Chemistry Reference
In-Depth Information
FIGURE 13.14
Dendrimers with thermally labile t-Boc groups are of use in chemically
amplified resist materials for sub-100 nm lithography.
G4.5 PAMAM (carboxylate surface) dendrimer containing platinum-complexes
was studied [266]. Similarly, G4 PAMAM-OH encapsulating platinum particles
were described [267].
Resist materials are used in lithography to fabricate electronic circuitry and
DRAM (dynamic random access memories). Using dendrimers with thermally labile
end groups (t-Boc), the first example of a chemically amplified lithography resist
materials based on dendrimers was created. With conventional e-beam irradiation,
sub-100 nm lithography produced lines in the 50-100 nm range. It is believed that the
dendritic shape compared to long polymeric chains is responsible for the increase in
resolution (Figure 13.14) [268]. A review on novel organic resists for nanoscale
imaging with chemically amplified cycloaliphatic resists was reported [269].
A new class of thermally responsive dendrimers were recently described. They
are based on a thermally reversible furan-maleimide Diels-Alder reaction with
some poly(aryl ether) dendrons [270,271]. The reversible reaction occurred above
90
C, but the reassembly of the dendrons was possible at 65
C for several days.
Other dendritic thermal decompositions and their mechanisms have been studied
but the applications were not described [272].
13.3.9 Redox Dendrimers
Redox-driven shaving dendrimers use a redox stimuli (with Na
2
S
2
O
4
) for cleaving
peripheral substituted quinone end groups. Reduction of the latter induced an
