Examination of Thin Film Uniformity at the Bottom of a Hole Structure Using a 3D Sputter Simulation Package

(Received 15 January 1996, received in final form 6 May 1996, accepted 28 May 1996)

Abstract
Sputter deposition onto substrates with large or complex surfaces is difficult as sputtering is a "line of sight" process. Sputtering into crevices or holes is particularly difficult if the electrical, optical or mechanical properties of the film sputtered in the "out of sight" region needs to meet tight specifications, as in the case of biomedical applications. The throw distance of a sputter system can be optimized by adjusting process chamber geometry or process parameters. Other techniques such as substrate rotation, substrate biasing or a high substrate temperature may assist in coating an awkward substrate uniformly. In this paper we use a 3D sputter simulation package to examine the uniformity of a film deposited at the bottom of a hole. We examine film thickness uniformity as a function of process pressure, racetrack geometry, and hole depth.