JP3728836B2 - LSI package cooling device and fixing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an LSI package cooling device for cooling an LSI package that generates high heat and large radiation noise and to suppress radiation noise, which is mounted on an electronic circuit board of an electronic device, and a fixing method thereof.
[0002]
[Prior art]
Conventionally, a configuration of a heat sink used for cooling an LSI package is disclosed, for example, in JP-A-8-222667. As shown in FIG. 3A, the heat sink 30 is bonded to the upper surface of the LSI package 34 by protrudingly forming an adhesive seat 35 on a part of the bottom surface, and in the gap between the bottom surface portion other than the adhesive seat 35 and the LSI package 34. Was filled with a rubber sheet 33 having a thickness slightly larger than the gap and excellent in thermal conductivity.
[0003]
However, in the conventional heat sink configuration, the heat sink is fixed only by bonding the LSI package and the heat sink. For example, when conductive copper or the like is used for the heat sink, if the heat sink is detached due to dropping or vibration of the main body, It may cause a short circuit with the conduction part in the body, causing failure, and in the worst case, it may lead to smoke or fire. In some cases, a heat sink alone may not provide a heat dissipation effect.
[0004]
Therefore, recently, as shown in FIG. 3B, the heat sink 30 is coupled with another member, for example, a sheet metal 32 for countermeasures against radiation noise, so that the heat sink is not removed while the heat radiation efficiency is improved. ing.
[0005]
[Problems to be solved by the invention]
In the case of the above-mentioned means, countermeasures are taken for removal of the heat sink and heat dissipation. However, if another member for attaching the heat sink is a conductive material such as for attachment to a radiation noise countermeasure sheet metal, for example, an LSI package. The radiation noise generated from is increased and has an adverse effect.
[0006]
[Means for Solving the Problems]
The present invention relates to an LSI package mounted on a substrate, a heat sink for heat dissipation of the LSI package disposed on the LSI package, a ferrite core surrounding the heat sink, and radiation for fixing the heat sink and the ferrite core to the substrate. It is composed of a noise shielding sheet metal , making it easy to mount by taking measures against heat radiation and suppression of radiation noise at the same time.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the LSI package cooling apparatus of the present invention, both the heat and radiation noise directly generated from the LSI package can be suppressed by arranging the heat sink for cooling the LSI package so as to be surrounded by the ferrite core.
[0008]
By providing the cooling heat sink with a shape for fixing the ferrite core to the radiation noise shielding sheet metal together with the heat sink, a separate part for fixing the ferrite core is unnecessary, and the assemblability is improved. This cooling heat sink has a convex shape, is formed into a required shape by drawing and shearing, and is further provided with a screw fixing hole.
[0009]
【Example】
An embodiment of the present invention will be described with reference to the drawings.
[0010]
In FIG. 1, an aluminum alloy heat sink 1 that passes through a hole 2 a of a doughnut-shaped ferrite core 2 is fastened and fixed to a radiation noise shielding sheet metal 11 obtained by bending an iron plate with screws 12. In addition, the heat sink 1 may be other excellent heat conductivity, for example, copper.
[0011]
The heat sink 1 has a convex shape in which a guide portion 1a having a size that does not rattle the ferrite core 2 through the hole 2a of the ferrite core 2 and a seat 1b on which the ferrite core 2 is placed are provided.
[0012]
Thus, by making the heat sink 1 convex so that the ferrite core 2 can be placed, the heat sink 1 is attached to the radiation noise shielding sheet metal 11 so that no special parts are required, and the ferrite core 2 Can be fixed at the same time.
[0013]
By selecting the material of the ferrite core 2 in accordance with the frequency band of radiation noise generated from the LSI package 16, the effect of suppressing radiation noise can be further increased.
[0014]
Adhesive rubber sheet 15 having excellent thermal conductivity, for example, silicon rubber, is attached to contact surface 14 of heat sink 1, and radiation noise with heat sink 1 mounted on substrate 10 on which LSI package 16 is mounted. The shielding sheet metal 11 is placed and fixed to the electronic device body 3 together with the substrate 10 with screws 17.
[0015]
At this time, it is desirable that the thickness of the rubber sheet 15 is set slightly larger than the gap so that the LSI package 16 and the contact surface 14 can be in close contact even if they are somewhat widened.
[0016]
FIG. 2 is a perspective view of an attachment jig 20 for fixing the heat sink 1 and the ferrite core 2 to the radiation noise shielding sheet metal 11 with screws 12. The mounting jig 20 has a hole 21 for positioning the heat sink 1 and allowing the ferrite core 2 to escape, a guide 22 for positioning the radiation noise shielding sheet metal 11 around the mounting jig 20, and a radiation noise shielding sheet metal. An installation surface 23 is provided for placing 11 in a stable state. First, the heat sink 1 and the ferrite core 2 are inserted into the hole 21 in this order, and the radiation noise shielding sheet metal 11 is placed thereon. Then, the heat sink 1 and the radiation noise shielding sheet metal 11 are fastened and fixed with screws 12. Thereafter, the radiation noise shielding sheet metal 11 with the heat sink 1 and the ferrite core 2 is removed from the mounting jig 20.
[0017]
As a result, the heat and radiation noise generated from the LSI package 16 are radiated through the radiation noise shielding sheet metal 11 via the heat sink 1 with respect to the heat, and the ferrite core 2 disposed around the heat sink 1 with respect to the radiation noise. Therefore, it is possible to take measures against both heat radiation and suppression of radiation noise.
[0018]
【The invention's effect】
The LSI package cooling device of the present invention has the following effects.
[0019]
It is possible to cool an LSI package that emits high heat and is mounted on an electronic circuit board of an electronic device, and to suppress radiation noise.
[Brief description of the drawings]
1A is a cross-sectional view of a heat sink according to an embodiment of the present invention. FIG. 1B is a perspective view of a heat sink according to an embodiment of the present invention. FIG. (B) Cross-sectional view showing another example of a conventional heat sink
DESCRIPTION OF SYMBOLS 1 Heat sink 1a Guide part 1b Seat 2 Ferrite core 2a Hole 3 Electronic equipment main body 10 Board | substrate 11 Radiation noise shielding sheet metal 12 Screw 13 Mounting surface 14 Contact surface 15 Rubber sheet 16 LSI package 17 Screw 20 Mounting jig 21 Hole 22 Guide 23 Installation surface

Claims (3)

An LSI package mounted on a substrate, a heat sink for heat dissipation of the LSI package arranged on the LSI package, a ferrite core surrounding the heat sink, and fixing the heat sink and the ferrite core to the substrate LSI package cooling device comprising a radiation noise shielding sheet metal . 2. The cooling device for an LSI package according to claim 1, wherein the heat sink has a convex shape having a guide portion inserted into a hole of the ferrite core and a seat on which the ferrite core is placed. LSI package cooling more any one of claims 1 or claim 2, characterized in that the ferrite core and the heat sink to simultaneously screwed to the radiation noise shielding sheet metal disposed on the substrate on which the LSI package is mounted How to fix the device.

Images