Fabrication of very fine copper lines on silicon substrates patterned with poly(methylmethacrylate) via selective chemical vapor deposition

This Brief Report follows a previous paper [Davazoglou et al., J. Vac. Sci. Technol. B 19, 759 (2001)] in which the selective chemical vapor deposition (SCVD) of Cu on W-covered Si substrates patterned with AZ 5214™ photoresist was demonstrated. Cu was then deposited by decomposition at temperatures between 110 and 140 °C from 1, 5 cyclooctadiene Cu (I) hexafluoracetylacetonate (COD-Cu-hfac) vapors. It was also shown that features with characteristic dimensions down to 0.5 μm are achievable with conventional optical lithography and SCVD of Cu. Moreover, it was shown that the process was reproducible and robust because sometimes Cu SCVD took place several weeks after tungsten deposition and AZ5214™ patterning. Following this work, we targeted a further decrease of the characteristic dimensions of the obtained features by SCVD from COD-Cu-hfac decomposition. We used, for the patterning, electron-beam lithography instead of optical lithography, and a well-known electron-beam resist.