JP7255890B2 - Processing method and cutting method for brittle material substrate - Google Patents

Description

The present invention relates to a processing method and a cutting method for brittle material substrates such as glass substrates used for display panels such as liquid crystal displays (LCDs) and organic EL displays (OLEDs) for mobile terminals, solar cell panels and the like. In particular, the present invention relates to a dividing method for forming a dividing groove that forms a closed curve in a brittle material substrate and cutting out odd-shaped products surrounded by this closed curve. In this specification, the term "deformed shape" refers to a shape including curved lines other than straight lines, and a product cut out in a shape surrounded by closed curves including curved portions other than straight lines is referred to as a deformed product.

In the method of cutting a glass substrate, etc., linear grooves are formed on the substrate surface by scribing the surface of the substrate with a cutter wheel, which is a rotating blade, or the cutting edge of a scribing tool with a sharp fixed blade. . The grooves are notches formed by plastically deforming the substrate surface, and the linear grooves are called "scribe lines".

In this specification, a scribing tool refers to a tool that uses a sharp fixed blade such as a diamond blade instead of a rotary blade to form grooves for plastic deformation on a substrate.

When cutting out from the brittle material substrate W a region surrounded by a closed curve consisting of a quadrangle in which the four corners are rounded by arcs with a relatively large curvature radius of about 2 to 10 mm as shown in FIG. 4, a cutter wheel (rotary blade ) or a scribing tool (fixed blade) is used to start scribing from the position of the starting point P on the surface of the brittle material substrate W, and the scribing is performed so as to draw the above-mentioned square (one round), and the position of the starting point P is touched again. A closed curve scribe line SL1 is processed. Then, following the closed-curve scribe line SL1, a separation scribe line SL2 passing through the starting point P and extending in a straight line to the substrate edge N is formed in a single stroke.

As shown in FIG. 6(b), the scribe line can be accompanied by a crack C extending directly downward from the scribe line SL at the same time when the scribe line is engraved. A scribe line with this crack C is called a "crack line CL" here.

If the crack line CL with this crack C is formed, in the subsequent breaking step, by applying mechanical stress such as bending the substrate or applying thermal stress such as local heating, The crack C of the crack line CL progresses in the thickness direction, completely dividing the substrate, and the odd-shaped product A surrounded by the closed curve can be cut out.

Formation of such a crack line CL requires a trigger (originating crack) as its starting point. The trigger can be easily formed by riding the cutting edge of a scribing tool or cutter wheel (rotating blade) over the edge of the substrate (from the outside of the substrate). This is because the edges of the substrate are locally damaged by the impact when the cutting edge rides on them. Furthermore, by moving the edge of the blade on the surface of the substrate, the crack line CL can be extended from the trigger in the moving direction of the edge of the blade. A scribing method for scribing including the edge of the substrate, such as scribing by rolling a cutter wheel from the edge of the substrate, is referred to as “outer cutting”. On the other hand, a scribing method in which a scribing starting point is set at a position away from the edge of the substrate toward the inner side of the substrate is called "inner cutting".

Some methods of forming the trigger do not rely on the riding of the cutting edge on the edge of the substrate. For example, a vibration generating member is attached to the scribing head that holds the scribing tool or cutter wheel, and the cutting edge is pressed against the scribing starting point (the starting point for "inner cutting") that is separated from the substrate edge toward the inside of the substrate. can be formed by vibrating and applying an impact to the substrate (see Patent Document 1).

However, in the case of any of the above conventional methods, if the impact between the cutting edge and the substrate is stronger than necessary when processing the trigger, damage to the cutting edge, occurrence of chipping at the edge of the substrate, cracking of the substrate, etc. Therefore, there is a problem that the scribing conditions such as the moving speed of the cutting edge and the load on the cutting edge during scribing are greatly restricted.

Therefore, the present applicant previously proposed a processing method as shown below in Patent Document 2.
That is, first, using a scribing tool with a fixed blade or a cutter wheel, scribing is performed from a point near one edge of the substrate surface to a point near the other edge so as not to include the edge, and a crack C is formed. A shallow groove-shaped scribe line SL (see FIG. 6A) is formed. As a result, scribing can be performed without applying a strong impact at the scribing start point, and a groove-like scribe line SL without cracks C can be reliably processed. Hereinafter, the shallow groove-like scribe line SL (see FIG. 6A) without cracks C is referred to as "trench line TL".

Next, at a position near one end of the trench line TL, in Patent Document 2, an "assist line" is formed by scribing a cutting edge in a direction perpendicular to the trench line TL. At this time, on the side of the trench line TL near the intersection of the assist line and the trench line TL, the crack C progresses in the thickness direction and is induced (see FIG. 6B). Since the crack C can be extended along the trench line TL with the intersection position as the starting point trigger, the crack line CL can be formed.

According to the above processing method, when processing the first scribe line, it is not necessary to form a scribe line with a crack C (that is, a crack line CL). range (degree of freedom) expands to the low load side. That is, if the trench line TL is formed without cracks C, scribing can be relatively easily performed with a small scribing load. As a result, there is no risk of cracking the substrate due to excessive scribing load. In particular, the thinner the substrate, the more difficult it is to crack, and this is very effective in processing a glass substrate of 200 μm or less. Moreover, since scribing along the trench line TL enables high-quality processing with few scratches, the processing quality is improved over the entire circumference. In addition, since the load is low, wear and damage to the cutting edge can also be suppressed.

JP-A-2000-264656 Japanese Patent No. 6249091

Therefore, even when a deformed product A surrounded by a closed curve as shown in FIG. 4 is cut out from a brittle material substrate, it is possible to first form a scribe line to be drawn as a trench line and then induce a crack to change it into a crack line. desirable. That is, after the closed curve scribe line SL1 is processed as a trench line TL without cracks, the trench lines TL are changed to crack lines CL with cracks C. FIG.

Specifically, using a cutter wheel or a scribing tool, start scribing from the position of the starting point P for "inner cutting", rotate it so as to draw a square, and reconnect at the position of the starting point P to form a closed-curve scribe line. Process SL1. This circulating scribe line scribes as a trench line without cracks. A trench line near the starting point P can be changed into a crack line CL with a crack C. FIG. Further, following the scribe line SL1, a scribe line SL2 for separation extending in a straight line from the position of the starting point P (hereinafter, the position of the starting point P after the circular movement is also referred to as the contact point P) to the substrate end N is written in one stroke. form with

However, according to experiments, when the scribing process is performed by the above method, when the odd-shaped product A is cut out by applying stress in the breaking process, as shown in the enlarged view of FIG. It was found that stepped burrs B (also called horns B) were generated in the vicinity of the . This is because when the linear separation scribe line SL2 is processed from the position of the contact point P, it passes through the vicinity of the already processed closed curve scribe line SL1, and this vicinity is scribed in the first round of scribing. It is considered that the burr B is generated because the generated stress remains and the line overlaps at the branched portion with the contact point P or a small crack occurs. Such burrs B significantly deteriorate the processing quality of products and become a major factor in the generation of defective products.

Therefore, the present invention solves the problem of burr generation that occurs when a scribe line is processed along a closed curve and then breaks, suppresses the generation of burrs when cutting odd-shaped products from a brittle material substrate, and achieves a high yield. It is an object of the present invention to provide a processing method for a brittle material substrate that can cut out a non-defective product.

A method of processing a brittle material substrate according to the present invention, which has been devised to solve the above problems, is to use a scribing tool with a fixed blade on the surface of the brittle material substrate, with a position spaced inward from the edge of the substrate as a scribing starting point. It is pressed and moved around so as to draw a closed curve with a trench line without cracks, returned to the scribe start point to process the scribe line, and is continued to the scribe line so that it is 0.5 mm or less at the scribe start point position. A scribing step is performed in which a separating scribe line is processed after turning by drawing a turning portion K having a radius of curvature of , so that a crack proceeding in the thickness direction is induced in the groove of the trench line.

According to the present invention, since the scribe line is formed as a trench line without cracks, it is possible to select a scribing condition with a lower load than when processing as a scribe line with cracks, and it is possible to process with an excessive load. It is possible to eliminate defects such as cracks due to
In addition, using a scribing tool that can be turned with a small radius of curvature, it is moved around to draw a closed curve, and when it touches the trench line at the scribing start point, By drawing an arc-shaped turning portion K with a small curvature radius of 0.5 mm or less, the separating scribe line is drawn so as to be immediately separated from the closed curve, so the separating scribe line is positioned immediately after the contact point. can be separated from the scribe line of the closed curve. Therefore, in the vicinity of the intersection of the separation scribe line and the closed curve scribe line, it is less susceptible to the effects of each residual stress, making it possible to suppress the generation of burrs on the closed curve scribe line. It can be kept as small as possible.

In the above invention, the closed curve may include a straight portion and a curved portion, and the contact position may be included in the straight portion.
Since a turning portion K having a radius of curvature of 0.5 mm or less is drawn at the contact position and the scribe line for separation reaches the edge of the substrate after being turned, even if the contact (starting point) position is provided in a straight portion, The separating scribe line can be immediately separated from the closed curve scribe line. If the point of contact (starting point) is provided on the straight line portion in this way, the turning point of the separating scribe line can be obtained regardless of the shape of the corner portion (curved portion) of the odd-shaped product to be cut, regardless of the shape of the corner. The radius of curvature of K can be set.
Here, the separating scribe line is drawn in a straight line after being turned at the turning portion K, and the straight portion including the contact position of the closed curve with the turning portion K interposed therebetween and the separating scribe line The bending angle with the straight line may be 20° to 90°.
In order for the separating scribe line to have a linear shape that facilitates breaking, it is necessary not to overlap the straight line portion of the closed curve, so that it is not parallel to the straight line portion of the closed curve. According to verification experiments to be described later, it was found that the bending angle should be specifically set to 20° to 90°.

In the above invention, the brittle material substrate may be a glass substrate having a thickness of 200 μm or less.
According to the present invention, even a glass substrate having a thickness of 200 μm or less, which is technically difficult to cut, can be cut while suppressing the generation of burrs.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the scribing process of 1st Embodiment of the method of this invention, Fig.1 (a) shows the whole board|substrate, FIG.1(b) is a figure which expands and shows a part. It is an explanatory view showing the scribing step of the second embodiment of the method of the present invention. FIG. 4 is a diagram showing an example of a scribing tool used in the present invention; FIG. 4 is an explanatory diagram showing an experimental division method for verification by the inventors of the present invention. FIG. 5 is an enlarged view for explaining a division result by the division method of FIG. 4; FIG. 6(a) shows a scribe line (trench line) without cracks C formed in the substrate, and FIG. 6(b) is a cross-sectional view showing a scribe line (crack line CL) including cracks C. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below based on the drawings. Substrates to be processed according to the present invention include glass substrates, ceramic substrates, silicon substrates, compound semiconductor substrates, sapphire substrates, and quartz substrates. It is a thin substrate, especially a thin glass substrate having a thickness of 200 μm or less.

In this embodiment, a scribing tool 1 shown in FIG. 3 is used. The scribing tool 1 includes a cutting edge portion 1b made of a member in the shape of a truncated quadrangular pyramid supported by a holder 1a. 1e (fixed blade) is formed.
Note that the cutting edge portion 1b can also be formed as a polygonal truncated pyramid such as a triangular truncated pyramid or a pentagonal truncated pyramid instead of the square truncated pyramid. Further, the cutting edge portion 1e can be formed by forming a top surface and a ridgeline at the corners of the prismatic or polygonal plate-like cutting edge portion 1b.

Next, the dividing method of this embodiment will be described.
<Embodiment 1>
The following scribing process is performed as the first stage of dividing the substrate. As a scribing step, as shown in FIG. 1, a scribing tool 1 is used to process the surface of a glass substrate W (hereinafter simply referred to as substrate) to form a scribe line SL1 drawn as a square closed curve with rounded corners. Specifically, a shallow groove-like trench line (Fig. 6(a)) starts scribing. Then, the scribing tool 1 is circularly moved so as to draw the above-mentioned square, and the scribing line SL1 of the trench line is processed until it touches again at the position of the starting point P1 (hereinafter, the position of the starting point P1 after circular movement is the contact point P1 also called).

In the scribing step, an arc-shaped turning portion K having a small curvature radius R of 0.5 mm or less is drawn from the position of the point of contact P1, continuing from the scribing line SL1, which is a closed curve completed at the point of contact P1, in the scribing direction. , the separation scribe line SL2 reaching the edge of the substrate is processed in a single stroke. Here, by using the scribing tool 1 having a fixed blade with a sharpened tip, it is possible to turn the turning portion K with a sufficiently smaller radius of curvature R than that of the rotating blade. Specifically, the radius of curvature R is 1 mm to 0.1 mm, and it is also possible to turn with a radius of curvature R smaller than 0.1 mm by sharpening the cutting edge.

The separating scribe line SL2 after turning at the turning portion K is made to reach the edge of the substrate W. As shown in FIG. In the trench line in contact with the edge of the substrate W in this way, a crack progressing in the thickness direction is induced in the groove of the trench line near the edge of the substrate W, and the crack line CL (Fig. 6(b)) accompanies the crack C. )). The separating scribe line SL2 in this portion is preferably drawn as a straight line so that it can be easily broken in the next breaking step. However, it can be curved as long as it does not interfere with the break.
Depending on environmental conditions and scribing conditions, the crack C may be formed short only near the edge of the substrate W, or may be formed long along the separation scribe line SL2 and the closed-curve scribe line SL1. However, in any case, it is sufficient that the cracks are induced at least in the vicinity of the edges because the trench lines can be reliably extended over the entire trench line by applying stress thereafter.

Further, when the separating scribe line SL2 is drawn in a straight line, the straight line portion including the contact point P1 of the scribe line SL1 (the straight line portion in contact with the turning portion K at the contact point P1) sandwiching the turning portion K, and the separating scribe line In order to suppress burrs, it is particularly preferable that the bending angle α between the line SL2 and the straight line is in the range of 20° to 90°.

Then, after the crack lines CL with cracks are formed at the edge portions of the substrate W of the separation scribe lines SL2, the substrate is mechanically bent, or heat such as light irradiation, thermal heat, or cold jet is applied. In addition, a breaking step is performed to apply stress to the substrate to cut out from the scribe line SL2, and further cut out the odd-shaped product A surrounded by a closed curve along the scribe line SL1.

According to the above method, since the scribe line SL1 is processed as a trench line without cracks, a lower scribe load can be selected than when processing a scribe line with cracks from the beginning. In addition, since the separating scribe line SL2 is provided with a turning portion that turns from the contact point P1 with a small curvature radius R of 0.5 mm or less, it can be separated from the closed curve at the position immediately after the contact point, and the scribe line of the closed curve can be formed. When separating along the line, the influence of the scribe line for separation and the area where the stress remains in the vicinity of the scribe line for separation is less likely to be affected. As a result, the occurrence of burrs can be suppressed.

(Verification experiment 1)
Verification purpose: The starting point (point of contact) P1 of the scribe line SL1 of the closed curve is set near the center of the straight line portion of the closed curve, and the curvature radius R of the turning portion K branching from the straight line portion of the scribe line SL1 of the closed curve and turning is set as a variable parameter. Then, the size of the burr generated when the linear separation scribe line SL2 extending to the edge is processed is verified (see FIG. 1).
Substrate thickness: 50 μm
Pressing force of scribing tool: 1.3N
Scribing speed: 10 mm/sec (turning part 0.1 mm/sec)
Bending angle: fixed at 90° Curvature radius of turning part K: 10 mm, 1 mm, 0.5 to 0.1 mm

Table 1 shows the verification results. As for the judgment of quality as an irregularly shaped product, burrs with a size of 15 μm or more are considered defective, 15-5 μm as good, and less than 5 μm as best.

As seen in Table 1, there was a tendency that the smaller the curvature radius R, the smaller the burr size. In particular, when the radius of curvature was set to 0.4 mm or less, the effect of suppressing burrs became remarkable.

<Embodiment 2>
Scribing is performed by the scribing tool 1 in the same manner as in the first embodiment, but the starting point (point of contact) P1 of the scribe line SL1 of the closed curve is set at the end of the straight portion of the scribe line SL1 of the closed curve, that is, the rounded corner (corner curve part), and circular movement is performed to machine a closed-curve scribe line SN1 that touches at the position of the point of contact P1. Then, the separating scribe line continues to the scribe line SN1 and extends straight from the position of the contact point P1 to the substrate end N1 at a bending angle of preferably 20° to 90° after turning at the turning portion having the curvature radius R. Form SL2 in a single stroke.
In this embodiment as well, the generation of burrs can be suppressed as in the first embodiment.

(Verification experiment 2)
Verification purpose: The starting point (point of contact) P1 of the scribe line SL1 of the closed curve is the end of the straight portion of the scribe line SL1 of the closed curve (the boundary position with the curved portion of the corner), and the straight portion of the separation scribe line SL2 and the closed curve The bending angle α formed by the straight portion of the scribe line SL1 is used as a variable parameter to verify the relationship with the size of the generated burr (see FIG. 2).
Substrate thickness: 50 μm
Pressing force of scribing tool: 1.3N
Scribing speed: 10 mm/sec (turning part 0.1 mm/sec)
Curvature radius of turning part K: fixed at 0.1 mm Bending angle α: 0°, 20°, 45°, 70°, 90°

Table 2 shows the verification results. As for the judgment of quality as an irregularly shaped product, burrs with a size of 15 μm or more are considered defective, 15-5 μm as good, and less than 5 μm as best.

As can be seen in Table 2, except for the case where the bending angle is 0° (corresponding to the conventional example in FIG. 4), the burr is 2 μm for all angles from 20° to 90°, and the effect of suppressing burrs is remarkable. there were.
Although illustration is omitted, even when the position of the starting point (contact point) is the center of the straight portion as in Verification Experiment 1, the judgment of "good" or more is possible when the bending angle α is in the range of 20 ° to 90 °. Yes, it has a suppressive effect.

Although representative examples of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above. For example, in the above embodiment, a substrate having a thickness of 50 μm was used, but the present invention can be applied even when the thickness of the substrate exceeds 100 μm. Also, the pressing force of the scribing tool may be reduced at the turning portion.
Further, in the above-described embodiment, the separation scribe line SL2 reaches the edge of the substrate W, thereby inducing a crack progressing in the thickness direction in the groove of the trench line. may be formed so as to intersect the separation scribe line SL2. In this case, the separating scribe line SL2 can be formed at a location away from the edge of the substrate W. FIG. By crossing the separation scribe line SL2 and the assist line, a crack in the assist line is induced from the intersection of the separation scribe line SL2, and the trench line of the separation scribe line SL2 changes to the crack line CL with the crack C. do.
Furthermore, the present invention can be modified and changed as appropriate without departing from the scope of the claims while achieving the object thereof.

INDUSTRIAL APPLICABILITY The present invention can be used when cutting odd-shaped products from brittle material substrates such as glass substrates.

A Odd-shaped product to be cut C Crack CL Crack line K Bending corner N1 Board edge P1 Scribing start point (intersection point)
SL scribe line
SL1 closed curve scribe line SL2 separation scribe line TL trench line W substrate 1 scribing tool

Claims (5)

A scribing tool with a fixed blade is pressed against the surface of the brittle material substrate with a position spaced inward from the edge of the substrate as the starting point for scribing, and the scribing tool is circularly moved so as to draw a closed curve with a trench line that does not involve cracks. Returning to the starting point, processing a scribe line, continuing with the scribe line, drawing a turning portion K having a radius of curvature of 0.5 mm or less at the position of the scribing start point, and processing a separating scribe line after turning. and a scribing step for inducing cracks progressing in the thickness direction in the grooves of the trench lines. 2. The method of processing a brittle material substrate according to claim 1, wherein the closed curve includes a straight line portion and a curved line portion, and the scribe start point position is included in the straight line portion. The separating scribe line is drawn as a straight line after turning at the turning portion K, and the straight line portion including the scribe start point position of the closed curve with the turning portion K interposed therebetween and the straight line of the separating scribe line. 3. The method for processing a brittle material substrate according to claim 2, wherein the bending angle between the two is 20° to 90°. The method for processing a brittle material substrate according to any one of claims 1 to 3, wherein the brittle material substrate is a glass substrate having a thickness of 200 µm or less. A scribing tool with a fixed blade is pressed against the surface of the brittle material substrate with a position spaced inward from the edge of the substrate as the starting point for scribing, and the scribing tool is circularly moved so as to draw a closed curve with a trench line that does not involve cracks. Returning to the starting point, processing a scribe line, continuing with the scribe line, drawing a turning portion K having a radius of curvature of 0.5 mm or less at the position of the scribing start point, and processing a separating scribe line after turning. and a scribing step for inducing cracks progressing in the thickness direction in the grooves of the trench lines;
and a breaking step of cutting out the region surrounded by the closed curve by applying stress along the scribe line.

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