Overlay measurement mark

Abstract

According to the overlay measurement mark, a plurality of first graphic mark groups and a plurality of second graphic mark groups are arranged in a one-to-one correspondence manner, and first graphic marks in each first graphic mark group correspond to second graphic marks in each second graphic mark group in a one-to-one correspondence manner; at least one part of the first graphic mark vertically maps and falls into the corresponding second graphic mark, at least the other part of the first graphic mark vertically maps to the outside of the corresponding second graphic mark, and the overlapped part of the first graphic mark and the second graphic mark is measured through the DBO machine table to obtain overlay error information; the non-overlapping part of the first graphic mark and the second graphic mark is measured through the IBO machine table to obtain front-layer information and current-layer information, then the front-layer information and the current-layer information are compared to obtain overlay error information, and the overlay measurement mark can achieve IBO overlay precision measurement and DBO overlay precision measurement respectively. Therefore, the area occupied by the overlay measurement mark on the scribing groove corresponding to the mask plate is saved.

Description

Technical Field

[0001] The utility model relates to the field of overlay alignment, in particular to an overlay measurement mark. Background Art

[0002] In semiconductor processes, in order to ensure that the final circuit can work properly, different photolithography graphic layers need to be precisely aligned during the photolithography process. The difference in alignment between different photolithography graphic layers is called overlay error by technicians in this field. The definition of overlay error is the planar distance between the centers of two-layer graphic structures. As the number of layers of integrated circuits continues to increase, multiple-pattern and multiple-exposure photolithography processes are widely used, and the overlay accuracy between circuit graphics formed in different steps is becoming increasingly important. The misalignment caused by excessive overlay error will cause the entire circuit to fail and be scrapped. Overlay error measurement equipment is used to ensure the correct alignment and placement of circuit graphics at different levels and circuit graphics on the same layer. Overlay error measurement is usually performed after each photolithography step.

[0003] Overlay error measurement includes optical microscopy imaging (IBO: Image Based Overlay) and optical diffraction imaging (DBO: Diffraction Based Overlay). Optical microscopy imaging equipment is more commonly used. The digital graphics of two layers of overlay target graphics are obtained through the optical microscopy system, and then the boundary position of each layer of graphics is located through the software algorithm, and the center position is further calculated to obtain the overlay error; the optical diffraction equipment irradiates a beam of monochromatic parallel light onto the gratings of different layers of overlay targets, and determines the error by measuring the uncertainty of the diffraction beam intensity.

[0004] As semiconductor manufacturing processes evolve to advanced process nodes, the area on the mask corresponding to the scribe groove will become smaller and smaller, while the various marks that need to be placed in the dividing groove will increase. In the semiconductor manufacturing process, when the mask is preparing two sets of IBO and DBO marks for measurement, the limited space on the mask corresponding to the scribe groove will result in not being able to place enough overlay marks. Utility Model Content

[0005] In order to solve the above technical problems, the technical solution of the utility model provides an overlay measurement mark to meet the use of two sets of different overlay error measurement marks IBO and DBO in semiconductor process flow, while saving the space of the corresponding scribe groove on the mask occupied by these two sets of overlay error measurement marks.

[0006] The technical solution of the utility model provides an overlay measurement mark for measuring the overlay offset between the current graphic layer and the previous graphic layer in the semiconductor lithography process. The overlay measurement mark includes:

[0007] A first set of engraved marks, set in the current graphic layer; the first set of engraved marks includes a plurality of first graphic mark groups, each of which includes a plurality of first graphic marks;

[0008] A second set of engraved marks, arranged on the previous graphic layer; the second set of engraved marks comprises a plurality of second graphic mark groups, each of which comprises a plurality of second graphic marks;

[0009] Among them, the multiple first graphic mark groups are arranged in one-to-one correspondence with the multiple second graphic mark groups, and the first graphic marks in each first graphic mark group and the second graphic marks in each second graphic mark group respectively correspond one-to-one, at least a part of the first graphic mark is vertically mapped to fall into the corresponding second graphic mark, and at least another part of the first graphic mark is vertically mapped outside the corresponding second graphic mark.

[0010] Optionally, the plurality of first graphic marks in the first graphic mark group are evenly spaced and arranged;

[0011] The plurality of second graphic marks in the second graphic mark group are evenly spaced and arranged.

[0012] Optionally, the first graphic mark is along a strip-shaped graphic, the portion of the first graphic mark vertically mapped into the corresponding second graphic mark is in the shape of a strip, and the width of the strip of the first graphic mark vertically mapped into the second graphic mark is smaller than the width of the strip of the second graphic mark.

[0013] Optionally, the length of the long strip of the first graphic mark vertically mapped into the second graphic mark is at least 5 μm-10 μm.

[0014] Optionally, the first set of engraved marks includes at least two first graphic mark groups, and the two first graphic mark groups are respectively arranged perpendicular to each other along a first direction and a second direction.

[0015] Optionally, the first set of engraved marks includes four first graphic mark groups, and adjacent first graphic mark groups are arranged perpendicular to each other along the first direction and the second direction respectively.

[0016] Optionally, the second engraved mark includes at least two second graphic mark groups, and the two second graphic mark groups are respectively arranged perpendicular to each other along the first direction and the second direction.

[0017] Optionally, the second set of engraved marks includes four second graphic mark groups, and adjacent first graphic mark groups are arranged perpendicular to each other along the first direction and the second direction respectively.

[0018] Optionally, the outline of the area occupied by the first overlay mark is located within the outline of the area occupied by the second overlay mark.

[0019] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects: in the photoresist coating method provided by the utility model,

[0020] In the overlay measurement mark provided by the present invention, the plurality of first graphic mark groups and the plurality of second graphic mark groups are arranged in one-to-one correspondence, and the first graphic mark in each first graphic mark group and the second graphic mark in each second graphic mark group correspond to each other one-to-one, at least a part of the first graphic mark is vertically mapped to fall into the corresponding second graphic mark, and at least another part of the first graphic mark is vertically mapped outside the corresponding second graphic mark. On the one hand, when the IBO measurement station measures the part of the first graphic mark vertically mapped to the part outside the corresponding second graphic mark, the overlay information of the previous layer and the current layer is obtained; on the other hand, when the DBO measurement station measures the part of the first graphic mark vertically mapped to fall into the corresponding second graphic mark, the overlay error information can be obtained. The overlay measurement mark provided by the present invention can realize both IBO overlay accuracy measurement and DBO overlay accuracy measurement, while saving the area occupied by the overlay measurement mark on the corresponding scribe groove of the mask. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] Figure 1 is a top view of an embodiment of an IBO;

[0023] Figure 2 is a top view of an embodiment of a DBO;

[0024] Figure 3 It is a top view of the overlay measurement mark provided by the technical solution of the utility model;

[0025] Figure 4 It is a cross-sectional view of a simple device with overlay measurement marks provided by the technical solution of the utility model;

[0026] Figure 5 A top view of a single graphic mark in the overlay measurement mark provided by the technical solution of the utility model;

[0027] Figure 6 The top view of the first engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 1 ;

[0028] Figure 7The top view of the first engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 2 ;

[0029] Figure 8 The top view of the second engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 1 ;

[0030] Fig. 9 The top view of the second engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 2 ;

[0031] Fig.10 It is a top view of the first overlay mark combined with the second overlay mark in the overlay measurement mark provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the utility model. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] As described in the background art, when the prior art uses IBO and DBO for overlay measurement, there is a problem that the space of the mask corresponding to the scribe groove is seriously insufficient.

[0034] Figure 1 is a top view of an embodiment of an IBO.

[0035] Please refer to Figure 1, IBO specifically includes 4 groups of first graphic mark groups 100, which are respectively arranged in 4 different quadrants in the XY coordinate system, and the first graphic mark groups 100 in adjacent quadrants are perpendicular to each other along the X direction and the Y direction. Each first graphic mark group 100 includes a plurality of first front-layer graphic marks 101 and one-to-one corresponding first current-layer graphic marks 102, the first front-layer graphic marks 101 are used to represent the graphic marks set in the previous graphic layer, and the first current-layer graphic marks 102 are used to represent the graphic marks set in the current graphic layer. If the first graphic mark group 100 is arranged along the X direction, each first front-layer graphic mark 101 and the corresponding first current-layer graphic mark 102 in the first graphic mark group 100 are arranged non-overlappingly along the X direction; if the first graphic mark group 100 is arranged along the Y direction, each first front-layer graphic mark 101 and the corresponding first current-layer graphic mark 102 in the first graphic mark group 100 are arranged non-overlappingly along the Y direction. The first front layer graphic marks 101 in the first graphic mark group 100 are evenly spaced, and the first front layer graphic marks 101 and the first current layer graphic marks 102 are made of different materials. The images displayed under the optical microscope have light and dark differences. The working principle of using IBO for overlay measurement is based on image recognition technology. The measuring machine will convert the detected light and dark images into uneven signals. By analyzing the signals of the previous graphic layer and the current graphic layer respectively, the coordinates of the front and rear layer overlay marks are obtained, and then the front and rear layer overlay offset is calculated based on the coordinates.

[0036] In order to meet the demand for measuring higher overlay accuracy, the industry has developed a DBO measurement mark to measure overlay error.

[0037] Figure 2 is a top view of an embodiment of a DBO.

[0038] Please refer to Figure 2, DBO specifically includes 4 groups of second graphic mark groups 200, and the 4 groups of second graphic mark groups 200 are respectively arranged in 4 different quadrants in the XY coordinate system, and the second graphic mark groups 200 in adjacent quadrants are perpendicular to each other along the X direction and the Y direction. Each second graphic mark group 200 includes a number of second front layer graphic marks 201 and a one-to-one corresponding second current layer graphic mark 202, and each second current layer graphic mark 202 is vertically mapped into the corresponding second front layer graphic mark 201, so that the second front layer graphic mark 201 contains the corresponding second current layer graphic mark 202. Each second current layer graphic mark 202 is specifically a transmission grating, and each second front layer graphic mark 201 is specifically a reflection grating. The working principle of using DBO for overlay measurement is based on the reflected light interference technology. If the centers of the transmission grating and the reflection grating coincide with each other without offset, the intensities of the +1 order light and the -1 order light in the reflection grating are completely equal. On the contrary, it means that the centers of the two gratings are not completely overlapped, so that the intensities of the +1-order light and -1-order light in the reflection grating are different. Based on the above principle, technicians in this field will deliberately design a series of overlay marks with different degrees of offset between the current layer and the previous layer to find the relationship curve between the intensity difference between the +1-order light and the -1-order light and the overlay offset of the previous and next layers. In subsequent measurements, the corresponding overlay offset can be calculated based on the measured intensity difference and the relationship curve, and finally the overlay between the previous and next layers can be compensated based on the obtained overlay offset.

[0039] Overlay measurement by DBO is superior to overlay measurement by IBO in terms of sensitivity, accuracy and even measurement speed. However, to ensure the high reliability of overlay measurement by DBO, it is necessary to limit the overlay offset to a smaller range, which is usually 10nm to 20nm. Once the overlay offset exceeds this range, overlay measurement by DBO will be extremely unreliable. This principle is common knowledge in the field and will not be repeated here.

[0040] In actual applications, for example, when a product is tested for the first time, the overlay offset of the product wafer is usually large because various overlay-related parameters are not optimized. The lithography process in the wafer manufacturing plant will first measure the IBO mark, obtain the approximate overlay data, and then fill it into the lithography machine. After removing the exposed photoresist of the product wafer, the host machine with optimized parameters will be used for re-lithography. The overlay offset of the re-run product wafer is very small (for advanced lithography machines, this offset is usually no more than 10nm) because the overlay parameters have been optimized, and it has completely entered the high reliability and high precision range of DBO. At this time, the DBO measurement machine will be used to re-measure the overlay error, and more accurate data will be obtained to further optimize the parameters of the lithography host machine, so that the overlay accuracy of the lithography process is optimal. When the previous graphic layer and the current graphic layer are overlaid for the first time, because various overlay parameters have not been optimized, the overlay offset of the previous graphic layer and the current graphic layer will usually exceed 60nm. Therefore, the staff in this field will first use IBO to perform overlay measurement on the previous graphic layer and the current graphic layer to obtain the corresponding overlay offset. Due to the different working principles, IBO overlay accuracy measurement requires the front and rear layer overlay marks to be placed horizontally, while DBO overlay accuracy measurement requires the front and rear layer overlay marks to be placed vertically, so the two types of marks cannot be mixed, and it is necessary to set IBO and DBO on the corresponding scribe grooves of the mask at the same time. As the process evolves, more and more various marks are placed on the scribe grooves corresponding to the mask, and the scribe groove space becomes more and more precious. When using IBO overlay accuracy measurement and DBO overlay accuracy measurement at the same time, the limited space of the mask corresponding to the scribe groove will result in an inability to place enough overlay marks.

[0041] The inventor of the present application takes the above problems existing in the prior art as a starting point and proposes a new overlay measurement mark, which is used to measure the overlay offset between the current graphic layer NU and the previous graphic layer BD in the semiconductor lithography process.

[0042] Figure 3 It is a top view of the overlay measurement mark provided by the technical solution of the utility model. Figure 4 It is a simple device cross-sectional view of the overlay measurement mark along the first direction provided by the technical solution of the utility model.

[0043] Please refer to Figure 3 and Figure 4 The overlay measurement mark provided by the technical solution of the utility model includes:

[0044] A first set of engraved marks, set in the current graphic layer NU; the first set of engraved marks includes a plurality of first graphic mark groups 10, and each first graphic mark group 10 includes a plurality of first graphic marks 11;

[0045] A second set of engraved marks, arranged on the previous graphic layer BD; the second set of engraved marks comprises a plurality of second graphic mark groups 20, each of the second graphic mark groups 20 comprises a plurality of second graphic marks 21;

[0046] Among them, the multiple first graphic mark groups 10 are arranged in one-to-one correspondence with the multiple second graphic mark groups 20, and the first graphic mark 11 in each first graphic mark group 10 and the second graphic mark 21 in each second graphic mark group 20 respectively correspond one-to-one, at least a part of the first graphic mark 11 is vertically mapped to fall into the corresponding second graphic mark 21, and at least another part of the first graphic mark 11 is vertically mapped outside the corresponding second graphic mark 21.

[0047] The above overlay measurement marks provided by the technical solution of the utility model can realize the 1BO overlay accuracy measurement and the DBO overlay accuracy measurement, and at the same time save the area occupied by the overlay measurement marks on the corresponding scribe grooves of the mask. The specific principle is:

[0048] Through the overlay measurement mark provided by the technical solution of the utility model, on the one hand, when the 1BO measurement platform measures the portion of the first graphic mark vertically mapped to the portion outside the corresponding second graphic mark, the overlay information of the previous layer and the current layer is obtained; on the other hand, when the DBO measurement platform measures the portion of the first graphic mark vertically mapped to the portion corresponding to the second graphic mark, the overlay error information can be obtained. Therefore, the overlay measurement mark provided by the utility model can realize both IBO overlay accuracy measurement and DBO overlay accuracy measurement, while saving the area occupied by the overlay measurement mark on the corresponding scribe groove of the mask.

[0049] The specific structure of the overlay measurement mark provided by the technical solution of the utility model is described in detail below:

[0050] Please refer to Figure 3 As a specific implementation, the plurality of first graphic marks 11 in the first graphic mark group 10 are evenly spaced and arranged;

[0051] The plurality of second graphic marks 21 in the second graphic mark group 20 are evenly spaced. Specifically, the first graphic mark 11 and the second graphic mark 21 are made of different materials, so that the first graphic mark 11 and the second graphic mark 21 can show a difference in light and dark under an optical microscope.

[0052] Figure 5 For a top view of a single graphic mark in the overlay measurement mark provided by the technical solution of the utility model, please refer to Figure 3 and Figure 5As a specific implementation, the first graphic mark 11 is in a strip-shaped shape, and the portion of the first graphic mark 11 vertically mapped and falling into the corresponding second graphic mark 21 is also in a strip-shaped shape. The area where the first graphic mark 11 vertically maps and falls into the corresponding second graphic mark 21 and overlaps with the second graphic mark 21 is set as a first area 31, and the area where the first graphic mark 11 vertically maps to the outside of the corresponding second graphic mark 21 and does not overlap with the second graphic mark 21 is set as a second area 32. The length of the first graphic mark 11 in the first area 31 along the first direction D1 is less than the length of the first graphic mark 11 as a whole along the first direction D1, so as to ensure that the first graphic mark 11 and the second graphic mark 21 in the second area 32 can be used as IBO. The length of the first graphic mark 11 along the second direction D2 in the first area 31 is less than the length of the second graphic mark 11 along the second direction D2 in the first area 31, and the length of the first graphic mark 11 along the first direction D1 in the first area 31 is at least 5 μm to 10 μm, so as to ensure that the first graphic mark 11 and the second graphic mark 21 in the first area 31 can be used as DBO. Of course, the length of the first graphic mark 11 along the first direction D1 in the first area 31 can be selected according to actual needs and is not limited here.

[0053] Figure 6 The top view of the first engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 1 .

[0054] Please refer to Figure 6 As a specific implementation, the first set of engraved marks includes at least two first graphic mark groups 10, and the two first graphic mark groups 10 are respectively arranged perpendicular to each other along the first direction D1 and the second direction D2.

[0055] Figure 7 The top view of the first engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 2 .

[0056] Please refer to Figure 7 As a specific implementation, the first set of engraved marks includes four first graphic mark groups 10, and adjacent first graphic mark groups 10 are respectively arranged perpendicular to each other along the first direction D1 and the second direction D2.

[0057] Of course, the number of the first graphic mark group 10 included in the first set of engraved marks may include other numbers besides two and four, such as six, eight or ten, etc. The specific number can be selected according to needs and is not limited here.

[0058] Figure 8 The top view of the second engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 1 .

[0059] Please refer to Figure 8 The second set of engraved marks includes at least two second graphic mark groups 20, and the two second graphic mark groups 20 are respectively arranged perpendicular to each other along the first direction D1 and the second direction D2.

[0060] Fig. 9 The top view of the second engraved mark in the engraved measurement mark provided by the embodiment of the utility model Figure 2 .

[0061] Please refer to Fig. 9 The second set of engraved marks includes four second graphic mark groups 20, and adjacent second graphic mark groups 20 are arranged perpendicular to each other along the first direction D1 and the second direction D2.

[0062] Of course, the number of the second graphic mark group 20 included in the second set of engraved marks may include other numbers besides two and four, such as six, eight or ten, etc. The specific number can be selected according to needs and is not limited here.

[0063] It should be noted that the number of first graphic mark groups 10 included in the first overlay mark needs to correspond to the number of second graphic mark groups 20 included in the second overlay mark. For example, if the first overlay mark includes two first graphic mark groups 10, the second overlay mark also needs to include two second graphic mark groups 20. In addition, the number of first graphic marks 11 included in the first graphic mark group 10 also needs to correspond to the number of second graphic marks 21 included in the second graphic mark group 20.

[0064] Fig.10 It is a top view of the first overlay mark combined with the second overlay mark in the overlay measurement mark provided by an embodiment of the utility model.

[0065] Please refer to Fig.10As a specific implementation, the outline of the area occupied by the first set of engraving marks 1 is located within the outline of the area occupied by the second set of engraving marks 2. That is, the first set of engraving marks 1 of the front layer surrounds the second set of engraving marks 2 of the current layer. For the same semiconductor process, the same semiconductor process referred to here means that for the production of a chip of a product, multiple masks and hundreds or thousands of process flows may be required on a wafer; before the production begins, the alignment rules between layers have been set, specifically which previous layer the current layer is aligned with. If the alignment of two layers is based on the alignment mark of the front layer exemplified in this embodiment, the first set of engraving marks is on the periphery; when the layer is engraved, the second set of engraving marks is surrounded by the first set of engraving marks. In the same semiconductor process, the setting of the alignment marks of the other two layers also follows the second set of engraving marks being surrounded by the first set of engraving marks. Alternatively, the second set of engraving marks can surround the first set of engraving marks, and in the same semiconductor process, the engraving marks between the other two layers also follow the rule that the second set of engraving marks surround the first set of engraving marks.

[0066] Please refer to Figure 3 and Figure 5 , taking the case where the first graphic mark 11 is set as a first pattern and the second graphic mark 21 is set as a second pattern as an example, the process of overlaying the overlay measurement mark provided by the technical solution of the utility model is described:

[0067] Generally, the first pattern of the second area 32 is first detected by an IBO measuring machine to obtain the first information of the previous graphic layer BD. The second pattern of the second area 32 is detected by an IBO measuring machine to obtain the second information of the current graphic layer NU. The first information and the second information are compared to obtain the first overlay offset information. After obtaining the first overlay offset information, the first overlay offset information is recorded into the lithography host station, and the overlay offset data measured by IBO is used to compensate the lithography process in the corresponding process of the product by the lithography process host station, so that the product is compensated in this lithography process.

[0068] When the overlay accuracy is measured for the photolithography process of the compensated product, the first pattern and the second pattern in the first area 31 can be measured by the DBO measuring machine to obtain second overlay offset information with higher accuracy. After obtaining the second overlay offset information, the second overlay offset information is recorded in the photolithography process host machine, and the photolithography process of the product is compensated with higher accuracy based on the overlay offset data measured by the DBO measuring machine, thereby achieving the purpose of optimizing the photolithography process corresponding to the product.

[0069] In summary, the overlay measurement mark provided by the present invention is set by making the multiple first graphic mark groups correspond to the multiple second graphic mark groups one by one, and the first graphic mark in each first graphic mark group and the second graphic mark in each second graphic mark group correspond to each other one by one, at least a part of the first graphic mark is vertically mapped to fall into the corresponding second graphic mark, and at least another part of the first graphic mark is vertically mapped outside the corresponding second graphic mark. On the one hand, when the IBO measurement station measures the part of the first graphic mark vertically mapped to the outside of the corresponding second graphic mark, the overlay information of the previous layer and the current layer is obtained; on the other hand, when the DBO measurement station measures the part of the first graphic mark vertically mapped to fall into the corresponding second graphic mark, the overlay error information can be obtained. The overlay measurement mark provided by the present invention can realize both IBO overlay accuracy measurement and DBO overlay accuracy measurement, and at the same time saves the area occupied by the overlay measurement mark on the corresponding scribe groove of the mask.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An overlay measurement mark for measuring the overlay offset between a current graphic layer and a previous graphic layer in a semiconductor lithography process, characterized in that: The overlay metrology marks include: A first set of engraved marks, set in the current graphic layer; the first set of engraved marks includes a plurality of first graphic mark groups, each of which includes a plurality of first graphic marks; A second set of engraved marks, arranged on the previous graphic layer; the second set of engraved marks comprises a plurality of second graphic mark groups, each of which comprises a plurality of second graphic marks; Among them, the multiple first graphic mark groups are arranged in one-to-one correspondence with the multiple second graphic mark groups, and the first graphic marks in each first graphic mark group and the second graphic marks in each second graphic mark group respectively correspond one-to-one, at least a part of the first graphic mark is vertically mapped to fall into the corresponding second graphic mark, and at least another part of the first graphic mark is vertically mapped outside the corresponding second graphic mark.

2. The overlay measurement mark according to claim 1, characterized in that: The plurality of first graphic marks in the first graphic mark group are evenly spaced and arranged; The plurality of second graphic marks in the second graphic mark group are evenly spaced and arranged.

3. The overlay measurement mark according to claim 2, characterized in that: The first graphic mark is along a long strip graphic, the portion of the first graphic mark vertically mapped into the corresponding second graphic mark is in the shape of a long strip, and the width of the long strip of the first graphic mark vertically mapped into the second graphic mark is smaller than the width of the long strip of the second graphic mark.

4. The overlay measurement mark according to claim 3, characterized in that: The length of the long strip of the first graphic mark vertically mapped into the second graphic mark is at least 5 μm-10 μm.

5. The overlay measurement mark according to claim 2, characterized in that: The first set of engraved marks includes at least two first graphic mark groups, and the two first graphic mark groups are respectively arranged perpendicular to each other along a first direction and a second direction.

6. The overlay measurement mark according to claim 5, characterized in that: The first set of engraved marks includes four first graphic mark groups, and adjacent first graphic mark groups are arranged perpendicular to each other along the first direction and the second direction respectively.

7. The overlay measurement mark according to claim 2, characterized in that: The second engraved mark includes at least two second graphic mark groups, and the two second graphic mark groups are respectively arranged perpendicular to each other along the first direction and the second direction.

8. The overlay measurement mark according to claim 7, characterized in that: The second engraved mark includes four second graphic mark groups, and adjacent second graphic mark groups are arranged perpendicular to each other along the first direction and the second direction respectively.

9. The overlay measurement mark according to claim 1, characterized in that: The outline of the area occupied by the first overlay marks is located within the outline of the area occupied by the second overlay marks.

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