A flexible magnetic memory and its preparation method

Abstract

The present invention discloses a flexible magnetic memory and a preparation method thereof, which relate to the field of electronics, and a composite flexible substrate layer, wherein the composite substrate layer comprises, from bottom to top, a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer, and a second silicon oxide layer. It can be seen that by replacing the flexible substrate layer in the prior art with a composite flexible substrate layer having a greater thickness and better sealing, the reliability of the flexible substrate layer can be enhanced, thereby improving the reliability of the flexible magnetic memory device. Thus, on the one hand, because the introduced composite flexible substrate layer is a laminated structure, its stress resistance is greater, thereby improving the stress resistance of the flexible magnetic memory device. On the other hand, because the introduction of a structural layer with better sealing makes the composite flexible substrate layer more resistant to water and oxygen corrosion, thereby improving the reliability of the flexible magnetic memory device.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electronics, and in particular to a flexible magnetic memory and a preparation method thereof. Background Art

[0002] With the continuous development and maturity of emerging memory R&D processes, spin-orbit torque magnetic memory (SOT-MRAM) has been increasingly widely used. Among them, flexible SOT-MRAM, as a new generation of magnetic memory devices, has also been increasingly widely used. Compared with conventional SOT-MRAM, flexible SOT-MRAM has a flexible substrate layer under the heavy metal layer to support the heavy metal layer and the magnetic tunnel junction (MTJ) arranged on the heavy metal layer.

[0003] Typically, the flexible substrate layer is made of polyimide (PI). However, the structural design of the flexible SOT-MRAM is too thin. This makes the flexible SOT-MRAM with this structure extremely susceptible to water and oxygen corrosion in some high-integration and high-storage performance application scenarios, causing reliability issues for the flexible SOT-MRAM device and affecting the device's service life. Summary of the Invention

[0004] Embodiments of the present invention provide a flexible magnetic memory and a method for preparing the same, which can reduce the susceptibility of flexible SOT-MRAM to water and oxygen corrosion in some scenarios requiring high integration and high storage performance, thereby reducing reliability issues for flexible SOT-MRAM devices.

[0005] In order to solve the above problems, the first aspect of the present invention provides a flexible magnetic memory comprising:

[0006] A composite flexible substrate layer and a magnetic tunnel junction array arranged on the composite flexible substrate layer. The composite substrate layer comprises from bottom to top: a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer and a second silicon oxide layer.

[0007] In some embodiments, a first placement area, a second placement area, and a bending area are provided above the second silicon oxide layer, and the bending area is provided between the first placement area and the second placement area to enable the flexible magnetic memory device to bend;

[0008] The first placement area is used to place a first magnetic tunnel junction array;

[0009] The second placement area is used to place the second magnetic tunnel junction array. In this way, by arranging the magnetic tunnel junction placement areas on both sides of the bending area, when the composite flexible substrate layer is bent, the space occupancy rate can be reduced without affecting the performance of the flexible magnetic memory.

[0010] In some embodiments, the flexible magnetic memory further comprises: a filling region disposed within the composite substrate layer corresponding to the bending region, the filling region having a filling depth extending from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer, the filling region being filled with a colloidal substance for enhancing the bending resistance of the bending region when the flexible magnetic memory is in a bent state. In this manner, the bending resistance of the bending region when the flexible magnetic memory is in a bent state can be enhanced. In some embodiments, a metal wire layer and a colloidal layer disposed above the metal wire layer are further disposed above the filling region, the metal wire layer and the colloidal layer being configured to enhance the bending resistance of the bending region when the flexible magnetic memory is in a bent state. In this manner, the ability of the bending region to extend when the flexible magnetic memory is in a bent state can be enhanced, further enhancing the bending resistance of the flexible magnetic memory when in a bent state.

[0011] In some embodiments, the first magnetic tunnel junction array and the second magnetic tunnel junction array each include at least one magnetic tunnel junction with a light-sensitive magnetic free layer. Thus, an external light field can be used to induce a resistance state flip in the flexible magnetic memory, thereby reducing the flip current of the flexible magnetic memory.

[0012] In some embodiments, the flexible magnetic memory further includes a light field generator disposed beneath the first transparent polyimide layer. The light field generator is configured to induce a resistance state flip in the magnetic tunnel junction with the photosensitive magnetic free layer. This reduces the flipping current of the flexible magnetic memory.

[0013] In a second aspect of the present application, a method for preparing a flexible magnetic memory is also provided.

[0014] Applicable to a flexible magnetic memory, the flexible magnetic memory comprising: a composite flexible substrate layer and a magnetic tunnel junction array arranged on the composite flexible substrate layer, the method comprising:

[0015] constructing a first transparent polyimide layer;

[0016] constructing a first silicon oxide layer on the first transparent polyimide layer;

[0017] constructing a second transparent polyimide layer on the first silicon oxide layer;

[0018] constructing a silicon nitride layer on the second transparent polyimide layer;

[0019] constructing a second silicon oxide layer on the silicon nitride layer;

[0020] At least one magnetic tunnel junction array is arranged in a preset area on the upper surface of the second silicon oxide layer.

[0021] In some embodiments, after constructing the second silicon oxide layer on the silicon nitride layer and before providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer, the method further includes:

[0022] A first placement area, a second placement area, and a folding area are provided on the upper surface of the second silicon oxide layer, wherein the bending area is provided between the first placement area and the second placement area, and is used to achieve bending during the flexible magnetic storage period;

[0023] The first placement area is used to place a first magnetic tunnel junction array;

[0024] The second placement area is used to place the second magnetic tunnel junction array. In this way, by arranging the magnetic tunnel junction placement areas on both sides of the bending area, when the composite flexible substrate layer is bent, the space occupancy rate can be reduced without affecting the performance of the flexible magnetic memory.

[0025] Optionally, the preset area includes: a first placement area and a second placement area.

[0026] In some embodiments, the method further comprises:

[0027] Over-etching the bending region to obtain a filling region, wherein the depth of the filling region is from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer;

[0028] Filling the filling area with a colloidal substance, wherein the filling height of the colloidal substance is higher than or equal to the upper surface of the second silicon oxide layer;

[0029] constructing a metal wire layer on the upper surface of the colloidal substance;

[0030] A colloid layer is constructed on the upper surface of the metal wire layer, so as to improve the anti-bending ability of the bending area when the flexible magnetic memory is in a bent state.

[0031] Optionally, the filling of the filling area with a colloidal substance, before constructing the metal wire layer on the upper surface of the colloidal substance, further includes: quenching the colloidal substance to form a film stack structure.

[0032] In some embodiments, providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer includes:

[0033] At least one magnetic tunnel junction with a light-sensitive magnetic free layer is constructed in the first placement area and the second placement area. In this way, the flexible magnetic memory can be induced to undergo a resistance state reversal under the action of an external light field, thereby reducing the reversal current of the flexible magnetic memory.

[0034] In some embodiments, the flexible magnetic tunnel junction preparation process further includes the following two processes: photolithography and etching.

[0035] An embodiment of the present invention provides a flexible magnetic memory and a method for preparing the same. The magnetic memory includes a composite flexible substrate layer, which comprises, from bottom to top, a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer, and a second silicon oxide layer. It can be seen that by replacing the flexible substrate layer in the prior art with a composite flexible substrate layer having a greater thickness and better sealing, the reliability of the flexible substrate layer can be enhanced, thereby improving the reliability of the flexible magnetic memory device. Thus, on the one hand, because the introduced composite flexible substrate layer has a laminated structure, its stress resistance is greater, thereby improving the stress resistance of the flexible magnetic memory device. On the other hand, because the introduction of a structural layer with better sealing makes the composite flexible substrate layer more resistant to water and oxygen corrosion, thereby improving the reliability of the flexible magnetic memory device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application.

[0037] Figure 1 Schematic diagram of the structure of a flexible magnetic memory according to one embodiment of the present application;

[0038] Figure 2 Schematic diagram of the bending area and placement area structure according to one embodiment of the present application;

[0039] Figure 3 Schematic diagram of a flexible magnetic memory device in a bent state according to an embodiment of the present application;

[0040] Figure 4 Schematic diagram of the structure of the filling area of ​​the composite flexible substrate layer according to one embodiment of the present application;

[0041] Figure 5 Schematic diagram of a process for preparing a flexible magnetic memory according to one embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described implementation methods are only part of the embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0043] Those skilled in the art will understand that the terms "first" and "second" in this application are only used to distinguish different devices, modules or parameters, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0044] An embodiment of the present invention provides a flexible magnetic memory and a method for preparing the same. The magnetic memory includes a composite flexible substrate layer, which comprises, from bottom to top, a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer, and a second silicon oxide layer. It can be seen that by replacing the flexible substrate layer in the prior art with a composite flexible substrate layer having a greater thickness and better sealing, the reliability of the flexible substrate layer can be enhanced, thereby improving the reliability of the flexible magnetic memory device. Thus, on the one hand, the greater thickness of the introduced composite flexible substrate layer increases its stress resistance, thereby improving the stress resistance of the flexible magnetic memory device. On the other hand, the introduction of a structural layer with better sealing makes the composite flexible substrate layer more resistant to water and oxygen corrosion, thereby improving the reliability of the flexible magnetic memory device.

[0045] With the continuous development and maturity of emerging memory R&D processes, spin-orbit torque magnetic memory (SOT-MRAM) has been increasingly widely used. Among them, flexible SOT-MRAM, as a new generation of magnetic memory devices, has also been increasingly widely used. Compared with conventional SOT-MRAM, flexible SOT-MRAM has a flexible substrate layer under the heavy metal layer to support the heavy metal layer and the magnetic tunnel junction (MTJ) arranged on the heavy metal layer.

[0046] Typically, the flexible substrate layer is made of polyimide (PI). However, the structural design of the flexible SOT-MRAM is too thin. This makes the flexible SOT-MRAM with this structure extremely susceptible to water and oxygen corrosion in some high-integration and high-storage performance application scenarios, causing reliability issues for the flexible SOT-MRAM device and affecting the device's service life.

[0047] In one embodiment of the present application, in order to reduce the reliability issues caused by flexible SOT-MRAM devices due to their susceptibility to water and oxygen corrosion in some scenarios requiring high integration and high storage performance, the flexible SOT-MRAM devices are greatly reduced.

[0048] like Figure 1 The schematic diagram of the flexible magnetic memory structure shown in FIG.

[0049] The magnetic memory comprises:

[0050] A composite flexible substrate layer and a magnetic tunnel junction array arranged on the composite flexible substrate layer. The composite substrate layer comprises from bottom to top: a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer and a second silicon oxide layer.

[0051] Optionally, the magnetic memory further includes a magnetic tunnel junction arranged on the composite flexible substrate layer.

[0052] In one embodiment of the present application, Figure 2 As shown, a first placement area, a second placement area and a bending area are provided above the second silicon oxide layer, and the bending area is provided between the first placement area and the second placement area, for realizing bending of the flexible magnetic memory device;

[0053] The first placement area is used to place a first magnetic tunnel junction array;

[0054] The second placement area is used to place a second magnetic tunnel junction array.

[0055] It is understood that the arrangement principle of the first placement area, the second placement area and the bending area includes: after the composite flexible substrate layer of the flexible magnetic memory is bent, the first placement area and the second placement area are respectively located on both sides of the bending area. In this way, when the performance of the flexible magnetic memory needs to be unaffected, the space occupancy rate can be reduced by bending the composite flexible substrate layer, as shown in FIG. Figure 3 shown.

[0056] Optionally, the number of placement areas corresponding to each side of the bending area is greater than or equal to one.

[0057] In one possible implementation, Figure 4 As shown, the flexible magnetic memory structure can also be: a filling area is set inside the composite substrate layer corresponding to the bending area, the filling depth of the filling area is from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer, and the filling area is filled with a colloidal substance to enhance the bending resistance of the bending area when the flexible magnetic memory is in a bent state.

[0058] Optionally, a colloidal substance is filled in the filling area, and the filling height of the colloidal substance is not lower than the upper surface of the second silicon oxide layer.

[0059] Optionally, the colloidal filling material includes: PLN organic glue.

[0060] Optionally, a metal wire layer and a colloid layer are provided above the filling area, and the metal wire layer and the colloid layer are used to improve the anti-bending ability of the bending area when the flexible magnetic memory is in a bent state.

[0061] Optionally, if the filling height of the colloid substance is higher than the upper surface of the second silicon oxide layer, the metal wire layer and the colloid layer are disposed on the colloid filling substance.

[0062] In a possible implementation, the first magnetic tunnel junction array and the second magnetic tunnel junction array each include at least one magnetic tunnel junction with a photosensitive magnetic free layer.

[0063] Optionally, the flexible magnetic memory further includes a light field generator disposed beneath the first transparent polyimide layer, the light field generator configured to induce a resistance state flip in the magnetic tunnel junction with the photosensitive magnetic free layer. It is understood that the light field generator can be a light source that emits a light field according to predetermined requirements.

[0064] It is understandable that, because the composite flexible substrate layer is made of materials with good light transmittance, such as the first transparent polyimide layer and the second transparent polyimide layer, providing a corresponding light field generator below the flexible magnetic tunnel junction can reduce the switching current of the magnetic tunnel junction pre-installed with a light-sensitive free layer, thereby inducing resistance state reversal.

[0065] In another embodiment of the present application, a method for preparing a flexible magnetic memory is also introduced.

[0066] Applicable to flexible magnetic memory, the flexible magnetic memory includes: a composite flexible substrate layer, the method includes: Figure 5 As shown,

[0067] The method comprises:

[0068] constructing a first transparent polyimide layer;

[0069] constructing a first silicon oxide layer on the first transparent polyimide layer;

[0070] constructing a second transparent polyimide layer on the first silicon oxide layer;

[0071] constructing a silicon nitride layer on the second transparent polyimide layer;

[0072] constructing a second silicon oxide layer on the silicon nitride layer;

[0073] At least one magnetic tunnel junction array is arranged in a preset area on the upper surface of the second silicon oxide layer.

[0074] In one possible implementation, after constructing the second silicon oxide layer on the silicon nitride layer and before providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer, the method further includes:

[0075] A first placement area, a second placement area, and a folding area are provided on the upper surface of the second silicon oxide layer, wherein the bending area is provided between the first placement area and the second placement area, and is used to achieve bending during the flexible magnetic storage period;

[0076] The first placement area is used to place a first magnetic tunnel junction array;

[0077] The second placement area is used to place a second magnetic tunnel junction array.

[0078] Optionally, the preset area includes a first placement area and a second placement area.

[0079] Optionally, the method further includes:

[0080] Over-etching the bending region to obtain a filling region, wherein the depth of the filling region is from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer;

[0081] Filling the filling area with a colloidal substance, wherein the filling height of the colloidal substance is higher than or equal to the upper surface of the second silicon oxide layer;

[0082] constructing a metal wire layer on the upper surface of the colloidal substance;

[0083] A colloid layer is constructed on the upper surface of the metal wire layer.

[0084] Optionally, the filling of the filling area with a colloidal substance, before constructing the metal wire layer on the upper surface of the colloidal substance, further includes: quenching the colloidal substance to form a film stack structure.

[0085] In one possible implementation, providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer includes:

[0086] At least one magnetic tunnel junction with a photosensitive magnetic free layer is constructed in the first placement area and the second placement area.

[0087] Optionally, the flexible magnetic tunnel junction preparation process further includes the following two processes: photolithography and etching.

[0088] An embodiment of the present invention provides a flexible magnetic memory and a method for preparing the same. The magnetic memory includes a composite flexible substrate layer, which comprises, from bottom to top, a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer, and a second silicon oxide layer. It can be seen that by replacing the flexible substrate layer in the prior art with a composite flexible substrate layer having a greater thickness and better sealing, the reliability of the flexible substrate layer can be enhanced, thereby improving the reliability of the flexible magnetic memory device. Thus, on the one hand, because the introduced composite flexible substrate has a laminated structure, its stress resistance is greater, thereby improving the stress resistance of the flexible magnetic memory device. On the other hand, because the introduction of a structural layer with better sealing makes the composite flexible substrate layer more resistant to water and oxygen corrosion, thereby improving the reliability of the flexible magnetic memory device.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flexible magnetic memory, characterized in that: The magnetic memory comprises: A composite flexible substrate layer and a magnetic tunnel junction array provided on the composite flexible substrate layer, wherein the composite flexible substrate layer comprises, from bottom to top, a first transparent polyimide layer, a first silicon oxide layer, a second transparent polyimide layer, a silicon nitride layer, and a second silicon oxide layer; A first placement area, a second placement area, and a bending area are arranged above the second silicon oxide layer. The bending area is arranged between the first placement area and the second placement area to achieve bending of the flexible magnetic memory.

2. The flexible magnetic memory according to claim 1, wherein The first placement area is used to place a first magnetic tunnel junction array; The second placement area is used to place a second magnetic tunnel junction array.

3. The flexible magnetic memory according to claim 2, wherein: The flexible magnetic memory also includes: a filling area arranged inside the composite flexible substrate layer corresponding to the bending area, the filling depth of the filling area being from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer, and the filling area being filled with a colloidal substance to enhance the bending resistance of the bending area when the flexible magnetic memory is in a bent state.

4. The flexible magnetic memory according to claim 3, wherein: A metal wire layer and a colloid layer are provided above the filling area. The metal wire layer and the colloid layer are used to improve the anti-bending ability of the bending area when the flexible magnetic memory is in a bent state.

5. The flexible magnetic memory according to claim 2, wherein: The first magnetic tunnel junction array and the second magnetic tunnel junction array each include at least one magnetic tunnel junction with a photosensitive magnetic free layer.

6. The flexible magnetic memory according to claim 5, wherein: The flexible magnetic memory further includes a light field generator, which is disposed below the first transparent polyimide layer and is used to induce the magnetic tunnel junction with the photosensitive magnetic free layer to perform resistance state switching.

7. A method for preparing a flexible magnetic memory, characterized in that: Applicable to a flexible magnetic memory, the flexible magnetic memory comprising: a composite flexible substrate layer and a magnetic tunnel junction array arranged on the composite flexible substrate layer, the method comprising: constructing a first transparent polyimide layer; constructing a first silicon oxide layer on the first transparent polyimide layer; constructing a second transparent polyimide layer on the first silicon oxide layer; constructing a silicon nitride layer on the second transparent polyimide layer; constructing a second silicon oxide layer on the silicon nitride layer; A first placement area, a second placement area, and a bending area are provided on the upper surface of the second silicon oxide layer, wherein the bending area is provided between the first placement area and the second placement area, so as to realize bending of the flexible magnetic memory; At least one magnetic tunnel junction array is arranged in a preset area on the upper surface of the second silicon oxide layer.

8. The method for preparing a flexible magnetic memory according to claim 7, wherein: After constructing the second silicon oxide layer on the silicon nitride layer and before providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer, the method further includes: The first placement area is used to place a first magnetic tunnel junction array; The second placement area is used to place a second magnetic tunnel junction array.

9. The method for preparing a flexible magnetic memory according to claim 8, wherein: The method further comprises: Over-etching the bending region to obtain a filling region, wherein the depth of the filling region is from the upper surface of the first transparent polyimide layer to the upper surface of the second silicon oxide layer; Filling the filling area with a colloidal substance, wherein the filling height of the colloidal substance is higher than or equal to the upper surface of the second silicon oxide layer; constructing a metal wire layer on the upper surface of the colloidal substance; A colloid layer is constructed on the upper surface of the metal wire layer.

10. The method for preparing a flexible magnetic memory according to claim 7, wherein: The step of providing at least one magnetic tunnel junction array in a preset area on the upper surface of the second silicon oxide layer comprises: At least one magnetic tunnel junction with a photosensitive magnetic free layer is constructed in the first placement area and the second placement area.

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