Paramagnetic Defects Generation and Structure Change in the Porous Low-k SiOCH Films with Excess Ultraviolet and Electron-beam Curing

Abstract

We have studied in detail the paramagnetic defect generated in the porous low-k SiOCH films, which is called as Tb center with the oxygen-carbon mixed back bonds. We baked the SiOCH films in vacuum at the temperature from 600oC to 1000oC, which could correspond to local temperature enhancement when UV/EB curing and Joule heating in circuits. We have found that the amount of the Tb center increased abnormally around the temperature 775oC by ESR spectroscopy. Moreover, we have observed 30%-volume shrinkage by ellipsometry and network change from cage link to ring link by FTIR spectroscopy. These phenomena might be concerned to a crush of micro holes wrapping Si-CH3 end groups. Therefore, we consider that the generation of the Tb center indicates the quality change of the porous low-k SiOCH films as for the ULSI reliability.