RESUMEN
This study suggests a Ru/ZnO bilayer grown using area-selective atomic layer deposition (AS-ALD) as a multifunctional layer for advanced Cu metallization. As a diffusion barrier and glue layer, ZnO is selectively grown on SiO2 , excluding Cu, where Ru, as a liner and seed layer, is grown on both surfaces. Dodecanethiol (DDT) is used as an inhibitor for the AS-ALD of ZnO using diethylzinc and H2 O at 120 °C. H2 plasma treatment removes the DDT adsorbed on Cu, forming inhibitor-free surfaces. The ALD-Ru film is then successfully deposited at 220 °C using tricarbonyl(trimethylenemethane)ruthenium and O2 . The Cu/bilayer/Si structural and electrical properties are investigated to determine the diffusion barrier performance of the bilayer film. Copper silicide is not formed without the conductivity degradation of the Cu/bilayer/Si structure, even after annealing at 700 °C. The effect of ZnO on the Ru/SiO2 structure interfacial adhesion energy is investigated using a double-cantilever-beam test and is found to increase with ZnO between Ru and SiO2 . Consequently, the Ru/ZnO bilayer can be a multifunctional layer for advanced Cu interconnects. Additionally, the formation of a bottomless barrier by eliminating ZnO on the via bottom, or Cu, is expected to decrease the via resistance for the ever-shrinking Cu lines.
RESUMEN
The effects of environmental conditions on the interfacial adhesion between screen-printed Ag film and polyimide substrate interface are quantitatively evaluated using the 90° peel test. The adhesion of printed patterns is varied by annealing time and atmosphere conditions. The peel strengths of air, high vacuum, and N2 atmosphere samples increase after post-annealing for 24 h, which are closely related to the curing effect of binder in Ag paste. The peel strengths of air, high vacuum, and N2 atmosphere samples decrease after post-annealing for 48 and 100 h. Peel strengths of samples after 48 h post-annealing in air are lower than in high vacuum and N2, indicating the effects of post-annealing atmospheric conditions on interfacial adhesion strength. The decreased adhesion strength during post-annealing seems to be closely related to Ag2O formation at screen-printed Ag/polyimide. Therefore, the optimum annealing conditions of Ag binder must be carefully applied to obtain maximum interfacial adhesion. Furthermore, it is important to control Ag2O formation during environmental reliability testing.