JP6955754B2 - Diamond cutting edge and substrate cutting method - Google Patents

Description

The present invention relates to a diamond cutting edge and a substrate cutting method.

In the manufacture of electrical equipment such as flat display panels or solar cell panels, it is often necessary to fragment the brittle substrate. In a typical dividing method, first, a crack line is formed on the brittle substrate. As used herein, the term "crack line" means a crack that has partially progressed in the thickness direction of the brittle substrate and extends in a line shape on the surface of the brittle substrate. Next, a so-called break step is performed. Specifically, by applying stress to the brittle substrate, cracks in the crack line are completely advanced in the thickness direction. This breaks the brittle substrate along the crack line.

According to Patent Document 1, a dent on the upper surface of the glass plate is formed at the time of scribe. In Patent Document 1, this depression is referred to as a "scribe line". Further, at the same time as the engraving of this scribe line, a crack extending directly downward from the scribe line occurs. As seen in the technique of Patent Document 1, in the conventional typical technique, a crack line is formed at the same time as the formation of the scribe line.

According to Patent Document 2, a dividing technique remarkably different from the above-mentioned typical dividing technique has been proposed. According to this technique, first, a groove shape called "scribe line" in Patent Document 2 is formed by causing plastic deformation by sliding the cutting edge on a brittle substrate. Hereinafter, in the present specification, this groove shape will be referred to as a "trench line". At the time when the trench line is formed, no crack is formed below it. After that, the crack line is formed by extending the crack along the trench line. That is, unlike the typical technique, a trench line without cracks is formed once, and then a crack line is formed along the trench line. After that, a normal break process is performed along the crack line.

In a typical conventional technique, the absence of cracks during scribing meant a failure of scribing. However, in the dividing technique of Patent Document 2, scribing intentionally forms a trench line without cracks. After that, a crack line along the trench line is generated. The trench line without cracks used in the technique of Patent Document 2 can be formed by sliding the cutting edge at a lower load than a typical scribe line with simultaneous formation of cracks. Since the load is small, the damage applied to the cutting edge is small. Therefore, according to this dividing technique, the life of the cutting edge can be extended.

Japanese Unexamined Patent Publication No. 9-188534 International Publication No. 2015/151755

After the formation of the trench line, in order to form the crack line along the trench line, it is necessary to give the brittle substrate a trigger to release the internal stress generated in the brittle substrate by the formation of the trench line. As one of the methods for giving this opportunity, the present inventor has been studying a method in which a cutting edge slid to form a trench line intersects with a first crack line formed in advance. .. In the case of this method, the second crack line extends from the intersection along the trench line, triggered by the cutting edge intersecting the first crack line at the intersection. According to this method, first and second crack lines intersecting each other are obtained.

According to the study of the present inventor, when the above method is applied, the following problems may occur. First, the brittle substrate divided along the first crack line and the second crack line is chipped at a portion corresponding to the intersection (hereinafter, also referred to as "intersection chipping"), and the intersection is chipped. In some cases, the size of the was larger than the permissible limit. When brittle substrates are fragmented along lines that intersect each other, small chips at the intersections are usually tolerated as unavoidable, but excessively large chips must be avoided. Secondly, when it is assumed that the second crack line extends from the intersection, the probability of occurrence of a phenomenon in which this extension does not occur (hereinafter, also referred to as "intersection jump") is so high that it cannot be ignored. It happened to be.

The present invention has been made to solve the above problems, and an object of the present invention is a diamond cutting edge and a substrate cutting method capable of stably suppressing the size of missing intersections and the frequency of occurrence of skipping intersections. Is to provide.

Diamond blade of the present invention, a 160 ° or 17 1 ° following top ridge between angles, and top angle 41.4 ° or 79.1 ° or less, and following the ridge line angle of 148 ° 130 ° or more, the Have.

According to the present invention, the size of missing intersections and the frequency of skipping intersections can be stably suppressed.

It is a flow figure which shows typically the substrate division method in Embodiment 1 of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a schematic partial cross-sectional view along the line III-III of FIG. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a schematic partial cross-sectional view along the line VV of FIG. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows roughly one step of the substrate cutting method in one Embodiment of this invention. It is a top view which shows the example of the phenomenon of the intersection skipping. It is a partial plan view which shows the example of the phenomenon of the intersection chipping observed on the brittle substrate before fragmentation. It is a partial plan view which shows an example of the phenomenon of the intersection chipping observed on the edge of a brittle substrate after fragmentation. It is a side view which shows typically the structure of the cutting tool which has a diamond cutting edge in one Embodiment of this invention. FIG. 8 is a plan view schematically showing the diamond cutting edge of FIG. 18 in the field of view of arrow XIX. It is a top view explaining the definition of the top surface angle which the diamond cutting edge of FIG. 19 has. It is a schematic partial cross-sectional view along the line XXI-XXI of FIG. 20, and is the figure explaining the definition of the ridge line angle which a diamond cutting edge has. It is a schematic partial cross-sectional view along the line XXII-XXII of FIG. 20, and is the figure explaining the definition of the angle between the top surface ridges which a diamond cutting edge has. It is a figure which shows the top surface angle determined by the ridge line angle and the angle between top surface ridge lines together with the example of the set angle between the top surface and the surface of a brittle substrate. It is a figure which shows the experimental result of the relationship between the condition of the ridge line angle and the angle between top surface ridge lines, and the evaluation result of the intersection jump / lack of intersection. It is a schematic diagram which shows the relationship between the condition of the ridge line angle and the angle between top surface ridge lines, which is inferred from the experimental result of FIG. 24, and the result of substrate division.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Board division method)
FIG. 1 is a flow chart schematically showing a substrate dividing method according to the present embodiment. 2, FIG. 4, and FIGS. 6 to 14 are plan views schematically showing a substrate dividing method. In these plan views, the trench line is shown by a broken line and the crack line is shown by a solid line for easy viewing, but the actual trench line is not broken and extends continuously. 3 and 5, respectively, are schematic partial cross-sectional views taken along line III-III (FIG. 2) and line VV (FIG. 4).

In step S10 (FIG. 1), at least one diamond cutting edge is prepared. The configuration of the diamond cutting edge will be described later.

With reference to FIG. 2, a glass substrate 11 (brittle substrate) is prepared as step S20 (FIG. 1). The glass substrate 11 has a surface SF1.

A trench line TL1 (first trench line) is formed by sliding any one of the above-mentioned at least one diamond cutting edges on the surface SF1 of the glass substrate 11. In the illustrated example, the trench line TL1 is formed from one position on the surface SF1 away from the edge of the surface SF1 to a position N1 on the edge of the surface SF1.

With reference to FIG. 3, the trench line TL1 is provided in the direction DC (FIG. 3) in which the glass substrate 11 intersects the extending direction (vertical direction in FIG. 2) of the trench line TL1 below the trench line TL1 in the thickness direction DT. It is formed so that a crackless state, which is a continuously connected state, can be obtained. In the crackless state, the trench line TL1 due to plastic deformation is formed, but no crack is formed along the trench line TL1. In order to obtain a crackless state, the load applied to the diamond cutting edge is so small that cracks do not occur when the trench line TL1 is formed, and plastic deformation that creates an internal stress state for generating crack lines in a later process is generated. It is adjusted to be large enough to be formed.

Further, referring to FIG. 4, as step S30 (FIG. 1), a crack line CL1 (first crack line) along the trench line TL1 (FIG. 2) is formed. In the present embodiment, the crack line CL1 begins to be formed triggered by the impact when the cutting edge cuts down the edge of the glass substrate 11 at the position N1. Specifically, this impact releases the internal stress generated by the formation of the trench line TL1, so that the crack line CL1 is formed.

With reference to FIG. 5, the crackless state (FIG. 3) described above is broken by the formation of the crack line CL1. In other words, the crack line CL1 below the trench line TL1 breaks the continuous connection of the glass substrate 11 in the direction DC intersecting the extending direction (vertical direction in FIG. 2) of the trench line TL1. Here, the "continuous connection" is, in other words, a connection that is not blocked by a crack. In the state where the continuous connection is broken as described above, the portions of the glass substrates 11 may be in contact with each other through the cracks in the crack line CL1. Further, a slightly continuous connection may be left immediately below the trench line TL1.

By repeating the same method with reference to FIG. 6, crack lines CL1a to CL1d are formed as a plurality of crack lines CL1.

With reference to FIG. 7, as step S40 (FIG. 1), step S10 (FIG. 1) is performed on the surface SF1 of the glass substrate 11 along the trajectory having the intersection (position N2a in the drawing) intersecting the crack line CL1a. ), One of the at least one diamond cutting edge is slid (see the arrow in the figure). As the cutting edge used in step S40, the cutting edge used in step S20 may be used again. Alternatively, a plurality of cutting edges are prepared in step S10 (FIG. 1), and other cutting edges not used in step S20 may be used in step S40. By the above sliding, a trench line TL2a (second trench line) is formed from the position N2p away from the edge of the surface SF1 to the position N2a. The trench line TL2a is formed so as to obtain a crackless state as in the case of the trench line TL1 (see FIG. 3).

Further, referring to FIG. 8, as step S50 (FIG. 1), a crack line CL2a (second crack line) is formed along the trench line TL2a from the intersection, that is, the position N2a to the position N2p (2nd crack line). See the dashed arrow in the figure). The trigger for this formation is the impact when the cutting edge intersects the crack line CL1a at the position N2a. This impact releases the internal stress generated by the formation of the trench line TL2a from the position N2p to the position N2a, so that the crack line CL2a extends from the position N2a to the position N2p. The crack line CL2a breaks the continuous connection of the glass substrate 11 below the trench line TL2a in the direction intersecting the extending direction (horizontal direction in FIG. 7) of the trench line TL2a (vertical direction in FIG. 8). .. That is, the crackless state is broken. The relationship between the trench line TL2a and the crack line CL2a is the same as the relationship between the trench line TL1 and the crack line CL1 shown in FIG.

With reference to FIG. 9, in step S40 (FIG. 1), the cutting edge slid to position N2a is further slid along a trajectory having an intersection (position N2b in the figure) intersecting the crack line CL1b. It can be moved (see the arrow in the figure). As a result, the trench line TL2a is further formed from the position N2a to the position N2b.

Further, referring to FIG. 10, in step S50 (FIG. 1), the crack line CL2a is further formed along the trench line TL2a from the intersection, that is, the position N2b to the position N2a (see the broken line arrow in the figure). .. The trigger for this formation is the impact when the cutting edge intersects the crack line CL1b at the position N2b. This impact releases the internal stress generated by the formation of the trench line TL2a from the position N2a to the position N2b, so that the crack line CL2a extends from the position N2b to the position N2a.

With reference to FIG. 11, as step S40 (FIG. 1), the cutting edge slid to position N2b (see FIG. 9) further has an intersection (position N2c in the figure) that intersects the crack line CL1c. It is slid along the track (see the arrow in the figure). As a result, the trench line TL2a is further formed from the position N2b to the position N2c.

Further, referring to FIG. 12, in step S50 (FIG. 1), the crack line CL2a is further formed along the trench line TL2a from the intersection, that is, the position N2c to the position N2b (see the broken line arrow in the figure). .. The trigger for this formation is the impact when the cutting edge intersects the crack line CL1c at the position N2c. This impact releases the internal stress generated by the formation of the trench line TL2a from the position N2b to the position N2c, so that the crack line CL2a extends from the position N2c to the position N2b.

With reference to FIG. 13, in step S40 (FIG. 1), the cutting edge (see FIG. 12) slid to the position N2c further moves to the intersection (position N2d in the drawing) that intersects the crack line CL1d. It can be slid. As a result, the trench line TL2 is further formed from the position N2c to the position N2d. Then, in step S50 (FIG. 1), the crack line CL2a is further formed from the position N2d to the position N2c along the trench line TL2a by the impact that the cutting edge intersects the crack line CL1d at the position N2d.

The cutting edge that intersects the crack line CL1d at the position N2d is further slid to the position N2q and then separated from the glass substrate 11. The position N2q may be separated from the edge of the surface SF1 of the glass substrate 11.

The trench line TL2a and the crack line CL2a along the trench line TL2a are formed by the steps of FIGS. 7 to 13. By repeating the same steps, as shown in FIG. 14, trench lines TL2b to TL2d and crack lines CL2b to CL2d along the respective trench lines CL2b to CL2d are formed. The trench lines TL2a to TL2d are also collectively referred to as the trench line TL2 (second trench line). Further, the crack lines CL2a to CL2d are also collectively referred to as a crack line CL2 (second crack line).

In step S60 (FIG. 1), the glass substrate 11 is divided along the crack line CL1 and the crack line CL2. That is, a so-called break process is performed. The break step can be performed by applying an external force to the glass substrate 11. Thereby, the glass substrate 11 can be divided along the lines intersecting each other.

If the crack line completely progresses in the thickness direction DT (see FIG. 5) at the time of its formation, the formation of the crack line and the division of the glass substrate 11 occur at the same time.

(About the phenomenon of skipping intersections and missing intersections)
FIG. 15 shows an example of the surface SF1 of the glass substrate 11 when the phenomenon of intersection skipping occurs in the process of forming the crack line CL2. Unlike the case of FIG. 14, the crack line CL2 is not formed in a part of the portion where the crack line CL2 was supposed to be formed, and only the trench line TL2 is formed. The probability of intersection skipping depends on the shape of the diamond cutting edge, as will be described later.

FIG. 16 is a partial plan view showing an example of the phenomenon of intersection chipping observed on the glass substrate 11 after the formation of the crack line CL1 and the crack line CL2 and before the division of the glass substrate 11. In the figure, the broken line arrow indicates the forming direction of the crack line CL2, and the solid line arrow indicates the forming direction of the trench line TL2 (not shown) formed prior to the crack line CL2. The position N2 represents the intersection of the crack line CL1 and the crack line CL2. Ideally, the only cracks that occur near the intersection (position N2) are the crack line CL1 and the crack line CL2. However, in reality, when the crack line CL2 starts to be formed at the position N2, a crack CA extending from a position deviated from the position N2 may be formed. The crack CA extends from a position on the crack line CL1 and joins the crack line CL2.

Further, referring to FIG. 17, when the glass substrate 11 on which the crack CA (FIG. 16) is formed is divided, a portion corresponding to the position N2 is chipped (hereinafter, also referred to as “intersection chipped CP”). .. It is unavoidable that a small missing intersection CP occurs, but an excessively large missing intersection CP must be avoided. The size of the intersection missing CP depends on the shape of the diamond cutting edge, as will be described later.

(Cutting tool with diamond cutting edge)
FIG. 18 is a side view schematically showing a cutting tool 50 having a diamond cutting edge 51 as a cutting edge prepared in step S10 (FIG. 1). In the figure, the state in which the diamond cutting edge 51 slides in the direction DA on the surface SF1 of the glass substrate 11 is shown by a broken line. Further, FIG. 19 is a plan view schematically showing the diamond cutting edge 51 (FIG. 18) in the field of view of arrow XIX. The cutting tool 50 has a diamond cutting edge 51 and a shank 52. The diamond cutting edge 51 is held by the shank 52 as its holder. The shank 52 extends along the axial direction AX. The diamond cutting edge 51 is preferably attached to the shank 52 so that the normal direction of the top surface SD1 is approximately along the axial direction AX.

The diamond cutting edge 51 is provided with a top surface SD1 and a plurality of surfaces surrounding the top surface SD1. These plurality of surfaces include the side surface SD2 and the side surface SD3. The top surface SD1, the side surface SD2, and the side surface SD3 face different directions and are adjacent to each other. The diamond cutting edge 51 has a vertex PP formed by merging the top surface SD1, the side surface SD2, and the side surface SD3 with each other. Further, the diamond cutting edge 51 has a ridge line PS formed by combining the side surface SD2 and the side surface SD3 with each other. The ridge line PS extends linearly from the apex PP.

Preferably, the diamond cutting edge 51 is made of single crystal diamond. More preferably, crystallographically speaking, the top surface SD1 is a {001} plane. A diamond that is not a single crystal may be used, and for example, a polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may be used. Alternatively, polycrystalline diamond sintered from fine graphite or non-graphite carbon without containing a binder such as an iron group element, or sintered diamond obtained by bonding diamond particles with a binder such as an iron group element. May be used.

The sliding of the diamond cutting edge 51 on the surface SF1 of the glass substrate 11 is such that the apex PP is brought into contact with the surface SF1 and the set angle GS between the top surface SD1 and the surface SF1 is set to 0 ° or more in advance. This is done by moving the diamond cutting edge 51 in the direction DA while keeping the angle at an angle. The direction DA is from the ridgeline PS toward the top surface SD1. Preferably, the direction DA is along a straight line obtained by projecting the ridge PS onto the surface SF1. Further, preferably, the angles formed by each of the side surface SD2 and the side surface SD3 and the surface SF1 are equal to each other.

(Angle that characterizes the diamond cutting edge)
FIG. 20 is a plan view of the same field of view as FIG. The top surface SD1 has an angle tangent to the apex PP. The angle of this angle is the top angle GC. FIG. 21 is a schematic partial cross-sectional view taken along the line XXI-XXI of FIG. 20, whose field of view is perpendicular to the ridgeline PS. In this cross section, the diamond cutting edge 51 has an angle formed by the side surfaces SD2 and SD3 around the ridgeline PS. The angle of this angle is the ridgeline angle GA. FIG. 22 is a schematic partial cross-sectional view taken along the line XXII-XXII of FIG. 20, whose field of view is parallel to the ridgeline PS and perpendicular to the top surface SD1. In this cross section, the diamond cutting edge 51 has an angle formed by the top surface SD1 and the ridge line PS around the apex PP. The angle of this angle is the angle between the top ridges GB.

FIG. 23 shows the top surface angle GC (FIG. 20) geometrically determined depending on the conditions of the ridge line angle GA (FIG. 21) and the top surface ridge line angle GB (FIG. 22) in the first line. In addition, when a preferable example of the set angle GS (FIG. 18) under the conditions is examined, the values are shown in parentheses in the second row. It should be noted that the condition indicated by "(F)" is substantially impossible to carry out the substrate dividing method in the present embodiment because the preferable range of the load condition applied to the diamond cutting edge 51 is extremely narrow. It is a thing. Further, under the condition that the ridge line angle GA is 130 ° and the top surface ridge line angle GB is 171 °, the substrate division method can be implemented by the set angle GS = 3 °, but at the time of forming the trench line TL1. Since the difference between the suitable load and the suitable load at the time of forming the trench line TL2 is large, it is difficult to set the load condition. Further, under the condition that the ridge line angle GA was 150 ° and the top surface ridge line angle GB was 170 °, the required load was larger than other conditions.

FIG. 24 is a diagram showing an experimental result of the relationship between the conditions of the ridge line angle GA and the top surface ridge line angle GB and the evaluation result of the intersection jump / lack of intersection. The evaluation results of the intersection skipping and the intersection missing are shown before and after the "/", respectively.

In relation to the evaluation of the intersection jump, when the intersection jump can be eliminated, the width of the range between the load at the time of forming the trench line TL1 and the load at the time of forming the trench line TL2 at that time was also evaluated. The evaluation result "A" indicates that the intersection jump could be eliminated even when the load at the time of forming the trench line TL2 was reduced to about the load at the time of forming the trench line TL1. In the evaluation result "B", the intersection jump occurred when the load at the time of forming the trench line TL2 was reduced to about the load at the time of forming the trench line TL1, but the load at the time of forming the trench line TL2 was at the time of forming the trench line TL1. It is shown that the intersection jump could be eliminated when the load was made larger than the load. The evaluation result "C" indicates that even if the load was adjusted, the result without the intersection jump was obtained only unstablely.

Regarding the evaluation of the lack of intersections, the evaluation result "A" indicates that the size of the chip was smaller than the evaluation results "B" and "C", and the evaluation result "B" indicates that the size of the chip was the evaluation result "A". It indicates that it was between "C" and "C", and the evaluation result "C" indicates that the size of the chip was larger than the evaluation result "B".

The condition indicated by "F" in FIG. 24 corresponds to the condition indicated by "(F)" in the table of FIG. 23, and the implementation of the substrate dividing method in the present embodiment is substantially implemented. It was impossible.

In the figure, the patterns attached to each condition represent a comprehensive evaluation. The hatching of the checkered pattern shows that both the evaluation of the intersection skipping and the intersection chipping were good, and the load condition on the diamond cutting edge 51 was easily adjusted. The hatching of the diagonal pattern indicates that although the appropriate range of the load condition on the diamond cutting edge 51 is slightly narrow, good results are obtained almost stably with respect to the evaluation of both the intersection skipping and the intersection chipping. The boxed broken line indicates that good results for both skipping and missing intersections were obtained only in an unstable manner due to the difficulty in adjusting the load conditions on the diamond cutting edge 51. Enclosing the solid line indicates that it was practically impossible to implement the substrate dividing method in the present embodiment.

In view of the above experimental results, the angle between the top ridges GB (FIG. 22) is set to 160 ° or more and 172 ° or less. Preferably, the angle GB between the top ridges is 165 ° or more. Further, preferably, the angle GB between the top ridges is 171 ° or less. The top angle GC (FIG. 21) is preferably 37.1 ° or more and 79.1 ° or less. Preferably, the top angle GC is 46.5 ° or more. Further, preferably, the top surface angle GC is 64.0 ° or less. A diamond cutting edge 51 satisfying these angular conditions is used in each of steps S20 and S40 (FIG. 1).

FIG. 25 is a schematic view showing the relationship between the conditions of the ridge line angle GA and the top surface ridge line angle GB and the result of substrate division, which are inferred from the experimental results of FIG. 24. In the two-dimensional space formed by the ridge angle GA and the top ridge angle GB, the triangular region RA having the point CS, the point CT, and the point CU satisfies the condition that the substrate dividing method in the present embodiment can be easily performed. Shown.

In the region RQ where the ridge angle GA (FIG. 21) is excessive, which is defined by the straight line LQ including the point CS and the point CT, it is difficult to adjust the appropriate load on the diamond cutting edge 51. It shows the conditions that are considered difficult to implement. The region RR where the angle between the top ridges GB (FIG. 22) is excessive, which is defined by the straight line LR including the point CT and the point CU, indicates a condition in which it is considered substantially impossible to carry out the substrate dividing method. ing. It is considered that this is related to the fact that when the angle GB between the top ridges is close to 180 °, the adjustment range of the set angle GS (FIG. 18) is extremely limited, so that it is easy to adjust the load. .. The region RP with an excessive top angle GC (FIG. 20) defined by the straight line LP including the point CU and the point CS indicates a condition in which the lack of intersection is likely to be excessive. It is estimated that the point CS corresponds to the ridgeline angle GA = about 130 ° and the top surface ridgeline angle GB = about 160 °. It is estimated that the point CT corresponds to the ridgeline angle GA = about 135 ° and the top surface ridgeline angle GB = about 173 °. It is estimated that the point CU corresponds to the ridgeline angle GA = about 148 ° and the top surface ridgeline angle GB = about 169 °.

(Summary of effect)
When the angle GB between the top ridges is 160 ° or more and 172 ° or less, the size of the intersection chipping and the frequency of occurrence of intersection skipping can be stably suppressed. Preferably, the angle GB between the top ridges is 165 ° or more. As a result, the size of the missing intersection and the frequency of skipping the intersection can be suppressed more reliably. Preferably, the angle GB between the top ridges is 171 ° or less. As a result, the size of the missing intersection and the frequency of skipping the intersection can be suppressed more reliably.

Preferably, the top angle GC is 37.1 ° or more. Thereby, the load condition of the diamond cutting edge 51 can be easily set. Therefore, the substrate can be divided more stably. Preferably, the top angle GC is 79.1 ° or less. As a result, the size of the missing intersection can be suppressed more reliably. Preferably, the top angle GC is 46.5 ° or more. Thereby, the load condition of the diamond cutting edge 51 can be set more easily. Preferably, the top angle GC is 79.1 ° or less. Thereby, the load condition of the diamond cutting edge 51 can be set more easily. Preferably, the top angle GC is 64.0 ° or less. As a result, the size of the missing intersection can be suppressed more reliably.

GA Ridge angle GB Top ridge angle GC Top angle CL1, CL1a to CL1d, CL2, CL2a to CL2d Crack line SD1 Top surface SD2, SD3 Side surface SF1 Surface GS setting angle PP Vertex TL1, TL2, TL2a to TL2d Trench line PS Ridge 11 Glass substrate (brittle substrate)
51 Diamond cutting edge

Claims (5)

Comprising a 160 ° or 17 1 ° following top ridge between angles, and top angle 41.4 ° or 79.1 ° or less, and following the ridge line angle of 148 ° 130 ° or more, a diamond cutting edge. The diamond cutting edge according to claim 1, wherein the angle between the top ridges is 165 ° or more. The diamond cutting edge according to claim 1 or 2 , wherein the top surface angle is 46.5 ° or more. The diamond cutting edge according to any one of claims 1 to 3 , wherein the top surface angle is 64.0 ° or less. A step of preparing the diamond cutting edge according to any one of claims 1 to 4 as at least one cutting edge, and
A step of forming a first trench line by sliding any one of the at least one cutting edge on a brittle substrate.
A step of forming a first crack line along the first trench line after forming the first trench line, and a step of forming the first crack line.
A step of forming a second trench line by sliding any one of the at least one cutting edge on the brittle substrate along an orbit having an intersection intersecting with the first crack line.
A step of forming a second crack line from the intersection along the second trench line, and
A method of dividing a substrate.

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