CAPACITIVE ACCELEROMETER AND ITS MANUFACTURING PROCESS Russian patent published in 1998 - IPC

FIELD: measurement technology; manufacture of small-sized semiconductor capacitive accelerometers. SUBSTANCE: accelerometer has fixed board and frame joined together through dielectric film, with movable board mounted on the latter with aid of flexible jumpers in a spaced relation relative to fixed board. Fixed board is sunk on periphery in regions opposing frame except for sections in the form of projections evenly arranged over frame perimeter; projections are covered with dielectric film; total area of tops of projections contacting the frame is maximum 0.1 of movable board area. Manufacturing process includes shaping silicon fixed and movable boards by etching, fixing movable board to frame by means of flexible jumpers, and joining fixed board to frame through dielectric layer; in shaping fixed board, silicon plate is oxidized through depth of 0.5-1.5 mcm, aluminum layer of 2.0-3.0 mcm in thickness is evaporated, sections uniformly arranged over board perimeter are shaped by photolithography, copper film, 1.0 mcm thick, with adhesive vanadium sublayer is evaporated, photoresist is applied, cuts are made in it corresponding to aluminum sections on periphery and one cut is made in center corresponding to size of movable board, copper thickness is increased ten times by using electrochemical technique, photoresist is removed, evaporated copper and vanadium films are etched, silicon dioxide film is etched. Silicon is etched in alkali solution through depth of 0.3-0.5 of original thickness of plate to shape projections; copper and vanadium are removed in concentrated nitric acid, plate is divided into separate boards, fixed board and frame are aligned with movable board with frame being set on projections, pressure of 1.5-2.0 kg/sq.cm is applied, and heat treatment is conducted at temperature of 600 C for 60 min. EFFECT: improved metrological characteristics of accelerometer, facilitated manufacture. 2 cl, 8 dwg