Biomedical Engineering Reference
In-Depth Information
LCST
poly-(NIPAM-AA)
LCST
poly-(NIPAM-NBA)
LCST
poly-(NIPAM-AA)
LCST
poly-(NIPAM-NBA)
LCST
poly-(NIPAM-AA)
LCST
poly-(NIPAM-NBA)
a
b
c
UV
Mask
Water
UV illumination
Photocleavage
First cooling
Pattern
development
Photoresist
Glass
poly-(NIPAM-NBA)
poly-(NIPAM-AA)
n
n
m
m
O
O
NO
2
NH
O
O
NH
O
OH
LCST
poly-(NIPAM-AA)
LCST
poly-(NIPAM-AA)
LCST
poly-(NIPAM-NBA)
e
d
LCST
poly-(NIPAM-NBA)
Adsorbed
protein
Protein
adsorption
Second cooling
Photoresist
removal
0
100 200 300
Lateral position, µm
400 500 600
FIGURE 1.6
Water-soluble.thermoresponsive.photoresist.for.protein.patterning..(From.Ionov,.L..and.
S..Diez,.“Environment-friendly.photolithography.using.poly(
N
-isopropylacrylamide)-based.thermo-
responsive.photoresists,”.
J. Am. Chem. Soc
.,.131,.13315-13319,.2009..Reprinted.with.permission.
of.the.American.Chemical.Society.)
1.3.6 Maskless Photolithography
Photomasks are inconvenient, to say the least. Why can't we fabricate
every
substrate the
way photomasks are fabricated? hat would be too slow, and that is the very reason why we use
photomasks…but for certain applications (mainly the fabrication of microluidic masters), it is
starting to make sense to fabricate the masters simply by raster-scanning a laser over SU-8 pho-
toresist with a photomask generator (essentially, a laser writer). It takes several hours to expose
20 µm
FIGURE 1.7
Laser. lithography. of. 30-
μ
m-thick. SU-8. structures.. (Courtesy. of. Wallace,. P.. and. S..
Braswell,.Nanotechnology.User.Facility,.University.of.Washington,.Seattle,.WA.)
