Ceramic Tape-Based Meso Systems Technology

Abstract

Abstract Ceramic tape technology was initially developed for efficiently manufacturing interconnects and hybrid microelectronics circuitry through sequential printing and firing of conductor, resistor and/or dielectric paste formulations onto a substrate. Recently, it has been recognized that ceramic tapes can also be used as an efficient and convenient medium for the manufacturing of meso-scale electro-mechanical systems. In the green (pre-fired) state, the ceramic tapes consist of alumina particles, glass frit, and organic binder; and they are soft, pliable, and easily machinable. In each layer, one can machine flow conduits and mechanical devices and print electronic circuits. Very many layers can be stacked together to form complicated, three-dimensional, monolithic structures. These layers can be laminated and sintered. During the sintering process, the organic binder burns out, the glass flows, and the material hardens. It is possible to cast tapes of various ceramic composition to obtain desirable properties. The paper describes mechanical, chemical, and thermal machining of prefired Low Temperature Co-fired Ceramic Tapes (LTCC); the dimensional changes occurring during the lamination and sintering processes; the use of sacrificial layers to prevent the sagging of internal suspended structures during the lamination and firing processes; the bonding of tapes to alumina, silicon, glass, and metals to form a hybrid technology; and the manufacturing of microchannels and a flow sensor in ceramic tapes. Packaging is widely considered to be the Achilles heel of silicon-based MEMS technology since it is difficult to interface silicon MEMS devices with each other and fabricate relatively large, three-dimensional structures. Low Temperature Co-fired Ceramic Tapes (LTCC), the packaging material of choice in the electronics industry, hold the promise of alleviating some of these difficulties.