Detection device and detection method thereof

Abstract

The application provides a detection device, which comprises a light emitting device, a collecting device, a spatial filter and a detection assembly; the light emitting device is used for generating incident light for irradiating a to-be-detected object, the to-be-detected object has a pattern mark on the surface, the pattern mark comprises a stripe mark, the stripe mark comprises a plurality of stripes arranged repeatedly in the same direction, and the incident light forms signal light carrying Moire stripe information after passing through the pattern mark; the collecting device is used for collecting the signal light and making the signal light propagate to the spatial filter; the spatial filter is located at a Fourier plane of the collecting device and is used for filtering the signal light collected by the collecting device and removing a low-frequency partial component in the signal light; and the detection assembly is used for imaging the Moire stripe according to the signal light filtered by the spatial filter and forming a detection image. The detection device can improve the contrast of the formed pattern and improve the detection precision.

Description

Technical Field

[0001] This invention relates to an apparatus for semiconductor manufacturing processes, and more particularly to a testing device and method for detecting the production quality of semiconductor devices. Background Technology

[0002] With the development of the semiconductor industry, the critical dimensions of semiconductor devices are gradually shrinking. In the semiconductor manufacturing process, even small production errors can cause semiconductor devices to fail, which places higher demands on semiconductor testing systems.

[0003] The semiconductor device manufacturing process involves depositing multiple stacked films on a silicon substrate, forming different patterns in each film layer through etching. During the etching process, the positions of the patterns on the upper and lower films must meet overlay requirements. To monitor the relative positional relationship between the upper and lower films, overlay marks are formed in the dicing zone of the film layer during etching. By measuring the overlay marks, the alignment error of the upper and lower pattern layers is determined, thereby monitoring the semiconductor process.

[0004] In existing technologies, overlay measurement methods include imaging-based optical measurement (IBO), diffraction-based optical measurement (DBO), and moiré fringe-based methods. Because moiré fringe-based detection methods can convert the alignment error of small-period overlay marks into the alignment error of large-period moiré fringes, the frequency of high-frequency signals exceeding the diffraction limit of the objective lens is reduced to a detectable frequency range. This allows for the detection of high-frequency components of the object under test, increasing the detection range and accuracy. However, with the increasing integration of semiconductor devices, the size of overlay marks is gradually decreasing, and moiré fringe-based detection methods are increasingly showing their advantages.

[0005] However, traditional detection equipment based on moiré patterns has low detection accuracy. Summary of the Invention

[0006] To address the above problems, this invention proposes a detection device and its detection method, which can reduce interference, improve image contrast, and thus improve detection accuracy.

[0007] The present invention provides a detection device, comprising: a detection device, characterized in that it includes a light-emitting device, a collecting device, a spatial filter, and a detection component; the light-emitting device is used to generate incident light illuminating a test object, the surface of the test object having a pattern mark, the pattern mark including stripe marks, the stripe marks including multiple stripes arranged repeatedly in the same direction, the incident light forming a signal light carrying moiré fringe information after passing through the pattern mark; the collecting device is used to collect the signal light and propagate the signal light to the spatial filter; the spatial filter is located at the Fourier plane of the collecting device and is used to filter the signal light collected by the collecting device, removing the lower frequency components of the signal light; the detection component is used to image the moiré fringes based on the signal light filtered by the spatial filter, forming a detection image.

[0008] Optionally, the incident light is used to form a patterned light spot on the surface of the patterned mark, the patterned light spot including a striped light spot, the striped light spot including a plurality of stripes arranged repeatedly in the same direction, the striped light spot and the striped mark forming the moiré stripe;

[0009] Alternatively, the pattern markings include a plurality of stripe markings, among which there are a first overlapping stripe marking and a second overlapping stripe marking, the first overlapping stripe marking and the second overlapping stripe marking at least partially overlap, the first overlapping stripe marking and the second overlapping stripe marking forming the moiré stripe.

[0010] Optionally, the detection device further includes a tube mirror, used to converge mutually parallel signal light after being filtered by the spatial filter to the same point of the detection component, and to converge signal light propagating in different directions to different points of the detection component; the detection component is located at the focal plane of the tube mirror.

[0011] Optionally, the incident light is incident on the surface of the object under test from outside the collecting device; the detection device further includes a beam splitter for propagating the incident light toward the collecting device, the collecting device for collecting the incident light and causing the incident light to reach the surface of the object under test; the beam splitter is also used to reflect the incident light to the surface of the object under test and transmit the signal light collected by the collecting device, or to transmit the incident light to the surface of the object under test and reflect the signal light collected by the collecting device; the spatial filter is located in the optical path between the beam splitter and the collecting device, or the spatial filter is located in the optical path between the beam splitter and the detection component.

[0012] Optionally, the light-emitting device includes: one or more light-emitting components, each light-emitting component including: a light source and a shaping component, the light source being used to emit an initial light beam; the shaping component being used to shape the initial light beam to form the incident light; or, the light-emitting component includes a display screen having a display pattern and projecting the display pattern onto the surface of the object to be tested to form a patterned light spot; one or both of the extension direction of the stripes and the period of the striped light spot are adjustable.

[0013] Optionally, the spatial filter includes a light-shielding plate used to block the lower frequency components of the signal light; the center of the light-shielding plate coincides with the central axis of the beam passing through the spatial filter.

[0014] Optionally, the light-shielding plate is used to block light levels from -3 to +3, and the light-shielding plate is circular, square, or regular hexagonal.

[0015] Optionally, the spatial filter further includes: a mounting component for mounting the light-shielding sheet, the mounting component transmitting the higher frequency components of the signal light; a base fixedly connected to the mounting component; the mounting component of the spatial filter is a light-transmitting substrate, the light-shielding sheet is formed by coating the light-transmitting substrate with a light-shielding material, and the light-transmitting substrates of the mounting component and the light-shielding sheet are made of the same material.

[0016] Optionally, the pattern mark includes multiple stripe marks, among which a first stripe mark and a second stripe mark are included. The extension directions of the stripes in the first and second stripe marks form a first angle, which is a right angle or an acute angle. The incident light is used to form a pattern spot on the surface of the pattern mark. The pattern spot includes stripe spots, and the pattern spot includes multiple stripe spots, including a first stripe spot and a second stripe spot. The extension directions of the stripes in the first and second stripe spots form a second angle, which is a right angle or an acute angle. The first stripe spot is used to form a first moiré fringe with the first stripe mark, and the second stripe spot is used to form a second moiré fringe with the second stripe mark. The detection image includes an image of the first moiré fringe and an image of the second moiré fringe. The second angle is the same as the first angle.

[0017] Optionally, the test object includes multiple pattern marks located on different film layers, among which a first pattern mark and a second pattern mark are included; the detection device further includes a control device for controlling the light-emitting device and the imaging device to acquire detection images of the first pattern mark and the second pattern mark; the processing module includes: a moiré offset acquisition unit for acquiring the moiré offset between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark in the detection direction based on the first detection image and the second detection image; a detection magnification acquisition unit for acquiring the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image, wherein the detection magnification is the ratio of the feature parameter of the moiré fringe to the feature parameter of the fringe mark, and the feature parameter is spatial frequency or period; and an alignment error acquisition unit for acquiring the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification.

[0018] This invention provides a detection method, characterized by including performing detection processing on pattern markings to acquire a detection image; the detection processing steps include: generating incident light illuminating a test object through a light-emitting device, the test object having pattern markings on its surface, the pattern markings including stripe markings, the stripe markings including multiple stripes arranged repeatedly in the same direction, the incident light passing through the pattern markings forming signal light carrying moiré fringe information; collecting the signal light through a collecting device and propagating the signal light to a spatial filter; filtering the signal light from the collecting device through the spatial filter to remove lower frequency components from the signal light; and imaging the moiré fringes based on the signal light filtered by the spatial filter using a detection component to form a detection image.

[0019] Optionally, the step of generating incident light illuminating the test object through the light-emitting device, wherein the test object has a pattern mark, the pattern mark includes a stripe mark, the stripe mark includes multiple stripes arranged repeatedly in the same direction, and the incident light forms a signal light carrying moiré fringe information after passing through the pattern mark includes: generating incident light through the light-emitting device, the incident light forming a pattern light spot on the surface of the pattern mark, the pattern light spot including a stripe light spot, the stripe light spot including multiple stripes arranged repeatedly in the same direction, the stripe light spot and the stripe mark forming a moiré fringe, the incident light forming a signal light after passing through the test object, and the signal light carrying the information of the moiré fringe.

[0020] Optionally, the pattern marking includes multiple stripe markings, among which there are first overlapping stripe markings and second overlapping stripe markings, the first overlapping stripe markings and the second overlapping stripe markings at least partially overlap, and the first overlapping stripe markings and the second overlapping stripe markings form moiré fringes; the step of generating incident light illuminating the test object through the light-emitting device, the test object surface having pattern markings, the pattern markings including stripe markings, the stripe markings including multiple stripes arranged repeatedly in the same direction, and the incident light forming signal light carrying moiré fringe information after passing through the pattern markings includes: generating incident light through the light-emitting device, the incident light illuminating the overlapping portion of the first overlapping stripe markings and the second overlapping stripe markings, the incident light forming signal light after passing through the first overlapping stripe markings and the second overlapping stripe markings, and the signal light carrying the information of the moiré fringes.

[0021] Optionally, the test object includes multiple pattern marks located on different film layers, among which a first pattern mark and a second pattern mark are included; the detection method further includes: performing a first detection process on the first pattern mark to obtain a first detection image of the first pattern mark; performing a second detection process on the second pattern mark to obtain a second detection image of the second pattern mark; obtaining a moiré offset along the detection direction between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark based on the first detection image and the second detection image; obtaining a detection magnification of the detection image along the detection direction based on one or a combination of the first detection image and the second detection image, wherein the detection magnification is the ratio of the feature parameters of the moiré fringes to the feature parameters of the fringe mark, the feature parameters including spatial frequency or period; and obtaining an alignment error along the detection direction between the first pattern mark and the second pattern mark based on the moiré offset and the detection magnification.

[0022] Compared with the prior art, the technical solution of the present invention has the following technical effects:

[0023] The detection device provided by the present invention includes a spatial filter located at the Fourier plane of the collecting device. This spatial filter filters the signal light collected by the collecting device, removing lower-frequency components from the signal light. The edges of the pattern markings contain high-frequency signals, while the background of the object under test is often a low-frequency signal. By removing the lower-frequency components from the signal light, the spatial filter reduces interference signals from the background of the object under test without filtering out moiré fringe information. Therefore, the detection device can improve the contrast of the formed pattern and increase detection accuracy.

[0024] Furthermore, the incident light is incident on the surface of the object to be tested from outside the collecting device; thus, the incident light does not pass through the collecting device and the spatial filter, which can reduce the influence of the collecting device and the spatial filter on the patterned light spot, thereby reducing the difficulty of forming the patterned light spot.

[0025] Furthermore, the collecting device is also used to collect the incident light and make the incident light reach the surface of the object under test. The spatial filter is located in the optical path between the beam splitter and the collecting device. The spatial filter can also filter the incident light, remove the vertical incident component, thereby reducing the parallel light reflected by the object under test, further removing low frequency components, reducing interference signals, and improving image contrast. Attached Figure Description

[0026] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. The advantages and implementation methods of the present invention will become more apparent. The contents shown in the drawings are only used to explain the present invention and do not constitute any limitation on the present invention. The drawings are only schematic and are not strictly drawn to scale.

[0027] In the attached diagram:

[0028] Figure 1 A schematic diagram of the structure of a first embodiment of the detection device according to the present invention is shown;

[0029] Figure 2 A schematic diagram of the structure of the surface pattern marking of the object to be tested according to the present invention is shown;

[0030] Figure 3 A schematic diagram illustrating the principle of moiré fringes formation in the detection equipment of the present invention is shown.

[0031] Figures 4a-4c A schematic diagram of the structure of various embodiments of the patterned light spot formed by the detection device according to the present invention is shown;

[0032] Figure 5 A schematic diagram of the spatial filter structure of the detection device according to the present invention is shown;

[0033] Figure 6 A schematic diagram of the structure of a second embodiment of the detection device according to the present invention is shown;

[0034] Figure 7 A schematic diagram of the structure of a third embodiment of the detection device according to the present invention is shown;

[0035] Figure 8 A schematic diagram of the structure of a fourth embodiment of the detection device according to the present invention is shown;

[0036] Figure 9A flowchart illustrating the steps of a detection method using a detection device according to an embodiment of the present invention is shown.

[0037] Figure 10 A flowchart illustrating the steps of the detection process in an embodiment of the detection method using the detection equipment according to the present invention is shown. Detailed Implementation

[0038] In existing detection equipment that uses moiré fringes to detect objects, the surface pattern of the object affects the moiré fringe pattern, resulting in low contrast of the formed image and low detection accuracy.

[0039] The present invention provides a detection device, comprising: a light-emitting device, a collecting device, a spatial filter, and a detection component; the light-emitting device generates incident light illuminating a test object, the surface of which has pattern markings, the pattern markings including stripe markings, the stripe markings comprising multiple stripes arranged repeatedly in the same direction, the incident light passing through the pattern markings to form signal light carrying moiré fringe information; the collecting device collects the signal light and propagates it to the spatial filter; the spatial filter is located at the Fourier plane of the collecting device and filters the signal light collected by the collecting device, removing lower frequency components from the signal light; the detection component images the moiré fringes based on the signal light filtered by the spatial filter to form a detection image. The detection device can improve the contrast of the formed image and improve detection accuracy.

[0040] The technical solution provided by the present invention will be described in detail below with reference to the embodiments.

[0041] One or more specific embodiments of the invention will be described below. To provide a concise description of these embodiments, not all features of the actual implementation may be described in the specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous decisions must be made regarding the implementation to achieve the developer's specific objectives, such as compliance with system-related and business-related constraints, which may change from one implementation to another. Furthermore, it should be understood that such development efforts may be complex and time-consuming, but will be nothing more than routine work of design, fabrication, and manufacture to those skilled in the art who have the benefits of this disclosure.

[0042] Figure 1 This is a schematic diagram of the structure of an embodiment of the detection device of the present invention.

[0043] Figure 2 This is a schematic diagram of the pattern marking structure of the technical solution of the present invention.

[0044] Figure 3This is a schematic diagram illustrating the principle of moiré stripe formation in the detection equipment provided by the technical solution of this invention.

[0045] Please refer to Figures 1-3 The detection equipment provided by the technical solution of the present invention includes: a light-emitting device, a collecting device, a spatial filter 160, and a detection component;

[0046] A light-emitting device for generating incident light that illuminates a test object, the surface of which has a pattern mark, the pattern mark including a stripe mark, the stripe mark including multiple stripes arranged repeatedly in the same direction, the incident light passing through the pattern mark to form signal light carrying moiré fringe information;

[0047] A collection device is used to collect the signal light and propagate the signal light to the spatial filter 160;

[0048] The spatial filter 160 is located at the Fourier plane of the collecting device and is used to filter the signal light collected by the collecting device to remove the lower frequency components in the signal light.

[0049] The detection component is used to image the moiré fringes based on the signal light filtered by the spatial filter 160 to form a detection image.

[0050] In this embodiment, the incident light is used to form a patterned light spot on the surface of the patterned mark. The patterned light spot includes a striped light spot, which includes multiple stripes arranged repeatedly in the same direction. The striped light spot and the striped mark form a moiré pattern.

[0051] Specifically, the light-emitting device is used to generate incident light that illuminates the test object 100. The surface of the test object 100 has a pattern mark, which includes a stripe mark. The stripe mark includes multiple stripes arranged repeatedly in the same direction. The incident light is used to form a patterned light spot 200 on the surface of the pattern mark. The patterned light spot 200 includes a stripe light spot, which includes multiple stripes arranged repeatedly in the same direction. The stripe extension direction of the stripe light spot is parallel to or has a preset angle with the stripe extension direction of the stripe mark. The preset angle is an acute angle. The stripe light spot is used to form a moiré fringe with the stripe mark. The incident light, after passing through the pattern mark, forms a signal light, which carries information about the moiré fringe.

[0052] A striped light spot is formed on the surface of the striped mark by a light-emitting device. There is a preset angle between the striped light spot and the striped mark. The preset angle is zero or an acute angle.

[0053] It should be noted that the included angle between the two directions in the technical solution provided by the present invention refers to the smaller included angle between the two directions, that is, the included angle between the two directions can only be between 0° and 90°.

[0054] In this embodiment, the light-emitting device is used to form a striped light spot on the surface of the object to be tested 100. The striped light spot includes multiple periodically arranged stripes. That is, the striped light spot is a light spot with alternating bright and dark stripes.

[0055] The light-emitting device includes one or more light-emitting components, each including: a light source 110 for emitting an initial light beam; and a shaping component 120 for shaping the initial light beam to form the incident light, the incident light being used to form the patterned light spot 200 on the surface of the object under test 100. Alternatively, the light-emitting component includes a display screen having a display pattern and projecting the display pattern onto the surface of the object under test 100 to form the patterned light spot 200.

[0056] Specifically, in this embodiment, the light-emitting device includes a light-emitting component. In another embodiment, the light-emitting component includes multiple light-emitting components (as shown in Figure 4).

[0057] The shaping component 120 includes a diffractive optical element or a spatial modulator.

[0058] In this embodiment, the central axis of the signal light collected by the imaging device has a non-zero angle with the central axis of the incident light. The angle between the central axes is a smaller angle between the central axes.

[0059] The light-emitting device emits incident light, which forms a patterned light spot 200 on the surface of the patterned mark. The patterned light spot 200 and the patterned mark form moiré fringes. Detecting the object 100 based on the image of the moiré fringes can improve detection accuracy. Simultaneously, the imaging device has a non-zero angle between the central axis of the signal light collected and the central axis of the incident light, which allows the signal light collected by the imaging device to be separated from the incident light. This separates the light-emitting device portion that forms the patterned light spot 200 on the surface of the patterned mark from the imaging device that collects the signal light. In other words, the light-emitting device that generates the incident light does not need to be used to collect the signal light, thereby reducing the design requirements of the light-emitting device.

[0060] In this embodiment, the imaging device includes: an objective lens 130 for collecting the signal light, wherein the incident light is incident on the surface of the object 100 from outside the objective lens 130; and a detection component 150 for forming the detection image based on the signal light collected by the objective lens 130. That is, in this embodiment, the incident light does not pass through the objective lens 130, so the objective lens 130 is only used to collect the signal light, thereby reducing the requirements on the objective lens 130.

[0061] In this embodiment, the imaging device further includes a converging lens group 140, used to converge the light transmitted through the objective lens to the detection component 150.

[0062] In this embodiment, the incident angle of the incident light central axis is not the same as the exit angle of the signal light central axis; or, the incident angle of the incident light central axis, the signal light central axis, and the surface normal of the object under test 100 are not coplanar. That is, the signal light collected by the objective lens 130 is formed by the scattering of the incident light by the object under test 100, and the imaging device is used to perform dark-field detection on the object under test 100. The objective lens 130 does not collect the reflected light of the incident light. The imaging device can improve the contrast of the acquired image and improve the detection accuracy by performing dark-field detection on the object under test 100. In other embodiments, the incident light central axis and the signal light central axis are symmetrical about the surface normal of the object under test, and the imaging system is shown in Figure 4.

[0063] Specifically, in this embodiment, the incident angle of the incident light's central axis is different from the exit angle of the signal light's central axis, and the exit angle of the signal light is zero. In other embodiments, the incident angle of the incident light's central axis is zero.

[0064] Figure 2 A schematic diagram of the structure of the surface pattern marking of the object to be tested according to the present invention is shown.

[0065] Please refer to Figure 2 The pattern markings include stripe markings, which are multiple stripes that are repeated in the same direction.

[0066] Specifically, the pattern marking includes multiple stripe markings, among which there is a first stripe marking 101 and a second stripe marking 102, and the extending directions of the stripes in the first stripe marking 101 and the second stripe marking 102 form a first angle. Specifically, in this embodiment, the first angle is a right angle; in other embodiments, the first angle is an acute angle.

[0067] In this embodiment, there are two of each of the first stripe mark 101 and the second stripe mark 102; the four stripe marks have a center of symmetry.

[0068] The test object 100 includes multiple pattern marks located in different film layers, among which there are a first pattern mark and a second pattern mark.

[0069] Both the first pattern mark and the second pattern mark include a first stripe mark 101 and a second stripe mark 102; and the stripe marks of the first pattern mark and the second pattern mark have a common center of symmetry.

[0070] The stripes in the first stripe mark 101 of the first pattern mark and the second pattern mark extend in the same direction; the stripes in the second stripe mark 102 of the first pattern mark and the second pattern mark extend in the same direction.

[0071] For details, please refer to Figure 2 The first pattern mark includes: a first stripe mark 101a and a second stripe mark 102a; the second pattern mark includes: a first stripe mark 101b and a second stripe mark 102b.

[0072] In other embodiments, the first pattern mark includes only the first stripe mark, and correspondingly, the second pattern mark includes the first stripe mark; or, the first pattern mark includes only the second stripe mark, and correspondingly, the second pattern mark includes the second stripe mark.

[0073] In this embodiment, the period of the striped light spot is the same as that of the striped mark. In other embodiments, the period of the striped light spot is different from that of the striped mark.

[0074] In this embodiment, the initial light beam emitted by the light source 110 is shaped by the shaping element. The shaping component 120 includes a diffractive optical element or a spatial modulator. Alternatively, the light-emitting device includes a display screen having a display pattern, which is projected onto the surface of the object under test 100 to form a patterned light spot 200.

[0075] Figure 3 This diagram illustrates the principle of how striped light spots and striped markers form moiré fringes according to an embodiment of the present invention.

[0076] Please refer to Figure 3 Based on geometric relationships, we can conclude that:

[0077]

[0078] Where M is the period of the moiré fringe, k1 is the period of the fringe mark, k2 is the period of the fringe spot, and θ is the preset included angle.

[0079] Period refers to the distance between adjacent bright stripes or adjacent dark stripes.

[0080] To more intuitively illustrate the relationship between M and θ, the above equation is simplified as follows:

[0081] When k1 = k2 = k and θ is relatively small, M = k / θ.

[0082] From the above reasoning, it can be concluded that the larger θ is, the smaller the period of the moiré fringes. Therefore, when θ is too small, the period of the moiré fringes is too large, resulting in fewer periods of the moiré fringes in a given space. This leads to less information in the acquired image of the moiré fringes, thus reducing fitting accuracy and detection accuracy. In the technical solution of this invention, the preset included angle is an acute angle to prevent the number of periods of the moiré fringes from being too small, which would affect the accuracy of subsequent fitting.

[0083] Figures 4a-4c This is a schematic diagram of the structure of various embodiments of the patterned light spot 200 formed by the detection device of the present invention.

[0084] The patterned light spot 200 includes a striped light spot, which comprises multiple stripes arranged repeatedly in the same direction.

[0085] It should be noted that when the angle between the striped light spot and the fringe extension direction of the striped mark is too large, the period of the formed moiré fringes is easily too small, resulting in low position detection accuracy of the detected pattern mark. Conversely, when the angle between the striped light spot and the fringe extension direction of the striped mark is too small, the period of the formed moiré fringes is easily reduced for the same striped mark area, thereby reducing the accuracy of subsequent model fitting and consequently reducing detection accuracy. Specifically, in this embodiment, the angle between the striped light spot and the fringe extension direction of the striped mark is 1° to 30°, for example, 5°, 10°, or 15°. In other embodiments, the angle between the striped light spot and the fringe extension direction of the striped mark can be less than 1° or greater than 30°.

[0086] The extension direction of the striped light spot is the extension direction of the stripes in the striped light spot; the extension direction of the striped mark is the extension direction of the stripes in the striped mark.

[0087] exist Figure 4a In the illustrated embodiment, the patterned light spot 200 includes a striped light spot, that is, the patterned light spot 200 only includes a first striped light spot 210. In other words, the light-emitting device can only form one striped light spot on the marking surface at a time.

[0088] The light-emitting device is used to form multiple patterned light spots 200, each patterned light spot 200 including a striped light spot.

[0089] The light-emitting device forms multiple patterned light spots 200 on the surface of the mark at different times, and the moiré fringes formed by each patterned light spot 200 and the striped mark are acquired respectively. The stripe extension direction of each patterned light spot 200 formed at different times can be different.

[0090] The shaping component 120 forms stripe patterns with different extending directions on the surface of the pattern mark. Specifically, when the shaping component 120 is a diffraction grating, rotating the diffraction grating forms stripe patterns with different extending directions on the surfaces of the first stripe mark 101 and the second stripe mark 102. Alternatively, when the light-emitting component includes a display screen, changing the displayed image on the display screen forms stripe patterns with different extending directions on the surfaces of the first stripe mark 101 and the second stripe mark 102.

[0091] In this embodiment, the detection device further includes a control device for controlling the light-emitting device and the imaging device to acquire detection images of the first pattern mark 200 and the second pattern mark 200.

[0092] refer to Figure 4b In the second embodiment, the patterned light spot 200 includes multiple striped light spots, including a first striped light spot 210 and a second striped light spot 220. That is, the light-emitting device can simultaneously form the first striped light spot 210 and the second striped light spot 220 on the marking surface. The multiple striped markings include a first striped marking 101 and a second striped marking 102. The extension directions of the stripes in the first striped marking 101 and the second striped marking 102 have a first included angle, which is an acute angle or a right angle; the extension directions of the stripes in the first striped light spot 210 and the second striped light spot 220 have a second included angle, which is an acute angle or a right angle; the first striped light spot 210 is used to form a first moiré fringe with the first striped marking 101, and the second striped light spot 220 is used to form a second moiré fringe with the second striped marking 102.

[0093] By acquiring images of the moiré fringes of the first stripe mark 101 and the second stripe mark 102, the position information of the pattern marks along the first detection direction and the second detection direction can be obtained, respectively. The first detection direction is perpendicular to the extension direction of the first stripe mark 101 or has an acute angle with it; the second detection direction is perpendicular to the extension direction of the second stripe mark 101 or has an acute angle with it.

[0094] There is a second included angle between the extending directions of the stripes in the first striped light spot 210 and the second striped light spot 220. In this embodiment, the second included angle is the same as the first included angle. Specifically, in this embodiment, both the first included angle and the second included angle are right angles.

[0095] Specifically, in this embodiment, there are two first stripe spots 210, and each first stripe spot 210 forms a first moiré fringe with the first stripe mark 101; there are two second stripe spots 220, and each second stripe spot 220 forms a second moiré fringe with the two second stripe marks 102.

[0096] refer to Figure 4c In the third embodiment, the patterned light spot 200 includes a first striped light spot 210 and a second striped light spot 220, and the first striped light spot 210 and the second striped light spot 220 overlap. The differences between the third embodiment and the second embodiment include:

[0097] The extension direction of the first striped light spot 210 and the extension direction of the second striped light spot 220 have a non-zero angle. Specifically, the extension direction of the first striped light spot 210 is perpendicular to the extension direction of the second striped light spot 220, or there is an acute angle between the extension directions of the first striped light spot 210 and the extension directions of the second striped light spot 220.

[0098] In this embodiment, the overlapping area of ​​the first stripe spot 210 and the second stripe spot 220 completely covers the pattern mark; since the overlapping area of ​​the first stripe spot 210 and the second stripe spot 220 completely covers the pattern mark, a detection image of the first stripe spot 210 and the second stripe spot 220 can be obtained by performing an imaging process on the pattern mark once. In other embodiments, the overlapping area of ​​the first stripe spot 210 and the second stripe spot 220 partially covers the pattern mark.

[0099] In other embodiments, the pattern markings include a plurality of stripe markings, among which there are a first overlapping stripe marking and a second overlapping stripe marking, the first overlapping stripe marking and the second overlapping stripe marking at least partially overlap, the first overlapping stripe marking and the second overlapping stripe marking forming the moiré stripe.

[0100] In this embodiment, the detection device further includes a control device for controlling the light-emitting device and the imaging device to acquire a first detection image of the pattern mark 200 and a second detection image of the second pattern mark 200.

[0101] Figure 5 This is a schematic diagram of the structure of an embodiment of the testing equipment provided by the technical solution of the present invention.

[0102] The spatial filter includes a light-shielding plate 161, which is used to block the lower frequency components of the signal light; the center of the light-shielding plate 161 coincides with the central axis of the light beam passing through the spatial filter 160.

[0103] The light-shielding plate 161 is used to block light of level -3 to +3, and the light-shielding plate is circular, square or regular hexagonal.

[0104] In this embodiment, the spatial filter 160 further includes a mounting member 162 for mounting the light-shielding plate 161. The mounting member 162 transmits the higher-frequency components of the signal light. Specifically, in this embodiment, the mounting member 162 transmits signal light of level 3 or higher.

[0105] The spatial filter 160 also includes a base 163 that is fixedly connected to the mounting component.

[0106] In this embodiment, the mounting component of the spatial filter 160 is a light-transmitting substrate, and the light-shielding sheet is formed by coating the light-transmitting substrate with a light-shielding material. The light-transmitting substrates of both the mounting component and the light-shielding sheet are made of the same material. The light-transmitting substrate is glass, and the light-shielding material is nickel or chromium.

[0107] In other embodiments, the mounting element is made of an alloy.

[0108] In this embodiment, the mounting member 162 is an annular ring surrounding the light-shielding sheet. In other embodiments, the mounting member 162 is an arc-shaped ring surrounding a portion of the edge of the light-shielding sheet.

[0109] The base 163 includes: a frame for mounting the mounting member 162 and a base for fixing the frame.

[0110] The detection device further includes a processing module, which comprises:

[0111] The moiré offset acquisition unit is used to acquire the moiré offset between the moiré stripes of the first pattern mark and the moiré stripes of the second pattern mark based on the first detection image and the second detection image.

[0112] The detection magnification acquisition unit is used to acquire the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image, wherein the detection magnification is the ratio of the feature parameters of the moiré fringe to the feature parameters of the fringe marker, and the feature parameters are spatial frequency or period.

[0113] The alignment error acquisition unit is used to acquire the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification.

[0114] Specifically, the feature parameter is period, and the alignment error acquisition unit is used to acquire the alignment error between the first pattern mark and the second pattern mark based on the ratio of the moiré offset to the detection magnification; or,

[0115] The feature parameter is spatial frequency, and the alignment error acquisition unit is used to obtain the alignment error between the first pattern mark and the second pattern mark based on the product of the moiré offset and the detection magnification.

[0116] Figure 6 This is a schematic diagram of the second embodiment of the detection device provided by the present invention.

[0117] Figure 6 This is a schematic diagram of the second embodiment of the detection device of the present invention.

[0118] Please refer to Figure 6 In this embodiment, with Figure 1 The similarities between the embodiments shown will not be repeated, while the differences include:

[0119] In this embodiment, the incident light central axis and the signal light central axis are symmetrical about the surface normal of the object under test 100. That is, the imaging device in this embodiment is used for bright field imaging, and there is an acute angle between the incident light central axis and the surface normal of the object under test.

[0120] Figure 7 This is a schematic diagram of the third embodiment of the detection device of the present invention.

[0121] Please refer to Figure 7 In this embodiment, with Figure 1 The similarities between the embodiments shown will not be repeated, while the differences include:

[0122] In this embodiment, the imaging device includes: an objective lens 130 for collecting the signal light, wherein the incident light is incident from inside the objective lens 130 onto the surface of the object to be tested 100; and a detection component 150 for forming the detection image based on the signal light collected by the objective lens 130.

[0123] In this embodiment, since there is a non-zero angle between the central axis of the incident light and the central axis of the signal light, the incident light and the signal light pass through different areas of the objective lens 130 respectively. The design difficulty of the objective lens 130 can be reduced by designing different areas of the objective lens 130 respectively.

[0124] In this embodiment, the light-emitting device includes one or more light-emitting components, and the incident light from the one or more light-emitting components reaches the surface of the object to be tested 100 after being transmitted through the objective lens 130.

[0125] Figure 8 This is a schematic diagram of the fourth embodiment of the detection device of the present invention.

[0126] Please refer to Figure 8 ,and Figure 1 The similarities between the embodiments shown will not be repeated, while the differences include:

[0127] In this embodiment, the incident light passes through the objective lens 130 and is incident on the surface of the object under test. The incident angle of the central axis of the incident light is a right angle. The detection device in this embodiment is a bright-field imaging device.

[0128] In this embodiment, the detection device further includes a beam splitter 170, which is used to reflect the incident light into the objective lens 130 and to transmit the signal light collected by the objective lens into the detection component 150. In another embodiment, the beam splitter is used to transmit the incident light into the objective lens 130 and to reflect the signal light collected by the objective lens into the detection component 150.

[0129] In this embodiment, the spatial filter is located on the optical path between the beam splitter 170 and the collecting device.

[0130] The collecting device is also used to collect the incident light and make the incident light reach the surface of the object under test. The spatial filter 160 is located in the optical path between the beam splitter 170 and the collecting device. The spatial filter can also filter the incident light, remove the vertical incident component, thereby reducing the parallel light reflected by the object under test 100, further removing low frequency components, reducing interference signals, and improving image contrast.

[0131] In other embodiments, the spatial filter is located in the optical path between the beam splitter and the detection component.

[0132] Figure 9 This is a flowchart illustrating the steps of an embodiment of the detection method of the detection equipment of the present invention.

[0133] The detection equipment and Figures 1 to 8 The embodiments shown are the same, so they will not be described in detail here.

[0134] In this embodiment, the test object includes multiple pattern marks located in different film layers, and the multiple pattern marks include a first pattern mark and a second pattern mark;

[0135] Please refer to Figure 9 The detection method further includes:

[0136] Step S1: Perform a first detection process on the first pattern mark to obtain a first detection image of the first pattern mark;

[0137] Step S2: Perform a second detection process on the second pattern mark to obtain a second detection image of the second pattern mark;

[0138] Step S3: Obtain the moiré offset along the detection direction between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark based on the first detection image and the second detection image;

[0139] Step S4: Obtain the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image. The detection magnification is the ratio of the feature parameters of the moiré fringe to the feature parameters of the fringe markers. The feature parameters include spatial frequency or period.

[0140] Step S5: Obtain the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification.

[0141] Figure 10 This is a flowchart of the detection process steps in one embodiment of the detection method of the present invention.

[0142] Please refer to Figure 10 The steps of both the first and second detection processes include:

[0143] Step S11: The light-emitting device generates incident light to illuminate the test object. The test object has a pattern mark on its surface. The pattern mark includes a stripe mark. The stripe mark includes multiple stripes arranged repeatedly in the same direction. The incident light passes through the pattern mark to form signal light carrying moiré fringe information.

[0144] Step S12: Collect the signal light through the collection device and propagate the signal light to the spatial filter;

[0145] Step S13: Filter the signal light from the collection device using the spatial filter to remove the lower frequency components from the signal light;

[0146] Step S14: The detection component images the moiré fringes based on the signal light filtered by the spatial filter to form a detection image.

[0147] The spatial filter, located at the Fourier plane of the collecting device, filters the signal light collected by the collecting device, removing lower-frequency components. The edges of the pattern markings contain high-frequency signals, while the background of the object under test is often a low-frequency signal. The spatial filter removes the lower-frequency components of the signal light, reducing interference signals from the background of the object under test without filtering out moiré fringe information. Therefore, the detection device can improve the contrast of the formed pattern and increase detection accuracy.

[0148] In one embodiment, the step of generating incident light illuminating a test object by means of the light-emitting device, wherein the test object has a pattern mark, the pattern mark includes a stripe mark, the stripe mark includes a plurality of stripes arranged repeatedly in the same direction, and the incident light forms a signal light carrying moiré fringe information after passing through the pattern mark includes: generating incident light by means of the light-emitting device, the incident light forming a pattern light spot on the surface of the pattern mark, the pattern light spot including a stripe light spot, the stripe light spot including a plurality of stripes arranged repeatedly in the same direction, the stripe light spot and the stripe mark forming a moiré fringe, the incident light forming a signal light after passing through the test object, and the signal light carrying the information of the moiré fringe.

[0149] In one embodiment, the pattern marking includes a plurality of stripe markings, among which there are a first overlapping stripe marking and a second overlapping stripe marking, the first overlapping stripe marking and the second overlapping stripe marking at least partially overlap, and the first overlapping stripe marking and the second overlapping stripe marking form moiré fringes; the step of generating incident light illuminating the test object by the light-emitting device, the test object having a pattern marking, the pattern marking including stripe markings, the stripe markings including a plurality of stripes arranged repeatedly in the same direction, and the incident light forming signal light carrying moiré fringe information after passing through the pattern markings includes: generating incident light by the light-emitting device, the incident light illuminating the overlapping portion of the first overlapping stripe marking and the second overlapping stripe marking, the incident light forming signal light after passing through the first overlapping stripe marking and the second overlapping stripe marking, the signal light carrying the information of the moiré fringes.

[0150] Specifically, refer to the following: Figure 1 As shown in Figure 4, step S1 is performed to perform a first detection process on the first pattern mark 200 to obtain a first detection image of the first pattern mark; step S2 is performed to perform a second detection process on the second pattern mark 200 to obtain a second detection image of the second pattern mark.

[0151] The first detection process includes: performing the imaging process on the first pattern mark 200 once or multiple times to obtain a first detection image group of the first pattern mark 200, wherein the detection image group includes one or more detection images.

[0152] The second detection process includes: performing the imaging process on the second pattern mark 200 once or multiple times to obtain a second detection image group of the second pattern mark 200, wherein the second detection image group includes one or more detection images.

[0153] In this embodiment, the pattern mark 200 includes multiple stripe marks, including a first stripe mark 101 and a second stripe mark 102. The extension directions of the stripes in the first stripe mark 101 and the second stripe mark 102 have a first included angle, which is a right angle or an acute angle.

[0154] The detection processing steps include: performing the imaging processing on the plurality of stripe marks respectively to obtain sub-detection images of each stripe mark.

[0155] Specifically, performing the imaging process on the plurality of stripe marks includes: performing a first imaging process on the first stripe mark 101; and performing a second imaging process on the second stripe mark 102.

[0156] Specifically, the first imaging process includes: incident light from the light-emitting device forming a first stripe spot 210 on the surface of the first stripe mark 101, the first stripe spot 210 and the first stripe mark 101 forming a first moiré fringe, the incident light forming a first signal light after passing through the first stripe mark 101; collecting the first signal light through the imaging device, and obtaining a first sub-detection image of the first stripe mark 101 based on the collected first signal light.

[0157] The second imaging process includes: incident light from the light-emitting device forming a second stripe spot 220 on the surface of the second stripe mark 102, the second stripe spot 220 forming a second moiré fringe with the second stripe mark 102, the incident light forming a second signal light after passing through the second stripe mark 102, the second signal light carrying information of the second moiré fringe; collecting the second signal light through the imaging device, and obtaining a second sub-detection image of the second stripe mark 102 based on the collected second signal light.

[0158] Both the first detection image and the second detection image include the first sub-detection image and the second sub-detection image.

[0159] Specifically, in Figure 4a In the embodiment shown, after acquiring the first sub-detection image, a second stripe light spot 220 is formed on the surface of the second stripe mark 102 by a light-emitting device.

[0160] Specifically, after acquiring the first sub-detection image, a second patterned light spot is formed on the surface of the second stripe mark 101 by adjusting the shaping element.

[0161] exist Figure 4b and 4cIn the illustrated embodiment, the pattern markings include a first pattern marking and a second pattern marking; both the first pattern marking and the second pattern marking include a first stripe marking 101 and a second stripe marking 102.

[0162] The patterned light spot includes a first stripe light spot and a second stripe light spot, and the patterned mark includes a first stripe mark and a second stripe mark. The first stripe light spot can form a first moiré fringe with the first stripe mark, and the first included angle is an acute angle or a right angle. The second stripe mark and the second stripe light spot form a second moiré fringe, and the second included angle is an acute angle or a right angle. The offset of the patterned mark along the first detection direction and the second detection direction can be obtained through the first moiré fringe and the second moiré fringe.

[0163] exist Figure 4b and 4c In the embodiment shown, after the first stripe spot 210 is formed on the surface of the first stripe mark 101 and the second stripe spot 220 is formed on the surface of the second stripe mark 102 by the light-emitting device, the first sub-detection image and the second sub-detection image are acquired by the imaging device.

[0164] Execute step S3 to obtain the moiré offset along the detection direction between the moiré stripes of the first pattern mark and the moiré stripes of the second pattern mark based on the first detection image and the second detection image.

[0165] The detection direction is perpendicular to or has an acute angle with the extension direction of the stripes in the pattern marking.

[0166] The step of obtaining the moiré offset along the detection direction between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark based on the first detection image and the second detection image includes: obtaining a first center position of the moiré fringes of the first pattern mark based on the first detection image; obtaining a second center position of the moiré fringes of the second pattern mark based on the second detection image; and obtaining the moiré offset based on the first center position and the second center position.

[0167] Specifically, obtaining the first center position of the moiré fringe of the first pattern mark based on the first detection image includes: obtaining the grayscale curve of the moiré fringe image in the first detection image along the detection direction; fitting the grayscale curve to obtain the first center position;

[0168] Obtaining the second center position of the moiré fringe of the second pattern mark based on the second detection image includes: obtaining the grayscale curve of the moiré fringe image in the second detection image along the detection direction; fitting the grayscale curve to obtain the second center position.

[0169] In this embodiment, both the first detection image and the second detection image include a first sub-detection image and a second sub-detection image;

[0170] The step of obtaining the moiré offset between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark based on the first detection image and the second detection image includes: obtaining a first offset between the first moiré fringes of the first pattern mark and the first moiré fringes of the second pattern mark along a first detection direction based on a first sub-detection image of the first detection image and a first sub-detection image of the second detection image; obtaining a second offset between the second moiré fringes of the first pattern mark and the second moiré fringes of the second pattern mark along a second detection direction based on a second sub-detection image of the first detection image and a second sub-detection image of the second detection image; wherein the first detection direction and the second detection direction are perpendicular or have an acute angle between them.

[0171] The first detection direction is perpendicular to or has an acute angle with the extension direction of the first stripe mark; the second detection direction is perpendicular to or has an acute angle with the extension direction of the second stripe mark.

[0172] Step S4 is executed to obtain the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image. The detection magnification is the ratio of the feature parameters of the moiré fringe to the feature parameters of the fringe markers. The feature parameters are spatial frequency or period.

[0173] Because moiré fringes have a low spatial frequency, the imaging device can image moiré fringes but has difficulty imaging the high-frequency signals of the fringe markings. Therefore, the first detection image includes an image of moiré fringes with a first pattern marking; the first detection image also includes an image of moiré fringes with a second pattern marking.

[0174] The spatial filter, located at the Fourier plane of the collecting device, filters the signal light collected by the collecting device, removing lower-frequency components. The edges of the pattern markings contain high-frequency signals, while the background of the object under test is often a low-frequency signal. The spatial filter removes the lower-frequency components of the signal light, reducing interference signals from the background of the object under test without filtering out moiré fringe information. Therefore, the detection device can improve the contrast of the formed pattern and increase detection accuracy.

[0175] The detection magnification in the detection direction is obtained based on one or a combination of the first detection image and the second detection image. The detection magnification represents the ratio of the spatial frequency of the moiré fringe to the spatial frequency of the fringe mark. The method includes: obtaining a first feature parameter of the moiré fringe image of the first pattern mark along the detection direction based on the first detection image, wherein the first feature parameter is a spatial frequency or period; and obtaining the detection magnification based on the ratio of the first feature parameter to the first feature parameter of the fringe mark in the first pattern mark.

[0176] Specifically, obtaining the detection magnification based on the ratio of the first feature parameter of the first pattern mark to the first feature parameter of the stripe mark in the first pattern mark includes:

[0177] When the first feature parameter is spatial frequency, the detection magnification is: n = ν2 / ν1, where n is the detection magnification, ν2 is the spatial frequency of the stripe mark in the first pattern mark, and ν1 is the spatial frequency of the moiré fringe of the first pattern mark. When the first feature parameter is periodicity, the detection magnification is: n = d1 / d2, where n is the detection magnification, d2 is the period of the stripe mark in the first pattern mark, and d1 is the period of the moiré fringe of the first pattern mark.

[0178] Alternatively, the detection magnification is: n = ν1 / ν2, where n is the detection magnification, ν2 is the spatial frequency of the stripe mark in the first pattern mark, and ν1 is the spatial frequency of the moiré fringe of the first pattern mark; or, the detection magnification is: n = d2 / d1, where n is the detection magnification, d2 is the period of the stripe mark in the first pattern mark, and d1 is the period of the moiré fringe of the first pattern mark.

[0179] In other embodiments, the step of obtaining the detection magnification in the detection direction based on one or a combination of the first and second detection images includes: obtaining a second feature parameter of the moiré fringe image of the second pattern mark along the detection direction based on the second detection image, wherein the second feature parameter is a spatial frequency or period; and obtaining the detection magnification based on the ratio of the second feature parameter to the second feature parameter of the fringe mark in the second pattern mark. Since the extension direction and period of the corresponding fringe marks in the first and second pattern marks are the same, the magnification factor of the moiré fringes of the first detection image relative to the fringe mark of the first pattern mark is equal to the magnification factor of the moiré fringes of the second detection image relative to the fringe mark of the second pattern mark.

[0180] However, due to detection errors or process errors, the detection magnification obtained from the first detection image may differ from the detection magnification obtained from the second detection image. In another embodiment, the step of obtaining the detection magnification in the detection direction based on one or a combination of the first and second detection images includes: obtaining a first detection magnification of the first detection image in the detection direction based on the first detection image; obtaining a second detection magnification of the second detection image in the detection direction based on the second detection image; and obtaining the average of the first and second detection magnifications to obtain the detection magnification.

[0181] The pattern markings include: a first stripe marking and a second stripe marking. Both the first detection image and the second detection image include a first sub-detection image and a second sub-detection image.

[0182] The detection method includes repeatedly obtaining the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image, until a first detection magnification along the first detection direction and a second detection magnification along the second detection direction are obtained.

[0183] The step of repeatedly obtaining the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image includes: obtaining a first detection magnification of the detection image in the first detection direction based on one or a combination of the first sub-detection images of the first detection image and the second detection image; and obtaining a second detection magnification of the detection image in the second detection direction based on one or a combination of the second sub-detection images of the first detection image and the second detection image.

[0184] In the embodiments provided by the present invention, the first detection image and the second detection image are the same image, and the first detection processing and the second detection processing are the same detection process. That is, the image of the object to be tested can be obtained by performing an imaging processing on the object to be tested once. The image of the object to be tested includes the first detection image and the second detection image; or the first detection image and the second detection image are different images, and the first detection image and the second detection image are obtained by different first detection processing and second detection processing, respectively.

[0185] Execute step S5 to obtain the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification.

[0186] Specifically, when the detection magnification is: n = ν2 / ν1, where n is the detection magnification, ν2 is the spatial frequency of the stripe mark in the first pattern mark, and ν1 is the spatial frequency of the moiré fringe of the first pattern mark; or, when the detection magnification is: n = d1 / d2, where n is the detection magnification, d2 is the period of the stripe mark in the first pattern mark, and d1 is the period of the moiré fringe of the first pattern mark, the step of obtaining the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification includes: obtaining the ratio of the moiré offset to the detection magnification to obtain the alignment error.

[0187] When the detection magnification is: n = ν1 / ν2, where n is the detection magnification, ν2 is the spatial frequency of the stripe mark in the first pattern mark, and ν1 is the spatial frequency of the moiré fringe of the first pattern mark; or, when the detection magnification is: n = d2 / d1, where n is the detection magnification, d2 is the period of the stripe mark in the first pattern mark, and d1 is the period of the moiré fringe of the first pattern mark, the step of obtaining the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification includes: obtaining the product of the moiré offset and the detection magnification to obtain the alignment error.

[0188] Specifically, the feature parameter is the period, and the alignment error between the first pattern mark and the second pattern mark is obtained based on the ratio of the moiré offset to the detection magnification; or, the feature parameter is the spatial frequency, and the alignment error between the first pattern mark and the second pattern mark is obtained based on the product of the moiré offset and the detection magnification.

[0189] Specifically, in this embodiment, the first pattern mark includes a first stripe mark 101 and a second stripe mark 102. The imaging device is used to form a first stripe spot 210 and a second stripe spot 220. The first stripe mark 101 and the first stripe spot 210 form a first moiré fringe; the second stripe mark 101 and the second stripe spot 220 form a second moiré fringe. Both the first detection image and the second detection image include images of the first moiré fringe and the second moiré fringe.

[0190] The detection method includes: performing the following steps on a first moiré fringe: obtaining a moiré offset between the moiré fringe of the first pattern mark and the moiré fringe of the second pattern mark based on the first detection image and the second detection image; obtaining an alignment error between the first pattern mark and the second pattern mark based on the moiré offset and the detection magnification; and obtaining an alignment error between the first pattern mark and the second pattern mark along a first detection direction. Then, performing the following steps on a second moiré fringe: obtaining a moiré offset between the moiré fringe of the first pattern mark and the moiré fringe of the second pattern mark based on the first detection image and the second detection image; obtaining an alignment error between the first pattern mark and the second pattern mark based on the moiré offset and the detection magnification; and obtaining an alignment error between the first pattern mark and the second pattern mark along a second detection direction.

[0191] Specifically, the step of repeatedly obtaining the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification includes: obtaining the alignment error between the first pattern mark and the second pattern mark along the first detection direction based on the first moiré offset and the first detection magnification; and obtaining the alignment error between the first pattern mark and the second pattern mark along the second detection direction based on the second moiré offset and the second detection magnification.

[0192] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A testing device, characterized in that, Includes a light-emitting device, a collection device, a spatial filter, and a detection component; A light-emitting device is used to generate incident light that illuminates a test object. The test object has a pattern mark on its surface. The pattern mark includes a stripe mark. The stripe mark includes multiple stripes arranged repeatedly in the same direction. The incident light passes through the pattern mark to form signal light carrying moiré fringe information. The angle between the stripe extension directions of the two stripe structures used to form the moiré fringe is an acute angle or a right angle. A collecting device is used to collect the signal light and propagate it to the spatial filter; wherein the central axis of the collected signal light has a non-zero angle with the central axis of the incident light; the signal light collected by the collecting device is the signal light formed by the scattering of the incident light by the test object, and the signal light does not contain the reflected light of the incident light; The spatial filter is located at the Fourier plane of the collecting device and is used to filter the signal light collected by the collecting device, remove the lower frequency components in the signal light, and reduce the interference signal generated by the background of the object under test. The detection component is used to image the moiré fringes based on the signal light filtered by the spatial filter, thereby forming a detection image.

2. The detection device according to claim 1, characterized in that, The incident light is used to form a patterned light spot on the surface of the patterned mark. The patterned light spot includes a striped light spot, which includes a plurality of stripes arranged repeatedly in the same direction. The striped light spot and the striped mark form the moiré stripe. Alternatively, the pattern markings include a plurality of stripe markings, among which there are a first overlapping stripe marking and a second overlapping stripe marking, the first overlapping stripe marking and the second overlapping stripe marking at least partially overlap, the first overlapping stripe marking and the second overlapping stripe marking forming the moiré stripe.

3. The detection device according to claim 1, characterized in that, The detection device also includes a tube mirror, which is used to converge mutually parallel signal light after being filtered by the spatial filter to the same point of the detection component, and to converge signal light propagating in different directions to different points of the detection component; The detection component is located at the focal plane of the endoscope.

4. The detection device according to claim 1, characterized in that, The incident light is incident on the surface of the object to be tested from outside the collection device; The detection device further includes a beam splitter for directing the incident light toward the collecting device, which in turn collects the incident light and directs it to the surface of the object under test. The beam splitter also reflects the incident light onto the surface of the object under test and transmits the signal light collected by the collecting device, or transmits the incident light onto the surface of the object under test and reflects the signal light collected by the collecting device. The spatial filter is located in the optical path between the beam splitter and the collecting device, or the spatial filter is located in the optical path between the beam splitter and the detection component.

5. The detection device according to claim 1, characterized in that, The light-emitting device includes one or more light-emitting components, each light-emitting component including a light source and a shaping component. The light source is used to emit an initial light beam; the shaping component is used to shape the initial light beam to form the incident light. Alternatively, the light-emitting component includes a display screen having a display pattern, and projects the display pattern onto the surface of the object under test to form a patterned light spot; The extension direction of the stripes and the period of the striped light spot, or both, can be adjusted.

6. The detection device according to claim 1, characterized in that, The spatial filter includes a light-shielding plate used to block the lower frequency components of the signal light; the center of the light-shielding plate coincides with the central axis of the beam passing through the spatial filter.

7. The detection device according to claim 6, characterized in that, The light-shielding plate is used to block light levels from -3 to +3, and the light-shielding plate is circular, square, or regular hexagonal.

8. The detection device according to claim 6, characterized in that, The spatial filter further includes: a mounting component for mounting the light-shielding sheet, the mounting component transmitting the higher frequency components of the signal light; a base fixedly connected to the mounting component; the mounting component of the spatial filter is a light-transmitting substrate, the light-shielding sheet is formed by coating the light-transmitting substrate with a light-shielding material, and the light-transmitting substrates of the mounting component and the light-shielding sheet are made of the same material.

9. The detection device according to claim 1, characterized in that, The pattern marking includes multiple stripe markings, among which there are a first stripe marking and a second stripe marking. The extension directions of the stripes in the first stripe marking and the second stripe marking have a first included angle, which is a right angle or an acute angle. The incident light is used to form a patterned light spot on the surface of the patterned mark. The patterned light spot includes striped light spots, and the patterned light spot includes multiple striped light spots, including a first striped light spot and a second striped light spot. The extension directions of the stripes in the first striped light spot and the second striped light spot have a second included angle, which is a right angle or an acute angle. The first striped light spot is used to form a first moiré fringe with the first striped mark, and the second striped light spot is used to form a second moiré fringe with the second striped mark. The detection image includes an image of the first moiré fringe and an image of the second moiré fringe. The second included angle is the same as the first included angle.

10. The detection device according to claim 1, characterized in that, The test object includes multiple pattern marks located in different film layers, and the multiple pattern marks include a first pattern mark and a second pattern mark; The detection device also includes a control device for controlling the light-emitting device and the imaging device to acquire detection images of the first pattern mark and the second pattern mark; The processing module includes: a moiré offset acquisition unit, used to acquire the moiré offset in the detection direction between the moiré stripes of the first pattern mark and the moiré stripes of the second pattern mark based on the first detection image and the second detection image; The detection magnification acquisition unit is used to acquire the detection magnification of the detection image in the detection direction based on one or a combination of the first detection image and the second detection image, wherein the detection magnification is the ratio of the feature parameter of the moiré fringe to the feature parameter of the fringe mark, and the feature parameter is spatial frequency or period; the alignment error acquisition unit is used to acquire the alignment error between the first pattern mark and the second pattern mark along the detection direction based on the moiré offset and the detection magnification.

11. A detection method based on the detection equipment according to any one of claims 1 to 10, characterized in that, This includes performing detection processing on pattern markings to obtain detection images; The detection process includes: generating incident light that illuminates the test object through the light-emitting device; the test object has a pattern mark on its surface; the pattern mark includes a stripe mark; the stripe mark includes multiple stripes arranged repeatedly in the same direction; and the incident light forms a signal light carrying moiré fringe information after passing through the pattern mark. The signal light is collected by the collection device and then propagated to the spatial filter. The spatial filter is used to filter the signal light from the collection device, removing the lower frequency components from the signal light. The detection component images the moiré fringes based on the signal light filtered by the spatial filter, forming a detection image.

12. The detection method according to claim 11, characterized in that, The step of generating incident light illuminating a test object through the light-emitting device, wherein the test object has a pattern mark on its surface, the pattern mark including a stripe mark, the stripe mark including multiple stripes arranged repeatedly in the same direction, and the incident light forming a signal light carrying moiré fringe information after passing through the pattern mark includes: generating incident light through the light-emitting device, the incident light forming a pattern light spot on the surface of the pattern mark, the pattern light spot including a stripe light spot, the stripe light spot including multiple stripes arranged repeatedly in the same direction, the stripe light spot and the stripe mark forming a moiré fringe, the incident light forming a signal light after passing through the test object, and the signal light carrying the information of the moiré fringe.

13. The detection method according to claim 11, characterized in that, The pattern markings include multiple stripe markings, among which there are first overlapping stripe markings and second overlapping stripe markings, the first overlapping stripe markings and the second overlapping stripe markings at least partially overlap, and the first overlapping stripe markings and the second overlapping stripe markings form moiré stripes; The step of generating incident light that illuminates the test object through the light-emitting device, wherein the test object has a pattern mark, the pattern mark includes a stripe mark, the stripe mark includes multiple stripes arranged repeatedly in the same direction, and the incident light forms a signal light carrying moiré fringe information after passing through the pattern mark includes: generating incident light through the light-emitting device, the incident light illuminating the overlapping portion of the first overlapping stripe mark and the second overlapping stripe mark, the incident light forming a signal light after passing through the first overlapping stripe mark and the second overlapping stripe mark, the signal light carrying the information of the moiré fringe.

14. The detection method according to claim 11, characterized in that, The test object includes multiple pattern marks located in different film layers, and the multiple pattern marks include a first pattern mark and a second pattern mark; The detection method further includes: performing a first detection process on the first pattern mark to obtain a first detection image of the first pattern mark; performing a second detection process on the second pattern mark to obtain a second detection image of the second pattern mark; obtaining a moiré offset along the detection direction between the moiré fringes of the first pattern mark and the moiré fringes of the second pattern mark based on the first detection image and the second detection image; obtaining a detection magnification of the detection image along the detection direction based on one or a combination of the first detection image and the second detection image, wherein the detection magnification is the ratio of the feature parameters of the moiré fringes to the feature parameters of the fringe mark, the feature parameters including spatial frequency or period; and obtaining an alignment error along the detection direction between the first pattern mark and the second pattern mark based on the moiré offset and the detection magnification.

Images