Spectroscopic investigations of plasma damage of kapton

Kapton (polyimide) has been considered a potential candidate for particle reduction in plasma etching chambers. However, it is found that the lifetime of kapton’s ability to trap particles is limited. Beyond this limit, particle contamination becomes serious. In this study, two plasma etching recipes were used to test the particle/polymer trapping efficiency of kapton. Fourier transform infrared (FTIR) and ultraviolet (UV)-visible emission spectroscopies were used to study plasma–kapton interactions. It is found that the functional groups change on the kapton surface as observed by IR has a strong link to the change of features in plasma emission spectra. The increase of IR absorption of $CFx (x=2$ and 3) indicates the growth of fluorocarbon polymer on the kapton surface. The kapton surface was damaged, as is indicated by the change of $C=O,$ $–NH2,$ and $C–H$ IR intensities and the variation of CN and SiF peaks in UV-visible emission spectra. Spectroscopic data show that kapton has a very good particle/polymer reduction efficiency when using a high-polymer recipe but it is not very efficient with an oxygen-rich recipe. Both IR absorption and UV-visible emission data are correlated to interpret the mechanisms of plasma damage of kapton.