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. 19, 1992
Filed:
May. 24, 1991
Thomas R Baker, Tempe, AZ (US);
Bernard W Boland, Phoenix, AZ (US);
David A Shumate, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A substantially planar dielectric wafer is formed by utilizing a polysilicon filler to remove surface irregularities (15, 15'). The polysilicon filler is formed by filling surface irregularities (15, 15') with polysilicon (19) and polishing the polysilicon (19) to form a substantially planar surface. A polishing stop (18) terminates the polishing and prevents damage to the wafer's isolated tubs (13). The polishing stop (18) can also be used as a mask during field oxide growth. The polysilicon filler also protects underlying areas (12) from subsequent etch operations. During subsequent field oxide growth, polysilicon layer (19) is converted to silicon dioxide which enhances dielectric isolation of each tub (13).