Test structures and methods of forming the same

Abstract

A test structure and a method of forming the same, wherein the structure comprises: each conductive structure comprises a first conductive layer and a second conductive layer adjacent to each other and extending along a second direction, and the first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures, the first direction being perpendicular to the second direction; the first conductive plug structure on top of a first connection region or at the bottom of the first connection region, the second conductive plug structure on top of a second connection region or at the bottom of the second connection region, and adjacent first conductive plug structures and second conductive plug structures are respectively on adjacent conductive structures, and the first conductive plug structure or the second conductive plug structure on each conductive structure connects the first conductive layer and the second conductive layer in the conductive structure to each other; a third conductive layer electrically connected to the first conductive plug structure; and a fourth conductive layer electrically connected to the second conductive plug structure, which is conducive to improving the accuracy of the time-dependent breakdown performance test.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a test structure and its formation method. Background Technology

[0002] With the continuous development of integrated circuit manufacturing technology, in order to achieve faster computing speed, larger data storage capacity and more functions, integrated circuit chips are developing towards higher device density and higher integration.

[0003] As the size of Ultra Large Scale Integrated Circuit (ULSI) chips continues to shrink, the size of the gate dielectric layer in semiconductor devices (MOS) is also constantly shrinking to achieve higher performance. When a constant voltage is applied to the device, causing it to accumulate charge, the dielectric layer will break down after a period of time, especially the inter-metal dielectric (IMD) layer. The time elapsed during this breakdown is called the lifetime under that condition, also known as time-dependent dielectric breakdown (TDDB). In the back-end of line (BEOL) process, TDDB performance is one of the key factors in evaluating the stability of the inter-metal dielectric layer and the semiconductor device. To improve device reliability, TDDB performance needs to be considered and tested in the back-end of line process.

[0004] However, the existing test structures for the breakdown performance of metallic dielectric layers over time need further improvement. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a test structure and a method for forming the same, so as to improve the performance of the formed semiconductor structure.

[0006] To solve the above-mentioned technical problems, the present invention provides a test structure, comprising: a substrate; a plurality of conductive structures arranged along a first direction on the substrate, each of the conductive structures including a first connection region and a second connection region arranged along a second direction, wherein the first connection region and the second connection region are respectively located at both ends of the conductive structure, each conductive structure including an adjacent first conductive layer and a second conductive layer extending along the second direction, wherein the first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures, and the first direction is perpendicular to the second direction; a first conductive plug structure located at the top or bottom of the first connection region, a second conductive plug structure located at the top or bottom of the second connection region, wherein adjacent first conductive plug structures and second conductive plug structures are respectively located on adjacent conductive structures, and the first conductive plug structure or the second conductive plug structure on each conductive structure connects the first conductive layer and the second conductive layer in the conductive structure to each other; a third conductive layer electrically connected to the first conductive plug structure; and a fourth conductive layer electrically connected to the second conductive plug structure.

[0007] Optionally, along the first direction, the first conductive layer has opposing first and second sidewalls, and the second conductive layer has opposing third and fourth sidewalls. In each conductive structure, the second sidewall and the third sidewall are adjacent. The distance between the first sidewall and the fourth sidewall along the first direction is greater than the dimension of the first conductive plug structure along the first direction, and the distance between the first sidewall and the fourth sidewall along the first direction is greater than the dimension of the second conductive plug structure along the first direction.

[0008] Optionally, it further includes: a first dielectric layer located on the substrate; a plurality of first openings arranged along a first direction and extending along a second direction located within the first dielectric layer; and the conductive structure located within the first openings.

[0009] Optionally, the first conductive plug structure is located on top of the first connection area, the second conductive plug structure is located on top of the second connection area, and the third conductive layer and the fourth conductive layer are located above the conductive structure.

[0010] Optionally, it further includes: a second dielectric layer located on the surface of the first dielectric layer and the surface of the conductive structure, wherein the first conductive plug structure and the second conductive plug structure are located within the second dielectric layer; a third dielectric layer located on the second dielectric layer; and the third conductive layer and the fourth conductive layer located within the third dielectric layer.

[0011] Optionally, the first conductive plug structure is located at the bottom of the first connection area, the second conductive plug structure is located at the bottom of the second connection area, and the third conductive layer and the fourth conductive layer are located below the conductive structure.

[0012] Optionally, it further includes: a second dielectric layer located between the first dielectric layer and the substrate, wherein the third conductive layer and the fourth conductive layer are located within the second dielectric layer; and a third dielectric layer located between the second dielectric layer and the first dielectric layer, wherein the first conductive plug structure and the second conductive plug structure are located within the third dielectric layer.

[0013] Optionally, the first conductive plug structure includes a plurality of first conductive plugs arranged along a second direction; the second conductive plug structure includes a plurality of second conductive plugs arranged along a second direction.

[0014] Optionally, the substrate includes a base and a device structure located on the base, wherein the conductive structure is electrically connected to the device structure.

[0015] Accordingly, the present invention also provides a method for forming a semiconductor structure, comprising: providing a substrate; forming a plurality of conductive structures arranged along a first direction on the substrate, wherein each of the plurality of conductive structures includes a first connection region and a second connection region arranged along a second direction, and the first connection region and the second connection region are respectively located at both ends of the conductive structure, each conductive structure includes an adjacent first conductive layer and a second conductive layer extending along the second direction, and the first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures, the first direction being perpendicular to the second direction; forming a first conductive plug structure and a second conductive plug structure, wherein the first conductive plug structure is located at the top or bottom of the first connection region, the second conductive plug structure is located at the top or bottom of the second connection region, and adjacent first conductive plug structures and second conductive plug structures are respectively located on adjacent conductive structures, and the first conductive plug structure or the second conductive plug structure on each conductive structure connects the first conductive layer and the second conductive layer in the conductive structure to each other; forming a third conductive layer electrically connected to the first conductive plug structure; and forming a fourth conductive layer electrically connected to the second conductive plug structure.

[0016] Optionally, the method for forming the conductive structure includes: forming a first dielectric layer on the substrate; forming a plurality of first openings arranged along a first direction and extending along a second direction in the first dielectric layer; and forming a first conductive layer and a second conductive layer in the first openings.

[0017] Optionally, after forming the first dielectric layer, a second dielectric layer is formed on the surface of the first dielectric layer and the surface of the conductive structure; the first conductive plug structure and the second conductive plug structure are formed in the second dielectric layer; after forming the first conductive plug structure and the second conductive plug structure, a third dielectric layer is formed on the second dielectric layer; and the third conductive layer and the fourth conductive layer are formed in the third dielectric layer.

[0018] Optionally, before forming the first dielectric layer, a second dielectric layer and the third conductive layer and the fourth conductive layer located within the second dielectric layer are formed on the surface of the substrate; after forming the second dielectric layer and before forming the first dielectric layer, a third dielectric layer is formed on the second dielectric layer; and the first conductive plug structure and the second conductive plug structure are formed within the third dielectric layer.

[0019] Accordingly, the technical solution of the present invention also provides a method for operating a test structure, comprising: providing a test structure, the test structure comprising: a substrate; a plurality of conductive structures arranged along a first direction on the substrate, each of the plurality of conductive structures comprising a first connection region and a second connection region arranged along a second direction, wherein the first connection region and the second connection region are respectively located at both ends of the conductive structure, each conductive structure comprising an adjacent first conductive layer and a second conductive layer extending along the second direction, wherein the first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures, and the first direction is perpendicular to the second direction; located at the top of the first connection region or The first conductive plug structure at the bottom of the first connection area, the second conductive plug structure at the top or bottom of the second connection area, and adjacent first and second conductive plug structures are respectively located on adjacent conductive structures, and the first or second conductive plug structures on each conductive structure connect the first and second conductive layers in the conductive structure to each other; a third conductive layer electrically connected to the first conductive plug structure; a fourth conductive layer electrically connected to the second conductive plug structure; a first bias voltage applied to the third conductive layer; and a second bias voltage applied to the fourth conductive layer, wherein the first bias voltage and the second bias voltage are different.

[0020] Optionally, the third conductive layer is connected to the stress voltage, and the fourth conductive layer is grounded.

[0021] Optionally, the fourth conductive layer is connected to the stress voltage, and the third conductive layer is grounded.

[0022] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0023] In the method for forming the test structure provided by the present invention, a third conductive layer electrically connected to a first conductive plug structure is formed, and a fourth conductive layer electrically connected to a second conductive plug structure is formed. When the formed test structure is used, a test voltage is applied to the third and fourth conductive layers respectively to test the breakdown performance of the dielectric layer between the first and second conductive layers. The first or second conductive plug structure interconnects the first and second conductive layers in the conductive structure. The distance between the first (or second) conductive plug structure and the second conductive layer (or first) of an adjacent conductive structure is greater than the distance between the first conductive layer of the conductive structure and the second conductive layer of the adjacent conductive structure. This reduces the likelihood that the dielectric layer between the first (or second) conductive plug structure and the adjacent second conductive layer (or first conductive layer) will break down before the dielectric layer between the first and second conductive layers, thus improving the accuracy of the breakdown performance test over time.

[0024] In the test structure provided by the present invention, when using the test structure, test voltages are applied to the third conductive layer and the fourth conductive layer respectively to test the breakdown performance of the dielectric layer between the first conductive layer and the second conductive layer. The first conductive plug structure or the second conductive plug structure connects the first conductive layer and the second conductive layer in the conductive structure. The distance between the first conductive plug structure (or the second conductive plug structure) and the second conductive layer (or the first conductive layer) of the adjacent conductive structure is greater than the distance between the first conductive layer of the conductive structure and the second conductive layer of the adjacent conductive structure. This reduces the possibility that the dielectric layer between the first conductive plug structure (or the second conductive plug structure) and the adjacent second conductive layer (or the first conductive layer) will break down before the dielectric layer between the first conductive layer and the second conductive layer, thus improving the accuracy of the breakdown performance test over time. Attached Figure Description

[0025] Figures 1 to 3 This is a schematic diagram of a test structure;

[0026] Figures 4 to 6 This is a schematic diagram of another test structure;

[0027] Figures 7 to 13 This is a schematic diagram of the steps in the method for forming a test structure according to an embodiment of the present invention;

[0028] Figures 14 to 16 This is a schematic diagram of the test structure according to another embodiment of the present invention. Detailed Implementation

[0029] As described in the background section, the existing test structures for the breakdown performance of metal dielectric layers over time need further improvement. This paper will now illustrate and analyze this with reference to a semiconductor structure.

[0030] It should be noted that the terms "surface" and "on" in this specification are used to describe the relative spatial position and are not limited to whether there is direct contact.

[0031] Figures 1 to 3 This is a schematic diagram of a test structure.

[0032] Please refer to Figures 1 to 3 , Figure 1 yes Figure 2 and Figure 3 A top-view structural diagram (substrate omitted). Figure 2 yes Figure 1 A cross-sectional view of the structure along the central axis D1D2. Figure 3 yes Figure 1 A cross-sectional view along E1E2 shows the semiconductor structure, which includes: a substrate; a first conductive layer on the substrate, the first conductive layer comprising a first region I, a second region II, and a third region III arranged along a first direction X, the first region I and the third region III being located at opposite ends of the first conductive layer; the first conductive layer comprising multiple first electrodes 101 and multiple second electrodes 102, the multiple first electrodes 101 and the multiple second electrodes 102 being parallel to the first direction X and arranged along a second direction Y, the first direction X being perpendicular to the second direction Y; the first electrodes 101 being located in the second region II and extending to the first region I; and the second electrodes 102 being located in the second region II and extending to the first region I. The third region III, each of the second electrodes 102 in the second region II is located between two adjacent first electrodes 102; a second conductive layer 103 is located on the first region I, the second conductive layer 103 is parallel to the second direction Y; a plurality of first conductive plugs 105 are located on the first region I, the second conductive layer 103 is electrically connected to a plurality of first electrodes 101 through the first conductive plugs 105; a third conductive layer 104 is located on the third region III, the third conductive layer 104 is parallel to the second direction Y; a plurality of second conductive plugs 106 are located on the third region III, the third conductive layer 104 is electrically connected to a plurality of second electrodes 102 through the second conductive plugs 106.

[0033] The above structure serves as a test structure for time-dependent breakdown performance, used to test the performance of the dielectric layer between the first electrode 101 and the second electrode 102. The line ends on one side of the first electrode 101 and the second electrode 102 are located in the first region I and the second region II, respectively, while the line ends on the other side are located in the second region II and the third region II, respectively. That is, the line ends of the first electrode 101 and the second electrode 102 are not aligned. The first electrode 101 and the second electrode 102 need to be formed through two photolithography steps: first, the first electrode 101 (or the second electrode 102) is formed, and then the second electrode 102 (or the first electrode 101) is formed using a second photolithography step. However, as integrated circuit chips develop towards higher device densities and feature sizes continue to shrink, etching to form even smaller, finer patterns on top of forming the first electrode 101 (or the second electrode 102) presents a significant challenge to existing photolithography technology.

[0034] To meet advanced process requirements, in another test structure, the line ends of the first electrode 101 and the second electrode 102 are aligned. The first electrode 101 and the second electrode 102 can be formed in one step using self-aligned double patterning (SADP) technology. Please refer to the test structure described above. Figures 4 to 6 .

[0035] Figures 4 to 6 This is a schematic diagram of another test structure.

[0036] Please refer to Figures 4 to 6 , Figure 4 yes Figure 5 and Figure 6 A top-view structural diagram (substrate omitted). Figure 5 yes Figure 4 A schematic diagram of the cross-sectional structure along the central direction. Figure 6 yes Figure 4A cross-sectional view of the semiconductor structure along the mid-direction shows that the semiconductor structure includes: a substrate; a first conductive layer on the substrate, the first conductive layer including multiple first electrodes 201 and multiple second electrodes 202, the multiple first electrodes 201 and multiple second electrodes 202 being parallel to a first direction X and arranged along a second direction Y, the first direction X being perpendicular to the second direction Y, each second electrode 202 being located between two adjacent first electrodes 202 and along the first direction X, the first conductive layer having opposing first ends I and second ends II at both ends, and the ends of the first electrodes 201 and the second electrodes 202 being aligned respectively; A second conductive layer 203 is located on the first end I of the first electrode 201, and the second conductive layer 203 is parallel to the second direction Y; a plurality of first conductive plugs 205 are located on the second end II, and the second conductive layer 203 is electrically connected to the plurality of first electrodes 201 through the first conductive plugs 205; a third conductive layer 204 is located on the second end II of the second electrode 202, and the third conductive layer 204 is parallel to the second direction Y; a plurality of second conductive plugs 206 are located on the second end II, and the third conductive layer 204 is electrically connected to the plurality of second electrodes 202 through the second conductive plugs 206.

[0037] However, the above structure encountered new challenges when used as a test structure for breakdown performance over time. For example... Figure 5 (or Figure 6 In the area indicated by the dashed line, due to alignment issues during the photolithography process of forming the first conductive plug 205 (or the second conductive plug 206) or because the width of the first conductive plug 205 (or the second conductive plug 206) is greater than the width of the first electrode 201 (or the second electrode 202), the distance between the first conductive plug 205 (or the second conductive plug 206) and the second electrode 202 (or the first electrode 201) is smaller than the distance between the first electrode 201 and the second electrode 202. When testing the breakdown performance over time, the test voltage is applied to both the first electrode 201 and the second electrode 202, which can easily lead to the dielectric layer between the first conductive plug 205 (or the second conductive plug 206) and the second electrode 202 (or the first electrode 201) breaking down before the dielectric layer between the first electrode 201 and the second electrode 202. This makes it impossible to accurately measure the breakdown performance of the dielectric layer between the first electrode 201 and the second electrode 202 over time.

[0038] To address the aforementioned problems, the present invention provides a method for forming a test structure, in which a third conductive layer electrically connected to a first conductive plug structure is formed, and a fourth conductive layer electrically connected to a second conductive plug structure is formed. In use, a test voltage is applied to the third and fourth conductive layers respectively to test the breakdown performance of the dielectric layer between the first and second conductive layers. The first or second conductive plug structure interconnects the first and second conductive layers in the conductive structure. The distance between the first (or second) conductive plug structure and the second conductive layer (or first) of an adjacent conductive structure is greater than the distance between the first conductive layer of one conductive structure and the second conductive layer of an adjacent conductive structure. This reduces the likelihood that the dielectric layer between the first (or second) conductive plug structure and the adjacent second conductive layer (or first conductive layer) will break down before the dielectric layer between the first and second conductive layers, thus improving the accuracy of the breakdown performance test over time.

[0039] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Figures 7 to 13 This is a schematic diagram of the steps in the method for forming a test structure according to an embodiment of the present invention.

[0041] Please refer to Figure 7 Substrate 300 is provided.

[0042] In this embodiment, the substrate 300 further includes a substrate (not shown in the figure) and a device structure (not shown in the figure) located on the substrate. The device structure includes one or more combinations of transistors, diodes, triodes, capacitors, inductors, and conductive structures.

[0043] Subsequently, a plurality of conductive structures arranged along a first direction are formed on the substrate 300. The conductive structures are electrically connected to the device structure.

[0044] Please refer to Figure 8 and Figure 9 , Figure 8 for Figure 9 The top view of the first dielectric layer is omitted. Figure 9 for Figure 8A cross-sectional view along the O1-O2 direction is shown. A plurality of conductive structures 301 arranged along the first direction X are formed on the substrate 300. Each of the conductive structures 301 includes a first connection region I and a second connection region II arranged along the second direction Y. The first connection region I and the second connection region II are respectively located at both ends of the conductive structure 301. Each conductive structure 301 includes an adjacent first conductive layer 301a and a second conductive layer 301b extending along the second direction Y. The first conductive layer 301a in each conductive structure 301 is adjacent to the second conductive layer 301b in the adjacent group of conductive structures 301. The first direction X is perpendicular to the second direction Y.

[0045] In this embodiment, the method for forming the conductive structure 301 includes: forming a first dielectric layer 302 on the substrate 300; forming a plurality of first openings (not shown in the figure) arranged along a first direction X and extending along a second direction Y in the first dielectric layer 302; and forming a first conductive layer 301a and a second conductive layer 301b in the first openings. Specifically, the method for forming the conductive structure 301 further includes: forming a first conductive material layer in the first openings and on the surface of the first dielectric layer 302; planarizing the first conductive material layer until the surface of the first dielectric layer 302 is exposed, thereby forming the first conductive layer 301a and the second conductive layer 301b.

[0046] The materials of the first conductive layer 301a and the second conductive layer 301b include metals, such as aluminum or copper. In this embodiment, the materials of the first conductive layer 301a and the second conductive layer 301b are copper.

[0047] Subsequently, in this embodiment, after forming the first dielectric layer, a second dielectric layer is formed on the surface of the first dielectric layer and the surface of the conductive structure; the first conductive plug structure and the second conductive plug structure are formed in the second dielectric layer; after forming the first conductive plug structure and the second conductive plug structure, a third dielectric layer is formed on the second dielectric layer; and the third conductive layer and the fourth conductive layer are formed in the third dielectric layer.

[0048] In another embodiment, before forming the first dielectric layer, a second dielectric layer and the third conductive layer and the fourth conductive layer located within the second dielectric layer are formed on the surface of the substrate; after forming the second dielectric layer and before forming the first dielectric layer, a third dielectric layer is formed on the second dielectric layer; and the first conductive plug structure and the second conductive plug structure are formed within the third dielectric layer.

[0049] Please refer to Figure 10 and Figure 11 , Figure 10 yes Figure 11The top view of the second dielectric layer is omitted. Figure 11 yes Figure 10 A cross-sectional view along the O1O2 direction shows a first conductive plug structure 303 and a second conductive plug structure 304. The first conductive plug structure 303 is located at the top or bottom of the first connection area I, and the second conductive plug structure 304 is located at the top or bottom of the second connection area II. Adjacent first conductive plug structures 303 and second conductive plug structures 304 are located on adjacent conductive structures 301, and the first conductive plug structure 303 or the second conductive plug structure 304 on each conductive structure 301 connects the first conductive layer 301a and the second conductive layer 301b in the conductive structure 301 to each other.

[0050] Along the first direction X, the first conductive layer 301a has opposing first sidewalls (not shown) and second sidewalls (not shown), and the second conductive layer 301b has opposing third sidewalls (not shown) and fourth sidewalls (not shown). In each conductive structure 301, the second sidewall and the third sidewall are adjacent. The distance m between the first sidewall and the fourth sidewall along the first direction X is greater than the dimension n of the first conductive plug structure 303 along the first direction X. The distance m between the first sidewall and the fourth sidewall along the first direction X is greater than the dimension z of the second conductive plug structure 304 along the first direction X.

[0051] Specifically, in this embodiment, after the first dielectric layer 302 is formed, a second dielectric layer 305 is formed on the surface of the first dielectric layer 302 and the surface of the conductive structure 301; the first conductive plug structure 303 and the second conductive plug structure 304 are formed in the second dielectric layer 305.

[0052] In this embodiment, after forming the conductive structure 301, a first conductive plug structure 303 and a second conductive plug structure 304 are formed. The first conductive plug structure 303 is located at the top of the first connection region I, and the second conductive plug structure 304 is located at the top of the second connection region II. In another embodiment, after forming the second dielectric layer and before forming the first dielectric layer, a third dielectric layer is formed on the second dielectric layer; the first conductive plug structure and the second conductive plug structure are formed within the third dielectric layer. The first conductive plug structure is located at the bottom of the first connection region, and the second conductive plug structure is located at the bottom of the second connection region.

[0053] The method for forming the first conductive plug structure 303 and the second conductive plug structure 304 includes: forming a plurality of plug holes (not shown in the figure) in the second dielectric layer 305, wherein the plug holes expose a portion of the first conductive layer 301a and a portion of the second conductive layer 301b; forming a second conductive material layer in the plug holes and on the surface of the second dielectric layer 305; planarizing the second conductive material layer until the surface of the second dielectric layer 305 is exposed; and forming the first conductive plug structure 303 and the second conductive plug structure 304 in the plug holes.

[0054] The first conductive plug structure 303 includes a plurality of first conductive plugs (not shown in the figure), which are arranged along the second direction Y; the second conductive plug structure 304 includes a plurality of second conductive plugs (not shown in the figure), which are arranged along the second direction Y.

[0055] In this embodiment, the number of first conductive plugs connected to one of the conductive structures 301 is three. In other embodiments, the number of first conductive plugs connected to one of the conductive structures 301 can be adjusted according to the actual process requirements.

[0056] In this embodiment, the number of second conductive plugs connected to one of the conductive structures 301 is three. In other embodiments, the number of first conductive plugs connected to one of the conductive structures 301 can be adjusted according to the actual process requirements.

[0057] The first and second conductive plugs are made of metal, including tungsten, cobalt, or copper. In this embodiment, the first and second conductive plugs are made of tungsten.

[0058] Please refer to Figure 12 and Figure 13 , Figure 12 yes Figure 13 The top view of the third dielectric layer is omitted. Figure 13 yes Figure 12 A cross-sectional structural diagram along the O1O2 direction shows a third conductive layer 306 electrically connected to the first conductive plug structure 303, and a fourth conductive layer 307 electrically connected to the second conductive plug structure 304.

[0059] When the test structure is used, the test voltage is applied to the third conductive layer 306 and the fourth conductive layer 307 respectively to test the breakdown performance of the dielectric layer between the first conductive layer 301a and the second conductive layer 301b. The first conductive plug structure 303 or the second conductive plug structure 304 connects the first conductive layer 301a and the second conductive layer 301b in the conductive structure 301. The distance h between the first conductive plug structure 303 (or the second conductive plug structure 304) and the second conductive layer 301b (or the first conductive layer 301a) of the adjacent conductive structure 301 is greater than the distance l between the first conductive layer 301a and the second conductive layer 301b of the adjacent conductive structure 301. This reduces the possibility that the dielectric layer between the first conductive plug structure 303 (or the second conductive plug structure 304) and the adjacent second conductive layer 301b (or the first conductive layer 301a) will break down before the dielectric layer between the first conductive layer 301a and the second conductive layer 301b. Therefore, the accuracy of the breakdown performance test over time can be improved.

[0060] In this embodiment, after the first conductive plug structure 303 and the second conductive plug structure 304 are formed, a third dielectric layer 308 is formed on the second dielectric layer 305; and the third conductive layer 306 and the fourth conductive layer 307 are formed in the third dielectric layer 308.

[0061] The method for forming the third conductive layer 306 and the fourth conductive layer 307 includes: forming a second opening (not shown in the figure) in the third dielectric layer 308, the second opening exposing the first conductive plug structure 303 and the second conductive plug structure 304; forming a third conductive material layer on the second opening and the surface of the third dielectric layer 308; planarizing the third conductive material layer until the surface of the third dielectric layer 308 is exposed, thereby forming the third conductive layer 306 and the fourth conductive layer 307.

[0062] In another embodiment, the third conductive layer and the fourth conductive layer are located below the conductive structure. The conductive structure is electrically connected to the third conductive layer by the first conductive plug structure at the bottom of the first connection area, and the conductive structure is electrically connected to the fourth conductive layer by the first conductive plug structure at the bottom of the second connection area. Similarly, this can reduce the possibility that the dielectric layer between the first conductive plug structure (or the second conductive plug structure) and the adjacent second conductive layer (or the first conductive layer) will break down before the dielectric layer between the first conductive layer and the second conductive layer, thereby improving the accuracy of the breakdown performance test over time.

[0063] Accordingly, one embodiment of the present invention also provides a semiconductor structure formed using the above method. Please refer to [the original text]. Figure 12 and Figure 13 The system includes: a substrate 300; a plurality of conductive structures 301 arranged along a first direction X on the substrate 300, each of the conductive structures 301 including a first connection region I and a second connection region II arranged along a second direction Y, wherein the first connection region I and the second connection region II are respectively located at both ends of the conductive structure 301, each conductive structure 301 including an adjacent first conductive layer 301a and a second conductive layer 301b extending along the second direction Y, wherein the first conductive layer 301a in each conductive structure 301 is adjacent to the second conductive layer 301b in an adjacent group of conductive structures 301, and the first direction X is perpendicular to the second direction Y; a first conductive plug structure 303 located at the top or bottom of the first connection region I, and a second conductive plug structure 304 located at the top or bottom of the second connection region II, wherein adjacent first conductive plug structures 303 (e.g., Figure 10 (as shown) and the second conductive plug structure 304 (as shown) Figure 10 (As shown) are located on adjacent conductive structures 301, and the first conductive plug structure 303 or the second conductive plug structure 304 on each conductive structure 301 connects the first conductive layer 301a and the second conductive layer 301b in the conductive structure 301 to each other; the third conductive layer 306 is electrically connected to the first conductive plug structure 303; and the fourth conductive layer 307 is electrically connected to the second conductive plug structure 304.

[0064] When using the test structure, test voltages are applied to the third conductive layer 306 and the fourth conductive layer 307 respectively to test the breakdown performance of the dielectric layer between the first conductive layer 301a and the second conductive layer 301b. The first conductive plug structure 303 or the second conductive plug structure 304 connects the first conductive layer 301a and the second conductive layer 301b in the conductive structure 301. The distance h between the first conductive plug structure 303 (or the second conductive plug structure 304) and the second conductive layer 301b (or the first conductive layer 301a) of the adjacent conductive structure 301 is greater than the distance l between the first conductive layer 301 of the conductive structure 301 and the second conductive layer 301b of the adjacent conductive structure 301. This reduces the possibility that the dielectric layer between the first conductive plug structure 303 (or the second conductive plug structure 304) and the adjacent second conductive layer 301b (or the first conductive layer 301a) will break down before the dielectric layer between the first conductive layer 301a and the second conductive layer 301b. Therefore, the accuracy of the breakdown performance test over time can be improved.

[0065] Along the first direction X, the first conductive layer 301a has opposing first sidewalls (not shown) and second sidewalls (not shown), and the second conductive layer 301b has opposing third sidewalls (not shown) and fourth sidewalls (not shown). In each conductive structure 301, the second sidewall and the third sidewall are adjacent. The distance m between the first sidewall and the fourth sidewall along the first direction X is greater than the dimension n of the first conductive plug structure 303 along the first direction X. The distance m between the first sidewall and the fourth sidewall along the first direction X is greater than the dimension z of the second conductive plug structure 304 along the first direction X.

[0066] The test structure further includes: a first dielectric layer 302 located on the substrate 300; a plurality of first openings arranged along a first direction X and extending along a second direction Y within the first dielectric layer 302; and the conductive structure 301 located within the first openings.

[0067] In this embodiment, the first conductive plug structure 303 is located on top of the first connection area I, the second conductive plug structure 304 is located on top of the second connection area II, and the third conductive layer 306 and the fourth conductive layer 307 are located above the conductive structure 301.

[0068] The test structure further includes: a second dielectric layer 305 located on the surface of the first dielectric layer 302 and the surface of the conductive structure 301, wherein the first conductive plug structure 303 and the second conductive plug structure 304 are located within the second dielectric layer 305; a third dielectric layer 308 located on the second dielectric layer 305; and the third conductive layer 306 and the fourth conductive layer 307 located within the third dielectric layer 308.

[0069] In another embodiment, the first conductive plug structure is located at the bottom of the first connection area, the second conductive plug structure is located at the bottom of the second connection area, and the third conductive layer and the fourth conductive layer are located below the conductive structure.

[0070] In another embodiment, the test structure further includes: a second dielectric layer located between the first dielectric layer and the substrate, wherein the third conductive layer and the fourth conductive layer are located within the second dielectric layer; and a third dielectric layer located between the second dielectric layer and the first dielectric layer, wherein the first conductive plug structure and the second conductive plug structure are located within the third dielectric layer.

[0071] The first conductive plug structure 303 includes a plurality of first conductive plugs, which are arranged along the second direction Y; the second conductive plug structure 304 includes a plurality of second conductive plugs, which are arranged along the second direction Y.

[0072] Accordingly, one embodiment of the present invention also provides a method for operating a test structure, including: providing a test structure, the test structure of which is referred to in [reference needed]. Figures 12 to 13 The system includes: a substrate 300; a plurality of conductive structures 301 arranged along a first direction X on the substrate 300, each of the conductive structures 301 including a first connection region I and a second connection region II arranged along a second direction Y, wherein the first connection region I and the second connection region II are respectively located at both ends of the conductive structure 301, each conductive structure 301 including an adjacent first conductive layer 301a and a second conductive layer 301b extending along the second direction Y, wherein the first conductive layer 301a in each conductive structure 301 is adjacent to the second conductive layer 301b in an adjacent group of conductive structures 301, and the first direction X is perpendicular to the second direction Y; a first conductive plug structure 303 located at the top or bottom of the first connection region I, and a second conductive plug structure 304 located at the top or bottom of the second connection region II, wherein adjacent first conductive plug structures 303 (e.g., Figure 10 (as shown) and the second conductive plug structure 304 (as shown) Figure 10 (As shown) are located on adjacent conductive structures 301, and the first conductive plug structure 303 or the second conductive plug structure 304 on each conductive structure 301 connects the first conductive layer 301a and the second conductive layer 301b in the conductive structure 301 to each other; a third conductive layer 306 is electrically connected to the first conductive plug structure 303; a fourth conductive layer 307 is electrically connected to the second conductive plug structure 304; a first bias voltage is applied to the third conductive layer 306; a second bias voltage is applied to the fourth conductive layer 307, wherein the first bias voltage and the second bias voltage are different.

[0073] In this embodiment, the third conductive layer 306 is connected to the stress voltage, and the fourth conductive layer 307 is grounded. In other embodiments, the fourth conductive layer is connected to the stress voltage, and the third conductive layer is grounded.

[0074] Figures 14 to 16 This is a schematic diagram of the test structure according to another embodiment of the present invention.

[0075] Please refer to Figures 14 to 16 , Figure 14 for Figure 15 A top-view structural diagram. Figure 15 for Figure 14 A schematic diagram of the cross-sectional structure along the P1P2 direction. Figure 16 for Figure 14A cross-sectional structural diagram along the E3E4 direction includes: a substrate 400; and a plurality of conductive structures 401 arranged along a first direction X on the substrate 400. Each conductive structure 401 includes a first connection region I and a second connection region II arranged along a second direction Y, with the first connection region I and the second connection region II located at opposite ends of the conductive structure 401. Each conductive structure 401 includes an adjacent first conductive layer 401a and a second conductive layer 401b extending along the second direction Y. The first conductive layer 401a in each conductive structure 401 is adjacent to the second conductive layer 401b in an adjacent group of conductive structures 401. The first direction X and the second direction Y are... The second direction Y is perpendicular; the first conductive plug structure 403 is located at the bottom of the first connection area I, the second conductive plug structure 404 is located at the bottom of the second connection area II, and adjacent first conductive plug structures 403 and second conductive plug structures 404 are respectively located on adjacent conductive structures 401, and the first conductive plug structure 403 or the second conductive plug structure 404 on each conductive structure 401 connects the first conductive layer 401a and the second conductive layer 401b in the conductive structure 401 to each other; the third conductive layer 406 is electrically connected to the first conductive plug structure 403; and the fourth conductive layer 407 is electrically connected to the second conductive plug structure 404.

[0076] The test structure described in this embodiment and Figures 12 to 13 The difference in the test structures described is as follows:

[0077] In this embodiment, the first conductive plug structure 401 is located at the bottom of the first connection area I, and the second conductive plug structure 404 is located at the bottom of the second connection area II; the third conductive layer 406 and the fourth conductive layer 407 are located below the conductive structure 401.

[0078] The test structure further includes: a first dielectric layer 402 located on the substrate 400; a plurality of first openings (not shown in the figure) arranged along a first direction X and extending along a second direction Y within the first dielectric layer 402; and the conductive structure 401 located within the first openings.

[0079] In this embodiment, the first conductive plug structure 403 is located at the bottom of the first connection area I, and the second conductive plug structure 404 is located at the bottom of the second connection area II; the third conductive layer 406 and the fourth conductive layer 407 are located below the conductive structure 401.

[0080] In this embodiment, the test structure further includes: a second dielectric layer 408 located between the first dielectric layer 402 and the substrate 400, wherein the third conductive layer 406 and the fourth conductive layer 407 are located within the second dielectric layer 408; and a third dielectric layer 405 located between the second dielectric layer 408 and the first dielectric layer 402, wherein the first conductive plug structure 403 and the second conductive plug structure 404 are located within the third dielectric layer 405.

[0081] The first conductive plug structure 403 includes a plurality of first conductive plugs (not shown in the figure), which are arranged along a second direction; the second conductive plug structure 403 includes a plurality of second conductive plugs, which are arranged along a second direction.

[0082] Accordingly, another embodiment of the present invention also provides a method for forming a test structure, the formation process of which is described in reference to... Figures 7 to 13 The details of that description will not be repeated here.

[0083] Accordingly, another embodiment of the present invention also provides a method for operating the test structure, the method of operating the test structure is described above and will not be repeated here.

[0084] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A test structure, characterized in that, include: Substrate; A plurality of conductive structures arranged along a first direction are located on the substrate. Each of the conductive structures includes a first connection region and a second connection region arranged along a second direction. The first connection region and the second connection region are respectively located at both ends of the conductive structure. Each conductive structure includes an adjacent first conductive layer and a second conductive layer that extend along the second direction. The first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures. The first direction is perpendicular to the second direction, and the first direction and the second direction are parallel to the surface of the substrate. A first conductive plug structure is located at the top or bottom of the first connection area, and a second conductive plug structure is located at the top or bottom of the second connection area. Adjacent first and second conductive plug structures are located on adjacent conductive structures, and the first or second conductive plug structure on each conductive structure connects the first and second conductive layers in the conductive structure to each other. The distance between the first conductive plug structure connecting the conductive structure and the second conductive layer of the adjacent conductive structure is greater than the distance between the first conductive layer of the conductive structure and the second conductive layer of the adjacent conductive structure. A third conductive layer electrically connected to the first conductive plug structure; A fourth conductive layer electrically connected to the second conductive plug structure.

2. The test structure as described in claim 1, characterized in that, Along the first direction, the first conductive layer has opposing first and second sidewalls, and the second conductive layer has opposing third and fourth sidewalls. In each conductive structure, the second sidewall and the third sidewall are adjacent. The distance between the first sidewall and the fourth sidewall along the first direction is greater than the dimension of the first conductive plug structure along the first direction. The distance between the first sidewall and the fourth sidewall along the first direction is greater than the dimension of the second conductive plug structure along the first direction.

3. The test structure as described in claim 1, characterized in that, Also includes: The first dielectric layer is located on the substrate; A plurality of first openings located within the first dielectric layer, arranged along a first direction and extending along a second direction; The conductive structure is located within the first opening.

4. The test structure as described in claim 3, characterized in that, The first conductive plug structure is located on top of the first connection area, the second conductive plug structure is located on top of the second connection area, and the third conductive layer and the fourth conductive layer are located above the conductive structure.

5. The test structure as described in claim 4, characterized in that, Also includes: A second dielectric layer is located on the surface of the first dielectric layer and the surface of the conductive structure, and the first conductive plug structure and the second conductive plug structure are located within the second dielectric layer; A third dielectric layer is located on the second dielectric layer; the third conductive layer and the fourth conductive layer are located within the third dielectric layer.

6. The test structure as described in claim 3, characterized in that, The first conductive plug structure is located at the bottom of the first connection area, the second conductive plug structure is located at the bottom of the second connection area, and the third conductive layer and the fourth conductive layer are located below the conductive structure.

7. The test structure as described in claim 6, characterized in that, Also includes: A second dielectric layer is located between the first dielectric layer and the substrate, and the third conductive layer and the fourth conductive layer are located within the second dielectric layer; A third dielectric layer is located between the second dielectric layer and the first dielectric layer, and the first conductive plug structure and the second conductive plug structure are located within the third dielectric layer.

8. The test structure as described in claim 1, characterized in that, The first conductive plug structure includes a plurality of first conductive plugs arranged along a second direction; the second conductive plug structure includes a plurality of second conductive plugs arranged along a second direction.

9. The test structure as described in claim 1, characterized in that, The substrate includes a base and a device structure located on the base; the conductive structure is electrically connected to the device structure.

10. A method for forming a test structure, characterized in that, include: Provide substrate; A plurality of conductive structures are formed on a substrate along a first direction. Each of the conductive structures includes a first connection region and a second connection region arranged along a second direction. The first connection region and the second connection region are respectively located at both ends of the conductive structure. Each conductive structure includes an adjacent first conductive layer and a second conductive layer that extend along the second direction. The first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures. The first direction is perpendicular to the second direction, and the first direction and the second direction are parallel to the surface of the substrate. A first conductive plug structure and a second conductive plug structure are formed. The first conductive plug structure is located at the top or bottom of the first connection area, and the second conductive plug structure is located at the top or bottom of the second connection area. Adjacent first conductive plug structures and second conductive plug structures are located on adjacent conductive structures. The first conductive plug structure or the second conductive plug structure on each conductive structure connects the first conductive layer and the second conductive layer in the conductive structure to each other. The distance between the first conductive plug structure connecting the conductive structure and the second conductive layer of the adjacent conductive structure is greater than the distance between the first conductive layer of the conductive structure and the second conductive layer of the adjacent conductive structure. A third conductive layer is formed that is electrically connected to the first conductive plug structure; A fourth conductive layer is formed that is electrically connected to the second conductive plug structure.

11. The method for forming the test structure as described in claim 10, characterized in that, The method for forming the conductive structure includes: forming a first dielectric layer on the substrate; forming a plurality of first openings arranged along a first direction and extending along a second direction in the first dielectric layer; and forming a first conductive layer and a second conductive layer in the first openings.

12. The method for forming the test structure as described in claim 11, characterized in that, After the first dielectric layer is formed, a second dielectric layer is formed on the surface of the first dielectric layer and the surface of the conductive structure; the first conductive plug structure and the second conductive plug structure are formed in the second dielectric layer. After forming the first conductive plug structure and the second conductive plug structure, a third dielectric layer is formed on the second dielectric layer; the third conductive layer and the fourth conductive layer are formed within the third dielectric layer.

13. The method for forming the test structure as described in claim 11, characterized in that, Before forming the first dielectric layer, a second dielectric layer and a third conductive layer and a fourth conductive layer located within the second dielectric layer are formed on the surface of the substrate; after forming the second dielectric layer and before forming the first dielectric layer, a third dielectric layer is formed on the second dielectric layer; and the first conductive plug structure and the second conductive plug structure are formed within the third dielectric layer.

14. A method for testing a structure, characterized in that, include: A test structure is provided, comprising: a substrate; a plurality of conductive structures arranged along a first direction on the substrate, each of the conductive structures including a first connection region and a second connection region arranged along a second direction, wherein the first connection region and the second connection region are respectively located at both ends of the conductive structure, each conductive structure including an adjacent first conductive layer and a second conductive layer extending along the second direction, wherein the first conductive layer in each conductive structure is adjacent to the second conductive layer in an adjacent group of conductive structures, the first direction is perpendicular to the second direction, and the first direction and the second direction are parallel to the surface of the substrate; a first conductive layer located at the top or bottom of the first connection region. An electrical plug structure includes a second conductive plug structure located at the top or bottom of the second connection area, with adjacent first and second conductive plug structures located on adjacent conductive structures. The first or second conductive plug structures on each conductive structure connect the first and second conductive layers of the conductive structure to each other. The distance between the first conductive plug structure connecting the conductive structure and the second conductive layer of the adjacent conductive structure is greater than the distance between the first conductive layer of the conductive structure and the second conductive layer of the adjacent conductive structure. A third conductive layer is electrically connected to the first conductive plug structure. A fourth conductive layer is electrically connected to the second conductive plug structure. A first bias voltage is applied to the third conductive layer; A second bias voltage is applied to the fourth conductive layer, and the first bias voltage is different from the second bias voltage.

15. The method of operating the test structure as described in claim 14, characterized in that, The third conductive layer is connected to the stress voltage, and the fourth conductive layer is grounded.

16. The method of operating the test structure as described in claim 14, characterized in that, The fourth conductive layer is connected to the stress voltage, and the third conductive layer is grounded.

Images