JPH08248073A - Resistivity meter - Google Patents

Abstract

PURPOSE: To obtain a resistivity meter for measuring the resistivity of samples having significantly different thickness while sustaining the accuracy and minimizing the measuring time. CONSTITUTION: The resistivity meter comprises a measuring head 6 movable up and down through an up/down drive section 5, and a measuring pin 7 in the measuring head which abuts against a sample 9 in order to measure the resistivity thereof, wherein the operation range for measurement is variable depending on the thickness of the sample 9 and a minimum necessary range is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistivity measuring machine for measuring the resistivity of silicon wafers and the like.

[0002]

2. Description of the Related Art A resistivity measuring machine has a pair of measuring pins which can be moved up and down, a stage on which a sample is mounted,
It has an elevating and lowering drive unit for elevating and lowering the measuring head, and a resistance measuring unit for measuring resistance between the pair of measuring pins.

When measuring the resistivity of a film formed on a silicon wafer, the silicon wafer is placed on the stage, the measuring head is lowered, and the measuring pins are brought into contact with the silicon wafer with a required contact pressure. The resistivity of the silicon wafer is measured by supplying a required current between the measurement pins and measuring the voltage between the measurement pins.

[0004]

In the above-mentioned conventional resistivity measuring machine, the operating range of the measuring head is fixed, and the moving time of the measuring head is the longest and the large proportion of the total time required for the measurement. Occupy Therefore, in order to reduce the total measurement time, it is necessary to limit the moving time of the measuring head, that is, the moving distance of the measuring head.
In the conventional resistivity measuring machine, the position of the operating range of the measuring head is determined according to the thickness of the sample to be measured, and the operating range is also limited to the minimum required operating distance.

Therefore, there is a limit to the change in the thickness of the sample that can be measured, and there is a problem that the sample having a large thickness cannot be measured.

In order to deal with such a limitation of the thickness of the sample, it is conceivable to increase the operating distance of the measuring head so as to cope with the change in the thickness of the sample and increase the ascending / descending speed of the measuring head. There was a problem of causing the decrease of.

In view of the above circumstances, the present invention provides a resistivity measuring instrument capable of measuring the resistivity of samples having greatly different thicknesses while maintaining the measurement accuracy and minimizing the measurement time. It is a thing.

[0008]

SUMMARY OF THE INVENTION The present invention provides a resistivity measuring instrument for measuring the resistivity of a sample by allowing the measuring head to be raised and lowered by an elevation drive unit and bringing the measuring pin of the measuring head into contact with the sample. It is configured to move the measurement operation range according to the thickness of the sample, and further has an up / down position adjustment unit that can change the vertical position of the measurement head between the elevation drive unit and the measurement head, or moves the measurement head up and down. And a control unit for controlling the elevating motor so as to elevate between the ascending position and the descending position by calculating the ascending position and descending position of the measuring operation range of the measuring head based on the input sample thickness. It is characterized by having.

[0009]

[Function] The measurement operation range is moved according to the thickness of the sample to minimize the measurement operation range itself, and the movement of the measurement operation range is adjusted by the vertical position adjusting unit or the control unit according to the thickness of the sample. The position of the measurement operation range is calculated, and the motor is controlled at the calculated position to move the measuring head up and down.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a base, on which a measuring arm 3 is provided via an elevating guide 2.
A lift drive unit 5 is connected to the measurement arm 3 via a vertical position adjustment unit 4. A measuring head 6 is provided on the lower surface of the tip of the measuring arm 3, and the measuring head 6 has a measuring pin 7. The measuring pin 7 is electrically connected to a resistance measuring unit (not shown). Below the measuring head 6,
A stage 8 is provided on the base 1, and a sample 9 is placed on the stage 8.

As the elevating / lowering drive unit 5, a structure in which a screw is rotated by a motor to move the vertical position adjusting unit 4 up and down, a structure in which a vertical motor moves the vertical position adjusting unit 4 up and down, and an air cylinder moves the vertical position adjusting unit 4 up and down And the like having a structure that allows

The vertical position adjusting unit 4 is constructed so that the vertical position of the measuring arm 3 can be changed. For example, the vertical position adjusting unit 4 is a detachable rod, and a plurality of rods having different lengths are prepared. , The position of the measuring arm 3 can be changed by exchanging the rod, or the vertical position adjusting part 4 is composed of two or more members and is slidably combined in the vertical direction, and can be expanded and contracted using a screw mechanism or the like. It is what

The operation will be described below.

Vertical position adjusting unit 4 according to the thickness of the sample 9
The position of the measuring arm 3 is determined by. The sample 9 is placed on the stage 8, the elevating and lowering drive unit 5 is driven to lower the measuring arm 3, and the measuring pin 7 is brought into contact with the sample 9.
The measuring pin 7 is energized and the resistivity is measured. When the measurement is completed, the elevating and lowering drive unit 5 raises the measuring arm 3. The sample 9 is replaced with a new one and the resistivity measurement is continued.

Next, when the thickness of the sample 9 is changed, the position of the measuring arm 3 is changed by the vertical position adjusting section 4.
For example, when the thickness of the sample 9 is increased, the length of the vertical position adjusting unit 4 is changed to a long rod, or the screw mechanism is operated to extend the vertical position adjusting unit 4.

When the position of the measuring arm 3, that is, the position of the measuring head 6 is changed by the vertical position adjusting unit 4, the measuring head 6 is within the measuring operation range required for measurement at the changed position. Move up and down. Therefore, the position of the measuring head 6 can be set to an appropriate position with respect to the thickness of the sample 9 by the vertical position adjusting unit 4, and the operating distance for the elevating / lowering drive unit 5 to move the measuring arm 3 up and down is the minimum. The same distance is sufficient regardless of the thickness.

FIG. 2 shows another embodiment.
In the embodiment shown in (1), the measurement operation range of the measurement arm 3 is moved by electrical processing. In FIG. 2, the same parts as those shown in FIG. 1 are designated by the same reference numerals.

A slider 12 is provided on a frame 10 via a guide rod 11 so as to be movable up and down, a measuring arm 3 is provided on the slider 12, and a measuring head 6 is provided at the tip of the measuring arm 3. Also, the guide rod 1
A screw 13 parallel to 1 is rotatably provided, and the screw 13 is screwed to the slider 12.
A lifting motor 14 is connected to the screw 13, and the lifting motor 14 is driven by a controller 15.

In the figure, 16 is an input unit, 17 is a thickness sensor, and 18 is an encoder for detecting the rotation angle of the lifting motor 14.

The thickness of the sample 9 is detected by the thickness sensor 17, and the detection result is input to the controller 15.
The control unit 15 drives the elevating motor 14 to move the measuring arm 3 to an appropriate position with respect to the sample 9 via the slider 12. Further, the control unit 15 controls the input sample 9
The ascending position and the descending position of the measuring operation range of the measuring head 6 are calculated based on the thickness of the. The elevating motor 14 is controlled by the control unit 15, and the resistivity measurement is performed by elevating and lowering the measurement head 6 within the measurement operation range calculated by the control unit 15. The elevating range of the measurement head 6 is the minimum required for measurement. The operating range is limited. That is, the descending position and ascending position of the measuring head 6 are controlled by the control unit 15 according to the thickness of the sample 9, and the difference in elevation of the measuring head 6 is set to a minimum operating distance.

The thickness of the sample 9 is often known in advance or may be measured in advance. In this case, the operator controls the thickness of the sample 9 by the input unit 16 before starting the measurement. You may enter in.

In this embodiment, it is possible to easily cope with the case where the thickness of the sample 9 changes frequently.

[0024]

As described above, according to the present invention, since the operation reference position of the measuring head is changed with respect to the thickness of the sample, even if the sample has various thicknesses such as a wafer shape or a block shape, it can be easily performed. It is possible to measure, and since the operating range at the time of measurement is the minimum for a sample of any thickness, the measurement time is shortened and it is not necessary to increase the operating speed, so it is reliable without lowering the measurement accuracy. Sex increases.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a first embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a second embodiment of the present invention.

[Explanation of symbols]

 2 Lifting guide 3 Measuring arm 4 Vertical position adjusting unit 5 Lifting drive unit 6 Measuring head 7 Measuring pin 9 Sample 12 Slider 13 Screw 14 Lifting motor 15 Control unit 16 Input unit 17 Thickness sensor

Claims (3)

[Claims] 1. A resistivity measuring machine for measuring the resistivity of a sample by allowing the measuring head to move up and down by an elevating and lowering drive unit and contacting the measuring pin of the measuring head with the sample to measure the thickness of the sample. A resistivity measuring machine characterized by being configured to move the operating range. 2. The resistivity measuring machine according to claim 1, further comprising an up-and-down position adjusting unit provided between the elevating and lowering drive unit and the measuring head, the up-down position adjusting unit being capable of changing the up-down position of the measuring head. 3. A motor for moving up and down the measuring head, and an ascending position and a descending position of the measuring operation range of the measuring head are calculated based on the inputted thickness of the sample, and the ascending and descending position is raised and lowered. The resistivity measuring machine according to claim 1, further comprising a control unit that controls the lifting motor.