WATER-ADSORPTION AT A POLYIMIDE SILICON WAFER INTERFACE/

Neutron reflectivity (NR) was applied to measure the concentration of water at the buried interfaces between an amorphous polyimide and sili con single crystal wafers. Excess water was discovered within 30 Angst rom of the metal/polymer interface, where the water concentration reac hed 17% (by volume) for the samples without a coupling agent and 12% f or the ones with coupling agent. Beyond the interface, the water conce ntration was measured at 2 to 3%, which is typical of bulk polyimide. The above results demonstrate conclusively the unique power of NR in d etermining water concentration near a buried interface, and provide th e first quantitative evidence for a water concentration profile which peaks in the interface region.