Materials evaluation of antireflective coatings for single-layer 193-nm lithography

A survey of optical constants for a variety of materials measured at 193 nm suggests that antireflection measures will be necessary for single-layer resist lithography at 193 nm. The extent to which standing waves occur in 193-nm resists is similar in magnitude to those occurring at 248 nm. To help reduce these effects, a new spin-on antireflective layer has been developed. It is composed of a polymeric dye in a phase-compatible blend with a transparent base polymer, can be thermally cured to render it insoluble, and is compatible with chemically amplified resists. In addition to this spin-on material, extension of existing 248-nm dry-deposited antireflective layers to 193 nm should allow for either spin-on or dry-deposited antireflection coatings for 193-nm lithography.