JP2014065629A - Dividing method and scribing device of brittle material substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply divide a thin glass substrate at low cost when divided.SOLUTION: The method for dividing a glass substrate along a predetermined division line comprises: the first step of closely placing a plurality of glass substrates on a work table; the second step of forming initial cracks in the uppermost positioned glass substrate out of the plurality of glass substrates; the third step of irradiating and heating the glass substrate having the formed initial cracks with a laser beam along the predetermined division line, cooling the heated region and forming cracks or working marks inside the plurality of substrates along the predetermined division line; and the fourth step of pressing both sides of the predetermined division line to divide the plurality of glass substrates along the predetermined division line.

Description

  The present invention relates to a method for dividing a brittle material substrate, and more particularly, to a method for dividing a brittle material substrate that divides a thin brittle material substrate along a planned division line and a scribing apparatus for carrying out the method.

For example, as a technique for dividing a glass substrate, a method of forming a scribe groove using a laser and dividing the glass substrate has been proposed. Specifically, first, for example, a CO ₂ laser is irradiated while being scanned along a planned dividing line of the glass substrate, and the glass substrate is heated to generate a compressive stress. Further, a cooling medium is blown in the vicinity where the laser beam is irradiated to cool, and tensile stress is generated in the cooling region. By the above processing, a stress gradient is formed inside the glass substrate. This stress gradient forms a crack in the glass substrate and forms a scribe groove on the substrate surface. Then, a glass substrate is parted along a parting plan line by pressing both sides of a parting plan line.

  However, in the dividing method as described above, it becomes difficult to form the scribe groove as the plate thickness of the glass substrate is reduced. This is because when the glass substrate becomes thin, an appropriate temperature distribution cannot be formed in the thickness direction during processing by laser light irradiation, and a tensile stress necessary for forming a scribe groove (crack) is generated. It is because it cannot be done.

  Moreover, in the conventional method, especially when the thickness of the glass substrate is 200 μm or less, for example, the scribe groove is not formed (half cut) but is fully cut. And when it becomes a full cut, (1) the waviness occurs in the dividing line, (2) the conditions are different depending on the position of the planned dividing line (for example, the center and the end), (3) there is a substrate size effect, (4 ) There are problems such as inability to cross-scribe.

  In view of this, as shown in Patent Document 1, there has been proposed a method in which a glass substrate as an object to be divided is fixed on a support substrate and divided. In this method, heat is transferred from the glass substrate to be divided to the support substrate, and the support substrate is distorted upwardly in the vicinity of the line to be divided.

  “Half cut” refers to a process of forming a scribe groove in a substrate by forming a crack having a depth that does not reach the back surface of the substrate. In this case, after the scribe groove is formed, the substrate can be divided by performing a dividing process of applying a bending moment by pressing the break bar along the scribe groove.

  In addition, “full cut” is a process of forming a crack reaching the substrate back surface from the substrate surface, and the substrate is divided without performing the dividing process as described above.

Republished patent WO2009 / 011246

  According to the method of Patent Document 1, the support substrate and the glass substrate as the object to be divided fixed on the support substrate can be processed as an integrated substrate. For this reason, even if it is a glass substrate with a thin thickness, similarly to the case of dividing a glass substrate with a large thickness, it is possible to realize division with excellent end face quality and excellent straightness.

  However, the method of Patent Document 1 requires a step for attaching and detaching the glass substrate to and from the support substrate every time one glass substrate is cut. For this reason, the processing time per one glass becomes long and cost becomes expensive.

  An object of the present invention is to enable easy and inexpensive division, particularly when a thin brittle material substrate is divided.

  The method for dividing a brittle material substrate according to the first aspect of the present invention is a method for dividing a brittle material substrate along a planned division line, and includes the following steps.

  First step: A step of placing a plurality of substrates in close contact and placing them on a work table.

  Second step: A step of forming an initial crack on the substrate located at the top of the plurality of substrates.

  Third step: The substrate on which the initial crack is formed is heated by irradiating the laser beam along the planned dividing line, and the heated region is cooled, and a plurality of substrates are cracked along the planned dividing line. Forming.

  Fourth step: A step of pressing the both sides of the planned dividing line and dividing the plurality of substrates along the planned dividing line.

  Here, first, a plurality of substrates are brought into close contact with each other and placed on a work table. Then, an initial crack is formed in the uppermost substrate, and thereafter, laser light is irradiated along the planned dividing line, and further, a heating region by this laser light is cooled. Thereby, cracks are formed in the plurality of substrates. In this way, by pressing both sides of the planned dividing line against the plurality of substrates in which cracks are formed along the planned dividing line, the plurality of substrates can be divided along the planned dividing line.

  Here, processing is performed with a plurality of substrates in close contact with each other, so that even when the thickness of one substrate is thin, it can be accurately divided. Further, unlike the conventional method, a supporting substrate is not necessary, and a plurality of substrates can be divided at the same time, so that the cost required for the division can be reduced.

  The brittle material substrate cutting method according to the second aspect of the present invention is the first side cutting method, wherein the plurality of substrates include a first substrate and a second substrate. The first substrate has a first thickness and is disposed on the side irradiated with the laser beam. The second substrate has a second thickness that is greater than the first thickness, and is in close contact with the first substrate.

  Here, by arranging a thinner substrate on the side irradiated with the laser light, the thin substrate can be accurately divided.

  In the method for dividing a brittle material substrate according to the third aspect of the present invention, the thickness of the first substrate is not less than 10 μm and not more than 200 μm.

  Here, when the thickness of the first substrate is less than 10 μm, the initial crack penetrates the thickness of the substrate, and there is a possibility that an unnecessary crack that does not follow the line to be divided from the initial crack may develop. Further, if the thickness of the first substrate exceeds 200 μm, it becomes difficult to propagate the crack through the first substrate to the second substrate.

  The brittle material substrate cutting method according to the fourth aspect of the present invention is the third side cutting method, wherein the thickness of the second substrate is 200 μm or more.

  Here, when the thickness of the second substrate is less than 200 μm, the compressive stress generated by heating the second substrate is small, so that the tensile stress necessary for forming the crack is sufficiently generated in the first substrate. I can't.

  The brittle material substrate cutting method according to the fifth aspect of the present invention is the cutting method according to any one of the first to fourth side surfaces, in the third step, the cutting extending along the first direction and the second direction orthogonal to each other. Cracks are formed inside the plurality of substrates along a predetermined line.

  Here, the present invention is applied to so-called cross-scribe. In particular, when cross-scribing a thin substrate, if the scribing process is executed in the first direction, the substrate is fully cut. If the scribing process is executed in the second direction when the full cut is performed, the crack stops at the full cut portion, and the scribe groove cannot be formed along the second direction.

  However, by applying the present invention, it is possible to accurately perform a cross-scribe even for a thin substrate.

  The brittle material substrate dividing method according to the sixth aspect of the present invention is the dividing method according to any one of the first to fifth aspects, wherein the plurality of substrates are brought into close contact by electrostatic discharge in the first step.

  A brittle material substrate scribing apparatus according to a seventh aspect of the present invention is a scribing apparatus for forming a crack along a planned dividing line on a brittle material substrate, and a work table for placing a plurality of substrates in close contact with each other, An initial crack formation mechanism that forms an initial crack on the substrate located at the top of the plurality of substrates, and a substrate on which the initial crack is formed is irradiated with a laser beam along a planned dividing line and heated. A laser irradiation mechanism; and a cooling mechanism that cools a region heated by the laser irradiation mechanism and forms cracks in a plurality of substrates along a predetermined dividing line.

  In the present invention as described above, when a plurality of substrates are brought into close contact with each other to form a crack in each substrate, the thin brittle material substrate can be divided easily and inexpensively.

The schematic block diagram of the apparatus for enforcing the cutting method by one Embodiment of this invention. The figure which shows typically the cross section of the glass substrate scribe-processed by the method of this invention. The photograph of the section of the glass substrate by which scribe processing was carried out by the method of the present invention. The figure which shows the range of the output and scanning speed of the laser beam which can be cut | disconnected by the method of this invention. The photograph which shows the surface state of the corner | angular part of a chip | tip at the time of cross-scribing using this invention. The photograph which shows the cross-sectional state of the corner | angular part of a chip | tip at the time of carrying out cross scribing using this invention.

[Device configuration]
FIG. 1 is a diagram showing a schematic configuration of a scribing apparatus for carrying out a method according to an embodiment of the present invention. The scribe device 1 is a device for dividing a mother glass substrate into a plurality of unit substrates used for an FPD (flat panel display), for example.

  The scribing apparatus 1 includes a table 2 on which a plurality of glass substrates G are stacked and placed, a cutter wheel 3, a laser irradiation unit 4, a cooling unit 5, a drive mechanism 6, a suction pump 7, and a control unit. 8 and. In this embodiment, an example is shown in which two glass substrates are laminated and divided. Specifically, a first glass substrate G1 having a first thickness is disposed in the upper portion, and a second glass substrate G2 having a second thickness that is thicker than the first thickness is disposed in the lower portion.

  The table 2 is formed with a plurality of through-holes 10 whose upper portions are released from the table surface. The plurality of through holes 10 are connected to the suction pump 7 via the passage 11.

  The cutter wheel 3 is a tool for forming an initial crack serving as a starting point for scribing at the end of the first glass substrate G1. This cutter wheel 3 mainly has a holder and a scribing wheel supported by the holder.

The laser irradiation unit 4 includes a laser oscillator (for example, a CO ₂ laser) that irradiates a laser beam, and irradiates the laser beam as a beam spot on the glass substrate G through an optical system. The cooling unit 5 forms a cooling spot by injecting a coolant (for example, water and air, helium gas) supplied from a coolant source (not shown) through a nozzle.

  The drive mechanism 6 is a mechanism that moves the cutter wheel 3, the laser irradiation unit 4, and the cooling unit 5 along the rail 14. By this drive mechanism 6, the cutter wheel 3, the laser irradiation unit 4, and the cooling unit 5 are moved along a scribe planned line set on the glass substrate G.

  The control unit 8 controls the cutter wheel 3, the laser irradiation unit 4, the cooling unit 5, the drive mechanism 6, and the suction pump 7. Specifically, the controller 8 controls the pressing force of the cutter wheel 3 to the glass substrate G, the laser output, the refrigerant injection amount, the driving speed (scanning speed), and the rotation speed (adsorption pressure) of the suction pump 7. The

[Division method]
First, the first and second glass substrates G1 and G2 to be processed are brought into close contact by, for example, an ESD (Electrostatic Discharge) method, and the two laminated glass substrates G are placed on the table 2. Then, the suction pump 7 is driven to suck the glass substrate G onto the table 2.

  Next, the initial crack used as the starting point of a scribe is formed in the edge part of the 1st glass substrate G1 using the cutter wheel 3. FIG.

  After the initial crack formation, the laser beam is irradiated from the laser irradiation unit 4 to the glass substrate G. This laser beam is irradiated onto the glass substrate G as a beam spot. Then, the laser beam emitted from the laser irradiation unit 4 is scanned along the planned dividing line. The glass substrate G is heated to a temperature lower than the softening point of the glass substrate G by the beam spot. Further, the cooling spot is made to follow behind the moving direction of the beam spot.

  As described above, compressive stress is generated in the vicinity of the beam spot heated by the laser beam irradiation, but a cooling spot is formed immediately after the injection of the coolant, so that it is formed on the surface of the glass substrate G. Due to the temperature difference between the cooling spot and the heating region immediately below it, a tensile stress effective for forming vertical cracks is generated in the cooling spot. Due to this tensile stress, vertical cracks along the planned dividing line are formed on the two glass substrates G1 and G2 starting from the initial crack formed at the end of the first glass substrate G1.

  In addition, when performing a cross scribe, the above process is performed along the division | segmentation planned line set to the X and Y direction orthogonal to each other.

  Thereafter, by applying a pressing force to both sides of the planned dividing line, the two glass substrates G1 and G2 are divided along the planned dividing line.

[Experimental Example 1]
Using the method of the present invention as described above, the fragmentation was verified under the following conditions.

<Glass substrate>
Plate thickness: 1st glass substrate = 0.05 mm, arranged on the upper side on the laser beam irradiation side

Second glass substrate = 0.5mm
Material: first glass substrate = non-alkali glass, linear expansion coefficient α = 3.7 × 10 ⁻⁶ / K
Second glass substrate = soda glass, linear expansion coefficient α = 8.7 × 10 ⁻⁶ / K
Size: Both 370mm x 470mm
<Laser light>
CO ₂ laser wavelength: 10.6 μm
FIG. 2 schematically shows a cross-sectional view of the substrate (before division) after performing the scribing process. FIG. 3 shows cross-sectional photographs of the scribing process start side, the center part, and the end side.

  According to this experiment, both of the two glass substrates could be hand-breaked (dividing by applying a pressing force by hand).

  As a result of cross-sectional observation, as shown in FIG. 3, the first glass substrate having a thickness of 0.05 mm is fully cut, and the second glass substrate having a thickness of 0.5 mm has a depth of about 40 μm. A crack was formed. In addition, about the scribe start side, the crack generate | occur | produced in the 1st glass substrate from the end of the initial crack, and the crack progressed. On the scribe end side, scribe (crack propagation) stopped just before the scribe end.

  FIG. 4 shows an experimental example in which the scribing process is performed by changing the laser beam output and the scanning speed. In addition, about the specification of a glass substrate, it is the same as the experimental example of FIG.2 and FIG.3. In FIG. 4, “◯” indicates that a scribe groove is formed.

  As is apparent from FIG. 4, the range in which the scribe groove can be formed is as follows.

When the laser beam output is 130 W, the scanning speed is 200 to 420 mm.
When the laser beam output is 140 W, the scanning speed is 300 to 500 mm.
When the laser beam output is 150 W, the scanning speed is 380 to 500 mm.
As the glass substrate, the thickness of the first glass substrate G1 on the side irradiated with the laser light is preferably 10 μm or more and 200 μm or less. If the thickness of the first glass substrate G1 is less than 10 μm, it cannot be divided accurately even if it is laminated, and if it is thicker than 200 μm, the second glass substrate G2 cannot be divided.

  Further, the thickness of the second glass substrate G2 is preferably 200 μm or more.

  In the above experimental example, glass substrates made of different materials are used for the first glass substrate and the second glass substrate. However, even if glass substrates made of the same material are used for the first glass substrate and the second glass substrate, Similar results to the above experiment were obtained.

[Experiment 2]
FIG. 5 shows a photograph observing the surface of the corner when cross scribing is performed. Moreover, the photograph which observed the cross section of the corner | angular part at the time of performing a cross scribe similarly in FIG. 6 is shown.

  The condition of cross scribing was that the size of one chip was 20 mm × 50 mm, the side on the 50 mm side was first scribed, and then the side on the 20 mm side was scribed. Laser irradiation conditions were executed at an output of 130 W and a scanning speed of 380 mm on the 20 mm side, and at an output of 130 W and a scanning speed of 370 mm on the 50 mm side. The specification of the glass substrate is the same as that of the first experimental example.

  As apparent from FIGS. 5 and 6, no abnormality was observed on the surface and cross section of the corner of each chip.

[Feature]
The first glass substrate G1 that cannot be accurately divided by one sheet is obtained by making the first glass substrate G1 having a small thickness and the second glass substrate G2 thicker than the first glass substrate G1 in close contact with each other to perform a scribing process and a dividing process. Can be divided accurately. Moreover, since the two glass substrates G1 and G2 can be divided at the same time, the cost required for the division can be reduced.

  When cross scribing is performed, it is possible to accurately perform cross scribing even on a thin glass substrate.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  Although the glass substrate has been described as an example in the embodiment, the object to be divided is not limited to the glass substrate, and the present invention can also be applied to the case where another brittle material substrate is divided.

DESCRIPTION OF SYMBOLS 1 Scribe device 2 Table 3 Cutter wheel 4 Laser irradiation part 5 Cooling part 6 Drive mechanism 8 Control part

Claims (7)

A cutting method for cutting a brittle material substrate along a planned cutting line,
A first step of bringing a plurality of substrates into close contact and placing them on a work table;
A second step of forming an initial crack in the uppermost substrate of the plurality of substrates;
The substrate on which the initial crack is formed is heated by irradiating a laser beam along a planned dividing line, and the heated region is cooled, and cracks or processing marks are formed inside the plurality of substrates along the planned dividing line. A third step of forming
A fourth step of pressing the both sides of the planned dividing line and dividing the plurality of substrates along the planned dividing line;
For cutting a brittle material substrate containing The plurality of substrates are:
A first substrate having a first thickness and disposed on a side irradiated with laser light;
A second substrate having a second thickness greater than the first thickness and in close contact with the first substrate;
The method for dividing a brittle material substrate according to claim 1, comprising:   The method for dividing a brittle material substrate according to claim 2, wherein the thickness of the first substrate is not less than 10 μm and not more than 200 μm.   The method for dividing a brittle material substrate according to claim 3, wherein the thickness of the second substrate is 200 μm or more.   5. The crack according to claim 1, wherein, in the third step, cracks or processing marks are formed in the plurality of substrates along a planned dividing line extending along a first direction and a second direction orthogonal to each other. Method for dividing a brittle material substrate.   The method for dividing a brittle material substrate according to any one of claims 1 to 5, wherein in the first step, the plurality of substrates are brought into close contact with each other by electrostatic discharge. A scribing device that forms a crack in a brittle material substrate along a planned cutting line,
A work table on which a plurality of substrates are placed in close contact;
An initial crack forming mechanism for forming an initial crack with respect to the substrate located at the top of the plurality of substrates;
A laser irradiation mechanism that irradiates and heats a laser beam along a division line to the substrate on which the initial crack is formed;
A cooling mechanism that cools a region heated by the laser irradiation mechanism and forms cracks in a plurality of substrates along the division line.
A brittle material substrate scribing device comprising: