Plasma etching of different polydimethylsiloxane elastomers, effects from process parameters and elastomer composition

Plasma etching of three different polydimethylsiloxane elastomers has been studied. One elastomer was a commercially available kit (Sylgard-184) and the other two were made by mixing individual components. The etching was done in a multi-wafer tool. The process gas used in the etching was a mixture of SF6 and O2. The etch rate was measured as a function of pressure for all three materials at the centre and the edge of the etched structures. It was found that fillers in the elastomer reduces the etch rate but has little effect on the shape of the etched surface. Second, it was found that excess of chain ends in the elastomer gives larger changes in the shape of the etched surface, as pressure changes. Third, it was found that loading (reduction of etch rate) is significant in the presence of dummy silicon wafers compared to glass wafers.