JP2011040496A - Method of manufacturing magnetic medium, and sputtering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method that suppresses variations of memory characteristics of MRAM among finished products of MARM using TMR element in mass production, which leads to high defective occurrence frequency, wherein the variations are resulted from that the RM ratio of the TMR element in mass production is varied among wafer products without being maintained at a constant value. <P>SOLUTION: The method includes the steps of forming a ferromagnetic film in an amorphous state by DC-sputtering a ferromagnetic target under application of DC power in which high frequency component is cut by a high frequency component cut filter, and forming a crystalline magnesium oxide film by high-frequency sputtering a magnesium oxide target. The film formation sputtering device 200 includes a control program which executes the steps. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic medium used in a magnetic reproducing head of a magnetic disk drive, a storage element (MRAM) of a magnetic random access memory, and a magnetic sensor, preferably a tunnel magnetoresistive element (more preferably a spin valve type tunnel magnetoresistive). The present invention relates to a film forming sputtering apparatus provided with a magnetic medium represented by an element) and a storage medium.

  Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, Non-Patent Document 4, and Non-Patent Document 5 are tunneled with a crystalline magnesium oxide film. A tunneling magnetoresistance effect element (hereinafter also referred to as a TMR element) used as a barrier film is described.

JP 2003-318465 A International Publication Number WO2005 / 088745 JP 2006-080116 A US 2006/0056115 publication

D. D. “Applied Physics Letters”, 86,092502 (2005) by Djayapraira et al. C. L. Platt et al., “J. Appl. Phys.” 81 (8), 15 April 1997. W. H. Butler et al., “The American Physical Society” (Physical Review Vol. 63, 0544416) 8, January 2001. "Japan Journal of Applied Physics" by Shinji Yuasa et al., Vol. 43, no. 48, pp 588-590, issued April 2, 2004 S. P. Published by Parkin et al., "2004 Nature Publishing Group" Letters, pp 862-887, published October 31, 2004.

  The technical problem of the present invention is that the performance of various products (for example, MRAM memory characteristics, etc.) among various products (for example, MARM, magnetic head, magnetic disk, etc.) using TMR elements during mass production. There was variation and the frequency of defective products was high. This performance variation is due to the fact that the MR ratio of the TMR element during mass production was not maintained at a constant value between the finished products (between each finished product in which the TMR elements were formed for each wafer substrate) and fluctuated. Was.

  In the present invention, firstly, a ferromagnetic thin film amorphous film is formed by DC magnetron sputtering of a target having a ferromagnetic material under application of DC power with a high frequency component cut by a high frequency component cut filter, and then oxidized. A method of manufacturing a magnetic medium having a step of forming a magnesium oxide thin film crystal by subjecting a magnesium-containing target to high-frequency magnetron sputtering under application of a high-frequency power, and a control for executing the step during operation. It is a film-forming patching apparatus provided with a storage medium storing a program.

  The present invention secondly forms a first ferromagnetic film in an amorphous state by DC magnetron sputtering of a target having a first ferromagnetic material under application of DC power with high frequency components cut by a high frequency component cut filter. A first step of film formation, and after the first step, a crystalline magnesium oxide film is formed by magnetron sputtering a target having magnesium oxide under application of high-frequency power with low-frequency component cut by a low-frequency component cut filter. The second step of film formation, after the second step, the target having the second ferromagnet is applied by DC magnetron sputtering under the application of DC power whose high-frequency component is cut by the high-frequency component cut filter. Third step of forming a ferromagnetic film, and after the third step The magnesium oxide film, the amorphous first ferromagnetic film, and the amorphous second ferromagnetic film are subjected to annealing, thereby causing a phase change from the amorphous state to the crystalline state. This is a method of manufacturing a magnetic medium for forming a tunnel magnetoresistive effect element using a process, and a film forming sputtering apparatus provided with a storage medium storing a control program for executing the process when the operation is executed.

  In mass production of a magnetic medium (for example, MRAM) including a TMR element, a high frequency component (for example, radio frequency) is used in a DC (direct current) sputtering method used for forming a ferromagnetic film used for a magnetization free layer and a magnetization fixed layer. When using a DC magnetron sputtering apparatus of a DC power source including a (RF) frequency to a microwave of 3 GHz, but not limited to this range, a frequency of 5000 KHz below the radio frequency to a high frequency including a radio frequency component) In some cases, a defective magnetic medium (for example, an MR ratio of 80%) having a predetermined MR ratio (for example, an MR ratio of 120% or more) or less is frequently produced. For this reason, the manufacturing cost at the time of mass production of finished products such as MRAM, magnetic head and magnetic disk has been high.

According to the knowledge of the present inventor, the above phenomenon is caused when the high frequency component is present in the direct current (DC) power source, the magnetic field lines of the cathode magnet mounted on the DC magnetron sputtering apparatus and the density distribution of the plasma are high frequency. Under the influence of the components, it was not stably maintained, causing unstable magnetic field lines and plasma paths. In particular, the magnetic field lines and plasma clouds that appear on the substrate-side surface of the ferromagnetic target mounted on the magnetron sputtering apparatus cause periodic positional fluctuations. As a result, the amount of sputtered particles made of ferromagnetic material deposited on the substrate is reduced. It was caused by periodic fluctuations.
According to the knowledge of the present inventor, when the amorphous ferromagnetic film is formed, the above-mentioned cause can be eliminated by cutting the high-frequency component from the DC power source.

  According to the present invention, performance variation (memory characteristics of MRAM, magnetic disk, etc., head sensor sensitivity, etc.) between finished products is effective when mass-producing finished products such as MRAM, heads and magnetic heads using TMR elements. As a result, the defective rate of the finished product can be greatly reduced, and mass production at low cost is possible.

It is sectional drawing of the magnetoresistive element of this invention. It is a schematic diagram of the manufacturing apparatus for the magnetoresistive element of this invention. It is a block diagram of this invention apparatus. It is a model perspective view of MRAM of this invention. It is an equivalent circuit diagram of MRAM of this invention. It is a model perspective view of the columnar crystal structure used by this invention. It is a magnetron high frequency sputtering device of the present invention. It is a magnetron DC sputtering apparatus of this invention.

  The magnesium oxide crystal layer used in the TMR element of the present invention has a crystal structure formed by an aggregate of columnar crystals (or needle crystals, columnar crystals, etc.). A structure of a crystal-amorphous mixed region including a partial amorphous region in the crystal region is also included in the concept of the present invention. This crystal layer is preferably in a crystalline state in which the (001) crystal plane is composed of a columnar single crystal aggregate of single crystals in the film thickness direction from one critical plane to the other critical plane (the columnar single crystal and 1 unit column is in a single crystal state).

  The average diameter of the columnar single crystal of magnesium oxide used in the present invention is 10 nm or less, preferably in the range of 2 nm to 5 nm, and the film thickness is 10 nm or less, preferably 0. It is in the range of 5 nm to 5 nm.

  In the present invention, a columnar single crystal magnesium oxide boron layer and a columnar single crystal zinc magnesium oxide layer can be used instead of the crystalline magnesium oxide layer.

  The ferromagnetic metal thin film (first ferromagnetic layer and second ferromagnetic layer) used in the present invention is preferably Co (cobalt) Fe (iron) B (boron) alloy, Co (cobalt) Fe (iron). ) Alloy, Co (cobalt) Fe (iron) Ni (nickel) alloy, Co (cobalt) Fe (iron) Ni (nickel) B (boron) alloy and at least one alloy group consisting of NiFe (nickel iron) alloy You can choose. The ferromagnetic metal thin films (first ferromagnetic film and second ferromagnetic film) used in the present invention are formed in an amorphous state. The first and second ferromagnetic films in the amorphous state are phase-changed into a crystal structure, for example, a crystal structure formed by an aggregate of columnar crystals (or including acicular crystals, columnar crystals, etc.) by an annealing process. Make a change. At this time, a structure of a crystal-amorphous mixed region including a partial amorphous region in the crystal region is also included in the concept of the present invention.

The amorphous state used in the present invention includes a nanocrystalline state (a state in which the lattice interval is 1.0 nm or less, preferably 0.5 nm or less and the lattice arrangement has regularity). The columnar crystal of the ferromagnetic metal thin film (first ferromagnetic film and second ferromagnetic film) used in the present invention has a (001) crystal plane preferentially oriented in the film thickness direction for each column. A single crystal is preferable. The average diameter of the columnar single crystal used in the present invention is 10 nm or less, preferably in the range of 2 nm to 5 nm, and the film thickness is 10 nm or less, preferably 0.5 nm to 5 nm. It is a range.
The ferromagnetic metal thin film used in the present invention was selected from a thin film containing at least one metal selected from the metal group consisting of Fe, Co, and Ni, particularly, the metal group consisting of Fe, Co, and Ni. A thin film containing at least one metal and B. The B atom in this case has a content of 30 atomic% or less, preferably 0.01 atomic% to 20 atomic% in the alloy.

The DC sputtering apparatus used in the sputtering apparatus of the present invention uses a high-pass filter connected to a DC power source, and this high-pass filter uses a high-frequency component (for example, a radio frequency (RF) frequency to 3 GHz) from the DC power of the DC power source. However, the present invention is not limited to this range, and may be a high frequency in the range of 5000 KHz to a radio frequency equal to or lower than the radio frequency.) The component can be cut.
In addition, the high-frequency sputtering apparatus used in the sputtering apparatus of the present invention uses a low-pass filter connected to a high-frequency power source, and this low-pass filter uses a high-frequency power of the high-frequency power source to a low frequency (a range of 5000 KHz or less, preferably 10 KHz). The low frequency component in the range of ˜3000 KHz can be cut.
The input power of the direct current power source and the high frequency power source is 100 watts to 3000 watts, preferably 200 watts to 2000 watts.

   DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

   FIG. 1 shows an example of a laminated structure of a magnetic medium 10 according to the present invention, and shows a laminated structure of a magnetic medium 10 using a tunnel magnetoresistive effect element (TMR element) 12. According to the magnetic medium 10, a TMR element 12 is used on a substrate 11, and for example, a multilayer film including nine layers including the TMR element 12 is formed. This nine-layered multilayer film has a multilayered film structure from the lowermost first layer “Ta (tantalum)” to the uppermost ninth layer “Ru (ruthenium)”.

As shown in FIG. 1, “PtMn (15)”, “CoFe (2.5)”, nonmagnetic “Ru (0.85)”, “CoFeB (3)”, nonmagnetic “MgO (1) .5) "," CoFeB (3) ", nonmagnetic" Ta (10) ", and nonmagnetic" Ru (7) "are laminated in this order.
Reference numeral 11 denotes a substrate such as a wafer substrate, a glass substrate, or a sapphire substrate. A TMR element 12 includes a first ferromagnetic film 121, a tunnel barrier layer 122, and a second ferromagnetic film 123.
Reference numeral 13 denotes a lower electrode layer (underlayer) of the first layer (Ta: tantalum layer), and reference numeral 14 denotes an antiferromagnetic film of the second layer (PtMn layer). 15 is a ferromagnetic film of the third layer (CoFe film), 16 is a nonmagnetic film for exchange coupling of the fourth layer (Ru layer), and 121 is a ferromagnetic film of the fifth layer (crystalline CoFeB). Thus, the layer composed of the third layer, the fourth layer, and the fifth layer is a magnetization fixed layer 19.
The substantial magnetization fixed layer 19 is a ferromagnetic film 121 made of the fifth crystalline CoFeB layer, and corresponds to the first ferromagnetic film.
Reference numeral 122 denotes a tunnel barrier layer of a sixth layer (MgO: crystalline magnesium oxide), which is an insulating layer. The tunnel barrier layer 122 used in the present invention may be a single crystalline magnesium oxide layer.

FIG. 6 is a schematic perspective view of a crystal structure 61 including an aggregate of columnar crystals 62 of MgO (magnesium oxide).
The columnar crystal 62 is a concept including a concept such as a needle crystal or a columnar crystal. Further, a structure of a crystal-amorphous mixed region including a partial amorphous region between the aggregates 61 of the columnar crystals 62 may be part of the polycrystalline region.
The columnar crystal of magnesium oxide used in the present invention is preferably a single crystal in which (001) crystal planes are preferentially oriented in the film thickness direction for each column. In other words, the column unit crystal is a single crystal (columnar single crystal).
The average diameter of the columnar single crystal of magnesium oxide used in the present invention is 10 nm or less, preferably in the range of 2 nm to 5 nm, and the film thickness is 10 nm or less, preferably 0. It is in the range of 5 nm to 5 nm.

Reference numeral 123 denotes a seventh layer (CoFeB) crystalline ferromagnetic film, which is a magnetization free layer, and corresponds to a second ferromagnetic film.
In addition to the above, the seventh layer 123 may be a crystalline ferromagnetic film using crystalline NiFe (nickel iron alloy) composed of an aggregate of columnar crystal groups.
The crystalline ferromagnetic films 121 and 123 are preferably provided adjacent to the tunnel barrier layer 122 located in the middle. In the manufacturing apparatus, these three layers are sequentially laminated without breaking the vacuum.
17 is an electrode layer of an eighth layer (Ta: tantalum), and 18 is a hard mask layer of a ninth layer (Ru: ruthenium). The ninth layer may be removed from the tunnel magnetoresistive element when used as a hard mask.

The crystalline ferromagnetic film 121 (CoFeB) as the fifth layer of the fixed magnetization layer, the sixth crystalline MgO layer as the tunnel barrier layer 122, and the seventh crystalline ferromagnetic film as the magnetization free layer 123 (CoFeB) forms the TMR element portion 12.
The crystalline ferromagnetic film 121 (CoFeB) and the crystalline ferromagnetic film 123 may be the same as the columnar crystal structure 61 shown in FIG.

  In FIG. 1, the numerical value in parentheses of each layer indicates the thickness of each layer, and the unit is “nm (nanometer)”. The said thickness is an example and is not limited to this.

   Next, with reference to FIG. 2, an apparatus and a manufacturing method for manufacturing the magnetoresistive element 10 having the above laminated structure will be described. FIG. 2 is a schematic plan view of an apparatus for manufacturing the magnetoresistive element 10, which is an apparatus capable of producing a multilayer film including a plurality of magnetic layers and a nonmagnetic layer, and is a mass production type sputtering film formation. Device.

   The magnetic multilayer film manufacturing apparatus 200 shown in FIG. 2 is a cluster type manufacturing apparatus and includes three film forming chambers based on a sputtering method. In this apparatus 200, a transfer chamber 202 having a robot transfer apparatus (not shown) is installed at the center position. The transfer chamber 202 of the manufacturing apparatus 200 for manufacturing the magnetoresistive element is provided with two load lock / unload lock chambers 205 and 206, respectively, for loading and unloading the substrate (for example, using a silicon substrate) 11. Done. By alternately loading and unloading the substrate between these load lock / unload lock chambers 205 and 206, the tact time is shortened and a magnetoresistive element can be manufactured with high productivity.

   In a manufacturing apparatus 200 for manufacturing a magnetoresistive element, three film forming magnetron sputtering chambers 201A, 201B, and 201C and one etching chamber 203 are provided around a transfer chamber 202. In the etching chamber 203, a required surface of the TMR element 10 is etched. Between the chambers 201A, 201B, 201C, and 203 and the transfer chamber 202, a gate valve 204 that can be opened and closed is provided. Each chamber 201A, 201B, 201C, and 202 is provided with a vacuum exhaust mechanism, a gas introduction mechanism, a power supply mechanism, and the like (not shown).

   A manufacturing apparatus 200 for manufacturing a magnetoresistive element includes magnetron sputtering chambers 201A, 201B, and 201C for film formation. Each of these apparatuses 201A, 201B, and 201C uses the magnetron DC high frequency sputtering method or the magnetron high frequency sputtering method to form the above-described first to ninth layers on the substrate 11 without breaking the vacuum. Each film can be deposited sequentially.

Four or five cathodes (31, 32, 33, 34, and 35) and cathodes (31, 32, 33, 34, and 35) disposed on an appropriate circumference are respectively provided on the ceilings of the film forming magnetron sputtering chambers 201A, 201B, and 201C. 41, 42, 43, 44 and 45) and cathodes (51, 52, 53 and 54) are arranged. Further, the substrate 11 is disposed on a substrate holder located coaxially with the circumference. The targets mounted on the cathodes (31, 32, 33, 34 and 35), the cathodes (41, 42, 43, 44 and 45) and the cathodes (51, 52, 53 and 54) are rotated in the back. A magnetron sputtering apparatus in which a magnet or a swinging magnet is arranged is preferable.
Further, high-frequency power such as radio frequency (RF frequency) or DC (direct current) power is applied to the cathode from the power input means 207A, 207B and 207C.
The high frequency power is in the range of 1 MHz to 3 GHz, preferably in the range of 5 MHz to 2 GHz and in the range of 100 W (watts) to 3000 W (watts), preferably in the range of 200 W (watts) to 2000 W (watts). Can be used.

In the present invention, when forming the ferromagnetic films 121 and 123 constituting the TMR element 12, a magnetron DC sputtering apparatus using the DC power source connected with the low-pass filter described above as the magnetron sputtering chambers 201A and 201C. Apply.
When forming the crystalline magnesium oxide layer 122 of the tunnel barrier layer, a magnetron high-frequency sputtering apparatus using a high-frequency power source connected with the above-described high-pass filter is applied as the magnetron sputtering chamber 201B.

   In the above, for example, a Ta (tantalum) target is attached to the cathode 31. A PtMn (platinum manganese alloy) target is attached to the cathode 32. A CoFeB (cobalt iron boron alloy) target is attached to the cathode 33. A CoFe (cobalt iron alloy) target is attached to the cathode 34. A Ru (ruthenium) target is attached to the cathode 35.

The cathode 41 is equipped with a MgO (magnesium oxide) target or a Mg (magnesium metal) target. When an Mg (magnesium metal) target is used, a reactive high-frequency sputtering chamber (not shown) for performing reactive sputtering can be connected to the transfer chamber 202 together with an oxidizing gas.
Further, after forming a crystalline magnesium layer by sputtering using a Mg (magnesium metal) target, in an oxidation chamber (not shown) using an oxidizing gas (for example, oxygen gas, ozone gas, water vapor, etc.) This crystalline magnesium alloy layer can be chemically changed to a crystalline magnesium oxide layer.

In another embodiment, an MgO (magnesium oxide) target can be attached to the cathode 41, and an Mg (magnesium metal) target can be attached to the cathode 42.
At this time, no target can be attached to the cathodes 43 to 45, and an MgO (magnesium oxide) target or an Mg (magnesium metal) target can also be attached to the cathodes 43 to 45.

A CoFeB (cobalt iron boron alloy) target is attached to the cathode 51. A Ta (tantalum) target is attached to the cathode 52. A Ru (ruthenium) target is attached to the cathode 53.
Further, the cathode 54 can be unmounted with a target. Alternatively, a CoFeB (cobalt iron boron alloy) target, a Ta (tantalum) target, or a Ru (ruthenium) target can be appropriately mounted for reservation.

Each in-plane direction of each target mounted on the cathode (31, 32, 33, 34 and 35), the cathode (41, 42, 43, 44 and 45), and the cathode (51, 52, 53 and 54) It is preferable that they be arranged non-parallel to the in-plane direction of the substrate. By using the non-parallel arrangement, a magnetic film and a nonmagnetic film having the same composition as the target composition can be deposited by sputtering while rotating a target having a smaller diameter than the substrate diameter.
In the non-parallel arrangement, for example, they can be arranged non-parallel so that the crossing angle between the target central axis and the substrate central axis is 45 ° or less, preferably 5 ° to 30 °.
Moreover, the rotation speed of 10 rpm-500 rpm, Preferably, the rotation speed of 50 rpm-200 rpm can be used for the board | substrate in this case.

  Deposition conditions of the TMR element portion 12 which is a main element portion of the present invention will be described. The ferromagnetic film 121 that is a magnetization fixed layer (the fifth CoFeB layer) uses a target having a CoFeB composition ratio (atomic: atomic ratio) of 60 / DC20 / 20, and an Ar (argon gas) pressure of 0.03 Pa. Film formation was performed at a sputtering rate of 0.64 nm / sec by magnetron DC sputtering (magnetron sputtering chamber 201A for film formation). The CoFeB layer (ferromagnetic film 121) at this time had an amorphous structure.

Subsequently, using a magnetron high-frequency RF sputtering apparatus (magnetron sputtering chamber 201B for film formation) using a low-pass filter shown in FIG. 7, sputtering is performed using a target having an MgO composition ratio (atomic: atomic ratio) of 50/50. Using Ar (argon gas) as the gas, the magnetron high frequency RF sputtering (13.56 MHz) is used for the sixth layer by using a pressure of 0.2 Pa in a pressure range of 0.01 to 0.4 Pa. A tunnel barrier layer 122 which is an MgO layer was formed. At this time, the MgO layer (tunnel barrier layer 122) had a crystal structure composed of an aggregate of columnar crystals.
At this time, the deposition rate of magnetron RF sputtering (13.56 MHz) was 0.14 nm / sec.

Subsequently, a ferromagnetic layer 123 as a magnetization free layer (seventh CoFeB layer) was formed using a magnetron DC sputtering apparatus (deposition magnetron sputtering chamber 201C).
At this time, it was confirmed that the CoFeB film (ferromagnetic film 123) of the seventh layer had an amorphous structure.
In this embodiment, the deposition rate of the MgO film was 0.14 nm / sec, but there is no problem even if the film is deposited in the range of 0.01 nm to 1.0 nm / sec.

The magnetoresistive element 10 on which the deposition was completed by performing the sputtering film formation in each of the magnetron sputtering chambers 201A, 201B, and 201C for film formation was subjected to an annealing process in a heat treatment furnace.
At this time, annealing was performed at an annealing temperature and time of about 300 ° C. for 4 hours in a magnetic field of 8 kOe.
As a result, it was confirmed that the CoFeB films of the fifth layer and the seventh layer having an amorphous structure had a crystal structure composed of the aggregate 61 of the columnar crystals 62 illustrated in FIG.
By this annealing process, the magnetic medium element 10 can act as a tunnel magnetoresistive element having a TMR effect.
Also, by this annealing step, predetermined magnetization was imparted to the antiferromagnetic material layer 14 which is the second PtMn layer.

FIG. 7 is a schematic view of the magnetron radio frequency sputtering apparatus of the present invention. In the figure, 701 is a sputtering chamber, 702 is a high-frequency power supply unit, 7021 is a blocking capacitor, 7022 is a well-known matching circuit, 7023 is a high-frequency power supply, 703 is a low-pass filter, 704 is a DC (direct current) power source for sputtering, and 705 is Magnet unit, 706 is a cathode electrode, 707 is a target (MgO target for forming a crystalline MgO layer), 708 is a known heating mechanism, 709 is a substrate holder (anode electrode), 710 is a substrate (wafer, glass substrate, etc.), 711 is a sputtering gas (inert gas such as Ar gas, He gas, Kr gas) supply system, 712 is a sputtering gas introduction system, 713 is an evacuation system (pump), and 714 is a plasma generation space.
FIG. 8 is a schematic view of the magnetron DC sputtering apparatus of the present invention. In the figure, 801 is a sputtering chamber, 802 is a DC (direct current) power supply unit, 8021 is a blocking capacitor, 8022 is a known matching circuit, 8023 is a DC power source, 803 is a high-pass filter, 804 is a DC (direct current) power source for sputtering, 805 is a magnet unit, 806 is a cathode electrode, 807 is a target (MgO target for forming a crystalline MgO layer), 808 is a known heating mechanism, 809 is a substrate holder (anode electrode), 810 is a substrate (wafer, glass substrate, etc.) 811 is a sputtering gas (inert gas such as Ar gas, He gas, Kr gas) supply system, 812 is a sputtering gas introduction system, 813 is an evacuation system (pump), and 814 is a plasma generation space.
In the present invention, a high-pass filter (not shown) can also be used for the DC power source 804 that supplies DC power to the substrate holder 809. At this time, the high pass filter is connected in series between the substrate holder 809 and the DC power source 804.
The direct current power from the DC power supply 8023 used in the present invention may be a long period pulse waveform. Specifically, the frequency can be set to 1000 Hz or less, preferably 10 Hz to 500 Hz.

  FIG. 3 is a block diagram of the apparatus of the present invention. In the figure, 301 is a transfer chamber corresponding to the transfer chamber 202 in FIG. 2, 302 is a film forming chamber corresponding to the film forming magnetron sputtering chamber 201A, 303 is a film forming chamber corresponding to the film forming magnetron sputtering chamber 201B, Denoted at 304 is a deposition chamber corresponding to the magnetron sputtering chamber 201C for deposition, 305 is a load lock / unload lock chamber corresponding to the load lock / unload lock chambers 205 and 206, and 306 is a central processing unit incorporating a storage medium 312. (CPU). Reference numerals 309 to 311 denote bus lines connecting the CPU 306 and the processing chambers 301 to 305, and control signals for controlling the operations of the processing chambers 301 to 305 are transmitted from the CPU 306 to the processing chambers 301 to 305.

  In one embodiment of the present invention, a substrate (not shown) in the load lock / unload lock chamber 305 is unloaded into the transfer chamber 301. This substrate unloading step is calculated based on a control program stored in the storage medium 312 by the CPU 306, and a control signal based on the calculation result is transmitted through the bus lines 307 and 311 to the load lock / unload lock chamber 305 and the transfer chamber. This is implemented by controlling the execution of various devices (for example, a gate valve, a robot mechanism, a transport mechanism, a drive system, etc., not shown) mounted on 301.

The substrate transferred to the transfer chamber 301 is transferred to the film formation chamber 302. Here, the first layer 13, the second layer 14, the third layer 15, the fourth layer 16, and the fifth layer 121 of FIG. 1 are sequentially stacked on the substrate carried into the deposition chamber 302. The CoFeB film of the fifth layer 121 at this stage preferably has an amorphous structure. In another embodiment, the CoFeB film of the fifth layer 121 at this stage may have a polycrystalline structure.
In the stacking process from the first layer to the fifth layer, the control signal calculated based on the control program stored in the storage medium 312 in the CPU 306 passes through the bus lines 307 and 308 and the transfer chamber 301 and the film formation. Controls the execution of various devices mounted on the chamber 302 (for example, an unillustrated cathode power supply mechanism, substrate rotation mechanism, gas introduction mechanism, exhaust mechanism, gate valve, robot mechanism, transport mechanism, drive system, etc.) Is implemented.

The substrate having the laminated film up to the fifth layer is once returned to the transfer chamber 301 and then transferred into the film formation chamber 303.
In the film formation chamber 303, a crystalline magnesium oxide film is formed as the sixth layer 122 on the amorphous CoFeB layer of the fifth layer 121.
In the film formation of the sixth layer 122, the control signal calculated based on the control program stored in the storage medium 312 in the CPU 306 is mounted on the transfer chamber 301 and the film formation chamber 303 through the bus lines 307 and 309. Implemented by controlling the execution of various devices (for example, a power input mechanism to a cathode (not shown), a substrate rotation mechanism, a gas introduction mechanism, an exhaust mechanism, a gate valve, a robot mechanism, a transport mechanism, a drive system, etc.) .

The substrate having the laminated film up to the sixth layer 122 is once again returned to the transfer chamber 301 and then transferred into the film formation chamber 304.
In the deposition chamber 304, the seventh layer 123, the eighth layer 17, and the ninth layer 18 are sequentially stacked on the crystalline magnesium oxide layer of the sixth layer 122. The CoFeB film of the seventh layer 123 at this stage preferably has an amorphous structure.

  In the laminated film forming process up to the ninth layer 18, the control signal calculated based on the control program stored in the storage medium 312 in the CPU 306 passes through the bus lines 307 and 310 and the transfer chamber 301 and the film forming chamber 304. By controlling the execution of various devices (for example, a power supply mechanism to a cathode (not shown), a substrate rotation mechanism, a gas introduction mechanism, an exhaust mechanism, a gate valve, a robot mechanism, a transport mechanism, a drive system, etc.) To be implemented.

  Examples of the storage medium 312 used in the present invention include hard disk media, magneto-optical disk media, flexible disk media, and non-volatile memories such as flash memory and MRAM, and include media that can store programs.

Further, the present invention provides the first layer to the second layer 121 in order to promote crystallization by annealing the amorphous CoFeB layers of the fifth layer 121 and the seventh layer 123 and to promote the magnetic application of the PtMn layer of the second layer 14. A laminated film composed of nine layers can be carried into an annealing furnace (not shown).
The storage medium 312 stores a control program for carrying out the process in the annealing furnace, and various apparatuses (not shown) in the annealing furnace are controlled by a control signal obtained by calculation of the CPU 306 based on the control program. For example, an annealing process can be performed by controlling a heater mechanism, an exhaust mechanism, a transport mechanism, and the like.

As a comparative example of the present invention, except that the use of the high-pass filter 803 illustrated in FIG. 8 is omitted, a 100-sample TMR element is manufactured by the same method as the above-described embodiment, and an MR ratio distribution (average Value, maximum value and minimum value).
As a result of the measurement, the average MR ratio was about 125%, the maximum MR ratio was 160%, and the minimum MR ratio was 98%. The number of samples within ± 5% of the average MR ratio was 32 samples.
The MR ratio is a phenomenon in which the electric resistance of the film changes as the magnetization direction of the magnetic film or magnetic multilayer film changes in response to an external magnetic field (Magneto-Resistive effect: MR effect). The change rate of the electrical resistance is the magnetoresistance change rate (MR ratio).

  On the other hand, in the present invention, as a result of measurement, the average MR ratio was 125%, which was almost the same as that of the comparative experiment, the maximum MR ratio was 132%, and the minimum MR ratio was 118%. The number of samples within ± 5% of the average MR ratio was 91 samples.

   In the present invention, the fifth layer 121 and the seventh layer 123 are replaced with the CoFeB alloy layer described above, a CoFeTaZr (cobalt iron tantalum zirconium) alloy layer, a CoTaZr (cobal tantalum zirconium) alloy layer, a CoFeNbZr (cobalt iron). A crystalline ferromagnetic layer such as a niobium zirconium) alloy layer, a CoFeZr (cobalt iron zirconium) alloy layer, a FeTaC (iron tantalum carbon) alloy layer, a FeTaN (iron tantalum nitrogen) alloy layer, or a FeC (iron carbon) alloy layer is used. be able to.

In the present invention, an Rh (rhodium) layer or an Ir (iridium) layer can be used instead of the Ru (ruthenium) layer of the fourth layer 16.
In the present invention, instead of the PtMn (platinum manganese alloy) layer of the second layer 14, an IrMn (iridium manganese alloy) layer, an IrMnCr (iridium manganese chromium alloy) layer, a NiMn (nickel manganese alloy) layer, a PdPtMn ( A lead platinum manganese alloy) layer, a RuRhMn (ruthenium rhodium manganese alloy) layer, OsMn (osnium manganese) or the like is also preferably used. The film thickness is preferably 10 to 30 nm.

In another embodiment of the present invention, the polycrystalline CoFeB alloy layer of the fifth layer 121 can be a two-layer film of a crystalline CoFeB alloy layer and a crystalline CoFe alloy layer (located on the substrate side).
The crystalline CoFe alloy layer located on the substrate side can be formed in a crystalline state on the fourth PtMn alloy layer by sputtering.
The present inventors have confirmed that the CoFeB layer following the formation of the crystalline CoFe alloy layer has an amorphous structure immediately after the sputtering film formation (before the annealing step).
The present invention can further change the phase to an epitaxial polycrystalline structure by annealing the CoFeB layer having the amorphous structure.

FIG. 4 shows an MRAM (Magnetoresistive) using the magnetoresistive element of the present invention as a memory element.
1 is a schematic diagram of a (Rndom Access Memory: ferroelectric memory) 401. FIG. In the MRAM 401, 402 is a memory element of the present invention, 403 is a word line, and 404 is a bit line. Each of the large number of memory elements 402 is arranged at each intersection position of a plurality of word lines 403 and a plurality of bit lines 404, and is arranged in a lattice-like positional relationship. Each of the large number of memory elements 402 can store 1-bit information.

   FIG. 5 is an equivalent circuit diagram including the TMR element 10 that stores 1-bit information and the transistor 501 having a switch function at the intersection of the word line 403 and the bit line 404 of the MRAM 401.

   The present invention is used as a memory element of an MRAM that can be mass-produced, has high practicality, and can be highly integrated.

10 Magnetic medium 11 Substrate 12 TMR element portion 121 Ferromagnetic film (fifth layer)
122 Tunnel barrier layer (6th layer)
123 Ferromagnetic film (seventh layer; magnetization free layer)
13 Lower electrode layer (first layer; underlayer)
14 Antiferromagnetic film (second layer)
15 Ferromagnetic film (third layer)
16 Nonmagnetic film for exchange coupling (fourth layer)
17 Upper electrode layer (8th layer)
18 Hard mask layer (9th layer)
19 Magnetization fixed layer 200 Magnetoresistive element creation apparatus 201A film formation chamber 201B film formation chamber 201C film formation chamber 202 transfer chamber 203 etching chamber 204 gate valve 205 load lock / unload lock chamber 206 load lock / unload lock chambers 31-35 Cathode 41-45 Cathode 51-54 Cathode 207A Power input unit 207B Power input unit 207C Power input unit 301 Transfer chamber 302 303 304 Film formation chamber 305 Load lock / unload lock chamber 306 Central processing unit (CPU)
307 to 311 Bus line 312 Storage medium 401 MRAM
402 Memory element 403 Word line 404 Bit line 501 Transistor 61 Column-shaped crystal group assembly 62 Column-shaped crystal 701 Sputtering chamber 702 High-frequency power supply unit 7021 Blocking capacitor 7022 High-frequency power supply 703 Low-pass filter 704 Sputtering DC (DC) ) Power supply 705 Magnet unit 706 Cathode electrode 707 Target 708 Heating mechanism 709 Substrate holder (anode electrode)
710 substrate (wafer, glass substrate, etc.)
711 Sputtering gas supply system 712 Sputtering gas introduction system 713 Vacuum exhaust system 714 Plasma generation space 801 Sputtering chamber 802 DC power supply unit 8021 Blocking capacitor 8022 Matching circuit 8023 DC power supply 803 High pass filter 804 Sputtering DC (direct current) power supply 805 Magnet unit 806 Cathode electrode 807 Target 808 Heating mechanism 809 Substrate holder (anode electrode)
810 substrate (wafer, glass substrate, etc.)
811 Sputtering gas supply system 812 Sputtering gas introduction system 813 Vacuum exhaust system 814 Plasma generation space

Claims (9)

A ferromagnetic thin film amorphous film is formed by direct current magnetron sputtering of a target having a ferromagnetic material under application of direct current power with a high frequency component cut by a high frequency component cut filter, and the target having magnesium oxide is applied with high frequency power. The manufacturing method of the magnetic medium characterized by having the process of forming the thin film crystal | crystallization of magnesium oxide by carrying out high frequency magnetron sputtering. The method of manufacturing a magnetic medium according to claim 1, wherein the DC power is set to a pulse waveform power. The method of manufacturing a magnetic medium according to claim 1, wherein the high-frequency component cut filter is set to cut a frequency component in a range of radio frequency to 3 GHz. A first step of forming a first ferromagnetic film in an amorphous state by DC magnetron sputtering of a target having a first ferromagnetic material under application of direct current power with a high frequency component cut by a high frequency component cut filter; A second step of forming a crystalline magnesium oxide film by performing magnetron sputtering of a target having magnesium oxide under application of high-frequency power with a low-frequency component cut by a low-frequency component cut filter after one step; After two steps, an amorphous second ferromagnetic film is formed by DC magnetron sputtering on a target having a second ferromagnetic material under application of direct current power with high frequency components cut by a high frequency component cut filter. Third step, and after the third step, the magnesium oxide A fourth step of annealing the amorphous film, the amorphous first ferromagnetic film, and the amorphous second ferromagnetic film, thereby causing a phase change from the amorphous state to the crystalline state. And forming a tunnel magnetoresistive effect element. The method of manufacturing a magnetic medium according to claim 4, wherein the frequency of the low frequency component is set in a range of 5000 KHz or less. The method of manufacturing a magnetic medium according to claim 4, wherein the frequency of the low frequency component is set in a range of 10 KHz to 3000 KHz. The magnetic medium manufacturing method according to claim 4, wherein the high-frequency component cut filter is set so as to cut a high-frequency component in a range of a radio frequency to 3 GHz. When the operation is performed, a ferromagnetic thin film amorphous is formed by DC magnetron sputtering of a target having a ferromagnetic material under application of DC power from which a high frequency component has been cut by a high frequency component cut filter, and a target having magnesium oxide. A sputtering apparatus comprising a storage medium storing a control program for executing a step of forming a magnesium oxide thin film crystal by performing high-frequency magnetron sputtering under application of high-frequency power. When the operation is executed, a first ferromagnetic film is formed in an amorphous state by DC magnetron sputtering on a target having a first ferromagnetic material under application of DC power from which a high frequency component is cut by a high frequency component cut filter. After the first step, a crystalline magnesium oxide film is formed by magnetron sputtering a target having magnesium oxide under application of high frequency power with low frequency components cut by a low frequency component cut filter. Step, after the second step, a second ferromagnetic film in an amorphous state by DC magnetron sputtering of a target having a second ferromagnetic material under application of direct current power with high frequency components cut by a high frequency component cut filter A third step of forming a film, and after the third step, the acid Performing a fourth step of annealing the magnesium phosphide film, the amorphous first ferromagnetic film, and the amorphous second ferromagnetic film, thereby causing a phase change from the amorphous state to the crystalline state. A sputtering apparatus comprising a storage medium storing a control program for executing a step of forming a tunnel magnetoresistive effect element by using.