JPH0614764U - Electrically insulated heat pipe - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a high-performance electrically insulated heat pipe without heat deformation to the heat pipe or the base plate. [Structure] An electric insulation type heat pipe in which electric current of a semiconductor element mounted on a base plate is prevented from flowing through a heat pipe to a heat radiation fin by interposing an electric insulation joint The joints at both ends of the insulation joint are made of a metal different from that of the aluminum member and other than copper, and the electric insulation joint is attached to the heat pipe or base plate by soldering with solder for the aluminum member at the joint portion. It is characterized by being joined and interposed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electrically insulated heat pipe in which a current of a semiconductor device mounted on a base plate does not flow to a heat radiation fin through a heat pipe.

[0002]

[Prior art and its problems]

 As shown in FIG. 10, in the heat pipe type heat exchanger, the inconvenience caused by the current flowing through the semiconductor element 12 mounted on the base plate 11 flowing through the heat pipe 13 to the heat radiating fins 14 is prevented. Therefore, it has been proposed to interpose an electric insulator (for example, ceramic) 10 in the middle of the heat pipe 13. That is, an electrically insulating heat pipe has been proposed (for example, JP-A-56-108098). In FIG. 10, a plurality of heat pipes 13 are provided side by side in the front-back direction of the paper.

By the way, the heat pipe 13 is preferably formed of an aluminum member (that is, aluminum or aluminum alloy) in order to reduce the weight of the heat exchanger itself and reduce the cost. However, since the electrical insulator and the aluminum member have greatly different coefficients of thermal expansion, if the two are directly joined, a crack may occur at the joined portion and the sealed state of the heat pipe 13 may be broken. Therefore, it has been proposed to join the electric insulator 10 and the heat pipe 13 by interposing a metal having a coefficient of thermal expansion intermediate between the two, for example, an iron-based metal (for example, JP-A-2-217791).

However, in the above, the interposing metal and the heat pipe 13 are joined by brazing, and the joining work must be performed at a relatively high temperature. There is a risk of thermal deformation, and there was a risk that the performance as a heat exchanger would deteriorate.

The base plate 11 is also preferably formed of an aluminum member, like the heat pipe 13. When the base plate 11 is formed of an aluminum member and the electrical insulator 10 is directly attached to the base plate 11 without the heat pipe 13, a metal to be interposed is required as described above. There is a risk that the base plate 11 may be thermally deformed.

[0006]

[The purpose of the device]

 It is an object of the present invention to provide a high-performance electrically insulated heat pipe that is free from thermal deformation of the heat pipe and the base plate.

[0007]

[Means for achieving the purpose]

 According to the invention of the present application, in a heat insulation type heat pipe in which a base plate having a mounting surface of a semiconductor element and a heat pipe to which a large number of heat radiation fins are fixed are attached via an electric insulation joint, The pipe and base plate are made of aluminum, and the electrical insulation joint is made of a cylinder made of electrical insulator and joints fixed to both ends of the cylinder.The joint is made of a metal different from that of the aluminum member. It is an electrically insulated heat pipe that is made of a metal other than copper and is characterized in that the electrically insulated joint is joined to the heat pipe and the base plate by soldering with a solder for the aluminum member at the joint portion.

Further, another invention of the present application is that a heat pipe having a large number of heat radiation fins is attached to a base plate having a mounting surface of a semiconductor element, and a heat pipe between the heat radiation fins and the base plate is in the middle of the heat pipe. In an electrically insulated heat pipe in which an electrically insulated joint is installed in the heat pipe, the heat pipe is made of an aluminum member, and the electrically insulated joint is composed of a tubular body made of an electrical insulator, and joint parts fixed to both ends of the tubular body. The joint part is made of a metal different from the aluminum member and other than copper, and the electrical insulation joint is joined to the heat pipe by soldering with a solder for the aluminum member at the joint part. It is an electrically insulated heat pipe that is characterized by

[0009]

[Action]

 In the invention of the present application, since the joint portion and the heat pipe and the base plate are joined by soldering, the heat pipe and the base plate are not exposed to the high temperature as in the case of brazing during the joining work. . Therefore, the heat pipe and the base plate are not thermally deformed.

In another invention of the present application, since the joint portion and the heat pipe are joined by soldering, the heat pipe is not exposed to a high temperature as in the case of brazing during joining work. Absent. Therefore, the heat deformation does not occur in the heat pipe.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an electric insulation type heat pipe according to the present invention. This electrically insulated heat pipe is different from that shown in FIG. 10 in that the electric insulation joint 15 is directly attached to the base plate 11 without the heat pipe 13. In FIG. 1, the same symbols as those in FIG. 10 indicate the same or corresponding parts. Both the base plate 11 and the heat pipe 13 are made of an aluminum alloy (for example, A6063, A1050). The base plate 11 has a hole 11 a communicating with the electrically insulating joint 15 and the heat pipe 13.

FIG. 2 is an exploded enlarged cross-sectional view of a main part of FIG. The electrical insulation joint 15 is composed of a tubular body 15a made of an electrical insulator (for example, ceramic), and joint portions 16 fixed to both ends of the tubular body 15a by brazing, for example. The joint portion 16 is made of Invar alloy (Fe-42% Ni alloy). The joint portion 16 has an L-shaped cross section and includes a tubular main body 16a and an outward flange 16b, and is fixed to the end surface of the tubular body 15a by the flange 16b.

The electrical insulation joint 15 is configured such that the main bodies 16a of the joint portions 16 on both sides are fitted into the large diameter portion 11b of the hole 11a of the base plate 11 and the large diameter portion 13a of the heat pipe 13, respectively. The heat pipe 13 and the joint portion 16 are soldered using Zn-5% Al, which is a solder for aluminum members, and are interposed between the heat pipe 13 and the base plate 11.

The above soldering is performed as follows. 3 to 7 are sectional views showing the method step by step. Although the soldering of the joint portion 16 and the heat pipe 13 is described here, the same applies to the soldering of the joint portion 16 and the base plate 11. First, as shown in FIG. 3, the outer surface of the main body 16a of the joint portion 16 of the electrically insulating joint 15 and the surface of the flange 16b on the opposite side of the tubular body 15a (hereinafter referred to as “the outer surface of the joint portion 16” as a whole). The copper plating layer 20 is formed on the substrate. This plating treatment is carried out by the usual methods, that is, the steps of degreasing, washing with water, electrolysis, washing with water and drying. The electrolysis conditions at that time are as shown in Table 1. By setting the electrolysis time to about 1 to 3 minutes, the copper plating layer 20 having a thickness of several μm was obtained.

[Table 1]

Next, as shown in FIG. 4, the joint portion 16 on which the copper plating layer 20 is formed is immersed in the molten solder 21, and ultrasonic vibration is applied through a suitable horn to the joint portion 16 or a solder bath. Add to 22. The melting point of the solder 21, which is Zn-5% Al, is about 380 ° C. The frequency of ultrasonic waves is about 17.6 KHz. Cavitation occurs by applying ultrasonic vibration. As a result, the solder 21 penetrates into the copper plating layer 20 and a metallurgical reaction occurs, and as shown in FIG. 5, the alloy layer 23 is formed and the plating layer 24 made of the solder 21 is formed. It That is, the solder plating layer 24 is formed on the outer surface of the joint portion 16 via the alloy layer 23.

On the other hand, as shown in FIG. 6, the plating layer 24 made of the solder 21 is formed on the inner surface and the end surface of the large diameter portion 13 a of the heat pipe 13. Similar to the case shown in FIG. 4, this plating treatment is performed by immersing the large diameter portion 13a in the molten solder 21 and applying ultrasonic vibration to the large diameter portion 13a or the solder bath 22.

Then, as shown in FIG. 7, the solder plating layer 24 of the joint portion 16 and the solder plating layer 24 of the large diameter portion 13a are combined to melt both plating layers 24 and the joint portion 16 or the large diameter portion 13a. The joint portion 16 and the large diameter portion 13 a, that is, the heat pipe 13 are joined by applying ultrasonic vibration to the joint portion 16.

In the soldering of the joint portion 16 and the base plate 11 as well, the solder plating layer 24 is formed on the joint portion 16 via the alloy layer 23 in the same manner as described above, while the solder plating layer 24 is formed on the wall of the large diameter portion 11 b of the base plate 11. Also, a solder plating layer 24 is formed, and both plating layers 24 are combined and melted as shown in FIG.

Thus, in the above method, the alloy layer 23 is formed by forming the copper plating layer 20, and the solder plating layer 24 is firmly bonded to the joint portion 16 made of Invar alloy by interposing the alloy layer 23. Adhere to. Therefore, the joint portion 16 and the heat pipe 13, and the joint portion 16 and the base plate 11 are joined by soldering through the solder plating layer 24.

The temperature for forming the solder plating layer 24 is about 400 ° C. for melting the solder 21, which is considerably lower than a general brazing temperature (about 600 ° C.). Therefore, no heat deformation occurs in the heat pipe 13, the base plate 11 and the joint portion 16. Therefore, the electrically insulated heat pipe of the invention of the present application has a high performance since the sealed state of the internal space consisting of the base plate 11, the electrically insulated joint 15 and the heat pipe 13 is reliably maintained.

Further, since the work can be performed at a lower temperature than the brazing work, workability is also good. Moreover, by applying ultrasonic vibration, the solder plating layer 24 is formed without using flux. Therefore, the post-treatment of the flux is unnecessary, and the heat pipe 13, the base plate 11, and the joint portion 16 are not corroded by the flux. Therefore, the electrical insulation type heat pipe of the present invention has good quality.

FIG. 9 is an exploded cross-sectional view of an essential part showing an electrically insulating heat pipe according to another invention of the present application. 9, the same reference numerals as those in FIG. 2 indicate the same or corresponding ones. In this electrically insulated heat pipe, an electrically insulated joint 15 is provided in the middle of the heat pipe 13, and joint portions 16 on both sides are soldered to the large diameter portions 13a of the heat pipes 13 on both sides. This soldering is performed in the same manner as in FIGS. The heat pipe 13 on the base plate 11 side is closed, inserted into the hole 11a, and joined to the wall surface of the hole 11a by, for example, soldering.

Also in this electrically insulated heat pipe, the heat pipes 13 on both sides are not thermally deformed. Therefore, this electrically insulated heat pipe has high performance because the internal space consisting of the base plate 11, the electrically insulated joint 15 and the heat pipe 13 is securely kept in a sealed state. Further, since soldering is performed as in FIGS. 3 to 7, no flux is required. Therefore, this electrically insulated heat pipe has good quality.

In both of the inventions, titanium, stainless steel or the like can be used for the joint portion 16, and aluminum or another aluminum alloy can be used as the aluminum member of the heat pipe 13 or the base plate 11. The solder plating layer 24 may be formed by using a flux instead of the ultrasonic vibration. Further, it is not always necessary to apply ultrasonic vibration when joining the joint portion 16 to the heat pipe 13 and the base plate 11.

[0025]

[Effect of device]

 As described above, in the electrically insulated heat pipe of the present invention, the electrically insulated joint 15 is joined to the heat pipe 13 and the base plate 11 by soldering at the joint portion 16. It has no deformation and has high performance.

In the electrically insulated heat pipe of another invention of the present application, since the electrically insulated joint 15 is joined to the heat pipe 13 by soldering at the joint portion 16, the heat pipe 13 is not likely to be thermally deformed. Instead, it has high performance.

[Brief description of drawings]

FIG. 1 is a side view showing an electrically insulating heat pipe of the present invention.

FIG. 2 is an exploded cross-sectional view of a main part of FIG.

FIG. 3 is a sectional view showing a first step for soldering a joint portion and a heat pipe.

FIG. 4 is a cross-sectional view showing a second step for soldering the joint portion and the heat pipe.

FIG. 5 is a cross-sectional view showing a third step for soldering the joint portion and the heat pipe.

FIG. 6 is a cross-sectional view showing a fourth step for soldering the joint portion and the heat pipe.

FIG. 7 is a cross-sectional view showing a fifth step for soldering the joint portion and the heat pipe.

FIG. 8 is a cross-sectional view showing a step for soldering the joint portion and the base plate.

FIG. 9 is an exploded cross-sectional view of an essential part showing an electrically insulating heat pipe according to another device of the present application.

FIG. 10 is a side view showing a conventional general electric insulation type heat pipe.

[Explanation of symbols]

 11 Base Plate 12 Semiconductor Element 13 Heat Pipe 14 Radiating Fin 15 Electrical Insulation Joint 15a Cylindrical Body 16 Joint Part

Claims (2)

[Scope of utility model registration request] 1. An electric insulation type heat pipe in which a base plate having a mounting surface of a semiconductor element and a heat pipe to which a large number of heat radiation fins are fixed are attached via an electric insulation joint. Is an aluminum member, and the electrical insulation joint is composed of a tubular body made of an electrical insulator and a joint portion fixed to both ends of the tubular body. The joint portion is a metal different from the aluminum member and other than copper. An electrically insulated heat pipe, characterized in that the electrically insulated joint is joined to the heat pipe and the base plate by soldering with a solder for an aluminum member at the joint portion. 2. A heat pipe, to which a large number of heat radiation fins are fixed, is attached to a base plate having a mounting surface of a semiconductor element, and an electrically insulating joint is provided in the middle of the heat pipe between the heat radiation fins and the base plate. In the electrically insulated heat pipe, the heat pipe is made of an aluminum member, the electrically insulated joint is made of a tubular body made of an electrical insulator, and joint portions fixed to both ends of the tubular body, and the joint portion is made of an aluminum member. An electric insulation type heat pipe characterized by being made of a metal different from copper and other than copper, and the electric insulation joint is joined to the heat pipe by soldering with a solder for an aluminum member at the joint portion. .