Semiconductor ingot inspecting method and apparatus, and laser processing apparatus

Abstract

Disclosed herein are a semiconductor ingot inspecting method and apparatus, and a laser processing apparatus. The inspecting method for a semiconductor ingot includes: a separation start point formingstep of locating a light-concentrating point of a laser beam with a permeability wavelength for the semiconductor ingot at a depth equivalent to the thickness of a to-be-produced wafer from an uppersurface, enabling the light-concentrating point and the semiconductor ingot to move relatively to apply the beam to the upper surface, and forming a separation start point formed by modified layers parallel to the upper surface and cracks extending from the modified layer; a light applying step of applying light from a light source to the upper surface of the semiconductor ingot according to a predetermined incidence angle specified relative to the upper surface, an imaging step of imaging a projected image formed by employing a reflected light of the light applied on the upper surface of thesemiconductor ingot in the light applying step and forming a shot image, the projected image showing the emphasis of asperities generated on the upper surface due to the formation of the modified layers and the cracks, and a determining step of comparing the formed shot image with preset conditions to determine the condition of the modified layers and the cracks.

Description

technical field [0001] The present invention relates to a semiconductor ingot inspection method, a semiconductor ingot inspection device, and a laser processing device. Background technique [0002] A functional layer is stacked on the front surface of a wafer made of silicon or the like, and various devices such as ICs and LSIs are formed on the functional layer in regions divided by a plurality of dividing lines. In addition, the wafer is divided into individual device chips by processing the planned dividing line of the wafer with a processing device such as a cutting device or a laser processing device, and the device chips obtained by dividing are widely used in various electronic devices such as mobile phones and personal computers. [0003] In addition, a functional layer is stacked on the front surface of a wafer made of a hexagonal single crystal such as SiC or GaN as a raw material, and the stacked functional layer is divided by a plurality of dividing lines formed...

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Problems solved by technology

[0015] According to the wafer production method described in Patent Document 3, a hexagonal single crystal ingot can be irradiated with a laser beam to efficiently form a separation origin composed of a modified layer and a crack inside the ingot. However, since the separation origin is formed inside the ingot , so it is difficult to detect from the outside of the ingot whether the separation origin is reliably formed before the wafer is separated from the ingot

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