Abstract
Developable bottom anti-reflective coatings (DBARCs) are useful for implant layers because they eliminate the plasma etch step avoiding damage to the plasma sensitive layers during implantation. It is expected that DBARC will also be used for non-implant layers and double exposure technology. AZ has pioneered DBARCs based on photosensitive cleave as well as crosslink/decrosslink mechanisms.
In this paper, we focus on the challenges and advances in the photosensitive DBARCs, including DBARC/resist matching and the influence of various process factors on lithographic performance, such as prewet, thickness, topography and substrates. DBARC/resist mismatching was addressed both from process and formulation sides. Prewet of DBARC before resist coating deteriorated performance, however, it was overcome by modifying DBARC formulations. The optimized DBARC showed both optical and lithographic performance comparable to conventional BARCs. DBARCs minimized reflection from the substrates and notching of patterns was improved on silicon oxide topography. This paper includes simulation, DBARC contrast curve analyses, recent 248 nm, 193 nm dry and immersion exposure results of DBARC.
