Bumping Process Flow Introduction1Standard CSP Process FlowUBMWafer siliconPassivationFinal metalSputter two layer (Ti/Cu) UBMPattern the UBM pads and Cu platingFlux printing and ball placementBall reflow2PI+CSP process flowFinal metalPassivationPIWafer siliconCoating PI and patternSputter two layer (Ti/Cu) under bump metallizationPattern UBM and Cu platingPrinting flux and ball placementBall reflowSputter layer3RDL + CSP Process Flow1st PI and patternSputter two layer UBM (Ti/Cu) Pattern and Cu platingBall Placement and reflow2nd PI and pattern2nd PISputter two layer UBM(Ti/Cu) Pattern and Cu plating1st PIUBM/CuIncoming wafer inspectionFinal metalpassivationsilicon16542342Layer Cu Coil Structure(3P3M)silicon1st PIpassivation1st RepassivationSputter two layer UBM (Ti/Cu) Pattern and Cu plating2nd RepassivationSputter two layer UBM (Ti/Cu) Pattern and Cu plating3rd RepassivationSputter two layer UBM (Ti/Cu) Pattern and Cu platingPrinting flux and ball placement. ball placement5Gold Bump Process FlowAu platingIncoming waferFinal metalPassivationWafer siliconSputter two layer (TiW/Au ) under bump metallizationSputter layer6PI + Pillar Process FlowFinal metalPassivationPIWafer siliconSputter layerCoat PI and patternSputter UBM(under bump metallization)Plate Cu/SnReflow7