Method of making a rim-type phase-shift mask

US5484672A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Stanislav P. Bajuk · Colchester, US
• David S. O'Grady · Jericho, US
• Edward T. Smith · Somerville, US

Key dates

• Filing date: Jan 25, 1995
• Grant date: Jan 16, 1996
• Expiry date: Jan 25, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/0275
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method of forming rim type phase-shift lithography mask (140) involving backside overexposure of a positive resist layer (130) overlying a patterned light-blocking layer (120). By subjecting the resist layer to electromagnetic radiation (132) (e.g., broad band UV) transmitted via the backside (115) of the mask substrate (112), portions (134) of the resist layer extending from peripheral edges of the light blocking layer inwardly a selected distance are activated. After developing activated portions of the resist layer, the "pull back" of the resist layer is transferred to the underlying light blocking layer by anisotropically etching portions of the light blocking layer not covered by the resist layer, thereby forming the desired rim structure.