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. 13, 2004
Filed:
Dec. 28, 2000
Franz Laermer, Stuttgart, DE;
Andrea Schilp, Schwaebisch Gmuend, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
A method of anisotropic etching of structures in a semiconductor body, in particular of recesses in a silicon body ( ) exactly defined laterally by an etching mask, by using a plasma ( ) is proposed. An ion acceleration voltage induced in particular by a high-frequency AC voltage is applied to the semiconductor body at least during an etching step having a predefined duration. The duration of the etching step is further subdivided into at least two etching segments between which the ion acceleration voltage applied is modified each time. Preferably two etching segments are provided, a higher acceleration voltage being used during the first etching segment than during the second etching step. The length of the first etching segment can furthermore be determined dynamically or statically during the etching steps using a device for the detection of a polymer breakdown. In order to generate and adjust the value of the acceleration voltage, preferably high-frequency pulses or pulse packets having an adjustable pulse/pause ratio are used.