JP2550879B2 - Semiconductor device mounting structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a mounting structure of a surface mounting type semiconductor device.

[0002]

2. Description of the Related Art Surface-mounting type semiconductor devices are not preferable in terms of high-density mounting because the mounting area for a circuit board is large. Therefore, in recent years, a structure aiming at high density of this kind of semiconductor device has been proposed. FIG. 4 is an example thereof, in which the lead terminal 42 is led out from one side of the package 41 of the semiconductor device 40, and the package 41 is mounted so that the package 41 is oriented in the vertical direction with respect to the circuit board 1 (actually, it is mounted). (Kaihei 2-106842). In this structure, the semiconductor device 4 on the circuit board 1 is certainly
Although the occupied area of 0 is reduced, it is effective for high density,
On the other hand, the height dimension becomes large, and the height is limited in order to reduce the thickness of the structure of the semiconductor device.

For this reason, it has been proposed to stack a plurality of semiconductor devices to increase the density. One of them is as shown in FIG. 5, in which a plurality of packages 51 of the semiconductor device 50 are stacked in close contact with each other, and leads 52 protruding from each package 51 are erected vertically to the circuit board. The wiring board 53 is attached to the circuit board, and the leads 54 of the wiring board 53 with leads are used for mounting on the circuit board (Japanese Patent Laid-Open No. 63-80591). As for the other one, as shown in FIG. 6, a bare semiconductor element 61 in which a semiconductor element is simply covered with a resin is laminated, and electrodes of the upper and lower semiconductor elements 61 are connected in parallel by lead terminals 62, These are connected to a wiring board 63 with lead terminals to form a module, and then mounted on a circuit board using the leads 64 (Japanese Patent Laid-Open No. 64-1269).

[0004]

With this laminated structure, the height is not restricted, but with the former one,
When connecting the lead terminal 52 of each semiconductor device 50 to the wiring substrate 53 with leads, the positional accuracy of the lead terminal 52 is extremely low because the semiconductor devices 50 are stacked, and the manufacturing yield of connection to the wiring substrate 53 is low. Is very bad. Further, there is a problem that automation of the connection is difficult to realize, and therefore the cost is high and the reliability of the connection portion is low. In the latter case, since the same electrodes of a plurality of stacked semiconductor elements 61 are connected to each other by the lead terminal 62, the semiconductor elements are limited to the same semiconductor element, and the semiconductor elements are not sealed, so that the reliability is significantly reduced. There is a problem of doing.

Further, in both cases, since a plurality of semiconductor devices and semiconductor elements are stacked in close contact or close to close contact, the heat generated in each of them affects each other and is likely to be overheated. There is a problem with heat dissipation. While the object of the present invention is to enable high-density mounting,
An object of the present invention is to provide a mounting structure of a semiconductor device that can be easily mounted and has a high heat dissipation effect.

[0006]

According to the mounting structure of the present invention, a plurality of semiconductor devices mounted in a stacked state on a circuit board has a flat package, and a plurality of lead terminals are projected from one side of the package. are provided integrally protruding on the lower surface of the package together to, this projection is the lead end
When the child is connected and mounted on the circuit board, the package turns
Rotate the bottom surface of the package so that it is parallel to the circuit board.
Between the top surface of the road board or the bottom surface of its own package
Above the semiconductor device package that is below itself
The height dimension is equal to the space dimension between the surfaces. example
For example, the first semiconductor device and the second semiconductor device are stacked.
The first semiconductor device on the lower side is mounted on the road substrate
Mounted by connecting multiple lead terminals protruding from the circuit board
The package is not parallel to the circuit board when
The bottom surface of the package and the circuit board
One protrusion with a height equal to the distance between the top of the plate and
And the second semiconductor device on the upper side is the first semiconductor device.
Multiple lead terminals protruding from one side opposite the mounting
Is connected and mounted on the circuit board, the package
Make sure that the lower surface of the package is parallel to the board.
The lower surface of the package and the upper surface of the first semiconductor device package
A protrusion with a height equal to the distance between the surfaces
It is provided. Further, the other side portion of the package of the second semiconductor device may project above the lead terminal of the first semiconductor device.

[0007]

By stacking a plurality of semiconductor devices, the mounting density can be increased, while a plurality of stacked semiconductor devices can be independently mounted on the circuit board. Therefore, the conventional surface mount type semiconductor device can be mounted. It is possible to mount in exactly the same process as. Also, the semiconductor device can be mounted in parallel with the circuit board by the protrusions provided integrally with the package, and a space can be secured between the circuit board and the lower semiconductor device. By utilizing this, it becomes possible to enhance the heat dissipation effect of each semiconductor device.

[0008]

Next, the present invention will be described with reference to the drawings. 1 is a perspective view of a semiconductor device according to a first embodiment of the present invention, and FIG. 2 is a partially exploded perspective view thereof. In these figures,
In the first semiconductor device 10, a plurality of lead terminals 12 are projected in series from one side of the flat rectangular package 11, and each lead terminal 12 is bent and formed in a crank shape. Further, a plurality of, here, two protrusions 13 are integrally formed on the lower surface of the package 11 of the first semiconductor device 10. These projections 13 are configured such that the lower surface thereof is located substantially flush with the lower surface of the tip portion 12a of the lead terminal 12.

The second semiconductor device 20 is also constructed in the same manner, and a plurality of lead terminals 22 are projected in series from one side of the package 21 of the second semiconductor device 20 and bent in a crank shape. Moreover, two protrusions 23 are integrally formed on the lower surface of the package 21. However,
In the second semiconductor device 20, the lead terminal 2
2 is formed so that the length of its bending middle portion is sufficiently long. Specifically, the package 21 of the second semiconductor device 20
The height dimension from the lower surface of the protrusion 23 provided on the lower surface of the first semiconductor device 10 to the lower surface of the tip portion 22a of the lead terminal 22 is substantially equal to the height dimension of the first semiconductor device 10.

When the first and second semiconductor devices are mounted, the first semiconductor device 10 is mounted horizontally on the surface of the circuit board 1 and the tip ends of the lead terminals 12 are provided on the circuit board 1. It is connected to the pattern 2 by soldering or the like. At this time, since the protrusion 13 provided on the lower surface of the package 10 is brought into contact with the surface of the circuit board 1 and the lower surface of the tip portion 12a of the lead terminal 12 is at the same height position as this, the first semiconductor device 10 is It is mounted horizontally on the circuit board 1.

Then, the second semiconductor device 20 is placed on the first semiconductor device 10, and the lead terminals 22 are attached to the circuit board 1.
Solder to the conductive pattern 3. At this time, the protrusion 23
Is abutted on the upper surface of the package 11 of the first semiconductor device 10 and the lead terminal 22 sets the length of the intermediate portion to the length described above, so that the second semiconductor device 20 is in a horizontal state, in other words, Then, it is mounted on the circuit board in parallel with the first semiconductor device 10. In this case, a solder paste having a predetermined thickness is applied to the connection portion of each of the conductive patterns 2 and 3 by screen printing or the like, and the solder is melted by a heating device such as infrared reflow and placed on it. If the method of connecting the lead terminals 12 and 22 is adopted, the first semiconductor device 10 and the second semiconductor device 20 can be simultaneously mounted on the circuit board.

Therefore, according to this mounting structure, the first
Since the flat packages 11 and 21 of the second semiconductor devices 10 and 20 are mounted on the circuit board 1 in the horizontal direction, respectively, the size in the height direction can be reduced even when both semiconductor devices are stacked. This enables high-density mounting without being restricted in the height direction. Incidentally, it goes without saying that the packaging density can be doubled in this embodiment. Even when the first and second semiconductor devices are stacked, the packages 11 and 21 between the package 11 of the first semiconductor device 10 and the circuit board 1 and between the packages 11 and 21 of the first semiconductor device 10 and the second semiconductor device 20. Between each one is a protrusion 1
Since the required intervals are secured by 3, 23, the heat generated in each semiconductor device can be radiated through these intervals, and a cooling effect can be obtained. Further, when mounting on the circuit board 1, it is possible to use the conventional automatic mounting machine for the surface mounting type semiconductor device as it is, so that the mounting cost is low and the reliability of the solder joint is high.
Since the first and second semiconductor devices 10 and 20 are each configured as a resin-sealed semiconductor device,
High reliability such as moisture resistance.

FIG. 3 is a perspective view of a semiconductor device according to a second embodiment of the present invention. This embodiment also shows an example in which the first and second semiconductor devices are laminated, and the same parts as those of the first embodiment are designated by the same reference numerals. In this embodiment, the package 21 of the second semiconductor device 20 mounted in a stacked state on the upper side of the first semiconductor device 10 is larger than the width dimension of the package 11 of the first semiconductor device 10,
In this case, the other side portion 21a of the package 21 of the second semiconductor device 20 is arranged so as to project above the lead terminals 12 of the first semiconductor device 10.

Incidentally, the projections 13 and 23 are integrally provided on the lower surfaces of the packages 11 and 21 of the first and second semiconductor devices, respectively.
It goes without saying that the projections 13 and 23 can secure a space between the circuit board 1 and the first semiconductor device 10 to obtain a heat dissipation effect. In the second embodiment, even if the width dimension of the package 21 of the second semiconductor device 20 is larger than that in the first embodiment, the mounting area can be made substantially the same as that of the first embodiment.

Here, in the first and second embodiments, an example in which two semiconductor devices are stacked is shown, but the same can be applied to the case where three or more semiconductor devices are stacked. Further, the protrusion may be formed separately from the package and attached to the package with an adhesive or an adhesive tape. In this case, even if the height dimension of the lead terminal and the height dimension of the first semiconductor device are different,
By selecting and using the protrusion having an arbitrary height dimension, it becomes possible to mount the semiconductor device always in parallel with the circuit board.

[0016]

As described above, according to the present invention, in a plurality of semiconductor devices mounted in a stacked state, a plurality of lead terminals are projected from one side of a flat package and projections are integrally provided on the lower surface of the package. , The mounting of the semiconductor device is carried out in a stacked state by using the protrusions while keeping its package parallel to the circuit board, so that the mounting density of the semiconductor device can be increased without being restricted in the height direction. At the same time, a plurality of stacked semiconductor devices can be independently mounted on the circuit board, and can be mounted by a conventional automatic mounting machine. Further, since each semiconductor device is resin-sealed, it goes without saying that the reliability such as the moisture resistance of each semiconductor device is not deteriorated. Further, the protrusions provided integrally with the package can secure a space between the circuit board and the lower semiconductor device, and by utilizing this space, the heat dissipation effect of each semiconductor device can be enhanced. . By forming the protrusion integrally with the package, it is possible to set an arbitrary height dimension by forming the protrusion separately without increasing the number of parts. Further, the first semiconductor device connects its lead terminal to the circuit board in a state where the protrusion is in contact with the surface of the circuit board, and the second semiconductor device has the protrusion in contact with the upper surface of the package of the second semiconductor device. By connecting the lead terminal to the circuit board on the side opposite to the lead terminal of the first semiconductor device in the assembled state, the first and second semiconductor devices can be mounted with the mounting area of one semiconductor device, and the mounting density can be increased. In addition to increasing the distance, it is possible to secure a space between the circuit board and the first semiconductor device and a space between the first semiconductor device and the second semiconductor device to enhance the heat dissipation effect. In this case, even if the package of the second semiconductor device is larger than the first semiconductor device, the other side portion is projected above the lead terminal of the first semiconductor device, so that high-density mounting can be performed without increasing the mounting area. It will be possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall structure of a first embodiment of the present invention.

FIG. 2 is a partially exploded perspective view of the first embodiment.

FIG. 3 is a perspective view showing the overall structure of a second embodiment of the present invention.

FIG. 4 is a perspective view showing an example of a conventional mounting structure.

FIG. 5 is a perspective view showing an example of a mounting structure of a conventional laminated structure.

FIG. 6 is a side view showing another example of a conventional mounting board having a laminated structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2, 3 Conductive pattern 10 First semiconductor device 11 Package 12 Lead terminal 13 Protrusion 20 Second semiconductor device 21 Package 22 Lead terminal 23 Protrusion

Claims (3)

(57) [Claims] 1. In a mounting structure for mounting a plurality of semiconductor devices on a circuit board in a stacked state, each semiconductor device has a flat package, and a plurality of lead terminals are projected from one side of the package and A protrusion is integrally provided on the lower surface, and the lead terminal is a circuit
When connected and mounted on a board, the package is mounted on the circuit board.
Of the bottom surface of the package and the circuit board so that they are parallel to each other.
Between the top surface or the bottom surface of your package and
Between the upper surface of the semiconductor device package and the upper surface of the package
A mounting structure of a semiconductor device, wherein the mounting structure is formed to have a height dimension equal to the space dimension of . 2. A first semiconductor device and a second semiconductor device are stacked.
The lower first semiconductor device mounted on the circuit board in layers
A plurality of lead terminals protruding from one side of the circuit board
When mounted on the circuit board,
The bottom of the package so that they are parallel to each other.
Height dimension equal to the spacing dimension between the surface and the top surface of the circuit board
Is integrally provided, and the second semiconductor device on the upper side is
1 a plurality of semiconductor devices protruding from one side opposite to the semiconductor device
When the lead terminals are connected and mounted on the circuit board, the package
Under the package so that the package is parallel to the circuit board.
The lower surface of this package and the package of the first semiconductor device are on the surface.
A protrusion whose height is equal to the distance from the top of the cage
A mounting structure for a semiconductor device, wherein: 3. The semiconductor device packaging structure according to claim 2 , wherein the second semiconductor device package has the other side portion protruding above the lead terminal of the first semiconductor device.