Set of masks including a first mask and a second trimming mask with a semitransparent region having a transparency between 20% and 80% to control diffraction effects and obtain maximum depth of focus for the projection of structure patterns onto a semiconductor wafer

US7393614B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Roderick Köhle · Munich, DE
• Rainer Pforr · Dresden, DE
• Jorg Thiele · Birkenfeld, DE
• Wolfgang Dettmann · Schliersee, DE
• Markus Hofsäss · Hersbruck, DE
• Mario Hennig · Dresden, DE

Key dates

• Filing date: Mar 5, 2004
• Grant date: Jul 1, 2008
• Expiry date: Mar 12, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F1/70
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A set of at least two masks for the projection of structure patterns coordinated with one another by a projection system into the same photosensitive layer of a semiconductor wafer, in which the set of at least two masks includes a primary mask having an opaque structure element, which is formed at a first position on the first mask. A second mask of the set, for example a trimming mask, which is assigned to the first mask, can have a semitransparent region assigned to the structure element of the first mask. The semitransparent region can be formed at the same position on the second mask as the opaque structure element on the first mask. With the aid of the suitable choice of the transparency of the semitransparent region, it is possible to enable an undesirable resist region to be trimmed away for enlargement of a process window during exposure of the photosensitive layer on the semiconductor wafer.