An intraocular pressure sensor based on a glass reflow process

Abstract

This paper presents an intraocular pressure sensor fabricated using a new process that reflows glass into DRIE-etched silicon cavities to form three-dimensional microstructures. The capacitive pressure sensor is formed using a 4μm thick boron etch-stopped silicon diaphragm having dimensions of 0.85mm x 1.65mm. The sensor operates in touch-mode with a linear response and sensitivity of 26fF/mmHg, resolving better than 1mmHg over a 650-850mmHg dynamic range. Vertical silicon feedthroughs in the glass provide electrical access to the sensor. This pressure sensor is part of an intraocular microsystem being developed for monitoring the eye pressure of patients diagnosed with glaucoma.