> 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