JPS6221249A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the cooling efficiency of semiconductor chips by mixing a diamond powder of high heat conductivity into the insulating gel, thereby reducing the heat resistance. CONSTITUTION:A diamond powder 8 of high heat conductivity is mixed into the insulating gel 9 for preventing the water infiltration to semiconductor chips 1, thereby reducing the heat resistance. Hereupon, the heat generated at chips 1 can be conducted through not only the projected electrodes 2 but also the gel 9, into which the diamond powder 8 is mixed, to a package substrate 6, further to dams 7 and a cap 10 so as to be dissipated. With this, the cooling efficiency of the chips 1 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor device, and particularly to a technique that is effective when applied to a cooling technique for a semiconductor device.

[Background technology]

2. Description of the Related Art In semiconductor devices, in order to obtain large-scale integration, high-density packaging technology in which a plurality of semiconductor chips are mounted on a mounting substrate is sometimes employed.

In such semiconductor devices, in order to prevent the heat generated by the semiconductor chip from affecting the electrical characteristics of the circuit,
Requires cooling means.

As this cooling means, a piston having a spherical part for reliable contact is brought into contact with the semiconductor chip.

A cooling technique has been proposed in which heat generated by the semiconductor chip is released to a cooling medium via a piston or the like.

According to the study of the present inventor, since the semiconductor chip and the spherical portion of the piston are in contact with each other at a point, it is thought that: - Sufficient cooling efficiency may not be obtained.

The cooling technology in which a piston is brought into contact with a semiconductor chip and the heat generated by the semiconductor chip is released to a cooling medium through the piston, etc. is described in 1 Nikkei McGraw-Hill Publishing, "Nikkei Electronics", July 19, 1982 issue, P233～
It is described in P252.

[Purpose of the invention]

An object of the present invention is to provide technical means that can improve the cooling efficiency of a semiconductor device.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

Outline of typical inventions disclosed in this application is as follows.

That is, the cooling efficiency of the semiconductor device is improved by covering at least a portion of the semiconductor chip with a gel mixed with diamond powder having high thermal conductivity.

The configuration of the present invention will be explained below along with examples.

In all the figures, parts having the same functions are denoted by the same reference numerals, and repeated explanations thereof will be omitted.

[Example ■]

FIG. 1 is a sectional view of a main part showing a schematic configuration of Example I of the present invention.

A semiconductor device of Example I is shown in FIG. A silicon semiconductor chip 1 with an integrated circuit formed on its surface is mounted on a wiring board (mother chip) 3 made of silicon single crystal or the like by a flip-chip method, that is, via protruding electrodes 2 on the main surface. . Photo phosphorography technology on wiring board 3.

The wiring having a multilayer structure formed by mask evaporation or the like and the lead 4 are electrically connected by a wire 5. A dam 7 is fixed to a predetermined position of the package substrate 6 with an adhesive such as low-melting point glass, and using the dam 7 as a flow stopper, an electric current mainly composed of silicon mixed with diamond powder 8 having high thermal conductivity is used. It is filled with an insulating gel 9 and surrounds the semiconductor chip 1. The cap 10 is sealed to the dam 7 by fixing it to the dam 7 with an adhesive (not shown) such as low melting point glass. In addition, gel 9 and cap l
There is no need to be in contact with o. In this case, it is desirable to fill in a sealing gas such as an inert gas.

The package substrate 6 is made of a material having high thermal conductivity (2,
7W/CII-K) A sintered body of silicon carbide (SiC) containing a small amount of beryllium (details thereof are shown in JP-A-57-2591) is used.

Note that instead of this, alumina ceramic, glass epoxy, or the like may be used as the substrate 6. As the gel 9 whose main component is silicone, silicone gel is desirable. Since silicone gel is gel-like, it is denatured to absorb mechanical stress caused by differences in coefficients of thermal expansion and the like.

Therefore, gel 9 and chip 1. IT electrode, substrate 3.
Since there is no gap between the wire 5 and the lead 4, no water film is formed in these areas. For this reason 5
The electrode 2 may be damaged due to moisture or contamination that has entered the package.
．． Wire 5. Lead 4. Wiring, etc. will not corrode and cause disconnections, short circuits, etc.

As can be seen from the above description, in this embodiment, diamond powder 8 with high thermal conductivity (20 W/c, , K) is included in the insulating gel 9 to prevent water from entering the semiconductor chip 1. By mixing the diamond powder 8 and reducing the thermal resistance, the heat generated in the semiconductor chip 1 is transferred not only to the protruding electrodes 2 but also to the package substrate 6. Furthermore, dam 7, cap 10
Heat can be radiated by transmitting heat to etc. Thereby, the cooling efficiency of the semiconductor chip 1 can be improved. Note that the value of 20 W/m·K mentioned above is the thermal conductivity of diamond known as type Ua. Since this type na has the highest thermal conductivity, it is desirable to mix it, but it goes without saying that other types of diamonds may also be mixed. This is because the thermal conductivity is higher than that of the substrate 6 in any case.

[Example ■]

The semiconductor device of Example (2) is shown in FIG. Wiring for connection between chips and between chips and leads is directly provided on the package substrate 6.

The semiconductor chip 1 is directly mounted on the package substrate 6 without using the wiring board 3. A small dam 11 is provided to surround the semiconductor chip 1 so that the silicone gel 9 mixed with the diamond powder 8 does not enter into the protruding electrode 2 portion. As a result, a space is partially formed under the main surface of the semiconductor chip l. Gels containing diamonds have higher overall hardness than gels without diamonds. on the other hand.

The electrodes 2 are most likely to be subjected to stress due to heat generated by the operation of the integrated circuit on the semiconductor chip 1. Therefore, in this embodiment, the gel containing diamond is not provided near the electrode 2 to eliminate the possibility of peeling due to thermal stress.

[Example ■]

As shown in FIG. 3, the semiconductor device of Example (2) omits the small dam 11 of the semiconductor device of Example (2), and has at least a protrusion! Silicone gel 9 is covered with an insulating silicone gel 12 up to the point where the ti2 part sinks, and the diamond powder 8 with high thermal conductivity is mixed thereon.
It is covered.

By doing so, the influence of thermal stress on the protruding electrode 2 can be almost ignored.

〔effect〕

As explained above, according to the novel technology disclosed in this application, the following effects can be obtained.

(1) By mixing diamond powder with high thermal conductivity into the insulating gel to prevent water from seeping into semiconductor chips, etc., and reducing thermal resistance, the heat generated in the semiconductor chips can be transferred only to the protruding electrodes. Instead, heat can be radiated by transmitting it to the package substrate through an insulating gel mixed with diamond powder, which has high thermal conductivity. Thereby, the cooling efficiency of the semiconductor device can be improved.

The present invention has been specifically explained above based on examples.
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof.

For example, in the embodiment described above, the present invention is applied to a flip-chip type semiconductor device, but it goes without saying that the present invention can also be applied to a wire bonding type semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part for explaining the schematic structure of Embodiment I of the present invention, FIG. The figure is a sectional view of a main part for explaining the schematic configuration of the embodiment (2) of the present invention. In the figure, 1... semiconductor chip, 2... protruding electrode, 3...
・・Wiring board, 4・Lead, 5・Wire, 6・
...Package substrate, 7...Dam, 8...Diamond with high thermal conductivity, 9...Silicone gel mixed with diamond powder with high thermal conductivity, 10...Cap, 11... Small dam, 12...Silicone gel. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A semiconductor device in which a semiconductor chip is mounted on a substrate, characterized in that at least a portion of the semiconductor chip is covered with an electrically insulating gel mixed with diamond powder. . 2. The protruding electrode portion of the semiconductor chip is covered with a space or an electrically insulating gel, and the other portions are covered with an electrically insulating gel mixed with the diamond powder. semiconductor devices. 3. The semiconductor device according to claim 1, wherein a plurality of the semiconductor chips are mounted. 4. The semiconductor device according to any one of claims 1 to 3, wherein the electrically insulating gel is silicone gel.