Method for the selective removal of silicon dioxide

US5662772A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Thomas Scheiter · Munich, DE
• Ulrich Naeher · Munich, DE
• Christofer Hierold · Munich, DE

Key dates

• Filing date: Apr 24, 1996
• Grant date: Sep 2, 1997
• Expiry date: Apr 24, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/935
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

In a method for the selective removal of SiO.sub.2 relative to semiconductor materials and/or metal, a specimen to be processed and containing SiO.sub.2 is placed into a chamber having at least one gas admission opening and one gas outlet opening. Using controllable valves at the gas admission opening, dosed quantities of hydrogen fluoride gas and water vapor are admitted into the chamber. These gasses proceed to the SiO.sub.2 in a specimen in a quantity adequate for etching. However, the quantities of these gasses are limited such that a condensation of the water vapor to form liquid water on the specimen during the etching event is avoided. An etching event is then implemented. Water vapor that arises as a reaction product during the etching is eliminated through the gas outlet opening before the occurrence of condensation and, simultaneously, an inert gas is admitted into the chamber through the gas admission opening. These steps are repeated as needed.