[mems-talk] Wetting Agent for Tungsten

[Richard B. Keithley]

Good Morning,

I am following up on a paper in the literature about creating 
pyrrolized photoresist films onto tungsten microwires (125 um in 
diameter).  I first etch the tungsten tip in the shape of a cone, 
remove oxides with HF, clean with electrocleaner, then dip the tips 
into a DQN photoresist a few times to get a 5-10 um coating.  After 
waiting about 15 min for the resist to dry, I bake the electrodes in a 
furnace under forming gas and the photoresist turns into a 
graphite-like substance (probably due to the novolac).  Unfortunately, 
there is tungsten exposed at the tip of the cone.  Does anyone know any 
agent I can use to try and get better adhesion of my photoresist to the 
tip of tungsten cone?  I am limited to organic compounds because I want 
something that will come off easily in the furnace and I do not want to 
add any unnecessary resistance/capacitance to the tungsten.

Thank you and have a great day!

Richard B. Keithley
UNC Analytical Chemistry Graduate Student &
National Defense Science and Engineering Graduate Fellow
Wightman Research Group
Chapel Hill, NC 27599
919-962-1108