Method for forming a crack in an edge region of a donor substrate

A method for separating a solid-body layer from a donor substrate, said method comprising:

• providing a donor substrate having a planar surface, a normal axis orthogonal to the planar surface, and a peripheral surface;
• producing a first plurality of modifications within the donor substrate by means of at least one first LASER beam, wherein the at least one first LASER beam penetrates the donor substrate via the planar surface;
• producing a second plurality of modifications within the donor substrate by means of at least one second LASER beam, wherein the at least one second LASER beam penetrates the donor substrate via the peripheral surface at an angle not equal to 90° relative to the normal axis of the donor substrate;
• and
• producing stresses in the donor substrate to produce a crack for separating the solid-body layer, wherein the crack propagates along the first and second pluralities of modifications.

A method for separating a solid-body layer from a donor substrate, said method comprising:

• providing a donor substrate having a planar surface, a normal axis orthogonal to the planar surface, and a peripheral surface;
• producing a plurality of modifications within the donor substrate using at least one LASER beam, wherein the at least one LASER beam penetrates the donor substrate via the peripheral surface, wherein a first portion of the at least one LASER beam penetrates the donor substrate at a first angle relative to the normal axis and at least one further portion of the at least one LASER beam penetrates the donor substrate at a second angle relative to the normal axis, wherein the value of the first angle differs from the value of the second angle, wherein the first portion and the at least one further portion of the at least one LASER beam are focused in order to produce the modifications in the donor substrate;
• and
• producing stresses in the donor substrate to produce a crack for separating the solid-body layer, wherein the crack propagates along the plurality of modifications.