JPH07135279A - Method for packaging multichip module and multichip module package - Google Patents

Abstract

PURPOSE:To provide a method for packaging multichip module by which the breakage of a semiconductor substrate caused by a thermal stress can be prevented and, at the same time, the heat of the substrate can be transferred to a heat sink and a multichip module package. CONSTITUTION:Since gallium 13 is provided at the joint surface of a semiconductor substrate 11 with a heat sink 12, the heat of the substrate is effectively transferred to the heat sink 12 and, therefore, a multichip module package 10 which can reduce the temperature rise of a semiconductor substrate 11 and can prevent the breakage of the substrate 11 can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging method for a multi-chip module and a multi-chip module, and more particularly to a packaging method for a multi-chip module and a multi-chip module for radiating heat generated by a semiconductor substrate using a heat sink. It is suitable for use in packages.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor substrate is housed in a package, a heat sink is provided so as to be in close contact with the semiconductor substrate, so that the heat of the semiconductor substrate is radiated by the heat sink, so that the temperature of the semiconductor substrate is increased. It is designed to reduce the rise. At this time, as shown in FIG. 3, the semiconductor substrate 1 and the heat sink 2 are generally joined by silver epoxy 3.

[0003]

However, the semiconductor substrate 1 and the heat sink 2 are thus formed by the silver epoxy 3.
, The semiconductor substrate 1 and the heat sink 2 have a different coefficient of thermal expansion.
When the surface area of the semiconductor substrate is large, the semiconductor substrate 1
Could be damaged.

As one method for solving such a problem, conventionally, as shown in FIG. 4, there is a method in which an interposer 4 is provided between a semiconductor substrate 1 and a heat sink 2. That is, in this method, the heat sink 2 and the interposer 4 are joined together by the silver epoxy 3A, and the interposer 4 and the semiconductor substrate 1 are joined together by the silver epoxy 3A.
It is designed to be joined by B. Here, as the interposer 4, aluminum nitride or ceramic having a thermal expansion coefficient substantially in the middle of the semiconductor substrate 1 and the heat sink 2 and good thermal conductivity is used.

As another method, instead of the silver epoxy 3, heat radiating silicon is provided between the semiconductor substrate 1 and the heat sink 2 so that the semiconductor substrate 1 and the heat sink 2 are not completely adhered to each other. There are some attempts to avoid damage to the semiconductor substrate due to expansion.

However, in the method of providing the interposer 4 described above, there is still a problem in that damage to the semiconductor substrate 1 is avoided in advance because the thermal stress cannot be completely absorbed. Further, in the method of providing the heat-radiating silicon, the heat resistance is increased, so that the heat of the semiconductor substrate 1 is hard to be transferred to the heat sink 2.
As a result, there is a problem that the temperature of the semiconductor substrate 1 rises.

The present invention has been made in consideration of the above points, and it is possible to prevent damage to the semiconductor substrate due to thermal stress and to effectively transfer the heat of the semiconductor substrate to the heat sink. An attempt is made to propose a packaging method for a chip module and a multi-chip module package.

[0008]

In order to solve such a problem, in the present invention, tungsten 14 is deposited on a predetermined heat radiating member 12 by sputtering, and the surface of the heat radiating member 12 on which tungsten 14 has been deposited is deposited. The gallium 13 in a liquefied state is applied, and the semiconductor substrate 11 having one or a plurality of circuit units mounted thereon is bonded to the gallium 13-coated surface of the heat dissipation member 12 coated with the gallium 13.

Further, in the present invention, the semiconductor substrate 1 is formed by bonding the predetermined heat dissipation member 12 to the semiconductor substrate 11.
In a multi-chip module package 10 configured to conduct the heat generated in 1 to a heat radiating member 12 and radiate the heat, a semiconductor substrate 1 on which a single or a plurality of circuit units are mounted
1, heat dissipation member 12, semiconductor substrate 11 and heat dissipation member 1
Gallium 13 provided on the joint surface of No. 2 and the heat dissipation member 12
And an interposing member 14 interposed between the gallium 13 and the gallium 13.

[0010]

When the semiconductor substrate 11 generates heat, this heat is conducted to the heat sink 12 via the gallium 13. At this time, the gallium 13 is liquefied so that the heat of the semiconductor substrate 11 can be efficiently conducted to the heat sink 12, and the thermal stress due to the thermal expansion of the semiconductor substrate 11 and the heat sink 12 can be completely absorbed. It is possible to reduce the temperature rise of the semiconductor substrate 11 and prevent damage to the semiconductor substrate 11 in advance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a multichip module package as a whole, in which a semiconductor substrate 11 is bonded to a heat sink 12 via gallium 13. As a result, the multichip module 10 conducts the heat of the semiconductor substrate 11 to the heat sink 12 via the gallium 13 to reduce the temperature rise of the semiconductor substrate 11.

The heat sink 12 is made of aluminum and has a groove 15 having a width of 0.3 [mm] and a depth of 0.3 [mm] of 5 [m] on the surface of the semiconductor substrate 11 side.
m] Pitch. Further, a tungsten film 14 is formed on the surface of the heat sink 12 on the semiconductor substrate 11 side, which prevents the heat sink 12 and the gallium 13 from reacting with each other to form a hard alloy.

This multi-chip module package 1
0 can be formed by the following procedure. That is, as shown in FIG. 2, first, a heat sink 1 made of aluminum having a guide frame 16 protrudingly formed on the outer peripheral portion is provided.
The grid-like grooves 15 are formed on the surface of 2 with a pitch of 5 mm. Next, tungsten is deposited on the surface of the heat sink 12 by a sputtering method to form a tungsten film 14 (FIG. 1).
To form.

Next, the heat sink 12 having the tungsten film 14 formed thereon is heated to about 50 [° C.], and in this state, an amount of gallium 13 that wets the entire surface of the heat sink 12 with a thickness of 0.1 [mm] is applied. It is applied to the surface of the heat sink 12. Here, when the gallium 13 is applied to the heat sink 12, the gallium 13 is heated to be liquefied, and the liquefied gallium 13 is dropped on the heat sink 12. At this time, since the grid-shaped grooves 15 are formed on the surface of the heat sink 12, excess gallium 13 enters the grooves 15 and the gallium 13 is uniformly applied to the surface of the heat sink 12.

Next, the semiconductor substrate 11 is attached to the heat sink 12 so as to be fitted into the guide frame 16 of the heat sink 12, and the semiconductor substrate 11 and the gallium 13 are brought into contact with each other. After that, the frame 17 made of aluminum is placed from above the semiconductor substrate 11, and in this state, the frame 17 and the heat sink 12 are fastened with the mounting screws 18. As a result, the frame body 17 is pressure-bonded to the outer peripheral portion of the semiconductor substrate 11, so that the semiconductor substrate 11 and the frame body 17 are bonded together.
Sandwiched between.

In the above structure, when the semiconductor substrate 11 generates heat, the multichip module package 10 conducts this heat to the heat sink 12 via the gallium 13. At this time, gallium 13 has a melting point of 29.78 [° C] and a boiling point of 2300 [° C], so that the semiconductor substrate 11 is liquefied in a relatively low temperature. When the gallium 13 is liquefied, it enters the fine gaps of the semiconductor substrate 11. As a result, the thermal resistance between the semiconductor substrate 11 and the gallium 13 becomes low, so that the heat of the semiconductor substrate 11 is efficiently conducted to the heat sink 12 via the gallium 13.
At this time, gallium 13 is not vaporized due to its low vapor pressure.

Multichip module package 10
The heat of the semiconductor substrate 11 is conducted to the heat sink 12,
When the semiconductor substrate 11 and the heat sink 12 thermally expand,
Since the gallium 13 is in a liquefied state, the gallium 13 completely absorbs the thermal stress of the semiconductor substrate 11 and the heat sink 12. As a result, the multi-chip module package 10 can avoid damage to the semiconductor substrate 11 due to thermal stress.

According to the above structure, the semiconductor substrate 11 and the heat sink 12 are bonded to each other via the gallium 13, so that the heat of the semiconductor substrate 11 can be effectively transferred to the heat sink 12. It is possible to realize the multi-chip module package 10 capable of avoiding damage to the semiconductor substrate 11 due to expansion.

In the above-described embodiment, the case where the tungsten film 14 is attached to the heat sink 12 to prevent the aluminum heat sink 12 and the gallium 13 from reacting with each other to form a hard alloy is described. However, the film formed on the heat sink 12 is not limited to the tungsten film 14, and various materials that do not react with the gallium 13 can be applied.

[0021]

As described above, according to the present invention, by providing gallium on the joint surface between the semiconductor substrate and the heat sink, the temperature rise of the semiconductor substrate can be suppressed, and the semiconductor substrate can be prevented from thermal stress. A multi-chip module package capable of avoiding breakage can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a multi-chip module package according to the present invention.

FIG. 2 is a perspective view for explaining a method for forming a multi-chip module package according to the present invention.

FIG. 3 is a cross-sectional view showing a conventional multi-chip module package.

FIG. 4 is a cross-sectional view showing a conventional multi-chip module package.

[Explanation of symbols]

1, 11 ... Semiconductor substrate, 2, 12 ... Heat sink,
3, 3A, 3B ... silver epoxy, 4 ... interposer, 13 ... gallium, 14 ... tungsten.

Claims (2)

[Claims] 1. A tungsten is deposited on a predetermined heat radiating member by sputtering, and liquefied gallium is applied to the surface of the heat radiating member on which the tungsten is deposited. A packaging method for a multi-chip module, characterized in that a semiconductor substrate having a single or a plurality of circuits mounted thereon is bonded to the surface coated with gallium. 2. A multi-chip module package configured to conduct heat to the heat dissipation member by radiating heat generated in the semiconductor substrate by bonding a predetermined heat dissipation member to the semiconductor substrate, and a single or a plurality of circuits. A semiconductor substrate on which a single body is mounted, a heat dissipation member, gallium provided on a joint surface of the semiconductor substrate and the heat dissipation member, and an insertion member interposed between the heat dissipation member and the gallium. A multi-chip module package characterized by.