Philippe Maquin

High-etch-rate anisotropic deep silicon plasma etching for the fabrication of microsensors

Dry plasma etching can offer many advantages in the fabrication of MEMS because of its anisotropic etching behavior, high etch rate, and its compatibility with traditional IC processing. A patented high density inductively coupled RFIC plasma source with independent source power and substrate bias control has been developed by Alcatel for deep etching of silicon. With the optimization of hardware and process parameters in a Fluorine based chemistry, processes with silicon etch rate up to 6 micrometers/min, etch uniformity better than +/- 5 percent, Si:SiO2 selectivity of more than 150:1, Si:photoresist selectivity of more than 50:1, etch depths of greater than 250 mm and profile angels of +/- 1 degree have been demonstrated. The silicon etch rate increases with increasing source power and Si:SiO2 selectivity increases with decreasing substrate bias. Substrate temperature can be maintained between -120 to +20 C during processing. The process parameters can be adjusted to give the desired performance for a particular application. Process results obtained at room temperature and at lower temperatures for different applications will be presented. The results indicate that this technology is a promising candidate for micromachining. The tool can be configured for production applications with vacuum loadlock and automated wafer handling.

High etch rate, deep anisotropic plasma etching of silicon for MEMS fabrication

MEMS fabrication faces multiple technological challenges before it can become a commercially viable technology. One key fabrication process required is the deep silicon etching for forming high aspect ratio structures. There is an increasing interest in the use of dry plasma etching for this application because of its anisotropic (i.e. independent of silicon crystal orientation) etching behavior, high etch rate, and its compatibility with traditional IC processing. Alcatel has developed a patented inductively coupled high density plasma source which delivers high etch rate, uniform, anisotropic silicon etching to depths as deep as 500 micrometers . This plasma source has been used for fabricating devices such as accelerometers, yaw rate sensors etc. Etch process performance data on some of these devices will be presented. Thus the Alcatel deep etching system provides the enabling technology requires for deep silicon micromachining of microsensors.

Innovative integrated plasma tool for process and exhaust monitoring

Vacuum-level problems in semiconductor process tools -- from leaks or contamination -- can significantly reduce product yield and tool availability if not detected quickly. Here we present a portable and compact plasma sensor which can monitor the fingerprint of effluent from the process chamber to the exhaust piping by optical emission spectroscopy. The device and tests to monitor and control semiconductor process are described. Further applications such as effluent treatment are tackled.