Design and development of plasma enhanced chemical vapor deposition universal antireflective layer films for deep subquarter micron deep ultraviolet applications

A dual-layer, oxynitride film stack functions as a universal antireflective layer (UARL) for patterning deep subquarter micron features on transparent dielectric films. The UARL optical constants at 248 nm are n = 1.96 and k = 0.3 for top layer and n = 2.24 and k = 1.04 for bottom layer with film th ickness 360 and 650 Angstrom, respectively. The bottom UARL layer absorbs m ost of the incoming light, minimizing the light reflected from the underlyi ng substrate. Therefore, the reflectance back into the photoresist is a few tenths of one percent and is independent of the substrate material's optic al properties and structures. Results of patterning 0.18 mum photoresist li nes with the UARL on various Damascene film stacks show very tight critical dimension control. (C) 2000 American Vacuum Society. [S0734-211X(00)04606- 0].