| AVS 57th International Symposium & Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS2-TuM |
| Session: | Plasma Diagnostics, Sensors and Control |
| Presenter: | G. Padron-Wells, University of Texas at Dallas |
| Authors: | G. Padron-Wells, University of Texas at Dallas P.L.S. Thamban, University of Texas at Dallas J. Hosch, Verity Instruments M.J. Goeckner, University of Texas at Dallas |
| Correspondent: | Click to Email |
Process control in etch plasma systems are often achieved by optical emission spectroscopy (OES) signals. One such application is etch endpoint detection. In systems where plasma emissions are low, OES signals for process control cannot be employed. To address this problem, a versatile electron extraction method has been developed and used in conjunction with an OES diagnostic system to reliably measure changes in gas composition and emission cross sections for CF4 plasma etch environments. An inductively coupled plasma source is employed to source electrons in an excitation region where optical emission measurements are conducted. Unique to this design is the control it offers to measure electron impact optical excitation of gas phase species. Cross section response for Argon emission lines with respect to electron beam energy correlates well with published data. Cross section behaviors for the strongest emission lines characterizing the CFx molecular system are presented. Also, ability to detect 0.1% changes in feedstock gas chemical composition makes this design a highly sensitive end point detection system for analysis of semiconductor process chemistries. Work supported in part by NSF (Grant CBET- 0922962) and Verity Instruments.