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Selective Reactive Ion Etch for Silicon Oxide Over Silicon Nitride

IP.com Disclosure Number: IPCOM000037679D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Breiten, CP: AUTHOR [+3]

Abstract

This article presents a specific set of reactive ion etch (RIE) process parameters which provide a high etch rate ratio of silicon oxide to silicon nitride in a batch hexode system. The process uses well-known gases, such as CF4 and CHF3 to achieve high etch rate anisotropy and uniform etching, both within a wafer and from wafer to wafer.

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Selective Reactive Ion Etch for Silicon Oxide Over Silicon Nitride

This article presents a specific set of reactive ion etch (RIE) process parameters which provide a high etch rate ratio of silicon oxide to silicon nitride in a batch hexode system. The process uses well-known gases, such as CF4 and CHF3 to achieve high etch rate anisotropy and uniform etching, both within a wafer and from wafer to wafer.

The following etch conditions, when used in a batch hexode system, result in a seven-to-one etch rate ratio of silicon oxide to silicon nitride, with an etch uniformity of six percent for both films. RIE conditions: etch gas, CF4/CHF3 =
83.6% pressure = 55mtorr power = 1000 Watts DCbias = 425 Volts etch rates: SiO2 etch rate = 270 angstroms/minute Si3N4 etch rate = 40 angstroms/ minute. This process is advantageous in that it allows silicon nitride to be used as an etch barrier without the use of esoteric and possibly hazardous etch gases as is used in other processes. Both anisotropic etch and uniform etches can be achieved through the process and has been reduced to practice.

Disclosed anonymously.

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