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Reactive Ion Etch Process for Etched Sidewall Tailoring

IP.com Disclosure Number: IPCOM000088031D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Clark, HA: AUTHOR

Abstract

A reactive ion-etch process for quartz is carried out in a manner which uses controlled photoresist mask degradation to produce an etched quartz profile with a rounded edge. The profile provides for better evaporated metal coverage and avoids device yield/reliability problems.

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Reactive Ion Etch Process for Etched Sidewall Tailoring

A reactive ion-etch process for quartz is carried out in a manner which uses controlled photoresist mask degradation to produce an etched quartz profile with a rounded edge. The profile provides for better evaporated metal coverage and avoids device yield/reliability problems.

A wafer to be etched, whose 2.2 mu thick surface quartz layer is partially protected by a patterned resist layer to permit the etching of via holes, is placed on a quartz backing plate in a plasma etcher. The quartz backing plate protects the backside of the wafer from the reactive plasma and acts as a heat sink to control the wafer and resist temperature during the etching process. A perforated metal cylinder is placed in the etch chamber to assure uniform etching of each device site on the wafer. A reactive etchant gas of CF(4) and approximately 17% oxygen is used with 400 watts power.

During the etching of the first 8,000 to 10,000 angstroms of quartz, the quartz plate and metal cylinder keep the resist temperature down so that only about 2,000 angstroms of resist is lost. While etching the remaining quartz, full wafer temperature is reached and lateral removal of resist occurs to expose fresh quartz around the openings. This results in a round rather than a sharp edge at the top of the opening in the quartz layer. This rounded edge 1, is easily covered by a subsequently applied metal layer, as shown in the figure.

When etching thin...