Diamond thin film, coating device, and method for manufacturing diamond thin film

Abstract

To provide a diamond thin film capable of uniformly diffusing heat.SOLUTION: In a diamond thin film composed of diamond particles with an average particle size of 1000 nm or less, the thermal conductivity in the in-plane direction is 50% to 200% of the thermal conductivity in the direction perpendicular to the plane.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a diamond thin film produced by a plasma CVD method, a coating device including the diamond thin film, and a method for producing the diamond thin film. [Background technology]

[0002] Conventionally, as a countermeasure against heat generated in semiconductor devices, a diamond film with high thermal conductivity has been synthesized on the semiconductor device (for example, Patent Document 1). This Patent Document 1 describes that in order to reduce the thermal resistance at the interface between the semiconductor device and the diamond film, the diamond particles contained in the film are grown in a columnar shape upward from the device, and a diamond thin film is formed with large diamond particles as shown in Figure 5. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6516824 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a diamond thin film is formed using diamond crystals that are large relative to the film thickness, as in the case of Reference 1, there is a problem that a difference in thermal conductivity occurs between the perpendicular direction and the in-plane direction of the film, making it impossible to uniformly diffuse the heat generated in the components on the substrate.

[0005] The present invention has been made to solve the above problems, and its main object is to provide a diamond thin film that can diffuse heat uniformly. [Means for solving the problem]

[0006] That is, the diamond thin film according to the present invention is composed of diamond particles with an average particle size of 1000 nm or less, and has a thermal conductivity in the in-plane direction of 50% to 200% of the thermal conductivity in the direction perpendicular to the plane.

[0007] With this structure, the diamond thin film is made of small diamond particles, and the difference in thermal conductivity between the in-plane direction and the perpendicular direction of the film is small, so the heat transferred to the diamond thin film can be diffused evenly. As a result, when this thin film is formed on a semiconductor device, for example, the heat generated locally in a hot spot of the semiconductor device can be diffused evenly toward the surface of the device through this diamond thin film, achieving uniform heating of the entire semiconductor device.

[0008] The relative ratio of the average grain size of diamond contained in the film to the film thickness is preferably 1% or more and 30% or less. If the relative ratio is less than 1%, the thermal conductivity will be poor. Also, to prevent a difference in thermal conductivity between the perpendicular direction and the in-plane direction of the film, it is preferably 30% or less. Even more preferably, it is 10% or less. With this configuration, the diamond thin film is made up of diamond particles with a small particle size relative to the film thickness, so there is little difference in thermal conductivity between the perpendicular and in-plane directions of the film. Note that if the particle size relative to the film thickness is small, the thermal conductivity in the perpendicular direction will be smaller than that of conventional diamond thin films, but when forming a diamond thin film on a semiconductor device, the film thickness is much thinner than the spread of the film in the in-plane direction, so there is essentially no problem caused by the small thermal conductivity in the perpendicular direction.

[0009] In a specific embodiment of the present invention, the thermal conductivity of the film in the in-plane direction or the direction perpendicular to the plane is preferably 5 W / m·K or more.

[0010] In a specific embodiment of the present invention, the resistivity is 10 10 It is preferable that the resistance is Ωcm or more, as this ensures sufficient insulation and is advantageous when semiconductor devices coated with this thin film are stacked.

[0011] The nitrogen concentration in the film is preferably 10 ppm or more and 10,000 ppm or less. If the nitrogen concentration is less than 10 ppm, the surface is hydrogen-terminated, and when p-type conductivity is achieved, the n-type carriers decrease, resulting in a decrease in insulating properties. Therefore, a nitrogen concentration of 10 ppm or more is preferable. Even more preferably, a nitrogen concentration of 100 ppm or more is preferable. Furthermore, if the nitrogen concentration exceeds 10,000 ppm, the thermal conductivity decreases, so a nitrogen concentration of 10,000 ppm or less is preferable. Even more preferably, a nitrogen concentration of 5,000 ppm or less is preferable.

[0012] The hydrogen concentration in the film is preferably 500 ppm or more and 250,000 ppm or less. If the hydrogen concentration is less than 500 ppm, the diamond grain size will become large, resulting in a difference in thermal conductivity between the in-plane and perpendicular directions, so a concentration of 500 ppm or more is preferable. Even more preferably, it is 5000 ppm or more. Furthermore, if the hydrogen concentration exceeds 250,000 ppm, the amount of non-diamond components will increase, resulting in a decrease in thermal conductivity, so a concentration of 200,000 ppm or less is preferable. Even more preferably, it is 150,000 ppm or less.

[0013] The oxygen concentration in the film is preferably 10 ppm or more and 50,000 ppm or less. If the oxygen concentration is less than 10 ppm, the insulating properties of the diamond thin film of the present invention will decrease, so it is preferably 10 ppm or more. Even more preferably, it is 100 ppm or more. Furthermore, if the oxygen concentration exceeds 50,000 ppm, the amount of non-diamond components will increase and the thermal conductivity will decrease, so it is preferably 50,000 ppm or less. Even more preferably, it is 20,000 ppm or less.

[0014] The relative ratio of the nitrogen concentration in the film to the hydrogen concentration in the film is preferably 0.00004 or more and 20 or less. If the relative ratio is less than 0.00004, the hydrogen concentration is high and the diamond grain size is small, resulting in a decrease in thermal conductivity, so it is preferable that it be 0.001 or more. Even more preferably, it is 0.002 or more. Furthermore, if the relative ratio exceeds 20, the hydrogen concentration is low and the diamond grain size is large, resulting in a difference in thermal conductivity between the in-plane and perpendicular directions, so it is preferable that it be 20 or less. Even more preferably, it is 10 or less.

[0015] The coating device according to the present invention also includes a semiconductor device having a semiconductor substrate made of one or more materials selected from Si, SiC, Ge, SiGe, GaAs, GaN, GaAlN, InGaN, InP, InGaP, InGaAlP, Ga2O3, and ZnSe; The semiconductor device is provided with a diamond thin film that is composed of diamond particles with an average particle size of 1000 nm or less and has a thermal conductivity in the in-plane direction of 80% to 120% of the thermal conductivity in the direction perpendicular to the plane. Such a configuration provides the same effects as the diamond thin film described above.

[0016] A method for producing a diamond thin film according to the present invention includes supplying a source gas containing C, H, and O into a vacuum chamber in which a semiconductor device is placed; generating an inductively coupled plasma in the vacuum vessel by passing a high frequency current through an antenna disposed inside or outside the vacuum vessel; A method for producing a diamond thin film, in which the temperature of the semiconductor device is maintained in the range of 23°C (room temperature) to 400°C, and a diamond thin film is synthesized on the semiconductor substrate by a plasma CVD method using the generated inductively coupled plasma.

[0017] This configuration allows for the deposition of diamond thin films consisting of small diamond crystal grains at low temperatures, and also prevents damage to the semiconductor device by keeping the temperature below 400°C. [Effects of the Invention]

[0018] According to the present invention thus configured, it is possible to provide a diamond thin film that is made of polycrystalline diamond and is capable of uniformly diffusing heat. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a cross-sectional view of a semiconductor device including a diamond thin film according to the embodiment. [Figure 2] 1 is a schematic cross-sectional view of a diamond thin film according to one embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram of a film forming apparatus in the method for manufacturing a diamond thin film according to the embodiment. [Figure 4] FIG. 2 is a diagram showing the gas composition range of the source gas supplied in the diamond thin film manufacturing method according to the embodiment; [Figure 5] Schematic cross-sectional view of a conventional diamond thin film. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a diamond thin film F according to one embodiment of the present invention, a coating device C including said thin film, and a method for manufacturing them will be described with reference to the drawings. Note that in any of the drawings shown below, some details may be omitted or exaggerated as appropriate for ease of understanding. Identical components will be assigned the same reference numerals, and their explanations will be omitted as appropriate.

[0021] <Coating Device C> As shown in Figure 1, the coating device C comprises a diamond thin film F and a semiconductor device D covered with the thin film. The diamond thin film F provided on the device D is formed by a plasma CVD method using an inductively coupled plasma P.

[0022] Here, a plurality of coating devices C are stacked to be used as a stacked device. In this stacked state, each coating device C is connected via a solder bump. However, the coating devices C may also be used without being stacked.

[0023] The stacked devices are electrically connected to, for example, a package substrate, and are connected to a printed circuit board via the package substrate. In addition, a heat sink is attached to the stacked semiconductor devices to collectively dissipate heat generated by each substrate.

[0024] <Semiconductor Device D> The semiconductor device D serving as the substrate is, for example, a chip-like device measuring approximately 1 mm, 5 mm, or 10 mm. This semiconductor device has a semiconductor substrate (not shown) made of one or more materials selected from Si, SiC, Ge, SiGe, GaAs, GaN, GaAlN, InGaN, InP, InGaP, InGaAlP, Ga2O3, and ZnSe. Elements such as MOSFETs are formed on the surface of this semiconductor substrate. The semiconductor substrate here has through electrodes for connection to other semiconductor substrates.

[0025] The semiconductor device D of this embodiment has an insulating layer (not shown) made of an insulator such as SiO2, SiON, SiN, Al2O3, HfO, Ta2O5, or Y2O3 on a semiconductor substrate.

[0026] <Diamond Thin Film F> The diamond thin film F of this embodiment is composed of diamond particles having a small particle size relative to the film thickness, as shown in Figure 2. Here, "composed" means that the main component of the diamond thin film F is diamond particles, and the diamond thin film F may contain ultra-trace amounts of amorphous carbon, impurities, etc. Impurities include, for example, nitrogen, hydrogen, oxygen, etc. in diamond.

[0027] The average particle size of the diamond particles is preferably 1000 nm or less, more preferably 100 nm or less. From the viewpoint of manufacturing, this particle size is preferably 5 nm or more. Here, the average particle size is measured by cross-sectional observation with a transmission electron microscope (TEM) and the crystallite size obtained from the peak width in precession electron diffraction or X-ray diffraction.

[0028] The thickness of the diamond thin film F is preferably 1 μm or more and 10 μm or less. The thickness here is measured by observing the cross section with a scanning electron microscope (SEM).

[0029] The relative ratio of the average particle size of the diamond particles to the film thickness is preferably 1% or more and 30% or less, and more preferably 1% or more and 10% or less.

[0030] In the diamond thin film F of this embodiment, in order to ensure uniform heat diffusion within the film, the thermal conductivity in the in-plane direction of the film is between 50% and 200% of the thermal conductivity in the direction perpendicular to the film's plane. It is more preferable that it is between 80% and 125%. Furthermore, in order to ensure efficient heat dissipation from the semiconductor device D, the thermal conductivity in the in-plane direction or the direction perpendicular to the plane is preferably 5 W / m·K or higher. It is more preferable that it is 50 W / m·K or higher, even more preferably 200 W / m·K or higher, and even more preferably 500 W / m·K or higher.

[0031] The thermal conductivity here is measured by the laser flash method. Specifically, the thermal conductivity in the in-plane direction is measured by the lamellar method or the in-plane method.

[0032] The in-plane direction is a direction perpendicular to the thickness direction of the diamond thin film F, that is, any direction in the plane of the film or a plane parallel to the plane. In this case, it is also a direction along the surface of the coating device C (or semiconductor device D). The perpendicular direction is a direction parallel to the thickness direction of the diamond thin film F, that is, a direction perpendicular to the in-plane direction. In this case, it is a direction perpendicular to the surface of the coated device C (or semiconductor device D).

[0033] To ensure insulation between the coating devices when coating device C is stacked, the resistivity of the diamond thin film is set to 10 10 It is preferable that the resistivity is Ωcm or more.

[0034] The following describes the concentrations of impurities contained in the diamond thin film F. Here, nitrogen, hydrogen, and oxygen are contained as impurities.

[0035] The nitrogen concentration in the film is preferably 10 ppm or more and 10,000 ppm or less, and more preferably 100 ppm or more and 5,000 ppm or less.

[0036] The hydrogen concentration in the film is preferably 500 ppm or more and 250,000 ppm or less, and more preferably 5,000 ppm or more and 200,000 ppm or less.

[0037] The oxygen concentration in the film is preferably 10 ppm or more and 50,000 ppm or less, and more preferably 100 ppm or more and 20,000 ppm or less.

[0038] The relative ratio of the nitrogen concentration in the film to the hydrogen concentration in the film is preferably 0.00004 or more and 20 or less, and more preferably 0.001 or more and 10 or less.

[0039] <Diamond thin film F manufacturing equipment> Hereinafter, a film-forming apparatus 100 for producing the above-mentioned diamond thin film F will be described with reference to FIG.

[0040] 3, the film formation apparatus 100 includes a vacuum vessel 2 that is evacuated and into which a gas G is introduced, a gas supply mechanism 7 that supplies the gas G to the vacuum vessel 2, a linear antenna 3 disposed within the vacuum vessel 2, and a high-frequency power supply 4 that applies a high-frequency wave to the antenna 3 to generate an inductively coupled plasma P within the vacuum vessel 2. In this film formation apparatus 100, by applying a high-frequency wave from the high-frequency power supply 4 to the antenna 3, a high-frequency current IR flows through the antenna 3, an inductive electric field is generated within the vacuum vessel 2, and an inductively coupled plasma P is generated.

[0041] The vacuum vessel 2 is a vessel made of metal such as SUS or aluminum, and its interior is evacuated to a vacuum by a vacuum exhaust device 6. In this example, the vacuum vessel 2 is electrically grounded. The vacuum exhaust device 6 is equipped with a pressure regulator 61 such as a valve that adjusts the pressure inside the vacuum vessel 2. By controlling this pressure regulator 61, the pressure inside the vacuum vessel 2 during plasma generation can be adjusted, for example, to a pressure of 7 Pa or more and 100 Pa or less.

[0042] Gas G such as a source gas is introduced into the vacuum chamber 2 via a flow rate regulator (not shown) and a plurality of gas inlets 21 arranged in a direction along the antenna 3, for example.

[0043] A substrate holder 8 for holding a semiconductor device D is provided within the vacuum chamber 2, and a heater 81 for heating the semiconductor device D is provided within the substrate holder 8. The substrate holder 8 does not need to be electrically connected to the vacuum chamber 2. The film forming apparatus 100 of this embodiment may have a function of applying a bias voltage from a bias power supply 9 to the substrate holder 8, thereby adjusting the potential of the generated inductively coupled plasma within a range of, for example, +100 V to -100 V.

[0044] The gas supply mechanism 7 supplies gas G such as a source gas into the vacuum chamber 2 through the gas inlet 21. The gas supply mechanism 7 is configured to be able to supply a source gas containing at least C (carbon), H (hydrogen), and O (oxygen), and more specifically, is configured to be able to supply H gas, CH gas, and CO gas as the source gas.

[0045] The gas supply mechanism 7 is configured to supply H gas, CH gas, and CO gas at any flow rate. The gas supply mechanism 7 of this embodiment is configured to adjust the flow rate of each gas so that the ratio of the concentration of O atoms to the total concentration of O atoms and H atoms (O / (O+H)) in the source gas containing H gas, CH gas, and CO gas is, for example, 5 at % or more and 45 at % or less.

[0046] The gas supply mechanism 7 is also configured to supply a catalyst gas into the vacuum chamber 2 at a desired flow rate along with the raw material gas. This catalyst gas functions as a catalyst during plasma generation and promotes the decomposition of the raw material gas. Specifically, the gas supply mechanism 7 is configured to supply the catalyst gas so that the proportion of the catalyst gas to the total flow rate of all gases supplied into the vacuum chamber 2 (here, the total flow rate of the raw material gas and the catalyst gas) is, for example, 50% to 95%, preferably 70% to 90%. Specific examples of this catalyst gas include rare gases such as Ar gas, He gas, and Ne gas.

[0047] The antenna 3 is disposed above the semiconductor device D in the vacuum chamber 2, along the surface of the semiconductor device D. In this embodiment, a plurality of linear antennas 3 are disposed in parallel along the semiconductor device D (for example, substantially parallel to the surface of the semiconductor device D). The number of antennas 3 is not limited to a plurality, and may be just one.

[0048] The antenna 3 is a so-called LC antenna that includes an L portion that serves as an inductor and a C portion that serves as a capacitor. Specifically, the antenna 3 includes at least two tubular metal conductor elements 31 (hereinafter referred to as metal pipes 31), a tubular insulating element 32 (hereinafter referred to as insulating pipe 32) that is provided between adjacent metal pipes 31 and insulates the metal pipes 31, and a capacitor 33 that is a capacitive element that is provided between adjacent metal pipes 31 and electrically connected in series with them. The conductor elements 31 function as the L portion, and the capacitor 33 functions as the C portion.

[0049] As shown in Fig. 3, the antenna 3 has a power feed end 3a to which a high frequency is fed in the antenna direction (longitudinal direction X) and a grounded end 3b. A high frequency is applied to the power feed end 3a of each antenna 3 from a high frequency power supply 4 via a matching box 41. The frequency of the high frequency is 400 kHz or more and 100 MHz or less, for example, the common frequency of 13.56 MHz, but is not limited to this. For example, it may be 27.12 MHz, 40.68 MHz, 60 MHz, etc.

[0050] <Method of manufacturing diamond thin film F> Next, a method for manufacturing the diamond thin film F using the above-described film forming apparatus 100 will be described.

[0051] First, a semiconductor device D, which is a substrate, is set on a substrate holder 8 in a vacuum chamber 2 of a film forming apparatus 100, and the vacuum chamber 2 is evacuated by a vacuum exhaust device 6. Specifically, a plurality of semiconductor devices D are arranged in an area of, for example, 20 cm x 20 cm or 50 cm x 50 cm and then supplied to the film forming apparatus 100.

[0052] Before this film formation, the semiconductor device D may be subjected to a surface treatment such as a so-called scratching treatment or a seeding treatment. For example, the surface of the semiconductor device D may be subjected to a scratching treatment or a seeding treatment in which the surface is immersed in alcohol together with diamond fine particles and subjected to ultrasonic treatment to form irregularities on the surface.

[0053] Then, the semiconductor device D is heated by the heater 81. Here, the semiconductor device D is heated so that the temperature thereof is 23°C (room temperature) or higher and 400°C or lower. Specifically, the semiconductor device D is heated so that the temperature of the film formation surface, which is the surface of the semiconductor device D, falls within the above temperature range.

[0054] By setting the temperature at 400°C or less, it is possible to synthesize a diamond thin film F that contains diamond particles with a particle size of 1000 nm or less and has a thermal conductivity in the in-plane direction of 50% to 200% of the thermal conductivity in the direction perpendicular to the plane. Note that if the temperature of the semiconductor device D exceeds 400°C, the electrodes on the semiconductor substrate of the semiconductor device D may diffuse on the substrate surface, causing problems such as loss of insulation and slower operating speed.

[0055] (Supply of raw gas) Next, the gas supply mechanism 7 supplies H2 gas, CH4 gas, and CO2 gas as raw material gases into the vacuum chamber 2 at predetermined flow rates. In the method for producing the diamond thin film F of this embodiment, the flow rates of H2 gas, CH4 gas, and CO2 gas are adjusted so that the atomic ratios of O atoms, C atoms, and H atoms in the raw material gases fall within the shaded range shown in the composition ternary diagram (CHO diagram) of Figure 4. The atomic ratios of each atom are explained below.

[0056] (ratio of oxygen and hydrogen atoms) The flow rates of H gas, CH gas, and CO gas are controlled so that the ratio of the concentration of O atoms to the total concentration of O atoms and H atoms contained in the source gas to be supplied (O / (O+H)) is preferably 5 at % or more and 45 at % or less, more preferably 5 at % or more and 10 at % or less.

[0057] (ratio of oxygen to carbon atoms) The flow rates of H gas, CH gas, and CO gas are controlled so that the ratio of the concentration of C atoms to the total concentration of O atoms and C atoms (C / (O+C)) in the source gas to be supplied is preferably 45 at % or more and 70 at % or less.

[0058] (ratio of carbon to hydrogen atoms) Furthermore, the flow rates of H gas, CH gas, and CO gas are controlled so that the ratio of the concentration of H atoms to the total concentration of C atoms and H atoms (H / (C+H)) in the source gas to be supplied is preferably 60 at % or more and 95 at % or less, more preferably 90 at % or more and 95 at % or less.

[0059] (Catalyst gas supply) Furthermore, a catalyst gas such as Ar gas is supplied into the vacuum chamber 2 together with the source gas by the gas supply mechanism 7. The flow rate of the catalyst gas to be supplied is preferably set to 50% to 95% of the total flow rate of all gases supplied to the vacuum chamber 2, and more preferably 70% to 90%. By setting the flow rate of the catalyst gas to be supplied within this range, energy can be transferred from, for example, Ar, which is easily ionized, to CH4 during film formation, thereby generating a large amount of C2 radicals, which are likely to produce diamond. As a result, the ratio of the emission intensity of C2 radicals to the emission intensity of Hα radicals can be set to 30% to 300% in the emission spectrum of the inductively coupled plasma generated.

[0060] (Pressure inside the vacuum vessel) Then, while the raw material gas and catalyst gas are introduced by the gas supply mechanism 7, the pressure inside the vacuum chamber 2 is adjusted by the pressure regulator 61 to be 7 Pa or more and 100 Pa or less, more preferably 10 Pa or more and 50 Pa or less.

[0061] (Plasma generation and diamond thin film F deposition) Then, with the flow rates of the raw material gas and catalyst gas adjusted as described above and the pressure inside the vacuum chamber 2 adjusted, high frequency power is supplied from the high frequency power supply 4 to the antenna 3. This generates an inductive electric field inside the vacuum chamber 2, generating an inductively coupled plasma P, which forms a diamond thin film F on the semiconductor device D, thereby producing a coated device C. The frequency of the high frequency power is 13.56 MHz. The power density of the supplied high frequency power is 1.4 W / cm. 2The power density is 1000W / cm 2 Less than 100W / cm is preferable. 2 Less than 50W / cm is more preferable. 2 The following is even more preferred:

[0062] <Example> The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and modifications can be made within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present invention.

[0063] In the examples, samples of diamond thin films were deposited on semiconductor devices by changing the composition of the source gas, the pressure in the vacuum chamber 2, and the flow rate ratio of Ar gas by plasma CVD using the above-mentioned film deposition apparatus 100. The flow rate of the source gas, the composition of the source gas, the flow rate ratio of Ar gas, the pressure in the vacuum chamber 2, the frequency of the supplied high-frequency power, the power density of the supplied high-frequency power, and the substrate temperature during the production of the samples were as follows: Flow rate of H2 gas among raw gases: 0 sccm Flow rate of CH4 gas among raw gases: 10 sccm Flow rate of CO2 gas in raw gas: 5sccm Ratio of O atom concentration to the total concentration of O atoms and H atoms in the source gas (O / (O+H)): 20% Ar gas flow rate: 84% Pressure inside the vacuum chamber: 15Pa Frequency of supplied high frequency power: 13.56MHz Power density of supplied high frequency power: 1.4W / cm 2 Semiconductor substrate temperature: 100°C

[0064] Diamond thin film F was produced under the above conditions, and the grain size of the diamond contained in diamond thin film F was evaluated using a transmission electron microscope (TEM) and electron diffraction. As a result, the grain size of the diamond in diamond thin film F was found to be about 10 nm.

[0065] The thermal conductivity of the produced sample was evaluated using the laser flash method. The thermal conductivity in the in-plane direction of the film was 11 W / m K, and the thermal conductivity in the perpendicular direction of the film was 10 W / m K. Therefore, it was confirmed that diamond thin film F could be produced, with a small difference in thermal conductivity between the perpendicular and in-plane directions of the film, and capable of diffusing heat uniformly.

[0066] The nitrogen, hydrogen, and oxygen concentrations in the film were evaluated by secondary ion mass spectrometry (SIMS). The nitrogen concentration was approximately 7.0×10 19 atoms / cm 3 The hydrogen concentration is about 2.0×10 22 atoms / cm 3 The oxygen concentration is about 2.7 × 10 21 atoms / cm 3 Therefore, it was confirmed that the diamond thin film F contained impurities within the above-mentioned preferable range.

[0067] <Effects of this embodiment> According to this embodiment, the temperature of the semiconductor device D is maintained in the range of 23°C (room temperature) to 400°C, and the diamond thin film F is formed by plasma CVD using inductively coupled plasma P, which prevents the generation of large diamond particles and allows the synthesis of a diamond thin film F composed of diamond particles with an average particle size of 1000 nm or less, with thermal conductivity in the in-plane direction being 80% to 120% of the thermal conductivity in the perpendicular direction. This allows the heat generated in the semiconductor device D to be uniformly diffused via the diamond thin film F.

[0068] <Other embodiments> The film forming apparatus 100 of the present invention is not limited to the above embodiment.

[0069] For example, in the film formation apparatus 100 of the above embodiment, the antenna 3 that generates the inductively coupled plasma is disposed inside the vacuum chamber 2, but this is not limiting. In other embodiments, the film formation apparatus 100 may have a structure in which the antenna 3 is disposed outside the vacuum chamber 2.

[0070] It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, it will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects. [Explanation of symbols]

[0071] C···Coating Device D Semiconductor device F Diamond thin film 100 Plasma CVD equipment 2...Vacuum container 3 Antenna 7 Gas supply mechanism P...Plasma

Claims

1. It is composed of diamond particles with an average particle size of 1000 nm or less, A diamond thin film having a thermal conductivity in an in-plane direction of 50% to 200% of the thermal conductivity in a direction perpendicular to the plane.

2. 2. The diamond thin film according to claim 1, wherein the ratio of the average particle size of said diamond particles to the film thickness is 1% or more and 30% or less.

3. 2. The diamond thin film according to claim 1, wherein the thermal conductivity in the in-plane direction or the direction perpendicular to the plane is 5 W / m·K or more.

4. Resistivity is 10 １０ 2. The diamond thin film according to claim 1, wherein the resistivity is Ωcm or more.

5. 2. The diamond thin film according to claim 1, wherein the nitrogen concentration in the film is 10 ppm or more and 10,000 ppm or less.

6. 2. The diamond thin film according to claim 1, wherein the hydrogen concentration in the film is 500 ppm or more and 250,000 ppm or less.

7. 2. The diamond thin film according to claim 1, wherein the oxygen concentration in the film is 10 ppm or more and 50,000 ppm or less.

8. 2. The diamond thin film according to claim 1, wherein the relative ratio of the nitrogen concentration in the film to the hydrogen concentration in the film is 0.00004 or more and 20 or less.

9. Si, SiC, Ge, SiGe, GaAs, GaN, GaAlN, InGaN, InP, InGaP, InGaAlP, Ga ２ O ３ a semiconductor device having a semiconductor substrate made of one or more materials selected from the group consisting of ZnSe and ZnSe; A coating device comprising: a diamond thin film provided on the semiconductor device, the diamond thin film being composed of diamond particles with an average particle size of 1000 nm or less, and having a thermal conductivity in the in-plane direction of 80% to 120% of the thermal conductivity in the direction perpendicular to the plane.

10. supplying a source gas containing C, H, and O into a vacuum chamber in which a semiconductor device is placed; generating an inductively coupled plasma in the vacuum vessel by passing a high frequency current through an antenna disposed inside or outside the vacuum vessel; A method for producing a diamond thin film, which comprises maintaining the temperature of the semiconductor device in the range of 23°C to 400°C and synthesizing a diamond thin film on the semiconductor device by a plasma CVD method using the generated inductively coupled plasma.

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