IMMERSION TIN SILVER PLATING IN ELECTRONICS MANUFACTURE

• Main Authors: WANG, Xingping, WENGENROTH, Karl, F, WANG, Cai, KUDRAK, Edward, J., Jr, ABYS, Joseph, A, FARRELL, Robert, YE, Pingping, YAU, Yung-Herng
• Format: Patent
• Language: English; French; German
• Published: 05.12.2018
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

A method is provided for depositing a whisker resistant tin-based coating layer on a surface of a copper substrate. The method is useful for preparing an article comprising a copper substrate having a surface; and a tin-based coating layer on the surface of the substrate, wherein the tin-based coating layer has a thickness between 0.5 micrometers and 1.5 micrometers and has a resistance to formation of copper-tin intermetallics, wherein said resistance to formation of copper-tin intermetallics is characterized in that, upon exposure of the article to at least seven heating and cooling cycles in which each cycle comprises subjecting the article to a temperature of at least 217° C. followed by cooling to a temperature between about 20° C. and about 28° C., there remains a region of the tin coating layer that is free of copper that is at least 0.25 micrometers thick.