Film resistor and a method for forming and trimming a film resistor

Abstract

A thin film resistor (5) of an integrated circuit comprises an elongate resistive film (7) extending between electrical contact pads (10,11). A low impedance element (20) overlays and is electrically coupled to a portion of the resistive film (7) in an intermediate portion (22) thereof adjacent a second side edge (17) of the resistive film (7) for conducting current in parallel with the intermediate portion (22), and for reducing current density in the intermediate portion (22). First and second transverse edges (28,29) formed by spaced apart first and second slots (26,27) which extend from a first side edge (16) into the resistive film (7) define with a first side edge (16) of the resistive film (7) and the low impedance element (20) first and second trimmable areas (30,31) in the intermediate portion (22). Coarse trimming of the thin film resistor (5) is carried out by progressively extending a first trimming slot (34) into the first trimmable area (30) from the first transverse edge (28), and fine trimming is carried out by extending a second trimming slot (35) into the second trimmable area (31) from the second transverse edge (29).

Dependencies are inferred from the claim text.