brittle material substrate is cleaved along the scribe line.

  That is, in the embodiment, the sealing material 5 and the liquid crystal material 11 are exemplified as the fixing material. These can also be understood as utilizing the structure of the mother glass substrate 1 as an original function in the cutting method according to the present invention. From another point of view, when two brittle material substrates are cut simultaneously, the adhesive material is applied to the two regions sandwiching the planned processing line, the two brittle material substrates are bonded together, and cut according to the above procedure. May be.

  Prior to the step of cleaving the second brittle material substrate, a scribe line may be formed by irradiating the second brittle material substrate with a laser along a planned processing line. In this case, the cutting of the substrate can be assisted and the processing quality can be improved.

  Although the present invention has been described using specific words and phrases based on the embodiments, the embodiments are merely illustrative of the principles and applications of the present invention, and the embodiments are defined in the claims. Many modifications and arrangements can be made without departing from the spirit of the present invention.

FIGS. 1A and 1B are diagrams showing a configuration of a mother glass substrate to be cut. 2A and 2B are diagrams illustrating a flow of the cutting method according to the embodiment. 3A to 3C are diagrams showing a cutting mechanism when a horizontally long laser beam LB is irradiated. It is a figure which shows the structure of the irradiation optical system for patterning a laser beam horizontally long.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mother glass substrate, L1 ... Planned process line, L2 ... Planned process line, 3 ... Cell, 5 ... Sealing material, G1 ... 1st glass substrate, G2 ... 2nd glass substrate, 11 ... Liquid crystal material, 16 ... Irradiation optics System 40... Laser irradiation region 44. Cooling region CL1 First cylindrical lens CL2 Second cylindrical lens LB Laser beam

Claims (13)

A method of cutting a mother glass substrate of a display panel including a first glass substrate and a second glass substrate bonded together by a sealing material that partitions a plurality of cells arranged in a matrix,
Arranging a processing line in the gap between the sealing materials of adjacent cells, irradiating the first glass substrate with a laser along the processing line, and forming a scribe line on the first glass substrate;
Irradiating the second glass substrate with a laser along the planned processing line, cooling the vicinity of a region irradiated with the laser, and cleaving the second glass substrate;
With
The stress generated when the second glass substrate is cleaved is transmitted to the first glass substrate via the sealing material, so that the first glass substrate is substantially simultaneously with the cleaving of the second glass substrate. Cleaving along a scribe line.   2. The method according to claim 1, wherein a depth of a scribe line formed on the first glass substrate is in a range of 1/3 to 1/2 of a thickness of the first glass substrate.   In the step of cleaving the second glass substrate, the profile of the laser is a substantially oval or a substantially rectangular shape having a minor axis in the planned processing line direction and a major axis in a direction perpendicular to the planned processing line. The method according to claim 1 or 2.   The method according to claim 3, wherein the ratio of the major axis to the minor axis is from 3: 2 to 5: 1.   In the step of cleaving the second glass substrate, the profile of the laser is determined so that a region irradiated with the laser on the second glass substrate does not overlap the sealing material. The method according to claim 1.   6. The method according to claim 1, further comprising a step of irradiating a laser on the second glass substrate along the planned processing line to form a scribe line prior to the step of cleaving the second glass substrate. The method in any one of. Cutting the mother glass substrate of the display panel into cells by the method according to claim 1;
Incorporating the cut cells into a housing;
A display manufacturing method comprising: A method of cutting a substrate to be processed including a first brittle material substrate and a second brittle material substrate bonded together by a fixing material,
The first brittle material substrate is irradiated with a laser along a planned processing line arranged between two fixing materials arranged apart from each other, and a scribe line is formed on the first brittle material substrate. Steps,
Irradiating the second brittle material substrate with a laser along the planned processing line, cooling the vicinity of a region irradiated with the laser, and cleaving the second brittle material substrate;
With
The stress generated when the second brittle material substrate is cleaved is transmitted to the first brittle material substrate via the fixing material, so that substantially simultaneously with the cleaving of the second brittle material substrate, Cleaving the first brittle material substrate along the scribe line.   The depth of a scribe line formed on the first brittle material substrate is in a range of 1/3 to 1/2 of the thickness of the first brittle material substrate. Method.   9. The method according to claim 8, wherein the substrate is a mother glass substrate of a display panel, and the fixing material is a sealing material that partitions a plurality of cells.   In the step of cleaving the second brittle material substrate, the profile of the laser is approximately elliptical or approximately rectangular with a minor axis in the planned machining line direction and a major axis perpendicular to the planned machining line. 11. A method according to any one of claims 8 to 10, characterized.   The method according to claim 11, wherein a ratio of the major axis to the minor axis is 3: 2 or more and 5: 1 or less.   Prior to the step of cleaving the second brittle material substrate, the method further comprises a step of forming a scribe line by irradiating the second brittle material substrate with a laser along the planned processing line. Item 13. The method according to any one of Items 9 to 12.

Images