Method for guiding crack in edge portion of donor substrate by using inclined laser beam

Abstract

The invention relates to a method for cutting solids wafers (1) off a donor substrate (2). The method comprises the following steps of: providing the donor substrate (2); producing at least one modification (10) in the interior of the donor substrate (2) by means of at least one laser beam (12), wherein the laser beam (12) penetrates the donor substrate (2) via a flat surface (16) of the donor substrate (2). The laser beam (12) is inclined with respect to the flat surface (16) of the donor substrate (2) such that it penetrates the donor substrate at an angle of not equal to 0 degree or 180 degrees relative to the longitudinal axis of the donor substrate. The laser beam (12) is focused in order to produce the modification (10) in the donor substrate (2) and the solids wafer (1) detaches itself from the donor substrate (2) as a result of the modifications (10) produced. Or a stress-inducing layer (14) is produced in or arranged on the flat surface (16) of the donor substrate (2) and mechanical stress is produced in the donor substrate (2) by exposing the stress-inducing layer (14) to heat. The mechanical stress produces a crack (20) for separating a solids layer (1), and the crack propagates along the modifications (10).

Description

technical field [0001] The invention according to claim 1 relates to a method for separating a solid sheet from a donor substrate. Background technique [0002] In many technical fields such as microelectronics or photovoltaics, materials such as silicon, germanium or sapphire are often used in the form of sheets and plates (so-called wafers). Conventionally, wafers of this type are currently produced by sawing from an ingot, wherein a relatively large loss of material occurs (“kerf loss”). Since the starting materials used are generally very expensive, there is a strong desire to produce such wafers more efficiently and cost-effectively with less material outlay. [0003] For example, with methods commonly used today, almost 50% of the material used is lost as "kerf loss" only in the production of silicon wafers for solar cells. On a worldwide basis, this corresponds to annual losses of more than 2 billion euros. Since the cost of the wafer accounts for the largest share...

AI Technical Summary

Problems solved by technology

[0007] It has been found that although it is possible to produce a modification in a solid at a distance from the edge of the solid with the aid of a laser beam, this is not readily possible in the region of the edge of the solid due to edge effects.

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