JP2018032711A - Heat sink manufacturing method - Google Patents

Abstract

A heat sink manufacturing method that does not require a mold for forming a heat-dissipating coating layer is provided. A casting process for forming a base material by casting (steps S1 to S5), and a heat-dissipating paint is included in the base material C while residual heat in the casting process remains on at least the surface of the base material C. A film forming step (step S6) of spraying the paint-containing fiber T in a thread shape to form a heat-dissipating layer on the surface of the substrate C. [Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a heat sink.

  In recent years, with the miniaturization of electric circuits in semiconductor devices and the like, the heat generation density of the electric circuits has increased. Therefore, it is important to improve the heat dissipation performance of the electric circuit in the semiconductor device. The heat sink (casing) of a unit having a high heat generation density is generally formed of a metal such as aluminum having a high thermal conductivity. However, although the metal such as aluminum has a high thermal conductivity, the thermal conductivity from the metal to the air tends to be low. For this reason, it has been proposed to form a material such as carbon, nitride, or resin having a higher thermal conductivity to the air than metal on the surface of the metal heat dissipation component.

  In Patent Document 1, a base material of a heat dissipation base is formed by a die casting method, and a heat-dissipating coating layer is fired by resin injection molding on the surface of the base material in a high temperature state immediately after the base material is formed. A base manufacturing method is described.

JP-A-57-202683

  However, in the method described in Patent Document 1, it is necessary to prepare a mold for injection molding for injection molding of a heat-dissipating coating layer in addition to a mold for molding a heat sink base material. In addition, there is a problem that the molds must be prepared individually according to changes in the shape and dimensions of the heat sink and variations.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide a method for manufacturing a heat sink that does not require a mold for forming a heat-dissipating coating layer. is there.

  The method of manufacturing a heat sink according to the present invention includes a casting step of forming a base material by casting, and a fiber containing a heat-dissipating paint is sprayed in a thread shape on the base material where at least the residual heat in the casting step remains on the surface. A film forming step of forming a heat dissipating layer on the surface of the substrate.

  According to the heat sink manufacturing method of the present invention, a heat-dissipating layer is formed on the surface of the base material by spraying fibers containing heat-dissipating paint on the base material where at least the residual heat in the casting process remains on the surface. A film can be formed. Specifically, when a fiber containing a heat dissipating paint is sprayed on the surface of the base material, the heat dissipating paint can be baked on the surface of the base material by the residual heat in the casting process. Thereby, the manufacturing method of a heat sink which does not require the metal mold | die for shape | molding the heat-radiation film layer can be provided.

It is a figure explaining the manufacturing method of the heat sink which concerns on Embodiment 1 of this invention. It is a figure which shows schematic structure of the coating material containing fiber spraying apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the manufacturing method of the conventional heat sink.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a method of manufacturing a heat sink according to the first embodiment.
As shown in FIG. 1, in the heat sink manufacturing method according to the first embodiment, first, a release agent is applied to the wall surface of the cavity of the molding die (step S1).

  Next, the mold is closed and the molten metal is injected and injected into the mold through the injection hole (step S2). When the molten metal is molten aluminum, the temperature of the molten metal is about 700 ° C.

  Next, the molten metal is solidified in the molding die (step S3).

  Next, the mold is opened (step S4), and the base material (coarse material) C is taken out of the mold (step S5).

  Next, using the paint-containing fiber spraying apparatus 100 according to Embodiment 1 of the present invention, a fiber containing a heat-radiating paint on the base material C where at least the residual heat in the casting process of Steps S1 to S5 remains on the surface. (Hereinafter, referred to as “paint-containing fiber”) is sprayed in a thread shape, and the paint-containing fiber is fired on the surface of the substrate C by the residual heat (step S6: film forming step). Thereby, a heat dissipation layer is formed on the surface of the substrate C, and a heat sink is manufactured.

  In FIG. 2, schematic structure of the paint containing fiber spraying apparatus 100 which concerns on Embodiment 1 is shown. As shown in FIG. 2, the paint-containing fiber spraying device 100 according to the first embodiment includes a resin tank 1, a bobbin 2, a drawing roller 3, a nozzle 4, an air supply device 5, a control device 6, and the like.

  The resin tank 1 stores a heat dissipating coating material including a thermoplastic resin, a thermosetting resin, and the like. Examples of the thermoplastic resin include polyamideimide (PAI). Examples of the thermosetting resin include epoxy paints and phenol paints.

  The bobbin 2 is wound with a thread material (hereinafter simply referred to as “fiber”) T made of a fiber that can be infiltrated with a heat dissipating paint. Further, the bobbin 2 is immersed in a heat dissipating paint stored in the resin tank 1. Thereby, the heat dissipating paint infiltrates into the transition T, and the fiber T contains the heat dissipating paint. In addition, as the fiber T, it is preferable to use a reinforcing fiber in order to improve the strength of the heat dissipation layer formed on the heat sink. Examples of reinforcing fibers include carbon fibers and glass fibers.

  The drawing roller 3 is rotatably supported by the paint-containing fiber spraying device 100 and draws out a fiber (paint-containing fiber) T containing a heat dissipating paint from the bobbin 2.

The nozzle 4 injects the paint-containing fiber T drawn by the drawing roller 3 toward the surface of the substrate C. Specifically, the paint-containing fiber T is sprayed toward the surface of the substrate C together with the air supplied from the air supply device 5 to the nozzle 4.
The nozzle 4 is supported by a table or the like so that the nozzle 4 can be translated and rotated.

  The air supply device 5 supplies the nozzle 4 with air for injecting the paint-containing fiber T.

The control device 6 includes a CPU (not shown) and a storage unit (not shown). And all the processes in the control apparatus 6 are implement | achieved when CPU runs the program stored in the memory | storage part.
Moreover, the program stored in each memory | storage part of the control apparatus 6 contains the code for implement | achieving the process in each of the control apparatus 6 by being performed by CPU. The storage unit includes, for example, an arbitrary storage device that can store this program and various types of information used for processing in the control device 6. The storage device is, for example, a memory.

  Specifically, when the CPU executes a program stored in the storage unit, the control device 6 controls each unit of the paint-containing fiber spraying device 100. More specifically, when the CPU executes a program stored in the storage unit, the control device 6 inputs a command for the direction of the nozzle 4 to a table or the like that supports the nozzle 4, for example. The direction in which the paint-containing fiber T is jetted is controlled. Further, when the CPU executes a program stored in the storage unit, the control device 6 is jetted from the nozzle 4 by controlling the flow rate and flow velocity of the air supplied from the air supply device 5 to the nozzle 4. The flight distance of the paint-containing fiber T is controlled.

  In step S6, using the paint-containing fiber spraying device 100, the paint-containing fibers T are sprayed in the form of threads on the base material C where at least the residual heat in the casting process remains on the surface. The contained fiber T is fired.

Specifically, in step S6, while the surface temperature of the base material C is equal to or higher than the film forming temperature of the heat dissipating paint, the paint-containing fiber T is applied to the base material C using the paint-containing fiber spraying device 100. Spray in a string.
Here, the film formation temperature of a thermoplastic resin such as polyamideimide (PAI) is, for example, a temperature at which a solvent that dissolves polyamideimide as a solute evaporates and the polyamideimide is softened by its plasticity. Moreover, the film-forming temperature of thermosetting resins, such as an epoxy-type coating material and a phenol-type coating material, is a curing temperature of a thermosetting resin.
When the heat dissipating coating material is polyamideimide (PAI), the coating material-containing fiber T is sprayed onto the base material C while the surface temperature of the base material C is about 180 ° C. or more, which is the film formation temperature of the polyamideimide. Further, when the heat dissipating paint is an epoxy paint or a phenol paint, the surface temperature of the substrate C is about 170 ° C. or more, which is the film forming temperature (curing temperature) of the epoxy paint or the phenol paint. The paint-containing fiber T is sprayed on the base material C.

  When the molten metal is a molten aluminum, the temperature of the molten metal is about 700 ° C., and thus the surface temperature of the base material C immediately after molding is equal to or higher than the film forming temperature of the heat dissipating paint. And the surface temperature of the base material C taken out from the molding die in step S5 falls as time passes. Therefore, while the surface temperature of the base material C taken out from the molding die is equal to or higher than the film forming temperature of the heat dissipating paint applied to the base material C, the paint-containing fiber T is sprayed onto the base material C. Further, the setting is such that the surface temperature of the base material C taken out from the molding die is equal to or higher than the film forming temperature of the heat dissipating paint applied to the base material C, and is set higher than the film forming temperature by a predetermined temperature. While the temperature is lower than the temperature (for example, a temperature obtained by adding 100 ° C. to the film formation temperature), it is preferable to spray the coating material-containing fiber T onto the base material C. Thereby, the coating material of the coating-containing fiber T is baked on the surface of the base material C, a heat-radiating layer is formed on the surface of the base material C, and a heat sink is manufactured.

  According to the heat sink manufacturing method according to the first embodiment described above, the paint-containing fiber T is sprayed in a thread form on the base material C where at least the residual heat in the casting process of steps S1 to S5 remains on the surface, A heat dissipation layer can be formed on the surface of the substrate C. Specifically, when the paint-containing fiber T is sprayed on the surface of the base material C, the paint of the paint-containing fiber T can be baked on the surface of the base material C by the residual heat in the casting process. Thereby, the manufacturing method of a heat sink which does not require the metal mold | die for shape | molding the heat-radiation film layer can be provided.

  Moreover, according to the manufacturing method of the heat sink which concerns on this Embodiment 1, since the metal mold | die for shape | molding a heat-radiation film layer is not required, the freedom degree of the shape of a heat sink can be made high.

  Moreover, according to the heat sink manufacturing method according to the first embodiment, the strength of the heat-dissipating layer formed on the surface of the base material C is improved by using the reinforcing fiber as the fiber of the paint-containing fiber T. be able to.

  Moreover, compared with the conventional manufacturing method of a heat sink, after apply | coating a coating material to the surface of the base material C, it heats with a furnace and does not need the process of baking a coating material on the surface of the base material C. FIG. 3 shows an example of a conventional heat sink manufacturing method. Steps S101 to S105 in FIG. 3 are the same as steps S1 to S5 in FIG.

  In the conventional heat sink manufacturing method, the base material C taken out from the molding die is conveyed (step S106), the paint is applied to the surface of the base material C (step S107), and then the base material C is put in a furnace. The coating material is baked on the surface of the base material C by heating (step S108). Therefore, the conventional heat sink manufacturing method requires a furnace for heating the substrate C, requires a baking step (step S108), and also requires energy required for heating for baking.

  On the other hand, in the heat sink manufacturing method according to the first embodiment, a furnace for heating the substrate C is not required, the baking process (step S108) is not required, and energy required for heating for baking. It is not necessary. Therefore, the heat sink manufacturing method according to the first embodiment can reduce the manufacturing time of the heat sink and the manufacturing cost as compared with the conventional method.

  Further, the direction in which the paint-containing fiber T is ejected from the nozzle 4 is controlled by the control device 6. The paint-containing fiber T is sprayed on the surface of the base material C in a thread shape. Therefore, a heat-radiating coating layer can be formed at a desired position on the surface of the substrate C with a thread-like spatial resolution. That is, the degree of freedom in forming the heat-dissipating coating layer is high.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the process of step S6 in the heat sink manufacturing method according to the first embodiment is applicable not only to the heat sink but also to the manufacture of products manufactured by applying paint-containing fibers to the substrate surface.

DESCRIPTION OF SYMBOLS 1 Resin tank 2 Bobbin 3 Pull-out roller 4 Nozzle 5 Air supply apparatus 6 Control apparatus 100 Paint containing fiber spraying apparatus C Base material T Paint containing fiber

Claims (1)

A casting process for forming a substrate by casting;
A film forming step of forming a heat dissipating layer on the surface of the substrate by spraying fibers containing a heat dissipating paint on the substrate in which at least the residual heat in the casting process remains on the surface;
A method of manufacturing a heat sink.

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