Dry Deposition and Dry Development of Metal Oxide Based Photoresist

Herein, we present high-resolution EUV patterning results achieved using Lam Research's negative-tone metal-oxide-based photoresist. We enable an entirely dry resist process flow by employing both the deposition and the development in the vapor phase. This approach offers benefits over conventional spin coating and wet development methods. It eliminates the need for organic solvents used for both coating and development steps, as well as the line-collapse defects which stem from the capillary forces during desolvation of wet developers. Additionally, by employing a vapor phase developer that reacts, volatilizes, and sequentially removes one monomeric species at a time from the wafer, superior resolution and wider process windows can be attained. In this report, we describe the dry development chemistries which selectively react and remove unexposed regions of the material, as well as the key parameters which influence the etch rates and selectivity. Using our dry process we demonstrate line/space patterns resolved at 24nm pitch with patterning metrics targeted toward high NA EUV lithography.