0.12 μm optical lithography performances using an alternating DUV phase shift mask

Abstract

Manufacturing the next generation of devices will demand lithographic capability in the sub 0.18 μm range. The phase shift mask (PSM) is a key emerging technology thought to be extending 248 nm optical lithography. Using the Levenson PSM technique allows us to improve resolution by as much as 50% at gate level. This paper describes the lithographic performances of Shipley UV5 photoresist on SiOxNy BARC, using alternating PSM and an ASM/90 Deep UV stepper. CD measurement was done on OPAL 7830i metrology SEM. Results on sub 0.18 μm design rules are presented: • - The first part concerns experimental conditions: masks, process conditions, anti-reflective substrates, etching and metrology are discussed. • - The second part concerns lithographic performances: process linearity from 0.12 μm to 0.18 μm, 0.12 μm isolated line process latitudes of 7% Energy Latitude for 0.8 μm DOF have been exhibited. Finally we try to evaluate proximity effect and the ultimate resolution of this technology.