Post-exposure delay stability for 193 nm single-layer photoresist: Solventeffect

We investigated the effect of post-exposure delay (PED) for poly[2-(2-hydro xyethyl)carboxylate-5-norbornene-co-2-carboxylic acid-5-norborene-co-maleic anhydride] [poly(HNC/BNC/NC/MA)] resist film, which formulated with photoa cid generator (PAG) under the several solvents. The solvents used in this s tudy mere propylene glycol methyl ether acetate (PGMEA), isobutyl methyl ke tone (IBMK), 2-heptanone (2-H), and (alpha-methoxy)ethyl acetate (MEA). We have introduced a new concept of rheological approach to explain the solven t effect for PED by using rheometer and light scattering equipment. In the PGMEA solvent, the resist solution shows Newtonian behavior, but the other resist solutions show shear-thinning behavior. The resist film prepared by the shear-thinning solvent exhibited good FED stability. In order to explai n these results, we conjectured that the resist polymer existed in long-rod shape under the specific solvent and high shear rate. Also, we could obtai n 0.16 mu m L/S patterns in a severely amine-contaminated environment (abou t 35 ppb) after 30 min FED by using this method. (C) 2000 John Wiley & Sons , Inc.