JP2016017014A - Powder having high thermal conductivity, high electrical insulation and low thermal expansion, heat radiation structure manufactured from the same, and method of manufacturing the powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder from which a heat radiation structure of a semiconductor device can be manufactured at low cost, the powder having high thermal conductivity, high electrical insulation and low thermal expansion; a method of manufacturing the powder; and a heat radiation structure manufactured from the powder, such as a heat sink, a heat spreader a print circuit board, a heat radiation sheet, an encapsulation material or the like.SOLUTION: There is provided a method for manufacturing a powder coated with AlN or SiN11, which is generated by depositing nanoparticles of Al or Si on inorganic particles 12, while stirring them, by a physical vapor deposition method, and heat-treating them under nitrogen atmosphere, and manufacturing various heat radiation structures using the powder. In the powder coated with AlN or SiN11, the inorganic particles 12 are AlO, Mg(OH), MgO, MgCO, CaCOand SiOhaving an average particle diameter of 0.1 to 100 μm, and the nanoparticles 11 having an average particle diameter of 0.1 to 100 nm are deposited with a thickness of 0.1 to 100 μm on the inorganic particles 12 and then heat-treated for 3 to 6 hours at 400 to 600°C under nitrogen atmosphere.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat dissipation material with high thermal conductivity, electrical insulation, and low thermal expansion suitable for a heat dissipation structure. More specifically, it can be used for heat dissipation structures such as heat sinks, heat spreaders, printed circuit boards, heat dissipation sheets, and sealing materials that constitute semiconductor devices, and has high thermal conductivity, electrical insulation, and low thermal expansion. The present invention relates to a conductive powder, a heat dissipation structure using the same, and a method for producing the powder.

  Semiconductor elements such as transistors, integrated circuits, resistors, and capacitors are still required to have higher functions and higher integration, and the amount of heat generated by the semiconductor elements is enormous. This heat leads to a malfunction or a decrease in life of a semiconductor device in which a semiconductor element is incorporated, destruction due to generation of stress, and the like. For this reason, for example, in inverter power modules used for various power control, the amount of heat generated has increased rapidly due to increased control power and higher integration, and excellent heat dissipation and matching of the thermal expansion coefficient with the Si chip are required. It has been. Also, LEDs used in various display / lighting devices have high heat generation density, and the semiconductor laser itself is vulnerable to heat. Therefore, as with power modules, it has excellent heat dissipation and thermal expansion with compound semiconductors such as GaAs and GaN. Coefficient matching is required. Furthermore, such heat not only causes deterioration of the characteristics of the semiconductor device itself incorporating the semiconductor element, but may also have various adverse effects such as malfunction, ignition, and destruction of the entire electronic device incorporating it. Therefore, in order to ensure performance, safety, and reliability, heat dissipation measures are indispensable than ever, and thermal design in current electronic equipment design plays an important role that is comparable to electrical design. Yes.

  In general, heat is transferred in three ways: conduction, convection, and radiation. For example, in the typical semiconductor device shown in FIG. 1, mainly (1) from the external terminal of the semiconductor 6 via the solder ball 8 A path 1 that conducts from the package external terminal to the motherboard via the solder balls 8 to the build-up board 9, and from the semiconductor 6 to the sealing material 7, (2) side face of the build-up board 9, side face of the mother board 10, and sealing There are a path 2 that is conducted from the stopper 7 to the air and dissipates heat by convection, and (3) a path 3 that radiates air from the top of the package surface. In general, heat radiation from a printed circuit board (build-up board 9, motherboard 10) having a surface area that is much larger than the surface area of the package greatly contributes to heat radiation generated from the semiconductor device. On the other hand, heat dissipation from the package surface is less than about 10% of the total. Furthermore, heat dissipation due to radiation is almost negligible. Of course, the development of paints and insulating materials that increase the heat radiation rate is also progressing so that the heat radiation that is almost impossible in the case of mirror-finished aluminum is greatly improved by the black alumite treatment. Is not obtained. FIG. 1 shows an example in which a heat spreader 4 that promotes heat radiation from the package surface and has excellent thermal conductivity is provided via an adhesive 5.

  In any case, these three heat dissipation paths are ultimately due to convective heat transfer to the air, so that a forced cooling device such as a fan is provided, or a heat sink having heat dissipation fins that increase the contact surface area with the air. However, it is not a factor that can be applied to all electronic devices because of the increase in size and cost of electronic equipment. In addition, the design of the semiconductor device such as the design of the semiconductor chip, the structure and dimensions of the semiconductor package, and the structure and density of the semiconductor mounting circuit board is also important, but the heat dissipation effect is not sufficient. Therefore, even now, the idea to increase the heat conduction in the path leading to the release of heat into the air is the most effective for heat dissipation, has become the mainstream of heat dissipation measures, has excellent thermal conductivity and low thermal expansion The development is centered on the material itself. This improves the thermal conductivity of the material itself that constitutes the semiconductor device and essentially eliminates mechanical effects such as thermal stress unless the thermal expansibility is suppressed. This is because no heat is dissipated. (Non-Patent Document 1)

  Heat sinks such as heat sinks and heat spreaders, which are components that enhance heat conduction, have become incompatible with conventional copper (Cu) and aluminum (Al), which have a high coefficient of thermal expansion. From the viewpoint of not only the thermal conductivity but also the thermal expansion coefficient tailored to the semiconductor or the mechanical strength according to the use environment typified by in-vehicle applications, metals such as tungsten (W) and molybdenum (Mo), Cu- Alloys such as W and Cu—Mo, ceramics such as aluminum nitride (AlN), ceramics / metal composite systems such as Al—silicon carbide (SiC) and Si—SiC, diamond, and the like have been put into practical use. However, both are expensive, and there is a problem that metal insulation is poor in electrical insulation. (Non-Patent Document 2)

  Printed circuit boards having a high contribution to heat dissipation include metal substrates, ceramic substrates, and organic substrates, but none of them satisfy all of the characteristics, workability, cost, and the like. (Non Patent Literature 3)

The metal substrate is formed by bonding a copper foil or the like to form a circuit with a copper plate or an aluminum plate via an insulating layer, but since the insulating layer is mainly composed of a polymer compound, the thermal conductivity is poor, There is a problem that the thermal expansion coefficient is large. This problem is caused by introducing a skeleton structure having liquid crystal properties into a polymer compound and orienting it to enhance the thermal conductivity, or by conventional aluminum oxide (Al ₂ O ₃ ), boron nitride (BN), magnesium oxide. (MgO), magnesium hydroxide (Mg (OH) ₂ ), low thermal conductive fillers such as silica (SiO ₂ ) are replaced with high thermal conductive fillers such as AlN particles, and a method for solving this has been studied. There is a possibility that the above problem can be solved by using both. However, the production equipment and production process for aligning the liquid crystal polymer are complicated, and since AlN particles are used, there is a problem that it is very expensive.

For ceramic substrates, copper-clad ceramics with AlN, which has a thermal conductivity similar to that of copper and has a thermal expansion coefficient closer to that of semiconductors than metals such as copper, are laminated directly or via an active metal layer on a copper plate or aluminum plate. A substrate or an aluminum-clad ceramic substrate solves the problem in characteristics and contributes to the improvement of the performance of the semiconductor device (Non-patent Documents 4 and 5). Furthermore, by improving the sintering method, it is possible to obtain silicon nitride (Si ₃ N ₄ ) having less impurity oxygen and grain boundary phase, which has been an adverse effect on thermal conductivity, and has better thermal conductivity and mechanical strength than AlN. A copper-clad substrate using Si ₃ N ₄ has also been developed (Non-patent Document 6). However, in addition to using expensive materials such as AlN particles and Si ₃ N ₄ particles, there is a problem that the workability of ceramics is poor and the material cost and processing cost are extremely high.

  The organic substrate is a composite material obtained by impregnating a reinforcing material such as a glass cloth with a phenol resin, a polyester resin, an epoxy resin, a polyimide resin, a fluororesin, or a film as it is, directly on a copper foil or the like forming a circuit, or It is bonded together via an adhesive layer, has excellent processability and is inexpensive. However, like the insulating layer of the metal substrate, there is a problem that the thermal conductivity is poor and the coefficient of thermal expansion is large, and basically the same measures as the insulating layer of the metal substrate are considered. Therefore, like the metal substrate, there are problems in process and price.

  In addition, heat dissipation sheets and encapsulants that efficiently conduct heat generated in semiconductor elements to heat sinks and heat spreaders are basically similar to the insulating layers of metal substrates and organic substrates as described above. A solution to the exact same problem is taken and a similar problem arises.

As described above, no material that solves all the problems of heat generation of semiconductor devices has been found. However, AlN particles and Si ₃ N ₄ particles can be used as a sintered body in heat sinks, heat spreaders, and printed circuit boards. Moreover, since it can utilize also as a filler for a printed circuit board, a heat dissipation sheet, and a sealing material, conventionally, aluminum oxide (Al ₂ O ₃ ), boron nitride (BN), and hydroxide used as heat conductive fillers are used. As a material that can realize thermal conductivity that cannot be achieved with magnesium (Mg (OH) ₂ ), magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), calcium carbonate (CaCO ₃ ), silica (SiO ₂ ), etc. (Patent Document 1). Therefore, even if the Al ₂ O ₃ reduction nitriding method requires a long time treatment at a high temperature of 1,500 ° C. or higher, it consumes less energy than the reduction nitriding method, but the direct nitriding method requires a forced pulverization step. Various improvements have also been made (Patent Documents 2, 3, 4, and 5). Conventionally, it was molded by sintering at a temperature close to 2,000 ° C. for several tens to several hundred hours, but a mild sintering method using millimeter waves has also been proposed (Patent Document 6). . However, in the case of the production of the particles, a high temperature of about 1,000 ± 400 ° C. is required, and in the case of the production of the sintered body, a temperature of 1,500 ° C. or more is required for several hours, However, the problem of manufacturing price cannot be improved very much.

  On the other hand, a method has also been proposed in which an AlN film excellent in electrical insulation is coated with tungsten or molybdenum having a low thermal expansion coefficient but poor electrical insulation by chemical vapor deposition (CVD) (Patent Document 7). ). However, in addition to film forming conditions close to 1,000 ° C., heat treatment conditions exceeding 1,000 ° C. are necessary, and it is difficult to overcome the manufacturing price as in the case of the above particles.

JP 2009-286668 A International Publication No. 2012/077551 International Publication No. 2013/146894 JP 2008-007357 A International Publication No. 2013/146713 JP 2003-321275 A JP 2011-225909 A JP2012-057198A International Publication No. 2012/150804

(Company) Hybrid Microelectronics Association, "Electronics Packaging Technology Basic Course, Volume 6, Design / Reliability Evaluation Technology", January 1995. (Company) Hybrid Microelectronics Association, "Electronic Packaging Technology Basic Course, Volume 2, Mounting Board", January 1995. Daizo Baba et al., Panasonic Electric Works Technical Report, “Technological Trends of High Heat Dissipation Substrate Materials”, Vol. 59, no. 1, p. 17. Ceramics Archives, “Aluminum Nitride Substrate for Semiconductor Devices”, Ceramics 41 (2006) No. 12, p. 1044. Goto Ikuo et al., "Directional solidification control in AlN substrate-integrated pure Al base joint casting for power modules", Journal of the Japan Welding Society, Vol. 30, No. 4, p. 345 (2012). Hirao Kiyoji et al., “Silicon nitride ceramics with high thermal conductivity”, AIST TODAY, 2012-02, p. 16. W. Ensinger et al. , "Surface treatment of aluminum oxide and tungusten carbide powders by ion beam sputter deposition", Surface and Coatings Technology, 163-164. 281-285. Yasunori Taga, “Research on Thin Film Process Technology”, Integrated Engineering, Vol. 22 (2010) 53-64. Nobuyuki Toyoda et al., “Trends and Prospects of Nanotechnology”, Toshiba Review, vol. 57, no. 1 (2002) p. 2-8.

In view of the above problems, the present invention is capable of manufacturing a heat dissipation structure for a semiconductor device at a low cost, and is coated with AlN or Si ₃ N ₄ having high thermal conductivity, high electrical insulation, and low thermal expansion. An object of the present invention is to provide a heat dissipation structure such as a heat sink, a heat spreader, a printed circuit board, a heat dissipation sheet, and a sealing material using the powder. In addition, an object of the present invention is to provide a method for producing the above powder suitable for a heat dissipation structure.

The present invention relates to an AlN or Si ₃ N ₄ coated powder produced by depositing Al or Si nanoparticles on the surface of an inorganic particle and then heat-treating in a nitrogen (N ₂ ) atmosphere. As a result of being applied to heat dissipation structures, such as heat sinks, heat spreaders, printed circuit boards, heat dissipation sheets, and sealing materials, it has low thermal expansion in addition to excellent thermal conductivity and high electrical insulation It is found that it becomes a heat dissipation structure, and in particular, it is produced by depositing Al or Si nanoparticles on agitated inorganic particles by physical vapor deposition (PVD) method and then heat-treating them under N ₂ atmosphere. It has been found that powder coated with AlN or Si ₃ N ₄ is excellent as a material for a heat dissipation structure constituting the semiconductor device, and the present invention has been completed. That is, the present invention provides a powder coated with AlN or Si ₃ N ₄ having high thermal conductivity, high electrical insulation, and low thermal expansion, and a heat dissipation structure suitable for a semiconductor device using the same. It is to provide. The present invention also provides a method for producing the powder.

More specifically, the present invention provides a PVD tank with an evaporation source provided in the upper part thereof, an agitation tank in which a base material on which an evaporated substance is provided provided in the lower part of the evaporation source is charged, and the stirring tank. At least a stirrer for uniformly depositing the provided evaporation substance on the base material is installed, and as the base material, inorganic particles are introduced into the stirring layer, while the inorganic particles are stirred using Al or Si as an evaporation source In addition, Al nanoparticles or Si nanoparticles having a particle diameter of 1 to 50 nm are deposited on the surface so as to have a predetermined thickness, and then heat-treated at 400 to 600 ° C. for 3 to 6 hours in an N ₂ atmosphere. A powder coated with AlN or Si ₃ N ₄ having both high thermal conductivity, high electrical insulation, and low thermal expansion, and a heat dissipation structure suitable for a semiconductor device using the powder That provides the body is there. And, the present invention is to provide the method of producing a powder coated with AlN or Si ₃ N _4.

The inorganic particle is not particularly limited as long as it is a material that can withstand heat treatment after Al nanoparticles or Si nanoparticles are deposited, but is inexpensive, Al ₂ O ₃ , Mg (OH) ₂ , MgO MgCO ₃ , CaCO ₃ , SiO ₂ or the like is preferably used.

  Since the present invention uses Al nanoparticles or Si nanoparticles having a particle diameter of 1 to 50 nm, the size effect allows nitriding under milder conditions than conventional processing conditions. In addition, since the inorganic particles are covered with inexpensive inorganic particles, the cost is much lower than when using conventional powders such as AlN, SiN, silicon carbide (SiC), and BN.

  The powder of the present invention can be sintered under conditions that are much milder than conventional sintering conditions, and the sintered body has low thermal expansion in addition to excellent thermal conductivity and high electrical insulation. Molded bodies such as heat sinks, heat spreaders, and ceramic printed circuit boards can be provided at low cost. Moreover, if it uses as fillers, such as an organic printed circuit board, a thermal radiation sheet, a sealing material, various insulating materials, and an adhesive agent, the organic thermal radiation structure excellent in thermal conductivity can be provided at low cost.

As described above, the powder of the present invention is inexpensive and exhibits excellent effects as the sintered body and the organic heat dissipation structure, as shown in FIG. 12 is presumed to be due to the formation of a core-shell structure covered with the shell 11 of AlN nanoparticles or Si ₃ N ₄ nanoparticles. First, based on this structure, the conditions for molding the sintered body are mild due to the nanoparticle effect. Furthermore, as shown in FIG. 2 (b), the manufactured sintered body has inorganic particles in the sea 11 made of AlN or SiN having excellent thermal conductivity, electrical insulation, and thermal expansion. The sea-island structure existing as No. 12 is formed, and the sintered body exhibits the characteristics of the sea strongly. When the powder of the present invention is used as a filler, as shown in FIG. 2 (c), if only the shell layer 11 is in contact, the thermal conductivity, electrical insulation, and thermal expansion of AlN or SiN. Therefore, an inexpensive organic heat dissipation structure that does not impair the characteristics of the resin 14 can be obtained.

Furthermore, according to the method for producing nanoparticles using the PVD method of the present invention, highly pure AlN or Si ₃ N ₄ is produced with very little impurities such as oxygen, and AlN or Si having high thermal conductivity. _Since powder coated with ₃ N ₄ can be manufactured, AlN or Si ₃ N _{4 having} high thermal conductivity, high electrical insulation, and low thermal expansion suitable for manufacturing a heat dissipation structure suitable for a semiconductor device A powder coated with can be provided.

It is sectional drawing which shows the heat dissipation path | route of FBGA (Fine Pitch Ball Grid Array) semiconductor package board | substrates. (A) It is a conceptual diagram of a sea-island structure and a heat conduction path when used as a sintered body for a ceramic printed circuit board. (B) It is a conceptual diagram of a sea-island structure and a conduction path when used as a filler of an insulating material of an organic printed circuit board. It is a schematic diagram of the PVD apparatus which manufactures the inorganic particle which deposited Al or Si nanoparticle.

The powder coated with AlN or Si ₃ N ₄ of the present invention is obtained by depositing Al nanoparticles or Si nanoparticles having a particle diameter of 1 to 50 nm deposited on inorganic particles at 400 to 600 ° C., 3 to 3 in an N ₂ atmosphere. Heat-treated for 6 hours.

In the present invention, the average particle diameter of the inorganic particles is preferably 0.05 to 100 μm, more preferably 0.1 to 50 μm, and still more preferably 1 to 25 μm. It is not particularly limited as long as it does not decompose or change under the heat treatment conditions, but Al ₂ O ₃ , Mg (OH) ₂ , which has been used as a filler for various composite materials such as printed circuit boards, MgO, MgCO ₃ , CaCO ₃ , and SiO ₂ are preferable because they have stable physical properties and are inexpensive. In particular, Al ₂ O ₃ is preferably used. The shape is preferably rounded, and more preferably spherical. The average particle diameter is preferably 1 to 75 μm, and more preferably 1 to 25 μm. Examples of such spherical Al ₂ O ₃ include Aruna beads (registered trademark) manufactured by Showa Denko KK and Denka spherical alumina manufactured by Denki Kagaku Kogyo.

  As Al nanoparticles or Si nanoparticles to be deposited on the inorganic particles, a vapor phase method, a liquid phase method, or any other method can be used. However, in order to fix a predetermined amount of nanoparticles to the inorganic particle surface and reduce impurities with respect to the inorganic particle, the inorganic particle is agitated using Al or Si as an evaporation source in a general PVD apparatus. However, it is preferable to deposit Al particles or Si particles on the surface of the inorganic particles by the PVD method. The particle diameter of the nanoparticles is preferably 1 to 50 nm, more preferably 1 to 25 nm, and still more preferably 1 to 10 nm. The amount of the nanoparticles deposited corresponds to the particle diameter of the inorganic particles, and is preferably 0.05 to 100 μm, 0.1 to 50 μm, and 1 to 25 μm, respectively.

  As shown in FIG. 3, the specific manufacturing method of the present invention is an agitation in which an evaporation source 16 provided in the upper part of the PVD tank 15 and a base material on which the evaporated substance provided in the lower part of the evaporation source is deposited. By installing at least a stirrer 18 for uniformly depositing the evaporation substance provided in the tank 17 and the stirring tank on the base material, and evaporating the metal of the evaporation source 16 while stirring the base material, metal nanoparticles are obtained. Is deposited on the surface of the base material. As the PVD method, a vacuum deposition method, an ion beam deposition method, an ion plating method, and various sputtering methods can be used. For example, methods such as Non-Patent Document 7, Patent Documents 8 and 9 are disclosed. . The particles carrying the metal nanoparticles thus produced are preferably stored in a container substituted with an inert gas because the subsequent nitridation is hindered by the surface oxidation of the metal nanoparticles.

  In the above manufacturing method, the mechanism by which the nanoparticles are generated on the base material is not clear, but is estimated as follows. It is said that there are three types of film deposition mechanisms such as general vapor deposition and sputtering, Volmer-Weber (VW) growth, Frank-van der Merwe (FM) growth, and Stranski-Krastanov (SK) growth (non-). Patent Document 8). Among them, the VW growth mode, that is, three-dimensional island-like nuclei are formed from the initial stage of growth, and they grow together with an increase in the amount of deposition, and eventually merge into a continuous film. Focusing on the “Growth” style, there are differences in the film formation mechanism depending on various parameters such as surface energy and temperature related to the physical vapor deposition material and the substrate, but the conditions for VW growth are found in the initial stage of film formation, and the base material is stirred. However, if physical vapor deposition is performed, a new deposition surface is always directed to the vapor deposition material, and it is considered that a three-dimensional sea-island structure, that is, nanoparticles are generated one after another.

As a result of various studies, it has been found that the powder of inorganic particles coated with Al nanoparticles or Si nanoparticles is nitrided under mild heat treatment conditions that could not be achieved by the prior art. That is, in _{an N 2} atmosphere, 400 to 600 ° C., 3 to 6 hours, more preferably, in the _{N 2} atmosphere at a pressure above 100～200KPa, is nitrided by 450 to 550 ° C., held for 4-5 hours . This is presumably because the nanoparticle has a very large surface area compared to its volume, and therefore changes in mechanical, thermal, or catalytic properties (Non-Patent Document 9).

The powder coated with AlN or Si ₃ N ₄ thus produced can be widely used as a raw material for sintering, filler, etc. as a material having high thermal conductivity, electrical insulation and low thermal expansion.

  First, when producing a sintered body suitable for a heat dissipation structure constituting a semiconductor device, for example, a heat sink, a heat spreader, and a printed circuit board, as a sintering raw material, even with a general sintering method, the sintering is performed under sufficiently mild conditions. I can conclude. As sintering aids, select rare earth oxides, carbides, halides (eg fluorides), titanium oxide, zirconium oxide, lithium oxide, boron oxide, calcium oxide, etc. alone or in combination. used. The sintering method is mainly an atmospheric pressure sintering method that is excellent in operability and adaptable to complex shapes, pressure sintering that can reduce the amount of sintering aid added, and obtain a compact sintered body Can be used. In particular, as a pressure sintering method, a hot press (up to 50 MPa) that simultaneously performs gas pressure sintering, molding and sintering by increasing the gas pressure (0.2 to 10 MPa) of the atmosphere and suppressing decomposition of the raw material powder. Is preferably used. Such sintering generally requires a temperature of about 2,000 ° C. in any method, but if the powder of the present invention is used, it can be sintered at a temperature lower by 500 ° C. or more. Furthermore, the strength can be further improved by subjecting the obtained sintered body to hot isostatic pressing (HIP). The HIP treatment is usually performed in an inert gas atmosphere at a pressure of 30 to 300 MPa and a sintering temperature of 2100 to 2200 ° C. In addition, the thermal plasma sintering method, which is pressureless sintering using ultra-high temperature plasma heat, and the discharge plasma sintering method, which uses spark discharge energy to sinter under pressure, can be rapidly heated, and can be done in a short time. A method capable of sintering can also be used.

On the other hand, an organic heat dissipation structure in which powder coated with AlN or Si ₃ N ₄ of the present invention is dispersed in a polymer compound, for example, an organic printed circuit board, a heat dissipation sheet, a sealing material, various insulating materials / adhesives, etc. Also when used for, it can be used in the same manner as conventional fillers. Although typical production methods are described below, various production methods can be used depending on the application, configuration, performance, and the like, and the present invention is not limited thereto.

  For example, in the case of an organic printed circuit board, a solution containing at least one resin such as a phenol resin, a polyester resin, an epoxy resin, a polyimide resin, a fluororesin, a silicon resin, or the like that forms the skeleton of a heat dissipation structure or a dispersant is used. A masterbatch prepared by adding the powder of the invention and dispersing by a general method such as a ball mill, a sand mill, or a roll mill is mixed with a solution in which the phenol resin, polyester resin, epoxy resin, polyimide resin, or the like is dissolved. This mixed solution contains a curing catalyst as necessary, and can be a one-component curing type or a two-component curing type. This mixed solution is produced by impregnating a reinforcing material such as glass cloth, and directly adhering to a copper foil or the like forming a circuit, followed by drying and curing. In some cases, the film is once dried and cured, and then bonded to a copper foil or the like forming a circuit via an adhesive layer. Furthermore, a film-based organic printed circuit board can also be produced without using a reinforcing material such as glass cloth.

  Moreover, in the case of a heat-radiation sheet, various insulating materials, adhesives, etc., it is obtained by coating and drying the mixed solution as it is, and the sealing solution uses the mixed solution as it is.

  Depending on the application, the selected resin, curing method, and the like are different, and a solventless system may be selected depending on workability, environmental compatibility, and the like.

  Hereinafter, although a concrete example is given and the present invention is explained more concretely, the technical idea of the present invention is not restricted by the example.

First, an appropriate amount of spherical Al ₂ O ₃ (Arnabeads CB-P05, Showa Denko) having an average particle diameter of about 4 μm is charged into a stirring tank 17 provided in the vacuum deposition tank 15 shown in FIG. . Next, the deposition source 16 is provided with an Al wire for vacuum deposition (manufactured by ULVAC TECHNO). This Al wire has a purity of 99.0 to 99.999%.

Next, Ar is introduced into the vacuum deposition tank 15 from the inert gas introduction system 21 while evacuating the vacuum deposition tank so that the degree of vacuum is 1 × 10 ⁻⁴ to 1 torr. When the degree of vacuum is stable, the silicon of the vapor deposition source 16 is evaporated at a rate of 1 to 10 μm / min per unit area on a fixed flat substrate while stirring the propeller 18 of the stirring tank 17 at a rotational speed of 1 to 200 rpm. Then, the shutter 20 was opened, and Al nanoparticles of 1 to 10 nm were formed on the Al ₂ O ₃ surface. When the thickness of the Al nanoparticles reaches 1μ, the shutter 20 is closed. The Al ₂ O ₃ powder on which the generated Al nanoparticles were deposited was stored in a nitrogen-substituted container in order to prevent oxidation.

The Al ₂ O ₃ powder supported on the Al nanoparticles can be nitrided almost completely by holding it at 110 ° C. in an N ₂ atmosphere at 500 ° C. for 4 hours to obtain an Al ₂ O ₃ powder coated with AlN. It was.

Using the AlN-coated Al ₂ O ₃ powder thus produced, a heat spreader was produced by a hot press furnace (PHP manufactured by Shimadzu Mektem). The hot press conditions were a pressure of 5 MPa and a sintering temperature of 1,500 ° C. in an N ₂ atmosphere. This heat spreader was 200 W / m · K, showed thermal conductivity substantially equivalent to that of an AlN carrier, was electrically insulating, and had a thermal expansion coefficient close to that of a Si semiconductor of 5.5 ppm / K.

54 parts by weight of a biphenyl type epoxy resin (YX7399, manufactured by Mitsubishi Chemical Corporation), 45 parts by weight of a phenol resin (Millex (registered trademark) RN-2830MB (containing hexamethylenetetramine), manufactured by Mitsui Chemicals), a silane coupling agent (KBM403, (Shin-Etsu Chemical Co., Ltd.) 1 part by weight silane coupling agent (KBM403, Shin-Etsu Chemical Co., Ltd.) 1 part by weight, AlN-coated Al ₂ O ₃ powder 800 parts by weight of the present invention, and after mixing uniformly with a stirrer, The mixture was kneaded with three rolls heated to 95 to 105 ° C. to prepare an epoxy resin-based basic composition suitable for a sealing material. This was heat-cured at 160 ° C. for 1 hour to produce a physical property measurement sheet. As a result, it was 150 W / m · K, showed thermal conductivity close to that of an AlN carrier, was electrically insulating, and had a thermal expansion coefficient close to that of a Si semiconductor of 7 ppm / K.

DESCRIPTION OF SYMBOLS 1 Thermal conduction path | route 2 Thermal convection path | route 3 Thermal radiation path | route 4 Heat spreader 5 Adhesive 6 Semiconductor chip 7 Sealing material 8 Solder ball 9 Build-up board 10 Mother board 11 AlN or Si ₃ N ₄
12 Inorganic particles 13 Copper or aluminum plate 14 Synthetic resin 15 Vacuum deposition tank 16 Deposition source 17 Stirring tank 18 Propeller 19 Motor 20 Shutter 21 Gas introduction system 22 Vacuum exhaust system

Further, specifically, the present invention is, in PVD chamber, the evaporation source provided thereon, stirred tank for introducing base material in which the evaporation source evaporating material provided in the lower is deposited, in that 撹拌槽at least placed 撹 agitator, for evaporating material provided is uniformly deposited on the base material, as a base material, was charged inorganic particles 撹拌層as evaporation sources of Al and Si, the inorganic particles The Al nanoparticles or Si nanoparticles having a particle diameter of 1 to 50 nm are deposited on the surface so as to have a predetermined thickness, and then heat-treated in an N ₂ atmosphere at 400 to 600 ° C. for 3 to 6 hours. A powder coated with AlN or Si ₃ N ₄ having high thermal conductivity, high electrical insulation, and low thermal expansion, and a semiconductor device using the powder To provide a suitable heat dissipation structure is there. And, the present invention is to provide the method of producing a powder coated with AlN or Si ₃ N _4.

Since the present invention uses Al nanoparticles or Si nanoparticles having a particle diameter of 1 to 50 nm, the size effect allows nitriding under milder conditions than conventional processing conditions. In addition, since the inorganic particles are covered with inexpensive inorganic particles, the cost is much lower than when using conventional powders such as AlN, Si ₃ N ₄ , silicon carbide (SiC), and BN.

As described above, the powder of the present invention is inexpensive and exhibits excellent effects as the sintered body and the organic heat dissipation structure, as shown in FIG. 12 is presumed to be due to the formation of a core-shell structure covered with the shell 11 of AlN nanoparticles or Si ₃ N ₄ nanoparticles. First, based on this structure, the conditions for molding the sintered body are mild due to the nanoparticle effect. Further, as shown in FIG. 2B, the manufactured sintered body is inorganic in the sea 11 made of AlN or Si ₃ N ₄ excellent in thermal conductivity, electrical insulation, and thermal expansion. A sea-island structure in which particles exist as islands 12 is formed, and a sintered body that strongly expresses the characteristics of the sea is obtained. Further, when the powder of the present invention is used as a filler, as shown in FIG. 2 (c), if only the shell layer 11 is in contact, the thermal conductivity, electrical insulation, and electrical properties of AlN or Si ₃ N ₄ In addition, since it exhibits thermal expansibility, an inexpensive organic heat dissipation structure that does not impair the characteristics of the resin 14 can be obtained with a small amount of addition.

As shown in FIG. 3, the specific manufacturing method of the present invention is an agitation in which an evaporation source 16 provided in the upper part of the PVD tank 15 and a base material on which the evaporated substance provided in the lower part of the evaporation source is deposited. bath 17, at least placed 撹 agitator 18 for evaporating material provided in 撹拌槽is uniformly deposited on the base material, while stirring the base material by evaporating the metal evaporation source 16, Metal nanoparticles are deposited on the matrix surface. As the PVD method, a vacuum deposition method, an ion beam deposition method, an ion plating method, and various sputtering methods can be used. For example, methods such as Non-Patent Document 7, Patent Documents 8 and 9 are disclosed. . The particles carrying the metal nanoparticles thus produced are preferably stored in a container substituted with an inert gas because the subsequent nitridation is hindered by the surface oxidation of the metal nanoparticles.

54 parts by weight of a biphenyl type epoxy resin (YX7399, manufactured by Mitsubishi Chemical Corporation), 45 parts by weight of a phenol resin (Millex (registered trademark) RN-2830MB (containing hexamethylenetetramine), manufactured by Mitsui Chemicals), a silane coupling agent (KBM403, Shin-Etsu chemical Co., Ltd.) 1 part by weight of silane coupling agent (KBM403, Shin-Etsu chemical Co., Ltd.) 1 part by weight, AlN coated _Al 2 _{O 3} powder 800 parts by weight of the present invention, the blended and uniformly mixed in 撹 agitator Then, it knead | mixed with the three rolls heated at 95-105 degreeC, and prepared the epoxy resin type | system | group basic composition suitable for a sealing material. This was heat-cured at 160 ° C. for 1 hour to produce a physical property measurement sheet. As a result, it was 150 W / m · K, showed thermal conductivity close to that of an AlN carrier, was electrically insulating, and had a thermal expansion coefficient close to that of a Si semiconductor of 7 ppm / K.

Claims (5)

  1. A powder coated with AlN or SiN and a heat dissipation structure using the powder, wherein Al or Si nanoparticles are deposited on the surface of inorganic particles and then heat-treated in a nitrogen atmosphere. The inorganic particles are Al ₂ O ₃ , Mg (OH) ₂ , MgO, MgCO ₃ , CaCO ₃ , SiO ₂ having an average particle diameter of 0.1 to 100 μm, and the nanoparticles have an average particle diameter of 0.1 to 100 μm. 2. The powder coated with AlN or SiN according to claim 1, wherein the powder is deposited at a thickness of 100 to 100 μm on the inorganic particles at a thickness of 0.1 to 100 μm and then heat-treated in a nitrogen atmosphere. Heat dissipation structure using The inorganic particles are spherical Al ₂ O ₃ having an average particle diameter of 1 to 75 μm, and after the nanoparticles are deposited with a thickness of 1 to 75 μm, heat treatment is performed in a nitrogen atmosphere. A powder coated with the described AlN or SiN and a heat dissipation structure using the powder.   4. The powder coated with AlN or SiN and the powder according to claim 1, wherein the heat treatment is performed in a nitrogen atmosphere at 400 to 600 ° C. for 3 to 6 hours. Heat dissipation structure.   An Al or Si evaporation source provided in the upper part of the physical vapor deposition tank, an agitation tank into which the inorganic particles deposited on the evaporation substance provided in the lower part of the evaporation source are charged, and the evaporation substance provided in the stirring tank At least a stirrer for uniformly depositing the inorganic particles was installed, and the Al or Si nanoparticles were deposited on the surface of the inorganic particles by evaporating the Al or Si evaporation source while stirring the inorganic particles. A method for producing a powder coated with AlN or SiN, which is then heat-treated in a nitrogen atmosphere.

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