Texas Instruments Incorporated
IC WITH MATCHED THIN FILM RESISTORS

Abstract:

A method of fabricating an integrated circuit (IC) includes forming a dielectric layer on a substrate having a plurality of the IC. A thin-film resistor (TFR) layer is deposited on the dielectric layer, and an underlayer (UL) including carbon is formed on the TFR layer. A hard mask layer including silicon is formed on the UL. Masked etching of the hard mask layer transfers a pattern of a photoresist layer onto the hard mask layer to form a hard mask layer pattern. Masked etching of the UL transfers the hard mask layer pattern onto the UL to form a UL pattern. Masked etching of the TFR layer transfers the UL pattern onto the TFR layer to form a TFR layer pattern including a matched pair of TFRs. The matched pair of TFRs are generally included in circuitry configured together for implementing at least one function.