JPH0964274A - Method of replacing and relieving electronic equipment and faulty cob type semiconductor device mounted onit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace and relieve a faulty COB type semiconductor device connected to a wiring board, by providing a spare electrode pad for mounting a second semiconductor device, in the specified position on the wiring electrically connected to the COB type semiconductor device of the wiring board. SOLUTION: For an SIMM board, 10, nine pieces of COB type semiconductor devices 1 are mounted on one sheet of wiring board 2. As a method of replacing it with other semiconductor device thereby relieving it in case that trouble occurs in the COB type semiconductor device 1 mounted on the SIMM board 10, the wiring 3 between the wiring board bonding pad and the land in the faulty COB type semiconductor device to be replaced is cut. Then, other packaged semiconductor device is put on the faulty COB type semiconductor device 1, and the lead is soldered to the land. Hereby, it follows that the packaged semiconductor device operates in place of the faulty COB type semiconductor device 1, and that the operation of the SIMM board can be performed normally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a wiring board on which one or more semiconductor devices are mounted,
In particular, the present invention relates to a technique effectively applied to an electronic device having a wiring board on which a COB (Chip On Board) type semiconductor device is mounted.

[0002]

COB mounted on a wiring board of an electronic device
Type semiconductor device, a plurality of semiconductor chips are directly attached to one wiring board on which various elements such as resistors and capacitors are mounted, and each semiconductor chip is connected to the wiring of the wiring board by wire bonding. It is sealed with.

There is also a wireless bonding method in which a semiconductor chip is connected to the wiring of a wiring board by using bumps without using wire bonding.

By using this COB type semiconductor device, the number of manufacturing steps can be reduced as compared with an electronic device which is manufactured by mounting the packaged semiconductor device on a printed wiring board, and an inexpensive electronic device can be manufactured.

This COB type semiconductor device has been mainly used for electronic equipment which requires low cost.

[0006]

SUMMARY OF THE INVENTION As a result of studying the above prior art, the present inventor has found the following problems.

In an electronic device having a wiring board on which a conventional COB type semiconductor device is mounted, one or a plurality of semiconductor chips are directly attached to the printed wiring board and resin-sealed. The semiconductor device has an integrated structure.

Therefore, an electronic device having a plurality of semiconductor devices for memories, such as SIMM (Single In-Line), is used.
When a COB type semiconductor device is mounted on a (Memory Module) substrate, if even one of the COB type semiconductor devices on the substrate has a defect, the defective COB type semiconductor device cannot be removed from the substrate and replaced. Therefore, there is a problem in that all elements such as resistors and capacitors and other semiconductor devices that are not defective are treated as defective.

As a result, the more COB type semiconductor devices are mounted, the higher the defect rate and the lower the yield, so that a memory module or the like which requires a plurality of semiconductor devices on one wiring board. It was rarely used in electronic devices.

Further, by stacking another semiconductor device such as a memory or a processor packaged on the COB type semiconductor device, the capacity of the memory or the processing capacity can be increased in a small space. We have found that high-density mounting is possible.

An object of the present invention is to provide a technique capable of replacing and repairing a defective COB type semiconductor device connected to a wiring board.

Another object of the present invention is to provide a technique capable of high-density mounting of electronic equipment.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0014]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In an electronic device having a wiring board on which one or more COB type semiconductor devices are mounted, the wiring board is packaged at a predetermined position on a wiring electrically connected to the COB type semiconductor device. And a spare electrode pad for mounting the second semiconductor device.

In addition, in an electronic device having a wiring board on which one or more COB type semiconductor devices are mounted, the wiring board includes a first wiring electrically connected to the COB type semiconductor device, and A second wiring electrically connected to the second semiconductor device and a spare electrode pad for mounting the second semiconductor device are provided at predetermined positions on the second wiring.

[0017]

According to the above-mentioned means, in an electronic apparatus including a wiring board on which one or a plurality of COB type semiconductor devices are mounted, the wiring board is a wiring electrically connected to the COB type semiconductor device. By providing the second semiconductor device mounting auxiliary electrode pad packaged in a predetermined position above, when a semiconductor device in the wiring board has a defect, it is packaged instead of the defective semiconductor device. Since a normally operating semiconductor device can be mounted by connecting it to the spare electrode pad, a defective COB type semiconductor device connected to the wiring board can be replaced and repaired.

In addition, in an electronic device including a wiring board on which one or more COB type semiconductor devices are mounted, the wiring board includes a first wiring electrically connected to the COB type semiconductor device, and A second wiring electrically connected to the second semiconductor device, and a spare electrode pad for mounting the second semiconductor device at a predetermined position on the second wiring (a position where it can be connected to a lead of the second semiconductor device). Since the semiconductor device such as the memory or the processor can be mounted on the COB type semiconductor device in a small space by including the above, the electronic device can be mounted at high density.

The structure of the present invention will be described below together with embodiments.

In all the drawings for explaining the embodiments, parts having identical functions are given same symbols and their repeated explanation is omitted.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an electronic device of an embodiment of the present invention, a SIM
The M substrate will be described below.

(Embodiment 1) FIG. 1 is a plan view of a SIMM substrate, which is an embodiment of the present invention, as seen from above.

FIG. 2 is a view showing one COB type semiconductor device mounted on the wiring board shown in FIG. 1 and its peripheral wiring. FIG. 2 (a) is a plan view and FIG. 2 (b). Is Figure 2
The side view seen from the X direction of (a) is shown. The wiring pattern of the wiring board 2 and various elements such as resistors are not shown.

FIG. 3 shows the COB semiconductor device before resin sealing and the wiring 3 around it.

1 to 3, 1 is a COB type semiconductor device, 1a is a semiconductor chip, 2 is a wiring substrate, 3 is wiring,
3a is an electrode pad connected to a semiconductor chip, 4 is a land (spare electrode pad), and 10 is a SIMM substrate.

As shown in FIG. 1, the SIMM substrate 10 of this embodiment has nine COB type semiconductor devices 1 mounted on a single wiring substrate 2, and FIGS. 2 (a) and 2 (b). As shown in FIG. 3, on each wiring 3 around the COB type semiconductor device 1, a packaged semiconductor device mounting land 4 (with solder) is provided.

The land 4 is provided at a position where it can be connected to a lead of a packaged semiconductor device described later.

As shown in FIG. 3, the SIMM substrate 10 in this embodiment has the semiconductor chip 1a (for memory) fixed with an adhesive or the like, and then bonded with a wire to bond the electrode pad of the semiconductor chip 1a to the wiring board. The pads 3a are electrically connected. After that, resin or the like is sealed as shown in FIG. 2 to obtain the product shown in FIG.

Next, the SIMM substrate 1 of this embodiment described above
When a defect occurs in the COB type semiconductor device 1 mounted on the 0, the other semiconductor device (COB type semiconductor device 1
A method of substituting a semiconductor device designed with a circuit equivalent to the above) and repairing will be described with reference to FIG.

In this alternative repairing method, first, a defective C
A step of disconnecting the wiring between the wiring board bonding pad 3 a and the land 4 in the OB type semiconductor device 1 is performed.

For example, as shown in FIG. 4 (a), this is cut at the wiring cutting location 7 by using a blade or a laser.

Since the purpose of this step is to make the semiconductor chip 1a in the COB type semiconductor device 1 inoperable, another method may be used as long as the operation of the semiconductor chip 1a can be completely stopped.

After that, as shown in FIG. 4B, a step of mounting another packaged semiconductor device 20 on the defective COB type semiconductor device 1 and soldering its lead to the land 4 is performed. To do.

As a result, the packaged semiconductor device 20 operates in place of the defective COB type semiconductor device 1, and the SIMM substrate operates normally.

Therefore, one or more COBs
In an electronic device including a wiring board on which a semiconductor device of the type is mounted, the wiring board is packaged at a predetermined position on a wiring electrically connected to the COB type semiconductor device for mounting a second semiconductor device. By providing a spare electrode pad, when a semiconductor device in the wiring board becomes defective, a normally operating semiconductor device that is packaged is connected to the spare electrode pad instead of the defective semiconductor device. The defective COB type semiconductor device connected to the wiring board can be replaced and repaired.

(Embodiment 2) Next, in the SIMM substrate 10 of this embodiment, a packaged semiconductor device designed with a circuit equivalent to the COB semiconductor device 1 and packaged is mounted on the COB semiconductor device 1 in a stacked manner. The case will be described.

FIG. 5 is a view for explaining the SIMM substrate 10 in which the packaged semiconductor devices are stacked and mounted on the COB type semiconductor device 1, and FIG.
FIG. 5B is a plan view showing one COB type semiconductor device mounted on the substrate 10 and its peripheral wiring, and FIG.
The side view seen from the X direction of (a) is shown.

FIG. 6 is a diagram for explaining the signal wirings connected to the COB type semiconductor device 1 and the packaged semiconductor device (so-called resin-sealed semiconductor device).

In FIGS. 5 and 6, 20 is a packaged semiconductor device, and A to V are signal lines.

The SIMM substrate 10 of this embodiment is shown in FIG.
(A), as shown in FIG. 5 (b), the packaged semiconductor device 20 is mounted on the COB type semiconductor device 1 while the COB type semiconductor device 1 is operating (without disconnection), and As shown in FIG. 6, a RAS (Row A Address Strob) signal wiring and a CAS (Col
umnAddress Strob) Each has two lines of signal wiring.

Here, the COB type semiconductor device 1 and the packaged semiconductor device 20 are replaced by Hitachi D-RAM, H.
Taking the case of using M514100B as an example, among the signal wirings A to V in the COB type semiconductor device 1 of the present embodiment shown in FIG. 6, D is the RAS signal wiring of the COB type semiconductor device 1 and E is the package. -Fused semiconductor device 20
RAS signal wiring, and this E is not electrically connected to the COB type semiconductor device 1.

Further, S is the CAS of the COB type semiconductor device 1.
A signal wiring, R is a CAS signal wiring of the packaged semiconductor device 20, and this R is also not electrically connected to the COB type semiconductor device 1.

Therefore, when the packaged semiconductor device 20 is stacked and mounted on the COB type semiconductor device 1, the leads corresponding to the lands 4 connected to the D and S signal wirings and the corresponding lands 4 are mounted. The leads that do not have the same are left empty (not connected), and the signal wirings of the other two semiconductor devices are bonded and shared.

As a result, the RAS signal wiring (D, E) and the CAS signal wiring (S, S,
By selecting R) and inputting a signal, each can be operated separately, the memory capacity can be doubled in a small space, and high-density mounting of the SIMM board can be realized.

Although the D-RAM is taken as an example in this embodiment, the same can be applied to the S-RAM by providing two CS (Chip Select) signal lines.

Further, by providing wirings (first wirings, second wirings) dedicated to the upper and lower semiconductor devices in the electronic equipment, separate semiconductor devices (for example, two processors) which are not connected can be mounted. Since the processing capacity can be doubled in a small space, high density mounting of electronic devices becomes possible.

Further, separate semiconductor devices (for example, a memory and a processor) having upper and lower operations can be mounted in the same manner as described above, and likewise, high density mounting of electronic equipment can be achieved, which is more compact. Various electronic devices can be designed.

As described above, the invention made by the present inventor is
Although the specific description has been given based on the embodiment, the present invention is not limited to the SIMM board (memory module) shown in the embodiment, and various modifications can be made without departing from the scope of the invention. Of course.

[0049]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

The defective COB type semiconductor device connected to the wiring board can be replaced and repaired.

Further, high density mounting of electronic equipment becomes possible.

[Brief description of drawings]

FIG. 1 is a plan view of a SIMM board, which is an embodiment of the present invention, viewed from above.

2 is a diagram showing one COB type semiconductor device mounted on the wiring substrate shown in FIG. 1 of the present embodiment and its peripheral wiring.

FIG. 3 is a diagram showing a COB semiconductor device and a wiring 3 around the COB semiconductor device before resin sealing according to the present embodiment.

FIG. 4 is a diagram for explaining an alternative repairing method for a defective COB type semiconductor device in the present embodiment.

FIG. 5 is a diagram for explaining a SIMM substrate in which a packaged semiconductor device is stacked and mounted on the COB type semiconductor device of this embodiment.

FIG. 6 is a diagram for explaining the signal wirings connected to the COB type semiconductor device and the packaged semiconductor device of the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... COB type semiconductor device, 1a ... Semiconductor chip, 2 ... Wiring board, 3 ... Wiring, 3a ... Electrode pad connected to a semiconductor chip, 4 ... Land (spare electrode pad), 7 ... Wiring cut place, 10 ... SIMM substrate, 20 ... Other semiconductor devices packaged, AV, signal lines.

Claims (4)

[Claims] 1. An electronic device comprising a wiring board on which one or a plurality of COB type semiconductor devices are mounted, wherein the wiring board is provided at a predetermined position on a wiring electrically connected to the COB type semiconductor device. An electronic device comprising a second semiconductor device mounting auxiliary electrode pad. 2. An electronic device comprising a wiring board in which a second semiconductor device is stacked and mounted on one or a plurality of COB type semiconductor devices, wherein the wiring board is electrically connected to the COB type semiconductor device. And a second wiring electrically connected to the second semiconductor device, and a spare electrode pad for mounting the second semiconductor device at a predetermined position on the second wiring. And electronic equipment. 3. The electronic device according to claim 2, wherein when both the semiconductor devices designed with the same circuit are mounted on the wiring board, the wiring board has two systems of the both semiconductor devices. 2. An electronic device, comprising: the control switching wiring, and a shared wiring that shares the first wiring and the second wiring excluding the control switching wiring. 4. A method for substituting a defective COB type semiconductor device mounted on the electronic device according to claim 1, wherein a defect occurs in the COB type semiconductor device mounted on the electronic device. The wiring between the electrode pad of the wiring board connected to the defective COB type semiconductor device and the spare electrode pad is cut off, and a second semiconductor device that operates normally is stacked and mounted on the defective semiconductor device. A method for substituting a defective COB type semiconductor device mounted on an electronic device, the device being connected to a spare electrode pad.