Helen S Maynard

US Patent:

20020029853, Mar 14, 2002

Filed:

May 30, 2001

Appl. No.:

09/870968

Inventors:

Eric Hudson - Berkeley CA, US
Jaroslaw Winniczek - Daly City CA, US
Joel Cook - Pleasanton CA, US
Helen Maynard - New York NY, US

International Classification:

H01L021/3065

US Classification:

156/345000

Abstract:

Disclosed are methods and systems for etching dielectric layers in a high density plasma etcher. A method includes providing a wafer having a photoresist mask over a dielectric layer in order to define at least one contact via hole or open area that is electrically interconnected down to the silicon substrate of the wafer. The method then proceeds to inserting the wafer into the high density plasma etcher and pulsed application a TCP power source of the high density plasma etcher. The pulsed application includes ascertaining a desired etch performance characteristic, which includes photoresist selectivity and etch rate which is associated with a continuous wave application of the TCP source. Then, selecting a duty cycle of the pulsed application of the TCP source and scaling a peak power of the pulsed application of the TCP source in order to match a cycle-averaged power that would be delivered by the continuous wave application of the TCP source. The pulsed application of the TCP power source is configured to etch through the dielectric layer to at least one contact via hole or open area while substantially reducing damage to the transistor gate oxides of the transistor devices.

US Patent:

62282778, May 8, 2001

Filed:

Oct 14, 1998

Appl. No.:

9/172456

Inventors:

Avinoam Kornblit - Highland Park NJ
Heon Lee - Fishkill NY
Helen Louise Maynard - Menlo Park CA

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H01L 2166
G01R 3126

US Classification:

216 60

Abstract:

The specification describes an interferometric in-situ end point detection technique for plasma etching in which the end point is predicted before any overetching occurs. It is based on the recognition that the wavelength of the monitoring beam can be selected so that only a single interferometric fringe appears before clearing. Knowing there is only one fringe, detection is simplified and the etching process can be terminated while a finite but small thickness of the layer remains. This allows etching partial thicknesses of layers. It also allows a two step etch process wherein the etch chemistry can be changed to a highly selective etch to complete clearing of the layer.