Apparatus and method for measuring a property of a layer in a multilayered structure

An apparatus for evaluating an annealed structure, said annealed structure comprising a partially transmissive electrically conductive layer, said layer comprising at least one suicide among a plurality of silicides, said apparatus having a first line to be coupled to an annealing apparatus and a second line to be coupled to a metal formation apparatus, said apparatus comprising:

• a first source of a first beam of photons having a first power modulated at a frequency sufficiently low to ensure transfer of a majority of heat from a region of said layer illuminated by said first beam by diffusion;
• a second source of a second beam of photons having a second power sufficiently low to ensure that an instantaneous temperature in said region is approximately equal to another temperature obtained in said region by heating with an unmodulated beam having power of an instantaneous value of said first power;
• and
• a photosensitive element located in a path of a portion of said second beam after reflection from said region, said portion being modulated at said frequency of modulation of said first beam;
• and
• a computer coupled to said photosensitive element and programmed to determine if power of said portion of said second beam reflected by said region is at least greater than a predetermined power and if so the computer driving a signal active on the first line to the annealing apparatus or on the second line to the metal formation apparatus or both.

A method for evaluating a wafer, the method comprising:

• focusing a beam on a partially transmissive electrically conductive layer in said wafer, the partially transmissive electrically conductive layer comprising at least one silicide among a plurality of silicides, whose roughness is a function of crystal phase, and wherein said one silicide is formed by annealing;
• measuring reflectance of said beam from said layer;
• and
• correlating said reflectance from said layer to a previously determined value said previously determined value having been obtained from a previous reflectance measurement on a reference wafer.