Trimming mask with semitransparent phase-shifting regions

US6466373B1 · kind B1 · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Rainer Pforr · Dresden, DE
• Christoph Friedrich · Hersbruck, DE
• Klaus Ergenzinger · Oberhaching, DE
• Fritz Gans · Hersbruck, DE
• Uwe Griesinger · Hersbruck, DE
• Wilhelm Maurer · Hopewell Junction, US
• Jurgen Knobloch · Ruderatshofen, DE

Key dates

• Filing date: Sep 29, 2000
• Grant date: Oct 15, 2002
• Expiry date: Oct 9, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/2026
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

For lithographically producing the smallest structures at less than the exposure wavelengths in semiconductor fabrication, a double exposure is carried out using a thick phase mask and a trimming mask, the trimming mask further structures the phase-contrast lines produced by the phase mask. Besides transparent or opaque regions, the trimming mask also has phase-shifting regions. These surround transparent regions of the trimming mask through which the phase-contrast lines produced by the first mask are locally re-exposed, that is to say interrupted. The intensity profile of successive line sections is especially rich in contrast through the addition of the phase-shifting partially transparent regions on the second mask; the distances between the line sections can be reduced. The trimming mask, otherwise used only for larger structures, is therefore suitable for the configuration of the finest dimensionally critical structures.