JP2014036105A - Measuring method of semiconductor device and measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method of a semiconductor device and a measuring device which can obtain a measurement result from which influence of a stage resistance value is eliminated with a simple method.SOLUTION: A measuring method of a semiconductor device includes the steps of: acquiring a stage resistance value which is a resistance value from a prescribed position of a top face 18a of a stage 18 to a connection part 22 attached to the stage 18 and transmitting the stage resistance value to an evaluation unit 28; bringing a rear face of a semiconductor device 20 into contact with the top face 18a of the stage 18 and bringing a probe 14 into contact with a top face of the semiconductor device 20; acquiring, by the evaluation part 28, a measuring result of the semiconductor device 20 by flowing current in a route from the probe 14 to the evaluation unit 28 via the semiconductor device 20, the stage 18 and the connection part 22; and calculating, by the evaluation part 28, a corrected measuring result by correcting the measuring result so as to eliminate influence of the stage resistance value on the measuring result.

Description

  The present invention relates to a method for measuring electrical characteristics of a semiconductor device in which, for example, a power semiconductor element is formed, and a measuring instrument used therefor.

  Patent Document 1 discloses that the contact resistance between the semiconductor device and the stage fluctuates due to aging of the stage surface in contact with the semiconductor device. The technique disclosed in Patent Document 1 eliminates the influence on the measurement result of the contact resistance by dividing the stage on which the semiconductor device is installed and using the four-probe method.

Japanese Patent Publication No. 6-103708

  When current is passed through a stage in contact with the semiconductor device to measure the electrical characteristics of the semiconductor device, the resistance value of the stage (stage resistance value) contributes to the measurement result. This stage resistance value is not constant in time and place, but varies due to deterioration of the stage surface over time, overall partial contamination, or increase or decrease in surface oxide. Variations in the stage resistance value may cause variations in the measurement accuracy of the semiconductor device.

  Since the technique disclosed in Patent Document 1 uses the four-probe method, there is a problem that the structure of the measuring instrument and the evaluation process are complicated. Further, the technique disclosed in Patent Document 1 has a problem that the structure of the measuring instrument becomes complicated because it is necessary to divide the stage finely when measuring a semiconductor device in which a large number of minute power semiconductor elements are formed. .

  The present invention has been made to solve the above-described problems, and provides a semiconductor device measurement method and a measuring instrument that can obtain a measurement result that eliminates the influence of the stage resistance value by a simple method. For the purpose.

  The method for measuring a semiconductor device according to the invention of the present application acquires a stage resistance value that is a resistance value from a predetermined position on the upper surface of the stage to a connection portion attached to the stage, and transmits the stage resistance value to the evaluation unit. A step of bringing the back surface of the semiconductor device into contact with the upper surface of the stage and applying a probe to the upper surface of the semiconductor device; and the evaluation unit from the probe through the semiconductor device, the stage, and the connection unit A step of obtaining a measurement result of the semiconductor device by flowing a current through a path to the evaluation unit, and the evaluation unit corrects the measurement result so as to eliminate the influence of the stage resistance value on the measurement result. And a step of calculating the corrected measurement result.

  A measuring instrument according to the invention of the present application is connected to a probe fixed to a probe card, a stage formed of a conductive material, a connection portion attached to the stage, the probe and the connection portion, An evaluation unit that obtains a stage resistance value that is a resistance value from a predetermined position on the upper surface to the connection unit. Then, the evaluation unit obtains a measurement result obtained by passing a current from the probe through a path passing through the semiconductor device mounted on the upper surface of the stage, the stage, and the connection unit. It is characterized by being modified so as to eliminate the influence.

  According to the present invention, a measurement result excluding the influence of the stage resistance value can be obtained by a simple method.

It is a figure which shows the measuring device which concerns on Embodiment 1 of this invention. It is a top view of the stage shown in FIG. It is a figure which shows measuring a stage resistance value. It is a figure which shows measuring a stage resistance value in the position different from the case of FIG. It is a figure which shows measuring the electrical property of a semiconductor device. It is a figure which shows measuring the electrical property of a semiconductor device in the position different from the case of FIG. It is a figure which shows the measuring device which concerns on Embodiment 2 of this invention. It is a figure which shows the measuring device which concerns on Embodiment 3 of this invention. It is a top view of FIG. It is a figure which shows the measuring device which concerns on Embodiment 4 of this invention. It is a top view of the stage of FIG. 10, and its periphery. It is a flowchart which shows the measuring method of the semiconductor device which concerns on Embodiment 4 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a measuring instrument according to Embodiment 1 of the present invention. The measuring instrument 10 includes a probe card 12. A probe 14 is fixed to the lower surface of the probe card 12. A plurality of probes 14 are fixed to the probe card 12 so as to cope with a large current. It is preferable that the currents flowing through each of the plurality of probes 14 are substantially matched. A probe card connection portion 16 is attached to the upper surface of the probe card 12. The probe card connection unit 16 is electrically connected to the probe 14.

  Below the probe card 12 is a stage 18 formed of a conductive material. The stage 18 has a flat upper surface 18a. The upper surface 18a is a portion on which the semiconductor device 20 is mounted. The semiconductor device 20 is not particularly limited as long as it has a vertical structure that allows current to flow between the upper surface and the lower surface. For example, the semiconductor device 20 is a semiconductor wafer on which a plurality of IGBTs are formed.

  A connecting portion 22 is attached to the side surface of the stage 18. A stage resistance 24 having a constant stage resistance value is inevitably generated between the upper surface 18 a of the stage 18 and the connection portion 22. The stage resistance 24 is generated, for example, due to deterioration over time of the upper surface 18a of the stage 18, dirt, or a surface oxide. FIG. 2 is a plan view of the stage shown in FIG. A groove 18 b is formed on the upper surface 18 a of the stage 18. A suction port 18c, which is a hole for vacuum-sucking the semiconductor device, is formed on the inner wall of the groove 18b.

  Returning to the description of FIG. An evaluation unit 28 is connected to the connection unit 22 via a signal line 26. The evaluation unit 28 measures the semiconductor device and corrects the measurement result. The evaluation unit 28 is connected to the probe 14 via the signal line 30, the probe card connection unit 16, and the probe card 12.

  The evaluation unit 28 includes a storage unit 28a, a measurement unit 28b, a calculation unit 28c, and an output unit 28d. The storage unit 28 a is a part that stores information related to the resistance value of the stage 18. The measurement unit 28b is a part that measures the electrical characteristics of the semiconductor device. The calculation unit 28c is a part for correcting the measurement result. The output unit 28d is a part that outputs the corrected measurement result.

  A method for measuring a semiconductor device using the measuring instrument 10 will be described. First, a stage resistance value that is a resistance value from a predetermined position on the upper surface 18 a of the stage 18 to the connecting portion 22 is acquired. FIG. 3 is a diagram illustrating measuring the stage resistance value. First, while holding the probe card 12 with the arm 50, the probe 14 is applied to the upper surface 18 a of the stage 18. Then, a current is passed between the probe 14 and the connection portion 22 to acquire the stage resistance value.

  FIG. 4 is a diagram showing that the stage resistance value is measured at a position different from the case of FIG. As described above, a plurality of stage resistance values are acquired at different positions on the upper surface 18 a of the stage 18. Information about the acquired stage resistance value and the coordinates at which the stage resistance value is acquired is stored in the storage unit 28a.

  Next, electrical characteristics of the semiconductor device are measured. FIG. 5 is a diagram illustrating measuring electrical characteristics of the semiconductor device. The back surface of the semiconductor device 20 is brought into contact with the upper surface 18 a of the stage 18, and the probe 14 is applied to the upper surface of the semiconductor device 20. The probe 14 is applied to the upper surface of the semiconductor device 20 immediately above the “predetermined position” where the stage resistance value is measured. In this state, the evaluation unit 28 passes a current from the probe 14 to the evaluation unit 28 via the semiconductor device 20, the stage 18, and the connection unit 22, and acquires the measurement result of the electrical characteristics of the semiconductor device 20. This measurement is performed by the measurement unit 28b. The measurement results relate to, for example, VF (forward voltage) and VCEsat (saturation voltage), which are measurement items for applying a relatively large current.

  FIG. 6 is a diagram illustrating the measurement of the electrical characteristics of the semiconductor device at a position different from that in FIG. Here, the probe 14 is applied to the semiconductor device immediately above the place where the stage resistance is measured in FIG. As described above, a plurality of measurement results are obtained at different positions on the upper surface 18 a of the stage 18. All measurement results are associated with information on the coordinates from which the measurement results were obtained. The coordinates correspond to the coordinates indicating the place where the stage resistance value is measured.

Next, the evaluation unit 28 corrects the measurement result. Specifically, the calculation unit 28c in the evaluation unit 28 calculates (calculates) a corrected measurement result obtained by correcting the measurement result so as to eliminate the influence of the stage resistance value on the measurement result. The calculation of the corrected measurement result is performed using the stage resistance value at the position on the stage 18 where the measurement result is obtained. The corrected measurement result is calculated by the following formula 1.
Modified measurement result = Measurement result− (Stage resistance value × Bias current) Equation 1
In the calculation of the corrected measurement result based on Equation 1, the coordinates of the place where the “stage resistance value” is acquired and the coordinates of the place where the “measurement result” is acquired match. Such calculation of the corrected measurement result is performed for each place where the stage resistance value is measured. Finally, the output unit 28d of the evaluation unit 28 outputs the corrected measurement result to the outside.

  According to the semiconductor device measurement method using the measuring instrument 10 according to the first embodiment of the present invention, it is possible to obtain a corrected measurement result that is a measurement result excluding the influence of the stage resistance value. Therefore, the measurement result of the semiconductor device reflects the actual electrical characteristics of the semiconductor device. A plurality of stage resistance values are acquired at different locations on the stage 18, and the measurement results are corrected using the stage resistance values at the locations on the stage where the measurement results are obtained. Therefore, the influence on the corrected measurement result due to the variation in the stage resistance value in the stage 18 can be eliminated.

  In Embodiment 1 of the present invention, a plurality of stage resistance values are acquired, but the present invention is not limited to this. When the stage resistance value does not depend on the position of the upper surface 18a of the stage 18, one stage resistance value is used for all measurement results, stage resistance values obtained at a small number of measurement points, An average value of stage resistance values may be used.

  Various other modifications are possible. For example, the stage resistance value may be measured after obtaining the measurement result. The connecting portion 22 may be attached to a side other than the side surface of the stage 18. The stage 18 is not limited to vacuum suction, and may hold the semiconductor device by electrostatic suction.

Embodiment 2. FIG.
Since the semiconductor device measuring method and measuring instrument according to the second embodiment of the present invention have much in common with the first embodiment, the differences from the first embodiment will be mainly described. FIG. 7 is a diagram showing a measuring instrument according to Embodiment 2 of the present invention. A resistance measurement probe 60 is attached to the probe card 12. The measuring instrument according to Embodiment 2 of the present invention is characterized in that a stage resistance value is measured using a resistance measuring probe 60.

  The resistance measurement probe 60 is formed to extend longer in the direction of the stage 18 than the probe 14. Further, the resistance measuring probe 60 can be detached from the probe card 12. The stage resistance value is acquired by applying the resistance measurement probe 60 to the upper surface 18 a of the stage 18 and passing a current between the resistance measurement probe 60 and the connection portion 22. When acquiring the electrical characteristics of the semiconductor device, the resistance measurement probe 60 is removed from the probe card 12 and the probe 14 is applied to the upper surface of the semiconductor device.

  By using the resistance measurement probe 60 when measuring the stage resistance value and using the probe 14 when measuring the semiconductor device, the resistance measurement probe 60 can be optimized to measure the stage resistance value. The probe 14 can be optimized for measuring semiconductor devices. For example, the probe 14 can be shaped to have a pointed tip while the tip of the resistance measuring probe 60 can be brought into surface contact with the stage 18. Further, the resistance measurement probe 60 is formed of a hard material so as not to be deformed by contact with the stage 18, and the probe 14 is formed of a relatively soft material to prevent damage to the semiconductor device. Further, since it is not necessary to apply the probe 14 to the stage 18, the life of the probe 14 can be extended.

  In the second embodiment of the present invention, the resistance measurement probe 60 is removable from the probe card 12, but the resistance measurement probe 60 may be foldable, for example. In this case, when acquiring the electrical characteristics of the semiconductor device, the resistance measurement probe 60 is folded and the probe 14 is applied to the upper surface of the semiconductor device. In addition, the semiconductor device can be modified at least as much as the semiconductor device measurement method and the measurement device according to the first embodiment.

Embodiment 3 FIG.
Since the semiconductor device measuring method and measuring instrument according to the third embodiment of the present invention have much in common with the first embodiment, the differences from the first embodiment will be mainly described. FIG. 8 is a diagram showing a measuring instrument according to Embodiment 3 of the present invention. A terminal 70 a is attached to the side surface of the stage 18. The measuring instrument according to Embodiment 3 of the present invention is characterized in that the stage resistance value is measured using a terminal attached to the stage 18.

  FIG. 9 is a plan view of FIG. Terminals 70 a, 70 b and 70 c are attached to the side surface of the stage 18. The terminals 70a, 70b, and 70c are electrically connected to the evaluation unit 28 by signal lines. When the semiconductor device 20 is divided into the first region 20a, the second region 20b, and the third region 20c as shown by a broken line in FIG. 9, the terminal 70a is positioned in the vicinity of the first region 20a, and the terminal 70b is the second region. The terminal 70c is located in the vicinity of the third region 20c.

  A method for determining the stage resistance value will be described. First, a resistance value between the terminal 70a and the connection portion 22 (referred to as a first resistance value), a resistance value between the terminal 70b and the connection portion 22 (referred to as a second resistance value), and between the terminal 70c and the connection portion 22 A resistance value (referred to as a third resistance value) is measured.

  The first resistance value is used as a stage resistance value for a measurement result obtained by applying a probe to the first region 20 a of the semiconductor device 20. The second resistance value is used as a stage resistance value for a measurement result obtained by applying a probe to the second region 20b of the semiconductor device 20. The third resistance value is used as a stage resistance value for a measurement result obtained by applying a probe to the third region 20 c of the semiconductor device 20. As described above, the resistance value acquired by flowing a current between the terminals 70a, 70b, 70c attached to the stage 18 and the connection portion 22 is used as the stage resistance value. The calculation of the corrected measurement result in this way is called “division calculation”.

  According to the measuring instrument and the semiconductor device measurement method according to the third embodiment of the present invention, the semiconductor device is measured when measuring the electrical characteristics of the semiconductor device by using the terminals 70a, 70b, and 70c attached to the side surface of the stage 18. The stage resistance value can be measured in a state where is installed on the stage. Therefore, the measurement can be performed in a short time while simplifying the process as compared with the measurement method of the semiconductor device of the first embodiment.

  The method for determining the stage resistance value is not limited to the method described above. The above-described division calculation is preferably used when the first to third resistance values vary (for example, when the maximum value is twice or more the minimum value). When the stage resistance value varies depending on the stage position, a highly accurate corrected measurement result can be obtained by increasing the number of terminals and subdividing the region of the semiconductor device.

  On the other hand, when the variation of the first to third resistance values is small, for example, a value obtained by averaging three measured resistance values may be used as the stage resistance value in order to simplify the processing.

  The attachment positions of the terminals 70a, 70b, and 70c are not limited to the side surfaces of the stage 18. For example, you may attach to the upper surface 18a of the stage 18 so that it may not contact with a semiconductor device. In addition, the semiconductor device can be modified at least as much as the semiconductor device measurement method and the measurement device according to the first embodiment.

Embodiment 4 FIG.
Since the semiconductor device measuring method and measuring instrument according to the fourth embodiment of the present invention have much in common with the first embodiment, the differences from the first embodiment will be mainly described. FIG. 10 is a diagram showing a measuring instrument according to Embodiment 4 of the present invention. A temperature sensor 80 is attached to the side surface of the stage 18. The measuring instrument according to Embodiment 4 of the present invention is characterized in that the stage resistance value is corrected using the temperature of the stage 18 obtained by the temperature sensor 80.

  FIG. 11 is a plan view of the stage of FIG. 10 and its periphery. The temperature sensor 80 is attached at a position where the temperature of the side surface of the stage 18 can be measured. Hereinafter, a method for measuring a semiconductor device according to the fourth embodiment of the present invention will be described. FIG. 12 is a flowchart showing a semiconductor device measurement method according to the fourth embodiment of the present invention. First, the stage resistance value is measured when the stage 18 is at the first temperature. Further, the temperature of the first temperature stage is measured by the temperature sensor 80 (step 90). Then, the stage resistance value, the coordinate information obtained from the stage resistance value, and the first temperature information measured by the temperature sensor 80 are stored in the storage unit 28a. Note that the first temperature is, for example, room temperature.

  Next, a measurement result (measurement result of electrical characteristics of the semiconductor device) is acquired in a state where the stage 18 is heated or cooled to set the stage 18 to a second temperature different from the first temperature. Further, the temperature of the second temperature stage is measured by the temperature sensor 80 (step 92). The measurement result is transmitted to the evaluation unit 28 together with information on the coordinates of the place where the measurement result is obtained and information on the second temperature measured by the temperature sensor 80.

  Next, the evaluation unit 28 calculates a change in the stage resistance value when the temperature of the stage 18 is changed from the first temperature to the second temperature. This change may be obtained by calculation, or may be obtained by referring to a table stored in advance in the storage unit 28a of the evaluation unit 28. The table shows, for example, “a change in resistance value with respect to temperature” before the stage 18 is deteriorated with time.

Next, the evaluation unit 28 generates a stage resistance value obtained by adding this change to the stage resistance value acquired in Step 90 (Step 94). Specifically, it is calculated by the following formula 2.
Stage resistance value = stage resistance value at the first temperature + change amount.
This stage resistance value is generated for each place where the measurement result is obtained. Next, a corrected measurement result is calculated using the stage resistance value generated in step 94 (step 96).

  According to the semiconductor device measurement method and the measuring instrument according to the fourth embodiment of the present invention, when the semiconductor device is measured at a high temperature or a low temperature, the measurement result can be corrected by the stage resistance value reflecting the temperature at the time of the measurement. . Therefore, it is possible to obtain a corrected measurement result in which the influence of the stage resistance value is excluded from the measurement result obtained at a high temperature or a low temperature. Note that the semiconductor device measuring method and measuring instrument according to the fourth embodiment of the present invention can be modified at least as much as the semiconductor device measuring method and measuring instrument according to the first embodiment.

  DESCRIPTION OF SYMBOLS 10 Measuring instrument, 12 Probe card, 14 Probe, 16 Probe card connection part, 18 Stage, 18a Upper surface, 18b Groove, 18c Suction port, 20 Semiconductor device, 20a 1st area | region, 20b 2nd area | region, 20c 3rd area | region, 22 Connection unit, 24 stage resistance, 26 signal line, 28 evaluation unit, 28a storage unit, 28b measurement unit, 28c calculation unit, 28d output unit, 30 signal line, 50 arm, 60 resistance measurement probe, 70a, 70b, 70c terminal 80 Temperature sensor

Claims (10)

Obtaining a stage resistance value which is a resistance value from a predetermined position on the upper surface of the stage to a connection portion attached to the stage, and transmitting the stage resistance value to the evaluation unit;
Contacting the back surface of the semiconductor device with the top surface of the stage, and applying a probe to the top surface of the semiconductor device;
The evaluation unit obtains a measurement result of the semiconductor device by passing a current through a path from the probe to the evaluation unit via the semiconductor device, the stage, and the connection unit;
And a step of calculating a modified measurement result obtained by correcting the measurement result so that the evaluation unit eliminates the influence of the stage resistance value on the measurement result.   The method of measuring a semiconductor device according to claim 1, wherein a position where the probe is applied to an upper surface of the semiconductor device is immediately above the predetermined position. A plurality of the stage resistance values are obtained at different positions on the upper surface of the stage,
A plurality of the measurement results are obtained at different positions on the upper surface of the stage,
2. The method of measuring a semiconductor device according to claim 1, wherein the calculation of the corrected measurement result is performed using the stage resistance value at a position on the stage where the measurement result is obtained.   4. The semiconductor device according to claim 1, wherein the stage resistance value is acquired by applying the probe to the stage and passing a current between the probe and the connection portion. 5. Measuring method.   The stage resistance value is obtained by applying a resistance measurement probe to the stage and passing a current between the resistance measurement probe and the connection portion. A method for measuring a semiconductor device according to claim 1.   The method of measuring a semiconductor device according to claim 1, wherein the stage resistance value is obtained by passing a current between a terminal attached to the stage and the connection portion. The stage resistance value is measured when the stage is at the first temperature,
The measurement result is obtained in a state where the stage is set to a second temperature different from the first temperature,
The evaluation unit generates a stage resistance value in which a change amount of the stage resistance value when the temperature of the stage is changed from the first temperature to the second temperature is added to the stage resistance value. The method for measuring a semiconductor device according to claim 1. A probe fixed to a probe card;
A stage formed of a conductive material;
A connecting portion attached to the stage;
An evaluation unit that is connected to the probe and the connection unit and obtains a stage resistance value that is a resistance value from a predetermined position on the upper surface of the stage to the connection unit;
The evaluation unit measures the measurement results obtained by passing a current from the probe through a path passing through the semiconductor device, the stage, and the connection unit placed on the upper surface of the stage, and determines the influence of the stage resistance value. A measuring instrument characterized by being modified to eliminate. Comprising a resistance measuring probe attached to the probe card;
The tip of the resistance measurement probe has a shape capable of surface contact with the stage,
The measuring instrument according to claim 8, wherein the resistance measuring probe is removable or foldable from the probe card. A terminal attached to the stage;
A signal line connecting the terminal and the evaluation unit,
The measuring device according to claim 8, wherein the evaluation unit acquires the stage resistance value by passing a current between the terminal and the connection unit.

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