CNT- lead free solder composite electrodeposition for obtaining high speed interconnect for memsapplication

Today's high functionality electronic circuits require faster interconnection speed, better thermal conductivity and the good mechanical properties for reliability. These requirements calls for enhanced properties of the present solder materials. Appropriate reinforcements in the existing solder material will help in achieving much improved electrical, mechanical and thermal properties. Carbon Nano Tubes (CNTs) are one such material that can bring in considerable improvements in the properties of the solder material. CNT-Solder composite with less than 1% CNT is being explored for solder bumps in flip chip applications. This paper reports our work on co-deposition of CNT along with lead-free solder using electroplating process. For co-deposition of CNTs along with the solder, the processing of CNT is very important. Milling and CNT functionalisation are two such parameters that aid in its dispersion and make it active. The present studies include optimization of milling time for CNTs and selection of appropriate activators for functionalisation of CNTs in the electroplating bath.