JP2002299460A - Semiconductor integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit capable of executing an adjacent leakage measurement before cutting a fuse and reduce the number of probes necessary to measure the outputs as compared with the number of output pins. SOLUTION: The semiconductor integrated circuit comprises a plurality of groups of output terminals PN, PN+1 , etc., for electrically connecting to an external unit, a plurality of groups of output circuits QN, QN+1 , etc., corresponding to these output terminals, a control circuit 10 for controlling the plurality of the output circuits so as to output the output signal by the sequentially selected one output circuit in the output circuits of the respective groups and to set the output to a high impedance by another output circuit, and a plurality of fuses 1, 2, etc., each connected between a predetermined output terminal of the one group and a predetermined output terminal of another group and thereafter melted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a semiconductor integrated circuit, and more particularly to a semiconductor integrated circuit having a large number of output terminals, such as a liquid crystal driver IC, which is inspected by using an inspection device (such as an LSI tester). The present invention relates to a semiconductor integrated circuit that facilitates connection with a device.

[0002]

2. Description of the Related Art Conventionally, when testing a semiconductor integrated circuit having a large number of output terminals (pins and pads), such as a liquid crystal driver IC, the terminals of the semiconductor integrated circuit must be tested in order to test all the output terminals. The same number of probes are set on the probe card, and the inspection is performed using a high-performance LSI tester capable of handling a large number of pins.

For example, when a semiconductor integrated circuit has 300 terminals, 300 probes connected to an LSI tester are erected on a probe card to connect to the terminals of the semiconductor integrated circuit. . However, the distance between terminals in a semiconductor integrated circuit is becoming smaller year by year, and it is becoming difficult to physically set probes on all terminals. In addition, a probe card having a large number of probes and a high-performance LSI tester capable of handling a large number of pins are expensive, and therefore the inspection cost is also high.

In order to improve this, as shown in FIG.
Semiconductor integrated circuits are conceivable. This semiconductor integrated circuit
The output buffer circuit B_N, B_{N + 1}...
The force is the switching transistor Q_N, Q_{N + 1},
Via the output pin P _N, P_{N + 1}, Contact
Has been continued. Also, the transistor Q_N, Q_{N + 1},
..Gate of each transistor to control operation of
Is provided with a control circuit 110 for supplying a control signal to the
You. Further, two adjacent output pins P_NAnd P_{N +1}When
The fuse 101 is connected between the two
Force pin P_{N + 2}And P_{N + 3}Fuse 102 is between
It is connected.

In an operation test of a semiconductor integrated circuit,
For example, two adjacent output pins P _NAnd P_{N + 1}With
(In FIG. 4, the output pin P_N) To probe 12
Set 1 to output pin P_NAnd P_{N + 1}And supply the output to
Transistor Q_NAnd Q_{N + 1}Turn on one of
Output buffer circuit by turning off the other
Road B_NOutput and output buffer circuit B_{N + 1}With the output of
Measure with each other. When the operation test is completed, fuse 10
.., Laser light irradiation and high voltage application
And cut. This allows the output of the semiconductor integrated circuit to be
The number of probes required for measurement is determined by the output
Can be reduced by half.

[0006]

However, according to such a semiconductor integrated circuit, when two adjacent output pins are connected by a fuse, the leak between the adjacent pins cannot be measured. Therefore, it is necessary to perform a leak test between adjacent pins after cutting the fuse, which causes a problem that the test process becomes complicated.

In view of the above, the present invention provides a semiconductor integrated circuit that can reduce the number of probes required for output measurement from the number of output pins and can also perform adjacent leak measurement before cutting a fuse. It is intended to provide a circuit.

[0008]

In order to solve the above-mentioned problems, a semiconductor integrated circuit according to the present invention has a plurality of groups of output terminals for electrically connecting to the outside and a plurality of groups of output terminals. A plurality of output circuits, each of which outputs an output signal having one of three or more possible values, or sets the output to a high impedance state. A group of output circuits and, in an output test, a plurality of groups of output circuits sequentially selected so that one of the output circuits in each group outputs an output signal and the other output circuit sets the output to a high impedance state. A control circuit for controlling an output circuit; and a plurality of fuses, each of which is connected between a predetermined output terminal of one group and a predetermined output terminal of another group in at least an output test and an adjacent leak test. Is Comprising a plurality of fuses to be subsequently cut.

In the output test, the control circuit outputs one of the plurality of output circuits corresponding to the plurality of output terminals connected by the fuse, and outputs the output signal to the other output circuit. A plurality of groups of output circuits are controlled so as to be in a high impedance state.

In the adjacent leak test, a plurality of groups of output circuits output output signals having different values to adjacent output terminals and output signals having the same value to a plurality of output terminals connected by fuses. Output.

According to the semiconductor device of the present invention configured as described above, in the output test, the control circuit sequentially selects one of the output circuits of each group and outputs its output signal to one of the groups. Since the output is output to the output terminal and the output of the other output circuit is set to the high impedance state, only one probe of the inspection jig needs to be set up for each group of output terminals. In the adjacent leak test, a plurality of groups of output circuits output output signals having different values to adjacent output terminals, and output output signals having the same value to a plurality of output terminals connected by fuses. By doing so,
An adjacent leak test can be performed before cutting the fuse.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same components are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a diagram showing a part of the configuration of the semiconductor integrated circuit according to the first embodiment of the present invention.

In FIG. 1, this semiconductor integrated circuit is
Groups of output pins P for making electrical connection with the unit_N,
P_{N + 1},···have. In this embodiment
, Two output pins constitute one group. these
Multiple groups of outputs to provide output signals to the output pins of
Buffer circuit B_N, B_{N + 1}, ... are plural groups of sui
Transistor Q for switching_N, Q_{N + 1}Through ...
And a plurality of output pins P _N, P_{N + 1}...
Connected. Here, each output buffer circuit and
Combination with the corresponding switching transistor,
One output circuit is configured. Note that each output circuit
Switching between the output signal and the input signal
Each output pin can be used as an I / O pin.
Absent.

Each output buffer circuit has three or more values.
Possible value (in the present embodiment, V_A, V_B, V_C)
An output signal having one of the following values is output. Also, each
The gate voltage of each switching transistor is high.
When the gate voltage is low,
It turns off when the bell is on. Transistor Q_N, Q
_{N + 1}, ... to control the operation of these
The control circuit 10 that supplies a control signal to the gate of the transistor
Is provided. In addition, a non-adjacent output pin P_N
And P_{N + 3}Between output pins P_{N + 1}When
P_{N + 4}Between, ..., fuses 1, 2, ...
Are connected respectively.

In a test of a semiconductor integrated circuit, each group
Output pin (in FIG. 1, the output pin
Force pin P_N, P_{N + 2}, P_{N + 4}) To probe 21, 2
Stand 2 and 23 respectively. Next, for example, fuse 1
Output pin P connected by _NAnd P_{N + 3}And output to
Supply transistor Q_NAnd Q_{N + 3}Turn on one of
By turning off the other, the output buffer circuit B
_NOutput and output buffer circuit B_{N + 3}Alternate with the output of
Measure. Thereby, using one probe 21,
The output pin P on which the probe 21 is standing_NOutput signal
Not only the output pin P with no probe
_{N + 3}Can be measured. This
The number of probes required to measure the output of the semiconductor integrated circuit
Can be reduced to half the number of output pins of the semiconductor integrated circuit.
Wear.

Further, according to the present invention, since adjacent output pins are not connected by a fuse, a leak (short) between adjacent output pins can be obtained without cutting the fuse.
It is possible to perform an adjacent leak test that measures
In other words, different voltage _V A between adjacent output _{pins, V} C, V
_{If B} , V _A ,... Are output, a large current flows when the adjacent output pins are short-circuited. Can be detected.

When the operation test and the adjacent leak test are completed, the fuses 1, 2,... Are cut by irradiating a laser beam or applying a high voltage.

FIG. 2 shows another example of an output circuit that can be used in this embodiment. In FIG. 2, only the first group of output circuits is shown, and the fuse is omitted. FIG.
As shown, the output pins P _N, transistor Q
A _N , QB _N , and QC _N are connected in parallel. Similarly, the output pin P _{N + 1} is connected to the transistor QA _{N + 1} ,
QB _{N + 1} and QC _{N + 1} are connected in parallel.

The power pins _{P A,} P B, the _{P C,} via the ammeter 41, 42 and 43, respectively, different power supply voltages _{V A, V B, V C} is connected. Transistor QA
_N is a transistor for supplying a power supply voltage _{V A} at the output pins _{P N,} transistor QB _N is output pin P
A transistor for supplying a power supply voltage _{V B} to _N, the transistor QC _N, the power supply voltage V to output pins _{P N}
It is a transistor for supplying _C.

The transistors _{QA N,} QB N, the gate of the QC _N is connected to the control circuit 30. Control circuit 30
Turns on one of these transistors to output an output signal having one of three or more possible values from an output circuit. Alternatively, the control circuit 30 turns the output of the output circuit into a high impedance state by turning off all of these transistors.

In the adjacent leak test, for example, FIG.
As shown in, and supplies the output pins _{P N} to the power supply voltage _{V A} transistor QA _N is turned on to supply the power supply voltage _{V C} to the output pin _{P N + 1} the _{QC N + 1} as an on-state. If the output pins P _N and P _{N +1} are short-circuited, since a large current is observed in the ammeters 41 and 43, such a short-circuit can be detected.

Next, a second embodiment of the present invention will be described.
I will tell. FIG. 3 shows a semiconductor according to a second embodiment of the present invention.
FIG. 2 is a diagram illustrating a part of a configuration of an integrated circuit. In this embodiment,
In addition, three output pins constitute one group. Ma
A non-adjacent output pin P_NAnd P_{N + 5}Between
The output pin P to which the fuse 61 is connected and is not adjacent
_{N + 5}And P_{N + 7}Fuse 62 is connected between
I have. Similarly, output pin P_{N + 1}And P_{N + 3}Between
Fuse 63 is connected and output pin P_{N + 3}And P _{N + 8}
And a fuse 64 is connected between them.

In the test of the semiconductor integrated circuit, one of the output pins of each group (in FIG. 1, output pins P _N , P _{N + 3} , P _{N + 6} ) is connected to probes 81 and 8.
Stand 2 and 83 respectively. Next, for example, fuse 6
The output pins P _N , P _{N + 5} , connected at 1 and 62,
A transistor Q _N that provides an output to P _{N + 7} ,
By turning on one of Q _{N + 5} and Q _{N + 7} and turning off the other, output buffer circuits B _N , B _{N + 5} , B _N
The output of _{N + 7} is measured alternately. Thus, using a single probe 81, not only the output signal of the output pins P _N where the probe 81 is erected, measuring the output signal of the output pins P _{N + 3} and output pins P _{N + 7} probe is not set can do. Thus, the number of probes required for measuring the output of the semiconductor integrated circuit can be reduced to １ ／ of the number of output pins of the semiconductor integrated circuit.

Further, according to the present invention, since adjacent output pins are not connected by a fuse, leakage (short circuit) between adjacent output pins can be achieved without cutting the fuse.
It is possible to perform an adjacent leak test that measures
That is, if different voltages are output between adjacent output pins, a large current flows when the adjacent output pins are short-circuited. Therefore, the output current is measured by measuring the current consumption of the semiconductor integrated circuit. A short circuit between pins can be detected.

When the operation test and the adjacent leak test are completed, the fuses 61, 62,... Are cut by irradiating a laser beam or applying a high voltage.

[0026]

As described above, according to the present invention, in the output test, the control circuit sequentially selects one of the output circuits of each group and outputs the output signal to one output terminal of each group. And the outputs of the other output circuits are brought into a high impedance state, so that only one probe of the inspection jig needs to be set up for each group of output terminals. In the adjacent leak test, a plurality of groups of output circuits output output signals having different values to adjacent output terminals, and output output signals having the same value to a plurality of output terminals connected by fuses. By doing so, an adjacent leak test can be performed before the fuse is cut.

Therefore, a multi-pin output device can be measured with a small-pin tester, and adjacent leaks can be measured with a fuse. This simplifies the test process of the semiconductor integrated circuit. Further, it becomes possible to measure a narrow pitch device using a conventional probe card.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a part of a configuration of a semiconductor integrated circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating another example of an output circuit that can be used in the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a part of a configuration of a semiconductor integrated circuit according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an improvement plan of a conventional semiconductor integrated circuit.

[Explanation of symbols]

1,2, fuse 10,30,70 controller 21～23,81～83 probes 41-43 ammeter _{B N, B N + 1,} ··· output buffer circuit _{Q N, Q N + 1,} ···, QA _N , QB _N , QC _N Transistors P _N , P _{N + 1} ,... Output pins

Continuation of the front page F term (reference) 2G132 AA01 AB01 AD01 AD15 AK00 AK07 AL05 2H088 FA11 HA08 MA20 5F038 AV15 CA10 DT15 EZ20 5F064 BB31 BB33 DD46 FF12 FF27 FF42 FF46

Claims (3)

[Claims] 1. A plurality of groups of output terminals for electrically connecting to the outside, and a plurality of groups of output circuits corresponding to the plurality of groups of output terminals, wherein each of the output circuits has three or more values. Outputting the output signal having one of the possible values or bringing the output into a high impedance state; and sequentially selecting one of the output circuits of each group in an output test. A control circuit for controlling the plurality of output circuits so that one of the output circuits outputs an output signal and the other output circuit sets the output to a high-impedance state; and And a plurality of the fuses, each fuse being connected between a predetermined output terminal of one group and a predetermined output terminal of another group in an adjacent leak test, and thereafter cut off. Product circuit. 2. The control circuit according to claim 1, wherein:
The plurality of groups are arranged such that one output circuit of a plurality of output circuits corresponding to a plurality of output terminals connected by the fuse outputs an output signal, and the other output circuit sets an output to a high impedance state. 2. The semiconductor integrated circuit according to claim 1, wherein the output circuit is controlled. 3. The plurality of groups of output circuits, in an adjacent leak test, output output signals having different values to adjacent output terminals, and the same value is output to a plurality of output terminals connected by the fuse. The semiconductor integrated circuit according to claim 1, wherein the semiconductor integrated circuit outputs an output signal.