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:
Apr. 14, 2009
Filed:
Oct. 06, 2005
Ralf Lerner, Erfurt, DE;
Uwe Eckoldt, Hohenfelden, DE;
Ralf Lerner, Erfurt, DE;
Uwe Eckoldt, Hohenfelden, DE;
X-FAB Semiconductor Foundries AG, Erfurt, DE;
Abstract
An efficient method for the thermal oxidation of preferably silicon semiconductor wafers using LOCOS (local oxidation of silicon) processes is described. The mechanical stresses of the wafers are to be reduced. To this end, an oxidation method is proposed that comprises providing a substrate () having a front side () to be patterned and a rear side (). The substrate is oxidized in two steps. In a first step the rear side () is covered by a layer () that inhibits or hampers the oxidation. During a second step of the oxidation the oxidation-hampering layer () is no longer present. During both steps an oxide thickness is obtained on the front side () that is greater than an oxide thickness obtained on the rear side ().