Product Briefing Outline: KLA-Tencor has extended its product offerings in the CMOS image sensor (CIS) market by announcing the 8900 defect inspection system. The system offers selectable illumination wavelengths, color-matched to CIS pixels; simultaneous brightfield and darkfield optical channels to enable capture of a wide variety of defect types; and adjustable sensitivity and throughput settings for cost-effective defect management from initial product development through volume production of color filter arrays (CFA). An 8900 defect inspection system was recently installed at the first 300mm advanced CFA fab of Toppan Printing.
Problem: Image sensors are devices that convert light into electrical signal, for use primarily in cameras. A color filter allows each pixel of the sensor to respond to a specific color—typically red, green or blue (RGB). The CFA is constructed in single-color, patterned layers, with one filter on top of each sensor pixel. Each pixel is capped with a micro-lens. Image sensor fabs have been using a combination of defect inspection systems, including manual inspection, to cover CFA process development, line monitoring, and incoming and outgoing quality control. Even with automated systems, critical defect excursions can be missed because the results are difficult to compare among different systems. As yield-limiting defects can occur at any step in the assembly process, the 8900's ability to inspect any of the filter or micro-lens layers can help reduce materials waste and cycle time.
Solution: In developing the 8900, KLA-Tencor leveraged its extensive experience in brightfield and darkfield micro and macro inspection to provide image sensor fabs with a single, flexible system to address the breadth of their CFA inspection requirements. The 8900 will allow fabs to improve resource allocation, increase the yield of their current products and accelerate delivery of their latest image sensors.
Applications: CMOS image sensors. Simultaneous brightfield and darkfield optical paths capture a wide range of defect types in a single pass, such as micro-lens deformation; resist and fall-on defects; color contamination; large stains and striations.
Platform: Selectable LED inspection and review illumination spectrum matched to CIS filter colors. Sensitivity consistent with requirements of advanced CIS roadmaps. Throughput above 110 wafers per hour at production sensitivity, for 300mm semiconductor wafers. Automated binning of defects by type. Automated sensor pass/fail dispositioning and Automated color review for defect verification.
Availability: October 2009 onwards.