JP2017024349A - Method for formation of vertical crack in brittle material substrate and method for segmentation of brittle material substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which can form a vertical crack in a brittle material substrate with high reliability.SOLUTION: A method for formation of a vertical crack in a brittle material substrate comprises: a trench line formation process in which a trench line which is a line-shaped groove part is formed on one principal plane; an assist line formation process in which an assist line crossing the trench line is formed by pressure-welding rolling a scribing wheel which includes, on an outer peripheral part thereof, a tip provided with plural grooves at equal intervals. In the trench line formation process, a trench line is so formed that a crackless state is maintained just thereunder, and in the assist line formation process, an assist line is formed by use of a scribing wheel on which plural grooves are formed in an asymmetrical shape with respect to an outer periphery, and thereby extension of a vertical crack from a trench line is generated with an intersection point of both lines as an initiation point.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for dividing a brittle material substrate, and more particularly to a method for forming a vertical crack when dividing a brittle material substrate.

  A manufacturing process of a flat display panel or a solar cell panel 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. For such cutting, a technique is widely used in which a scribe line is formed on the substrate surface using a scribe tool such as a diamond point or a cutter wheel, and a crack (vertical crack) is extended from the scribe line in the thickness direction of the substrate. Yes. When the scribe line is formed, the vertical crack may be completely extended in the thickness direction and the substrate may be divided, but the vertical crack may be only partially extended in the thickness direction. In the latter case, after the scribe line is formed, stress is applied which is called a break process. The substrate is divided along the scribe line by causing the vertical crack to advance completely in the thickness direction by the break process.

  As a technique for extending a vertical crack by forming a scribe line, a technique for forming a linear processing trace, which is also referred to as an assist line, and serves as a starting point (trigger) in extending a vertical crack is already known. (For example, refer to Patent Document 1).

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

Japanese Patent Application Laid-Open No. 2015-74145 JP 2000-219527 A Japanese Patent Application Laid-Open No. 07-223828 International Publication No. 2010/087423

  For example, a technique using an assist line as disclosed in Patent Document 1 is different from a technique not using this in that a scribe tool such as a cutter wheel or a diamond point is formed on a substrate when forming a scribe line for cutting. There is an advantage that the applied force (impact) can be reduced. For example, even if the scribe line is formed by applying a weak force (load) that makes it difficult to extend the vertical crack, the vertical crack can be suitably extended from the scribe line using the assist line as a trigger. is there.

  However, a high yield (reliable division) is required especially in the division of the brittle material substrate made in the production process of the mass-produced product. However, the technique disclosed in Patent Document 1 does not necessarily generate the vertical crack starting from the assist line. There is no guarantee of certainty about the extension.

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

  In order to solve the above-mentioned problem, the invention of claim 1 is a method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction, and has a linear shape on one main surface of the brittle material substrate. A trench line forming step for forming a trench line which is a groove portion, and a scribing wheel having a blade edge provided with a plurality of grooves at equal intervals on the outer peripheral portion is pressed and rolled on the one main surface to intersect the trench line. An assist line forming step for forming an assist line that is a processing mark, and in the trench line forming step, the trench line is formed so that a crackless state is maintained immediately below the trench line, and the assist line is formed. In the line forming step, the plurality of grooves are formed in an asymmetric shape with respect to the outer periphery. The assist line is formed using the scribing wheel, and a vertical crack is extended from the trench line in the thickness direction of the brittle material substrate, starting from an intersection of the trench line and the assist line. .

  The invention according to claim 2 is the method for forming vertical cracks in the brittle material substrate according to claim 1, wherein in the assist line forming step, the assist line is formed inside the brittle material substrate. An internal crack region in which a large number of assist cracks exist on the side of the assist line, and the internal crack region is formed on a predetermined extension direction side of the vertical crack on the trench line. And defining a position where the assist line is formed.

  A third aspect of the invention is a method for forming a vertical crack in a brittle material substrate according to the second aspect, wherein the assist line is arranged near the trench line in the vicinity of the opposite side of the vertical extension direction of the vertical crack on the trench line. It forms so that it may cross | intersect.

  A fourth aspect of the invention is a method for forming a vertical crack in a brittle material substrate according to any one of the first to third aspects, wherein the assist line is formed after the trench line is formed. And

  The invention according to claim 5 is a method of forming a vertical crack at a dividing position when dividing the brittle material substrate in the thickness direction, and forming a trench line which is a line-shaped groove portion on one main surface of the brittle material substrate. An assist line which is a processing trace intersecting with the trench line by pressing and rolling on the one main surface a scribing wheel having a cutting edge provided with a plurality of grooves at equal intervals on the outer peripheral portion. Forming an assist line, and forming the trench line so that a crackless state is maintained immediately below the trench line in the trench line forming process, and in the assist line forming process, The scoop formed such that a plurality of grooves have different depths on the left and right sides of the outer periphery. The assist line is formed by using Lee Bing wheel, said to extend the vertical crack in the thickness direction of the brittle material substrate from the trench line intersection of the trench line and the assist line as a starting point, and wherein the.

  The invention according to claim 6 is a method of dividing the brittle material substrate in the thickness direction, and the vertical crack is formed in the brittle material substrate by the vertical crack forming method according to any one of claims 1 to 5. It is characterized by comprising a vertical crack forming step and a break step for breaking the brittle material substrate along the vertical crack.

  According to the first to sixth aspects of the present invention, since the vertical crack can be extended with high certainty at a predetermined cutting position of the brittle material substrate, the brittle material substrate is reliably cut at the cutting position. It becomes possible to do.

1 is a diagram schematically showing a configuration of a scribe device 100. FIG. 2 is an enlarged view of a scribing wheel 51 in a portion A. FIG. It is a top view of the brittle material substrate W illustrating the state after the formation of the trench line TL. It is a figure which shows schematically the structure of the diamond point 150 used for formation of trench line TL. It is zx partial sectional drawing containing the vertical cross section of trench line TL. It is a top view of the brittle material substrate W illustrating the state when the assist line AL is formed. 4 is a top view of a brittle material substrate W illustrating how a vertical crack VC extends along with the formation of an assist line AL. FIG. 4 is a top view of a brittle material substrate W illustrating how a vertical crack VC extends along with the formation of an assist line AL. FIG. It is zx partial sectional drawing containing the vertical cross section of trench line TL and the vertical crack VC. It is a schematic diagram which shows the mode of the assist line AL vicinity at the time of the vertical crack VC being formed. It is the graph which plotted VC establishment rate with respect to the load applied at the time of formation of assist line AL about each of an Example and a comparative example. It is a partial expanded sectional view which passes along the groove | channel G of the scribing wheel 51 which concerns on a modification.

<Scribe device>
FIG. 1 is a diagram schematically showing a configuration of a scribing apparatus 100 used in the embodiment of the present invention. The scribing device 100 is generally used when a brittle material substrate W such as a glass substrate, a ceramic substrate, or a semiconductor substrate is divided in the thickness direction DT at a predetermined dividing position to reduce the size. In the embodiment, the scribing apparatus 100 is used for forming an assist line AL (see FIG. 6 and the like) that is performed to extend a vertical crack at a dividing position on the one main surface SF1 side of the brittle material substrate W. In the present embodiment, the assist line AL is perpendicular to the trench line TL that is formed at a position intersecting with the trench line TL (see FIG. 3 and the like) formed at the dividing position on the main surface SF1 side. It is a processing mark that becomes a starting point (trigger) when a crack is extended. Further, the trench line TL is a fine line-shaped groove (concave portion) immediately below the trench crack TL. Details of the assist line AL and the trench line TL will be described later.

  The scribing apparatus 100 mainly includes a table 1 on which the brittle material substrate W is placed and a scribing head 2 that holds the scribing tool 50.

  The scribing apparatus 100 includes one or both of a table moving mechanism and a scribing head moving mechanism (not shown). With these mechanisms, in the scribing apparatus 100, the scribing head 2 holds the scribing tool 50. The table 1 can move relative to the horizontal plane. Hereinafter, for the sake of simplicity, it is assumed that the scribe head 2 moves relative to the table 1 in the scribe direction DP shown in FIG.

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

  The scribing wheel 51 has a disc shape (an abacus bead shape), and has a cutting edge along its outer periphery OP. FIG. 2 is an enlarged view of the scribing wheel 51 in the portion A shown in FIG. FIG. 2A is an enlarged cross-sectional view of the portion A with respect to the surface including the outer periphery OP, and FIG. 2B shows a further portion of the portion A on the outer periphery of the scribing wheel 51 indicated by an arrow B. It is the figure seen from the perpendicular direction.

  Macroscopically, the outer periphery OP of the scribing wheel 51 appears to be a uniform circle as shown in FIG. 1, but in practice, as shown in FIG. The fine groove | channel G is provided at equal intervals, and between the adjacent groove | channels G becomes the processus | protrusion P, and the blade edge | tip PF is comprised. That is, the scribing wheel 51 is a so-called grooved wheel having a cutting edge PF in which grooves G and protrusions P are alternately present. The protrusion P has a substantially isosceles triangle shape in cross-sectional view, which includes a ridge line and a pair of inclined surfaces sandwiching the ridge line.

  More specifically, as shown in FIG. 2B, the groove G is provided in an asymmetric shape with respect to the outer periphery OP. This is realized by providing the groove G so as to be inclined with respect to the surface including the outer periphery OP. Accordingly, the groove G has a relatively deep portion G1 (left side of the outer periphery OP in FIG. 2B) and a relatively shallow portion G2 (the outer periphery of FIG. 2B) on the left and right sides of the outer periphery OP. And the right side of the OP).

  Such a scribing wheel 51 typically has a diameter of several millimeters. The depth of the groove G is about several μm to several tens of μm at maximum in the portion G1, and about several μm at maximum in the portion G2. About several hundreds of grooves G are provided.

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

  The pin 52 is inserted perpendicularly to the position of the axis center AX of the scribing wheel 51. The holder 53 is held by the scribe head 2 and supports a pin 52 inserted through the scribing wheel 51 in such a manner that the scribing wheel 51 can rotate around the axial center AX. That is, the holder 53 pivotally supports the pin 52 and the scribing wheel 51 so as to be rotatable around the axis center AX. More specifically, in the scribing wheel 51, the portion G1 of the groove G is located on the right side (the front side in the drawing) with respect to the scribe direction DP shown in FIG. It is pivotally supported so that it is located on the back side. The holder 53 supports the pin 52 horizontally so that the surface formed by the cutting edge PF (outer periphery OP) of the scribing wheel 51 extends in the vertical direction.

  Of the scribing wheel 51, at least the vicinity of the outer periphery where the groove G and the protrusion P are provided is formed using a hard material such as cemented carbide, sintered diamond, polycrystalline diamond or single crystal diamond. . From the viewpoint of reducing the surface roughness of the ridgeline and the inclined surface, 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 an upper surface) of the brittle material substrate W that is horizontally mounted and fixed on the table 1 with the other main surface SF2 as a mounting surface. The scribing head 2 that holds the scribing tool 50 is moved in the scribing direction DP while the scribing wheel 51 is in pressure contact with SF1. Then, the scribing wheel 51 in pressure contact with the brittle material substrate W is rolled around the axis center AX in the direction indicated by the arrow RT in a state where the cutting edge PF is slightly intruded into the brittle material substrate W. Thereby, on the upper surface SF <b> 1 of the brittle material substrate W, plastic deformation along the moving direction of the scribing wheel 51 occurs with the press-contact rolling of the scribing wheel 51. In the present embodiment, the pressure rolling operation of the scribing wheel 51 that causes the plastic deformation is referred to as a scribing operation by the scribing wheel 51.

  As described above, the stress that the scribing wheel 51 acts on the brittle material substrate W during the scribing operation due to the asymmetric groove G with respect to the outer periphery OP as described above is also applied to the scribing direction DP. It is asymmetric. Specifically, the stress acting on the right side with respect to the scribe direction DP in which the relatively deep portion G1 of the groove G is located is relatively large, and the relatively shallow portion G2 of the groove G is located. The stress acting on the left side with respect to the scribe direction DP becomes relatively small.

  The load applied to the brittle material substrate by the scribing wheel 51 when the scribing wheel 51 is pressed against the upper surface SF1 can be adjusted by a load adjusting mechanism (not shown) provided in the scribe head 2.

<Vertical crack formation procedure>
Next, a procedure for forming a vertical crack at the dividing position using the assist line AL performed in the present embodiment will be described. FIG. 3 to FIG. 9 are diagrams showing stepwise how the vertical crack is formed. Hereinafter, the case where a plurality of cutting positions (cutting lines) parallel to a pair of opposite sides are set in advance with respect to the rectangular brittle material substrate W will be described as an example. Also, in each figure, the right-handed xyz coordinates in which the formation progress direction of the assist line AL is the x-axis positive direction, the formation progress direction of the trench line TL is the y-axis positive direction, and the upper vertical direction is the z-axis positive direction. It is attached.

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

  In the present embodiment, a scribe tool 150 having a diamond point 151 is used for forming the trench line TL. The diamond point 151 has a truncated pyramid shape, for example, as shown in FIG. 4, and is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. More specifically, as shown in FIG. 4B, these plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1 and the side surfaces SD2 and SD3 face different directions and are adjacent to each other. At the diamond point 151, the cutting edge PF2 is formed by the ridgeline PS formed by the side surfaces SD2 and SD3 and the vertex PP formed by the three surfaces of the top surface SD1, the side surfaces SD2 and SD3. As shown in FIG. 4A, the diamond point 151 is held on the one end side of the shank 152 having a rod shape (columnar shape) in such a manner that the top surface SD1 is the lowest end portion.

  When the scribe tool 150 is used, as shown in FIG. 4A, the axial direction AX2 of the shank 152 is inclined by a predetermined angle from the vertical direction toward the front of the moving direction DA (positive direction of the y-axis). In this state, that is, with the top surface SD1 facing backward in the movement direction DA (y-axis negative direction), the diamond point 151 is brought into contact with the upper surface SF1 of the brittle material substrate W. Then, the cutting edge PF2 of the diamond point 151 is slid by moving the scribe tool 150 forward in the moving direction DA while maintaining such a contact 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 that causes such plastic deformation is also referred to as a scribe operation by the diamond point 151.

  As shown in FIGS. 3 and 5, the trench line TL is a fine line-shaped groove 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 as a result of plastic deformation occurring in the upper surface SF1 of the brittle material substrate W by sliding the diamond point 151 in a state where the posture of the scribe tool 150 is symmetric with respect to the moving direction DA. . In such a case, as schematically shown in FIG. 5, the trench line TL is generally formed as a groove having a line-symmetric shape in a cross section perpendicular to the extending direction.

  As shown in FIG. 3, the trench line TL is formed from the start point T1 to the end point T2 in the positive y-axis direction indicated by the arrow AR1 at the dividing position defined on the upper surface SF1 of the brittle material substrate W. Hereinafter, a range relatively close to the start point T1 in the trench line TL is also referred to as an upstream side, and a range relatively close to the end point T2 is also referred to as a downstream side.

  In FIG. 3, the start point T1 and the end point T2 of the trench line TL are positioned slightly separated from the end of the brittle material substrate W, but this is not an essential aspect, and the brittleness to be divided Either one or both of them may be the end position of the brittle material substrate W depending on the type of the material substrate W, the use of the separated pieces, or the like. However, the mode in which the start point T1 is the end of the brittle material substrate W is formed on the cutting edge PF2 of the scribe tool 150 as compared to the case where the start point T1 is a position slightly separated from the end as illustrated in FIG. Since the applied impact is increased, attention should be paid from the viewpoint of the life of the blade edge PF2 and the occurrence of unexpected vertical cracks.

  In addition, the formation of the trench line TL at each of the plurality of dividing positions may be an embodiment in which the trench line TL is sequentially formed by using the scribe tool 150 in a processing apparatus (not shown) provided with one scribe tool 150. It may be formed in parallel using a processing apparatus for forming the line TL.

  When the trench line TL is formed, the load applied by the scribe tool 150 (corresponding to a force for pushing the scribe tool 150 from the vertically upward to the upper surface SF1 of the brittle material substrate W) is surely formed. However, it is set 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 (FIG. 5).

  In other words, the formation of the trench line TL is performed so that the brittle material substrate W is continuously connected in the direction intersecting the trench line TL (a crackless state) immediately below the trench line TL. When the trench line TL is formed in such a manner, internal stress remains as a result of plastic deformation in the vicinity of the trench line TL of the brittle material substrate W (in a range within about 5 μm to 10 μm from the trench line TL). To do.

  For example, the trench line TL is formed by setting the load applied by the scribe tool 150 to a smaller value than when forming the scribe line accompanied by the extension of the vertical crack using the same scribe tool 150. Realized.

  In the crackless state, even if the trench line TL is formed, the vertical crack does not extend from the trench line TL. Therefore, even if a bending moment acts on the brittle material substrate W, the vertical crack is formed. As compared with the case where it is formed, the division along the trench line TL is less likely to occur.

  Following the formation of the trench line TL, the assist line AL is formed by the scribe device 100 including the scribe tool 50. FIG. 6 is a top view of the brittle material substrate W illustrating the state when the assist line AL is formed. 7 and 8 are top views of the brittle material substrate W illustrating the extension of the vertical crack VC accompanying the formation of the assist line AL. FIG. 9 is a zx partial cross-sectional view including a vertical cross section of the trench line TL and the vertical crack VC.

  In the present embodiment, as shown in FIG. 6, the assist line AL has a start point A1 in the positive x-axis direction indicated by an arrow AR2 (so as to be orthogonal to the trench line TL) in the vicinity of the downstream side of the trench line TL. To the end point A2 is a processing mark formed by causing plastic deformation on the upper surface SF1 of the brittle material substrate W.

  The assist line AL is formed in such a manner that the direction in which the assist line AL is formed as indicated by the arrow AR2 coincides with the scribe direction DP (x-axis positive direction). That is, the scribing wheel 51 is rolled by moving the scribing head 2 in the scribing direction DP in a state where the scribing wheel 51 is in pressure contact with the upper surface SF1 of the brittle material substrate W. Then, every time the assist line AL intersects the trench line TL, as indicated by an arrow AR3 in FIG. 7, the planned extension direction of the vertical crack VC from the position of the intersection C with each trench line TL (in the case of FIG. 7) If so, the vertical crack VC extends from the trench line TL in the thickness direction DT of the brittle material substrate W as shown in FIG. 9 sequentially toward the upstream side of the trench line TL.

  Note that the assist line AL is not formed for the purpose of extending the vertical crack immediately below the trench line TL as in the case of forming the trench line TL. The applied load can also be set to a smaller value as compared to the case where the same scribing wheel 51 is used to form a scribe line with vertical crack extension.

  Eventually, as shown in FIG. 8, the extension of the vertical crack VC from the trench line TL occurs at all the dividing positions. That is, triggered by the formation of the assist line AL (triggered by the assist line AL), until the trench line TL has been formed, the crack-less state of each of the brittle material substrates W has been divided. A vertical crack VC extending from the trench line TL is formed.

  This is because when the scribe tool 150 having the diamond point 151 is used to form the trench line TL, the vertical crack VC generated immediately below the trench line TL has a property of extending to the side where the top surface SD1 exists. is there. That is, the vertical crack VC generated in the vicinity of the assist 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 top surface SD1 of the diamond point is disposed on the upstream side of the trench line TL, after the assist line AL is formed, it is vertical on the upstream side of the trench line TL. Although the crack VC extends, it is difficult to extend in the reverse direction.

  In this manner, the brittle material substrate W on which the vertical crack VC is formed at the dividing position is given to a predetermined break device (not shown). In the break device, a break process for extending the vertical crack VC to the lower surface SF2 of the brittle material substrate W is performed by applying a bending moment to the brittle material substrate W by a so-called three-point bending or four-point bending method. . By passing through the break process, the brittle material substrate W is divided at the dividing position.

  In the case of the above procedure, since the formation of the trench line TL at the dividing position is not accompanied by the extension of the vertical crack VC, the vertical crack is formed at the same time as the scribe line is formed. There is an advantage that the load applied to the scribe tool 50 can be reduced as compared with the case where it is performed. Such an advantage contributes to extending the life of the scribe tool 50 used for cutting at the cutting position.

<Details of vertical crack extension>
FIG. 10 is a schematic diagram showing a state in the vicinity of the assist line AL when the vertical crack VC is formed by forming the assist line AL following the formation of the trench line TL. 6 to 8, the assist line AL is illustrated as a substantially continuous linear processing mark. However, microscopically, as shown in FIG. Reflecting the shape of the cutting edge PF in which the protrusions P and the protrusions P are alternately present, the line is formed as a machining trace having a short line segment of about a dozen μm.

  When the assist line AL is formed in the scribe direction DP in the x-axis positive direction (in the direction perpendicular to the y-axis), the y-axis direction negative side (FIG. 10) is formed inside the brittle material substrate W throughout the formation position. In FIG. 2, an internal crack region CR in which innumerable assist cracks starting from the assist line AL exist is formed on the side of the assist line AL (on the lower side in the drawing than the assist line AL).

  More specifically, the internal crack region CR is generated in an unevenly distributed manner within a range from the (−y, −z) direction to the −z direction starting from an arbitrary position of the assist line AL. The internal crack region CR is formed in a range of about several tens of μm at most from the assist line AL in the negative y-axis direction from the assist line AL when the upper surface SF1 is viewed in plan.

  This is considered to be related to the direction of the scribing wheel 51 when the assist line AL is formed. That is, when the assist line AL is formed in the positive x-axis direction, which is the scribe direction DP, the scribing wheel 51 used for forming the assist line AL has a relatively deep portion G1 in the groove G in the planned extension direction of the vertical crack VC. In such a posture that it faces the upstream side of the trench line TL (that is, the negative side in the y-axis direction) and the relatively shallow portion G2 faces the downstream side (the positive side in the y-axis direction) of the trench line TL that is the opposite direction. , Rolled. In this case, as described above, relative to the right side with respect to the scribe direction DP where the portion G1 is located, that is, on the upstream side (the negative side in the y-axis direction) of the trench line TL that is the expected extension direction of the vertical crack VC. Large stress acts. For this reason, it is considered that assist cracks are easily formed from the assist line AL on the negative side in the y-axis direction.

  Since the internal crack region CR is formed over the entire assist line AL, the internal crack region CR is generated with a high probability even in the vicinity of the location where the assist line AL intersects the trench line TL. As described above, since internal stress remains in the vicinity of the trench line TL, the assist line is formed so that the internal crack region CR is formed on the side of the vertical extension VC of the trench line TL in the predetermined extension direction. In this case, the internal crack region CR is formed in the region where the residual internal stress exists, and the residual internal stress is released in the vicinity of the trench line TL. As a result, as indicated by an arrow AR4 in FIG. 10B, the vertical crack from the trench line TL toward the expected extension direction of the vertical crack VC (upstream of the trench line TL in the present embodiment). VC stretching occurs. This is the details of the extension of the vertical crack VC by the method according to this embodiment described above.

  Although not shown in FIG. 10, the stress is also acting 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 assist cracks is probabilistic. Since this is a phenomenon that occurs, assist cracks can occur. However, since the acting stress is smaller than the side where the portion G1 is located, the probability of occurrence is small, and even if the portion G2 is scribed in the expected extension direction of the vertical crack VC, the above-described embodiment Compared with the method in, the certainty of extension of the vertical crack VC is not increased.

  Alternatively, an aspect in which the assist line AL is formed by using a scribing wheel having a symmetric shape with respect to the outer periphery is also conceivable. In this case, the internal crack region CR is formed on the left and right sides of the scribe direction DP. In contrast to the intended extension of the vertical crack VC in the intended extension direction of the vertical crack VC, the inner side is more positive on the side opposite to the expected extension direction of the vertical crack VC. Since there is no particular merit in forming the crack region CR, in this case as well, the certainty of extension of the vertical crack VC is not increased as compared with the method in the present embodiment described above.

  As described above, according to the present embodiment, when the brittle material substrate is divided at a predetermined dividing position, the vertical crack is not generated immediately below the forming position corresponding to the dividing position. Of the assist line in a mode in which the assist crack is unevenly distributed on the upstream side of the trench line, which is the planned extension direction of the vertical crack VC, using a scribing wheel intentionally inclined in a horizontal plane. By performing the formation, the vertical crack can be extended with high certainty at the dividing position. When the vertical crack is reliably formed, the brittle material substrate can be reliably cut at the cutting position in a break process as a subsequent process. In such a case, the load applied by the scribing wheel when forming the trench line and the assist line can be set to a value smaller than that in the case of performing a scribe operation accompanied by vertical crack extension.

<Example>
As an example, formation of the trench line TL and the assist line AL according to the procedure described in the above-described embodiment was performed a plurality of times while changing the formation conditions of the assist line AL, and the occurrence of the vertical crack VC was evaluated. . As the brittle material substrate W, a glass substrate having a thickness of 0.3 mm was used.

  Specifically, the assist line AL is different from the load applied to the scribing wheel 51 in seven levels of 0.8N, 1.1N, 1.5N, 1.9N, 2.3N, 2.6N, and 3.0N. Formed. The moving speed of the scribe head 2 was 100 mm / sec. As the scribing wheel 51, the wheel diameter is 2.0 mm, the thickness is 0.65 mm, the diameter of the insertion hole of the pin 52 is 0.8 mm, the blade edge angle is 110 °, the number of grooves G is 360, and A maximum depth of 3 μm was used.

  In addition, the trench line TL was formed by fixing 100 loads applied to the scribe tool 150 and forming 100 lines for each formation condition of the assist line AL.

  Further, as a comparative example, the occurrence of extension of the vertical crack VC was evaluated under the same conditions as in the example except that a scribing wheel having grooves provided symmetrically with respect to the outer periphery was used.

  FIG. 11 is a plot of the rate of occurrence of vertical crack VC extension from all 100 trench lines TL in the example and comparative example (hereinafter referred to as VC establishment rate) against the load applied when forming the assist line AL. It is a graph.

  As shown in FIG. 11, in the comparative example, when the load is 1.5 N or less, a VC establishment rate of 90% or more is obtained, but the maximum value is only 93% when the load is 0.8 N. It was. On the other hand, in the example, a VC formation rate of 95% or more higher than that of the comparative example is obtained in a load range of 1.5 N or less where a VC establishment rate of 90% or more was obtained in the comparative example, and the load was 1 In the case of .1N, a VC establishment rate of 100% was achieved.

  These results indicate that the method according to the above-described embodiment having the groove portion having an asymmetric shape with respect to the outer periphery is suitable in terms of ensuring the extension of the vertical crack.

  In addition, if the scribing operation is performed using the scribing wheel 51 under the same conditions and the vertical crack is extended along 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 example also shows that the assist line AL can be formed by applying a load smaller than the load applied by the scribing wheel 51 during the scribing operation accompanied by the extension of the vertical crack. Furthermore, since the trench line TL can be formed by applying a load that is equal to or smaller than that of the assist line AL, the method according to the above-described embodiment is directly applied to the vertical crack by the scribe operation. It can be said that it is a technique that enables the extension of vertical cracks by applying a low load compared to the technique of extending the crack.

<Modifications and reference examples>
In the above-described embodiment, the assist line AL is formed after the trench line TL is formed. However, the formation order of the trench line TL and the assist line AL may be reversed.

  In the above-described embodiment, the trench line TL and the assist line AL are orthogonal to each other on the upper surface SF1 of the brittle material substrate W, but this is not an essential aspect, and the trench line associated with the formation of the assist line AL. As long as the extension of the vertical crack from the TL is suitably realized, the trench line TL and the assist line AL may be obliquely intersected.

  In the above-described embodiment, the trench line TL is formed by the scribe tool 150 in a state where the axial direction AX2 of the shank 152 is inclined toward the front of the moving direction DA, that is, the top surface SD1 is moved in the moving direction DA. This is done by sliding the diamond point 151 in a posture facing backward, but instead, in a state where the axial direction AX2 of the shank 152 is inclined toward the rear of the moving direction DA, that is, Alternatively, the trench line TL may be formed by sliding the diamond point 151 in a posture in which the top surface SD1 faces the front in the moving direction DA.

  Alternatively, in the above-described embodiment, the diamond point 151 is used to form the trench line TL. However, instead of this, the trench line TL may be formed by pressing and rolling the scribing wheel. Good. In this case, as the scribing wheel, it is preferable to use a scribing wheel that is not provided with a groove on the cutting edge.

  However, in the case of the latter two aspects, unlike the above-described embodiment, the planned extension direction of the vertical crack is on the downstream side of the trench line TL. Therefore, in these embodiments, the scribing wheel 51 is disposed so that the relatively deep portion G1 of the groove G faces the downstream side of the trench line TL, and the assist line AL is formed in the vicinity of the upstream side of the trench line TL. Like that.

  Also in this case, as in the above-described embodiment, the assist line AL is formed in a manner in which the assist crack AC is unevenly distributed on the downstream side of the trench line TL that is the expected extension direction of the vertical crack VC. In the planned extension direction, vertical crack extension from the trench line TL preferably occurs. As a result, the vertical crack can be extended with high certainty at the dividing position where the trench line TL is formed.

  Moreover, the formation mode of the groove | channel G in the scribing wheel 51 is not limited to what was shown in the above-mentioned embodiment. If an internal crack region in which a large number of assist cracks are unevenly distributed on one side of the assist line can be generated, for example, an asymmetric shape with respect to the outer periphery OP as disclosed in Patent Document 2 is provided. Various forming modes may be employed.

  Further, FIG. 12 is a partially enlarged sectional view passing through the groove G of the scribing wheel 51 according to the modification. In the above-described embodiment, the scribing wheel 51 (more specifically, the protrusion P) has an approximately isosceles triangle shape in cross-section including a ridge line and a pair of inclined surfaces sandwiching the ridge line. As a scribing wheel 51 in which an internal crack region in which a large number of assist cracks are unevenly distributed on one of the sides is formed, two inclined surfaces with different angles (θ1, θ2) with respect to the outer periphery OP as shown in FIG. The scribing wheel 51 which has can also 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 shank A1 (assist line TL) start point A2 (assist line TL) end point AL assist line AX axis center C (trench) Intersection of line TL and assist line AL CR Internal crack region DP Scribe direction G Groove (of scribing wheel 51) OP (outside of scribing wheel 51) P (protrusion of scribing wheel 51) PF (tip of scribing wheel 51) SF1 ( One main surface (upper surface) of brittle material substrate W
SF2 (of brittle material substrate W) other main surface (lower surface)
T1 Start point (of the trench line TL) T2 End point (of the trench line TL) TL Trench line VC Vertical crack W Brittle material substrate

Claims (6)

A method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction,
A trench line forming step of forming a trench line which is a line-shaped groove on one main surface of the brittle material substrate;
An assist line forming step of forming an assist line which is a processing mark intersecting the trench line by pressing and rolling a scribing wheel having a blade edge provided with a plurality of grooves at equal intervals on the outer peripheral portion on the one main surface; ,
With
In the trench line forming step, the trench line is formed so that a crackless state is maintained immediately below the trench line,
In the assist line forming step, the assist line is formed using the scribing wheel in which the plurality of grooves are formed in an asymmetric shape with respect to the outer periphery,
Extending a vertical crack from the trench line in the thickness direction of the brittle material substrate, starting from the intersection of the trench line and the assist line,
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming vertical cracks in a brittle material substrate according to claim 1,
In the assist line forming step, along with the formation of the assist line, an internal crack region in which a large number of assist cracks exist in the side of the assist line inside the brittle material substrate is generated,
The formation position of the trench line and the assist line is determined so that the internal crack region is formed on the planned extension direction side of the vertical crack on the trench line.
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming vertical cracks in a brittle material substrate according to claim 2,
Forming the assist line so as to intersect the trench line in the vicinity of the opposite side of the planned extension direction of the vertical crack on the trench line;
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming a vertical crack in a brittle material substrate according to any one of claims 1 to 3,
Forming the assist line after forming the trench line;
A method of forming vertical cracks in a brittle material substrate, characterized in that A method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction,
A trench line forming step of forming a trench line which is a line-shaped groove on one main surface of the brittle material substrate;
An assist line forming step of forming an assist line which is a processing mark intersecting the trench line by pressing and rolling a scribing wheel having a blade edge provided with a plurality of grooves at equal intervals on the outer peripheral portion on the one main surface; ,
With
In the trench line forming step, the trench line is formed so that a crackless state is maintained immediately below the trench line,
In the assist line forming step, the assist line is formed using the scribing wheel formed so that the plurality of grooves have different depths on the left and right sides of the outer periphery,
Extending a vertical crack from the trench line in the thickness direction of the brittle material substrate, starting from the intersection of the trench line and the assist line,
A method of forming vertical cracks in a brittle material substrate, characterized in that A method of dividing a 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 for forming a vertical crack according to any one of claims 1 to 5,
A breaking step of breaking the brittle material substrate along the vertical crack;
A method for dividing a brittle material substrate, comprising:

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