JPH0997874A - Method for testing semiconductor device and semiconductor device applicable to it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for testing semiconductor device which makes it possible to make an alternating current action and a direct current measurement and a semiconductor device which is applicable to the method. SOLUTION: A bidirectionally operating transistor 1 to which electric currents flow from two directions, an oscillation signal means 3 which impresses oscillation signals of opposite phases upon the transistor 1, and an oscillation signal connecting means 4 which controls the connection between the transistor 1 and means 2 are provided. The means 2 is a circuit constituting part of a ring oscillator and, when the means 4 connects the transistor 1 and means 2 to each other, the ring oscillator is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the characteristics of a semiconductor device and a semiconductor device provided with a function for evaluating the characteristics, and more particularly, to a method and an evaluation method which enable the evaluation in a state close to an actual use state. The present invention relates to a semiconductor device that enables such a thing.

[0002]

2. Description of the Related Art In recent years, semiconductor integrated circuits (ICs) have been miniaturized, highly integrated, and their operating speeds have been increased, but the deterioration of transistor characteristics has caused a problem of shortening the life of semiconductor devices. . In order to eliminate such problems, a semiconductor device is improved by conducting a test to estimate the deterioration amount and feeding back the test result, and a highly reliable semiconductor device with less deterioration is developed. . In order to enable such an improvement, a technique for accurately evaluating and measuring the deterioration of the characteristics of the semiconductor device is required.

In order to evaluate the deterioration of the characteristics of the semiconductor device as described above, it is necessary to operate the target semiconductor device and then evaluate the deterioration of the characteristics. As operating conditions, it is desirable to use under the normal operating conditions for longer than the guaranteed time.However, since the time required for the test will be too long, the semiconductor device under test is usually overloaded and then evaluated for deterioration. It was For example, a high voltage is applied to a semiconductor device, or an oscillation signal is externally input to the drain terminal of a transistor which is an element of the semiconductor device. However, this could only reproduce the deterioration in DC operation and the deterioration in low speed operation.

In particular, the amount of change in the drain current (Ids) of the transistor is used as an index for evaluating the degree of hot carrier deterioration. In the conventional acceleration test methods, the transistor is placed in a state in which a large DC current flows. A method of detecting the amount of change in drain current characteristics after holding and applying a load (stress) has been adopted.

[0005]

However, with the recent progress in speeding up of semiconductor devices, in a high-speed operating state closer to actual operation, which cannot be reproduced by evaluation of deterioration in direct current operation or deterioration in low-speed operation. It is necessary to evaluate the deterioration. Therefore, recently, BTABERT manufactured by BTA Technology Inc. is used to estimate the deterioration amount during AC operation.
Simulators such as (product name) are being used. This makes it possible to estimate the life of the VLSI device in AC operation (operation time until deterioration to a specified level).

However, under the present circumstances, these simulators are not sufficiently accurate and, moreover, cannot be said to be sufficient for evaluating the AC characteristics themselves. The present invention has been made in view of the above problems, and an object of the present invention is to realize a semiconductor device test method capable of performing AC operation and DC measurement, and a semiconductor device that enables such a test.

Furthermore, a method for accurately evaluating the amount of deterioration of hot carriers in a state close to an actual condition, realization of a semiconductor device that enables such evaluation, and a method and measures for coping with characteristic deterioration due to hot carriers. It is an object of the present invention to realize a semiconductor device.

[0008]

FIG. 1 is a diagram showing the principle configuration of the present invention. A semiconductor device and a test method therefor according to a first aspect of the present invention are a semiconductor device 100 having a bidirectional operation transistor 1 in which a current flows bidirectionally and a test method therefor. To be applied. After applying an oscillation signal of opposite phase to the bidirectional operation transistor for a predetermined time under a predetermined condition,
A physical quantity related to the characteristics of the bidirectional operation transistor is measured to determine the degree of deterioration.

As shown in (1) of FIG. 1, even if the antiphase oscillation signal is applied from the outside of the semiconductor device, as shown in (2) of FIG. 1, the antiphase oscillation signal is generated. The signal source 2 may be provided inside the semiconductor device. In order to be able to apply the oscillation signal of the opposite phase oscillation signal from the outside, it is necessary to pull out both controlled terminals to the outside so that the signals can be applied to both controlled terminals of the bidirectional operation transistor from the outside. There is.

When the opposite phase oscillation signal source 2 is provided inside, as shown in (2) of FIG. 1, when the opposite phase oscillation signal is applied, the bidirectional operation transistor 1 is set to the oscillation signal source. Connected to, and at the time of measurement, bidirectional operation transistor 1
Needs to be disconnected from the source of the oscillating signal so that it can be connected to the outside for measurement. To apply an oscillation signal of opposite phase to the bidirectional operation transistor 1, as shown in FIG. 2, the controlled terminals of the bidirectional operation transistor are connected to the outputs and inputs of the two inverting circuits (inverters), respectively. ,
An oscillating signal is applied to the input of the inverting circuit whose controlled terminal is connected to the output. More preferably, the ring oscillator is configured to include two inverting circuits.

Further, in another method, as shown in FIG.
The controlled terminal of the bidirectional operation transistor 1 is connected to the output parts of the two inverting circuits, and the oscillation signals of opposite phases are applied to the input parts of the two inverting circuits. This antiphase oscillation signal can also be generated by the ring oscillator. The deterioration of the bidirectional operation transistor 1 is evaluated by, for example, its DC characteristic.

Further, as shown in (3) of FIG. 1, a plurality of bidirectional operation transistors are provided for evaluation and reference, and when a load is applied, a load is added for evaluation, but a load is added for reference. By not adding the value and evaluating the difference, more accurate evaluation becomes possible. Furthermore, a plurality of bidirectional operation transistors for evaluation may be provided to change the load condition.

The bidirectional operation transistor may be either an N-channel type transistor or a P-channel type transistor. A ring oscillator is used to evaluate the degree of deterioration of a semiconductor device, particularly the degree of deterioration of hot carriers. In that case, the deterioration amount is evaluated by the change of the oscillation frequency of the ring oscillator.

When evaluating the oscillation frequency of the ring oscillator, a plurality of ring oscillators are provided for evaluation and reference, and when a load is applied, the evaluation is not performed for reference and the deterioration amount is caused by the difference between both oscillation frequencies. Evaluate. When polishing the measurement, measure the oscillation frequency of the evaluation ring oscillator and the reference ring oscillator at multiple temperatures, or control the temperature of the semiconductor device so that the oscillation frequency of the reference ring oscillator becomes a predetermined frequency. Then, the oscillation frequency of the evaluation ring oscillator is measured and the difference from the predetermined frequency is taken as the deterioration amount.

When one of the evaluation and the reference is being measured, the other one is not allowed to be operated so that an error due to mutual interference is eliminated. When a ring oscillator having a large number of stages is used, the frequency is lowered and a sufficient load cannot be applied. Therefore, when a load (stress) is applied, the loop is cut so that an AC pulse can be applied from the outside.
Further, this can prevent the oscillation frequency from changing with time during the stress application.

The power supply voltage near the power supply lines of the evaluation and reference ring oscillators is detected and adjusted to a predetermined value, and then the measurement is performed. As a result, it is possible to reduce the measurement error caused by the decrease in the power supply voltage caused by the decrease in frequency. An alarm means is provided to output an alarm according to the measured deterioration degree. In that case, the oscillation frequency obtained from the evaluation ring oscillator and the reference ring oscillator, or both or either of the frequencies is divided, and the frequency of the signal obtained from the evaluation ring oscillator is obtained from the reference ring oscillator. The frequency is set slightly higher than the frequency of the signal, and an alarm is issued when the frequency of the signal obtained from the evaluation ring oscillator becomes equal to or lower than the frequency of the signal obtained from the reference ring oscillator.

When carrying out the acceleration test, stricter operating conditions than normal operating conditions are applied.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 is a diagram showing the configuration of a first embodiment of the present invention. In FIG. 4, reference numeral 21 is an bidirectionally operating N-channel transistor, and 22 is an inverting circuit in which a plurality (odd number) of inverting circuits (inverters) are connected in series. And 23 is a portion for forming measurement pads P, Q,
Reference numeral 24 is a transfer gate connecting R and S to the transistor 1, 24 is a transfer gate connecting the inverting circuit 2 to the transistor 1, 25 is a transfer gate connecting the node to the ground, 26 is a buffer, and 27 is a buffer. Are transfer gates 23, 24, 25
, P is a pad for measuring the characteristics of the transistor 1, and R is a gate terminal of the transistor 21.

When a "high (H)" signal is input to the pad DC / AC of the control circuit 27 during stress application, the terminal a becomes "low (L)" and the terminal b becomes "high", and the transfer gate 24 becomes conductive and transfer gates 23 and 2
5 is cut off, the output and the input of the inverting circuit 22 are connected via the transistor 21, a ring oscillator is constituted, and oscillates. This allows the connected terminals (drain terminal and source terminal) of the transistor 1 to be tested.
Then, signals having opposite phases are alternately applied. The cycle at which the phase of this signal switches is the cycle of the ring oscillator. As a result, a high alternating stress is applied to the transistor. The oscillation frequency of the ring oscillator is amplified by the buffer 26 and can be observed at the pad U. The voltage of the condition to be evaluated is applied to the pad R. The oscillation frequency can be freely set by changing the number of stages of the inverting circuit (inverter) that constitutes the ring oscillator.

At the time of measurement, the pad DC / AC of the control circuit 27 is used.
When a "low" signal is input to the terminal a, the terminal a becomes "high", the terminal b becomes "low", the transfer gate 24 is cut off, the transistor 21 is disconnected from the inverting circuit 22, and the transfer gate 23 and 25 becomes conductive. Since the transfer gate 25 is in the conductive state and the input is fixed to GND (ground), the inverting circuit 22 is in a constant state.

In the measurement of the transistor 21, an ammeter is connected to the pad P and the pad S connected to the transistor 21 via a transfer gate having a small resistance, a bias voltage is applied, and the current is measured. At this time, the voltage applied to the transistor 21 decreases due to the resistance of the transfer gate. Therefore, the pad Q, the pad T, and the GND connected to the transistor 21 via the transfer gate having a large resistance that allows the flowing current to be ignored. A voltmeter is connected to accurately detect the voltage applied to the controlled electrode of the transistor 21. Thereby, the voltage / current characteristic of the transistor 21 can be accurately measured.

Although the transistor to be measured is an N-channel type in the first embodiment, it may be a P-channel type. This also applies to the following examples. FIG.
FIG. 6 is a diagram showing a configuration of a second exemplary embodiment of the present invention. In FIG. 5, reference numeral 31 is a bidirectionally operating transistor, 32 is a ring oscillator in which a plurality (even number) of inverting circuits (inverters) and NAND gates are connected in series, 33 is a measurement pad P, A transfer gate for connecting Q, R, S and the transistor 31.
And 35 are inverting circuits, 36 is a transfer gate connecting the inverting circuits 34 and 35 with the transistor 31, 37 is a buffer, 38 is a control circuit for the transfer gates 33 and 36, and P, Q, S , T are pads for measuring the characteristics of the transistor 31, and R is the gate terminal of the transistor 31.

At the time of stress application, if a "high" signal is input to the pad DC / AC of the control circuit 38, the terminal a becomes "low".
Then, the terminal b becomes "high", and the transfer gate 36
Are turned on, the transfer gate 33 is turned off, and the ring oscillator 32 starts oscillating. Inverting circuit 3
When a "high" signal is applied to 4, the inverting circuit 34 outputs N
The channel transistor becomes conductive, and the "low" signal is applied to the inverting circuit 35 at this time, so the inverting circuit 3
The P-channel transistor of No. 5 becomes conductive, and the P-channel transistor of the inverting circuit 35 and the transistor 3
A current flows from the high potential of the power supply to GND through 1 and the N-channel transistor of the inverting circuit 34.

When the phase of the ring oscillator 32 is inverted, the "low" signal is applied to the inverting circuit 34, the "low" signal is applied to the inverting circuit 35, and the P-channel transistor of the inverting circuit 34 and the inverting circuit 35 are applied. Of the inverting circuit 34 and the N-channel transistor of the inverting circuit 35 and the N-channel transistor of the inverting circuit 34 are turned on.
A current flows in the opposite direction to the above. In this way, the signal of the opposite phase is applied to the transistor 31. The cycle in which the phase of the signal is switched is the cycle of the ring oscillator, and the oscillation frequency of the ring oscillator is amplified by the buffer 36 and can be observed at the pad U. The voltage of the condition to be evaluated is applied to the pad R.

During measurement, the pad DC / AC of the control circuit 38 is used.
When a “low” signal is input to the terminal a, the terminal a becomes “high”, the terminal b becomes “low”, the transfer gate 36 is turned off, the transistor 31 is disconnected from the inverting circuits 34 and 35, and the transfer gate is disconnected. 33 becomes conductive. The measurement of the transistor 31 is performed similarly to the first embodiment.

FIG. 6 is a diagram showing the configuration of the third embodiment of the present invention. In FIG. 6, reference numeral 41 is a normally operating transistor that is not bidirectional, 42 is an oscillator circuit connected to the transistor 41, and 43 is a connection between the measurement pads P, Q, R, and S and the transistor 41. A transfer gate 44 is a transfer gate connecting the oscillation circuit 42 and the transistor 41, and a transfer gate 45
Is a transfer gate that connects the node to the ground, 46 is a buffer, 47 is a control circuit for the transfer gates 43, 44, 45, 49 is a clocked inverter that connects the oscillation circuit 42 and the transistor 41, Reference numeral 50 is a clocked inverter that connects the oscillation circuit 42 and the input pad FIN, 48 is a stress selection circuit that controls the clocked inverters 49 and 50, and GN, GP, ID, and DV measure the characteristics of the transistor 41. FIN is a pulse input pad.

When a "high (H)" signal is input to the pad DC / AC of the control circuit 47 during stress application, the terminal a becomes "low", the terminal b becomes "high", and the transfer gate 44 becomes conductive. Then, the transfer gates 43 and 45 are turned off. At this time, the pad of the stress selection circuit 48
When a "low" signal is input to PATH / RING, the terminal P becomes "high", the terminal Q becomes "low", the clocked inverter 49 becomes the operating state, and the clocked inverter 4
No. 8 is in a non-operating state, and ring oscillation occurs. When a "high" signal is input to the pad PATH / RING of the stress selection circuit 48, the terminal P becomes "low", the terminal Q becomes "high", the clocked inverter 49 becomes inactive, and the clocked inverter 49 becomes inactive. The inverter 48 enters the operating state, and by applying a high frequency signal to the pad FIN, a desired high frequency signal can be applied from the outside.

During measurement, the pad DC / AC of the control circuit 47 is used.
When a "low" signal is input to, the terminal a becomes "high", the terminal b becomes "low", the transfer gate 44 is cut off, the transistor 41 is disconnected from the ring oscillator 42, and the transfer gate 43 and 45 becomes conductive. The measurement of the transistor 41 is the same as that of the first embodiment.

FIG. 7 is a block diagram showing the structure of the fourth embodiment. In the fourth embodiment, changes in the oscillation frequency of the ring oscillator are measured in order to evaluate the deterioration of hot carriers. Moreover, two ring oscillators are provided, one for evaluation and one for reference. In FIG. 7, reference numeral 100 is a semiconductor device, 10 is an evaluation ring oscillator, and 11 is a reference ring oscillator. U is a control signal terminal for controlling the oscillation operation of the evaluation ring oscillator 10, W is a control signal terminal for controlling the oscillation operation of the reference ring oscillator 11, and X is a control signal terminal.
Is a pad for measuring the oscillation frequency of the evaluation ring oscillator 10, and Y is a reference ring oscillator 11.
Is a pad for measuring the oscillation frequency of D, D is a power supply terminal, E is a ground (GND) terminal, and F is a line drawn from a portion near the connection point of the power supply wiring to the ring oscillator for evaluation 10. And G is a line drawn from a portion near the connection point of the power supply wiring to the reference ring oscillator 11.

FIG. 8 is a flow chart showing the processing in the test in the fourth embodiment. In step 801, the reference ring oscillator 11 is stopped. Step 8
In 02, the evaluation ring oscillator 10 is operated under a predetermined condition for a predetermined time. As a result, the addition is applied only to the evaluation ring oscillator 10. In step 803,
The evaluation ring oscillator 10 is stopped.

In step 804, the semiconductor device 100 is brought to the first temperature condition. In step 805, the evaluation ring oscillator 10 is operated to measure its characteristic, in this case, the oscillation frequency. In step 806, the evaluation ring oscillator 10 is stopped. Step 8
At 07, the reference ring oscillator 11 is operated,
Measure the oscillation frequency.

In step 808, it is determined whether the measurement under all the predetermined temperature conditions has been completed.
If the measurement under all the temperature conditions has not been completed, the temperature conditions are changed in step 809 and the steps under 805 to 80 are performed until the measurement under all the temperature conditions is completed.
Repeat 9.

In step 810, the difference between the oscillation frequencies of the evaluation ring oscillator 10 and the reference ring oscillator 11 at a plurality of temperatures is evaluated. In the fourth embodiment, the evaluation ring oscillator 10 and the reference ring oscillator 1 are used.
Since 1 is provided and the load is applied to only one side and the difference after the load application is measured, the difference due to the load application becomes easy to measure. Further, since the oscillation frequency of the ring oscillator changes depending on the temperature, the difference under a plurality of temperature conditions is evaluated. This allows a more accurate evaluation.

When the oscillation frequency changes due to deterioration, the power consumption changes, and the voltage drop amount due to the power supply from the power supply wiring to the ring oscillator also changes. This means that the voltage applied to the ring oscillator changes,
When the voltage changes, the oscillation frequency naturally changes. Since accurate measurement cannot be performed with this, before measuring the oscillation frequency, the voltage applied to the evaluation ring oscillator 10 and the reference ring oscillator 11 via the pads F and G of FIG. Try to match exactly.

FIG. 9 is a flow chart showing the processing in the test of the fifth embodiment. In the fifth embodiment, a semiconductor device having the same structure as that shown in FIG. 7 is tested, but the method of utilizing the reference ring oscillator 11 is slightly different. Step 9
Since the processes up to 03 are the same as those in the fourth embodiment, the description is omitted. In step 903, the reference ring oscillator 11
To measure the oscillation frequency.

In step 904, it is determined whether the oscillation frequency of the reference ring oscillator 11 matches the specified value. If they do not match, the process proceeds to step 906, where the temperature of the semiconductor device is changed so that the oscillation frequency of the reference ring oscillator 11 matches the specified value. By repeating such processing, the oscillation frequency of the reference ring oscillator 11 is made to match the specified value.

In step 907, the ring oscillator for evaluation 10 is operated and its oscillation frequency is measured. In step 907, the difference between the oscillation frequency of the evaluation ring oscillator 10 and the specified value is calculated. This represents the amount of deterioration.
The oscillation frequency of the ring oscillator differs depending on the number of stages connected. If the oscillation frequency is too high during measurement, it is difficult to measure the oscillation frequency with high accuracy. for that reason,
The oscillation frequencies of the evaluation and reference ring oscillators cannot be made very high, but even if such an oscillation signal is applied, sufficient stress cannot be applied. There is also a problem that the oscillation frequency of the evaluation ring oscillator changes due to stress while applying a load, and the load condition also changes. The sixth embodiment is to solve such a problem. FIG. 10 is a diagram showing the configuration of the sixth embodiment.

FIG. 10 shows only the configuration of the evaluation ring oscillator 10. The reference ring oscillator 11 is shown in FIG.
It has the same configuration as 0. As is clear from comparison between FIG. 10 and FIG. 7, in the sixth embodiment, transfer gates 54a and 54b are provided before and after the inverting circuit (inverter) 51 forming the ring oscillator, and the inverting circuit 5 is provided.
The input part and the output part of 1 are transfer gates 53a and 5a.
7 is different in that it is connected to the pad via 3b. Although not shown, the control circuit 2 of FIG.
A circuit similar to that of 7 is provided separately. In FIG. 10, such a circuit is provided for only one inversion circuit 51, but it may be provided for all the inversion circuits forming the ring oscillator.

When a load is applied, a "high" signal is applied to the control circuit 27. As a result, the transfer gate 5
4a and 54b become non-conductive, the inverting circuit 51 is disconnected from the other inverting circuit that constitutes the ring oscillator, the transfer gates 53a and 53b become conductive, and the input section and the output section of the inverting circuit 51 are padded. Connected to. When a high frequency oscillator is connected to this pad, a high frequency signal is applied to the inverting circuit 51.

With the above structure, it is possible to apply a high frequency signal of any frequency, and a desired stress can be applied. At the time of measurement, a “low” signal is applied to the control circuit 27. As a result, the transfer gates 54a and 54b become conductive and the inverting circuit 51
Is connected to another inverting circuit to form a ring oscillator. At this time, the transfer gates 53a and 53b are rendered non-conductive, and the pads are separated. In this state,
The oscillation frequency is measured as in the fourth embodiment. The processing in the test is similar to the processing in FIGS. 8 and 9.

In the fourth to sixth embodiments, the oscillation frequency is measured by using an external measuring device.
In the seventh embodiment, the oscillation frequencies of the evaluation ring oscillator and the reference ring oscillator are measured and compared inside the semiconductor device, and the difference is displayed or an alarm is output when the deterioration amount exceeds a predetermined amount. In this way, you will be notified that the product has reached the end of its life and you will be prompted to replace it.

FIG. 11 is a diagram showing the configuration of the seventh embodiment. In FIG. 11, reference numeral 10 is a ring oscillator for evaluation, 11 is a ring oscillator for reference,
Reference numeral 61 is a counter for measuring the oscillation frequency of the evaluation ring oscillator 10, and reference numeral 62 is the reference ring oscillator 1.
1 is a counter that measures the oscillation frequency of 1; 63 is a count period control unit that outputs a signal indicating the count period of the counters 61 and 62; and 64 is an arithmetic circuit that calculates the difference between the count values of the counters 61 and 62. Yes, 65 is a circuit that displays the difference in the count value, 66 is the difference in the count value with a preset reference value REF,
Reference numeral 67 is a comparator that changes the output when the difference between the count values exceeds a predetermined value, and 67 is an alarm unit that issues an alarm according to the change in the output of the comparator. The alarm unit 67 may be provided not in the semiconductor device but in a system in which the semiconductor device is incorporated.

The frequencies of the evaluation ring oscillator 10 and the reference ring oscillator 10 may be measured by the counters 61 and 62 as they are, or may be counted after frequency division. Further, since the frequency of the ring oscillator decreases with deterioration, the frequency of the signal obtained from the evaluation ring oscillator is set slightly higher than the frequency of the signal obtained from the reference ring oscillator, and the counters 61 and 6
It is also possible to provide a comparator for comparing the outputs of the two and issue an alarm when the output of the counter 61 becomes smaller than the output of the counter 62.

12 and 13 are block diagrams of the hot carrier deterioration evaluation circuit of the eighth embodiment. Reference numeral 201 is a transistor group that constitutes a reference ring oscillator, 202 is a transistor group that constitutes a ring oscillator that evaluates the deterioration amount of the inverter due to hot carriers, and 203 is a ring oscillator that evaluates the deterioration amount of the loaded inverter due to hot carriers. Group of transistors, 20
Reference numeral 4 denotes a transistor group that constitutes a ring oscillator that evaluates the deterioration amount due to hot carriers in the multi-stage cell; 205 denotes a transistor group that constitutes a ring oscillator that evaluates the deterioration amount due to hot carriers in the loaded multi-stage cell;
Reference numeral 6 is an oscillation control decoder circuit section, 207 is a loop selection circuit section, 208 is a ring oscillator oscillation / external pulse input selection section, and 209 is a continuous pulse / single-shot signal selection section.
Reference numeral 0 indicates a frequency dividing circuit, 211 indicates an output terminal, and 212 indicates a power supply voltage sense terminal.

From -SEL0 of the decoder circuit unit 206-
A signal is applied to SEL2, and a circuit that oscillates is determined by the loop selection circuit unit 207 depending on the combination. In the loop selection circuit unit 207, SEL00A to SEL07A are L
In the OW state, the OUT00 signal is connected and the SEL
When 01A is HIGH, the signal of OUT01 is SEL0
When 2A is HIGH, the signal of OUT02 is connected.

When it is desired to oscillate as a ring oscillator, the RING SEL of the oscillation / input selection unit 208 is set to LO.
The HIGH signal is input to the W signal and the EXT MENABLE. When oscillating the reference ring oscillator 1,
SEL00A of the decoder circuit unit 206 is in the LOW state, S
Make EL00B LOW.

When the evaluation ring oscillator 202 is oscillated, SEL01B of the decoder circuit unit 206 is set to LO.
The W state and SEL01A are set to the HIGH state. When the AC pulse is input from the outside, the LOW signal is applied to the EXT ENABLE of the oscillation / input selection unit 208. At this time, SEL00B always becomes HIGH, the reference loop 201 does not operate, and SEL01B to SEL00B
07B is always in the LOW state, and the evaluation loops 202 to 205 are in the operable state. The selection of the loop is performed by the decoder circuit unit 206 similarly to the selection of the ring oscillator. Then, the EXT PUL of the oscillation / input selection unit 209
Input pulse signal from SE.

When the evaluation is performed by rotating a single signal,
HIGH to RING SEL in pulse / single shot selection unit 209
Apply the H signal. When a single-shot signal is input to TRIGGER, it is shaped by the chop / extension circuit and loops back the selected circuit to return. The edge of interest is captured by the edge selection circuit, and again shaped by the chop / extension circuit so that the same waveform always loops once.
The evaluation loop is selected in the same way as when evaluating the ring oscillator.

The oscillation waveform is frequency-divided through the frequency dividing circuit 210 and measured at the measuring terminal 211. The operating power supply voltage is measured at the voltage sense terminal 212.

[0050]

As described above, according to the present invention,
It becomes possible to accurately evaluate the deterioration amount of the hot carrier in a state close to the actual use condition, and it becomes possible to deal with the characteristic deterioration due to the hot carrier.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram showing an example of a basic configuration of a test signal input / output circuit for a test gate.

FIG. 3 is a diagram showing another example of the basic configuration of a test signal input / output circuit for a test gate.

FIG. 4 is a diagram showing a configuration of the first embodiment.

FIG. 5 is a diagram showing a configuration of a second exemplary embodiment.

FIG. 6 is a diagram showing a configuration of a third exemplary embodiment.

FIG. 7 is a diagram showing a configuration of a fourth exemplary embodiment.

FIG. 8 is a flowchart showing a process in a fourth embodiment.

FIG. 9 is a flowchart showing the processing in the fifth embodiment.

FIG. 10 is a diagram showing a configuration of a sixth exemplary embodiment.

FIG. 11 is a diagram showing a configuration of a seventh exemplary embodiment.

FIG. 12 is a diagram showing a part of the configuration of the eighth embodiment.

FIG. 13 is a diagram showing the rest of the configuration of the eighth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bidirectional operation transistor 2 ... Oscillation signal means 3 ... External connection means 4 ... Oscillation signal connection means 10 ... Evaluation ring oscillator 11 ... Reference ring oscillator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 21/66 H01L 27/08 321L 21/8238 27/092 (72) Inventor Naoki Yuzawa Kawasaki, Kanagawa Prefecture 1015 Kamiodanaka, Nakahara-ku, Fujitsu Limited (72) Inventor, Shunro Hiroto, Kawasaki, Kanagawa 1015 Kamikodanaka, Nakahara-ku, Kanagawa Within Fujitsu Limited (72) Inventor Kenji Nakamura 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Inside Fujitsu Limited

Claims (14)

[Claims] 1. A test method for a semiconductor device having a bidirectional operation transistor in which a current flows bidirectionally, comprising a load applying step of applying an oscillation signal of an opposite phase to the bidirectional operation transistor, and the bidirectional operation transistor. And a measuring step of determining a deterioration degree by measuring a physical quantity related to the characteristics of the semiconductor device. 2. In the load applying step, the controlled terminal of the bidirectional operation transistor is connected to an input section and an output section of a series circuit in which a plurality of inverting circuits provided inside the semiconductor device are connected in series. And forming a ring oscillator including the bidirectional operation transistor, applying an oscillation signal of an opposite phase to the bidirectional operation transistor, disconnecting the bidirectional operation transistor from the inverting circuit in the measuring step, and The method for testing a semiconductor device according to claim 1, wherein the controlled terminal of the directional transistor is connected to an external terminal of the semiconductor device, and measurement is performed through the external terminal. 3. In the load applying step, a controlled terminal of the bidirectional operation transistor is connected to an output section of two inverting circuits provided inside the semiconductor device, and the two inverting circuits are connected. An opposite phase oscillation signal is applied to each input section and an opposite phase oscillation signal is applied to the bidirectional operation transistor. In the measurement step, the bidirectional operation transistor is separated from the two inverting circuits, and The method for testing a semiconductor device according to claim 1, wherein the controlled terminal of the directional transistor is connected to an external terminal of the semiconductor device, and measurement is performed through the external terminal. 4. A plurality of the bidirectional operation transistors are provided for evaluation and reference, and in the load applying step, an oscillation signal of an opposite phase is applied to the evaluation bidirectional operation transistor to obtain the reference bidirectional operation. 7. A deterioration amount is evaluated by a difference in physical quantity between the evaluation bidirectional operation transistor and the reference bidirectional operation transistor in the measuring step without applying an antiphase oscillation signal to the operation transistor. The method for testing a semiconductor device according to any one of 1. 5. The evaluation bidirectional operation transistor is provided in plural, and the characteristic of an oscillation signal of an opposite phase applied to the evaluation bidirectional operation transistor is changed in the load applying step. Semiconductor device testing method. 6. A test method for a semiconductor device, wherein a ring oscillator is provided in a semiconductor device, and a deterioration amount of the semiconductor device is evaluated by measuring deterioration of characteristics due to operation of the ring oscillator. A method of testing a semiconductor device, comprising: a load step of operating; and a measurement step of measuring a physical quantity related to characteristics of the ring oscillator to determine a degree of deterioration. 7. The physical quantity measured in the measuring step is an oscillation frequency of the ring oscillator, a plurality of the ring oscillators are provided for evaluation and reference, and the evaluation ring oscillator is predetermined in the loading step. 7. The deterioration amount is evaluated by the difference between the oscillation frequencies of the evaluation ring oscillator and the reference ring oscillator in the measurement step, which is operated for a predetermined period of time without operating the reference ring oscillator. Semiconductor device testing method. 8. The oscillation frequency of the evaluation ring oscillator and the reference ring oscillator in the measuring step is
The semiconductor device test method according to claim 7, wherein the test is performed at a plurality of temperatures. 9. In the measuring step, the semiconductor device is temperature-controlled so that the oscillation frequency of the reference ring oscillator becomes a predetermined frequency, and the oscillation frequency of the evaluation ring oscillator is measured to obtain a predetermined frequency. The semiconductor device testing method according to claim 7, wherein the difference is the deterioration amount. 10. In the measuring step, the reference ring oscillator is not operated when the oscillation frequency of the evaluation ring oscillator is being measured, and the evaluation is performed when the oscillation frequency of the reference ring oscillator is being measured. 10. The semiconductor device testing method according to claim 7, wherein the ring oscillator for use is not operated. 11. The method of testing a semiconductor device according to claim 7, wherein in the loading step, the loop of the evaluation ring oscillator is cut, and an AC pulse is applied from the outside through the cut portion. 12. In the measuring step, a power supply voltage in the vicinity of the evaluation ring oscillator is measured outside the semiconductor device, and the power supply voltage is adjusted so that the measured value of the power supply voltage becomes a predetermined value, The semiconductor device testing method according to claim 7, wherein the oscillation frequency of the evaluation ring oscillator or the reference ring oscillator is measured. 13. A bidirectional operation transistor in which a current flows bidirectionally, an oscillation signal means for applying an oscillation signal of an opposite phase to the bidirectional operation transistor, and a connection between the bidirectional operation transistor and the oscillation signal means. A semiconductor device comprising: an oscillation signal connecting means for controlling. 14. The oscillation signal means is a circuit forming a part of a ring oscillator, and when the oscillation signal connection means connects the bidirectional operation transistor and the oscillation signal means, a ring oscillator is formed. 14. The semiconductor device according to claim 13, which is provided.