Effects of Silver Paste Application on Embedded Channels in Low Temperature Co-Fired Ceramics

A monopropellant micropropulsion device is being developed in low-temperature cofired ceramics (LTCC). The device uses catalytic decomposition of hydrogen peroxide as a propel-lant: hence catalytic channels are embedded internally in these devices. Consistent construction of these channels depends on a wide range of variables both in the design and fabrication of the channel structures. The primary focus of this paper is the characterization of final channel geometry when silver paste is applied to the upper and lower surfaces of an embedded single layer channel. Application of silver paste to the upper and lower channel surfaces has been shown to alter the final shape of the channels within the test structure. Upper and lower surface deflection into the channel area is discussed and characterization of this phenomena is illustrated as a function of channel width. A design of experiment (DOE) method is used to explore how process parameters affect the channel geometry/integrity. Construction of the test structures includes the use of pressure sensitive adhesives and a sacrificial material to maintain the overall channel geometry/integrity. Lamination and firing profiles are modified in order to enhance this construction methodology. Techniques used to produce and characterize these channels are discussed as well as the methods used to maintain channel geometry/integrity.