Line scanning optical detection system

Abstract

The utility model provides a linear scanning optical detection system, which comprises an illumination system, an imaging system, a plurality of microscope objective lenses with different multiplying power, an objective lens converter, a first linear array detection camera and a second linear array detection camera, the objective lens converter is used for switching a plurality of microscope objective lenses with different multiplying power; one of the first linear array detection camera and the second linear array detection camera is a black-and-white linear array camera for acquiring black-and-white images line by line for a detection area of an object to be detected, and the other one of the first linear array detection camera and the second linear array detection camera is a color linear array camera for acquiring color images line by line for the detection area; light emitted by the illumination system enters the detection area to generate signal light, the signal light is collected into the first linear array detection camera and / or the second linear array detection camera through the microscope objective, the first linear array detection camera and / or the second linear array detection camera collect images line by line for measuring an object to be detected, and the wafer defect detection effect can be improved.

Description

Technical Field

[0001] The present disclosure relates to optical detection technology and chip measurement technology, and particularly to a line-scan optical detection system. Background Art

[0002] In the chip manufacturing process, it is necessary to detect defects on a wafer to ensure the chip quality. With the continuous development of wafer defect detection technology, the requirements for wafer detection systems in terms of scanning speed, accuracy of detection results, etc. are constantly increasing. As an evaluation index of a wafer detection system, when the wafer size remains unchanged, the scanning speed of the wafer detection system is specified to be expressed as wafers per hour (WPH).

[0003] An industrial camera is an essential core component of a machine vision system and has different classification criteria according to different categories. Classified according to the structural characteristics of the sensor, it can be divided into an area array camera and a line array camera. Compared with an area array camera, a line array camera has a higher line frequency, and in a wafer detection system using a line array camera under the same magnification objective lens and trigger mode, a higher WPH can often be achieved.

[0004] In the process of implementing the present disclosure, the inventors of the present disclosure found through research that with the development of semiconductor technology, there are various types of wafers, and the types and degrees of defects that appear on various types of wafers may also be different. In the related art, a wafer detection system using a line array camera is usually configured with a black-and-white single line array camera, and for some wafer defects with small brightness differences, effective detection and identification cannot be performed. Summary of the Utility Model

[0005] Embodiments of the present disclosure provide a line-scan optical detection system to improve the detection effect of wafer defects.

[0006] A line-scan optical detection system provided by an embodiment of the present disclosure includes an illumination system and an imaging system. The imaging system includes a plurality of microscopic objective lenses with different magnifications, an objective lens turret, a first line array detection camera, and a second line array detection camera;

[0007] The objective lens turret is used to switch the plurality of microscopic objective lenses with different magnifications;

[0008] One of the first line array detection camera and the second line array detection camera is a black-and-white line array camera for sequentially collecting black-and-white images of the detection area of the object to be detected, and the other of the first line array detection camera and the second line array detection camera is a color line array camera for sequentially collecting color images of the detection area;

[0009] Among them, the light emitted by the illumination system is incident on the detection area to generate signal light, and the signal light is collected by the microscopic objective lens and then enters the first linear array detection camera and / or the second linear array detection camera, and the first linear array detection camera and / or the second linear array detection camera captures images row by row for measuring the object to be measured.

[0010] Optionally, in any embodiment of the present disclosure, the imaging system further includes a tube lens, the tube lens includes a first beam splitter, the first beam splitter is disposed between the first linear array detection camera and the microscopic objective lens, and the optical axes of the first beam splitter, the first linear array detection camera and the microscopic objective lens are coaxially arranged, and are used to transmit a part of the signal light rays in the detection area to the first linear array detection camera and reflect another part to the second linear array detection camera.

[0011] Optionally, in any embodiment of the present disclosure, the tube lens further includes a converging lens, the converging lens is disposed between the first beam splitter and the microscopic objective lens, and the optical axes of the converging lens, the first beam splitter, the first linear array detection camera and the microscopic objective lens are coaxially arranged, and are used for light convergence.

[0012] Optionally, in any embodiment of the present disclosure, the illumination system includes a first light source and a second light source, the first light source is a bright field light source, and the second light source is a dark field light source;

[0013] The light emitted by the first light source is incident on the detection area to form reflected light, and the reflected light is collected by the microscopic objective lens and then enters the first linear array detection camera and / or the second linear array detection camera, and the first linear array detection camera and / or the second linear array detection camera captures images row by row for measuring the object to be measured;

[0014] The light emitted by the second light source is incident on the detection area at a preset angle to form scattered light, and the scattered light is collected by the microscopic objective lens and then enters the first linear array detection camera and / or the second linear array detection camera, and the first linear array detection camera and / or the second linear array detection camera captures images row by row for measuring the object to be measured.

[0015] Optionally, in any embodiment of the present disclosure, the tube lens further includes a second beam splitter, the second beam splitter is disposed between the converging lens and the microscopic objective lens, and the optical axes of the second beam splitter, the converging lens, the first beam splitter, the first linear array detection camera and the microscopic objective lens are coaxially arranged, and are used to reflect the light emitted by the first light source to the microscopic objective lens, and then enter the detection area through the microscopic objective lens.

[0016] Optionally, in any embodiment of the present disclosure, the second light source is specifically a dark-field annular light source, and the plane where the dark-field annular light source is located is parallel to the plane where the detection object is located and perpendicular to the optical axes of the microscopic objective lens and the first line-array detection camera.

[0017] Optionally, in any embodiment of the present disclosure, a control system is further included. The control system is respectively communicatively connected to the first line-array detection camera, the second line-array detection camera, and the illumination system, and is configured to control the working states of the first line-array detection camera, the second line-array detection camera, and the illumination system.

[0018] Optionally, in any embodiment of the present disclosure, the imaging system further includes a camera adapter. The camera adapter is respectively connected to the first line-array detection camera and the second line-array detection camera, and is configured to select to use the first line-array detection camera and / or the second line-array detection camera to collect images row by row.

[0019] Optionally, in any embodiment of the present disclosure, a control system is further included. The control system is respectively communicatively connected to the camera adapter and the illumination system, and is configured to control the camera adapter to select to use the first line-array detection camera and / or the second line-array detection camera to collect images row by row.

[0020] Optionally, in any embodiment of the present disclosure, a stage for placing the object to be measured is further included. The stage is communicatively connected to the control system, and the control system is configured to control the movement of the stage so that the imaging system scans different detection areas of the object to be measured.

[0021] An embodiment of the present disclosure provides a dual-line-scan optical detection system with switchable magnification and equipped with two line-array detection cameras, including an illumination system and an imaging system. The imaging system includes multiple microscopic objectives with different magnifications, an objective turret, a first line-array detection camera, and a second line-array detection camera. The objective turret is used to switch multiple microscopic objectives with different magnifications. One of the first line-array detection camera and the second line-array detection camera is a black-and-white line-array camera, and the other is a color line-array camera for acquiring color images row by row for a detection area. The signal light generated after the light emitted by the illumination system is incident on the detection area is reflected by the microscopic objective into the first line-array detection camera and / or the second line-array detection camera, and the first line-array detection camera and / or the second line-array detection camera acquire images row by row for measuring a to-be-detected object. When the structure based on the embodiment of the present disclosure is used for wafer detection (i.e., the to-be-detected object is a wafer), the multi-magnification microscopic objectives can meet the requirements for the field of view and resolution in the detection of different types of wafers, avoid performance waste while ensuring imaging accuracy and WPH, and avoid the limitation of the field of view on WPH under a single-magnification microscopic objective; through the black-and-white line-array camera and the color line-array camera, effective detection and identification of wafer defects with various brightness differences can be satisfied. Thus, the line-scan optical detection system of this embodiment can switch microscopic objectives with different magnifications to adapt to the scene requirements of different fields of view and resolutions, and the dual-line-scan cameras are used in a multi-functional combination, which can meet the requirements for various wafer types and defect detections, and effectively improve the accuracy and efficiency of wafer detection.

[0022] The technical solutions of the present disclosure will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings forming a part of the specification depict embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure.

[0024] Referring to the drawings, the present disclosure can be more clearly understood according to the following detailed description, where:

[0025] Figure 1 is a schematic structural diagram of an embodiment of the line-scan optical detection system of the present disclosure.

[0026] Figure 2 is a schematic structural diagram of another embodiment of the line-scan optical detection system of the present disclosure.

[0027] Figure 3 is a schematic structural diagram of yet another embodiment of the line-scan optical detection system of the present disclosure.

[0028] Figure 4 is a schematic structural diagram of still another embodiment of the line-scan optical detection system of the present disclosure.

[0029] Figure 5This is a schematic structural diagram of yet another embodiment of the line-scanning optical detection system of the present disclosure.

[0030] Figure 6 This is a line-scanning schematic diagram of the line-scanning optical detection system of the present disclosure.

[0031] Figure 7 This is another line-scanning schematic diagram of the line-scanning optical detection system of the present disclosure. Detailed implementation manners

[0032] Now, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure.

[0033] Those skilled in the art can understand that terms such as "first", "second", etc. in the embodiments of the present disclosure are only used to distinguish different steps, devices, or modules, etc., and neither represent any specific technical meaning nor indicate an inevitable logical order between them.

[0034] It should also be understood that in the embodiments of the present disclosure, "a plurality of" may refer to two or more, and "at least one" may refer to one, two, or more.

[0035] It should also be understood that for any component, data, or structure mentioned in the embodiments of the present disclosure, without clear limitation or contrary indication in the context, it is generally understood as one or more.

[0036] In addition, the term "and / or" in the present disclosure is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present disclosure generally represents an "or" relationship between the associated objects before and after.

[0037] It should also be understood that the present disclosure emphasizes the differences between various embodiments. Their similarities or similarities can be referred to each other. For the sake of brevity, they will not be elaborated one by one.

[0038] At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0039] The following description of at least one exemplary embodiment is actually merely illustrative and in no way limits the present disclosure or its application or use.

[0040] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0041] It should be noted that like reference numerals and letters indicate like items in the following figures. Therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0042] Figure 1 This is a schematic structural diagram of an embodiment of the line-scan optical detection system of the present disclosure. As Figure 1 shown, the line-scan optical detection system of the embodiment of the present disclosure includes an illumination system 1 and an imaging system 2. Among them, the imaging system 2 includes a plurality of microscopic objectives 21 with different magnifications, an objective turret 22, a first line-array detection camera (i.e., line-array camera) 23, and a second line-array detection camera (i.e., line-array camera) 24. Among them, the plurality of microscopic objectives 21 with different magnifications may include, for example, but are not limited to, 3.5X, 5X, 10X microscopic objectives, etc. In the embodiment of the present disclosure, the plurality of microscopic objectives 21 with different magnifications can be matched with a plurality of microscopic objectives with different magnifications according to actual needs. The specific magnifications of the microscopic objectives that can be matched in the embodiment of the present disclosure are not limited.

[0043] The objective turret 22 is used to switch between a plurality of microscopic objectives with different magnifications. If the repeating unit size of the object to be measured (such as a wafer) is too large, using a microscopic objective with a higher magnification will result in a waste of resolution accuracy performance and will limit the imaging field of view, thereby affecting WPH; while if the repeating unit size of the object to be measured is small, using a microscopic objective with a lower magnification will cause the resolution to deteriorate and the accuracy to decrease. In this embodiment, by providing the objective turret 22, a microscopic objective with a suitable magnification can be selected according to the type of the object to be measured (such as the type of wafer, different types having different sizes) and the imaging resolution requirements. By switching the plurality of microscopic objectives with different magnifications to a microscopic objective with a suitable magnification through the objective turret 22 and performing scanning imaging on the object to be measured, the maximum efficiency of the hardware parameters in the line-scan optical detection system will be exerted, and it is possible to avoid the problems of insufficient or wasted hardware performance and limited WPH brought by a single-magnification microscopic objective when facing different types of objects to be measured, achieve a higher WPH while ensuring the detection accuracy, and will not cause waste of hard performance.

[0044] One of the first line-array detection camera 23 and the second line-array detection camera 24 is a black-and-white line-array camera for sequentially collecting black-and-white images of the detection area of the object to be measured (Device Under Test, DUT), and the other of the first line-array detection camera 23 and the second line-array detection camera 24 is a color line-array camera for sequentially collecting color images of the detection area. The object to be measured in the embodiment of the present disclosure may include, for example, but is not limited to, wafers, chips, etc., any object that can be measured by an optical detection system. The embodiment of the present disclosure does not limit this.

[0045] The light emitted by the illumination system 1 is incident on the detection area of the object to be measured, generating signal light. This signal light is collected by the microscopic objective lens and then enters the first linear array detection camera 23 and / or the second linear array detection camera 24. The first linear array detection camera 23 and / or the second linear array detection camera 24 acquire images line by line for measuring the object to be measured.

[0046] Based on the embodiments of the present disclosure, a dual-line-scan optical detection system with switchable magnification and equipped with two linear array detection cameras is provided. It includes an illumination system and an imaging system. The imaging system includes multiple microscopic objective lenses with different magnifications, an objective lens turret, a first linear array detection camera, and a second linear array detection camera. The objective lens turret is used to switch between multiple microscopic objective lenses with different magnifications. One of the first linear array detection camera and the second linear array detection camera is a black-and-white linear array camera, and the other is a color linear array camera for acquiring color images line by line for the detection area. The signal light generated after the light emitted by the illumination system is incident on the detection area is reflected by the microscopic objective lens into the first linear array detection camera and / or the second linear array detection camera. The first linear array detection camera and / or the second linear array detection camera acquire images line by line for measuring the object to be measured. When the structure based on the embodiments of the present disclosure is used for wafer detection (i.e., the object to be measured is a wafer), the multi-magnification microscopic objective lens can meet the requirements for the field of view and resolution in the detection of different types of wafers, avoid performance waste while ensuring imaging accuracy and WPH, and avoid the limitation of the field of view on WPH under a single-magnification microscopic objective lens; through the black-and-white linear array camera and the color linear array camera, it can meet the effective detection and identification of wafer defects with various brightness differences. Therefore, the dual-line-scan optical detection system of this embodiment can switch different magnifications of microscopic objective lenses to adapt to the scene requirements of different fields of view and resolutions, and the dual-line-scan cameras can be used in a multi-functional combination, which can meet the requirements for the detection of various wafer types and defects, and effectively improve the accuracy and efficiency of wafer detection.

[0047] In a specific application, the objective lens turret 22 can be realized by a rotatable turntable along the circumference. Multiple microscopic objective lenses with different magnifications are installed on this turntable. When the turntable rotates along the circumference, different magnifications of microscopic objective lenses can be switched, enabling the microscopic objective lens to image the detection area of the object to be measured at the corresponding magnification. Additionally, the objective lens turret 22 can also be realized in other ways, as long as it can switch different magnifications of the microscopic objective lens 21. The embodiments of the present disclosure do not limit the specific implementation manner of the objective lens turret 22.

[0048] Figure 2 This is a schematic structural diagram of another embodiment of the line-scan optical detection system of the present disclosure. As Figure 2 shown, in Figure 1Based on the illustrated embodiments, in the line-scanning optical detection system of this embodiment, the imaging system 2 may further include a tube lens 25. In some implementation manners, the tube lens 25 may include a first beam splitter 251, which is disposed between the first line-array detection camera 23 and the microscopic objective lens 21. For example, it may be disposed at a position of the tube lens 25 close to the imaging end, and the optical axes of the first beam splitter 251, the first line-array detection camera 23, and the microscopic objective lens 21 are coaxially arranged, for transmitting a part of the signal light rays of the detection area of the object to be measured to the first line-array detection camera 23 and reflecting the other part to the second line-array detection camera 24. In a specific implementation, the first beam splitter 251 may be implemented by a semi-transmissive and semi-reflective flat beam splitter, or the first beam splitter 251 may also be implemented by a beam splitting prism, etc. The embodiments of the present disclosure do not limit this.

[0049] Optionally, in some other implementation manners, the tube lens 25 may further include a converging lens 252, which is disposed between the first beam splitter and the microscopic objective lens 21, and the converging lens 252 is coaxially arranged with the first beam splitter 251, the first line-array detection camera 23, and the microscopic objective lens 21 for converging light rays.

[0050] Figure 3 It is a schematic structural diagram of another embodiment of the line-scanning optical detection system of the present disclosure. As Figure 3 shown, in some implementation manners, the illumination system 1 includes a first light source 11 and a second light source 12. Among them, the first light source 11 is a bright-field light source, and the second light source 12 is a dark-field light source. The light rays emitted by the first light source 11 form reflected light after entering the detection area of the object to be measured. The reflected light is collected by the microscopic objective lens 21 into the first line-array detection camera 23 and / or the second line-array detection camera 24, and the first line-array detection camera 23 and / or the second line-array detection camera 24 collect images row by row for measuring the object to be measured. The light rays emitted by the second light source 12 form scattered light after entering the detection area of the object to be measured at a preset angle. The scattered light is collected by the microscopic objective lens 21 into the first line-array detection camera 23 and / or the second line-array detection camera 24, and the first line-array detection camera 23 and / or the second line-array detection camera 24 collect images row by row for measuring the object to be measured.

[0051] The first light source 11 and the second light source 12 in the embodiments of the present disclosure may be LEDs, LCDs, or other forms of light sources, as long as they can provide illumination beams. The embodiments of the present disclosure do not limit the specific forms of the first light source 11 and the second light source 12.

[0052] In this embodiment, when the first line array detection camera 23 is a black and white line array camera and the second line array detection camera 24 is a color line array camera, the first line array detection camera 23, the microscopic objective lens 21, and the illumination system 1 can form a coaxial bright field and dark field detection unit, and the second line array detection camera 24, the microscopic objective lens 21, and the first light source 11 can form a color camera re-inspection unit. The objective lens turret 22 and the microscopic objective lens 21 can form an objective lens switching system to switch to microscopic objective lenses with different magnifications, such as microscopic objective lenses with common magnifications of 3.5X, 5X, 10X, etc.

[0053] In this embodiment, both a bright field light source and a dark field light source are provided in the illumination system. For defects that are not easily detected under coaxial bright field conditions, such as scratches and residual glue (e.g., wafer defects), the dark field light source can be used for detection in combination, enabling effective detection of such defects. In addition, when the black and white line array camera is combined with the color line array camera, the color line array camera can perform color image scanning detection, enabling the black and white line array camera to detect defects with little difference in brightness but distinguishable in Red, Green and Blue (RGB). Thus, the multi-magnification microscopic objective lenses in the embodiments of the present disclosure combined with black and white and color double line array cameras can meet the requirements for detecting most wafer types and defects, enabling defect detection for most types of wafers and effectively improving the accuracy and efficiency of wafer detection.

[0054] Optionally, in some specific implementation examples, the second light source 12 is specifically a dark field annular light source. The plane where the dark field annular light source is located is parallel to the plane where the detection object is located and perpendicular to the optical axes of the microscopic objective lens 21 and the first line array detection camera 23.

[0055] In this embodiment, since the second light source is a dark field annular light source, defects that are not easily detected by the bright field coaxial light source can be complemented by switching to illumination detection with the dark field annular light source, thereby increasing the accuracy and integrity of defect detection.

[0056] Optionally, referring again to Figure 3 , in some other implementation manners, the tube lens 25 further includes a second beam splitter 253. The second beam splitter 253 is disposed between the converging lens 252 and the microscopic objective lens 21, and the second beam splitter 253 is coaxially arranged with the optical axes of the converging lens 252, the first beam splitter 251, the first line array detection camera 23, and the microscopic objective lens 21, and is used to reflect the light emitted by the first light source 11 to the microscopic objective lens 21, and the light is incident on the detection area of the object to be measured through the microscopic objective lens 21. In a specific implementation, the second beam splitter 253 can be implemented by a semi-transmissive and semi-reflective flat beam splitter, or the second beam splitter 253 can also be implemented by a beam splitting prism, etc. The embodiments of the present disclosure do not limit this.

[0057] Figure 4 The figure is a schematic structural diagram of yet another embodiment of the line-scanning optical detection system of the present disclosure. As Figure 4 shown, based on any of the above Figures 1 - 3 embodiments, the line-scanning optical detection system of this embodiment further includes a control system 3, which is respectively communicatively connected to the first line-array detection camera 23, the second line-array detection camera 24, and the illumination system 1, and is used to control the working states of the first line-array detection camera 23, the second line-array detection camera 24, and the illumination system 1, that is, to control whether the first line-array detection camera 23, the second line-array detection camera 24, and the illumination system 1 are working (i.e., whether they are in a working state). When the illumination system 1 includes a first light source 11 and a second light source 12, the control system 3 can specifically control the working states of the first light source 11 and the second light source 12. Optionally, the control system 3 can also control the working parameters of the first line-array detection camera 23 and the second line-array detection camera 24 (such as the focal length, frame rate, etc. of the camera 23) according to the user's instructions, and control the working parameters of the illumination system 1 (such as the on / off of the light source, brightness, etc.), and can also receive and display the images collected by the first line-array detection camera 23 and the second line-array detection camera 24.

[0058] Optionally, referring further to Figure 4 , in a further embodiment, the line-scanning optical detection system of the present disclosure embodiment may further include a stage 4 for placing the object to be measured, and the stage 4 is communicatively connected to the control system 3. The control system 3 is used to control the movement of the stage 4 so that the imaging system 2 scans different detection areas of the object to be measured.

[0059] In a specific implementation, an adsorption groove may be provided on the stage 4, which can adsorb the object to be measured placed on the adsorption groove to fix the object to be measured. The specific structure and implementation manner of the stage 4 in the present disclosure embodiment are not limited. The control system 4 can control the stage 4 to move in the reverse direction at a preset scanning step distance and according to a preset scanning direction, so that the line-scanning optical detection system scans the object to be measured on the stage 4 in the preset scanning direction and at the preset scanning step distance.

[0060] Since the surface features of different types of objects to be measured (such as wafers) are complex, and the requirements for the field of view and resolution are also different, based on this embodiment, a microscope objective with a suitable magnification can be selected for various types of objects to be measured to achieve better resolution and field of view, and the scanning path and scanning step distance can be set according to the field of view. The imaging system 2 scans different detection areas of the object to be measured by moving the stage 4. Each scan obtains a frame of image, and multiple frames of images obtained by multiple scans are stitched together. Defect detection is performed based on the obtained stitched image, and better scanning and stitching effects and WPH can be achieved.

[0061] Figure 5 This is a schematic structural diagram of yet another embodiment of the line-scanning optical detection system of the present disclosure. As Figure 5 shown, based on any of the above Figures 1 - 3 embodiments, in the line-scanning optical detection system of this embodiment, the imaging system 2 may further include a camera adapter 26, which is respectively connected to the first line-array detection camera 23 and the second line-array detection camera 24, and is used to select to use the first line-array detection camera 23 and / or the second line-array detection camera 24 to collect images line by line. In a specific example, the camera adapter 26 may be specifically implemented by an optical path control switch, and the signal light can be transmitted to the first line-array detection camera 23 and / or the second line-array detection camera 24 through this optical path control switch, so as to select the first line-array detection camera 23 and / or the second line-array detection camera 24 to perform line-by-line imaging.

[0062] Optionally, referring again to Figure 5 , in a further embodiment, the line-scanning optical detection system of the present disclosure embodiment may further include a control system 3, which is respectively communicatively connected to the camera adapter 26 and the illumination system 1, and is used to control the camera adapter 26 to select to use the first line-array detection camera 23 and / or the second line-array detection camera 24 to collect images line by line according to the user's instruction, and to control the working parameters of the illumination system 1 (such as the on / off of the light source, brightness, etc.) according to the user's instruction. Optionally, the control system 3 may also be respectively communicatively connected to the first line-array detection camera 23 and the second line-array detection camera 24, and is used to control the working parameters of the first line-array detection camera 23 and the second line-array detection camera 24 (such as the focal length, frame rate, etc. of the camera 23) according to the user's instruction, and may also receive and display the images collected by the first line-array detection camera 23 and the second line-array detection camera 24.

[0063] Optionally, referring again to Figure 5 , in a further embodiment, the line-scanning optical detection system of the present disclosure embodiment may further include a stage 4 for placing the object to be measured, and the stage 4 is communicatively connected to the control system 3. The control system 3 is used to control the movement of the stage 4 so that the imaging system 2 scans different detection areas of the object to be measured.

[0064] In a specific implementation, an adsorption groove may be provided on the stage 4, and the object to be measured placed on the adsorption groove can be adsorbed to fix the object to be measured. The specific structure and implementation manner of the stage 4 in the present disclosure embodiment are not limited. The control system 3 can control the stage 4 to move in the reverse direction at a preset scanning step distance and according to a preset scanning direction, so that the line-scanning optical detection system scans the object to be measured on the stage 4 in the preset scanning direction and at the preset scanning step distance.

[0065] Due to the complex variety of surface features of different types of objects to be measured (such as wafers), and different requirements for the field of view and resolution, based on this embodiment, a microscope objective with an appropriate magnification can be selected for various types of objects to be measured to achieve better resolution and field of view, and the scanning path and scanning step size can be set according to the field of view. The imaging system 2 scans different detection areas of the object to be measured by moving the stage 4. Each scan obtains a frame of image, and multiple frames of images obtained from multiple scans are stitched together. Defect detection is performed based on the obtained stitched image, and a better scanning and stitching effect and WPH can be achieved.

[0066] Hereinafter, Figure 6 、 Figure 7 in the case where the object to be measured is a 12-inch wafer with a wafer diameter of 294 mm and an effective area of 67852.26 mm 2 ², the number of pixels of the line scan camera (the first line array detection camera 23 or the second line array detection camera 24) is 12480, the pixel size is 5 μm, the imaging target surface is 62.4 mm, the line frequency is 174 kHz, and the focal length f range of the tube lens 25 is 100 - 300 mm. Taking the single magnification (1X) of the microscope objective 21 as 200 mm (1X) as an example, the line scan optical detection system of the present disclosure will be further described.

[0067] Figure 6 This is a line scan schematic diagram of the line scan optical detection system of the present disclosure. As Figure 6 shown, in this application embodiment, a 3.5 magnification (3.5X) microscope objective is used, the resolution of the microscope objective is 2.75 μm, the object space line length during scanning is 17.82 mm, the equivalent distance required to scan the wafer size is 3805.81 mm, the scanning speed is 248.57 mm / s, the time required to complete the equivalent path is 15.31 s. Assuming that the line scan optical detection system's scanning line change time is fixed at 0.5 s, at this object space line length, the wafer needs to change lines 19 times during scanning. Plus, the positioning movement time of the line scan optical detection system is fixed at 21 s, then the total time for the line scan optical detection system to detect this wafer is 45.81 s, and the WPH is 79.

[0068] Figure 7 This is another line scan schematic diagram of the line scan optical detection system of the present disclosure. As Figure 7 shown, in this application embodiment, a 5 magnification (5X) microscope objective is used, the resolution of the microscope objective is 2 μm, the object space line length during scanning is 12.48 mm, the time required to complete the equivalent path is 31.24 s. At this object space line length, the wafer needs to change lines 27 times during scanning. Relative to Figure 6 the embodiment shown, with other parameters unchanged, the total time for the line scan optical detection system to detect this wafer is 65.74 s, and the WPH is 55.

[0069] If a 10X microscope objective lens is selected, the resolution of the microscope objective lens is 1um, the scanned object-side line length is 6.24mm, and the time required to complete the equivalent path is 124.98s. At this object-side line length, the wafer needs to be line-changed 53 times during scanning. With other parameters unchanged, the total time for the line-scanning optical inspection system to inspect this wafer is 172.98s, and the WPH is 21.

[0070] Based on the above Figures 6 - 7 In the embodiment shown, the first line-array detection camera 23 can complete coaxial bright-field and dark-field scanning detections, and the second line-array detection camera 24 can be used for color scanning re-inspection to identify the types of wafer defects.

[0071] Based on the above Figures 6 - 7 In the embodiment shown, it can be seen that the resolution, field of view, and WPH of the line-scanning optical inspection system affect each other. In specific applications, a microscope objective lens with an appropriate magnification can be selected for scanning detection according to the wafer type and actual situation, and at the same time, the second line-array detection camera 24 is used for re-inspection to identify and confirm the types of defects.

[0072] Based on the line-scanning optical inspection system of the present disclosure, re-inspection can be performed by the second line-array detection camera 24 in the following scenarios:

[0073] In Scenario 1: When bright-field scanning detection is required, the first line-array detection camera 23 completes coaxial bright-field (i.e., under bright-field light source conditions) scanning detection, scanning a black-and-white image of a pixel area (1*n pixels, where n is an integer greater than 2). At the same time, the second line-array detection camera 24 scans a color image of this pixel area (1*n pixels) for re-inspection. At this time, the re-inspection can be completed within the scanning detection time of the first line-array detection camera 23, and no additional time is required, thus omitting the re-inspection time.

[0074] In Scenario 2: When dark-field scanning detection is required, for some objects to be measured, the first line-array detection camera 23 completes coaxial dark-field (i.e., under dark-field light source conditions) scanning detection, scanning a black-and-white image of a pixel area (1*n pixels). At the same time, the second line-array detection camera 24 scans a color image of this pixel area (1*n pixels) for re-inspection. At this time, the re-inspection can be completed within the scanning detection time of the first line-array detection camera 23, and no additional time is required, thus omitting the re-inspection time.

[0075] In Scenario 3: When performing dark-field scanning detection, for some objects to be measured, the first linear detection camera 23 completes coaxial dark-field (i.e., under dark-field light source conditions) scanning detection, scanning a black-and-white image of a pixel area (1 * n pixels), and then the second linear detection camera 24 performs bright-field (i.e., under bright-field light source conditions) scanning of the color image of this pixel area (1 * n pixels) for re-inspection. In this case, compared with a area array camera shooting an equivalent area (n * n pixel area), the time taken for the line-scan optical detection system to complete image acquisition of this equivalent area (n * n pixel area) through n scans is also shorter than the time required for the area array camera to scan once, reducing the detection time compared with the area array camera;

[0076] In Scenario 4: In Scenario 3, if a defective area (assumed size 2 * 2 pixels) is found after the first linear detection camera 23 has scanned m pixel areas, when using the second linear detection camera 24 for bright-field scanning re-inspection, it is possible to selectively use the second linear detection camera 24 to scan this defective area (2 * 2 pixels) or an area slightly larger than this defective area (such as 2 * n, 4 * n pixels, etc.), and it is possible to quickly and clearly scan a color image of this defective area or an area slightly larger than this defective area, without the need to re-scan the entire area array detection area like an area array camera. Because the large field of view of the area array camera necessarily results in a loss of resolution, thus affecting the clarity of the scanned image. Therefore, compared with using an area array camera for re-inspection, it is possible to improve the efficiency and accuracy of re-inspection.

[0077] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0078] The block diagrams of the devices, equipment, and systems involved in this disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any way. Words such as "including", "comprising", "having", etc. are open-ended terms, meaning "including but not limited to", and can be used interchangeably with each other. The word "or" and "and" used here refer to the word "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with each other.

[0079] The systems of the present disclosure may be implemented in many ways. For example, the systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. It should also be noted that in the systems of the present disclosure, each component or each step may be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.

[0080] The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the present disclosure and the practical application, and to enable others of ordinary skill in the art to understand the present disclosure and design various embodiments with various modifications suited to the particular use.

Claims

1. A line-scanning optical detection system, characterized in that It includes an illumination system and an imaging system. The imaging system includes multiple microscope objectives with different magnifications, an objective turret, a first line array detection camera, and a second line array detection camera; The objective turret is used to switch the multiple microscope objectives with different magnifications; One of the first line array detection camera and the second line array detection camera is a black and white line array camera for sequentially collecting black and white images of the detection area of the object to be measured, and the other of the first line array detection camera and the second line array detection camera is a color line array camera for sequentially collecting color images of the detection area; Wherein, the light emitted by the illumination system is incident on the detection area to generate signal light. The signal light is collected by the microscope objective and then reaches the first line array detection camera and / or the second line array detection camera, and the first line array detection camera and / or the second line array detection camera sequentially collects images for measuring the object to be measured.

2. The system according to claim 1, wherein The imaging system further includes a tube lens. The tube lens includes a first beam splitter. The first beam splitter is arranged between the first line array detection camera and the microscope objective, and the optical axes of the first beam splitter, the first line array detection camera, and the microscope objective are coaxially arranged, and is used to transmit a part of the signal light of the detection area to the first line array detection camera and reflect the other part to the second line array detection camera.

3. The system according to claim 2, wherein The tube lens further includes a converging lens. The converging lens is arranged between the first beam splitter and the microscope objective, and the optical axis of the converging lens is coaxially arranged with the first beam splitter, the first line array detection camera, and the microscope objective, and is used for light convergence.

4. The system according to claim 3, wherein The illumination system includes a first light source and a second light source. The first light source is a bright field light source, and the second light source is a dark field light source; The light emitted by the first light source is incident on the detection area to form reflected light. The reflected light is collected by the microscope objective and then reaches the first line array detection camera and / or the second line array detection camera, and the first line array detection camera and / or the second line array detection camera sequentially collects images for measuring the object to be measured; The light emitted by the second light source is incident on the detection area at a preset angle to form scattered light. The scattered light is collected by the microscope objective and then reaches the first line array detection camera and / or the second line array detection camera, and the first line array detection camera and / or the second line array detection camera sequentially collects images for measuring the object to be measured.

5. The system according to claim 4, wherein The tube lens further includes a second beam splitter. The second beam splitter is arranged between the converging lens and the microscope objective, and the optical axis of the second beam splitter is coaxially arranged with the converging lens, the first beam splitter, the first line array detection camera, and the microscope objective, and is used to reflect the light emitted by the first light source to the microscope objective, and then the light is incident on the detection area through the microscope objective.

6. The system according to claim 4, characterized in that The second light source is specifically a dark field annular light source. The plane where the dark field annular light source is located is parallel to the plane where the object to be measured is located and perpendicular to the optical axes of the microscope objective and the first line array detection camera.

7. The system according to claim 1, wherein It further includes a control system, which is communicatively connected to the first line array detection camera, the second line array detection camera, and the lighting system respectively, and is used to control the operating states of the first line array detection camera, the second line array detection camera, and the lighting system.

8. The system according to claim 1, wherein The imaging system further includes a camera adapter, which is connected to the first line array detection camera and the second line array detection camera respectively, and is used to select to use the first line array detection camera and / or the second line array detection camera to collect images line by line.

9. The system according to claim 8, wherein It further includes a control system, which is communicatively connected to the camera adapter and the lighting system respectively, and is used to control the camera adapter to select to use the first line array detection camera and / or the second line array detection camera to collect images line by line.

10. The system according to claim 7 or 9, characterized in that, It further includes a stage for placing the object to be measured, the stage is communicatively connected to the control system, and the control system is used to control the movement of the stage so that the imaging system scans different detection areas of the object to be measured.

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