An Alternative to Solder?
A new nanotube-based dry adhesive has been created to
replace solder in circuit-board assembly. The adhesive, which has very high
electrical and thermal conductivity, models its sticking power on the foot of
the gecko lizard. It works without heat or solvents, permitting use in the
vacuum environments used to make chips and in space.
"This will be useful to put electronic components together because the
nanotubes have very high thermal conductivity," said professor Liming Dai
at Ohio's University of Dayton.
Carbon nanotubes, which have very high electron mobility, enable the adhesive
to be used to assemble chips on boards without the heat of soldering. The
researchers are also experimenting with patterning the material onto chips
themselves.
"We grow (the nanotubes) on silicon wafers, because we use silicon wafers
for electronic applications. We can pattern at the microscopic level,"
said Dai. "If you use this kind of adhesive to put transistors together
into circuits, the adhesive will remove the heat generated by the
current."
The adhesive force measured by the researchers was similar to that of a gecko's
foot - up to 100 Newtons per centimeter in the shear direction and 10 N/cm in
the perpendicular direction.
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