JP2009055049A - Multi chamber film-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-chamber film-forming apparatus capable of manufacturing spin-valve giant magnetoresistive films satisfying both high magnetoresistive change ratio (MR ratio) and low interlayer coupling magnetic field (Hin). <P>SOLUTION: The multi-chamber film-forming apparatus is equipped with a substrate transferring robot for transferring a substrate in the order of a first film-forming chamber 13A to film-form an anti-ferromagnetic layer, a plasma treating chamber 14 for plasma treatment, a first film-forming chamber 13A to film-form a magnetization fixing layer, a plasma treating chamber 14 for plasma treatment, and a second film-forming chamber 13B to film-form a nonmagnetic conduction layer or oxide layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method of manufacturing a spin valve type giant magnetoresistive thin film, and more particularly to a multi-chamber film forming apparatus used for manufacturing a high performance spin valve type giant magnetoresistive thin film suitable for a magnetic reproducing head of a magnetic disk drive.

  A spin-valve giant magnetoresistive thin film used in a magnetic read head of a magnetic disk drive is a multilayer film composed of a plurality of layers (thin films) of an antiferromagnetic layer, a magnetization fixed layer, a nonmagnetic conductive layer, and a magnetization free layer. It has a structure. In the multilayer structure of the spin valve type giant magnetoresistive thin film, a nonmagnetic conductive layer is provided between the magnetization fixed layer and the magnetization free layer, and is separated by the nonmagnetic conductive layer. In addition, since the antiferromagnetic layer is adjacent to the magnetization fixed layer, the magnetic moment of the magnetization fixed layer is fixed in one direction by exchange coupling with the antiferromagnetic layer. On the other hand, the magnetic moment of the magnetization free layer is freely rotated according to the external magnetic field.

  In the spin valve type giant magnetoresistive thin film, a so-called giant magnetoresistive effect is obtained in which the electrical resistance changes depending on the relative angle formed by the magnetic moment of the magnetization fixed layer and the magnetic moment of the magnetization free layer. The rate of change in electrical resistance due to the giant magnetoresistance effect is called magnetoresistance change rate (MR ratio), and the MR ratio of the spin valve type giant magnetoresistive thin film is much higher than that of the conventional anisotropic magnetoresistive thin film. It has the characteristic.

  There are three types of spin valve type giant magnetoresistive thin films. In the first type, as shown in FIG. 17, the buffer layer 112, the antiferromagnetic layer 113, the magnetization fixed layer 114, the nonmagnetic conductive layer 115, the magnetization free layer 116, and the protective layer 117 are sequentially arranged from the substrate 111 side. It is a so-called bottom type that is laminated. In the second type, as shown in FIG. 18, the buffer layer 112, the magnetization free layer 116, the nonmagnetic conductive layer 115, the magnetization fixed layer 114, the antiferromagnetic layer 113, and the protective layer 117 are sequentially arranged from the substrate 111 side. It is a so-called top type that is laminated. As shown in FIG. 19, the third type includes a buffer layer 112, a first antiferromagnetic layer 113A, a first magnetization fixed layer 114A, a first nonmagnetic conductive layer 115A, a magnetization free layer 116, a first layer from the substrate 111 side. 2 is a so-called dual type in which a nonmagnetic conductive layer 115B, a second magnetization fixed layer 114B, a second antiferromagnetic layer 113B, and a protective layer 117 are successively stacked.

  In the above-described three types of spin-valve giant magnetoresistive thin films, the magnetic pinned layers 114, 114A, 114B, which have conventionally been a single layer, are further laminated to a laminated ferrimagnetic layer element including a magnetic pinned layer element, a nonmagnetic layer, and a magnetic pinned layer element. A thin film replaced with a structure has also been proposed (US Pat. No. 5,465,185). Further, the magnetization free layer 116 may be a single layer structure or a multilayer structure. In the multilayer structure of the magnetization free layer and the magnetization fixed layer, all are magnetic films, but different magnetic films may be laminated or a sandwich structure with a nonmagnetic film sandwiched therebetween may be formed.

  The giant magnetoresistive effect of the spin valve giant magnetoresistive thin film is caused by spin-dependent scattering at the laminated interface of the laminated film. Therefore, in order to obtain a high MR ratio, the cleanliness and flatness of the interface are important in the manufacturing process of the spin valve film. Therefore, in the spin valve type giant magnetoresistive thin film, in order to achieve cleanliness and flatness of the interface, the same vacuum chamber is used so that the deposition interval between layers is as short as possible continuously in a high vacuum. Often formed into a film.

  Examples of film forming techniques in vacuum include magnetron sputtering, ion beam sputtering, ECR sputtering, counter target sputtering, high frequency sputtering, electron beam evaporation, resistance heating evaporation, and MBE (Molecular Beam Epitaxy).

  In order to obtain a high MR ratio, the nonmagnetic conductive layer 115 should be thin in order to suppress the flow of conduction electrons (shunt effect) that does not contribute to the giant magnetoresistance effect. However, if the film thickness of the nonmagnetic conductive layer 115 is reduced, the magnetization fixed layer 114 and the magnetization free layer 116 are ferromagnetically coupled via the nonmagnetic conductive layer 115. The interlayer coupling magnetic field (Hin) between the magnetization fixed layer and the magnetization free layer is preferably small in practical use of the magnetic reproducing head of the magnetic disk drive device, and the magnetic field having a value included in the range of −10 to +10 Oe. desirable. Conventionally, in order to reduce the interlayer coupling magnetic field, the film thickness of the nonmagnetic conductive layer 115 has been set to 2.5 to 3.5 nm.

  Further, in the conventional technique, in a bottom type spin valve film, a ferromagnetic oxide generated between a magnetization fixed layer and a magnetization free layer by inserting a very thin oxide layer (NOL: Nano oxide layer) of 1 nm or less into the magnetization fixed layer. A technique for reducing binding has also been proposed (Y. Kamiguchi et al .: Digests of INTERMAG '99, DB-01). As a result, a relatively small interlayer coupling magnetic field is obtained even when the nonmagnetic conductive layer is thin (2 to 2.5 nm), and a high MR ratio is obtained.

  In the conventional spin-valve type giant magnetoresistive thin film, the thickness of the nonmagnetic conductive layer is set to be thick (2.5 to 3.5 nm) in order to reduce the interlayer coupling magnetic field, but this does not contribute to the giant magnetoresistive effect. There is a problem that a flow of conduction electrons (shunt effect) occurs and the MR ratio is lowered. Furthermore, in the manufacturing process of the above-mentioned extremely thin oxide layer, an oxidation process is required during the formation of the magnetization fixed layer. The oxidation process is complicated and reproducibility is difficult to obtain.

An object of the present invention is to solve the above-described problem. Even when the nonmagnetic conductive layer is thin, a high MR ratio can be obtained by keeping the interlayer coupling magnetic field low without using an oxidation process. An object of the present invention is to provide a multi-chamber film forming apparatus capable of manufacturing a spin valve type giant magnetoresistive thin film.

The multi-chamber film forming apparatus according to the present invention is configured as follows to achieve the above object.

The first multi-chamber apparatus, a vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited antiferromagnetic layer and the magnetization fixed layer, and, coupled arranged in the vacuum transfer chamber, having a pulp plasma processing chamber to generate a plasma of inert gas, the substrate transfer robot, the substrate was carried into the first film forming chamber, said first after completion of film formation of the antiferromagnetic layer in one deposition chamber, and unloaded from the first film forming chamber is carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, from the plasma processing chamber out and then carried into the first film forming chamber, characterized in that the post-deposition termination of the first magnetization pinned layer in the film forming chamber is for unloading from the first deposition chamber.

The second multi-chamber apparatus, a vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in the vacuum transfer chamber, the first film forming chamber deposited antiferromagnetic layer and the magnetization fixed layer, coupled arranged in the vacuum transfer chamber, a second film forming chamber for forming the non-magnetic conductive layer or an oxide layer as well as the coupled arranged in the vacuum transfer chamber, Help plasma processing to generate plasma of the inert gas has a chamber, the substrate transfer robot, the substrate was carried into the first film forming chamber, after completion of film formation of the antiferromagnetic layer in the first film forming chamber, from the first film forming chamber out and then carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the first film forming chamber, the magnetization fixed in the first film forming chamber after completion deposition layer, to the plasma processing chamber and unloaded from the first film forming chamber Type, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the second film forming chamber, formed of non-magnetic conductive layer or an oxide layer in the second film forming chamber after film ends, characterized in that for unloading from the second film formation chamber.

The third multi-chamber apparatus, a vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited buffer layer and the antiferromagnetic layer, and coupled arranged in the vacuum transfer chamber, having a pulp plasma processing chamber to generate a plasma of inert gas, the substrate transfer robot, the substrate was carried into the first film forming chamber, said first after completion formation of the buffer layer in the film forming chamber, and unloaded from the first film forming chamber is carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber carried into the first film forming chamber, characterized in that the post-deposition termination of the antiferromagnetic layer in the first film forming chamber, in which is unloaded from the first film forming chamber.

The fourth multi-chamber apparatus, a vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited the magnetization free layer, said vacuum transfer chamber coupled arrangement, the buffer layer and the second film forming chamber you deposited nonmagnetic conductive layer or an oxide layer, and, coupled arranged in the vacuum transfer chamber, Help plasma to generate a plasma of inert gas It includes a processing chamber, the substrate transfer robot unloading, the substrate was carried into the second film forming chamber, after completion of film formation of the buffer layer in the second film formation chamber, from the second film formation chamber and then carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the first film forming chamber, the magnetization free layer in the first film forming chamber after completion of the deposition, carried into the plasma processing chamber and unloaded from the first film forming chamber , After the plasma treatment completion in the plasma processing chamber, said plasma processing chamber and unloaded from and carried into the second film forming chamber, the completion of film formation of the non-magnetic conductive layer or an oxide layer at a second deposition chamber after, characterized in that it is intended to be transferred out from the second film formation chamber.

According to the present invention, since the film formation is temporarily interrupted during the film formation of the spin valve type giant magnetoresistive thin film and the predetermined interface is subjected to the plasma treatment or the like, the magnetization fixed layer formed by sandwiching the nonmagnetic conductive layer And the magnetic coupling between the magnetization fixed layer and the magnetization free layer can be reduced to −10 to −10 even when the nonmagnetic conductive layer is thin. A high MR ratio can be obtained by maintaining the magnetic field within the range of +10 Oe. Further, according to the present invention, since no process using oxygen or oxidation process is used, a high MR ratio can be obtained stably with good reproducibility.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 shows a block diagram of a multi-chamber deposition apparatus according to the present invention used in carrying out the manufacturing method of the scan pin valve type giant magnetoresistive film. The film forming apparatus 10 is a multi-chamber type film forming apparatus. The film forming apparatus 10 includes a vacuum transfer chamber 12 in which a substrate transfer robot 11 is provided, a film forming chamber 13A, a film forming chamber 13B, a plasma processing chamber 14 and a load lock chamber 15 coupled to the vacuum transfer chamber 12. Consists of The film forming chambers 13A and 13B are sputtering film forming chambers each provided with various types of cathodes. The movement of the substrate among the film forming chamber 13A, the film forming chamber 13B, the plasma processing chamber 14, and the load lock chamber 15 is performed by the substrate transfer robot 11 provided in the vacuum transfer chamber 12. Gate valves 16 are provided between the film forming chamber 13A, the film forming chamber 13B, the plasma processing chamber 14, and the load lock chamber 15, respectively.

  The internal structure of the plasma processing chamber 14 is shown in FIG. The plasma processing chamber 14 is formed of a vacuum chamber 21, and an upper electrode 22 and a lower electrode 23 are provided in the vacuum chamber 21. The upper electrode 22 is grounded, and the lower electrode 23 is connected to an RF power source (high frequency power source) 25 via a matching box 24. A substrate 25 is mounted on the lower electrode 23. Plasma 26 is generated between the upper electrode 22 and the lower electrode 23 in a state where the plasma generation condition is satisfied.

As a typical example of the processing operation of the plasma processing chamber 14, 0.075 Pa Ar gas is introduced into the vacuum chamber 21, and RF of 15 W (0.029 W / cm ² per unit area) is applied to the lower electrode 23. The plasma 26 is generated by applying power, and the plasma treatment is performed under the condition that the substrate bias voltage (Vdc) is smaller than 0V and is in the range of −300V or higher. The upper limit value of the substrate bias voltage is preferably −2 to −3 V, and the most preferable voltage is a voltage included in a range from −15 V to the upper limit value of the substrate bias voltage. This voltage is a voltage capable of generating plasma. As a process gas introduced into the vacuum chamber 21, an inert gas such as Kr, Xe, Ne or the like or a gas similar thereto can be used instead of Ar. The pressure of the process gas in the plasma processing chamber 14 is set to a low pressure in the range of 0.01 to 100 Pa.

  Four types of targets 31 are installed in the film forming chamber 13A, and the materials thereof are PtMn, CoFe, and NiFe. Also, four types of targets 32 are installed in the film forming chamber 13B, and the materials thereof are Cu, Ta, and Ru. The substrate 25 is moved between the film forming chambers 13A and 13B and the plasma processing chamber 14 by the substrate transfer robot 11, and a multilayer film having a desired laminated structure is formed.

  As an example, FIG. 3 shows a laminated structure of a bottom type spin valve type giant magnetoresistive thin film. According to this laminated structure, Ta (3 nm) / NiFe (2 nm) / PtMn (12 nm) / CoFe (1.8 nm) / Ru (0.8 nm) / CoFe (2.8 nm) / Cu (2.2 nm) / The layers are successively laminated in the order of CoFe (1.5 nm) / NiFe (2.5 nm) / Cu (1 nm) / Ta (3 nm). The numerical value described in parentheses in each layer is the thickness of the layer, and the unit is “nm (nanometer)”. In the above laminated structure, Ta (3 nm) and NiFe (2 nm) are buffer layers 41, PtMn (12nm) is an antiferromagnetic layer 42, CoFe (1.8nm), Ru (0.8nm), and CoFe (2.8nm) are fixed magnetization. Layer (laminated ferrimagnetic layer) 43, Cu (2.2 nm) is a nonmagnetic conductive layer 44, CoFe (1.5 nm) and NiFe (2.5 nm) are magnetization free layers 45, Cu (1 nm) is a spin filter 46, Ta (3 nm) is This is a protective layer 47. In order to form a bottom type spin valve film as described above, first, Ta (3 nm) is formed in the film forming chamber 13B, and then NiFe (2 nm) / PtMn (12 nm) / CoFe is formed in the film forming chamber 13A. (1.8 nm) is deposited, then Ru (0.8 nm) is deposited in the deposition chamber 13B, then CoFe (2.8 nm) is deposited in the deposition chamber 13A, and then in the deposition chamber 13B. Cu (2.2 nm) is deposited, then CoFe (1.5 nm) / NiFe (2.5 nm) is deposited in the deposition chamber 13A, and finally Cu (1 nm) / Ta (3 nm) is deposited in the deposition chamber 13B. Form a film.

  Plasma treatment is appropriately performed in the film formation process of the bottom type spin valve type giant magnetoresistive thin film. When plasma processing is performed, film formation is temporarily interrupted at a desired interface, the substrate 25 is transferred to the plasma processing chamber 14, and plasma processing is executed.

  In the film forming process of the bottom type spin valve film, for example, when the Ru (0.8 nm) / CoFe (2.8 nm) interface is subjected to plasma treatment, it is as follows. First, Ta (3 nm) is deposited in the deposition chamber 13B, then NiFe (2 nm) / PtMn (12 nm) / CoFe (1.8 nm) is deposited in the deposition chamber 13A, and then in the deposition chamber 13B. After forming the Ru (0.8 nm) film, it is transferred to the plasma processing chamber 25 and subjected to the plasma processing based on the processing conditions described above, and then CoFe (2.8 nm) is formed in the film forming chamber 13A. Cu (2.2 nm) is deposited in the deposition chamber 13B, then CoFe (1.5 nm) / NiFe (2.5 nm) is deposited in the deposition chamber 13A, and finally Cu (1 nm) / is deposited in the deposition chamber 13B. Ta (3 nm) is deposited.

  In the description of the above embodiment, plasma processing is performed as an example of processing a predetermined interface. However, this plasma processing is a broad concept, and the interface is processed by ion bombardment with an inert gas, or neutral. Includes treatment with particles, radicals, atoms, and other particles. The same effect can be obtained by replacing with ion beam etching using an ion gun.

  Next, an embodiment of a method for manufacturing a spin valve type giant magnetoresistive thin film according to the present invention will be described in detail with reference to FIGS. In the description of this embodiment, the plasma treated interface is revealed.

  (Example 1): Example 1 relates to a method of manufacturing the bottom type spin valve type giant magnetoresistive thin film shown in FIG. That is, from the substrate 25 side, Ta (3 nm) / NiFe (2 nm) / PtMn (12 nm) / CoFe (1.8 nm) / Ru (0.8 nm) / CoFe (2.8 nm) / Cu (2.2 nm) / CoFe (1.5 nm) This is an example in which plasma processing is performed in the middle of film formation by a manufacturing method of a bottom type spin valve film having a laminated structure of / NiFe (2.5 nm) / Cu (1 nm) / Ta (3 nm). In FIG. 6, when the horizontal axis is “no plasma treatment”, plasma treatment is performed at each of “PtMn / CoFe interface”, “CoFe / Ru interface”, “Ru / CoFe interface”, and “CoFe / Cu interface”. In this case, the vertical axis represents MR ratio and Hin, and a characteristic diagram showing changes in MR ratio and Hin is shown. In this example, the plasma treatment time was unified to 15 seconds, and the plasma treatment interface was changed. As a result, the plasma treatment at the PtMn / CoFe interface, CoFe / Ru interface, Ru / CoFe interface, and CoFe / Cu interface reduced Hin. Was able to be realized. At the same time, the MR ratio was improved by plasma treatment at the Ru / CoFe interface and the CoFe / Cu interface. For this reason, in the film configuration of this example, it is preferable to plasma-treat the Ru / CoFe interface or the CoFe / Cu interface, and more preferably to plasma-treat both the Ru / CoFe interface and the CoFe / Cu interface.

  Ta (3nm) / NiFe (2nm) / PtMn (12nm) / CoFe (1.8nm) / Ru (0.8nm) / CoFe (2.8nm) / Cu (2.2nm) / CoFe (1.5nm) / NiFe (2.5nm) In the bottom type spin valve film having a stacked structure of / Cu (1 nm) / Ta (3 nm), the interface of NiFe (2 nm) / PtMn (12 nm), the interface of PtMn (12 nm) / CoFe (1.8 nm), CoFe (1.8 nm) nm) / Ru (0.8 nm) interface, Ru (0.8 nm) / CoFe (2.8 nm) interface, and CoFe (2.8 nm) / Cu (2.2 nm) interface to reduce the Hin. An improvement in MR ratio is expected. In FIG. 3, the interface pointed by a right-pointing arrow is an interface that is preferably subjected to plasma treatment.

  (Example 2): Example 2 relates to a method of manufacturing the top-type spin-valve giant magnetoresistive thin film shown in FIG. That is, from the substrate 25 side, Ta (3 nm) / NiFe (2.5 nm) / CoFe (1.5 nm) / Cu (2.2 nm) / CoFe (2.8 nm) / Ru (0.8 nm) / CoFe (1.8 nm) / PtMn (12 nm ) / Ta (3 nm) is an example in which plasma treatment is performed in the middle of film formation by a method for producing a top type spin valve film having a laminated structure. In this stacked structure, Ta (3 nm) is a buffer layer 41, NiFe (2.5 nm) / CoFe (1.5 nm) is a magnetization free layer 45, Cu (2.2 nm) is a nonmagnetic conductive layer 44, CoFe (2.8 nm) / Ru (0.8 nm) / CoFe (1.8 nm) is a magnetization fixed layer (laminated ferrimagnetic layer) 43, PtMn (12 nm) is an antiferromagnetic layer 42, and Ta (3 nm) is a protective layer 47. In FIG. 7, when the horizontal axis is “no plasma treatment”, plasma treatment is performed at each of “Ta / NiFe interface”, “CoFe / Ru interface”, “Cu / CoFe interface”, and “Ru / CoFe interface”. In this case, the vertical axis represents MR ratio and Hin, and a characteristic diagram showing changes in MR ratio and Hin is shown. In this embodiment, the plasma treatment time is unified to 15 seconds and the plasma treatment interface is changed. As shown in FIG. 7, the reduction of Hin can be realized by the plasma treatment of the Ta / NiFe interface and the CoFe / Cu interface. It was. The MR ratio was improved in the plasma treatment of Ru / CoFe interface. Therefore, in the film configuration of this example, it is preferable to perform plasma treatment on at least one of the Ta / NiFe interface, the CoFe / Cu interface, and the Ru / CoFe interface, and plasma treatment is performed on both the CoFe / Cu interface and the Ru / CoFe interface. More preferably. The same effect can be expected even if the CoFe / Ru interface is plasma treated. In FIG. 4, the interface pointed by a right-pointing arrow is an interface that is preferably subjected to plasma treatment.

  Example 3 In Example 3, an example in which the plasma processing time in the method for manufacturing the bottom type spin valve giant magnetoresistive thin film shown in FIG. 3 is changed will be described. FIG. 8 is a characteristic diagram showing changes in MR ratio and Hin when the horizontal axis is the plasma processing time (seconds; sec) and the vertical axis is the MR ratio and Hin. According to FIG. 8, in the bottom type spin valve film, when the processing time of the Ru / CoFe interface is changed, the plasma processing time of the Ru / CoFe interface is in the range of 10 to 30 seconds at which the highest MR ratio can be obtained. It can be seen that the time contained in is preferred.

  Example 4 Example 4 relates to a method of manufacturing the dual type spin valve giant magnetoresistive thin film shown in FIG. That is, from the substrate 25 side, Ta (3 nm) / NiFe (2 nm) / PtMn (12 nm) / CoFe (1.8 nm) / Ru (0.8 nm) / CoFe (2.8 nm) / Cu (2.2 nm) / CoFe (0.5 nm) /NiFe(3nm)/CoFe(0.5nm)/Cu(2.2nm)/CoFe(2.8nm)/Ru(0.8nm)/CoFe(1.8nm)/PtMn(12nm)/Ta(3nm) This is an example in which plasma processing is performed in the middle of film formation by a manufacturing method of a dual type spin valve film. In this laminated structure, Ta (3 nm) / NiFe (2 nm) is the buffer layer 41, PtMn (12 nm) is the first antiferromagnetic layer 42A, CoFe (1.8 nm) / Ru (0.8 nm) / CoFe (2.8 nm) is The first magnetization fixed layer (first laminated ferri) 43A, Cu (2.2 nm) is the first nonmagnetic conductive layer 44A, CoFe (0.5 nm) / NiFe (3 nm) / CoFe (0.5 nm) is the magnetization free layer 45, Cu (2.2 nm) is the second nonmagnetic conductive layer 44B, CoFe (2.8 nm) / Ru (0.8 nm) / CoFe (1.8 nm) is the second magnetization fixed layer (second laminated ferri) 43B, and PtMn (12 nm) is the first 2 The antiferromagnetic layer 42B, Ta (3 nm) is the protective layer 47. In FIG. 9, the horizontal axis is “Ru / CoFe interface”, “Ru / CoFe interface and Cu / CoFe interface”, and “Ru / CoFe interface and Cu / CoFe interface and Ru / CoFe interface”. In this case, the vertical axis represents MR ratio and Hin, and a characteristic diagram showing changes in MR ratio and Hin is shown. In this example, the plasma treatment time was unified to 15 seconds and the plasma treatment interface was changed. When the plasma treatment was performed on the three interfaces of the Ru / CoFe interface, the Cu / CoFe interface, and the Ru / CoFe interface, the reduction of Hin was achieved. And improved MR ratio. Therefore, in the film configuration of this example, it is preferable to perform plasma treatment on any of the three interfaces of the Ru / CoFe interface, the Cu / CoFe interface, and the Ru / CoFe interface. However, in order to further reduce the Hin and improve the MR ratio. It is preferable to plasma-treat all three interfaces of the Ru / CoFe interface, the CoFe / Cu interface, and the Ru / CoFe interface. In FIG. 5, the interface pointed by a right-pointing arrow is an interface on which plasma treatment is desirable.

  Example 5 In Example 5, an example in which the plasma processing time in the method for manufacturing the bottom type spin valve giant magnetoresistive thin film shown in FIG. 3 is changed will be described. FIG. 10 is a characteristic diagram showing changes in MR ratio and Hin when the horizontal axis is the plasma processing time (second; sec) and the vertical axis is the MR ratio and Hin. FIG. 10 shows an example in which the plasma processing time at the Ru / CoFe interface is unified to 15 seconds and the plasma processing time at the CoFe / Cu interface is changed in the bottom type spin valve film. According to this example, it can be seen that the plasma treatment time at the CoFe / Cu interface is preferably 30 seconds at which the lowest Hin is obtained.

  (Example 6): In Example 6, in the production of the laminated structure of the above-mentioned bottom type spin valve type giant magnetoresistive thin film shown in FIG. 3, no plasma treatment was performed, and Ru (0.8 nm) and CoFe (2.8 nm) of CoFe oxide layer (NOL) with a thickness of 1 nm or less, and Ru (0.8 nm) / CoFe (2.8 nm) interface for 15 seconds plasma treatment A comparison of MR curves is shown. In FIG. 11, the horizontal axis indicates the magnetic field strength, the vertical axis indicates the MR ratio, and the NOL is sandwiched between the MR curve 51 when no plasma treatment is performed and Ru (0.8 nm) and CoFe (2.8 nm). The MR curve 52 in this case and the MR curve 53 when the Ru (0.8 nm) / CoFe (2.8 nm) interface is plasma-treated for 15 seconds are shown. According to FIG. 11, the MR ratio was improved from 7.9% to 10.4% by inserting NOL in the same film structure, and 11.2% was obtained when the plasma treatment was further performed. The same effect can be obtained by forming a CoFe layer having a thickness of 1 to 4 nm after inserting the NOL and then performing plasma treatment. Further, the coercive force (Hc) of the magnetization free layer composed of CoFe (1.5 nm) / NiFe (2.5 nm) of the spin valve film without the plasma treatment was 0.6 Oe, whereas NOL was inserted. When the plasma treatment was performed, the value was 1.3 Oe. The smaller the Hc of the magnetization free layer composed of the soft magnetic material of CoFe and NiFe, the better. The secondary effect that the Hc is not deteriorated by the plasma treatment as in this example was also obtained.

  (Example 7): Example 7 is the same as in Example 6 described above, in the case of no plasma treatment in the bottom type spin valve film, in the case of inserting NOL, and in the case of plasma treatment of the Ru / CoFe interface. FIG. 9 shows the dependency of the MR ratio on the Cu layer thickness (FIG. 12) and the dependency of Hin on the Cu layer thickness (FIG. 13) when the Ru / CoFe interface and the CoFe / Cu interface are plasma treated. In FIG. 12, the horizontal axis represents the Cu layer thickness (nm), the vertical axis represents MR (%), the horizontal axis in FIG. 13 represents the Cu layer thickness (nm), and the vertical axis represents Hin (Oe). As shown in FIG. 12 and FIG. 13, in the case of no plasma treatment, Hin increases as the Cu layer thickness decreases, and when the Cu layer thickness decreases to 2.1 nm or less, the MR ratio decreases, but Ru / CoFe When only the interface is plasma-treated, and when the Ru / CoFe interface and the CoFe / Cu interface are plasma-treated, Hin vibrates with respect to the Cu layer thickness, and a high MR ratio is obtained even when the Cu layer thickness is reduced to 2 nm or less. maintain.

  (Example 8): Example 8 is an MR curve measure in the case where the Ru / CoFe interface in the bottom type spin valve film is plasma-treated and the CoFe / Cu interface is plasma-treated in Example 6 above. A loop (FIG. 14) and an MR curve minor loop (FIG. 15) are shown. 14 and 15, the horizontal axis represents H (Oe) and the vertical axis represents MR (%). In this example, the Ru / CoFe interface is treated for 15 seconds and the CoFe / Cu interface is treated for 30 seconds. According to this example, a high MR ratio of 12%, a low Hin of −4 Oe, and a low Hc of 0.5 Oe were obtained.

  Example 9: In Example 10, the bias voltage Vdc applied to the substrate 25 which is a plasma condition in the plasma processing of the Ru / CoFe interface in the manufacturing method of the bottom type spin-valve giant magnetoresistive thin film shown in FIG. The example which changed is shown. According to this embodiment, it can be seen that the lower the bias voltage applied to the substrate 25 is, the lower Hin and the higher MR ratio are obtained.

  In the above-described embodiment and each example, the same effect can be achieved even if the Cu layer of the spin valve film is replaced with a so-called TMR film in which an Al oxide layer (AlOx layer) is replaced. Since the TMR film has a higher MR ratio than the GMR film, it is a magnetic multilayer film that is attracting attention as a next-generation magnetic reproducing head, and is also promising as a next-generation nonvolatile memory.

  In the embodiments and examples described above, when the laminated ferrimagnetic pinned layer is a multilayer film in which a nonmagnetic layer sandwiched between a magnetic layer and a magnetic layer is composed of two or more types of layers, nonmagnetic It is preferable to perform plasma treatment on at least one of the interfaces existing in the layer. Further, when the magnetization free layer is a multilayer film composed of two or more types of layers, it is preferable to perform plasma treatment on at least one of the interfaces existing in the magnetization free layer. Furthermore, when the antiferromagnetic layer is a multilayer film composed of two or more kinds of layers, it is preferable to perform plasma treatment on at least one of the interfaces existing in the antiferromagnetic layer.

  In the above-described embodiment, the plasma processing chamber 14 is specially used in the multi-chamber film forming apparatus 10 in order to perform plasma processing at an appropriate stage during the film formation of the multilayer structure of the spin valve type giant magnetoresistive thin film. However, the present invention is not limited to this. For example, the parallel-plate electrode structure shown in FIG. 2 or an ion irradiation structure may be provided in the film forming chambers 13A and 13B, and the plasma treatment may be performed in the film forming chamber.

  In the method of manufacturing a spin valve giant magnetoresistive thin film according to the present invention, the plasma treatment is performed on the predetermined interface selected as described above in the multilayer structure of the spin valve giant magnetoresistive thin film, thereby flattening and cleaning the interface. As a result, a high MR ratio is realized. However, in the multilayer structure, any one of all interfaces existing between the buffer film and the protective film, or any combination thereof is used. Of course, the effects of the present invention can be realized by plasma processing all the interfaces.

  In the above description, the invention has been explained only by grasping the invention from the viewpoint of the manufacturing method of the spin valve type giant magnetoresistive thin film, but the multilayer of the spin valve type giant magnetoresistive thin film made by the manufacturing method according to the present invention has been explained. The film structure itself has a unique film structure in which a predetermined interface is flattened and cleaned by plasma treatment or the like.

The multi-chamber apparatus according to the present invention realizes the following manufacturing method.

A first manufacturing method is a multilayer comprising a buffer layer deposited on a substrate, a nonmagnetic conductive layer, a magnetization fixed layer sandwiching the nonmagnetic conductive layer, a magnetization free layer, and an antiferromagnetic layer formed adjacent to the magnetization fixed layer. A spin valve type giant magnetoresistive thin film comprising a protective layer and a protective layer deposited on the uppermost layer, wherein at least one of a plurality of interfaces formed between the nonmagnetic conductive layer and the buffer layer This is a method of plasma-treating the portion. In this spin valve type giant magnetoresistive thin film manufacturing method, a plurality of interfaces formed below the nonmagnetic conductive layer are appropriately subjected to plasma treatment, thereby improving the flatness and cleanliness of each layer. High MR ratio and low Hin are enabled.

The second manufacturing method is preferably the above-described first manufacturing method, wherein the magnetization fixed layer is formed on the substrate side and the magnetization free layer is formed on the protective layer side in the multilayer part, and the magnetization fixed layer and / or The magnetization free layer is formed of a single layer or a plurality of layers, and is characterized in that at least one of a plurality of interfaces formed between the nonmagnetic conductive layer and the buffer layer is subjected to plasma treatment. This method is a manufacturing method of a bottom type spin valve type giant magnetoresistive thin film.

The third manufacturing method is preferably the first manufacturing method, wherein the magnetization free layer is formed on the substrate side and the magnetization fixed layer is formed on the protective layer side in the multilayer part, and the magnetization fixed layer and / or Alternatively, the magnetization free layer is composed of a single layer or a plurality of layers, and plasma treatment is performed on at least one of a plurality of interfaces formed between the nonmagnetic conductive layer and the buffer layer and a plurality of interfaces in the magnetization fixed layer. It is characterized by. This method is a manufacturing method of a top type spin valve type giant magnetoresistive thin film.

In the first manufacturing method according to the fourth manufacturing method, preferably, in the multilayer portion, the magnetization fixed layer includes a lower magnetization fixed layer and an upper magnetization fixed layer, and the nonmagnetic conductive layer is a lower nonmagnetic conductive layer. A five-layer structure including a lower magnetization fixed layer and a magnetization free layer sandwiching the lower nonmagnetic conductive layer, and a magnetization free layer and an upper magnetization fixed layer sandwiching the upper nonmagnetic conduction layer. And at least one of the lower magnetization fixed layer, the upper magnetization fixed layer, and the magnetization free layer is formed of a single layer or a plurality of layers, and is formed between the lower nonmagnetic conductive layer and the buffer layer. Plasma treatment is performed on at least one of the plurality of interfaces and the interface between the upper nonmagnetic conductive layer and the magnetization free layer. This method is a method of manufacturing a dual type spin valve type giant magnetoresistive thin film.

The fifth manufacturing method is a bottom-type spin-valve type giant magnetic layer in which a buffer layer, an antiferromagnetic layer, a magnetization fixed layer, a nonmagnetic conductive layer, a magnetization free layer, and a protective layer are sequentially laminated on a substrate. A method of manufacturing a resistance thin film, wherein a plasma treatment is performed on at least one of an interface between a buffer layer and an antiferromagnetic layer, an interface between an antiferromagnetic layer and a magnetization fixed layer, and an interface between a magnetization fixed layer and a nonmagnetic conductive layer It is.

  In a sixth manufacturing method according to the fifth method described above, preferably, the magnetization fixed layer has a three-layer structure of a first magnetization fixed layer element and a second magnetization fixed layer element separated by a nonmagnetic layer. This is a ferrimagnetic pinned layer, an interface between the antiferromagnetic layer and one pinned layer, an interface between the first pinned layer element and the nonmagnetic layer, an interface between the nonmagnetic layer and the second pinned layer element, and the second pinned magnetization. Plasma treatment is performed on at least one of the interfaces between the layer element and the nonmagnetic conductive layer.

The seventh manufacturing method is a top-type spin-valve giant magnetic layer in which a buffer layer, a magnetization free layer, a nonmagnetic conductive layer, a magnetization fixed layer, an antiferromagnetic layer, and a protective layer are sequentially laminated on a substrate. This is a method for manufacturing a resistance thin film, in which at least one part of the interface between the buffer layer and the magnetization free layer and the interface between the magnetization free layer and the nonmagnetic conductive layer is plasma-treated.

In an eighth manufacturing method according to the seventh method described above, preferably, the magnetization fixed layer has a three-layer structure including a first magnetization fixed layer element and a second magnetization fixed layer element separated by a nonmagnetic layer. It is a type magnetization fixed layer, and plasma processing is performed on at least one of the interface between the first magnetization fixed layer element and the nonmagnetic layer and the interface between the nonmagnetic layer and the second magnetization fixed layer element.

A ninth manufacturing method includes a buffer layer, a first antiferromagnetic layer, a first magnetization fixed layer, a first nonmagnetic conductive layer, a magnetization free layer, a second nonmagnetic conductive layer, a second magnetization fixed layer on a substrate, A method of manufacturing a dual-type spin-valve giant magnetoresistive thin film that is successively laminated in the order of a second antiferromagnetic layer and a protective layer, the interface between the buffer layer and the first antiferromagnetic layer, the first antiferromagnetic layer In this method, at least one of the interface between the magnetic layer and the first magnetization fixed layer, the interface between the first magnetization fixed layer and the first nonmagnetic conductive layer, and the interface between the magnetization free layer and the second nonmagnetic conductive layer is plasma-treated. .

In a tenth manufacturing method according to the ninth method, preferably, the first magnetization fixed layer has a three-layer structure including a first magnetization fixed layer element, a first nonmagnetic layer, and a second magnetization fixed layer element. A laminated ferri, a second laminated ferrimagnetic structure in which the second magnetization fixed layer has a three-layer structure of a third magnetization fixed layer element, a second nonmagnetic layer, and a fourth magnetization fixed layer element, and the first antiferromagnetic layer And the first magnetization fixed layer element, the interface between the first magnetization fixed layer element and the first nonmagnetic layer, the interface between the first nonmagnetic layer and the second magnetization fixed layer element, the second magnetization fixed layer element and the first nonmagnetic layer Plasma processing is performed on at least one of the interface of the magnetic conductive layer, the interface between the third magnetization fixed layer element and the second nonmagnetic layer, and the interface between the second nonmagnetic layer and the fourth magnetization fixed layer element.

The eleventh manufacturing method is preferably a multilayer film in which the buffer layer is composed of two or more types of layers in each of the manufacturing methods described above, and plasma is applied to at least one of a plurality of interfaces existing in the buffer layer. It is characterized by processing.

A twelfth manufacturing method is the above-described manufacturing method, preferably, the plasma treatment is similar to Ar, Kr, Xe, Ne, or the like, which is an inert gas having a low pressure of 0.01 to 100 Pa. A plasma using a 13.56 MHz RF wave is used in a gas atmosphere of any of the gases, and the electrode structure is a parallel plate capacitive coupling type.

In the thirteenth manufacturing method, in the twelfth manufacturing method, preferably, a substrate to be subjected to plasma processing is disposed on an electrode on the side to which an RF wave is applied in an electrode structure, and the electric power by the RF wave is 0 per unit area. .5W / cm ² Hereinafter, the bias voltage applied to the substrate is a voltage included in a range of less than 0V and −300V or more.

In the twelfth manufacturing method, the fourteenth manufacturing method is preferably characterized in that the processing time of the plasma processing is a time not exceeding 1 minute.

In the method for producing a spin valve type giant magnetoresistive thin film by the multi-chamber film forming apparatus of the present invention, the film formation is temporarily interrupted during the film formation of the multi-layered spin valve film, and the interface is subjected to ion bombardment treatment, preferably plasma treatment. And then the film formation is resumed. In this manufacturing method, the plasma treatment is not necessarily performed in the film forming chamber, and may be performed by moving to another vacuum chamber via an adjacent vacuum chamber or a vacuum transfer chamber.

In the manufacturing method using the multi-chamber film forming apparatus of the present invention, the Cu layer is used for the nonmagnetic conductive layer regardless of the structure of the spin valve film such as the bottom type, the top type, and the dual spin valve, and the film thickness of the Cu layer. When 2.1 is set to 2.1 nm, the bottom type, the top type, and the dual type so that the interlayer coupling magnetic field (Hin) between the magnetization fixed layer and the magnetization free layer via the Cu layer is the smallest and the MR ratio is the largest. In accordance with the spin valve film structure of the spin valve, an interface for performing plasma processing or the like is appropriately selected. The interruption of the film formation by the plasma treatment is not necessarily limited to once, and may be performed a plurality of times as necessary.

Furthermore, in the manufacturing method using the multi-chamber film forming apparatus of the present invention, the plasma processing conditions (RF power, processing time, Ar pressure, etc.) are changed depending on the material used for the plasma processing layer, Hin is small, MR The ratio is increased. Further, the manufacturing method using the multi-chamber film forming apparatus of the present invention is characterized in that no process using oxygen or oxidation process is used.

Carrying out the production method of the scan pin valve type giant magnetoresistive film is a plan view of a multi-chamber deposition apparatus according to the present invention. It is a longitudinal cross-sectional view which shows the internal structure of the plasma processing chamber of the film-forming apparatus. It is a figure which shows the laminated structure of the bottom type spin-valve type giant magnetoresistive thin film which is an example of a multilayer film. It is a figure which shows the laminated structure of the top type spin valve type giant magnetoresistive thin film which is an example of a multilayer film. It is a figure which shows the laminated structure of the dual type spin valve type giant magnetoresistive thin film which is an example of a multilayer film. FIG. 5 is a characteristic diagram showing the dependency of the interface for plasma processing in the bottom type spin valve type giant magnetoresistive thin film according to the first embodiment of the present invention. FIG. 10 is a characteristic diagram showing the dependency of the interface for plasma processing in a top type spin valve giant magnetoresistive thin film according to the second embodiment of the present invention. FIG. 9 is a characteristic diagram showing the dependency of the Ru / CoFe interface on the plasma processing time in a bottom type spin-valve giant magnetoresistive thin film according to the third embodiment of the present invention. It is a characteristic view which shows 4th Example of this invention and shows the interface dependence of a dual type spin valve type giant magnetoresistive thin film. FIG. 10 is a characteristic diagram showing the dependency of the CoFe / Cu interface on the plasma processing time in a bottom type spin-valve giant magnetoresistive thin film according to the fifth embodiment of the present invention. FIG. 10 is a characteristic diagram showing a comparison of MR curves in the case of a standard type of a bottom type spin-valve type giant magnetoresistive thin film, NOL, and with plasma treatment according to a sixth embodiment of the present invention. FIG. 7 shows a seventh embodiment of the present invention, in the case of no plasma processing in a bottom type spin-valve giant magnetoresistive thin film, when NOL is inserted, when Ru / CoFe interface is plasma-treated, and Ru / CoFe interface FIG. 5 is a characteristic diagram showing the dependence of the MR ratio on the Cu layer thickness when the CoFe / Cu interface is plasma treated. FIG. 7 shows a seventh embodiment of the present invention, in the case of no plasma processing in a bottom type spin-valve giant magnetoresistive thin film, when NOL is inserted, when Ru / CoFe interface is plasma-treated, and Ru / CoFe interface It is a characteristic view which shows the Cu layer thickness dependence of Hin at the time of plasma-processing the CoFe / Cu interface. The characteristic diagram which shows 8th Example of this invention, and shows the MR curve major loop when the Ru / CoFe interface is plasma-treated in the bottom type spin-valve giant magnetoresistive thin film and when the CoFe / Cu interface is plasma-treated It is. The characteristic diagram which shows 8th Example of this invention and shows the MR curve minor loop when the Ru / CoFe interface is plasma-treated in the bottom type spin-valve giant magnetoresistive thin film and when the CoFe / Cu interface is plasma-treated It is. The characteristic view which shows 9th Example of this invention and shows the dependence of the bias voltage Vdc to the board | substrate which is a plasma condition in the plasma processing of the Ru / CoFe interface in the manufacturing method of a bottom type spin-valve type giant magnetoresistive thin film It is. It is sectional drawing which shows an example of the laminated structure of a bottom type spin-valve type giant magnetoresistive thin film. It is sectional drawing which shows an example of the laminated structure of a top type spin valve type giant magnetoresistive thin film. It is sectional drawing which shows an example of the laminated structure of a dual type spin-valve type giant magnetoresistive thin film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Film-forming apparatus 11 Substrate transfer robot 12 Vacuum transfer chamber 13A, 13B Film-forming chamber 14 Plasma processing chamber 15 Load lock chamber 21 Vacuum tank 22 Upper electrode 23 Lower electrode 25 Substrate 26 Plasma 31, 32 Target 41 Buffer layer 42 Antiferromagnetic Layer 43 Magnetization fixed layer 44 Nonmagnetic conductive layer 45 Magnetization free layer 47 Protective layer

Claims (4)

Vacuum transfer chamber including a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited antiferromagnetic layer and the magnetization fixed layer, and, coupled to the vacuum transfer chamber is arranged, has a pulp plasma processing chamber to generate a plasma of inert gas,
The substrate transfer robot, the substrate, the first carried into the deposition chamber, said after completion of film formation of the antiferromagnetic layer in the first film forming chamber, the plasma was carried out from the first film forming chamber was loaded into the process chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the first film formation chamber, the deposition termination of the magnetization fixed layer in the first film forming chamber Thereafter, the multi-chamber film forming apparatus is carried out from the first film forming chamber. Vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in the vacuum transfer chamber, the first film forming chamber you deposited antiferromagnetic layer and the magnetization fixed layer, coupled arranged in the vacuum transfer chamber , second film forming chamber for forming the non-magnetic conductive layer or an oxide layer, and, coupled arranged in the vacuum transfer chamber, having a pulp plasma processing chamber to generate a plasma of inert gas,
The substrate transfer robot, the substrate, the first carried into the deposition chamber, said after completion of film formation of the antiferromagnetic layer in the first film forming chamber, the plasma was carried out from the first film forming chamber was loaded into the process chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the first film formation chamber, the deposition termination of the magnetization fixed layer in the first film forming chamber after, the first and unloaded from the deposition chamber were carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the second film forming chamber, said after completion of film formation of the non-magnetic conductive layer or an oxide layer at a second deposition chamber, multi-chamber deposition apparatus, characterized in that for unloading from the second film formation chamber. Vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited buffer layer and the antiferromagnetic layer, and, coupled arranged in the vacuum transfer chamber is has a Help plasma processing chamber to generate plasma of the inert gas,
The substrate transfer robot, the substrate, the first carried into the deposition chamber, said after completion of film formation of the first buffer layer in the film forming chamber, the plasma processing chamber and unloaded from the first film forming chamber carried in, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the first film forming chamber, after antiferromagnetic layer forming the end of the in the first film forming chamber , a multi-chamber deposition apparatus, characterized in that for unloading from the first film forming chamber. Vacuum transfer chamber having a substrate transfer robot for moving the substrate, coupled arranged in said vacuum transfer chamber, the first film forming chamber you deposited the magnetization free layer, coupled arranged in the vacuum transfer chamber, the buffer layer, and , second film forming chamber you deposited nonmagnetic conductive layer or an oxide layer, and, coupled arranged in the vacuum transfer chamber, having a pulp plasma processing chamber to generate a plasma of inert gas,
The substrate transfer robot, the substrate, the second is loaded into the deposition chamber, said after completion of film formation of the second buffer layer in the film forming chamber, the plasma processing chamber and unloaded from the second film formation chamber carried in, after the plasma treatment completion in the plasma processing chamber, said plasma processing chamber and unloaded from the carried into the first film forming chamber, after completion of film formation of the magnetization free layer in the first film forming chamber, and unloaded from the first film forming chamber is carried into the plasma processing chamber, after the plasma treatment completion in the plasma processing chamber, and unloaded from the plasma processing chamber is carried into the second film forming chamber, the second after completion formation of the non-magnetic conductive layer or an oxide layer in the film forming chamber, multi-chamber deposition apparatus, characterized in that for unloading from the second film formation chamber.

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