JP2008096129A - Apparatus for measuring potential gradient, and electronic device process evaluating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability in evaluating the electric charge of electronic device processes, by setting the threshold of potential gradient, in consideration of the electrostatic resistance of devices themselves and their scale in a potential gradient measuring apparatus and an electronic device process evaluating apparatus. <P>SOLUTION: The apparatus for measuring potential gradient is provided with a potential measuring means 2 for measuring the potential of a plurality of locations in an object to be measured 1; a potential distribution detection means for determining a potential distribution, on the basis of detection signals of the potential measuring means 2; and a potential gradient computing means 4 for computing potential gradient, on the basis of detection signals of the potential measuring means 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a potential gradient measuring apparatus and an electronic device process evaluation apparatus, and in particular, electrostatic charging by a process apparatus used in a manufacturing process of an electronic device such as a thin film magnetic head or a semiconductor integrated circuit device is performed according to the characteristics of the electronic device. The present invention relates to a potential gradient measuring apparatus and an electronic device process evaluation apparatus characterized by a configuration for evaluation.

  Electronic devices such as thin film magnetic heads and semiconductor integrated circuit devices are becoming more and more miniaturized year by year, and their static electricity resistance is further reduced. Therefore, static electricity management is important in the manufacturing process of electronic devices.

  For example, in a manufacturing process involving charged particles, such as a plasma processing process such as plasma etching or plasma CVD in a manufacturing process of a semiconductor integrated circuit device, an ion implantation process, or an ion milling process when patterning an upper magnetic pole of a thin film magnetic head. It is known that charges are accumulated on the surface of the processing substrate.

  The charge accumulation state on the surface of the processing substrate differs depending on the individual process apparatus, and also depends on the adjustment state of the individual process apparatus. It is necessary to grasp the charge accumulation state on the entire surface of the substrate.

  As a technique for measuring the electrostatic charge state in the electronic device manufacturing process, it is known to measure the capacitance between the electrode of the potential sensor and the substrate on which the electronic device is provided in a non-contact manner through an air gap. (For example, refer to Patent Document 1).

  In addition, using a potential sensor in which potential sensor elements are arranged in an array, the potential on the surface of the measurement target substrate is quickly measured without contact, the potential is determined with a predetermined threshold, and the distribution is displayed as a map. It has also been proposed to do.

See FIG.
FIG. 8 is an explanatory diagram of an example of a conventional potential measuring method. The scanning target 42 is used to relatively scan the measurement target substrate 41 and the potential sensor array 43, and a large number of measurements on the surface of the measurement target substrate 41 are performed. A display in which the electrostatic potential level at a point is measured, the measured electrostatic potential level is A / D-changed by the potential signal processing means 44, and the potential distribution for each measurement point subjected to A / D conversion is provided in the potential distribution display / recording means 45. And the like are mapped or recorded (for example, see Patent Document 2).

See FIG.
FIG. 9 shows the measured potential profile, and here, the measurement result for one line of the wafer is shown as a model.

Such potential measurement can be performed almost in real time if a potential sensor can be installed in the manufacturing process.
On the other hand, when the potential sensor cannot be installed in the manufacturing process, the object to be measured is put into the manufacturing process apparatus, and the surface potential is measured after a predetermined process.
In this case, the state of the manufacturing process is evaluated by evaluating the charged potential of the object to be measured.

When such a method is applied to a wafer on which a large number of minute devices are formed, the potential distribution on the wafer surface and the local potential can be evaluated.
JP 11-337602 A JP 07-072196

  On the other hand, when attention is paid to individual devices on a wafer, an electronic device is generally evaluated by an electrostatic resistance (destructive) test as to electrostatic resistance of the device itself as part of static electricity management.

  For example, as an example of an electrostatic resistance test, a method of applying an electrostatic discharge model waveform such as a human body model, a machine model, a device charging model, or a rectangular pulse waveform as a stress signal is known.

See FIG.
FIG. 10 is an explanatory diagram of the electrostatic withstand voltage of the electronic device formed on the wafer.
In general, a plurality of electrodes are connected to the electronic device. However, in order to simplify the description, the two electrodes 53 and 54 are arranged at a minute interval L [mm] of 2 to 5 mm with respect to the size of the entire wafer 51. It is assumed that the device 52 is connected.

In the above-described electrostatic test, as a result of a test in which a plurality of levels of potential difference E [V] are applied between the two electrodes 53 and 54, it is found that the device resistance is E _s [V].
In this case, the potential gradient ΔE _s of E _s / L [V / mm] can be considered as the electrostatic resistance of the device in a minute region with electrodes.

  Incidentally, the wafer forming the magnetic disk head is devised in the element structure and material for discharging so that the charge accumulated on the wafer surface does not damage the element even if there is a factor to be charged in the process apparatus. However, the state of the manufacturing process may not always be stable, and the element may be destroyed by charging in the process apparatus, so the above-described electrostatic test is necessary.

  However, in the above-described conventional technology, as shown in FIG. 9, there is no concept of a potential gradient even though the potential on the wafer surface can be known, so that it cannot be evaluated in relation to the electrostatic resistance of each device. was there.

  Therefore, an object of the present invention is to improve the reliability of charging evaluation of an electronic device process by setting a threshold value of a potential gradient in consideration of electrostatic resistance of the device itself and its scale.

FIG. 1 is a block diagram showing the principle of the present invention, and means for solving the problems in the present invention will be described with reference to FIG.
Incidentally, reference numeral 3 in the figure denotes a potential signal processing means.
Refer to FIG. 1 In order to solve the above-mentioned problem, the present invention is a potential gradient measuring apparatus, which measures potentials at a plurality of locations of a measurement object 1, and detects potentials based on detection signals from the potential measuring means 2. It is characterized by having a potential distribution detecting means for obtaining a distribution and a potential gradient calculating means 4 for calculating a potential gradient based on a detection signal of the potential measuring means 2.

  Thus, in addition to the potential measuring means 2 for measuring the potential at a plurality of locations of the measurement object 1 provided in the conventional potential gradient measuring apparatus, the potential distribution detecting means for obtaining the potential distribution by the detection signal of the potential measuring means 2. And by providing the potential gradient calculation means 4 for calculating the potential gradient based on the detection signal of the potential measurement means 2, the surface potential state of the measurement object 1 and the electrostatic resistance of each device can be evaluated.

  In this case, the potential gradient calculation unit 4 may use the detection signal output of the potential measurement unit 2 to obtain a differential output by numerical calculation, and the potential without changing the measurement system of the conventional potential gradient measurement device. The slope can be determined.

  Such a potential measuring means 2 is typically a potential sensor element array in which potential sensors are arranged in a one-dimensional array.

  Further, the potential measuring means 2 is composed of a potential sensor block made up of a plurality of potential sensor elements, so that the potential gradient calculating means 4 outputs two detection signal outputs selected from the plurality of potential sensor elements. By calculating the difference in the difference circuit and outputting it, the electronic gradient at an arbitrary position can be quickly obtained.

  Further, it is desirable to have a means for selecting a region for measuring the potential gradient based on the spatial arrangement information of the electronic device formed on the measurement object 1, and based on the two-dimensional shape or three-dimensional shape of the electronic device. An arbitrary region can be selectively measured.

  The potential gradient measuring device preferably includes a recording means for recording the potential distribution and the potential gradient and a display means for displaying the recording means, thereby extracting the potential distribution and the potential gradient as visual information at an arbitrary time. be able to.

  An electronic device process evaluation apparatus can be configured by adding abnormality determining means for determining process abnormality from the measured potential gradient to the above-described potential gradient measuring apparatus.

  In this case, when the abnormality determination threshold value of the potential gradient in the abnormality determination unit is E, the withstand voltage of the electronic device formed on the abnormality determination object 1 is E, and the distance between the electrodes connected to the electronic device is L, E / What is necessary is just to set to L.

  Further, when performing an electronic device process evaluation, the potential gradient is measured using the above-described potential gradient measuring apparatus as a measurement target 1 with a dummy substrate serving as a dummy of the abnormality determination target 1, and based on the measurement result. What is necessary is just to judge process abnormality.

  In other words, the wafer that forms the actual device is devised in the element structure and material to discharge so that the charge accumulated on the wafer surface does not damage the element even if there is a factor to be charged in the process, Even if it is charged inside the process equipment, when it goes out of the process equipment, the charged charge is discharged so as not to destroy the device, and it is difficult to grasp the state of the process equipment from the actual wafer. It is necessary to use a substrate.

  According to the present invention, by automatically obtaining a potential gradient, it becomes possible to evaluate the effect of charging using a threshold value based on electrostatic resistance corresponding to the scale of the electronic device, and as a result, The reliability of static electricity management in the manufacturing process can be improved.

  The present invention measures the potential at a plurality of locations of the measurement object with the potential measuring means, calculates the potential distribution based on the detection signal of the potential measuring means, calculates the potential gradient, records the potential distribution and the potential gradient, This is displayed as required by the display means.

  Further, from the measured potential gradient, when the withstand voltage of the electronic device formed on the abnormality determination target object is E and the distance between the electrodes connected to the electronic device is L, E / L The process abnormality is determined based on the abnormality determination threshold set in (1).

Here, with reference to FIG. 2 thru | or FIG. 4, the electric potential gradient measuring apparatus of Example 1 of this invention is demonstrated. See FIG. 2 and FIG.
FIG. 2 is a conceptual configuration diagram of the potential gradient measuring apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic configuration diagram of a main part of the potential gradient measuring apparatus according to the first embodiment of the present invention. An electric potential sensor array 11 that measures the surface potential of the dummy wafer 10 that is an object in a non-contact manner, an XY stage 12 that places the dummy wafer and scans the electric potential sensor array 11, and an output E from the electric potential sensor array 11 potential signal processing means 13 processes the ₁ to E _n to a potential signal S ₁ to S _n, records the electric potential distribution on the surface of the dummy wafer 10 based on the potential signal S ₁ to S _n from the potential signal processing means 13 potential distribution display and recording means 14 to be displayed on the display as well as, potential gradient Starring for calculating the potential gradient of the surface of the dummy wafer 10 based on the potential signal S ₁ to S _n from the potential signal processing means 13 Means 15, the potential gradient calculating potential gradient signal ΔS _1,2 ~ΔS from means 15 _n-1, the potential gradient display and recording means for displaying on the display and records _n as potential gradient distribution of the surface of the dummy wafer 10 16 Consists of.

In this case, the pitch of each potential sensor 11 _i in the potential sensor array 11 is several mm, for example, 3 mm, and the potential sensor array 11 changes the potential in the array direction (for example, the X direction) to XY. Measurement is performed while the stage 12 is scanned in the Y direction.
When the length of the potential sensor array 11 is shorter than the diameter of the dummy wafer 10, the potential of the entire surface of the dummy wafer 10 is measured by scanning also in the X direction.

  Even if the wafer or the like forming the magnetic disk head can be gradually discharged even if it is charged, even if it is charged inside the process device, the charged charge will destroy the element when it is taken out of the process device. It is difficult to grasp the state of the process apparatus from the actual wafer.

  Therefore, together with the actual wafer forming the magnetic disk head element or individually, a dummy wafer 10 that does not easily release charged charges is put into the process apparatus, and the manufacturing process exerted on the actual wafer by the surface potential gradient of the dummy wafer 10 It indirectly evaluates the state of the device.

See Figure 4
FIG. 4 shows the measured potential gradient profile, and here, the measurement result for one line on the dummy wafer 10 is also shown as a model.
The potential gradient at each position is a plot of the above-described potential gradient signals ΔS _{1,2 to} ΔS _{n-1, n} .

Here, the threshold value relating to the determination of the quality of the potential gradient will be described.
In the manufacture of magnetic disk heads, a large number of fine elements are formed on a wafer. Therefore, a resistance test is performed on two or more elements of the same type via two electrodes, and the average level E is determined from the resistance of the plurality of elements. Ask.
Generally, static resistance is stable at an equivalent level if the elements are of the same type.

Here, when the surface of the dummy wafer 10 is associated with the measured potential gradient, if the potential difference generated between the electrodes L [mm] connected to the element exceeds the withstand voltage E [V] in the manufacturing process apparatus, the element is destroyed. Considering this, the potential gradient in this case is E / L [V / mm]. Therefore, the potential gradient ΔE _{s at which} element destruction occurs is
ΔE _s = E / L [V / mm]
It becomes.

Therefore, in FIG. 4, ± ΔE _s [V / mm] is set as the potential gradient threshold when setting the threshold value as the danger level in the potential gradient data.

  As described above, in the first embodiment of the present invention, since the potential gradient calculation means is provided, the potential gradient distribution can be automatically acquired from the measured potential distribution without manual operation. By displaying the distribution by the potential gradient display / recording means, the potential gradient can be quickly grasped as long as it leads to an element defect.

Here, with reference to FIG. 5, the electronic device process evaluation apparatus of Example 2 of this invention is demonstrated.
See Figure 5
FIG. 5 is a conceptual configuration diagram of an electronic device process evaluation apparatus according to Embodiment 2 of the present invention, in which a potential gradient determination unit is incorporated in the potential gradient measurement apparatus according to Embodiment 1 described above.

In other words, this electronic device process evaluation apparatus has a potential sensor array 11 for measuring the surface potential of the dummy wafer 10 as a measurement object in a non-contact manner, a dummy wafer placed thereon, and an X− that scans the potential sensor array 11. Y stage 12, the potential signal processing means 13 for the potential signal S ₁ to S _n processes the output E ₁ to E _n from the potential sensor array 11, the potential signal S ₁ to S _n from the potential signal processing means 13 potential distribution display and recording means 14 to be displayed on the display records the potential distribution of the surface of the dummy wafer 10 on the basis of the surface of the dummy wafer 10 based on the potential signal S ₁ to S _n from the potential signal processing means 13 potential gradient calculating means 15 for calculating a potential gradient, the surface of the potential gradient signal ΔS _1,2 ~ΔS _n-1, n dummy wafers 10 from the potential gradient calculating means 15 Potential gradient display and recording unit 16 on a display and records as potential gradient distribution and the potential gradient signal from the potential gradient calculating means _{15 ΔS 1,2 ~ΔS n-1,} n the potential gradient threshold voltage ± E Compared with _s, it comprises a potential gradient judging means 17 for judging a process abnormality and notifying the potential gradient display / recording means 16 of the occurrence of the process abnormality.

  As described above, in the second embodiment of the present invention, since the potential gradient determining means 17 is provided, a process in which element breakdown may occur just by measuring the surface potential of the dummy wafer 10 with the potential sensor array 11. Abnormalities can be detected automatically.

Here, with reference to FIG. 6, the electric potential gradient measuring apparatus of Example 3 of this invention is demonstrated.
See FIG.
FIG. 6 is a schematic configuration diagram of a main part of the potential gradient measuring apparatus according to the third embodiment of the present invention, in which a potential sensor pair 21 that measures the surface potential of the dummy wafer 10 as a measurement object in a non-contact manner, and the dummy wafer 10 and an X-Y stage 22 that scans the potential sensor pair 21 in the X and Y directions, and outputs E _{1i and} E _2i from the potential sensor pair 21 (the suffix i is i on the dummy wafer 10). (Meaning data at the second position) to be processed into potential signals S _1i and S _2i , and a difference for calculating a difference ΔS _i between the electronic signals S _1i and S _2i from the potential signal processing means 23. The calculation means 24 includes a potential gradient calculation means 25 for calculating a potential gradient ΔS _i / L from the potential difference signal ΔS _i .
The difference calculation means may be a hardware difference calculation circuit or a software calculation processing means.

In this case, the pitch between the two potential sensors 21 ₁ and 21 ₂ constituting the potential sensor pair 21 is set to a distance L [mm] to be evaluated, for example, a distance between electrodes, and specifically, several mm. For example, it is 3 mm, and the potential of the surface of the dummy wafer 10 is measured by the potential sensor pair 21 while the dummy wafer 10 is scanned in the XY direction by the XY stage 12.

  In this case, the potential of the entire surface of the dummy wafer 10 may be measured by the potential sensor pair 21, or only a specific portion is measured based on the two-dimensional shape information or the three-dimensional shape information of the dummy wafer 10. For example, it is efficient to select only a region where an element and an electrode to be evaluated are arranged.

Although not shown, this case also includes a potential distribution display / recording unit and a potential gradient display / recording unit. When an electronic device process evaluation apparatus is configured, a potential gradient signal ΔS is provided. _What is necessary is to provide a potential gradient determining means for comparing the _i / L with the potential gradient threshold voltage ± E _s to determine the process abnormality and notifying the potential gradient display / recording means of the occurrence of the process abnormality.

Here, with reference to FIG. 7, the electric potential gradient measuring apparatus of Example 4 of this invention is demonstrated.
See FIG.
FIG. 7 is a schematic configuration diagram of a main part of a potential gradient measuring apparatus according to a fourth embodiment of the present invention, in which a potential sensor block 31 that measures the surface potential of a dummy wafer 10 as a measurement object in a non-contact manner, and a dummy wafer 10 and an XY stage 32 that scans the potential sensor block 31 in the X and Y directions, and processes the outputs from the potential sensor block 31 to process potential signals S _i and S _j (i = 1 to 4). , j = 1 to 4, the potential signal processing means 33 to i ≠ j), the potential signal S _i from the potential signal processing means 33, two specific potential signals S _i of the S _j, is S _j are input The difference calculating means 34 for calculating the difference ΔS _ij and the potential gradient calculating means 35 for calculating the potential gradient ΔS _ij / L from the potential difference signal ΔS _ij .
In this case, the difference calculation means may be a hardware difference calculation circuit or a software calculation processing means.

In this case, a plurality of potential sensors potential sensor block 31 arranged one-dimensionally, here, consists of four potential sensor 31 _{1-31 4,} the pitch, several mm, for example, a 3 mm, the potential sensor block 31, the potential of the surface of the dummy wafer 10 is measured while the dummy wafer 10 is scanned in the XY direction by the XY stage 32.

  In this case, the potential of the entire surface of the dummy wafer 10 may be measured by the potential sensor block 31, or only a specific portion is measured based on the two-dimensional shape information or the three-dimensional shape information of the dummy wafer 10. For example, it is efficient to select only a region where an element and an electrode to be evaluated are arranged.

In Example 4, the potential signals S _{1 to} S ₄ from the plurality of potential sensors 31 _{1 to} 31 ₄ are to be evaluated, and the distance according to the size of the device and therefore the distance between the two electrodes. Since the difference ΔS _ij between the potential signals S _i and S _j (i = 1 to 4, j = 1 to 4, i ≠ j) of the two specific potential sensors arranged in FIG. It can be shortened.

Although not shown, this case also includes a potential distribution display / recording unit and a potential gradient display / recording unit. When an electronic device process evaluation apparatus is configured, a potential gradient signal ΔS is provided. _What is necessary is to provide a potential gradient determining means for comparing _ij / L with the potential gradient threshold voltage ± E _s to determine a process abnormality and to notify the potential gradient display / recording means of the occurrence of the process abnormality.

  As mentioned above, although each Example of this invention was described, this invention is not restricted to the structure, conditions, and numerical value which were shown in each Example, A various change is required, for example in said Example 1 Finds a gradient that is calculated one-dimensionally in the X direction in a line, but two-dimensional calculation including the Y direction may be performed.

  In addition, when the dummy wafer 10 has a specific three-dimensional structure, it is necessary to measure with a constant interval between the dummy wafer and the potential sensor. , And measurement is performed while controlling the position of the potential sensor in the Z direction based on the three-dimensional shape information, thereby enabling highly accurate measurement.

Here, referring to FIG. 1 again, the detailed features of the present invention will be described again.
Again see Figure 1
(Additional remark 1) By the electric potential measurement means 2 which measures the electric potential of several places of the measuring object 1, the electric potential distribution detection means which calculates | requires electric potential distribution by the detection signal of the said electric potential measurement means 2, and the detection signal of the said electric potential measurement means 2 A potential gradient measuring device having a potential gradient calculating means 4 for calculating a potential gradient.
(Supplementary note 2) The potential gradient measuring device according to supplementary note 1, wherein the potential gradient calculating means 4 uses the detection signal output of the potential measuring means 2 to obtain a differential output by numerical calculation.
(Supplementary note 3) The potential gradient measuring device according to supplementary note 1 or 2, wherein the potential measuring means 2 is composed of a potential sensor element array arranged in a one-dimensional array.
(Supplementary Note 4) The potential measuring means 2 includes a potential sensor block including a plurality of potential sensor elements. In the potential gradient calculating means 4, two detection signals selected from the plurality of potential sensor elements. 3. The potential gradient measuring device according to appendix 1 or 2, wherein the output is subjected to a difference calculation by a difference circuit and output.
(Additional remark 5) It has a means to select the area | region which measures an electric potential gradient based on the spatial arrangement information of the electronic device formed in the said measurement object 1, Any one of Additional remark 1 thru | or 4 characterized by the above-mentioned. Potential gradient measuring device.
(Supplementary Note 6) A recording unit that records the potential distribution detected by the potential distribution detection unit and the potential gradient detected by the potential gradient calculation unit 4 and a display unit that displays the potential distribution and the potential gradient are provided. The electronic gradient measuring apparatus according to any one of appendices 1 to 5, which is characterized in that
(Appendix 7) An electronic device process comprising: the potential gradient measuring device according to any one of appendices 1 to 6; and an abnormality determining unit that determines a process abnormality from the potential gradient measured by the potential gradient measuring device. Evaluation device.
(Supplementary Note 8) When the abnormality determination threshold value of the potential gradient in the abnormality determination means is E, the withstand voltage of the electronic device formed on the abnormality determination object is E, and the distance between the electrodes connected to the electronic device is L The electronic device process evaluation apparatus according to appendix 7, wherein E / L is set.
(Supplementary Note 9) Using the potential gradient measuring device according to any one of Supplementary Notes 1 to 6, a potential gradient is measured using the dummy substrate serving as a dummy of the abnormality determination target as the measurement target 1, and based on the measurement result. An electronic device process evaluation method characterized by determining process abnormality.

  As a practical example of the present invention, the thin film magnetic head is typically applied to a process evaluation associated with a plasma processing step or an ion processing step of a wafer or a semiconductor wafer on which a thin film magnetic head is formed. However, the present invention is applied to process evaluations associated with plasma processing steps and ion processing steps of various electronic devices such as ferroelectric devices and superconducting devices.

It is explanatory drawing of the fundamental structure of this invention. It is a notional block diagram of the electric potential gradient measuring apparatus of Example 1 of this invention. It is a principal part schematic block diagram of the electric potential gradient measuring apparatus of Example 1 of this invention. It is the measured electric potential gradient profile. It is a notional block diagram of the electronic device process evaluation apparatus of Example 2 of this invention. It is a principal part schematic block diagram of the electric potential gradient measuring apparatus apparatus of Example 3 of this invention. It is a principal part schematic block diagram of the electric potential gradient measuring apparatus apparatus of Example 4 of this invention. It is explanatory drawing of an example of the conventional electric potential measurement method. This is a measured potential profile. It is explanatory drawing of the electrostatic withstand voltage of the electronic device formed on the wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement object 2 Potential measurement means 3 Potential signal processing means 4 Potential gradient calculation means 10 Dummy wafer 11 Potential sensor array 11 _i Potential sensor 12 XY stage 13 Potential signal processing means 14 Potential distribution display / recording means 15 Potential gradient calculation Means 16 Potential gradient display / recording means 17 Potential gradient determination means 21 Potential sensor pair 21 ₁ , 21 ₂ Potential sensor 22 XY stage 23 Potential signal processing means 24 Difference computing means 25 Potential gradient computing means 31 Potential sensor block 32 X− Y stage 33 Potential signal processing means 34 Difference calculating means 35 Potential gradient calculating means 31 _{1 to} 31 ₄ Potential sensor 41 Measurement target substrate 42 Scanning means 43 Potential sensor array 44 Potential signal processing means 45 Potential distribution display / recording means 51 Wafer 52 Device 53 electrode 54 electrode

Claims (5)

Potential measuring means for measuring the potential at a plurality of locations of the measurement object, potential distribution detecting means for obtaining a potential distribution from the detection signal of the potential measuring means, and potential gradient calculation for calculating a potential gradient based on the detection signal of the potential measuring means A potential gradient measuring device comprising means. 2. The potential gradient measuring device according to claim 1, wherein the potential gradient calculating means obtains a differential output by numerical calculation using the detection signal output of the potential measuring means. The potential measuring means comprises a potential sensor block made up of a plurality of potential sensor elements. In the potential gradient calculating means, the difference detection circuit outputs a difference between two detection signal outputs selected from the plurality of potential sensor elements. The potential gradient measuring device according to claim 1 or 2, wherein the potential gradient is calculated and output. The potential gradient according to any one of claims 1 to 3, further comprising means for selecting a region for measuring a potential gradient based on spatial arrangement information of an electronic device formed on the measurement object. measuring device. 5. An electronic device process evaluation apparatus comprising: the potential gradient measuring apparatus according to claim 1; and an abnormality determination unit that determines process abnormality from the potential gradient measured by the potential gradient measuring apparatus. .

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