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:
Jun. 02, 2020
Filed:
Mar. 24, 2017
Hitachi Metals, Ltd., Minato-ku, Tokyo, JP;
Hisayuki Imamura, Tokyo, JP;
Suguru Fujita, Tokyo, JP;
Youichirou Kaga, Tokyo, JP;
Hiroyuki Teshima, Tokyo, JP;
Shigeyuki Hamayoshi, Tokyo, JP;
HITACHI METALS, LTD., Tokyo, JP;
Abstract
Provided is a large-sized silicon nitride sintered substrate and a method for producing the same. The silicon nitride sintered substrate has a main surfaceof a shape larger than a square having a side of a length of 120 mm. A ratio dc/de of the density dc of the central area and the density de of the end area of the main surfaceis 0.98 or higher. The void fraction vc of the central area of the main surfaceis 1.80% or lower, and the void fraction ve of the end area is 1.00% or lower. It is preferred that the density dc of the central area is 3.120 g/cmor higher, the density de of the end area is 3.160 g/cmor higher, and a ratio ve/vc of the void fraction vc of the central area and the void fraction ve of the end area is 0.50 or higher.