TWI769268B - Diamond Knife Blade and Substrate Breaking Method - Google Patents

Abstract

Provides a diamond blade that can stably suppress the size of intersection defects and the frequency of intersection jumps. The diamond blade edge 51 has an angle between the top surface ridges of 160° or more and 172° or less. The angle between the ridgelines of the top surface is the angle of the angle formed by the top surface SD1 and the ridgeline PS around the vertex PP.

Description

Diamond Knife Blade and Substrate Breaking Method

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

In the manufacture of electrical equipment such as flat panel display panels or solar cell panels, it is often necessary to break brittle substrates. In a typical breaking method, crack lines are first formed in the brittle substrate. The term "crack line" in this specification refers to a crack that partially progresses in the thickness direction of the brittle substrate and extends linearly on the surface of the brittle substrate. Next, a so-called breaking step is performed. Specifically, by applying stress to the brittle substrate, the crack of the crack line is completely advanced in the thickness direction. Thereby, the brittle substrate is divided along the crack line.

According to Patent Document 1, the depressions on the upper surface of the glass plate are generated during scribing. In this patent document 1, this recess is called "scribing line". In addition, a crack extending from the scribe line in the directly downward direction is generated at the same time as the scribe line is scribed. As shown in the technique of this patent document 1, in a conventional typical technique, a crack line is formed at the same time as a scribe line is formed.

According to Patent Document 2, a breaking technique which is significantly different from the above-described typical breaking technique is proposed. According to this technique, first, plastic deformation occurs with the sliding of the blade on the brittle substrate, thereby forming a groove shape called "scribe line" in Patent Document 2. In this specification, the shape of this groove is hereinafter referred to as a "groove line". At the point when the trench lines were formed, no cracks were formed under them. The cracks are then extended along the trench lines, thereby forming crack lines. That is, unlike the typical technique, trench lines without cracks are formed first, and then crack lines are formed along the trench lines. Then, along the crack line Carry out the usual breaking procedure.

In typical known techniques, failure to form cracks during scribing represents a scribing failure. However, in the breaking technique of the above-mentioned Patent Document 2, trench lines without cracks are intentionally formed by scribing. After this, crack lines along the groove lines are generated. Compared with a typical scribe line formed at the same time as a crack, the groove line without crack used in the technique of the above-mentioned Patent Document 2 can be formed by the sliding of the blade under a lower load. With a smaller load, the damage applied to the blade can be reduced. Therefore, according to the breaking technology, the life of the blade can be extended.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-188534

[Patent Document 2] International Publication No. 2015/151755

After the trench lines are formed, in order to form crack lines along them, the brittle substrate must be given an opportunity to release the internal stress generated in the brittle substrate by the formation of the trench lines. As one of the methods for giving this opportunity, the present inventors studied a method in which a blade edge that slides to form a groove line intersects a preliminarily formed first crack line. In the case of this method, the second crack line extends from the intersection along the groove line by the intersection of the blade edge and the first crack line at the intersection. According to this method, the first and second crack lines intersecting with each other are obtained.

According to the research of the present inventors, when the above-mentioned method is applied, the following disadvantages may occur. First, a defect (hereinafter also referred to as "intersection defect") occurs in the portion corresponding to the above-mentioned intersection of the brittle substrate divided along the first crack line and the second crack line, and the size of the intersection defect may exceed increase within the allowable limit. In the case of breaking a brittle substrate along intersecting lines When a small defect occurs at the intersection, it is usually allowed as a last resort, but excessively large defects must be avoided. Second, it is considered that the second crack line extends from the above-mentioned intersection, but the occurrence probability of the phenomenon that the extension does not occur (hereinafter also referred to as "intersection jumping") may be so high that it cannot be ignored.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a diamond blade and a substrate cutting method capable of stably suppressing the size of intersection defects and the frequency of occurrence of intersection jumps.

The diamond blade of the present invention has a top surface ridgeline angle of 160° or more and 171° or less, a top surface angle of 41.4° or more and 79.1° or less, and a ridgeline angle of 130° or more and 148° or less.

According to the present invention, it is possible to stably suppress the size of intersection defects and the frequency of occurrence of intersection jumps.

11: Glass substrate (brittle substrate)

50: Cutting Tools

51: Diamond Knife Blade

52: handle

AX: axis direction

DA: direction

DT: thickness direction

GA: Ridge angle

GB: Angle between top ridge lines

GC: Top face angle

CL1, CL1a~CL1d, CL2, CL2a~CL2d: Crack lines

SD1: Top surface

SD2, SD3: side

SF1: Surface

GS: set angle

PP: vertex

TL1, TL2, TL2a~TL2d: trench line

PS: Ridgeline

XIX: Arrow

Fig. 1 is a flow chart schematically showing a substrate cutting method according to an embodiment of the present invention.

Fig. 2 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

[FIG. 3] It is a schematic partial cross-sectional view taken along the line III-III of FIG. 2. [FIG.

[ Fig. 4] Fig. 4 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

[FIG. 5] It is a schematic partial cross-sectional view taken along the line V-V of FIG. 4. [FIG.

Fig. 6 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention picture.

[ Fig. 7] Fig. 7 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

[ Fig. 8] Fig. 8 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

[ Fig. 9] Fig. 9 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 10 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 11 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 12 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 13 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 14 is a plan view schematically showing a step of a substrate cutting method according to an embodiment of the present invention.

Fig. 15 is a plan view showing an example of the phenomenon that the intersection point jumps out.

16 is a partial plan view showing an example of the phenomenon of intersection defects observed on a brittle substrate before breaking.

Fig. 17 is a partial plan view showing an example of the phenomenon of intersection defects observed at the edge of the brittle substrate after breaking.

Fig. 18 is a side view schematically showing the configuration of a cutting tool having a diamond blade blade according to an embodiment of the present invention.

Fig. 19 is a plan view schematically showing the diamond blade of Fig. 18 in the field of view of arrow XIX.

FIG. 20 is a plan view illustrating the definition of the top surface angle of the diamond blade of FIG. 19 .

Fig. 21 is a schematic partial cross-sectional view taken along the line XXI-XXI in Fig. 20, and is a diagram for explaining the definition of the ridge angle of the edge of the diamond blade.

Fig. 22 is a schematic partial cross-sectional view taken along the line XXII-XXII in Fig. 20, and is a diagram for explaining the definition of the angle between the top face ridges of the diamond blade.

FIG. 23 is a schematic diagram showing the relationship between the conditions of the ridgeline angle and the angle between the ridgelines on the top surface estimated from the experimental results in Table 2, and the results of the cutting of the substrate.

Hereinafter, embodiments of the present invention will be described based on the drawings.

(Substrate breaking method)

FIG. 1 is a flow chart schematically showing a substrate cutting method according to the present embodiment. FIG. 2 , FIG. 4 , and FIGS. 6 to 14 are plan views schematically showing a method of dividing a substrate. In these top views, the groove lines are represented by dashed lines and the crack lines are represented by solid lines for the convenience of identification, but the actual groove lines are not dashed lines, but extend continuously. 3 and 5 are schematic partial cross-sectional views taken along lines III-III (FIG. 2) and V-V (FIG. 4), respectively.

In step S10 (FIG. 1), at least one diamond blade is prepared. The composition of the diamond blade is explained below.

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

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

Referring to FIG. 3 , the trench line TL1 is formed in a manner to obtain a crack-free state, the crack-free state is below the trench line TL1 in the thickness direction DT, and the glass substrate 11 is in the extending direction of the trench line TL1 ( FIG. 2 ). The state of continuous connection in the direction DC (FIG. 3) intersecting. In the crack-free state, although the groove line TL1 caused by plastic deformation is formed, the crack along it is not formed. In order to obtain a crack-free state, the adjustment is carried out in the following manner: the load applied to the edge of the diamond knife is small to the extent that no cracks are generated when the groove line TL1 is formed, and is large enough to cause the internal stress state for the purpose of generating crack lines in the subsequent steps. the degree of plastic deformation.

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 starts to be formed by the impact when the blade cuts off the edge of the glass substrate 11 at the position N1. Specifically, by this impact, the internal stress generated with the formation of the trench line TL1 is released, thereby forming the crack line CL1.

Referring to FIG. 5, by forming the crack line CL1, the above-mentioned crack-free state (FIG. 3) is broken. In other words, below the trench line TL1 , the glass substrate 11 is disconnected continuously in the direction DC intersecting with the extending direction of the trench line TL1 (the longitudinal direction in FIG. 2 ) by the crack line CL1 . The so-called "continuous connection" here, in other words, is a connection that is not covered by cracks. In addition, in the state where the continuous connection is disconnected as described above, parts of the glass substrate 11 can also be in contact with each other through the crack of the crack line CL1. In addition, a little continuous connection may remain at the nearest position below the trench line TL1.

6 , by repeating the same method, crack lines CL1a to CL1d are formed as a plurality of crack lines CL1.

Referring to FIG. 7 , as step S40 ( FIG. 1 ), on the surface SF1 of the glass substrate 11 along the track having the intersection with the crack line CL1a (in the figure, the position N2a ), in step S10 ( FIG. 1 ) One of the prepared at least one diamond blade blade slides (in the figure, refer to the arrow). As the blade used in step S40, the blade used in step S20 can be reused. Alternatively, a plurality of blade edges are prepared in step S10 ( FIG. 1 ), and other blade edges that are not used in step S20 may be used in step S40 . By the above-mentioned sliding, the trench line TL2a (second trench line) is formed from the position N2p separated from the edge of the surface SF1 to the position N2a. The trench line TL2a is formed so as to be free from cracks as in the case of the trench line TL1 (see FIG. 3).

8, as step S50 (FIG. 1), along the trench line TL2a, a crack line CL2a (second crack line) is formed from the position N2a, which is the intersection, to the position N2p (see the dotted arrow in the figure). The opportunity for this formation is the impact when the blade crosses the crack line CL1a at the position N2a. By this impact, the internal stress generated by the formation of the trench line TL2a from the position N2p to the position N2a is released, whereby the crack line CL2a extends from the position N2a to the position N2p. By the crack line CL2a, below the trench line TL2a, the glass substrate 11 is broken and continuous in the direction (the vertical direction in FIG. 8) intersecting with the extending direction (the horizontal direction in FIG. 7) of the trench line TL2a. the connection. That is, the crack-free state is interrupted. 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. 5 .

9, as step S40 (FIG. 1), the blade edge slid to position N2a is further slid (refer to arrow in the figure) along a track having an intersection with crack line CL1b (in the figure, position N2b). Thereby, the trench line TL2a is further formed from the position N2a to the position N2b.

10 , as step S50 ( FIG. 1 ), crack line CL2a is formed along trench line TL2a from position N2b, which is the intersection, to position N2a (see dotted arrow in the figure). The opportunity for this formation is the impact when the blade crosses the crack line CL1b at the position N2b. By this impact, the internal stress generated by the formation of the trench line TL2a from the position N2a to the position N2b is released, whereby the crack line CL2a extends from the position N2b to the position N2a.

Referring to FIG. 11, as step S40 (FIG. 1), the blade edge (refer to FIG. 9) slid to the position N2b is further along the track having the intersection with the crack line CL1c (in the figure, the position N2c) It slides along the road (in the figure, refer to the arrow). Thereby, the trench line TL2a is further formed from the position N2b to the position N2c.

12 , as step S50 ( FIG. 1 ), the crack line CL2a is further formed along the trench line TL2a from the position N2c, which is the intersection, to the position N2b (in the figure, refer to the dotted arrow). The opportunity for this formation is the impact when the blade crosses the crack line CL1c at the position N2c. By this impact, the internal stress generated by the formation of the trench line TL2a from the position N2b to the position N2c is released, whereby the crack line CL2a extends from the position N2c to the position N2b.

13 , as step S40 ( FIG. 1 ), the blade edge (see FIG. 12 ) slid to position N2c is further slid to the intersection (position N2d in the figure) intersecting with crack line CL1d. Thereby, the trench line TL2 is further formed from the position N2c to the position N2d. Then, as step S50 ( FIG. 1 ), the crack line CL2a is further formed from the position N2d to the position N2c along the groove line TL2a by the impact of the knife edge crossing the crack line CL1d at the position N2d.

The blade that intersects with the crack line CL1d at the position N2d slides further to the position N2q, and then separates from the glass substrate 11 . The position N2q may be separated from the edge of the surface SF1 of the glass substrate 11 .

Through the steps of FIGS. 7 to 13 described above, the trench line TL2a and the crack line CL2a along the trench line TL2a are formed. 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 are formed. The trench lines TL2a to TL2d are collectively referred to as trench lines TL2 (second trench lines). In addition, the crack lines CL2a to CL2d are collectively referred to as crack lines CL2 (second crack lines).

As 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 breaking step is performed. The breaking 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 crossing each other.

In addition, in the case where the crack line completely progresses in the thickness direction DT (refer to FIG. 5 ) at the time of its formation, the formation of the crack line occurs simultaneously with the division of the glass substrate 11 .

(About the phenomenon of intersection jumping and intersection defect)

FIG. 15 shows an example of the surface SF1 of the glass substrate 11 in the case where the phenomenon of the intersection point jumping occurs in the step 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 is considered to be formed, but only the trench line TL2 is formed. The probability of an intersection jumping out depends on the shape of the diamond blade as described later.

16 is a partial plan view showing an example of the phenomenon of intersection defects 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 arrows indicate the formation direction of the crack line CL2, and the solid-line arrows indicate the formation direction of the trench line TL2 (not shown) formed before it. In addition, the position N2 represents the intersection of the crack line CL1 and the crack line CL2. Ideally, the cracks generated in the vicinity of the intersection (position N2) are only the crack line CL1 and the crack line CL2. Actually, however, 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 merges with the crack line CL2.

17 , when the glass substrate 11 on which the crack CA ( FIG. 16 ) is formed is divided, a defect (hereinafter, also referred to as “intersection defect CP”) occurs in the portion corresponding to the above-mentioned position N2 . The generation of small intersection point defects CP is tolerated as a last resort, but excessively large intersection point defects CP must be avoided. The size of the intersection defect CP depends on the shape of the edge of the diamond knife as described later.

(Cut with a diamond blade)

FIG. 18 is a side view schematically showing the cutting tool 50 having the diamond blade edge 51 as the blade edge prepared in step S10 (FIG. 1). In the figure, the situation where the diamond blade edge 51 slides in the direction DA on the surface SF1 of the glass substrate 11 is represented by a dotted line. 19 is a plan view schematically showing the diamond blade edge 51 (FIG. 18) in the field of view of the arrow XIX. The cutting tool 50 has a diamond blade edge 51 and a handle 52 . The diamond blade edge 51 is held on the handle 52 as its holder. The handle 52 extends along the axial direction AX. diamond The blade edge 51 is preferably mounted on the handle 52 in such a manner that the normal direction of the top surface SD1 is approximately along the axial direction AX.

A top surface SD1 and a plurality of surfaces surrounding the top surface SD1 are provided on the diamond blade edge 51 . The plurality of surfaces include side surfaces SD2 and side surfaces SD3. The top surface SD1, the side surface SD2, and the side surface SD3 are oriented in different directions from each other, and are adjacent to each other. The diamond blade edge 51 has a vertex PP formed by a top surface SD1, a side surface SD2, and a side surface SD3 merging with each other. In addition, the diamond blade edge 51 has a ridgeline PS formed by merging the side surfaces SD2 and SD3 with each other. The ridgeline PS extends linearly from the vertex PP.

Preferably, the diamond blade blade 51 is made of single crystal diamond. In particular, crystallographically, the top surface SD1 is preferably a {001} plane. In addition, diamonds that are not single crystals can also be used, for example, polycrystalline diamonds synthesized by a CVD (Chemical Vapor Deposition, chemical vapor deposition) method can be used. Alternatively, polycrystalline diamonds sintered with particulate graphite or non-graphitic carbon without binding materials such as iron group elements, or sintered diamonds in which diamond particles are bound with a binding material such as iron group elements can also be used. .

The sliding of the diamond blade edge 51 on the surface SF1 of the glass substrate 11 is performed in the following manner: the vertex PP is brought into contact with the surface SF1, and the set angle GS between the top surface SD1 and the surface SF1 is kept at 0° or more in advance. Set the angle, and move the diamond blade edge 51 in the direction DA. 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 ridgeline PS onto the surface SF1. In addition, it is preferable that the angle formed by each of the side surface SD2 and the side surface SD3 and the surface SF1 is equal to each other.

(Characteristic angle of the diamond blade)

FIG. 20 is a plan view of the same view as FIG. 19 . The top surface SD1 has a corner that meets the vertex PP. The angle of this angle is the top surface angle GC. FIG. 21 is a schematic partial cross-sectional view taken along the line XXI-XXI of FIG. 20, the field of view being perpendicular to the ridge line PS. In this cross section, the diamond blade 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. Figure 22 is along the line XXII-XXII of Figure 20 A schematic partial cross-sectional view, the field of view is parallel to the ridgeline PS and perpendicular to the top surface SD1. In this cross section, the diamond blade edge 51 has an angle formed by the top surface SD1 and the ridge PS around the vertex PP. The angle of this angle is the angle GB between the ridgelines of the top surface.

Table 1 is a table as follows: The top surface angle GC (FIG. 20), which is geometrically determined depending on the conditions of the ridgeline angle GA (FIG. 21) and the top surface ridgeline angle GB (FIG. 22), is shown in Section 1. 1 line, and when a preferred example of the setting angle GS (FIG. 18) under this condition is studied, its value is shown in brackets on the 2nd line. In addition, since the preferable range of the load conditions applied to the diamond blade edge 51 is extremely narrow, the conditions indicated as "(F)" are virtually impossible to implement the substrate cutting method of the present embodiment. In addition, under the condition that the ridgeline angle GA is 130° and the angle GB between the top face ridgelines is 171°, although the substrate cutting method can be implemented by setting the angle GS=3°, the preferred load for forming the groove line TL1 is , The difference between the optimum load and the optimum load when forming the trench line TL2 is large, so it is difficult to set the load condition. Other In addition, under the condition that the ridgeline angle GA is 150 degrees and the top surface ridgeline angle GB is 170°, the necessary load is larger than other conditions.

Table 2 is a table showing the experimental results of the relationship between the conditions of the ridgeline angle GA and the angle between the top ridgelines GB, and the evaluation results of intersection jumping/intersection defect. Before and after "/", the evaluation results of intersection jumping and intersection defect are shown respectively.

In connection with the evaluation of the jumping out of the intersection point, when the situation of the jumping out of the intersection point can be eliminated, the breadth of the range of the load when the trench line TL1 is formed and the load when the trench line TL2 is formed at that time is also evaluated. The evaluation result "A" indicates that when the load at the time of formation of the trench line TL2 is reduced to the level of the load at the time of formation of the trench line TL1, the jumping of the intersection can be eliminated. The evaluation result "B" indicates that if the load when the trench line TL2 is formed is reduced to the level of the load when the trench line TL1 is formed, although the intersection point jumps out, if the load when the trench line TL2 is formed is greater than that of the trench The load when the line TL1 is formed can be eliminated. Except for the jump out of the intersection. The evaluation result "C" means that even if the load is adjusted, the result that there is no intersection jumping can only be obtained stably.

Regarding the evaluation of intersection defects, the evaluation result "A" indicates that the size of the defect is smaller than the evaluation results "B" and "C", and the evaluation result "B" indicates that the size of the defect is between the evaluation results "A" and "C". "C" indicates that the size of the defect is larger than the evaluation result "B".

In addition, the condition indicated by "F" in Table 2 corresponds to the condition indicated by "(F)" in Table 1, and it is virtually impossible to implement the substrate cutting method of the present embodiment.

In the figure, the pattern indicated for each condition represents a comprehensive evaluation. The grid bottom system of the plaid pattern indicates that the evaluations of the intersection point jump and the intersection point defect are good, and the load conditions for the diamond blade 51 are easy to adjust. The net bottom system of the inclined pattern indicates that the appropriate range of the load condition of the diamond blade 51 is slightly narrow, but the evaluation of both the jumping out of the intersection and the defect of the intersection, basically, good results are obtained stably. The encircling system of the dotted line indicates that, since it is difficult to adjust the load conditions for the diamond blade 51, only good results can be obtained in the evaluation of both the intersection jumping and the intersection defect stably. The system enclosed by the solid line indicates that it is virtually impossible to implement the substrate cutting method of the present embodiment.

In view of the above-mentioned experimental results, the angle GB ( FIG. 22 ) between the ridgelines of the top surface is set to be 160° or more and 172° or less. Preferably, the angle GB between the ridgelines on the top surface is 165° or more. In addition, it is preferable that the angle GB between the ridgelines of the top surface is 171° or less. The top surface angle GC ( FIG. 21 ) is preferably set to 37.1° or more and 79.1° or less. Preferably, the top surface angle GC is 46.5° or more. Moreover, it is preferable that the top surface angle GC is 64.0 degrees or less. The diamond blade edge 51 that satisfies the angle conditions is used in steps S20 and S40 ( FIG. 1 ), respectively.

23 is a schematic diagram showing the relationship between the conditions of the ridgeline angle GA and the angle GB between the top ridgelines estimated from the experimental results in Table 2, and the results of substrate breaking. In the two-dimensional space formed by the ridgeline angle GA and the angle GB between the top ridgelines, the area RA of the triangle having the point CS, the point CT, and the point CU represents the condition that the substrate cutting method of the present embodiment can be easily performed.

The ridgeline angle GA (FIG. 21) defined by the straight line LQ including the point CS and the point CT passes through The large area RQ represents the conditions under which it is considered difficult to implement the substrate cutting method of the present embodiment because it is difficult to adjust an appropriate load on the diamond blade edge 51 . The region RR where the angle GB between the top surface ridgelines ( FIG. 22 ) defined by the straight line LR including the point CT and the point CU is too large represents a condition that is considered to be virtually impossible to implement the substrate cutting method. This is considered to be related to the fact that when the angle GB between the top surface ridges is close to 180°, the adjustment range of the set angle GS ( FIG. 18 ) is extremely limited, so that the adjustment of the load is likely to be difficult. The region RP in which the top surface angle GC ( FIG. 20 ) defined by the straight line LP including the point CU and the point CS is too large represents a condition where it is considered that the intersection defect is likely to become too large. The point CS is estimated to correspond to the ridgeline angle GA=about 130° and the top surface ridgeline angle GB=about 160°. The point CT is estimated to correspond to the ridgeline angle GA=about 135° and the top surface ridgeline angle GB=about 173°. The point CU is estimated to correspond to the ridgeline angle GA=about 148° and the top surface ridgeline angle GB=about 169°.

(Summary of the effect)

By setting the angle GB between the ridgelines on the top surface to be 160° or more and 172° or less, the size of the intersection defect and the frequency of occurrence of the intersection point can be stably suppressed. Preferably, the angle GB between the ridgelines on the top surface is 165° or more. Thereby, the size of the intersection defect and the frequency of occurrence of the intersection drop can be suppressed more reliably. Preferably, the angle GB between the ridgelines on the top surface is 171° or less. Thereby, the size of the intersection defect and the frequency of occurrence of the intersection drop can be suppressed more reliably.

Preferably, the top surface angle GC is 37.1° or more. Thereby, the load condition of the diamond blade edge 51 can be easily set. Therefore, the substrate cutting can be performed more stably. Preferably, the top surface angle GC is 79.1° or less. Thereby, the size of the intersection defect can be suppressed more surely. Preferably, the top surface angle GC is 46.5° or more. Thereby, the load condition of the diamond blade edge 51 can be set more easily. Preferably, the top surface angle GC is 79.1° or less. Thereby, the load condition of the diamond blade edge 51 can be set more easily. Preferably, the top surface angle GC is 64.0° or less. Thereby, the size of the intersection defect can be suppressed more reliably.

11‧‧‧Glass substrate (brittle substrate)

50‧‧‧Cutting tools

51‧‧‧Diamond Blade

52‧‧‧Handle

AX‧‧‧axis direction

DA‧‧‧direction

DT‧‧‧Thickness direction

GS‧‧‧Setting angle

PP‧‧‧Top

PS‧‧‧edge

SD1‧‧‧Top

SD3‧‧‧Side

SF1‧‧‧Surface

XIX‧‧‧arrow

Claims (6)

A diamond blade blade, which has a top surface ridgeline angle of more than 160° and less than 171°, a top surface angle of more than 41.4° and less than 79.1°, and a ridgeline angle of more than 130° and less than 148°. According to the diamond blade of claim 1, the angle between the above-mentioned ridgelines on the top surface is more than 165°. The diamond blade of claim 1 or 2, wherein the above-mentioned top surface angle is more than 46.5°. The diamond blade of claim 1 or 2, wherein the above-mentioned top surface angle is below 64.0. According to the diamond blade of claim 3, the angle of the top surface is below 64.0°. A substrate cutting method, comprising: the step of preparing the diamond blade edge of any one of claims 1 to 5 as at least one blade edge; by sliding any one of the at least one blade edge on a brittle substrate The step of forming a first trench line; after forming the first trench line, the step of forming a first crack line along the first trench line; the track, the step of sliding any one of the at least one blade edge on the brittle substrate to form a second groove line; and forming a second crack line along the second groove line from the intersection point steps.

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