Patent ID: 11881407
Assignee: DENSO CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of manufacturing a chip formation wafer on which a semiconductor element is formed, the method comprising:
preparing a silicon carbide wafer made of silicon carbide and having a first main surface and a second main surface opposite to the first main surface;
forming an epitaxial film made of silicon carbide on the first main surface of the silicon carbide wafer to provide a processed wafer having one side adjacent to the epitaxial film and the other side made of the silicon carbide wafer;
irradiating a laser beam into the processed wafer from the other side of the processed wafer so as to form an altered layer along a surface direction of the processed wafer;
separating the processed wafer into a chip formation wafer having the one side of the processed wafer and a recycle wafer having the other side of the processed wafer with the altered layer as a boundary; and
reusing the recycle wafer as a silicon carbide wafer, wherein
the processed wafer has a beveling portion at an outer edge portion of the processed wafer,
an area of the other side is larger than an area of the one side in the beveling portion,
a depth from a boundary between the other side and the beveling portion to a side surface connecting the one side and the other side is shorter than a depth from the other side to the altered layer in a depth direction from the other side to the one side, in the preparing of the processed wafer, and
reusing the recycle wafer comprises
performing a chemical mechanical polishing process on the recycle wafer,
forming an epitaxial film on a surface of the recycle wafer, and
performing a shape adjustment process to form a beveling portion on the recycle wafer, wherein

an area of the recycle wafer after the shape adjustment process is performed is not less than an area of the processed wafer.