# US 11,309,191 B2 · Method for modifying substrates based on crystal lattice dislocation density

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- Number: US 11,309,191 B2
- Document ID: US11309191B2
- Status: Granted
- Kind: B2
- Application number: 16/532,988
- Filed: 2019-08-06
- Published: 2020-02-13
- Granted: 2022-04-19
- Earliest claimed: 2018-08-07
- Assignees: Siltectra GmbH
- Applicants: Siltectra GmbH
- Inventors: Christian Beyer; Jan Richter; Ralf Rieske; Marko Swoboda; Albrecht Ullrich
- Web page: https://patentgrep.com/patent/US11309191B2

## CPC

- H10P 36/03: {within silicon bodies}
- B23K 26/53: for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
- B28D 5/0011: {with preliminary treatment, e.g. weakening by scoring}
- C30B 29/36: Carbides
- C30B 33/06: Joining of crystals
- H10P 52/00: Grinding, lapping or polishing of wafers, substrates or parts of devices
- H10P 54/00: Cutting or separating of wafers, substrates or parts of devices
- H10P 95/402: {of silicon bodies}
- B23K 2101/40: Semiconductor devices
- B23K 2103/56: {being semiconducting}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B28D: WORKING STONE OR STONE-LIKE MATERIALS
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR

## Abstract

A method includes: providing a semiconductor body having a generation plane and crystal lattice planes which intersect the generation plane at intersecting lines; generating modifications in the semiconductor body by multiphoton excitation and which are spaced apart from one another, the modifications altering a physical property of the semiconductor body so as to form subcritical cracks in the generation plane; and separating a solid-state layer from the semiconductor body by connecting the subcritical cracks in the generation plane.

## Claims

### Claim 1

A method, comprising:
providing a semiconductor body having a generation plane and crystal lattice planes which intersect the generation plane at intersecting lines;
generating modifications in the semiconductor body by multiphoton excitation and which are spaced apart from one another, the modifications altering a physical property of the semiconductor body so as to form subcritical cracks in the generation plane; and
separating a solid-state layer from the semiconductor body by connecting the subcritical cracks in the generation plane.

### Claim 2 (depends on 1)

The method of claim 1, wherein generating the modifications in the semiconductor body by multiphoton excitation comprises:
using a same polarization to form a group of modifications oriented in a same direction.

### Claim 3 (depends on 1)

The method of claim 1, wherein generating the modifications in the semiconductor body by multiphoton excitation comprises:
using a first polarization to form a first group of modifications oriented in a first direction; and
using a second polarization different than the first polarization to form a second group of modifications oriented in a second direction different than the first direction.

### Claim 4 (depends on 1)

The method of claim 1, wherein generating the modifications in the semiconductor body by multiphoton excitation comprises:
adjusting a polarization used to form a group of modifications so that an orientation of the modifications in the group deviate from one another.

### Claim 5 (depends on 1)

The method of claim 1, wherein generating the modifications in the semiconductor body by multiphoton excitation comprises:
adjusting a polarization for two or more groups of modifications so that the modifications of the at least two of the groups have an inclined orientation relative to the intersecting lines.

### Claim 6 (depends on 1)

The method of claim 1, wherein generating the modifications in the semiconductor body by multiphoton excitation comprises:
introducing laser radiation via a major surface into an interior of the semiconductor body to alter the physical property of the semiconductor body and form laser writing lines, each laser writing line corresponding to a group of the modifications.

### Claim 7 (depends on 6)

The method of claim 6, wherein the laser writing lines are inclined relative to the intersecting lines.

### Claim 8 (depends on 6)

The method of claim 6, wherein the semiconductor body is a silicon carbide wafer having a 4H polytype, the method further comprising:
rotating a line writing direction of the laser radiation by 30 °+/−3° relative to respective major axes of the silicon carbide wafer, such that a direction of the laser writing lines is oriented between two major axes of the silicon carbide wafer.

### Claim 9 (depends on 6)

The method of claim 6, wherein the semiconductor body is a cubic silicon carbide wafer, the method further comprising:
rotating a line writing direction of the laser radiation by 22.5°+/−3° relative to respective major axes of the cubic silicon carbide wafer, such that a direction of the laser writing lines is oriented between two major axes of the cubic silicon carbide wafer.

### Claim 10 (depends on 6)

The method of claim 6, wherein the semiconductor body is a gallium nitride wafer having a hexagonal wurtzite structure, the method further comprising:
rotating a line writing direction of the laser radiation by 30°+/−3° relative to respective major axes of the gallium nitride wafer, such that a direction of the laser writing lines is oriented between two major axes of the gallium nitride wafer.

### Claim 11 (depends on 6)

The method of claim 6, wherein introducing laser radiation via the major surface into the interior of the semiconductor body comprises:
placing individual laser shots at defined distances to form the laser writing lines.

### Claim 12 (depends on 6)

The method of claim 6, further comprising:
arranging the semiconductor body on a curved surface of a carrier unit such that the first surface of the semiconductor body into which the laser radiation is introduced has a concave or convex curvature.

### Claim 13 (depends on 6)

The method of claim 6, further comprising:
placing a pressing body between a source of the laser radiation and the semiconductor body, so that the laser radiation for generating the modifications, before entry into the semiconductor body, passes through the pressing body which is at least partly transparent for the laser radiation, the pressing body generating additional stresses in the semiconductor body which counteract propagation of the subcritical cracks.

### Claim 14 (depends on 1)

The method of claim 1, wherein separating the solid-state layer from the semiconductor body by connecting the subcritical cracks in the generation plane comprises:
applying an external force into the semiconductor body such that the subcritical cracks in the generation plane connect.

### Claim 15 (depends on 1)

The method of claim 1, wherein separating the solid-state layer from the semiconductor body by connecting the subcritical cracks in the generation plane comprises:
altering an amount of material on the generation plane by laser radiation such that the subcritical cracks in the generation plane connect.

### Claim 16 (depends on 1)

The method of claim 1, wherein the generation plane has regions with different modification concentrations.

### Claim 17 (depends on 6)

The method of claim 6, further comprising:
adjusting the energy of the laser radiation based on a dislocation density of the semiconductor body.

### Claim 18

A method, comprising:
providing a donor substrate having crystal lattice planes which are inclined relative to a planar major surface, the planar major surface forming a boundary of the donor substrate in a longitudinal direction of the donor substrate, with a crystal lattice plane normal being inclined in a first direction relative to a major-surface normal;
introducing laser radiation into an interior of the donor substrate by way of the major surface, such that a physical property of the donor substrate is altered in a region of at least one laser focus which is formed by laser beams emitted by a laser, the alteration of the physical property forming a structure through alteration of the site of penetration of the laser radiation into the donor substrate, a section of the structure that extends in a straight line being generated parallel to the major surface and extending in a second direction which, relative to the first direction, is inclined at an angle which is other than 90° , the altered physical property causing subcritical cracks to form in the donor substrate; and
removing a solid-state layer from the donor substrate by connecting the subcritical cracks in the donor substrate.

### Claim 19 (depends on 18)

The method of claim 18, wherein removing the solid-state layer from the donor substrate by connecting the subcritical cracks in the donor substrate comprises:
by introducing an external force into the donor substrate to connect the subcritical cracks.

### Claim 20 (depends on 18)

The method of claim 18, wherein removing the solid-state layer from the donor substrate by connecting the subcritical cracks in the donor substrate comprises:
altering material on a generation plane by laser radiation.

### Claim 21 (depends on 18)

The method of claim 18, wherein the major surface of the donor substrate forms part of the solid-state layer separated from the donor substrate.

### Claim 22 (depends on 18)

The method of claim 18, wherein the second direction is inclined relative to the first direction in an angle range between 45° and 87°.

### Claim 23 (depends on 18)

The method of claim 18, wherein the structure formed through alteration of the site of penetration of the laser radiation into the donor substrate is inclined relative to ends of the crystal lattice plane or relative to an intersecting line which arises at an intersection between a generation plane and the crystal lattice plane.

### Claim 24 (depends on 18)

The method of claim 18, further comprising:
rotating the donor substrate relative to the laser such that the structure formed through alteration of the site of penetration of the laser radiation into the donor substrate is generated in the form of an arc or is curved.

### Claim 25 (depends on 18)

The method of claim 18, further comprising:
adjusting the energy of the laser radiation based on a dislocation density of the donor substrate.