Detection device and detection method thereof

Abstract

The application provides a detection device, which comprises a light emitting device for generating incident light for irradiating a to-be-detected object, wherein the to-be-detected object has a pattern mark on the surface, the pattern mark comprises a stripe mark, the incident light is used for forming a pattern spot on the surface of the pattern mark, the pattern spot comprises a stripe spot, the stripe spot is used for forming a moire fringe with the stripe mark, the incident light forms signal light after passing through the pattern mark, the signal light carries information of the moire fringe, the stripe extending direction of the stripe spot and the stripe extending direction of the stripe mark have a preset angle, and the preset angle is an acute angle; and an imaging device is used for collecting the signal light and forming a detection image according to the collected signal light. The detection device can increase detection precision and improve adjustability.

Description

TECHNICAL FIELD

[0001] The present application relates to a device applied to semiconductor manufacturing process, in particular to a detection device for detecting production quality of semiconductor devices and a detection method thereof. BACKGROUND

[0002] With the development of semiconductor industry, the critical dimension of semiconductor devices is gradually reduced, and small production errors may also cause the failure of semiconductor devices in semiconductor manufacturing process, which puts forward higher requirements for semiconductor detection system.

[0003] The production process of semiconductor devices includes: depositing a plurality of stacked film layers on a silicon substrate one by one, and forming different patterns in each film layer by etching. In the process of etching the film layer to form the pattern, the positions of the patterns of the upper and lower film layers must meet the overlay requirement. In order to monitor the relative position relationship between the upper and lower film layers, an overlay mark is formed in the film layer of the cutting track area while etching the film layer. By overlay measurement of the overlay mark, the alignment error of the upper and lower patterns is determined, so as to monitor the semiconductor manufacturing process.

[0004] In the prior art, the overlay measurement methods include: imaging-based optical measurement method (IBO), diffraction-based optical measurement method (DBO) and Moire fringe-based measurement method. Since the detection method based on Moire fringe can convert the alignment error of small space period overlay mark into the alignment error of large space period Moire fringe, the detection precision can be improved. However, with the improvement of the integration of semiconductor devices, the size of the overlay mark is gradually reduced, and the detection method of Moire fringe gradually shows its advantages.

[0005] However, the detection precision of the traditional detection device based on Moire fringe is low, and the adjustment ability is poor, which cannot meet different detection requirements. SUMMARY

[0006] To solve the above problems, the present application provides a detection device and a detection method thereof, which can improve the detection precision by forming a pattern light spot on the surface of the measured object through the light emitting device, and can flexibly adjust the included angle between the stripe light spot and the stripe mark by making the stripe extension direction of the stripe light spot and the stripe extension direction of the stripe mark have an acute included angle, so as to adjust the period and the number of Moire fringes formed.

[0007] The technical scheme of the present application provides a detection device, characterized in that comprising: a light emitting device for generating incident light irradiating a to-be-detected object, the to-be-detected object surface having a pattern mark, the pattern mark comprising a stripe mark, the stripe mark comprising a plurality of stripes arranged repeatedly in the same direction, the incident light being used to form a pattern spot on the surface of the pattern mark, the pattern spot comprising a stripe spot, the stripe spot comprising a plurality of stripes arranged repeatedly in the same direction, the stripe spot being used to form a Moire fringe with the stripe mark, the incident light forming a signal light after passing through the pattern mark, the signal light carrying information of the Moire fringe, the stripe extending direction of the stripe spot and the stripe extending direction of the stripe mark having a preset angle, the preset angle being an acute angle; an imaging device for collecting the signal light and forming a detection image according to the collected signal light.

[0008] Optionally, the imaging device comprises: an objective lens for collecting the signal light; and a detection assembly for forming the detection image according to the signal light collected by the objective lens.

[0009] The incident light is incident on the surface of the to-be-detected object from outside the objective lens; or the detection device further comprises a beam splitter for making the incident light propagate toward the objective lens, the objective lens being further used to collect the incident light and make the incident light reach the surface of the to-be-detected object; and the beam splitter is further used to split the signal light collected by the objective lens from the incident light and make the signal light propagate toward the detector.

[0010] Optionally, the light emitting device comprises one or more light emitting assemblies, each of the light emitting assemblies comprising: a light source for emitting an initial light beam; and a shaping assembly for shaping the initial light beam to form the incident light, the incident light being used to form the pattern spot on the surface of the to-be-detected object; or the light emitting assembly comprises a display screen having a display pattern, and the display screen is used to project the display pattern to the surface of the to-be-detected object to form the pattern spot.

[0011] One or both of the stripe extending direction in the stripe spot and the period of the stripe spot are adjustable.

[0012] Optionally, the shaping assembly is configured to rotate around an optical axis of the shaping assembly; or the light emitting device is configured to rotate around an optical axis of the light emitting device.

[0013] Optionally, the pattern mark comprises a plurality of stripe marks, the plurality of stripe marks comprising a first stripe mark and a second stripe mark, the first stripe mark and the second stripe mark having a first included angle between the stripe extending directions of the stripes in the first stripe mark and the second stripe mark, the first included angle being a right angle or an acute angle.

[0014] The pattern light spot comprises a plurality of stripe light spots, the plurality of stripe light spots comprise a first stripe light spot and a second stripe light spot, the first stripe light spot and the second stripe light spot have a second included angle between the extension directions of the stripes, and the second included angle is a right angle or an acute angle; the first stripe light spot is used to form a first Moiré fringe with the first stripe mark, and the second stripe light spot is used to form a second Moiré fringe with the second stripe mark; the detection image comprises an image of the first Moiré fringe and an image of the second Moiré fringe; and the second included angle is the same as the first included angle.

[0015] Optionally, the period of the stripe light spot is the same as or different from that of the stripe mark; and the included angle between the extension direction of the stripe in the stripe light spot and the extension direction of the stripe in the stripe mark is 1°-30°.

[0016] Optionally, the object to be detected comprises a plurality of pattern marks respectively located in different film layers, the plurality of pattern marks comprise a first pattern mark and a second pattern mark; and the detection device further comprises a control device configured to control the light emitting device and the imaging device to acquire detection images of the first pattern mark and the second pattern mark.

[0017] The processing module comprises: a Moiré offset acquisition unit configured to acquire a Moiré offset between the Moiré fringe of the first pattern mark and the Moiré fringe of the second pattern mark in the detection direction according to the first detection image and the second detection image; a detection magnification acquisition unit configured to acquire a detection magnification of the detection image in the detection direction according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the Moiré fringe to a characteristic parameter of the stripe mark, the characteristic parameter being a spatial frequency or a period; and an alignment error acquisition unit configured to acquire an alignment error between the first pattern mark and the second pattern mark in the detection direction according to the Moiré offset and the detection magnification.

[0018] Optionally, the characteristic parameter is a period, and the alignment error acquisition unit is configured to acquire the alignment error between the first pattern mark and the second pattern mark according to a ratio of the Moiré offset to the detection magnification; or the characteristic parameter is a spatial frequency, and the alignment error acquisition unit is configured to acquire the alignment error between the first pattern mark and the second pattern mark according to a product of the Moiré offset and the detection magnification.

[0019] A detection method based on the above-mentioned detection device, comprising: performing a detection process on a pattern light spot to acquire a detection image of the pattern light spot; the pattern light spot comprises a stripe light spot, the stripe light spot comprises a plurality of stripes arranged repeatedly in the same direction, the pattern mark comprises a stripe mark, and the stripe mark comprises a plurality of stripes arranged repeatedly in the same direction; and the detection image comprises a sub-detection image of the stripe mark.

[0020] The step of the detection processing includes: performing imaging processing on the fringe mark to obtain a sub-detection image of the fringe mark;

[0021] The step of performing the imaging processing on the fringe mark includes: forming a fringe light spot on the fringe mark surface by the incident light of the light emitting device, the fringe light spot and the fringe mark form a Moire fringe, the incident light forms a signal light after passing through the fringe mark, the signal light carries information of the Moire fringe, the fringe extension direction of the fringe light spot and the fringe extension direction of the fringe mark have a preset included angle, the preset included angle is an acute angle; collecting the signal light by the imaging device, and forming a sub-detection image according to the collected signal light.

[0022] Optionally, the object to be detected includes a plurality of pattern marks respectively located in different film layers, the plurality of pattern marks include a first pattern mark and a second pattern mark;

[0023] The detection method further includes: performing first detection processing on the first pattern mark to obtain a first detection image of the first pattern mark; performing second detection processing on the second pattern mark to obtain a second detection image of the second pattern mark; obtaining a Moire shift between the Moire fringe of the first pattern mark and the Moire fringe of the second pattern mark in a detection direction according to the first detection image and the second detection image; obtaining a detection magnification of the detection image in the detection direction according to one or a combination of both of the first detection image and the second detection image, the detection magnification is a ratio of a characteristic parameter of the Moire fringe to a characteristic parameter of the fringe mark, the characteristic parameter includes a spatial frequency or a period; obtaining an alignment error between the first pattern mark and the second pattern mark in the detection direction according to the Moire shift and the detection magnification.

[0024] Optionally, the pattern mark includes a plurality of fringe marks, the plurality of fringe marks include a first fringe mark and a second fringe mark, the first fringe mark and the second fringe mark have a first included angle between the extension directions of the fringes, the first included angle is a right angle or an acute angle; the pattern light spot includes a first fringe light spot and a second fringe light spot, the first fringe light spot and the second fringe light spot have a second included angle between the extension directions of the fringes, the second included angle is a right angle or an acute angle;

[0025] The step of performing the detection processing on the pattern mark includes: performing first imaging processing on the first fringe mark; performing second imaging processing on the second fringe mark;

[0026] The first imaging process comprises: forming a first fringe spot on the first fringe mark surface by incident light of a light emitting device, the first fringe spot and the first fringe mark forming a first Moiré fringe, the incident light forming a first signal light after passing through the first fringe mark, the first signal light carrying information of the first Moiré fringe; collecting the first signal light by the imaging device, and obtaining a first sub-detection image of the first fringe mark according to the collected first signal light.

[0027] The second imaging process comprises: forming a second fringe spot on the second fringe mark surface by incident light of a light emitting device, the second fringe spot and the second fringe mark forming a second Moiré fringe, the incident light forming a second signal light after passing through the second fringe mark, the second signal light carrying information of the second Moiré fringe; collecting the second signal light by the imaging device, and obtaining a second sub-detection image of the second fringe mark according to the collected second signal light.

[0028] Optionally, the first included angle is the same as the second included angle.

[0029] Optionally, the first detection image and the second detection image each comprise a first sub-detection image and a second sub-detection image.

[0030] The step of obtaining the Moiré shift between the Moiré fringes of the first pattern mark and the Moiré fringes of the second pattern mark according to the first detection image and the second detection image comprises: obtaining a first shift between the first Moiré fringe of the first pattern mark and the first Moiré fringe of the second pattern mark along a first detection direction according to the first sub-detection image of the first detection image and the first sub-detection image of the second detection image; obtaining a second shift between the second Moiré fringe of the first pattern mark and the second Moiré fringe of the second pattern mark along a second detection direction according to the second sub-detection image of the first detection image and the second sub-detection image of the second detection image; the first detection direction and the second detection direction are perpendicular or have an acute included angle.

[0031] Optionally, after obtaining the first detection image, a second fringe spot is formed on the second fringe mark surface by a light emitting device; or, after forming the first fringe spot on the first fringe mark surface and the second fringe spot on the second fringe mark surface by the light emitting device, the first sub-detection image and the second sub-detection image are obtained by the imaging device.

[0032] The technical scheme of the present application provides a detection device. The light emitting device forms a stripe light spot on the stripe mark surface. The preset angle between the stripe light spot and the stripe mark is an acute angle. The preset angle can be set by the light emitting device. The Moire fringe is formed by the stripe light spot and the stripe mark. The preset angle between the stripe light spot and the stripe mark can be easily adjusted by the light emitting device. The Moire fringe period and the period number can be adjusted. The detection device can meet different requirements. In addition, the period number of the Moire fringe (i.e. the number of bright stripes / dark stripes in the same volume) increases with the increase of the preset angle in the same volume. Therefore, the preset angle can not be zero. The preset angle is an acute angle. The Moire fringe period number can be increased. The fitting accuracy can be improved. The accuracy of the detection device can be improved.

[0033] Further, the pattern light spot includes a first stripe light spot and a second stripe light spot. The pattern mark includes a first stripe mark and a second stripe mark. The first stripe light spot can form a first Moire fringe with the first stripe mark. The first included angle is an acute angle or a right angle. The second stripe mark forms a second Moire fringe with the second stripe light spot. The second included angle is an acute angle. The displacement of the pattern mark in two directions can be obtained by the first Moire fringe and the second Moire fringe. The detectable parameters can be increased.

[0034] Further, the light emitting device includes a plurality of light emitting components. The first stripe light spot and the second stripe light spot can be formed on the pattern mark surface by different light emitting components. The first Moire fringe and the second Moire fringe can be adjusted to the best state. BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application will be described in detail below with reference to the accompanying drawings and embodiments. The advantages and implementation modes of the present application will be more obvious. The contents shown in the drawings are only used to explain and describe the present application, and do not constitute any limitation on the present application. The drawings are only schematic and are not strictly drawn to scale. In the drawings:

[0036] Figure 1 The structure schematic diagram of the first embodiment of the detection device according to the present application is shown;

[0037] Figure 2 The structure schematic diagram of the pattern mark on the surface of the object to be detected according to the present application is shown;

[0038] Figure 3 The principle diagram of the Moire fringe formed by the detection device of the technical scheme of the present application is shown;

[0039] Figures 4a to 4cFig. 1 shows a structural diagram of a pattern spot according to an embodiment of the detection device of the present application;

[0040] Figure 5 Fig. 2 shows a structural diagram of a second embodiment of the detection device of the present application;

[0041] Figure 6 Fig. 3 shows a structural diagram of a third embodiment of the detection device of the present application;

[0042] Figure 7 Fig. 4 shows a structural diagram of a fourth embodiment of the detection device of the present application;

[0043] Figure 8 Fig. 5 shows a structural diagram of a fifth embodiment of the detection device of the present application;

[0044] Figure 9 Fig. 6 shows a flow diagram of the imaging process in an embodiment of the detection method of the detection device of the present application;

[0045] Figure 10 Fig. 7 shows a flow diagram of the imaging process in an embodiment of the detection method of the detection device of the present application. DETAILED DESCRIPTION

[0046] In the prior detection device for detecting an object by using a Moiré fringe, the object includes a test mark and a standard mark, the test mark and the standard mark are used to form a Moiré fringe; the detection device includes a light source for emitting a probe light to the surface of the object, the probe light forms a signal light after passing through the test mark and the standard mark, the signal light carries the information of the Moiré fringe; a detector is used to acquire the signal light and form an image of the Moiré fringe according to the signal light.

[0047] In the prior detection device for detecting an object by using a Moiré fringe, the object includes a test mark and a standard mark, the test mark and the standard mark are used to form a Moiré fringe; the detection device includes a light source for emitting a probe light to the surface of the object, the probe light forms a signal light after passing through the test mark and the standard mark, the signal light carries the information of the Moiré fringe; a detector is used to acquire the signal light and form an image of the Moiré fringe according to the signal light.

[0048] The technical scheme of the present application provides an optical device, comprising: a light emitting device for generating incident light irradiating a to-be-measured object, the to-be-measured object surface having a pattern mark, the pattern mark comprising a stripe mark, the incident light being used to form a pattern spot on the pattern mark surface, the pattern spot being used to form a Moire fringe with the pattern mark, the incident light forming a signal light after passing through the pattern mark, the pattern spot comprising a stripe spot, the stripe direction of the stripe spot having a preset angle with the stripe direction of the stripe mark, the preset angle being an acute angle; and an imaging device for collecting the signal light and forming a detection image according to the collected signal light. The detection device can increase the period and the number of Moire fringes, thereby adapting to different requirements.

[0049] The technical scheme provided by the present application will be described in detail below in combination with embodiments.

[0050] One or more specific embodiments of the present application will be described below. To be devoted to providing a brief description of these embodiments, all the features of the actual implementation can not 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 implementation-specific decisions must be made to achieve the specific goals of the developer, such as compliance with system-related and business-related constraints, which can vary from one implementation to another. In addition, it should be understood that such development efforts can be complex and time-consuming, but would be merely routine work for those of ordinary skill in the art with the benefit of the present disclosure. Figure 1 is a structural schematic diagram of an embodiment of the detection device of the present application;

[0051] Figure 2 is a structural schematic diagram of the pattern mark of the technical scheme of the present application;

[0052] Figure 3 is a principle diagram of the detection device provided by the technical scheme of the present application forming a Moire fringe;

[0053] Figures 4a to 4c shows the structural schematic diagram of each embodiment of the pattern spot formed by the detection device according to the present application.

[0054] Please refer to Figures 1 to 4cThe detection equipment provided by the technical scheme comprises: a light emitting device, which is used to generate incident light for irradiating a to-be-detected object 100, the to-be-detected object 100 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, the incident light is used to form a pattern light spot 200 on the surface of the pattern mark, the pattern light spot 200 comprises a stripe light spot, the stripe light spot comprises a plurality of stripes arranged repeatedly in the same direction, the extension direction of the stripe of the stripe light spot has a preset angle with the extension direction of the stripe of the stripe mark, and 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 forms signal light after passing through the pattern mark, and the signal light carries information of the Moiré fringe; and an imaging device is used to collect the signal light and form a detection image according to the collected signal light.

[0055] The stripe light spot is formed on the surface of the stripe mark by the light emitting device, the preset angle between the stripe light spot and the stripe mark is an acute angle, the preset angle can be set by the light emitting device, the Moiré fringe is formed by the stripe light spot and the stripe mark, the preset angle between the stripe light spot and the stripe mark can be adjusted by the light emitting device, the adjustability of the period and the number of the Moiré fringe can be increased, and thus various different requirements can be met. In addition, the number of periods of the Moiré fringe (that is, the number of bright stripes / dark stripes in the same volume) increases with the increase of the preset angle in the same volume, and thus the preset angle is an acute angle, the number of periods of the Moiré fringe is increased, the accuracy of subsequent fitting is improved, and thus the accuracy of the detection equipment is improved.

[0056] It should be noted that the included angle between the two directions in the technical scheme provided by the present application refers to the smaller included angle between the two directions, that is, the included angle between the two directions can only range from 0° to 90°.

[0057] In the embodiment, the light emitting device is used to form a stripe light spot on the surface of the to-be-detected object 100. The stripe light spot comprises a plurality of stripes arranged periodically. That is, the stripe light spot is a light spot in which bright stripes and dark stripes are arranged alternately.

[0058] The light emitting device comprises one or more light emitting components, the light emitting component comprises a light source 110 used to emit an initial light beam, and a shaping component 120 used to shape the initial light beam to form the incident light, and the incident light is used to form the pattern light spot 200 on the surface of the to-be-detected object 100. Alternatively, the light emitting component comprises a display screen, the display screen has a display pattern, and the display pattern is projected to the surface of the to-be-detected object 100 to form the pattern light spot 200.

[0059] In particular, the light emitting device includes one light emitting component in the embodiment. In another embodiment, the light emitting component includes a plurality of light emitting components (as shown in FIG. 4).

[0060] The shaping component 120 includes a diffractive optical element or a spatial modulator.

[0061] In the embodiment, the central axis of the signal light collected by the imaging device and the central axis of the incident light have a non-zero included angle.

[0062] The included angle between the central axes is the smaller included angle between the central axes.

[0063] The light emitting device is used for emitting incident light, and the incident light forms a pattern light spot 200 on the pattern mark surface, the pattern light spot 200 and the pattern mark form Moire fringes, and the detection accuracy can be improved by detecting the object 100 according to the image of the Moire fringes. At the same time, the central axis of the signal light collected by the imaging device and the central axis of the incident light have a non-zero included angle, so that the signal light collected by the imaging device is separated from the incident light, the part of the light emitting device for forming the pattern light spot 200 on the pattern mark surface is separated from the part of the imaging device for collecting the signal light, that is, the light emitting device for emitting the incident light does not need to be used for collecting the signal light, so that the design requirement of the light emitting device can be reduced.

[0064] In the embodiment, the imaging device includes an objective lens 130 for collecting the signal light, and 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 according to the signal light collected by the objective lens 130. That is, in the embodiment, the incident light does not pass through the objective lens 130, and the objective lens 130 is only used for collecting the signal light, so that the requirement for the objective lens 130 can be reduced.

[0065] In the embodiment, the imaging device further includes a converging lens group 140 for converging the light passing through the objective lens to the detection component 150.

[0066] In the embodiment, the incident angle of the central axis of the incident light and the exit angle of the central axis of the signal light are different; or the incident angle of the central axis of the incident light, the central axis of the signal light and the surface normal of the object 100 are not coplanar. That is, the signal light collected by the objective lens 130 is formed by scattering the incident light by the object 100, the imaging device is used for dark field detection of the object 100, and the objective lens 130 does not collect the reflected light of the incident light. The dark field detection of the object 100 by the imaging device can improve the contrast of the obtained image and improve the detection accuracy. In other embodiments, the central axis of the incident light and the central axis of the signal light are symmetrical about the surface normal of the object 100, so that the imaging system is as shown in FIG. 5. Figure 5The incident light is shown.

[0067] Specifically, in the embodiment, the incident angle of the central axis of the incident light is not the same as the exit angle of the central axis of the signal light, and the exit angle of the signal light is zero. In other embodiments, the incident angle of the central axis of the incident light is zero.

[0068] Figure 2 A structural diagram of a surface pattern mark of a test object according to the present application is shown.

[0069] Reference is made to Figure 2 The pattern mark includes a stripe mark, and the stripe mark includes a plurality of stripes arranged in the same direction.

[0070] Specifically, the pattern mark includes a plurality of stripe marks, and the plurality of stripe marks include a first stripe mark 101 and a second stripe mark 102, and the first stripe mark 101 and the second stripe mark 102 have a first included angle between the extension directions of the stripes. Specifically, in the embodiment, the first included angle is a right angle; in other embodiments, the first included angle is an acute angle.

[0071] In the embodiment, the number of the first stripe mark 101 and the second stripe mark 102 is two; and the four stripe marks have a center of symmetry.

[0072] The test object 100 includes a plurality of pattern marks located in different film layers respectively, and the plurality of pattern marks include a first pattern mark and a second pattern mark.

[0073] The first pattern mark and the second pattern mark each 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.

[0074] The extension directions of the stripes in the first stripe mark 101 of the first pattern mark and the second pattern mark are the same; and the extension directions of the stripes in the second stripe mark 102 of the first pattern mark and the second pattern mark are the same.

[0075] Specifically, reference is made to Figure 2 The first pattern mark includes a first stripe mark 101a and a second stripe mark 102a; and the second pattern mark includes a first stripe mark 101b and a second stripe mark 102b.

[0076] In other embodiments, the first pattern mark only includes a first stripe mark, and correspondingly, the second pattern mark includes a first stripe mark; or, the first pattern mark only includes a second stripe mark, and correspondingly, the second pattern mark includes a second stripe mark.

[0077] In this embodiment, the period of the fringe light spot is the same as that of the fringe mark. In other embodiments, the period of the fringe light spot is not the same as that of the fringe mark.

[0078] In this embodiment, the initial light beam emitted by the light source 110 is shaped by the shaping element to form the fringe light spot. The shaping element 120 includes a diffractive optical element or a spatial modulator. Alternatively, the light emitting device includes a display screen having a display pattern, and the display pattern is projected onto the surface of the object 100 to form the pattern light spot 200.

[0079] Figure 3 A schematic diagram showing the principle of the fringe light spot and the fringe mark forming Moire fringes according to an embodiment of the present application.

[0080] Please refer to Figure 3 According to the geometric relationship, we can obtain:

[0081]

[0082] wherein M is the period of the Moire fringes, k1 is the period of the fringe mark, k2 is the period of the fringe light spot, and θ is the preset angle.

[0083] The period refers to the distance between adjacent bright fringes or the distance between adjacent dark fringes.

[0084] In order to more intuitively display the relationship between M and θ, the above formula is simplified as:

[0085] When k1=k2=k and θ is small, M=k / θ.

[0086] From the above reasoning, it can be concluded that the larger the θ, the smaller the period of the Moire fringes. Therefore, when θ is too small, the period of the Moire fringes is too large, and the number of Moire fringes in a certain space is less, resulting in less information of the obtained Moire fringes image, thereby reducing the fitting accuracy and detection accuracy. In the technical solution of the present application, the preset angle is an acute angle, which can prevent the number of Moire fringes from being too small, thereby affecting the accuracy of subsequent fitting.

[0087] Figures 4a to 4c Structure schematic diagram of each embodiment of the pattern light spot 200 formed by the detection device of the present application.

[0088] The pattern light spot 200 includes a fringe light spot, and the fringe light spot includes a plurality of fringes arranged repeatedly in the same direction.

[0089] It should be noted that when the angle between the stripe light spot and the stripe extension direction of the stripe mark is too large, the period of the formed Moiré fringes is too small, thereby resulting in low position accuracy of the detected pattern mark; when the angle between the stripe light spot and the stripe extension direction of the stripe mark is too small, the period of the formed Moiré fringes is reduced when the same stripe mark area is formed, thereby reducing the accuracy of subsequent model fitting and further reducing the detection accuracy. Specifically, in the embodiment, the angle between the stripe light spot and the stripe extension direction of the stripe mark is 1° to 30°, for example, 5°, 10° or 15°. In other embodiments, the angle between the stripe light spot and the stripe extension direction of the stripe mark can be less than 1° or greater than 30°.

[0090] The technical scheme of the present application provides three different embodiments of the pattern light spot 200, and provides accurate measurement of stripe marks with different extension directions through different embodiments of the pattern light spot 200. In other embodiments, different stripe marks with different extension directions can be detected through the same stripe light spot; and / or, only one stripe light spot or two stripe light spots are used to form Moiré fringes with the same stripe mark, and the position of the stripe mark is obtained through the relationship between the period of the Moiré fringes and the period of the stripe light spot.

[0091] The extension direction of the stripe light spot is the extension direction of the stripe in the stripe light spot; and the extension direction of the stripe mark is the extension direction of the stripe in the stripe mark.

[0092] Figures 4a to 4c Structural schematic diagrams of three pattern light spots 200 formed by the light emitting device on the surface of the object 100 are shown respectively.

[0093] Please refer to Figure 4a In the first embodiment, the pattern light spot 200 includes one stripe light spot, i.e., the pattern light spot 200 only includes the first stripe light spot 210. That is, the light emitting device can only form one stripe light spot on the mark surface at a time.

[0094] In one embodiment, the light emitting device is used to form a plurality of pattern light spots 200, and each pattern light spot 200 includes one stripe light spot.

[0095] The light emitting device forms a plurality of pattern light spots 200 on the mark surface at different times, and Moiré fringes formed by each pattern light spot 200 and the stripe mark are obtained respectively. The stripe extension directions of the pattern light spots 200 formed at different times are different.

[0096] The shaping assembly 120 respectively forms the stripe patterns with different extending directions on the pattern mark surfaces. Specifically, when the shaping assembly 120 is a diffraction grating, the diffraction grating is rotated to respectively form the stripe patterns with different extending directions on the first stripe mark 101 and the second stripe mark 102. Alternatively, when the light emitting assembly includes a display screen, the display screen is changed to respectively form the stripe patterns with different extending directions on the first stripe mark 101 and the second stripe mark 102.

[0097] In the embodiment, the detection device further includes a control device for controlling the light emitting device and the imaging device to obtain the detection images of the first pattern mark 200 and the second pattern mark 200.

[0098] Reference Figure 4b In the second embodiment, the pattern light spot 200 includes a plurality of stripe light spots, and the pattern light spot 200 further includes a second stripe light spot 220. The plurality of stripe light spots include a first stripe light spot 210 and the second stripe light spot 220. That is, the light emitting device can simultaneously form the first stripe light spot 210 and the second stripe light spot 220 on the mark surface. The plurality of stripe marks include a first stripe mark 101 and a second stripe mark 102. The first stripe mark 101 and the second stripe mark 102 have a first included angle between the extending directions of the stripes. The first included angle is an acute angle or a right angle. The first stripe light spot 210 and the second stripe light spot 220 have a second included angle between the extending directions of the stripes. The second included angle is an acute angle or a right angle. The first stripe light spot 210 is used to form a first Moiré stripe with the first stripe mark 101, and the second stripe light spot 220 is used to form a second Moiré stripe with the second stripe mark 102.

[0099] By obtaining the images of the Moiré stripes of the first stripe mark 101 and the second stripe mark 102, the position information of the pattern mark along the first detection direction and the second detection direction can be obtained. The first detection direction is perpendicular to or has an acute included angle with the extending direction of the first stripe mark 101. The second detection direction is perpendicular to or has an acute included angle with the extending direction of the second stripe mark 101.

[0100] The first stripe light spot 210 and the second stripe light spot 220 have a second included angle between the extending directions of the stripes. In the embodiment, the second acute included angle is the same as the first included angle. Specifically, in the embodiment, the first included angle is a right angle, and the second included angle is a right angle.

[0101] Specifically, in the embodiment, the number of the first fringe light spots 210 is two, and each first fringe light spot 210 forms a first Moiré fringe with the first fringe mark 101; the number of the second fringe light spots 220 is two, and each second fringe light spot 220 forms a second Moiré fringe with the two second fringe marks 102.

[0102] Reference Figure 4c In the third embodiment, the pattern light spot 200 includes the first fringe light spot 210 and the second fringe light spot 220, and the first fringe light spot 210 and the second fringe light spot 220 overlap. The third embodiment is different from the second embodiment in that:

[0103] The extension direction of the first fringe light spot 210 and the extension direction of the second fringe light spot 220 have a non-zero included angle. Specifically, the extension direction of the first fringe light spot 210 and the extension direction of the second fringe light spot 220 are perpendicular, or the extension direction of the first fringe light spot 210 and the extension direction of the second fringe light spot 220 have an acute included angle.

[0104] In the embodiment, the overlapping area of the first fringe light spot 210 and the second fringe light spot 220 completely covers the pattern mark; the overlapping area of the first fringe light spot 210 and the second fringe light spot 220 completely covering the pattern mark can obtain the detection image of the first fringe light spot 210 and the second fringe light spot 220 through one imaging process of the pattern mark. In other embodiments, the overlapping area of the first fringe light spot 210 and the second fringe light spot 220 partially covers the pattern mark.

[0105] In the embodiment, the detection device further includes a control device for controlling the light emitting device and the imaging device to obtain the first detection image of the pattern mark 200 and the second detection image of the second pattern mark 200.

[0106] The detection device further includes a processing module, and the processing module includes:

[0107] A Moiré shift acquisition unit is configured to acquire a Moiré shift between the Moiré fringe of the first pattern mark and the Moiré fringe of the second pattern mark according to the first detection image and the second detection image;

[0108] A detection magnification acquisition unit is configured to acquire a detection magnification of the detection image in the detection direction according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the Moiré fringe to a characteristic parameter of the fringe mark, and the characteristic parameter being a spatial frequency or a period;

[0109] The alignment error acquisition unit is configured to acquire the alignment error between the first pattern mark and the second pattern mark along the detection direction according to the Moiré offset and the detection magnification.

[0110] Specifically, the characteristic parameter is a period, and the alignment error acquisition unit is configured to acquire the alignment error between the first pattern mark and the second pattern mark according to a ratio of the Moiré offset and the detection magnification; or,

[0111] The characteristic parameter is a spatial frequency, and the alignment error acquisition unit is configured to acquire the alignment error between the first pattern mark and the second pattern mark according to a product of the Moiré offset and the detection magnification.

[0112] Figure 5 FIG. 5 is a structural schematic diagram of a second embodiment of the detection device provided by the present application.

[0113] Please refer to FIG. 5, the embodiment of the present application is the same as the embodiment shown in FIG. 1, and thus the same parts are not described herein again. The differences include: Figure 1

[0114] In the embodiment, the light emitting device includes a plurality of light emitting components, and the light emitting components are configured to form stripe light spots on the surface of the object 100. The stripe directions of the stripe light spots formed by the plurality of light emitting components are all different. The stripe light spots formed by the plurality of light emitting components are overlapped or separated.

[0115] The light emitting device includes a plurality of light emitting components, and the first stripe light spot 210 and the second stripe light spot 220 can be formed on the surface of the pattern mark by the different light emitting components respectively. Thus, the first Moiré stripe and the second Moiré stripe can be adjusted to reach the best state.

[0116] The light emitting device includes a plurality of light emitting components, and thus a plurality of stripe light spots can be formed on the surface of the pattern mark by the plurality of light emitting components simultaneously. The Moiré stripes formed by the different stripe marks and the stripe light spots can be imaged simultaneously, so that the detection speed can be improved. In addition, the plurality of stripe light spots can be formed on the surface of the pattern mark by the plurality of light emitting components simultaneously, so that each light emitting component can only generate one stripe light spot, and thus the design difficulty of the light emitting component can be reduced.

[0117] The azimuth angles of the incident light emitted by the plurality of light emitting components are different. In the embodiment, the angle values of the incident angles of the incident light emitted by the plurality of light emitting components are the same. In other embodiments, the angle values of the incident angles of the incident light emitted by the plurality of light emitting components can be different.

[0118] The pattern light spot 200 shown in FIG. 2 can be formed by the detection device of the embodiment. Figures 4a to 4c

[0119] Specifically, according to the Moiré offset and the detection magnification, the alignment error between the first pattern mark and the second pattern mark can be acquired.​​Figure 4a In the embodiment shown, the stripes of the stripe light spot formed by the plurality of light emitting components extend in different directions, and the light emitting components are switched to form stripe light spots on the marking surface in turn.

[0120] According to Figure 4b In the embodiment shown, the number of the plurality of light emitting components is two, and the two light emitting components form a first stripe light spot 210 and a second stripe light spot 220 on the marking surface, respectively, and the first stripe light spot 210 and the second stripe light spot 220 extend in different directions. Specifically, the first stripe light spot 210 and the second stripe light spot 220 extend in perpendicular directions.

[0121] According to Figure 4c In the embodiment shown, the plurality of light emitting components form a first stripe light spot 210 and a second stripe light spot 220 on the marking surface, respectively, and the first stripe light spot 210 and the second stripe light spot 220 at least partially overlap.

[0122] Figure 6 FIG. 3 is a structural schematic diagram of a third embodiment of the detection device of the present application.

[0123] Please refer to Figure 6 In the embodiment, the same as the embodiment shown is not repeated, and the differences include: Figure 1

[0124] In the embodiment, the central axis of the incident light and the central axis of the signal light are symmetric about the surface normal of the object 100, that is, the imaging device is used for bright field imaging in the embodiment, and the central axis of the incident light and the surface normal of the object have an acute angle.

[0125] Figure 7 FIG. 4 is a structural schematic diagram of a fourth embodiment of the detection device of the present application.

[0126] Please refer to Figure 7 In the embodiment, the same as the embodiment shown is not repeated, and the differences include: Figure 1

[0127] In the embodiment, the imaging device includes an objective lens 130 for collecting the signal light, and the incident light is incident on the surface of the object 100 from inside the objective lens 130; and a detection component 150 for forming the detection image according to the signal light collected by the objective lens 130.

[0128] In the embodiment, since the central axis of the incident light and the central axis of the signal light have a non-zero angle, the incident light and the signal light respectively pass through different regions of the objective lens 130, and the different regions of the objective lens 130 can be designed respectively, thereby reducing the design difficulty of the objective lens 130. ​​

[0129] In the embodiment, the light emitting device comprises one or more light emitting components, and the incident light of the one or more light emitting components is transmitted through the objective lens 130 to the surface of the object 100.

[0130] Figure 8 FIG. 4 is a structural schematic diagram of a fifth embodiment of the detection device according to the present application.

[0131] FIG. 5 is a structural schematic diagram of a sixth embodiment of the detection device according to the present application. Figure 8 FIG. 6 is a structural schematic diagram of a seventh embodiment of the detection device according to the present application. Figure 1 The same parts as those in the above embodiments are not described herein, and the differences include the following:

[0132] In the embodiment, the incident light is incident on the surface of the object through the objective lens 130. The central axis of the incident light is incident at a right angle. The detection device in the embodiment is a bright field imaging device.

[0133] In the embodiment, the detection device further comprises a beam splitter, which is configured to reflect the incident light into the objective lens 130 and transmit the signal light collected by the objective lens into the detection component 150. In another embodiment, the beam splitter is configured to transmit the incident light into the objective lens 130 and reflect the signal light collected by the objective lens into the detection component 150.

[0134] Figure 9 FIG. 7 is a flowchart of the steps of an embodiment of the detection method of the detection device according to the present application.

[0135] The present application further provides a detection method of a detection device, which comprises performing detection processing on the pattern light spot to obtain a detection image of the pattern light spot; the pattern light spot comprises a stripe light spot, and the stripe light spot comprises a plurality of stripes arranged repeatedly in the same direction; the pattern mark comprises a stripe mark, and the stripe mark comprises a plurality of stripes arranged repeatedly in the same direction; and the detection image comprises a sub-detection image of the stripe mark.

[0136] The detection processing comprises performing imaging processing on the stripe mark to obtain the sub-detection image of the stripe mark.

[0137] Figure 9 FIG. 8 is a flowchart of the steps of the imaging processing in an embodiment of the detection method of the detection device according to the present application.

[0138] FIG. 9 is a flowchart of the steps of the imaging processing in another embodiment of the detection method of the detection device according to the present application. Figure 9 The step of performing imaging processing on the stripe mark comprises the following steps:

[0139] Step S11, forming a fringe spot on the fringe mark surface by incident light of the light emitting device, the fringe spot and the fringe mark forming Moiré fringes, the incident light forming signal light after passing through the fringe mark, the signal light carrying information of the Moiré fringes, a fringe extension direction of the fringe spot and a fringe extension direction of the fringe mark having a preset included angle, the preset included angle being an acute angle;

[0140] Step S12, collecting the signal light by the imaging device, and forming a sub-detection image according to the collected signal light.

[0141] The object to be detected 100 includes a plurality of pattern marks respectively located in different film layers, the plurality of pattern marks including a first pattern mark and a second pattern mark.

[0142] The detection method includes: respectively performing detection processing on the plurality of pattern marks 200, the detection processing including one or more imaging processes. Respectively performing detection processing on the plurality of pattern marks 200 includes: performing first detection processing on the first pattern mark 200 to obtain a first detection image of the first pattern mark; and performing second detection processing on the second pattern mark 200 to obtain a second detection image of the second pattern mark.

[0143] Figure 10 A flowchart of each step of an embodiment of the detection method of the detection device according to the present application is shown.

[0144] Specifically, referring to Figure 10 , the plurality of pattern marks including a first pattern mark and a second pattern mark, the detection method including:

[0145] Step S21, performing first detection processing on the first pattern mark to obtain a first detection image of the first pattern mark;

[0146] Step S22, performing second detection processing on the second pattern mark to obtain a second detection image of the second pattern mark;

[0147] Step S23, obtaining a Moiré shift between Moiré fringes of the first pattern mark and Moiré fringes of the second pattern mark along the detection direction according to the first detection image and the second detection image;

[0148] Step S24, obtaining a detection magnification in the detection direction of the detection image according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the fringe mark to a characteristic parameter of the fringe mark, the characteristic parameters including spatial frequency or period;

[0149] Step S25, according to the Moire shift and the detection magnification, obtaining the alignment error between the first pattern mark and the second pattern mark.

[0150] Specifically, in combination with reference to Figure 1 To Fig. 4, step S21 is performed, the first detection processing is performed on the first pattern mark 200, and the first detection image of the first pattern mark is obtained; step S22 is performed, the second detection processing is performed on the second pattern mark 200, and the second detection image of the second pattern mark is obtained.

[0151] The first detection processing includes: performing the imaging processing on the first pattern mark 200 one or more times, obtaining a first detection image group of the first pattern mark 200, and the detection image group includes one or more detection images.

[0152] The second detection processing includes: performing the imaging processing on the second pattern mark 200 one or more times, obtaining a second detection image group of the second pattern mark 200, and the second detection image group includes one or more detection images.

[0153] In the embodiment, the pattern mark 200 includes a plurality of stripe marks, the plurality of stripe marks include a first stripe mark 101 and a second stripe mark 102, the first stripe mark 101 and the second stripe mark 102 have a first included angle between the extension directions of the stripes, and the first included angle is a right angle or an acute angle.

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

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

[0156] Specifically, the first imaging processing includes: forming a first stripe light spot 210 on the surface of the first stripe mark 101 by an incident light of a light emitting device, the first stripe light spot 210 and the first stripe mark 101 form a first Moire stripe, and the incident light forms a first signal light after passing through the first stripe mark 101; collecting the first signal light by the imaging device, and obtaining a first sub-detection image of the first stripe mark 101 according to the collected first signal light.

[0157] The second imaging process includes: forming a second fringe light spot 220 on the surface of the second fringe mark 102 by the incident light of the light emitting device, the second fringe light spot 220 is used to form a second Moiré fringe with the second fringe mark 102, and the incident light forms a second signal light after passing through the second fringe mark 102, and the second signal light carries information of the second Moiré fringe; collecting the second signal light by the imaging device, and obtaining a second sub-detection image of the second fringe mark 102 according to the collected second signal light.

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

[0159] Specifically, in the embodiment shown in the figure, after the first sub-detection image is obtained, the light emitting device forms a second fringe light spot 220 on the surface of the second fringe mark 102. Figure 4a

[0160] Specifically, after the first sub-detection image is obtained, the second pattern light spot is formed on the surface of the second fringe mark 101 by adjusting the shaping element.

[0161] In the embodiment shown in the figure, the first detection image and the second detection image are obtained by the imaging device. Figure 4b And 4c In the embodiment shown in the figure, the pattern mark includes a first pattern mark and a second pattern mark; the first pattern mark and the second pattern mark both include a first fringe mark 101 and a second fringe mark 102.

[0162] The pattern light spot includes a first fringe light spot and a second fringe light spot, the pattern mark includes a first fringe mark and a second fringe mark, the first fringe light spot can form a first Moiré fringe with the first fringe mark, and the first included angle is an acute angle or a right angle; the second fringe mark forms a second Moiré fringe with the second fringe light spot, and the second included angle is an acute angle or a right angle, so that the offset of the pattern 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] In the embodiment shown in the figure, the first detection image and the second detection image are obtained by the imaging device. Figure 4b And 4c In the embodiment shown in the figure, after the first fringe light spot 210 is formed on the surface of the first fringe mark 101 and the second fringe light spot 220 is formed on the surface of the second fringe mark 102 by the light emitting device, the first sub-detection image and the second sub-detection image are obtained by the imaging device.

[0164] Step S23 is performed to obtain the Moiré offset between the Moiré fringe of the first pattern mark and the Moiré fringe of the second pattern mark along the detection direction according to the first detection image and the second detection image.

[0165] ​The detection direction is perpendicular to or has an acute included angle with the extension direction of the stripe mark in the stripe mark of the pattern mark.

[0166] The step of acquiring the Moiré shift between the Moiré fringes of the first pattern mark and the Moiré fringes of the second pattern mark in the detection direction according to the first detection image and the second detection image comprises: acquiring a first center position of the Moiré fringes of the first pattern mark according to the first detection image; acquiring a second center position of the Moiré fringes of the second pattern mark according to the second detection image; and acquiring the Moiré shift according to the first center position and the second center position.

[0167] Specifically, the step of acquiring the first center position of the Moiré fringes of the first pattern mark according to the first detection image comprises: acquiring a gray scale curve of the Moiré fringe image in the first detection image in the detection direction; and fitting the gray scale curve to acquire the first center position.

[0168] The step of acquiring the second center position of the Moiré fringes of the second pattern mark according to the second detection image comprises: acquiring a gray scale curve of the Moiré fringe image in the second detection image in the detection direction; and fitting the gray scale curve to acquire the second center position.

[0169] In the embodiment, the first detection image and the second detection image each comprise a first sub-detection image and a second sub-detection image.

[0170] The step of acquiring the Moiré shift between the Moiré fringes of the first pattern mark and the Moiré fringes of the second pattern mark according to the first detection image and the second detection image comprises: acquiring a first shift between a first Moiré fringe of the first pattern mark and a first Moiré fringe of the second pattern mark in a first detection direction according to a first sub-detection image of the first detection image and a first sub-detection image of the second detection image; and acquiring a second shift between a second Moiré fringe of the first pattern mark and a second Moiré fringe of the second pattern mark in a second detection direction according to a second sub-detection image of the first detection image and a second sub-detection image of the second detection image; the first detection direction and the second detection direction are perpendicular to or have an acute included angle.

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

[0172] The step S24 is performed to acquire a detection magnification of the detection image in the detection direction according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the Moiré fringe to a characteristic parameter of the stripe mark, the characteristic parameter being a spatial frequency or a period.

[0173] Since the spatial frequency of the moire fringes is low, the imaging device can image the moire fringes, but it is difficult to image the high-frequency signals of the fringe marks. Therefore, the first detection image includes an image of the moire fringes of the first pattern marks; and the first detection image includes an image of the moire fringes of the second pattern marks.

[0174] According to the detection magnification in the detection direction obtained from 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 moire fringes to the spatial frequency of the fringe marks, including: obtaining a first characteristic parameter of the moire fringes of the first pattern marks in the detection direction according to the first detection image, the first characteristic parameter being a spatial frequency or a period; and obtaining the detection magnification according to the ratio of the first characteristic parameter to a first characteristic parameter of the fringe marks in the first pattern marks.

[0175] Specifically, obtaining the detection magnification according to the ratio of the first characteristic parameter of the first pattern marks to the first characteristic parameter of the fringe marks in the first pattern marks includes:

[0176] When the first characteristic parameter is a spatial frequency, the detection magnification is: n=v2 / v1, where n is the detection magnification, v2 is the spatial frequency of the fringe marks in the first pattern marks, and v1 is the spatial frequency of the moire fringes of the first pattern marks. When the first characteristic parameter is a period, the detection magnification is: n=d1 / d2, where n is the detection magnification, d2 is the period of the fringe marks in the first pattern marks, and d1 is the period of the moire fringes of the first pattern marks.

[0177] Alternatively, the detection magnification is: n=v1 / v2, where n is the detection magnification, v2 is the spatial frequency of the fringe marks in the first pattern marks, and v1 is the spatial frequency of the moire fringes of the first pattern marks; or, the detection magnification is: n=d2 / d1, where n is the detection magnification, d2 is the period of the fringe marks in the first pattern marks, and d1 is the period of the moire fringes of the first pattern marks.

[0178] In other embodiments, the step of obtaining the magnification of the detection image in the detection direction according to one or both of the first detection image and the second detection image comprises: obtaining a second characteristic parameter of the moire fringe image of the second pattern mark in the detection direction according to the second detection image, the second characteristic parameter being a spatial frequency or a period; and obtaining the magnification according to a ratio of the second characteristic parameter and a second characteristic parameter of the fringe mark in the second pattern mark. Since the extension direction and the period of the corresponding fringe marks in the first pattern mark and the second pattern mark are the same, the magnification of the moire fringe of the first detection image relative to the fringe mark of the first pattern mark is equal to the magnification of the moire fringe of the second detection image relative to the fringe mark of the second pattern mark.

[0179] However, due to detection errors or process errors, the magnification obtained from the first detection image can be different from the magnification obtained from the second detection image. In another embodiment, the step of obtaining the magnification of the detection image in the detection direction according to one or both of the first detection image and the second detection image comprises: obtaining a first detection magnification of the first detection image in the detection direction according to the first detection image; obtaining a second detection magnification of the second detection image in the detection direction according to the second detection image; and obtaining the detection magnification by averaging the first detection magnification and the second detection magnification.

[0180] The pattern mark comprises: a first fringe mark and a second fringe mark. The first detection image and the second detection image each comprise a first sub-detection image and a second sub-detection image.

[0181] The detection method comprises repeating the step of obtaining the magnification of the detection image in the detection direction according to one or both of the first detection image and the second detection image, until a first detection magnification in a first detection direction and a second detection magnification in a second detection direction are obtained.

[0182] The step of repeating the step of obtaining the magnification of the detection image in the detection direction according to one or both of the first detection image and the second detection image comprises: obtaining a first detection magnification of the detection image in a first detection direction according to one or both of the first sub-detection image and the second sub-detection image of the first detection image and the second detection image; and obtaining a second detection magnification of the detection image in a second detection direction according to one or both of the first sub-detection image and the second sub-detection image of the first detection image and the second detection image.

[0183] In the embodiments provided by the present application, the first detection image and the second detection image are the same image, and the first detection process and the second detection process are the same detection process, that is, the image of the object to be detected can be obtained by performing one imaging process on the object to be detected, and the image of the object to be detected 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 processes and second detection processes, respectively.

[0184] In step S25, the alignment error between the first pattern mark and the second pattern mark along the detection direction is obtained according to the Moiré offset and the detection magnification.

[0185] Specifically, when the detection magnification is n=v2 / v1, where n is the detection magnification, v2 is the spatial frequency of the stripe mark in the first pattern mark, and v1 is the spatial frequency of the Moiré stripe of the first pattern mark; or 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 stripe 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 according to the Moiré offset and the detection magnification includes: obtaining the ratio of the Moiré offset to the detection magnification to obtain the alignment error.

[0186] When the detection magnification is n=v1 / v2, where n is the detection magnification, v2 is the spatial frequency of the stripe mark in the first pattern mark, and v1 is the spatial frequency of the Moiré stripe 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 stripe 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 according to the Moiré offset and the detection magnification includes: obtaining the product of the Moiré offset and the detection magnification to obtain the alignment error.

[0187] Specifically, the characteristic parameter is the period, and the alignment error between the first pattern mark and the second pattern mark is obtained according to the ratio of the Moiré offset to the detection magnification; or the characteristic parameter is the spatial frequency, and the alignment error between the first pattern mark and the second pattern mark is obtained according to the product of the Moiré offset and the detection magnification.

[0188] Specifically, in the embodiment, the first pattern mark includes a first fringe mark 101 and a second fringe mark 102. The imaging device is configured to form a first fringe spot 210 and a second fringe spot 220, the first fringe mark 101 and the first fringe spot 210 form a first Moiré fringe, and the second fringe mark 101 and the second fringe spot 220 form a second Moiré fringe. The first detection image and the second detection image both include images of the first Moiré fringe and the second Moiré fringe.

[0189] The detection method includes: performing, on the first Moiré fringe, a step of obtaining a Moiré shift between the Moiré fringe of the first pattern mark and the Moiré fringe of the second pattern mark according to the first detection image and the second detection image, and obtaining an alignment error between the first pattern mark and the second pattern mark along a first detection direction according to the Moiré shift and the detection magnification; and performing, on the second Moiré fringe, a step of obtaining a Moiré shift between the Moiré fringe of the first pattern mark and the Moiré fringe of the second pattern mark according to the first detection image and the second detection image, and obtaining an alignment error between the first pattern mark and the second pattern mark along a second detection direction according to the Moiré shift and the detection magnification.

[0190] Specifically, the step of repeatedly obtaining an alignment error between the first pattern mark and the second pattern mark along the detection direction according to the Moiré shift and the detection magnification includes: obtaining an alignment error between the first pattern mark and the second pattern mark along the first detection direction according to the first Moiré shift and the first detection magnification; and obtaining an alignment error between the first pattern mark and the second pattern mark along the second detection direction according to the second Moiré shift and the second detection magnification. Although the present application is disclosed as above, the present application is not limited thereto.

[0191] Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A detection device, characterized by A detection device for overlay measurement of a semiconductor device, the detection device comprising: An illumination device for generating an incident light to illuminate a test object, the test object being a semiconductor device, the test object having a surface with pattern marks, the test object comprising a plurality of pattern marks respectively located in different film layers, the plurality of pattern marks having a first pattern mark and a second pattern mark, the pattern mark comprising a stripe mark, the stripe mark comprising a plurality of stripes arranged repeatedly in a same direction, the incident light being configured to form a pattern spot on the surface of the pattern mark, the pattern spot comprising a stripe spot, the stripe spot comprising a plurality of stripes arranged repeatedly in the same direction, the stripe spot being configured to form a Moire fringe with the stripe mark, the incident light being configured to form a signal light after passing through the pattern mark, the signal light carrying information of the Moire fringe, the stripe spot having a preset angle with the stripe mark, the preset angle being an acute angle; An imaging device configured to collect the signal light and form a detection image according to the collected signal light; A control device configured to control the illumination device and the imaging device to acquire a first detection image of the first pattern mark and a second detection image of the second pattern mark; A processing module comprising: a Moire shift acquisition unit configured to acquire a Moire shift between the Moire fringe of the first pattern mark and the Moire fringe of the second pattern mark in a detection direction according to the first detection image and the second detection image; a detection magnification acquisition unit configured to acquire a detection magnification of the detection image in the detection direction according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the Moire fringe to a characteristic parameter of the stripe mark, the characteristic parameter being a spatial frequency or a period; and an alignment error acquisition unit configured to acquire an alignment error between the first pattern mark and the second pattern mark in the detection direction according to the Moire shift and the detection magnification.

2. The detection device of claim 1, wherein, The imaging device comprises: An objective lens configured to collect the signal light; and a detection assembly configured to form the detection image according to the signal light collected by the objective lens; The incident light is incident on the surface of the test object from outside the objective lens; or the detection device further comprises a beam splitter configured to propagate the incident light towards the objective lens, the objective lens being further configured to collect the incident light and make the incident light reach the surface of the test object; and the beam splitter is further configured to split the signal light collected by the objective lens from the incident light and propagate the signal light towards the detector.

3. The detection device of claim 1, wherein, The illumination device comprises one or more illumination assemblies, each of the illumination assemblies comprising: a light source configured to emit an initial light beam; and a shaping assembly configured to shape the initial light beam to form the incident light, the incident light being configured to form the pattern spot on the surface of the test object; Or, the illumination assembly comprises a display screen having a display pattern, and the display screen is configured to project the display pattern to the surface of the test object to form the pattern spot; One or both of the extension direction of the stripe in the stripe spot and the period of the stripe spot are adjustable.

4. The detection device of claim 3, wherein, The shaping assembly is configured to rotate around an optical axis of the shaping assembly; or the light emitting device is configured to rotate around an optical axis of the light emitting device.

5. The detection device according to claim 1 or 3, characterized in that The pattern mark includes a plurality of stripe marks, the plurality of stripe marks include a first stripe mark and a second stripe mark, the first stripe mark and the second stripe mark have a first included angle between the extension directions of the stripes, and the first included angle is a right angle or an acute angle; The pattern spot includes a plurality of stripe spots, the plurality of stripe spots include a first stripe spot and a second stripe spot, the first stripe spot and the second stripe spot have a second included angle between the extension directions of the stripes, and the second included angle 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; and the second included angle is the same as the first included angle.

6. The detection device of claim 1, wherein, The period of the stripe spot is the same as or different from that of the stripe mark; and the included angle between the extension directions of the stripes in the stripe spot and the stripes in the stripe mark is 1°-30°.

7. The detection device of claim 1, wherein, The feature parameter is a period, and the alignment error acquisition unit is configured to acquire an alignment error between the first pattern mark and the second pattern mark according to a ratio of the Moiré offset to the detection magnification; or The feature parameter is a spatial frequency, and the alignment error acquisition unit is configured to acquire an alignment error between the first pattern mark and the second pattern mark according to a product of the Moiré offset and the detection magnification.

8. A detection method based on the detection apparatus according to any one of claims 1 to 7, characterized by, For overlay measurement of a semiconductor device as a test object, the detection method includes performing a detection process on a pattern spot to obtain a detection image of the pattern spot; the pattern spot includes a stripe spot, and the stripe spot includes a plurality of stripes arranged repeatedly in the same direction; and the pattern mark includes a stripe mark, and the stripe mark includes a plurality of stripes arranged repeatedly in the same direction. The detection image includes a sub-detection image of the stripe mark. The detection process includes performing an imaging process on the stripe mark to obtain a sub-detection image of the stripe mark. The imaging process on the stripe mark includes forming a stripe spot on the surface of the stripe mark by incident light of the light emitting device, forming a Moiré fringe between the stripe spot and the stripe mark, forming signal light after the incident light passes through the stripe mark, the signal light carrying information of the Moiré fringe, and the extension direction of the stripe in the stripe spot having a preset included angle with the extension direction of the stripe in the stripe mark, and the preset included angle being an acute angle. The signal light is collected by an imaging device, and a sub-detection image is formed according to the collected signal light.

9. The detection method according to claim 8, characterized in that, The test object includes a plurality of pattern marks respectively located in different film layers, and the plurality of pattern marks include a first pattern mark and a second pattern mark. The detection method further comprises: 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 shift between the Moiré fringes of the first pattern mark and the Moiré fringes of the second pattern mark along a detection direction according to the first detection image and the second detection image; obtaining a detection magnification of the detection image in the detection direction according to one or a combination of the first detection image and the second detection image, the detection magnification being a ratio of a characteristic parameter of the Moiré fringes to a characteristic parameter of the fringe mark, the characteristic parameters including spatial frequency or period; and obtaining an alignment error between the first pattern mark and the second pattern mark along the detection direction according to the Moiré shift and the detection magnification.

10. The detection method of claim 8, wherein, The pattern mark comprises a plurality of fringe marks, the plurality of fringe marks comprising a first fringe mark and a second fringe mark, the first fringe mark and the second fringe mark having a first included angle between the extension directions of the fringes, the first included angle being a right angle or an acute angle; and the pattern spot comprises a first fringe spot and a second fringe spot, the first fringe spot and the second fringe spot having a second included angle between the extension directions of the fringes, the second included angle being a right angle or an acute angle. The step of performing the detection process on the pattern mark comprises: performing a first imaging process on the first fringe mark; and performing a second imaging process on the second fringe mark. The first imaging process comprises: forming a first fringe spot on a surface of the first fringe mark by an incident light of a light emitting device, the first fringe spot and the first fringe mark forming a first Moiré fringe, the incident light forming a first signal light after passing through the first fringe mark, the first signal light carrying information of the first Moiré fringe; and collecting the first signal light by an imaging device, and obtaining a first sub-detection image of the first fringe mark according to the collected first signal light. The second imaging process comprises: forming a second fringe spot on a surface of the second fringe mark by an incident light of a light emitting device, the second fringe spot and the second fringe mark forming a second Moiré fringe, the incident light forming a second signal light after passing through the second fringe mark, the second signal light carrying information of the second Moiré fringe; and collecting the second signal light by the imaging device, and obtaining a second sub-detection image of the second fringe mark according to the collected second signal light.

11. The detection method according to claim 10, characterized in that, The first included angle is the same as the second included angle.

12. The detection method of claim 10, wherein, The first detection image and the second detection image each comprise the first sub-detection image and the second sub-detection image. The step of acquiring the Moiré shift between the Moiré fringes of the first pattern mark and the Moiré fringes of the second pattern mark according to the first detection image and the second detection image comprises: acquiring a first shift 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 according to a first sub-detection image of the first detection image and a first sub-detection image of the second detection image; acquiring a second shift 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 according to a second sub-detection image of the first detection image and a second sub-detection image of the second detection image; the first detection direction and the second detection direction are perpendicular or have an acute included angle.

13. The method of claim 9, wherein, After the first detection image is acquired, a second fringe light spot is formed on the second fringe mark surface by the light emitting device; or, a first fringe light spot is formed on the first fringe mark surface by the light emitting device, and after the second fringe light spot is formed on the second fringe mark surface, the first sub-detection image and the second sub-detection image are acquired by the imaging device.

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