Method of determining refractive index, extinction coefficient, and surface properties of prism shaped material

A method of simultaneously determining the refractive index of a prism shaped material for a multiplicity of wavelengths, comprising the steps of:

• a) providing a system comprising:
• a1) a stage for supporting said prism shaped material,
• a2) a source of a spectroscopic beam of electromagnetic radiation:
• mounted directly to a rotatable support arm on a source side of said prism shaped material, or
• mounted other than to said rotatable support arm and provides a spectroscopic beam via a beam director attached to a support arm on a source side of said prism shaped material;
• and a wavelength disperser and multi-element detector of different wavelengths in a beam of electromagnetic radiation mounted:
• directly to a separate rotatable support arm on a detector side of said prism shaped material, or
• other than to said rotatable support arm and directs a spectroscopic beam via a beam director mounted to a support arm on a detector side of said prism shaped material;
• said source side and detector side rotatable support arms each being rotatable about a common axis so as to enable directing a beam of electromagnetic radiation, provided by said source of a beam of electromagnetic radiation, at various angles of incidence to said source side of said prism shaped material such that it enters said prism shaped material, is refracted thereby, passes through said prism shaped material and exits from said detector side of said prism shaped material at a refracted exit angle to said detector side of said prism shaped material, and then proceeds toward said wavelength disperser where it is dispersed into separate wavelengths which enter said detector of spectroscopic beam of electromagnetic radiation;
• a3) means for adjusting each of the source side and detector sides rotatable support arms through equal angles by rotation about said common axis;
• and
• a4) a computer;
• b) mounting a prism shaped material to said stage, said prism shaped material having converging source and detector sides that form an apex angle “A” where they intersect;
• c) while causing said source of a beam of electromagnetic radiation to produce a spectroscopic beam of electromagnetic radiation, rotating said rotatable support arm on said source side of said prism shaped material counterclockwise or clockwise through a range of angles to direct a beam of electromagnetic radiation toward the source side of said prism shaped material at an angle of incidence to said source side thereof, and rotating said separate rotatable support arm on said detector side of said prism shaped material clockwise or counterclockwise, respectively, through the same range of angles as was the rotatable support arm to which the source is attached, and simultaneously monitoring the intensity of a multiplicity of dispersed wavelengths in said beam entering different detecting elements of said detector as a result;
• d) monitoring the intensity of each of said multiplicity of dispersed wavelengths in the beam entering the multiple elements of said detector as a result by so doing determining the optimum angle of incidence of each wavelength in said electromagnetic beam with respect to said source side of said prism shaped material at which the detector indicates a maximum intensity;
• and
• e) for the optimum maximum intensity angle of incidence determined in step d), in said computer, applying the following formula:
• n
• ⁢
• ⁢
• 2
• =
• (
• sin
• ⁢
• ⁢
• (
• (
• A
• +
• (
• 180
• -
• 2
• ⁢
• (
• θ
• )
• ⁢
• ⁢
• optimum
• ⁢
• ⁢
• angle
• )
• )
• /
• 2
• )
• )
• sin
• ⁢
• ⁢
• (
• A
• /
• 2
• )
• ⁢
• n
• ⁢
• ⁢
• 1
• to determine n2,
• where n1 and n2 are the refractive indicies of the ambient environment surrounding said prism shaped material, and of said prism shaped material, respectively, where n2 is wavelength dependent;
• and
• f) said method further comprising adapting the source provided in step a2), or providing a different source of electromagnetic radiation to serve as an ellipsometer system source of a beam of electromagnetic radiation, then causing a beam provided thereby to pass through a polarization state generator, follow a substantially similar path as did the source of a beam of electromagnetic radiation provided in step a2) through said prism material oriented as in step e), pass through a polarization state analyzer and enter the same detector as also provided in step a2), or a different detector of electromagnetic radiation, which same or different detector serves as said ellipsometer system detector, followed by acquiring ellipsometric data from said detector and applying it to characterize surface properties of said prism.