Dissolution of copper and copper oxide in aqueous solution containing amine or carboxylic acid

초록

Using a component having an amine group (-NH2) or a carboxyl group (-COOH) for a cleaning solution, the etching rates of copper oxide and copper were analyzed by measuring the solubility of copper to evaluate the etch residue removal properties. Based on this, it was attempted to establish the basis of a cleaning process for removing etch residues in the copper back end of line (BEOL) process. In addition, the etch rate and surface structure change of fluorine-doped fluorosilicate glass (FSG), Black Diamond (BD), and methyl group-doped organosilicate glass (OSG), which are low-k dielectric materials, were analyzed. The copper oxide etching rate of the component having an amine group showed a tendency to increase as the basicity of the solution increased. Also, the solubility of copper oxide in the amine solution decreased with the increase of the carbon length in the amine molecular structure. The solution having a carboxyl group compared to the amine group has a high etching rate for the low-k dielectric material. The amine component showed reactivity only in the basic region and, on the contrary, the carboxyl group component is reactive only in the acidic region.

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