EELS chemical bond characterization of process induced damages in low-k dielectric films

EELS chemical bond analysis has been used to characterize etching process induced plasma damages in low-k SiCOH materials. EELS can provide not only the information of element distribution, but also the insight of chemical bonding status. Through applying the Maximum-likelihood deconvolution to EEL spectra, minor but critical changes in EELS core loss near edge fine structures can be clearly revealed. After comparing Si L_2,3 edge and O K-edge with literature simulation results, Si=O double bonds were proved to be generated by the oxidizing etching plasma at the trench side wall. This work can help to understand plasma reaction mechanism with SiCOH materials and thus can help new process development.