| AVS 60th International Symposium and Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThM |
| Session: | Plasma Modeling |
| Presenter: | T. Kubota, Tohoku University, Japan |
| Authors: | T. Kubota, Tohoku University, Japan M. Sato, Harada Corporation, Japan T. Iwasaki, Mizuro Information & Research Institute, Inc., Japan K. Ono, Mizuho Information & Research Institute, Inc., Japan S. Samukawa, Tohoku University, Japan |
| Correspondent: | Click to Email |
Plasma etching is widely used for the fabrication of semiconductor devices and MEMS. However, irradiation damage and etching profile anomalies are severe problems for the plasma processes. We are developing a system to predict the etching profile and plasma irradiation damage by using a combination of the process monitoring on the sample stage of the plasma chamber (on-wafer monitoring) and a computer simulation, and are promoting the commercialization of this system [1]. We have already developed a sensor to measure the differential charge-up between the top and bottom of the high-aspect-ratio hole structure (on-wafer charge-up sensor) and have presented a concept of the charge-up simulation [2]. Here, we developed a calculation based on the on-wafer charge-up sensor measurement that enables for the fusion of the measurement and simulation.
The calculation was performed in two steps. First, a calculation is conducted to determine the situation in the sensor. Here, we developed a calculation to obtain the incidence condition of the ions and electrons from the measured value of the charge-up voltage. A high-speed algorithm (ICCG method) is used to obtain the electric field distribution because the calculation needs iteration to converge the charge-up voltage into the measured value. Second, subsequent calculations are conducted to obtain the charge-up voltage and ion trajectory of an arbitrary etching profile using the ion/electron incident condition obtained from the first calculation.
An on-wafer charge-up sensor with an aspect ratio of 10 was used for the plasma measurement. Then, the calculation was performed. As a result, it was predicted that etching is possible up to aspect ratio of 30, but the etching profile would be anomalous if the aspect ratio is more than 20.
This indicates that the etching profile of an arbitrary structure can be predicted based on a measurement and computer simulation.
[1] http://www.mizuho-ir.co.jp/solution/research/semiconductor/fabmeister/onwafer/index.html (in Japanese)
[2] H. Ohtake et al., Jpn. J. Appl. Phys. 49, 04DB14 (2010), B. Jinnai et al., J. Appl. Phys. 107, 043302 (2010)