Wafer Inspection

Short-Wave Infrared (SWIR) imaging provides a powerful, non-invasive method for wafer alignment and failure analysis in semiconductor manufacturing. Materials like silicon and gallium arsenide are transparent to SWIR wavelengths due to their molecular bandgap properties, which absorb higher-energy visible and near-infrared light but allow lower-energy SWIR light to pass through. This makes imaging through semiconductor wafers and integrated circuit die highly effective using InGaAs cameras developed by Sensors Unlimited.

Integrated circuit manufacturers use these cameras to inspect the quality of semiconductor crystals following epitaxial growth into ingots or boules. As the wafers are sliced and processed into multiple layers for constructing transistors and memory cells, SWIR cameras facilitate precise layer alignment. High-resolution scans for internal defects or cracks are performed using InGaAs line scan cameras during the wafer defect inspection stage.

Following full circuit fabrication, SWIR cameras play a vital role in identifying faults. Photon-counting avalanche photodiodes (APDs) detect weak photonic emissions from malfunctioning components, which cooled InGaAs cameras then image through the backside of the device to locate defects at specific circuit layers. This approach is particularly effective during microscope inspections on wafer probe stations.

Additionally, SWIR imaging supports the fabrication of Micro-Electro-Mechanical Systems (MEMS) and silicon optical waveguides. Engineers inspect micro-machined features and assess optical waveguide performance, identifying beam property issues and leakage with high precision. Sensors Unlimited’s SWIR imaging systems offer a complete solution for semiconductor inspection, layer alignment, and failure localization, enhancing yield, efficiency, and quality control in microelectronics manufacturing.