Method for processing brittle material substrate and method for dividing brittle material substrate

Abstract

The present invention provides a processing method capable of suppressing the generation of burrs when cutting out a shaped product surrounded by a scribe line of a closed curve from a brittle material substrate such as a glass substrate. The processing is performed by a scribing process in which the inner side position of the substrate is pressed as a starting point to fix the scribing tool of a fixed blade, and the scribing line is processed by moving around in a manner to draw a closed curve with a groove line, and further, a turning-off portion K having a radius of curvature of 0.5 mm or less is drawn at a joint position in succession to the scribing line, and a separation scribe line reaching the end edge of the substrate is processed, so that a crack traveling in the thickness direction is induced in the groove of the groove line.

Description

TECHNICAL FIELD

[0001] The present application relates to a processing method and a separation method of a brittle material substrate such as a glass substrate used for a display panel such as a liquid crystal display (LCD) for a mobile terminal, an organic EL display (OLED), and a solar cell panel. The present application particularly relates to a separation method of processing a groove for separation formed as a closed curve on a brittle material substrate to cut out a shaped product surrounded by the closed curve. In the present specification, "shaped" means a shape including a curve in addition to a straight line, and a product cut out in a shape surrounded by a closed curve including a curved portion in addition to a straight line is referred to as a shaped product. BACKGROUND

[0002] In the separation method of the glass substrate and the like, a linear groove is formed on the substrate surface by scribing on the substrate surface with a cutter wheel as a rotary cutter or a blade of a scribing tool using a fixed cutter having a pointed tip. The groove is a cutout in which plastic deformation occurs on the substrate surface, and the linear groove is referred to as a scribe line.

[0003] In the present specification, a tool that scribes a groove in which plastic deformation occurs on a substrate using a fixed cutter such as a diamond cutter having a pointed tip, without using a rotary cutter, is referred to as a scribing tool.

[0004] A region surrounded by a closed curve formed of a quadrangle in which the corner portions of four corners as shown in Figure 4 The scribe line SL1 of the closed curve is processed as follows: using a cutter wheel (rotary cutter) or a scribing tool (fixed cutter), scribing is started from the position of the starting point P on the surface of the brittle material substrate W, and is performed so as to encircle (one turn) in a manner of tracing the above-described quadrangle, and is connected again to the position of the starting point P. Then, continuously with the scribe line SL1 of the closed curve, a scribe line SL2 that passes through the starting point P and extends up to the end N of the substrate is formed in one stroke.

[0005] As shown in (b) of Figure 6 While the scribe line is scribed, the scribe line can be accompanied by a crack C extending downward from the scribe line SL. Here, the scribe line accompanied by the crack C is referred to as a crack line CL.

[0006] If the crack line CL accompanied by the crack C is formed, the crack C of the crack line CL can be made to propagate in the thickness direction by imparting a mechanical stress by bending the substrate or the like in a subsequent breaking process, or by imparting a thermal stress by local heating or the like, and the substrate can be completely separated, and a shaped product A surrounded by the closed curve can be cut out.

[0007] To form such a crack line CL, a trigger (starting crack) is needed as its starting point. This trigger can be easily formed by pressing the cutting edge of a scribing tool or rotary cutter (from the outside of the substrate) against the edge of the substrate. This is because localized damage occurs at the edge of the substrate due to impact from the pressing of the cutting edge. Furthermore, by moving the pressed cutting edge on the surface of the substrate, the crack line CL can extend from the trigger in the direction of the cutting edge's movement. Additionally, a scribing method that includes the edge of the substrate within the scribing area, similar to the case where the cutting wheel is rotated to scribing from the edge of the substrate, is called "outer cutting." On the other hand, a scribing method that uses a position moving away from the edge of the substrate towards the inside of the substrate as the starting point is called "inner cutting."

[0008] As a method for forming a trigger, there are also methods that do not rely on the blade pressing against the edge of the substrate. For example, a vibration generating member is attached to the scribing head that holds the scribing tool or blade wheel, and the blade is pressed to the scribing starting point (the starting point of the "inner cut") that moves away from the edge of the substrate toward the inside of the substrate, so that the blade vibrates to apply an impact to the substrate, thereby forming a trigger (see Patent Document 1).

[0009] However, in any of the existing methods mentioned above, if the impact between the cutting edge and the substrate exceeds the required strength when the processing is triggered, it will lead to problems such as damage to the cutting edge, notches at the edge of the substrate, and substrate breakage. Therefore, the cutting conditions such as the cutting edge movement speed and the cutting edge load during the marking process are greatly limited.

[0010] Therefore, the applicant previously proposed the following processing method in Patent Document 2.

[0011] That is, initially, a fixed-blade scribing tool or scribing wheel is used to scribble from near one edge to near the other edge of the substrate surface without including the edge, forming a shallow groove-shaped scribing line SL without cracks C (refer to...). Figure 6 (a)). Therefore, scribing can be performed without applying a strong impact at the scribing initiation point, reliably producing groove-shaped scribing lines SL without cracks C. Below, a shallow groove-shaped scribing line SL without cracks C (refer to...) will be described. Figure 6 (a) is called "groove line TL".

[0012] Next, near one end of the groove line TL, an "auxiliary line" is formed by scribing with a cutting edge in a direction orthogonal to the groove line TL as shown in Patent Document 2. At this time, near the intersection of the auxiliary line and the groove line TL, on the side of the groove line TL, crack C travels in the thickness direction, inducing crack C (see reference). Figure 6(b)). Then, it is possible to trigger the crack C from the intersection point and extend it along the groove line TL, thus forming the crack line CL.

[0013] According to the above processing method, since it is not necessary to form a scribe line with crack C (i.e., crack line CL) when processing the initial scribing line, the range (degrees of freedom) of selectable scribing conditions for scribing load (blade load) expands towards the low load side. That is, as long as a groove line TL without crack C is formed, scribing can be performed relatively easily with a small scribing load. As a result, the substrate is not prone to breakage due to excessive scribing load. In particular, the thinner the substrate, the more significant the effect of preventing breakage, which is very effective when processing glass substrates with a thickness of less than 200 μm. Moreover, scribing with a groove line TL can achieve high-quality processing with less damage, thus improving the processing quality throughout the entire circumference. In addition, due to the use of a low load, blade wear or damage can also be suppressed.

[0014] Existing technical documents

[0015] Patent documents

[0016] Patent Document 1: Japanese Patent Application Publication No. 2000-264656;

[0017] Patent document 2: Japanese Patent No. 6249091.

[0018] The problem the invention aims to solve

[0019] Therefore, when cutting out from a brittle material substrate, such as Figure 4 In the case of an irregularly shaped article A enclosed by such a closed curve, it is preferable to induce cracks and transform the initially drawn scribing line into a crack line after forming the groove line. That is, after machining the scribing line SL1 of the closed curve into a groove line TL without cracks, the groove line TL is transformed into a crack line CL with cracks C.

[0020] Specifically, using a cutting wheel or scribing tool, scribing begins from the starting point P in an "inner cut" manner, encircling the area in a quadrilateral pattern and reconnecting at the starting point P again, thus creating a closed-curve scribing line SL1. This encircling scribing line is scribed as a groove line without cracks. When the encircling movement reconnects at the starting point P again (similar to when the auxiliary line is formed), the groove line near the starting point P can be transformed into a crack line CL with cracks C by the impact or stress change at this time. Then, continuously with the scribing line SL1, a separation scribing line SL2 is formed in one stroke, passing through the starting point P (hereinafter, the position of the starting point P after the encircling movement will also be referred to as the contact point P) and extending straight to the substrate end N.

[0021] However, experiments show that if the above method is used for engraving, when cutting out the irregularly shaped product A by applying stress during the fracture process, as... Figure 5 As shown in the enlarged view of (b), a stepped burr B (also called a horn-like object B) is formed near the contact point P. The cause of burr B can be attributed to the following: when machining the straight separation scribe line SL2 starting from the contact point P, the machining passes near the already machined closed curve scribe line SL1. This area retains the stress generated by the first scribe line, and at the point where it branches off from the contact point P, the line is repeatedly formed, or small cracks are generated. Such burrs B are a major cause of significant deterioration in the processing quality of the product and the production of defective products. Summary of the Invention

[0022] Therefore, the present invention solves the problems of processing scribing lines along closed curves and generating burrs during subsequent fracture. Its purpose is to provide a processing method for brittle material substrates that can suppress the generation of burrs when cutting irregularly shaped products from brittle material substrates and cut out good products with a high yield.

[0023] Solution for solving the problem

[0024] The present invention, which addresses the aforementioned problems, provides a method for processing a brittle material substrate, comprising: a scribing process in which a scribing tool with a fixed blade is pressed against a position on the surface of the brittle material substrate, a position away from the edge of the substrate from the inward side, is used as the scribing starting point. This tool is moved around the substrate in a manner that draws a closed curve with groove lines without cracks, and then returns to the scribing starting point to process scribing lines. After the scribing lines are continuously drawn at the scribing starting point, i.e., the contact point position, after the circular movement, a turning portion K with a radius of curvature of less than 0.5 mm is drawn to turn the tool, a separation scribing line is processed, thereby inducing cracks that travel in the thickness direction in the grooves of the groove lines.

[0025] Invention Effects

[0026] According to the present invention, since the scribing lines are formed as groove lines without cracks, scribing conditions with lower loads can be selected compared to the case where scribing lines are processed with cracks, and problems such as cracking caused by overload processing can be eliminated.

[0027] Further, by using a scribing tool capable of making a turn with a small radius of curvature, making a turn at a position of the junction (start point) of the scribing line and the groove line, and making a separation scribing line by making a turn of a circular arc shape with a small radius of curvature of 0.5 mm or less at the position of the junction (start point), the separation scribing line can be made to depart from the scribing line of the closed curve immediately. Therefore, in the vicinity of the intersection of the separation scribing line and the scribing line of the closed curve, the influence of the respective residual stresses is not easily exerted, and the generation of burrs in the scribing line of the closed curve can be suppressed, and even if burrs are generated, the burrs can be suppressed to a size that is tolerable.

[0028] In the above-described application, the closed curve can include a straight line portion and a curved line portion, and the position of the junction can be included in the straight line portion.

[0029] Since the separation scribing line is made to reach the end edge of the substrate after making a turn at the position of the junction (start point) by making a turn of a radius of curvature of 0.5 mm or less, the separation scribing line can be made to depart from the scribing line of the closed curve immediately even if the position of the junction (start point) is provided in the straight line portion. If the position of the junction (start point) is provided in the straight line portion as such, the radius of curvature of the turn of the separation scribing line can be set regardless of the shape of the corner portion (curved line portion) of the cut-out shaped product, irrespective of the shape of the corner.

[0030] Here, the separation scribing line can be made to be linear after making a turn at the turn portion K, and the angle formed by the straight line portion of the closed curve including the position of the junction and the straight line of the separation scribing line can be 20° to 90°.

[0031] In order to make the separation scribing line into a linear shape that is easy to break, the separation scribing line is made not to overlap the straight line portion of the closed curve, and thus needs to be made not to be parallel to the straight line portion of the closed curve. According to the verification experiment described later, it is found that the above-described angle is set to 20° to 90°.

[0032] In the above-described application, the brittle material substrate can be a glass substrate with a plate thickness of 200 μm or less.

[0033] According to the present application, even a glass substrate with a plate thickness of 200 μm or less, which is technically difficult to separate and process, can be subjected to separation processing in which the generation of burrs is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 FIG. 1 is a view for explaining a scribing process of a first embodiment of the method of the present application, Figure 1 (a) of FIG. 1 shows the entire substrate, Figure 1(b) is a diagram showing a portion of the image magnified.

[0035] Figure 2 This is an explanatory diagram illustrating the scribing process of a second embodiment of the method of the present invention.

[0036] Figure 3 A diagram illustrating an example of a scribing tool used in this invention.

[0037] Figure 4 This is an explanatory diagram illustrating an experimental segmentation method performed by the inventors for verification purposes.

[0038] Figure 5 For the purpose of illustration Figure 4 An enlarged view of the segmentation result obtained by the segmentation method.

[0039] Figure 6 (a) is a cross-sectional view showing the scribed lines (grooves) formed on the substrate without crack C. Figure 6 (b) is a cross-sectional view showing the criterion line (crack line CL) containing crack C. Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Examples of substrates that can be processed according to the present invention include glass substrates, ceramic substrates, silicon substrates, compound semiconductor substrates, sapphire substrates, and quartz substrates. Among these, the substrates effective for the present invention are thin substrates that require reduced scribing load during processing, particularly thin glass substrates of 200 μm or less.

[0041] In this embodiment, using Figure 3 The engraving tool 1 shown. The engraving tool 1 has a cutting edge 1b made of a frustum-shaped component supported by a retainer 1a. The top surface 1c at the top of the cutting edge 1b and the corner where the cutting edge 1d around the cutting edge 1b connects to form a cutting edge 1e (fixed blade).

[0042] Alternatively, the cutting edge 1b can be formed as a triangular frustum or a pentagonal frustum, or a polygonal frustum, instead of a square pyramidal frustum. Furthermore, the cutting edge 1e can also be formed at the corner of a prism or polygonal plate-shaped cutting edge 1b, creating a top surface and an edge line.

[0043] Next, the segmentation method of this embodiment will be explained.

[0044] <Implementation Method 1>

[0045] As the first stage of substrate division, the following scribing process is performed. For example... Figure 1As shown, as a scribing process, a scribe line SL1 that is a closed curve of a quadrangle in which the corners of the four corners of the quadrangle are rounded is processed using the scribing tool 1 on the surface of a glass substrate W (hereinafter referred to as a substrate). Specifically, the scribe line SL1 is started to be scribed from a shallow groove-like groove line (a) that does not have a crack, with the middle position of one side (a straight line portion) in the closed curve of the above-described quadrangle as a starting point Pl, and the blade le of the scribing tool 1 pressed. Then, the scribing tool 1 is moved around in such a manner that the above-described quadrangle is described until the groove line is processed with the scribe line SL1 again connected at the position of the starting point Pl (hereinafter, the position of the starting point Pl after the movement around will also be referred to as a connection point Pl). Figure 6

[0046] In the above-described scribing process, a small curvature radius R of an arc-like turning portion K of 0.5 mm or less is described from the position of the connection point Pl as a starting point, after the scribe line SL1 of the closed curve is completed continuously at the connection point Pl, the scribing direction is turned, and further, a separation scribe line SL2 that reaches the end edge of the substrate is processed in one stroke continuously thereto. Here, by using the scribing tool 1 of a fixed blade with a pointed tip, the curvature radius R of the turning portion K can be sufficiently reduced to turn compared to the case of using a rotary blade. Specifically, by making the curvature radius R 1 mm to 0.1 mm, and making the blade pointed, it is also possible to turn with a curvature radius R of less than 0.1 mm.

[0047] The separation scribe line SL2 after the turning at the turning portion K reaches the end edge of the substrate W. The groove line that is connected to the end edge of the substrate W like this becomes a crack line CL (b) that has a crack C by inducing a crack that runs in the thickness direction in the groove of the groove line near the end edge of the substrate W. Figure 6 In order to be easily broken in the following breaking process, it is preferable that the separation scribe line SL2 of this portion be described in a straight line. However, as long as it is to the extent that does not hinder the breaking, a curved line can also be adopted.

[0048] In addition, depending on the environmental conditions, the scribing conditions, the crack C can be formed only near the end edge of the substrate W and be short, or can be formed along the separation scribe line SL2 and the scribe line SL1 of the closed curve and be long, and in either case, it is possible to reliably extend the entire groove line by imparting stress thereafter, so as long as it is possible to induce a crack at least near the end edge.

[0049] Furthermore, from the viewpoint of suppressing burrs, it is particularly preferable that, when the above-described separation scribe line SL2 is described in a straight line, the angle a formed by the straight line portion of the scribe line SL1 that includes the connection point Pl (the straight line portion at which the connection point Pl and the turning portion K are connected) and the straight line of the separation scribe line SL2 be in the range of 20° to 90° in a manner that sandwiches the turning portion K.​

[0050] Then, after forming the crack line CL with a crack accompanying the end edge portion of the substrate W separated by the scribe line SL2, a breaking process of mechanically bending the substrate or applying stress to the substrate by heating through light irradiation, warm heat, cold heat jetting, etc. is performed to cut out from the scribe line SL2, and further to cut out the shaped product A surrounded by the closed curve along the scribe line SLl.

[0051] According to the above method, since the scribe line SLl is processed into a groove line without a crack, a lower scribe load can be selected from the beginning compared to the case of processing the scribe line with a crack. Further, since the turning portion is provided which turns with a small radius of curvature R of 0.5 mm or less from the junction PI, the separation scribe line SL2 can depart from the closed curve at a position next to the junction, and is not easily affected by the separation scribe line, the area of residual stress near the separation scribe line at the time of separation along the scribe line of the closed curve. As a result, the generation of burrs can be suppressed.

[0052] (Verification Experiment 1)

[0053] Verification purpose: The starting point (junction) PI of the scribe line SLl of the closed curve is set to the vicinity of the center of the straight line portion of the closed curve, and the radius of curvature R of the turning portion K which turns from the straight line portion of the scribe line SLl of the closed curve is set as a variable parameter, to verify the size of the burr generated when the straight line-shaped separation scribe line SL2 extending to the end edge is processed (refer to Figure 1 ).

[0054] Substrate plate thickness: 50 μm;

[0055] Pressing force of scribe tool: 1.3 N;

[0056] Scribe speed: 10 mm / sec (0.1 mm / sec for turning portion);

[0057] Angle α: fixed at 90°;

[0058] Radius of curvature of turning portion K: 10 mm, 1 mm, 0.5 to 0.1 mm.

[0059] The verification results are shown in Table 1. As the judgment of the merits and demerits of the shaped product, the size of the burr is 15 μm or more is set to "poor", 15 to 5 μm is set to "good", and less than 5 μm is set to "best".

[0060] [Table 1]

[0061]

[0062] As seen from Table 1, there is a tendency that the smaller the curvature radius R is, the smaller the burr size is. In particular, when the curvature radius is set to 0.4 mm or less, the effect of suppressing burrs is remarkable.

[0063] <Embodiment 2>

[0064] The scribing process was performed using the same scribing tool 1 as in Embodiment 1, the starting point (joint) Pl of the scribe line SLl of the closed curve was set to the end of the straight line portion of the scribe line SLl of the closed curve, i.e., the boundary position with the curved portion (curve portion of the corner), and the scribe line SNl of the closed curve adjoining the position of the joint Pl was processed by moving around. Then, continuously with the scribe line SNl, after turning at the turning portion with the curvature radius R from the position of the joint Pl, the scribe line SL2 for separation extending in a straight line to the substrate end Nl was formed in one stroke at an angle a of preferably 20° to 90°.

[0065] In this embodiment, as in the previous Embodiment 1, the generation of burrs can also be suppressed.

[0066] (Verification Experiment 2)

[0067] Verification purpose: The starting point (joint) Pl of the scribe line SLl of the closed curve was set to the end of the straight line portion of the scribe line SLl of the closed curve (boundary position with the curve portion of the corner), and the angle a formed by the straight line portion of the scribe line SL2 for separation and the straight line portion of the scribe line SLl of the closed curve was used as a variable parameter to verify the relationship with the size of the burrs generated (see Figure 2 ).

[0068] Substrate thickness: 50 μm;

[0069] Pressing force of scribing tool: 1.3 N;

[0070] Scribing speed: 10 mm / sec (0.1 mm / sec for the turning portion);

[0071] Curvature radius of the turning portion K: fixed at 0.1 mm;

[0072] Angle a: 0°, 20°, 45°, 70°, 90°.

[0073] The verification results are shown in Table 2. As the judgment of the merits and demerits of the shaped product, the size of the burr of 15 μm or more was set to "poor", 15 to 5 μm was set to "good", and less than 5 μm was set to "best".

[0074] [Table 2]

[0075]

[0076] As seen from Table 2, burrs were 2 μm in all cases of 20° to 90° except for the case of 0° (corresponding to the prior art example) of angle α, and the effect of suppressing burrs was remarkable. Figure 4

[0077] In addition, although not shown, in the case where the position of the starting point (junction) is in the center of the straight portion as in Verification Experiment 1, it was determined to be "good" or more in the range of 20° to 90° of angle α, and the effect of suppressing burrs could be obtained.

[0078] The above describes representative embodiments of the present application, but the present application is not necessarily limited to the above-described embodiments. For example, although a substrate having a thickness of 50 μm was used in the above-described embodiments, the present application can also be applied to the case where the plate thickness of the substrate is greater than 100 μm. Further, in the turning portion, the pressing force of the scribing tool can also be reduced.

[0079] Further, in the above-described embodiments, a crack line for inducing a crack was formed in the groove of the scribe line SL2 so as to reach the end edge of the substrate W, but an auxiliary line can also be formed as the crack line for inducing a crack in a manner intersecting the scribe line SL2. In this case, the scribe line SL2 can be formed at a position apart from the end edge of the substrate W. Then, by intersecting the scribe line SL2 with the auxiliary line, a crack of the auxiliary line is induced from the intersection with the scribe line SL2, and the scribe line SL2 becomes a crack line CL with the crack C.

[0080] Further, the present application can be appropriately modified and changed without departing from the scope of the patent claim in order to achieve the object.

[0081] Industrial Applicability

[0082] The present application can be used when cutting out a shaped product from a brittle material substrate such as a glass substrate.

[0083] Explanation of Reference Numerals

[0084] A: Shaped product to be divided;

[0085] C: Crack;

[0086] CL: Crack line;

[0087] K: Corner of the turning portion;

[0088] N1: End of the substrate;

[0089] P1: Scribing starting point (junction);

[0090] SL: Scribe line; ​

[0091] SL1: scribe line of a closed curve;

[0092] SL2: scribe line for separation;

[0093] TL: trench line;

[0094] W: substrate;

[0095] 1: scribing tool.

Claims

1. A brittle material substrate processing method comprising: a scribing process in which, on a surface of a brittle material substrate, a scribing tool of a fixed blade is pressed and fixed at a position of the substrate that is apart from an end edge toward an inner side as a scribing starting point, and is moved in a loop and returned to the scribing starting point to process a scribe line in a manner of tracing a closed curve with a groove line that does not have a crack, and after a turning portion (K) with a radius of curvature of 0.5 mm or less is traced at a joint position that is the scribing starting point after the loop movement in succession to the scribe line, a separation scribe line is processed so as to induce a crack that travels in a thickness direction in a groove of the groove line.

2. The brittle material substrate processing method according to claim 1, wherein the closed curve includes a straight line portion and a curved line portion, and the joint position is included in the straight line portion.

3. The brittle material substrate processing method according to claim 2, wherein the separation scribe line is traced as a straight line after turning at the turning portion (K), and an angle formed by a straight line portion of the closed curve that includes the joint position and the straight line of the separation scribe line, which sandwiches the turning portion (K), is 20° to 90°.

4. The brittle material substrate processing method according to any one of claims 1 to 3, wherein the brittle material substrate is a glass substrate with a plate thickness of 200 μm or less.

5. A brittle material substrate dividing method comprising: a scribing process in which, on a surface of a brittle material substrate, a scribing tool of a fixed blade is pressed and fixed at a position of the substrate that is apart from an end edge toward an inner side as a scribing starting point, and is moved in a loop and returned to the scribing starting point to process a scribe line in a manner of tracing a closed curve with a groove line that does not have a crack, and after a turning portion (K) with a radius of curvature of 0.5 mm or less is traced at a joint position that is the scribing starting point after the loop movement in succession to the scribe line, a separation scribe line is processed so as to induce a crack that travels in a thickness direction in a groove of the groove line; and a breaking process in which a region surrounded by the closed curve is cut out by applying stress along the scribe line.

Images