Fault localization and analysis in semiconductor devices with optical-feedback infrared confocal microscopy.

Area of Science:

• Semiconductor device characterization
• Optical microscopy techniques
• Integrated circuit analysis

Background:

• Characterizing semiconductor devices requires precise methods to identify functional and defective sites.
• Existing techniques may be limited by background noise or resolution.
• Optical beam-induced current (OBIC) is often used but can be hindered by bandgap energy limitations.

Purpose of the Study:

• To develop a cost-effective optical setup for characterizing light-emitting semiconductor devices.
• To accurately differentiate functional and defective sites in integrated circuits.
• To isolate surface-emitting p-i-n devices without strong OBIC background.

Main Methods:

• Utilizing optical-feedback confocal infrared microscopy.
• Employing optical beam-induced resistance change with an infrared laser diode.
• Scanning the integrated circuit (IC) across the focused beam to map current variations.
• Simultaneously acquiring confocal reflectance images for high-resolution referencing.

Main Results:

• High-contrast current maps were generated, enabling accurate differentiation of functional and defective sites.
• Surface-emitting p-i-n devices were successfully isolated.
• Inhomogeneous current distributions were visualized without OBIC background at diffraction-limited resolution.
• Accurate identification of metal and semiconductor sites and classification of metallic structures were achieved.

Conclusions:

• The developed technique offers a cost-effective and high-resolution method for semiconductor device characterization.
• It effectively overcomes limitations associated with OBIC by using thermal resistance changes.
• The approach allows for detailed analysis of ICs, including metallic structure properties.