A thermal microflowmeter has been integrated into a bulk micromachined recording probe to monitor drug delivery in the central nervous system at the cellular level. Based on trench refill and chemical mechanical polishing (CMP) processes, the drug delivery probe achieves a 50µm 2 cross-sectional area and partial or all dielectric channel sidewalls. The flowmeter uses an arsenic-doped polysilicon heater/sensor supported on a dielectric membrane over the flow channel. Efficiencies of 27.2°C/mW are achieved. At input powers of 0.1mW and 0.2mW, the flowmeter can detect volumetric flows of 280pL/sec and 160pL/sec for a channel cross-section of 50µm 2 , corresponding to flow velocities of 5.6mm/sec and 3.2mm/sec, respectively.

No abstract

No abstract