JP2012227365A - Pin-like fin integrated type heat sink, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pin-like fin integrated type heat sink having satisfactory moldability of pin-like fins, securing mounting strength and proof stress, and having a plate-like part easily plastic-deformable to the thermal expansion and contraction of electric components, and a method for manufacturing the same.SOLUTION: A pin-like fin integrated type heat sink is made of pure copper having a copper purity of not less than 99.90 mass%, and has a plate-like part 2 of which one surface side is provided with a number of erected pin-like fins 3, and at least a part of the peripheral part 7 of the plate-like part 2 has a 0.2% proof stress which is twice to five times of that of the center part of the plate-like part. The pin-like fin integrated type heat sink is manufactured by: a heating step for heat treatment of metallic material; a hot forging step for forging the metallic material after heat treatment on a molding die having a number of holes to make at least a part of the peripheral part of the plate-like part thick-walled and to mold pin-like fins 3 in a part except the thick-walled part and a thin-walled fin erecting part 5 where the pin-like fins are erected; and a cold forging step for forging the thick-walled part in a cold condition to mold the peripheral part of the plate-like part.

Description

  The present invention relates to a heat sink used for cooling electronic components that generate heat, such as a large-scale integrated circuit (LSI), and more specifically, a pin-shaped fin integrated heat sink in which pin-shaped fins for heat dissipation are integrally formed, and the heat sink It relates to a manufacturing method.

In an electronic component that generates heat, such as a large-scale integrated circuit (LSI), a heat sink or a heat spreader that dissipates heat is attached to operate the electronic component normally. As these materials, aluminum or copper having high thermal conductivity, light weight and good workability is used.
In Patent Document 1, as a copper alloy for heat spreader (heat sink), 0.2% proof stress is 100 to 200 N / mm ² , thermal conductivity is 350 W / m · K or more, work hardening index is 0.14 to 0.18, A Cu-based alloy having a grain size in the width direction of the rolled surface plate of 25 μm or less is disclosed. Further, at least one of Fe, Ni, Co and P and 0.05 to 0.3 wt% in total are contained, the balance is made of Cu and inevitable components, and 600% after cold forging with a cross-sectional reduction rate of 40% or less. When the crystal grain size after heat treatment at 30 ° C. for 30 minutes is 25 μm or less and the Vickers hardness after heat treatment at 600 ° C. for 30 minutes after cold forging with a cross-section reduction rate of 40% or less is preferably HV 60-170 Have been described.
In addition, as such a heat sink, there is one in which fins for heat dissipation are formed in a pin shape, and a large number of pin-shaped fins are provided in an upright state on a plate-like portion serving as a base. Methods described in Document 2 and Patent Document 3 are known.

  Patent Document 2 discloses a heating process in which heat treatment is performed on a metal material, a forging process in which the metal material after the heat treatment is forged using a mold into a desired shape, and the metal material after the molding is ejector pins. And an extrusion process for extruding the mold outward, and a concave portion for forming a metal material into a flat plate shape by pressure during the forging process is provided inside the mold, and the metal material is formed at the lower surface of the concave section by the pressure during the forging process. A number of holes are formed to form a pin shape by stretching the ejector pin, and at the time of the forging process, ejector pins are inserted into all the holes of the mold from the outside of the mold, and the outer diameter of the ejector pin is set to the mold. A manufacturing method is disclosed in which a gap is defined between the outer peripheral surface of the ejector pin and the inner peripheral surface of the hole portion of the mold by making it 0.05 mm smaller than the inner diameter of the hole portion.

  According to this manufacturing method, even a metal material having a large deformation resistance at room temperature can be forged with a small deformation resistance. Therefore, it is possible to make the fin pitch fine or to manufacture a large heat sink. It becomes possible.

  On the other hand, Patent Document 3 discloses a technique for forging a large number of pins with a forming die and a punch, and in this case, a knockout pin (ejector pin) is inserted into each hole of the forming die. In addition, as a countermeasure against die hole clogging and uneven pin height, the surface roughness of the bearing part of the forming die is 0.05 μm or less, and the die exit wall is given “relief” to provide a die inner wall and pin material. The friction is made as close to zero as possible.

JP 2003-277853 A JP 2010-129774 A Japanese Patent No. 28828234

  Such a pin-shaped fin-integrated heat sink is fixed to structural members of various devices by screws or the like, and in the case of water cooling, it is necessary to support the pressure of the water flow acting on the fins by the screws. For this reason, strength for mounting and resistance to external force are required. However, when a high-strength material such as that described in Patent Document 1 is used, a large pressure is required even during forging, and formability is reduced. In addition, an electronic component is joined to the plate-shaped portion at the center of the plate-shaped portion opposite to the fin, and the electronic component thermally expands and contracts. On the other hand, the central part of the plate-like part is required to be soft enough not to cause an excessive stress on the electronic component by being easily plastically deformed.

  The present invention has been made in view of the above-described circumstances, and has a good moldability of the pin-shaped fins, ensures the mounting strength, and prevents the plate-like portion from being thermally expanded and contracted by the electronic component. An object of the present invention is to provide a pin-like fin-integrated heat sink in which a central portion can be easily plastically deformed and a method for manufacturing the same.

  The pin-shaped fin-integrated heat sink of the present invention is made of pure copper having a purity of 99.90% by mass or more, and a large number of pin-shaped fins are erected on one surface side of the plate-shaped portion, and the peripheral portion of the plate-shaped portion At least a part of is characterized in that the 0.2% proof stress is 2 to 5 times that of the central part of the plate-like part to which the electronic component is joined.

Pure copper having a purity of 99.90% by mass or higher has high thermal conductivity, is soft, and is easily plastically deformed. Therefore, pin-shaped fins can be formed with high accuracy by forging. In addition, after the electronic component is joined, the central portion of the plate-like portion to which the electronic component is joined is easily plastically deformed against thermal expansion and contraction of the electronic component, so that no excessive stress is generated in the electronic component. be able to. On the other hand, the portion where the 0.2% proof stress at the peripheral part of the plate-like part is 2 to 5 times that of the central part of the plate-like part can be used as an attachment part to the structural material of various devices, and as a member The strength of can be improved. Among pure copper, oxygen-free copper having a purity of 99.96% by mass or more and oxygen-free copper for electron tubes having a purity of 99.99% by mass or more are more preferable.
A copper-based alloy with a purity of less than 99.90% by mass has an increased mechanical strength as a whole due to precipitation hardening or solid solution strengthening, but the central portion of the plate-like portion undergoes plastic deformation due to thermal expansion and contraction of electronic components. Since it becomes difficult, it is not preferable.

Furthermore, the pin-like fin-integrated heat sink of the present invention is characterized in that the surface roughness of the peripheral portion of the plate-like portion is an arithmetic average roughness Ra of 0.1 μm to 6.3 μm.
When the arithmetic average roughness Ra is 0.1 μm to 6.3 μm, it is liquid-tightly attached to various devices via a packing attached to the water-cooled box side in which the pin-shaped fin-integrated heat sink is accommodated. The sealing property against the refrigerant is particularly excellent.
When the arithmetic average roughness Ra exceeds 6.3 μm, the sealing property tends to be lowered, and when the arithmetic average roughness Ra is less than 0.1 μm, the effect is saturated and wasted.

  The manufacturing method of the pin-shaped fin-integrated heat sink of the present invention includes a heating step of heat-treating a metal material, and forging the metal material after heat treatment on a forming die having a large number of fin-forming holes. Heat for forming at least a part of the peripheral part of the plate-like part into a thick part, and forming the pin-like fin and the thin-walled fin standing part in the part excluding the thick part. It has a cold forging process and the cold forging process which shape | molds the peripheral part of the said plate-shaped part by forging the said thick part cold.

  That is, the metal material is heated, and the pin-shaped fin and the fin standing portion for standing the pin-shaped fin excluding at least a part of the peripheral portion of the plate-shaped portion are hot forged and formed, and then At least a part of the peripheral part of the plate-like part is forged and formed cold. By keeping the metal material in a state where it can be easily plastically deformed hot, pin-shaped fins, etc. are precisely formed, and the parts that require mechanical strength because they are screwed etc. as a product Work and harden to obtain the required strength and yield strength. Further, by molding in the cold, the surface roughness of the peripheral portion of the plate-like portion can be easily reduced, and the packing attached to the water-cooled box side in which the pin-like fin integrated heat sink is accommodated It is liquid-tightly attached to various devices, and has excellent sealing properties against coolant by water cooling.

  According to the present invention, while having good moldability of pin-shaped fins, the strength and proof strength are ensured at the peripheral portion attached to various devices, and the center of the plate-like portion against thermal expansion and contraction of electronic components It is possible to obtain a pin-shaped fin-integrated heat sink in which a portion can be easily plastically deformed.

The pin-shaped fin integrated heat sink of one embodiment of the present invention is shown, (a) is a perspective view seen from the pin-shaped fin side, (b) is a perspective view seen from the flat surface side of the plate-like part. is there. It is a disassembled perspective view which shows the example of attachment to the water cooling box of the heat sink of FIG. It is a longitudinal cross-sectional view of the fin molding die used for the hot forging process for manufacturing the pin-shaped fin integrated heat sink of one Embodiment of this invention, (a) has arrange | positioned the metal material to the fin molding die The state is shown, and (b) shows the state of hot forging. It is a longitudinal cross-sectional view which shows the peripheral part shaping | molding die used for the cold forging process with respect to the intermediate molded object obtained by the hot forging process of FIG. 3, (a) arrange | positions an intermediate molded object to a peripheral part shaping | molding die (B) shows a state where cold forging is performed.

Hereinafter, embodiments of the present invention will be described.
As shown in FIG. 1, the pin-shaped fin-integrated heat sink 1 has a large number of pin-shaped fins 3 erected on one surface side of the plate-like portion 2. In the illustrated example, the pin-like fins 3 arranged in a row are formed so as to be shifted by a half pitch for each row to form a staggered arrangement. These dimensions are not particularly limited, but the plate-like portion 2 is formed to have a length of 133 mm, a width of 77 mm, and a thickness of 5 mm, for example, and the pin-like fin 3 has an outer diameter of 1.5 mm to 2 mm, The height is 6 mm to 8 mm and the pitch is 4 mm to 5 mm.

  As the material, pure copper having a purity of 99.90% by mass or more is used. As impurities, there are cases where As, Sb, Bi, Pb, S, Fe, O, P, and the like are included. In particular, since O and P are trace amounts and the plastic deformability is lowered, the amount of O is 500 ppm or less, preferably It is desirable that the amount is 100 ppm or less and the amount of P is regulated to 150 ppm or less, preferably 50 ppm or less. Tough pitch copper, oxygen-free copper, and phosphorus deoxidized copper can be cited as suitable materials, but oxygen-free copper having a purity of 99.96% by mass or more and oxygen-free copper for electron tubes having a purity of 99.99% by mass or more are more preferable.

Further, the peripheral portion 7 around the fin standing portion 5 where the pin-like fins 3 of the plate-like portion 2 are erected is set to have a surface roughness of 0.1 μm to 6.3 μm in terms of arithmetic average roughness Ra. ing.
Furthermore, a through-hole 8 for screwing that is an attachment portion to various devices is formed in the peripheral portion 7 of the plate-like portion 2. The peripheral edge portion 7 of the plate-like portion 2 in which the through-hole 8 is formed has a mechanical strength larger than that of the central portion 9 of the plate-like portion 2 on the inner side, and the 0.2% proof stress is at least a plate. Compared with the central portion 9 of the shape portion 2, the ratio is 2 to 5 times. For example, while the 0.2% proof stress of the central portion 9 of the plate-like portion 2 is ^{35N / mm 2 ~70N / mm 2} , the peripheral edge 7 of the plate portion 2 is 100N ^/ mm 2 ~200N ^/ mm ² . Further, the Vickers hardness is formed such that the central portion 9 of the plate-like portion 2 is 45Hv to 60Hv, whereas the peripheral portion 7 is formed to be 60Hv to 170Hv.
The central portion 9 of the plate-like portion 2 is affected by the work hardening caused by cold forging in the cold forging described later. The inside part is said. Although depending on the size of the pin-shaped fin 3 and the plate thickness of the plate-shaped portion 3, as shown by the chain line in FIG. 1B or as shown in FIG. 4B, for example, the pin-shaped fin 3 The innermost part of the outermost part of the outermost part of the outermost part of the inner part of the part.
Then, an electronic component (not shown) is mounted by soldering or the like on a flat portion on the other surface side where the pin-like fins 3 are not formed in the central portion 9 of the plate-like portion 2, and the heat is transmitted through the plate-like portion 2. Is transmitted to each pin-shaped fin 3 and is dissipated from the outer peripheral surface of the plate-shaped portion 2 and each pin-shaped fin 3.

  The pin-like fin-integrated heat sink 1 configured in this way is attached to a cooling box 31 as shown in FIG. 2, for example. The cooling box 31 is formed with an opening 32 for attaching the pin-like fins 3 of the heat sink 1 in an inserted state, and a packing receiving groove 33 is formed so as to surround the opening 32. Further, a screw hole 34 is formed on the outer side, and the heat sink 1 is arranged so that the pin-like fin 3 faces downward in FIG. 2 as shown by a chain line arrow, and the plate-like portion 2 is inserted into the opening 32. In this configuration, the surface around the opening 32 is brought into close contact with the packing 35 and fixed by screwing. In the illustrated example, two heat sinks are attached, and a cooling medium flows as indicated by arrows to cool the pin-like fins 3 of the heat sink 1 in the inserted state.

The manufacturing apparatus for manufacturing the pin-shaped fin integrated heat sink 1 excluding the peripheral portion 7 of the plate-like portion 2 and hot-forging the inner fin standing portion 5 and the pin-like fin 3 to form them. A fin forming die 11, and a peripheral portion forming die 14 for forging and forming the peripheral portion 7 of the plate-like portion 2 in the cold with respect to the intermediate formed body 12 formed by the fin forming die 11; Consists of
As shown in FIG. 3, the fin molding die 11 includes a molding die 16 having a number of concave fin molding holes 15 for forming the pin-shaped fins 3 in a forging press (not shown), and this molding. A punch 17 for forging the metal material M placed on the die 16 and an ejector pin 18 provided on the forming die 16 so as to be vertically movable are provided.

The molding die 16 has a concave portion 19 in which the metal material M is disposed at the time of forging on the upper surface portion thereof, and each fin molding hole 15 is formed on the bottom surface of the concave portion 19 in communication with the concave portion 19.
The punch 17 is moved up and down from above the forming die 16 by a hydraulic mechanism (not shown) and presses the metal material M in the recess 19 of the forming die 16. In this case, the plane area of the punch surface 17a on the lower surface of the punch 17 is smaller than the concave portion 19 of the forming die 16, and is large enough to strongly press the fin standing portion 5 excluding the peripheral edge portion 7 of the plate-like portion 2. The relief portion 20 is formed around the punch surface 17a so as to be recessed upward, and determines the thickness of the peripheral portion after hot forging.
The ejector pin 18 is configured to push up the peripheral portion of the intermediate molded body 12 after forging from below by a hydraulic mechanism (not shown) or the like.

On the other hand, as shown in FIG. 4, the peripheral portion molding die 14 further forges the intermediate molded body 12 in which the pin-shaped fins 3 and the fin standing portions 5 are forged by the fin molding die 11. A molding die 27 having a plurality of concave hole portions 25 for allowing each pin-shaped fin 3 to face a forging press (not shown), and having a molding concave portion 26 so as to communicate with the hole portions 25; A punch 28 for forging the intermediate molded body 12 on the concave portion 26 of the molding die 27 and an ejector pin 29 for pushing up the product from the molding die 27 after forging are provided.
The concave portion 26 of the forming die 27 forges the thick portion 13 of the peripheral portion 7 of the plate-like portion 2 formed at the time of forging by the fin molding die 11, and the inner peripheral surface of the concave portion 26 is plate-like. The outer peripheral surface of the part 2 is formed. The concave hole 25 accommodates the pin-shaped fin 3 so that the pin-shaped fin 3 is not displaced during forging. Further, this fitting is an accurate positioning of the material in cold forging.
The punch 28 is formed on a flat surface having a lower punch surface 28 a having a flat area of the plate-like portion 2, and the intermediate-shaped body 12 is forged on the concave portion 26 of the forming die 27 to form the plate-like portion 2. .
The ejector pin 29 is inserted into the molding die 27 so as to be vertically slidable, and is lifted by a hydraulic mechanism (not shown) after forging to push the product up from the molding die 27.

A method of manufacturing the pin-shaped fin-integrated heat sink 1 using the fin molding die 11 and the peripheral portion molding die 14 thus configured will be described.
In this manufacturing method, a heating step of heating the metal material M, and the heated metal material M is forged by the fin molding die 11, and one of the metal materials M is placed in the molding hole 15 of the molding die 16. A hot forging process in which mainly the pin-like fins 3 and the fin standing part 5 of the plate-like part 2 are formed by pushing the part, and the peripheral part 7 which is thick in this hot forging process is formed into the peripheral part. And a cold forging process in which the metal mold 14 is forged in the cold. Hereinafter, it demonstrates in order of a process.

<Heating process>
In the heating process, in order to reduce the deformation resistance of the metal material M, the metal material M is heated to a temperature equal to or higher than the recrystallization temperature of the metal material.

<Hot forging process>
As shown in FIG. 3A, when the heated metal material M is placed in the concave portion 19 of the molding die 16 of the fin molding die 11 and pressed so as to be struck by the punch 17, it is shown in FIG. 3B. As described above, the metal material M is crushed by the forming die 16 and the punch 17, and the fin standing portion 5 at the center portion of the plate-like portion 2 is formed to be thin while spreading in the concave portion 19, and a part of it is formed. The outer shape of the pin-shaped fin 3 is formed by press-fitting into the fin forming hole 15. Since this forging process is performed hot, the fluidity of the metal material M is good, and the pin-shaped fins 3 having a small diameter can be accurately formed.
By this hot forging process, the intermediate molded body 12 having the fin standing part 5 and the pin-like fin 3 excluding the peripheral part 7 of the plate-like part 2 is formed in the final product, and the peripheral part 7 of the plate-like part 2 is formed. The part to be formed is formed by the relief part 20 of the punch 17 to become the thick part 13.

  Next, the punch 17 is retracted upward, the ejector pin 18 is raised, and the intermediate molded body 12 is pushed up from the molding die 16.

<Cold forging process>
After cooling the intermediate molded body 12 obtained by the hot forging process, as shown in FIG. 4A, the pin-shaped fins of the intermediate molded body 12 are inserted into the holes 25 of the molding die 27 of the peripheral portion molding die 14. The plate-like portion 2 is placed in the concave portion 26 in a state where all 3 are arranged. In this state, since the peripheral portion of the plate-like portion 2 is the thick portion 13, the thick portion 13 bulges upward from the fin standing portion 5. Then, as shown in FIG. 4B, the thick portion 13 is forged so as to have the same thickness as the fin standing portion 5, thereby increasing the thickness between the punch 28 and the concave portion 26 of the forming die 27. The meat portion 13 is compressed, and the peripheral portion 7 of the plate-like portion 2 is formed by these inner peripheral surfaces. At this time, the fin standing part 5 of the plate-like part 2 has already been formed in the previous hot forging process, and the thick part 13 is forged up to the thickness of the fin standing part 5. It does not deform in the cold forging process. Further, by forging in the cold, the surface of the peripheral edge portion 7 of the plate-like portion 2 is formed with a surface roughness of 0.1 μm to 6.3 μm in terms of arithmetic average roughness Ra.
Next, the product is pushed up from the molding die 27 by retracting the punch 28 upward and raising the ejector pin 29.

The pin-shaped fin-integrated heat sink 1 manufactured in this way has an electronic component on the central portion 9 of the plate-like portion 2 which is the surface opposite to the surface where the pin-like fins 3 are erected in the fin-raised portion 5. Is mounted, and the peripheral portion 7 of the plate-like portion 2 is fixed to the water-cooled box 31 via the packing 35 by screws or the like so that the pin-like fins 3 are inserted into the water-cooled box 31. The electronic component is a component composed of a semiconductor chip, a circuit board, etc., and the water cooling box 31 has a cooling medium such as water circulating therein, and the pin-like fins 3 are immersed in the cooling medium to dissipate heat. Facilitate.
In this attached state, the peripheral edge portion 7 of the plate-like portion 2 fixed to the water-cooled box 31 is work-hardened by cold forging (see the cross-hatched portion in FIG. 4B) and has a 0.2% proof stress. Since it is formed two to five times as large as the central portion 9 of the plate-like portion 2, it can be firmly fixed without causing deformation or the like. Further, the peripheral edge portion 7 of the plate-like portion 2 of the heat sink 1 that is in close contact with the packing 35 accommodated in the packing accommodation groove 33 of the water-cooled box 31 is formed with an arithmetic average roughness Ra of 0.1 μm to 6.3 μm. Therefore, it is possible to ensure excellent sealing performance with the water cooling box 31.
In addition, when used for a long period of time, heat expansion and contraction occurs due to heat generation of the electronic component, temperature change of the surrounding environment, etc., but the central portion 9 of the plate-like portion 2 to which the electronic component is fixed is formed by hot forging, Since it is not deformed in the cold forging process, the central portion 9 of the plate-like portion 5 is easily maintained against the thermal expansion and contraction of the electronic component so as to be kept relatively soft and reduce the thermal expansion and contraction difference with the electronic component. It is possible to suppress the occurrence of thermal stress generated in the electronic component by plastic deformation.

Oxygen-free copper (purity 99.99 wt% or more) is used as the metal material, and the heat sink has a plate-like portion with a length of 133 mm, a width of 77 mm, and a thickness of 5 mm. The pin-like fin has an outer diameter of 1.5 mm. A pin-shaped fin with a height of 8 mm and a pitch of 4 mm, with the pin-like fins arranged in a row shifted by a half pitch for each row was molded into a staggered arrangement.
An ingot of oxygen-free copper (purity 99.99 wt% or more) was heated to 700 ° C. and then hot forged by a fin molding die to form a fin standing portion and a pin-shaped fin. The pressure during this hot forging was set to 100 MPa to 150 MPa. Next, cold forging was performed with a plate-shaped peripheral portion molding die, the peripheral portion of the plate-shaped portion was formed, and the surface roughness was changed to prepare heat sinks of Samples 1 to 6. The pressure during this cold forging was set to 200 MPa to 500 MPa.
As a comparative example, after heating an ingot of oxygen-free copper (purity 99.99 wt% or more) to 700 ° C., using a mold in which the fin standing part and the pin-like fin and the plate-like peripheral part can be integrally formed These were integrally formed only by hot forging and not by cold forging, and heat sinks of Sample 7 and Sample 8 were produced. In Table 1, for the samples 7 and 8, the fins, the fin standing portion, and the plate-like peripheral portion are shown as hot, but these are shown to be hot forged integrally.
With respect to the heat sinks of Samples 1 to 8 thus produced, 0.2% yield strength ratio (0.2% yield strength value of the plate-like peripheral portion / 0.2% yield strength value of the central portion of the plate-like portion), sealing property The thermal cycle performance was evaluated.
The 0.2% proof stress value was measured according to JIS Z 2241.
The sealability was determined by fixing the heat sink to a water-cooled box (with packing), measuring 500 kPa in the water-cooled box for 30 minutes, and measuring the presence or absence of pressure drop due to leakage. The case where leakage was not recognized even when the pressure was increased to 700 kPa over 30 minutes was marked as ◎, and the case where leakage was observed at a pressure of 500 kPa for 30 minutes was marked as x.
The heat cycle property is that an electronic component is soldered to the central portion of the plate-like portion of the heat sink, and the temperature change from −65 ° C. to 125 ° C. is repeated 500 cycles in accordance with JIS C0025, and the solder joint is peeled off or cracked. Observed. A sample in which no peeling or cracking was observed was marked with ○, and a sample in which these were recognized was marked with ×.
These results are shown in Table 1.

  As is clear from the results shown in Table 1, the pin-shaped fin-integrated heat sink of the present invention secures the mounting strength while maintaining the good moldability of the pin-shaped fin, and stresses due to thermal expansion and contraction of the electronic component. It turns out that it can suppress.

Although the embodiment of the present invention has been described above, the present invention is not limited to this description and can be appropriately changed without departing from the technical idea of the present invention.
For example, when the plate-like portion is attached to various devices, it is not limited to screwing but may be other fixing means such as a clamp. 2 and 3 are configured to push up the outer peripheral portion of the forged product by the ejector pin, but may be configured to push up the lower end of each pin-shaped fin. Moreover, although neither FIG.2 nor FIG.3 is producing | generating the burr | flash at the time of forging, you may shape | mold by a high pressure with a burr | flash coming out according to the capability of a forging machine. In addition, the initial metal material M in FIG. 2 is a simple plate-like material, but is formed into an appropriate shape in advance from the dimensions of the pin-shaped fins and the size of the cold work applied to the peripheral portion. Also good.

DESCRIPTION OF SYMBOLS 1 Pin-shaped fin integral type heat sink 2 Plate-shaped part 3 Pin-shaped fin 5 Fin standing part 7 Peripheral part 8 Through-hole 9 Central part 11 Mold for fin molding 12 Intermediate molded object 13 Thick part 14 Mold for peripheral part molding DESCRIPTION OF SYMBOLS 15 Fin forming hole 16 Molding die 17 Punch 17a Punch surface 18 Ejector pin 19 Recess 20 Relief 25 Hole 26 Recess 27 Molding die 28 Punch 28a Punch surface 29 Ejector pin 31 Water cooling box 32 Opening 33 Packing accommodation groove 34 Screw Hole 35 Packing

Claims (3)

  It is made of pure copper having a purity of 99.90% by mass or more, and a large number of pin-like fins are erected on one side of the plate-like portion, and at least a part of the peripheral portion of the plate-like portion has a 0.2% yield strength. Is a pin-shaped fin-integrated heat sink characterized in that it is 2 to 5 times the central portion of the plate-like part to which the electronic component is joined.   2. The pin-shaped fin integrated heat sink according to claim 1, wherein the surface roughness of the peripheral edge portion of the plate-like portion is 0.1 μm to 6.3 μm in arithmetic mean roughness Ra.   3. A method for manufacturing a pin-shaped fin-integrated heat sink according to claim 1 or 2, wherein the metal is subjected to a heat treatment of a metal material, and the metal after the heat treatment on a forming die having a large number of fin forming holes. By forging the material, at least a part of the peripheral portion of the plate-like portion is made a thick-walled portion, and the pin-shaped fin and the thin-walled fin are erected on the portion excluding the thick-walled portion A pin-like fin comprising: a hot forging step for forming a standing portion; and a cold forging step for forming a peripheral portion of the plate-like portion by forging the thick portion cold. Manufacturing method of body heat sink.

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