JP6519381B2 - Method of forming vertical cracks in brittle material substrate and method of dividing brittle material substrate - Google Patents

Description

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

  The manufacturing process of a flat display panel or a solar cell panel generally includes the 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 division, a method of forming a scribe line on a substrate surface using a scribe tool such as a diamond point or a cutter wheel and extending a crack (vertical crack) in the thickness direction of the substrate from the scribe line is widely used. There is. When a scribe line is formed, the vertical crack may completely extend in the thickness direction and the substrate may be divided, but the vertical crack may only partially extend in the thickness direction. In the latter case, after the formation of the scribe line, stress is applied which is called a breaking step. The substrate is divided along the scribe line by completely advancing the vertical crack in the thickness direction by the break process.

  As a method for extending a vertical crack by forming such a scribe line, a method for forming a linear processing mark serving as a starting point (trigger) for extending a vertical crack, which is also referred to as an assist line, has already been known. (See, for example, Patent Document 1).

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

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

  For example, in the method using an assist line as disclosed in Patent Document 1, a scribing tool such as a cutter wheel or a diamond point is used as a substrate in forming a scribing line for division as compared with a method not using this. There is an advantage that the applied force (impact) can be reduced. For example, even in a mode of forming a scribe line by applying a weak force (load) that makes it difficult to extend a vertical crack, it is possible to preferably extend the vertical crack from the scribe line using the assist line as a trigger. is there.

  However, a high yield (certain division) is required particularly in the division of a brittle material substrate made in the manufacturing process of a mass-produced product, the technique disclosed in Patent Document 1 necessarily requires vertical cracks starting from the assist line. The extension does not guarantee its 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 reliability at a predetermined dividing position of a brittle material substrate.

  In order to solve the above-mentioned problems, 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, wherein one surface of the brittle material substrate is line-shaped A trench line forming step of forming a trench line which is a groove, and crossing the trench line by pressing and rolling a scribing wheel provided with a cutting edge provided with a plurality of grooves at equal intervals on the one main surface An assist line forming step of forming an assist line which is a processing mark, and in the trench line forming step, the trench line is formed immediately below the trench line so as to maintain a crackless state; In the line forming step, the plurality of grooves are formed in an asymmetrical 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 point of the trench line and the assist line. .

  The invention according to claim 2 is the method for forming a vertical crack in the brittle material substrate according to claim 1, wherein, in the assist line forming step, the inside of the brittle material substrate is formed along with the formation of the assist line. The trench line is formed such that an internal crack area having a large number of assist cracks is generated on the side of the assist line, and the internal crack area is formed on the planned extension direction side of the vertical crack on the trench line. And determining the formation position of the assist line.

  The invention according to claim 3 is the method for forming a vertical crack in the brittle material substrate according to claim 2, wherein the assist line is formed on the trench line in the vicinity of the opposite side of the planned extension direction of the vertical crack on the trench line. It is characterized in that it is formed to intersect.

  The invention according to claim 4 is the method for forming a vertical crack in a brittle material substrate according to any one of claims 1 to 3, characterized in that the assist line is formed after the trench line is formed. I assume.

  The invention according to claim 5 is a method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction, and forming a trench line which is a line-shaped groove on one main surface of the brittle material substrate And an assist line, which is a processing mark that intersects the trench line, by pressing and rolling 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 forming step, forming the trench line so as to maintain a crackless state immediately below the trench line in the trench line forming step; and in the assist line forming step, A plurality of grooves formed to have different depths on the left and right 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 for dividing a brittle material substrate in a thickness direction, wherein a vertical crack is formed in the brittle material substrate by the method for forming a vertical crack according to any one of claims 1 to 5. A vertical crack forming process, and a breaking process of breaking the brittle material substrate along the vertical crack are characterized.

  According to the present invention, vertical cracks can be extended with high certainty at a predetermined dividing position of a brittle material substrate, so that the brittle material substrate can be reliably divided at the dividing position. It is possible to

FIG. 2 schematically shows a configuration of scribing apparatus 100. FIG. FIG. 7 is an enlarged view of a scribing wheel 51 in part A. It is a top view of the brittle material substrate W which illustrates the mode after trench line TL formation. It is a figure showing roughly the composition of diamond point 150 used for formation of trench line TL. FIG. 35 is a zx partial cross sectional view including a vertical cross section of a trench line TL. It is a top view of the brittle material substrate W which illustrates the mode at the time of assist line AL formation. It is a top view of brittle material substrate W which illustrates a situation of extension of vertical crack VC accompanying formation of assist line AL. It is a top view of brittle material substrate W which illustrates a situation of extension of vertical crack VC accompanying formation of assist line AL. FIG. 17 is a zx partial cross sectional view including vertical cross sections of a trench line TL and a vertical crack VC. It is a schematic diagram which shows the mode of assist line AL vicinity at the time of the vertical crack VC being formed. It is the graph which plotted VC establishment rate to the load applied in formation of assistant 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.

<Scribing apparatus>
FIG. 1 is a view schematically showing the configuration of a scribing apparatus 100 used in the embodiment of the present invention. The scribing apparatus 100 is generally used when dividing a brittle material substrate W such as a glass substrate, a ceramic substrate, a semiconductor substrate or the like in the thickness direction DT at a predetermined dividing position and reducing the size thereof. In the embodiment, the scribing device 100 is used to form an assist line AL (see FIG. 6 or the like) which is performed to extend a vertical crack at a dividing position on the one principal surface SF1 side of the brittle material substrate W. In the present embodiment, assist line AL is formed perpendicular to trench line TL (see FIG. 3 etc.) formed at the dividing position on the main surface SF1 side, and is perpendicular to trench line TL. It is a processing mark which becomes a starting point (trigger) when extending a crack. The trench line TL is a fine line-shaped groove (concave portion) located immediately below the trench line TL where the vertical crack is formed. The 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 for 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), and by providing these mechanisms, the scribing head 2 holds the scribing tool 50 in the scribing apparatus 100. It can move relative to the table 1 in the horizontal plane. Hereinafter, in order to simplify the description, it is assumed that the scribing head 2 moves relative to the table 1 in the scribing direction DP shown in FIG. 1 during the scribing operation.

  The scribing tool 50 is a tool for performing scribing on 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 beaded bead shape), and includes a cutting edge along the outer periphery OP. FIG. 2 is an enlarged view of the scribing wheel 51 in the portion A shown in FIG. 2 (a) is an enlarged cross-sectional view of a portion A of a plane including the outer periphery OP, and FIG. 2 (b) is an outer periphery of the scribing wheel 51 shown by the arrow B for a part of the portion A. It is the figure seen from the perpendicular direction.

  The outer periphery OP of the scribing wheel 51 appears to be macroscopically in the form of a uniform circle as shown in FIG. 1, but in fact, as shown in FIG. Fine grooves G are provided at equal intervals, and between adjacent grooves G is a protrusion P, thereby forming a blade edge PF. That is, the scribing wheel 51 is a so-called grooved wheel having a cutting edge PF in which the grooves G and the projections P alternately exist. The protrusion P has a substantially isosceles triangle shape in cross section, 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 asymmetrical shape with respect to the outer periphery OP. This is realized by providing the groove G at an angle with respect to the plane including the outer periphery OP. Thereby, the groove G has a relatively deep portion G1 (left side of the outer periphery OP in FIG. 2B) on the left and right of the outer periphery OP and an outer periphery in a relatively shallow portion G2 (FIG. 2B) And the right side of the OP).

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

  As the scribing wheel 51 having such a groove shape, for example, it is possible to apply one used for forming a scribe line when cutting off a closed curve area.

  The pin 52 is vertically inserted at the position of the axial center AX of the scribing wheel 51. The holder 53 is held by the scribing 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 rotatably supports the pin 52 and the scribing wheel 51 around the axial center AX. More specifically, in the scribing wheel 51, the portion G1 of the groove G is positioned on the right side (the front side in the drawing) with respect to the scribing direction DP shown in FIG. It is pivotally supported so that it is located on the back side). Further, the holder 53 horizontally supports the pin 52 so that the surface formed by the cutting edge PF (outer periphery OP) of the scribing wheel 51 extends in the vertical direction.

  In 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, for example. . From the viewpoint of reducing the surface roughness of the ridge line and the inclined surface described above, the whole scribing wheel 51 may be made of single crystal diamond.

  In scribing apparatus 100 having the above configuration, one main surface (hereinafter also referred to as the upper surface) of brittle material substrate W horizontally mounted and fixed on table 1 with the other main surface SF2 as the mounting surface In a state where the scribing wheel 51 is in pressure contact with the SF 1, the scribing head 2 holding the scribing tool 50 is moved in the scribing direction DP. Then, the scribing wheel 51 in a state of being in pressure contact with the brittle material substrate W rolls around the axial center AX in the direction indicated by the arrow RT in a state where the cutting edge PF slightly intrudes into the brittle material substrate W. As a result, on the upper surface SF1 of the brittle material substrate W, plastic deformation occurs along the moving direction of the scribing wheel 51 along with the press-contacting rolling of the scribing wheel 51. In the present embodiment, the press-contacting and rolling operation of the scribing wheel 51 causing such plastic deformation is referred to as a scribing operation by the scribing wheel 51.

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

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

<Procedure for forming a vertical crack>
Next, the procedure of forming the vertical crack at the dividing position using the assist line AL performed in the present embodiment will be described. FIGS. 3 to 9 are views showing the state of formation of such vertical cracks in stages. In the following, the case where a plurality of dividing positions (division lines) parallel to a pair of opposite sides with respect to the rectangular brittle material substrate W are set in advance will be described as an example. In each figure, the xy-z coordinates of a right-handed system in which the formation advancing direction of the assist line AL is the x-axis positive direction, the formation advancing direction of the trench line TL is the y-axis positive direction, and the vertically upward 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 a state after formation of the trench line TL. FIG. 4 schematically shows a configuration of scribe tool 150 used to form 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 division position when the brittle material substrate W is viewed in plan from the upper surface SF1 side.

  In the present embodiment, a scribe tool 150 provided with a diamond point 151 is used to form the trench line TL. The diamond point 151 has, for example, a truncated pyramid shape 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, the plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). Top surface SD1, side surfaces SD2 and SD3 face in mutually different directions, and are adjacent to each other. At the diamond point 151, a blade edge PF2 is formed by a ridge line PS composed of the side surfaces SD2 and SD3 and a vertex PP formed by three surfaces of the top surface SD1 and the side surfaces SD2 and SD3. As shown in FIG. 4A, the diamond point 151 is held in a mode in which the top surface SD1 is the lowermost end on one end side of a rod-like (columnar) shank 152.

  When the scribing tool 150 is used, as shown in FIG. 4A, the axial direction AX2 of the shank 152 is inclined from the vertical direction toward the moving direction DA forward (y-axis positive direction) by a predetermined angle In the state, that is, the diamond point 151 is brought into contact with the upper surface SF1 of the brittle material substrate W with the top surface SD1 directed rearward (in the y-axis negative direction) in the movement direction DA. Then, the blade tip PF2 of the diamond point 151 is made to slide by moving the scribing tool 150 forward in the moving direction DA while keeping such a contact state. As a result, plastic deformation occurs along the moving direction DA of the diamond point 151. In the present embodiment, the sliding operation of the diamond point 151 which causes such plastic deformation is also referred to as a scribing 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 that occurs on the upper surface SF1 of the brittle material substrate W by sliding the diamond point 151 in a state where the posture of the scribing tool 150 is symmetrical with respect to the moving direction DA. . In such a case, as schematically shown in FIG. 5, the trench line TL is formed as a groove having a generally symmetrical cross-sectional shape perpendicular to the extending direction.

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

  In FIG. 3, although the start point T1 and the end point T2 of the trench line TL are slightly separated from the end of the brittle material substrate W, this is not an essential aspect, and the brittleness to be divided is Depending on the type of the material substrate W, the use of the individual pieces after division, etc., either one or both may be set as the end position of the brittle material substrate W. However, in the aspect in which the start point T1 is the end of the brittle material substrate W, the cutting edge PF2 of the scribing tool 150 is different from the case where the position slightly separated from the end is the start point T1 as illustrated in FIG. Since the impact to be applied is large, it is necessary to be careful in terms of the life of the cutting edge PF2 and the occurrence of an unexpected vertical crack.

  In addition, the formation of the trench line TL at each of the plurality of dividing positions may be in a mode of sequentially forming using the scribing tool 150 in a processing device (not shown) including one scribing tool 150, or a plurality of trenches It may be an aspect of forming in parallel by using a processing device for forming the line TL.

  In forming the trench line TL, formation of the trench line TL is reliably performed, which corresponds to a load applied by the scribing tool 150 (corresponding to a force for pushing the scribing tool 150 against the upper surface SF1 of the brittle material substrate W from above vertically). However, in the thickness direction DT of the brittle material substrate W, it is set such that extension of the vertical crack from the trench line TL does not occur (FIG. 5).

  In other words, the formation of the trench line TL is performed so as to maintain the state (crackless state) in which the brittle material substrate W is continuously connected in the direction crossing the trench line TL immediately below the trench line TL. Incidentally, when the trench line TL is formed by the corresponding method, internal stress remains as a result of plastic deformation in the vicinity of the trench line TL of the brittle material substrate W (within about 5 μm to about 10 μm from the trench line TL). Do.

  The formation of the trench line TL is performed, for example, by setting the load applied by the scribing tool 150 to a smaller value than when forming the scribing line with the extension of the vertical crack using the same scribing tool 150. Is realized.

  In the crackless state, even if the trench line TL is formed, there is no extension of the vertical crack from the trench line TL, so even if a bending moment acts on the brittle material substrate W, the vertical crack is formed. Breakdown along the trench line TL is less likely to occur than in the case where it is formed.

  Following the formation of the trench line TL, the assist line AL is formed by the scribing apparatus 100 provided with the scribing tool 50. FIG. 6 is a top view of the brittle material substrate W illustrating how the assist line AL is formed. 7 and 8 are top views of the brittle material substrate W illustrating how the vertical cracks VC extend with the formation of the assist lines AL. FIG. 9 is a zx partial cross-sectional view including the vertical cross-sections of the trench line TL and the vertical crack VC.

  In the present embodiment, as shown in FIG. 6, in the vicinity of the downstream side of trench line TL, assist line AL is in the positive direction of the x-axis indicated by arrow AR2 (as orthogonal to trench line TL) as starting point A1. From the upper surface SF1 of the brittle material substrate W to the plastic deformation in the range of the end point A2 to the end point A2.

  The formation of the assist line AL is performed in a mode in which the formation advancing direction of the assist line AL indicated by the arrow AR2 matches the scribing direction DP (x-axis positive direction). That is, in a state where the scribing wheel 51 is in pressure contact with the upper surface SF1 of the brittle material substrate W, the scribing wheel 51 is rolled by moving the scribing head 2 in the scribing direction DP. Then, each time the assist line AL intersects with 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. If this is the case, extension of the vertical cracks VC from the trench line TL to the thickness direction DT of the brittle material substrate W occurs sequentially as shown in FIG. 9 toward the upstream side of the trench line TL.

  As in the case of forming the trench line TL, the formation of the assist line AL is not intended to extend the vertical crack immediately under it, and therefore the scribing wheel 51 is used to form the assist line AL. The load to be applied can also be set to a smaller value as compared to the case of forming a scribe line accompanied with the extension of the vertical crack using the same scribing wheel 51.

  Finally, as shown in FIG. 8, extension of the vertical cracks VC from the trench line TL occurs at all the dividing positions. That is, the formation of the assist line AL is triggered (the assist line AL is a trigger), and at each division position of the brittle material substrate W which has been in the crackless state although the trench line TL is formed until then. , And a vertical crack VC extending from the trench line TL.

  This is because, when the trench line TL is formed using the scribe tool 150 including the diamond point 151, 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 one direction. In the present embodiment in which the trench line TL is formed in a mode in which the top surface SD1 of the diamond point is arranged on the upstream side above the trench line TL, in the present embodiment, after the assist line AL is formed, the vertical side is vertical on the upstream side of the trench line TL. The crack VC extends but is difficult to extend in the opposite direction.

  The brittle material substrate W in which the vertical cracks VC are formed at the dividing position in such a mode is given to a predetermined breaking device (not shown). In the breaking apparatus, a breaking step of extending the vertical cracks 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, the formation of the trench line TL at the dividing position does not involve the extension of the vertical crack VC, so that scribing for the dividing position is performed simultaneously with the formation of the scribing line as in the prior art. There is an advantage that the load applied to the scribing tool 50 can be reduced as compared to the case where it is performed. Such an advantage contributes to prolonging the life of the scribing tool 50 used for dividing at the dividing position.

<Details of vertical crack extension>
FIG. 10 is a schematic view 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. Although FIGS. 6 to 8 illustrate the assist line AL as a substantially continuous linear processing mark, microscopically, as shown in FIG. As a result of reflecting the shape of the blade edge PF in which the protrusions P and the protrusions P are alternately present, a short line segment of about a few tens of μm is formed as a processing mark in an intermittent manner.

  When the assist line AL is formed in the positive direction of the x-axis (direction perpendicular to the y-axis) which is the scribing direction DP, it is the inside of the brittle material substrate W over the entire forming position and the negative side in the y-axis direction (FIG. 10). In (b), an internal crack region CR in which innumerable assist cracks originating from the assist line AL exist is formed on the side of the assist line AL below the assist line AL).

  More specifically, the internal crack region CR is generated in a mode of being distributed within a range from the direction of (−y, −z) to the direction of −z, 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 maximum from the assist line AL in the y-axis negative direction more than 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 forming the assist line AL. That is, when the assist line AL is formed in the positive direction of the x-axis, which is the scribing direction DP, the scribing wheel 51 used to form the assist line AL moves the relatively deep portion G1 of the groove G into the planned extension direction of the vertical crack VC. Facing the upstream side (that is, the y-axis direction negative side) of the trench line TL, and the relatively shallow portion G2 faces the downstream side (the y-axis direction positive side) of the trench line TL which is the opposite direction. , Be rolled. In this case, as described above, the portion G1 is located on the right side with respect to the scribe direction DP, that is, on the upstream side (the negative side in the y-axis direction) of the trench line TL which is the planned extension direction of the vertical crack VC. Large stress acts. Therefore, it is considered that the formation of the assist crack from the assist line AL is likely to occur on the y axis direction negative side.

  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 also in the vicinity of the location where the assist line AL intersects with the trench line TL. As described above, since the internal stress remains in the vicinity of the trench line TL, the assist line is formed such that the internal crack region CR is formed on the planned extension direction side of the vertical crack VC of the trench line TL. In this case, the formation of the internal crack region CR in the presence region of the residual internal stress triggers the release of the residual internal stress in the vicinity of the trench line TL. As a result, as shown by arrow AR4 in FIG. 10 (b), the vertical crack from the trench line TL is directed toward the planned extension direction of the vertical crack VC (the upstream side of the trench line TL in the present embodiment). Extension of VC occurs. This is the detail of the extension of the vertical crack VC by the method according to the above-described embodiment.

  Although not shown in FIG. 10, the stress acts also on the y-axis direction positive side where the relatively shallow portion G2 of the groove G is located, and the formation of the assist crack is stochastically As this is a phenomenon that occurs, assist cracking may occur. However, since the acting stress is smaller than that on the side where the portion G1 is located, the occurrence probability is small, and even if the portion G2 is scribed in the planned extension direction of the vertical crack VC, the present embodiment described above As compared with the method in the above, the certainty of extension of the vertical crack VC does not increase.

  Alternatively, an aspect in which the assist line AL is formed by using a scribing wheel provided with a groove having a symmetrical shape with respect to the outer periphery is also conceivable, in which case the formation of the internal crack region CR is made to the left and right of the scribing direction DP. However, in view of the intended extension of the vertical crack VC in the intended direction of extension of the vertical crack VC, the interior is more positively internal on the opposite side of the intended extension direction of the vertical crack VC. Since there is no particular merit in forming the crack region CR, again in this case, the certainty of the extension of the vertical crack VC does not increase as compared with the method in the above-described embodiment.

  As described above, according to the present embodiment, when dividing a brittle material substrate at a predetermined dividing position, a vertical crack does not occur immediately below the forming position according to the dividing position. The formation of the trench line and the scribing wheel intentionally inclined in the horizontal plane, 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 By performing the formation, the vertical crack can be extended with high certainty at the dividing position. By forming the vertical cracks reliably, it becomes possible to reliably divide the brittle material substrate at the dividing position in the subsequent breaking step. In such a case, the load applied by the scribing wheel in forming the trench line and the assist line can be set to a smaller value than in the case of performing the scribing operation accompanied with the extension of the vertical crack.

<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 under different conditions for forming the assist line AL, and the occurrence of the vertical crack VC was evaluated. . A 0.3 mm thick glass substrate was used as the brittle material substrate W.

  Specifically, the assist line AL changes the load applied to the scribing wheel 51 to seven levels of 0.8N, 1.1N, 1.5N, 1.9N, 2.3N, 2.6N and 3.0N. It formed. The moving speed of the scribing 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 angle is 110 °, the number of grooves G is 360, and the groove G is The maximum depth of 3 μm was used.

  In addition, the load applied to the scribing tool 150 was fixed, and 100 trench lines TL were formed for each formation condition of the assist line AL.

  Further, as a comparative example, the occurrence of the 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 plots the incidence of extension of vertical cracks VC from all 100 trench lines TL (hereinafter referred to as VC establishment ratio) in the example and the comparative example against the load applied in forming the assist line AL. 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 remains 93% of that in the case of 0.8 N load. It was On the other hand, in the example, in the load range of 1.5 N or less where the VC formation rate of 90% or more was obtained in the comparative example, a VC formation rate of 95% or more higher than that of the comparative example is obtained. In the case of 1N, a VC establishment rate of 100% was achieved.

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

  In addition, if a scribing operation is performed using the scribing wheel 51 under the same conditions to extend the vertical crack along with the formation of the scribing line, it is necessary to apply a load of at least about 3 to 4 N. The results of the example also show that the formation of the assist line AL can be performed by applying a load smaller than the load applied by the scribing wheel 51 in the scribing operation accompanied by the extension of the vertical crack. Furthermore, since formation of the trench line TL is possible by application of a load equal to or smaller than that at the time of formation of the assist line AL, the method according to the above-described embodiment directly generates vertical cracks by scribing operation. It can be said that this is a method that enables the extension of the vertical crack by the application of a low load as compared with the method of extending the.

<Modification and Reference Example>
In the above embodiment, the assist line AL is formed after the trench line TL is formed, but the formation order of the trench line TL and the assist line AL may be reversed.

  In the above 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 a trench line associated with the formation of the assist line AL. The trench line TL and the assist line AL may obliquely intersect as long as the extension of the vertical crack from the TL is preferably realized.

  In the above embodiment, the trench line TL is formed by the scribing tool 150 in a state where the axial direction AX2 of the shank 152 is inclined forward in the moving direction DA, that is, the moving direction DA of the top surface SD1. It is performed by sliding the diamond point 151 in a posture directed rearward, but instead, in a state in which the axial direction AX2 of the shank 152 is inclined rearward in 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 is directed forward in the moving direction DA.

  Alternatively, in the above embodiment, the diamond point 151 is used to form the trench line TL, but instead, 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 one having no 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 modes, scribing wheel 51 is arranged such that relatively deep portion G1 of trench G faces the downstream side of trench line TL, and assist line AL is formed in the vicinity of the upstream side of trench line TL. Let's do it.

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

  Moreover, the formation aspect 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 can be generated on one side of the assist line, for example, the shape is asymmetric with respect to the outer periphery OP as disclosed in Patent Document 2. Various formation modes having may be adopted.

  Furthermore, FIG. 12 is a partial enlarged cross-sectional view which passes through the groove G of the scribing wheel 51 according to a modification. In the above embodiment, although the scribing wheel 51 (more specifically, the protrusion P thereof) has a substantially isosceles triangle shape in cross section in which the ridge line and the pair of inclined surfaces sandwiching the ridge line form an assist line As a scribing wheel 51 in which an internal crack area in which a large number of assist cracks are unevenly distributed on one of the sides, two inclined planes having different angles (θ1 and θ2) with respect to the outer periphery OP as shown in FIG. The scribing wheel 51 can also be used.

1 table 2 scribing head 50, 150 scribing tool 51 scribing wheel 52 pin 53 holder 100 scribing device 151 diamond point 152 shank A1 starting point A2 (for assist line TL) end point A2 (for assist line TL) end point AL assist line AX axis center C (trench Line TL and assist line AL intersection point CR internal crack area DP scribing direction G (for scribing wheel 51) groove OP (for scribing wheel 51) perimeter P (for scribing wheel 51) protrusion PF (for scribing wheel 51) cutting edge SF1 (for scribing wheel 51) One main surface (upper surface) of the brittle material substrate W)
SF2 (of brittle material substrate W) other main surface (lower surface)
T1 (trench line TL) start point T2 (trench line TL) end point 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 a thickness direction,
A trench line forming step of forming a trench line which is a linear 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 cutting edge provided with a plurality of grooves at equal intervals on an outer peripheral portion on the one main surface; ,
Equipped with
In the trench line forming step, the trench line is formed to maintain a crackless state 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 asymmetrical shape with respect to the outer periphery,
A vertical crack is extended in the thickness direction of the brittle material substrate from the trench line starting from the intersection of the trench line and the assist line as a start point.
A method of forming a vertical crack in a brittle material substrate, characterized in that A method of forming a vertical crack in a brittle material substrate according to claim 1,
In the assist line forming step, an internal crack region in which a large number of assist cracks exist inside the brittle material substrate and to the side of the assist line is generated along with the formation of the assist line.
The formation positions of the trench line and the assist line are determined such 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 a vertical crack in a brittle material substrate, characterized in that A method for forming a vertical crack in a brittle material substrate according to claim 2, wherein
The assist line is formed to cross 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 a vertical crack 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, comprising:
Forming the assist line after forming the trench line;
A method of forming a vertical crack 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 a thickness direction,
A trench line forming step of forming a trench line which is a linear 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 cutting edge provided with a plurality of grooves at equal intervals on an outer peripheral portion on the one main surface; ,
Equipped with
In the trench line forming step, the trench line is formed to maintain a crackless state 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 to have different depths on the left and right of the outer periphery,
A vertical crack is extended in the thickness direction of the brittle material substrate from the trench line starting from the intersection of the trench line and the assist line as a start point.
A method of forming a vertical crack 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 of 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 of dividing a brittle material substrate, comprising:

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