Performance of evaporated and plated bumps on organic substrates

Hand-held consumer electronic products require low cost, small substrates. To increase substrate utilization, applications are being shifted from standard wire bond BGA to CSP and DCA, reducing substrate usage by up to 55%. To increase silicon efficiency, products are moving from perimeter to area array. The key interconnect enabler for FC-PBGA, CSP, and DCA applications is “the bump”: evaporated technologies, C4 (controlled collapse chip connection) and E-3 (extended eutectic evaporated), and electroplated and electroless plated bumps are reviewed briefly in this paper. The performance of each of these bumps is considered from the mechanical integrity and reliability points of view. The mechanical integrity of all of these bumps are evaluated by measuring the tensile strengths and by investigating their failure modes. Also, factors affecting the reliability of the bumps, such as the size and shape of the passivation opening, the under-bump metallization (UBM) thickness, and the bump height are evaluated on the eutectic electroless plated bump structure. Thereafter, the performances of C4 versus E-3 and C4 versus electroplated bumps are discussed. C4, E-3 and electroplated bumps have been found to be comparable to each other in terms of performance