Methods of depositing metals by evaporation

摘要

934,408. Coating by vapour deposition. INTERNATIONAL BUSINESS MACHINES CORPORATION. Sept. 29, 1959 [Dec. 29, 1958], No. 33042/59. Class 82. In a process for vapour depositing a metal such as tin, a mixture of the coating metal and a reducing metal such as tantalum, tungsten or molybdenum is heated under vacuum to a first temperature at which the reducing metal forms volatile compounds such as oxides with the impurities in the coating metal and after evaporation of these volatile compounds the temperature is increased to evaporate the coating metal. As shown in the drawing, tin powder 1 and a reducing metal coil or strip 3 of tantalum, tungsten or molybdenum is supported in a graphite crucible 2 in a vacuum chamber 18. The crucible is heated via watercooled electrodes 8 and 9 and is surrounded by a water-cooled copper shield 12. A substrate 15 is positioned above the evaporation source and an adjustable masking shutter 28 operated by knob 29 via shaft 30 is positioned between the substrate and the evaporation source. The apparatus is evacuated to 10-5 to 10-7 mms. Hg and in the first stage the temperature of the metals is raised to 1200‹ C. when a volatile oxide of tantalum, tungsten or molybdenum is evaporated and deposited on the shutter 28. The shutter is then rotated to expose the substrate 15, the temperature is increased to 1600‹ C. and tin is then evaporated and deposited on the substrate. Specification 862,178 is referred to.