Test structure and test method
By setting plugs on different surfaces of the interconnect layer to be tested, a test path is formed, which solves the problem of difficulty in detecting interconnect layers with a small length in the prior art, improves the robustness and reliability of the test structure, and ensures the accuracy of the detection.
Patent Information
- Application Number
- CN202410077787.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-18
- Publication Date
- 2025-07-18
AI Technical Summary
The test structure and its testing methods in the prior art are difficult to effectively detect the quality of the interconnect layer to be tested with a smaller length, and the robustness and reliability of the test structure are insufficient.
A test structure is designed, including a first interconnection layer and a second interconnection layer arranged on the substrate, the second interconnection layer includes an interconnection layer to be tested, and the plugs are respectively arranged on different surfaces of the interconnection layer to be tested, forming a test path to detect electrical parameters of the interconnection layer to be tested.
It improves the robustness and reliability of the test structure, can effectively detect the interconnect layer to be tested with smaller lengths, increases the process monitoring window, and ensures the accuracy of the test results.
Smart Images
Figure CN120341215A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present invention relate to the field of semiconductor manufacturing, and particularly to a test structure and a test method. Background Art
[0002] With the rapid development of the semiconductor integrated circuit (IC) industry, semiconductor technology has continuously advanced towards smaller process nodes driven by Moore's Law, enabling integrated circuits to develop in the direction of smaller volume, higher circuit precision, and higher circuit complexity.
[0003] During the development of integrated circuits, generally, while the functional density (i.e., the number of internal wiring structures per chip) gradually increases, the geometric size (i.e., the minimum element size that can be produced using process steps) gradually decreases.
[0004] Currently, in the case of continuously shrinking technology nodes, the test structures and test methods in the prior art still need to be improved. Summary of the Invention
[0005] The problem solved by the embodiments of the present invention is to provide a test structure and a test method to improve the performance of the test structure.
[0006] To solve the above problems, embodiments of the present invention provide a test structure, including a first test terminal, a second test terminal, and a test unit. The test unit includes: a substrate; a first interconnect layer disposed above the substrate, the first interconnect layer extending along a second direction; a second interconnect layer disposed above the first interconnect layer, the second interconnect layer extending along a first direction, the first direction intersecting the second direction, the second interconnect layer including a to-be-tested interconnect layer, and the to-be-tested interconnect layer including a first to-be-tested interconnect layer, the first to-be-tested interconnect layer having a first surface and a second surface oppositely disposed along its thickness direction; a third interconnect layer disposed above the first to-be-tested interconnect layer and extending along the second direction, the third interconnect layer including a first sub-interconnect layer; a first plug disposed between the first surface of the first to-be-tested interconnect layer and the first interconnect layer, and electrically connected to the first to-be-tested interconnect layer and the first end of the first interconnect layer respectively; a second plug disposed between the second surface of the first to-be-tested interconnect layer and the first sub-interconnect layer, and electrically connected to the first to-be-tested interconnect layer and the first end of the first sub-interconnect layer respectively; wherein, the second end of the first interconnect layer serves as the first interface of the test unit or is electrically connected to the first interface of the test unit, the second end of the first sub-interconnect layer serves as the second interface of the test unit or is electrically connected to the second interface of the test unit, the first test terminal is electrically connected to the first interface, and the second test terminal is electrically connected to the second interface.
[0007] Optionally, the interconnect layer to be measured further includes a second interconnect layer to be measured that is separated from the first interconnect layer to be measured and arranged at intervals along the second direction; the test unit further includes: a third plug, disposed between the second interconnect layer to be measured and the first sub-interconnect layer, and electrically connected to the first end of the second interconnect layer to be measured and the second end of the first sub-interconnect layer respectively; the second end of the second interconnect layer to be measured serves as the second interface of the test unit or is electrically connected to the second interface of the test unit.
[0008] Optionally, the third interconnect layer further includes a second sub-interconnect layer that is separated from the first sub-interconnect layer and arranged at intervals along the first direction, and the second sub-interconnect layer is located above the second interconnect layer to be measured; the test unit further includes: a fourth plug, disposed between the second interconnect layer to be measured and the second sub-interconnect layer, and electrically connected to the second end of the second interconnect layer to be measured and the first end of the second sub-interconnect layer respectively; the second end of the second sub-interconnect layer serves as the second interface of the test unit or is electrically connected to the second interface of the test unit.
[0009] Optionally, the length of the second interconnect layer to be measured is greater than the length of the first interconnect layer to be measured.
[0010] Optionally, the test unit further includes: an eighth plug, located on the second sub-interconnect layer and electrically connected to the second end of the second sub-interconnect layer, and the eighth plug serves as the second interface of the test unit.
[0011] Optionally, the second interconnect layer further includes a connection interconnect layer that is separated from the interconnect layer to be measured and arranged at intervals along the second direction, and the connection interconnect layer and the interconnect layer to be measured are not adjacent; the third interconnect layer further includes a third sub-interconnect layer that is separated from the first sub-interconnect layer and arranged at intervals along the first direction; the test unit further includes: a fifth plug, disposed between the first interconnect layer and the connection interconnect layer, and electrically connected to the second end of the first interconnect layer and the first end of the connection interconnect layer respectively; a sixth plug, disposed between the connection interconnect layer and the third sub-interconnect layer, and electrically connected to the second end of the connection interconnect layer and the first end of the third sub-interconnect layer respectively; the second end of the third sub-interconnect layer serves as the first interface of the test unit or is electrically connected to the first interface of the test unit.
[0012] Optionally, the test unit further includes: a seventh plug, located on the third sub-interconnect layer and electrically connected to the second end of the third sub-interconnect layer, and the seventh plug serves as the first interface of the test unit.
[0013] Optionally, the test unit further includes: an eighth plug, located on the first sub-interconnection layer and electrically connected to the second end of the first sub-interconnection layer, and the eighth plug serves as the second interface of the test unit.
[0014] Optionally, the number of the test units is multiple, and adjacent test units are connected in series.
[0015] Optionally, the second interfaces and the first interfaces of the respective test units are sequentially connected, so that multiple test units are connected in series between the first test end and the second test end to form a chain structure.
[0016] Optionally, the test structure further includes: a fourth interconnection layer, disposed above the third interconnection layer and extending along the first direction, the fourth interconnection layer includes a separately disposed first connection line, a second connection line, and a third connection line; the first connection line connects the second interfaces and the first interfaces of different test units to enable the test units to be connected in series to form a chain structure; the second connection line connects the first interface of the test unit located at the head end in the chain structure; the third connection line connects the second interface of the test unit located at the tail end in the chain structure.
[0017] Optionally, the first direction is perpendicular to the second direction.
[0018] Optionally, the test unit further includes: a partition structure, disposed at an end of the first to-be-tested interconnection layer along the first direction.
[0019] Optionally, the material of the second interconnection layer includes one or both of copper and aluminum.
[0020] Optionally, along the first direction, the length of the first to-be-tested interconnection layer is greater than or equal to 0.082 micrometers.
[0021] Optionally, along the second direction, the width range of the first to-be-tested interconnection layer is 0.014 micrometers to 0.016 micrometers.
[0022] Correspondingly, an embodiment of the present invention further provides a test method, suitable for being tested by using the test structure provided by the embodiment of the present invention, and the test method includes: applying a first test signal to the first test end and applying a second test signal to the second test end to form a test path between the first test end and the second test end; detecting an electrical parameter value output by the test path, and the electrical parameter value is used to determine whether the to-be-tested interconnection layer meets the quality requirements.
[0023] Optionally, in the step of applying a first test signal to the first test terminal and a second test signal to the second test terminal, the first test signal is at a high potential and the second test signal is at a ground potential, or the first test signal is at a ground potential and the second test signal is at a high potential, and the electrical parameter value is a resistance value.
[0024] Optionally, the method of determining whether the interconnect layer under test meets the quality requirements by using the electrical parameter includes: determining whether the electrical parameter value is greater than a preset value. If so, it is determined that the interconnect layer under test does not meet the quality requirements; otherwise, it is determined that the interconnect layer under test meets the quality requirements.
[0025] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:
[0026] The test structure provided by the embodiment of the present invention includes a second interconnect layer disposed above the first interconnect layer. The second interconnect layer includes an interconnect layer under test. The interconnect layer under test includes a first interconnect layer under test having a first surface and a second surface disposed opposite to each other, a first plug disposed between the first surface of the first interconnect layer under test and the first interconnect layer, and both ends of the first plug are electrically connected to the first surface of the first interconnect layer under test and the first end of the first interconnect layer respectively. A second plug is disposed between the second surface of the first interconnect layer under test and the first sub-interconnect layer, and both ends of the second plug are electrically connected to the second surface of the first interconnect layer under test and the first sub-interconnect layer respectively. Since the first plug and the second plug are respectively disposed on different surfaces of the first interconnect layer under test, only one plug is disposed on any surface of the first interconnect layer under test, reducing the influence of the length of the first interconnect layer under test on the setting of the plug, enabling a test structure to be formed even when the length of the first interconnect layer under test is small, increasing the process monitoring window of the first interconnect layer under test, thereby improving the robustness of the test structure, enabling the test structure to be used for detecting the first interconnect layer under test with a small length, and further improving the reliability of the test structure and the reliability of the test results.
[0027] The test method provided by the embodiment of the present invention is suitable for being tested by using the test structure provided by the embodiment of the present invention, including loading a first test signal on a first test terminal and loading a second test signal on a second test terminal to form a test path between the first test terminal and the second test terminal, and detecting the electrical parameter value output by the test path. Since the first plug and the second plug are respectively arranged on different surfaces of the first interconnect layer to be tested, only one plug is arranged on any surface of the first interconnect layer to be tested, reducing the influence of the length of the first interconnect layer to be tested on the arrangement of the plug, enabling the test structure to be formed even when the length of the first interconnect layer to be tested is small, increasing the process monitoring window of the first interconnect layer to be tested, thereby improving the robustness of the test structure, enabling the test structure to be used for detecting the first interconnect layer to be tested with a small length, and further improving the reliability of the test method and the reliability of the test result. Description of the Drawings
[0028] Figure 1 is a schematic structural diagram of a test structure;
[0029] Figure 2 is a schematic structural diagram of an embodiment of the test structure of the present invention;
[0030] Figure 3 is Figure 2 a schematic cross-sectional structure diagram along AA1;
[0031] Figure 4 is a flowchart corresponding to the test method of the present invention. Detailed Embodiments
[0032] Currently, the performance of the test structure still needs to be improved. In combination with a test structure, the reasons for the performance of the test structure to be improved are analyzed. Figure 1 is a schematic structural diagram of a test structure.
[0033] Refer to Figure 1, the test structure includes: a first test terminal s1, a second test terminal s2, and a test unit 1. The test unit 1 includes: a substrate 10; a first interconnect layer 11 disposed above the substrate 10. The first interconnect layer 11 extends along a first direction x. The first interconnect layer 11 includes an interconnect layer under test 12, and the interconnect layer under test 12 includes a first interconnect layer under test 13; a second interconnect layer 14 disposed above the first interconnect layer under test 13 and extending along a second direction y. The first direction x intersects the second direction y. The second interconnect layer 14 includes a first sub-interconnect layer 15 and a second sub-interconnect layer 16 that are separated from each other and arranged at intervals along the first direction x; a first plug 17 disposed between the first interconnect layer under test 13 and the first sub-interconnect layer 15, and two ends of the first plug 17 are respectively electrically connected to a first end of the first interconnect layer under test 13 and a first end of the first sub-interconnect layer 15; a second plug 18 disposed between the first interconnect layer under test 13 and the second sub-interconnect layer 16, and two ends of the second plug 18 are respectively electrically connected to a second end of the first interconnect layer under test 13 and a first end of the second sub-interconnect layer 16; wherein, a second end of the first sub-interconnect layer 15 serves as a first interface 21 of the test unit 1 or is electrically connected to the first interface 21 of the test unit 1, a second end of the second sub-interconnect layer 16 serves as a second interface 22 of the test unit 1 or is electrically connected to the second interface 22 of the test unit 1, the first test terminal s1 is electrically connected to the first interface 21, and the second test terminal s2 is electrically connected to the second interface 22.
[0034] It has been found through research that, in the case of continuously shrinking technology nodes, due to the short length of the first interconnect layer under test 13, it is difficult to arrange two plugs on the same surface of the first interconnect layer under test 13.
[0035] To solve the above technical problems, an embodiment of the present invention provides a test structure, including a first test terminal, a second test terminal, and a test unit. The test unit includes: a substrate; a first interconnect layer disposed above the substrate, the first interconnect layer extending along a second direction; a second interconnect layer disposed above the first interconnect layer, the second interconnect layer extending along a first direction, the first direction intersecting the second direction, the second interconnect layer including an interconnect layer to be tested, and the interconnect layer to be tested including a first interconnect layer to be tested, the first interconnect layer to be tested having a first surface and a second surface oppositely disposed along its thickness direction; a third interconnect layer disposed above the first interconnect layer to be tested and extending along the second direction, the third interconnect layer including a first sub-interconnect layer; a first plug disposed between the first surface of the first interconnect layer to be tested and the first interconnect layer, and electrically connected to the first surface of the first interconnect layer to be tested and the first end of the first interconnect layer respectively; a second plug disposed between the second surface of the first interconnect layer to be tested and the first sub-interconnect layer, and electrically connected to the second surface of the first interconnect layer to be tested and the first end of the first sub-interconnect layer respectively; wherein, the second end of the first interconnect layer serves as the first interface of the test unit or is electrically connected to the first interface of the test unit, the second end of the first sub-interconnect layer serves as the second interface of the test unit or is electrically connected to the second interface of the test unit, the first test terminal is electrically connected to the first interface, and the second test terminal is electrically connected to the second interface.
[0036] In the test structure provided by the embodiment of the present invention, a second interconnect layer is disposed above the first interconnect layer. The second interconnect layer includes an interconnect layer to be tested. The interconnect layer to be tested includes a first interconnect layer to be tested having a first surface and a second surface oppositely disposed. A first plug is disposed between the first surface of the first interconnect layer to be tested and the first interconnect layer, and both ends of the first plug are electrically connected to the first surface of the first interconnect layer to be tested and the first end of the first interconnect layer respectively. A second plug is disposed between the second surface of the first interconnect layer to be tested and the first sub-interconnect layer, and both ends of the second plug are electrically connected to the second surface of the first interconnect layer to be tested and the first sub-interconnect layer respectively. Since the first plug and the second plug are respectively disposed on different surfaces of the first interconnect layer to be tested, only one plug is disposed on any surface of the first interconnect layer to be tested, reducing the influence of the length of the first interconnect layer to be tested on the setting of the plug, enabling the formation of a test structure even when the length of the first interconnect layer to be tested is small, increasing the process monitoring window of the first interconnect layer to be tested, thereby improving the robustness of the test structure, enabling the test structure to be used for detecting the first interconnect layer to be tested with a small length, and further improving the reliability of the test structure and the reliability of the test result.
[0037] In order to make the above objects, features, and advantages of the embodiments of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings.
[0038] Figure 2 It is a schematic structural diagram of an embodiment of the test structure of the present invention; Figure 3 is Figure 2 A cross-sectional structural diagram along AA1.
[0039] Referring to Figures 2 to 3 , in this embodiment, the test structure includes: a first test terminal S1, a second test terminal S2, and a test unit 50. The test unit 50 includes: a substrate 100; a first interconnect layer 110 disposed above the substrate 100, and the first interconnect layer 110 extends along the second direction Y; a second interconnect layer 120 disposed above the first interconnect layer 110, and the second interconnect layer 120 extends along the first direction X, the first direction X intersects the second direction Y, the second interconnect layer 120 includes a to-be-tested interconnect layer 125, and the to-be-tested interconnect layer 125 includes a first to-be-tested interconnect layer 126, and the first to-be-tested interconnect layer 126 has a first surface 1261 and a second surface 1262 oppositely disposed along its thickness direction; a third interconnect layer 130 disposed above the first to-be-tested interconnect layer 126 and extending along the second direction Y, and the third interconnect layer 130 includes a first sub-interconnect layer 131; a first plug 210 disposed between the first surface 1261 of the first to-be-tested interconnect layer 126 and the first interconnect layer 110, and both ends of the first plug 210 are electrically connected to the first surface 1261 of the first to-be-tested interconnect layer 126 and the first end of the first interconnect layer 110 respectively; a second plug 220 disposed between the second surface 1262 of the first to-be-tested interconnect layer 126 and the first sub-interconnect layer 131, and both ends of the second plug 220 are electrically connected to the second surface 1262 of the first to-be-tested interconnect layer 126 and the first end of the first sub-interconnect layer 131 respectively; wherein, the second end of the first interconnect layer 110 serves as the first interface 310 of the test unit 50 or is electrically connected to the first interface 310 of the test unit 50, the second end of the first sub-interconnect layer 131 serves as the second interface 320 of the test unit 50 or is electrically connected to the second interface 320 of the test unit 50, the first test terminal S1 is electrically connected to the first interface 310, and the second test terminal S2 is electrically connected to the second interface 320.
[0040] Wherein, to clearly show the test structure, Figure 2 and Figure 3 the dielectric layer is omitted in
[0041] The test structure is used to detect whether the to-be-tested interconnect layer 125 meets the quality requirements.
[0042] The first test terminal S1 is used to load a first test signal, and the second test terminal S2 is used to load a second test signal.
[0043] The test unit 50 is used to form a test path together with the first test terminal S1 and the second test terminal S2.
[0044] The substrate 100 is used to provide a process platform for the formation of the test unit 50.
[0045] In this embodiment, the substrate 100 is used to form a field effect transistor.
[0046] The substrate 100 includes a substrate (not shown in the figure), and the material of the substrate can be silicon, germanium, silicon germanide, silicon carbide, gallium arsenide, indium gallium, or other materials. The substrate can also be a silicon-on-insulator substrate or a germanium-on-insulator substrate, etc.
[0047] It should be noted that the substrate can be a planar substrate or a substrate with a channel protrusion.
[0048] In this embodiment, according to the actual process conditions, functional structures can be formed in the substrate 100. For example, semiconductor devices such as MOS field effect transistors can be formed in the substrate 100, and a resistance structure can also be formed. In other embodiments, at least one interlayer metal structure (i.e., Mx layer) can also be formed in the substrate, and the interlayer metal structure can have the same structure as the first interconnect layer 110.
[0049] The first interconnect layer 110 is used to electrically connect to the first surface 1261 of the first interconnect layer 126 to be tested, so that the first test signal is loaded on the first surface 1261 of the first interconnect layer 126 to be tested through the first interconnect layer 110.
[0050] In this embodiment, the material of the first interconnect layer 110 includes one or more of copper, aluminum, and cobalt. As an example, the material of the first interconnect layer 110 is cobalt.
[0051] Cobalt is a conductive material and has the characteristics of low resistivity and corrosion resistance, which is beneficial to reducing the resistance of the test structure and also beneficial to reducing the probability of damage to the first interconnect layer 110 during the formation of the test structure. In other embodiments, the material of the first interconnect layer can also be other suitable conductive materials.
[0052] The second interconnect layer 120 is used to electrically connect to the first interconnect layer 110.
[0053] In this embodiment, the material of the second interconnect layer 120 includes one or two of copper and aluminum. As an example, the material of the second interconnect layer 120 is copper.
[0054] Copper is a conductive material with high conductivity and low resistivity, which is beneficial to reducing the resistance of the test structure. Therefore, during the electrical test of the test structure, it is beneficial to obtain more accurate test results. In other embodiments, the material of the second interconnect layer can also be other suitable conductive materials.
[0055] In this embodiment, the second interconnect layer 120 is a certain layer of metal wires, namely Mn, the first interconnect layer 110 is the metal wires of the layer below this metal layer, namely Mn - 1, and the third interconnect layer 130 is the metal wires of the layer above this metal layer, namely Mn + 1.
[0056] As an example, the second interconnect layer 120 is M1 (the first metal layer). Correspondingly, the first interconnect layer 110 is M0 (the zero - layer metal layer), and the third interconnect layer 130 is M2 (the second metal layer).
[0057] The interconnect layer to be tested 125 is used as the target for electrical performance testing.
[0058] Specifically, the first surface 1261 of the first interconnect layer to be tested 126 is electrically connected to the first interconnect layer 110, and the second surface 1262 of the first interconnect layer to be tested 126 is electrically connected to the first sub - interconnect layer 131, so that a test path is formed in series from the first interconnect layer 110 to the first sub - interconnect layer 131.
[0059] Here, the first surface 1261 refers to the surface facing the substrate 100, and correspondingly, the second surface 1262 refers to the surface facing away from the substrate 100.
[0060] It should be noted that in order to make the length L1 of the first interconnect layer to be tested 126 meet the design rules, along the first direction X, the length L1 of the first interconnect layer to be tested 126 should not be too small. Therefore, in this embodiment, along the first direction X, the length L1 of the first interconnect layer to be tested 126 is greater than or equal to 0.082 micrometers.
[0061] It should also be noted that in order to make the width W1 of the first interconnect layer to be tested 126 meet the design rules, along the second direction Y, the width W1 of the first interconnect layer to be tested 126 should not be too small or too large. Therefore, in this embodiment, along the second direction Y, the width W1 of the first interconnect layer to be tested 126 ranges from 0.014 micrometers to 0.016 micrometers.
[0062] In this embodiment, the interconnect layer to be tested 125 further includes a second interconnect layer to be tested 127 that is separated from the first interconnect layer to be tested 126 and arranged at intervals along the second direction.
[0063] The to-be-tested interconnect layer 125 further includes a second to-be-tested interconnect layer 127 that is separate from the first to-be-tested interconnect layer 126 and arranged at intervals in the second direction, facilitating the simultaneous testing of the first to-be-tested interconnect layer 126 and the second to-be-tested interconnect layer 127. That is to say, the to-be-tested interconnect layers 125 at different positions can be tested simultaneously, which is conducive to reducing the area of the test structure and improving the test efficiency.
[0064] Specifically, the length of the second to-be-tested interconnect layer 127 is greater than the length of the first to-be-tested interconnect layer 126.
[0065] The length of the second to-be-tested interconnect layer 127 being greater than the length of the first to-be-tested interconnect layer 126 facilitates having both the third plug and the fourth plug on the same surface of the second to-be-tested interconnect layer 127.
[0066] In this embodiment, the second interconnect layer 120 further includes a connection interconnect layer 128 that is separate from the to-be-tested interconnect layer 125 and arranged at intervals in the second direction Y, and the connection interconnect layer 128 and the to-be-tested interconnect layer 125 are not adjacent.
[0067] The second interconnect layer 120 further includes a connection interconnect layer 128 that is separate from the to-be-tested interconnect layer 125 and arranged at intervals in the second direction Y, and the connection interconnect layer 128 is used to electrically connect the third sub-interconnect layer and the first interconnect layer 110.
[0068] Moreover, the connection interconnect layer 128 and the to-be-tested interconnect layer 125 not being adjacent is conducive to increasing the distance between the connection interconnect layer 128 and the to-be-tested interconnect layer 125, thereby facilitating reducing the influence of the connection interconnect layer 128 on the to-be-tested interconnect layer 125, further improving the reliability of the test structure, and correspondingly further improving the reliability of the test results.
[0069] The third interconnect layer 130 is used to be electrically connected to the second interconnect layer 120.
[0070] In this embodiment, the material of the third interconnect layer 130 includes one or both of copper and aluminum. As an example, the material of the third interconnect layer 130 is copper. In other embodiments, the material of the third interconnect layer can also be other suitable conductive materials.
[0071] The reason why the material of the third interconnect layer 130 includes one or both of copper and aluminum is similar to the reason why the material of the second interconnect layer 120 includes one or both of copper and aluminum, so it will not be elaborated here.
[0072] The first sub-interconnect layer 131 is used to be electrically connected to the second surface 1262 of the first to-be-tested interconnect layer 126; moreover, the first sub-interconnect layer 131 is also used to electrically connect the first to-be-tested interconnect layer 126 and the second to-be-tested interconnect layer 127.
[0073] In this embodiment, the third interconnect layer 130 further includes a second sub-interconnect layer 132 that is separate from the first sub-interconnect layer 131 and arranged at intervals along the first direction X. The second sub-interconnect layer 132 is located above the second interconnect layer to be tested 127.
[0074] The second sub-interconnect layer 132 is used to electrically connect to the second end of the second interconnect layer to be tested 127, so that the first interconnect layer 110, the first interconnect layer to be tested 126, the first sub-interconnect layer 131, and the second sub-interconnect layer 132 that are connected in sequence are connected in series to form a test path.
[0075] In this embodiment, the third interconnect layer 130 further includes a third sub-interconnect layer 133 that is separate from the first sub-interconnect layer 131 and arranged at intervals along the first direction X.
[0076] The third sub-interconnect layer 133 is used to electrically connect to the connection interconnect layer 128, so that the third sub-interconnect layer 133, the connection interconnect layer 128, the first interconnect layer 110, the first interconnect layer to be tested 126, the first sub-interconnect layer 131, the second interconnect layer to be tested 127, and the second sub-interconnect layer 132 that are connected in sequence are connected in series to form a test path.
[0077] In this embodiment, the first direction X is perpendicular to the second direction Y.
[0078] The first direction X being perpendicular to the second direction Y is beneficial to reducing the difficulty of forming the first interconnect layer 110, the second interconnect layer 120, and the third interconnect layer 130.
[0079] A first plug 210 is provided between the first surface 1261 of the first interconnect layer to be tested 126 and the first interconnect layer 110, and both ends of the first plug 210 are electrically connected to the first surface 1261 of the first interconnect layer to be tested 126 and the first end of the first interconnect layer 110 respectively. A second plug 220 is provided between the second surface 1262 of the first interconnect layer to be tested 126 and the first sub-interconnect layer 131, and both ends of the second plug 220 are electrically connected to the second surface 1262 of the first interconnect layer to be tested 126 and the first sub-interconnect layer 131 respectively. Since the first plug 210 and the second plug 220 are respectively provided on different surfaces of the first interconnect layer to be tested 126, only one plug is provided on any surface of the first interconnect layer to be tested 126, reducing the influence of the length of the first interconnect layer to be tested 126 on the setting of the plug, enabling the formation of a test structure even when the length of the first interconnect layer to be tested 126 is small, increasing the process monitoring window of the first interconnect layer to be tested 126, thereby improving the robustness of the test structure, enabling the test structure to be used for detecting the first interconnect layer to be tested 126 with a small length, and further improving the reliability of the test structure and the reliability of the test results.
[0080] In this embodiment, the material of the first plug 210 includes one or both of copper and tungsten.
[0081] As an example, the first plug 210 is V0, where V0 refers to a conductive plug for electrically connecting M0 and M1. The material of the first plug 210 is tungsten. In other embodiments, the material of the first plug may also be other suitable conductive materials.
[0082] In this embodiment, the material of the second plug 220 includes one or both of copper and tungsten.
[0083] As an example, the second plug 220 is V1, where V1 refers to a conductive plug for electrically connecting M1 and M2. The material of the second plug 220 is copper.
[0084] Correspondingly, in this embodiment, the test unit 50 further includes: a third plug 230 disposed between the second interconnect layer to be tested 127 and the first sub-interconnect layer 131, and both ends of the third plug 230 are electrically connected to the first end of the second interconnect layer to be tested 127 and the second end of the first sub-interconnect layer 131 respectively.
[0085] The first sub-interconnect layer 131 and the second interconnect layer to be tested 127 are electrically connected through the third plug 230.
[0086] Specifically, the material of the third plug 230 is similar to that of the second plug 220, and will not be elaborated here.
[0087] Correspondingly, in this embodiment, the test unit 50 further includes: a fourth plug 240 disposed between the second interconnect layer to be tested 127 and the second sub-interconnect layer 132, and both ends of the fourth plug 240 are electrically connected to the second end of the second interconnect layer to be tested 127 and the first end of the second sub-interconnect layer 132 respectively.
[0088] The second interconnect layer to be tested 127 and the second sub-interconnect layer 132 are electrically connected through the fourth plug 240.
[0089] Specifically, the material of the fourth plug 240 is similar to that of the second plug 220, and will not be elaborated here.
[0090] Correspondingly, in this embodiment, the test unit 50 further includes: a fifth plug 250 disposed between the first interconnect layer 110 and the connection interconnect layer 128, and both ends of the fifth plug 250 are electrically connected to the second end of the first interconnect layer 110 and the first end of the connection interconnect layer 128 respectively; a sixth plug 260 disposed between the connection interconnect layer 128 and the third sub-interconnect layer 133, and both ends of the sixth plug 260 are electrically connected to the second end of the connection interconnect layer 128 and the first end of the third sub-interconnect layer 133 respectively.
[0091] The first interconnect layer 110 and the connection interconnect layer 128 are electrically connected through the fifth plug 250, and the connection interconnect layer 128 and the third sub-interconnect layer 133 are electrically connected through the sixth plug 260.
[0092] Specifically, the materials of the fifth plug 250 and the sixth plug 260 are similar to those of the second plug 220, which will not be elaborated here.
[0093] In this embodiment, the test unit 50 further includes: a seventh plug 270, located on the third sub-interconnect layer 133 and electrically connected to the second end of the third sub-interconnect layer 133. The seventh plug 270 serves as the first interface 310 of the test unit 50.
[0094] The seventh plug 270 is used to electrically connect to the second end of the third sub-interconnect layer 133 and is also used to electrically connect to the first test terminal S1.
[0095] Specifically, the material of the seventh plug 270 is similar to that of the second plug 220, which will not be elaborated here.
[0096] In this embodiment, the test unit 50 further includes: an eighth plug 280, located on the first sub-interconnect layer 131 and electrically connected to the second end of the first sub-interconnect layer 131. The eighth plug 280 serves as the second interface 320 of the test unit 50.
[0097] The eighth plug 280 is used to electrically connect to the second end of the first sub-interconnect layer 131 and is also used to serve as the second interface 320 of the test unit 50.
[0098] Specifically, the material of the eighth plug 280 is similar to that of the second plug 220, which will not be elaborated here.
[0099] In a specific embodiment, the interconnect layer 125 to be measured further includes a second interconnect layer 127 to be measured that is discrete from the first interconnect layer 126 to be measured and arranged at intervals along the second direction Y; the third interconnect layer 130 further includes a second sub-interconnect layer 132 that is discrete from the first sub-interconnect layer 131 and arranged at intervals along the first direction X, and the second sub-interconnect layer 132 is located above the second interconnect layer 127 to be measured; the test unit 50 further includes: a third plug 230 disposed between the second interconnect layer 127 to be measured and the first sub-interconnect layer 131, and two ends of the third plug 230 are respectively electrically connected to the first end of the second interconnect layer 127 to be measured and the second end of the first sub-interconnect layer 131; a fourth plug 240 disposed between the second interconnect layer 127 to be measured and the second sub-interconnect layer 132, and two ends of the fourth plug 240 are respectively electrically connected to the second end of the second interconnect layer 127 to be measured and the first end of the second sub-interconnect layer 132; correspondingly, the test unit 50 further includes: an eighth plug 280 located on the second sub-interconnect layer 132 and electrically connected to the second end of the second sub-interconnect layer 132, and the eighth plug 280 serves as the second interface 320 of the test unit 50.
[0100] The eighth plug 280 is used for electrically connecting to the second end of the second sub-interconnect layer 132.
[0101] The first interface 310 is used for electrically connecting to the first test end S1, and the second interface 320 is used for electrically connecting to the second test end S2.
[0102] As an example, the first interface 310 is used for electrically connecting between the first test end S1 and the third sub-interconnect layer 133, and the second interface 320 is used for electrically connecting between the second test end S2 and the second sub-interconnect layer 132, so that the first test end S1, the third sub-interconnect layer 133, the connection interconnect layer 128, the first interconnect layer 110, the first interconnect layer 126 to be measured, the first sub-interconnect layer 131, the second interconnect layer 127 to be measured, and the second sub-interconnect layer 132 connected in sequence are in series to form a test path (as Figure 2 shown by the arrow direction).
[0103] In this embodiment, the second interconnect layer 120 further includes a connection interconnect layer 128 that is discrete from the interconnect layer 125 to be measured and arranged at intervals along the second direction Y. The connection interconnect layer 128 and the interconnect layer 125 to be measured are not adjacent; the third interconnect layer 130 further includes a third sub-interconnect layer 133 that is discrete from the first sub-interconnect layer 131 and arranged at intervals along the first direction X; the test unit 50 further includes: a fifth plug 250 disposed between the first interconnect layer 110 and the connection interconnect layer 128, and both ends of the fifth plug 250 are electrically connected to the second end of the first interconnect layer 110 and the first end of the connection interconnect layer 128 respectively; a sixth plug 260 disposed between the connection interconnect layer 128 and the third sub-interconnect layer 133, and both ends of the sixth plug 260 are electrically connected to the second end of the connection interconnect layer 128 and the first end of the third sub-interconnect layer 133 respectively; correspondingly, the second end of the third sub-interconnect layer 133 serves as the first interface 310 of the test unit 50 or is electrically connected to the first interface 310 of the test unit 50.
[0104] In this embodiment, the interconnect layer 125 to be measured further includes a second interconnect layer 127 to be measured that is discrete from the first interconnect layer 126 to be measured and arranged at intervals along the second direction Y; the test unit 50 further includes: a third plug 230 disposed between the second interconnect layer 127 to be measured and the first sub-interconnect layer 131, and both ends of the third plug 230 are electrically connected to the first end of the second interconnect layer 127 to be measured and the second end of the first sub-interconnect layer 131 respectively; correspondingly, the second end of the second interconnect layer 127 to be measured serves as the second interface 320 of the test unit 50 or is electrically connected to the second interface 320 of the test unit 50.
[0105] Specifically, the third interconnect layer 130 further includes a second sub-interconnect layer 132 that is discrete from the first sub-interconnect layer 131 and arranged at intervals along the first direction X. The second sub-interconnect layer 132 is located above the second interconnect layer 127 to be measured; the test unit 50 further includes: a fourth plug 240 disposed between the second interconnect layer 127 to be measured and the second sub-interconnect layer 132, and both ends of the fourth plug 240 are electrically connected to the second end of the second interconnect layer 127 to be measured and the first end of the second sub-interconnect layer 132 respectively. Correspondingly, the second end of the second sub-interconnect layer 132 serves as the second interface 320 of the test unit 50 or is electrically connected to the second interface 320 of the test unit 50.
[0106] In this embodiment, the test unit 50 further includes: a partition structure 330 disposed at the end of the first interconnect layer 126 to be measured along the first direction X.
[0107] The partition structure 330 is used to partition the second interconnect layer 120 on both sides thereof in the first direction X, so that the first interconnect layer 126 to be measured is insulated from the second interconnect layer 120 in its extending direction.
[0108] Specifically, the material of the partition structure 330 is an insulating material, including one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxide, silicon carbonitride, and silicon carbon oxynitride.
[0109] In this embodiment, the number of test units 50 is multiple, and adjacent test units 50 are connected in series.
[0110] When the number of test units 50 is multiple, adjacent test units 50 are connected in series. That is to say, multiple interconnect layers 125 to be tested are connected in series in the test path between the first test end S1 and the second test end S2, so that any situation where an interconnect layer 125 to be tested does not meet the quality requirements can be reflected by the electrical parameter value output by the test path, thereby further improving the reliability of the test structure and correspondingly further improving the reliability of the test result.
[0111] Specifically, the second interfaces 320 and the first interfaces 310 of the respective test units 50 are connected in sequence, so that multiple test units 50 are connected in series between the first test end S1 and the second test end S2 to form a chain structure.
[0112] The second interfaces 320 and the first interfaces 310 of the respective test units 50 are connected in sequence, so that multiple test units 50 are connected in series between the first test end S1 and the second test end S2 to form a chain structure, which is beneficial to simplifying the test structure.
[0113] In this embodiment, the test structure further includes: a fourth interconnect layer 140, disposed above the third interconnect layer 130 and extending along the first direction X. The fourth interconnect layer 140 includes a separately disposed first connection line 141, a second connection line 142, and a third connection line 143. The first connection line 141 connects the second interfaces 320 and the first interfaces 310 of different test units 50 to connect the test units 50 in series to form a chain structure. The second connection line 142 connects the first interface 310 of the test unit 50 at the head end in the chain structure. The third connection line 143 connects the second interface 320 of the test unit 50 at the tail end in the chain structure.
[0114] The first connection line 141 of the fourth interconnection layer 140 connects the second interfaces 320 and the first interfaces 310 of different test units 50. The second connection line 142 of the fourth interconnection layer 140 connects the first interfaces 310 of the test units 50 at the head end in the chain structure. The third connection line 143 of the fourth interconnection layer 140 connects the second interfaces 320 of the test units 50 at the tail end in the chain structure, which is beneficial to the connection between the first interfaces 310 of the test units 50 at the head end and the first test end S1, the connection between the second interfaces 320 of the test units 50 at the tail end and the second test end S2, and the connection between the second interfaces 320 and the first interfaces 310 of different test units 50, and has less influence on the first interconnection layer 110, the second interconnection layer 120, and the third interconnection layer 130.
[0115] As an example, the fourth interconnection layer 140 is M3.
[0116] In this embodiment, the test structure further includes: a dielectric layer (not shown in the figure), which is located between the first interconnection layer 110 and the fourth interconnection layer 140.
[0117] The dielectric layer includes an interlayer dielectric (ILD) and an intermetal dielectric layer (IMD).
[0118] The dielectric layer is used to achieve electrical isolation between adjacent interconnection layers.
[0119] Specifically, the material of the dielectric layer is a dielectric material, such as silicon oxide.
[0120] Correspondingly, the present invention also provides a test method, which is suitable for testing using the test structure of the embodiment of the present invention. Figure 4 It is a schematic flow chart corresponding to an embodiment of the test method of the present invention.
[0121] Refer to Figure 4 and in combination with reference to Figures 2 to 3 , perform step S1: Apply a first test signal to the first test end S1 and a second test signal to the second test end S2 to form a test path between the first test end S1 and the second test end S2.
[0122] Since the first plug 210 and the second plug 220 are respectively arranged on different surfaces of the first interconnect layer 126 to be measured, only one plug is arranged on any surface of the first interconnect layer 126 to be measured, reducing the influence of the length of the first interconnect layer 126 to be measured on the arrangement of the plug, enabling a test structure to be formed even when the length of the first interconnect layer 126 to be measured is small, increasing the process monitoring window of the first interconnect layer 126, thereby improving the robustness of the test structure, enabling the test structure to be used for detecting the first interconnect layer 126 to be measured with a small length, and further improving the reliability of the test method and the reliability of the test result.
[0123] In this embodiment, in the step of applying a first test signal to the first test terminal S1 and a second test signal to the second test terminal S2, the first test signal is a high potential, the second test signal is a ground potential, or the first test signal is a ground potential, the second test signal is a high potential, and the electrical parameter value is a resistance value.
[0124] The first test signal is a high potential and the second test signal is a ground potential, or the first test signal is a ground potential and the second test signal is a high potential, so that there is a potential difference between the first test terminal S1 and the second test terminal S2, thereby facilitating the output of the electrical parameter value as a resistance value.
[0125] Reference Figure 4 and in combination with reference Figures 2 to 3 perform step S2: Detect the electrical parameter value output by the test path, and the electrical parameter value is used to determine whether the interconnect layer 125 to be measured meets the quality requirements.
[0126] Since the numerical value of the electrical parameter is different when the interconnect layer 125 to be measured meets the quality requirements and when the interconnect layer 125 to be measured does not meet the quality requirements. Therefore, the electrical parameter value output by the test path can be used to determine whether the interconnect layer 125 to be measured meets the quality requirements.
[0127] Specifically, the method for determining whether the interconnect layer 125 to be measured meets the quality requirements by the electrical parameter includes:
[0128] Perform step S3: Determine whether the electrical parameter value is greater than a preset value.
[0129] Perform step S4: If so, determine that the interconnect layer 125 to be measured does not meet the quality requirements.
[0130] Perform step S5: Otherwise, determine that the interconnect layer 125 to be measured meets the quality requirements.
[0131] In this embodiment, the first test signal is at a high potential, the second test signal is at a grounded potential, and the electrical parameter value is a resistance value; correspondingly, the preset value can be a preset resistance value.
[0132] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.
Claims
1. A test structure, characterized in that, Comprising a first test terminal, a second test terminal, and a test unit, the test unit including: A substrate; A first interconnect layer disposed above the substrate, the first interconnect layer extending in a second direction; A second interconnect layer disposed above the first interconnect layer, the second interconnect layer extending in a first direction, the first direction intersecting the second direction, the second interconnect layer including an interconnect layer under test, and the interconnect layer under test including a first interconnect layer under test, the first interconnect layer under test having a first surface and a second surface oppositely disposed along its thickness direction; A third interconnect layer disposed above the first interconnect layer under test and extending in the second direction, the third interconnect layer including a first sub-interconnect layer; A first plug disposed between the first surface of the first interconnect layer under test and the first interconnect layer, and electrically connected to the first end of the first interconnect layer under test and the first interconnect layer respectively; A second plug disposed between the second surface of the first interconnect layer under test and the first sub-interconnect layer, and electrically connected to the first end of the first interconnect layer under test and the first sub-interconnect layer respectively; Wherein, the second end of the first interconnect layer serves as the first interface of the test unit or is electrically connected to the first interface of the test unit, the second end of the first sub-interconnect layer serves as the second interface of the test unit or is electrically connected to the second interface of the test unit, the first test terminal is electrically connected to the first interface, and the second test terminal is electrically connected to the second interface.
2. The test structure according to claim 1, characterized in that, The interconnect layer under test further includes a second interconnect layer under test that is separated from the first interconnect layer under test and arranged at intervals along the second direction; The test unit further includes: a third plug disposed between the second interconnect layer under test and the first sub-interconnect layer, and electrically connected to the first end of the second interconnect layer under test and the second end of the first sub-interconnect layer respectively; The second end of the second interconnect layer under test serves as the second interface of the test unit or is electrically connected to the second interface of the test unit.
3. The test structure according to claim 2, wherein, The third interconnect layer further includes a second sub-interconnect layer that is separated from the first sub-interconnect layer and arranged at intervals along the first direction, the second sub-interconnect layer being located above the second interconnect layer under test; The test unit further includes: a fourth plug disposed between the second interconnect layer under test and the second sub-interconnect layer, and electrically connected to the second end of the second interconnect layer under test and the first end of the second sub-interconnect layer respectively; The second end of the second sub-interconnect layer serves as the second interface of the test unit or is electrically connected to the second interface of the test unit.
4. The test structure according to claim 3, wherein, The length of the second interconnect layer under test is greater than the length of the first interconnect layer under test.
5. The test structure according to claim 3, wherein The test unit further includes: an eighth plug located on the second sub-interconnect layer and electrically connected to the second end of the second sub-interconnect layer, the eighth plug serving as the second interface of the test unit.
6. The test structure according to claim 1, wherein The second interconnect layer further includes a connection interconnect layer that is separated from the interconnect layer under test and arranged at intervals along the second direction, the connection interconnect layer and the interconnect layer under test not being adjacent; The third interconnect layer further includes a third sub-interconnect layer that is separated from the first sub-interconnect layer and arranged at intervals along the first direction; The test unit further includes: a fifth plug, disposed between the first interconnect layer and the connection interconnect layer, and electrically connected to the second end of the first interconnect layer and the first end of the connection interconnect layer respectively; a sixth plug, disposed between the connection interconnect layer and the third sub-interconnect layer, and electrically connected to the second end of the connection interconnect layer and the first end of the third sub-interconnect layer respectively; The second end of the third sub-interconnect layer serves as the first interface of the test unit or is electrically connected to the first interface of the test unit.
7. The test structure according to claim 6, wherein The test unit further includes: a seventh plug, located on the third sub-interconnect layer and electrically connected to the second end of the third sub-interconnect layer, and the seventh plug serves as the first interface of the test unit.
8. The test structure according to claim 1, wherein, The test unit further includes: an eighth plug, located on the first sub-interconnect layer and electrically connected to the second end of the first sub-interconnect layer, and the eighth plug serves as the second interface of the test unit.
9. The test structure according to any one of claims 1 to 8, characterized in that, The number of the test units is multiple, and adjacent test units are connected in series.
10. The test structure according to claim 9, characterized in that, The second interfaces and the first interfaces of each test unit are connected in sequence, so that multiple test units are connected in series between the first test end and the second test end to form a chain structure.
11. The test structure according to claim 10, wherein The test structure further includes: a fourth interconnect layer, disposed above the third interconnect layer and extending along the first direction, and the fourth interconnect layer includes a first connection line, a second connection line, and a third connection line that are separately disposed; The first connection line connects the second interfaces and the first interfaces of different test units, so that the test units are connected in series to form a chain structure; The second connection line connects the first interface of the test unit located at the head end in the chain structure; The third connection line connects the second interface of the test unit located at the tail end in the chain structure.
12. The test structure according to any one of claims 1 to 8, characterized in that, The first direction is perpendicular to the second direction.
13. The test structure according to any one of claims 1 to 8, characterized in that, The test unit further includes: a partition structure, disposed at the end of the first interconnect layer to be tested along the first direction.
14. The test structure according to any one of claims 1 to 8, characterized in that, The material of the second interconnect layer includes one or both of copper and aluminum.
15. The test structure according to any one of claims 1 to 8, characterized in that, Along the first direction, the length of the first interconnect layer to be tested is greater than or equal to 0.082 microns.
16. The test structure according to any one of claims 1 to 8, characterized in that, Along the second direction, the width range of the first interconnect layer to be tested is from 0.014 microns to 0.016 microns.
17. A testing method, characterized in that, Suitable for testing using the test structure according to any one of claims 1 to 16, the test method includes: Applying a first test signal to the first test end and a second test signal to the second test end to form a test path between the first test end and the second test end; Detecting the electrical parameter value output by the test path, and the electrical parameter value is used to determine whether the interconnect layer to be tested meets the quality requirements.
18. The test method according to claim 17, wherein, In the step of applying a first test signal to the first test terminal and a second test signal to the second test terminal, the first test signal is at a high potential and the second test signal is at a ground potential, or the first test signal is at a ground potential and the second test signal is at a high potential, and the electrical parameter value is a resistance value.
19. The test method according to claim 17, wherein The method for determining whether the interconnect layer under test meets the quality requirements based on the electrical parameter includes: determining whether the electrical parameter value is greater than a preset value. If so, it is determined that the interconnect layer under test does not meet the quality requirements; otherwise, it is determined that the interconnect layer under test meets the quality requirements.