Hi All - About two weeks ago I inquired: > Anyone happen to know a set of conditions for patterning an > AZ type resist at 10-20 microns thick? I got many responses, condensed below for anyone interested in the summarized answers. Thanks very much to everyone who replied! Marc Unger Caltech Applied Physics, ungerm@cco.caltech.edu ***************** Shipley does make a thick resist. Its the SJR 5700 series. I use SJR 5740, which is is the 15 to 20 um thick version. I like this resist alot. It works well. The processing is very similar to normal resist, except that after spinning the resist must 'rest' on the chuck for 6 minutes before softbake (the resist needs to relax). BTW the resist immediately after spinning will look horrible, don't worry, let it rest. The softbake is on a hot plate (not a vacuum hot plate) for 6 minutes and the development takes 6 to 7 minutes (in shipley 354). The resulting pattern has nice vertical sidewalls and sticks well to metal films (I haven't used it on oxide or SiN) [Ken Westra, ken@amc.ab.ca] ****************** AZ 4620 spun at 2k rpm will give you about 9.5-10 um [Thomas Rocco Tsao] ****************** AZ 4620 at 3000 rpm is ~9 u. Try 1500 rpm or so. [Jason Tauscher Silicon Designs, Inc. Jason@SiliconDesigns.com (425)391-8329] ****************** One way to achieve this is to use a thick resist - something like AZ4620 (I thinks Shipley also makes a thick resist?). This type of photoresist can be spun on with different thicknesses (up to 100um thick) by varying the rpm spin speed and time. [Angela Rasmussen The George Washington University The Institute of MEMS and VLSI Technologies ****************** AZ4903 can be spun on at 4500 rpm and baked for 90s at 115C. This will supply you with a 10 um film. For resist layers thinner than 16 um, simply slow the spin speed. Another positive resist that can be used for thinner films is Shipply 1045. You should be able to get this information easily from the resist manufacturers. [John Williams MEMS Network Engineer Cornell Nanofabrication Facility M103 Knight Laboratory Cornell University Ithaca, NY 14850 Ph. (607) 255-2329 x 129 Fax (607) 255-8601 williams@cnf.cornell.edu] ****************** Using Hoechst's AZ4562, we get 12 micron patterns with the following conditions: -80" spinning at 1000 rpm -30' softbake at 100C -90" illumination at 5 mW/cm2 -developing using AZ531 developer -hardbake [Dirk De Bruyker K.U.Leuven, Dept. Esat-Micas Kard. Mercierlaan 94, B-3001 Leuven, Belgium Tel: +32 16 32 1700 Fax: +32 16 32 1975 E-mail: Dirk.DeBruyker@esat.kuleuven.ac.be http://www.esat.kuleuven.ac.be/~debruyke] ****************** I have exposed AZ4903 resist with an i-line 10:1 reduction stepper. At 4500 rpm, the resists spins out to ~12 microns. Prebake done at 115 C for 1.5 min. Holdtime for 45 minutes to dissipate air bubbles in resist to avoid focus problems. Exposure time in stepper ~11 secs per die which is quite long. It is probably better to break up the exposures and focus the stepper and different levels in the resist to get better quality features but my features were quite large, 15 to 100 microns. Developer needed is AZ 421K. [Mark, mez2@cornell.edu] ****************** Try a photoresist called SU-8. It can be patterned to >100 microns high with great resolution. Try electronic visions in Arizona to find out more about the resist. [BobHendu@aol.com] ******************