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:
Oct. 31, 2006
Filed:
Mar. 29, 2004
Thomas N. Adam, Poughkeepsie, NY (US);
David C. Ahlgren, Wappingers Falls, NY (US);
Kangguo Cheng, Beacon, NY (US);
Ramachandra Divakaruni, Ossining, NY (US);
Thomas N. Adam, Poughkeepsie, NY (US);
David C. Ahlgren, Wappingers Falls, NY (US);
Kangguo Cheng, Beacon, NY (US);
Ramachandra Divakaruni, Ossining, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of forming a trench in a semiconductor substrate includes a step of converting the cross section of the upper portion of the trench from octagonal to rectangular, so that sensitivity to alignment errors between the trench lithography and the active area lithography is reduced. Applications include a vertical transistor that becomes insensitive to misalignment between the trench and the litho for the active area, in particular a DRAM cell with a vertical transistor.