Compound semiconductors play a key role in innovative fields and in sectors with a promising future, such as telecommunication, energy, automotive, transport, aerospace or consumer electronics. Combinations of materials, such as SiC (silicon carbide), GaN (gallium nitride) or GaAs (gallium arsenide) are – in comparison with silicon – superior with regard to their thermal, optical and electrical properties and therefore improve the performance of new devices.
Compound semiconductors require specific inspection and metrology solutions
As a result of the numerous material combinations possible, the production process of compound wafers is challenging and requires specific inspection and metrology solutions (automated optical inspection – AOI). The Confovis WAFERinspect AOI allows the fast and flexible inspection of epitaxial layers, the measurement of the surface topography and of stress cracks and facilitates step measurements, bow measurements etc.
Irrespective of the contrast of the surface, the Confovis WAFERinspect AOI with its realtime control keeps the compound semiconductor’s structure in focus which is to be inspected. This makes it possible to use objective lenses with a high numerical aperture (NA), in or-der to benefit from the maximum lateral resolution of light-optical inspection systems.
Why Confovis for the inspection of compound semiconductors?
Compound semiconductors – Measurement tasks
- Macro defects
- Micro defects
- Particle inspection
- Golden Sample
- Defect detection with AI (deep learning, anomaly detection)
- Feature-based defect classification with neural network
- Independent of materials: silicon, epoxy, glass, chrome, resist, etc.
- Measurements of demanding surfaces without artifacts (no ‘bat wings)
- High speed: 60 confocal frames per second (250 mil. measuring points)
- Film Thickness / Layer Stack
- Step Height
- Oblong holes
Compound semiconductor applications
A universal tool for the inspection of compound semiconductors
The measurements are made with an accuracy of 3 nm and a repeat accuracy of 2 nm @ 3 Sigma (example of a 50 nm step certified by the Physikalisch Technische Bundesanstalt [German national test authority]). Angles, distances, radii etc. can also be precisely measured. The data are transmitted to the host via SECS/GEM.
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