JP3824787B2 - Manufacturing method and manufacturing apparatus of ultrafine particle dispersion film - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method and an apparatus for producing an ultrafine particle dispersion film in which ultrafine particles of various raw materials such as metals, semiconductors and oxides are dispersed in different substances.
[0002]
[Prior art]
An ultrafine particle dispersion film in which ultrafine particles such as Fe and Co are dispersed in Ag, Cu, carbon and the like is manufactured by a phase separation method, a composite vapor deposition method, or the like.
In the phase separation method, a forced solid solution is produced by sputtering, melt quenching, etc. from a plurality of substances having a small amount of solid solution to each other, and the phase separation is promoted in the production stage or the subsequent heat treatment stage, thereby producing ultrafine particles. Has a decentralized organization. In this method, since it is necessary that the dispersed fine particles do not dissolve in the dispersion medium, the kind of ultrafine particle dispersed film that can be produced is limited. Further, the particle size and the amount of dispersion of the dispersed fine particles cannot be controlled independently.
[0003]
On the other hand, in the composite vapor deposition method, a plurality of types of ultrafine particles prepared by the gas evaporation method are introduced into a vacuum chamber and simultaneously vapor deposited on the substrate. Since there is no restriction on the vapor deposition material, the combination of the dispersed fine particles and the dispersion medium can be freely selected, which is suitable for the production of a fine particle dispersion meeting the needs.
In the composite vapor deposition method, a vacuum chamber 3 divided into an evaporation chamber 1 and a vapor deposition chamber 2 is used as shown in FIG.
The evaporation chamber 1 maintains the pressure of the atmospheric gas at about 100 Pa and accommodates the evaporation source 4. The vapor deposition chamber 2 communicates with the evaporation chamber 1 through an ejection hole 5 provided in the partition wall, and a substrate 6 on which ultrafine particles from the evaporation chamber 1 are deposited is disposed. In addition, a second evaporation source 7 is disposed in the vapor deposition chamber 2 in order to deposit a matrix material on the substrate 6. The vapor deposition chamber 2 is maintained at a high vacuum of about 1 Pa by the exhaust pump 8 in order to create a pressure difference with the evaporation chamber 1.
The material disposed in the evaporation source 4 evaporates by high-frequency heating, arc heating, laser heating, sputtering, or the like, and fills the evaporation chamber 1 as ultrafine particles. Then, the pressure difference between the evaporation chamber 1 and the vapor deposition chamber 2 becomes drive energy, and the ultrafine particles are sent into the vapor deposition chamber 2 to be vapor deposited on the substrate 6. At this time, a matrix material different from the ultrafine particles is vaporized in the vapor deposition chamber 2 and co-deposited on the substrate 6 to produce an ultrafine particle dispersed film.
[0004]
[Problems to be solved by the invention]
The driving force for sending ultrafine particles from the evaporation chamber 1 to the vapor deposition chamber 2 depends on the pressure difference between the evaporation chamber 1 and the vapor deposition chamber 2. That is, while the evaporation chamber 1 has a pressure of about 100 Pa, the pressure of the vapor deposition chamber 2 usually needs to be about 1 Pa or less. In order to maintain such differential exhaust conditions, use of the exhaust pump 8 having a large exhaust capacity, reduction in the diameter of the ejection hole 5, and the like are employed.
However, when the diameter of the ejection hole 5 is reduced, the influence of the ultrafine particles adhering to the inner wall of the ejection hole 5 appears greatly, and the flow of ultrafine particles from the evaporation chamber 1 to the vapor deposition chamber 2 becomes unstable. As a result, the amount of ultrafine particles supplied to the substrate 6 varies, and an ultrafine particle dispersed film having stable properties cannot be obtained. In an extreme case, the ejection holes 5 may be clogged with the adhering ultrafine particles, and the operation may be disabled. On the other hand, the use of an exhaust pump having a large exhaust capacity increases the equipment burden and is not a practical solution.
[0005]
[Means for Solving the Problems]
The present invention has been devised to solve such a problem, and by evaporating ultrafine particles and different materials in the same atmosphere and mixing them uniformly, it is deposited on a substrate under stable conditions. An object is to produce an ultrafine particle dispersion film having a constant quality by supplying a vapor flow onto a substrate.
In order to achieve the object of the manufacturing method of the present invention, a plurality of types of steam are generated from a plurality of sputtering sources disposed in the same vacuum chamber, and the one or more first steams are passed through the cylindrical guide portion. In the process of leading to the surface of the substrate, it is condensed into ultrafine particles, diffused and mixed with other vapors sent through the cylindrical guide part, and the diffused and mixed ultrafine particles and other vapors are deposited on the substrate surface. A vapor-deposited film in which ultrafine particles are uniformly dispersed in a matrix generated from the above vapor is formed on the substrate surface.
The apparatus used in this method is arranged in a single vacuum chamber, and a plurality of sputtering sources whose input power is controlled independently, and vapor generated by the first sputtering source is condensed into ultrafine particles to form the same vacuum. And a cylindrical guide that guides the other vapor generated in another sputtering source to the substrate arranged in the same vacuum chamber . When a plurality of vapors pass through the cylindrical guide portion, the ultrafine particles and other atomic vapors are led to the substrate surface as a homogenized gas flow by mutual diffusion.
[0006]
Embodiment
In the present invention, the vacuum chamber 10 is provided with two exhaust systems and a plurality of sputtering sources.
The number of sputter sources is determined according to the ultrafine particles to be dispersed in the ultrafine particle dispersion film to be produced. In FIG. 2, since the ultrafine particle dispersion film made of two kinds of materials is produced, two sputter sources 20, 30 is incorporated. The sputter sources 20 and 30 are not limited to the present invention, but specifically, it is preferable to mount a pipe-like target whose inner surface is sputtered.
In the exhaust system, an oil diffusion pump 41 is used as a high vacuum preliminary exhaust system, and an oil rotary pump 42 is used as a large capacity exhaust system for low vacuum.
[0007]
The material for the ultrafine particles is arranged as the target 21 of the sputtering source 20, and the matrix material is arranged as the target 31 of the sputtering source 30. As the material for the ultrafine particles, although not restricting the present invention, a metal or alloy such as Fe, Co, Fe-Ni, a semiconductor, Si, or the like is used. As the matrix material, a metal or alloy such as Cu or Ag, an Si semiconductor, or the like is used although it does not restrict the present invention. The combination of these materials is freely selected according to the intended use of the ultrafine particle dispersion film.
[0008]
A sputtering gas such as Ar is supplied to each of the sputtering sources 20 and 30 from the gas cylinder 22 via the flow rate adjusting valves 23 and 33. The sputter sources 20 and 30 are connected to individual power sources 24 and 34, respectively, so that the discharge output can be controlled independently.
In vapor deposition, first, the vacuum chamber 10 is evacuated to a sufficiently high vacuum by the oil diffusion pump 41, and then a sputtering gas is introduced, and the respective sputtering sources 20 and 30 are operated. At this time, by adjusting the discharge power supplied to the sputtering sources 20 and 30, the amount of the material knocked out of the targets 21 and 31 is controlled independently. During the operation of the sputtering sources 20 and 30, the oil rotary pump 42 is driven to evacuate the vacuum chamber 10.
[0009]
A gas containing vapor released by sputtering is blown onto the substrate S through the cylindrical guide portion 11. When the gas sent from the sputter sources 20 and 30 passes through the cylindrical guide portion 11, the gas is sufficiently mixed by mutual diffusion to be supplied to the substrate S as a homogeneous mixed gas.
As the cylindrical guide portion 11, for example, a cylinder having an inner diameter of about several centimeters is used so that the resistance to the gas flow is reduced. Since the evaporation zone (sputter sources 20, 30) and the vapor deposition zone (substrate S) communicate with each other via the cylindrical guide portion 11, there is almost no pressure difference in any part of the vacuum chamber 10.
[0010]
As described above, since the vapor deposition proceeds in the vacuum chamber 10 maintained in the same vacuum atmosphere, the vapor deposition material such as ultrafine particles is supplied onto the substrate S in a stable gas flow. Moreover, the ultrafine particles and the vapor of the matrix material are uniformly mixed by the cylindrical guide portion 11 and then supplied to the substrate S. Therefore, an ultrafine particle dispersion film having no quality change due to gas flow fluctuation, composition fluctuation, or the like and having a stable quality over a long period of time is formed on the substrate S.
In addition, since the degree of freedom of combination of the ultrafine particles and the matrix is high, functional thin films corresponding to various applications can be produced. For example, when ultrafine particles such as Fe and Co are dispersed in a matrix such as Ag and Cu, a thin film for a magnetic field sensor utilizing a giant magnetoresistance effect is obtained. In addition, a magnetic recording medium in which ultrafine particles such as Co and Fe-Pt alloy are dispersed in a carbonaceous matrix, a soft magnetic thin film material in which Fe ultrafine particles are dispersed in a Si matrix, and the like are also manufactured.
[0011]
【Example】
Fe was used as the target 21 for ultrafine particles, and Ag was used as the target 31 for the matrix. After evacuating the vacuum chamber 10 to 10 ⁻⁴ Pa, the targets 21 and 31 were sputtered under the following conditions while supplying Ar gas. During sputtering, the atmospheric pressure in the vacuum chamber 10 was maintained at 260 Pa.
In the sputtering source 20, a pipe-like Fe target 21 having an inner diameter of 6 mm and a length of 30 mm was used, the Ar gas flow rate was set to 500 SCCM, and the discharge power was set to a constant value of 500 W. The Fe vapor released from the target 21 was condensed into ultrafine particles having an average particle diameter of 6 nm while being transported by Ar gas.
In the sputtering source 30, a pipe-shaped Ag target 31 having an inner diameter of 20 mm and a length of 30 mm was used, the Ar gas flow rate was set to 500 SCCM, and the discharge power was set to a constant value between 30 and 200 W. Ag released from the target 31 was mixed with Fe ultrafine particles as atomic vapor or cluster vapor. At this time, the mixing ratio of Fe ultrafine particles to Ag vapor could be changed by adjusting the discharge power.
[0012]
Ar gas in which Fe ultrafine particles and Ag vapor were suspended was supplied to the substrate S at a flow rate of 1000 SCCM through the cylindrical guide portion 11 having an internal cross-sectional area of 20 cm ² .
In this way, an ultrafine particle dispersion film having a film thickness of 0.3 μm was deposited on the substrate S. In addition, although the film forming speed varies depending on the composition, the film forming speed of 0.1 nm / sec was obtained in the film in which the amount of dispersion of the Fe ultrafine particles was 40 atomic%. When the cross section of the obtained ultrafine particle dispersion film was observed with an electron microscope, it was a structure in which Fe ultrafine particles were dispersed in an Ag matrix as shown in FIG. The Fe ultrafine particles have a dispersion amount of 18 atomic% and a particle size of approximately 6 nm, which is equal to the particle size of the cluster-like fine particles before being deposited on the substrate S.
Next, the vapor density of Ag was changed by the discharge power input to the sputtering source 30 to produce ultrafine particle dispersion films having various compositions. Then, the influence of the composition change, that is, the amount of dispersed Fe fine particles on the magnetization curve of the ultra fine particle dispersed film was investigated.
The ultrafine particle dispersion film exhibited different magnetization curves depending on the amount of Fe fine particles dispersed as shown in FIG. Especially, the ultrafine particle dispersion film in which the Fe fine particle dispersion amount is 18 atomic% shows superparamagnetism, and it can be seen from this that the Fe ultrafine particles are dispersed without mutual interference.
[0013]
Further, in a film in which the dispersion amount of Fe ultrafine particles is 40 atomic% or less, a particle-like magnetization mechanism is observed, which suggests that aggregation and aggregation of Fe ultrafine particles are not progressing. Assuming a state in which spherical particles are randomly arranged on a plane, it can theoretically be said that when the surface density of the particles occupies about 40% of the plane, the particles start to contact all over. In this regard, 40 atomic% of the ultrafine Fe particles is close to the threshold value. In the thin film produced in this example, the fact that coalescence growth is not observed in the Fe ultrafine particles up to the limit density indicates that the Fe ultrafine particles are randomly deposited and immobilized on the substrate. That is, according to the present invention, it is confirmed that the ultrafine particles are randomly dispersed in the matrix to almost the limit density.
[0014]
【The invention's effect】
As described above, in the present invention, a plurality of evaporation zones and vapor deposition zones are provided in the same vacuum chamber, and a plurality of vapors generated in the evaporation zone are guided to the substrate surface via the cylindrical guide portion. Since a plurality of vapors flow through the cylindrical guide portion at the stage where they flow, they are supplied to the substrate surface as a gas flow having a homogeneous composition. Therefore, a vapor deposition film in which ultrafine particles are uniformly dispersed is deposited on the substrate, and an ultrafine particle dispersed film having excellent quality stability can be obtained.
[Brief description of the drawings]
FIG. 1 shows a conventional vacuum deposition apparatus in which a vacuum chamber is divided into an evaporation chamber and a deposition chamber. FIG. 2 shows a vacuum deposition apparatus in which an evaporation zone and a vacuum zone are arranged in the same atmosphere according to the present invention. Electron micrograph of Fe ultrafine particle dispersion film obtained in Fig. 4 [Figure 4] Graph showing the effect of the amount of Fe fine particle dispersion on the magnetization curve of the ultrafine particle dispersion film
10: Vacuum chamber 11: Cylindrical guide part 20: Sputter source for ultrafine particles 30: Sputter source for matrix 21, 31: Target 22: Gas cylinder 23, 33: Flow control valve 24, 34: Power supply 41: For high vacuum Oil diffusion pump 42: Oil rotary pump for low vacuum S: Substrate

Claims (2)

A plurality of types of vapor are generated from a plurality of sputter sources arranged in the same vacuum chamber, and the single or plural first vapors are condensed into ultrafine particles in the process of guiding them to the surface of the substrate through the cylindrical guide part, Vaporized and mixed with other vapors sent through the cylindrical guide, and the ultrafine particles and other vapors that have been mixed by diffusion are deposited on the surface of the substrate, and the ultrafine particles are uniformly dispersed in the matrix generated from the other vapors. A method for producing an ultrafine particle dispersion film, comprising forming a film on a substrate surface. A plurality of sputtering sources that are arranged in one vacuum chamber and whose input power is controlled independently, and vapor generated in the first sputtering source is condensed into ultrafine particles and led to a substrate arranged in the same vacuum chamber. A cylindrical guide that guides other vapor generated by other sputtering sources to the substrate disposed in the same vacuum chamber, and the ultrafine particles and other vapors diffuse to each other when passing through the cylindrical guide. An apparatus for producing an ultrafine particle dispersion film, characterized by mixing.

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