Evaluation of Plasma Damage to Low-k Dielectric Trench Structures by Multiple Internal Reflection Infrared Spectroscopy

摘要

Plasma induced damage on a ~68 nm low-k dielectric trench structure was evaluated and correlated to each plasma processing step using multiple internal reflection infrared spectroscopy (MIR-IR) complemented by XPS and SEM. The plasma stripping process causes significantly more Si-OH and C=O chemical bonding formation and breakage of Si-CH_3 bonds in porous low-k trench structure. Formation and removal of fluorocarbon post-etch residues can be monitored using the IR absorption band at 1530-1850 cm~(-1). The Si-OH content provided by MIR-IR metrology can function as a sensitive and reliable quantitative metric for the rapid assessment of plasma induced dielectric damage.