JPS614255A - Package for integrated circuit - Google Patents

Abstract

PURPOSE:To improve heat conducting characteristics from an IC chip to a heat sink, by inserting heat connectors, in which heat conducting fiber is implanted in resilient sheets, between chip carriers and the heat sink under the compressed state. CONSTITUTION:Many chip carriers 3 are connected and arranged on a wiring substrate 1 through a solder bonding part 2. Heat connectors 5, in which heat conducting fiber is implanted in resilient sheets, are inserted between the chip carriers 3 and a heat sink 4 under the state the heat conducting fiber is compressed to the degree the fiber is bent. The heat conductor 5 is formed by embedding many beryllium copper thin wires 18, which are the conducting fiber, in silicone rubber 17, which is a relatively soft insulating material. The connector form an excellent heat conducting path between a chip carrier cap 16 and the heat sink 4. Since the heat sink 4 and the chip carriers 3 are not fixed, stress of expansion and contraction due to temperature difference is not applied between the chip carriers 3 and the wiring substrate 1. Therefore, the connection of the chip carriers 3 and the wiring substrate 1 can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a high-density integrated circuit/mother package, and particularly to an integrated circuit package suitable for mounting a plurality of IC chips at high density.

[Prior art]

In recent years, significant improvements have been made toward higher performance and higher density computers. This is largely due to the progress of LC Chizzo's high integration technology, and the density of high-speed logic circuit IC chips has increased from a few hundred gates/chip a few years ago to 1000-2000 gates/chip in recent years.
Even Chituzo's work has come to fruition. High integration of IC chips requires improvements in microfabrication technology that allows active and passive elements to be formed at high density on a silicon substrate and connections between these elements with fine wiring, as well as improvements in process technology for forming these elements. f-), it can be said that this has been achieved by reducing power consumption.

However, with the realization of such high integration.

The power consumption of high-speed logic circuit chips tends to be higher than in the past. The reason for this is.

This was a natural attempt by design engineers to minimize the signal propagation speed and drive energy consumed by the wiring f by shortening the length of the connection wiring between the shear dirt circuits as much as possible by increasing the density of the dirt circuits. It is. Therefore, in the package structure in which these IC chips are mounted,
An important technical issue is how to effectively dissipate the heat generated by high-power IC chips. One of these technologies
An example can be found in JP-A-57-134953. That is, according to the embodiment, the heat generated by the IC chip is transmitted to the heat sink through a preform made of fiber glass and thermosetting plastic resin, and is dissipated. However, the thermal conductivity of such plastic resins is 0.005 w/in.
It is on the order of °C.

-1 point worse than inorganic materials. For example, the thermal conductivity of metal oxides such as alumina is on the order of 0.7 W/in.°C, and for metals such as copper is on the order of 10 W/in.°C. Therefore, in the case of such a structure, the limit of the cooling capacity of the IC chip is determined by the thermal conductivity characteristics of the plastic resin, and the limit of the cooling capacity of the IC chip is determined from both the side thermal characteristics of the IC chip and the mechanical stress of expansion and contraction due to the temperature difference of the heat sink. This makes it difficult to mount an IC chip that consumes a lot of power, that is, generates a lot of heat.

[Purpose of the invention]

Therefore, it is an object of the present invention to improve the heat conduction characteristics from the IC chip to the heat sink, and to also alleviate the mechanical stress caused by thermal expansion and contraction due to the temperature difference between the wiring board on which the IC chip is mounted and the heat sink. Our goal is to provide integrated circuits and motherboards.

[Structure of the invention]

According to the present invention, a plurality of chip carriers for accommodating IC chips bonded to the inner upper surface thereof are provided on a wiring board, and a heat sink is arranged on the upper part to dissipate heat generated from the IC chips. In the structure, an integrated circuit package is obtained, characterized in that a thermal connector having a structure in which thermally conductive fibers are embedded in a sheet having elasticity is inserted between the chip carrier and the heat sink under pressure.

Next, a detailed explanation will be given with reference to the drawings.

The following margins [Example] FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, in which a large number of chip carriers 3 are connected and arranged on a wiring board 1 via Hirata adhesive parts 2. Between the chip carrier 3 and the heat sink 4, there is a thermal connector 5 having a structure in which thermally conductive barrel fibers are embedded in an elastic sheet, as shown in the figure, and the thermal connector 5 is pressed to the extent that the thermally conductive fibers are slightly bent. It has been inserted in the same state.

FIG. 2 is a partially enlarged view of FIG. I
The C lead 12 is connected to a chip carrier substrate 14 via a bending/-P lead 13, and the main body is bonded to a chip carrier cap 16 with a thermally conductive chip adhesive 15 (for example, silver-filled adhesive). There is. The chip carrier cap 16 is made of a material having particularly good thermal conductivity, such as Bed.

The thermal connector 5 inserted between the chip carrier cap 16 and the heat sink 4 is made of silicon rubber 17, which is a relatively flexible insulator, and beryllium copper thin wire 1, which is a thermal conductive fiber.
8, and constitutes a good heat conduction path between the chip carrier cap 16 and the heat tank 4. In the figure, some of the beryllium copper thin wires 18 are bent and others remain curved, but this is merely a model to show that there are various states; when released, all the thin wires become almost vertical. It is suitable for Therefore, the heat generated by the IC chip 11 is transferred to the chip adhesive 15, the chip carrier cap 16. The heat is dissipated through the path of the heat connector 5 and the heat sink 4.

On the other hand, power is supplied to the IC chip 11 and input/output signals are supplied and taken out through the I'C lead 12. Pindingtu and Rad 13. Wiring inside chip carrier substrate 14 (
(not shown), chip carrier terminal 19° solder adhesive, wiring board terminal 21 (19, 20, 21 form Hirata contact part 2), and power wiring and signal wiring in wiring board 1 are connected in sequence. It is done. This IC chip 1
1 enables signal exchange with IC chips in other chip carriers.

Returning to FIG. 1, the integrated circuit puff cage of the present invention has the IC chips 11 configured as described above mounted on the wiring board 3 at high density. It exhibits very excellent characteristics in no and no cages. That is, when a plurality of chip carriers 3 are arranged on a wiring board 1 as shown in FIG. 1 and the heat generated by these chips is to be dissipated by a common heat sink 4, it is necessary to fix the heat sink 4 to the chip carrier 3. If this happens, the difference in thermal expansion coefficient between the wiring board 1 and the heat sink 4 will cause a peeling force to act on the Hirata adhesive part 2 between the cytinode carrier 3 and the wiring board 1, and there is a risk that the adhesive will peel off. However, when the chip carrier 3 and the heat sink 4 are connected via the thermal connector 5 as in the present invention, the heat sink 714'! "f y 7"e -
Y! J 7°&dE1i1! ltl[In7>Ip
.

No stress is applied between the chip carrier 3 and the wiring board 1, so that the connection between the chip carrier 3 and the wiring board 1 is ensured.

Furthermore, when the thermal connector 5 is inserted between the heat sink 4 and the chip carrier 2, it not only forms part of the heat dissipation path, but also reduces the gap between the heat sink 4 and the chip carrier 3 due to the elasticity of the heat conductive fibers. It is possible to sufficiently absorb variations and to sufficiently absorb displacement of the chip carrier 3 due to thermal expansion between the wiring board 1 and the heat sink 4.

In the above explanation, examples have been given as the flexible insulating substrate and the heat conductive fiber material, but it goes without saying that other materials may be used. In addition, it is appropriate that the heat conductive fibers have a length of 1.5 to 3 mm and a diameter of about 0.2 ann, but are not limited to this. and the chip carrier cap 16 with appropriate pressure.

〔Effect of the invention〕

As explained above, the present invention has a structure in which a thermal connector is inserted between a chip carrier cap and a heat sink, thereby realizing a high-density integrated circuit package with extremely good heat dissipation characteristics and no internal stress.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an integrated circuit T42 cage according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a part of FIG. 1. Explanation of symbols = 1 is the wiring board, 2 is the Hirata adhesive part. 3 is a chip carrier, 4 is a heat sink, 5 is a thermal connector, 11 is an IC chip, 16 is a chip carrier cap, 17 is silicon rubber, and 18 is a beryllium copper wire. Illustration of spear 2

Claims (1)

[Claims] 1. In a package structure in which a plurality of chip carriers each having an IC chip adhered to and housed on an internal upper surface thereof are provided on a wiring board, and a heat sink is disposed on the upper part to dissipate heat generated from the IC chip, the chip carrier An integrated circuit package characterized in that a thermal connector made of an elastic sheet with thermally conductive fibers is inserted under pressure between a heat sink and a heat sink.