CN217766036U - Optical detection system - Google Patents

Abstract

The application relates to an optical detection system, which mainly comprises a detection table, an illumination assembly, an objective assembly, an image sensor and a linear moving assembly, wherein the linear moving assembly is used for adjusting the moving position of the objective assembly in a preset linear direction, the moving position of the objective assembly is used for changing the offset distance of detection light, and an optical image can be aligned to a preset standard image through correcting the detection light. The technical scheme utilizes the linear moving assembly to adjust the offset distance of the objective lens assembly, so that the displacement compensation can be carried out on the optical image, and the problem of relative displacement of the optical image can be solved by means of physical correction. According to the technical scheme, due to the fact that displacement compensation of image features is conducted in the aspect of physical optics, accurate alignment of the same image features can be achieved, so that the influence of structural deformation of the detection table is eliminated, and the sensitivity of the system for detecting the abnormal area on the surface of the piece to be detected is improved.

Description

Optical detection system

Technical Field

The application relates to the technical field of optical detection, in particular to an optical detection system.

Background

With the continuous reduction of chip size in large scale integrated circuits, the minimum inspection size of semiconductor surface inspection matched with the manufacturing process is also continuously reduced, thereby bringing about the situation of increasing inspection difficulty.

In a semiconductor inspection system such as a wafer, a TDI camera with high sensitivity is usually used in cooperation with a scanning inspection table to realize rapid acquisition of an image of a wafer surface, so as to detect surface defects by comparing gray level differences of images between different dies (i.e., a bare Die and a wafer body, which are small units in a silicon wafer and include a single chip with a complete design and partial scribe line regions in the horizontal and vertical directions adjacent to the chip). However, there are many unstable factors during the scanning process of the wafer, such as slight bending of the structure of the inspection stage itself, structural deformation caused by temperature change, etc., which may cause relative displacement of the wafer to be tested with respect to the target surface of the TDI camera in the vertical scanning direction, which may cause relative displacement between Die images for inspection.

Obviously, for the detection method for detecting defects by using image gray scale difference, when the images used for difference have relative displacement on the wafer structure, some imaging errors can be caused, the sensitivity of the detected defects is easily reduced, and even serious consequences such as false detection are caused. In order to correct and compensate the errors to improve the sensitivity of optical detection, the most common method is an image post-processing technique, i.e. two images are aligned before performing the difference calculation, however, in the alignment mode based on the image post-processing technique, a part of errors are often introduced in the sub-pixel alignment process, which causes the result that the signal-to-noise ratio of the defect detection is relatively free from relative displacement to be reduced, and thus the expected effect cannot be achieved.

Disclosure of Invention

The technical problem that this application mainly solved is: how to physically correct imaging errors caused by structural deformation of a semiconductor detection table.

In order to solve the above technical problem, the present application provides an optical inspection system, including: the detection table is used for bearing a piece to be detected; the illumination assembly is used for projecting illumination light to a piece to be detected borne on the detection table; the illumination light is used for generating first reflection light after being projected to the surface of the piece to be detected; the objective lens assembly is used for adjusting the first reflected light according to a certain optical magnification and emitting first detection light; the image sensor is used for detecting first detection light along a preset scanning direction and generating a corresponding optical image; the linear moving assembly is used for adjusting the moving position of the objective lens assembly in a preset linear direction, wherein the preset linear direction and the preset scanning direction keep orthogonal to the optical image of the objective lens assembly.

The linear moving assembly comprises a linear sliding rail; the objective lens assembly is arranged on the linear slide rail; the linear slide rail is used for sliding in a reciprocating manner in a preset linear direction and driving the objective lens assembly to generate a preset offset distance in the sliding process; the offset distance produced by the objective lens assembly is related to the altered offset distance of the first detection light.

The optical detection system comprises a plurality of objective lens assemblies, and the optical magnifications of the objective lens assemblies are different; the plurality of objective lens assemblies are respectively arranged on the linear slide rail; the linear slide rail is also used for switching any one objective lens assembly to the transmission light path of the first reflected light through self sliding.

The linear moving assembly also comprises a motor and a rotating wheel; the rotating wheel is in running fit with the linear sliding rail, and the motor is used for driving the rotating wheel to rotate in the forward direction or in the reverse direction and driving the linear sliding rail to slide in a reciprocating mode in the process of forward rotation or reverse rotation of the rotating wheel.

The number of the objective lens assemblies is at least three, and the distance between every two adjacent objective lens assemblies on the linear slide rail is kept consistent

The optical detection system also comprises a spectroscope; the spectroscope is obliquely arranged on a transmission light path of the first detection light and obliquely opposite to the illumination assembly; the spectroscope is used for separating a part of the illumination light generated by the illumination assembly and reflecting the illumination light into the objective lens assembly, and the illumination light reflected into the objective lens assembly is projected to the surface of the piece to be measured after passing through the objective lens assembly; the spectroscope is also used for separating a part of the first detection light emitted by the objective lens assembly and transmitting the part of the first detection light to a preset detection position; the image sensor is arranged on the detection position, and detects a first detection light along a preset scanning direction on the detection position.

The optical detection system further comprises a first tube mirror assembly; the first tube mirror assembly is arranged on a transmission light path of the first detection light and used for carrying out optical imaging adjustment on the first detection light emitted by the spectroscope and transmitting the first detection light after optical adjustment to the image sensor.

The optical detection system further comprises a second tube mirror assembly; the second tube mirror assembly is arranged on a transmission light path of the illumination light and used for optically adjusting the illumination of the illumination light and emitting the adjusted illumination light to the spectroscope.

The optical detection system also comprises a power assembly; the power assembly is used for driving the detection table to move, and the projected position of the surface of the piece to be detected under the illumination light is changed through the movement of the detection table.

The optical detection system also comprises a CHUCK component; the CHUCK assembly is arranged on the detection table; the CHUCK assembly is used for stabilizing the piece to be detected, so that the piece to be detected can avoid falling or relative deviation in the moving process of the detection table.

The beneficial effect of this application is:

an optical inspection system according to the above embodiments mainly includes an inspection stage, an illumination assembly, an objective lens assembly, an image sensor, and a linear movement assembly, wherein the linear movement assembly is configured to adjust a movement position of the objective lens assembly in a predetermined linear direction, the movement position of the objective lens assembly is configured to change an offset distance of inspection light, and the optical image can be aligned to a predetermined standard image by modifying the inspection light. The technical scheme utilizes the linear movement assembly to adjust the offset distance of the objective lens assembly, so that the displacement compensation can be carried out on the optical image, and the problem of relative displacement of the optical image is solved by means of physical correction. According to the technical scheme, due to the fact that displacement compensation of image features is conducted in the aspect of physical optics, accurate alignment of the same image features can be achieved, so that the influence of structural deformation of the detection table is eliminated, and the sensitivity of the system for detecting the abnormal area on the surface of the piece to be detected is improved.

Drawings

FIG. 1 is a block diagram of an optical inspection system in one embodiment of the present application;

FIG. 2 is a block diagram of an optical inspection system in accordance with another embodiment of the present application;

FIG. 3 is a schematic illustration of a single objective lens assembly linearly movable for adjustment in an embodiment of the present application;

FIG. 4 is a block diagram of an optical inspection system in accordance with another embodiment of the present application.

Detailed Description

The present application will be described in further detail below with reference to the accompanying drawings by way of specific embodiments. Wherein like elements in different embodiments have been given like element numbers associated therewith. In the following description, numerous specific details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the described features, operations, or characteristics may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of clearly describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where a certain sequence must be followed.

The ordinal numbers used herein for the components, such as "first," "second," etc., are used merely to distinguish between the objects described, and do not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

In order to overcome the problem of relative displacement of image characteristics caused by structural deformation of a semiconductor detection platform, the technical scheme corrects and compensates the relative displacement in the scanning direction of the detection target surface vertical to the image sensor of a piece to be detected through dynamic adjustment on an optical structure before the output of the image to be detected of the piece to be detected, so that the relative displacement of the same characteristics in the optical image is avoided, and the detection sensitivity of an optical detection system to the surface defect characteristics of the piece to be detected is improved.

In one embodiment, referring to fig. 1, an optical inspection system is disclosed, which mainly includes an inspection stage 11, an illumination assembly 21, an objective lens assembly 34, an image sensor 41 and a linear movement assembly 32, which are respectively described below.

The detection platform 11 is a bearing platform of the piece a to be detected, and the detection platform 11 can drive the borne piece a to be detected to move in the x-y-z direction, so that an optical imaging mechanism formed by the illumination assembly 21, the objective lens assembly 34 and the image sensor 41 can scan the whole surface of the piece a to be detected.

It should be noted that the object to be tested a may be a semiconductor product such as a wafer, a chip, etc., and since there may be defects such as flaws on the surface thereof, it is necessary to perform optical inspection on the surface thereof, so as to manage and control the quality of the product.

The lighting assembly 21 is used for projecting lighting light L1 to a to-be-detected piece A carried on the detection table 11; the illumination light is used for generating first reflection light L2 after being projected to the surface of the piece A to be measured. The illumination module 21 may employ any one of an LED, a xenon lamp, a mercury lamp, a halogen lamp, a laser plasma lamp, and a laser-driven white light illumination module lamp, so that the illumination light L1 may be white light, colored light, or laser light. It can be understood that since the illumination light L1 generates a reflected light and a scattered light after being projected on the surface of the object a, the first reflected light L2 is only a general term of light and may include a reflected light and a scattered light.

The objective lens assembly 34 is configured to adjust the first reflected light L2 at a predetermined optical magnification and emit the first detection light L3. The objective lens assembly 34 may be disposed on a transmission path of the first reflected light L2, and configured to adjust the first reflected light L2 according to a certain optical magnification, and transmit the adjusted first detection light L3 to the image sensor 41. In some cases, the system may be provided with a plurality of objective lens assemblies 34 of different magnifications or operating bands, which may be switched to meet different optical detection needs.

The image sensor 41 is configured to detect the first detection light L3 along a preset scanning direction and generate a corresponding optical image. The image sensor 41 may be provided at a predetermined detection location, and the image sensor 41 is operative to detect the first detection L3 along a predetermined scanning direction and to generate a corresponding optical image. It is understood that the image sensor 41 is a component that converts an optical signal into an electrical signal, and the generated optical image is the result of imaging the area of the surface of the object a irradiated by the illumination light L1. The image sensor 41 may be a line scan camera, preferably a TDI line scan camera.

The linear moving assembly 32 and the objective lens assembly 34 are used for adjusting the moving position of the objective lens assembly 34 in a preset linear direction, wherein the preset linear direction is orthogonal to the preset scanning direction. The purpose of such adjustment is to change the offset distance of the first detecting light L3 by the moving position of the objective lens assembly 34, and to correct the first detecting light L3 to make the optical image align with a preset standard image, which may be the optical image obtained at the initial moment of optical detection or the optical image obtained at a time point during the optical detection. It can be understood that, since the objective lens assembly 34 not only performs the magnification adjustment but also performs the slight optical path deviation function on the first reflected light L2, after the linear moving assembly 32 adjusts the linear moving position of the objective lens assembly 34, the optical path position of the first detecting light L3 will be changed, so that the position of the image point where the first detecting light L3 is transmitted to the detection position is changed.

The linear moving component 32 may be a driving component such as a piezoelectric, a servo motor, or a DD motor, and may drive the objective lens component 34 to perform a linear movement, and the offset direction during the linear movement may refer to fig. 3. In order to enhance the response speed of the linear motion assembly 32, it is preferable to employ a driving member having a response frequency above 20 Hz.

In one embodiment, referring to fig. 1 and 2, the linear motion assembly 32 includes a linear slide 321. The objective lens assembly 34 is disposed on the linear slide 321. The linear slide 321 is configured to slide back and forth in a predetermined linear direction and to bring the animal mirror assembly 34 to a predetermined offset distance during the sliding process. The offset distance may be an angle manually set by a user, or an angle calculated by some acquisition and calculation units. It will be appreciated that the offset distance produced by the objective lens assembly 34 is related to the altered offset distance of the first detection light L3.

In one embodiment, referring to fig. 2, the optical detection system comprises a plurality of objective lens assemblies, such as reference numerals 34, 35, 36, 37, and the optical magnifications of the plurality of objective lens assemblies are different. The plurality of objective lens assemblies are respectively disposed on the linear slide rails 321, and the linear slide rails 321 are further configured to switch any one objective lens assembly to the transmission optical path of the first reflected light L2 by sliding of the linear slide rails 321. For example, as shown in fig. 3, during the linear movement of the linear sliding rail 321, the objective lens assembly 34 may be switched to the transmission path of the first reflected light L2, so as to adjust the first reflected light L2 by using the optical magnification of the objective lens assembly 34 itself; of course, the objective lens assembly 34 may also perform a small-amplitude offset motion along with the linear slide rail 321, so as to slightly change the optical path position of the first reflected light L2, so as to correct the first detection light L3.

In one embodiment, referring to fig. 1 and 2, the linear motion assembly 32 further includes a motor 323 and a wheel 324. The motor 323 is meshed with the linear sliding rail 321 through the rotating wheel 324; the motor 323 is used for driving the rotating wheel 324 to rotate in the forward direction or in the reverse direction, and driving the linear sliding rail 321 to slide in a reciprocating manner during the forward rotation or the reverse rotation of the rotating wheel 324. It is understood that the motor 323 can be a piezoelectric motor, a servo motor, a DD motor, etc., and the wheel 324 can be a gear, and of course, the linear guideway 321 should have a rack that matches the wheel 324.

In another embodiment, the user can manually drive the linear slide 321 to perform a linear movement, and can switch any one objective lens assembly to the transmission path of the first reflected light L2 during the linear movement. In addition, the linear sliding rail 321 may be marked with marks such as a distance, so that a user may manually rotate an objective lens assembly on the linear sliding rail 321 to a preset linear movement position, thereby performing a slight optical path deviation on the first reflected light L2, so that a slight optical path deviation also occurs on the first detection light L3 output by the objective lens assembly, and thus the first detection light L3 is corrected.

In one embodiment, the number of objective lens assemblies is at least three, and the distance between two adjacent objective lens assemblies on the linear slide 321 is kept consistent. For example, in fig. 2, the objective lens assemblies 34, 35, 36, 37 are uniformly arranged on the linear slide 321, and the distance between two adjacent objective lens assemblies on the linear slide 321 is the same, that is, the distance between the objective lens assemblies 35, 34, the distance between the objective lens assemblies 34, 36, and the distance between the objective lens assemblies 36, 37 are the same. This is to ensure that the translational slide rail 321 is convenient for accurate linear movement at a consistent distance when switching an objective lens assembly.

In one embodiment, referring to FIG. 2, the optical detection system further includes a beam splitter 23. The beam splitter 23 is obliquely disposed on the transmission path of the first detection light L3 and is obliquely opposite to the illumination assembly 21. The beam splitter 23 is configured to split a part of the illumination light L1 generated by the illumination assembly 21 and reflect the split illumination light L1 into the objective lens assembly 34, and the illumination light L1 reflected into the objective lens assembly 34 is projected onto the surface of the object a after passing through the objective lens assembly 34; the beam splitter 23 is further configured to split a part of the first detection light L3 emitted from the objective lens assembly 34 and transmit the split first detection light to a predetermined detection position. The image sensor 41 is disposed at the detection position, and detects the first detection light L3 at the detection position along a predetermined scanning direction.

In one embodiment, referring to fig. 2, the optical detection system further comprises a second tube mirror assembly 22. The second tube lens assembly 22 is disposed on the transmission light path of the illumination light L1, and is configured to perform optical illumination adjustment on the illumination light L1 and emit the adjusted illumination light L1 to the beam splitter 23.

It should be noted that the second tube lens assembly 22 may be an optically adjusted version of kohler illumination or critical illumination, which functions to create a uniform field of illumination at the focal plane of the objective lens. The spectroscope 23 may employ 50: a splitting ratio of 50, i.e. half of the light striking the beam splitter 23 is reflected and the other half is projected.

In one embodiment, referring to fig. 2, the optical detection system further comprises a first tube mirror assembly 33. The first tube mirror assembly 33 is disposed on a transmission light path of the first detection light L3, and is configured to perform optical imaging adjustment on the first detection light L3, and transmit the optically adjusted first detection light L3 to the image sensor 41, so that the image sensor 41 performs photoelectric conversion on the first detection light L3 to generate an optical image. It will be appreciated that the optical adjustment of the first tube lens assembly 33 may include focus adjustment, filter adjustment, etc.

In one embodiment, referring to FIG. 2, the optical detection system further includes a power assembly 12. The power assembly 12 is used for driving the detection table 11 to move, and the projected position of the surface of the object a under the illumination light is changed through the movement of the detection table 11. The driving component 12 can be a piezoelectric, servo motor, DD motor, etc., and can drive the detecting table 11 to move in the x-y-z direction, and to control in multiple degrees of freedom, even to drive the detecting table 11 to rotate.

In one embodiment, referring to fig. 2, the optical detection system further includes a CHUCK assembly 13. The CHUCK component 13 is arranged on the detection table 11 and used for stabilizing a piece A to be detected, so that the piece A to be detected is prevented from falling off or shifting relatively in the moving process of the detection table 11. It should be noted that, the CHUCK assembly 13 may adopt fixing manners such as pressing, adsorbing, adhering, and the like, for example, a common CHUCK component may be adopted.

In the present embodiment, referring to fig. 2, the illumination assembly 21, the second tube mirror assembly 22, the beam splitter 23, the objective lens assembly 34, the first tube mirror assembly 33, the linear moving assembly 32, and the image sensor 41 may jointly constitute an optical imaging mechanism, wherein the illumination light L1 output by the illumination assembly 21 is coupled into the second tube mirror assembly 22, and reflected by the beam splitter 23, the illumination light L1 is projected onto the surface of the object a through the objective lens assembly 34; the first reflected light L2 formed by the surface reflection and scattering of the object a is collected by the objective lens assembly 34, the first reflected light L2 passes through the objective lens assembly 34 and is formed into the first detection light L3, the first detection light L3 passes through the beam splitter 23 and then is coupled into the first tube lens assembly 33, the first detection light L3 emitted by the first tube lens assembly 33 is finally imaged on the light sensing area of the image sensor 41, and the image sensor 41 generates an optical image of one frame.

Note that, if the scanning direction of the image sensor 41 is the z-axis in fig. 1, the position of the image point of the first detection light L3 emitted from the first tube mirror assembly 33 at the detection position varies, and the variation is performed in the direction perpendicular to the scanning direction of the image sensor 41, that is, in the x-axis.

It will be appreciated that the aforementioned optical imaging mechanism should be enabled to scan the entire surface of the object a during the movement of the inspection stage 11. Taking a conventional 12-inch wafer as an example, the scanning area supported during the movement of the inspection stage 11 at least satisfies 300mm × 300mm.

It should be noted that, for example, slight bending of the structure of the inspection station 11 itself, structural deformation caused by temperature change, etc., may cause relative displacement of the object a with respect to the target surface of the image sensor 41 in the direction perpendicular to the scanning direction, which may cause relative displacement between optical images for optical inspection. The optical imaging mechanism drives the objective lens assembly 34 to perform corresponding linear displacement, thereby implementing the correction compensation of the relative displacement of the optical image.

The process of adjusting the linearly moving position of the objective lens assembly 34 will be described below with reference to fig. 1, 2, and 3.

In fig. 1 to 3, a defect area is formed on the device a to be detected and is denoted by a, the first reflected light L2 corresponding to the point a reaches the detection area of the image sensor 41 through the objective lens assembly 34, the beam splitter 23 and the first tube lens assembly 33, an image point position of the first detection light L3 is formed on the detection area, and is denoted by a', and the optical image obtained by imaging at this time can be regarded as a standard image. Due to the structural deformation of the detection table 11, the point a on the object a to be detected may be displaced, for example, to the point b, and the displacement deviation between the point a and the point b is Δ x, so that the original image point position a 'may be displaced to the point b', and the optical image obtained by imaging at this time may be regarded as an optical image to be processed. Due to the relative displacement of the optical image, image jitter is caused, which is beneficial to the optical detection of the surface of the object A to be detected according to the optical image, so that the displacement adjustment of the image point position b' is needed. At this time, the point a' may be used as a pixel reference point, an offset value (e.g., an offset pixel value) of the optical image relative to the standard image in the scanning direction perpendicular to the image sensor 41 may be calculated, and the offset distance of the objective lens assembly 34 may be obtained through further conversion according to the offset value; the objective lens assembly 34 can then be offset adjusted by the linear slide 321 in the linear moving assembly 32, and when the linear slide 321 drives the objective lens assembly 34 to move linearly to the position shown by the objective lens assembly 34', the linear moving distance of the objective lens assembly 34' will also be Δ x. At this time, the optical path position of the objective lens assembly 34 'for the first detecting light L3 is changed to the optical path position shown by the first detecting light L3', and then the image point position of the first detecting light L3 is shifted from the point b 'to the point a' so as to satisfy the requirement that the point b 'and the point a' are overlapped, so that the optical image is relatively shifted to the position of the standard image, so that the optical image is aligned with the standard image.

It should be noted that, the process of calculating the offset value of the image point position b 'relative to a' and the offset distance of the objective lens assembly 34 in the above description may be a result of manual calculation, and after the offset distance of the objective lens assembly 34 is obtained through manual calculation, the linear moving assembly 32 is manually operated to adjust the linear offset position of the objective lens assembly 34, so that the alignment between the optical image and the standard image can be achieved only after the objective lens assembly 34 is linearly offset-adjusted according to the offset distance.

It will be appreciated that in some cases, the calculation of the offset value of the pixel position b 'with respect to a' and the offset distance of the objective lens assembly 34, as well as the drive control of the linear motion assembly 32, may be performed by logic circuits without human intervention.

Such as fig. 4, an optical inspection system is provided, which comprises an optical imaging mechanism 2, an acquisition calculation unit 51, a control unit 52 and an inspection station 11. The optical imaging mechanism 2 may be a mechanism composed of the illumination assembly 21, the second tube mirror assembly 22, the beam splitter 23, the objective lens assembly 34, the first tube mirror assembly 33, the linear moving assembly 32, and the image sensor 41 in fig. 2. The acquiring and calculating unit 51 is configured to control the motion of the detecting table 11, and in the process of driving the to-be-detected object fixed by the CHUCK component 13 (i.e., CHUCK) to move, the image sensor 41 may continuously detect the to-be-detected object to obtain an optical image, and the acquiring and calculating unit 51 obtains a frame of optical image from the image sensor 41. Moreover, the acquisition computing unit 51 is also used to compute an offset value of the optical image with respect to a preset standard image in a direction perpendicular to the scanning direction of the image sensor 41; the standard image may be an optical image obtained at an initial time of optical detection, an optical image obtained at a certain time point in the optical detection process, or a previous optical image obtained in the optical detection process; since the offset value of the optical image relative to the standard image needs to be calculated, the optical image and the standard image may contain the same image feature, which may be used as a reference point for offset calculation, for example, the imaging point a' corresponding to the point a in fig. 3 may be used as a reference point for offset calculation. Next, the acquisition calculating unit 51 converts the offset value to obtain the offset distance of the objective lens assembly 34. Then, the acquisition and calculation unit 51 sends a control command to the control unit 52, so that the control unit 52 controls the linear moving assembly 32, the linear moving assembly 32 drives the objective lens assembly 32 to perform linear offset adjustment according to the calculated offset distance, and the offset distance of the objective lens assembly 32 is changed to compensate the image point position of the first detection light L3, so that the optical image generated by re-detection is aligned with the standard image.

For example, when the acquiring and calculating unit 51 calculates an offset value of the optical image with respect to a preset standard image in a direction perpendicular to the scanning direction of the image sensor 41, the following processing procedures are specifically included: the acquisition and calculation unit 51 selects a reference feature point from the standard image, where the reference feature point may be an imaging feature position corresponding to a defective area on the surface of the object a. The acquisition computing unit 51 obtains an alignment feature point belonging to the same image feature as the reference feature point from the optical image, where the alignment feature point may be an imaging feature position of the reference feature point after relative displacement occurs. The acquisition calculation unit 51 calculates a pixel difference value of the registration feature point compared to the reference feature point in the scanning direction perpendicular to the image sensor 41. The acquisition computing unit 51 may obtain an offset value according to the pixel difference, for example, the offset value may be represented by the number of pixels offset or the pixel distance offset, or may even be in pixel units.

For example, when the acquisition calculating unit 51 obtains the offset distance of the objective lens assembly 34 by conversion according to the offset value, the method specifically includes the following processing steps: the acquisition and calculation unit 51 converts the offset value according to a preset function curve to obtain a corresponding function value; the function curve is used to represent a linear relationship between the offset value and the offset distance, i.e. one offset value corresponds to only one offset distance. The acquisition calculating unit 51 determines the offset distance of the objective lens assembly 34 based on the converted function value.

Further, the acquisition computing unit 51 is further configured to perform the following processing procedures: after the optical image generated by the re-detection is aligned with the standard image, the collecting and calculating unit 51 will eliminate the imaging jitter of the optical image, which is beneficial to optically detecting the surface of the object a according to the optical image, and then the collecting and calculating unit can detect the surface defect feature of the object a according to the optical image generated by the re-detection, so as to obtain the position and/or type of the surface defect feature of the object a. It will be appreciated that the prior art inspection methods are considered herein to be used since the inspection methods for defective features (i.e., defect features) of images are already commonly used in optical inspection systems.

Those skilled in the art will appreciate that all or part of the functions of the various methods in the above embodiments may be implemented by hardware, or may be implemented by computer programs. When all or part of the functions of the above embodiments are implemented by a computer program, the program may be stored in a computer-readable storage medium, and the storage medium may include: a read only memory, a random access memory, a magnetic disk, an optical disk, a hard disk, etc., and the program is executed by a computer to realize the above functions. For example, the program may be stored in a memory of the device, and when the program in the memory is executed by the processor, all or part of the functions described above can be implemented. In addition, when all or part of the functions in the above embodiments are implemented by a computer program, the program may be stored in a storage medium such as a server, another computer, a magnetic disk, an optical disk, a flash disk, or a removable hard disk, and may be downloaded or copied to a memory of a local device, or may be version-updated in a system of the local device, and when the program in the memory is executed by a processor, all or part of the functions in the above embodiments may be implemented.

The present application is illustrated by using specific examples, which are only used to help understanding the technical solutions of the present application, and are not used to limit the present application. Numerous simple deductions, modifications or substitutions may also be made by those skilled in the art in light of the present teachings.

Claims (10)

1. An optical inspection system, comprising:

the detection platform is used for bearing a piece to be detected;

the illumination assembly is used for projecting illumination light to a piece to be detected carried on the detection table, and the illumination light is used for producing first reflected light after being projected to the surface of the piece to be detected;

the objective lens assembly is used for adjusting the optical magnification of the first reflected light and emitting first detection light;

the image sensor is used for detecting first detection light along a preset scanning direction and generating a corresponding optical image;

the linear moving assembly is used for adjusting the moving position of the objective lens assembly in a preset linear direction, wherein the preset linear direction is orthogonal to the preset scanning direction.

2. The optical inspection system of claim 1 wherein the linear motion assembly includes a linear slide;

the objective lens assembly is arranged on the linear slide rail;

the linear sliding rail is used for sliding in a reciprocating mode in a preset linear direction and driving the objective lens assembly to generate a preset offset distance in the sliding process, and the offset distance generated by the objective lens assembly is related to the changed offset distance of the first detection light.

3. The optical detection system of claim 2, comprising a plurality of the objective lens assemblies, wherein the plurality of objective lens assemblies have different optical magnifications;

the objective lens assemblies are respectively arranged on the linear slide rails;

the linear slide rail is also used for switching any one objective lens assembly to the transmission light path of the first reflected light through self sliding.

4. The optical inspection system of claim 2 or 3, wherein the linear motion assembly further comprises a motor and a wheel;

the rotating wheel is in running fit with the linear sliding rail, and the motor is used for driving the rotating wheel to rotate in the forward direction or in the reverse direction and driving the linear sliding rail to slide in a reciprocating mode in the process of forward rotation or reverse rotation of the rotating wheel.

5. The optical inspection system of claim 3 wherein said objective lens assemblies are at least three in number and the spacing between adjacent ones of said objective lens assemblies on said linear slide remains consistent.

6. The optical detection system of claim 3, further comprising a beam splitter;

the spectroscope is obliquely arranged on a transmission light path of the first detection light and is obliquely opposite to the illumination component;

the spectroscope is used for separating a part of the illumination light generated by the illumination assembly and reflecting the illumination light into the objective lens assembly, and the illumination light reflected into the objective lens assembly is projected to the surface of the piece to be measured after passing through the objective lens assembly;

the spectroscope is also used for separating a part of the first detection light emitted by the objective lens assembly and transmitting the first detection light to a preset detection position;

the image sensor is arranged in the detection position, and detects a first detection light along a preset scanning direction on the detection position.

7. The optical detection system of claim 6, further comprising a first tube mirror assembly;

the first tube mirror assembly is arranged on a transmission light path of the first detection light and used for carrying out optical imaging adjustment on the first detection light emitted by the spectroscope and transmitting the optically adjusted first detection light to the image sensor.

8. The optical inspection system of claim 6, further comprising a second tube mirror assembly;

the second tube mirror assembly is arranged on a transmission light path of the illumination light and is used for carrying out optical illumination adjustment on the illumination light and emitting the adjusted illumination light to the spectroscope.

9. The optical inspection system of claim 1, further comprising a power assembly;

the power assembly is used for driving the detection table to move, and the projected position of the surface of the piece to be detected under the illumination light is changed through the movement of the detection table.

10. The optical detection system of claim 9, further comprising a CHUCK component;

the CHUCK assembly is arranged on the detection table; the CHUCK assembly is used for stabilizing the piece to be detected, so that the piece to be detected can avoid falling or relative deviation in the moving process of the detection table.

Images