KR20170013157A - Method for forming vertical crack in brittle material substrate and method for dividing brittle material substrate - Google Patents

Abstract

Provided is a method of forming a vertical crack in a brittle material substrate with high certainty. The method of forming a vertical crack in a brittle material substrate comprises: a trench line forming process of forming a trench line which is a line-shaped groove portion on a main surface; and an assistant line forming process of forming an assistant line crossing the trench line by pressing and shaking a scribing wheel which includes a blade edge having a plurality of grooves at constant intervals on an outer circumference thereof. In the trench line forming process, the trench line is formed for a part directly below the trench line not to be cracked. In the assistant line forming process, the assistant line is formed using the scribing wheel in which the plurality of grooves are asymmetric with respect to the outer circumference. The vertical crack extends from the trench line using an intersection point of both lines as a start point.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of forming a vertical crack in a brittle material substrate and a method of dividing a brittle material substrate,

The present invention relates to a method for breaking a brittle material substrate, and more particularly to a method for forming a vertical crack at the breaking of a brittle material substrate.

A manufacturing process of a flat display panel, a solar cell panel, or the like generally includes a step of dividing a substrate (mother substrate) made of a brittle material such as a glass substrate, a ceramic substrate, or a semiconductor substrate. This division includes a method of forming a scribe line by using a scribe tool such as a diamond point or a cutter wheel on the surface of the substrate and extending a crack (vertical crack) in the thickness direction of the substrate from the scribe line It is widely used. When the scribe line is formed, the vertical crack may be completely stretched in the thickness direction to divide the substrate, but the vertical crack may be partially stretched only in the thickness direction. In the latter case, after the scribe line is formed, a stress application called a break process is performed. By progressing the vertical cracks completely in the thickness direction by the breaking process, the substrate is divided along the scribe line.

As a method of extending a vertical crack by forming a scribe line, a method of forming a line-shaped processing trace which becomes a starting point (trigger) in accordance with the extension of a vertical crack, which is also called an auxiliary line, is already known (See Patent Document 1).

In addition, a cutter wheel suitable for forming a scribe line when cutting a closed curve area, such as a hole formed in a brittle material substrate, is already known (see Patent Documents 2 to 4, for example).

JP 2015-74145 A JP 2000-219527 A JPH07-223828A WO 2010087423 A

For example, in the technique using the auxiliary line as disclosed in Patent Document 1, a scribing tool such as a cutter wheel or a diamond point is imparted to the substrate during formation of the scribing line for division, It is advantageous in that the force (shock) to be applied to the object can be reduced. For example, it is possible to appropriately extend the vertical cracks from the scribe line by using the auxiliary line as a trigger, even in the form of forming the scribe line by applying a weak force (load) as the extension of the vertical crack is difficult.

However, a high yield (reliable division) is required especially for the division of the brittle material substrate in the production process of the mass product. The technique disclosed in the patent document 1 is not limited to the extension of the vertical crack starting from the auxiliary line, It does not guarantee that certainty.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method capable of forming a vertical crack with high certainty at a predetermined divided position of a brittle material substrate.

In order to solve the above problems, a first aspect of the present invention is a method of forming a vertical crack at a divided position when the brittle material substrate is divided in the thickness direction, comprising the steps of: forming, on one principal surface of the brittle material substrate, A trench line forming step of forming a trench line and a trench line forming step, and a scribing wheel having an outer peripheral portion on which a plurality of grooves are formed at equal intervals, Forming a trench line in the trench line forming step so as to maintain a crack-free state immediately below the trench line; and forming the auxiliary line forming step In the process, the plurality of grooves are formed in an asymmetrical shape with respect to the outer periphery, Using the license ice wheel forming the auxiliary line, and further characterized in that to the trench line and the intersection of the auxiliary line to the start point of a vertical crack extension from the trench line in the thickness direction of the brittle material substrate.

A second aspect of the invention is a method for forming a vertical crack in a brittle material substrate according to the first aspect, wherein in the auxiliary line forming step, in the formation of the auxiliary line, Wherein an internal crack region in which a plurality of auxiliary cracks are present is formed on the side of the auxiliary line and a formation position of the trench line and the auxiliary line is formed such that the internal crack region is formed on a side of a predetermined extension direction of a vertical crack on the trench line .

A third aspect of the present invention is a method for forming a vertical crack in a brittle material substrate according to the second aspect, wherein the auxiliary line is formed so as to intersect with the trench line in the vicinity of a side opposite to a predetermined extension direction of a vertical crack on the trench line .

The fourth aspect of the invention is a method for forming a vertical crack in the brittle material substrate according to any one of the first to third aspects, characterized in that the auxiliary line is formed after forming the trench line.

A fifth aspect of the present invention is a method for forming a vertical crack at a divided position when the brittle material substrate is divided in the thickness direction, comprising the steps of: forming a trench line for forming a trench line, And an auxiliary line forming step of forming an auxiliary line crossing the trench line by bringing a scribing wheel having peripheral edges of the peripheral edge into a plurality of grooves at regular intervals, Wherein the trench line is formed in the trench line forming step such that a crack-free state is maintained immediately below the trench line, and in the auxiliary line forming step, the plurality of trenches are formed in the left and right The scribing wheel being formed to have a different depth in the auxiliary To form a, and from the trench line to the trench line and the intersection of the auxiliary line to the start point characterized by extension a vertical crack in the thickness direction of the brittle material substrate.

A sixth aspect of the present invention is a method of dividing a brittle material substrate in a thickness direction, wherein a vertical crack is formed in the brittle material substrate by a vertical crack formation method according to any one of the first to fifth aspects, And a braking step of breaking the brittle material substrate along the vertical cracks.

According to the inventions of the first to sixth aspects, a vertical crack can be extended with high certainty at a predetermined divided position of the brittle material substrate, so that the brittle material substrate can be surely divided at the divided position.

FIG. 1 schematically shows a configuration of a scribe apparatus 100; FIG.
2 is an enlarged view of the scribing wheel 51 in the portion A;
3 is a plan view of a brittle material substrate W illustrating a state after forming the trench line TL;
4 schematically shows the configuration of the diamond point 150 used for forming the trench line TL;
5 is a partial cross-sectional view of zx including a vertical section of the trench line TL;
6 is a plan view of a brittle material substrate W illustrating the state at the time of forming the auxiliary line (AL);
FIG. 7 is a plan view of a brittle material substrate W illustrating the extension state of a vertical crack VC as a result of formation of an auxiliary line AL; FIG.
FIG. 8 is a plan view of a brittle material substrate W illustrating an extension state of a vertical crack VC as a result of formation of an auxiliary line AL; FIG.
9 is a partial cross-sectional view of zx including a vertical section of a trench line TL and a vertical crack VC;
10 is a schematic diagram showing a state in the vicinity of an auxiliary line (AL) when a vertical crack (VC) is formed;
11 is a graph plotting the VC establishment ratio with respect to the load applied at the time of forming the auxiliary line AL for each of the embodiment and the comparative example;
12 is a partially enlarged cross-sectional view of the scribing wheel 51 passing through the groove G according to the modification.

<Scribe device>

Fig. 1 schematically shows a configuration of a scribe apparatus 100 used in an embodiment of the present invention. Fig. The scribing apparatus 100 is generally used when the brittle material substrate W such as a glass substrate, a ceramics substrate, or a semiconductor substrate is divided into a small size by dividing the brittle material substrate W at a predetermined divided position in the thickness direction DT, The scribing apparatus 100 is formed in the form of an auxiliary line AL (see FIG. 6 and the like), which is formed to extend a vertical crack at a divided position on one main surface SF1 side of the brittle material substrate W . In the present embodiment, the auxiliary line AL is a trench line TL formed at a position intersecting the trench line TL (see Fig. 3, etc.) formed at the divided position on the main surface SF1 side, (Trigger) when the vertical crack is extended just below the surface of the substrate. The trench line TL is a fine line-shaped groove (concave portion) in which a vertical crack is formed immediately below the trench line TL. Details of the auxiliary line AL and the trench line TL will be described later.

The scribing apparatus 100 mainly includes a table 1 on which a brittle material substrate W is mounted and a scribe head 2 holding a scribing tool 50. [

The scribing apparatus 100 includes one or both of a table moving mechanism and a scribing head moving mechanism (not shown). By providing these mechanisms, in the scribing apparatus 100, the scribing head 2 scribes the scribing tool 50 can be moved relative to the table 1 in a horizontal plane. Hereinafter, in order to simplify the explanation, it is assumed that the scribe head 2 moves with respect to the table 1 toward the scribe direction DP shown in Fig. 1 during the scribe operation.

The scribe tool 50 is a tool for scribing the brittle material substrate W. The scribing tool 50 has a scribing wheel (cutter wheel) 51, a pin 52, and a holder 53.

The scribing wheel 51 has a disk shape (a main plate shape) and has a blade edge along its outer circumference OP. Fig. 2 is an enlarged view of the scribing wheel 51 in the part (A) shown in Fig. Fig. 2 (a) is an enlarged cross-sectional view of a portion A relating to a surface including the outer circumference OP, and Fig. 2 (b) , As viewed in a direction perpendicular to the outer periphery of the scribing wheel 51. As shown in Fig.

The outer periphery OP of the scribing wheel 51 appears to have the same circular shape as shown in Fig. 1 on a macroscopic scale. Actually, as shown in Fig. 2, on the outer periphery OP, The fine grooves G are formed at regular intervals and the gap P between adjacent grooves G forms the tip PF. That is, the scribing wheel 51 is a so-called groove forming wheel having a cutting edge PF in which the groove G and the projection P alternate. The projection P has an approximately isosceles triangular shape when viewed in cross section composed of a pair of inclined surfaces sandwiching the ridge line therebetween.

More specifically, as shown in Fig. 2 (b), the groove G is formed in an asymmetrical shape with respect to the outer periphery OP. This is realized by forming the groove G so as to be inclined with respect to the plane including the outer periphery OP. The groove G has a relatively deep portion G1 on the left and right sides of the outer periphery OP (left side than the outer periphery OP in FIG. 2 (b)) and a relatively shallow portion G2 (Rightward than the outer periphery OP in Fig. 2 (b)).

These scribing wheels 51 typically have a diameter on the order of a few millimeters. The depth of the groove G is about several 탆 to several tens of 탆 at the maximum in the portion G1 and about several 탆 at the maximum in the portion G2. Hundreds of grooves G are formed.

As the scribing wheel 51 having such a groove shape, for example, a scribe line used for forming a scribe line when cutting a closed curve area can be applied.

The pin 52 is inserted vertically into the position of the axis center AX of the scribing wheel 51. [ The holder 53 is held by the scribing head 2 and is connected to a pin (not shown) which is inserted into the scribing wheel 51 while the scribing wheel 51 is rotatable about the axis center AX 52). That is, the holder 53 rotatably supports the pin 52 and the scribing wheel 51 around the axis center AX. More specifically, in the scribing wheel 51, the portion G1 of the groove G is positioned to the right (in front of the drawing) with respect to the scribe direction DP shown in Fig. 1, and the portion G2 So as to be located on the left side (inward as viewed in the figure) with respect to the scribe direction DP. The holder 53 also horizontally supports the pin 52 so that the plane formed by the blade edge PF (outer periphery OP) of the scribing wheel 51 extends in the vertical direction.

The outer peripheral portion of the scribing wheel 51 at least where the groove G and the projection P are formed is formed using a hard material such as a hard metal, sintered diamond, polycrystalline diamond, or single crystal diamond. From the viewpoint of reducing the surface roughness of the ridgelines and the inclined surfaces, the entire scribing wheel 51 may be made of single crystal diamond.

In the scribing apparatus 100 having the above-described configuration, one main surface (hereinafter also referred to as the top surface) of the brittle material substrate W which is horizontally mounted and fixed on the table 1 with the other main surface SF2 as a mounting surface The scribe head 2 holding the scribing tool 50 is moved in the scribing direction DP while the scribing wheel 51 is in pressure contact with the scribing wheel SF1. Then, the scribing wheel 51 in a state of being in pressure contact with the brittle material substrate W moves in the direction indicated by the arrow RT in the state in which the cutting edge PF is slightly infiltrated into the brittle material substrate W AX). As a result, plastic deformation occurs in the upper surface SF1 of the brittle material substrate W in accordance with the moving direction of the scribing wheel 51 in accordance with the voltage of the scribing wheel 51. In the present embodiment, the insulation displacement operation of the scribing wheel 51 causing such plastic deformation is referred to as a scribing operation by the scribing wheel 51. [

As the scribing wheel 51 has an asymmetrical groove G with respect to the outer circumference OP as described above, the scribing wheel 51 acts on the brittle material substrate W during the scribing operation The stress is also asymmetric with respect to the scribe direction DP. Specifically, the stress acting on the right relative to the scribe direction DP where the relatively deep portion G1 of the groove G is located becomes relatively large, and the relatively shallow portion G2 of the groove G The stress acting on the left side relative to the scribe direction DP is relatively small.

The load applied to the brittle material substrate by the scribing wheel 51 when the scribing wheel 51 is brought into pressure contact with the upper surface SF1 is determined by a load adjustment And is adjustable by a mechanism.

&Lt; Order of formation of vertical cracks >

Next, the order of formation of vertical cracks at the divided positions using the auxiliary line AL in the present embodiment will be described. Figs. 3 to 9 are diagrams showing the state of formation of such a vertical crack step by step. Hereinafter, a description will be given taking as an example a case where a plurality of divided positions (dividing lines) parallel to a pair of opposite sides of the rectangular brittle material substrate W are previously set. In each drawing, the right-handed line xyz (z-axis) in which the advancing direction of the auxiliary line AL is the X-axis positive direction, the progressing direction of the trench line TL is the positive y-axis direction, Coordinates are given.

First, a trench line TL is formed. 3 is a plan view (xy plan view) of the brittle material substrate W illustrating the state after formation of the trench line TL. Fig. 4 is a view schematically showing a configuration of the scribe tool 150 used for forming the trench line TL. 5 is a zx partial cross-sectional view including a vertical section of the trench line TL. The formation position of the trench line TL shown in Fig. 3 corresponds to the division position when the brittle material substrate W is viewed from the upper surface SF1 side in a plane.

In the present embodiment, the scribe tool 150 having the diamond point 151 is used to form the trench line TL. The diamond point 151 has a truncated pyramid shape as shown in Fig. 4, for example, and has a plurality of surfaces surrounding the ceiling scene SD1 (first surface) and the ceiling scene SD1 . More specifically, as shown in Fig. 4 (b), these plural surfaces include side faces SD2 (second face) and side faces SD3 (third face). The ceiling scene SD1 and side surfaces SD2 and SD3 are oriented in different directions and are adjacent to each other. In the diamond point 151, the edge PF2 is formed by the apex PP formed by the ridge PS consisting of the side faces SD2 and SD3 and the three faces of the ceiling face SD1 and the side faces SD2 and SD3, Respectively. The diamond point 151 is held in a state where the ceiling scene SD1 is the lowermost end on one end side of a shank 152 constituting a rod (columnar) as shown in Fig. 4 (a) .

When the scribing tool 150 is used, as shown in Fig. 4 (a), the axial direction AX2 of the bag portion 152 is moved from the vertical direction toward the forward direction (y-axis normal direction) The diamond point 151 is positioned on the upper surface of the brittle material substrate W in the posture in which the ceiling surface SD1 is oriented rearward (in the y-axis direction) SF1). The edge PF2 of the diamond point 151 is slid by moving the scribing tool 150 forward in the moving direction DA while keeping the abutted state. As a result, plastic deformation along the moving direction DA of the diamond point 151 occurs. In the present embodiment, the sliding operation of the diamond point 151 causing such plastic deformation is also referred to as a scribing operation by the diamond point 151. [

3 and 5, the trench line TL is a fine line-shaped groove portion formed on the upper surface SF1 of the brittle material substrate W so as to extend in the y-axis direction. The trench line TL is formed on the upper surface SF1 of the brittle material substrate W by sliding the diamond point 151 in a state in which the posture of the scribing tool 150 is symmetrical with respect to the moving direction DA As a result of plastic deformation occurring. In this case, as schematically shown in Fig. 5, the trench line TL is formed as a trench having a line-symmetrical cross-sectional shape perpendicular to the extending direction thereof.

As shown in Fig. 3, the trench line TL is formed in the y-axis normal direction indicated by the arrow AR1 at the divided position defined by the upper surface SF1 of the brittle material substrate W, To the end point T2. Hereinafter, the range close to the viewpoint T1 in the trench line TL will be referred to as the upstream side, and the range relatively closer to the end point T2 will be referred to as the downstream side.

3, the start point T1 and the end point T2 of the trench line TL are slightly spaced apart from the ends of the brittle material substrate W. However, this is not an essential aspect, One or both of them may be appropriately positioned at the end position of the brittle material substrate W in accordance with the type of the brittle material substrate W and the use of the individual pieces after the separation. The aspect of the end of the brittle material substrate W at the point of time Tl is the same as that of the end of the scribing tool 150 as compared with the case where the point T1 is slightly distant from the end as shown in Fig. It is necessary to pay attention to the point that the life span of the blade edge PF2 and the unexpected occurrence of vertical crack occur because the impact applied to the blade edge PF2 becomes large.

The formation of the trench line TL in each of the plurality of divided positions is performed by using a scribing tool 150 in a processing device (not shown) having one scribing tool 150 Or may be formed in a manner to be formed in parallel at the same time by using a processing apparatus for forming a plurality of trench lines (TL).

A load applied by the scribing tool 150 (equivalent to a force for pushing the scribing tool 150 from above the upper surface to the upper surface SF1 of the brittle material substrate W) 5 so that the extension of the vertical crack from the trench line TL does not occur in the thickness direction DT of the brittle material substrate W although the formation of the trench line TL is surely performed (Fig. 5) .

In other words, the formation of the trench line TL is a state in which the brittle material substrate W is continuously connected in the direction intersecting the trench line TL (crack-free state) immediately below the trench line TL, . In the case where the trench line TL is formed in this correspondence, in the vicinity of the trench line TL of the brittle material substrate W (within a range of approximately 5 mu m to 10 mu m or so from the trench line TL) As a result of the deformation, the internal stress remains.

The formation of such a trench line TL is advantageous in that the load applied by the scribing tool 150 is smaller than that in the case of forming a scribing line involving the extension of vertical cracks by using the same scribing tool 150, By setting it to a small value.

Even if the trench line TL is formed, there is no extension of vertical cracks from the trench line TL, so that even if a bending moment acts on the brittle material substrate W, The breakdown along the trench line TL is less likely to occur.

Subsequent to the formation of the trench line TL, an auxiliary line AL is formed by a scribe apparatus 100 provided with a scribe tool 50. 6 is a plan view of a brittle material substrate W illustrating the state at the time of forming the auxiliary line (AL). 7 and 8 are plan views of a brittle material substrate W illustrating the extension state of a vertical crack VC as a result of the formation of the auxiliary line AL. 9 is a partial cross-sectional view of zx including a vertical section of a trench line TL and a vertical crack VC.

6, the auxiliary line AL is formed in the vicinity of the downstream side of the trench line TL in the positive X-axis direction indicated by the arrow AR2 (trench line TL, And is caused to undergo plastic deformation on the upper surface SF1 of the brittle material substrate W in the range of the starting point A1 to the end point A2.

The formation of the auxiliary line AL is performed in such a manner that the progressing direction of the auxiliary line AL indicated by the arrow AR2 is made to coincide with the scribing direction DP (X-axis normal direction). The scribing wheel 51 is moved in the scribing direction DP while the scribing wheel 51 is in pressure contact with the upper surface SF1 of the brittle material substrate W, . Then, every time the auxiliary line AL intersects with the trench line TL, a vertical crack (not shown) is generated from the position of the intersection C with each trench line TL, as indicated by the arrow AR3 in Fig. (In the case of FIG. 7, the upstream side of the trench line TL) of the brittle material substrate W from the trench line TL to the thickness direction DT of the brittle material substrate W as shown in FIG. Of the vertical crack (VC).

The formation of the auxiliary line AL is not intended to extend the vertical crack immediately below the trench line TL as in the case of forming the trench line TL, The load applied by the ice wheel 51 can be set to a smaller value than in the case of forming a scribe line involving the extension of vertical cracks by using the same scribing wheel 51. [

Finally, as shown in Fig. 8, the vertical cracks VC extend from the trench line TL at all the divided positions. That is, the formation of the auxiliary line AL becomes the trigger (the auxiliary line AL becomes the trigger), and the trench line TL is formed until the trench line TL is formed, A vertical crack VC extending from the trench line TL is formed.

This is because when the trench line TL is formed by using the scribe tool 150 having the diamond point 151, the vertical cracks VC that occur just below the trench line TL are formed in the ceiling scene SD1, Because it has the property that it is extended to the existing side. That is, the vertical crack VC generated in the vicinity of the auxiliary line AL has a property of extending in a specific direction. In the present embodiment in which the trench line TL is formed in such a manner that the ceiling scene SD1 of the diamond point is disposed on the upstream side of the trench line TL after the auxiliary line AL is formed, The vertical cracks VC are stretched in the upstream side but not in the reverse direction.

In this aspect, the brittle material substrate W on which the vertical cracks VC are formed at the dividing position is provided in a predetermined braking device (not shown). In the braking device, by applying a bending moment to the brittle material substrate W by a so-called three-point bending or four-point bending method, the vertical cracks VC extend to the lower surface SF2 of the brittle material substrate W A braking process is performed. By this breaking process, the brittle material substrate W is divided at the divided position.

In the case of the above procedure, since the formation of the trench line TL at the dividing position does not involve the extension of the vertical cracks VC, the scribing with respect to the dividing position is performed simultaneously with the formation of the scribe line, There is an advantage in that the load applied to the scribe tool 50 can be reduced. This advantage contributes to the longevity of the scribe tool 50 used for dividing at the dividing position.

<Detail of vertical crack extension>

10 is a schematic view showing a state in the vicinity of the auxiliary line AL when the vertical crack VC is formed by forming the auxiliary line AL following the formation of the trench line TL. 6 to 8 show the auxiliary line AL as roughly continuous line-shaped processing marks. However, microscopically, as shown in Fig. 10, the auxiliary line AL is formed in a groove G and the protrusions P are alternately arranged, a short line segment of the order of about 10 占 퐉 is formed as a processing trace of the pattern in which the line segments are interrupted.

If the auxiliary line AL is formed in the forward direction X of the scribing direction DP (in the direction perpendicular to the y-axis), the y-axis direction side portion 10, an internal crack region CR in which a large number of auxiliary cracks exist starting from the auxiliary line AL is formed on the side of the auxiliary line AL (lower than the auxiliary line AL in the figure) .

More specifically, the internal crack region CR occurs in a manner such that it is localized in a range from the (-y, -z) direction to the -z direction starting from an arbitrary position of the auxiliary line AL . The internal crack region CR is formed in a range from the auxiliary line AL to a maximum of about several tens of micrometers in the direction of the y axis than the auxiliary line AL when the top surface SF1 is seen from the plane.

This is considered to be related to the direction of the scribing wheel 51 when forming the auxiliary line AL. That is, when the auxiliary line AL is formed in the normal direction of the X-axis, which is the scribing direction DP, the scribing wheel 51 used for forming the auxiliary line AL has a relatively deep portion G1) is directed to the upstream side (eventually in the y-axis direction side) of the trench line TL which is the anticipated extension direction of the vertical crack (VC) and the relatively shallow portion G2 is in the opposite direction of the trench line TL (Forward in the y-axis direction). In this case, as described above, on the upstream side of the trench line TL, which is the anticipated extension direction of the vertical crack (VC) on the right side, in the scribe direction DP where the portion G1 is located Relatively large stress is applied to the surface of the substrate. Therefore, it is considered that formation of an auxiliary crack from the auxiliary line (AL) is likely to occur in the y-axis direction side portion.

Since the internal crack region CR is formed throughout the auxiliary line AL, the internal crack region CR has a high probability of occurrence in the vicinity of the portion where the auxiliary line AL intersects with the trench line TL Occurs. As described above, since the internal stress remains in the vicinity of the trench line TL, the auxiliary line is formed so that the internal crack region CR is formed on the anticipated extension direction side of the vertical crack VC of the trench line TL , The internal crack region CR is formed in the region where the residual internal stress exists, so that the residual internal stress in the vicinity of the trench line TL is released. As a result, as shown by the arrow AR4 in Fig. 10 (b), the trench line (in the present embodiment, the trench line TL in the present embodiment) Lt; RTI ID = 0.0 &gt; (VC) &lt; / RTI &gt; This is the detail of the extension of the vertical crack (VC) by the above-described technique according to the present embodiment.

Although not shown in Fig. 10, stress acts on the positive side in the y-axis direction where the relatively shallow portion G2 of the groove G is located, and the formation of the auxiliary crack occurs stochastically As a phenomenon, secondary cracks can occur. However, even if the occurrence probability is small and the portion G2 is scribed toward the anticipated extension direction of the vertical crack (VC) since the acting stress is small as compared with the side where the portion G1 is located, The reliability of the extension of the vertical crack (VC) is not increased.

Alternatively, by using a scribing wheel having a groove having a symmetrical shape with respect to the outer periphery, an aspect of forming the auxiliary line AL is also taken into consideration. In this case, the formation of the inner crack region CR is performed in the scribe direction The vertical crack VC may be isotropic with respect to the right and left sides of the vertical crack VC in consideration of the extension of the vertical crack VC in the intended extension direction of the vertical crack VC, There is no particular advantage in forming the internal crack region CR more aggressively in the case of the present embodiment. In this case also, the reliability of the extension of the vertical crack VC is not higher than that in the above-described embodiment .

As described above, according to the present embodiment, when the brittle material substrate is divided at the predetermined dividing position, the formation of the trench line under the condition that no vertical crack occurs immediately below the forming position corresponding to the dividing position And an auxiliary line is formed in such a manner that auxiliary cracks are unevenly distributed on the upstream side of the trench line, which is the anticipated extension direction of the vertical crack (VC), in which a scribing wheel made by intentionally inclining in the horizontal plane is used, Vertical cracks can be stretched with high certainty at the corresponding cut-off position. By forming the vertical crack reliably, it becomes possible to reliably separate the brittle material substrate at the divided position in the subsequent braking process. In this case, the load applied by the scribing wheel during the formation of the trench line and the auxiliary line can be set to a value smaller than that in the case of scribing operation involving extension of vertical cracks.

<Examples>

As an embodiment, the formation of the trench line TL and the auxiliary line AL by the procedure shown in the above-described embodiment is repeated a plurality of times with different formation conditions of the auxiliary line AL, and the extension of the vertical crack VC Were evaluated. As the brittle material substrate W, a 0.3 mm thick glass substrate was used.

Specifically, the auxiliary line (AL) has seven different levels of load applied to the scribing wheel (51) of 0.8 N, 1.1 N, 1.5 N, 1.9 N, 2.3 N, 2.6 N and 3.0 N . The moving speed of the scribe head 2 was set at 100 mm / sec. The diameter of the insertion hole of the pin 52 is 0.8 mm, the blade angle is 110 占 and the number of grooves G is 360 And the maximum depth of the groove (G) was 3 占 퐉.

In addition, the trench line TL is formed with 100 loads for each forming condition of the auxiliary line AL, with the load applied to the scribing tool 150 being fixed.

In addition, as a comparative example, the occurrence situation of the extension of the vertical crack (VC) was evaluated under the same conditions as those of the embodiment except that the scribing wheel in which grooves were formed symmetrically with respect to the outer periphery was used.

11 is a graph showing the rate of occurrence of extension of vertical cracks (VC) from 100 trench lines TL in the embodiment and the comparative example (hereinafter referred to as VC formation ratio) And plotted against the applied load.

As shown in Fig. 11, in the comparative example, when the load was 1.5 N or less, a VC establishment ratio of 90% or more was obtained, but the maximum value remained at 93% in the case where the load was 0.8N. On the other hand, in the example, in the comparative example, the VC establishment ratio of 95% or more, which is higher than that of the comparative example, is obtained in the load range of 1.5N or less in which 90% or more of the VC establishment ratio is obtained. When the load is 1.1N 100% VC establishment rate was achieved.

These results show that the method according to the above-described embodiment having a groove portion having an asymmetrical shape with respect to the outer periphery is suitable in terms of assuring expansion of vertical cracks.

If a scribe operation is performed using the scribing wheel 51 of the same condition to extend a vertical crack with the formation of the scribe line, it is necessary to apply a load of at least about 3 to 4N, The result of the embodiment also shows that the formation of the auxiliary line AL is performed by applying a load smaller than the load applied by the scribing wheel 51 at the scribing operation involving the extension of the vertical cracks. More specifically, the trench line TL can be formed at the same level as the formation of the auxiliary line AL or at the application of a smaller load. Therefore, the method according to the above- It is also possible to say that it is possible to allow the extension of the vertical crack to be caused by the application of the lowering force.

&Lt; Modifications and Reference Examples >

Although the auxiliary line AL is formed after forming the trench line TL in the above-described embodiment, the order of forming the trench line TL and the auxiliary line AL may be reversed.

In the embodiment described above, the trench line TL and the auxiliary line AL are orthogonal to each other on the upper surface SF1 of the brittle material substrate W. However, this is not an essential aspect, The trench line TL and the auxiliary line AL may be in an obliquely intersecting manner as long as the extension of the vertical crack from the trench line TL in accordance with the formation of the trench line TL is appropriately realized.

In the above-described embodiment, the scribing tool 150 forms the trench line TL in a state in which the axial direction AX2 of the bag portion 152 is inclined forward in the moving direction DA, The axle direction AX2 of the bag portion 152 is set to be smaller than the axial direction AX2 of the bag portion 152. In this case, The trench line TL is formed by sliding the diamond point 151 in a posture in which the ceiling scene SD1 is oriented toward the front of the moving direction DA in a state of inclining toward the rear of the moving direction DA You can.

Alternatively, in the above-described embodiment, the diamond point 151 is used to form the trench line TL, but instead of this, the trench line TL may be formed by rolling the scribing wheel do. In this case, it is preferable to use a scraping wheel having no groove formed at the blade edge.

However, in the latter two cases, unlike the above-described embodiment, the predicting direction of the vertical crack is the downstream side of the trench line TL. Therefore, in these aspects, the scribing wheel 51 is disposed such that the relatively deep portion G1 of the groove G faces the downstream side of the trench line TL, and the scribing wheel 51 is located upstream of the trench line TL The auxiliary line (AL) is formed in the vicinity of the auxiliary line (AL).

In this case also, the auxiliary line AL is formed in such a manner that the auxiliary crack AC is unevenly distributed on the downstream side of the trench line TL, which is the predicting direction of the vertical crack VC, as in the above- , Vertical cracks are appropriately extended from the trench line TL in the anticipated extension direction of the vertical cracks VC. As a result, a vertical crack can be extended with high certainty at the division position where the trench line TL is formed.

The formation of the groove G in the scribing wheel 51 is not limited to that shown in the above-described embodiment. If an internal crack region in which a plurality of auxiliary cracks are unevenly distributed on one side of the side of the auxiliary line can be generated, for example, as disclosed in Patent Document 2, a variety of asymmetrical shapes with respect to the outer circumference OP May be employed.

12 is a partially enlarged cross-sectional view of the scribing wheel 51 passing through the groove G according to the modified example. In the above-described embodiment, it is said that the scribing wheel 51 (more specifically, the projection P) is formed in a substantially isosceles triangle shape as viewed from a cross section formed by a pair of inclined surfaces sandwiching the ridge line However, as the scribing wheel 51 in which a plurality of auxiliary cracks are unevenly distributed on one side of the side of the auxiliary line, the angle? 1,? 2 with respect to the outer circumference OP A scribing wheel 51 having two different inclined surfaces may be used.

1: Table 2: Scribe head
50, 150: scribe tool 51: scribing wheel
52: pin 53: holder
100: scribe device 151: diamond point
152: Bag portion A1: (at the time of the auxiliary line (TL))
A2: (of auxiliary line (TL)) End point AL: auxiliary line
AX: Axis center
C: (intersection of trench line (TL) and auxiliary line (AL))
CR: internal crack area DP: scribe direction
G: Groove (of the scribing wheel 51) OP: Outer (of the scribing wheel 51)
P: the projection PF (of the scribing wheel 51)
One main surface (upper surface) of SF1 (of the brittle material substrate W)
SF2 (of the brittle material substrate W) on the other main surface (lower surface)
T1: (at the trench line (TL)) T2: end point (at the trench line (TL)
TL: Trench line VC: Vertical crack
W: brittle material substrate

Claims (6)

As a method of forming a vertical crack at a divided position when the brittle material substrate is divided in the thickness direction,
A trench line forming step of forming a trench line, which is a line-shaped groove, on one principal surface of the brittle material substrate;
An auxiliary line forming step of forming a subsidiary line crossing the trench line by bringing a scribing wheel having peripheral edges of a plurality of grooves formed at equal intervals into contact with each other on the one main surface, ,
In the trench line forming step, the trench line is formed so that a crack-free state is maintained immediately below the trench line,
In the auxiliary line forming step, the auxiliary line is formed by using the scribing wheel in which the plurality of grooves are formed in an asymmetrical shape with respect to the outer periphery,
And forming a vertical crack in the brittle material substrate in the thickness direction of the brittle material substrate from the trench line with an intersection of the trench line and the auxiliary line as a starting point. . 2. The method according to claim 1, wherein, in the auxiliary line forming step, an internal crack area in which a plurality of auxiliary cracks exist in the side of the auxiliary line in the brittle material substrate is formed in accordance with formation of the auxiliary line ,
Wherein the formation position of the trench line and the auxiliary line is determined so that the internal crack region is formed on a side of a predetermined extension direction of a vertical crack on the trench line. The method of forming a vertical crack in a brittle material substrate according to claim 2, wherein the auxiliary line is formed so as to intersect with the trench line in the vicinity of a side opposite to a predetermined extension direction of a vertical crack on the trench line. 4. A method according to any one of claims 1 to 3, wherein the auxiliary line is formed after forming the trench line. As a method of forming a vertical crack at a divided position when the brittle material substrate is divided in the thickness direction,
A trench line forming step of forming a trench line, which is a line-shaped groove, on one principal surface of the brittle material substrate;
An auxiliary line forming step of forming a subsidiary line crossing the trench line by bringing a scribing wheel having peripheral edges of a plurality of grooves formed at equal intervals into contact with each other on the one main surface, ,
In the trench line forming step, the trench line is formed so that a crack-free state is maintained immediately below the trench line,
In the auxiliary line forming step, the auxiliary line is formed by using the scribing wheel formed so that the plurality of grooves have different depths on the right and left sides of the outer periphery,
And a vertical crack is caused to extend from the trench line in the thickness direction of the brittle material substrate with an intersection of the trench line and the auxiliary line as a starting point. As a method of dividing the brittle material substrate in the thickness direction,
A vertical crack forming step of forming a vertical crack in the brittle material substrate by the method of forming a vertical crack according to claim 1 or 5,
And braking the brittle material substrate along the vertical crack to break the brittle material substrate.

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