WO2017204055A1

WO2017204055A1 - Brittle substrate cutting method

Info

Publication number: WO2017204055A1
Application number: PCT/JP2017/018536
Authority: WO
Inventors: 曽山　浩; 淳史井村
Original assignee: 三星ダイヤモンド工業株式会社
Priority date: 2016-05-25
Filing date: 2017-05-17
Publication date: 2017-11-30
Also published as: CN109219505A; KR102167941B1; TWI740945B; KR20180136528A; TW201808840A; CN109219505B; JP6645577B2; JPWO2017204055A1

Abstract

A cutting edge (51) provided with a distal end section (51N) having axial symmetry in an axial direction (AX) is prepared. While orienting the axial direction (AX) of the cutting edge (51) so as to be perpendicular to one surface (SF1) of a brittle substrate (4), the distal end section (51N) of the cutting edge (51) is moved on the one surface (SF1) in a sliding manner, thereby forming a trench line in a crack-free state. A crack line is formed by extending a crack in the brittle substrate (4) along the trench line (TL) in a thickness direction (DT). The brittle substrate (4) is cut along the crack line.

Description

Method for dividing brittle substrate

The present invention relates to a method for dividing a brittle substrate.

In the manufacture of electrical devices such as flat display panels or solar cell panels, it is often necessary to break the brittle substrate. In a typical cutting method, first, a crack line is formed on a brittle substrate. In this specification, “crack line” means that a crack partially progressing in the thickness direction of the brittle substrate extends in a line shape on the surface of the brittle substrate. Next, a so-called break process is performed. Specifically, by applying a stress to the brittle substrate, the cracks in the crack line are completely advanced in the thickness direction. Thereby, a brittle board | substrate is parted along a crack line.

According to Patent Document 1, a depression on the upper surface of a glass plate is generated during scribing. In this Patent Document 1, this indentation is referred to as a “scribe line”. Further, simultaneously with the engraving of the scribe line, a crack extending in the downward direction from the scribe line is generated. As can be seen from the technique of Patent Document 1, in the conventional typical technique, the crack line is formed simultaneously with the formation of the scribe line.

According to Patent Document 2, a cutting technique that is significantly different from the above-described typical cutting technique has been proposed. According to this technique, first, by generating plastic deformation by sliding the blade edge on the brittle substrate, a groove shape called “scribe line” in Patent Document 2 is formed. Hereinafter, this groove shape is referred to as a “trench line”. At the time when the trench line is formed, no crack is formed below the trench line. Then, the crack line is formed by extending the crack along the trench line. That is, unlike a typical technique, a trench line without a crack is once formed, and then a crack line is formed along the trench line. Thereafter, a normal breaking process is performed along the crack line.

The trench line without cracks used in the technique of Patent Document 2 can be formed by sliding the blade edge with a lower load than a typical scribe line with simultaneous crack formation. When the load is small, the damage applied to the cutting edge is reduced. Therefore, according to this cutting technique, the life of the cutting edge can be extended.

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

JP-A-9-188534 International Publication No. 2015/151755

According to Patent Document 2, the direction in which the axial direction is projected onto the glass substrate corresponds to the sliding direction of the blade edge. In other words, there is anisotropy in the action of the substrate edge on the brittle substrate. For this reason, it is necessary to adjust an axial direction corresponding to the sliding direction of a blade edge | tip. Therefore, it is necessary to provide a mechanism for adjusting the posture of the blade edge in the brittle substrate cutting apparatus so that the axial direction corresponds to the sliding direction. In particular, when the sliding direction of the cutting edge is not constant, it is necessary to provide a mechanism for controlling the attitude of the cutting edge. The necessity of adjusting and controlling the posture of the cutting edge can lead to disadvantages such as an increase in the cost of the cutting device, an increase in time required for the process, and a decrease in the accuracy of the scribe position.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a method for cutting a brittle substrate that does not require adjustment of the posture of the blade edge according to the sliding direction of the blade edge. It is.

The method for cutting a brittle substrate according to one aspect of the present invention includes the following steps a) to e).
a) A brittle substrate having one surface and a thickness direction perpendicular to the one surface is prepared.
b) A cutting edge provided with a tip having axial symmetry in the axial direction is prepared.
c) By sliding the tip of the blade edge on one surface while making the axial direction of the blade edge perpendicular to one surface of the brittle substrate, the trench line having a groove shape is deformed by one of the brittle substrates by plastic deformation. Formed on the surface. The trench line is formed so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the trench line below the trench line.
d) A crack line is formed by extending a crack of the brittle substrate in the thickness direction along the trench line. The brittle substrate is disconnected continuously in the direction crossing the trench line below the trench line by the crack line.
e) The brittle substrate is divided along the crack line.

Note that the alphabet letters “a)” to “e)” above are attached to distinguish the processes, and do not imply the order of execution of the processes.

According to the present invention, when the cutting edge provided with the tip portion having axial symmetry is slid on one surface of the brittle substrate, the axial direction of the cutting edge is perpendicular to the one surface. As a result, the relationship between the axial direction and the sliding direction is constant without depending on the sliding direction. Therefore, it is not necessary to adjust the posture of the blade edge according to the sliding direction of the blade edge.

It is a perspective view which shows roughly the structure of the cutting tool used for the cutting method of the brittle board | substrate in Embodiment 1 of this invention. It is a side view which shows roughly the structure of the cutting tool used for the cutting method of the brittle board | substrate in Embodiment 1 of this invention. It is a fragmentary sectional view of the vicinity of the front-end | tip part of the blade edge | tip of FIG. 1 and FIG. It is a flowchart which shows schematically the structure of the brittle board | substrate parting method in Embodiment 1 of this invention. It is a top view which shows roughly the 1st process of the cutting method of a brittle board | substrate in Embodiment 1 of this invention. FIG. 6 is a schematic end view taken along line VI-VI in FIG. 5. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 1 of this invention. FIG. 8 is a schematic end view taken along line VIII-VIII in FIG. 7. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate in Embodiment 2 of this invention. It is a figure explaining the sliding direction of the blade edge | tip on a brittle board | substrate in the process of FIG. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 2 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 3 of this invention. It is a figure explaining the sliding direction of the blade edge | tip on a brittle board | substrate in the process of FIG. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate in Embodiment 4 of this invention. It is a figure explaining the sliding direction of the blade edge | tip on a brittle board | substrate in the process of FIG. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 4 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 5 of this invention. It is a figure explaining the sliding direction of the blade edge | tip on a brittle board | substrate in the process of FIG. It is a side view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 6 of this invention. It is a flowchart which shows roughly the partial structure of the cutting method of a brittle board | substrate in Embodiment 7 of this invention. It is a top view which shows roughly the 1st process of the cutting method of a brittle board | substrate in Embodiment 8 of this invention. FIG. 22 is a schematic end view taken along line XXII-XXII in FIG. 21. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 8 of this invention. It is a top view which shows roughly the 3rd process of the cutting method of a brittle board | substrate in Embodiment 8 of this invention. It is a flowchart which shows schematically the partial structure of the cutting method of a brittle board | substrate in Embodiment 9 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 9 of this invention. FIG. 27 is a schematic cross-sectional view taken along line XXVII-XXVII in FIG. 26. FIG. 27 is a schematic sectional view taken along line XXVIII-XXVIII in FIG. 26. FIG. 27 is a schematic cross-sectional view taken along line XXIX-XXIX in FIG. 26. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 9 of this invention. FIG. 31 is a schematic cross-sectional view taken along line XXXI-XXXI in FIG. 30. FIG. 31 is a schematic cross-sectional view taken along line XXXII-XXXII in FIG. 30. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 9 of this invention. FIG. 34 is a schematic cross-sectional view taken along line XXXIV-XXXIV in FIG. 33. FIG. 34 is a schematic cross-sectional view taken along line XXXV-XXXV in FIG. 33. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 9 of this invention. It is a perspective view which shows roughly the structure of the cutting instrument used for the cutting method of the brittle board | substrate in Embodiment 10 of this invention. FIG. 38 is a schematic sectional view taken along line XXXVIII-XXXVIII in FIG. 37. FIG. 39 is an example of the surface shape of the tip of the blade edge along line AA in FIG. FIG. 39 is an example of the surface shape of the tip of the blade edge along line AA in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

<Embodiment 1>
Each of FIG. 1 and FIG. 2 is a perspective view schematically showing a configuration of a cutting instrument 50 used in the method for cutting glass substrate 4 (brittle substrate) in the present embodiment. FIG. 3 is a partial cross-sectional view of the vicinity of the tip 51N of the blade edge 51 of FIGS.

The cutting instrument 50 has a cutting edge 51 and a support part 52. The cutting edge 51 and the support portion 52 may be an integral member made of the same material.

As shown in FIG. 3, the blade edge 51 is provided with a tip 51N having axial symmetry in the axial direction AX. That is, the surface of the tip 51N is a surface obtained by rotating a curve around the axial direction AX. The surface of the tip 51N is a curved surface having a convex shape toward the outside. The surface of the tip 51N may be a part of a spherical surface. The radius of curvature of the tip 51N is preferably 3 μm or more and 40 μm or less. The surface of the tip 51N may be a conical surface, and the apex of this conical surface may be rounded. The dimension of the tip 51N along the axial direction AX is typically 0.5 μm or more, and usually 1.0 μm or more is sufficient, and preferably 2.0 μm or more. Thereby, the part which will contact the glass substrate 4 directly among the blade edge | tips 51 is normally substantially contained in the front-end | tip part 51N. The “axial symmetry” described above is preferably ideal geometric axial symmetry, but may be substantial axial symmetry in view of the action on the glass substrate 4. The latter is referred to as “pseudo axial symmetry” in the present specification, and details thereof will be described in a tenth embodiment to be described later.

Preferably, the entire cutting edge 51 including the tip 51N has axial symmetry in the axial direction AX. In FIG. 3, the blade edge 51 includes a right cone shape having axial symmetry in the axial direction AX, and a tip 51N is provided at the apex of the right cone shape. In the cross section including the axial direction AX (FIG. 3), if the shape of the tip 51N is ignored, the angle of the apex of the right cone shape is preferably 120 ° or more, and more preferably 130 ° or more. Moreover, this angle is preferably 160 ° or less, and more preferably 150 ° or less.

The support part 52 preferably extends along the axial direction AX. The entire cutting instrument 50 may have axial symmetry in the axial direction AX.

Next, a method for dividing the glass substrate 4 will be described below with reference to the flowchart shown in FIG.

In step S10 (FIG. 4), a glass substrate 4 (FIG. 2) to be divided is prepared. The glass substrate 4 has an upper surface SF1 (one surface) and an opposite lower surface SF2 (other surface). An edge ED is provided on the upper surface SF1. 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 step S20 (FIG. 4), the above-described cutting tool 50 (FIGS. 1 to 3) having the blade edge 51 is prepared.

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

First, the tip 51N of the blade edge 51 (FIGS. 1 to 3) is pressed against the upper surface SF1 at the position N1. As a result, the tip 51N comes into contact with the glass substrate 4. The position N1 is preferably away from the edge ED of the upper surface SF1 of the glass substrate 4 as shown. In that case, it is possible to avoid the cutting edge 51 from colliding with the edge ED of the upper surface SF <b> 1 of the glass substrate 4 at the start of sliding of the cutting edge 51.

Next, the tip 51N of the blade edge 51 is slid on the upper surface SF1 while making the axial direction AX of the blade edge 51 perpendicular to the upper surface SF1 of the glass substrate 4 (see the arrow in FIG. 5). A load is applied to the blade edge 51 from the outside during sliding. This load direction is perpendicular to the upper surface SF1. Plastic deformation is generated on the upper surface SF1 by sliding.

The trench line TL having a groove shape (see FIG. 6) is formed on the upper surface SF1 of the glass substrate 4 by this plastic deformation. The trench line TL is a crackless state in which the glass substrate 4 is continuously connected in the direction DC (FIG. 6) intersecting the extending direction (lateral direction in FIG. 5) of the trench line TL below the trench line TL. It is formed so that a state is obtained. In the crackless state, the trench line TL is formed by plastic deformation, but no crack is formed along the trench line TL. In order to obtain a crackless state, the load applied to the cutting edge 51 is so small that cracks do not occur at the time of forming the trench line TL, and creates an internal stress state that can generate cracks in a later process. It is adjusted so as to be large enough to cause plastic deformation.

The trench line TL is preferably generated only by plastic deformation of the glass substrate 4, and in this case, no scraping occurs on the upper surface SF <b> 1 of the glass substrate 4. In order to avoid cutting, the load on the blade edge 51 should not be excessively increased. By not scraping, it is possible to avoid undesirable fine fragments on the upper surface SF1. However, some shaving is usually acceptable.

The formation of the trench line TL is performed between the position N1 and the position N3e by sliding the tip 51N of the blade edge 51 from the position N1 to the position N3e via the position N2. The position N2 is 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 trench line TL finally reaches the position N3e. The crackless state is maintained when the cutting edge 51 is located at the position N2, and further maintained until the moment when the cutting edge 51 reaches the position N3e. When the blade edge 51 reaches the position N3e, the blade edge 51 cuts down the edge ED of the upper surface SF1 of the glass substrate 4.

Referring to FIG. 7 and FIG. 8, the above-mentioned cut-down causes a fine breakage at position N3e. Starting from this breakdown, a crack is generated so as to release the internal stress in the vicinity of the trench line TL. Specifically, a crack in the glass substrate 4 in the thickness direction DT extends from the position N3e located at the edge ED of the upper surface SF1 of the glass substrate 4 along the trench line TL (see the arrow in FIG. 7). In other words, the formation of the crack line CL is started. 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).

In order to make the formation of the crack line CL more reliable, the speed at which the blade edge 51 slides from the position N2 to the position N3e may be smaller than the speed from the position N1 to the position N2. Similarly, the load applied to the blade edge 51 from the position N2 to the position N3e may be larger than the load from the position N1 to the position N2 within a range in which the crackless state is maintained.

The continuous connection is broken in the direction DC (FIG. 8) where the glass substrate 4 intersects the extending direction (lateral direction in FIG. 7) of the trench line TL below the trench line TL by the crack line CL. Here, “continuous connection” means a connection that is not interrupted by a crack. In addition, in the state where the continuous connection is cut as described above, the portions of the glass substrate 4 may be in contact with each other through the cracks of the crack line CL. Further, a slightly continuous connection may be left immediately below the trench line TL.

Next, in step S60 (FIG. 4), the glass substrate 4 is divided along the crack line CL. That is, a so-called break process is performed. The breaking process can be performed by applying an external force to the glass substrate 4. For example, by pressing a stress applying member (for example, a member called “break bar”) on the lower surface SF2 toward the crack line CL (FIG. 8) on the upper surface SF1 of the glass substrate 4, cracks in the crack line CL are obtained. Is applied to the glass substrate 4. When the crack line CL is completely advanced in the thickness direction DT at the time of formation, the formation of the crack line CL and the division of the glass substrate 4 occur simultaneously.

Thus, the glass substrate 4 is divided. Note that the crack line CL forming process described above is essentially different from a so-called break process. In the breaking process, the already formed cracks are further extended in the thickness direction to completely separate the substrate. On the other hand, the formation process of the crack line CL brings about a change from a crackless state obtained by forming the trench line TL to a state having cracks. This change is considered to be caused by the release of internal stress that the crackless state has.

According to the present embodiment, when the cutting edge 51 provided with the axially symmetrical tip 51N is slid on the upper surface SF1 of the glass substrate 4, the axial direction AX of the cutting edge 51 is relative to the upper surface SF1. It is assumed to be vertical (FIG. 2). Thereby, the relationship between the axial direction AX and the sliding direction DA becomes constant without depending on the direction DA in which the tip 51N of the blade edge 51 is slid. Therefore, it is not necessary to adjust the posture of the blade edge 51 according to the sliding direction DA of the blade edge 51.

In other embodiments described later, when the blade edge 51 is slid on the upper surface SF1 of the glass substrate 4 to form the trench line TL, the axial direction AX of the blade edge 51 is relative to the upper surface SF1. It is assumed to be vertical. Therefore, effects similar to those of the present embodiment can be obtained in other embodiments.

<Embodiment 2>
In the first embodiment, the trench line TL has a linear shape. On the other hand, in the present embodiment, the trench line TL includes a curved shape. Hereinafter, the process of forming the trench line TL will be described in detail.

Referring to FIG. 9, in the present embodiment, trench line TL has a curved shape. Correspondingly, the step of forming the trench line TL includes the step of sliding the tip 51N of the blade edge 51 in the direction DA1 (first direction), and then the tip 51N in the direction DA2 (second). Sliding in the direction).

Referring to FIG. 10, direction DA2 is different from direction DA1. Further, the sliding direction DA of the tip 51N of the blade edge 51 continuously changes between the direction DA1 and the direction DA2, as indicated by a broken line in the figure.

Subsequently, a crack line is formed along the trench line TL. Referring to FIG. 11, glass substrate 4 is divided along this crack line.

Since the configuration other than the above is substantially the same as the configuration of the first embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and description thereof is not repeated.

In the present embodiment, the sliding direction DA changes between the direction DA1 and the direction DA2. The tip 51N of the blade edge 51 has axial symmetry, and the axial direction AX of the blade edge 51 is perpendicular to the upper surface SF1 (FIG. 2). The relationship between the direction AX and the sliding direction DA is not affected. Therefore, it is not necessary to adjust the posture of the blade edge 51 according to the sliding direction DA of the blade edge 51. In other words, even when the trench line TL including the curved portion is formed, it is not necessary to adjust the posture of the blade edge 51 according to the sliding direction DA of the blade edge 51.

<Embodiment 3>
Referring to FIG. 12, in the present embodiment, trench line TL substantially includes a closed curve. Correspondingly, as shown in FIG. 13, the sliding direction DA changes in all directions as shown by the broken line in the figure. In other words, the tip 51N of the blade edge 51 is slid in all directions. Since the configuration other than the above is substantially the same as the configuration of the second embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and description thereof will not be repeated.

<Embodiment 4>
Referring to FIGS. 14 and 15, in the present embodiment, when trench line TL is formed, tip 51N is brought into contact with top surface SF1 of glass substrate 4 while tip 51N of blade edge 51 is in contact with top surface SF1. The heading direction DA is discontinuously changed from the direction DA1 to the direction DA2.

Subsequently, a crack line is formed along the trench line TL. Referring to FIG. 16, glass substrate 4 is divided along this crack line.

Since the configuration other than the above is substantially the same as the configuration of the second embodiment described above, the same or corresponding elements are denoted by the same reference numerals, and description thereof is not repeated.

At the moment when the direction DA changes discontinuously, the cutting edge 51 is almost stopped relative to the glass substrate 4. If the posture of the blade edge 51 is adjusted in such a stopped state, the tip 51N of the blade edge 51 or the glass substrate 4 is likely to be damaged. According to the present embodiment, it is not necessary to adjust the posture of the blade edge 51, and thus the above-described damage can be avoided.

<Embodiment 5>
Referring to FIG. 17, trench line TL formed in the present 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 trench line TL1 is formed, the direction DA toward the front end 51N is set as the direction DA1 while the front end 51N of the blade edge 51 is brought into contact with the upper surface SF1 of the glass substrate 4. When the trench line TL2 is formed, the direction DA toward the front end portion 51N is set as the direction DA2 while the front end portion 51N of the blade edge 51 is brought into contact with the upper surface SF1 of the glass substrate 4. The direction DA1 and the direction DA2 are opposite to each other. Accordingly, as shown in FIG. 18, the direction DA toward which the tip 51N is directed is either the direction DA1 or the direction DA2. In the formation of the trench line TL, the sliding direction DA is discontinuously changed between the direction DA1 and the direction DA2.

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 description thereof is not repeated.

If both the trench line TL1 and the trench line TL2 are formed by sliding in the direction DA1, the cutting edge 51 is moved from one edge (left edge in the figure) to the other edge (right edge in the figure). After the trench line TL1 is formed by being moved to, an operation only for returning the blade edge 51 toward the one edge is required. On the other hand, according to the present embodiment, the trench line TL2 is formed during this operation. This reduces the time required for the process. Therefore, productivity can be improved.

<Embodiment 6>
Referring to FIG. 19, in each of the embodiments described above, when the trench line TL is formed, the blade edge 51 may be rotated around the axial direction AX (see the rotation RT in the figure). The rotation RT may be performed while sliding the tip 51N of the blade edge 51 on the upper surface SF1 of the glass substrate 4. The rotation RT may be performed constantly during sliding or may be performed intermittently. Alternatively, the rotation RT may be performed without sliding the tip 51N of the blade edge 51 on the upper surface SF1 of the glass substrate 4. In this case, the cutting edge 51 is rotated with the cutting edge 51 stopped or with the cutting edge 51 separated from the glass substrate 4.

According to the present embodiment, local wear of the cutting edge 51 can be avoided. Therefore, the life of the blade edge 51 can be extended.

<Embodiment 7>
In each of the above-described embodiments, when the trench line TL is formed, the lubricant may be supplied to a position where the tip portion 51N of the blade edge 51 slides on the upper surface SF1 of the glass substrate 4. . In other words, in the process of forming the trench line TL (FIG. 4: step S30), as shown in FIG. 20, the cutting edge 51 is slid at the position where the lubricant is supplied and at the position where the lubricant is supplied. Step S32 may be included. As the lubricant, for example, a lubricating oil that is liquid at normal temperature or a solid lubricant that is normal at normal temperature can be used.

In each of the embodiments described above, the blade edge 51 that slides on the upper surface SF1 of the glass substrate 4 is likely to be worn when the trench line TL is formed. According to the present embodiment, such wear can be suppressed.

<Eighth embodiment>
Referring to FIG. 21, in step S10 (FIG. 4), glass substrate 4 similar to that in the first embodiment is prepared. However, in the present embodiment, an assist line AL is provided in advance on the upper surface SF1 of the glass substrate 4. Referring to FIG. 22, assist line AL has an assist trench line TLa and an assist crack line CLa. The assist trench line TLa has a groove shape. The assist crack line CLa is configured by a crack in the glass substrate 4 in the thickness direction DT extending along the assist trench line TLa.

In the present embodiment, the assist line AL is provided by the process of simultaneously forming the assist trench line TLa and the assist crack line CLa on the upper surface SF1 of the glass substrate 4. Such an assist line AL can be formed by a conventional typical scribing method. For example, such an assist line AL can be formed when the cutting edge rides on the edge ED of the upper surface SF1 of the glass substrate 4 and moves on the upper surface SF1, as indicated by an arrow in FIG. The cutting edge is preferably one that is rotatably held (wheel type). In other words, it is preferable that the cutting edge is not sliding but rotating on the glass substrate 4.

In addition, although the starting point of the assist line AL is the edge ED in FIG. 21, it may be separated from the edge ED. The assist line AL may be formed by a method similar to the method of forming the crack line CL in any of the first to seventh embodiments. Further, the assist line AL may be formed using a blade edge that is slid on the glass substrate 4. Alternatively, the assist line AL may be formed using the cutting edge 51 in order to facilitate the preparation of the cutting edge for the assist line AL described above.

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

Referring to FIG. 23, next, trench line TL is formed in step S30 (FIG. 4). In the present embodiment, the trench line TL is formed by sliding the blade edge 51 from the position N1 to the position N3a via the position N2 between the position N1 and the position N3a. The position N3a is disposed on the assist line AL. The position N2 is disposed between the position N1 and the position N3a. Preferably, the blade edge 51 is further slid to the position N4 beyond the position N3a on the assist line AL. The position N4 is preferably away from the edge ED.

The cutting edge 51 slid as described above to form the trench line TL intersects the assist line AL at the position N3a. This intersection causes a fine breakdown at the position N3a. Starting from this breakdown, a crack is generated so as to release the internal stress in the vicinity of the trench line TL. Specifically, a crack in the glass substrate 4 in the thickness direction extends from the position N3a located on the assist line AL along the trench line TL (see the arrow in FIG. 24). In other words, the formation of the crack line CL (FIG. 24) is started. Thereby, as step S50 (FIG. 4), the crack line CL is formed from the position N3a to the position N1.

The blade edge 51 is separated from the glass substrate 4 after reaching the position N3a. Preferably, the blade edge 51 is separated from the glass substrate 4 after sliding to the position N4 beyond the position N3a.

Next, in step S60 (FIG. 4), the glass substrate 4 is divided along the crack line CL as in the first embodiment. Thus, the method for dividing the glass substrate 4 of the present embodiment is performed.

In Embodiment 1, the blade edge 51 cuts down the glass substrate 4 at a position N3e (FIG. 5). On the other hand, according to the present embodiment, such cut-down is not necessary. Thereby, the damage to the blade edge | tip 51 or the glass substrate 4 which may arise in the case of cutting down with the blade edge | tip 51 can be avoided.

It should be noted that there is a case where the trigger for starting the formation of the crack line CL cannot be obtained only by the cutting edge 51 intersecting with the assist line AL. In such a case, the glass substrate 4 may be divided along the assist line AL after the trench line TL intersecting with the assist line AL is formed. Thereby, an opportunity to start the formation of the crack line CL can be obtained.

<Embodiment 9>
Referring to FIG. 26, first, glass substrate 4 is prepared as in the other embodiments (FIG. 4: step S10). Moreover, the blade edge | tip 51 is prepared (FIG. 4: step S20).

Next, as in the other embodiments, the tip 51N of the blade edge 51 is slid on the upper surface SF1 while the axial direction AX of the blade edge 51 is perpendicular to the upper surface SF1 of the glass substrate 4. This sliding is performed from the start point N1 to the end point N3 via the intermediate point N2. Thereby, 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 via the midpoint N2 is formed on the upper surface SF1 (FIG. 4: step S30).

The process of forming each of the trench lines TL includes a process of forming a low load section LR as a part of the trench line TL (FIG. 25: Step S30L) and a process 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 midpoint N2, and a high load section HR is formed from the midpoint N2 to the end point N3. The load applied to the cutting edge 51 in the process of forming the high load section HR is higher than the load used in the process of forming the low load section LR. Conversely, the load applied to the cutting edge 51 in the process of forming the low load section LR is lower than the load used in the process of forming the high load section HR, for example, 30 to 50 of the load in the high load section HR. %. Therefore, the width of the trench line in the high load section HR is larger than the width of the low load section LR. Moreover, as shown in FIG. 27, the depth of the high load section HR is larger than the depth of the low load section LR. The cross section of the trench line TL has, for example, a V shape with an angle of about 150 °.

In addition, since a high load is applied to the cutting edge 51 in the high load section HR, it is preferable that the distance of the high load section HR is small considering the life of the cutting edge 51. Furthermore, when the load is changed during the formation of the trench line TL, it is preferable that the scribe speed is reduced in the high load section HR in order to sufficiently increase the load in the high load section HR at a smaller distance. That is, since it is difficult to control to increase the load of the cutting edge 51 instantaneously, in practice, scribing is performed while increasing the load until a predetermined load is reached in a certain section starting from the position N2. . Therefore, by reducing the speed in the high load section HR, the load can be increased at a smaller distance, and the entire distance of the high load section HR can be reduced.

In the step of forming the trench line TL, a crackless state is obtained in which the glass substrate 4 is continuously connected in the direction DC (FIGS. 28 and 29) intersecting the trench line TL immediately below the trench line TL. To be done. For this purpose, the load applied to the blade edge is made large enough to cause plastic deformation of the glass substrate 4 and small enough not to generate cracks starting from this plastic deformation part.

Next, the process of forming a crack line (FIG. 4: step S50) is performed as follows.

30 to 32, first, an assist line AL that intersects the high load section HR is formed on the upper surface SF1 of the glass substrate 4. The assist line AL is accompanied by a crack that penetrates in the thickness direction of the glass substrate 4. The assist line AL can be formed by a normal scribing method.

Next, the glass substrate 4 is separated along the assist line AL. This separation can be performed by a normal break process. As a result of this separation, the crack of the glass substrate 4 in the thickness direction is extended along the trench line TL only in the high load section HR of the trench line TL.

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

Note that a crack line CL is hardly formed in a portion between the side newly generated by the separation and the end point N3. This is presumably because the distribution of internal stress generated in the vicinity of the trench line TL has anisotropy depending on the direction in which the trench line TL is formed.

Referring to FIG. 35, the glass substrate 4 is continuously disconnected in the direction DC intersecting the extending direction of the trench line TL immediately below the high load section HR of the trench line TL by the crack line CL. Here, “continuous connection” means a connection that is not interrupted by a crack. In addition, in the state where the continuous connection is cut as described above, the portions of the glass substrate 4 may be in contact with each other through the cracks of the crack line CL.

Next, a breaking process for dividing the glass substrate 4 along the trench line TL is performed (FIG. 4: Step S60). At this time, by applying a stress to the glass substrate 4, the crack is extended 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 (FIG. 26) in which the trench line TL is formed.

Thus, the glass substrate 4 is divided.

According to the present embodiment, when the trench line TL (FIGS. 26 and 27) for defining the position where the glass substrate 4 is divided is formed, the cutting edge in the low load section LR as compared with the high load section HR. The load applied to 51 (FIG. 1) is reduced. Thereby, damage to the blade edge 51 can be reduced.

Further, when the low load section LR of the low load section LR and the high load section HR is in a crackless state (FIGS. 33 and 34), there is no crack in the low load section LR as a starting point at which the glass substrate 4 is divided. . Therefore, when arbitrary processing is performed on the glass substrate 4 in this state, even if an unexpected stress is applied to the low load section LR, unintentional division of the glass substrate 4 is unlikely to occur. Therefore, the above process can be performed stably.

Further, when both the low load section LR and the high load section HR are in a crackless state (FIGS. 26 and 27), the trench line TL does not have a crack that is a starting point at which the glass substrate 4 is divided. Therefore, when arbitrary processing is performed on the glass substrate 4 in this state, even if an unexpected stress is applied to the trench line TL, unintentional division of the glass substrate 4 is unlikely to occur. Therefore, the above process can be performed more stably.

Further, the trench line TL is formed before the assist line AL is formed. Thereby, it is possible to avoid the influence of the assist line AL when the trench line TL is formed. In particular, the formation abnormality immediately after the cutting edge 51 passes over the assist line AL for forming the trench line TL can be avoided.

<Embodiment 10>
In the present embodiment, a case will be described in which the tip portion of the blade edge has the pseudo-axisymmetric property mentioned in the first embodiment.

FIG. 37 is a perspective view schematically showing the configuration of the cutting instrument 150 in the present embodiment. The cutting instrument 150 has a cutting edge 151 provided with a tip 151N instead of the cutting edge 51 (FIG. 2) provided with a tip 51N. The blade edge 151 has a polygonal pyramid shape having rounded vertices. The polygonal pyramid has a side surface SD and a ridge line RG. A tip 151N is provided at the apex of the polygonal pyramid.

38 is a schematic cross-sectional view perpendicular to the axial direction AX along the line XXXVIII-XXXVIII in FIG. Line XXXVIII-XXXVIII (FIG. 37) corresponds to a cross section perpendicular to the axial direction AX in the vicinity of the boundary between the tip portion 151N and the other portion of the blade edge 151. Hereinafter, the shape of the tip portion 151N in the cross-sectional view will be described.

The shape of the tip portion 151N is an n-side polygon (n ≧ 3) corresponding to the polygonal pyramid, preferably a regular polygon. In FIG. 38, a hexagon (n = 16) is illustrated. The tip portion 151N has n points PT corresponding to the n ridge lines RG (FIG. 37), and each of the points PT is in contact with the circumscribed circle CC. The tip portion 151N has n sides SD corresponding to n side surfaces SD (FIG. 37), and each of the sides SD has a dimension DS. As the size of the circumscribed circle CC is constant and n increases, the dimension DS decreases, and as a result, the cross-sectional shape of the tip portion 151N approaches a circle. Therefore, as n increases, the axial symmetry of the tip 151N in the axial direction AX approaches ideal geometric symmetry. Therefore, if n is large to some extent, it can be said that the tip portion 151N has axial symmetry in terms of its function. That is, it can be said that the tip portion 151N has the pseudo-axisymmetric property described above. According to the study of the present inventor, if the dimension DS is 1 μm or less, it can be said that the tip portion 151N has pseudo-axisymmetric property. For example, n satisfying this condition can be calculated from the angle of the tip portion 151N and the radius of curvature of the tip portion 151N near the axis AX. An example of this calculation will be described below.

FIG. 39 corresponds to a cross-sectional view along the line AA in FIG. 38, and shows the surface shapes of the tip portions 151Na to 151Nc having a radius of curvature R = 3 μm near the axis AX as an example of the tip portion 151N. Yes. Each of the tip portions 151Na to 151Nc has tip angles of 120 °, 130 °, and 140 °. Since the radius of curvature R in the vicinity of the axis AX is 3 μm, when the dimension along the axial direction AX of the tip 51N is 1 μm, each of the tips 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, n that makes the dimension DS (FIG. 38) 1 μm or less 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 a cross-sectional view along the line AA in FIG. 38, and shows the surface shapes of the tip portions 151Ni to 151Nk having a radius of curvature R = 5 μm near the axis AX as an example of the tip portion 151N. Yes. Each of the tip portions 151Ni to 151Nk has tip angles of 120 °, 130 °, and 140 °. Since the radius of curvature R in the vicinity of the axis AX is 5 μm, when the dimension along the axial direction AX of the tip 51N is 1 μm, each of the tips 151Ni to 151Nk has a diameter 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, n which sets the dimension DS (FIG. 38) to 1 μm or less 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.

Based on the examination results of FIG. 39 and FIG. 40, there may be a case where pseudo axial symmetry can be obtained if, for example, n ≧ 16. Therefore, n is preferably 16 or more. If n ≧ 25, pseudo axial symmetry can be obtained while using an arbitrary tip angle and radius of curvature within the range normally used. In view of workability and processing time for forming the tip, n is preferably not unnecessarily large, and therefore n is preferably 25 or less.

In order to obtain the blade edge 151, for example, the tip of a diamond piece may be given a substantially polygonal pyramid shape by polishing the tip of a piece of material having a polygonal column shape (for example, a diamond piece) a plurality of times. As a modification, R chamfering may be performed on the ridgeline RG (FIG. 37). As a result, the straight portion of the side SD (FIG. 38) is shortened, so that the shape of the tip portion 151N is closer to a circle. That is, the axial symmetry of the distal end portion 151N is closer to an ideal one. In this case, pseudo axial symmetry can be obtained even with smaller n.

In each of the above embodiments, the case where the edge of the upper surface SF1 is rectangular is illustrated, but other shapes may be used. Moreover, although the case where upper surface SF1 was flat was demonstrated, the upper surface may be curved. Further, although the case where the trench line TL is linear has been described, the trench line TL may be curved. Moreover, although the case where the glass substrate 4 was used as a brittle board | substrate was demonstrated, the brittle board | substrate may be made from brittle materials other than glass, for example, may be made from ceramics, silicon, a compound semiconductor, sapphire, or quartz.

AL assist line CL crack line AX axial direction SF1 upper surface (one surface)
HR High load section LR Low load section TL, TL1, TL2 Trench line 4 Glass substrate (brittle substrate)
50, 150

Cutting tool

51, 151

Cutting edge

51N, 151N, 151Na to 151Nc, 151Ni to 151Nk Tip 52 Support

Claims

a) preparing a brittle substrate having one surface and a thickness direction perpendicular to the one surface; and b) preparing a cutting edge provided with a tip having axial symmetry in the axial direction. And c) a groove shape by sliding the tip portion of the blade edge on the one surface while making the axial direction of the blade edge perpendicular to the one surface of the brittle substrate. Forming the trench line on the one surface of the brittle substrate by plastic deformation, the trench line continuously below the trench line in a direction in which the brittle substrate intersects the trench line. It is formed so as to obtain a crackless state that is connected, and d) extends the crack of the brittle substrate in the thickness direction along the trench line. A step of forming a crack line, wherein the brittle substrate is disconnected continuously in the direction intersecting the trench line below the trench line by the crack line; and e) the crack Cutting the brittle substrate along a line,
Method for cutting a brittle substrate.
Said step c)
c1) sliding the tip of the blade edge in the first direction;
c2) After the step c1), the step of sliding the tip of the cutting edge in a second direction different from the first direction;
The method for dividing a brittle substrate according to claim 1, comprising:
In the step c), the direction of the tip of the cutting edge is not changed from the first direction to the second direction while bringing the tip of the cutting edge into contact with the one surface of the brittle substrate. The method for dividing a brittle substrate according to claim 2, comprising a step of continuously changing.
The brittle substrate cutting method according to claim 1, wherein, in the step c), the tip of the cutting edge is slid in all directions.
The said blade edge | tip contains the right cone shape which has the axial symmetry in the said axial direction, The said front-end | tip part of the said blade edge | tip is provided in the vertex of the said right cone shape. Method for cutting a brittle substrate.
The brittle substrate cutting method according to any one of claims 1 to 5, wherein the step c) includes a step of rotating the blade edge around the axial direction.
The step of rotating the cutting edge around the axial direction includes a step of rotating the cutting edge around the axial direction while sliding the tip of the cutting edge on the one surface of the brittle substrate. 6. The method for dividing a brittle substrate according to 6.
The step of rotating the blade edge around the axial direction includes the step of rotating the blade edge around the axial direction without sliding the tip of the blade edge on the one surface of the brittle substrate. Item 8. The method for dividing a brittle substrate according to Item 6 or 7.
9. The method according to claim 1, wherein the step c) includes a step of supplying a lubricant to a position where the tip portion of the cutting edge slides on the one surface of the brittle substrate. A method for dividing a brittle substrate as described in 1.