JP2009226725A - Laser scribing method of sapphire substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To scribe a sapphire substrate using low density laser beam. <P>SOLUTION: This laser scribing method is to scribe the sapphire substrate using laser beam, i.e. working the bite spot, of the sapphire substrate, into which the laser beam finds its way from outside the area of the sapphire substrate by high-density laser emission with a supersonic Q switch. Then, the scribing operation is performed using a CW laser in a low-density laser emission mode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for scribing a sapphire substrate.

  It has been conventionally performed to scribe a sapphire substrate having a semiconductor formed on the surface using a laser beam. Since the sapphire substrate has low light absorptance, the laser beam scanning speed was slowed, or the laser beam intensity was increased to increase the irradiation density and scribe. When processing with increased irradiation density, micro cracks are generated on the side of the scribe line due to the generated processing heat, affecting the semiconductor, so the so-called street width must be widened, and the use efficiency of the sapphire substrate decreases. It was. (See Patent Document 1)

  FIG. 5 shows a mother SOS substrate (hereinafter simply referred to as an SOS substrate) and a mother glass substrate (hereinafter simply referred to as a glass substrate) when a liquid crystal display element is formed using a mother SOS substrate having a semiconductor formed on the surface of a sapphire substrate. It is the front view stuck through the agent, and is an example in which 32 liquid crystal display elements are formed from the mother substrate.

  FIG. 6 is a schematic view illustrating a laser beam scanning method for scribing the SOS substrate. Scanning starts from the 0 point on the lower right, and scans up and down according to the arrows parallel to the C crystal axis of the sapphire single crystal. Subsequently, scanning is performed to the left and right parallel to the M crystal axis.

  FIG. 7 is a schematic diagram for explaining the scanning of the laser beam and is a side sectional view, but hatching is omitted for easy viewing. Reference numeral 1 denotes an SOS substrate, 2 denotes a glass substrate, and 3 denotes a pedestal. Although the laser beam is irradiated from the top to the bottom, A, B, and C are sequentially scanned in the direction of the hollow arrow. Since sapphire has a low light absorption rate, the laser beam is not absorbed when the irradiation density is low, and the laser beam focused on the surface of the SOS substrate 1 is transmitted and is not scribed.

  Therefore, a method has been devised in which a shallow groove is formed by irradiating the surface of the SOS substrate 1 with a laser beam having an increased irradiation density, and a laser beam having a lower irradiation density is irradiated again. 8 and 9 are schematic cross-sectional views for explaining the method, but hatching other than the processed portion is omitted for easy viewing.

  In FIG. 8, the laser beam whose irradiation density has been increased is irradiated in the direction of the hollow arrow from the right side to the left side of the drawing. Sapphire S1 on the surface of the SOS substrate 1 is processed shallowly and scribed along a scribe line. FIG. 10 is a schematic view after processing with a laser beam whose irradiation density has been increased by the Q switch, and is a front view. In order to irradiate the laser beam spot sequentially and sequentially, both sides of the scribe line are shaped into a circular arc connected shape. I'm hitting.

  In FIG. 9, the laser beam with the lowered irradiation density is scribed again along the scribe line formed in FIG. The processing depth in FIG. 8 is 5 μm to 10 μm, but in the second scribe S2, the irradiation density and scanning speed of the laser beam are selected so as to be about ½ of the thickness of the SOS substrate. Subsequent breaks include a method using thermal shock and a method using mechanical shock, and the method may be selected as appropriate.

Japanese Patent Laid-Open No. 61-30049

Since the first scribing is performed with a laser beam having a high irradiation density, a large amount of debris is generated.
2. It takes time to scribe the same part twice, which is inefficient. Also, the cut surface is dirty.

  In the scribing method using a laser beam on a sapphire substrate, the biting portion where the laser beam enters the sapphire substrate region from outside the sapphire substrate region is processed by high-density irradiation with an ultrasonic Q switch, and then scribed by low-density irradiation with a CW laser. The sapphire substrate scribing method is used.

  In the scribing method in which the scribing is performed on the grid, the high-density irradiation processing is a scribing method in only one direction (vertical or horizontal).

  Since the scribing portion other than the biting portion only needs to be scribed once, the working time can be shortened, and since there are few processed portions by high-density irradiation, the occurrence of debris is reduced. Since the actual cut part is scribed once by low density irradiation, the cut surface can be made clean.

  In the scribing method using a laser beam on a sapphire substrate, the biting portion where the laser beam enters the sapphire substrate region from outside the sapphire substrate region is processed by high-density irradiation with an ultrasonic Q switch, and then scribed by low-density irradiation with a CW laser. The sapphire substrate scribing method is used.

  1, 2, 3, and 4 are schematic cross-sectional side views for explaining a laser scribing method for an SOS substrate according to the present invention, but hatching other than a processed portion is omitted for easy viewing. . The reference numerals are common to the previous drawings, and the same reference numerals are the same.

In FIG. 1, reference numeral 1 denotes an SOS substrate, 2 denotes a glass substrate, and a semiconductor formed on the sapphire substrate is on a surface facing the glass substrate 2. Reference numeral 3 denotes a pedestal on which a workpiece is mounted for scribing with a laser beam. The pedestal is mounted on an XY table (not shown). The laser beam is irradiated from the top to the bottom, and is scanned in the C crystal axis direction indicated by a hollow arrow from the right to the left of the drawing. The laser device used in this example is SL412S manufactured by OMRON LASER FRONT Co., Ltd., and high density irradiation is Q switch pulse (50 KHz), scanning speed 100 mm / S, 0.5 W, spot diameter φ30 μm, power density: 26 × e13 W / m ² , electric field strength at this time: 1.306 × e8 V / m, low density irradiation is continuous irradiation, scanning speed is 40 mm / S, 16.3 W. First, as shown in FIG. 1, scribing S1 is performed for a length L = 5 mm from the end of the sapphire substrate in parallel with the C crystal axis by high-density irradiation (in the example shown in FIG. 6, seven locations). Next, similarly, scribe from the end of the sapphire substrate 1 (having a thickness of 600 μm) is about L = 5 mm in parallel with the M crystal axis (so as not to cover the liquid crystal display element region). Under the above conditions, the scribe depth is approximately 10 μm.

  Next, scribe S2 is performed by low-density irradiation as shown in FIG. Since the first scribe S1 is in the bite portion, scribe is possible even under the above conditions, and the depth of the scribe S2 reaches 300 μm. The scribe 2 can be formed without any problem even if the scribe advances and enters the portion without S1. When scribing parallel to the C crystal axis is completed, scribing is performed parallel to the M crystal axis.

  3 and 4 are diagrams showing the scribe in the M crystal axis direction, which is basically the same as the scribe in the C crystal axis direction. The only difference is that a scribe groove in the direction of the C crystal axis has already been formed. In this embodiment, the scribe S1 is formed. However, even if the scribe S1 is not formed, the scribe S2 in the M crystal axis direction always intersects with the scribe groove in the C crystal axis direction. You can scribe. As can be seen from FIG. 6, all the lines divided as the liquid crystal display element are scribed, so the object can be achieved.

  As described above, the scribe according to the present invention can achieve the above-described effects because all the scribes related to the liquid crystal display element can be irradiated with low density. Although the embodiment of the present invention has been described with the sapphire substrate of the liquid crystal display element, it goes without saying that the present invention is not limited to the scribing of the sapphire substrate of the liquid crystal display element.

Side surface sectional view with a schematic diagram for explaining a laser scribing method of an SOS substrate according to the present invention. Side surface sectional view with a schematic diagram for explaining a laser scribing method of an SOS substrate according to the present invention. Side surface sectional view with a schematic diagram for explaining a laser scribing method of an SOS substrate according to the present invention. Side surface sectional view with a schematic diagram for explaining a laser scribing method of an SOS substrate according to the present invention. Front view of SOS substrate and glass substrate attached via sealant Schematic illustrating a laser beam scanning method for scribing an SOS substrate It is a schematic diagram for explaining the scanning of the laser beam, a side sectional view Side sectional view with a schematic diagram for explaining the laser scribing method Side sectional view with a schematic diagram for explaining the laser scribing method Schematic view after processing with a laser beam with increased irradiation density by Q switch, front view

Explanation of symbols

1 SOS substrate 2 Glass substrate 3 Base S1 Scribe by high-density irradiation S2 Scribe by low-density irradiation

Claims (2)

  In the scribing method using a laser beam on a sapphire substrate, the biting portion where the laser beam enters the sapphire substrate region from outside the sapphire substrate region is processed by high-density irradiation with an ultrasonic Q switch, and then scribed by low-density irradiation with a CW laser. A scribing method for a sapphire substrate, characterized in that:   2. The scribing method according to claim 1, wherein the high-density irradiation processing is performed only in one direction (vertical or horizontal).

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