Direct-Write Thermal Spraying of Multilayer Electronics and Sensor Structures

Direct write methods provide an efficient and environmentally conscious means of additive fabrication of electronic multilayers on conformal substrates. Thermal spraying is a method for additive fabrication of multilayers through direct write approaches. This technique offers promise in the area of direct write conformal electronics, sensors, and sensor array concepts. This chapter reviews preliminary assessment of the technology, materials, and various application concepts. Thermal spray is a directed spray process, in which material, generally in molten form, is accelerated to high velocities, impinging upon a substrate, where a dense and strongly adhered deposit is formed by rapid solidification. Material is injected in the form of a powder, wire, or rod into a high velocity combustion or thermal plasma flame, which imparts thermal and kinetic energy to the particles. Components ranging from insulated substrates, capacitors, conductors, resistors, to inductors and sensors, can be fabricated using a group of established and novel thermal spray processes.