WO1998015668A1 - Production method of laminate body, and the laminate body - Google Patents

Abstract

A method for producing a low-cost laminate comprising a functional thin film. More concretely, a substrate is irradiated with an ion beam in an atmosphere containing different kinds of vaporized materials so as to deposit different materials one on another.

Description

 Specification

 Laminated body manufacturing method and laminated body technical field

 The present invention relates to a functional member having a structure in which two types of thin films having different characteristics are alternately laminated, and in particular, to a superlattice giant magnetoresistive film (GMR) in which a magnetic material and a nonmagnetic material are alternately laminated. The present invention relates to a method for manufacturing a laminate that can be applied to the production of materials for films, magnetic materials for CDs, and materials for MOS bonding. Background art

 Conventionally, a structure in which two or more thin films having different characteristics are stacked has been manufactured by forming and depositing a different material for each layer by a method such as vapor deposition or sputtering. For example, Japanese Patent Application Laid-Open No. 5-303724 discloses a method of manufacturing a magnetoresistive film by laminating a magnetic film and a non-magnetic film using a sputtering method and manufacturing a magnetic head of a magnetic disk drive. . The conventional method of manufacturing a laminated film requires a process of changing the type of a substance to be deposited, sputtered, or the like when forming each layer, and has a problem that the manufacturing is time-consuming and costly. Was. In addition, it is technically difficult to form a multilayer while controlling the thickness of one layer accurately on the order of a nanometer, and there has been a problem that the yield is reduced.

An object of the present invention is to provide a method for manufacturing a laminated film capable of forming a plurality of thin films having different characteristics in a short time. Another object of the present invention is to provide a functional thin film laminate in which the thickness of each layer is on the order of nanometers. Disclosure of the invention

 In order to achieve the above object, according to the present invention, while depositing a plurality of different types of atoms or molecules on a substrate, the atoms or molecules on the substrate are irradiated with an ion beam. A method for manufacturing a laminate is provided, wherein the plurality of types of atoms or molecules are laminated on the substrate for each type of atomic or molecular substance.

Methods for depositing different types of atoms or molecules on a substrate include, for example, heating a metal or ceramic in a crucible by irradiating it with an electron beam to vaporize or regenerate by sputtering. A method of depositing the deposited atoms or molecules on the substrate or a so-called CVD method using a reactive gas and depositing the reactive gas in contact with the substrate can be used. When a vapor containing a plurality of different substances is deposited on a substrate by an ordinary method, each substance condenses to form a two-dimensional island-like layer in the direction of the surface of the substrate. The inventors deposit atoms or molecules on a substrate and irradiate with an ion beam to separate a plurality of types of substances, and obtain a structure in which each atom or molecule is laminated for each type of substance. I found that I can do it. This principle is based on forces that are not clearly understood at present. With the usual method of depositing atoms or molecules, the atoms or molecules cannot move after the atoms or molecules come into contact with the substrate. Therefore, atoms or molecules that are partially agglomerated while the atoms or molecules are floating in the reaction vessel are deposited as they are, so they are deposited in a two-dimensional island shape and solidified as they are. Here, by irradiating the ion beam before the atoms or molecules are solidified to give energy to a substance existing on the substrate, energy for movement is given to atoms constituting the substance. Each substance is a single layer Is more energy stable, and a uniform temperature region is formed in a direction parallel to the substrate surface. Therefore, a plurality of substances are formed as layers parallel to the substrate surface having a single composition. If more than 10 atomic layers of atoms or molecules are deposited on the substrate, the lowermost atomic layer is solidified and cannot be rearranged even if energy is subsequently applied by an ion beam. Therefore, it is necessary to irradiate an ion beam with sufficient energy before the atoms or molecules deposited on the substrate are deposited in 10 atomic layers. Specifically, it is possible to control the film structure and film thickness of the formed laminate by adjusting the energy density of the ion beam, the temperature of the substrate forming the laminate, the amount of each substance in the vapor, and the like. it can. The ion beam may be provided with energy for moving and rearranging the substance on the substrate, and the type of ions may be oxygen, nitrogen, or an inert gas (argon, xenon, etc.). The material forming the laminate can be a reactive gas used for vaporization, sputtering, or CVD by electron beam heating, as used in conventional thin film forming techniques.

 With the above configuration, it becomes possible to produce a thin film of the order of nanometers faster and at lower cost than in the case of producing a laminated body by sputtering different materials. In addition, since the manufactured film has little crystal disorder, it also has characteristic characteristics such as a small decrease in magnetic characteristics.

 In the above, it is preferable that the number of atoms or molecules to be deposited per unit time is 1 to 100 with respect to the number of ions per unit time 1 of the ion beam irradiating the atoms or molecules on the substrate. . As described above, this is a desirable condition for rearrangement before the atoms to be deposited become more than 10 atomic layers and solidify.

Methods for depositing atoms or molecules include vapor deposition or sputtering. It is preferable that it is used. A certain degree of vacuum is required as conditions for ion beam irradiation. Since vapor deposition and sputtering can be performed most efficiently with the same degree of vacuum, this is a suitable combination for implementing the present invention in the same reaction vessel.

 The ion beam is preferably a beam composed of at least one kind of ion selected from oxygen, nitrogen and argon. It is a gas species that is inexpensive and is suitable for applying energy to atoms or molecules on a substrate.

 In the above configuration, at the time of the ion beam irradiation, by changing the atomic volume ratio of each of the substances alone, it is possible to change the thickness of each of the alternately stacked separated phases in proportion to the substance concentration. it can.

 Further, in the above structure, a laminated structure of metal and ceramics can be manufactured by using at least one kind of substance as a metal and the other kind as a ceramic.

 In the case of using the sputtering method, since the sputtering rate of ceramics is lower than that of metal, it was technically difficult to form a laminate of ceramics and metal with the same thickness, and the process was time-consuming. . By using the method of the present invention, it is possible to easily produce a mixed laminate of ceramics and metal in a short time.

 In the above structure, at least one kind of the substance is made of a magnetic material, and the other kind is made of a non-magnetic material, so that a laminated structure of a single-domain magnetic layer and a non-magnetic layer can be obtained.

Attention has been focused on a method of manufacturing functional thin films such as giant magnetoresistive films by laminating magnetic and non-magnetic materials in multiple layers. If such a film is manufactured using the conventional method, it takes a long time to manufacture the film because of the multilayer structure. In addition, there were problems such as crystal disorder in each layer, and insufficient magnetic properties.

 By using the method of the present invention, it is possible to produce a laminated film with little crystal disorder in a short time.

 Also, at least one of the plurality of substances may be a magnetic material, another one may be an insulating material, and the other one may be a conductive metal material. In the present invention, the configuration, thickness, and the like of each layer can be easily changed as appropriate according to the application.

In the above configuration, each substance is preferably a substance that does not dissolve in a liquid phase or a solid phase. In the present invention, a substance once attached to a substrate is irradiated with an ion beam to relocate the substance. If each material is easily dissolved in each other during the rearrangement, there is a possibility that an intermediate layer diffuses between the layers. Therefore, the material forming the respective layers by be produced by a method of low solubility substance is is preferably _c present invention each other, laminate structure as One if such obtained were manufactured in a conventional manner and can be produced Become. For example, three or more layers of two types of substances are alternately stacked on a substrate, and the substance grows in a columnar direction in a direction perpendicular to the substrate, and a gap between the substances growing in a columnar form evaporates. It is possible to produce a laminate that is filled with a modified material.

 In the above laminate, the thickness of each layer can be set to 1 μm or less.

 It is desirable that each material of the above-mentioned laminate satisfy the following formula, where f i represents the atomic volume ratio of a single substance.

 ∑f i = 1

And

 0. 2 2≤fi≤ 0. 7 8

Also, the substance may be a small one of them may be a crystalline material _t Further, in the above crystalline material, it is preferable that the closest atomic plane is a lamination plane.

 In the crystalline material, twins may be formed without disturbing the stacking of the closest atomic plane. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a diagram showing an example of an apparatus for carrying out the present invention.

 FIG. 2 is a diagram showing a method for controlling a deposition amount according to the first embodiment of the present invention.

 FIG. 3 is a diagram showing the composition distribution of the laminated film manufactured in Example 1 of the present invention.

 FIG. 4 is a view showing a typical example of the structure of the laminated film of the present invention. FIG. 5 shows a transmission electron micrograph of the laminated film of the present invention observed from above.

 FIG. 6 shows a lattice image of the laminated film according to Example 1 of the present invention, taken by a transmission electron microscope.

 FIG. 7 is a diagram showing a magnetic head assembly of a magnetic disk recording device to which the laminated film of the present invention is applied.

 FIG. 8 is a cross-sectional view of a thin-film magnetic head to which the laminated film of the present invention is applied. BEST MODE FOR CARRYING OUT THE INVENTION

 (Example 1)

A laminate of the present invention was formed on the surface of the substrate using polycrystalline pure copper by a film forming apparatus shown in FIG. This film deposition system is installed in a vacuum vessel 101. The installed ion source 102, electron gun 103, evaporation crucible 104 capable of storing a plurality of evaporation materials, sample holder 105, and vacuum vessel 101 have a vacuum degree of 10- ^ε Torr or less. It is composed of a vacuum pump 106 which can be evacuated. The shape of the test piece is a 20 × 40 × 3 band-shaped plate. First, the surface of the test piece was mirror-polished, degreased and washed, and then attached to the sample holder 105 in the vacuum vessel 101. Then after evacuating the vacuum vessel 1 0 1 below 5 1 0- ⁶ Torr by a vacuum pump 1 0 6, the ion source 1 0 2 with an acceleration voltage 1 0 k V, Shi pull out electrode current density 1.5 The substrate surface was cleaned by irradiating with oxygen ion for 10 minutes under the condition of mA / cm ² . Thereafter, while continuing the ion source 1 0 2 or et oxygen ion irradiation in the conditions, by irradiating an electron beam from an electron gun 1 0 3 to C u and A 1 ₂ 0 ₃ placed in the deposition crucible 1 04 heated, it was co-deposited C u and a 1 ₂ 0 ₃ by electron beam evaporation method. C u and A 1 ₂ 0 ₃ is their respective evaporated from separate crucibles, were also controlled independently deposited amount. Time control of the deposition amount starts deposited as shown in FIG. 2 only as C u, increasing the deposition amount of A 1 ₂ 〇 ₃ while gradually decreasing the deposition amount of C u, eventually

It was controlled that deposition only A 1 _z 0 _3. Note deposition rate of the deposition starting C u is 1 0 μ πι /], deposition rate of A 1 ₂ 0 ₃ at the end of vapor deposition is set to 1 0 μ πι Zh, film formation was carried out for 6 0 min. Thus, to form a mixed film composition C u having a thickness of about 1 Ο μ πι and A 1 ₂ 0 ₃ has a continuous change on the substrate. For comparison, the mixed film was formed only by vapor deposition without irradiation with oxygen ions.

Elemental analysis of the cross section of the sample prepared in this manner was performed by EPMA, and as a result, a film formed while performing oxygen ion irradiation according to the present invention and a film formed without performing oxygen ion irradiation as a comparative material were formed. the C u 1 0 0-0% by either toward the surface from the substrate as shown in FIG. 3 of the sample, a 1 ₂ 〇 ₃ 0 The composition distribution was such that the composition continuously changed to about 100%. Furthermore, the cross-sectional microstructures of these samples were observed with a TEM (transmission electron microscope). In the sample formed while performing oxygen ion irradiation according to the present invention, Cu:

A 1 ₂ 〇 ₃ composition ratio is 1 0: 0 to 5: alternately laminated in five areas C u and A 1 ₂ 〇 ₃ Guys Re also a thickness of several tens of nm from several nm single crystal phase It was an organization. FIG. 4 is a schematic view of a typical example of such a laminated structure, and FIG. 5 is a transmission electron micrograph observed from above the laminated body. Figure 6 is C u: A 1 ₂ 0 ₃ composition ratio of 8: 1 0~ 2 0 nm A 1 2 0 3 is alternating C u and 3 to 5 mu m thick lattice image of the two near the It is a laminated structure. On the other hand, the comparative material had a structure in which the particles were dispersed in a matrix form over the entire composition region, and such a laminated structure was not observed.

 (Example 2)

A single crystal Si wafer was used as a substrate, and a laminate of the present invention was formed on the surface thereof by a film forming apparatus shown in FIG. This film-forming apparatus is an ion source 102, an electron gun 103, a deposition crucible 104 capable of storing a plurality of deposition materials, a sample holder 105, and a vacuum installed in a vacuum vessel 101. The container 101 includes a vacuum pump 106 capable of evacuating the container 101 to a degree of vacuum of 10 Torr or less. The specimen shape is a disk with a diameter of 25.4 x 1 mm. First, the surface of the test piece was degreased and washed, and then attached to the sample holder 105 in the vacuum vessel 101. Then after evacuating the vacuum vessel 1 0 1 below 5 X 1 0- ⁶ Torr by a vacuum pump 1 0 6, the ion source 1 0 2 0 accelerating voltage 1 with k V, pull out Shi electrode current density 1. the 5 m a ZCM oxygen ions in the ^second condition was cleaning of the irradiated surface of the substrate for 10 minutes. Thereafter, while continuing the ion source 1 0 2 or et oxygen ion irradiation in the conditions, is irradiated with an electron beam from an electron gun 1 0 3 were placed in the vapor deposition crucible 1 0 4 C o and A 1 ₂ O _a And heat, e-bee Ri was co-deposition of C o and A 1 ₂ 0 ₃ by the beam vapor deposition method. C o and _A l ₂ 0 _a is their respective evaporated from separate crucibles, were also controlled independently deposited amount. Control of the deposition amount C o: 6 μ / h, A 1 2 0 3: was about 1 2 minute deposition constant at 4 MZH. Thus, to form a C o and mixed film of A l ₂ 〇 ₃ having a thickness of about 2 / m on a single crystal S i Uweha substrate. For comparison, the mixed film was formed only by vapor deposition without irradiation of oxygen ions.

Elemental analysis of the cross section of the sample prepared in this manner was performed by EPMA. As a result, the sample formed while performing oxygen ion irradiation according to the present invention and the sample formed as a comparative material without performing oxygen ion irradiation were used. 6 0% none was C 0 of the sample, a 1 ₂ 0 ₃ is was observed segregation at 4 0% composition. Furthermore, the cross-sectional microstructures of these samples were observed with a TEM (transmission electron microscope). In the sample formed while performing oxygen ion irradiation according to the present invention, C o and

A has been a tissue of alternately laminated with 1 ₂ 0 ₃ is a thickness of several tens of nm from several nm in both a single crystal phase. On the other hand, the comparative material had a structure in which particles were dispersed in a matrix in an island manner over the entire composition range, and such a laminated structure was not observed.

 (Example 3)

A method for manufacturing a giant magnetoresistive film for a thin-film magnetic head for reading and writing magnetic recording of a magnetic head assembly used in a magnetic disk recording device as shown in FIG. 7 by using the present invention. Will be described. The superlattice giant magnetoresistive film is formed by laminating several layers of ferromagnetic material such as cobalt and nonmagnetic material such as copper to increase the resistance change when a magnetic field is detected. Fig. 8 shows a cross-sectional view of the thin-film magnetic head. As shown in FIG., A l ₂ 〇 ₃ is a wear-resistant ceramics - to form a substrate protective layer on the T i C ceramics substrate, a lower shield film thereon, forming a lower gap layer. under A giant magnetoresistive film (GMR film) in which four layers of copper, a non-magnetic material, and cobalt, a ferromagnetic material, are alternately formed in four layers under the magnetic recording reading part of the head gap film. To form A Ni—Fe film, which is a hard magnetic film, is formed on portions other than the lower portion of the upper core. In addition, a terminal, an upper gap film, an upper shield film, a light gap film, and an upper core were formed to produce a recording head. In forming the giant magnetoresistive film (GMR film), the film forming apparatus shown in FIG. 1 was used in the same manner as in Example 1. Acceleration voltage 1 0 k V, the extraction electrode current density 1.5 after the oxygen ions were click re-learning of 1 0 minute irradiation shines substrate surface under conditions of mAZcm ^2, oxygen ions from the ion source at the conditions With the irradiation continued, Co and Cu placed in the evaporating crucible 104 were irradiated with an electron beam from the electron gun 103 and heated, and simultaneously Co and Cu were deposited by electron beam evaporation. Evaporated. Co and Cu were evaporated from separate crucibles, and the deposition rates were controlled independently. Control of the deposition amount C o: 4 μ m / h , A 1 2 0 3: was about 5 minutes deposited constant at S ^ MZH. In this way, a film was formed in which Co having a thickness of about 4 nm and Cu having a thickness of 2 nm were alternately laminated in five layers. When the cross-sectional structure of this film was observed by TEM, almost no disorder was observed in the crystal structure at the boundary layer of the film, and good magnetic properties were obtained.

 (Example 4)

The laminated body of the present invention was formed on the surface of a glass disk of 3.5 inches in diameter and 0.5 in thickness by the film forming apparatus shown in FIG. First, the specimen surface was degreased and washed, and then attached to the sample holder 105 in the vacuum vessel 101. Then after evacuating the vacuum vessel 1 0 1 below 5 X 1 0- ⁶ Torr by a vacuum pump 1 0 6, the acceleration voltage 1 0 k V using an ion source 1 0 2, lead-out electrode current density 1. 5 mAZcm Irradiate with argon for 10 minutes under the conditions of ² to clean the substrate surface. Leaning was performed. Thereafter, Co and Cr placed in the evaporation crucible 104 were heated by irradiating an electron beam from the electron gun 103 to the Co and Cr, and Co and Cr were co-evaporated by an electron beam evaporation method. C 0 and Cr were each evaporated from separate crucibles, and the deposition amount was controlled independently. The deposition amount was controlled at C o: 6 m / h and C r: 8 mZh, and the film was formed for about 2 minutes. In this way, an underlayer consisting of a mixed film of Co and Cr having a thickness of about 0.3 μιη was formed on the glass substrate. Thereafter, the crucible containing Ta is also irradiated with an electron beam, thereby performing ternary electron beam deposition of Co, Cr, and Ta, an acceleration voltage of 10 kV, and an extraction electrode current density. The film was irradiated with argon ions for 12 minutes under the condition of 1.5 mA / cm ² to form a magnetic film composed of a laminated film composed of Co, Cr, and Ta. In the magnetic film, the deposition amount of Co was increased so that a ferromagnetic film was formed. The formed ferromagnetic film was a columnar crystal grown in a direction perpendicular to the glass substrate. Such columnar ferromagnetic films are suitable for perpendicular magnetic recording type magnetic disks and magneto-optical disks. According to the present invention, a perpendicular magnetic recording type magnetic disk and magneto-optical disk can be manufactured in a short time.

 (Example 5)

The present invention is realized by a film forming apparatus shown in FIG. 1 on a substrate in which an MS wafer is formed by doping trivalent and pentavalent impurity atoms on a Si wafer substrate having a diameter of 2 inches and a thickness of 1 mm. Was formed. Acceleration voltage 1 0 k V using an ion source 1 0 2 in the semiconductor forming process also went the same vacuum chamber 1 0 1 (degree of vacuum 5 X 1 0- ⁵ Torr or less), the extraction electrode current density 1. While irradiating nitrogen ions under the condition of 5 mAZ cm ² , A 1 N and Cu placed in the evaporating crucible 104 are heated by irradiating an electron beam from the electron gun 103 with the electron beam evaporation method. A 1 N and Cu were simultaneously vapor-deposited. A 1 N and Cu respectively These were evaporated from separate crucibles and the amount of evaporation was controlled independently. The deposition rate was kept constant at A 1 N: 6 m / h and Cu 8 μm / h, and the film was formed for about 12 minutes. Thus, an insulating film made of a mixed film of A1N and Cu having a thickness of about 2 μm was formed on the Si semiconductor substrate. The formed insulating film was columnar crystals perpendicular to the substrate surface.

 Some MOS transistors used for power control raise the operating temperature to about 200 ° C. In such a case, the insulating film on the element peels or cracks due to thermal stress. It is feared that problems such as intrusion may occur. When the insulating film is made of a columnar crystal as in the present invention, it is possible to provide a semiconductor element which is not easily cracked by thermal stress and has high reliability even when used for a long time.

Claims

The scope of the claims  1. While depositing a plurality of different atoms or molecules on a substrate, irradiating the atoms or molecules on the substrate with an ion beam to convert the plurality of types of atoms or molecules onto the substrate. A method for manufacturing a laminate, comprising laminating each type of molecular substance.  2. The method according to claim 1, wherein the number of ions or molecules to be deposited per unit time is 1 to 10 with respect to the number of ions per unit time 1 for irradiating the atoms or molecules on the substrate. 0. A method for producing a laminate, which is 0.  3. A method for producing a laminate, wherein the atoms or molecules according to claim 1 are deposited or sputtered.  4. A method for manufacturing a laminate, wherein the ion beam according to claim 1 is a beam comprising at least one ion selected from oxygen, nitrogen and argon.  5. The method according to claim 1, wherein the thickness of each of the alternately stacked separated phases is changed in proportion to the substance concentration by changing an atomic volume ratio of each of the substances at the time of the ion beam irradiation. A method for manufacturing a laminate, comprising:  6. The method of manufacturing a laminate according to claim 1, wherein at least one of the substances is a metal and the other is a ceramic, and a laminated structure of the metal and the ceramics is produced.  7. The method for manufacturing a laminate according to claim 1, wherein at least one of the substances is a magnetic material, and the other is a nonmagnetic material, and a laminated structure of a single magnetic domain magnetic layer and a nonmagnetic layer is provided. 8. The laminate according to claim 1, wherein at least one of the plurality of substances is in the laminate. One type is a magnetic material, the other type is an insulating material, and the other type is a conductive metal material, and has a three-layer structure of a magnetic layer, an insulating layer, and a conductive layer. Laminate manufacturing method.  9. The method for producing a laminate according to claim 1, wherein the substances are substances that do not dissolve in a liquid phase or a solid phase. 1 0. has a plurality of types of material on a substrate by laminating alternately three or more layers, and a laminate stacked face of the laminate characterized in that it is a close-packed plane of the crystal of the material ₍ 11. The laminate according to claim 10, wherein the laminate comprises an aggregate of columnar crystals grown in a direction perpendicular to the substrate.  12. A laminate, wherein the gaps between the columnar crystals according to claim 11 are filled with an evaporated substance.  13. The laminate according to claim 10, wherein the thickness of each laminated surface of the laminate according to claim 10 is 1 μm or less.  14. The laminate according to claim 10, wherein each of the substances according to claim 10 satisfies the following expression, where fi is the atomic volume ratio of a single substance.  ∑fi = 1 And  0.2 2 ≤ fi ≤ 0.7 8  15. The laminate according to claim 10, wherein at least one of the substances is a crystalline material.  1 6. The laminate according to claim 15, wherein the twins are formed without disturbing the stacking of the closest atomic plane.