Silicon-micromachined Microneedle for Suction and Injection of Bio Samples

Silicon-micromachined microneedle for a biofluid diagnosis system is developed. To fabricate microneedles, two sets of processes are used. One is making buried microchannels in silicon wafer using silicon isotropic etch with a SF6 plasma and then trench-refilling. The other is releasing the body of the microneedle by deep silicon etch. The microneedle has a 4 mm-length and about 12 $\mu\textrm{m}$ diameter buried microchannel, a 1.5 mm$\times$l.5 mm-area reservoir, and about 180 $\mu\textrm{m}$thickness body. Preliminary results indicate that microneedles are capable of flowing fluidic samples. The microneedle with a buried microchannel is expected to be integrated with in vitro diagnosis systems and microfluidic devices.