A detector calibration and alignment method for X-ray wafer measurement

Abstract

The present application provides a detector calibration and alignment method for X-ray wafer measurement, including stimulating a fluorescent spot in the visible light band, collecting the spot to mark the spot center identification mark, making the sample center identification mark coincide with the spot center identification mark, and recording the first absolute coordinate (x1, y1) of the stage; moving the stage along the grid at a set speed, monitoring the peak reading of the detector, and recording the second absolute coordinate (x2, y2) of the stage when the peak reading appears; calculating the maximum error coordinate value (Δx, Δy) between the center of the spot image and the center of the fluorescent detector, and determining the number of turns that the fluorescent detector needs to be adjusted according to the error; wherein, (Δx, Δy) = (x2, y2)-(x1, y1); repeating the movement until the maximum error coordinate value (Δx, Δy) = (0, 0).

Description

Technical Field

[0001] The present application belongs to the field of semiconductor chip technology, and more specifically, to a detector calibration and alignment method for X-ray wafer measurement. Background Art

[0002] In the prior art, the detector calibration and alignment workbench used for X-ray wafer measurement, wherein the X-ray fluorescence detector and the camera lens used for positioning are installed in a separate manner. During calibration, the sample is directly scanned by X-rays to stimulate non-visible fluorescence, and the detector is calibrated by the non-visible fluorescence, specifically by using the maximum scanning light intensity method to achieve calibration. However, since the detector and the camera lens are installed in a separate manner, even if the maximum scanning light intensity method is used, it cannot be guaranteed that the center of the X-ray spot coincides with the center of the ROI (Region of Interest) of the structure to be measured on the sample, and the center of the target surface of the detector, thereby causing the problem of low calibration accuracy. For the measurement of small-sized spots, patterned wafers and optical critical dimensions, it is even more difficult to ensure the calibration accuracy of the existing workbench, and it can only meet the requirements of offline measurement and non-patterned wafer measurement, and it is difficult to meet the online measurement requirements of semiconductor process technology. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a detector calibration and alignment method for X-ray wafer measurement to solve the technical problem that the existing detector calibration and alignment method for X-ray wafer measurement cannot meet the requirements of online and pattern wafer measurement.

[0004] To achieve the above purpose, the technical solution adopted in this application is:

[0005] A detector calibration and alignment method for X-ray wafer measurement is provided, the method comprising:

[0006] Using X-rays to excite a fluorescent spot in the visible light band on a fluorescent sample, collecting a spot image corresponding to the fluorescent spot and marking a spot center identification mark at the center of the spot image; wherein the fluorescent sample is placed on a loading surface of a movable loading stage, and the center of the fluorescent sample is marked with a sample center identification mark;

[0007] Move the movable stage to make the sample center identification mark and the light spot center identification mark coincide with each other, and record the first absolute coordinate (x1, y1) of the movable stage when they coincide with each other;

[0008] Switch the fluorescence detector to above the loading surface, and make its detection window opposite and parallel to the loading surface, move the movable stage along an XY coordinate grid of a set size at a set speed, and synchronously monitor the peak reading of the fluorescence detector, and record the second absolute coordinate (x2, y2) of the movable stage when the peak reading appears;

[0009] Calculate the maximum error coordinate value (Δx, Δy) between the center of the spot image and the center of the fluorescence detector, determine the number of turns that the fluorescence detector needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy), and adjust the fluorescence detector according to the number of turns that need to be adjusted; wherein (Δx, Δy) = (x2, y2) - (x1, y1);

[0010] Repeat the process of moving the movable stage along the XY coordinate grid of a set size at a set speed, and repeatedly calculate the maximum error coordinate value (Δx, Δy) between the center of the spot image and the center of the fluorescence detector until the maximum error coordinate value (Δx, Δy) = (0, 0).

[0011] In one embodiment, before the method of using X-rays to excite a fluorescent spot in the visible light band on the fluorescent sample, the method further includes:

[0012] Switching the low-magnification lens to above the object-carrying surface, and adjusting the relative position relationship between the low-magnification lens and the movable stage so that the lens plane of the low-magnification lens and the object-carrying surface are opposite and parallel;

[0013] The movable stage is moved to move the fluorescent sample placed on the stage surface into the field of view of the low-magnification lens.

[0014] In one embodiment, the step of collecting a spot image corresponding to the fluorescent spot and marking a spot center identification mark at the center of the spot image includes:

[0015] An industrial camera is used in conjunction with a low-magnification lens to collect a spot image corresponding to the fluorescent spot in real time, a template matching algorithm is used to identify the spot image, and a spot center identification mark is marked at the center of the spot image.

[0016] In one embodiment, after the movable stage is moved, the sample center identification mark and the light spot center identification mark are made to coincide with each other, and the first absolute coordinate (x1, y1) of the movable stage is recorded when they coincide with each other, and before the fluorescence detector is adjusted so that its detection window and the object surface are opposite and parallel, the movable stage is moved along the XY coordinate system grid of a set size at a set speed, and the peak reading of the fluorescence detector is synchronously monitored, and the second absolute coordinate (x2, y2) of the movable stage when the peak reading appears is recorded, it also includes:

[0017] Adjusting the low-magnification lens and making the field center of the low-magnification lens coincide with the sample center identification mark and the spot center identification mark, so as to complete the first precision alignment operation;

[0018] Switching the high-magnification lens to above the object surface, adjusting the relative position relationship between the high-magnification lens and the movable stage so that the lens plane of the high-magnification lens and the object surface are opposite and parallel, and focusing the high-magnification lens;

[0019] If the field center of the high-magnification lens does not overlap with the sample center identification mark and the light spot center identification mark, the high-magnification lens is adjusted again to make the field center of the high-magnification lens overlap with the sample center identification mark and the light spot center identification mark to complete the second precision alignment operation, and then the fluorescence detector is switched to the top of the object surface, and the fluorescence detector is adjusted so that its detection window is opposite and parallel to the object surface; wherein the second precision is higher than the first precision;

[0020] If the field center of the high-magnification lens coincides with the sample center identification mark and the light spot center identification mark, the fluorescence detector is directly switched to above the object surface and adjusted so that its detection window is opposite and parallel to the object surface.

[0021] In one embodiment, the step of repeatedly moving the movable stage at a set speed along an XY coordinate system grid of a set size and repeatedly calculating a maximum error coordinate value (Δx, Δy) between the center of the spot image and the center of the fluorescence detector until the maximum error coordinate value (Δx, Δy)=(0, 0) further includes:

[0022] Switch the high-magnification lens to the top of the object surface, and compensate the coordinates of the point to be measured according to the first absolute coordinates (x1, y1), move the stage to the compensated coordinate positions in sequence, and use the high-magnification lens to verify that the area to be measured with the point to be measured is located at the center of its field of view;

[0023] The fluorescence detector is switched to the upper part of the object surface, and the object stage is moved according to the compensated coordinate position to complete the automatic batch measurement after the first time.

[0024] In one embodiment, the step of determining the number of turns that the fluorescence detector needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy) includes:

[0025] The number of turns that the fluorescence detector needs to be adjusted along the X direction and the Y direction are Rx and Ry respectively, wherein Rx=Δx / s, Ry=Δy / s, and s is the pitch of the top screw of the clamping ring fixture used to fix the fluorescence detector.

[0026] In one embodiment, determining the number of turns that the detector needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy), and adjusting the detector according to the number of turns that need to be adjusted, includes:

[0027] The clamping ring fixture for fixing the fluorescence detector is a micrometer fixture. The detector is adjusted and twisted along the micrometer fixture according to the maximum error coordinate value (Δx, Δy), and twisted by Δx and Δy circles along the X direction and the Y direction respectively.

[0028] In one embodiment, the step of adjusting the low-magnification lens and making the field center of the low-magnification lens coincide with the sample center identification mark and the spot center identification mark includes:

[0029] The displacement of the low-magnification lens along the X direction and / or the Y direction is adjusted by the top screw of the clamp for fixing the low-magnification lens until the center of the field of view of the low-magnification lens coincides with the sample center identification mark and the spot center identification mark;

[0030] The step of adjusting the high-magnification lens and making the field center of the high-magnification lens coincide with the sample center identification mark and the spot center identification mark includes:

[0031] The displacement of the high-magnification lens along the X-direction and / or the Y-direction is adjusted by the top screw of the high-magnification lens fixing clamp until the field center of the high-magnification lens coincides with the sample center identification mark and the spot center identification mark.

[0032] In one embodiment, the moving the movable stage along an XY coordinate grid of a set size at a set speed comprises:

[0033] The movable stage is moved along a 100X100um XY coordinate grid at a speed of 10um / s.

[0034] In one embodiment, after the movable stage is moved so that the fluorescent sample placed on the stage surface is moved into the field of view of the low-magnification lens, the method further comprises:

[0035] The focusing of the low-magnification lens is completed by finely adjusting the displacement of the movable stage along the Z direction; wherein the X direction, the Y direction and the Z direction are perpendicular to each other.

[0036] The detector calibration and alignment method for X-ray wafer measurement provided by the present application has the following beneficial effects:

[0037] Compared with the prior art, the detector calibration and alignment method for X-ray wafer measurement provided in the present application, after the X-ray source excites a fluorescent spot in the visible light band on a fluorescent sample through X-rays, collects the spot image corresponding to the fluorescent spot and marks a spot center identification mark in the center of the spot image, thereby realizing the detector measurement of the patterned wafer, and the collection, identification and detector alignment process can be completed online and continuously to replace the offline measurement of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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 creative labor.

[0039] Figure 1 A flow chart of a detector calibration and alignment method for X-ray wafer measurement provided in an embodiment of the present application;

[0040] Figure 2 A schematic diagram of the spot center identification mark, the sample center identification mark and the field of view center of the lens before alignment provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of the alignment of the spot center identification mark, the sample center identification mark and the field of view center of the lens provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of a switching device involved in a workbench for detector calibration and alignment for X-ray wafer measurement provided in an embodiment of the present application;

[0043] Figure 5 for Figure 4 a coaxial front view of the stereoscopic schematic diagram shown;

[0044] Figure 6 for Figure 4A coaxial left view of the stereoscopic schematic diagram shown;

[0045] Figure 7 for Figure 1 A top view of the stereoscopic schematic diagram shown;

[0046] Figure 8 for Figure 1 Bottom view of the stereogram shown.

[0047] Among them, the reference numerals in the figure are:

[0048] 10. Rotating motor; 20. Turntable structure; 30. Detector; 50. Supporting beam; 60. Snap ring fixture; 70. Top screw; 201. Turntable body; 202. Supporting cantilever; 202a. First supporting cantilever; 202b. Second supporting cantilever; 202c. Third supporting cantilever; 401. Low-magnification lens; 402. High-magnification lens; 501. Connecting end; 502. Cantilever end; 601. First snap ring fixture; 602. Second snap ring fixture; 603. Third snap ring fixture; a. Fluorescent sample; b. Sample center identification mark; c. Field of view; d. Center of field of view; e. Spot image; f. Spot center identification mark. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0051] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0053] The detector calibration and alignment method for X-ray wafer measurement and the workbench involved provided in the embodiment of the present application are now described.

[0054] See also Figures 1 to 3 As shown, the detector 30 calibration and alignment method for X-ray wafer measurement provided in the embodiment of the present application includes:

[0055] 101. Switch the low-magnification lens 401 to above the object loading surface of the movable stage, and adjust the relative position relationship between the low-magnification lens 401 and the movable stage so that the lens plane of the low-magnification lens 401 and the object loading surface are opposite and parallel.

[0056] The movable stage, such as a tray or other stage, may preferably be an electric stage with a stroke greater than 12 inches. The stage may be pre-placed with the fluorescent sample a, or the fluorescent sample a may be placed after step 101 is completed.

[0057] The stage is provided with a vacuum channel, and the fluorescent sample a can be adsorbed and fixed on the stage by vacuum, and the low-magnification lens 401 is mounted directly above the stage through a switching device. The low-magnification lens 401, the high-magnification lens 402 and the fluorescent detector 30 of the embodiment of the present application are all mounted above the stage through a switching device, and the switching device can switch the low-magnification lens 401, the high-magnification lens 402 and the fluorescent detector 30 to the top of the stage through a turntable structure 20.

[0058] 102. Move the movable stage to move the fluorescent sample a placed on the loading surface to the field of view c of the low-magnification lens 401; wherein the fluorescent sample a is placed on the loading surface of the movable stage, and the center of the fluorescent sample a is marked with a sample center identification mark b.

[0059] 103. The low-magnification lens 401 is focused by fine-tuning the displacement of the movable stage along the Z direction; wherein the X direction, the Y direction and the Z direction are perpendicular to each other and constitute a spatial coordinate system.

[0060] 104. Use X-rays to excite a fluorescent spot in the visible light band on the fluorescent sample a, collect a spot image e corresponding to the fluorescent spot, and mark a spot center identification mark f at the center of the spot image e.

[0061] Among them, by turning on the X-ray source, X-rays with grazing incidence (very small incident angle) are used to excite a fluorescent spot in the visible light band on the fluorescent sample a. The spot image e corresponding to the fluorescent spot is an ellipse with a major-minor axis ratio greater than 20:1, which can be an open ellipse or a closed ellipse.

[0062] 105. Move the movable stage to make the sample center identification mark b and the light spot center identification mark f coincide with each other, and record the first absolute coordinate (x1, y1) of the movable stage when they coincide with each other;

[0063] 106. Adjust the low-magnification lens 401 and make the field center d of the low-magnification lens 401 coincide with the sample center identification mark b and the spot center identification mark f to complete the first precision alignment operation.

[0064] 107; switch the high magnification lens 402 to the top of the loading surface, adjust the relative position of the high magnification lens 402 and the movable loading stage so that the lens plane of the high magnification lens 402 and the loading surface are relative and parallel, and focus the high magnification lens 402;

[0065] 107a. If the field center d of the high-magnification lens 402 does not overlap with the sample center identification mark b and the light spot center identification mark f, the high-magnification lens 402 is adjusted again to make the field center d of the high-magnification lens 402 overlap with the sample center identification mark b and the light spot center identification mark f, so as to complete the second precision alignment operation, and then the fluorescence detector 30 is switched to the upper side of the object surface, and the fluorescence detector 30 is adjusted so that its detection window and the object surface are opposite and parallel; wherein the second precision is higher than the first precision;

[0066] 107b. If the field center d of the high-magnification lens 402 coincides with the sample center identification mark b and the light spot center identification mark f, the fluorescence detector 30 is directly switched to the top of the object surface, and the fluorescence detector 30 is adjusted so that its detection window and the object surface are opposite and parallel.

[0067] 108. Switch the fluorescence detector 30 to the top of the loading surface and make its detection window relative to and parallel to the loading surface, move the movable stage along the XY coordinate grid of set size at a set speed, and synchronously monitor the peak reading of the fluorescence detector 30, and record the second absolute coordinate (x2, y2) of the movable stage when the peak reading appears.

[0068] 109. Calculate the maximum error coordinate value (Δx, Δy) between the center of the spot image e and the center of the fluorescence detector 30, determine the number of turns that the fluorescence detector 30 needs to be adjusted along the X and Y directions according to the maximum error coordinate value (Δx, Δy), and adjust the fluorescence detector 30 according to the number of turns that need to be adjusted; wherein, (Δx, Δy) = (x2, y2) - (x1, y1).

[0069] 110. Repeatedly move the movable stage along the XY coordinate system grid of a set size at a set speed, and repeatedly calculate the maximum error coordinate value (Δx, Δy) between the center of the spot image e and the center of the fluorescence detector 30 until the maximum error coordinate value (Δx, Δy) = (0, 0).

[0070] The detector 30 calibration and alignment method for X-ray wafer measurement provided in the embodiment of the present application, after the X-ray source excites a fluorescent spot in the visible light band on the fluorescent sample a through X-rays, by collecting the spot image e corresponding to the fluorescent spot and marking the spot center identification mark f at the center of the spot image e, the detector 30 can measure the pattern wafer, and the collection, identification and alignment process of the detector 30 can be completed online continuously to replace the offline measurement of the prior art. In addition, two different precision alignments are performed through different lenses with high and low magnifications, so that the calibration accuracy is higher.

[0071] 111. Switch the high-magnification lens 402 to the top of the object surface, and compensate the coordinates of the point to be measured according to the first absolute coordinates (x1, y1), and move the stage to the compensated coordinate positions in sequence, and use the high-magnification lens 402 to verify that the area to be measured with the point to be measured is located at the center d of its field of view;

[0072] 112. Switch the fluorescence detector 30 to the top of the loading surface, and move the loading stage according to the compensated coordinate position to complete the automatic batch measurement after the first time.

[0073] Through the above steps 111 and 112, batch measurement after the first time can be achieved.

[0074] In one embodiment, the above-mentioned acquisition of the spot image e corresponding to the fluorescent spot and marking the spot center identification mark f in the center of the spot image e includes: using an industrial camera and cooperating with a low-magnification lens 401 to acquire the spot image e corresponding to the fluorescent spot in real time, using a template matching algorithm to identify the spot image e and marking the spot center identification mark f in the center of the spot image e.

[0075] In one embodiment, the method of determining the number of turns that the fluorescence detector 30 needs to be adjusted along the X and Y directions based on the maximum error coordinate values ​​(Δx, Δy) includes: the number of turns that the fluorescence detector 30 needs to be adjusted along the X and Y directions are Rx and Ry, respectively, where Rx = Δx / s, Ry = Δy / s, and s is the pitch of the top screw 70 of the clamp 60 used to fix the fluorescence detector 30.

[0076] In another embodiment, the above-mentioned method of determining the number of turns that the detector 30 needs to be adjusted along the X and Y directions based on the maximum error coordinate value (Δx, Δy), and adjusting the detector 30 according to the number of turns that need to be adjusted, includes: the retaining ring clamp 60 used to fix the fluorescence detector 30 is a micrometer clamp, and the detector 30 is adjusted and twisted along the micrometer clamp according to the maximum error coordinate value (Δx, Δy), and is twisted Δx and Δy turns along the X and Y directions respectively.

[0077] In one embodiment, the above-mentioned adjustment of the low-magnification lens 401 so that the field center d of the low-magnification lens 401 coincides with the sample center identification mark b and the light spot center identification mark f includes: adjusting the displacement of the low-magnification lens 401 along the X direction and / or the Y direction through the top screw 70 of the clamping ring fixture 60 for fixing the low-magnification lens 401 until the field center d of the low-magnification lens 401 coincides with the sample center identification mark b and the light spot center identification mark f;

[0078] The above-mentioned adjustment of the high-magnification lens 402 and making the field center d of the high-magnification lens 402 coincide with the sample center identification mark b and the light spot center identification mark f include: adjusting the displacement of the high-magnification lens 402 along the X-direction and / or Y-direction by means of the top screw 70 of the clamp 60 for fixing the high-magnification lens 402 until the field center d of the high-magnification lens 402 coincides with the sample center identification mark b and the light spot center identification mark f.

[0079] In one embodiment, the moving of the movable stage at a set speed along an XY coordinate grid of a set size includes: moving the movable stage at a speed of 10 um / s along an XY coordinate grid of 100X100 um.

[0080] See also Figures 4 to 8 As shown, the working table provided in the embodiment of the present application for executing the above-mentioned detector calibration and alignment method for X-ray wafer measurement is provided with the above-mentioned movable stage, such as a tray or other carrier, which can preferably be an electric stage with a stroke greater than 12 inches. The stage is provided with a vacuum channel, by which the fluorescent sample can be adsorbed and fixed on the stage, and the switching device is arranged directly above the stage. The working position described in the following embodiments of the present application refers to the position directly above the stage, that is, the position where the fluorescent detector 30 described below and the stage are opposite in the vertical direction, and the position where the positioning lens 40 described below and the stage are opposite in the vertical direction.

[0081] like Figure 4 As shown, in the embodiment of the present application, the switching device includes a rotary motor 10, a turntable structure 20, a fluorescence detector 30, a low-magnification lens 401, and a high-magnification lens 402. The plane where the turntable structure 20 is located is parallel to the plane where the stage is located. The turntable structure 20 includes a turntable body 201 and at least two supporting cantilevers 202. The turntable body 201 is a ring structure. The turntable body 201 is coaxially connected to the rotating shaft of the rotary motor 10, and is provided to rotate relative to the workbench under the drive of the rotating shaft.

[0082] like Figure 8 As shown, one end of the support cantilever 202 is connected to the turntable body 201, and this end is preferably connected to the outer edge of the turntable body 201. The other end opposite to this end extends radially outward along the radial direction of the turntable body 201, and an angle is set between two adjacent support cantilever 202. The turntable structure 20 includes three support cantilever 202, namely, the first support cantilever 202a, the second support cantilever 202b and the third support cantilever 202c; the low magnification lens 401, the fluorescence detector 30 and the high magnification lens 402 are respectively arranged on the other ends of the first support cantilever 202a, the second support cantilever 202b and the third support cantilever 202c.

[0083] When the turntable body 201 rotates driven by the rotating shaft, the fluorescence detector 30, the low magnification lens 401 and the high magnification lens 402 can be switched to the set working position of the workbench in different time sequences under the drive of the turntable body 201. Preferably, the low magnification lens 401 is a low-magnification telecentric lens, and the high-magnification lens 402 is a high-magnification telecentric lens.

[0084] When the switching device provided by this embodiment is used to calibrate the sample, first, the rotating motor 10 is controlled to drive the turntable structure 20 to rotate, and the low-power telecentric lens is switched to the working position. At this time, the lens plane of the low-power telecentric lens is parallel to the loading surface of the stage. The fluorescent sample is placed on the loading surface of the stage, and the vacuum adsorption is turned on to fix the fluorescent sample. By moving the stage, the cross mark in the center of the fluorescent sample is moved to the field of view of the low-power telecentric lens, and the height of the stage along the vertical direction is fine-tuned to enable the camera attached to the low-power telecentric lens to complete the focus.

[0085] Turn on the X-ray source, and the X-rays with grazing incidence (extremely small incident angle) excite a fluorescent spot in the visible light band on the fluorescent sample. The shape of the fluorescent spot is elliptical, and the ratio of its major and minor axes is preferably greater than 20:1. Among them, the fluorescent spot can be a non-closed ellipse or a closed ellipse. Use the camera attached to the low-power telecentric lens to capture images in real time, and use the template matching algorithm to identify the elliptical fluorescent spot, and mark the center of the ellipse with a cross on the image. Move the stage again, move the cross mark in the center of the fluorescent sample to the center of the elliptical spot, so that the two cross marks coincide, and record the absolute coordinates of the stage at this time (x1, y1). Through the top screw 70 on the retaining ring clamp 60 corresponding to the low-power telecentric lens, fine-tune the lateral position and longitudinal position of the low-power telecentric lens in the horizontal plane until the center of the camera field of view coincides with the above-mentioned cross mark, and the rough alignment is completed.

[0086] By controlling the rotating motor 10 to drive the turntable structure 20, the high-power telecentric lens is switched to the working position. The position of the high-power telecentric lens in the vertical direction is fine-tuned by the top screw 70 on the retaining ring fixture 60 corresponding to the high-power telecentric lens to complete the focusing. At this time, if the center cross mark of the fluorescent sample is not at the center of the field of view of the high-power telecentric lens, the lateral position and longitudinal position of the high-power telecentric lens are fine-tuned in the horizontal plane by fine-tuning the top screw 70 on the retaining ring fixture 60 corresponding to the high-power telecentric lens, so that the center of its field of view coincides with the cross mark of the fluorescent sample, that is, the fine alignment is completed. By controlling the rotating motor 10 to drive the turntable structure 20 to rotate, the fluorescence detector 30 is switched to the working position, and at this time, the window plane of the fluorescence detector 30 is parallel to the loading surface of the stage.

[0087] At this point, the stage is moved along a 100X100um grid at a speed of 10um / s, while the peak reading of the fluorescence detector 30 is monitored, and the absolute coordinates (x2, y2) of the stage when the maximum reading appears are recorded. The maximum error between the center of the fluorescent spot and the center of the fluorescence detector 30 is calculated, that is, (Δx, Δy) = (x2, y2) - (x1, y1). According to the pitch of the top screw 70 of the clamping ring fixture 60 of the fluorescence detector 30, the number of turns (Rx, Ry) required to be tightened in the horizontal and longitudinal directions corresponding to (Δx, Δy) is calculated, that is, Rx is equal to Δx divided by the pitch, and Ry is equal to Δy divided by the pitch. Turn off the X-ray source and reversely tighten the top screw 70 of the clamping ring fixture 60 of the fluorescence detector 30 by the corresponding number of turns. Alternatively, the clamping ring fixture 60 here can use a micrometer, and according to the calculated Δx and Δy values, the micrometer can be tightened to the values ​​of Δx and Δy. Repeat the above steps of calibrating and aligning the fluorescence detector 30 until the error is zero, that is, (Δx, Δy) = (0, 0), that is, the calibration and calibration are completed, and the result can be used for subsequent measurement. It can be seen that the switching device provided in this embodiment can realize the measurement of patterned wafers.

[0088] In subsequent measurements, first, the high-power telecentric lens is switched to the working position through the turntable structure 20, and the coordinates of the test point are compensated according to the above-recorded spot center coordinates (x1, y1), and the stage is moved to the compensated coordinate positions in sequence. Use the high-power telecentric lens to verify whether the area to be measured is in the center of the field of view. If not, fine-tune the high-power telecentric lens through the top screw 70 until the area to be measured is in the center of the field of view. Switch the fluorescence detector 30 to the working position again by controlling the rotating motor 10, and move the stage in sequence according to the above-recorded coordinate points of the spot center, and then perform automated batch measurement.

[0089] like Figures 4 to 8 As shown, the switching device further includes a supporting crossbeam 50, which is higher than the table surface of the workbench and parallel to the table surface of the workbench. The supporting crossbeam 50 has a connecting end 501 and a cantilevering end 502 which are arranged opposite to each other. The connecting end 501 is used to connect to the workbench, and the rotating motor 10 and the turntable structure 20 are mounted on the cantilevering end 502. The cantilevering end 502 is suspended to cantilever the rotating motor 10, the turntable structure 20, the fluorescence detector 30 and the positioning lens 40 above the stage.

[0090] like Figure 4 and Figure 5 As shown, in one embodiment, a through hole structure is provided on the cantilever end 502 and penetrates the supporting beam 50 in the vertical direction. The rotating motor 10 and the turntable structure 20 are coaxial along the axis of the through hole structure and are arranged on both sides of the through hole structure. The turntable body 201 is rotatably connected to the supporting beam 50, and the rotating shaft passes through the through hole structure and is connected to the turntable body 201, thereby realizing the assembly of the rotating motor 10 and the turntable structure 20.

[0091] In a specific embodiment, the turntable body 201 has a disk shaft, which is coaxially connected to the rotating shaft. At least two hemispherical grooves are opened on the axial surface of the disk shaft, and three hemispherical grooves are opened on the axial surface of the disk shaft, and shifting balls are movably arranged in the hemispherical grooves; three hemispherical grooves are opened on the tube wall of the disk shaft sleeve, and the three hemispherical grooves of the disk shaft sleeve are respectively arranged opposite to the first supporting cantilever 202a, the second supporting cantilever 202b and the third supporting cantilever 202c, and the first supporting cantilever 202a, the second supporting cantilever 202b and the third supporting cantilever 202c are respectively shifted by three balls, that is, the low-magnification telecentric lens, the high-magnification telecentric lens and the fluorescence detector 30 are respectively shifted.

[0092] like Figures 1 to 5As shown, in the embodiment of the present application, the switching device further includes a snap ring fixture 60, and the fluorescence detector 30, the low-magnification lens 401 and the high-magnification lens 402 are all sleeved in a snap ring fixture 60, and the snap ring fixture 60 is respectively mounted on the other end of at least two supporting cantilevers 202. Among them, the snap ring fixture 60 is a common fixing method of existing lenses, and the snap ring fixture 60 has a top screw 70 that penetrates its wall thickness. The top screw 70 can move relative to the snap ring fixture 60 along the radial direction of the snap ring fixture 60, which is used to fix or fine-tune the position of the fluorescence detector 30 or the positioning lens 40 relative to the snap ring fixture 60.

[0093] Corresponding to the above-mentioned low-magnification lens 401 and high-magnification lens 402, in a preferred embodiment, the switching device includes three snap ring clamps 60, namely a first snap ring clamp 601, a second snap ring clamp 602 and a third snap ring clamp 603. The first snap ring clamp 601, the second snap ring clamp 602 and the third snap ring clamp 603 correspond to the first support cantilever 202a, the second support cantilever 202b and the third support cantilever 202c, respectively, and are respectively used for installing, fixing and fine-tuning the low-magnification lens 401, the fluorescence detector 30 and the high-magnification lens 402.

[0094] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A detector calibration and alignment method for X-ray wafer measurement, characterized in that: include: Switching the low-magnification lens (401) to the top of the object loading surface, and adjusting the relative position relationship between the low-magnification lens (401) and the movable object loading platform so that the lens plane of the low-magnification lens (401) and the object loading surface are opposite and parallel; Moving the movable stage to move the fluorescent sample (a) placed on the stage surface into the field of view (c) of the low-magnification lens (401); X-rays are used to excite a fluorescent spot in the visible light band on a fluorescent sample (a), a spot image (e) corresponding to the fluorescent spot is collected, and a spot center identification mark (f) is marked at the center of the spot image (e); wherein the fluorescent sample (a) is placed on a loading surface of a movable loading stage, and the center of the fluorescent sample (a) is marked with a sample center identification mark (b); Move the movable stage to make the sample center identification mark (b) and the light spot center identification mark (f) coincide with each other, and record the first absolute coordinates (x1, y1) of the movable stage when they coincide with each other; Adjusting the low-magnification lens (401) and making the field center (d) of the low-magnification lens (401) coincide with the sample center identification mark (b) and the light spot center identification mark (f), so as to complete a first precision alignment operation; Switching the high-magnification lens (402) to the position above the object loading surface, adjusting the relative position relationship between the high-magnification lens (402) and the movable object loading platform so that the lens plane of the high-magnification lens (402) and the object loading surface are opposite and parallel, and focusing the high-magnification lens (402); If the field center (d) of the high-magnification lens (402) does not overlap with the sample center identification mark (b) and the light spot center identification mark (f), the high-magnification lens (402) is adjusted again to make the field center (d) of the high-magnification lens (402) overlap with the sample center identification mark (b) and the light spot center identification mark (f) to complete the second precision alignment operation, and then the fluorescence detector (30) is switched to the top of the object surface, and the fluorescence detector (30) is adjusted so that its detection window is opposite to and parallel to the object surface; wherein the second precision is higher than the first precision; If the field of view center (d) of the high-magnification lens (402) coincides with the sample center identification mark (b) and the light spot center identification mark (f), the fluorescence detector (30) is directly switched to the top of the object loading surface, and the fluorescence detector (30) is adjusted so that its detection window is opposite to and parallel to the object loading surface; Switching the fluorescence detector (30) to the top of the loading surface, and making its detection window opposite and parallel to the loading surface, moving the movable loading stage along an XY coordinate system grid of a set size at a set speed, and synchronously monitoring the peak reading of the fluorescence detector (30), and recording the second absolute coordinate (x2, y2) of the movable loading stage when the peak reading occurs; Calculating the maximum error coordinate value (Δx, Δy) between the center of the light spot image (e) and the center of the fluorescence detector (30), determining the number of turns that the fluorescence detector (30) needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy), and adjusting the fluorescence detector (30) according to the number of turns that need to be adjusted; wherein (Δx, Δy)=(x2, y2)-(x1, y1); Repeating the steps of moving the movable stage at a set speed along an XY coordinate system grid of a set size, and repeatedly calculating a maximum error coordinate value (Δx, Δy) between the center of the light spot image (e) and the center of the fluorescence detector (30), until the maximum error coordinate value (Δx, Δy) = (0, 0); Switching the high-magnification lens (402) to the top of the object-carrying surface, and compensating the coordinates of the point to be measured according to the first absolute coordinates (x1, y1), and moving the object-carrying stage to the compensated coordinate positions in sequence, and using the high-magnification lens (402) to verify that the area to be measured with the point to be measured is located at the center of its field of view (d); The fluorescence detector (30) is switched to the upper part of the object loading surface, and the object loading stage is moved according to the compensated coordinate position to complete the automatic batch measurement after the first time.

2. The detector calibration and alignment method for X-ray wafer measurement according to claim 1, characterized in that: The step of collecting the spot image (e) corresponding to the fluorescent spot and marking a spot center identification mark (f) at the center of the spot image (e) includes: An industrial camera is used in conjunction with a low-magnification lens (401) to collect a spot image (e) corresponding to the fluorescent spot in real time, the spot image (e) is identified using a template matching algorithm, and a spot center identification mark (f) is marked at the center of the spot image (e).

3. The detector calibration and alignment method for X-ray wafer measurement according to claim 1, characterized in that: The step of determining the number of turns that the fluorescence detector (30) needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy) comprises: The number of turns that the fluorescence detector (30) needs to be adjusted along the X direction and the Y direction are Rx and Ry respectively, wherein Rx=Δx / s, Ry=Δy / s, and s is the pitch of the top screw (70) of the clamping ring fixture (60) used to fix the fluorescence detector (30).

4. The detector calibration and alignment method for X-ray wafer measurement according to claim 1, characterized in that: The method of determining the number of turns that the fluorescence detector (30) needs to be adjusted along the X direction and the Y direction according to the maximum error coordinate value (Δx, Δy), and adjusting the fluorescence detector (30) according to the number of turns that need to be adjusted, comprises: The clamping ring fixture (60) for fixing the fluorescence detector (30) is a micrometer fixture. The fluorescence detector (30) is adjusted and twisted along the micrometer fixture according to the maximum error coordinate value (Δx, Δy), and is twisted by Δx and Δy circles respectively along the X direction and the Y direction.

5. The detector calibration and alignment method for X-ray wafer measurement according to claim 1, characterized in that: The step of adjusting the low-magnification lens (401) and making the field center (d) of the low-magnification lens (401) coincide with the sample center identification mark (b) and the light spot center identification mark (f), comprises: The displacement of the low-magnification lens (401) along the X direction and / or the Y direction is adjusted by means of a top screw (70) of a clamp (60) for fixing the low-magnification lens (401) until the center (d) of the field of view of the low-magnification lens (401) coincides with the sample center identification mark (b) and the light spot center identification mark (f); The step of adjusting the high-magnification lens (402) and making the field center (d) of the high-magnification lens (402) coincide with the sample center identification mark (b) and the light spot center identification mark (f), comprises: The displacement of the high-magnification lens (402) along the X direction and / or the Y direction is adjusted by means of a top screw (70) of a clamp (60) for fixing the high-magnification lens (402) until the field center (d) of the high-magnification lens (402) coincides with the sample center identification mark (b) and the light spot center identification mark (f).

6. The detector calibration and alignment method for X-ray wafer measurement according to claim 1, characterized in that: The method of moving the movable stage at a set speed along an XY coordinate grid of a set size comprises: The movable stage is moved along a 100 x 100 um XY coordinate grid at a speed of 10 um / s.

7. The detector calibration and alignment method for X-ray wafer measurement according to claim 2, characterized in that: After the movable stage is moved so that the fluorescent sample (a) placed on the stage surface is moved into the field of view (c) of the low-magnification lens (401), the method further comprises: The focusing of the low-magnification lens (401) is completed by finely adjusting the displacement of the movable stage along the Z direction; wherein the X direction, the Y direction and the Z direction are perpendicular to each other.

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