Method for producing short subcritical cracks in solid bodies

Patent metadata

Field	Value
Publication number	US-12539565-B2
Application number	US-201916971543-A
Country	US
Kind code	B2
Filing date	Feb 19, 2019
Priority date	Feb 20, 2018
Publication date	Feb 3, 2026
Grant date	Feb 3, 2026

Abstract

The invention relates to a method for producing modifications ( 9 ) in the interior of a solid body ( 1 ). The method comprises the introduction of laser radiation ( 14 ) of a laser ( 29 ) into the interior of the solid body ( 1 ) via a first surface ( 8 ) of the solid body ( 1 ). The solid body ( 1 ) forms a crystal structure. Modifications ( 9 ) are produced at predefined points in a production plane ( 4 ) in the interior of the solid body ( 1 ) by the laser radiation ( 14 ). The modifications ( 9 ) are closer to the first surface ( 8 ) than to a second surface, the second surface being parallel to the first surface ( 8 ). A plurality of linear forms ( 103 ) can be produced by the modifications ( 9 ). The solid body ( 1 ) cracks subcritically in the region of each modification ( 9 ). The subcritical cracks have an average crack length of less than 150 μm orthogonally to the direction of longitudinal extent of the linear form in question. Modifications ( 9 ) that belong to the same linear form ( 103 ) and that are produced one after the other are produced at a distance from each other that is defined by the function (d−x)/d<−0.31, where x>d.

First claim

The invention claimed is:

1 . A method for producing modifications in an interior of a solid body, the method comprising:
providing a laser; and introducing laser radiation from the laser into the interior of the solid body via a first surface of the solid body, the laser radiation producing modifications at predetermined locations on a production plane in the interior of the solid body, wherein the solid body forms a crystal structure, wherein the solid body has a second surface parallel to the first surface, wherein a plurality of linear shapes are produced by the modifications, wherein the solid body cracks subcritically in a region of each respective modification to form subcritical cracks, wherein the subcritical cracks have orthogonality to a direction of longitudinal extent of the respective linear shape and an average crack length of less than 150 μm, wherein the modifications that belong to the same linear shape and are successively produced are spaced at a distance from one another which is defined by: (d−x)/d<−0.31, wherein d is the diameter of a focal point of the laser radiation and x is the distance between adjacent focal points of the laser radiation, wherein x>d, wherein the distance between two directly adjacent linear shapes in each case is less than 50 μm.

2 . The method of claim 1 , wherein the laser radiation has a defined polarization, wherein the direction of polarization of the laser radiation is oriented at a defined angle or in a defined angle range with respect to a crystal axis of the solid body.

3 . The method of claim 1 , wherein the direction of longitudinal extent is aligned at a defined angle or in a defined angle range with respect to an intersecting line obtained at an intersection between the production plane and a crystal lattice plane of the solid body.

4 . The method of claim 1 , wherein producing the modifications comprises:
producing a first part of the modifications in the solid body during a first relative movement of the solid body with respect to an optics of the laser; and producing a second part of the modifications in the solid body during a second relative movement of the solid body with respect to the optics of the laser.

5 . The method of claim 4 , further comprising:
changing at least one setting of one laser parameter during the first relative movement compared to the second relative movement, wherein the first relative movement corresponds to a linear movement in a first direction and the second relative movement corresponds to a linear movement in a second direction, wherein the first direction and the second direction are oriented parallel to one another.

6 . The method of claim 1 , wherein the laser radiation is linearly polarized, elliptically polarized or circularly polarized.

7 . The method of claim 1 , further comprising:
arranging a diffractive optical element (DOE) in a path of the laser radiation, the DOE dividing up the laser radiation over a plurality of light paths to produce a plurality of focuses in the solid body.

8 . The method of claim 1 , wherein the solid body comprises crystal lattice planes that are inclined with respect to the first surface, wherein the first surface of the solid body forms one boundary in the longitudinal direction of the solid body, wherein a crystal lattice plane normal is inclined in a first direction with respect to a major-surface normal, wherein crystal lattice planes of the solid body are aligned in an inclined manner with respect to the production plane, and wherein the linear shapes are aligned in an inclined manner with respect to an intersecting line obtained at the intersection between the production plane and the corresponding crystal lattice plane.

9 . The method of claim 1 , wherein an amount of material of the solid body is altered, while forming a linear shape, such that ends of individual crystal lattice planes of the solid body are exposed by separation of solid body layers, and wherein the material alterations produce elevation or depression patterns for which a plurality of linear material alteration regions are produced.

10 . The method of claim 1 , further comprising:
moving the solid body in relation to the laser, wherein the laser is set continuously, in dependence on at least one parameter, for defined focusing of the laser radiation and/or for adapting the laser energy, wherein one parameter of the at least one parameter is a degree of doping of the solid body at a predetermined location or in a predetermined region.

11 . A method for producing at least one solid body layer, the method comprising:
carrying out the method of claim 1 ; and introducing an external force into the solid body, the force producing stresses in the solid body and/or producing an internal force in the solid body, wherein the external force and/or the internal force cause crack propagation along subcritical cracks and formation of a detachment region.

Assignees

• Siltectra Gmbh

Inventors

• Richter Jan
• Rieske Ralf
• Swoboda Marko
• Ullrich Albrecht

Classifications

• B23K2103/56

  being semiconducting · CPC title

• B23K2101/40

  Semiconductor devices · CPC title

• B23K26/0624

  using ultrashort pulses, i.e. pulses of 1 ns or less · CPC title

• B23K26/0006

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K26/032

  using optical means · CPC title