A new method was developed to study the diffusion of photogenerated acid in chemical amplification resist systems which allowed an estimation of the diffusion range by simple means. The acid mobility was investigated for two different resist systems under various process conditions. It was found that solvent traces in the film cause a very strong increase of the acid mobility. In order to control the diffusion range, the post-exposure-bake temperature must be below the glass transition temperature. For one resist system, the increase in resist sensitivity with increasing baking temperature was much smaller than the corresponding increase in diffusion range. The results corresponded well with those obtained by lithography with the same resist.

A new simple method was developed to estimate the diffusion range of photogenerated acid in chemical amplification resist systems. The acid mobility was investigated for various process conditions. It was found that prebake and post-exposure-bake conditions have strong influence on the mobility of acid. The diffusion range of acid is much larger than values estimated from the catalytic volume. No acid diffusion could be detected at room temperature over a period of 2 days. Acid from an opium salt acid generator showed a stronger diffusion than acid from a methanesulfonic acid ester.

A novel water-soluble photoinitiator, sodium 4-[2-(4-morpholino)benzoyl-2-dimethylamino]-butylbenzenesulfonate (MBS), was synthesized by sulfonation of 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (BDMB) for "environmentally friendly" and "completely water-soluble" resist systems. MBS showed sufficient solubility in water and the same high sensitivity as BDMB. Novel water-soluble photopolymerization resist systems, composed of MBS, polyfunctional acrylate monomers, and water-soluble polymers, were also evaluated. Among the commercially available polyfunctional acrylate monomers, a trifunctional epoxy acrylate monomer from glycerol (DA-314) showed good solubility in water. The sensitivity of this resist system to irradiation of 365-nm UV light was 1.5 mJ/cm 2 at 2-µm film thickness. Advantages of the resist are no need for any organic solvent or any alkaline developer. The chemistry of MBS was investigated by IR and photolysis. It was proved that the radical generation mechanism of MBS was the same as for BDMB.

A simple and accurate means of reproducing the band structure of an FCC transition metal is by means of a model Hamiltonian which depends on a set of parameters determined from known energy eigenvalues at symmetry points in the Brillouin zone. It is shown that the model Hamiltonian can also reproduce the metal charge density with good accuracy if care is taken with the choice of atomic orbitals to be used in the calculations.Calculations are performed for Ni. Cu, Rh, Pd and Ag and the spherically averaged charge densities obtained from the model Hamiltonian are compared with those of Moruzzi er al. Agreement to better than 10% is obtained in all cases out to the muffin-tin radius.

No abstract