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Browse Prior Art Database

Process for Reducing Gold or Copper Wafer Contamination During Oxide Removal

IP.com Disclosure Number: IPCOM000087112D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+2]

Abstract

A batch etching system using HF/H(2)O vapor mixtures is used for initial oxide removal of wafers. The system does not cause any contamination problems on the surface of the silicon wafers because oxide removal takes place in the presence of HF/H(2)O vapor mixtures, which do not contain any impurities such as gold, copper, etc.

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Process for Reducing Gold or Copper Wafer Contamination During Oxide Removal

A batch etching system using HF/H(2)O vapor mixtures is used for initial oxide removal of wafers. The system does not cause any contamination problems on the surface of the silicon wafers because oxide removal takes place in the presence of HF/H(2)O vapor mixtures, which do not contain any impurities such as gold, copper, etc.

When the gold or copper concentration of thermal oxide is greater than 10/11/ at/cc., the oxidized wafers are dipped into conventional buffered HF in order to remove the top part of the oxide layer prior to gas-phase etching.

In one example, about 1000 Angstroms of the oxide layer are removed by dipping the oxidized wafers into aqueous buffered HF-etch. After rinsing with DI-water and drying, the remaining oxide is removed by exposing the wafers for about five minutes to the HF/H(2)O vapor mixture.

To this end the wafers are placed under a TEFLON* bell jar about two inches above a 50% aqueous HF solution. The SiF(4) obtained during the reaction directly moves into the gas phase. After gas-phase etching, the wafers are dried in a hot nitrogen flow in order to avoid eventual contamination caused by a DI- water rinse. * Trademark of E. I. du Pont de Nemours & Co.

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