Mask plate

Abstract

The utility model provides a mask plate and a semiconductor device prepared by using the same, the mask plate comprises a main pattern and four groups of self-alignment mark pattern groups, the mask plate is provided with a first area and a second area, the second area is annularly arranged at the outer side of the first area, the first area is provided with the main pattern, and the second area is provided with the self-alignment mark pattern groups. All the self-alignment mark graph groups are arranged in the second area and arranged around the main graph at intervals, each self-alignment mark graph group comprises a first self-alignment mark graph, the first self-alignment mark graph comprises a first graph and a second graph, and the second graph is located on the inner side of the first graph; the first self-alignment mark pattern, the second self-alignment mark pattern, the first self-alignment mark pattern and the second self-alignment mark pattern are arranged at intervals, and the second self-alignment mark pattern only comprises the first pattern, so that the actual offset of the alignment mark can be fed back more accurately, the stability of the first layer of alignment mark can be ensured, and the reworking rate is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photolithography in semiconductor manufacturing, in particular to a mask plate. Background Art

[0002] At present, when preparing exposure wafers, the self-alignment mark used by the exposure machine when exposing the first layer is the same type as the overlay alignment (OVL) mark used when exposing the second layer (all layers other than the first layer are referred to as the second layer) (i.e., both are "U"-shaped overlay alignment marks), such as outer frame and inner frame models. The OVL mark is applicable to the second layer exposure compensation for the offset of the overlay alignment mark between the current layer and the previous layer, but is not applicable to the overlay alignment offset between adjacent units (shots) of the first layer. Specifically, the use of the OVL mark on the first layer will result in the overlay alignment compensation failing to achieve the target compensation, and will lead to the overlay alignment over-compensation problem. In addition, when establishing the first layer overlay configuration rule (recipe), connection errors are prone to occur.

[0003] Therefore, in order to enable the exposure of the first layer and the exposure of the second layer to share a set of overlay alignment models, a new first layer self-alignment mark is urgently needed. Utility Model Content

[0004] The utility model provides a mask plate and a semiconductor device prepared by using the mask plate, which can solve the problem of over-compensation of the overlay alignment offset of the current first layer.

[0005] In order to solve the above problems, the utility model provides a mask including a main pattern and four groups of self-alignment mark pattern groups, the mask having a first area and a second area, the second area is arranged outside the first area, the first area is provided with the main pattern, all the self-alignment mark pattern groups are arranged in the second area, and are arranged at intervals around the main pattern, each of the self-alignment mark pattern groups includes:

[0006] a first self-alignment mark pattern, the first self-alignment mark pattern comprising a first pattern and a second pattern, the second pattern being located inside the first pattern;

[0007] A second self-alignment mark pattern, wherein the first self-alignment mark pattern and the second self-alignment mark pattern are arranged alternately, and the second self-alignment mark pattern only includes the first pattern.

[0008] Optionally, the first graphic is formed into an L shape by two identical first rectangular strips, and the two first rectangular strips are arranged at an interval;

[0009] The second figure is formed into a rectangular ring by four identical second rectangular strips, and there are gaps between adjacent second rectangular strips.

[0010] Furthermore, the length of the first rectangular strip is greater than the length of the second rectangular strip.

[0011] Optionally, the four groups of self-alignment mark pattern groups are respectively:

[0012] A first self-alignment mark pattern group, located on the upper side of the first area;

[0013] A second self-alignment mark pattern group is located on the right side of the first region and is a pattern group obtained by rotating the first self-alignment mark pattern group 90° clockwise;

[0014] A third self-alignment mark pattern group is located at the lower side of the first region, parallel to and directly opposite to the first self-alignment mark pattern group, and is a pattern group obtained by rotating the second self-alignment mark pattern group 90° clockwise;

[0015] The fourth self-alignment mark pattern group is located on the left side of the first region, parallel to and opposite to the second self-alignment mark pattern group, and is a pattern group obtained by rotating the third self-alignment mark pattern group by 90° clockwise.

[0016] Furthermore, in the first self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the left side of the second self-alignment mark pattern, and the first pattern of the first self-alignment mark pattern covers the second pattern from the left side and the top side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the left side and the top side of the rectangular ring.

[0017] Furthermore, in the second self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the upper side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the upper side and the right side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the upper side edge and the right side edge of the rectangular ring.

[0018] Furthermore, in the third self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the right side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the right side and bottom side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the lower side and right side of a rectangular ring.

[0019] Furthermore, in the fourth self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart at the lower side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the left side and the bottom side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the left side and the bottom side of the rectangular ring.

[0020] Furthermore, the first self-alignment mark pattern of the first self-alignment mark pattern group is arranged opposite to the second self-alignment mark pattern of the third self-alignment mark pattern group, and the second self-alignment mark pattern of the first self-alignment mark pattern group is arranged opposite to the first self-alignment mark pattern of the third self-alignment mark pattern group.

[0021] Furthermore, the first self-alignment mark pattern of the second self-alignment mark pattern group is arranged opposite to the second self-alignment mark pattern of the fourth self-alignment mark pattern group, and the second self-alignment mark pattern of the second self-alignment mark pattern group is arranged opposite to the first self-alignment mark pattern of the fourth self-alignment mark pattern group.

[0022] Compared with the prior art, the utility model has the following unexpected technical effects:

[0023] The utility model provides a mask plate and a semiconductor device prepared by using the mask plate, the mask plate includes a main pattern and four groups of self-alignment mark pattern groups, the mask plate has a first area and a second area, the second area is arranged in a ring outside the first area, the first area is provided with the main pattern, all the self-alignment mark pattern groups are arranged in the second area, and are arranged at intervals around the main pattern, each of the self-alignment mark pattern groups includes: a first self-alignment mark pattern, the first self-alignment mark pattern includes a first pattern and a second pattern, the second pattern is located inside the first pattern; a second self-alignment mark pattern, the first self-alignment mark pattern and the second self-alignment mark pattern are arranged at intervals, and the second self-alignment mark pattern only includes the first pattern, which can more accurately feedback the actual offset of the overlay mark, can ensure the stability of the overlay alignment mark of the first layer, thereby reducing the rework rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the current first-layer mask;

[0025] Figure 2 To adopt Figure 1 A schematic diagram of the structure when the overlay alignment mark formed by exposure is offset in the y direction;

[0026] Figure 3 for Figure 2 An enlarged schematic diagram of the middle frame A;

[0027] Figure 4 It is a structural schematic diagram of the case where the overlay alignment mark formed by exposure using the second mask plate is offset in the y direction;

[0028] Figure 5 A schematic diagram of the structure of a mask provided in one embodiment of the utility model;

[0029] Figure 6 A schematic structural diagram of a first self-alignment mark pattern provided by an embodiment of the utility model;

[0030] Figure 7 A schematic structural diagram of a second self-alignment mark pattern provided by an embodiment of the utility model;

[0031] Figure 8 A schematic diagram of the structure of an overlay alignment mark formed by mask exposure using an embodiment of the utility model;

[0032] Fig. 9 It is a structural schematic diagram when the current first layer overlay alignment mark is offset;

[0033] Fig.10 It is a structural schematic diagram of a first layer when the overlay alignment mark of an embodiment of the utility model is offset.

[0034] in, Figure 1-Figure 4 Middle: 1-unit graphic area; 21-outer frame graphic; 22-inner frame graphic; 31-outer frame; 32-inner frame; B-center point of inner and outer frames; B1-center point of outer frame; B2-center point of inner frame; C1-center point of outer frame; C2-center point of inner frame;

[0035] Figure 5-Figure 10 Middle: 100-first area; 200-first self-alignment mark pattern group; 300-second self-alignment mark pattern group; 400-third self-alignment mark pattern group; 500-fourth self-alignment mark pattern group; 210-first self-alignment mark pattern; 211, 212-first rectangular strip; 213, 214, 2215, 216-second rectangular strip; 220-second self-alignment mark pattern; D1-center point of outer frame; D2-center point of inner frame; 210'-first self-alignment mark; 220'-second self-alignment mark. DETAILED DESCRIPTION

[0036] A mask of the utility model will be described in further detail below. The utility model will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the utility model are shown. It should be understood that those skilled in the art can modify the utility model described herein and still achieve the beneficial effects of the utility model. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the utility model.

[0037] For the sake of clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail because they would make the utility model confusing with unnecessary details. It should be recognized that in the development of any actual embodiment, a large number of implementation details must be made to achieve the developer's specific goals, such as changing from one embodiment to another according to the limitations of the relevant system or the relevant business. In addition, it should be recognized that such development work may be complex and time-consuming, but it is just routine work for those skilled in the art.

[0038] In order to make the purpose and features of the utility model more obvious and easy to understand, the specific implementation of the utility model is further described below in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are all in a very simplified form and use inaccurate ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0039] As described in the background technology, when the first layer and the second layer can share a set of overlay alignment models, the overlay alignment compensation of the current first layer self-alignment mark cannot reach the target compensation, resulting in over-compensation of the overlay alignment. The specific reasons are as follows:

[0040] like Figure 1 As shown, the current first-layer mask includes a unit pattern area 1 and a self-alignment mark area located outside the unit pattern area 1, and a self-alignment mark is arranged in the self-alignment mark area, and the self-alignment mark includes an outer frame pattern 21 and an inner frame pattern 22. The unit pattern area 1 is rectangular, and a main pattern is arranged therein, and each side of the unit pattern area 1 is provided with an outer frame pattern 21 and an inner frame pattern 22 arranged at intervals, and all the outer frame patterns 21 and the inner frame patterns 22 are arranged around the unit pattern area 1, and all the outer frame patterns 21 and the inner frame patterns 22 are arranged around the unit pattern area 1 periodically.

[0041] like Figure 2 As shown, the wafer is exposed using the first mask layer to form exposure units (shots) and overlay alignment marks located outside each exposure unit. At this time, each of the overlay alignment marks includes an outer frame 31 and an inner frame 32 located inside the outer frame 31, and the overlay alignment marks are located on the dicing road area between adjacent exposure units of the wafer.

[0042] like Figure 3 See also Figure 2In the overlay alignment mark shown in frame A, since both the outer frame 31 and the inner frame 32 are offset, when measuring the offset between adjacent exposure units, since the first layer is the first layer, the inner frame 32 and the outer frame 31 are both self-alignment marks of the current layer, then the offset of the overlay alignment mark of the first layer is the sum of the outer frame offset and the inner frame offset, that is, when measuring, it is necessary to measure the offset of the outer frame 31 (specifically, the outer frame center point B1) relative to the inner and outer frame center points B in the y direction, that is, the outer frame offset; at the same time, it is necessary to measure the offset of the inner frame 32 (specifically, the inner frame center point B2) relative to the inner and outer frame center points B in the y direction, that is, the inner frame offset. Therefore, the measurement result of the offset between adjacent exposure units in the first layer (that is, the measured offset) is the sum of the outer frame offset and the inner frame offset. However, for the first layer, the behavior of each exposure unit is consistent, which means that the measured offset measured by the self-alignment mark is not the compensation offset of the actual exposure unit, and the correct compensation offset should be the offset value of the self-alignment mark relative to the center point B of the inner and outer frames, that is, the compensation offset is half of the measured offset. For example, the inner frame 32 is offset downward by 10nm relative to the outer frame 31. When measuring the offset of the first layer, it is necessary to measure the downward offset of the outer frame 31 by 5nm relative to the center point B of the inner and outer frames, and at the same time, it is necessary to measure the upward offset of the inner frame 32 by 5nm relative to the center point B of the inner and outer frames. Finally, the inner frame 32 is offset downward by 10nm relative to the outer frame 31. At this time, the correct compensation offset is 5nm.

[0043] like Figure 4 As shown, in the second layer, the outer frame 41 is the self-alignment mark of the previous layer, and the inner frame 42 is the self-alignment mark of the current layer. Therefore, it is only necessary to measure the offset of the inner frame 42 relative to the outer frame 41. For example, the inner frame 42 is offset downward by 10nm relative to the outer frame 41, that is, the center point C2 of the inner frame is offset downward by 10nm relative to the center point C1 of the outer frame. Therefore, the offset of the inner frame 42 of this layer relative to the outer frame 41 is 10nm.

[0044] like Figure 5 As shown, based on the above analysis, in order to solve the above problems, the utility model provides a mask plate for forming exposure units (shots) on a wafer during first layer exposure, as well as self-alignment marks located around the exposure units and used between the exposure units.

[0045] The mask includes a main pattern and four groups of self-alignment mark pattern groups. The mask has a first area 100 and a second area. The second area is arranged outside the first area 100. The first area 100 is provided with a main pattern to form an exposure unit on the wafer during exposure. All the self-alignment mark pattern groups are arranged in the second area and are arranged at intervals around the exposure unit (i.e., the main pattern). In detail, the exposure unit is rectangular in shape, and a group of the self-alignment mark pattern groups is arranged outside each side of the exposure unit.

[0046] The four groups of self-alignment mark graphic groups are respectively a first self-alignment mark graphic group 200, a second self-alignment mark graphic group 300, a third self-alignment mark graphic group 400 and a fourth self-alignment mark graphic group 500. The first self-alignment mark graphic group 200 is located on the upper side of the first area 100, the second self-alignment mark graphic group 300 is located on the right side of the first area 100, the third self-alignment mark graphic group 400 is located on the lower side of the first area 100, and the fourth self-alignment mark graphic group 500 is located on the left side of the first area 100. The first self-alignment mark graphic group 200 and the third self-alignment mark graphic group 400 are parallel and opposite to each other, and the second self-alignment mark graphic group 300 and the fourth self-alignment mark graphic group 500 are parallel and opposite to each other.

[0047] Among them, the second self-alignment mark pattern group 300 is the pattern group obtained by rotating the first self-alignment mark pattern group 200 by 90° clockwise; the third self-alignment mark pattern group 400 is the pattern group obtained by rotating the first self-alignment mark pattern group 200 by 180°, that is, the third self-alignment mark pattern group 400 is the pattern group obtained by rotating the second self-alignment mark pattern group 300 by 90° clockwise; the fourth self-alignment mark pattern group 500 is the pattern group obtained by rotating the first self-alignment mark pattern group 200 by 270° clockwise, that is, the fourth self-alignment mark pattern group 500 is the pattern group obtained by rotating the third self-alignment mark pattern group 400 by 90° clockwise.

[0048] It should be noted that in Figure 5 In the figure, “up” refers to the direction of the third self-alignment mark pattern group 400 toward the first self-alignment mark pattern group 200, “down” refers to the direction of the first self-alignment mark pattern group 200 toward the third self-alignment mark pattern group 400, “left” refers to the direction of the second self-alignment mark pattern group 300 toward the fourth self-alignment mark pattern group 500, and “right” refers to the direction of the fourth self-alignment mark pattern group 500 toward the second self-alignment mark pattern group 300.

[0049] like Figure 6 and Figure 7 As shown, each of the self-alignment mark graphic groups includes a first self-alignment mark graphic 210 and a second self-alignment mark graphic 220, and the first self-alignment mark graphic 210 and the second self-alignment mark graphic 220 are arranged at intervals.

[0050] The first self-alignment mark graphic 210 includes a first graphic and a second graphic, and the second self-alignment mark graphic 220 includes a first graphic. In the first self-alignment mark graphic 210, the second graphic is located inside the first graphic.

[0051] The first graphic is formed by two identical first rectangular bars 211 and 212 enclosing an L shape, and the two first rectangular bars 211 and 212 are arranged at intervals; the second graphic is formed by four identical second rectangular bars 213, 214, 215, and 216 enclosing a rectangular ring shape, and there is a gap between adjacent second rectangular bars. Among them, the length of the first rectangular bar is greater than the length of the second rectangular bar.

[0052] Please continue to refer to Figure 5-Figure 7 , in the first self-alignment mark graphic group 200, the first self-alignment mark graphic 210 is arranged at intervals on the left side of the second self-alignment mark graphic 220, and the first graphic of the first self-alignment mark graphic 210 covers the second graphic from the left side and the upper side of the second graphic. The first graphic of the second self-alignment mark graphic 220 is generally in the shape of a "factory" character, which includes the left side and the upper side of a rectangle. In the second self-alignment mark graphic group 300, the first self-alignment mark graphic 210 is arranged at intervals above the second self-alignment mark graphic 220, the first graphic of the first self-alignment mark graphic 210 covers the second graphic from the upper side and the right side of the second graphic, and the first graphic of the second self-alignment mark graphic 220 includes the upper side and the right side of a rectangle. In the third self-alignment mark graphic group 400, the first self-alignment mark graphic 210 is arranged at intervals on the right side of the second self-alignment mark graphic 220, the first graphic of the first self-alignment mark graphic 210 covers the second graphic from the right side and the lower side of the second graphic, and the first graphic of the second self-alignment mark graphic 220 includes the lower side and the right side of a rectangle. In the fourth self-alignment mark graphic group 500, the first self-alignment mark graphic 210 is arranged at intervals below the second self-alignment mark graphic 220, the first graphic of the first self-alignment mark graphic 210 covers the second graphic from the left side and the lower side of the second graphic, and the first graphic of the second self-alignment mark graphic 220 includes the left side and the lower side of a rectangle.

[0053] That is to say, the first self-alignment mark pattern 210 of the first self-alignment mark pattern group 200 is arranged opposite to the second self-alignment mark pattern 220 of the third self-alignment mark pattern group 400, and the second self-alignment mark pattern 220 of the first self-alignment mark pattern group 200 is arranged opposite to the first self-alignment mark pattern 210 of the third self-alignment mark pattern group 400; the first self-alignment mark pattern 210 of the second self-alignment mark pattern group 300 is arranged opposite to the second self-alignment mark pattern 220 of the fourth self-alignment mark pattern group 500, and the second self-alignment mark pattern 220 of the second self-alignment mark pattern group 300 is arranged opposite to the first self-alignment mark pattern 210 of the fourth self-alignment mark pattern group 500.

[0054] When the mask is used to form exposure units and overlay alignment marks on a wafer, the main pattern of the first area 100 of the mask forms an exposure unit on the wafer, the first self-alignment mark pattern group 200 forms a first self-alignment mark group on the upper side of the exposure unit, the second self-alignment mark pattern group 300 forms a second self-alignment mark group on the right side of the exposure unit, the third self-alignment mark pattern group 400 forms a third self-alignment mark group on the lower side of the exposure unit, and the fourth self-alignment mark pattern group 500 forms a fourth self-alignment mark group on the left side of the exposure unit. The first self-alignment mark pattern in each self-alignment mark pattern forms a first self-alignment mark 210' on the wafer, and the second self-alignment mark pattern forms a second self-alignment mark 220' on the wafer. Of course, the exposure unit at the edge position of the wafer may form self-alignment marks on two or three sides in four directions.

[0055] Take the exposure between two adjacent exposure units (such as the left exposure unit and the right exposure unit) in the left-right direction as an example. Figure 8 As shown, the first self-alignment mark 210' of the second self-alignment mark group of the left exposure unit and the second self-alignment mark 220' of the fourth self-alignment mark group of the right exposure unit form a "U"-shaped overlay alignment mark; at the same time, the second self-alignment mark 220' of the second self-alignment mark group of the left exposure unit and the first self-alignment mark 210' of the fourth self-alignment mark group of the right exposure unit form a "U"-shaped overlay alignment mark.

[0056] Taking the exposure between two adjacent exposure units (for example, an upper exposure unit and a lower exposure unit) in the upper and lower directions as an example, the second self-alignment mark 220' of the third self-alignment mark group of the upper exposure unit and the first self-alignment mark 210' of the first self-alignment mark group of the lower exposure unit form a "U"-shaped overlay alignment mark; at the same time, the first self-alignment mark 210' of the third self-alignment mark group of the upper exposure unit and the second self-alignment mark 220' of the first self-alignment mark group of the lower exposure unit form a "U"-shaped overlay alignment mark.

[0057] like Fig. 9 As shown, in the prior art, between two adjacent exposure units (for example, an upper exposure unit and a lower exposure unit) in the vertical direction, and when an inner frame alignment mark formed later and an outer frame alignment mark formed earlier are offset, the width of the rectangular strips constituting the outer frame and the width of the rectangular strips constituting the inner frame are both set to L1, the downward offset of the inner frame is L2, so that L2=L1, the upward offset of the outer frame is L3, and the measured offset is the distance L4 between the center point of the inner frame and the center point of the outer frame in the vertical direction. At this time, L4=2L1.

[0058] like Fig.10 As shown, in the overlay alignment mark between two adjacent exposure units in the upper and lower directions, when the second self-alignment mark 220' in the first self-alignment mark group of the front exposure unit and the first self-alignment mark 210' in the third self-alignment mark group of the rear exposure unit form a "U"-shaped overlay alignment mark and an offset occurs, the width of the rectangular strips constituting the first figure and the width of the rectangular strips constituting the second figure are both set to be L1, the downward offset of the second figure of the first self-alignment mark 210' in the rear exposure unit is L2, and the upward offset of the first figure of the second self-alignment mark 220' in the front exposure unit is L3. During detection, the system automatically captures the center point (i.e., the center point of the inner and outer frames) D1 of the overlay alignment mark and the center point D2 of the second figure of the first self-alignment mark 210' in the rear exposure unit, so that the measured offset of the overlay alignment mark is L5, at this time L5=L1, i.e., L5=1 / 2L4. That is to say, using the same overlay model, the measured offset of the overlay mark obtained by the mask of the present invention is the compensated offset. Therefore, the mask of the present invention can more accurately feedback the actual offset of the overlay mark, ensure the stability of the first layer of overlay alignment mark, and thus reduce the rework rate.

[0059] In summary, the utility model provides a mask plate and a semiconductor device prepared using the mask plate, the mask plate including a main graphic and four groups of self-alignment mark graphic groups, the mask plate having a first area and a second area, the second area is arranged in a ring on the outside of the first area, the first area is provided with the main graphic, all the self-alignment mark graphic groups are arranged in the second area, and are arranged at intervals around the main graphic, each of the self-alignment mark graphic groups includes: a first self-alignment mark graphic, the first self-alignment mark graphic includes a first graphic and a second graphic, the second graphic is located on the inner side of the first graphic; a second self-alignment mark graphic, the first self-alignment mark graphic and the second self-alignment mark graphic are arranged at intervals, and the second self-alignment mark graphic only includes the first graphic, which can achieve the unexpected technical effect of more accurately feeding back the actual offset of the overlay mark, ensuring the stability of the overlay alignment mark of the first layer, thereby reducing the rework rate.

[0060] In addition, it should be noted that, unless otherwise specified or indicated, the terms "first" and "second" in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0061] It is understandable that, although the utility model has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the utility model. For any technician familiar with the art, without departing from the scope of the technical solution of the utility model, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the utility model, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. A mask, comprising a main pattern and four groups of self-alignment mark pattern groups, the mask having a first area and a second area, the second area being arranged outside the first area, the first area being provided with the main pattern, all the self-alignment mark pattern groups being arranged in the second area and being arranged at intervals around the main pattern, characterized in that: Each of the self-alignment mark pattern groups comprises: a first self-alignment mark pattern, the first self-alignment mark pattern comprising a first pattern and a second pattern, the second pattern being located inside the first pattern; A second self-alignment mark pattern, wherein the first self-alignment mark pattern and the second self-alignment mark pattern are arranged alternately, and the second self-alignment mark pattern only includes the first pattern.

2. The mask according to claim 1, characterized in that: The first figure is formed into an L shape by two identical first rectangular strips, and the two first rectangular strips are arranged at intervals; The second figure is formed into a rectangular ring by four identical second rectangular strips, and there are gaps between adjacent second rectangular strips.

3. The mask according to claim 2, characterized in that: The length of the first rectangular strip is greater than the length of the second rectangular strip.

4. The mask according to claim 1, characterized in that: The four groups of self-alignment mark pattern groups are respectively: A first self-alignment mark pattern group, located on the upper side of the first area; A second self-alignment mark pattern group is located on the right side of the first region and is a pattern group obtained by rotating the first self-alignment mark pattern group 90° clockwise; A third self-alignment mark pattern group is located at the lower side of the first region, parallel to and directly opposite to the first self-alignment mark pattern group, and is a pattern group obtained by rotating the second self-alignment mark pattern group 90° clockwise; The fourth self-alignment mark pattern group is located on the left side of the first region, parallel to and opposite to the second self-alignment mark pattern group, and is a pattern group obtained by rotating the third self-alignment mark pattern group by 90° clockwise.

5. The mask according to claim 4, characterized in that: In the first self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the left side of the second self-alignment mark pattern, and the first pattern of the first self-alignment mark pattern covers the second pattern from the left side and the top side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the left side and the top side of the rectangular ring.

6. The mask according to claim 4, characterized in that: In the second self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the upper side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the upper side and the right side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the upper side and the right side of the rectangular ring.

7. The mask according to claim 4, characterized in that: In the third self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart on the right side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the right side and bottom side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the lower side and right side of a rectangular ring.

8. The mask according to claim 4, characterized in that: In the fourth self-alignment mark pattern group, the first self-alignment mark pattern is spaced apart at the lower side of the second self-alignment mark pattern, the first pattern of the first self-alignment mark pattern covers the second pattern from the left side and the bottom side of the second pattern, and the first pattern of the second self-alignment mark pattern includes the left side and the bottom side of the rectangular ring.

9. The mask according to claim 4, characterized in that: The first self-alignment mark pattern of the first self-alignment mark pattern group is arranged opposite to the second self-alignment mark pattern of the third self-alignment mark pattern group, and the second self-alignment mark pattern of the first self-alignment mark pattern group is arranged opposite to the first self-alignment mark pattern of the third self-alignment mark pattern group.

10. The mask according to claim 4, characterized in that: The first self-alignment mark pattern of the second self-alignment mark pattern group is disposed opposite to the second self-alignment mark pattern of the fourth self-alignment mark pattern group, and the second self-alignment mark pattern of the second self-alignment mark pattern group is disposed opposite to the first self-alignment mark pattern of the fourth self-alignment mark pattern group.

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