AN INTEGRABLE NOZZLE FOR MONOLITHIC MICROFLUIDIC DEVICES

A novel nozzle structure, applicable as part of an integrated microflu idic system, has been fabricated in a (100) silicon wafer, using doubl e-side bulk-silicon micromachining. The nozzle structure contains thre e pyramidal channels in tandem with a square orifice which is the resu lt of anisotropic etching in a bulk silicon wafer. A time-controlled a nisotropic etching procedure is employed to realize such nozzles, whic h have been designed for orifice sizes of 15 mu m X 15 mu m and 60 mu m X 60 mu m. A combination of KOH and EDP etching processes maximizes the process latitudes for controlling the orifice size. Gas-flow measu rement of the fabricated nozzle having an orifice size of 15 mu m X 15 mu m shows a linear relationship between flow rate and pressure diffe rence within the measured ranges of 0-7 ccm min(-1) and 0-80 psi. (C) 1998 Elsevier Science S.A.