Superfilling characteristic and evaluation of chemically enhanced CVD(CECVD) Cu process

A study has been made of the effect of iodine catalysis such as CH2I2, CH3I and C2H5I on the film structure and superfilling properties of CECVD(Chemically Enhanced CVD) Cu process. In order to clarify the separate effect of catalysis, the effect of process condition in metal organic chemical vapor deposition(MOCVD) using (hfac)CuTMVS and/or (hfac)CuDMB liquid precursor with a direct liquid delivery system was also studied by analyzing the behavior of the deposition rate, texture, surface roughness and uniformity with different process conditions such as substrate temperature, liquid precursor flow rate including multi-step flow rate, and hydrogen carrier gas flow rate without chemical enhancer treatment. The treatment of chemical enhancer i.e. catalysis to condition of the optimized MOCVD Cu deposition increases deposition rate, (111) intensity and decreases the incubation time and surface roughness. These results imply that chemical enhancer have surfactant effect which promotes two-dimensional layer by layer growth. It also promotes the formation of bottom-up filling(superfilling), and the increase in grain size. The superfilling behavior of CECVD Cu process depends on process temperature of MOCVD Cu, temperature of catalytic treatment, exposure time, pre-treatment, type of underlayer, condition of Cu seed layer as an adhesion glue layer, and type of chemical enhancer. It was found that the superfilling behavior of CECVD Cu film was strongly dependent on the process temperature. The deposition of CECVD Cu film in the low temperature region below 150 C shows superfilling behavior and void free filling, but shows the conformal step coverage in the intermediate temperature range. The growth of CECVD Cu film does not proceed in a layer by layer manner and becomes agglomerate in the high temperature region above 190 C.