| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Friday Sessions |
| Session PS2-FrM |
| Session: | Plasma Processing for 3-D Integration, Photonics, Optoelectronics, and Memory Devices |
| Presenter: | Y. Morikawa, ULVAC, Inc., Japan |
| Authors: | Y. Morikawa, ULVAC, Inc., Japan T. Murayama, ULVAC, Inc., Japan K. Suu, ULVAC, Inc., Japan |
| Correspondent: | Click to Email |
High-density of thru silicon via (TSV) is indispensable to the utilization and improvement in performance in 3D-LSI. Advanced high aspect ratio (A/R) TSV etching technologies are required for high-density TSV formation. We have developed a new etching system for TSV and MEMS application. This System provides combined plasma of magnetic neutral loop discharge (NLD) plasma and a sputtering system, which is named as NLD-Si.1 For high rate silicone etching, it is very important to understand not only high density of the plasma generation but relation between fluorine diffusion (Z: distance of a wafer stage and NLD plasma) and the etching characteristic. In this study, a novel RF antenna ‘multi slit rf antenna’ has developed for the purpose of high rate etching. The number of slits of the antenna was increased from single line to three parallel lines to extend inductive coupling discharge region. Therefore, high-density generation of both of ion radicals is possible. Each slit interval is 25 cm. And, it is the feature that inductance (L) of this antenna is 0.52 uH and it is low L antenna. As a result of performing electron density measurement of the NLD plasma using this MS-RF Antenna, it succeeded in the high-density plasma production of 1x1012 / cm3 by the process pressure of 2 Pa. Next, Si etching process development was performed using the Advanced NLD-Si etcher, which introduced a wafer stage elevator system. Si etching characteristics employing advanced NLD plasma were studied with respect to distance from an antenna. As a result, improvement in the etching rate of 2.5 times or more was realized as a result of optimization of the distance from NL. And, when process pressure and flow rate conditions were made to optimize, about 5 times the etch rate UP was achieved. Finally, the pattern of line width 1um attained the anisotropic etching of 8.5 um/min using Advanced NLD-Si etcher.
1 Y. Morikawa, et al.; Thin Solid Films 515 (2007) 4918.