Low-Stress Resin Encapsulants for Semiconductor Devices

An innovative low-stress epoxy encapsulant was developed for large and stress-sensitive devices by the utilization of silicone modification technology. The characteristics can be explained by achieving a lower Young's modulus and thermal expansion coefficient. The low-stress level was confirmed by piezo-resistance measurement with actual results showing a definite, significant improvement against package and passivation cracks. An interesting microstructure of the new material was determined and labeled "Sea-Island" structures.