Dual Head X-ray Inspection System

Abstract

To provide a sample inspection system.SOLUTION: The system comprises at least a first inspection unit 12 and a second inspection unit 14 that are positioned above a sample region 22. Each of the at least first and second inspection unit comprises one or more X-ray radiation sources and respective detector arrangements and configured for X-ray fluorescent inspection of a sample. The first and second x-ray inspection units provide first and second inspection properties different in at least one of: the bandwidth of emitted X-ray energy, the energy of emitted X-rays, the spot size of an X-ray beam generated on the sample.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure is in the field of sample inspection systems, and particularly relates to the inspection of samples using X-ray fluorescence. [Background technology]

[0002] Inspection of fabricated samples is an important part of the manufacturing process. Various manufactured articles may be inspected for structural parameters, selected patterns, and material composition. As technology advances, manufactured articles become smaller and the inspection accuracy required increases.

[0003] X-ray fluorescence (XRF) testing provides a non-destructive technique that allows for the detection of the elemental composition of materials. XRF testing utilizes fluorescence caused by the excitation of sample material by X-ray radiation provided by an X-ray source. Atoms of different elements produce characteristic fluorescent emissions unique to each element, allowing for the detection of the material composition of the sample. Energy dispersive X-ray fluorescence (EDXRF) is one of several XRF techniques commonly used in elemental analysis applications, allowing for the detection of various elements present in sample materials.

[0004] Patent Document 1 provides a method and apparatus for inspecting semiconductor wafers for anomalies by accurately measuring elemental concentrations in a target area. The apparatus includes an X-ray imaging subsystem for measuring the elemental composition in the target area of ​​the semiconductor wafer. The apparatus further includes an EDXRF subsystem for measuring the elemental concentration in the target area of ​​the semiconductor wafer. The elemental concentrations may be calibrated by first correlating elemental concentration measurements obtained for the target area using the X-ray imaging system with elemental concentration measurements obtained for the target area using the EDXRF subsystem to receive enhanced, accurate elemental concentration measurements for the target area of ​​the semiconductor wafer.

[0005] Patent Document 2 provides an X-ray optical system, which includes an X-ray source that emits X-rays, a first optical element that conditions the X-rays to form two beams, and at least a second optical element that further conditions at least one of the two beams from the first optical element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 10,697,908 [Patent Document 2] U.S. Patent No. 8,249,220 Summary of the Invention

[0007] A complete inspection of a manufactured sample may often require inspection using two or more different inspection conditions. This may require inspection of the sample using two or more different inspection systems or replacing an inspection unit within an existing inspection system. The present disclosure provides an inspection system configuration that utilizes two or more inspection units simultaneously positioned over a sample area of ​​the inspection system. The two or more inspection units are configured for sample inspection using two or more respective different inspection conditions, allowing for detection of various parameters of the sample.

[0008] Generally, according to some aspects, the present disclosure provides an inspection system including at least a first inspection unit and a second inspection unit positioned above a sample inspection region. Each of the first inspection unit and the second inspection unit includes at least one X-ray radiation source and a respective detector device and is configured for X-ray fluorescence inspection of the sample. According to the present disclosure, the X-ray radiation source of the first inspection unit is configured to emit monochromatic X-ray radiation, and the X-ray radiation source of the second inspection unit is configured to emit polychromatic X-ray radiation.

[0009] This device enables a complete examination of the material composition of a sample by identifying and quantifying elements of the periodic table within the sample. More specifically, the use of polychromatic X-ray radiation in sample examination, e.g., elemental examination, enables the detection of a wide range of elements. However, the use of polychromatic radiation covering a broad band of X-ray energies generates relatively high background radiation that acts as noise. This can limit detection sensitivity for elements present in low concentrations (quantities) in the sample. Alternatively, examination using monochromatic X-ray radiation reduces background noise and thus provides highly sensitive detection of elements that have a fluorescent response to radiation within the irradiation energy band, even at low concentrations. In this regard, examination using monochromatic X-ray radiation as described in this disclosure relates to the use of X-ray radiation within one or more discrete energy bands. Generally, the discrete radiation pattern is typically provided using one or more multilayer optical elements that filter the X-ray radiation provided by the X-ray source. Following filtering by the multilayer optical elements, the X-ray radiation is filtered by one or more bandpass filters that provide one or more discrete energy bands of X-ray radiation directed toward the sample.

[0010] Therefore, the use of monochromatic X-ray radiation for testing allows for high sensitivity to the detection characteristics of selected elements that may be present in a sample in small amounts or at low concentrations, while the use of polychromatic X-ray radiation is known to provide efficient and robust detection of a wide range of elements and their respective detection energies.

[0011] In this context, typical polychromatic X-ray radiation suitable for EDXRF inspection is associated with emission energies ranging from 2.5 keV to 30 keV. A typical polychromatic inspection unit can generally emit radiation within a predetermined profile within such a range. In contrast, as described herein, the term monochromatic inspection is used herein to refer to inspection using one or more discrete bands of relatively narrow energy bandwidth. For example, a monochromatic inspection unit may utilize inspection using one, two, three, or four energy-separated bands with a typical bandwidth of 2 keV, or preferably 1 keV, or more preferably, with a bandwidth of 500 eV. As a result, the emission spectrum of a monochromatic inspection unit can include a selected number of separated emission lines within a broad X-ray spectrum.

[0012] Thus, the inspection system of the present disclosure utilizes inspection systems having generally conventional form factors, eliminates the need for additional inspection systems, and transfers the sample therebetween, allowing for a complete inspection of the material composition of the sample with high spatial resolution along the sample. Complete elemental testing of samples within the form factor of a single testing system, · Sample contamination is significantly reduced by eliminating, or at least greatly reducing, moving parts above the sample area during testing; Common spatial alignment of sample inspections independent of possible manufacturing error variations in stage translation, - Parallel testing is possible, suitable for relatively large, uniform samples; Several advantages are advantageously provided, including but not limited to:

[0013] To enable common mounting of at least a first inspection unit and a second inspection unit above a sample area, the present disclosure further provides a system including: a chassis structure; a sample mount configured to hold one or more samples and enable translation of the one or more samples within the sample area; an inspection system mounting device comprising at least a first support beam and a second support beam attached to the chassis, wherein at least the first support beam and the second support beam include at least a horizontal portion extending above the sample area; and a horizontal beam attached to at least the first support beam and the second support beam and positioned above the sample area, the horizontal beam comprising a mounting device for simultaneously mounting at least a first X-ray fluorescence inspection unit and a second X-ray fluorescence inspection unit and enabling operation of at least the first X-ray fluorescence inspection unit and the second X-ray fluorescence inspection unit by translational movement of the sample within the sample area.

[0014] An arrangement of a horizontal beam mounted on at least a first support beam and a second support beam provides structural stability for the system supporting the weight of at least the first XRF inspection unit and the second XRF inspection unit. Additionally, the configuration of the horizontal beam and its support beams provides unobstructed access to the sample area for inserting, extracting, and otherwise performing various operations on samples within the system.

[0015] Thus, according to a broad aspect, the present disclosure provides a sample inspection system comprising: Provided is a sample inspection system comprising at least a first inspection unit and a second inspection unit positioned above a sample inspection region, each of the at least first inspection unit and the second inspection unit comprising at least one X-ray radiation source and a respective detector device, and configured for X-ray fluorescence inspection of the sample, wherein the at least first X-ray inspection unit and the second X-ray inspection unit provide first and second inspection characteristics that differ in at least one of a bandwidth of emitted X-ray energy, an energy of emitted X-rays, and a spot size of an X-ray beam generated on the sample.

[0016] According to some embodiments, at least one of the first X-ray inspection unit and the second X-ray inspection unit may comprise a source of monochromatic X-ray radiation.

[0017] According to some embodiments, the first X-ray inspection unit and the second X-ray inspection unit may be configured to provide monochromatic X-ray irradiation having one or more central irradiation energies and having a bandwidth of up to 2 keV around the one or more central irradiation energies, and the first inspection unit and the second inspection unit provide first inspection characteristics and second inspection characteristics that differ in at least one of the one or more central irradiation energies of the emitted X-rays and the spot size of the X-ray beam generated on the sample.

[0018] According to some other embodiments, the first inspection unit may be configured to emit X-ray radiation formed from one or more discrete energy bands, and the second inspection unit is configured to emit a continuous spectrum of polychromatic X-ray radiation.

[0019] The first inspection unit may comprise an optical device comprising one or more multi-layer optical elements configured to provide bandpass filtering to X-ray radiation directed thereon, thereby providing an irradiation pattern having one or more discrete energy bands.

[0020] According to some embodiments, at least the first inspection unit and the second inspection unit may be mounted on a common mounting device, the common mounting device comprising a horizontal beam positioned above a dedicated sample area, the horizontal beam being supported by at least two support beams located on different sides of the dedicated sample area.

[0021] The horizontal beam may be supported by two support beams, each formed with a first generally vertical portion extending upward from a bottom frame of the system and a second generally horizontal portion extending horizontally from the first portion and connected to the horizontal beam.

[0022] The support beam may be formed in an inverted "L" shape, with a generally horizontal portion extending above the dedicated sample area, positioning the horizontal beam above the dedicated sample area.

[0023] According to some embodiments, the sample inspection system may further comprise at least one optical microscope unit mounted on the horizontal beam.

[0024] According to some embodiments, the sample inspection system may comprise at least first and second optical microscope units having first and second different focal lengths, respectively, thereby allowing adjustment of the field of view for optical microscopy while avoiding the need to move optical elements during sample inspection.

[0025] According to some embodiments, at least a first inspection unit and a second inspection unit may be attached to the horizontal beam via respective first and second dedicated connectors, the first and second dedicated connectors having a horizontal portion configured to attach the connectors to an upper surface of the horizontal beam and a vertical portion extending along a vertical wall of the horizontal beam, the vertical portion being connectable to a respective one of at least the first inspection unit and the second inspection unit.

[0026] According to some embodiments, at least one of the first connector and the second connector may further include a lower edge (ridge) positioned to lock onto the bottom of the horizontal beam.

[0027] According to some embodiments, the sample inspection system may further comprise a movable sample mount positioned within the sample inspection region and adapted to position a sample for inspection, the movable sample mount having a planar range of movement that enables inspection by at least each of the first inspection unit and the second inspection unit.

[0028] According to some embodiments, at least elements of the first and second testing units are stationary during sample testing, thereby eliminating sample contamination associated with moving elements above the sample.

[0029] According to another broad aspect, the present disclosure provides a system, comprising: a chassis structure; a sample mount configured to hold one or more samples and allow translation of the one or more samples within a sample region; an inspection system mounting apparatus comprising at least a first support beam and a second support beam attached to the chassis, at least the first support beam and the second support beam including at least a horizontal portion extending above the sample area; and a horizontal beam mounted to at least the first support beam and the second support beam and positioned above the sample area, the horizontal beam having a mounting device for simultaneously mounting at least a first X-ray fluorescence inspection unit and a second X-ray fluorescence inspection unit to enable operation of at least the first X-ray fluorescence inspection unit and the second X-ray fluorescence inspection unit by translational movement of a sample within the sample area.

[0030] According to some embodiments, the horizontal beam may further comprise a mounting device for mounting at least a first optical microscope and a second optical microscope in addition to the at least first X-ray fluorescence inspection unit and the second X-ray fluorescence inspection unit.

[0031] According to some embodiments, at least the first support beam and the second support beam may have a vertical portion attached to the chassis transverse to the sample area, with at least the horizontal portion extending from an upper portion of the vertical portion above the sample area, and the mounting device of the horizontal beam being positioned above the sample area.

[0032] According to some embodiments, the mounting device for mounting at least the first X-ray fluorescence inspection unit and the second X-ray fluorescence inspection unit may include attachment points on at least two of the top, side, and bottom surfaces of the horizontal beam.

[0033] According to some embodiments, the system may further comprise at least a first X-ray fluorescence inspection unit and a second X-ray fluorescence inspection unit mounted on respective mounting devices, wherein at least the first X-ray fluorescence inspection unit and the second X-ray fluorescence inspection unit each comprise at least one X-ray radiation source and a respective detector device, wherein the first inspection unit comprises one or more multi-layer radiation filters configured to filter X-ray radiation to provide inspection using one or more discrete energy bands, and wherein the second inspection unit is configured to emit continuous polychromatic X-ray radiation.

[0034] According to some embodiments, the sample mount can include a translation device that allows selective translation of the sample within the sample region, allowing the sample to be selectively positioned under each of the mounting device positions. [Brief explanation of the drawings]

[0035] In order to better understand the subject matter disclosed herein, and to illustrate how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0036] [Figure 1] FIG. 1 is a diagram illustrating a schematic diagram of an inspection system according to some embodiments of the present disclosure. [Figure 2] FIG. 1 illustrates an inspection unit device according to some embodiments of the present disclosure. [Figure 3A] 3A and 3B are diagrams illustrating the inspection sensitivity between polychromatic X-ray inspection (FIG. 3A) and monochromatic X-ray inspection (FIG. 3B) for the detection of a particular element, in accordance with some embodiments of the present disclosure. [Figure 3B] 3A and 3B are diagrams illustrating the inspection sensitivity between polychromatic X-ray inspection (FIG. 3A) and monochromatic X-ray inspection (FIG. 3B) for the detection of a particular element, in accordance with some embodiments of the present disclosure, showing the case of monochromatic X-ray inspection. [Figure 4A]4A and 4B are front and side views of a mounting device for an inspection system and an inspection unit according to some embodiments of the present disclosure. [Figure 4B] 4A and 4B are side views of a diagram showing a front view (FIG. 4A) and a side view (FIG. 4B) of a mounting device of an inspection system and an inspection unit according to some embodiments of the present disclosure. [Figure 5A] 1A-1C are perspective views of a diagram illustrating a test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 5B] 10A-10C are another perspective view of a diagram illustrating a test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 5C] 1A-1C are top views of a diagram illustrating a test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 5D] 1A-1C are exploded views of a diagram illustrating a test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 6A] 10A-10C are perspective views of another test unit and one corresponding type of connector, including different perspective and exploded views, according to some embodiments of the present disclosure. [Figure 6B] FIG. 10 is another perspective view of a diagram illustrating another test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 6C] FIG. 10 is yet another perspective view of a diagram illustrating another test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. [Figure 6D] 10A-10C are exploded views of a diagram illustrating another test unit and one corresponding type of connector, including different perspective views and exploded views, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0037] As discussed above, the present disclosure provides a novel inspection system configuration that enables efficient inspection of a variety of samples utilizing two or more inspection heads within a common system. In this regard, reference is made to FIG. 1 , which illustrates a sample inspection system 100 according to some embodiments. System 100 includes at least a first inspection unit 12 and a second inspection unit 14 mounted on a common beam 30 and positioned to enable inspection of a sample located on a sample mount 20. Sample mount 20 is movable within a sample region 22 using a translation system, exemplified herein by a first linear translation element 24 and a second linear translation element 26.

[0038] Inspection units 12 and 14 are positioned on an inspection system mounting that includes at least one horizontal beam 30 positioned above sample area 22. In this exemplary configuration, horizontal beam 30 is held in position above sample area 22 by first and second support beams 33a and 33b, each of which includes first horizontal portions 34a and 34b. Horizontal portions 34a and 34b of support beams 33a and 33b extend above sample area 22, providing generally unrestricted access to the sample area for placing, removing, and otherwise manipulating a sample on sample area 22.

[0039] 1, the support beams may be formed into an inverted "L" shape including first horizontal portions 34a and 34b and second vertical portions 36a and 36b. The vertical portions 36a and 36b are mounted on a chassis of the system 100 that extends vertically to a selected height above the sample area 22. At the selected height, the horizontal portions 34a and 34b extend from the vertical portions 36a and 36b toward the center of the sample area 22.

[0040] Generally, first inspection unit 12 and second inspection unit 14 are X-ray inspection units configured to provide X-ray illumination onto an illumination spot located beneath the inspection units and to collect response radiation from a sample that may be disposed on a sample mount 20. In addition to first X-ray inspection unit 12 and second X-ray inspection unit 14, system 100 may also include one or more optical microscopes 16. The one or more optical microscopes may be used to collect optical image data of a sample located within system 100 to enable proper alignment of the sample relative to the X-ray inspection units. In some preferred embodiments of the present disclosure, the system may include two or more optical microscopes configured with two or more different selected magnification levels.

[0041] As mentioned above, at least the first inspection unit 12 and the second inspection unit 14 may be X-ray inspection units. In some embodiments of the present disclosure, the X-ray inspection units may be configured to provide energy dispersive X-ray fluorescence (EDXRF) inspection of a sample. Generally, EDXRF is a non-destructive technique for elemental analysis of a sample. This technique is based on analyzing the X-ray fluorescence response of a sample in response to X-ray irradiation. EDXRF allows for the detection of the presence and amount of elements in a sample.

[0042] A conventional EDXRF inspection system typically includes an X-ray source configured to emit X-ray radiation, an appropriate optical system selected to focus the X-ray radiation onto a selected inspection spot, and an X-ray detector configured to collect photons emitted from the sample in response to irradiation by the X-ray radiation. The photons emitted by the sample typically include a mixture of X-ray radiation components emitted by the fluorescent response of different atoms (elements) in the sample, as well as elastically and inelastically scattered photons. The design and operation of X-ray fluorescence (XRF) detectors are well known in the art and therefore will not be described herein. Generally described, the X-ray detector resolves one or more X-ray photon energies from the collected photons and outputs first measurement data formed from electrical signals indicative of the X-ray energy components. The energy of the collected photons is indicative of a characteristic of the sample. The detector can transmit output data to a controller for processing the detected photon energies to provide output data related to the material composition of the sample.

[0043] Thus, as described above, each of the first inspection unit 12 and the second inspection unit 14 includes at least one X-ray radiation source, appropriate optical elements for directing the X-ray radiation to a selected inspection spot on the sample, and one or more detectors. In some embodiments, the first inspection unit 12 and the second inspection unit 14 each include an array of two, three, or four detectors positioned at selected angles to collect radiation emitted from the sample.

[0044] Generally, according to the present disclosure, the first inspection unit 12 and the second inspection unit 14 include one or more inspection units, including a monochromatic X-ray inspection unit. Such monochromatic X-ray inspection units are generally configured to emit X-ray radiation in one or more selected, relatively narrow energy bands (corresponding to one or more wavelength ranges). For example, in some embodiments, the first inspection unit 12 may utilize a monochromatic X-ray inspection unit, and the second inspection unit 14 may utilize a polychromatic X-ray inspection unit operable to emit a relatively broad band of X-ray radiation frequencies. In some other examples, the first inspection unit 12 and the second inspection unit 14 may both utilize monochromatic X-ray inspection units operable with respective first and second X-ray wavelength ranges that differ therebetween and / or first and second different focusing powers that provide irradiation spots of different diameters.

[0045] In this regard, a typical monochromatic X-ray inspection unit may operate to provide irradiation using one or more discrete energy bands of radiation. Such a monochromatic inspection unit may operate to emit radiation within a single, relatively narrow energy band or within two or three relatively narrow energy bands with no overlap therebetween. A monochromatic inspection unit may utilize a monochromatic X-ray source. Alternatively, a monochromatic X-ray inspection unit may utilize a polychromatic X-ray source and an optical device configured to filter radiation emitted from the X-ray source to produce radiation in one or more discrete energy bands. For example, the monochromatic X-ray inspection unit 12 may utilize an optical device including one or more multilayer optical elements having a layered configuration selected to provide predetermined bandpass filtering of the X-ray radiation directed thereat, thereby enabling radiation in one or more selected discrete energy bands to be directed toward the sample.

[0046] Generally, the use of first and second inspection units capable of operating using different X-ray frequency ranges, respectively, allows for tailoring of sample inspection to detect a selected group of elements that may be present in the sample. For example, the use of a typical broadband X-ray source allows for a high photon flow, enabling efficient detection of a wide variety of elements in large quantities. However, the use of broadband X-ray illumination can generate a large number of scattered photons (either elastic or inelastic) that can mask the fluorescent photons generated due to the fluorescent response from specific elements present in low amounts / concentrations. On the other hand, inspection using narrowband X-ray illumination allows for high spatial resolution of inspection, enabling efficient detection of elements present in low concentrations in the sample with an increased signal-to-noise ratio. For example, this can be advantageous for detecting low concentration levels of silver (Ag) in AgSn bumps, where the use of a specific narrow energy band for inspection reduces unwanted scattering and improves the signal-to-noise ratio. Similarly, the use of first and second monochromatic X-ray inspection units operable with first and second different energy bands (wavelength ranges), respectively, and / or first and second different illumination spot characteristics (diameter, shape), allows tailoring of sample inspection for detection of selected groups of elements to provide high resolution inspection.

[0047] Thus, the use of at least first and second inspection units 12, 14 configured to have first and second different x-ray emission characteristics, respectively, allows for increased accuracy and robustness of sample inspection while maintaining a generally similar form factor of the inspection system. Because sample inspection may typically be performed in a clean room, this technique allows for increased inspection output per unit area of ​​the clean room, enabling additional, more sensitive inspections within a given clean room infrastructure.

[0048] In this regard, FIG. 2 illustrates a specific, non-limiting arrangement of at least a first inspection unit 12 and a second inspection unit 14 in an inspection system 100 according to some embodiments of the present disclosure. While FIG. 2 shows the arrangement of the system's units, for simplicity, FIG. 2 does not specifically show the mounting arrangement, including at least one horizontal beam, to which the inspection units are mounted. The arrangement of the units may further include a two-dimensional microscope 16 and a three-dimensional scanner 18, both configured to provide optical inspection of the sample using visual inspection to examine and measure sites for inspection on the sample. The system further includes a sample mount 20 positioned on a movable stage including a height adjuster 28, a Y-axis adjuster 26, and an X-axis adjuster 24, and configured to enable selective translation of the sample according to instructions provided by a computer system or an operator.

[0049] In this exemplary embodiment, the first inspection unit 12 is configured as a monochromatic X-ray inspection unit using an X-ray source 120 configured to emit X-ray radiation in a selected range and an optical device 122. Monochromatic inspection units generally include one or more filtering elements configured to provide bandpass filtering, which provides irradiation in one or more energy bands having bandwidths up to 2 keV, 1 keV, or 500 eV, with separation therebetween. The optical device 122 includes one or more optical elements for focusing the emitted radiation to a selected spot size on the sample. Additionally, the inspection unit 12 includes an array of detectors 126. Generally, the one or more filters may be associated with one or more multilayer optical elements of the optical device 122 or may be formed by separate filters associated with the X-ray source 120.

[0050] Monochromatic illumination by the monochromatic inspection unit 12 is generally characterized by one or more discrete energy bands of X-ray radiation impinging on the sample. Typically, the X-ray source 120 can generate relatively broadband radiation, and the optical device 122 includes one or more multilayer optical elements that provide bandpass filtering of the emitted radiation. The one or more multilayer optical elements may be configured as dichroic optical elements and / or Bragg filters configured to allow transmission (or reflection) of one or more selected energy bands of X-ray radiation. Thus, the monochromatic inspection unit 12 is configured to provide illumination using one or more (e.g., one, two, or three) discrete, non-overlapping energy bands, each having a relatively narrow bandwidth, generally up to 2 keV, or up to 1 keV, or preferably up to 500 eV.

[0051] In some embodiments, the monochromatic inspection unit 12 may include a generally monochromatic X-ray radiation source 120 configured to provide an emission of X-ray radiation having one or more discrete, non-overlapping energy bands, each having a relatively narrow bandwidth. This may be achieved by one or more filters disposed within, but not within, the optics 122 of the X-ray radiation source 120.

[0052] Furthermore, in this exemplary embodiment, the second inspection unit 14 utilizes a broadband X-ray radiation spectrum. To this end, the second inspection unit 14 may utilize an X-ray emission tube 140 configured to emit a large spectrum of X-ray frequencies, an X-ray filter 142, an optics 144 (e.g., polycarpellary optics) for focusing the emitted X-ray radiation to an illumination spot on the sample, and an array of detectors 146.

[0053] Each of the first inspection unit 12 and the second inspection unit 14 is associated with a particular preselected location of an illumination spot. The locations of the first and second illumination spots are typically characterized by selected coordinates of locations on the stage 20, allowing the sample to be oriented to a selected first coordinate location for inspection using the first inspection unit 12 and further allowing the sample to be translated to a second coordinate location for inspection using the second inspection unit 14.

[0054] Also illustrated in FIG. 2 are optical inspection units (microscopes) 16 and 18. In this example, the system can utilize one or more two-dimensional microscopes 16 and three-dimensional scanners 18. Generally, the system can include a first optical inspection unit 16 and a second optical inspection unit 18 configured to provide optical inspection of a sample using first and second different focal lengths, respectively. Thus, the different microscopes can provide at least two different magnifications and fields of view of the sample. Each of the optical microscopes is positioned to image the sample at a selected stage position based on pre-stored coordinates, allowing optical inspection of the sample at selected optical and magnification conditions via translation of the sample. This configuration allows for changing the field of view, magnification, and other optical conditions for imaging while avoiding the need to shift optical elements above the sample. Typically, movement of various elements above the sample in the system can release particles that can contaminate the sample. Thus, the use of at least first and second optical microscopes combined within the inspection system 100 allows for improved optical inspection while reducing the potential for contamination of the sample being inspected.

[0055] The exemplary configuration shown in Figure 2 above can provide various advantages for elemental testing of a sample. As mentioned above, the use of at least first and second X-ray inspection units can enhance sample testing. Figures 3A and 3B show detection spectra associated with several elements detected in a sample. Figure 3A shows a detection spectrum on an AgSn sample collected using a polychromatic X-ray inspection system, while Figure 3B shows a detection spectrum of the same sample collected using a monochromatic X-ray inspection system with a 500 eV bandwidth. As shown in both figures, the Ag signal is generally low relative to various other elements in the sample, including Sn. In Figure 3A, the background radiation around the Ag-related peak is relatively high, which can reduce sensitivity to variations in Ag content or even completely obscure the peak. The use of a monochromatic X-ray inspection system reduces background radiation, as shown in Figure 3B, allowing for improved sensitivity in detecting the Ag peak, or peaks associated with other elements present in small amounts in the sample. This is because the Sn peak is clearly visible when detected with both inspection systems due to the high amount of Sn atoms in the sample.

[0056] It should further be noted that the present disclosure provides an inspection system utilizing at least first and second X-ray inspection units. The above example of FIG. 2 illustrates a system utilizing a multi-color inspection unit 14 and a mono-color inspection unit 12. In this regard, it should be noted that systems according to some embodiments of the present disclosure may utilize a first mono-color inspection unit and a second mono-color inspection unit operable as the first inspection unit 12 and the second inspection unit 14 of the system 100. In such a configuration, at least the first mono-color inspection unit 12 and the second mono-color inspection unit 14 can operate at respective first and second different wavelength ranges and / or respective first and second X-ray beam powers. This configuration enables broadband inspection with reduced noise for selected wavelengths while eliminating the need to shift elements above the sample, thereby reducing sample contamination. Furthermore, as described above, the inspection system of the present disclosure allows for two or more different inspection technologies while maintaining a form factor generally similar to that of a typical inspection system.

[0057] Additionally, the different inspection units, as well as the selected optical elements and operating parameters for the inspection units 12 and 14, provide selected inspection characteristics. For example, the use of a polycapillary optics 144 combined with a polychromatic X-ray source 140, as illustrated in FIG. 2, can provide a relatively high photon flux, while the monochromatic inspection unit 12 operates with a narrowed beam to provide reduced background noise and may be useful for detecting selected predetermined elements. This allows for fast scanning of a sample using the polychromatic inspection unit 14 and marking of selected areas that may require additional testing for selected elements, for which the monochromatic inspection unit 12 may be more suitable. Furthermore, the use of different optical elements selected for the first inspection unit 12 and the second inspection unit 14 allows for the adjustment of selected scanning parameters, enabling direct scanning of the sample while reducing potential contamination by avoiding any moving elements on the sample. For example, selecting a wider scanning beam increases scanning speed but may sacrifice scanning resolution and sensitivity to low concentrations of elements. The use of an additional monochromatic inspection unit allows for a narrower scanning beam at a selected wavelength range to provide accurate data on small features of the sample and elements present in low concentrations.

[0058] Thus, the selected inspection units may include a monochromatic and a polychromatic X-ray inspection unit, two monochromatic X-ray inspection units that operate at different X-ray energies (wavelengths) or with different optical properties (e.g., irradiation spot size), or two polychromatic X-ray inspection units that operate with different optical properties such as spot size. Meanwhile, the polychromatic and monochromatic X-ray inspection units may utilize similar spot sizes. According to the techniques of the present disclosure, it is advantageous for the spot sizes of the first and second inspection units to be different to enable improved scanning and inspection efficiency.

[0059] 4A and 4B show another exemplary view of a system 100 according to some embodiments of the present disclosure. FIG. 4A shows a front view of the system 100, and FIG. 4B shows a side view of the system 100. As shown, the first and second inspection units 12 and 14 and their respective detectors 146, as well as at least one optical microscope 16, are mounted on a common mounting device. The mounting device is formed from a horizontal beam 32 positioned above the sample area 22. Typically, the horizontal beam 32 is shifted laterally from the center of the sample area 22 to position the inspection units in a relatively central position.

[0060] Horizontal beam 32 is supported by at least two support beams 33a and 33b located on different sides of sample area 22. Horizontal beam 32 and the two support beams 33a and 33b may be made from a high-strength material such as granite, steel, ceramic material, reinforced concrete, or other selected material. Support beams 33a and 33b and horizontal beam 32 are mounted to the frame of the system, but may also be mounted directly to the ground to provide stability and reduce vibration and flexibility of the structure given the weight of two or more testing units mounted to horizontal beam 32.

[0061] In some embodiments, the support beams 33a and 33b may have an inverted "L" shape. More specifically, the support beams may include a first vertical portion extending from a bottom end of the system (e.g., positioned on the floor or stable frame of the system) and extending upward to a selected height. The first vertical beams are located at two corners of the system outside the sample area 22. At the selected height, horizontal support beams extend from the first vertical support beam above the sample area. The horizontal support beams support the main horizontal beam 32 and position the horizontal beam 32 above the sample area 22 while providing easy access to the sample area 22 for positioning and removing samples for testing.

[0062] Also shown in FIG. 4A is the basic arrangement of system 100, with support beams 33a and 33b positioned and connected to base structure 40. Base structure 40 may form the system's primary chassis element and may be made from a selected heavy-duty, high-density material, such as granite. Base structure 40 lowers the system's center of mass and reduces the transmission of environmental vibrations to the system. To this end, the base structure rests on a selected surface mounted on vibration-filtering legs. In this example, the base structure rests on and connects to connection unit 42, which is mounted on system legs 44 using vibration-damping connections 43. Additional system legs 44 may be connected to the ground, preferably using mounting screws 46.

[0063] 4B, support beams 33a and 33b are better illustrated showing their inverted "L" shape. More specifically, support beam 33 includes a first vertical support beam 36 that is attached to a corner of base structure 40 using, for example, corner connection units 41 and extends upward to a selected height "h," and a second horizontal beam portion 34 that extends from vertical beam 36 toward the center of the sample area. Vertical beam portion 36 and horizontal beam portion 34 preferably form a single unit having a corner shape. However, in some embodiments, support beams 34 and 36 may be formed from two separate beams with a connection between them.

[0064] 4B also shows a control box 52 containing a cabling arrangement and controllers for the first and second inspection units 12, 14 and the optical microscope 16, with a cabling arrangement 54 typically extending from the control box 52 along the support beam 33 and out of the system 100 to connect to a power grid, one or more computer systems, etc. Also shown is an X-ray source connector 56 configured to supply gas and power to the X-ray sources of the first and second inspection units 12, 14.

[0065] The inspection system chassis may allow for the introduction of selected devices, such as first and second inspection units and corresponding optical microscopes. To this end, the system 100 may include a system chassis formed from at least a chassis base 40, support beams 33a and 33b, and a horizontal beam 32. The sample stage 20 and translation units 22-26 may be disposed on the chassis base 40. Additionally, the chassis system may include a housing (not specifically shown) that allows for inspection operations in a clean room while eliminating the emission of X-ray radiation outside the system housing. The horizontal beam 32 may be formed with a plurality of mounting locations, e.g., in the form of threaded holes, for attaching selected inspection units.

[0066] The first and second inspection units 12, 14, the optical microscope 16, or any additional units may be attached to the horizontal beam via respective connectors. The connectors are formed with a first end configured to attach to the horizontal beam and a second end configured to connect to the respective inspection unit or microscope. In this regard, reference is made to Figures 5A-5D and 6A-6D, which show the connectors of the first and second inspection units.

[0067] 5A shows a second inspection unit 14 including a polychromatic x-ray source 140, a filter 142, a polycapillary optics device 144, and an arrangement of one or more detectors 146. The inspection unit 14 is mounted on a connector 240 configured to mount on a horizontal beam according to some embodiments of the present disclosure. The connector 240, shown from this particular perspective, is shown to include a main plate 244, a top portion 242, and a front portion 247.

[0068] FIG. 5B shows another perspective view of the second test unit 14 and corresponding connector 240, as viewed from the perspective of the horizontal beam 32. As shown, the connector 240 includes a main plate 244 having a groove 248, a top portion 242, a bottom portion 246, and a front portion 247. Also shown is a set of connecting bolts (e.g., screws) 254 that connect the test unit 14 to the connector 240. The set of connecting bolts 254 are shown here connecting the test unit 14 to a surface formed within the groove 248, providing easy access when the test unit is removed from the horizontal beam 32. The top portion includes an array of connecting holes 252 that are generally suitable for sliding onto a selected number of the connecting bolts or for attachment using the connecting bolts after the connector 240 is placed in position on the horizontal beam 32. Also shown in FIG. 5B is a groove 270 located on the beam-facing side of the main plate 244 and a spring lock 280 located on the bottom portion 246.

[0069] Figure 5C shows a top view of the test unit 14 mounted on the connector 240. This view shows the top portion 242 and respective connection holes 252, the side portion 247 and the bottom portion 246. Figure 5D shows an exploded view showing the test unit 14, dedicated test unit mount side portion 260, and connector 240 separated therebetween, as well as the additional elements shown in Figures 5A-5C.

[0070] 6A shows a first inspection unit 12 mounted on a corresponding connector 340. In this example, the first inspection unit 12 utilizes an X-ray source 120, an optical arrangement 122, and a set of detectors 126, and is configured to provide irradiation with one or more discrete (and generally non-overlapping) energy bands of X-ray irradiation. The connector 340 is illustrated to include a main plate 344, a top portion 342, a side portion 347, and a main plate aperture 348. The top portion includes a particular hole arrangement 352 generally similar to the top portion 242 of the connector 240. In this example, the inspection unit is connected to the connector 340 using bolts 352 at the top surface of the aperture 348.

[0071] 6B and 6C show the first inspection unit 12 and corresponding connector 340 from additional perspectives. FIG. 6D shows an exploded view of the inspection unit 12 and connector 340. The inspection unit 12 may be connected to the connection plate 360 ​​using bolts 364 and washers 366, and the connection plate may be connected to the connector 340 using bolts 352. The connector may also include an array of grooves 370 located on the beam side of the main plate 344.

[0072] In general, the horizontal plate 32 of the system 100 according to the present disclosure may be configured to allow mounting of first and second inspection units in several selected, interchangeable locations. The horizontal beam 32 may be configured with drilled holes for bolts on its top, bottom, and sides in a selected, generally repeating pattern. The connector 240 or 340 is configured with a main plate 244, 344 facing the vertical wall along the side of the horizontal beam 32 and an upper portion 242, 342 configured to mount to the upper side of the horizontal beam. In some embodiments, as illustrated in FIGS. 5A-5D and 6A-6D, the connector may include grooves or bolt holes 270, 370 in the main plate 244, 344 to securely position the connector at a selected location along the horizontal beam 32.

[0073] The grooves 270, 370 may be formed as small notches extending outward from the main plates 244, 344 or inward relative to the surface of the main plates 244, 344. The grooves 270, 370 are preferably configured to follow corresponding opposing grooves on the vertical wall of the horizontal beam 32 to properly position the connector. In some embodiments, the grooves 270, 370 may be formed as holes suitable for connecting to the horizontal beam using one or more bolts.

[0074] In general, however, the connectors 240, 340 may be securely connected to the horizontal beam 32 using one or more bolts in the top portion of the connectors 242, 342. The top portion 242, 342 is generally disposed above the horizontal beam and includes an array of holes 252, 352 for a selected number of bolts to secure the connectors 240, 340 in place. In some embodiments, or in some connectors such as those illustrated in FIGS. 5A-5D , the connectors may also include a bottom portion 246 that includes a spring locking mechanism that allows for further attachment of the connector to the horizontal beam 32.

[0075] In general, the configuration of the connectors 240, 340 and the first and second inspection units and the horizontal beam carrying the inspection units is configured to provide simple installation while maintaining the inspection units 12, 14 in a stationary position within the system. Such a stationary position allows for repeatability in scanning different samples, since the field of view and illumination spot position of each of the inspection units 12, 14 are fixed in space. Furthermore, by maintaining the inspection units 12, 14 and the optical microscope 16 stationary during inspection, avoiding the need for moving elements during inspection, sample contamination due to the release of particles, such as oil particles, within the inspection system is eliminated, or at least significantly reduced.

[0076] Thus, as described above, the present disclosure provides an inspection system configured to operate with two or more inspection units, generally configured for X-ray inspection of samples. The use of two or more inspection units, each operable with two or more different inspection characteristics (e.g., radiation bandwidth, radiation energy range, illumination spot size, etc.), can provide complete inspection of various samples, with one inspection unit performing a broad inspection for (i) a wide field of view or (ii) a strong elemental signal based on high concentration, and another inspection unit targeting (i) a pinpoint with a smaller spot size or (ii) a precise wavelength range for inspection of low-concentration elements. Thus, the present technology can save expensive cleanroom space and operating time, providing near-complete inspection of complex samples within a single inspection system form factor.

[0077] It should be noted that the various features described in the various embodiments can be combined according to all possible technical combinations.

[0078] It is to be understood that the present invention is not limited in its application to the details set forth in the description contained herein or in the drawings. The present invention is capable of other embodiments and of being practiced and carried out in various ways. Accordingly, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Those skilled in the art will therefore appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out some of the purposes of the subject matter of this disclosure.

[0079] Those skilled in the art will readily appreciate that various modifications and changes can be made to the embodiments of the present invention, as described above, without departing from the scope thereof as defined in and by the appended claims.

Claims

1. 1. A sample inspection system, comprising: at least a first inspection unit and a second inspection unit positioned above the sample region, each of the at least first inspection unit and the second inspection unit comprising at least one X-ray radiation source and a respective detector device and configured for X-ray fluorescence inspection of the sample; the at least first and second X-ray inspection units provide first and second inspection characteristics that differ in at least one of a bandwidth of emitted X-ray energy, an energy of emitted X-rays, and a spot size of an X-ray beam generated on the sample; the at least first and second inspection units are mounted on a common mounting device, the common mounting device including a horizontal beam positioned above the sample area, the horizontal beam being supported by at least two support beams located on different sides of the sample area; Sample inspection system.

2. The sample inspection system of claim 1 , wherein at least one of the first X-ray inspection unit or the second X-ray inspection unit includes at least one source of monochromatic X-ray radiation.

3. 2. The sample inspection system of claim 1, wherein the first X-ray inspection unit and the second X-ray inspection unit are configured to provide monochromatic X-ray irradiation having one or more central irradiation energies, the one or more central irradiation energies having a bandwidth of up to 2 keV around the one or more central irradiation energies, and the first inspection unit and the second inspection unit provide first and second inspection characteristics that differ in at least one of the one or more central irradiation energies of emitted X-rays and a spot size of an X-ray beam generated on a sample.

4. 10. The sample inspection system of claim 1, wherein the first inspection unit is configured to emit X-ray radiation formed from one or more discrete energy bands, and the second inspection unit is configured to emit a continuous spectrum of polychromatic X-ray radiation.

5. 5. The sample inspection system of claim 4, wherein the first inspection unit comprises an optical device comprising one or more multilayer optical elements configured to provide bandpass filtering to X-ray radiation directed thereon, thereby providing an irradiation pattern having one or more discrete energy bands.

6. 2. The sample inspection system of claim 1, wherein the horizontal beam is supported by the at least two support beams, each of the support beams having a first, substantially vertical, portion extending upward from a bottom frame of the sample inspection system and a second, substantially horizontal, portion extending horizontally from the first portion and connected to the horizontal beam.

7. 2. The sample inspection system of claim 1, wherein the support beam is formed as an inverted "L" shape with a generally horizontal portion extending above the sample area, positioning the horizontal beam above the sample area.

8. 10. The sample inspection system of claim 1, comprising at least a first optical microscope unit and a second optical microscope unit having first and second different focal lengths, respectively, thereby enabling adjustment of the field of view for optical microscopy while avoiding the need to move optical elements during sample inspection.

9. 2. The sample inspection system of claim 1, wherein the at least first and second inspection units are attached to the horizontal beam via respective first and second dedicated connectors, the first and second dedicated connectors comprising a horizontal portion configured to attach the first and second dedicated connectors to an upper surface of the horizontal beam and a vertical portion extending along a vertical wall of the horizontal beam, the vertical portion being connectable to at least each of the first and second inspection units.

10. 10. The sample inspection system of claim 9, wherein at least one of the first dedicated connector and the second dedicated connector further comprises a lower edge positioned to lock onto a bottom of the horizontal beam.

11. 2. The sample inspection system of claim 1, further comprising a movable sample stage positioned within the sample region and adapted to position a sample for inspection, the movable sample stage having a planar range of movement that enables inspection by at least each of the first inspection unit and the second inspection unit.

12. 10. The sample inspection system of claim 1, wherein elements of the at least first and second inspection units are stationary during sample inspection, thereby eliminating sample contamination associated with elements moving above the sample.

13. A sample inspection system, comprising: a chassis structure; a sample mount configured to hold one or more samples and allow translation of the one or more samples within a sample region; an inspection system mounting apparatus comprising at least a first support beam and a second support beam attached to the chassis structure, the at least first support beam and the second support beam including at least a horizontal portion extending above the sample area; a horizontal beam mounted to the at least first and second support beams and positioned above the sample area, the horizontal beam comprising a mounting device for simultaneously mounting at least a first XRF inspection unit and a second XRF inspection unit to enable movement of the at least first and second XRF inspection units by translational movement of a sample within the sample area; A sample inspection system, including:

14. 14. The sample inspection system of claim 13, wherein the at least first and second support beams have vertical portions attached to the chassis structure transversely to the sample area, the at least horizontal portion extending from an upper portion of the vertical portion above the sample area, and the mounting device of the horizontal beam being positioned above the sample area.

15. 14. The sample inspection system of claim 13, wherein the mounting device for mounting at least a first XRF inspection unit and a second XRF inspection unit comprises attachment points on at least two of a top surface, a side surface, and a bottom surface of the horizontal beam.

16. 14. The sample inspection system of claim 13, further comprising at least a first X-ray fluorescence inspection unit and a second X-ray fluorescence inspection unit mounted to the mounting device, each of the at least first X-ray fluorescence inspection unit and second X-ray fluorescence inspection unit comprising at least one X-ray radiation source and a respective detector device, the first X-ray fluorescence inspection unit comprising one or more multi-layer radiation filters configured to filter X-ray radiation to provide inspection using one or more discrete energy bands, and the second X-ray fluorescence inspection unit configured to emit continuous polychromatic X-ray radiation.

17. 14. The sample inspection system of claim 13, wherein the sample mount comprises a translation device that allows selective translation of the sample within the sample region, allowing the sample to be selectively positioned under each mounting device location.

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