Can someone tell me typical etch rate, aspect ratio of deep RIE of silicon? Any commercial facilities that can do DRIE? How would I estimate the cost of a DRIE process? I need a 25um deep etch from one side, then a through etch from the other. Wafer is 4 inch, about 300um thick. TK Wang ________________________________________________________ NetZero - We believe in a FREE Internet. Shouldn't you? Get your FREE Internet Access and Email at http://www.netzero.net/download/index.html