| AVS 59th Annual International Symposium and Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS1-TuM |
| Session: | Plasma Diagnostics, Sensors and Control 1 |
| Presenter: | Y. Zhang, Dublin City University, Ireland |
| Authors: | Y. Zhang, Dublin City University, Ireland B.J. Keville, Dublin City University, Ireland C. Gaman, Dublin City University, Ireland A. Holohan, Dublin City University, Ireland M. Turner, Dublin City University, Ireland S. Daniels, Dublin City University, Ireland |
| Correspondent: | Click to Email |
The ever-increasing demand for higher device density in integrated-circuit fabrication has resulted in stringent requirements in respect of quality, reliability and precision of all fabrication processes in semiconductor manufacturing. Reactive Ion Etching (RIE) is a critical technology used at many stages of the manufacturing process. At present, most semiconductor manufacturing equipment is operated in open loop mode. Consequently, key plasma parameters such as ion flux and radical densities at the substrate surface are sensitive to drift in tool subsystems, changes in wall condition and wafer loading, for example. Such disturbances may affect process metrics such as etch depth and anisotropy and result in a significant degradation in device yield and performance.
In this presentation, we describe the implementation of a multi-variable Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) controller to regulate key plasma parameters in an updated Mini-lab RIE 80 capacitively coupled chamber. The custom designed, real-time data-acquisition and control system has been implemented in Labview on a National Instrument CompactRIO real-time controller, which has been interfaced to a hairpin resonance probe and an optical emission spectrometer, the Ocean Optics USB4000. Experimental results are presented which compare the performance of the multivariable LQG/LTR controller to that of a suite of decentralised single-input-single-output (SISO) controllers.
This research forms part of program to implement multivariable closed-loop control on an industrial Electron Cyclotron Resonance (ECR) plasma etch chamber. The presentation concludes by describing progress in this part of the program.