Interconnect Methods for Chip-on-Board Assembly (COB) (1) GOLD-BALL BOND PROS: high throughput, high strength, omni-directional, fine pitch CONS: elevated temperature, increased material cost, intermetallic corrosion potential ISSUES: temperature, power, force, time, wire diameter, wire length, metallurgy, pitch, bonding surface conditions, bonding area (2) ALUMINUM WEDGE BOND PROS: room temperature processing, lower material cost (wire), fine pitch CONS: Strength, throughput, not optimum for non-hermitic applications ISSUES: power, force, time, wire diameter, wire length, metallurgy, pitch, bond angle, forward/reverse bonding, bonding surface conditions, bonding area (3) FLIP CHIP EUTECTIC SOLDER PROS: electrical performance, smallest footprint, reworkable, reliability CONS: underfill, high density PWB required, infrastructure ISSUES: reflow profile, underfill approach, placement accuracy, bump/UBM metallurgy, substrate design and materials, CTE, thermal hierarchy Seal & Encapsulation DIE & WAFER MEMORY SPECIALISTS Copyright 2000-2008 Die Delivery and Services