Optical detection system and detection method

Abstract

The application provides an optical detection system and a detection method, and relates to the field of optical detection. The system comprises a first detection mechanism, a second detection mechanism and a third detection mechanism cooperating with a moving mechanism. The first detection mechanism, the second detection mechanism and the third detection mechanism are distributed around a preset path and correspond to different detection positions respectively. The moving mechanism is configured to place a mask and drive the mask to move along the preset path. The first detection mechanism, the second detection mechanism and the third detection mechanism are respectively used for optical detection of the inner wall surface of a support frame, the front and back surfaces of a glass plate, the front surface of a protective film, the side end of the glass plate and the outer wall surface of the support frame. The application can continuously detect multiple regions of the mask, thereby simplifying the overall detection steps of the mask, improving the overall detection efficiency of the mask, and alleviating the problem of insufficient stability of the detection result caused by the influence of differences in clamping precision and environmental factors due to single-path multi-detection.

Description

Technical Field

[0001] This application belongs to the field of optical inspection technology, and in particular relates to an optical inspection system and inspection method. Background Technology

[0002] As a key component in integrated circuit photolithography, the mask's surface pattern is precisely transferred to the wafer surface through an exposure process. Masks require extremely high cleanliness and integrity during use; any minute defects, such as particles, scratches, contaminants, or film deformation, can be magnified and replicated on the wafer, leading to circuit pattern distortion or decreased product yield. Therefore, a comprehensive defect inspection is necessary before a mask is put into use.

[0003] However, existing detection methods typically require imaging detection for different detection surfaces or angles, resulting in numerous detection steps, a cumbersome process, and susceptibility to clamping accuracy and environmental factors during multiple detections, leading to low overall detection efficiency and insufficient stability of detection results.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] This application provides an optical detection system and detection method to solve or alleviate one or more technical problems in the prior art.

[0006] The first aspect of this application provides an optical inspection system for inspecting a mask, the mask including a glass plate, a support frame fixed to the front side of the glass plate, and a protective film fixed to the support frame away from the front side of the glass plate, the optical inspection system including a first inspection mechanism, a second inspection mechanism, and a third inspection mechanism that cooperate with a moving mechanism; The first detection mechanism, the second detection mechanism, and the third detection mechanism are distributed around a preset path and correspond to different detection positions respectively. The moving mechanism is configured to place the mask and drive the mask to move along the preset path. The first detection mechanism is used to perform optical detection on the inner wall surface of the support frame; The second detection mechanism is used to perform optical detection on the exposed area of ​​the front of the glass plate, the back of the glass plate, and the surface of the protective film; The third inspection mechanism is used to perform optical inspection on the side end of the glass plate and the outer wall surface of the support frame.

[0007] Optionally, when the mask plate moves to the first detection position, the first detection mechanism is located on the side of the protective film away from the glass plate, and is used to perform optical detection on the inner wall surface of the support frame.

[0008] Optionally, the first testing institution includes: An inner wall detection light source is located on the side of the protective film away from the glass plate, used to illuminate the inner wall surface of the support frame, and is reflected by the inner wall surface of the support frame to form reflected light; A reflector, positioned along the propagation path of the reflected light, is used to refract the reflected light onto the inner wall image acquisition component; The inner wall image acquisition component is disposed on the optical path after being refracted by the reflector, and is used to receive the reflected light after being refracted by the reflector and form an optical image.

[0009] Optionally, the second detection mechanism includes a first optical detection component and a second optical detection component; wherein: The first optical detection component is located on the front side of the mask; The second optical detection component is located on the back side of the mask.

[0010] Optionally, the first optical component includes a first image acquisition component and a first light source group. The first image acquisition component is located on the front side of the mask, and the first light source group is located on one side of the first image acquisition component. The first light source group is used to form multiple optical imaging environments on the front side of the mask, and the first image acquisition component is used to acquire an optical image of the corresponding area under any optical imaging environment. The second optical component includes a second image acquisition component and a second light source group. The second image acquisition component is located on the back side of the mask, and the second light source group is located on one side of the second image acquisition component. The second light source group is used to form multiple optical imaging environments on the back side of the mask, and the second image acquisition component is used to acquire an optical image of the corresponding area under any optical imaging environment.

[0011] Optionally, when the mask is moved to the third detection position, the third detection mechanism corresponds to one side end of the glass plate.

[0012] Optionally, the preset path includes a straight segment and a corner alignment segment, and the moving mechanism is configured to align the mask with the side of the third detection mechanism within the corner alignment segment.

[0013] A second aspect of this application provides an optical detection method for detecting a photomask, the photomask comprising a glass plate, a support frame fixed to the front side of the glass plate, and a protective film fixed to the support frame away from the front side of the glass plate, the method comprising: Place the mask to be inspected onto the moving mechanism; The moving mechanism moves the mask along a preset path to reach the first detection position, the second detection position, and the third detection position. Optical inspection is performed on the inner wall surface of the support frame at the first detection position using the first detection mechanism; At the second detection position, the second detection mechanism performs optical detection on the exposed area on the front of the glass plate, the back of the glass plate, and the surface of the protective film. At the third detection position, the third detection mechanism performs optical detection on the side end of the glass plate and the outer wall surface of the support frame.

[0014] Optionally, the step of performing optical inspection on the inner wall surface of the support frame at the first detection position using the first detection mechanism includes: The moving mechanism moves the mask to the first detection position. The inner wall surface of the support frame is illuminated by an inner wall detection light source; The light beam reflected from the inner wall of the support frame is refracted by a reflector onto the inner wall image acquisition component. The inner wall image acquisition component receives the reflected light after it has been refracted by the reflector to obtain an optical image of the inner wall surface of the support frame.

[0015] Optionally, the step of performing optical inspection on the inner wall surface of the support frame at the first detection position using the first detection mechanism further includes: The moving mechanism drives the mask plate to move along a preset detection track, so that the inner wall detection light source sequentially illuminates multiple areas of the inner wall surface of the support frame. Optical images of multiple regions of the inner wall surface of the support frame are obtained using an inner wall image acquisition component.

[0016] Optionally, the optical inspection of the exposed area on the front of the glass plate, the back of the glass plate, and the surface of the protective film at the second detection position via the second detection mechanism includes: The moving mechanism moves the mask to the second detection position. The surface of the protective film and the area of ​​the glass plate exposed on the front are optically inspected by the first optical inspection component. The back of the glass plate is optically inspected using a second optical inspection component.

[0017] Optionally, the optical detection of the surface of the protective film and the area of ​​the glass plate exposed on the front side using the first optical detection component includes: Bright field illumination is formed by the first light source group; Under bright field illumination, optical images of the surface of the protective film and the area of ​​the glass plate exposed on the front are acquired by the first image acquisition component; Dark-field illumination is formed by the first light source group; Under dark lighting conditions, an optical image of the surface of the protective film and the area of ​​the glass plate exposed on the front is acquired by a first image acquisition component.

[0018] Optionally, the optical inspection of the side end of the glass plate at the third detection position via the third detection mechanism includes: The moving mechanism moves the mask to the third detection position. The first side end of the glass plate and the first outer wall surface of the support frame are optically inspected by a third inspection agency. The moving mechanism drives the mask to rotate by a preset angle so that the second side of the glass plate corresponds to the third detection mechanism. The second side of the glass plate and the second outer wall of the support frame are optically inspected by a third inspection agency.

[0019] The embodiments of this application employing the above-described technical solution may have the following advantages: By integrating multiple detection mechanisms, the moving mechanism can drive the mask to complete multi-angle detection in a single movement, which means it can continuously detect multiple areas of the mask, thereby simplifying the overall detection steps of the mask and improving the overall detection efficiency of the mask. Moreover, since multiple detections are performed in a single path, it can alleviate the problem of insufficient stability of detection results caused by differences in clamping accuracy and environmental factors.

[0020] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0021] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0022] Figure 1 A schematic diagram of an optical detection system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the interference between the first detection mechanism and the mask in an embodiment of this application; Figure 3 This is a schematic diagram of the mask plate moving along a preset trajectory according to an embodiment of this application; Figure 4 This is another interference diagram between the first detection mechanism and the mask in an embodiment of this application; Figure 5 This is a schematic diagram of the first detection mechanism of the optical detection system provided in the embodiments of this application.

[0023] Figure 6 This is a schematic diagram of the second detection mechanism in an embodiment of this application detecting a mask under bright field conditions; Figure 7 This is a schematic diagram of the second detection mechanism in an embodiment of this application detecting a mask under dark conditions; Figure 8 A schematic diagram of the third detection mechanism of the optical detection system provided in the embodiments of this application.

[0024] Explanation of reference numerals in the attached figures: Second detection mechanism 30; Third detection mechanism 20; First detection mechanism 10; Mask plate 40; Moving mechanism 50; Protective film 41; Support frame 42; Glass plate 43; First bright field light source 111; First dark field light source 112; Second bright field light source 121; Second dark field light source 122; First image acquisition component 113; Second light source group; Second image acquisition component 123; Third light source 211; Third image acquisition component 213; Inner wall detection light source 311; Reflector 312; Inner wall image acquisition component 313. Detailed Implementation

[0025] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, elements, and their relative dimensions may be exaggerated. The same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0026] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0030] This application provides an optical inspection system and method. Based on this, it alleviates the problems of low inspection efficiency due to numerous and cumbersome inspection steps, and insufficient stability of inspection results caused by the influence of clamping accuracy and environmental factors during multiple inspections. See below for details.

[0031] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0032] Please see Figures 1 to 8 This application provides an optical inspection system for inspecting a mask 40. The mask 40 includes a glass plate 43, a support frame 42 fixed to one side of the glass plate 43, and a protective film 41 fixed to the support frame 42 on the side away from the glass plate 43. The support frame 43 can be four support walls evenly positioned on the front side of the glass plate, forming a rectangular frame.

[0033] The optical inspection system includes a first inspection mechanism 10, a third inspection mechanism 20, and a second inspection mechanism 30 that cooperate with the moving mechanism 50. Detailed descriptions follow: The first detection mechanism 10, the third detection mechanism 20 and the second detection mechanism 30 are distributed around a preset path and correspond to different detection positions respectively. The moving mechanism 50 is configured to place the mask plate 40 and drive the mask plate 40 to move along the preset path.

[0034] The first detection mechanism 10 is used to perform optical detection on the inner wall surface of the support frame 42, the third detection mechanism 20 is used to perform optical detection on the side end of the glass plate 43, and the second detection mechanism 30 is used to perform optical detection on the exposed area of ​​the front of the glass plate 43, the back of the glass plate 43, and the surface of the protective film 41.

[0035] In this embodiment, different detection agencies make adaptive adjustments to different parts of the mask 40 to achieve comprehensive multi-directional detection of the mask 40 based on the detection requirements of different areas of the mask 40 to be detected (such as illumination angle and imaging environment requirements).

[0036] In this embodiment, the system terminal can receive optical inspection results from multiple inspection agencies and perform unified data processing and defect analysis on the inspection results to generate a comprehensive inspection report of the mask 40. This enables the correlation analysis of inspection results from multiple parts of the mask 40, facilitating the discovery of potential defect trends across regions.

[0037] It should be noted that the first testing institution 10, the third testing institution 20 and the second testing institution 30 of this application can be distributed around the preset path in various ways.

[0038] As exemplarily illustrated, in one embodiment, the first detection mechanism 10, the third detection mechanism 20, and the second detection mechanism 30 may be sequentially distributed along a preset straight path, so that the moving mechanism 50 passes through the first detection mechanism 10, the third detection mechanism 20, and the second detection mechanism 30 sequentially on the preset straight path to complete the multi-faceted detection of the mask 40.

[0039] The positions of the first testing unit 10, the third testing unit 20, and the second testing unit 30 can be arbitrarily exchanged and adjusted. For example, they can be distributed along a preset straight path in the order of the third testing unit 20, the second testing unit 30, and the first testing unit 10, or distributed along a preset straight path in the order of the third testing unit 20, the first testing unit 10, and the second testing unit 30.

[0040] In addition, the aforementioned testing agencies can be optimized and arranged according to factors such as on-site space limitations, preheating time of lighting components, and priority of testing types (such as priority for appearance defects or priority for dimensional measurement), thereby improving testing efficiency and reducing overall system energy consumption and mechanical movement without changing the accuracy of testing results.

[0041] In other embodiments, the preset path can also be a curved path, a multi-segment zigzag path, etc., and can be adjusted according to the actual detection environment.

[0042] The optical inspection system of this application integrates multiple inspection mechanisms. The moving mechanism 50 can drive the mask plate 40 to complete multi-angle inspection in a single movement, that is, it can continuously inspect multiple areas of the mask plate 40, thereby simplifying the overall inspection steps of the mask plate 40 and improving the overall inspection efficiency of the mask plate 40. Moreover, since multiple inspections are performed in a single path, it can alleviate the problem of insufficient stability of inspection results caused by differences in clamping accuracy and environmental factors.

[0043] When the mask plate 40 moves to the first detection position, the first detection mechanism 10 is located on the side of the protective film 41 away from the glass plate 43, and is used to perform optical detection on the inner wall surface of the support frame 42.

[0044] Please see Figures 2 to 5 When inspecting the inner wall of the support frame 42, while taking into account the uniformity of the illumination spot, the height of the illumination spot on the inner wall of the support frame 42 is less than the height of the protective film 41. Therefore, the inspection process requires the inner wall image acquisition component 313 in the first inspection mechanism 10 to be moved step by step.

[0045] Specifically, the mask plate 40 can be moved along a preset detection track so that the inner wall detection light source 311 sequentially illuminates multiple areas of the inner wall surface of the support frame 42 to detect the inner wall surface of the support frame 42.

[0046] like Figure 3 As shown, the preset detection track can move from top to bottom along the height direction of the support frame 42, and then move along the horizontal direction of the support frame 42, thereby sequentially detecting multiple areas of the inner wall surface of the support frame 42.

[0047] However, in some detection scenarios, the inner wall image acquisition component 313 may physically interfere with the structure of the mask 40 during the detection process.

[0048] For an illustrative example, please refer to [link / reference]. Figures 2 to 4 The support frame 42 of the mask plate 40 is selected as a 1.5X objective lens with a working distance L of 110mm. The lens aperture D of the inner wall image acquisition component 313 is 69mm. In actual testing, the angle between the surface of the protective film 41 and the optical axis of the lens of the inner wall image acquisition component 313 is approximately 15°. Due to: L*sin ≈28.47mm<(D / 2)*cos ≈33.32mm It can be seen that during the detection process, based on the movement trajectory of the inner wall image acquisition component 313, the lens of the inner wall image acquisition component 313 will physically interfere with the surface of the protective film 41.

[0049] To resolve the above issues, please refer to Figure 5 In this embodiment, the first detection mechanism 10 includes an inner wall detection light source 311, a reflector 312, and an inner wall image acquisition component 313.

[0050] The inner wall detection light source 311 is located on the side of the protective film 41 away from the glass plate 43, and is used to irradiate the inner wall surface of the support frame 42, and is reflected by the inner wall surface of the support frame 42 to form reflected light.

[0051] A reflector 312 is disposed on the propagation path of the reflected light to refract the reflected light to the inner wall image acquisition component 313. In an optional embodiment, the reflector 312 may be located on one side of the protective film 41 and spaced apart, and installed at a 45° angle to the horizontal plane, so that the refracted light path can be refracted at a predetermined angle, thereby allowing the inner wall image acquisition component 313 to avoid the protective film 41 and thus avoid physical interference with the mask 40.

[0052] The inner wall image acquisition component 313 is disposed on the optical path after being refracted by the reflector 312, and is used to receive the reflected light after being refracted by the reflector 312 and form an optical image.

[0053] In one embodiment, the inner wall image acquisition component can employ a telecentric lens or a long working distance lens to obtain a greater imaging depth within a limited installation space and avoid image distortion. The redesigned optical path layout effectively solves the structural interference problem that exists in a few scenarios, improving the versatility of the detection system.

[0054] In an alternative embodiment, please refer to Figure 6 and Figure 7 The second detection mechanism 30 includes a first optical detection component and a second optical detection component.

[0055] The first optical detection component is located on the side where the protective film 41 is located, and the second optical detection component is located on the opposite side of the protective film 41. This allows the second detection mechanism 30 to acquire optical images of both sides of the mask 40 without additionally moving the mask 40, thereby achieving double-sided detection of the surface of the protective film 41 and the glass plate 43, avoiding the need to detect the front and back sides separately, and improving detection efficiency.

[0056] Specifically, the first optical component includes a first image acquisition component 113 and a first light source group. The first image acquisition component 113 is located on the side of the protective film 41 away from the glass plate 43, and the first light source group is located on the side of the first image acquisition component 113. The first light source group is used to form multiple optical imaging environments on the front side of the mask plate 40, and the first image acquisition component 113 is used to acquire an optical image of the corresponding area under any optical imaging environment.

[0057] The second optical component includes a second image acquisition component 123 and a second light source group. The second image acquisition component 123 is located on the side of the glass plate 43 away from the protective film 41, and the second light source group is located on the side of the second image acquisition component 123. The second light source group is used to form multiple optical imaging environments on the back of the mask plate 40, and the second image acquisition component 123 is used to acquire an optical image of the corresponding area under any optical imaging environment.

[0058] In practical applications, the first light source group is used to emit light to illuminate the mask 40, thereby forming bright-field illumination and dark-field illumination on the front side of the mask 40. Please refer to [link / reference needed]. Figure 6 and Figure 7 The first light source group may include a first bright field light source 111 that forms bright field illumination on the front side of the mask, and a first dark field light source 112 that forms dark field illumination.

[0059] The second light source group is used to form bright-field illumination and dark-field illumination on the back side of the mask 40. Specifically, the second light source group may include a second bright-field light source 121 that forms bright-field illumination on the back side of the mask, and a second dark-field light source 122 that forms dark-field illumination.

[0060] Bright field illumination involves directly illuminating the surface of the mask 40, causing surface defects to appear as images with clear contrast between bright and dark colors. It is suitable for detecting surface morphology defects such as particles and scratches.

[0061] Dark field illumination refers to the illumination of the mask 40 surface by tilting or scattering light, with only the reflected or scattered light being captured by the image acquisition component. This can highlight tiny particles, film attachments, or localized unevenness and defects, enhancing the ability to identify minute defects.

[0062] Specifically, in this embodiment, as Figure 6As shown, during bright-field illumination inspection, the lens of the first image acquisition component 113 corresponds to the front of the mask 40. The first bright-field light source 111 reflects light directly onto the front of the mask 40 along the lens direction of the first image acquisition component 113 via specular reflection. The light reflected from this side enters the first image acquisition component 113, thereby obtaining a bright-field imaging image. Bright-field imaging relies primarily on directly reflected light. Normal surface areas and defective areas have different reflection characteristics of incident light, resulting in differences in brightness or color in the image. This can be used to identify defects such as surface particles, scratches, and general pattern anomalies.

[0063] like Figure 7 As shown, during dark-field illumination, the first dark-field light source 112 can illuminate the surface of the mask 40 at a preset tilt angle, causing the reflection direction of the illuminating light to avoid the imaging optical path of the first image acquisition component 113. Normal, flat areas will not reflect light to the first image acquisition component 113, while defects such as particles, protrusions, depressions, or abrupt edge changes on the surface of the mask 40 will scatter the tilted incident light, allowing some of the scattered light to enter the first image acquisition component 113, thereby forming a dark-field imaging image. Dark-field imaging enhances the brightness contrast between the defect-scattered light and the background, enabling effective detection of tiny particles, film attachments, and subtle surface structural anomalies.

[0064] By horizontally moving the mask 40, the lens of the first image acquisition component 113 can sequentially correspond to the surface of the protective film 41 on the front of the mask 40 and the exposed area of ​​the glass plate 43 on the front (i.e. the area on the front of the glass plate 43 that is not covered by the protective film 41), so that different areas can be detected.

[0065] It is understandable that the bright field illumination detection on the front side, the dark field illumination detection on the front side, the bright field illumination detection on the back side, and the dark field illumination detection on the back side of the mask 40 can all be performed independently to avoid the impact of multiple light sources on the detection results when performed simultaneously.

[0066] The lens of the second image acquisition component 123 corresponds to the back of the mask plate 40. Its image acquisition method in bright field and dark field is basically the same as that of the first image acquisition component 113, and will not be described in detail here.

[0067] In this embodiment, when the mask plate 40 moves to the third detection position, the third detection mechanism 20 corresponds to one side end of the glass plate 43.

[0068] Please see Figure 8The third detection mechanism 20 may include a third light source 211 and a third image acquisition component 213. The third light source 211 reflects light directly onto one side of the mask 40 along the lens direction of the third image acquisition component 213 via specular reflection, allowing the reflected light to enter the third image acquisition component 213 and thus obtain an image of that side. After detecting one side of the mask 40, the third image acquisition component can be vertically moved so that its imaging position corresponds to the outer wall of the support frame to obtain an image of the outer wall of the support frame on the corresponding side.

[0069] In this embodiment, the preset path includes a straight segment and a corner alignment segment, and the moving mechanism 50 is configured to align the mask 40 with the side of the third detection mechanism 20 within the corner alignment segment.

[0070] After acquiring images of one side of the mask plate 40 and the outer wall of the corresponding support frame, the mask plate 40 can be rotated by a predetermined angle in the corner alignment section of the moving mechanism 50 so that the other side of the mask plate 40 corresponds to the third detection mechanism 20, thereby performing optical imaging detection on the other side of the mask plate 40. After rotating it multiple times, multiple sides of the mask plate 40 and multiple outer walls of the support frame can be detected, achieving multi-directional detection.

[0071] This application also provides an optical inspection method for inspecting a photomask, the photomask comprising a glass plate, a support frame fixed to the front side of the glass plate, and a protective film fixed to the support frame away from the front side of the glass plate. The optical inspection method of this application can be used to perform optical inspection on the photomask using the aforementioned optical inspection system.

[0072] Specifically, optical detection methods include multiple steps: Step S100: Place the mask to be tested on the moving mechanism.

[0073] Step S102: Move the mask along a preset path using the moving mechanism to reach the first detection position, the second detection position, and the third detection position.

[0074] It should be noted that the actual arrival order of the first, second, and third detection positions can be flexibly adjusted according to equipment configuration and detection requirements, and is not limited to a fixed order. For example, in some detection processes, the front side of the mask can be detected first, so that the mask moves to the second detection position first; in other scenarios, to reduce round-trip travel, the mask can be moved to the first or second detection position closer to the initial position first.

[0075] In addition, the order of the detection positions can be optimized based on factors such as the layout of the detection facility in the actual detection environment, on-site space limitations, preheating time of the lighting source, and priority of the detection type (such as priority for appearance defects or priority for dimensional measurement), thereby improving detection efficiency and reducing the number of mechanical movements without changing the accuracy of the detection results.

[0076] That is, there is no fixed order for the subsequent steps S104, S106 and S108, and the specific order can be adjusted according to the actual detection situation.

[0077] Step S104: At the first detection position, the inner wall surface of the support frame is optically inspected by the first detection mechanism.

[0078] Step S106: At the second detection position, the second detection mechanism performs optical detection on the exposed area of ​​the front of the glass plate, the back of the glass plate, and the surface of the protective film.

[0079] Step S108: Optical inspection is performed on the side end of the glass plate and the outer wall surface of the support frame at the third detection position by the third detection mechanism.

[0080] In this embodiment, the step of performing optical detection on the inner wall surface of the support frame at the first detection position through the first detection mechanism (step S104) may include: Step S200: Move the mask to the first detection position using the moving mechanism.

[0081] Step S202: Illuminate the inner wall surface of the support frame using an inner wall detection light source.

[0082] Step S204: The light beam reflected from the inner wall of the support frame is refracted by a reflector onto the inner wall image acquisition component.

[0083] Step S206: The inner wall image acquisition component receives the reflected light after it has been refracted by the mirror to obtain an optical image of the inner wall surface of the support frame.

[0084] By refracting the reflected light beam through a mirror, the inner wall image acquisition component that receives the light can bypass the protective film, thereby avoiding physical interference with the mask, solving the structural interference problem that exists in a few scenarios, and improving the versatility of the detection system.

[0085] Specifically, the step of performing optical detection on the inner wall surface of the support frame at the first detection position through the first detection mechanism (step S104) may further include: Step S300: The moving mechanism drives the mask plate to move along the preset detection track so that the inner wall detection light source sequentially illuminates multiple areas of the inner wall surface of the support frame.

[0086] Step S302: Obtain optical images of multiple regions of the inner wall surface of the support frame using the inner wall image acquisition component.

[0087] Specifically, such as Figure 3 As shown, the preset detection track can move from top to bottom along the height direction of the support frame, and then move along the horizontal direction of the support frame, thereby sequentially detecting multiple areas of the inner wall surface of the support frame, while the mask will not interfere with the inner wall image acquisition component.

[0088] In this embodiment, the optical detection (step S106) performed at the second detection position by the second detection mechanism on the exposed area of ​​the front of the glass plate, the back of the glass plate, and the surface of the protective film may include: Step S400: Move the mask to the second detection position using the moving mechanism.

[0089] Step S402: Perform optical inspection on the surface of the protective film and the area of ​​the glass plate exposed on the front using the first optical inspection component.

[0090] Specifically, by horizontally moving the mask to be detected, the lens of the first optical detection component can sequentially correspond to the protective film surface on the front of the mask and the exposed area of ​​the glass plate on the front, so that different areas can be detected.

[0091] Step S404: Perform optical inspection on the back of the glass plate using the second optical inspection component.

[0092] It should be noted that the detection of the front side of the mask (step S402) and the back side of the mask (step S404) are two independent detection steps. There is no fixed order between them. The front side of the mask can be detected first, or the back side of the mask can be detected first. The specific order can be adjusted according to the actual detection process.

[0093] Further, the step of optically detecting the surface of the protective film and the area of ​​the glass plate exposed on the front side using the first optical detection component (step S402) may include: Step S500: Bright field illumination is formed by the first light source group.

[0094] Step S502: Under bright field illumination, acquire optical images of the surface of the protective film and the area of ​​the glass plate exposed on the front using the first image acquisition component.

[0095] Step S504: Dark field illumination is formed by the first light source group.

[0096] Step S506: Under dark illumination conditions, acquire optical images of the surface of the protective film and the area of ​​the glass plate exposed on the front using the first image acquisition component.

[0097] It should be noted that there is no fixed order for testing the bright field illumination conditions and the dark field illumination conditions on the front of the mask. The bright field test can be performed first, or the dark field test can be performed first.

[0098] Correspondingly, the detection method for optically detecting the back of the glass plate using the second optical detection component is basically the same as the optical detection method for the front of the glass plate, and will not be described in detail here.

[0099] In this embodiment, the optical detection of the side end of the glass plate at the third detection position by the third detection mechanism (step S108) includes: Step S600: Move the mask to the third detection position using the moving mechanism.

[0100] Step S602: The first side end of the glass plate and the first outer wall surface of the support frame are optically inspected by the third inspection mechanism.

[0101] Step S604: The moving mechanism drives the mask plate to rotate by a preset angle so that the second side end of the glass plate corresponds to the third detection mechanism.

[0102] Step S606: The second side end of the glass plate and the second outer wall surface of the support frame are optically inspected by the third inspection mechanism.

[0103] After the inspection of one side of the mask is completed, the third inspection mechanism or the mask can be moved vertically to make the imaging position of the third inspection mechanism correspond to the outer wall of the support frame, so as to obtain the imaging image of the outer wall of the support frame on the corresponding side, thereby inspecting the end of the glass plate and the outer wall of the support frame on the same side.

[0104] It is understood that after each side of the glass plate is inspected, the step of rotating the mask in step S604 can be repeated. That is, the mask is rotated by a preset angle by a moving mechanism so that the other side of the glass plate corresponds to the third inspection mechanism. In this way, different ends of the glass plate and the outer wall surfaces of different sides of the support frame are inspected in a single inspection process, so as to achieve multi-directional comprehensive inspection of the mask.

[0105] The optical inspection method of this application can continuously inspect multiple areas of a mask by inspecting multiple facets of the mask in a single stroke, thereby simplifying the overall inspection steps of the mask and improving the overall inspection efficiency. Furthermore, since multiple inspections are performed in a single path, it can alleviate the problem of insufficient stability of inspection results caused by differences in clamping accuracy and environmental factors.

[0106] It should be noted that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of the component itself. For example, if a device in the drawings is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0107] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0108] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0109] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. An optical inspection system for inspecting a photomask, the photomask comprising a glass plate, a support frame fixed to the front side of the glass plate, and a protective film fixed to the support frame away from the front side of the glass plate, characterized in that, The optical inspection system includes a first inspection mechanism, a second inspection mechanism, and a third inspection mechanism that cooperate with the moving mechanism; The first detection mechanism, the second detection mechanism, and the third detection mechanism are distributed around a preset path and correspond to different detection positions respectively. The moving mechanism is configured to place the mask and drive the mask to move along the preset path. The first detection mechanism is used to perform optical detection on the inner wall surface of the support frame; The second detection mechanism is used to perform optical detection on the exposed area of ​​the front of the glass plate, the back of the glass plate, and the surface of the protective film; The third detection mechanism is used to perform optical detection on the side end of the glass plate and the outer wall surface of the support frame; The first testing institution includes: An inner wall detection light source is located on the side of the protective film away from the glass plate, used to illuminate the inner wall surface of the support frame, and is reflected by the inner wall surface of the support frame to form reflected light; A reflector, positioned along the propagation path of the reflected light, is used to refract the reflected light onto the inner wall image acquisition component; The inner wall image acquisition component is disposed on the optical path after being refracted by the reflector, and is used to receive the reflected light after being refracted by the reflector and form an optical image; The preset path includes a straight segment and a corner alignment segment, and the moving mechanism is configured to align the mask with the side of the third detection mechanism within the corner alignment segment.

2. The optical detection system according to claim 1, characterized in that, When the mask moves to the first detection position, the first detection mechanism is located on the side of the protective film away from the glass plate, and is used to perform optical detection on the inner wall surface of the support frame.

3. The optical detection system according to claim 1, characterized in that, The second detection mechanism includes a first optical detection component and a second optical detection component; wherein: The first optical detection component is located on the front side of the mask; The second optical detection component is located on the back side of the mask.

4. The optical detection system according to claim 3, characterized in that, The first optical component includes a first image acquisition component and a first light source group. The first image acquisition component is located on the front side of the mask, and the first light source group is located on one side of the first image acquisition component. The first light source group is used to form multiple optical imaging environments on the front side of the mask, and the first image acquisition component is used to acquire an optical image of the corresponding area under any optical imaging environment. The second optical component includes a second image acquisition component and a second light source group. The second image acquisition component is located on the back side of the mask, and the second light source group is located on one side of the second image acquisition component. The second light source group is used to form multiple optical imaging environments on the back side of the mask, and the second image acquisition component is used to acquire an optical image of the corresponding area under any optical imaging environment.

5. The optical inspection system according to claim 1, characterized in that, When the mask plate moves to the third detection position, the third detection mechanism corresponds to one side end of the glass plate.

6. An optical inspection method for inspecting a mask using the optical inspection system according to any one of claims 1 to 5, the mask comprising a glass plate, a support frame fixed to the front side of the glass plate, and a protective film fixed to the support frame away from the front side of the glass plate, characterized in that, The method includes: Place the mask to be inspected onto the moving mechanism; The moving mechanism moves the mask along a preset path to reach the first detection position, the second detection position, and the third detection position. Optical inspection is performed on the inner wall surface of the support frame at the first detection position using the first detection mechanism; At the second detection position, the second detection mechanism performs optical detection on the exposed area on the front of the glass plate, the back of the glass plate, and the surface of the protective film. At the third detection position, the third detection mechanism performs optical detection on the side end of the glass plate and the outer wall surface of the support frame.

7. The optical detection method according to claim 6, characterized in that, The optical inspection of the inner wall surface of the support frame at the first detection position by the first detection mechanism includes: The moving mechanism moves the mask to the first detection position. The inner wall surface of the support frame is illuminated by an inner wall detection light source; The light beam reflected from the inner wall of the support frame is refracted by a reflector onto the inner wall image acquisition component. The inner wall image acquisition component receives the reflected light after it has been refracted by the reflector to obtain an optical image of the inner wall surface of the support frame.

8. The optical detection method according to claim 7, characterized in that, The step of performing optical inspection on the inner wall surface of the support frame at the first detection position using the first detection mechanism further includes: The moving mechanism drives the mask plate to move along a preset detection track, so that the inner wall detection light source sequentially illuminates multiple areas of the inner wall surface of the support frame. Optical images of multiple regions of the inner wall surface of the support frame are obtained using an inner wall image acquisition component.

9. The optical detection method according to claim 6, characterized in that, The optical inspection of the exposed area on the front of the glass plate, the back of the glass plate, and the surface of the protective film at the second detection position via the second detection mechanism includes: The moving mechanism moves the mask to the second detection position. The surface of the protective film and the exposed area of ​​the front of the glass plate are optically inspected by the first optical inspection component. The back of the glass plate is optically inspected using a second optical inspection component.

10. The optical detection method according to claim 9, characterized in that, The optical detection of the surface of the protective film and the area of ​​the glass plate exposed on the front side by the first optical detection component includes: Bright field illumination is formed by the first light source group; Under bright field illumination, optical images of the surface of the protective film and the area of ​​the glass plate exposed on the front are acquired by the first image acquisition component; Dark-field illumination is formed by the first light source group; Under dark lighting conditions, an optical image of the surface of the protective film and the area of ​​the glass plate exposed on the front is acquired by a first image acquisition component.

11. The optical detection method according to claim 6, characterized in that, The optical inspection of the side end of the glass plate at the third detection position via the third detection mechanism includes: The moving mechanism moves the mask to the third detection position. The first side end of the glass plate and the first outer wall surface of the support frame are optically inspected by a third inspection agency. The moving mechanism drives the mask to rotate by a preset angle so that the second side of the glass plate corresponds to the third detection mechanism. The second side of the glass plate and the second outer wall of the support frame are optically inspected by a third inspection agency.

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