Calibration method and system, defect detection equipment and storage medium

Abstract

The invention relates to the technical field of optical detection, in particular to a calibration method and system, defect detection equipment and a storage medium. According to the invention, the deviation between the light intensity distribution of the light spot formed by the detection light beam and the standard light intensity distribution corresponding to the reference light spot is obtained, and the spatial state of the detection light beam is adjusted in the first direction and the second direction, so that the deviation is eliminated, the light spot is adjusted to be the target light spot, and the adjustment of the detection light beam is realized.

Description

Technical Field

[0001] The present invention relates to the field of optical detection technology, and in particular to a calibration method, system, defect detection equipment and storage medium. Background Art

[0002] The existing method of optical path calibration is generally to allow oblique incident light to be incident on the wafer surface and then fully reflected to a position detector to obtain the position of the inclined light spot, and then to calibrate the optical path by adjusting the height of the wafer surface so that the position of one latitude direction of the oblique incident light spot is calibrated. However, this method has limitations and cannot achieve adjustment of the light spot in two latitudes in the XY directions. Summary of the invention

[0003] In view of this, in order to solve the above technical problems, the purpose of the present invention is to provide a calibration method, system, defect detection equipment and storage medium, which can realize the control and adjustment of the light spot during the detection process.

[0004] In a first aspect, an embodiment of the present invention provides a calibration method, which includes: obtaining light intensity distribution corresponding to a first light spot and a second light spot; based on the deviation of the light intensity distribution from a standard light intensity distribution, adjusting the relative positions of the first light spot and the second light spot in a first direction and a second direction, respectively, until the light intensity distribution corresponding to the first light spot and the second light spot is within the standard light intensity distribution range.

[0005] In some specific implementations, the light intensity distribution includes a first light intensity distribution and a second light intensity distribution, and the standard light intensity distribution includes a first standard light intensity distribution and a second standard light intensity distribution.

[0006] In some specific implementations, the deviation includes a first deviation and a second deviation, wherein the first deviation is used to characterize the deviation between the first light spot and the second light spot in a first direction, and the second deviation is used to characterize the deviation between the first light spot and the second light spot in a second direction.

[0007] In some specific implementations, the light intensity distribution is obtained by using a detector to acquire scattered light signals of the first light spot and the second light spot on the first calibration pattern and the second calibration pattern, respectively.

[0008] In some specific implementations, the first calibration pattern and the second calibration pattern are composed of photolithographic gradient Ronchi lines, and the Ronchi lines in the first calibration pattern have a pitch variation in a first direction, and the Ronchi lines in the second calibration pattern have a pitch variation in a second direction.

[0009] In some specific implementations, the standard light intensity distribution includes a first standard light intensity distribution and a second standard light intensity distribution, which are obtained by respectively acquiring scattered light signals of a reference light spot on a first calibration pattern and a second calibration pattern through a detector.

[0010] In a second aspect, a calibration system is provided, including: an optical element, wherein a first detection beam and a second detection beam form a first light spot and a second light spot after passing through the corresponding optical element respectively; a light intensity acquisition module, used to acquire a first light intensity distribution and a second light intensity distribution corresponding to the first light spot and the second light spot respectively; a processing module, used to determine whether there is a deviation between the first light intensity distribution, the second light intensity distribution and the standard light intensity distribution; and an adjustment module, used to adjust the relative positions of the first light spot and the second light spot in the first direction and the second direction.

[0011] According to a third aspect, a defect detection device is provided, comprising: a light source for generating a first detection beam and a second detection beam; a support platform for placing an object to be detected and a calibration module having the same plane as the object to be detected, the first detection beam and the second detection beam forming a first light spot and a second light spot on the calibration module; and a calibration system as described above.

[0012] In some specific implementations, a first calibration pattern and a second calibration pattern are partitioned on the calibration module, the first calibration pattern and the second calibration pattern are composed of Ronchi lines with photolithography gradients, and the Ronchi lines in the first calibration pattern have a spacing change in a first direction, and the Ronchi lines in the second calibration pattern have a spacing change in a second direction.

[0013] In a fourth aspect, a computer-readable storage medium is provided, wherein a program is stored on the medium, and the program can be executed by a processor to implement any of the methods described above.

[0014] The embodiments of the present invention bring the following beneficial effects: Embodiments of the present invention provide a calibration method, system, defect detection equipment and storage medium. By obtaining the deviation between the light intensity distribution of a light spot formed by a detection light beam and the standard light intensity distribution corresponding to a reference light spot, the spatial state of the detection light beam is adjusted in a first direction and a second direction, thereby eliminating the deviation and adjusting the light spot to a target light spot, thereby achieving adjustment of the detection light beam.

[0015] Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present disclosure.

[0016] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] The methods, systems and / or programs in the accompanying drawings will be further described according to exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein example numbers represent similar mechanisms in the various views of the accompanying drawings.

[0019] Figure 1 A schematic diagram of the structure of the defect detection equipment provided by the present invention; Figure 2 A schematic diagram of the calibration system structure provided by the present invention; Figure 3 A schematic diagram of a calibration module pattern distribution provided by the present invention; Figure 4 A schematic diagram of standard light intensity distribution provided by the present invention; Figure 5 A schematic diagram of the calibration subsystem structure provided by the present invention; Figure 6 A schematic diagram of a first direction calibration process provided by the present invention; Figure 7 A schematic diagram of a second direction calibration process provided by the present invention; Figure 8 A schematic diagram of a calibration method provided by the present invention; Fig. 9 A schematic diagram of the process flow of the method for obtaining the standard light intensity distribution provided by the present invention; Fig.10 A schematic diagram of the structure of the readable medium provided by the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0021] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] The device for detecting wafer defects based on the principle of optical scattering requires oblique lighting. In actual scenarios, the tolerance of the detection beam and strain factors may cause the position of the light spot to deviate on the surface of the wafer to be tested.

[0024] Therefore, before testing, in order to ensure that the tolerance of the detection beam is eliminated, the detection beam needs to be calibrated to avoid deviation of the light spot position on the surface of the wafer to be tested.

[0025] In view of this technical background, the present embodiment provides a calibration method and system, which adjusts the detection beam by acquiring the light intensity distribution of the light spot of the current detection beam and the light intensity distribution of the reference light spot.

[0026] Wherein, for the present embodiment, "wafer" generally refers to a substrate formed of semiconductor or non-semiconductor materials. Examples include (but are not limited to) single crystal silicon, gallium arsenide, gallium nitride, and indium phosphide. Such substrates are typically found and / or processed in semiconductor manufacturing facilities. In some cases, a wafer may include only a substrate (i.e., a bare die). Alternatively, a wafer may include one or more layers of different materials formed on a substrate. One or more layers formed on a wafer may be "patterned" or "unpatterned". For example, a wafer may include multiple dies with repeatable pattern features.

[0027] See also Figure 1 In this embodiment, a defect detection device 10 is first provided. The defect detection device at least includes a light source (not shown), a carrier 11 and a calibration system 12, wherein the carrier is used to place a wafer 20 to be detected, the light source is used to generate a detection beam and project it to the wafer to be detected on the carrier; the calibration system is used to adjust the detection beam so that the light spot formed by the detection beam on the surface of the wafer to be detected meets the preset conditions. The compliance with the preset conditions of the light spot refers to that the light intensity distribution corresponding to the formed light spot meets the preset standard light intensity distribution range.

[0028] In this embodiment, a calibration module 13 having the same plane as the wafer to be detected is also provided on the carrier; the same plane means that the upper plane of the calibration module is flush with the upper plane of the wafer to be detected. The calibration module is a calibration plate, which is used to provide a calibration scene for the calibration process, that is, the light intensity corresponding to the light spot is determined through the calibration pattern on the calibration module.

[0029] Specifically, in this embodiment, the light spot formed by the detection beam on the wafer to be detected is generally an elliptical light spot, which is extended along the first direction 14 and the second direction 15, respectively, and the long side direction of the formed light spot is parallel to the X-axis of the wafer to be detected. Among them, the first direction is the X-axis direction relative to the wafer to be detected, and the second direction is the Y-axis direction relative to the wafer to be detected. Therefore, the calibration of the light spot also includes adjustments in two directions, namely, adjusting the first direction and the second direction of the light spot respectively.

[0030] In this embodiment, the adjustment in the first direction and the adjustment in the second direction refer to moving the formed light spot along the X-axis or along the Y-axis. When performing light spot scanning imaging, the scanning light spot may be defocused or change position due to system errors, changes in the height of the carrier, and different height divisions of the wafer itself, so the light spot needs to be adjusted. The position change includes the position change of the X-axis and the position change of the Y-axis. Therefore, in this embodiment, the light spot needs to be adjusted in two directions to ensure that the light spot is formed on the surface of the wafer to be detected in a stable focal length state.

[0031] Among them, the adjustment of the first direction includes a variety of executable methods. The first method is to adjust the height of the carrier table, and change the height of the carrier table to change the position of the light spot on the wafer to be detected corresponding to the first direction. The second method is to adjust the incident angle of the detection beam, which is achieved by setting an angle-adjustable reflector in the optical path of the detection beam, and adjusting the angle of the reflector to change the position of the light spot on the wafer to be detected corresponding to the first direction; and in this embodiment, the angle change of the reflector is driven by a motor. The third method is a combination of the above two methods, that is, when adjusting the first direction, the height of the carrier table is changed and the incident angle of the detection beam is adjusted.

[0032] It is worth noting that any of the above three methods can achieve the change of the position of the light spot in the first direction, and any method can be selected according to actual conditions.

[0033] As for the adjustment in the second direction, a cylindrical mirror is provided in the optical path of the detection light beam. Specifically, a cylindrical mirror group is provided in the optical path of the detection light beam, and the position adjustment in the second direction is achieved by adjusting the relative position of the cylindrical mirror. This process can be implemented by using an optical component in the prior art, and will not be described in detail in this embodiment.

[0034] In this embodiment, in order to achieve the above-mentioned spot adjustment, a calibration system is provided. For the structure of the calibration system, please refer to Figure 2 The system includes physical devices and virtual devices, wherein the physical device is an optical element 121, the optical element is used to make the detection light beam pass through the calibration module to form a corresponding light spot, and the virtual module is used to process the light spot and realize adjustment.

[0035] Specifically, according to the processing process, the virtual module is divided into a light intensity acquisition module 122, a processing module 123 and an adjustment module 124, wherein the light intensity acquisition module is used to obtain the light intensity distribution corresponding to the light spot, the processing module is used to determine whether there is a deviation between the light intensity distribution and the standard light intensity distribution, and determine the deviation of the relative position between the first direction and the second direction according to the deviation of the light intensity; the adjustment module is used to adjust the relative position of the light spot in the first direction and the second direction to eliminate the deviation.

[0036] In this embodiment, the adjustment module is not a specific execution module. The adjustment module sends commands to the corresponding hardware actuators of the support platform, reflector and cylindrical mirror group to achieve adjustment according to the relative position deviation in the first direction and / or the second direction.

[0037] The first direction and the second direction are adjusted by respectively adjusting the first light intensity distribution of the light spot in the first direction and the second light intensity distribution in the second direction from the first standard light intensity distribution and the second standard light intensity distribution. Therefore, the calibration system in this embodiment needs to obtain the light intensity distribution in the first direction and the second direction respectively through the light intensity acquisition module.

[0038] See also Figure 3 In order to meet the need of obtaining light intensity distribution in two directions, the calibration module 13 in this embodiment has light intensity distribution in the first direction and the second direction respectively, and is configured with at least two calibration areas, namely a first calibration area 131 and a second calibration area 132 .

[0039] The first calibration area and the second calibration area are respectively provided with corresponding calibration patterns, which are used to obtain the light intensity distribution of the light spot in the first direction and the second direction respectively. The calibration patterns include a first calibration pattern and a second calibration pattern composed of Ronchi lines based on photolithography gradient.

[0040] Among them, the Ronchi line has high-precision dimensional tolerance and position tolerance, and the chrome-plated surface has a high reflectivity, such as Figure 3 The black side is the reflective side, and the white side is the transmissive side. The first calibration pattern is used to obtain the light intensity distribution in the first direction, and the second calibration pattern is used to obtain the light intensity distribution in the second direction. The difference between the first calibration pattern and the second calibration pattern is that the distribution of the Ronchi lines is different. The Ronchi lines in the first calibration pattern have a spacing change in the first direction, and the Ronchi lines in the second calibration pattern have a spacing change in the second direction.

[0041] For the variation of the spacing in the second direction in the second calibration pattern, please refer to Figure 3 The change along the angle of 45° with the X-axis or the Y-axis may also include the change directly along the Y-axis in other embodiments. In this embodiment, the change along the angle of 45° with the X-axis or the Y-axis is preferred.

[0042] Wherein, for the first light intensity distribution and the second light intensity distribution, a scattered light signal of a light spot on the first calibration pattern and the second calibration pattern is obtained by providing a detector. This process can be referred to the prior art and will not be described in detail in this embodiment.

[0043] In this embodiment, the first standard light intensity distribution and the second standard light intensity distribution are obtained based on the light intensity expression of the reference light spot on the first calibration pattern and the second calibration pattern. The reference light spot refers to a light spot in the standard position range in the X-axis direction and the Y-axis direction, that is, the first direction and the second direction. It can also be understood that the reference light spot refers to a light spot without defocus or defocus.

[0044] It is worth noting that in the present embodiment, the first light intensity distribution and the second light intensity distribution both conform to the normal distribution curve, while the first standard light intensity distribution and the second standard light intensity distribution are interval light intensity range values.

[0045] Specifically, in this embodiment, the first standard light intensity distribution and the second standard light intensity distribution are standard light intensity peak intervals, which are intervals formed by adjusting the range at the standard light intensity peak.

[0046] The processing module further calculates the peak deviations between the first light intensity distribution and the second light intensity distribution and the first standard light intensity distribution and the second standard light intensity distribution, respectively, and uses the peak deviation as a quantitative indicator of defocus. The larger the deviation value, the more serious the deviation in the first direction and the second direction.

[0047] The adjustment module performs adjustment operations according to the peak deviation value calculated by the processing module. As mentioned above, for the deviation in the first direction, the adjustment module sends an adjustment command to the carrier platform or the optical element, and adjusts the height of the carrier platform or the incident angle of the optical element through the actuator until the deviation is eliminated; for the deviation in the second direction, the adjustment module sends an adjustment command to the cylindrical mirror group, and implements the relative position relationship of the multiple cylindrical mirrors in the cylindrical mirror group through the actuator.

[0048] In this embodiment, the optical element is a reflecting mirror.

[0049] The actuator can be a motor, and the motor has different movement directions according to different movements. For example, for the height movement of the carrier, the vertical movement motor drives the carrier to move; for the movement of the reflector, the actuator is a rotary motor, which drives the reflector to change the angle relative to the detection beam; for the movement of the cylindrical mirror group, the actuator is a linear motor, which is connected to multiple cylindrical mirrors respectively, and drives the cylindrical mirrors to move relative to each other.

[0050] It is worth noting that there are two detection beams in the defect detection device in this embodiment, which are projected onto the surface of the wafer to be detected through two incident light paths, one of which is an oblique incident beam at an angle relative to the wafer to be detected, and the other is a normal incident beam relative to the wafer to be detected. The oblique incident beam and the normal incident beam form a first light spot and a second light spot on the surface of the wafer to be detected, respectively. The formation of the oblique incident beam and the incident angle of the oblique incident beam are achieved by a reflector.

[0051] The calibration of the detection light beam is to calibrate the oblique incident light beam and the normal incident light beam in the first direction and the second direction respectively.

[0052] However, it is worth noting that the reference light spot is the light spot with an overlapping relationship after the above two detection beams are adjusted. Therefore, the acquisition of the reference light spot requires the adjustment of the oblique incident light beam and the normal incident light beam before the calibration. The adjustment of the oblique incident light beam and the normal incident light beam is achieved by collecting the imaging light spots of the above two detection beams, and adjusting the optical elements in the oblique incident light beam and the normal incident light beam respectively according to the difference in the light spot positions of the two.

[0053] It can be understood that the adjustment process is performed before defect detection, and the adjustment and calibration are respectively used to deal with different situations.

[0054] Specifically, the adjustment is used to statically adjust the optical elements in the defect detection system, that is, the adjustment is performed to overcome the tolerance of the optical elements before detection. The adjustment can avoid the unstable spot formation caused by the installation error of the optical elements.

[0055] The calibration is performed during the detection process, because during the detection process, due to the motion error of the carrier and the height change of the wafer itself, the detection beam needs to be calibrated. Therefore, it can be seen that the light spot generated by the oblique incident light beam and the normal incident light beam after adjustment is the optimal light spot when the height of the carrier and the height of the wafer do not change, that is, it is specified as the reference light spot in this embodiment.

[0056] Therefore, in this embodiment, the light spot formed during the detection process is calibrated by taking the light spot that is not dynamically affected during the detection process as the reference light spot.

[0057] In another possible implementation, the reference light spot and the corresponding standard light intensity distribution may be pre-set in the server and may be directly retrieved during the detection process.

[0058] Returning to this embodiment, in order to obtain the imaging spots of the oblique incident light beam and the normal incident light beam, refer to Figure 4 The calibration module is also provided with a third area, which is a diffuse reflection area for the reflection imaging of the oblique incident light beam and the normal incident light beam. A camera is also provided for collecting the reflected light to realize the light spot imaging of the above two detection beams.

[0059] In this embodiment, by irradiating the oblique incident light beam and the normal incident light beam to the diffuse reflection area, the camera performs imaging respectively, and obtains the spot images P1 and P2 of the oblique incident light beam and the normal incident light beam respectively. Then, the pixel centers of P1 and P2 are obtained respectively by the image centroid algorithm, and the center lines of the long side directions of the elliptical light spots of the oblique incident light beam and the normal incident light beam are fitted. Based on the pixel center and the center line in the long side direction, it is judged whether the oblique incident light beam and the normal incident light beam need to be adjusted, and the optical elements on the propagation paths of the oblique incident light beam and the normal incident light beam are adjusted in YX and RZ, so that the pixel centers of P1 and P2 coincide and the center lines of the long side directions of the elliptical light spots coincide, that is, the adjustment of the oblique incident light beam and the normal incident light beam is completed, so that the light spots formed by the above two detection beams coincide to obtain a reference light spot. In addition, the corresponding first reference light spot and second reference light spot are generated for the adjusted oblique incident light beam and the normal incident light beam respectively.

[0060] The image centroid algorithm used may be an algorithm in the prior art, which will not be described in detail in this embodiment.

[0061] Through the above process, a reference light spot in the defect detection device can be obtained, and the first standard light intensity distribution and the second standard light intensity distribution are implemented based on the reference light spot.

[0062] Specifically, the first standard light intensity distribution and the second standard light intensity distribution are obtained by projecting the adjusted reference light spot onto the first calibration pattern and the second calibration pattern. The first reference light spot and the second reference light spot are generated on the first calibration pattern by projecting the adjusted oblique incident light beam and the normal incident light beam onto the first calibration pattern respectively.

[0063] The light intensity information of the first reference light spot and the second reference light spot is obtained by the detector, and the average value of the light intensity peak values ​​of the first reference light spot and the second reference light spot is used as the reference light intensity distribution, and the reference light intensity distribution is adjusted within a preset adjustment range to obtain the first standard light intensity distribution. Similarly, for the determination of the second standard light intensity distribution, the average value of the light intensity peak values ​​of the first reference light spot and the second reference light spot on the second calibration pattern is used as the reference light intensity distribution, and the reference light intensity distribution is adjusted within a preset adjustment range to obtain the second standard light intensity distribution.

[0064] For a schematic diagram of the first standard light intensity distribution and the second standard light intensity distribution in this embodiment, please refer to Figure 5In this embodiment, the first standard light intensity distribution and the second standard light intensity distribution are not complete normal distributions, and the average value of the light intensity peak value 51 of the first reference light spot and the second reference light spot is used and the adjustment range is increased to form an interval light intensity range 52. The light spot is calibrated by the interval limitation method, which reduces the time cost and difficulty of calibration, and realizes fast calibration on the basis of meeting the calibration accuracy.

[0065] For a description of the calibration process for the first orientation of the system, please visit Figure 6 , based on the oblique incident light beam and the normal incident light beam, a first light spot 61 and a second light spot 62 are formed on the first calibration pattern respectively. The calibration module is driven to rotate by the carrier, and the first calibration pattern in the calibration module is scanned in a circular form based on the first light spot, and the first light intensity distribution 63 corresponding to the first light spot is obtained; similarly, the first calibration pattern is scanned in a circular form by the second light spot, and the second light intensity distribution 64 corresponding to the second light spot is obtained. The first light intensity distribution and the second light intensity distribution are matched with the standard light intensity distribution 52 to determine whether the peak values ​​of the first light intensity distribution and the second light intensity distribution are between the standard light intensity distribution 52. When the peak value of any light intensity distribution is not within the standard light intensity distribution interval, it is adjusted until the peak value of the light intensity distribution is within the interval.

[0066] Based on the deviation between the standard light intensity distribution and the first light intensity distribution and the second light intensity distribution, the height of the carrier is adjusted through the adjustment module, or the reflector in the oblique incident light beam is adjusted through the adjustment module.

[0067] Please continue reading Figure 6 The second light intensity distribution meets the standard light intensity distribution interval, and the first light intensity distribution does not meet the standard light intensity distribution interval; the reflector in the oblique incident light beam is adjusted by the adjustment module to make the first light intensity distribution meet the standard light intensity distribution interval.

[0068] See also Figure 7 , a description of the process of calibrating the calibration system in the second direction. Similarly, the first light intensity distribution and the second light intensity distribution of the first light spot and the second light spot on the second calibration pattern are obtained, the first light intensity distribution and the second light intensity distribution are matched with the standard light intensity distribution, and the lens group in the oblique incident light beam and the normal incident light beam is adjusted in the second direction through the adjustment module based on the deviation between the standard light intensity distribution and the first light intensity distribution and the second light intensity distribution.

[0069] See also Figure 8 , the specific process of the spot calibration method of the calibration system is described below, including the following steps: Step S81: Obtain the light intensity distribution corresponding to the first light spot and the second light spot.

[0070] Step S82: Based on the deviation between the light intensity distribution and the standard light intensity distribution, the relative positions of the first light spot and the second light spot in the first direction and the second direction are adjusted respectively until the light intensity distributions corresponding to the first light spot and the second light spot are within the standard light intensity distribution range.

[0071] See also Fig. 9 This embodiment also provides a method for determining a standard light intensity distribution. The method comprises the following steps: Step S91: Acquire the first light spot image and the second light spot image and the corresponding pixel centers, and obtain the long side direction center lines corresponding to the first light spot and the second light spot through linear fitting.

[0072] Step S92: Based on the relative positional relationship between the pixel center and the center line in the long side direction, adjust the first light spot and the second light spot until the pixel centers of the first light spot and the center lines in the long side direction coincide with each other, thereby obtaining a reference light spot.

[0073] Step S93: Obtain corresponding light intensity distributions on the first calibration pattern and the second calibration pattern respectively through the reference light spot.

[0074] Step S94. The average value of the peak value of the light intensity distribution is used as the reference light intensity, and the reference light intensity is adjusted within a preset adjustment range to obtain a standard light intensity distribution.

[0075] In this embodiment, the first light spot image and the second light spot image are collected through a diffuse reflection plate.

[0076] See also Fig.10 An embodiment of the present invention provides a readable medium 10, which stores computer-readable instructions 101. The computer-readable instructions 101 include instructions for executing the aforementioned calibration method and standard light intensity distribution determination method.

[0077] The functions and technical effects of the readable medium 10 provided in the embodiment of the present invention may refer to the technical effects of the calibration method in the aforementioned embodiment, and will not be described in detail here.

[0078] It should be noted that in the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and / or methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units / modules is only a logical function division. There may be other division methods in actual implementation, such as multiple units or modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0079] The units / modules described as separate components may or may not be physically separated, and the components shown as units / modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units / modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0080] In addition, each functional unit / module in each embodiment of the present invention may be integrated into one processing unit / module, or each unit / module may exist physically separately, or two or more units / modules may be integrated into one unit / module. The above-mentioned integrated unit / module may be implemented in the form of hardware or in the form of hardware plus software functional units / modules.

[0081] The above-mentioned integrated unit / module implemented in the form of a software functional unit / module can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for causing one or more processors of a computer device (which can be a personal computer, a server, or a network device, etc.) to perform some steps of the method described in each embodiment of the present invention.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calibration method, characterized in that: The method comprises: Acquire the light intensity distribution corresponding to the first light spot and the second light spot; Based on the deviation between the light intensity distribution and the standard light intensity distribution, the relative positions of the first light spot and the second light spot in the first direction and the second direction are adjusted respectively until the light intensity distributions corresponding to the first light spot and the second light spot are within the standard light intensity distribution range.

2. The calibration method according to claim 1, characterized in that: The light intensity distribution includes a first light intensity distribution and a second light intensity distribution, and the standard light intensity distribution includes a first standard light intensity distribution and a second standard light intensity distribution.

3. The calibration method according to claim 2, characterized in that: The deviation includes a first deviation and a second deviation, wherein the first deviation is used to characterize the deviation of the first light spot and the second light spot in a first direction, and the second deviation is used to characterize the deviation of the first light spot and the second light spot in a second direction.

4. The calibration method according to claim 1, characterized in that: The light intensity distribution is obtained by acquiring scattered light signals of the first light spot and the second light spot on the first calibration pattern and the second calibration pattern respectively through a detector.

5. The calibration method according to claim 4, characterized in that: The first calibration pattern and the second calibration pattern are composed of Ronchi lines with gradual photolithography, and the Ronchi lines in the first calibration pattern have a pitch variation in a first direction, and the Ronchi lines in the second calibration pattern have a pitch variation in a second direction.

6. The calibration method according to claim 4, characterized in that: The standard light intensity distribution includes a first standard light intensity distribution and a second standard light intensity distribution, which are obtained by respectively acquiring scattered light signals of a reference light spot on a first calibration pattern and a second calibration pattern through a detector.

7. A calibration system, characterized in that: include: An optical element, wherein the first detection light beam and the second detection light beam form a first light spot and a second light spot after passing through the corresponding optical element respectively; A light intensity acquisition module, used to acquire a first light intensity distribution and a second light intensity distribution corresponding to the first light spot and the second light spot respectively; A processing module, used for determining whether there is a deviation between the first light intensity distribution, the second light intensity distribution and a standard light intensity distribution; The adjustment module is used to adjust the relative positions of the first light spot and the second light spot in the first direction and the second direction.

8. A defect detection device, characterized in that: include: a light source, for generating a first detection light beam and a second detection light beam; A carrier platform, used for placing an object to be detected and a calibration module having the same plane as the object to be detected, and the first detection beam and the second detection beam form a first light spot and a second light spot on the calibration module; A calibration system as claimed in claim 7.

9. The defect detection device according to claim 8, characterized in that: The calibration module is partitioned with a first calibration pattern and a second calibration pattern, wherein the first calibration pattern and the second calibration pattern are composed of Ronchi lines with gradual photolithography, and the Ronchi lines in the first calibration pattern have a spacing change in a first direction, and the Ronchi lines in the second calibration pattern have a spacing change in a second direction.

10. A computer-readable storage medium, characterized in that: The medium stores a program, which can be executed by a processor to implement the method according to any one of claims 1 to 6.

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