Development of a novel wafer-probe for in situ measurements of thin film properties

Abstract

We report a new development of a diagnostic technique, referred to as the wafer probe, which enables us to qualitatively monitor the plasma-induced changes in thin film dielectrics, in-situ and in real time. The wafer probe is an adaptation of the well-established ion flux probe technique, also known as RF biased or pulse biased planar Langmuir probe. This technique utilises the top surface of a tile cut from a multi-layer wafer as the probing area. This technique was successfully used to characterise different plasma conditions and monitor the plasma-induced changes in the thin layers of the tile, e.g. a porous organosilicate-glass low-κ dielectrics. The wafer probe was used to monitor the different effects of an argon and a hydrogen plasma on low-κ dielectrics, as well as to monitor the etch rate and endpoint of an Ar/SF6 plasma.