Direct patterning using metallo‐organics and its application to mask repair

Au patterns are formed by photographical patterning of polymeric Au mercaptoterpenes (Au resinate), followed by bakeout of the Au resinate patterns to remove carbonaceous materials. Since commercially available Au resinate is not sensitive to 436 nm (g‐line) light and cannot be photographically patterned, we mixed azide (photocrosslinker) with Au resinate to give photosensitivity to the g‐line. The mixture of Au resinate and azide was spun on an Si substrate, and then exposed with 436 nm (g‐line) light by a standard contact printing technique. Upon exposure, Au resinate was crosslinked by the reaction with azide, and became insoluble. Au resinate patterns were generated by development with monochlorobenzene. On baking out the Au resinate patterns to remove carbonaceous materials, we obtained 2 μm line and space Au patterns. The conductivity of the Au patterns obtained was 1/4 that of bulk Au. For a mask repair application, we mixed Cr resinate with a mixture of Au resinate and azide to improve the adhesion of the resulting metal patterns onto the quartz plate. The transmittance and the adhesion were found to depend on the bakeout condition and the mixing ratios of the Cr resinate. Bakeout in vacuum with 0.1 torr oxygen gave far better adhesion and opaqueness than bakeout in air, because of residual carbon in the resultant metal. Mask repair was carried out at the optimized condition by using a spot exposure system. The clear defect was repaired with the transmittance < 1% and good adhesion.