JPH0531827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvement of a semiconductor device using so-called three-dimensional mounting multi-chip package technology, in which a large number of semiconductor chips are mounted in one package.

[Conventional technology]

Conventionally, in this type of semiconductor device, multiple semiconductor chips (LSI chips) are planarly mounted on multiple wiring boards, and these wiring boards are sequentially arranged side by side in the stacking direction and mounted on another wiring board. It is known to have a configuration in which these components are provided in a single package. To briefly explain such a conventional three-dimensionally mounted multi-chip package using FIGS. Each of these semiconductor chips 1 has a certain function, such as a large-capacity memory, a large-scale logic circuit of a microprocessor, etc. All the chips 1 constitute the functions of the entire semiconductor device. 2 is a plurality of first wiring boards on which a plurality of these semiconductor chips 1 are arranged and fixed, and their functions are interconnected; 3, these first wiring boards are arranged side by side in an upright state; The first and second wiring boards 2 and 3 are the second wiring boards that interconnect the functions of the multiple semiconductor chips 1.
It is packaged by being placed on an insulating substrate 4 along with the above. Here, in the figure, 5a is an electrode (hereinafter referred to as a bump) made of a Pb-Sn alloy formed on each semiconductor chip 1 for electrically and mechanically connecting it to the first wiring board 2 side, and 5b is an electrode (hereinafter referred to as a bump) on each semiconductor chip 1. An electrode (bump) made of Pb/Sn alloy that electrically and mechanically connects the first wiring board 2 to the second wiring board side.
Further, 6 is a wire that electrically connects the second wiring board 3 and the insulating substrate 4, and 7 is an external connection electrode (external pin) for taking out the function of this semiconductor device to the outside.

In a semiconductor device with such a configuration, the PN junctions formed on the main surface of the semiconductor chip 1 are connected to each other by wiring (not shown) made of Al or the like, and the electrical functions of the PN junctions are performed on the same plane as the main surface. The structure is such that it can be taken out from any location. Therefore, if the main surface of the semiconductor chip 1 is placed parallel to and facing the main surface (substrate surface) of the first wiring board 2, the semiconductor chip 1 can be bonded by reflow bonding the bumps 5a placed in the gap. electrically connecting the functions of the chip 1 and the wiring of the first wiring board 2;
At the same time, this semiconductor chip 1 can be fixed onto the first wiring board 2. Wiring for interconnecting the semiconductor chips 1 and interconnection wiring (not shown) are formed in advance on the main surface of the first wiring board 2, so that each semiconductor chip mounted as described above The functions of 1 are connected and combined with each other. As a result, this first wiring board 2 has a plurality of semiconductor chips 1 mounted in this way.
This means that as many functions (subsystems) as there are will be configured.

On the other hand, in the first wiring board 2 on which a plurality of semiconductor chips 1 are mounted, the electrodes 5b arranged on one side of the outer periphery in contact with the main surface (substrate surface) of the second wiring board 3 are subjected to reflow bonding. So, the second
It is arranged vertically on the main surface of the wiring board 3, thereby electrically connecting the first wiring board 2 to the second wiring board 3, and at the same time mechanically fixing it. There is. Then, on the main surface of this second wiring board 3, wiring for interconnecting the first wiring boards 2 and interconnection wiring (not shown) are formed in advance, so that the first wiring mounted on this Board 2
The individual functions (subsystems) above are connected to each other,
It will be combined. Therefore, on this second wiring board 3, all the subsystems of the first wiring board 2, that is, all the individual functions of the large number of semiconductor chips 1 housed in this semiconductor device are mounted and combined. This can be configured as follows.

Further, after mechanically fixing this second wiring board 3 to the insulating board 4 with an adhesive (not shown), the second wiring board 3 is
This is achieved by electrically connecting the function extracting electrode (not shown) formed on the wiring board 3 and the wiring (not shown) formed on the insulating board 4 with a wire 6 made of Au or the like. All functions of the second wiring board 3 are continued to the insulating board 4 side. Since the wiring on this insulating substrate 4 is connected to an external connection electrode (external pin) 7 that extracts the function of this semiconductor device to the outside, the semiconductor chip 1, the bumps 5a, the first wiring board 2, All functions of the semiconductor device are completed through the electrode 5b, the second wiring board 3, the wire 6, and the external pin 7, and can be transmitted to the outside.

Incidentally, on the insulating substrate 4 are a semiconductor chip 1, a first wiring board 2, a second wiring board 3, and a wire 6.
A lid body (not shown) that physically and chemically protects the
Since the device was mounted with a cap on it, this function was not damaged during normal handling, and the device could be operated as a multi-chip packaged semiconductor device.

[Problem that the invention seeks to solve]

By the way, according to the conventional device described above, the first wiring board 2 on which the semiconductor chip 1 is mounted is made of a Pb-Sn alloy provided on one side of the outer periphery of the first wiring board 2 in contact with the substrate surface of the second wiring board 3. Since the second wiring board 3 is fixed in a cantilever manner in an upright state on the substrate surface of the second wiring board 3 by the electrodes 5b, these first wiring boards 2
The mechanical connection strength between the electrode 5b and the second wiring board 3 was weak against force applied from the side where the electrode 5b was not provided, that is, the back side. This is an inevitable feature due to the cantilevered fixed structure, and is susceptible to swinging loads such as vibrations, leading to the disadvantage of low reliability.

On the other hand, if the cross-sectional area of the electrodes 5b is increased in order to increase the mechanical strength, the electrodes 5b arranged on the tangent between the first wiring board 2 and the second wiring board 3 will short-circuit. However, the number of electrodes that can be arranged must be reduced, thereby reducing the number of signal terminals of the subsystem on the first wiring board 2, and as a result, the scale of the subsystem must be reduced. On the other hand, if a large-scale system is assembled into a three-dimensional multi-chip package, the number of electrodes will increase and the cross-sectional area of the electrode 5b will decrease, thereby increasing the mechanical connection strength between the two wiring boards 2 and 3. This caused the problem that the reliability of the system was weakened and reliability decreased.

That is, in such a conventional device, if an attempt is made to increase the mechanical strength between the first wiring board 2 and the second wiring board 3, the reliability of the semiconductor device may decrease or the subsystem of the first wiring board 2 may deteriorate. There is a problem in that the scale of the problem must be reduced, and it is desired that some kind of measures be taken to eliminate these problems.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to obtain a semiconductor device that can be configured into a large-scale system without reducing the reliability of the device.

[Means for solving problems]

A semiconductor device according to the present invention includes a plurality of first wiring boards each having a plurality of semiconductor chips mounted on the board surface, and a board surface on which these wiring boards are arranged in an upright state in parallel in a stacking direction. A second wiring board disposed perpendicular to the wiring board, and an insulating board on which the second wiring board is mounted and fixed and has external connection electrodes,
One side surface of the semiconductor chip mounted on the first wiring board is brought into contact with the surface of the second wiring board on which the first wiring board is erected.

[Effect]

According to the present invention, the cantilevered fixing structure of the first wiring board on which the semiconductor chip is mounted is reinforced by the semiconductor chip whose side surface is in contact with the second wiring board. This makes it possible to increase the mechanical connection strength between the substrates.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

Figures 1a, b, c, and d show an embodiment of the semiconductor device according to the present invention, and in these figures, the same or corresponding parts as those in Figure 3 a, b, and c described above are the same. They are numbered and their explanations are omitted.

Now, according to the present invention, a plurality of semiconductor chips 1, a plurality of first wiring boards 2 each having a plurality of semiconductor chips 1 mounted on a board surface, and a plurality of first wiring boards 2 are arranged in a vertical position. A second wiring board 3 having board surfaces arranged in parallel in the stacking direction in the installed state and disposed perpendicular to the first wiring board 2; and an external connection electrode 7 on which the second wiring board 3 is mounted and fixed. A side surface 1a of the semiconductor chip 1 mounted on the first wiring board 2 is connected to a second wiring board 3 on which the first wiring board 2 is erected.
The feature is that it is configured to be brought into contact with the surface of the substrate.

That is, when mounting the semiconductor chip 1 with the bumps 5a on the first wiring board 2 described above,
At least one is mounted at a position such that its side surface 1a is in contact with the substrate surface of the second wiring board 3.
When one side surface of the first wiring board 2 is brought into contact with and fixed on the second wiring board 3, it is preferable that the side surface 1a of the semiconductor chip 1 described above is also brought into contact with the second wiring board 3. It is something. In this state, if the side surface of the first wiring board 2 is fixed to the second wiring board 3 side with the electrode 5b, the first wiring board 2
An electrode 5 is provided in the center between the side surface and the semiconductor chip side surface 1a.
A fixed state can be obtained by interposing b. Note that since the second wiring board 3 electrically insulates the board surface, the semiconductor chip side surface 1a
and the second wiring board 3 are electrically independent, and their functions are not impaired.

In such a configuration, when force is applied from the surface of the first wiring board 2, the point of force is the central electrode 5b, and the fulcrum is the tangent line that contacts the back surface of the first wiring board 2 and the main surface of the second wiring board 3. And conversely, the first
When a force is applied from the back surface of the wiring board 2, the point of force is also the central electrode 5b, and the fulcrum is a tangent that contacts the back surface of the semiconductor chip 1 and the board surface of the second wiring board 3. The breaking strength at this time depends on the material strength of the central electrode 5b, but since the thicknesses of the semiconductor chip 1 and the first wiring board 2 are approximately the same, the breaking strength is approximately the same against forces from both directions. It will have a mechanical connection strength of approximately In other words, the structure according to the present invention acts so as to be strong against swinging loads such as vibrations.

Therefore, in the structure according to the present invention, the problem of being weak against force in one direction as in the cantilever type is eliminated, and unlike the conventional structure, in order to increase mechanical strength, the cross-sectional area of the electrode 5a is increased. No additional countermeasures are required, and the number of signal terminals of the subsystem on the first wiring board 2 can be increased, thereby making it possible to assemble a large-scale system into a three-dimensionally mounted multi-chip package.

FIG. 2 shows another embodiment of the present invention, in which a plurality of semiconductor chips 1 are used in contact with the second wiring board 3, and its effects can be easily understood. It will be.

Note that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part may be modified and changed as appropriate. For example, in the above-mentioned embodiment, a case was explained in which one second wiring board 3 was mounted on the insulating substrate 4, but a plurality of second wiring boards 3 may be mounted on the insulating board 4. Of course.

Furthermore, in the embodiment described above, the semiconductor chip 1
has been described as a logic circuit LSI chip, but it will be easily understood that it may have other functions such as memory and sensor, and it is not limited to LSI but may also be MSI or SSI. Furthermore, the semiconductor chip 1 may have no active elements and only passive elements such as wiring, resistance, and capacitance are formed, and in addition to the semiconductor chip 1, the first wiring board 2, and the second wiring board 3, there may be coils, Passive elements such as capacitors may be mounted.

〔Effect of the invention〕

As explained above, according to the semiconductor device according to the present invention, a plurality of semiconductor chips, a plurality of first wiring boards formed by mounting these chips on the substrate surface,
With these first wiring boards standing upright, there is a second wiring board that has board surfaces arranged in parallel in the stacking direction and is arranged orthogonally to the first wiring boards, and a second wiring board that is mounted and fixed to the outside. An insulated substrate having connection electrodes is provided, and at least one side surface of a semiconductor chip mounted on a first wiring board is placed on the substrate surface of a second wiring board on which the first wiring board is erected. By making them contact each other, it is possible to increase the mechanical connection strength between the first wiring board and the second wiring board compared to the conventional method, despite the simple and inexpensive structure. It has various excellent effects such as being resistant to loads and improving reliability. According to the present invention, since it is not weak against force in one direction like a cantilever type, there is no need for a structure in which the cross-sectional area of the electrode is increased in order to increase mechanical strength. It is also possible to increase the number of signal terminals in the wiring board subsystem, which has great effects, such as allowing large-scale systems to be assembled into three-dimensionally mounted multi-chip packages.

[Brief explanation of drawings]

1a, b, c, and d are schematic perspective views, front views, side views, and a detailed view of part A thereof showing one embodiment of a semiconductor device according to the present invention, and FIG. 2 is another embodiment of the present invention. FIGS. 3A, 3B, and 3C are a schematic perspective view, a side view, and a detailed view of part B of the conventional example. DESCRIPTION OF SYMBOLS 1... Semiconductor chip, 1a... Side surface, 2... First wiring board, 3... Second wiring board, 4... Insulating substrate, 5a... Bump, 5b... Electrode (bump),
6...Wire, 7...External connection electrode.

Claims (1)

[Claims] 1. A plurality of semiconductor chips, a plurality of first wiring boards formed by mounting these plurality of semiconductor chips on a substrate surface, and a substrate surface on which these first wiring boards are arranged in an upright state in parallel in the stacking direction. at least one second wiring board disposed perpendicularly to the first wiring board; and an insulating board having external connection electrodes on which the second wiring board is mounted and fixed; A semiconductor device characterized in that at least one side surface of a semiconductor chip mounted on a first wiring board is brought into contact with the substrate surface of a second wiring board on which the first wiring board is erected.