CAPACITIVE PRESSURE SENSOR CELLS OR DIFFERENTIAL PRESSURE SENSOR CELLS AND METHODS FOR MANUFACTURING THE SAME

摘要

These capacitive pressure sensor cells have joints between substrates and diaphragms being both pres-sure- and/or tension-proof and high-vacuum-tight and long-term-stable. The sensor cell comprises a ceramic substrate (1) having a cylindrical surface (11), a major surfaces (12, 13). The major surface (12) includes a concave central area (121) merging, in the direction of and up to said cylindrical surface (11), into a convex surface (124) having a vertex line (125) and forming a planar ring surface (126) in its area. An electrode (122) is located in the concave area (121). An electrical connection (123) extends from electrode (122) through the substrate (1) to surface (13). A ceramic diaphragm (5) has a planar inner surface (51) on which an electrode (52) is located and which rests on the ring surface (126) of the substrate (1). The diaphragm (5) is joined to the substrate by an active brazing solder forming a circumferential wedge zone (91) in the area of the substrate between the ring surface (126) and the cylindrical surface (11). An electrical connection to the electrode (52) is made through the wedge zone (91). Respective differential pressure sensors can comprise a central substrate (2) and two outer diaphragms (61, 71) or a central diaphragm (8) and two outer substrates (3, 4).