Semiconductor test structure and metal layer alignment deviation test method

Abstract

The present disclosure provides a semiconductor test structure and a test method for alignment offset between metal layers, and relates to the field of semiconductors. The test structure includes a first metal line to be tested and a second metal line to be tested, the first metal line to be tested and the second metal line to be tested are stacked and distributed, the conductive test structure includes a first conductive test part and / or a second conductive test part, the first conductive test part is distributed in the same layer as the first metal layer to be tested, and the second conductive test part is distributed in the same layer as the second metal layer to be tested; the first conductive test part has the same line width at all locations, and the second conductive test part also has the same line width at all locations; the spacing between the first conductive test part and the first metal line to be tested is equal at all locations, and the spacing between the second conductive test part and the second metal line to be tested is equal at all locations; the first metal line to be tested and the second metal line to be tested are connected through a via; a first test pad is connected to the first conductive test part or the second conductive test part; and a second test pad is connected to the first metal line to be tested or the second metal line to be tested.

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 devices are widely used in mobile devices such as mobile phones and tablets due to their small size, high integration, and fast transmission speeds. During the semiconductor manufacturing process, factors such as the manufacturing process can cause occasional misalignment between the upper and lower conductive layers of a conductive pillar, which can affect device electrical performance. Therefore, it is necessary to monitor this misalignment during the manufacturing process to assess process reliability.

[0003] However, when performing breakdown voltage testing and detecting whether there is metal layer overlay shift, existing test structures need to be used to detect shifts in different directions, resulting in more test structures and a larger area occupied by the test structures 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 prior art known to ordinary technicians in the field. Summary of the Invention

[0005] The present disclosure provides a method for testing semiconductor test structures and 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:

[0007] A first metal layer to be tested and a second metal layer to be tested are stacked and distributed, an interlayer dielectric layer is filled between the first metal layer to be tested and the second metal layer to be tested, the first metal layer to be tested includes first metal lines to be tested with equal line width, and the second metal layer to be tested includes second metal lines to be tested with equal line width;

[0008] A conductive test structure includes a first conductive test portion and / or a second conductive test portion, wherein the first conductive test portion is co-located with the first metal layer to be tested, and the second conductive test portion is co-located with the second metal layer to be tested; wherein the first conductive test portion has a uniform line width at all locations, and the second conductive test portion also has a uniform line width at all locations; the first conductive test portion is uniformly spaced from the first metal line to be tested, and the second conductive test portion is uniformly spaced from the second metal line to be tested;

[0009] The first metal line to be tested and the second metal line to be tested are connected via a plurality of vias, and the vias penetrate the interlayer dielectric layer;

[0010] a first test pad connected to the first conductive test portion or the second conductive test portion;

[0011] The second test pad is connected to the first metal line to be tested or the second metal line to be tested.

[0012] 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.

[0013] The second metal line to be tested also has a serpentine structure, and the serpentine structure corresponding to the second metal line to be tested is used as a second serpentine structure, wherein 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;

[0014] The first conductive testing portion includes a first comb structure and a second comb structure, wherein the first comb structure is placed on one side of the first serpentine structure, and each comb tooth of the first comb structure is respectively inserted into a different first groove; the second comb structure is placed on the other side of the first serpentine structure, and each comb tooth of the second comb structure is respectively inserted into a different second groove;

[0015] 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.

[0016] 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;

[0017] The first serpentine structure and the second serpentine structure are connected through a plurality of vias, and the second test pad is connected to the first serpentine structure or the second serpentine structure.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] In an exemplary embodiment of the present disclosure, the first metal wire to be tested includes a plurality of interconnected first comb-shaped structures, 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, the plurality of first comb teeth and the first comb spine forming a plurality of first tooth gaps distributed at intervals;

[0022] The second metal wire to be tested includes a plurality of second comb-shaped structures interconnected with each other, the second comb-shaped structures including a second comb ridge and a plurality of second comb teeth located on one side or both sides of the second comb ridge, the plurality of second comb teeth and the second comb ridge forming a plurality of second tooth gaps distributed at intervals;

[0023] The first conductive testing portion includes a third comb-shaped structure, and each comb tooth of the third comb-shaped structure is correspondingly inserted into a different first tooth gap;

[0024] 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.

[0025] 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.

[0026] 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-shaped structure.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The second conductive testing portion also has a serpentine structure. The serpentine structure corresponding to the second conductive testing 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. The plurality of third recesses and the plurality of fourth recesses are alternately distributed.

[0032] 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 respectively 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 respectively inserted into a different second recess;

[0033] 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.

[0034] 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;

[0035] 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.

[0036] According to one aspect of the present disclosure, a method for testing alignment deviation between metal layers is provided. The method is performed using any one of the semiconductor test structures described above. The method comprises:

[0037] 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;

[0038] comparing the breakdown voltage with a preset voltage value, and inferring that an offset phenomenon exists 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;

[0039] Performing cross-section processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at cross-sections in different directions;

[0040] The existence of the offset phenomenon is determined based on the microscopic topography, and the offset direction is determined.

[0041] 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.

[0042] In an exemplary embodiment of the present disclosure, the 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 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.

[0043] According to one aspect of the present disclosure, a method for testing alignment deviation between metal layers is provided. The method uses any one of the semiconductor test structures described above for testing. The method comprises:

[0044] measuring the resistance between the first metal wire to be tested and the first conductive test portion; or measuring the resistance between the second metal wire to be tested and the second conductive test portion;

[0045] comparing the resistance with a preset resistance value, and inferring that an offset phenomenon exists between the first metal wire to be tested and the second metal wire to be tested when the resistance exceeds a preset deviation range of the preset resistance value;

[0046] Performing cross-section processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at cross-sections in different directions;

[0047] The existence of the offset phenomenon is determined based on the microscopic topography, and the offset direction is determined.

[0048] 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.

[0049] 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.

[0050] The semiconductor test structure and the method for testing alignment shift between metal layers disclosed herein can apply voltages to a first test pad and a second test pad, respectively, to detect a 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 between the first test pad and the second test pad to measure the resistance between the conductive test structure and the first metal line to be tested or the second metal line to be tested, and compare the breakdown voltage or resistance with a preset voltage value or a preset resistance value. When the breakdown voltage or resistance exceeds a 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 to be tested and the second metal line to be tested, 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, the present disclosure uses a semiconductor test structure to detect whether there is an overlay shift phenomenon between upper and lower metal lines, and to determine the specific direction of the offset, providing a window reference for metal layer overlay shift for improving semiconductor processes and monitoring the process, thereby helping to improve process reliability. Due to the limited placement area for test structures (Testkey), the number of semiconductor test structures that can be placed in the present disclosure is reduced. Compared to the existing solution of placing two different test structures to detect two different directional offsets (overlay shift), the present disclosure proposes using a single test structure to detect both directions simultaneously. This can save the placement area of the semiconductor test structure and reduce manufacturing costs. It can also save test time and test times, thereby improving test efficiency. In addition, when the breakdown voltage or resistance does not exceed the preset deviation range of the preset voltage value or preset resistance value, it can be directly determined that there is no offset between the first metal line to be tested and the second metal line to be tested, without the need for further sectioning, resulting in higher test efficiency.

[0051] 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 disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are incorporated into 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 drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0053] Figure 1 FIG. 1 is a schematic diagram of a semiconductor test structure according to an embodiment of the present disclosure.

[0054] Figure 2 FIG. 1 is a schematic diagram of a first metal line to be tested and a first conductive testing portion in one embodiment of the present disclosure.

[0055] Figure 3 FIG. 1 is a schematic diagram of a semiconductor test structure in which the conductive test structure includes only the first conductive test portion in an embodiment of the present disclosure.

[0056] Figure 4 FIG. 1 is a schematic diagram of a semiconductor test structure in which the conductive test structure includes only the second conductive test portion in an embodiment of the present disclosure.

[0057] Figure 5 Schematic diagram of a semiconductor test structure in which the conductive test structure includes only the first conductive test portion and the width of the first metal line to be tested is greater than the width of the second metal line to be tested in an embodiment of the present disclosure.

[0058] Figure 6 Schematic diagram of a semiconductor test structure in which the conductive test structure includes only the first conductive test portion and the width of the first metal line to be tested is smaller than the width of the second metal line to be tested in an embodiment of the present disclosure.

[0059] Figure 7 Schematic diagram of a semiconductor test structure in which the conductive test structure includes only the second conductive test portion and the width of the first metal line to be tested is greater than the width of the second metal line to be tested in an embodiment of the present disclosure.

[0060] Figure 8 Schematic diagram of a semiconductor test structure in which the conductive test structure includes only the second conductive test portion and the width of the first metal line to be tested is smaller than the width of the second metal line to be tested in an embodiment of the present disclosure.

[0061] Figure 9 FIG. 1 is a schematic diagram of a semiconductor test structure according to an embodiment of the present disclosure.

[0062] Figure 10 FIG. 1 is a schematic diagram of a semiconductor test structure according to an embodiment of the present disclosure.

[0063] Figure 11 1 is a top view of a first metal line to be tested, a second metal line to be tested, a first conductive testing portion, and a second conductive testing portion in one embodiment of the present disclosure.

[0064] Figure 12 FIG. 1 is a schematic diagram of a semiconductor test structure according to an embodiment of the present disclosure.

[0065] Figure 13 Schematic diagram of a method for testing alignment deviation between metal layers in one embodiment of the present disclosure.

[0066] Figure 14 Schematic diagram of a method for testing alignment deviation between metal layers in another embodiment of the present disclosure.

[0067] Description of reference numerals:

[0068] 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 the fifth comb structure; 14. Sixth comb-shaped structure; 141. Comb teeth of the sixth comb structure; 15. Seventh comb structure; 151. Comb teeth of the seventh comb structure; 16. Eighth comb structure; 161. Comb teeth of the eighth comb structure; 2. Second metal line to be tested; 201. Third groove; 202. Fourth groove; 3. Conductive test structure; 31. First conductive test structure Test portion; 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 portion; 303, third recess; 304, fourth recess; 321, third comb-like structure; 3211, comb teeth of the third comb structure; 322, fourth comb structure; 3221, comb teeth of the fourth comb structure; 4, via; 5, first test pad; 6, second test pad. DETAILED DESCRIPTION

[0069] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent identical or similar structures, and thus their detailed descriptions will be omitted. Furthermore, the figures are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0070] Although relative terms such as "upper" and "lower" are used in this specification to describe the relationship of one illustrated component to another, these terms are used herein for convenience only, such as in accordance with the orientation of the illustrations in the accompanying drawings. It will be understood that if the illustrated device were flipped upside down, the component described as "upper" would become the component "lower." When a structure is referred to as "on" another structure, this may mean that the structure is integrally formed with the other structure, that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure via the other structure.

[0071] 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 open-ended inclusion and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.; the terms "first", "second"... "eighth", etc. are used only as labels and are not intended to limit the quantity of their objects.

[0072] In the semiconductor manufacturing industry, reliability testing is a critical step in ensuring product process stability and reliability. This process typically relies on various test structures designed on the wafer to evaluate and verify performance under different conditions. Breakdown voltage (or resistance) is a key indicator of dielectric insulation performance and is crucial for evaluating the withstand voltage capability of semiconductor devices.

[0073] In the design of traditional breakdown voltage test structures, the metal layer groups on the upper and lower sides of the dielectric layer are usually designed independently, and in order to meet 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 test structures are placed in the cutting path between two adjacent chips on the wafer and used as process monitoring structures. The location 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-hole, 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.

[0074] Currently, test structures aligned in the same direction across the metal layer exhibit a single-dimensional nature when detecting overlay offset, meaning they can only detect offsets in a specific direction. To comprehensively assess offset, multiple test structures with different orientations are typically required, which increases test complexity, occupies more wafer area, and reduces test efficiency.

[0075] 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:

[0076] A first metal layer to be tested and a second metal layer to be tested are stacked and arranged, an interlayer dielectric layer is filled between the first metal layer to be tested and the second metal layer to be tested, 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;

[0077] The conductive test structure 3 includes a first conductive test portion 31 and / or a second conductive test portion 32. The first conductive test portion 31 is co-located with the first metal layer to be tested, and the second conductive test portion 32 is co-located with the second metal layer to be tested. The first conductive test portion 31 has a uniform line width, and the second conductive test portion 32 also has a uniform line width. The first conductive test portion 31 is uniformly spaced from the first metal line 1 to be tested, and the second conductive test portion 32 is uniformly spaced from the second metal line 2 to be tested.

[0078] The first metal line to be tested 1 is connected to the second metal line to be tested 2 via a plurality of vias 4, and the vias 4 penetrate the interlayer dielectric layer (not shown in the figure);

[0079] The first test pad 5 is connected to the first conductive test portion 31 or the second conductive test portion 32;

[0080] 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.

[0081] The semiconductor test structure disclosed herein 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 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 compare the breakdown voltage or resistance 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 can be further determined by sectioning. That is, in the present disclosure, 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 for test structures (Testkey), the number of semiconductor test structures that can be placed in the present disclosure is reduced. Compared to the existing solution of placing two different test structures to detect two different directional offsets (overlay shift), the present disclosure proposes using a single test structure to detect both directions simultaneously. This can save the placement area of the semiconductor test structure and reduce manufacturing costs. It can also save test time and the number of tests, thereby improving 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 between the first metal line 1 to be tested and the second metal line 2 to be tested, without the need for further sectioning, and the test efficiency is higher.

[0082] The following describes in detail the various parts and details of the semiconductor test structure disclosed in the present invention:

[0083] 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 space between the first metal layer to be tested and the second metal layer to be tested is 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 uniform throughout, and simultaneously, the line widths of the second metal lines 2 to be tested in the second metal layer to be tested are uniform throughout. The line widths of the first metal lines 1 to be tested and the second metal lines 2 to be tested may be equal or unequal, without any particular limitation herein.

[0084] 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.

[0085] The material of the first metal wire to be tested 1 can be a material with strong electrical conductivity, for example, copper, aluminum, tungsten, or titanium nitride. Of course, other materials with strong electrical conductivity are also possible, and are not listed here. The material of the interlayer dielectric layer can be an insulating material, for example, silicon oxide or silicon nitride. The material of the second metal wire to be tested 2 can also be a material with strong electrical conductivity, for example, copper, aluminum, tungsten, or titanium nitride. Of course, other materials with strong electrical conductivity are also possible, and are not listed here.

[0086] In some embodiments of the present disclosure, Figure 2 As shown, the first metal wire to be tested 1 can have a serpentine structure, an S-shaped structure, or a straight structure. When the first metal wire to be tested 1 has a serpentine structure, in order to facilitate the distinction between the first metal wire to be tested 1 and the second metal wire to be tested 2, the serpentine structure corresponding to the first metal wire to be tested 1 can be used as the first serpentine structure. One side of the first serpentine structure has a plurality of first grooves 101 spaced apart, and the other side has a plurality of second grooves 102 spaced apart. The plurality of first grooves 101 and the plurality of second grooves 102 are alternately distributed. It should be noted that the first grooves 101 and the second grooves 102 are groove-like structures defined by the structure of the first serpentine structure itself.

[0087] Please continue to see Figure 1As shown, the structure of the second metal wire 2 to be tested can also be a serpentine structure, an S-shaped structure, or a straight structure. In this disclosure, the second metal wire 2 to be tested is taken as an example of a serpentine structure to illustrate its setting details and the coordination relationship with other structures. For ease of distinction, the serpentine structure corresponding to the second metal wire 2 to be tested can be referred to as a second serpentine structure. One side of the second serpentine structure has a plurality of spaced third grooves 201, and the other side has a plurality of spaced fourth grooves 202. The plurality of third grooves 201 and the plurality of fourth grooves 202 are alternately distributed. It should be noted that the third grooves 201 and the fourth grooves 202 are groove-like structures defined by the structure of the second serpentine structure itself.

[0088] 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 via a plurality of vias 4. The vias 4 can penetrate the interlayer dielectric layer and are filled with a conductive material. That is, the conductive material can connect the first metal line 1 to the second metal line 2 to be tested. 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 the conductive characteristics of the vias 4.

[0089] 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, which 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, that is, the line width of each area in the first conductive test portion 31 is equal; and the spacing between the first conductive test portion 31 and the first metal line 1 to be tested is equal (that is, Figure 2 (a=b=c=d). It should be noted that the line width of the first conductive test portion 31 follows the minimum design rule, meaning that the line width of the first conductive test portion 31 is the minimum line width that satisfies its inherent conductive properties. The spacing between the first conductive test portion 31 and the first metal line to be tested 1 is the minimum spacing that ensures that there is no conduction or coupling between the two.

[0090] 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 straight, the first conductive test portion 31 is also straight; when the shape of the first metal line 1 to be tested is serpentine or S-shaped, the first conductive test portion 31 is a comb-like structure (such as Figure 1-Figure 3 shown).

[0091] In other embodiments of the present disclosure, Figure 4As 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 the same line width everywhere, that is, the line width of each area in the second conductive test portion 32 is 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 with each other.

[0092] 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 straight, the second conductive test portion 32 is also straight; when the shape of the second metal line 2 to be tested is serpentine or S-shaped, the second conductive test portion 32 is a comb-like structure (such as Figure 1 and Figure 4 shown).

[0093] In some further embodiments of the present disclosure, please continue to refer to Figure 1 As shown, the conductive test structure 3 may include a first conductive test portion 31 and a second conductive test portion 32. The first conductive test portion 31 is co-located with the first metal layer to be tested, while the second conductive test portion 32 is co-located with the second metal layer to be tested. The first conductive test portion 31 has a uniform line width, as does the second conductive test portion 32. The spacing between the first conductive test portion 31 and the first metal line 1 to be tested is uniform, while the spacing between the second conductive test portion 32 and the second metal line 2 to be tested is uniform.

[0094] 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 portion 31 may include a first comb structure 311 and a second comb structure 312, wherein the first comb structure 311 is placed on one side of the first serpentine structure, the number of comb teeth 3111 of the first comb structure matches the number of first grooves 101, and the comb teeth 3111 of the first comb structure are respectively inserted into different first grooves 101, and the spacing between all areas of the comb teeth 3111 of the first comb structure and the surrounding first metal line 1 to be tested is equal. The second comb structure 312 is placed on the other side of the first serpentine structure, the number of comb teeth 3121 of the second comb structure matches the number of second grooves 102, and the comb teeth 3121 of the second comb structure are respectively inserted into different second grooves 102, and the spacing between all areas of the comb teeth 3121 of the second comb structure and the surrounding first metal line 1 to be tested is equal.

[0095] 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 portion 32 may include a third comb structure 321 and a fourth comb structure 322, wherein the third comb structure 321 is placed on one side of the second serpentine structure, the number of comb teeth 3211 of the third comb structure matches the number of third grooves 201, and the comb teeth 3211 of the third comb structure are respectively inserted into different third grooves 201, and the spacing between all areas of the comb teeth 3211 of the third comb structure and the surrounding second metal line 2 to be tested is equal. The fourth comb structure 322 is placed on the other side of the second serpentine structure, the number of comb teeth 3221 of the fourth comb structure matches the number of fourth grooves 202, and the comb teeth 3221 of the fourth comb structure are respectively inserted into different fourth grooves 202, and the spacing between all areas of the comb teeth 3221 of the fourth comb structure and the surrounding second metal line 2 to be tested is equal.

[0096] Please continue to see Figure 1 、 Figure 3 and Figure 4 As shown, the first test pad 5 can be in sheet form and made of a conductive material, for example, copper. The first test pad 5 can 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 includes only 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 to the connection area between the first test pad 5 and the first conductive test part 31.

[0097] 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 structure 321 in the second conductive test part 32, or connected to the fourth comb structure 322 in the second conductive test part 32. No special limitation is made to the connection area between the first test pad 5 and the second conductive test part 32.

[0098] When the conductive test structure 3 includes both the first conductive test section 31 and the second conductive test section 32, the first serpentine structure and the second serpentine structure can be connected through multiple vias 4. The first test pad 5 can be connected to the first conductive test section 31 or the second conductive test section 32. For example, the first test pad 5 can be connected to any one of the first comb structure 311, the second comb structure 312, the third comb structure 321, and the fourth comb structure 322.

[0099] Please continue to see Figure 1 、 Figure 3 and Figure 4 As shown, the second test pad 6 can also be in the form of a sheet, and its material can be a conductive material, for example, its material can be copper. The second test pad 6 can be connected to the end of the first metal line to be tested 1 or the end of the second metal line to be tested 2. For example, the second test pad 6 can be connected to the first serpentine structure or the second serpentine structure. Voltage can 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 to be tested 1 or the second metal line to be tested 2; or a preset current can 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 to be tested 1 or the second metal line to be tested 2, and the breakdown voltage or resistance is 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 to be tested 1 and the second metal line to be tested 2, and the offset direction between the second metal line to be tested 2 and the first metal line to be tested 1 can be further determined by sectioning.

[0100] 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.

[0101] In an exemplary embodiment of the present disclosure, when the line widths of the first metal line to be tested 1 and the second metal line to be tested 2 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 to be tested 1 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 to be tested 2.

[0102] In some embodiments of the present disclosure, Figure 5As 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 7 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 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. In some embodiments of the present disclosure, as 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.

[0103] In an exemplary embodiment of the present disclosure, when the line widths of the first metal line to be tested 1 and the second metal line to be tested 2 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. Figure 9 As shown, when the line width of the first metal line to be tested 1 is greater than the line width of the second metal line to be tested 2, the line width of the first conductive test portion 31 is equal to the line width of the first metal line to be tested 1; the line width of the second conductive test portion 32 is greater than the line width of the second metal line to be tested 2, 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 to be tested 1 (i.e. Figure 9 twice of 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 (ie Figure 9 f), and then subtract the line width of the second metal line 2 to be tested. Figure 10 As shown, when the line width of the first metal line to be tested 1 is smaller than the line width of the second metal line to be tested 2, the line width of the second conductive test portion 32 is equal to the line width of the second metal line to be tested 2; the line width of the first conductive test portion 31 is larger than the line width of the first metal line to be tested 1, 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 to be tested 2 (i.e. Figure 10g) minus the distance between the center line of the first conductive test portion 31 and the center line of the first metal wire 1 to be tested (i.e. Figure 10 h), and then subtract the line width of the first metal line 1 to be tested.

[0104] In an exemplary embodiment of the present disclosure, Figure 11 As 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 conductive test structure 3 (e.g., the first conductive test portion 31 or the second conductive test portion 32) can be a serpentine structure, and accordingly, 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-like structure.

[0105] In an exemplary embodiment of the present disclosure, the first conductive testing portion 31 may have a serpentine structure. The serpentine structure corresponding to the first conductive testing portion 31 may serve as a third serpentine structure. One side of the third serpentine structure has a plurality of first recesses 301 spaced apart, and the other side has a plurality of second recesses 302 spaced apart. 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-like structures defined by the structure of the third serpentine structure itself.

[0106] In some embodiments of the present disclosure, please continue to refer to Figure 11 As shown, when the first conductive test portion 31 is a serpentine structure, the first metal line 1 to be tested in the first metal layer to be tested includes two metal lines, both of which are comb-shaped structures. For ease of distinction, the first metal line 1 to be tested can be defined as including a fifth comb structure 13 and a sixth comb structure 14, wherein the fifth comb structure 13 is placed on one side of the third serpentine structure, the number of comb teeth 131 of the fifth comb structure matches the number of first recesses 301, the comb teeth 131 of the fifth comb structure are respectively inserted into different first recesses 301, and all areas of the comb teeth 131 of the fifth comb structure are spaced equal to the surrounding first conductive test portion 31; the sixth comb structure 14 is placed on the other side of the third serpentine structure, the number of comb teeth 141 of the sixth comb structure matches the number of second recesses 302, and the comb teeth 141 of the sixth comb structure are respectively inserted into different second recesses 302, and all areas of the comb teeth 141 of the sixth comb structure are spaced equal to the surrounding first conductive test portion 31.

[0107] In some embodiments of the present disclosure, please continue to refer to Figure 11As shown, the second conductive testing portion 32 may also have a serpentine structure. The serpentine structure corresponding to the second conductive testing portion 32 may be used as a fourth serpentine structure. One side of the fourth serpentine structure has a plurality of spaced third recesses 303, and the other side has a plurality of spaced fourth recesses 304. 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-like structures defined by the structure of the fourth serpentine structure itself.

[0108] In some embodiments of the present disclosure, when the second conductive test portion 32 is a serpentine structure, the second metal line 2 to be tested in the first metal layer to be tested includes two metal lines, both of which are comb-shaped structures. For ease of distinction, the second metal line 2 to be tested can be defined as including a seventh comb structure 15 and an eighth comb structure 16, wherein the seventh comb structure 15 is placed on one side of the third serpentine structure, the number of comb teeth 151 of the seventh comb structure matches the number of third recesses 303, the comb teeth 151 of the seventh comb structure are respectively inserted into different third recesses 303, and all areas of the comb teeth 151 of the seventh comb structure are spaced equal to the second conductive test portion 32 around them; the eighth comb structure 16 is placed on the other side of the third serpentine structure, the number of comb teeth 161 of the eighth comb structure matches the number of fourth recesses 304, and the comb teeth 161 of the eighth comb structure are respectively inserted into different fourth recesses 304, and all areas of the comb teeth 161 of the eighth comb structure are spaced equal to the second conductive test portion 32 around them.

[0109] In some embodiments of the present disclosure, 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. In this case, the fifth comb structure 13 and the seventh comb structure 15 are connected via multiple vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected via multiple vias 4, and the second test pad 6 is connected to any one of the fifth comb structure 13, the sixth comb structure 14, the seventh comb structure 15, or the eighth comb structure 16.

[0110] 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. In this case, the fifth comb structure 13 and the seventh comb structure 15 are connected via multiple vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected via multiple vias 4, and the second test pad 6 is connected to any one of the fifth comb structure 13, the sixth comb structure 14, the seventh comb structure 15, or the eighth comb structure 16.

[0111] In some embodiments of the present disclosure, when the conductive test structure 3 includes both the first conductive test portion 31 and the second conductive test portion 32, the first test pad 5 is connected to either the first conductive test portion 31 or the second conductive test portion 32. In this case, the fifth comb structure 13 and the seventh comb structure 15 are connected via multiple vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected via multiple vias 4, and the second test pad 6 is connected to any one of the fifth comb structure 13, the sixth comb structure 14, the seventh comb structure 15, or the eighth comb structure 16.

[0112] In an exemplary embodiment of the present disclosure, Figure 12 As shown, the first metal wire to be tested 1 may include multiple interconnected first comb-type structures 11, each of which includes a first comb spine 111 and multiple first comb teeth 112 located on one side or both sides of the first comb spine 111. The first comb teeth 112 may be distributed in parallel, and the multiple first comb teeth 112 and the first comb spine 111 may form multiple first tooth gaps 113 spaced apart along the length of the first comb spine 111. The ends of the multiple first comb spines 111 in the multiple first comb-type structures 11 located on the same side may be connected together via a first connecting line 12.

[0113] The second metal wire to be tested 2 may include multiple interconnected second comb-type structures (not shown in the figure). The second comb-type structures include a second comb spine and multiple second comb teeth located on one or both sides of the second comb spine. The second comb teeth may be arranged in parallel, and the multiple second comb teeth and the second comb spine may form multiple second tooth gaps spaced apart along the length of the second comb spine. Ends of multiple second comb spines in the multiple second comb-type structures located on the same side may be connected together via a second connecting wire.

[0114] Please continue to see Figure 12 As shown, the first conductive testing portion 31 may include a plurality of interconnected third comb-shaped structures 313. The third comb-shaped structures 313 include a third comb ridge 3131 and a plurality of third comb teeth 3132 located on one or both sides of the third comb ridge 3131. The plurality of third comb teeth 3132 may be spaced apart along the length of the third comb ridge 3131. Each third comb tooth 3132 in the third comb-shaped structure 313 may be inserted into a corresponding first tooth gap 113. The ends of the plurality of third comb ridges 3131 in the plurality of third comb-shaped structures 313 located on the same side may be connected together via a third connecting line 314, and the third connecting line 314 and the first connecting line 12 may be located on a different side.

[0115] The second conductive testing section 32 may include a plurality of interconnected fourth comb-type structures, each comprising a fourth comb spine and a plurality of fourth comb teeth located on one or both sides of the fourth comb spine. The plurality of fourth comb teeth may be spaced apart along the length of the fourth comb spine. Each fourth comb tooth in the fourth comb-type structure may be inserted into a corresponding second tooth gap. Ends of the fourth comb spines in the plurality of fourth comb-type structures located on the same side may be connected together via a fourth connecting line, with the fourth connecting line being located on a different side from the second connecting line.

[0116] In an exemplary embodiment of the present disclosure, the first comb-shaped structure 11 and the second comb-shaped structure can be connected via 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 connecting line 314 in the first conductive test portion 31 that connects the third comb-shaped structures 313.

[0117] When the conductive testing structure 3 includes only the second conductive testing portion 32, the first testing pad 5 is connected to the second conductive testing portion 32. For example, the first testing pad 5 is connected to the fourth comb-shaped structure in the second conductive testing portion 32. For example, the first testing pad 5 is connected to the fourth connecting line connecting each fourth comb-shaped structure in the second conductive testing portion 32.

[0118] In an exemplary embodiment of the present disclosure, the conductive test structure 3 includes not only a first conductive test portion 31 but also a second conductive test portion 32. The first comb-shaped structure 11 and the second comb-shaped structure are connected via a plurality of vias 4. In this case, the first test pad 5 can be connected to the third comb-shaped structure 313, or the first test pad 5 can be connected to the fourth comb-shaped structure.

[0119] The second test pad 6 can be connected to the first comb structure 11 or the second comb structure. For example, the second test pad 6 can be connected to the first connecting line 12 connecting the first comb ridges 111 in each first comb structure 11, or the second test pad 6 can be connected to the second connecting line connecting the second comb ridges in each second comb structure.

[0120] The present disclosure also provides a method for testing the alignment deviation between metal layers, which is performed using the semiconductor test structure in any of the above embodiments. Figure 13 As shown, the testing method may include steps S110 to S140, wherein:

[0121] 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.

[0122] In some embodiments of the present disclosure, the detection process of detecting the breakdown voltage between the first metal line 1 to be tested 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 and the voltage value of the second voltage are different. For example, the first voltage can be a low voltage and the second voltage can be a variable voltage value. The voltage value corresponding to the second voltage can be gradually increased to the second test pad 6 until a breakdown occurs between the first metal line 1 to be tested and the first conductive test part 31. When a breakdown occurs between the first metal line 1 to be tested and the first conductive test part 31, the voltage difference between the first voltage and the second voltage can be used as the breakdown voltage.

[0123] 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 portion 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 portion 32, respectively. The voltage value of the first voltage is different from the voltage value of the second voltage. For example, the first voltage can be a low voltage and the second voltage can be a variable voltage value. The voltage value corresponding to the second voltage can 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 portion 32. When a breakdown occurs between the second metal line 2 to be tested and the second conductive test portion 32, the voltage difference between the first voltage and the second voltage can be used as the breakdown voltage.

[0124] In step S120 , the breakdown voltage is compared with a preset voltage value, and when the breakdown voltage exceeds a preset deviation range of the preset voltage value, it is inferred that there is an offset between the first metal line to be tested and the second metal line to be tested.

[0125] The preset voltage value can be a theoretical value or empirical value of the breakdown voltage when no offset occurs between the first metal line 1 to be tested and the second metal line 2 to be tested, as estimated based on process conditions. The preset deviation range of the preset voltage value can be a deviation range of the breakdown voltage that does not affect the electrical performance of the first metal line 1 to be tested and the second metal line 2 to be tested. In other words, the preset deviation range of the preset voltage value is the allowable range within which the actual measured breakdown voltage value deviates from the theoretical value or empirical value of the breakdown voltage.

[0126] 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.

[0127] The microscopic topography image may be a scanning electron microscope image of the semiconductor test structure.

[0128] Step S140 , determining the presence of the offset phenomenon and the offset direction based on the microscopic topography image.

[0129] Scanning electron microscope images of the semiconductor test structure from different directions can be used to observe whether there is an offset between the first metal layer to be tested and the second metal layer to be tested. If an offset is found between the first metal layer to be tested and the second metal layer to be tested through microscopic morphology analysis, it indicates that the process used to form the first metal layer to be tested and the second metal layer to be tested is defective and needs to be improved. In other words, the design of the semiconductor test structure and the method for testing alignment offset between metal layers disclosed in this disclosure can provide data support for process improvements, helping to improve product yield and product reliability.

[0130] The present disclosure also provides a method for testing the alignment deviation between metal layers, which is performed using the semiconductor test structure in any of the above embodiments. Figure 14 As shown, the testing method may include steps S210 to S240, wherein:

[0131] 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.

[0132] In some embodiments of the present disclosure, the measurement process of measuring the resistance between the first metal wire to be tested 1 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 to be tested 1 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 equal. Correspondingly, the measurement process of measuring the resistance between the second metal wire to be tested 2 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 to be tested 2 and the second conductive test part 32, and the resistance is equal to the ratio of the voltage difference to the current.

[0133] In step S220 , the resistance is compared with a preset resistance value, and when the resistance exceeds a deviation range of the preset resistance value, it is inferred that there is an offset between the first metal line to be tested and the second metal line to be tested.

[0134] The preset resistance value can be a theoretical or empirical value of the resistance when there is no offset between the first metal wire 1 to be tested and the second metal wire 2 to be tested, as estimated based on process conditions. The deviation range of the preset resistance value can be a resistance deviation range that does not affect the electrical performance of the first metal wire 1 to be tested and the second metal wire 2 to be tested. In other words, the deviation range of the preset resistance value is the allowable range within which the actual measured resistance value deviates from the theoretical or empirical resistance value.

[0135] 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.

[0136] Step S240 , determining the presence of the offset phenomenon and the offset direction based on the microscopic topography image.

[0137] 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.

[0138] The present invention discloses a method for testing alignment shift between metal layers. The method can apply voltages 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. Alternatively, the method can apply a preset current 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, and compare the breakdown voltage or resistance with a preset voltage value or a preset resistance value. When the breakdown voltage or resistance exceeds a preset deviation range of the preset voltage value or the preset resistance value, it is inferred that there is an overlay shift between the first metal line 1 to be tested and the second metal line 2 to be tested. The direction of the overlay shift 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, the present invention uses a semiconductor test structure to detect whether there is an overlay shift between upper and lower metal lines and determine the specific direction of the overlay shift, providing a reference window for metal layer overlay shift improvement and monitoring the process, thereby helping to 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 wire 1 to be tested and the second metal wire 2 to be tested, and no further sectioning is required, which increases the test efficiency.

[0139] It should be noted that although the steps of the metal layer alignment offset testing method disclosed herein 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 steps must be performed to achieve the desired results. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or a single step may be broken down into multiple steps.

[0140] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being 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, an interlayer dielectric layer is filled between the first metal layer to be tested and the second metal layer to be tested, the first metal layer to be tested includes first metal lines to be tested with equal line width, and the second metal layer to be tested includes second metal lines to be tested with equal line width; A conductive test structure includes a first conductive test portion and / or a second conductive test portion, wherein the first conductive test portion is distributed in the same layer as the first metal layer to be tested, and the second conductive test portion is distributed in the same layer as the second metal layer to be tested. When the conductive test structure includes the first conductive test portion and the second conductive test portion, the first conductive test portion and the second conductive test portion are insulated by the interlayer dielectric layer. The first conductive test portion has a uniform line width at all locations, and the second conductive test portion also has a uniform line width at all locations. The first conductive test portion is uniformly spaced from the first metal line to be tested, and the second conductive test portion is uniformly spaced from the second metal line to be tested. The first metal line to be tested and the second metal line to be tested are connected by a plurality of vias, the vias penetrating the interlayer dielectric layer; the vias are distributed in two directions on the first metal line to be tested and the second metal line to be tested, so as to monitor the alignment offset of the first metal line to be tested and the second metal line to be tested in two directions; 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, wherein: 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, wherein 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 also has a serpentine structure, and the serpentine structure corresponding to the second metal line to be tested is used as a second serpentine structure, wherein 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 portion includes a first comb structure and a second comb structure, wherein the first comb structure is placed on one side of the first serpentine structure, and each comb tooth of the first comb structure is inserted into a different first groove respectively; 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 inserted into a different second groove respectively; 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, wherein: 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 through 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, wherein: 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, wherein: 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, wherein: 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, wherein: The first metal wire to be tested includes a plurality of interconnected first comb-shaped structures, 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, the plurality of first comb teeth and the first comb spine forming 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 including a second comb spine and a plurality of second comb teeth located on one side or both sides of the second comb spine, the plurality of second comb teeth and the second comb spine forming a plurality of second tooth gaps distributed at intervals; The first conductive testing portion includes a third comb-shaped structure, and each comb tooth of the third comb-shaped structure is correspondingly 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, the first test pad is connected to the first conductive test portion; or the conductive test structure comprises the second conductive test portion, 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, wherein: 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, wherein: 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, wherein: 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, wherein: The first test pad is connected to the third comb-shaped structure or the fourth comb-shaped structure, and the second test pad is connected to the first comb-shaped structure or the second comb-shaped structure.

13. The semiconductor test structure according to claim 1, wherein: The first conductive testing portion is a serpentine structure, and the serpentine structure corresponding to the first conductive testing 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 testing portion also has a serpentine structure. The serpentine structure corresponding to the second conductive testing 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. 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 inserted into a different first recess respectively; 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, wherein: 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.

15. A method for testing alignment deviation between metal layers, characterized in that: The testing method uses the semiconductor test structure according to any one of claims 1 to 14 for testing, and the testing method includes: 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 an offset phenomenon exists 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 cross-section processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at cross-sections in different directions; The existence of the offset phenomenon is determined based on the microscopic topography, and the offset direction is determined.

16. The method for testing metal layer alignment deviation according to claim 15, wherein: 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, wherein: 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 alignment deviation between metal layers, characterized in that: The testing method uses the semiconductor test structure according to any one of claims 1 to 14 for testing; the testing method comprises: measuring the resistance between the first metal wire to be tested and the first conductive test portion; or measuring the resistance between the second metal wire to be tested and the second conductive test portion; comparing the resistance with a preset resistance value, and inferring that an offset phenomenon exists between the first metal wire to be tested and the second metal wire to be tested when the resistance exceeds a preset deviation range of the preset resistance value; Performing cross-section processing on the semiconductor test structure in different directions to obtain microscopic morphology images of the semiconductor test structure at cross-sections in different directions; The existence of the offset phenomenon is determined based on the microscopic topography, and the offset direction is determined.

19. The method for testing metal layer alignment deviation according to claim 18, wherein: Measuring the resistance between the first metal line to be tested and the first 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 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, wherein: Measuring 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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