TWI740945B - Breaking method of brittle substrate - Google Patents

Abstract

The present invention prepares a tool tip (51) with a front end (51N) of axial symmetry in the axial direction (AX). Make the axis direction (AX) of the tool tip (51) perpendicular to one surface (SF1) of the brittle substrate (4), and slide the front end (51N) of the tool tip (51) on one surface (SF1), thereby forming Groove line without cracks. The crack line is formed by extending the crack of the brittle substrate (4) in the thickness direction (DT) along the trench line (TL). Break the brittle substrate (4) along the crack line.

Description

Breaking method of brittle substrate

The present invention relates to a method for breaking a brittle 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, first, crack lines are formed on 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 in a line on the surface of the brittle substrate. Next, a so-called breaking step is carried out. Specifically, by applying stress to the brittle substrate, the cracks of the crack lines are fully developed in the thickness direction. Thereby, the brittle substrate is broken along the crack line.

According to Patent Document 1, a depression on the upper surface of the glass plate is generated during scribing. In this Patent Document 1, the depression is called "scribing." In addition, at the same time when the scribe line is engraved, a crack extending directly below from the scribe line is generated. As shown in the technique of Patent Document 1, in the conventional typical technique, the crack line is formed at the same time as the scribe line is formed.

According to Patent Document 2, a breaking technique that is significantly different from the above-mentioned typical breaking technique is proposed. According to this technique, first, the blade tip slides on the brittle substrate to generate plastic deformation, thereby forming a groove shape called "scribing" in Patent Document 2. In this specification, this groove shape is hereinafter referred to as "groove line". At the point when the trench line was formed, no crack was formed below it. That Then, the crack line is formed by extending the crack along the groove line. That is, unlike the typical technique, groove lines without cracks are temporarily formed, and then crack lines are formed along the groove lines. Thereafter, the usual breaking steps are carried out along the crack line.

The groove line without cracks used in the technique of Patent Document 2 mentioned above can be formed by sliding of the tool tip under a lower load than a typical scribing line with simultaneous formation of cracks. The small load reduces the damage to the tool tip. Therefore, according to this breaking technology, the life of the tool tip can be prolonged.

In the above-mentioned Patent Document 2, a cutting tool having a blade tip and a shank as its holder is used. The cutting tool has an axial direction, and the handle extends along the axial direction. The groove line is formed by sliding the tip of the knife on the brittle substrate. The tip of the knife is held by a holder extending in the axial direction. The axis direction is inclined with respect to the upper surface of the brittle substrate. The direction in which the axis direction is projected onto the brittle substrate corresponds to the sliding direction of the tool tip.

[Prior Technical Literature] [Patent Literature]

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

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

According to the aforementioned Patent Document 2, the direction in which the axial direction is projected onto the glass substrate corresponds to the sliding direction of the blade tip. In other words, there is anisotropy in the effect of the blade tip of the brittle substrate on the substrate. Therefore, the axis direction must be adjusted corresponding to the sliding direction of the tool tip. Therefore, it must be The breaking device of the brittle substrate is provided with a mechanism for adjusting the posture of the blade tip in a way that the axis direction corresponds to the sliding direction. Moreover, especially when the sliding direction of the blade tip is not fixed, a mechanism for controlling the posture of the blade tip must be provided. The necessity of adjusting and controlling the posture of the knife tip will bring about the disadvantages such as the increase of the cost of the breaking device, the increase of the time required for the steps, and the decrease of the accuracy of the scribing position.

The present invention was completed to solve the above problems, and its purpose is to provide a method for breaking a brittle substrate without adjusting the posture of the tool tip according to the sliding direction of the tool tip.

The method for breaking a brittle substrate according to one aspect of the present invention has the following steps a) to e).

a) Prepare a brittle substrate with one side and a thickness direction perpendicular to one side.

b) Prepare a cutting edge with a front end that has axial symmetry in the axial direction, and the radius of curvature of the front end is set to 3 μm or more and 40 μm or less, and the size of the front end in the axial direction is set to 0.5 μm or more.

c) By making the axis direction of the tool tip perpendicular to one surface of the brittle substrate, and sliding the front end of the tool tip on one surface, a groove line with a groove shape is formed by plastic deformation on one surface of the brittle substrate. The groove line is formed in a state in which the brittle substrate is continuously connected in a direction crossing the groove line under the groove line, that is, a crack-free state.

d) The crack line is formed by extending the crack of the brittle substrate in the thickness direction along the groove line. With the crack line, below the groove line, the brittle substrate breaks a continuous connection in the direction intersecting the groove line.

e) Break the brittle substrate along the crack line.

Furthermore, the above-mentioned alphabetical characters "a)" ~ "e)" are used to distinguish the steps and are attached The addition does not imply the order of implementation of the steps.

According to the present invention, when the blade tip provided with the axially symmetrical front end is slid on one surface of the brittle substrate, the axial direction of the blade tip is perpendicular to one surface. Thereby, the part of the tip of the blade that is in direct contact with the brittle substrate is substantially included in the tip portion, and the relationship between the axial direction and the sliding direction becomes fixed without depending on the sliding direction. Therefore, there is no need to adjust the posture of the knife tip according to the sliding direction of the knife tip.

AL: auxiliary line

CL: Crack line

AX: axis direction

SF1: Upper surface (one side)

HR: High load range

LR: Low load zone

TL, TL1, TL2: groove line

4: Glass substrate (brittle substrate)

50, 150: cutting equipment

51, 151: knife point

51N, 151N, 151Na~151Nc, 151Ni~151Nk: tip

52: Support Department

Fig. 1 is a perspective view schematically showing the structure of a cutting tool used in the method of breaking a brittle substrate in the first embodiment of the present invention.

Fig. 2 is a side view schematically showing the structure of a cutting tool used in the method of breaking a brittle substrate in the first embodiment of the present invention.

Fig. 3 is a partial cross-sectional view of the vicinity of the front end of the tool tip of Figs. 1 and 2;

Fig. 4 is a flowchart schematically showing the structure of a method for breaking a brittle substrate in the first embodiment of the present invention.

Fig. 5 is a plan view schematically showing the first step of the method of breaking a brittle substrate in the first embodiment of the present invention.

Fig. 6 is a schematic end view taken along the line VI-VI of Fig. 5;

Fig. 7 is a plan view schematically showing the second step of the method of breaking a brittle substrate in the first embodiment of the present invention.

Fig. 8 is a schematic end view taken along the line VIII-VIII of Fig. 7;

Fig. 9 is a plan view schematically showing the first step of the method of breaking a brittle substrate in the second embodiment of the present invention.

FIG. 10 is a diagram illustrating the sliding direction of the blade tip on the brittle substrate in the step of FIG. 9.

Fig. 11 is a plan view schematically showing the second step of the method of breaking a brittle substrate in the second embodiment of the present invention.

Fig. 12 is a plan view schematically showing one step of the method of breaking a brittle substrate in the third embodiment of the present invention.

FIG. 13 is a diagram illustrating the sliding direction of the blade tip on the brittle substrate in the step of FIG. 12.

Fig. 14 is a plan view schematically showing the first step of the method of breaking a brittle substrate in the fourth embodiment of the present invention.

FIG. 15 is a diagram illustrating the sliding direction of the blade tip on the brittle substrate in the step of FIG. 14.

Fig. 16 is a plan view schematically showing the second step of the method of breaking a brittle substrate in the fourth embodiment of the present invention.

Fig. 17 is a plan view schematically showing one step of the method of breaking a brittle substrate in the fifth embodiment of the present invention.

FIG. 18 is a diagram illustrating the sliding direction of the blade tip on the brittle substrate in the step of FIG. 17.

Fig. 19 is a side view schematically showing one step of the method of breaking a brittle substrate in the sixth embodiment of the present invention.

Fig. 20 is a flowchart schematically showing a part of the method of breaking a brittle substrate in the seventh embodiment of the present invention.

Fig. 21 is a plan view schematically showing the first step of the method of breaking a brittle substrate in the eighth embodiment of the present invention.

Fig. 22 is a schematic end view taken along the line XXII-XXII of Fig. 21.

Fig. 23 is a plan view schematically showing the second step of the method of breaking a brittle substrate in the eighth embodiment of the present invention.

Fig. 24 is a plan view schematically showing the third step of the method of breaking a brittle substrate in the eighth embodiment of the present invention.

Fig. 25 is a flowchart schematically showing a part of the constitution of a method of breaking a brittle substrate in the ninth embodiment of the present invention.

Fig. 26 is a plan view schematically showing one step of the method of breaking a brittle substrate in the ninth embodiment of the present invention.

Fig. 27 is a schematic cross-sectional view taken along the line XXVII-XXVII of Fig. 26.

Fig. 28 is a schematic cross-sectional view taken along the line XXVIII-XXVIII of Fig. 26.

Fig. 29 is a schematic cross-sectional view taken along the line XXIX-XXIX of Fig. 26.

Fig. 30 is a plan view schematically showing one step of the method of breaking a brittle substrate in the ninth embodiment of the present invention.

Fig. 31 is a schematic cross-sectional view taken along the line XXXI-XXXI of Fig. 30.

Fig. 32 is a schematic cross-sectional view taken along the line XXXII-XXXII of Fig. 30.

Fig. 33 is a plan view schematically showing one step of the method of breaking a brittle substrate in the ninth embodiment of the present invention.

Fig. 34 is a schematic cross-sectional view taken along the line XXXIV-XXXIV of Fig. 33.

Fig. 35 is a schematic cross-sectional view taken along the line XXXV-XXXV of Fig. 33.

Fig. 36 is a plan view schematically showing one step of the method of breaking a brittle substrate in the ninth embodiment of the present invention.

Fig. 37 is a perspective view schematically showing the structure of a cutting tool used in the method of breaking a brittle substrate in the tenth embodiment of the present invention.

Fig. 38 is a schematic cross-sectional view taken along the line XXXVIII-XXXVIII of Fig. 37.

Fig. 39 is an example of the surface shape of the front end of the cutting edge along the line A-A of Fig. 38.

Fig. 40 is an example of the surface shape of the front end of the cutting edge along the line A-A of Fig. 38.

Hereinafter, an embodiment of the present invention will be described based on the drawings. Furthermore, the same or equivalent parts in the following drawings are marked with the same reference number and the description will not be repeated.

<Embodiment 1>

Each of FIGS. 1 and 2 is a perspective view schematically showing the configuration of the cutting tool 50 used in the method of dividing the glass substrate 4 (brittle substrate) in this embodiment. 3 is a partial cross-sectional view of the vicinity of the front end 51N of the tip 51 of FIGS. 1 and 2.

The cutting tool 50 has a blade tip 51 and a support part 52. The blade tip 51 and the supporting portion 52 may be a single piece composed of the same material.

As shown in FIG. 3, the tip 51 is provided with a front end 51N having axial symmetry in the axial direction AX. That is, the surface of the tip portion 51N is a surface obtained by rotating the curve around the axis direction AX. The surface of the front end portion 51N is a curved surface having a convex shape toward the outside. The surface of the front end 51N may be a part of a spherical surface. The radius of curvature of the tip portion 51N is preferably 3 μm or more and 40 μm or less. The surface of the front end 51N may also be a conical surface, and the apex of the conical surface may also be curved. The size of the tip portion 51N in the axial direction AX is typically 0.5 μm or more, and usually it is sufficient to be 1.0 μm or more, preferably 2.0 μm or more. Thereby, the tip 51 of the blade is aligned with the glass substrate 4 The part to be contacted is usually substantially contained in the front end portion 51N. Furthermore, the above-mentioned “axial symmetry” is preferably ideal geometrical axial symmetry, but it may also be a substantial axial symmetry in view of the effect on the glass substrate 4. The latter is referred to as "quasi-axial symmetry" in this specification, and its details are described in Embodiment 10 below.

It is preferable that the entire blade tip 51 including the tip portion 51N has axial symmetry in the axial direction AX. In FIG. 3, the tool tip 51 includes a right conical shape having axial symmetry in the axial direction AX, and a tip portion 51N is provided at the apex of the right conical shape. In the cross section including the axial direction AX (FIG. 3 ), if the shape of the tip portion 51N is ignored, the angle of the apex of the right cone shape is preferably 120° or more, more preferably 130° or more. Furthermore, the angle is preferably 160° or less, more preferably 150° or less.

The supporting portion 52 preferably extends in the axial direction AX. The entire cutting tool 50 may have axial symmetry in the axial direction AX.

Then, referring to the flowchart shown in FIG. 4, the method of dividing the glass substrate 4 will be described below.

In step S10 (FIG. 4), the glass substrate 4 to be split is prepared (FIG. 2). The glass substrate 4 has an upper surface SF1 (one surface), and a lower surface SF2 (the other surface) opposite to the upper surface SF1. The upper surface SF1 is provided with an edge ED. The upper surface SF1 is typically flat. In the example shown in FIG. 5, the edge ED has a rectangular shape. The glass substrate 4 has a thickness direction DT perpendicular to the upper surface SF1. In addition, in step S20 (FIG. 4), the above-mentioned cutting tool 50 (FIG. 1 to FIG. 3) having the blade tip 51 is prepared.

Referring to FIG. 5, by step S30 (FIG. 4), a trench line TL having a linear shape is formed. Specifically, perform the following steps.

First, the front end 51N of the blade tip 51 (FIGS. 1 to 3) is pressed against the upper surface SF1 at the position N1. As a result, the front end portion 51N is in contact with the glass substrate 4. As shown in the figure, the position N1 is preferably away from the edge ED of the upper surface SF1 of the glass substrate 4. In this case, it is avoided that the knife tip 51 collides with the edge ED of the upper surface SF1 of the glass substrate 4 when the knife tip 51 starts to slide.

Then, the axial direction AX of the cutting edge 51 is perpendicular to the upper surface SF1 of the glass substrate 4, and the front end 51N of the cutting edge 51 is slid on the upper surface SF1 (refer to the arrow in FIG. 5). When sliding, a load is applied to the blade edge 51 from the outside. The load direction is perpendicular to the upper surface SF1. Plastic deformation is generated on the upper surface SF1 by sliding.

By this plastic deformation, a groove line TL having a groove shape (refer to FIG. 6) is formed on the upper surface SF1 of the glass substrate 4. The trench line TL is obtained below the trench line TL, and the glass substrate 4 is continuously connected in the direction DC (FIG. 6) intersecting the extending direction of the trench line TL (the horizontal direction in FIG. 5). The way the crack state is formed. In a crack-free state, although the groove line TL obtained by plastic deformation is formed, the crack along the groove line TL is not formed. In order to obtain a crack-free state, the load applied to the cutting edge 51 is adjusted in such a way that the time point when the groove line TL is formed is smaller to the extent that no cracks are generated, and in the subsequent steps, the load is larger to generate formation energy. The degree of plastic deformation in the state of internal stress that produces cracks.

The groove line TL is preferably generated only by the plastic deformation of the glass substrate 4. In this case, no cutting is generated on the upper surface SF1 of the glass substrate 4. In order to avoid cutting, it is sufficient not to increase the load of the tool tip 51 excessively. By no cutting, it can avoid the generation of undesirable fine fragments on the upper surface SF1. However, light cutting is usually allowed.

The groove line TL is formed by sliding the front end 51N of the tip 51 from the position N1 to the position N3e through the position N2 due to the position N1 and the position N3e. Location N2 is far away from the edge ED of the upper surface SF1 of the glass substrate 4. The position N3e is located at the edge ED of the upper surface SF1 of the glass substrate 4. Therefore, the blade edge 51 slid to form the groove line TL finally reaches the position N3e. The crack-free state is maintained at the time point when the tool tip 51 is located at the position N2, and further, is maintained until the moment when the tool tip 51 reaches the position N3e. When the knife tip 51 reaches the position N3e, the knife tip 51 cuts off the edge ED of the upper surface SF1 of the glass substrate 4.

Referring to FIGS. 7 and 8, a fine crack is generated at the position N3e by the above-mentioned cutting. Taking the crack as a starting point, a crack is generated in a way to relieve the internal stress near the trench line TL. Specifically, the crack of the glass substrate 4 in the thickness direction DT extends along the groove line TL from the position N3e located at the edge ED of the upper surface SF1 of the glass substrate 4 (refer to the arrow in FIG. 7). In other words, the crack line CL starts to form. Thereby, as step S50 (FIG. 4), the crack line CL is formed from the position N3e to the position N1. The direction in which the crack line CL extends along the trench line TL (arrow in FIG. 7) is opposite to the direction in which the trench line TL is formed (arrow in FIG. 5).

Furthermore, in order to form the crack line CL more reliably, the speed at which the tool tip 51 slides from the position N2 to the position N3e can be made slower than the speed from the position N1 to the position N2. Similarly, the load applied to the tip 51 from the position N2 to the position N3e can be greater than the load from the position N1 to the position N2 in the range of maintaining a crack-free state.

With the crack line CL, below the trench line TL, the glass substrate 4 breaks a continuous connection in the direction DC (FIG. 8) intersecting the extending direction of the trench line TL (the horizontal direction in FIG. 7). The so-called "continuous connection" here means a connection that is not blocked by a crack. Furthermore, in the state where the continuous connection is broken as described above, the parts of the glass substrates 4 can contact each other through the cracks of the crack lines CL. In addition, a small amount of continuous connections may be left directly under the trench line TL.

Then, in step S60 (FIG. 4 ), the glass substrate 4 is divided along the crack line CL. That is, a so-called breaking step is performed. The breaking step can be performed by applying an external force to the glass substrate 4. For example, by facing the crack line CL on the upper surface SF1 of the glass substrate 4 (FIG. 8), a stress applying member (for example, a member called a "breaking rod") is pressed against the lower surface SF2, and the glass substrate 4 Apply stress to crack the crack of the crack line CL. Furthermore, when the crack line CL fully progresses in the thickness direction DT at the time of its formation, the formation of the crack line CL occurs simultaneously with the breaking of the glass substrate 4.

The glass substrate 4 is divided by the above steps. Furthermore, the step of forming the crack line CL described above is essentially different from the so-called breaking step. The breaking step is to completely separate the substrate by further extending the formed crack in the thickness direction. On the other hand, the formation step of the crack line CL is derived from the change from a crack-free state to a cracked state obtained by the formation of the trench line TL. It is believed that this change is caused by the release of internal stress in the crack-free state.

According to this embodiment, when the blade tip 51 with the front end 51N having axial symmetry slides on the upper surface SF1 of the glass substrate 4, the axial direction AX of the blade tip 51 is perpendicular to the upper surface SF1 (FIG. 2 ). In this way, the relationship between the axial direction AX and the sliding direction DA is fixed regardless of the direction DA in which the front end 51N of the cutting edge 51 slides. Therefore, there is no need to adjust the state of the tool tip 51 according to the sliding direction DA of the tool tip 51.

Furthermore, even in other embodiments described below, when the cutting edge 51 is slid on the upper surface SF1 of the glass substrate 4 in order to form the groove line TL, the axial direction AX of the cutting edge 51 is also perpendicular to the upper surface SF1. Therefore, even in other embodiments, the same effects as in this embodiment can be obtained.

<Embodiment 2>

In Embodiment 1, the trench line TL has a linear shape. In contrast, in this embodiment, the groove line TL includes a curved shape. Hereinafter, the steps of forming the trench line TL will be described in detail.

9, in this embodiment, the trench line TL has a curved shape. Correspondingly, the step of forming the groove line TL includes: sliding the front end 51N of the cutting edge 51 toward the direction DA1 (first direction); and then sliding the front end 51N toward the direction DA2 (second direction). step.

10, the direction DA2 is different from the direction DA1. In addition, the sliding direction DA of the front end 51N of the cutting edge 51 continuously changes between the direction DA1 and the direction DA2 as shown by the broken line in the figure.

Then, a crack line is formed along the trench line TL. 11, the glass substrate 4 is divided along the crack line.

In addition, the configuration other than the above is substantially the same as the configuration of the first embodiment described above, so the same or corresponding elements are given the same reference numerals, and the description thereof will not be repeated.

In this embodiment, the sliding direction DA changes between the direction DA1 and the direction DA2. Since the front end 51N of the tool tip 51 has axial symmetry, and the axis direction AX of the tool tip 51 is perpendicular to the upper surface SF1 (FIG. 2), the aforementioned change in the sliding direction DA does not affect the axis direction AX and the sliding direction DA relation. Therefore, there is no need to adjust the state of the tool tip 51 according to the sliding direction DA of the tool tip 51. In other words, even when the groove line TL including the curved portion is formed, there is no need to adjust the state of the blade edge 51 according to the sliding direction DA of the blade edge 51.

<Embodiment 3>

Referring to FIG. 12, in this embodiment, the trench line TL substantially includes a closed curve. Corresponding to this, as shown in FIG. 13, the sliding direction DA changes in all directions as shown by the dotted line in the figure. In other words, the front end 51N of the cutting edge 51 slides in all directions. In addition, since the configuration other than the above is substantially the same as the configuration of the above-mentioned second embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated.

<Embodiment 4>

14 and 15, in this embodiment, when the groove line TL is formed, the front end 51N of the blade edge 51 is in contact with the upper surface SF1 of the glass substrate 4, and the front end 51N faces the direction DA changes discontinuously from the direction DA1 to the direction DA2.

Then, a crack line is formed along the trench line TL. 16, the glass substrate 4 is divided along the crack line.

In addition, since the configuration other than the above is substantially the same as the configuration of the above-mentioned second embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated.

At the moment when the direction DA discontinuously changes, the blade edge 51 almost stops relatively relative to the glass substrate 4. In such a stopped state, if the state of the blade edge 51 is adjusted, the front end 51N of the blade edge 51 or the glass substrate 4 is likely to be damaged. According to this embodiment, since there is no need to adjust the state of the blade edge 51, the above-mentioned damage can be avoided.

<Embodiment 5>

Referring to FIG. 17, the trench line TL formed in this embodiment includes a trench line TL1 and a trench line TL2 that are parallel to each other. The trench line TL1 and the trench line TL2 are alternately formed. When the groove line TL1 is formed, the front end 51N of the blade edge 51 is brought into contact with the upper surface SF1 of the glass substrate 4, and the direction DA to which the front end 51N faces is the direction DA1. When forming the trench line TL2, one side The front end 51N of the blade edge 51 is brought into contact with the upper surface SF1 of the glass substrate 4, and the direction DA to which the front end 51N faces is the direction DA2. The direction DA1 is opposite to the direction DA2. Therefore, as shown in FIG. 18, the direction DA to which the tip portion 51N faces is either the direction DA1 or the direction DA2. In the formation of the groove line TL, the sliding direction DA changes discontinuously between the direction DA1 and the direction DA2.

In addition, since the configuration other than the above is substantially the same as the configuration of the fourth embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated.

If the two sides of the groove line TL1 and the groove line TL2 are formed by sliding in the direction DA1, the cutting edge 51 is moved from one edge (the left edge in the figure) to the other edge (the right side in the figure). After the edge) is moved to form the groove line TL1, it is necessary to perform an operation only for returning the cutting edge 51 to the one edge side. In contrast, according to this embodiment, the trench line TL2 is formed in this operation. This shortens the time required for the steps. Therefore, productivity can be improved.

<Embodiment 6>

19, in each of the above-mentioned embodiments, when the groove line TL is formed, the blade edge 51 may be rotated around the axial direction AX (refer to the figure, the rotation RT). The rotation RT can also be performed on the upper surface SF1 of the glass substrate 4 while sliding the front end 51N of the blade edge 51. Rotating RT can also be always performed during sliding or intermittently. Alternatively, the rotation RT may be performed on the upper surface SF1 of the glass substrate 4 without sliding the front end 51N of the blade edge 51. In this case, the knife edge 51 is rotated in a state where the knife edge 51 is stopped or in a state where the knife edge 51 is away from the glass substrate 4.

According to the present embodiment, local wear of the tool tip 51 is avoided. Therefore, the life of the tool tip 51 can be extended.

<Embodiment 7>

In each of the above embodiments, when the groove line TL is formed, a lubricant may be supplied to the position where the front end 51N of the blade edge 51 slides on the upper surface SF1 of the glass substrate 4. In other words, the step of forming the groove line TL (FIG. 4: step S30 ), as shown in FIG. 20, may include the step S31 of supplying lubricant and the step S32 of sliding the tool tip 51 at the position where the lubricant is supplied. As the lubricant, for example, a liquid lubricant at room temperature or a solid lubricant at room temperature can be used.

In each of the above embodiments, when the groove line TL is formed, the blade edge 51 sliding on the upper surface SF1 of the glass substrate 4 is easily worn. According to this embodiment, such abrasion can be suppressed.

<Embodiment 8>

Referring to Fig. 21, in step S10 (Fig. 4), the same glass substrate 4 as in the first embodiment described above is prepared. However, in this embodiment, the auxiliary line AL is provided in advance on the upper surface SF1 of the glass substrate 4. Referring to FIG. 22, the auxiliary line AL has an auxiliary trench line TLa and an auxiliary crack line CLa. The auxiliary trench line TLa has a groove shape. The auxiliary crack line CLa is formed by extending the crack of the glass substrate 4 in the thickness direction DT along the auxiliary trench line TLa.

In this embodiment, the auxiliary line AL is provided by the step of simultaneously forming the auxiliary trench line TLa and the auxiliary crack line CLa on the upper surface SF1 of the glass substrate 4. Such auxiliary line AL can be formed by a conventional typical scribing method. For example, such auxiliary line AL, as indicated by the arrow in FIG. 21, can be formed by a knife tip straddling the edge ED of the upper surface SF1 of the glass substrate 4 and then moving on the upper surface SF1. The tip of the blade is preferably a rotatably held (wheel-shaped one). In other words, the tip of the knife is preferably one that does not slide on the glass substrate 4 but rotates on the glass substrate 4.

Furthermore, the starting point of the auxiliary line AL is the edge ED in FIG. 21, but it can also be far away from the edge ED. In addition, the auxiliary line AL can be formed by the same method as the formation method of the crack line CL in any one of the above-mentioned embodiments 1 to 7. Also, it can also be used to slide on the glass substrate 4 The tip of the knife forms the aforementioned auxiliary line AL. Alternatively, in order to easily prepare the blade tip for the auxiliary thread AL, the auxiliary thread AL may be formed by using the blade tip 51.

Next, in step S20 (FIG. 4 ), the cutting edge 51 which is the same as that of the first embodiment is prepared.

Referring to FIG. 23, then, a trench line TL is formed in step S30 (FIG. 4). In this embodiment, the groove line TL is formed by sliding the tool tip 51 from the position N1 to the position N3a through the position N2 due to the position N1 and the position N3a. The position N3a is arranged on the auxiliary line AL. The position N2 is arranged between the position N1 and the position N3a. Preferably, the tip 51 exceeds the position N3a on the auxiliary line AL and then slides to the position N4. The position N4 is preferably away from the edge ED.

The cutting edge 51 for forming the groove line TL and sliding as described above crosses the auxiliary line AL at the position N3a. By this intersection, a fine crack is generated at the position N3a. Taking the crack as a starting point, a crack is generated in a way to relieve the internal stress near the trench line TL. Specifically, the crack of the glass substrate 4 in the thickness direction extends along the groove line TL from the position N3a on the auxiliary line AL (refer to the arrow in FIG. 24). In other words, the crack line CL starts to form (FIG. 24). Thereby, as step S50 (FIG. 4), the crack line CL is formed from the position N3a to the position N1.

After the blade edge 51 reaches the position N3a, it moves away from the glass substrate 4. Preferably, the knife tip 51 moves beyond the position N3a to the position N4 and then moves away from the glass substrate 4.

Then, in step S60 (FIG. 4 ), as in the first embodiment, the glass substrate 4 is divided along the crack line CL. The cutting method of the glass substrate 4 of this embodiment is performed through the above steps.

In Embodiment 1, the cutting edge 51 cuts the glass substrate 4 at the position N3e (FIG. 5). In contrast, according to the present embodiment, such cutting is unnecessary. In this way, the damage to the blade tip 51 or the glass substrate 4 that may occur when the blade tip 51 is used for cutting can be avoided.

Furthermore, there may be cases where the starting point of the formation of the crack line CL cannot be obtained simply by crossing the cutting edge 51 with the auxiliary line AL. In this case, after the trench line TL crossing the auxiliary line AL is formed, the glass substrate 4 can be divided along the auxiliary line AL. Thereby, an opportunity to start the formation of the crack line CL can be obtained.

<Embodiment 9>

Referring to Fig. 26, first, as in the other embodiments, a glass substrate 4 is prepared (Fig. 4: step S10). In addition, the tool tip 51 is prepared (FIG. 4: Step S20).

Then, as in the other embodiments, the axial direction AX of the cutting edge 51 is perpendicular to the upper surface SF1 of the glass substrate 4, and the front end 51N of the cutting edge 51 is slid on the upper surface SF1. This sliding progresses from the start point N1 to the end point N3 via the halfway point N2. As a result, plastic deformation is generated on the upper surface SF1 of the glass substrate 4. As a result, a trench line TL extending from the start point N1 to the end point N3 through the midway point N2 is formed on the upper surface SF1 (FIG. 4: step S30).

The step of forming each of the trench lines TL includes a step of forming a low-load section LR as a part of the trench line TL (FIG. 25: step S30L), and a step of forming a high-load section HR as a part of the trench line TL (FIG. 25: Step S30H). In FIG. 26, a low-load section LR is formed from the start point N1 to the midway point N2, and a high-load section HR is formed from the midway point N2 to the end point N3. The load applied to the cutting edge 51 in the step of forming the high-load section HR is higher than the load used in the step of forming the low-load section LR. On the contrary, the load applied to the cutting edge 51 in the step of forming the low-load section LR is lower than the load used in the step of forming the high-load section HR, for example, it is about 30-50% of the load in the high-load section HR . Therefore, the width of the groove line in the high-load section HR is lower and the width of the load section LR is larger. Also, as shown in FIG. 27, the depth of the high load zone HR is lower and the depth of the load zone LR is larger. The profile of the groove line TL For example, there is a V shape with an angle of about 150°.

Furthermore, since a high load is applied to the cutting edge 51 in the high load interval HR, considering the life of the cutting edge 51, the distance of the high load interval HR is preferably smaller. Furthermore, when the load is changed in the formation of the trench line TL, since the load in the high-load section HR is sufficiently increased at a smaller distance, it is preferable to reduce the scribing speed in the high-load section HR. That is, since it is difficult to control the instantaneous increase in the load of the cutting edge 51, in fact, starting from the position N2, the load is increased in a fixed section until the load reaches a predetermined load, and then scribing is performed. Therefore, by reducing the speed in the high-load section HR, a high load can be formed at a smaller distance, and the overall distance of the high-load section HR can be reduced.

The step of forming the trench line TL is to obtain a state in which the glass substrate 4 is continuously connected in the direction DC (FIG. 28 and FIG. 29) intersecting the trench line TL directly under the trench line TL, that is, the state without cracks. Way. Therefore, the load applied to the tip of the blade is so large that the glass substrate 4 is plastically deformed, and is so small that cracks starting from the plastic deformation portion are not generated.

Then, the step of forming the crack line (FIG. 4: Step S50) is performed in the following manner.

Referring to FIGS. 30 to 32, first, on the upper surface SF1 of the glass substrate 4, an auxiliary line AL that intersects the high-load section HR is formed. The auxiliary line AL is accompanied by cracks penetrating in the thickness direction of the glass substrate 4. The auxiliary line AL can be formed by a usual scribing method.

Then, the glass substrate 4 is separated along the auxiliary line AL. The separation can be performed by the usual breaking step. Taking this separation as an opportunity, the cracks of the glass substrate 4 in the thickness direction are along the groove line TL, and the groove line TL only extends to the high load interval HR.

33 and 34, through the above steps, along a part of the trench line TL A crack line CL is formed. Specifically, in the high-load section HR, a crack line CL is formed between the side newly generated by the separation and the halfway point N2. The direction in which the crack line CL is formed is opposite to the direction DA in which the trench line TL is formed (FIG. 26).

Furthermore, it is difficult to form a crack line CL in the portion between the side newly generated by the separation and the end point N3. It is presumed that the reason is that the distribution of internal stress generated near the trench line TL has anisotropy depending on the formation direction of the trench line TL.

35, by the crack line CL, the glass substrate 4 is disconnected from the continuous connection in the direction DC intersecting the extending direction of the trench line TL directly under the high load section HR of the trench line TL. The so-called "continuous connection" here, in other words, means a connection that is not covered by a crack. Furthermore, as described above, in the state where the continuous connection is broken, the parts of the glass substrates 4 can be in contact with each other through the cracks of the crack lines CL.

Then, a breaking step of breaking the glass substrate 4 along the trench line TL is performed (FIG. 4: step S60). At this time, by applying stress to the glass substrate 4, the crack extends along the low-load section LR starting from the crack line CL. The direction in which the crack extends (arrow PR in FIG. 36) is opposite to the direction DA in which the trench line TL is formed (FIG. 26).

The glass substrate 4 is broken by the above steps.

According to this embodiment, when the groove line TL (FIG. 26 and FIG. 27) is formed to define the position where the glass substrate 4 is broken, compared with the high-load section HR, the application to the cutting edge 51 in the low-load section LR is reduced. (Figure 1) the load. Therefore, damage to the tip 51 can be reduced.

In addition, when the low-load section LR in the low-load section LR and the high-load section HR is in a crack-free state (FIGS. 33 and 34 ), the low-load section LR does not have a crack that becomes the starting point for breaking the glass substrate 4. Therefore, in this state, the glass substrate 4 is arbitrarily processed At this time, even if unexpected stress is applied to the low-load section LR, it is difficult to cause unintentional breaking of the glass substrate 4. Therefore, the above treatment can be performed stably.

In addition, when both the low-load section LR and the high-load section HR are in a crack-free state (FIGS. 26 and 27 ), the groove line TL does not have a crack that becomes the starting point for breaking the glass substrate 4. Therefore, when the glass substrate 4 is arbitrarily processed in this state, even if an unexpected stress is applied to the trench line TL, it is difficult to cause unintentional disconnection of the glass substrate 4. Therefore, the above treatment can be performed more stably.

In addition, the trench line TL is formed before the formation of the auxiliary line AL. In this way, the influence of the auxiliary line AL during the formation of the trench line TL can be avoided. In particular, it can be avoided that an abnormality is formed immediately after the cutting edge 51 passes on the auxiliary line AL in order to form the groove line TL.

<Embodiment 10>

In this embodiment, the case where the front end of the tool tip has the quasi-axial symmetry mentioned in the first embodiment will be described.

Fig. 37 is a perspective view schematically showing the configuration of the cutting tool 150 in this embodiment. The cutting tool 150 has a blade tip 151 provided with a tip portion 151N instead of the blade tip 51 provided with a tip portion 51N (FIG. 2 ). The tip 151 has the shape of a polygonal pyramid with a curved vertex. The polygonal pyramid has a side surface SD and a ridge line RG. The apex of the polygonal pyramid is provided with a front end 151N.

Fig. 38 is a schematic cross-sectional view taken along the line XXXVIII-XXXVIII of Fig. 37 and perpendicular to the axis direction AX. The line XXXVIII-XXXVIII (FIG. 37) corresponds to the cross section perpendicular to the axis direction AX near the boundary between the front end 151N of the tip 151 and the other parts. Hereinafter, the shape of the front end 151N in the cross-sectional observation will be described.

The shape of the front end 151N is an n-sided polygon (n ≧3), preferably a regular polygon. A 16-sided polygon (n=16) is illustrated in FIG. 38. The tip portion 151N has n points PT corresponding to n ridge lines RG (FIG. 37 ), and each of the points PT is tangent to the circumscribed circle CC. In addition, the front end portion 151N has n sides SD corresponding to n side surfaces SD (FIG. 37 ), and each of the sides SD has a size DS. The size of the circumscribed circle CC is fixed. The larger the n, the smaller the size DS. As a result, the cross-sectional shape of the tip portion 151N is closer to a circle. Therefore, the larger n is, the closer the axial symmetry in the axial direction AX of the front end portion 151N is to the ideal geometric symmetry. Therefore, the larger n is to some extent, the more axisymmetrical the front end portion 151N is. That is, the tip portion 151N can be said to have the above-mentioned quasi-axial symmetry. According to the research of the present inventor, if the size DS is 1 μm or less, it can be said that the tip portion 151N has quasi-axial symmetry. The n that satisfies this condition can be calculated based on, for example, the angle of the front end 151N and the radius of curvature of the front end 151N near the axis AX. An example of this calculation will be described below.

FIG. 39 corresponds to the cross-sectional view taken along the line A-A of FIG. 38. As an example of the tip portion 151N, it shows the surface shape of the tip portion 151Na~151Nc near the axis AX with the radius of curvature R=3μm. Each of the tip portions 151Na to 151Nc has tip angles of 120°, 130°, and 140°. Since the radius of curvature R near the axis AX is 3 μm, when the size of the tip portion 51N in the axial direction AX is 1 μm, each of the tip portions 151Na to 151Nc has a diameter of 5.08 μm, 5.62 μm, and 6.56 μm. In other words, each of the tip portions 151Na to 151Nc has a circumference of 15.96 μm, 17.65 μm, and 20.60 μm. Therefore, when the size DS (FIG. 38) is set to 1 μm or less, n is 16 or more in the case of the tip portion 151Na, 18 or more in the case of the tip portion 151Nb, and 21 or more in the case of the tip portion 151Nc.

Fig. 40 corresponds to the cross-sectional view taken along the line A-A of Fig. 38. As an example of the front end portion 151N, the front end portion 151Ni has a radius of curvature R=5μm near the axis AX. ~151Nk surface shape. Each of the tip portions 151Ni to 151Nk has tip angles of 120°, 130°, and 140°. Since the radius of curvature R near the axis AX is 5 μm, when the size of the tip portion 51N in the axial direction AX is 1 μm, each of the tip portions 151Ni to 151Nk has diameters of 6.17 μm, 6.51 μm, and 7.26 μm. In other words, each of the tip portions 151Ni to 151Nk has a circumference of 19.38 μm, 20.45 μm, and 22.80 μm. Therefore, when the size DS (FIG. 38) is set to 1 μm or less, n is 20 or more in the case of the tip portion 151Ni, 21 or more in the case of the tip portion 151Nj, and 23 or more in the case of the tip portion 151Nk.

According to the research results of Fig. 39 and Fig. 40, for example, if n≧16, quasi-axial symmetry may be obtained. Therefore, n is preferably 16 or more. If n≧25, any front end angle and radius of curvature within the usual range can be used to obtain quasi-axial symmetry. In view of the workability and processing time of the work for forming the front end portion, n is preferably not too large, and therefore n is preferably 25 or less.

In order to obtain the cutting edge 151, for example, the front end of a material piece having a polygonal prism shape (for example, a diamond piece) may be polished multiple times, and the front end of the diamond piece may be given a substantially polygonal pyramid shape. As a modified example, the ridge line RG (FIG. 37) may be rounded. As a result, since the straight portion of the side SD (FIG. 38) becomes shorter, the shape of the tip portion 151N is closer to a circle. That is, the axial symmetry of the tip portion 151N is closer to ideal axial symmetry. In this case, even a smaller n can obtain quasi-axial symmetry.

In addition, in each of the above-mentioned embodiments, the case where the edge of the upper surface SF1 has a rectangular shape is illustrated, but other shapes may also be used. In addition, it is explained that there is a case where the upper surface SF1 is flat, but the upper surface may be curved. In addition, although the groove line TL is described as a straight line, the groove line TL may also be curved. Also, explain the case where the glass substrate 4 is used as a brittle substrate, but the brittle base The plate can also be made of brittle materials other than glass, for example, it can be made of ceramic, silicon, compound semiconductor, sapphire or quartz.

4‧‧‧Glass substrate (brittle substrate)

50‧‧‧Cutting equipment

51‧‧‧Knife Point

51N‧‧‧Front end

52‧‧‧Support Department

AX‧‧‧Axis direction

SF1‧‧‧Upper surface (one side)

SF2‧‧‧Lower surface (the other side)

ED‧‧‧Edge

DA‧‧‧Slide direction

DT‧‧‧Thickness direction

Claims (9)

A method for breaking a brittle substrate, comprising the following steps: a) preparing a brittle substrate having one side and a thickness direction perpendicular to the above-mentioned side; and b) preparing a front end with axial symmetry in the axial direction The step of cutting edge; further c) making the axial direction of the cutting edge perpendicular to the one surface of the brittle substrate, and sliding the front end portion of the cutting edge on the one surface, thereby on the one surface of the brittle substrate In the above step of forming groove lines with a groove shape by plastic deformation, the groove lines are formed in such a way as to obtain the following state: below the groove lines, the brittle substrate is in the direction intersecting the groove lines The state of continuous connection is the state without cracks, and further d) the step of forming crack lines by extending the cracks of the brittle substrate in the thickness direction along the groove lines, and forming the crack lines by the crack lines. Below, the brittle substrate is disconnected in a continuous connection in the direction crossing the groove line; further e) the step of breaking the brittle substrate along the crack line; the front end of the blade tip has a radius of curvature of 3 μm Above and below 40μm, the dimension along the axis is above 0.5μm. For example, the method for breaking a brittle substrate in the first item of the patent application, wherein the above step c) includes: c1) the step of sliding the front end of the tool tip toward the first direction; c2) after the above step c1), the above The step of sliding the tip of the knife tip toward a second direction that is different from the first direction. For example, the method for breaking a brittle substrate in the second item of the scope of the patent application, wherein the step c) includes the following steps: while contacting the front end portion of the blade tip with the one surface of the brittle substrate, The direction in which the tip portion faces changes discontinuously from the first direction to the second direction. For example, the method for breaking a brittle substrate in the scope of the patent application, wherein in the above step c), the front end of the knife tip slides in all directions. For example, the method for breaking a brittle substrate according to any one of items 1 to 4 in the scope of the patent application, wherein the tool tip includes a straight cone shape having axisymmetrical properties in the axial direction, and the front end portion of the tool tip is disposed on the above The apex of a straight cone shape. For example, the method for breaking a brittle substrate according to any one of items 1 to 4 in the scope of the patent application, wherein the step c) includes the following steps: rotating the tool tip around the axis direction. For example, the method for breaking a brittle substrate in the scope of the patent application, wherein the step of rotating the blade tip around the axis direction includes the following steps: sliding the front end portion of the blade tip on the one side of the brittle substrate While rotating the blade tip around the axis direction. For example, the method of breaking a brittle substrate in the scope of the patent application, wherein the step of rotating the tool tip around the axis direction includes the following steps: on the one side of the fragile substrate, the front end of the tool tip does not slide The tool tip is rotated around the axis direction. For example, the method for breaking a brittle substrate according to any one of items 1 to 4 in the scope of the patent application, wherein the step c) includes the following steps: sliding the position of the front end of the knife tip on the one side of the brittle substrate Supply lubricant.

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