IMMERSION TIN SILVER PLATING IN ELECTRONICS MANUFACTURE

摘要

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.