Full-Wafer Defect Identification using X-ray Topography

The timely identification of defects can lead to increased yields and significant cost savings in wafer production. X‐ray topography (XRT) is recognized as being a powerful tool for directly imaging defects in single crystals, such as semiconductor substrates and epitaxial thin‐films. In XRT, defects are imaged by measuring changes in the diffracted X‐ray intensity across a wafer due to strain and/or tilt that the defects introduce into the crystal lattice. We have developed a novel, high‐speed digital XRT method for non‐destructive defect characterization of up to 300mm diameter wafers. This method, called BedeScan™, offers substantial advantages to conventional topography, especially for rapid, convenient defect identification in a wafer manufacturing/processing environment. X‐rays from a microfocus source are diffracted from a wafer, which is translated with fast, high‐precision motions in front of a fixed CCD camera and a sequence of images is recorded. A virtual scan of the camera in the computer is ...