Semiconductor test structure and method for testing alignment offset between metal layers

Abstract

The invention provides a semiconductor test structure and a method for testing alignment offset between metal layers, and relates to the field of semiconductors. The test structure comprises a first to-be-tested metal wire and a second to-be-tested metal wire, the first to-be-tested metal wire and the second to-be-tested metal wire are distributed in a stacked manner, the conductive test structure comprises a first conductive test part and / or a second conductive test part, the first conductive test part and the first to-be-tested metal layer are distributed on the same layer, and the second conductive test part and the second to-be-tested metal layer are distributed on the same layer. The second conductive test part and the second to-be-tested metal layer are distributed on the same layer; each part of the first conductive test part is equal in line width, and each part of the second conductive test part is also equal in line width; the distances between the first conductive test part and the first metal wire to be tested are equal everywhere, and the distances between the second conductive test part and the second metal wire to be tested are equal everywhere; the first to-be-tested metal wire and the second to-be-tested metal wire are connected through a via hole; the first test pad is connected with the first conductive test part or the second conductive test part; and the second test pad is connected with the first to-be-tested metal wire or the second to-be-tested metal wire.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a semiconductor test structure and a method for testing alignment deviation between metal layers. Background Art

[0002] Memory is widely used in mobile devices such as mobile phones and tablets due to its small size, high integration and fast transmission speed. During the semiconductor structure manufacturing process, due to the influence of process technology and other factors, there is an occasional offset between the upper and lower conductive layers of the conductive column, which in turn affects the electrical performance of the device. Therefore, it is necessary to detect the offset of the upper and lower conductive layers during the manufacturing process to evaluate the process reliability.

[0003] However, when the conventional test structure performs a breakdown voltage test and detects whether there is an overlay shift, the shifts in different directions need to be respectively implemented by different test structures, resulting in more test structures and the test structures occupying a larger area in the cutting path.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The present disclosure provides a semiconductor test structure and a method for testing alignment deviation between metal layers, which can detect deviations in different directions, reduce the number of test structures in a cutting path, and reduce the area occupied by the test structures.

[0006] According to one aspect of the present disclosure, there is provided a semiconductor test structure, comprising: A first metal layer to be tested and a second metal layer to be tested are stacked and distributed, the first metal layer to be tested and the second metal layer to be tested are filled with an interlayer dielectric layer, the first metal layer to be tested includes first metal lines to be tested with equal line widths, and the second metal layer to be tested includes second metal lines to be tested with equal line widths; A conductive test structure, comprising a first conductive test section and / or a second conductive test section, wherein the first conductive test section is distributed in the same layer as the first metal layer to be tested, and the second conductive test section is distributed in the same layer as the second metal layer to be tested; wherein the first conductive test section has a uniform line width at each location, and the second conductive test section also has a uniform line width at each location; the first conductive test section is uniformly spaced from the first metal line to be tested, and the second conductive test section is uniformly spaced from the second metal line to be tested; The first metal line to be tested is connected to the second metal line to be tested via a plurality of vias, and the vias penetrate the interlayer dielectric layer; A first test pad connected to the first conductive test portion or the second conductive test portion; The second test pad is connected to the first metal line to be tested or the second metal line to be tested.

[0007] In an exemplary embodiment of the present disclosure, the first metal line to be tested is a serpentine structure, and the serpentine structure corresponding to the first metal line to be tested is used as a first serpentine structure, one side of the first serpentine structure has a plurality of first grooves distributed at intervals, and the other side has a plurality of second grooves distributed at intervals, and the plurality of first grooves and the plurality of second grooves are alternately distributed; The second metal line to be tested is also a serpentine structure, and the serpentine structure corresponding to the second metal line to be tested is used as a second serpentine structure, one side of the second serpentine structure has a plurality of third grooves distributed at intervals, and the other side has a plurality of fourth grooves distributed at intervals, and the plurality of third grooves and the plurality of fourth grooves are alternately distributed; The first conductive test part includes a first comb structure and a second comb structure, wherein the first comb structure is disposed on one side of the first serpentine structure, and each comb tooth of the first comb structure is correspondingly inserted into a different first groove; the second comb structure is disposed on the other side of the first serpentine structure, and each comb tooth of the second comb structure is correspondingly inserted into a different second groove; The second conductive testing part includes a third comb structure and a fourth comb structure, wherein the third comb structure is placed on one side of the second serpentine structure, and each comb tooth of the third comb structure is respectively inserted into a different third groove; the fourth comb structure is placed on the other side of the second serpentine structure, and each comb tooth of the fourth comb structure is respectively inserted into a different fourth groove.

[0008] In an exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test portion, and the first test pad is connected to the first conductive test portion; or the conductive test structure includes the second conductive test portion, and the first test pad is connected to the second conductive test portion; The first serpentine structure and the second serpentine structure are connected via a plurality of vias, and the second test pad is connected to the first serpentine structure or the second serpentine structure.

[0009] In an exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test portion, and the first test pad is connected to the first comb-shaped structure or the second comb-shaped structure.

[0010] In an exemplary embodiment of the present disclosure, the conductive test structure includes the second conductive test portion, and the first test pad is connected to the third comb-shaped structure or the fourth comb-shaped structure.

[0011] In an exemplary embodiment of the present disclosure, the first test pad is connected to any one of the first comb structure, the second comb structure, the third comb structure and the fourth comb structure, and the second test pad is connected to the first serpentine structure or the second serpentine structure.

[0012] In an exemplary embodiment of the present disclosure, the first metal wire to be tested includes a plurality of first comb-type structures interconnected with each other, the first comb-type structure includes a first comb spine and a plurality of first comb teeth located on one side or both sides of the first comb spine, and the plurality of first comb teeth and the first comb spine form a plurality of first tooth gaps distributed at intervals; The second metal wire to be tested includes a plurality of second comb-shaped structures interconnected with each other, the second comb-shaped structures include a second comb spine and a plurality of second comb teeth located on one side or both sides of the second comb spine, and the plurality of second comb teeth and the second comb spine form a plurality of second tooth gaps distributed at intervals; The first conductive testing part comprises a third comb-shaped structure, and each comb tooth of the third comb-shaped structure is respectively inserted into a different first tooth gap; The second conductive testing portion includes a fourth comb-shaped structure, and each comb tooth of the fourth comb-shaped structure is correspondingly inserted into a different second tooth gap.

[0013] In an exemplary embodiment of the present disclosure, the first comb-type structure and the second comb-type structure are connected through a plurality of vias, and the second test pad is connected to the first comb-type structure or the second comb-type structure.

[0014] In an exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test portion, and the first test pad is connected to the third comb-type structure.

[0015] In an exemplary embodiment of the present disclosure, the conductive test structure includes the second conductive test portion, and the first test pad is connected to the fourth comb-shaped structure.

[0016] In an exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test portion and the second conductive test portion, and the first comb-type structure and the second comb-type structure are connected through a plurality of vias.

[0017] In an exemplary embodiment of the present disclosure, the first test pad is connected to the third comb-type structure or the fourth comb-type structure, and the second test pad is connected to the first comb-type structure or the second comb-type structure.

[0018] In an exemplary embodiment of the present disclosure, the first conductive test portion is a serpentine structure, and the serpentine structure corresponding to the first conductive test portion is used as a third serpentine structure, one side of the third serpentine structure has a plurality of first recesses distributed at intervals, and the other side has a plurality of second recesses distributed at intervals, and the plurality of first recesses and the plurality of second recesses are alternately distributed; The second conductive test portion is also a serpentine structure, and the serpentine structure corresponding to the second conductive test portion is used as a fourth serpentine structure, one side of the fourth serpentine structure has a plurality of third recesses distributed at intervals, and the other side has a plurality of fourth recesses distributed at intervals, and the plurality of third recesses and the plurality of fourth recesses are alternately distributed; The first metal line to be tested includes a fifth comb structure and a sixth comb structure, wherein the fifth comb structure is placed on one side of the third serpentine structure, and each comb tooth of the fifth comb structure is correspondingly inserted into a different first recess; the sixth comb structure is placed on the other side of the third serpentine structure, and each comb tooth of the sixth comb structure is correspondingly inserted into a different second recess; The second metal line to be tested includes a seventh comb structure and an eighth comb structure, wherein the seventh comb structure is placed on one side of the fourth serpentine structure, and each comb tooth of the seventh comb structure is respectively inserted into a different third recess; the eighth comb structure is placed on the other side of the fourth serpentine structure, and each comb tooth of the eighth comb structure is respectively inserted into a different fourth recess.

[0019] In an exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test portion, and the first test pad is connected to the first conductive test portion; or the conductive test structure includes the second conductive test portion, and the first test pad is connected to the second conductive test portion; or the conductive test structure includes the first conductive test portion and the second conductive test portion, and the first test pad is connected to the first conductive test portion or the second conductive test portion; The fifth comb structure is connected to the seventh comb structure through a plurality of vias, the sixth comb structure is connected to the eighth comb structure through a plurality of vias, and the second test pad is connected to any one of the fifth comb structure, the sixth comb structure, the seventh comb structure or the eighth comb structure.

[0020] According to one aspect of the present disclosure, a method for testing metal layer alignment deviation is provided, wherein the testing method uses any one of the semiconductor test structures described above for testing, and the testing method comprises: Detecting a breakdown voltage between the first metal line to be tested and the first conductive test portion; or detecting a breakdown voltage between the second metal line to be tested and the second conductive test portion; Comparing the breakdown voltage with a preset voltage value, and inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested when the breakdown voltage exceeds a preset deviation range of the preset voltage value; Performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the cross sections in different directions; The existence of the offset phenomenon is determined based on the microscopic morphology image, and the offset direction is determined.

[0021] In an exemplary embodiment of the present disclosure, a breakdown voltage between the first metal line to be tested and the first conductive test part is detected, and the detection process includes: applying a first voltage and a second voltage to the first test pad and the second test pad, respectively, and when a breakdown occurs between the first metal line to be tested and the first conductive test part, the voltage difference between the first voltage and the second voltage is the breakdown voltage.

[0022] In an exemplary embodiment of the present disclosure, a breakdown voltage between the second metal line to be tested and the second conductive test part is detected, and the detection process includes: applying a first voltage and a second voltage to the first test pad and the second test pad, respectively, and when a breakdown occurs between the second metal line to be tested and the second conductive test part, the voltage difference between the first voltage and the second voltage is the breakdown voltage.

[0023] According to one aspect of the present disclosure, a method for testing metal layer alignment deviation is provided, wherein the testing method uses any one of the semiconductor test structures described above for testing; the testing method comprises: Measuring the resistance between the first metal line to be tested and the first conductive test portion; or measuring the resistance between the second metal line to be tested and the second conductive test portion; comparing the resistance with a preset resistance value, and inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested when the resistance exceeds a preset deviation range of the preset resistance value; Performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the cross sections in different directions; The existence of the offset phenomenon is determined based on the microscopic morphology image, and the offset direction is determined.

[0024] In an exemplary embodiment of the present disclosure, the resistance between the first metal line to be tested and the first conductive test part is measured, and the measurement process includes: applying a preset current to flow between the first test pad and the second test pad, and measuring the voltage difference between the first metal line to be tested and the first conductive test part, and the resistance is equal to the ratio of the voltage difference to the preset current.

[0025] In an exemplary embodiment of the present disclosure, the resistance between the second metal line to be tested and the second conductive test part is measured, and the measurement process includes: applying a preset current to flow between the first test pad and the second test pad, and measuring the voltage difference between the second metal line to be tested and the second conductive test part, and the resistance is equal to the ratio of the voltage difference to the preset current.

[0026] The semiconductor test structure and the test method for alignment offset between metal layers disclosed in the present invention can apply voltage to the first test pad and the second test pad respectively to detect the breakdown voltage between the conductive test structure and the first metal line to be tested or the second metal line to be tested; or apply a preset current to flow between the first test pad and the second test pad, measure the resistance between the conductive test structure and the first metal line to be tested or the second metal line to be tested, compare the breakdown voltage or resistance with the preset voltage value or the preset resistance value, and infer that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested when the breakdown voltage or resistance exceeds the preset deviation range of the preset voltage value or the preset resistance value, and the offset direction between the second metal line to be tested and the first metal line to be tested can be further determined by sectioning. That is, in the present invention, through a semiconductor test structure, it is possible to detect whether there is an overlay shift phenomenon between the upper and lower metal lines, and determine the specific direction of the offset, provide a window reference for metal layer offset (overlay shift) for the improvement of semiconductor technology, monitor the process, and help improve process reliability. Due to the limited placement area of ​​the test structure (Testkey), the number of semiconductor test structures that can be placed in the present disclosure is reduced. Compared with the existing solution of placing two different test structures to detect two different direction offsets (overlay shift) respectively, the present disclosure proposes to use one test structure to detect two directions at the same time, which can save the placement area of ​​the semiconductor test structure and reduce the manufacturing cost. At the same time, it can also save test time and test times, and improve test efficiency. In addition, when the breakdown voltage or resistance does not exceed the preset deviation range of the preset voltage value or the preset resistance value, it can be directly determined that there is no offset phenomenon between the first metal line to be tested and the second metal line to be tested, and there is no need to perform slicing, and the test efficiency is higher.

[0027] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0029] Figure 1 FIG. 4 is a schematic diagram of a semiconductor test structure in an embodiment of the present disclosure.

[0030] Figure 2 Schematic diagram of a first metal line to be tested and a first conductive testing portion in an embodiment of the present disclosure.

[0031] Figure 3 FIG. 4 is a schematic diagram of a semiconductor test structure when the conductive test structure includes only the first conductive test portion in an embodiment of the present disclosure.

[0032] Figure 4 FIG. 4 is a schematic diagram of a semiconductor test structure when the conductive test structure includes only the second conductive test portion in an embodiment of the present disclosure.

[0033] Figure 5 It is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the present disclosure only includes the first conductive test portion and the line width of the first metal line to be tested is greater than the line width of the second metal line to be tested.

[0034] Figure 6 It is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the present disclosure only includes the first conductive test portion and the line width of the first metal line to be tested is smaller than the line width of the second metal line to be tested.

[0035] Figure 7 It is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the present disclosure only includes the second conductive test portion and the line width of the first metal line to be tested is greater than the line width of the second metal line to be tested.

[0036] Figure 8 It is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the present disclosure only includes the second conductive test portion and the line width of the first metal line to be tested is smaller than the line width of the second metal line to be tested.

[0037] Fig. 9 FIG. 4 is a schematic diagram of a semiconductor test structure in an embodiment of the present disclosure.

[0038] Fig.10 FIG. 4 is a schematic diagram of a semiconductor test structure in an embodiment of the present disclosure.

[0039] Fig.111 is a top view of a first metal line to be tested, a second metal line to be tested, a first conductive test portion, and a second conductive test portion in one embodiment of the present disclosure.

[0040] Fig.12 FIG. 4 is a schematic diagram of a semiconductor test structure in an embodiment of the present disclosure.

[0041] Fig.13 Schematic diagram of a method for testing alignment deviation between metal layers in an embodiment of the present disclosure.

[0042] Fig.14 Schematic diagram of a method for testing alignment deviation between metal layers in another embodiment of the present disclosure.

[0043] Description of reference numerals: 1. First metal line to be tested; 101. First groove; 102. Second groove; 11. First comb-shaped structure; 111. First comb ridge; 112. First comb tooth; 113. First tooth gap; 12. First connecting line; 13. Fifth comb-shaped structure; 131. Comb teeth of fifth comb-shaped structure; 14. Sixth comb-shaped structure; 141. Comb teeth of sixth comb-shaped structure; 15. Seventh comb-shaped structure; 151. Comb teeth of seventh comb-shaped structure; 16. Eighth comb-shaped structure; 161. Comb teeth of eighth comb-shaped structure; 2. Second metal line to be tested; 201. Third groove; 202. Fourth groove; 3. Conductive test structure; 31. First conductive test structure Test part; 301, first recess; 302, second recess; 311, first comb-like structure; 3111, comb teeth of the first comb-like structure; 312, second comb-like structure; 3121, comb teeth of the second comb-like structure; 313, third comb-like structure; 3131, third comb ridge; 3132, third comb teeth; 314, third connecting line; 32, second conductive test part; 303, third recess; 304, fourth recess; 321, third comb-like structure; 3211, comb teeth of the third comb-like structure; 322, fourth comb-like structure; 3221, comb teeth of the fourth comb structure; 4, via; 5, first test pad; 6, second test pad. DETAILED DESCRIPTION

[0044] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0045] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0046] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusion and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second"... "eighth", etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0047] In the semiconductor manufacturing industry, reliability testing is a key step in ensuring product process stability and reliability. This process usually relies on various test structures designed on the wafer to evaluate and verify performance under different conditions. Among them, breakdown voltage (or resistance) is one of the important indicators for measuring the insulation performance of the dielectric layer, which is crucial for evaluating the voltage resistance of semiconductor devices.

[0048] In the traditional breakdown voltage test structure design, the metal layer groups on the upper and lower sides of the dielectric layer are usually designed independently, and in order to meet the test requirements, these metal layer groups (i.e., test structures) will occupy a certain placement area. However, with the continuous advancement of semiconductor process technology, the structures on the wafer are becoming more and more complex. Most of the test structures are placed in the cutting path between two adjacent chips on the wafer, and are used as process monitoring structures. The setting position of the test structure greatly limits the placement area and number of test structures of the same test type. At the same time, alignment problems in the process, such as alignment deviations between the upper and lower metal layers and the middle through-holes, or between different photolithography layers, i.e., overlay offset, have a significant impact on the test results. This offset may not only lead to inaccurate test results for breakdown voltage or resistance, but may also affect the performance and reliability of the entire semiconductor device.

[0049] At present, the test structures arranged in the same direction of the metal layer show a single characteristic when detecting the offset direction of the cover layer, that is, they can only detect the offset in a specific direction. In order to comprehensively evaluate the offset situation, it is usually necessary to design multiple test structures in different directions, which undoubtedly increases the complexity of the test and the occupied wafer area, and also affects the test efficiency.

[0050] Based on this, the present disclosure provides a semiconductor test structure, such as Figure 1 As shown, the test structure includes a first metal layer to be tested, a second metal layer to be tested, a conductive test structure 3, a first test pad 5 and a second test pad 6, wherein: The first metal layer to be tested and the second metal layer to be tested are stacked and arranged, the first metal layer to be tested and the second metal layer to be tested are filled with an interlayer dielectric layer, the first metal layer to be tested includes first metal lines 1 to be tested with equal line width, and the second metal layer to be tested includes second metal lines 2 to be tested with equal line width; The conductive test structure 3 includes a first conductive test portion 31 and / or a second conductive test portion 32, wherein the first conductive test portion 31 is distributed in the same layer as the first metal layer to be tested, and the second conductive test portion 32 is distributed in the same layer as the second metal layer to be tested; wherein the line width of the first conductive test portion 31 is the same at all locations, and the line width of the second conductive test portion 32 is also the same at all locations; the spacing between the first conductive test portion 31 and the first metal line 1 to be tested is the same at all locations, and the spacing between the second conductive test portion 32 and the second metal line 2 to be tested is the same at all locations; The first metal line 1 to be tested is connected to the second metal line 2 to be tested via a plurality of vias 4, and the vias 4 penetrate the interlayer dielectric layer (not shown in the figure); The first test pad 5 is connected to the first conductive test portion 31 or the second conductive test portion 32; The second test pad 6 is connected to the first metal line 1 to be tested or the second metal line 2 to be tested.

[0051] The semiconductor test structure disclosed in the present invention can apply voltage to the first test pad 5 and the second test pad 6 respectively to detect the breakdown voltage between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested; or apply a preset current to flow between the first test pad 5 and the second test pad 6, measure the resistance between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested, compare the breakdown voltage or resistance with the preset voltage value or the preset resistance value, and infer that there is an offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested when the breakdown voltage or resistance exceeds the preset deviation range of the preset voltage value or the preset resistance value, and the offset direction between the second metal line 2 to be tested and the first metal line 1 to be tested can be further determined by sectioning. That is, in the present invention, a semiconductor test structure can be used to detect whether there is an offset phenomenon between the upper and lower metal lines, and determine the specific direction of the offset, providing data support for the improvement of semiconductor processes and helping to improve process reliability. Due to the limited placement area of ​​the test structure (Testkey), the number of semiconductor test structures that can be placed in the present disclosure is reduced. Compared with the existing solution of placing two different test structures to detect two different direction offsets (overlay shift) respectively, the present disclosure proposes to use one test structure to detect two directions at the same time, which can save the placement area of ​​the semiconductor test structure and reduce the manufacturing cost. At the same time, it can also save test time and test times, and improve test efficiency. In addition, when the breakdown voltage or resistance does not exceed the preset deviation range of the preset voltage value or the preset resistance value, it can be directly determined that there is no offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested, and there is no need to perform slicing, and the test efficiency is higher.

[0052] The following is a detailed description of the various parts and specific details of the semiconductor test structure disclosed in the present invention: The first metal layer to be tested and the second metal layer to be tested can be stacked and distributed. In some embodiments of the present disclosure, the first metal layer to be tested and the second metal layer to be tested are filled with an interlayer dielectric layer. Figure 1 As shown, the first metal layer to be tested may include first metal lines 1 to be tested with equal line widths, and the second metal layer to be tested may include second metal lines 2 to be tested with equal line widths. That is, the line widths of the first metal lines 1 to be tested in the first metal layer to be tested are equal everywhere, and at the same time, the line widths of the second metal lines 2 to be tested in the second metal layer to be tested are equal everywhere. The line widths of the first metal line 1 to be tested and the second metal line 2 to be tested may be equal or unequal, and are not specifically limited here.

[0053] In an exemplary embodiment of the present disclosure, the line width of the first metal line 1 to be tested and the line width of the second metal line 2 to be tested both follow the minimum design rule, that is, the line width of the first metal line 1 to be tested and the second metal line 2 to be tested are the minimum line widths based on satisfying their own conductive properties.

[0054] The material of the first metal wire 1 to be tested can be a material with strong conductivity, for example, its material can be copper, aluminum, tungsten or titanium nitride, of course, it can also be other materials with strong conductivity, which are not listed here. The material of the interlayer dielectric layer can be an insulating material, for example, its material can be silicon oxide or silicon nitride. The material of the second metal wire 2 to be tested can also be a material with strong conductivity, for example, its material can be copper, aluminum, tungsten or titanium nitride, of course, it can also be other materials with strong conductivity, which are not listed here.

[0055] In some embodiments of the present disclosure, Figure 2 As shown, the first metal wire 1 to be tested can be a serpentine structure, an S-shaped structure or a straight structure. When the first metal wire 1 to be tested is a serpentine structure, in order to facilitate the distinction between the first metal wire 1 to be tested and the second metal wire 2 to be tested, the serpentine structure corresponding to the first metal wire 1 to be tested can be used as the first serpentine structure. One side of the first serpentine structure has a plurality of first grooves 101 distributed at intervals, and the other side has a plurality of second grooves 102 distributed at intervals. The plurality of first grooves 101 and the plurality of second grooves 102 are alternately distributed. It should be noted that the first groove 101 and the second groove 102 are groove-like structures defined by the structure of the first serpentine structure itself.

[0056] Please continue to see Figure 1 As shown, the structure of the second metal wire 2 to be tested may also be a serpentine structure, an S-shaped structure or a straight structure; in the present disclosure, the second metal wire 2 to be tested is taken as a serpentine structure as an example to explain its setting details and the coordination relationship with other structures. For the sake of easy distinction, the serpentine structure corresponding to the second metal wire 2 to be tested can be used as a second serpentine structure, one side of the second serpentine structure has a plurality of third grooves 201 distributed at intervals, and the other side has a plurality of fourth grooves 202 distributed at intervals, and the plurality of third grooves 201 and the plurality of fourth grooves 202 are alternately distributed. It should be noted that the third groove 201 and the fourth groove 202 are groove-like structures defined by the structure of the second serpentine structure itself.

[0057] In an exemplary embodiment of the present disclosure, please continue to refer to Figure 1 and Figure 2 As shown, the first metal line 1 to be tested and the second metal line 2 to be tested can be connected through a plurality of vias 4, and the vias 4 can penetrate the interlayer dielectric layer, and the vias 4 are filled with conductive materials, that is, the first metal line 1 to be tested and the second metal line 2 to be tested can be connected through the conductive materials. The line width of the vias 4 also follows the minimum line width principle (min design rule), that is, the line width of the vias 4 is the minimum line width based on satisfying its own conductive characteristics.

[0058] In some embodiments of the present disclosure, Figure 2 and Figure 3 As shown, the conductive test structure 3 may include a first conductive test portion 31, and the first conductive test portion 31 is distributed in the same layer as the first metal layer to be tested. The first conductive test portion 31 has a uniform line width at each location, that is, the line width of each region in the first conductive test portion 31 is uniform at each location; and the spacing between the first conductive test portion 31 and the first metal line 1 to be tested is uniform at each location (that is, Figure 2 It should be noted that the line width of the first conductive test portion 31 follows the minimum line width principle (min design rule), that is, the line width of the first conductive test portion 31 is the minimum line width based on its own conductive characteristics. The spacing between the first conductive test portion 31 and the first metal line 1 to be tested is the minimum spacing that can ensure that the two are not conductive or coupled to each other.

[0059] The shape of the first conductive test portion 31 matches the shape of the first metal line 1 to be tested in the first metal layer to be tested. For example, when the first metal line 1 to be tested is a straight line, the first conductive test portion 31 is also a straight line; when the shape of the first metal line 1 to be tested is a serpentine or S-shaped, the first conductive test portion 31 is a comb-shaped structure (such as Figure 1-Figure 3 as shown).

[0060] In other embodiments of the present disclosure, Figure 4 As shown, the conductive test structure 3 may include a second conductive test portion 32, and the second conductive test portion 32 is distributed in the same layer as the second metal layer to be tested. The second conductive test portion 32 also has equal line widths at various locations, that is, the line widths of various regions in the second conductive test portion 32 are equal everywhere. The spacing between the second conductive test portion 32 and the second metal line 2 to be tested is equal everywhere; it should be noted that the line width of the second conductive test portion 32 follows the minimum line width principle (min design rule), that is, the line width of the second conductive test portion 32 is the minimum line width based on satisfying its own conductive characteristics. The spacing between the second conductive test portion 32 and the second metal line 2 to be tested is the minimum spacing that can ensure that the two are not conductive or coupled to each other.

[0061] The shape of the second conductive test portion 32 matches the shape of the second metal line 2 to be tested in the second metal layer to be tested. For example, when the second metal line 2 to be tested is a straight line, the second conductive test portion 32 is also a straight line; when the shape of the second metal line 2 to be tested is a serpentine or S-shaped, the second conductive test portion 32 is a comb-shaped structure (such as Figure 1 and Figure 4 as shown).

[0062] In some further embodiments of the present disclosure, please continue to refer to Figure 1As shown, the conductive test structure 3 may include a first conductive test portion 31 and a second conductive test portion 32, wherein the first conductive test portion 31 is distributed in the same layer as the first metal layer to be tested, and the second conductive test portion 32 is distributed in the same layer as the second metal layer to be tested. The first conductive test portion 31 has a uniform line width at each location, and the second conductive test portion 32 also has a uniform line width at each location; the first conductive test portion 31 and the first metal line 1 to be tested have a uniform spacing at each location, and the second conductive test portion 32 and the second metal line 2 to be tested have a uniform spacing at each location.

[0063] In an exemplary embodiment of the present disclosure, please continue to refer to Figure 1-Figure 3 As shown, when the first metal line 1 to be tested is a serpentine structure, the first conductive test part 31 may include a first comb-like structure 311 and a second comb-like structure 312, wherein the first comb-like structure 311 is placed on one side of the first serpentine structure, the number of comb teeth 3111 of the first comb-like structure matches the number of first grooves 101, and the comb teeth 3111 of the first comb-like structure are respectively inserted into different first grooves 101, and the spacing between all areas of the comb teeth 3111 of the first comb-like structure and the first metal line 1 to be tested around them is equal. The second comb-like structure 312 is placed on the other side of the first serpentine structure, the number of comb teeth 3121 of the second comb-like structure matches the number of second grooves 102, and the comb teeth 3121 of the second comb-like structure are respectively inserted into different second grooves 102, and the spacing between all areas of the comb teeth 3121 of the second comb-like structure and the first metal line 1 to be tested around them is equal.

[0064] Please continue to see Figure 1 and Figure 4 As shown, when the second metal line 2 to be tested is a serpentine structure, the second conductive test part 32 may include a third comb-like structure 321 and a fourth comb-like structure 322, wherein the third comb-like structure 321 is placed on one side of the second serpentine structure, the number of comb teeth 3211 of the third comb-like structure matches the number of third grooves 201, and the comb teeth 3211 of the third comb-like structure are respectively inserted into different third grooves 201, and the spacing between all areas of the comb teeth 3211 of the third comb-like structure and the second metal line 2 to be tested around them is equal. The fourth comb-like structure 322 is placed on the other side of the second serpentine structure, the number of comb teeth 3221 of the fourth comb-like structure matches the number of fourth grooves 202, and the comb teeth 3221 of the fourth comb-like structure are respectively inserted into different fourth grooves 202, and the spacing between all areas of the comb teeth 3221 of the fourth comb-like structure and the second metal line 2 to be tested around them is equal.

[0065] Please continue to see Figure 1 , Figure 3 and Figure 4As shown, the first test pad 5 may be in a sheet shape, and its material may be a conductive material, for example, its material may be copper. The first test pad 5 may be connected to the first conductive test portion 31 or the second conductive test portion 32. Figure 3 As shown, when the conductive test structure 3 only includes the first conductive test part 31, the first serpentine structure and the second serpentine structure are connected through multiple vias 4, and the first test pad 5 is connected to the first conductive test part 31. For example, the first test pad 5 can be connected to the first comb structure 311 in the first conductive test part 31, or connected to the second comb structure 312 in the first conductive test part 31. No special limitation is made on the connection area between the first test pad 5 and the first conductive test part 31.

[0066] Please continue to see Figure 4 As shown, when the conductive test structure 3 only includes the second conductive test part 32, the first serpentine structure and the second serpentine structure are connected through multiple vias 4, and the first test pad 5 is connected to the second conductive test part 32. For example, the first test pad 5 can be connected to the third comb-shaped structure 321 in the second conductive test part 32, or connected to the fourth comb-shaped structure 322 in the second conductive test part 32. No special limitation is made on the connection area between the first test pad 5 and the second conductive test part 32.

[0067] When the conductive test structure 3 includes both the first conductive test portion 31 and the second conductive test portion 32, the first serpentine structure and the second serpentine structure may be connected through a plurality of vias 4. The first test pad 5 may be connected to the first conductive test portion 31 or the second conductive test portion 32. For example, the first test pad 5 may be connected to any one of the first comb-shaped structure 311, the second comb-shaped structure 312, the third comb-shaped structure 321, and the fourth comb-shaped structure 322.

[0068] Please continue to see Figure 1 , Figure 3 and Figure 4As shown, the second test pad 6 may also be in the form of a sheet, and its material may be a conductive material, for example, its material may be copper. The second test pad 6 may be connected to the end of the first metal line 1 to be tested or the end of the second metal line 2 to be tested. For example, the second test pad 6 may be connected to the first serpentine structure or the second serpentine structure. Voltages may be applied to the first test pad 5 and the second test pad 6, respectively, to detect the breakdown voltage between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested; or a preset current may be applied between the first test pad 5 and the second test pad 6, to measure the resistance between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested, and the breakdown voltage or resistance may be compared with the preset voltage value or the preset resistance value. When the breakdown voltage or resistance exceeds the preset deviation range of the preset voltage value or the preset resistance value, it is inferred that there is an offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested, and the offset direction between the second metal line 2 to be tested and the first metal line 1 to be tested may be further determined by sectioning.

[0069] It should be noted that when the first test pad 5 is connected to the first comb structure 311 or the second comb structure 312, the breakdown voltage or resistance finally detected is the breakdown voltage or resistance corresponding to the first metal line 1 to be tested; when the first test pad 5 is connected to the third comb structure 321 or the fourth comb structure 322, the breakdown voltage or resistance finally detected is the breakdown voltage or resistance corresponding to the second metal line 2 to be tested.

[0070] In an exemplary embodiment of the present disclosure, when the line widths of the first metal line 1 to be tested and the second metal line 2 to be tested are not equal, and the conductive test structure 3 only includes the first conductive test part 31 or only includes the second conductive test part 32, the line width of the first metal line 1 to be tested is equal to the line width of the corresponding first conductive test part 31, or the line width of the second conductive test part 32 is equal to the line width of the corresponding second metal line 2 to be tested.

[0071] In some embodiments of the present disclosure, Figure 5 As shown, the conductive test structure 3 only includes the first conductive test portion 31, the line width of the first metal line 1 to be tested is greater than the line width of the second metal line 2 to be tested, and the line width of the first conductive test portion 31 is equal to the line width of the first metal line 1 to be tested. Figure 6 As shown, the conductive test structure 3 only includes the first conductive test portion 31, the line width of the first metal line 1 to be tested is smaller than the line width of the second metal line 2 to be tested, and the line width of the first conductive test portion 31 is equal to the line width of the first metal line 1 to be tested. Figure 7As shown, the conductive test structure 3 only includes the second conductive test portion 32, the line width of the first metal line 1 to be tested is greater than the line width of the second metal line 2 to be tested, and the line width of the second conductive test portion 32 is equal to the line width of the second metal line 2 to be tested. Figure 8 As shown, the conductive test structure 3 only includes the second conductive test portion 32 , the line width of the first metal line 1 to be tested is smaller than the line width of the second metal line 2 to be tested, and the line width of the second conductive test portion 32 is equal to the line width of the second metal line 2 to be tested.

[0072] In an exemplary embodiment of the present disclosure, when the line widths of the first metal line 1 to be tested and the second metal line 2 to be tested are not equal, and the conductive test structure 3 includes not only the first conductive test portion 31 but also the second conductive test portion 32, the metal line to be tested with a larger line width and the line width of the conductive test portion corresponding thereto are equal, while the metal line to be tested with a smaller line width and the line width of the conductive test portion corresponding thereto are not equal. Fig. 9 As shown in FIG. 1 , when the line width of the first metal line 1 to be tested is greater than the line width of the second metal line 2 to be tested, the line width of the first conductive test portion 31 is equal to the line width of the first metal line 1 to be tested; the line width of the second conductive test portion 32 is greater than the line width of the second metal line 2 to be tested, and at the same time, the line width of the second conductive test portion 32 is greater than the line width of the first conductive test portion 31. The line width of the second conductive test portion 32 is: the distance between the center line of the first conductive test portion 31 and the center line of the first metal line 1 to be tested (i.e. Fig. 9 e) minus the distance between the center line of the second conductive test portion 32 and the center line of the second metal wire 2 to be tested (i.e. Fig. 9 f), and then subtract the line width of the second metal line 2 to be tested. Fig.10 As shown, when the line width of the first metal line 1 to be tested is smaller than the line width of the second metal line 2 to be tested, the line width of the second conductive test portion 32 is equal to the line width of the second metal line 2 to be tested; the line width of the first conductive test portion 31 is larger than the line width of the first metal line 1 to be tested, and at the same time, the line width of the first conductive test portion 31 is larger than the line width of the second conductive test portion 32. And the line width of the first conductive test portion 31 is: the distance between the center line of the second conductive test portion 32 and the center line of the second metal line 2 to be tested (i.e. Fig.10 g) minus the distance between the center line of the first conductive test part 31 and the center line of the first metal wire 1 to be tested (i.e. Fig.10 h), minus the line width of the first metal line 1 to be tested.

[0073] In an exemplary embodiment of the present disclosure, Fig.11As shown, the shape of the first metal line to be tested 1 and / or the second metal line to be tested 2 can be interchanged with the shape of the conductive test structure 3. For example, the shape of the conductive test structure 3 (for example, the first conductive test portion 31 or the second conductive test portion 32) can be a serpentine structure, and correspondingly, the shape of the first metal line to be tested 1 and the second metal line to be tested 2 can both be a comb-shaped structure.

[0074] In an exemplary embodiment of the present disclosure, the first conductive test part 31 may be a serpentine structure, and the serpentine structure corresponding to the first conductive test part 31 may be used as a third serpentine structure, one side of the third serpentine structure has a plurality of first recesses 301 distributed at intervals, and the other side has a plurality of second recesses 302 distributed at intervals, and the first recesses 301 and the plurality of second recesses 302 are alternately distributed. It should be noted that the first recesses 301 and the second recesses 302 are groove-shaped structures defined by the structure of the third serpentine structure itself.

[0075] In some embodiments of the present disclosure, please continue to refer to Fig.11 As shown, when the first conductive test part 31 is a serpentine structure, the first metal line 1 to be tested in the first metal layer to be tested includes 2 metal lines, and both metal lines are comb-shaped structures. For the convenience of distinction, the first metal line 1 to be tested can be defined as including a fifth comb-shaped structure 13 and a sixth comb-shaped structure 14, wherein the fifth comb-shaped structure 13 is placed on one side of the third serpentine structure, the number of comb teeth 131 of the fifth comb-shaped structure matches the number of first recesses 301, the comb teeth 131 of the fifth comb-shaped structure are respectively inserted into different first recesses 301, and the spacing between all areas of the comb teeth 131 of the fifth comb-shaped structure and the first conductive test part 31 around it is equal; the sixth comb-shaped structure 14 is placed on the other side of the third serpentine structure, the number of comb teeth 141 of the sixth comb-shaped structure matches the number of second recesses 302, and the comb teeth 141 of the sixth comb-shaped structure are respectively inserted into different second recesses 302, and the spacing between all areas of the comb teeth 141 of the sixth comb-shaped structure and the first conductive test part 31 around it is equal.

[0076] In some embodiments of the present disclosure, please continue to refer to Fig.11 As shown, the second conductive test part 32 may also be a serpentine structure, and the serpentine structure corresponding to the second conductive test part 32 may be used as a fourth serpentine structure, one side of the fourth serpentine structure has a plurality of third recesses 303 distributed at intervals, and the other side has a plurality of fourth recesses 304 distributed at intervals, and the plurality of third recesses 303 and the plurality of fourth recesses 304 are alternately distributed. It should be noted that the third recesses 303 and the fourth recesses 304 are groove-shaped structures defined by the structure of the fourth serpentine structure itself.

[0077] In some embodiments of the present disclosure, when the second conductive test part 32 is a serpentine structure, the second metal line 2 to be tested in the first metal layer to be tested includes 2 metal lines, and both metal lines are comb-shaped structures. For the convenience of distinction, the second metal line 2 to be tested can be defined as including a seventh comb-shaped structure 15 and an eighth comb-shaped structure 16, wherein the seventh comb-shaped structure 15 is placed on one side of the third serpentine structure, the number of comb teeth 151 of the seventh comb-shaped structure matches the number of third recesses 303, the comb teeth 151 of the seventh comb-shaped structure are respectively inserted into different third recesses 303, and all areas of the comb teeth 151 of the seventh comb-shaped structure are equal to the spacing between the second conductive test part 32 around it; the eighth comb-shaped structure 16 is placed on the other side of the third serpentine structure, the number of comb teeth 161 of the eighth comb-shaped structure matches the number of fourth recesses 304, and the comb teeth 161 of the eighth comb-shaped structure are respectively inserted into different fourth recesses 304, and all areas of the comb teeth 161 of the eighth comb-shaped structure are equal to the spacing between the second conductive test part 32 around it.

[0078] In some embodiments of the present disclosure, when the conductive test structure 3 includes only the first conductive test part 31, the first test pad 5 is connected to the first conductive test part 31. At this time, the fifth comb-shaped structure 13 is connected to the seventh comb-shaped structure 15 through a plurality of vias 4, the sixth comb-shaped structure 14 is connected to the eighth comb-shaped structure 16 through a plurality of vias 4, and the second test pad 6 is connected to any one of the fifth comb-shaped structure 13, the sixth comb-shaped structure 14, the seventh comb-shaped structure 15 or the eighth comb-shaped structure 16.

[0079] In some embodiments of the present disclosure, when the conductive test structure 3 includes only the second conductive test portion 32, the first test pad 5 is connected to the second conductive test portion 32. At this time, the fifth comb-shaped structure 13 is connected to the seventh comb-shaped structure 15 through a plurality of vias 4, the sixth comb-shaped structure 14 is connected to the eighth comb-shaped structure 16 through a plurality of vias 4, and the second test pad 6 is connected to any one of the fifth comb-shaped structure 13, the sixth comb-shaped structure 14, the seventh comb-shaped structure 15 or the eighth comb-shaped structure 16.

[0080] In some embodiments of the present disclosure, when the conductive test structure 3 includes both the first conductive test part 31 and the second conductive test part 32, the first test pad 5 is connected to the first conductive test part 31 or the second conductive test part 32. At this time, the fifth comb-shaped structure 13 is connected to the seventh comb-shaped structure 15 through a plurality of vias 4, the sixth comb-shaped structure 14 is connected to the eighth comb-shaped structure 16 through a plurality of vias 4, and the second test pad 6 is connected to any one of the fifth comb-shaped structure 13, the sixth comb-shaped structure 14, the seventh comb-shaped structure 15 or the eighth comb-shaped structure 16.

[0081] In an exemplary embodiment of the present disclosure, Fig.12As shown, the first metal wire 1 to be tested may include a plurality of first comb-type structures 11 that are interconnected, and the first comb-type structure 11 includes a first comb spine 111 and a plurality of first comb teeth 112 located on one side or both sides of the first comb spine 111. Each first comb tooth 112 may be distributed in parallel, and the plurality of first comb teeth 112 and the first comb spine 111 form a plurality of first tooth gaps 113 that are spaced apart along the length direction of the first comb spine 111. The ends of the plurality of first comb spines 111 in the plurality of first comb-type structures 11 that are located on the same side may be connected together through the first connecting line 12.

[0082] The second metal wire 2 to be tested may include a plurality of second comb-type structures (not shown in the figure) interconnected with each other, the second comb-type structure includes a second comb spine and a plurality of second comb teeth located on one side or both sides of the second comb spine, each second comb tooth may be distributed in parallel, and the plurality of second comb teeth and the second comb spine form a plurality of second tooth gaps spaced apart along the length direction of the second comb spine. The ends of the plurality of second comb spines in the plurality of second comb-type structures located on the same side may be connected together by a second connecting line.

[0083] Please continue to see Fig.12 As shown, the first conductive test part 31 may include a plurality of interconnected third comb-type structures 313, the third comb-type structure 313 includes a third comb ridge 3131 and a plurality of third comb teeth 3132 located on one side or both sides of the third comb ridge 3131, and the plurality of third comb teeth 3132 may be spaced and distributed along the length direction of the third comb ridge 3131. Each third comb tooth 3132 in the third comb-type structure 313 may be inserted into a different first tooth gap 113. The ends of the plurality of third comb ridges 3131 in the plurality of third comb-type structures 313 located on the same side may be connected together through a third connecting line 314, and the third connecting line 314 and the first connecting line 12 are located on different sides.

[0084] The second conductive test part 32 may include a plurality of interconnected fourth comb-type structures, the fourth comb-type structure including a fourth comb ridge and a plurality of fourth comb teeth located on one side or both sides of the fourth comb ridge, and the plurality of fourth comb teeth may be spaced apart along the length direction of the fourth comb ridge. Each fourth comb tooth in the fourth comb-type structure may be inserted into a different second tooth gap respectively. The ends of the plurality of fourth comb ridges in the plurality of fourth comb-type structures located on the same side may be connected together by a fourth connecting line, and the fourth connecting line and the second connecting line are located on different sides.

[0085] In an exemplary embodiment of the present disclosure, the first comb-shaped structure 11 and the second comb-shaped structure may be connected through a plurality of vias 4. When the conductive test structure 3 includes only the first conductive test portion 31, the first test pad 5 is connected to the first conductive test portion 31, for example, the first test pad 5 is connected to the third comb-shaped structure 313 in the first conductive test portion 31; for example, the first test pad 5 is connected to the third connection line 314 connecting the third comb-shaped structures 313 in the first conductive test portion 31.

[0086] When the conductive test structure 3 only includes the second conductive test part 32, the first test pad 5 is connected to the second conductive test part 32. For example, the first test pad 5 is connected to the fourth comb-shaped structure in the second conductive test part 32. For example, the first test pad 5 is connected to the fourth connection line connecting each fourth comb-shaped structure in the second conductive test part 32.

[0087] In an exemplary embodiment of the present disclosure, the conductive test structure 3 includes not only the first conductive test part 31, but also the second conductive test part 32. The first comb-type structure 11 and the second comb-type structure are connected through a plurality of vias 4. At this time, the first test pad 5 can be connected to the third comb-type structure 313, or the first test pad 5 can be connected to the fourth comb-type structure.

[0088] The second test pad 6 can be connected to the first comb-type structure 11 or the second comb-type structure. For example, the second test pad 6 can be connected to the first connecting line 12 connecting each first comb ridge 111 in each first comb-type structure 11, or the second test pad 6 can be connected to the second connecting line connecting each second comb ridge in each second comb-type structure.

[0089] The present disclosure also provides a method for testing the alignment deviation between metal layers. The method uses the semiconductor test structure in any of the above embodiments to perform the test. Fig.13 As shown, the test method may include steps S110 to S140, wherein: Step S110 , detecting a breakdown voltage between a first metal line to be tested and a first conductive test portion; or detecting a breakdown voltage between a second metal line to be tested and a second conductive test portion.

[0090] In some embodiments of the present disclosure, the detection process of detecting the breakdown voltage between the first metal line to be tested 1 and the first conductive test part 31 includes: applying a first voltage and a second voltage to the first test pad 5 and the second test pad 6 connected to the first conductive test part 31, respectively. The voltage value of the first voltage is different from the voltage value of the second voltage. For example, the first voltage may be a low voltage, and the second voltage may be a variable voltage value. The voltage value corresponding to the second voltage may be gradually increased to the second test pad 6 until a breakdown occurs between the first metal line to be tested 1 and the first conductive test part 31, and when a breakdown occurs between the first metal line to be tested 1 and the first conductive test part 31, the voltage difference between the first voltage and the second voltage may be used as the breakdown voltage.

[0091] In some embodiments of the present disclosure, the detection process of detecting the breakdown voltage between the second metal line 2 to be tested and the second conductive test part 32 includes: applying a first voltage and a second voltage to the first test pad 5 and the second test pad 6 connected to the second conductive test part 32, respectively. The voltage value of the first voltage is different from the voltage value of the second voltage. For example, the first voltage may be a low voltage, and the second voltage may be a variable voltage value. The voltage value corresponding to the second voltage may be gradually increased to the second test pad 6 until a breakdown occurs between the second metal line 2 to be tested and the second conductive test part 32, and when a breakdown occurs between the second metal line 2 to be tested and the second conductive test part 32, the voltage difference between the first voltage and the second voltage may be used as the breakdown voltage.

[0092] Step S120 , comparing the breakdown voltage with a preset voltage value, and when the breakdown voltage exceeds a preset deviation range of the preset voltage value, inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested.

[0093] The preset voltage value may be a theoretical value or an empirical value of a breakdown voltage when there is no offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested, which is estimated by calculation according to process conditions. The preset deviation range of the preset voltage value may be a deviation range of the breakdown voltage that does not affect the electrical properties of the first metal line 1 to be tested and the second metal line 2 to be tested, that is, the preset deviation range of the preset voltage value is an allowable range of the actual measured value of the breakdown voltage deviating from the theoretical value or the empirical value of the breakdown voltage.

[0094] Step S130 , performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the sections in different directions.

[0095] The microscopic topography image may be a scanning electron microscope image of the semiconductor test structure.

[0096] Step S140, determining the existence of the offset phenomenon and the offset direction according to the microscopic topography image.

[0097] Whether there is an offset between the first metal layer to be tested and the second metal layer to be tested in the semiconductor test structure can be observed through scanning electron microscope images of the semiconductor test structure in different directions; if the first metal layer to be tested and the second metal layer to be tested are found to be offset through microscopic morphology analysis, it indicates that there are defects in the process used to form the first metal layer to be tested and the second metal layer to be tested, and the process needs to be improved. That is, the design of the semiconductor test structure and the test method for alignment offset between metal layers disclosed in the present invention can provide data support for process improvement, which is helpful to improve product yield and product reliability.

[0098] The present disclosure also provides a method for testing the alignment deviation between metal layers. The method uses the semiconductor test structure in any of the above embodiments to perform the test. Fig.14 As shown, the testing method may include steps S210 to S240, wherein: Step S210 , measuring the resistance between the first metal line to be tested and the first conductive test portion; or measuring the resistance between the second metal line to be tested and the second conductive test portion.

[0099] In some embodiments of the present disclosure, the measurement process of measuring the resistance between the first metal wire 1 to be tested and the first conductive test part 31 includes: applying a preset current to flow between the first test pad 5 and the second test pad 6 connected to the first conductive test part 31, measuring the voltage difference between the first metal wire 1 to be tested and the first conductive test part 31, and the resistance is equal to the ratio of the voltage difference to the current. It should be noted that the preset current can be any current value, but the preset currents applied to the first test pad 5 and the second test pad 6 are respectively equal. Correspondingly, the measurement process of measuring the resistance between the second metal wire 2 to be tested and the second conductive test part 32 includes: applying a preset current to flow between the first test pad 5 and the second test pad 6 connected to the second conductive test part 32, measuring the voltage difference between the second metal wire 2 to be tested and the second conductive test part 32, and the resistance is equal to the ratio of the voltage difference to the current.

[0100] Step S220 , comparing the resistance with a preset resistance value, and when the resistance exceeds a deviation range of the preset resistance value, inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested.

[0101] The preset resistance value may be a theoretical value or an empirical value of the resistance when there is no offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested, which is estimated by calculation according to the process conditions. The deviation range of the preset resistance value may be a deviation range of the resistance that does not affect the electrical properties of the first metal line 1 to be tested and the second metal line 2 to be tested. That is, the deviation range of the preset resistance value is the allowable range of the actual measured resistance value deviating from the theoretical value or the empirical value of the resistance.

[0102] Step S230 , performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the sections in different directions.

[0103] Step S240, determining the existence of the offset phenomenon and the offset direction according to the microscopic topography image.

[0104] The process of slicing and determining the offset is basically the same as that of the previous embodiment, and therefore, will not be described again here.

[0105] The test method for the alignment offset between metal layers disclosed in the present invention can apply voltage to the first test pad 5 and the second test pad 6 respectively to detect the breakdown voltage between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested; or apply a preset current to flow between the first test pad 5 and the second test pad 6, measure the resistance between the conductive test structure 3 and the first metal line 1 to be tested or the second metal line 2 to be tested, compare the breakdown voltage or resistance with the preset voltage value or the preset resistance value, and infer that there is an offset phenomenon between the first metal line 1 to be tested and the second metal line 2 to be tested when the breakdown voltage or resistance exceeds the preset deviation range of the preset voltage value or the preset resistance value, and the offset direction between the second metal line 2 to be tested and the first metal line 1 to be tested can be further determined by sectioning. That is, in the present invention, through a semiconductor test structure, it is possible to detect whether there is an overlay shift phenomenon between the upper and lower metal lines, and determine the specific direction of the offset, provide a window reference for metal layer offset (overlay shift) for the improvement of semiconductor technology, monitor the process, and help improve process reliability. When the breakdown voltage or resistance does not exceed the preset deviation range of the preset voltage value or the preset resistance value, it can be directly determined that there is no offset between the first metal line 1 to be tested and the second metal line 2 to be tested, and there is no need for further sectioning, which has a high test efficiency.

[0106] It should be noted that, although the steps of the method for testing the alignment offset between metal layers in the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0107] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A semiconductor test structure, characterized in that: include: A first metal layer to be tested and a second metal layer to be tested are stacked and distributed, the first metal layer to be tested and the second metal layer to be tested are filled with an interlayer dielectric layer, the first metal layer to be tested includes first metal lines to be tested with equal line widths, and the second metal layer to be tested includes second metal lines to be tested with equal line widths; A conductive test structure, comprising a first conductive test section and / or a second conductive test section, wherein the first conductive test section is distributed in the same layer as the first metal layer to be tested, and the second conductive test section is distributed in the same layer as the second metal layer to be tested; wherein the first conductive test section has a uniform line width at each location, and the second conductive test section also has a uniform line width at each location; the first conductive test section is uniformly spaced from the first metal line to be tested, and the second conductive test section is uniformly spaced from the second metal line to be tested; The first metal line to be tested is connected to the second metal line to be tested via a plurality of vias, and the vias penetrate the interlayer dielectric layer; A first test pad connected to the first conductive test portion or the second conductive test portion; The second test pad is connected to the first metal line to be tested or the second metal line to be tested.

2. The semiconductor test structure according to claim 1, characterized in that: The first metal line to be tested is a serpentine structure, and the serpentine structure corresponding to the first metal line to be tested is used as a first serpentine structure, one side of the first serpentine structure has a plurality of first grooves distributed at intervals, and the other side has a plurality of second grooves distributed at intervals, and the plurality of first grooves and the plurality of second grooves are alternately distributed; The second metal line to be tested is also a serpentine structure, and the serpentine structure corresponding to the second metal line to be tested is used as a second serpentine structure, one side of the second serpentine structure has a plurality of third grooves distributed at intervals, and the other side has a plurality of fourth grooves distributed at intervals, and the plurality of third grooves and the plurality of fourth grooves are alternately distributed; The first conductive testing part comprises a first comb-shaped structure and a second comb-shaped structure, wherein the first comb-shaped structure is disposed on one side of the first serpentine structure, and each comb tooth of the first comb-shaped structure is correspondingly inserted into a different first groove; The second comb-shaped structure is placed on the other side of the first serpentine structure, and each comb tooth of the second comb-shaped structure is correspondingly inserted into a different second groove; The second conductive testing part includes a third comb structure and a fourth comb structure, wherein the third comb structure is placed on one side of the second serpentine structure, and each comb tooth of the third comb structure is respectively inserted into a different third groove; the fourth comb structure is placed on the other side of the second serpentine structure, and each comb tooth of the fourth comb structure is respectively inserted into a different fourth groove.

3. The semiconductor test structure according to claim 2, characterized in that: The conductive test structure includes the first conductive test portion, and the first test pad is connected to the first conductive test portion; or the conductive test structure includes the second conductive test portion, and the first test pad is connected to the second conductive test portion; The first serpentine structure and the second serpentine structure are connected via a plurality of vias, and the second test pad is connected to the first serpentine structure or the second serpentine structure.

4. The semiconductor test structure according to claim 3, characterized in that: The conductive test structure includes the first conductive test portion, and the first test pad is connected to the first comb-shaped structure or the second comb-shaped structure.

5. The semiconductor test structure according to claim 3, characterized in that: The conductive test structure includes the second conductive test portion, and the first test pad is connected to the third comb-shaped structure or the fourth comb-shaped structure.

6. The semiconductor test structure according to claim 2, characterized in that: The first test pad is connected to any one of the first comb structure, the second comb structure, the third comb structure and the fourth comb structure, and the second test pad is connected to the first serpentine structure or the second serpentine structure.

7. The semiconductor test structure according to claim 1, characterized in that: The first metal wire to be tested includes a plurality of first comb-shaped structures interconnected with each other, the first comb-shaped structures including a first comb spine and a plurality of first comb teeth located on one side or both sides of the first comb spine, and the plurality of first comb teeth and the first comb spine form a plurality of first tooth gaps distributed at intervals; The second metal wire to be tested includes a plurality of second comb-shaped structures interconnected with each other, the second comb-shaped structures include a second comb spine and a plurality of second comb teeth located on one side or both sides of the second comb spine, and the plurality of second comb teeth and the second comb spine form a plurality of second tooth gaps distributed at intervals; The first conductive testing part comprises a third comb-shaped structure, and each comb tooth of the third comb-shaped structure is respectively inserted into a different first tooth gap; The second conductive testing portion includes a fourth comb-shaped structure, and each comb tooth of the fourth comb-shaped structure is correspondingly inserted into a different second tooth gap.

8. The semiconductor test structure according to claim 7, wherein the conductive test structure comprises the first conductive test portion, and the first test pad is connected to the first conductive test portion; or the conductive test structure comprises the second conductive test portion, and the first test pad is connected to the second conductive test portion; characterized in that: The first comb-shaped structure and the second comb-shaped structure are connected via a plurality of vias, and the second test pad is connected to the first comb-shaped structure or the second comb-shaped structure.

9. The semiconductor test structure according to claim 8, characterized in that: The conductive test structure includes the first conductive test portion, and the first test pad is connected to the third comb-shaped structure.

10. The semiconductor test structure according to claim 8, characterized in that: The conductive test structure includes the second conductive test portion, and the first test pad is connected to the fourth comb-shaped structure.

11. The semiconductor test structure according to claim 7, characterized in that: The conductive test structure includes the first conductive test portion and the second conductive test portion, and the first comb-shaped structure and the second comb-shaped structure are connected through a plurality of vias.

12. The semiconductor test structure according to claim 11, characterized in that: The first test pad is connected to the third comb-type structure or the fourth comb-type structure, and the second test pad is connected to the first comb-type structure or the second comb-type structure.

13. The semiconductor test structure according to claim 1, characterized in that: The first conductive test part is a serpentine structure, and the serpentine structure corresponding to the first conductive test part is used as a third serpentine structure, one side of the third serpentine structure has a plurality of first recesses distributed at intervals, and the other side has a plurality of second recesses distributed at intervals, and the plurality of first recesses and the plurality of second recesses are alternately distributed; The second conductive test portion is also a serpentine structure, and the serpentine structure corresponding to the second conductive test portion is used as a fourth serpentine structure, one side of the fourth serpentine structure has a plurality of third recesses distributed at intervals, and the other side has a plurality of fourth recesses distributed at intervals, and the plurality of third recesses and the plurality of fourth recesses are alternately distributed; The first metal line to be tested includes a fifth comb-shaped structure and a sixth comb-shaped structure, wherein the fifth comb-shaped structure is disposed on one side of the third serpentine structure, and each comb tooth of the fifth comb-shaped structure is correspondingly inserted into a different first recess; The sixth comb-shaped structure is placed on the other side of the third serpentine structure, and each comb tooth of the sixth comb-shaped structure is correspondingly inserted into a different second recess; The second metal line to be tested includes a seventh comb structure and an eighth comb structure, wherein the seventh comb structure is placed on one side of the fourth serpentine structure, and each comb tooth of the seventh comb structure is respectively inserted into a different third recess; the eighth comb structure is placed on the other side of the fourth serpentine structure, and each comb tooth of the eighth comb structure is respectively inserted into a different fourth recess.

14. The semiconductor test structure according to claim 13, characterized in that: The conductive test structure includes the first conductive test part, and the first test pad is connected to the first conductive test part; or the conductive test structure includes the second conductive test part, and the first test pad is connected to the second conductive test part; or the conductive test structure includes the first conductive test part and the second conductive test part, and the first test pad is connected to the first conductive test part or the second conductive test part; The fifth comb structure is connected to the seventh comb structure through a plurality of vias, the sixth comb structure is connected to the eighth comb structure through a plurality of vias, and the second test pad is connected to any one of the fifth comb structure, the sixth comb structure, the seventh comb structure or the eighth comb structure.

15. A method for testing metal layer alignment deviation, characterized in that: The testing method uses the semiconductor testing structure according to any one of claims 1 to 14 for testing, and the testing method comprises: Detecting a breakdown voltage between the first metal line to be tested and the first conductive test portion; or detecting a breakdown voltage between the second metal line to be tested and the second conductive test portion; Comparing the breakdown voltage with a preset voltage value, and inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested when the breakdown voltage exceeds a preset deviation range of the preset voltage value; Performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the cross sections in different directions; The existence of the offset phenomenon is determined based on the microscopic morphology image, and the offset direction is determined.

16. The method for testing metal layer alignment deviation according to claim 15, characterized in that: Detecting the breakdown voltage between the first metal line to be tested and the first conductive test part, the detection process includes: applying a first voltage and a second voltage to the first test pad and the second test pad respectively, when the first metal line to be tested and the first conductive test part are broken down, the voltage difference between the first voltage and the second voltage is the breakdown voltage.

17. The method for testing metal layer alignment deviation according to claim 15, characterized in that: Detecting the breakdown voltage between the second metal line to be tested and the second conductive test part, the detection process includes: applying a first voltage and a second voltage to the first test pad and the second test pad respectively, when the second metal line to be tested and the second conductive test part are broken down, the voltage difference between the first voltage and the second voltage is the breakdown voltage.

18. A method for testing metal layer alignment deviation, characterized in that: The testing method uses the semiconductor testing structure according to any one of claims 1 to 14 for testing; the testing method comprises: Measuring the resistance between the first metal line to be tested and the first conductive test portion; or measuring the resistance between the second metal line to be tested and the second conductive test portion; comparing the resistance with a preset resistance value, and inferring that there is an offset phenomenon between the first metal line to be tested and the second metal line to be tested when the resistance exceeds a preset deviation range of the preset resistance value; Performing sectioning processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at the cross sections in different directions; The existence of the offset phenomenon is determined based on the microscopic morphology image, and the offset direction is determined.

19. The method for testing metal layer alignment deviation according to claim 18, characterized in that: The resistance between the first metal line to be tested and the first conductive test part is measured, and the measurement process includes: applying a preset current to flow between the first test pad and the second test pad, and measuring the voltage difference between the first metal line to be tested and the first conductive test part, and the resistance is equal to the ratio of the voltage difference to the preset current.

20. The method for testing metal layer alignment deviation according to claim 18, characterized in that: Measure the resistance between the second metal line to be tested and the second conductive test part, the measurement process includes: applying a preset current to flow between the first test pad and the second test pad, measuring the voltage difference between the second metal line to be tested and the second conductive test part, and the resistance is equal to the ratio of the voltage difference to the preset current.

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