The process of flipchip bonding consists of forming conductive bumps/balls on the die bond pads and flipping the die to attach it to another silicon die or a substrate. The flipchip process creates a gap between the two dies or the die and the substrate. The gap is similar in height to the bumps/balls. Any mechanical shock, drop and vibration to the assembly would be experienced directly by the conductive bumps/balls which can either damage or break them off completely.
Underfill is the process of depositing an encapsulant in the gap between two dies or a die and the substrate to improve the reliability and durability of the flipchip assembly making both the physical contact and electrical interconnections more reliable.
The underfill encapsulation provides the following benefits to a flipchip assembly.
At the advanced packaging facility we can precisely and accurately deposit the underfill encapsulations for flipchip assembly. The facility has a robotic 3 axis jetting system with an integrated vision system which is ideally suited to the underfill applications.
At the facility we carefully consider the underfill requirements in terms of target applications of the flipchip assembly, the expected sources of failure and the required characteristics. The encapsulants are selected to match the specifications of the flipchip assembly based on its application. The jetting system allows us the flexibility to use either a one material underfill encapsulation or two material underfill encapsulation.