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, 1992
Filed:
Dec. 31, 1990
Applicant:
Inventor:
Manfred Engelhardt, Feldkirchen-Westerham, DE;
Assignee:
Siemens Aktiengesellschaft, Munich, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
156643 ; 156647 ; 156662 ; 437 52 ; 437 67 ;
Abstract
A method is provided for producing trench structures having vertical, smooth side walls and straight, flat trench floors in silicon substrates. The reactive ion etching is implemented in a triode single-wafer plate reactor upon use of an etching mask preferably composed of SiO.sub.2, and with an etching gas atmosphere exclusively composed of chlorine, being implemented at a low-pressure. Compared to known ion etching processes, the method provides acceptable etching rates with a carbon-free, simple etching chemistry. The method is particularly useful for producing DRAMs with cell concepts of more than 4 Mbits.