Semiconductor metrology for wafer topography
An essential aspect of imaging defects in wafers involves characterization of the diffraction of the X-rays due to the crystal lattice. A wafer to be inspected is oriented in such a way that the Bragg-condition for diffraction is only met (or nearly met) for just one set of lattice planes. All defects with strain fields will locally deform the lattice and thus change the Bragg condition at that point. The intensity of the diffracted beam will then react to this and vary around defects - effecting a pattern that may be imaged. This technology is provided in an automated X-ray topographic imaging system, the Rigaku XRT series, which can accommodate Si wafers up to 300 mm diameter.
A pioneer and world leader in designing and manufacturing X-ray based measurement tools to solve semiconductor manufacturing challenges, Rigaku has provided over 30 years of global semi metrology leadership.