Laser processing device

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device which allows a configuration forming two light-condensing points above and below and a configuration forming one light-condensing point to be selected.SOLUTION: Laser beam irradiation means for irradiating an object W to be processed with a laser beam is provided with: a laser beam oscillator 62; output adjustment means 63 for adjusting output of the laser beam; a condenser 64 for condensing the laser beam and irradiating the object to be processed with the laser beam; a 1 / 2 wavelength plate 65 disposed between the output adjustment means and the condenser; polarization angle adjustment means 66 for adjusting a polarization angle of the laser beam passing the 1 / 2 wavelength plate; and control means for controlling the polarization angle adjustment means. The condenser is provided with a birefringent lens 642 and an objective condenser lens 643. The control means controls the polarization angle adjustment means to adjust a polarization angle of the laser beam passing the 1 / 2 wavelength plate and appropriately changes a light condensing point of the laser beam condensed by the objective condenser lens via the birefringent lens into two configurations and one configuration.

Description

technical field [0001] The present invention relates to a laser processing apparatus for forming a modified layer inside a workpiece such as a semiconductor wafer by irradiating laser beams which are transparent to the workpiece. Background technique [0002] In the manufacturing process of a semiconductor device, a plurality of regions are divided by divisional lines called streets arranged in a grid on the surface of a substantially disk-shaped semiconductor wafer, and ICs, LSIs, etc. are formed on the divided regions. device. Then, by cutting the semiconductor wafer along the lanes, the regions in which the devices are formed are divided to manufacture individual semiconductor chips. In addition, the optical device wafer obtained by stacking light-receiving elements such as photodiodes and light-emitting elements such as laser diodes on the surface of the sapphire substrate is also divided into individual optical devices such as photodiodes and laser diodes by cutting al...

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Problems solved by technology

[0008] However, in the laser processing apparatus disclosed in the above-mentioned Patent Document 2, there is no problem when there are a plurality of modified layers to be formed, but when an odd number of modified layers is formed, too many focused points Excessive light spots cause ablation on the upper surface of the wafer, leading to problems such as quality degradation

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