Synchrotron X-ray topographic study of strain in silicon wafers with integrated circuits

Section topographs made with synchrotron radiation show the strain field below the surface of silicon wafers which have gone through a process for integrated circuits. The contrast observed is a series of curved lines starting at one edge of an oxide layer and ending at its other edge. The strain is also calculated using the finite-element method. Electrical measurements such as the threshold voltage of a transistor are made in order to find the influence of the strain on the device performance and yield.