The Role of Gas‐Phase Reactions during Chemical Vapor Deposition of Copper from (hfac)Cu(tmvs)

Abstract
The chemistry of copper chemical vapor deposition (Cu‐CVD) from the precursor (hfac)Cu(tmvs), where hfac = 1,1,1,5,5,5‐hexafluoroacetylacetonate and tmvs = trimethylvinylsilane, on sputtered titanium nitride (TiN) films was investigated using a hot‐wall tube reactor. We found that gas‐phase reactions contribute to Cu deposition and there is negligible contribution of direct surface decomposition of source precursors. The weak Cu‐(tmvs) bond is cleaved by heating via gas‐phase reactions and the intermediate Cu(hfac) is the real film precursor. Film deposition in a macrocavity confirmed the presence of gas‐phase reactions, because film growth rates increased with increasing volume/surface ratio of the macrocavity. Above 180°C, gas‐phase reactions for producing the intermediate species is the rate‐limiting step and limits the growth rate. Below 145°C, the surface reaction of intermediates limits the growth rate. The rate constants of the gas‐phase and surface reactions are [1/s] and [m/s], respectively, where and T equals; temperature in kelvin. The growth rate profiles agree very well with those predicted using the reaction mechanism and rate constants obtained in this study. This reaction model and kinetic information can be used to optimize reactor design for uniform film growth.
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