A novel technology for fabricating microneedle of SU-8

This paper reports a micro sampling actuator driven by electromagnetic force designed and fabricated by a novel MEMS technology with SU-8 photoresist structure. The actuator consists of a microneedle, a microchannel, a reaction chamber, electrodes and permanent magnet arrays. It should be driven bi-directionally and linearly by the magnetic field outside. The structure and fabrication technology of microneedle are introduced. A multisteps exposal and final developing method of SU-8 photoresist is presented as a novel technology for forming the microneedle. A prototype of microneedle actuator has been developed with the size of 600 μm × 800 μm × 40 μm, and aperture section 20 μm × 20 μm. Some of the photographs of the structure are given by SEM or camera and some problem are discussed in the paper. This actuator may be served as a sampling or measurement device in biochemical microsystem.