Abstract
This paper discusses deposition parameter effects and subsequent heating on certain properties of sputtered Al‐4 a/o Cu‐1 a/o Si films. Emphasis was placed on developing a process yielding metal films resistant to hillock growth during the deposition of passivating films in a plasma‐enhanced chemical vapor deposition (PECVD) reactor at relatively high (400°C) temperatures. The films were made in a commercial sputtering system which did not provide a means to heat sink the Si substrates. In contrast to most earlier reports, film smoothness and morphological stability increased with decreasing substrate deposition temperatures. Films deposited onto substrates pre‐heated to ∼200°C increased their average roughness from ∼25 to ∼320 Å during the PECVD process, resulting in hillock heights up to 5000 Å. By contrast, films deposited onto non pre‐heated substrates underwent a roughness increase from ∼20 to ∼80 Å with PECVD processing to yield maximum hillock heights of ∼500 Å. This difference is attributed to substrate heating by the deposition process and the absence of heat sinking which leads to an estimated 150–200°C increase in effective deposition temperature above the nominal values; such films, when re‐heated to 400°C, lack sufficient compressive stresses to produce large hillocks. Reductions in both grain size and preferred orientation were also found to enhance film stability.