Development and Metal evaporation
After the electron beam broke the polymer into fragments, the exposed
resist would be dissolved by a developer solution such as MIBK (Methyl
Isobutyl Ketone). MIBK is a strong developer so it can remove parts of the
unexposed resist. By adding IPA (Isopropyl Alcohol) to the developer so
that the MIBK solution becomes weaker.
In fact, we adopted two types of development solution. First, dip
the chip in developer which is dissolved 1:3 in MIBK:IPA; MIBK (methylisobutylketon)
in IPA (isopropanol) for 45 seconds. Chip will be sunk in
the second developer which is Ethyl Glycol Monomethyl Ether in methanol
with ratio 1:2 for 7-10 seconds.Following, samples will be evaporated with metal materials. In order
to start running UHV, we need to turn the cool water line on, supply
nitrogen gas to cool down the main chamber, and check pressure of the
main chamber ( 10?9 mbar). Samples were fixed on sample holder and
screwed to hand tightness. We place sample in loading chamber and
transfer it in a main chamber. Then, the desired metal is selected and
the adjusted data are selected on the control box. In this experiment, I
preferred Titanium and Gold. Subsequently, we turn on the power and
adjust beam, current, amplitude which suit the evaporated metal