Enhancement Of Plating Uniformity Of IC Packaging Substrate Based On VCP Line And Minitab Softerware

IC packaging substrate is used for connecting chip with printed circuit board, thecopper uniformity of which could directly influence the reliability during packaging IC.The uniformity of plating copper and pillar was studied on the plating processes.The substrate with whole copper plating in VCP line was investigated based onMinitab Software. The resin in substrate was analyzed via infrared spectrometricanalyzer and coarsened by alkaline permanganate solution for10min~15min at thetemperature ranging from50℃~70℃. Good surface roughness was obtained aftercoarsening. The coursing substrate was sputtered with tiny copper particles and thenwas plated in VCP line. Electro-deposition copper atoms grew up quickly afteradsorbing in many dimensions of tiny copper particles so that the surface of copperplating layer showed as uniformity and smoothness. The uniformity quality of copperplating could be enhanced as Cpk at1.88after the analysis of Minitab Software whilethe fixture shielder was controlled with sealing holes and raising the bottom shieldingarea. New dummy boards as the first plating board could ensure the uniformity forcontinuous plating process.The technology parameters as current density, plating time and solutiontemperature were studied based on the analysis method of uniform design. Therelationships of current density and solution temperature to the quality of plating copperwere discussed. The regression nonlinear equation between technology parameters andplating copper thickness was fitted by Minitab Software.The stability and uniformity of copper pillar were also analyzed by MinitabSoftware. One failure problem as leak plating could be dealt with closing and sealingpipeline for air agitation. Another failure problem as crack between copper platinglayers could be solved by adding shocking and water-spray cleaning equipments withjet-flow rate at15m3/h. The shielding fixture was used for plating copper pillar (80μm)in order to enhance the quality of uniformity. Copper pillar array with thickness at26μm±6μm could be well manufactured and had good agreement with the requirementof uniformity. Continuous plating monitoring system was developed to meet with platingequipment. Based on theconclusions of plating uniformity, IC packaging substrate wasmanufactured under plating monitoring system. The copper plating layer and pillar hadgood agreement with the uniformity requirement of IC chip. The line at25μm could bewell manufactured to meet with the requirement of fine line due to the uniformity ofcopper plating layer.