Thermal coupling superposition test structure and test method

Abstract

The invention provides a thermal coupling superposition test structure and method, and the structure comprises a plurality of heating devices which are used for providing heat for an electromigration test; the first interconnection layer is located on the plurality of heating devices, a tested wire is arranged in the first interconnection layer, a projection pattern of the tested wire on the first interconnection layer is a first projection pattern, and a pattern of the heating devices on the first interconnection layer is a second projection pattern, the plurality of second projection graphs surround the first projection graph, and the first projection graph is located on at least one second projection graph; the second interconnection layer is located on the first interconnection layer, a detection wire is arranged in the second interconnection layer, the detection wire is electrically connected with the two ends of the tested wire respectively, and the detection wire is used for obtaining resistance corresponding to the tested wire when the heating devices at different positions are started; the resistance corresponding to the tested wire can be obtained when the heating devices at different positions are started, so that the thermal coupling effect generated on the tested wire when the heating devices are arranged at the different positions of the tested wire can be accurately evaluated, the electromigration of the tested wire can be analyzed, and the application range is wide.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a thermal coupling superposition test structure and a test method. BACKGROUND

[0002] Current induced by a metal line causes electromigration (EM), i.e. movement of metal atoms caused by momentum transfer between electrons passing through the wire and the metal atoms making up the wire. Over time, EM causes hillocks (accumulation of excess metal) and / or voids (depletion of initial metal) to form in the wire, which in turn cause short circuits (hillocks) or open circuits (voids).

[0003] As device sizes continue to shrink, Fin FET technology is becoming more and more common. However, as semiconductor devices are manufactured smaller and smaller, higher circuit densities, greater device currents and higher operating frequencies result in semiconductor integrated circuits (ICs) generating heat, which can result in higher electromigration (EM) risk, so Fin FET designers need to use thermal models to analyze the electromigration of metal lines before signing off the design.

[0004] However, the thermal model for analyzing the electromigration of metal lines still needs to be improved. SUMMARY

[0005] The technical problem solved by the present application is to provide a thermal coupling superposition test structure and a test method, which can obtain the resistance of the test wire corresponding to the heating device turned on at different positions, so as to accurately evaluate the thermal coupling effect of the test wire at different positions with the heating device, realize the analysis of the electromigration thereof, and have a wide range of application.

[0006] To solve the above problems, the present application provides a thermal coupling superposition test structure, comprising: a plurality of heating devices for providing heat for electromigration test; a first interconnection layer located on the plurality of heating devices, the first interconnection layer having a test wire therein, the projection pattern of the test wire on the first interconnection layer being a first projection pattern, the pattern of the heating device on the first interconnection layer being a second projection pattern, a plurality of the second projection patterns surrounding the first projection pattern and the first projection pattern being located on at least one of the second projection patterns; a second interconnection layer located on the first interconnection layer, the second interconnection layer having a detection wire therein, the detection wire being electrically connected to both ends of the test wire, the detection wire being used to obtain the resistance of the test wire corresponding to the heating device turned on at different positions.

[0007] Optionally, the first interconnection layer further has a plurality of first electrical connection lines and a plurality of second electrical connection lines electrically connected to the plurality of heat generating devices, the plurality of first electrical connection lines, the plurality of second electrical connection lines and the tested conductive lines are parallelly distributed along a first direction, the first electrical connection lines, the second electrical connection lines and the tested conductive lines extend along a second direction, the first direction is perpendicular to the second direction.

[0008] Optionally, the second interconnection layer further has a plurality of third electrical connection lines and a plurality of fourth electrical connection lines, the plurality of third electrical connection lines and the plurality of fourth electrical connection lines are parallelly distributed along the second direction, the plurality of third electrical connection lines and the plurality of fourth electrical connection lines extend along the first direction, the third electrical connection lines are connected to the first electrical connection lines through first contact holes, the fourth electrical connection lines are connected to the second electrical connection lines through second contact holes.

[0009] Optionally, the heat generating device comprises a substrate, a gate electrode on the substrate, a source electrode and a drain electrode on two sides of the gate electrode, the first electrical connection line is electrically connected to the gate electrode, the first electrical connection line is connected to two third electrical connection lines through two first contact holes respectively, the second electrical connection line comprises a source electrode electrical connection line electrically connected to the source electrode and a drain electrode electrical connection line electrically connected to the drain electrode.

[0010] Optionally, the plurality of heat generating devices at least comprises a fifth heat generating device under the tested conductive line and a fourth heat generating device and a sixth heat generating device on two sides of the fifth heat generating device along the first direction, the first electrical connection line of the fifth heat generating device has a gap with the first electrical connection line of the fourth heat generating device, the first electrical connection line of the fifth heat generating device has the gap with the first electrical connection line of the sixth heat generating device.

[0011] Optionally, the plurality of heat generating devices at least further comprises a first heat generating device, a second heat generating device and a third heat generating device distributed on one side of the fifth heat generating device along the second direction, the gate electrode of the first heat generating device, the gate electrode of the second heat generating device and the gate electrode of the third heat generating device are electrically connected through one first electrical connection line.

[0012] Optionally, the plurality of heat generating devices at least further comprises a seventh heat generating device, an eighth heat generating device and a ninth heat generating device distributed on the other side of the fifth heat generating device along the second direction, the first electrical connection line of the eighth heat generating device has the gap with the first electrical connection line of the seventh heat generating device, the first electrical connection line of the eighth heat generating device has the gap with the first electrical connection line of the ninth heat generating device.

[0013] Optionally, the first electric connection line of the sixth heating device and the first electric connection line of the ninth heating device share the third electric connection line.

[0014] Optionally, the source electric connection line comprises a first source electric connection line, a second source electric connection line, and a third source electric connection line distributed in parallel along the first direction, the source of the first heating device, the source of the second heating device, and the source of the third heating device share the first source electric connection line, the source of the fourth heating device, the source of the fifth heating device, and the source of the sixth heating device share the second source electric connection line, the source of the seventh heating device, the source of the eighth heating device, and the source of the ninth heating device share the third source electric connection line, the first source electric connection line is connected with the fourth electric connection line on the second heating device, the second source electric connection line is connected with the fourth electric connection line on the fifth heating device, and the third source electric connection line is connected with the fourth electric connection line on the eighth heating device, the fourth electric connection lines on the second heating device, the fifth heating device, and the eighth heating device connected with the source electric connection line are the same electric connection line.

[0015] Optionally, the drain electric connection line comprises a first drain electric connection line, a second drain electric connection line, and a third drain electric connection line distributed in parallel along the first direction, the drain of the first heating device, the drain of the second heating device, and the drain of the third heating device share the first drain electric connection line, the drain of the fourth heating device, the drain of the fifth heating device, and the drain of the sixth heating device share the second drain electric connection line, the drain of the seventh heating device, the drain of the eighth heating device, and the drain of the ninth heating device share the third drain electric connection line, the first drain electric connection line is connected with the fourth electric connection line on the second heating device, the second drain electric connection line is connected with the fourth electric connection line on the fifth heating device, and the third drain electric connection line is connected with the fourth electric connection line on the eighth heating device, the fourth electric connection lines on the second heating device, the fifth heating device, and the eighth heating device connected with the drain electric connection line are the same electric connection line.

[0016] Correspondingly, the application further provides a test method of the thermal coupling superimposed test structure, comprising: providing the thermal coupling superimposed test structure, the thermal coupling superimposed test structure comprising: a plurality of heat generating devices for providing heat for electromigration test; a first interconnection layer on the plurality of heat generating devices, the first interconnection layer having a test wire therein, a projection pattern of the test wire on the first interconnection layer being a first projection pattern, a pattern of the heat generating device on the first interconnection layer being a second projection pattern, the plurality of second projection patterns surrounding the first projection pattern and the first projection pattern being located on at least one second projection pattern; a second interconnection layer on the first interconnection layer, the second interconnection layer having a detection wire therein, the detection wire being electrically connected to both ends of the test wire; turning on the heat generating devices at different positions; applying current at the current end of the detection wire; measuring the voltage at the voltage end of the detection wire; and obtaining the corresponding resistance of the test wire according to the voltage and the current.

[0017] Optionally, the first interconnection layer further has a plurality of first electric connection lines and a plurality of second electric connection lines electrically connected to the plurality of heat generating devices, the plurality of first electric connection lines, the plurality of second electric connection lines and the test wire being distributed in parallel along a first direction, the first electric connection lines, the second electric connection lines and the test wire extending along a second direction, the first direction being perpendicular to the second direction; the second interconnection layer further having a plurality of third electric connection lines and a plurality of fourth electric connection lines, the third electric connection lines and the fourth electric connection lines being distributed in parallel along the second direction, the third electric connection lines and the fourth electric connection lines extending along the first direction, the third electric connection lines being connected to the first electric connection lines through first contact holes, and the fourth electric connection lines being connected to the second electric connection lines through second contact holes.

[0018] Optionally, the several heating devices at least include a fifth heating device located at the bottom of the wire under test, a fourth heating device and a sixth heating device located at both sides of the fifth heating device along the first direction, a first heating device, a second heating device and a third heating device distributed on one side of the fifth heating device along the second direction, and a seventh heating device, an eighth heating device and a ninth heating device distributed on the other side of the fifth heating device along the second direction, the gate of the first heating device, the gate of the second heating device and the gate of the third heating device are electrically connected by a first electrical connection line; the first electrical connection line of the sixth heating device and the first electrical connection line of the ninth heating device share the same third electrical connection line; the second electrical connection line includes a source electrical connection line and a drain electrical connection line, the source electrical connection line includes a first source electrical connection line, a second source electrical connection line and a third source electrical connection line distributed in parallel along the first direction, the source of the first heating device, the source of the second heating device and the source of the third heating device share the same first source electrical connection line, the source of the fourth heating device, the source of the fifth heating device and the source of the sixth heating device share the same second source electrical connection line, the source of the seventh heating device, the source of the eighth heating device and the source of the ninth heating device share the same third source electrical connection line, the first source electrical connection line is connected with the fourth electrical connection line located on the second heating device, the second source electrical connection line is connected with the fourth electrical connection line located on the fifth heating device, and the third source electrical connection line is connected with the fourth electrical connection line located on the eighth heating device; the drain electrical connection line includes a first drain electrical connection line, a second drain electrical connection line and a third drain electrical connection line distributed in parallel along the first direction, the drain of the first heating device, the drain of the second heating device and the drain of the third heating device share the same first drain electrical connection line, the drain of the fourth heating device, the drain of the fifth heating device and the drain of the sixth heating device share the same second drain electrical connection line, the drain of the seventh heating device, the drain of the eighth heating device and the drain of the ninth heating device share the same third drain electrical connection line, the first drain electrical connection line is connected with the fourth electrical connection line located on the second heating device, the second drain electrical connection line is connected with the fourth electrical connection line located on the fifth heating device, and the third drain electrical connection line is connected with the fourth electrical connection line located on the eighth heating device.

[0019] Optionally, when the bottom of the test wire has the heating device, the method for obtaining the resistance corresponding to the test wire comprises: applying a high voltage higher than a threshold voltage to the fifth heating device; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; and obtaining the resistance corresponding to the test wire according to the voltage and the current.

[0020] Optionally, the test wire has opposite first side walls in the first direction, and when any of the first side walls has the heating device, the method for obtaining the resistance corresponding to the test wire comprises: applying a high voltage higher than a threshold voltage to the fourth heating device; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; and obtaining the resistance corresponding to the test wire according to the voltage and the current.

[0021] Optionally, the test wire has opposite second side walls in the second direction, and when any of the second side walls has the heating device, the method for obtaining the resistance corresponding to the test wire comprises: applying a high voltage higher than a threshold voltage to the eighth heating device; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; and obtaining the resistance corresponding to the test wire according to the voltage and the current.

[0022] Optionally, the test wire has opposite first side walls in the first direction and opposite second side walls in the second direction, and the corners formed by the connection of the first side walls and the second side walls, and when any of the corners has the heating device, the method for obtaining the resistance corresponding to the test wire comprises: applying a high voltage higher than a threshold voltage to the seventh heating device; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; and obtaining the resistance corresponding to the test wire according to the voltage and the current.

[0023] Optionally, the test wire has opposite first side walls in the first direction and opposite second side walls in the second direction, and the corners formed by the connection of the first side walls and the second side walls, and when one of the first side walls and any of the corners connected with the first side wall in the first direction both have the heating device, the method for obtaining the resistance corresponding to the test wire comprises: applying a high voltage higher than a threshold voltage to the sixth heating device and the ninth heating device; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; and obtaining the resistance corresponding to the test wire according to the voltage and the current.

[0024] Optionally, the tested wire has opposite first sidewalls in the first direction and opposite second sidewalls in the second direction, and corners are formed at the junctions of the first sidewalls and the second sidewalls, and when one of the second sidewalls and the corner connected with the second sidewall in the second direction both have the heating device, the method for obtaining the corresponding resistance of the tested wire comprises: applying a high voltage higher than a threshold voltage to the first heating device, the second heating device and the third heating device; applying a current at the current end of the detection wire; measuring the voltage at the voltage end of the detection wire; and obtaining the corresponding resistance of the tested wire according to the voltage and the current.

[0025] Optionally, the tested wire has opposite first sidewalls in the first direction and opposite second sidewalls in the second direction, and corners are formed at the junctions of the first sidewalls and the second sidewalls, and when the bottom of the tested wire, the first sidewalls, the second sidewalls and any of the corners all have the heating device, the method for obtaining the corresponding resistance of the tested wire comprises: applying a high voltage higher than a threshold voltage to the first heating device, the second heating device, the third heating device, the fourth heating device, the fifth heating device, the sixth heating device, the seventh heating device, the eighth heating device and the ninth heating device; applying a current at the current end of the detection wire; measuring the voltage at the voltage end of the detection wire; and obtaining the corresponding resistance of the tested wire according to the voltage and the current.

[0026] Compared with the prior art, the technical scheme of the present application has the following advantages:

[0027] In the technical scheme of the heat coupling superposition test structure of the present application, the several heating devices provide heat for electromigration test, the tested wire is located in the first interconnection layer on the heating device, the projection pattern of the tested wire on the first interconnection layer is a first projection pattern, the projection pattern of the heating device on the first interconnection layer is a second projection pattern, and the several second projection patterns surround the first projection pattern and the first projection pattern is located on at least one second projection pattern, that is, the heating devices are arranged at the positions vertically below the tested wire and the positions around the tested wire; the detection wire is electrically connected with the tested wire, and is used for obtaining the corresponding resistance of the tested wire when the heating devices at different positions are turned on, so as to accurately evaluate the heat coupling effect of the heating devices at different positions on the tested wire, and the evaluation result is not limited by the size of the heating device and the distance between the heating device and the tested wire, so that the tested wire can be accurately analyzed by electromigration, and has a wide range of application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1This is a schematic diagram of the thermal coupling model in one embodiment;

[0029] Figure 2 This is a schematic diagram of a thermally coupled superimposed test structure in one embodiment of the present invention;

[0030] Figure 3 for Figure 2 The corresponding circuit diagram;

[0031] Figure 4 This is a schematic diagram of the connection between the detection wire and the test wire in one embodiment of the present invention;

[0032] Figures 5 to 12 In one embodiment of the present invention, the pre-designed layout structure includes different layout units. Detailed Implementation

[0033] As described in the background section, existing thermal models for analyzing electromigration in metal lines still need improvement. This will be explained in detail below with reference to the accompanying figures.

[0034] Please refer to Figure 1 A thermal coupling model includes a test conductor L1, and six heating devices at the edge of the test conductor, namely heating device 1, heating device 2, heating device 3, heating device 4, heating device 5 and heating device 6.

[0035] To simplify the thermal coupling model, the worst-case scenario is considered: all heating devices at the boundary of the tested conductor are activated. Due to thermal radiation, a thermal coupling effect exists between the heating devices and the tested conductor, meaning the heat generated by the heating devices affects the electromigration of the tested conductor. An α-test key is connected to the tested conductor, and the α-test key measures the temperature of each of the six heating devices on the tested conductor.

[0036] The inventors discovered that in the above thermal coupling model, Tsensor = MAX(T Device )*MAX(α), T Device To obtain the temperature from the heating device to the test lead, α is the coupling ratio from the heating device to the test lead. α is related to the size of the heating device and the distance between the test lead and the heating device. Using the formula instead of the highest α can reduce the coupling temperature (Tsensor) between the heating device and the test lead, but without the coupling effect of other devices, the thermal model of the heating device and the test lead will also be underestimated, leading to inaccurate final test data and hindering manufacturers from performing electromigration analysis on the test lead.

[0037] The inventors find that, under the action of thermal effect, electromigration of the tested wire is caused, and the electromigration affects the resistance of the tested wire, so the means of directly testing the temperature on the tested wire is converted to obtaining the corresponding resistance of the tested wire under the thermal effect, specifically, the heat for electromigration test is provided by a plurality of heating devices, the tested wire is located in a first interconnection layer on the heating devices, a projection pattern of the tested wire on the first interconnection layer is a first projection pattern, a projection pattern of the heating devices on the first interconnection layer is a second projection pattern, a plurality of second projection patterns surround the first projection pattern and the first projection pattern is located on at least one second projection pattern, that is, the heating devices are arranged at positions vertically below the tested wire and positions around the tested wire; the detection wire is electrically connected with the tested wire, and is used for obtaining the corresponding resistance of the tested wire when the heating devices at different positions are turned on, so as to accurately evaluate the thermal coupling effect of the heating devices at different positions on the tested wire through the resistance, and thus the electromigration analysis of the tested wire is accurately performed, and the evaluation result is not limited by the size of the heating devices and the distance between the heating devices and the tested wire, and has a wide application range.

[0038] In order to make the above-mentioned purpose, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0039] First, please refer to Figure 2 , Figure 3 and Figure 4 , the thermal coupling superposition test structure includes a plurality of heating devices, a tested wire and a detection wire.

[0040] In the embodiment, a plurality of the heating devices have a first interconnection layer M1, the tested wire 100 is arranged in the first interconnection layer M1, a projection pattern of the tested wire 100 on the first interconnection layer M1 is a first projection pattern, a pattern of the heating devices on the first interconnection layer M1 is a second projection pattern, a plurality of the second projection patterns surround the first projection pattern and the first projection pattern is located on at least one of the second projection patterns; the first interconnection layer M1 has a second interconnection layer M2, the detection wire 101 is arranged in the second interconnection layer M2, the detection wire 101 is electrically connected with both ends of the tested wire 100 respectively, and the detection wire 101 is used for obtaining the corresponding resistance of the tested wire 100 when the heating devices at different positions are turned on.

[0041] In the embodiment, the thermal coupling effect of the heating device on the tested wire 100 is accurately evaluated by obtaining the resistance of the tested wire 100 corresponding to the heating device at different positions, and the evaluation result is not limited by the size of the heating device and the distance between the heating device and the tested wire 100, so that the tested wire 100 is accurately analyzed for electromigration, and the application range is wide.

[0042] In the embodiment, the detection wire 101 includes current terminals S1 and S2, and the current is applied to the tested wire 100 to generate heat, and the voltage is measured through the voltage terminals F1 and F2, and the resistance is calculated, and the temperature rise of the tested wire 100 is calculated through the change of the resistance.

[0043] In the embodiment, the current terminals S1 adopt two current wires to reduce the resistance.

[0044] In the embodiment, the heating device is a transistor, and the heating device provides heat for the electromigration test, which means that the transistor itself generates heat when the transistor works normally, thereby causing the thermal effect of the tested wire 100.

[0045] In other embodiments, the heating device can also be other types of heating devices other than the transistor.

[0046] In the embodiment, the heating device includes a substrate, a gate on the substrate, and a source and a drain on both sides of the gate.

[0047] Specifically, the forming method of the heating device includes: providing a substrate; forming an active region on the substrate; forming a gate on the substrate; and forming the source and the drain in the active region on both sides of the gate.

[0048] In the embodiment, before the gate is formed, a fin is also formed on the substrate, and the gate spans the fin and covers part of the top surface of the fin.

[0049] In the embodiment, Figure 2 In order to express the connection relationship between the first interconnection layer M1 and the second interconnection layer M2 and represent the corresponding heating device by the active region, the contact hole connected by M1 and M2 in the figure should be located between M1 and M2, and in order to display the connection relationship of M1, M2 and the heating device, the contact hole is also represented by a dashed line.

[0050] In the embodiment, the several heating devices at least include nine heating devices, specifically, a first heating device T1, a second heating device T2, a third heating device T3, a fourth heating device T4, a fifth heating device T5, a sixth heating device T6, a seventh heating device T7, an eighth heating device T8 and a ninth heating device T9.

[0051] In other embodiments, the several heating devices are also other numbers of heating devices.

[0052] In the embodiment, the reason that the heating devices are arranged as nine is that all the border areas of the tested wire 100 except the top area are affected by the heating devices, and the nine heating devices can include all the areas affected by the heating devices, so that the electromigration of the tested wire 100 can be analyzed when the heating devices are arranged at any position around the border of the tested wire 100.

[0053] Specifically, the first heating device T1, the second heating device T2 and the third heating device T3 are arranged on one side of the tested wire 100 along the second direction, the seventh heating device T7, the eighth heating device T8 and the ninth heating device T9 are arranged on the other side of the tested wire 100 along the second direction, and the first heating device T1, the second heating device T2, the third heating device T3, the seventh heating device T7, the eighth heating device T8 and the ninth heating device T9 are oppositely arranged; the fourth heating device T4 and the sixth heating device T6 are arranged on opposite sides of the fifth heating device T5 along the first direction, and the tested wire 100 is arranged on the top of the fifth heating device T5.

[0054] In the embodiment, the heating device and the first interconnection layer have a first dielectric layer (not shown in the figure), the first dielectric layer has several contact holes, the several contact holes respectively form electrical connections between the gate of the heating device and the first electrical connection line 102, and form electrical connections between the source of the heating device, the drain of the heating device and the second electrical connection line 103; the first interconnection layer and the second interconnection layer have a second dielectric layer (not shown in the figure), and the first contact hole and the second contact hole are located in the second dielectric layer.

[0055] In the embodiment, the first interconnection layer M1 has a plurality of first electrical connection lines 102 and a plurality of second electrical connection lines 103 electrically connected with a plurality of the heat generating devices, the first electrical connection lines 102, the second electrical connection lines 103 and the tested wire 100 are parallelly distributed along a first direction, and the first electrical connection lines 102, the second electrical connection lines 103 and the tested wire 100 extend along a second direction, the first direction being perpendicular to the second direction.

[0056] In the embodiment, the first direction is Y direction, and the second direction is X direction.

[0057] In the embodiment, the second interconnection layer M2 also has a plurality of third electrical connection lines 104 and a plurality of fourth electrical connection lines 105, the third electrical connection lines 104 and the fourth electrical connection lines 105 are parallelly distributed along the second direction, and the third electrical connection lines 104 and the fourth electrical connection lines 105 extend along the first direction, the third electrical connection lines 104 are connected with the first electrical connection lines 102 through first contact holes (V), and the fourth electrical connection lines 105 are connected with the second electrical connection lines 103 through second contact holes (V).

[0058] In the embodiment, the first electrical connection lines 102 are electrically connected with the gate, the first electrical connection lines 102 are connected with two third electrical connection lines 104 through two first contact holes 104a respectively, and the second electrical connection lines 103 include a source electrode electrical connection line electrically connected with the source electrode and a drain electrode electrical connection line electrically connected with the drain electrode.

[0059] In the embodiment, the first electrical connection lines 102 include a first electrical connection line 102 electrically connected with the gate of the first heat generating device T1, the gate of the second heat generating device T2 and the gate of the third heat generating device T3 (T1 / T2 / T3) a first electrical connection line 102 electrically connected with the gate of the fourth heat generating device T4 (T4) a first electrical connection line 102 electrically connected with the gate of the fifth heat generating device T5 (T5) a first electrical connection line 102 electrically connected with the gate of the sixth heat generating device T6 (T6) a first electrical connection line 102 electrically connected with the gate of the seventh heat generating device T7 (T7) a first electrical connection line 102 electrically connected with the gate of the eighth heat generating device T8 (T8) a first electrical connection line 102 electrically connected with the gate of the ninth heat generating device T9 (T9) .

[0060] In the embodiment, the plurality of third electrical connection lines 104 include a third electrical connection line 104 electrically connected with the first electrical connection line 102 (T1 / T2 / T3) .(T1 / T2 / T3) a first electric connection line 102 (T4) a third electric connection line 104 electrically connected to the first electric connection line 102 (T4) a first electric connection line 102 (T5) a third electric connection line 104 electrically connected to the first electric connection line 102 (T5) a first electric connection line 102 (T6) a first electric connection line 102 (T9) a third electric connection line 104 electrically connected to the first electric connection line 102 (T9 / T6) a first electric connection line 102 (T7) a third electric connection line 104 electrically connected to the first electric connection line 102 (T7) a first electric connection line 102 (T8) a third electric connection line 104 electrically connected to the first electric connection line 102 (T8) .

[0061] In the embodiment, the second electric connection line 103 includes a source electrode electric connection line 103a electrically connected to the source electrode and a drain electrode electric connection line 103b electrically connected to the drain electrode, the fourth electric connection line 105 is connected to the second electric connection line 103 through a second contact hole 104b, and the corresponding middle 8 fourth electric connection lines 105 include fourth drain electrode electric connection lines 105b connected to the drain electrode electric connection lines 103b and fourth source electrode electric connection lines 105a connected to the source electrode electric connection lines 103a. Specifically, the fourth drain electrode electric connection lines 105b with serial numbers 1, 3, 5, and 7 on the left side are connected to the drain electrode electric connection lines 103b, and the fourth source electrode electric connection lines 105a with serial numbers 2, 4, 6, and 8 are connected to the source electrode electric connection lines 103a.

[0062] In the embodiment, the multiple designed source electrode electric connection lines 103a (specifically two), the multiple designed drain electrode electric connection lines 103b (specifically two), the multiple designed fourth source electrode electric connection lines 105a (specifically four), and the multiple designed fourth drain electrode electric connection lines 105b (specifically four) are designed to reduce the resistance of the formed test structure, thereby reducing the heat generation of the test structure, which helps to reduce the heat impact on the detection wire 101, so as to ensure the service life of the detection wire 101.

[0063] In the embodiment, the first electric connection line 102 is connected to two third electric connection lines 104 through two first contact holes 104a, so as to reduce the resistance of the gate electrode.

[0064] In the embodiment, the fifth heat generating device T5 is located below the tested wire 100, and the fourth heat generating device T4 and the sixth heat generating device T6 are located on both sides of the fifth heat generating device T5 along the first direction.

[0065] In the embodiment, the first electric connection line 102 of the fifth heat generating device T5 has a gap 106 with the first electric connection line 102 of the fourth heat generating device T4, and the first electric connection line 102 of the fifth heat generating device T5 has the gap 106 with the first electric connection line 102 of the sixth heat generating device T6.

[0066] In the embodiment, the presence of the gap 106 realizes the design of minimizing the distance between heat generating devices.

[0067] In the embodiment, the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3 are distributed on one side of the fifth heat generating device T5 along the second direction.

[0068] Specifically, the gate of the first heat generating device T1, the gate of the second heat generating device T2 and the gate of the third heat generating device T3 are electrically connected through the first electric connection line 102, and then electrically connected with the third electric connection line 104 through the first electric connection line 102, so as to realize the simultaneous opening and closing of the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3.

[0069] In the embodiment, the seventh heat generating device T7, the eighth heat generating device T8 and the ninth heat generating device T9 are distributed on the other side of the fifth heat generating device T5 along the second direction, the first electric connection line 102 of the eighth heat generating device T8 has the gap 106 with the first electric connection line 102 of the seventh heat generating device T7, and the first electric connection line 102 of the eighth heat generating device T8 has the gap 106 with the first electric connection line 102 of the ninth heat generating device T9.

[0070] In the embodiment, the first electric connection line 102 on the sixth heat generating device T6 and the first electric connection line 102 on the ninth heat generating device T9 share the same third electric connection line 104, so as to realize that the gates of the sixth heat generating device T6 and the ninth heat generating device T9 are connected out through one terminal, thereby realizing the simultaneous control of the opening and closing of the sixth heat generating device T6 and the ninth heat generating device T9.

[0071] In the embodiment, the source electrode connection line 130a includes first source electrode connection line 130a1, second source electrode connection line 130a2, and third source electrode connection line 130a3 which are parallel to each other along the first direction. The source electrode of the first heat generating device T1, the source electrode of the second heat generating device T2, and the source electrode of the third heat generating device T3 share the first source electrode connection line 130a1. The source electrode of the fourth heat generating device T4, the source electrode of the fifth heat generating device T5, and the source electrode of the sixth heat generating device T6 share the second source electrode connection line 130a2. The source electrode of the seventh heat generating device T7, the source electrode of the eighth heat generating device T8, and the source electrode of the ninth heat generating device T9 share the third source electrode connection line 130a3. The first source electrode connection line 130a1 is connected to the fourth source electrode connection line 105a on the second heat generating device T2. The second source electrode connection line 130a2 is connected to the fourth source electrode connection line 105a on the fifth heat generating device T5. The third source electrode connection line 130a3 is connected to the fourth source electrode connection line 105a on the eighth heat generating device T8. The fourth source electrode connection line 105a on the second heat generating device T2, the fifth heat generating device T5, and the eighth heat generating device T8.

[0072] In the embodiment, please refer to Figure 2 The fourth source electrode connection line 105a is designed as multiple lines, specifically four lines, to reduce the resistance of the source electrode.

[0073] In the embodiment, the drain electrode connection line 103b includes the first drain electrode connection line 103b1, the second drain electrode connection line 103b2 and the third drain electrode connection line 103b3 which are parallel to each other along the first direction, the drain electrode of the first heat generating device T1, the drain electrode of the second heat generating device T2 and the drain electrode of the third heat generating device T3 share the first drain electrode connection line 103b1, the drain electrode of the fourth heat generating device T4, the drain electrode of the fifth heat generating device T5 and the drain electrode of the sixth heat generating device T6 share the second drain electrode connection line 103b2, the drain electrode of the seventh heat generating device T7, the drain electrode of the eighth heat generating device T8 and the drain electrode of the ninth heat generating device T9 share the third drain electrode connection line 103b3, the first drain electrode connection line 103b1 is connected to the fourth drain electrode connection line 105b on the second heat generating device T2, the second drain electrode connection line 103b2 is connected to the fourth drain electrode connection line 105b on the fifth heat generating device T5, the third drain electrode connection line 103b3 is connected to the fourth drain electrode connection line 105b on the eighth heat generating device T8, the fourth drain electrode connection line 105b on the second heat generating device T2, the fifth heat generating device T5 and the eighth heat generating device T8 is the same connection line, so that the source electrodes of the first heat generating device T1, the second heat generating device T2, the third heat generating device T3, the fourth heat generating device T4, the fifth heat generating device T5, the sixth heat generating device T6, the seventh heat generating device T7, the eighth heat generating device T8 and the ninth heat generating device T9 are connected to one terminal, and the drain electrodes are also connected to one terminal, so that the number of terminals is reduced.

[0074] In the embodiment, please refer to Figure 2 The fourth drain electrode connection line 105b is designed as multiple lines, specifically four lines, to reduce the resistance of the drain electrode.

[0075] In the embodiment, please refer to Figure 3 The total number of terminals of the thermal coupling superposition test structure is 13, including 6 gate terminals, 1 source terminal, 1 drain terminal, 2 current terminals, 2 voltage terminals and 1 bulk terminal, which greatly reduces the number of terminals.

[0076] Correspondingly, the application also provides a test method of the thermal coupling superposition test structure, including providing the thermal coupling superposition test structure, turning on the heat generating devices at different positions; applying current to the current terminal of the detection wire 101; measuring the voltage of the voltage terminal of the detection wire 101; and obtaining the corresponding resistance of the tested wire 100 according to the voltage and the current.

[0077] In the embodiment, the tested wire 100 includes a bottom, opposite first sidewalls in the first direction, opposite second sidewalls in the second direction, and corners formed at the junction of the first sidewalls and the second sidewalls, and the bottom, the first sidewalls, the second sidewalls, and any of the corners of the tested wire 100 will generate electromigration effect due to the existence of the heating device.

[0078] Therefore, when the heating device exists at different positions around the tested wire 100, how to analyze the electromigration of the tested wire 100 by the above thermal coupling superposition test structure is shown in the following method:

[0079] Please refer to Figure 2 When the heating device exists at the bottom of the tested wire 100, the method for obtaining the corresponding resistance of the tested wire 100 includes: applying a high voltage higher than a threshold voltage to the fifth heating device T5; applying a current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the corresponding resistance of the tested wire 100 according to the voltage and the current.

[0080] Please refer to Figure 2 When the heating device exists at any of the first sidewalls, the method for obtaining the corresponding resistance of the tested wire 100 includes: applying a high voltage higher than a threshold voltage to the fourth heating device T4; applying a current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the corresponding resistance of the tested wire 100 according to the voltage and the current.

[0081] Please refer to Figure 2 When the heating device exists at any of the second sidewalls, the method for obtaining the corresponding resistance of the tested wire 100 includes: applying a high voltage higher than a threshold voltage to the eighth heating device T8; applying a current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the corresponding resistance of the tested wire 100 according to the voltage and the current.

[0082] Please refer to Figure 2 When the heating device exists at any of the corners, the method for obtaining the corresponding resistance of the tested wire 100 includes: applying a high voltage higher than a threshold voltage to the seventh heating device T7; applying a current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the corresponding resistance of the tested wire 100 according to the voltage and the current.

[0083] Please refer to Figure 2When the first side wall and any corner connected with the first side wall in the first direction both have the heating device, the method for obtaining the resistance corresponding to the tested wire 100 comprises: applying high voltage higher than threshold voltage to the sixth heating device T6 and the ninth heating device T9; applying current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the resistance corresponding to the tested wire 100 according to the voltage and the current.

[0084] Please refer to Figure 2 When the second side wall and the corner connected with the second side wall in the second direction both have the heating device, the method for obtaining the resistance corresponding to the tested wire 100 comprises: applying high voltage higher than threshold voltage to the first heating device T1, the second heating device T2 and the third heating device T3; applying current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the resistance corresponding to the tested wire 100 according to the voltage and the current.

[0085] Please refer to Figure 2 When the bottom of the tested wire 100, the first side wall, the second side wall and any corner all have the heating device, the method for obtaining the resistance corresponding to the tested wire 100 comprises: applying high voltage higher than threshold voltage to the first heating device T1, the second heating device T2, the third heating device T3, the fourth heating device T4, the fifth heating device T5, the sixth heating device T6, the seventh heating device T7, the eighth heating device T8 and the ninth heating device T9; applying current to the current end of the detection wire 101; measuring the voltage of the voltage end of the detection wire 101; and obtaining the resistance corresponding to the tested wire 100 according to the voltage and the current.

[0086] In the process of designers from the pre-design layout structure stage to the final design layout, how to use the above thermal coupling superposition test structure to perform electromigration analysis on the tested wire 100 will be specifically described in the following embodiments.

[0087] When the pre-design layout structure comprises the following layout units, please refer to Figure 5, including a heating device 200; a first interconnection layer (not shown in the figure) above the heating device, the first interconnection layer M1 has a test wire 201 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected with the heating device, the heating device is located directly below the test wire 201, the projection pattern of the test wire 201 on the first interconnection layer (not shown in the figure) is a first projection pattern, the projection pattern of the heating device on the first interconnection layer (not shown in the figure) is a second projection pattern, and the first projection pattern is located on the second projection pattern; a second interconnection layer (not shown in the figure) on the first interconnection layer (not shown in the figure).

[0088] It should be noted that the heating device in the pre-design layout structure is the same as the heating device in the thermal coupling superposition test structure, and the schematic layout unit only shows the boundary condition of the test wire without specifically showing the electrical connection relationship of each component in the layout unit.

[0089] For the layout unit, how to use the thermal coupling superposition test structure to analyze the electromigration of the layout unit before determining the final design layout structure, the specific method is as follows: the heating device is located at the bottom of the test wire 201, so the layout unit is equivalent to the situation that only the fifth heating device T5 in the thermal coupling superposition test structure is turned on and other heating devices are turned off, so the method of analyzing the electromigration of the layout unit is: please refer to Figure 2 , applying a high voltage higher than the threshold voltage to the fifth heating device T5 in the thermal coupling superposition test structure; applying a current to the current end of the detection wire; measuring the voltage at the voltage end of the detection wire; according to the voltage and the current, obtaining the corresponding resistance of the test wire, calculating the temperature rise of the test wire through the change of the resistance, and corresponding analyzing the electromigration of the layout unit, when the electromigration does not meet the requirements, adjusting the layout unit so that the layout unit meets the electromigration requirements.

[0090] When the pre-design layout structure includes the following layout unit, please refer to Figure 6 , including a heating device 300; a first interconnection layer (not shown in the figure) above the heating device, the first interconnection layer has a test wire 301 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected with the heating device, the projection pattern of the test wire 301 on the first interconnection layer is a first projection pattern, the projection pattern of the heating device 300 on the first interconnection layer is a second projection pattern, and the first projection pattern is located on the right side of the second projection pattern along the second direction (X).

[0091] The layout unit is equivalent to a situation that the heat generating device is located at the second side wall of the tested wire in the thermal coupling superposition test structure, that is, only the eighth heat generating device T8 is turned on and other heat generating devices are turned off. Therefore, a method for performing electromigration analysis on the layout unit is as follows: a high voltage higher than a threshold voltage is applied to the eighth heat generating device T8 in the thermal coupling superposition test structure; a current is applied to the current end of the detection wire; a voltage at the voltage end of the detection wire is measured; a corresponding resistance of the tested wire is obtained according to the voltage and the current; a temperature rise of the tested wire is calculated through a change in the resistance, so as to correspondingly analyze electromigration of the layout unit. When the electromigration does not meet a requirement, the layout unit is adjusted. After the electromigration meets the requirement, a final design layout structure is formed.

[0092] In other embodiments, the situation that the first projection pattern is located on the left side of the second projection pattern along the second direction also applies.

[0093] When the pre-design layout structure includes the following layout unit, refer to Figure 7 , the layout unit includes the heat generating device 400, the first interconnection layer (not shown in the figure) located above the heat generating device, the first interconnection layer having the tested wire 401 and the first electrical connection line (not shown in the figure) and the second electrical connection line (not shown in the figure) electrically connected to the heat generating device, a projection pattern of the tested wire 401 on the first interconnection layer is a first projection pattern, a projection pattern of the heat generating device on the first interconnection layer is a second projection pattern, and the first projection pattern is located above the second projection pattern along a first direction (Y).

[0094] The layout unit is equivalent to a situation that the heat generating device is located at the second side wall of the tested wire in the thermal coupling superposition test structure, that is, only the eighth heat generating device T8 is turned on and other heat generating devices are turned off. Therefore, a method for performing electromigration analysis on the layout unit is as follows: a high voltage higher than a threshold voltage is applied to the eighth heat generating device T8 in the thermal coupling superposition test structure; a current is applied to the current end of the detection wire; a voltage at the voltage end of the detection wire is measured; a corresponding resistance of the tested wire is obtained according to the voltage and the current; a temperature rise of the tested wire is calculated through a change in the resistance, so as to correspondingly analyze electromigration of the layout unit. When the electromigration does not meet a requirement, the layout unit is adjusted. After the electromigration meets the requirement, a final design layout structure is formed.

[0095] When the pre-design layout structure includes the following layout unit, refer to Figure 8: comprising a heating device 500; a first interconnection layer (not shown in the figure) above the heating device 500, the first interconnection layer having a test wire 501 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected to the heating device 500, a projection pattern of the test wire 501 on the first interconnection layer being a first projection pattern, a projection pattern of the heating device 500 on the first interconnection layer being a second projection pattern, one corner of the first projection pattern and one corner of the second projection pattern being opposite.

[0096] The layout unit is equivalent to a corner of the heating device in the thermal coupling superposition test structure at the junction of the first side wall and the second side wall of the test wire, that is, only the seventh heating device T7 is turned on and other heating devices are turned off, so the method of electromigration analysis of the layout unit is: applying a high voltage higher than the threshold voltage to the seventh heating device T7 in the thermal coupling superposition test structure; applying a current to the current end of the detection wire; measuring the voltage at the voltage end of the detection wire; according to the voltage and current, obtaining the corresponding resistance of the test wire, calculating the temperature rise of the test wire through the change of the resistance, and corresponding analyzing the electromigration of the layout unit, when the electromigration does not meet the requirements, adjusting the layout unit, and forming the final design layout structure after meeting the electromigration requirements.

[0097] When the pre-design layout structure includes the following layout unit, please refer to Figure 9 , comprising a plurality of heating devices 600, including a first heating device 600a and a second heating device 600b; a first interconnection layer (not shown in the figure) above the heating device 600, the first interconnection layer having a test wire 601 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected to the heating device 600, a projection pattern of the test wire 600 on the first interconnection layer being a first projection pattern, a projection pattern of the first heating device 600a on the first interconnection layer being a first sub-projection pattern, a projection pattern of the second heating device 600b on the first interconnection layer being a second sub-projection pattern, the first projection pattern being located on the left side of the first sub-projection pattern along the second direction (X), and one corner of the first projection pattern and one corner of the second sub-projection pattern being opposite.

[0098] The layout unit is equivalent to the case that the heat generating devices are located at the second side wall and the corners connected to the second side wall along the second direction in the thermal coupling superposition test structure, i.e., only the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3 are turned on at the same time, so the method for performing electromigration analysis on the layout unit is: applying a high voltage higher than a threshold voltage to the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3 in the thermal coupling superposition test structure; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; obtaining the corresponding resistance of the tested wire according to the voltage and the current, and calculating the temperature rise of the tested wire through the change of the resistance, thereby predicting the electromigration of the tested wire.

[0099] When the pre-designed layout structure includes the following layout unit, please refer to Figure 10 , including a plurality of heat generating devices 700, including a first heat generating device 700a, a second heat generating device 700b and a third heat generating device 700c; a first interconnection layer (not shown in the figure) located above the heat generating devices, the first interconnection layer has a tested wire 701 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected with the heat generating devices 700, the projection pattern of the tested wire 701 on the first interconnection layer is a first projection pattern, the projection pattern of the first heat generating device 700a on the first interconnection layer is a third sub-projection pattern, the projection pattern of the second heat generating device 700b on the first interconnection layer is a fourth sub-projection pattern, and the projection pattern of the third heat generating device 700c on the first interconnection layer is a fifth sub-projection pattern, the first projection pattern is located below the fourth sub-projection pattern along the first direction, the third sub-projection pattern, the fourth sub-projection pattern and the fifth sub-projection pattern are distributed in parallel along the second direction, and the third sub-projection pattern and the fifth sub-projection pattern are respectively opposite to the corners of the first projection pattern.

[0100] The layout unit is equivalent to the case that the heat generating devices are located at the second side wall and the corners connected to the second side wall along the second direction in the thermal coupling superposition test structure, i.e., only the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3 are turned on at the same time, so the method for performing electromigration analysis on the layout unit is: applying a high voltage higher than a threshold voltage to the first heat generating device T1, the second heat generating device T2 and the third heat generating device T3 in the thermal coupling superposition test structure; applying a current to the current end of the detection wire; through measuring the voltage of the voltage end of the detection wire; obtaining the corresponding resistance of the tested wire according to the voltage and the current, and calculating the temperature rise of the tested wire through the change of the resistance.

[0101] When the pre-design layout structure includes the following layout unit, please refer to Figure 11 : including a plurality of heat generating devices 800, including a first heat generating device 800a, a second heat generating device 800b and a third heat generating device 800c; a first interconnection layer (not shown in the figure) above the heat generating device, the first interconnection layer has a test wire 801 and a first electrical connection line (not shown in the figure) and a second electrical connection line (not shown in the figure) electrically connected with the heat generating device 800, the projection pattern of the test wire 801 on the first interconnection layer is a first projection pattern, the projection pattern of the first heat generating device 800a on the first interconnection layer is a sixth sub-projection pattern, the projection pattern of the second heat generating device 800b on the first interconnection layer is a seventh sub-projection pattern and the projection pattern of the third heat generating device 800c on the first interconnection layer is an eighth sub-projection pattern, the sixth sub-projection pattern, the seventh sub-projection pattern and the eighth sub-projection pattern are distributed in parallel along the first direction (Y), the first projection pattern is located on the right side of the sixth sub-projection pattern along the first direction, and the seventh sub-projection pattern and the eighth sub-projection pattern are respectively opposite to the corners of the first projection pattern.

[0102] For this layout unit, it is equivalent to the case that only the sixth heat generating device T6, the ninth heat generating device T9 and the seventh heat generating device T7 are turned on in the thermal coupling superposition test structure, so the method of electromigration analysis for this layout unit is: applying a high voltage higher than the threshold voltage to the sixth heat generating device T6, the ninth heat generating device T9 and the seventh heat generating device T7 in the thermal coupling superposition test structure; applying a current to the current end of the detection wire; measuring the voltage of the voltage end of the detection wire; according to the voltage and current, obtaining the resistance corresponding to the test wire, and calculating the temperature rise of the test wire through the change of the resistance.

[0103] When the pre-design layout structure includes the following layout unit, please refer to Figure 12: including a plurality of heat generating devices 900, including a first heat generating device 900a, a second heat generating device 900b, a third heat generating device 900c, a fourth heat generating device 900d, a fifth heat generating device 900e, a sixth heat generating device 900f, a seventh heat generating device 900g, an eighth heat generating device 900h, a ninth heat generating device 900i; a first interconnection layer (not shown in the figure) above the heat generating devices, the first interconnection layer having a first electrically connected line (not shown in the figure) and a second electrically connected line (not shown in the figure) electrically connected with the heat generating devices 900 and a tested wire 901, a projection pattern of the tested wire 901 on the first interconnection layer being a first projection pattern, a pattern of the heat generating devices 900 on the first interconnection layer being a second projection pattern, several second projection patterns surrounding the first projection pattern and the first projection pattern being located on at least one second projection pattern.

[0104] For the layout unit, equivalent to the thermal coupling superposition test structure, high voltage higher than a threshold voltage is applied to the first heat generating device, the second heat generating device, the third heat generating device, the fourth heat generating device, the fifth heat generating device, the sixth heat generating device, the seventh heat generating device, the eighth heat generating device and the ninth heat generating device; current is applied to the current end of the detection wire; voltage of the voltage end of the detection wire is measured; according to the voltage and the current, the resistance corresponding to the tested wire is obtained, and the temperature rise of the tested wire is calculated through the change of the resistance.

[0105] In the embodiment, the thermal coupling effect of the heat generating devices at different positions on the tested wire is accurately evaluated, and the evaluation result is not limited by the size of the heat generating device and the distance between the heat generating device and the tested wire, so that the electromigration analysis of the tested wire is accurately performed, and the application range is wider.

[0106] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the scope defined by the claims.

Claims

1. A thermally coupled superimposed test structure, characterized in that, include: Several heat-generating devices are used to provide heat for electromigration testing; A first interconnect layer is located on a plurality of heating devices, the first interconnect layer has a test wire, the projection pattern of the test wire on the first interconnect layer is a first projection pattern, the pattern of the heating device on the first interconnect layer is a second projection pattern, a plurality of second projection patterns surround the first projection pattern and the first projection pattern is located on at least one second projection pattern. A second interconnect layer is located on the first interconnect layer. The second interconnect layer has detection wires. The detection wires are electrically connected to both ends of the wire under test. The detection wires are used to obtain the resistance of the wire under test when the heating device is turned on at different locations.

2. The thermally coupled superimposed test structure as described in claim 1, characterized in that, The first interconnect layer also has a plurality of first electrical connection lines and a plurality of second electrical connection lines that are electrically connected to a plurality of the heating devices. The plurality of first electrical connection lines, the plurality of second electrical connection lines and the test wire are distributed in parallel along a first direction, and the first electrical connection lines, the second electrical connection lines and the test wire extend along a second direction, wherein the first direction is perpendicular to the second direction.

3. The thermally coupled superimposed test structure as described in claim 2, characterized in that, The second interconnect layer also has a plurality of third electrical connection lines and a plurality of fourth electrical connection lines. The third electrical connection lines and the fourth electrical connection lines are distributed in parallel along the second direction and extend along the first direction. The third electrical connection lines are connected to the first electrical connection lines through a first contact hole, and the fourth electrical connection lines are connected to the second electrical connection lines through a second contact hole.

4. The thermally coupled superimposed test structure as described in claim 3, characterized in that, The heating device includes a substrate; a gate located on the substrate and a source and a drain located on both sides of the gate; a first electrical connection line is electrically connected to the gate; the first electrical connection line is connected to two third electrical connection lines through two first contact holes respectively; the second electrical connection line includes a source electrical connection line electrically connected to the source and a drain electrical connection line electrically connected to the drain.

5. The thermally coupled superimposed test structure as described in claim 4, characterized in that, The plurality of heating devices include at least a fifth heating device located below the test lead wire, and a fourth heating device and a sixth heating device located on both sides of the fifth heating device along a first direction. There is a gap between the first electrical connection line of the fifth heating device and the first electrical connection line of the fourth heating device, and there is also a gap between the first electrical connection line of the fifth heating device and the first electrical connection line of the sixth heating device.

6. The thermally coupled superimposed test structure as described in claim 5, characterized in that, The plurality of heating devices further includes at least a first heating device, a second heating device, and a third heating device distributed along the second direction on one side of the fifth heating device, wherein the gate of the first heating device, the gate of the second heating device, and the gate of the third heating device are electrically connected by a first electrical connection line.

7. The thermally coupled superimposed test structure as described in claim 6, characterized in that, The plurality of heating devices further includes at least a seventh heating device, an eighth heating device, and a ninth heating device distributed along the second direction on the other side of the fifth heating device, wherein the first electrical connection line of the eighth heating device and the first electrical connection line of the seventh heating device have the gap, and the first electrical connection line of the eighth heating device and the first electrical connection line of the ninth heating device have the gap.

8. The thermally coupled superimposed test structure as described in claim 7, characterized in that, The first electrical connection line of the sixth heating device and the first electrical connection line of the ninth heating device share the same third electrical connection line.

9. The thermally coupled superimposed test structure as described in claim 7, characterized in that, The source electrical connection line includes a first source electrical connection line, a second source electrical connection line, and a third source electrical connection line distributed parallel to the first direction. The sources of the first heating device, the second heating device, and the third heating device share the same first source electrical connection line. The sources of the fourth heating device, the fifth heating device, and the sixth heating device share the same second source electrical connection line. The sources of the seventh heating device, the eighth heating device, and the ninth heating device share the same third source electrical connection line. The first source electrical connection line is connected to the fourth electrical connection line located on the second heating device. The second source electrical connection line is connected to the fourth electrical connection line located on the fifth heating device. The third source electrical connection line is connected to the fourth electrical connection line located on the eighth heating device. The fourth electrical connection line connected to the source electrical connection line on the second heating device, the fifth heating device, and the eighth heating device is the same electrical connection line.

10. The thermally coupled superimposed test structure as described in claim 7, characterized in that, The drain connection line includes a first drain connection line, a second drain connection line, and a third drain connection line distributed parallel to the first direction. The drains of the first heating device, the second heating device, and the third heating device share the same first drain connection line. The drains of the fourth heating device, the fifth heating device, and the sixth heating device share the same second drain connection line. The drains of the seventh heating device, the eighth heating device, and the ninth heating device share the same third drain connection line. The first drain connection line is connected to the fourth connection line located on the second heating device. The second drain connection line is connected to the fourth connection line located on the fifth heating device. The third drain connection line is connected to the fourth connection line located on the eighth heating device. The fourth connection line connected to the drain connection line on the second heating device, the fifth heating device, and the eighth heating device is the same connection line.

11. A test method for a thermally coupled superimposed test structure, characterized in that, include: A thermally coupled superimposed test structure as described in any one of claims 1 to 10 is provided, the thermally coupled superimposed test structure comprising: a plurality of heating devices for providing heat for electromigration testing; a first interconnect layer located on the plurality of heating devices, the first interconnect layer having a test wire, the projection pattern of the test wire on the first interconnect layer being a first projection pattern, the pattern of the heating device on the first interconnect layer being a second projection pattern, the plurality of second projection patterns surrounding the first projection pattern and the first projection pattern being located on at least one second projection pattern; A second interconnect layer is located on the first interconnect layer, and the second interconnect layer has a detection wire, which is electrically connected to both ends of the wire under test; Turn on the heating devices at different locations; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

12. The test method for the thermally coupled superimposed test structure as described in claim 11, characterized in that, The first interconnect layer further includes a plurality of first electrical connection lines and a plurality of second electrical connection lines electrically connected to a plurality of the heating devices. The plurality of first electrical connection lines, the plurality of second electrical connection lines, and the test lead are distributed parallel to a first direction, and the first electrical connection lines, the second electrical connection lines, and the test lead extend along a second direction, the first direction being perpendicular to the second direction. The second interconnect layer further includes a plurality of third electrical connection lines and a plurality of fourth electrical connection lines. The third electrical connection lines and the fourth electrical connection lines are distributed parallel to the second direction, and the third electrical connection lines and the fourth electrical connection lines extend along the first direction. The third electrical connection lines are connected to the first electrical connection lines through a first contact hole, and the fourth electrical connection lines are connected to the second electrical connection lines through a second contact hole.

13. The test method for the thermally coupled superimposed test structure as described in claim 12, characterized in that, The plurality of heating devices include at least a fifth heating device located at the bottom of the test lead wire, a fourth and a sixth heating device located on both sides of the fifth heating device along a first direction, a first, a second, and a third heating device distributed along a second direction on one side of the fifth heating device, and a seventh, an eighth, and a ninth heating device distributed along the second direction on the other side of the fifth heating device. The gates of the first, second, and third heating devices are electrically connected via a first electrical connection line; and the first electrical connection line of the sixth heating device and... The third electrical connection line is shared with the first electrical connection line of the ninth heating device; the second electrical connection line includes a source electrical connection line and a drain electrical connection line, the source electrical connection line includes a first source electrical connection line, a second source electrical connection line, and a third source electrical connection line distributed parallel to the first direction, the source of the first heating device, the source of the second heating device, and the source of the third heating device share the same first source electrical connection line, the source of the fourth heating device, the source of the fifth heating device, and the source of the sixth heating device share the same second source electrical connection line, the source of the seventh heating device, and the source of the eighth heating device. The source terminals of the devices and the source terminal of the ninth heating device share the same third source terminal electrical connection line. The first source terminal electrical connection line is connected to the fourth electrical connection line located on the second heating device, the second source terminal electrical connection line is connected to the fourth electrical connection line located on the fifth heating device, and the third source terminal electrical connection line is connected to the fourth electrical connection line located on the eighth heating device. The drain terminal electrical connection line includes a first drain terminal electrical connection line, a second drain terminal electrical connection line, and a third drain terminal electrical connection line distributed parallel to the first direction. The drain terminals of the first heating device, the second heating device, and the third heating device are also connected. The drains of the fourth, fifth, and sixth heating devices share the same first drain connection line; the drains of the seventh, eighth, and ninth heating devices share the same second drain connection line; the drains of the seventh, eighth, and ninth heating devices share the same third drain connection line; the first drain connection line is connected to the fourth connection line located on the second heating device; the second drain connection line is connected to the fourth connection line located on the fifth heating device; and the third drain connection line is connected to the fourth connection line located on the eighth heating device.

14. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, When the heating device is located at the bottom of the wire under test, the method for obtaining the resistance of the wire under test includes: A high voltage higher than the threshold voltage is applied to the fifth heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

15. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test wire has opposing first sidewalls in the first direction, wherein when the heating device is located at either of the first sidewalls, the method for obtaining the resistance of the test wire includes: A high voltage higher than the threshold voltage is applied to the fourth heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

16. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test wire has opposing second sidewalls in the second direction, wherein when the heating device is located at either of the second sidewalls, the method for obtaining the resistance corresponding to the test wire includes: A high voltage higher than the threshold voltage is applied to the eighth heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

17. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test wire has opposing first sidewalls in the first direction and opposing second sidewalls in the second direction, and the corners formed at the connection between the first sidewalls and the second sidewalls, wherein when the heating device is located at any of the corners, the method for obtaining the resistance corresponding to the test wire includes: A high voltage higher than the threshold voltage is applied to the seventh heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

18. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test wire has opposing first sidewalls in the first direction and opposing second sidewalls in the second direction, and the corners formed at the connection between the first and second sidewalls, wherein when a heating device is present at one of the first sidewalls and at any of the corners connected to the first sidewalls in the first direction, the method for obtaining the resistance corresponding to the test wire includes: A high voltage higher than the threshold voltage is applied to the sixth heating device and the ninth heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

19. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test wire has opposing first sidewalls in the first direction and opposing second sidewalls in the second direction, and the corners formed at the connection between the first and second sidewalls, wherein when a heating device is present at one of the second sidewalls and at the corners connected to the second sidewalls along the second direction, the method for obtaining the resistance of the test wire includes: A high voltage higher than a threshold voltage is applied to the first heating device, the second heating device, and the third heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

20. The test method for the thermally coupled superimposed test structure as described in claim 13, characterized in that, The test conductor has opposing first sidewalls in the first direction and opposing second sidewalls in the second direction, and a corner is formed at the connection between the first sidewall and the second sidewall. When the bottom of the test conductor, the first sidewall, the second sidewall, and any of the corners all have the heating element, the method for obtaining the resistance corresponding to the test conductor includes: A high voltage higher than a threshold voltage is applied to the first heating device, the second heating device, the third heating device, the fourth heating device, the fifth heating device, the sixth heating device, the seventh heating device, the eighth heating device, and the ninth heating device; Apply current to the current end of the detection wire; By measuring the voltage at the voltage terminal of the detection wire; Based on the voltage and current, the resistance corresponding to the tested wire is obtained.

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