CN112192055A

CN112192055A - Laser processing method and laser processing apparatus

Info

Publication number: CN112192055A
Application number: CN202010649379.4A
Authority: CN
Inventors: 伊藤靖; 市川健一; 佐伯勇辉; 西部达矢
Original assignee: Via Mechanics Ltd
Current assignee: Via Mechanics Ltd
Priority date: 2019-07-08
Filing date: 2020-07-08
Publication date: 2021-01-08
Anticipated expiration: 2040-07-08
Also published as: JP7251904B2; TWI821580B; KR20210006294A; JP2021011410A; TW202103831A; CN112192055B

Abstract

The invention aims to detect that a hole is penetrated particularly when a glass substrate is perforated by laser. The solution is as follows: a laser processing apparatus includes: a table on which a substrate to be processed is placed; a laser irradiation system that irradiates the substrate with laser light; and a control unit for controlling each part of the apparatus for performing a machining operation; wherein the control section detects that the hole has penetrated by detecting that the light detection level at the end face of the substrate has decreased to a predetermined level during the processing operation.

Description

Laser processing method and laser processing apparatus

Technical Field

The present invention relates to a laser processing method and a laser processing apparatus, and particularly to a laser processing method and a laser processing apparatus capable of detecting that a hole has penetrated when a glass substrate is drilled with a laser beam.

Background

When drilling holes with laser, it is sometimes desired to reliably detect that a hole has been drilled. As means for verifying whether or not the machining operation is normally performed, for example, there are a method in which machining power is accumulated in each hole and compared with a predetermined value, as disclosed in patent document 1, or a method in which the reflection intensity at the time of laser irradiation is measured in each hole and compared with a predetermined value, as disclosed in patent document 2.

Patent document

Patent document 1: japanese laid-open patent publication No. 9-308977

Patent document 2: japanese patent laid-open publication No. 2004-9074

Disclosure of Invention

Problems to be solved by the invention

In the method, only whether the laser is normally irradiated is judged, and the method is not used for detecting that holes are formed or even holes are penetrated.

Accordingly, an object of the present invention is to detect that a hole has penetrated, particularly when a glass substrate is drilled with a laser beam.

Means for solving the problems

In a representative laser processing method disclosed in the present application, a through hole is drilled in a substrate by irradiating a laser beam, wherein a penetration of a hole is detected by detecting a light detection level at an end surface of the substrate during a processing operation, and detecting that the light detection level has decreased to a predetermined level.

Effect of the invention

According to the present invention, when a hole is formed in a glass substrate by a laser beam, it can be detected that the hole has penetrated.

Drawings

Fig. 1 is a diagram illustrating a penetration determination operation according to an embodiment of the present invention.

Fig. 2 is a schematic block diagram of a laser processing apparatus used in an embodiment of the present invention.

Fig. 3 is a diagram illustrating an example of drilling.

Fig. 4 is a cross-sectional view showing the shape of a hole machined in one embodiment of the present invention.

Description of the reference numerals

1 glass substrate

2 working table

4 control part

5 laser irradiation system

6 UV laser

8 optical sensor

9 end face

10 holes

Detailed Description

An embodiment of the present invention will now be described.

Fig. 2 is a schematic block diagram of a laser processing apparatus used in an embodiment of the present invention. The respective components and connecting lines mainly indicate those considered necessary for explaining the present embodiment, and do not indicate all the necessary elements as a laser processing apparatus.

In fig. 2, a glass substrate 1 is placed on a stage 2 of a laser processing apparatus through an adsorption jig 3, and a plurality of holes are drilled by irradiating UV laser 6 from a laser irradiation system 5 under the control of a control unit 4 that controls the operation of each part of the apparatus.

The adsorption jig 3 performs the following functions: the glass substrate 1 is sucked from below through the suction holes 7 provided in the glass substrate, and is prevented from floating. The control unit 4 makes the following: is configured to be centered on a programmed processing device, and has control functions other than those described herein, and is also connected to blocks not shown.

The constitution described so far is a constitution well known in the art. Reference numeral 8 denotes an optical sensor which is disposed in contact with the end surface 9 of the glass substrate 1 and detects the amount of light refracted by the end surface 9. In this case, the optical sensor 8 may have a plurality of photodetecting elements arranged along the end surface 9 of the glass substrate 1 to improve sensitivity.

The control unit 4 can determine the penetration state of the hole based on a detection signal from the optical sensor 8, as will be described later.

The control unit 4 can drill a through hole by continuously irradiating a plurality of places with laser light around the position where the hole is to be drilled by controlling the operation of each part of the apparatus (hereinafter, the machining of continuously irradiating a plurality of places at one hole position is referred to as drilling).

As a method of drilling, there is a method of gradually changing the position so as to draw a spiral (helical) trajectory, and a method described later: as shown in fig. 3, after repeating the laser irradiation S so as to draw a circle with the center P of the position where the hole is to be formed as the center, the same repetition is performed while gradually changing the radius of the circle.

When the UV laser beam 6 is irradiated onto the glass substrate 1, the UV laser beam 6 is refracted inside the glass substrate 1 and enters the end surface 9 of the glass substrate 1. Fig. 4 (a) shows that when irradiation to the glass substrate 1 is started, the refracted light to the end surface 9 of the glass substrate 1 is strong at this time. However, as the process progresses thereafter, the refracted light to the end face 9 also gradually decreases because the glass portion at the hole position gradually decreases. Fig. 4(b) shows a state where the hole 10 penetrates.

The light refracted toward the end surface 9 of the glass substrate 1 does not change only at the start of irradiation and at the time of penetration, but also changes depending on the hole position or the number of holes penetrated.

In this embodiment, the output level (hereinafter referred to as "through level") of the optical sensor 8 in the through state is detected for all the hole positions by a prior experiment or the like, and the lowest output level (hereinafter referred to as "lowest through level") is grasped, whereby it is determined that the hole has been penetrated when the output level gradually decreases to reach the lowest through level as the drilling process progresses.

Since the through-hole level varies depending on the hole position, or depending on the position or number of the through-holes, the through-holes can be detected reliably at any hole position by determining that the through-holes have been formed when the through-holes reach the lowest through-hole level.

Fig. 1 is a diagram for explaining a penetration determination operation in the control unit 4.

Fig. 1(a) shows a state of one hole position in the glass substrate 1. The control section 4 monitors the output level V of the optical sensor 8 at the start of irradiation of the UV laser beam 6, and determines that the hole has penetrated when the output level V gradually decreases to reach the minimum penetration level L as the drilling process progresses.

When the control unit 4 determines that the hole has been penetrated, the laser irradiation system 5 stops the irradiation of the laser beam to the hole position and starts the irradiation of the laser beam to the next hole position.

Fig. 1(b) shows a state in which the glass substrate 1 has another hole. Here, the control section 4 monitors the output level V of the optical sensor 8 at the start of irradiation of the UV laser beam 6, and determines that the hole has penetrated when the output level V gradually decreases to reach the minimum penetration level L as the drilling process progresses.

When the control unit 4 determines that the hole has been penetrated, the laser irradiation system 5 stops the irradiation of the laser beam to the hole position and starts the irradiation of the laser beam to the next hole position in the same manner as described above.

In the above embodiment, by grasping the lowest penetration level L in advance, when the output level V gradually decreases to reach the lowest penetration level L as the drilling process progresses, it is determined that the hole has penetrated, but it may be determined that the hole has penetrated by another method.

For example, it is possible to detect how much the output level V of the optical sensor 8 at the time of penetration is lowered from the output level V of the optical sensor 8 at the time of starting laser irradiation (hereinafter referred to as a penetration ratio) by a predetermined experiment or the like, grasp the lowest ratio (hereinafter referred to as a lowest penetration ratio), and determine that the hole has penetrated when the output level V is gradually lowered to reach the lowest penetration ratio as the drilling process progresses. In this method, the penetration is reliably detected at any hole position, and therefore, it is determined that the hole has penetrated when the penetration ratio is the lowest.

Incidentally, in the case of this method, the output level V of the optical sensor 8 immediately after the start of laser irradiation may be selected instead of the output level V of the optical sensor 8 at the start of laser irradiation. Further, if the output level V at the time of penetration is overwhelmingly smaller than that before penetration, the output level of the optical sensor 8 may be selected at a time immediately after the start of laser irradiation.

Incidentally, in the above embodiment, as long as the size, the hole position, the hole size, the hole opening order, and the specification of the glass material of the glass substrate 1 are not changed, the lowest penetration level L or the lowest penetration ratio is naturally the same. Therefore, it is not necessary to grasp the minimum penetration level L or the minimum penetration ratio of the glass substrate 1 having each hole in advance, and the standard of one glass substrate 1 may be grasped within a range where the above specification does not change.

However, if it is desired to avoid a slight change in each glass substrate 1, the minimum penetration level L or the minimum penetration ratio of each lot may be grasped in advance, for example.

Further, in the above embodiment, the description was made on the case where the drilling processing by the UV laser 6 was performed, but in the present invention, CO may be used₂Instead of the UV laser 6, a laser may be used to perform so-called punching; the punching process is a process in which one irradiation is performed to one hole position or a plurality of irradiations are performed to the same place.

Claims

1. A laser processing method for drilling a through hole in a substrate by irradiating a laser beam, wherein a light detection level at an end surface of the substrate during a processing operation is detected, and the penetration of the through hole is detected by detecting that the light detection level has decreased to a predetermined level.

2. A laser processing method for drilling a through hole in a substrate by irradiating a laser beam, wherein a light detection level at an end face of the substrate during a processing operation is detected, and penetration of the hole is detected by detecting that the light detection level is lowered to a predetermined ratio with respect to a level of the hole before penetration.

3. The laser processing method according to claim 2, wherein the pre-penetration is defined as when the laser irradiation is started.

4. A laser processing apparatus is characterized by comprising: a table on which a substrate to be processed is placed; a laser irradiation system that irradiates the substrate with laser light; and a control unit for controlling each part of the apparatus for performing a machining operation;

the control unit detects that the hole has been penetrated by detecting that the light detection level at the end surface of the substrate has decreased to a predetermined level during the processing operation.

5. A laser processing apparatus is characterized by comprising: a table on which a substrate to be processed is placed; a laser irradiation system that irradiates the substrate with laser light; and a control unit for controlling each part of the apparatus for performing a machining operation;

the control unit detects that the hole has been penetrated by detecting that the light detection level at the end surface of the substrate during the machining operation has decreased to a predetermined ratio with respect to the level of the hole before the penetration.

6. The laser processing apparatus according to claim 5, wherein the pre-penetration is defined as when the laser irradiation is started.