Magnetic storage device

Abstract

To provide a magnetic memory device capable of accurately forming magnetoresistive elements. [Solution] The magnetic memory device according to the embodiment comprises a magnetoresistive effect element 40 having a structure in which the first magnetic layer, the second magnetic layer and the non-magnetic layer are stacked, including a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a non-magnetic layer provided between the first magnetic layer and the second magnetic layer; an electrode 53 having an upper surface connected to the lower surface of the magnetoresistive effect element; and a first insulating layer 61 made of amphoteric oxide that surrounds the side surface of the electrode and has an upper surface at a lower position than the upper surface of the electrode.

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic storage device.

Background Art

[0002] Magnetic storage devices in which a plurality of magnetoresistive elements are integrated on a semiconductor substrate have been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Provide a magnetic storage device capable of accurately forming a magnetoresistive element.

Means for Solving the Problems

[0005] The magnetic storage device according to the embodiment includes a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a non-magnetic layer provided between the first magnetic layer and the second magnetic layer, and has a structure in which the first magnetic layer, the second magnetic layer, and the non-magnetic layer are laminated. A magnetoresistive element, an electrode having an upper surface connected to the lower surface of the magnetoresistive element, and a first insulating layer formed of an amphoteric oxide that surrounds the side surface of the electrode and has an upper surface at a position lower than the upper surface of the electrode.

Brief Description of the Drawings

[0006] [[ID=CB]] [Figure 1] It is a perspective view schematically showing the basic configuration of the magnetic storage device according to the first embodiment. [Figure 2A] It is a cross-sectional view schematically showing the basic configuration of the magnetic storage device according to the first embodiment. [Figure 2B] This is a schematic cross-sectional view showing the basic configuration of a magnetic storage device according to the first embodiment. [Figure 3A] This is a schematic cross-sectional view showing the configuration of the magnetoresistive element body of the magnetic storage device according to the first embodiment. [Figure 3B] This is a schematic cross-sectional view showing a modified configuration of the magnetoresistive element body of the magnetic storage device according to the first embodiment. [Figure 4] This figure schematically shows the current-voltage characteristics of the selector of the magnetic storage device according to the first embodiment. [Figure 5] This figure schematically shows the relationship between the pattern on the lower surface of the magnetoresistive element and the pattern on the upper surface of the upper electrode of the selector in a magnetic storage device according to the first embodiment. [Figure 6A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 6B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 7A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 7B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 8A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 8B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 9A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 9B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 10A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the first embodiment. [Figure 10B]It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the first embodiment. [Figure 11A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the first embodiment. [Figure 11B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the first embodiment. [Figure 12A] It is a cross-sectional view schematically showing the basic configuration of a magnetic storage device according to the second embodiment. [Figure 12B] It is a cross-sectional view schematically showing the basic configuration of a magnetic storage device according to the second embodiment. [Figure 13A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 13B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 14A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 14B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 15A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 15B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 16A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 16B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 17A] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 17B] It is a cross-sectional view schematically showing a part of a method for manufacturing a magnetic storage device according to the second embodiment. [Figure 18A]This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the second embodiment. [Figure 18B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the second embodiment. [Figure 19A] This is a schematic cross-sectional view showing the basic configuration of a magnetic storage device according to the third embodiment. [Figure 19B] This is a schematic cross-sectional view showing the basic configuration of a magnetic storage device according to the third embodiment. [Figure 20] This figure schematically shows the relationship between the pattern on the lower surface of the magnetoresistive element and the pattern on the upper surface of the wiring in a magnetic storage device according to the third embodiment. [Figure 21A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 21B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 22A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 22B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 23A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 23B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 24A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 24B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 25A] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 25B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 26A]This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Figure 26B] This is a schematic cross-sectional view showing a part of the manufacturing method for a magnetic storage device according to the third embodiment. [Modes for carrying out the invention]

[0007] The embodiments will be described below with reference to the drawings.

[0008] (First embodiment) Figure 1 is a schematic perspective view showing the basic configuration of a magnetic storage device according to the first embodiment.

[0009] The magnetic memory device shown in Figure 1 includes a plurality of wirings 10, each extending in the X direction, a plurality of wirings 20, each extending in the Y direction, and a plurality of memory cells 30 connected between the plurality of wirings 10 and the plurality of wirings 20.

[0010] One of the wires 10 and 20 corresponds to a word line, and the other of the wires 10 and 20 corresponds to a bit line.

[0011] Each memory cell 30 includes a magnetoresistive element 40 and a selector (switching element) 50. The magnetoresistive element 40 and the selector 50 are connected in series between the wiring 10 and the wiring 20 and are stacked in the Z direction. The selector 50 is provided on the lower side of the magnetoresistive element 40.

[0012] Note that the X, Y, and Z directions intersect each other. Specifically, the X, Y, and Z directions are orthogonal to each other.

[0013] Figures 2A and 2B are schematic cross-sectional views illustrating the basic configuration of the magnetic storage device according to this embodiment. Figure 2A is a cross-sectional view parallel to the X direction, and Figure 2B is a cross-sectional view parallel to the Y direction.

[0014] The structures shown in Figures 2A and 2B are provided on a lower region (not shown) including a semiconductor substrate (not shown), and include wiring 10, a memory cell 30 including a magnetoresistive element 40 and a selector (switching element) 50, and an insulating region 60. Although not shown in Figures 2A and 2B, wiring 20 as shown in Figure 1 is usually provided on the upper side of the memory cell 30.

[0015] As already mentioned, the memory cell 30 has a structure in which magnetoresistive elements 40 and selectors 50 are stacked in the Z direction, with the selectors 50 provided on the lower side of the magnetoresistive elements 40.

[0016] The magnetoresistive element 40 includes a lower electrode 42, an upper electrode 43, and a magnetoresistive element body 41 provided between the lower electrode 42 and the upper electrode 43, and has a structure in which the magnetoresistive element body 41, the lower electrode 42, and the upper electrode 43 are stacked in the Z direction.

[0017] Figure 3A is a schematic cross-sectional view showing the configuration of the magnetoresistive element body 41.

[0018] The magnetoresistive element body 41 is an MTJ (magnetic tunnel junction) element and includes a memory layer (first magnetic layer) 41a, a reference layer (second magnetic layer) 41b, and a tunnel barrier layer (non-magnetic layer) 41c, with the memory layer 41a, reference layer 41b, and tunnel barrier layer 41c stacked in the Z direction.

[0019] The memory layer 41a is a ferromagnetic layer having a variable magnetization direction, and is formed of, for example, a CoFeB layer containing cobalt (Co), iron (Fe), and boron (B). A variable magnetization direction means that the magnetization direction changes in response to a predetermined writing current.

[0020] The reference layer 41b is a ferromagnetic layer having a fixed magnetization direction, and includes, for example, a CoFeB layer containing cobalt (Co), iron (Fe), and boron (B), and a superlattice layer of cobalt (Co) and platinum (Pt).

[0021] The tunnel barrier layer 41c is an insulating layer provided between the memory layer 41a and the reference layer 41b, and is formed, for example, from an MgO layer containing magnesium (Mg) and oxygen (O).

[0022] The magnetoresistive element body 41 may further include a shift-canceling layer or the like that cancels the electric field applied to the memory layer 41a from the reference layer 41b.

[0023] When the magnetization direction of the memory layer 41a is parallel to the magnetization direction of the reference layer 41b, the magnetoresistive element body 41 is in a low-resistance state with relatively low resistance. When the magnetization direction of the memory layer 41a is antiparallel to the magnetization direction of the reference layer 41b, the magnetoresistive element body 41 is in a high-resistance state with relatively high resistance. Therefore, the magnetoresistive element body 41 can store binary data according to its resistance state.

[0024] The magnetoresistive element body 41 is an STT (spin transfer torque) type element and has perpendicular magnetization. That is, the magnetization direction of the memory layer 41a is perpendicular to its film surface, and the magnetization direction of the reference layer 41b is perpendicular to its film surface.

[0025] Figure 3B is a schematic cross-sectional view showing a modified configuration of the magnetoresistive element body 41.

[0026] The magnetoresistive element body 41 shown in Figure 3A was a bottom-free type element in which the memory layer 41a is located below the reference layer 41b. However, as shown in Figure 3B, a top-free type element in which the memory layer 41a is located above the reference layer 41b may also be used.

[0027] The lower electrode 42 functions as the lower electrode of the magnetoresistive element 40 and is formed of a conductive material containing elements selected from titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), scandium (Sc), yttrium (Y), and lanthanide elements.

[0028] Specifically, the lower electrode 42 may be formed of one or more of the above elements, or it may be formed of a compound of one or more of the above elements with other elements (for example, nitrogen (N), carbon (C), or boron (B)) (for example, a nitride, carbide, or boride of one or more of the above elements).

[0029] The upper electrode 43 functions as the upper electrode of the magnetoresistive element 40, is made of a conductive material, and includes a cap layer and a hard mask layer, etc.

[0030] The selector 50 is a two-terminal switching element and includes a selector material layer (switching material layer) 51, a lower electrode 52, and an upper electrode 53, and has a structure in which the selector material layer 51, the lower electrode 52, and the upper electrode 53 are stacked in the Z direction.

[0031] The selector material layer 51 is provided between the lower electrode 52 and the upper electrode 53 and is formed of, for example, a silicon oxide containing arsenic (As).

[0032] The lower electrode 52 functions as the lower electrode of the selector 50 and is formed of a conductive material such as titanium nitride (TiN).

[0033] The upper electrode 53 functions as the upper electrode of the selector 50 and has an upper surface connected to the lower surface of the magnetoresistive element 40, and includes an electrode portion (first electrode portion) 53a and an electrode portion (second electrode portion) 53b stacked in the Z direction.

[0034] The electrode portion 53a is connected to the lower surface of the magnetoresistive element 40 and is made of a conductive material such as titanium nitride (TiN).

[0035] The electrode portion 53b is connected to the lower surface of the electrode portion 53a and is made of a different material than the electrode portion 53a. Specifically, the electrode portion 53b is made of a conductive material containing carbon (C). That is, the electrode portion 53b may be made of carbon alone, or it may be made of a compound of carbon and other elements. By forming the electrode portion 53b with a carbon-containing material, it is possible to obtain a selector 50 with good properties.

[0036] Figure 4 is a schematic diagram showing the current-voltage characteristics of the selector 50.

[0037] As shown in Figure 4, the selector 50 has the characteristic of transitioning from the off state to the on state when the voltage applied between the two terminals (between the lower electrode 52 and the upper electrode 53) increases and reaches the threshold voltage Vth, and transitioning from the on state to the off state when the voltage applied between the two terminals decreases and reaches the hold voltage Vhold.

[0038] Therefore, when a voltage is applied between the wiring 10 and wiring 20 shown in Figure 1, and the voltage applied between the lower electrode 52 and upper electrode 53 of the selector 50 reaches the threshold voltage Vth, the selector 50 turns on, current flows through the magnetoresistive element 40 connected in series with the selector 50, and it becomes possible to write to or read from the magnetoresistive element 40.

[0039] Figure 5 schematically shows the relationship between the pattern on the lower surface of the magnetoresistive element 40 (the lower surface of the lower electrode 42 of the magnetoresistive element 40) and the pattern on the upper surface of the selector 50 (the upper surface of the upper electrode 53 of the selector 50). As shown in Figure 5, when viewed from the Z direction, the pattern on the upper surface 53U of the upper electrode 53 of the selector 50 is located inside the pattern on the lower surface 40L of the magnetoresistive element 40.

[0040] The insulating region 60 surrounds the magnetoresistive element 40 and selector 50 described above, and includes an insulating layer (first insulating layer) 61, an insulating layer 62, an insulating layer 63, an insulating layer 64, and an insulating layer (second insulating layer) 65.

[0041] The insulating layer 61 surrounds the sides of the upper electrode 53 of the selector 50 and has an upper surface positioned lower than the upper surface of the upper electrode 53. Specifically, the insulating layer 61 surrounds the sides of the electrode portion 53a of the upper electrode 53 and has a lower surface positioned higher than the upper surface of the electrode portion 53b of the upper electrode 53. Therefore, the insulating layer 61 does not surround the upper and lower sides of the electrode portion 53a of the upper electrode 53, but surrounds the sides of the intermediate portion between the upper and lower parts of the electrode portion 53a.

[0042] The insulating layer 61 is formed of amphoteric oxides such as aluminum (Al) oxide (usually Al2O3), zinc (Zn) oxide (usually ZnO), tin (Sn) oxide (usually SnO2), and lead (Pb) oxide (usually PbO2). Amphoteric oxides react to both acids and alkalis and are soluble in both acids and alkalis.

[0043] The insulating layer 62 is provided on the upper side of the insulating layer 61 and is made of a different material (for example, silicon oxide) than the insulating layer 61. The insulating layer 62 surrounds the entire side surface of the magnetoresistive element 40 and also surrounds the upper side surface of the electrode portion 53a of the upper electrode 53 of the selector 50.

[0044] The insulating layer 63 is provided on the lower side of the insulating layer 61 and is made of a different material (for example, silicon nitride) than the insulating layer 61. The insulating layer 63 surrounds the entire side surface of the selector material layer 51 of the selector 50, the lower electrode 52, and the electrode portion 53b of the upper electrode 53, and also surrounds the side surface of the lower portion of the electrode portion 53a of the upper electrode 53 of the selector 50.

[0045] The insulating layer 64 is provided on the lower side of the insulating layer 63 and is made of a different material (for example, silicon oxide) than the insulating layer 61. The insulating layer 64 is provided so as to cover the sides of the wiring 10.

[0046] The insulating layer 65 functions as a sidewall insulating layer for the magnetoresistive element 40, is provided along the side (sidewall) of the magnetoresistive element 40, and is made of a different material (e.g., silicon nitride) than the insulating layer 61. The insulating layer 65 is provided between the magnetoresistive element 40 and the insulating layer 62, and surrounds the entire side of the magnetoresistive element 40.

[0047] Next, the method for manufacturing the magnetic storage device according to this embodiment will be described with reference to Figures 6A to 11A (cross-sectional views parallel to the X direction) and Figures 6B to 11B (cross-sectional views parallel to the Y direction).

[0048] First, as shown in Figures 6A and 6B, a structure including wiring 10, selector 50, and insulating layer 64 is formed on a lower region (not shown) including a semiconductor substrate (not shown).

[0049] Next, as shown in Figures 7A and 7B, an insulating layer 63 is formed to cover the structure obtained in the steps of Figures 6A and 6B. Subsequently, the insulating layer 63 is etched back to lower its upper surface. At this time, the etching back is performed so that the position of the upper surface of the insulating layer 63 is higher than the position of the upper surface of the electrode portion 53b of the upper electrode 53. Furthermore, an insulating layer 61 is formed on the etched-back insulating layer 63 to cover the electrode portion 53a of the upper electrode 53.

[0050] Next, as shown in Figures 8A and 8B, the insulating layer 61 is flattened by CMP (chemical mechanical polishing). This exposes the upper surface of the upper electrode 53.

[0051] Next, as shown in Figures 9A and 9B, a layer for the magnetoresistive element 40 is formed on the structure obtained in the process of Figures 8A and 8B, and then patterning is performed by IBE (ion beam etching). Specifically, first, a hard mask layer formed on the uppermost layer of the magnetoresistive element 40 is patterned to form a hard mask pattern. Then, using the hard mask pattern as a mask, the layer for the magnetoresistive element 40 located below the hard mask layer is etched by IBE. This gives rise to the magnetoresistive element 40. In addition, during the IBE process described above, the metal material etched by IBE is embedded in the insulating layer 61, and a residue layer 70 containing metal elements is formed near the upper surface of the insulating layer 61.

[0052] Next, as shown in Figures 10A and 10B, an insulating layer 65 is formed to cover the structure obtained in the process shown in Figures 9A and 9B. Specifically, the insulating layer 65 is formed to cover the entire surface (side and top surface) of the magnetoresistive element 40. Furthermore, the insulating layer 65 formed on the top surface of the magnetoresistive element 40 and on the insulating layer 61 is removed by anisotropic etching such as RIE (reactive ion etching), leaving the insulating layer 65 formed on the side (sidewall) of the magnetoresistive element 40.

[0053] Next, as shown in Figures 11A and 11B, the upper portion of the insulating layer 61 is etched using an alkaline solution. Specifically, wet etching is performed using an organic alkaline solution such as an aqueous solution of TMAH (tetramethyl ammonium hydroxide). Since the insulating layer 61 is formed of amphoteric oxide, it can be etched with an alkaline solution. During this etching process, the residue layer 70 is also removed along with the upper portion of the insulating layer 61 by lift-off.

[0054] During the etching process using the alkaline solution described above, the magnetoresistive element 40 is not etched because its sides are covered with an alkaline-resistant insulating layer 65 made of silicon nitride or the like. In particular, although the tunnel barrier layer of the magnetoresistive element 40 can be etched by the alkaline solution, the insulating layer 65 protects the tunnel barrier layer from the alkaline solution. Furthermore, the lower electrode 42 and upper electrode 43 of the magnetoresistive element 40, as well as the electrode portion 53a of the upper electrode 53 of the selector 50, are also not etched because they are made of alkaline-resistant materials. In addition, the insulating layer 61 has a lower surface positioned higher than the upper surface of the electrode portion 53b of the upper electrode 53 of the selector 50, and the sides of the electrode portion 53b are covered with the insulating layer 63. Therefore, even if the electrode portion 53b is made of a material containing carbon that is soluble in the alkaline solution, the electrode portion 53b can be protected from the alkaline solution.

[0055] After the steps shown in Figures 11A and 11B, the insulating layer 62 is formed to obtain the structure shown in Figures 2A and 2B.

[0056] As described above, in this embodiment, by providing an insulating layer 61 made of amphoteric oxide, as described below, it is possible to effectively remove the residue layer 70 without adversely affecting the magnetoresistive element 40.

[0057] If a residue layer 70 is formed in the region between adjacent magnetoresistive elements 40, there is a risk that the adjacent magnetoresistive elements 40 will become electrically conductive due to the residue layer 70. Therefore, it is desirable to effectively remove the residue layer 70.

[0058] In this embodiment, when forming the pattern of the magnetoresistive element 40 by IBE in the process shown in Figures 9A and 9B, the side surface of the electrode portion 53a of the upper electrode 53 of the selector 50 is covered with an insulating layer 61 made of amphoteric oxide. That is, the insulating layer 61 is provided in the region below the region between adjacent magnetoresistive elements 40. Therefore, during IBE, the residue layer 70 is formed in the region near the upper surface of the insulating layer 61. Since the insulating layer 61 is made of amphoteric oxide that can be etched with an alkaline solution, it is possible to effectively remove the residue layer 70 together with the insulating layer 61.

[0059] Furthermore, by using an alkaline solution, the residue layer 70 can be effectively removed without adversely affecting the magnetoresistive element 40. If the only goal is to remove the residue layer 70, a hydrofluoric acid-based etching solution can also be used. However, when a hydrofluoric acid-based etching solution is used, the magnetoresistive element 40 cannot be reliably protected from the etching solution, and for example, the lower electrode 42 of the magnetoresistive element 40 may also be etched.

[0060] In this embodiment, an amphoteric oxide is used for the insulating layer 61, and the residue layer 70 is removed together with the insulating layer 61 using an alkaline solution, thereby effectively removing the residue layer 70 without adversely affecting the magnetoresistive element 40. Therefore, in this embodiment, it is possible to prevent problems such as adjacent magnetoresistive elements 40 becoming electrically conductive due to the residue layer 70, and to accurately form the magnetoresistive element 40 without adversely affecting the magnetoresistive element 40.

[0061] (Second embodiment) Next, a second embodiment will be described. The basic aspects are the same as in the first embodiment, and explanations of the matters described in the first embodiment will be omitted.

[0062] Figures 12A and 12B are schematic cross-sectional views illustrating the basic configuration of the magnetic storage device according to this embodiment. Figure 12A is a cross-sectional view parallel to the X direction, and Figure 12B is a cross-sectional view parallel to the Y direction.

[0063] Similar to the first embodiment, the structure shown in Figures 12A and 12B is provided on a lower region (not shown) including a semiconductor substrate (not shown), and includes wiring 10, a memory cell 30 including a magnetoresistive element 40 and a selector (switching element) 50, and an insulating region 60. Although not shown in Figures 12A and 12B, wiring 20 shown in Figure 1 is usually provided on the upper side of the memory cell 30.

[0064] In the first embodiment, the upper electrode 53 of the selector 50 had a two-layer structure consisting of electrode portion 53a and electrode portion 53b, but in this embodiment, the upper electrode 53 has a single-layer structure. Specifically, in this embodiment, the upper electrode 53 is formed of a conductive material such as titanium nitride (TiN), similar to the electrode portion 53a in the first embodiment.

[0065] Furthermore, in the first embodiment, an insulating layer 63 was provided between the insulating layer 61 and the insulating layer 64, but in this embodiment, the insulating layer 63 is not provided, and an insulating layer 61 formed of the same amphoteric oxide as in the first embodiment is provided on the insulating layer 64.

[0066] Aside from the configuration described above, the basic configuration is the same as that of the magnetic storage device described in the first embodiment.

[0067] Next, the method for manufacturing the magnetic storage device according to this embodiment will be described with reference to Figures 13A to 18A (cross-sectional views parallel to the X direction) and Figures 13B to 18B (cross-sectional views parallel to the Y direction).

[0068] First, as shown in Figures 13A and 13B, a structure including wiring 10, selector 50, and insulating layer 64 is formed on a lower region (not shown) including a semiconductor substrate (not shown).

[0069] Next, as shown in Figures 14A and 14B, an insulating layer 61 is formed to cover the structure obtained in the steps of Figures 13A and 13B.

[0070] Next, as shown in Figures 15A and 15B, the insulating layer 61 is flattened by CMP. This exposes the upper surface of the upper electrode 53.

[0071] Next, as shown in Figures 16A and 16B, a layer for the magnetoresistive element 40 is formed on the structure obtained in the process shown in Figures 15A and 15B. Furthermore, the magnetoresistive element 40 is formed by patterning using IBE in the same manner as in the process shown in Figures 9A and 9B of the first embodiment. At this time, similar to the first embodiment, a residue layer 70 is formed near the upper surface of the insulating layer 61.

[0072] Next, as shown in Figures 17A and 17B, an insulating layer 65 is formed on the side surface (side wall) of the magnetoresistive element 40 in the same manner as the steps in Figures 10A and 10B of the first embodiment.

[0073] Next, as shown in Figures 18A and 18B, the upper portion of the insulating layer 61 is etched using an alkaline solution in the same manner as in the steps shown in Figures 11A and 11B of the first embodiment. In this embodiment as well, the insulating layer 61 is formed of an amphoteric oxide and can therefore be etched with an alkaline solution. As a result, similar to the first embodiment, the residue layer 70 is removed together with the upper portion of the insulating layer 61 by lift-off.

[0074] In this embodiment, as in the first embodiment, the sides of the magnetoresistive element 40 are covered with an alkali-resistant insulating layer 65 such as silicon nitride, so the magnetoresistive element 40 is not etched during the etching process using the alkali solution described above. In addition, the lower electrode 42 and upper electrode 43 of the magnetoresistive element 40 and the upper electrode 53 of the selector 50 are also formed from alkali-resistant materials and are therefore not etched.

[0075] After the steps shown in Figures 18A and 18B, the insulating layer 62 is formed to obtain the structure shown in Figures 12A and 12B.

[0076] As described above, in this embodiment as well, by using an amphoteric oxide for the insulating layer 61 and removing the residue layer 70 together with the insulating layer 61 using an alkaline solution, it is possible to effectively remove the residue layer 70 without adversely affecting the magnetoresistive element 40. Therefore, in this embodiment as well, it is possible to prevent problems such as adjacent magnetoresistive elements 40 becoming electrically conductive due to the residue layer 70, and it is possible to accurately form the magnetoresistive element 40 without adversely affecting the magnetoresistive element 40.

[0077] (Third embodiment) Next, a third embodiment will be described. The basic aspects are the same as in the first embodiment, and explanations of the matters described in the first embodiment will be omitted.

[0078] Figures 19A and 19B are schematic cross-sectional views illustrating the basic configuration of the magnetic storage device according to this embodiment. Figure 19A is a cross-sectional view parallel to the X direction, and Figure 19B is a cross-sectional view parallel to the Y direction.

[0079] Similar to the first and second embodiments, the structure shown in Figures 19A and 19B is provided on a lower region (not shown) including a semiconductor substrate (not shown). However, while in the first and second embodiments a selector 50 was connected to the wiring 10, in this embodiment a magnetoresistive element 40 is connected to the wiring 10. That is, the upper surface of the wiring 10 is connected to the lower surface of the magnetoresistive element 40. The basic structure of the magnetoresistive element 40 is the same as in the first embodiment.

[0080] Although not shown in Figures 19A and 19B, a selector 50 as described in the first embodiment may be provided on the upper side of the magnetoresistive element 40. In this case, the wiring 20 shown in Figure 1 may be provided on the upper side of the memory cell in which the magnetoresistive element 40 and the selector 50 are stacked in the Z direction.

[0081] In this embodiment, an insulating layer 61 made of an amphoteric oxide similar to that in the first embodiment is provided between insulating layer 62 and insulating layer 64. The insulating layer 61 is provided along two sides of the wiring 10 (two sides extending in the X direction). The insulating layer 61 also has an upper surface lower than the upper surface of the wiring 10 and a lower surface higher than the lower surface of the wiring 10.

[0082] Figure 20 is a schematic diagram showing the relationship between the pattern on the lower surface of the magnetoresistive element 40 (the lower surface of the lower electrode 42 of the magnetoresistive element 40) and the pattern on the upper surface of the wiring 10.

[0083] As shown in Figure 20, when viewed from the Z direction, the width of the pattern on the upper surface 10U of the wiring 10 in the direction perpendicular to the extension direction of the wiring 10 (corresponding to the X direction) (corresponding to the Y direction) is smaller than the maximum width of the pattern on the lower surface 40L of the magnetoresistive element 40 in the direction perpendicular to the extension direction of the wiring 10 (corresponding to the X direction) (corresponding to the Y direction). For example, if the pattern on the lower surface 40L of the magnetoresistive element 40 is a circular pattern, the width of the pattern on the upper surface 10U of the wiring 10 is smaller than the diameter of the circular pattern on the lower surface 40L of the magnetoresistive element 40.

[0084] Furthermore, in this embodiment, the wiring 10 includes a residue layer 70 containing the metal elements contained in the magnetoresistive element 40. That is, the upper surface of the wiring 10 includes a non-contact upper surface portion that does not contact the lower surface of the magnetoresistive element 40, outside of the contact upper surface portion that contacts the lower surface of the magnetoresistive element 10, and the wiring 10 includes a residue layer 70 containing the metal elements contained in the magnetoresistive element 40 near the non-contact upper surface portion.

[0085] Next, the method for manufacturing the magnetic storage device according to this embodiment will be described with reference to Figures 21A to 26A (cross-sectional views parallel to the X direction) and Figures 21B to 26B (cross-sectional views parallel to the Y direction).

[0086] First, as shown in Figures 21A and 21B, a structure including wiring 10 and an insulating layer 64 is formed on a lower region (not shown) including a semiconductor substrate (not shown). Specifically, the insulating layer 64 is formed to cover the wiring 10, and then the insulating layer 64 is flattened by CMP, exposing the upper surface of the wiring 10. This results in the structure shown in Figures 21A and 21B.

[0087] Next, as shown in Figures 22A and 22B, the insulating layer 64 is etched back to lower its upper surface. Subsequently, insulating layers 61 and 66 are formed to cover the structure thus obtained. Insulating layer 66 is used to form an alignment mark pattern.

[0088] Next, as shown in Figures 23A and 23B, insulating layers 61 and 66 are flattened by CMP. This exposes the upper surface of the wiring 10.

[0089] Next, as shown in Figures 24A and 24B, a layer for the magnetoresistive element 40 is formed on the structure obtained in the process of Figures 23A and 23B, and then patterning is performed by IBE in the same manner as in the process of Figures 9A and 9B of the first embodiment. This gives rise to the magnetoresistive element 40. In addition, metal material etched by IBE is embedded into the wiring 10 and the insulating layer 61, and a residue layer 70 containing metal material is formed near the upper surface of the wiring 10 and near the upper surface of the insulating layer 61.

[0090] Next, as shown in Figures 25A and 25B, an insulating layer 65 is formed on the side surface (side wall) of the magnetoresistive element 40 in the same manner as the steps in Figures 10A and 10B of the first embodiment.

[0091] Next, as shown in Figures 26A and 26B, the upper portion of the insulating layer 61 is etched using an alkaline solution in the same manner as in the steps shown in Figures 11A and 11B of the first embodiment. In this embodiment as well, the insulating layer 61 is formed of amphoteric oxide and is therefore etchable with an alkaline solution. As with the first embodiment, the residue layer 70 is removed along with the upper portion of the insulating layer 61 by lift-off. Since the wiring 10 is not etched by the alkaline solution, the residue layer 70 near the upper surface of the wiring 10 remains.

[0092] Furthermore, in this embodiment as in the first embodiment, the sides of the magnetoresistive element 40 are covered with an alkali-resistant insulating layer 65, and the lower electrode 42 and upper electrode 43 of the magnetoresistive element 40 are formed of an alkali-resistant material. Therefore, the magnetoresistive element 40 is not etched during the etching process using the alkali solution described above.

[0093] After the steps shown in Figures 26A and 26B, the insulating layer 62 is formed to obtain the structure shown in Figures 19A and 19B.

[0094] As described above, in this embodiment as well, by using an amphoteric oxide for the insulating layer 61 and removing the residue layer 70 together with the insulating layer 61 using an alkaline solution, it is possible to effectively remove the residue layer 70 without adversely affecting the magnetoresistive element 40. Therefore, in this embodiment as well, it is possible to prevent problems such as adjacent magnetoresistive elements 40 becoming electrically conductive due to the residue layer 70, and it is possible to accurately form the magnetoresistive element 40 without adversely affecting the magnetoresistive element 40.

[0095] Furthermore, in this embodiment, although a residue layer 70 remains near the upper surface of the wiring 10, the residue layer 70 remains only in the wiring portion connecting the adjacent magnetoresistive element 40. Therefore, in this embodiment, even if a residue layer 70 remains near the upper surface of the wiring 10, no particular problem arises.

[0096] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0097] 10…Wiring 10U…Top surface 20…Wiring 30…Memory cell 40...Magnetoresistive element 40L...Bottom surface 41…Magnetoresistive element body 41a...Memory layer (first magnetic layer) 41b...Reference layer (second magnetic layer) 41c...Tunnel barrier layer (non-magnetic layer) 42...Lower electrode 43...Upper electrode 50...Selector 51…Selector material layer (switching material layer) 52...Lower electrode 53...Upper electrode 53U...Top surface 53a... Electrode portion (first electrode portion) 53b... Electrode portion (second electrode portion) 60...Insulation area 61...Insulating layer (first insulating layer) 62, 63, 64, 66...Insulating layer 65…Insulating layer (second insulating layer) 70...Residue layer

Claims

1. A magnetoresistive element having a structure in which the first magnetic layer, the second magnetic layer, and the non-magnetic layer are stacked, comprising a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a non-magnetic layer provided between the first magnetic layer and the second magnetic layer, An electrode having an upper surface connected to the lower surface of the magnetoresistive element, A first insulating layer, formed of an amphoteric oxide, surrounds the side surface of the electrode and has an upper surface lower than the upper surface of the electrode. A magnetic storage device characterized by comprising the following features.

2. The magnetoresistive element further comprises a switching element provided on the lower layer side, The electrode functions as the upper electrode of the switching element. The magnetic storage device according to claim 1.

3. The electrode includes a first electrode portion connected to the lower surface of the magnetoresistive element, and a second electrode portion connected to the lower surface of the first electrode portion and made of a different material from the material of the first electrode portion. The magnetic storage device according to claim 1.

4. The first insulating layer surrounds the side surface of the first electrode portion. The magnetic storage device according to claim 3.

5. The first insulating layer has a lower surface positioned higher than the upper surface of the second electrode portion. The magnetic storage device according to claim 3.

6. The second electrode portion contains carbon (C). The magnetic storage device according to claim 3.

7. When viewed from the direction in which the first magnetic layer, the second magnetic layer, and the non-magnetic layer are stacked, the pattern on the upper surface of the electrode is located inside the pattern on the lower surface of the magnetoresistive element. The magnetic storage device according to claim 1.

8. A magnetoresistive element having a structure in which the first magnetic layer, the second magnetic layer, and the non-magnetic layer are stacked, comprising a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a non-magnetic layer provided between the first magnetic layer and the second magnetic layer, A wiring having an upper surface connected to the lower surface of the magnetoresistive element, A first insulating layer is provided along the side surface of the wiring, has an upper surface lower than the upper surface of the wiring, and is made of an amphoteric oxide, A magnetic storage device characterized by comprising the following features.

9. The upper surface of the wiring includes a non-contact upper surface portion that does not contact the lower surface of the magnetoresistive element, outside of the contact upper surface portion that contacts the lower surface of the magnetoresistive element. The wiring contains the metal element contained in the magnetoresistive element near the non-contact upper surface portion. The magnetic storage device according to claim 8.

10. When viewed from the direction in which the first magnetic layer, the second magnetic layer, and the non-magnetic layer are stacked, the width of the pattern on the upper surface of the wiring in a direction perpendicular to the extension direction of the wiring is smaller than the maximum width of the pattern on the lower surface of the magnetoresistive element in a direction perpendicular to the extension direction of the wiring. The magnetic storage device according to claim 8.

11. The aforementioned amphoteric oxide is selected from aluminum (Al) oxide, zinc (Zn) oxide, tin (Sn) oxide, and lead (Pb) oxide. The magnetic storage device according to claim 1 or 8.

12. The magnetoresistive element further includes a lower electrode containing an element selected from titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), scandium (Sc), yttrium (Y), and lanthanide elements. The magnetic storage device according to claim 1 or 8.

13. The side surface of the magnetoresistive element is surrounded by a second insulating layer made of a material different from the material of the first insulating layer. The magnetic storage device according to claim 1 or 8.

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