Heat transfer sheet, semiconductor manufacturing apparatus, and method for manufacturing heat transfer sheet

Abstract

This heat transfer sheet is disposed between a first member and a second member and mediates heat exchange between the first member and the second member. The heat transfer sheet comprises a plurality of carbon nanotubes and a metal film. The plurality of carbon nanotubes are oriented along the thickness direction of the heat transfer sheet. The metal film is provided at the tip of each carbon nanotube.

Description

Heat transfer sheet, semiconductor manufacturing device, and method for manufacturing heat transfer sheet

[0001] Various aspects and embodiments of the present disclosure relate to a heat transfer sheet, a semiconductor manufacturing apparatus, and a method for manufacturing a heat transfer sheet.

[0002] For example, Patent Document 1 below discloses that "A modified CNT forest (modified carbon nanotube forest) comprises a CNT forest with CNTs oriented in a predetermined direction and microparticles supported on the CNTs, and is spun. The CNT forest can be produced by the manufacturing method (gas phase catalyst method) disclosed in Patent Document 1 or Non-Patent Document 1, or the manufacturing method (solid phase catalyst method) disclosed in Non-Patent Document 2. In these cases, the predetermined direction is along the normal direction of the CNT forest formation surface of the substrate used to form the CNT forest."

[0003] International Publication No. 2022 / 137950

[0004] The present disclosure provides a heat transfer sheet with high thermal conductivity.

[0005] One aspect of the present disclosure provides a heat transfer sheet disposed between a first member and a second member and mediating heat exchange between the first member and the second member, the heat transfer sheet including a plurality of carbon nanotubes and a metal film. The plurality of carbon nanotubes are oriented in a thickness direction of the heat transfer sheet. The metal film is provided at the tip of each of the carbon nanotubes.

[0006] According to various aspects and embodiments of the present disclosure, a heat transfer sheet with high thermal conductivity can be provided.

[0007] FIG. 1 is a diagram showing an example of the arrangement of a heat transfer sheet in an embodiment of the present disclosure. FIG. 2 is a schematic diagram showing an example of the structure of the heat transfer sheet. FIG. 3 is a schematic diagram showing an example of a contact portion between a first member and the heat transfer sheet. FIG. 4 is a diagram showing an example of a method for measuring the thermal resistance of the interface in the heat transfer sheet of a reference example. FIG. 5 is a diagram showing an example of the relationship between heat capacity and thermal resistance in the heat transfer sheet of a reference example. FIG. 6 is a diagram showing an example of a method for measuring the thermal resistance of the interface in the heat transfer sheet of this embodiment. FIG. 7 is a diagram showing an example of the relationship between heat capacity and thermal resistance in the heat transfer sheet of this embodiment. FIG. 8 is a diagram explaining an example of the heat transfer process in the heat transfer sheet of this embodiment. FIG. 9 is a diagram explaining an example of the heat transfer process in the heat transfer sheet of this embodiment. FIG. 10 is a flowchart showing an example of a method for manufacturing a heat transfer sheet. FIG. 11 is a diagram showing an example of the manufacturing process of the heat transfer sheet. FIG. 12 is a diagram showing an example of the manufacturing process of the heat transfer sheet. FIG. 13 is a diagram showing an example of the manufacturing process of the heat transfer sheet. Fig. 14 is a diagram showing the thermal resistance of a heat transfer sheet when heat treatment is not performed and the thermal resistance of a heat transfer sheet when heat treatment is performed. Fig. 15 is a diagram showing an example of a manufacturing process for a heat transfer sheet having CNTs and a metal film arranged on both sides. Fig. 16 is a diagram showing an example of a manufacturing process for a heat transfer sheet having CNTs and a metal film arranged on both sides. Fig. 17 is a diagram showing an example of a manufacturing process for a heat transfer sheet having CNTs and a metal film arranged on both sides. Fig. 18 is a diagram showing an example of a manufacturing process for a heat transfer sheet having CNTs and a metal film arranged on both sides. Fig. 19 is a diagram showing an example of a semiconductor manufacturing apparatus. Fig. 20 is a partially enlarged view showing an example of a semiconductor manufacturing apparatus.

[0008] The following describes in detail the embodiments of the disclosed heat transfer sheet, semiconductor manufacturing apparatus, and method for manufacturing the heat transfer sheet, with reference to the drawings. Note that the following embodiments do not limit the disclosed heat transfer sheet, semiconductor manufacturing apparatus, and method for manufacturing the heat transfer sheet.

[0009] When exchanging heat between two components, simply contacting the two components may result in low heat transfer efficiency depending on the condition of the contact surfaces. Therefore, sandwiching a sheet with high heat transfer performance between the two components may improve the heat transfer efficiency. Known examples of such heat transfer sheets include a heat transfer sheet containing multiple carbon nanotubes (CNT forests) oriented along the thickness direction. However, further improvements in heat transfer efficiency between the two components are needed.

[0010] The present disclosure can provide a heat transfer sheet with high thermal conductivity.

[0011] [Structure of heat transfer sheet 100] Figure 1 is a diagram showing an example of the arrangement of the heat transfer sheet 100 in one embodiment of the present disclosure. The heat transfer sheet 100 is arranged between a first member 200 and a second member 201. The first member 200 and the second member 201 are in contact with the heat transfer sheet 100. The heat transfer sheet 100 mediates heat exchange between the first member 200 and the second member 201. In this embodiment, the first member 200 and the second member 201 are conductive members such as metals.

[0012] 2 is a schematic diagram showing an example of the structure of the heat transfer sheet 100. The heat transfer sheet 100 includes a plurality of carbon nanotubes (CNTs) 102 and a plurality of metal films 103.

[0013] Each of the multiple CNTs 102 is arranged so as to be aligned along the thickness direction of the heat transfer sheet 100 (z direction in FIG. 2 ). A metal film 103 is formed at the tip of each CNT 102. In this embodiment, the metal film 103 is made of, for example, aluminum. As another example, the metal film 103 may be made of other metals including chromium, titanium, beryllium, etc.

[0014] The metal film 103 provided at the tip of each CNT 102 is preferably formed separately from the metal films 103 provided at the tips of the other CNTs 102. This allows the metal films 103 at the tips of each CNT 102 to be displaced independently as the CNT 102 bends. Specifically, as shown in FIG. 3 , for example, a metal film 103a is formed at the tip of a CNT 102a among the plurality of CNTs 102, and a metal film 103b is formed at the tip of a CNT 102b among the plurality of CNTs 102. The metal films 103a and 103b can be displaced independently as the CNTs 102a and 102b bend. The CNT 102a is an example of a first carbon nanotube, and the metal film 103a is an example of a first metal film. Moreover, the CNT 102b is an example of a second carbon nanotube, and the metal film 103b is an example of a second metal film.

[0015] 3, even if the surface of the first member 200 is uneven, more contact can be achieved between each CNT 102 and the second member 201 via the metal film 103. This improves the thermal conductivity between the first member 200 and the second member 201 via the heat transfer sheet 100.

[0016] 3, all of the metal films 103 formed on the tips of the CNTs 102 are separated from one another, but not all of the metal films 103 are necessarily separated from one another. That is, some of the multiple metal films 103 may be displaced integrally with other metal films 103. Even in such a case, the contact area between the second member 201 and the metal films 103 can be made larger than when all of the metal films 103 provided on the tips of the CNTs 102 are formed as an integral film.

[0017] 4 is a diagram showing an example of a method for measuring the thermal resistance of the interface of the heat transfer sheet 100' of the reference example. The heat transfer sheet 100' of the reference example has CNTs 102. However, in the heat transfer sheet 100' of the reference example, the metal film 103 is not provided at the tip of the CNTs 102.

[0018] 4, the heat source 300 is heated and then the heating of the heat source 300 is stopped. When the heating of the heat source 300 is stopped, the heat of the heat source 300 is transferred to the cooling source 301 via the heat transfer sheet 100', and the temperature of the heat source 300 drops. The thermal resistance and heat capacity can be determined by converting the transient response of the temperature change of the heat source 300 at this time into structure functions of the thermal resistance and heat capacity.

[0019] 5 is a diagram showing an example of the relationship between heat capacity and thermal resistance in the heat transfer sheet 100' of the reference example. Referring to FIG. 5, the total thermal resistance R is the thermal resistance at the interface between the heat source 300 and the heat transfer sheet 100', the thermal resistance inside the heat transfer sheet 100', and the thermal resistance at the interface between the heat transfer sheet 100' and the cooling source 301. th ' is approximately 4.51 cm 2 It was K / W.

[0020] Fig. 6 is a diagram showing an example of a method for measuring the thermal resistance of the interface in the heat transfer sheet 100 of this embodiment. The heat transfer sheet 100 of this embodiment has CNTs 102 and metal films 103. The metal films 103 provided at the tips of the CNTs 102 are in contact with a cooling source 301. In the example of Fig. 6, the metal films 103 formed at the tips of the CNTs 102 are shown simplified as a single film.

[0021] In the measurement method illustrated in FIG. 6, as in FIG. 4, the transient response of the temperature change of the heat source 300 is converted into a structural function of a parallel circuit of thermal resistance and thermal capacity to determine the thermal resistance and thermal capacity.

[0022] 7 is a diagram showing an example of the relationship between heat capacity and thermal resistance in the heat transfer sheet 100 of this embodiment. Referring to FIG. 7, the total thermal resistance R is the thermal resistance at the interface between the heat source 300 and the heat transfer sheet 100, the thermal resistance inside the heat transfer sheet 100, and the thermal resistance at the interface between the heat transfer sheet 100 and the cooling source 301. th is approximately 3.17 cm 2 It was K / W.

[0023] 5 and 7, the heat transfer sheet 100 of this embodiment can reduce thermal resistance compared to the heat transfer sheet 100' of the reference example in which the metal film 103 is not provided at the tips of the CNTs 102. The results of FIGS. 5 and 7 show that the thermal resistance at the interface between the heat source 300 and the heat transfer sheet and the thermal resistance inside the heat transfer sheet are the same, so it is thought that there is a difference in the thermal resistance at the interface between the heat transfer sheet and the cooling source 301. Therefore, in the heat transfer sheet 100 of this embodiment, by providing the metal film 103 at the tips of the CNTs 102, the thermal resistance at the interface between the heat transfer sheet 100 and the cooling source 301 can be reduced.

[0024] This can be explained, for example, as follows: In a material that does not have many free electrons, such as CNT 102, heat is transferred as lattice vibrations, as shown in Fig. 8. In the example of Fig. 8, lattice vibrations are conceptually shown by wavy lines.

[0025] The heat transferred as lattice vibrations within CNT 102 vibrates the atoms of cooling source 301 at the interface between CNT 102 and cooling source 301. When the atoms of cooling source 301 vibrate and their temperature rises, the temperature of free electrons also rises. The free electrons with increased temperature then diffuse within cooling source 301, transferring heat within cooling source 301.

[0026] However, in the heat transfer sheet 100' of the reference example, as shown in Fig. 8, only a portion of the tip of the CNT 102 is in contact with the cooling source 301. Therefore, at the interface between the CNT 102 and the cooling source 301, the lattice vibrations in the CNT 102 are not easily transmitted to the atoms of the cooling source 301. Therefore, in the heat transfer sheet 100' of the reference example, the thermal resistance at the interface between the CNT 102 and the cooling source 301 is high.

[0027] In contrast, in the heat transfer sheet 100 of this embodiment, as shown in Fig. 9, for example, heat transferred as lattice vibrations in the CNTs 102 first vibrates atoms in the metal film 103 formed at the tips of the CNTs 102. At this time, the CNTs 102 and the metal film 103 are in closer contact than in simple contact, and the contact surface between the CNTs 102 and the metal film 103 is large. Therefore, at the interface between the CNTs 102 and the metal film 103, the heat transferred as lattice vibrations in the CNTs 102 can efficiently vibrate atoms in the metal film 103.

[0028] When atoms in the metal film 103 vibrate and the temperature of the atoms rises, the temperature of the free electrons also rises. The heated free electrons then diffuse within the metal film 103, transferring heat. At the interface between the metal film 103 and the cooling source 301, electrons are responsible for transporting heat, allowing heat to be transferred more efficiently than heat transferred by lattice vibration. Therefore, even if the contact area between the metal film 103 and the cooling source 301 is small, heat can be transferred efficiently, and the thermal resistance at the interface between the metal film 103 and the cooling source 301 can be reduced.

[0029] The CNTs 102 contained in the heat transfer sheet 100 have low electrical resistance. Therefore, when the heat transfer sheet 100 is disposed between the first member 200 and the second member 201, it is possible to reduce the potential difference between the first member 200 and the second member 201.

[0030] [Method for Manufacturing Heat Transfer Sheet 100] FIG. 10 is a flowchart showing an example of a method for manufacturing the heat transfer sheet 100.

[0031] First, a sheet having a plurality of CNTs 102 formed on a substrate 101 is prepared (step S10). The substrate 101 is made of, for example, silicon. Step S10 is an example of process a). In step S10, a sheet having a plurality of CNTs 102 aligned along the thickness direction of the substrate 101 (the z direction in FIG. 10) is prepared, as shown in FIG. 11, for example.

[0032] Here, when multiple CNTs 102 are formed on the substrate 101, the lengths of the CNTs 102 may differ, for example, as shown in Fig. 11. Furthermore, the tips of the CNTs 102 may be curved, and the tip of one CNT 102 may overlap another CNT 102. Therefore, even if the metal film 103 is formed in this state, the metal film 103 may not be formed on the tips of some of the CNTs 102.

[0033] Next, the tips of the CNTs 102 are etched (step S11). Step S11 is an example of process d). In step S11, the tips of the multiple CNTs 102 are etched, for example, by plasma etching. The plasma etching conditions are, for example, as follows: Atmosphere: Argon gas Current: 10 mA Etching time: 60 seconds Apparatus used: SEDE-P manufactured by Meiwafosis Co., Ltd.

[0034] This reduces the difference in length between the CNTs 102, and allows the tips of the CNTs 102 to be exposed without being covered by other CNTs 102, as shown in FIG. 12, for example.

[0035] In this embodiment, the tips of the CNTs 102 are etched using plasma in step S11, but the disclosed technology is not limited to this. As another example, the tips of the CNTs 102 may be etched using heat or a chemical solution.

[0036] Furthermore, if the difference in length between the CNTs 102 is small and the tip of a CNT 102 does not cover another CNT 102, step S11 may be omitted.

[0037] Next, a metal film 103 is formed on the tips of the plurality of CNTs 102 (step S12). Step S12 is an example of process b). In this embodiment, in step S12, an aluminum metal film 103 is formed on the tips of each of the CNTs 102 by sputtering.

[0038] In step S12, the metal film 103 is formed on the substrate 101 on which no CNTs 102 are formed under the same conditions as those for forming the metal film 103 having a thickness in the range of 10 nm to 100 nm. This makes it possible to prevent the metal films 103 formed on the tips of all adjacent CNTs 102 from being integrated together.

[0039] In this embodiment, in step S12, the metal film 103 is formed by sputtering on the tip of each CNT 102, but the disclosed technology is not limited to this. As another example, the metal film 103 may be formed on the tip of each CNT 102 by other film formation methods such as chemical vapor deposition (CVD), electron beam evaporation, or pulsed laser deposition (PLD).

[0040] As a result, a heat transfer sheet 100 is formed on the substrate 101, as shown in Fig. 13. Note that the metal films 103 formed on the tips of the CNTs 102 do not all need to be separated from each other, as in the case of the metal film 103c in Fig. 13, for example.

[0041] Next, a heat treatment is performed (step S13). Step S13 is an example of process e). This improves the adhesion between the CNTs 102 and the metal film 103, and further reduces the thermal resistance of the heat transfer sheet 100. In step S13, the substrate 101 on which the heat transfer sheet 100 is formed is carried into a heat treatment device, and the heat treatment is performed under the following conditions, for example: Treatment temperature: 650°C Gas supplied into the heat treatment device: argon gas Pressure inside the heat treatment device: 12 kPa Treatment time: 30 minutes

[0042] Next, the heat transfer sheet 100 is peeled off from the substrate 101 (step S14). Step S14 is an example of process c). In step S14, the substrate 101 on which the heat transfer sheet 100 has been formed is carried into a heat treatment device. Then, argon gas is supplied into the heat treatment device at a flow rate of 800 sccm, and the pressure inside the heat treatment device is adjusted to 40 kPa. Then, after the temperature of the substrate 101 on which the heat transfer sheet 100 has been formed is heated to 490°C, air is supplied into the heat treatment device at a flow rate of 200 sccm while maintaining the pressure inside the heat treatment device.

[0043] Because there is an iron particle catalyst between the CNTs 102 and the substrate 101, the interface between the CNTs 102 and the iron particles reacts with oxygen due to the catalytic action of the iron, oxidizing and releasing as CO2. As a result, only the base portions of the CNTs 102 are cut, and the CNTs 102 are peeled off from the substrate 101. This peels off the heat transfer sheet 100 from the substrate 101. The heat transfer sheet 100 is then cooled and carried out from the heat treatment device. This makes it possible to produce a heat transfer sheet 100 having a plurality of CNTs 102 oriented along the thickness direction of the heat transfer sheet 100 (the z direction in FIG. 2), with a metal film 103 provided at the tip of each CNT 102, as shown in FIG. 2, for example.

[0044] Although the heat treatment in step S13 is not necessarily performed, performing the heat treatment in step S13 can further reduce the thermal resistance of the heat transfer sheet 100. Fig. 14 is a diagram showing the thermal resistance of the heat transfer sheet 100 when no heat treatment is performed and when heat treatment is performed.

[0045] The thermal resistance of the heat transfer sheet 100 when heat treatment is performed is lower than the thermal resistance of the heat transfer sheet 100 when heat treatment is not performed, as shown in Figure 14. This tendency is observed regardless of the thickness of the metal film 103 formed on the tip of the CNT 102.

[0046] Furthermore, in the above-described embodiment, the CNTs 102 and the metal film 103 are formed on one surface of the substrate 101, but the disclosed technology is not limited to this. As another example, the metal film 103 may also be formed on the surface of the heat transfer sheet 100 that was in contact with the substrate 101. That is, the metal film 103 may be formed on both ends of each CNT 102. Note that if the surface of the heat transfer sheet 100 is rough after being peeled off from the substrate 101, the surface may be etched using plasma or the like before the metal film 103 is formed.

[0047] Alternatively, a heat transfer sheet having CNTs 102 and metal films 103 disposed on both sides may be formed by the method illustrated in Figures 15 to 18. Figures 15 to 18 are diagrams showing an example of a manufacturing process for a heat transfer sheet having CNTs 102 and metal films 103 disposed on both sides.

[0048] First, two sheets (see FIG. 12 ) are prepared after the tips of the CNTs 102 have been etched. Then, as shown in FIG. 15 , for example, the two sheets are bonded together with an adhesive layer 203 interposed between them so that the surfaces of the CNTs 102 face each other. The adhesive layer 203 may be made of a resin material such as polyvinylidene chloride (PVDC). The adhesive layer 203 preferably has a thickness of, for example, 10 μm or less.

[0049] 16, for example, the two heat transfer sheets 100 are heated at about 210° C. for about 1 minute while applying a pressure of, for example, 1 to 3 MPa in the direction of the arrow. As a result, the two heat transfer sheets 100 are pressure-bonded together via the adhesive layer 203.

[0050] Next, the substrate 101 is peeled off, for example, as shown in FIG. 17. Then, as shown in FIG. 18, for example, a metal film 103 is formed on the surface of the CNTs 102. This makes it possible to form a heat transfer sheet 100" in which the CNTs 102 and the metal film 103 are arranged on both surfaces. In the heat transfer sheet 100" illustrated in FIG. 18, the metal film 103 is formed on both the tips of the CNTs 102 on one surface of the heat transfer sheet 100" and the tips of the CNTs 102 on the other surface of the heat transfer sheet 100". This makes it possible to further improve the thermal conductivity performance of the heat transfer sheet 100".

[0051] If the surfaces of the CNTs 102 are rough after the substrate 101 has been peeled off, the surfaces of the CNTs 102 may be etched using plasma or the like before the metal film 103 is formed.

[0052] [Application example of heat transfer sheet 100] The heat transfer sheet 100 described in the above embodiment can be used in, for example, a semiconductor manufacturing apparatus 1 shown in Fig. 19. Fig. 19 is a diagram showing an example of the semiconductor manufacturing apparatus 1. The semiconductor manufacturing apparatus 1 shown in Fig. 19 is a capacitively coupled plasma processing apparatus. The semiconductor manufacturing apparatus 1 includes a first chamber 10, a second chamber 20, and a substrate support 30.

[0053] The first chamber 10 provides an internal space. The first chamber 10 is made of a metal such as aluminum. The first chamber 10 is electrically grounded. A corrosion-resistant film may be formed on the surface of the first chamber 10.

[0054] The first chamber 10 includes a substantially cylindrical sidewall 10s. The central axis of the sidewall 10s extends vertically and is shown as axis AX in FIG. 19 . The sidewall 10s provides a passage 10p. The internal space of the first chamber 10 is connected to the internal space of a transfer chamber (not shown) via the passage 10p. The passage 10p can be opened and closed by a gate valve 10g. The substrate W passes through the passage 10p when being transferred between the internal space of the first chamber 10 and the outside of the first chamber 10.

[0055] The side wall 10s further provides an opening 10o. The opening 10o has a size that allows the second chamber 20 to pass through. The internal space of the first chamber 10 can be connected to the internal space of a transfer module (not shown) via the opening 10o. The opening 10o can be opened and closed by a gate valve 10v.

[0056] In the example of Figure 19, a portion of the side wall 10s has a double structure formed of an inner wall 10i and an outer wall 10e. The inner wall 10i and the outer wall 10e provide a space 10q therebetween. An opening 10o is formed in the inner wall 10i and the outer wall 10e. A gate valve 10v is provided along the inner wall 10i to open and close the opening 10o.

[0057] The first chamber 10 further includes an upper portion 10u. The upper portion 10u extends from the upper end of the side wall 10s in a direction intersecting with the axis line AX. The upper portion 10u provides an opening in a region intersecting with the axis line AX.

[0058] The first chamber 10 further includes a movable part 10m. The movable part 10m is provided below the upper part 10u of the first chamber 10 and inside the side wall 10s. The movable part 10m is configured to be movable upward and downward within the first chamber 10.

[0059] The semiconductor manufacturing apparatus 1 further includes a lift mechanism 12. The lift mechanism 12 is configured to move the movable part 10m upward and downward. The lift mechanism 12 includes a drive device 12d and a shaft 12s. The movable part 10m is fixed to the shaft 12s. The shaft 12s extends upward from the movable part 10m through an opening in the upper part 10u. The drive device 12d is provided outside the first chamber 10. The drive device 12d is configured to move the shaft 12s upward and downward. The drive device 12d includes, for example, a motor. The upward and downward movement of the shaft 12s causes the movable part 10m to move upward and downward.

[0060] The semiconductor manufacturing apparatus 1 further includes a bellows 14. The bellows 14 is provided between the movable part 10m and the upper part 10u. The bellows 14 separates the internal space of the first chamber 10 from the outside of the first chamber 10. The lower end of the bellows 14 is fixed to the movable part 10m. The upper end of the bellows 14 is fixed to the upper part 10u.

[0061] The movable part 10m includes a lower member 10a and an upper member 10b. The lower member 10a and the upper member 10b are fixed to each other. The lower member 10a is formed in a substantially disk shape from a conductor such as aluminum. The lower member 10a constitutes an upper electrode in the semiconductor manufacturing apparatus 1. The upper member 10b has a substantially cylindrical shape. The upper member 10b extends along the outer periphery of the lower member 10a and above the lower member 10a. The lower end of the above-mentioned bellows 14 is fixed to the upper end of the upper member 10b.

[0062] The movable part 10m constitutes a shower head together with a ceiling part (to be described later) of the second chamber 20. That is, the movable part 10m constitutes a part of the shower head that supplies gas to the processing space S (to be described later). The movable part 10m provides a gas diffusion chamber 10d and a plurality of gas holes 10h.

[0063] A gas diffusion chamber 10d is provided in the lower member 10a. A gas supply unit 16 is connected to the gas diffusion chamber 10d. The gas supply unit 16 is provided outside the first chamber 10. The gas supply unit 16 includes one or more gas sources used in the semiconductor manufacturing apparatus 1, one or more flow controllers, and one or more valves. Each of the one or more gas sources is connected to the gas diffusion chamber 10d via a corresponding flow controller and a corresponding valve. A plurality of gas holes 10h extend downward from the gas diffusion chamber 10d.

[0064] The substrate support 30 is disposed within the first chamber 10 and below the movable part 10m. The substrate support 30 supports a substrate W placed thereon. The substrate support 30 is supported by a support part 31. The support part 31 is formed in a substantially cylindrical shape from an insulator such as quartz. The support part 31 extends upward from a bottom plate 32. The bottom plate 32 may be formed from a metal such as aluminum.

[0065] The substrate support 30 includes a lower electrode 34 and an electrostatic chuck 36. The lower electrode 34 is formed in a substantially disk shape from a conductor such as aluminum. The central axis of the lower electrode 34 substantially coincides with the axis AX. The lower electrode 34 has a flow path 34f formed therein. The flow path 34f extends, for example, in a spiral shape. The flow path 34f is connected to a chiller unit 35. The chiller unit 35 is provided outside the first chamber 10 and supplies a coolant to the flow path 34f. The coolant supplied to the flow path 34f is returned to the chiller unit 35.

[0066] The semiconductor manufacturing apparatus 1 further includes a first high-frequency power supply 41 and a second high-frequency power supply 42. The first high-frequency power supply 41 generates a first high-frequency power. The first high-frequency power has a frequency of, for example, 27 MHz or higher, which is suitable for generating plasma. The first high-frequency power supply 41 is electrically connected to the lower electrode 34 via a matching device 41m. The matching device 41m has a matching circuit for matching the impedance of the load side (lower electrode 34 side) of the first high-frequency power supply 41 to the output impedance of the first high-frequency power supply 41. Note that the first high-frequency power supply 41 may be connected to the upper electrode 34, rather than the lower electrode 34, via the matching device 41m.

[0067] The second high frequency power supply 42 is a power supply that generates second high frequency power. The second high frequency power has a frequency of, for example, 13.56 MHz or less that is suitable for attracting ions to the substrate W. The second high frequency power supply 42 is electrically connected to the lower electrode 34 via a matching device 42m. The matching device 42m has a matching circuit that matches the impedance on the load side (lower electrode 18 side) of the second high frequency power supply 42 to the output impedance of the second high frequency power supply 42.

[0068] The electrostatic chuck 36 is disposed on the lower electrode 34. The electrostatic chuck 36 includes a main body and an electrode 36a, which is a film formed from a conductor. The main body of the electrostatic chuck 36 is formed in a substantially disc shape from ceramics or the like. The central axis of the electrostatic chuck 36 substantially coincides with the axis AX. The substrate W is placed on the upper surface of the main body of the electrostatic chuck 36. The electrode 36a is disposed within the main body of the electrostatic chuck 36. The electrode 36a is connected to a DC power supply 36d via a switch 36s. When a voltage from the DC power supply 36d is applied to the electrode 36a, an electrostatic attraction is generated between the electrostatic chuck 36 and the substrate W. The generated electrostatic attraction attracts the substrate W to the electrostatic chuck 36, whereby the substrate W is held by the electrostatic chuck 36. The semiconductor manufacturing apparatus 1 may be provided with a gas line for supplying a heat transfer gas (e.g., helium gas) to the gap between the electrostatic chuck 36 and the back surface of the substrate W.

[0069] The substrate support 30 supports an edge ring ER disposed thereon. The substrate W is placed on the electrostatic chuck 36 within a region surrounded by the edge ring ER. The edge ring ER is made of, for example, silicon, quartz, or silicon carbide.

[0070] The semiconductor manufacturing apparatus 1 further includes an insulating portion 37. The insulating portion 37 is made of an insulator such as quartz and has a generally cylindrical shape. The insulating portion 37 extends along the outer periphery of the lower electrode 34 and the outer periphery of the electrostatic chuck 36.

[0071] The semiconductor manufacturing apparatus 1 further includes a conductor 38. The conductor 38 is formed in a generally cylindrical shape from a conductor such as aluminum. The conductor 38 is provided along the outer periphery of the substrate support 30. Specifically, the conductor 38 extends circumferentially radially outside the insulating portion 37. The radial direction and the circumferential direction are both directions based on the axis AX. The conductor 38 is connected to ground. In one example, the conductor 38 is connected to ground via the bottom plate 32 and the first chamber 10.

[0072] The semiconductor manufacturing apparatus 1 further includes a cover ring 39. The cover ring 39 is formed in a ring shape from an insulator such as quartz. The cover ring 39 is provided on the insulating portion 37 and the conductor portion 38 so as to be located radially outside the region in which the edge ring ER is disposed.

[0073] The semiconductor manufacturing apparatus 1 further includes a contact 40. The contact 40 is electrically connected to the conductor portion 38. The second chamber 20 abuts against the contact 40 while defining a processing space S together with the substrate support 30. The processing space S is a space in which the substrate W is processed. In the semiconductor manufacturing apparatus 1 illustrated in FIG. 19 , the contact 40 is disposed radially outside the cover ring 39 and extends upward from the conductor portion 38.

[0074] The contact 40 may be configured to elastically contact the second chamber 20. The contact 40 has a spring 40s, for example, as shown in FIG. 20 . The contact 40 further has a contact portion 40c. The spring 40s and the contact portion 40c are conductive. The lower end of the spring 40s is fixed to the conductor portion 38. The spring 40s extends upward from the conductor portion 38. The contact portion 40c is fixed to the upper end of the spring 40s. The contact portion 40c is a portion that contacts the second chamber 20. A heat transfer sheet 100 is arranged between the contact portion 40c and the second chamber 20.

[0075] The second chamber 20 is disposed within the first chamber 10 and is configured to define a processing space S together with the substrate support 30. The second chamber 20 is formed of a metal such as aluminum. A corrosion-resistant film such as aluminum oxide or yttrium oxide may be formed on the surface of the second chamber 20.

[0076] The second chamber 20 is removable from the first chamber 10 and can be transported between the interior space of the first chamber 10 and the outside of the first chamber 10 via the opening 10o.

[0077] The semiconductor manufacturing apparatus 1 further includes a clamp 50 and a release mechanism 60. The clamp 50 is configured to releasably secure the second chamber 20 to the first chamber 10. The release mechanism 60 is configured to release the clamp 50 from securing the second chamber 20.

[0078] 19 , the second chamber 20 includes a ceiling 20c. The ceiling 20c extends substantially horizontally above the processing space S. The upper surface of the ceiling 20c abuts against the lower surface of the movable part 10m when the second chamber 20 is fixed to the first chamber 10. The ceiling 20c provides a plurality of gas holes 20h. The gas holes 20h penetrate the ceiling 20c and open toward the processing space S. Each of the gas holes 20h is in communication with a corresponding one of the gas holes 10h.

[0079] 19, the second chamber 20 further includes a side portion 20s. The side portion 20s extends laterally of the processing space S. The side portion 20s has a generally cylindrical shape. The side portion 20s extends downward from the edge of the ceiling portion 20c.

[0080] 19 , the second chamber 20 further includes a bottom 20b. The bottom 20b extends from the lower end of the side 20s in a direction intersecting the axis AX. A plurality of through holes are formed in the bottom 20b. When the second chamber 20, together with the substrate support 30, defines the processing space S, the bottom 20b abuts against the contact 40 via the heat transfer sheet 100.

[0081] The semiconductor manufacturing apparatus 1 further includes an exhaust device 70. The exhaust device 70 includes a pressure regulator such as an automatic pressure control valve and a pressure reducing pump such as a turbomolecular pump. The exhaust device 70 is connected to the bottom of the first chamber 10 below the bottom portion 20b.

[0082] The heat transfer sheet 100 in this embodiment may be disposed between the lower member 10a and the second chamber 20, and between the upper member 10b and the second chamber 20, as shown in FIG. 20 . This improves the thermal conduction performance between the lower member 10a and the second chamber 20 and the upper member 10b. Furthermore, because the CNTs 102 of the heat transfer sheet 100 have low electrical resistance, they can reduce the potential difference between the lower member 10a and the upper member 10b and the second chamber 20. In this case, the lower member 10a and the upper member 10b are an example of a first member, and the second chamber 20 is an example of a second member.

[0083] 20, the heat transfer sheet 100 in this embodiment may be disposed between the bottom 20b of the second chamber 20 and the contact portion 40c. This improves the heat conduction performance between the second chamber 20 and the contact portion 40c, and reduces the potential difference between the second chamber 20 and the contact portion 40c. In this case, the second chamber 20 is an example of a first member, and the contact portion 40c is an example of a second member.

[0084] 20 , the heat transfer sheet 100 in this embodiment may be disposed between the edge ring ER and the electrostatic chuck 36, and between the edge ring ER and the insulating portion 37. This improves the heat conduction performance between the edge ring ER and the electrostatic chuck 36 and the insulating portion 37, and also reduces the potential difference between the edge ring ER and the electrostatic chuck 36 and the insulating portion 37. In this case, the edge ring ER is an example of a first member, and the electrostatic chuck 36 and the insulating portion 37 are an example of a second member.

[0085] The heat transfer sheet 100 in this embodiment may be disposed between the substrate W and the electrostatic chuck 36. This improves the performance of heat conduction between the substrate W and the electrostatic chuck 36. In this case, the substrate W is an example of a first member, and the electrostatic chuck 36 is an example of a second member.

[0086] The embodiment has been described above. As described above, the heat transfer sheet (heat transfer sheet 100) in this embodiment is disposed between a first member (first member 200) and a second member (first member 200) and mediates heat exchange between the first member and the second member. The heat transfer sheet includes a plurality of carbon nanotubes (CNTs 102) and a metal film (metal film 103). The plurality of carbon nanotubes are oriented along the thickness direction of the heat transfer sheet. The metal film is provided at the tip of each carbon nanotube. This makes it possible to provide a heat transfer sheet with high thermal conductivity.

[0087] In the above-described embodiment, the first metal film (metal film 103a) formed on the tip of the first carbon nanotube (CNT 102a) among the plurality of carbon nanotubes and the second metal film (metal film 103b) formed on the tip of the second carbon nanotube (CNT 102b) among the plurality of carbon nanotubes can be displaced independently of each other in accordance with the deflection of the first carbon nanotube and the second carbon nanotube, thereby improving the thermal conductivity between the first member and the second member via the heat transfer sheet 100.

[0088] In the above-described embodiment, the metal film is made of, for example, aluminum, chromium, or titanium, thereby providing a heat transfer sheet with high thermal conductivity.

[0089] In the above-described embodiment, the metal film is formed on both the tips of the carbon nanotubes on one side of the heat transfer sheet and the tips of the carbon nanotubes on the other side of the heat transfer sheet, thereby further improving the thermal conductivity of the heat transfer sheet.

[0090] In the above-described embodiment, the first member and the second member are made of metal, thereby providing a heat transfer sheet with high thermal conductivity that is disposed between the two metals.

[0091] The above-described embodiment is a semiconductor manufacturing apparatus (semiconductor manufacturing apparatus 1) that includes a first member, a second member, and a heat transfer sheet. The heat transfer sheet can improve the thermal conductivity between the two members used in the semiconductor manufacturing apparatus.

[0092] The above-described embodiment is a method for manufacturing a heat transfer sheet that is disposed between a first member and a second member and mediates heat exchange between the first member and the second member, and includes steps a) (step S10), b) (step S12), and c) (step S14). In step a), a sheet is prepared on a substrate, on which a plurality of carbon nanotubes oriented along the thickness direction of the substrate are formed. In step b), a metal film is formed on the tip of each carbon nanotube. In step c), the heat transfer sheet containing a plurality of carbon nanotubes with a metal film formed on their tips is peeled off from the substrate. This allows for the provision of a heat transfer sheet with high thermal conductivity.

[0093] The embodiment described above further includes a step d) (step S11). The step d) is performed between the steps a) and b) to etch the tips of the carbon nanotubes. This further improves the thermal conductivity of the heat transfer sheet.

[0094] In the above-described embodiment, the tips of the carbon nanotubes are etched by plasma in step d), which allows the tips of the carbon nanotubes to be etched quickly.

[0095] In the above embodiment, in step b), the metal film is formed on the tip of each carbon nanotube under the condition that the metal film has a thickness in the range of 10 nm to 100 nm on the substrate, which makes it possible to prevent the metal films 103 formed on the tips of adjacent CNTs 102 from being integrated together.

[0096] In the above embodiment, in step b), a metal film is formed on the tip of each carbon nanotube by sputtering, which makes it possible to easily form a metal film of a desired thickness on the tips of multiple carbon nanotubes.

[0097] The above-described embodiment further includes a step e) (step S13). The step e) is performed between the steps b) and c) to heat-treat the heat transfer sheet. This improves the adhesion between the carbon nanotubes and the metal film, and further reduces the thermal resistance of the heat transfer sheet.

[0098] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0099] Furthermore, the following supplementary notes are disclosed regarding the above-described embodiments.

[0100] (Supplementary Note 1) A heat transfer sheet disposed between a first member and a second member and mediating heat exchange between the first member and the second member, the heat transfer sheet comprising: a plurality of carbon nanotubes oriented along a thickness direction of the heat transfer sheet; and a metal film provided on a tip of each of the carbon nanotubes. (Supplementary Note 2) The heat transfer sheet according to Supplementary Note 1, wherein a first metal film formed on a tip of a first carbon nanotube among the plurality of carbon nanotubes and a second metal film formed on a tip of a second carbon nanotube among the plurality of carbon nanotubes are displaceable independently of each other in accordance with bending of the first carbon nanotube and the second carbon nanotube. (Supplementary Note 3) The heat transfer sheet according to Supplementary Note 1 or 2, wherein the metal film is formed of aluminum, chromium, or titanium. (Supplementary Note 4) The heat transfer sheet according to any one of Supplementary Notes 1 to 3, wherein the metal film is formed on both the tips of the carbon nanotubes on one side of the heat transfer sheet and the tips of the carbon nanotubes on the other side of the heat transfer sheet. (Supplementary Note 5) The heat transfer sheet according to any one of Supplementary Notes 1 to 4, wherein the first member and the second member are made of metal. (Supplementary Note 6) A semiconductor manufacturing apparatus comprising the first member, the second member, and the heat transfer sheet according to any one of Supplementary Notes 1 to 5. (Supplementary Note 7) A method for manufacturing a heat transfer sheet that is arranged between a first member and a second member and mediates heat exchange between the first member and the second member, comprising the steps of: a) preparing a sheet on a substrate, the sheet having a plurality of carbon nanotubes formed on the substrate and oriented in the thickness direction of the substrate; b) forming a metal film on the tip of each of the carbon nanotubes; and c) peeling the heat transfer sheet including the plurality of carbon nanotubes with the metal film formed on their tips from the substrate. (Supplementary Note 8) The method for manufacturing a heat transfer sheet according to Supplementary Note 7, further comprising: d) a step that is performed between steps a) and b), of etching the tips of the plurality of carbon nanotubes. (Supplementary Note 9) The method for manufacturing a heat transfer sheet according to Supplementary Note 8, wherein in step d), the tips of the plurality of carbon nanotubes are etched using plasma.(Appendix 10) The method for manufacturing a heat transfer sheet according to any one of Appendices 7 to 9, wherein in step b), the metal film is formed on the tip of each of the carbon nanotubes under conditions such that the metal film has a thickness in the range of 10 nm to 100 nm on the substrate. (Appendix 11) The method for manufacturing a heat transfer sheet according to any one of Appendices 7 to 10, wherein in step b), the metal film is formed on the tip of each of the carbon nanotubes by sputtering. (Appendix 12) The method for manufacturing a heat transfer sheet according to any one of Appendices 7 to 11, further comprising: e) a step of heat treating the heat transfer sheet, which is carried out between step b) and step c).

[0101] REFERENCE SIGNS LIST 1 semiconductor manufacturing apparatus 100 heat transfer sheet 101 substrate 102 CNT 103 metal film 200 first member 201 second member 203 adhesive layer 300 heat source 301 cooling source

Claims

1. A heat transfer sheet disposed between a first member and a second member and mediating heat exchange between the first member and the second member, the heat transfer sheet comprising a plurality of carbon nanotubes oriented along the thickness direction of the heat transfer sheet, and a metal film provided at the tip of each of the carbon nanotubes.

2. A heat transfer sheet as described in claim 1, wherein a first metal film formed on the tip of a first carbon nanotube among the plurality of carbon nanotubes and a second metal film formed on the tip of a second carbon nanotube among the plurality of carbon nanotubes are capable of being displaced independently of each other in accordance with the bending of the first carbon nanotube and the second carbon nanotube.

3. The heat transfer sheet according to claim 1, wherein the metal film is formed of aluminum, chromium, or titanium.

4. The heat transfer sheet according to claim 1, wherein the metal film is formed on both the tips of the carbon nanotubes on one side of the heat transfer sheet and the tips of the carbon nanotubes on the other side of the heat transfer sheet.

5. The heat transfer sheet according to claim 1, wherein the first member and the second member are formed of metal.

6. A semiconductor manufacturing device comprising: the first member; the second member; and the heat transfer sheet according to claim 1.

7. A method for manufacturing a heat transfer sheet that is placed between a first member and a second member and mediates heat exchange between the first member and the second member, comprising the steps of: a) preparing a sheet on a substrate, on which a plurality of carbon nanotubes oriented along the thickness direction of the substrate are formed; b) forming a metal film on the tip of each of the carbon nanotubes; and c) peeling off the heat transfer sheet containing a plurality of carbon nanotubes with the metal film formed on their tips from the substrate.

8. The method for manufacturing a heat transfer sheet according to claim 7, further comprising: d) a step performed between steps a) and b) of etching the tips of the plurality of carbon nanotubes.

9. The method for manufacturing a heat transfer sheet according to claim 8, wherein in step d), the tips of the plurality of carbon nanotubes are etched using plasma.

10. A method for manufacturing a heat transfer sheet as described in claim 7, wherein in step b), the metal film is formed at the tip of each of the carbon nanotubes under conditions such that the metal film has a thickness in the range of 10 nm to 100 nm on the substrate.

11. The method for manufacturing a heat transfer sheet according to claim 7, wherein in step b), the metal film is formed on the tip of each of the carbon nanotubes by sputtering.

12. The method for manufacturing a heat transfer sheet according to claim 7, further comprising the step of: e) heat treating the heat transfer sheet, carried out between steps b) and c).

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