THIN-FILMS IN THE INTEGRATED-CIRCUIT INDUSTRY - REQUIREMENTS AND DEPOSITION METHODS

The requirements on the various thin films applied in advanced multimegabit integrated circuits (ICs) become more and more stringent. This is the main reason why the introduction of seemingly promising new films in the IC industry has been very slow or, in many cases, did not take place at all. The specific requirements relevant for films used in the IC industry are briefly summarized. As an example two aspects are treated in more detail: step coverage and nucleation. The physical-chemical processes controlling these phenomena are discussed. The relation between sticking coefficient, order of the chemical vapour deposition (CVD) reaction, surface mobility and step coverage is illustrated for a number of specific low pressure CVD and plasma-enhanced CVD films: W, Al, and SiO2. Further, it is shown that the initial nucleation of films such as polycrystalline Si and Si3N4 may be seriously inhibited. This has a negative impact on the film thickness and microroughness.