Test structures and semiconductor devices

Abstract

The application relates to a test structure and a semiconductor device. The test structure comprises: a test unit, comprising a first test unit and a second test unit, the first test unit and the second test unit each comprising a dense area and a sparse area, and the first test unit and the second test unit do not overlap in orthographic projection on the same plane; a contact hole test unit, comprising a first contact hole test unit and a second contact hole test unit, the first contact hole test unit and the second contact hole test unit each comprising a dense area and a sparse area, and the first contact hole test unit and the second contact hole test unit do not overlap in orthographic projection on the same plane; wherein the first test unit, the second test unit, the first contact hole test unit and the second contact hole test unit are located on different layers; and the test unit and the contact hole test unit overlap in orthographic projection on the same plane. The problem that the dense area and the sparse area in the test structure need to be separately prepared during sample preparation can be solved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a test structure and a semiconductor device. Background Technology

[0002] With the continuous development of semiconductor process technology, it is necessary to test and analyze various key structural layers during the semiconductor device manufacturing process to evaluate whether their morphology and dimensional data meet the process requirements.

[0003] Currently, when preparing test structures for rotating plates in structural analysis, the angle between the cleavage planes of the rotating plates and the conventional placement of the test structure, as well as the specific angles of different test patterns within the test structure, means that not all test patterns have angles that correspond to the cleavage planes. This makes it impossible to obtain the complete cross-sectional morphology of all patterns in one step using the conventional splitting method. Furthermore, dense and sparse areas of the same layer of test units, as well as test units in different layers, need to be prepared separately, which consumes a lot of manpower and resources. Summary of the Invention

[0004] Therefore, it is necessary to provide a test structure and semiconductor device to address the issues of dense and sparse areas of test units in the same layer and the need for separate sample preparation of test units in different layers in the aforementioned test structure.

[0005] To achieve the above objectives, this application provides a test structure, which includes:

[0006] The test unit includes a first test unit and a second test unit. Both the first test unit and the second test unit include dense areas and sparse areas. The orthographic projections of the first test unit and the second test unit on the same plane do not overlap.

[0007] The contact hole testing unit includes a first contact hole testing unit and a second contact hole testing unit. Both the first contact hole testing unit and the second contact hole testing unit include dense areas and sparse areas. The orthographic projections of the first contact hole testing unit and the second contact hole testing unit on the same plane do not overlap.

[0008] The first test unit, the second test unit, the first contact hole test unit, and the second contact hole test unit are all located on different layers; the test units and the contact hole test units overlap in orthographic projection on the same plane.

[0009] In one embodiment, the first test unit includes: a first test subunit, a second test subunit, and a third test subunit; the first test subunit includes:

[0010] The first test strip includes the opposing first and second ends;

[0011] Multiple second test strips are arranged in parallel at intervals on opposite sides of the first test strip, extending from the first end of the first test strip to the second end of the first test strip;

[0012] Multiple third test strips are arranged in parallel at intervals on opposite sides of the first test strip, extending from the second end of the first test strip to the first end of the first test strip, and there is a gap between the third test strips and the second test strip;

[0013] The second test subunit includes:

[0014] The fourth test strip is parallel to, perpendicular to, or at a 45° angle to the first test strip, and has a gap between it and the first test strip;

[0015] Multiple fifth test strips are arranged in parallel at intervals on opposite sides of the fourth test strip, and the length of the fifth test strip is less than the length of the fourth test strip;

[0016] The third test subunit includes:

[0017] The sixth test strip includes a first end and a second end opposite to each other, which are perpendicular to or at a 45° angle to the first test strip, and perpendicular to or at a 45° angle to the fourth test strip;

[0018] Multiple seventh test strips are arranged in parallel at intervals on opposite sides of the sixth test strip, extending from the first end of the sixth test strip to the second end of the sixth test strip.

[0019] In one embodiment, the second test unit includes: a fourth test subunit, a fifth test subunit, and a sixth test subunit; the fourth test subunit includes:

[0020] The eighth test strip includes the first and second ends, which are opposite each other;

[0021] Multiple ninth test strips are arranged in parallel at intervals on opposite sides of the eighth test strip, extending from the first end of the eighth test strip to the second end of the eighth test strip;

[0022] Multiple tenth test strips are arranged in parallel at intervals on opposite sides of the eighth test strip, extending from the second end of the eighth test strip to the first end of the eighth test strip, and there is a gap between the tenth test strip and the ninth test strip;

[0023] The fifth test subunit includes:

[0024] The eleventh test strip is parallel to, perpendicular to, or at a 45° angle to the eighth test strip, and is spaced apart from the eighth test strip;

[0025] Multiple twelfth test strips are arranged in parallel at intervals on opposite sides of the eleventh test strip, and the length of the twelfth test strip is less than the length of the eleventh test strip;

[0026] The sixth test subunit includes:

[0027] The thirteenth test strip includes a first end and a second end that are opposite each other, perpendicular to or at a 45° angle to the eighth test strip, and perpendicular to or at a 45° angle to the eleventh test strip;

[0028] Multiple fourteenth test strips are arranged in parallel at intervals on opposite sides of the thirteenth test strip, extending from the first end of the thirteenth test strip to the second end of the thirteenth test strip.

[0029] In one embodiment, the spacing between adjacent second test strips, the spacing between adjacent third test strips, the spacing between the second test strip and the first test strip, the spacing between the third test strip and the first test strip, the spacing between adjacent fifth test strips, the spacing between the fifth test strip and the fourth test strip, the spacing between adjacent seventh test strips, the spacing between the seventh test strip and the sixth test strip, the spacing between adjacent ninth test strips, the spacing between adjacent tenth test strips, the spacing between the ninth test strip and the eighth test strip, the spacing between adjacent twelfth test strips, the spacing between the twelfth test strip and the eleventh test strip, the spacing between adjacent fourteenth test strips, and the spacing between the fourteenth test strip and the thirteenth test strip all satisfy the minimum design rule.

[0030] In one embodiment, both the dense region and the sparse region of the first contact hole test unit are provided with a plurality of first contact holes. The spacing between adjacent first contact holes in the dense region of the first contact hole test unit is smaller than the spacing between adjacent first contact holes in the sparse region of the first contact hole test unit, and smaller than the spacing between the dense region and the sparse region of the first contact hole test unit.

[0031] In one embodiment, a plurality of second contact holes are provided in both the dense region and the sparse region of the second contact hole test unit. The spacing between adjacent second contact holes in the dense region of the second contact hole test unit is smaller than the spacing between adjacent second contact holes in the sparse region of the second contact hole test unit, and smaller than the spacing between the dense region and the sparse region of the second contact hole test unit.

[0032] In one embodiment, the spacing between adjacent first contact holes in the dense area of ​​the first contact hole test unit and the spacing between adjacent second contact holes in the dense area of ​​the second contact hole test unit both satisfy the minimum design rule.

[0033] In one embodiment, the test structure includes a plurality of first test units, a plurality of second test units, a plurality of first contact hole test units, and a plurality of second contact hole test units.

[0034] In one embodiment, a plurality of first test units, a plurality of second test units, a plurality of first contact hole test units, and a plurality of second contact hole test units are located in different layers.

[0035] This application also provides a semiconductor device including the test structure described in any of the above embodiments.

[0036] The test structure of this application includes a test unit and a contact hole test unit. The test unit includes a first test unit and a second test unit, whose orthographic projections on the same plane do not overlap. The contact hole test unit includes a first contact hole test unit and a second contact hole test unit, whose orthographic projections on the same plane do not overlap. Both the first and second test units include dense and sparse regions. This solves the problem of separating the preparation of samples for dense and sparse regions in the test structure, enabling simultaneous preparation of samples for both dense and sparse regions. The first test unit, the second test unit, the first contact hole test unit, and the second contact hole test unit are all located on different layers, and the orthographic projections of the test units and the contact hole test units on the same plane overlap. This allows for simultaneous preparation of samples from different layers of the test structure, and analytical samples from all structural layers can be obtained simultaneously in a single sectioning operation, saving manpower and resources and improving R&D efficiency.

[0037] The semiconductor device of this application includes a test structure, which has the same beneficial effects as the test structure. When preparing samples of this semiconductor device, it is possible to prepare samples of dense and sparse regions at the same time, and it is also possible to prepare samples of different layers of test structures at the same time. One dicing can obtain analytical samples of all structural layers of the semiconductor device at the same time, saving manpower and resources and improving R&D efficiency. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the test structure provided in one embodiment, where direction A represents the cleavage direction;

[0040] Figure 2 This is a schematic diagram of the structure of the first test unit in a test structure provided in one embodiment;

[0041] Figure 3 This is a schematic diagram of the structure of the first test subunit in a test structure provided in one embodiment;

[0042] Figure 4 This is a schematic diagram of the structure of the second test subunit in a test structure provided in one embodiment;

[0043] Figure 5 This is a schematic diagram of the structure of the third test subunit in a test structure provided in one embodiment;

[0044] Figure 6 This is a schematic diagram of the structure of the second test unit in a test structure provided in one embodiment;

[0045] Figure 7 This is a schematic diagram of the structure of the fourth test subunit in a test structure provided in one embodiment;

[0046] Figure 8 This is a schematic diagram of the structure of the fifth test subunit in a test structure provided in one embodiment;

[0047] Figure 9 This is a schematic diagram of the sixth test subunit in a test structure provided in one embodiment;

[0048] Figure 10 This is a schematic diagram of the structure of the first contact hole test unit in a test structure provided in one embodiment;

[0049] Figure 11This is a schematic diagram of the structure of the second contact hole test unit in a test structure provided in one embodiment.

[0050] Explanation of reference numerals in the attached figures:

[0051] 100. Test Unit; 200. Contact Hole Test Unit; 1. First Test Unit; 101. Dense Area of ​​the First Test Unit; 102. Sparse Area of ​​the First Test Unit; 11. First Test Subunit; 111. First Test Strip; 112. Second Test Strip; 113. Third Test Strip; 12. Second Test Subunit; 121. Fourth Test Strip; 122. Fifth Test Strip; 13. Third Test Subunit; 131. Sixth Test Strip; 132. Seventh Test Strip; 2. Second Test Unit; 201. Dense Area of ​​the Second Contact Test Unit; 202. Sparse Area of ​​the Second Test Unit; 21. Fourth Test Subunit 211, Eighth Test Strip; 212, Ninth Test Strip; 213, Tenth Test Strip; 22, Fifth Test Subunit; 221, Eleventh Test Strip; 222, Twelfth Test Strip; 23, Sixth Test Subunit; 231, Thirteenth Test Strip; 232, Fourteenth Test Strip; 3, First Contact Hole Test Unit; 301, Dense Area of ​​First Contact Hole Test Unit; 302, Sparse Area of ​​First Contact Hole Test Unit; 31, First Contact Hole; 4, Second Contact Hole Test Unit; 401, Dense Area of ​​Second Contact Hole Test Unit; 402, Sparse Area of ​​Second Contact Hole Test Unit; 41, Second Contact Hole. Detailed Implementation

[0052] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0054] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this application, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0055] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0056] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0057] With the continuous development of semiconductor process technology, it is necessary to test and analyze various key structural layers during the semiconductor device manufacturing process to evaluate whether their morphology and dimensional data meet the process requirements.

[0058] Currently, when preparing test structures for rotating plates in structural analysis, the angle between the cleavage planes of the rotating plates and the conventional placement of the test structure, as well as the specific angles of different test patterns within the test structure, means that not all test patterns have angles that correspond to the cleavage planes. This makes it impossible to obtain the complete cross-sectional morphology of all patterns in one step using the conventional splitting method. Furthermore, dense and sparse areas of the same layer of test units, as well as test units in different layers, need to be prepared separately, which consumes a lot of manpower and resources.

[0059] Therefore, it is necessary to provide a test structure that addresses the issues of dense and sparse areas of the same layer of test units and the need for separate sample preparation for test units of different layers in the aforementioned test structure.

[0060] To achieve the above objectives, this application provides a test structure, such as... Figure 1 As shown, the test structure includes: a test unit 100 and a contact hole test unit 200; the test unit 100 includes a first test unit 1 and a second test unit 2, both of which include dense and sparse regions, and their orthographic projections on the same plane do not overlap; the contact hole test unit 200 includes a first contact hole test unit 3 and a second contact hole test unit 4, both of which include dense and sparse regions, and their orthographic projections on the same plane do not overlap; wherein, the first test unit 1, the second test unit 2, the first contact hole test unit 3, and the second contact hole test unit 4 are all located on different layers; the orthographic projections of the test unit 100 and the contact hole test unit 200 on the same plane overlap.

[0061] Specifically, see Figure 1 The first test unit 1 includes a dense region 101 and a sparse region 102, the second test unit 2 includes a dense region 201 and a sparse region 202, the first contact hole test unit 3 includes a dense region 301 and a sparse region 302, and the second contact hole test unit 4 includes a dense region 401 and a sparse region 402.

[0062] It should be noted that, since the first test unit 1, the second test unit 2, the first contact hole test unit 3, and the second contact hole test unit 4 are all located on different layers, Figure 1The test structure shown is an orthographic projection of the first test unit 1 and the second test unit 2 on the same plane, and an orthographic projection of the first contact hole test unit 3 and the second contact hole test unit 4 on the same plane; the same plane refers to the same projection reference plane. Specifically, the lower surface of the base of the test structure can be used as the projection reference plane. The lower surface of the base of the test structure is the bottommost lower surface of the entire test structure.

[0063] In this design, the projection reference planes of the first test unit 1 and the second test unit 2 are the same as the projection reference planes of the first contact hole test unit 3 and the second contact hole test unit 4. However, because the orthographic projections of the first test unit 1 and the second test unit 2 on the projection reference plane intersect and do not overlap, and the orthographic projections of the first contact hole test unit 3 and the second contact hole test unit 4 on the projection reference plane intersect and do not overlap, in order to more clearly view and confirm the test structure diagrams, the orthographic projection diagrams of the first test unit 1 and the second test unit 2 on the same projection reference plane are placed together, and the orthographic projection diagrams of the first contact hole test unit 3 and the second contact hole test unit 4 on the same projection reference plane are placed together. The resulting structural schematic diagram is as follows. Figure 1 As shown in the test unit 100 and contact hole test unit 200, when along Figure 1 When the test structure is cleaved along cleavage direction A as shown, samples of the dense and sparse regions of the first test unit 1, the second test unit 2, the first contact hole test unit 3, and the second contact hole test unit 4 can be obtained simultaneously. Furthermore, each of the first test unit 1, the second test unit 2, the first contact hole test unit 3, and the second contact hole test unit 4 contains multiple dense and multiple sparse regions. Figure 1 Only some dense and some sparse areas of each unit are marked.

[0064] Further, please refer to Figure 1The non-overlapping orthographic projections of the first test unit 1 and the second test unit 2 on the same plane mean that there is a gap between their orthographic projections on the projection reference plane. The non-overlapping orthographic projections of the first contact hole test unit 3 and the second contact hole test unit 4 on the same plane mean that there is a gap between their orthographic projections on the projection reference plane. The overlapping orthographic projections of test unit 100 and contact hole test unit 200 on the same plane can include: partial or complete overlap between the orthographic projections of the first contact hole test unit 3 and the first test unit 1 on the projection reference plane, and / or partial or complete overlap between the orthographic projections of the second contact hole test unit 4 and the first test unit 1 on the projection reference plane, and / or partial or complete overlap between the orthographic projections of the first contact hole test unit 3 and the second test unit 2 on the projection reference plane, and / or partial or complete overlap between the orthographic projections of the second contact hole test unit 4 and the second test unit 2 on the projection reference plane.

[0065] The test structure in the above embodiment includes a test unit 100 and a contact hole test unit 200. The test unit 100 includes a first test unit 1 and a second test unit 2, whose orthographic projections on the same plane do not overlap. The contact hole test unit 200 includes a first contact hole test unit 3 and a second contact hole test unit 4, whose orthographic projections on the same plane do not overlap. Both the first test unit 2 and the second test unit 3 include dense and sparse regions. The first contact hole test unit 3 and the second contact hole test unit 4... Each of the hole testing units 4 includes both dense and sparse regions, which can solve the problem of separating the dense and sparse regions during sample preparation in the test structure, and achieve simultaneous sample preparation of the dense and sparse regions. The first test unit 1, the second test unit 2, the first contact hole test unit 3, and the second contact hole test unit 4 are all located in different layers, and the test unit 100 and the contact hole test unit 200 overlap in the orthographic projection on the same plane, which can realize the simultaneous sample preparation of different layers of the test structure. A single dicing can obtain analytical samples of all structural layers at the same time, saving manpower and resources and improving R&D efficiency.

[0066] In some embodiments, the first test unit 1 may include any one of an active region test unit and a polysilicon test unit. The second test unit 2 may include any one of a first metal layer test unit and a second metal layer test unit. The first contact hole test unit 3 may include any one of an interlayer contact hole test unit and a first layer metal hole test unit. The second contact hole test unit 4 may include any one of a second layer metal hole test unit and a top layer metal hole test unit.

[0067] In one embodiment, see Figures 1 to 9The first test unit 1 includes: a first test subunit 11, a second test subunit 12 and a third test subunit 13; the second test unit 2 includes: a fourth test subunit 21, a fifth test subunit 22 and a sixth test subunit 23.

[0068] Among them, the first test subunit 11 and the fifth test subunit 22 are combined in pairs; the second test subunit 12 and the fourth test subunit 21 are combined in pairs; each of the third test subunits 13 is combined in pairs and arranged at two adjacent corners of the test structure; each of the sixth test subunits 23 is combined in pairs and arranged at the other two corners of the test structure; the first contact hole test unit 3 and the second contact hole test unit 4 are arranged parallel, perpendicular, or at a 45° angle to each other.

[0069] In some examples, see Figure 1 The first test subunit 11 and the fifth test subunit 22 are paired up. In each pair, the projection of the first test subunit 11 onto the projection reference plane is parallel and adjacent to the projection of the fifth test subunit 22 onto the projection reference plane. In different pairs, the projection of the first test subunit 11 onto the projection reference plane is perpendicular, parallel, or at a 45° angle to the projection of the fifth test subunit 22 onto the projection reference plane. The second test subunit 12 and the fourth test subunit 21 are paired up. In each pair, the projection of the second test subunit 12 onto the projection reference plane is parallel and adjacent to the projection of the fourth test subunit 21 onto the projection reference plane. In different pairs, the projection of the second test subunit 12 onto the projection reference plane is perpendicular, parallel, or at a 45° angle to the projection of the fourth test subunit 21 onto the projection reference plane. The pairing of each third test subunit 13 refers to the pairing of two third test subunits 13 located in opposite directions and parallel to each other. The pairing of each sixth test subunit 23 refers to the pairing of two sixth test subunits 23 located in opposite directions and parallel to each other.

[0070] In some examples, see Figure 1 and 2 The projections of the first test subunit 11, the second test subunit 12, the third test subunit 13, the fourth test subunit 21, the fifth test subunit 22, and the sixth test subunit 23 onto the projection reference plane do not overlap.

[0071] In one embodiment, see Figure 1 and Figure 2The first test subunit 11 includes: a first test strip 111, a plurality of second test strips 112, and a plurality of third test strips 113; the first test strip 111 includes a first end and a second end opposite to each other; the plurality of second test strips 112 are arranged in parallel at intervals on opposite sides of the first test strip 111, extending from the first end of the first test strip 111 to the second end of the first test strip 111; the plurality of third test strips 113 are arranged in parallel at intervals on opposite sides of the first test strip 111, extending from the second end of the first test strip 111 to the first end of the first test strip 111, and there is a gap between the third test strips 113 and the second test strips 112; the second test subunit 12 includes: a fourth test strip 121 and a plurality of fifth test strips 122; the fourth test strip 121... Test strip 21 is parallel to, perpendicular to, or at a 45° angle to the first test strip 111, and has a gap between it and the first test strip 111; multiple fifth test strips 122 are arranged in parallel at intervals on opposite sides of the fourth test strip 121, and the length of the fifth test strip 122 is less than the length of the fourth test strip 121; the third test subunit 13 includes: a sixth test strip 131 and multiple seventh test strips 132; the sixth test strip 131 includes a first end and a second end opposite to each other, is perpendicular to or at a 45° angle to the first test strip 111, and is perpendicular to or at a 45° angle to the fourth test strip 121; multiple seventh test strips 132 are arranged in parallel at intervals on opposite sides of the sixth test strip 131, extending from the first end of the sixth test strip 131 to the second end of the sixth test strip 131.

[0072] In some embodiments, see Figure 2 The number of first test subunits 11 is the same as the number of second test subunits 12; the number of third test subunits 13 is greater than the number of first test subunits 11; the number of third test subunits 13 is greater than the number of second test subunits 12.

[0073] In some embodiments, see Figure 3 Let 'a' be the length of the first test strip 111, 'b' be the length of the second test strip 112, and 'c' be the length of the third test strip 113. The length 'a' of the first test strip 111 can be 30–34 μm; specifically, 'a' can be 30 μm, 31 μm, 32 μm, 33 μm, or 34 μm, or any other length between 30 and 34 μm. The length 'b' of the second test strip 112 can be 6–10 μm; specifically, 'b' can be 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or any other length between 6 and 10 μm. The length 'c' of the third test strip 113 can be 6–10 μm; specifically, 'c' can be 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or any other length between 6 and 10 μm.

[0074] In some examples, the length b of the second test strip 112 can be the same as the length c of the third test strip 113; the length b of the second test strip 112 can be one-quarter of the length a of the first test strip 111; and the length c of the third test strip 113 can be one-quarter of the length a of the first test strip 111.

[0075] In some embodiments, see Figure 4 d represents the length of the fourth test strip 121, and e represents the length of the fifth test strip 122. The length d of the fourth test strip 121 can be 30–34 μm; specifically, the length d of the fourth test strip 121 can be 30 μm, 31 μm, 32 μm, 33 μm, or 34 μm, or any other length between 30 and 34 μm. The length e of the fifth test strip 122 can be 14–18 μm; specifically, the length e of the fifth test strip 122 can be 14 μm, 15 μm, 16 μm, 17 μm, or 18 μm, or any other length between 14 and 18 μm.

[0076] In some examples, the length d of the fourth test strip 121 can be the same as the length a of the first test strip 111; the length e of the fifth test strip 122 can be half the length d of the fourth test strip 121.

[0077] In some examples, see Figure 5 Where f is the length of the sixth test strip 131 and g is the length of the seventh test strip 132; wherein, the length f of the sixth test strip 131 can be 14 to 18 μm; specifically, the length f of the sixth test strip 131 can be 14 μm, 15 μm, 16 μm, 17 μm or 18 μm, or any other length between 14 and 18 μm. The length g of the seventh test strip 132 can be 6 to 10 μm; specifically, the length g of the seventh test strip 132 can be 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, or any other length between 6 and 10 μm. In each of the two third test sub-units 13 within a group, the distance h between the sixth test strip 131 of one third test sub-unit 13 and the closest seventh test strip 132 in the other third test sub-unit 13 can be 3 to 6 μm. Specifically, the distance h can be 3 μm, 4 μm, 5 μm or 6 μm, or other distances between 3 and 6 μm, without being limited by the specific distances listed.

[0078] In some examples, the length f of the sixth test strip 131 can be half the length a of the first test strip 111; the length f of the sixth test strip 131 can be half the length d of the fourth test strip 121; the length f of the sixth test strip 131 can be the same as the length e of the fifth test strip 122; and the length g of the seventh test strip 132 can be half the length f of the sixth test strip 131.

[0079] In one embodiment, see Figure 1 and Figure 6 The fourth test subunit 21 includes: an eighth test strip 211, a plurality of ninth test strips 212, and a plurality of tenth test strips 213; the eighth test strip 211 includes a first end and a second end opposite to each other; the plurality of ninth test strips 212 are arranged in parallel on opposite sides of the eighth test strip 211, extending from the first end of the eighth test strip 211 to the second end of the eighth test strip 211; the plurality of tenth test strips 213 are arranged in parallel on opposite sides of the eighth test strip 211, extending from the second end of the eighth test strip 211 to the first end of the eighth test strip 211, and there is a gap between the tenth test strips 213 and the ninth test strips 212; the fifth test subunit 22 includes: an eleventh test strip 221, and a plurality of twelfth test strips 222; the eleventh test strip 221 and the eighth test strip 212 are arranged in parallel on opposite sides of the eighth test strip 211, extending from the second end of the eighth test strip 211 to the first end of the eighth test strip 211, and there is a gap between the tenth test strips 213 and the ninth test strips 212; Test strips 211 are parallel, perpendicular, or at a 45° angle to each other, and are spaced apart from the eighth test strip 211; multiple twelfth test strips 222 are arranged in parallel at intervals on opposite sides of the eleventh test strip 221, and the length of the twelfth test strip 222 is less than the length of the eleventh test strip 221; the sixth test subunit 23 includes: a thirteenth test strip 231 and multiple fourteenth test strips 232; the thirteenth test strip 231 includes a first end and a second end opposite to each other, perpendicular or at a 45° angle to the eighth test strip 211, and perpendicular or at a 45° angle to the eleventh test strip 221; multiple fourteenth test strips 232 are arranged in parallel at intervals on opposite sides of the thirteenth test strip 231, extending from the first end of the thirteenth test strip 231 to the second end of the thirteenth test strip 231.

[0080] In some embodiments, see Figure 6 The number of fourth test subunits 21 is the same as the number of fifth test subunits 22; the number of sixth test subunits 23 is greater than the number of fourth test subunits 21; the number of sixth test subunits 23 is greater than the number of fifth test subunits 22.

[0081] In some embodiments, see Figure 7Let j be the length of the eighth test strip 211, k be the length of the ninth test strip 212, and m be the length of the tenth test strip 213. The length j of the eighth test strip 211 can be 30–34 μm; specifically, the length j of the eighth test strip 211 can be 30 μm, 31 μm, 32 μm, 33 μm, or 34 μm, or any other length between 30 and 34 μm. The length k of the ninth test strip 212 can be 6–10 μm; specifically, the length k of the ninth test strip 212 can be 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or any other length between 6 and 10 μm. The length m of the tenth test strip 213 can be 6–10 μm; specifically, the length m of the tenth test strip 213 can be 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or any other length between 6 and 10 μm.

[0082] Furthermore, the length k of the ninth test strip 212 can be the same as the length m of the tenth test strip 213; the length k of the ninth test strip 212 can be one-quarter of the length j of the eighth test strip 211; and the length m of the tenth test strip 213 can be one-quarter of the length j of the eighth test strip 211.

[0083] In some embodiments, see Figure 8 Where n is the length of the eleventh test strip 221 and p is the length of the twelfth test strip 222; wherein, the length n of the eleventh test strip 221 can be 30 to 34 μm; specifically, the length n of the eleventh test strip 221 can be 30 μm, 31 μm, 32 μm, 33 μm or 34 μm, or any other length between 30 and 34 μm. The length p of the twelfth test strip 222 can be 14 to 18 μm; specifically, the length p of the twelfth test strip 222 can be 14 μm, 15 μm, 16 μm, 17 μm or 18 μm, or any other length between 14 and 18 μm.

[0084] Furthermore, the length n of the eleventh test strip 221 can be the same as the length j of the eighth test strip 211; the length p of the twelfth test strip 222 can be half the length n of the eleventh test strip 221.

[0085] In some examples, see Figure 9q represents the length of the thirteenth test strip 231, and r represents the length of the fourteenth test strip 232. The length q of the thirteenth test strip 231 can be 14–18 μm; specifically, the length q of the thirteenth test strip 231 can be 14 μm, 15 μm, 16 μm, 17 μm, or 18 μm, or any other length between 14 and 18 μm. The length r of the fourteenth test strip 232 can be 6–10 μm; specifically, the length r of the fourteenth test strip 232 can be 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, or any other length between 6 and 10 μm. In each of the two third test sub-units 13, the distance s between the thirteenth test strip 231 of one third test sub-unit 13 and the nearest fourteenth test strip 232 in the other third test sub-unit 13 can be 3 to 6 μm. Specifically, the distance s can be 3 μm, 4 μm, 5 μm or 6 μm, or other distances between 3 and 6 μm, without being limited by the specific distances listed.

[0086] Furthermore, the length q of the thirteenth test strip 231 can be half the length j of the eighth test strip 211; the length q of the thirteenth test strip 231 can be half the length n of the eleventh test strip 221; the length q of the thirteenth test strip 231 can be the same as the length p of the twelfth test strip 222; and the length r of the fourteenth test strip 232 can be half the length q of the thirteenth test strip 231.

[0087] Specifically, the sample needs to be ground during the sample preparation process. When the sample size is very small, grinding is easy to over-grind when preparing cross-sectional samples, which makes it impossible to obtain accurate morphological information of the test structure. In the currently used test structure, the longest test strip in the test unit is only 8 μm. However, in this application, the lengths of the first test strip 111 (a), the fourth test strip 121 (d), the eighth test strip 211 (j), and the eleventh test strip 221 (n) are all between 30 and 34 μm, which are suitable for preparing samples by grinding. Moreover, grinding will not damage the morphology of the test structure, thus improving the sample preparation success rate and efficiency.

[0088] In one embodiment, see Figures 1 to 9The spacing between adjacent second test strips 112, adjacent third test strips 113, the spacing between second test strip 112 and first test strip 111, the spacing between third test strip 113 and first test strip 111, the spacing between adjacent fifth test strips 122, the spacing between fifth test strip 122 and fourth test strip 121, the spacing between adjacent seventh test strips 132, the spacing between seventh test strip 132 and sixth test strip 131, the spacing between adjacent ninth test strips 212, the spacing between adjacent tenth test strips 213, the spacing between ninth test strip 212 and eighth test strip 211, the spacing between tenth test strip 213 and eighth test strip 211, the spacing between adjacent twelfth test strips 222, the spacing between twelfth test strip 222 and eleventh test strip 221, the spacing between adjacent fourteenth test strips 232, and the spacing between fourteenth test strip 232 and thirteenth test strip 231 all meet the minimum design rule.

[0089] Here, the minimum design rule refers to setting the spacing between the structural graphics of the test units according to the minimum spacing, while meeting the design requirements of the test structure.

[0090] Specifically, the spacing between adjacent second test strips 112, the spacing between adjacent third test strips 113, the spacing between second test strip 112 and first test strip 111, the spacing between third test strip 113 and first test strip 111, the spacing between adjacent fifth test strips 122, the spacing between fifth test strip 122 and fourth test strip 121, the spacing between adjacent seventh test strips 132, the spacing between seventh test strip 132 and sixth test strip 131, the spacing between adjacent ninth test strips 212, the spacing between adjacent tenth test strips 213, the spacing between ninth test strip 212 and eighth test strip 211, the spacing between adjacent twelfth test strips 222, the spacing between twelfth test strip 222 and eleventh test strip 221, the spacing between adjacent fourteenth test strips 232, and the spacing between fourteenth test strip 232 and thirteenth test strip 231 all satisfy the minimum design rule. This refers to the spacing between adjacent second test strips 112, adjacent third test strips 113, the spacing between second test strip 112 and first test strip 111, the spacing between third test strip 113 and first test strip 111, the spacing between adjacent fifth test strips 122, the spacing between fifth test strip 122 and fourth test strip 121, the spacing between adjacent seventh test strips 132, the spacing between seventh test strip 132 and sixth test strip 131, the spacing between adjacent ninth test strips 212, the spacing between adjacent tenth test strips 213, the spacing between ninth test strip 212 and eighth test strip 211, the spacing between tenth test strip 213 and eighth test strip 211, the spacing between adjacent twelfth test strips 222, the spacing between twelfth test strip 222 and eleventh test strip 221, the spacing between adjacent fourteenth test strips 232, and the spacing between fourteenth test strip 232 and thirteenth test strip 231, all of which are set according to the minimum spacing.

[0091] In the above embodiments, the spacing between adjacent second test strips 112, the spacing between adjacent third test strips 113, the spacing between the second test strip 112 and the first test strip 111, the spacing between the third test strip 113 and the first test strip 111, the spacing between adjacent fifth test strips 122, the spacing between the fifth test strip 122 and the fourth test strip 121, the spacing between adjacent seventh test strips 132, the spacing between the seventh test strip 132 and the sixth test strip 131, the spacing between adjacent ninth test strips 212, the spacing between adjacent tenth test strips 213, the spacing between the ninth test strip 212 and the eighth test strip 211, the spacing between the tenth test strip 213 and the eighth test strip 211, and the spacing between adjacent twelfth test strips 112 and 113 are all specified. The spacing between strips 222, the spacing between the twelfth test strip 222 and the eleventh test strip 221, the spacing between adjacent fourteenth test strips 232, and the spacing between the fourteenth test strip 232 and the thirteenth test strip 231 all satisfy the minimum design rule, so that when the first test unit 1 is cleaved from the same cleavage plane, the analytical samples of the sparse and dense regions of the first test unit 1 can be obtained in one step, while minimizing the area occupied by the sparse and dense regions of the first test unit 1; and so that when the second test unit 2 is cleaved from the same cleavage plane, the analytical samples of the sparse and dense regions of the second test unit 2 can be obtained in one step, while minimizing the area occupied by the sparse and dense regions of the second test unit 2. In one embodiment, such as Figure 10 As shown, t is the spacing between adjacent first contact holes 31 in the dense area 301 of the first contact hole test unit, u is the spacing between adjacent first contact holes 31 in the sparse area 302 of the first contact hole test unit, and v is the spacing between the dense area 301 and the sparse area 302 of the first contact hole test unit; wherein, both the dense area 301 and the sparse area 302 of the first contact hole test unit are provided with multiple first contact holes 31, the spacing t between adjacent first contact holes 31 in the dense area 301 of the first contact hole test unit is smaller than the spacing u between adjacent first contact holes 31 in the sparse area 302 of the first contact hole test unit, and smaller than the spacing v between the dense area 301 and the sparse area 302 of the first contact hole test unit.

[0092] In the above embodiment, the distance t between adjacent first contact holes 31 in the dense region 301 of the first contact hole test unit is less than the distance u between adjacent first contact holes 31 in the sparse region 302 of the first contact hole test unit, and less than the distance v between the dense region 301 and the sparse region 302 of the first contact hole test unit. This allows for the simultaneous acquisition of analytical samples from the sparse and dense regions while minimizing the area occupied by the sparse and dense regions when the first contact hole test unit 3 is cleaved from the same cleavage plane.

[0093] In some embodiments, see still Figure 10 In the first contact hole test unit 3, there are multiple dense areas 301 and multiple sparse areas 302 of the first contact hole test unit. The dense areas 301 of the first contact hole test unit are perpendicular, parallel, or at a 45° angle to each other.

[0094] In one embodiment, such as Figure 11 As shown, x is the spacing between adjacent second contact holes 41 located in the dense area 401 of the second contact hole test unit, y is the spacing between adjacent second contact holes 41 located in the sparse area 402 of the second contact hole test unit, and z is the spacing between the dense area 401 and the sparse area 402 of the second contact hole test unit; wherein, both the dense area 401 and the sparse area 402 of the second contact hole test unit are provided with multiple second contact holes 41, the spacing x between adjacent second contact holes 41 located in the dense area 401 of the second contact hole test unit is smaller than the spacing y between adjacent second contact holes 41 located in the sparse area 402 of the second contact hole test unit, and smaller than the spacing z between the dense area 401 and the sparse area 402 of the second contact hole test unit.

[0095] In the above embodiment, the distance x between adjacent second contact holes 41 in the dense region 401 of the second contact hole test unit is smaller than the distance y between adjacent second contact holes 41 in the sparse region 402 of the second contact hole test unit, and smaller than the distance z between the dense region 401 and the sparse region 402 of the second contact hole test unit. This allows for the simultaneous acquisition of analytical samples from the sparse and dense regions while minimizing the area occupied by the sparse and dense regions when the second contact hole test unit 4 is cleaved from the same cleavage plane.

[0096] In some embodiments, see still Figure 11In the second contact hole test unit 4, there are multiple dense areas 401 and multiple sparse areas 402 of the second contact hole test unit. The dense areas 401 of the second contact hole test unit are perpendicular, parallel, or at a 45° angle to each other.

[0097] In one embodiment, participants Figures 10 to 11 The spacing between adjacent first contact holes 31 in the dense area 301 of the first contact hole test unit and the spacing between adjacent second contact holes 41 in the dense area 401 of the second contact hole test unit both meet the minimum design rules.

[0098] Here, the minimum design rule refers to setting the spacing between the contact holes of the contact hole test unit according to the minimum spacing, while meeting the design requirements of the test structure.

[0099] In the above embodiments, the spacing t between adjacent first contact holes 31 in the dense area 301 of the first contact hole test unit and the spacing x between adjacent second contact holes 41 in the dense area 401 of the second contact hole test unit both meet the minimum design rule, which can reduce the area occupied by the dicing channel and improve the flexibility of the structure placement. The dicing channel is the area used to dicing on the test structure during sample preparation.

[0100] In some embodiments, see still Figure 1 The dense area 301 of the first contact hole test unit is parallel to, perpendicular to, or at a 45° angle to the dense area 401 of the second contact hole test unit. Specifically, the fact that the dense area 301 of the first contact hole test unit is parallel to, perpendicular to, or at a 45° angle to the dense area 401 of the second contact hole test unit means that the orthographic projection of the dense area 301 of the first contact hole test unit onto the projection reference plane is parallel to, perpendicular to, or at a 45° angle to the orthographic projection of the dense area 401 of the second contact hole test unit onto the projection reference plane.

[0101] In one embodiment, the test structure may include a plurality of first test units 1, a plurality of second test units 2, a plurality of first contact hole test units 3, and a plurality of second contact hole test units 4.

[0102] In one embodiment, the plurality of first test units 1, the plurality of second test units 2, the plurality of first contact hole test units 3, and the plurality of second contact hole test units 4 are all located on different layers.

[0103] Specifically, the plurality of first test units 1, the plurality of second test units 2, the plurality of first contact hole test units 3, and the plurality of second contact hole test units 4 are located on different layers, which may include: the plurality of first test units 1 are located on different layers, the plurality of second test units 2 are located on different layers, the plurality of first contact hole test units 3 are located on different layers, and the plurality of second contact hole test units 4 are located on different layers; or it may include: the plurality of first test units 1, the plurality of second test units 2, the plurality of first contact hole test units 3, and the plurality of second contact hole test units 4 are located on different layers.

[0104] In some embodiments, the first contact hole test unit 3 may be located above the first test unit 1, the second test unit 2 may be located above the first contact hole test unit 3, and the second contact hole test unit 4 may be located above the second test unit 2.

[0105] Specifically, the first contact hole test unit 3 is located above the first test unit 1. This can include the first contact hole test unit 3 being directly above the first test unit 1, or it can include cases where there are other intermediate layers between the first contact hole test unit 3 and the first test unit 1. The second test unit 2 is located above the first contact hole test unit 3. This can include the second test unit 2 being directly above the first contact hole test unit 3, or it can include cases where there are other intermediate layers between the second test unit 2 and the first contact hole test unit 3. The second contact hole test unit 4 is located above the second test unit 2. This can include the second contact hole test unit 4 being directly above the second test unit 2, or it can include cases where there are other intermediate layers between the second contact hole test unit 4 and the second test unit 2.

[0106] Specifically, multiple first test units 1, multiple second test units 2, multiple first contact hole test units 3, and multiple second contact hole test units 4 are located on different layers. This corresponds to the fact that different structures within the device are located on different layers. For example, when the first test unit 1 is an active region test unit, the second test unit 2 is a first metal layer test unit, the first contact hole test unit 3 is an interlayer contact hole test unit, and the second contact hole test unit 4 is a second layer metal hole test unit, the first contact hole test unit 3 is located on the upper layer of the first test unit 1, the second test unit 2 is located on the upper layer of the first contact hole test unit 3, and the second contact hole test unit 4 is located on the upper layer of the second test unit 2. Although the different test units in the test structure of this application are located on different layers, due to the ingenious arrangement of the structure, samples of different layers can be obtained in one dicing step, avoiding the destruction of other layer structures during the preparation of a sample of a certain layer, which greatly improves the sample preparation efficiency and sample preparation success rate.

[0107] This application also provides a semiconductor device (not shown) including the test structure described in any of the above embodiments.

[0108] The semiconductor device in the above embodiments includes the test structure of any of the above embodiments, and has the same beneficial effects as the test structure. When preparing samples of this semiconductor device, it is possible to prepare samples of dense and sparse regions at the same time, and it is also possible to prepare samples of different layer test structures at the same time. One dicing can obtain analytical samples of all structural layers of the semiconductor device at the same time, saving manpower and resources and improving R&D efficiency.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A test structure, characterized in that, The test structure includes: The test unit includes a first test unit and a second test unit. Both the first test unit and the second test unit include dense areas and sparse areas. The orthographic projections of the first test unit and the second test unit on the same plane do not overlap. The contact hole testing unit includes a first contact hole testing unit and a second contact hole testing unit. Both the first contact hole testing unit and the second contact hole testing unit include dense areas and sparse areas. The orthographic projections of the first contact hole testing unit and the second contact hole testing unit on the same plane do not overlap. The first test unit, the second test unit, the first contact hole test unit, and the second contact hole test unit are all located on different layers; the test units and the contact hole test units overlap in orthographic projection on the same plane; The test unit and the contact hole test unit overlap in the orthographic projection on the same plane, including at least one of the following: the first contact hole test unit and the first test unit have partial or complete overlap in the orthographic projection on the projection reference plane; The second contact hole test unit and the first test unit have partial or complete overlap in their orthographic projections onto the projection reference plane; The first contact hole test unit and the second test unit have partial or complete overlap in their orthographic projections onto the projection reference plane; the projection reference plane is the lower surface of the substrate of the test structure. The second contact hole test unit and the second test unit have partial or complete overlap in their orthographic projection onto the projection reference plane.

2. The test structure according to claim 1, characterized in that, The first test unit includes: a first test subunit, a second test subunit, and a third test subunit; the first test subunit includes: The first test strip includes the opposing first and second ends; Multiple second test strips are arranged in parallel at intervals on opposite sides of the first test strip, extending from the first end of the first test strip to the second end of the first test strip; Multiple third test strips are arranged in parallel at intervals on opposite sides of the first test strip, extending from the second end of the first test strip to the first end of the first test strip, and there is a gap between the third test strips and the second test strip; The second test subunit includes: The fourth test strip is parallel to, perpendicular to, or at a 45° angle to the first test strip, and has a gap between it and the first test strip; Multiple fifth test strips are arranged in parallel at intervals on opposite sides of the fourth test strip, and the length of the fifth test strip is less than the length of the fourth test strip; The third test subunit includes: The sixth test strip includes a first end and a second end opposite to each other, which are perpendicular to or at a 45° angle to the first test strip, and perpendicular to or at a 45° angle to the fourth test strip; Multiple seventh test strips are arranged in parallel at intervals on opposite sides of the sixth test strip, extending from the first end of the sixth test strip to the second end of the sixth test strip.

3. The test structure according to claim 2, characterized in that, The second test unit includes: a fourth test subunit, a fifth test subunit, and a sixth test subunit; the fourth test subunit includes: The eighth test strip includes the first and second ends, which are opposite each other; Multiple ninth test strips are arranged in parallel at intervals on opposite sides of the eighth test strip, extending from the first end of the eighth test strip to the second end of the eighth test strip; Multiple tenth test strips are arranged in parallel at intervals on opposite sides of the eighth test strip, extending from the second end of the eighth test strip to the first end of the eighth test strip, and there is a gap between the tenth test strip and the ninth test strip; The fifth test subunit includes: The eleventh test strip is parallel to, perpendicular to, or at a 45° angle to the eighth test strip, and is spaced apart from the eighth test strip; Multiple twelfth test strips are arranged in parallel at intervals on opposite sides of the eleventh test strip, and the length of the twelfth test strip is shorter than the length of the eleventh test strip; The sixth test subunit includes: The thirteenth test strip includes a first end and a second end that are opposite each other, perpendicular to or at a 45° angle to the eighth test strip, and perpendicular to or at a 45° angle to the eleventh test strip; Multiple fourteenth test strips are arranged in parallel at intervals on opposite sides of the thirteenth test strip, extending from the first end of the thirteenth test strip to the second end of the thirteenth test strip.

4. The test structure according to claim 3, characterized in that, The spacing between adjacent second test strips, the spacing between adjacent third test strips, the spacing between the second test strip and the first test strip, the spacing between the third test strip and the first test strip, the spacing between adjacent fifth test strips, the spacing between the fifth test strip and the fourth test strip, the spacing between adjacent seventh test strips, the spacing between the seventh test strip and the sixth test strip, the spacing between adjacent ninth test strips, the spacing between adjacent tenth test strips, the spacing between the ninth test strip and the eighth test strip, the spacing between adjacent twelfth test strips, the spacing between the twelfth test strip and the eleventh test strip, the spacing between adjacent fourteenth test strips, and the spacing between the fourteenth test strip and the thirteenth test strip all satisfy the minimum design rule.

5. The test structure according to claim 1, characterized in that, Both the dense area and the sparse area of ​​the first contact hole test unit are provided with multiple first contact holes. The distance between adjacent first contact holes in the dense area of ​​the first contact hole test unit is smaller than the distance between adjacent first contact holes in the sparse area of ​​the first contact hole test unit, and smaller than the distance between the dense area and the sparse area of ​​the first contact hole test unit.

6. The test structure according to claim 5, characterized in that, Multiple second contact holes are provided in both the dense area and the sparse area of ​​the second contact hole test unit. The spacing between adjacent second contact holes in the dense area of ​​the second contact hole test unit is smaller than the spacing between adjacent second contact holes in the sparse area of ​​the second contact hole test unit, and smaller than the spacing between the dense area and the sparse area of ​​the second contact hole test unit.

7. The test structure according to claim 6, characterized in that, The spacing between adjacent first contact holes in the dense area of ​​the first contact hole test unit and the spacing between adjacent second contact holes in the dense area of ​​the second contact hole test unit both meet the minimum design rule.

8. The test structure according to any one of claims 1 to 7, characterized in that, The test structure includes multiple first test units, multiple second test units, multiple first contact hole test units, and multiple second contact hole test units.

9. The test structure according to claim 8, characterized in that, The plurality of first test units, the plurality of second test units, the plurality of first contact hole test units, and the plurality of second contact hole test units are located in different layers.

10. A semiconductor device, characterized in that, Includes the test structure as described in any one of claims 1 to 9.

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