Sealed-type remote pressure-monitoring device and method for fabricating the same

Abstract

Disclosed are a remote pressure-monitoring device and a preparing method thereof. The device comprises a metal electrode on a glass substrate, a capacitive sensor made of a silicon diaphragm, and an electroplated inductor electrically connected, in parallel, with the sensor. The glass substrate and the silicon are electrically bonded to form an LC resonator. For the fabrication of the device, first, a metal electrode which plays a role as a lower electrode for a capacitive pressure sensor is deposited on the glass substrate with the same coefficient of thermal expansion as that of silicon. An inductor is formed at a thickness by copper electroplating, surrounding the metal electrode at a predetermined distance. A silicon substrate is anisotropically etched to form a space for enveloping the metal electrode at a central area and to form a groove around the space. Boron ions are diffused lightly into the space and deeply into the groove to form etch barriers thereat, followed by bonding the silicon substrate on the glass substrate through an electrical contact in such a way that the metal electrode and the inductor are enveloped in the space and the groove, respectively. Then, the silicon substrate is etched out from its rear side to the extent that the etch barriers are exposed.