Very high magnification optical characterization of global and local distortion of Si wafers after laser spike annealing

The understanding of macro- and micro-scale wafer shape changes during device fabrication process steps is becoming very critical in developing and optimizing advanced technology node devices in which new materials such as Ni, NiPt and/or Ge are introduced. We have developed a non-contact, in-line process and/or material property monitoring method which uses various forms (reflection, diffraction, interference and scattering) of interactions between semiconductor wafers and a laser beam. Laser spike anneal (LSA) induced changes of surface profiles in TiN/NiPt/Si_1-xGe_x/Si (100) and Si_1-xGe_x/Si (100) wafers are characterized using the newly developed very high magnification optical surface profilometry (OSP-300) system. Significant global and local changes of wafer surface profiles were observed after LSA. Multi-wavelength micro-Raman studies revealed significant changes in Ge content and lattice level stress in Si_1-xGe_x/Si (100) wafers annealed under various LSA temperatures and dwell times.