Granted Patent B2

US 12,594,622 · App. 18/411,914 · Granted Apr 7, 2026

Inventors: Matthew Donofrio (Raleigh, NC); John Edmond (Durham, NC); Harshad Golakia (Morrisville, NC); Eric Mayer (Raleigh, NC)

Assignee: Wolfspeed, Inc.

B23K26/032B23K26/40B23K26/53B28D5/0064H01L21/02686

Abstract

Claims (34)

1 . A crystalline material processing method, comprising:

forming a subsurface laser damage region in a crystalline material substrate along a first average depth position below a surface of the crystalline material substrate;

generating an image of the surface of the crystalline material substrate;

analyzing the image of the surface of the crystalline material substrate to identify a condition indicative of one or more uncracked regions below the surface of the crystalline material substrate;

determining whether a property of the one or more uncracked regions exceeds a first threshold; and

adjusting one or more laser parameters for forming the subsurface laser damage region at a second average depth position below the surface of the crystalline material substrate.

2 . The crystalline material processing method of claim 1 , wherein the method further comprises:

determining whether a property of the one or more uncracked regions exceeds a second threshold; and

forming an additional subsurface laser damage region in the crystalline material substrate along the first average depth position below the surface of the crystalline material substrate.

3 . The crystalline material processing method of claim 1 , wherein the method further comprises fracturing the crystalline material substrate along the first average depth position.

4 . The crystalline material processing method of claim 1 , wherein the property of the one or more uncracked regions comprises an area of each of the one or more uncracked regions.

5 . The crystalline material processing method of claim 1 , wherein the property of the one or more uncracked regions comprises a maximum length dimension of each of the one or more uncracked regions.

6 . The crystalline material processing method of claim 1 , wherein the property of the one or more uncracked regions comprises a maximum width dimension of each of the one or more uncracked regions.

7 . The crystalline material processing method of claim 1 , wherein the property of the one or more uncracked regions comprises an aggregate area of the one or more uncracked regions.

8 . The crystalline material processing method of claim 1 , wherein the one or more laser parameters comprise one or more of laser power, focus depth, number of laser passes, laser pass spacing, or laser pulse width.

9 . The crystalline material processing method of claim 1 , wherein adjusting one or more laser parameters comprises incrementally increasing average laser power.

10 . The crystalline material processing method of claim 1 , wherein generating an image of the surface of the crystalline material substrate comprises:

illuminating the surface with a diffuse light source arranged to a first lateral side of the crystalline material substrate; and

capturing the image with an image capture device arranged to a second lateral side of the crystalline material substrate, the second lateral side opposing the first lateral side.

11 . The crystalline material processing method of claim 10 , wherein the first lateral side is within 5 degrees of perpendicular to a <11 2 0> direction of the crystalline material substrate.

12 . The crystalline material processing method of claim 1 , wherein the crystalline material substrate comprises silicon carbide.

13 . A crystalline material processing method, comprising:

forming with a laser a subsurface laser damage region in a crystalline material along a first average depth position below a surface of the crystalline material to effectuate separation of a portion of the crystalline material from a remaining crystalline material;

generating an image of the crystalline material;

analyzing the image to identify a condition indicative of one or more uncracked regions below the surface of the crystalline material;

adjusting one or more laser parameters of the laser based on analyzing the image; and

applying the laser with adjusted parameters to at least one of 1) uncracked regions of the crystalline material to effectuate separation of a portion of the crystalline material from the remaining crystalline material or 2) to the remaining crystalline material to form a second subsurface damage region below a surface of the remaining crystalline material.

14 . The crystalline material processing method of claim 13 , wherein the one or more laser parameters comprise one or more of laser power, focus depth, number of laser passes, laser pass spacing, or laser pulse width.

15 . The crystalline material processing method of claim 13 , wherein generating an image of the surface of the crystalline material comprises:

illuminating the crystalline material with a diffuse light source arranged to a first lateral side of the crystalline material;

capturing the image with an image capture device arranged to a second lateral side of the crystalline material, the second lateral side opposing the first lateral side.

16 . The crystalline material processing method of claim 15 , wherein the first lateral side is within 5 degrees of perpendicular to a <11 2 0> direction of the crystalline material.

17 . The crystalline material processing method of claim 13 , wherein the crystalline material comprises silicon carbide.

18 . The crystalline material processing method of claim 13 , wherein the method further comprises fracturing the crystalline material along the first average depth position.

Assignments (9)

Continuity (7)

References Cited (400)