Test structure and manufacturing method and test method thereof
By designing a test structure that spans multiple metal layers and integrating dielectric layer breakdown structures of the same and different layers, the problem of test structure space limitation and low efficiency caused by increased chip integration is solved, and efficient reliability risk identification and complex trace simulation are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-24
AI Technical Summary
As chip integration increases, wafer space becomes precious. Existing test structures cannot effectively simulate complex traces and require multiple tests, resulting in a complicated and inefficient testing process that cannot quickly identify reliability risks.
Design a test structure including a first connection structure and a second connection structure extending along a first direction and spaced apart, spanning multiple metal layers, integrating dielectric layer breakdown structures of the same and different layers, and optimizing the integration and reliability identification of the test structure.
It improves the integration of the test structure, enables rapid identification of reliability risks, saves space, and can simulate the complex routing of actual circuits, thereby improving test efficiency.
Smart Images
Figure CN121729044A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to a test structure and its manufacturing and testing methods. Background Technology
[0002] As chip integration becomes increasingly sophisticated, wafer space (also known as wafer area) becomes increasingly precious; for example, the space for placing test structures is limited. In the performance testing of inter-metal dielectric (IMD) layers, a test structure that monitors multiple properties of the IMD layer is of great practical significance. Summary of the Invention
[0003] In view of this, embodiments of this application provide a test structure, a method for manufacturing the same, and a test method thereof.
[0004] In a first aspect, embodiments of this application provide a test structure, which includes a first pad, a second pad, and at least one structural unit located between the first pad and the second pad; wherein, the structural unit includes a first connection structure and a second connection structure extending along a first direction and spaced apart; the first connection structure is connected to the first pad and includes a plurality of alternately connected first metal lines and at least one first via; the second connection structure is connected to the second pad and includes a plurality of alternately connected second metal lines and at least one second via; wherein, the structural unit includes a first unit and a second unit; the first unit includes first metal lines and second metal lines located in the same metal layer and adjacent to each other; the second unit includes an overlapping portion between the first metal lines and second metal lines located in two adjacent metal layers.
[0005] In some embodiments, the test structure includes a first metal layer to a Pth metal layer stacked sequentially; P is a positive integer greater than 1; the first metal layer to the Pth metal layer each have a first metal line and a second metal line; a first via and a second via are respectively provided between two adjacent metal layers of the first metal layer to the Pth metal layer; wherein the first metal layer to the Pth metal layer each include a first unit; and two adjacent metal layers of the first metal layer to the Pth metal layer each include a second unit.
[0006] In some embodiments, the test structure includes a first metal layer to a Qth metal layer stacked sequentially; Q is a positive integer greater than 2; a plurality of first metal lines are located in the first metal layer to the (Q-1)th metal layer, and a plurality of first vias are located between adjacent metal layers in the first metal layer to the (Q-1)th metal layer; a plurality of second metal lines are located in the second metal layer to the Qth metal layer, and a plurality of second vias are located between adjacent metal layers in the second metal layer to the Qth metal layer; wherein, the first metal layer has one first metal line; the second metal layer to the (Q-1)th metal layer has two first metal lines; the second metal layer has one second metal line; the third metal layer to the Qth metal layer has two second metal lines; all the second metal lines in the second metal layer to the (Q-1)th metal layer are located between two first metal lines; wherein, the second metal layer to the (Q-1)th metal layer each includes two first units; the first metal layer and the second metal layer each include one second unit; adjacent metal layers in the second metal layer to the Qth metal layer each include two second units.
[0007] In some embodiments, the test structure includes a first metal layer, a second metal layer, and a third metal layer stacked sequentially; a plurality of first metal lines are located in the first metal layer and the second metal layer, and a plurality of first vias are located between the first metal layer and the second metal layer; a plurality of second metal lines are located in the second metal layer and the third metal layer, and a plurality of second vias are located between the second metal layer and the third metal layer; wherein, the second metal layer includes at least one first unit; the first metal layer and the second metal layer include at least one second unit; and the second metal layer and the third metal layer include at least one second unit.
[0008] In some embodiments, the second metal layer has a plurality of alternating first metal lines and a plurality of second metal lines; wherein the second metal layer includes at least three first units; the first metal layer and the second metal layer include a first number of second units; the first number is the number of the plurality of first metal lines in the second metal layer; the second metal layer and the third metal layer include a second number of second units; the second number is the number of the plurality of second metal lines in the second metal layer.
[0009] In some embodiments, the test structure includes a plurality of structural units arranged along a second direction; the second direction intersects with the first direction.
[0010] In some embodiments, the test structure includes a plurality of structural units arranged along a third direction; the third direction intersects with the second direction and the first direction, respectively.
[0011] In some embodiments, the first metal wire and the second metal wire of the first unit have a minimum spacing specified by design rules.
[0012] In some embodiments, the characteristic dimension of the width of the first metal wire and / or the second metal wire is the minimum line width or minimum wrapping size specified by the design rules; wherein, the connection between the first metal wire and the first via satisfies the minimum wrapping size of the first metal wire to the first via specified by the design rules.
[0013] Secondly, embodiments of this application provide a method for manufacturing a test structure, the method comprising: forming at least one structural unit; wherein the structural unit includes a first connection structure and a second connection structure extending along a first direction and spaced apart; the first connection structure includes a plurality of alternately connected first metal lines and at least one first via; the second connection structure includes a plurality of alternately connected second metal lines and at least one second via; wherein the structural unit includes a first unit and a second unit; the first unit includes first metal lines and second metal lines located in the same metal layer and adjacent to each other; the second unit includes an overlapping portion between first metal lines and second metal lines located in two adjacent metal layers; a first pad connected to the first connection structure is formed on a first side of the structural unit; a second pad connected to the second connection structure is formed on a second side of the structural unit; the first side and the second side are two opposite sides of the structural unit in the first direction.
[0014] Thirdly, embodiments of this application provide a testing method. The test object of the testing method includes a test structure as described in any of the first aspects, or a test structure obtained according to the manufacturing method of the second aspect. The testing method includes: applying a first voltage and a second voltage to a first pad and a second pad of the test structure, respectively; the first voltage being less than the second voltage; acquiring a test current flowing through the first pad or the second pad, and a test voltage between the first pad and the second pad; and obtaining a current-voltage characteristic curve of the test structure under the first voltage and the second voltage conditions based on the test current and the test voltage; the current-voltage characteristic curve includes the voltage breakdown (VBD) of the test structure.
[0015] In various embodiments of this application, by optimizing the design of the test structure, the structural unit of the test structure includes a first connection structure and a second connection structure that extend along a first direction and are spaced apart. Both the first connection structure and the second connection structure span multiple metal layers. On the one hand, this can improve the integration of the test structure. On the other hand, it can simulate the complex traces that exist in actual circuits, and can integrate dielectric layer breakdown structures (such as the first unit and the second unit) between the same metal layer and between different metal layers into a single test structure (such as a structural unit). This allows for faster identification of potential reliability risks and saves space in the test structure. Attached Figure Description
[0016] Figure 1 A schematic diagram of a dielectric layer breakdown structure between metal lines located in the same metal layer, provided in an embodiment of this application; Figure 2 A schematic diagram of a dielectric layer breakdown structure between metal lines in two adjacent metal layers, provided in an embodiment of this application; Figure 3 One of the schematic diagrams of the test structure provided in the embodiments of this application; Figure 4 for Figure 3 Schematic diagrams of some deformed structures of the test structure shown; Figure 5 A second schematic diagram of the test structure provided in the embodiments of this application; Figure 6 Schematic diagram three of the test structures provided in the embodiments of this application; Figure 7 Schematic diagram four of the test structures provided in the embodiments of this application; Figure 8 A schematic flowchart illustrating the manufacturing method of the test structure provided in this application embodiment; Figures 9A to 9D A cross-sectional schematic diagram of an exemplary manufacturing process for a test structure provided in an embodiment of this application. Detailed Implementation
[0017] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.
[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.
[0020] Figure 1 This is a schematic diagram of a dielectric layer breakdown structure between metal lines in the same metal layer, provided in an embodiment of this application. Figure 1 (a) in the diagram is a top-view plan view. Figure 1 Figure (b) is a schematic diagram of Figure (a) along section AA.
[0021] refer to Figure 1 The dielectric breakdown structure between metal lines in the same metal layer includes a periodic capacitor structure in a plane formed by the comb electrodes and the dielectric layer between them, used for reliability testing of dielectric breakdown between metal lines in the same metal layer. Exemplarily, the metal layer Mn includes a first pad PAD1, a first electrode 101, a second pad PAD2, a second electrode 102, and a dielectric layer between the first electrode 101 and the second electrode 102. Figure 1 (Not shown); the first electrode 101 and the second electrode 102 extend along a first direction (X direction); a plurality of first electrodes 101 and a plurality of second electrodes 102 are arranged alternately along a second direction (Y direction); the first electrode 101 is connected to a first pad PAD1; the second electrode 102 is connected to a second pad PAD2. In this way, the dielectric layer breakdown structure can be used to test the reliability of dielectric layer breakdown between the first electrode 101 and the second electrode 102 in the metal layer Mn.
[0022] Figure 2 This is a schematic diagram of a dielectric layer breakdown structure between metal lines in two adjacent metal layers, provided in an embodiment of this application. Figure 2 (a) in the diagram is a top-view plan view. Figure 2 Figure (b) is a schematic diagram of Figure (a) along the BB section.
[0023] refer to Figure 2 The dielectric breakdown structure between metal lines in different metal layers includes a capacitor structure composed of overlapping comb electrodes and the dielectric layer between them, used for reliability testing of dielectric breakdown between metal lines in two metal layers. For example, metal layer Mn includes a second pad PAD2 and a second electrode 202; the second electrode 202 extends along a first direction (X direction); multiple second electrodes 202 are spaced apart along a second direction (Y direction); the second electrode 202 is connected to the second pad PAD2; metal layer Mn+1 on metal layer Mn includes a first pad PAD1 and a first electrode 201; the first electrode 201 extends along the first direction (X direction); multiple first electrodes 201 are spaced apart along the second direction (Y direction); the first electrode 201 is connected to the first pad PAD1; the first electrode 201 and the second electrode 202 have an overlapping portion in the stacking direction (Z direction), and this overlapping portion and the dielectric layer between them ( Figure 2The capacitor structure is not shown. Thus, the dielectric breakdown structure can be used to test the reliability of dielectric breakdown between the second electrode 202 in metal layer Mn and the first electrode 201 in metal layer Mn+1.
[0024] For complex chip traces, various structures requiring reliability testing exist within a single metal layer. Each dielectric layer breakdown structure needs to be tested individually, necessitating the design of numerous test structures and repeated testing to complete the reliability testing for the entire metal layer. This process is cumbersome and inefficient. Furthermore, the relatively simple traces for each dielectric layer breakdown structure cannot simulate the complex traces of an actual chip. As chip integration increases, wafer space becomes increasingly precious; for example, the space for placing test structures is limited. In the performance testing of inter-metal dielectric layers, a single test structure comprising multiple dielectric layer breakdown structures is of significant practical value for monitoring various performance characteristics of the inter-metal dielectric layer.
[0025] In view of this, embodiments of this application provide a test structure, a method for manufacturing the same, and a test method thereof.
[0026] Figure 3 This is one of the schematic diagrams of the test structure provided in the embodiments of this application. Figure 4 for Figure 3 The diagram shows some deformed structures of the test structure shown. Figure 5 This is a second schematic diagram of the test structure provided in an embodiment of this application. Figure 6 This is the third schematic diagram of the test structure provided in the embodiments of this application. Figure 7 This is the fourth schematic diagram of the test structure provided in the embodiments of this application. For Figure 4 , Figure 5 , Figure 6 or Figure 7 For layers, areas, and components not marked in the text, please refer to... Figure 3 Understand the layers, areas, and components marked in the text.
[0027] Firstly, embodiments of this application provide a test structure, with reference to Figure 3 , Figure 4 , Figure 5 , Figure 6 or Figure 7The test structure 300 includes a first pad PAD1, a second pad PAD2, and at least one structural unit 302 located between the first pad PAD1 and the second pad PAD2; wherein, the structural unit 302 includes a first connection structure 304 and a second connection structure 306 extending along a first direction and spaced apart; the first connection structure 304 connects to the first pad PAD1 and includes a plurality of alternately connected first metal lines 308 and at least one first via 310; the second connection structure 306 connects to the second pad PAD2 and includes a plurality of alternately connected second metal lines 312 and at least one second via 314; wherein, the structural unit 302 includes a first unit 302a and a second unit 302b; the first unit 302a includes first metal lines 308 and second metal lines 312 located in the same metal layer and adjacent to each other; the second unit 302b includes an overlapping portion between the first metal lines 308 and second metal lines 312 located in two adjacent metal layers. In this embodiment, by optimizing the design of the test structure, the structural units of the test structure include a first connection structure and a second connection structure that extend along a first direction and are spaced apart. Both the first connection structure and the second connection structure span multiple metal layers. On the one hand, this can improve the integration of the test structure; on the other hand, it can simulate the complex traces existing in actual circuits and integrate the dielectric layer breakdown structures between the same metal layer and between different metal layers of the subsequent multi-layer metal layers into a single test structure. This allows for faster identification of potential reliability risks and saves space in the test structure.
[0028] For ease of description, the first and second directions involved in the embodiments of this application refer to two directions parallel to the top / bottom surface of the test structure, and the first and second directions intersect (e.g., are orthogonal); the third direction refers to the stacking direction of each layer of the test structure. For example, the first direction can be represented as the X direction in the figures; the second direction can be represented as the Y direction in the figures; and the third direction can be represented as the Z direction in the figures.
[0029] In some embodiments, the materials of the metal lines in each metal layer and the materials of the vias in each conductive layer include, but are not limited to, tungsten, cobalt, nickel, copper, aluminum, polysilicon, doped silicon, silicide, nitride, or any combination thereof. Exemplarily, the materials of the first and second metal lines may include metals such as copper or tungsten. Exemplarily, the materials of the first and second vias may include metals such as copper or tungsten. In some embodiments, the materials of the first and second pads can be understood with reference to the materials of the metal lines, and will not be elaborated further here.
[0030] In some embodiments, the materials of the dielectric layers between metal lines in the same metal layer and between metal lines in different metal layers include, but are not limited to, silicon oxide, silicon nitride, silicon oxynitride, or any combination thereof. Exemplarily, the materials of the dielectric layers between metal lines in the same metal layer and between metal lines in different metal layers may include dielectric materials with a dielectric constant (k value) lower than 3.8.
[0031] Figure 3 (a) in the diagram is a top-view plan view. Figure 3 Figure (b) is a schematic diagram of Figure (a) along the CC section. Figure 3 Figure (c) is an enlarged view of region P101 in Figure (b).
[0032] refer to Figure 3 In Figure (b) of the diagram, in some embodiments, the test structure 300 includes a first metal layer Mn, a second metal layer Mn+1, and a third metal layer Mn+2 stacked sequentially; a plurality of first metal lines 308 are located in the first metal layer Mn and the second metal layer Mn+1, and a plurality of first vias 310 are located between the first metal layer Mn and the second metal layer Mn+1; a plurality of second metal lines 312 are located in the second metal layer Mn+1 and the third metal layer Mn+2, and a plurality of second vias 314 are located between the second metal layer Mn+1 and the third metal layer Mn+2; wherein the second metal layer Mn+1 includes at least one first unit 302a; the first metal layer Mn and the second metal layer Mn+1 include at least one second unit 302b; and the second metal layer Mn+1 and the third metal layer Mn+2 include at least one second unit 302b. In this embodiment of the application, a plurality of first vias 310 are located in the second conductive layer Vn+1, and a plurality of second vias 314 are located in the third conductive layer Vn+2.
[0033] refer to Figure 3 In Figure (b) of the figure, in some embodiments, the second metal layer Mn+1 has a plurality of alternating first metal lines 308 and a plurality of second metal lines 312; wherein the second metal layer Mn+1 includes at least three first units 302a; the first metal layer Mn and the second metal layer Mn+1 include a first number of second units 302b; the first number is the number of the plurality of first metal lines 308 in the second metal layer Mn+1; the second metal layer Mn+1 and the third metal layer Mn+2 include a second number of second units 302b; the second number is the number of the plurality of second metal lines 312 in the second metal layer Mn+1.
[0034] Figure 4 The structure shown in Figure (a) includes a first unit and two second units. Figure 4The structure shown in Figure (b) includes two first units and three second units. For details regarding the first and second units, please refer to [reference needed]. Figure 3 The relevant explanations in Figure (b) are for reference only and will not be repeated here.
[0035] refer to Figure 4 In Figure (a), in some embodiments, the second metal layer Mn+1 has a first metal line 308 and a second metal line 312 spaced apart; wherein the second metal layer Mn+1 includes a first unit 302a; the first metal layer Mn and the second metal layer Mn+1 include a second unit 302b; the second metal layer Mn+1 and the third metal layer Mn+2 include a second unit 302b.
[0036] refer to Figure 4 In Figure (b) of the diagram, in some embodiments, the second metal layer Mn+1 has two alternating first metal lines 308 and one second metal line 312, or the second metal layer Mn+1 has one alternating first metal line 308 and two second metal lines 312. Exemplarily, as shown... Figure 4 As shown in Figure (b), the second metal layer Mn+1 includes two first units 302a; the first metal layer Mn and the second metal layer Mn+1 include one second unit 302b; the second metal layer Mn+1 and the third metal layer Mn+2 include two second units 302b.
[0037] Compared to Figure 4 The structure shown in Figure (a) has only one first unit. Figure 4 The structure shown in Figure (b) and Figure 3 The structure shown in Figure (b) has multiple first units. Thus, compared to a single detection by a single first unit, multiple first units can more accurately detect the dielectric breakdown performance between metal lines in the same metal layer.
[0038] Compared to Figure 4 The structure shown in Figure (a) has only one first unit. Figure 4 The structure shown in Figure (b) includes only one second unit in the first metal layer Mn and the second metal layer Mn+1. Figure 3The structure shown in Figure (b) has multiple first units, and multiple second units are present between any two adjacent metal layers (between the first metal layer Mn and the second metal layer, or between the second metal layer Mn and the third metal layer). Thus, compared to a single detection using a single first unit, the multiple first units in the second metal layer can more accurately detect the dielectric breakdown performance between the metal lines in the second metal layer; similarly, compared to a single detection using a single second unit, the multiple second units between any two adjacent metal layers can more accurately detect the dielectric breakdown performance between the metal lines of the two metal layers.
[0039] Figure 5 The test structure in Figure (a) is a schematic diagram of the case where the first and second metal layers are stacked sequentially. Figure 5 The test structure in Figure (b) is a schematic diagram of the case where the first to third metal layers are stacked sequentially. Figure 5 Figure (c) shows a schematic diagram of the test structure located in a configuration where the first to fifth metal layers are stacked sequentially. For details regarding the first and second units, please refer to [reference needed]. Figure 3 The relevant explanations in Figure (b) are for reference only and will not be repeated here.
[0040] refer to Figure 5 In some embodiments, the test structure includes a first metal layer to a Pth metal layer stacked sequentially; P is a positive integer greater than 1; each of the first to Pth metal layers has a first metal line and a second metal line; each of the first to Pth metal layers has a first via and a second via between adjacent metal layers; wherein each of the first to Pth metal layers includes a first unit; each of the first to Pth metal layers includes a second unit. In this embodiment, each metal layer has a first unit, and each of any two adjacent metal layers has a second unit. A single structural unit can detect both the dielectric breakdown performance between metal lines in each metal layer and the dielectric breakdown performance between metal lines in any two adjacent metal layers. In other words, a single structural unit can detect both the dielectric breakdown performance between metal lines in any same metal layer and the dielectric breakdown performance between metal lines in any adjacent different metal layers.
[0041] refer to Figure 5 In Figure (a), for example, the structural unit of the test structure is located in the case of two metal layers (the first metal layer Mn and the second metal layer Mn+1) stacked in sequence.
[0042] refer to Figure 5In Figure (b), for example, the structural unit of the test structure is located in a configuration of three metal layers stacked sequentially (first metal layer Mn, second metal layer Mn+1 and third metal layer Mn+2).
[0043] refer to Figure 5 In Figure (c), for example, the structural unit of the test structure is located in a configuration of five metal layers stacked sequentially (first metal layer Mn, second metal layer Mn+1, third metal layer Mn+2, fourth metal layer Mn+3 and fifth metal layer Mn+4).
[0044] It is understandable that the structural units of the test structure are located in four or more layers of metal stacked sequentially, which can be referred to as... Figure 5 The meaning of (c) is to be understood, and the specific details will not be elaborated here.
[0045] Figure 6 The test structure in Figure (a) is a schematic diagram of the case where the first to third metal layers are stacked sequentially. Figure 6 Figure (b) shows a schematic diagram of the test structure located in the case of sequentially stacked metal layers from the first to the fifth. For details regarding the first and second units, please refer to [reference needed]. Figure 3 The relevant explanations in Figure (b) are for reference only and will not be repeated here.
[0046] refer to Figure 6In some embodiments, the test structure includes a first metal layer to a Qth metal layer stacked sequentially; Q is a positive integer greater than 2; a plurality of first metal lines are located in the first metal layer to the (Q-1)th metal layer, and a plurality of first vias are located between adjacent metal layers in the first metal layer to the (Q-1)th metal layer; a plurality of second metal lines are located in the second metal layer to the Qth metal layer, and a plurality of second vias are located between adjacent metal layers in the second metal layer to the Qth metal layer; wherein, the first metal layer has one first metal line; the... The second to Q-1 metal layers each have two first metal lines; the second metal layer has one second metal line; the third to Q metal layers each have two second metal lines; all second metal lines in the second to Q-1 metal layers are located between two first metal lines; wherein, the second to Q-1 metal layers each include two first units; the first and second metal layers each include one second unit; adjacent metal layers in the second to Q metal layers each include two second units. In this embodiment, each metal layer in the intermediate metal layer (the metal layer between the first and Q metal layers) has two first units, and there are two second units between any two adjacent metal layers in the intermediate metal layer. The dielectric breakdown performance between metal lines in each metal layer in the intermediate metal layer can be detected by the two first units, and the dielectric breakdown performance between metal lines in any two adjacent metal layers in the intermediate metal layer can be detected by the two second units.
[0047] refer to Figure 6 In Figure (a), for example, the structural unit of the test structure is located in a configuration of three metal layers stacked sequentially (first metal layer Mn, second metal layer Mn+1 and third metal layer Mn+2).
[0048] refer to Figure 6 In Figure (b), for example, the structural unit of the test structure is located in a configuration of five metal layers stacked sequentially (first metal layer Mn, second metal layer Mn+1, third metal layer Mn+2, fourth metal layer Mn+3 and fifth metal layer Mn+4).
[0049] It is understandable that the structural units of the test structure are located in four or more layers of metal stacked sequentially, which can be referred to as... Figure 6 The details of (b) in the text will not be elaborated here.
[0050] Continue to refer to Figure 3 In Figure (a), in some embodiments, the test structure 300 includes a plurality of structural units 302 arranged along a second direction; the second direction intersects the first direction.
[0051] It should be noted that the number of structural units 302 arranged along the second direction is not limited to... Figure 3 The seven structural units 302 arranged along the second direction can be 2, 3, 4, 5, 6 or more than 7 (e.g., 8, 9, etc.).
[0052] In some embodiments, the internal layout between at least two structural units 302 of the plurality of structural units 302 arranged along the second direction may be the same or different. Exemplarily, in the second direction, the internal layout between the plurality of structural units 302 may be the same. For example, in the case where the structural units of the test structure are located in three sequentially stacked metal layers, each of the plurality of structural units 302 may be one of the following internal layouts: Figure 3 The internal layout shown in Figure (b) is as follows: Figure 4 The internal layout shown in Figure (a) is as follows: Figure 4 The internal layout shown in Figure (b) is as follows: Figure 5 The internal layout shown in Figure (b) is as follows: Figure 6 The internal layout is shown in Figure (a). Exemplarily, in the second direction, the internal layout between the two structural units 302 can be different, and the two structural units 302 can be two of the following internal layouts: Figure 3 The internal layout shown in Figure (b) is as follows: Figure 4 The internal layout shown in Figure (a) is as follows: Figure 4 The internal layout shown in Figure (b) is as follows: Figure 5 The internal layout shown in Figure (b) is as follows: Figure 6 The internal layout is shown in Figure (a).
[0053] In some embodiments, in the second direction, the spacing between two adjacent structural units 302 is greater than the minimum spacing D1 specified by the design rules.
[0054] refer to Figure 7 In some embodiments, the test structure 300 includes a plurality of structural units 302 arranged along a third direction; the third direction intersects with the second direction and the first direction, respectively.
[0055] For example, the test structure 300 includes a first metal layer Mn, a second conductive layer Vn+1, a second metal layer Mn+1, a third conductive layer Vn+2, a third metal layer Mn+2, a fourth conductive layer Vn+3, a fourth metal layer Mn+3, a fifth conductive layer Vn+4, a fifth metal layer Mn+4, a sixth conductive layer Vn+5, and a sixth metal layer Mn+5 stacked sequentially; the test structure 300 includes two structural units 302, one of which is located in the first metal layer Mn, the second conductive layer Vn+1, the second metal layer Mn+1, the third conductive layer Vn+2, and the third metal layer Mn+2, and the other structural unit 302 is located in the fourth metal layer Mn+3, the fifth conductive layer Vn+4, the fifth metal layer Mn+4, the sixth conductive layer Vn+5, and the sixth metal layer Mn+5.
[0056] In some embodiments, the internal layout between at least two structural units 302 arranged along a third direction may be the same or different. For example, in the third direction, the internal layout between the multiple structural units 302 may be the same. For instance, in the case where the structural units of the test structure are located in three sequentially stacked metal layers, each of the multiple structural units 302 may be one of the following internal layouts: Figure 3 The internal layout shown in Figure (b) is as follows: Figure 4 The internal layout shown in Figure (a) is as follows: Figure 4 The internal layout shown in Figure (b) is as follows: Figure 5 The internal layout shown in Figure (b) is as follows: Figure 6 The internal layout is shown in Figure (a). Exemplarily, in the third direction, the internal layout between the two structural units 302 can be different. For example, in the case where the structural units of the test structure are located in three sequentially stacked metal layers, the two structural units 302 can be two of the following internal layouts: Figure 3 The internal layout shown in Figure (b) is as follows: Figure 4 The internal layout shown in Figure (a) is as follows: Figure 4 The internal layout shown in Figure (b) is as follows: Figure 5 The internal layout shown in Figure (b) is as follows: Figure 6 The internal layout is shown in Figure (a).
[0057] refer to Figure 7 In some embodiments, in the second direction, the spacing between two adjacent structural units 302 is equal to the thickness of a conductive layer. For example, the spacing between two adjacent structural units 302 is equal to the thickness of a fourth conductive layer Vn+3.
[0058] Continue to refer to Figure 3In Figure (c), in some embodiments, the first metal line 308 and the second metal line 312 of the first unit have a minimum spacing D1 specified by design rules.
[0059] Continue to refer to Figure 3 In Figure (c), in some embodiments, the characteristic dimension of the width of the first metal line 308 and / or the second metal line 312 is the minimum line width or minimum wrapping size specified by the design rules; wherein, the connection between the first metal line 308 and the first through hole 310 satisfies the minimum wrapping size D2 of the first metal line 308 to the first through hole 310 specified by the design rules.
[0060] In some embodiments, if more attention is paid to the performance testing of the dielectric layer between the metal lines of a single metal layer in the test structure, the test structure can be designed as follows: Figure 3 The test structure shown can incorporate as many first cells as possible within the metal layer. This allows for more accurate detection of dielectric breakdown performance between metal lines within the same metal layer, compared to a single first cell detection.
[0061] In some embodiments, if greater emphasis is placed on the performance testing of the dielectric layer between metal lines in certain multilayer metal layers of the test structure (e.g., a metal layer in an intermediate position (a metal layer between the top and bottom metal layers in a third-direction orientation)), the test structure can be designed as follows: Figure 6 The test structure shown can have two first units placed within each metal layer of the intermediate metal layer (the metal layer between the top and bottom metal layers in the third direction). Thus, while focusing on a portion of the multi-layered metal structure, compared to a single detection by a single first unit, two first units can more accurately detect the dielectric breakdown performance between metal lines in the same metal layer.
[0062] In some embodiments, if greater emphasis is placed on the performance testing of the dielectric layer between the metal lines of all metal layers in the test structure, the test structure can be designed as follows: Figure 5 The test structure shown can have a first unit set in each of all metal layers. Thus, while considering all the metal layers of the test structure, a single structural unit can be used to test both the dielectric breakdown performance between metal lines in any same metal layer and the dielectric breakdown performance between metal lines in any adjacent, different metal layers.
[0063] Figure 8 This is a schematic flowchart illustrating the manufacturing method of the test structure provided in an embodiment of this application. Figures 9A to 9D A cross-sectional schematic diagram of an exemplary manufacturing process for a test structure provided in an embodiment of this application.
[0064] Secondly, embodiments of this application provide a method for manufacturing a test structure, referring to... Figure 8 The manufacturing method includes the following steps: Step S101: Form at least one structural unit; wherein, the structural unit includes a first connection structure and a second connection structure extending along a first direction and spaced apart; the first connection structure includes a plurality of alternately connected first metal lines and at least one first via; the second connection structure includes a plurality of alternately connected second metal lines and at least one second via; wherein, the structural unit includes a first unit and a second unit; the first unit includes first metal lines and second metal lines located in the same metal layer and adjacent to each other; the second unit includes an overlapping portion between first metal lines and second metal lines located in two adjacent metal layers; Step S102: On the first side of the structural unit, a first pad connected to the first connection structure is formed; on the second side of the structural unit, a second pad connected to the second connection structure is formed; the first side and the second side are opposite sides of the structural unit in the first direction.
[0065] refer to Figure 9A A first metal layer Mn is formed, the first metal layer Mn includes a plurality of first metal lines 308; the first metal lines 308 extend along a first direction.
[0066] refer to Figure 9B On the first metal layer Mn, a second conductive layer Vn+1 and a second metal layer Mn+1 are sequentially formed; the second conductive layer Vn+1 includes at least one first via 310; the second metal layer Mn+1 includes at least one first metal line 308 and at least one second metal line 312; the first metal line 308 and the second metal line 312 both extend along a first direction; wherein, the first via 310 connects the first metal line 308 of the first metal layer Mn and the first metal line 308 of the second metal layer Mn+1 to obtain a first connection structure.
[0067] refer to Figure 9C On the second metal layer Mn+1, a third conductive layer Vn+2 and a third metal layer Mn+2 are formed sequentially; the third conductive layer Vn+2 includes at least one second via 314; the third metal layer Mn+2 includes a plurality of second metal lines 312; the second metal lines 312 all extend along a first direction; wherein, the second via 314 connects the second metal lines 312 of the second metal layer Mn+1 and the second metal lines 312 of the third metal layer Mn+2 to obtain a second connection structure.
[0068] refer to Figure 9DOn the first side of the structural unit, a first pad PAD1 is formed that is connected to the first connection structure; on the second side of the structural unit, a second pad PAD2 is formed that is connected to the second connection structure; the first side and the second side are two opposite sides of the structural unit in the first direction.
[0069] Figures 9A to 9D The test structure obtained by the manufacturing method of the test structure shown can be understood as Figure 3 The test structure is shown in Figure (b). Figure 4 The test structure shown in Figure (a) is as follows: Figure 4 The test structure shown in Figure (b) is as follows: Figure 5 The test structure shown in Figure (b) or Figure 6 The manufacturing method of the test structure shown in Figure (a) can be referred to Figure 3 The manufacturing method of the test structure shown in Figure (b) is explained here, and the specific details will not be repeated here.
[0070] The test structure obtained by the manufacturing method of the test structure provided in the second aspect of this application is similar to the test structure provided in the first aspect above. For technical features not disclosed in detail in the embodiments of this application, please refer to the test structure in the embodiments provided in the first aspect above for understanding. Here, they will not be repeated.
[0071] Thirdly, embodiments of this application provide a testing method. The test object of the testing method includes a test structure as described in any of the first aspects, or a test structure obtained according to the manufacturing method of the second aspect. The testing method includes: applying a first voltage and a second voltage to a first pad and a second pad of the test structure, respectively; the first voltage being less than the second voltage; acquiring a test current flowing through the first pad or the second pad, and a test voltage between the first pad and the second pad; and obtaining a current-voltage characteristic curve of the test structure under the first voltage and the second voltage conditions based on the test current and the test voltage; the current-voltage characteristic curve including the breakdown voltage of the test structure.
[0072] In this embodiment, the principle of the testing method is as follows: For two adjacent metal layers, as the voltage difference between the upper and lower adjacent metal layers of the test structure increases, the electric field strength between the upper and lower metal layers also continuously increases. When the electric field strength increases to a limit value, the interlayer dielectric between the upper and lower metal layers will break down, forming a current path. At this time, the leakage current will increase instantaneously by at least one order of magnitude, thus determining that the test is complete. The voltage value at this time is called the breakdown voltage. Similarly, for two adjacent metal lines in the same metal layer, as the voltage difference between the two metal lines of the test structure increases, the electric field strength between the two metal lines will also continuously increase. When the electric field strength increases to a limit value, the interlayer dielectric between the two metal lines will break down, forming a current path. At this time, the leakage current will increase instantaneously by at least one order of magnitude, thus determining that the test is complete. The voltage value at this time is called the breakdown voltage.
[0073] For example, the test method includes applying a first voltage and a second voltage to a first pad and a second pad of the test structure, respectively. The first voltage can be a ground voltage (e.g., 0V), and the second voltage can be a voltage that is gradually increased in steps (positive voltage) starting from the ground voltage. The current (the sum of leakage currents flowing through the test structure) of the first and second pads is measured at each step increase. Due to the inherent characteristics of the dielectric layer, the leakage current gradually increases with the increase of the second voltage. When the second voltage reaches a certain value (i.e., the breakdown voltage), the dielectric layer itself cannot withstand the applied electrical stress, and the dielectric layer breaks down. When this dielectric layer breaks down, the leakage current increases rapidly (at least an order of magnitude larger than the current when the dielectric layer is not broken down). The voltage at the last measurement before the dielectric layer breaks down is recorded as the breakdown voltage.
[0074] In some embodiments, the test method further includes: applying a first voltage and a second voltage to the first pad and the second pad of the test structure, respectively. The first voltage can be a ground voltage (e.g., 0V), and the second voltage can be a constant voltage. Using time as a variable, the current (the sum of leakage current flowing through the test structure) of the first and second pads is measured every unit of time. After a certain period of time, under constant electrical stress, the dielectric layer breaks down at a specific time, causing a rapid increase in leakage current. The time elapsed before the dielectric layer breaks down is recorded as Time Dependent Dielectric Breakdown (TDDB).
[0075] It is understood that the first pad and the second pad in this paper are two opposing pads, and their positions can be interchanged. It is also understood that the first voltage and the second voltage in this paper are two opposing voltages; alternatively, the second voltage and the first voltage can be applied to the first pad and the second pad of the test structure respectively, with the first voltage being less than the second voltage.
[0076] The test object of the test method provided in the third aspect of this application includes any of the test structures in the first aspect, or the test structure obtained according to the manufacturing method of the second aspect. For technical features not disclosed in detail in the embodiments of this application, please refer to the embodiments of the first and second aspects above for understanding, and will not be repeated here.
[0077] The above description is only a preferred embodiment of this DIANYA application and does not limit the scope of protection of this application. All equivalent structural transformations made under the inventive concept of this application using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.
Claims
1. A test structure, characterized in that, It includes a first pad, a second pad, and at least one structural unit located between the first pad and the second pad; The structural unit includes a first connection structure and a second connection structure extending along a first direction and spaced apart; the first connection structure is connected to the first pad and includes a plurality of alternately connected first metal lines and at least one first via; the second connection structure is connected to the second pad and includes a plurality of alternately connected second metal lines and at least one second via. The structural unit includes a first unit and a second unit; the first unit includes a first metal line and a second metal line located in the same metal layer and adjacent to each other; the second unit includes an overlapping portion between the first metal line and the second metal line located in two adjacent metal layers.
2. The test structure according to claim 1, characterized in that, The test structure comprises a first metal layer to a Pth metal layer stacked sequentially; P is a positive integer greater than 1. Each of the first metal layer to the Pth metal layer has a first metal line and a second metal line; Each of the two adjacent metal layers from the first metal layer to the Pth metal layer has a first via and a second via; Wherein, each of the first metal layer to the Pth metal layer includes one first unit; each of the two adjacent metal layers from the first metal layer to the Pth metal layer includes one second unit.
3. The test structure according to claim 1, characterized in that, The test structure comprises a first metal layer to a Qth metal layer stacked sequentially; Q is a positive integer greater than 2. A plurality of first metal lines are located in the first metal layer to the Q-1 metal layer, and a plurality of first vias are located between two adjacent metal layers from the first metal layer to the Q-1 metal layer; A plurality of second metal lines are located in the second metal layer to the Q-th metal layer, and a plurality of second vias are located between two adjacent metal layers from the second metal layer to the Q-th metal layer; Wherein, the first metal layer has one first metal line; the second metal layer to the Q-1 metal layer have two first metal lines; the second metal layer has one second metal line; the third metal layer to the Q-1 metal layer have two second metal lines; all the second metal lines in the second metal layer to the Q-1 metal layer are located between two first metal lines; Wherein, the second metal layer to the Q-1 metal layer each include two of the first unit; the first metal layer and the second metal layer each include one of the second unit; and the two adjacent metal layers from the second metal layer to the Q metal layer each include two of the second unit.
4. The test structure according to claim 1, characterized in that, The test structure comprises a first metal layer, a second metal layer, and a third metal layer stacked sequentially. Multiple first metal lines are located in the first metal layer and the second metal layer, and multiple first vias are located between the first metal layer and the second metal layer; A plurality of second metal lines are located in the second metal layer and the third metal layer, and a plurality of second vias are located between the second metal layer and the third metal layer; Wherein, the second metal layer includes at least one of the first units; the first metal layer and the second metal layer include at least one of the second units; the second metal layer and the third metal layer include at least one of the second units.
5. The test structure according to claim 4, characterized in that, The second metal layer has a plurality of first metal lines and a plurality of second metal lines spaced alternately. Wherein, the second metal layer includes at least three of the first units; the first metal layer and the second metal layer include a first number of the second units; the first number is the number of the plurality of first metal lines in the second metal layer; the second metal layer and the third metal layer include a second number of the second units; the second number is the number of the plurality of second metal lines in the second metal layer.
6. The test structure according to claim 1, characterized in that, The test structure includes a plurality of structural units arranged along a second direction; the second direction intersects with the first direction.
7. The test structure according to claim 6, characterized in that, The test structure includes a plurality of structural units arranged along a third direction; the third direction intersects with the second direction and the first direction, respectively.
8. The test structure according to any one of claims 1 to 7, characterized in that, The first metal wire and the second metal wire of the first unit have a minimum spacing specified by design rules.
9. The test structure according to any one of claims 1 to 7, characterized in that, The characteristic dimension of the width of the first metal wire and / or the second metal wire is the minimum line width or minimum wrapping size specified by the design rules; wherein, the connection between the first metal wire and the first via satisfies the minimum wrapping size of the first metal wire to the first via specified by the design rules.
10. A method for manufacturing a test structure, characterized in that, include: At least one structural unit is formed; wherein the structural unit includes a first connection structure and a second connection structure extending along a first direction and spaced apart; the first connection structure includes a plurality of alternately connected first metal lines and at least one first via; the second connection structure includes a plurality of alternately connected second metal lines and at least one second via; wherein the structural unit includes a first unit and a second unit; the first unit includes first metal lines and second metal lines located in the same metal layer and adjacent to each other; the second unit includes an overlapping portion between first metal lines and second metal lines located in two adjacent metal layers; On the first side of the structural unit, a first pad is formed that is connected to the first connection structure; On the second side of the structural unit, a second pad is formed that is connected to the second connection structure; the first side and the second side are two opposite sides of the structural unit in the first direction.
11. A testing method, characterized in that, The test object of the test method includes the test structure as described in any one of claims 1 to 9, or the test structure obtained by the manufacturing method according to claim 10; the test method includes: A first voltage and a second voltage are applied to the first pad and the second pad of the test structure, respectively; the first voltage is less than the second voltage. Acquire the test current flowing through the first pad or the second pad, and the test voltage between the first pad and the second pad; Based on the test current and the test voltage, the current-voltage characteristic curve of the test structure under the first voltage and the second voltage conditions is obtained; the current-voltage characteristic curve includes the breakdown voltage of the test structure.