RF sputtering device for controlling atomic layers of thin films

Abstract

The present invention relates to a radio frequency (RF) sputtering device for controlling the atomic layer of a thin film, and more specifically to the following RF sputtering device, that is, when a metal film is prepared by the RF sputtering device, electric noise can be eliminated by forming a power cable and a power line from a single crystal copper wire, and physical vibrations can be blocked by supporting the RF sputtering body and a rotary pump with a vibration isolation part, thereby controlling particles falling off from a target material in units of atomic layers, so that the metal film grows in an epitaxial manner.

Description

Technical Field

[0001] The present invention relates to a radio frequency (RF) sputtering device for controlling the atomic layer of a thin film, and more specifically to the following RF sputtering device, that is, when a metal film is prepared by the RF sputtering device, electric noise can be eliminated by forming a power cable and a power line from a single crystal copper wire, and physical vibrations can be blocked by supporting the RF sputtering body and a rotary pump with a vibration isolation part, thereby controlling particles falling off from a target material in units of atomic layers, so that the metal film grows in an epitaxial manner. Background Art

[0002] The methods of forming thin films on substrates can be divided into chemical methods that synthesize solid materials of thin films through chemical reactions of gaseous raw materials and physical methods that use physical methods to evaporate the particles to be evaporated onto the substrate. Chemical methods include chemical vapor deposition and plating, and physical methods include sputtering and spin coating.

[0003] In sputtering, high-frequency (RF, Radio Frequency) power is applied to a target material as a deposition material under a vacuum state to cause the target material to fall off in the form of particles, which are then deposited onto the surface of an opposite substrate, thereby preparing a metal film.

[0004] This RF sputtering evaporation method is more economical than other thin film evaporation technologies and is therefore widely used in a variety of applications. However, the target particles do not fall off evenly from the entire surface, and electrical noise or physical vibrations are applied during the process of evaporating particles from the target to the substrate, which limits its use in preparing high-quality thin films.

[0005] In order to prepare high-quality metal films made of single crystals grown by epitaxial growth and having a specified directionality by using a radio frequency sputtering device, or to prepare metal films with surface roughness controlled at the nanometer (nm) level, it is necessary to eliminate electrical noise and physical vibrations so that the particles can be uniformly evaporated onto the substrate. Summary of the invention

[0006] Technical issues

[0007] The object of the present invention is to provide a radio frequency sputtering device that can eliminate electrical noise during the process of applying radio frequency power to a target material by forming a power cable and a network from single crystal copper wire, thereby preparing a high-quality metal film.

[0008] An object of the present invention is to provide a radio frequency sputtering apparatus that can use a single crystal metal as a target metal to separate homogeneous particles from the target by sputtering, thereby producing a high-quality metal thin film.

[0009] The object of the present invention is to provide a radio frequency sputtering device in which a sputtering body is separated from a low vacuum pump and both are supported by a vibration isolation part to eliminate physical vibrations of a chamber in which sputtering is performed, thereby enabling the preparation of high-quality metal films.

[0010] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and ordinary technicians in the technical field to which the present invention belongs can clearly understand other technical problems not mentioned through the description of the present invention.

[0011] Technical Solution

[0012] In order to solve the above problems and achieve the purpose, the present invention provides a radio frequency sputtering device for controlling the atomic layer of a thin film, which can eliminate electrical noise and physical vibration during the sputtering process to prepare a high-quality metal film.

[0013] Hereinafter, this manual will be described in more detail.

[0014] The present invention provides a radio frequency sputtering device for controlling the atomic layer of a thin film, comprising a sputtering body, provided with a substrate, a target material, and a chamber, wherein the target material is opposite to the substrate, and the chamber is used for performing a sputtering process to evaporate the target material onto the substrate; a power supply unit, connected to the target material of the sputtering body through a network to apply radio frequency power; a low vacuum pump unit, forming a vacuum inside the chamber of the sputtering body; and a gas supply unit, supplying reaction gas to the inside of the chamber, and a power cable for supplying power to the power supply unit is made of single crystal copper wire.

[0015] In the present invention, the target material of the sputtering body can be formed as a single crystal target material by cutting a cylindrical single crystal metal grown by the Czochralski method or the Brichmann method.

[0016] In the present invention, the network for transmitting the radio frequency power of the power supply unit to the sputtering body may be made of a single crystal copper wire.

[0017] In the present invention, the outdoor grounding portion grounded to the power supply portion may be made of a single crystal copper block obtained by cutting a cylindrical single crystal copper grown by the Czochralski method or the Brichmann method.

[0018] In the present invention, the corners of the bottom surface of the sputtering body can be supported by a vibration isolation part to prevent vibration from being transmitted from the ground. The vibration isolation part includes: a pointed object attached to the bottom surface of the sputtering body to support the sputtering body, in a pointed shape that gradually becomes sharper toward the ground; and a supporting block placed on the ground, with an insertion groove formed on the upper surface for accommodating the tip of the pointed object, thereby only fixing the planar position of the pointed object.

[0019] In the present invention, the low vacuum pump part is physically separated from the sputtering body and connected to the chamber via a connecting hose made of rubber material, and the center of the connecting hose is fixed on a wall surface connected to the ground.

[0020] In the present invention, the corners of the bottom surface of the low vacuum pump part can be supported by a vibration isolation part to prevent vibration from being transmitted from the ground. The vibration isolation part includes: a pointed object attached to the bottom surface of the low vacuum pump part to support the low vacuum pump part, and has a pointed shape that gradually becomes sharper toward the ground; and a supporting block placed on the ground, with an insertion groove formed on the upper surface for accommodating the tip of the pointed object, thereby only fixing the plane position of the pointed object.

[0021] Effects of the Invention

[0022] According to the RF sputtering device for controlling the atomic layer of a thin film of the present invention, power cables and networks are formed of single crystal copper wires to increase the stability of the power supplied to the sputtering device, eliminate the noise of the power supply, and eliminate electrical noise in the process of applying RF power to the target material by increasing the homogeneity of the plasma.

[0023] According to the radio frequency sputtering apparatus for controlling the atomic layer of a thin film of the present invention, a single crystal metal is used as a target material to allow particles separated from the target to be uniformly evaporated onto the entire surface of a substrate.

[0024] According to the RF sputtering device for controlling the atomic layer of a thin film of the present invention, the sputtering body is separated from the low vacuum pump part and both are supported by the vibration isolation part, thereby eliminating the physical vibration of the chamber of the body performing sputtering.

[0025] As described above, the target particles can be homogeneously separated and electrical noise and physical vibrations can be eliminated, thereby controlling the crystal structure of the metal film evaporated onto the substrate in units of atomic layers, thereby making it possible to make a high-quality metal film from a single crystal grown by epitaxial growth and having a specified directionality.

[0026] The effects of the present invention are not limited to the effects mentioned above, and those skilled in the art to which the present invention belongs can clearly understand other effects not mentioned through the detailed description and the description in the scope of protection claimed for the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a simplified diagram showing the structures of the radio frequency sputtering device for controlling the atomic layer of a thin film according to the present invention.

[0028] Figure 2 The graph is a result for comparing the quality of a thin film prepared by the radio frequency sputtering apparatus for controlling the atomic layer of a thin film according to the present invention and a thin film prepared by a conventional sputtering method.

[0029] Figure 3 The table shows the change in quality of the thin film associated with the case where each structure is gradually added to the radio frequency sputtering apparatus for controlling the atomic layer of the thin film according to the present invention. DETAILED DESCRIPTION

[0030] For the terms used in this specification, while considering the functions in the present invention, the currently widely used common terms are selected as much as possible, but these may be different according to the intention of the technicians in the field to which the present invention belongs, precedents or the emergence of new technologies. In addition, in certain cases, there are terms randomly selected by the applicant. In this case, their meanings will be recorded in detail in the description of the corresponding invention. Therefore, the terms used in the present invention should be defined according to the meaning of the terms and the overall content of the present invention, rather than relying solely on the simple term names.

[0031] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. Terms defined in commonly used dictionaries have the same meaning as in the context of the relevant technology and shall not be interpreted as ideal or overly formal meanings unless explicitly defined in this application.

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the described embodiments of the present invention may be transformed into various other forms, and the protection scope of the present invention is not limited to the embodiments described below. The shapes and sizes of the elements shown in the accompanying drawings may be exaggerated for a clearer description. Moreover, throughout the specification, the invention name of the present invention may be referred to as "RF sputtering device" or "sputtering device".

[0033] Figure 1 The present invention relates to a radio frequency sputtering device that can control the crystal structure of a metal film in units of atomic layers, thereby being able to prepare a high-quality metal film, such as Figure 1 As shown, the present invention includes a sputtering body 10 , a power supply unit 20 , a low vacuum pump unit 30 and a gas supply unit 40 .

[0034] The sputtering body 10 is a space for performing the sputtering process of evaporating a metal thin film onto a substrate 11, and includes a substrate 11, a target 12, and a chamber 13. The substrate 11 is used as the anode part of the sputtering process, and is usually in the shape of a sapphire disk. A target 12 is provided at the cathode part facing the substrate 11, and the target 12 is made of a metal substance that needs to be evaporated onto the thin film on the substrate 11. Such substrate 11 and target 12 are located inside the chamber 13, and the particles falling off from the target 12 are separated through a subsequent sputtering process and evaporated onto the substrate 11, thereby preparing a metal thin film.

[0035] The power supply unit 20 is a structure for applying radio frequency power as high frequency power to the target 12 of the sputtering body 10 in order to perform a sputtering process, and is connected to the target 12 via a network 22 .

[0036] On the other hand, in order to perform the sputtering process, the chamber 13 must be in a vacuum state, and the roughing pump 30 is a structure that sucks the fluid inside the chamber 13 to form a vacuum inside the chamber 13 of the sputtering body 10, and it can be a commonly used rotary pump. In addition, the gas supply unit 40 that supplies the reaction gas to the inside of the chamber 13 in a vacuum state in order to perform the sputtering process is connected to the chamber 13 of the sputtering body 10. The reaction gas supplied by the gas supply unit 40 can be argon (Ar) gas, and the higher the purity of the argon gas, the more uniformly the vapor deposition particles on the entire surface of the target material 12 are separated from the target material 12.

[0037] According to the structure described above, if radio frequency power is applied to the target material 12 in the chamber 13 supplied with reaction gas through the power supply unit 20 under vacuum state, the reaction gas is ionized by glow discharge, so that plasma discharge occurs between the substrate 11 and the target material 12, and the cations existing in the discharge area hit the surface of the target material 12 by the electricity, and the evaporated particles falling off the surface of the target material 12 are evaporated onto the substrate 11 facing it, thereby preparing a metal thin film.

[0038] On the other hand, in the present invention, the power cable 21 for supplying power to the power supply unit 20 is made of a single crystal copper wire, and the signal transmitted to the power cable 21 is not mixed with noise and signal distortion, and the stability of the radio frequency power applied to the target 12 is increased, so that the vapor-deposited particles can be uniformly dropped from the entire surface of the target 12, thereby improving the quality of the metal film vapor-deposited on the substrate 11. In particular, the single crystal copper wire constituting the power cable 21 and the single crystal terminal can only be connected physically. In this case, compared with joining the two parts by soldering, etc., the signal distortion caused by the tin-lead alloy is eliminated, and since the radio frequency power applied to the target 12 eliminates electrical noise, the vapor-deposited particles can be uniformly dropped from the entire surface of the target 12. On the other hand, the single crystal copper wire constituting the power cable 21 of the present invention can be processed into a wire material by punching a single crystal copper grown by the Czochralski method or the Brichmann method using a die having a wire cut or a wire pattern, or can be made into a wire material by drawing a single crystal copper.

[0039] Moreover, the homogeneity of the vapor-deposited particles falling off from the target material 12 is related to the crystallinity of the target material 12, because the vapor-deposited particles are separated from the target material 12. Therefore, in the present invention, the target material 12 included in the sputtering body 10 can be made of a single crystal metal, and in particular, in the method for preparing a single crystal metal, it can be made by cutting a cylindrical single crystal metal that is welded by a Czochralski method or a Brichmann method, and the cut single crystal metal can be in a disc shape or a quadrilateral. As described above, in the case where the target material 12 is made of a single crystal metal, metal particles are uniformly formed on the entire surface of the target material 12 in a prescribed direction, thereby separating homogeneous vapor-deposited particles, and thus a high-quality vapor-deposited metal film can be prepared. The type of single crystal metal forming the target material 12 depends on the type of metal film that needs to be vapor-deposited onto the substrate 11, and can be copper, silver, or a single element metal.

[0040] Furthermore, the network 22 for transmitting the RF power of the power supply unit 20 to the target 12 of the sputtering body 10 may also be made of single crystal copper wire. Since the network 22 for transmitting the RF power is also made of single crystal copper wire, the RF power applied to the target 12 can eliminate electrical noise and increase the stability of the power, so the homogeneity of the plasma discharge formed between the substrate 11 and the target 12 can be increased, so that the vapor deposition particles can be uniformly detached from the entire surface of the target 12.

[0041] In addition, the outdoor grounding portion 23 formed for grounding the power supply portion 20 is made of a single crystal copper block cut from a cylindrical single crystal copper grown by the Czochralski method or the Brichmann method, and the single crystal copper block as an example may be in the shape of a disk. When the metal type of the target material 12 is copper, the single crystal copper forming the outdoor grounding portion 23 may be prepared together with the target material 12. As described above, when the outdoor grounding portion 23 is made of a single crystal copper block, the stability of the radio frequency power can be increased, thereby allowing the vapor deposition particles to fall off uniformly.

[0042] As described above, by making the target material 12 homogeneous or eliminating electrical noise, the evaporated particles can be uniformly detached to improve the quality of the metal film. In addition, the present invention can also prevent physical vibration from being applied during the process of evaporating the evaporated particles detached from the target material 12 onto the substrate 11, so that the metal film can grow in a prescribed direction in an epitaxial manner, which will be explained below.

[0043] The corners of the bottom surface of the sputtering body 10 of the present invention described above can be supported by the vibration isolation part 50 to prevent the transmission of vibration from the ground. The vibration isolation part 50 does not transmit the vibration of the ground to the sputtering body 10. On the contrary, it has a mechanical irreversible structure that discharges the vibration occurring in the sputtering body 10 to the outside (ground) to offset it. Specifically, the vibration isolation part 50 includes a spike 51 and a support block 52. The spike 51 is a structure attached to the bottom surface of the sputtering body 10 and supports the sputtering body 10, and has a pointed shape that gradually becomes sharper toward the ground. The support block 52 is placed on the ground so as to accommodate the spike 51 on the upper surface. An insertion groove 52a for accommodating the tip of the spike 51 is formed on the upper surface of the support block 52. The plane position of the spike 51 is fixed by accommodating the spike 51 in the insertion groove 52a of the support block 52. As described above, the vibration generated from the ground only shakes the support block 52 through the vibration isolation part 50 composed of the spike 51 and the support block 52 without applying force to the spike 51, so that it will not be transmitted to the sputtering body 10 supported by the spike 51. As a result, the sputtering body 10 is not affected by the vibration of the ground, and no physical external force is transmitted in the process of evaporating the evaporation particles separated from the target 12 onto the substrate 11, and the evaporation is uniformly deposited on the substrate 11, thereby improving the quality of the metal film. On the other hand, the spike 51 only needs to be in a sharp angle shape, and it can be in various shapes such as a rounded sharp angle, a triangular sharp angle, and a square sharp angle.

[0044] Moreover, in order to further block the physical vibration of the sputtering body 10, the present invention can physically separate the sputtering body 10 from the low vacuum pump unit 30. In the process of sucking fluid in order to form a vacuum in the chamber 13 of the sputtering body 10, the rotary pump as an example of the low vacuum pump unit 30 generates a large vibration through the operation of the pump. If the sputtering body 10 and the low vacuum pump unit 30 are physically integrated, the vibration generated during the operation of the low vacuum pump unit 30 will be directly transmitted to the sputtering body 10, so that the vaporized particles evaporated on the substrate 11 are not uniform. Therefore, in the present invention, the low vacuum pump unit 30 is physically separated from the sputtering body 10 and connected to the chamber 13 through a connecting hose 31 made of rubber material. In order to block the vibration of the connecting hose 31 from being transmitted to the sputtering body 10, the center of the connecting hose 31 can be fixed to the wall connected to the ground.

[0045] On the other hand, when the low vacuum pump unit 30 is physically separated from the sputtering body 10, the low vacuum pump unit 30 itself also needs to block vibration, just as the vibration of the ground cannot be transmitted to the sputtering body 10. The corners of the bottom surface of the low vacuum pump unit 30 can be supported by the vibration isolation unit 50 to prevent the vibration from being transmitted from the ground, and the specific structure of the vibration isolation unit 50 is as described above.

[0046] Figure 2 The graph is a result for comparing the quality of a thin film prepared by the radio frequency sputtering apparatus for controlling the atomic layer of a thin film according to the present invention and a thin film prepared by a conventional sputtering method. Figure 3 The table is a table showing the change in the quality of the thin film associated with the gradual addition of each structure in the radio frequency sputtering apparatus for controlling the atomic layer of the thin film of the present invention. Figure 2 and Figure 3 , illustrating the quality of the film prepared by the present invention, thereby illustrating the advantages of the present invention.

[0047] Reference Figure 2 It can be seen that part I represents the situation of preparing a thin film by a common radio frequency sputtering method, in which the quality varies due to the growth of crystals in multiple directions, and part II represents the situation of eliminating electrical noise and physical vibrations by the present invention, in which there are almost no grain boundaries between crystals, and the surface is flat to the atomic level due to the growth in only one direction.

[0048] Reference Figure 3, the quality of the film is improved according to the gradually added structure, which will be further explained. First, when the film is prepared by the existing radio frequency sputtering device (1), the root mean square (RMS) value of the surface roughness reaches the level of ~45nm, but when the target material is replaced with a single crystal metal (2), it can be seen that its root mean square roughness is reduced to the level of ~10nm. In addition, when the outdoor grounding part is replaced with a single crystal copper block, when the power cable and the network are made of single crystal copper wire (3), the root mean square roughness is improved to the level of 0.2nm~0.5nm with a probability of 85%. Moreover, if the sputtering body is supported by a vibration isolation part (4), the root mean square roughness can reach the level of 0.2nm~0.4nm with a probability of 90%, and if the low vacuum pump part is physically separated from the sputtering body and the low vacuum pump part is supported by the vibration isolation part (5), the root mean square roughness can reach below 0.3nm with a probability of 98%.

[0049] As described above, those skilled in the art should understand that the present invention can be implemented in other specific embodiments without changing the technical concept or essential features of the present invention. Therefore, the above embodiments are illustrative embodiments in all aspects and should be understood as non-limiting embodiments.

[0050] Description of Reference Numerals

[0051] 10: Sputtering body

[0052] 11: Substrate

[0053] 12: Target

[0054] 13: Chamber

[0055] 20: Power Supply Department

[0056] 21: Power cable

[0057] 22: Internet

[0058] 23: Outdoor grounding

[0059] 30: Low vacuum pump

[0060] 31: Connecting hose

[0061] 40: Air supply department

[0062] 50: Vibration isolation part

[0063] 51: Spike

[0064] 52: Support block

[0065] 52a: Insertion slot

Claims

1. A radio frequency sputtering device for controlling the atomic layer of a thin film, characterized in that include: A sputtering body is provided with a substrate, a target material, and a chamber, wherein the target material faces the substrate, and the chamber is used for performing a sputtering process to evaporate the target material onto the substrate; A power supply unit connected to the target of the sputtering body through a network to apply radio frequency power; A low vacuum pump unit for forming a vacuum inside the chamber of the sputtering body; and A gas supply unit supplies reaction gas to the chamber. The corners of the bottom surface of the sputtering body and the low vacuum pump part are supported by a vibration isolation part to prevent vibration from being transmitted from the ground. The vibration isolation part comprises: A pointed object attached to each corner of the bottom surface of the sputtering body and the low vacuum pump part to support the sputtering body and the low vacuum pump part, and having a pointed shape gradually becoming sharper toward the ground; and The support block is placed on the ground and has an insertion groove formed on the upper surface for receiving the tip of the pointed object, so as to fix only the plane position of the pointed object. The low vacuum pump is physically separated from the sputtering body and connected to the chamber via a rubber hose. The center of the connecting hose is fixed to a wall surface connected to the ground to prevent vibration from being transmitted to the sputtering body. The sputtering body is not affected by ground vibration, and does not transmit any physical external force during the process of evaporating the evaporation particles separated from the target material onto the substrate, and can be uniformly evaporated on the substrate. The power cable for supplying power to the power supply part is made of single crystal copper wire, and the network for transmitting the radio frequency power of the power supply part to the sputtering body is made of single crystal copper wire, thereby increasing the stability of the radio frequency power applied to the target material and increasing the homogeneity of the plasma discharge formed between the substrate and the target material, so that the vapor-deposited particles are uniformly evaporated onto the substrate.

2. The radio frequency sputtering device for controlling the atomic layer of a thin film according to claim 1, characterized in that: The target material of the sputtering main body is formed into a single crystal target material by cutting a cylindrical single crystal metal grown by the Czochralski method or the Brichmann method.

3. The radio frequency sputtering device for controlling the atomic layer of a thin film according to claim 1, characterized in that: The outdoor grounding portion grounded to the power supply portion is made of a single crystal copper block obtained by cutting a cylindrical single crystal copper grown by the Czochralski method or the Brichmann method.

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