JPH07131129A - Double-side-mounted multichip module - Google Patents

Abstract

PURPOSE:To achieve mounting of a chip generating much heat and high density connection between chips by mounting connectors on the periphery of a multichip module board, that serve as external signal connection and feed electric power to LSIs. CONSTITUTION:The figure shows an example where a plurality of processor modules 26 are mounted on a printed wiring board to form a multichip processor. Cooling air flows upward and downward in the figure. Since the heat radiating pathes are distributed on both sides of the multichip module, heat is radiated by efficiently making use of a space where cooling air flows, and the allowable power consumption can be increased. In addition a large number of mutichip modules are connected to the printed wiring board through connectors 16. That is, a mutichip module can be mounted in hook shelf shape; therefore, a problem of increase in mounting area can be solved, and the length of signal lines between multichip modules can be reduced, which leads to improved operation speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chip module which requires high-density connection due to high-speed and high-density mounting of an electronic device system and requires high heat dissipation capability, and particularly, high heat generation. The present invention relates to a multi-chip module that can easily implement chip mounting and high-density chip-to-chip connection.

[0002]

2. Description of the Related Art FIG. 8 shows a cross section of a conventional multi-chip module and a state in which a printed wiring board on which the multi-chip module is mounted is mounted on a shelf. Where 1 is
LSI chip, 2 is a TAB (Tape Automated Bonding) for connecting the LSI chip 1 to a multi-chip substrate, and 3 is a multi-chip module using alumina or the like as an insulating layer material.
(MCM) board, 4 are I / O pins for signal connection and power supply between the MCM board 3 and the printed wiring board 8, and 5 are caps for mechanically protecting the LSI chip 1 mounted on the MCM board 3. , 6 is a heat sink for radiating heat generated from the LSI chip 1 to the surrounding air, 7 is a general component, and 8 is
A printed wiring board on which the MCM board 3 and general parts 7 are mounted,
9 is a connector for connecting signals between the printed wiring boards 8 via the backboard 11, 10 is a connector pin, 11 is a signal connection between the printed wiring boards 8, and each printed wiring board 8
Shows a backboard for power supply to. Note that the cooling air flows in the vertical direction on the paper surface.

In a multi-chip module having a conventional structure (generally a multi-chip module substrate 3, an LSI chip 1 and I / O pins 4), components are mounted only on one side of the multi-chip module substrate 3. , LS
The heat generated by the I-chip is the multi-chip module board 3
It is guided to the heat sink 6 via and is radiated to the air.
However, since all the heat radiation directions are the same, there is a problem that, for example, the LSI chip 1 with low power consumption is also affected by the high heat generation LSI chip and becomes high temperature.

Further, since all the heat is dissipated in one direction, the heat cannot be dispersed, and the heat sink 6 is required even if the low power consumption LSI that originally requires no heat sink is mounted, and Inevitably, there is also the problem of requiring a large heat sink. Therefore, as shown in FIG. 8, it is necessary to increase the distance between the printed wiring boards 8, resulting in an increase in signal transmission distance and a decrease in system operating speed.

Further, assuming that the multi-chip module as shown in FIG. 8 is a module composed of a microprocessor and a large number of cache memories such as a processor module, it is necessary to arrange the chips two-dimensionally in the prior art. Therefore, there is a difference in the distance from the microprocessor to each cache memory, and the performance of the system is determined by the wiring distance to the cache memory arranged farthest away. This is because the components can be mounted on the multi-chip module only in two dimensions. Therefore, in the conventional multi-chip module, components have been mounted at high density by making use of expensive technology such as thin film technology, and the wiring distance has been shortened. However, as the cost of the multi-chip module rises and the assembly requires dramatically advanced technology, the production yield is deteriorated, which is not suitable for mass production.

Further, the conventional multi-chip module has often been mounted opposite to a mother board on which it is mounted, that is, two-dimensionally mounted on the mother board. However, if you try to mount a large number of multi-chip modules on the motherboard, it will become an area neck, and as a result, you will need to take measures such as mounting separately on multiple motherboards, and you will need a new connector connection. In addition, there were many problems in signal propagation.

[0007]

As described above,
The conventional multi-chip module mounting method has many problems in production and mounting.

An object of the present invention is to solve the problems of the above-mentioned prior art and to easily mount a high heat generating chip and facilitate high-density chip-to-chip connection in response to an electronic device system that requires high speed. It is to provide a novel multi-chip module mounting structure that can be realized.

[0009]

Means for Solving the Problems The above object is provided with at least one or more LSIs, wiring for connecting a signal net between the LSIs, and a connector for performing signal connection and power supply with the outside. In the multi-chip module board, the high-heat-generating LSIs are arranged on both sides of the multi-chip module board, and the mounting areas are not vertically aligned. A heat sink is provided on the opposite surface, and a connector for controlling signal connection to the outside and power supply to the LSI mounted on the multi-chip module board is mounted on the periphery of the multi-chip module board. This can be achieved by using a double-sided mounting type multi-chip module.

A second feature of the present invention is that the peripheral portion of the multi-chip module is provided with a connector capable of vertically mounting and connecting the multi-chip module to a mother board on which at least one multi-chip module is mounted. To do.

[0011]

With the above structure, the heat radiation can be distributed to both sides of the multi-chip module, so that the concentration of heat generation can be avoided and the cooling air around the multi-chip module can be effectively used. The fact that heat can be dissipated by heat is significantly different from the prior art.

Further, since heat sinks can be individually provided to the high heat generating chips, the heat sink size can be reduced, and the component height of the multi-chip module can be reduced, and as a result, signals between the multi-chip modules can be reduced. The point that the propagation can be shortened is greatly different from the conventional technology.

Further, since it is not necessary to provide an unnecessary heat sink on the chip of low power consumption, the point that the cost can be reduced is greatly different from the prior art.

Furthermore, since the components are mounted on both sides, the signal wiring distance between the components can be shortened. For this reason, the wiring distance can be shortened without using expensive wiring technology such as thin film technology, and for example, a conventionally used printed wiring board or the like can be adopted, so that the cost can be significantly reduced. Is significantly different from the conventional technology.

As described above, the present invention also provides, on the peripheral portion of the multi-chip module board, a connector for mounting and connecting the multi-chip module in a vertical direction to a motherboard on which at least one multi-chip module is mounted. This is the second feature.

Therefore, when a single processor is constructed by the multi-chip module of the present invention and a multi-processor using a plurality of the single processors is constructed, a large number of multi-chip modules can be connected to the motherboard through the connector. it can. That is, since the multichip module can be mounted in a bookshelf shape, the problem of the mounting area can be overcome, and the signal wiring distance between the multichip modules can be shortened, so that the operation speed can be improved. to differ greatly.

[0017]

EXAMPLES The multi-chip module of the present invention will be specifically described below with reference to examples.

[0018]

[Embodiment 1] FIG. 1 is a sectional view showing the structure of an embodiment of the multichip module of the present invention.

Here, 1 is an LSI chip, 2 is a TAB (Tape
(Automated Bonding part), 13 is a small heat sink provided individually on the high heat generation chip, 14 is potting resin for protecting the LSI chip 1, 15 is a relatively low power consumption surface mounting component such as memory, and 16 is a multi-chip module. 1 is a connector housing provided on one side, 17 is an I / O pin for connection, 18 is a printed wiring board which is a multi-chip module board, and 19 is a thermal via provided in the printed wiring board 18. 2 is a view of the multi-chip module of FIG. 1 viewed from the front surface side and the back surface side.

In this embodiment, the high heat generating chips 1 are mounted on both surfaces of the printed wiring board 18 to disperse the heat generation. Since the printed wiring board 18 generally has low thermal conductivity, thermal vias 19 are provided in this example to reduce the thermal resistance from the high heat generating chip 1 to the small heat sink 13. For example, assuming that the high heat generation chip 1 is a microprocessor or a floating point arithmetic processor, surface mounting parts
Assuming a cache memory as 15, since the components are mounted on both sides, the wiring distance can be shortened by effectively using the through holes penetrating both sides of the board, and as a result, it is possible to manufacture at low cost. Even if the possible printed wiring board 18 is used, the connection distance can be shortened, and the same effect as in the case where the wiring distance is shortened by using the conventional thin film wiring technology can be obtained.

[0021]

[Embodiment 2] FIG. 3 is a view showing a second embodiment of the present invention, in which 12 is an alumina substrate, which is a typical inorganic material, and 20 is a two-stage structure of wire bonding provided in the alumina substrate 12. Reference numeral 21 denotes a wire bonding portion, and 22 denotes a bonding pad provided on the alumina substrate 12 side for realizing the cavity portion. In the case of the present embodiment, when a material having a low dielectric constant such as glass ceramics (a kind of inorganic material) is used as the substrate material in order to further improve the wiring accommodating property, the thermal conductivity is also reduced. It is effective in such applications.

[0022]

[Embodiment 3] FIG. 4 is a sectional view showing a third embodiment of the present invention, and 23 shows a heat spreader made of metal. In this embodiment, in order to make heat dissipation more effective, a cavity 20 is provided in the mounting portion of the high heat generation chip 1, and a metal heat spreader having high thermal conductivity is inserted therein, and by this, The thermal resistance from the heat generating chip 1 to the heat sink 13 can be greatly reduced.

[0023]

[Embodiment 4] FIG. 5 is a sectional view showing a fourth embodiment of the present invention, in which 24 is a solder ball which is an example of flip-chip connecting chips, and 25 is a surface corresponding to flip-chip connecting. An LSI chip with modified pads is shown.

This embodiment shows an example corresponding to an LSI having an increasing number of terminals. In this case, a heat radiation bump is provided and a thermal via 19 is provided immediately below the bump so that it can be easily mounted. it can. That is, the present invention is effective for increasing the number of terminals of the device.

[0025]

[Embodiment 5] FIG. 6 is a sectional view showing a fifth embodiment of the present invention. In this case, an alumina substrate having a relatively high thermal conductivity is adopted as a substrate, and a thermal via or the like is unnecessary. There is.

[0026]

Sixth Embodiment FIG. 7 is a cross-sectional view showing a sixth embodiment of the present invention, in which 26 is a single processor module. This embodiment shows an example in which a plurality of processor modules 26 are mounted on the printed wiring board 8 to construct a multiprocessor. In the present embodiment, the cooling air flows above and below the paper surface. Since the heat dissipation paths are distributed on both sides of the multi-chip module, the space where the cooling air flows can be effectively used for heat dissipation, and as a result,
The allowable power consumption can be improved.

Further, a number of multi-chip modules can be connected to the printed wiring board 8 which is a mother board via the connector 16. That is, since the multichip module can be mounted in a bookshelf shape, the problem of increasing the mounting area can be solved, and the signal wiring distance between the multichip modules can be shortened, so that the operation speed can be improved.

[0028]

As described above, the multi-chip module of the present invention is used as the multi-chip module to solve the problems of the prior art.
It has been possible to provide a novel multi-chip module mounting structure capable of easily realizing high heat generation chip mounting and high-density chip-to-chip connection corresponding to an electronic device system that requires high speed.

That is, since the heat radiation can be distributed to both sides of the multi-chip module, the concentration of heat generation can be avoided, and the cooling air around the multi-chip can be effectively utilized to radiate heat. In addition, since a heat sink can be provided individually for each high heat generation chip, the heat sink size can be reduced, and the component height of the multi-chip module can be reduced. As a result, the signal propagation between the multi-chip modules can be shortened. is there. In addition, since it is not necessary to provide an unnecessary heat sink on the chip with low power consumption, there is an advantage that the cost can be reduced.
Furthermore, since the components can be mounted on both sides, the signal wiring distance between the components can be shortened. Therefore, the wiring distance can be shortened without using expensive wiring technology such as thin film technology, and for example, a conventionally used printed wiring board or the like can be adopted,
There is an advantage that the cost can be significantly reduced.

According to the second feature of the present invention, when a single processor is constructed by a multi-chip module and a multi-processor using a plurality of the multi-chip modules is constructed, a large number of multi-chip modules are provided on the motherboard through the above connector. Can be connected. That is, since the multi-chip module can be mounted in a bookshelf shape,
Since the problem of mounting area can be overcome and the signal wiring distance between multi-chip modules can be shortened,
There is an advantage that the operation speed can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of a first embodiment of the present invention.

2A and 2B are a top view and a back view of the double-sided mounting type multi-chip shown in FIG.

FIG. 3 is a sectional view showing a configuration of a second embodiment of the present invention.

FIG. 4 is a sectional view showing the configuration of a third embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing the configuration of a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing the structure of a sixth embodiment of the present invention.

FIG. 8 is a sectional view of a conventional multi-chip module mounted on a shelf.

[Explanation of symbols]

1 ... LSI chip, 2 ... TAB (Tape Automated Bondin
g) 3 ... MCM board, 4 ... I / O pins, 5 ... Protective cap, 6 ... Heat sink, 7 ... General parts, 8 ... Printed wiring board, 9 ... Connector, 10 ... Connector pin, 11 ... Backboard, 12 … Alumina substrate, 13… Heat sink, 14… Potting resin, 15… Surface mount component, 16… Connector housing, 17… I / O pin, 18… Printed wiring board, 19… Thermal via, 20… Cavity, 21… Wire bonding Part, 22 ... Bonding pad, 23 ... Metal heat spreader, 24 ... Solder ball, 25 ... Flip chip type LSI
Chip, 26 ... Processor element.

Claims (2)

[Claims] 1. At least one LSI is mounted,
In a multi-chip module board equipped with wiring for connecting signal nets between LSIs and a connector for signal connection and power supply to the outside, high heat-generating LSIs are mounted on both sides of the multi-chip module board. The areas are arranged so that they do not match vertically, and a heat sink is placed on the facing surface of the high heat generation LSI mounted on the multi-chip module board. A double-sided mounting type multi-chip module, which is equipped with a connector for signal connection and power supply to the LSI mounted on the multi-chip module substrate. 2. The double-sided structure according to claim 1, wherein a connector for mounting and connecting the multi-chip module in a vertical direction to a mother board on which at least one multi-chip module is mounted is provided in the peripheral portion of the multi-chip module. Mounted multi-chip module.