Material Characterization and Failure Analysis for Microelectronics Assembly Processes

Abstract

In recent decades, the electronic industry has shown a clear trend towards miniaturization with increasing functionality. In the context of essential competition within the market, the reliability of long term operations has become a popular issue. This study examines the properties of printed circuit board (PCB) and its failure phenomena. PCB reliability is characterized through verifications taken from various process conditions. Notably, results can be used as selection criteria for PCB materials, helping to reduce PCB delamination during the assembly process. In addition, surface finish is a key factor seen to affect a product’s durability, as the microstructure between solder and the metallized layer varies between surface finish types and has been shown to affect overall solder joint strength. Notably, the black pad phenomenon will reduce the strength of solder joint significantly and affect product’s durability. Characterization of failures and materials related to chemical and soldering processes used in microelectronics assembly are also discussed in this study. Analytical techniques used for chemical structures, compositions, and soldering properties including Fourier transform infrared spectrometer (FTIR), scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX), and dye staining are conducted. The jumper pillow speaker connector (JPSPK) connector pins show an obvious difference in color between the clean and contaminated areas. The contaminants on the connector pin were identified as the flux used in the assembly processes following a comparison of the FTIR spectra database. Additionally, the incoming plastic housings showed different bright and dark surfaces whose chemical structures were shown to be polycarbonate (PC) and acrylic ester, respectively. It indicates that varied surface treatments for the incoming housings. To determine whether any cracks in the solder joints occurred in the CPU BGAs, a dye staining analysis was carried out. The crack size percentage is classified according to the crack’s (dyed) area. The establishment of the infrared spectra database for fluxes and