Contact resistance of the chip-on-glass bonded 48Sn-52In solder joint

Abstract

An average contact resistance of a COG joint bonded with 48Sn-52In solder was characterized using daisy chain structure. The average contact resistances of the 48Sn-52In solder joint of 29 μm diameter and 14μm height were 132mΩ/bump, 28.5 mΩ/bump, and 8.6 mΩ/bump on Ti(0.1 μm)/Cu(1.5 μm), Ti(0.1 μm)/Cu( 1.5 μm)/Au(0.1 μm), and Ti(0.1 μm)/Cu(3 μm)/Au(0.1 μm) UBMs, respectively. Such difference in the average contact resistance of the 48Sn-52In solder joint on each UBM could be attributed to partial oxidation of the Cu UBM layer during solder evaporation and a difference of the thickness of the Cu UBM layer remaining underneath the intermetallic compounds after soldering. ©2005 The Japan Institute of Metals.