The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 24, 2011
Filed:
Mar. 03, 2009
Applicants:
Youichirou Kaga, Kitakyushu, JP;
Junichi Watanabe, Kumagaya, JP;
Inventors:
Youichirou Kaga, Kitakyushu, JP;
Junichi Watanabe, Kumagaya, JP;
Assignee:
Hitachi Metals, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 23/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A silicon nitride substrate having appropriately adjusted warpage and surface roughness can be obtained by mixing magnesium oxide of 3 to 4 wt % and at least one kind of rare-earth element oxide of 2 to 5 wt % with silicon nitride source material powder to form a sheet-molded body, sintering the sheet-molded body, and performing a heat treatment at a temperature of 1,550 to 1,700 degree C. with a pressure of 0.5 to 6.0 kPa with a plurality of substrates being stacked. Also, a silicon nitride circuit board and a semiconductor module using the same are provided.