JP4753897B2 - Measuring method of semiconductor device - Google Patents

Description

  The present invention relates to a method for measuring electrical characteristics of a semiconductor device, and more particularly to a method for compensating for the influence of contact resistance between a semiconductor device and a measurement probe.

When measuring the electrical characteristics of a semiconductor device, it is a general method to measure by bringing a probe into contact with a terminal of the semiconductor device. However, since a contact resistance always exists between the terminal of the semiconductor device and the probe, the measurement accuracy has been lowered due to the influence of the contact resistance.
For example, FIG. 5 is a diagram showing an example of the output voltage Vo-output current io characteristic in a constant voltage circuit built in the semiconductor device. FIG. 5 shows a case where an overcurrent protection circuit having a U-shaped characteristic is provided in the constant voltage circuit. In FIG. 5, the output voltage Vo when the maximum output current iomax is output is Vo1.

Here, in order to measure the maximum output current iomax, a constant voltage power supply with an output voltage of Vo1 is connected to the output terminal of the constant voltage circuit, and the output current io is measured. The output terminal voltage was a voltage Vo2 larger than the voltage Vo1. As can be seen from FIG. 5, the output current io when the output terminal voltage is Vo2 is io2 smaller than the maximum output current iomax, and it can be seen that the maximum output current iomax is not measured.
The contact resistance has a greater influence on the measured value as the current value flowing through the terminal of the semiconductor device and the probe increases. Also, when many semiconductor devices are measured in the mass production process, the contact resistance changes greatly due to dust adhering to the tip of the probe or wear of the tip. Could not be treated as a resistance value.

As a method for suppressing the influence of such contact resistance, it is common to use a Kelvin probe capable of performing four-terminal measurement. However, in recent years, the terminals have become smaller with the miniaturization of semiconductor devices. It has become difficult to use probes.
For this reason, as a method of measuring by reducing the contact resistance without using a Kelvin probe, before starting the measurement, supply a current and voltage that are higher than the current and voltage used for measurement and reduce the contact resistance before measurement. There was a method of performing (see, for example, Patent Document 1).
JP 2006-10572 A

  However, the current and voltage to be supplied need to be less than or equal to the absolute maximum rating value of the semiconductor device to be measured. However, since recent semiconductor devices are operated at a low voltage, the current and voltage that can be supplied are not much. The size could not be increased, and a great effect could not be obtained.

  The present invention has been made to solve such a problem, and an object of the present invention is to obtain a semiconductor device measurement method capable of high-precision measurement without using a Kelvin probe.

A measuring method of a semiconductor device according to the present invention is a measuring method of a semiconductor device comprising a measured terminal and a measured sense terminal provided so as to have the same voltage as the measured terminal.
The set second voltage is input to the measured terminal,
Measure the voltage of the sense terminal to be measured,
Detecting a voltage difference between the voltage of the sense terminal to be measured and the second voltage;
When the voltage difference exceeds a predetermined value, the voltage value of the second voltage input to the measured terminal is corrected so that the voltage difference is less than or equal to the predetermined value,
If the voltage difference is less than or equal to the predetermined value, measure the electrical characteristics of the measured terminal ,
The semiconductor device includes an overcurrent protection circuit that lowers the output voltage and lowers the output current so that the characteristics of the output voltage and the output current form a U-shaped characteristic when the output current exceeds a predetermined value. A constant voltage circuit, and the measured terminal is an output terminal of the constant voltage circuit;
The electrical characteristic is the maximum output current value of the constant voltage circuit .

The semiconductor device measuring method according to the present invention includes a power input terminal, a power sense terminal provided to be at the same voltage as the power input terminal, a measured terminal, and the same voltage as the measured terminal. In a method for measuring a semiconductor device comprising a sense terminal to be measured provided to be,
The set first voltage is input to the power input terminal,
The set second voltage is input to the measured terminal,
Measure the voltage of the sense terminal to be measured,
Detecting a voltage difference between the voltage of the sense terminal to be measured and the second voltage;
When the voltage difference between the voltage of the measured sense terminal and the second voltage exceeds a first predetermined value, the voltage difference is input to the measured terminal so that the voltage difference is less than or equal to the first predetermined value. Correcting the voltage value of the second voltage;
Measure the voltage of the power supply sense terminal,
Detecting a voltage difference between the voltage of the power supply sense terminal and the first voltage;
When the voltage difference between the voltage of the power supply sense terminal and the first voltage exceeds a second predetermined value, the voltage input to the power supply input terminal so that the voltage difference is equal to or less than the second predetermined value. Correct the voltage value of the first voltage,
When the voltage difference between the voltage at the measured sense terminal and the second voltage is less than or equal to the first predetermined value and the voltage difference between the voltage at the power supply sense terminal and the first voltage is less than or equal to the second predetermined value Measures the electrical characteristics of the terminal to be measured.

  Specifically, the semiconductor device has a constant voltage circuit, and the measured terminal is an output terminal of the constant voltage circuit.

  In addition, the constant voltage circuit reduces the output voltage so that the characteristic of the output voltage and the output current of the constant voltage circuit forms a U-shaped characteristic when the output current of the constant voltage circuit exceeds a predetermined value. An overcurrent protection circuit for reducing the output current is provided, and the electrical characteristic is set to the maximum output current value of the constant voltage circuit.

  According to the method for measuring a semiconductor device of the present invention, the voltage difference between the voltage of the sense terminal to be measured and the second voltage input to the terminal to be measured is equal to or less than a predetermined value. Thus, the voltage value of the second voltage is corrected so that the electrical characteristics of the terminal to be measured are measured when the voltage difference becomes a predetermined value or less. Therefore, the influence of contact resistance at the terminal to be measured can be eliminated, so that high-precision measurement can be performed without using a Kelvin probe, and the semiconductor device and the terminal can be downsized.

  According to the method for measuring a semiconductor device of the present invention, the voltage difference between the voltage of the sense terminal to be measured and the second voltage input to the terminal to be measured is the first voltage. The voltage value of the second voltage is corrected so as to be equal to or less than the predetermined value, and the voltage of the power supply sense terminal provided so that the voltage difference is equal to or less than the first predetermined value and the same voltage as the power input terminal and the power supply The voltage value of the first voltage is corrected so that the voltage difference with the first voltage input to the input terminal is less than or equal to the second predetermined value, and when the voltage difference becomes less than or equal to the second predetermined value, the electrical characteristics of the terminal to be measured Was measured. From this, since it is possible to eliminate the influence of contact resistance at the terminal to be measured, high-precision measurement can be performed without using a Kelvin probe, and the semiconductor device and the terminal can be miniaturized, The influence of contact resistance at the power input terminal can also be eliminated, and more accurate measurement can be performed.

Next, the present invention will be described in detail based on the embodiments shown in the drawings.
First embodiment.
FIG. 1 is a diagram showing a configuration example of a measurement apparatus that performs the semiconductor device measurement method according to the first embodiment of the present invention.
In FIG. 1, a measuring apparatus 1 measures the electrical characteristics of a semiconductor device 10, and generates and outputs a DC voltage V1 corresponding to an input control signal, and an input Variable DC voltage source 3 that generates and outputs DC voltage V2 according to the control signal, voltage measurement circuit 4, current measurement circuit 5, and variable DC voltage sources 2 and 3 according to the measurement results of voltage measurement circuit 4 And a control circuit 6 for controlling the above operation, and further provided with connection terminals V1o, Vis, Vos and V2o.

The semiconductor device 10 includes a constant voltage circuit 11, which is a circuit to be measured, an input terminal IN, an output terminal OUT, and connection terminals ISENSE and OSENSE. The constant voltage circuit 11 forms a series regulator. The output terminal OUT is a terminal to be measured, the connection terminal OSENSE is a sense terminal to be measured, the input terminal IN is a power input terminal, and the connection terminal ISENSE is a power sense terminal.
The constant voltage circuit 11 generates a predetermined constant voltage from the input voltage Vin input to the input terminal IN, and outputs it from the output terminal OUT as the output voltage Vo.
The constant voltage circuit 11 generates a reference voltage generation circuit 12 that generates and outputs a predetermined reference voltage Vref, an error amplification circuit 13, and a current corresponding to a control signal input to the gate from the input terminal IN to the output terminal OUT. An output transistor M1 composed of an output PMOS transistor, output voltage detection resistors R1 and R2, and an overcurrent protection circuit that limits the operation of the output transistor M1 so that the current output from the output transistor M1 does not exceed a predetermined value. 14.

  In the measuring device 1, the voltage V1 is input from the variable DC power source 2 to the connection terminal V1o, and the voltage measurement circuit 4 is connected to the connection terminals Vis and Vos, respectively. Further, the voltage V2 is input from the variable DC power source 3 to the current measuring circuit 5, and the current measuring circuit 5 is connected to the connection terminal V2o. The control circuit 6 receives the measurement results from the voltage measurement circuit 4 and the current measurement circuit 5, respectively, and outputs the voltage V 1 output to the variable DC power sources 2 and 3 according to the measurement result of the voltage measurement circuit 4. And the voltage value of V2 is controlled. Note that the control circuit 6 may control the operation of the voltage measurement circuit 4 and the current measurement circuit 5.

  On the other hand, in the semiconductor device 10, an output transistor M1 is connected between the input terminal IN and the output terminal OUT, and resistors R1 and R2 are connected in series between the output terminal OUT and the ground voltage. A divided voltage Vfb obtained by dividing the output voltage Vo is output to the non-inverting input terminal of the error amplifier circuit 13 from the connection portion between the resistors R1 and R2. The reference voltage Vref is input to the inverting input terminal of the error amplifier circuit 13, and the output terminal of the error amplifier circuit 13 is connected to the gate of the output transistor M1. The output terminal of the overcurrent protection circuit 14 is connected to the gate of the output transistor M1. The connection terminal ISENSE is connected to the input terminal IN, and the connection terminal OSENSE is connected to the output terminal OUT.

When measuring the semiconductor device 10 by the measuring apparatus 1, the connection terminal V1o is connected to the input terminal IN, the connection terminal Vis is connected to the connection terminal ISENSE, the connection terminal Vos is connected to the connection terminal OSENSE, and the connection terminal V2o is connected to the output terminal OUT. They are connected using a contact such as a probe.
In such a configuration, the error amplifying circuit 13 controls the operation of the output transistor M1 so that the divided voltage Vfb becomes the reference voltage Vref, regardless of the output current io output from the output transistor M1 to the output terminal OUT. Control is performed so that the output voltage Vo is constant.

FIG. 2 is a diagram showing an example of the output voltage Vo-output current io characteristic of the constant voltage circuit 11.
As can be seen from FIG. 2, the output voltage Vo is maintained at the rated voltage from the output current io of 0 A to the predetermined value io1, but when the output current io exceeds the predetermined value io1, the overcurrent protection circuit 14 is activated. In order to limit the operation of the output transistor M1, the output voltage Vo decreases. However, the output current io continues to increase and reaches the maximum value iomax when the output voltage Vo reaches the predetermined value Vo1. Thereafter, both the output voltage Vo and the output current io decrease, and such a characteristic of the overcurrent protection circuit 14 is generally called a “F” characteristic from the shape of the graph.

The measuring device 1 is for measuring the maximum value iomax shown in FIG. 2, and the variable DC voltage source 2 is connected from the connection terminal V1o to the input terminal IN of the semiconductor device 10 to supply power to the semiconductor device 10. Supply. The voltage V2 output from the variable DC voltage source 3 is output to the connection terminal V2o via the current measurement circuit 5.
FIG. 3 is a flowchart showing an example of the operation of the measurement apparatus 1 of FIG. 1, and the measurement operation of the measurement apparatus 1 will be described with reference to FIG.
In FIG. 3, the control circuit 6 of the measuring apparatus 1 causes the variable DC voltage source 2 to output a predetermined voltage V1 to the input terminal IN of the semiconductor device 10 in step S1, and in step S2, the variable DC voltage source 3 In contrast, a predetermined voltage V2 is output to the output terminal OUT of the semiconductor device 10 which is the terminal to be measured. The control circuit 6 is set so that the voltage V2 becomes a predetermined value Vo1 with respect to the variable DC voltage source 3.

  Next, in step S3, the control circuit 6 measures the voltage value of the connection terminal OSENSE using the voltage measurement circuit 4, and in step S4, the voltage difference between the measured voltage of the connection terminal OSENSE and the voltage V2 is calculated. It is checked whether the voltage difference is within the predetermined first tolerance. If the voltage difference is within the first tolerance (Yes), the current measurement circuit 5 is used to measure the current value of the output current io in step S5. The flow is terminated with the measured value as the maximum value iomax. On the other hand, if the voltage difference exceeds the first tolerance (No) in step S4, the control circuit 6 determines that the voltage V2 is equal to the voltage corresponding to the voltage difference with respect to the variable DC voltage source 3 in step S6. After the voltage value is corrected and output to the output terminal OUT, the process returns to step S3, and the operation of step S6 is repeated until it is detected in step S4 that it is within the first tolerance.

  The voltage V1 is a first voltage, the voltage V2 is a second voltage, and the first tolerance is a first predetermined value. In FIG. 3, after the operation of step S6 is performed, the process returns to step S3. However, if it is known that the operation of step S6 is performed only once and falls within the first tolerance, the process of step S6 is performed. After performing the operation, the process may proceed to step S5. In step S2, the voltage output to the output terminal OUT is set to the predetermined value Vo1, but a voltage slightly larger than the predetermined value Vo1 is output as the voltage V2 in anticipation of a voltage drop due to contact resistance from the beginning. You may make it do. In this way, in step S4, the probability that the voltage difference exceeds the first tolerance can be reduced.

  As described above, in the measurement method of the first embodiment, when the measured voltage difference between the connection terminal OSENSE and the voltage V2 is within the predetermined first tolerance, the current measurement circuit 5 is used. The current value of the output current io was measured, and the measured value was set to the maximum value iomax. Therefore, the electrical characteristics of the semiconductor device 10 can be measured with high accuracy without using a Kelvin probe.

Second embodiment.
In the first embodiment, the contact resistance of the input terminal IN is not taken into account. However, since the input terminal IN is also affected by the contact resistance, the voltage supplied from the measuring device 1 to the input terminal IN of the semiconductor device 10 Was lower by the voltage drop due to the contact resistance. Therefore, a measurement method that takes into account the contact resistance of the input terminal IN is the second embodiment of the present invention.
Note that the configuration example of the measurement apparatus that performs the semiconductor device measurement method according to the second embodiment of the present invention is the same as that of FIG. 1, and is omitted. Hereinafter, the second embodiment will be described with reference to FIG. A method for measuring a semiconductor device will be described.

FIG. 4 is a flowchart showing a method for measuring a semiconductor device according to the second embodiment of the present invention. The measurement operation of the measuring apparatus 1 will be described with reference to FIG. In FIG. 4, the same flow as or the same flow as in FIG. 3 is denoted by the same reference numeral, and description thereof is omitted here, and only differences from FIG.
In FIG. 4, after the operations of steps S1 to S3 in FIG. 3 are performed, in step S4 in FIG. 3, if the measured voltage difference between the connection terminal OSENSE and the voltage V2 is within a predetermined first tolerance ( Yes) In step S11, the control circuit 6 uses the voltage measurement circuit 4 to measure the voltage at the connection terminal ISENSE.

  Next, in step S12, the control circuit 6 checks whether or not the measured voltage difference between the voltage of the connection terminal ISENSE and the voltage V1 is within a predetermined second tolerance, and the voltage difference is within the second tolerance. If there is (Yes), the process of step S5 in FIG. 3 is performed and this flow is terminated. If the voltage difference exceeds the second tolerance in step S12 (No), the control circuit 6 determines the voltage and voltage of the connection terminal ISENSE measured with respect to the variable DC voltage source 2 in step S13. After correcting the voltage value of the voltage V1 by a voltage corresponding to the voltage difference from V1 and outputting it to the input terminal IN, the process returns to step S3, and in step S13, until it is detected that it is within the second tolerance. Repeat the operation.

The second tolerance is a second predetermined value. Also in FIG. 4, after the operation of step S6 is performed, the process returns to step S3. However, if it is known that the operation of step S6 is performed only once and falls within the first tolerance, step S6 is performed. After performing the above operation, the process may proceed to step S11. Similarly, after performing the operation of step S13, the process returns to step S3. However, if it is known that the operation of step S13 is performed once and falls within the second tolerance, the operation of step S13 is performed. After that, the process may proceed to step S5.
In the flowchart of the second embodiment, the voltage V1 is corrected after the voltage V2 is corrected. However, the voltage V2 may be corrected after the voltage V1 is corrected. The order is not limited.

  As described above, in the measurement method according to the second embodiment, the voltage difference between the measured voltage of the connection terminal OSENSE and the voltage V2 is within the predetermined first tolerance, and the measured voltage and voltage of the connection terminal ISENSE. When the voltage difference from V1 is within the predetermined second tolerance, the current value of the output current io is measured using the current measurement circuit 5, and the measured value is set to the maximum value iomax. Thus, the electrical characteristics of the semiconductor device 10 can be measured with higher accuracy without using a Kelvin probe.

  In the first and second embodiments, the case where the maximum output current value iomax of the constant voltage circuit 11 is measured has been described as an example. However, the present invention is not limited to this, and the terminal to be measured If the relationship between the output voltage and the output current is clarified, it can be applied to all.

It is the figure which showed the structural example of the measuring apparatus which performs the measuring method of the semiconductor device in the 1st Embodiment of this invention. FIG. 2 is a diagram illustrating an example of output voltage Vo-output current io characteristics in the constant voltage circuit 11 of FIG. 1. 3 is a flowchart showing an operation example of the measuring apparatus 1 in FIG. 1. It is the flowchart which showed the measuring method of the semiconductor device in the 2nd Embodiment of this invention. It is the figure which showed the example of the output voltage Vo-output current io characteristic in the constant voltage circuit incorporated in the conventional semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2, 3 Variable DC voltage source 4 Voltage measuring circuit 5 Current measuring circuit 6 Control circuit 10 Semiconductor device 11 Constant voltage circuit 12 Reference voltage generating circuit 13 Error amplification circuit 14 Overcurrent protection circuit M1 Output transistor R1, R2 Resistance

Claims (4)

In a measurement method of a semiconductor device comprising a measured terminal and a measured sense terminal provided to have the same voltage as the measured terminal,
The set second voltage is input to the measured terminal,
Measure the voltage of the sense terminal to be measured,
Detecting a voltage difference between the voltage of the sense terminal to be measured and the second voltage;
When the voltage difference exceeds a predetermined value, the voltage value of the second voltage input to the measured terminal is corrected so that the voltage difference is less than or equal to the predetermined value,
If the voltage difference is less than or equal to the predetermined value, measure the electrical characteristics of the measured terminal ,
The semiconductor device includes an overcurrent protection circuit that lowers the output voltage and lowers the output current so that the characteristics of the output voltage and the output current form a U-shaped characteristic when the output current exceeds a predetermined value. A constant voltage circuit, and the measured terminal is an output terminal of the constant voltage circuit;
The method for measuring a semiconductor device, wherein the electrical characteristic is a maximum output current value of the constant voltage circuit . A power input terminal; a power sense terminal provided to be at the same voltage as the power input terminal; a terminal to be measured; and a sense terminal to be measured provided to be at the same voltage as the terminal to be measured. In a method for measuring a semiconductor device,
The set first voltage is input to the power input terminal,
The set second voltage is input to the measured terminal,
Measure the voltage of the sense terminal to be measured,
Detecting a voltage difference between the voltage of the sense terminal to be measured and the second voltage;
When the voltage difference between the voltage of the measured sense terminal and the second voltage exceeds a first predetermined value, the voltage difference is input to the measured terminal so that the voltage difference is less than or equal to the first predetermined value. Correcting the voltage value of the second voltage;
Measure the voltage of the power supply sense terminal,
Detecting a voltage difference between the voltage of the power supply sense terminal and the first voltage;
When the voltage difference between the voltage of the power supply sense terminal and the first voltage exceeds a second predetermined value, the voltage input to the power supply input terminal so that the voltage difference is equal to or less than the second predetermined value. Correct the voltage value of the first voltage,
When the voltage difference between the voltage at the measured sense terminal and the second voltage is less than or equal to the first predetermined value and the voltage difference between the voltage at the power supply sense terminal and the first voltage is less than or equal to the second predetermined value Is a method for measuring a semiconductor device, wherein the electrical characteristics of the terminal to be measured are measured. 3. The method of measuring a semiconductor device according to claim 2, wherein the semiconductor device has a constant voltage circuit, and the terminal to be measured is an output terminal of the constant voltage circuit.   When the output current of the constant voltage circuit exceeds a predetermined value, the constant voltage circuit lowers the output voltage so that the characteristics of the output voltage and the output current of the constant voltage circuit form a U-shaped characteristic and outputs the output voltage. 4. The method of measuring a semiconductor device according to claim 3, further comprising an overcurrent protection circuit for reducing a current, wherein the electrical characteristic is a maximum output current value of the constant voltage circuit.

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