Magnetic storage device

Abstract

Provided is a magnetic memory device having excellent characteristics and reliability. A magnetic memory device according to an embodiment includes: a first wiring extending in a first direction; a second wiring provided on the upper layer side of the first wiring and extending in a second direction intersecting the first direction; a memory cell provided between the first wiring and the second wiring, having a lower surface connected to the first wiring and an upper surface connected to the second wiring, and including a magnetoresistive effect element and a switching element stacked in a third direction intersecting the first direction and the second direction; and a contact having an upper surface connected to the second wiring, the upper surface of the contact being located at a position higher than the upper surface of the memory cell.

Description

Technical Field

[0001] Embodiments of the present invention relate to magnetic storage devices. Background Art

[0002] A magnetic storage device is proposed in which a plurality of storage cells each including a magnetoresistive element and a selector (switching element) are integrated on a semiconductor substrate. Summary of the invention

[0003] Provided is a magnetic storage device having excellent characteristics and reliability.

[0004] The magnetic storage device involved in the embodiment comprises: a first wiring extending in a first direction; a second wiring arranged on the upper side of the first wiring and extending in a second direction intersecting the first direction; a storage unit arranged between the first wiring and the second wiring, having a lower surface connected to the first wiring and an upper surface connected to the second wiring, including a magnetoresistance effect element and a switching element stacked in a third direction intersecting the first direction and the second direction; and a contact piece having an upper surface connected to the second wiring, the upper surface of the contact piece being located at a higher position than the upper surface of the storage unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is a plan pattern diagram schematically showing the configuration (structure) of the magnetic storage device according to the first embodiment, viewed from the Z direction.

[0006] Figure 2 It is a cross-sectional view perpendicular to the X direction and schematically shows the structure of the magnetic storage device according to the first embodiment.

[0007] Figure 3 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the first embodiment.

[0008] Figure 4 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the first embodiment.

[0009] Figure 5 It is a cross-sectional view schematically showing a basic structure of a magnetoresistive element of the magnetic storage device according to the first embodiment.

[0010] Fig. 6A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0011] Figure 6B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0012] Fig. 7A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0013] Figure 7B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0014] Fig. 8A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0015] Figure 8B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the first embodiment.

[0016] Fig. 9 It is a schematic plan view schematically showing the structure of the magnetic storage device according to the second embodiment, viewed from the Z direction.

[0017] Fig.10 It is a cross-sectional view perpendicular to the X direction and schematically shows the structure of the magnetic storage device according to the second embodiment.

[0018] Fig.11 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the second embodiment.

[0019] Fig.12 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the second embodiment.

[0020] Fig.13A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0021] Fig. 13B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0022] Fig.14A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0023] Fig. 14B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0024] Fig.15A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0025] Fig. 15B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0026] Fig.16A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0027] Fig. 16B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0028] Fig.17A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0029] Fig. 17B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0030] Fig.18A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0031] Fig.18B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the second embodiment.

[0032] Fig.19 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the third embodiment.

[0033] Fig. 20 It is a cross-sectional view perpendicular to the Y direction and schematically shows the structure of the magnetic storage device according to the third embodiment.

[0034] Fig.21A It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the third embodiment.

[0035] Fig. 21B It is a cross-sectional view schematically showing a part of the method for manufacturing the magnetic storage device according to the third embodiment.

[0036] Description of Reference Numerals

[0037] 10 word lines (1st wiring);

[0038] 20 bit line (second wiring); 21 upper portion; 22 lower portion;

[0039] 30 storage unit; 31 magnetoresistance effect element;

[0040] 32 selector material layer (switch material layer); 33 lower electrode;

[0041] 34 upper electrode; 35 middle electrode; 36 selector (switching element);

[0042] 40 contact member; 40a upper portion; 40b lower portion;

[0043] 41: first contact part; 42: second contact part;

[0044] 50 lower wiring;

[0045] 61, 62, 63, 64, 65, 66 insulation layer;

[0046] 70 recessed portion; 80 side wall layer. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments will be described with reference to the drawings.

[0048] (First embodiment)

[0049] Figure 1 1 is a schematic plan view showing the structure of the magnetic storage device according to the first embodiment, viewed from the Z direction. Figure 1 It is a schematic plan view schematically showing the planar modes (patterns) of each of a plurality of components included in the magnetic storage device.

[0050] Figure 2 is a cross-sectional view perpendicular to the X direction and schematically showing the structure of the magnetic storage device according to the present embodiment, and Figure 1 The cross section corresponds to the AA line. Figure 3 is a cross-sectional view perpendicular to the Y direction and schematically showing the structure of the magnetic storage device according to the present embodiment. Figure 1 The cross section of the BB line corresponds to that of the BB line. Figure 4 is a cross-sectional view perpendicular to the Y direction and schematically showing the structure of the magnetic storage device according to the present embodiment. Figure 1 The cross section of the CC line corresponds to Figure 3 and Figure 4 In the figure, the lower area of ​​the storage unit 30 is omitted, but in fact Figure 2 Similarly, word lines 10 and the like are provided.

[0051] In addition, the X direction, the Y direction, and the Z direction shown in each figure are directions intersecting with each other. Specifically, the X direction, the Y direction, and the Z direction are orthogonal to each other.

[0052] The magnetic storage device of this embodiment includes a plurality of word lines (first wirings) 10, a plurality of bit lines (second wirings) 20, a plurality of memory cells 30, a plurality of contacts 40, a plurality of lower wirings 50, and a plurality of insulating layers 61 to 66. The above components are provided on a semiconductor substrate (not shown).

[0053] The plurality of word lines 10 are arranged in the Y direction at the same interval and extend in the X direction respectively.

[0054] The plurality of bit lines 20 are provided on the upper layer side of the plurality of word lines 10 , are arranged in the X direction at the same pitch, and extend in the Y direction respectively.

[0055] A plurality of memory cells 30 are arranged in the X direction and the Y direction. Each memory cell 30 is disposed between a corresponding word line 10 and a corresponding bit line 20 , and has a lower surface connected to the word line 10 and an upper surface connected to the bit line 20 .

[0056] Each memory cell 30 includes a magnetoresistance effect element 31, a selector material layer (switch material layer) 32, a lower electrode 33, an upper electrode 34, and an intermediate electrode 35, and these components are stacked in the Z direction. The selector (switch element) 36 is substantially composed of the selector material layer 32, the lower electrode 33, and the intermediate electrode 35, and the magnetoresistance effect element 31 is stacked on the upper layer side of the selector 36.

[0057] Figure 5 It is a cross-sectional view schematically showing a basic structure of the magnetoresistive effect element 31 .

[0058] The magnetoresistance effect element 31 is an MTJ (magnetic tunnel junction) element, including a storage layer (first magnetic layer) 31a, a reference layer (second magnetic layer) 31b and a tunnel barrier layer (non-magnetic layer) 31c, and has a structure in which these storage layer 31a, reference layer 31b and tunnel barrier layer 31c are stacked in the Z direction.

[0059] The storage layer 31a is a ferromagnetic layer having a variable magnetization direction. The variable magnetization direction means that the magnetization direction changes with respect to a predetermined write current. The reference layer 31b is a ferromagnetic layer having a fixed magnetization direction. The fixed magnetization direction means that the magnetization direction does not change with respect to a predetermined write current. The tunnel barrier layer 31c is an insulating layer provided between the storage layer 31a and the reference layer 31b.

[0060] In the case where the magnetization direction of the storage layer 31a is parallel to the magnetization direction of the reference layer 31b, the magnetoresistance effect element 31 presents a low resistance state with a relatively low resistance. In the case where the magnetization direction of the storage layer 31a is antiparallel to the magnetization direction of the reference layer 31b, the magnetoresistance effect element 31 presents a high resistance state with a relatively high resistance. Therefore, the magnetoresistance effect element 31 can store binary data according to its resistance state.

[0061] In addition, Figure 5 In the example shown, a bottom-free type magnetoresistance effect element is shown in which the storage layer 31a is located on the lower side of the reference layer 31b, but a top-free type magnetoresistance effect element can also be used in which the storage layer 31a is located on the upper side of the reference layer 31b.

[0062] The selector 36 is a two-terminal switch element, which is composed of a selector material layer 32, a lower electrode 33, and an intermediate electrode 35. For example, the selector material layer 32 is formed of silicon oxide to which arsenic (As) or the like is added. The selector 36 has a characteristic of switching from a cutoff (OFF) state to a conduction (ON) state when a voltage applied between the two terminals becomes equal to or higher than a threshold voltage. Figure 2 and Figure 3 When the voltage applied between the lower electrode 33 and the intermediate electrode 35 becomes equal to or higher than the threshold voltage, the resistance value of the selector material layer 32 is greatly reduced, and the selector 36 switches from the off state to the on state.

[0063] A voltage is applied between the word line 10 and the bit line 20. When the voltage applied to the selector 36 becomes equal to or higher than the threshold voltage, the selector 36 switches from the off state to the on state. As a result, a current flows through the magnetoresistive element 31 connected in series with the selector 36, and writing or reading can be performed on the magnetoresistive element 31.

[0064] The contact 40 functions as a contact electrode for the bit line 20, is formed of a metal material such as tungsten (W), and includes a first contact portion 41 and a second contact portion 42. The contact 40 has an upper surface connected to the bit line 20, and the upper surface of the contact 40 is located at a position higher than the upper surface of the memory cell 30. The lower surface of the contact 40 is connected to the lower wiring 50. Therefore, a signal is transmitted between the memory cell 30 and the lower wiring 50 via the bit line 20 and the contact 40. In addition, molybdenum (Mo) or copper (Cu) or the like may be used for the contact 40.

[0065] The maximum width of the contact 40 in the X direction is larger than the maximum width of the bit line 20 in the X direction. Strictly speaking, in the direction perpendicular to the extending direction (Y direction) of the bit line 20, the maximum width of the contact 40 is larger than the maximum width of the bit line 20. Therefore, when viewed from the Z direction, a part of the pattern of the contact 40 is located outside the pattern of the bit line 20.

[0066] In addition, if Figure 4 As shown, the contact 40 (the first contact part 41 in the example shown) includes an upper part 40a and a lower part 40b, wherein the upper part 40a includes an upper surface connected to the bit line 20, and the lower part 40b is located below the upper part 40a. When viewed from the Y direction, the side surface of the upper part 40a of the contact 40 is aligned with the side surface of the bit line 20 (aligned, consistent, and in a line). At the boundary between the upper part 40a of the contact 40 and the lower part 40b of the contact 40, the width of the upper part 40a in the X direction (strictly speaking, the width in the direction perpendicular to the Y direction) is smaller than the width of the lower part 40b in the X direction (strictly speaking, the width in the direction perpendicular to the Y direction). Therefore, there is a level difference (height difference) in the boundary area between the upper part 40a and the lower part 40b.

[0067] As described above, the upper surface of the contact 40 is located at a position higher than the upper surface of the memory cell 30. Specifically, a recess 70 is provided in a region where a plurality of memory cells 30 are arranged, and a portion of the bottom surface of the recess 70 corresponds to the upper surface of the memory cell 30. Since the bit line 20 is connected to the upper surface of the memory cell 30 and the upper surface of the contact 40, the thickness of the bit line 20 at the position connected to the upper surface of the memory cell 30 is thicker than the thickness of the bit line 20 at the position connected to the upper surface of the contact 40.

[0068] Therefore, if the thickness direction (height direction, Z direction) of the bit line 20 is considered, the bit line 20 includes an upper portion 21 and a lower portion 22. The upper portion 21 is arranged in the entire extension direction (Y direction) of the bit line 20, and the lower portion 22 is arranged in the recess 70. In other words, the upper portion 21 of the bit line 20 is located between the first plane including the connection surface between the contact 40 and the bit line 20 and the upper surface of the bit line 20, and the lower portion 22 of the bit line 20 is located between the second plane including the connection surface between the memory cell 30 and the bit line 20 and the first plane. In the present embodiment, the upper portion 21 and the lower portion 22 of the bit line 20 are formed by a common patterning process. Therefore, when viewed from the Y direction, a pair of side surfaces of the lower portion 22 of the bit line 20 are aligned with a pair of side surfaces of the upper portion 21 of the bit line 20.

[0069] In this embodiment, the upper portion 21 and the lower portion 22 of the bit line 20 are formed of the same conductive material. Specifically, the upper portion 21 and the lower portion 22 of the bit line 20 are both formed of a metal material such as tungsten (W). Molybdenum (Mo) or copper (Cu) may be used instead of tungsten. In addition, the word line 10 may also be made of a metal material such as tungsten, molybdenum or copper.

[0070] The insulating layers 61 to 66 function as interlayer insulating layers, etc. For example, the insulating layers 61 , 63 , 65 , and 66 are formed of silicon oxide, and the insulating layers 62 and 64 are formed of silicon nitride.

[0071] Next, refer to Fig. 6A and Figure 6B to Figure 8A and Figure 8B The cross-sectional view shown, and Figure 1 to Figure 4 , a method for manufacturing the magnetic storage device involved in this embodiment is described. Figures 6A to 8A is with Figure 3 The positions of the cross-sections shown correspond to the positions of the cross-sections in the figure. Figure 6B to Figure 8B is with Figure 4 The positions of the cross-sections shown correspond to the positions of the cross-sectional views.

[0072] First, if Fig. 6A and Figure 6B As shown, a structure including the memory cell 30, the contact 40, the insulating layer 61, the insulating layer 62, etc. is formed on a lower structure (not shown) including a semiconductor substrate. Fig. 6A and Figure 6B The upper surface of the illustrated construction is planarized, with the upper surface of the contact 40 exposed.

[0073] Then, if Fig. 7A and Figure 7B As shown, a portion of the insulating layer 62 is etched. As a result, a recess 70 is formed in the region where the plurality of memory cells 30 are arranged, and the upper surface of the memory cell 30 (the upper surface of the upper electrode 34) is exposed. The insulating layer 61 and the insulating layer 62 are formed of different materials. For example, the insulating layer 61 is formed of silicon oxide, and the insulating layer 62 is formed of silicon nitride. Therefore, by selectively etching the insulating layer 62 relative to the insulating layer 61, the recess 70 can be formed.

[0074] Then, if Fig. 8A and Figure 8B As shown, through Fig. 7A and Figure 7BOn the structure obtained by the process, a metal layer (for example, a tungsten layer) is formed as a conductive layer 20s for the bit line 20. Specifically, by forming the conductive layer 20s on the entire surface and then flattening it by CMP (chemical mechanical polishing), a conductive layer 20s having a flattened upper surface can be obtained.

[0075] Afterwards, if Figure 3 and Figure 4 As shown, the conductive layer 20s is patterned into a linear shape by selectively etching the material of the conductive layer 20s to form a plurality of bit lines 20. At this time, the thickness of the conductive layer 20s is thicker in the region where the memory cell 30 is provided (the region where the recess 70 is provided) than in the region where the contact 40 is provided. In addition, the conductive layer 20s is patterned in such a manner that the width of the bit line 20 becomes smaller than the width of the contact 40 when viewed from the Y direction. In addition, the bit line 20 and the contact 40 are formed of the same conductive material (metal material such as tungsten). Therefore, a portion of the upper portion 40a of the contact 40 is also etched, and the side surface of the upper portion 40a of the contact 40 is aligned with the side surface of the bit line 20, and the width of the upper portion 40a of the contact 40 becomes smaller than the width of the lower portion 40b of the contact 40.

[0076] Furthermore, by forming the insulating layer 66, a structure having the following characteristics can be obtained: Figure 1 to Figure 4 A magnetic storage device of the structure shown.

[0077] As described above, in the present embodiment, the upper surface of the contact 40 is located at a position higher than the upper surface of the memory cell 30. Thus, a magnetic memory device having excellent characteristics and reliability can be obtained as described below.

[0078] As described above, the width of the contact 40 is larger than that of the bit line 20, so it is important to reliably isolate the contact 40 from the bit line 20 adjacent to the contact 40. Therefore, when forming the pattern of the bit line 20 by etching, it is preferable to reduce the width of the upper portion 40a of the contact 40 by over-etching.

[0079] On the other hand, if excessive over-etching is performed at the position where the memory cell 30 is provided, the memory cell 30 may be damaged by etching, which may have an adverse effect on the characteristics and reliability of the memory cell 30. In particular, when the magnetoresistive element 31 is stacked on the upper layer side of the selector 36, the characteristics and reliability of the magnetoresistive element 31 may be greatly reduced.

[0080] In the present embodiment, the upper surface of the contact 40 is located at a higher position than the upper surface of the memory cell 30. That is, the upper surface of the memory cell 30 is located at a lower position than the upper surface of the contact 40. Therefore, even if the conductive layer 20s for the bit line 20 is sufficiently overetched in the region where the contact 40 is provided, the overetching amount of the conductive layer 20s can be accurately suppressed in the region where the memory cell 30 is provided.

[0081] Therefore, in this embodiment, the conductive layer 20s for the bit line 20 can be accurately etched in both the region where the contact 40 is provided and the region where the memory cell 30 is provided, and a magnetic memory device having excellent characteristics and reliability can be obtained.

[0082] (Second embodiment)

[0083] Next, a magnetic storage device according to the second embodiment will be described. In addition, the basic matters are the same as those of the first embodiment, and the description of the matters described in the first embodiment will be omitted.

[0084] Fig. 9 It is a schematic plan view viewed from the Z direction, schematically showing the configuration of the magnetic storage device according to the present embodiment.

[0085] Fig.10 is a cross-sectional view perpendicular to the X direction and schematically showing the structure of the magnetic storage device according to the present embodiment, and Fig. 9 The cross section corresponds to the AA line. Fig.11 is a cross-sectional view perpendicular to the Y direction and schematically showing the structure of the magnetic storage device according to the present embodiment. Fig. 9 The cross section of the BB line corresponds to that of the BB line. Fig.12 is a cross-sectional view perpendicular to the Y direction and schematically showing the structure of the magnetic storage device according to the present embodiment. Fig. 9 The cross section of the CC line corresponds to Fig.11 and Fig.12 In the figure, the lower area of ​​the storage unit 30 is omitted, but in fact Fig.10 Similarly, word lines 10 and the like are provided.

[0086] In the first embodiment, the upper portion 21 and the lower portion 22 of the bit line 20 are formed of the same conductive material, but in the present embodiment, the upper portion 21 and the lower portion 22 of the bit line 20 are formed of different conductive materials. Specifically, in the present embodiment, the upper portion 21 of the bit line 20 is formed of a metal material such as tungsten (W) as in the first embodiment. The lower portion 22 of the bit line 20 is formed of a conductive material containing carbon (C), ruthenium (Ru) or silicon (Si). More specifically, the lower portion 22 of the bit line 20 is formed of a conductive material containing carbon as a main component, a conductive material containing ruthenium as a main component, or a conductive material containing silicon as a main component. In the present embodiment, the lower portion 22 of the bit line 20 is formed of a conductive material containing substantially only carbon.

[0087] Next, refer to Fig.13A and Figures 13B to 18A and Fig.18B The cross-sectional view shown, and Figures 9 to 12 , a method for manufacturing the magnetic storage device involved in this embodiment is described. Figures 13A to 18A is with Fig.11 The positions of the cross-sections shown correspond to the positions of the cross-sections in the figure. Figure 13B to Figure 18B is with Fig.12 The positions of the cross-sections shown correspond to the positions of the cross-sectional views.

[0088] Fig.13A and Fig. 13B The process and Fig.14A and Fig. 14B The steps of the first embodiment are respectively Fig. 6A and Figure 6B The process and Fig. 7A and Figure 7B The process is the same as Fig.14A and Fig. 14B As shown, a recess 70 is formed in a region where a plurality of memory cells 30 are arranged.

[0089] Then, if Fig.15A and Fig. 15B As shown, through Fig.14A and Fig. 14B On the structure obtained by the process, a carbon layer is formed as a conductive layer 22s for the lower portion 22 of the bit line 20.

[0090] Then, if Fig.16A and Fig. 16B As shown in FIG. 1 , a planarization process is performed by CMP to planarize the upper surface of the conductive layer 22 s . By this planarization process, the conductive layer 22 s remains only in the concave portion 70 .

[0091] Then, if Fig.17A and Fig. 17B As shown, through Fig.16A and Fig. 16B On the structure obtained by the process, a metal layer (for example, a tungsten layer) is formed as a conductive layer 21s for the upper portion 21 of the bit line 20.

[0092] Then, if Fig.18A and Fig.18B As shown, the conductive layer 21s is patterned into a line shape by selectively etching the material of the conductive layer 21s, thereby forming the upper portion 21 of the plurality of bit lines 20. At this time, etching is performed under the condition that the etching rate of the conductive layer 21s is sufficiently higher than the etching rate of the conductive layer 22s. As a result, in the region where the memory cell 30 is provided (the region where the recess 70 is provided), the conductive layer 22s functions as an etching stopper layer, and the conductive layer 22s is hardly etched, and the conductive layer 21s is selectively etched.

[0093] On the other hand, in the region where the contact 40 is provided, as described in the first embodiment, the conductive layer 21s is patterned so that the width of the bit line 20 becomes smaller than the width of the contact 40 when viewed from the Y direction. In addition, the upper portion 21 of the bit line 20 and the contact 40 are formed of the same metal material (for example, tungsten). Therefore, a part of the upper portion 40a of the contact 40 is also etched, and the side surface of the upper portion 40a of the contact 40 is aligned with the side surface of the upper portion 21 of the bit line 20, and the width of the upper portion 40a of the contact 40 becomes smaller than the width of the lower portion 40b of the contact 40.

[0094] Afterwards, if Fig.11 and Fig.12 As shown, by selectively etching the material of the conductive layer 22s, the lower portions 22 of the plurality of bit lines 20 are formed. At this time, since the upper portions 21 of the bit lines 20 function as an etching mask, a pair of side surfaces of the lower portions 22 of the bit lines 20 are aligned with a pair of side surfaces of the upper portions 21 of the bit lines 20 when viewed from the Y direction.

[0095] Furthermore, by forming the insulating layer 66, a structure having the following characteristics can be obtained: Figures 9 to 12 A magnetic storage device of the structure shown.

[0096] As described above, the basic structure of this embodiment is the same as that of the first embodiment, and the same effects as those of the first embodiment can be obtained in this embodiment. In addition, in this embodiment, the conductive material of the lower portion 22 of the bit line 20 is different from the conductive material of the upper portion 21 of the bit line 20, and when the pattern of the upper portion 21 of the bit line 20 is formed, the conductive layer 22s of the lower portion 22 of the bit line 20 functions as an etching stopper. Therefore, overetching of the bit line 20 in the region where the memory cell 30 is provided can be more accurately suppressed.

[0097] (Third embodiment)

[0098] Next, a magnetic storage device according to the third embodiment will be described. In addition, the basic matters are the same as those of the first and second embodiments, and the description of the matters described in the first and second embodiments will be omitted.

[0099] The schematic plan view of the magnetic storage device according to the present embodiment as viewed from the Z direction is similar to that of the second embodiment. Fig. 9 The planar schematic diagram shown is the same. In addition, the cross-sectional view perpendicular to the X direction (the same as the cross-sectional view along the X direction) of the magnetic storage device according to this embodiment Fig. 9 The cross-sectional view corresponding to the cross-sectional view along the AA line of the second embodiment Fig.10 The cross-sectional views shown are identical.

[0100] Fig.19 is a cross-sectional view perpendicular to the Y direction of the magnetic storage device according to the present embodiment, and is Fig. 9 The cross section of the BB line corresponds to that of the BB line. Fig. 20 is a cross-sectional view perpendicular to the Y direction of the magnetic storage device according to the present embodiment, and is Fig. 9 The cross section of the CC line corresponds to Fig.19 and Fig. 20 In the figure, the lower area of ​​the storage unit 30 is omitted, but in fact Fig.10 Similarly, word lines 10 and the like are provided.

[0101] In this embodiment, as in the second embodiment, the upper portion 21 and the lower portion 22 of the bit line 20 are formed of different conductive materials. The conductive material of the upper portion 21 and the conductive material of the lower portion 22 are the same as in the second embodiment.

[0102] In this embodiment, a pair of sidewall layers 80 are provided along a pair of side surfaces of the upper portion 21 of the bit line 20. When viewed from the Y direction, a pair of side surfaces of the lower portion 22 of the bit line 20 are aligned with a pair of side surfaces of the pair of sidewall layers 80. The pair of sidewall layers 80 are formed of an insulating material such as silicon nitride.

[0103] Next, refer to Fig.21A and Fig. 21B The cross-sectional view shown, and Fig.19 and Fig. 20 , a method for manufacturing the magnetic storage device involved in this embodiment is described. Fig.21A is with Fig.19 The positions of the cross-sections shown correspond to the positions of the cross-sections in the figure. Fig. 21B is with Fig. 20 The positions of the cross-sections shown correspond to the positions of the cross-sectional views.

[0104] First, the same method as in the second embodiment is performed. Fig.13A and Figures 13B to 18A and Fig.18B The same process as the process of Fig.18A and Fig.18B The structure shown.

[0105] Then, if Fig.21A and Fig. 21B As shown, a pair of sidewall layers 80 are formed along a pair of side surfaces of the upper portion 21 of the bit line 20. Specifically, Fig.18A and Fig.18B An insulating layer for forming the sidewall layer 80 is formed on the structure obtained by the process, and the formed insulating layer is etched by anisotropic etching such as RIE (reactive ion etching), thereby forming a pair of sidewall layers 80 along a pair of side surfaces of the upper portion 21 of the bit line 20. In addition, in the area where the contact 40 is provided, the sidewall layer 80 is also formed on the side surface of the upper portion 40a of the contact 40.

[0106] Afterwards, if Fig.19 and Fig. 20 As shown, by selectively etching the material of the conductive layer 22s, the lower portions 22 of the plurality of bit lines 20 are formed. At this time, the upper portions 21 of the bit lines 20 and the pair of sidewall layers 80 function as etching masks. Therefore, when viewed from the Y direction, the pair of side surfaces of the lower portions 22 of the bit lines 20 are aligned with the pair of side surfaces of the pair of sidewall layers 80.

[0107] Furthermore, by forming the insulating layer 66, a structure having the following characteristics can be obtained: Fig. 9 , Fig.10 , Fig.19 as well as Fig. 20 A magnetic storage device of the structure shown.

[0108] As described above, the basic structure of this embodiment is the same as that of the first and second embodiments, and the same effects as those of the first and second embodiments can be obtained in this embodiment. In addition, in this embodiment, when the conductive layer 22s is etched to form the lower portion 22 of the bit line 20, a pair of side surfaces of the upper portion 21 of the bit line 20 can be protected by a pair of sidewall layers 80. For example, when carbon is used as the material of the conductive layer 22s, the conductive layer 22s is etched using oxygen. In this case, by providing the sidewall layer 80, it is possible to suppress the upper portion 21 of the bit line 20 from being oxidized.

[0109] Furthermore, in the above-described first to third embodiments, the magnetoresistance effect element 31 is stacked on the upper layer side of the selector 36 , but the selector 36 may be stacked on the upper layer side of the magnetoresistance effect element 31 .

[0110] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and / or their variations are included in the scope and / or gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims

1. A magnetic storage device comprising: A first wiring extending in a first direction; a second wiring, provided on an upper layer side of the first wiring, and extending in a second direction intersecting the first direction; A memory cell, disposed between the first wiring and the second wiring, having a lower surface connected to the first wiring and an upper surface connected to the second wiring, and including a magnetoresistance effect element and a switch element stacked in a third direction intersecting the first direction and the second direction; as well as a contact having an upper surface connected to the second wiring, It is characterized in that An upper surface of the contact is located higher than an upper surface of the memory cell.

2. The magnetic storage device according to claim 1, characterized in that The thickness of the second wiring at a position connected to the upper surface of the memory cell is thicker than the thickness of the second wiring at a position connected to the upper surface of the contact.

3. The magnetic storage device according to claim 1, characterized in that A maximum width of the contact in a direction perpendicular to the second direction is larger than a maximum width of the second wiring in the direction perpendicular to the second direction.

4. The magnetic storage device according to claim 1, characterized in that The contact includes an upper portion and a lower portion, the upper portion having a side surface aligned with a side surface of the second wiring when viewed from the second direction, and the lower portion being located below the upper portion. At a boundary between an upper portion of the contact and a lower portion of the contact, a width of the upper portion of the contact in a direction perpendicular to the second direction is smaller than a width of the lower portion of the contact in the direction perpendicular to the second direction.

5. The magnetic storage device according to claim 1, characterized in that The second wiring includes an upper part and a lower part, the upper part is located between a first plane including a connection surface between the contact and the second wiring and an upper surface of the second wiring, and the lower part is located between a second plane including a connection surface between the storage unit and the second wiring and the first plane.

6. The magnetic storage device according to claim 5, characterized in that When viewed from the second direction, a pair of side surfaces of a lower portion of the second wiring is aligned with a pair of side surfaces of an upper portion of the second wiring.

7. The magnetic storage device according to claim 5, characterized in that An upper portion of the second wiring is formed of a metal material.

8. The magnetic storage device according to claim 5, characterized in that The upper portion of the second wiring and the lower portion of the second wiring are formed of the same conductive material.

9. The magnetic storage device according to claim 5, characterized in that: The upper portion of the second wiring and the lower portion of the second wiring are formed of different conductive materials.

10. The magnetic storage device according to claim 9, characterized in that The lower portion of the second wiring is formed of a conductive material containing carbon, ruthenium or silicon.

11. The magnetic storage device according to claim 9, characterized in that A pair of side wall layers are further provided along a pair of side surfaces of an upper portion of the second wiring.

12. The magnetic storage device according to claim 11, characterized in that When viewed from the second direction, a pair of side surfaces of the lower portion of the second wiring is aligned with a pair of side surfaces of the pair of sidewall layers.

13. The magnetic storage device according to claim 1, characterized in that The magnetoresistance effect element is stacked on the upper layer side of the switching element.

14. The magnetic storage device according to claim 1, characterized in that The magnetoresistance effect element includes a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer.

15. The magnetic storage device according to claim 1, characterized in that The switching element is a two-terminal type switching element and has a characteristic of switching from an off state to an on state when a voltage applied between the two terminals becomes equal to or higher than a threshold voltage.

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