Electroless Plating – Its Applications in Resistor Technology

Abstract

Electroless processes for the deposition of metal films onto insulators have been known for many years. Various aspects of this technology have been applied in the field of resistor technology leading to improved performance of existing resistors and the evaluation of new resistors with novel characteristics.The applications of electroless nickel as a readily solderable, completely ohmic contact for tin oxide resistors is described.Copper oxide layers produced from oxidised electroless copper are shown to improve the thermal stability of tin oxide resistors.A range of electroless high precision metal film resistors from a fraction of an ohm to 100 kohm per square and from a few millimetres in length to over 1 metre is shown to be feasible. This technology has been applied to the manufacture of thin film circuits.The outstanding thermal stability of the electroless nickel-boron films and their temperature coefficient of resistance indicates a potential application in the field of temperature sensors.The ability to produce “weightless” films on Mylar sheet at 10 Gohm per square is considered to be a solution to the charge distribution requirement for electrostatic loudspeakers.