Novel Approach To Resolve Strip Camber At Assembly Process Of Semiconductor Packaging

Effect of strip camber in micrometer scale used to pose no risk or challenge to the back-end assembly process of semiconductor packaging. However, with the advancement of semiconductor technology, the assembly process is driving the devices to become smaller and smaller in size. Thus, a minor alteration in the substrate strip condition will pose great quality risk to the product, as the tolerance range of acceptance is greatly reduced when product miniaturization occurred. One of the most impacted processes in backend assembly is the product’s singulation to separate bulk processed products into individual unit. Due to this reason, the current work aims to provide state of the art approach to resolve strip camber at backend assembly process through experimental investigation. This paper presents comprehensive study on the backend assembly process that induce strip camber. Based on the data collected, the leading contributing process towards the magnitude of strip camber was observed at molding process. Design of experiment (DOE) methods was deployed to study the key parameters influencing the camber effect. The results show that the lower the HFC (high floating chase) of 1
^st
and 2
^nd
clamping force in molding process, the lower the magnitude of strip camber observed. While the higher the packing pressure, the lower the strip camber effect was observed. In addition, the current study also compares the performance of conventional straight cutting method with novel partial cutting method at package singulation process. The data obtained shows that average Cpk enhancement of 54.67% was obtained by utilizing partial cut method in comparison to conventional straight cut method when cutting cambered strip. This shows that the partial cut method is capable of cutting substrate or strip having the camber effect.