Abstract
Ellipsometer, polarimeter, reflectometer and spectrophotometer systems including one or more wavelength modifiers which convert wavelengths provided by a source of electromagnetic radiation to different wavelengths for use in investigating a sample, and/or which a detector thereof can detect.
Claims
1.-22. (canceled)
23. A sample investigation system selected from the group consisting of: an ellipsometer; a polarimeter; a reflectometer; and a spectrophotometer; for use in investigation samples with electromagnetic radiation; said system comprising: a source (LS) of electromagnetism; a stage (STG) for supporting a sample; and a detector (PA) which comprises detector elements (DE's); said system source (LS) providing long wavelength electromagnetic radiation in the IR and THZ ranges, and said detector comprising solid state elements (DE's) which cannot detect said IR and THZ wavelengths; said system being characterized by the presence of, prior to said detector (PA), at least one wavelength modifier (WM) for accepting electromagnetic radiation of wavelengths outside the range of said detector (PA) detector elements (DE's) can detect, and providing output electromagnetic radiation based thereupon of wavelengths which said detector elements (DE's) can detect.
24. A sample investigation system as in claim 23, which further comprises polarization state generator (PSG) and polarization state analyzer (PSA) components before and after said stage (STG) respectively, and the system is an ellipsometer.
25. A sample investigation system as in claim 23, in which the at least one wavelength modifier (WM) accepts electromagnetic radiation comprising wavelengths in the IR and THZ ranges and outputs electromagnetic radiation with wavelengths in the visible wavelength range.
26. A sample investigation system as in claim 23, in which the at least one wavelength modifier (WM) accepts electromagnetic radiation comprising wavelengths in the far-IR ranges and outputs electromagnetic radiation with wavelengths in the visible wavelength range.
27. A sample investigation system as in claim 23, in which the at least one wavelength modifier (WM) accepts electromagnetic radiation comprising wavelengths in the mid-IR ranges and outputs electromagnetic radiation with wavelengths in the visible wavelength range.
28. A sample investigation system as in claim 23, in which the at least one wavelength modifier (WM) accepts electromagnetic radiation comprising wavelengths in the near-IR ranges and outputs electromagnetic radiation with wavelengths in the visible wavelength range.
29. A sample investigation system as in claim 23, which further comprises a dispersion optics (DO) for spatially separating different wavelengths present after said stage (STG), and in which said wavelength modifier is placed between a selection from the group consisting of: between said source (LS) and said stage (STG); between said stage (STG) and said dispersive optics (DO); between said dispersive optics (DO) and said detector (PA).
30. A sample investigation system selected from the group consisting of: an ellipsometer; a polarimeter; a reflectometer; and a spectrophotometer; for use in investigation samples with electromagnetic radiation; said system comprising: a source (LS) of electromagnetism; a stage (STG) for supporting a sample; and a detector (PA); said system source (LS) providing electromagnetic radiation in a wavelength range, longer or shorter than said detector elements (DE's) can detect; said system being characterized by the presence of, prior to said detector (PA), at least one wavelength modifier (WM) for accepting electromagnetic radiation of wavelengths outside the range of said detector (PA) said state elements (DE's) can detect, and providing output electromagnetic radiation based thereupon of wavelengths which said solid state elements (DE's) can detect.
31. A sample investigation system as in claim 30 in which the source (LS) provides electromagnetic radiation with wavelengths in a range selected from: ultraviolet; visual; far-infrared; mid-infrared; terahertz.
32. A sample investigation system as in claim 30 in which said detector detects wavelengths in a range selected from: ultraviolet; visual; far-infrared; mid-infrared; terahertz; said selected range being different from that provided by said source (LS).
33. A sample investigation system as in claim 30, in which the source provides wavelengths in a range selected from: far-infrared; mid-infrared; near infrared; and terahertz; and the wavelength modifier provides wavelengths in a range selected from the group consisting of: ultraviolet; and visual.
34. A sample investigation system as in claim 30, in which the source of electromagnetic radiation is selected from the group consisting of: Ar, Xe and He Discharge Lamps in the UV region; Tungsten Filament Lamps in the Visible region; Blackbody radiators, Nernst, and Globars in the Infrared ranges; Hg and Na line producing Lamps in the UV and Visible ranges; lasers in the and visible and IR ranges; and super continuum lasers in wavelength ranges of 400 nm to 18000 nm; and said detector is characterized by a selection from the group consisting of: Golay cells; bolometers; micro-biometers; thermocouples; photoconductive materials; deuterated triglycine sulfate (DTGS); HgCdTe (MCT); LiTaO3; PbSe; PbS; InSb; and silicon, germanium and gallium arsenide solid state devices.
35. A method of investigating a sample comprising the steps of: a) providing: an ellipsometer; a polarimeter; a reflectometer; and a spectrophotometer; for use in investigation samples with electromagnetic radiation; said system comprising: a source (LS) of electromagnetism; a stage (STG) for supporting a sample; and a detector (PA) comprising detector elements (DE's); said system source (LS) providing electromagnetic radiation in a wavelength range, longer or shorter than said detector elements (DE's) can detect; said system being characterized by the presence of, prior to said detector (PA), at least one wavelength modifier (WM) for accepting electromagnetic radiation of wavelengths outside the range of said detector (PA) said state elements (DE's) can detect, and providing output electromagnetic radiation based thereupon of wavelengths which said solid state elements (DE's) can detect; b) placing a sample to be investigated on said stage (STG); c) causing said source (LS) to provide electromagnetic radiation comprising wavelengths said detector elements (DE's) cannot detect, and direct a beam thereof toward said sample; d) causing said wavelength modifier to receive electromagnetic radiation wavelengths different from those which were provided by said source (LS), and modify them to wavelengths said detector elements (DE's) can detect; e) causing said detector elements (DE's) to detect the modified electromagnetic radiation and provide output data; f) analyzing said output data to determine sample characteristics.
36. A method as in claim 35, in which said system further comprises a dispersive optics (DO) which spatially separates different electromagnetic wavelengths, said wavelength modifier (WM) being positioned between said source (LS) and said detector (PA).
37. A method as in claim 36 in which said at least one wavelength modifier is placed between said source (LS) and said stage (STG).
38. A method as in claim 36 in which said at least one wavelength modifier is placed between said stage (STG) and said dispersive optics (DO).
39. A method as in claim 36, in which said at least one wavelength modifier (WM) is positioned between said dispersive optic (DO) and said detector (PA).
40. A system as in claim 23, which comprises at least two wavelength modifiers between said source (LS) or electromagnetic radiation and said detector (PA).
41. A system as in claim 30, which comprises at least two wavelength modifiers between said source (LS) or electromagnetic radiation and said detector (PA).
42. A method as in claim 35, in which said system comprises at least two wavelength modifiers between said source (LS) or electromagnetic radiation and said detector (PA).
43. A method of investigating a sample with electromagnetic radiation of different wavelengths that provided by a source thereof, comprising the steps of: a) providing: an ellipsometer; a polarimeter; a reflectometer; and a spectrophotometer; for use in investigation samples with electromagnetic radiation; said system comprising: a source (LS) of electromagnetism; a stage (STG) for supporting a sample; and a detector (PA) comprising detector elements (DE's); said system source (LS) providing electromagnetic radiation in a wavelength range, longer or shorter than said detector elements (DE's) can detect; said system being characterized by the presence of, prior to said stage (STG), a wavelength modifier (WM); a) placing a sample to be investigated on said stage (STG); b) causing said source (LS) to provide electromagnetic radiation and direct a beam thereof toward said sample; c) causing said wavelength modifier (WM) to receive wavelengths of electromagnetic radiation in a first range as provided by said source (LS) thereof, and emit wavelengths in a modified range; d) causing said detector elements (DE's) to detect the modified electromagnetic radiation wavelengths after interacting with said sample (MS); and e) analyzing said output data to determine sample characteristics.
44. A method as in claim 43, which further comprises a step (c′) between steps c) and d) of placing a second wavelength modifier (WM) between said stage (STG) and said detector (PA) to place wavelengths from said sample (MS) in a range detector elements (DE's) in said detector (PA) can detect.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0332] FIG. 1 demonstrates a number of wavelength ranges in which various multi-channel detectors (DET1) (DET2) (DET3) are designed to handle optimally.
[0333] FIG. 2 shows some present invention combinations of multiple Gratings (G) and/or Dichroic Beam Splitter-Prism Combinations (DBSP), (generically represented as (G/P)), as examples that each produce at least one + or − order spectrum of wavelengths as well as a relatively more energetic Reflected Beam, (eg. Zero Order (ZO) in the case of a Grating), beam of electromagnetic radiation, which is directed to a follow-on Grating (G).
[0334] FIG. 3a shows a grating (G) that reflects an incoming beam (IB) of electromagnetism, and provides a spectrum of wavelengths (λ) in an order thereof, (eg. the first+Order), along with a Zero Order (ZO).
[0335] FIG. 3a′ shows the situation wherein a Reflected (RB) beam is reflected from dichroic beam splitter-prism (DBS-PR) combination at a surface thereof on which is present a Coating, to give it the Dichroic property. Note that a spectrum of at least a + or − order spectrum exits the Prism (P).
[0336] FIG. 4 demonstrates an ellipsometer system, in which the present invention finds very relevant application.
[0337] FIG. 5 shows the use of sequential follow-on Gratings which electromagnetic radiation sequentially caused to encounter.
[0338] FIG. 6 shows the use of beam splitters to direct portions of beams into different detectors which can be optimized to respond to different wavelength ranges.
[0339] FIGS. 7a and 7b show, respectively, typical Intensity vs. position in a beam for a beam of electromagnetic radiation provided by a supercontinuum laser source over a range of about 400-2500 nm, and the same results when a Speckle Reducer is applied to the plot of FIG. 7a.
[0340] FIGS. 8a-8a′″ show a Fly's Eye approach to reducing Speckle.
[0341] FIGS. 8b-8f show various Speckle Reducers.
[0342] FIGS. 9a and 9b are included to show a basic reflectometer or spectrophotometer system, and a basic ellipsometer of polarimeter system, respectively, including one or more Wavelength Modifiers (WM).
[0343] FIG. 9c shows a basic FTIR system which includes a Source of electromagnetic radiation therein.
[0344] FIGS. 9d and 9e show FIGS. 9a and 9b with dispersal optics and Wavelength Modifiers (WM).
[0345] FIG. 9f shows a basic reflectometer or spectrophotometer system, with two wave modifiers (WM) present.
[0346] FIGS. 9g-9i show further examples of ellipsometer systems with Wavelength Modifiers (WM) present therein.
[0347] FIG. 10a is included to show a typical Inventor generated Intensity vs. Wavelength result from a supercontinuum laser, as compared to a typical conventional source of electromagnetic radiation intensity vs. Wavelength.
[0348] FIG. 10b is included to show that recent advances have extended the range of supercontinuum lasers to at least 4400 nm, and even up as high as 18000 nm.
DETAILED DESCRIPTION
[0349] To begin, it is to be appreciated that the Invention Claimed herein is best shown in FIGS. 9F-9J, which concern Wavelength Modifiers (WM) applied in the context of Reflectometers, Spectrophotometers, Ellipsometers and Polarimeter Sample Investigation Systems. Said Wavelength Modifiers (WM) change the Wavelengths of entering electromagnetic radiation, which can be present before or after a Sample (SAM) supporting Stage (STG). However, the Presently Claimed Invention also inseparably involves Sources (LS) and Detectors (PA) of Electromagnetic Radiation. The Drawings herein are adapted from co-pending application Ser. No. 17/300,091 (concerned with Sources (LS) and Detectors (DET)), and are discussed in the order presented therein,
[0350] Turning now to FIG. 1, there are demonstrated a number of wavelength ranges in which various multi-channel detectors (DET1) (DET2) (DET3) are designed to handle optimally. Many additional wavelength ranges could be shown similarly as well, such as a (4) as shown in FIG. 2.
[0351] FIG. 2 shows Source (EM) of electromagnetic wavelengths in the Infrared or Terahertz ranges, a typically present Aperture and a demonstrative use of a Wavelength Modifier (WM), for accepting said Infrared or Terahertz wavelengths and typically providing output wavelengths in a range of wavelengths Solid State Detector (DET) Elements (DE's) (see FIG. 4) can detect. FIG. 2 also shows combinations of multiple Gratings (G) (see FIG. 3a) and/or Dichroic Beam Splitter-Prism Combinations (DBS-RP) (see FIG. 3a′) in FIG. 2), that each produce at least one + or − order spectrum (λλ) of wavelengths, as well as an altered spectral content Reflected (RB/OR) beam of electromagnetic radiation, (eg. a Zero Order (OR) beam as in the case of a Grating (G) or a functionally similar Reflected Beam (RB) in the case of a Dichroic Beam Splitter-Prism Combinations (DBS-PR) (both possibilities indicated as G/P− in FIG. 2). See Reflected Beam (RB) in FIG. 3a′ as regards a combination dichroic beam splitter-prism (DBS-PR) and Zero Order (OR) Beam in FIG. 3a. (Note, the terminology Zero Order (ZO) is not correct in a critical sense where a Dichroic Beam Splitter-Prism Combinations (DBSP), rather than a Grating (G) is applied, even though the results provided are functionally similar). FIG. 2 is a relevant example of a Present Invention System Detector System wherein a Source (EM) of a Beam of electromagnetic radiation (IB) is shown to provide electromagnetic radiation through an Aperture (AP), and impinge on (G/P1). Exiting (G/P1) is a First Range of a + or −, typically first Order spectrum of wavelengths (λ) which proceed, via reflection from a Mirror (M) as shown to Detector (DET1). Also shown is Reflected beam (RB) which reflects from another Mirror (M) and encounters a Dichroic Beam Splitter (DBS), which (DBS) directs a first amount of the entering beam to (G/P3) which disperses it into a range of wavelengths (Δ) which are directed into Detector (DET3). A second amount of the Beam entering the (DBS) exits toward (G/P2) which provides a dispersed range of wavelengths (that are directed into Detector (DET2), and also directs a Reflected Beam (RB″/OR″ to (G/P4) which provides a dispersed range of wavelengths (λ) to Detector (DET4). It is to be understood that FIG. 2 is included to show that the Present Invention can comprise a plurality of Detectors (DET's) each of which comprise a plurality of Solid State Detector Elements (DE's) (see FIG. 4) which can detect wavelengths exiting from said Wavelength Modifier (WM) when relatively longer wavelengths (eg. in the IR or THZ ranges) are entered thereinto, and in which said wavelengths detectable by Solid State Detector Elements (DE's) from said Wavelength Modifier (WM) are guided into said Solid State Detector Elements (DE's) via Beam Splitters (DBS) and/or Prism/Dichroic Beam Splitter Combinations (DBS-PR) (see FIG. 3a′) and/or Gratings (G) (see FIG. 3a).
[0352] FIG. 3a demonstrates a Grating (G) wherein an Input Beam (IB) of electromagnetic radiation is impinged thereonto, with the result that at least one +/− Order Spectrum of wavelengths is produced along with a Zero Order (ZO) beam.
[0353] FIG. 3a′ shows the situation wherein a Reflected (RB) beam is reflected from Dichroic Beam Splitter-Prism (DBS-PR) combination at a surface thereof on which is present a Coating, to give it the Dichroic property. Note that a spectrum of at least a + or − order spectrum exits the Prism (P). A coating (C) is indicated as present on the surface onto which the Input Beam impinges, and serves to form the Dichroic Beam Splitter (DBS). For insight, Dichroic refers to different properties, eg. reflection/transmission of electromagnetic radiation, based on wavelength.
[0354] It is to be understood that the designations of (G/P_) in FIG. 2 is to be interpreted as possibly being either of the systems in FIGS. 3a and 3a′.
[0355] FIG. 4, (which is FIG. 2 taken from U.S. Pat. No. 7,345,762 to Liphardt et al.), is included to demonstrate an ellipsometer system, in which ellipsometer and polarimeter and the like systems the present invention finds very relevant application. When so applied the beam exiting the ellipsometer polarization state analyzer, (ie. (EPCLB) in said FIG. 4), is beneficially considered as being the beam (IB) shown in accompanying FIG. 2. Roughly, Grating (G1) in FIG. 2 corresponds to Dispersive Element (ie. Grating), (DO) in said FIG. 4. Note that FIG. 4 shows an ellipsometer Source (LS) which provides an ellipsometer beam (PPCLB) which has been polarized by interaction with the shown Polarizer (P). Said beam (PPCLB) is then caused to interact with a shown Sample (MS), which is indicated can be a focused beam at that point. A beam reflected from said Sample (MS) can be re-collimated, and then pass through an Analyzer (A) and emerge as beam (EPCLB), before being focused by (FE) onto a Dispersive Element, (eg. a Grating) (DO), which (DO) serves to disperse wavelengths into a Multi-element Detector (PA). One or two Compensators (C) can also be present as shown in the Polarization State Generator or Analyzer or the system associated with the Polarizer and Analyzer respectively. Again, for correspondence, Dispersive Element (DO) is roughly equivalent to Grating (G1) in FIG. 2. Also shown is indication that the Focusing (SSC) and Recollimating (SSC′) lenses can be controlled as to position to optimize intended effects.
[0356] FIG. 5, (from FIG. 9 in U.S. Pat. No. 7,345,762), is included to show the use of sequential follow-on Gratings (eg. G1 and G1′) to arrive at a desired wavelength in a spectrometer system.
[0357] FIG. 6, (taken from FIG. 1a in U.S. Pat. No. 8,169,611), is included to show the use of beam splitters (B1 and B2) to direct portions of beams into different detectors (D1 and D2) which can be optimized to respond to different wavelength ranges. See U.S. Pat. Nos. 7,345,762 and 8,169,611 for more clarification. Said Patents however, do not suggest the present invention directing a Reflected altered spectral content Beam to follow-on beam dispersing elements. FIG. 6 also shows the use of beam splitters to direct portions of beams into different detectors which can be optimized to respond to different wavelength ranges.
[0358] The +/− orders shown in the Drawings can be described generally as being wavelength ranges that are produced when a grating is presented with an incident spectroscopic beam of electromagnetic radiation and in response produces a spectrum of diffracted dispersed wavelengths, and simultaneous with an altered spectral content reflected beam of electromagnetic radiation, typically a Zero-Order beam.
[0359] Continuing, FIG. 7a shows a typical Intensity vs. Position within a Beam Cross-section for a beam of electromagnetic radiation provided by a supercontinuum laser source over a range of about 400 to at least 4400 nm. Note in particular that effects of interactions between coherent components thereof leads to a very inconsistent Intensity plot. It is noted that Speckle can lead to Wavelength instability. Supercontinuum lasers can be applied in the presently Claimed Invention to change Wavelengths provided thereby to wavelengths Solid State Detectors can detect, perhaps in conjunction with Wavelength Filters.
[0360] FIG. 7b shows that application of a “Speckle Reducer” to the beam Intensity profile in FIG. 6 allows a much more stable beam intensity vs. position in a beam profile to be achieved. This much more stable intensity profile is well suited to application in metrology systems such as ellipsometers, polarimeters, reflectometers and reflectometers. It is believed that use of a Supercontinuum Laser Source and Speckle Reducer as described in this Specification is new and novel, particularly in combination with the also described system of Detectors. As mentioned earlier in this Specification, a coherent source leads to interference effects, the present system comprises a speckle diminisher in the form of a selection from the group consisting of: [0361] a multimode fiber; [0362] a beam diffuser; [0363] a fly's-eye beam homogenizer; [0364] a rotating beam diffuser; [0365] a piezoelectric electric crystal driven beam diffuser; [0366] an electronic means to shorten temporal coherence length;
to effectively remove wide changes in intensity very small wavelength ranges, (ie. speckle).
[0367] FIGS. 8a-8a′″ show a Beam Homogenizing approach to reducing Speckle. Note that in FIG. 8a shows that input electromagnetic radiation shown as (EMI), which is of a very uneven intensity but can be transformed into output electromagnetic radiation shown as (EMO), which is of a very even intensity. The system consists of a Beam Expander (BE), a Beam Collimator (BC1), two Fly's Eye lenses (MF1) (MF2), a second Beam Collimator (BC2) applied to focus the Collimated beam exiting (MF2), and a Second Beam Collimator (BC2) which re-collimates the beam presented to it. The energy content of (EM1) has been distributed uniformly by the actions of the Fly's Eye lenses (MF1) and (MF2) as indicated by (EMO). FIGS. 8a′ and 8a″ show typical Fly's Eye lens construction. FIG. 8a′″ is included to indicate how the system of FIG. 8a (BH) can be applied in an Ellipsometer system. At “A” the entering beam from Source (LS) is as shown as (EMI), and “B” the beam energy is distributed as is shown by (EMO), and a Polarization Element (DE) can be applied prior to said beam interacting with Sample (and location (D), with a Detector positioned to monitor a reflected beam from said Sample at location (D) thereon.
[0368] FIGS. 8b-8f show other various Speckle Reducers. FIG. 8b shows a Beam Diffuser Plate with an Input Beam (BI) entering thereinto, and exiting as Diffused Beam (DBO) components. FIG. 8c a simple Fly's Eye lens (FE) which causes a similar effect as does the Beam Diffuser in FIG. 8b when a beam is passed therethrough. FIG. 8d shows the Beam Diffuser (BD) of FIG. 8b attached to a Motor (M) that causes it to rotate in use. An Input Beam (B) is again passed therethrough as shown, and emerges as a Diffused Beam (DBO). FIG. 8e shows a Beam Diffuser (BD) Plate, again as in FIG. 8b, attached to Piezoelectric Drivers (PZ) that are applied to cause the Beam Diffuser (BD) to vibrate vertically and/or horizontally in use. The Fly's Eye (FE) Lens can also be used in the configurations of FIGS. 8d and 8e. FIG. 8f shows an end-on view of a Multimodal Fiber. Note Core region 1 and Outer region 2. In a Multimode Fiber region 1 is a significant portion of region 2. The Region 1 Core is much less prominent in a Single Mode Fiber.
[0369] FIG. 9a is included to show a basic reflectometer or spectrophotometer system comprising:
[0370] a) a source (S) of a beam of electromagnetic radiation;
[0371] b) a stage (STG) for supporting a sample (SAM);
[0372] c) a detector system (DET) of electromagnetism;
said system being distinguished, in the present invention, in that said source (S) of a spectroscopic beam of electromagnetic radiation is a supercontinuum laser that provides an output spectrum as shown FIGS. 7a and preferably 7b. That is, a primary distinguishing aspect of the present invention is the use of a high intensity, highly directional supercontinuum laser to provide electromagnetic radiation. As described earlier with respect to FIG. 2, another aspect of the present invention involves use of detector systems that provide wavelengths of various ranges to detectors that are well suited to detecting said wavelengths.
[0373] FIG. 9b shows the elements of FIG. 9a with polarization state generator (PSG) and polarization state analyzer (PSA) added, to effect an ellipsometer or polarimeter system.
(Note, where more than one Source (S) is spoken of in this Specification and the Claims, the indication of (S) in any relevant Figure is to be interpreted to represent the one in use).
[0374] It is to be understood that the Detector Systems in the forgoing can provide that there be a plurality of Multiple Element arrays be present as in FIG. 2, or that there be a Single Array as in FIG. 4 or a Single Detector as indicated by FIGS. 9a and 9b. FIGS. 9d and 9e show the Detector side of the systems shown in FIGS. 9a and 9b modified to include Detector (DET) Array Elements (DE's). Note that in FIG. 9e the Wave Modifier (WM) is moved from before a Dispersive Optics (DO) to thereafter. In any configuration the Functional Element(s) that provide a measurable electric signal can be Solid State (eg. a CCD Array), or Single Elements, such as a Golay Cell or Bolometer. The later Detectors can be applied in monitoring Infrared and Terahertz Frequency Electromagnetic Radiation. A Golay Cell converts a Temperature change resulting from electromagnetic radiation into an electrically monitorable signal. For instance a distortable diaphram/film can be present that reflects electromagnetic radiation into one or another Photo Cells. A distortion in the shape of diaphram/film in a chamber of a Golay Cell effects electromagnetic radiation directing into a monitoring Photo Cell. A Bolometer operates by converting changes in electric resistance resulting from impinging electromagnetic radiation onto a blackened material. Further, Detectors can include Wavelength Modifiers where applicable, which Wavelength Modifiers serve to change Far Infrared into Near Infrared frequencies/wavelengths, so that less expensive and easier to use Silicon based elements can be used. FIGS. 9a, 9b 9d and 9e identify the Wavelength Modifiers (WM). An example of an Wavelength Modifier that converts longer wavelength to shorter wavelengths is NLIR Nonlinear Infrared Sensors which change Mid-IR Wavelengths to Near Visible Wavelengths. FIG. 9c is included to indicate that the Source (S) of electromagnetic radiation can be part of a Fourier Transform Interferometer (FTIR) system. Shown are the Source (S), a Beam Splitter (BS) and two Mirrors (M1) and (M2). In use Mirror M1 is caused to move up and down as shown. This increases and decreases the path length of the beam from Beam Splitter (BS) thereto. Various wavelengths transmit and are blocked at different positions of Mirror (M1) because of Interference at the Beam Splitter, between the beams between the Beam Splitter (BS) and Mirror (M1) and between the Beam Splitter (BS) and Mirror (M2).
[0375] FIG. 9f shows a basic reflectometer or spectrophotometer system, with two Wavelength Modifiers (WM). Typically only one thereof will be present so two being shown is not to be interpreted as limiting, but note that when only one is present it can be on either side of the stage (STG). When a Wavelength Modifier is present before a Stage (STG), the Sample Investigation System is converted to a system which investigates a Sample (MS) in a different Wavelength range that the Source (LS) of electromagnetic Radiation provides. This can be useful where it is desired to investigate a sample with a very broad range of Wavelengths using the same sample investigation system, without changing Sources (LS) of electromagnetic radiation.
[0376] FIGS. 9g-9i show further examples of ellipsometer systems with Wavelength Modifiers (WM) present therein at various locations after a Stage (STG). The systems are shown to comprise Source (LS) of Spectroscopic electromagnetic radiation, a Polarizer (P), a Compensator (C) (note the (P) and (C) in combination comprise a (PSG)), a Sample (MS) on a Stage (STG), a second Compensator (C′) an Analyzer (A) (note the (C′) and (A) comprise a (PSA)), a Focusing Element (FE), a Dispersive Optics (DO) and a Detector (PA) comprising a plurality of Detector Elements (DE's). In FIG. 9g a Wave Modifier (WM) is present between said Stage (STG) and said Dispersive Optics (DO). FIG. 9h further includes a Beam Splitter (BS) and a Mirror (M) to provide two Detector arrangements, both of which have the Wave Modifier (WM) present between said Stage (STG) and said Dispersive Optics (DO). FIG. 9i differs from FIG. 9g in that the Wave Modifier (WM) is present between the Dispersive Optics (DO) and Detector (PA). Any such arrangement is to be considered within the range of the Present Invention. FIGS. 9g-9i demonstrate the positions of Wave Modifiers (WM) in demonstrative Present Invention systems. Note also, that the FIG. 9g configuration can be present in FIGS. 9h-9i. That is a Wave Modifier (WM) can be present between the Source (LS) and Stage (STG) whether the system is a Reflectometer or Spectrophotometer or Ellipsometer or Polarimeter.
[0377] It is noted that a Polarizer (P), Analyzer (A) or Compensator(s)(C), (as in FIG. 6 or incorporated onto a Polarization State Generator (PSG) or Polarization State Analyzer (PSA) as in FIG. 9b), can be, in use, stationary, or some or all can be caused to rotate.
[0378] FIG. 10a is included to show a typical Inventor of the present invention generated Intensity vs. Wavelength result from a supercontinuum laser when a 0.0325% neutral density filter is present in the path of the supercontinuum laser beam, as compared to a conventional source of electromagnetic radiation intensity vs. Wavelength. Note, the Supercontinuum Laser intensity is very much greater than that of the Conventional Source Spectrum, (shown as about thirty times greater), and to compare their wavelength spectrum characteristics it was necessary that it be greatly attenuated by a 0.0325 neutral density filter.
[0379] FIG. 10b is included to show that progress in Supercontinuum Laser Sources has been made since Parent Applications were filed. Note the greatly expanded Wavelength Range in FIG. 10b as compared to FIG. 10a. It is expected further Wavelength Range expansion will continue and the present invention should be considered in that light. That is the Super Continuum Laser Source Wavelength Ranges shown in FIGS. 10a and 10b are exemplary, not limiting. For instance, Supercontinuum Lasers which provide wavelengths up to 18000 nm are available, though the Intensity at longer wavelengths decreases.
[0380] 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.
