Adjustment method of detection equipment

Abstract

The invention provides an adjustment method of detection equipment, and the detection equipment sequentially comprises an objective lens, a spectroscope, a barrel lens and a detector from an object space to an image space, and also comprises a Kohler illumination module. The illumination light beam is emitted from the Kohler illumination module and is transmitted to the objective lens through the spectroscope, when the object to be detected is arranged on one side, far away from the spectroscope, of the objective lens, the illumination light beam emitted from the objective lens is reflected to obtain a reflected light beam, and the reflected light beam sequentially passes through the objective lens, the spectroscope and the barrel lens to reach the detector. After an aperture diaphragm is inserted into the Kohler illumination module and an auxiliary lens is arranged between the barrel lens and the detector, obtaining a first light spot position of a light spot formed by the aperture diaphragm at an entrance pupil of the objective lens through the detector; and under the condition that the Kohler illumination module does not provide the illumination light beam and the light source is used as an object to be detected, acquiring a second light spot position of the light spot of the entrance pupil of the objective lens through the detector, adjusting the position of the aperture diaphragm according to the first light spot position and the second light spot position, and aligning the illumination optical axis and the imaging optical axis.

Description

Technical Field

[0001] The present application relates to the field of microscopic imaging, and in particular to an adjustment method for a detection device. Background Art

[0002] In the semiconductor manufacturing process, it is often necessary to use detection equipment to detect the object to be tested, such as the wafer to be tested. The detection equipment usually includes a Kohler illumination module to illuminate the imaging system. In order to obtain better imaging effects, the optical axes of the Kohler illumination module and the imaging system need to be aligned. In the process of detecting the object to be tested, the aperture diaphragm needs to be switched in the Kohler illumination module. Different aperture diaphragms have different sizes, thereby producing different illumination numerical apertures (NA). In response to the measurement of different objects to be tested, during the switching of the aperture diaphragm, it is necessary to ensure that the optical axis of the inserted aperture diaphragm is aligned with the original optical axis, so that the illumination optical axis passing through the aperture diaphragm is aligned with the imaging optical axis. The current alignment method is inefficient and complicated to operate. Summary of the invention

[0003] In view of this, the purpose of this application is to provide an adjustment method for a detection device, which can quickly align the illumination optical axis with the imaging optical axis and is easy to operate. The specific scheme is as follows:

[0004] On the one hand, the present application provides an adjustment method for a detection device, wherein the detection device includes an objective lens, a beam splitter, a tube lens and a detector in sequence from the object side to the image side, and also includes a Kohler illumination module; an illumination light beam is emitted from the Kohler illumination module, and is transmitted to the objective lens through the beam splitter, and when the object to be detected is set on a side of the objective lens away from the beam splitter, the method is used to reflect the illumination light beam emitted from the objective lens to obtain a reflected light beam, and the reflected light beam passes through the objective lens, the beam splitter and the tube lens in sequence to reach the detector; the method includes:

[0005] After inserting an aperture stop into the Kohler illumination module and arranging an auxiliary lens between the tube lens and the detector, the first spot position of the spot formed by the aperture stop in the entrance pupil of the objective lens is acquired through the detector; the auxiliary lens makes the entrance pupil and the image plane of the detector conjugate;

[0006] When the Kohler illumination module does not provide an illumination beam and the surface light source is used as the object to be measured, a second spot position of a spot of an entrance pupil of the objective lens is acquired by the detector;

[0007] The position of the aperture stop is adjusted according to the first light spot position and the second light spot position, so that the light spot centers of the first light spot position and the second light spot position tend to overlap.

[0008] Optionally, adjusting the position of the aperture stop according to the first light spot position and the second light spot position includes:

[0009] Acquire a spot center offset parameter of the first spot position relative to the second spot position;

[0010] The position of the aperture stop is adjusted in a direction perpendicular to the optical axis according to the light spot center offset parameter.

[0011] Optionally, the first light spot position is determined by a first light spot image generated by the detector, and the second light spot position is determined by a second light spot image generated by the detector.

[0012] Optionally, the acquiring a spot center offset parameter of the first spot position relative to the second spot position includes:

[0013] Determine a first light spot position according to a first pixel position of a light spot center in the first light spot image;

[0014] Determine the second light spot position according to the second pixel position of the light spot center in the second light spot image;

[0015] A spot center offset parameter of the first light spot position relative to the second light spot position is determined according to the magnification of the detector and a pixel offset parameter between the first light spot position and the second light spot position.

[0016] Optionally, the detection device further includes an optical fiber for guiding the illumination light beam to the Kohler illumination module, and the method further includes:

[0017] The illumination beam in the optical fiber is removed, or the optical fiber is removed to cancel the illumination beam entering the Kohler illumination module.

[0018] Optionally, the method further includes:

[0019] The auxiliary lens is removed, the illumination beam entering the Kohler illumination module is restored, the object to be tested is arranged on a side of the objective lens away from the beam splitter, and the reflected beam from the object to be tested is detected by the detector to achieve detection of the object to be tested.

[0020] Optionally, the surface to be measured of the object to be measured is arranged on the focal plane of the objective lens, and the focal plane is conjugate with the image plane of the detector.

[0021] Optionally, the auxiliary lens is a focusing lens.

[0022] Optionally, the focal length of the auxiliary lens is 45 mm, the distance between the auxiliary lens and the image plane of the detector is 60.07 mm, the distance between the auxiliary lens and the tube lens is 43.98 mm, the distance between the tube lens and the image plane of the detector is 109.04 mm, the focal length of the objective lens is 2 mm, and the focal length of the tube lens is 200 mm.

[0023] Optionally, the Kohler illumination module includes a first lens, a second lens, and a third lens arranged in sequence, the illumination light beam is converted into parallel light through the first lens, the aperture stop is located between the second lens and the third lens and at the focus of the second lens, the second lens and the third lens are focusing lenses, and the third lens is used to focus the illumination light beam on the entrance pupil of the objective lens in combination with the beam splitter.

[0024] An embodiment of the present application provides an adjustment method for a detection device, wherein the detection device includes an objective lens, a beam splitter, a tube lens and a detector in sequence from the object side to the image side, and also includes a Kohler illumination module; an illumination light beam is emitted from the Kohler illumination module, and is transmitted to the objective lens through the beam splitter. When the object to be measured is arranged on a side of the objective lens away from the beam splitter, the method is used to reflect the illumination light beam emitted from the objective lens to obtain a reflected light beam, and the reflected light beam passes through the objective lens, the beam splitter and the tube lens in sequence to reach the detector. After inserting an aperture stop in the Kohler illumination module and setting an auxiliary lens between the tube lens and the detector, the first spot position of the spot formed by the aperture stop in the entrance pupil of the objective lens is obtained through the detector; the auxiliary lens makes the entrance pupil and the image plane of the detector conjugate, and since the aperture stop and the entrance pupil of the objective lens are conjugate, the aperture stop and the image plane of the detector are also conjugate, and the spot position of the aperture stop can be obtained through the detector; when the Kohler illumination module does not provide an illumination beam and the light source is used as the object to be measured, the second spot position of the spot of the entrance pupil of the objective lens is obtained through the detector; the first spot position can also reflect the spot position of the aperture stop in the entrance pupil of the objective lens, and the second spot position reflects the spot position of the entrance pupil itself, so the relative position of the two reflects the relative position of the illumination optical axis and the imaging optical axis, and the position of the aperture stop is adjusted according to the first spot position and the second spot position, so that the spot centers of the first spot position and the second spot position tend to overlap, so that the operation is targeted, the illumination optical axis and the imaging optical axis can be quickly aligned, and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application 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 some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram of the structure of a detection device provided in an embodiment of the present application is shown;

[0027] Figure 2 A schematic diagram showing a flow chart of an adjustment method of a detection device provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of an imaging process provided by an embodiment of the present application is shown;

[0029] Figure 4 Another schematic diagram of an imaging process provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0032] Secondly, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0033] As described in the background technology, during the switching process of the aperture stop, it is necessary to ensure that the optical axis of the inserted aperture stop is aligned with the original optical axis, so that the illumination optical axis passing through the aperture stop is aligned with the imaging optical axis. Currently, the laser can be input from the Kohler illumination module by using the laser triangulation method. After passing through the Kohler illumination module, the laser is incident on the objective lens. By setting a reflector on the focal plane of the objective lens, the laser returns to the objective lens through the reflector and is imaged on the camera after passing through the tube lens. By defocusing the reflector, the center change of the light spot on the camera is observed, and then the position of the aperture stop is adjusted to adjust the eccentricity problem of illumination and imaging. However, this method is inefficient and complicated to operate.

[0034] Based on the above technical problems, an embodiment of the present application provides an adjustment method for a detection device, wherein the detection device includes an objective lens, a beam splitter, a tube lens and a detector from the object side to the image side, and also includes a Kohler illumination module; an illumination light beam is emitted from the Kohler illumination module, and is transmitted to the objective lens through the beam splitter. When the object to be measured is set on the side of the objective lens away from the beam splitter, the method is used to reflect the illumination light beam emitted from the objective lens to obtain a reflected light beam, and the reflected light beam passes through the objective lens, the beam splitter and the tube lens in sequence to reach the detector. After inserting an aperture stop in the Kohler illumination module and setting an auxiliary lens between the tube lens and the detector, the first spot position of the spot formed by the aperture stop in the entrance pupil of the objective lens is obtained through the detector; the auxiliary lens makes the entrance pupil and the image plane of the detector conjugate, and since the aperture stop and the entrance pupil of the objective lens are conjugate, the aperture stop and the image plane of the detector are also conjugate, and the spot position of the aperture stop can be obtained through the detector; when the Kohler illumination module does not provide an illumination beam and the light source is used as the object to be measured, the second spot position of the spot of the entrance pupil of the objective lens is obtained through the detector; the first spot position can also reflect the spot position of the aperture stop in the entrance pupil of the objective lens, and the second spot position reflects the spot position of the entrance pupil itself, so the relative position of the two reflects the relative position of the illumination optical axis and the imaging optical axis, and the position of the aperture stop is adjusted according to the first spot position and the second spot position, so that the spot centers of the first spot position and the second spot position tend to overlap, so that the operation is targeted, the illumination optical axis and the imaging optical axis can be quickly aligned, and the operation is simple.

[0035] For ease of understanding, an adjustment method for a detection device provided in an embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0036] refer to Figure 1 As shown, it is a schematic diagram of the structure of a detection device provided in an embodiment of the present application. The detection device includes an objective lens 11, a beam splitter 12, a tube lens 13 and a detector 14 from the image side to the object side, and also includes a Kohler illumination module 15.

[0037] The Kohler illumination module 15 is used to provide uniform and sufficiently bright illumination. The Kohler illumination module 15 may include a first lens 151, a second lens 152, and a third lens 153 arranged in sequence. The illumination beam irradiated into the Kohler illumination module 15 is converted into parallel light by the first lens 151. The second lens 152 and the third lens 153 are focusing lenses. The parallel light passes through the second lens 152 and is focused to the focal position of the second lens 152 to form divergent light incident on the third lens 153. The third lens 153 focuses the divergent light to obtain a focused beam incident on the beam splitter 12 to illuminate the imaging system. In other words, the illumination beam is emitted from the Kohler illumination module 15 to illuminate the imaging system. The illumination beam may be visible light, such as white light.

[0038] The detection device may further include an optical fiber 16 for directing the illumination beam to the Kohler illumination module 15 . The light output port of the optical fiber 16 may be located at the focal position of the first lens 151 , so that the first lens 151 may convert the illumination beam into parallel light.

[0039] The imaging system may include an objective lens 11, a beam splitter 12, a tube lens 13 and a detector 14. After the illumination beam passes through the beam splitter 12, it can be transmitted to the objective lens 11 after being reflected by the beam splitter 12. When the object 20 to be measured is arranged on the side of the objective lens 11 away from the beam splitter 12, the illumination beam emitted from the objective lens 11 can be reflected to obtain a reflected beam. The reflected beam can reflect the morphology of the object 20 to be measured. Then the reflected beam passes through the objective lens 11, the beam splitter 12 and the tube lens 13 in sequence to reach the detector 14. The detector 14 captures the reflected beam to achieve detection of the object 20 to be measured. The tube lens 13 is used to cooperate with the objective lens 11 to image the object 20 to be measured on the focal plane of the objective lens 11. The third lens 153 can focus the illumination beam on the entrance pupil 111 of the objective lens 11 in combination with the beam splitter 12. In this way, the illumination beam is diverged through the objective lens 11, and the surface to be measured of the object 20 to be measured can be evenly illuminated by the illumination beam.

[0040] When the object to be tested 20 is tested, the test surface of the object to be tested 20 can be located on the focal plane of the objective lens 11, and the focal plane of the objective lens 11 is conjugate with the image plane 141 of the detector 14, so as to obtain a clear image of the test surface. As an example, the focal length of the objective lens 11 can be 2 mm, the focal length of the tube lens 13 can be 200 mm, and the distance between the tube lens 13 and the image plane 141 of the detector 14 can be 109.04 mm, so as to realize the detection of the object to be tested 20 based on the detection device.

[0041] refer to Figure 2 FIG. 1 is a flow chart of a method for adjusting a detection device provided in an embodiment of the present application. The method may include the following steps:

[0042] S101, after inserting the aperture stop 17 into the Kohler illumination module 15 and setting the auxiliary lens 18 between the tube lens 13 and the detector 14, the first spot position of the spot formed by the aperture stop 17 at the entrance pupil 111 of the objective lens 11 is obtained through the detector 14; the auxiliary lens 18 makes the entrance pupil 111 and the image plane 141 of the detector 14 conjugate.

[0043] In an embodiment of the present application, an aperture diaphragm 17 can be inserted into the Kohler illumination module 15. The aperture diaphragm 17 is used to limit the imaging light beam. Different illumination numerical apertures can be generated by the aperture diaphragm 17 to cope with the measurement of different objects to be measured 20. The aperture diaphragm 17 can have a single pore or a pore array formed by multiple pores, and the shape of the pore is a circular hole or a rectangular hole.

[0044] Since the pupil plane of the illumination system in the Kohler illumination module 15 is conjugate with the focal plane of the objective lens 11, when the aperture stop 17 is set on the pupil plane of the illumination system, the camera will observe the shape of the aperture stop 17. Specifically, the aperture stop 17 can be located between the second lens 152 and the third lens 153, and at the focus of the second lens 152. The plane perpendicular to the optical axis where the focus of the second lens 152 is located is the focal plane, which serves as the pupil plane of the Kohler illumination module 15.

[0045] Since the aperture stop 17 of the Kohler illumination is conjugate with the entrance pupil 111 of the objective lens 11, the position of the aperture stop 17 can be determined by whether the center of the light spot of the aperture stop 17 at the entrance pupil 111 of the objective lens 11 is aligned with the center of the entrance pupil 111 to determine whether the position of the aperture stop 17 is accurate, that is, whether the optical axis of the aperture stop 17 is aligned with the optical axis of the imaging system. However, since the image plane 141 of the detector 14 is conjugate with the mirror surface of the objective lens 11, the entrance pupil 111 of the objective lens 11 cannot be imaged by relying solely on the tube lens 13.

[0046] Therefore, an auxiliary lens 18 can be arranged between the tube lens 13 and the detector 14. The auxiliary lens 18 makes the entrance pupil 111 of the objective lens 11 and the image plane 141 of the detector 14 conjugate, so that the entrance pupil 111 of the objective lens 11 can be observed. The auxiliary lens 18 is a focusing lens, which can be a double cemented lens. The entrance pupil 111 of the objective lens 11 is a plane perpendicular to the optical axis, which can also be called an entrance pupil plane. The parameters of the auxiliary lens 18 can be obtained according to simulation. As an example, the focal length of the auxiliary lens 18 is 45 mm, the distance between the auxiliary lens 18 and the image plane 141 of the detector 14 is 60.07 mm, and the distance between the auxiliary lens 18 and the tube lens 13 is 43.98 mm.

[0047] In this way, after the aperture stop 17 is inserted into the Kohler illumination module 15 and the auxiliary lens 18 is arranged between the tube lens 13 and the detector 14, the first spot position of the spot formed by the aperture stop 17 at the entrance pupil 111 of the objective lens 11 is obtained through the detector 14, referring to Figure 3 As shown, it is a schematic diagram of an imaging process provided by an embodiment of the present application. The illumination light beam emitted by the Kohler illumination module 15 is focused to the entrance pupil 111 of the objective lens 11 to form a light spot, and the detector 14 detects the light spot to obtain a first light spot position.

[0048] Among them, the first light spot position can be determined by the first light spot image generated by the detector. The first light spot image can include the light spot formed by the aperture diaphragm 17 in the entrance pupil 111 of the objective lens 11. The first light spot position can be determined according to the first pixel position of the light spot center in the first light spot image. The first pixel position is, for example, the pixel position of the pixel center point where the light spot center is located, or the pixel position of the light spot center. For example, the first pixel position can be used as the first light spot position.

[0049] S102 , when the Kohler illumination module 15 does not provide an illumination beam and the surface light source 19 serves as the object to be measured 20 , a second spot position of the spot of the entrance pupil 111 of the objective lens 11 is acquired by the detector 14 .

[0050] When the Kohler illumination module 15 does not provide an illumination beam and the auxiliary lens 18 is retained, it is equivalent to removing the light spot of the aperture diaphragm 17 at the entrance pupil 111 of the objective lens 11. At this time, the light spot of the entrance pupil 111 can be imaged. When the surface light source 19 is used as the object to be measured, the second light spot position of the light spot of the entrance pupil 111 of the objective lens 11 can be obtained by the detector 14. Figure 4 As shown, it is a schematic diagram of another imaging process provided in an embodiment of the present application. The parallel light provided by the surface light source 19 is focused to the entrance pupil 111 of the objective lens 11 under the action of the objective lens 11 to form a light spot, and the detector 14 detects the light spot to obtain a second light spot position.

[0051] Among them, the second light spot position can be determined by a second light spot image generated by the detector. The second light spot image can include the light spot of the entrance pupil 111 of the objective lens 11. The second light spot position can be determined according to the second pixel position of the light spot center in the second light spot image. The second pixel position is, for example, the pixel position of the pixel center point where the light spot center is located, or the pixel position of the light spot center. For example, the second pixel position can be used as the second light spot position.

[0052] In specific implementation, the illumination beam in the optical fiber 16 can be removed, or the illumination beam entering the Kohler illumination module 15 can be removed by removing the optical fiber 16, so that the Kohler illumination module 15 does not provide an illumination beam. The surface light source can be arranged at the focal plane of the objective lens 11.

[0053] S103, adjusting the position of the aperture stop 17 according to the first light spot position and the second light spot position, so that the light spot centers of the first light spot position and the second light spot position tend to overlap.

[0054] According to the above description, the entrance pupil 111 of the objective lens 11 can be illuminated by the illumination beam emitted by the Kohler illumination module 15, and the illuminated entrance pupil 111 is imaged on the detector 14 to obtain the light spot of the Kohler illumination on the entrance pupil 111 of the objective lens 11 to obtain the first light spot position; then, a surface light source is placed on the side of the objective lens 11 away from the detector 14, so that the entrance pupil 111 of the objective lens 11 is illuminated by the surface light source, and the illuminated entrance pupil 111 is imaged on the detector 14 to obtain the light spot of the entrance pupil 111 of the objective lens 11 to obtain the second light spot position. The first light spot position indicates the optical axis position of the aperture stop 17, and the second light spot position indicates the optical axis position of the imaging system. The position of the aperture stop 17 can be adjusted according to the first light spot position and the second light spot position, so that the light spot centers of the first light spot position and the second light spot position tend to overlap, and then the optical axis of the aperture stop 17 is aligned with the optical axis of the imaging system, so that the optical axis alignment of the illumination system and the imaging system is achieved, which is faster and simpler to operate.

[0055] Specifically, a spot center offset parameter of the first spot position relative to the second spot position may be obtained, and according to the spot center offset parameter, the position of the aperture stop 17 is adjusted in a direction perpendicular to the optical axis, so that the optical axis of the aperture stop 17 is aligned with the optical axis of the imaging system. After the first spot position and the second spot position are determined, the spot center offset parameter of the first spot position relative to the second spot position may be determined according to the magnification of the detector 14 and the pixel offset parameter between the first spot position and the second spot position. Generally speaking, the spot center offset parameter is equal to the ratio of the pixel offset parameter and the magnification.

[0056] The pixel shift parameter may be the product of the length of a single pixel and an integer. For example, if the first spot position and the second spot position are offset by 1 pixel, assuming that the pixel length of each pixel is 3.5 microns, the pixel shift parameter is 3.5 microns, and the ratio of the pixel shift parameter divided by the magnification is used as the spot center shift parameter.

[0057] After adjusting the aperture diaphragm 17, the auxiliary lens 18 can be removed to restore the illumination light beam entering the Kohler illumination module 15, and the object to be tested 20 is set on the side of the objective lens 11 away from the beam splitter 12. The reflected light beam from the object to be tested 20 is detected by the detector 14 to realize the detection of the object to be tested 20. The object to be tested 20 can be a wafer to be tested.

[0058] An embodiment of the present application provides an adjustment method for a detection device, wherein the detection device includes an objective lens, a beam splitter, a tube lens and a detector in sequence from the object side to the image side, and also includes a Kohler illumination module; an illumination light beam is emitted from the Kohler illumination module, and is transmitted to the objective lens through the beam splitter. When the object to be measured is arranged on a side of the objective lens away from the beam splitter, the method is used to reflect the illumination light beam emitted from the objective lens to obtain a reflected light beam, and the reflected light beam passes through the objective lens, the beam splitter and the tube lens in sequence to reach the detector. After inserting an aperture stop in the Kohler illumination module and setting an auxiliary lens between the tube lens and the detector, the first spot position of the spot formed by the aperture stop in the entrance pupil of the objective lens is obtained through the detector; the auxiliary lens makes the entrance pupil and the image plane of the detector conjugate, and since the aperture stop and the entrance pupil of the objective lens are conjugate, the aperture stop and the image plane of the detector are also conjugate, and the spot position of the aperture stop can be obtained through the detector; when the Kohler illumination module does not provide an illumination beam and the light source is used as the object to be measured, the second spot position of the spot of the entrance pupil of the objective lens is obtained through the detector; the first spot position can also reflect the spot position of the aperture stop in the entrance pupil of the objective lens, and the second spot position reflects the spot position of the entrance pupil itself, so the relative position of the two reflects the relative position of the illumination optical axis and the imaging optical axis, and the position of the aperture stop is adjusted according to the first spot position and the second spot position, so that the spot centers of the first spot position and the second spot position tend to overlap, so that the operation is targeted, the illumination optical axis and the imaging optical axis can be quickly aligned, and the operation is simple.

[0059] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A method for adjusting a detection device, characterized in that: The detection device includes an objective lens, a beam splitter, a tube lens and a detector in order from the object side to the image side, and also includes a Kohler illumination module; an illumination beam is emitted from the Kohler illumination module, and is transmitted to the objective lens through the beam splitter. When the object to be detected is set on the side of the objective lens away from the beam splitter, the device is used to reflect the illumination beam emitted from the objective lens to obtain a reflected beam, and the reflected beam passes through the objective lens, the beam splitter and the tube lens in order to reach the detector; the method includes: After inserting an aperture stop into the Kohler illumination module and arranging an auxiliary lens between the tube lens and the detector, the first spot position of the spot formed by the aperture stop in the entrance pupil of the objective lens is acquired through the detector; the auxiliary lens makes the entrance pupil and the image plane of the detector conjugate; When the Kohler illumination module does not provide an illumination beam and the surface light source is used as the object to be measured, a second spot position of a spot of an entrance pupil of the objective lens is acquired by the detector; The position of the aperture stop is adjusted according to the first light spot position and the second light spot position, so that the light spot centers of the first light spot position and the second light spot position tend to overlap.

2. The method according to claim 1, characterized in that The adjusting the position of the aperture stop according to the first light spot position and the second light spot position comprises: Acquire a spot center offset parameter of the first spot position relative to the second spot position; The position of the aperture stop is adjusted in a direction perpendicular to the optical axis according to the light spot center offset parameter.

3. The method according to claim 2, characterized in that The first light spot position is determined by a first light spot image generated by the detector, and the second light spot position is determined by a second light spot image generated by the detector.

4. The method according to claim 3, characterized in that The obtaining of the spot center offset parameter of the first spot position relative to the second spot position includes: Determine a first light spot position according to a first pixel position of a light spot center in the first light spot image; Determine the second light spot position according to the second pixel position of the light spot center in the second light spot image; A spot center offset parameter of the first light spot position relative to the second light spot position is determined according to the magnification of the detector and a pixel offset parameter between the first light spot position and the second light spot position.

5. The method according to claim 1, characterized in that The detection device further includes an optical fiber for directing the illumination beam to the Kohler illumination module, and the method further includes: The illumination beam in the optical fiber is removed, or the optical fiber is removed to cancel the illumination beam entering the Kohler illumination module.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: The auxiliary lens is removed, the illumination beam entering the Kohler illumination module is restored, the object to be tested is arranged on a side of the objective lens away from the beam splitter, and the reflected beam from the object to be tested is detected by the detector to achieve detection of the object to be tested.

7. The method according to claim 6, characterized in that The surface to be measured of the object to be measured is arranged on the focal plane of the objective lens, and the focal plane is conjugate with the image plane of the detector.

8. The method according to any one of claims 1 to 5, characterized in that: The auxiliary lens is a focusing lens.

9. The method according to claim 8, characterized in that The focal length of the auxiliary lens is 45 mm, the distance between the auxiliary lens and the image plane of the detector is 60.07 mm, the distance between the auxiliary lens and the tube lens is 43.98 mm, the distance between the tube lens and the image plane of the detector is 109.04 mm, the focal length of the objective lens is 2 mm, and the focal length of the tube lens is 200 mm.

10. The method according to any one of claims 1 to 5, characterized in that: The Kohler illumination module comprises a first lens, a second lens and a third lens arranged in sequence, the illumination light beam is converted into parallel light by the first lens, the aperture stop is located between the second lens and the third lens and at the focus of the second lens, the second lens and the third lens are focusing lenses, and the third lens is used to focus the illumination light beam on the entrance pupil of the objective lens in combination with the beam splitter.

Images