Problem: The ability to look closely at the wafer edge is becoming more crucial at the 90nm technology node and below, especially as SEMI now has new standards for wafer edge quality.  Problems with wafer breakage during IC processing can be attributed to structural defects in the edge of the underlying wafers.  The digital imaging technique used by the BedeScan allows IC and wafer manufacturers to look closely inside the wafer at buried defects, instead of just on its surface (as with traditional film inspection methods) to reveal damage which has probably been incurred during wafer handling. 

Solution: The BedeScan has a variety of applications including sensitivity to dislocations, precipitates, mechanically introduced cracks, and inclusions at any depth within the wafer.  The system monitors pin marks, thermal slip dislocations, misfit dislocations, back-side and front-side scratches, surface and buried mechanical edge damage, precipitates, inclusions and overall lattice parameter and strain variations. The BedeScan is also used as an edge inspection system, able to detect and characterize strain induced by wafer handling, which can lead to edge die yield loss or wafer breakage. In whole wafer inspection mode, the system is able to detect and characterize backside wafer defects before they develop into micro cracks.  Cracks can become particle generation centers affecting the yield of neighboring wafers during batch processing.

Applications: Crystallographic abnormalities inside the wafer and edge exclusion zone monitoring.

Platform: Bede is currently working on developing the next generation BedeScan, a fab-ready and fully automated tool conforming to industry standards.  This dual mode system will provide scans of the edge exclusion zone in a revolutionarily fast time, according to the company and also detailed X-Ray Diffraction Inspection maps of the critical areas once potential defects are found.

Availability: April 2006 onwards.