JPH06209176A - Heat conduction method - Google Patents

Abstract

PURPOSE:To directly conduct the heat of a high heat generation component like an LSI from the component to a board frame or the like, instead of indirect conduction via a mounting board. CONSTITUTION:Leads 2 of an electric component 1 are inserted into a mounting board in which a square hole 8 conformable to the package size is formed, so as to be buried. From the opposite surface of the mounting board 5, a box type stiffener 9 or a pedestral type stiffener is directly fixed to the package of the electric component 1, by using thermally conductive adhesive agent. Generated heat is directly conducted to a board frame 11 via each stiffener. Since the generated heat from the electric component 1 is directly conducted to the board frame 1, head conduction efficiency is improved, and temperature rise of the board 5 can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat conduction method for mounting a high heat generating electric component such as an LSI on a substrate.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional heat conduction method according to the present invention. In FIG. 5A, 1 is an electric component,
Reference numeral 2 is a lead molded for mounting the electric component 1 on a substrate, 3 is a lead pad for electrically connecting the electric component 1 and the lead 2, and 4 is a molding portion of the lead 2. The lead 2 of the electric component 1 of the flat package is basically shipped in a straight shape without the molding portion 4 of the lead 2. Therefore, conventionally, when the electric component 1 is mounted on the substrate, the lead 2 is molded by using a molding jig as shown in FIG.

FIG. 5B shows an example of a board of the electric component 1. Reference numeral 5 is a mounting board, and 6 is a lead pad for soldering the leads 2.

FIG. 5C shows an electric component 1 mounted on the mounting board 5.
FIG. 6 is a view of a shape of the mounted substrate viewed from the side surface of the mounting substrate 5. Reference numeral 7 is a heat conductive sheet sandwiched between the electric component 1 and the mounting substrate 5. Both sides of the heat conductive sheet 7 are adhesive and have a function of conducting the heat of the electric component 1 to the mounting board 5.

Next, a method of mounting components will be described with reference to FIG. The heat conductive sheet 7 is bonded onto the mounting substrate 5. From above, the electric component 1 shown in FIG. 5A is adhered, and the leads 2 and the lead pads 6 are fixed by soldering or the like.

[0006]

In the component mounting method as described above, the heat generation of the electric component 1 is conducted to the mounting substrate 5 via the lead 2 and the heat conductive sheet 7. However, in recent years, large-scale LSIs and high-speed processing operations are becoming common, and the heat generation per stone reaches several watts, and heat cannot be fully conducted only by the conventional heat countermeasures through the mounting board 5. There is a problem that the temperature of the electric component 1 and the temperature of the mounting substrate 5 increase, and it is difficult to suppress the temperature within the upper limit of the allowable temperature.

The present invention has been made to solve the above problems, and the heat generated from the electric component 1 is transferred to the mounting substrate 5
The purpose is to directly conduct heat to a frame such as an alumina material of the mounting substrate 5 by a member having a good thermal conductivity, without using the interposition.

[0008]

According to the heat conduction method of the present invention, the lead 2 of the electric component 1 is not molded as in the conventional example shown in FIG. Electrical component 1 on mounting board 5 with square holes
After inserting it from the mounting surface side and fixing it by soldering, etc., put a box-shaped heat conduction box that wraps the package of the electric component 1 on a square plate made of a material with good heat conductivity such as aluminum. The constructed box-type stiffener for heat conduction was inserted from the side opposite to the mounting surface of the electric component 1, and the box-type stiffener was bonded to the electric component 1 using a heat conductive adhesive so as to wrap the package of the electric component 1. After that, one of the square plates of the box-type stiffener is fixed to the substrate with a screw, and the opposite side is directly fixed to the substrate frame or the like with a screw or a heat conductive adhesive, so that heat is generated from the electric component 1. The heat can be directly conducted to the substrate frame or the like through the box type stiffener having a good thermal conductivity without passing through the mounting substrate 5.

Further, a pedestal stiffener forming a trapezoidal pedestal that can be fixed with a heat conductive adhesive is formed only on the bottom surface of the package of the electric component 1, and after the electric component 1 is fixed to the mounting substrate 5, the electric component 1 is electrically connected. A thermal conductive adhesive is applied to the pedestal portion of the pedestal stiffener from the side opposite to the mounting surface of the component 1 and is inserted into the pedestal stiffener. The heat generated from the electric component 1 does not directly pass through the mounting substrate 5 by directly fixing the opposite side to the board frame or the like with screws and a heat conductive adhesive. It is designed so that it can be conducted to a board frame or the like via a pedestal type stiffener with good performance.

The box-shaped and pedestal-shaped functions have the same function regarding heat conduction, but the former is applied to the electric component 1 which generates a large amount of heat, and the latter is applied to the electric component 1 which generates a little heat. Selection is required depending on the degree of heat generation of the selected electrical component 1.

[0011]

By adopting the mounting method using the box type stiffener so as to wrap the package of the electric component 1 as described above, the heat generated from the electric component 1 is transferred from the entire surface of the package of the electric component 1 to the box. It acts so that heat can be conducted to the aluminum material frame of the mounting substrate 5 via the mold stiffener.

Further, by adopting a mounting method using a pedestal type stiffener which can be fixed only to the bottom surface of the package of the electric component 1 with a heat conductive adhesive, the heat generated from the electric component 1 is generated from the bottom surface of the package of the electric component 1. Acts to allow heat to be conducted to the aluminum material frame of the mounting substrate 5 via the pedestal stiffener.

[0013]

【Example】

Example 1. FIG. 1 shows an embodiment of the present invention, and 1 to 6 are the same as conventional ones. Reference numeral 8 is a square hole formed through the mounting substrate 5 for inserting the electric component 1, and 9 is a box-type stiffener made of an aluminum plate material. Reference numeral 10 denotes a heat conductive adhesive that adheres and fixes the package of the electric component 1 to the inner surface of the box-type stiffener 9. The heat conductive adhesive 10 is applied to the shaded area in FIG.

2A and 2B are views showing the electric component 1 mounted on the mounting board 5. FIG. 2A is a side view and FIG. 2B is a top view. Reference numeral 11 denotes a board frame of the mounting board 5. The substrate frame 11 is made of a heat conductive material such as aluminum. Reference numeral 12a is a screw for fixing the mounting substrate 5 and the box type stiffener 9 and 12b is a screw for fixing the substrate frame 11 and the box type stiffener 9.

Next, a mounting procedure will be described with reference to FIGS. As shown in FIG. 1, first, the electric component 1 is attached to the square hole 8 of the mounting substrate 5.
To insert. After the insertion, the lead 2 and the lead pad 6 are fixed with solder or the like as shown in FIG. After fixing, as shown in FIG. 1, the box-type stiffener 9 coated with the heat conductive adhesive 10 is inserted into the mounting substrate 5 from the direction opposite to the mounting direction of the electric component 1. FIG. 2A shows the state after the insertion, in which all the package surfaces except the upper surface of the electric component 1 are covered with the heat conductive adhesive 10.
Fixed by adhesion. After the fixing, the box type stiffener 9 and the mounting substrate 5 are fixed by the screw 12a. The fixing by the screws 12a is arranged not mainly for heat conduction but for strengthening the vibration resistance of the mounting substrate 5 and the box-type stiffener 9. The opposite sides of the box-type stiffener 9 are fixed to the substrate frame 11 with the screws 12b and the heat conductive adhesive 10.

Except for the heat passing through the leads 2, most of the heat generated by the components is as shown by the thick arrow in FIG.
Conduction is conducted directly from the box-type stiffener 9 to the board frame 11 without passing through the mounting board 5.

Example 2. In the first embodiment, the mounting board 5
The entire surface of the electric component 1 except the upper surface of the electric component 1 is covered with the box portion of the box-type stiffener 9 in this embodiment.
Is a method of conducting heat only by using the heat conductive adhesive 10 on the bottom surface of the.

FIG. 3 shows an embodiment of the present invention.
1 to 8 and 10 to 12 are the same as in the first embodiment. Thirteen
Is a pedestal type stiffener in which a pedestal for contacting the bottom surface of the electric component 1 is attached on a rectangular plate shape.

FIG. 4 shows an example in which the electric component 1 is mounted on the mounting board 5. FIG. 4 (a) is a side view and FIG. 4 (b).
Is a top view.

Next, the mounting procedure will be described. It is basically the same as that of the first embodiment. However, the portion of the heat conductive adhesive 10 is limited to only the bottom surface of the electric component 1. Pedestal type stiffener 1
3 is fixed to the mounting substrate 5 with the screws 12a, and is also fixed to the substrate frame 11 with the screws 12a and the heat conductive adhesive 10. The heat generation of the electric component 1 does not go through the mounting substrate 5 as indicated by the thick arrow in FIG.
Conducted to 1.

In the above description, the electrical component 1 is the LS.
Although a flat package such as I has been described as an example, it is needless to say that the present invention can be applied to parts such as a transistor having high heat generation.

[0022]

Since the present invention is constructed as described above, it has the following effects.

The package of the high heat-generating electric component 1 is covered with a box type stiffener 9, and the box type stiffener 9 is used.
The heat can be directly conducted to the substrate frame 11 through the. Accordingly, it is possible to prevent the temperature of the electric component 1 and the mounting board 5 from rising.

By using the pedestal type stiffener 13 instead of the box type, heat can be directly conducted to the substrate frame 11. Accordingly, it is possible to prevent the temperature of the electric component 1 and the mounting board 5 from rising. In addition, the second embodiment also has an effect that the processing is easier than the first embodiment.

[Brief description of drawings]

FIG. 1 is an example of a component showing a first embodiment of the present invention.

FIG. 2 is a side view and a top view of the assembly showing the first embodiment of the present invention.

FIG. 3 is an example of a component showing a second embodiment of the present invention.

4A and 4B are a side view and a top view of an assembly showing Embodiment 2 of the invention.

FIG. 5 is a diagram showing an example of a conventional heat conduction method for a mounting board.

[Explanation of reference numerals] 1 electrical component 2 lead 3 lead pad 4 molding part 5 mounting substrate 6 lead pad 7 thermal conductive sheet 8 square hole 9 box type stiffener 10 thermal conductive adhesive 11 substrate frame 12a screw 12b screw 13 pedestal stiffener

Claims (2)

[Claims] 1. A flat package type electric component in which leads for inputting and outputting electric signals are drawn out in parallel and straight from the opposite two sides or four sides of an electric component such as an LSI having a quadrilateral package to the package upper surface,
A lead pad that can be soldered by making a square hole in the part where the electrical component is mounted that matches the shape of the package size of the electrical component, and placing the straight lead of the electrical component on the opposite two or four sides of the square hole as it is. It is composed of a box-shaped stiffener for heat conduction that forms a box-shaped heat conduction box that encloses the package of electrical components on a square board made of aluminum material with good heat conductivity, which is placed on the mounting board. Insert the component into the square hole of the board from the surface where the lead pad is placed, fix the straight lead of the electrical component and the lead pad on the substrate that matches the lead by soldering, etc., and then place the electrical component inside the heat conduction box of the box-type stiffener. Apply a heat conductive adhesive for fixing the contact surface with the package of the After adhering the box-type stiffener to the electrical parts so as to wrap the package, fix one side of the square plate of the box-type stiffener to the mounting board with screws, and directly attach the opposite side to the board frame etc. with screws and thermal conductivity. By fixing with an adhesive, heat generated from electric parts can be directly conducted to a substrate frame or the like via a box type stiffener having good thermal conductivity without passing through a mounting substrate. 2. A trapezoidal pedestal stiffener that comes into contact only with the bottom surface of a package of electric parts fixed to a mounting board is made of a material such as aluminum having good thermal conductivity, and is mounted from the opposite side of the mounting surface of the electric parts. , A pedestal stiffener coated with a heat conductive adhesive for fixing the electrical components to the bottom of the package is inserted into the square holes of the board to fix them to the electrical components, and then a square plate of the pedestal stiffener. The heat conduction method according to claim 1, wherein one of the two is fixed to the substrate with a screw, and the opposite side is directly fixed to the substrate frame or the like with the screw and the heat conductive adhesive.