Abstract:
A substantially self-contained “on-board” material system investigation system functionally mounted on a three dimensional locational system to enable positioning at desired locations on, and distances from, the surface of a large sample, including the capability to easily and conveniently change the angle-of-incidence of a beam of electromagnetic radiation onto a sample surface.

Description:
This application Claims benefit of Provisional Applications 60/564,747 Filed Apr. 23, 2004, and 60/580,314 Filed Jun. 17, 2004. This application is further a Continuation-In-Part of Utility application Ser. Nos. 10/829,620 Filed Apr. 22, 2004 now U.S. Pat. No. 7,193,710; and of 10/925,333 Filed Aug. 24, 2004, and therevia of 10/050,802 Filed Jan. 15, 2002, (now U.S. Pat. No. 6,859,278). This application is further a Continuation-In-Part of Utility application Ser. No. 10/925,333 Filed Aug. 24, 2004, and of Ser. No. 10/829,620 Filed Apr. 22, 2004 now U.S. Pat. No. 7,193,710, and is a Divisional of Ser. No. 10/050,802 Filed Jan. 15, 2002 now U.S. Pat. No. 6,859,278; and via the above applications Claims Benefit of Provisional Application Ser. No. 60/261,243 Filed Jan. 16, 2001, 60/263,874 Filed Jan. 25, 2001, 60/287,784 Filed May 2, 2001. This application is further a CIP of Utility applications Ser. Nos. 10/699,540 Filed Nov. 1, 2003 now U.S. Pat. No. 7,158,231, and 10/857,774 Filed May 28, 2004, and therevia Claims benefit of Provisional Applications 60/424,589 Filed Nov. 7, 2002, 60/427,043 Filed Nov. 18, 2002, and 60/480,851 Filed Jun. 24, 2003. 

   TECHNICAL FIELD 
   The disclosed invention relates to reflectometer, spectrophotometer, ellipsometer, polarimeter and the like, and more particularly to a substantially self-contained “on-board” reflectometer, spectrophotometer, sellipsometer, polarimeter or the like system, which is functionally mounted on a three dimensional locational means to enable positioning it at desired locations on, and an offset distance from, the surface of a large sample and which enable easy sequential setting of different Angles-of-Incidence of a beam of electromagnetic radiation to a surface of said sample. 
   BACKGROUND 
   Spectrophotometer, reflectometer, polarimeter, ellipsometer and the like systems are known, (eg. Rotating Analyzer, Rotating Polarizer, Rotating Compensator, Modulator Element Ellipsometer), and the like systems (SYS) are known. Typical construction provides of such systems include a Sample Supporting Stage which is substantially fixed in location. Functionally oriented with respect thereto are a Substantially Fixed Position Source Means (S) for providing a beam of electromagnetic radiation at an oblique angle to said Sample Supporting Stage, and a Substantially Fixed Position Data Detector Means (D) for intercepting Electromagnetic Radiation with Reflects (or Transmits through), a Sample placed on said Sample Supporting Stage. Typical procedure is to place a Sample onto the Sample Supporting Stage, cause a beam of Electromagnetic Radiation to impinge thereonto, and record data produced by the Data Detector Means in response to electromagnetic radiation which enters thereinto, which data is analyzed to provide insight into Sample Optical and Physical properties. Said procedure can include adjustment of the Sample Supporting Stage in an “X”-“Y” Plane, and along a “Z” direction perpendicular to its surface, (ie. a vertical position adjustment where the Electromagnetic Radiation approaches the Sample at an oblique angle from a laterally located Source). This purpose of said adjustment is to, for instance, enable the directing of a beam of Electromagnetic Radiation Reflected from a Sample placed on said Sample Supporting Stage into the Data Detector without moving the Data Detector so it intercepts a beam exiting said Sample. It should be appreciated then that conventional Reflectometer, Spectrophotometer, Ellipsometer and Polarimeter Systems which include provision for such Sample positioning adjustment and orientation with respect to an impinging Electromagnetic beam, typically do so by allowing the Sample Supporting Stage position to be adjusted, rather than by effecting simultaneous change in location of the Source and Data Detector with respect to the Sample Supporting Stage, because it is far simpler to implement Sample Supporting Stage location change. 
   The present invention breaks with conventional practice by, while typically providing a substantially fixed position Stage for supporting a Sample, providing a Reflectometer, Spectrophotometer, Ellipsometer, Polarimeter or the like System which is mounted to a positioning system which allows adjustment its location in an “X”-“Y” Plane, and along a “Z” direction perpendicular to its surface of the Sample. The present invention then, allows investigation of a large Sample at many locations thereof. 
   Continuing, a typical goal in ellipsometry is to obtain, for each wavelength in, and angle of incidence of said beam of electromagnetic radiation caused to interact with a sample system, sample system characterizing PSI and DELTA values, (where PSI is related to a change in a ratio of magnitudes of orthogonal components r p /r s  in said beam of electromagnetic radiation, and wherein DELTA is related to a phase shift entered between said orthogonal components r p  and r s , caused by interaction with said sample system:
 
ρ= rp/rs =Tan(Φ)exp( i Δ)
 
   As indicated above, Ellipsometer Systems generally include a source of a beam of electromagnetic radiation, a Polarizer, which serves to impose a known, (typically linear), state of polarization on a beam of electromagnetic radiation, a Stage for supporting a sample system, and an Analyzer which serves to select a polarization state in a beam of electromagnetic radiation after it has interacted with a material system, and pass it to a Detector System for analysis therein. As well, one or more Compensator(s) can be present and serve to affect a phase retardance between orthogonal components of a polarized beam of electromagnetic radiation. A number of types of ellipsometer systems exist, such as those which include rotating elements and those which include modulation elements. Those including rotating elements include Rotating Polarizer (RP), Rotating Analyzer (RA) and Rotating Compensator (RC). A preferred embodiment is a Rotating Compensator Ellipsometer System because they do not demonstrate “Dead-Spots” where obtaining ellipsometric data is difficult. They can read PSI and DELTA of a Material System over a full Range of Degrees with the only limitation being that if PSI becomes essentially zero (0.0), one can&#39;t then determine DELTA as there is not sufficient PSI Polar Vector Length to form the angle between the PSI Vector and an “X” axis. In comparison, Rotating Analyzer and Rotating Polarizer Ellipsometers have “Dead Spots” at DELTA&#39;s near 0.0 or 180 Degrees and Modulation Element Ellipsometers also have a “Dead Spot” at PSI near 45 Degrees). The utility of Rotating Compensator Ellipsometer Systems should then be apparent. Another benefit provided by Rotating Compensator Ellipsometer Systems is that the Polarizer (P) and Analyzer (A) positions are fixed, and that provides benefit in that polarization state sensitivity to input and output optics during data acquisition is essentially non-existent. This enables relatively easy use of optic fibers, mirrors, lenses etc. for input/output. 
   While Data taken at one (AOI) and one or multiple wavelengths is often sufficient to allow ellipsometric characterization of a sample system, the results of Ellipsometric Investigation can be greatly enhanced by using multiple (AOI&#39;s) to obtain additional data sets. However, while it is relatively easy to provide Wavelength change without extensive difficult physical Ellipsometer System Orientation change, it is typically difficult to change the Angle-of-Incidence (AOI) that a Beam of Electromagnetic Radiation makes to a surface of a sample system. An (AOI) change requires that both the Source of the Electromagnetic Beam and the Detector must be re-positioned and aligned, and such is tedious and time consuming. 
   While present invention systems can be applied in any material system investigation system such as Polarimeter, Reflectometer, Spectrophotometer and the like Systems, an important application is in Ellipsometer Systems, whether monochromatic or spectroscopic. It should therefore be understood that Ellipsometry involves acquisition of sample system characterizing data at single or multiple Wavelengths, and at one or more Angle(s)-of-Incidence (AOI) of a Beam of Electromagnetic Radiation to a surface of the sample system. Ellipsometry is generally well described in a great many number of publications, one such publication being a review paper by Collins, titled “Automatic Rotating Element Ellipsometers: Calibration, Operation and Real-Time Applications”, Rev. Sci. Instrum, 61(8) (1990). 
   It is also noted that Ultraviolet (UV) or Infra-Red (IR) Wavelengths are absorbed by oxygen or water vapor, hence where they are applied, it is necessary to evacuate or purge at least the region around a sample. 
   Further, it is to be understood that causing a polarized beam of electromagnetic radiation to interact with a sample system generally causes change in the ratio of the intensities of orthogonal components thereof and/or the phase shift between said orthogonal components. The same is generally true for interaction between any system component and a polarized beam of electromagnetic radiation. In recognition of the need to isolate the effects of an investigated sample system from those caused by interaction between a beam of electromagnetic radiation and system components other than said sample system, (to enable accurate characterization of a sample system per se.), this Specification incorporates by reference the regression procedure of U.S. Pat. No. 5,872,630 in that it describes simultaneous evaluation of sample characterizing parameters such as PSI and DELTA, as well system characterizing parameters, and this Specification also incorporates by reference the Vacuum Chamber Window Correction methodology of U.S. Pat. No. 6,034,777 to account for phase shifts entered between orthogonal components of a beam of electromagnetic radiation, by present invention system multiangle prisms and/or lenses. 
   Another patent which is incorporated hereinto by reference is U.S. Pat. No. 5,969,818 to Johs et al. Said 818 Patent describes a Beam Folding Optics System which serves to direct an electromagnetic beam via multiple reflections, without significantly changing the phase angle between orthogonal components therein. Briefly, two pairs of mirrors are oriented to form two orthogonally related planes such that the phase shift entered to an electromagnetic beam by interaction with the first pair of mirrors is canceled by interaction with the second pair. 
   Another patents incorporated hereinto by reference is U.S. Pat. No. 5,757,494 to Green et al., in which is taught a method for extending the range of Rotating Analyzer/Polarizer ellipsometer systems to allow measurement of DELTA&#39;S near zero (0.0) and one-hundred-eighty (180) degrees. Said patent describes the presence of a window-like variable bi-refringent component which is added to a Rotating Analyzer/Polarizer ellipsometer system, and the application thereof during data acquisition, to enable the identified capability. 
   A patent to Thompson et al. U.S. Pat. No. 5,706,212 teaches a mathematical regression based double Fourier series ellipsometer calibration procedure for application, primarily, in calibrating ellipsometers system utilized in infrared wavelength range. Bi-refringent window-like compensators are described as present in the system thereof, and discussion of correlation of retardations entered by sequentially adjacent elements which do not rotate with respect to one another during data acquisition is described therein. 
   A patent to Woollam et al., U.S. Pat. No. 5,582,646 is disclosed as it describes obtaining ellipsometic data through windows in a vacuum chamber, utilizing other than a Brewster Angle of Incidence. 
   Patent to Woollam et al., U.S. Pat. No. 5,373,359, patent to Johs et al. U.S. Pat. No. 5,666,201 and patent to Green et al., U.S. Pat. No. 5,521,706, and patent to Johs et al., U.S. Pat. No. 5,504,582 are disclosed for general information as they pertain to Rotating Analyzer ellipsometer systems. 
   Patent to Bernoux et al., U.S. Pat. No. 5,329,357 is identified as it describes the use of optical fibers as input and output means in an ellipsometer system. 
   A Patent to Finarov, U.S. Pat. No. 5,764,365 is disclosed as it describes a system for moving an ellipsometer beam over a large two-dimensional area on the surface of a sample system, which system utilizes beam deflectors. 
   A Patent to Berger et al., U.S. Pat. No. 5,343,293 describes an Ellipsometer which comprises prisms to direct an electromagnetic beam onto a sample system. 
   A Patent to Canino, U.S. Pat. No. 4,672,196 describes a system which allows rotating a sample system to control the angle of incidence of a beam of electromagnetic radiation thereonto. Multiple detectors are present to receive the resulting reflected beams. 
   A Patent to Bjork et al., U.S. Pat. No. 4,647,207 describes an ellipsometer system in which reflecting elements are moved into the path of a beam of electromagnetic radiation. 
   U.S. Pat. No. 6,081,334 to Grimbergen et al. describes a system for detecting semiconductor end point etching including a means for scanning a beam across the surface of a substrate. 
   A Patent to Ray, U.S. Pat. No. 5,410,409 describes a system for scanning a laser beam across a sample surface. 
   U.S. Pat. No. 3,874,797 to Kasai describes means for directing a beam of electromagnetic radiation onto the surface of a sample using totally internally reflecting prisms. 
   U.S. Pat. No. 5,412,473 to Rosencwaig et al., describes a ellipsometer system which simultaneously provides an electromagnetic beam at a sample surface at numerous angles of incidence thereto. 
   A Patent to Chen et al., U.S. Pat. No. 5,581,350 is identified as it describes the application of regression in calibration of ellipsometer systems. 
   An article by Johs, titled “Regression Calibration Method For Rotating Element Ellipsometers”, which appeared in Thin Film Solids, Vol. 234 in 1993 is also identified as it predates the Chen et al. Patent and describes an essentially similar approach to ellipsometer calibration. 
   A paper by Nijs &amp; Silfhout, titled “Systematic and Random Errors in Rotating-Analyzer Ellipsometry”, J. Opt. Soc. Am. A., Vol. 5, No. 6, (June 1988), describes a first order mathematical correction factor approach to accounting for window effects in Rotating Analyzer ellipsometers. 
   A paper by Kleim et al, titled “Systematic Errors in Rotating-Compensator ellipsometry”, J. Opt. Soc. Am., Vol 11, No. 9, (September 1994) describes first order corrections for imperfections in windows and compensators in Rotating Compensator ellipsometers. 
   Other papers of interest in the area by Azzam &amp; Bashara include one titled “Unified Analysis of Ellipsometry Errors Due to Imperfect Components Cell-Window Birefringence, and Incorrect Azimuth Angles”, J. of the Opt. Soc. Am., Vol 61, No. 5, (May 1971); and one titled “Analysis of Systematic Errors in Rotating-Analyzer Ellipsometers”, J. of the Opt. Soc. Am., Vol. 64, No. 11, (November 1974). 
   Another paper by Straaher et al., titled “The Influence of Cell Window Imperfections on the Calibration and Measured Data of Two Types of Rotating Analyzer Ellipsometers”, Surface Sci., North Holland, 96, (1980), describes a graphical method for determining a plane of incidence in the presence of windows with small retardation. 
   Also, a paper which is co-authored by the inventor herein is titled “In Situ Multi-Wavelength Ellipsometric Control of Thickness and Composition of Bragg Reflector Structures”, by Herzinger, Johs, Reich, Carpenter &amp; Van Hove, Mat. Res. Soc. Symp. Proc., Vol. 406, (1996) is also disclosed. 
   Even in view of the prior art, need remains for:
         a material system investigation system which is functionally mounted to a two dimension location means for positioning said selected system at points in a two dimensional plane which is, in use, oriented substantially parallel to but offset from, the plane of a surface of a sample; and   a simple to use system for enabling easy sequential setting of different angle-of-incidence of a beam of electromagnetic radiation with respect to a surface of a sample system in ellipsometer, polarimeter, reflectometer, spectrophotometer and the like systems;   particularly where combined with an approach to account for any effects of the presence thereof, during evaluation of sample system PSI and DELTA values.       

   DISCLOSURE OF THE INVENTION 
   The presently disclosed invention breaks with conventional practice by teaching that the relative location between a Sample and a Source of Electromagnetic Radiation and a Data Detector in a Reflectometer or Ellipsometer and the like System should be accomplished by simultaneous motion of the Source of Electromagnetic Radiation and Data-Detector, (eg. in Lab coordinates), while the Sample remains substantially fixed, (eg. in said Lab Coordinates). While, it is not beyond the scope of the present invention to provide a Stage which can be moved, such is not a focus of thereof. The presently disclosed invention further breaks with convention by teaching that means to produce a Beam of Electromagnetic Radiation, Set and Detect Polarization States thereof, and to direct motion in Three Dimensions should be mounted self contained “On-Board” a mobile system. That is, in a presently realized embodiment, the only required external connections are means to provide electrical power and means to carry data from said Data Detector to a Data Analysis System, and in advanced embodiments under development, battery power is also provided On-Board, and Data is transmitted via a wireless On-Board Transmitter. 
   The direct incentive for developing the presently disclosed invention is found in the desire of producers of “Samples” which are very large, to be able to monitor many locations thereon For instance, such a “Sample” might be a sheet of glass which has dimensions of Feet/Meters on a side, whereas conventionally “Samples” placed on Ellipsometer Stages are measured in on the order of inches/centimeters on a side. For the purpose of enabling monitoring many locations on very large Samples it is beneficial to have a Self-Contained “On-Board” Ellipsometer which mounts to a Two Dimensional locational system, (eg. an “X”-“Y” Plotter-like System), near the surface of said Large Sample, said Self Contained Ellipsometer System having the “On-Board” capability of directing Two Dimensional location in a plane parallel to the substantially flat surface of a monitored large sample, and distance, (eg. “Z”), offset from said Large Sample at set locations within the Two-Dimensional plane. 
   An example of an ellipsometer system suitable for use in the present invention is a spectroscopic rotating compensator material system investigation system comprising a source of an incoherent polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and at least one detector system which contains a multiplicity of detector elements, said spectroscopic rotating compensator material system investigation system further comprising at least one Pseudo-Achromatic compensator(s) positioned at a location selected from the group consisting of:
         before said stage for supporting a material system;   after said stage for supporting a material system; and   both before and after said stage for supporting a material system.
 
Said ellipsometer system can further include means for flowing purge gas, such as Nitrogen, onto a region of a sample being investigated such that UV or IR wavelength electromagnetic radiation travels therethrough.
       

   The disclosed invention system can further comprise means for enabling easy provision of multiple Angles-of-Incidence of a beam of electromagnetic radiation with respect to a sample system surface in material system investigation systems such as:
         ellipsometer;   polarimeter;   reflectometer; and   spectrophotometer;   Mueller Matrix measuring system;
 
which operate at least one wavelength in at least one wavelength range, such as:
   VUV;   UV;   Visible;   Infrared;   Far Infrared;   Radio Wave.       

   In use, a disclosed invention electromagnetic beam intercepting angle-of-incidence changing system is situated near a sample system such that its functional effects can be easily entered into and removed from the path of an electromagnetic beam. When functionally in the path of the electromagnetic beam the disclosed invention system elements intercept electromagnetic beam radiation on both the impinging and reflected side of the sample system. When the disclosed invention electromagnetic beam intercepting angle-of-incidence changing system is caused to be functionally in the path of the electromagnetic beam it acts, via such as total internal reflection within multiangle prisms or functional equivalents, (eg. reflection from a sequence of mirrors), to direct said electromagnetic beam at the sample system at a different Angle-of-Incidence than is the case if the electromagnetic beam simply directly approaches and reflects from the sample system surface, however, and importantly as it is what provides the utility of the disclosed invention, the electromagnetic beam is directed to substantially the same spot, (eg. see the spot in  FIGS. 10 and 11  at which the beam impinges on the Sample (SS)), on a sample system being investigated. That is, the same spot on a sample system surface is addressed regardless of the presence of a disclosed invention Angle-of-Incidence changing system in the pathway of the electromagnetic beam. Further, as the electromagnetic beam Locus beyond the disclosed invention Angle-of Incidence changing system is not changed by a disclosed invention Angle-of-Incidence changing system, the presence thereof in the path of an electromagnetic beam does not require any realignment of a Source of the electromagnetic beam, or Detector thereof. In addition, where a disclosed invention system is entered into the locus of an electromagnetic beam by physical motion, multiple disclosed invention electromagnetic beam intercepting angle-of-incidence changing systems can be present adjacent to one another such that each can, as desired by a user, be sequentially physically moved into place, and thereby provide the possibility of sequentially easily effecting multiple different Angles-of-Incidence. When multiple different disclosed invention Angle-of Incidence changing system(s) are utilized, they are distinguished by the presence of differently shaped Multiangle prisms, or functional equivalents thereof, therewithin. Note, however, that as is described later herein, some embodiments of the disclosed invention system are held stationary in position, and which electromagnetic beam enters a detector is controlled by shutter doors and/or control of the transmission/reflection properties of an internal surface of a multiangle prism. 
   In practical application, the disclosed invention can then be described as:
         at least one electromagnetic beam intercepting angle-of-incidence changing system which comprises elements that are easily functionally entered into the locus of the electromagnetic beam on both sides of a sample system;
 
in functional combination with:
   a material system investigation system comprising a source of electromagnetic radiation, a means for supporting a sample system, and a detector, such that in use a beam of electromagnetic radiation is provided by said source of electromagnetic radiation and is caused to reflect from a sample system placed on said means for supporting a sample system and enter said detector.
 
As mentioned, said at least one electromagnetic beam intercepting angle-of-incidence changing system, when caused to be functionally present in the path of an electromagnetic beam, serves to direct said electromagnetic beam onto substantially the same spot on the sample system as is the case where said at least one electromagnetic beam intercepting angle-of-incidence changing system is not so functionally present, but at an angle-of-incidence which is different than that which exists when said at least one electromagnetic beam intercepting angle-of-incidence changing system is not functionally present. Importantly, said at least one electromagnetic beam intercepting angle-of-incidence changing system does not effect, or require change of the locus of the electromagnetic beams outside said at least one electromagnetic beam intercepting angle-of-incidence changing system, on either side of said means for supporting a sample system, hence present systems eliminate the requirement that a material system investigating system comprise multiple sources and/or detectors, or that the position of the source of electromagnetic radiation and/or detector thereof be changed during use to effect said electromagnetic beam angle-of-incidence change.
       

   At least one electromagnetic beam intercepting angle-of-incidence changing system can comprise, present on each side of said means for supporting a sample system, at least one selection from the groups consisting of:
         multiple angle prism(s); and   a system of mirrors;
 
said at least one electromagnetic beam intercepting angle-of-incidence changing system being slidably mounted to a guide element such that the functional presence thereof in the pathway of the locus of the electromagnetic beams on both sides of said means for supporting a sample system is effected by physical sliding motion of said at least one electromagnetic beam intercepting angle-of-incidence changing system along said guide element.
       

   Another embodiment of the disclosed invention system provides that at least one electromagnetic beam intercepting angle-of-incidence changing system comprises:
         a first multiangle prism on the incident side of said means for supporting a sample system and a second multiangle prism thereafter, said first and second multiangle prisms each having a first and a second side, each said multiangle prism presenting with first and second inner surfaces at said first and second sides respectively.
 
In this embodiment, the first and second sides of each multiangle prism have means for changing the properties of inner surface thereof from essentially transmissive to essentially reflective. Said means can be, for instance a voltage controlled liquid crystal array. In use, each multiangle prism is oriented such that an electromagnetic beam entering thereinto encounters said first or second inner surface thereof and either passes therethrough and progresses on to contact a sample system placed on said means for supporting a sample system; or reflects from said first or second inner surface thereof and then from said second or first inner surface thereof, respectively, and then progresses on to contact a sample system placed on said means for supporting a sample system. Said material system investigating system can further comprise at least one shutter door which can be opened to let the electromagnetic beam pass, or closed to block its passage, said at least one shutter door being positioned in the electromagnetic beam locus selected from the group consisting of:
   defined by transmission through said first or second side of said first multiangle prism; and   defined by reflection from said first or second side of said first multiangle prism;
 
said at least one shutter door being positioned between a first multiangle prism and the means for supporting a sample system and/or between said means for supporting a sample system and a second multiangle prism.
       

   Another embodiment of a disclosed invention material system investigating system provides that at least one electromagnetic beam intercepting angle-of-incidence changing system comprises:
         on first and second sides of said means for supporting a sample system, first and second, respectively, beam splitters.
 
Said first and second beam splitters each have the property that they pass approximately half, and reflect approximately half of a beam of electromagnetic radiation caused to be incident thereupon at an oblique angle to a surface thereof. Said at least one electromagnetic beam intercepting angle-of-incidence changing system further comprises a first reflective means positioned to intercept the approximately half of the electromagnetic beam which reflects from said first beam splitter on the incident side of said means for supporting a sample system and direct it toward said means for supporting a sample system. Also present is a second reflective means positioned after said means for supporting a sample system to intercept an electromagnetic beam which reflects from a sample system placed on said means for supporting a sample system and direct it toward the second beam splitter Said material system Investigating system further comprises at least one shutter door which can be opened to let the electromagnetic beam pass, or closed to block its passage, said at least one shutter door being positioned in the pathway of the electromagnetic beam between which progresses along a locus selected from the group consisting of:
       

   defined by passage through said first beam splitter; and 
   defined by reflection from said first beam splitter; 
   on either side of said means for supporting a sample system. Typically four shutter doors will be present, two on each side of the means for supporting a sample system, said shutter doors being positioned in the loci of the electromagnetic beams which are most easily identified as those transmitting through and reflecting from the beam splitter on the incident side of the means for supporting a sample system, although said beams are continuous past sample system from which they reflect. 
   The material system investigating system including the disclosed invention can also include means for adjusting the orientation of at least one angle-of-incidence changing element in an electromagnetic beam intercepting angle-of-incidence changing system, optionally in simultaneous combination with included lenses positioned to focus a beam of electromagnetic radiation onto a sample system. 
   Continuing, as taught in U.S. Pat. No. 5,969,818 to Johs et al., (which is incorporated herein by reference), the disclosed invention at least one electromagnetic beam intercepting angle-of-incidence changing system can comprise, on first and/or second sides of said means for supporting a sample system, at least one system of mirrors, said at least one system of mirrors being comprised of:
         a means for changing the propagation direction of an initial beam of electromagnetic radiation without significantly changing the phase angle between orthogonal components thereof, said means comprising two pairs of reflecting mirrors oriented so that said initial beam of electromagnetic radiation reflects from a first reflecting means in the first pair of reflecting means to a second reflecting means in said first pair of reflecting means, in a first plane; and such that the beam of electromagnetic radiation which reflects from the second reflecting means in said first pair of reflecting means reflects from the first reflecting means in said second pair of reflecting means to said second reflecting means in said second pair of reflecting means, in a second plane which is essentially orthogonal to said first plane; such that the direction of propagation of the beam of electromagnetic radiation reflected from the second reflecting means in said second pair of reflecting means is different from the propagation direction of the initial beam of electromagnetic radiation; the basis of operation being that changes entered between the orthogonal components by the first pair of reflective means is canceled by that entered by the second pair of reflective means.       

   It should be appreciated then that the disclosed invention is found primarily in the addition of disclosed invention Angle-of-Incidence changing system(s) to conventional material system investigation systems, and that the entering and/or removing procedure can be via physical motion of an angle-of-incidence changing system into and out of the locus of a beam of electromagnetic radiation, by operation of shutter doors statically placed in the locus of a beam of electromagnetic radiation, or by altering the properties of the inner surface of a multigangle prism statically placed to intercept a beam of electromagnetic radiation, to be transmissive or reflective. In any embodiment thereof, the utility of the disclosed invention is based upon the ease with which an angle-of-incidence of a beam of electromagnetic radiation to the surface of a sample system can be changed, (ie. typically attendant requirement for changing the position of a source and/or detector of electromagnetic radiation is not required). 
   The disclosed invention then comprises the Mounting of a material system investigation system such as Ellipsometer, Polarimeter, Reflectometer or Spectrophotometer System, (with or without a disclosed invention angle-of-incidence changing system present), on an X-Y-Z Position Control System so it can be moved around the surface of a large area Sample, (Z is for focus). While non-limiting, an example is that very large, (eg. multiple feet by multiple feet), slabs of glass are these days coated with Indium-Tin-Oxide. It is necessary to “Map” the sample system to determine if the (ITO) thickness is even over its area. A solution is to place an Ellipsometer on a system that allows it to be moved in X-Y-Z directions, then sequentially move it, and take data, and repeat. (Note that if an Ellipsometer or Polarimeter or Reflectometer System is mounted to move in an X-Z or Y-Z plane, instead of the X-Y plane, then the Y or X, respectively, direction is for focus). 
   Further, it is to be understood that the disclosed invention incorporates by reference the regression based calibration methodology of U.S. Pat. No. 5,872,630 into its operation to simultaneously evaluate sample system characterizing parameters such as PSI and DELTA, as well as Ellipsometer or the like and disclosed invention system characterizing parameters, and also incorporates by reference the Window Correction and correlation breaking methodology of U.S. Pat. No. 6,034,777 to account for phase shifts entered between orthogonal components of a beam of electromagnetic radiation, by disclosed invention system multiangle prisms, system of mirrors and optional lenses, or functional equivalents. 
   Again, disclosed invention angle-of-incidence changing systems can be used in Polarimeter, Reflectometer, Spectrophotometer and the like Systems, as well as in Ellipsometer Systems, whether monochromatic or over a spectroscopic wavelength range. 
   To aid with Disclosure as to how the disclosed invention can be practiced, relevant material from U.S. Pat. Nos. 5,872,630 and 6,034,777 is included directly herewithin. In particular, while not limiting, a relevant ellipsometer system to which the disclosed invention system can be described as comprising;
         a. a Source of a beam of electromagnetic radiation;   b. a Polarizer element;   c. optionally a compensator element;   d. (additional element(s));   e. a sample system;   f. (additional element(s));   g. optionally a compensator element;   h. an Analyzer element; and   i. a Detector System;
 
wherein, in the context of the disclosed invention, said additional component(s) in d. and f. each comprise at least one electromagnetic beam intercepting angle-of-incidence changing system element which can be easily entered into the locus of the electromagnetic beam on both sides of said sample system, which at least one electromagnetic beam intercepting angle-of-incidence changing system elements serves to direct said electromagnetic beam onto substantially the same spot on the sample system as is the case where the said at least one electromagnetic beam intercepting angle-of-incidence changing system elements are not present, but at an angle-of-incidence which is different than that when said at least one electromagnetic beam intercepting angle-of-incidence changing system is not present. Said at least one electromagnetic beam intercepting angle-of-incidence changing system elements does not effect, or requiring change of, the locus of the electromagnetic beams outside said at least one electromagnetic beam intercepting angle-of-incidence changing system elements, on either side of a sample system, hence does not require change of position of the source of electromagnetic radiation and/or detector to effect change said angle-of-incidence. The sample system investigation system electromagnetic beam intercepting angle-of-incidence changing system can comprise multiangle prisms and/or plurality of mirrors, and/or shutter doors and/or means for changing the characteristics of the internal surface of a multiangle prism etc.
       

   Continuing, under the teachings of the 630 Patent, each of said components b.-i. of the ellipsometer system must be accurately represented by a mathematical model, along with a vector which represents a beam of electromagnetic radiation provided from said source of a beam electromagnetic radiation identified in a above. 
   It is noted that various ellipsometer configuration provide that a Polarizer or Analyzer or Compensator(s) can be rotated during data acquisition, and are describe variously as Rotating Polarizer (RPE), Rotating Analyzer (RAE) and Rotating Compensator (RCE) Ellipsometer Systems. 
   The disclosed invention system then, is applied in a material system investigating system, (eg. ellipsometer; polarimeter; reflectometer; spectrophotometer or the like, operating in, for instance, a VUV, UV, Visible, Infrared, Far Infrared or Radio Wavelength range, and comprises a source of electromagnetic radiation, a means for supporting a sample system, and a detector, such that in use a beam of electromagnetic radiation is provided by said source of electromagnetic radiation and is caused to reflect from a sample system placed on said means for supporting a sample system and enter said detector, at an angle-of-incidence which can be set by said disclosed invention angle-of-incidence changing system. 
   The at least one electromagnetic beam intercepting angle-of-incidence changing system can comprise a selection from the group consisting of:
         multiple angle prism(s);   multiple angle prism(s) including means for changing the characteristics of internal surfaces thereof;   a system of mirrors;   shutter doors;
 
on each side of said sample system.
       

   As mentioned, the material system investigating system can be mounted to an X-Y-Z position control system and can be oriented to investigate a surface of a sample oriented in a horizontal or vertical or a plane thereinbetween. 
   A disclosed invention material system investigating system can include at least two multiple angle prisms at a location on at least one of said both sides of said sample system, and can include Lenses positioned to focus a beam of electromagnetic radiation onto a sample system. There can also be present means for adjusting the orientation of at least one multiangle prism, or functional equivalent, in a angle-of-incidence changing system, said means allowing adjusting the orientation of at least one lens alone or in fixed combination with an electromagnetic beam intercepting angle-of-incidence changing system multiangle prism or functional equivalent. 
   Another, purely mechanical, system for setting the angle of incidence of a beam of electromagnetic radiation comprises, as viewed in elevation, first and second arms pivotally interconnected to one another at an upper aspect thereof by a first pivot means, said first and second arms projecting downward and to the left and right of said first pivot means. Distal ends of said first and second arms are pivotally affixed to third and forth arms, said third and forth arms being pivotally interconnected to one another at a lower aspect thereof and said third and forth arms being projected upward and to the left and right of said pivotal interconnection at said lower aspect thereof, respectively. There are at least two pivotally affixed substantially downward projecting arms attached to each of said third and forth arms, distal ends of which are pivotally affixed to fifth and sixth arm which are not interconnected to one another, but project upward to the left and right, respectively. Affixed to one of said fifth and sixth arms is a source of a beat of electromagnetic radiation, and to the other of said sixth and fifth arms a detector of said beam of electromagnetic radiation is affixed. There is further a sample located such that a beam of electromagnetic radiation produced by said source of a beam of electromagnetic radiation reflects from an upper surface of said sample and enters said detector of said beam of electromagnetic radiation. In use when the first pivot means at which said first and second arms are interconnected is caused to be vertically raised or lowered, the angle of incidence at which the beam if electric radiation approaches said sample surface is changed, but the location at which it interacts with said sample surface remains substantially unchanged. 
   As already mentioned, the material system investigating system can be applied in a setting selected form the group consisting of:
         in-situ; and   ex-situ.       

   The disclosed invention will be better understood by reference to the Detailed Description Section of this Disclosure, with appropriate reference being has to the Drawings. 
   SUMMARY OF THE INVENTION 
   A primary purpose and/or objective of the disclosed invention is to teach a system comprising a system selected from the group consisting of:
         reflectometer;   rotating analyzer ellipsometer;   rotating polarizer ellipsometer;   rotating compensator ellipsometer;   modulation element ellipsometer;   Mueller Matrix measuring system;
 
functionally mounted to a two dimension location means for positioning said selected system at points in an two dimensional plane which is, in use, oriented substantially parallel to but offset from, the plane of a surface of a sample.
       

   Another primary purpose and/or objective of the disclosed invention is to teach said selected system comprises source means for providing a beam of electromagnetic radiation; and data detector means for detecting electromagnetic radiation; such that in use said selected system is located near the surface of said sample and a beam of electromagnetic radiation provided by said source means is caused to interact therewith and enter said data detector means; said selected system further comprising means for adjusting the location thereof at desired third dimension offset locations with respect to points in said plane of the surface of said sample; and said selected system further comprising means for controlling the location of the source means and data detector means in said two dimension plane. 
   A primary purpose and/or objective of the disclosed invention is to teach a system for enabling easy sequential setting of different Angles-of-Incidence of a beam of electromagnetic radiation to a surface of a sample system, in material system investigation systems such as ellipsometers, polarimeters, reflectometers, spectrophotometers and the like systems. 
   Another purpose and/or objective of the disclosed invention is to teach a regression based methodology for evaluating and compensating the effects of the presence electromagnetic beam intercepting angle-of-incidence changing systems, including where desired, parameterization of calibration parameters. 
   Other purposes and/or objectives will become obvious from a reading of the Specification and Claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1   a  demonstrates a perspective view of a Stage (STG) for supporting a Sample (S), said Stage (STG) being functionally combined with a Frame (F) which allows Frame (A) to move atop thereof. 
       FIG. 1   b  demonstrates addition of Black Box (E) atop Frame (A), said Black Box (F) being movable atop Frame (A). 
       FIGS. 2 and 3  demonstrate in Frontal and Side elevation that the contents of the Black Box (E) can comprise Ellipsometer, Polarimiter, Reflectometer, Spectrophotometer, Mueller Matrix Measuring and the like systems which comprise a Source (LS) and Detector (DET) of electromagnetic radiation. 
       FIG. 4  shows a generalized Ellipsometer System. 
       FIG. 5  shows application of a Multi-Element Detector to align a Sample. 
       FIG. 6  shows a system which can be applied to provide a signal allowing “X” and “Y” plane adjustment. 
       FIG. 7  shows a system which can be applied to provide a signal allowing “Z” distance adjustment. 
       FIG. 8  shows demonstrates a present invention ellipsometer system situated on “X”-“Y” control means above a large sample. 
       FIG. 9  demonstrates a present invention ellipsometer system situated on “X”-“Y” control means above a large sample, including a system for flowing purging gas onto a sample. 
       FIG. 10  shows a Front View of a Conventional Ellipsometer, Polarimeter or Reflectometer System with an Electromagnetic Beam shown approaching and reflecting from a sample system at an (AOI) of, for instance, 75 degrees. 
       FIG. 11  shows that the (AOI) is changed to, for instance, 60 degrees when a Present Invention System ( 1 ) is placed in the pathway of the Electromagnetic Beam. 
       FIG. 12   a  shows a Side View of Present Invention System(s) (S 1 ) (S 2 ) (S 3 ) mounted on a Guide (G) upon which they can be slid right and left. Present Invention System (S 1 ) is shown slid into position to intercept Electromagnetic Beam (E). 
       FIG. 12   b  shows a Side View of the system shown in  FIG. 3   a  with Present Invention System(s) (S 1 ) (S 2 ) (S 3 ) slid to the right therein such that none thereof intercepts Electromagnetic Beam (E). 
       FIG. 13  shows Multiangle Prisms (MAP) comprise a disclosed invention electromagnetic beam intercepting angle-of-incidence changing system on right and left sides thereof. 
       FIG. 14   a  shows how a Multiangle Prism (MAP) changes the pathway of an Electromagnetic Beam by Total Internal Reflection therewithin. 
       FIG. 14   b  shows how a plurality of Mirrors can change the pathway of an Electromagnetic Beam by Reflection therefrom. 
       FIG. 14   c  shows additional configurations of Multiple Angle Prisms (MAP 1 ) and (MAP 2 ) which have Shutters (SH 1 ) &amp; (SH 2 ), and (SH 3 ) &amp; (SH 4 ) respectively present thereupon. 
       FIG. 14   d  shows  FIG. 14   c  with door shutters (D 1 ), (D 2 ), (D 3 ) and (D 4 ) present therein. 
       FIG. 14   e  shows a system for providing multiple angles-of-incidence utilizing Beam Splitter, Reflective means and shutter doors. 
       FIG. 14   f  system is, however, identified as a particularly relevant way to use reflective means to alter the trajectory of a Beam of electromagnetic Radiation, without significantly changing the phase angle between orthogonal components thereof. 
       FIG. 15  shows a side elevational view of an adjustable mounting means for a Multiangle Prism (MAP), and optionally an Optical Lens (OL). 
       FIG. 16  shows a more detailed presentation of an ellipsometer system to which the Present Invention is applied. 
       FIG. 17   a  shows an approach to mounting Ellipsometer Polarization State Generator and Polarization State Analyzer Systems which allow easily changing the Angle-Of-Incidence of a Beam of Electromagnetic radiation caused to impinge on a Sample, as well as easily change the vertical height of thereof above the Sample. 
       FIG. 17   b  shows the system of  FIG. 17   a  indicated as present in a modified version of  FIG. 2   
   

   DETAILED DESCRIPTION 
   Turning now to the Drawings,  FIG. 1   a  demonstrates a perspective view of a Stage (STG) for supporting a large Sample (S), (eg. on the order of Feet/Meters in diameter), said Stage (STG) being functionally combined with a Frame (F) which allows a Frame (A) to move atop thereof in a (Y) direction. Note that Frame (A) has an open middle region through which a Beam (E) of electromagnetic radiation, (for example see  FIG. 2 ), can pass to reach the Sample (SS). 
     FIG. 1   b  demonstrates addition of Black Box (EB) atop Frame (A), said Black Box (EB) being movable in an (X) direction atop Frame (A). While Also shown is an optional Cable (CBL) which can serve to provide electrical power into, and carry Data Detector Signals to external Analysis means. The disclosed invention can, however, include “on-board” battery power sources, and/or wireless data transmission means for providing data to external analysis means. It is mentioned that while not shown, motion of the Black Box (EB) can be caused by any functional means. For instance, a motor/gear arrangement or where functional a motor/rubber wheel etc. can be applied between the Black Box (EB) and Frame (A), and between Frame (A) and Frame (F), as well as between Frame (C) and Frame (D) (see  FIG. 2 ). A functional motor can be a computer driven “Stepper Motor”. 
     FIGS. 2 and 3  demonstrate in Frontal and Side elevation that the contents of the Black Box (EB) can comprise Ellipsometer, Polarimiter, Reflectometer, Spectrophotometer, Mueller Matrix Measuring and the like systems which comprise a Source (LS) and Detector (DET) of electromagnetic radiation. Note the indication of possible movement of element (D), to which said Source (LS) and Detector (DET) are shown affixed, in the (Z) direction. 
   In use a Large Sample (S) is placed on the Stage (STG) with its upper surface oriented parallel to the plane formed by “X” and “Y” in  FIG. 1   a . Control Means (C) directs the positioning of the System (SYS) at a series of “X” “Y” and “Z” positions, whereat said positions Sample (S) investigation is desired to be conducted by causing said Source (LS) to provide a beam of Electromagnetic Radiation and direct it at an obliques angle onto the Upper Surface of said Sample, with reflected Electromagnetic radiation being entered into said Data Detector (DET). 
   (Note, the actual (X), (Y) and (Z) effecting motion means are not shown, but can comprise any functional motion causing means means, including Computer controlled Stepper Motors). 
     FIG. 4  shows a generalized Ellipsometer System. Shown are a Source of Electromagnetic Radiation (LS), a Polarizer (P), a Compensator (C), a Sample (MS) on a Sample Supporting Stage (STC), a Compensator (C′) a Focusing Lens (FE) a Dispersive Optics (D) and a Multi-Element Detector System. Removal of (P), (C), (C′) and (A) provides the general configuration of a Reflectometer. The Focusing Optics can in some systems be eliminated. Said system can be operated as Rotating Polarizer (P), Rotating Analyzer (A) or Rotating Compensator (C) and/or (C′) during data collection. For the purposes of this Disclosure, it is also to be understood that what is identified as a Compensator (C) (C′) could be a Modulation Element, (eg. electro-optic or magneto-optic etc.), with the result being a Modulation Element Ellipsometer. It is not the specific Reflectometer or Ellipsometer type which distinguishes the present invention. 
     FIGS. 5 ,  6  and  7  are included to demonstrate how signals indicating sample orientation with respect to “X” “Y” and “Z” orientations of the disclosed invention System (SYS) can be determined using Multi-Element Alignment Detectors (AD), said signals being provided to the disclosed invention Control Means (C).  FIG. 5  demonstrates a Multi-Element (eg. Quad), Alignment Detector (AD). Note that electromagnetic radiation is shown reflecting from a Sample (S) and undergoing some dispersal such that each Quad Detector Element (Q 1 ) (Q 2 ), (Q 3 ) and (Q 4 ) receives some input. It should be appreciated that orientation of the Sample (S), (eg. as achieved via indicated rotation around the shown axes), determines the amount of electromagnetic radiation which enters the various Quad Detectors. Further, it should be appreciated that were the sample moved significantly downward in  FIG. 5 , all electromagnetic radiation would miss the shown Quad Alignment Detector (AD).  FIG. 6  shows a configuration of an Alignment Detector which provides sensitivity to Sample Rotations, but not Vertical Height.  FIG. 7  shows a configuration of an Alignment Detector which provides sensitivity to Sample Vertical Height. (Note that the Central Hole (CH) in the  FIG. 5  Alignment Detector need not be present in the  FIG. 7  embodiment as electromagnetic radiation need not pass therethrough. 
     FIG. 8  shows demonstrates a present invention ellipsometer system (SYS) situated on “X”-“Y” control means above a large sample (S). Indicated in block form are (LS) and (P), and (A) and (DET). A Cable is shown which can be used to provide power to, and transmit data from the ellipsometer system (SYS). 
     FIG. 9  is similar to  FIG. 8 , but has means added for flowing purging gas onto a sample at the point it is being investigated, during a period in which UV and IR wavelength Electromagnetism interacts therewith. 
   It is noted that a Large Sample can be a single piece such as a large slab of glass, or can consist of a multiplicity small samples place on a base. Further, while the surface is typically flat, it can comprise some third dimension projections. 
   In use the system selected from the group consisting of:
         reflectometer;   rotating analyzer ellipsometer;   rotating polarizer ellipsometer;   rotating compensator ellipsometer;   modulation element ellipsometer;   Mueller Matrix measuring system;
 
can be thought of as “flying” over the sample.
       

   Continuing,  FIGS. 10-16  describe Angle-of-Incidence changing systems which can be added to the system of  FIG. 2 , and  FIGS. 17   a  and  17   b  demonstrate an alternative system which can replace the  FIG. 2  embodiment. 
     FIG. 10  shows a Front View of a Material System Investigating System, (eg. Ellipsometer, Polarimeter, Reflectometer or Spectrophotometer System), with an Electromagnetic Beam shown approaching and reflecting from a Sample System (SS) at an (AOI) of, for instance, 75 degrees with respect to normal.  FIG. 11  shows that the (AOI) is changed to, for instance, 60 degrees with respect to normal when a disclosed invention electromagnetic beam intercepting angle-of-incidence changing system ( 1 ) is placed in the pathway of the Electromagnetic Beam.  FIG. 12   a  shows a Side View of a disclosed invention electromagnetic beam intercepting angle-of-incidence changing system mounted on a Guide (G) upon which they can be slid right and left. The location of a Materials System Investigating System with respect to the disclosed invention electromagnetic beam (E) intercepting angle-of-incidence changing system is indicated by (E), which is the same (E) indicated in  FIGS. 10 and 11 . Referral to  FIGS. 12   a  and  12   b  shows that a sliding motion to the left will place a disclosed invention electromagnetic beam intercepting angle-of-incidence changing system (S 1 ) (S 2 ) (S 3 ) in the pathway of an Ellipsometer System Electromagnetic Beam (E), (see  FIG. 12   a ), and sliding disclosed invention electromagnetic beam intercepting angle-of-incidence changing system to the right moves them out of the Electromagnetic Beam, (see  FIG. 12   b ). (Note right and left in  FIGS. 12   a  and  12   b  correspond to a perpendicular to the plane of the surface of the paper in  FIGS. 10 and 2 . 
     FIG. 13  shows a Multiangle Prism (MAP) in a disclosed invention Electromagnetic Beam (E) intercepting Angle-of-Incidence changing system ( 1 ), on the left side thereof, (as indicated (BD) in  FIG. 12 ). Note that the orientation of the (MAP) increases the (AOI) in  FIG. 13 , whereas in  FIGS. 12 , (and  14   a ), the (MAP) is oriented to decrease the (AOI).  FIG. 14   a  shows how a Multiangle Prism (MAP) changes the pathway of an Electromagnetic Beam by Total Internal Reflection therewithin. The shapes and materials which characterize the prisms can be designed and selected to cause the (desired (AOI) change, as well as effect phase shifts entered by total internal reflections to be stable, or at least have small sensitivity to changes in (AOI). Polymer for Far IR, Silicon or Germanium for IR, and Quartz for UV, VIS-NIR or CaF for VUV, for instance, can be utilized. And note that a two or more Multiangle Prisms can be present on at least one side of the sample system, to provide an (AOI) not possible where only one is present.  FIG. 14   b  shows a plurality of mirrors (M) (M′) can also form disclosed invention electromagnetic beam intercepting angle-of-incidence changing system.  FIG. 13  also shows Optional Lenses (OL) can be positioned to focus a beam of electromagnetic radiation onto a spot on a sample system. Said Optional Lenses (OL) can be independently mounted, or affixed to the Multiangle Prisms (MAP). Note, it is possible to have two “Present Invention Systems” which provide the same AOI, one having Optional Lenses for focusing present, and the other not. 
     FIGS. 14   c  and  14   d  show additional configurations of Multiple Angle Prisms (MAP 1 ) and (MAP 2 ) which have Shutters (SH 1 ) &amp; (SH 2 ), and (SH 3 ) &amp; (SH 4 ) respectively present thereupon. Said Shutters (SH 1 ) &amp; (SH 2 ), and (SH 3 ) &amp; (SH 4 ) can be, for instance, voltage controlled liquid crystals or electromagnetic-optics means for effectively changing the refractive index of the top and bottom surfaces of a multi-angle prism, for the purpose of controlling the internal reflection/transmission properties.  FIG. 14   c  shows Input Electromagnetic Beam (EMB 1 ) entering Multi-Angle Prism (MAP 1 ) and interacting with the interface between said Multi-Angle Prism (MAP 1 ) and said Shutter (SH 1 ). If said interface is substantially transmissive then Beam (EA) proceeds to the Sample System, and reflects therefrom at point (P). Said Beam (EA) then proceeds through Multi-Angle Prism (MAP 2 ) and exits therefrom as Output Electromagnetic Beam (EMB 2 ). If, however, the interface between said Multi-Angle Prism (MAP 1 ) and said Shutter (SH 1 ) is substantially reflective, it should be appreciated that Input Electromagnetic Beam (EMB 1 ) will reflect thereat and become beam (EB). It is to be assumed that the interface between said Multi-Angle Prism (MAP 1 ) and said Shutter (SH 1 ) is also substantially reflective, so that beam (EB continues to reflect from Sample System, and reflects therefrom at point (P), and continue through Multi-Angle Prism (MAP 2 ), wherein it interacts with reflective interfaces between said Multi-Angle Prism (MAP 1 ) and said Shutters (SH 3 ) &amp; (SH 4 ) to emerge as Output Electromagnetic Beam (EMB 2 ). 
     FIG. 14   d  shows  FIG. 14   c  with additional Physical Door-Shutter means (D 1 ), (D 2 ), (D 3 ) and (D 4 ) in place to further enhance the Transmission/Reflection effect described with respect to  FIG. 14   c . For instance, when the interface between Multi-Angle Prism (MAP 1 ) and said Shutter (SH 1 ) is substantially transmissive, Physical Door-Shutter (D 2 ) will be open and Physical Door-Shutter (D 1 ) will be closed. The operation of Said Physical Door-Shutter means (D 1 ), (D 2 ), (D 3 ) and (D 4 ) must, of course, be coordinated with operation of Shutters (SH 1 ) &amp; (SH 2 ), and (SH 3 ) &amp; (SH 4 ), but when present serve to essentially completely overcome the effect of any imperfect operation of Shutters (SH 1 ) &amp; (SH 2 ), and (SH 3 ) &amp; (SH 4 ). 
     FIG. 14   e  shows an alternative system for effecting different angles of incidence. Note that a Beam Splitter (BS) receives a Beam of Electromagnetic Radiation (EM) and continuously reflects approximately half (EB) and transmits (EA) the remainder. The reflected portion (EB′) reflects from a Second Reflection means (R 2 ). Both the reflected (EB′) and Transmitted (EA) Electromagnetic Beams arrive at the same point on Sample System (SS), but at different angles-of-incidence. Note, importantly, that Door Shutters (D 5 ) and (D 6 ) are present, and are operated to block one or the other of (EA) and (EB′) when desired. After the Sample System (SS), whether it is electromagnetic beam (EA) or (EB′) which is allowed to proceed, note that it makes its way to the Detector (DET) by a pathway which is a mirror image to that which brought it to the Sample System (SS) from the Electromagnetic Beam Source. Note that typically four shutter doors (D 5 ) (D 6 ) (D 5 ′) (D 6 ′) are be present, two on each side of the sample system (SS), said shutter doors being positioned in the loci of the electromagnetic beams which transmit through (EA) and reflect from (EB′) the beam splitter (BS) on the incident side of the means for supporting a sample system (SS). 
   It is important to mention U.S. Pat. No. 5,969,818 to Johs et al. which is incorporated hereinto by reference. Said 818 Patent describes a Beam Folding Optics System which serves to direct an electromagnetic beam via multiple reflections, without significantly changing the phase angle between orthogonal components therein. Briefly, two pairs of mirrors are oriented to form two orthogonally related planes such that the phase shift entered to an electromagnetic beam by interaction with the first pair of mirrors is canceled by interaction with the second pair. The Reflector (R 2 ) in  FIG. 14   e , (and a similar Reflector in an output side) can comprise Patent 818 Beam Folding Optics.  FIG. 5  from said 818 Patent is reproduced herein as  FIG. 14   f . Note that Beam (EB) in  FIG. 14   e  is shown as is Beam ((EB′), and that Mirrors  1  and  2  form a First Pair, and Mirrors  3  and  4  a Second Pair. Note how the Planes of incidence  1  and  2  are orthogonally related to one another. It is not a focus of Patentability herein to specify any particular  FIG. 14   e  Second Reflective Means (R 2 ) system. The  FIG. 14   f  system is, however, identified as a particularly relevant way to use reflective means to alter the trajectory of a Beam of Electromagnetic Radiation, without significantly changing the phase angle between orthogonal components thereof. Such an effect is similar to that provided by Total Internally Reflective Multi-Angle Prisms, as shown in  FIGS. 13 ,  14   a ,  14   c  and  14   d  herein. 
   The disclosed invention system also typically includes means for adjusting, for instance, tilt, translation and rotation orientations of the multi-angle prisms and/or the Optional Lenses (OL) within the containing structure. Such presence facilitates easy system set-up optimization.  FIG. 15  demonstrates mounting Bases (B 1 ), (B 2 ) and (B 3 ) mounted with respect to one another so that mounting Base ( 2 ) can move right and left on mounting Base ( 1 ), and so that mounting Base ( 3 ) can rotate on mounting Base ( 2 ). A Multiangle Prism (MAP) is shown mounted to mounting Base ( 3 ). Mounting Base ( 1 ) can of course be mounted in a Present Invention Electromagnetic Beam (E) intercepting Angle-of-Incidence (AOI) changing system ( 1 ), as shown in  FIG. 12 , in the position of (BD) or (BD′) in a manner to allow it Rotational or any Linear Degrees of Motion Freedom. In particular motion into and out of the plance of the paper is also possible at the (B 1 ), (B 2 ) and/or (B 3 ) level, as required. Note that an Optical Lens (OL) is also shown rotatably and translatably mounted via mounting Base (B 4 ) to mounting Base ( 1 ). This is an optional feature, and it is noted that the Optical Lens (OL) can be absent, or separately mounted.  FIG. 15  is to be considered only demonstrative, and functional mountings can include any required translation, tilt and rotation adjustment capability shown, and not directly shown or visible in the view presented. 
   It is also to be appreciated that while an Electromagnetic Beam (E) which interacts with a Sample System (SS) will often be polarized, where the disclosed invention system ( 1 ) is used with a Reflectometer System, this need not be the case. Reflectometers which produce unpolarized electromagnetic radiation and cause impingement at oblique (AOI&#39;s), (instead or in addition thereto ellipsometer produced beams), can have the disclosed invention applied thereto as well. 
     FIG. 16  provides a general elemental configuration of an ellipsometer system ( 10 ) which can be applied to investigate a sample system (SS). Shown are, sequentially:
         a. a Source of a beam electromagnetic radiation (LS);   b. a Polarizer element (P);   c. optionally a compensator element (C 1 );   d. (additional element(s)) (AC 1 );   e. a sample system (SS);   f. (additional element(s)) (AC 2 );   g. optionally a compensator element (C 2 );   h. an Analyzer element (A); and   i. a Detector System (DET).       
   It is noted that the elements identified as (LS), (P) and (C 1 ) can be considered to form, as a group, a Polarization State Generator (PSG), and the components (C 2 ), (A) and (DET) can be considered, as a group, to form a Polarization State Detector (PSD). It is to be understood that the d. and f. “additional elements”, (AC 1 ) and (AC 2 ), can be considered as being, for the purposes of the disclosed invention Disclosure, input and output electromagnetic beam intercepting angle-of-incidence changing system elements. (Note the presence of indication of an Electromagnetic Beam (E) in  FIG. 16 , which for orientation it is noted corresponds to the location shown in  FIGS. 12 ,  12   a  and  12   b ). 
   Where, as is generally the case, input (AC 1 ) and output (AC 2 ) additional elements, (eg. multiangle prisms or functional equivalents as represented by (BD) and (BD′) in  FIG. 12 ), have bi-refringent characteristics, it must be appreciated that said characteristics must be accounted for in a mathematical model of the ellipsometer and sample system. 
   It is to be appreciated that single systems shown  FIGS. 14   c ,  14   d ,  14   e  can be fixed in place and various shutters and door shutters operated to effect beam directing. However, multiple embodiments shown in said  FIGS. 14   c ,  14   d  and  14   e  can be mounted to a slidable means to enable effecting any of a plurality of angles-of-incidence. Once in place however, two angles-of-incidence can be effected by a  FIG. 14   c ,  14   d  or  14   e  system without physically moving it into an out of a beam of electromagnetic radiation. 
   It is beneficial at this point to refer to the paper by Johs, titled “Regression Calibration Method for Rotating Element Ellipsometers”, which was referenced in the Background Section of this Disclosure. Said paper describes a mathematical regression based approach to calibrating rotating element ellipsometer systems. Said calibration procedure provides that data, (eg. ellipsometric ALPHA and ellipsometric BETA values), be obtained as a function of an ellipsometer system Polarizer Azimuth, as said Polarizer Azimuth is stepped through a range of angles, (eg. sixty (60) degrees to one-hundred-sixty (160) degrees). A mathematical model of the ellipsometer system and a sample system under investigation is provided, and a mathematical square error reducing technique is applied to evaluate parameters in said mathematical model. Successful calibration leads to experimental data and calculated data curves being essentially coincident. 
   Further insight to the benefit of applying 630 Patent-type regression calibration, and 777 Patent window-like effect corrections to ellipsometer and the like systems which include the disclosed invention multiple-AOI providing system, having then been illuminated herein, can be found in said 630 and 777 Patents which are incorporated by reference in this Specification. Said 777 Patent demonstrates that a methodology for correcting for affects of acquiring ellipsometric data through standard vacuum chamber windows, which can be applied to correcting affects of disclosed invention (AOI) changing systems, has been developed and tested. The key insight enabling said accomplishment is that bi-refringence can be split into “out-of-plane” and “in-plane” components, where the “plane” referred to is the plane of incidence of an electromagnetic beam of radiation with respect to a sample system. Splitting the electromagnetic beam into said orthogonal components allows derivation of second order corrections which were tractable while allowing an ellipsometer system calibration procedure to determine values of parameters. Again, said ellipsometer system calibration procedure allows parameter values in “out-of-plane” component retardation representing equations to be directly evaluated, with the “in-plane” component being an additive factor to a sample system DELTA. A separate step, utilizing a sample system for which retardation can be modeled by a parameterized equation, allows evaluation of the parameters in parametric equations for the “in-plane” components of windows separately. Work reported in the literature by other researchers provided equations which corrected only first order effects, and said equations have proven insufficient to correct for large, (eg. six (6) degrees), of retardation which is typical in standard vacuum chamber windows and which can occur in disclosed invention (AOI) changing systems. It is noted that each total internal reflection in a multiangle prism can impart up to about 45 degrees retardance, depending on the internal reflection angle. Four such bounces can then impart on the order of 160 degrees total phase retardance between the electromagnetic beam orthogonal components. 
   Continuing to use vacuum chamber windows as example, it is noted that said prior work orthogonal components were derived with respect to window fast axes, which is offset from the sample system plane of incidence). Where the window retardance becomes small, (eg. at longer wavelengths), parameter evaluation in equations for said orthogonal components becomes difficult, as it becomes difficult to determine fast axis orientation. This means that where fast axis orientation can not be identified, algorithm instability becomes a problem. Furthermore, the fast axis orientation of window retardance would also correlate with a sample system DELTA parameter unless a global regression fit using a parameterizable sample system is performed at calibration time. Said methodology comprising two steps as disclosed herein, fully and unambiguously determines correction terms in-situ. 
   After parameters in parameterized equations for retardance are evaluated by the method of the disclosed invention, ellipsometric data can be taken through disclosed invention (AOI) changing systems and said data can be quickly and accurately analyzed by applying the correction factors in a mathematical model for a sample system, (in the case where a Rotating Analyzer ellipsometer system was used to acquire data), or the (AOI) changing system effects can be simply quantitatively subtracted away to yield “true” ellipsometric PSI and DELTA values, (in the case where a Rotating Compensator ellipsometer system was used to acquire data). Finally, it is noted that the Patent to Johs et al. U.S. Pat. No. 6,034,777, provides demonstrative data obtained by practice of the described correction methodology as applied to other systems. Said data is incorporated by reference herein and should be considered as demonstrative of results obtained when it is applied to systems including disclosed invention (AOI) changing systems. 
   It is noted that shutters (SH 1 ) (SH 2 ) (SH 3 ) (SH 4 ) and shutter doors (D 1 ) (D 2 ) (D 3 ) (D 4 ) (D 5 ) (D 6 ) (D 5 ′) (D 6 ′) can be of any functional type, such as mechanical or voltage driven liquid crystal devices. 
   Finally,  FIGS. 17   a  and  17   b  show a mechanical system for mounting a Reflectometer or Spectrophotometer Source and Detector, or Ellipsometer or Polarimeter Polarization State Generator, (eg. Source, Polarizer and optionally compensator), and Polarization State Analyzer, (eg. optional Competitor, Analyzer and Detector), Systems. Said approach to mounting allows easily changing the Angle-of-Incidence of a Beam of Electromagnetic radiation caused to impinge on a Sample. Said system for setting the angle of incidence of a beam (E) of electromagnetic radiation comprises, as viewed in elevation, First (FA) and Second (SA) arms pivotally interconnected to one another at an upper aspect thereof by a First Pivot Means (FPM), said first (FA) and second (SA) arms projecting downward and to the left and right of said First Pivot Means (FPM); distal ends of said First (FA) and Second (SA) arms being pivotally affixed to Third (TA) and Forth (FA) arms, said Third (TA) and Forth (FA) arms being pivotally interconnected to one another by Second Pivot Means (SPM) at a lower aspect thereof, said Third (TA) and Forth (FA) arms being projected upward and to the left and right of said Second Pivot Means (SPM) at said lower aspect thereof; there being at least two pivotally affixed substantially Downward Projecting Arms (DPA) to each of said Third (TA) and Forth (FA) arms, distal ends of which are pivotally affixed to Fifth (FAA) and sixth (SA) arms which are not interconnected to one another, but project upward to the left and right, respectively. There are affixed to one of said Fifth (FAA) and Sixth (SA) arms a Source (LS) of a beam of electromagnetic radiation, and to the other of said Sixth (SA) and Fifth (FAA) arms a Detector (DET) of said Beam (E) of electromagnetic radiation. There is further a Sample (SS) located such that a Beam (E) of electromagnetic radiation produced by said Source (LS) of a beam of electromagnetic radiation reflects from an upper surface of said Sample (SS) and enters said detector of said beam of electromagnetic radiation, such that in use when the First Pivot Means (FPM) at which said First (FA) and Second (SA) arms are interconnected is caused to be vertically raised or lowered, the angle of incidence at which the Beam (E) of electric radiation approaches said sample surface is changed, but the location at which it interacts with said Sample (SS) surface remains substantially unchanged. 
   It is noted that designators (E), (EM), (EMB 1 ), (EMB 2 ) in the various Figures all identify a Beam of Electromagentic Radiation from a Source (LS) thereof. 
   It is also noted that  FIG. 17   b  shows the system of  FIG. 17   a  in a Black Box (EB) much like  FIG. 2  showed an Ellipsometer of an alternative design. Likewise,  FIGS. 10 ,  11 ,  13  and  14   a - 14   e  show Sources (LS) and Detectors (DET) which can be considered to be those in  FIG. 2  such that they intercept the Beam (E) of electromagnetic radiation on both sides of the Sample (SS). 
   It is noted that Reflectometer, Spectrophotometer Ellipsometer, Polarimeter, Mueller Matrix Measuring System and the like systems can be generically termed “material system investigating systems”. 
   Having hereby disclosed the subject matter of the present invention, it should be obvious that many modifications, substitutions, and variations of the present invention are possible in view of the teachings. It is therefore to be understood that the invention may be practiced other than as specifically described, and should be limited in its breadth and scope only by the Claims.