JPH04352390A - Heat-dissipating and electromagnetic shielding structure of highly integrated circuit device - Google Patents

Abstract

PURPOSE:To suppress a radiation noise from a highly integrated circuit device without impairing a heat dissipation efficiency in the heat-dissipating and electromagnetic shielding structure of the highly integrated circuit device such as LSI. CONSTITUTION:A passage hole 3a-1 for inserting a heat dissipator 2b immovably provided on the top surface of the package is bored in a shielding conductor 3 including the whole package 2a of a highly integrated circuit device 2 mounted in a circuit board 1, and mounting pins 3a-2 connecting with through holes 1a of the circuit board are projected in the peripheral edge so that the title structure is formed. Then, the package is covered with the shielding conductor, the internal surface of the conductor is brought into contact with the top surface of the package and heat is dissipated while the mounting pins are connected with the through hole so that the package is connected to a signal ground.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation and electromagnetic shield structure for highly integrated circuit devices such as LSIs. LSIs that generate a lot of heat radiate heat by integrally fixing heat dissipation fins on the top surface of the package. Communication systems have become faster in recent years, and LSIs that handle high frequencies and process signals at high speeds generate a lot of heat, so a separate auxiliary heat radiator is attached to the original heat radiating fins to improve heat dissipation efficiency. On the other hand, there has been a delay in responding to the fact that it is one of the sources of electromagnetic radiation. Therefore, it is desired to provide electromagnetic shielding to high frequency LSIs.

0002

2. Description of the Related Art Conventionally, as shown in the perspective view of FIG. 2, an LSI 12 that generates a large amount of heat radiates heat by integrally fixing heat dissipating fins 12b on the upper surface of a package 12a.

0003

[Problem to be solved by the invention] However, LSI
Although it has a high heat generation structure with heat dissipation fins, it has the problem of emitting electromagnetic waves to the surrounding area and causing electromagnetic interference.

In view of the above problems, it is an object of the present invention to provide a heat dissipation/electromagnetic shielding structure for a highly integrated circuit device that can suppress radiation noise from an LSI without impairing heat dissipation efficiency.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the heat dissipation/electromagnetic shielding structure for a highly integrated circuit device of the present invention surrounds the entire package of a highly integrated circuit device mounted on a circuit board. A hole is drilled in the shield conductor through which a heat sink fixed to the top surface of the package is inserted, and a mounting pin is protruded from the periphery to connect to the through hole of the circuit board.The shield conductor is placed over the package and the inner surface is exposed. It is configured to be in contact with the top surface of the package to dissipate heat, and to connect the mounting pin to the through hole for electrical conduction to the signal ground.

[0006]

[Operation] Highly integrated circuit devices can be electromagnetically shielded by surrounding the entire package of the highly integrated circuit device with a shield conductor, attaching the mounting pin of the shield conductor to the through hole, and connecting it to the signal ground for continuity. . Furthermore, by bringing the inner surface of the shield conductor into contact with the upper surface of the package, heat can also be radiated from the shield conductor itself.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention will be explained in detail below based on embodiments shown in the drawings. As shown in the exploded perspective view of FIG. 1, a highly integrated circuit device 2 mounted on a circuit board 1, namely L
It consists of a box-shaped shield conductor 3 that surrounds the entire SI package 2a, that is, upper and lower shield cases.

The upper shield case 3a is formed by bending a metal plate into a square box shape to match the outer shape of the package 2a of the LSI 2 and cover the package 2a from above. and,
A through hole 3a-1 is formed in the ceiling surface through which the heat sink 2b integrally fixed to the top surface of the package 2a is inserted, and through holes 1a (at the signal ground level) of the circuit board 1 are formed at the four corners of the periphery. A mounting pin 3a-2 for insertion and connection is provided protrudingly. The bending height of the periphery (four side walls) is that of the LSI 2 package 2 in which the upper shield case 3a is mounted on the circuit board 1.
When the upper shield case 3a is placed on the package 2a, make sure that the four peripheral corners of the upper shield case 3a do not touch the mounting surface of the circuit board 1 when the upper shield case 3a is placed on the top surface of the package 2a (with the inner surfaces touching). Set to .

[0009] The lower shield case 3b is the package 2
Upper shield case 3a that covers a from below and covers from above
A metal plate is bent into a box shape to fit inside the LS.
Elongated square hole 3b-1 that escapes the lead pin 2a-1 of I2
are perforated on the bottom of each.

Further, an insulating sheet 3c is fitted into the lower shield case 3b, and holes 3c-1 corresponding to the lead pins 2a-1 of the LSI 2 are bored. These components are mounted in a lower shield case 3b fitted with an insulating sheet 3c.
is inserted into the lead pin 2a-1, and the through hole 3 is inserted into the heat sink 2b.
Insert a-1 and insert upper shield case 3a into package 2.
a and fit it on the outside of the lower shield case 3b. Then, connect the mounting pin 3a-2 of the upper shield case 3a and the lead pin 2a-1 of the LSI 2 through the through hole 1a.
1b, and the upper shield case 3a is placed on the upper surface of the package 2a (with the inner surfaces in contact with each other) and connected by soldering.

The lower shield case 3b, which is the lower shield conductor 3, can be replaced by forming a signal ground level conductor pattern (not shown) under the package 2a.

In this way, by surrounding the entire package of a highly integrated circuit device (LSI) with a shield conductor, attaching the mounting pin to the through hole, and electrically connecting it to the signal ground, the highly integrated circuit device can be electromagnetically shielded. radiation noise can be suppressed. Further, even though the shield conductor surrounds the package, by placing the inner surface of the shield conductor on the top surface of the package and making contact with it, heat is radiated from the shield conductor itself, thereby promoting heat radiation.

[0013]

[Effects of the Invention] As detailed above, according to the present invention,
It exhibits extremely useful effects in industry, such as being able to suppress radiation noise from highly integrated circuit devices without impairing heat dissipation efficiency.

[Brief explanation of the drawing]

[Fig. 1] Exploded perspective view of an embodiment according to the present invention

[Figure 2
] Perspective view according to prior art

[Explanation of symbols]

1 is a circuit board 1a, through hole 2 is a highly integrated circuit device (LSI), 2a is a package 2b is a heat sink 3 is a shield conductor (upper and lower shield cases) 3a-
1 is the loophole 3a-2 is the mounting pin

Claims (1)

[Claims] 1. A shield conductor (3) that surrounds the entire package (2a) of a highly integrated circuit device (2) mounted on a circuit board (1), and a heat sink fixed to the top surface of the package (2a). Loop hole (3a-1) for inserting (2b)
and a mounting pin (3a-2) protruding from the periphery to be connected to the through hole (1a) of the circuit board (1), and the shield conductor (3) is connected to the package (2).
A highly integrated circuit device, characterized in that the inner surface of the package (2a) is brought into contact with the upper surface of the package (2a) to dissipate heat, and the mounting pin (3a-2) is connected to the through hole (1a) to be electrically connected to the signal ground. Heat dissipation and electromagnetic shield structure.