Gert, I have heard reports that AZ5200 series resists can be unreliable from batch to batch, and that formation of the negative slope profile is very dependent on image reversal bake parameters. (i.e. Hotplate must be accurate within 1 degree C, surface of hotplate and bottom of wafer must be very clean) What has your experience been with these resists? I have also heard of a positive resist called BPRS100 made by O.C.G. that forms a layer of lower solubility at the top surface so that a negative tapered profile is obtained with overdevelopment. Does anyone in the MEMS group have any experience with this product? Brian Cunningham Draper Laboratory bcunningham@draper.com