| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS-MoM |
| Session: | Advanced FEOL / Gate Etching I |
| Presenter: | Maxime Darnon, CNRS-LTM, France |
| Authors: | M. Darnon, CNRS-LTM, France M. Haass, CNRS-LTM, France P. Bodart, CNRS-LTM, France G. Cunge, CNRS-LTM, France C. Petit-Etienne, CNRS-LTM, France M. Brihoum, CNRS-LTM, France R. Blanc, CNRS-LTM, France T. David, Cea Leti Minatec Campus, France E. Pargon, CNRS-LTM, France L. Vallier, CNRS-LTM, France O. Joubert, CNRS-LTM, France S. Banna, Applied Materials, Inc. T. Lill, Applied Materials, Inc. |
| Correspondent: | Click to Email |
The etching processes for integrated circuits fabrication becomes extremely challenging when the devices dimensions are downscaling and the etch process has to stop on the ultra thin layers (less than 2nm) of materials. Perfect control of the passivation layers and mask erosion are required to precisely control the patterns profiles, which necessitates using flows and energies of plasma species in ranges which can not be attainable with current plasma technologies. In addition, limiting the plasma induced damage to thin layers requires very low ion energies which are not accessible in current plasma technologies. One promising solution is to pulse the plasma in conventional industrial reactors at very low duty cycle. Using this solution, the ratio of radicals and ions as well as their energy can be fine tuned in ranges that are unreachable otherwise, and very low energy ions are produced which strongly minimizes the damage to the thin layers exposed to the plasma.
Experiments are performed on a 300mm diameter Inductively Coupled Plasma chamber commercialized by Applied Materials (DPSII G5) equipped with the pulsync system to enable plasma pulsing in an industrial reactor.
In this paper, we will show how plasma pulsing can be used to improve uniformity and pattern profiles by better controlling the passivation layer formed on the patterns sidewalls during the etching. In addition, we will demonstrate that the reduction of the average ion energy as well as the use of molecular ions decreases mask erosion, as well as damage to ultrathin etch stop layers. Morphological characterization, surface characterization and plasma diagnostics will be correlated to explain the mechanisms responsible for the process improvement.