PFAS-Free Underfill Material Evaluation for FCBGA Package

Per- and poly-fluoroalkyl substances (PFAS) are man-made chemical substances with high stability and persistence to prove Persistent Organic Pollutants (POPs). PFAS can exist in the environment for a long time and accumulate in humans to cause cancer. Due to the environmental impact and persistence of PFAS, more and more countries around the world are considering legislation to ban the use of PFAS. PF AS is widely used in the consumer and semiconductor industry. PFAS plays an important role in the semiconductor industry to banning PF AS will be a huge challenge. Following the requirements of environmental protection, most industries are also beginning to evaluate PFAS-free materials to meet these environmental requirements by implementing PF AS controls. PF AS is contained as a surface treatment agent in underfill materials for the assembly package. This paper discusses alternative materials and challenges for PF AS. Both the PFAS-free underfill and the PFAS-containing underfill material are analyzed the material properties by thermal analysis instruments such as Thermal Mechanical Analyzer (TMA) and Dynamic Mechanic Analyzer (DMA). In this paper, the fluidity test, shear strength, underfill void, fillet height/ width, and package warpage are evaluated to compare PFAS-containing underfill with PF AS-free underfill. The PF AS-free underfill can pass reliability. PF AS- free underfill is succussed to replace PF AS-containing underfill.