Three Dimensional Vertical Integration Technology Based on Thermal Ultrasonic Bonding Method

Three dimensional vertical integration technology is becoming more and more attractive for realizing the miniaturization, lightweighting and high density integration of electric information system. In this paper, the thermal ultrasonic bonding method with Au-stud bumps to the 3D vertical stacking of multiple interposers is introduced. Through the pre-flatting technology, Au-stud bumps with much more uniformity is fabricated. By setting reasonable ultrasonic amplitude, pressure and temperature parameters,and optimizing the timing of the matching ultrasonic curve and pressure curve, the bottom up high precision, high reliability stack of the silicon adapter board is achieved, the problem of solder slippage is solved. The thermal ultrasonic bonding technology with Au-stud bumps offers the best solution for 3D vertical integration, which avoids the multi-layer stacking without consideration of the welding temperature gradient and can deal with various types of pad systems without the need for the preparation of special UBM layers, it can be widely used in 3D integrated system packaging technology.