Method of reducing pitch on semiconductor wafer

US6842222B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Gerhard Kunkel · Radebeul, DE
• Shahid Butt · Ossining, US
• Alan C. Thomas · Gilbert, US
• Juergen Preuninger · Munich, DE

Key dates

• Filing date: Apr 4, 2003
• Grant date: Jan 11, 2005
• Expiry date: Apr 4, 2023

Classification

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

Abstract

A projected image is formed during a material substrate. A photolithographic mask is illuminated with substantially coherent light at an oblique angle of incidence with respect to a surface of the photolithographic mask. The photolithographic mask includes a substantially transparent mask substrate and one or more lines and spaces patterns formed on the mask substrate and having a periodicity P. The mask substrate includes at least one phase shifting region. At least part of the light that is transmitted through the photolithographic mask is collected using one or more projection lenses which project the portion of the transmitted light onto the material substrate. The material substrate is disposed substantially parallel with, but at a distance from, a focal plane of the projection lens system. The phase shifting region of the mask substrate and the distance from the focal plane are selected such that a substantially focused image is projected onto the material substrate that includes the lines and spaces patterned but with a periodicity P/2.