JPH07131132A - Structure for mounting multichip module - Google Patents

Abstract

PURPOSE:To provide a structure for mounting a multichip module composed of a plurality of chips mounted on a board, wherein the cooling efficiency is improved despite high density mounting. CONSTITUTION:A plurality of semiconductor chips 34 is supported and secured in layers between two opposite supporting boards 31a, 31b to form a first module 22. A specified number of cooling holes 41 are formed in a mother board 23. The first modules 22 are mounted direct above the cooling holes 41.

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 mounting structure for mounting a plurality of chips on a substrate.

In recent years, with the demand for higher speed and smaller size of consumer electronic devices, computers, etc., there has been a demand for a circuit board capable of high-density mounting of semiconductor elements and high-speed transmission. For that purpose, since the amount of heat generated by the increase in the number of semiconductor elements increases, it is necessary to efficiently cool the semiconductor elements.

[0003]

2. Description of the Related Art Conventionally, there is a multi-chip module for high-density mounting of semiconductor elements. This multi-chip module is one in which a plurality of bare chips having the same function or different functions are mounted on a substrate and packaged.

Therefore, FIG. 4 shows a plan view of a conventional multi-chip module. In FIG. 4, the multi-chip module 11 includes a plurality of bare chips 1 on a substrate 12.
3a to 13e are mounted, the package 14 is formed by transfer molding, and I / O pins (leads) are extended from four sides of the package 14 to form a predetermined shape (for example, a gull wing shape) to form a QFP ( Quad
Flat Package) type.

The substrate 12 is, for example, formed on a silicon wafer in a multilayer structure of an organic insulating thin film and a metal conductor thin film, or is formed of a co-fired ceramic multilayer structure. When a ceramic multilayer substrate is used as the substrate 12, a PGA (Pin Grid Array) type in which I / O pins (leads) are extended from the package bottom surface may be used.

In addition, bare chips 13a to
For mounting 13e, wire bonding with a wire,
TAB (Tape Automated Bondi) using a flip chip with solder and a carrier tape with a wiring pattern
There is a chip carrier including ng) method.

Since the multi-chip module 11 as described above has a large amount of heat generation, it is cooled according to the number of bare chips mounted. For example, in the case of FIG. 4, the package 14 is opened and the bare chips 13a to 1a
3e is exposed, and a heat sink is provided in contact with the bare chips 13a to 13e. When the heat sink is insufficient, forced air cooling by a fan, heat transfer water cooling method in which cooling water is circulated by bellows or the like with a cold plate interposed, or liquid cooling by immersion in an electrically insulating liquid is performed.

[0008]

However, in high-density mounting of bare chips in a multi-chip module, cooling efficiency must be increased when the number of chips mounted on a substrate increases, and the cooling device becomes large. There is a problem of doing. Further, there is a problem that the cooling effect of the space deteriorates when the chips come close to each other due to the increase in the number of chips.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a mounting structure of a multi-chip module for improving cooling efficiency by high-density mounting.

[0010]

SUMMARY OF THE INVENTION The above-mentioned problem is that two supporting substrates having a predetermined pattern and a connection terminal portion are formed, and a predetermined number of semiconductor chips connected to the pattern are stacked at predetermined intervals and face each other. A first module supported and fixed from, a pattern connected to the connection terminal portion of the first module and an external connection terminal are formed,
This is solved by providing a configuration in which a predetermined number of holes are formed and a mounting board on which the first module is mounted is mounted on each of the holes.

[0011]

As described above, the plurality of semiconductor chips are supported and fixed by being opposed to the two supporting substrates to form the first module. On the other hand, the mounting board has a predetermined number of holes, and the first module is mounted on each of the holes.

As described above, since the first module is formed in a state where the semiconductor chips are stacked and a predetermined number of the first modules are mounted on the mounting board, higher density mounting can be achieved as compared with the conventional one. It is possible. In this case, since the holes are formed in the first module portion of the mounting board, the cooling medium can be penetrated during cooling, and the cooling efficiency can be improved.
This means that even if the packaging density is higher than in the past, it is not necessary to increase the size of the cooling means.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of an embodiment of the present invention.
1A is a schematic perspective view of the first module, FIG.
(B) is a schematic perspective view of a mounting substrate.

The multi-chip module 21 shown in FIG.
Is the first module 22 and this first module 2
The mother board 23 is a mounting board on which 2 is mounted.

In FIG. 1A, the first module 2
For 2, two support substrates 31a and 31b are prepared. The support substrates 31a and 31b are, for example, Cu-W (copper
A pattern layer 33 of a thin film multilayer in which a plurality of thin films each having a pattern formed by spin-coating polyimide and forming a pattern by lift-off are laminated on a base 32 of tungsten alloy.
Are formed.

On the pattern layer 33, patterns and connection terminals (not shown) are formed. In FIG. 1A, connection terminals are formed on the back side (back side) of the pattern layers 33 of the support substrates 31a and 31b.

Then, the plurality of semiconductor chips 34 are die-bonded in a state of being stacked between the two support substrates 31a and 31b at a predetermined interval. That is, the support substrate 3 is provided on the opposite side of the stacked semiconductor chips 34.
It is supported and fixed by 1a and 31b. Then, the pattern layers of the respective support substrates 31a to 31b and the respective semiconductor chips 34 are electrically connected by the solder 35. In this case, a gap 36 is formed between the semiconductor chips 34. In addition,
The semiconductor chip 34 may be flip-chip mounted on the support substrates 31a and 31b.

The mother board 23 shown in the first (B) section
Are formed with a predetermined number of cooling holes 41, and the cooling holes 41 are not formed. A predetermined pattern, a component chip, and external connection terminals (not shown) are formed in a thin film multilayer on the surface region. The circuit layer 42 is formed.

Here, FIG. 2 shows a manufacturing explanatory view of the motherboard of the present invention. In FIG. 2, first, a green sheet is formed (first step). For the green sheet, 2 wt% yttrium oxide (slurry) is added to aluminum nitride powder, PVB (polyvinyl butyral), DBP (dibutyl phthalate), and ethanol slurry are added to these prepared powders and mixed by a ball mill.

After defoaming this, it is molded by the doctor blade method to obtain a green sheet of 90 mm square and 300 μm in thickness, for example. Here, the doctor blade method is
It is a method of flatly extending through a gap between metal blades called a doctor blade. Then, the soft green sheet having plasticity produced by drying this is cut into a predetermined size.

Subsequently, the green sheet is, for example,
A predetermined number of 0 mm square hollow holes (regardless of shape) are formed (second step), and 10 holes, for example, are stacked. Cooling holes 41 are formed by the superposed hollow holes,
Silicon rubber is filled in the cooling holes 41 in order to prevent contraction during pressing (third step).

After that, the layers are pressed and laminated at a temperature of 100 ° C. or less for a predetermined time (fourth step). After pressing
Remove the silicone rubber and apply 5 at 1600 ℃ in a nitrogen atmosphere.
Firing is performed for a time to obtain a multilayer substrate (fifth step). This multilayer substrate is mechanically polished to, for example, a surface roughness (Rmax) of 0.5.
A substrate of μm is prepared (sixth step).

After that, copper wiring to be a conductor layer is formed on the surface of the substrate by a sputtering method, and polyimide to be an insulating layer is spin-coated to form a film. Further, tin oxide serving as a resistance layer and titanium barium oxide serving as a capacitor layer are formed to form a circuit layer (seventh step).

Then, an I / O terminal 43 serving as an external connection terminal, for example, a pad-shaped conductor having a shortened pin is formed on the lower portion of the substrate in FIG. 1B, and, for example, Au ( Gold) It is formed by applying gold plating (eighth step).

Therefore, referring back to FIG. 1B,
Motherboard 23 in which cooling holes 41 are formed as described above
Is a hole that allows the cooling medium to pass through the cooling medium during forced cooling. Then, the first module shown in FIG. 1A is mounted on the cooling hole 41.

Next, FIG. 3 shows a mounting perspective view of the present invention. In FIG. 3, the first module 22 is mounted above each of the cooling holes 41 of the motherboard 23 by, for example, solder connection to form the multi-chip module 21. In this case, the gaps 36 formed between the respective semiconductor chips 34 in the first module 22 and the cooling holes 41 concerned.
And are communicated.

Such a multi-chip module 21
The I / O terminal 43 portion is inserted and connected to the connector 44 provided in, for example, the cooling module.
The cooling by the cooling module is forced air cooling as described above,
Either conduction cooling or liquid cooling may be used, and it is appropriately selected depending on the number of semiconductor chips 34. Incidentally, in the case of liquid cooling, for example, it is immersed in a heat transfer inert liquid such as Fluorinert (fluorocarbon).

As described above, by mounting a predetermined number of the first modules 22 on which the plurality of semiconductor chips 34 are superposed on each other on the mother board 23, the mounting density in the conventional surface mounting as shown in FIG. It is possible to obtain a packaging density 100 times higher, and it is possible to reduce the size and density of the multichip module. The increase in the amount of heat generated due to this can be coped with by the cooling module of the conventional scale by improving the cooling efficiency by forming the cooling holes 41 in the mother board 23.

[0029]

As described above, according to the present invention, the plurality of semiconductor chips are supported and fixed by facing the two supporting substrates to form the first module, and the first module is formed above the hole formed in the mounting substrate. It is possible to improve the cooling efficiency by high-density mounting.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a manufacturing explanatory diagram of the motherboard of the present invention.

FIG. 3 is a mounting perspective view of the present invention.

FIG. 4 is a plan configuration diagram of a conventional multi-chip module.

[Explanation of symbols]

 21 Multi-Chip Module 22 First Module 23 Motherboard 31a, 31b Support Substrate 32 Base 33 Pattern Layer 34 Semiconductor Chip 35 Solder 36 Gap 41 Cooling Hole 42 Circuit Layer 43 I / O Terminal 44 Connector

Claims (4)

[Claims] 1. Two support substrates (31a, 31) having a predetermined pattern (33) and a connection terminal portion (33) formed thereon.
The connection between the first module (22) and the first module in which a predetermined number of semiconductor chips (34) connected to the pattern (33) are stacked at predetermined intervals and supported and fixed from the opposite side according to b). A pattern connected to the terminal part (32) and the external connection terminal (43) are formed, and a predetermined number of holes (41) are formed, and the first part is formed on each of the holes (41). Module (22)
A mounting structure for a multi-chip module, comprising: a mounting substrate (23) on which the respective components are mounted. 2. A gap (36) generated in each of the semiconductor chips (34) of the first module (22) and a hole (41) of the mounting substrate (23) are communicated with each other to make the first gap. The mounting structure for a multi-chip module according to claim 1, wherein the module (22) is mounted. 3. The mounting structure of a multi-chip module according to claim 1, wherein the supporting substrates (31a, 31b) of the first module (22) are formed of thin film multilayers. 4. The mounting substrate (23) is formed of a thin film multilayer, and is configured to include a layer (42) on which a component chip is formed in addition to the pattern.
Mounting structure of the described multi-chip module.