HIGH-YIELD BURIED MICROCHANNEL FORMATION FOR DRUG DELIVERY AT THE CELLULAR LEVEL

摘要

Fluidic microchannels can be formed in bulk silicon using wet and/or dry etching through a perforated ceiling structure that is subsequently sealed using deposited dielectrics. Isotropic dry (STS) etching and TMAH result in smoother channel walls than EDP at the expense of less selectivity to p++ silicon ceiling ribs. The size of the etch-access holes is important in achieving high yield, with screen and split-beam structures producing better results than chevron and diagonal-slot structures. Reducing 4μm-wide ribs to 2μm and increasing etch openings from 1.4μm to 2μm produces channel yields above 90%. Neural probes combining chemical delivery with electrical stimulation/recording have been realized successfully.