Magnetic memory device and manufacturing method thereof

Abstract

The invention provides a magnetic memory device and a manufacturing method thereof. The magnetic memory device comprises a magnetic tunnel junction which is formed by etching by taking a mask layer as a mask; the mask layer comprises a first split body, a second split body arranged on one side, far away from the magnetic tunnel junction, of the first split body, and a third split body surrounding the second split body; the first split body and the second split body are conductive, and the third split body is insulated; wherein the outer peripheral surface of the third split body is aligned with the outer peripheral surface of the first split body, or the outer peripheral surface of the third split body is sunken in the outer peripheral surface of the first split body. The magnetic memory device is used for reducing the short circuit of the magnetic tunnel junction and preventing the key size of the magnetic tunnel junction from increasing.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a magnetic storage device and a manufacturing method thereof. Background Art

[0002] The rapid development of the Internet of Things and artificial intelligence (AI) is driving increasing demands for data storage. Magnetic Random Access Memory (MRAM), with its non-volatility, fast read / write speeds, and long lifespan, is widely used in aerospace, automotive, consumer electronics, large computers, and other fields.

[0003] MRAM can be categorized into STT-MRAM (Spin Transfer Torque-MRAM) and SOT-MRAM (Spin Orbit Torque-MRAM) based on their read / write methods. The core components of SOT-MRAM are the magnetic tunnel junction (MTJ) and the spin-orbit torque (SOT) layer. The MTJ has a sandwich structure, with an oxide layer sandwiched between two ferromagnetic layers. The oxide layer serves as the tunneling layer, while the two ferromagnetic layers are the free layer and the pinned layer, which are in contact with the SOT layer. The magnetic moment of the pinned layer is fixed, while the direction of the free layer's magnetic moment can be flipped by the flow of current through the SOT layer. When the magnetic moments of the free and pinned layers are aligned, they exhibit low resistance. When the magnetic moments of the free and pinned layers are aligned, they exhibit high resistance. The difference in resistance represents "0" and "1," thereby storing information.

[0004] There are many challenges in the above-mentioned MRAM preparation process, and one of them is the re-sputtering during the etching process that causes the MTJ to short-circuit and fail. Since the MTJ uses a physical etching process during the etching process, there will be metal re-sputtering in this process. If the metal of the mask layer and the metal of the ferromagnetic layer are sputtered to the sidewalls of the oxide layer, it will connect the fixed layer and the free layer, causing a short circuit problem and causing the MTJ to fail. To solve the above problem, one method is to form a protective layer on the sidewalls of the mask layer after etching the mask layer and before etching the MTJ, and then etch to form the MTJ. In this way, the metal of the mask layer is prevented from being etched and will no longer be sputtered to the sidewalls of the oxide layer.

[0005] However, the above method also has defects. The presence of the protective layer enlarges the mask size and transmits this size in the subsequent MTJ etching, making the critical dimension (CD) of the MTJ formed by etching larger. It can be seen that the MTJ finally formed by the above method is difficult to reach the expected size. At the same time, the larger MTJ size will occupy additional layout area, which is not conducive to improving density. Summary of the Invention

[0006] Embodiments of the present application provide a magnetic memory device and a method for manufacturing the same, so as to reduce magnetic tunnel junction short circuits and prevent the critical dimension of the magnetic tunnel junction from becoming larger.

[0007] In a first aspect, an embodiment of the present application provides a magnetic memory device, comprising: a magnetic tunnel junction, the magnetic tunnel junction being formed by etching using a mask layer as a mask;

[0008] The mask layer includes: a first split body, a second split body arranged on a side of the first split body away from the magnetic tunnel junction, and a third split body surrounding the second split body;

[0009] The first and second parts are conductive, and the third part is insulated;

[0010] The outer peripheral surface of the third split body is aligned with the outer peripheral surface of the first split body, or the outer peripheral surface of the third split body is recessed into the outer peripheral surface of the first split body.

[0011] In some possible embodiments, along the height direction of the mask layer, the size of the first split body is smaller than the size of the third split body, and smaller than the size of the second split body.

[0012] In some possible embodiments, a surface of the second split body facing away from the first split body is flush with a surface of the third split body facing away from the first split body.

[0013] In some possible embodiments, the etching rate of the third split body is greater than the etching rate of the first split body, and greater than the etching rate of the second split body.

[0014] In some possible embodiments, the first split body and the second split body form an integral structure;

[0015] The third sub-body completely covers the outer peripheral surface of the second sub-body.

[0016] The magnetic memory device provided in an embodiment of the present application includes a magnetic tunnel junction, which is formed by etching using a mask layer as a mask. The mask layer includes a first body, a second body, and a third body. The second body is arranged on a side of the first body away from the magnetic tunnel junction, and the third body surrounds the second body. The first body and the second body are conductive, while the third body is insulating. During the etching process to form the magnetic tunnel junction, the third body is consumed first and sputtered onto the sidewalls of the magnetic tunnel junction. The third body has insulating properties and does not conduct current between the free layer and the reference layer of the magnetic tunnel junction, thereby preventing short-circuit failure of the magnetic tunnel junction. Furthermore, when the second body is subsequently consumed, the second body sputters onto the third body located on the sidewalls of the magnetic tunnel junction, without directly contacting the sidewalls of the magnetic tunnel junction and thus without conducting current between the free layer and the reference layer of the magnetic tunnel junction. That is, the sputtered third body isolates the sputtered second body from the magnetic tunnel junction, thereby further preventing short-circuit failure of the magnetic tunnel junction. The outer peripheral surface of the third split is aligned with the outer peripheral surface of the first split, or the outer peripheral surface of the third split is recessed in the outer peripheral surface of the first split. The outer peripheral contour of the third split will not exceed the outer peripheral contour of the first split. The third split will not increase the critical dimensions of the mask layer, will not occupy additional layout area, resulting in reduced density, and the critical dimensions of the formed magnetic tunnel junction will not be magnified due to the mask layer, thereby ensuring that the magnetic tunnel junction finally formed reaches the expected size.

[0017] In a second aspect, an embodiment of the present application provides a method for manufacturing a magnetic memory device, comprising:

[0018] forming a magnetic tunnel junction stack layer;

[0019] forming a mask layer, wherein the mask layer is formed on one side of the magnetic tunnel junction stack layer;

[0020] The mask layer includes: a first split body, a second split body arranged on a side of the first split body away from the magnetic tunnel junction, and a third split body surrounding the second split body;

[0021] The first and second parts are conductive, and the third part is insulated;

[0022] The outer peripheral surface of the third split body is aligned with the outer peripheral surface of the first split body, or the outer peripheral surface of the third split body is recessed into the outer peripheral surface of the first split body;

[0023] Using the mask layer as a mask, the magnetic tunnel junction stacking layer is etched to form a magnetic tunnel junction.

[0024] In some possible embodiments, forming a mask layer includes:

[0025] patterning the initial mask layer to form mask pillars;

[0026] forming a sacrificial layer, wherein the sacrificial layer covers the top surface and a portion of the side surface of the mask pillar, and a portion of the side surface of the mask pillar away from the magnetic tunnel junction stack layer is exposed;

[0027] The exposed side of the mask column is modified to form a third split, the mask column in contact with the side of the third split forms a second split, and the mask column located on the side of the third split and the second split close to the magnetic tunnel junction stacking layer forms a first split.

[0028] In some possible embodiments, along the height direction of the mask layer, the size of the magnetic tunnel junction stack layer is smaller than the size of the third segment and smaller than the size of the second segment, so that a portion of the third segment is retained after the magnetic tunnel junction is formed.

[0029] In some possible embodiments, forming a mask layer includes:

[0030] patterning the initial mask layer to form grooves in the initial mask layer;

[0031] forming a third split body, wherein the third split body covers the side wall of the groove;

[0032] A second body is formed, and the second body fills the area enclosed by the third body;

[0033] Part of the initial mask layer is removed, and the initial mask layer on the third body and the second body close to the magnetic tunnel junction stack layer is retained to form a first body.

[0034] In some possible embodiments, when etching the magnetic tunnel junction stack layer, an angle is formed between the etching direction and the normal direction of the upper surface of the mask layer.

[0035] The method for manufacturing a magnetic memory device provided in an embodiment of the present application includes: forming a magnetic tunnel junction stack; forming a mask layer, the mask layer being formed on one side of the magnetic tunnel junction stack; etching the magnetic tunnel junction stack using the mask layer as a mask to form a magnetic tunnel junction. The mask layer includes: a first split, a second split arranged on a side of the first split away from the magnetic tunnel junction, and a third split surrounding the second split; the first split and the second split are conductive, and the third split is insulating; the outer peripheral surface of the third split is aligned with the outer peripheral surface of the first split, or the outer peripheral surface of the third split is recessed in the outer peripheral surface of the first split. During the etching process to form the magnetic tunnel junction, the insulating third split is consumed first, and the third split is sputtered onto the sidewalls of the magnetic tunnel junction. The third split is insulating and will not conduct the free layer and reference layer of the magnetic tunnel junction, thereby preventing the magnetic tunnel junction from short-circuiting. When the second body is subsequently consumed, it sputters onto the third body, without directly contacting the sidewalls of the magnetic tunnel junction and thus without conducting the free layer and reference layer of the magnetic tunnel junction. This means the sputtered third body isolates the sputtered second body from the magnetic tunnel junction, further preventing short-circuit failure of the magnetic tunnel junction. Furthermore, the outer contour of the third body does not exceed that of the first body, and the third body does not increase the critical dimensions of the mask layer, nor does it occupy additional layout area, leading to reduced density. Furthermore, the critical dimensions of the resulting magnetic tunnel junction are not magnified by the mask layer, ensuring that the resulting magnetic tunnel junction reaches the desired size. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0037] Figure 1 Schematic diagram of etching of the magnetic tunnel junction provided in this application;

[0038] Figure 2 A flowchart of the manufacturing process of the magnetic memory device provided in this application;

[0039] Figure 3 A schematic diagram of the process after forming the initial mask layer provided in this application;

[0040] Figure 4 A schematic diagram of the sacrificial layer provided in this application;

[0041] Figure 5 A schematic diagram of the third body formed in this application;

[0042] Figure 6 This is a schematic diagram after removing the sacrificial layer provided in this application;

[0043] Figure 7 A schematic diagram of a magnetic tunnel junction formed in the present application;

[0044] Figure 8 A schematic diagram of the groove formed in this application;

[0045] Figure 9 Another schematic diagram after the third body is formed provided by this application;

[0046] Figure 10 A schematic diagram of the second split body provided in this application;

[0047] Figure 11 A schematic diagram of the first split body provided in this application;

[0048] Figure 12 Another schematic diagram after forming a magnetic tunnel junction provided by this application.

[0049] Description of reference numerals:

[0050] 10-substrate;

[0051] 20-spin-orbit moment layer; 21-spin-orbit moment initial layer;

[0052] 30-magnetic tunnel junction; 31-magnetic tunnel junction stack;

[0053] 40-etching stop layer;

[0054] 50 - mask layer; 51 - first sub-body; 52 - second sub-body; 53 - third sub-body; 54 - initial mask layer; 55 - mask pillar; 56 - groove;

[0055] 60-Sacrificial layer. DETAILED DESCRIPTION

[0056] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0057] In the prior art, to prevent the mask layer metal from sputtering onto the MTJ sidewalls during MTJ etching, potentially causing device short circuits, a non-conductive protective layer is typically formed on the sidewalls after the mask layer is etched. This prevents the mask layer from being etched during the MTJ etching process, thereby preventing further sputtering of the mask layer. However, the protective layer formed on the mask layer sidewalls increases the mask size, increasing the critical dimensions of the MTJ obtained after etching, making it difficult to achieve an MTJ with the most advanced CD.

[0058] The magnetic storage device and its manufacturing method provided by the present application form a mask layer, the mask layer includes a first conductive split and a second split, and a third split of an insulating layer, the second split is arranged on the side of the first split away from the magnetic tunnel junction, and the third split surrounds the second split. In the process of etching to form a magnetic tunnel junction using the mask layer as a mask, the third split is sputtered to the side wall of the magnetic tunnel junction, and will not conduct the free layer and reference layer of the magnetic tunnel junction, thereby avoiding short-circuit failure of the magnetic tunnel junction. In addition, the outer peripheral contour of the third split will not exceed the outer peripheral contour of the first split, and the third split will not increase the critical dimension of the mask layer, so that the critical dimension of the formed magnetic tunnel junction will not be enlarged due to the mask layer, and will not occupy additional layout area, thereby improving storage density. By setting a mask layer with a composite structure, the sputtering problem of conductive materials can be solved, and the enlargement of the critical dimension of the MTJ after etching can be avoided.

[0059] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0060] The present invention provides a magnetic memory device, which is, for example, a spin transfer torque magnetoresistive memory or a spin orbit torque magnetoresistive memory. Figure 1 The magnetic memory device includes a magnetic tunnel junction 30, which is formed by etching using a mask layer 50 as a mask. The mask layer 50 includes a first body 51, a second body 52 disposed on a side of the first body 51 away from the magnetic tunnel junction 30, and a third body 53 surrounding the second body 52. ​​The first body 51 and the second body 52 are conductive, while the third body 53 is insulating. The outer periphery of the third body 53 is aligned with the outer periphery of the first body 51, or is recessed into the outer periphery of the first body 51.

[0061] The magnetic tunnel junction 30 is the core structure of the magnetic memory device, used to store data. The shape of the magnetic tunnel junction 30 can be cylindrical, elliptical, rectangular, or toroidal. It comprises a free layer, a barrier layer, and a reference layer stacked in sequence. When the free and reference layers have the same magnetization orientation (i.e., parallel), the magnetic tunnel junction 30 is in a low-resistance state, corresponding to the storage of data "1." When the free and reference layers have opposite magnetization orientations (i.e., antiparallel), the magnetic tunnel junction 30 is in a high-resistance state, corresponding to the storage of data "0."

[0062] The magnetization direction of the free layer can be changed, while the magnetization direction of the reference layer is fixed. Both the free layer and the reference layer are made of ferromagnetic materials, such as at least one of Co, Fe, B, Ni, Ru, Ir, and Pt. The materials of the free layer and the reference layer can be the same or different, and this is not limited in the present embodiment. The barrier layer isolates the free layer and the reference layer, and the barrier layer is made of an insulating material, such as at least one of MgO, Al2O3, and SiO2.

[0063] The magnetic tunnel junction 30 may further include other film layers as needed, such as a pinning layer, which is used to pin the magnetization direction of the reference layer in a fixed direction (e.g., in-plane or perpendicular direction). The pinning layer may be a single layer or a stacked layer. For example, the pinning layer includes a ferromagnetic layer and an antiferromagnetic layer, which are alternately stacked. The ferromagnetic layer may be made of a ferromagnetic material, such as at least one of Co, Fe, B, Ni, Ru, I, and Pt. The antiferromagnetic layer may be made of a collinear antiferromagnetic material and a non-collinear antiferromagnetic material, such as at least one of IrMn, PtMn, FeMn, NiMn, and MnSn.

[0064] The formation of the magnetic tunnel junction 30 by etching with the mask layer 50 as a mask means that the material is selectively removed through a predefined mask pattern using a photolithography and etching process, thereby forming the desired magnetic tunnel junction 30. In some possible examples, see Figures 3 to 12 The magnetic tunnel junction 30 can be formed by the following process: forming a predefined mask layer 50 mask pattern on the magnetic tunnel junction stack layer 31 through a photolithography process to form the mask layer 50; etching the magnetic tunnel junction stack layer 31 by a physical or chemical etching method to remove the area not covered by the mask layer 50 and retain the area covered by the mask layer 50 to form the magnetic tunnel junction 30; after the etching is completed, the remaining mask layer 50 can be used as an electrical connection between the magnetic tunnel junction 30 and the external circuit.

[0065] In some possible examples, when the mask layer 50 is etched to form the magnetic tunnel junction 30, an angle is formed between the etching direction and the normal direction of the upper surface of the mask layer 50. The etching direction refers to the spatial orientation of material removal during the etching process, such as the bombardment direction of ions. The angle is, for example, 15° to 45° between the etching direction and the normal direction of the upper surface of the mask layer 50. Figure 1 As shown, the normal direction of the upper surface of the mask layer 50 is, for example, the height direction of the mask layer 50, i.e., the vertical direction (Z direction). The etching direction is the E direction, which is oblique, i.e., tilted relative to the vertical direction. This can also remove residues on the sidewalls of the magnetic tunnel junction 30, thereby improving the performance and yield of the magnetic tunnel junction 30.

[0066] Continue reading Figure 1The mask layer 50 includes a first body 51, a second body 52, and a third body 53. The second body 52 is located on the side of the first body 51 away from the magnetic tunnel junction 30, and the third body 53 surrounds the second body 52. ​​The third body 53 and the second body 52 are arranged on the same side, that is, the third body 53 is also located on the side of the first body 51 away from the magnetic tunnel junction 30. Figure 1 As shown, the second body 52 and the third body 53 are both located above the first body 51, and along the X direction shown in FIG1 , the second body 52 is located inside the third body 53. The first body 51 forms the lower portion of the mask layer 50, and the second body 52 and the third body 53 form the upper portion of the mask layer 50.

[0067] The first body 51 and the second body 52 can be cylindrical, such as a circular cylinder, an elliptical cylinder or a rectangular cylinder, and the shapes of the first body 51 and the second body 52 can be the same or different. The third body 53 surrounds the second body 52, and its shape can be a ring, such as a circular ring, an elliptical ring or a rectangular ring. The specific shapes of the first body 51, the second body 52 and the third body 53 can be selected according to the shape requirements of the magnetic tunnel junction 30. Exemplarily, the first body 51 and the second body 52 are both elliptical cylinders, and the third body 53 is an elliptical ring; another exemplary embodiment, the first body 51 is an elliptical cylinder, the second body 52 is a circular cylinder, and the third body 53 is an annular cylinder with an outer elliptical and an inner circular shape.

[0068] Continue reading Figure 1 , the first split 51 and the second split 52 are conductive, the third split 53 is insulating, and the mask layer 50 forms a composite mask structure. Exemplarily, the material of the first split 51 and the second split 52 includes a conductive material, such as a metal, and the material of the third split 53 includes an insulating material, such as silicon oxide. The first split 51 and the second split 52 are conductive, and the external connection of the magnetic tunnel junction 30 can be realized. The second split 52 is conductive and the third split 53 is insulating. In the process of etching to form the magnetic tunnel junction 30, the third split 53 is consumed first, and the third split 53 is sputtered to the side wall of the magnetic tunnel junction 30. It has insulating properties and will not conduct the free layer and the reference layer of the magnetic tunnel junction 30, thereby avoiding the short circuit failure of the magnetic tunnel junction 30.

[0069] And when the second split 52 is subsequently consumed, the second split 52 is sputtered onto the third split 53, and will not directly contact the side wall of the magnetic tunnel junction 30, and thus will not conduct the free layer and reference layer of the magnetic tunnel junction 30. That is, the sputtered third split 53 will isolate the sputtered second split 52 and the magnetic tunnel junction 30, thereby further avoiding short circuit failure of the magnetic tunnel junction 30.

[0070] The outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, or the outer peripheral surface of the third body 53 is recessed in the outer peripheral surface of the first body 51. The outer peripheral surface refers to the outer peripheral side wall, and the outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, that is, the outer peripheral surface of the third body 53 smoothly transitions to the outer peripheral surface of the first body 51. For example, the outer peripheral contours of the third body 53 and the first body 51 facing each other completely overlap, that is, the mask layer 50 forms a straight columnar structure. The outer peripheral surface of the third body 53 is recessed in the outer peripheral surface of the first body 51, that is, the mask layer 50 forms a convex structure that is small at the top and large at the bottom. In this way, the outer peripheral contour of the third body 53 will not exceed the outer peripheral contour of the first body 51, and the third body 53 will not increase the critical dimensions of the mask layer 50, thereby avoiding the key dimensions of the formed magnetic tunnel junction 30 from being enlarged.

[0071] In the direction perpendicular to the thickness of the mask layer 50, the relationship between the size of the second sub-body 52 and the size of the third sub-body 53 is not limited. Figure 1 As shown, the direction perpendicular to the thickness of the mask layer 50 is the horizontal direction (X direction). For example, along the direction perpendicular to the thickness of the mask layer 50, the size of the second segment 52 is smaller than the size of the third segment 53. That is, the third segment 53 is thicker, ensuring sufficient consumption during the etching process to form the magnetic tunnel junction 30. In an example where the third segment 53 completely surrounds the second segment 52 and has the same thickness, the size of the third segment 53 along the direction perpendicular to the thickness of the mask layer 50 is twice the thickness of the third segment 53.

[0072] It is understood that the outer circumference of the third body 53 is aligned with the outer circumference of the first body 51, or the outer circumference of the third body 53 is recessed in the outer circumference of the first body 51, and the third body 53 surrounds the second body 52. ​​It can be seen that the orthographic projection of the second body 52 is within the outline of the first body 51, that is, perpendicular to the thickness of the mask layer 50. The size of the second body 52 is smaller than that of the first body 51, and the sum of the size of the second body 52 and the thickness of the third body 53 is equal to or smaller than the size of the first body 51.

[0073] In some possible examples, the third body 53 completely surrounds the second body 52, that is, the third body 53 completely surrounds the second body 52, forming a complete ring. In this way, the third body 53 surrounds the second body 52, and during the etching process of the magnetic tunnel junction 30, it can be better ensured that the third body 53 is etched and consumed first, thereby reducing the etching consumption of the second body 52.

[0074] In some possible examples, along the height direction of the mask layer 50, the size of the first sub-body 51 is smaller than the size of the third sub-body 53, and smaller than the size of the second sub-body 52. ​​The height direction of the mask layer 50 is also the stacking direction of the first sub-body 51 and the second sub-body 52, and is also the height direction of the first sub-body 51, the second sub-body 52, and the third sub-body 53. Figure 1 The Z direction is shown. The height of the first split 51 is less than the height of the third split 53, and the height of the first split 51 is less than the height of the second split 52. For example, the height of the first split 51 is 1 / 3 of the height of the third split 53, or less. In this way, the third split 53 and the second split 52 are higher, and the first split 51 is lower. In the outer peripheral surface of the mask layer 50, the third split 53 accounts for a higher proportion, and the first split 51 accounts for a lower proportion. Therefore, in the process of etching to form the magnetic tunnel junction 30, the sputtered insulating material far exceeds the conductive material, thereby reducing the short circuit of the magnetic tunnel junction 30.

[0075] In some possible examples, the surface of the second split body 52 facing away from the first split body 51 is flush with the surface of the third split body 53 facing away from the first split body 51. Figure 1 As shown by the dashed line, the top surface of the second body 52 is flush with the top surface of the third body 53. That is, along the height of the mask layer 50, the second body 52 and the third body 53 are substantially the same height. Thus, the third body 53 can provide enhanced protection for the second body 52 along the entire height of the mask layer 50, reducing etching consumption of the second body 52. ​​The top surface of the second body 52 is also exposed and electrically conductive with the first body 51, allowing the magnetic tunnel junction 30 to be externally connected through the first and second bodies 51, 52.

[0076] In other possible examples, the third body 53 also covers the surface of the second body 52 facing away from the first body 51, that is, the third body 53 covers the top surface of the second body 52. ​​In this way, the third body 53 covers the second body 52. ​​In the process of etching to form the magnetic tunnel junction 30, the third body 53 on the top surface or side surface of the second body 52 is consumed, that is, after the top surface or side surface of the second body 52 is exposed, it will be etched and consumed, which can reduce the impact of sputtering of the second body 52 on the magnetic tunnel junction 30. In this example, in the process of etching to form the magnetic tunnel junction 30, the third body 53 on the side of the second body 52 facing away from the first body 51 is completely etched and consumed, so that the surface of the second body 52 is exposed and can be electrically connected to the first body 51, so that the magnetic tunnel junction 30 can be externally connected through the first body 51 and the second body 52.

[0077] Continue reading Figure 1, the etching rate of the third split 53 is greater than the etching rate of the first split 51, and greater than the etching rate of the second split 52. That is, the etching selectivity ratio of the third split 53 to the first split 51 is greater than 1, and the etching selectivity ratio of the third split 53 to the second split 52 is greater than 1. For example, the etching selectivity ratio of the third split 53 to the first split 51 is greater than 3, and the etching selectivity ratio of the third split 53 to the second split 52 is greater than 5. Among the first split 51, the second split 52 and the third split 53, the etching rate of the third split 53 is the highest, that is, the third split 53 is easiest to etch. In this way, in the process of etching to form the magnetic tunnel junction 30, the first split 51 and the second split 52 are less likely to be etched and consumed, and the third split 53 is easily etched and consumed, and the first split 51 and the second split 52 are reduced from being etched and sputtered onto the sidewalls of the magnetic tunnel junction 30.

[0078] In some possible embodiments, a mask layer 50 remains on the magnetic tunnel junction 30, and the remaining mask layer 50 includes a third body 53. That is, after etching to form the magnetic tunnel junction 30, a portion of the third body 53 remains, which can minimize the exposure of the first body 51 and the second body 52, thereby reducing the impact of the first body 51 and the second body 52 on the magnetic tunnel junction 30. In addition, the second body 52 or the first body 51 is exposed, for example, the top surface of the second body 52 is exposed, so as to facilitate external connection to the magnetic tunnel junction 30.

[0079] In some possible examples, the first body 51 and the second body 52 form an integral structure; the third body 53 completely covers the outer periphery of the second body 52. ​​In this way, the first body 51 and the second body 52 are made of the same material, such as tantalum or tantalum nitride, which can reduce interlayer separation and have lower contact resistance. The third body 53 completely covers the outer periphery of the second body 52, so that the third body 53 can protect the outer periphery of the second body 52, and better prevent the second body 52 from being etched and sputtered onto the sidewalls of the magnetic tunnel junction 30. At the same time, the surface of the second body 52 facing away from the first body 51 (i.e., the top surface) is exposed, and can be electrically conductive with the first body 51, so that the magnetic tunnel junction 30 can be externally connected through the first body 51 and the second body 52.

[0080] Continue reading Figure 1 Taking a plane perpendicular to the surface of the mask layer 50 as a cross-section, the cross-sectional shape of the third body 53 includes oppositely arranged rectangles, triangles, trapezoids, sectors, or other shapes. That is, the cross-sectional shape of the third body 53 on one side of the second body 52 is correspondingly a rectangle, triangle, trapezoid, sector, or other shape. For example, the cross-sectional shape of the third body 53 includes two axially symmetrical rounded rectangles.

[0081] In some possible examples, the magnetic memory device further includes a spin-orbit moment layer 20, which is disposed below the magnetic tunnel junction 30 and adjacent to the free layer of the magnetic tunnel junction 30. That is, the spin-orbit moment layer 20 is located on the side of the free layer facing away from the reference layer, for example, the spin-orbit moment layer 20 is in direct contact with the free layer. The spin-orbit moment layer 20 is used to generate corresponding polarization currents with write currents in different directions, thereby generating spin torques in different directions. The spin-orbit moment layer 20 can be in the form of an elongated strip or an L-shape, and the embodiment of the present application does not limit the shape of the spin-orbit moment layer 20. For example, the spin-orbit moment layer 20 extends along a first direction, and the first direction is such as Figure 1 X direction shown.

[0082] The spin-orbit moment layer 20 is a single layer or a stacked layer, and the material of the spin-orbit moment layer 20 includes a conductive material with a strong spin-orbit coupling effect. Exemplarily, the material of the spin-orbit moment layer 20 includes one or more of Pt, Pd, Hf, Au, AuPt, PtHf, PtCr, PtMn, FeMn, NiMn, Ta, W, Ir, IrMn, WOx, WN, WON, TaN, TaB, and topological insulators. Topological insulators include Bi x Se 1-x ,Bi x Sb 1-x , (Bi,Sb)2Te3, where x independently satisfies the value of 0.1-0.9.

[0083] In other examples, the magnetic memory device may also utilize a current flowing perpendicularly through the magnetic tunnel junction 30 to allow the reference layer to filter spins. The spin-polarized electrons in the reference layer directly exert torque on the free layer. That is, the magnetic memory device is a spin-transfer torque device.

[0084] In some possible examples, the magnetic memory device further includes a substrate 10, with the magnetic tunnel junction 30 disposed on the substrate 10. For example, the magnetic tunnel junction 30 is located on the spin-orbit moment layer 20, which is located on the substrate 10. In another example, the magnetic tunnel junction 30 is located directly on the substrate 10. The substrate 10 supports the structures thereon and is made of a semiconductor material such as silicon, germanium, silicon-germanium, silicon-on-insulator (SOI), or germanium-on-insulator (SOG).

[0085] A conductive via (not shown) is provided in the substrate 10, and the magnetic tunnel junction 30 is located directly on the substrate 10. The conductive via in the substrate 10 is located below the magnetic tunnel junction 30 to electrically connect the magnetic tunnel junction 30. Alternatively, the magnetic tunnel junction 30 is located on the spin-orbit moment layer 20, and at least two conductive vias (not shown) are provided in the substrate 10, at least two of which are located on either side of the spin-orbit moment layer 20. The orthographic projection of the magnetic tunnel junction 30 on the substrate 10 does not overlap with the conductive vias, that is, the orthographic projection of the magnetic tunnel junction 30 on the substrate 10 is spaced apart from the conductive vias.

[0086] The magnetic memory device provided in the embodiment of the present application includes a magnetic tunnel junction 30, which is formed by etching using a mask layer 50 as a mask. The mask layer 50 includes a first body 51, a second body 52, and a third body 53. The second body 52 is arranged on a side of the first body 51 away from the magnetic tunnel junction 30, and the third body 53 surrounds the second body 52. ​​The first body 51 and the second body 52 are conductive, while the third body 53 is insulating. During the etching process to form the magnetic tunnel junction 30, the third body 53 is consumed first and then sputtered onto the sidewalls of the magnetic tunnel junction 30. The third body 53 has insulating properties and does not conduct electricity between the free layer and the reference layer of the magnetic tunnel junction 30, thereby preventing the magnetic tunnel junction 30 from short-circuiting and failing. When the second body 52 is subsequently consumed, it is sputtered onto the third body 53 and does not directly contact the sidewalls of the magnetic tunnel junction 30, thereby preventing conduction between the free layer and the reference layer of the magnetic tunnel junction 30. That is, the sputtered third body 53 isolates the sputtered second body 52 from the magnetic tunnel junction 30, thereby further preventing short-circuit failure of the magnetic tunnel junction 30. The outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, or the outer peripheral surface of the third body 53 is recessed into the outer peripheral surface of the first body 51. The outer peripheral contour of the third body 53 does not exceed the outer peripheral contour of the first body 51. The third body 53 does not increase the critical dimensions of the mask layer 50, thereby preventing the critical dimensions of the formed magnetic tunnel junction 30 from being enlarged.

[0087] See Figures 2 to 12 , an embodiment of the present application further provides a method for manufacturing a magnetic memory device, the manufacturing method comprising the following steps:

[0088] Step S100: forming a magnetic tunnel junction stack layer.

[0089] The magnetic tunnel junction stack layer 31 is used to form the magnetic tunnel junction 30. The magnetic tunnel junction stack layer 31 can be formed by a deposition process, including but not limited to physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc.

[0090] The magnetic tunnel junction stack 31 includes a free initial layer, a barrier initial layer, and a reference initial layer stacked in sequence. The free initial layer is used to form a free layer, and its magnetization direction can be changed. The reference initial layer is used to form a reference layer, and its magnetization direction is fixed. The materials of the free initial layer and the reference initial layer include ferromagnetic materials, for example, at least one of Co, Fe, B, Ni, Ru, Ir, and Pt. The materials of the free initial layer and the reference initial layer can be the same or different. The barrier initial layer is used to form a barrier layer to isolate the free layer and the reference layer. The material of the barrier initial layer includes an insulating material, for example, at least one of MgO, Al2O3, and SiO2.

[0091] In some possible examples, the magnetic tunnel junction stack layer 31 is disposed on the spin-orbit moment initialization layer 21, the free initialization layer is adjacent to the spin-orbit moment initialization layer 21, and the spin-orbit moment initialization layer 21 is used to form the spin-orbit moment layer 20 (see Figure 1 ). The spin-orbit moment initial layer 21 can be a single layer or a stacked layer. The material of the spin-orbit moment initial layer 21 includes a conductive material with a strong spin-orbit coupling effect. Exemplarily, the material of the spin-orbit moment initial layer 21 includes one or more of Pt, Pd, Hf, Au, AuPt, PtHf, PtCr, PtMn, FeMn, NiMn, Ta, W, Ir, IrMn, WOx, WN, WON, TaN, TaB, and topological insulators. Topological insulators include Bi x Se 1-x ,Bi x Sb 1-x , (Bi,Sb)2Te3, where x independently satisfies the value of 0.1-0.9.

[0092] In some possible examples, the spin-orbit moment initialization layer 21 is formed on the substrate 10, that is, the substrate 10, the spin-orbit moment initialization layer 21 and the magnetic tunnel junction stacking layer 31 are stacked in sequence. For example, the spin-orbit moment initialization layer 21 and the magnetic tunnel junction stacking layer 31 are sequentially deposited on the substrate 10. The substrate 10 supports the structure thereon, and the material of the substrate 10 includes semiconductor materials, such as silicon, germanium, silicon-germanium, silicon on insulator, or germanium on insulator. Conductive through-holes can be formed in the substrate 10 to achieve external connection. In other possible examples, the magnetic tunnel junction stacking layer 31 can be formed directly on the substrate 10.

[0093] Step S200: forming a mask layer, the mask layer being formed on one side of the magnetic tunnel junction stack layer; the mask layer comprising: a first split, a second split arranged on a side of the first split away from the magnetic tunnel junction, and a third split surrounding the second split; the first split and the second split are conductive, and the third split is insulating; wherein the outer peripheral surface of the third split is aligned with the outer peripheral surface of the first split, or the outer peripheral surface of the third split is recessed in the outer peripheral surface of the first split.

[0094] The mask layer 50 is located on one side of the magnetic tunnel junction stacking layer 31 and is stacked on the magnetic tunnel junction stacking layer 31. Exemplarily, the mask layer 50 is located on the side of the magnetic tunnel junction stacking layer 31 away from the substrate 10, for example, on the top surface of the magnetic tunnel junction stacking layer 31. The mask layer 50 includes a first split 51, a second split 52 and a third split 53. The second split 52 is located on the side of the first split 51 away from the magnetic tunnel junction 30, and the third split 53 surrounds the second split 52. The third split 53 and the second split 52 are arranged on the same side, that is, the third split 53 is also located on the side of the first split 51 away from the magnetic tunnel junction 30. Figure 1 As shown, the second body 52 and the third body 53 are both located above the first body 51, and along the X direction shown in FIG1 , the second body 52 is located inside the third body 53. The first body 51 forms the lower portion of the mask layer 50, and the second body 52 and the third body 53 form the upper portion of the mask layer 50.

[0095] The first split 51 and the second split 52 can be cylindrical, such as a circular cylinder, an elliptical cylinder or a rectangular cylinder, and the shapes of the first split 51 and the second split 52 can be the same or different. The third split 53 surrounds the second split 52, and its shape can be a ring, such as a circular ring, an elliptical ring or a rectangular ring. The specific shapes of the first split 51, the second split 52 and the third split 53 can be selected according to the shape requirements of the magnetic tunnel junction 30. Exemplarily, the first split 51 and the second split 52 are both elliptical cylinders, and the third split 53 is an elliptical ring; another exemplary embodiment, the first split 51 is an elliptical cylinder, the second split 52 is a circular cylinder, and the third split 53 is an annular cylinder with an outer elliptical and an inner circular shape.

[0096] The first body 51 and the second body 52 are conductive, and the third body 53 is insulating. Exemplarily, the material of the first body 51 and the second body 52 includes a conductive material, such as a metal, and the material of the third body 53 includes an insulating material, such as silicon oxide. The first body 51 and the second body 52 are conductive, which can realize the external connection of the magnetic tunnel junction 30. The second body 52 is conductive and the third body 53 is insulating. In the process of etching to form the magnetic tunnel junction 30, the third body 53 is consumed first. The third body 53 is sputtered to the side wall of the magnetic tunnel junction 30. It has insulating properties and will not conduct the free layer and the reference layer of the magnetic tunnel junction 30, thereby avoiding short circuit failure of the magnetic tunnel junction 30. And when the second split 52 is subsequently consumed, the second split 52 is sputtered onto the third split 53, and will not directly contact the side wall of the magnetic tunnel junction 30, and thus will not conduct the free layer and reference layer of the magnetic tunnel junction 30. That is, the sputtered third split 53 will isolate the sputtered second split 52 and the magnetic tunnel junction 30, thereby further avoiding short circuit failure of the magnetic tunnel junction 30.

[0097] The outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, or the outer peripheral surface of the third body 53 is recessed in the outer peripheral surface of the first body 51. The outer peripheral surface refers to the outer peripheral side wall, and the outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, that is, the outer peripheral surface of the third body 53 smoothly transitions to the outer peripheral surface of the first body 51. For example, the outer peripheral contours of the third body 53 and the first body 51 facing each other completely overlap, that is, the mask layer 50 forms a straight columnar structure. The outer peripheral surface of the third body 53 is recessed in the outer peripheral surface of the first body 51, that is, the mask layer 50 forms a convex structure that is small at the top and large at the bottom. In this way, the outer peripheral contour of the third body 53 will not exceed the outer peripheral contour of the first body 51, and the third body 53 will not increase the critical dimensions of the mask layer 50, thereby avoiding the critical dimensions of the formed magnetic tunnel junction 30 from being enlarged.

[0098] It is understood that the outer circumference of the third body 53 is aligned with the outer circumference of the first body 51, or the outer circumference of the third body 53 is recessed in the outer circumference of the first body 51, and the third body 53 surrounds the second body 52. ​​It can be seen that the orthographic projection of the second body 52 is within the outline of the first body 51, that is, the size of the second body 52 is smaller than that of the first body 51, and the sum of the size of the second body 52 and the thickness of the third body 53 is equal to or smaller than the size of the first body 51.

[0099] In some possible examples, the surface of the second split body 52 facing away from the first split body 51 is flush with the surface of the third split body 53 facing away from the first split body 51. Figure 2As shown, the top surface of the second body 52 is flush with the top surface of the third body 53. That is, along the height direction of the mask layer 50, the first body 51 and the third body 53 are substantially the same height. In this way, the third body 53 can provide improved protection for the second body 52 along the entire height direction of the mask layer 50, reducing etching consumption of the second body 52. ​​The top surface of the second body 52 is also exposed and can be electrically connected to the first body 51, so that the magnetic tunnel junction 30 can be externalized through the first and second bodies 51, 52.

[0100] In other possible examples, the third body 53 also covers the surface of the second body 52 facing away from the first body 51, that is, the third body 53 covers the top surface of the second body 52. ​​In this way, the third body 53 covers the second body 52. ​​In the process of etching to form the magnetic tunnel junction 30, the third body 53 on the top surface or side surface of the second body 52 is consumed, that is, after the top surface or side surface of the second body 52 is exposed, it will be etched and consumed, which can reduce the impact of sputtering of the second body 52 on the magnetic tunnel junction 30. In this example, in the process of etching to form the magnetic tunnel junction 30, the third body 53 on the side of the second body 52 facing away from the first body 51 is completely etched and consumed, so that the surface of the second body 52 is exposed and can be electrically connected to the first body 51, so that the magnetic tunnel junction 30 can be externally connected through the first body 51 and the second body 52.

[0101] In some possible examples, the third body 53 completely surrounds the second body 52, that is, the third body 53 completely surrounds the second body 52, forming a complete ring. In this way, the third body 53 surrounds the second body 52, and during the etching process of the magnetic tunnel junction 30, it can be better ensured that the third body 53 is etched and consumed first, thereby reducing the etching consumption of the second body 52.

[0102] In some possible examples, along the height direction of the mask layer 50, the size of the first sub-body 51 is smaller than the size of the third sub-body 53, and smaller than the size of the second sub-body 52. ​​The height direction of the mask layer 50 is also the stacking direction of the first sub-body 51 and the second sub-body 52, and is also the height direction of the first sub-body 51, the second sub-body 52, and the third sub-body 53. Figure 1 The Z direction is shown. The height of the first split 51 is less than the height of the third split 53, and the height of the first split 51 is less than the height of the second split 52. For example, the height of the first split 51 is 1 / 3 of the height of the third split 53, or less. In this way, the third split 53 and the second split 52 are higher, and the first split 51 is lower. In the outer peripheral surface of the mask layer 50, the third split 53 accounts for a higher proportion, and the first split 51 accounts for a lower proportion. Therefore, in the process of etching to form the magnetic tunnel junction 30, the sputtered insulating material far exceeds the conductive material, thereby reducing the short circuit of the magnetic tunnel junction 30.

[0103] Step S300: using the mask layer as a mask, etching the magnetic tunnel junction stack layer to form a magnetic tunnel junction.

[0104] See Figure 6 and Figure 7 ,as well as Figure 11 and Figure 12 The magnetic tunnel junction stack layer 31 is etched, for example, by ion beam etching (IBE), which uses a high-energy ion beam to physically bombard the surface of the magnetic tunnel junction stack layer 31, removing areas not covered by the mask layer 50 and retaining areas covered by the mask layer 50. The retained magnetic tunnel junction stack layer 31 forms the magnetic tunnel junction 30. Exemplarily, when etching to form the magnetic tunnel junction 30, the etching stops at the upper surface of the spin-orbit moment initiation layer 21, that is, the upper surface of the spin-orbit moment initiation layer 21 is exposed, and the etching stops.

[0105] In some possible exemplary embodiments, the etching rate of the third body 53 is greater than the etching rate of the first body 51, and greater than the etching rate of the second body 52. ​​That is, the etching selectivity ratio of the third body 53 to the first body 51 is greater than 1, and the etching selectivity ratio of the third body 53 to the second body 52 is greater than 1. For example, the etching selectivity ratio of the third body 53 to the first body 51 is greater than 3, and the etching selectivity ratio of the third body 53 to the second body 52 is greater than 5. Among the first body 51, the second body 52, and the third body 53, the etching rate of the third body 53 is the highest, that is, the third body 53 is the easiest to etch. In this way, in the process of etching to form the magnetic tunnel junction 30, the first body 51 and the second body 52 are less likely to be etched and consumed, while the third body 53 is easily etched and consumed, and the first body 51 and the second body 52 are etched and sputtered onto the sidewalls of the magnetic tunnel junction 30.

[0106] In particular, along the height direction of the mask layer 50, the size of the magnetic tunnel junction stack 31 is smaller than the size of the third body 53 and smaller than the size of the second body 52, so that a portion of the third body 53 is retained after the magnetic tunnel junction 30 is formed. That is, after etching to form the magnetic tunnel junction 30, a portion of the third body 53 still remains, and the outer peripheral surface of the second body 52 is still at least partially wrapped by the third body 53, which can minimize the exposure of the first body 51 and the second body 52, thereby reducing the impact of the first body 51 and the second body 52 on the magnetic tunnel junction 30. In addition, the second body 52 or the first body 51 is exposed, for example, the top surface of the second body 52 or the top surface of the first body 51 is exposed, so as to facilitate external connection to the magnetic tunnel junction 30.

[0107] In some possible examples, when etching the magnetic tunnel junction stack layer 31, an angle is formed between the etching direction and the normal direction of the upper surface of the mask layer 50. The etching direction refers to the spatial orientation of material removal during the etching process of the magnetic tunnel junction stack layer 31, for example, the bombardment direction of ions on the magnetic tunnel junction stack layer 31. The angle is formed between the etching direction and the normal direction of the upper surface of the mask layer 50, and the angle is, for example, 15° to 45°. Figure 1 As shown, the normal direction of the upper surface of the mask layer 50 is, for example, the height direction of the mask layer 50, i.e., the vertical direction (Z direction). The etching direction is the E direction, which is oblique, i.e., tilted relative to the vertical direction. In this way, during the etching process to form the magnetic tunnel junction 30, residues on the sidewalls of the magnetic tunnel junction 30 can also be removed, thereby improving the performance and yield of the magnetic tunnel junction 30.

[0108] The method for manufacturing a magnetic memory device provided in an embodiment of the present application includes: forming a magnetic tunnel junction stack 31; forming a mask layer 50, the mask layer 50 being formed on one side of the magnetic tunnel junction stack 31; and etching the magnetic tunnel junction stack 31 using the mask layer 50 as a mask to form the magnetic tunnel junction 30. The mask layer 50 includes: a first body 51, a second body 52 disposed on a side of the first body 51 away from the magnetic tunnel junction 30, and a third body 53 surrounding the second body 52; the first body 51 and the second body 52 are conductive, while the third body 53 is insulated; and the outer peripheral surface of the third body 53 is aligned with the outer peripheral surface of the first body 51, or the outer peripheral surface of the third body 53 is recessed from the outer peripheral surface of the first body 51. During the etching process to form the magnetic tunnel junction 30, the insulating third body 53 is consumed first. The third body 53 is sputtered onto the sidewalls of the magnetic tunnel junction 30. Since it is insulating, it will not conduct the free layer and reference layer of the magnetic tunnel junction 30, thereby preventing the magnetic tunnel junction 30 from short-circuiting and failing. Furthermore, when the second body 52 is subsequently consumed, the second body 52 is sputtered onto the third body 53. It will not directly contact the sidewalls of the magnetic tunnel junction 30, thereby preventing the free layer and reference layer of the magnetic tunnel junction 30 from conducting. That is, the sputtered third body 53 will isolate the sputtered second body 52 from the magnetic tunnel junction 30, thereby further preventing the magnetic tunnel junction 30 from short-circuiting and failing. Furthermore, the outer contour of the third body 53 will not exceed the outer contour of the first body 51. The third body 53 will not increase the critical dimensions of the mask layer 50, thereby preventing the critical dimensions of the formed magnetic tunnel junction 30 from being enlarged.

[0109] In some possible implementations, see Figures 3 to 6, forming a mask layer 50, including: patterning the initial mask layer 54 to form a mask column 55; forming a sacrificial layer 60, the sacrificial layer 60 covers the top surface and part of the side surface of the mask column 55, and the mask column 55 is partially exposed on the side away from the magnetic tunnel junction stack layer 31; modifying the exposed side surface of the mask column 55 to form a third split 53, the mask column 55 in contact with the side surface of the third split 53 forms a second split 52, and the mask column 55 located on the side of the third split 53 and the second split 52 close to the magnetic tunnel junction stack layer 31 forms a first split 51.

[0110] like Figure 3 As shown, an initial mask layer 54 is deposited and formed. The initial mask layer 54 is a single layer structure and is located on the side of the magnetic tunnel junction stack 31 facing away from the substrate 10. The initial mask layer 54 can be a single layer or a stack of layers. The initial mask layer 54 is conductive, that is, the material of the initial mask layer 54 is a conductive material, which includes but is not limited to metals and their alloys. Exemplarily, the material of the initial mask layer 54 is tantalum or tantalum nitride.

[0111] like Figure 3 and Figure 4 As shown, the initial mask layer 54 is patterned, and the etching stops at the film layer below the initial mask layer 54. The patterned initial mask layer 54 forms mask pillars 55. One or more mask pillars 55 are provided as needed, and each mask pillar 55 is spaced apart from each other. The mask pillars 55 can be cylindrical, elliptical, rectangular, etc., and their shapes are compatible with, for example, the same as, the shape of the magnetic tunnel junction 30 to be formed.

[0112] like Figure 4 As shown, the sacrificial layer 60 is deposited, for example, by vertical deposition, that is, the deposition direction is perpendicular to the top surface of the mask pillar 55. The deposition thickness of the sacrificial layer 60 is less than the height of the initial mask layer 54, and the sacrificial layer 60 does not form a continuous film layer. The sacrificial layer 60 covers the top surface of the mask pillar 55 and the portion of the outer peripheral sidewall of the mask pillar 55 adjacent to the substrate 10, that is, the portion of the outer peripheral sidewall of the mask pillar 55 close to the top surface is exposed. The height of the exposed sidewall in the mask pillar 55 is related to the deposition thickness of the sacrificial layer 60. The greater the deposition thickness of the sacrificial layer 60, the smaller the height of the exposed sidewall in the mask pillar 55. The material of the sacrificial layer 60 can be a hard mask material, for example, including silicon nitride, silicon oxynitride, silicon carbide nitride, etc.

[0113] like Figure 5As shown, the exposed side of the mask column 55 is modified so that part of the mask column is changed from conductive to insulating, and the mask column 55 forms a third body 53. The modification treatment can be oxidation treatment, nitridation treatment, ion implantation treatment, etc. During the oxidation treatment, an oxygen-rich environment is constructed. For example, it is placed in an etching chamber and blown with oxygen at a flow rate of 200 sccm for 20 minutes; for another example, it is placed in a plasma etching chamber and modified with oxygen plasma. The conditions for generating oxygen plasma are plasma source power of 100-300W, oxygen flow rate of 100-500 sccm, bias power of 0W, and placed for 1-5 minutes. Similarly, the nitridation treatment is the same as the above-mentioned oxidation treatment. Ion implantation is to place it in an ion implanter. The implanted ions include hydrogen, oxygen, nitrogen, helium, or one or more. The ion implantation depth is controlled by regulating the implantation energy. The mask layer 50 on the same layer as the third body 53 forms a second body 52. ​​The third body 53 surrounds the second body 52 and contacts the side of the second body 52. The remaining mask pillars 55 form a first sub-body 51, which is located on the side of the third sub-body 53 and the second sub-body 52 close to the magnetic tunnel junction stack layer 31. The first sub-body 51 and the second sub-body 52 remain conductive. The third sub-body 53, the second sub-body 52, and the first sub-body 51 form a mask layer 50.

[0114] like Figure 6 and Figure 7 As shown, the remaining sacrificial layer 60 is removed, for example, by etching the sacrificial layer 60 using reactive ion etching (RIE) to expose the mask pillars 55 so that the magnetic tunnel junction stack layer 31 can be subsequently etched.

[0115] In some other possible implementations, see Figures 8 to 11 , forming a mask layer 50, including: patterning the initial mask layer 54 to form a groove 56 in the initial mask layer 54; forming a third split 53, the third split 53 covering the sidewall of the groove 56; forming a second split 52, the second split 52 filling the area enclosed by the third split 53; removing part of the initial mask layer 54, retaining the third split 53 and the initial mask layer 54 of the second split 52 close to the magnetic tunnel junction stack layer 31, to form a first split 51.

[0116] like Figure 3 As shown, an initial mask layer 54 is deposited and formed. The initial mask layer 54 is a single layer structure and is located on the side of the magnetic tunnel junction stack 31 facing away from the substrate 10. The initial mask layer 54 can be a single layer or a stack of layers. The initial mask layer 54 is conductive, that is, the material of the initial mask layer 54 is a conductive material, which includes but is not limited to metals and their alloys. Exemplarily, the material of the initial mask layer 54 is tantalum or tantalum nitride.

[0117] like Figure 3 and Figure 8As shown, the initial mask layer 54 is patterned to form a groove 56 in the initial mask layer 54. The bottom wall of the groove 56 is located in the initial mask layer 54, that is, the groove 56 does not penetrate the initial mask layer 54, and the depth of the groove 56 is less than the height of the initial mask layer 54. One or more grooves 56 are provided as needed, and each groove 56 is spaced apart from each other. The specific shape of the groove 56 is not limited and can be a cylinder, an elliptical cylinder, a rectangular cylinder, etc., and its shape is compatible with, for example, the same as, the shape of the magnetic tunnel junction 30 to be formed.

[0118] like Figure 9 As shown, a third body 53 is deposited on the sidewall of the groove 56. The third body 53 is insulated. The third body 53 does not fill the groove 56, and the bottom wall of the groove 56 is still partially exposed. In some possible implementations, an insulating material layer is deposited. The insulating material layer can be a non-conductive oxide layer, a nitride layer, or a carbide layer. The insulating material layer conformally covers the initial mask layer 54 to form a continuous film layer. For example, the insulating material layer covers the sidewalls and bottom wall of the groove 56, as well as the top surface of the initial mask layer 54 outside the groove 56. The insulating material layer is etched back to remove the top surface of the initial mask layer 54 and part of the insulating material layer on the bottom wall of the groove 56, retaining the insulating material layer on the sidewall of the groove 56, and the retained insulating material layer forms the third body 53.

[0119] like Figure 9 and Figure 10 As shown, a second body 52 is deposited. The second body 52 is conductive and fills the remaining groove 56. The second body 52 is in direct contact with the initial mask layer 54. In some possible implementations, a conductive material layer is deposited to fill the remaining groove 56 and cover the initial mask layer 54 and the top surface of the third body 53. The conductive material layer is planarized, such as by chemical mechanical polishing (CMP), stopping at the initial mask layer 54. The remaining conductive material layer forms the second body 52. ​​The top surfaces of the second body 52 and the third body 53 are flush with the top surface of the initial mask layer 54.

[0120] like Figure 10 and Figure 11 As shown, the initial mask layer 54 is patterned, and etching stops at the film layer below the initial mask layer 54. The initial mask layer 54 below the second sub-body 52 and the third sub-body 53 is retained, and this portion of the initial mask layer 54 forms the first sub-body 51. After patterning, the outer periphery of the third sub-body 53 is exposed. The third sub-body 53, the second sub-body 52, and the first sub-body 51 form the mask layer 50.

[0121] In the above two embodiments, the first body 51 and the second body 52 form an integral structure; the third body 53 completely covers the outer peripheral surface of the second body 52. ​​In this way, the first body 51 and the second body 52 are made of the same material, such as tantalum or tantalum nitride, which can reduce interlayer separation and have lower contact resistance. The third body 53 completely covers the outer peripheral surface of the second body 52, so that the third body 53 can protect the outer peripheral surface of the second body 52, and better prevent the second body 52 from being etched and sputtered onto the sidewalls of the magnetic tunnel junction 30. At the same time, the surface of the second body 52 facing away from the first body 51 (i.e., the top surface) is exposed, and can be electrically conductive with the first body 51, so that the magnetic tunnel junction 30 can be externally connected through the first body 51 and the second body 52.

[0122] In the above two embodiments, the cross-sectional shape of the third body 53, taken along a plane perpendicular to the top surface of the mask pillar 55, includes oppositely arranged rectangles, triangles, trapezoids, or other shapes. That is, the cross-sectional shape of the third body 53 on one side of the second body 52 corresponds to a rectangle, triangle, trapezoid, or other shape. For example, the cross-sectional shape of the third body 53 includes two axially symmetrical rectangles.

[0123] In the above two embodiments, Figures 3 to 12 As shown, an etch-stop layer 40 is further formed between the initial mask layer 54 and the magnetic tunnel junction stack layer 31. That is, the magnetic tunnel junction stack layer 31, the etch-stop layer 40, and the initial mask layer 54 are stacked in sequence. The etch-stop layer 40 is used to protect the magnetic tunnel junction stack layer 31 during the etching process of the initial mask layer 54 to prevent the initial mask layer 54 from being overetched and damaging the magnetic tunnel junction stack layer 31. The etch-stop layer 40 is conductive and can be made of titanium nitride, tungsten, ruthenium, cobalt, etc.

[0124] In the description of the embodiments of the present application, it should be understood that, unless otherwise expressly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. The orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application. In the description of this application, the meaning of "multiple" is two or more, unless otherwise precisely and specifically specified.

[0125] The terms "first," "second," "third," "fourth," and the like (if any) in the specification and claims of this application and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0126] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A magnetic storage device, characterized in that: include: a magnetic tunnel junction, wherein the magnetic tunnel junction is formed by etching using the mask layer as a mask; The mask layer includes: a first split body, a second split body provided on a side of the first split body away from the magnetic tunnel junction, and a third split body surrounding the second split body; The first split body and the second split body are conductive, and the third split body is insulated; The outer peripheral surface of the third split body is aligned with the outer peripheral surface of the first split body, or the outer peripheral surface of the third split body is recessed into the outer peripheral surface of the first split body.

2. The magnetic memory device according to claim 1, wherein Along the height direction of the mask layer, the size of the first split body is smaller than the size of the third split body, and smaller than the size of the second split body.

3. The magnetic memory device according to claim 1, wherein A surface of the second split body facing away from the first split body is flush with a surface of the third split body facing away from the first split body.

4. The magnetic memory device according to any one of claims 1 to 3, wherein: The etching rate of the third body is greater than the etching rate of the first body, and greater than the etching rate of the second body.

5. The magnetic memory device according to any one of claims 1 to 3, wherein: The first split body and the second split body form an integrated structure; The third split body completely covers the outer peripheral surface of the second split body.

6. A method for manufacturing a magnetic memory device, characterized in that: include: forming a magnetic tunnel junction stack layer; forming a mask layer, wherein the mask layer is formed on one side of the magnetic tunnel junction stack layer; The mask layer includes: a first split body, a second split body provided on a side of the first split body away from the magnetic tunnel junction, and a third split body surrounding the second split body; The first split body and the second split body are conductive, and the third split body is insulated; Wherein, the outer peripheral surface of the third split body is aligned with the outer peripheral surface of the first split body, or the outer peripheral surface of the third split body is recessed into the outer peripheral surface of the first split body; The mask layer is used as a mask to etch the magnetic tunnel junction stack layer to form a magnetic tunnel junction.

7. The production method according to claim 6, characterized in that: Forming the mask layer includes: patterning the initial mask layer to form mask pillars; forming a sacrificial layer, wherein the sacrificial layer covers a top surface and a portion of a side surface of the mask pillar, and a portion of the side surface of the mask pillar away from the magnetic tunnel junction stack layer is exposed; The exposed side of the mask column is modified to form the third split, the mask column in contact with the side of the third split forms the second split, and the mask column located on the side of the third split and the second split close to the magnetic tunnel junction stacking layer forms the first split.

8. The production method according to claim 7, characterized in that: Along the height direction of the mask layer, the size of the magnetic tunnel junction stack layer is smaller than the size of the third sub-body and smaller than the size of the second sub-body, so that a portion of the third sub-body is retained after the magnetic tunnel junction is formed.

9. The manufacturing method according to claim 6, characterized in that: Forming the mask layer includes: patterning the initial mask layer to form grooves in the initial mask layer; forming a third split body, wherein the third split body covers the side wall of the groove; forming a second split body, wherein the second split body fills the area enclosed by the third split body; A portion of the initial mask layer is removed, and the initial mask layer on a side of the third split body and the second split body close to the magnetic tunnel junction stack layer is retained to form the first split body.

10. The production method according to any one of claims 7 to 9, characterized in that: When etching the magnetic tunnel junction stacked layer, an angle is formed between the etching direction and the normal direction of the upper surface of the mask layer.

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