A new high temperature multilayer capacitor with acrylate dielectrics

Polymer multilayer (PML) monolithic capacitors have been produced by a continuous high-speed vacuum process. The polymer dielectric is formulated by flash evaporating an acrylate monomer material onto a rotating drum and then cross-linking it by electron beam irradiation. The resulting polymer is thermally stable at temperatures in excess of 300°C. The dielectric films are pinhole-free and have stable electric properties. The capacitor electrodes are vapor-deposited aluminum and are thin enough to allow the capacitor to self-heal. The number of layers varies typically between 1000 and 5000 and the dielectric thickness between 0.3 and 1.0 μm. The low dielectric thickness results in capacitor chips with high volumetric efficiency that can be surface-mounted by conventional soldering techniques. An overview of the vacuum process, chip cutting, termination, packaging, electrical characteristics, and general test methodology is presented