Contamination is the present of impurity / un-wanted substance in a material that affect the manufacturing process and the quality of the final product. Material Analysis on these contamination is essential to help locate the contamination and identify the constituent of the contamination. Once we? identify the composition of the contamination, we may able to draw clues to the origin of the contamination and preventive/corrective measures can also be made to toggle the problem.
Depends on the type of contaminants (organic or inorganic), the amount of impurity (large, little amount or in ppm level), the location (at the surface, at the interface or bulk) and distribution (evenly distributed or localized), different detection devices can be used to identify the constituent present in the contaminants, residues, wear debris, oil and etc.
- SEM (scanning electron microscope)/ EDS (Energy Dispersive Spectroscopy)
- XPS (X-ray Photo-electron Spectroscopy )
- AES (Auger Electron Spectroscopy)
- FT-IR(Micro Fourier Transform Infrared Spectroscopy)
- TOF-SIMS
- ICP-AES
Common Applications
- Plating and Metal Finishing
- Electronics
- Connectors
Examples
A. Bonding failure in PWB
Analysis Technique: XPS
Figure 12 XPS spectrum of normal pad
Figure 13 XPS spectrum of poor bonding pad (detection of Ca & Mg)
Figure 14 XPS C1s detail analysis on the poor bonding pad showed carbonate contamination.
B. Orgainc contamination on the contact surface of switch
Analysis Technique: FTIR
Figure 15 FTIR spectra of the contact surface of the switch and the reference.
C. Wetting failure in PWB
Analysis Technique: SEM/EDX
Figure 16 SEM image of the copper pad with poor wetting
Figure 17 EDX spectrum of the poor wetting copper pad showing contamination of solder mask (i.e., presence of Ba)
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