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:
Mar. 07, 1989
Filed:
Jan. 11, 1988
Konrad Hieber, Bernau, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
The method for monitoring an end point of an etching process of electrically insulating layers effected by ions, radicals and/or neutral particles in a plasma is accomplished with the assistance of a reference substrate having a defined specimen geometry which is situated on a mobile substrate holder with the layers to be etched. The electrical resistance is measured and a voltage drop of a known constant current is impressed at known time intervals onto an electrically conductive layer lying under the layer to be etched. Measurement of the voltage drop is continued until an injection current is additionally injected into the conductive layer by the plasma to change the voltage drop. Test data is transmitted in non-contacting fashion by pulse code modulated electromagnetic radiation using a telemetry system so that the movable substrate is an independent unit. A process control computer controls the etching process via the etching rate by local monitoring of the end point of the etching carried out in the plasma.