Wafer with overlay test pattern

Abstract

A method of X-ray analysis includes irradiating a spot on a sample with X-rays along an X-ray beam axis. X-rays emitted from the sample, responsive to irradiating the spot, are simultaneously detected at a plurality of different azimuthal angles relative to the beam axis. X-ray intensities detected at the different angles in a common energy range are compared in order to determine a property of the sample.

1 . A semiconductor wafer having at least an upper and a lower metal layer deposited thereon, the layers comprising respective upper and lower features defining a test pattern on the wafer, such that the upper feature substantially shields the lower feature from radiation when the upper and lower metal layers are properly registered with one another, but does not shield at least a portion of the lower feature when the layers are not properly registered.  
     
     
         2 . A wafer according to  claim 1 , wherein the lower feature comprises a first metallic material, and wherein the upper feature comprises a second metallic material, the first and second materials having substantially different X-ray fluorescence spectra.