Patents by Inventor Yuuichirou Mukai

Yuuichirou Mukai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5851924
    Abstract: A method for fabricating a semiconductor wafer to reduce the number of processing steps and produce low-cost wafers in a short time is disclosed. The method involves surface grinding both the front surface and back surface of a single-crystal silicon wafer which has been sliced from a rod and chamfered. In the surface grinding step, the size numbers of abrasive grains are larger than #2000 for front surface grinding, and smaller than #600 for back surface grinding. The front surface is then chemical polished as a mirror surface which satisfies the requirement of a later photolithography step. Moreover, a deformation layer formed on the back surface of the semiconductor wafer is partially etched and left to provide an extrinsic gettering function. An epitaxial layer can be formed on the front surface to make the wafer an epitaxial wafer. The method of the present invention requires fewer process steps as compared with conventional methods, thereby reducing manufacturing time and cost.
    Type: Grant
    Filed: December 11, 1996
    Date of Patent: December 22, 1998
    Assignee: Komatsu Electronic Metals Co., Ltd.
    Inventors: Atsuo Nakazawa, Yuuichirou Mukai, Tomoaki Tajiri