JP2017149078A - Segmentation method for brittle substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an easy preparation of a blade tip and a sufficient lifetime of the tip when the tip having an apex where three faces joint is slid with the ridgeline on the back side.SOLUTION: A blade tip 51 is prepared which has a first face SD1, a second face SD2 adjacent to the first face SD1, and a third face SD3 that makes a ridgeline PS by adjacency to the second face SD2 and makes an apex PP by adjacency to each of the first face SD1 and the second face SD2. The ridgeline PS is processed by bevelling. A trench line TL having a groove shape is cracklessly formed on one face SF1 of the brittle substrate 4 by sliding the tip 51 on one face SF1 of the brittle substrate 4 from the ridgeline PS in a direction toward the first face SD1. A crack line CL is formed along the trench line TL. The brittle substrate 4 is segmented along the crack line CL.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for dividing a brittle substrate, and more particularly, to a method for dividing a brittle substrate using sliding of a blade edge.

  In the manufacture of electrical equipment such as flat display panels or solar cell panels, it is often necessary to break a 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 the 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 significantly different from the above-described typical cutting technique is 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.

  A technique that actively uses a trench line that does not involve cracks, such as the technique of Patent Document 2, is referred to as a “crackless scribing technique” in this specification. The trench line formed in the crackless scribing technique can be formed by sliding the blade edge at a lower load than a typical scribe line with simultaneous formation of cracks. If the load is small, the damage applied to the cutting edge is also small. Therefore, according to this cutting technique, the life of the cutting edge can be extended. As a kind of configuration of the cutting edge, according to the above-mentioned Patent Document 2, there is disclosed one having a vertex where three surfaces meet and a ridge line extending therefrom. Specifically, the cutting edge has a vertex at which the top surface, the first side surface, and the second side surface merge, and a ridge line formed by the first side surface and the second side surface. As directions in which the blade edge is slid on the brittle substrate, a first direction from the top surface to the ridge line and a second direction from the ridge line to the top surface are disclosed.

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

  The above-mentioned cutting edge is widely used not only in the crackless scribing technique but also in a typical scribing technique involving simultaneous generation of cracks. In a typical scribing technique, the sliding direction of the blade edge is standard in the first direction. In other words, it is standard that the ridge line is the front side and the top surface is the rear side. This is because it is easier to suppress damage to the cutting edge. On the other hand, in the crackless scribing technique, since the load on the cutting edge is low, damage to the cutting edge can be suppressed, so the second direction is also sufficiently practical. In the crackless scribing technique, the second direction may be particularly desired instead of the first direction depending on the application. The specific configuration of the cutting edge suitable for such a case has not yet been specifically studied because it has not been long since the study of crackless scribing technology began.

  The cutting edge used for industrial purposes is desired to be easily prepared because of its relatively high replacement frequency. In particular, when the second direction is selected as the sliding direction of the blade edge, damage to the blade edge is more likely to occur than when the first direction is selected. For this reason, the life of the cutting edge tends to be shortened, and the replacement frequency of the cutting edge tends to increase accordingly. Therefore, it is further desired that the cutting edge can be easily prepared.

  The present invention has been made to solve the above-described problems, and its purpose is to facilitate the cutting edge when the cutting edge having a vertex where three surfaces meet is slid with its ridge line as the rear side. And providing a method for dividing a brittle substrate, which can ensure a sufficient life of the cutting edge.

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) The first surface, the second surface adjacent to the first surface, and the second surface adjacent to each other to form a ridge line and adjacent to each of the first surface and the second surface. A cutting edge having a third surface forming a vertex is prepared. The ridge line is not chamfered.
c) By sliding the cutting edge on one surface of the brittle substrate in the direction from the ridge line toward the first surface, a trench line having a groove shape is formed on one surface of the brittle substrate by plastic deformation. 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) After step c), crack lines are formed by extending cracks in the brittle substrate in the thickness direction along the trench lines. 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.

The method for cutting a brittle substrate according to another 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) The first surface, the second surface adjacent to the first surface, and the second surface adjacent to each other to form a ridge line and adjacent to each of the first surface and the second surface. A cutting edge having a third surface forming a vertex is prepared. The cutting edge has a radius of curvature of 2 μm or less in a cross section perpendicular to the ridgeline.
c) By sliding the cutting edge on one surface of the brittle substrate in the direction from the ridge line toward the first surface, a trench line having a groove shape is formed on one surface of the brittle substrate by plastic deformation. 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) After step c), crack lines are formed by extending cracks in the brittle substrate in the thickness direction along the trench lines. 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.

  According to the brittle substrate cutting method according to one aspect of the present invention, the edge line of the cutting edge is not chamfered. Thereby, compared with the case where the ridgeline of a blade edge | tip has a chamfering process, a blade edge | tip can be prepared easily. Moreover, the load to a blade edge | tip can be made low by using a crackless scribing technique. Thereby, a sufficient life of the blade edge can be ensured while sliding with the ridge line as the rear side.

  According to the brittle substrate cutting method according to another aspect of the present invention, the cutting edge has a radius of curvature of 2 μm or less in a cross section perpendicular to the ridgeline. Such a radius of curvature can be easily obtained simply by refraining from chamfering the ridgeline after the pair of surfaces forming the ridgeline is formed. Therefore, the cutting edge can be easily prepared. Moreover, the load to a blade edge | tip can be made low by using a crackless scribing technique. Thereby, a sufficient life of the blade edge can be ensured while sliding with the ridge line as the rear side.

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 schematic plan view in the viewpoint of the arrow II of FIG. It is the elements on larger scale near the vertex of FIG. It is a graph which shows typically the surface profile for calculating the curvature radius in a cross section perpendicular | vertical to the ridgeline of FIG. It is a flowchart which shows schematically the structure of the cutting method of the brittle board | substrate in Embodiment 1-5 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. 7 is a schematic end view taken along line VII-VII in FIG. 6. 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. 9 is a schematic end view taken along line IX-IX in FIG. 8. It is a top view which shows roughly the structure of the cutting instrument used for the cutting method of the brittle board | substrate in the comparative example 1. FIG. It is a side view which shows the parting shape of the brittle board | substrate in the Example of Embodiment 1. FIG. It is a side view which shows the parting shape of the brittle board | substrate in the comparative example 3. It is a flowchart which shows schematically the structure of the formation method of a trench line in the cutting method of the brittle board | substrate in Embodiment 2 of this invention. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate in Embodiment 3 of this invention. FIG. 15 is a schematic end view taken along line XV-XV in FIG. 14. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 3 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 3 of this invention. 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 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 sectional drawing which shows schematically the structure of the blade edge | tip used for the cutting method of the brittle board | substrate in Embodiment 5 of this invention. It is sectional drawing which shows schematically the structure of the assist blade edge | tip used for the cutting method of the brittle board | substrate in Embodiment 5 of this invention.

  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>
(Configuration of the cutting tool)
With reference to FIG. 1 and FIG. 2, the structure of the cutting tool 50 used for the formation process of the trench line in the cutting method of the glass substrate 4 (brittle substrate) of this Embodiment is demonstrated first. The cutting instrument 50 has a cutting edge 51 and a shank 52. The blade edge 51 is held by being fixed to a shank 52 as its holder.

  The blade edge 51 is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. The plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1, the side surfaces SD2, and SD3 (first to third surfaces) face different directions and are adjacent to each other. The blade edge 51 has a vertex where the top surface SD1, the side surfaces SD2 and SD3 merge. A projection of the blade edge 51 is constituted by the vertex PP. Further, the side surfaces SD2 and SD3 form a ridge line PS constituting the side portion of the blade edge 51. The ridge line PS extends linearly from the apex PP and has a convex shape extending linearly. From the above configuration, the blade edge 51 forms a ridge line PS by being adjacent to the top surface SD1, the side surface SD2 adjacent to the top surface SD1, and the side surface SD2, and is apex by being adjacent to each of the top surface SD1 and the side surface SD2. And a side surface SD3 forming PP.

  The ridge line PS is not chamfered. For this reason, the ridgeline of the blade edge 51 has a sharp shape. Specifically, the blade edge 51 has a curvature radius of 2 μm or less as a curvature radius in a cross section perpendicular to the ridge line PS (hereinafter also simply referred to as “curvature radius of the ridge line PS”), preferably a curvature radius of 1 μm or less. Have An example of the method for measuring the radius of curvature will be described below.

  Referring to FIG. 3, the radius of curvature can be calculated from the measurement results of the surface profiles of side surfaces SD2 and SD3 on measurement line SR. The measurement line SR is located within the substantial working portion ER of the cutting edge 51 near the vertex PP to the glass substrate 4. The measurement line SR is orthogonal to the ridge line PS at a position away from the vertex PP. The action portion ER has a dimension L1 in a direction orthogonal to the ridge line PS and a dimension L2 in a direction along the ridge line PS. Typically, the dimension L1 is 30 μm or more and 50 μm or less, and the dimension L2 is 10 μm or more and 30 μm or less. The interval LD between the vertex PP and the measurement line SR is an interval such that the influence on the surface profile due to the presence of the vertex PP is sufficiently small, for example, about 5 μm. FIG. 4 is a surface profile schematically showing a measurement result of the relationship between the position on the measurement line SR and the height H. The surface profile can be measured using, for example, a laser microscope. By applying the circle RR to the obtained surface profile at the position of the ridgeline PS, the radius of curvature can be calculated.

  The cutting edge 51 is preferably a diamond point. That is, the cutting edge 51 is preferably made of diamond from the viewpoint that the hardness and the surface roughness can be reduced. More preferably, the cutting edge 51 is made of single crystal diamond. More preferably, crystallographically, the top surface SD1 is a {001} plane, and each of the side surfaces SD2 and SD3 is a {111} plane. In this case, although the side surfaces SD2 and SD3 have different orientations, they are crystal surfaces that are equivalent to each other in terms of crystallography.

  Diamond that is not a single crystal may be used. For example, polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may be used. Alternatively, sintered diamond obtained by bonding polycrystalline diamond particles, which are sintered from fine graphite or non-graphitic carbon without containing a binder such as an iron group element, with a binder such as an iron group element is used. May be.

  The shank 52 extends along the axial direction AX. The blade edge 51 is preferably attached to the shank 52 so that the normal direction of the top surface SD1 is approximately along the axial direction AX.

(Glass substrate cutting method)
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. 5), a glass substrate 4 (FIG. 1) 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. In the example shown in FIG. 6, 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. 5), the above-described cutting instrument 50 (FIGS. 1 and 2) having the cutting edge 51 is prepared.

  Referring to FIG. 6, trench line TL is formed in step S30 (FIG. 5). Specifically, the following steps are performed.

  First, the vertex PP of the blade edge 51 (FIG. 1) is pressed against the upper surface SF1 at the position N1. Thereby, the blade edge 51 contacts 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 other words, 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 when the cutting edge 51 starts to slide.

  Next, the blade edge 51 pressed as described above is slid on the upper surface SF1 of the glass substrate 4 (see the arrow in FIG. 6). The blade edge 51 (FIG. 1) is slid in the direction from the ridge line PS toward the top surface SD1 on the upper surface SF1. Strictly speaking, the blade edge 51 is slid in a direction DB in which the direction from the ridge line PS to the top surface SD1 via the vertex PP is projected onto the upper surface SF1. The direction DB is approximately along the direction in which the extending direction of the ridge line PS in the vicinity of the vertex PP is projected onto the upper surface SF1. In FIG. 1, the direction DB corresponds to a direction opposite to the direction in which the axial direction AX extending from the blade edge 51 is projected onto the upper surface SF1. Therefore, the blade edge 51 is pushed forward on the upper surface SF 1 by the shank 52.

  Each of the ridgeline PS and the top surface SD1 of the blade edge 51 (FIG. 1) slidable on the upper surface SF1 of the glass substrate 4 forms an angle AG1 and an angle AG2 with the upper surface SF1 of the glass substrate 4. The angle AG2 is preferably smaller than the angle AG1.

  The sliding causes plastic deformation on the upper surface SF1. As a result, a trench line TL (FIG. 7) having a groove shape is formed on the upper surface SF1. 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 by sliding the blade edge 51 from the position N1 to the position N3e via the position N2 between the position N1 and the position N3e. 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.

  The trench line TL is a crackless state in which the glass substrate 4 is continuously connected in the direction DC (FIG. 7) intersecting the extending direction (lateral direction in FIG. 6) 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 an appropriate crackless state, the load applied to the blade edge 51 is so small that cracks do not occur at the time of formation of the trench line TL, and internal stress that can generate cracks in a later process. It is adjusted so as to increase to such an extent that plastic deformation that produces the above state occurs.

  The cutting edge 51 slid as described above 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 ridge line PS (FIG. 1) of the blade edge 51 cuts down the edge ED of the upper surface SF1 of the glass substrate 4.

  With reference to FIG. 8 and FIG. 9, the above-mentioned cut-down causes a fine destruction at the 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. 8). In other words, the formation of the crack line CL is started. Thereby, as step S50 (FIG. 5), the crack line CL is formed from the position N3e to the position N1.

  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 cut | disconnected by the crack line CL in the direction DC (FIG. 9) which cross | intersects the extension direction (lateral direction in FIG. 8) of the trench line TL below the trench line TL. 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.

  The direction (arrow in FIG. 8) in which the crack line CL (FIG. 8) extends along the trench line TL (FIG. 6) is opposite to the direction in which the trench line TL is formed (arrow in FIG. 6). In order to generate the crack line CL in such a directional relationship, when the blade edge 51 slides in the direction DB (FIG. 1) for forming the trench line TL, the angle AG2 is made smaller than the angle AG1. Preferably it is. If this angular relationship is not satisfied, the crack line CL is unlikely to occur. Further, if the angle AG1 and the angle AG2 are approximately the same, it is likely that the crack line CL is generated or not.

  Next, in step S60 (FIG. 5), 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. 9) 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.

(Comparative Example 1)
Referring to FIG. 10, the vertex PP of the cutting edge 59 of this comparative example is provided at a location where the four surfaces SE1 to SE4 meet. Four ridge lines PS1 to PS4 are provided from the vertex PP. In this case, in the step of FIG. 6, the edge ED of the upper surface SF1 of the glass substrate 4 can be cut down at any one of the ridgelines PS1 to PS4. Therefore, like the present embodiment, there is an advantage that the crack line CL is easily formed. On the other hand, a high processing accuracy is required for forming the blade edge 59, and therefore, there is a disadvantage that the formation is not easy. This is because when the vertex PP of the blade edge is provided by the location where the surfaces SE1 to SE4 merge as in this comparative example, the position of the remaining one surface passes through the point where three of these surfaces merge. This is because it is necessary to match.

(Comparative Example 2)
In this comparative example, it is assumed that the sliding direction of the blade edge 51 is opposite to the direction DB (FIG. 1). In this case, in the process of FIG. 6, the top surface SD1 is cut off the edge ED of the upper surface SF1 of the glass substrate 4 instead of the ridgeline PS. That is, when cutting down, the sharp ridgeline PS acts in the present embodiment, whereas the flat top surface SD1 acts in the comparative example. For this reason, in this comparative example, it is difficult for fine breakage that triggers the start of formation of the crack line CL to occur. Therefore, it becomes difficult to reliably form the crack line CL.

(Example and Comparative Example 3)
FIG. 11 is a side view schematically showing a divided shape of the glass substrate 4 in an example of the present embodiment. FIG. 12 is a side view schematically showing a divided shape of the glass substrate 4 of Comparative Example 3. The thickness of the glass substrate 4 to be divided was set to 0.1 mm. The surface obtained by dividing the glass substrate 4 (hereinafter also referred to as “divided section”) corresponds to the right side in FIGS. 11 and 12, and is divided based on the surface profile obtained by the laser microscope. It is drawn with emphasis on the height difference of the cross section. The ridgeline PS (FIG. 3) of the cutting edge 51 used for the cutting was not chamfered in the example, and was chamfered in the comparative example 3. The radius of curvature of the ridge line PS was 0.6 μm in the example, and 3.9 μm in the comparative example 3.

  Compared with the divided section of Comparative Example 3, the divided section of the example had a good perpendicularity to the upper surface SF1. Further, the dividing surface of the example had better flatness than the dividing surface of Comparative Example 3. Specifically, the height difference in the sectional plane was 0.5 μm in the example and 2.3 μm in the comparative example 3. Here, the “altitude difference” is a difference between the lowest position and the highest position in the surface profile of the sectional surface. As described above, the reason why the embodiment has a better sectional surface than the comparative example 3 is that the internal stress applied to the glass substrate 4 when the trench line TL is formed due to the small radius of curvature of the ridge line PS. However, it is presumed that the concentration is given more locally.

(Summary of effects)
According to the present embodiment, the cutting edge 51 can be easily prepared. The first reason is that, unlike the first comparative example, the vertex of the blade edge 51 is provided as a location where the three surfaces of the top surface SD1, the side surface SD2, and the side surface SD3 merge. If the tip of the cutting edge is provided by a location where more than three surfaces meet, the remaining surface needs to be aligned so that it passes through the point where the three surfaces meet. For this reason, high processing accuracy is required. On the other hand, when the apex of the cutting edge is provided by the location where the three surfaces meet, such high machining accuracy is not necessary. The second reason is that the ridge line PS of the cutting edge 51 is not chamfered. Thereby, the cutting edge 51 can be easily prepared compared with the case where the ridge line PS of the cutting edge 51 is chamfered. From another viewpoint, the cutting edge 51 has a radius of curvature of 2 μm or less, preferably 1 μm or less, in a cross section perpendicular to the ridgeline PS. Such a radius of curvature can be easily obtained simply by refraining chamfering of the ridge line PS after the pair of surfaces forming the ridge line PS is formed. Therefore, the cutting edge 51 can be easily prepared.

  Furthermore, according to this Embodiment, the load to the blade edge | tip 51 can be made low by using a crackless scribing technique. Thereby, sufficient lifetime of the blade edge 51 can be ensured while sliding with the top surface SD1 as the front side and the ridgeline PS as the rear side.

  Furthermore, according to the present embodiment, a better sectional surface can be obtained as compared with Comparative Example 3 in which chamfering processing is performed on the ridge line PS. Specifically, a cross section having a good perpendicularity to the upper surface SF1 is obtained. Moreover, a cross section with good flatness can be obtained.

  Furthermore, according to the present embodiment, the crack line CL along the trench line TL can be more reliably formed. The first reason is that, unlike the comparative example 2, the ridgeline PS of the blade edge 51 slid to form the trench line TL cuts down the edge ED of the upper surface SF1 of the glass substrate 4. . The second reason is that the ridge line PS to be cut down in this way is in a sharp state because it is not chamfered or has a radius of curvature of 2 μm or less. The sharp ridgeline PS cuts down the edge ED of the upper surface SF1 of the glass substrate 4 so that the crack line CL can be more reliably formed.

<Embodiment 2>
Referring to FIG. 6 again, in the present embodiment, a lubricant is supplied to a position where blade edge 51 will slide on upper surface SF <b> 1 of glass substrate 4. In other words, as shown in FIG. 13, the step of forming the trench line TL (FIG. 6) (FIG. 5: step S30) includes the step S31 of supplying the lubricant and the cutting edge 51 at the position where the lubricant is supplied. Step S32 to be slid. In order to implement step S31, for example, a lubricant supply unit (not shown) may be provided in the shank 52 (FIG. 1). Since the configuration other than these is substantially the same as the configuration of the first embodiment described above, description thereof will not be repeated. Step S31 is also applicable to Embodiments 3 to 5 described later.

  In the present embodiment, the direction DB (FIG. 1) is selected as the traveling direction of the blade edge 51 as in the first embodiment. Under the condition that the load on the cutting edge 51 is the same, the sliding in the direction DB is more likely to damage the cutting edge 51 than the sliding in the opposite direction. According to the present embodiment, this damage can be effectively suppressed. Thereby, the lifetime of a blade edge can be extended.

<Embodiment 3>
Referring to FIG. 14, in step S10 (FIG. 5), glass substrate 4 similar to that in the first embodiment is prepared. However, in the present embodiment, an assist line AL is provided on the upper surface SF1 of the glass substrate 4. Referring to FIG. 15, 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 step 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 an ordinary typical scribing method. For example, such an assist line AL can be performed 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. Since a fine crack is generated by an impact at the time of riding, the assist crack line CLa can be easily formed at the same time when the assist trench line TLa is formed. In order to suppress damage to the cutting edge and the glass substrate 4 when riding, the cutting edge preferably has a shape different from the shape of the cutting edge 51 and suitable for riding. Specifically, it is preferable that the blade edge is one that is rotatably held (wheel-type one). 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. 14, it may be separated from the edge ED.

  Next, in step S20 (FIG. 5), a cutting edge 51 similar to that in the first embodiment is prepared. In addition, in order to facilitate the preparation of the cutting edge for the assist line AL described above, the assist line AL may be formed using the cutting edge 51. Alternatively, the assist line AL may be formed using a cutting edge having a shape similar to the shape of the cutting edge 51.

  Referring to FIG. 16, next, trench line TL is formed in step S30 (FIG. 5). Specifically, the following steps are performed.

  First, the same operation as in the first embodiment is performed. Specifically, the vertex PP of the blade edge 51 (FIG. 1) is pressed against the upper surface SF1 at the position N1. Next, the pressed blade edge 51 is slid in the direction DB (FIG. 1) on the upper surface SF1 of the glass substrate 4 (see the arrow in FIG. 16). As a result, the trench line TL is formed in a crackless state on the upper surface SF1.

  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. Therefore, the ridge line PS (FIG. 1) of the blade edge 51 also intersects the assist line AL. 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, the crack of the glass substrate 4 in the thickness direction DT extends from the position N3a located on the assist line AL along the trench line TL (see the arrow in FIG. 17). In other words, the crack line CL extends from the assist line AL intersected by the ridge line PS of the blade edge 51 along the trench line TL. Thereby, as step S50 (FIG. 5), the crack line CL is formed from the position N3a to the position N1. After the formation of the crack line CL, as in the first embodiment, the continuous connection is broken in the direction in which the glass substrate 4 intersects the trench line TL below the trench line TL by the crack line CL.

  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. 5), 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.

  According to the present embodiment, as in the first embodiment, the crack line CL along the trench line TL can be more reliably formed. This is because the ridge line PS of the cutting edge 51 slid to form the trench line TL is formed by the assist line AL provided on the upper surface SF1 of the glass substrate 4 and the apex of the sliding cutting edge 51. This is because stress is locally applied to the position N3a (FIG. 16) where the line TL intersects. By applying this stress, the start of formation of the crack line CL can be obtained with high certainty. In addition, substantially the same effects as those of the first embodiment can be obtained.

<Embodiment 4>
In the present embodiment, unlike the third embodiment, each of the assist trench line TLa and the assist crack line CLa included in the assist line AL (FIGS. 15 and 16) is the trench line TL described in the first embodiment. And a method similar to the method of forming the crack line CL. Hereinafter, this method will be specifically described.

  First, a cutting edge used for forming the assist line AL is prepared. This cutting edge may be the same as the cutting edge 51 (FIGS. 1 and 2). That is, the formation of the assist line AL and the formation of the trench line TL formed thereafter may be performed by the common cutting edge 51. Alternatively, a cutting edge different from the cutting edge 51 (hereinafter referred to as “assist cutting edge”) may be prepared as a cutting edge for forming the assist line AL. The assist blade edge may have the same shape as the shape of the blade edge 51 (FIGS. 1 and 2). Alternatively, the assist blade edge may have a shape different from the shape of the blade edge 51. Even when the assist blade edge has a shape different from the shape of the blade edge 51, the assist blade edge has the configuration of the top surface SD1, the side surface SD2, and the side surface SD3 that form the apex PP and the ridgeline PS, and has the shape described above. The differences are preferably due to differences in arrangement between these configurations. The “shape” of the cutting edge considered here is the shape of the portion in the vicinity of the vertex PP of the cutting edge, that is, the portion acting on the glass substrate 4, and the shape of the portion away from this portion is usually It does not matter. In the following, in order not to make the description redundant, the cutting edge used for forming the assist line AL may be simply referred to as “cutting edge” regardless of whether it is the cutting edge 51 or the assist cutting edge.

  Referring to FIG. 18, next, assist trench line TLa is formed in a crackless state by a method similar to the formation of trench line TL (FIG. 6). Referring to FIG. 19, next, an assist trench line TLa along the assist trench line TLa (FIG. 18) is formed by a method similar to the method of forming the crack line CL along the trench line TL (FIG. 8). The As a result, the assist line AL (FIG. 15) is formed.

  Next, as in the third embodiment, trench lines TL (FIG. 16) and crack lines CL (FIG. 17) are formed in steps S30 and S50 (FIG. 5), and in step S60 (FIG. 5), The glass substrate 4 is divided along the crack line CL. Thus, the method for dividing the glass substrate 4 of the present embodiment is performed.

  In the present embodiment, the load applied to the blade edge 51 in forming the trench line TL (FIG. 16) is made larger than the load applied to the blade edge in forming the assist trench line TLa (FIG. 18). . According to the inventor's experimental examination, the crack line CL (FIG. 17) can be generated more reliably by providing a difference in the load as described above.

  Preferably, the angle AG2 (FIG. 1) in forming the trench line TL (FIG. 16) is smaller than the angle AG2 (FIG. 1) in forming the assist trench line TLa. By using such an angular relationship, in particular, even when the cutting edge for forming the assist trench line TLa is the cutting edge 51 or an assisting cutting edge having the same shape as the cutting edge 51, It is easy to provide a difference in load. This is because, when the shape of the cutting edge is the same, the smaller the angle AG2, the larger the load that can form the trench line TL (or the assist trench line TLa) in a crackless state. In the formation of the trench line TL, if the angle AG2 is too large, it is difficult to achieve both the formation of the trench line TL in a crackless state and the use of a load larger than the load at the time of forming the assist trench line TLa. It becomes. On the other hand, when the angle AG2 (FIG. 1) in forming the trench line TL (FIG. 16) is smaller than the angle AG2 (FIG. 1) in forming the assist trench line TLa, in forming the trench line TL, It becomes easy to use a load larger than the load at the time of forming the assist trench line TLa. Therefore, it is unnecessary to consider that a high-load cutting edge design is applied to the cutting edge 51 for the trench line TL and a low-load cutting edge design is applied to the cutting edge for the assist trench line TLa. Therefore, in the formation of the assist trench line TLa, the cutting edge 51 used for forming the trench line TL or the assist cutting edge having the same shape as the shape can be used.

  As described above, when a difference is provided in the angle AG2 (FIG. 1), the assist blade edge is prepared separately from the blade edge 51 for forming the trench line TL as the blade edge for forming the assist trench line TLa. Is preferred. Accordingly, the posture of the blade edge 51 can be fixed in a state where the angle AG2 of the blade edge 51 is suitable for forming the trench line TL. In other words, it is not necessary to adjust the posture of the blade edge 51 for optimizing the angle AG2 between the step of forming the assist trench line TLa and the step of forming the trench line TL.

<Embodiment 5>
Referring to FIGS. 20 and 21, in the present embodiment, blade edge 51 is used in forming trench line TL, and the assist blade edge described in the fourth embodiment is used in forming assist trench line TLa. The assist blade edge 51a is used. The shape of the blade edge 51 and the shape of the assist blade edge 51a are different from each other. For example, each of the blade edge 51 and the assist blade edge 51a in the vicinity of the vertex PP (see FIG. 2) has the angles AP and APa of the ridge line PS in a cross section perpendicular to the ridge line PS, and the angle AP is larger than the angle APa. Since the configuration other than these is substantially the same as the configuration of the fourth embodiment described above, description thereof will not be repeated.

  According to the present embodiment, blade edges having different shapes are used when the assist trench line TLa is formed and when the trench line TL is formed. Thereby, as the shape of the cutting edge, in the formation of each of the assist trench line TLa and the trench line TL, a shape suitable for a relatively low load and a shape suitable for a high load can be used. Therefore, a crackless state can be more reliably obtained when the assist trench line TLa and the trench line TL are formed, and the assist crack line CLa and the crack line CL are more reliably formed from the assist trench line TLa and the trench line TL, respectively. Can be generated.

  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.

ED edge AL assist line CL crack line SD1 Top (first side)
SD2 side (second side)
SD3 side (third side)
SF, SF1 Upper surface (one surface)
PP vertex TL trench line PS ridge line CLa assist crack line TLa assist trench line 4 Glass substrate (brittle substrate)
51 Cutting edge 51a Assist cutting edge

Claims (4)

a) providing a brittle substrate having one surface and a thickness direction perpendicular to the one surface; and b) a first surface and a second surface adjacent to the first surface. And a third surface that forms a ridge line adjacent to the second surface and forms a vertex by adjacent to each of the first surface and the second surface. The crest line is not chamfered, and c) a groove by sliding the cutting edge on the one surface of the brittle substrate in a direction from the ridge line toward the first surface. Forming a trench line having a shape on the one surface of the brittle substrate by plastic deformation, the trench line being continuous in a direction in which the brittle substrate intersects the trench line below the trench line. In a state connected to D) a step of forming a crack line by extending cracks of the brittle substrate in the thickness direction along the trench line after the step c). The brittle substrate is disconnected continuously in the direction intersecting the trench line below the trench line by the crack line, and further, e) the brittle substrate is divided along the crack line. Comprising the steps,
Method for cutting a brittle substrate. a) providing a brittle substrate having one surface and a thickness direction perpendicular to the one surface; and b) a first surface and a second surface adjacent to the first surface. And a third surface that forms a ridge line adjacent to the second surface and forms a vertex by adjacent to each of the first surface and the second surface. The cutting edge has a radius of curvature of 2 μm or less in a cross section perpendicular to the ridgeline, and c) a direction from the ridgeline toward the first surface on the one surface of the brittle substrate Forming a trench line having a groove shape on the one surface of the brittle substrate by plastic deformation, the trench line including a step of forming the trench line below the trench line. In the direction intersecting the line Formed so as to obtain a crackless state that is continuously connected; and d) after the step c), the crack of the brittle substrate in the thickness direction is extended 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) Cutting the brittle substrate along
Method for cutting a brittle substrate. Said step d)
The ridgeline of the cutting edge slid by the step c) cuts down the edge of the one surface of the brittle substrate;
Extending the crack line along the trench line from the edge cut down by the ridge line of the cutting edge;
The method for dividing a brittle substrate according to claim 1, comprising: The step a) includes an assist trench line having a groove shape on the one surface of the brittle substrate, and a crack of the brittle substrate in the thickness direction extending along the assist trench line. Including a step of forming an assist line having an assist crack line,
Said step d)
The ridgeline of the cutting edge slid by the step c) intersects the assist line provided on the one surface of the brittle substrate;
Extending the crack line along the trench line from the assist line intersected by the ridge line of the cutting edge;
The method for dividing a brittle substrate according to claim 1, comprising:

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