There are occasions when direct write
lithography would be more appropriate than writing a photomask, especially for
prototyping. This requires a focused
laser beam to directly write microstructures with minimum features down to 500
nm. This would be suitable for high quality microstructures in a short
time. Furthermore, it eliminates the
turnaround time required for manufacturing and processing a mask. Its main advantage is that it provides a
contact free exposure and the possibility of a size reduction. It is also quick and easy to adjust a
prototype design. Direct write
lithography could be very convenient for emerging fields like micro-optics and
micro-fluidics.
Using a reversible Photoresist, you can direct
write features into the first layer of photoresist, reverse its polarity, spin
coat another layer and write the second layer of photoresist.
