JPH05109946A - Heat conducting material and its manufacture - Google Patents

Abstract

PURPOSE:To provide a heat conducting material which has good coating properties of a thin film such as plating and a brazing material without a surface fine hole, good matching properties with thermal expansion coefficient of a bonding object material such as a chip and sealing resin, and good heat conducting properties and can set thermal expansion coefficient and heat conduction rate arbitrarily in accordance wit use and purpose by realizing uniformity of heat receiving and thermal diffusion effect. CONSTITUTION:After a copper foil is pressure-welded to both sides of a kovar plate 2 in advance, a three-layer material which is acquired by shaping a number of small holes is pressure-welded to both sides of a copper plate 1 which is heated to a recrystallization temperature or higher by a heating device. Thereby, high junction strength is acquired at a small draft and specified thermal expansion coefficient and heat conduction rate can be acquired without changing a surface area ratio with a copper exposed surface 5 (through-hole) on a surface of the kovar plate 2 which is selected in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention efficiently dissipates heat generated by a semiconductor chip to the outside, such as a heat dissipating substrate for mounting a semiconductor chip or a material for a lead frame. The thermal expansion coefficient and the thermal conductivity are changed arbitrarily so that the matching of the thermal expansion coefficient with the adherend mating material and the good thermal conductivity can both be achieved, and the bondability and surface quality with the mating material are excellent. For heat conductive composite materials, a high thermal expansion metal foil was pressed against both sides of a low thermal expansion metal plate to integrate them, and then a three-layer material with many through holes in the thickness direction was heated to room temperature or recrystallization temperature or higher. By pressing one or both sides of the heated high thermal expansion metal plate, the thermal expansion coefficient, without changing the thickness ratio or through hole area ratio of these metal plates selected with high bonding strength,
The present invention relates to a heat conductive material having a variable heat conductivity, uniform heat reception, improved heat diffusion effect, and excellent adhesion of a thin film such as plating or brazing material without surface fine pores and a manufacturing method thereof.

[0002]

2. Description of the Related Art A semiconductor package integrated circuit chip (hereinafter referred to as a chip), especially an LSI for a large computer
2. Description of the Related Art ULSI and ULSI are advancing toward higher integration and higher calculation speed, and the amount of heat generated is extremely large due to the increase in power consumption during operation. The chip has a large capacity and a large amount of heat generation, and if the coefficient of thermal expansion of the substrate material is largely different from that of the chip material such as silicon or gallium arsenide, there is a problem that the chip peels or cracks.

As a result, semiconductor package design
Since heat dissipation is taken into consideration, the heat dissipation is also required for the substrate on which the chip is mounted, and it is required that the substrate material has high thermal conductivity. Therefore, the substrate is required to have a thermal expansion coefficient close to that of the chip and a high thermal conductivity.

Various structures have been proposed as conventional semiconductor packages, for example, there is a structure in which a radiation fin is attached to a substrate, and a clad plate or C is used to secure heat radiation.
Composite material for heat dissipation substrate such as u-Mo or Cu-W alloy (Japanese Patent Laid-Open Nos. 59-141247 and 62-29).
No. 4147) has been proposed. Although the thermal expansion coefficient and the thermal conductivity of the composite satisfy practical requirements, the composite is heavy and brittle because of high density of Mo, W, etc. Molding has to be performed by plastic working, resulting in high processing cost and poor yield.

In a resin-sealed semiconductor package,
A lead frame made of a copper alloy is often used because the lead frame not only serves as a path for electrical connection to the outside of the chip but also plays an important role as a path for dissipating heat generated in the chip.

However, for applications requiring high reliability, the copper alloy has low mechanical strength, poor matching of thermal expansion coefficient with the chip, and peeling of the adhesive interface between the chip and the island. Therefore, a semiconductor package using a Ni—Fe alloy having a low coefficient of thermal expansion such as 42% Ni—Fe alloy has been proposed in view of the matching of the coefficient of thermal expansion with the chip. However, since the Ni—Fe based alloy has a poor thermal conductivity, it has not been able to obtain heat dissipation enough to meet the current requirements. In addition, the difference in thermal expansion between the chip and the sealing resin is very large, and even if the matching of the thermal expansion coefficient between the lead frame and the chip is good, the matching between the lead frame and the resin is poor and the sealing resin It was difficult to completely prevent the cracks generated in the.

Further, in the ceramics semiconductor package, in order to carry out Al wire bonding and glass sealing, the lead frame often uses a Ni--Fe alloy having Al in the bonding area and sealing position.
However, as described above, the Ni-Fe alloy has a poor heat dissipation property, and there is a problem in matching the coefficient of thermal expansion with ceramics.

[0008] Therefore, in order to solve the above-mentioned problem of the matching of the thermal expansion coefficient and / or the thermal conductivity in the semiconductor package, the applicant has a low thermal expansion metal plate having a required through hole in the thickness direction in the high thermal expansion metal plate. And the high thermal expansion metal foil is pressure-welded to both surfaces of the core material in which the high thermal expansion metal is exposed on the surface of the low thermal expansion metal plate from the through hole, and the thickness ratio and the through hole area ratio of these metal plates are appropriately selected. By
The thermal expansion coefficient and thermal conductivity are variable, uniform heat reception and improvement of thermal diffusion effect are achieved, and there are no surface micropores, and the heat conductive composite material has excellent characteristics such as plating and brazing material adhesion to thin films. Was proposed (Japanese Patent Application No. 2-40550).

[0009]

In order to obtain the above-mentioned heat-conductive composite material, first, a punching process by a press is performed to form a small number of small holes into a mesh shape, and low heat treatment such as Kovar plate wound after annealing is performed. After the expanded metal plate coil is rewound from the upper and lower sides of the high thermal expansion metal plate coil such as a copper plate, it is cold- or warm-rolled by a large-diameter roll and diffusion-annealed to obtain a core material. Further, a high thermal expansion metal foil of Cu, Al or the like unwound from the upper and lower sides of the core material is overlapped, cold- or warm-pressure-bonded by a rolling roll, and diffusion annealing is performed.

In the production of this heat-conductive composite material, a high thermal expansion metal foil such as Cu or Al is superposed on the above core material and cold-pressed. However, if the pressing force is increased to increase the bonding strength, the surface of the core material is increased. The shape of the exposed surface of the high thermal expansion metal such as Cu or Al is changed from a circular shape or an elliptic shape to a long elliptical shape, and the surface area ratio between the selected high thermal expansion metal and low thermal expansion metal is changed to change the thermal expansion coefficient and / or the thermal conductivity. There is a problem that it fluctuates and the coefficient of thermal expansion becomes anisotropic. Further, in the above-described manufacturing process, since the pressing process is repeated twice, the rolling reduction becomes high, which causes the shape of the exposed surface of the high thermal expansion metal to be largely deformed as the spread amount of the core increases.

Therefore, it is conceivable that the surface of the core material is coated with a high thermal expansion metal foil such as Cu or Al by a plating method instead of the above pressure welding method. The plating solution remains at the boundary between the high thermal expansion metal and the low thermal expansion metal on the surface of the material, and this may vaporize during the subsequent diffusion annealing to cause plating swelling or peeling. There is a problem that takes time.

The present invention achieves uniform heat reception and improvement of the heat diffusion effect, has excellent surface adherence to thin films such as plating and brazing materials without surface micropores, and heats the bonding partner materials such as chips and sealing resins. Excellent compatibility with expansion coefficient and good thermal conductivity,
The purpose of the present invention is to provide a heat-conducting material in which the coefficient of thermal expansion and thermal conductivity can be arbitrarily selected according to the application and purpose.Furthermore, when manufacturing this heat-conducting material by pressure welding, the through-hole shape provided in the low thermal expansion metal plate A method for producing a heat-conducting material, which can obtain a selected coefficient of thermal expansion and / or thermal conductivity without making a large change, and can improve the bonding strength between each of the high-thermal-expansion metal and the low-thermal-expansion metal to be laminated. Is intended to be provided.

[0013]

According to the present invention, a high thermal expansion metal foil is pressure-welded to at least the outer surface of one or both surfaces of a high thermal expansion metal sheet heated at room temperature or at a recrystallization temperature or higher, and a large number of penetrations are made in the thickness direction. A low-thermal-expansion metal plate provided with holes is pressure-welded to expose the high-heat-expansion metal from the through hole to the surface of the high-heat-expansion metal foil, and the heat-conducting material is integrated.

Further, according to the present invention, a high thermal expansion metal foil is pressure-contacted with one surface of a low thermal expansion metal plate to be integrated, and then a two-layer material having a large number of through holes in the thickness direction is used at room temperature or at a recrystallization temperature or higher. Of the heat-conducting material, characterized in that the high-thermal-expansion metal plate is exposed to the high-thermal-expansion metal foil surface from the through-hole by press-contacting one side or both sides of the high-heat-expansion metal plate heated to It is a manufacturing method.

Further, according to the present invention, a high thermal expansion metal foil is pressure-bonded to both sides of a low thermal expansion metal plate to integrate them, and then a three-layer material having a large number of through holes in the thickness direction is formed at room temperature or at a recrystallization temperature or higher. The method for producing a heat conductive material is characterized in that one side or both sides of the heated high thermal expansion metal plate are pressed into contact with each other to expose the high thermal expansion metal from the through hole to the surface of the high thermal expansion metal foil and integrate them.

Further, according to the present invention, in the heat conducting material having the above-mentioned constitution, the high thermal expansion metal plate is Cu, Cu alloy, Al,
Any of the Al alloys, the low thermal expansion metal plate is Mo, 3
Ni-Fe based alloy containing 0 to 50 wt% Ni, 25
Ni containing ~ 35 wt% Ni and 4-20 wt% Co
-Co-Fe based alloy, any one of W, and the high thermal expansion metal foil is made of any one of Cu, Cu alloy, Al, Al alloy, and among the heat conductive materials that substantially constitute the five-layer material,
Thickness t ₁ of high thermal expansion metal plate, thickness t of low thermal expansion metal plate
₂ , and the thickness t ₃ of the high thermal expansion metal foil layer satisfies t ₁ = 1t _{2 to} 5t ₂ , t ₃ ≦ 1/10 t ₂ t ₁ + t ₂ = 0.1 to ₃₀ mm, and t ₃ = 2 to 100 μm. Preferably.

Further, according to the present invention, in the heat conductive material having the above-mentioned structure, a metal plating made of any one of Cu, Al, Ni and Sn is deposited on a required position of at least one main surface of the heat conductive material. Is a heat-conducting material. For example, a Ni-Fe alloy, Ni-C, in which a large number of through holes are provided in the thickness direction by press-contacting a high thermal expansion metal foil on one or both surfaces of both main surfaces of a high thermal expansion metal plate such as Cu or Al.
A low thermal expansion metal plate such as an o-Fe alloy is integrated to expose the high thermal expansion metal from the through hole to the surface of the low thermal expansion metal plate, and the metal plating described above is applied to a required position of the outermost high thermal expansion metal foil. Heat-conducting materials for various purposes such as ceramic package, metal package and other chip mounting heat dissipation substrate, lead frame, etc. can be obtained by applying processing such as deposition of brazing material and press molding, lamination etc. ..

[0018]

The heat-conducting material according to the present invention is provided with a large number of through-holes in the thickness direction by pressing a high-thermal-expansion metal foil onto at least the outer surface of one or both surfaces of the high-thermal-expansion metal plate heated to room temperature or above the recrystallization temperature. The low thermal expansion metal plate provided is pressure-contacted, the high thermal expansion metal is exposed from the through hole to the surface of the high thermal expansion metal foil and is integrated, mainly by selecting the thickness ratio of the high thermal expansion metal plate. The coefficient of thermal expansion can be changed arbitrarily, and high thermal conductivity metal is used as the core high thermal expansion metal, and the exposed area of the high thermal expansion metal and the low thermal expansion metal plate fitted in the through hole on the same plane. By appropriately selecting the ratio, the thermal conductivity can be changed arbitrarily,
Material selection and combination of high thermal expansion metal plate and low thermal expansion metal plate,
Also, by selecting the thickness ratio and the exposed area ratio, it is possible to set the thermal expansion coefficient and the thermal conductivity according to various applications and purposes.
A wide variety of heat conducting materials can be provided.

The manufacturing method according to the present invention heats only a simple process of pressing a high thermal expansion metal foil on one surface or both surfaces and a low thermal expansion metal plate having a large number of through holes in the thickness direction. A conductive material can be obtained, and in this case, the shape deformation of the exposed surface of the high thermal expansion metal is small because the pressure welding is performed only once, and the preselected high thermal expansion metal and the low thermal expansion metal plate are exposed on the same plane. It is possible to obtain a heat conductive material having a required coefficient of thermal expansion and thermal conductivity without changing the area ratio. Further, in the manufacturing method according to the present invention, since the high thermal expansion metal foil is pressure-contacted before the low-thermal expansion metal plate is provided with the through-holes, air is blown around the through-holes during pressure contact between the low-thermal expansion metal plate and the high-thermal expansion metal plate. There is little entanglement, the exfoliation of the high thermal expansion metal foil is prevented, and a uniform and excellent outer surface is obtained, so it is not necessary to clad again or plate the high thermal expansion metal foil.

The heat-conducting material according to the present invention has a high thermal expansion coefficient when a high thermal expansion metal sheet is pressed against one side or both sides of the high thermal expansion metal sheet and a low thermal expansion metal sheet having a large number of through holes is formed in the thickness direction. Since the metal plate is heated to the recrystallization temperature or higher, and the high thermal expansion metal materials pressed against the low thermal expansion metal plate are pressed against each other, high pressing strength can be obtained even with a small rolling force. There is little deformation of the through-hole shape, and the predetermined heat amount does not change without changing the exposed area ratio (through-hole area ratio) of the high thermal expansion metal and the low thermal expansion metal plate fitted in the preselected through hole on the same plane. The expansion coefficient and thermal conductivity are obtained. In particular, when the high thermal expansion metal foil is pressed against one surface or both surfaces and the low thermal expansion metal plate having a large number of through-holes in the thickness direction is pressed, the high thermal expansion metal plate is heated to a temperature higher than the recrystallization temperature to reduce a small rolling force. The high thermal expansion metal fits into the through hole of the low thermal expansion metal plate and is exposed on the surface of the high thermal expansion metal foil, and the pressure contact strength is also significantly improved.Furthermore, the high thermal expansion metal foil pressed against the low thermal expansion metal plate and heated high thermal expansion. Combined with the pressure welding effect of the same material of the metal plate, a higher rolling contact strength can be obtained with a smaller rolling force, the rolling rate can be reduced, and the fluctuation of the exposed area ratio can be reduced.
Further, when the high thermal expansion metal exposed on the surface of the high thermal expansion metal foil is the same material, the high thermal expansion metal plate exposed during pressure welding is heated to a temperature higher than the recrystallization temperature, so that it can be integrated with the high thermal expansion metal foil. The surface quality is extremely good.

The heat-conducting material according to the present invention is formed by laminating a low-thermal-expansion metal plate having a high-thermal-expansion metal foil pressed on at least one surface thereof on one or both surfaces of the high-thermal-expansion metal plate. Through holes in the thickness direction are arranged on the entire surface or in a part with a required interval and pattern. For example, the hole size, shape, arrangement pattern, etc. of the through holes are variously changed, or the holes are penetrated or penetrated in consideration of deformation during rolling. By selecting and combining means such as providing a notch, selecting the thickness ratio of the metal plate of the core material and / or the surface area ratio of the high thermal expansion metal and the low thermal expansion metal exposed on the surface of the low thermal expansion metal plate, The thermal expansion coefficient and thermal conductivity can be set for all or part of the material according to the application and purpose. For example, required metals, ceramics, semiconductors such as Si, plastics, etc. Achieving consistency with the thermal expansion coefficient of the counterpart material of the scan or the like, and a material having the required thermal conductivity.

Preferred Embodiment In the present invention, since the high thermal expansion metal plate is press-fitted into the through hole of the low thermal expansion metal plate by pressure welding, it has excellent extensibility of Cu, Cu alloy, Al, Al alloy and the like. It is preferable to use a material having high thermal conductivity. In addition, the low thermal expansion metal plate contains Mo having a ductility and N containing 30 to 50 wt% Ni.
i-Fe alloy, 25-35 wt% Ni, 4-20w
A Ni-Co-Fe based alloy containing t% Co, W or the like can be used. The outermost layer of high thermal expansion metal foil,
Materials such as Cu, Cu alloys, Al, and Al alloys can be selected, and the same or different material as the high thermal expansion metal plate of the core material may be appropriately selected in consideration of the application and the material of the thin film layer to be deposited.

Further, in order to improve brazing property and corrosion resistance, or to improve adherence of Au and Ag plating, Cu, Al, Ni, Sn, etc. are plated, vapor deposited, and ion plated depending on the application. , CVD (che
In addition to depositing by a known coating technique such as medical vapor deposition), solder,
It can be coated with Ag brazing material, ceramics, a glass layer, or the like, or can be applied at a required position.

The through-holes in the thickness direction of the low-thermal-expansion metal plate having the high-thermal-expansion metal foil pressed against the surface can be subjected to mechanical processing such as press punching as well as chemical processing such as etching. Narrower is advantageous in reducing product variations, usually 3 mm or less, preferably 1 mm
Hereafter, it is more preferably 0.5 mm or less, and the through-hole shape has a circular horizontal section, a polygonal shape, etc., and a straight vertical section,
Various shapes such as a taper can be adopted, and in the case of the taper shape, it is possible to facilitate press-fitting into the through hole and increase the bonding strength. Furthermore, the through-holes in the plate thickness direction of the low thermal expansion metal plate may be pressure-contacted and may be the required through-holes to be filled with the high thermal expansion metal plate after rolling, for example, the low thermal expansion metal plate before rolling, the plate thickness Through the required direction or make a cut immediately before the penetration, or by changing the cut direction or the shape of various cuts from both sides of the metal plate, various selections can be made to have the above-mentioned through hole arrangement, The shape of the cut is also −
Various shapes such as + <can be adopted, and wedge-shaped cuts such as triangular pyramids can be formed in the required direction of the plate thickness. Further, in the present invention, the rolling rate is required to be about 60% in the case of cold, but in the case of the present invention, the bond between the high thermal expansion metals is extremely preferable in terms of crystallography and can be reduced to about 20%. A rolling ratio of 30 to 50% is preferable.

Disclosure of the Invention Based on the Drawings The thermal conductive material according to the present invention and the manufacturing method thereof will be described in detail below with reference to the drawings. The heat conductive material of the present invention shown in FIG. 1 is an example in which a copper plate is used as a high thermal expansion metal plate and a Kovar (Fe-Co-Ni alloy) plate is used as a low thermal expansion metal plate. A high thermal expansion metal foil layer 3 is provided on both sides, and a Kovar plate 2 having a large number of through holes 4 in the thickness direction is press-contacted.

In the Kovar plate 2 having the high thermal expansion metal foil layer 3 pressed against both sides of the copper plate 1, through holes 3 of the same size are formed in the thickness direction of the plate, and the circular copper is formed on the high thermal expansion metal foil layer 3. Although the exposed surfaces 5 are arranged, when the high thermal expansion metal foil layer 3 is made of the same copper material, the copper exposed surfaces 5 are diffused and integrated so that they cannot be distinguished. Although the through holes 3 having the same size are formed in the plate thickness direction here, the through holes 3 may be tapered so that the hole sizes are different on the front and back sides, and adjacent holes may be arranged so as to be a combination of large and small hole sizes. it can.

The thickness and copper exposed surface 5 of each Kovar plate 2 pressed against both sides of the copper plate 1 through the high thermal expansion metal foil layer 3.
By selecting the ratio, dispersion state, etc., the thermal characteristics of each principal surface can be approximated to the required characteristics. Further, Cu, Cu alloy, Al, Al, Al, Al are added to the outermost high thermal expansion metal foil layer 3 in consideration of the use and the material of the thin film layer to be adhered.
Since an alloy or the like is selected, uniform heat reception, heat diffusion effect, bondability with the mating material, and improvement of thin film adherence can be obtained.

In order to manufacture a heat conductive material using the above-mentioned copper plate, Kovar plate and copper foil, as shown in FIG. 2, first, a copper foil 6 is pre-pressed onto both surfaces of the Kovar plate 2 having a required size and thickness. After being pressed by 7 and stocked to the required length by a looper device, punching is further performed by a press machine 8. For example, many small holes are punched to form a mesh, and further surface treatment after annealing. And apply it to the coil. It should be noted that, after being pressed by the pressing roll 7, the coil may be once wound around the coil, then rewound and fed to the press machine 8 for processing. Next, as shown in FIG. 3, the copper plate 1 coil having a required size and thickness is rewound, heated to a recrystallization temperature or higher by a heating device 10, and rewound from above and below the punched three-layer material 9, 9 are piled up and pressed against each other by a pressing roll 7.

Since the copper plate 1 is heated above the recrystallization temperature during press contact with the punched three-layer material 9, 9, the copper plate 1 is fitted into the through hole of the Kovar plate 2 with a small reduction force, and the copper of the Kovar plate 2 is cut. The copper foil 6 exposed on the surface of the foil 6 and the copper foil 6 and the copper sheet 1 between the copper sheet 1 and the Kovar plate 2 and the outermost copper foil 6 and the copper sheet 1 are diffused and integrated with each other. Strength is obtained, deformation of the through-hole shape provided in the Kovar plate 2 is small, and thermal expansion does not change without changing the exposed area ratio of the exposed copper plate 1 and Kovar plate 2 on the surface of the Kovar plate 2 selected in advance. The desired coefficient of thermal expansion and thermal conductivity can be obtained without the occurrence of directionality.

In the above pressure welding, the heating atmosphere and the pressure welding atmosphere of the high thermal expansion metal material are preferably non-oxidizing atmospheres, such as N ₂ , Ar, H ₂ or a mixed gas atmosphere thereof, ammonia decomposition gas, propane combustion. Gas (DX)
Gas or the like can be used. Further, the heating device is appropriately selected according to the material of the high thermal expansion metal material used, but a tubular furnace, a light beam heating device, a laser heating device, a high frequency heating device, a plasma heating device or the like can be adopted. The heating temperature of the high thermal expansion metal material is appropriately selected from the temperature range above the recrystallization temperature of the selected material and below the melting point, but a temperature lower than the melting point by about 100 ° C. and below the melting point is preferable, copper,
The temperature is 950 to 1050 ° C. in the case of copper alloy material, 550 to 650 ° C. in the case of Al and Al alloy materials, and 800 to 900 ° C. in the case of Ag and Ag alloy materials.

Further, as shown in FIG. 4, instead of the punched three-layer material 9 in which the copper foils 6 are pressure-welded to both sides of the Kovar plate 2, as shown in FIG.
After the copper foil 6 is pressed against the upper surface of the Kovar plate 2 by the pressing roll 7 and the required length is stocked by the looper device,
The punching process is performed by the press machine 8, and the obtained punched two-layer material 11 is brought into contact with the Kovar plate 2 of the punched two-layer material 11 on both sides of the copper plate 1 heated to the recrystallization temperature or higher, as in FIG. Then, pressure contact is performed, and the heat conductive material according to the present invention can be manufactured. It should be noted that, after being pressed by the pressing roll 7, the coil may be once wound around the coil, then rewound and fed to the press machine 8 for processing. The above-mentioned heat-conducting material using the punched two-layer material 11 press-contacts the Kovar plate 2 on both surfaces of the copper plate 1, and therefore has the same pressure contact strength as that using the three-layer material 9 for pressure-contacting copper materials. In order to obtain the above, it is desirable to perform low temperature annealing after pressure welding. Further, since the outermost copper foil 6 of the heat conductive material is pressed against the Kovar plate 2 in advance, the advantage that there are few defects such as peeling is that the material is punched 3 layer material 9, punched 2
The same applies regardless of which of the layer materials 11 is used.

[0032]

EXAMPLES Example 1 Kovar plate (29N with a thickness of 0.5 mm and a width of 30 mm)
(i-16Co-Fe alloy) is annealed at 900 ° C. and wire brushing is performed, and then a Cu foil having a thickness of 0.2 mm and a width of 30 mm is pressed onto one surface of the Cu foil to obtain a Cu foil thickness of 60 μm.
m, total thickness 0.28 mm, not a two-layer material, pore diameter 1.0 m
m, rolling direction hole spacing 2.0 mm, width direction hole spacing 2.0 m
Multiple perforations were made in m. In addition, 30 to 2 of Kovar plate
The average coefficient of thermal expansion at 00 ° C is 5.2 × 10 ^-6 /
Was ° C.

Cu with a plate thickness of 0.35 mm and a plate width of 30 mm
After wire brushing the plate, heat to 900 ° C,
The Cu plate is pressed against the Kovar surface side of the two-layer material by a press-contacting machine, copper penetrates into the through holes of the Cu / Kovar composite plate, and the copper plate surface is partially located at the required position of the outermost copper foil. A three-layer material having a plate thickness of 0.25 mm and exposed and integrated was obtained. The rolling rate was 60%. The Cu exposed surface on the main surface of the obtained heat conductive material was substantially circular in the rolling direction, the hole interval was 2.0 mm in the rolling direction, and the ratio of the Cu exposed surface to the Kovar plate was 35%. Cu plate 30 to 200 ° C
The average coefficient of thermal expansion was 17.2 × 10 ⁻⁶ / ° C. The thermal conductivity of the obtained material in the thickness direction is 250 w /
m · K and coefficient of thermal expansion on each main surface is 9 × 10 ⁻⁶ /
It was ℃.

Example 2 Kovar plate (29N, thickness: 0.5 mm, width: 30 mm)
(i-16Co-Fe alloy) is annealed at 900 ° C. and wire brushed, and then 0.2 mm thick on one side, 0.05 mm thick on the other side, and a Cu foil having a width of 30 mm is pressure-welded to the Cu foil to a thickness of 30 μm. Three-layer material with a total thickness of 0.29 mm, hole diameter 1.0 mm, hole spacing in the rolling direction 2.0 m
m, and a number of perforations were made at a hole interval in the width direction of 2.0 mm.

Cu having a thickness of 0.35 mm and a width of 30 mm
After wire brushing the plate, heat to 900 ° C,
The Cu plate is pressed against the thin Cu side surface of the three-layer material by a pressure welding machine, copper penetrates into the through holes of the Cu / Kovar composite plate, and the copper plate surface is placed at the required position of the outermost copper foil. A partially exposed and integrated three-layer material having a plate thickness of 0.25 mm was obtained. The rolling rate was 62%. The exposed Cu surface on the main surface of the obtained heat conductive material was substantially circular in the rolling direction, and the hole spacing was 2.0 mm in the rolling direction.
The ratio of the u exposed surface was 35%. The thermal conductivity of the obtained material in the thickness direction was 250 w / m · K, and the thermal expansion coefficient on each main surface was 9 × 10 ⁻⁶ / ° C.

Example 3 Kovar plate (29N, thickness 0.3 mm, width 30 mm)
i-16Co-Fe alloy) is annealed at 900 ° C and wire brushed, and then 0.05 mm on both sides.
A Cu foil with a thickness width of 30 mm is pressure-welded to a Cu foil thickness of 30 μ.
m, with a total thickness of 0.25 mm and a three-layer material, pore diameter 1.0 m
m, rolling direction hole spacing 2.0 mm, width direction hole spacing 2.0 m
Multiple perforations were made in m.

A Cu plate having a plate thickness of 0.5 mm and a plate width of 30 mm was wire-brushed and then heated to 800 ° C., and the both surfaces of the Cu layer were pressed by a pressure welding machine as shown in FIG. Copper penetrated into the through-holes, and the surface of the copper plate was partially exposed at a required position of the outermost copper foil to obtain a three-layer material having a plate thickness of 0.4 mm 2. The rolling rate was 60%. The exposed Cu surface of the main surface of the obtained heat conductive material was substantially circular in the rolling direction, and the hole spacing was 2.0 mm in the rolling direction.
And the ratio of the exposed Cu surface to the Kovar plate is 35%.
Met. The thermal conductivity of the obtained material in the thickness direction is 230.
w / m · K and coefficient of thermal expansion on each major surface is 8 × 10
It was ^-6 / ° C. In this heat conductive material, the thickness of the Cu plate (t ₁ ) is 0.15 mm, the thickness of the Kovar plate (t ₂ ) is 0.115 mm, and the thickness of the Cu foil on the surface (t ₃ ) is 0.01 mm. (See FIG. 1).

A heat conductive material having a plate thickness of 0.4 mm was cut into a required size, and two sheets were laminated to form a heat dissipation board. When a ceramic package was manufactured using the heat dissipation substrate, it was confirmed that good heat dissipation was obtained and thermal compatibility was also excellent.

Further, a heat conductive material having a plate thickness of 0.4 mm
After annealing at 000 ° C. for 5 minutes in a hydrogen atmosphere, cold rolling was performed to a plate thickness of 0.15 mm. In the obtained heat conductive material, the thickness (t ₁ ) of the Cu plate constituting the core material is 0.068.
mm, the thickness (t ₂ ) of the Kovar plate is 0.038, respectively.
mm, surface Cu foil thickness (t ₃ ) is 0.00
It was 3 mm. After that, when processed into a lead frame by a known method to manufacture a semiconductor package, peeling of the adhesive interface between the chip and the island and cracks of the sealing resin did not occur, and the conventional copper alloy was used. Good heat dissipation was obtained, which is close to that of conventional lead frames.

[0040]

EFFECTS OF THE INVENTION The heat conducting material according to the present invention is a three-layer material or a two-layer material in which a high thermal expansion metal foil is pressed against both surfaces or one surface of a low thermal expansion metal plate to be integrated, and then a large number of through holes are provided in the thickness direction. The layered material is bonded to one surface or both surfaces of a high thermal expansion metal plate heated at room temperature or at a recrystallization temperature or higher by pressure-bonding to expose the high thermal expansion metal from the through hole to the surface of the high thermal expansion metal foil to integrate the bonding strength. The thermal expansion coefficient and the thermal conductivity can be arbitrarily changed without changing the thickness ratio and the through hole area ratio of the selected metal plates, and the metal, the ceramics, the semiconductor such as Si, the plastic, etc. Thin film such as plating or brazing material without surface micropores, which can achieve both good thermal conductivity and good thermal expansion coefficient matching with other material to be adhered, uniform heat reception, and improved heat diffusion effect. Adhesion of Are, the optimal heat transfer material to the radiating substrate and the material for the lead frame for semiconductor chip mounting. Further, since the pressure contact, which is a factor of the variation of the thickness ratio of the metal plate and the through hole area ratio, is only required once, the process is simplified and the heat conductive material can be provided at a low cost.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a heat conductive material according to the present invention.

FIG. 2 is a perspective explanatory view showing an example of equipment for manufacturing a heat conductive material according to the present invention.

FIG. 3 is a perspective explanatory view showing an example of equipment for manufacturing the heat conductive material according to the present invention.

FIG. 4 is a perspective explanatory view showing an example of equipment for manufacturing another heat conductive material according to the present invention.

[Explanation of symbols]

 1 Copper Plate 2 Kovar Plate 3 High Thermal Expansion Metal Foil Layer 4 Through Hole 5 Copper Exposed Surface 6 Copper Foil 7 Pressing Roll 8 Press Machine 9 Punching 3 Layer Material 10 Heating Device 11 Punching 2 Layer Material

Claims (3)

[Claims] 1. A low thermal expansion metal plate in which a high thermal expansion metal foil is pressure-welded to at least the outer surface of one or both surfaces of the high thermal expansion metal plate heated at room temperature or at a temperature higher than the recrystallization temperature to provide a large number of through holes in the thickness direction. Is heat-welded to expose the high thermal expansion metal from the through hole to the surface of the high thermal expansion metal foil to be integrated therewith. 2. A high heat treatment method comprising heating a high thermal expansion metal foil on one surface of a low thermal expansion metal plate under pressure to integrate the two layers and then heating a two-layer material having a large number of through holes in the thickness direction to room temperature or a recrystallization temperature or higher. A method for producing a heat conductive material, characterized in that one side or both sides of an expanded metal plate are pressed against the low thermal expansion metal plate side to expose the high thermal expansion metal from the through hole to the surface of the high thermal expansion metal foil and integrate them. 3. A three-layered material having a high thermal expansion metal foil pressure-bonded to both sides of a low thermal expansion metal plate and integrated with it, and then a three-layer material having a large number of through holes in the thickness direction, heated at room temperature or at a recrystallization temperature or higher. A method for producing a heat-conducting material, comprising press-contacting one surface or both surfaces of an expanded metal plate, exposing the high thermal expansion metal from the through hole to the surface of the high thermal expansion metal foil, and integrating them.