Letter to the Editor
-- Semiconductor International, 11/1/1998
I would like to clarify a gross inaccuracy that was written in 'Polymer Process Produces Deep Holes with a High Aspect Ratio' (Industry News, August issue, p. 36). The piece inaccurately states that Surface Technology System, STS, has developed a deep silicon etching process that has found many uses in micromachining applications. This is very misleading.
More accurately, STS has licensed this technology from Robert Bosch GmbH, the inventors of this technology. The processing is described in detail in U.S. patent 5,501,893, which is assigned to Robert Bosch GmbH. This is the same process that both Plasma-Therm and Alcatel also license and promote to the MEMS community. In fact, the process results stated by STS are easily obtainable using a Plasma-Therm system. It is generally felt in the MEMS community that STS has not contributed significantly to the technology, even though they have had access to this process for many years prior to Plasma-Therm!!
Dr. Jay N. Sasserath
Vice President, Strategic Marketing
Plasma-Therm, St. Petersburg, Fla. 
