JPS6130425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an external connection line for a semiconductor element that is less affected by thermal stress even when the semiconductor element mounted on a ceramic substrate is rapidly heated for connection to a printed circuit board.

Ceramic substrates are usually used when mounting semiconductor devices on substrates in order to connect them to printed circuits. This is to improve the surface smoothness, heat resistance, heat dissipation, electrical insulation, and dimensional stability of the substrate, and is made of, for example, an alumina ceramic plate. In the conventional substrate shown in FIG. 1, reference numeral 1 indicates a semiconductor element 2 which is a ceramic substrate. On the other hand, the printed circuit board on which such a ceramic board is mounted is often made of glass fiber-reinforced plastic material, which is advantageous in moldability and cost. Copper foil is bonded to the surface, and through holes for the ceramic board are made. It is set up. In FIG. 1, 3 is a printed circuit board, 4 is a copper foil, and 5 is a through hole. Semiconductor element 1 on ceramic substrate 2
and the external connection line 6 are bonded by a thin film or thick film conductor. When connecting the external connecting wire 6 and the semiconductor element 1, place a gold-plated metal stand with a width of 1 to 2 mm, sandwich the solder piece, bring the external connecting wire 6 close together, and pass it through a heating furnace to melt the solder. They are connected by soldering or by melting the solder with a soldering iron. Although the shape of the external connection line 6 is shown as an L-shape when viewed from the side, it may also be shaped to sandwich the U-shaped ceramic substrate 2. When mounting the mounting board 2 of such a semiconductor element 1 on the printed circuit board 3, the external connection wire 6 is passed through the through hole 5 of the printed circuit board 3, and the other side of the mounting board is immersed in a molten solder bath. The copper foil 4 on the circuit board 3 and the external connection wire 6 are fixed. FIG. 17 shows the solder fixing portion. Since the printed circuit board 3 has a relatively large coefficient of thermal expansion when immersed in the solder bath,
Heat from the solder bath is rapidly conducted to the board 3, and a force is applied that bends the left and right sides of the drawing upward. External connection line 6
is fixed due to the solder joint 7, so the thermal stress generated on the printed circuit board 3 is transferred to the external connection wire 6.
This is transmitted to the ceramic substrate 2 through the ceramic substrate 2, causing peeling, wrinkles, and cracks between the ceramic substrate 2 and the semiconductor element 1, and adversely affecting the electrical characteristics of the semiconductor element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an external connection line for a semiconductor device, which overcomes the above-mentioned drawbacks and reduces the effects on the semiconductor device due to stress caused by heat suddenly applied to a printed circuit board.

Embodiments of the present invention shown in the drawings will be described below. FIG. 2 shows the first embodiment of the present invention corresponding to FIG. 1.
In the embodiment, the same reference numerals as in FIG. 1 indicate the same things. 8 is a flexible portion of the external connection line 6 provided according to the present invention, and is a portion that absorbs the influence of warping due to thermal stress. Since the provision of the flexible portion 8 can absorb the sudden thermal stress generated when immersed in the solder bath, even if the printed circuit board 3 warps, it does not affect the ceramic substrate 2 and the semiconductor element 1. The side of the ceramic substrate 2 where it touches the external connection line 6 is designated P1 (there is no need for them to be fixed to each other with adhesive or the like), and one end of the through-hole 5 is the solder fixed part 7. Assuming that the position is a point P2, the position where the bending part 8 is provided is preferably between the points P1 and P2, and the direction of the bending part is on the lower side of the ceramic substrate 2. The external connection wires 6 excluding the bending portion 8 are P1 and P2.
It is preferable to connect them in a straight line. This is because the spacing between the through holes 5 is standardized at the time of manufacturing the printed circuit board, so it is easy to automatically mount the ceramic board 2 and the external connection wire 6 in a position and shape that match that.
This is also because it is not affected by the heat stress mentioned above.

Furthermore, when using an external connection line provided with a flexible portion 8, if another printed circuit board is provided on top of the ceramic substrate 2 with the same dimensions as the conventional one, the flexible portion 8 may come into contact with the copper foil 4 of the printed circuit board 3.
Therefore, an insulating material such as plastic is interposed as shown by the broken line 9 in FIG. Alternatively, in order to further protect the ceramic substrate 2 and the semiconductor element 1, an insulating cap may be provided as indicated by the dashed line 10 in FIG. It is also good to make the height (height) sufficiently high.

Next, in the present invention, as a part for absorbing thermal stress caused by substrate warpage, in addition to providing a flexible part, conductive rubber may be inserted in that part.

In this way, according to the present invention, the effects of thermal stress on a ceramic substrate can be eliminated with an extremely simple configuration, and the probability of producing defective products can be greatly reduced when manufacturing equipment using semiconductor elements.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration for mounting a conventional semiconductor element mounting board on a printed circuit board, FIG. 2 is a diagram showing a first embodiment of the present invention, and FIG. 3 is a modification of FIG. 2. 1... Semiconductor element, 2... Ceramic substrate, 3
...Printed circuit board, 4...Copper foil, 5...Through hole, 6...External connection wire, 7...Solder fixed part, 8...Bending part.

Claims (1)

[Claims] 1. Semiconductor element 1 mounted on ceramic substrate 2
An external connection line 6 is connected to the external connection line of the semiconductor element, which passes through a through hole 5 provided in the printed circuit board 3 and is connected to a circuit on the board. The connecting wire 6 is provided with a bent portion 8 that is bent inwardly near the other external connecting wire, and an electrical insulator 9 is provided between the bent portion 8 of the external connecting wire and the printed circuit board 3. An external connection line for semiconductor devices characterized by: 2 Semiconductor element 1 mounted on Saramic substrate 2
An external connection line 6 is connected to the external connection line of the semiconductor element, which passes through a through hole 5 provided in the printed circuit board 3 and is connected to a circuit on the board. The connection wire 6 is provided with a bending portion 8 that bends inward toward the other external connection wire, and the ceramic substrate 2 and the external connection wire bending portion 8 are provided.
The semiconductor element 1 has a shape that is higher than the height including the
1. An external connection line for a semiconductor device, characterized in that it is provided with a cap 10 that covers the whole of the semiconductor device.