Development of scanning acoustic microscopy method with passive integration package for mass production monitoring

Abstract

Scanning Acoustic Microscopy (SAM) is a nondestructive method to investigate delamination in packages. However, increasing of integrated function and new material applied into package had posted some challenges in SAM surveillance and analysis. Integration of passive component in moulded packaging has contributed to more complicated analysis for package delamination inspection. Furthermore, introducing of high silver filler die attach material into moulded packaging for passive component bonding have leading confusion on the SAM results interpretation as compare to the usual practice. The new “moon shape” delamination signal observed with white colour contrast normally will be interpreted as a delamination defect under normal SAM image interpretation. However, further cross section analysis and coupled with FIB cut has confirmed that the delamination defect is not genuine. This phenomenon is causing some confusion for operator to differential the real defect sample as compare to the standard production packages. In order to clear the confusion as observed, new sample preparation methodology and scanning apparatus has been introduce for delamination results verification. Pre-sample preparation by partially removing the package backside mould compound had improved the SAM image clarity for easy interpretation. Further experiment with high frequency and short focal length transducers scanning have successfully clear the doubt as observe earlier. The details of the scanning methodology and apparatus applied will be describing details in this paper.