| AVS 56th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Thursday Sessions |
| Session NS-ThA |
| Session: | Characterization & Imaging at the Nanoscale II |
| Presenter: | M. El Kodadi, LTM-CNRS, France |
| Authors: | M. El Kodadi, LTM-CNRS, France S. Soulan, Georgia Institute of Technology P. Schiavone, Georgia Institute of Technology M. Besacier, LTM-CNRS, France |
| Correspondent: | Click to Email |
In situ , real time control of the different process steps in semiconductor device manufacturing becomes a very important challenge, especially for the lithography and plasma etching processes. We have developed a specific software and hardware tools to perform dynamic scatterometry, using in situ spectroscopic multi-wavelength ellipsometry. This technique is non-invasive, non-destructive optical metrology technique. It uses the analysis of the signature of the light scattered by periodic structure to infer the shape of a feature.
In this study the authors show that dynamic scatterometry can be used for real time monitoring during the resist trimming process of two different resist materials, the M78Y resist from JSR, exposed at 248nm wavelength using an ASML/300 scanner, and the 193 nm resist “JSR 1682” . The etch gases used in this study are HBr and O2.with two different bias power conditions “0 and 50” WBias power. Then we discuss about the influence of chemistries and bias power on the etched profile. We report how the plasma conditions can induce some chemical modifications of the resist films, and we explain how this issue can be addressed in the scatterometric real time control of the resist trimming process. A Jobin-Yvon ellipsometer, capable of real time acquisition of sixteen wavelengths, is plugged onto chamber of a Decoupled Plasma Source (DPS) from Applied Materials. The measurements are made in real time in the etch chamber during the process.
For validation purposes, the same process has been interrupted at several different times and the trimmed feature profiles have been measured using a 3D AFM from Veeco Instruments. The comparison between scatterometry and AFM measurement shows an excellent match for both CD and height parameters with a difference less than 2% .
This proves that dynamic scatterometry provides reliable results and shows a great potential as a real time monitoring technique for etch process control. This characterization technique can be viewed as an invaluable tool for the accurate control of the patterning of current and next generations of semiconductor devices.