CN120015743A

CN120015743A - Semiconductor test structure and metal layer alignment deviation test method

Info

Publication number: CN120015743A
Application number: CN202510446110.9A
Authority: CN
Inventors: 陈煜倩
Original assignee: Shenzhen Shengweixu Technology Co ltd
Current assignee: Shenzhen Shengweixu Technology Co ltd
Priority date: 2025-04-10
Filing date: 2025-04-10
Publication date: 2025-05-16
Anticipated expiration: 2045-04-10
Also published as: CN120015743B

Abstract

The present invention provides a semiconductor test structure and a test method for alignment deviation between metal layers, and relates to the semiconductor field. 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 line width of the first conductive test part is equal at all places, and the line width of the second conductive test part is also equal at all places; the spacing between the first conductive test part and the first metal line to be tested is equal at all places, and the spacing between the second conductive test part and the second metal line to be tested is equal at all places; the first metal line to be tested and the second metal line to be tested are connected through vias; the first test pad is connected to the first conductive test part or the second conductive test part; the second test pad is connected to the first metal line to be tested or the second metal line to be tested.

Description

Semiconductor test structure and method for testing inter-metal alignment offset

Technical Field

The disclosure relates to the field of semiconductor technology, and in particular relates to a semiconductor test structure and a test method for inter-metal alignment offset.

Background

The memory has the advantages of small volume, high integration degree, high transmission speed and the like, and is widely applied to mobile equipment such as mobile phones, tablet computers and the like. In the process of manufacturing the semiconductor structure, due to the influence of factors such as manufacturing process and the like, the phenomenon of offset between the upper conductive layer and the lower conductive layer of the conductive column occasionally occurs, so that the electrical performance of the device is affected. Therefore, it is necessary to detect the offset of the upper and lower conductive layers during the process to evaluate the process reliability.

However, when the conventional test structure performs the breakdown voltage test and detects whether the metal layer offset (coverage shift) exists, the offset in different directions needs to be implemented by different test structures, which results in more test structures and larger area occupied in the dicing channels by the test structures.

It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the present disclosure and thus may include information that does not constitute prior art known to those of ordinary skill in the art.

Disclosure of Invention

The present disclosure provides a semiconductor test structure and a test method for inter-metal alignment offset, which can detect offset in different directions, reduce the number of test structures in dicing lanes, and reduce the area occupied by the test structures.

According to one aspect of the present disclosure, there is provided a semiconductor test structure comprising:

The first metal layer to be tested and the second metal layer to be tested are stacked and distributed, interlayer dielectric layers are filled between the first metal layer to be tested and the second metal layer to be tested, the first metal layer to be tested comprises first metal wires to be tested with equal line widths, and the second metal layer to be tested comprises second metal wires to be tested with equal line widths;

The conductive test structure comprises a first conductive test part and/or a second conductive test part, wherein the first conductive test part and the first metal layer to be tested are distributed in the same layer, and the second conductive test part and the second metal layer to be tested are distributed in the same layer; the first conductive test part and the first metal wire to be tested are equal in distance everywhere, and the second conductive test part and the second metal wire to be tested are equal in distance everywhere;

the first metal wire to be tested and the second metal wire to be tested are connected through a plurality of through holes, and the through holes penetrate through the interlayer dielectric layer;

A first test pad connected to the first conductive test section or the second conductive test section;

The second test pad is connected with the first metal wire to be tested or the second metal wire to be tested.

In an exemplary embodiment of the disclosure, the first metal wire to be tested is in a serpentine structure, the serpentine structure corresponding to the first metal wire to be tested is used as a first serpentine structure, one side of the first serpentine structure is provided with a plurality of first grooves distributed at intervals, the other side of the first serpentine structure is provided with a plurality of second grooves distributed at intervals, and a plurality of first grooves and a plurality of second grooves are distributed alternately;

The second metal wire to be detected is also in a serpentine structure, the serpentine structure corresponding to the second metal wire to be detected is used as a second serpentine structure, one side of the second serpentine structure is provided with a plurality of third grooves which are distributed at intervals, the other side of the second serpentine structure is provided with a plurality of fourth grooves which are distributed at intervals, and a plurality of third grooves and a plurality of fourth grooves are alternately distributed;

The first conductive test part comprises a first comb structure and a second comb structure, wherein the first comb structure is arranged 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-shaped structure is arranged on the other side of the first serpentine-shaped structure, and each comb tooth of the second comb-shaped structure is correspondingly inserted into a different second groove respectively;

The second conductive test part comprises a third comb structure and a fourth comb structure, wherein the third comb structure is arranged on one side of the second serpentine structure, each comb tooth of the third comb structure is correspondingly inserted into a different third groove, the fourth comb structure is arranged on the other side of the second serpentine structure, and each comb tooth of the fourth comb structure is correspondingly inserted into a different fourth groove.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test part, the first test pad is connected with the first conductive test part, or the conductive test structure includes the second conductive test part, the first test pad is connected with the second conductive test part;

And the first serpentine structure and the second serpentine structure are connected through a plurality of through holes, and the second test pad is connected with the first serpentine structure or the second serpentine structure.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test part, and the first test pad is connected with the first comb structure or the second comb structure.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the second conductive test part, and the first test pad is connected with the third comb structure or the fourth comb structure.

In one 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.

In an exemplary embodiment of the disclosure, the first metal wire to be tested includes a plurality of first comb structures that are mutually communicated, the first comb structures include a first comb ridge and a plurality of first comb teeth that are located at one side or two sides of the first comb ridge, and a plurality of first tooth slits that are distributed at intervals are enclosed by the plurality of first comb teeth and the first comb ridge;

The second metal wire to be tested comprises a plurality of second comb-shaped structures which are communicated with one another, wherein each second comb-shaped structure comprises a second comb ridge and a plurality of second comb teeth which are positioned on one side or two sides of the second comb ridge, and a plurality of second tooth gaps which are distributed at intervals are formed by the second comb teeth and the second comb ridge in a surrounding mode;

The first conductive test part comprises a third comb-shaped structure, and each comb tooth of the third comb-shaped structure is correspondingly inserted into a different first tooth slit;

the second conductive test part comprises a fourth comb-shaped structure, and each comb tooth of the fourth comb-shaped structure is correspondingly inserted into a different second tooth slit.

In an exemplary embodiment of the present disclosure, the first comb structure and the second comb structure are connected by a plurality of vias, and the second test pad is connected to the first comb structure or the second comb structure.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test part, and the first test pad is connected with the third comb structure.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the second conductive test part, and the first test pad is connected with the fourth comb structure.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test part and the second conductive test part, and the first comb structure and the second comb structure are connected by a plurality of vias.

In one exemplary embodiment of the present disclosure, the first test pad is connected with the third comb structure or the fourth comb structure, and the second test pad is connected with the first comb structure or the second comb structure.

In an exemplary embodiment of the present disclosure, the first conductive test part is a serpentine structure, and a serpentine structure corresponding to the first conductive test part is used as a third serpentine structure, wherein one side of the third serpentine structure is provided with a plurality of first concave parts distributed at intervals, the other side of the third serpentine structure is provided with a plurality of second concave parts distributed at intervals, and a plurality of first concave parts and a plurality of second concave parts are alternately distributed;

The second conductive test part is also in a serpentine structure, the serpentine structure corresponding to the second conductive test part is used as a fourth serpentine structure, one side of the fourth serpentine structure is provided with a plurality of third concave parts which are distributed at intervals, the other side of the fourth serpentine structure is provided with a plurality of fourth concave parts which are distributed at intervals, and the plurality of third concave parts and the plurality of fourth concave parts are alternately distributed;

The first metal wire to be tested comprises a fifth comb-shaped structure and a sixth comb-shaped structure, wherein the fifth comb-shaped structure is arranged on one side of the third serpentine-shaped structure, and each comb tooth of the fifth comb-shaped structure is correspondingly inserted into a different first concave part respectively;

the second metal wire to be tested comprises a seventh comb-shaped structure and an eighth comb-shaped structure, wherein the seventh comb-shaped structure is arranged on one side of the fourth serpentine-shaped structure, each comb tooth of the seventh comb-shaped structure is correspondingly inserted into a different third concave part, the eighth comb-shaped structure is arranged on the other side of the fourth serpentine-shaped structure, and each comb tooth of the eighth comb-shaped structure is correspondingly inserted into a different fourth concave part.

In one exemplary embodiment of the present disclosure, the conductive test structure includes the first conductive test part, the first test pad is connected with the first conductive test part, or the conductive test structure includes the second conductive test part, the first test pad is connected with the second conductive test part, or the conductive test structure includes the first conductive test part and the second conductive test part, the first test pad is connected with the first conductive test part or the second conductive test part;

The fifth comb structure is connected with the seventh comb structure through a plurality of through holes, the sixth comb structure is connected with the eighth comb structure through a plurality of through holes, and the second test pad is connected with any one of the fifth comb structure, the sixth comb structure, the seventh comb structure or the eighth comb structure.

According to an aspect of the present disclosure, there is provided a test method of inter-metal alignment shift, the test method using the semiconductor test structure described in any one of the above, the test method comprising:

detecting a breakdown voltage between the first metal line to be tested and the first conductive test part, or detecting a breakdown voltage between the second metal line to be tested and the second conductive test part;

Comparing the breakdown voltage with a preset voltage value, and presuming that an offset phenomenon exists between the first metal wire to be detected and the second metal wire to be detected when the breakdown voltage exceeds a preset deviation range of the preset voltage value;

Performing slicing treatment on the semiconductor test structure in different directions to obtain microscopic morphology graphs of the semiconductor test structure at sections in different directions;

Determining that the offset phenomenon exists according to the micro-topography map, and determining an offset direction.

In one exemplary embodiment of the present disclosure, detecting a breakdown voltage between the first metal line to be tested and the first conductive test part includes applying a first voltage and a second voltage to the first test pad and the second test pad, respectively, and when the first metal line to be tested and the first conductive test part are broken down, a voltage difference between the first voltage and the second voltage is the breakdown voltage.

In one exemplary embodiment of the present disclosure, detecting a breakdown voltage between the second metal line under test and the second conductive test portion 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 under test and the second conductive test portion are broken down, a voltage difference between the first voltage and the second voltage is the breakdown voltage.

According to one aspect of the present disclosure, there is provided a method for testing inter-metal alignment shift, the method for testing using the semiconductor test structure according to any one of the above, the method for testing comprising:

measuring the resistance between the first metal wire to be tested and the first conductive test part, or measuring the resistance between the second metal wire to be tested and the second conductive test part;

Comparing the resistor with a preset resistance value, and presuming that an offset phenomenon exists between the first metal wire to be tested and the second metal wire to be tested when the resistor exceeds a preset deviation range of the preset resistance value;

In one exemplary embodiment of the present disclosure, measuring the resistance between the first wire to be tested and the first conductive test part includes applying a preset current between the first test pad and the second test pad, measuring a differential pressure between the first wire to be tested and the first conductive test part, the resistance being equal to a ratio of the differential pressure to the preset current.

In one exemplary embodiment of the present disclosure, measuring the resistance between the second metal wire under test and the second conductive test part includes applying a preset current to flow between the first test pad and the second test pad, measuring a differential pressure between the second metal wire under test and the second conductive test part, the resistance being equal to a ratio of the differential pressure to the preset current.

The semiconductor test structure and the test method for the inter-metal alignment offset can apply voltage to the first test pad and the second test pad respectively, detect breakdown voltage between the conductive test structure and the first metal wire to be tested or the second metal wire to be tested, or apply preset current to flow between the first test pad and the second test pad, measure resistance between the conductive test structure and the first metal wire to be tested or the second metal wire to be tested, compare the breakdown voltage or the resistance with a preset voltage value or a preset resistance value, and infer that offset phenomenon exists between the first metal wire to be tested and the second metal wire to be tested when the breakdown voltage or the resistance exceeds a preset offset range of the preset voltage value or the preset resistance value, and further determine the offset direction between the second metal wire to be tested and the first metal wire to be tested in a slicing mode. In other words, through a semiconductor test structure in the disclosure, whether an offset (overlay shift) phenomenon exists between the upper and lower metal lines can be detected, a specific direction of the offset can be determined, a window reference of the metal layer offset (overlay shift) is provided for improving the semiconductor process, and the process is monitored, so that the improvement of the process reliability is facilitated. Because the area is limited to test structure (Testkey) is put, the quantity of semiconductor test structure that can put in this disclosure reduces, compares in current scheme through putting two different test structures in order to detect two different direction offsets (overlapping shift) respectively, and this disclosure proposes to detect two directions simultaneously with a test structure, can save the area of putting of semiconductor test structure, reduces manufacturing cost, still can practice thrift test time and test number of times simultaneously, improves efficiency of software testing. In addition, when the breakdown voltage or the resistance does not exceed the preset voltage value or the preset deviation range of the preset resistance value, the fact that the first metal wire to be tested and the second metal wire to be tested do not deviate can be directly judged, slicing is not needed, and testing efficiency is high.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure. It will be apparent to those of ordinary skill in the art that the drawings in the following description are merely examples of the disclosure and that other drawings may be derived from them without undue effort.

Fig. 1 is a schematic diagram of a semiconductor test structure according to an embodiment of the disclosure.

Fig. 2 is a schematic diagram of a first metal line to be tested and a first conductive test portion according to an embodiment of the disclosure.

Fig. 3 is a schematic diagram of a semiconductor test structure when the conductive test structure includes only the first conductive test portion according to an embodiment of the disclosure.

Fig. 4 is a schematic diagram of a semiconductor test structure when the conductive test structure includes only the second conductive test portion according to an embodiment of the disclosure.

Fig. 5 is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the disclosure includes only a first conductive test portion, and the line width of the first metal line to be tested is greater than that of the second metal line to be tested.

Fig. 6 is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the disclosure includes only a first conductive test portion, and the line width of the first metal line to be tested is smaller than that of the second metal line to be tested.

Fig. 7 is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the disclosure includes only the second conductive test portion, and the line width of the first metal line to be tested is greater than that of the second metal line to be tested.

Fig. 8 is a schematic diagram of a semiconductor test structure in which the conductive test structure in the embodiment of the disclosure includes only the second conductive test portion, and the line width of the first metal line to be tested is smaller than that of the second metal line to be tested.

Fig. 9 is a schematic diagram of a semiconductor test structure according to an embodiment of the disclosure.

Fig. 10 is a schematic diagram of a semiconductor test structure according to an embodiment of the disclosure.

Fig. 11 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 according to an embodiment of the disclosure.

Fig. 12 is a schematic diagram of a semiconductor test structure according to an embodiment of the disclosure.

Fig. 13 is a schematic diagram of a method for testing inter-metal alignment shift in an embodiment of the disclosure.

Fig. 14 is a schematic diagram of a method for testing inter-metal alignment shift in another embodiment of the present disclosure.

Reference numerals illustrate:

1. A first metal line to be tested; 101, a first groove; 102, second grooves, 11, first comb structures, 111, first comb ridges, 112, first comb teeth, 113, first comb slits, 12, first connecting lines, 13, fifth comb structures, 131, fifth comb structures, 14, sixth comb structures, 141, sixth comb structures, 15, seventh comb structures, 151, seventh comb structures, 16, eighth comb structures, 161, eighth comb structures, 2, second metal wires to be tested, 201, third grooves, 202, fourth grooves, 3, conductivity test structures, 31, first conductivity test parts, 301, first concave parts, 302, second concave parts, 311, first comb structures, 3111, first comb structures, 312, second comb structures, 3121, second comb structures, 313, third comb structures, 3131, third comb ridges, 32, third comb structures, 314, third connecting lines, 32, second conductivity test parts, 303, 321, third comb structures, 321, fourth concave parts, 31, 312, second comb structures, 3121, second comb structures, 313, third comb structures, 31, third comb structures, 314, third comb structures, 32, second conductive test parts, 303, 321, third comb structures, fourth concave parts, 3216, fourth comb structures, and fourth test pads.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted. Furthermore, the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale.

Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another component, these terms are used in this specification for convenience only, such as in terms of the orientation of the examples described in the figures. It will be appreciated that if the device of the icon is flipped upside down, the recited "up" component will become the "down" component. When a structure is "on" another structure, it may mean that the structure is integrally formed with 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.

The terms "a," "an," "the," and "at least one" are used to indicate the presence of one or more elements/components/etc., the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc., in addition to the listed elements/components/etc., and the terms "first," "second," etc., are used as labels only, and not as limitations on the number of objects it is intended to use.

In the semiconductor manufacturing industry, reliability testing is a key element for ensuring the process stability and reliability of products. This process typically 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 important indicators for measuring dielectric layer insulation performance, and is important for evaluating the voltage-withstanding capability of a semiconductor device.

In the conventional design of a breakdown voltage test structure, metal layer groups on the upper side and the lower side of a dielectric layer are usually designed independently, and in order to meet the test requirement, the metal layer groups (i.e. the test structure) occupy a certain placement area. However, with the continuous progress of semiconductor manufacturing technology, the structure on the wafer is more and more complex, and the test structure is mostly placed in the scribe line between two adjacent chips on the wafer and is used as the monitoring structure of the process, and the placement area and the number of the test structures of the same test type are greatly limited by the placement position of the test structure. Meanwhile, alignment problems in the process, such as alignment deviation between upper and lower metal layers and middle through holes or between different photoetching layers, namely overlay layer deviation, have significant influence on test results. Such a shift may not only lead to inaccurate test results of breakdown voltage or resistance, but may also affect the performance and reliability of the entire semiconductor device.

Currently, test structures with metal layers aligned in the same direction exhibit singleness in detecting the direction of the offset of the cover layer, i.e., only the offset in a specific direction can be detected. To fully evaluate the offset condition, it is often necessary to design a plurality of test structures in different directions, which undoubtedly increases the complexity of the test and the occupation of the wafer area, and also affects the test efficiency.

Based on this, the embodiment of the disclosure provides a semiconductor test structure, as shown in fig. 1, 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 distributed in a laminated mode, 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 comprises a first metal wire to be tested 1 with the same line width, and the second metal layer to be tested comprises a second metal wire to be tested 2 with the same line width;

The conductive test structure 3 comprises a first conductive test part 31 and/or a second conductive test part 32, wherein the first conductive test part 31 and a first metal layer to be tested are distributed in the same layer, and the second conductive test part 32 and a second metal layer to be tested are distributed in the same layer, wherein the line width is equal at each part of the first conductive test part 31, the line width is equal at each part of the second conductive test part 32, the distance between the first conductive test part 31 and the first metal wire to be tested 1 is equal at each part, and the distance between the second conductive test part 32 and the second metal wire to be tested 2 is equal at each part;

The first metal wire 1 to be tested is connected with the second metal wire 2 to be tested through a plurality of through holes 4, and the through holes 4 penetrate through an interlayer dielectric layer (not shown in the figure);

the first test pad 5 is connected to the first conductive test part 31 or the second conductive test part 32;

The second test pad 6 is connected to the first metal line to be tested 1 or the second metal line to be tested 2.

The semiconductor test structure disclosed by the invention can apply voltages to the first test pad 5 and the second test pad 6 respectively, detect the breakdown voltage between the conductive test structure 3 and the first metal wire to be tested 1 or the second metal wire to be tested 2, or apply 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 wire to be tested 1 or the second metal wire to be tested 2, compare the breakdown voltage or the resistance with a preset voltage value or a preset resistance value, and infer that the offset phenomenon exists between the first metal wire to be tested 1 and the second metal wire to be tested 2 when the breakdown voltage or the resistance exceeds a preset deviation range of the preset voltage value or the preset resistance value, and further determine the offset direction between the second metal wire to be tested 2 and the first metal wire to be tested 1 in a slice cutting mode. In the method, whether the offset phenomenon exists between the upper metal line and the lower metal line can be detected through the semiconductor test structure, the specific direction of the offset is determined, data support is provided for improvement of a semiconductor process, and the method is beneficial to improvement of process reliability. Because the area is limited to test structure (Testkey) is put, the quantity of semiconductor test structure that can put in this disclosure reduces, compares in current scheme through putting two different test structures in order to detect two different direction offsets (overlapping shift) respectively, and this disclosure proposes to detect two directions simultaneously with a test structure, can save the area of putting of semiconductor test structure, reduces manufacturing cost, still can practice thrift test time and test number of times simultaneously, improves efficiency of software testing. In addition, when the breakdown voltage or the resistance does not exceed the preset voltage value or the preset deviation range of the preset resistance value, the fact that the first metal wire 1 to be tested and the second metal wire 2 to be tested do not have deviation phenomenon can be directly judged, slicing is not needed, and testing efficiency is high.

The following is a detailed description of various portions of the semiconductor test structures of the present disclosure and their specific details:

The first metal layer to be tested and the second metal layer to be tested may be stacked and distributed, and in some embodiments of the present disclosure, an interlayer dielectric layer is filled between the first metal layer to be tested and the second metal layer to be tested. With continued reference to fig. 1, the first metal layer to be tested may include first metal lines 1 to be tested having an equal line width, and the second metal layer to be tested may include second metal lines 2 to be tested having an equal line width. That is, the line widths of the first metal lines to be measured 1 in the first metal layer to be measured are equal everywhere, and at the same time, the line widths of the second metal lines to be measured 2 in the second metal layer to be measured are equal everywhere. The line widths of the first metal line to be tested 1 and the second metal line to be tested 2 may be equal or unequal, and are not particularly limited herein.

In an exemplary embodiment of the present disclosure, the line width of the first metal line to be measured 1 and the line width of the second metal line to be measured 2 both follow the minimum line width rule (MIN DESIGN rule), that is, the line widths of the first metal line to be measured 1 and the second metal line to be measured 2 are the minimum line widths on the basis of satisfying the conductive characteristics thereof.

The material of the first metal line 1 to be tested may be a material with relatively high conductivity, for example, copper, aluminum, tungsten or titanium nitride, but may be other materials with relatively high conductivity, which are not listed here. The material of the interlayer dielectric layer may be an insulating material, for example, silicon oxide or silicon nitride. The material of the second metal wire 2 to be tested may be a material with relatively high conductivity, for example, copper, aluminum, tungsten or titanium nitride, but may be other materials with relatively high conductivity, which are not listed here.

In some embodiments of the present disclosure, as shown in fig. 2, when the first metal wire 1 to be tested is a serpentine structure, an S-shaped structure or a linear structure, in order to facilitate distinguishing 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 may be used as a first serpentine structure, one side of the first serpentine structure has a plurality of first grooves 101 distributed at intervals, the other side has a plurality of second grooves 102 distributed at intervals, and 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 itself of the first serpentine structure.

With continued reference to fig. 1, the structure of the second metal wire 2 to be tested may be a serpentine structure, an S-shaped structure or a linear structure, and in this disclosure, the second metal wire 2 to be tested is taken as an example of the serpentine structure, and details of the arrangement and the matching relationship with other structures are described. For convenience of distinction, the serpentine structure corresponding to the second metal wire 2 to be tested may 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, where 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 itself of the second serpentine structure.

In an exemplary embodiment of the disclosure, as shown in fig. 1 and 2, the first metal wire to be tested 1 and the second metal wire to be tested 2 may be connected through a plurality of vias 4, the vias 4 may penetrate through the interlayer dielectric layer, and the vias 4 are filled with a conductive material, that is, the first metal wire to be tested 1 and the second metal wire to be tested 2 may be communicated through the conductive material. The line width of the via 4 also follows the minimum line width rule (MIN DESIGN rule), i.e., the line width of the via 4 is the minimum line width based on satisfying its own conductive characteristics.

In some embodiments of the present disclosure, as shown in fig. 2 and 3, the conductive test structure 3 may include a first conductive test portion 31, where the first conductive test portion 31 is distributed in the same layer as the first metal layer to be tested. The line widths of the first conductive test parts 31 are equal everywhere, that is, the line widths of the regions in the first conductive test parts 31 are equal everywhere, and the pitches of the first conductive test parts 31 and the first metal line 1 to be tested are equal everywhere (that is, a=b=c=d in fig. 2). It should be noted that, the line width of the first conductive testing portion 31 follows the minimum line width rule (MIN DESIGN rule), that is, the line width of the first conductive testing portion 31 is the minimum line width based on satisfying the conductive characteristic of itself. The distance between the first conductive test part 31 and the first metal line 1 to be tested is the minimum distance capable of ensuring that the first conductive test part and the first metal line are not conducted or coupled with each other.

The shape of the first conductive test part 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 wire 1 to be tested is linear, the first conductive testing portion 31 is linear, and when the first metal wire 1 to be tested is serpentine or S-shaped, the first conductive testing portion 31 has a comb-like structure (as shown in fig. 1-3).

In other embodiments of the present disclosure, as shown in fig. 4, the conductive test structure 3 may include a second conductive test portion 32, where the second conductive test portion 32 is distributed in the same layer as the second metal layer to be tested. The line widths are also equal throughout the second conductive test portion 32, i.e., the line widths of the regions in the second conductive test portion 32 are equal throughout. The distance between the second conductive test portion 32 and the second metal line 2 to be tested is equal everywhere, and it should be noted that the line width of the second conductive test portion 32 follows the minimum line width rule (MIN DESIGN rule), that is, the line width of the second conductive test portion 32 is the minimum line width based on the conductive characteristic of the second conductive test portion. The distance between the second conductive test part 32 and the second metal line to be tested 2 is the minimum distance capable of ensuring that the two are not conducted or coupled with each other.

The shape of the second conductive test part 32 matches the shape of the second metal line to be tested 2 in the second metal layer to be tested. For example, when the second metal wire 2 to be tested is linear, the second conductive testing portion 32 is also linear, and when the second metal wire 2 to be tested is serpentine or S-shaped, the second conductive testing portion 32 has a comb-like structure (as shown in fig. 1 and 4).

In still other embodiments of the present disclosure, please continue to refer to fig. 1, 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 line width of each part of the first conductive test part 31 is equal to that of each part of the second conductive test part 32, the distance between the first conductive test part 31 and the first metal wire 1 to be tested is equal to that between the second conductive test part 32 and the second metal wire 2 to be tested is equal to that between the first conductive test part 31 and the first metal wire 1 to be tested.

In an exemplary embodiment of the present disclosure, as shown in fig. 1-3, when the first metal wire 1 to be tested is in a serpentine structure, the first conductive testing portion 31 may include a first comb structure 311 and a second comb structure 312, wherein the first comb structure 311 is disposed at one side of the first serpentine structure, the number of teeth 3111 of the first comb structure is matched with the number of the first grooves 101, and the teeth 3111 of the first comb structure are respectively inserted into different first grooves 101, and all areas of the teeth 3111 of the first comb structure are equal to the spacing between the surrounding first metal wire 1 to be tested. The second comb structure 312 is disposed on the other side of the first serpentine structure, the number of the teeth 3121 of the second comb structure is matched with the number of the second grooves 102, and the teeth 3121 of the second comb structure are respectively inserted into different second grooves 102 correspondingly, and the intervals between all areas of the teeth 3121 of the second comb structure and the first metal wires 1 to be tested around the same are equal.

Referring to fig. 1 and fig. 4, when the second metal wire 2 to be tested is in a serpentine structure, the second conductive testing portion 32 may include a third comb structure 321 and a fourth comb structure 322, wherein the third comb structure 321 is disposed at one side of the second serpentine structure, the number of teeth 3211 of the third comb structure is matched with the number of grooves 201, and the teeth 3211 of the third comb structure are respectively inserted into different grooves 201, and the spacing between all areas of the teeth 3211 of the third comb structure and the surrounding second metal wire 2 to be tested is equal. The fourth comb structure 322 is disposed on the other side of the second serpentine structure, the number of the teeth 3221 of the fourth comb structure is matched with the number of the fourth grooves 202, and the teeth 3221 of the fourth comb structure are respectively inserted into different fourth grooves 202 correspondingly, and the intervals between all areas of the teeth 3221 of the fourth comb structure and the second metal wires 2 to be tested around the same are equal.

With continued reference to fig. 1, 3 and 4, the first test pad 5 may be in the form of a sheet, which may be made of a conductive material, such as copper. The first test pad 5 may be connected with the first conductive test part 31 or the second conductive test part 32. With continued reference to fig. 3, when the conductive test structure 3 includes only the first conductive test portion 31, the first serpentine structure and the second serpentine structure are connected through the plurality of vias 4, and the first test pad 5 is connected to the first conductive test portion 31, for example, the first test pad 5 may be connected to the first comb structure 311 in the first conductive test portion 31 or connected to the second comb structure 312 in the first conductive test portion 31, where a connection area between the first test pad 5 and the first conductive test portion 31 is not specifically limited.

With continued reference to fig. 4, when the conductive test structure 3 includes only the second conductive test portion 32, the first serpentine structure and the second serpentine structure are connected through the plurality of vias 4, and the first test pad 5 is connected to the second conductive test portion 32, for example, the first test pad 5 may be connected to the third comb structure 321 in the second conductive test portion 32 or connected to the fourth comb structure 322 in the second conductive test portion 32, where a connection area between the first test pad 5 and the second conductive test portion 32 is not specifically limited.

When the conductive test structure 3 includes both the first conductive test part 31 and the second conductive test part 32, the first serpentine structure and the second serpentine structure may be connected by a plurality of vias 4. The first test pad 5 may be connected with the first conductive test part 31 or the second conductive test part 32. For example, the first test pad 5 may 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.

With continued reference to fig. 1, 3 and 4, the second test pad 6 may also be in the form of a sheet, which may be made of a conductive material, such as copper. The second test pad 6 may be connected to an end of the first metal wire 1 to be tested or an end of the second metal wire 2 to be tested. For example, the second test pad 6 may be connected with the first serpentine or the second serpentine. The 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 wire to be tested 1 or the second metal wire to be tested 2, or the preset current can be applied 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 wire to be tested 1 or the second metal wire to be tested 2, the breakdown voltage or the resistance is compared with the preset voltage value or the preset resistance value, when the breakdown voltage or the resistance exceeds the preset deviation range of the preset voltage value or the preset resistance value, the offset phenomenon exists between the first metal wire to be tested 1 and the second metal wire to be tested 2 is presumed, and the offset direction between the second metal wire to be tested 2 and the first metal wire to be tested 1 can be further determined by the slicing mode.

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 finally detected breakdown voltage or resistance is the breakdown voltage or resistance corresponding to the first metal wire 1 to be tested, and when the first test pad 5 is connected to the third comb structure 321 or the fourth comb structure 322, the finally detected breakdown voltage or resistance is the breakdown voltage or resistance corresponding to the second metal wire 2 to be tested.

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

In some embodiments of the present disclosure, as shown in fig. 5, the conductive test structure 3 includes only the first conductive test portion 31, and 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, and 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. In some embodiments of the present disclosure, as shown in fig. 6, the conductive test structure 3 includes only the first conductive test portion 31, and 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, and 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. In some embodiments of the present disclosure, as shown in fig. 7, the conductive test structure 3 includes only the second conductive test portion 32, and 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, and 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. In some embodiments of the present disclosure, as shown in fig. 8, the conductive test structure 3 includes only the second conductive test portion 32, and 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, and 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.

In an exemplary embodiment of the present disclosure, when the line widths of the first to-be-tested metal line 1 and the second to-be-tested metal line 2 are not equal, and the conductive test structure 3 includes not only the first conductive test part 31 but also the second conductive test part 32, the line width of the to-be-tested metal line with the larger line width is equal to the line width of the conductive test part corresponding thereto, and the line width of the to-be-tested metal line with the smaller line width is not equal to the line width of the conductive test part corresponding thereto. As shown in fig. 9, when the width of the first metal wire 1 to be tested is greater than the width of the second metal wire 2 to be tested, the width of the first conductive test part 31 is equal to the width of the first metal wire 1 to be tested, and the width of the second conductive test part 32 is greater than the width of the second metal wire 2 to be tested, and at the same time, the width of the second conductive test part 32 is greater than the width of the first conductive test part 31. The line width of the second conductive test part 32 is the twice of 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. e in fig. 9), the distance between the center line of the second conductive test part 32 and the center line of the second metal wire 2 to be tested (i.e. f in fig. 9), and the line width of the second metal wire 2 to be tested. As shown in fig. 10, 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 part 32 is equal to the line width of the second metal line to be tested 2, and the line width of the first conductive test part 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 part 31 is larger than the line width of the second conductive test part 32. The line width of the first conductive test part 31 is the twice of the distance between the center line of the second conductive test part 32 and the center line of the second metal line to be tested 2 (i.e. g in fig. 10), the distance between the center line of the first conductive test part 31 and the center line of the first metal line to be tested 1 (i.e. h in fig. 10), and the line width of the first metal line to be tested 1.

In one exemplary embodiment of the present disclosure, as shown in fig. 11, the shape of the first metal line under test 1 and/or the second metal line under test 2 may 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) may have a serpentine shape, and accordingly, the first metal wire 1 to be tested and the second metal wire 2 to be tested may have a comb-like shape.

In an exemplary embodiment of the present disclosure, the first conductive test part 31 may have a serpentine structure, and the serpentine structure corresponding to the first conductive test part 31 may be regarded as a third serpentine structure, one side of the third serpentine structure has a plurality of first recesses 301 spaced apart, the other side has a plurality of second recesses 302 spaced apart, and the first recesses 301 and the plurality of second recesses 302 are alternately arranged. It should be noted that, the first recess 301 and the second recess 302 are groove-like structures defined by the structure itself of the third serpentine structure.

In some embodiments of the present disclosure, please continue to refer to fig. 11, when the first conductive testing portion 31 has a serpentine structure, the first metal line to be tested 1 in the first metal layer to be tested includes 2 metal lines, and the 2 metal lines have a comb structure. For convenience of distinction, the first metal wire 1 to be tested may be defined to include a fifth comb structure 13 and a sixth comb structure 14, wherein the fifth comb structure 13 is disposed at one side of the third serpentine structure, the number of teeth 131 of the fifth comb structure is matched with the number of the first concave portions 301, the teeth 131 of the fifth comb structure are respectively inserted into different first concave portions 301 correspondingly, the intervals between all areas of the teeth 131 of the fifth comb structure and the surrounding first conductive test portions 31 are equal, the sixth comb structure 14 is disposed at the other side of the third serpentine structure, the number of teeth 141 of the sixth comb structure is matched with the number of the second concave portions 302 correspondingly, and the intervals between all areas of the teeth 141 of the sixth comb structure and the surrounding first conductive test portions 31 are equal.

In some embodiments of the present disclosure, as shown in fig. 11, the second conductive testing part 32 may also have a serpentine structure, and the serpentine structure corresponding to the second conductive testing part 32 may be a fourth serpentine structure, where 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 recess 303 and the fourth recess 304 are groove-like structures defined by the structure itself of the fourth serpentine structure.

In some embodiments of the present disclosure, when the second conductive test portion 32 has a serpentine structure, the second metal lines to be tested 2 in the first metal layer to be tested include 2 metal lines, and the 2 metal lines have a comb structure. For convenience of distinction, the second metal wire 2 to be tested may be defined to include a seventh comb structure 15 and an eighth comb structure 16, wherein the seventh comb structure 15 is disposed at one side of the third serpentine structure, the number of teeth 151 of the seventh comb structure is matched with the number of the third concave portions 303, the teeth 151 of the seventh comb structure are respectively inserted into different third concave portions 303 correspondingly, the intervals between all areas of the teeth 151 of the seventh comb structure and the second conductive test portions 32 around the teeth are equal, the eighth comb structure 16 is disposed at the other side of the third serpentine structure, the number of teeth 161 of the eighth comb structure is matched with the number of the fourth concave portions 304, and the intervals between all areas of the teeth 161 of the eighth comb structure and the second conductive test portions 32 around the teeth of the eighth comb structure are equal correspondingly inserted into different fourth concave portions 304 respectively.

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 with the first conductive test part 31. At this time, the fifth comb structure 13 and the seventh comb structure 15 are connected through the plurality of vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected through the plurality of 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.

In some embodiments of the present disclosure, when the conductive test structure 3 includes only the second conductive test part 32, the first test pad 5 is connected with the second conductive test part 32. At this time, the fifth comb structure 13 and the seventh comb structure 15 are connected through the plurality of vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected through the plurality of 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.

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 with the first conductive test part 31 or the second conductive test part 32. At this time, the fifth comb structure 13 and the seventh comb structure 15 are connected through the plurality of vias 4, the sixth comb structure 14 and the eighth comb structure 16 are connected through the plurality of 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.

In an exemplary embodiment of the present disclosure, as shown in fig. 12, the first metal wire 1 to be tested may include a plurality of first comb structures 11 that are mutually communicated, the first comb structures 11 include first comb ridges 111 and a plurality of first comb teeth 112 located at one side or both sides of the first comb ridges 111, each of the first comb teeth 112 may be distributed in parallel, and the plurality of first comb teeth 112 and the first comb ridges 111 enclose a plurality of first tooth slits 113 that are distributed at intervals along the length direction of the first comb ridges 111. The ends of the plurality of first comb ridges 111 on the same side among the plurality of first comb structures 11 may be connected together by the first connecting line 12.

The second metal wire 2 to be tested may include a plurality of second comb structures (not shown in the drawings) which are mutually communicated, the second comb structures include second comb ridges and a plurality of second comb teeth located on one side or two sides of the second comb ridges, each second comb tooth may be distributed in parallel, and a plurality of second tooth slits distributed along the length direction of the second comb ridge at intervals are defined by the plurality of second comb teeth and the second comb ridges. The ends of the plurality of second comb ridges on the same side in the plurality of second comb structures may be connected together by a second connection line.

With continued reference to fig. 12, the first conductive testing portion 31 may include a plurality of third comb structures 313 connected to each other, the third comb structures 313 include third comb ridges 3131 and a plurality of third comb teeth 3132 located at one side or both sides of the third comb ridges 3131, and the plurality of third comb teeth 3132 may be spaced apart along a length direction of the third comb ridges 3131. Each third comb tooth 3132 of the third comb structure 313 may be respectively inserted into a different first tooth slit 113. The ends of the plurality of third comb ridges 3131 on the same side of the plurality of third comb structures 313 may be connected together by a third connection line 314, and the third connection line 314 is located on a different side from the first connection line 12.

The second conductive testing part 32 may include a plurality of interconnected fourth comb-type structures including a fourth comb ridge and a plurality of fourth comb teeth located at one side or both sides of the fourth comb ridge, and the plurality of fourth comb teeth may be spaced apart along a length direction of the fourth comb ridge. Each of the fourth comb teeth in the fourth comb-shaped structure can be respectively inserted into the different second tooth slits correspondingly. The ends of the plurality of fourth comb ridges on the same side in the plurality of fourth comb structures can be connected together through fourth connecting wires, and the fourth connecting wires and the second connecting wires are located on different sides.

In one exemplary embodiment of the present disclosure, the first comb structure 11 and the second comb structure may be connected by a plurality of vias 4. 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, for example, the first test pad 5 is connected to the third comb-shaped structures 313 in the first conductive test part 31, and for example, the first test pad 5 is connected to the third connection lines 314 connecting the third comb-shaped structures 313 in the first conductive test part 31.

When the conductive test structure 3 includes only 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 structure in the second conductive test part 32. For example, the first test pad 5 is connected to a fourth connection line connecting the fourth comb structures in the second conductive test section 32.

In one 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-shaped structure 11 and the second comb-shaped structure are connected through a plurality of through holes 4. At this time, the first test pad 5 may be connected with the third comb-type structure 313, or the first test pad 5 may be connected with the fourth comb-type structure.

The second test pad 6 may be connected to the first comb-shaped structure 11 or the second comb-shaped structure, for example, the second test pad 6 may be connected to the first connection line 12 connecting each of the first comb ridges 111 in each of the first comb-shaped structures 11, or the second test pad 6 may be connected to the second connection line connecting each of the second comb ridges in each of the second comb-shaped structures.

The disclosure further provides a testing method for inter-metal alignment offset, which uses the semiconductor testing structure in any of the above embodiments for testing, as shown in fig. 13, and the testing method may include steps S110-S140, where:

Step S110, detecting the breakdown voltage between the first metal wire to be tested and the first conductive test part, or detecting the breakdown voltage between the second metal wire to be tested and the second conductive test part.

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. The voltage value corresponding to the second voltage may be gradually increased to the second test pad 6 until breakdown occurs between the first metal line to be tested 1 and the first conductive test part 31, and when breakdown occurs between the first metal line to be tested 1 and the first conductive test part 31, a voltage difference between the first voltage and the second voltage may be regarded as a breakdown voltage.

In some embodiments of the present disclosure, the detection process of detecting the breakdown voltage between the second metal line under test 2 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. The voltage value corresponding to the second voltage may be gradually increased to the second test pad 6 until breakdown occurs between the second metal wire 2 to be tested and the second conductive test part 32, and when breakdown occurs between the second metal wire 2 to be tested and the second conductive test part 32, a voltage difference between the first voltage and the second voltage may be used as the breakdown voltage.

Step S120, comparing the breakdown voltage with a preset voltage value, and presuming that an offset phenomenon exists between the first metal wire to be tested and the second metal wire to be tested when the breakdown voltage exceeds a preset deviation range of the preset voltage value.

The preset voltage value may be a theoretical value or an empirical value of the breakdown voltage when no offset phenomenon exists between the first metal wire 1 to be tested and the second metal wire 2 to be tested, which is estimated according to the 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 wire to be tested 1 and the second metal wire to be tested 2, that is, the preset deviation range of the preset voltage value is an allowable range in which the actual measured value of the breakdown voltage deviates from the theoretical value or the empirical value of the breakdown voltage.

And step S130, slicing the semiconductor test structure in different directions to obtain microscopic morphology graphs of slicing positions in different directions in the semiconductor test structure.

The micro-topography may be a scanning electron microscope image of the semiconductor test structure.

Step S140, determining that the offset phenomenon exists according to the micro-topography map, and determining the offset direction.

And if the first metal layer to be tested and the second metal layer to be tested are found to have the offset through microscopic morphology analysis, the process for forming the first metal layer to be tested and the second metal layer to be tested is indicated to have defects, and the process needs to be improved. That is, the design of the semiconductor test structure and the test method of the inter-metal alignment deviation can provide data support for process improvement, and is beneficial to improving the product yield and the product reliability.

The present disclosure also provides a testing method for inter-metal alignment offset, which uses the semiconductor testing structure in any of the above embodiments for testing, as shown in fig. 14, and the testing method may include step S210 to step S240, where:

step S210, measuring the resistance between the first metal wire to be tested and the first conductive test part, or measuring the resistance between the second metal wire to be tested and the second conductive test part.

In some embodiments of the present disclosure, the measuring process of measuring the resistance between the first metal wire to be measured 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 a differential pressure between the first metal wire to be measured 1 and the first conductive test part 31, and the resistance is equal to a ratio of the differential pressure to the current. The preset current may 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 measuring process for measuring the resistance between the second metal wire 2 to be measured and the second conductive test part 32 comprises the steps of applying a preset current to flow between the first test pad 5 and the second test pad 6 connected with the second conductive test part 32, and measuring the pressure difference between the second metal wire 2 to be measured and the second conductive test part 32, wherein the resistance is equal to the ratio of the pressure difference to the current.

Step S220, comparing the resistance with a preset resistance value, and presuming 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 deviation range of the preset resistance value.

The preset resistance value may be a theoretical value or an empirical value of the resistance when no offset phenomenon exists between the first metal wire to be tested 1 and the second metal wire to be tested 2 estimated according to the process conditions. The deviation range of the preset resistance value may be a deviation range of resistance that does not affect the electrical properties of the first and second metal lines to be tested 1 and 2. That is, the deviation range of the preset resistance value is the allowable range of the actual measured value of the resistance from the theoretical value or the empirical value of the resistance.

And step S230, performing slicing treatment on the semiconductor test structure in different directions to obtain microscopic morphology graphs of the semiconductor test structure at slicing positions in different directions.

Step S240, determining that the offset phenomenon exists according to the micro-topography map, and determining the offset direction.

The process of sectioning and determining the offset is substantially identical to that of the previous embodiment, and thus, will not be described again here.

The method for testing the inter-metal alignment offset 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 wire to be tested 1 or the second metal wire to be tested 2, 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 wire to be tested 1 or the second metal wire to be tested 2, compare the breakdown voltage or the resistance with a preset voltage value or a preset resistance value, and infer that the offset phenomenon exists between the first metal wire to be tested 1 and the second metal wire to be tested 2 when the breakdown voltage or the resistance exceeds a preset offset range of the preset voltage value or the preset resistance value, and further determine the offset direction between the second metal wire to be tested 2 and the first metal wire to be tested 1 in a slicing mode. In other words, through a semiconductor test structure in the disclosure, whether an offset (overlay shift) phenomenon exists between the upper and lower metal lines can be detected, a specific direction of the offset can be determined, a window reference of the metal layer offset (overlay shift) is provided for improving the semiconductor process, and the process is monitored, so that the improvement of the process reliability is facilitated. When the breakdown voltage or resistance does not exceed the preset voltage value or the preset deviation range of the preset resistance value, the fact that the first metal wire 1 to be tested and the second metal wire 2 to be tested do not deviate can be directly judged, slicing is not needed, and testing efficiency is high.

It should be noted that although the various steps of the method of testing for inter-metal alignment shifts in the present disclosure are depicted in a particular order in the figures, this does not require or imply that the steps must be performed in that particular order or that all of the illustrated steps must be performed in order to achieve desirable results. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step to perform, and/or one step decomposed into multiple steps to perform, etc.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any adaptations, uses, or adaptations of the disclosure following the general principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. 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.

2. The semiconductor test structure according to claim 1, characterized in that the first metal line to be tested is a serpentine structure, the serpentine structure corresponding to the first metal line to be tested is used as the 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.

3. The semiconductor test structure according to claim 2, 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;

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 , wherein the conductive test structure comprises 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 .

5 . The semiconductor test structure according to claim 3 , wherein the conductive test structure comprises 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 line to be tested comprises a plurality of first comb-shaped structures interconnected with each other, the first comb-shaped structures comprising a first comb ridge and a plurality of first comb teeth located on one side or both sides of the first comb ridge, and the plurality of first comb teeth and the first comb ridge 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 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; characterized in that 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.

9 . The semiconductor test structure according to claim 8 , wherein the conductive test structure comprises 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 comprises 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 comprises 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-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, wherein the first conductive test portion is a serpentine structure, 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.

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 adopts the semiconductor test 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 the alignment offset between metal layers according to claim 15 is characterized in that the 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 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 the alignment offset between metal layers according to claim 15 is characterized in that 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.

18. A method for testing metal layer alignment deviation, characterized in that the method adopts the semiconductor test structure according to any one of claims 1 to 14 for testing; the 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;

19. The method for testing the alignment offset between metal layers according to claim 18 is 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 the alignment offset between metal layers according to claim 18 is characterized in that 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.