Detection device and grating detection method thereof

Abstract

The invention discloses a detection device and a grating detection method thereof, and relates to the technical field of grating detection.The detection device comprises a light source module, a diaphragm module and a sample fixing module, and the light source module is used for emitting light; the diaphragm module comprises a diaphragm, and the diaphragm is movably arranged on the light emitting side of the light source module; the sample fixing module is arranged between the light source module and the diaphragm module, and is used for loading a to-be-tested grating and adjusting the direction of the to-be-tested grating relative to the light source module, so that the light is transmitted out of a to-be-tested point of the to-be-tested grating, and a test light spot is formed on the diaphragm module; according to the technical scheme provided by the invention, the detection device capable of realizing nondestructive measurement of periodic manufacturing errors of the grating can be provided.

Description

Technical Field

[0001] The present invention relates to the technical field of grating detection, and in particular to a detection device and a grating detection method thereof. Background Art

[0002] In the grating manufacturing process, due to certain errors in the adjustment and control accuracy of the manufacturing equipment, when manufacturing large-area gratings, the characteristic dimensions such as the width and height of the grating lines may have specific deviations from the ideal design values ​​every several cycles, thus forming periodic manufacturing errors of the grating.

[0003] In the related art, the grating structure is often inspected by a scanning electron microscope. Since the scanning electron microscope needs to irradiate the grating to be tested with an electron beam during the inspection process, and the energy of the electron beam will cause irreversible damage to the photoresist of the grating, it is impossible to achieve non-destructive measurement during the inspection. Summary of the invention

[0004] The main purpose of the present invention is to propose a detection device and a grating detection method thereof, aiming to provide a detection device that can realize non-destructive measurement of periodic manufacturing errors of gratings.

[0005] To achieve the above object, the detection device proposed by the present invention comprises:

[0006] A light source module, the light source module is used to emit light;

[0007] An aperture module, the aperture module comprising an aperture, the aperture being movably arranged on the light-emitting side of the light source module; and

[0008] A sample fixing module is arranged between the light source module and the aperture module, and is used for loading the grating to be measured and adjusting the orientation of the grating to be measured relative to the light source module so that the light is transmitted through different points to be measured of the grating to be measured and forms a test light spot on the aperture module.

[0009] In one embodiment, the aperture module comprises:

[0010] The diaphragm is provided with an annular slit, and the diaphragm and the grating to be measured are arranged in parallel; and

[0011] An aperture carrier is connected to the aperture drive and is used to drive the aperture to move relative to the light source module in a direction parallel to the grating to be tested, so that the annular slit and the test light spot are aligned and matched.

[0012] In one embodiment, the aperture comprises:

[0013] A first aperture portion, wherein the first aperture portion is arranged in a circular shape; and

[0014] A second aperture portion, the second aperture portion is arranged in an annular shape and is arranged around the first aperture portion to form the annular slit together with the first aperture portion;

[0015] The outer diameter of the first aperture part is adjustable, and the inner diameter of the second aperture part is adjustable, so that the annular slit is aligned with the test light spot.

[0016] In one embodiment, the detection device further comprises a detection module, and the detection module is arranged on a side of the aperture module away from the light source module.

[0017] The detection module includes at least two photoelectric detectors, and a plurality of the photoelectric detectors are sequentially spaced apart along the circumference of the annular slit.

[0018] In one embodiment, the light source module includes a light source and a light source holder, the light source is used to emit light, and the light source holder is drivingly connected to the light source to adjust the emission direction of the light source;

[0019] And / or, the sample fixing module comprises a sample fixing fixture and a sample carrier, the sample fixing fixture is used to install the grating to be measured, and the sample carrier is drivingly connected to the sample fixing fixture to adjust the orientation of the grating to be measured relative to the light source module;

[0020] And / or, at least one of the sample fixing module and the aperture module can be movably arranged along the arrangement direction of the sample fixing module and the aperture module.

[0021] The present invention further provides a grating detection method, which is applied to any of the grating detection devices described above, wherein the grating detection device comprises a light source module, a sample fixing module and an aperture module, and the detection method comprises the following steps:

[0022] Loading the grating to be measured on the sample fixing module;

[0023] Turning on the light source module to emit light to different test points of the grating to be tested, so as to obtain a test light spot located on the aperture of the aperture module;

[0024] It is determined whether the grating to be measured has periodic manufacturing errors according to the position information of the target light spot.

[0025] In one embodiment, the step of determining whether the grating to be tested has a periodic manufacturing error according to the position of the target light spot further includes:

[0026] Determining the position information of the reference light spot according to the main light emitted by the light source module;

[0027] Comparing the position information of the test light spot and the reference light spot;

[0028] If the position information of the target light spot is the same as the position information of the reference light spot, it is determined that the grating to be tested is normal;

[0029] If the position information of the target light spot is different from the position information of the reference light spot, it is determined that there is a periodic manufacturing error in the grating to be measured.

[0030] In one embodiment, after the step of determining that the grating to be tested has periodic manufacturing errors, the method further includes:

[0031] According to the position information of the target light spot and the reference light spot, the period of the periodic manufacturing error of the grating to be measured is calculated, and the calculation formula is:

[0032] Wherein, d0 represents the period of the periodic manufacturing error of the grating to be measured, λ0 represents the wavelength of the light of the light source module, a represents the distance between the target light spot and the reference light spot, and D represents the distance between the target light spot and the grating to be measured.

[0033] In one embodiment, after the step of calculating the period of the periodic manufacturing error of the grating to be measured according to the position information of the target light spot and the reference light spot, the method further comprises:

[0034] Changing the wavelength of light of the light source module, and calculating a plurality of periodic values ​​of the periodic manufacturing error of the grating to be measured corresponding to different light wavelengths;

[0035] The average value is calculated according to multiple period values ​​of the periodic manufacturing error of the grating to be measured corresponding to different light wavelengths to obtain the period of the periodic manufacturing error of the grating to be measured.

[0036] In one embodiment, the step of turning on the light source module and emitting light to different test points of the grating to be tested to obtain a test light spot located on the aperture of the aperture module further includes:

[0037] Turning on the light source module;

[0038] Calibrate the test optical path so that the light emitted by the light source is vertically incident on the surface of the grating to be tested, and the main emitted light of the light source is aligned with the center of the aperture;

[0039] The grating to be tested is moved to a position to be tested to obtain a test light spot on the aperture of the aperture module.

[0040] The technical solution of the present invention detects the grating to be tested by using a detection device, the detection device includes a light source module, a sample fixing module and an aperture module, wherein the sample fixing module is used to load the grating to be tested and adjust the orientation of the grating to be tested relative to the light source module, so that the light emitted by the light source module can form a corresponding test spot at the aperture module after being transmitted from different test points on the grating to be tested. Specifically, if the test point of the grating to be tested is normal, the light emitted by the light source module can only form a main diffraction spot on the aperture in the same direction as the incident direction of the light; if there is a periodic manufacturing error at the test point of the grating to be tested, the light emitted by the light source module will be abnormally diffracted due to the periodic manufacturing error on the grating, thereby forming a diffraction noise spot on the aperture whose position is offset from the main diffraction spot, thereby judging whether the grating has a periodic manufacturing error through the position information of the test spot obtained by the test. During the detection process of the detection device, the light emitted by the light source module can be transmitted through the grating without causing damage to the photoresist of the grating, thereby achieving non-destructive measurement of the grating during the detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0042] Figure 1 A schematic structural diagram of an embodiment of a detection device provided by the present invention;

[0043] Figure 2 for Figure 1 Partial structural diagram of the detection device;

[0044] Figure 3 is a flow chart of a first embodiment of a grating detection method of the present invention;

[0045] Figure 4 It is a partial flow chart of the second embodiment of the grating detection method of the present invention;

[0046] Figure 5 is a flow chart of a third embodiment of a grating detection method according to the present invention;

[0047] Figure 6 is a flow chart of a fourth embodiment of a grating detection method according to the present invention;

[0048] Figure 7 This is a partial flow chart of the fifth embodiment of the grating detection method of the present invention.

[0049] Description of Figure Numbers:

[0050] 100, detection device; 10, light source module; 11, light source; 12, light source carrier; 20, aperture module; 21, aperture; 211, first aperture part; 212, second aperture part; 213, annular slit; 22, aperture carrier; 30, sample fixing module; 31, sample fixing tool; 32, sample carrier; 40, detection module; 41, photoelectric detector;

[0051] 200. Grating to be measured.

[0052] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0055] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] In the grating manufacturing process, due to certain errors in the adjustment and control accuracy of the manufacturing equipment, when manufacturing large-area gratings, the characteristic dimensions such as the width and height of the grating lines may have specific deviations from the ideal design values ​​every few cycles, thereby forming periodic manufacturing errors of the grating. Among them, the periodic manufacturing errors of the grating can specifically include periodic line width errors and misalignment errors.

[0057] In the related art, the grating structure is often inspected by a scanning electron microscope. Since the scanning electron microscope needs to irradiate the grating to be tested with an electron beam during the inspection process, and the energy of the electron beam will cause irreversible damage to the photoresist of the grating, it is impossible to achieve non-destructive measurement during the inspection.

[0058] To this end, the present invention provides a detection device 100 .

[0059] See also Figure 1 and Figure 2 In one embodiment of the present invention, the detection device 100 includes:

[0060] A light source module 10, wherein the light source module 10 is used to emit light;

[0061] An aperture module 20, wherein the aperture module 20 comprises an aperture 21, and the aperture 21 is movably disposed on the light-emitting side of the light source module 10; and

[0062] The sample fixing module 30 is arranged between the light source module 10 and the aperture module 20, and is used for loading the grating 200 to be tested and adjusting the orientation of the grating 200 to be tested relative to the light source module 10, so that the light can be transmitted through different test points of the grating 200 to be tested and form a test spot on the aperture module 20.

[0063] Among them, the light source module 10 may include a laser for emitting laser toward the grating to be measured 200 on the sample fixing module 30, and the laser can be transmitted through the grating to be measured 200; further, when the laser is transmitted from the grating to be measured 200 and transmitted to the aperture 21 of the aperture module 20, a test spot can be formed on the aperture 21.

[0064] Specifically, if the test point of the grating 200 to be tested is normal, the light emitted by the light source module 10 can only form a main diffraction spot on the aperture 21 that is in the same direction as the incident direction of the light; if there is a periodic manufacturing error at the test point of the grating 200 to be tested, the light emitted by the light source module 10 will produce abnormal diffraction orders due to the periodic manufacturing errors on the grating, thereby generating periodically arranged stray light noise, thereby forming a diffraction noise spot on the aperture 21 whose position is offset from the main diffraction spot.

[0065] Therefore, it can be understood that the technical solution of the present invention can determine whether there is a periodic manufacturing error in the grating by the position information of the test light spot obtained by the test. Since the light emitted by the light source module 10 of the detection device 100 can be transmitted from the grating 200 to be tested during the detection process without causing damage to the photoresist of the grating 200 to be tested, non-destructive measurement of the grating 200 to be tested can be achieved during the detection process.

[0066] See also Figure 1 and Figure 2 In an embodiment of the present invention, the aperture module 20 comprises:

[0067] The aperture 21 is provided with an annular slit 213, and the aperture 21 and the grating to be measured 200 are arranged in parallel; and

[0068] The aperture carrier 22 is drivingly connected to the aperture 21 and is used to drive the aperture 21 to move relative to the light source module 10 in a direction parallel to the grating 200 to be tested, so that the annular slit 213 and the test light spot are aligned and matched.

[0069] The aperture 21 is a screen structure, and the aperture carrier 22 may include a multi-axis driving mechanism, which is connected to the aperture 21 through the multi-axis driving mechanism. The multi-axis driving mechanism may have the function of multi-axis rotation and linear translation, and is used to adjust the position of the aperture 21 relative to the grating 200 to be measured.

[0070] Specifically, in some embodiments, the arrangement direction of the light source module 10, the sample fixing module 30 and the aperture module 20 is defined as a first direction, and the aperture carrier 22 can be used to drive the aperture 21 to be movably arranged along the first direction, so that the aperture 21 and the grating to be measured 200 can be close to or away from each other in the first direction, thereby realizing the adjustment of the spacing between the aperture 21 and the grating to be measured 200, so as to facilitate the calculation of the period of the periodic manufacturing error of the grating to be measured 200.

[0071] Furthermore, the aperture carrier 22 may also include a multi-axis driving mechanism, which is connected to the aperture 21 by driving, and can utilize the multi-axis linear translation and rotation functions of the multi-axis driving mechanism to make the aperture 21 linearly translate in the first direction, the second direction, and the third direction, and can rotate around the third direction. Of course, the technical solution of the present invention is not limited thereto, and the aperture 21 can also be configured to perform more degrees of freedom of movement, and the specific implementation method can be configured according to actual needs.

[0072] It should be noted that when the light source 11 is incident vertically on the grating 200 to be measured, and the grating 200 to be measured and the aperture 21 of the aperture module 20 are parallel to each other, the diffraction noise spot caused by the periodic manufacturing error on the grating 200 to be measured will be offset on the aperture 21 relative to the main diffraction spot in the same direction as the incident direction of the light; when the number of diffraction noise spots is a plurality, the plurality of diffraction noise spots are sequentially spaced along the circumference of the main diffraction spot, and the spacing between each diffraction noise spot and the main diffraction spot is equal. At this time, by aligning the incident direction of the light with the center position of the annular slit 213, the plurality of diffraction noise spots can be evenly distributed at the annular slit 213.

[0073] It can be understood that by setting the annular slit 213 and making the radial width of the annular slit 213 match the width of the diffraction noise spot that needs to be aligned, on the one hand, it is convenient to set the photodetector 41 at the annular slit 213 to further test the spot, and on the other hand, it is beneficial to improve the signal-to-noise ratio during the test process, thereby helping to improve the detection sensitivity of the photodetector 41.

[0074] In some embodiments, the grating 200 to be measured and the aperture 21 can both be arranged in a vertical plane and arranged opposite to each other in the horizontal direction. The light source 11 can emit light toward the grating 200 to be measured in the horizontal direction, so that the light is transmitted to the grating 200 to be measured and the aperture 21 in sequence, and a corresponding test light spot is formed on the aperture 21. Such an arrangement can facilitate the installation and position calibration of the grating 200 to be measured and the aperture 21. In addition, the grating 200 to be measured and the aperture 21 to be measured are arranged opposite to each other in the horizontal direction, which is also conducive to reducing the space occupied by the detection device 100 in the vertical direction.

[0075] See also Figure 2 In an embodiment of the present invention, the aperture 21 comprises:

[0076] A first aperture portion 211, wherein the first aperture portion 211 is arranged in a circular shape; and

[0077] The second aperture portion 212 is arranged in an annular shape and is arranged around the first aperture portion 211 to form the annular slit 213 together with the first aperture portion 211;

[0078] The outer diameter of the first aperture portion 211 is adjustable, and the inner diameter of the second aperture portion 212 is adjustable, so that the annular slit 213 is aligned with the test light spot.

[0079] Among them, by increasing the outer diameter of the first aperture part 211 and the inner diameter of the second aperture part 212 synchronously, the size of the annular slit 213 can be increased and moved in the direction from the center to the periphery of the aperture 21; similarly, by decreasing the outer diameter of the first aperture part 211 and the inner diameter of the second aperture part 212 synchronously, the size of the annular slit 213 can be decreased and moved in the direction from the periphery to the center of the aperture 21. In this way, the position adjustment of the annular slit 213 on the aperture 21 can be achieved, so that the annular slit 213 can be moved to correspond to the test light spots at different positions, which is conducive to improving the test flexibility of the detection device 100.

[0080] By keeping the size of one of the outer diameter of the first aperture portion 211 and the inner diameter of the second aperture portion 212 unchanged and adjusting the size of the other, the width of the annular slit 213 in the radial direction can be adapted to the width of the diffraction noise light spot in the test light spot, thereby facilitating the improvement of the signal-to-noise ratio during the test. Of course, the width of the annular slit 213 in the radial direction can also be adjusted by adjusting the size of the outer diameter of the first aperture portion 211 and the inner diameter of the second aperture portion 212 to different degrees, which is not limited here.

[0081] See also Figure 1 and Figure 2 In an embodiment of the present invention, the detection device 100 further includes a detection module 40, and the detection module 40 is disposed on a side of the aperture module 20 away from the light source module 10.

[0082] The detection module 40 includes at least two photoelectric detectors 41 , and a plurality of the photoelectric detectors 41 are sequentially spaced apart along the circumference of the annular slit 213 .

[0083] It can be understood that when the light source 11 is incident vertically on the grating 200 to be measured, and the main emitted light of the light source 11 is aligned with the center of the aperture 21, and the grating 200 to be measured and the aperture 21 of the aperture module 20 are parallel to each other, if the grating 200 to be measured has a periodic manufacturing error, a diffraction noise spot will be generated at a position where the aperture 21 deviates from its center. At this time, when the number of diffraction noise spots is a certain number, the certain diffraction noise spots are distributed at intervals around the center of the aperture 21, and the distance between each diffraction noise spot and the center of the aperture 21 is equal, and can be distributed correspondingly at the annular slit 213. At this time, by sequentially arranging a plurality of photodetectors 41 at intervals along the circumference of the annular slit 213, and aligning each photodetector 41 with a diffraction noise spot in the test spot during the detection process, the light intensity detection of the corresponding spot can be achieved. Among them, the photodetector 41 can be, but is not limited to, set as an optical power meter.

[0084] Specifically, the number of diffraction noise spots is related to the type of periodic manufacturing error of the grating 200 to be measured, and the distribution orientation of the diffraction noise spots on the aperture 21 is related to the azimuth angle of the grating 200 to be measured relative to the light source 11. For example, two diffraction noise spots are formed, and the two diffraction noise spots are spaced apart in the vertical direction; or the diffraction noise spots can be as follows Figure 2 As shown, four diffraction noise spots are formed, of which two are spaced apart in the vertical direction, and the other two are spaced apart in the horizontal direction, etc.; alternatively, the number of diffraction noise spots and their distribution orientation on the aperture 21 can also be set in other ways, which are not limited here.

[0085] See also Figure 1 In an embodiment of the present invention, the light source module 10 includes a light source 11 and a light source holder 12 . The light source 11 is used to emit light. The light source holder 12 is drivingly connected to the light source 11 to adjust the emission direction of the light source 11 .

[0086] The light source carrier 12 may include a multi-axis driving mechanism to be connected to the light source 11 through the multi-axis driving mechanism. The multi-axis driving mechanism may have the functions of multi-axis linear translation and rotation, and is used to adjust the position of the light source 11 and the emission angle of the light of the light source 11, so as to improve the adjustment flexibility of the light source 11 and provide convenience for the testing process of the detection device 100.

[0087] Specifically, in some embodiments, the arrangement direction of the light source module 10, the sample fixing module 30 and the aperture module 20 is defined as the first direction, the vertical direction is defined as the second direction, and the direction perpendicular to the first direction and the second direction is defined as the third direction. The light source 11 can be linearly translated in the second direction and the third direction, so that the light source 11 can move in a vertical plane relative to the grating to be measured 200, and emit light toward different points to be measured of the grating to be measured 200.

[0088] Furthermore, the light source 11 can also rotate around the second direction and the third direction to adjust the pitch angle and the rotation angle of the light source 11 respectively, thereby adjusting the light emission direction of the light source 11. Of course, the technical solution of the present invention is not limited to this, and the light source 11 can also be set to move with more degrees of freedom, and the specific implementation method can be set according to actual needs.

[0089] See also Figure 1 In an embodiment of the present invention, the sample fixing module 30 includes a sample fixing fixture 31 and a sample carrier 32, the sample fixing fixture 31 is used to install the grating to be measured 200, and the sample carrier 32 and the sample fixing fixture 31 are drivingly connected to adjust the orientation of the grating to be measured 200 relative to the light source module 10.

[0090] The sample carrier 32 may include a multi-axis driving mechanism to drive and connect the multi-axis driving mechanism and the sample fixing fixture 31. The multi-axis driving mechanism may have the functions of multi-axis linear translation and rotation to improve the adjustment flexibility of the light source 11 and facilitate the test process of the detection device 100. The sample fixing fixture 31 may be configured to be detachably connected to the sample carrier so as to be customized and replaced according to actual conditions, so as to adapt to different gratings 200 to be tested.

[0091] Specifically, in some embodiments, the sample fixing fixture 31 can be linearly translated in a first direction to move toward or away from the aperture module 20 to achieve the spacing adjustment between the grating 200 to be measured and the aperture 21; the sample fixing fixture 31 can also be linearly translated in a second direction and a third direction to enable it to move in a vertical plane relative to the light source 11, so that different points to be measured on the grating 200 to be measured can be moved to the light emitting path of the light.

[0092] Furthermore, the sample fixing fixture 31 can also rotate around the first direction. It can be understood that the grating 200 to be tested includes a plurality of parallel grating lines, so that the grating 200 to be tested can be driven to rotate around the first direction to synchronously rotate, thereby adjusting the azimuth of the grating 200 to be tested relative to the light source 11, and changing the arrangement direction of the grating lines, thereby changing the distribution direction of the test light spot on the aperture 21. Of course, the technical solution of the present invention is not limited to this, and the sample fixing fixture 31 can also be set to move with more degrees of freedom, and the specific implementation method can be set according to actual needs.

[0093] See also Figure 1 In an embodiment of the present invention, at least one of the sample fixing module 30 and the aperture module 20 is movably disposed along an arrangement direction of the sample fixing module 30 and the aperture module 20 .

[0094] Among them, as in the above-mentioned embodiment, the sample carrier 32 may include a multi-axis driving mechanism, and the multi-axis driving mechanism may be connected to the sample fixing fixture 31 for driving, so as to achieve the function of linear translation of the sample fixing fixture 31 in the first direction; or, as in the above-mentioned embodiment, the aperture carrier 22 of the aperture module 20 may include a multi-axis driving mechanism, and the multi-axis driving mechanism may be connected to the aperture 21 for driving, so as to achieve the function of linear translation of the aperture 21 in the first direction; of course, it is also possible that both the sample carrier 32 and the aperture module 20 include a multi-axis driving mechanism, so as to achieve the function of linear translation of the aperture 21 and the grating 200 to be measured in the first direction. With such an arrangement, the spacing adjustment of the grating 200 to be measured and the aperture 21 can be achieved, which is not limited here.

[0095] Of course, the technical solution of the present invention is not limited thereto. In some embodiments, the detection device 100 further includes a base, and the sample fixing module 30 and the aperture module 20 are arranged on the base at intervals along the first direction. In addition, at least one of the sample fixing module 30 and the aperture module 20 can be movably arranged relative to the base as a whole, and is used for linear translation relative to the base along the first direction. In this way, the spacing adjustment between the grating 200 to be measured and the aperture 21 can also be achieved. The specific implementation method can be set according to actual needs and is not limited here.

[0096] Based on the structure of the above detection device 100 , the present invention further proposes a grating detection method applied to the detection device 100 .

[0097] like Figure 3 FIG. 1 is a flow chart of a first embodiment of a grating detection method according to the present invention. In this embodiment, the grating detection method comprises the following steps:

[0098] S100, loading the grating 200 to be tested on the sample fixing module 30;

[0099] S200, turning on the light source module 10, emitting light to different test points of the grating 200 to obtain a test light spot on the aperture 21 of the aperture module 20;

[0100] S300, determining whether the grating 200 to be tested has periodic manufacturing errors according to the position information of the target light spot.

[0101] In this embodiment, a grating detection system is formed by using a sample fixing module 30, a light source module 10 and an aperture module 20, and the grating 200 to be tested can be loaded through the sample fixing fixture 31 of the sample fixing module 30. After starting the detection, the sample fixing module 30 and the light source module 10 can be controlled to move relative to each other to adjust the relative orientation of the grating 200 to be tested and the light source 11, so that the light emitted by the light source 11 can be incident on different positions of the grating 200 to be tested, so that different test points of the grating 200 to be tested can be tested, and the position information of the test light spots corresponding to different test points can be obtained through the aperture 21 of the aperture module 20.

[0102] Among them, the test light spot refers to all the light spots formed on the aperture 21 when the light is transmitted through the test point of the grating 200 to be tested. The obtained test light spot can be one or more; the target light spot can be understood as a single light spot specified from the test light spot. Specifically, when the target light spot is in the same direction as the main incident direction of the light, the light spot is the main diffraction light spot; when the obtained target light spot deviates from the main incident direction of the light, the light spot is the diffraction noise light spot generated due to the periodic manufacturing error on the grating. After starting the test, the light source module 10 is turned on first, and the light of the light source module 10 is used to illuminate different test points of the grating 200 to be tested in turn, and the position information of the target light spot during the entire detection process is recorded to determine whether there is a diffraction noise light spot in the obtained target light spot, thereby determining whether there is a periodic manufacturing error in the grating 200 to be tested.

[0103] like Figure 4 FIG. 1 is a partial flow chart of the second embodiment of the grating detection method of the present invention. The other steps in this embodiment are similar to those in FIG. Figure 3 The steps in the embodiment shown are the same. The difference between this embodiment and the first embodiment is that step S300 in the aforementioned embodiment, i.e., the step of "determining whether the grating 200 to be tested has a periodic manufacturing error according to the position of the target light spot", can specifically include:

[0104] S310, determining position information of a reference light spot according to the main light emitted by the light source module 10;

[0105] S320, comparing the position information of the test light spot and the reference light spot;

[0106] S330, if the position information of the target light spot is the same as the position information of the reference light spot, it is determined that the grating 200 to be tested is normal;

[0107] S340: If the position information of the target light spot is different from the position information of the reference light spot, it is determined that the grating 200 to be tested has a periodic manufacturing error.

[0108] The reference light spot refers to the main diffraction light spot in the same direction as the main incident direction of the light; when the main light emitted by the light source 11 is aligned with the center of the aperture 21 of the aperture module 20, the reference light spot is located at the center of the aperture 21. Then, all the obtained light spots are compared with the reference light spots one by one to determine whether there is a periodic manufacturing error in the grating 200 to be tested.

[0109] In some embodiments, in order to facilitate the acquisition of the position information of the light spot, for example, in order to measure the distance D between the target light spot and the grating 200 to be measured, the aperture 21 of the aperture module 20 may be provided with a scale extending from the center to the edge thereof, so as to assist the user in measuring the radius length of the position of each light spot on the aperture 21; further, the aperture 21 of the aperture module 20 may be provided with an angle ruler, so as to assist the user in measuring the azimuth of the position of each light spot on the aperture 21 relative to the center of the aperture 21. Such a configuration can facilitate the measurement of the light spot position information in the grating detection process.

[0110] Of course, the technical solution of the present invention is not limited to this. In some embodiments, an image acquisition module may also be provided to photograph and identify the test light spot position on the aperture module 20, and thereby obtain the position information of the test light spot. In this way, it is helpful to improve the convenience and accuracy of obtaining the light spot position information. The specific implementation method can be set according to actual needs and is not limited here.

[0111] like Figure 5 , which is a flow chart of the third embodiment of the grating detection method of the present invention. The difference between this embodiment and the second embodiment is that after step S300 in the aforementioned embodiment, i.e., the step of "determining whether the grating to be detected 200 has periodic manufacturing errors", it also includes:

[0112] S400, calculating the period of the periodic manufacturing error of the grating 200 to be measured according to the position information of the target light spot and the reference light spot, and the calculation formula is:

[0113] Wherein, d0 represents the period of the periodic manufacturing error of the grating 200 to be measured, λ0 represents the wavelength of the light of the light source module 10 , a represents the distance between the target light spot and the reference light spot, and D represents the distance between the target light spot and the grating 200 to be measured.

[0114] Among them, at least one of the sample fixing fixture 31 of the sample fixing module 30 and the aperture 21 of the aperture module 20 can be linearly translated in the first direction to realize the adjustment of the distance D between the target light spot and the grating 200 to be measured, and the values ​​of the distance a between the target light spot and the reference light spot and the distance D between the target light spot and the grating 200 to be measured can both be real-time actual measurement values ​​measured during grating detection; the light source 11 of the light source module 10 can be set to a single-wavelength light source 11, and the value of the wavelength of its light can be a preset value, or the light source module 10 can switch the light source 11 used by it among multiple single-wavelength light sources 11, which is not limited here.

[0115] Furthermore, in some embodiments, the light intensity of the target light spot in the test light spot can also be measured, specifically, an annular slit 213 can be provided on the aperture 21, and an optical power meter or other types of photoelectric detectors 41 can be provided corresponding to the annular slit 213. The position and width of the annular slit 213 on the aperture 21 can be adjusted to match its position with the target light spot and to make its width the same as the width of the target light spot, thereby improving the signal-to-noise ratio during the test process, facilitating further detection and analysis of the periodic manufacturing error of the grating 200 to be tested, so as to quantitatively evaluate the severity of the grating error.

[0116] like Figure 6 , which is a flow chart of a fourth embodiment of the grating detection method of the present invention. The difference between this embodiment and the third embodiment is that, in the embodiment of the present invention, after the aforementioned step S400, i.e., the step of "calculating the period of the periodic manufacturing error of the grating 200 to be measured according to the position information of the target light spot and the reference light spot", it also includes:

[0117] S500, changing the wavelength of the light of the light source module 10, and calculating a plurality of periodic values ​​of the periodic manufacturing error of the grating 200 to be measured corresponding to different light wavelengths;

[0118] S600 , calculating an average value according to multiple period values ​​of the periodic manufacturing error of the grating 200 to be measured corresponding to different light wavelengths, to obtain the period of the periodic manufacturing error of the grating 200 to be measured.

[0119] In this embodiment, a cross-validation test can be performed by changing the wavelength of light of the light source module 10. Specifically, multiple tests can be performed to obtain position information of multiple groups of target light spots corresponding to different light wavelengths, and based on the position information of the diffraction noise light spots in each group of light spots, multiple periodic manufacturing error period values ​​can be calculated. By calculating the average value of multiple period values, the required period of the periodic manufacturing error of the grating 200 to be tested can be obtained, thereby improving the measurement accuracy of the manufacturing error period.

[0120] It should be noted that when testing with light sources 11 at different wavelengths, the diffraction direction of the grating will change accordingly due to the dispersion characteristics of the grating 200 to be tested. Therefore, when multiple tests are performed, the orientation of the annular slit 213 on the aperture module 20 can be adjusted accordingly during each test so that the diffraction noise spot in the resulting test spot can be aligned with the annular slit 213 to improve the signal-to-noise ratio during each test, thereby facilitating further detection and analysis of the periodic manufacturing errors of the grating 200 to be tested.

[0121] like Figure 7FIG. 1 is a partial flow chart of the fifth embodiment of the grating detection method of the present invention. The other steps in this embodiment are similar to those in FIG. Figure 3 In the embodiment of the present invention, the aforementioned step S200, i.e., the step of "turning on the light source module 10, emitting light to different test points of the grating 200 to be tested, and obtaining a test light spot on the aperture 21 of the aperture module 20", may specifically include:

[0122] S210, turning on the light source module 10;

[0123] S220, calibrating the test optical path, so that the light emitted by the light source 11 is vertically incident on the surface of the grating 200 to be tested, and the main emitted light of the light source 11 is aligned with the center of the aperture 21;

[0124] S230 , moving the grating 200 to be tested to a position to be tested, and obtaining a test light spot on the aperture 21 of the aperture module 20 .

[0125] Among them, by making the light emitted by the light source 11 vertically incident on the surface of the grating 200 to be tested, and making the main emitted light of the light source 11 align with the center of the aperture 21, the calibration of the test light path can be achieved. At this time, the proposed reference light spot is located at the center of the aperture 21, and the main diffraction light spot generated by the main emitted light of the light source 11 is located at the center of the aperture 21, that is, the position of the main diffraction light spot in the test light spot is the same as the position of the reference light spot; the diffraction noise light spot generated due to the periodic manufacturing error on the grating and the center offset setting of the aperture 21, that is, the position of the diffraction noise light spot in the test light spot is different from the position of the reference light spot. Therefore, when there is a light spot deviating from the center of the aperture 21 in the test light spot, it can be judged that there is a periodic manufacturing error on the grating.

[0126] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A detection device, characterized in that: include: A light source module, the light source module is used to emit light; An aperture module, the aperture module comprising an aperture, the aperture being movably arranged on the light-emitting side of the light source module; as well as A sample fixing module is arranged between the light source module and the aperture module, and is used for loading the grating to be measured and adjusting the orientation of the grating to be measured relative to the light source module so that the light is transmitted through different points to be measured of the grating to be measured and forms a test light spot on the aperture module.

2. The detection device according to claim 1, characterized in that The aperture module comprises: The diaphragm is provided with an annular slit, and the diaphragm and the grating to be measured are arranged in parallel; and An aperture carrier is connected to the aperture drive and is used to drive the aperture to move relative to the light source module in a direction parallel to the grating to be tested, so that the annular slit and the test light spot are aligned and matched.

3. The detection device according to claim 2, characterized in that: The aperture comprises: A first aperture portion, wherein the first aperture portion is arranged in a circular shape; and A second aperture portion, the second aperture portion is arranged in an annular shape and is arranged around the first aperture portion to form the annular slit together with the first aperture portion; The outer diameter of the first aperture part is adjustable, and the inner diameter of the second aperture part is adjustable, so that the annular slit is aligned with the test light spot.

4. The detection device according to claim 2, characterized in that: The detection device further comprises a detection module, which is arranged on a side of the aperture module away from the light source module. The detection module includes at least two photoelectric detectors, and a plurality of the photoelectric detectors are sequentially spaced apart along the circumference of the annular slit.

5. The detection device according to any one of claims 1 to 4, characterized in that: The light source module comprises a light source and a light source holder, the light source is used to emit light, and the light source holder is drivingly connected to the light source to adjust the emission direction of the light source; And / or, the sample fixing module comprises a sample fixing fixture and a sample carrier, the sample fixing fixture is used to install the grating to be measured, and the sample carrier is drivingly connected to the sample fixing fixture to adjust the orientation of the grating to be measured relative to the light source module; And / or, at least one of the sample fixing module and the aperture module can be movably arranged along the arrangement direction of the sample fixing module and the aperture module.

6. A grating detection method, characterized in that: The grating detection method is applied to the grating detection device according to any one of claims 1 to 5, wherein the grating detection device comprises a light source module, a sample fixing module and an aperture module, and the detection method comprises the following steps: Loading the grating to be measured on the sample fixing module; Turning on the light source module to emit light to different test points of the grating to be tested, so as to obtain a test light spot located on the aperture of the aperture module; It is determined whether the grating to be measured has periodic manufacturing errors according to the position information of the target light spot.

7. The grating detection method according to claim 6, characterized in that: The step of determining whether the grating to be tested has a periodic manufacturing error according to the position of the target light spot further includes: Determining the position information of the reference light spot according to the main light emitted by the light source module; Comparing the position information of the test light spot and the reference light spot; If the position information of the target light spot is the same as the position information of the reference light spot, it is determined that the grating to be tested is normal; If the position information of the target light spot is different from the position information of the reference light spot, it is determined that there is a periodic manufacturing error in the grating to be measured.

8. The grating detection method according to claim 7, characterized in that: After the step of determining that the grating to be measured has periodic manufacturing errors, the method further includes: According to the position information of the target light spot and the reference light spot, the period of the periodic manufacturing error of the grating to be measured is calculated, and the calculation formula is: Wherein, d0 represents the period of the periodic manufacturing error of the grating to be measured, λ0 represents the wavelength of the light of the light source module, a represents the distance between the target light spot and the reference light spot, and D represents the distance between the target light spot and the grating to be measured.

9. The grating detection method according to claim 8, characterized in that: After the step of calculating the period of the periodic manufacturing error of the grating to be measured according to the position information of the target light spot and the reference light spot, the method further includes: Changing the wavelength of light of the light source module, and calculating a plurality of periodic values ​​of the periodic manufacturing error of the grating to be measured corresponding to different light wavelengths; The average value is calculated according to multiple period values ​​of the periodic manufacturing error of the grating to be measured corresponding to different light wavelengths to obtain the period of the periodic manufacturing error of the grating to be measured.

10. The grating detection method according to claim 6, characterized in that: The step of turning on the light source module and emitting light to different test points of the grating to be tested to obtain a test light spot on the aperture of the aperture module also includes: Turning on the light source module; Calibrate the test optical path so that the light emitted by the light source is vertically incident on the surface of the grating to be tested, and the main emitted light of the light source is aligned with the center of the aperture; The grating to be tested is moved to a position to be tested to obtain a test light spot on the aperture of the aperture module.

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