Paper PS2-ThM9
Plasma Process Development and Control with Real-Time Critical Process Parameter Detection at the Wafer Surface

Thursday, October 18, 2007, 10:40 am, Room 607

Improved semiconductor manufacturing equipment / process diagnostics and control are ever more critical as the push toward ever smaller microelectronics device geometries continues. This is especially true for the fabrication process of controlled destruction: plasma etch. Improved plasma etch process diagnostics can be advantageous for initial development of stable processes to enable fast and profitable manufacturing ramp-up as well as assuring well-matched process results from the multiple plasma processing chambers required for volume manufacturing. Traditionally the focus of diagnostics and control has been on monitoring process chamber inputs (e.g. RF Power, pressure, gas flows, etc.) and outputs (e.g. product critical dimensions, etch rates, particle tests, etc.). Sensors which monitor the average plasma environment (e.g. plasma emission monitoring, advanced RF sensors, etc.) have further improved equipment and process control. Improved technologies now make possible process variable measurement directly at the wafer surface by incorporating sensors into an autonomous data collection sensor wafer. We present the results of such a wireless sensor wafer containing an array of temperature sensors to address issues of process stability and chamber matching. We will show how the unique properties of the thermal â?ofingerprintâ? of the actual plasma process measured near the wafer surface can be used to detect and correct differences between chambers and control for shifts following critical hardware replacement. In addition an example of the potential for process instability detection by thermal fingerprint on the wafer during development instead of during product ramp-up will be presented, showing the advantages and increasing necessity for time-resolved critical process parameter detection at the wafer surface.