JP3194040B2 - IC module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC module in which a plurality of IC chips are mounted, and an IC for easily inspecting a connection state between electrodes of the IC chip and wiring of the module.
About the module.

[0002]

2. Description of the Related Art FIG. 4 is a circuit diagram showing wiring of a conventional IC module. That is, a plurality of IC chips ₁₁ ,
1 _2, 1 ₃ is mounted, the IC chip ₁ 1, 1 _2, 1 ₃
Are connected to the module external connection input terminal and the module external connection output terminal 2 by corresponding common bus lines. Wherein each IC chip 1 _1, 1 _2, 1 ₃ of the power supply electrodes are wired to the module external connection power supply terminal 3 by a common bus line. Each IC
The ground electrode of the chip 1 _1, 1 _2, 1 ₃ are wired to the module an external ground connection terminal 4 by a common bus line. Wherein each IC chip 1 _1, 1 _2, 1 ₃ of the chip select electrodes each of which is wired to the module external connection chip select terminal 5 separately.

[0003] In such an IC module, testing the IC chip ₁ 1, 1 and _2, 1 ₃ each electrode of the connection between the wiring and the function of each IC chip ₁ 1, 1 _2, 1 ₃ However, in the conventional IC module, each IC
Chip 1 _1, 1 _2, 1 ₃ of the input electrode, the output electrode, the power supply electrode, since the ground electrode is connected to the terminals 2, 3 and 4 via a common bus line, respectively, the connection test and function test It could not be done separately. Therefore, by performing a function test, the connection state is also checked at the same time.

The function test is performed by connecting a power supply and a ground potential corresponding to the power supply terminal 3 and the ground terminal 4, respectively, and sequentially applying a selection signal to the chip select terminal 5 under environmental conditions such as high temperature. IC chips 1 ₁ , 1 ₂ ,
1 ₃ sequentially selects, in this each selected state, by examining the output signal from the output terminal 2 together with the addition of the input signal from the input terminal 2 for several 10 hours, the IC chip 1 _1, 1 _2, 1 ₃ Check functionality.

[0005]

[SUMMARY OF THE INVENTION However, the failure to results generated in the function test case of connection failure between the wiring of the chip 1 _1, 1 _2, 1 ₃ each electrode and modules was very large. When a defect occurs, a defective chip must be replaced and a function test requiring several tens of hours must be performed again. When a defect occurs, the function test is repeated, and a long time is required for the test as a whole. There were drawbacks.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables a connection test for detecting a connection failure that frequently occurs in a short time before a function test. An object of the present invention is to provide an IC module capable of reducing the number of times and performing an overall inspection in a short time.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a plurality of IC chips provided with a protection diode between input and output electrodes, a power supply electrode and a ground electrode. In the IC module in which the input electrode and the output electrode are wired to the input terminal for module external connection and the output terminal for module external connection by a common bus line, respectively, the power supply electrode or the ground electrode of each IC chip corresponds to the module external connection. The power supply terminal for connection or the ground terminal for external connection of the module is individually wired.

[0008]

The present invention relates to a power supply terminal for module external connection or a power supply terminal for a module external connection in which a plurality of input and output electrodes are mounted, and a power supply electrode or a ground electrode of an IC chip provided with a protection diode between a power supply electrode and a ground electrode. By separately wiring to the module external connection ground terminal, a connection test that detects frequently occurring connection failures in a short time can be performed separately before a function test, reducing the number of time-consuming function tests. Thus, the inspection can be performed as a whole in a short time.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing wiring of an IC module according to one embodiment of the present invention. That is, a plurality of I
The C chips 11 ₁ , 11 ₂ , and 11 ₃ are mounted, and the input electrodes and output electrodes of each of the IC chips 11 ₁ , 11 ₂ , and 11 ₃ are common bus lines, and are input terminals for module external connection and output terminals for module external connection. 12 is wired. The power supply electrodes of the IC chips 11 ₁ , 11 ₂ , 11 ₃ are individually connected to the power supply terminals 13 ₁ , 13
Wired to _2, 13 _3. Each of the IC chips 11 ₁ , 1
1 _2, 11 ₃ of the ground electrode is wired to the module an external ground connection terminal 14 by a common bus line. The chip select electrodes of the IC chips 11 ₁ , 11 ₂ and 11 ₃ are individually wired to the module external connection chip select terminal 15.

As shown in FIG. 2, the input terminal for module external connection and the output terminal 12 for module external connection, and the chip select terminal 15 for module external connection
Inside the C chips 11 ₁ , 11 ₂ , 11 ₃ , the power supply terminals 13 ₁ , 13 ₂ , 13 ₃ for module external connection and the ground terminal 14 for module external connection are connected via diodes D 1, D 2. . Each IC chip 1
1 _1, 11 _2, 11 ₃ internal diodes D1, circuit composed of D2 is commonly used as an input protection circuit in a conventional CMOS IC or the like, consisting of diodes D1, D2 also output circuit equivalent circuit It is used. The connection test in this IC module is performed by the following method prior to the function test.

Namely, the input and output electrodes, the power supply electrodes of the IC chip 11 _1, to confirm the connection of the ground electrode, the chip select electrode, the IC chip 11 _first module for external connection power supply terminal 13 ₁ only ground And a power supply voltage, for example, V _CC = 5V, to power supply terminals 13 ₂ , 13 ₃ for module external connection of the other IC chips 11 ₂ , 11 _3.
Is applied.

Next, a voltage of, for example, about 100 mV is sequentially applied to each module external connection input terminal and module external connection output terminal 12, module external connection ground terminal 14, and module external connection chip select terminal 15. The current is measured at each of the input and output terminals 12, the ground terminal 14, and the chip select terminal 15.
Here, if the specified current in the forward characteristics of the diode D1 is measured at the input and output terminals 12 and the chip select terminal 15, and the specified current in the forward characteristics of the diodes D1 and D2 is measured at the ground terminal 14, the IC chip 11 ₁
Input electrode and output electrode, power supply electrode, ground electrode, chip select electrode can be confirmed that each is correctly connected, and if there is a place where the specified current is not measured,
It can be confirmed that the connection between the corresponding electrode and the corresponding wiring is defective. Further, an input terminal and an output terminal 12, a ground terminal 14, a chip select terminal 15
Provisions to be determined that the current flows in the connection of the power supply electrodes of the IC chip 11 ₁ and its corresponding wiring it can be confirmed that has become defective. In this case, the input and output terminals 12, the ground terminal 14, and the chip select terminal 15 may be measured by inserting a resistance as necessary. Similarly, the other IC chips 11 ₂ , 1
Also with respect to one _third connection test can be carried out by the same procedure as the connection test IC chip 11 _1.

Such a connection test is performed on each IC chip 11
The connection state of each of the electrodes ₁ , _{1 1 2} and _{1 1 3} with each wiring can be electrically confirmed within a short period of time. If there is a connection failure at this time, I
The C chip is removed from the IC module, another IC chip is connected (repair), the connection state is checked again, and the next function test is performed in a state where all the IC chips have no connection failure.

The function test is performed under environmental conditions such as high temperature.
By connecting a power supply and a ground potential to the power terminals 13 ₁ , 13 ₂ , and 13 ₃ and the ground terminal 14 and applying a selection signal to the chip select terminal 15 sequentially, each IC chip 11 ₁ , 11 ₂ , 11 ₃ is connected. The function of each IC chip 11 ₁ , 11 ₂ , 11 ₃ is inspected by sequentially selecting and in each selected state applying an input signal from the input terminal 12 for several tens of hours and checking an output signal from the output terminal 12. I do.

As described above, although the function test requires a long time, the function test is performed in a state where connection failures, which are far more than the function failures of the IC chip, are removed in a short time by the connection test in advance. Inspection can be performed in a short time.

The IC chip includes a mask ROM,
There is a memory chip such as an EPROM, an EEPROM, an ASIC, or a driver chip for driving an LCD or the like.

FIG. 3 is a circuit diagram showing wiring of an IC module according to another embodiment of the present invention. That is, a plurality of IC chips 11 ₁ , 11 ₂ , 11 ₃ are mounted, and each IC chip
The input and output electrodes of the chips 11 ₁ , 11 ₂ and 11 ₃ are wired to the input terminal for module external connection and the output terminal 12 for module external connection by a common bus line. The power supply electrodes of the IC chips 11 ₁ , 11 ₂ , and 11 ₃ are wired to the module external connection power supply terminal 13 by a common bus line. The ground electrodes of the IC chips 11 ₁ , 11 ₂ , _{11 3} are individually wired to the module external connection ground terminals 14 ₁ , 14 ₂ , 14 ₃ . The chip select electrodes of the IC chips 11 ₁ , 11 ₂ , and 11 ₃ are individually provided as chip select terminals 1 for module external connection.
5 is wired. The connection test in this IC module is performed by the following method prior to the function test.

[0019] That is, IC chip 11 of the _input electrodes and output electrodes, the power supply electrodes in order to check the connection of the ground electrode, the chip select electrodes, IC chip 11 _first module 100mV only external connection ground terminal 14 ₁ the degree of voltage is applied, the other IC chip 11 _2, 11 ₃ of the module external connection ground terminal 14 _2, 14 ₃ is grounded.

Next, the module external connection input terminal and module external connection output terminal 12, the module external connection power supply terminal 13, and the module external connection chip select terminal 15 are sequentially grounded. The current is measured at the output terminal 12, the power supply terminal 13, and the chip select terminal 15. Here, if the specified current in the forward characteristics of the diode D2 is measured at the input and output terminals 12 and the chip select terminal 15, and the specified current in the forward characteristics of the diodes D1 and D2 is measured at the power supply terminal 13, the IC chip 11 of the _input electrodes and output electrodes, the power supply electrodes, a ground electrode, it is confirmed that the chip select electrode is properly connected, and, if you have locations specified current is not measured, the electrode and its corresponding corresponding thereto It can be confirmed that the connection with the formed wiring is defective. Furthermore, an input terminal and an output terminal 12, a power supply terminal 1
3, to be measured may flow current provision to the chip select terminal 15, connection of the IC chip 11 ₁ of the ground electrode and its corresponding wiring it can be confirmed that has become defective. In this case, each input terminal and output terminal 1
2, the power supply terminal 13, the chip select terminal 15,
If necessary, a resistor may be inserted and measurement may be performed with an ammeter.
Similarly, the connection inspection of the other IC chips 11 ₂ and 11 ₃ can be performed in the same procedure as the connection inspection of the IC chip 11 ₁ .

[0021]

As described above, according to the present invention, a power supply electrode or a ground electrode of an IC chip provided with a protective diode between a plurality of mounted input and output electrodes and a power supply electrode and a ground electrode is respectively provided. By individually wiring to the corresponding power supply terminal for module external connection or the ground terminal for module external connection, it is possible to perform a connection test to detect frequently occurring connection failures in a short time prior to the function test. By reducing the number of time-consuming functional tests, the tests can be performed in a short time as a whole.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing an example of the inside of an IC chip according to the present invention.

FIG. 3 is a circuit diagram showing another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a conventional IC module.

[Explanation of symbols]

11 ₁ , 11 ₂ , 11 ₃ ... IC chip, 12 ... Module external connection input terminal and module external connection output terminal, 13, 13 ₁ , 13 ₂ , 13 ₃ ... Module external connection power supply terminal, 14, 14 ₁ , 14 ₂ , 14 ₃ ... Ground terminal for module external connection, 15... Chip select terminal for module external connection.

Claims (1)

(57) [Claims] A plurality of IC chips each having a protection diode provided between an input electrode and an output electrode and a power supply electrode and a ground electrode are mounted, and the input electrode and the output electrode of each IC chip are externally connected to a common bus line. IC wired to input terminal for connection and output terminal for module external connection
In the module, the power supply electrode or the ground electrode of each IC chip is individually wired to a corresponding module external connection power supply terminal or module external connection ground terminal.