Apparatus for assessing a silicon dioxide content

US6749716B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Stefan Ottow · Dresden, DE
• Ulf Steuer · Dresden, DE

Key dates

• Filing date: Oct 18, 2002
• Grant date: Jun 15, 2004
• Expiry date: Nov 11, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/67242
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

An apparatus for assessing a silicon dioxide content of a phosphoric acid bath for etching silicon nitride and a system for etching silicon nitride bath utilize a sensor. In particular, the apparatus for assessing the silicon dioxide content of a phosphoric acid bath for etching silicon nitride of the present invention contains a sensor for measuring the NH3 concentration of the phosphoric acid bath, a storage unit for storing data which define a relationship between the silicon dioxide content and the NH3 concentration, and a device for calculating the silicon dioxide content of the basis of the measured NH3 concentration and the stored data.