JP2000114327A - Resistivity measuring instrument for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an automatic resistivity measuring instrument for semiconductor wafers using a four-point probe, to accurately measure the resistivity of a large diameter wafer to a point near the peripheral edge by improving the accuracy of lowering and positioning the four-point probe to a designated measuring point on the wafer. SOLUTION: The accuracy of lowering and positioning a four-point probe 2 of a resistivity measuring instrument to a designated point on a wafer 1 to be measured placed on a measuring stage 3 directly from a cassette is improved by detecting the eccentricity of the wafer 1, by means of a wafer eccentricity detecting sensor 10 utilizing a laser beam after the wafer 1 is turned by one round by means of a rotational drive section 4, and then correcting and controlling the lowering and contacting position of the probe 2 to the designated point by using the information about the eccentricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the resistivity of a semiconductor wafer relating to a semiconductor manufacturing apparatus.
The present invention relates to a resistivity measuring device using a four-point probe method.

[0002]

2. Description of the Related Art An apparatus for measuring the resistivity of a semiconductor wafer includes the resistivity of a silicon wafer, the resistivity of an epitaxially grown film formed on the wafer surface, and the sheet resistance and the surface of a diffusion layer when impurities are diffused or implanted from the surface. This is a device that measures the sheet resistance of the generated metal film and the like, and the measurement result is fed back to the process conditions of each semiconductor manufacturing device, and is one of the important measuring devices for keeping the quality of the semiconductor device uniform.

FIG. 6 is a plan view of a semiconductor wafer. G
An aAs wafer or Si wafer is provided with an orientation flat (usually abbreviated as OF or orientation flat) or a notch (notch) indicating a crystallographic reference direction. This orientation flat or notch
After the outer diameter grinding of the single crystal ingot, before slicing, the ingot is formed in a predetermined crystal orientation on the side surface of the ingot by a predetermined width processing or groove processing. Small wafer size, for example, 3 inches in diameter, 100-150m
The m flat wafer is provided with an orientation flat, and a large size, for example, a 200 mm wafer is provided with an orientation flat or a notch, and the 300 mm wafer is provided with a notch. The direction of the center or notch of the orientation flat from the center of the wafer is referred to as the reference direction of the wafer.

FIG. 7 is a principle diagram of resistivity measurement by the DC four probe method. For measuring the resistivity, which is one of the evaluations of the semiconductor wafer, the DC four probe method is most widely used.
In the figure, reference numeral 1 denotes a semiconductor wafer (hereinafter, referred to as a wafer), and reference numeral 2 denotes a four-probe probe in which four probes are arranged at equal intervals (s). In the direct current four-probe method, a four-probe probe 2 is brought into contact with the surface of a wafer 1 at a predetermined pressure, a direct current I is applied to two of the two ends, and a voltage V between the two probes is measured. This is a method of calculating the resistivity ρ [Ω · cm] by the following equation.

Ρ = 2πs (V / I) · Fw · Fr [Ω · cm] where Fw: correction term based on wafer thickness w Fr: correction term based on wafer diameter (2r) and measurement position

FIG. 8 is an explanatory view showing an outline of a conventional semiconductor wafer automatic resistivity measuring apparatus. In the figure, reference numeral 1 denotes a wafer to be measured, and reference numeral 20 denotes a wafer cassette containing the wafer 1. 21 is the deviation of the center of the wafer,
A device (commonly referred to as an orientation flat aligning machine) for detecting the deviation of the orientation of the orientation flat or the notch direction from the measurement reference direction and aligning the center and the angle of the wafer in a correct measurement state, 22 is a wafer chuck stage, 23 is a wafer edge. It is a sensor. Reference numeral 24 denotes a wafer transfer robot (automatic transfer machine). Reference numeral 25 denotes a semiconductor wafer resistivity measurement device, reference numeral 2 denotes a 4-probe probe, and reference numeral 3 denotes a measurement stage. This resistivity measuring device aligns the center of the wafer 1 to be measured with the orientation flat or the notch direction (angle) with the orientation flat aligner 21 and then places the center on the measurement stage 3 of the resistivity measurement device 25. The angle is correctly set to the measurement reference position and the object is placed.

An outline of this operation will be described with reference to FIG. (1) The wafer 1 in the wafer cassette 20 is transferred and placed on the chuck stage 22 of the orientation flat aligner 21 by the wafer transfer robot 24. (2) The orientation flat aligner 21 includes a chuck stage 22
The upper wafer 1 is rotated, and the edge sensor 23 is used to measure the position of the peripheral edge of the wafer 1 at regular angles over the entire circumference of the wafer. As a result, the deviation of the direction (angle θ) of the orientation flat position or the notch position, the X direction of the center,
The amount of deviation in the Y direction is calculated. Then, based on the obtained amount of deviation, the angle θ and the position of each of the X and Y axes are correctly adjusted so that the wafer 1 comes to a predetermined position. That is, the positioning of the wafer 1 is performed. (3) Next, the correctly aligned wafer 1 is transferred from the chuck stage 22 to the resistivity measuring device 25 by the transfer robot 24 and placed on the measurement stage 3. At this time, the teaching position of the transfer robot 24 is accurately adjusted so that the wafer 1 is accurately aligned with the center of the measurement stage 3 and the angle reference position. (4) The resistivity measuring device 25 moves the four-probe probe 2 toward the center of the measurement stage 3 and rotates the measurement stage 3 to correctly align the probe 2 with the position of the specified measurement point on the wafer. Then, contact the wafer and measure the resistivity at that point. (5) The resistivity measuring device 25 sequentially measures a large number of designated measuring points on the wafer, and outputs the result by printing or the like,
When the measurement of the wafer is completed, the transfer robot 24 returns the wafer to the cassette 20. (6) The above items 1 to 5 are repeated, and the measurement of all wafers is completed.

FIGS. 9A and 9B are schematic views for explaining the structure of a conventional resistivity measuring device 25, wherein FIG. 9A is a plan view and FIG. 9B is a side view. FIG. 10 is a block diagram thereof.
In these figures, 1 is a wafer, 2 is a 4-probe probe, 3 is a measurement stage, 4 is a rotation drive unit of the measurement stage 3, 5 is a probe drive unit of the 4-probe probe 2, and 6 is a measurement unit (FIG. 9). In FIG. 7, reference numeral 7 denotes a control unit. 8
Although there are an operation unit, a display unit, a power supply unit, and the like, they are not shown in FIG.

[0008]

The specified range of measurement points on a single wafer is limited to 5 mm inside from the outer periphery of the wafer in a conventional semiconductor device manufacturing line. Was measured in the range in which was fabricated. However, recently, further miniaturization and higher yield are required, and devices have been manufactured as far as possible at the peripheral portion of the wafer, for example, at a portion 3 mm inside from the outer periphery. There has been a demand for a wider measurement area.

Therefore, in a resistivity measuring instrument using the four probe method, it has been required to accurately measure resistivity from 1 to 3 mm inside from the outer periphery of the wafer. Measurement of resistivity requires shape correction based on the position of the measurement point from the principle. In particular, since the distance from the outer periphery to the measurement point is short near the periphery of the wafer, there is a problem that the position accuracy of the measurement point greatly affects the measurement accuracy.

As a specific example, in a wafer having a diameter of 300 mmφ, even if the measurement position approaches 5 mm to 3 mm from the outer circumference, the measured value error of the resistivity relative to the measurement position error of ± 0.2 mm is about ± 0.15%. But 3m from outer circumference
As the distance from m to 2 mm to 1 mm approaches the outer circumference, the measured value error of the resistivity due to the position error increases rapidly. If the position error is ± 0.2 mm, the measured value cannot be practically used. For example, the measurement position is 2 m from the outer circumference
For points inside m, the peripheral correction coefficient is 0.974,
If there is a position error of ± 0.2 mm at the measurement position, the resistivity will be a measurement value error of about ± 1.0%. This is a very large value in practical use, and improvement in measurement accuracy is desired.

In order to increase the measurement accuracy, the accuracy of the measurement position must be increased. When the wafer is mounted on the measurement stage 3, the wafer is accurately positioned at a predetermined position (center and measurement reference angle) on the stage. Need to be placed in But,
In the above-described conventional apparatus, even when the wafer is accurately positioned by the expensive and accurate orientation flat aligner 21, even when the wafer is placed on the measurement stage 3 due to a transport error or a teaching error of the wafer transfer robot 24, It was extremely difficult to make the wafer position error of ± 0.2 mm or less.

The present invention has been made to solve the above-mentioned conventional problems, and has been made in consideration of the position (center and angle) of a wafer.
With the conventional method of accurately positioning the wafer and then placing it on the measurement stage, it is difficult to increase the position accuracy of the measurement points.Therefore, the wafer is directly placed on the measurement stage from the wafer cassette without aligning the wafer with the orientation flat aligner. It is an object of the present invention to provide a semiconductor wafer resistivity measuring instrument which measures a position of a wafer and minimizes a position error of a measurement point on the wafer so that an accurate resistivity can be measured up to the vicinity of a periphery of the wafer. Things.

[0013]

SUMMARY OF THE INVENTION A semiconductor wafer resistivity measuring instrument according to the present invention comprises a rotatable disk-shaped measuring stage on which a semiconductor wafer to be measured is mounted, a rotary drive for rotating the measuring stage, A four-probe probe for measuring resistivity by contacting a predetermined position on the upper surface of the semiconductor wafer mounted on the measurement stage, and moving the four-probe probe in the radial direction and the vertical direction of the measurement stage; A drive unit for moving the probe, an operation unit for designating and inputting the position of the resistivity measurement point on the upper surface of the semiconductor wafer, and the semiconductor driving the rotation drive unit and the probe drive unit according to the designation input inputted to the operation unit. At the designated position on the upper surface of the wafer,
In a semiconductor wafer resistivity measuring device provided with a control unit for measuring the resistivity by contacting the probe, provided near the periphery of the measurement stage, the periphery of the semiconductor wafer placed on the measurement stage Equipped with a wafer eccentricity detection sensor that measures the distance from the center of the measurement stage,
When the semiconductor wafer is mounted on the measurement stage, the control unit measures the distance from the center of the measurement stage around the periphery of the semiconductor wafer by the wafer eccentricity detection sensor over the entire circumference to measure the measurement reference position of the measurement stage. Detect the position error of the semiconductor wafer with respect to the, when operating the rotation drive unit and the probe drive unit at the position of the measurement point of the semiconductor wafer specified and input from the operation unit, calculated from the detected position error The resistance is measured by bringing the four-probe probe into contact with a position that takes into account the correction value.

Further, the measurement stage has a radius smaller than the radius of the semiconductor wafer to be mounted, and the wafer eccentricity detection sensor is arranged so as to sandwich a peripheral portion of the semiconductor wafer protruding from the periphery of the measurement stage. And a detector configured to detect the position error of the semiconductor wafer by a change in the amount of light shielded by the peripheral portion.

[0015]

According to the present invention, how much the wafer placed on the measurement stage is displaced from the measurement reference position on the stage (deviation amount) is detected, and when the probe is adjusted to the measurement position, this deviation is detected. The probe is moved to the specified target measurement position on the wafer by correcting the travel distance of the probe and the rotation angle of the measurement table using the amount so that the probe can be accurately positioned.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic structural view showing an embodiment of the present invention, wherein (A) is a plan view, (B) is a right-angled partial side view, the left half is a DO side, and the right. One half shows the OD 'side. FIG. 2 is a block diagram of the embodiment of FIG. In these figures, reference numeral 1 denotes a wafer to be measured. Reference numeral 3 denotes a disk-shaped measurement stage which rotates while placing the wafer 1 thereon, and the radius of which is, for example, about 5 m from the radius of the wafer 1.
m smaller. Reference numeral 2 denotes a DC four-probe probe for measuring the resistivity by bringing four probes into contact with the position of a designated measurement point on the wafer 1. Reference numeral 5 denotes a driving unit (moving mechanism) of the probe 2, on which a four-probe probe 2 is attached at its tip, and moves the probe 2 toward the center of the measurement stage 3 (the center of the wafer is positioned at the center of the measurement stage 3). It has a function of linearly moving in the radial direction (toward the center of the wafer when coincident) and lowering the wafer 1 to an arbitrary designated position.

Reference numeral 4 denotes a rotation drive unit of the measurement stage 3,
The measurement stage 3 can be rotated to any designated angle. By controlling the operations of the rotation drive unit 4 and the probe drive unit 5, the measurement probe 2 can be moved to an arbitrary position on the surface of the wafer 1 and the resistivity of the wafer surface can be measured.

Reference numeral 10 denotes a wafer eccentricity detection sensor using a laser, 11 denotes a light projector, and 12 denotes a light receiver. By measuring the distance of the periphery of the wafer from the center of the measurement stage outside the outer periphery of the measurement stage 3, for example, within a range of about 10 mm, and rotating the wafer 1 once by the rotation drive unit 4, the center of the wafer 1 is Detects the deviation (eccentricity) of the measurement stage 3 from the rotation center and, at the same time, detects the angle (deviation angle) of the notch or orientation flat of the wafer cut into the peripheral edge of the wafer 1 with respect to the measurement reference direction. I do.

The reason why the radius of the measurement stage 3 is made smaller than the radius of the wafer 1 is that the periphery of the wafer 1 is measured by laser light. However, the radius of the measurement stage 3 is not reduced by other means. It goes without saying that the same effect can be obtained if there is a method for measuring the periphery of the wafer 1.

Reference numeral 9 denotes a control unit which reads a signal from the light receiver 12 of the wafer eccentricity detection sensor 10 to calculate the amount of eccentricity of the wafer, corrects the position of the measurement point designated and input from the operation unit 8, and A microcomputer is provided which controls the driving of the two driving units 4 and 5 to bring the probe 2 into descending contact with a target position and causes the measuring unit 6 to perform measurement.

Next, the method of controlling the measurement position according to the present invention, that is, the positioning of the probe will be described. First, a method of measuring the amount of eccentricity of the wafer 1 by the wafer eccentricity detection sensor 10 of the present invention will be described. 3A and 3B are explanatory diagrams of the eccentricity detection sensor 10 for a wafer. FIG. 3A is a side view, and FIG. The light projector 11 has a thin linear beam of light that emits a laser beam from a slit that matches the radial direction of the measurement stage 3. The light beam is aligned in the radial direction toward the center of the measurement stage 3 and hits the light receiver 12. The linear beam is arranged so that a part thereof is shielded from light at an edge portion of the wafer 1 protruding from the periphery of the measurement stage 3.

The light receiver 12 outputs an output voltage proportional to the width of the portion not shielded by the wafer 1 (inversely proportional to the light shielding width d), as shown in FIG. Measurement stage 3
When the center of the wafer 1 placed on the stage is deviated from the center of the measurement stage 3, one turn of the measurement stage 3 changes the light-shielding width d, thereby changing the output. While rotating the measurement stage 3, a constant rotation angle (for example, 0.
Every 1 °), the output voltage due to the change in the light shielding width d is read by a computer (3600 points in one round), whereby the eccentricity and the deflection angle of the wafer 1 can be detected. This will be described later with reference to FIG.

The purpose of this measuring instrument is to measure the resistivity after accurately aligning (positioning) the probe 2 with each of the measurement positions at a number of measurement points on the surface of the wafer 1. The probe driving unit 5 can accurately move the four-probe probe 2 by a specified distance from the rotation center of the measurement stage 3, and the rotation driving unit 4 of the measurement stage 3 is specified from the origin (reference) position. It is a prerequisite to have a function that can rotate the angle accurately. This control can be realized by the number of pulses applied to the pulse motors of the two driving units 4 and 5.

The axis of linear movement of the probe 2 by the probe drive unit 5 is called the R axis, and the angle of rotation of the measurement stage 3 by the rotation drive unit 4 is called the θ axis. For example, the center of the measurement wafer coincides with the rotation center of the measurement stage 3, and the crystal reference direction (notch direction) and the measurement reference direction (probe 2)
The linear movement direction), that is, when the wafer coincides with the measurement reference position for measurement, the center of the wafer and the center of the wafer at 20 m from the center are determined as the measurement points of the wafer.
When two points are designated, m and 90 degrees from the crystal reference direction, the positions of the R axis and the θ axis are as shown in Table 1 below.

[0025]

[Table 1]

Next, a case where the direction of the notch deviates from the measurement reference direction at a position where the center of the measurement wafer deviates from the rotation center of the measurement stage 3 will be described. The amount of eccentricity of the wafer 1 placed on the measurement stage 3 is measured by the sensor 10, and the amount of movement of the specified measurement point on the R axis and θ axis is corrected to determine the exact position of the specified measurement point on the wafer 1. After the determination, the probe 2 is brought into contact with the wafer 1 to measure the resistivity.

The outline of the measurement operation sequence is as follows. (1) Put the measurement stage 3 and the probe 2 at the home position. (2) Place the wafer 1 on the measurement stage 3. (3) The measurement stage 3 is rotated once, and the peripheral position information of the wafer 1 measured by the sensor 10 (a voltage value representing the distance from the rotation center of the measurement stage to the peripheral edge of the wafer 1) is converted to a fixed angle (for example, 0.1 °). ) Read each time. (4) The eccentricity of the wafer 1 and the angular position of the notch or orientation flat are calculated based on the read peripheral position information. (5) Using the eccentricity of the wafer 1 and the angular position information calculated in the above (4), the measurement stage 3 and the probe 2 are positioned at the R-axis and θ-axis positions where the specified measurement position of the wafer 1 is corrected. Move and execute measurement at each specified measurement point.

[0028] FIG. 4 is an explanatory view of an eccentric amount detection of wafer position due to the eccentricity detecting sensor 10, (A) is a wafer Ws was placed on the measurement stage 3 is a plan view obtained by overwriting the W _1, (B) FIG. 6 is an example of output voltage characteristics of the sensor 10 when the wafer is rotated once. The wafer Ws is a reference wafer placed at the measurement reference position of the measurement stage 3, and the center of the measurement stage 3 matches the center of the wafer,
Measurement reference position and wafer reference direction (direction of notch S)
Is consistently listed. The wafer W ₁ is a wafer whose center and angle are shifted with respect to the measurement reference position of the measurement stage 3. The reference wafer Ws is used to correct variations (errors) in the radius of a large number of measurement wafers.
This is a calibration wafer having a known radius Ls, and may be an aluminum disk having the same shape.

The voltage Vs indicated by a dashed line in FIG.
Is the average output voltage of the sensor 10 obtained by rotating the reference wafer Ws once. The voltage Va indicated by a solid line is an average output voltage of a detection signal obtained by rotating the measurement wafer W ₁ by one rotation, and the diameter L of the measurement wafer W ₁ is the calibration reference value V
The difference from s is obtained in addition to the radius Ls of the calibration wafer.
The position of the eccentricity detection sensor 10 is the angle Sd with respect to the reference direction S.
, Is accurately measured and stored as a known value. The sensitivity Sv of the sensor 10, that is, Sv = dV / dL
(Voltage / mm) is determined based on an average output signal obtained by measuring various disks having different radii (radius is known).

The measurement of the wafer is started under the above measurement conditions. First, the wafer 1 to be measured is placed on the measurement stage 3, and the measurement stage 3 is rotated once,
The following information is obtained from the detection signal obtained for each °. (A) Average output voltage Va: The sum of all detection point data is divided by the number of detections (for example, 3600). (B) Maximum eccentricity output Vmax: The maximum eccentricity point Vmax (minimum voltage) is searched from all the detected data. At the same time, the angle of the point from the reference direction s (maximum eccentric point deviation angle α) is obtained. (C) Maximum eccentric point deviation angle α and reference direction angle Sd of the sensor
Find the difference between (D) a mark indicating a reference direction of the wafer W _1, or notch (or orientation flat) position of the output voltage Vn (a value obtained by adding the amount of dent notch) and (notch position), the angle (notch polarized with respect to the reference direction s Angle δ). The notch position detection algorithm calculates the notch depression amount from the proximity data change amount of the detection data. (E) Deviation angle δ of notch position and reference direction angle S of sensor
Find the difference from d.

Next, a description will be given of the measurement position correction function of an arbitrary measurement point P of the wafer W _{1 at} the eccentric position. FIG. 5 is an explanatory diagram showing a specific example of the correction of the measurement point of the wafer. Ws
Is a reference wafer at a reference position, W ₀ is a wafer centered on the reference position, and W ₁ is a wafer at an eccentric position. A line connecting the center C of the wafer W _{1 at} the eccentric position and the notch detection position B is used as a reference line of the wafer W ₁ , and a distance r from the center C and a position of a point P at an angle γ from the reference line are measured. A correction calculation method for obtaining the rotation angle θ of the θ axis of the measurement stage 3 and the moving distance R of the R axis of the probe 2 will be described below.

First, the symbols shown in FIGS. 4 and 5 are applied to the data of the wafer W ₁ at the eccentric position which is easily calculated from the detection signal information of the above item (3), and is shown below. (A) Calculation of radius L: L (mm) = {(Vs−Va)} Sv｝ + Ls─── (1) (b) Maximum eccentric value: a (mm) = (Va−Vmax) {Sv} ────── (2) (c) Distance from center O of measurement stage 3 (wafer W _{0 at} reference position) to notch position B: OB (mm) = {(Vn−Va) ÷ Sv} + L ──────── (3) (d) the difference between the notch deviation angle [delta] and the maximum eccentricity point deviation angle α: ∠MOB = δ-α─ ( 4) ( e) the center C of the wafer W ₁ Is a point having a maximum point deviation angle α from the reference direction OS and a distance a (mm) from the center O on a line toward the maximum eccentric point M. That is, OC = a─────────────────────── (5)

The position of the point P to be obtained, that is, the distance R from the center O of the measuring stage 3 to the point P and the angle θ from the reference direction OS are obtained by focusing on the triangle OCP in FIG. (The cosine law is that if the sides of a triangle are a, b, c and the corresponding angles are A, B, C, then a = bcos C + cco
s B, a ² = b ² + c ² -2 bc cos A )

First, the R-axis distance R to be obtained is obtained by the following equation (6) using equations (2) and (5).

(Equation 2)

Next, assuming that β of ∠OCP in FIG. 5 is β, β is obtained as follows.

Β = ∠OCP = ∠OCB−γ (7) ∠OCB = 180 ° −∠MOB−∠OBC (8) Substituting equation (4) into equation (8), rearranging equation (7) Then β
Is expressed by the following equation (9).

Β = 180 ° − (δ−α) −∠OBC-γ (9)

Here, ∠OBC is given by the following equation (10) using equations (1), (2), (3) and (5) according to the cosine law.
Indicated by

∠OBC = cos ⁻¹ [{L ² + (OB) ² −a ² ｝ ÷ ｛2L × (OB)}] (10)

Next, the angle θ of the θ axis to be obtained can be obtained from the following equation (11) using the equation (6), similarly according to the cosine law.

Θ = cos ⁻¹ [{a ² + R ² −r ² } 2a × R} + α] (11)

As described above, the P and P specified as the measurement points of the wafer W ₁ whose center and the angle deviate from the measurement reference position are set.
At a point (a distance r from the center C of the wafer W ₁ ,
_When R and θ at the measurement reference position (the point at an angle γ from the direction of the notch position ₁ ) are obtained, the rotation drive unit 4 rotates the measurement stage 3 by the angle θ, and the probe drive unit 5 sets the probe 2 at the reference center. move from point O to the reference direction to a point distance R, is lowered to the wafer W ₁ to measure the resistivity of the P point.

For example, when the radius of the measuring stage 3 is made smaller than the radius of the wafer by 5 mm and the peripheral edge of the wafer is measured with a width of 10 mm by the eccentricity detecting sensor, an automatic wafer transfer machine (wafer transport robot) moves the wafer to the measuring stage. The deviation of the center of the wafer when mounted on
Even if the distance is 5 mm, the position error of the measurement point of the wafer is ± 0.
It can be less than 2 mm. However, in practice, the displacement (deviation) of the wafer mounting position by the automatic wafer transfer machine can be suppressed to about ± 2 mm or less, so that the position error of the measurement point of the wafer is sufficiently ± 0.1 mm. It can be:

The number of measurement points per wafer is, for example, 1 point to 17 points for standard measurement and 11 points to 36 points for multipoint measurement.
In practice, many points of intersection between radiation from the center and multiple concentric circles are specified, and one point is measured in a few seconds, and high-speed arithmetic processing and control are performed so that the measurement is completed in a short time. Will be

[0041]

As described in detail above, by carrying out the present invention, in a resistivity measuring system with an automatic wafer transfer machine, (1) a wafer to be measured is measured on a measuring stage of the resistivity measuring device. Since the deviation from the reference position can be detected with high accuracy, the probe is moved to the specified measurement point of the wafer at the eccentric position by correcting using the detected data.
It is possible to measure by accurately aligning and positioning with an accuracy of 0.1 mm or less. (2) Since the positional accuracy has been improved, it is possible to accurately measure the resistivity up to near the periphery of the wafer. (3) Since the wafer may be directly transferred from the cassette to the measurement stage of the resistivity measuring instrument, an expensive orientation flat aligner is not required. Practical technical, productive, etc.
The economic effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of an embodiment of the present invention.

FIG. 2 is a block diagram of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a wafer eccentricity detection sensor which is a part of the present invention.

FIG. 4 is an explanatory diagram of detecting the amount of eccentricity of a wafer.

FIG. 5 is a detailed explanatory diagram of a measurement point correction amount of a wafer.

FIG. 6 is a plan view of a semiconductor wafer.

FIG. 7 is a diagram illustrating the principle of the DC four-point probe method.

FIG. 8 is a schematic diagram of a conventional resistivity measuring device.

FIG. 9 is a schematic structural diagram of a conventional resistivity measuring instrument.

FIG. 10 is a block diagram of a conventional resistivity measuring instrument.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2 4 Probe probe 3 Measurement stage 4 Rotation drive unit 5 Probe drive unit 6 Measurement unit 7 Control unit 8 Operation unit 9 Control unit 10 Wafer eccentricity detection sensor 11 Light emitter 12 Light receiver 20 Cassette 21 Orifice flatter 22 Chuck stage 23 Edge sensor 24 Transfer robot 25 Resistivity measuring device

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[Procedure amendment]

[Submission date] August 24, 1999 (1999.8.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013]

SUMMARY OF THE INVENTION A semiconductor wafer resistivity measuring instrument according to the present invention comprises a rotatable disk-shaped measuring stage on which a semiconductor wafer to be measured is mounted, a rotary drive for rotating the measuring stage, A four-hand probe for measuring the resistivity by contacting a predetermined position on the upper surface of the semiconductor wafer placed on the measurement stage, and moving the four-hand probe in the radial direction and the vertical direction of the measurement stage A probe driving unit to be operated, an operation unit for designating and inputting the position of a resistivity measurement point on the upper surface of the semiconductor wafer, and driving the rotation driving unit and the probe driving unit in accordance with the designation input inputted to the operation unit, and 4 at the designated position
In a semiconductor wafer resistivity measuring device provided with a control unit for measuring a resistivity by contacting a short-needle probe, the measuring device protrudes from the measuring stage in the vicinity of the periphery of the measuring stage.
The wafers are projected facing each other with the periphery of the
An optical device and a light receiver are arranged, and the light emitted from the light emitter is provided.
A thin linear laser beam in the radial direction of the measurement stage
Changes in the amount of light blocked by the edge are reflected to the light receiver.
Therefore, it was converted to the received light voltage value and mounted on the measurement stage.
Distance from the center of the measurement stage to the periphery of the semiconductor wafer
The control unit measures the distance from the center of the measurement stage around the periphery of the semiconductor wafer by the wafer eccentricity detection sensor when the semiconductor wafer is mounted on the measurement stage. By detecting the position error of the center position of the semiconductor wafer and the crystal reference direction with respect to the measurement reference position of the measurement stage, the position of the measurement point on the upper surface of the semiconductor wafer specified and input from the operation unit. Operate the rotation drive unit and the probe drive unit to make contact with the four short needle probe
When Ru is, it is characterized in that it has been configured to measure before Symbol position precise resistivity measurement position obtained by adding a correction value calculated from置誤difference.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Deleted

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Haruki Hiruda, Inventor 2-8-3 Nagaoka, Mizuho-machi, Nishitama-gun, Tokyo Inside Kokusai Denki Eltec Co., Ltd. (72) Toshiaki Tanaka 2-8 Nagaoka, Mizuho-cho, Nishitama-gun, Tokyo -3 Kokusai Denki Eltec Co., Ltd. (72) Kazuhiko Kinoshita 2-8-3 Nagaoka, Mizuho-cho, Nishitama-gun, Tokyo F-term within Kokusai Denki Eltec Co., Ltd. 2G028 AA01 AA03 BB11 BC01 CG02 DH03 DH17 FK01 HN11 HN13 JP02 JP04 LR02 4M106 AA01 BA14 CA10 DH09 DH12 DH32 DH51 DJ03 DJ06 DJ07 DJ19

Claims (2)

[Claims] 1. A rotatable disk-shaped measurement stage on which a semiconductor wafer to be measured is mounted, a rotation drive unit for rotating the measurement stage, and a predetermined surface of a semiconductor wafer mounted on the measurement stage. A probe drive for measuring the resistivity by contacting the position of the probe, a probe driving unit for moving the four probe in the radial direction and the vertical direction of the measurement stage, and the resistivity of the upper surface of the semiconductor wafer. An operation unit for designating and inputting the position of the measurement point, and driving the rotation drive unit and the probe drive unit according to the designation input input to the operation unit, and bringing the four probe probe into contact with a designated position on the upper surface of the semiconductor wafer. A semiconductor wafer resistivity measuring device provided with a control unit for measuring the resistivity of the semiconductor wafer, the semiconductor wafer being provided near the periphery of the measurement stage, and being mounted on the measurement stage. A wafer eccentricity detection sensor that measures a distance from the center of the measurement stage to a periphery of the wafer, wherein the control unit, when a semiconductor wafer is placed on the measurement stage, the wafer eccentricity detection sensor detects the periphery of the semiconductor wafer. The position error of the semiconductor wafer with respect to the measurement reference position of the measurement stage is detected by measuring the distance from the center of the measurement stage over one round, and the rotation is performed to the position of the measurement point of the semiconductor wafer specified and input from the operation unit. When operating the drive unit and the probe drive unit, the probe probe is brought into contact with a position taking into account the correction value calculated from the detected position error to measure the resistivity. Characteristic semiconductor wafer resistivity meter. 2. The measurement stage has a radius smaller than a radius of a semiconductor wafer to be mounted, and the wafer eccentricity detection sensor is arranged so as to sandwich a peripheral portion of the semiconductor wafer protruding from the periphery of the measurement stage. 2. A semiconductor wafer according to claim 1, wherein said semiconductor wafer comprises a laser light projector and a light receiver, and wherein said position error of said semiconductor wafer is detected by a change in a light blocking amount blocked by said peripheral portion. Resistivity measuring instrument.