An ultraminiature solid-state pressure sensor for a cardiovascular catheter

Abstract

An ultraminiature solid-state capacitive pressure sensor that can be mounted in a 0.5-mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart is described. The transducer consists of a silicon 290*550*1.5- mu m/sup 3/ microdiaphragm surrounded by a 12- mu m-thick silicon supporting rim, both defined by the boron etch-stop technique. The transducer process features a batch wafer-to-glass electrostatic seal followed by the silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. A hybrid interface circuit chip provides a high-level output signal and allows the sensor to be compatible with use on a multisite catheter having only two leads.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>