248-nm DUV MoSiON embedded phase-shifting mask for 0.25 micrometer lithography

Over the past five years worldwide efforts have been made to develop new techniques for optical lithography enhancement. These techniques include optical proximity correction, off-axis illumination, pupil filtering and phase-shifting mask (PSM). Among many phase-shifting mask approaches, embedded PSM (EPSM) method has drawn significant interest due to its relatively simple reticle fabrication process and excellent lithographic performance, in particular, for dark field mask layers such as contact and via holes. Perhaps, the most difficult task in materializing the EPSM technology is the creation of a thin film structure that controls both phase and transmission. In addition, this film structure must withstand severe environment of mask making process and yet can be inspected and repaired successfully using currently available tool sets. The newly developed MoSiON material meets these requirements and has demonstrated a feasibility for DUV EPSM pilot production. In this paper, characteristics of the DUV lifetime test results. Details of reticle fabrication process including e-beam writing, dry etching, inspection and repair will be presented along with chemical durability data and process capability. Finally, wafer level lithographic performance for contact holes printed on a step-and-scan and a projection aligner will be shown to demonstrate lithographic performance of 248 nm DUV EPSM for 0.25 micrometer lithography.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.