JPH10247698A - Insulating heat dissipating plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat dissipating plate which is high enough in handling properties and mechanical strength and large in thermal conductivity by a method wherein the heat dissipating plate is formed of composite material composed of insulating material such as ceramic formed of alumina, silicon carbide, aluminum nitride (AlN) or the like and a copper plate. SOLUTION: An insulating heat dissipating plate 10 is composed of an insulating layer 11 and a copper plate 12 provided to both its sides or its one side, and a semiconductor device 13 is joined to the one main surface of the plate 10. It is preferable that the insulating layer 11 is as thick (d1 ) as 0.2 to 0.7mm and the copper plates 12 are set as thick (d2 and d3 ) as 0.1 to 0.4mm. If the thickness d1 of the insulating layer 11 is smaller than 0.2mm, it is lessened in mechanical strength and liable to suffer damage in a copper plate bonding process, and if the thickness d1 exceeds 0.7mm, the insulating layer 11 becomes large in heat resistance, so that it deteriorates in heat dissipating properties. Paste which contains active metal such as Ti, Zr, or the like is interposed between the insulating layer 11 and the copper plate 11, whereby the insulating layer 11 and the copper plate 11 are easily bonded together in an atmosphere of inert gas by heating, and an insulating heat dissipating plate 10 of this constitution is not toxic and as high in heat dissipating properties as a conventional BeO-containing heat dissipating plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating heat radiating plate, and more particularly to an insulating heat radiating plate used to increase the heat radiating efficiency of a semiconductor element while insulating a semiconductor element from a substrate constituting a package. .

[0002]

2. Description of the Related Art A semiconductor element such as an integrated circuit is usually mounted on a substrate constituting a package, and is electrically connected to a wiring pattern formed on the substrate by connection means such as wire bonding. Various types of external connection terminals are formed on the substrate, and a wiring pattern formed on the substrate and the external connection terminals are connected to each other via a wiring formed inside the substrate. Have been. When mounting a package including the substrate on which a semiconductor element is mounted on various electronic components, the external connection terminals are connected to connection terminals formed on a motherboard.

When a semiconductor element which generates a large amount of heat during operation with a large capacity is mounted on the substrate, a heat radiation plate is interposed between the semiconductor element and the substrate to generate heat from the semiconductor element. A type that dissipates heat in the horizontal direction to prevent malfunction due to a rise in temperature of the semiconductor element is used. In addition, there are two types of heat radiating plates, one having an insulating property and the other having a conductive property.
When it is not necessary to insulate the semiconductor element and the substrate, for example, a conductive heat sink made of a metal such as Cu or Mo is used, and when it is necessary to insulate the semiconductor element and the substrate, For example, an insulating heat sink having a metallized layer formed on both surfaces of a ceramic layer mainly composed of beryllia (BeO) is used.

An insulating radiator plate using a ceramic layer containing BeO as a main component (hereinafter referred to as a BeO-containing insulating radiator plate) has a very high thermal conductivity and excellent heat radiation characteristics. Due to its own toxicity, it is not preferable to use it from the viewpoint of health care of workers who manufacture heat sinks.
There has been a need for an alternative material to BeO.

[0005]

As the alternative material,
For example, alumina (Al ₂ O ₃ ), silicon carbide (Si
C), ceramics made of aluminum nitride (AlN) and the like. Among these materials, ceramics mainly composed of AlN (hereinafter, also simply referred to as AlN) are non-toxic and ceramics mainly composed of BeO. (Hereinafter, also simply referred to as BeO). However, Al
The thermal conductivity of N is slightly inferior to that of BeO.
Therefore, when manufacturing an insulating heatsink using AlN alone, the thickness must be reduced in order to reduce the thermal resistance value, and the strength of the heatsink manufactured is reduced, resulting in damage. There is a problem that it is difficult to use as a radiator plate because of the difficulty in handling, and a problem in handling.

[0006]

Means for Solving the Problems and Effects Thereof In view of the above problems, the present inventors have studied with the aim of obtaining a radiator plate having no problem in its strength and handleability and having a high thermal conductivity. However, by forming a composite material from an insulating material such as AlN and a copper plate, the strength is improved and the handleability is improved, and furthermore, the present invention has been found to be a radiator plate having a large thermal conductivity. It was completed.

That is, the insulating radiator plate (1) according to the present invention.
Is characterized in that a copper plate is adhered to both sides or one side of an insulating layer in an insulating heat sink in which a semiconductor element is bonded to one main surface.

According to the insulating radiator plate (1), since the copper plate is adhered to the insulating layer, the thermal conductivity is improved, and the strength is further improved by the copper plate, so that the handleability is also improved. This satisfies the required characteristics as an insulating heat sink.

[0009] The insulating heat radiating plate (2) according to the present invention comprises:
In the above insulating radiator plate (1), the insulating layer is made of AlN.
It is characterized by being constituted by ceramics whose main component is.

According to the insulating radiator plate (2), since the insulating layer is made of a ceramic containing AlN as a main component, a paste or the like containing an active metal such as Ti or Zr is applied to the insulating layer. By arranging it between a copper plate and heating in an inert gas, the two can be easily and inexpensively joined together. Compared with the conventional BeO-containing insulating heatsink, it is cheaper and less toxic. In addition, it is possible to provide an insulating heat radiating plate that has little difference in heat radiation characteristics from the BeO-containing insulating heat radiating plate.

[0011] Further, the insulating radiator plate (3) according to the present invention comprises:
In the insulating heat radiating plate (2), the thickness of the insulating layer is 0.2 to 0.7 mm, and the thickness of the copper plate is 0.1 to 0.5 mm.
It is characterized by being 4 mm.

According to the insulating heat radiating plate (3), an insulating heat radiating plate having a thickness not much different from that of the conventional BeO-containing insulating heat radiating plate and having substantially the same heat radiation characteristics as the BeO-containing insulating heat radiating plate is used. Can be provided.

Further, the insulating radiator plate (4) according to the present invention comprises:
In any of the above insulating radiating plates (1) to (3),
It is characterized in that it is interposed between a semiconductor element and a substrate constituting a package.

According to the insulating heat radiating plate (4), since the insulating heat radiating plate is excellent in various characteristics such as heat radiation characteristics, it is interposed between the semiconductor element and the substrate in a power device or the like. This is an optimal member for an insulating heat sink.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the insulating radiator plate according to the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing an insulating radiator plate according to Embodiment (1).

In the central portion of the insulating heat radiating plate 10, resin,
There is an insulating layer 11 made of ceramic or the like, and copper plates 12 are attached to both surfaces of the insulating layer 11.

The constituent material of the insulating layer 11 preferably has a large thermal conductivity as much as possible. Examples of the resin include a heat-resistant resin containing a ceramic having a high thermal conductivity. A ceramic containing AlN as a main component is exemplified. Among these, A
Ceramics containing 1N as a main component have a thermal conductivity of 16%.
Since it is as large as 0 to 200 W / m · K, it has excellent heat dissipation characteristics, and is suitable as a material constituting a heat sink. Further, since the thermal conductivity of the copper plate 12 is about 400 W / m · K, which is much larger than that of 220 to 250 W / m · K of BeO, the copper plate 12 is joined to both surfaces of the insulating layer 11. Thereby, the heat radiation characteristics can be improved, and at the same time, the strength can be increased, and the handling property is improved. If the copper plate 12 has a large thermal conductivity, and if a similar heat radiation property is required, the thickness of the insulating heat radiation plate 10 should be not much different from that of the conventional BeO-containing insulating heat radiation plate. Can be.

For example, the insulating layer 11 mainly composed of AlN
Thickness d ₁ of 0.3 mm and thickness d ₂ (d ₃ ) of copper plate 12
Is 0.15 mm, the total thickness of the insulating radiating plate 10 is 0.6 mm, and the thermal resistance of the insulating radiating plate 10 is about 0.95 ° C./W. The heat radiator having a thickness of 0.635 mm has a thermal resistance of about 0.99 ° C./W, which is not much different from the thermal resistance of the insulating radiator 10. Thus, by combining the insulating layer 11 containing AlN as a main component and the copper plate 12, the insulating radiating plate 10 having substantially the same thickness as the BeO-containing insulating radiating plate and having substantially the same heat radiation characteristics is designed. be able to.

The thickness d ₁ of the insulating layer 11 constituting the insulating heat sink 10 is preferably about 0.2 to 0.7 mm.
2 is preferably about 0.1 to 0.4 mm in thickness d ₂ (d ₃ ). If the thickness d ₁ of the insulating layer 11 is less than 0.2 mm, its strength is reduced and breakage or the like is apt to occur in the step of joining the copper plate 12, while the thickness d ₁ of the insulating layer 11 is 0 mm. When the thickness exceeds 0.7 mm, the thermal resistance increases and the characteristics as a heat sink deteriorate. The thickness d ₂ (d ₃ ) of the copper plate 12
If the thickness is set to less than 0.1 mm, the thickness is too thin and requires a high manufacturing technique, which increases the manufacturing cost, while the thickness d ₂ (d ₃ ) of the copper plate 12 is 0.4
If it exceeds mm, the entire thickness of the insulating heat radiating plate 10 becomes too thick. The thicknesses of the two copper plates 12 may be different from each other.

The composition of the ceramic layer (insulating layer 11) containing AlN as a main component is not particularly limited. For example, an aluminum compound is added to AlN powder as a sintering aid.
AlN produced by adding a calcium compound, an yttrium compound, or the like, and firing at 1600 to 1800 ° C. in a nitrogen atmosphere can be used. Examples of the aluminum compound include Al ₂ O _{3 and the} like, and examples of the calcium compound include CaO, CaCO ₃ and C 2.
Examples of the yttrium compound such as aF ₂ include Y
₂ O ₃ and YF ₃ are exemplified.

Specifically, the sintering aid described above is added to AlN powder,
A binder and a slurry mixed with a plasticizer and the like are formed into a tape shape by a doctor blade method, subjected to a process such as punching, subjected to a degreasing process, and baked under the above-described conditions, and the main component is AlN. Ceramic layer (Al
N plate). The AlN plate to be manufactured preferably has a large area so that a plurality of insulating layers 11 can be formed. Next, a copper plate of the same area is joined to both principal surfaces of the obtained large-area AlN plate to produce a composite for the insulating heat radiating plate 10, and the composite is cut to obtain individual insulating heat radiation. A plate 10 is manufactured.

As a method of joining a copper plate to an AlN plate,
A so-called oxidation treatment method (DBC method) or an active metal method can be used. The DBC method is a method in which an AlN plate having an oxidized surface and an oxygen-containing copper plate are superposed on each other, and then heat-treated in an inert gas.
A method of directly joining a plate and a copper plate. As a preliminary oxidation treatment, the AlN plate was dried at 1150 to 1250 ° C. in dry air.
To form an oxide film on the surface of the AlN plate,
A copper plate containing about 100 to 500 ppm of oxygen
The copper plate is joined to the AlN plate by placing it on a plate and heating at about 1065 to 1083 ° C. for several minutes while flowing a nitrogen gas containing a trace amount of oxygen.

The active metal method is a method in which a paste or a foil containing an active metal such as Ti or Zr is placed between the AlN plate and the copper plate and heated in an argon atmosphere or a vacuum. A method of joining a copper plate to an AlN plate. Specifically, for example, Cu-Ti, Ag-Cu-T
i, paste containing alloy powder such as Ag-Cu-Zr
After applying to both main surfaces of the 1N plate and drying, the binder is removed by heating at 430 to 600 ° C. in an argon or nitrogen atmosphere. Thereafter, the copper plate is placed on the AlN plate and the argon atmosphere is applied. Medium or vacuum, 750-850
The copper plate is joined to the AlN plate by heating at ℃.
For example, Cu-Ti, Ag-Cu-Ti, Ag-Cu-Z
The copper plate may be joined using a foil made of an alloy such as r.

After the above-mentioned joining step is completed, Ni plating processing and Au plating processing are applied to each of the insulating radiating plates 10.
After that, a finishing process such as polishing is performed, and the manufacturing process of the insulating radiator plate 10 is completed. The Ni plating process and the Au plating process may be performed after the finishing process.

The method of bonding the copper plate is less expensive than a method of forming a metallized layer by a vapor phase method such as a sputtering method.
0 can be provided.

The insulating radiator plate 10 on which the semiconductor element 13 is mounted is joined to a substrate such as a ceramic substrate constituting a package, and a pad portion formed on the semiconductor element 13 and a wiring formed on the substrate are connected to each other. Are electrically connected by a method such as wire bonding. The package to which the insulating heat dissipation plate 10 is joined by the above method is mainly used for applications such as power devices.

FIG. 2 is a cross-sectional view schematically showing an insulating heat radiating plate according to the embodiment (2). In this insulating heat radiating plate 20, a copper plate 22 is coated only on the upper surface of an insulating layer 21. Is being worn. As described above, the copper plate 22 may be attached to only one surface of the insulating layer 21 depending on the required thickness and heat radiation characteristics of the insulating heat radiating plate. In FIG. 2, a copper plate 22 is attached on the upper surface of the insulating layer 21,
Conversely, a copper plate 22 may be attached to the lower surface of the insulating layer 21. In this case, since it is necessary to bond the semiconductor element 13 on the insulating layer 21, the semiconductor element 1 of the insulating layer 21
It is necessary to form a metallized layer on the surface where 3 is bonded.

[0029]

EXAMPLES AND COMPARATIVE EXAMPLES Hereinafter, examples of the insulating heat sink according to the present invention will be described. In the present example, the thickness of the insulating layer 11 and the thickness of the copper plate 12 constituting the insulating heat radiating plate 10 (FIG. 1) were changed, and the thermal resistance value was measured. The insulating radiator plate 10 was manufactured by the method described in the above embodiment. As a comparative example, a commercially available BeO-containing insulating radiator plate was used, its thermal resistance was measured, and compared with the thermal resistance of the insulating radiator plate 10 according to the example. Note that the thermal resistance in the present embodiment and the comparative example is the thermal resistance between the semiconductor element 13 and the lower surface of the insulating radiator plate 10.

(1) Insulating radiator plate 10 Insulating layer (ceramic layer mainly composed of AlN) 11 Density: 3.32 g / cm ³ Thermal conductivity: 170 W / m · K Vertical and horizontal dimensions: 7. 22 mm × 7.22 mm Thickness: 0.3 mm, 0.5 mm, 0.635 mm Copper plate 12 Thermal conductivity: 400 W / m · K Vertical and horizontal dimensions: 7.22 mm × 7.22 mm Thickness: 0.05 to Semiconductor element 13 increased in increments of 0.05 mm in the range of 0.35 mm Dimensions: 4.24 mm × 4.24 mm × 0.4 mm (2) BeO-containing insulating radiator Vertical and horizontal dimensions: 7.22 mm × 7.2. 22 mm Thickness: 0.3 mm, 0.5 mm, 0.635 mm (3) Measurement Results and Evaluation of Thermal Resistance FIG. 3 is a graph showing the measurement results of the thermal resistance of the insulating heat sink according to the example and the comparative example. It is. In the graph shown in FIG. 3, the thickness of the insulating radiator plate 10 according to the example is d
₁ (thickness of insulating layer 11) + d ₂ (thickness of copper plate 12) × 2
Becomes Here, the copper plate 1 attached to both surfaces of the insulating layer 11
2 thickness d ₂ and d ₃ is set to the same value.

In the conventional BeO-containing insulating radiator plate, the thermal resistance was measured for three types having thicknesses of 0.3 mm, 0.5 mm, and 0.635 mm. As shown, they were about 0.76 ° C / W, about 0.93 ° C / W, and about 0.99 ° C / W, respectively.

On the other hand, in the insulating radiator plate 10 according to the embodiment, the entire thickness changes depending on the thickness d ₂ (d ₃ ) of the copper plate 12, and the thermal resistance also changes depending on the thickness. Insulation layer 1
1 of a thickness d ₁ and 0.3 mm, when the thickness d ₂ of the copper plate 12 with 0.1 mm, the overall thickness of 0.5mm next insulating heat radiating plate 10, the heat resistance 3 Is about 0.93 ° C./W from the graph of FIG. On the other hand, B having a thickness of 0.5 mm
The thermal resistance of the eO-containing insulating radiator plate is about 0.93 ° C /
W, and both have the same thickness and the same thermal resistance. The thickness d ₁ of the insulating layer 11 is set to 0.3 mm, and the thickness d ₂ of the copper plate 12 is set to 0.15 mm.
The total thickness is 0.6 mm, and the thermal resistance value is about 0.5 mm.
On the other hand, a BeO-containing insulating radiator having a thickness of 0.635 mm has a thermal resistance of about 0.9.
9 ° C./W. In this case, the thickness is also substantially the same and the heat resistance values are substantially the same.

As described above, the insulating layer 1 of the insulating heat radiating plate 10
By using a ceramic layer mainly composed of AlN as 1 and joining copper plates 12 to both main surfaces of the insulating layer 11, the same thermal resistance value as the thickness of the conventional BeO-containing insulating radiator plate and substantially the same ( An insulating radiating plate having heat radiating properties) could be produced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an insulating radiator plate according to Embodiment (1) of the present invention.

FIG. 2 is a cross-sectional view schematically showing an insulating radiator plate according to Embodiment (2).

FIG. 3 is a graph showing the measurement results of the thermal resistance of the insulating heat sink according to the example and the comparative example.

[Description of Signs] 10, 20 Insulating heatsink 11, 21 Insulating layer 12, 22 Copper plate 13 Semiconductor element

Claims (4)

[Claims] 1. An insulating heat radiating plate having a semiconductor element bonded to one principal surface thereof, wherein a copper plate is adhered to both surfaces or one surface of an insulating layer. 2. The insulating radiator plate according to claim 1, wherein said insulating layer is made of a ceramic containing aluminum nitride as a main component. 3. The thickness of the insulating layer is 0.2 to 0.7 mm.
3. The insulating radiator plate according to claim 2, wherein said copper plate has a thickness of 0.1 to 0.4 mm. 4. The insulating heat radiating plate according to claim 1, wherein the insulating radiating plate is interposed between the semiconductor element and a substrate constituting a package.