Bandgap measurements of low-k porous organosilicate dielectrics using vacuum ultraviolet irradiation

Abstract

Vacuum ultraviolet (VUV) photoemission spectroscopy is used to investigate the effect of VUV radiation on porous organosilicate (SiCOH) dielectrics during plasma processing. By comparing photoemission spectroscopic results before and after VUV exposure, VUV irradiation with photon energies less than 9.0 eV was found to be beneficial in depleting accumulated charge in SiCOH films while VUV photons with higher energies did not have this effect. Moreover, VUV irradiation with 8.9 eV photons depletes the most charge. From this result, it can be concluded that 8.9 eV is the bandgap plus the electron affinity energy of SiCOH dielectrics.