The curing kinetics of polyamic acid in the presence of water vapor

Publisher Website
Google Scholar
Abstract
Polyimides (PIs) are used extensively in integrated circuit fabrication due to their attractive physical properties. Variations in physical properties due to variations in processing and sensitivity to moisture can lead to reliability problems for microelectronic applications. We present the details of exposure of polyamic acid (PAA) to 85 °C/85%RH and to 85 °C/dryN2 as part of a long term study of PI degradation. The PAA under study is formed from the polycondensation of pyromellitic dianhydride (PMDA) and oxydianaline (ODA) in N-methyl pyrrolidone. The acid was spun onto two inch silicon wafers coated with chromium. The PAA cure was followed with electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared (FTIR) spectroscopy. Results show that the presence of water vapor during heating dramatically raises the initial rate of imidization. Measurements indicate the PAA is 6% cured after 72 h in the 85 °C/dry environment while the PAA is 68% cured after 72 h in the 85 °C/85%RH environment. Spectroscopic data confirm that both the surface and the bulk are affected by exposure to the humid environment.

This publication has 0 references indexed in Scilit: