Calibration method and device for X-ray fluorescence spectrometry equipment

Abstract

The present application is applicable to the field of equipment calibration technology, and provides a calibration method and device for X-ray fluorescence spectrometry analysis equipment, the method comprising: calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B element zone and the X-ray fluorescence spectrum of the elements in the B element zone, and recording the peak position intensity of the B element zone as the reference intensity; calibrating the reference coordinates of the light spot according to the return signal of the detector when the reference coordinates of the light spot coincide with the test point of the B zone, the test ratio and the reference intensity. The present application calibrates the peak position of the detector for the B element zone, and based on the reference intensity, uses the area ratio of each B element interval to accurately calibrate the position of the light spot, thereby realizing the joint calibration of the optical path, peak position and intensity.

Description

Technical Field

[0001] The present application belongs to the technical field of equipment calibration, and in particular, relates to a calibration method and device for X-ray fluorescence spectrometry equipment. Background Art

[0002] XRF detection technology, as a mature and reliable material composition and content analysis technology, has been widely used in the semiconductor field. XRF technology usually includes four parts: X-ray light source, optical focusing device, sample carrier to be tested and detector. The light source can emit X-rays of specific bands by exciting targets of different elements with different energies. These rays are focused on specific areas on the sample surface through optical focusing devices to stimulate the secondary X-ray fluorescence of the sample. The detector analyzes the energy spectrum and intensity of these fluorescence to obtain the material composition and related element content of the sample.

[0003] Compared with the commonly used XRF technology, XRF equipment in the semiconductor testing field often requires a small detection area (spot size of dozens to hundreds), a high degree of mechanical automation (manipulators move samples up and down to be tested), a high degree of standardization of test products (standard wafers of 4 inches to 12 inches in size), and light sources of multiple energy ranges (multiple target materials to cope with X-ray fluorescence excitation of different sample elements).

[0004] However, in the prior art, the calibration of XRF analysis equipment has the following problems.

[0005] Optical path calibration:

[0006] (1) Manual debugging and calibration are required in the early stage, and the system cannot be calibrated in real time. Later maintenance requires human intervention, which is often time-consuming and repeatability cannot be guaranteed. Moreover, if the laser energy is too high, it may damage the sample.

[0007] (2) This positioning is relatively rough and lacks accuracy through visual inspection. Moreover, due to the size of the fluorescent photosensitive unit, the visible light spot area may be larger than the actual X-ray spot area, affecting the precise positioning of the spot.

[0008] (3) The intensity distribution of the light spot itself and the size of the sample detection area have a high computational requirement. In addition, the light spot position needs to be roughly known in order to place the light spot in a specific graphic area for measurement. Since the light spot of semiconductor measurement equipment is small (a diameter of tens of microns), initial positioning is difficult.

[0009] System calibration:

[0010] The system calibration process often requires manual replacement of multiple samples for calibration, which is time-consuming and has poor reliability. It is easy to introduce manual operation errors and it is impossible to obtain real-time machine data.

[0011] In addition, existing technologies usually separate optical path calibration from system calibration, which is inefficient and unable to detect machine conditions in real time to achieve automated calibration.

[0012] Therefore, how to provide a high-precision calibration method for X-ray fluorescence spectrometry equipment that combines optical path and system calibration has become an urgent problem to be solved in the industry. This problem is also the key to ensuring the accuracy and stability of the machine. Summary of the invention

[0013] The embodiments of the present application provide a calibration method and apparatus for an X-ray fluorescence spectrometer, which can solve the problems of errors easily generated by manual operation and low efficiency of executing optical path calibration and system calibration respectively.

[0014] In a first aspect, an embodiment of the present application provides a calibration method for an X-ray fluorescence spectrometry analysis device, wherein the calibration is performed using a calibration wafer; the calibration wafer includes a B calibration area, the B calibration area includes at least two B element areas consisting of elements with known X-ray fluorescence spectra, and the boundaries of the B element areas pass through a preset B area test point; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with a reference coordinate, and the detector of the analysis device acquires the X-ray fluorescence spectrum of the element at the light spot; within the light spot area centered on the B area test point, the area ratio of the B element area is a preset test ratio;

[0015] The calibration method comprises:

[0016] Calibrate the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the elements in the B element area, and record the peak position intensity of the B element area as the reference intensity;

[0017] The reference coordinates of the light spot are calibrated according to the detector return signal, the test ratio and the reference intensity when the reference coordinates of the light spot coincide with the test point of zone B.

[0018] The above method calibrates the detector peak position for the B element area, and based on the reference intensity, uses the area ratio of each B element interval to accurately calibrate the spot position, thereby achieving joint calibration of the optical path, peak position and intensity.

[0019] Ideally, the reference coordinates of the light spot are consistent with the real coordinates. When the reference coordinates of the light spot coincide with the test point in zone B, the ratio of the intensity of the signal returned by the detector to the reference intensity of any of the B element zones should be consistent with the area ratio of the B element zone within the light spot region centered at the test point in zone B, that is, the test ratio. Therefore, it is only necessary to adjust the position of the light spot to meet the aforementioned ratio consistency condition. It can be considered that the reference coordinates of the light spot should be the real coordinates of the test point in zone B at this time, thereby calibrating the optical path. Considering that the detector accuracy of XRF is quite sensitive, this optical path calibration has better accuracy than the traditional method.

[0020] In a possible implementation manner of the first aspect, the calibration wafer further includes a C calibration area, the C calibration area including a C element area composed of elements with known X-ray fluorescence spectra; an area of ​​at least one of the C element areas and an area of ​​the light spot satisfy a preset area equivalence condition;

[0021] After the step of calibrating the reference coordinates of the light spot according to the detector return signal, the test ratio and the reference intensity when the reference coordinates of the light spot coincide with the test point of zone B, the step further includes:

[0022] Determine the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establish or adjust the light intensity distribution function according to the light intensity distribution of the light spot;

[0023] The light intensity distribution function is used to correct the intensity of the signal returned by the detector to a value that is positively correlated with the irradiation area of ​​the light spot.

[0024] The above method uses the detector return signal that partially overlaps with the C element area to build a model to obtain the light intensity distribution within the light spot, and corrects the detector return signal based on the light intensity distribution within the light spot so that when the light spot irradiation area is the same, the intensity of the return signal in each area is consistent, which provides convenience for the testing of small-size samples.

[0025] In a possible implementation manner of the first aspect, the step of recording the peak intensity of the B element region as the reference intensity includes:

[0026] Move the light source in a direction perpendicular to the calibration wafer, and record the coordinate of the light source when the intensity of the return signal of the detector is greater than a first preset intensity, which is recorded as a Z coordinate;

[0027] If it is determined that the Z coordinates of different B element areas are the same, the return signal intensity of the detector when the light source is at the Z coordinate and the light spot is located in the B element area is recorded as the reference intensity of the B element area; otherwise, the optical path of the analysis device is calibrated by a preset method.

[0028] The above method verifies the system optical path through the Z coordinate. When the optical path is focused normally, the Z coordinate of the focus position of the B element area of ​​different elements should be the same. Therefore, verifying the optical path through the Z coordinate can reliably eliminate the optical path problem and provide a good equipment foundation for the calibration of other parameters.

[0029] In a possible implementation manner of the first aspect, the calibration wafer further includes a D calibration area, wherein the D calibration area includes at least two D element areas of different thicknesses composed of elements with known X-ray fluorescence spectra;

[0030] After the step of determining the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establishing or adjusting the light intensity distribution function according to the light intensity distribution of the light spot, the method further includes:

[0031] Establishing or adjusting a film thickness regression function according to the return signal intensity of the detector when the light spot is in the D element region and the thickness of the D element region;

[0032] The film thickness regression function is a function of the sample film thickness at the light spot and the intensity of the signal returned by the detector.

[0033] The above method establishes or adjusts the film thickness regression function through the return signal of the detector in the D element zone with different thicknesses, which can provide the thickness information of the sample more accurately in actual testing, which is conducive to improving the accuracy and reliability of the test results, especially the test results in the semiconductor field.

[0034] In a possible implementation manner of the first aspect, the calibration wafer further includes an A calibration area, the A calibration area includes an A element area composed of elements with known X-ray fluorescence spectra; the A element area includes two rectangular element areas orthogonal in the long axis direction, and the width of the rectangular element area is of the same order of magnitude as the size of the light spot;

[0035] Before the step of calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the elements in the B element area, and recording the peak position intensity of the B element area as the reference intensity, the step further includes:

[0036] Move the light spot whose reference coordinate is located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the intensity of the return signal of the detector is greater than the second preset intensity;

[0037] The reference coordinates of the light spot are corrected according to the first coordinates and the second coordinates.

[0038] The above method sets an orthogonal rectangular element area so that the detector returns a stronger signal when the light spot is located in the rectangular element area. Therefore, even if the reference coordinates of the light spot are greatly different from the actual coordinates, the first coordinates and the second coordinates for correcting the reference coordinates can still be accurately given by translating the light spot, thereby achieving the effect of coarse adjustment of the reference coordinates of the light spot.

[0039] In a possible implementation manner of the first aspect, after the step of correcting the reference coordinates of the light spot according to the first coordinates and the second coordinates, the method further includes:

[0040] Return to the step of moving the light spot with the reference coordinate located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the return signal intensity of the detector is greater than the second preset intensity, until the values ​​of the first coordinate and the second coordinate are less than the width of the rectangular element area.

[0041] The above method balances the contradiction between the width of the rectangular element area, that is, the difficulty of correction and the accuracy of correction, by repeatedly iteratively correcting the reference coordinates of the light spot. Although the width of the rectangular element area of ​​the same order of magnitude as the light spot size can make it easier to find a stronger return signal from the detector, the adjustment accuracy of the reference coordinates is limited by the width of the rectangular element area and may not be accurate enough. Therefore, this problem can be overcome through the iterative correction method, thereby ensuring the effectiveness of the coarse adjustment of the reference coordinates of the light spot.

[0042] In a possible implementation of the first aspect, if the light spot is an elliptical light spot, the major axis and / or minor axis of the light spot ellipse centered at the test point in zone B coincides with the boundary of the B element zone; if the light spot is a circular light spot, any radius or diameter of the circular light spot centered at the test point in zone B coincides with the boundary of the B element zone.

[0043] The above method provides an optimal B element zone boundary setting scheme for elliptical spot and circular spot respectively. This setting can reduce the difficulty of preparing the B element zone of the calibration wafer while ensuring the calibration effect.

[0044] In a second aspect, an embodiment of the present application provides a calibration device for a semiconductor X-ray fluorescence spectrometer analysis device, which implements calibration using a calibration wafer; the calibration wafer includes a B calibration area, the B calibration area includes at least two B element areas composed of elements with known X-ray fluorescence spectra, and the boundary of the B element area passes through a preset B area test point; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with a reference coordinate, and the detector of the analysis device acquires the X-ray fluorescence spectrum of the element at the light spot; within the light spot area centered on the B area test point, the area ratio of the B element area is a preset test ratio;

[0045] The calibration device comprises:

[0046] A B-zone peak position module, used to calibrate the peak position of the detector according to the return signal of the detector when the light spot is located in the B-zone and the X-ray fluorescence spectrum of the elements in the B-zone, and record the peak position intensity of the B-zone as the reference intensity;

[0047] The B-zone coordinate module is used to calibrate the reference coordinate of the light spot according to the detector return signal, the test ratio and the reference intensity when the reference coordinate of the light spot coincides with the test point of the B zone.

[0048] In a third aspect, an embodiment of the present application provides a terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the calibration method of the X-ray fluorescence spectrometry analysis device described in any one of the first aspects above is implemented.

[0049] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the calibration method of the X-ray fluorescence spectrometry analysis device described in any one of the first aspects above is implemented.

[0050] In a fifth aspect, an embodiment of the present application provides a computer program product, which, when executed on a terminal device, enables the terminal device to execute the calibration method for an X-ray fluorescence spectrometer as described in any one of the first aspects above.

[0051] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 It is a schematic flow chart of a calibration method of an X-ray fluorescence spectrometer provided in an embodiment of the present application;

[0054] Figure 2 It is a schematic diagram of the structure of a calibration device for a semiconductor X-ray fluorescence spectrometer provided in an embodiment of the present application;

[0055] Figure 3 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application;

[0056] Figure 4 is a schematic structural diagram of a calibration wafer provided in an embodiment of the present application;

[0057] Figure 5 It is a flowchart of an optional calibration solution provided in an embodiment of the present application;

[0058] Figure 6 is a schematic structural diagram of a semiconductor X-ray fluorescence spectrometer provided in an embodiment of the present application;

[0059] Figure 7 is a schematic diagram of a first position relationship between a light source and a detector provided in an embodiment of the present application;

[0060] Figure 8 is a schematic diagram of a second position relationship between a light source and a detector provided in an embodiment of the present application;

[0061] Fig. 9 It is a schematic diagram of the coarse adjustment of the reference coordinates of the light spot in the A calibration area provided in an embodiment of the present application;

[0062] Fig.10 It is a schematic diagram of the peak position calibration of the B calibration area and the fine adjustment of the light spot reference coordinates provided in the embodiment of the present application;

[0063] Fig.11 is a schematic diagram of the size of the C element area of ​​the C calibration area provided in the embodiment of the present application;

[0064] Fig.12 It is a schematic diagram of the partial overlap between the C calibration area light spot and the C element area provided in the embodiment of the present application;

[0065] Fig.13 is a schematic diagram of the thickness of the D element area of ​​the D calibration area provided in an embodiment of the present application;

[0066] Fig.14 It is a fitting schematic diagram of the film thickness regression function of the D calibration area provided in the embodiment of the present application.

[0067] Reference numerals:

[0068] Peak module 201 in zone B;

[0069] B zone coordinate module 202;

[0070] Wafer transfer box 501;

[0071] Calibration wafer 5021 in a first position;

[0072] Calibration wafer 5022 in a second position;

[0073] Calibration wafer 5023 in a third position;

[0074] Manipulator 503;

[0075] Wafer position calibration device 504;

[0076] Mechanical movable table 505;

[0077] Measurement area 506;

[0078] X-ray detector 507;

[0079] X-ray focusing device 508;

[0080] X-ray source 509;

[0081] Stage controller 601;

[0082] A first light source 602;

[0083] A second light source 603;

[0084] A first detector 604;

[0085] A third light source 701;

[0086] A second detector 702;

[0087] The third detector 703;

[0088] Terminal device 30;

[0089] Processor 301;

[0090] Memory 302;

[0091] Computer program 303. DETAILED DESCRIPTION

[0092] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0093] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0094] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0095] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0096] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0097] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0098] The embodiment of the present application provides a calibration method for an X-ray fluorescence spectrometry analysis device, wherein the calibration is performed using a calibration wafer; the calibration wafer comprises a B calibration area, the B calibration area comprises at least two B element areas consisting of elements with known X-ray fluorescence spectra, and the boundaries of the B element areas pass through a preset B area test point; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with a reference coordinate, and the detector of the analysis device acquires the X-ray fluorescence spectrum of the element at the light spot; within the light spot area centered on the B area test point, the area ratio of the B element area is a preset test ratio;

[0099] By way of example and not limitation, Figure 4A schematic diagram of the structure of an optional calibration wafer is shown; wherein, four B element areas of a cross-window structure are set in the B calibration area in the lower right part, the elements of each B element area are different, and the elements of any of the B element areas correspond to the light source target material of the analysis device, that is, the X-rays emitted by the light source of the analysis device can excite the elements in any of the B element areas.

[0100] In a preferred embodiment, the excitation spectra of elements in different B element regions do not overlap.

[0101] like Figure 1 As shown, the calibration method includes:

[0102] Step 102, calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the elements in the B element area, and recording the peak position intensity of the B element area as the reference intensity;

[0103] In step 102 , the return signal of the detector includes two parts, namely, peak position and intensity. The peak position part is used to calibrate the detector so that the peak position of the excitation spectrum of a specific element is consistent with its actual peak position, and the intensity part is used for calling in step 104 .

[0104] Step 104 , calibrating the reference coordinates of the light spot according to the detector return signal, the test ratio, and the reference intensity when the reference coordinates of the light spot coincide with the test point of zone B.

[0105] In the various embodiments of the present application, the concepts of "calibration" and "calibration" can be used interchangeably in some cases.

[0106] The purpose of this embodiment is to calibrate the peak position of the analysis device and to finely adjust the coordinates of the light spot using the calibrated peak position information.

[0107] The structure of a typical X-ray fluorescence spectrometer is as follows: Figure 6 shown.

[0108] When the analysis device moves the X-ray light source 509 through the light source carrier (i.e., the mechanical movable table 505 located at the X-ray light source 509), it can feed back the reference coordinates of the light spot generated by the X-ray light source 509 irradiating the measurement area 506. The reference coordinates may have a certain degree of error (such as the accumulated error caused by the movement of the mechanical movable table 505), and thus be inconsistent with the actual coordinates of the light spot. The purpose of executing step 104 is to eliminate this inconsistency.

[0109] However, during the peak position calibration, that is, during the execution of step 102, it is necessary to ensure that the light spot is located in the B element area. Since the light spot at this time has not been finely calibrated in step 104, there are two optional solutions on how to ensure that the light spot is located in the B element area (these two solutions can also be used at the same time).

[0110] The first solution is to set a larger B element area to ensure that even if there is an error between the reference coordinates and the actual coordinates, the magnitude of the error is not higher than the magnitude of the B element area size.

[0111] The second solution is to roughly adjust the reference coordinates before executing step 102 so that the light spot can be roughly located in the B element area when step 102 is executed.

[0112] There are multiple optional implementations of the coarse adjustment step in the second solution. This application provides a better implementation in the subsequent embodiments. Please refer to the subsequent embodiments for details.

[0113] When the first solution and the second solution are executed simultaneously, an optimal empirical size of the B element region is four times the maximum size of the light spot.

[0114] In addition, since the calibration wafer may be asymmetric, the position and angle of the calibration wafer should be calibrated before step 102 is performed. Figure 6 The analytical equipment shown is:

[0115] In the initial state, the calibration wafer 5021 at the first position is moved by the manipulator 503 to the wafer position calibration device 504, so as to perform the above-mentioned position and angle calibration on the calibration wafer 5022 at the second position. Then the manipulator 503 moves the calibration wafer 5022 at the second position to the main body of the analysis equipment, and the mechanical movable table 505 moves the calibration wafer 5023 at the third position to the measurement area 506 (the mechanical movable table 505 located at the calibration wafer is defined as a wafer carrier) to execute the steps of this embodiment.

[0116] Figure 6 Also shown is a schematic diagram of the top-down positional relationship of the X-ray detector 507, the X-ray converging device 508 and the X-ray light source 509. The X-rays emitted by the X-ray light source 509 are converged by the X-ray converging device 508 and incident on the calibration wafer in the measurement area 506 (in the calibration process, they are incident on the calibration wafer, and in the actual test process, they should be incident on the test sample), exciting the electrons of the atoms in the preset element area on the calibration wafer (in the actual test, the electrons of the atoms in the test sample are excited) to generate an X-ray fluorescence spectrum and be received by the X-ray detector 507.

[0117] The execution subject of this embodiment may be a processor built into the analysis device, or an external computer processor, which can receive the coordinate signal of the mechanical movable table 505 and the return signal of the X-ray detector 507 to execute steps 102 and 104.

[0118] It is worth noting that the coordinate signal of the light source carrier can be converted into the reference coordinate of the light spot after processing. This conversion process can be completed by the built-in processor or MCU of the analysis device, or by the processor of an external computer. The optical path parameters required in the conversion process are given by the analysis device.

[0119] In an optional embodiment, if Figure 7 As shown, the analysis device includes two light sources, namely, a first light source 602 and a second light source 603, and a detector, namely, a first detector 604. In this embodiment, since the two light sources are respectively located above and to the sides of the measurement area 506, the light spot formed by the light source irradiating the calibration wafer at the measurement area 506 is an elliptical light spot. Considering that the size of the elliptical light spot may change during the movement of the light source in the height direction (i.e., in the direction perpendicular to the calibration wafer) to complete the focusing, in a preferred solution, the boundary of the B element area can ensure that the area ratio of each B element area in the elliptical light spot of any possible size is the same.

[0120] In addition, the execution principle of step 104 is that the irradiation area of ​​the light spot is proportional to the intensity of the signal returned by the detector. If it is defined that when 100% of the area of ​​the light spot is used to irradiate any B element area in step 102, the signal intensity returned by the detector is 1, then when 25% of the area of ​​the light spot (assuming that the test ratio of the B element area is 25%) is used to irradiate the B element area in step 104, the signal intensity returned by the detector should be 0.25.

[0121] However, in actual tests, the illumination intensity of each point on the light spot is not necessarily equal. It is usually strong in the center and weak at the edge. The analytical equipment used for calibration may not be calibrated for the light intensity distribution. In this case, the principle that the illumination area of ​​the light spot is proportional to the intensity of the detector return signal may not necessarily apply. The detector return signal illuminated by 25% of the area near the center of the light spot and the detector return signal illuminated by 25% of the area near the edge of the new light spot may have a large difference.

[0122] In order to overcome this problem, and considering that the calibration calculation is faster and easier when the test ratios of different B element areas are equal, in a more preferred embodiment, the major axis and / or minor axis of the spot ellipse centered at the test point in area B coincides with the boundary of the B element area to divide the elliptical spot into two or four parts of equal area.

[0123] In another optional embodiment, Figure 8 As shown, the analysis device includes a light source, namely the third light source 701, and two detectors, namely the second detector 702 and the third detector 703. In this embodiment, since the light source is located directly above the measurement area 506, the light spot formed by the light source irradiating the calibration wafer at the measurement area 506 is a circular (perfect circular) light spot. Although the problem of inconsistent intensity of each point in the above light spot may still exist, due to the symmetry of the circular light spot, the boundary setting of the B element area can be more flexible, that is, in a more preferred embodiment, any radius or diameter of the circular light spot centered at the test point of the B area coincides with the boundary of the B element area, so as to divide the circular light spot into any number of parts (or any number of parts with equal areas).

[0124] That is to say, there is a preferred solution based on the present embodiment:

[0125] If the light spot is an elliptical spot, the major axis and / or minor axis of the light spot ellipse centered at the test point in zone B coincides with the boundary of the B element zone; if the light spot is a circular spot, any radius or diameter of the circular spot centered at the test point in zone B coincides with the boundary of the B element zone.

[0126] This preferred scheme provides better B-element zone boundary setting schemes for elliptical light spots and circular light spots respectively. This setting can reduce the difficulty of preparing the B-element zone of the calibration wafer while ensuring the calibration effect, while overcoming the possible problem of inconsistent light intensity at each point of the light spot and no algorithm correction (or poor algorithm correction effect).

[0127] It is worth noting that if the analysis has already corrected and compensated for the spot intensity distribution to ensure that the detectors with the same area illuminated return signal intensity is constant, it is not necessary to adopt the above preferred solution, and the calibration effect can be achieved by only using the solution of this embodiment.

[0128] The beneficial effects of this embodiment are:

[0129] The detector peak position is calibrated for the B element area, and based on the reference intensity, the spot position is accurately calibrated using the area ratio of each B element interval, thus achieving the joint calibration of the optical path, peak position and intensity.

[0130] Ideally, the reference coordinates of the light spot are consistent with the real coordinates. When the reference coordinates of the light spot coincide with the test point in zone B, the ratio of the intensity of the signal returned by the detector to the reference intensity of any of the B element zones should be consistent with the area ratio of the B element zone within the official area centered at the test point in zone B, that is, the test ratio. Therefore, it is only necessary to adjust the position of the light spot to meet the aforementioned ratio consistency condition. It can be considered that the reference coordinates of the light spot should be the real coordinates of the test point in zone B at this time, thereby calibrating the optical path. Considering that the detector accuracy of XRF is quite sensitive, this optical path calibration has better accuracy than the traditional method.

[0131] According to the above embodiment, in this embodiment:

[0132] The calibration wafer further includes a C calibration area, wherein the C calibration area includes a C element area composed of elements with known X-ray fluorescence spectra; at least one of the C element areas has an area that satisfies a preset area equivalence condition with the area of ​​the light spot;

[0133] In an optional embodiment, the area equivalence condition means that the difference between the area of ​​the C element region and the area of ​​the light spot is less than a set threshold, or the area ratio of the C element region to the light spot satisfies a preset range.

[0134] In order to ensure that the light spots of different sizes generated after adjusting the light source in the height direction for focusing can all meet the condition that "the area of ​​at least one C element region satisfies the preset area equivalent condition with the area of ​​the light spot", Figure 4 The upper right shows a feasible C calibration area setting scheme. Figure 4 In the figure, the element areas in the dotted box have the same elements, and there are 3 groups of C element area groups composed of different elements in the upper right C calibration area, and each C element area group includes multiple C element areas of different sizes. In this way, it is only necessary to adjust the size of each C element area in the C element area group to cover all possible spot sizes to meet the condition that "there is at least one C element area whose area satisfies the preset area equivalence condition with the area of ​​the spot".

[0135] After the step of calibrating the reference coordinates of the light spot according to the detector return signal, the test ratio and the reference intensity when the reference coordinates of the light spot coincide with the test point of zone B, the step further includes:

[0136] Determine the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establish or adjust the light intensity distribution function according to the light intensity distribution of the light spot;

[0137] The light intensity distribution function is used to correct the intensity of the signal returned by the detector to a value that is positively correlated with the irradiation area of ​​the light spot.

[0138] In an optional embodiment, the signal strength I(Xs, Ys) received by the detector when the center coordinates of the light spot are (Xs, Ys) can be expressed by the following equation:

[0139] I(Xs,Ys)=C*∫Area(i,j)*Spot(i,j)didj

[0140] Wherein, C is a constant that reflects the ratio of the primary / secondary X-ray fluorescence intensity of different materials. Area(i, j) represents the overlapping area of ​​the spot and the circular sample being measured. Spot(i, j) reflects the intensity distribution of the overlapping area spot; i and j are parameters used to reflect the overlapping position of the spot and the C element area.

[0141] Through dot matrix scanning, the system can calculate the distribution of Spot (i, j) at different positions, thereby calibrating the detector signal strength.

[0142] The beneficial effects of this embodiment are:

[0143] The detector return signal that partially overlaps with the C element area is used to build a model to obtain the light intensity distribution within the light spot. The detector return signal is corrected based on the light intensity distribution within the light spot so that when the light spot irradiation area is the same, the intensity of the return signal in each area is consistent, which provides convenience for the testing of small-size samples.

[0144] According to any of the above embodiments, in this embodiment:

[0145] The step of recording the peak intensity of the B element region as the reference intensity comprises:

[0146] Move the light source in a direction perpendicular to the calibration wafer, and record the coordinate of the light source when the intensity of the return signal of the detector is greater than a first preset intensity, which is recorded as a Z coordinate;

[0147] If it is determined that the Z coordinates of different B element areas are the same, the return signal intensity of the detector when the light source is at the Z coordinate and the light spot is located in the B element area is recorded as the reference intensity of the B element area; otherwise, the optical path of the analysis device is calibrated by a preset method.

[0148] It is worth noting that the above-mentioned “same” should refer to the same within the allowable error range, rather than absolute same in the strict sense. The allowable error range can be a parameter preset based on experience.

[0149] In this embodiment, if the Z coordinates of each B element area are consistent (ie, the height is consistent), it means that this height is the focus position, and the system automatically records and saves it. If they are inconsistent, it means that the system optical path is abnormal, and manual intervention is required to calibrate the optical path focusing device.

[0150] The beneficial effects of this embodiment are:

[0151] The system optical path is verified by the Z coordinate. When the optical path is focused normally, the Z coordinate of the focus position for the B element area of ​​different elements should be the same. Therefore, verifying the optical path by the Z coordinate can reliably eliminate the optical path problem and provide a good equipment foundation for the calibration of other parameters.

[0152] According to any of the above embodiments, in this embodiment:

[0153] The calibration wafer further includes a D calibration region, wherein the D calibration region includes at least two D element regions of different thicknesses composed of elements with known X-ray fluorescence spectra;

[0154] It is worth noting that the size of the D element zone is related to whether the calibration step of the C calibration zone (or other calibrations on the spot intensity distribution) has been performed. If the spot intensity has been calibrated before the steps of this embodiment, or the analysis instrument itself has a spot intensity distribution function, then when the steps of this embodiment are executed, there is no need to make additional restrictions on the size of the D element zone. Otherwise, it should be ensured that the size of the D element zone is larger than the spot size so that the spot can fall completely into any D element zone.

[0155] After the step of determining the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establishing or adjusting the light intensity distribution function according to the light intensity distribution of the light spot, the method further includes:

[0156] Establishing or adjusting a film thickness regression function according to the return signal intensity of the detector when the light spot is in the D element region and the thickness of the D element region;

[0157] The film thickness regression function is a function of the sample film thickness at the light spot and the intensity of the signal returned by the detector.

[0158] In an optional embodiment, a linear regression model is used as the fitting basis of the film thickness regression function, and the regression model can be:

[0159] T i =K i *M i *I i

[0160] Where T i Represents the film thickness of the sample being tested, Ki Represents a system constant, reflecting the signal sensitivity of the system to different samples. i It is a calibration matrix term that reflects the absorption and enhancement effect of all X-ray radiation received by the sample under test. Ii represents the net intensity of the characteristic energy peak after removing the influence of background noise and other energy peak overlap effects.

[0161] The beneficial effects of this embodiment are:

[0162] By establishing or adjusting the film thickness regression function through the return signals of the detectors in the D element zone with different thicknesses, the thickness information of the sample can be given more accurately in actual testing, which is beneficial to improving the accuracy and reliability of the test results, especially the test results in the semiconductor field.

[0163] According to any of the above embodiments, in this embodiment:

[0164] The calibration wafer further includes an A calibration area, wherein the A calibration area includes an A element area composed of elements with known X-ray fluorescence spectra; the A element area includes two rectangular element areas orthogonal to each other in the long axis direction, and the width of the rectangular element area is of the same order of magnitude as the size of the light spot;

[0165] Before the step of calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the elements in the B element area, and recording the peak position intensity of the B element area as the reference intensity, the step further includes:

[0166] Move the light spot whose reference coordinate is located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the intensity of the return signal of the detector is greater than the second preset intensity;

[0167] The reference coordinates of the light spot are corrected according to the first coordinates and the second coordinates.

[0168] In an optional embodiment, after the step of correcting the reference coordinates of the light spot according to the first coordinates and the second coordinates, the method further includes:

[0169] Return to the step of moving the light spot with the reference coordinate located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the return signal intensity of the detector is greater than the second preset intensity, until the values ​​of the first coordinate and the second coordinate are less than the width of the rectangular element area.

[0170] The beneficial effects of this implementation are:

[0171] By repeatedly iteratively correcting the spot reference coordinates, the contradiction between the width of the rectangular element area, that is, the difficulty of correction and the accuracy of correction is weighed. A rectangular element area width of the same order of magnitude as the spot size is used. Although it is easier to find a stronger return signal from the detector, the adjustment accuracy of the reference coordinates is limited by the width of the rectangular element area and may not be accurate enough. Therefore, this problem can be overcome through the iterative correction method, thereby ensuring the effectiveness of the coarse adjustment of the spot reference coordinates.

[0172] The beneficial effects of this embodiment are:

[0173] By setting an orthogonal rectangular element area, the detector returns a stronger signal when the light spot is located in the rectangular element area. Therefore, even if the reference coordinates of the light spot are greatly different from the actual coordinates, the first coordinates and the second coordinates for correcting the reference coordinates can still be accurately given by translating the light spot, thereby achieving the effect of coarse adjustment of the reference coordinates of the light spot.

[0174] In combination with the above embodiments, an exemplary complete embodiment for calibration of the analysis device that has not been calibrated is given below.

[0175] This embodiment is implemented on the basis of a calibration wafer with multiple patterns and multiple elements, and can efficiently and automatically realize the daily maintenance and performance calibration of the machine.

[0176] This embodiment is applicable to the fields of biology, medicine, semiconductor, chemical analysis, etc. that use X-ray fluorescence spectroscopy analysis technology for measurement. Specific applications include: X-ray fluorescence analysis, X-ray diffraction analysis, X-ray reflection analysis, X-ray scattering optical path calibration and detector calibration.

[0177] Some optional independent calibration methods are introduced below.

[0178] Optical path calibration part:

[0179] (1) By designing the optical path, the laser optical path is ensured to be confocal with the X-ray, and the laser spot is used to determine the position of the X-ray spot.

[0180] (2) Use X-rays to irradiate photosensitive materials and use the visible light fluorescence they emit to determine the location and size of the light spot.

[0181] (3) The detector is used to read the distribution of the secondary X-ray signal emitted by the sample, combined with the specific pattern of a certain characteristic element on the sample surface or the combined pattern of different characteristic elements, to calculate the spot size and area distribution.

[0182] System (parameter) calibration part:

[0183] (1) Calibration of the detector's sensing energy peak position. Using the secondary X-ray energy peak position of characteristic elements (such as Cu or Mn), the energy peak position of the sensor at different peaking times is calibrated to ensure the consistency of the energy peak position at different resolutions.

[0184] (2) Calibration of the correlation between sample thickness and sensor signal intensity. Using different elements and different thicknesses, the system parameters (sampling background noise, X-ray absorption and enhancement effect of sample elements, characteristic peak energy spectrum overlap, etc.) are calibrated.

[0185] These independent calibration / calibration methods have some problems, specifically:

[0186] Optical path calibration:

[0187] (1) Manual debugging and calibration are required in the early stage, and the system cannot be calibrated in real time. Later maintenance requires human intervention, which is often time-consuming and repeatability cannot be guaranteed. Moreover, if the laser energy is too high, it may damage the sample.

[0188] (2) This positioning is relatively rough and lacks accuracy through visual inspection. Moreover, due to the size of the fluorescent photosensitive unit, the visible light spot area may be larger than the actual X-ray spot area, affecting the precise positioning of the spot.

[0189] (3) The intensity distribution of the light spot itself and the size of the sample detection area have a high computational requirement. In addition, the light spot position needs to be roughly known in order to place the light spot in a specific graphic area for measurement. Since the light spot of semiconductor measurement equipment is small (a diameter of tens of microns), initial positioning is difficult.

[0190] System calibration:

[0191] The system calibration process often requires manual replacement of multiple samples for calibration, which is time-consuming and has poor reliability. It is easy to introduce manual operation errors and it is impossible to obtain real-time machine data.

[0192] In addition, these solutions that separate optical path calibration from system calibration have the problem of low efficiency and are unable to detect the machine status in real time to achieve automated calibration.

[0193] In order to solve these problems, this embodiment designs different partitions of the wafer, and unifies the optical path calibration (spot positioning, spot light intensity distribution) and system calibration (detection peak calibration, sample film thickness and signal intensity correlation calibration) on a standard-sized wafer. By using the semiconductor XRF measurement machine to calibrate the wafer up and down, on the one hand, the optical path calibration and system calibration are unified. On the other hand, the machine is loaded, monitored, calibrated, and then unloaded without manual intervention, realizing automatic and precise calibration. Moreover, by testing the calibration wafer together with the wafer sample to be measured, the real-time status of the machine during the measurement process can also be monitored.

[0194] Figure 4 The calibration wafer of this embodiment is shown, including four sectors A, B, C, and D, which respectively correspond to coarse adjustment of the spot position, detector peak position calibration, spot focus and spot position fine adjustment, spot intensity distribution calibration, and system algorithm regression coefficient calibration.

[0195] In area A (i.e., A calibration area), two strips of the same characteristic element material (the element is determined by the commonly used light source target material) form a cross (such as Fig. 9 ). It is deposited on silicon wafers by PVD or CVD. The strip size is determined by the wafer size and the size of the measured spot. (Take a 12-inch wafer as an example, the spot diameter is 1mm, the strip square size is 100mm long, 1mm wide, and 0.1mm high)

[0196] Specifically, the length of the strip (rectangular element area) matches the size of the calibration wafer. For this embodiment, it matches the size of the A calibration area. The width of the strip (rectangular element area) is at the same order of magnitude as the spot size. For the elliptical spot mentioned in the above embodiment, its short axis length can be at the same order of magnitude to obtain a better coarse adjustment effect.

[0197] In area B (i.e., area B calibration), a window pattern (such as Fig.10 ). The square area must be guaranteed to be more than 4 times the measured spot area. The spot area here refers to the maximum spot area that can be obtained by adjusting the light source in the height direction. (Take a 12-inch wafer as an example, the side length of each square area of ​​the window pattern is 40mm and the height is 0.1mm) Determine the type of element based on the measured light source target. Ensure that under the same light source, the four elements can all excite secondary X-ray fluorescence, and the energy peaks of the corresponding fluorescence of the four elements should not overlap. The window-shaped area elements are deposited on the silicon wafer by PVD or CVD.

[0198] In the C area (i.e., the C calibration area), there are circular patterns of different sizes (such as Fig.11), the element areas in different dotted boxes use different elements. A circular pattern of a specific size is selected according to the light source target element and the spot size. It is deposited on a silicon wafer by PVD or CVD.

[0199] In the D area (i.e., the D calibration area), there are square patterns of the same size (taking a 12-inch wafer as an example, the side length of the square area is 10 mm) and different thicknesses (such as Fig.13 ). It is deposited on silicon wafers by PVD or CVD. The element areas in different dotted boxes use different elements. Specific elements can be selected for system calibration according to the light source target material.

[0200] Semiconductor XRF measurement equipment, usually includes Figure 6 Several parts are shown in it. First, the robot 503 takes out the calibration wafer in the wafer transfer box (i.e., the calibration wafer 5021 in the first position), and places it on the wafer position pre-calibration device (i.e., the calibration wafer 5022 in the second position); after pre-calibration, it is placed in the mechanical stage of the measuring machine (i.e., the mechanical movable stage 505); the stage receives the position signal and moves the wafer to a specific wafer measurement position. The X-rays are focused on the sample surface through the converging light path to form an elliptical focal spot. The sample in the focal spot area is excited to produce secondary fluorescence. The sensor directly above receives the fluorescence signal, which is processed by the system and converted into film thickness information and elemental composition information. As an implementation method, refer to Figure 7 , the calibration wafer is moved by the machine to the position directly below the detector, and light source 1 (first light source 602) and light source 2 (second light source 603) emit X-rays to excite different areas of the wafer. By analyzing the fluorescence signal, the machine can automatically calibrate the optical path and system parameters. For the specific process, refer to Figure 5 .

[0201] It is worth noting that, for an analysis device having two light sources, the steps of this embodiment or any of the above embodiments should be performed for the first light source 602 and the second light source 603 respectively, so as to complete calibration of the two light sources respectively.

[0202] In particular, since the calibration wafer has four partitions A, B, C, and D, in an optional embodiment, the first light source 602 and the second light source 603 can perform calibration in different partitions of the calibration wafer at the same time. It can be understood that since the calibration steps of the four partitions A, B, C, and D in the complete solution are executed sequentially, the light spot of the first light source 602 is first calibrated in partition A, and then transferred to partition B for calibration after completion. At this time, the light spot of the second light source 603 is transferred to partition A for calibration.

[0203] Reference Figure 5 , the calibration is performed as follows:

[0204] First, the device moves the stage to move the cross center in the lower left sector (A) of the calibration wafer to the initial spot center position (X0, Y0) considered by the system, as shown in Fig. 9 . Taking this position as the initial point, the stage moves the wafer along the X-axis direction, and the detector continuously collects the signal strength of the characteristic elements at different positions. Record the coordinates of the point with the strongest signal (X1, Y0). Then the stage returns to the initial point and starts to move the wafer along the Y-axis direction, and synchronously collects signals. Record the coordinates of the point with the strongest signal (X0, Y1). The system automatically calculates the deviation value between (X0, Y0) and (X1, Y1), and compensates for the deviation by moving the light source stage. After compensation, move the cross center back to the spot center position recognized by the system, and repeat the above steps until the deviation value is less than the strip width d, which means that the coarse adjustment of the spot center position calibration is completed.

[0205] It is worth noting that the above coordinate system is a Cartesian coordinate system established with the plane where the calibration wafer is located as the XY plane and the upward direction perpendicular to the calibration wafer as the positive direction of the Z axis.

[0206] Then, the system moves the stage to place the light spot at the center of the window pattern i in the lower right sector B of the calibration wafer, referring to Fig.10 . The system calibrates the peak position of the detector based on the element in the i pane. After calibration, move the stage and place the light spot in the ii pane. The system verifies the peak position of the element in the ii pane. If there is an offset, continue to calibrate. Then move to the iii area to verify and calibrate b3. Then verify and calibrate the iv area. Repeat this cycle twice to ensure that the energy peaks of the four elements are accurately calibrated. Then, scan along the Z direction in the four pane areas respectively to find the Z position of the strongest signal. If the Z heights of the four areas are consistent, it means that this height is the focus position, and the system automatically records and saves it. If they are inconsistent, it means that there is an abnormality in the system optical path, and manual intervention is required to calibrate the optical path focus device. After determining the focus Z height, the system automatically moves the junction of the four panes to the center position of the light spot (Xc, Yc). Fig.10 , at this time the light spot spans four areas, and the energy spectrum should simultaneously display the characteristic energy peaks of the four elements. Since the irradiation area of ​​each area is reduced to 1 / 4 of the original area at this time, the energy characteristic peak intensity of the elements in each area should also be reduced to 1 / 4. If the energy intensity is incorrect, the stage moves within a small range and collects signals at the same time until it moves to the (Xi, Yi) position and the intensity of each characteristic peak meets the requirements. The controller automatically calculates the deviation between (Xc, Yc) and (Xi, Yi) and fine-tunes the light source stage to compensate for the deviation. Then, the sample stage moves back to the (Xc, Yc) position to collect signals to ensure that the energy characteristic peak intensity of the elements in the four areas is reduced to 1 / 4 of the original signal. If not, repeat the above process until the signal intensity requirement is met. This completes the fine-tuning of the center position of the light spot.

[0207] Next, according to the size of the adjusted light spot and the elements of the light source target, the system automatically searches for a suitable circular area in the upper right sector C of the calibration wafer, such as Fig.11 , calibrate the spot signal intensity distribution. Taking the Cu target X-ray light source, the sample surface elliptical focal spot short diameter size is 100um as an example, the system automatically selects a 100um circular Ti element pattern. Dot scanning is performed around the circle, such as Fig.12 As the dot scanning proceeds, different areas of the light spot will overlap with the circular sample. Since the light spot itself is distributed with different light intensities, at this time, the signal I collected by the detector ij It will change with the size of the sample area of ​​the overlapping part and the light intensity of the overlapping part of the spot. The light intensity I(Xs, Ys) received by the detector at the wafer (Xs, Ys) can be expressed by the following equation:

[0208] I(Xs,Ys)=C*∫Area(i,j)*Spot(i,j)didj

[0209] Where C is a constant that reflects the ratio of the primary / secondary X-ray fluorescence intensity of different materials. Area(i, j) represents the overlapping area between the spot and the circular sample being measured. Spot(i, j) reflects the intensity distribution of the overlapping area spot.

[0210] Through dot matrix scanning, the system can calculate the distribution of Spot (i, j) at different positions, thereby calibrating the detector signal strength.

[0211] Finally, the system automatically finds the appropriate square pattern group (such as Fig.13 ), scan square films of different thicknesses in the same group respectively, and calibrate the film thickness algorithm regression model through the different signal intensities obtained. In the field of semiconductor measurement, the thickness and component measurement accuracy of the film layer is required to be high, and the accuracy must be less than 1%. In order to meet the requirements, XRF measurement equipment needs to sample a suitable regression model for data analysis. The general regression model is described as follows,

[0212] T i =K i *M i *I i

[0213] Where T i Represents the film thickness of the sample being tested, K i Represents a system constant, reflecting the signal sensitivity of the system to different samples. i is a calibration matrix term that reflects the absorption and enhancement effects of all X-ray radiation received by the sample under test. iRepresents the net intensity of the characteristic energy peak after removing the influence of background noise and other energy peak overlap effects.

[0214] This embodiment uses a simple linear regression model to demonstrate the role of the calibration wafer of the present invention. Fig.13 Four Ti films of different thicknesses in sector D of the wafer are shown. Different peaks represent different film thicknesses. In a simple linear regression model, the signal intensity I and the film thickness T of the sample under test can be described by the following equation,

[0215] T i =C0+C1*I i

[0216] Among them, there are two regression coefficients, C0 and C1. The system can use the four signal peaks to fit the regression coefficients of the linear regression model: C0 = -906.4C1 = 79.606, as shown in Fig.14 Usually two sets of data can fit C0 and C1, and four sets of data can improve the accuracy and reliability of the fitting.

[0217] In summary, this embodiment uses the different designs of the four sectors of the calibration wafer to achieve the calibration of the center position of the light spot, the focus height of the light spot, the intensity distribution of the light spot, the energy peak position of the system, and the coefficient of the film thickness regression model of the system. The whole process is fully automated, efficient and accurate.

[0218] Compared with the prior art, this embodiment:

[0219] The whole process is controlled by computer automatically and no manual operation is required.

[0220] Multiple calibrations are combined in an orderly manner and implemented in a unified manner to improve efficiency.

[0221] Sample testing and machine monitoring can be performed simultaneously, providing real-time feedback on machine measurement accuracy and enabling timely adjustments.

[0222] The technical effect of this embodiment is:

[0223] The optical path calibration is realized, including the effective unification of spot focus, spot center calibration, and spot intensity distribution calibration, and the energy peak accuracy of the system and the regression parameters of the film thickness algorithm are calibrated to improve the accuracy of the machine.

[0224] Further, as another embodiment, the structure of the calibrated measuring optical path is changed, referring to Figure 8; The X-rays are focused vertically on the sample surface through the converging optical path to form a circular focal spot. The sample in the focal spot area is excited to produce secondary fluorescence. The sensors located on the left and right measurement receive the fluorescence signals, which are processed by the system and converted into film thickness information and elemental composition information. The optical path calibration method of this structure is basically the same as that of the previous embodiment. The spot position is coarsely adjusted through sector A, the detector energy peak is calibrated through sector B, the spot position is finely adjusted, and the Z position corresponding to the X-ray focus is found. Sector C calculates the spot intensity distribution. However, the spot changes from an ellipse to a circle. When calculating the spot intensity distribution, the calculation of the overlapping area needs to be changed. In addition, the film thickness regression model calibrated by the system will also change with the difference between the X-ray incident angle and the detector receiving angle, and different algorithms are required to calculate the regression coefficient.

[0225] In summary, the key points of each embodiment of the present application are:

[0226] 1. A wafer design for automated calibration of XRF semiconductor measurement equipment.

[0227] 2. A calibration scheme for simultaneously achieving optical path calibration and system calibration.

[0228] 3. A calibration scheme for X-ray spot position, size, and intensity distribution.

[0229] The following sub-programmes are included:

[0230] 1. Wafer design layout.

[0231] 2. Optical path calibration scheme.

[0232] 3. System calibration plan.

[0233] 4. Unified calibration scheme for optical path and system calibration.

[0234] In addition, the various embodiments of the present application are intended as examples rather than limitations. In actual applications, the types of deposited elements in each sector of the wafer can be changed according to the actual light source target material, the element area image size in each sector of the wafer can be changed according to the actual spot size, and the layout of each sector of the wafer can be changed according to actual needs.

[0235] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0236] Corresponding to the calibration method of the X-ray fluorescence spectrometer described in the above embodiment, Figure 2 A structural block diagram of a calibration device for a semiconductor X-ray fluorescence spectrometer analysis device provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0237] Reference Figure 2 , the device:

[0238] Calibration is achieved using a calibration wafer; the calibration wafer includes a B calibration area, the B calibration area includes at least two B element areas composed of elements with known X-ray fluorescence spectra, and the boundary of the B element area passes through a preset B area test point; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with a reference coordinate, and the detector of the analysis device obtains the X-ray fluorescence spectrum of the element at the light spot; within the light spot area centered on the B area test point, the area ratio of the B element area is a preset test ratio;

[0239] The calibration device comprises:

[0240] A B-zone peak position module 201 is used to calibrate the peak position of the detector according to the return signal of the detector when the light spot is located in the B-zone and the X-ray fluorescence spectrum of the elements in the B-zone, and record the peak position intensity of the B-zone as the reference intensity;

[0241] The B-zone coordinate module 202 is used to calibrate the reference coordinate of the light spot according to the detector return signal, the test ratio and the reference intensity when the reference coordinate of the light spot coincides with the test point of the B-zone.

[0242] If the light spot is an elliptical spot, the major axis and / or minor axis of the light spot ellipse centered at the test point in zone B coincides with the boundary of the B element zone; if the light spot is a circular spot, any radius or diameter of the circular spot centered at the test point in zone B coincides with the boundary of the B element zone.

[0243] Specifically, the B zone peak position module 201 includes:

[0244] Benchmark strength unit for:

[0245] Move the light source in a direction perpendicular to the calibration wafer, and record the coordinate of the light source when the intensity of the return signal of the detector is greater than a first preset intensity, which is recorded as a Z coordinate;

[0246] If it is determined that the Z coordinates of different B element areas are the same, the return signal intensity of the detector when the light source is at the Z coordinate and the light spot is located in the B element area is recorded as the reference intensity of the B element area; otherwise, the optical path of the analysis device is calibrated by a preset method.

[0247] Further, the calibration wafer further includes a C calibration area, the C calibration area includes a C element area composed of elements with known X-ray fluorescence spectra; the area of ​​at least one of the C element areas satisfies a preset area equivalence condition with the area of ​​the light spot; the calibration wafer further includes a D calibration area, the D calibration area includes at least two D element areas with different thicknesses composed of elements with known X-ray fluorescence spectra; the calibration wafer further includes an A calibration area, the A calibration area includes an A element area composed of elements with known X-ray fluorescence spectra; the A element area includes two rectangular element areas orthogonal in the long axis direction, and the width of the rectangular element area is of the same order of magnitude as the size of the light spot;

[0248] The calibration device also includes:

[0249] A C-zone calibration module, used to determine the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C-element zone, and to establish or adjust the light intensity distribution function according to the light intensity distribution of the light spot;

[0250] The light intensity distribution function is used to correct the intensity of the signal returned by the detector to a value that is positively correlated with the irradiation area of ​​the light spot.

[0251] A D-zone calibration module, used to establish or adjust a film thickness regression function according to the return signal intensity of the detector when the light spot is in the D-element zone and the thickness of the D-element zone;

[0252] The film thickness regression function is a function of the sample film thickness at the light spot and the intensity of the signal returned by the detector.

[0253] Area A calibration module, used for:

[0254] Move the light spot whose reference coordinate is located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the intensity of the return signal of the detector is greater than the second preset intensity;

[0255] The reference coordinates of the light spot are corrected according to the first coordinates and the second coordinates.

[0256] Return to the step of moving the light spot with the reference coordinate located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the return signal intensity of the detector is greater than the second preset intensity, until the values ​​of the first coordinate and the second coordinate are less than the width of the rectangular element area.

[0257] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0258] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0259] The present application also provides a terminal device, such as Figure 3 As shown, the terminal device 30 includes: at least one processor 301, a memory 302, and a computer program 303 stored in the memory and executable on the at least one processor, and the processor implements the steps in any of the above-mentioned method embodiments when executing the computer program.

[0260] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0261] An embodiment of the present application provides a computer program product. When the computer program product runs on a mobile terminal, the mobile terminal can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0262] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium can at least include: any entity or device that can carry the computer program code to the camera / terminal device, recording medium, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), electric carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0263] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0264] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0265] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0266] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0267] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A calibration method for an X-ray fluorescence spectrometer, characterized in that: Calibration is achieved using a calibration wafer; the calibration wafer includes a B calibration area, the B calibration area includes at least two B element areas composed of elements with known X-ray fluorescence spectra, and the boundaries of the B element areas pass through preset B area test points; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with reference coordinates, and the detector of the analysis device obtains the X-ray fluorescence spectrum of the element at the light spot; In the spot area centered at the test point in area B, the area ratio of the element area B is a preset test ratio; The calibration method comprises: Calibrate the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the element in the B element area, move the light source in a direction perpendicular to the calibration wafer, and record the coordinates of the light source when the intensity of the return signal of the detector is greater than a first preset intensity, recorded as a Z coordinate; If it is determined that the Z coordinates of different B element regions are the same, the return signal intensity of the detector when the light source is at the Z coordinate and the light spot is located in the B element region is recorded as the reference intensity of the B element region; otherwise, the optical path of the analysis device is calibrated by a preset method; The reference coordinates of the light spot are calibrated according to whether the ratio of the intensity of the signal returned by the detector to the reference intensity when the reference coordinates of the light spot coincide with the test point in zone B is consistent with the test ratio.

2. The calibration method of X-ray fluorescence spectrometry equipment according to claim 1, characterized in that: The calibration wafer further includes a C calibration area, wherein the C calibration area includes a C element area composed of elements with known X-ray fluorescence spectra; at least one of the C element areas has an area that satisfies a preset area equivalence condition with the area of ​​the light spot; After the step of calibrating the reference coordinates of the light spot according to the detector return signal, the test ratio and the reference intensity when the reference coordinates of the light spot coincide with the test point of zone B, the step further includes: Determine the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establish or adjust the light intensity distribution function according to the light intensity distribution of the light spot; The light intensity distribution function is used to correct the intensity of the signal returned by the detector to a value that is positively correlated with the irradiation area of ​​the light spot.

3. The calibration method of X-ray fluorescence spectrometry equipment according to claim 2, characterized in that: The calibration wafer further includes a D calibration region, wherein the D calibration region includes at least two D element regions of different thicknesses composed of elements with known X-ray fluorescence spectra; After the step of determining the light intensity distribution of the light spot according to the intensity of the signal returned by the detector when the light spot partially overlaps with the C element area, and establishing or adjusting the light intensity distribution function according to the light intensity distribution of the light spot, the method further includes: Establishing or adjusting a film thickness regression function according to the return signal intensity of the detector when the light spot is in the D element region and the thickness of the D element region; The film thickness regression function is a function of the sample film thickness at the light spot and the intensity of the signal returned by the detector.

4. The calibration method of an X-ray fluorescence spectrometer according to any one of claims 1 to 3, characterized in that: The calibration wafer further includes an A calibration area, wherein the A calibration area includes an A element area composed of elements with known X-ray fluorescence spectra; the A element area includes two rectangular element areas orthogonal to each other in the long axis direction, and the width of the rectangular element area is of the same order of magnitude as the size of the light spot; Before the step of calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B element area and the X-ray fluorescence spectrum of the elements in the B element area, and recording the peak position intensity of the B element area as the reference intensity, the step further includes: Move the light spot whose reference coordinate is located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the intensity of the return signal of the detector is greater than the second preset intensity; The reference coordinates of the light spot are corrected according to the first coordinates and the second coordinates.

5. The calibration method of X-ray fluorescence spectrometry equipment according to claim 4, characterized in that: After the step of correcting the reference coordinates of the light spot according to the first coordinates and the second coordinates, the method further includes: Return to the step of moving the light spot with the reference coordinate located at the intersection of the long axes of the two rectangular element areas respectively along the long axis directions of the two rectangular element areas to obtain the first coordinate and the second coordinate when the return signal intensity of the detector is greater than the second preset intensity, until the values ​​of the first coordinate and the second coordinate are less than the width of the rectangular element area.

6. The calibration method of X-ray fluorescence spectrometry equipment according to claim 1, characterized in that: If the light spot is an elliptical spot, the major axis and / or minor axis of the light spot ellipse centered at the test point in zone B coincides with the boundary of the B element zone; if the light spot is a circular spot, any radius or diameter of the circular spot centered at the test point in zone B coincides with the boundary of the B element zone.

7. A calibration device for semiconductor X-ray fluorescence spectrometry equipment, characterized in that: Calibration is achieved using a calibration wafer; the calibration wafer includes a B calibration area, the B calibration area includes at least two B element areas composed of elements with known X-ray fluorescence spectra, and the boundaries of the B element areas pass through preset B area test points; the light source of the analysis device can irradiate the calibration wafer to generate a light spot with reference coordinates, and the detector of the analysis device obtains the X-ray fluorescence spectrum of the element at the light spot; In the spot area centered at the test point in area B, the area ratio of the element area B is a preset test ratio; The calibration device comprises: A B-zone peak position module, used for calibrating the peak position of the detector according to the return signal of the detector when the light spot is located in the B-element zone and the X-ray fluorescence spectrum of the element in the B-element zone, moving the light source in a direction perpendicular to the calibration wafer, recording the coordinates of the light source when the return signal intensity of the detector is greater than a first preset intensity, and recording it as a Z coordinate; if it is determined that the Z coordinates of different B-element zones are the same, then the return signal intensity of the detector when the light source is at the Z coordinate and the light spot is located in the B-element zone is recorded as the reference intensity of the B-element zone; otherwise, calibrating the optical path of the analysis device by a preset method; The B zone coordinate module is used to calibrate the reference coordinate of the light spot according to whether the ratio of the intensity of the signal returned by the detector to the reference intensity when the reference coordinate of the light spot coincides with the test point of zone B is consistent with the test ratio.

8. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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