KR102430700B1 - Preparation method of ferromagnetic film and apparatus for ferromagnetic film - Google Patents

Abstract

The present invention relates to a manufacturing method of a ferromagnetic film and a manufacturing apparatus of a ferromagnetic film, wherein the manufacturing method comprises the following steps of: (a) preparing a sputter gun including a ferromagnetic target, and an insulating metal back plate and a conductive metal back plate that are sequentially provided on an surface facing a deposition surface of the ferromagnetic target; and (b) applying electric power to the sputter gun to deposit a material of the ferromagnetic target.

Description

A method for manufacturing a ferromagnetic film and an apparatus for manufacturing a ferromagnetic film

The present invention relates to a method for manufacturing a ferromagnetic film and an apparatus for manufacturing a ferromagnetic film.

As the semiconductor process progresses toward ultra-fine line width, a rapid increase in resistivity and problems of electron migration are emerging. As a solution to this, new materials that can replace copper (Cu) used in semiconductor processes are attracting attention. Among them, cobalt (Co) and nickel (Ni), which are ferromagnetic materials, have a shorter electron mean free path (EMFP) than copper (Cu) and have a high melting point, so fine line width and thermal stability Due to its excellent properties, it is attracting attention as a next-generation semiconductor material.

Most ferromagnetic thin film deposition uses atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes, but low deposition rates, high temperature atmosphere processes, and carbon contamination by precursors are problems. .

By using the magnetron deposition process, it is possible to solve the problems of atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes by depositing in a vacuum and room temperature atmosphere. However, the ferromagnetic target decreases the transmitted magnetic flux density due to the magnetization phenomenon, so that the magnetic field strength of the target surface is decreased. For this reason, there are problems in that plasma ignition is impossible and the applied power density is reduced during the magnetron deposition process. Furthermore, there are problems in that the process cost increases due to the low deposition rate due to the decrease in the applied power density, and the properties of the thin film such as decrease in crystal size and increase in resistivity are deteriorated.

Therefore, there is a need for research on a method for depositing a ferromagnetic thin film capable of solving such a problem.

"Correlation between pass-through flux of cobalt target and microstructure and magnetic properties of sputtered thin films", Xiu-Lan Xu et al., Rare Metals volume 40, 975-980 (2021)

An object of the present invention is to provide a method for manufacturing a ferromagnetic film and an apparatus for manufacturing a ferromagnetic film, which can solve the above problems.

An exemplary embodiment of the present invention, (a) preparing a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on the opposite surface of the deposition surface of the ferromagnetic target; and (b) applying power to the sputter gun to deposit a material of the ferromagnetic target.

Another embodiment of the present invention, a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on the opposite surface of the deposition surface of the ferromagnetic target; and a power supply device configured to apply a current to the sputter gun.

The method and apparatus for manufacturing a ferromagnetic film according to the present invention can solve a problem of a decrease in transmitted magnetic flux density due to a magnetization phenomenon in a magnetron deposition process of a ferromagnetic target. In addition, the method and apparatus for manufacturing a ferromagnetic film according to the present invention can dramatically increase the applied power density only by a simple method of providing an insulating metal backplate on the back side of the ferromagnetic target, and through this, a thin film having excellent properties can be deposited have.

1 is a schematic configuration diagram of a sputter gun according to an embodiment of the present invention.
2 is a schematic configuration diagram of an apparatus for manufacturing a ferromagnetic film according to an exemplary embodiment of the present invention.
3 is a graph showing the target temperature according to the magnetron deposition process time in the manufacturing method of the ferromagnetic film according to the embodiment.
4 is a graph showing the change in current according to the magnetron deposition process time in the manufacturing method of the ferromagnetic film according to the embodiment.
5 is a graph showing the resistivity of films deposited according to Examples and Comparative Examples.
6 is a diagram showing X-ray diffraction (XRD) of films deposited according to Examples and Comparative Examples.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In the present specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In the present specification, when a member is said to be located “on” another member, this includes not only a case in which a member is in contact with another member but also a case in which another member is present between the two members.

The present inventors have completed the present invention as a result of conducting research to solve various problems due to the impossibility of plasma ignition and reduction in applied power density during magnetron deposition using a ferromagnetic target. Specifically, the present invention increases the temperature of the ferromagnetic target to the Curie temperature within minutes without a separate heat source during magnetron deposition by adding a simple configuration including an insulating metal backplate between the ferromagnetic target and the conductive metal backplate. can go Furthermore, it is possible to generate a phase transition from the ferromagnetic target to a paramagnetic material and increase the transmitted magnetic flux density to dramatically increase the applied power density. It is possible to improve the problems of deterioration of the physical properties of the thin film, such as a decrease in size and an increase in specific resistance.

Furthermore, the method of manufacturing a ferromagnetic film according to an exemplary embodiment of the present invention includes atomic layer deposition (ALD) and chemical vapor deposition (CVD) processes in the semiconductor process field requiring ferromagnetic thin film deposition. Alternatively, it also has the advantage of solving the problem of low deposition rate, high temperature atmosphere process, and carbon contamination by precursors.

Hereinafter, the present invention will be described in detail.

An exemplary embodiment of the present invention, (a) preparing a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on the opposite surface of the deposition surface of the ferromagnetic target; and (b) applying power to the sputter gun to deposit a material of the ferromagnetic target.

According to an exemplary embodiment of the present invention, the ferromagnetic target may be a ferromagnetic metal having a Curie temperature or an alloy including the ferromagnetic metal. Specifically, the ferromagnetic target may be a single ferromagnetic metal having a Curie temperature or an alloy including one or more ferromagnetic metals regardless of size, thickness, purity, and type. The thickness of the ferromagnetic target may be adjusted according to the purpose. However, when the thickness of the ferromagnetic target is excessively thick, the decrease in the surface magnetic field strength due to the decrease in the transmitted magnetic flux density due to the magnetization may intensify and the applied power density may be lowered. It may be difficult to rise to the Curie temperature. In addition, when the thickness of the ferromagnetic target is too thin, deformation of the ferromagnetic target due to temperature is increased, and the process cannot be sustained for a long time.

According to an exemplary embodiment of the present invention, (a-1) providing a magnetic field applying means on the conductive metal backplate so that the magnetic field strength at the center of the surface of the ferromagnetic target is 1,500 Gauss or more and 10,000 Gauss or less. may include When the thickness of the ferromagnetic target increases, the surface magnetic field strength of the ferromagnetic target decreases, so that there are problems of inability to ignite plasma and low applied power density. A magnetic field application means such as a magnet of When the surface magnetic field strength of the ferromagnetic target is 10,000 Gauss or more, as the number of ions bound to the magnetic field increases, the deposition energy of the ions may decrease, thereby reducing the properties of the thin film. very difficult

According to an exemplary embodiment of the present invention, the heat insulating metal backplate may have a thermal conductivity of 100 W/(m·K) or less. When the thermal conductivity of the insulating metal backplate exceeds 100 W/(m·K), the thermal energy of the ferromagnetic target generated during the magnetron deposition process cannot be shielded, and the ferromagnetic target is heated to the Curie temperature. It cannot be raised, and it is difficult to achieve the object of the present invention.

1 is a schematic configuration diagram of a sputter gun according to an embodiment of the present invention. Specifically, in FIG. 1 , an insulating metal backplate 110 and a conductive metal backplate 120 are sequentially stacked on a ferromagnetic target 100 , and they are in contact with each other and are in an energized state. Furthermore, the insulating metal backplate 110 shields the thermal energy generated in the ferromagnetic target 100 during the magnetron deposition process, and raises the temperature of the ferromagnetic target 100 to the Curie temperature, the ferromagnetic target 100 causes a phase transition to the paramagnetic body. The conductive metal backplate 120 may be in direct contact with the magnet 200 to prevent local deterioration and demagnetization of the magnet. The clamp 300 is provided to prevent separation due to thermal expansion of the ferromagnetic target 100 during the magnetron deposition process and to fix the ferromagnetic target 100 and the stacked backplates 110 and 120 . Other configurations are general configurations used in the magnetron deposition apparatus, and detailed descriptions thereof will be omitted.

According to an exemplary embodiment of the present invention, the power density of the power applied in step (b) may be 3 W/cm 2 or more and 100 W/cm 2 or less. When the power density applied to the sputter gun is less than 3 W/cm 2 , the power density is too low to rise to the Curie temperature of the ferromagnetic target and/or to maintain the Curie temperature may be difficult. When power is applied at a power density of 100 W/cm 2 or more, there may be a problem in that the operation of the sputter gun becomes unstable due to a rapid increase in power density.

According to an exemplary embodiment of the present invention, step (b) may be to use a magnetron deposition method.

According to an exemplary embodiment of the present invention, the magnetron deposition system may use one or two or more process gases selected from the group consisting of argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe). have. Specifically, the process gas may be a gas injected into the vacuum chamber.

According to an exemplary embodiment of the present invention, step (b) may be performed under a pressure of 0.5 mTorr or more and 20 mTorr or less. When the step (b) is performed at a low pressure of less than 0.5 mTorr, plasma ignition may be difficult or it may be difficult to maintain plasma ignition due to the low gas density. In addition, when step (b) is performed at a pressure of more than 20 mTorr, due to collision of target atoms with gas molecules during deposition, deposition energy is reduced and scattered, and properties of the thin film are reduced.

Since the ferromagnetic film manufactured according to the manufacturing method is deposited as a thin film, it can be utilized in a semiconductor process requiring an ultra-fine line width. Specifically, the ferromagnetic film may refer to a ferromagnetic thin film deposited on a predetermined substrate.

In addition, another embodiment of the present invention, a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on the opposite surface of the deposition surface of the ferromagnetic target; and a power supply device configured to apply a current to the sputter gun.

2 is a schematic configuration diagram of an apparatus for manufacturing a ferromagnetic film according to an exemplary embodiment of the present invention. According to FIG. 2, the magnetron deposition equipment constituting the magnetron deposition system according to an embodiment of the present invention includes a vacuum chamber 1, a high vacuum pump 13 for making the vacuum chamber 1 into a vacuum state, and a low vacuum pump ( 14), a power supply supplying power to the process gas 10 and gas flow meter 11 for making a plasma source gas in the vacuum chamber 1, the deposition gun 3 for the magnetron deposition process, and the deposition gun 3 (2), an RF power supply 9 for supplying RF power to generate plasma to the RF antenna 5, and a matching network 8 for matching the RF power supply 9 to the RF antenna 5 , a sample 6 and a sample stand 7 are provided. Other configurations are general configurations used in the magnetron deposition apparatus, and detailed descriptions thereof will be omitted.

According to an exemplary embodiment of the present invention, the apparatus for manufacturing the ferromagnetic film may further include a magnetic field applying means on the conductive metal backplate. The magnetic field applying means may be a means for allowing the magnetic field strength at the center of the surface of the ferromagnetic target to be 1,500 Gauss or more and 10,000 Gauss or less, for example, a permanent magnet capable of maintaining the magnetic field strength of the ferromagnetic target surface within a target range. can be

Since the components described in the apparatus for manufacturing the ferromagnetic film are the same as those in the above-described method for manufacturing the ferromagnetic film, a description thereof will be omitted.

Hereinafter, examples will be given to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those of ordinary skill in the art.

[Example]

A titanium (Ti)/aluminum (Al)/vanadium (V) alloy with a weight ratio of 91:5.5:3 (diameter 3 inch, thickness 1 mm), and a conductive metal backplate made of copper (Cu) (3 inches diameter, 1 mm thickness, and purity 99.995 wt%) were sequentially laminated. At this time, the thermal conductivity of the heat insulating metal backplate was 6.7 W/(m·K).

The structure in which the ferromagnetic target, the insulating metal backplate and the conductive metal backplate are laminated was fixed to a sputter gun with a clamp as shown in FIG. 1 . At this time, the inner diameter of the clamp and the separation distance of the ferromagnetic target were 1 mm, which was similar to the size of the ferromagnetic target, so that it played a role of securely holding the ferromagnetic target without separation during thermal expansion of the ferromagnetic target during the deposition process. After clamping, the magnetic field strength at the center of the ferromagnetic target surface perpendicular to the magnet of the sputter gun was 2,200 Gauss.

After preparing an apparatus for manufacturing a ferromagnetic film as shown in FIG. 2, argon gas is injected into a vacuum chamber in a high vacuum state, a DC voltage of -500 V is applied under a process pressure of 2 mTorr, and a power density of 4 W/cm 2 is maintained. A magnetron deposition process was performed. After the magnetron deposition process, the temperature and power density of the ferromagnetic target were gradually increased, and the temperature of the ferromagnetic target reached about 1,100 °C within 40 seconds. In addition, a phase transition occurred in the ferromagnetic target from a ferromagnetic material to a paramagnetic material, the transmitted magnetic flux density increased, the plasma density increased, and the power density increased to 17 W/cm 2 at the same DC voltage.

3 is a graph showing the target temperature according to the magnetron deposition process time in the manufacturing method of the ferromagnetic film according to the embodiment. Specifically, FIG. 3 is a graph measured with an infrared thermometer having a wavelength of 2 μm to 2.6 μm, which can be measured from 450° C. to 2,000° C. through the window of the vacuum chamber during the magnetron deposition process. At this time, the emissivity was measured by fixing it to 0.23. After the start of the process, it rose rapidly to about 450 ℃ within 5 seconds, and then gradually increased to about 1,100 ℃, close to 1,121 ℃, which is the Curie temperature of cobalt (Co), and the temperature was maintained.

4 is a graph showing the change in current according to the magnetron deposition process time in the method of manufacturing the ferromagnetic film according to the embodiment. Specifically, it can be seen from FIG. 4 that a phase transition occurs in the ferromagnetic target from a ferromagnetic material to a paramagnetic material through a current that changes during the magnetron deposition process according to the embodiment. Specifically, it can be understood that the phase transition of the ferromagnetic target occurs in a section in which the current rapidly increases after about 25 seconds of the magnetron deposition process has elapsed.

[Comparative example]

Except for the insulating metal backplate, the magnetron deposition process was performed in the same manner as in Example 1.

5 is a graph showing the resistivity of thin films deposited according to Examples and Comparative Examples. Referring to FIG. 5 , it can be seen that the specific resistance of the thin film deposited according to the example to which the heat insulating metal backplate is applied is improved to be lower than that of the comparative example. In addition, it was confirmed that the difference in resistivity becomes more severe as the thickness of the manufactured thin film becomes thinner.

6 is a view showing X-ray diffraction (XRD) of thin films deposited according to Examples and Comparative Examples. Specifically, FIG. 6 is an X-ray diffraction (XRD) analysis using a sample deposited with a 35 nm thick thin film according to Examples and Comparative Examples. It was confirmed that a peak having more excellent crystallinity appeared.

1: vacuum chamber
2: power supply
3: sputter gun
4: Plasma
5: RF antenna
6: sample
7: sample stage
8: Matching Network
9: RF power supply
10: process gas
11: gas flow meter
12: vacuum gauge
13: high vacuum pump
14: low vacuum pump
100: ferromagnetic target
110: insulating metal back plate
120: conductive metal back plate
200: magnet
300: clamp
400: positive shield
500: cooling channel

Claims (8)

(a) preparing a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on opposite surfaces of the deposition surface of the ferromagnetic target; and
(b) applying power to the sputter gun to deposit the material of the ferromagnetic target;
The heat insulating metal backplate is a method of manufacturing a ferromagnetic film, characterized in that it has a thermal conductivity of 100 W / (m · K) or less. The method according to claim 1,
(a-1) further comprising the step of providing a magnetic field applying means on the conductive metal backplate so that the magnetic field strength at the center of the surface of the ferromagnetic target is 1,500 Gauss or more and 10,000 Gauss or less. The method according to claim 1,
The power density of the power applied in step (b) is 3 W/cm 2 or more and 100 W/cm 2 or less, the method of manufacturing a ferromagnetic film. The method according to claim 1,
The ferromagnetic target is a ferromagnetic metal having a Curie temperature or an alloy containing the ferromagnetic metal, a method of manufacturing a ferromagnetic film. delete The method according to claim 1,
The step (b) is a method of manufacturing a ferromagnetic film, characterized in that it is carried out under a pressure of 0.5 mTorr or more and 20 mTorr or less. a sputter gun comprising a ferromagnetic target, an insulating metal backplate and a conductive metal backplate sequentially provided on an opposite surface of the deposition surface of the ferromagnetic target; and
a power supply configured to apply a current to the sputter gun;
The heat insulating metal backplate is an apparatus for manufacturing a ferromagnetic film, characterized in that it has a thermal conductivity of 100 W/(m·K) or less. 8. The method of claim 7,
The apparatus for manufacturing a ferromagnetic film further comprising a magnetic field applying means on the conductive metal backplate.

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