JP2003332650A - Tunnel magnetoresistive element, its manufacturing method, magnetic memory device, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tunnel magnetoresistive (TMR) element that can improve the reliability of a magnetic memory device by preventing the formation of an excessive current route noncontributing to device characteristics of the memory device with a easily workable TMR structure, and to provide a method of manufacturing the TMR element, the magnetic memory device, and a method of manufacturing the memory device. <P>SOLUTION: The method of manufacturing the TMR element 13 constituted by putting a tunnel insulating layer 303 between first and second ferromagnetic layers 302 and 304 includes a step of forming a working stopping layer 21 in at least one of interfaces between the tunnel insulating layer 303 and ferromagnetic layers 302 and 304 and around the forming area of the TMR element 13 at the time of manufacturing the TMR element and stopping working performed on the second ferromagnetic layer 304 by means of the working stopping layer 21, and a step of working a layer underlying the working stopping layer 21 by forming a mask 53 covering the second ferromagnetic layer 304. In addition, the TMR element is mounted on the magnetic memory device. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel magnetoresistive element and a method of manufacturing the same, a magnetic memory device and a method of manufacturing the same, and more particularly, a tunnel magnetoresistive element having improved workability of the tunnel magnetoresistive element and a method of manufacturing the same. And a magnetic memory device and a manufacturing method thereof.

[0002]

2. Description of the Related Art With the dramatic spread of information communication equipment, especially small personal equipment such as portable terminals, the elements such as memory elements and logic elements are highly integrated, high speed and low power consumption. Higher performance is required such as electric power. In particular, non-volatile memory is considered to be an essential element in the ubiquitous age.

For example, even if the power supply is exhausted or a trouble occurs, or if the server and the network are disconnected due to some trouble, the non-volatile memory can protect important personal information. And high density of non-volatile memory,
Increasing capacity is becoming more and more important as a technology for replacing hard disks and optical disks, which are essentially impossible to miniaturize due to the presence of moving parts.

As the non-volatile memory, a flash memory using a semiconductor or an FRAM (Ferr) using a ferroelectric substance is used.
o electric Random Access Memory). However, the flash memory has a drawback that it is difficult to achieve high integration due to its complicated structure and the access time is as slow as about 100 ns. On the other hand, FRA
It has been pointed out that in M, the number of rewritable times is 10 ¹² to 10 ¹⁴ and durability is low to completely replace it with a static random access memory or a dynamic random access memory. Further, it has been pointed out that it is difficult to finely process the ferroelectric capacitor.

As a non-volatile memory which does not have these drawbacks, for example, “Wang et al., IEEE T
rans.Magn.33 (1997), 4498 '',
It is a magnetic memory called MRAM (Magnetic Random Access Memory) or MR (Magenetoresistance) memory.

In addition, TMR (Tunnel Magneto Resistanc
e) The effect is R. Meservey et al., “Pysics Reports” Vol.2
38 (1994), p.214-217, the rate of change in resistance was only 1% to 2% at room temperature, but recently T. Miyazaki e.
t al., “J.Magnetism & Magnetic Material” Vol.139 (1
995), L231, a resistance change rate of nearly 20% has been obtained, and attention has been focused on MRAM using the TMR effect.

Since the MRAM has a simple structure, high integration can be easily achieved, and the number of times of rewriting is predicted to be large because recording is performed by rotation of a magnetic moment. The access time is also expected to be extremely high, and it is already possible to operate at 100 MHz. R. Scheuerlein et al., “ISSCC Digest of Technic
al Papers ”(Feb. 2000), p.128-129.

As described above, the TMR element used in the MRAM, which has been receiving attention in recent years, has a structure in which a tunnel oxide film is sandwiched between two magnetic layers, and flows through the tunnel oxide film depending on the spin directions of the two magnetic layers. A memory element that performs memory is configured by utilizing the change in the intensity of current.

Here, a conventional method of manufacturing an MRAM structure will be described with reference to manufacturing step sectional views of FIGS.

First, although not shown, a transistor (for example, an insulated gate field effect transistor to be a read transistor) is formed on a substrate (for example, a semiconductor substrate) by using a CMOS transistor manufacturing technique, and then a first transistor for covering the transistor is formed. An insulating film is formed. Further, after forming wirings (for example, sense lines), electrodes and the like on the first insulating film, a second insulating film covering them is formed. Further, as shown in (1) of FIG. 6, a word line (for example, a write word line) 11 is formed on a second insulating film (not shown), and a third insulating film 43 is formed so as to cover the word line 11. Form.

The word line 1 thus formed.
On the third insulating film 43 above the antiferromagnetic material layer 30.
1, the first ferromagnetic layer 302, the tunnel insulating layer 303, the second ferromagnetic layer 304, and the cap layer 305 are sequentially formed from the lower layer.

Next, as shown in (2) of FIG. 6, first, a resist patterning technique is used to form a lead wiring serving as a connection circuit portion for connecting the TMR element and the transistor of the read circuit portion. A resist mask (not shown) is formed, the cap layer 305 to the antiferromagnetic material layer 301 are processed by ion milling using the resist mask to form a lead wiring (not shown), and then the resist mask is used. Remove. Further, a resist mask (not shown) is formed by a resist patterning technique, and the cap layer 305 to the antiferromagnetic material layer 301 are processed by ion milling using the resist mask to form the TMR element 13. After that, the resist mask is removed. In FIG. 6B, the state after the TMR element 13 is formed and the resist mask is removed is shown.

Thereafter, as shown in (3) of FIG.
After forming the fourth insulating film 44 on the insulating film 43 so as to cover the TMR element 13, for example, by depositing a silicon-based insulating film, the fourth insulating film 44 is polished by chemical mechanical polishing,
The surface of the cap layer 305 of the TMR element 13 is exposed.

Next, as shown in (4) of FIG.
A conductive layer 61 for forming a bit line is formed on the fourth insulating film 44 so as to cover the element 13. Thereafter, as shown in (5) of FIG. 6, the bit line 12 connected to the cap layer 305 of the TMR element 13 by processing the conductive layer 61 by the usual lithography technique and etching technique.
Are formed so as to cross three-dimensionally (orthogonally) with the TMR element 13 in between with respect to the word line 11. Then, the etching mask (not shown) used for this etching is removed. FIG. 6 (5) shows the state after removing the etching mask.

[0015]

However, when the antiferromagnetic material layer is processed from the cap layer to be the TMR element by ion milling, a processed product is generated and the TMR element is generated.
The processed product adheres to the side wall of the device. Since this processed product has conductivity, an unintended current path due to the processed product is generated on the sidewall of the TMR element.
There is a problem that the TMR element characteristics are deteriorated. This is the Extra Current Channel
s) (Olivier et al., 44th Ann)
ual Conference on Magnetism and Magnetic Materials
See AA-11 (1999)).

In order to prevent such deterioration of the characteristics of the TMR element, after etching the upper second ferromagnetic material layer, the etching is stopped on the tunnel insulating film and the lower first ferromagnetic material layer is separated. By etching with a mask, the conduction of the two ferromagnetic layers due to the adhesion of processed products is prevented,
There is a method of maintaining insulation between ferromagnetic layers. However, since the tunnel insulating film is very thin and has a film thickness of about 1 nm, it is very difficult to stop the etching with such an extremely thin tunnel insulating film in terms of processing.

The present invention has been made in view of the above problems, and an object thereof is to prevent the formation of an extra current path that does not contribute to the characteristics of the device by making the structure easy to process. A tunnel magnetoresistive element, a manufacturing method thereof, a magnetic memory device, and a manufacturing method thereof.

[0018]

SUMMARY OF THE INVENTION The present invention is a tunnel magnetoresistive element, a method of manufacturing the same, a magnetic memory device and a method of manufacturing the same, which have been made to solve the above problems.

The tunnel magnetoresistive element of the present invention is a tunnel magnetoresistive element constructed by sandwiching a tunnel insulating layer between ferromagnetic layers, wherein the tunnel insulating layer and the ferromagnetic layers sandwiching the tunnel insulating layer are provided. A processing stop layer is provided on at least one of the interfaces and around the tunnel magnetoresistive element formation region.

In the tunnel magnetoresistive element, a processing stop layer is provided at at least one of the interfaces between the tunnel insulating layer and the ferromagnetic layers sandwiching the tunnel insulating layer and around the tunnel magnetoresistive element forming region. Therefore, when processing the upper ferromagnetic layer forming the tunnel magnetoresistive element, it is necessary to stop the processing at the tunnel insulating layer formed of an extremely thin film with a thickness of about 0.5 nm to 5 nm. And the processing of the upper ferromagnetic layer can be performed up to the processing stop layer. for that reason,
The difficulty of processing is reduced.

The method of manufacturing a tunnel magnetoresistive element according to the present invention comprises the steps of forming a first ferromagnetic layer, forming a processing stop layer on the first ferromagnetic layer, and then forming a tunnel magnetoresistive element. A step of forming an opening at the bottom of which the first ferromagnetic layer is exposed in the processing stop layer on the region; and a tunnel insulating layer and a second ferromagnetic layer on the processing stop layer including the inside of the opening. A step of sequentially stacking a body layer and a cap layer from a lower layer, a step of processing from the cap layer to the tunnel insulating layer into a shape of a tunnel magnetoresistive element, and a mask covering the cap layer and the second ferromagnetic layer And then processing the processing stop layer and the first ferromagnetic layer.

Alternatively, after the tunnel insulating layer is formed on the first ferromagnetic layer, the processing stop layer is formed and an opening exposing the tunnel insulating layer at the bottom is formed, and then the second ferromagnetic layer is formed. The cap layers may be sequentially laminated. In this case, after processing the cap layer and the second ferromagnetic layer into the shape of the tunnel magnetoresistive element, the cap layer and the second ferromagnetic layer are formed.
A mask that covers the ferromagnetic layer is formed, and then the processing stop layer and the first ferromagnetic layer are processed.

In the tunnel magnetoresistive element manufacturing method, the tunnel magnetoresistive element is formed at at least one of the interfaces between the tunnel insulating layer and the first and second ferromagnetic layers sandwiching the tunnel insulating layer. Since the processing stop layer is provided around the region, the film thickness is 0.5 n when processing the second ferromagnetic layer forming the tunnel magnetoresistive element.
It is not necessary to stop the processing of the tunnel insulating layer formed of an ultrathin film of about m to 5 nm, and the processing of the second ferromagnetic layer is stopped at the processing stop layer. Therefore, the difficulty of processing is reduced.

Further, since the processing from the processing stop layer to the first ferromagnetic material layer is processed after forming the mask covering the cap layer and the second ferromagnetic material layer, a processed product having conductivity even during processing is formed. Even if occurs, since the cap layer and the second ferromagnetic material layer are covered with the mask, a processed product that connects the first ferromagnetic material layer and the cap layer or the second ferromagnetic material layer No adhesion occurs. Therefore, an unintended current path is not generated between the first and second ferromagnetic layers, and the problem of degrading the TMR element characteristics is solved.

The magnetic memory device of the present invention comprises a first wiring,
A second wiring that three-dimensionally intersects the first wiring;
It is electrically insulated from a wiring and electrically connected to the second wiring, and is formed by sandwiching a tunnel insulating layer between ferromagnetic layers in an intersecting region of the first wiring and the second wiring. A tunnel magnetic resistance device, comprising: a tunnel magnetoresistive element, for storing information by utilizing the fact that the resistance value changes depending on whether the spin directions of the ferromagnetic body are parallel or antiparallel. And a processing stop layer at at least one of the interfaces with the ferromagnetic layers sandwiching the tunnel insulating layer.

In the above magnetic memory device, like the tunnel magnetoresistive element described above, when processing the upper ferromagnetic material layer, it is not necessary to stop the processing in the tunnel insulating layer, and the upper ferromagnetic material layer is not processed. It is provided that the body layer can be processed up to the processing stop layer. for that reason,
The difficulty of processing the tunnel magnetoresistive element mounted on the magnetic memory device is reduced.

A method of manufacturing a magnetic memory device according to the present invention comprises a step of forming a first wiring and a tunnel magnetic layer electrically sandwiched between a ferromagnetic material layer and a tunnel insulating layer. A step of forming a resistance element; and a step of electrically connecting to the tunnel magnetoresistive element and forming a second wiring which three-dimensionally intersects the first wiring with the tunnel magnetoresistive element in between. In the method of manufacturing a non-volatile magnetic memory device, the tunnel magnetoresistive element manufacturing process includes a step of forming a first ferromagnetic layer and a step of forming a processing stop layer on the first ferromagnetic layer. A step of forming an opening at the bottom where the first ferromagnetic layer is exposed in the processing stop layer on the formation region of the tunnel magnetoresistive element, and a tunnel including the inside of the opening on the processing stop layer. Insulation layer, second strong magnetic A step of sequentially stacking a body layer and a cap layer from a lower layer, a step of processing from the cap layer to the tunnel insulating layer into a tunnel magnetoresistive element shape, and a step of covering the cap layer and the first ferromagnetic layer. Processing the processing stop layer and the first ferromagnetic material layer after forming the mask.

Alternatively, after the tunnel insulating layer is formed on the first ferromagnetic layer, the processing stop layer is formed, and an opening exposing the tunnel insulating layer at the bottom is formed, and then the second ferromagnetic layer is formed. The cap layers may be sequentially laminated. In this case, after processing the cap layer and the second ferromagnetic layer into the shape of the tunnel magnetoresistive element, the cap layer and the second ferromagnetic layer are formed.
A mask that covers the ferromagnetic layer is formed, and then the processing stop layer and the first ferromagnetic layer are processed.

In the method of manufacturing the magnetic memory device, as in the method of manufacturing the tunnel magnetoresistive element described above, when processing the upper ferromagnetic layer, it is necessary to stop the processing at the tunnel insulating layer. Then, the processing of the upper ferromagnetic layer is stopped at the processing stop layer. Therefore, the difficulty of processing the tunnel magnetoresistive element mounted on the magnetic memory device is reduced.

Further, since the cap layer and the second ferromagnetic material layer are covered with the mask, adhesion of a processed product for connecting the first ferromagnetic material layer and the cap layer or the second ferromagnetic material layer. Does not happen. Therefore, an unintended current path is not generated between the first and second ferromagnetic layers, and the problem of degrading the TMR element characteristics is solved.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The tunnel magnetoresistive element of the present invention (hereinafter referred to as TMR element, TMR stands for Tunnel Magneto R
Esistance) and an example of an embodiment relating to a manufacturing method thereof will be described with reference to manufacturing step sectional views of FIGS. 1 and 2, the magnetic memory device M
An example of the TMR element mounted on the RAM is shown. Note that the drawings are shown schematically.

First, although not shown, a CMOS transistor manufacturing technique is used to form a transistor (for example, an insulated gate field effect transistor to be a read transistor) on a substrate (for example, a semiconductor substrate), and then a first transistor covering it. An insulating film is formed. Further, after forming wirings (for example, sense lines), electrodes and the like on the first insulating film, a second insulating film covering them is formed. Further, as shown in (1) of FIG. 1, a word line (eg, write word line) 11 is formed on a second insulating film (not shown), and a third insulating film 43 is formed so as to cover the word line 11. Form.

PVD, for example, is formed on the third insulating film 43.
The antiferromagnetic material layer 301 is formed by the (Physical Vapor Deposition) method, and then the first ferromagnetic material layer 302 serving as the magnetization fixed layer is formed. Note that, usually, before forming the antiferromagnetic layer 301, for example, a barrier layer (not shown) made of titanium nitride, tantalum, or tantalum nitride is formed.

Next, the processing stop layer 21 is formed on the first ferromagnetic layer 302 by depositing, for example, silicon oxide to a thickness of 30 nm. The formation method is, for example, a chemical vapor deposition method, sputtering, or the like. After that, an etching mask (not shown) is formed by a resist by a known resist coating and lithographic technique, and by the etching technique using the etching mask, the processing stop layer 21 on the formation region of the TMR element is formed on the bottom of An opening 212 is formed to expose the 1 ferromagnetic layer 302. afterwards,
The resist used for this etching is removed. The side wall of the opening 212 is formed to be substantially vertical in the drawing, but it may be formed to be an inclined surface. When it is formed on the inclined surface, the coverage of the film in the subsequent film forming process becomes good. In particular, in the next step, it becomes easy to form a tunnel insulating layer that needs to be formed in an extremely thin film.

Then, as shown in FIG. 1B, the tunnel insulating layer 303, the second ferromagnetic layer 304, and the tunnel insulating layer 303 are formed on the processing stop layer 21 including the inside of the opening 212 by the PVD method, for example. The cap layer 305 is sequentially laminated from the lower layer.

The antiferromagnetic material layer 301 is made of, for example, iron.
One of manganese alloy, nickel manganese alloy, platinum manganese alloy, iridium manganese alloy, rhodium manganese alloy, cobalt oxide and nickel oxide
Use seeds. The antiferromagnetic layer 301 is used for the TMR element 1
It is also possible to serve as a conductive layer used for connection with the switching element connected in series with 3.

The first ferromagnetic layer 302 serves as a magnetization fixed layer, and is made of, for example, a ferromagnetic material made of nickel, iron or cobalt, or an alloy material containing at least two kinds of nickel, iron and cobalt. To use. The first ferromagnetic layer 302 is formed so as to be in contact with the antiferromagnetic layer 301, and the first ferromagnetic layer 302 and the antiferromagnetic layer 301 are exchanged with each other by an exchange interaction acting between the layers. 1
The ferromagnetic layer 302 has strong unidirectional magnetic anisotropy. That is, the magnetization direction of the first ferromagnetic layer 302 is pinned by the exchange coupling with the antiferromagnetic layer 301.
ning).

The first ferromagnetic layer 302 may have a structure in which magnetic layers are laminated with a conductive layer sandwiched therebetween. For example, a configuration may be adopted in which a ferromagnetic layer, a conductive layer in which a magnetic layer is antiferromagnetically coupled, and another ferromagnetic layer are sequentially stacked from the antiferromagnetic layer 301 side. The first ferromagnetic layer 302 may have a structure in which three or more ferromagnetic layers are stacked with a conductor layer interposed therebetween. For the conductor layer, for example, ruthenium, copper, chromium, gold, silver or the like can be used.

The tunnel insulating layer 303 cuts off the magnetic coupling between the second ferromagnetic layer 304 serving as a memory layer and the first ferromagnetic layer 302 serving as the magnetization fixed layer, and allows a tunnel current to flow. It has the function of. Therefore, although aluminum oxide having a thickness of 0.5 nm to 5 nm is usually used, for example, magnesium oxide, silicon oxide, aluminum nitride, magnesium nitride, silicon nitride, aluminum oxynitride, magnesium oxynitride, or silicon oxynitride is used. May be. Since the thickness of the tunnel insulating layer 303 is as thin as 0.5 nm to 5 nm as described above, it is formed by the ALD (Atomic Layer Deposition) method. Alternatively, it is formed by depositing a metal film such as aluminum by sputtering and then performing plasma oxidation or nitridation.

The second ferromagnetic layer 304 serves as a storage layer, and is, for example, nickel, iron or cobalt, or at least two of nickel, iron and cobalt.
A ferromagnet of an alloy material consisting of seeds is used. The direction of magnetization of the second ferromagnetic layer 304 can be changed to be parallel or antiparallel to the direction of the first ferromagnetic layer 302 serving as the lower fixed magnetization layer by an externally applied magnetic field.

The cap layer 305 has the functions of preventing mutual diffusion between a TMR element and a wiring connecting another TMR element, reducing contact resistance, and preventing oxidation of the first ferromagnetic layer 304 serving as a memory layer. Usually copper, tantalum nitride,
It is made of a material such as tantalum or titanium nitride.

Although the processing stop layer 21 is formed of a silicon oxide film, it is an oxide film type insulating film such as an aluminum oxide film, a nitride film type insulating film such as a silicon nitride film, or a silicon oxynitride film. It is also possible to form it with an oxynitride film type insulating film such as.

Then, an etching mask 51 for forming a TMR element with a resist is formed by known resist coating and lithographic techniques.

Next, the cap layer 305 to the tunnel insulating layer 303 are etched or ion milled by the etching technique using the etching mask 51. After that, the processed product attached to the resist mask and the processed side wall is peeled off. In this etching, as an example, an inductively coupled etching apparatus was used, and the etching conditions were as follows. Chlorine gas is used as the source gas and the supply flow rate is 60 cm ³ / min
(Standard state), chamber pressure 0.5Pa, substrate temperature 70 ° C, upper RF power 250W, lower RF
The power was set to 150W. This etching condition is an example, and can be appropriately changed within the range suitable for the above etching process.

As a result, as shown in FIG. 1C, the cap layer 305 to the tunnel insulating layer 303 are processed into the shape of the TMR element. At this time, the etching (or ion milling) is stopped by the processing stop layer 21. In addition, even if a conductive processed product is generated during this etching, the first ferromagnetic layer 302 is covered with the processing stop layer 21, the cap layer 305, etc., so that the first ferromagnetic layer 302 is formed. No processing organisms adhere to the surface.

Next, as shown in FIG. 1D, a mask 53 that covers the processed cap layer 305 and the second ferromagnetic layer 304 is formed. The mask 53 is formed as follows. After depositing silicon oxide to a thickness of 30 nm by, for example, a chemical vapor deposition method, a resist mask (not shown) is formed by resist coating and a lithography technique. After that, the silicon oxide film is formed by an etching technique using a resist mask. At that time, the processing stop layer 21 made of silicon oxide is also etched. This etching is performed by the cap layer 305 and the second ferromagnetic layer 3 described above.
The same etching apparatus and etching conditions as those for 04 can be used.

After removing the resist mask,
As shown in (5) of FIG. 2, using the mask 53,
The first ferromagnetic layer 302 and the antiferromagnetic layer 301 are processed. In this way, the TMR element 13 having the structure in which the tunnel insulating layer 303 is sandwiched between the first ferromagnetic layer 302 and the second ferromagnetic layer 304 is formed.

As described above, the TMR element 13 of the present invention includes the tunnel insulating layer 303 as the first and second ferromagnetic layers 302, 3
The tunnel insulating layer 303
And the processing stop layer 21 at least at one of the interfaces with the first and second ferromagnetic layers 302 and 304 sandwiching the tunnel insulating layer 303 and around the formation region of the TMR element 13. .

After that, as shown in (6) of FIG.
A silicon-based fourth insulating film 44, for example, silicon oxide having a thickness of 100 nm is formed on the insulating film 43 so as to cover the TMR element 13.
It is deposited and formed to a thickness of. At this time, the mask 53 is left as it is because it is made of silicon oxide which is an insulating film. Then, the surface of the fourth insulating film 44 is polished by chemical mechanical polishing to flatten the surface. that time,
As illustrated, the surface of the mask 53 may be exposed and the surface of the mask 53 may be flattened together.

An etching mask (not shown) for forming a connection layer with the bit line is formed of a resist by a known resist coating and lithographic technique, and the etching technique using the etching mask is used to form a line (7) in FIG. ), A connection hole 441 is formed in the mask 53 and the surface of the cap layer 305 of the TMR element 13 is exposed at the bottom thereof. When the fourth insulating film 44 is formed on the mask 53, the connection hole 44 is also formed in the fourth insulating film 44.
1 is formed. Then, the resist is removed.

Next, as shown in (8) of FIG. 2, a conductive film for forming a bit line is formed on the fourth insulating film 44 (including the mask 53) including the connection hole 441. After that, a resist mask (not shown) for forming a bit line is formed by ordinary resist coating and lithographic techniques, and then a conductive layer is processed by an etching technique using the resist mask, and the TMR element is formed through the connection hole 441. The bit line 12 connected to the cap layer 305 of 13 is formed so as to cross three-dimensionally (for example, orthogonally) to the word line 11 with the TMR element 13 in between. After that, the etching mask used for this etching is removed. FIG. 2 (8) shows the state after removing the etching mask.

In the embodiment described above, the processing stop layer 21 is formed on the first ferromagnetic layer 302, but the processing stop layer 21 is formed after the tunnel insulating layer 303 is formed on the first ferromagnetic layer 302. 21 may be formed. In this case,
An opening 142 is formed in the processing stop layer 21 so that the tunnel insulating layer 303 is exposed at the bottom. Then the opening 1
The second ferromagnetic layer 30 on the processing stop layer 21 including 42.
4. The cap layer 305 is sequentially laminated. Then, a resist mask is formed by resist coating and a lithography technique, and etching or ion milling is performed using the resist mask to process the cap layer 305 and the second ferromagnetic layer 304 into the shape of the tunnel magnetoresistive element. Then, the cap layer 305 and the second ferromagnetic layer 3
After forming the mask 53 covering 04, the processing stop layer 21, the first ferromagnetic layer 142 and the antiferromagnetic layer 301.
It is also possible to complete the TMR element 13 by processing.

In the method of manufacturing the TMR element 13 described above, at least one of the interfaces between the tunnel insulating layer 303 and the first and second ferromagnetic layers 302 and 304 sandwiching the tunnel insulating layer 303, and the TMR element. Since the processing stop layer 21 is provided around the formation region of the TMR element 13,
It is not necessary to stop the processing of the tunnel insulating layer 303 formed of an ultrathin film having a film thickness of about 0.5 nm to 5 nm when processing the second ferromagnetic layer 304 for forming The processing of the magnetic layer 304 is stopped at the processing stop layer 21. Therefore, the difficulty of processing is reduced.

After forming the mask 53 that covers the cap layer 305 and the second ferromagnetic layer 304, the processing stop layer 21 to the first ferromagnetic layer 302 and the antiferromagnetic layer 30 are formed.
Since 1 to 1 is processed, even if a processed product having conductivity is generated during processing, the cap layer 305 is processed.
Since the second ferromagnetic layer 304 and the second ferromagnetic layer 304 are covered with the mask 53, adhesion of a processed product that connects the first ferromagnetic layer 302 and the cap layer 305 or the second ferromagnetic layer 304 does not occur. Absent. Therefore, an unintended current path is not generated between the first and second ferromagnetic layers 302 and 304, and the problem of deteriorating the characteristics of the TMR element 13 is solved.

In the embodiment of the method for manufacturing the TMR element, when the cap layer 305 is formed, the recesses formed on the surface of the underlying second ferromagnetic material layer 304 are buried to form the second ferromagnetic material. If a sufficient film thickness that functions as a cap layer is formed on the layer 304, the surface of the cap layer 305 is exposed when the surface of the fourth insulating film 44 is planarized, and the fourth insulating film is formed on the cap layer 305. The surface of the cap layer 305 can be flattened together with the fourth insulating film 44 so that the film 44, the mask 53, and the like do not remain. For example,
In the case of the manufacturing method described in the above embodiment, the cap layer 305 has a thickness of 100 nm to 250 nm, preferably 1 nm or more.
It may be formed in a film thickness of 50 nm or more and 250 nm or less.
In this case, since it is not necessary to form the connection hole 431 for connecting the bit line to the TMR element 13, it is possible to omit the lithography process and the etching process for forming the connection hole 441. That is, since the number of steps can be reduced, the manufacturing cost can be reduced.

Further, in the TMR element 13, the tunnel insulating layer 303 and at least one of the interfaces between the tunnel insulating layer 303 and the first and second ferromagnetic layers 302 and 304, and the TMR element 13 is provided. Since the processing stop layer 21 is provided around the formation region of, the second ferromagnetic layer 304 forming the TMR element 13 is formed of an extremely thin film with a thickness of about 0.5 nm to 5 nm. It is not necessary to stop the processing of the tunnel insulating layer 303, and the processing of the second ferromagnetic layer 304 can be performed up to the processing stop layer 21. for that reason,
The difficulty of processing is reduced.

Next, as an example of the magnetic memory device of the present invention, an MRAM (Magnetic Random Access Memory) is shown in FIG.
~ It demonstrates by FIG.

FIG. 3 is a schematic perspective view showing a simplified main part of the MRAM, and the read circuit portion and the connection circuit portion between the read circuit portion and the magnetoresistive effect element are not shown. As shown in FIG. 3, write word lines 11 (1
11, 112, 113) and the bit line 12 (121,
122, 123). An insulating film (not shown) is formed between the write word line 11 and the bit line 12, and an insulating film (not shown) is formed between the write word line 11 and the bit line 12, and the magnetoresistive effect (TMR) element 13 is connected to the bit line. (1
31-139) are arranged. Writing to the TMR element 13 is performed by the bit line 12 and the write word line 11
The second ferromagnetic layer 30 serving as a storage layer of the TMR element 13 formed in the intersection region between the bit line 12 and the write word line 11 by a synthetic magnetic field generated by applying a current to the second ferromagnetic layer 30.
The first ferromagnetic layer 302 having the magnetization direction of No. 4 as the magnetization fixed layer
Parallel or anti-parallel to. As described with reference to (5) of FIG. 2, the TMR element 13 has the processing stop layer 21 formed around the interface between the first ferromagnetic layer 302 and the tunnel insulating layer 303. Further, the drawing shows a part (9) of memory cells of the MRAM, and the required number of memory cells can be integrated.

Although the processing stop layer 21 is formed around the interface between the first ferromagnetic layer 302 and the tunnel insulating layer 303 in FIG. 3, the interface between the second ferromagnetic layer 304 and the tunnel insulating layer 303 is formed. The processing stop layer 21 may be formed around the.

The asteroid curve shown in FIG. 4 shows the reversal threshold value of the magnetization direction of the storage layer due to the applied easy-axis direction magnetic field H _EA and hard-axis direction magnetic field H _HA . When a synthetic magnetic field vector corresponding to the outside of the asteroid curve is generated, magnetic field reversal occurs. The resultant magnetic field vector inside the asteroid curve does not invert the cell from one of its current bistable states. In addition, since the magnetic field generated by the word line or the bit line alone is applied to cells other than the intersection of the word line and the bit line that are passing current, when the magnitude of these is greater than or equal to the one-way reversal magnetic field H _K. Since the magnetization directions of the cells other than the intersections are also inverted, the selected cell can be selectively written only when the combined magnetic field is in the shaded portion 401.

As described above, in the MRAM array, the memory cells are arranged at the intersections of the grids formed by the bit lines and the write word lines. In the case of the MRAM, by using the write word line and the bit line, the asteroid magnetization reversal characteristic can be utilized to selectively write in the individual memory cells.

The combined magnetization in a single storage area is the easy-axis direction magnetic field H _EA and the hard-axis direction magnetic field H applied to it.
Determined by vector composition with _HA . The current flowing through the bit line applies a magnetic field (H _EA ) in the easy axis direction to the cell,
A current flowing through the write word line applies a magnetic field (H _HA ) in the hard axis direction to the cell.

Next, the MRAM described with reference to FIG.
The circuit will be described with reference to the circuit diagram of FIG.

As shown in FIG. 5, the MRAM circuit includes six memory cells, and the write word lines 11 (111, 112) and bit lines 12 (121, 122) corresponding to FIG. , 123). In the intersection area of the write line word line 11 and the bit line 12, the TMR element 13 (131, 1;
32, 134, 135, 137, and 138 are arranged, and element selection is performed at the time of reading. The field effect transistors 141, 142, and 14 correspond to each memory element.
4, 145, 147 and 148 are connected. Further, a sense line 151 is connected to the field effect transistors 141, 144, 147, and the field effect transistor 142,
A sense line 152 is connected to 145 and 148.

The sense line 151 is the sense amplifier 153.
, And the sense line 152 is connected to the sense amplifier 154 to detect the information stored in each element. Bidirectional write word line current drive circuits 161 and 162 are connected to both ends of the write word line 111,
Bidirectional write word line current drive circuits 163 and 164 are connected to both ends of the write word line 112. Further, a bit line current drive circuit 171 is connected to one end of the bit line 121, a bit line current drive circuit 172 is connected to one end of the bit line 122, and a bit line current drive circuit 173 is connected to one end of the bit line 123. Has been done.

In the above MRAM, the tunnel insulating layer 303
Since the processing stop layer 21 is provided on at least one of the interfaces with the first and second ferromagnetic layers 302 and 304 sandwiching the tunnel insulating layer 303 and around the formation region of the TMR element 13, Second forming the TMR element 13
When the ferromagnetic layer 304 is processed (for example, etched or ion milled), the tunnel insulating layer 303 is formed of an extremely thin film having a thickness of about 0.5 nm to 5 nm.
Therefore, it is not necessary to stop the processing, so that the processing of the second ferromagnetic layer 304 can be performed up to the processing stop layer 21. Therefore, the difficulty of processing the TMR element 13 mounted on the MRAM is reduced.

Next, the magnetic memory device (MRA of the present invention
The manufacturing method of M) is characterized in that the TMR element is formed by the process described with reference to FIGS. 1 and 2 in the conventionally known manufacturing method.

Therefore, in the method of manufacturing the magnetic memory device of the present invention, similarly to the method of manufacturing the tunnel magnetic TMR element described with reference to FIGS. 1 and 2, the second ferromagnetic layer 304 is processed, for example, etched or When performing the ion milling process, it is not necessary to stop the process on the tunnel insulating layer 303, and the process on the second ferromagnetic layer 304 is stopped on the process stop layer 21. Therefore, the difficulty of processing the tunnel magnetoresistive element mounted in the magnetic memory device is reduced.

In addition, the processed cap layer 305 and the second
Since the processing stop layer 21 to the first ferromagnetic layer 304 are processed after the ferromagnetic layer 304 and the mask 53 are covered with the mask 53, even if a processed product having conductivity is generated during processing, 1. Ferromagnetic material layer 302 and cap layer 30
5 or the adhesion of the processed product to connect the second ferromagnetic layer 304 does not occur. Therefore, an unintended current path is not generated between the first and second ferromagnetic layers 302 and 304, and the problem of degrading the characteristics of the TMR element 13 and reducing the reliability of the MRAM is solved. .

In the method of manufacturing the MRAM, the processing stop layer 21 may be formed after forming the tunnel insulating layer 303 on the first ferromagnetic layer 302. In this case, the opening 142 is formed in the processing stop layer 21 so that the tunnel insulating layer 303 is exposed at the bottom. After that, the opening 14
A second ferromagnetic layer 304 on the processing stop layer 21 containing 2;
The cap layer 305 is sequentially laminated. Then, a resist mask is formed by resist coating and a lithography technique, and etching or ion milling is performed using the resist mask to process the cap layer 305 and the second ferromagnetic layer 304 into the shape of the TMR element 13. afterwards,
After forming the mask 53 covering the cap layer 305 and the second ferromagnetic layer 304, the TMR element 13 is formed by processing the processing stop layer 21, the first ferromagnetic layer 142 and the antiferromagnetic layer 301. It is also possible to do so.

In the description of the above embodiment, the MRAM including one selection element and one TMR element (1T1J structure) has been described. However, a generally known cross point type MRA is used.
The present invention can also be applied to M. In the cross-point type MRAM, a tunnel insulating layer is sandwiched between ferromagnetic write layers between write word lines and bit lines that intersect three-dimensionally (for example, at right angles), and one ferromagnetic layer is antiferromagnetic. This can be realized by providing a TMR element to which the body layer is connected and a pn junction diode formed by connecting the n layer to the antiferromagnetic material layer side. The connection between the TMR element and the bit line is the same as in the MRAM having the 1T1J structure described with reference to FIGS. 1 to 3, and the TMR element and the write word line are connected via a pn junction diode.

In the manufacturing method applied to the cross-point type MRAM, after forming the write word line, the pn junction diode is formed so that the p layer is connected to the write word line. Note that after forming the write word line, an insulating film covering the write word line may be formed once, and then the surface of the insulating film may be planarized and the write word line surface may be exposed.

Next, after forming an insulating film covering the pn junction diode, the surface of the insulating film is flattened and the surface of the pn junction diode is exposed. After that,
The steps after the step of forming the antiferromagnetic layer 301 described with reference to FIG. 2 may be performed.

Alternatively, after forming the write word line and further forming the insulating film covering the write word line, the surface of the insulating film is flattened so that the surface of the write word line is exposed. Then, a pn for forming a pn junction diode
After forming the p-layer and the n-layer of the bonding layer in this order, the steps after the step of forming the antiferromagnetic material layer 301 described with reference to FIG. When processing the ferromagnetic layer 301, the pn junction layer may be processed to form a pn diode. The subsequent steps are the same as the steps after (6) in FIG.

[0075]

As described above, according to the tunnel magnetic TMR element of the present invention, at least one of the interfaces with the ferromagnetic layers sandwiching the tunnel insulating layer and in the formation region of the tunnel magnetoresistive element. Since the processing stop layer is provided in the periphery, it is not necessary to stop the processing of the upper ferromagnetic layer at the tunnel insulating layer, and the processing stop layer can be performed. Therefore, it is possible to provide a configuration that reduces the processing difficulty. it can.

According to the method of manufacturing a tunnel magnetic TMR element of the present invention, at least one of the interfaces with the first and second ferromagnetic layers sandwiching the tunnel insulating layer and in the formation region of the tunnel magnetoresistive element. Since the processing stop layer is provided in the periphery, it is not necessary to stop the processing of the second ferromagnetic layer in the tunnel insulating layer, and the processing can be stopped in the processing stop layer. Therefore, the difficulty of processing can be reduced. Further, since the processing can be surely stopped in the processing stop layer, the processing accuracy can be improved.

Furthermore, since a mask covering the cap layer and the second ferromagnetic material layer is formed and the processing from the processing stop layer to the first ferromagnetic material layer is processed, a processed product having conductivity even during processing is obtained. Even if it occurs, it is possible to prevent the adhesion of the processed product that connects the first ferromagnetic layer and the cap layer or the second ferromagnetic layer. Therefore, the first,
An unintended current path is not generated between the second ferromagnetic layers, and the problem of degrading the TMR element characteristics can be solved.

According to the magnetic memory device of the present invention, the same effect as that of the tunnel magnetic TMR element described above can be obtained, so that the tunnel magnetoresistive element with reduced processing difficulty can be mounted in the magnetic memory device. . Therefore, this magnetic memory device can be used as a non-volatile memory for information communication equipment, particularly small personal equipment such as a mobile terminal.

According to the method of manufacturing the magnetic memory device of the present invention, the same effect as that of the method of manufacturing the tunnel magnetic TMR element described above can be obtained. A resistance element can be formed. Therefore, the manufacturing of the tunnel magnetoresistive element in the manufacturing method of the magnetic memory device becomes easy. Further, since adhesion of a processed product that connects the first ferromagnetic layer and the cap layer or the second ferromagnetic layer of the tunnel magnetoresistive element can be prevented, the first and second ferromagnetic layers No unintended current path is generated in the
The problem of degrading device characteristics is solved. Therefore, a highly reliable tunnel magnetoresistive element can be formed, and the reliability of the magnetic memory device can be improved.

[Brief description of drawings]

FIG. 1 is a manufacturing step sectional view illustrating an embodiment of a method for manufacturing a tunnel magnetoresistive element of the present invention.

FIG. 2 is a manufacturing step sectional view illustrating the embodiment of the method for manufacturing the tunnel magnetoresistive element of the present invention.

FIG. 3 is a schematic perspective view showing a simplified configuration of a main part of an MRAM for explaining an embodiment of a magnetic memory device of the present invention.

[FIG. 4] Easy axis magnetic field H _EA and hard axis magnetic field H
₃ is an asteroid curve showing the reversal threshold of the magnetization direction of the memory layer by _HA .

FIG. 5 is a circuit diagram showing an example of a circuit configuration of an MRAM.

FIG. 6 is a manufacturing step cross-sectional view illustrating a method for manufacturing a conventional tunnel magnetoresistive element.

[Explanation of symbols]

13 ... TMR element, 21 ... Processing stop layer, 302 ... First ferromagnetic layer, 303 ... Tunnel insulating layer, 304 ... Second ferromagnetic layer

Claims (6)

[Claims] 1. A tunnel magnetoresistive element constituted by sandwiching a tunnel insulating layer between ferromagnetic layers, wherein at least one of an interface between the tunnel insulating layer and a ferromagnetic layer sandwiching the tunnel insulating layer is provided. And a tunnel magnetoresistive element having a processing stop layer around a region where the tunnel magnetoresistive element is formed. 2. A step of forming a first ferromagnetic material layer, the method comprising: forming a processing stop layer on the first ferromagnetic material layer; and forming a bottom portion on the processing stop layer on a tunnel magnetoresistive element formation region. A step of forming an opening exposing the first ferromagnetic layer in the layer, and a tunnel insulating layer, a second ferromagnetic layer, and a cap layer sequentially stacked from the lower layer on the processing stop layer including the inside of the opening. And a step of processing from the cap layer to the tunnel insulating layer into a shape of a tunnel magnetoresistive element, and the processing stop layer after forming a mask covering the cap layer and the second ferromagnetic layer. And a step of processing the first ferromagnetic layer, the method for manufacturing a tunnel magnetoresistive element. 3. A step of forming a first ferromagnetic layer, a step of forming a tunnel insulating layer on the first ferromagnetic layer, a step of forming a processing stop layer on the tunnel insulating layer, and a tunnel. A step of forming an opening at the bottom where the tunnel insulating layer is exposed in the processing stop layer on the formation region of the magnetoresistive element; and a second ferromagnetic layer on the processing stop layer including the inside of the opening. A step of sequentially stacking a cap layer from a lower layer, a step of processing the cap layer and the second ferromagnetic layer into a tunnel magnetoresistive element shape, and a step of covering the cap layer and the second ferromagnetic layer. And a step of processing from the processing stop layer to the first ferromagnetic layer after forming the mask for forming the tunnel magnetoresistive element. 4. A first wiring, a second wiring that three-dimensionally intersects with the first wiring, a wiring electrically insulated from the first wiring, and electrically connected to the second wiring, A tunnel magnetoresistive element having a tunnel insulating layer sandwiched between ferromagnetic layers is provided in an intersecting region of the first wiring and the second wiring, wherein spin directions of the ferromagnetic bodies are parallel or antiparallel. In a non-volatile magnetic memory device that stores information by utilizing a change in resistance value depending on parallelism, processing is performed on at least one of an interface between the tunnel insulating layer and a ferromagnetic layer sandwiching the tunnel insulating layer. A magnetic memory device having a stop layer. 5. A step of forming a first wiring, a step of forming a tunnel magnetoresistive element electrically insulated from the first wiring by sandwiching a tunnel insulating layer between ferromagnetic layers, And a step of forming a second wiring electrically connected to the tunnel magnetoresistive element and interposing the tunnel magnetoresistive element therebetween and three-dimensionally intersecting the first wiring. In the method, the step of manufacturing the tunnel magnetoresistive element includes a step of forming a first ferromagnetic layer, and a step of forming a processing stop layer on the first ferromagnetic layer, and then forming a tunnel magnetoresistive element on a formation region. A step of forming an opening at the bottom of which the first ferromagnetic layer is exposed in the processing stop layer, and a tunnel insulating layer and a second ferromagnetic layer on the processing stop layer including the inside of the opening. And the cap layer from below A step of sequentially laminating, a step of processing from the cap layer to the tunnel insulating layer into a shape of a tunnel magnetoresistive element, and a step of forming a mask for covering the cap layer and the second ferromagnetic layer And a step of processing the stop layer and the first ferromagnetic layer. 6. A step of forming a first wiring, a step of forming a tunnel magnetoresistive element electrically insulated from the first wiring by sandwiching a tunnel insulating layer between ferromagnetic layers, And a step of forming a second wiring electrically connected to the tunnel magnetoresistive element and interposing the tunnel magnetoresistive element therebetween and three-dimensionally intersecting the first wiring. In the method, the step of manufacturing the tunnel magnetoresistive element includes a step of forming a first ferromagnetic layer, a step of forming a tunnel insulating layer on the first ferromagnetic layer, and a step of processing on the tunnel insulating layer. After forming the stop layer, a step of forming an opening at the bottom where the tunnel insulating layer is exposed, in the processing stop layer on the formation region of the tunnel magnetoresistive element, and including the inside of the opening on the processing stop layer. To 2 a step of sequentially stacking a ferromagnetic layer and a cap layer from a lower layer; a step of processing the cap layer and the second ferromagnetic layer into a tunnel magnetoresistive element shape; the cap layer and the second strong layer; And a step of processing the processing stop layer to the first ferromagnetic material layer after forming a mask that covers the magnetic material layer.