JPS6217871B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a high-density LSI (Large Scule Integration)
ation) Regarding package, especially for multiple ICs.
(Integrated Circuit) Pertains to a multi-chip LSI package that can mount chips at high density and has good heat dissipation characteristics.

In recent years, demands for higher performance and smaller computers have been increasing, and as a result, the density of IC chips has increased from a few hundred gates/chip a few years ago to 1000 gates/chip in recent years. It is on the verge of being realized. At the same time, the power consumption per IC chip has improved, and
Devices that consume 4W/chip power are becoming common.

This is because, although the power consumption per gate is decreasing due to an increase in the degree of integration, the power consumption per chip increases slightly due to the increase in the number of gates per chip.

By the way, the conventional LSI package that mounts these IC chips is often a card type, in which a single chip in a case is attached to a printed board by means such as soldering, but recently it has become smaller and has higher performance. Multiple ICs due to demand for
Multi-chip packages, in which chips are mounted on a board using a small case called a chip carrier, and multilayer signal wiring is provided within the board, are coming into use.

The challenges when realizing such a multi-chip package are, firstly, how to mount a large number of IC chips on the package, that is, at high density, and secondly, how to mount these highly integrated chips on the package. The third challenge is to form high-density wiring between multi-terminal IC chips.
The problem lies in how to efficiently dissipate the heat generated by IC chips.

If these issues can be achieved, it will be possible to reduce the size of the multi-chip package, thereby increasing the operating speed by shortening the wiring length, i.e., achieving higher performance, and at the same time achieving higher circuit density.

An object of the present invention is to provide a high-performance, high-density multi-chip LSI package that eliminates the above-mentioned drawbacks, enables efficient heat dissipation, and is miniaturized.

The package of the present invention comprises: a multilayer wiring board having at least one bonding pad; and at least one IC chip having an IC lead connected to the bonding pad, each of which is made of a material with good thermal conductivity;
A plurality of chip carriers each having at least four protrusions on which IC chips are mounted, which are provided at the four corners of the mounting surface and fixed to the multilayer wiring board; It has a plurality of heat sinks provided on a surface opposite to the chip mounting surface, and a holding mechanism that holds each of these heat sinks so as to be fixed to the opposite surface of the chip carrier.

Next, the present invention will be explained in detail with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention includes a multilayer wiring board 8, an input/output terminal 9 attached to the bottom surface of the board 8, and a plurality of IC leads 3 attached to the top surface of the multilayer wiring board 8. IC chips 1, bonding pads 4 provided on the substrate 8 for attaching the IC leads 3 of these IC chips 1, a plurality of chip carriers 2 to which each of these IC chips 1 is attached and attached to the substrate 8, these A heat sink 5 having a heat absorbing body 5-2 positioned in close contact with the chip carrier 2 at one end and a heat dissipating fin 5-1 at the other end, a holding mechanism 7 for holding this heat sink 5,
and a spring 6 inserted between this holding mechanism 7 and the heat absorbing body 5-2 of the heat sink 5.

As the multilayer wiring board 8, it is most preferable to use a green sheet laminated ceramic board, which has recently been widely used and is well known, since multilayer wiring can be accommodated in the inner layer. However, the substrate 8 is not necessarily a green sheet laminated ceramic substrate; for example, it may be a multilayer wiring substrate in which a wiring layer and an insulating layer are formed on a ceramic substrate by a thick film paste printing method. Alternatively, it may be an organic insulating multilayer wiring board in which an organic insulating layer and multilayer wiring layers are formed on a ceramic substrate. That is, no matter what technology the multilayer wiring board 8 is manufactured with, it can be used as the multilayer wiring board 8 constituting the multichip LSI package of the present invention.

Referring to FIG. 2, the chip carrier 2 is
The IC chip 1 is die-bonded to the chip carrier 2 so that the surface on which wiring, transistors, etc. in the IC chip are formed with respect to the multilayer wiring board 8 is placed face down. The IC leads 3 provided around the IC chip 1 are not connected to the chip carrier 2, but are directly bonded to bonding pads 4 on the multilayer wiring board 8. The chip carrier 2 also has protrusions 2-1 at the four corners. This protrusion 2-1 adheres and holds the chip carrier 2 to the multilayer wiring board 8, and also provides space necessary for mechanical protection of the IC chip 1, positioning and mechanical protection of the IC leads 3 between the chip carrier 2 and the multilayer wiring board. 8.

Referring to FIG. 3, the heat sink 5 consists of a heat dissipation fin 5-1, a support post 5-3 to which the heat sink 5-1 is attached, and a heat absorber 5-2. Connected via screws. When connecting with screws, the column 5-3 to which the heat dissipation fin 5-1 is attached is inserted into the heat sink mounting hole 7-1 provided in the holding mechanism 7, and the spring 6 is inserted from below to form a heat absorbing body. 5-2 is screwed. The cross section after this assembly is as shown in Figure 1, and due to the elasticity of the spring 6, the heat absorbing body 5-2
It is devised to ensure that the tip contacts the chip carrier 2. As shown in FIG. 1, the holding mechanism 7 holds a plurality of heat sinks 5, and uses the elasticity of a spring 6 attached to each heat sink 5 to attach the heat absorbing body of the heat sink to each of the chip carriers 2 on the multilayer wiring board 8. are attached to the substrate 8 so as to be in uniform contact with each other. In one embodiment of the present invention, as described above, the heat absorber 5-2
Although we have described an example in which the spring 6 is used to ensure that the heat sink is brought into contact with the chip carrier 2, another example is to provide a female screw tap on the inner wall of the heat sink mounting hole 7-1 and to attach a support post to which the heat dissipation fin 5-1 is attached. Provide a male screw tap around 5-3 and attach the support 5.
- By screwing in 3, the heat absorbing body 5 is heated by the pressure of the screw.
-2 may be brought into contact with the chip carrier 2. Of course, in this case, when screwing in the strut 5-3, the heat absorbing body 5-2 must already be screwed to the support 5-3.

According to the above explanation, the multi-chip according to the present invention
The LSI package brings the following effects.

First, since the leads of the IC chip bonded to the chip carrier are directly bonded to the multilayer wiring board, there is no need to provide wiring inside the chip carrier, and therefore a metal material with good thermal conductivity is used as the material of the chip carrier. This enables effective heat dissipation.

Second, for the same reason as the first, it is possible to downsize the chip carrier and achieve high-density mounting on the board.

Thirdly, since the chip carrier also serves as mechanical protection by covering the chip with its protrusions, the chip can be sufficiently mechanically protected against the contact pressure of the heat absorbing body.

Fourth, due to the first to third characteristics, a large number of
This means that IC chips can be mounted on the board with high density, but in this case, the number of wires connecting between the IC chips increases, but by using a multilayer wiring board for the board, it is possible to increase the density of wiring. A comprehensively high-density LSI package can be realized.

Fifth, because of the second feature, IC chips can be mounted at high density, making it possible to miniaturize the LSI package, and thus also shorten the length of interconnections between IC chips, thereby achieving higher speeds, that is, higher performance.

The present invention realizes a high-density and high-speed multi-chip LSI package by constructing a small chip carrier with good thermal conductivity, a heat sink that can dissipate heat by contacting it, and a multilayer wiring board that can mount small chip carriers at high density. There is an effect that it can be done.

[Brief explanation of the drawing]

1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a detailed configuration of the chip carrier 2 shown in FIG. 1, and FIG. 3 is a diagram showing a detailed configuration of the heat sink 5 shown in FIG. 1. be. In Figures 1 to 3, 1...IC chip, 2...chip carrier, 3...IC lead,
4... Bonding pad, 5... Heat sink, 6... Spring, 7... Holding mechanism, 8... Multilayer wiring board.

Claims (1)

[Scope of Claims] 1. A multilayer wiring board having at least one bonding pad; and at least one IC chip having an IC lead connected to the bonding pad, each of which is made of a material with good thermal conductivity;
A plurality of chip carriers each having at least four protrusions on which IC chips are mounted, which are provided at the four corners of the mounting surface and fixed to the multilayer wiring board; A multi-chip LSI package characterized by having a plurality of heat sinks provided on a surface opposite to a mounting surface, and a holding mechanism that holds each of these heat sinks so as to be fixed to the opposite surface of the chip carrier.