Structure and Thermal Properties of Thin Film Poly(α‐methylstyrene) Deposited via Plasma‐Enhanced Chemical Vapor Deposition

Plasma‐enhanced (PE) CVD from α‐methylstyrene is a dry method for synthesizing directly patternable sacrificial materials for generating pores or air dielectric layers. Films deposited at low power excitation (40 W) decompose between 65 °C and 75 °C, leave minimal residue following a 400 °C anneal for 2 h, and have spectroscopic signatures of linear poly(α‐methylstyrene) (PaMS) as determined by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Increased plasma excitation power leads to cross‐linking and increased residue after annealing. All films also contain hydroxyl and carbonyl groups after exposure to air. Significant C–O–C inclusion occurs under continuous plasma excitation but not under pulsed‐plasma conditions.