JPH0878616A - Multi-chip module - Google Patents

Abstract

PURPOSE: To obtain a substrate for a multi-chip module capable of increasing a mounting density by mounting semiconductor elements on both the surfaces of the substrate thereby effectively utilizing the surfaces of the substrate and also capable of providing good heat radiation. CONSTITUTION: A metal plate 23 for heat radiation is sandwiched between at least two alumina laminated substrates 21 and 22 and simultaneously baked as one united body, which contains substrates mounting semiconductors on both the surfaces, a ceramics package 29 having a thermal via 32 inside which is connected to at least part of the metal plate 23 of the substrate when the substrate has been mounted, and a heat radiating member 36 attached to the ceramic package 29 in such a manner that it can be connected to the thermal via 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, by mounting a plurality of semiconductor elements on a single substrate at high density, wiring delay between the elements can be reduced and high speed operation can be realized. Regarding multi-chip modules. The multi-chip module is an excellent method for mounting high-speed semiconductor devices, but it is necessary to efficiently dissipate heat generated by a plurality of semiconductor devices.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional multichip module (conventional structure 1) in which a plurality of semiconductor elements are mounted on both front and back surfaces of a substrate. A plurality of semiconductor elements 2 are mounted on both front and back surfaces of the substrate 1.
Are connected to a conductor pattern (not shown) on the substrate 1 by bonding wires 3. Board 1 and external leads 4
Is also connected by a bonding wire 5, and the substrate 1 including the plurality of semiconductor elements 2 is hermetically sealed with a resin 6 such as epoxy by transfer molding to form a plastic package 7. Radiating fins 8 are attached to the outer surface of the resin 6 to dissipate the heat of this package, especially the heat of the plurality of semiconductor elements 2. Reference numeral 9 is a through hole for establishing conduction between patterns (not shown) on the front and back surfaces of the substrate 1.

FIG. 5 shows a conventional example (conventional structure 2) using a ceramic package having a lower thermal resistance than a plastic package. In FIG. 5, a plurality of semiconductor elements 12 are mounted on one surface (lower surface in FIG. 5) of a ceramic package (ceramic substrate) 11, and these semiconductor elements 12 are bonded by a bonding wire 13 to a conductor pattern (see FIG. Connected (not shown). A cap 15 covers the rising portion of the periphery of the ceramic package 11 to protect the semiconductor element 12 inside. Radiating fins 18 are attached to the surface of the ceramic package 11 opposite to the semiconductor element 12, and external leads 14 are connected to the ceramic package 11. The connection between the semiconductor element 12 and the external lead 14 is made by a wiring pattern (not shown) inside the ceramic package 11.

[0004]

Regarding the conduction of heat generated from the semiconductor element in the conventional multi-chip module as described above, the heat is transferred to the package through the substrate, or the semiconductor element is directly connected to the package. There is a method to transfer heat to the package, but in either method, the board and the package have high thermal resistance (especially,
The plastic package 7 shown in FIG. 4 has a high thermal resistance), which causes a decrease in thermal conductivity.

That is, in the conventional double-sided mounting multi-chip module substrate as shown in FIG. 4, it is possible to mount the semiconductor elements 2 on both front and back surfaces to increase the mounting density. There was a problem in heat dissipation from the substrate. Further, since the double-sided mounting multichip module substrate as shown in FIG. 4 is a plastic package, it has poor thermal conductivity and cannot be applied to a device with large power consumption.

On the other hand, in the conventional multi-chip module substrate using the ceramic package as shown in FIG. 5, the heat of the semiconductor element 12 is the ceramic package 11.
The heat radiation is good through the heat radiation fins 17 through itself, but the heat radiation is good, but it is difficult to increase the packaging density because the semiconductor elements 12 can be mounted on only one side of the ceramic package 11.

Therefore, the present invention provides a substrate for a multi-chip module, in which semiconductor elements are mounted on both sides of the substrate, the substrate surfaces can be effectively used to increase the mounting density, and the heat dissipation is good. With the goal.

[0008]

In order to solve such a problem, according to claim 1, as shown in FIG. 3, at least two alumina laminated substrates 2 for heat dissipation are provided.
A substrate for a multi-chip module is provided, which is provided with a substrate 20 sandwiched between Nos. 1 and 22 and co-fired to be integrated so that a semiconductor element 26 can be mounted on both surfaces.

According to claim 2, in FIG. 3, the metal plate 2 is formed on the alumina laminated substrates 21 and 22 from the surface of the substrate 20.
The substrate for a multi-chip module according to claim 1, wherein the through holes up to 3 are provided with thermal vias 28 formed by filling a material having a good thermal conductivity. According to claim 3, as shown in FIGS. 1 and 3,
A substrate 20 having a metal plate 23 for heat radiation sandwiched between at least two alumina laminated substrates 21 and 22 and simultaneously fired to be integrated, and a semiconductor element 26 mounted on both surfaces, and a thermal via 32 inside and the substrate 20. Board 20 when 20 is mounted
A ceramic package 29 configured such that at least a part of the metal plate 23 is connected to the thermal via 32,
A multi-chip module is provided, which includes a heat dissipation member 36 attached to the ceramic package 29 so as to be connected to the thermal via 32.

[0010]

According to the present invention, the heat of the semiconductor elements 26 mounted on both surfaces of the substrate is efficiently radiated through the metal plate 23 which is integrated with the alumina laminated substrates 21 and 22, so that the mounting density is high. Moreover, it is possible to obtain a multi-chip module having good heat dissipation.

According to the second aspect, the heat of the semiconductor elements 26 mounted on both surfaces of the substrate 20 is transferred to the metal plate through the thermal vias 28, so that the heat is radiated more efficiently. According to claim 3, the heat of the semiconductor elements mounted on both sides of the substrate 20 is efficiently radiated through the metal plate 23 which is integrated with the alumina laminated substrates 21 and 22, and further through the thermal vias 32 of the ceramic package. Since the heat is radiated to the heat dissipation member 36, a multi-chip type semiconductor device having a high packaging density and good heat dissipation can be obtained. In claim 3, when the thermal vias 28 are provided in the alumina laminated substrates 21 and 22 of the substrate 20 as in claim 2, the heat dissipation is further improved.

[0012]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a sectional view of a substrate for a multichip module of the present invention. 2A, 2B and 2C are plan (surface) views showing a substrate used in the present invention,
It is a back view and a sectional view. FIG. 3 is a partially enlarged sectional view of the substrate for a multichip module of the present invention.

First, as shown in FIG. 2, between two rectangular flat plate-shaped alumina laminated substrates 21 and 22, a metal plate for heat dissipation, such as a Kovar plate, which has a thermal expansion coefficient close to those of the alumina substrates 21 and 22. Metal plate with good thermal conductivity 2
3 is sandwiched and co-fired to form a substrate 20 having good thermal conductivity. The metal plate 23 is a substantially rectangular flat plate like the alumina laminated substrates 21 and 22, but has portions 23a protruding outward from the alumina laminated substrates 21 and 22 at four corners. These protruding portions 23a are for releasing heat from the substrate 20 as described later.

The uppermost surface of the substrate 20 (alumina laminated substrate 21)
In the upper part, in addition to a conductor pattern (not shown) for mounting components, solder bumps 24 are provided as shown in FIG. The bump connection is done with. On the other hand, substrate 2
On the lowermost surface of 0 (on the alumina laminated substrate 22), in addition to the conductor pattern (not shown) for mounting components, the conductor pads 25 for wire bonding as shown in FIG. It is provided and is connected to the ceramic package by wire bonding as described later.

FIG. 3 is an enlarged view showing a state in which the semiconductor element 26 is mounted on both front and back surfaces (alumina laminated substrates 21 and 22) of the substrate 20 by the bonding wires 27. The alumina substrates 21 and 22 are provided with thermal vias 28 corresponding to the positions of the semiconductor elements 26 and extending from the semiconductor elements 26 to the Kovar metal plate 23. These thermal vias 28 are formed by filling through holes penetrating the alumina substrates 21 and 22 with a substance having good thermal conductivity, such as metal powder, and have a role of radiating the heat of the semiconductor element 26 to the metal plate 23. To do.

FIG. 1 shows a QFP type semiconductor package in which a substrate 20 on which a semiconductor element 26 is mounted is mounted on a ceramic package 29. The ceramic package 29 has two step portions for mounting the substrate 20. That is, the step portion 30 and the metal plate 2 for connecting the solder bumps 24 of the front side alumina substrate 21.
3 is a step portion 31 with which the protruding portion 23a of 3 contacts. A thermal via 32 penetrating the ceramic package 29 is formed in the step portion 31. Therefore, the solder bumps 24 of the substrate 20 may be connected to the ceramic package 29.
The conductor portion formed on the stepped portion 30 is connected by soldering, and thereby the electric connection is made between the substrate 20 side and the ceramic package 29 side. At the same time, the protruding portion 23a of the metal plate 23 is connected to the thermal via 32 in the step portion 31 of the ceramic package 29 by high-temperature solder or an adhesive having high thermal conductivity. On the other hand, the bonding pad 25 of the back side alumina substrate 22 is connected to the conductor portion of the ceramic package 29 by wire bonding 33.

External leads 34 are connected to the ceramic package 29, and the side of the substrate 20 is covered with a cap 35. In addition, the substrate 2 of the ceramic package 29
A radiation fin 36 is connected to the surface opposite to 0. As a result, the heat from the semiconductor element 26 is transferred to the thermal via 28.
The heat is dissipated to the metal plate 23 through the through holes, and is further efficiently dissipated to the outside by the heat dissipating fins 36 through the thermal vias 32 of the ceramic package 29.

[0018]

As described above, according to the present invention,
Multiple semiconductor elements can be mounted at high density, and even in a multi-chip module that consumes a large amount of power, it is possible to mount components on both sides of the board at high density and obtain a semiconductor device with good heat dissipation. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multichip module of the present invention.

2A is a plan (front) view of a substrate for a multichip module used in the present invention, FIG. 2B is a rear view of the substrate, and FIG. 2C is a sectional view of the substrate.

FIG. 3 is an enlarged cross-sectional view showing a state in which a semiconductor element is mounted on a substrate for a multi-chip module used in the present invention.

FIG. 4 is a sectional view showing an example of a conventional multi-chip module (particularly, a plastic package).

FIG. 5 is a cross-sectional view showing another example of a conventional multi-chip module (particularly, a ceramic package).

[Explanation of Codes] 20 ... Substrate 21, 22 ... Alumina Laminated Substrate 23 ... Metal (Kovar) Plate 24 ... Solder Bump 25 ... Bonding Pad 26 ... Semiconductor Element 27 ... Wire 28 ... Thermal Via 29 ... Ceramic Package 30, 31 ... Step 32 ... Thermal via 33 ... Wire 34 ... Lead 35 ... Cap 36 ... Radiating fin

Claims (3)

[Claims] 1. At least two metal plates (23) for heat dissipation are provided.
A substrate for a multi-chip module, comprising a substrate (20) sandwiched between a plurality of alumina laminated substrates (21, 22) and simultaneously fired to be integrated, and a semiconductor element (26) can be mounted on both surfaces. . 2. A thermal via (28) formed by filling a through hole extending from the surface of the substrate (20) to the metal plate (23) with a substance having good thermal conductivity in the alumina laminated substrate (21, 22). The multi-chip module substrate according to claim 1, wherein the substrate is provided. 3. At least two metal plates (23) for heat dissipation are provided.
A substrate (20) sandwiched between a plurality of alumina laminated substrates (21, 22) and simultaneously fired to be integrated with each other and semiconductor elements (26) mounted on both sides, and a thermal via (32) inside the substrate (20). A ceramic package (29) configured such that at least a part of the metal plate (23) of the substrate (20) is connected to the thermal via (32) when the component (20) is mounted.
And a heat dissipation member (3) attached to the ceramic package (29) so as to be connected to the thermal via (32).
6) A multi-chip module comprising: