JPS6149346B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a highly thermally conductive composition, and particularly to a highly thermally conductive composition that has a small coefficient of thermal expansion and is suitable for coating semiconductor devices.

(Background of the Invention) In order to avoid instability of characteristics and accelerated deterioration of life of semiconductor elements such as high-output transistors due to heat generation, it is necessary to prevent transistor pellets from rising above the allowable limit temperature. Measures must be taken to do so.

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, measures must be taken to prevent the mounted circuit elements from being affected by external influences, particularly 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 becomes larger and the tendency for circuit elements to become more highly integrated (for example, circuit elements are mounted in the excess space of hybrid integrated circuit devices) increases, heat dissipation becomes more multifaceted. In other words, 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.

The thermal conductivity of these resins is 1.5 to 7.5×10 ^-4 ca
/cm・℃・s (silicone resin), 7~18×
10 ^-4 ca/cm・℃・s (epoxy resin), and its thermal conductivity is inferior not only to metals but also to ceramic insulators such as alumina and beryllia.

For this reason, the current method of using silicone resin or epoxy resin as is as an insulating resin for coating is insufficient to transfer heat in all directions surrounding large-capacity circuit elements and improve the heat dissipation effect. .

Of course, increasing the thermal conductivity of the resin will increase the heat dissipation effect, and conventionally, fillers in which sintered alumina powder, boron nitride sintered powder, etc. are dispersed in the resin have been used. There was something there. However, even when these materials are used, their thermal conductivity is at most about 40×10 ^-4 ca/cm°C sec, and the characteristics of semiconductor devices have not yet been significantly improved.

(Object of the Invention) The present invention was made in view of the above-mentioned situation, and an object of the present invention is to provide a highly thermally conductive composition that can compensate for the drawbacks of conventional coating insulating resins. be.

(Summary of the Invention) The highly thermally conductive composition of the present invention, which achieves the above-mentioned objects, is a powder of a silicon carbide-based sintered body containing silicon carbide as a main component and also containing at least one of beryllium oxide and boron nitride. It is characterized in that the organic polymer material is a silicone resin or an epoxy resin.

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 the focus on its excellent thermal conductivity of /cm・s・℃.

In this way, a composition in which silicon carbide-based sintered powder, which has both excellent electrical insulation and thermal conductivity, is dispersed in silicone-based resin or epoxy-based resin, can be produced by dispersing silicone-based resin or epoxy-based resin itself. It exhibits significantly improved thermal conductivity without any loss in electrical insulation.

(Embodiments of the Invention) The present invention will be described in detail below with reference to the drawings.

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

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
Of course, a value of 10 ¹⁰ Ωcm or more is maintained.

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

Furthermore, when fumed silica is added to the resin composition of the present invention, the spreadability of the resin composition increases;
It can be a suitable insulator when used in the form of a sheet or the like.

Therefore, if the highly thermally conductive composition of the present invention is used as a filler or protective layer material for a semiconductor device, the heat generated in the semiconductor element pellet can be dissipated through the resin composition that has both heat dissipation and insulation properties. It can be transmitted radially, making it possible to enhance the cooling effect.

Hereinafter, the present invention will be explained in more detail using Examples.

Embodiment 1 FIG. 4 is a sectional view of an embodiment in which the present invention is applied to 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.

This rectifier circuit module has a subassembly mounted in a recess provided in an aluminum fin 11, in which four diode pellets 14a, 14b, etc. are electrically connected to form a rectifier circuit, and an insulating resin is mounted in the recess. 16 and 17.

When assembling, first install aluminum fin 1.
An insulator 13 is placed on the bottom surface 12 of the recess provided in 1, and diode pellets 14a and 14a are placed on this insulator.
14b (the other two diode pellets are not shown) is a metal lead 1 that also serves as an electrode and an electrical terminal.
A subassembly integrated with 5a, 15b, and 15c 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 obtained with the above configuration is 8 to 11.
°C/W (average value: 10 °C/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
C/W, number of samples: 200), and it was observed that the heat dissipation of this example was 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.

Embodiment 2 Figure 5 shows a 5KW class for current control, which has four transistor pellets, two diode pellets, two chip resistors, and two chip capacitors mounted on an insulating substrate with an insulator interposed between copper plates. FIG. 2 is a sectional view of an embodiment in which the present invention is applied to a module.

When assembling this current control module, first place the copper mounting plate 2 on the copper support 21 via the insulator 22.
3a and 23b are integrated. The copper mounting plate 23
Circuit elements 28a, 28a, 23b, such as transistor pellets, diode pellets, chip resistors, chip capacitors, etc., are placed on a, 23b.
Equipped with 8b.

Then, predetermined electrical wiring is provided to each circuit element and electrical terminals (not shown) are attached.

Next, the case 24 is attached on the copper support plate 21, and the above-mentioned insulator 22 and the copper mounting plate 2 are attached.
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.

Further, on the first resin composition 25, a second resin composition 26 in which silicon carbide-based sintered body powder with a BN/SiC weight part ratio of 0.03 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 80%, and the volume fraction of the silicon carbide-based sintered body powder in the second resin composition is 80%. It is.

When we attempted to control the output current by applying current equivalent to an input power of 5KW to the current control module obtained with the above configuration, we found that the transistor pellet and diode pellet as the circuit elements mounted on the module The temperature is 90-110℃,
It was possible to maintain an element temperature 15 to 20 degrees Celsius lower than conventional equivalent products using silicone resin and/or epoxy resin in which silicon carbide-based sintered body powder is not dispersed.

Example 3 Figure 6 shows a silicon integrated circuit element pellet placed on a CCB in an alumina package with electrical wiring.
1 is a cross-sectional view of an embodiment in which the present invention is applied to an integrated circuit device mounted by the (Controlled Colaps Bonding) method.

When assembling this integrated circuit device, thick film wiring 32a, 32 provided in the recessed part of the alumina package 31 is used.
A silicon integrated circuit element pellet 34 is mounted on the semiconductor chip 3b via solder balls 33a and 33b.

Then, the space surrounded by the alumina package 31 and the metal cap 35 is filled with 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.
Let it harden.

Further, on the first resin composition 36, a second resin composition 37 in which silicon carbide-based sintered body powder with a BN/BiC weight part ratio of 0.03 is dispersed in an epoxy resin 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%.

When the integrated circuit device obtained with the above configuration was operated by applying a power of 40 W, the temperature of the integrated circuit element pellet mounted thereon did not exceed 100°C.

Although the present invention has been described above with reference to Examples, the present invention is not limited thereto, and the silicon carbide-based sintered body dispersed in silicone-based resin or epoxy-based resin is composed of beryllium oxide and boron nitride. Even if both are included, the effects and advantages of the present invention can be enjoyed.

(Effects of the Invention) As explained above, the resin composition of the present invention maintains electrical insulation and exhibits excellent thermal conductivity, so it can be used as a filler or protective layer of semiconductor devices. By using it as a material, the heat dissipation of the semiconductor device can be improved, and the power capacity and reliability of the device can be increased.

In addition, since the resin composition of the present invention has a small coefficient of thermal expansion, there is little difference in coefficient of thermal expansion from that of the semiconductor material.
It is particularly suitable for coating large semiconductor bodies.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a hybrid integrated circuit device, and FIGS. 2 and 3 are views showing the thermal conductivity of a resin composition that is an example of the present invention, and FIGS. 4, 5, and 6 respectively. 2A and 2B are cross-sectional views showing application examples of the present invention, respectively. 11... Aluminum fin, 12... Bottom of recess, 13... Insulator, 14a, 14b... Diode pellet, 15a to 15c... Metal lead,
16...First resin composition, 17...Second resin composition.

Claims (1)

[Claims] 1. An organic polymer material comprising silicon carbide as a main component and dispersing powder of a silicon carbide-based sintered body containing at least one of beryllium oxide and boron nitride. A highly thermally conductive composition. 2. The highly thermally conductive composition according to claim 1, wherein the organic polymer material is a silicone resin or an epoxy resin. 3. The highly thermally conductive composition according to claim 1 or 2, wherein the content of beryllium oxide and boron nitride in the silicon carbide-based sintered body is 1% or more.