Example 5: Complex Trench Structure Refractive index and extinction coefficient of thin film materials

the trench structure depicted in adjacent diagram repeats in 160 nm intervals, is, has given pitch of 160 nm. trench composed of following materials:

accurate n , k values of these materials necessary in order analyze structure. blanket area on trench sample film of interest present measurement. in example, reflectance spectrum of poly-silicon measured on blanket area containing poly-silicon, n , k spectra determined in accordance methodology described in article utilizes forouhi-bloomer dispersion equations. fixed tables of n , k values used sio2 , si3n4 films.

combining n , k spectra of films rigorous coupled-wave analysis (rcwa) following critical parameters determined (with measured results well):