Patent ID: 6416635
Filing Date: 2002-07-09
Classification: C23C,H01J,H01L

Abstract:
A method of maintaining, from substrate to substrate, the uniformity, across the surface of a substrate, of a film sputtered from a relatively thick sputtering target that substantially erodes over its life, the method comprising the step of:sputtering, from a sputtering target of a given design, a film onto a plurality of substrates at each of a plurality of distances from the target and measuring the film thickness uniformity across the surfaces of the substrates; based on film thickness uniformity measurements, empirically deriving target-to-substrate spacing as a function of target erosion that will cause a film of a given uniformity to be sputtered onto a substrate from a target of the given design; sputtering, from a sputtering target of the given design, a film of the given thickness uniformity across the surface of a first substrate; then determining the state of erosion of the sputtering target; then changing target-to-substrate spacing in accordance with the empirically derived function; then sputtering a film of the given uniformity across the surface of a second substrate from the sputtering target.