| AVS 54th International Symposium | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeA |
| Session: | Plasmas and Polymers |
| Presenter: | R.L. Bruce, University of Maryland, College Park |
| Authors: | R.L. Bruce, University of Maryland, College Park T. Kwon, University of Maryland, College Park S. Engelmann, University of Maryland, College Park F. Weilnboeck, University of Maryland, College Park M. Sumiya, University of Maryland, College Park R. Phaneuf, University of Maryland, College Park G.S. Oehrlein, University of Maryland, College Park B. Long, University of Texas, Austin G. Willson, University of Texas, Austin D.G. Nest, University of California, Berkeley J.J. Vegh, University of California, Berkeley D.B. Graves, University of California, Berkeley A. Alizadeh, GE Electrics Global Research Center |
| Correspondent: | Click to Email |
Ar/C4F8/N2 gas mixtures are being used for plasma etching low-k dielectric films. It is not fully understood how addition of N2 affects the polymer surface of an organic masking material in a fluorocarbon-rich plasma environment. Therefore, the effects of N2 addition in fluorocarbon plasma on polymers containing nitrogen (polyvinylpyridine) and without nitrogen (polystyrene) were investigated. The polymer surface after plasma exposure was analyzed using a number of characterization tools: ellipsometry (etch resistance), atomic force microscopy (AFM) (surface roughness), and x-ray photoelectron spectroscopy (XPS) (chemical composition). Through ellipsometric analysis, we found that the etch resistance was dependent on the steady state fluorocarbon (FC) layer created during plasma etching. With AFM, we have shown that the surface roughness decreased with %N2. Using XPS, it was found that while the fluorine content in the polymer surface continually decreased with increasing %N2, the nitrogen content increased until reaching a saturation level. Furthermore, significant differences in etch resistance, surface roughness, and chemical composition were found between polystyrene and polyvinylpyridine. We investigated whether the nitrogen in the polymer enhances the effect of the nitrogen in the plasma during exposure. In addition, we examined the relationship between the reduction of FC film thickness in remote plasma conditions and the enhanced etch rate of polymers in direct plasma conditions.