Formation of thin film resistors

Abstract

A method is provided for forming a patterned layer of resistive material in electrical contact with a layer of electrically conducting material. A three-layer structure is formed which comprises a metal conductive layer, an intermediate layer formed of material which is degradable by a chemical etchant, and a layer of resistive material of sufficient porosity such that the chemical etchant for said intermediate layer may seep through the resistive material and chemically degrade said intermediate layer so that the resistive material may be ablated from said conductive layer wherever the intermediate layer is chemically degraded. A patterned photoresist layer is formed on the resistive material layer. The resistive material layer is exposed to the chemical etchant for said intermediate layer so that the etchant seeps through the porous resistive material layer and degrades the intermediate layer. Then, portions of the resistive material layer are ablated away wherever the intermediate layer has been degraded.

Dependencies are inferred from the claim text.