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:
Dec. 07, 1993
Filed:
Jan. 22, 1992
Tetsuji Nagayama, Kanagawa, JP;
Shingo Kadomura, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A dry etching method for silicon trench etching in which high anisotropy, high etchrate and low pollution may be achieved simultaneously. A single crystal silicon substrate is etched using a gas mixture of S.sub.2 Cl.sub.2 and S.sub.2 F.sub.2 while a wafer is cooled to about -70.degree. C. Etching proceeds by a mechanism in which a radical reaction by Cl* derived from S.sub.2 Cl.sub.2 and F* derived from S.sub.2 F.sub.2 is assisted by the incident energy of S.sup.+, SF.sup.+, SCl.sup.+ or Cl.sup.+ ions. The highly reactive F* radicals of a small atomic radius contribute to increasing the etchrate. Deposition of sulfur yielded from S.sub.2 Cl.sub.2 and S.sub.2 F.sub.2 provides for efficient sidewall protection to achieve high anisotropy. The conventional practice to add fluorine based gases with a view to increasing the etchrate is in need of an excess quantity of a deposition material to give rise to increased pollution by particles. There is no risk of pollution with the sulfur deposit according to the present invention because the sulfur deposit may easily be sublimed off by heating the wafer.