GB1103653A - Method and apparatus for sputtering - Google Patents

Abstract

In a sputtering process of depositing a material on a substrate a radio frequency electric field is established between a pair of sputtering electrodes in a low-pressure atmosphere, the field being such as to form a plasma between the electrodes. The material is sputtered from both electrodes which may be of the same or different material and the coating layer may be formed of a single material, layers of different material, a composite consisting of a mixture of the different material from both electrodes or as a graded layer varying in composition from the material of the first to the material of the second electrode. The sputtered materials may be Cu, glass, quartz, porcelain, BeO, permalloy; the substrates specified are conductors, insulators and semi-conductors such as Si and glass. The sputtering is carried out at 10-6 to 10-3 Torr and the sputtering atmospher may be inert e.g. argon, or reactive e.g. oxygen or nitrogen which would result in the formation of metal oxides or nitrides. The frequency of the applied RF field is 1-100 megacycles/sec. A baffle or shield may be located in the sputtering chamber and may be moved so as to obstruct the sputtering from one of the electrodes. Alternatively the shield may be located within the Langmuir sheath zone of an electrode (within 1/2" of electrode surface) and is then itself sputtered to form part of the coating. The specific examples relate to coating a Si wafer with glass; a Si wafer with a layer of glass, a layer of Cu and a further layer of glass; by using a permalloy shield a Si wafer is coated with glass/copper/permalloy/glass.