Performances of Triple-tone Contact Hole Mask for Optical Lithography Extensions

摘要

In this paper we suggest a promising strategy for optical lithography extension. In general the process margin of a contact hole is poorer than line and space patterning for the same feature size. An asymmetrical contact hole mask designed by simulations was fabricated and printed, Several techniques in designing this photomask have been considered. We have some difficulties in patterning device with design rule of below sub-half micrometer. And we have to overcome not only wafer pattern fidelity but also mask manufacturing process such as OPC pattern generation and defect inspection and repair. Attenuated triple-tone phase shifting masks with higher transmission and patterned opaque regions give better imaging performances with improved process margins. Therefore we suggest that a triple-tone mask is a possible solution for the optical lithography extension technology.