New Developments in Polymer Thick Film Resistor Technology

摘要

Motorola has been using embedded polymer thick film resistors on immersion silver-plated copper terminations in productsrnfor four years, and in the past year other firms have begun using this technology in their products. It is available to anyrnelectronic equipment maker from multiple board suppliers. Highly reliable resistors with values ranging from ohms to megaohmsrncan be embedded in conventional HDI/FR-4 multilayer boards, providing cost savings and product size reduction. Inrnthis paper we present recent improvements in resistor materials and design. Resistor value predictability is improved with arnsimple innovation in termination design and the segmenting of low aspect ratio resistors. Resistor value distributions arernimproved with more thixotropic inks. Combined, these improvements allow 10-20% untrimmed tolerances (depending on inkrnresistance and production volume) for 0.25-mm-wide resistors. Tighter tolerances are possible with laser trimming.