[15a-301-1~7] 8.2 Plasma measurements and diagnostics

[15a-301-1] Estimation of Etching Rate Distribution Using Multiple Optical Emission Spectroscopy

〇Soichiro Eto¹, Takeshi Ohmori¹, Satomi Inoue² (1.Hitachi R&D Group, 2.Hitachi High-Technologies Corp.)

Keywords:plasma, monitor, optical emission distribution

Precise control of the critical dimension is necessary in the etching process for the next generation semiconductor manufacturing. Feedback control of the average of the critical dimension for each wafer or lot has been performed using the optical emission intensity of plasma or the etching rate of the wafer, etc. In order to control the in-plane distribution of the critical dimension in wafer, it is necessary to monitor the distribution of the etching rate which highly correlates with the critical dimension.
In this study, we developed an estimation method of the etching rate distribution using the optical emission distribution of plasma. Multi optical emission spectroscopy system which measures plasma light at multiple positions above the wafer from the lateral direction of the chamber using spectroscopes was used. As a result of correlation analysis between the optical emission distribution at each wavelength and the etching rate distribution, it was found that the etching rate distribution can be estimated using the optical emission distribution of the reaction product.