Abstract

The residual weight of a bottom anti-reflective coating (BARC) sample after microwave digestion was successfully used as an indicator to evaluate the digestion kinetics. The weight degradation rate was independent of the sample weight under various temperatures, but was strongly dependent on the digestion acid volume and the digestion temperature. The temperature dependence of the weight degradation coefficient was effectively modeled by the Arrhenius equation. Furthermore, the activation energy for digestion (0.39 kcal mol⁻¹ for the BARC sample) was independent of the digestion acid volume. Mathematical modeling for prediction of digestion efficiency for the BARC sample was achieved by employing digestion kinetics as the backbone. With the empirical fitting of the pre-exponential factor, a novel equation incorporating the temperature, digestion acid volume, digestion time and sample weight was developed. Both gravimetric analysis and model simulation were performed to evaluate the feasibility of the one-step microwave digestion process.