JPS6115901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a structure that effectively dissipates heat generated in a semiconductor pellet.

In a hybrid integrated circuit device equipped with a plurality of high-output transistors, which is an example of a semiconductor device, a collector current of several amperes or more flows. At this time, the transistor pellet as a semiconductor element usually generates heat.

In order to avoid instability of characteristics and accelerated deterioration of lifetime due to heat generation, a method must be taken to prevent the temperature of the transistor pellet from rising beyond the permissible limit temperature.

In addition, in order for a hybrid integrated circuit device to have a predetermined electrical function, the circuit elements mounted on the circuit device, especially transistor pellets as semiconductor elements, must be electrically insulated from other circuit elements. In many cases, this is not the case.

Furthermore, in hybrid integrated circuit devices that require advanced functionality, the mounted circuit elements are subject to external influences.
In particular, measures must be taken to avoid electromagnetic interference.

As an example of a hybrid integrated circuit device that satisfies the above requirements, as shown in FIG. Circuit elements such as semiconductor elements 3 and 3' as well as resistors and capacitors are mounted using solders 4 and 4', and predetermined electrical wiring is provided to each circuit element, and at the same time, predetermined electrical terminals are provided (electrical There is a device having a structure in which wiring and terminals (not shown) are coated with an insulating resin 6.

In such a semiconductor device, various measures have been taken so that the heat generated in the circuit elements is mainly released to the outside via the insulators 2, 2' and the metal support 1.

On the other hand, as the capacity of hybrid integrated circuit devices increases and the tendency to increase the integration of circuit elements (e.g., mounting circuit elements in the excess space of hybrid integrated circuit devices) increases, heat dissipation becomes multifaceted. There is an increasing need to dissipate heat not only from the heat flow path from the circuit element to the metal support via the insulator, but also from the top or side surface of the hybrid integrated circuit device via the insulating resin for molding.

Insulating resins conventionally used for coating are often silicone resins or epoxy resins, but the thermal conductivity of these resins is 1.5 to 7.5 × 10 ^-4 cal/
cm・℃・s (silicone resin), 7 to 18×10 ^-4 cal/
cm・℃・s (epoxy resin), its thermal conductivity is inferior not only to metals but also to ceramic insulators such as alumina and beryllia.

Therefore, in order to transfer heat in all directions surrounding large-capacity circuit elements and increase the heat dissipation effect, it is necessary to
The current method of using silicone resin or epoxy resin as is as the insulating resin for coating is insufficient.

Of course, increasing the thermal conductivity of the resin increases the heat dissipation effect, and in the past, fillers such as alumina sintered powder or boron nitride sintered powder have been dispersed in the resin. Some were. However, even when these materials are used, their thermal conductivity is at most about 40×10 ^-4 cal/cm°C sec, and the characteristics of semiconductor devices have not yet been significantly improved.

The present invention has been made in view of the above-mentioned situation, and it is an object of the present invention to provide a semiconductor device that compensates for the drawbacks of the conventional insulating resin for coating and has good heat dissipation.

The semiconductor device of the present invention that achieves the above-mentioned object comprises a silicone resin or an epoxy resin;
Filling with a highly thermally conductive composition that is dispersed in the silicone resin or epoxy resin and is composed of silicon carbide as a main component and sintered powder containing at least one of perylium oxide and boron nitride. It is characterized by being included as an object or a protected object.

That is, in the present invention, when the content of beryllium oxide and boron nitride contained in silicon carbide powder is 2 parts by weight or more with respect to 100 parts by weight of silicon carbide,
The silicon carbide-based sintered body exhibits good electrical insulation with a specific resistance of 10 ¹⁰ Ωcm or more, and a thermal conductivity of 0.7ca.
This was developed with an eye to its excellent thermal conductivity of l/cm・s・℃.

In this way, a composition in which silicon carbide powder, which has both excellent electrical insulation and thermal conductivity, is dispersed in silicone resin or epoxy resin has better electrical insulation than silicone resin or epoxy resin itself. It exhibits significantly improved thermal conductivity without any loss in performance.

FIG. 2 shows the relationship between the volume fraction of silicon carbide (horizontal axis) and thermal conductivity (vertical axis) in a composition in which silicon carbide-based sintered body powder is dispersed in silicone-based resin. Thermal conductivity tends to increase significantly as the volume fraction of the silicon carbide sintered body increases.

This shows that the resin composition described above is extremely useful for improving the heat dissipation properties of semiconductor devices.

Further, FIG. 3 shows the relationship between the volume fraction of silicon carbide-based sintered body and thermal conductivity of a composition in which silicon carbide-based sintered body powder is dispersed in epoxy-based resin. In this case as well, it can be seen that the thermal conductivity increases significantly as the volume fraction of the silicon carbide-based sintered body increases. At this time, the specific resistance of the resin composition is 10 ¹⁰ Ωcm
Of course, the above values are held.

The reason why the aforementioned resin composition has excellent heat dissipation properties is that the disadvantages of silicone resins or epoxy resins, which inherently have low thermal conductivity, are compensated for by the silicon carbide sintered powder dispersed in these resins. This is because it is possible.

Further, when fumed silica is added to the resin composition of the present invention, the spreadability of the resin composition increases, so that it can become a suitable insulator when used in the form of a sheet or the like. Therefore, if the highly thermally conductive composition is used as a filler or protective layer material for the semiconductor device of the present invention, the heat generated in the semiconductor element pellet can be transmitted radially through the resin composition that has both heat dissipation and insulation properties. Therefore, it becomes possible to enhance the cooling effect.

Hereinafter, the semiconductor device of the present invention will be explained in more detail using examples.

Example 1 This example is a 5A class rectifier circuit module in which four diode pellets are mounted on an aluminum fin that serves both as a storage container for semiconductor elements and as a heat sink.

As shown in FIGS. 4a and 4b, this rectifier circuit module has four diode pellets 14a, 14b...
... are mounted with electrically connected subassemblies so as to constitute a rectifier circuit, and the recesses are filled with insulating resins 16 and 17.

At this time, the diode pellet mounting part is
To explain this using an arbitrary cross-sectional view shown in FIG. (two pellets are not shown) and metal leads 15a, 15b, 15c that also serve as electrodes and electrical terminals.
A sub-assembly integrated with is placed.

Then, around these insulators 13 and sub-assemblies, silicone resin is coated with BeO/SiC.
A first resin composition 16 in which silicon carbide-based sintered body powder containing a weight part ratio of 0.02 is dispersed is filled and cured. Further, on the first resin composition 16, a second resin composition 17 in which silicon carbide-based sintered body powder containing a BeO/SiC weight part ratio of 0.02 is dispersed in an epoxy resin is filled and cured.

The volume fraction of the silicon carbide-based sintered body powder in the first resin composition described above is 71%, and the volume fraction of the silicon carbide-based sintered body powder in the second resin composition is 70%. It is.

The thermal resistance between the diode pellet and air of the rectifier circuit module of this embodiment obtained with the above configuration is as follows:
8 to 11℃/W (average value: 10℃/W, number of samples: 200
). On the other hand, the thermal resistance of conventional equivalent products using silicone resin and epoxy resin without dispersing silicon carbide sintered body powder is 13 to 15℃/W (average value: 14℃/W, number of samples: 200). It was found that the heat dissipation properties of this example were significantly improved compared to the conventional example. As a result, it has become possible to increase the allowable current capacity of the rectifier circuit module from the conventional 5A to 6A.

Example 2 This example is a 5KW class for current control, which is equipped with 4 transistor pellets, 2 diode pellets, 2 chip resistors, and 2 chip capacitors on an insulating substrate with an insulator interposed between copper plates. It is modular.

The structure and manufacturing method of this current control module are explained in the fifth section.
To explain using an arbitrary cross-sectional view shown in the figure, first, copper mounting plates 23a and 23b are integrated on a copper support 21 with an insulator 22 interposed therebetween. Said copper mounting plate 2
On the circuit elements 3a and 23b, circuit elements 28a, such as transistor pellets, diode pellets, chip resistors, chip capacitors, etc., are arranged as the circuit elements described above.
Equipped with 28b. Then, predetermined electrical wiring is provided to each circuit element and electrical terminals (not shown) are attached.

Further, the case 24 is attached on the copper support plate 21, and the above-mentioned insulator 22 and the copper mounting plate 2 are mounted on the copper support plate 21.
1. Transistor pellets, diode pellets, chip resistors as circuit elements 28a and 28b,
A first resin composition 25 in which silicon carbide-based sintered body powder with a BN/SiC weight part ratio of 0.03 is dispersed in a silicone-based resin so as to completely surround a chip capacitor.
Fill and harden. Furthermore, the first resin composition 2
On top of 5, add BN/SiC weight part ratio 0.03 to epoxy resin.
A second resin composition 26 in which silicon carbide-based sintered body powder is dispersed is filled and cured.

The volume fraction of the silicon carbide-based sintered body powder in the first resin composition described above is 80%, and the volume fraction of the silicon carbide-based sintered body powder in the second resin composition is 80%. It is.

The current control module of this example obtained with the above configuration was energized with an input power of 5KW, and
When we tried to control the output current, the temperature of the transistor pellet and diode pellet, which are the circuit elements mounted on the module, was 90 to 110 degrees Celsius.
Therefore, the device temperature could be maintained 15 to 20°C lower than a conventional equivalent product using silicone resin and/or epoxy resin in which silicon carbide-based sintered body powder is not dispersed.

Example 3 In this example, silicon integrated circuit element pellets are placed on a CCB in an alumina package with electrical wiring.
This is an integrated circuit device mounted using the (Controlled Colaps Bonding) method.

In this integrated circuit device, as shown in FIG.
Solder balls 33a, 33b are placed on the thick film wirings 32a, 32b provided in the recessed part of the alumina package 31.
A silicon integrated circuit element pellet 34 is mounted thereon. Then, in the space surrounded by the alumina package 31 and the metal cap 35, a first resin composition 36 in which silicon carbide-based sintered body powder with a BeO/SiC weight part ratio of 0.03 is dispersed in a silicone-based resin is applied.
Fill and harden. Furthermore, the first resin composition 3
On top of 6, add BN/SiC weight part ratio 0.03 to epoxy resin.
A second resin composition 37 in which silicon carbide-based sintered body powder is dispersed is filled and cured. 35 is a metal cap.

The volume fraction of the silicon carbide-based sintered body powder in the first resin composition 36 described above is 80%, and the volume fraction of the silicon carbide-based sintered body powder in the second resin composition 37 is 80%. It is 80%.

The integrated circuit device of this example obtained with the above configuration
When the device was operated by applying 40W of power, the temperature of the integrated circuit element pellet mounted on it did not exceed 100℃.

Although the present invention has been described above with reference to examples, the present invention is not limited to these examples, and the effects and advantages of the present invention can be enjoyed even in the following cases.

(1) When the silicon carbide sintered body dispersed in silicone resin or epoxy resin contains both beryllium oxide and boron nitride.

(2) It is not necessary to directly coat semiconductor element pellets with a resin composition; for example, as shown in FIG. It is also effective when fixing via an object. In FIG. 7, 41 is a semiconductor device, and 42 is a thin film formed from the above-mentioned resin composition.

The resin composition described above exhibits excellent thermal conductivity while maintaining electrical insulation properties, so by using this resin composition as a filler or protective layer material, the heat dissipation properties of semiconductor devices can be improved. , the power capacity and reliability of the device can be increased.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of a hybrid integrated circuit device, Figures 2 and 3
The figures each show the thermal conductivity of a resin composition suitable for the present invention, Figures 4a and 4b and Figures 5 and 6 are perspective views and sectional views respectively showing examples of the present invention, and Figure 7 is a diagram showing the thermal conductivity of a resin composition suitable for the present invention. It is a side view which shows the modification of this invention. 11... Aluminum fin, 12... Bottom of recess, 13... Insulator, 14a, 14b... Diode pellet, 15a, 15c... Metal lead,
16...First resin composition, 17...Second resin composition.

Claims (1)

[Claims] 1. A semiconductor device including a semiconductor pellet whose outer periphery is at least partially covered with an insulating material,
The insulating material mainly contains silicon carbide and also contains at least one of beryllium oxide and boron nitride.
A semiconductor device characterized in that it is a highly thermally conductive composition made of an organic polymer material in which a powder of a silicon carbide-based sintered body containing seeds is dispersed. 2. The semiconductor device according to claim 1, wherein the organic polymer material is a silicone resin or an epoxy resin.