Jacob, In answer to your questions: 1) 20 um films can be achieved using ~400 rpm. However, standard spinning process will limit your single coat film thickness with AZP4620 to ~32 um (this is spinning at ~200 rpm). I've been successful with obtaining thicker films (in excess of 60 um) in a single coat using a system which integrates a cover with the coating module (an EVG150, to be precise). In general, I've found that using the covered coating module helps to improve uniformity in AZ P4620 and other thick film materials. Do you happen to have access to a system with a covered bowl? 2) There is one fundamental difference between AZ4620 and AZP4620. AZ4620 (which is no longer commercially available) used (Ethylene Glycol Monomethyl Ether Acetate) EGMEA as the casting solvent. This material has been declared as a health risk, with reproductive effects, and so has been replaced with AZP4620, which contains Propylene Glycol Monomethyl Ether Acetate (PGMEA), which is considered to be a harmless solvent. This difference may affect coating parameters somewhat, since EGMEA has a vapor pressure of 5.25 torr, while PGMEA has a vapor pressure of 3.7 torr. Otherwise, I don't know of any difference between the materials. Best Regards, Chad Brubaker EV Group invent • innovate • implement Technology - Tel: (602) 437-9492, Fax: (602)437-9435 e-mail: C.Brubaker@EVGroup.com, www.EVGroup.com This message and any attachments contain confidential or privileged information, which is intended for the named addressee(s) only. If you have received it in error, please notify the sender immediately and then delete this e-mail. Please note that unauthorized review, copying, disclosing, distributing or otherwise making use of the information is strictly prohibited. -----Original Message----- From: mems-talk-bounces+c.brubaker=evgroup.com@memsnet.org [mailto:mems-talk- bounces+c.brubaker=evgroup.com@memsnet.org]On Behalf Of Koby Harel Sent: Sunday, November 23, 2003 2:06 AM To: mems-talk@memsnet.org Subject: [mems-talk] AZ4620 Hi all, I need to fabricate microlens (~400 Micron) and I will use a thick positive AZP4620 photoresist for that purpose. 1. I need the spinning curve to deposit AZP4620 in thickness ranging 20-40 Microns, 2. Is there a difference between AZ4620 to AZP4620 regarding that or is it essentially the same photoresist ? Thanks Jacob Harel Minifab Scoresby _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/