CD & Overlay Metrology System

AST’s CD & Overlay Metrology System utilizing advanced measurement technology to ensure critical wafer features are within tolerance to achieve optimum performance and ensure wafer processes and specifications remain in control.  The capability to image through layers of the wafer to detect any misalignment caused by mask errors, process variations, and equipment inaccuracies during manufacturing are identified with a high-degree of precision and performance.  The ability of the AST-CDO system to be configured and implement tunable wavelength specific imaging of an overlay alignment pattern through multiple-layers of a wafer that may consist of differences of the material properties and characteristics that impact image quality and contrast for confirming layer-to-layer overlay alignment.  The AST-CDO system addresses and optimizes the measurement performance of each layer based on its wavelength transmission properties.