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:
Sep. 03, 1996
Filed:
Aug. 19, 1994
Nippondenso Co., Ltd., Kariya, JP;
Abstract
An LOCOS film is formed on an Si substrate, a gate oxide film and a gate electrode are formed thereon, and source/drain impurities are ion implanted into the Si substrate using the gate electrode as a mask. Then, a BPSG film is formed at a film density of 1.8 g/cm.sup.3 or more. A recessed part is formed in the BPSG film by the first photolithographic process with an etching depth of 20% or more but under 100% of the thickness of the BPSG film. Thereafter, the BPSG film is fluidized by reflow treatment to shape a part which is to be a contact hole into a funnel with an 'upwards convex' curvature. Finally, the part formed into the funnel is etched to make a contact hole. As a result, wiring disconnection within the contact hole can be prevented, the diffusion depth controllability for the source/drain impurities can be improved, and the fall in the impurity density in the source/drain surface can be prevented.