Laser processing device

Abstract

Provided is a laser processing device capable of performing processing at an appropriate spot interval when laser processing is performed by irradiating a laser beam. The laser processing device includes a chuck table that holds an object to be processed; a laser beam irradiation means for positioning a spot of the pulsed laser beam on the workpiece held by the chuck table and irradiating the pulsed laser beam to process the workpiece; and a control means for controlling the operation of the laser beam irradiation means. The laser beam irradiation unit includes a laser oscillator that oscillates a pulsed laser beam and emits a pulsed laser beam; an interlacing unit for interlacing the pulsed laser beam and adjusting the repetition frequency; a scanner that scans a spot of the pulsed laserbeam at a predetermined interval; and an f [theta] lens that focuses the pulsed laser light.

Description

technical field [0001] The present invention relates to a laser processing device that positions a spot of a pulsed laser beam on a workpiece held by a chuck table and irradiates it to perform processing. Background technique [0002] On the upper surface of an epitaxial substrate such as a sapphire substrate or a SiC substrate, a light emitting layer composed of an n-type semiconductor layer and a p-type semiconductor layer is formed by epitaxial growth via a buffer layer. For the light-emitting wafer formed with devices such as LEDs in each region divided by a plurality of planned dividing lines intersecting with the light-emitting layer, the planned dividing lines are divided together with the epitaxial substrate by laser light or the like to manufacture individual LED chips (for example, refer to Patent Document 1). [0003] In addition, in order to increase the brightness of LEDs and improve the cooling effect, a technique has been proposed in which a transfer substrat...

AI Technical Summary

Problems solved by technology

However, even if the operating frequency of the scanner is changed to keep the spot interval at a constant interval, depending on the repetition frequency of the pulsed laser beam, there will be a value exceeding the allowable value of the operating frequency of the scanner, and the actual scanner cannot be used. The operating frequency follows the hypothetical operating frequency, the spot interval is disordered, the buffer layer cannot be reliably damaged or the light-emitting layer is damaged.

In addition, it is not limited to the case where the peeling layer is formed on the above-mentioned laminated wafer. When the front surface of the workpiece is ground, the upper surface of the workpiece may be irradiated with laser light in a spiral shape in order to promote the grinding process. Also in this case, there is a problem that the laser processing performed on the upper surface of the workpiece is not uniform due to the inability to follow the operating frequency of the scanner as described above.

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