MILPITAS, USA: KLA-Tencor Corp., the leading supplier of process control and yield management solutions for the semiconductor and related industries, announced the latest addition to its industry-leading VisEdge family of products: the VisEdge CV300R-EP edge metrology and inspection tool.
The VisEdge CV300R-EP introduces two edge-metrology capabilities designed to help fabs identify potentially yield-impacting irregularities in the shape of the wafer edge profile or in the edges of films deposited on the wafer.
These new metrology capabilities add to the edge defect inspection and review capabilities of current VisEdge systems, making the VisEdge CV300R-EP a comprehensive tool for helping fabs improve yield issues associated with the wafer edge.
Semiconductor fabs print die as close to the wafer edge as possible to maximize the number of devices per wafer. However, die near the wafer edge typically show the lowest yield. To address edge-yield issues, fabs need to control where the edge of each film lands—on the planar front surface of the wafer or past the planar surface into the sloped bevel—and match the perimeter of each film to those of films deposited before and after it during device processing.
VisEdge CV300R-EP provides a calibrated measurement of the profile of the wafer edge, including the slope of the bevel on which the film edge may land. In addition, VisEdge CV300R-EP is the first system to incorporate data from patterned edge die—including partial die—to trace the film edge and its concentricity with the wafer itself or with neighboring films in the process. Other solutions omit data from patterned areas, a method that may result in less accurate tracing of the film edge.
"Monitoring film concentricity is critical because overlapping film edges may lead to film delamination, increased edge defectivity and eventual yield loss," said Remo Kirsch, manager of Contamination Free Manufacturing at GLOBALFOUNDRIES, Inc. Fab1, located in Dresden, Germany.
"KLA-Tencor's VisEdge tool has the unique ability to trace the position of the edge of the copper film through both the patterned and unpatterned areas near the wafer edge, allowing us to determine the concentricity of the copper film with respect to the center of the wafer. We have implemented a daily monitoring strategy using the VisEdge system to qualify process chambers for the copper interconnect layers."
"Edge profile monitoring is another emerging use case for the VisEdge platform," said Oreste Donzella, vice president and general manager of the SWIFT division at KLA-Tencor.
"We have found that the bevel angle and other edge-profile parametric values can vary widely among wafer suppliers. Variations in the bevel angle, for example, can affect the structure of films at the outer perimeter, with implications for film integrity and ultimately wafer yield. The VisEdge CV300R-EP is able to identify wafers whose edge profiles do not meet process requirements."