Bonding Structure of Model Fluorocarbon Polymer Residue Determined by Functional Group Specific Chemical Derivatization

Abstract

Using FTIR, XPS and SEM, the bonding structure of model fluorocarbon polymer residues (6–28 nm) deposited on 90 nm low-k dielectric trench lines was determined to consist of amorphous fluorinated polymers with significant branching, C=C and C=O functional groups. The carbonyl functionality was identified by 2,4-dinitrophenylhydrazine derivatization. The olefinic linkages with various degrees of fluorination was established by Br2 addition to C=C bonds in model fluoropolymer. Reductive defluorination of C-F bonds was carried out using naphthalenide radical anion treatment. Adding O2 and NF3 to CHF3/C4F8/Ar plasma changed coating profiles and resulted in a disproportionate decrease of carbonyl and olefinic functionalities.