Testing surface stability of passivated semiconductor elements - where temp.-stress tests are applied after contaminating passivated layer with sodium

摘要

The elements consist of chips or integrated circuits, and they are coated by a centrifuge process with a liq. (I) to form a film (Ia) with a prescribed thickness. Liq. (I) is obtd. by mixing a liq. silica film material with NaCl so the resulting soln. contains a prescribed amt. of Na atoms per cm3, and produces a film (Ia) of SiO2 doped with sodium. (I) pref. contains 1 x 1018 Na atoms/cm3, producing a film (Ia) with a thickness of 1000-4000 angstroms. Film (Ia) is pref. formed on the passivated surface layer (II) on the semiconductor element, so the resistance of layer (II) to Na can be measured in a temp./stress test. An accurate amt. of Na can be applied uniformly on the passivation (II) by a simple and inexpensive method which produces accurate results in the temp./stress test.