Magnetic memory and preparation method thereof

Abstract

The invention provides a magnetic memory and a preparation method thereof. The magnetic memory comprises a plurality of memory units, at least part of the memory units are arranged along a first direction, and each memory unit comprises a magnetic tunnel junction; at least part of the magnetic shielding structure is located between the adjacent storage units in the first direction, and the magnetic shielding structure and the adjacent storage units are arranged at intervals; wherein the magnetic shielding structures and the adjacent storage units are arranged at intervals. Due to the fact that the magnetic shielding structure is arranged between every two adjacent storage units, the storage area can be saved through the design, meanwhile, the magnetic shielding structures can prevent the storage units from making contact with the magnetic shielding structures to cause short circuit, and the storage units have the anti-magnetic characteristic of an opposite internal magnetic field. Therefore, the magnetic memory has the diamagnetic properties of a vertical magnetic field and an in-plane magnetic field, the diamagnetic capability of the magnetic memory is improved, and the reliability of the magnetic memory in a magnetic field environment is further improved.

Description

Technical Field

[0001] The present application relates to semiconductor manufacturing, and in particular, to a magnetic memory and a method for preparing the same. Background Art

[0002] At present, chips with magnetic tunnel junctions as basic units, such as magnetic random access memory (Magnetic RAM, MRAM) chips or magnetic tunnel resistor (Tunnel Magneto Resistance, TMR) magnetic sensor chips, are extremely sensitive to interference from external magnetic fields. Under normal circumstances, chips with magnetic tunnel junctions as units should be configured with structures with certain anti-magnetic properties to improve the reliability of the chip in a magnetic field environment; manufacturing a magnetic shielding structure near the magnetic tunnel junction is one of the common magnetic shielding technology routes for MRAM. At present, the common magnetic shielding scheme has a large difference in its microscopic magnetization curve compared to the macroscopic situation. It is difficult to have both the anti-magnetic properties of the perpendicular magnetic field and the in-plane magnetic field, and it is easy to show magnetic concentration characteristics. Summary of the invention

[0003] The present application provides a magnetic memory and a preparation method thereof to solve the problem in the related art that the magnetic memory is difficult to have both the antimagnetic properties of the perpendicular magnetic field and the in-plane magnetic field and occupies a large storage area.

[0004] According to one aspect of the present application, a magnetic memory is provided, comprising: a plurality of memory cells, at least some of which are arranged along a first direction, each memory cell comprising a magnetic tunnel junction; a magnetic shielding structure, at least part of which is located between adjacent memory cells along the first direction, the magnetic shielding structure being spaced apart from the adjacent memory cells.

[0005] Optionally, each storage cell further includes a top electrode and a bottom electrode, which are located on opposite sides of the magnetic tunnel junction along a second direction, and the second direction is perpendicular to the first direction. The magnetic shielding structure includes: magnetic shielding side walls, which are located on both sides of each storage cell along the first direction; and a magnetic shielding top layer, which is located on a side of each top electrode away from the magnetic tunnel junction.

[0006] Optionally, the magnetic shielding sidewall has a first surface close to the top electrode and a second surface close to the bottom electrode, the first surface and the second surface are opposite surfaces of the magnetic shielding sidewall, and the magnetic shielding top layer has a third surface and a fourth surface relative to each other, the third surface is located on the side of the fourth surface away from the storage unit, wherein: the maximum vertical distance between the first surface and the magnetic tunnel junction is H1, the maximum vertical distance between the third surface and the magnetic tunnel junction is H2, H1<H2; or the first surface and the third surface are coplanar; or the minimum vertical distance between the first surface and the magnetic tunnel junction is H1, the minimum vertical distance between the third surface and the magnetic tunnel junction is H2, H1>H2.

[0007] Optionally, the magnetic memory also includes a bit line extending along the first direction, the bit line is located on a side of the multiple magnetic shielding top layers away from the storage unit, and the magnetic shielding side wall has a first projection on the bit line, wherein: the first projection is a rectangle; or the first projection is a closed figure formed by two symmetrical curves connected end to end; or the first projection is a quadrilateral formed by alternating two first side lines and two second side lines, the first side line is a curve protruding toward the inside of the quadrilateral, the second side line is a straight line, and the first side lines of the same quadrilateral are distributed along the first direction.

[0008] Optionally, a vertical distance between the second surface and the top electrode is H3, the bottom electrode has a fifth surface close to the magnetic tunnel junction, a vertical distance between the fifth surface and the top electrode is H4, and H3≥H4.

[0009] Optionally, the magnetic memory further includes: a word line located at a side of each memory cell away from the bit line, and the word line extends along a third direction, which is perpendicular to the second direction.

[0010] Optionally, the memory cell further includes: a barrier layer located on a side of each top electrode away from the magnetic tunnel junction.

[0011] According to another aspect of the present application, a method for preparing a magnetic memory is provided, comprising the following steps: providing a substrate having a plurality of memory cells on the substrate, at least some of the memory cells being arranged along a first direction, and each memory cell comprising a magnetic tunnel junction; forming a magnetic shielding structure on the substrate so that at least part of the magnetic shielding structure is located between adjacent memory cells along the first direction, and the magnetic shielding structure is spaced apart from the adjacent memory cells.

[0012] Optionally, before the step of forming the above-mentioned magnetic shielding structure on the substrate, the preparation method also includes: forming a first insulating layer covering the storage unit on the substrate so that part of the first insulating layer fills between adjacent storage units; etching the first insulating layer to remove the first insulating layer located on the storage unit, and forming grooves between adjacent storage units. In the step of forming the magnetic shielding structure, soft magnetic material is deposited on the substrate so that part of the soft magnetic material fills in the groove to form a magnetic shielding side wall, and the remaining soft magnetic material is located on the storage unit to form a magnetic shielding top layer.

[0013] Optionally, the preparation method further includes: covering the surface of the magnetic shielding structure with a non-magnetic metal layer; and performing a planarization process on the non-magnetic metal layer to form a bit line.

[0014] Through the technical solution of the present application, a magnetic memory is provided, wherein at least part of the memory cells are arranged along a first direction, each memory cell includes a magnetic tunnel junction, and at least part of the magnetic shielding structure is located between adjacent memory cells along the first direction. Since there is a magnetic shielding structure between each adjacent memory cell, magnetic concentration characteristics can be avoided; two adjacent memory cells can share the magnetic shielding structure located between them, and this shared design can save storage area; and since the above-mentioned magnetic shielding structure is arranged at intervals from adjacent memory cells, the memory cell can be prevented from contacting the magnetic shielding structure and causing a short circuit, so that the memory cell has anti-magnetic characteristics against in-plane magnetic fields, so that the magnetic memory can have anti-magnetic properties of both perpendicular magnetic fields and in-plane magnetic fields, improve its anti-magnetic ability, and then improve the reliability of the magnetic memory in a magnetic field environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A three-dimensional schematic diagram of a magnetic memory structure provided in an embodiment of the present application is shown;

[0017] Figure 2 A schematic cross-sectional structure diagram of a magnetic memory structure provided in an embodiment of the present application is shown;

[0018] Figure 3 A cross-sectional structural schematic diagram of another magnetic memory structure provided in an embodiment of the present application is shown;

[0019] Figure 4 A cross-sectional structural schematic diagram of another magnetic memory structure provided in an embodiment of the present application is shown;

[0020] Figure 5 A schematic diagram of a top view of a magnetic shielding side wall in a magnetic memory structure provided in an embodiment of the present application is shown;

[0021] Figure 6 A schematic diagram of a top view of a magnetic shielding side wall in another magnetic memory structure provided in an embodiment of the present application is shown;

[0022] Figure 7 A schematic diagram of a top view of a magnetic shielding side wall in another magnetic memory structure provided in an embodiment of the present application is shown;

[0023] Figure 8 A schematic flow chart of a method for preparing a magnetic memory provided in an embodiment of the present application is shown;

[0024] Fig. 9 A schematic cross-sectional structure diagram of a substrate having a plurality of storage units and a first insulating layer on its surface is shown in a method for preparing a magnetic memory provided in an embodiment of the present application, wherein the first insulating layer covers the storage units;

[0025] Fig.10 Shows the Fig. 9 The schematic diagram of the cross-sectional structure of the substrate after the first insulating layer is etched to form a magnetic tunnel junction gap;

[0026] Fig.11 Shown in Fig.10 A schematic diagram of the cross-sectional structure of the substrate after magnetic shielding material is deposited on the substrate to form a magnetic shielding structure;

[0027] Fig.12 Shown in Fig.11 A schematic diagram of the cross-sectional structure of the substrate after a bit line is formed on the surface of the magnetic shielding structure shown;

[0028] Fig.13 Shown in Fig.12 The cross-sectional structure diagram of the substrate after a second insulating layer is formed on the surface of the bit line is shown.

[0029] The above drawings include the following reference numerals:

[0030] 10. Bit line; 20. Magnetic shielding structure; 201. Magnetic shielding side wall; 202. Magnetic shielding top layer; 30. Storage cell; 301. Top electrode; 302. Magnetic tunnel junction; 303. Bottom electrode; 40. Magnetic tunnel junction gap; 50. Word line; 60. Second insulating layer; 70. First insulating layer. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] In order to improve the reliability of chips in magnetic field environments, magnetic shielding structures are usually manufactured near magnetic tunnel junctions. The magnetization curves of common magnetic shielding schemes at the microscopic level are quite different from those at the macroscopic level. It is difficult to have both the anti-magnetic properties of perpendicular magnetic fields and in-plane magnetic fields, and they are prone to exhibit magnetic concentration characteristics.

[0035] Therefore, the present application studies the above problems and proposes a magnetic memory, such as Figure 1 As shown, it includes: a bit line 10, a magnetic shielding structure 20 and a plurality of memory cells 30, wherein at least some of the plurality of memory cells 30 are arranged along a first direction X, and each memory cell 30 includes a magnetic tunnel junction 302; at least some of the magnetic shielding structure 20 are located between adjacent memory cells 30 along the first direction X, and the magnetic shielding structure 20 is spaced apart from the adjacent memory cells 30.

[0036] The present application can avoid the occurrence of magnetic concentration characteristics by providing a magnetic shielding structure between each adjacent storage unit; two adjacent storage units can share the magnetic shielding structure located between them, and this shared design can save storage area; and since the above-mentioned magnetic shielding structure is spaced apart from the adjacent storage units, it can prevent the storage unit from contacting the magnetic shielding structure and causing a short circuit, so that the storage unit has anti-magnetic characteristics against in-plane magnetic fields, so that the magnetic storage device can have anti-magnetic properties against both perpendicular magnetic fields and in-plane magnetic fields, thereby improving its anti-magnetic ability and further improving the reliability of the magnetic storage device in a magnetic field environment.

[0037] The magnetic tunnel junction 302 may have various forms according to the application, including but not limited to in-plane MTJ, vertical MTJ, top pinned MTJ, bottom pinned MTJ, double-layer MgO MTJ, single-layer MgO MTJ and polymorphic MTJ. In one embodiment, a fixed layer material, a barrier layer material and a free layer material are sequentially deposited on the bottom electrode 303, and a magnetic tunnel junction 302 including a fixed layer, a barrier layer and a free layer is obtained after etching.

[0038] In some optional embodiments, such as Figure 1 As shown, a plurality of memory cells 30 are sequentially distributed along a first direction X, and each memory cell 30 further includes a top electrode 301 and a bottom electrode 303, the top electrode 301 and the bottom electrode 303 are located on opposite sides of a magnetic tunnel junction 302 along a second direction Y, and the second direction Y is perpendicular to the first direction X. The magnetic shielding structure 20 includes: magnetic shielding side walls 201, which are located on both sides of each memory cell 30 along the first direction X; and a magnetic shielding top layer 202 is located on a side of each top electrode 301 away from the magnetic tunnel junction 302.

[0039] In the above optional embodiment, the above magnetic shielding structure 20 can be a soft magnetic material, such as any one or more of Fe, Ni and FeNi alloy, but is not limited to soft magnetic materials. Technical personnel in this field can reasonably select the material of the magnetic shielding structure according to their actual situation, and this application does not make specific limitations.

[0040] In the above optional implementation, if Figure 1 As shown, the arrangement direction of multiple storage units 30 is set to be a first direction X, and the bottom electrode 303, the magnetic tunnel junction 302 and the top electrode 301 are arranged in sequence along the second direction Y. Each storage unit 30 can have magnetic shielding side walls 201 on both sides along the first direction X. This shared design can save storage area. At the same time, only having magnetic shielding side walls 201 on both sides of the storage unit can make the storage unit 30 have anti-magnetic properties against in-plane magnetic fields, thereby making the magnetic memory have anti-magnetic properties of perpendicular magnetic fields and in-plane magnetic fields, improving its anti-magnetic ability, and thereby improving the reliability of the magnetic memory in a magnetic field environment; the above-mentioned magnetic shielding side walls 201 are arranged in contact with the magnetic shielding top layer 202 located on the side of each top electrode 301 away from the magnetic tunnel junction 302.

[0041] In the above optional implementation manner, the material of the top electrode 301 and the bottom electrode 303 may be any one or more of Ta, TaN and TiN, which is not specifically limited in the present application.

[0042] In some optional embodiments, such as Figures 2 to 4 As shown, the magnetic shielding side wall 201 has a first surface close to the top electrode 301 and a second surface close to the bottom electrode 303, the first surface and the second surface are opposite surfaces of the magnetic shielding side wall 201, and the magnetic shielding top layer 202 has a third surface and a fourth surface relative to each other, the third surface is located on the side of the fourth surface away from the storage unit 30, wherein: the maximum vertical distance between the first surface and the magnetic tunnel junction 302 is H1, the maximum vertical distance between the third surface and the magnetic tunnel junction 302 is H2, H1<H2, as shown in FIG. Figure 2 As shown; or the first surface and the third surface are coplanar, as Figure 3or the minimum vertical distance between the first surface and the magnetic tunnel junction 302 is H1, the minimum vertical distance between the third surface and the magnetic tunnel junction 302 is H2, H1>H2, such as Figure 4 shown.

[0043] In the above optional embodiment, the magnetic shielding side wall 201 has a first surface and a second surface, wherein the first surface and the second surface are opposite surfaces of the magnetic shielding side wall 201, and the magnetic shielding top layer 202 has an opposite third surface and a fourth surface. Figure 2 As shown, when the maximum vertical distance between the first surface and the magnetic tunnel junction 302 is H1, the maximum vertical distance between the third surface and the magnetic tunnel junction 302 is H2, and H1<H2, the structural morphology of the magnetic shielding top layer 202 is convex relative to the structural morphology of the magnetic shielding side wall 201; Figure 3 As shown, when the first surface and the third surface are coplanar, the structure and morphology of the magnetic shielding top layer 202 are flat; Figure 4 As shown, when the minimum vertical distance between the first surface and the magnetic tunnel junction 302 is H1, the minimum vertical distance between the third surface and the magnetic tunnel junction 302 is H2, and H1>H2, the structural morphology of the magnetic shielding top layer 202 is concave relative to the structural morphology of the magnetic shielding side wall 201.

[0044] In some optional embodiments, such as Figures 5 to 7 As shown, the magnetic memory further includes a bit line 10 extending along a first direction X, and the bit line 10 is located on a side of the plurality of magnetic shielding top layers 202 away from the memory cell 30. The magnetic shielding side wall 201 has a first projection on the bit line 10, wherein Figure 5 As shown, the first projection of the magnetic shielding side wall 201 may be a rectangle, but is not limited to the above shape. Figure 6 As shown, the first projection of the magnetic shielding side wall 201 can also be a closed figure formed by connecting two symmetrical curves end to end, or a quadrilateral formed by alternately connecting two first side lines and two second side lines, wherein the first side line is a curve protruding toward the inside of the quadrilateral, and the second side line is a straight line. The first side lines of the same quadrilateral are distributed along the first direction X, such as Figure 7 shown.

[0045] It should be noted that the bit line may also include a partial magnetic shielding structure. For example, when the structural morphology of the magnetic shielding top layer is convex relative to the structural morphology of the magnetic shielding side wall, the bit line also includes the convex portion of the magnetic shielding top layer.

[0046] In some optional embodiments, such as Figure 3As shown, the vertical distance between the second surface and the top electrode 301 is H3, the bottom electrode 303 has a fifth surface close to the magnetic tunnel junction 302, and the vertical distance between the fifth surface and the top electrode 301 is H4, H3≥H4.

[0047] In the above optional embodiment, the vertical distance between the second surface of the above-mentioned magnetic shielding side wall 201 close to the bottom electrode 303 and the top electrode 301 is not less than the vertical distance between the above-mentioned fifth surface and the above-mentioned top electrode 301, so that the penetration depth of the magnetic shielding side wall 201 should reach the bottom electrode 303 at least. In other words, the penetration depth of the magnetic shielding side wall 201 should at least be coplanar with the fifth surface of the bottom electrode 303.

[0048] In some optional embodiments, such as Figure 1 As shown, the magnetic memory further includes a word line 50 , which is located at a side of each memory cell 30 away from the bit line 10 , and the word line 50 extends along a third direction Z, which is perpendicular to the second direction Y.

[0049] In the above optional embodiment, the extension direction of the above word line 50 is perpendicular to the direction in which the above top electrode 301, the magnetic tunnel junction 302 and the bottom electrode 303 are arranged in sequence. The above word line 50 is used to prevent the above bit line 10 from reading and writing the capacitor in the magnetic memory, and plays a certain control role on the bit line 10.

[0050] In some optional implementations, the memory cell further includes a barrier layer, and the barrier layer is located on a side of each top electrode 301 away from the magnetic tunnel junction 302 .

[0051] In the above optional embodiment, the above blocking layer can be used to prevent or limit the transmission of charges from the above bit line 10 to the word line 50. The above blocking layer material can be any one or more of silicon oxide and silicon nitride, etc., and this application does not make specific limitations.

[0052] Exemplarily, the structure of the magnetic memory in the present application includes: Figure 1 As shown, a plurality of memory cells 30 are sequentially distributed along a first direction X, a magnetic shielding structure 20 at least partially located between adjacent memory cells 30, a bit line 10 extending along the first direction X and located on a side of a plurality of magnetic shielding top layers 202 away from the memory cells 30, a word line 50 extending along a third direction Z and located on a side of each memory cell 30 away from the bit line 10, and a barrier layer located on a side of each top electrode 301 away from the magnetic tunnel junction 302. Each memory cell 30 includes a magnetic tunnel junction 302, a top electrode 301 and a bottom electrode 303 located on two opposite sides of the magnetic tunnel junction 302 along a second direction Y; and the magnetic shielding structure 20 includes: magnetic shielding sidewalls 201 located on two sides of each memory cell 30 along the first direction X, and a magnetic shielding top layer 202 located on a side of each top electrode 301 away from the magnetic tunnel junction 302.

[0053] It should be noted that the magnetic memory of the present application is not limited to only one row of memory cells 30, but can also be a plurality of memory cells 30 arranged and distributed in an array form. In this case, the magnetic shielding side wall 201 located between adjacent memory cells 30 is arranged between adjacent magnetic tunnel junctions 302 distributed along the first direction X. The magnetic shielding side wall 201 is spaced apart from the adjacent memory cells 30, and there is a first insulating layer 70 between them, which can prevent the memory cells 30 from contacting the magnetic shielding structure 20 and causing a short circuit; there is a magnetic shielding structure 20 between adjacent memory cells 30 in each row.

[0054] According to another embodiment of the present application, a method for preparing a magnetic memory is also provided, comprising the following steps: Figure 8 As shown:

[0055] S1. providing a substrate having a plurality of memory cells on the substrate, at least some of the memory cells being arranged along a first direction, and each memory cell comprising a magnetic tunnel junction;

[0056] S2. Form a magnetic shielding structure on the substrate so that at least a portion of the magnetic shielding structure is located between adjacent storage cells along the first direction, and the magnetic shielding structure is spaced apart from the adjacent storage cells.

[0057] The manufacturing method of the magnetic memory of the present application can solve the problem that it is difficult to have both the antimagnetic properties of the perpendicular magnetic field and the in-plane magnetic field in the related art, and that more storage area is occupied. The two adjacent storage units can share the magnetic shielding structure located between them by setting them, and this shared design can save storage area. There is a magnetic shielding structure between adjacent storage units, and by spacing the magnetic shielding structure from the adjacent storage units, the storage unit can be prevented from contacting the magnetic shielding structure and causing a short circuit, so that the storage unit can have antimagnetic properties against the in-plane magnetic field, and then the magnetic memory can have both the antimagnetic properties of the perpendicular magnetic field and the in-plane magnetic field, improve its antimagnetic ability, and then improve the reliability of the magnetic memory in a magnetic field environment.

[0058] The exemplary embodiments of the method for preparing the magnetic memory provided by the present application will be described in more detail below. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0059] First, Fig. 9As shown, the above step S1 is performed: providing a substrate, on which a plurality of memory cells 30 are provided, at least part of the memory cells 30 are arranged along a first direction X, and each memory cell 30 includes a magnetic tunnel junction 302 .

[0060] In some optional embodiments of the present application, a bottom electrode 303 , a magnetic tunnel junction 302 , and a top electrode 301 are formed in contact with each other in sequence along the second direction Y on the substrate.

[0061] Those skilled in the art can reasonably select the materials of each layer according to the type of magnetic tunnel junction 302 (MTJ) actually required. The above-mentioned magnetic tunnel junction 302 can have various forms according to the application, including but not limited to in-plane MTJ, vertical MTJ, top pinned MTJ, bottom pinned MTJ, double-layer MgO MTJ, single-layer MgO MTJ and polymorphic MTJ. In one embodiment, a fixed layer material, a barrier layer material and a free layer material are sequentially deposited on the bottom electrode 303, and a magnetic tunnel junction 302 including a fixed layer, a barrier layer and a free layer is obtained after etching.

[0062] The bottom electrode 303 can be made by conventional deposition process, and its surface is polished to make it flat. The bottom electrode 303 can be made of Ta, TaN, TiN and other materials, which are not specifically limited in this application.

[0063] The steps of forming the above-mentioned magnetic tunnel junction 302 may include: after the step of forming the bottom electrode 303, sequentially sputtering the film layer materials in the magnetic tunnel junction on the flat surface of the bottom electrode 303, and then depositing a mask layer on the surface of the multilayer film away from the bottom electrode 303, using photolithography and etching technology to remove the mask layer outside the graphic position of the magnetic tunnel junction 302, and finally using an ion beam to etch the magnetic metal multilayer film. The part of the magnetic film not protected by the mask layer will be etched away, leaving the magnetic metal film under the mask layer to form the magnetic tunnel junction 302.

[0064] In a preferred embodiment, the step of forming the above-mentioned top electrode 301 includes: depositing a mask material layer on the top electrode material layer, covering the mask material layer with a photoresist, patterning the photoresist through a photolithography and development process, and etching the mask material layer with the photoresist as a mask to obtain a hard mask layer having a pattern consistent with the photoresist; then etching the top electrode material layer through the hard mask layer to transfer the pattern of the patterned photoresist to obtain the top electrode 301.

[0065] In the above preferred implementation, those skilled in the art can reasonably select the material of the top electrode 301 and the mask material according to the prior art. For example, the material of the top electrode 301 can be Ta, TaN, TiN and the like, and the mask material can be SiO x , SiNx Materials such as the like; those skilled in the art can also reasonably set the process conditions of the above-mentioned photolithography process according to the prior art, which will not be repeated here.

[0066] The material of the substrate may be any one or more of SiC, Si, GaN and diamond. Those skilled in the art may reasonably select the substrate material according to actual conditions.

[0067] After obtaining a substrate having a plurality of memory cells 30 in step S1, Figure 10 to Figure 11 As shown, the above step S2 is performed: forming a magnetic shielding structure 20 on the substrate so that at least a portion of the magnetic shielding structure 20 is located between adjacent storage cells 30 along the first direction, and the magnetic shielding structure 20 is spaced apart from the adjacent storage cells 30 .

[0068] In some optional embodiments of the present application, a ferromagnetic material is covered on the substrate having the plurality of storage cells 30 to form a magnetic shielding structure 20 that is at least partially located between adjacent storage cells 30 .

[0069] In some optional embodiments, before the step of forming the magnetic shielding structure 20 on the substrate, the preparation method further includes: Fig. 9 As shown, a first insulating layer 70 covering the memory cells 30 is formed on the substrate so that a portion of the first insulating layer 70 is filled between adjacent memory cells 30; Fig.10 As shown, the first insulating layer 70 is etched to remove the first insulating layer 70 located on the storage unit 30, and a groove is formed between adjacent storage units 30. In the step of forming the magnetic shielding structure 20, as shown in FIG. Fig.11 As shown, a soft magnetic material is deposited on the substrate so that part of the soft magnetic material fills the groove to form a magnetic shielding side wall 201 , and the remaining soft magnetic material is located on the storage unit 30 to form a magnetic shielding top layer 202 .

[0070] The deposition process in the step of covering the first insulating layer may be a deposition process such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Those skilled in the art may reasonably select the process for covering the first insulating layer according to specific circumstances.

[0071] The above-mentioned step of etching the first insulating layer may include: coating a photoresist on the first insulating layer, selecting the position of the magnetic tunnel junction gap 40 using a mask plate, irradiating the exposed area with ultraviolet light to cause a chemical reaction, and then dissolving and removing the photoresist corresponding to the exposed area by development technology, using the remaining photoresist as a mask layer, and then using dry etching to form the magnetic tunnel junction gap 40.

[0072] Specifically, after obtaining a substrate having a plurality of memory cells 30 by executing step S1, a first insulating layer 70 can be deposited on the substrate so that it completely covers the plurality of memory cells 30 and partially fills the space between each adjacent memory cell 30 to prevent the memory cell 30 from contacting the magnetic shielding side wall 201 and causing a short circuit; the first insulating layer 70 located on the surface of the top electrode 301 of the memory cell 30 and between the adjacent memory cells 30 is then etched to form a magnetic tunnel junction gap 40, so that in the step of forming the magnetic shielding structure 20, soft magnetic material is deposited on the surface of the plurality of the above-mentioned top electrodes 301, so that part of the soft magnetic material fills the magnetic tunnel junction gap 40 to form the magnetic shielding side wall 201, and the remaining soft magnetic material is located on the surface of the memory cell 30 to form a magnetic shielding top layer 202.

[0073] The deposition process in the above-mentioned step of depositing the soft magnetic material can be a deposition process such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Those skilled in the art can reasonably select the process for depositing the soft magnetic material according to the specific situation.

[0074] In some optional embodiments of the present application, the projection size of the top electrode 301 on the substrate is set to be larger than the projection size of the magnetic tunnel junction 302 on the substrate. This not only allows the first insulating layer 70 near the magnetic tunnel junction 302 to be retained during the etching process to block the magnetic tunnel junction 302 and the magnetic shielding structure 20 and reduce the risk of short circuits, but also allows the channel between the etched adjacent storage cells 30 to be deepened, thereby manufacturing the magnetic shielding sidewall 201 with a higher sidewall, thereby enhancing the vertical magnetic field anti-magnetic properties of the magnetic shielding structure 20.

[0075] The etching process of the magnetic tunnel junction gap 40 can be dry etching or wet etching, which is not specifically limited in this application. Specifically, the etching process can be performed by coating a photoresist on the first insulating layer, selecting the position of the magnetic tunnel junction gap 40 using a mask plate, irradiating the exposed area with ultraviolet light to cause a chemical reaction, and then dissolving and removing the photoresist corresponding to the exposed area by a developing technology, using the remaining photoresist as a mask layer, and then using dry etching to form the magnetic tunnel junction gap 40.

[0076] The above-mentioned soft magnetic material can be any one or more of Fe, Ni and FeNi alloy, but is not limited to the above-mentioned types. Those skilled in the art can reasonably select the soft magnetic material according to actual conditions, and this application does not make specific limitations.

[0077] After obtaining the magnetic shielding structure 20 in the above step S2, the above preparation method in the present application may further include: covering the surface of the magnetic shielding structure 20 with a non-magnetic metal layer; flattening the non-magnetic metal layer to form a bit line 10, such as Fig.12It should be noted that the planarization process may be chemical mechanical polishing (CMP), but is not limited to the above method.

[0078] In some optional embodiments of the present application, a non-magnetic metal layer is deposited on the surface of the magnetic shielding top layer 202 of the magnetic shielding structure 20, and then planarized to form the bit line 10. The non-magnetic metal material may be any one or more of copper, aluminum, and magnesium, and those skilled in the art may reasonably select the non-magnetic metal material according to actual conditions, and the present application does not make any specific limitation.

[0079] In some optional embodiments, the deposition process in the above-mentioned step of depositing the non-magnetic metal is a deposition process such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), and technical personnel in this field can reasonably select the process for depositing the non-magnetic metal according to the specific circumstances.

[0080] In some optional implementations, an insulating material is deposited on the surface of the bit line 10 and planarized to form a second insulating layer 60, such as Fig.13 shown.

[0081] The deposition process in the step of depositing the second insulating layer is a deposition process such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Those skilled in the art can reasonably select the process for depositing the second insulating layer according to the specific situation. The insulating material can be SiO2, but is not limited to the above types, and this application does not make specific limitations.

[0082] Exemplarily, the method for preparing the magnetic memory in the present application includes the following steps:

[0083] A substrate is provided, on which a plurality of memory cells 30 are provided, each memory cell 30 including a magnetic tunnel junction 302; a first insulating layer 70 covering the memory cells 30 is formed on the substrate, so that a portion of the first insulating layer 70 is filled between adjacent memory cells 30, such as Fig. 9 As shown;

[0084] The first insulating layer 70 is etched to remove the first insulating layer 70 located on the memory cell 30, and to form a magnetic tunnel junction gap 40 between adjacent memory cells 30. Fig.10 As shown;

[0085] Soft magnetic material is deposited on the surface of the plurality of top electrodes 301, so that part of the soft magnetic material fills the magnetic tunnel junction gap 40 to form a magnetic shielding sidewall 201, and the remaining soft magnetic material is located on the surface of the storage unit 30 to form a magnetic shielding top layer 202. Fig.11 As shown;

[0086] A non-magnetic metal layer is covered on the surface of the magnetic shielding structure 20; the non-magnetic metal layer is planarized to form a bit line 10, such as Fig.12 As shown;

[0087] An insulating material is deposited on the surface of the bit line 10 and planarized to form a second insulating layer 60. Fig.13 shown.

[0088] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0089] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A magnetic memory, characterized in that: include: A plurality of memory cells, at least some of which are arranged along a first direction, and each of which comprises a magnetic tunnel junction; A magnetic shielding structure, at least a portion of which is located between the adjacent storage units along the first direction, and the magnetic shielding structure is spaced apart from the adjacent storage units.

2. The magnetic memory according to claim 1, characterized in that: Each of the memory cells further includes a top electrode and a bottom electrode, the top electrode and the bottom electrode are located on opposite sides of the magnetic tunnel junction along a second direction, the second direction is perpendicular to the first direction, and the magnetic shielding structure includes: Magnetic shielding side walls, located on both sides of each storage unit along the first direction; A magnetic shielding top layer is located on a side of each of the top electrodes away from the magnetic tunnel junction.

3. The magnetic memory according to claim 2, characterized in that: The magnetic shielding sidewall has a first surface close to the top electrode and a second surface close to the bottom electrode, the first surface and the second surface are opposite surfaces of the magnetic shielding sidewall, the magnetic shielding top layer has an opposite third surface and a fourth surface, the third surface is located on a side of the fourth surface away from the storage unit, wherein: The maximum vertical distance between the first surface and the magnetic tunnel junction is H1, the maximum vertical distance between the third surface and the magnetic tunnel junction is H2, H1<H2; or The first surface is coplanar with the third surface; or The minimum vertical distance between the first surface and the magnetic tunnel junction is H1, and the minimum vertical distance between the third surface and the magnetic tunnel junction is H2, where H1>H2.

4. The magnetic memory according to claim 2, characterized in that: The magnetic memory further comprises a bit line extending along the first direction, the bit line is located on a side of the plurality of magnetic shielding top layers away from the memory cell, and the magnetic shielding side wall has a first projection on the bit line, wherein: The first projection is a rectangle; or The first projection is a closed figure formed by connecting two symmetrical curves end to end; or The first projection is a quadrilateral formed by alternately connecting two first side lines and two second side lines, the first side lines are curves protruding toward the inside of the quadrilateral, the second side lines are straight lines, and the first side lines of the same quadrilateral are distributed along the first direction.

5. The magnetic memory according to claim 3, characterized in that: The vertical distance between the second surface and the top electrode is H3, the bottom electrode has a fifth surface close to the magnetic tunnel junction, the vertical distance between the fifth surface and the top electrode is H4, and H3≥H4.

6. The magnetic memory according to claim 4, characterized in that: The magnetic memory further comprises: The word line is located at a side of each of the memory cells away from the bit line, and the word line extends along a third direction, which is perpendicular to the second direction.

7. The magnetic memory according to any one of claims 1 to 5, characterized in that: The storage unit also includes: A barrier layer is located on a side of each of the top electrodes away from the magnetic tunnel junction.

8. A method for preparing a magnetic memory according to any one of claims 1 to 7, characterized in that: The following steps are involved: Providing a substrate, wherein a plurality of memory cells are provided on the substrate, at least some of the memory cells are arranged along a first direction, and each of the memory cells includes a magnetic tunnel junction; A magnetic shielding structure is formed on the substrate, so that at least a portion of the magnetic shielding structure is located between the adjacent storage units along the first direction, and the magnetic shielding structure is spaced apart from the adjacent storage units.

9. The preparation method according to claim 8, characterized in that: Before the step of forming the magnetic shielding structure on the substrate, the preparation method further comprises: forming a first insulating layer covering the memory cells on the substrate so that a portion of the first insulating layer is filled between adjacent memory cells; The first insulating layer is etched to remove the first insulating layer on the memory cells and to form grooves between adjacent memory cells. In the step of forming the magnetic shielding structure, soft magnetic material is deposited on the substrate so that part of the soft magnetic material fills the groove to form a magnetic shielding side wall, and the remaining soft magnetic material is located on the storage unit to form a magnetic shielding top layer.

10. The preparation method according to claim 8, characterized in that: The preparation method further comprises: Covering a non-magnetic metal layer on the surface of the magnetic shielding structure; The non-magnetic metal layer is planarized to form a bit line.

Images