Dear Erkin, I do know of several places that have created close to 40:1 aspect ratio's in SU-8 using near UV exposure with close control on the process parameters... Including Sandia, Professor Wanjun Wang at LSU and Professor Kyle Jiang at the University of Birmingham in the UK...However, these processes may not be suitable for high volume manufacturing where throughput is a parameter that needs to be considered... Here at MicroChem I can create features down to between 5 to 10um in a 100um thick film of SU-8/SU-8 2000...For these relatively thick films of SU-8 I use a multi coat process so that the final coat (the one that is in contact with the mask) is as uniform as can be...If I attempt to create 100um in a single coat the edge bead is huge and the overall film uniformity is not acceptable to me...I also use a spray-puddle development technique to get the best resolution and structure integrity out of the process.... If you have any specific questions or need technical assistance please do not hesitate to contact me.... Best regards, ------------------------------------ MicroChem Corp. Mark Shaw Epoxy Business Unit - Sales and Technical Support Manager mshaw@microchem.com 1254 Chestnut Street Newton, MA 02464 tel: 617-965-5511 ext 308 fax: 617-965-5818 mobile: 617-407-9490 www.microchem.com ------------------------------------ Message: 3 Date: Sun, 11 Dec 2005 15:44:55 +0800 From: "Peng JIN"Subject: Re: [mems-talk] SU8 maximum aspect ratio To: "General MEMS discussion" Message-ID: <1134287123$22598$70914428@P.Jin@hit.edu.cn> Content-Type: text/plain; charset="gb2312" Dear erkin, I have succeeded to obtain 40:1 in 1000um, and someone in Sadia has succeeded to obtain about 60:1 in 700um. best regards Peng >Hi, > >I want to build vertical SU8 beams on a silicon or quartz substrate, and I >would like to have an idea about the maximum aspect ratio I can get with >thick (>100um) SU8 resist to yield near vertical sidewalls and intact >structures. Could anybody please forward his/her idea on this? >