JP5768786B2 - Sheet-like structure and electronic device - Google Patents

Description

The present invention relates to a sheet-like structure and a manufacturing method thereof, particularly, relates to an electronic equipment using a sheet-like structure such as a sheet-like structures及Biko having a linear structure of carbon atoms.

  Electronic components used in a central processing unit (CPU) of a server or a personal computer are required to efficiently dissipate heat generated from a semiconductor element. For this reason, it has a structure in which a heat spreader made of a material having a high thermal conductivity such as copper is arranged through a heat conductive sheet such as an indium sheet provided immediately above the semiconductor element.

  However, the price of indium has soared due to a significant increase in demand for rare metals in recent years, and an alternative material that is cheaper than indium is expected. In addition, in terms of physical properties, the thermal conductivity (50 W / m · K) of indium is not high, and a material having a higher thermal conductivity in order to dissipate the heat generated from the semiconductor element more efficiently. Is desired.

  Against this background, a carbon element linear structure typified by carbon nanotubes has attracted attention as a material having higher thermal conductivity than indium. Carbon nanotubes not only have a very high thermal conductivity (1500 W / m · K), but also have excellent flexibility and heat resistance, and have a high potential as a heat dissipation material.

As a heat conductive sheet using carbon nanotubes, a heat conductive sheet in which carbon nanotubes are dispersed in a resin, or a heat conductive sheet in which a bundle of carbon nanotubes oriented and grown on a substrate is embedded with a resin or the like has been proposed.
JP 2005-150362 A JP 2006-147801 A JP 2006-303240 A

  However, the conventional thermal conductive sheet using carbon nanotubes cannot fully utilize the high thermal conductivity of carbon nanotubes.

An object of the present invention, provides thermal conductivity using linear structures of carbon atoms and electrical conductivity high-performance electronic equipment using a sheet-like structure, such as a very high sheet-like structures及Biko There is to do.

According to one aspect of the embodiment, a plurality of linear structures of carbon elements, a filling layer that fills gaps between the plurality of linear structures, and holds the plurality of linear structures, formed on at least one of the ends of the linear structure, it has a first coating consisting of indium, and a graphite layer formed between the first coating and the linear structure, the first There is provided a sheet-like structure in which one coating covers the upper surface of the graphite layer .

Further, according to another aspect of the embodiment, the graphite that bonds the linear structures of a plurality of carbon elements and the linear structures adjacent to each other to at least one end of the plurality of linear structures. And a sheet-like structure having a first coating covering the upper surface of the graphite layer .

Further, according to still another aspect of the embodiment, the heat generating unit, the heat dissipating unit that dissipates heat generated by the heat generating unit, the heat generating unit and the heat dissipating unit are disposed, and a plurality of carbon elements are disposed. A linear structure; a coating made of indium formed on at least one end of the plurality of linear structures; and a graphite layer formed between the coating and the linear structure. There is provided an electronic apparatus having a sheet-like structure in which the first film covers the upper surface of the graphite layer .

According to the disclosed sheet-like structure , a carbon element linear structure in which a coating of a material having a high thermal conductivity is formed at an end, and the linear structure is oriented in the film thickness direction of the sheet Since the structure is formed, the contact thermal resistance and contact resistance between the linear structure and the adherend to the sheet-like structure can be greatly reduced. Thereby, the thermal conductivity and electrical conductivity of the sheet-like structure can be improved.

[First Embodiment]
The carbon nanotube sheet and the manufacturing method thereof according to the first embodiment will be described with reference to FIGS.

  FIG. 1 is a perspective view showing the structure of the carbon nanotube sheet according to the present embodiment. FIG. 2 is a graph showing the results of the simulation of the relationship between the contact thermal resistance and the coating length of the coating 14. FIG. 3 is a schematic view showing a state in which the heating element and the heat radiating body are connected via the carbon nanotube sheet. 4 to 7 are perspective views illustrating the method of manufacturing the carbon nanotube sheet according to the present embodiment.

  First, the structure of the carbon nanotube sheet according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, the carbon nanotube sheet 10 according to the present embodiment includes a plurality of carbon nanotubes 12 having both ends coated with a coating 14 of a material having thermal conductivity and / or conductivity. It has a structure embedded in the filling layer 16 made of or the like.

The carbon nanotubes 12 are oriented in a direction perpendicular to the sheet surface. The carbon nanotube 12 may be either a single-walled carbon nanotube or a multi-walled carbon nanotube. The density of the carbon nanotubes 12 is desirably 1 × 10 ¹⁰ pieces / cm ² or more from the viewpoint of heat dissipation and electrical conductivity. The length of the carbon nanotube 12 is determined by the application of the carbon nanotube sheet 10 and is not particularly limited, but can be preferably set to a value of about 5 μm to 500 μm.

  The coating film 14 provided on the end of the carbon nanotube 12 is not particularly limited as long as it has a high thermal conductivity. From the viewpoint of improving the thermal conductivity of the carbon nanotube sheet 10 as a whole, it is desirable that the carbon nanotube sheet 10 be formed of a material having a higher thermal conductivity than the constituent material of the filling layer 16. Considering that the heat conductivity of a general resin material is about 1 (W / m · K), the coating film 14 formed on both surfaces of the carbon nanotube sheet 10 is a material having a high heat conductivity, for example, heat. It is effective to use a material having a conductivity of 0.1 (W / m · K) or more. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14 does not have to have a single layer structure, and may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium (Ti) and gold (Au).

  By providing the coating 14 with high thermal conductivity at the end of the carbon nanotube 12, the contact area of the carbon nanotube sheet 10 with respect to the adherend (heat radiating body, heating element) is increased as compared with the case where the coating 14 is not provided. can do. Thereby, the contact thermal resistance between the carbon nanotube 12 and the adherend is reduced, and the thermal conductivity of the carbon nanotube sheet 10 can be increased.

  Further, if a material having a low melting point, such as indium (melting point: about 157 ° C.) or low melting point solder, is used as the coating film 14, the coating film 14 can be reflowed after the carbon nanotube sheet 10 is brought into contact with the adherend. is there. Thereby, the unevenness | corrugation of the contact part between the carbon nanotube sheet 10 and a to-be-adhered body can be filled with the constituent material of the film 14, and the thermal conductivity and electroconductivity between these can be improved further.

FIG. 2 is a graph showing the results of the simulation of the relationship between the contact thermal resistance and the coating length of the coating 14. The horizontal axis is the coating length Lc of the film 14, and the vertical axis is the contact thermal resistance _Rth .

  FIG. 3 is a schematic diagram showing a state in which the heat generating body 50 and the heat radiating body 60 are connected via the carbon nanotube sheet 10. In FIG. 3, only one carbon nanotube 12 is shown as the carbon nanotube sheet 10. The coating 14 is formed so as to surround the end region of the carbon nanotube 12. The coating length Lc of the coating 14 is the length of the carbon nanotube 12 in the portion covered with the coating 14 as shown in FIG.

In the simulation of FIG. 2, it is assumed that carbon nanotubes 12 having a density of 1 × 10 ¹¹ pieces / cm ² , a thermal conductivity of 1000 W / m · K, and a length of 100 μm are formed in a region having a diameter of 100 μm. . Further, it was assumed that 30% of the contact area between the coating 14 made of gold and the carbon nanotubes 12 contributes to heat conduction.

  As shown in FIG. 2, the contact thermal resistance of the carbon nanotube 12 decreases as the coating length Lc of the coating 14 increases. In particular, when the coating length Lc of the film 14 is about 100 nm or less, the change in the contact thermal resistance with respect to the coating length Lc is extremely large, and the contact thermal resistance is reduced by one digit or more with a coating of several tens of nm or more.

When the carbon nanotubes 12 are grown at a density of about 1 × 10 ¹¹ pieces / cm ² , the coating length Lc is about three times the film thickness deposited on the end face of the carbon nanotubes 12.

When the carbon nanotubes 12 are grown at a density of about 1 × 10 ¹¹ pieces / cm ² , the interval between the carbon nanotubes 12 is about 30 to 50 nm. In this case, when the film thickness of the coating film 14 deposited on the end face of the carbon nanotube 12 is set to about 100 nm or more, the coating films 14 formed on the adjacent carbon nanotubes 12 are connected to each other, and the coating film 14 is connected to the carbon nanotube sheet 10. It is formed continuously on the surface of the film.

  The film thickness of the coating 14 can be appropriately set according to the characteristics required for the carbon nanotube sheet 10.

The minimum film thickness of the coating 14 can be defined from the viewpoint of the contact thermal resistance described above. For example, when the carbon nanotubes 12 are grown at a density of about 1 × 10 ¹¹ pieces / cm ^2, it is desirable that the film 14 has a thickness of about 30 nm or more (coating length Lc is about 100 nm or more). Thereby, compared with the case where the film 14 is not formed, the contact thermal resistance can be improved by one digit or more.

  The maximum film thickness of the coating 14 can be defined from the viewpoint of thermal conductivity required for the carbon nanotube sheet 10. When gold is used as the coating 14, the thermal conductivity of gold is about 300 [W / m · K], which is about 1/10 of the carbon nanotube 12. For this reason, if the coating film 14 is applied too thickly, the thermal conductivity of the carbon nanotube sheet 10 as a whole may be reduced.

  Whether the adjacent carbon nanotubes 12 are connected by the coating 14 or not can be selected depending on the use of the carbon nanotube sheet 10.

  When the adjacent carbon nanotubes 12 are not connected by the coating 14, each of the carbon nanotubes 12 is independent, and therefore has high flexibility. For this reason, the elasticity when contacting the adherend can be improved.

  On the other hand, when adjacent carbon nanotubes 12 are connected by the coating 14, the length of the carbon nanotubes 12 varies, and even when some of the carbon nanotubes 12 do not directly contact the adherend, All of the carbon nanotubes 12 can be used as the heat conductor by the lateral heat conduction / electric conduction via 14 and the heat conductivity can be improved.

  In the carbon nanotube sheet 10 according to the present embodiment, the surface of the coating 14 is not covered with the filling layer 16. Thereby, when the carbon nanotube sheet 10 is brought into contact with the heat radiating body or the heat generating body, the carbon nanotubes 12 are in direct contact with the heat radiating body or the heat generating body, so that the heat conduction efficiency can be greatly increased.

  Moreover, since the carbon nanotube 12 has conductivity, the carbon nanotube 12 can be used as a wiring body that penetrates the sheet by forming the coating film 14 with a conductive material. That is, the carbon nanotube sheet 10 according to the present embodiment can be used not only as a heat conductive sheet but also as a vertical wiring sheet. When the carbon nanotube sheet is used as a wiring sheet, the contact resistance between the carbon nanotube 12 and the adherend is reduced, and the conductivity of the carbon nanotube sheet 10 can be increased.

  The constituent material of the filling layer 16 is not particularly limited as long as it shows a liquid property at the time of embedding the carbon nanotube and can be cured thereafter. For example, an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or the like can be applied as the organic filler. As the inorganic filler, a coating-type insulating film forming composition such as SOG (Spin On Glass) can be applied. A metal material such as indium, solder, or a metal paste (eg, silver paste) can also be used. In addition, conductive polymers such as polyaniline and polythiophene can also be applied. In addition, when the carbon nanotube sheet 10 itself needs flexibility and flexibility, a filler that becomes rubbery or gelled after curing may be used.

  Moreover, you may disperse and mix an additive with the filled layer 16 as needed. As the additive, for example, a substance having high thermal conductivity or a substance having high conductivity can be considered. By dispersing and mixing an additive having high thermal conductivity in the filled layer 16 portion, the thermal conductivity of the filled layer 16 portion can be improved, and the thermal conductivity of the entire carbon nanotube sheet can be improved. In the case where the carbon nanotube sheet is used as a conductive sheet, the conductivity of the filling layer 16 portion can be improved by dispersing and mixing a highly conductive additive in the filling layer 16 portion. The conductivity as a whole can be improved. This is particularly effective when an insulating material having low thermal conductivity such as an organic filler is used as the filling layer 16. As the material having high thermal conductivity, carbon nanotube, metal material, aluminum nitride, silica, alumina, graphite, fullerene, or the like can be used. As the highly conductive material, carbon nanotubes, metal materials, and the like can be applied.

  Next, the method for manufacturing the carbon nanotube sheet according to the present embodiment will be explained with reference to FIGS.

  First, a substrate 30 used as a base for forming the carbon nanotube sheet 10 is prepared. As the substrate 30, a semiconductor substrate such as a silicon substrate, an alumina (sapphire) substrate, an MgO substrate, a glass substrate, or the like can be used. In addition, a thin film may be formed on these substrates. For example, a silicon substrate having a silicon oxide film with a thickness of about 300 nm can be used.

  The substrate 30 is peeled off after the carbon nanotubes 12 are formed. For this purpose, it is desirable that at least the surface in contact with the carbon nanotube 12 is formed of a material that can be easily peeled from the carbon nanotube 12 as the substrate 30. Alternatively, it is desirable that the carbon nanotube sheet 10 be formed of a material that can be selectively etched.

  Next, an Fe (iron) film of, eg, a 2.5 nm-thickness is formed on the substrate 30 by, eg, sputtering, and an Fe catalytic metal film 32 is formed (FIG. 4A).

  As the catalyst metal, in addition to Fe, Co (cobalt), Ni (nickel), Au (gold), Ag (silver), Pt (platinum), or an alloy containing at least one of these materials may be used. In addition to the metal film, metal fine particles prepared by controlling the size in advance using a differential mobility analyzer (DMA) or the like may be used as the catalyst. In this case, the metal species may be the same as in the case of the thin film.

In addition, as a base film of these catalyst metals, Mo (molybdenum), Ti (titanium), Hf (hafnium), Zr (zirconium), Nb (niobium), V (vanadium), TaN (tantalum nitride), TiSi _x (titanium) Silicide), Al (aluminum), Al ₂ O ₃ (aluminum oxide), TiO _x (titanium oxide), Ta (tantalum), W (tungsten), Cu (copper), Au (gold), Pt (platinum), Pd A film made of (palladium), TiN (titanium nitride), or an alloy containing at least one of these materials may be formed. For example, a stacked structure of Fe (2.5 nm) / Al (10 nm), a stacked structure of Co (2.6 nm) / TiN (5 nm), and the like can be applied. When metal fine particles are used, for example, a laminated structure such as Co (average diameter: 3.8 nm) / TiN (5 nm) can be applied.

  Next, carbon nanotubes are grown on the substrate 30 by, for example, hot filament CVD using the catalytic metal film 32 as a catalyst. The growth conditions of the carbon nanotube are, for example, using a mixed gas of acetylene and argon (partial pressure ratio 1: 9) as a source gas, the total gas pressure in the film forming chamber is 1 kPa, the hot filament temperature is 1000 ° C., and the growth time is 20 minutes. And As a result, it is possible to grow multi-walled carbon nanotubes having 3 to 6 layers (average of about 4 layers), a diameter of 4 to 8 nm (average of 6 nm), and a length of 80 μm (growth rate: 4 μm / min). The carbon nanotubes may be formed by other film forming methods such as a thermal CVD method and a remote plasma CVD method. The growing carbon nanotube may be a single-walled carbon nanotube. Moreover, as a carbon raw material, you may use hydrocarbons, such as methane and ethylene other than acetylene, alcohols, such as ethanol and methanol.

Thus, a plurality of carbon nanotubes 12 oriented in the normal direction of the substrate 30 (vertical orientation) are formed on the substrate 30 (FIG. 4B). The surface density of the carbon nanotubes 12 formed under the above growth conditions was about 1 × 10 ¹¹ pieces / cm ² .

  Next, a 10 nm thick titanium (Ti) film and a 300 nm thick gold (Au) film, for example, are deposited on the carbon nanotubes 12 by, for example, sputtering. As a result, a coating 14a having a laminated structure of Au / Ti is formed on the carbon nanotubes 12 (FIG. 5A). At this time, the coating length Lc at the end of the carbon nanotube 12 is about three times the deposited film thickness.

  The constituent material of the coating 14a is not particularly limited as long as it has a higher thermal conductivity than the constituent material of the filling layer 16. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14a, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14a may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  The reason why the Au / Ti laminated structure is used in the above example is that titanium has excellent adhesion to the carbon nanotubes 12. By forming a titanium film between the gold film and the carbon nanotube 12, the contact thermal resistance and the contact resistance between the carbon nanotube 12 and the coating film 14a can be reduced. From the viewpoint of improving adhesion, it is desirable to form a titanium film of about 10 nm or more.

  Next, a substrate (or sheet) 40 different from the substrate 30 is prepared as a substrate for transferring the carbon nanotubes 12 formed on the substrate 30. As the substrate 40, a semiconductor substrate such as a silicon substrate, an alumina (sapphire) substrate, an MgO substrate, a glass substrate, or the like can be used. In addition, a thin film may be formed on these substrates. For example, a silicon substrate having a silicon oxide film with a thickness of about 300 nm can be used.

  Next, an adhesive layer 42 is formed on the substrate 40. As the constituent material of the adhesive layer, a material having selective etching property with respect to the constituent material of the filling layer 16 to be formed later is applied. For example, when the filling layer 16 is formed of a non-water-soluble silicone resin, water-soluble polyvinyl alcohol (PVA) can be used as the adhesive layer 42.

  Next, the carbon nanotubes 12 formed on the substrate 30 are transferred onto the substrate 40 on which the adhesive layer 42 is formed (FIG. 5B). First, the board | substrate 30 and the board | substrate 40 are bonded together so that the formation surface of the film 14a and the adhesive material layer 42 may face each other. Next, the substrate 30 is peeled off from the interface between the substrate 30 and the carbon nanotubes 12. Since the adhesive force of the coating 14 a to the adhesive layer 42 is stronger than the adhesive force of the carbon nanotubes 12 to the substrate 30, the substrate 30 can be easily peeled from the interface with the carbon nanotubes 12. As a result, the carbon nanotubes 12 can be transferred onto the substrate 40.

  Next, a titanium (Ti) film having a thickness of 10 nm and a gold (Au) film having a thickness of 50 nm, for example, are deposited on the carbon nanotubes 12 transferred to the substrate 40 by, for example, sputtering. As a result, a coating film 14b having a laminated structure of Au / Ti is formed on the carbon nanotubes 12 (FIG. 6A). At this time, the coating length Lc at the end of the carbon nanotube 12 is about three times the deposited film thickness.

  The constituent material of the coating 14 b is not particularly limited as long as it has a higher thermal conductivity than the constituent material of the filling layer 16. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14b, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14b may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  Next, the gap between the carbon nanotubes 12 is filled with a filler to be the filling layer 16 by, for example, a dip method. For example, the substrate 40 onto which the carbon nanotubes 12 have been transferred is pressed against a substrate made of a silicone resin having a viscosity of 800 mPa · s, for example, at 1000 rpm for 20 seconds, for example, for 1 minute. As a result, the silicone resin as the filler is filled between the carbon nanotubes 12 to the same height as the carbon nanotubes 12 by capillary action.

  The filler is not particularly limited as long as it shows liquid properties and can be cured thereafter. For example, an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or the like can be applied as the organic filler. Further, as the inorganic filler, a coating type insulating film forming composition such as SOG can be applied. A metal material such as indium, solder, or a metal paste (eg, silver paste) can also be used. In addition, conductive polymers such as polyaniline and polythiophene can also be applied.

  When the carbon nanotubes 12 are formed on the entire surface of the substrate 40, when the filler penetrates between the carbon nanotubes 12, the individual carbon nanotubes 12 aggregate together, and the carbon nanotubes 12 are originally retained. The orientation may have been lost, and the shape may change, for example, it may fall sideways. However, in this embodiment, since the coating 14 is formed at both ends of the carbon nanotube 12, the shape change of the carbon nanotube 12 can be suppressed and aggregation can be prevented.

  Next, the filler filled between the carbon nanotubes 12 is cured to form a filling layer 16 (FIG. 6B). For example, when a photocurable material such as an acrylic resin is used as the filler, the filler can be cured by light irradiation. In addition, when a thermosetting material such as an epoxy resin or a silicone resin is used as the filler, the filler can be cured by heat treatment. In the case of an epoxy resin, it can be cured by heat treatment at 150 ° C. for 1 hour, for example. In the case of a silicone resin, it can be cured by heat treatment at 200 ° C. for 1 hour, for example.

  If the coating 14b on the carbon nanotubes 12 is not sufficiently exposed or covered with the filling layer 16 after the filling layer 16 is cured, the coating 14b is formed by chemical mechanical polishing or oxygen plasma ashing. The upper filling layer 16 may be removed. When the residue of the adhesive layer 42 remains on the coating 14b, there is an effect of removing this residue.

  Next, the carbon nanotubes 12 and the filling layer 16 whose both ends are covered with the coating 14 are peeled off from the substrate 40 to obtain the carbon nanotube sheet 10 (FIG. 7).

  For example, the carbon nanotube sheet 10 can be easily peeled by selectively etching the adhesive layer 42 with respect to the filling layer 16. For example, when the filling layer 16 is formed of a silicone resin and the adhesive layer 42 is formed of polyvinyl alcohol, the carbon nanotube sheet is dissolved by immersing in water or warm water to dissolve the adhesive layer 42. 10 can be peeled off.

  As described above, according to the present embodiment, a coating made of a material having a high thermal conductivity is formed at the end of the carbon nanotube, so that the contact thermal resistance and the contact resistance between the carbon nanotube and the adherend of the sheet are reduced. It can be greatly reduced. Thereby, the thermal conductivity and electrical conductivity of the carbon nanotube sheet can be improved.

[Second Embodiment]
A method of manufacturing the carbon nanotube sheet according to the second embodiment will be described with reference to FIGS. Components similar to those of the carbon nanotube sheet and the manufacturing method thereof according to the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  8 and 9 are perspective views illustrating the method of manufacturing the carbon nanotube sheet according to the present embodiment.

  The method of manufacturing the carbon nanotube sheet according to the present embodiment is the same as the method of manufacturing the carbon nanotube sheet according to the first embodiment, except that the method of transferring the carbon nanotubes 12 onto the substrate 40 is different. The constituent materials of each constituent part and the detailed manufacturing method are the same as in the case of the first embodiment.

  First, in the same manner as the carbon nanotube sheet manufacturing method according to the first embodiment shown in FIGS. 4A to 5A, the carbon nanotubes 12 are formed on the substrate 30 and at the ends of the carbon nanotubes 12. The coating 14a is formed.

  Next, a substrate (or sheet) 40 different from the substrate 30 is prepared as a substrate for transferring the carbon nanotubes 12 formed on the substrate 30.

  Next, a sacrificial layer 44 and a layer 46 of a material that can be thermocompression bonded to the coating 14 a (hereinafter referred to as “thermocompression layer 46”) are formed on the substrate 40. As a constituent material of the thermocompression bonding layer 46, for example, when the surface of the coating 14a is formed of gold, gold can be applied. As a constituent material of the sacrificial layer 44, a material having selective etching property with respect to the thermocompression bonding layer 46 is applied. In the case where the thermocompression bonding layer 46 is made of gold, for example, titanium can be applied.

  Next, the carbon nanotubes 12 formed on the substrate 30 are transferred onto the substrate 40 on which the adhesive layer 42 is formed (FIG. 8A). First, the substrate 30 and the substrate 40 are overlaid so that the formation surface of the coating 14a and the thermocompression bonding layer 46 face each other. Next, pressure is applied between the substrate 30 and the substrate 40 while heating, and the coating 14a and the thermocompression bonding layer 46 are thermocompression bonded. Next, the substrate 30 is peeled off from the interface between the substrate 30 and the carbon nanotubes 12. Since the adhesive force of the coating 14 a to the thermocompression bonding layer 46 is stronger than the adhesive force of the carbon nanotubes 12 to the substrate 30, the substrate 30 can be easily peeled from the interface with the carbon nanotubes 12. As a result, the carbon nanotubes 12 can be transferred onto the substrate 40.

  Next, in the same manner as in the first embodiment, on the carbon nanotubes 12 transferred to the substrate 40, for example, by sputtering, for example, a titanium (Ti) film having a thickness of 10 nm and for example, gold (Au) having a thickness of 50 nm are formed. Deposit film. As a result, a coating 14b having a laminated structure of Au / Ti is formed on the carbon nanotubes 12 (FIG. 8B).

  Next, in the same manner as in the first embodiment, the filling layer 16 is formed to fill the gaps between the carbon nanotubes 12 (FIG. 9A).

  Next, the carbon nanotubes 12 and the filling layer 16 whose both ends are covered with the coating film 14 are peeled from the substrate 40 to obtain the carbon nanotube sheet 10 (FIG. 9B).

  For example, the carbon nanotube sheet 10 can be easily peeled by selectively etching the sacrificial layer 44 with respect to the thermocompression bonding layer 46. For example, when the thermocompression bonding layer 46 is made of gold and the sacrificial layer 44 is made of titanium, the sacrificial layer 44 is dissolved and the carbon nanotube sheet 10 is peeled off by immersing in a hydrofluoric acid aqueous solution. be able to.

[Third Embodiment]
The carbon nanotube sheet and the manufacturing method thereof according to the third embodiment will be described with reference to FIGS. Components similar to those of the carbon nanotube sheet and the manufacturing method thereof according to the first and second embodiments shown in FIGS. 1 to 9 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 10 is a perspective view showing the structure of the carbon nanotube sheet according to the present embodiment. FIG. 11 is a perspective view illustrating the method of manufacturing the carbon nanotube sheet according to the present embodiment.

  First, the structure of the carbon nanotube sheet according to the present embodiment will be explained with reference to FIG.

  The carbon nanotube sheet 10 according to the present embodiment has a graphite layer 20 between the carbon nanotubes 12 and the coating 14 as shown in FIG. The graphite layer 20 is formed of graphite having a layered structure parallel to the surface of the sheet, and is formed by being directly connected to one end side of the carbon nanotube 12. The thickness of the graphite layer 14 is about several nm to several hundred nm.

  Graphite has a thermal conductivity of 500 times or more compared to a resin material (thermal conductivity: about 1 (W / m · K)). Therefore, by providing the graphite layer 20, the heat dissipation in the direction parallel to the surface of the sheet can be greatly improved by 500 times or more compared with the case where the graphite layer 14 is not formed.

  When the carbon nanotube sheet 10 according to the present embodiment is formed between the heat generating body and the heat radiating body, the carbon nanotube sheet 10 is desirably disposed so that the end of the carbon nanotube 12 on the graphite layer 20 side is located on the heat generating body side. By doing in this way, the heat from a heat generating body can be rapidly propagated by the graphite layer 20 in the direction parallel to the sheet surface. Thereby, the heat dissipation efficiency toward the heat dissipation body via the carbon nanotubes 12 can be increased.

  Next, the manufacturing method of the carbon nanotube sheet according to the present embodiment will be explained with reference to FIG. In addition, the constituent material of each component part and the detailed manufacturing method are the same as that of the case of 1st Embodiment.

  First, a substrate 30 used as a base for forming the carbon nanotube sheet 10 is prepared. As the substrate 30, various substrates described in the first embodiment can be used.

Next, a TiN film having a thickness of, for example, 5 nm and a Co film having a thickness of, for example, 2.6 nm are sequentially deposited on the substrate 30 by, for example, sputtering to form a catalytic metal film 32 having a Co / TiN stacked structure. . In addition to TiN, other materials containing Ti, such as Ti (titanium) and TiO ₂ (titanium oxide), can be used as the base film of the catalytic metal film 38.

  Next, the carbon nanotubes 12 whose upper surface is covered with the graphite layer 20 are grown on the substrate 30 by, for example, thermal CVD, using the catalytic metal film 32 as a catalyst (FIG. 11A).

  The carbon nanotubes 12 whose upper surface is covered with the graphite layer 20 can be formed by growing at a relatively low temperature of about 450 ° C. to 510 ° C. using a source gas of hydrocarbons such as acetylene, methane, and ethylene. it can. For example, a mixed gas of acetylene and argon (partial pressure ratio 1: 9) is used as the source gas, the total gas pressure in the deposition chamber is 1 kPa, the temperature is 450 ° C. to 510 ° C., and the growth time is 30 minutes. Thereby, it is possible to grow multi-walled carbon nanotubes having 3 to 6 layers (average of about 4 layers), diameter of 4 to 8 nm (average of 6 nm), and length of 20 μm. Further, a graphite layer 20 having a thickness of 18 nm is formed on the carbon nanotube 12.

  The carbon nanotube 12 whose upper surface is covered with the graphite layer 20 can be formed by appropriately controlling the film thickness of the catalytic metal film 38 (film thickness of the Co film) and the film formation temperature. The inventors of the present application have studied that the Co film thickness is set to 2.0 nm to 7.0 nm, and growth is performed at a film formation temperature of 350 ° C. to 560 ° C. so that the upper surface is covered with the graphite layer 20. It has been found that broken carbon nanotubes 12 can be formed.

  Further, the thickness of the formed graphite layer can also be controlled by the thickness of the Co film and the film formation temperature. For example, when the film formation temperature is 510 ° C., a 4 nm-thick graphite layer could be formed when the Co film thickness was 2.1 nm. Further, when the thickness of the Co film was 2.6 nm, a graphite layer having a thickness of 18 nm could be formed. Further, when the thickness of the Co film was 3.6 nm, a graphite layer having a thickness of 30 nm could be formed. Further, when the film formation temperature was 450 ° C. and the Co film thickness was 3.6 nm, a graphite layer having a thickness of 20 nm could be formed.

  The mechanism by which the carbon nanotubes 12 whose upper surface is covered with the graphite layer 20 is not clear, but the inventors of the present application infer as follows.

  In this embodiment, the carbon nanotubes 12 are grown at a relatively low temperature. For this reason, it is considered that the Co film of the catalytic metal film 32 is not sufficiently aggregated in the initial growth process, and graphite is uniformly grown on the catalytic metal film 32. Thereafter, the growth of the carbon nanotubes is started together with the aggregation of the Co film. As a result, it is considered that the carbon nanotubes 12 whose upper surfaces are covered with the graphite layer 20 are formed.

  When forming the carbon nanotube 12 whose upper surface is covered with the graphite layer 20, the graphite layer 20 is formed in about 1 second in the initial stage of growth. The length of the carbon nanotube 12 can be arbitrarily controlled by the growth time.

  Next, in the same manner as in the first embodiment, for example, a titanium (Ti) film with a thickness of 10 nm and a gold (Au) film with a thickness of 50 nm, for example, are deposited by sputtering, for example. As a result, a coating 14a having a laminated structure of Au / Ti is formed on the graphite layer 20 (FIG. 11B).

  Next, in the same manner as in the first or second embodiment, after the carbon nanotubes 12 are transferred onto the substrate 40, a coating 14 b is formed on the other end side of the carbon nanotubes 12.

  Next, in the same manner as in the first embodiment, after forming the filling layer 16 between the carbon nanotubes 12, the substrate 40 is peeled off to complete the carbon nanotube sheet 10 according to the present embodiment.

  As described above, according to the present embodiment, a coating made of a material having a high thermal conductivity is formed at the end of the carbon nanotube, so that the contact thermal resistance and the contact resistance between the carbon nanotube and the adherend of the sheet are reduced. It can be greatly reduced. In addition, since the graphite layer is formed by directly connecting to one end of the carbon nanotube, the thermal conductivity and conductivity in the direction parallel to the surface of the sheet can be improved. Thereby, the thermal conductivity and electrical conductivity of the carbon nanotube sheet can be improved.

[Fourth Embodiment]
The carbon nanotube sheet and the manufacturing method thereof according to the fourth embodiment will be described with reference to FIG. Components similar to those of the carbon nanotube sheet and the manufacturing method thereof according to the first to third embodiments shown in FIGS. 1 to 11 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  FIG. 12 is a plan view and a schematic sectional view showing the structure of the carbon nanotube sheet according to the present embodiment. FIG. 12A is a plan view showing the structure of the carbon nanotube sheet according to the present embodiment, and FIG. 12B is a cross-sectional view taken along the line AA ′ of FIG.

  In the first to third embodiments, the carbon nanotubes 12 are uniformly formed on the entire surface of the sheet. However, the carbon nanotubes 12 do not necessarily have to be uniformly formed on the entire surface of the sheet. For example, as shown in FIG. 12, a carbon nanotube bundle 22 including a plurality of carbon nanotubes 12 whose ends are covered with a coating (not shown). May be arranged spaced apart from each other. In this way, when forming the filling layer 16 between the carbon nanotubes, the permeability of the filler is increased, and the shape change such as the carbon nanotube 12 falling sideways is effectively suppressed, and the carbon nanotubes are originally retained. It is possible to easily maintain the orientation.

  The necessary gap between the carbon nanotube bundles 22 varies depending on the viscosity of the filler used as the filling layer 16 and cannot be determined unconditionally. However, the gap between the carbon nanotubes 12 constituting each of the carbon nanotube bundles 22 can be determined. Can be set to a sufficiently wide width, preferably about 0.1 μm to 200 μm. However, as the distance between the carbon nanotube bundles 22 increases, the surface density of the carbon nanotubes in the sheet surface decreases, that is, the thermal conductivity of the sheet decreases. Further, the surface density of the carbon nanotubes in the sheet surface also varies depending on the size of the carbon nanotube bundle 22. Therefore, the interval between the carbon nanotube bundles 22 needs to be appropriately set in consideration of the size of the carbon nanotube bundles 22 in accordance with the thermal conductivity required for the sheet.

  The planar shape of each carbon nanotube bundle 22 is not limited to the circular shape shown in FIG. As a planar shape of the carbon nanotube bundle 22, in addition to a circle, for example, a polygon such as a triangle, a quadrangle, and a hexagon may be used. Further, the arrangement of the plurality of carbon nanotube bundles 12 is not limited to the circular close-packed array as shown in FIG.

  The carbon nanotube sheet manufacturing method according to the present embodiment is the same as that in the first to third embodiments except that the carbon nanotubes 12 are selectively grown on a predetermined region on the substrate 30 (region where the carbon nanotube bundles 22 are to be formed). It is the same as the case of.

  In order to perform selective growth of the carbon nanotubes 12, the catalytic metal film 32 may be selectively formed in a region where the carbon nanotube bundles 22 are to be formed. For selective formation of the catalytic metal film 32, for example, a lift-off method using a photoresist film or a method of sputtering the catalytic metal with the surface of the substrate 30 covered with a metal mask can be applied.

  When the carbon nanotube bundles 22 as shown in FIG. 12 are formed, in the formation process of the filling layer 16, the filler first spreads over the entire surface of the substrate 40 along the gaps of the carbon nanotube bundles 22. After that, the filler penetrates into the carbon nanotube bundle 22. For this reason, the filler previously filled between the carbon nanotube bundles 22 serves as a supporter for maintaining the shape of the carbon nanotubes 12 when the filler penetrates into the carbon nanotube bundles 22. The shape change of the bundle 22 is suppressed. Therefore, coupled with the effect of the coating film 14 described above, the aggregation of the carbon nanotubes 12 can be further effectively prevented.

  As described above, according to the present embodiment, a coating made of a material having a high thermal conductivity is formed at the end of the carbon nanotube, so that the contact thermal resistance and the contact resistance between the carbon nanotube and the adherend of the sheet are reduced. It can be greatly reduced. In addition, since a plurality of carbon nanotube bundles spaced apart from each other are formed, it is possible to prevent a change in the shape of the carbon nanotube bundles when forming the packed layer. Thereby, the thermal conductivity and electrical conductivity of the carbon nanotube sheet can be improved.

[Fifth Embodiment]
The carbon nanotube sheet and the manufacturing method thereof according to the fifth embodiment will be described with reference to FIGS. Components similar to those of the carbon nanotube sheet and the manufacturing method thereof according to the first to fourth embodiments shown in FIGS. 1 to 12 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 13 is a perspective view showing the structure of the carbon nanotube sheet according to the present embodiment. 14 and 15 are perspective views illustrating the method of manufacturing the carbon nanotube sheet according to the present embodiment.

  First, the structure of the carbon nanotube sheet according to the present embodiment will be explained with reference to FIG.

  As shown in FIG. 13, the carbon nanotube sheet 10 according to the present embodiment includes a plurality of carbon nanotubes 12 whose both ends are covered with a coating 14 of a material having thermal conductivity and / or conductivity. The coatings 14 formed on the ends of the adjacent carbon nanotubes 12 are connected to each other. That is, the coating 14 is continuously formed on both surfaces of the carbon nanotube sheet 10 over the entire surface.

The carbon nanotubes 12 are oriented in a direction perpendicular to the sheet surface. The carbon nanotube 12 may be either a single-walled carbon nanotube or a multi-walled carbon nanotube. The density of the carbon nanotubes 12 is desirably 1 × 10 ¹⁰ pieces / cm ² or more from the viewpoint of heat dissipation and electrical conductivity. The length of the carbon nanotube 12 is determined by the application of the carbon nanotube sheet 10 and is not particularly limited, but can be preferably set to a value of about 5 μm to 500 μm.

  The coating film 14 formed on both surfaces of the carbon nanotube sheet 10 is not particularly limited as long as it is a material having a high thermal conductivity, for example, a material having a thermal conductivity of 0.1 (W / m · K) or more. Absent. A material having a thermal conductivity of 0.1 (W / m · K) or higher is sufficiently higher than the thermal conductivity (about 1 (W / m · K)) of a general resin material. This is based on the purpose of the material. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14 does not have to have a single layer structure, and may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium (Ti) and gold (Au).

  By providing the coating 14 with high thermal conductivity at the end of the carbon nanotube 12, the contact area of the carbon nanotube sheet 10 with respect to the adherend (heat radiating body, heating element) is increased as compared with the case where the coating 14 is not provided. can do. Thereby, the contact thermal resistance between the carbon nanotube 12 and the adherend is reduced, and the thermal conductivity of the carbon nanotube sheet 10 can be increased.

When the carbon nanotubes 12 are grown at a density of about 1 × 10 ¹¹ pieces / cm ² , the interval between the carbon nanotubes 12 is approximately 30 to 50 nm. In this case, when the film thickness of the coating film 14 deposited on the end face of the carbon nanotube 12 is set to about 100 nm or more, the coating films 14 formed on the adjacent carbon nanotubes 12 are connected to each other, and the coating film 14 is connected to the carbon nanotube sheet 10. It is formed continuously on the surface of the film.

  Even when adjacent carbon nanotubes 12 are connected by the coating 14 to cause variations in the length of the carbon nanotubes 12 and some of the carbon nanotubes 12 do not directly contact the adherend, the coating 14 is interposed. All the carbon nanotubes 12 can be used as the heat conductor by the lateral heat conduction / electric conduction, and the heat conductivity can be improved.

  Moreover, since the carbon nanotube 12 has conductivity, the carbon nanotube 12 can be used as a wiring body that penetrates the sheet by forming the coating film 14 with a conductive material. That is, the carbon nanotube sheet 10 according to the present embodiment can be used not only as a heat conductive sheet but also as a vertical wiring sheet. When the carbon nanotube sheet is used as a wiring sheet, the contact resistance between the carbon nanotube 12 and the adherend is reduced, and the conductivity of the carbon nanotube sheet 10 can be increased.

  Further, if a material having a low melting point, such as indium or low melting point solder, is used as the coating 14, the coating 14 can be reflowed after the carbon nanotube sheet 10 is brought into contact with the adherend. Thereby, the unevenness | corrugation of the contact part between the carbon nanotube sheet 10 and a to-be-adhered body can be filled up with the film 14, and the thermal conductivity and electroconductivity between these can be improved further.

  In the carbon nanotube sheet 10 according to the present embodiment, unlike the carbon nanotube sheets according to the first to fourth embodiments, the filling layer 16 is not formed. This is because the carbon nanotubes 12 can be supported by the coating film 14 by forming the coating film 14 over the entire surface of the sheet. The main role of the filling layer 16 is to support the carbon nanotubes 12 while maintaining the orientation. Therefore, in the carbon nanotube sheet 10 according to the present embodiment in which the carbon nanotubes 12 are supported by the coating 14, the filling layer 16 is not always necessary. However, the filling layer 16 may be formed also in the carbon nanotube sheet 10 according to the present embodiment.

  The film thickness of the coating 14 can be appropriately set according to the characteristics required for the carbon nanotube sheet 10. From the viewpoint of supporting the carbon nanotubes 12, it is desirable to have a film thickness of about several μm or more.

  Next, the method for manufacturing the carbon nanotube sheet according to the present embodiment will be explained with reference to FIGS. In addition, the constituent material of each component part and the detailed manufacturing method are the same as that of the case of 1st Embodiment.

  First, for example, the carbon nanotubes 12 are formed on the substrate 30 in the same manner as the carbon nanotube sheet manufacturing method according to the first embodiment shown in FIGS. 4A to 4B (FIG. 14A). . Note that the carbon nanotubes 12 having the graphite layer formed on the upper end may be formed in the same manner as in the third embodiment.

  Next, an indium (In) film having a thickness of, for example, several μm is deposited on the carbon nanotubes 12 by, eg, vapor deposition. As a result, an In film is deposited on the carbon nanotubes 12 and the In films formed on the adjacent carbon nanotubes 12 are connected to each other to form a continuous In film 14a over the entire surface (FIG. 14). (B)).

  The constituent material of the coating 14a is not particularly limited as long as it is a material having high thermal conductivity. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14a, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14a may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  Next, the carbon nanotube 12 and the coating 14a are peeled from the substrate 30 (FIG. 15A).

  Next, an indium (In) film having a thickness of, for example, several μm is deposited on the carbon nanotube 12 on the peeling surface side of the substrate 30 by, for example, vapor deposition. As a result, an In film is deposited on the carbon nanotubes 12, and the In films formed on the adjacent carbon nanotubes 12 are connected to each other, so that a continuous In coating 14b is formed over the entire surface.

  The constituent material of the coating 14b is not particularly limited as long as the material has high thermal conductivity. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14a, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14a may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  Thus, the carbon nanotube sheet 10 according to the present embodiment is completed (FIG. 15B).

  As described above, according to the present embodiment, a coating made of a material having a high thermal conductivity is formed at the end of the carbon nanotube, so that the contact thermal resistance and the contact resistance between the carbon nanotube and the adherend of the sheet are reduced. It can be greatly reduced. Thereby, the thermal conductivity and electrical conductivity of the carbon nanotube sheet can be improved.

[Sixth Embodiment]
The carbon nanotube sheet and the manufacturing method thereof according to the sixth embodiment will be described with reference to FIGS. Components similar to those of the carbon nanotube sheet and the manufacturing method thereof according to the first to fifth embodiments shown in FIGS. 1 to 15 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 16 is a perspective view showing the structure of the carbon nanotube sheet according to the present embodiment. 17 and 18 are process cross-sectional views illustrating the method of manufacturing the carbon nanotube sheet according to the present embodiment. FIG. 19 is a schematic view showing a method of tilting the carbon nanotube bundle.

  First, the structure of the carbon nanotube sheet according to the present embodiment will be explained with reference to FIG.

  As shown in FIG. 16, the carbon nanotube sheet 10 according to the present embodiment includes a plurality of carbon nanotube bundles 22 and coatings 14 formed at both ends thereof. The coatings 14 formed on the ends of the adjacent carbon nanotube bundles 22 are connected to each other. That is, the coating 14 is continuously formed on both surfaces of the carbon nanotube sheet 10 over the entire surface.

  The plurality of carbon nanotube bundles 22 extend from one surface side (lower side in the drawing) of the carbon nanotube sheet 10 to the other surface side (upper side in the drawing) in the same direction intersecting the direction perpendicular to the sheet surface. Oriented to tilt. The carbon nanotube bundles 18 adjacent to each other in the inclined direction are in contact with each other in the vicinity of at least one end (upper side in the drawing).

Each carbon nanotube bundle 22 has a plurality of carbon nanotubes (not shown) oriented along the orientation direction of the carbon nanotube bundle 22. The carbon nanotubes included in each carbon nanotube bundle 22 may be either single-walled carbon nanotubes or multi-walled carbon nanotubes. The density of the carbon nanotubes 12 included in the carbon nanotube bundle 18 is desirably 1 × 10 ¹⁰ pieces / cm ² or more from the viewpoint of heat dissipation and electrical conductivity. The length of the carbon nanotube 12 is determined by the application of the carbon nanotube sheet 10 and is not particularly limited, but can be preferably set to a value of about 5 μm to 500 μm.

  The coating film 14 formed on both surfaces of the carbon nanotube sheet 10 is not particularly limited as long as it is a material having a high thermal conductivity, for example, a material having a thermal conductivity of 0.1 (W / m · K) or more. . A material having a thermal conductivity of 0.1 (W / m · K) or higher is sufficiently higher than the thermal conductivity (about 1 (W / m · K)) of a general resin material. This is based on the purpose of the material. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14 does not have to have a single layer structure, and may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium (Ti) and gold (Au).

  Thus, in the carbon nanotube sheet 10 according to the present embodiment, the carbon nanotube bundles 22 are oriented so as to go from one surface side of the sheet to the other surface side. Therefore, the carbon nanotube sheet with excellent thermal conductivity and electrical conductivity in the thickness direction of the sheet is realized by fully exhibiting the characteristics of carbon nanotubes with high thermal conductivity and electrical conductivity along the orientation direction. can do. In addition, since the carbon nanotubes also have conductivity, the carbon nanotube bundle 22 can be used as a wiring body that penetrates the sheet. That is, the carbon nanotube sheet 10 according to the present embodiment can be used not only as a heat conductive sheet but also as a vertical wiring sheet.

  Further, in the carbon nanotube sheet 10 according to the present embodiment, the carbon nanotube bundles 22 are inclined and oriented in a direction intersecting the direction perpendicular to the surface of the sheet, and the carbon nanotube bundles 22 adjacent to each other in the inclined direction are They are in contact with each other in the vicinity of at least one end. Thereby, the thermal conductivity and electrical conductivity in the direction perpendicular to the surface of the sheet can be further increased, and the thermal conductivity and electrical conductivity in the direction parallel to the surface of the sheet can be improved.

  When growing a plurality of carbon nanotube bundles 22, the lengths of all the carbon nanotube bundles 22 are not necessarily equal. When the length of the carbon nanotube bundle 22 varies, only the long carbon nanotube bundle 22 comes into contact with the adherend, and there is a possibility that the other carbon nanotube bundle 18 cannot be used as a heat conductor / electric conductor.

  By bringing adjacent carbon nanotube bundles 22 into contact with each other, the carbon nanotube bundles 22 that are not in direct contact with the adherend are caused to function indirectly as thermal conductors / electric conductors via the other carbon nanotube bundles 22. Can do. Moreover, by using the manufacturing method described later, the uniformity of the height of the inclined carbon nanotube bundle 22 can be increased, and the contact area with the adherend can be increased. In addition, inclining the carbon nanotube bundle 22 has an effect of improving the density of the carbon nanotube bundle 22. Such various effects can further enhance the thermal conductivity and electrical conductivity in the direction perpendicular to the surface of the sheet.

  Further, when the adjacent carbon nanotube bundles 22 are in contact with each other, a path of heat conduction and electric conduction through the carbon nanotube bundles 22 is also formed in a direction parallel to the surface of the sheet, and in a direction parallel to the surface of the sheet. Thermal conductivity and electrical conductivity can also be improved.

  Moreover, by providing the coating 14 with high thermal conductivity on both surfaces of the carbon nanotube sheet 10, compared with the case where the coating 14 is not provided, the contact area of the carbon nanotube sheet 10 with respect to the adherend (heat radiator, heating element). Can be increased. Thereby, the contact thermal resistance between the carbon nanotube bundle 22 and the adherend is reduced, and the thermal conductivity of the carbon nanotube sheet 10 can be increased.

  The coating 14 has the effect of increasing the contact area between the carbon nanotube bundles 22 and the adherend, and the effect of ensuring the connection between the adjacent carbon nanotube bundles 22. Therefore, by providing the coating 14, the contact thermal resistance / contact resistance between the carbon nanotube sheet 10 and the adherend can be reduced.

  Further, if a material having a low melting point, such as indium or low melting point solder, is used as the coating 14, the coating 14 can be reflowed after the carbon nanotube sheet 10 is brought into contact with the adherend. Thereby, the unevenness | corrugation of the contact part between the carbon nanotube sheet 10 and a to-be-adhered body can be filled up with the film 14, and the thermal conductivity and electroconductivity between these can be improved further.

  In the carbon nanotube sheet 10 according to the present embodiment, the filling layer 16 is not formed as in the case of the fifth embodiment. This is because the carbon nanotube bundle 22 (carbon nanotube) can be supported by the coating film 14 by forming the coating film 14 over the entire surface of the sheet. The main role of the packed layer 16 is to support the carbon nanotube bundle while maintaining the orientation. Therefore, in the carbon nanotube sheet 10 according to the present embodiment in which the carbon nanotube bundle 22 is supported by the coating 14, the filling layer 16 is not necessarily required. However, the filling layer 16 may be formed also in the carbon nanotube sheet 10 according to the present embodiment.

  The film thickness of the coating 14 can be appropriately set according to the characteristics required for the carbon nanotube sheet 10. From the viewpoint of supporting the carbon nanotube bundle 22, it is desirable to have a film thickness of about several μm or more.

  Next, the method for manufacturing the carbon nanotube sheet according to the present embodiment will be explained with reference to FIGS. In addition, the constituent material of each component part and the detailed manufacturing method are the same as that of the case of 1st Embodiment.

  First, a substrate 30 used as a base for forming the carbon nanotube sheet 10 is prepared.

  Next, a catalytic metal film 32 is selectively formed on the substrate 30 by, for example, a lift-off method using a photoresist film. A region where the catalytic metal film 32 is formed is a region where the carbon nanotube bundle 22 is to be formed (FIG. 17A). The method for forming the catalytic metal film 32 is not limited to the lift-off method. For example, a metal mask having an opening in a region where the carbon nanotube bundle 22 is to be formed may be used. The catalytic metal film 32 can be selectively formed in the region where the carbon nanotube bundles 22 are to be formed by sputtering the catalytic metal while covering the surface of the substrate 30 with the metal mask.

  The planar layout of the catalyst metal 32 is not particularly limited. For example, as shown in FIG. 12A, a layout in which the formation regions of circular carbon nanotube bundles 22 are closely packed can be applied.

  Next, carbon nanotubes are grown on the substrate 30 by, for example, hot filament CVD using the catalytic metal film 32 as a catalyst. Thus, the carbon nanotube bundle 22 having a plurality of carbon nanotubes oriented in the normal direction (vertical orientation) of the substrate 30 is selectively formed on the region of the substrate 30 where the catalytic metal film 32 is formed (FIG. 17 ( b)).

  Next, the carbon nanotube bundle 22 grown in this manner is tilted in a direction intersecting with the direction perpendicular to the surface of the sheet (FIG. 17C).

  In the present embodiment, when tilting the carbon nanotube bundle 22, an apparatus that can apply a uniform pressure to the surface of the substrate 30 and can move the substrate 30 in the horizontal direction while applying the pressure is used. Such an apparatus is not particularly limited, but for example, a flip chip bonder apparatus can be used. Here, a method of tilting the carbon nanotube bundle 22 will be described by taking as an example a case where a flip chip bonder device is used.

  First, the substrate 30 on which the carbon nanotube bundles 22 are grown is placed on the stage 50 of the flip chip bonder apparatus (see FIG. 19).

Next, a first pressure of about several N / cm ² is applied in a direction perpendicular to the surface of the substrate 30 (downward in the figure) from the carbon nanotube bundle 22 by the pressure head 52 of the flip chip bonder device. Apply (see FIG. 19). For example, as shown in FIG. 19, the pressure head 52 has a surface parallel to the substrate 30.

  Next, with the first pressure applied to the carbon nanotube bundle 22, the pressure head 52 is moved in the first direction (rightward in the drawing) parallel to the surface of the substrate 30 by about several tens of microns, for example, 30 μm. (See FIG. 19).

Next, the pressure applied by the pressure head 52 is increased from the first pressure to a second pressure of about 10 to 50 N / cm ² higher than the first pressure. At this time, the pressure may change intermittently from the first pressure to the second pressure, or may gradually change gradually from the first pressure to the second pressure, or from the first pressure. You may change gradually to a 2nd pressure in steps.

  Next, in a state where the second pressure is applied to the carbon nanotube bundle 18, the pressure head 52 is further moved about several millimeters, for example, 2 mm, in the first direction parallel to the surface of the substrate 30.

  In this way, by applying a pressure to the carbon nanotube bundle 22 and moving the pressure head 52, the carbon nanotube bundle 22 can be tilted in the first direction and adjacent carbon nanotube bundles 22 can be connected to each other. it can.

  In the above-described method, the pressure applied to the carbon nanotube bundle 22 and the movement of the pressure head are performed in two stages. This is to tilt the carbon nanotube bundle 22 to a desired shape while preventing the carbon nanotube bundle 22 from being broken.

  When a pressure is applied in the vertical direction in the initial state in which the carbon nanotube bundles 22 are vertically aligned, if the applied pressure is too strong, the carbon nanotube bundles 22 may be crushed or broken and broken. Therefore, as a first step, the pressure head 52 is pressed against the upper end of the carbon nanotube bundle 22 at a pressure at which the carbon nanotube bundle 22 is not destroyed, and the pressure head 52 is brought into close contact with the carbon nanotube bundle 22. In this state, the carbon nanotube bundle 22 is slightly tilted by moving the pressure head 52 in the horizontal direction. Since the pressure head 52 is in contact with the carbon nanotube bundle 22, tilting the carbon nanotube bundle 22 has an effect of making the height variation of the carbon nanotube bundle 22 uniform.

  When the carbon nanotube bundle 22 is tilted, the pressure applied to the carbon nanotube bundle 22 is dispersed, so that a higher pressure can be applied without breaking the carbon nanotube bundle 22. Therefore, as a second stage, the pressure head 52 is pressed against the upper end of the carbon nanotube bundle 22 at a second pressure higher than the first pressure, and in this state, the pressure head 52 is moved in the horizontal direction, whereby carbon nanotubes are obtained. Tilt the bundle 22 to the desired shape.

  The pressure applied to the carbon nanotube bundle 22 and the moving direction and moving amount of the pressure head 52 can be controlled while monitoring with a flip chip bonder device.

The inventors of the present application and others have made a sample in which a carbon nanotube bundle 22 having carbon nanotubes having a length of 100 μm and a surface density of 1 × 10 ¹¹ / cm ² is formed on a substrate 30 having a size of 2 × 3 cm ² at an area ratio of 63%. When examined, a pressure of about several N / cm ² , for example, 3 N / cm ² was suitable as the first pressure. As the second pressure, a pressure of about several tens N / cm ² , for example, 40 N / cm ² was suitable.

  Note that the first and second pressures applied to the carbon nanotube bundle 22 are the length of the carbon nanotube bundle 22, the surface density of the carbon nanotubes in the carbon nanotube bundle 22, and the carbon nanotubes so that the carbon nanotube bundle 22 is not destroyed. It is desirable to set appropriately according to the surface density of the bundle 22 and the like. Further, it is desirable that the horizontal movement distance of the pressure head 52 is appropriately set according to the length of the carbon nanotube bundle 22, the degree of inclination necessary for the carbon nanotube bundle 22, and the like.

  In the above description, the pressure head 52 is moved when the carbon nanotube bundle 22 is tilted. However, the pressure head 52 may be moved relative to the substrate 30. That is, the stage 50 may be fixed and the pressure head 52 may be moved, the pressure head 52 may be fixed and the stage 50 may be moved, or the stage 50 and the pressure head 52 may be moved in opposite directions. You may move on.

  Next, after the carbon nanotube bundle 22 is tilted in this manner, an indium (In) film having a thickness of, for example, several μm is deposited on the carbon nanotube bundle 22 by, for example, an evaporation method. As a result, an In film is deposited on the carbon nanotube bundles 22 and the In films formed on the adjacent carbon nanotubes 12 are connected to each other to form a continuous In coating 14a over the entire surface (FIG. 18 (a)).

  The constituent material of the coating 14a is not particularly limited as long as it is a material having high thermal conductivity. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14a, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14a may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  Next, the carbon nanotube bundle 22 and the coating 14a are peeled from the substrate 30 (FIG. 18B).

  Next, an indium (In) film having a thickness of, for example, several μm is deposited on the carbon nanotube bundle 22 on the peeling surface side of the substrate 30 by, for example, vapor deposition. As a result, an In film is deposited on the carbon nanotube bundles 22 and the In films formed on the adjacent carbon nanotube bundles 22 are connected to each other to form a continuous In coating 14b over the entire surface.

  The constituent material of the coating 14b is not particularly limited as long as the material has high thermal conductivity. When the carbon nanotube sheet 10 is used for electric conduction, a conductive material such as a metal or an alloy can be applied. As a constituent material of the coating 14a, for example, copper (Cu), nickel (Ni), gold (Au), indium (In), low melting point solder, or the like can be used. The coating 14a may have a single layer structure of these metals, or may have a laminated structure of two layers or three or more layers such as a laminated structure of titanium and gold as described above.

  Thus, the carbon nanotube sheet 10 according to the present embodiment is completed (FIG. 18C).

  In the drawing of the present embodiment, a state in which a catalytic metal film 32 used for growth is formed at the lower end of the carbon nanotube bundle 22 is shown. Since the catalytic metal film 32 is aggregated and taken into the carbon nanotubes during the growth of the carbon nanotubes, it does not actually remain in the state shown in the figure, and the carbon nanotube bundle 18 is exposed on the lower surface of the sheet. To do. Further, the catalytic metal film 32 may be removed at the same time when the substrate 30 is peeled off.

  As described above, according to the present embodiment, a coating made of a material having high thermal conductivity is formed at the end of the carbon nanotube bundle, so that the contact thermal resistance and contact between the carbon nanotube bundle and the adherend of the sheet are formed. Resistance can be greatly reduced. Thereby, the thermal conductivity and electrical conductivity of the carbon nanotube sheet can be improved. In addition, the carbon nanotube bundles are oriented from one surface of the sheet to the other surface, and adjacent carbon nanotube bundles are connected to each other, so that the direction perpendicular to the sheet surface and the sheet surface are horizontal. A sheet having high thermal conductivity and high electrical conductivity in any direction can be formed.

[Seventh Embodiment]
An electronic apparatus according to a seventh embodiment of the present invention will be described with reference to FIG.

  FIG. 20 is a schematic cross-sectional view showing the structure of the electronic apparatus according to the present embodiment.

  In the present embodiment, an electronic apparatus to which the carbon nanotube sheet according to the first to sixth embodiments is applied as a heat conductive sheet will be described.

  A semiconductor element 106 such as a CPU is mounted on the circuit board 100 such as a multilayer wiring board. The semiconductor element 106 is electrically connected to the circuit board 100 via the solder bumps 102, and an underfill 104 is filled between the circuit board 100 and the semiconductor element 106.

  A heat spreader 110 for diffusing heat from the semiconductor element 106 is formed on the semiconductor element 106 so as to cover the semiconductor element 106. A carbon nanotube sheet 108 according to the first or second embodiment is formed between the semiconductor element 106 and the heat spreader 110.

  On the heat spreader 110, a heat sink 114 for radiating heat transmitted to the heat spreader 110 is formed. A carbon nanotube sheet 112 is formed between the heat spreader 110 and the heat sink 114.

  As described above, in the electronic apparatus according to the present embodiment, between the semiconductor element 106 and the heat spreader 110 and between the heat spreader 110 and the heat sink 114, that is, between the heat generating portion and the heat radiating portion, the first to sixth embodiments. Either one of the carbon nanotube sheets 108 and 112 is provided.

  As described above, in the carbon nanotube sheets according to the first to sixth embodiments, the carbon nanotubes are oriented perpendicular to the film surface of the sheet, and the thermal conductivity in the perpendicular direction is extremely high. In addition, the carbon nanotube sheets according to the fifth and sixth embodiments have the coatings 14 formed on both surfaces thereof, and can greatly reduce the contact thermal resistance.

  Therefore, by using the disclosed carbon nanotube sheet as a heat conductive sheet formed between the semiconductor element 106 and the heat spreader 110 and between the heat spreader 110 and the heat sink 114, the heat generated from the semiconductor element 106 is efficiently horizontal. While spreading in the direction, the heat spreader 110 and the heat sink 114 can be transmitted in the vertical direction, and the heat dissipation efficiency can be improved. Thereby, the reliability of an electronic device can be improved.

  As described above, according to this embodiment, the carbon nanotube sheets according to the first to sixth embodiments are disposed between the semiconductor element and the heat spreader and between the heat spreader and the heat sink. Can be greatly improved. Thereby, the thermal radiation efficiency of the heat | fever emitted from a semiconductor element can be improved, and the reliability of an electronic device can be improved.

[Eighth Embodiment]
An electronic apparatus according to an eighth embodiment of the present invention will be described with reference to FIG.

  FIG. 21 is a schematic sectional view showing the structure of the electronic apparatus according to the present embodiment.

  In the present embodiment, an electronic apparatus in which the carbon nanotube sheet according to the fifth or sixth embodiment is applied as a heat conductive sheet will be described.

  A circuit board 100 such as a multilayer wiring board is mounted on the printed wiring board 130. The circuit board 100 is electrically connected to the printed wiring board 130 via solder bumps 132.

  A semiconductor element 106 such as a CPU is mounted on the circuit board 100. The semiconductor element 106 is electrically connected to the circuit board 100 via the solder bumps 102.

  A heat spreader 110 for diffusing heat from the semiconductor element 106 is formed on the semiconductor element 106 so as to cover the semiconductor element 106. A carbon nanotube sheet 108 according to the first or second embodiment is formed between the semiconductor element 106 and the heat spreader 110. The heat spreader 110 is bonded to the circuit board 100 with an organic sealant 116, for example.

  As described above, in the electronic apparatus according to the present embodiment, the carbon nanotube sheet 108 according to the first to sixth embodiments is provided between the semiconductor element 106 and the heat spreader 110, that is, between the heat generating portion and the heat radiating portion. .

  As described above, in the carbon nanotube sheets according to the first to sixth embodiments, the carbon nanotubes are oriented in the direction perpendicular to the film surface of the sheet, and the coating for reducing the contact thermal resistance is provided at both ends thereof. 14 is formed, and the thermal conductivity in the direction perpendicular to the surface is extremely high.

  Therefore, by using the disclosed carbon nanotube sheet as a heat conductive sheet formed between the semiconductor element 106 and the heat spreader 110, the heat spreader 110 and the heat sink 114 are efficiently spread in the horizontal direction while the heat generated from the semiconductor element 106 is efficiently spread. Can be transmitted in the vertical direction, and the heat radiation efficiency can be improved. Thereby, the reliability of an electronic device can be improved.

  Further, as the coating 14 formed on both surfaces of the sheet, other components of the electronic device, for example, a material having a lower melting point than the material of the solder bumps 102 and 132 and the organic sealant 116, such as indium or low melting point solder, The heat dissipation efficiency can be further increased.

  That is, if the coating 14 is formed of a material having a lower melting point than other components of the electronic device, for example, a low melting point material such as indium or low melting point solder, the coating 14 is reflowed without damaging the other components. can do. Thereby, the unevenness | corrugation of the interface of the semiconductor element 106 and the carbon nanotube sheet | seat 108 and the interface of the carbon nanotube sheet | seat 108 and the heat spreader 110 can be filled with the constituent material of the film 14, and the contact thermal resistance between these is further reduced. be able to.

  The heat treatment step for reflowing the coating 14 can be performed, for example, after the heat spreader 110 is bonded on the circuit board 100 or after the circuit board 100 is mounted on the printed wiring board 130.

  Thus, according to this embodiment, since the carbon nanotube sheets according to the first to sixth embodiments are disposed between the semiconductor element and the heat spreader, the thermal conductivity between them can be greatly improved. it can. Thereby, the thermal radiation efficiency of the heat | fever emitted from a semiconductor element can be improved, and the reliability of an electronic device can be improved.

[Ninth Embodiment]
An electronic apparatus according to a ninth embodiment of the present invention will be described with reference to FIG.

  FIG. 22 is a schematic cross-sectional view showing the structure of the electronic apparatus according to the present embodiment.

  In the present embodiment, an electronic apparatus in which the carbon nanotube sheet according to the first to sixth embodiments is applied as a heat conductive sheet that also serves as a conductive sheet will be described.

  As shown in FIG. 22, a high power amplifier (HPA) 120 used in a radio communication base station or the like is incorporated in a package 122 and joined to a heat sink 124 on the back surface of the package 122. Heat generated from the high-power amplifier 120 is radiated to the heat sink 124 through the back surface of the package 122. At the same time, the package 122 is also used as an electrical ground (ground plane), and needs to be electrically connected to the heat sink 124. Therefore, it is desirable to use a good conductor for electricity and heat for joining the package 122 and the heat sink 124.

  Therefore, as shown in FIG. 22, by using the carbon nanotube sheet 126 according to any one of the first to sixth embodiments at the joint between the package 122 and the heat sink 124, the package 122 and the heat sink 124 are electrically connected. Can be connected. In addition, heat generated from the high-power amplifier 120 can be efficiently transmitted to the heat sink 124, and heat dissipation efficiency can be improved. Thereby, the reliability of an electronic device can be improved.

  As described above, according to the present embodiment, the carbon nanotube sheet in which the carbon nanotubes are oriented in the film thickness direction of the sheet is disposed between the package of the high-power amplifier and the heat sink. It can be greatly improved. Thereby, the heat radiation efficiency of the heat | fever emitted from a high output amplifier can be improved. Thereby, the reliability of an electronic device can be improved. Further, the high-power amplifier and a heat sink as a ground can be electrically connected.

[Modified Embodiment]
The present invention is not limited to the above embodiment, and various modifications are possible.

  For example, in the above-described embodiment, the carbon nanotube using the carbon nanotube is shown as an example of the sheet-like structure using the linear structure of the carbon element, but the sheet-like structure using the linear structure of the carbon element is shown. However, the present invention is not limited to this. Examples of the carbon element linear structure include carbon nanowires, carbon rods, and carbon fibers in addition to carbon nanotubes. These linear structures are the same as the carbon nanotubes except that their sizes are different. The present invention can also be applied to a sheet-like structure using these linear structures.

  In the first to sixth embodiments, the coating film 14 is provided on both surfaces of the carbon nanotube sheet 10. However, the coating film 14 may be provided only on one surface side of the carbon nanotube sheet 10. When the coating 14 is formed only on one surface side of the carbon nanotube sheet 10, when the carbon nanotube sheet 10 is used as a heat conductive sheet, the surface of the carbon nanotube sheet 10 on the coating 14 side is disposed on the heating element side. It is desirable to dispose the carbon nanotube sheet 10 in such a manner. In order to form the coating film 14 on only one surface of the carbon nanotube sheet 10, the filling layer 16 may be formed after the step shown in FIG.

  In the first to fourth embodiments, the filling layer 16 is formed between the carbon nanotubes 12 or between the carbon nanotube bundles 22, but the filling layer 16 is not necessarily formed. The packed layer 16 is mainly for supporting the plurality of carbon nanotubes 12 or the carbon nanotube bundles 22 and maintaining the state of the sheet. Accordingly, when the coating 14 can sufficiently support the carbon nanotubes 12 such as when the coating 14 is continuously formed on the surface of the sheet, the filling layer 16 is not necessarily formed.

  In the sixth embodiment, the carbon nanotube bundle 22 is tilted. For example, in the carbon nanotube sheet 10 in which the carbon nanotubes 12 are formed on the entire surface as in the first to third and fifth embodiments, the carbon nanotubes 12 are It may be tilted. The carbon nanotubes 12 can be tilted by the method described in the sixth embodiment, for example.

  In addition, the constituent materials and manufacturing conditions described in the above embodiment are not limited to the descriptions, and can be appropriately changed according to the purpose and the like.

  Further, the purpose of using the carbon nanotube sheet is not limited to that described in the above embodiment. The disclosed carbon nanotube sheet is, for example, a CPU heat dissipation sheet, a radio communication base station high output amplifier, a radio communication terminal high output amplifier, an electric vehicle high output switch, a server, a personal computer, etc. Can be applied. Moreover, it is applicable to a vertical wiring sheet and various applications using the high allowable current density characteristic of carbon nanotubes.

  Regarding the above embodiment, the following additional notes are disclosed.

(Appendix 1) Linear structures of a plurality of carbon elements;
A filling layer filled in a gap between the plurality of linear structures and holding the plurality of linear structures;
And a first film made of a material having a higher thermal conductivity than that of the constituent material of the filling layer, the sheet-like structure being formed at at least one end of the plurality of linear structures.

(Supplementary note 2) In the sheet-like structure according to supplementary note 1,
The sheet-like structure characterized in that the first coating couples the linear structures adjacent to each other.

(Appendix 3) Linear structures of a plurality of carbon elements;
A first film formed on at least one end of the plurality of linear structures, having a thermal conductivity of 0.1 W / m · K or more and bonding adjacent linear structures to each other; A sheet-like structure comprising:

(Appendix 4) In the sheet-like structure according to any one of appendices 1 to 3,
The sheet-like structure further comprising a graphite layer formed between the first film and the linear structure.

(Supplementary note 5) In the sheet-like structure according to any one of supplementary notes 1 to 4,
A sheet-like structure further comprising a second film formed on the other end of the plurality of linear structures.

(Appendix 6) In the sheet-like structure according to any one of appendices 1 to 5,
The plurality of linear structures are arranged at a first interval, and form a plurality of linear structure bundles arranged at a second interval greater than the first interval. A sheet-like structure.

(Supplementary note 7) In the sheet-like structure according to any one of supplementary notes 1 to 6,
The plurality of linear structures are oriented in the film thickness direction of the sheet.

(Appendix 8) In the sheet-like structure according to any one of appendices 1 to 7,
Each of the plurality of linear structures is inclined with respect to the film thickness direction of the sheet, and the adjacent linear structures are in contact with each other.

  A sheet-like structure characterized by that.

(Supplementary note 9) In the sheet-like structure according to supplementary note 5,
The second coating film has a thermal conductivity of 0.1 W / m · K or more.

(Supplementary Note 10)
A heat dissipating part for dissipating heat generated by the heat generating part;
A sheet-like structure disposed between the heat generating part and the heat radiating part and having a plurality of carbon element linear structures and a coating formed on at least one end of the plurality of linear structures. And an electronic device.

(Additional remark 11) In the electronic device of Additional remark 10,
The electronic apparatus according to claim 1, wherein the sheet-like structure further includes a filling layer that fills a gap between the plurality of linear structures and holds the plurality of linear structures.

(Additional remark 12) In the electronic device of Additional remark 10,
The coating is formed to bond adjacent linear structures to each other,
A plurality of the linear structures are held by the coating film.

(Supplementary Note 13) A step of forming a catalytic metal film on the first substrate;
Growing a plurality of carbon element linear structures on the first substrate using the catalytic metal film as a catalyst;
Forming a first coating on the ends of the plurality of linear structures;
Peeling the first substrate from the interface between the plurality of linear structures and the first substrate after bonding the second substrate on the first film;
Filling a filler between the linear structures and forming a filling layer;
And a step of removing the second substrate.

(Additional remark 14) In the manufacturing method of the sheet-like structure of Additional remark 13,
After peeling off the first substrate,
A method for producing a sheet-like structure, further comprising a step of forming a second film on end portions of the plurality of linear structures exposed by peeling off the first substrate.

(Appendix 15) Forming a catalytic metal film on a substrate;
Growing a linear structure of a plurality of carbon elements on the substrate using the catalytic metal film as a catalyst;
Forming a first film on the ends of the plurality of linear structures so as to bond adjacent linear structures to each other;
Peeling the substrate from the interface between the plurality of linear structures and the substrate;
The manufacturing method of the sheet-like structure characterized by having.

(Additional remark 16) In the manufacturing method of the sheet-like structure of Additional remark 15,
After peeling off the substrate,
The manufacturing method of the sheet-like structure characterized by further including the process of forming a 2nd film on the edge part of the said some linear structure exposed by peeling the said board | substrate.

(Supplementary note 17) In the method for manufacturing a sheet-like structure according to any one of supplementary notes 13 to 16,
In the step of growing the plurality of linear structures, the linear structure whose ends are covered with a graphite layer is grown. A method for producing a sheet-like structure.

(Supplementary Note 18) A heat generating portion and a heat radiating portion that dissipates heat generated by the heat generating portion are formed at a plurality of carbon element linear structures and at least one end of the plurality of linear structures. Bonding through a sheet-like structure having a coated film;
And a step of performing a heat treatment at a temperature higher than the melting point of the coating film and reflowing the coating film.

(Supplementary note 19) In the method for manufacturing an electronic device according to supplementary note 18,
The method of manufacturing an electronic device, wherein the sheet-like structure further includes a filling layer that is filled in a gap between the plurality of linear structures and holds the plurality of linear structures.

(Additional remark 20) In the manufacturing method of the electronic device of Additional remark 18,
The coating is formed to bond adjacent linear structures to each other,
A plurality of the linear structures are held by the coating film. A method for manufacturing an electronic device, wherein:

FIG. 1 is a perspective view showing the structure of the carbon nanotube sheet according to the first embodiment. FIG. 2 is a graph showing the result of the simulation of the relationship between the contact thermal resistance and the coating length of the film. FIG. 3 is a schematic view showing a state in which the heating element and the heat radiating body are connected via the carbon nanotube sheet. FIG. 4 is a perspective view (No. 1) showing the method of manufacturing the carbon nanotube sheet according to the first embodiment. FIG. 5 is a perspective view (No. 2) showing the carbon nanotube sheet manufacturing method according to the first embodiment. FIG. 6 is a perspective view (No. 3) showing the method of manufacturing the carbon nanotube sheet according to the first embodiment. FIG. 7 is a perspective view (No. 4) showing the carbon nanotube sheet manufacturing method according to the first embodiment. FIG. 8 is a perspective view (No. 1) showing the carbon nanotube sheet manufacturing method according to the second embodiment. FIG. 9 is a perspective view (No. 2) showing the carbon nanotube sheet manufacturing method according to the second embodiment. FIG. 10 is a perspective view showing the structure of the carbon nanotube sheet according to the third embodiment. FIG. 11 is a process cross-sectional view illustrating the method of manufacturing the carbon nanotube sheet according to the third embodiment. FIG. 12 is a plan view and a schematic sectional view showing the structure of the carbon nanotube sheet according to the fourth embodiment. FIG. 13 is a perspective view showing the structure of the carbon nanotube sheet according to the fifth embodiment. FIG. 14 is a perspective view (No. 1) showing the carbon nanotube sheet manufacturing method according to the fifth embodiment. FIG. 15 is a perspective view (No. 2) showing the carbon nanotube sheet manufacturing method according to the fifth embodiment. FIG. 16 is a schematic cross-sectional view showing the structure of the carbon nanotube sheet according to the sixth embodiment. FIG. 17 is a process cross-sectional view (part 1) illustrating the method of manufacturing the carbon nanotube sheet according to the sixth embodiment. FIG. 18 is a process cross-sectional view (part 2) illustrating the method of manufacturing the carbon nanotube sheet according to the sixth embodiment. FIG. 19 is a schematic view showing a method of tilting a carbon nanotube bundle in the sixth embodiment. FIG. 20 is a schematic cross-sectional view showing the structure of an electronic device according to the seventh embodiment. FIG. 21 is a schematic sectional view showing the structure of an electronic device according to the eighth embodiment. FIG. 22 is a schematic sectional view showing the structure of an electronic device according to the ninth embodiment.

DESCRIPTION OF SYMBOLS 10 ... Carbon nanotube sheet 12 ... Carbon nanotube 14 ... Film 16 ... Filling layer 20 ... Graphite layer 22 ... Carbon nanotube bundle 30, 40 ... Substrate 42 ... Adhesive layer 44 ... Sacrificial layer 46 ... Thermocompression bonding layer 50 ... Stage 52 ... Addition Pressure head 100 ... Circuit boards 102, 132 ... Solder bumps 104 ... Underfill 106 ... Semiconductor elements 108, 112, 126 ... Carbon nanotube sheets 110 ... Heat spreaders 114, 124 ... Heat sink 120 ... High power amplifier 122 ... Package 130 ... Printed wiring board

Claims (2)

A linear structure of a plurality of carbon elements;
A filling layer filled in a gap between the plurality of linear structures and holding the plurality of linear structures;
A first film made of a material having a higher thermal conductivity than a constituent material of the filling layer , formed on at least one end of the plurality of linear structures;
A graphite layer formed between the first coating and the linear structure;
The sheet-like structure, wherein the first film covers an upper surface of the graphite layer. A heating part;
A heat dissipating part for dissipating heat generated by the heat generating part;
A plurality of carbon element linear structures disposed between the heat generating section and the heat radiating section, and a filling layer filled in gaps between the plurality of linear structures and holding the plurality of linear structures. A first film made of a material having a thermal conductivity higher than that of the constituent material of the filling layer, formed on at least one end of the plurality of linear structures, the first film, and the linear An electronic apparatus comprising: a sheet-like structure including a graphite layer formed between the structure and the first film covering an upper surface of the graphite layer.

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