| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS-TuA |
| Session: | Fundamentals of Plasma-Surface Interactions I |
| Presenter: | S. Engelmann, University of Maryland, College Park |
| Authors: | S. Engelmann, University of Maryland, College Park F. Weilnboeck, University of Maryland, College Park R.L. Bruce, University of Maryland, College Park G.S. Oehrlein, University of Maryland, College Park C. Andes, Rohm and Haas Electronic Materials D.B. Graves, University of California, Berkeley D.G. Nest, University of California, Berkeley E.A. Hudson, Lam Research |
| Correspondent: | Click to Email |
The modifications of 193nm and 248nm PR blanket materials, patterned structures, and model polymers during and after plasma etching were studied using ellipsometry, atomic force microscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. The plasma parameters examined include bias power, source power and pressure in C4F8/90% Ar discharges. In addition, CF4/Ar chemistries (0-100% Ar) have been examined. We combined these widely varying plasma conditions in a model addressing the photoresist roughening behavior in oxide etch plasmas. The roughness evolution was based on a transfer mechanism by ions and a characteristic roughening behavior based on the energy density present on the PR surface during processing. We found that in our discharges this roughening behavior scales linearly with the energy density present at the surface during the discharge, suggesting an overriding importance of the molecular structure on the roughening behavior. A proportionality of this scaling based on the molecular structure of the PR material was noted. The resulting surface roughness can be predicted if the polymer structure, exposure time and the energy density during plasma processing are known. We also found that the energy density of the surface could be greatly reduced by an increase in etch yield. The etch yield could be effectively increased depending on the oxygen and fluorine surface coverage of the PR material. Our results indicate that either high removal or high roughening occurs during plasma processing, but both parameters cannot be independently optimized.