Undetected Pressure Variations in Flip Chip Assembly Reduce Yields and Raise Costs

Undetected bonding pressure variations can result in poor or open flip chip connections, reducing yield and long-term reliability while raising costs. Maintaining a uniform distribution of bonding pressure across a flip chip die assures chip to substrate coplanarity, optimal bump compression, and a controlled, reproducible die to substrate gap. Pressurex pressure indicating sensor film is a valuable assist to today’s flip chip bonders which lack the capability to measure pressure variations across the bonding tool but instead rely on average pressure with the assumption that it is uniformly distributed. Now a proven control measure in wafer-to-wafer bonding, Pressurex could extend similar low-cost coplanarity and uniformity control to flip chip bonding.