Jeffrey, as per my evaporation email, I've had problems with resistive=
 evaportation of Ti onto SU-8 due to sample heating. I don't think the=
 light from my filaments exposes the Ti, as the dep rate from the Ti=
 quickly covers the SU-8 and blocks any further photoabsorption. But if you=
 accidentally hard bake the SU-8 during the dep, it won't develop out the=
 unexposed regions. Monitor your sample with a thermocouple or a thermister=
 if possible.=20

I've been using a little dimpled tungsten boat heater or canoes for Ti.=
 Works fine as long as you heat them fast, dep fast and stop fast.=
 Resistive evaporation makes a lot of heat from that big ohmically heated=
 filament. Ebeam at least mostly just heats the slug of Ti.=20

As for undeveloped SU-8, I've noticed that metal over unexposed SU-8 tends=
 to be a little  'waffley' or 'crinkley' compared to the metal over the=
 exposed SU-8.=20

Oh, and you *must* do a post-exposure bake... or the undensified SU-8 may=
 bubble on pump down. (I forgot once!)=20

-- Jon

---- Message from "Yue Mun Pun, Jeffrey"  at=
 2007-03-03 15:52:56 ------
>Brent,
>Thanks for the recommendation.  Yes, I did try Chromium, which is not as=
 easy compared to Titanium either.  And I know that Chromium is a good=
 adhesion layer for gold too.  The reason for using to Titanium is because=
 Chromium inhibits Poymerase Chain Reaction, while Titanium is=
 biocompatible.  However, I need to evaporate Titanium on uncrosslinked=
 SU-8, which is why I am trying to thermally evaporate Titanium on SU-8.  I=
 am well aware that Titanium is tough to thermally evaporate.  However, if=
 uncrosslinked SU-8 2050 is safe from being crosslinked when Titanium is=
 being deposited in an e-beam evaporator, I would gladly evaporate Titanium=
 in the e-beam evaporator, which is easier by far.