Wafer producing method
US9868177B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 29, 2017 |
| Grant date | Jan 16, 2018 |
| Priority date | — |
| Expiry date | Mar 29, 2037 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2103/56
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An SiC wafer is produced from an SiC ingot by a method that includes a first modified layer forming step and a second modified layer forming step. In the first step, a first laser beam having a first power forms a plurality of discrete first modified layers at a first depth inside the ingot. In the second step, a second laser beam having a second power greater than the first power is applied to the ingot with the second laser beam focused at a depth greater than the first depth. A beam spot of the second laser beam overlaps any one of the plural first modified layers, thereby continuously forming a plurality of second modified layers connected in a line at the first depth. Cracks are formed on both sides of the line of the plural second modified layers so as to extend along a c-plane in the ingot.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.