Effects of fluid properties on dispensing processes for electronics packaging

The fluid dispensing process has been widely employed in electronics packaging manufacturing to deliver fluid materials (such as epoxy, encapsulant, adhesive) on substrates or printed circuit boards (PCBs) for the purpose of die attachment, encapsulation, coating, or surface mounting. In this process, the fluid properties such as How behavior, surface tension, and contact angle can have a significant influence on the How rate of the fluid dispensed and the profile of fluid formed on the substrate or PCB, thereby affecting the quality of electronics packaging. At present, massive measurements are always required to characterize the fluid properties by using specific instruments, and the procedure of measuring is time-consuming. This paper presents a method upon which the fluid properties and their influence on the dispensing process can be readily identified from a few measurements of the process. By experiments, this method was proven to be not only cost and time effective but also promising for the investigation into the effects of fluid properties on the dispensing process.