Effect of Si-die dimensions on electromigration failure time of flip-chip solder joints

Abstract

Electromigration tests were performed for solder joints with various Si dies thickness and area. For the electro-migration in flip-chip solder joints with a 60, 100, 250 and 760 μm thick Si die, it is found that Si-die thickness has profound influence on electro-migration lifetime. The average failure time was 1608.0 h for joints with a 760-μm-thick die when they are stressed by 1.0 A at 100 °C. However, it decreased significantly to 0.6 h for joints with a 60-μm-thick die. According to the temperature measured by infrared microscopy, solder joints with a thinner die has a higher Joule heating effect, which results in a shorter electromigration lifetime. In addition, the die area has a considerable influence on the electromigration failure time. The electromigration failure time decreases as the die area decreases. The average failure time is 1608.0, 28.0, 10.6, 5.0 and 0.3 h for the solder joints with die area of 5350 × 4350 μm 2, 5350 × 3600 μm 2, 5350 × 3000 μm 2, 5350 × 2000 μm 2 and 5350 × 1000 μm 2, respectively. The Joule heating effect becomes more serious in smaller dies, which causes a shorter electromigration lifetime.