Next Gen Laser Assisted Bonding (LAB) Technology

Abstract

There are several chip to substrate interconnection technologies in the packaging tool kit such as mass reflow (MR), thermocompression bonding (TCB) and laser assisted bonding (LAB). MR is a mature process but has known limitations on fine pitch devices and large/thin substrate packages. TCB has the advantage to minimize bump stress for low-K dielectric devices but its productiviy is very low. However, LAB can provide a solution for advanced devices with its localized heating and short bonding time. Recently, demand for fine-pitch Flip Chip bumps and large/thin substrate packages has increased, resulting in industry interest in LAB due to its good quality and high productivity.Amkor Technology invented LAB technology in 2014 and passed qualification for multiple devices from customers through many years of development and has been in high volume production for major customers since 2018.However, as the industry continues to require high bonding performance with various new devices, existing LAB technology may not support all these applications. These devices have led to the development of Next Gen LAB technology with a new bonding concept. One of devices that requires Next Gen LAB will be back side metallization (BSM) dies. BSM dies are necessary for Metal thermal interface material (TIM) applications for high thermal performance packages.In this study, new LAB technology is introduced, and its performance is compared with existing LAB with BSM die bump using large body FCBGA package. We focused on infrared (IR) temperature, X-ray inspection and cross-sectional anaysis to verify bump interconnection quality. Good bump quality was achieved with Next Gen LAB technology. This allows it to be another solution for next generation devices in the near future.