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Low Temperature Plasma Conversion of Silicon Nitride to Silicon Dioxide

IP.com Disclosure Number: IPCOM000087305D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bhattacharyya, A: AUTHOR [+3]

Abstract

The desirability of the use of silicon nitride as a passivation and masking material in semiconductor processing is offset by its trapping characteristics and the fact that it induces stresses in underlying semiconductor substrates. It is, therefore, advantageous to develop a low-temperature nonaqueous process to provide for the removal or elimination of silicon nitride to avoid the undesirable characteristics. This method provides an effective technique for converting silicon nitride to silicon dioxide by low-temperature gaseous plasma.

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Low Temperature Plasma Conversion of Silicon Nitride to Silicon Dioxide

The desirability of the use of silicon nitride as a passivation and masking material in semiconductor processing is offset by its trapping characteristics and the fact that it induces stresses in underlying semiconductor substrates. It is, therefore, advantageous to develop a low-temperature nonaqueous process to provide for the removal or elimination of silicon nitride to avoid the undesirable characteristics. This method provides an effective technique for converting silicon nitride to silicon dioxide by low-temperature gaseous plasma.

Semiconductor wafers having exposed nitride, with or without underlying other material layers, are placed in a plasma reactor on a pedestal designed to act as an electrical anode and/or to act as a heat sink. A high frequency, greater than 100 KHz, and low energy, less than 1,000 watts, generator is used to create an oxygen plasma of appropriate composition. The high frequency generator may be coupled to the reactor by an RF, capacitive or microwave cavity. The plasma may also be created by a pulsed DC generator. The oxygen plasma creates 0/-/ ions which readily react with silicon nitride to form silicon dioxide and nitrogen gas. The nitride is converted layer by layer at temperatures of from 200 to 800 Degrees C. Once full conversion is established, further exposure will promote additional oxidation of the underlaying substrate, usually silicon. After conver...