Optimizing Source Location For Control of Thickness Uniformity
For a substrate rack in single rotation it is theoretically possible to achieve perfect thickness uniformity simply by developing the correct mask profile for the emission characteristic of the evaporation source. In practice this is quite difficult to accomplish – particularly for large diameter substrates – because the mask will only impose a perfect correction for a unique source characteristic. The source behaviour can vary over time, from run to run and from one material to another. In this paper we show that theoretical modeling can lead to a chamber layout which is less sensitive to such variations in source behaviour and therefore should result in more consistent thickness uniformity.
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