Photoresist and Etch Residue Removal: Effect of Surface Energy and Interfacial Tension

Abstract

In the fabrication of microelectronic devices and integrated circuits, fluorocarbon post-plasma etch residue removal is an important cleaning process. The low-surface energy and cross-linked nature of residues, combined with compatibility concerns between cleaning solutions and device film materials and structures, make such cleaning and residue removal processes particularly challenging. In addition, development of effective cleaning chemistries is complicated by the variability of etch residue compositions and thus their chemical and physical properties. In this work, the efficiency of cleaning solutions was tested through the investigation of the interactions between “model” films and/or patterned fluorocarbon residues and cleaning chemistry. Measurement and analysis of these interactions to identify possible correlations with observed cleaning efficiency were performed using the Owens–Wendt approach. Comparison of the relative amounts of polar and dispersive interactions between solid materials and the cleaning solutions in combination with estimation of separation energy between the residue and substrate as a function of applied cleaning chemistry offered reasonable correlations with residue removal. This information provides insight into the formulation of cleaning mixtures for fluorocarbon-based residue removal.