JPH06216491A - Mounting structure of semiconductor package onto printed wiring board - Google Patents

Abstract

PURPOSE:To prevent a defect as an electrical short circuit and the degradation of an electrical insulating property. CONSTITUTION:A semiconductor chip 2 is mounted on one face of a substrate 1, and a thermally melting conductor object 3 is for on the other face of the substrate 1. The semiconductor chip and the thermally melting conductor object 3 are connected electrically, and a semiconductor package 4 is formed. The thermally melting conductor object 3 is thermally melted and bonded to the surface of a printed wiring board 5, the semiconductor package 4 is mounted on the printed wiring board 5, and a spacer 6 used to keep the interval between the printed wiring board 5 and the semiconductor package 4 definite is installed between them. It is possible to ensure the interval corresponding to the thickness of the spacer 6 between the printed wiring board 5 and the semiconductor package 4, and it is possible to prevent the thermally melting conductor object 3 from being spread to the circumference when it is crushed excessively. In addition, the title mounting structure can be cleaned sufficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a semiconductor package having a semiconductor chip such as an IC mounted thereon is mounted on a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device has been formed by mounting a semiconductor package 4 having a semiconductor chip 2 mounted on a printed wiring board 5. As shown in FIGS. 8A and 8B, a semiconductor package 4 has a semiconductor chip 2 such as an IC mounted on one surface of a substrate 1 such as a printed wiring board, and a heat melting type conductor 3 such as solder on the other surface. Is formed in a ball shape, and the semiconductor chip 2 and the heat-melting conductor 3 are electrically connected via a bonding wire 7. Then, the heat-fusible conductor 3 of the semiconductor package 4 is heat-melted and adhered and mounted on the surface of the printed wiring board 5, and the semiconductor package 4 and the printed wiring board 5 are electrically connected to each other, as shown in FIG. A semiconductor device is formed. The distance between the semiconductor package 4 and the printed wiring board 5 of this semiconductor device (indicated by L in the drawing) is defined by the thickness of the heat-melting conductor 3 which is melted and adhered and crushed.

[0003]

However, when the heat-melting conductor 3 of the semiconductor package 4 is heat-melted and adhered and mounted on the printed wiring board 5 as described above, the heat-melting conductor 3 is excessively crushed and is surrounded by the surroundings. There is a risk that the semiconductor package 4 and the printed wiring board 5 may spread and cause an electrical short circuit failure. Further, since the heat-melting type conductor 3 is excessively crushed and the thickness thereof is reduced, the distance between the semiconductor package 4 and the printed wiring board 5 (indicated by L in the figure) is narrowed, and the cleaning with freon or a solvent is insufficient. However, there is a fear that the electrical insulation of the semiconductor device may deteriorate.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a mounting structure of a semiconductor package on a printed wiring board, which can prevent an electrical short circuit defect and an electrical insulation deterioration. It is what

[0005]

According to a mounting structure of a semiconductor package on a printed wiring board according to the present invention, a semiconductor chip 2 is mounted on one surface of a substrate 1 and a heat melting type conductor 3 is mounted on the other surface of the substrate 1. Provided, the semiconductor chip 2 and the heat-melting conductor 3 are electrically connected to form a semiconductor package 4, and the heat-melting conductor 3 is heat-melted and adhered to the surface of the printed wiring board 5 to print the semiconductor package 4. It is characterized in that it is mounted on the wiring board 5 and a spacer 6 is provided between the printed wiring board 5 and the semiconductor package 4 so as to keep the distance therebetween constant.

[0006]

The heat-fusible conductor 3 is heat-melted and adhered to the surface of the printed wiring board 5 to mount the semiconductor package 4 on the printed wiring board 5, and the space between the printed wiring board 5 and the semiconductor package 4 is fixed. Since the spacer 6 is provided for the purpose of ensuring the thickness of the spacer 6 between the printed wiring board 5 and the semiconductor package 4,
It is possible to prevent the heat-melting type conductor 3 from being excessively crushed and spreading to the surroundings. In addition, the washing can be sufficiently performed.

[0007]

EXAMPLES The present invention will be described in detail below with reference to examples. The substrate 1 is formed of a printed wiring board or the like, and a recess 8 for mounting the semiconductor chip 2 is provided in the center of one surface of the substrate 1 and the other surface of the substrate 1 is a ball-shaped heat-melting conductor. Three
Are provided side by side vertically and horizontally at regular intervals. The hot-melt conductor 3 is solder, copper paste, tungsten paste, or the like, which exhibits fluidity when heated and solidifies at room temperature. Then, the semiconductor chip 2 is mounted in the recess 8 of the substrate 1, and the semiconductor chip 2 and the heat-melting conductor 3 are electrically connected via the bonding wire 7 to form the semiconductor package 4. Figure 2
As shown in (a) and (b), a spacer 6 such as a resin molded product or a metal molded product is adhered to the surface of the semiconductor package 4 on which the heat-meltable conductor 3 is formed with a thermosetting adhesive. It is attached by metal bonding with solder or the like.
The spacer 6 is attached to the substrate 1 between the vertical and horizontal rows of the heat-meltable conductor 3, and its thickness is 0.1 mm to 0.3 mm in consideration of good cleaning property and electrical conductivity.
The degree is desirable. The semiconductor package 4 is mounted on the surface of the printed wiring board 5 by heat-melting and attaching the semiconductor package 4 to the semiconductor package 4.
The semiconductor device as shown in FIG. 1 is formed by electrically connecting the printed wiring board 5 and the printed wiring board 5.

By providing the spacer 6 between the semiconductor package 4 and the printed wiring board 5 in this manner, the thickness interval (indicated by L in the figure) of the spacer 6 is provided between the semiconductor package 4 and the printed wiring board 5. When the semiconductor package 4 is mounted on the surface of the printed wiring board 5 by heat-melting and adhering the heat-melting conductor 3 of the semiconductor package 4, the heat-melting conductor 3 is excessively crushed. Can be prevented from spreading around. Further, the cleaning agent can be easily distributed between the semiconductor package 4 and the printed wiring board 5,
It can be sufficiently washed.

FIGS. 4A and 4B show another embodiment of the semiconductor package 4. This semiconductor package 4
The substrate 1 is provided with a mounting hole 9 opening on the surface on which the heat-meltable conductor 3 is provided, and the spacer 6 is mounted by press fitting into the mounting hole 9. The semiconductor device as shown in FIG. 3 is formed by mounting the semiconductor package 4 on the printed wiring board 5 in the same manner as in the above embodiment.

6A and 6B show another embodiment of the semiconductor package 4. This semiconductor package 4
On the surface of the substrate 1 on which the heat-melting conductor 3 is provided, a square annular spacer 6 formed of a plastic plate or the like is adhered by a thermosetting adhesive. This spacer 6
Is attached to the substrate 1 between the vertical and horizontal rows of the heat melting type conductor 3. The semiconductor device as shown in FIG. 5 is formed by mounting the semiconductor package 4 on the printed wiring board 5 in the same manner as in the above embodiment.

[0011]

As described above, according to the present invention, the semiconductor chip is mounted on one surface of the substrate and the heat-melting conductor is provided on the other surface of the substrate to electrically connect the semiconductor chip and the heat-melting conductor. To form a semiconductor package and heat-melt the heat-fusible conductor on the surface of the printed wiring board to mount the semiconductor package on the printed wiring board and to keep the gap between the printed wiring board and the semiconductor package constant. Since the spacer of is provided, it is possible to secure a space of the thickness of the spacer between the printed wiring board and the semiconductor package, and it is possible to prevent the heat melting type conductor from being crushed too much and spreading to the surroundings. It is possible to prevent an electrical short circuit failure due to contact between the mold conductors. Also, by ensuring a constant distance between the printed wiring board and the semiconductor package, it is possible to sufficiently clean the printed wiring board and the semiconductor package, and to prevent deterioration of electrical insulation caused by insufficient cleaning. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2A is a rear view of the semiconductor package shown in FIG.
(B) is a sectional view.

FIG. 3 is a sectional view of another embodiment of the above.

4A is a back view and FIG. 4B is a cross-sectional view of another semiconductor package of the same.

FIG. 5 is a sectional view of another embodiment of the above.

FIG. 6A is a back view and FIG. 6B is a sectional view of another semiconductor package of the same.

FIG. 7 is a sectional view of a conventional example.

FIG. 8A is a rear view of the semiconductor package shown in FIG.
(B) is a sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Semiconductor chip 3 Thermal melting type conductor 4 Semiconductor package 5 Printed wiring board 6 Spacer

Claims (1)

[Claims] 1. A semiconductor chip is mounted on one surface of a substrate, a heat-melting conductor is provided on the other surface of the substrate, and the semiconductor chip and the heat-melting conductor are electrically connected to each other to form a semiconductor package. A printed wiring formed by mounting a semiconductor package on a printed wiring board by heat-melting and attaching a heat-melting type conductor to the surface of the wiring board, and providing a spacer between the printed wiring board and the semiconductor package to keep the spacing constant. Mounting structure of semiconductor package on board.