JPH11340659A - Semiconductor device and its mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of possibilities for imperfect connections between the terminals of a substrate and a motherboard in the case of heat generation of a semiconductor module, by bending a flexible substrate mounting a semiconductor module so as to lift the semiconductor module, and connecting the substrate with the motherboard. SOLUTION: A substrate 2 which has a semiconductor module 1 mounted is further mounted on a flexible substrate 3 for connection. This substrate 3 is bent inside and connected with a motherboard 5, while lifting the semiconductor module 1. Thus, a space is formed between the substrate 2 and the motherboard 5. In other case, the flexible substrate 3 connected with the substrate 2 mounting the semiconductor module 1 is bent outside and connected with the mother board 5 while lifting the module 1. Thus, a space is formed between the substrate 2 and the motherboard 5. As a result, direct contact of the substrate 2 and the motherboard 5 is avoided, and heat generated from the semiconductor module is prevented from directly traveling to the motherboard.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a connection flexible substrate and a method for mounting the same.

[0002]

2. Description of the Related Art Conventionally, in mounting a semiconductor device, first, a semiconductor module is mounted on a substrate such as a ceramic, and the substrate on which the semiconductor module is mounted is directly mounted on a motherboard.

However, this mounting method has a problem in that heat generated from the semiconductor module is transmitted to the motherboard through the substrate, and as a result, reliability is reduced due to poor connection between terminals due to heat generated by the motherboard.

[0004]

Therefore, there has been a strong demand for a semiconductor device which does not cause a connection failure between the substrate and the terminal of the motherboard even if heat is generated from the semiconductor module.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in response to such a demand. That is, the semiconductor device of the present invention is characterized in that a semiconductor module is mounted on a flexible substrate, directly or via another substrate, and the flexible substrate is connected to a motherboard by bending the semiconductor module to lift the semiconductor module. Is what you do.

Further, in the method of mounting a semiconductor device according to the present invention, a step of mounting a semiconductor module on a substrate, a step of connecting a flexible substrate to two opposing sides of the substrate with the semiconductor module interposed therebetween, And bending the flexible board so as to lift the flexible board, and connecting the flexible board to the motherboard while maintaining this state.

Further, the method of mounting a semiconductor device according to the present invention
A step of mounting the semiconductor module substantially at the center of the flexible substrate directly or via another substrate; and a step of bending the flexible substrate so as to lift the semiconductor module and connecting the flexible module to the motherboard while maintaining this state. It is characterized by the following.

FIG. 1 is a schematic perspective view showing an embodiment of the semiconductor device of the present invention, FIG. 2 is a schematic plan view thereof, and FIG. 3 is a schematic sectional view thereof. In these FIGS. 1 to 3, 1 is a semiconductor module, 2 is a substrate, 3 is a connection flexible substrate, and 4 is a terminal for connection to a motherboard, which may be a terminal with solder.

FIGS. 4 and 5 are schematic sectional views showing an embodiment of a method for mounting a semiconductor device according to the present invention.
In FIG. 5, reference numeral 5 denotes a motherboard.

The present invention will be described according to the embodiment of the present invention shown in FIGS. The semiconductor device of the present invention is shown in FIGS.
As shown in FIG. 3, a connection flexible substrate 3 is connected to a substrate 2 on which a semiconductor module 1 is mounted. According to the semiconductor device mounting method of the present invention, this semiconductor device is connected to the motherboard by bending the connecting flexible substrate so as to lift the semiconductor module, as shown in FIGS. 4 and 5. A space can be created between the substrate 2 on which the semiconductor module is mounted and the motherboard, so that heat generation of the semiconductor module can be prevented from being directly transmitted to the motherboard.

In the present invention, the substrate on which the semiconductor module is mounted is not particularly limited. For example, a substrate having good and stable contact with the semiconductor module, such as a ceramic substrate, is used. Such a substrate has a small coefficient of thermal expansion and a value close to the coefficient of thermal expansion of the semiconductor module. Therefore, even if the temperature rises, the problem of poor connection between terminals does not occur.

Further, the connection flexible substrate used in the present invention can be designed in consideration of the effect of temperature rise for connection with the semiconductor module mounting substrate, and even if heat is generated by the semiconductor module. In addition, the problem of poor connection between the semiconductor module mounting board and the connection flexible board can be avoided. For example, for the extraction of the signal line, the extraction from a place where the wiring density of the semiconductor module mounting substrate is not so strict can be used.

On the other hand, since a resin having a large coefficient of thermal expansion is used in the motherboard, if the substrate on which the semiconductor module is mounted is brought into direct contact and connected, when the semiconductor module generates heat, the connecting portion of the motherboard will rise in temperature. As a result, a problem of poor connection between the terminals may occur. However, according to the present invention, the heat generation of the semiconductor module is not directly transmitted to the connection portion of the motherboard, and the rise in the temperature of the connection portion of the motherboard and the accompanying thermal expansion are prevented. Can be avoided.

FIGS. 1 to 3 show an example in which a symmetrical connection flexible substrate in which the connection terminals to the motherboard are branched into four is used. The number of branches can be arbitrarily selected as needed, and the shape may be asymmetric.The present invention relates to a case where a connection flexible substrate is connected to a substrate on which a semiconductor module is mounted. In addition, the present invention broadly encompasses those which have a space between the board and the motherboard and can be prevented from being in direct contact by mounting the semiconductor module on the motherboard so that the flexible board for connection is bent to lift the semiconductor module.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be specifically described based on examples.

Embodiment 1 The semiconductor device of the present invention shown in FIG. 1 was mounted on a motherboard as shown in FIG. In FIG. 4, the substrate 2 on which the semiconductor module 1 is mounted is further mounted on the connection flexible substrate 3, and the connection flexible substrate is bent inward to connect the semiconductor module 1 to the motherboard 5 so that the substrate 2 is lifted.
And a space between the motherboard 5 and the main body. Thus, the board 2 and the motherboard 5 are prevented from directly contacting each other,
This prevents the heat generated by the semiconductor module from being transmitted directly to the motherboard. As a result, it was possible to avoid the occurrence of poor connection between the terminals.

Example 2 As in Example 1, the semiconductor device of the present invention shown in FIG. 1 was mounted on a motherboard as shown in FIG. In FIG. 5, the semiconductor module 1
Connection flexible board 3 connected to board 2 on which is mounted
Is bent to the outside and connected to the motherboard 5 so as to lift the semiconductor module 1, so that a space is provided between the substrate 2 and the motherboard 5.

Thus, the direct contact between the substrate 2 and the motherboard 5 is prevented, so that the heat generated by the semiconductor module is not directly transmitted to the motherboard. As a result, it was possible to avoid the occurrence of poor connection between the terminals.

[0019]

According to the present invention, since the heat generated from the semiconductor module is not directly transmitted to the motherboard, the occurrence of a connection failure due to the heat generated by the motherboard is prevented, and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a semiconductor device of the present invention.

FIG. 2 is a plan view showing one embodiment of a semiconductor device of the present invention.

FIG. 3 is a cross-sectional view showing one embodiment of the semiconductor device of the present invention.

FIG. 4 is a cross-sectional view showing one embodiment of a method for mounting a semiconductor device according to the present invention.

FIG. 5 is a sectional view showing another embodiment of the semiconductor device mounting method of the present invention.

[Explanation of symbols]

1 ... semiconductor module, 2 ... substrate, 3 ...
Flexible board for connection, 4 ... Terminal for connection to motherboard or terminal with solder, 5 ... Motherboard.

Claims (3)

[Claims] 1. A semiconductor device comprising: mounting a semiconductor module on a flexible substrate directly or via another substrate; and bending the flexible substrate so as to lift the semiconductor module and connecting the flexible substrate to a motherboard. . 2. A step of mounting a semiconductor module on a substrate, a step of connecting a flexible substrate to two opposing sides of the substrate with the semiconductor module interposed therebetween, and a step of bending the flexible substrate to lift the semiconductor module. And connecting to the motherboard while maintaining this state. 3. A step of mounting a semiconductor module at substantially the center of a flexible substrate directly or via another substrate, and bending the flexible substrate so as to lift the semiconductor module and connecting the flexible module to a motherboard while maintaining this state. And mounting the semiconductor device.