BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart schematically presenting a preferred form of the invention, wherein a region of interest 10 on a specimen is scanned to collect spectra from a set of pixels 12 (step A); the spectra are then condensed by combining the emission counts in adjacent energy intervals (channels) within the spectra (step B), and/or by combining the spectra of adjacent pixels (step C); the condensed spectra are then analyzed to identify probable components present at the pixels (step D); the spectra of the pixels having similar probable components (and proportions thereof) are then combined (step E); the resulting spectra are cross-referenced via reference spectra to determine their actual components (step F); and the results are then output to the analyst (step G).
FIG. 2 is an image (e.g., an electron image) of a region of interest on a specimen.
FIGS. 3A-3C illustrate exemplary output that might be obtained from the invention after 10 seconds of data collection and analysis of the region of interest of FIG. 2, wherein FIG. 3A illustrates probability maps wherein the density (darkness) or a pixel/region depicts the probability that one of three probable components is present at that pixel, FIG. 3B depicts corresponding binary maps wherein a darkened pixel indicates that a certain probable component is dominant (most probable) at that pixel (and conversely a white pixel indicates that a certain probable component is unlikely at that pixel), and FIG. 3C illustrates the reference spectra obtained when the pixels of each of FIGS. 3A-3C each have their respective spectra combined and cross-referenced versus a reference library of spectra.
FIGS. 4A-4C illustrate exemplary output that might be obtained from the invention after 30 seconds of data collection and analysis of the region of interest of FIG. 2, with an additional component (Cu in addition to Fe, Cu—Zn, and Ag—Cd) being identified here owing to the larger data cube (with 30 seconds of data rather than merely 10).
FIG. 5 illustrates an exemplary final report that might be generated and presented to an analyst after data collection is completed on the region of interest of FIG. 2 (e.g., after 60 seconds of data collection), with an image of the region of interest being presented along with corresponding binary images showing where each predicted component is dominant, and also with the reference spectra obtained when the pixels corresponding to each of the dominant components each have their respective spectra combined and cross-referenced versus a reference library of spectra.
DETAILED DESCRIPTION OF THE PREFERRED VERSIONS OF THE INVENTION
To expand on the foregoing Summary, FIGS. 2-5 show output that might be obtained from an exemplary version of the invention. An analyst can load a desired specimen into a spectrometer of the desired form, e.g., a spectrometer for energy-dispersive X-ray spectrometry (EDS), FT-IR and/or Raman spectrometry, electron energy-loss spectrometry (EELS), secondary ion mass spectrometry (SIMS), auger electron spectrometry, or any other spectrometer which collects specimen characteristics (such as mass, energy or wavenumber emissions) on a pixel-by-pixel basis. The analyst might then input desired measurement settings, such as the location and size of the region of interest (e.g., 256×256 pixels, 1024×1024 pixels, etc.), the “frame” or “exposure” time over which emissions are to be captured from each pixel, the number of times the set of pixels is to be scanned, and so forth. Once data collection begins, the collected data can periodically be analyzed to provide output to the analyst as data collection proceeds. For example, after each scan over the region of interest, or after some time interval (e.g., 10 seconds) has expired, the system might analyze the data that has thus far been collected and provide output to the analyst so that the analyst might begin formulating conclusions and future actions while data acquisition proceeds. Any conclusions based on preliminary data analysis results can be revised as data collection proceeds, and as updated or final analysis results are made available to the analyst.
To illustrate this process in greater depth, FIGS. 3A-3C illustrate exemplary results from the specimen of FIG. 2 after data have been collected for 10 seconds (as in step A in FIG. 1), condensed (steps B and/or C in FIG. 1), and analyzed and output (steps D-G in FIG. 1). The step of condensing the collected spectra—i.e., “energy binning” (combining adjacent energy intervals/channels) and/or “spatially binning” (combining the spectra of adjacent pixels) the spectra—is optional, but unless the data cube is reduced by these or similar steps, it is difficult to process the collected data with sufficient speed that meaningful analysis results can be supplied during the course of data collection. As discussed previously, during analysis, the spectra of the various pixels are analyzed for their correlation to determine some set of proposed component spectra, wherein the proposed component spectra appear to combine in varying proportions to result in the measured spectra at the various pixels. In FIGS. 3A-3C, three proposed components—Cu—Zn (copper-zinc solder), Ag—Cd (silver-cadmium solder), and Fe (iron)—appear probable based on the data cube collected thus far, and FIG. 3A illustrates calculated probability maps wherein the pixel density (pixel darkness) represents the probability that a specified one of the probable components is present at a given pixel. FIG. 3B then depicts maps corresponding to those of FIG. 3A, but wherein probabilities are presented in binary form, with a dark pixel indicating that a certain probable component is dominant (most probable) at that pixel, and conversely a white pixel indicating that a certain probable component is unlikely at that pixel. The spectra of FIG. 3C are then obtained if the measured spectra corresponding to each of the component pixels—i.e., the dark pixels for each of the Cu—Zn, Ag—Cd, and Fe binary maps of FIG. 3B—are combined, and then cross-referenced versus libraries of reference spectra.
FIGS. 4A-4C then show corresponding proposed components, probability maps, and spectra after 30 seconds of data collection. At this point, the data cube is larger, and sufficient spectra are present which indicate a the presence of a distinct fourth probable component (Cu) that this component now appears present in the specimen.
FIG. 5 then presents a view of a report that might be presented to an analyst, with the report here showing the image of the specimen, the binary probability maps for each probable component (which effectively amount to maps of where each probable component is the dominant component in the specimen), and the corresponding reference spectra. This report might be presented to the analyst after all data collection is complete, and/or it could be presented at some earlier time (e.g., after some period or time or number of data collection scans).
It should be understood that the versions of the invention described above are merely exemplary, and the invention is not intended to be limited to these versions. Rather, the scope of rights to the invention is limited only by the claims set out below, and the invention encompasses all different versions that fall literally or equivalently within the scope of these claims.
Patent Application
20080027657
