JPH0466390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improved heat pipe cooler for semiconductors and a method for manufacturing the same.

(Prior Art) A cooler using a heat pipe for cooling semiconductors such as thyristors was developed by the present inventors in Japanese Patent Application Laid-Open No. 1983-1999.
It is already known as No.-57956. As shown in Fig. 4, this heat pipe cooler for semiconductors has a heat pipe 1 made of a metal with good thermal conductivity such as copper, and fins 2 made of aluminum or the like with good thermal conductivity are inserted to form a heat dissipation part. The lower end of the heat pipe is inserted into a metal block 3 made of copper or the like with good thermal conductivity, and the heat generated from a semiconductor 4 such as a thyristor attached to the metal block is transferred to the heat pipe, and the heat is transferred to the heat pipe by a fin or a fan. This method increases the efficiency of semiconductors by forcing them to cool down. Note that a terminal 5 for taking out current is attached if necessary. Semiconductor surfaces of thyristors and the like normally have a potential, which is then energized through the metal heat pipe to the heat dissipation section, making it extremely dangerous to handle depending on the usage environment. Particularly recently, they have been sometimes installed in vehicles such as trains, which has caused safety problems. Therefore, attempts have been made to provide electrical insulation between a semiconductor such as a thyristor and a metal block by providing an insulating plate made of ceramic such as aluminum nitride, which has relatively good thermal conductivity. However, the above-mentioned aluminum nitride still had problems in terms of thermal performance, mechanical strength, reliability, etc.

(Means for Solving the Problems) The present invention was made in view of the above problems, and has one end narrowed into a hemispherical or conical shape and a nozzle at the tip, and a V-shaped groove on the inner surface. A heat dissipation section is formed by inserting a large number of fins into one or more heat pipes, one end of which is constricted into a hemispherical or conical shape below and sealed by welding, and an opening and an opening on the inner surface. A heat absorption section is formed by inserting one or more heat pipes each having a groove with a hollow section deep into the metal block, and an electrically insulating pipe is inserted between the heat dissipation section and the heat absorption section. This is a heat pipe cooler for semiconductors, which is connected to the heat pipe and whose working fluid is electrically insulating. The ends of one or more heat pipes have a V-shaped groove, and one end is squeezed into a hemispherical or conical shape and sealed by welding, and a strip has an opening on the inner surface and a cavity deep inside. The ends of one or more grooved heat pipes are connected with an electrically insulating pipe via a sealing metal, and after soldering and inserting a metal block to the lower end of the heat pipe, the end of the heat pipe is connected. Electrically insulating working fluid is injected through the nozzle, the metal block is heated to boil the working fluid and the inside of the heat pipe is degassed, the nozzle is sealed by caulking, and its tip is welded to form a heat pipe. This is a method of manufacturing a heat pipe cooler for semiconductors, which is characterized by inserting fins into a heat dissipating section. Further, in the above manufacturing method, after soldering and inserting a metal block to the lower end of the heat pipe, the inside of the heat pipe is evacuated through a nozzle at the tip of the heat pipe, and an electrically insulating working fluid is injected, and the nozzle is closed. This is a method of manufacturing a semiconductor heat pipe cooler, characterized by sealing it by caulking and welding its tip to form a heat pipe.

That is, the first invention connects the heat pipes of the heat radiation part and the heat absorption part with an inorganic electrically insulating pipe made of, for example, alumina, magnesia, glass, ceramic, etc. to prevent electrical leakage from the semiconductor of the heat absorption part. This is a heat pipe cooler for semiconductors that uses an electrically insulating pipe to prevent current from reaching the heat radiating section.

However, the heat pipe used in the above is made of copper, which has good thermal conductivity, for both the heat radiation part and the heat absorption part.
Metal such as aluminum. The inner surface of the heat pipe of the heat absorbing section is provided with a groove having an opening and a cavity deep inside the opening. In the groove, the working fluid flows from the narrow opening into the deep cavity in the endothermic part, where it is heated and causes nucleate boiling to form bubbles and evaporate. This increases nucleate boiling and promotes evaporation of the working fluid. Further, one of the heat dissipating parts is provided with V-shaped grooves, which speed up the reflux of the working fluid and expand the surface area, thereby improving heat dissipation. Therefore, it is better for the grooves mentioned above to be as fine as possible.
However, the heat pipe constituting the heat dissipation section described above has its upper end constricted into a hemispherical or conical shape and has a nozzle at its tip. Since the V-shaped groove provided on the inner surface of the pipe extends to the end, the efficiency as a heat pipe is increased. The nozzle at the tip is for injecting hydraulic fluid. Furthermore, the reason why the lower end of the heat pipe in the heat absorption part is constricted into a hemispherical or conical shape is because the grooves provided on the inner surface of the heat pipe extend all the way to the end, as in the case of the heat dissipation part described above, which improves evaporation efficiency. It will improve.

However, in the method for manufacturing a heat pipe cooler for semiconductors according to the second invention, first, V-shaped grooves are formed on the inner surface of a metal tube made of copper, aluminum, etc. with good thermal conductivity by pulling a plug, and the outer diameter is adjusted to a desired value. Finish to size. Next, one end of this pipe is formed into a hemispherical or conical shape by spinning, and a nozzle having a small hole is formed at the tip thereof to form a hydraulic fluid injection part. In addition, for the heat pipe in the heat absorption section, a V-shaped groove is first formed by pulling a plug, and then a groove with an opening and a cavity inside is formed by crushing the mountain part by pulling a spherical plug. .
Next, this one end is formed into a hemispherical or conical shape by spinning, and the tip is sealed by welding.

Alumina, magnesia,
Connect inorganic electrically insulating pipes made of glass, ceramic, etc. Next, the lower end of the metal block, such as copper or aluminum, with good thermal conductivity is inserted into a hole drilled to match the outer diameter of the heat pipe, and soldered to secure the metal block and the heat pipe. After this, an electrically insulating working fluid such as Freon 113 is injected through the nozzle at the tip of the heat pipe, and then the metal block is heated to 50°C or higher, the boiling temperature of the working fluid, to boil the Freon, and the inside of the heat pipe is degassed. The heat pipe is sealed by caulking, and the tip is welded to form a heat pipe.

The process of making the heat pipe described above must be done after soldering the heat pipe and the metal block.
This is because the heat pipe will also be heated to the nearby temperature and the freon will decompose and will no longer function as a working fluid. However, the above method of making a heat pipe is not a method of heating and degassing, but after soldering the heat pipe and a metal block, the inside of the heat pipe is evacuated by a vacuum pump via a heat pipe nozzle, and then Freon etc. It is also possible to inject electrically insulating working fluid, seal the nozzle by caulking, and weld the tip to form a heat pipe. After this, fins are inserted into the heating section to form a cooler.

In addition, in the heat pipe cooler for semiconductors of the present invention, the heat pipe may be placed either vertically or horizontally, and even when the heat pipe is placed horizontally, the grooves are provided on the inner surface of the heat pipe, so that this effectively acts as a wick. This improves heat dissipation. Further, the heat dissipation fins may be inserted before installing the electrically insulating pipe.

(Example) An embodiment of the present invention will be described below.

As shown in Fig. 1a, the upper end of a copper heat pipe 1 with an outer diameter of 15.88 mm is formed with a V-shaped groove with a peak height of 0.3 mm and a pitch of 0.6 mm in the axial direction on the inner surface by plugging. It is formed into a hemispherical shape by spinning, and a nozzle 6 having a small hole is provided at the tip thereof by spinning to form a heat pipe 1 as a heat dissipation section. Next, the height of the mountain is 1.0 by pulling the plug.
After forming V-shaped grooves with a pitch of 1.5 mm,
The height of the mountain is increased by pulling the plug with a spherical plug.
A groove with an opening of 0.65 mm and a pitch of 1.5 mm and a hollow part inside the opening was provided. A heat pipe 1' is fabricated at the lower end of the heat pipe 1', which is similarly formed into a hemispherical shape by spinning and whose tip is sealed by welding.
An alumina pipe 8 to which the sealing material Kovar 7, 7' is brazed is inserted between the heat pipes 1 and 1', and the heat pipe and the Kovar part are brazed and joined by high frequency heating to form the heat pipes 1 and 1'. Link. Next, as shown in FIG. 1B, one end 120 mm of this integrated heat pipe 1 is inserted into a perforated aluminum metal block 3 and brazed with a soft solder material 9 to form a heat absorption section. Next, as shown in Fig. 1c, Freon working fluid 10 is injected from the nozzle 6 at the upper end of the heat pipe, and then, as shown in Fig. 2a, the metal block 3 is heated to 50°C or higher with a heater. The inside of the heat pipe is degassed by boiling the working fluid, the nozzle 6 at the tip is caulked with a crimping jig, and the upper end is welded by TIG welding to form a heat pipe. After this, the second
As shown in FIG. b, a large number of aluminum fins 11 are inserted above the heat pipe to serve as a heat dissipation section.

As shown in FIG. 3, the semiconductor heat pipe cooler manufactured in this manner has a heat pipe 1 with a large number of fins 2 inserted therein to form a heat dissipation section, and a metal block 3 inserted below the fins 2. The heat pipe 1' forms a heat absorbing part, and the structure is such that an electrically insulating pipe 8 is connected between the heat pipes 1'.

Heat generated by a semiconductor 4 such as a thyristor is transmitted to a heat pipe 1' via a metal block 3, and is radiated by a heat radiating portion of the heat pipe 1. At this time, since the electrically insulating pipe 8 is provided, only heat is transferred to the upper heat radiating section, and since it is electrically insulated, there is no risk of electric shock. Furthermore, since the hydraulic fluid is electrically insulating, safety is ensured in this respect as well. The heat pipe 1 in the heat dissipation section is provided with V-shaped grooves on its inner surface, the cross section of which is shown in Figure 3c, improving heat dissipation. has an opening 11 on the inner surface as shown in FIG. 3D in cross section.
Since a groove having a cavity 12 is provided in the depth thereof, heat absorption is improved.

(Effects) According to the present invention, even if a semiconductor such as a thyristor is directly attached to the metal block surface, it is electrically insulated in the middle of the heat pipe, so only the heat is transferred without the potential of the thyristor being transmitted to the heat dissipation part. Therefore, dangers such as electric shock can be prevented. Thermal performance is also improved because the semiconductor can be attached directly to the metal block.

Furthermore, since special grooves are provided on the inner surface of the heat pipe, the heat dissipation and heat absorption properties are further improved.

Furthermore, since the end of the heat pipe is formed into a hemispherical or conical shape, the grooves extend to the end, which increases the effective area compared to one with a flat end, increasing the performance of the heat pipe. It is.

In addition, in the manufacturing method, since the heat pipe is formed after the metal block and the heat pipe are soldered, the problem of the sealed hydraulic fluid not working can be solved.

Furthermore, since the heat pipe is provided with a nozzle having pores, it has many advantages, such as improved workability in injection and sealing of the working fluid, and has a significant industrial effect.

[Brief explanation of drawings]

Fig. 1 a, b, c and Fig. 2 a, b are diagrams showing the steps of the manufacturing method of a heat pipe cooler for semiconductors of the present invention, respectively, and Fig. 3 shows a heat pipe cooler for semiconductors of the present invention. Figure a is a front view, b
is a plan view, and c and D are cross-sectional views of the heat pipe. FIG. 4 shows a conventional heat pipe cooler for semiconductors, in which a is a front view and b is a plan view. 1, 1'...Heat pipe, 2...Fin, 3
...Metal block, 4...Semiconductor, 5...Terminal,
6... Nozzle, 7,7'... Kovar, 8... Electrical insulation pipe, 9... Solder, 10... Working fluid,
11...Opening part, 12...Cavity part.

Claims (1)

[Claims] 1. A large number of fins are inserted into one or more heat pipes having one end constricted into a hemispherical or conical shape and having a nozzle at the tip and a V-shaped groove on the inner surface. to form a heat dissipation section, one end of which is squeezed into a hemispherical or conical shape below and sealed by welding.
In addition, one or more heat pipes each having an opening on the inner surface and a groove having a cavity deep inside the heat pipe are inserted into the metal block to form a heat absorption part, and the middle between the heat radiation part and the heat absorption part is formed. A heat pipe cooler for semiconductors, characterized in that it is connected by an electrically insulating pipe and the working fluid is electrically insulating. 2 The end of one or more heat pipes with one end constricted into a hemispherical or conical shape and having a nozzle at the tip and a V-shaped groove on the inner surface, and one end with a hemispherical or conical end The ends of one or more heat pipes are sealed by welding, and have an opening on the inner surface and a groove with a cavity deep inside the heat pipe. After soldering and inserting a metal block to the lower end of the heat pipe, electrically insulating working fluid is injected from the nozzle at the tip of the heat pipe, and the metal block is heated to boil the working fluid and the heat pipe is heated. A method for manufacturing a heat pipe cooler for semiconductors, comprising: deaerating the inside, sealing the nozzle by caulking, welding the tip thereof to form a heat pipe, and inserting fins into the heat radiation part. 3 After soldering and inserting a metal block to the lower end of the heat pipe, the inside of the heat pipe is evacuated through the nozzle at the tip of the heat pipe, and electrically insulating working fluid is injected, and the nozzle is sealed by caulking. 3. The method of manufacturing a semiconductor heat pipe cooler according to claim 2, wherein the tip of the heat pipe is welded to form a heat pipe.