JP2006322665A - Hollow laminate, plate type cooling member using it, and electronic apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow laminate using an aluminum sheet which can be joined by low temperature soldering without requiring a large-scale pressure welding device, a plate type cooling member using it, and an electronic apparatus using it. <P>SOLUTION: The hollow laminate is formed by soldering and layering at least two surface treated Al sheets comprised by forming a Zn layer, an Ni layer or an Ni-Zn alloy layer, and an Sn layer in an order from base material side on an Al base material, so as to form a hollow part of a predetermined shape on a layered and adjacent opposing face. A heat pipe operating body is sealed in the hollow part to compose the plate type cooling member, and it is applied in a heat dissipation member or the like of the electronic apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hollow laminate using a surface-treated Al thin plate that can be soldered, a plate-type cooling member using the same, and an electronic device using the same.

  In various electronic devices such as personal computers and game machines, high performance and miniaturization are rapidly progressing. In order to realize high performance and miniaturization, a compact heat radiator that efficiently dissipates heat generated from these various electronic devices is required.

  As such a heatsink, in Patent Document 1, a plurality of aluminum alloy materials are laminated and pressure-bonded, and a small-diameter tunnel meandering on the boundary surface of the lamination is formed by a roll bond method, and a heat pipe working liquid is formed in the tunnel. A plate type heat pipe has been proposed for use in a heat diffusion plate enclosing chlorofluorocarbon 134a and the like. This plate-type heat pipe is formed by laminating two metal plates, hot rolling and joining them, and applying an anti-crimping agent in a predetermined pattern in advance to expand the pattern portion of the boundary surface that has become non-crimped. The meandering tunnel is formed. However, since the metal plates are joined by hot rolling, the deformation of the base metal is large, and not only the tunnel shape cannot be formed with high accuracy, but also the joining strength decreases due to alloying between dissimilar metals on the joining surface, etc. Problems also arise.

  Further, in Patent Document 2, the opposing surfaces of adjacent metal plates of a plurality of metal plates are pre-activated in a vacuum chamber, and an anti-bonding agent is applied to the activated surface in a predetermined pattern. There has been proposed a plate laminate in which a pressure-bonding suppressing portion is formed by abutting and overlapping so as to face each other and performing cold pressure welding. In this plate laminated body, a tunnel-shaped hollow portion is formed in a predetermined pattern by expanding the pressure-bonding suppressing portion, and a heat pipe working body is enclosed in the hollow portion to form a plate-type heat pipe. However, since the metal plate is activated in the vacuum chamber, a large-scale vacuum processing apparatus is required to process a large amount of the large metal plate, and the processing takes time. It is disadvantageous in terms of cost to perform a large amount of processing in a short period of time.

Prior art document information relating to the present application includes the following.
Japanese Patent Laid-Open No. 10-185465 Japanese Patent Application Laid-Open No. 2002-221397

  The present invention provides a hollow laminate using an aluminum thin plate that can be joined by low-temperature soldering without requiring a large pressure welding apparatus, a plate-type cooling member using the same, and an electronic device using the same. With the goal.

The hollow laminated body of the present invention that achieves the above object is a hollow laminated body in which at least two surface-treated Al thin plates are laminated by soldering, and a hollow portion having a predetermined shape is formed on the adjacent opposing surfaces. Body (claim 1),
In the hollow laminate of the above (Claim 1), groove processing is performed on at least one of the surface-treated Al thin plates (Claim 2), and the hollow laminate of the above (Claim 1 or 2) In the body,
The surface-treated Al thin plate is formed by sequentially forming a Zn layer, a Ni layer, and a Sn layer from the Al thin plate side (Claim 3), or the surface-treated Al thin plate is a Zn layer, Ni- A Zn alloy layer and a Sn layer are formed (Claim 4), and in the hollow laminate of the above (Claim 3 or 4), an organic resin layer for improving solderability is formed on the Sn layer. It is characterized in that it is formed (Claim 5), and in the hollow laminate of the above (Claim 5), the organic resin layer is a urethane resin (Claim 6).

The plate-type cooling member of the present invention is characterized in that a heat pipe operating body is enclosed in the hollow portion of any one of the above-described hollow laminates (invention 7).
Furthermore, an electronic apparatus according to the present invention is characterized by using the plate-type cooling member of the above (Claim 7) (Claim 8).

  In the hollow laminated body of the present invention, at least two surface-treated Al thin plates formed by forming a Zn layer, a Ni layer or a Ni—Zn alloy layer, and a Sn layer in this order from the substrate side on an Al thin plate substrate are soldered. Since this is a hollow laminate in which a hollow portion having a predetermined shape is formed on the adjacent opposing surfaces that are laminated, large pressure welding such as a hot rolling device or a vacuum processing device using a conventional clad material is used. It does not require an apparatus and can be manufactured at low cost. Therefore, by enclosing the heat pipe working body in the hollow portion of the hollow laminate of the present invention, the plate type cooling member can be manufactured easily and at low cost, and heat dissipation using the plate type cooling member is possible. Can be manufactured at low cost.

Hereinafter, the present invention will be described in detail. As Al used as the substrate of the surface-treated Al thin plate applied to the hollow laminate of the present invention, a pure Al plate having a thickness of 0.05 to 1 mm and JIS standard 1000 series, 2000 series, 3000 series, 5000 series, 6000 series. Both Al and 7000 series Al alloys can be used. These Al substrates made of pure Al or Al alloy are degreased, then acid-etched, and subsequently smut is removed, followed by Zn substitution plating. In the displacement plating of Zn, after immersion treatment with nitric acid, displacement plating treatment with Zn is performed. The Zn substitution plating treatment may be performed in two steps, a first Zn substitution plating treatment and a second Zn substitution plating treatment. In this case, the water washing process is implemented after the process of each process. The Zn plating layer formed by the first Zn substitution plating treatment and the second Zn substitution plating treatment is slightly dissolved when Ni plating is performed after the substitution plating treatment. It is preferable that it is 5-500 mg / m < ² > in a state, and it is more preferable that it is 30-300 mg / m < ² >. The coating amount is adjusted by appropriately selecting the Zn ion concentration in the treatment liquid and the time of immersion in the treatment liquid in the second Zn displacement plating treatment. When the coating amount is less than 5 mg / m ² , the adhesion with the Ni plating layer formed on the Zn layer becomes poor, and the plating layer is easily peeled off when bending is performed. On the other hand, when the coating amount exceeds 500 mg / m ² , the Ni plating becomes non-uniform and the solder strength decreases.

Next, a Ni layer is formed by plating on the Zn layer thus formed. Ni plating may be formed using either electroplating or electroless plating. When the electroless plating method is used, since a P compound or a B compound is used as a reducing agent, the Ni plating film is formed as a film made of a Ni-P alloy or a Ni-B alloy, but is made of pure Ni by electroplating. Similar to the coating, adhesion of the plating coating to the Al substrate, and excellent solder wettability and solder strength can be obtained. Thus Ni layer obtained is preferably 0.2 to 50 g / ^{m 2} as a film weight, and more preferably 1 to 10 g / ^{m 2.} If the coating amount is less than 0.2 g / m ² , the Ni layer cannot uniformly cover the entire surface of the Zn layer, and thus sufficient solder strength cannot be obtained. On the other hand, if the coating amount exceeds 50 g / m ² , the effect of improving the solder wettability and the solder strength is saturated, which is not advantageous in terms of cost.

  When Zn is plated as described above and then Ni is plated, Zn deposited on the Al substrate is slightly dissolved in the Ni plating bath during Ni plating. As a result of the increase in Zn, a Ni—Zn alloy is formed on the Zn layer formed by displacement plating. Although Zn dissolved in the Ni plating bath may be removed using a removing means, there is no particular problem even if a Ni—Zn alloy layer is formed on the Zn layer instead of the Ni plating layer.

Next, an Sn layer is formed on the Ni layer or the Ni—Zn alloy layer using a known electroplating method. The Sn layer is preferably 0.2 to ²⁰ g / m ² and more preferably 1 to 10 g / m ² in terms of the plating film amount. When the coating amount is less than 0.2 g / m ² , solder becomes difficult to wet when an inactive flux is used. On the other hand, when the coating amount exceeds 20 g / m ² , the effect of improving the solder wettability and the solder strength is saturated, which is not advantageous in terms of cost. Further, after forming the Sn plating layer, the adhesiveness may be improved by heating to a temperature lower than or higher than the melting point of Sn to form an alloy layer between the Ni layer and the Sn layer.

  In this way, a Zn layer, a Ni layer or a Ni—Zn alloy layer, and a Sn layer may be formed in order from the substrate side on the Al substrate, and the surface-treated Al thin plate for the hollow laminate of the present invention may be used. An organic resin layer such as urethane resin may be formed on the Sn layer in order to improve solderability. By forming the organic resin layer that improves the solderability, good solder bond strength can be obtained even when using Pb-free solder or low-melting-point solder having poor solder wettability than Pb-Sn solder. Become. That is, a water-based acrylic resin containing a water-based urethane resin or a water-soluble rosin is applied on the Sn layer and dried to form an organic resin layer. Since these organic resins have a flux effect, solder wettability is improved. The concentration of the aqueous resin is preferably 100 to 900 g / L. The dried organic resin layer preferably has a thickness of 0.01 to 1 μm. If it is less than 0.01 μm, a sufficient flux effect cannot be obtained, and if it exceeds 1 μm, the improvement of the flux effect is saturated and is not advantageous in terms of cost. Moreover, you may improve the thermal radiation effect of the surface by making these organic resin layers contain black pigments, such as carbon powder. As described above, the surface-treated Al plate for the hollow laminate of the present invention can be obtained.

  The hollow laminate of the present invention is formed by soldering and laminating at least two surface-treated Al thin plates adjacent to each other so as to form a hollow portion of a predetermined shape such as a tunnel shape, Obtainable. That is, as shown in FIG. 1, after grooving at least one surface 1a of the surface-treated Al thin plate to provide a grooved portion 2, or after applying the above surface treatment to a pre-grooved Al thin plate, Applying cream solder 3a to the portion 3 other than the groove processed portion, and contacting and laminating the other flat surface-treated Al thin plate 1b, and heating to a temperature equal to or higher than the melting point of the solder, the hollow having the hollow portion 4 The laminated body 10 can be obtained. It is preferable that the groove depth 2a of the groove processed portion is 1 mm or less.

  Further, as shown in FIG. 2, in the hollow laminated body 10, the hollow portion 4 is provided as a continuous loop-shaped tunnel, and water, pure, alcohol, etc. are sealed and sealed as a heat pipe operating body from the sealing port 4a. The plate-like cooling member 20 can be obtained. Thus, the plate type cooling member of the present invention is obtained. The plate type cooling member of the present invention can be suitably applied as a heat radiating member of an electronic device such as a notebook personal computer.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Creation of surface-treated aluminum sheet]
A meandering grooved portion as shown in FIG. 2 was formed on an Al thin plate (JIS 5052, thickness: 0.1 mm) by pressing. Etching treatment in which the Al thin plate in which the groove processed portion is formed and the flat Al thin plate having the same composition and the same thickness that does not form the groove processed portion are used as a plating base, degreased in an alkaline solution, and then immersed in sulfuric acid. And subsequently desmutting in nitric acid, sodium hydroxide: 150 g / L, Rochelle salt: 50 g / L, zinc oxide: 25 g / L, ferrous chloride: 1.5 g / L The same treatment as that used in the first Zn substitution plating treatment was performed after removing the Zn deposited by immersion in a 400 g / L aqueous nitric acid solution after performing the first Zn substitution plating treatment immersed in the treatment liquid. The Zn-plated Al thin plate in which a Zn layer having a coating amount of about 200 mg / m ² was formed was obtained by immersing in the solution and performing a second Zn substitution plating treatment.

Next, using an electroless plating method on these Zn-plated Al thin plates, a Ni-12 wt% P alloy plating film was formed on the Zn layer with a film amount of about 15 g / m ² , and subsequently the Zn layer and Ni An Sn plating film was formed on the Ni layer on the Al thin plate on which the layer was formed using the electroplating method under the conditions shown below at a film amount of about 5 g / m ² .

[Sn plating conditions]
Bath composition Stannous sulfate 30g / L
Phenolsulfonic acid 60g / L
Ethoxylated α-naphthol 5g / L
Anode Sn plate stirring Circulating bath temperature of plating bath 50-55 ° C
Current density 10A / dm ²

  Next, these Al thin plates on which the Zn layer, Ni layer, and Sn layer were formed were immersed in an aqueous urethane resin aqueous solution (resin concentration 550 g / L) and then dried to form an organic resin layer having a thickness of 0.3 μm. Formed. In this way, a surface-treated Al thin plate was prepared.

[Creation of hollow laminate]
Lead-free cream solder (M705 (Sn-3.0Ag-0.5Cu) melting point: 220 ° C.) on the portion other than the grooved portion on one side of the surface-treated Al thin plate on which the grooved portion formed as described above is formed. , Manufactured by Senju Metal Co., Ltd.), a flat surface-treated Al thin plate that does not form a grooved portion on the solder coating surface is abutted, inserted into an electric oven heated to 250 ° C., held for 30 seconds, and then removed. And allowed to cool. Thus, the hollow laminated body which has the hollow part of the meandering loop-shaped tunnel was created.

[Create heat pipe]
Isopropyl alcohol was sealed and sealed as a heat pipe working body from the sealing port of the hollow laminate produced as described above to obtain a plate-shaped heat pipe.

  The hollow laminate of the present invention in which a Zn layer, Ni layer or Ni—Zn alloy layer, and Sn layer are formed on an Al thin plate substrate in this order from the substrate side is obtained by soldering at least two surface-treated Al thin plates. A large pressure welding apparatus such as a hot rolling apparatus or a vacuum processing apparatus using a conventional clad material, in which a hollow portion having a predetermined shape is formed on opposite surfaces adjacent to each other. Can be manufactured as a hollow laminate at low cost. Therefore, by enclosing the heat pipe working body in the hollow portion of the hollow laminate of the present invention, the plate type cooling member can be manufactured easily and at low cost, and heat dissipation using the plate type cooling member is possible. Can be manufactured at low cost.

The schematic sectional drawing which shows an example of the hollow laminated body of this invention. The schematic plan view which shows an example of the cooling member of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a: Surface treatment Al thin plate 1b: Surface treatment Al thin plate 2: Groove processing part 3: Parts other than a groove processing part 3a: Cream solder 4: Hollow part 4a: Enclosure 10: Hollow laminated body 20: Cooling member

Claims (8)

A hollow laminated body in which at least two surface-treated Al thin plates are laminated by soldering, and a hollow portion having a predetermined shape is formed on the adjacent opposing surfaces. The hollow laminated body according to claim 1, wherein groove processing is applied to at least one of the surface-treated Al thin plates. The hollow laminate according to claim 1 or 2, wherein the surface-treated Al thin plate is formed by forming a Zn layer, a Ni layer, and a Sn layer in this order from the Al thin plate side. The hollow laminate according to claim 1, wherein the surface-treated Al thin plate is formed by forming a Zn layer, a Ni—Zn alloy layer, and a Sn layer in this order from the Al thin plate side. The hollow laminate according to claim 3 or 4, wherein an organic resin layer for improving solderability is formed on the Sn layer. The hollow laminate according to claim 5, wherein the organic resin layer is a urethane resin. The plate-type cooling member formed by enclosing a heat pipe operation body in the said hollow part of the hollow laminated body in any one of Claims 1-6. An electronic device using the plate-type cooling member according to claim 7.

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