KLA Corporation
Apparatus and method for measuring topography and gradient of the surfaces, shape, and thickness of patterned and unpatterned wafers

Abstract:

An interferometer system may include a stage assembly configured to receive and secure a sample, an illumination source configured to generate an illumination beam, a half-wave plate, one or more shearing prisms to shear the illumination beam into two beamlets along a shearing direction, a reference flat disposed proximate to the sample, a detector assembly, and a controller. The controller may cause the illumination source to generate an illumination beam and sweep the illumination beam across a plurality of wavelengths, and determine both a surface height measurement and a surface slope measurement of the sample based on the illumination received by the detector assembly.