ECR Plasma-Enhanced Au/Al Bondability in Fine-Pad-Pitch BGA Assembly

As the semiconductor IC process technology enters the deep-submicron or nano level, the pad area and space in bonding is gradually demanded to be shrunk. As a result, the smaller pad area and space, the worse bondability with the recent bonding technology. How to solve this challenge issue is an urgent task in assembly industry. In this paper, we propose an adequate plasma treatment to feasibly overcome this barrier in IC assembly concern. The plasma-enhanced chemical cleaning is employed to deterge the Al pads of IC products. Therefore, the surface pads exhibit the good clean efficiency and the micro roughness. Due to this application, the bondability performance in ball-grid-array (BGA) assembly experiment is obviously promoted. The reliability quality such as wire bonding strength, Al-Au eutectic ability, shear-pull force, and reduction of bonding parameters is effectively improved, too. Because of the good quality of surface pads, the ultrasonic output power and the bonding timing can be somewhat decreased to increase the throughput. In a short, the wafer crack probability and the pad oxide damage in bonding process can also be gradually deducted