Symposium Conference Proceedings

The Use of MICRO/ATR FTIR in PCBA CRD Smearing Failure Analysis

Authors: Lee Kong Hui and Jason Ho Wye Meng
Company: Cisco Systems (Malaysia) Sdn. Bhd.
Date Published: 4/8/2014   Conference: Symposium

Abstract: Fourier Transform Infra-Red (FTIR) Spectroscopy is a powerful tool that is frequently used in the Surface Mount Technology (SMT) failure analysis process to identify various chemical contaminants and their properties. Due to different sample preparation methods and detection approaches, Micro FTIR Spectroscopy and Diamond Attenuated Total Reflectance (ATR mode) FTIR analyses were used in the identification of flux Chemistry and Printed Circuit Board Assembly (PCBA) processes on the properties of marking ink during the failure analysis of smearing defect encountered after wave soldering process of component reference designators (CRD). Infrared spectral detection was captured in the range of 4000 to 650 wavenumbers (cm-1) for both Micro and ATR FTIR analyses.

The case study presented here depicts that white notation ink for a few failing PCBAs were not properly cured during their manufacturing processes. Detailed comparison among the various samples FTIR foot print have further indicated that the improperly cured notation ink functional groups may have evolved and changed into other properties during wave soldering process. Matching rate of 95.26% FTIR foot print between the raw and wave soldered ink sample has confirmed fully cured marking ink properties, while a low matching rate of 33.97% for the failing PCBA sample is deducing improperly cured condition.

Key Words: 

FTIR, Failure Analysis, PCBA, CRD Smearing, Wave Soldering Process

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