Problem: Historically, wafer-edge defectivity has been primarily physical in nature, such as chips or cracks. With the transition to 300mm production and sub-90nm design rules, demanding process integration challenges due to increased device and stack complexity have given rise to a new class of edge-related defects. For example, residue from chemical mechanical planarization (CMP) or etch processes can create interfacial stresses or poor adhesions of film layers, which in turn lead to blister defects or peeling. These defects can then migrate onto patterned areas during subsequent processing and cause significant yield losses or transfer to process tools resulting in long tool downtimes. The use of wet chemistries in advanced wafer processing, such as in immersion lithography, can compound this problem.

Solution: VisEdge CV300 offers complete wafer-edge scanning and capture of both macro- and micro-based defects with high sensitivity. Unlike traditional edge-inspection systems, its simultaneous multi-channel signal acquisition technology combines four detection methods (scatterometry, reflectometry, phase shift and optical beam deflection) to achieve greater accuracy and purity in capturing defect sources that cause a variety of problems, including small particles, stains and film delamination, while eliminating the need for repeat scans. Advanced rules-based defect classification software with robust signal enhancement and smart filtering routines is claimed to eliminate edge background noise -- a problem worsened by the severe topography at the wafer's edge that impairs the detection capabilities of other inspection techniques -- to highlight defects of interest and enable fast identification of defect types.

Applications: 300mm wafer edge inspection for volume production environments

Platform: VisEdge CV300's combines four detection methods (scatterometry, reflectometry, phase shift and optical beam deflection)

Availability: KLA-Tencor will begin shipping in the1Q07.