Metal-Containing Polymer-Based Composites for Resistor and Thermistor Applications

摘要

Embedding passive components into multilayer structures is one of the latest approaches of increasing "silicon" density on circuit boards. While embedded passive components made with thin film and ceramic thick film technologies have been developed, these are generally not applicable to polymer-based circuit board substrates. Consequently, polymer thick films, which are compatible with printed wiring boards, are being developed as an inexpensive path to integrated passive components. This paper introduces a novel approach to polymer-based resistor materials using a partially sintered metallic network instead of the particle-to-particle connections seen in typical carbon-filled resistor materials. By alloying to the copper pads the resistor material provides for a stable electrical junction, while the interpenetrating polymer provides adhesion to a variety of polymer and metal surfaces. The resistor material has been deposited by a number of different methods including stenciling, screen-printing, and filling of photo-patterned dielectrics. Test results obtained to data with these resistor materials on various substrates are presented. In order to demonstrate the feasibility of an embedded additive multilayer circuit board the photodefining technology was also used to pattern resistors, capacitors and conductive circuitry. Along with the resistor materials, which have a relatively low temperature coefficient of resistance (TCR), polymer-metal thermistor materials with a high TCR have also been developed.