Light Scattering From A Single Particle On A Silicon Surface

Defects or their effects are the main reason of invalidating integrated circuit (IC) chips. Strict detection and control are needed urgently to wafer surface quality in IC process. However, the defects inspection of laser is a set of nondestructive testing.In order to improve inspectability for microparticles defect of laser inspection system, a mathematical model of a particle on a semiconductor surface is founded, through which scattering theories are studied. Then the intuitional images of scattered field are gained. So it will solve the key technologies in the system of surface fault diagnosis and help the engineers to design delicacy and effective diagnostic tools .When the calculation of light scattering by particle is calculated, by Maxwell's equations and the mathematical formulation of the boundary value, based on the addition theorem of spherical vector wave functions, incident and scattered fields are expanded into spherical vector wave functions, and it leads to the T-matrix, a transferring matrix between expansion coefficients of the fields. A new method -discrete source is introduced instead of the extended boundary condition method(EBCM) to calculation of transferring matrix. Super-ellipsoid function is utilized to simulate various shapes of particles, and its geometric information on the particle is obtained by triangularizing its surface. With the geometric information in combination with null-field, T-matrix of arbitrary-shaped particle can be found. T-matrix method is also introduced into light scattering from particles on or near a surface, scattering by infinite surfaces is computed by T-operator formalism .On basis of the theory, light scattering by a particle on or near an infinite surface is determined. To the light scattering by a particle on or near a surface there are three kinds of fields: directly incident field, reflected field and interacting field. The reflection matrix is used to calculate the interacting field, and it is revolved with interacting expansion of plane wave and spherical wave. At the end, the simulating results are given.