Test structure and test method

Abstract

A test structure and test method are disclosed. The structure includes: a first interconnection structure comprising a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion, the first comb tooth portion being electrically connected to a portion of the first metal wire; a second interconnection structure comprising a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion, the second comb tooth portion and the first comb tooth portion being arranged intersecting each other, and the second comb tooth portion being electrically connected to the remaining first metal wire; a third interconnection structure comprising a first interconnection layer forming a series path for adjacent second metal wires, a second interconnection layer located on the same side as the second comb handle portion, and a third interconnection layer located on the same side as the first comb handle portion, the first interconnection layer being electrically connected to the second metal wire, the second interconnection layer being electrically connected to the second metal wire closest to the second comb handle portion, and the third interconnection layer being electrically connected to the second metal wire closest to the first comb handle portion. The test structure has two test functions, saving the area occupied by the test structure.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a test structure and test method. Background Technology

[0002] In advanced BEOL process nodes, as the area continues to shrink and with the introduction of SAQP process, a large number of metal cut processes will occur. The reliability of metal cut process is becoming a key factor affecting product yield. Therefore, detailed monitoring of the health of metal cut process is becoming increasingly important. Common metal cut process failure modes include cut missing and overcut.

[0003] To fully monitor the health of the metal cut process and simulate various situations that may occur in a real chip, it is often necessary to introduce a large number of test structures to cover all possible scenarios.

[0004] Currently, the development of test structures still needs improvement. Summary of the Invention

[0005] The problem solved by the embodiments of the present invention is to provide a test structure and test method, which is beneficial to improving the performance of the test structure.

[0006] To address the aforementioned problems, this invention provides a test structure comprising: a first metal wire arranged in a matrix along a first direction and a second direction, wherein the first direction and the second direction are perpendicular to each other; a second metal wire extending along the first direction and arranged parallel to each other along the second direction on both sides of the first metal wire; a first interconnection structure comprising a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion, wherein the first comb tooth portion is located at the top of the first metal wire and the second metal wire and spans across the first metal wire and the second metal wire, wherein the first comb tooth portion is electrically connected to a portion of the first metal wire, and the first comb handle portion is used as a first test signal terminal; and a second interconnection structure comprising a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion, wherein the second comb tooth portion is located on the second metal wire and the second metal wire. The second metal wire is located at the top of the first metal wire and crosses the second metal wire. The second comb teeth are intersecting with the first comb teeth and are electrically connected to the remaining first metal wire. The second comb handle is used as a second test signal terminal. The third interconnection structure includes a first interconnection layer that forms a series path between adjacent second metal wires, a second interconnection layer located on the same side as the second comb handle, and a third interconnection layer located on the same side as the first comb handle. The first interconnection layer is located at the top of adjacent second metal wires and is electrically connected to the second metal wire. The second interconnection layer is electrically connected to the second metal wire closest to the second comb handle and is used as a third test signal terminal. The third interconnection layer is electrically connected to the second metal wire closest to the first comb handle and is used as a fourth test signal terminal.

[0007] Optionally, along the extension direction of the second metal wire, the second metal wire includes a beginning end and an end end, and the first interconnect layer is separately disposed at the beginning end and the end end of the second metal wire, forming a series path between adjacent second metal wires.

[0008] Optionally, the third interconnect layer is an integral structure with the first comb handle portion, and one of the plurality of first comb teeth portions is electrically connected to the second metal wire closest to the first comb handle portion.

[0009] Optionally, along the first direction, the first comb tooth portion electrically connected to the second metal wire is located above the end position of the second metal wire and is opposite to the first interconnect layer closest to the first comb handle portion.

[0010] Optionally, the test structure further includes a third through-hole interconnect structure located between one of the plurality of first comb teeth and the second metal wire closest to the first comb handle, wherein the first comb teeth and the second metal wire closest to the first comb handle are electrically connected through the third through-hole interconnect structure.

[0011] Optionally, the test structure further includes: a first through-hole interconnect structure located between the second metal wire and the first interconnect layer, wherein the first interconnect layer is electrically connected to the second metal wire through the first through-hole interconnect structure.

[0012] Optionally, the test structure further includes: a second through-hole interconnect structure located between the first comb tooth portion and the first metal wire, between the first comb tooth portion and the first comb handle portion, between the second comb tooth portion and the first metal wire, and between the second comb tooth portion and the second comb handle portion.

[0013] Optionally, along the first direction, the distance between the first comb tooth portion and its adjacent second comb tooth portion is 3 nanometers to 130 nanometers.

[0014] Optionally, along the second direction, the distance between the first metal line and its adjacent second metal line is 3 nanometers to 200 nanometers.

[0015] Optionally, along the second direction, the distance between the second comb handle portion and the second interconnect layer is 3 nanometers to 10,000 nanometers.

[0016] Optionally, along the first direction, the distance between adjacent first metal lines is 10 nanometers to 10,000 nanometers.

[0017] Optionally, the first test signal terminal and the second test signal terminal are used to measure the current value between adjacent first metal lines; the fourth test signal terminal and the third test signal terminal are used to measure the resistance value of the series path.

[0018] Accordingly, this embodiment of the invention also provides a testing method, including: providing the test structure provided in this embodiment of the invention; measuring the current value between the first test signal terminal and the second test signal terminal, and determining whether adjacent first metal wires are short-circuited based on the current value; measuring the resistance value between the fourth test signal terminal and the third test signal terminal, and determining whether the series path is open based on the resistance value.

[0019] Optionally, the step of determining whether adjacent first metal lines are short-circuited includes: if the current value is 0, then it is determined that adjacent first metal lines are not short-circuited; if the current value is greater than 0, then it is determined that adjacent first metal lines are short-circuited.

[0020] Optionally, the step of determining whether the series path is open includes: if the difference between the resistance value and the normal resistance value of the series path is within the normal range, then the series path is determined not to be open; if the difference between the resistance value and the normal resistance value of the series path is outside the normal range, then the series path is determined to be open.

[0021] Optionally, the normal range value is between 0.2Ω and 20Ω.

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

[0023] This invention provides a test structure. A first interconnect structure includes a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion. The first comb tooth portion is located at the top of the first metal wire and a second metal wire and spans across the first and second metal wires. The first comb tooth portion is electrically connected to a portion of the first metal wire. The first comb handle portion serves as a first test signal terminal. A second interconnect structure includes a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion. The second comb tooth portion is located at the top of the second metal wire and a second metal wire and spans across the first and second metal wires. The second comb tooth portion and the first comb tooth portion are intersected, and the second comb tooth portion is electrically connected to the remaining first metal wire. The second comb handle portion serves as a second test signal terminal. This means that the first comb tooth portion, the portion of the first metal wire electrically connected to the first comb tooth portion, and the second comb tooth portion and the remaining first metal wire electrically connected to the second comb tooth portion can form a test path. Measurements are taken through the first test signal terminal and the second test signal terminal. The current value of the test path is measured to determine whether the first metal wire is short-circuited. Simultaneously, the third interconnect structure includes a first interconnect layer forming a series path between adjacent second metal wires, a second interconnect layer located on the same side as the second comb handle, and a third interconnect layer located on the same side as the first comb handle. The first interconnect layer is located on top of adjacent second metal wires and is electrically connected to them. The second interconnect layer is electrically connected to the second metal wire closest to the second comb handle. The second interconnect layer serves as a third test signal terminal. The third interconnect layer is electrically connected to the second metal wire closest to the first comb handle and serves as a fourth test signal terminal. The resistance value of the series path is measured through the third and fourth test signal terminals to determine whether the second metal wire is damaged. In other words, the test structure, while sharing the first and second metal wires, has both the function of determining whether the first metal wire is short-circuited and the function of determining whether the series path is open-circuited, giving the same test structure two testing functions and saving the area occupied by the test structure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an embodiment of the test structure of the present invention;

[0025] Figure 2 This is a flowchart of the steps of an embodiment of the testing method of the present invention. Detailed Implementation

[0026] The performance of current test structures needs improvement. To fully monitor the health of the Metal Cut process, test structures are introduced to cover various possible scenarios in the Metal Cut process. The most common scenarios in the Metal Cut process are Cut Missing (meaning that the metal line that should be cut is not completely cut) and Overcut (meaning that not only the metal line that should be cut is cut, but also the normal metal lines around the cut metal line are cut). However, there is a separate test structure for Cut Missing and another for Overcut. The test structures are all located in the dicing area of ​​the wafer. Since each test structure only has one test function, the area occupied by the test structure on the wafer is too large, which in turn reduces the area occupied by the remaining chip area on the wafer.

[0027] To address the technical problem, this invention provides a test structure, comprising: a first metal wire arranged in a matrix along a first direction and a second direction, wherein the first direction and the second direction are perpendicular to each other; a second metal wire extending along the first direction and arranged parallel to each other along the second direction on both sides of the first metal wire; a first interconnection structure including a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion, wherein the first comb tooth portion is located at the top of the first metal wire and the second metal wire and spans across the first metal wire and the second metal wire, wherein the first comb tooth portion is electrically connected to a portion of the first metal wire, and the first comb handle portion is used as a first test signal terminal; and a second interconnection structure including a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion, wherein the second comb tooth portion is located on the second metal wire. The second comb tooth portion is located at the top of the second metal wire and spans across the first and second metal wires. The second comb tooth portion is intersected with the first comb tooth portion and electrically connected to the remaining first metal wire. The second comb handle portion is used as a second test signal terminal. The third interconnection structure includes a first interconnection layer that forms a series path between adjacent second metal wires, a second interconnection layer located on the same side as the second comb handle portion, and a third interconnection layer located on the same side as the first comb handle portion. The first interconnection layer is located at the top of adjacent second metal wires and electrically connected to the second metal wires. The second interconnection layer is electrically connected to the second metal wire closest to the second comb handle portion. The second interconnection layer is used as a third test signal terminal. The third interconnection layer is electrically connected to the second metal wire closest to the first comb handle portion. The third interconnection layer is used as a fourth test signal terminal.

[0028] In the test structure provided by this embodiment of the invention, the first interconnection structure includes a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion. The first comb tooth portion is located at the top of the first metal wire and the second metal wire and spans across the first metal wire and the second metal wire. The first comb tooth portion is electrically connected to a portion of the first metal wire. The first comb handle portion is used as a first test signal terminal. The second interconnection structure includes a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion. The second comb tooth portion is located at the top of the second metal wire and the second metal wire and spans across the first metal wire and the second metal wire. The second comb tooth portion and the first comb tooth portion are arranged intersecting each other, and the second comb tooth portion is electrically connected to the remaining first metal wire. The second comb handle portion is used as a second test signal terminal. This means that the first comb tooth portion, the portion of the first metal wire electrically connected to the first comb tooth portion, and the second comb tooth portion and the remaining first metal wire electrically connected to the second comb tooth portion can form a test path, through which the first test signal is transmitted. The first interconnection structure measures the current value of the test path at the first and second test signal terminals to determine whether the first metal wire is short-circuited. Simultaneously, the third interconnection structure includes a first interconnection layer forming a series path between adjacent second metal wires, a second interconnection layer located on the same side as the second comb handle, and a third interconnection layer located on the same side as the first comb handle. The first interconnection layer is located on top of adjacent second metal wires and is electrically connected to them. The second interconnection layer is electrically connected to the second metal wire closest to the second comb handle. The second interconnection layer serves as a third test signal terminal. The third interconnection layer is also electrically connected to the second metal wire closest to the first comb handle and serves as a fourth test signal terminal. By measuring the resistance value of the series path through the third and fourth test signal terminals, the damage to the second metal wire can be determined. In other words, the test structure has both the function of determining whether the first metal wire is short-circuited and the function of determining whether the series path is open-circuited, enabling the same test structure to perform two test functions and saving the area occupied by the test structure.

[0029] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of an embodiment of the test structure of the present invention.

[0031] The test structure includes: a first metal wire 107, along a first direction (e.g., Figure 1 (as shown in the X direction) and the second direction (as shown in the X direction) Figure 1 The first direction (as shown in the Y direction) is arranged in a matrix, and the first direction (as shown in the Y direction) is arranged in a matrix. Figure 1 (as shown in the X direction) and the second direction (as shown in the X direction) Figure 1The second metal wire 106 is perpendicular to the first direction (as shown in the Y direction); the second metal wire 106 is perpendicular to the first direction (as shown in the Y direction). Figure 1 Extending along the X direction and along the second direction (as shown in the middle X direction) and as shown in the second direction (e.g. Figure 1 The first interconnection structure 102 includes a first comb handle portion 100 and a first comb tooth portion 101 electrically connected to the first comb handle portion 100. The first comb tooth portion 101 is located on top of the first metal wire 107 and the second metal wire 106 and spans across the first metal wire 107 and the second metal wire 106. The first comb tooth portion 101 is electrically connected to a portion of the first metal wire 107. The first comb handle portion 100 is used as a first test signal terminal 100A. The second interconnection structure 115 includes a second comb handle portion 111 opposite to the first comb handle portion 100 and a second comb tooth portion 112 electrically connected to the second comb handle portion 111. The second comb tooth portion 112 is located on top of the second metal wire 106 and the second metal wire 106 and spans across the first metal wire 107 and the second metal wire 106. The second comb tooth portion 112 and the first comb tooth portion 101 are mutually... The second comb teeth 112 are electrically connected to the remaining first metal wires 107, and the second comb handle 111 is used as a second test signal terminal 100B. The third interconnection structure (not shown) includes a first interconnection layer 130 that forms a series path between adjacent second metal wires 106, a second interconnection layer 110 located on the same side as the second comb handle 111, and a third interconnection layer 103 located on the same side as the first comb handle 100. The first interconnection layer 130 is located on top of adjacent second metal wires 106 and is electrically connected to the second metal wires 106. The second interconnection layer 110 is electrically connected to the second metal wire 106 closest to the second comb handle 111 and is used as a third test signal terminal 100C. The third interconnection layer 103 is electrically connected to the second metal wire 106 closest to the first comb handle 100 and is used as a fourth test signal terminal 100D.

[0032] It should be noted that the first comb tooth 101, the first metal wire 107 electrically connected to the first comb tooth 101, the second comb tooth 112, and the remaining first metal wire 107 electrically connected to the second comb tooth 112 can form a test path. The current value of the test path is measured by the first test signal terminal 100A and the second test signal terminal 100B to determine whether the first metal wire 107 is short-circuited. At the same time, the resistance value of the series path is measured by the third test signal terminal 100C and the fourth test signal terminal 100D to determine whether the second metal wire 106 is damaged. In other words, the test structure has both the function of determining whether the first metal wire 107 is short-circuited and the function of determining whether the series path is open-circuited, so that the same test structure has two test functions, saving the area occupied by the test structure.

[0033] In order to fully monitor the health of the Metal cut process, a test structure is introduced to cover various situations that may occur in the Metal cut process, which means that the health of the Metal cut process is monitored through the test structure.

[0034] Specifically, the test structure is set in the dicing area of ​​the wafer.

[0035] The first metal wire 107 is in the first direction (e.g.) Figure 1 (as shown in the X direction) and the second direction (as shown in the X direction) Figure 1 The matrix arrangement is shown in the Y direction, and the first direction (as shown in the image) is as follows: Figure 1 (as shown in the X direction) and the second direction (as shown in the X direction) Figure 1 (as shown in the Y direction) are perpendicular.

[0036] The first metal line 107 is the metal line that has been metal-cut in the test structure. The first metal line 107 is used to monitor whether a cut missing phenomenon occurs in the metal-cut process.

[0037] Specifically, "cut missing" refers to the fact that the metal wire that should have been cut was not completely cut off.

[0038] It should be noted that along the first direction (e.g.) Figure 1 As shown in the X direction, the distance D1 between adjacent first metal lines 107 should not be too large or too small. Figure 1 As shown in the X direction), if the distance D1 between adjacent first metal lines 107 is too large, the area occupied by the test structure will be too large, resulting in an excessively large wafer dicing area. Consequently, the area reserved for the chip area in the wafer will be too small, leading to a significant reduction in the economic value of the wafer. Along the first direction (as shown in the X direction), Figure 1(As shown in the X direction), if the distance D1 between adjacent first metal lines 107 is too small, the process window for cutting the first metal lines 107 in the Metal cut process will be too small, increasing the difficulty of cutting the first metal lines 107. Simultaneously, a small distance between adjacent first metal lines 107 also increases the probability of short circuits between them, thus affecting the accuracy of the test results during the measurement of the test structure. Therefore, in this embodiment, along the first direction (e.g., as shown in the X direction), Figure 1 (As shown in the X direction), the distance D1 between adjacent first metal lines 107 is 10 nanometers to 10,000 nanometers.

[0039] As an example, the material of the first metal wire 107 includes copper.

[0040] In this embodiment, the second metal wire 106 is along the first direction (e.g., Figure 1 Extending along the X direction and along the second direction (as shown in the middle X direction) and as shown in the second direction (e.g. Figure 1 (As shown in the Y direction) are arranged in parallel on both sides of the first metal line 107 at intervals.

[0041] By setting second metal lines 106 on both sides of the first metal line 107, it is determined whether an overcut phenomenon occurs in the metal cut process, resulting in the second metal line 106 being completely or partially cut off.

[0042] Overcut refers to not only cutting off the metal wire that needs to be cut, but also cutting off the normal metal wire around the cut metal wire.

[0043] It should be noted that along the second direction (e.g.) Figure 1 As shown in the Y direction), the distance D2 between the first metal wire 107 and its adjacent second metal wire 106 should not be too large or too small. Figure 1 As shown in the Y direction), if the distance D2 between the first metal line 107 and its adjacent second metal line 106 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Consequently, the area reserved for the chip area in the wafer will be too small, thus greatly reducing the economic value of the wafer; along the second direction (as shown in the Y direction), if the distance D2 between the first metal line 107 and its adjacent second metal line 106 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Figure 1(As shown in the Y direction), if the distance D2 between the first metal wire 107 and its adjacent second metal wire 106 is too small, the process window for cutting the first metal wire 107 in the metal cut process will be too small, increasing the difficulty of cutting the first metal wire 107. Simultaneously, in the metal cut process, the probability of the second metal wires 106 on both sides of the first metal wire 107 being incorrectly cut will also increase, meaning that overcutting is likely to occur. Therefore, in this embodiment, along the second direction (as shown in the Y direction), Figure 1 (As shown in the Y direction), the distance D2 between the first metal line 107 and its adjacent second metal line 106 is 3 nanometers to 200 nanometers.

[0044] As an example, the material of the second metal wire 106 includes copper.

[0045] The first interconnect structure 102 is electrically connected to a portion of the first metal lines 107, enabling the first interconnect structure 102 to form a test path with the second interconnect structure 115 and the remaining first metal lines 107 electrically connected to the second interconnect structure 115. Specifically, as shown... Figure 1 As shown, along the first direction (e.g.) Figure 1 (As shown in the X direction), adjacent first metal lines 107 are spaced apart. One of the two spaced first metal lines 107 is electrically connected to the first interconnect structure 102, and the other is electrically connected to the second interconnect structure 115. By measuring the current value between the first interconnect structure 102 and the second interconnect structure 115, it is determined whether there is a short circuit between adjacent first metal lines 107, that is, whether a cut missing phenomenon occurs.

[0046] In this embodiment, the first interconnection structure 102 includes a first comb handle portion 100 and a first comb tooth portion 101 electrically connected to the first comb handle portion 100.

[0047] Specifically, the first comb handle portion 100 is used as a first test signal terminal 100A for connecting an external test signal, and the first interconnection structure 102 has a plurality of first comb teeth portions 101, and the first comb teeth portions 101 are used for electrical connection with a portion of the first metal wire 107.

[0048] It should be noted that the first comb tooth portion 101 being electrically connected to a portion of the first metal wire 107 means that the first comb tooth portion 101 is electrically connected to the first metal wire 107 in the extending direction of the first comb tooth portion 101.

[0049] Specifically, along the first direction (e.g.) Figure 1 As shown in the X direction, the distance D3 between the first comb tooth portion 101 and its adjacent second comb tooth portion 112 should not be too large or too small. Figure 1As shown in the X direction), if the distance D3 between the first comb tooth portion 101 and its adjacent second comb tooth portion 112 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Consequently, the area reserved for the chip area in the wafer will be too small, thus significantly reducing the economic value of the wafer; along the first direction (as shown in the X direction), if the distance D3 between the first comb tooth portion 101 and its adjacent second comb tooth portion 112 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Figure 1 As shown in the X direction, if the distance D3 between the first comb tooth 101 and its adjacent second comb tooth 112 is too small, the probability of the first comb tooth 101 and the second comb tooth 112 short-circuiting each other increases, leading to test structure failure and affecting the accuracy of the test results. Therefore, in this embodiment, along the first direction (as shown in the X direction), Figure 1 (As shown in the X direction), the distance D3 between the first comb tooth 101 and its adjacent second comb tooth 112 is 3 nanometers to 130 nanometers.

[0050] In this embodiment, the material of the first interconnect structure 102 includes one or both of copper and aluminum.

[0051] The second interconnect structure 115 is electrically connected to the remaining first metal line 107, so that the second interconnect structure 115 can form a test path with the first interconnect structure 102 and the portion of the first metal line 107 electrically connected to the first interconnect structure 102. By measuring the current value between the first interconnect structure 102 and the second interconnect structure 115, it can be determined whether there is a short circuit between adjacent first metal lines 107, that is, whether a cut missing phenomenon occurs.

[0052] In this embodiment, the second interconnection structure 115 includes a second comb handle portion 111 and a second comb tooth portion 112 electrically connected to the second comb handle portion 111.

[0053] Specifically, the second comb handle portion 111 is used as the second test signal terminal 100B for connecting an external test signal, and the second interconnection structure 115 has a plurality of second comb teeth portions 112, and the second comb teeth portions 112 are used for electrical connection with the remaining first metal wire 107.

[0054] It should be noted that the second comb tooth portion 112 is used for electrical connection with the remaining first metal wire 107, which means that the second comb tooth portion 112 is electrically connected to the first metal wire 107 in the extending direction of the second comb tooth portion 112.

[0055] In this embodiment, the first comb handle portion 100 is used as the first test signal terminal 100A, and the second comb handle portion 111 is used as the second test signal terminal 100B. The first test signal terminal 100A and the second test signal terminal 100B are used to measure the current value between adjacent first metal wires 107. By judging the magnitude of the current value, it is determined whether the adjacent first metal wires 107 are short-circuited (i.e., cut missing).

[0056] Specifically, if the current value is 0, it is determined that there is no short circuit between adjacent first metal lines 107; if the current value is greater than 0, it is determined that there is a short circuit between adjacent first metal lines 107.

[0057] It should be noted that along the second direction (e.g.) Figure 1 As shown in the Y direction), the distance D4 between the second comb handle portion 111 and the second interconnecting layer 110 should not be too large or too small. Figure 1 As shown in the Y direction), if the distance D4 between the second comb shank portion 111 and the second interconnect layer 110 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Consequently, the area reserved for the chip area in the wafer will be too small, thus greatly reducing the economic value of the wafer; along the second direction (as shown in the Y direction), if the distance D4 between the second comb shank portion 111 and the second interconnect layer 110 is too large, it can easily lead to an excessively large area occupied by the test structure, resulting in an excessively large wafer dicing area. Figure 1 As shown in the Y direction, if the distance D4 between the second comb handle portion 111 and the second interconnect layer 110 is too small, the probability of a short circuit between the second comb handle portion 111 and the second interconnect layer 110 increases, leading to test structure failure and affecting the accuracy of test results. Therefore, in this embodiment, along the second direction (as shown in the Y direction), Figure 1 (As shown in the Y direction), the distance D4 between the second comb handle portion 111 and the second interconnect layer 110 is 3 nanometers to 10,000 nanometers.

[0058] In this embodiment, the material of the second interconnect structure 115 includes one or both of copper and aluminum.

[0059] The third interconnect structure (not shown) forms a series path with multiple second metal lines 106. By measuring the resistance value in the series path, it is determined whether the probability of the second metal lines 106 on both sides of the first metal line 107 being accidentally cut during the metal cut process is high, that is, the overcut phenomenon is likely to occur.

[0060] In this embodiment, the second interconnect layer 110 is used as the third test signal terminal 100C, the third interconnect layer 103 is used as the fourth test signal terminal 100D, and the third test signal terminal 100C and the fourth test signal terminal 100D are used to measure the resistance value of the series path.

[0061] In this embodiment, the third interconnection structure (not shown) includes a first interconnection layer 130, a second interconnection layer 110 located on the same side as the second comb handle portion 111, and a third interconnection layer 103 located on the same side as the first comb handle portion 100.

[0062] Specifically, the first interconnect layer 130 is used to enable adjacent second metal lines 106 to form a series path.

[0063] As an example, along the extension direction of the second metal line 106, the second metal line 106 includes a beginning end and an end end, and the first interconnect layer 130 is separately disposed at the beginning end and the end end of the second metal line 106, forming a series path between adjacent second metal lines 106.

[0064] It should be noted that the first interconnect layer 130 is discretely disposed at the beginning and end of the second metal line 106, so that each second metal line 106 can be in a series path from the beginning to the end. Accordingly, in the subsequent measurement of the resistance value between the fourth test signal terminal 100D and the third test signal terminal 100C, each second metal line 106 can be fully monitored from the beginning to the end, that is, it can be determined whether an overcut phenomenon has occurred in each second metal line 106 from the beginning to the end.

[0065] In this embodiment, the third interconnect layer 103 and the first comb handle portion 100 are integrally structured, and one of the plurality of first comb teeth portions 101 is electrically connected to the second metal wire 106 closest to the first comb handle portion 100.

[0066] It should be noted that the third interconnect layer 103 and the first comb handle portion 100 are an integral structure, such as Figure 1 As shown, the third interconnect layer 103 and the first comb handle 100 share a test signal port. Therefore, the first test signal terminal 100A and the fourth test signal terminal 100D are the same test signal terminal.

[0067] Specifically, the first test signal terminal 100A and the fourth test signal terminal 100D are the same test signal terminal, thereby reducing the number of test signal terminals in the test structure, which further saves the area occupied by the test structure, increases the area of ​​the wafer chip area, and allows more chips to be placed in the wafer.

[0068] It should be noted that one of the multiple first comb teeth 101 is electrically connected to the second metal wire 106 closest to the first comb handle 100. Subsequently, during the process of passing through the resistance value in the series path on both sides of the first test signal terminal 100A and the third test signal terminal 100C, all the second metal wires 106 can be in the path of the series path, thereby determining whether all the second metal wires 106 have experienced an overcut phenomenon, thus improving the performance of the test structure.

[0069] In this embodiment, along the first direction (e.g.) Figure 1 (As shown in the X direction), the first comb tooth portion 101, which is electrically connected to the second metal wire 106, is located above the end position of the second metal wire 106 and is opposite to the first interconnect layer 130 that is closest to the first comb handle portion 100.

[0070] It should be noted that the first comb tooth portion 101, which is electrically connected to the second metal wire 106, is located above the end of the second metal wire 106 and is opposite to the first interconnect layer 130 closest to the first comb handle portion 100. This allows the entire second metal wire 106 closest to the first comb handle portion 100 to be in a series path, thereby enabling the determination of whether the entire second metal wire 106 closest to the first comb handle portion 100 has experienced an overcut phenomenon, thus improving the performance of the test structure.

[0071] In this embodiment, the test structure further includes a third through-hole interconnection structure 122, located between one of the plurality of first comb teeth 101 and the second metal wire 106 closest to the first comb handle 100, wherein the first comb teeth 101 and the second metal wire 106 closest to the first comb handle 100 are electrically connected through the third through-hole interconnection structure 122.

[0072] It should be noted that the third through-hole interconnect structure 122 is used to realize the electrical connection between the first comb tooth portion 101 and the second metal wire 106 closest to the first comb handle portion 100.

[0073] It should also be noted that by setting the third through-hole interconnection structure 122, the second metal wire 106 can be electrically connected to the first comb handle portion 100. Since the first comb handle portion 100 is used as the first test signal terminal 100A, it means that the overcut phenomenon of the second metal wire 106 can be measured through the first comb handle portion 100.

[0074] In this embodiment, the material of the third through-hole interconnect structure 122 includes one or both of aluminum and copper.

[0075] In this embodiment, the test structure further includes: a first through-hole interconnect structure 121, located between the second metal line 106 and the first interconnect layer 130, wherein the first interconnect layer 130 is electrically connected to the second metal line 106 through the first through-hole interconnect structure 121.

[0076] It should be noted that the first through-hole interconnect structure 121 is used to realize the electrical connection between the second metal line 106 and the first interconnect layer 130, so that the first interconnect layer 130 can form a series path with the adjacent second metal line 106.

[0077] In this embodiment, the material of the first through-hole interconnect structure 121 includes one or both of aluminum and copper.

[0078] In this embodiment, the test structure further includes: a second through-hole interconnect structure 120, located between the first comb tooth portion 101 and the first metal wire 107, between the first comb tooth portion 101 and the first comb handle portion 100, between the second comb tooth portion 112 and the first metal wire 107, and between the second comb tooth portion 112 and the second comb handle portion 111.

[0079] Specifically, the second through-hole interconnect structure 120 is used to realize the electrical connection between the first comb tooth portion 101 and the first metal wire 107, the electrical connection between the first comb tooth portion 101 and the first comb handle portion 100, the electrical connection between the second comb tooth portion 112 and the first metal wire 107, and the electrical connection between the second comb tooth portion 112 and the second comb handle portion 111, so that one of the two adjacent first metal wires 107 is connected to the first test signal terminal 100A and the other is connected to the second test signal terminal 100B. Then, by measuring the current value between the first test signal terminal 100A and the second test signal terminal 100B, it is determined whether there is a cutmissing phenomenon between the two adjacent first metal wires 107.

[0080] In this embodiment, the material of the second through-hole interconnect structure 120 includes one or both of aluminum and copper.

[0081] Accordingly, embodiments of the present invention also provide a testing method.

[0082] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the following description is provided in conjunction with... Figures 1 to 2 Specific embodiments of the present invention will be described in detail below. Figure 2 This is a flowchart of the steps of an embodiment of the testing method of the present invention.

[0083] refer to Figure 2 Step S1: Provide the test structure provided in the embodiment of the present invention.

[0084] For a detailed description of the test structure provided in the embodiments of the present invention, please refer to the foregoing description, which will not be repeated here.

[0085] refer to Figure 2 Step S2: Measure the current value between the first test signal terminal and the second test signal terminal, and determine whether the adjacent first metal wires are short-circuited based on the current value.

[0086] The first metal line is the metal line that has been metal-cut in the test structure. The first metal line is used to monitor whether a cut missing phenomenon occurs in the metal-cut process.

[0087] Specifically, "Cut missing" means that the metal wire that should have been cut was not completely cut off, that is, there is a short circuit between adjacent first metal wires.

[0088] In this embodiment, the step of determining whether adjacent first metal lines are short-circuited includes: if the current value is 0, then it is determined that adjacent first metal lines are not short-circuited; if the current value is greater than 0, then it is determined that adjacent first metal lines are short-circuited.

[0089] Specifically, a current value of 0 means that there is a complete break between adjacent first metal lines, and there is no interconnection between adjacent first metal lines; a current value greater than 0 means that there is a path between adjacent first metal lines, which means that the adjacent first metal lines are not completely cut off, that is, there is a short circuit between adjacent first metal lines.

[0090] refer to Figure 2 Step S3: Measure the resistance value between the fourth test signal terminal and the third test signal terminal, and determine whether the series path is open based on the resistance value.

[0091] It should be noted that the second metal wire system is used to determine whether an overcut phenomenon occurs in the metal cut process, resulting in the second metal wire being completely or partially cut.

[0092] Overcut refers to cutting not only the metal wire that needs to be cut, but also the normal metal wires around the cut metal wire, which means that there is a break in the series path formed by the second metal wire.

[0093] In this embodiment, the step of determining whether the series path is open includes: if the difference between the resistance value and the normal resistance value of the series path is within the normal range, then the series path is determined not to be open; if the difference between the resistance value and the normal resistance value of the series path is outside the normal range, then the series path is determined to be open.

[0094] Specifically, if the difference between the resistance value and the normal resistance value of the series circuit is within the normal range, it means that the second metal wire was not damaged in the metal cut process. If the difference between the resistance value and the normal resistance value of the series circuit is outside the normal range, it means that the second metal wire was damaged in the metal cut process, thus indicating that the series circuit formed by the second metal wire has an open circuit.

[0095] As an example, the normal range value is between 0.2Ω and 20Ω.

[0096] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A test structure, characterized in that, include: The first metal wire is arranged in a matrix along a first direction and a second direction, wherein the first direction and the second direction are perpendicular. The second metal wire extends along the first direction and is arranged in parallel and spaced apart on both sides of the first metal wire along the second direction. Along the extension direction of the second metal wire, the second metal wire includes a beginning end and an end end. The first interconnection structure includes a first comb handle portion and a first comb tooth portion electrically connected to the first comb handle portion. The first comb tooth portion is located on top of the first metal wire and the second metal wire and spans the first metal wire and the second metal wire. The first comb tooth portion is electrically connected to a portion of the first metal wire. The first comb handle portion is used as a first test signal terminal. The second interconnection structure includes a second comb handle portion opposite to the first comb handle portion and a second comb tooth portion electrically connected to the second comb handle portion. The second comb tooth portion is located at the top of the second metal wire and the second metal wire and spans the first metal wire and the second metal wire. The second comb tooth portion and the first comb tooth portion are arranged to cross each other, and the second comb tooth portion is electrically connected to the remaining first metal wire. The second comb handle portion is used as a second test signal terminal. The third interconnect structure includes a first interconnect layer that forms a series path between adjacent second metal wires. The first interconnect layer is separately disposed at the beginning and end of the second metal wires, forming a series path between adjacent second metal wires. A second interconnect layer is located on the same side as the second comb handle portion. A third interconnect layer is located on the same side as the first comb handle portion. The first interconnect layer is located on top of the adjacent second metal wires and is electrically connected to the second metal wires. The second interconnect layer is electrically connected to the second metal wire closest to the second comb handle portion. The second interconnect layer is used as a third test signal terminal. The third interconnect layer is electrically connected to the second metal wire closest to the first comb handle portion and is used as a fourth test signal terminal.

2. The test structure as described in claim 1, characterized in that, The third interconnect layer is an integral structure with the first comb handle portion, and one of the plurality of first comb teeth portions is electrically connected to the second metal wire closest to the first comb handle portion.

3. The test structure as described in claim 2, characterized in that, Along the first direction, the first comb tooth portion electrically connected to the second metal wire is located above the end position of the second metal wire and is opposite to the first interconnect layer closest to the first comb handle portion.

4. The test structure as described in claim 2 or 3, characterized in that, The test structure further includes a third through-hole interconnect structure located between one of the plurality of first comb teeth and the second metal wire closest to the first comb handle, wherein the first comb teeth and the second metal wire closest to the first comb handle are electrically connected through the third through-hole interconnect structure.

5. The test structure as described in any one of claims 1 to 3, characterized in that, The test structure further includes: a first through-hole interconnect structure located between the second metal wire and the first interconnect layer, wherein the first interconnect layer is electrically connected to the second metal wire through the first through-hole interconnect structure.

6. The test structure as described in any one of claims 1 to 3, characterized in that, The test structure further includes: a second through-hole interconnect structure located between the first comb tooth portion and the first metal wire, between the first comb tooth portion and the first comb handle portion, between the second comb tooth portion and the first metal wire, and between the second comb tooth portion and the second comb handle portion.

7. The test structure as described in any one of claims 1 to 3, characterized in that, Along the first direction, the distance between the first comb tooth portion and its adjacent second comb tooth portion is 3 nanometers to 130 nanometers.

8. The test structure as described in any one of claims 1 to 3, characterized in that, Along the second direction, the distance between the first metal line and its adjacent second metal line is 3 nanometers to 200 nanometers.

9. The test structure as described in any one of claims 1 to 3, characterized in that, Along the second direction, the distance between the second comb handle portion and the second interconnect layer is 3 nanometers to 10,000 nanometers.

10. The test structure as described in any one of claims 1 to 3, characterized in that, Along the first direction, the distance between adjacent first metal lines is 10 nanometers to 10,000 nanometers.

11. The test structure as described in claim 1, characterized in that, The first test signal terminal and the second test signal terminal are used to measure the current value between adjacent first metal wires. The fourth and third test signal terminals are used to measure the resistance value of the series path.

12. A testing method, characterized in that, include: Provide a test structure as described in any one of claims 1 to 11; Measure the current value between the first test signal terminal and the second test signal terminal, and determine whether the adjacent first metal wires are short-circuited based on the current value. Measure the resistance between the fourth test signal terminal and the third test signal terminal, and determine whether the series path is open based on the resistance value.

13. The test method according to claim 12, characterized in that, The step of determining whether adjacent first metal lines are short-circuited includes: if the current value is 0, then it is determined that adjacent first metal lines are not short-circuited; if the current value is greater than 0, then it is determined that adjacent first metal lines are short-circuited.

14. The test method as described in claim 12, characterized in that, The step of determining whether the series path is open includes: if the difference between the resistance value and the normal resistance value of the series path is within the normal range, then the series path is determined not to be open; if the difference between the resistance value and the normal resistance value of the series path is outside the normal range, then the series path is determined to be open.

15. The test method as described in claim 14, characterized in that, The normal range value is between 0.2Ω and 20Ω.

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