Wafer alignment measurement device and measurement method, bonding device and semiconductor structure

Abstract

Embodiments of the present application provide a wafer alignment measurement device and measurement method, a bonding device, and a semiconductor structure. The alignment measurement device includes: a light source assembly, a spectrometer, a polarizer, and an imaging assembly; the light source assembly is used to provide original light propagating along a second direction; the spectrometer is used to reflect the original light based on the polarization direction; wherein the reflected light is a first light with a first polarization direction; the first light propagates along the first direction through the polarizer to a first alignment mark located on the first wafer, and propagates through the first wafer to a second alignment mark located on the second wafer; the second light reflected by the first alignment mark and the second alignment mark has a second polarization direction after passing through the polarizer; the second light with the second polarization direction propagates along a third direction through the spectrometer to the imaging assembly; the imaging assembly is used to collect first moiré fringes formed by the second light; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of integrated circuit technology, and more particularly to a wafer alignment measurement device and measurement method, a bonding device, and a semiconductor structure. Background Art

[0002] In the chip packaging industry, bonding technology is often used during the manufacturing process to further reduce chip area and increase integration. To ensure bonding quality, minimize the impact of the bonding process on inter-chip electrical signal transmission, and ensure reliable signal transmission, bond alignment deviation must be strictly controlled within a small range.

[0003] Accurately measuring the positional deviation between wafers improves bonding accuracy, which is conducive to further realizing high-density, high-performance chip stacking. Summary of the Invention

[0004] In view of this, embodiments of the present application provide a wafer alignment measurement device and measurement method, a bonding device, and a semiconductor structure.

[0005] To achieve the above objectives, the technical solution of the embodiment of the present application is implemented as follows:

[0006] An embodiment of the present application provides a wafer alignment measurement device, comprising: a light source assembly, a beam splitter, a polarizer, and an imaging assembly; wherein the imaging assembly, the beam splitter, and the polarizer are sequentially arranged along a first direction; the light source assembly and the beam splitter are arranged along a second direction; wherein the first direction and the second direction have a first angle;

[0007] The light source assembly is used to provide original light propagating along the second direction;

[0008] The beam splitter is used to reflect the original light based on the polarization direction; wherein the reflected light is a first light with a first polarization direction;

[0009] The first light propagates along the first direction through the polarizer to a first alignment mark on the first wafer, and then propagates through the first wafer to a second alignment mark on the second wafer;

[0010] The second light reflected by the first alignment mark and the second alignment mark has a second polarization direction after passing through the polarizer; the second polarization direction is different from the first polarization direction;

[0011] The second light with a second polarization direction transmits the beam splitter along a third direction and propagates to the imaging component; wherein, the third direction is opposite to the first direction; the imaging component is used to collect the first moiré fringes formed by the second light; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned.

[0012] In some embodiments, the alignment measurement device further comprises:

[0013] A data processing device is connected to the imaging component, and is used to determine whether the first alignment mark and the second alignment mark are aligned based on the first moiré fringes and preset second moiré fringes.

[0014] In some embodiments, the imaging assembly includes a tube lens and an image sensor;

[0015] The cylindrical lens is located between the beam splitter and the image sensor, and is used to converge the second light passing through the beam splitter;

[0016] The image sensor is used to collect the first moiré fringes formed by the second light.

[0017] In some embodiments, the alignment measurement device further comprises:

[0018] An objective lens assembly is located between the polarizer and the first wafer, and is used to focus light to a preset position between the first alignment mark and the second alignment mark.

[0019] In some embodiments, the light source assembly includes a laser emitter;

[0020] The laser emitter is used to emit the original light with a wavelength greater than that of visible light.

[0021] In some embodiments, the first alignment mark includes a plurality of first grating stripes arranged along a fourth direction, or the first alignment mark includes a plurality of first grating rings arranged in concentric circles; the fourth direction is parallel to the surface of the first wafer;

[0022] And / or, the second alignment mark includes a plurality of second grating stripes arranged along a fifth direction, or the second alignment mark includes a plurality of second grating rings in the form of concentric circles; the fifth direction is parallel to the surface of the second wafer.

[0023] In some embodiments, along the fourth direction, the first grating stripes are arranged according to a first period;

[0024] Along the fifth direction, the second grating stripes are arranged according to a second period;

[0025] An absolute value of a difference between the first period and the second period is greater than 0 and less than or equal to a preset first threshold.

[0026] In some embodiments, along the first direction, there is a first distance between the first alignment mark and the second alignment mark;

[0027] The difference between the width of the first grating stripes and the first distance is smaller than a preset second threshold; the difference between the width of the first grating rings and the first distance is smaller than a preset third threshold;

[0028] and / or

[0029] The difference between the width of the second grating stripes and the first distance is smaller than the second threshold; the difference between the width of the first grating rings and the first distance is smaller than the third threshold.

[0030] In some embodiments, the material of the first grating stripes and / or the material of the second grating stripes include a metal material.

[0031] The embodiment of the present application provides a bonding device, comprising any one of the alignment measurement devices and a control component described above,

[0032] The control component is used to move the first wafer and / or the second wafer to be bonded according to measurement information of the alignment measurement device, so that the first alignment mark and the second alignment mark are aligned.

[0033] An embodiment of the present application provides a semiconductor structure, including a first wafer;

[0034] The first wafer includes a first alignment mark; the first alignment mark includes a plurality of first grating stripes arranged along a fourth direction, or the first alignment mark includes a plurality of first grating rings in the form of concentric circles;

[0035] The first alignment mark is used to reflect light together with the second alignment mark located on the second wafer to form first moiré fringes; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned.

[0036] In some embodiments, the first wafer further includes a first silicon substrate and at least one first transmission layer;

[0037] The first alignment mark is located on a side of the first transmission layer close to the first silicon substrate; or the first alignment mark is located on a side of the first transmission layer away from the first silicon substrate;

[0038] The transmittance of the first transmission layer to light is greater than or equal to a preset first transmittance;

[0039] The transmittance of the first silicon substrate to light is greater than or equal to a preset second transmittance.

[0040] In some embodiments, the first transmittance is greater than or equal to 85%; and / or the second transmittance is greater than or equal to 50%.

[0041] In some embodiments, the semiconductor structure further includes the second wafer;

[0042] The first wafer is bonded to the second wafer;

[0043] The second alignment mark includes a plurality of second grating stripes arranged along a fifth direction, or the second alignment mark includes a plurality of second grating rings in the form of concentric circles.

[0044] In some embodiments, the second wafer further includes a second silicon substrate and at least one second transmissive layer; the second alignment mark is located on a side of the second transmissive layer close to the second silicon substrate, or the second alignment mark is located on a side of the second transmissive layer away from the second silicon substrate;

[0045] The transmittance of the second transmission layer to light is greater than or equal to the first transmittance;

[0046] The transmittance of the second silicon substrate to light is greater than or equal to the second transmittance.

[0047] In some embodiments, the first transmission layer includes silicon dioxide material and / or silicon nitride material.

[0048] In some embodiments, the first wafer includes a plurality of first chip regions and scribe line regions located between the first chip regions; and the first alignment mark is located within the scribe line regions.

[0049] The present invention provides a wafer alignment measurement method, comprising:

[0050] Using the light source assembly to provide original light propagating along a second direction;

[0051] After being reflected by the beam splitter, the original light propagates along a first direction through the polarizer to a first alignment mark on the first wafer, and then propagates through the first wafer to a second alignment mark on the second wafer;

[0052] The light reflected by the beam splitter is a first light having a first polarization direction; the light reflected by the first alignment mark and the second alignment mark is a second light, and the second light has a second polarization direction after passing through the polarizer; the second polarization direction is different from the first polarization direction;

[0053] collecting, using an imaging component, first moiré fringes formed by the second light having a second polarization direction after passing through the beam splitter; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned;

[0054] The imaging component, the beam splitter and the polarizer are sequentially arranged along a first direction, and the light source component and the beam splitter are arranged along a second direction; the first direction and the second direction have a first angle.

[0055] In some embodiments, the alignment measurement method further comprises:

[0056] determining a translation offset between the first alignment mark and the second alignment mark according to the first moiré fringe and a preset second moiré fringe;

[0057] The first wafer and / or the second wafer are horizontally moved according to the translation offset so that the first alignment mark is aligned with the second alignment mark.

[0058] In some embodiments, the alignment measurement method further comprises:

[0059] determining an offset angle between the first alignment mark and the second alignment mark according to a normal vector of the first alignment mark and a normal vector of the second alignment mark;

[0060] The horizontal rotation angle of the first wafer and / or the second wafer is adjusted according to the offset angle, so that the first alignment mark and the second alignment mark are parallel to the same plane.

[0061] The wafer alignment measurement device provided in the embodiment of the present application, on the one hand, utilizes light with good penetrability relative to the first wafer or the second wafer, so that it can pass through the first wafer to the second alignment mark of the second wafer, and can directly observe or measure whether the first alignment mark and the second alignment mark are aligned, which simplifies the alignment identification steps and reduces the measurement error caused by separate observation. On the other hand, by utilizing the first light and the second light with different polarization directions, the transmission and reflection selection of the incident light and the reflected light of the alignment mark (the first alignment mark or the second alignment mark) can be achieved. The imaging component collects the reflected second light, which can increase the imaging quality of the first moiré fringes and is conducive to improving the extraction of alignment information. On the third hand, the use of the first moiré fringes can amplify the deviation between the alignment marks, which is conducive to improving the accuracy of alignment measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 Wafer alignment measurement device provided in the embodiment of the present application Figure 1 ;

[0063] Figure 2 Wafer alignment measurement device provided in the embodiment of the present application Figure 2 ;

[0064] Figure 3 Wafer alignment measurement device provided in the embodiment of the present application Figure 3 ;

[0065] Figure 4 Wafer alignment measurement device provided in the embodiment of the present application Figure 4 ;

[0066] Figure 5A The first alignment mark provided in the embodiment of the present application is shown as follows: Figure 1 ;

[0067] Figure 5B The first alignment mark provided in the embodiment of the present application is shown as follows: Figure 2 ;

[0068] Figure 6 The first alignment mark provided in the embodiment of the present application is shown as follows: Figure 3 ;

[0069] Figure 7 A comparison diagram of the first alignment mark and the second alignment mark in an embodiment of the present application;

[0070] Figure 8 A schematic diagram of the first moiré fringe provided in an embodiment of the present application;

[0071] Figure 9 A schematic diagram of wafer positions provided in an embodiment of the present application;

[0072] Figure 10 FIG5 is a wafer alignment measurement device according to an embodiment of the present application;

[0073] Figure 11 A schematic diagram of a signal curve provided in an embodiment of the present application;

[0074] Figure 12 A schematic diagram of the steps of the wafer alignment measurement method provided in an embodiment of the present application;

[0075] Figure 13 A schematic structural diagram of a bonding device provided in an embodiment of the present application;

[0076] Figure 14 Schematic diagram of the semiconductor structure provided in the embodiment of the present application Figure 1 ;

[0077] Figure 15A Schematic diagram of the semiconductor structure provided in the embodiment of the present application Figure 2 ;

[0078] Figure 15BSchematic diagram of the semiconductor structure provided in the embodiment of the present application Figure 3 ;

[0079] Figure 16A Schematic diagram of the semiconductor structure provided in the embodiment of the present application Figure 4 ;

[0080] Figure 16B Structural schematic diagram 5 of the semiconductor structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0081] The following will be combined with the embodiments of this application and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0082] In the following description, numerous specific details are provided to provide a more thorough understanding of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced without one or more of these details. In other instances, certain technical features known in the art are not described to avoid confusion with the present application; that is, all features of actual embodiments are not described herein, nor are well-known functions and structures described in detail.

[0083] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0084] In order to fully understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below. However, in addition to these detailed descriptions, the present application may also have other implementation methods.

[0085] In bonding alignment technology, a high-precision optical microscope or imaging device is generally used to take pictures of specific alignment mark patterns pre-designed on the wafer surface, and then the alignment deviation is calculated based on the center positions of the two alignment mark patterns.

[0086] However, this alignment method is limited by the optical system's resolution and the image processing algorithm's accuracy. To further improve the optical system's diffraction resolution limit, the light source wavelength needs to be further reduced to lower the diffraction limit and improve the optical system's resolution. However, the shorter the light source wavelength, the higher its energy, which is more easily absorbed or scattered by matter, making it difficult to obtain sufficient effective light signals and, consequently, difficult to obtain high-quality images.

[0087] In view of this, an embodiment of the present application provides a wafer alignment measurement device, such as Figure 1 As shown, the wafer alignment measurement device 100 includes: a light source assembly 101, a beam splitter 102, a polarizer 103, and an imaging assembly 104; wherein the imaging assembly 104, the beam splitter 102, and the polarizer 103 are arranged in sequence along a first direction (negative direction of the Z axis); the light source assembly 101 and the beam splitter 102 are arranged along a second direction; wherein the first direction and the second direction have a first angle;

[0088] The light source assembly 101 is used to provide an original light L0 propagating along a second direction;

[0089] The beam splitter 102 is configured to reflect the original light L0 based on the polarization direction; wherein the reflected light is a first light L1 having a first polarization direction;

[0090] The first light L1 propagates along the first direction through the polarizer 103 to the first alignment mark 106 located on the first wafer 105 , and then propagates through the first wafer 105 to the second alignment mark 108 located on the second wafer 107 .

[0091] The second light reflected by the first alignment mark 106 and the second alignment mark 108 has a second polarization direction after passing through the polarizer 103; the second polarization direction is different from the first polarization direction;

[0092] The second light L2 having a second polarization direction transmits the beam splitter 102 along a third direction (positive direction of the Z axis) and propagates to the imaging component 104; wherein the third direction is opposite to the first direction; the imaging component 104 is used to collect the first moiré fringes formed by the second light L2; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned.

[0093] That is, the propagation path of the light is light source assembly 101 - beam splitter 102 - polarizer 103 - first alignment mark 106 / second alignment mark 108 - polarizer 103 - beam splitter 102 - imaging assembly 104 in sequence.

[0094] The beam splitter 102 can separate light into polarized light with different polarization directions, reflecting light with certain polarization directions and transmitting light with other polarization directions, thereby achieving light separation. The original light L0 can be natural light (or other light without a specific polarization direction) or light with one or more polarization directions. For example, the original light L0 is natural light, which can be separated into two beams of light: transmitted light and reflected light after passing through the beam splitter 102, where the reflected light is the first light L1 with a first polarization direction. The original light L0 can also be light that includes the first polarization direction, for example, only light with the first polarization direction or light with one or more polarization directions. If the original light L0 does not include polarized light that can transmit the beam splitter 102, then after passing through the beam splitter 102, there is no transmitted light and only the reflected first light L1.

[0095] The polarizer 103 can change the polarization direction or polarization state of light, that is, the polarization direction or polarization state of the light passing through the polarizer 103 is different from the polarization direction or polarization state of the light before passing through the polarizer 103. In this way, the reflected second light can have a second polarization direction after passing through the polarizer 103, and the second polarization direction is different from the first polarization direction, can pass through the spectrometer 102, and propagate along the third direction to the imaging component 104. It can be understood that the first light L1 changes its polarization direction or polarization state once after passing through the polarizer 103, and the reflected second light changes its polarization direction or polarization state again after passing through the polarizer 103. The specific changes of the polarizer 103 during these two light transmissions are not limited here, only that the second light has a second polarization direction that can pass through the spectrometer 102 after passing through the polarizer 103. In this way, the first light L1 can be reflected by the spectrometer 102, while the second light L2 passes through the spectrometer 102 and is collected by the imaging component 104 without being interfered with by the original light L0 or the first light L1.

[0096] The imaging component 104 collects the reflected second light L2 to form a first moiré fringe. Moiré fringe is an interference phenomenon observed in optical experiments, and its optical principle is related to the wave nature of light and the interference of light. When two sets of parallel periodic fringes are superimposed, a new light and dark alternating stripe pattern is generated, which is called moiré fringe. Moiré fringe can amplify tiny relative displacements, and its high sensitivity is conducive to improving the accuracy of alignment measurement. In the embodiment of the present application, the first moiré fringe formed by the second light reflected by the first alignment mark and the second alignment mark can be used to directly determine whether the first alignment mark 106 and the second alignment mark 108 are aligned, and to calculate the alignment deviation between the first alignment mark 106 and the second alignment mark 108.

[0097] It can be understood that the first alignment mark and the second alignment mark may be in any shape that can reflect light to form moiré fringes, such as a stripe or circular grating shape.

[0098] In addition, the above-mentioned first light L1 needs to pass through the first wafer 105 to irradiate the second wafer 107 and be reflected by the second alignment mark 108 and pass through the first wafer 105 again. Therefore, the first light L1 has a certain transmittance, for example, its wavelength belongs to the wavelength range that can pass through the wafer. Taking the silicon wafer as an example, the first light can be infrared light or rays with a wavelength greater than infrared light, which are collectively referred to as light in the embodiments of the present application. It can be understood that in order to obtain the first light L1 with the above-mentioned transmittance, the light source assembly 101 needs to provide the original light L0 with this characteristic.

[0099] It should be emphasized that the wafers to be measured may be the first wafer and the second wafer before being bonded together, or may be the first wafer and the second wafer that have been bonded together.

[0100] The wafer alignment measurement device provided in the embodiments of the present application, on the one hand, utilizes light with good penetrability relative to the first wafer 105 or the second wafer 107, allowing it to pass through the first wafer 105 and propagate to the second alignment mark 108 on the second wafer 107. This allows direct observation or measurement of whether the first alignment mark 106 and the second alignment mark 108 are aligned, simplifying the alignment identification steps and reducing measurement errors caused by separate observations. Secondly, by utilizing first light L1 and second light L2 with different polarization directions, selective transmission and reflection of the incident light and reflected light of the alignment mark (first alignment mark or second alignment mark) can be achieved. The imaging component only captures the reflected second light, which can enhance the imaging quality of the first moiré fringes and facilitate the extraction of alignment information. Thirdly, utilizing the first moiré fringes can amplify the deviations between the alignment marks, which is conducive to improving the accuracy of alignment measurement.

[0101] In some embodiments, as Figure 2 As shown, the alignment measurement device 100 further includes:

[0102] The data processing device 201 is connected to the imaging component 104 and is used to determine whether the first alignment mark and the second alignment mark are aligned according to the first moiré fringes and the preset second moiré fringes.

[0103] For the determined first alignment mark 106 and second alignment mark 108, a fixed moiré pattern corresponding to the alignment state can be obtained, namely, a preset second moiré pattern. The data processing device 201 may store the preset second moiré pattern, which can be obtained through pre-calibration or simulation. When the first moiré pattern captured by the imaging component matches the second moiré pattern, it indicates that the first and second alignment marks are aligned.

[0104] It is understandable that Figure 2 The data processing 201 shown distributed along the X-axis with the imaging component 104 is only for illustrative purposes, and the embodiment of the present application does not limit the specific location of the data processing component.

[0105] In some embodiments, as Figure 3 As shown, the imaging assembly includes a tube lens 301 and an image sensor 302;

[0106] The tube lens 301 is located between the beam splitter 102 and the image sensor 302 and is used to converge the second light passing through the beam splitter 102 ;

[0107] The image sensor 302 is used to collect the first moiré fringes formed by the second light.

[0108] The cylindrical lens 301 converges the second light beam passing through the beam splitter 102 and focuses the second light beam onto the imaging plane, so that a clear image of the first moiré fringe can be formed on the image sensor 302 .

[0109] The specific type of the image sensor 302 can be reasonably selected according to the wavelength band of the original light L0 emitted by the light source assembly 101 to further improve the sensitivity and response capability of the image sensor 302 under the light condition.

[0110] In some embodiments, continue to refer to Figure 3 , the alignment measurement device 100 further includes:

[0111] The objective lens assembly 303 is located between the polarizer 103 and the first wafer 105 . The objective lens assembly 303 is used to focus the light to a preset position between the first alignment mark and the second alignment mark.

[0112] That is, the focal plane of objective lens assembly 303 can be set at a preset position between first alignment mark 106 and second alignment mark 108, such that in the third direction (positive Z-axis direction), first alignment mark 106 and second alignment mark 108 are both within the depth of field of objective lens assembly 303. Here, the preset position can be located anywhere between the positions of first alignment mark 106 and second alignment mark 108. In actual applications, the position with the best imaging effect can be found through multiple experiments and used as the preset position.

[0113] In this way, the first light L1 can be reflected on the surfaces of the first alignment mark 106 and the second alignment mark 108 through one-time focusing, and corresponding first moiré fringes can be obtained.

[0114] In some embodiments, as Figure 4 As shown, the light source assembly 101 includes a laser emitter 401;

[0115] The laser emitter 401 is used to emit an original light L0 having a wavelength greater than that of visible light.

[0116] Light within the visible light range (e.g., wavelengths less than 780nm) cannot penetrate silicon wafers, making it ineffective for direct observation or measurement of stacked silicon wafers using visible light. Generally speaking, the longer the wavelength of the original light L0, the greater its penetrating properties. By extending the wavelength of the original light to the infrared range (e.g., wavelengths greater than 1200nm), the light can propagate to the surfaces of the first and second alignment marks, enabling direct observation of the wafer's alignment status. Furthermore, greater penetrating properties allow more light to be reflected by the alignment marks, improving the imaging quality of the imaging component.

[0117] In some embodiments, the light source assembly 101 may further include a beam expander, which may be positioned between the laser emitter 401 and the beam splitter 102 to modulate the light into parallel light. Parallel light can provide uniform illumination, increase brightness distribution consistency, and improve the imaging quality of the first moiré fringe.

[0118] Furthermore, filters, polarizers, and half-wave plates can be added between the beam expander and the beam splitter to adjust the bandwidth, polarization, and energy of the parallel light, respectively. Parallel light can better cooperate with components such as filters, polarizers, and half-wave plates, further ensuring that the performance of these optical components is fully utilized.

[0119] It is understandable that the embodiments of the present application do not limit the specific positions of components such as the laser emitter, beam expander, filter, polarizer and half-wave plate, as long as the first light L1 reflected by the beam splitter 102 propagates along the first direction.

[0120] In some embodiments, as Figure 5A As shown, the first alignment mark 106 includes a plurality of first grating stripes 501 arranged along the fourth direction, or as shown in FIG. Figure 5B As shown, the first alignment mark 106 includes a plurality of first grating ring patterns 502 in concentric circles; wherein the fourth direction is parallel to the surface of the first wafer;

[0121] And / or, the second alignment mark includes a plurality of second grating stripes arranged along a fifth direction, or the second alignment mark includes a plurality of second grating rings in the form of concentric circles; wherein the fifth direction is parallel to the surface of the second wafer.

[0122] The plurality of first grating stripes 501 arranged along the fourth direction can be used to achieve wafer alignment in the fourth direction. The plurality of second grating stripes arranged along the fifth direction can be used to achieve wafer alignment in the fifth direction. It should be noted that the first grating stripes and the second grating stripes in the aligned state are arranged in the same direction, that is, the fourth direction is parallel to the fifth direction.

[0123] In some embodiments, as Figure 6 As shown, in order to achieve alignment of the first wafer and the second wafer on the XOY plane, a set of first grating stripes can be set on the first wafer along the X-axis and Y-axis directions respectively. Similarly, a set of second grating stripes can be set on the second wafer along the X-axis and Y-axis directions respectively. It should be noted that the arrangement along the X-axis and Y-axis directions is only for illustration. The embodiment of the present application does not limit the arrangement direction of the two sets of grating stripes, as long as their arrangement directions are not parallel to each other. Moreover, the two sets of first grating stripes along different directions do not affect each other and can be set separately.

[0124] In some embodiments, along the fourth direction, the first grating stripes are arranged according to a first period P1;

[0125] Along the fifth direction, the second grating stripes are arranged according to the second period P2;

[0126] The absolute value of the difference between the first period P1 and the second period P2 is greater than 0 and less than or equal to a preset first threshold.

[0127] The first threshold value can be determined based on the first period or the second period. For example, the first threshold value can be determined as half of the first period. In practical applications, the difference between the first period and the second period can be reduced to increase the spacing of the first moiré fringes and improve the resolution of the alignment measurement.

[0128] Figure 7 Schematic diagram showing the comparison between the first alignment mark and the second alignment mark. Figure 7As shown, the first grating stripes 501 are rectangular with a width a1. Multiple first grating stripes 501 are arranged along the positive direction of the X-axis. The distance between any two adjacent first grating stripes 501 is b1. Therefore, the first period P1 is the sum of the width a1 and the distance b1. Similarly, the second grating stripes 503 are rectangular with a width a2. Multiple second grating stripes 503 are arranged along the positive direction of the X-axis. The distance between any two adjacent second grating stripes 503 is b2. Therefore, the second period P2 is the sum of the width a2 and the distance b2. The absolute value of the difference between the first period P1 and the second period P2 is |a1+b1-a2-b2|.

[0129] Figure 8 The first moiré fringes are shown in different alignment states, with (a) showing the first moiré fringes when the first and second alignment marks are aligned, and (b) showing the first moiré fringes when the first and second alignment marks are misaligned. When two grating fringes with similar periods and slight deviations overlap, namely, when the first alignment mark 106 and the second alignment mark 108 overlap, the period deviation produces first moiré fringes with dark fringes 801 of varying widths. If the two grating fringes are relatively offset, the bright and dark positions of the first moiré fringes (e.g., the position of dark fringes 801) will also change. By comparing the measured first moiré fringes with the second moiré fringes in the aligned state, the relative offset and direction between the two grating fringes can be inferred.

[0130] In some embodiments, as Figure 9 As shown, along the first direction, there is a first distance Z1 between the first alignment mark 106 and the second alignment mark 108;

[0131] The difference between the width of the first grating stripes and the first distance is less than a preset second threshold; the difference between the width of the first grating ring pattern and the first distance is less than a preset third threshold;

[0132] and / or

[0133] The difference between the width of the second grating stripes and the first distance is smaller than the second threshold; the difference between the width of the first grating ring pattern and the first distance is smaller than the third threshold.

[0134] The second threshold can be determined based on the width or first period of the grating stripes (the first grating stripes or the second grating stripes), and the third threshold can be determined based on the width or period of the grating rings (the first grating rings or the second grating rings). For example, the first distance Z1 and the width of the grating stripes can be of the same order of magnitude, or the first distance Z1 and the width of the grating rings can be of the same order of magnitude. Alternatively, the difference between the width of the first grating stripes and the first distance Z1 can be less than the first period P1. For example, if the first distance Z1 and the width of the grating stripes are both in the micron range, the light reflected by the first alignment mark and the second alignment mark can be considered zero-order diffracted light, reducing the influence of the first moiré fringe on the Talbot effect, total internal reflection, and diffraction effects. The Talbot effect refers to the phenomenon in which a grating forms a self-image at a specific distance. Total internal reflection refers to the phenomenon in which light is completely reflected back into the denser medium when the incident angle is greater than the critical angle when light is incident from a denser medium to an optically less dense medium. The diffraction effect refers to the phenomenon that light deviates from a straight line when encountering an obstacle or passing through a slit.

[0135] In some embodiments, the material of the first grating stripes and / or the material of the second grating stripes include a metal material.

[0136] Similarly, the material of the first grating ring pattern and / or the material of the second grating ring pattern also includes metal material.

[0137] Metal materials like copper and aluminum have excellent reflective properties. For example, aluminum's reflectivity can exceed 90% in the infrared range. Gratings with excellent reflective properties can significantly reduce light energy loss and further improve alignment measurement performance.

[0138] The present application also provides the following embodiments:

[0139] like Figure 10As shown, a first wafer 105 and a second wafer 107 are both placed on a sample stage 1001 of an alignment measurement apparatus 100. The wafer alignment measurement apparatus 100 determines whether the first and second wafers are aligned based on a first alignment mark 106 on the first wafer 105 and a second alignment mark 108 on the second wafer 107. Specifically, the light source assembly 101 of the wafer alignment measurement apparatus 100 provides infrared light. This infrared light propagates along the negative X-axis to the beam splitter 102, which then splits the infrared light into a first linearly polarized light beam having a first polarization direction (i.e., a first light beam L1 having a first polarization direction) and a second linearly polarized light beam having a second polarization direction. The plane of the beam splitter 102 forms a 45° angle with the XOY plane. The first light beam L1 is reflected by the beam splitter 102 and propagates along the negative Z-axis to the polarizer. This means that the first angle between the original light beam L0 incident on the beam splitter and the first light beam L1 is 90°. The polarizing element is a quarter-wave plate 113. After passing through the quarter-wave plate 113, the first light ray L1 having a first polarization direction becomes the first circularly polarized light C1. After being reflected by the first alignment mark 106 and the second alignment mark 108, the first circularly polarized light C1 and the second circularly polarized light C2 travel in opposite directions. Because the handedness of the circularly polarized light is reversed after reflection, i.e., the handedness of the first circularly polarized light C1 and the second circularly polarized light C2 are opposite, the second circularly polarized light C2 propagates upward along the positive direction of the Z axis and passes through the quarter-wave plate 113, becoming the second light ray L2 having a second polarization direction. The first and second polarization directions are perpendicular to each other. The second light ray L2 having the second polarization direction can smoothly pass through the beam splitter 102 and, after being focused by the tube lens 301, is captured by the image sensor 302.

[0140] The data processing component 201 is connected to the image sensor 302, and analyzes and compares the first moiré fringe captured by the image sensor 302 with the preset second moiré fringe to determine the offset between the first alignment mark 106 and the second alignment mark 108. For example, Figure 11 As shown, a measured signal curve is extracted based on the first moiré fringe, and the offset between the first alignment mark 106 and the second alignment mark 108 can be determined by comparing the measured signal curve with the theoretical signal curve corresponding to the second moiré fringe.

[0141] Specifically, by comparing the measured signal curve corresponding to the first moiré fringe with the theoretical signal curve corresponding to the second moiré fringe, the offset Δ at the peak position of the two curves is obtained, where the sign of the offset Δ is defined by the offset direction. The actual translation offset δ between the first alignment mark 106 and the second alignment mark 108 can then be determined using the following magnification formula (1):

[0142] δ=Δ / (M f *Mopt )(1)

[0143] Among them, M opt Indicates the magnification of the imaging component, M f Indicates the moiré fringe magnification.

[0144] It should be noted that the imaging component magnification M opt It includes the image processing magnification and the magnification of the optical lens group such as the objective lens assembly 303 and the tube lens 301. Moire fringe magnification M f It refers to the magnification of the moiré fringe displacement relative to the relative displacement between grating fringes.

[0145] The number of sampling points N on a single side and the field of view FOV of the image sensor 302 can be determined according to the following equations (2) and (3), respectively:

[0146] N=M opt / η CCD (2)

[0147] FOV=W / η CCD (3)

[0148] Among them, η CCD represents the resolution of the image sensor 302 , and W represents the image plane width of the image sensor 302 .

[0149] In practical applications, the moiré fringe magnification M can be controlled by adjusting specific parameters of the first alignment mark 106 and the second alignment mark 108, such as adjusting the difference between the first period P1 of the first grating stripes and the second period P2 of the second grating stripes. f Specifically, the moiré fringe magnification M f It can be determined according to the following formula (4):

[0150] M f =(P1+P2) / (P1-P2)(4)

[0151] At this time, the displacement resolution η of the alignment measurement device can be calculated based on the magnification of the imaging component M. opt , Moiré fringe magnification M f and the resolution η of the image sensor 302 CCD Specifically, the displacement resolution η of the alignment measurement device can be determined according to the following formula (5):

[0152] η=η CCD / (M f *M opt )(5)

[0153] In addition, the effective alignment range of the first moiré fringe, that is, the maximum displacement range that can achieve precise alignment, can also be controlled by adjusting the first period P1 and the second period P2. Specifically, the effective alignment range R can be determined according to the following formula (6):

[0154] R=±P F / 4=±(P1*P2) / (4(P1-P2))(6)

[0155] Based on the same inventive concept, the present application provides a wafer alignment measurement method, such as Figure 12 As shown, the wafer alignment measurement method includes the following steps:

[0156] Step S101: using a light source assembly to provide original light propagating along a second direction.

[0157] Step S102 : After being reflected by the beam splitter, the original light propagates along a first direction through the polarizer to a first alignment mark on the first wafer, and then propagates through the first wafer to a second alignment mark on the second wafer.

[0158] Among them, the light reflected by the beam splitter is the first light with a first polarization direction; the light reflected by the first alignment mark and the second alignment mark is the second light, and the second light has a second polarization direction after passing through the polarizer; the second polarization direction is different from the first polarization direction.

[0159] Step S103: using an imaging component to collect first moiré fringes formed by the second light having the second polarization direction after passing through the beam splitter.

[0160] The first moiré fringe is used to determine whether the first alignment mark and the second alignment mark are aligned.

[0161] The imaging component, the beam splitter and the polarizer are sequentially arranged along a first direction, and the light source component and the beam splitter are arranged along a second direction; the first direction and the second direction have a first angle.

[0162] In some embodiments, the alignment measurement method further comprises the following steps:

[0163] Determining a translation offset between the first alignment mark and the second alignment mark according to the first moiré fringe and a preset second moiré fringe;

[0164] The first wafer and / or the second wafer are horizontally moved according to the translation offset so that the first alignment mark is aligned with the second alignment mark.

[0165] Since the movement amount and movement direction of the first moiré fringe have a strict corresponding relationship with the translation offset amount and offset direction between the first alignment mark and the second alignment mark, according to the first moiré fringe and the preset second moiré fringe, it is possible to determine how to adjust the direction and movement distance of the wafer to be moved so that the first alignment mark and the second alignment mark are aligned.

[0166] In some embodiments, the alignment measurement method further comprises the following steps:

[0167] determining an offset angle between the first alignment mark and the second alignment mark according to a normal vector of the first alignment mark and a normal vector of the second alignment mark;

[0168] The horizontal rotation angle of the first wafer and / or the second wafer is adjusted according to the offset angle so that the first alignment mark and the second alignment mark are parallel to the same plane.

[0169] Based on the same inventive concept, the present application provides a bonding device, such as Figure 13 As shown, the bonding device 200 includes any one of the above alignment measurement devices 100 and a control component 300,

[0170] The control component 300 is used to move the first wafer 105 and / or the second wafer 107 to be bonded according to the measurement information of the alignment measurement device 100 so that the first alignment mark 106 and the second alignment mark 108 are aligned.

[0171] It should be noted that manual alignment or automatic alignment can be performed based on the measurement information of the alignment measurement device, so that the first wafer and the second wafer meet the alignment accuracy requirements of the bonding connection.

[0172] In some embodiments, the control component 300 is connected to the data processing component 201 in the alignment metrology device 100 and moves the wafers to be bonded based on the measurement information output by the data processing component 201. This ensures that the first moiré fringe collected matches the preset second moiré fringe, i.e., the first alignment mark and the second alignment mark are aligned.

[0173] Based on the same inventive concept, the present application provides a semiconductor structure, such as Figure 14 As shown, the semiconductor structure 400 includes a first wafer 105;

[0174] The first wafer 105 includes a first alignment mark 106; the first alignment mark 106 includes a plurality of first grating stripes arranged along the fourth direction, or the first alignment mark 106 includes a plurality of first grating rings in concentric circles;

[0175] The first alignment mark 106 is used to reflect light together with the second alignment mark located on the second wafer to form a first moiré fringe; the first moiré fringe is used to determine whether the first alignment mark 106 and the second alignment mark are aligned.

[0176] For detailed descriptions of the first alignment mark 106 and the second alignment mark 108 , please refer to the above text and will not be repeated here.

[0177] In some embodiments, as FIG. 15A to FIG. 15B As shown, the first wafer 105 further includes a first silicon substrate 1501 and at least one first transmission layer 1502;

[0178] The first alignment mark 106 is located on a side of the first transmission layer 1502 close to the first silicon substrate 1501 ; or the first alignment mark 106 is located on a side of the first transmission layer 1502 away from the first silicon substrate 1501 ;

[0179] The transmittance of the first transmission layer 1502 to light is greater than or equal to a preset first transmittance;

[0180] The transmittance of the first silicon substrate 1501 to light is greater than or equal to a preset second transmittance.

[0181] If a highly reflective material, such as metal, is located above the first alignment mark in the direction of incident light (for example, along the first direction), the pattern generated by the alignment mark will be blocked. If a highly reflective material, such as metal, is located below the second alignment mark, excess reflected light will be generated, creating background noise. Providing a first transmissive layer above or below the first alignment mark ensures that no other metal wiring patterns are present above or below the first alignment mark, thereby preventing interference with the acquisition of the first moiré pattern.

[0182] It is understood that the light in the "light transmittance" refers to the light within the wavelength range of the original light. A first transmission layer can be provided on both the upper and lower sides of the first alignment mark 106.

[0183] In some embodiments, the first transmittance is greater than or equal to 85%; and / or the second transmittance is greater than or equal to 50%.

[0184] In some embodiments, as Figure 16A or Figure 16B As shown, the semiconductor structure 400 further includes a second wafer 107;

[0185] The first wafer 105 is bonded to the second wafer 107;

[0186] The second alignment mark 108 includes a plurality of second grating stripes arranged along the fifth direction, or the second alignment mark includes a plurality of second grating rings in the form of concentric circles.

[0187] In some embodiments, continue to refer to Figure 16A and Figure 16B The second wafer 107 further includes a second silicon substrate 1601 and at least one second transmissive layer 1602; the second alignment mark 108 is located on a side of the second transmissive layer 1602 close to the second silicon substrate 1601, or the second alignment mark 108 is located on a side of the second transmissive layer 1602 away from the second silicon substrate 1601;

[0188] The transmittance of the second transmission layer 1602 to light is greater than or equal to the first transmittance;

[0189] The transmittance of the second silicon substrate 1601 to light is greater than or equal to the second transmittance.

[0190] In some embodiments, after bonding, a first transmissive layer and / or a second transmissive layer are included between the first alignment mark and the second alignment mark. It is understood that in these bonded semiconductor structures, the patterns of the first alignment mark and the second alignment mark are not affected by the wafer bonding process, and alignment measurements can be performed based on the first alignment mark and the second alignment mark after bonding.

[0191] In other embodiments, the upper surface of the first alignment mark is the upper surface of the first wafer, and the upper surface of the second alignment mark is the upper surface of the second wafer. Figure 16B As shown, after bonding, the first alignment mark 106 and the second alignment mark 108 are in contact with each other.

[0192] In some embodiments, the first transmission layer includes a silicon dioxide material and / or a silicon nitride material.

[0193] Similarly, the second transmission layer includes silicon dioxide material and / or silicon nitride material.

[0194] Light can transmit through the silicon dioxide material and / or silicon nitride material to the surface of the first alignment mark or the second alignment mark. The transmittance of silicon dioxide and silicon nitride materials in the near-infrared range is better than that in the far-infrared range. Selecting near-infrared light as the source light can further improve the quality of the first moiré fringe.

[0195] It should be noted that silicon dioxide and / or silicon nitride are only used for exemplary purposes. The present invention does not limit the specific materials of the first transmission layer or the second transmission layer, as long as light can pass through them and reach the surfaces of the first alignment mark and the second alignment mark.

[0196] In some embodiments, the first wafer includes a plurality of first chip regions and scribe line regions between the first chip regions; and the first alignment mark is located in the scribe line regions.

[0197] Similarly, the second wafer includes a plurality of first chip regions and scribe line regions between the first chip regions; the second alignment mark is located in the scribe line region of the second wafer.

[0198] The dicing lane area is an area on a wafer (a first wafer or a second wafer) used to cut and separate chips. Setting the alignment mark (a first alignment mark or a second alignment mark) on the dicing lane area does not interfere with the device structure and function of the chip area of ​​the wafer, thereby ensuring the integrity and reliability of the chip area.

[0199] In addition, since the cutting street area can divide the wafer more evenly, multiple alignment marks (multiple first alignment marks or multiple second alignment marks) can be set in different cutting street areas. By analyzing the offset of the alignment marks located at different positions, the overall alignment status of the first wafer and the second wafer can be judged more accurately, further improving the alignment measurement accuracy of the wafer.

[0200] Furthermore, since both the first and second alignment marks are located within the scribe line area and are removed during the dicing process, there is no need to specifically consider the bonding quality of the wafer interface within the scribe line area. Even if both the first and second alignment marks are located on the wafer surface, they can be formed using different metal materials. In other words, even if the first and second alignment marks cannot be bonded during the bonding process, this will not affect the quality of the final chip or product.

[0201] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0202] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A wafer alignment measurement device, characterized in that: include: A light source assembly, a beam splitter, a polarizer, and an imaging assembly; wherein the imaging assembly, the beam splitter, and the polarizer are sequentially arranged along a first direction; the light source assembly and the beam splitter are arranged along a second direction; wherein the first direction and the second direction have a first angle; The light source assembly is used to provide original light propagating along the second direction; The beam splitter is used to reflect the original light based on the polarization direction; wherein the reflected light is a first light with a first polarization direction; The first light propagates along the first direction through the polarizer to a first alignment mark on the first wafer, and propagates through the first wafer to a second alignment mark on the second wafer; wherein the first wafer further includes a first silicon substrate and at least one first transmission layer; the first alignment mark is located on a side of the first transmission layer close to the first silicon substrate; or the first alignment mark is located on a side of the first transmission layer away from the first silicon substrate; the second wafer further includes a second silicon substrate and at least one second transmission layer; the second alignment mark is located on a side of the second transmission layer close to the second silicon substrate, or the second alignment mark is located on a side of the second transmission layer away from the second silicon substrate; The second light reflected by the first alignment mark and the second alignment mark has a second polarization direction after passing through the polarizer; the second polarization direction is different from the first polarization direction; The second light with a second polarization direction transmits the beam splitter along a third direction and propagates to the imaging component; wherein, the third direction is opposite to the first direction; the imaging component is used to collect the first moiré fringes formed by the second light; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned.

2. The alignment measurement device according to claim 1, wherein: Also includes: A data processing device is connected to the imaging component, and is used to determine whether the first alignment mark and the second alignment mark are aligned based on the first moiré fringes and preset second moiré fringes.

3. The alignment measurement device according to claim 1, wherein: The imaging assembly includes a tube lens and an image sensor; The cylindrical lens is located between the beam splitter and the image sensor, and is used to converge the second light passing through the beam splitter; The image sensor is used to collect the first moiré fringes formed by the second light.

4. The alignment measurement device according to claim 1, wherein: Also includes: An objective lens assembly is located between the polarizer and the first wafer, and is used to focus light to a preset position between the first alignment mark and the second alignment mark.

5. The alignment measurement device according to claim 1, wherein: The light source assembly includes a laser emitter; The laser emitter is used to emit the original light with a wavelength greater than that of visible light.

6. The alignment measurement device according to claim 1, wherein: The first alignment mark includes a plurality of first grating stripes arranged along a fourth direction, or the first alignment mark includes a plurality of first grating rings in the form of concentric circles; the fourth direction is parallel to the surface of the first wafer; And / or, the second alignment mark includes a plurality of second grating stripes arranged along a fifth direction, or the second alignment mark includes a plurality of second grating rings in the form of concentric circles; the fifth direction is parallel to the surface of the second wafer.

7. The alignment measurement device according to claim 6, wherein: Along the fourth direction, the first grating stripes are arranged according to a first period; Along the fifth direction, the second grating stripes are arranged according to a second period; An absolute value of a difference between the first period and the second period is greater than 0 and less than or equal to a preset first threshold.

8. The alignment measurement device according to claim 6, wherein: Along the first direction, there is a first distance between the first alignment mark and the second alignment mark; The difference between the width of the first grating stripes and the first distance is smaller than a preset second threshold; the difference between the width of the first grating rings and the first distance is smaller than a preset third threshold; and / or, The difference between the width of the second grating stripes and the first distance is smaller than the second threshold; the difference between the width of the first grating rings and the first distance is smaller than the third threshold.

9. The alignment measurement device according to claim 6, wherein: The material of the first grating stripes and / or the material of the second grating stripes include a metal material.

10. A bonding device, characterized in that: comprising the alignment measurement device and control assembly according to any one of claims 1 to 9, The control component is used to move the first wafer and / or the second wafer to be bonded according to measurement information of the alignment measurement device, so that the first alignment mark and the second alignment mark are aligned.

11. A semiconductor structure, characterized in that Performing alignment measurement using the alignment measurement device according to any one of claims 1 to 9; The semiconductor structure includes a first wafer and a second wafer bonded together; the first wafer includes a first alignment mark; the first alignment mark includes a plurality of first grating stripes arranged along a fourth direction, or the first alignment mark includes a plurality of first grating rings in concentric circles; The second wafer includes a second alignment mark; the second alignment mark includes a plurality of second grating stripes arranged along a fifth direction, or the second alignment mark includes a plurality of second grating rings in concentric circles; The first alignment mark is used to reflect light together with the second alignment mark to form a first moiré fringe; the first moiré fringe is used to determine whether the first alignment mark and the second alignment mark are aligned; The first wafer further includes a first silicon substrate and at least one first transmissive layer; the first alignment mark is located on a side of the first transmissive layer close to the first silicon substrate; or the first alignment mark is located on a side of the first transmissive layer away from the first silicon substrate; The second wafer further includes a second silicon substrate and at least one second transmission layer; the second alignment mark is located on a side of the second transmission layer close to the second silicon substrate, or the second alignment mark is located on a side of the second transmission layer away from the second silicon substrate.

12. The semiconductor structure according to claim 11, wherein: The transmittance of the first transmission layer to light is greater than or equal to a preset first transmittance; The transmittance of the first silicon substrate to light is greater than or equal to a preset second transmittance.

13. The semiconductor structure according to claim 12, wherein: The first transmittance is greater than or equal to 85%; and / or the second transmittance is greater than or equal to 50%.

14. The semiconductor structure according to claim 12, wherein: The transmittance of the second transmission layer to light is greater than or equal to the first transmittance; The transmittance of the second silicon substrate to light is greater than or equal to the second transmittance.

15. The semiconductor structure according to claim 11, wherein: The first transmission layer includes silicon dioxide material and / or silicon nitride material.

16. The semiconductor structure according to claim 11, wherein: The first wafer includes a plurality of first chip regions and a scribe line region between the first chip regions; the first alignment mark is located in the scribe line region.

17. A wafer alignment measurement method, characterized in that: include: Using the light source assembly to provide original light propagating along a second direction; After being reflected by the beam splitter, the original light propagates along a first direction through the polarizer to a first alignment mark on the first wafer, and then propagates through the first wafer to a second alignment mark on the second wafer. The first wafer further includes a first silicon substrate and at least one first transmission layer; the first alignment mark is located on a side of the first transmission layer close to the first silicon substrate; or the first alignment mark is located on a side of the first transmission layer away from the first silicon substrate; the second wafer further includes a second silicon substrate and at least one second transmission layer; the second alignment mark is located on a side of the second transmission layer close to the second silicon substrate, or the second alignment mark is located on a side of the second transmission layer away from the second silicon substrate. The light reflected by the beam splitter is a first light having a first polarization direction; the light reflected by the first alignment mark and the second alignment mark is a second light, and the second light has a second polarization direction after passing through the polarizer; the second polarization direction is different from the first polarization direction; collecting, using an imaging component, first moiré fringes formed by the second light having a second polarization direction after passing through the beam splitter; the first moiré fringes are used to determine whether the first alignment mark and the second alignment mark are aligned; The imaging component, the beam splitter and the polarizer are sequentially arranged along a first direction, and the light source component and the beam splitter are arranged along a second direction; the first direction and the second direction have a first angle.

18. The alignment measurement method according to claim 17, wherein: Also includes: determining a translation offset between the first alignment mark and the second alignment mark according to the first moiré fringe and a preset second moiré fringe; The first wafer and / or the second wafer are horizontally moved according to the translation offset so that the first alignment mark is aligned with the second alignment mark.

19. The alignment measurement method according to claim 17, wherein: Also includes: determining an offset angle between the first alignment mark and the second alignment mark according to a normal vector of the first alignment mark and a normal vector of the second alignment mark; The horizontal rotation angle of the first wafer and / or the second wafer is adjusted according to the offset angle, so that the first alignment mark and the second alignment mark are parallel to the same plane.

Images