A high-performance silicon micropump for an implantable drug delivery system

This paper describes the design and the measurement results of a new silicon piezoelectric micropump developed to be the heart of an implantable drug infusion system. The device is based on silicon bulk micromachining, silicon pyrex anodic bonding and piezoelectric actuation. This pumping mechanism has been designed for maximum safety and reliability together with high open-loop accuracy (/spl plusmn/10%) in a low flow rate range (0-100 /spl mu/1/h). It ensures constant stroke volume (150 nl) over a wide range of working conditions through the implementation of a double limiter, controlling the range of the pumping membrane. Consequently, the flow rate is linear with actuation frequency and virtually insensitive to inlet and outlet pressure, actuation voltage, temperature, viscosity and aging. The pump is self-priming with a stroke over dead volume ratio /spl Delta/V/V/sub 0/=1.15. It also features an on-chip barrier filter for particle protection and a functional detector. More than 100 pumps of the last generation have been fabricated and fully tested.