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Browse Prior Art Database

Plasma Etching Process

IP.com Disclosure Number: IPCOM000082456D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Clark, HA: AUTHOR

Abstract

Plasma etching of materials, such as silicon or silicon oxide, using a resist mask is carried out in a series of steps separated by delay or cooling off periods rather than continuously, to improve the uniformity of etch and to reduce attack on the resist mask.

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Plasma Etching Process

Plasma etching of materials, such as silicon or silicon oxide, using a resist mask is carried out in a series of steps separated by delay or cooling off periods rather than continuously, to improve the uniformity of etch and to reduce attack on the resist mask.

An epitaxial layer of silicon is uniformly and smoothly etched without pitting the surface, by employing a RF plasma of a mixture of an organo halide and oxygen. The etching is carried out in several etch increments with a delay or RF interrupt between each etch increment. The delay is achieved by interrupting the screen-grid potential to cut off RF power, while maintaining the gas flow and other system parameters constant.

Thick silicon dioxide layers of 5000 Angstroms and greater thickness are coated with a pattern of photoresist and etched, without destruction of the protective photoresist layer. The type of resist being used, the oxide thickness and etch parameters determine the timing and duration of the etch and RF interrupt increments. For example, one to two minute etch periods with interrupt periods of sufficient duration to permit cooling are found to avoid excessive loss of resist, even where less resistant resists are employed. The etch periods are repeated until the desired depth of etch has been achieved. The process also allows a higher oxygen content to be used which permits the tailoring of selective etch rates.

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