A Novel Resist Freeze Process for Double Imaging

In this study we explore a novel resist freeze process for dual imaging with broad resist and lithography track compatibility. The Vapor Reaction Chamber (VRC) hardware is similar to a HMDS prime chamber. Freeze liquids are selected based on their ability to freeze a positive resist image, and among the materials tested, low boiling point diamines were found to be the most effective. Temperature, freeze material, gas flow rate and time are varied to adjust the process and investigate the impact on dual image profiles. Rapid freezing of the 1st photoresist image is achieved when the VRC temperature is near the Tg of the photoresist polymer, and process times are compatible with track wafer flows. The process has been used to create dual imaging features with dry lithography to achieve 45 nm dense L/S patterns.