Magnetic tunnel junction interconnect via fill plug contact resistance measurement structure and method

Abstract

The application provides a magnetic tunnel junction interconnection via filling plug contact resistance measurement structure and a measurement method, which comprises a magnetic tunnel junction, a composite metal layer and an electrode group, the magnetic tunnel junction is a film stack comprising a magnetic metal material; the composite metal layer is connected with the magnetic tunnel junction through a via filling plug; the electrode group comprises a first electrode, a second electrode, a third electrode and a fourth electrode, the first electrode is connected with the fourth electrode through an interconnection lead wire arranged on the composite metal layer and the via filling plug; the second electrode and the third electrode are connected with the magnetic tunnel junction through a via filling plug array respectively. After a power supply is input to the electrodes, the current will mainly pass through the via filling plug and the magnetic metal material of the magnetic tunnel junction, the resistance of the magnetic metal material of the magnetic tunnel junction is extremely small and can be ignored, and therefore the measured resistance value is the contact resistance of the interconnection via, and the measured contact resistance has no error caused by the interconnection lead wire resistance.

Description

Technical Field

[0001] This invention relates to the field of spintronic device technology for MRAM memory, and in particular to a contact resistance measurement structure and method for magnetic tunnel junction interconnect via filler plugs. Background Technology

[0002] Magnetoresistive random access memory (MRAM) boasts advantages such as low power consumption, high speed, and radiation protection, making it a highly competitive emerging storage technology. Many international wafer foundries are actively engaged in the production and R&D of embedded MRAM, and some domestic companies are also actively conducting related research. The basic storage unit of MRAM is a magnetic tunnel junction (MTJ). The core unit of a MTJ typically comprises a three-layer structure: a free layer, a reference layer, and a tunneling layer. These layers are extremely thin, typically on the order of angstroms. The free layer and reference layer are generally composed of magnetic metallic materials, while the tunneling layer is typically composed of oxides. MRAM stores information using the magnetic moments of the free layer and reference layer. When the magnetic moments of the free layer and reference layer are square, the tunneling resistance of the MTJ is low; when the magnetic moments of the free layer and reference layer are antiparallel, the tunneling resistance of the MTJ is high. The MRAM read circuit determines the data state ("0" or "1") by reading the magnitude of the tunneling resistance. The magnetic square of the free layer can be changed by an applied current, so the data state of the memory cell can be rewritten to "0" or "1" by writing current.

[0003] The magnetoresistance (MR) of a magnetic tunnel junction is generally defined as the ratio of the difference in tunneling resistance between the free layer and the reference layer when they are antiparallel and parallel to the tunneling resistance when they are parallel. A larger magnetoresistance value simplifies the MRAM read circuit design. In MRAM fabrication, the top and bottom ends of the magnetic tunnel junction are typically interconnected via via fillers. Therefore, when performing magnetoresistance readings of the magnetic tunnel junction, contact resistance is inevitably introduced at the via fillers at the top and bottom ends. A large contact resistance will cause the read magnetoresistance value to be lower than the actual resistance of the magnetic tunnel junction. Furthermore, when the contact resistance values ​​of each memory cell differ significantly, the read magnetoresistance value of the tunnel junction will vary for each corresponding cell, further increasing the complexity of the MRAM read circuit design. Therefore, measuring the contact resistance at the interconnection points of the top and bottom via fillers of the magnetic tunnel junction is crucial.

[0004] There are many methods for measuring the contact resistance of metal semiconductors, the most common being those based on transmission line models, including rectangular transmission line models, dotted transmission line models, and ring transmission line models. In semiconductor device fabrication processes, many devices incorporate contact resistance monitoring units, which are typically performed during the process itself, such as testing a metal layer and its interconnect via filler using pre-defined test units. However, this type of testing method and unit cannot be used for MRAM fabrication. The reason, as mentioned earlier, is that the core structure of the magnetic tunnel junction in MRAM memory cells contains magnetic metal materials and oxide tunneling layers with thicknesses on the order of angstroms. These layers are highly reactive with gases such as water, oxygen, and carbon dioxide. Therefore, during fabrication, the magnetic tunnel junction is usually deposited in situ in a vacuum environment on a testing machine after patterning, typically with nitrides, to protect its performance from external environmental influences. Due to this unique process, the top and bottom ends of the magnetic tunnel junction cannot be transferred to a testing machine for conventional contact resistance measurements after patterning. On the other hand, even if the conventional contact resistance measurement unit is designed as a structure to be tested after the device is fabricated, a special design must be used to achieve the measurement purpose because the magnetoresistance of the magnetic tunnel junction is much larger than the resistance of the metal used in conventional semiconductor processes.

[0005] While a series structure for measuring the contact resistance of magnetic tunnel junctions can achieve contact resistance measurement at the interconnect via filler, it presents several challenges in process monitoring. Firstly, when using only an N-cell series structure to measure contact resistance, significant differences in contact resistance across interconnect processes can lead to errors in the measured values. In such cases, it is necessary to measure the contact resistance of individual magnetic tunnel junction interconnects. Secondly, the total resistance of the series structure includes the resistance of the interconnect leads, and the resistance of the interconnect leads needs to be as small as possible compared to the contact resistance value to minimize their impact. Therefore, the series structure requires a relatively large area. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a magnetic tunnel junction interconnect via-filled plug contact resistance measurement structure, comprising a magnetic tunnel junction, a composite metal layer, and an electrode assembly, wherein...

[0007] The magnetic tunnel junction is a film stack containing magnetic metallic material;

[0008] The composite metal layer is connected to the magnetic tunnel junction through a through-hole filler plug;

[0009] The electrode group includes a first electrode, a second electrode, a third electrode, and a fourth electrode. The first electrode is connected to the fourth electrode via interconnect leads disposed on the composite metal layer and through via-hole fillers. The second electrode and the third electrode are respectively connected to the magnetic tunnel junction via via-hole filler arrays.

[0010] Optionally, when measuring the contact resistance of the through-hole filling plug, a probe is used to simultaneously contact the first electrode, the second electrode, the third electrode, and the fourth electrode, respectively.

[0011] Current is input to the first and third electrodes via a probe, and the voltage of the second and fourth electrodes is measured via the probe; or

[0012] Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe.

[0013] The contact resistance is then calculated using the following formula:

[0014]

[0015] In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

[0016] Optionally, the composite metal layer and the through-hole filler are both disposed at the top of the magnetic tunnel junction, and the first electrode, second electrode, third electrode, and fourth electrode are disposed on the composite metal layer, or...

[0017] The composite metal layer and the via filler are both disposed at the bottom end of the magnetic tunnel junction. The first electrode, the second electrode, the third electrode and the fourth electrode are disposed on the side of the magnetic tunnel junction away from the composite metal layer. The first electrode and the fourth electrode are respectively connected to the interconnect leads disposed on the composite metal layer through the magnetic tunnel junction via the via filler array.

[0018] Optionally, the through-hole filling plug array is an array formed by arranging i×j through-hole filling plugs.

[0019] Optionally, the first electrode, the second electrode, the third electrode, and the fourth electrode are arranged in a centrally symmetrical manner around the position of the through-hole filling plug.

[0020] Optionally, the first electrode, the second electrode, the third electrode, and the fourth electrode are each at the same distance from the through-hole filling plug.

[0021] Optionally, the first electrode, the second electrode, the third electrode, the fourth electrode, and the interconnect leads are all formed by a patterning process;

[0022] The second and third electrodes are interconnected with the top or bottom of the magnetic tunnel junction via an array of through-hole fillers.

[0023] Optionally, the composite metal layer is a conventional semiconductor process metal layer.

[0024] Optionally, the resistance value of the magnetic tunnel junction is obtained using the following algorithm:

[0025]

[0026] In the above formula, R S R represents the resistance value of a magnetic tunnel junction. A The area represents the resistivity of the magnetic tunnel junction; S represents the area of ​​the shape.

[0027] Based on the connection relationship, the formula for calculating the contact resistance is corrected by modifying the resistance value of the magnetic tunnel junction, thereby obtaining the accurate contact resistance.

[0028] Optionally, the interconnecting leads may be configured with a 0-degree, 45-degree, or 90-degree orientation.

[0029] The present invention also provides a method for measuring the contact resistance of a magnetic tunnel junction interconnect via filler plug, which uses the above-mentioned magnetic tunnel junction interconnect via filler plug contact resistance measurement structure, and uses a probe to simultaneously contact the first electrode, the second electrode, the third electrode and the fourth electrode respectively.

[0030] Current is input to the first and third electrodes via a probe, and the voltage of the second and fourth electrodes is measured via the probe; or

[0031] Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe.

[0032] The contact resistance is then calculated using the following formula:

[0033]

[0034] In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

[0035] This patent provides a contact resistance measurement structure for the interconnect via-filled plug of a magnetic tunnel junction (MTJ). This structure measures the contact resistance at the via-filled plug of a single MTJ. The contact resistance of a single via-filled plug can be measured using an electrode array. During measurement, after power is supplied to the electrodes, the current primarily flows through the metal above the tunneling layer of the MTJ. The current tends to flow through the magnetic layer above the tunneling layer. The main sources of voltage drop are the stacked magnetic metal materials above the tunneling layer and the contact resistance of the interconnect via-filled plug. The stacked magnetic metal materials are mainly metal, and their resistance is small and negligible. Therefore, the resistance measured by the electrodes can be equivalent to the interconnect resistance of the via-filled plug at the top of the MTJ. This structure can accurately measure the contact resistance at the via-filled plug of the MTJ without introducing errors caused by the resistance of the interconnect leads. This is crucial for optimizing and monitoring the contact resistance at the via-filled plug interconnect during the MTJ fabrication process.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0037] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0038] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0039] Figure 1 This is a schematic planar view of a magnetic tunnel junction interconnect via-filled plug contact resistance measurement structure according to an embodiment of the present invention;

[0040] Figure 2 for Figure 1 A schematic cross-sectional view of the through-hole filling plug location in the embodiment;

[0041] Figure 3 This is a schematic plan view of a second embodiment of the magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure of the present invention;

[0042] Figure 4 for Figure 3 A schematic cross-sectional view of the through-hole filling plug location in the embodiment;

[0043] In the figure: 1-magnetic tunnel junction, 2-composite metal layer, 3-electrode group, 31-first electrode, 32-second electrode, 33-third electrode, 34-fourth electrode, 4-through-hole filler, 5-through-hole filler array, 6-interconnect lead. Detailed Implementation

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0045] like Figure 1 and 2 As shown, this embodiment of the invention provides a magnetic tunnel junction interconnect via-filled plug contact resistance measurement structure, including a magnetic tunnel junction 1, a composite metal layer 2, and an electrode group 3, wherein...

[0046] The magnetic tunnel junction 1 is a film stack containing magnetic metal material;

[0047] The composite metal layer 2 is connected to the magnetic tunnel junction 1 through a through-hole filling plug 4;

[0048] The electrode group 3 includes a first electrode 31, a second electrode 32, a third electrode 33 and a fourth electrode 34. The first electrode 31 is connected to the fourth electrode 34 via an interconnect lead 6 disposed on the composite metal layer and a through-hole filler 4. The second electrode 32 and the third electrode 33 are respectively connected to the magnetic tunnel junction 1 via an array of through-hole fillers.

[0049] The working principle and beneficial effects of the above technical solution are as follows: The measurement structure of this solution is used to monitor the contact resistance of the via-hole filler in the interconnecting via of a single magnetic tunnel junction during the fabrication of the magnetic tunnel junction. The magnetic tunnel junction and the composite metal layer are insulated by a dielectric layer. In order to achieve functional connection between the magnetic tunnel junction and the composite metal layer, interconnecting vias need to be set on the dielectric layer, and then via-hole filler is filled in the interconnecting vias to achieve electrical connection between the magnetic tunnel junction and the composite metal layer. For example, tungsten can be used to fill the vias to form via-hole filler. The magnetic tunnel junction can be divided into a capping layer, a free layer, a tunneling layer, a reference layer, a pinning layer, and a seed layer according to its function. The tunneling layer is a non-metallic material, and the other layers are magnetic metallic materials. During measurement, after power is input to the electrodes, the current flows through the first electrode and the interconnecting lead to the fourth electrode, which is grounded; another path goes through the via-hole filler array of the third electrode to the magnetic tunnel junction, and from the magnetic tunnel junction to the via-hole filler array of the second electrode, which returns to the second electrode, which is grounded; or the current is reversed. Since the tunneling layer of a magnetic tunnel junction is made of a high-resistivity oxide material, while the free layer and capping layer are made of magnetic metal materials, the current will mainly pass through the free layer and capping layer above the tunneling layer of the magnetic tunnel junction. The resistance of the capping layer and free layer is extremely small and can be ignored. Therefore, the measured resistance value is the contact resistance of the via filler in the interconnect via. The structure designed in this scheme can accurately measure the contact resistance at the via filler of the magnetic tunnel junction without introducing errors caused by the resistance of the interconnect leads. This is crucial for optimizing and monitoring the contact resistance of the via filler in the magnetic tunnel junction fabrication process. The measurement structure of this scheme is applicable to various transmission line models, including but not limited to rectangular transmission line models, dotted transmission line models, ring transmission line models, patched disk transmission line models, inner ring circular transmission line models, and multi-ring transmission line models.

[0050] In one embodiment, when measuring the contact resistance of the through-hole filling plug, a probe is simultaneously contacted with the first electrode, the second electrode, the third electrode, and the fourth electrode, respectively.

[0051] Current is input to the first and third electrodes via a probe, and the voltage of the second and fourth electrodes is measured via the probe; or

[0052] Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe.

[0053] The contact resistance is then calculated using the following formula:

[0054]

[0055] In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

[0056] The working principle and beneficial effects of the above technical solution are as follows: When performing measurements, since the tunneling layer of the magnetic tunnel junction is made of oxide material with high resistance, and the free layer and capping layer are made of metal material, the current will mainly pass through the free layer and capping layer above the tunneling layer of the magnetic tunnel junction. Since the resistance of the capping layer and the free layer is extremely small and negligible, the voltage drop during measurement mainly comes from the contact resistance of the interconnect via filler. Therefore, the contact resistance of the via filler can be calculated using the above formula based on the measurement data.

[0057] In one embodiment, such as Figure 1-4 As shown, the composite metal layer 2 and the through-hole filler 4 are both disposed at the top of the magnetic tunnel junction 1. The first electrode 31, the second electrode 32, the third electrode 33, and the fourth electrode 34 are disposed on the composite metal layer 2, or...

[0058] The composite metal layer 2 and the via filler 4 are both disposed at the bottom end of the magnetic tunnel junction 1. The first electrode 31, the second electrode 32, the third electrode 33 and the fourth electrode 34 are disposed on the side of the magnetic tunnel junction 1 away from the composite metal layer 2. The first electrode 31 and the fourth electrode 34 are respectively connected to the interconnecting leads disposed on the composite metal layer 2 through the magnetic tunnel junction 1 via the via filler array 5.

[0059] The working principle and beneficial effects of the above technical solution are as follows: Wherein, Figure 1 and 2 In the illustrated embodiment, both the composite metal layer and the through-hole filler are disposed at the top of the magnetic tunnel junction; Figure 3 and 4 In the illustrated embodiment, both the composite metal layer and the via filler are disposed at the bottom of the magnetic tunnel junction. Regardless of the stacking relationship between the composite metal layer and the via filler and the magnetic tunnel junction, this solution ensures that the second and third electrodes of the electrode group are in contact with the magnetic tunnel junction through the via filler array, thereby realizing the measurement of the contact resistance of the interconnect via of a single magnetic tunnel junction, avoiding errors caused by the resistance of the interconnect leads, and ensuring the accuracy of the contact resistance measurement.

[0060] In one embodiment, such as Figure 1-4 As shown, the through-hole filling plug array 5 is an array formed by arranging i×j through-hole filling plugs; the composite metal layer is a conventional semiconductor process metal layer, such as titanium, aluminum or copper.

[0061] The working principle and beneficial effects of the above technical solution are as follows: The through-hole filling plug array used in this solution is an array formed by arranging i×j through-hole filling plugs. The composite metal layer is a conventional semiconductor process metal layer, which can be made of metals such as titanium, aluminum or copper. By adding the structure described in this solution during the preparation of the magnetic tunnel junction, the contact resistance of the through-hole at the top of the magnetic tunnel junction can be monitored. This structure is easy to implement in conventional semiconductor processes and has high manufacturing efficiency and low cost.

[0062] In one embodiment, such as Figure 1 and Figure 3 As shown, the first electrode 31, the second electrode 32, the third electrode 33 and the fourth electrode 34 are arranged symmetrically at intervals around the position of the through hole filling plug 4.

[0063] The working principle and beneficial effects of the above technical solution are as follows: The symmetrical spacing of the electrodes in this solution can be longitudinal or transverse symmetrical, or centrally symmetrical; the first and second electrodes can be symmetrical, and the third and fourth electrodes can be symmetrical; the first and third electrodes can be symmetrical, and the second and fourth electrodes can be symmetrical; the first and fourth electrodes can be symmetrical, and the second and third electrodes can be symmetrical; the positions of the first, second, third, and fourth electrodes are connected sequentially to form a rectangle or square; the connection between the first and fourth electrodes and the connection between the second and third electrodes make the electrode group arrangement flexible and can be adapted and adjusted according to actual needs, thereby facilitating the setting of other components and saving costs.

[0064] In one embodiment, the first electrode 31, the second electrode 32, the third electrode 33, and the fourth electrode 34 are each at the same distance from the through-hole filling plug 4.

[0065] The working principle and beneficial effects of the above technical solution are as follows: The distance between each electrode and the through hole filling plug in this solution is set to the same distance. This distance can be selected to be the distance value with the most compact design layout, thus reducing the area, or more functional structures can be laid out in the same area, which can save costs.

[0066] In one embodiment, the first electrode 31, the second electrode 32, the third electrode 33, the fourth electrode 34, and the interconnect leads are all formed by a patterning process;

[0067] The second electrode 32 and the third electrode 33 are interconnected with the top or bottom of the magnetic tunnel junction 1 through the through-hole filling plug array 5;

[0068] The interconnecting leads are configured with a 0-degree, 45-degree (135-degree), or 90-degree orientation.

[0069] The working principle and beneficial effects of the above technical solution are as follows: This solution uses a patterned process to form both the electrodes and interconnections, taking into account both functionality and structural compactness; the interconnection leads of this solution are set with a 0-degree, 45-degree (135-degree) or 90-degree orientation, which can be flexibly set according to the probe spacing of the measuring machine, facilitating measurement and saving costs.

[0070] In one embodiment, the resistance value of the magnetic tunnel junction is obtained using the following algorithm:

[0071]

[0072] In the above formula, R S R represents the resistance value of a magnetic tunnel junction. A The area represents the resistivity of the magnetic tunnel junction; S represents the area of ​​the shape.

[0073] Based on the connection relationship, the formula for calculating the contact resistance is corrected by modifying the resistance value of the magnetic tunnel junction, thereby obtaining the accurate contact resistance.

[0074] The working principle and beneficial effects of the above technical solution are as follows: When measuring the contact resistance of the bottom interconnect via of the magnetic tunnel junction, since the magnetic tunnel junction is a film stack composed of multiple layers of magnetic and non-magnetic layers, the resistance of the magnetic tunnel junction is the ratio of the resistance area of ​​the magnetic tunnel junction to the area of ​​the pattern. This can be achieved by designing the area of ​​the magnetic tunnel junction to be much larger than the via filler, thus reducing the resistance of the magnetic tunnel junction. However, if the resistance of the magnetic tunnel junction cannot be ignored in the calculation of the contact resistance of the via filler, then the resistance of the magnetic tunnel junction can be included in the consideration, and the calculation formula for the contact resistance can be modified. Therefore, the contact resistance of the via filler calculated based on the measurement data is more accurate, further improving the measurement accuracy of the contact resistance of the via filler. Among these, the magnetic tunnel junction resistance area R... A The area S of a graphic is related to the material and design layout.

[0075] This invention also provides a method for measuring the contact resistance of a magnetic tunnel junction interconnect via filler plug, using the above-mentioned magnetic tunnel junction interconnect via filler plug contact resistance measurement structure, and simultaneously contacting the first electrode, the second electrode, the third electrode and the fourth electrode with a probe.

[0076] Current is input to the first and third electrodes via a probe, and the voltage of the second and fourth electrodes is measured via the probe; or

[0077] Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe.

[0078] The contact resistance is then calculated using the following formula:

[0079]

[0080] In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

[0081] The working principle and beneficial effects of the above technical solution are as follows: When the interconnect via is located at the top of the magnetic tunnel junction, since the tunneling layer of the magnetic tunnel junction is usually made of oxide material, while the capping layer and free layer are made of magnetic metal material, after the power is input to the electrode, the current flows through the first electrode and the interconnect lead to the fourth electrode, which is grounded; another path goes through the via-filled plug array of the third electrode to the magnetic tunnel junction, and from the magnetic tunnel junction to the via-filled plug array of the second electrode back to the second electrode, which is grounded; or the current is reversed. Since the tunneling layer of the magnetic tunnel junction is made of a high-resistivity oxide material, while the free layer and capping layer are made of magnetic metal materials, the current will mainly pass through the free layer and capping layer above the tunneling layer of the magnetic tunnel junction. The resistance of the capping layer and free layer is extremely small and can be ignored. When the interconnect via is located at the bottom of the magnetic tunnel junction, since the resistance of the magnetic tunnel junction is the ratio of the resistance area of ​​the magnetic tunnel junction to the area of ​​the pattern, the area of ​​the magnetic tunnel junction designed in this scheme is much larger than the via filler, so the resistance of the magnetic tunnel junction is small and can be ignored. If it cannot be ignored, it can be compensated by calculating the resistance value of the magnetic tunnel junction. Therefore, the accurate contact resistance of a single via filler can be obtained by calculating the above formula based on the measurement data.

[0082] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A magnetic tunnel junction interconnect via-filled plug contact resistance measurement structure, characterized in that, It includes a magnetic tunnel junction, a composite metal layer, and an electrode assembly, among which The magnetic tunnel junction is a film stack containing magnetic metallic material; The composite metal layer is connected to the magnetic tunnel junction through a through-hole filler plug; The electrode group includes a first electrode, a second electrode, a third electrode, and a fourth electrode. The first electrode is connected to the fourth electrode via interconnect leads disposed on the composite metal layer and through via-hole fillers. The second electrode and the third electrode are respectively connected to the magnetic tunnel junction via via-hole filler arrays.

2. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, When measuring the contact resistance of the through-hole filling plug, a probe is used to simultaneously contact the first electrode, the second electrode, the third electrode, and the fourth electrode, respectively. Current is input to the first and third electrodes using a probe, and the voltage of the second and fourth electrodes is measured using a probe. or Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe. The contact resistance is then calculated using the following formula: In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

3. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The composite metal layer and the through-hole filler are both disposed at the top of the magnetic tunnel junction, and the first, second, third, and fourth electrodes are disposed on the composite metal layer, or... The composite metal layer and the via filler are both disposed at the bottom end of the magnetic tunnel junction. The first electrode, the second electrode, the third electrode and the fourth electrode are disposed on the side of the magnetic tunnel junction away from the composite metal layer. The first electrode and the fourth electrode are respectively connected to the interconnect leads disposed on the composite metal layer through the magnetic tunnel junction via the via filler array.

4. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The through-hole filling plug array is an array formed by arranging i×j through-hole filling plugs.

5. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The first electrode, the second electrode, the third electrode, and the fourth electrode are arranged in a centrally symmetrical manner around the position of the through hole filling plug.

6. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The first electrode, the second electrode, the third electrode, and the fourth electrode are each at the same distance from the through-hole filling plug.

7. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The first electrode, second electrode, third electrode, fourth electrode, and interconnect leads are all formed by patterning processes; The second and third electrodes are interconnected with the top or bottom of the magnetic tunnel junction via an array of through-hole fillers.

8. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 1, characterized in that, The composite metal layer is a conventional semiconductor process metal layer.

9. The magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure according to claim 2, characterized in that, The resistance value of the magnetic tunnel junction is obtained using the following algorithm: In the above formula, R S R represents the resistance value of a magnetic tunnel junction. A The area represents the resistivity of the magnetic tunnel junction; S represents the area of ​​the shape. Based on the connection relationship, the formula for calculating the contact resistance is corrected by modifying the resistance value of the magnetic tunnel junction, thereby obtaining the accurate contact resistance.

10. A method for measuring the contact resistance of a magnetic tunnel junction interconnect via filled with a plug, characterized in that, Using the magnetic tunnel junction interconnection via-hole filling plug contact resistance measurement structure as described in claim 1, a probe simultaneously contacts the first electrode, the second electrode, the third electrode, and the fourth electrode respectively; Current is input to the first and third electrodes using a probe, and the voltage of the second and fourth electrodes is measured using a probe. or Current is input to the second and fourth electrodes through a probe, and the voltage of the first and third electrodes is measured through a probe. The contact resistance is then calculated using the following formula: In the above formula, Rc represents the contact resistance of the through-hole filler; U represents the measured voltage; and I represents the input current during measurement.

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