Secondary ion mass spectrometry (SIMS) characteristics of various FSG capping layers

Abstract

To fill the gap of films for metal-to-metal space, High density plasma fluorinated silicate glass (HDP FSG) is used due to various advantages. However, FSG films can have critical drawbacks such as bonding issue of top metal at package, metal contamination, metal peel-off, and so on. These problems are generally caused by fluorine penetration out of FSG film. Hence, FSG capping layers such like SRO (Silicon Rich Oxide) are required to prevent fluorine penetration. In this study, their characteristics and a capability to block fluorine penetration for various FSG capping layers are investigated through SIMS and FTIR analysis. As a result of SIMS analysis, SRO using ARC chamber and SiN film snowed good capability in blocking fluorine penetration. Moreover, the sameness in their FTIR profiles is the presence of Si-H bond at 2175-2300 cm-1. Therefore, we concluded that Si-H bond at 2175-2300 cm-1 of FSG capping layers plays a key role to block fluorine penetration as well as dangling bond.