The effect between absorber profile and wafer print process window in ArF 6% Att. PSM mask

Abstract

As the leading edge semiconductor technology development, the gate critical dimension (CD) shrinks below 90nm. The microlithography capability is limited by the exposure utility. The development of scanner is focusing on low k that is implying that the high NA scanner is the main stream in the future. In addition, the high NA reticle requirement is stricter than previous one. In aspect of mask manufacturing, reducing mask topography effect is one of the various solutions, which is like lower mask blank flatness, should be lower than 1T flatness type or else. Unless the mask flatness, the absorber profile also could be a considerate effect element, which is local topography effect contribution in wafer print window.The main purpose of this study is verifying how much wafer prints window discrepancy between different absorber profiles. The experiment pattern is designed for five kind of MoSi sidewall angle (SWA) on the same mask, which could simultaneously gathers the wafer print window data. In addition, the other purpose is getting exactly the same process condition of five kinds MoSi profile in both mask house and lithography of wafer manufacturing Fab. The mask layout pattern is poly layer of logical 90 nm generation that is more critical among all of lithography and was exposed by 193nm ArF.Then, we offer the effected level between absorber profile and lithography process window. The process window of different SWA pattern will be compare to check the relationship between process windows and mask profile. We also investigate how the profile affects the optical proximity behavior.Key word: mask, mask flatness, mask blank, process window, wafer print, sidewall angle (SWA), local 3D effect, global 3D effect.