> There are now several resist technologies available for LIGA type work. > > I have not heard of anyone successfully using a thick spun-on PMMA > film. However, if you are interested in using the "PMMA sheet > technique", you should be able to obtain good adhesion to the Ti. > You may, however, be limited with respects to line width (greater than 10 um PMMA widths > should be easy). I believe MCNC wrote all the details up on their web > page. However, a good start is as follows: > > (1) spin-on 1-2 um PMMA, and anneal (WI use to anneal to 180 C; slow > ramps were helpful) > (2) use a high quality PMMA for the sheet material (minimum low MW > fraction, not crosslinked; we use to use: Goodfellow CQ grade - cell > cast in England by ... can't remember). Make sure the bond surface is clean AND DRY. > (3) solvent bond using MMA, capillary action to wet the interface > (minimize this volume = solvent affected zone formation) > (4) let stand for several hours (overnight); lightly weighted couldn't hurt > (5) mill (fly cut) PMMA to desired thickness; diamond tool works best > (6) DO NOT anneal! > > Both Ti and Cr form an "acidic" oxide. Since PMMA is "alkaline", you > can obtain a good bond. MMA solvent is very compatible with PMMA, and > should not displace the already absorbed PMMA (from the spun-on and > annealed layer). Dissolution of the entire 1-2 um does, and should, > occur. > > Let me know, > Ken