TWI656102B - Breaking method of brittle substrate - Google Patents

Abstract

The invention discloses a method for breaking a fragile substrate. Even if the breaking position of the fragile substrate is specified in advance, the fragile substrate can be prevented from being accidentally broken before the time when the fragile substrate should be broken. In the present invention, the scoring wheel 51 is rotated while applying a load F to thereby form a trench line TL on the glass substrate 4. The scoring wheel 51 travels in the same direction DP as the direction of the in-plane component Fi of the load F. The process of forming the trench line TL is performed to obtain a crack-free state. A crack in the thickness direction DT of the glass substrate 4 is extended along the trench line TL in the traveling direction, thereby forming a crack line CL. By the crack line CL, the continuous connection of the glass substrate 4 directly below the trench line TL in the direction crossing the trench line TL is disconnected. The glass substrate 4 is cut along the crack line CL.

Description

Breaking method of brittle substrate

The present invention relates to a method for cutting a fragile substrate, and more particularly to a method for cutting using a scribing wheel.

In the manufacture of electrical devices such as flat display panels and solar panels, it is often necessary to break fragile substrates such as glass substrates. First, a scribe line is formed on the substrate, and then the substrate is broken along the scribe line. The scribe line can be formed by mechanically processing the substrate with a knife edge. A trench is formed by plastic deformation on the substrate by sliding or rotating the blade tip on the substrate, and at the same time, a vertical crack is formed directly below the trench. Thereafter, a stress application called a breaking step is performed. The crack is completely advanced in the thickness direction by the cutting process, thereby cutting the substrate.

In most cases, the step of cutting the substrate is performed immediately after the step of forming a scribe line on the substrate. However, there is also a proposal for processing the substrate between the step of forming the scribe line and the breaking step. The process of processing a substrate is, for example, a process in which some components are provided on a substrate.

For example, according to the technique of International Publication No. 2002/104078, in the method of manufacturing an organic EL display, a scribe line is formed on a glass substrate for each area that becomes each organic EL display before the cover is installed. Therefore, it is possible to avoid the problem that the cover contacts the glass cutter when the scribe line is formed on the glass substrate after the cover is provided.

In addition, for example, according to the technology of International Publication No. 2003/006391, in a method of manufacturing a liquid crystal display panel, two glass substrates are bonded to each other after forming a scribe line. With this, can Enough to cut two brittle substrates at the same time in one cutting process.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] International Publication No. 2002/104078

[Patent Document 2] International Publication No. 2003/006391

According to the above-mentioned prior art, the processing of the fragile substrate is performed after the scribe line is formed, and thereafter the breaking process is performed by applying a stress. This means that there are already vertical cracks when processing fragile substrates. It may happen that during the processing, the vertical crack is further extended in the thickness direction, which causes the brittle substrate that should be integrated during processing to be separated. In addition, in the case where the substrate processing step is not performed between the step of forming the scribe line and the step of cutting the substrate, it is usually necessary to transport or store it after the step of forming the scribe line and before the step of cutting the substrate. The substrate may be accidentally cut off at this time.

The present invention has been made to solve the problems as described above, and an object thereof is to provide a method for breaking a fragile substrate, which can prevent the fragile substrate from being broken at a time when the fragile substrate is broken even in a predetermined breaking position of the fragile substrate. It was accidentally broken before.

The method for cutting a fragile substrate of the present invention uses a scoring wheel having an outer peripheral portion around a rotation axis, a blade point is provided on the outer peripheral portion, and the following steps are performed.

A brittle substrate having a first surface and a second surface opposite to the first surface and having a thickness direction perpendicular to the first surface is prepared.

Next, by applying a load to the scribe wheel, while pressing the outer periphery of the scribe wheel on the first surface of the fragile substrate, the scribe wheel is rotated on the first surface of the fragile substrate, thereby allowing the The first surface is plastically deformed to form a trench line having a trench shape. The load has an in-plane component parallel to the first surface of the fragile substrate. In the step of forming the trench line, the scoring wheel travels on the first surface in the same direction as the in-plane component direction. The process of forming the trench line is performed to obtain a state in which the brittle substrate is continuously connected in a direction crossing the trench line directly below the trench line, that is, a state without cracks.

Next, a crack in the thickness direction of the brittle substrate is extended along the trench line in the direction of travel, thereby forming a crack line. By the crack line, the continuous connection of the fragile substrate directly below the trench line in a direction crossing the trench line is disconnected.

Second, the brittle substrate is cut along the crack line.

According to the present invention, a ditch line having no cracks formed immediately below is used as a line defining a breaking position of the fragile substrate. The crack line used as the direct beginning of the break is formed by extending the crack along the trench line after forming the trench line. With this, the brittle substrate after the trench line is formed and before the crack line is formed, even if the breaking position is specified by the trench line, the crack line is not easily broken because the crack line has not been formed yet. By using this state, it is possible to prevent the fragile substrate from being accidentally broken before the point at which the fragile substrate should be broken, even at a predetermined breaking position of the fragile substrate.

4‧‧‧ glass substrate / brittle substrate

50‧‧‧ cutting appliances

51‧‧‧ Scribing Wheel

52‧‧‧pin

53‧‧‧ fixed frame

AL‧‧‧Auxiliary line

AX‧‧‧Rotary axis

CL‧‧‧ Rift Line

DC‧‧‧ direction

DP‧‧‧ Direction of travel

DT‧‧‧thickness direction

ED1‧‧‧side

ED2‧‧‧side

F‧‧‧Load

Fi‧‧‧ in-plane ingredients

Fp‧‧‧ vertical composition

MS‧‧‧ Surface shape

N1‧‧‧ starting point

N2‧‧‧ Halfway

N3‧‧‧ Finish

PF‧‧‧ Peripheral Department

RT‧‧‧ Arrow

SF1‧‧‧upper / first

SF2‧‧‧bottom surface / 2nd surface

TL‧‧‧Ditch Line

FIG. 1 is a side view schematically showing the configuration of a cutting tool used in the method for cutting a brittle substrate in FIG. 1.

2 (A) and 2 (B) are a front view (A) schematically showing the configuration of a scoring wheel and a pin, and a partially enlarged view (B) of FIG. 2 (A).

FIG. 3 is a flowchart schematically showing a configuration of a method for cutting a fragile substrate in Embodiment 1 of the present invention.

4 (A) and 4 (B) are plan views schematically showing the first and second steps of the method for breaking a fragile substrate in Embodiment 1 of the present invention.

FIG. 5 (A) and FIG. 5 (B) are ends showing the structure of the trench line formed in FIG. 4 (A). The top view (A) and the end view (B) of the structure of the crack line formed in FIG. 4 (B).

6 (A) and 6 (B) are plan views schematically showing a method for breaking a brittle substrate in a modified example of the first embodiment of the present invention.

FIG. 7 is a plan view schematically showing a method for cutting a brittle substrate in Embodiment 2 of the present invention.

FIG. 8 is a plan view schematically showing a method for cutting a brittle substrate in Embodiment 3 of the present invention.

FIG. 9 is a plan view schematically showing a method for breaking a brittle substrate in Embodiment 4 of the present invention.

Hereinafter, embodiments of the present invention will be described based on the drawings. In the following drawings, the same or corresponding parts are given the same reference signs, and descriptions thereof will not be repeated.

(Embodiment 1)

Referring to FIG. 1, FIG. 2 (A), and FIG. 2 (B), first, the cutting tool 50 used in the method for cutting the glass substrate 4 (brittle substrate) according to this embodiment will be described below.

The cutting tool 50 is mounted on a scoring head (not shown) to move the glass substrate 4 relatively, thereby scoring the glass substrate 4. The cutting tool 50 includes a scoring wheel 51, a pin 52, and a fixing frame 53. The scoring wheel 51 has a substantially disk-like shape, and its diameter is typically around several mm. The scoring wheel 51 is fixed to the fixed frame 53 via a pin 52 and is rotatable about a rotation axis AX.

The scoring wheel 51 has an outer peripheral portion PF provided with a cutting edge. The outer peripheral portion PF extends in a ring shape around the rotation axis AX. As shown in FIG. 2 (A), the outer peripheral portion PF is ridge-like and steep at a visual level, thereby constituting a cutting edge including a ridge and an inclined surface. On the other hand, at the microscope level, in the part that actually works because the scoring wheel 51 penetrates into the glass substrate 4 (below the two-point chain line in FIG. 2 (B)), the ridge line of the outer peripheral portion PF has a fine Surface shape MS. In the front view (FIG. 2 (B)), the surface shape MS preferably has a curved shape and the curved shape has a limited radius of curvature. Scribing wheel 51 is made of superhard alloy, sintered diamond, polycrystalline diamond or single crystal It is made of hard materials such as diamond. From the viewpoint of reducing the surface roughness of the ridgeline and the inclined surface, the entire scribe wheel 51 can be made of single crystal diamond.

Next, referring to the flow shown in FIG. 3, a method for cutting the substrate 4 using the cutting tool 50 will be described below.

1 and 4 (A), a glass substrate 4 having an upper surface SF1 (first surface) and a lower surface SF2 (second surface opposite to the first surface) is prepared (FIG. 3: Step S10). The glass substrate 4 has a thickness direction DT perpendicular to the upper surface SF1. In FIG. 4, the glass substrate 4 has edges ED1 and ED2 facing each other.

Next, the scoring wheel 51 is rotated on the upper surface SF1 of the glass substrate 4 (FIG. 1: arrow RT), whereby the scoring wheel 51 travels on the upper surface SF1 in the traveling direction DP. The traveling by the rotation is performed by applying a load F to the scoring wheel 51 while pressing the outer peripheral portion PF of the scoring wheel 51 on the upper surface SF1 of the glass substrate 4. Thereby, plastic deformation occurs on the upper surface SF1 of the glass substrate 4 to form a trench line TL having a trench shape (FIG. 3: Step S20).

The load F has a vertical component Fp parallel to the thickness direction DT of the glass substrate 4 and an in-plane component Fi parallel to the upper surface SF1. The direction of travel DP is the same as the direction of the in-plane component Fi.

Referring to FIG. 5 (A), the above-mentioned step of forming the trench line TL is performed in order to obtain a state in which the glass substrate 4 is continuously connected in a direction DC that intersects the trench line TL directly below the trench line TL. No cracks. In the crack-free state, although the trench line TL has been formed by plastic deformation, a crack along the trench line has not been formed. Therefore, even if a torque is applied to the glass substrate 4, the break along the trench line does not easily occur. In order to obtain a crack-free state, it is sufficient that the vertical component Fp is not excessively increased (FIG. 1).

In FIG. 4 (A), the ditch line TL is formed from the starting point N1, passing through the halfway point N2 to the ending point N3. The trench line TL should be formed away from the edge of the upper surface SF1. Thereby, the scoring wheel 51 does not need to contact the edge of the upper surface SF1.

Referring further to FIG. 4 (B), an auxiliary line AL is formed next. Use this as a starting point, along the ditch The line TL forms a crack line CL (FIG. 3: Step S30).

Referring to FIG. 5 (B), by the crack line CL, the glass substrate 4 is directly below the trench line TL in a direction DC crossing the extending direction of the trench line TL (the lateral direction of FIGS. 4 (A) and (B)). The continuous connection is disconnected. In other words, the so-called "continuous connection" here is a connection that is not interrupted by cracks. In addition, in a state where the continuous connection is disconnected as described above, each part of the glass substrate 4 can also contact each other through the crack of the crack line CL. The crack line CL is formed by extending a crack (see FIG. 5 (B)) in the thickness direction DT of the glass substrate 4 along the trench line TL in the traveling direction DP.

The auxiliary line AL is formed so as to be in contact with the trench line TL on the upper surface SF1 of the glass substrate 4. In this embodiment, it is formed so as to cross the trench line TL. Since the auxiliary line AL is a general scribe line, it is accompanied by a crack that penetrates in the thickness direction DT of the glass substrate 4. The cutting tool 50 used to form the trench line TL may also be used to assist the formation of the line AL, but at this time, a larger load than the load F when the trench line TL is formed is required. In addition, in order to form the auxiliary line AL more reliably, other devices may be used. For example, a scribing wheel provided with an uneven shape along the outer peripheral portion PF may be used. With the above apparatus, the auxiliary line AL with deeper cracks can be easily formed. Furthermore, as shown in FIG. 4 (B), when the auxiliary line AL starts at a position far away from the edge of the glass substrate 4 (so-called incision), a crack can be more reliably generated.

The formation of the crack line CL is believed to have begun by strain release of internal stress near the trench line TL. Specifically, it is considered that the internal stress is released by the stress applied to the glass substrate 4 when the auxiliary line AL is formed. It is considered that the process that is the beginning of the formation of the crack line CL may be any process that is the beginning of the release of internal stress, and is not limited to the formation process of the auxiliary line AL described above.

According to the study by the present inventors, it is more difficult to form the crack line CL from the halfway point N2 toward the starting point N1 than from the halfway point N2 toward the end point N3. That is, there is a so-called direction dependency, that is, when the ditch line TL is formed, the crack line CL tends to travel toward the scribing wheel 51 Stretch in the same direction as DP. The reason is considered to be due to the above-mentioned internal stress distribution.

Next, in step S40 (FIG. 3), the glass substrate 4 is cut along the crack line CL in a so-called cutting step. The breaking step can be performed, for example, by applying an external force to bend the glass substrate. In addition, when the crack line CL travels completely in the thickness direction DT during its formation, the formation of the crack line CL and the breaking of the glass substrate 4 may occur simultaneously. In the above case, the breaking process can be omitted.

According to the present embodiment, a trench line TL (FIG. 5 (A)) without a crack immediately below is formed as a line defining the breaking position of the glass substrate 4. The crack line CL (FIG. 5 (B)) used as the direct beginning of the breaking is formed by extending the crack along the trench line after forming the trench line TL. With this, the glass substrate 4 (FIG. 4 (A)) after the trench line TL is formed and before the crack line CL is formed, even though the position where the glass substrate 4 is to be broken is specified by the trench line TL, it is still not formed along the trench line Crack-free state of TL cracks. As long as no excessive stress is applied to the glass substrate 4, the crack-free state can be easily maintained. Therefore, during this crack-free state, the glass substrate 4 can be stably stored, transported, and film-formed and etched on the glass substrate 4 without being accidentally generated.

According to this embodiment as described above, by using the crack-free state, even if the breaking position of the glass substrate 4 is specified in advance, the glass substrate 4 can be prevented from being accidentally broken before a desired point in time.

The step of forming the crack line CL in this embodiment is substantially different from the generation of cracks in the so-called breaking step. The breaking step is to further extend the formed cracks in the thickness direction, thereby completely separating the substrate. On the other hand, the formation process of the crack line CL is accompanied by a qualitative change, that is, from a crack-free state obtained by the formation of the trench line TL to a state having a crack along the trench line TL. This change is thought to occur through the release of internal stresses in a crack-free state.

Next, a modified example of this embodiment will be described. 6 (A), only auxiliary lines are formed In AL, a crack line CL along the trench line TL may not be formed. Referring to FIG. 6 (B), even in this case, the glass substrate 4 can be separated along the auxiliary line AL, whereby the crack line CL can be formed.

In addition, the auxiliary line AL of this modification can also be formed by the same method as the crack line CL described above. That is, after the trench line is formed, it may be formed by forming a crack along the trench line.

(Embodiment 2)

The same is true of the method for breaking the glass substrate 4 in this embodiment. First, a trench line TL is formed on the upper surface SF1 of the glass substrate 4 by the same method as in the first embodiment (FIG. 4 (A)).

Referring to FIG. 7, an auxiliary line AL is formed next on the lower surface SF2 of the glass substrate 4. The auxiliary line AL crosses the ditch line TL in a planar arrangement. In this embodiment, since the auxiliary lines AL and the trench lines TL are formed on different surfaces of the glass substrate 4, they are not in direct contact with each other.

Next, similarly to FIG. 6 (B) of the first embodiment, the glass substrate 4 is separated along the auxiliary line AL. This starts the formation of the crack line CL. Thereafter, as in the first embodiment, the glass substrate 4 is divided along the crack line CL.

(Embodiment 3)

In the cutting method of the glass substrate 4 in this embodiment, first, a trench line TL is formed on the upper surface SF1 of the glass substrate 4 by the same method as in the first embodiment (FIG. 4 (A)).

Referring to FIG. 8, the auxiliary line AL is formed on the upper surface SF1 of the glass substrate 4 so as to partially overlap the trench line TL. In the figure, the auxiliary line AL is formed in the ditch line TL so as to coincide with a portion between the start point N1 and the halfway point N2 and be far from the end point N3. The length of the auxiliary line AL is, for example, about 0.5 mm. Starting from the formation of the auxiliary line AL, a crack line CL is formed.

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

(Embodiment 4)

In the cutting method of the glass substrate 4 in this embodiment, first, a trench line TL is formed on the upper surface SF1 of the glass substrate 4 by the same method as in the first embodiment (FIG. 4 (A)).

Referring to FIG. 9, a part of the trench line TL is irradiated with laser light. In the figure, a portion of the trench line TL between the start point N1 and the halfway point N2 and far from the end point N3 is irradiated with laser light. Thereby, a crack line CL is formed in the portion between the starting point N1 and the halfway point N2 in the trench line TL. From this, a crack line CL is formed from the halfway point N2 toward the end point N3.

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

The method for cutting a brittle substrate in each of the above embodiments is particularly suitable for a glass substrate, but the brittle substrate may be made of a material other than glass. For example, ceramics, silicon, compound semiconductors, sapphire, or quartz can also be used as materials other than glass.

Claims (7)

A cutting method for a fragile substrate, which uses a scoring wheel, the scoring wheel has an outer peripheral portion around a rotation axis, a knife tip is provided on the outer peripheral portion, and includes a step of preparing a brittle substrate, the brittle substrate Having a first surface and a second surface opposite to the first surface, and having a thickness direction perpendicular to the first surface; and a step of forming a ditch line by applying a load to the scribe wheel while scoring the scribe The outer peripheral portion of the wheel is pressed against the first surface of the fragile substrate, and while the scoring wheel is rotated on the first surface of the fragile substrate, plastic deformation occurs on the first surface of the fragile substrate, thereby Forming a trench line having a groove shape; the load has an in-plane component parallel to the first surface of the brittle substrate; in the process of forming the trench line, the scoring wheel faces inwardly with the first surface on the first surface The components travel in the same direction, and the process of forming the trench line is performed in order to obtain a state in which the brittle substrate is in a direction crossing the trench line directly below the trench line. The continuously connected state is a crack-free state; the method further includes a step of forming a crack line, which causes a crack in the brittle substrate in the thickness direction to extend along the trench line in the direction of travel, thereby forming a crack line; In the aforementioned crack line, the continuous connection of the fragile substrate directly below the trench line in a direction crossing the trench line is disconnected; and further comprising a step of breaking the fragile substrate along the crack line. For example, the method for breaking a brittle substrate according to claim 1, wherein the step of forming the aforementioned crack line includes a step of forming an auxiliary line, the auxiliary line accompanying a crack penetrating in the aforementioned thickness direction of the aforementioned brittle substrate, and The first surface is connected to the ditch line. The method for breaking a brittle substrate according to claim 2, wherein in the step of forming the auxiliary line, the auxiliary line is formed on the first surface of the brittle substrate so as to cross the trench line. The breaking method of the brittle substrate according to claim 3, wherein the step of forming the crack line includes a step of separating the brittle substrate along the auxiliary line. The method for breaking a brittle substrate according to claim 2, wherein in the step of forming the auxiliary line, the auxiliary line is formed on the first surface of the brittle substrate so as to partially overlap the trench line. For example, the method for breaking a fragile substrate according to claim 1, wherein the method further includes a step of forming an auxiliary line on the second surface of the fragile substrate, in a planar layout, the auxiliary line crosses the trench line, and forms the aforementioned The step of the crack line includes a step of separating the fragile substrate along the auxiliary line. For example, the method for breaking a brittle substrate according to claim 1, wherein the step of forming the crack line includes a step of irradiating a part of the trench line with laser light.