Feb 25 2003
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Advanced surface analysis techniques play a major and continuous role in assisting semiconductor device engineers to achieve goals like those mentioned below.
Methods like X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) are two highly sensitive surface analysis tools that offer a considerable amount of data about the surfaces of materials and devices. This helps manufacturers to resolve existing processes, and expand research and development efforts.
Benefits of Using Surface Analysis
In the current semiconductor sector, the most significant targets for device fabrication are:
- Yield improvement
- Higher throughput
- Higher performance
- Enhanced device reliability
Case Study: Surface Staining on Device Wafers
This case study demonstrates the characterization of a green surface stain present on the opposite side of a failed device wafer, using the XPS and ToF-SIMS techniques.
Time-of-Flight Secondary Ion Mass Spectroscopy Findings
ToF-SIMS spectra of both stain and non-stain areas display the presence of organic residues, silicon oxide, aluminum, sodium, chlorine, and fluorine.
The comparative levels of contaminants are similar in both areas.
Moreover, high-resolution XPS of the Si 2p spectral region reveals that the stained area contains considerably higher levels of silicon oxide.
X-Ray Photoelectron Spectroscopy (XPS) Findings
XPS analysis showed similar levels of N, C, and Al in both stain and non-stain areas.
Summary
The combination of XPS and ToF-SIMS techniques shows the higher levels of silicon oxide in the stain region. Detection of a defective process step eliminated the problem, with further yield improvement.