No abstract

Extraction of small molecule components into water from photoresist materials designed for 193 nm immersion lithography has been observed. Leaching of photoacid generator (PAG) has been monitored using three techniques:  liquid scintillation counting (LSC); liquid chromatography mass spectrometry (LCMS); and scanning electrochemical microscopy (SECM). LSC was also used to detect leaching of residual casting solvent (RCS) and base. The amount of PAG leaching from the resist films, 30−50 ng/cm2, was quantified using LSC. Both LSC and LCMS results suggest that PAG and photoacid leach from the film only upon initial contact with water (within 10 s) and minimal leaching occurs thereafter for immersion times up to 30 min. Exposed films show an increase in the amount of photoacid anion leaching by upward of 20% relative to unexposed films. Films pre-rinsed with water for 30 s showed no further PAG leaching as determined by LSC. No statistically significant amount of residual casting solvent was extracted after 30 min of immersion. Base extraction was quantified at 2 ng/cm2 after 30 s. The leaching process is qualitatively described by a model based on the inhomogeneities in resist films.

Abstract.A robust quantitative structure property relationship ͑QSPR͒ model with five parameters has been developed from 126 organic compounds for the prediction of refractive index at 589 nm. The model and the knowledge of the refractive index dispersion were used in the rational design of new materials for 193-nm immersion lithography. The significance of this model is that the structural descriptors can be readily calculated and the factors that significantly affect refractive index can be easily identified and used to guide the selection of candidates. Using this model, rapid screening of large structure databases is possible in order to find candidates. As an example of this approach, the synthesis of the copolymer of a trithiocyclane-methacrylate derivative, identified by the model, with 2-methyl adamantyl methacrylate is described. The measured refractive index of the copolymer at 589 nm agrees well with the value predicted by the model. The new polymer showed a 9.4% increase in refractive index at 193 nm compared with the standard ArF resist.

The synthesis and characterization of several new fluoropolymers designed for use in the formulation of photoresists for exposure at 157 run will be described. The design of these resist platforms is based on learning from previously reported fluorine-containing materialsl. We have continued to explore anionic polymerizations, free radical polymerizations, metal-catalyzed addition polymerizations and metal-catalyzed copolymerizations with carbon monoxide in these studies. A new, three component design for 157nm resists will alos be presented. The monomers were characterized by vacuum-UV (VUV) spectrometry and polymers characterized by variable angle spectroscopic ellipsometry (VASE). Resist formulations based on these polymers were exposed at the 157 nm wavelength to produce high-resolution images. The synthesis and structures of these new materials and the details of their processing will be presented.

No abstract