In ULSI devices, many new requirements appeared for contact processes. These are highly selective oxide etching and less microloading in quarter micron contact holes. High density plasma sources have many advantages to meet these requirements, such as low pressure and proper process range for quarter micron devices. In this study the composition and structure of oxide etch polymer in inductively coupled plasma sourec were studied by XPS to analyze the characteristics of high density plasma. The experiments for this study were performed in a high density plasma chamber employing inductively coupled plasma source. Three kinds of post etch treatments wee used for the analysis of the composition and the characteristics of the oxide etch polymer. The depth profile and composition data of the polymer residue were obtained by XPS analysis.