TWI637922B - Chamfering method of glass substrate and laser processing device - Google Patents

Abstract

The present invention can perform chamfering in a simple manner, and can also chamfer the inner peripheral surface of an opening or the like of a glass substrate having an opening or the like.

The chamfering method of a glass substrate is a method of chamfering an end surface of a substrate by irradiating a glass substrate with laser light. The method includes a first step and a second step. The first step is to irradiate the laser light of the middle infrared light absorbed by the first main surface of the glass substrate and the inside from the first main surface side of the end portion of the glass substrate. In the second step, the laser light is scanned along the end of the glass substrate, and the edges of the first main surface side of the glass substrate and the second main surface side opposite to the first main surface are melted and chamfered.

Description

Chamfering method of glass substrate and laser processing device

The present invention relates to a method for chamfering a glass substrate, and in particular, to a method for chamfering a substrate end face by radiating laser light to a glass substrate and a laser processing device for realizing the chamfering method.

In IT (Information Technology, information technology) equipment, a large number of liquid crystal display devices are used, and a glass substrate is used in the liquid crystal display device. The glass substrate is cut into a specific shape by laser light, a scoring roller, or the like.

When transporting such a glass substrate or positioning the substrate during processing, there may be cracks or nicks on the end surface of the glass substrate due to impact or external force.

Therefore, in order to increase the strength of the end face of the glass substrate, the end face of the glass substrate is chamfered. This chamfering process is most often performed by grinding, but may be performed by laser light as shown in Patent Document 1.

The method shown in Patent Document 1 is as follows: laser light is irradiated from the front or back of the glass substrate, or both sides, and laser light is irradiated from a direction orthogonal to the end surface of the glass substrate to melt and chamfer the end surface of the glass substrate.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-35433

In the method of Patent Document 1, the laser light is preferably a CO ₂ laser having a wavelength of 10.6 μm. Then, the laser light is irradiated to the front and / or the back surface of the glass substrate, and the laser light is also irradiated to the end surface, and the end surface is heated to perform melting chamfering.

However, the method of Patent Document 1 must radiate laser light from at least two directions. Moreover, it is necessary to irradiate laser light from the direction substantially orthogonal to the end surface of a glass substrate. Therefore, the configuration of the apparatus for implementing the method becomes complicated. Furthermore, the method of Patent Document 1 cannot chamfer a cut surface (inner peripheral surface of an opening or a hole) of a glass substrate on which an opening or a hole is formed.

The object of the present invention is to allow chamfering in a simple manner and to chamfer the inner peripheral surface of an opening or the like of a glass substrate having an opening or the like.

The chamfering method of the glass substrate according to the first aspect of the present invention is to chamfer the end surface of the substrate by irradiating the glass substrate with laser light, and the method includes a first step and a second step. The first step is to irradiate the laser light of the middle infrared light absorbed by the first main surface of the glass substrate and the inside from the first main surface side of the end portion of the glass substrate. In the second step, the laser light is scanned along the end of the glass substrate, and the edges of the first main surface side of the glass substrate and the second main surface side opposite to the first main surface are melted and chamfered.

Here, the laser light of the mid-infrared light is irradiated from the first main surface side of the end portion of the glass substrate. The laser light of the mid-infrared light is not only absorbed by the first main surface of the glass substrate, but also reaches the inside of the substrate and the second main surface side opposite to the illuminated side, and heats the entire substrate. Thereby, the substrate end surface is melted and chamfered.

Therefore, the chamfering process can be performed only by irradiating laser light from the first main surface side of the glass substrate in a state where the glass substrate is placed on a stage. Further, the inner peripheral surface of the opening or the inner peripheral surface of the hole of the glass substrate having the opening or the hole may be chamfered.

In the chamfering method of the glass substrate in the second aspect of the present invention, the wavelength of the laser light is 2.7 μm or more and 5.5 μm or less.

In this method, the glass substrate is irradiated with a wavelength of 2.7 μm or more and 5.5 μm or less. Laser light of mid-infrared light. Since laser light of this wavelength can be absorbed while penetrating into the inside of the glass substrate, the deviation of the heat distribution from the first main surface to the inside and the second main surface of the glass substrate becomes smaller. Therefore, the entire end surface of the glass substrate is heated, and the edges on the front and back sides can be chamfered only by radiating laser light from the front side.

In the method of chamfering a glass substrate according to a third aspect of the present invention, in the first and second steps, the laser light is irradiated in such a manner that the inside is condensed at a certain distance from the end surface of the glass substrate.

Here, if laser light is irradiated to focus light on the end portion (edge portion) of the glass substrate, a crack may appear on the end portion of the glass substrate.

Therefore, in this method, the laser light is condensed and irradiated at a position where the inner side and the end surface of the glass substrate are separated by a specific distance. Therefore, the edge of the glass substrate can be chamfered without cracks.

In the chamfering method of the glass substrate according to the fourth aspect of the present invention, in the first and second steps, the laser light is irradiated in such a manner that the inside is spaced apart from the end surface of the glass substrate by 10 μm to 150 μm.

Here, if the condensing position of the laser light is less than 10 μm from the end surface to the inner side of the glass substrate, the probability of cracks at the end portion of the glass substrate becomes higher as described above. If the distance between the light-condensing position and the end surface exceeds 150 μm, the heat obtained by absorbing the laser light is not transmitted to the end portion, and the end portion cannot be heated sufficiently.

Therefore, in this method, the laser light is condensed and irradiated at a position separated from the end surface of the glass substrate by 10 μm or more and 150 μm or less inward.

In the chamfering method of the glass substrate of the fifth aspect of the present invention, in the first and second steps, the glass substrate is irradiated with a material selected from the group consisting of Er: Y ₂ O ₃ , Er: ZBLAN, Er: YSGG, Er: GGG, Er: YLF, Er: YAG, Dy: ZBLAN, Ho: ZBLAN, CO, Cr: ZnSe, Cr: ZnS, Fe: ZnSe, Fe: ZnS, semiconductor laser mid-infrared laser light group.

In the chamfering method of the glass substrate according to the sixth aspect of the present invention, the glass substrate has an internal absorption rate of laser light of 5% to 90%.

A laser processing device according to a seventh aspect of the present invention irradiates a glass substrate with laser light to perform chamfering of an end surface of the substrate. The device includes a table, a laser oscillator, and a laser light irradiation mechanism. A glass substrate is placed on the table. The laser oscillator oscillates the laser light of the mid-infrared light absorbed by the first main surface and the inside of the glass substrate. The laser light irradiation mechanism irradiates laser light from the laser oscillator from the first main surface side of the glass substrate placed on the table, scans the laser light along the end of the glass substrate, and The edges of the main surface side and the second main surface side opposite to the first main surface are melted and chamfered.

In the eighth aspect of the laser processing apparatus of the present invention, the laser oscillator oscillates laser light of mid-infrared light having a wavelength of 2.7 μm or more and 5.5 μm or less.

According to the present invention as described above, the chamfering can be performed in a simple manner, and the inner peripheral surface of the opening of a glass substrate having an opening or the like can also be chamfered.

1‧‧‧Workbench

2‧‧‧laser oscillator

3‧‧‧ Optical System

4‧‧‧platform mobile mechanism

6a, 6b, 6c‧‧‧Mirror

7‧‧‧ condenser lens

G‧‧‧ glass substrate

FIG. 1 is a schematic configuration diagram of a laser processing apparatus for implementing a method according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the wavelength of the laser light irradiated to the alkali-free glass, the reflectance, and the like.

3 (a) and 3 (b) are microscope photographs showing a cross section of an end surface of a glass substrate before chamfering and a cross section of an end surface of a glass substrate after chamfering.

[Laser processing device]

FIG. 1 shows a laser processing apparatus for implementing a chamfering method according to an embodiment of the present invention. The laser processing apparatus includes a table 1 on which a glass substrate G is placed, a laser oscillator 2, an optical system 3, and a platform moving mechanism 4 as a scanning mechanism. Laser light irradiation mechanism contains Optical system 3 and platform moving mechanism 4.

The laser oscillator 2 oscillates laser light of mid-infrared light having a wavelength of 2.7 μm or more and 5.5 μm or less. Here, as the laser oscillator 2, as long as it can emit a wavelength of 2.7 to 5.5 μm as described above and selected from Er: Y ₂ O ₃ , Er: ZBLAN, Er: YSGG, Er: GGG, Er: YLF, Er: YAG, Dy: ZBLAN, Ho: ZBLAN, CO, Cr: ZnSe, Cr: ZnS, Fe: ZnSe, FeZnS, laser light in the semiconductor laser mid-infrared laser light group. Here, the laser light emitted continuously oscillates.

The optical system 3 includes a plurality of mirrors 6 a, 6 b, and 6 c and a condenser lens 7. The condensing lens 7 is set so that laser light condenses near the surface of the glass substrate G.

The platform moving mechanism 4 is a mechanism for moving the table 1 in X and Y directions orthogonal to each other. With the platform moving mechanism 4, the light-condensing point can be scanned along a predetermined processing line.

[Processing method of glass substrate]

When chamfering the end surface of the glass substrate G using the above laser processing apparatus, the following steps are performed.

First, the glass substrate G to be processed is placed at a specific position on the table 1. Next, the glass substrate G on the table 1 is irradiated with the laser light of the mid-infrared light as described above, and the laser light is collected near the surface of the glass substrate G, and then the laser light is scanned along the end surface of the substrate. At this time, the light-condensing point of the laser light is set at a position which is 10 μm or more and 150 μm or less from the end surface of the glass substrate G to the inside (center) of the substrate.

By irradiating and scanning laser light as described above, the end face portion of the glass substrate is heated. In particular, the laser light is irradiated with the infrared light of the above-mentioned wavelength, and the laser light is absorbed while being transmitted to the inside of the glass substrate. Therefore, the end surface of the glass substrate is heated not only as the front side (first main surface) side of the irradiation surface of the laser light, but also inside the substrate and the back surface (second main surface) side are uniformly heated. Therefore, the end surface of the glass substrate is melted such that the center portion of the thickness of the substrate expands outward, and the edges on the front side and the back side are chamfered.

[Reflectivity and wavelength]

FIG. 2 shows the relationship between the wavelength, the reflectance, the transmittance, and the absorptance of laser light irradiated to a glass substrate having a thickness of 0.2 mm (for example, OA10 (product name: manufactured by Nippon Electric Glass Co., Ltd.)).

As can be seen from FIG. 2, for an alkali-free glass having a thickness of 0.2 mm, if the laser light has a wavelength of 2.8 μm, for example, the transmittance is about 80% (absorptance is about 20%). absorb. Therefore, the substrate end surface can be substantially uniformly heated from the front side to the rear side of the substrate end face, and the substrate end face can be melted and chamfered.

Based on the above description, it is estimated that the end face of most glass substrates can be chamfered by using laser light having a wavelength of 2.7 μm or more and 5.5 μm or less.

[Experimental example]

3 (a) and 3 (b) show a case where the end face of the glass substrate is chamfered when the glass substrate is irradiated with the laser light of the intermediate infrared light as described above. FIG. 3 (a) is a micrograph of a cross section of a substrate before laser light is irradiated, and FIG. 3 (b) is a cross-sectional view after processing with laser light. The glass substrate and laser irradiation conditions in this experiment are as follows.

Substrate: Alkali-free glass (OA10 = product name: made by Nippon Electric Glass Co., Ltd.), thickness = 0.2mm

Laser light: Er fiber laser, wavelength 2.8μm, power 4W, scanning speed 3mm / s, continuous oscillation

Condensing point: Condensing light at a position 30 μm from the end surface of the substrate toward the inside of the substrate, and near the surface of the substrate

In this experiment, the laser was scanned in the vertical direction on the paper surface of FIG. 3. As a result, as shown in FIG. 3 (b), the substrate end surface is melted, and a chamfered portion with an arc is formed from the central portion in the thickness direction to the front side and the back side.

[feature]

(1) The chamfering of the front side and the back side of the end surface can be performed only by irradiating the laser light of the mid-infrared light to the end surface of the glass substrate.

(2) By making the condensing point of the laser light a certain distance from the end surface to the inner side, it is possible to prevent the end portion from being cracked or chipped and chamfering.

(3) It is also possible to easily chamfer the inner peripheral surface of an opening or the inner peripheral surface of a hole to a glass substrate having an opening or a hole.

[Other embodiments]

The present invention is not limited to the embodiments described above, and various changes or modifications can be made without departing from the scope of the present invention.

In the above embodiment, laser light with continuous oscillation is used, but it is also possible to irradiate laser light with simulated continuous oscillation with a repetition frequency of 1 MHz or more or pulsed laser light with a frequency of 10 kHz or more.

In addition, the light-condensing position of the laser light is not limited to the position of the above-mentioned experimental example, as long as the light is condensed at a position of 10 μm or more and 150 μm or less inward from the end surface of the glass substrate.

Claims (6)

A method for chamfering a glass substrate is to irradiate a glass substrate with laser light and chamfer the end surface of the substrate. The method includes a first step of irradiating the glass substrate from the first main surface side of the end of the glass substrate. The first main surface and the internally absorbed laser light with a mid-infrared light having a wavelength of 2.7 μm or more and 5.5 μm or less; and a second step, which scans the laser light along the end of the glass substrate to make the glass substrate The edges of the first main surface side and the second main surface side opposite to the first main surface are melted and chamfered. For example, the chamfering method for a glass substrate according to claim 1, wherein in the above first and second steps, the glass substrate is irradiated with a member selected from the group consisting of Er: Y ₂ O ₃ , Er: ZBLAN, Er: YSGG, Er: GGG, Er: YLF, Er: YAG, Dy: ZBLAN, Ho: ZBLAN, CO, Cr: ZnSe, Cr: ZnS, Fe: ZnSe, Fe: ZnS, semiconductor laser mid-infrared laser light group any laser light. For example, the chamfering method for a glass substrate according to claim 1, wherein in the first and second steps, the laser light is irradiated in a manner of condensing light at a certain distance from the end surface of the glass substrate toward the inside. For example, the chamfering method for a glass substrate according to claim 3, wherein, in the first and second steps, the laser light is irradiated in a manner of condensing light at a position separated from an end surface of the glass substrate by 10 μm to 150 μm. The chamfering method for a glass substrate according to any one of claims 1 to 4, wherein the above-mentioned glass substrate has an internal absorption rate of laser light of 5% or more and 90% or less. A laser processing device is a method for chamfering an end surface of a substrate by irradiating a glass substrate with laser light, and includes: a table for placing a glass substrate; and a laser oscillator for making a first main surface of the glass substrate. And internally oscillated laser light of mid-infrared light having a wavelength of 2.7 μm or more and 5.5 μm or less; and a laser light irradiation mechanism that irradiates from the above-mentioned laser from the first main surface side of the glass substrate loaded on the table The laser light is emitted from the oscillator, and the laser light is scanned along the end of the glass substrate, and the edges of the first main surface side of the glass substrate and the second main surface side opposite to the first main surface are melted and performed. Chamfer.