JP2000082768A - Mounting of heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mounting a heat sink, which makes a stable installation of a heat sink possible and allows bypass capacitors to be effectively disposed for an integrated circuit package. SOLUTION: A method for mounting a heat sink includes an integrated circuit package 1 mounted on one face of a printed wiring board 2, a heat sink 3 on the integrated circuit package 1, and a plate 4 which is on the other face of the printed wiring board 2 which is to be screwed with the heat sink 1 so as to hold the printed board 2 in between with the heat sink 1. The plate 4 is constituted of projecting sections 4a formed with screw holes 4b and a frame section 4c which stays back inward from the projecting sections 4a. In a space on the printed wiring board 2 demarcated by the frame sections' staying back from the projecting sections 4a, many bypass capacitors are mounted close to the integrated circuit package 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink mounting method, and more particularly to a heat sink mounting method for a BGA (Ball Grid Array) type integrated circuit package, and more particularly to a structure of a heat sink fixing plate.

[0002]

2. Description of the Related Art As power consumption increases due to the speeding up of integrated circuit packages, the internal temperature of a semiconductor during operation increases. If the integrated circuit package exceeds its operation guarantee temperature, it is more likely that the integrated circuit package will not operate normally or be broken.

[0003] Therefore, in order to cool the integrated circuit package, a heat sink is generally provided on the integrated circuit package to enhance the air cooling effect. Usually, the size of the heat sink is increased in proportion to the power consumption of the integrated circuit package.

In particular, on a BGA type integrated circuit package,
When attaching a large and heavy heat sink, the heat sink is fixed to the opposite side of the heat sink across the printed wiring board to reduce the load on the solder balls that electrically connect the printed wiring board and the integrated circuit package. The plate is arranged, and the heat sink and the heat sink fixing plate are screwed together so as to sandwich the printed wiring board using screws with springs penetrating the printed wiring board.

[0005] The heat sink fixing plate has a rectangular frame shape, and screw holes into which the spring-loaded screws are screwed are formed at four corners of the frame portion.

[0006]

However, the above-mentioned prior art has the following problems.

A first problem is that noise cannot be sufficiently attenuated for a BGA type integrated circuit package which is fast and consumes a large amount of power.

The first reason is that as power consumption increases due to an increase in the operating frequency of an integrated circuit package, it is necessary to increase the size of the heat sink and the heat sink fixing plate, and the heat sink and the plate for fixing the heat sink are arranged outside this plate. This is because it becomes difficult to mount the bypass capacitor close to the integrated circuit package.

The second reason is that when the mounting position of the bypass capacitor is far from the integrated circuit package, the effect of noise attenuation is reduced due to the stray capacitance of the pattern.

It is an object of the present invention to stably fix a heat sink and effectively use a bypass capacitor for an integrated circuit package even when the size of the heat sink needs to be increased due to an increase in the speed of the integrated circuit package. It is to provide a heat sink mounting method that can be arranged.

[0011]

According to the present invention, there is provided a heat sink mounting system comprising: an integrated circuit package mounted on a printed wiring board; a heat radiating means provided on the integrated circuit package; An engaging portion is provided on the opposite side of the heat radiating means and engages with the heat radiating means so as to sandwich the printed wiring board, and a frame portion extending backward from the engaging portion and extending backward. Fixing means, and noise attenuating means disposed on the printed wiring board in a space defined by the frame portion being receded from the engaging portion of the fixing means in proximity to the integrated circuit package; Having.

According to the present invention, by improving the structure of the means for fixing the heat radiating means to the printed wiring board, particularly in mounting a BGA (Ball Grid Array) type integrated circuit package, a bypass capacitor or the like can be used. The noise attenuating means can be arranged closer to the integrated circuit package, and the noise attenuating ability can be made to function more effectively. Furthermore, it is possible to arrange more noise attenuating means for one integrated circuit package.

Therefore, according to the present invention, even if the operating frequency of the integrated circuit package is high and it is necessary to attach a large-sized heat radiating means to the integrated circuit package, it is sufficient for the integrated circuit package. The noise attenuation ability can be obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described.

In a preferred embodiment of the heat sink mounting method of the present invention, a heat radiating means (heat sink 3 in FIG. 1) attached to an integrated circuit package (1 in FIG. 1) is mounted on a printed wiring board (2 in FIG. 1). To fix against
It is provided on the opposite side of the heat dissipation means across the printed wiring board,
An engaging portion (a projecting portion 4a in which a screw hole 4b in FIG. 3 is drilled) that engages with the heat radiating means so as to sandwich the printed wiring board;
A frame portion that retreats and extends inward from the engagement portion (4c in FIG. 3).
(A plate 4 in FIG. 1)
Having.

On the printed wiring board, the integrated circuit package is brought as close as possible to a space defined by the frame portion retreating from the engaging portion of the fixing means and extending therefrom. (Bypass capacitor 8 in FIG. 3).

In a preferred embodiment of the heat sink mounting method of the present invention, electrode pads or pins provided in the integrated circuit package are arranged in a grid.
In other words, the heat sink mounting method of the present invention is a BGA
The present invention is suitably applied to mounting of a semiconductor integrated circuit package or a PGA (Pin Grid Array) integrated circuit package.

In a preferred embodiment of the heat sink mounting method according to the present invention, the frame of the fixing means for fixing the heat radiating means is located inside the grid formed by the electrode pads or pins of the integrated circuit package, and The fixing means is configured such that the part is located outside the grid. In some cases, the fixing means is configured such that the grid is accommodated in the frame.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the embodiment of the present invention described above, an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an assembly diagram for explaining a heat sink mounting method according to an embodiment of the present invention. FIG.
It is sectional drawing of FIG. FIG. 3 is a plan view in which some of the elements shown in FIG. 1 are omitted.

Referring to FIGS. 1 to 3, a BGA (Ball Grid Array) type integrated circuit package 1 is electrically connected to one surface of a printed wiring board 2 via solder balls 6 (BGA mounting), and integrated. A heat sink 3 is in contact with the upper surface of the circuit package 1 via a heat conductive buffer material 5.

On the other surface of the printed wiring board 2, a plate 4 is arranged. In particular, referring to FIGS. 1 and 3, the plate 4 has a protrusion 4 a formed at four corners thereof so as to protrude outside the plate 4, a screw hole 4 b formed at each of the protrusions 4 a, and a protrusion. And a rectangular frame portion 4c formed to recede inside the plate 4 from the hole 4a or the screw hole 4b. The screw holes 4b are formed at positions corresponding to screw holes (not shown) formed at four corners of the heat sink 3.

The protruding portion 4a or the screw hole 4b of the plate 4 is formed so as to be located outside the grid of the solder balls 6 or the electrode pads when the heat sink 3 is fixed, and the frame portion 4c is formed on the integrated circuit package 1. Is formed so as to be located inside from the solder ball connection position. This prevents excessive pressure from being applied to the solder balls 6 and the electrode pads of the integrated circuit package 1 or the printed wiring board 2 when the mounting screws (spring screws 7) of the heat sink 3 are tightened.

When the heat sink 3 is fixed, a spring-loaded screw 7 is inserted into the screw hole 4b of the plate 4 and the screw hole (not shown) of the heat sink 3 through a hole formed in the printed wiring board 2. Screw them together. As a result, the heat sink 3 and the plate 4 are fixed to each other so as to sandwich the printed wiring board 2, and the heat sink 3 is attached to the printed wiring board 2 as compared with the case where the heat sink 3 is simply adhered on the integrated circuit package 1. It is fixed more stably.

Furthermore, on the printed wiring board 2, a rectangular frame portion 4c is extended from the projecting portion 4a or the screw hole 4b to the inside of the plate 4 so as to extend into the space defined. Is mounted. If necessary, the bypass capacitors 8 are mounted on both sides of the printed wiring board 2. The bypass capacitor 8 is electrically connected between the power supply terminal of the integrated circuit package 1 and the ground, and absorbs power supply current noise supplied to the integrated circuit package 1.

Next, the function of the heat sink mounting method will be described by taking as an example the case where the power supply current supplied to the integrated circuit package 1 fluctuates due to switching.
Referring again to FIGS. 1 to 3, in this case, for example, the electric charge stored in the bypass capacitor 8 is
Through the above pattern, it is supplied to the integrated circuit package 1 in a very short time. The reason is that the bypass capacitor 8 is arranged close to the power supply terminal of the integrated circuit package 1. Thus, the reliability of the operation of the integrated circuit package 1 is improved.

[0027]

The effects of the present invention will be described. A first effect is that noise attenuation means such as a bypass capacitor can be arranged closer to the integrated circuit package. As a result, the stability of the operation of the integrated circuit package is improved. A second effect is that the large and heavy heat radiating means is stably fixed to the printed wiring board.

[Brief description of the drawings]

FIG. 1 is an assembly diagram for explaining a heat sink mounting method according to an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a plan view in which elements shown in FIG. 1 are partially omitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Integrated circuit package 2 Printed wiring board 3 Heat sink 4 Plate 4a Projection part 4b Screw hole 4c Frame part 5 Heat conductive buffer material 6 Solder ball 7 Screw with spring 8 Bypass capacitor

Claims (4)

[Claims] An integrated circuit package mounted on a printed wiring board; a radiator provided on the integrated circuit package; and a printed circuit provided on the opposite side of the radiator with the printed wiring board interposed therebetween. Fixing means, comprising: an engaging portion that engages with the heat radiating means so as to sandwich the wiring board; and a frame portion that retreats and extends inward from the engaging portion. A noise attenuating means disposed in the space defined by the frame part being retracted from the engagement part of the fixing means, in close proximity to the integrated circuit package. Heat sink mounting method. 2. The heat sink mounting method according to claim 1, wherein the electrode pads or pins of the integrated circuit package are arranged in a grid. 3. The frame part is located inside a grid formed by electrode pads or pins provided in the integrated circuit package, and the engagement part is located outside the grid. Item 2. A heat sink mounting method according to Item 2. 4. A printed circuit board provided on the opposite side of the heat radiating means for fixing the heat radiating means provided on the integrated circuit package to the printed wiring board, and holding the printed wiring board therebetween. An engaging portion that engages with the heat dissipating means, and a frame portion that retreats and extends inward from the engaging portion, wherein the frame portion is disposed on the printed wiring board from the engaging portion. In the space defined by the retreat,
A plate for fixing a heat radiating means, wherein the noise attenuating means can be arranged close to the integrated circuit package.