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We have examined four molecular glasses (MGs) which are candidates for EUV photoresist formulations. These
derivatized glasses, and their unprotected precursors, were investigated by both proton and 13C solid state NMR
techniques in the bulk state as pure materials and as mixtures with 5 or 10 % by mass of the photoacid generator (PAG),
triphenyl sulfonium perfluorobutanesulfonate. The 13C techniques gave information about crystallinity, purity, and the
presence of the PAG. This paper characterizes the intimacy of mixing of the PAG and the MGs using proton spin
diffusion methods. Phase separation of the PAG into PAG-rich larger domains was never seen; the PAG was always
finely distributed. A maximum diameter for any PAG clustered into spherical domains was estimated to be 3.8 nm,
which is too small to reflect thermodynamic incompatibility as the driving force during relatively slow removal of
solvent. Hence, PAG blended samples are deduced to be thermodynamically compatible, with differential solubility in
the preparation solvent the most likely candidate for producing the significant inhomogeneities in PAG concentration
observed in a few samples. For one of the unprotected crystalline calix[4]resorcinarenes precursor materials, the
solvent, N-methyl 2-pyrrolidinone (NMP) was used. The resulting solid was crystalline with a segregation of isomers,
one of which formed a solid adduct with a 1:1 molecular ratio with NMP. Qualitatively, the strong NMP affinity for the
calix[4]resorcinarenes is also evident in a) the immobility of the NMP, b) the fact that the 14N quadrupolar interaction
changes when NMP goes from the crystalline, unprotected host to a glassy, protected host, and c) that NMP tends to
remain as a significant residue. Only the underivatized materials display crystallinity implying that the mixing of the
PAG with any derivatized MG is not restricted by crystallization, at least not before the post-exposure bake step. As a
final note, very strong hydrogen bonds exist in three underivatized materials which is reduced or eliminated with partial
protection with t-BOC.
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