Exposing a semiconductor wafer using two different spectral wavelengths and adjusting for chromatic aberration

US7286207B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Christoph Nolscher · Dresden, DE
• Andreas Jahnke · Munich, DE

Key dates

• Filing date: Apr 28, 2005
• Grant date: Oct 23, 2007
• Expiry date: Jul 15, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70333
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A semiconductor wafer is exposed with a pattern from a mask or reticle in an exposure tool. The exposure tool has an adjustable lens system and a light source, which is tunable in wavelength. A first exposure is performed with a tuned first wavelength and a first setting of the lenses. Prior to performing a second exposure onto the same wafer and into the same resist layer, the wavelength of the light source is varied to a second wavelength in order to mimic a focus offset. A resulting image shift at the slit edges of the scanning system due to chromatic aberration is then corrected for by setting the lens system in dependence of the difference between the tuned first and second wavelength. Having tuned second wavelength of the light source and having set the lens system, the second exposure is performed. A continuous adjustment of the lens system based upon a continuously varying light source wavelength can be accomplished.