Hi Tsoll, You can use grayscale mask photolithography to generate slop in SU8 to create your master mold for PDMS...good luck --- Waseem Khan Raja Postdoc Fellow Tufts Unviversity Medford, MA, USA --- On Mon, 2/28/11, Dr. Holger Beckerwrote: From: Dr. Holger Becker Subject: Re: [mems-talk] Sloped microchannel To: "'Tsoll Doiiu'" , "'General MEMS discussion'" Date: Monday, February 28, 2011, 11:42 AM Hi Tsoll, the only reasonable way I know of making such sloped channels is by mechanical micromachining the master, e.g. in PMMA. Precision machining nowadays can make you extremely precise structures (lateral and vertical geometry +-1 µm), it usually takes a quite expensive bit of machinery to do so (e.g. Kern, Precitech, Kugler) but the results are quite amazing. We regularly use precision machining for mold inserts for injection molding of microfluidic channels. The critical bit might be surface roughness, which is higher compared to lithographically defined channels but there are ways of mechanical or chemical polish. With best regards Holger