JP4116693B2 - Low power semiconductor integrated circuit for leak current and leak inspection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor integrated circuit, and more particularly to a leakage current compatible low power semiconductor integrated circuit equipped with MOS transistors having different threshold values for low power consumption and a method for inspecting the same.
[0002]
[Prior art]
In recent years, there has been a strong demand for lower power (power consumption) of semiconductor integrated circuits in order to reduce the size and increase the integration of semiconductor devices. In order to reduce the power consumption, it is effective to reduce the power supply voltage. (Note, power consumption is CV ² Determined by f. Here, C is an internal capacitance, V is a power supply voltage, and f is an operating frequency. However, simply lowering the power supply voltage slows down the transistor operating speed (on / off switching speed). For this reason, the threshold voltage of MOS transistors (field effect transistors that control current paths by applying a voltage to a gate electrode that is electrically insulated from the current paths by an oxide film) is being reduced.
[0003]
By the way, in the CMOS circuit composed of this low threshold transistor, the leakage current (Idddq) in the steady state increases when the potential of the input terminal of each node does not change. (For these items, the reasons for this, and other driving voltages, for example, IEICE Technical Report 1CD93-107 (1993-10) Yasuyuki Matsutani et al. “IV, 10MH” _Z Since it is a well-known matter described in “Operation Multi-Threshold CMOS Logic Circuit Technology” and the like, further explanation is omitted. )
Apart from this, as the scale of the semiconductor integrated circuit becomes larger, the leakage current of the entire circuit becomes larger and larger.
[0004]
For this reason, since the leakage current caused by the failure is relatively smaller than the leakage current in the steady state, it is difficult to detect the failure by detecting an increase in the leakage current of the entire circuit. ing.
Therefore, as measures against this, for example, the following means has been proposed in IEEE 1996 CUSTOM INTEGRATED CIRCUIT CONFERENCE.
[0005]
FIG. 9 is an electric circuit diagram showing a part of the schematic configuration of the proposed semiconductor integrated circuit (only the part related to the present invention).
As shown in this figure, the semiconductor integrated circuit is divided into a plurality of functional blocks (here, two functional blocks 9041 and 9042 are illustrated as logic circuits).
[0006]
Between the normal power supply terminal 901, which is a power supply terminal used during normal operation of this functional block, and the pseudo power supply lines 9071, 9072 that directly supply voltage to the functional blocks 9041, 9042, there is no power supply. MOS transistors 9051 and 9052 for controlling supply are interposed. (Note that the electric wires paired with the normal power supply terminal 901, for example, the diodes provided on the ground signal line and the pseudo power supply line are not shown because they are complicated. In addition, between the two functional blocks 9041 and 9042) Since the role of the signal is a well-known fact, its explanation is omitted.)
[0007]
Further, MOS transistors 9061 and 9062 for controlling the supply of power are also interposed between the inspection power supply terminal 902 which is a power supply terminal used for inspection and the pseudo power supply lines 9071 and 9072.
Next, in response to the control signal 900, the control circuit 903 controls the MOS transistors 9061 and 9062 such that power is supplied from the inspection power supply terminal 902 to only one of the two functional blocks 9041 and 9042. At the same time, the MOS transistors 9051 and 9052 are also controlled so that power is supplied from the normal power supply terminal 901 only to the other functional block.
[0008]
Hereinafter, it is assumed that there is a failure with a large leakage current in the functional block 9041, and the procedure (operation) for finding the failure or determining the presence / absence thereof will be described. When the inspection of the functional block 9041 is designated by the control signal 900, the control circuit 903 serving as means for designating the inspection object turns off the MOS transistor 9051 (OFF, closes), turns on the same 9052 (ON, open), and Control is performed so that 9061 is turned on and 9062 is turned off.
[0009]
As a result, only the inspection power supply terminal 902 supplies power to the functional block 9041, and the normal power supply terminal 901 supplies power to the other functional block 9042. For this reason, it is possible to measure only the leak current flowing in the steady state of the functional block 9041 by measuring the amount of current at the inspection power supply terminal 902.
[0010]
Since the difference between the leakage current including the increase due to the failure in the functional block 9041 and the leakage current when there is no failure in the functional block 9041 is of course larger than the difference between the leakage current of the entire semiconductor integrated circuit. By measuring the current of the inspection power supply terminal 902, it becomes easy to determine whether or not there is a failure.
The above is the case where there are two functional blocks. However, even in the case where there are three or more functional blocks, it goes without saying that the MOS transistor intervening structure and the ON / OFF control are similarly performed. .
[0011]
Next, in a C (Complementary) MOS semiconductor integrated circuit composed of low threshold transistors, the steady-state leakage current inevitably increases, so that the power consumption of a device using this semiconductor integrated circuit increases unnecessarily. Tend to. Therefore, as one of the CMOS semiconductor integrated circuits considering this countermeasure, an MT-CMOS (Multi-Threshold CMOS) semiconductor integrated circuit in which a low threshold transistor and a high threshold transistor are arranged is proposed. Has been.
[0012]
As an example of this conventionally proposed MT-CMOS semiconductor integrated circuit, for example, there is the one shown in the Institute of Electronics, Information and Communication Engineers: IEICE Technical Report ICD93-107 (19933-10). Hereinafter, the MT-CMOS semiconductor integrated circuit will be described with reference to FIG.
[0013]
FIG. 8 is an electric circuit diagram showing a part of the schematic configuration of the MT-CMOS semiconductor integrated circuit. As shown in this figure, a pseudo power supply line 805 is configured by a low threshold transistor between a power supply terminal 801 that supplies a high potential side voltage for operation and a power supply terminal 802 that provides a low potential side voltage. And a functional block (illustrated as a logic circuit) 807 that uses the pseudo power supply line 806 as a power source on the high potential side and the low potential side, respectively. High threshold transistors 803 and 804 are interposed between the power supply terminal 801 and the pseudo power supply line 805 and between the power supply terminal 802 and the pseudo power supply line 806, respectively.
[0014]
The operation of the circuit shown in FIG.
When the function block 807 operates, charges are supplied to the function block 807 by turning on the high threshold transistors 803 and 804, and the function block 807 including the low threshold transistors operates at high speed. On the other hand, during standby, the high threshold transistors 803 and 804 are turned off, so that leakage current from the power supply terminal 801 to the functional block 807 and from the functional block 807 to the power supply terminal 802 is suppressed. Accordingly, the leakage from the power supply terminal 801 to the power supply terminal 802 can be suppressed very small.
[0015]
[Problems to be solved by the invention]
However, in the first conventional low-power semiconductor integrated circuit corresponding to the leakage current, two transistors and two control signal lines are required for each divided functional block. Therefore, a necessary area on the integrated circuit is required. Will lead to an increase in manufacturing costs.
For this reason, it is desired to develop and implement a semiconductor integrated circuit and its inspection method with reduced manufacturing cost by enabling the inspection power supply terminal to control the functional block that supplies voltage with a smaller circuit configuration. It was.
[0016]
Next, in the second conventional low-current semiconductor integrated circuit corresponding to leakage current, the pseudo power supply line 805 is always due to a short circuit between the source and drain of the high threshold transistors 803 and 804, failure of the control line, and the like. , 806 when a failure (hereinafter referred to as an on-failure) in which voltage is supplied from the power supply terminals 801 and 802, or disconnection of a connection line to the power supply terminals of the high threshold transistors 803 and 804, Due to disconnection of the connection line to the power supply line, failure of the control signal line, etc., a failure (hereinafter referred to as “off failure”) in which voltage cannot be supplied from the power supply terminals 801 and 802 to the pseudo power supply lines 803 and 804 occurred. In some cases, the following problems may occur.
[0017]
First, in the case where an on-failure occurs, when the function block 807 is operated, the high threshold transistors 803 and 804 are controlled to be on and voltages are supplied from the respective power supply terminals 801 and 802. It operates normally and does not adversely affect the operation. On the other hand, when the function block 807 is in a standby state (power is supplied but the circuit is stopped), the high threshold transistors 803 and 804 are controlled to be turned off. Have been supplied. At this time, since this is a standby time, this itself has no logical adverse effect.
[0018]
However, since the high threshold transistors 803 and 804 are not turned off during standby, a large leakage current from the power supply terminal 801 to the power supply terminal 802 is generated via the function block 807 configured by the low threshold transistors. It will be. As a result, the advantage of the MT-CMOS semiconductor integrated circuit that the leakage current during standby is small is lost.
[0019]
However, in the conventional MT-CMOS semiconductor integrated circuit, such a failure that the high threshold transistors 803 and 804 are not turned off cannot be detected.
[0020]
In addition, when an off-failure occurs, the voltage is not supplied, so that the function block 807 naturally does not operate. However, when a situation that does not operate once occurs, the cause is the high threshold transistors 803 and 804. It is difficult to immediately distinguish and detect whether it is in the power supply part such as the function block 807 or the like. Therefore, it was often difficult to reduce the frequency of subsequent failures by improving the design.
[0021]
For this reason, there is provided means for detecting an on-failure, realizing an inspection method for an MT-CMOS semiconductor integrated circuit capable of reliably exhibiting a function capable of high-speed operation and low power consumption, and means for detecting an off-fault. Of a low-power semiconductor integrated circuit and a method for inspecting the same, rather than an MT-CMOS capable of distinguishing and detecting whether the function block does not operate in the power supply portion or the function block. Realization was desired.
[0022]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and by providing a power supply terminal for inspection on a pseudo power supply line and using a diode, it is easy to find a fault in which a leak current occurs and to specify a fault location. It is an object of the present invention to provide a low-power semiconductor integrated circuit capable of leak current and an inspection method therefor. Specifically, the configuration is as follows.
[0023]
In the first aspect of the invention, the first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, the first terminal, and the second terminal A functional block which is driven by electric power (one is at a high potential and the other is at a low potential) and further includes a plurality of low threshold transistors (including other elements incorporated); Between the terminal and the functional block (including a mode in which wiring is interposed between the terminals if electrically connected), and switching between on and off according to an external switching signal. A high-threshold transistor that switches the connection state between the first terminal and the functional block between ON and OFF, and a second terminal that is interposed between the second block and the functional block. Connection status with function block At least one of the high threshold transistors to be switched on and off, and a first terminal corresponding to the high threshold transistor when a high threshold transistor is interposed Alternatively, when a second terminal is connected and no high threshold transistor is interposed, a total of two power lines connecting (directly) the first terminal or the second terminal and the functional block And at least one pseudo power supply line (two if there are two high threshold transistors) and at least one pseudo power supply line connecting the high threshold transistor and the functional block (directly). (2 if there are two high threshold transistors) inspection terminals, and control means for controlling on / off switching of the high threshold transistors by an instruction from an inspector, an inspection signal from a tester, etc. In the leak current corresponding type low power semiconductor integrated circuit including,
[0024]
An on control step of turning on the high threshold transistor by control means provided for inspection of the high threshold transistor, and a high threshold transistor controlled to be on after the on control step. An inspection step for inspecting resistance between the connected first terminal or second terminal and the corresponding inspection terminal, and a resistance value in the inspection step is equal to or greater than a predetermined value. In some cases, the high-threshold transistor that is controlled to be on in the above-described leak-compatible low-power semiconductor integrated circuit is defective, and in many cases, the leak-compatible low-power semiconductor integrated circuit integrated with the high-threshold transistor This is a method for inspecting a leakage-compatible low-power semiconductor integrated circuit having a transistor determination step for determining whether the transistor is defective.
[0025]
With the above configuration, the first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, and the first terminal and the second terminal are used to drive the power. In addition to this, a functional block configured by further arranging a plurality of low threshold transistors, and a switch between the first terminal and the functional block, are switched from the outside. High threshold transistor for switching on and off the connection state between the first terminal and the functional block by switching between on and off according to the signal, and a leak prevention high threshold transistor and the second terminal and the functional block At least one of the high threshold transistors switching the connection state between the second terminal and the functional block between on and off by switching between on and off. When a high threshold transistor is interposed, the high threshold transistor is connected to the corresponding first terminal or second terminal, and the high threshold transistor is interposed. If not, a total of two power lines connecting the first block or the second terminal and the functional block, and at least one connecting the high threshold transistor and the functional block (high threshold transistor) 2 if there are 2) pseudo power supply line, at least one test terminal connected to the pseudo power supply line (2 if there are 2 high threshold transistors), In the leak current compatible low power semiconductor integrated circuit including the control means for controlling the switching of off, the following operation is performed.
[0026]
In the ON control step, control means provided separately or incorporated in the substrate or the like turns the high threshold transistor on (ON, energized state) by applying a voltage or the like.
In the inspection step, of course, if necessary, the other transistor is turned off (OFF, closed), or after applying a constant voltage to the first or second terminal and the inspection terminal, it is turned on by the on control step. The resistance between the corresponding first terminal or the second terminal connected to the high threshold transistor controlled to the same and the corresponding inspection terminal is measured.
[0027]
In the transistor determination step, when the resistance value measured in the inspection step is equal to or higher than a predetermined value determined in advance according to the measurement condition or the like, the leak-corresponding low power semiconductor integrated circuit is controlled to be turned on. The threshold transistor is determined to be defective due to an on-failure, and in many cases, the leak-compatible low power semiconductor integrated circuit integrated with the high threshold transistor is also determined to be defective. (Of course, if there are two high-threshold transistors, one of them may be measured immediately after it is determined to be on-failure, or the other transistor may be measured and discarded immediately.)
[0028]
In the invention according to claim 2, the first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, the first terminal and the second terminal A functional block that is driven by electric power and further includes a plurality of low threshold transistors, and is interposed between the first terminal and the functional block. The first terminal is switched on and off. Are connected between the functional block and the high-threshold transistor that switches the connection state between the first and second functional blocks between ON and OFF, and the second terminal and the functional block. If a high threshold transistor is interposed between at least one of the high threshold transistors that switch the connection state between ON and OFF, and this high threshold transistor When a corresponding first terminal or second terminal is connected and a high threshold transistor is not interposed, a total of two terminals connecting the first terminal or second terminal and the functional block are connected. A power line, at least one pseudo power line connecting the high threshold transistor and the functional block, at least one test terminal connected to the pseudo power line, and turning on the high threshold transistor. In a leakage current-compatible low power semiconductor integrated circuit comprising control means for controlling switching of off,
[0029]
An off control step of turning off at least one of the high threshold transistors by at least one of the high threshold transistors by the control means, and the off threshold after the off control step. A potential applying step for applying different potentials to the first terminal or the second terminal connected to the high threshold transistor and the corresponding inspection terminal, and a different potential applied after the potential applying step A leakage current measuring step for measuring a leakage current between the first terminal or the second terminal and the inspection terminal;
[0030]
A function block determination step for determining that the high-threshold transistor that is controlled to be off of the leakage-compatible low-power semiconductor integrated circuit is defective when the measurement value in the leakage current measurement step is equal to or greater than a predetermined value; This is a method for inspecting a leakage-compatible low-power semiconductor integrated circuit.
[0031]
With the above configuration, the first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, and the first terminal and the second terminal are used to drive the power. Further, a functional block configured by arranging a plurality of low threshold transistors, and is interposed between the first terminal and the functional block, and the first terminal and the functional block are switched on and off. A high-threshold transistor that switches the connection state between on and off and the second terminal and the functional block are interposed, and the connection state between the second terminal and the functional block is turned on by switching between on and off When the high threshold transistor is interposed between at least one of the high threshold transistors to be switched to and off, the high threshold transistor and the first terminal are provided. Is connected to the second terminal, and when a high threshold transistor is not interposed, a total of two power lines connecting the first terminal or the second terminal and the functional block, Controls on / off switching of at least one pseudo power supply line connecting the threshold transistor and the functional block, at least one test terminal connected to the pseudo power supply line, and the high threshold transistor. In the leakage current compatible low power semiconductor integrated circuit including the control means, the following operation is performed.
[0032]
In the off control step, the control means turns off the high threshold transistor, and if there are two high threshold transistors, at least one of them is turned off in accordance with the instruction from the inspector or the test signal from the tester. . (If both are tested at the same time, turn both off.)
In the potential application step, the first terminal or the second terminal connected to the high threshold transistor turned off after the off control step and the corresponding inspection terminal are often used for inspection. A different predetermined potential is applied.
[0033]
In the leakage current measurement step, between the first terminal or the second terminal to which a different potential is applied and the inspection terminal while the other post-energization transistor is turned off as necessary after the potential application step. Measure the leakage current.
In the function block determination step, if the measured value in the leakage current measurement step is equal to or greater than the predetermined value determined from the potential difference, etc., turn off the high-threshold transistor in the leak-compatible low-power semiconductor integrated circuit A failure is determined as a failure.
[0034]
According to a third aspect of the present invention, there is provided a functional block set comprising a functional block and a pseudo power supply line for supplying a high-potential side or a low-potential side power to the functional block, and an inspection target among the plurality of functional blocks. Inspection target designating means (including a signal line for transmitting a signal, etc.) for outputting a signal such as a voltage for designating a functional block, and a pseudo power supply for the functional block to be inspected designated by the inspection target designating means An inspection power supply terminal for supplying power to the line, a normal power supply terminal for supplying power to a pseudo power supply line of a functional block not designated as an inspection target by the inspection object designating means, the normal power supply terminal, and each of the pseudo power supplies Those connected to the pseudo power supply line of the functional block designated as the inspection object by the presence or absence of the designation signal from the inspection object designating means are controlled to be turned off. Those connected to the pseudo power supply lines of the functional blocks not designated as inspection targets are energization control transistors provided for each functional block set controlled to be on, the test power supply terminals, and each of the pseudo power supply lines In the meantime, a leakage-compatible low-power semiconductor integrated circuit having a diode provided for each functional block set and interposed in the direction in which power is supplied.
[0035]
With the above configuration, the following operations are performed.
It has a functional block set including a functional block and a pseudo power supply line for supplying power to the functional block on the high potential side or the low potential side.
The inspection target designating means outputs a signal for designating a functional block (group) to be inspected from a plurality of functional blocks (group) in accordance with an inspector's instruction, an inspection signal from a tester, or the like. Specifically, it controls on / off of a current control transistor (note, not necessarily a high threshold transistor) provided in each functional block set.
[0036]
The inspection power supply terminal supplies power to the pseudo power supply line of the functional block to be inspected designated by the inspection subject designating means. (Alternatively, it has such wiring and structure.)
The normal power supply terminal supplies power to the pseudo power supply line of the functional block that has not been specified as the inspection target by the inspection target specifying means. (Alternatively, it has such wiring and structure.)
[0037]
For example, a high-threshold transistor for energization control provided for each functional block set is provided between the normal power supply terminal and each of the pseudo power supply lines. Those connected to the pseudo power supply line of the functional block designated as the inspection target (for example, high or low voltage) are controlled off, and those connected to the pseudo power supply line of the functional block not designated as the inspection target Controlled on.
For each functional block set, a diode is interposed between the inspection power supply terminal and each pseudo power supply line in the direction in which power is supplied.
[0038]
According to a fourth aspect of the present invention, there is provided the leak-corresponding low power semiconductor integrated circuit inspection method according to the third aspect of the present invention, wherein the function block designated as the inspection target includes, An inspection power supply step for controlling the high threshold transistor to turn off and supplying power from the inspection power supply terminal to the pseudo power supply line of the corresponding functional block via the diode, and a function block not designated as the inspection target A normal power supply step for supplying power from the normal power supply terminal to the pseudo power supply line of the corresponding functional block by turning on the transistor for energization control by a designation signal from the inspection target designating means, According to whether the diode is interposed on the high potential side or the low potential side of the functional block, the normal power supply terminal has an inspection power supply. A constant voltage supply step for applying a high or low voltage that does not generate a current flowing through a diode connected to a pseudo power supply line other than the functional block that is the inspection target, and the constant voltage supply step, compared to a child. A leakage current amount measuring step for measuring the leakage current amount of the inspection power supply terminal, a comparison step for comparing the measurement value of the leakage current amount measurement step with a predetermined value, and a result of the comparison step, When the measured value is greater than or equal to a predetermined value, the leakage-corresponding low current semiconductor integrated circuit inspection method includes a determination step of determining that the functional block to be inspected is defective.
[0039]
With the above configuration, the following operation is performed as an inspection of the leak-compatible low power semiconductor integrated circuit according to the third aspect of the present invention.
In the power supply step for inspection, the functional block designated as the inspection target is turned off, and power is supplied from the inspection power supply terminal to the pseudo power supply line via the diode.
In the normal power supply step, for functional blocks that are not specified as inspection targets, the power supply control transistor is turned on by a specification signal from the inspection target specifying means, and the normal power is supplied to the pseudo power supply line of the corresponding functional block. Supply power from the terminal.
[0040]
Compared with the inspection power supply terminal, the normal power supply terminal has a function block other than the function block to be inspected, according to whether the diode is interposed on the high potential side or low potential side of the functional block in the constant voltage supply step. A constant voltage that is high or low (interposition on the low voltage side) is applied so that no current flows through the diode connected to the pseudo power supply line (interposition on the high voltage side).
In the leakage current amount measurement step, the leakage current amount of the inspection power supply terminal is measured while the constant voltage supply step is performed.
In the comparison step, the measurement value in the leakage current amount measurement step is compared with a predetermined value.
In the determination step, if the measurement value is equal to or greater than a predetermined value as a result of the comparison step, the functional block to be inspected is determined to be defective because a failure that causes a leakage current has occurred.
[0041]
According to a fifth aspect of the present invention, there is provided a functional block set including a functional block and a pseudo power supply line for supplying high-potential side or low-potential side power to the functional block, and the inspection target among the plurality of functional blocks. Inspection target specifying means for outputting a signal for specifying a functional block, inspection power supply terminals for supplying power to the pseudo power supply line of the functional block to be inspected specified by the inspection target specifying means, and the inspection target specification A normal power supply terminal that supplies power to a pseudo power supply line of a functional block that is not designated as a test target in the means, and is interposed between the test power supply terminal and each of the pseudo power supply lines. Those connected to the pseudo power supply line of the functional block designated as the inspection target by the presence or absence of the designation signal are controlled to be on, and the functional block not designated as the inspection target is controlled. Those connected to the pseudo power supply line are controlled to be turned off, and power is supplied between the energization control transistor provided for each functional block set and the normal power supply terminal and each pseudo power supply line. The leakage-compatible low-power semiconductor integrated circuit has a predetermined high-threshold diode provided for each functional block set.
[0042]
With the above configuration, the following operations are performed.
There is at least one functional block set including a functional block and a pseudo power supply line that supplies high-potential side or low-potential side power to the functional block.
The inspection object designating means outputs a signal for designating the functional block to be inspected among the plurality of functional blocks to the corresponding energization control transistor.
The inspection power supply terminal supplies power to the pseudo power supply line of the functional block to be inspected designated by the inspection subject designating means.
The normal power supply terminal supplies power to the pseudo power supply line of the functional block that has not been specified as the inspection target by the inspection target specifying means.
[0043]
For each functional block set, the conduction control transistor interposed between the normal power supply terminal and each pseudo power supply line is simulated for the functional block specified as the inspection target by the presence or absence of the specified signal from the inspection target specifying means. Those connected to the power supply line are controlled to be turned on, and those connected to the pseudo power supply line of the functional block not designated as the inspection target are controlled to be turned off.
For each functional block set, a diode having a predetermined threshold is interposed between the inspection power supply terminal and each pseudo power supply line in the direction in which power is supplied.
[0044]
According to a sixth aspect of the present invention, there is provided the leak-corresponding low power semiconductor integrated circuit inspection method according to the fifth aspect, wherein the inspection target specifying means is connected to the pseudo power supply line of the functional block specified as the inspection target. In accordance with a designation signal, the power supply control step for controlling the energization control transistor to be turned on and supplying power from the inspection power supply terminal, and the pseudo power supply line of the functional block not designated as the inspection target are connected with the diode. Through the normal power supply step for supplying power from the normal power supply terminal and whether the conduction control transistor is interposed on the high potential side or the low potential side of the functional block. Compared to the power supply terminal, a current that flows through the diode connected to the pseudo power supply line other than the functional block subject to inspection is generated. A constant voltage supply step for providing a high or low voltage as high as possible, a leakage current amount measurement step for measuring a leakage current amount of the inspection power supply terminal during the constant voltage supply step, and the leakage current amount measurement step A comparison step for comparing the measured value with a predetermined value, and a determination step for determining that the functional block to be inspected is defective if the measurement value is equal to or greater than the predetermined value as a result of the comparison step. This is a method for inspecting a leakage-compatible low current semiconductor integrated circuit characterized by the above.
[0045]
With the above configuration, the following operation is performed as the inspection method for the leak-compatible low-power semiconductor integrated circuit according to claim 5.
In the inspection power supply step, the energization control transistor is controlled to be turned on by the designation signal from the inspection object designation means to the pseudo power supply line of the functional block designated as the inspection object, and power is supplied from the inspection power supply terminal.
[0046]
In the normal power supply step, power is supplied from the normal power supply terminal to the pseudo power supply line of the functional block not designated as the inspection target through a diode.
Compared to the normal power supply terminal, the test power supply terminal has a function other than the function block to be inspected according to whether the transistor is interposed on the high potential side or low potential side of the function block in the constant voltage supply step. A constant voltage that is high or low enough not to generate current flowing through the diode connected to the pseudo power supply line is applied.
[0047]
In the leakage current amount measurement step, the leakage current amount of the inspection power supply terminal is measured while the constant voltage supply step is performed.
In the comparison step, the measurement value in the leakage current amount measurement step is compared with a predetermined value.
In the determination step, if the measurement value is equal to or greater than a predetermined value as a result of the comparison step, the functional block to be inspected is determined to be defective.
[0048]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the embodiments.
(First embodiment)
FIG. 3 is an electrical circuit diagram showing a part of the schematic configuration of the MT-CMOS semiconductor integrated circuit in the first embodiment of the present invention.
[0049]
As shown in this figure, a power supply terminal 301 that supplies a high-potential-side voltage for operation and a power-supply terminal 302 that provides a low-potential-side voltage are composed of low threshold transistors, and a pseudo power supply A functional block (illustrated as a logic circuit) 307 for interposing the line 305 and the pseudo power supply line 306 on the high potential side and the low potential side is provided. High threshold transistors 303 and 304 are interposed between the power supply terminal 301 and the pseudo power supply line 305 and between the power supply terminal 302 and the pseudo power supply line 306, respectively. Further, the inspection power supply terminals 308 and 309 are connected to the pseudo power supply lines 305 and 306, respectively.
[0050]
FIG. 1 shows an inspection procedure in the present embodiment. Hereinafter, a method for inspecting the semiconductor integrated circuit of FIG. 3 will be described based on this flowchart.
(Step 101) First, the high threshold transistor is turned on. As a result, voltage can be supplied from the power supply terminals 301 and 302 to the pseudo power supply lines 305 and 306 via the high threshold transistors 303 and 304, respectively.
[0051]
(Step 102) Next, resistances between the power supply terminal 301 and the inspection power supply terminal 308 and between the power supply terminal 302 and the inspection power supply terminal 309 are measured. If there is no failure in the semiconductor integrated circuit, the low resistance state should be between the power supply terminal 301 and the inspection power supply terminal 308 and between the power supply terminal 302 and the inspection power supply terminal 309.
(Step 103) The measured resistance value is compared with a predetermined value which is a predetermined value which is a low value indicating normality, which is obtained in advance through actual results and calculations. If the measured resistance value is lower than the predetermined value, the semiconductor integrated circuit is passed. On the other hand, if it is high, it is rejected as an on failure of the high threshold transistor.
[0052]
As described above, according to the present embodiment, the power supply terminal for inspection is provided on the pseudo power supply line, and the resistance between the power supply terminal and the power supply terminal for inspection is measured. Whether there is a failure that prevents the supply of voltage from the power supply terminal to the pseudo power supply line due to disconnection of the connection line to the power supply terminal, disconnection of the connection line to the pseudo power supply line, failure of the control signal line, etc. It becomes easy to inspect or further identify any failure.
In this embodiment, the high threshold transistor and the pseudo power supply line are provided on both the high potential side and the low potential side. However, even in the case where only one of them is provided, the resistance measurement is similarly performed. Inspection and failure location can be specified.
[0053]
(Second Embodiment)
Next, as in the first embodiment, the second embodiment of the present invention will be described with respect to the semiconductor integrated circuit inspection method of FIG.
FIG. 2 shows an inspection procedure in the present embodiment. Hereinafter, a method for inspecting the semiconductor integrated circuit of FIG. 3 will be described based on this flowchart.
[0054]
(Step 201) First, the high threshold transistor is turned off. As a result, the power supply terminals 301 and 302 and the corresponding pseudo power supply lines 305 and 306 are in a high impedance state.
(Step 202) Next, in order to confirm the high impedance state, a voltage is applied between the power supply terminal 301 and the inspection power supply terminal 308 and between the power supply terminal 302 and the inspection power supply terminal 309.
[0055]
(Step 203) The leakage current between each is measured. This measurement may be performed on either the power supply terminal side or the inspection power supply terminal side. If there is no failure in the semiconductor integrated circuit, the leakage current amounts between the power supply terminal 301 and the inspection power supply terminal 308 and between the power supply terminal 302 and the inspection power supply terminal 309 are in a high impedance state. Should be small.
(Step 204) Finally, the measured leakage current amount is compared with a predetermined value as in the first embodiment. When the value is smaller than the predetermined value, the semiconductor integrated circuit is accepted. When the value is larger, it is determined as a defective product due to an off failure of the high threshold transistor.
[0056]
As described above, according to the present embodiment, an inspection power supply terminal is provided on the pseudo power supply line, and the amount of leakage current between the power supply terminal and the inspection power supply terminal is measured, thereby providing a high threshold value. It becomes easy to inspect the presence or absence of a failure in which a voltage is always supplied from the power supply terminal to the pseudo power supply line due to a short circuit between the source and drain of the transistor, a failure of the control line, or the like.
In this embodiment, the high threshold voltage transistor and the pseudo power supply line are provided on both the high potential side and the low potential side. Inspection by measuring current is possible.
[0057]
(Third embodiment)
Next, a third embodiment of the present invention will be described.
FIG. 4 is an electric circuit diagram showing a part of the schematic configuration of the semiconductor integrated circuit in the third embodiment, which is basically the same as that shown in FIG. 9 as a conventional example. is there. For this reason, the same code | symbol is attached | subjected to the same component.
However, the difference is that the MOS transistors 9061 and 9062 for controlling the supply of voltage from the inspection power supply terminal 902 to the functional block are replaced with diodes 4011 and 4012, and the control signal lines for the MOS transistors 9061 and 9062 are therefore eliminated. For this reason, the configuration of the control circuit itself is of course simplified.
[0058]
4 shows the case where the inspection power supply terminal 902 is provided on the high potential side of the functional block. When the inspection power supply terminal 902 is provided on the low potential side of the functional block, the diode 4011, The direction of 4012 is reversed.
FIG. 5 shows an inspection procedure in the present embodiment. Hereinafter, based on this flowchart, a method for inspecting the semiconductor integrated circuit of FIG. 4 will be described.
[0059]
(Step 501) First, the functional block to be inspected is selected by the control signal 900. Here, it is assumed that the function block 9041 is selected as a target. As a result, the control circuit 903 sets the transistor 9051 for energization control, leakage prevention, and inspection target designation so that power is supplied from the normal power supply terminal 901 to the functional blocks 9042 other than the inspection target functional block 9041. Turn off, turn on 9052.
(Step 502) Next, the power of the function block 9041 to be inspected is supplied from the inspection power supply terminal 902 via the diode 4011.
[0060]
(Step 503) Power is supplied from the normal power supply terminal 901 to the functional block 9042 not to be inspected via the conduction control transistor 9052. At this time, if the inspection power supply terminal 902 is provided on the high potential side (low potential side) of the functional block, energization is performed so that no current flows through the paths of the inspection power supply terminal 902, the diode 4012, and the pseudo power supply line 9072. Considering the voltage drop of the control transistor 9052, a voltage sufficiently higher (lower) than the inspection power supply terminal 902 is applied to the normal power supply terminal 901.
[0061]
(Step 504) The semiconductor integrated circuit is caused to function until the internal state of the functional block 9041 reaches a desired state for inspection.
(Step 505) In a steady state in a desired state of the functional block 9041, the amount of leakage current is measured at the inspection power supply terminal 902.
(Step 506) Finally, the measured leakage current amount is compared with a predetermined value. When the measured leakage current amount is smaller than the predetermined value, the semiconductor integrated circuit is accepted, and when it is larger, an abnormal leakage current is present in the functional block 9041. It is determined that the defective product is defective.
[0062]
As described above, according to the present embodiment, the power supply control that has been performed by the two high threshold transistors and the two control signal lines for each functional block that has been conventionally divided is used for one energization control. In many cases, this is possible with a high threshold transistor, one diode, and one control signal line.
As a result, the required area on the integrated circuit can be reduced, leading to a reduction in manufacturing cost.
[0063]
In this embodiment, whether the functional block is good or bad is determined by measuring the leakage current at the inspection power supply terminal 902. However, the amount of leakage current flowing through the inspection power supply terminal 902 inside the semiconductor integrated circuit is measured. A current measuring unit that outputs the determination signal as a result to the outside may be provided, and the determination may be made based on the output signal. Further, by using the MOS transistors 9051 and 9052 in this embodiment as high threshold transistors and the functional blocks 9041 and 9042 as low threshold transistors, the same can be realized in the MT-CMOS semiconductor integrated circuit. .
[0064]
In step 505, the signal state inside the functional block, that is, the path through which current leaks changes depending on the on / off state of the transistor, so that the circuit is set to a desired state for a specific fault inspection. Since it is necessary to determine this route, and in order to inspect various routes, it is necessary to set them in various states, so it goes without saying that a procedure manual for these is prepared in advance. However, this is different for each functional block, and since it is not directly related to the gist of the present invention, description thereof is omitted.
[0065]
(Fourth embodiment)
A fourth embodiment of the present invention will be described.
FIG. 6 is an electrical circuit diagram illustrating a part of the schematic configuration of the semiconductor integrated circuit according to the fourth embodiment. This electric circuit is almost the same as that shown as 1 in the conventional example in FIG. For this reason, the same code | symbol is attached | subjected to the same component. However, the difference is that the MOS transistors 9051 and 9052 for controlling the supply of voltage from the normal power supply terminal 901 to the functional block (logic circuit) are replaced with the diodes 6011 and 6012 and the control signals for the MOS transistors 9051 and 9052 are eliminated. To do.
FIG. 6 shows the case where the inspection power supply terminal 902 is provided on the high potential side of the functional block. When the inspection power supply terminal 902 is provided on the low potential side of the functional block, the diode 6011, The direction of 6012 is reversed.
[0066]
FIG. 7 shows an inspection procedure in the present embodiment. Hereinafter, a method for inspecting the semiconductor integrated circuit shown in FIG. 6 will be described based on this flowchart. (Step 701) First, a function block to be inspected is selected by the control signal 900. Here, the function block 9041 is selected as a target. For this reason, the control circuit 903 has a test power supply terminal connected to the test target function block 9041. 902 In order to supply more power, the conduction control transistor 9061 is turned on, and similarly 9062 is turned off.
(Step 702) Next, power to the function block 9041 to be inspected is supplied from the inspection power supply terminal 902 via the conduction control transistor 9061.
[0067]
(Step 703) Power is supplied to the function blocks 9042 other than the inspection target function block 9041 from the normal power supply terminal 901 via the diode 6012. At this time, if the inspection power supply terminal 902 is provided on the high potential side (low potential side) of the functional block, energization is performed so that no current flows through the path of the normal power supply terminal 901, the diode 6011, and the pseudo power supply line 9071. Considering the voltage drop of the control transistor 9061, a voltage sufficiently higher (lower) than the normal power supply terminal 901 is applied to the inspection power supply terminal 902.
(Step 704) The semiconductor integrated circuit is caused to function until the internal state of the functional block 904A reaches a desired state for inspection.
[0068]
(Step 705) In the steady state in the desired state of the functional block 9041, the leakage current amount is measured at the inspection power supply terminal 902.
(Step 706) Finally, the measured value of the leakage current is compared with a predetermined value. If the measured value is smaller than the predetermined value, the semiconductor integrated circuit is accepted. If the measured value is larger, an abnormal leakage current is detected in the function block 9041. It is determined that the product is defective and has a failure.
[0069]
As described above, according to the present embodiment, similarly to the third embodiment, the power supply control conventionally performed by two transistors and two control signal lines for each functional block divided. However, it is possible to use one energization control and, in many cases, a high threshold transistor, one diode, and one control signal line. As a result, the required area on the integrated circuit can be reduced, leading to a low manufacturing cost.
[0070]
In this embodiment, the leakage current is measured at the inspection power supply terminal 902, and thereby the quality of the functional block is determined. However, the amount of leakage current flowing through the inspection power supply terminal 902 inside the semiconductor integrated circuit is measured. A current measuring unit that outputs a signal of the determination result to the outside is provided, and a determination is made based on the presence or absence of this signal (specifically, a circuit that outputs 1 at a certain current or more is configured in the LSI. Of course, in a functional block incorporating a low threshold transistor of several tens of thousands to 10 million or more and its group, the cost can be neglected even if such an LSI is incorporated a little.) is there.
[0071]
In the present embodiment, the MOS transistors 9061 and 9062 are high threshold transistors, and the functional blocks 9041 and 9042 are low threshold transistors, so that the same applies to the MT-CMOS semiconductor integrated circuit. Can be implemented.
[0072]
Although the present invention has been described based on some embodiments, it is needless to say that the present invention is not limited to the above embodiments. For example, the following may be used.
(1) In the first embodiment and the like, at least a part of the high threshold transistor and the conduction control transistor are connected in series, so to speak, a plurality of medium threshold transistors in series. Connected.
(2) In the third embodiment or the like, an on failure and an off failure of the energization control transistor are inspected.
[0073]
(3) The threshold voltage of the high threshold transistor and the low threshold transistor is mainly about 1 to 5 V at the time of filing of the present application. It is about.
Accordingly, “sufficiently low voltage” in the embodiments and the like means that “the P-side terminal is lower than the N-side terminal in consideration of a voltage drop in the wiring and the like” This is not limited to a specific numerical range.
Further, the leak current value and the like are specifically described in, for example, the aforementioned IEICE Technical Report ICD93-107 (1993-10), but of course are not limited to these values.
[0074]
【The invention's effect】
As described above, according to the present invention, the disconnection of the connection line to the power supply terminal of the high threshold transistor, whether the inspection at the time of shipment inspection in the factory or the repair for the request from the user, the pseudo power supply It is possible to easily inspect a failure in which voltage cannot be supplied from the power supply terminal to the pseudo power supply line due to disconnection of the connection line to the line, failure of the control signal line, or the like.
[0075]
Further, it is possible to easily inspect a failure in which a voltage is always supplied from the power supply terminal to the pseudo power supply line due to a short-circuit failure between the source and drain of the high threshold transistor, a control line failure, or the like.
Eventually, it becomes possible to reduce the manufacturing defects of the subsequent products based on the data obtained from this, and ultimately the manufacturing cost is reduced.
In addition, the required area on the integrated circuit can be reduced, and the manufacturing cost is reduced from this aspect.
[0076]
Furthermore, in the third and fourth embodiments, since the appropriate voltage is automatically applied to the functional blocks that are not to be inspected by the diode, it is easy to measure the leak current, and the inspection object to be inspected. There is also little danger that the circuit is destroyed by the inspection voltage due to an on / off malfunction of the energization control transistor of the other functional block.
[Brief description of the drawings]
FIG. 1 is a diagram (flow chart) showing an inspection procedure in a first embodiment of the present invention;
FIG. 2 is a diagram showing an inspection procedure in the second embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a semiconductor integrated circuit in the first and second embodiments of the present invention.
FIG. 4 is a diagram showing a configuration of a semiconductor integrated circuit according to a third embodiment of the present invention.
FIG. 5 is a diagram showing an inspection procedure in the third embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of a semiconductor integrated circuit according to a fourth embodiment of the present invention.
FIG. 7 is a diagram showing an inspection procedure in the fourth embodiment of the present invention.
FIG. 8 is a diagram of an example of a conventionally proposed semiconductor integrated circuit.
FIG. 9 is a diagram of another example of a conventionally proposed semiconductor integrated circuit.
[Explanation of sign]
301, 302 Power supply terminal
303, 304 high threshold transistor
305, 306 pseudo power line
805, 806 Same as above
307, 9041, 9042 Logic circuits as functional blocks
308, 309, 902 Power supply terminals for inspection
4011, 4012 Diode
6011, 6012 Same as above
801 High side power supply terminal
802 Low power terminal
900 Control signal
901 Normal power supply terminal
903 control circuit
9051, 9052 MOS transistors
9061, 9062 Same as above

Claims (6)

The first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, the first terminal and the second terminal are driven by power from the second terminal, and a plurality of low terminals A functional block configured by arranging a threshold transistor, and interposed between the first terminal and the functional block, and the connection state between the first terminal and the functional block is turned on by switching between on and off. The high-threshold transistor that is switched between ON and OFF and the second terminal are interposed between the functional block and the connection state between the second terminal and the functional block is switched ON and OFF by switching ON and OFF. When at least one high threshold transistor to be switched and a high threshold transistor are interposed, the first terminal or the second terminal corresponding to the high threshold transistor is provided. And when there is no high threshold transistor, a total of two power lines connecting the first terminal or the second terminal and the functional block, a high threshold transistor, At least one pseudo power supply line connecting between functional blocks, at least one inspection terminal connected to the pseudo power supply line, and control means for controlling on / off switching of the high threshold transistor. In the low-power semiconductor integrated circuit with leakage current provided,
An on control step of turning on the high threshold transistor by the control means;
An inspection for measuring a resistance between the first terminal or the second terminal connected to the high-threshold transistor that is turned on after the on-control step and the corresponding inspection terminal. Steps,
A transistor determination step for determining that the high-threshold transistor that is controlled to be on in the leakage-compatible low-power semiconductor integrated circuit is defective when the resistance value in the inspection step is equal to or greater than a predetermined value. A method for inspecting a leakage-compatible low-power semiconductor integrated circuit. The first terminal for supplying the high potential side voltage, the second terminal for supplying the low potential side voltage, the first terminal and the second terminal are driven by power from the second terminal, and a plurality of low terminals A functional block configured by arranging a threshold transistor, and interposed between the first terminal and the functional block, and the connection state between the first terminal and the functional block is turned on by switching between on and off. The high-threshold transistor that is switched between ON and OFF and the second terminal are interposed between the functional block and the connection state between the second terminal and the functional block is switched ON and OFF by switching ON and OFF. When at least one high threshold transistor to be switched and a high threshold transistor are interposed, the first terminal or the second terminal corresponding to the high threshold transistor is provided. And when there is no high threshold transistor, a total of two power lines connecting the first terminal or the second terminal and the functional block, a high threshold transistor, At least one pseudo power supply line connecting between functional blocks, at least one inspection terminal connected to the pseudo power supply line, and control means for controlling on / off switching of the high threshold transistor. In the low-power semiconductor integrated circuit with leakage current provided,
An off control step of turning off at least one of the high threshold transistors by at least one of the high threshold transistors by the control means;
A potential applying step of applying different potentials to the first terminal or the second terminal connected to the high-threshold transistor that is turned off after the off control step and the corresponding inspection terminal; ,
A leakage current measuring step of measuring a leakage current between the first terminal or the second terminal to which a different potential is applied after the potential applying step and the inspection terminal;
A function block determination step for determining that the high-threshold transistor that is controlled to be off of the leakage-compatible low-power semiconductor integrated circuit is defective when the measurement value in the leakage current measurement step is equal to or greater than a predetermined value; An inspection method for a leak-proof low-power semiconductor integrated circuit, comprising: A functional block set comprising a functional block and a pseudo power supply line that supplies power to the functional block on the high potential side or the low potential side;
Inspection object specifying means for outputting a signal for specifying a functional block to be inspected among the plurality of functional blocks;
An inspection power supply terminal for supplying power to the pseudo power supply line of the functional block to be inspected designated by the inspection subject designating means;
A normal power supply terminal that supplies power to the pseudo power supply line of the functional block that is not designated as the inspection target by the inspection target specifying means;
Controlled to turn off the ones connected between the normal power supply terminal and each of the pseudo power supply lines and connected to the pseudo power supply line of the functional block designated as the inspection target by the presence / absence of the designation signal from the inspection target designating means Are connected to the pseudo power supply line of the functional block not designated as the inspection target, and are controlled to be ON, and an energization control transistor provided for each functional block set,
Leakable type characterized by having a diode provided between the inspection power supply terminal and each of the pseudo power supply lines in a direction in which power is supplied and provided for each functional block set Low power semiconductor integrated circuit. Specify a function block set consisting of a function block and a pseudo power supply line that supplies power to the function block on the high potential side or the low potential side, and a function block in the function block set that is to be inspected Inspection target specifying means for outputting a signal for inspection, an inspection power supply terminal for supplying power to the pseudo power supply line of the functional block to be inspected specified by the inspection target specifying means, and not specified as an inspection target by the inspection target specifying means A normal power supply terminal for supplying power to the pseudo power supply line of the function block, and the normal power supply terminal and each of the pseudo power supply lines, and are designated as inspection targets by the presence or absence of a designation signal from the inspection target designating means. Those connected to the pseudo power supply line of the function block are controlled to be turned off, and those connected to the pseudo power supply line of the function block not designated for inspection are turned on. And a power supply control transistor provided for each functional block set, an inspection power supply terminal and each of the pseudo power supply lines interposed in the direction in which power is supplied, and for each functional block set An inspection method for a leak-proof low-power semiconductor integrated circuit having a provided diode,
For the functional block designated as the inspection target, the conduction control transistor provided in the functional block set is controlled to be turned off, and the pseudo power supply line of the corresponding functional block is connected to the functional power block through the diode from the inspection power supply terminal. An inspection power supply step for supplying power;
For functional blocks that have not been designated as inspection targets, the energization control transistor is controlled to be turned on by a designation signal from the inspection subject designation means, and power is supplied from the normal power supply terminal to the pseudo power supply line of the corresponding functional block. A normal power supply step to supply;
According to whether the diode is interposed on the high potential side or the low potential side of the functional block, the normal power supply terminal has a pseudo power supply line other than the function block to be inspected as compared to the inspection power supply terminal. A constant voltage supply step for providing a high or low voltage that does not generate a current flowing through a diode connected to
A leakage current amount measuring step for measuring a leakage current amount of the inspection power supply terminal during the constant voltage supply step;
A comparison step for comparing the measurement value of the leakage current amount measurement step with a predetermined value,
A leakage-corresponding low-current semiconductor integrated circuit comprising: a step of determining that the functional block to be inspected is defective when the measured value is equal to or greater than a predetermined value as a result of the comparison step Inspection method. A functional block set comprising a functional block and a pseudo power supply line that supplies power to the functional block on the high potential side or the low potential side;
Inspection object specifying means for outputting a signal for specifying a functional block to be inspected among the plurality of functional blocks;
An inspection power supply terminal for supplying power to the pseudo power supply line of the functional block to be inspected designated by the inspection subject designating means;
A normal power supply terminal that supplies power to the pseudo power supply line of the functional block that is not designated as the inspection target by the inspection target specifying means;
Those connected between the inspection power supply terminal and each pseudo power supply line and connected to the pseudo power supply line of the functional block designated as the inspection object by the presence / absence of the designation signal from the inspection object designating means are turned on Are connected to the pseudo power supply line of the functional block that is not designated as the inspection target, are controlled to be off, and the energization control transistor provided for each functional block set,
Leakable type characterized by having a diode provided between each of the normal power supply terminals and each of the pseudo power supply lines in a direction in which power is supplied and provided for each functional block set Low power semiconductor integrated circuit. Specify a function block set consisting of a function block and a pseudo power supply line that supplies power to the function block on the high potential side or the low potential side, and a function block in the function block set that is to be inspected Inspection target specifying means for outputting a signal for inspection, an inspection power supply terminal for supplying power to the pseudo power supply line of the functional block to be inspected specified by the inspection target specifying means, and not specified as an inspection target by the inspection target specifying means The normal power supply terminal that supplies power to the pseudo power supply line of the function block, and the inspection power supply terminal and each pseudo power supply line are specified as inspection targets depending on the presence or absence of a designation signal from the inspection target designating means. Those connected to the pseudo power supply line of the functional block are controlled to be turned on, and those connected to the pseudo power supply line of the functional block not designated for inspection are controlled to be turned off. In addition, an energization control transistor provided for each functional block set, a normal power supply terminal and each pseudo power supply line are interposed in the direction in which power is supplied, and provided for each functional block set. An inspection method for a leak-proof low-power semiconductor integrated circuit having a diode,
A power supply for inspection that supplies power from the inspection power supply terminal by controlling the energization control transistor to be turned on by a designation signal signal from the inspection object designation means to the pseudo power supply line of the functional block designated as the inspection object Steps,
A normal power supply step of supplying power from the normal power supply terminal to the pseudo power supply line of the functional block not designated as the inspection target via the diode;
According to whether the transistor is interposed on the high potential side or the low potential side of the functional block, the inspection power supply terminal has a pseudo power supply line other than the function block to be inspected compared to the normal power supply terminal. A constant voltage supply step for providing a high or low voltage that does not generate a current flowing through a diode connected to
A leakage current amount measuring step for measuring a leakage current amount of the inspection power supply terminal during the constant voltage supply step;
A comparison step for comparing the measurement value of the leakage current amount measurement step with a predetermined value,
A leakage-corresponding low-current semiconductor integrated circuit comprising: a step of determining that the functional block to be inspected is defective when the measured value is equal to or greater than a predetermined value as a result of the comparison step Inspection method.