JPH05335393A - Noncontact electric measuring apparatus of semiconductor wafer - Google Patents

Abstract

PURPOSE:To form a structure for a semiconductor wafer from dust particles. CONSTITUTION:In the electric measurement of a semiconductor wafer, a partition plate 620 is situated at the lower part of a measuring chamber MR and forms a ventilation passage in which the clean air which has been supplied to the measuring chamber MR is guided to an evacuation chamber ER at the lower part of an enclosure. On the other hand, when the semiconductor wafer is carried in, or carried out from, the enclosure, the partition plate 620 is moved to the lower part of a carrying-in chamber TR, and the clean air which has been supplied to the measuring chamber MR is discharged to the outside via an opening part in a lid 32. The partition plate 620 serves to keep dust particles from a sensor head 60 and the semiconductor wafer 100.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact electric measuring apparatus for measuring electric characteristics of a semiconductor wafer such as a CV curve in a non-contact manner.

[0002]

2. Description of the Related Art As one of methods for evaluating a semiconductor process having a MIS structure, an evaluation method by CV measurement is used. In the conventional CV measurement, it was necessary to form an electrode for electrical measurement on the surface of the oxide film on the semiconductor substrate, but the electrode formation process only affects the electrical characteristics of the semiconductor wafer itself. Without. There is a problem that the electrode formation itself takes time and effort. Therefore, the applicant of the present invention has developed an electric measuring apparatus for a semiconductor wafer, which can perform electric characteristic evaluation such as CV measurement and Ct measurement without forming electrodes on the surface of the semiconductor wafer. FIG. 1 is a conceptual diagram showing an outline of a semiconductor non-contact electrical measuring device developed by the present applicant. In FIG. 1A, an oxide film 102 is formed on the front surface of a semiconductor substrate 101, and an electrode 202 is formed on the back surface.
Above the oxide film 102, the electrode 201 for measurement is hold | maintained by the electrode holding unit 300 across the gap Ge. The gap Ge between the oxide film 102 and the measuring electrode 201 is set to about 1 μm or less so that the electrode holding unit 3
Controlled by 00.

The capacitance Ct between the two electrodes 201 and 202 is, as shown in FIG. 1B, the semiconductor substrate 101.
Cs, the capacitance Ci of the oxide film 102, and the capacitance Cg of the gap Ge are connected in series.
The C-V curve is the voltage dependence of the combined capacitance Cta of the capacitance Cs of the semiconductor substrate 101 and the capacitance Ci of the oxide film 102. The value of the gap Ge is accurately measured by the electrode holding unit 300, and the capacitance Cg of the gap is calculated based on the value of the gap Ge. The combined capacity Ct is measured by the measuring unit 400, and the combined capacity Ct is
The CV curve is determined by subtracting the electrostatic capacitance Cg of the gap from the above to obtain the capacitance Cta.

[0004]

In this non-contact electric measuring device, the gap Ge between the electric measuring electrode 201 and the semiconductor wafer is measured in a state of about 1 μm or less.
If a minute dust is caught between the electrode wafer and the wafer, the sensor head may be broken or the measurement error may be increased. However, when a semiconductor wafer is loaded into or unloaded from the apparatus, dust is likely to enter from the outside. Therefore, it is necessary to take dust measures to reduce the invasion of dust into the apparatus especially when loading / unloading wafers. However, conventionally, a device for non-contact electrical measurement of a semiconductor has not been known, and a device having a structure capable of reducing intrusion of dust has not been known.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a non-contact electric measuring device capable of reducing the intrusion of dust on a semiconductor wafer.

[0006]

In order to solve the above-mentioned problems, a non-contact electrical measuring apparatus according to the present invention is provided with (a) a reflecting surface which is held substantially parallel to a surface of a semiconductor wafer with a gap therebetween. And a gap between the gaps based on the intensity of the laser light introduced into the transparent member and reflected by the reflecting surface. And (b) a movable sample stage on which the semiconductor wafer is mounted, and (c) a sensor head for measuring the electrical characteristics of the semiconductor wafer using the electrical measurement electrodes. A housing provided with an openable / closable lid for accommodating the sensor head and the sample table, and a carrying-in chamber for carrying in or carrying out a semiconductor wafer to the sample table when the sample table is located inside the lid. , The carrying A housing provided with a measurement chamber communicating with the chamber and provided at the position of the sensor head, and an exhaust chamber having an exhaust port; (d) gas supply means for supplying dedusted gas to the measurement chamber; ) A partition plate that moves together with the sample table. This partition plate opens a ventilation path from the carry-in chamber to the exhaust chamber when the sample stage is located in the measurement chamber, whereby the gas supplied to the measurement chamber is passed through the carry-in chamber. While guiding the gas to the exhaust chamber and discharging the gas, the gas passage supplied to the measurement chamber is blocked when the semiconductor wafer is loaded into or unloaded from the sample stage located in the loading chamber. It is discharged to the outside through the chamber and the opened lid.

[0007]

When the sample stage is located in the measurement chamber, dust-removed gas is released to the outside through the measurement chamber, the carry-in chamber, and the exhaust chamber, so that it is possible to reduce the intrusion of dust from the outside onto the semiconductor wafer. it can. On the other hand, when the sample table moves to the carry-in chamber and the semiconductor wafer is carried in or out of the sample table, dust-removed air passes through the measurement chamber and the carry-in chamber and is released to the outside from the open lid. It is possible to reduce the intrusion of dust on the semiconductor wafer.

[0008]

EXAMPLES A. FIG. 2 is a schematic diagram of the apparatus. As an embodiment of the present invention, FIG.
It is a conceptual diagram which shows the structure of D. This non-contact electrical measuring device MD includes a measuring section unit 20 for accommodating a semiconductor wafer 100, a light quantity measuring device 22, and an impedance meter 24.
A position controller 26 and a host controller 28. Light quantity measuring device 22 and impedance meter 2
4 and the position control device 26 are connected to a host controller 28, and the host controller 28 controls the entire measuring device and processes the obtained data. A personal computer, for example, is used as the host controller 28.

The measuring unit 20 is housed inside a housing 30 mounted on a vibration isolation table 21. The housing 30 includes a gantry 36 that moves in the X direction and a sample table 38 that is placed on the gantry 36. Sample table 38
Is a table on which the semiconductor wafer 100 as a sample is placed, and is driven by a motor (not shown) to rotate in the XY plane.

An openable and closable flange 42 is fixed by a bolt to the opening at the top of the housing 30 of the measuring unit 20, and a piezo element is used below the flange 42.
Two piezoelectric actuator sections 44, 45, 46 are provided. Further, the piezoelectric actuator units 44, 45, 4
A support plate 48 is provided below the support plate 6, and
The sensor head 60 is provided at the tip of the support cylinder 50 extending to the lower side of
Is fixed. The support plate 48 is connected to the flange 42 by a plurality of springs (not shown), and pushes up the piezoelectric actuator portions 44, 45, 46 to the flange 42 side. The sensor head 60 includes a right-angle prism 62 for introducing laser light, and a translucent electrode forming portion 64 adhered to the bottom surface of the right-angle prism 62 with an optical adhesive. In this way, the flange 42 that can be opened and closed
Since the entire supporting portion that supports the sensor head 60 is attached to, it is easy to replace the entire supporting portion with the flange 42 opened.

Above the flange 42, pulse motors 80, 81, 82 connected to the piezoelectric actuator portions 44, 45, 46, respectively, are provided. These pulse motors 80 to 82 roughly adjust the vertical direction and parallelism of the sensor head 60. On the other hand, the piezoelectric actuator sections 44 to 46 also have a role of performing fine adjustment in the vertical direction of the sensor head 60 and adjusting the parallelism of the bottom surface of the electrode forming section 64.

A laser oscillator 70 such as a GaAlAs laser and a light receiving sensor 72 such as a photodiode are fixed to the support cylinder 50. The laser light emitted from the laser oscillator 70 passes through the right-angle prism 62 and the electrode forming portion 6
4 and is reflected on the bottom surface of the electrode forming portion 64 under the condition of geometrical optical total reflection. Then, the reflected laser light is emitted from the rectangular prism 62 and received by the light receiving sensor 72.

During the electrical measurement of the semiconductor wafer 100, the gap between the bottom surface of the sensor head 60 and the surface of the semiconductor wafer 100 is kept at about 1 μm or less. The optical system including the laser oscillator 70, the sensor head 60, and the light receiving sensor 72 is an optical measuring system for precisely measuring this gap. This optical measurement system uses a laser oscillator 7
The tunneling phenomenon of the laser light when the laser light oscillated from 0 is reflected by the bottom surface of the sensor head 60 under the condition of geometrical optical total reflection is measured by the light receiving sensor 72 and the light quantity measuring device 22. The gap value is measured based on the amount of light. The method of measuring the gap is described in detail in Japanese Patent Application Laid-Open No. 4-32704 disclosed by the present applicant, and thus the details thereof will be omitted here.

The piezoelectric actuators 44 to 46 and the pulse motors 80 to 82 are electrically connected to the position control device 26, and the light receiving sensor 72 is connected to the light quantity measuring device 22 and is formed on the bottom surface of the sensor head 60. The formed electrodes and the metal sample table 38 are connected to the impedance meter 24. The impedance meter 24 is a device that measures the capacitance and conductance between each electrode and the sample table 38.

FIG. 3A is a bottom view of the electrode forming portion 64, and FIG. 3B is a BB sectional view thereof. Electrode forming part 64
Is composed of a cone glass 66 formed of optical glass and an electrode pattern 200 formed on the bottom surface 66a of the cone glass 66. The electrode pattern 200 includes an electric measurement electrode 201 and three parallelism adjustment electrodes 111.
To 113 and a guard ring 120, and wirings 201a, 111a to 113a, 120a connected to the electrodes 201, 111 to 113, 120, respectively.
Is included. These wirings are formed from the bottom surface 66a of the cone glass 66 to the side slope surface 66b. The cone glass 66 is obtained by polishing a disk-shaped glass and cutting the side surface into a tapered shape.

The electrode 201 for electrical measurement is a ring-shaped electrode, and the cone glass surface exposed at the center thereof is a reflecting surface 66c on which the laser beam L is totally reflected geometrically. Each of the three parallelism adjusting electrodes 111 to 113 has a ring shape that is equally divided into three.
The parallelism adjusting electrodes 111 to 113 are cone glass 66.
This is an electrode used when adjusting the parallelism between the bottom surface 66a of the substrate and the surface of the semiconductor wafer 100. That is, if the expansion amount of the piezo elements of the piezoelectric actuator portions 44, 45, 46 is adjusted to adjust the inclination of the bottom surface 66a of the cone glass 66 and the capacitance values of the electrodes 111 to 113 are made equal to each other, the cone The bottom surface 66a of the glass 66 and the surface of the semiconductor wafer 100 can be parallel to each other.

The guard ring 120 is used for the electrode 2 for electrical measurement.
01 and the parallelism adjusting electrodes 111 to 113 are ring-shaped electrodes. The guard ring 120 is kept at a predetermined potential (for example, ground potential) and has a role of preventing an interaction between the four electrodes 201 and 111 to 113.

FIG. 4 is a front view showing a connection state of the wiring of the sensor head 60. Wiring 111 on cone glass 66
a to 113a, 120a, 201a are cone glasses 6
An external lead wire 116 is connected at the end of the side sloped surface 6. The wiring is connected by wire bonding or curable silver paste.

B. Anti-Vibration Countermeasure Structure This non-contact electrical measuring device MD measures the electrical characteristics while keeping the gap between the sensor head 60 and the semiconductor wafer 100 at about 1 μm or less, so that a small external vibration causes the sensor head 60 or When transmitted to the semiconductor wafer 100, the measured value vibrates and the measurement error increases. Therefore, anti-vibration measures are important to maintain high measurement accuracy. FIG. 5 is a perspective view showing the measuring unit 20 mounted on the vibration isolation table 21. The anti-vibration table 21 and the housing 30 play an interpolative role in anti-vibration measures. The anti-vibration table 21 has a function of preventing external vibration of a relatively high frequency of about 2 Hz or higher,
The housing 30 has a function of preventing external vibration of relatively low frequency. As the vibration isolation table 21, for example, a desk type vibration isolation table 60 series (trade name) of Kurashiki Kako Co., Ltd. can be used. The housing is made of an aluminum plate with a thickness of 2 cm, and its outer shape is approximately 32 cm (W) x 50 cm (L) x
It is 23 cm (H). A portion of about 20 cm in front of the housing 30 is cut off by about 8 cm from the upper end, and a lid 32 that can be opened and closed is provided there.

Since the box-shaped housing 30 is constructed as a solid structure made of metal as described above, it has an effect of suppressing vibration of relatively low frequency. However, since the strong structure resonates with vibration of relatively high frequency, the vibration isolation table 2
1 eliminates high frequency vibration. That is, the combination of the vibration isolation table 21 and the housing 30 suppresses the vibration of a wide range of frequencies and the fluctuation of the relative position between the semiconductor wafer 100 and the sensor head 60.

FIG. 6 is a graph showing various measurement results in the electric measuring device MD after such anti-vibration measures.
The amount of gap variation calculated back from the variation of each measured value is 2 nm or less, and the measurement error due to this variation is negligible. Therefore, it can be seen that the above-mentioned anti-vibration measures are effective.

C. Dust Countermeasure Structure FIG. 7 is a cross-sectional side view of a main part of the measuring unit 20.
Below the flange 42 on the top of the housing 30, the sensor unit 520 including the above-described piezoelectric actuator units 44 to 46 and the sensor head 60 is provided. The above pulse motors 80 to 82 are provided above the flange 42. Further, the sensor cover 530 is provided around the sensor unit 520.
It is surrounded by. In the upper space inside the housing 30, the diffusion nozzle 54 surrounds the sensor cover 530.
0 is set.

FIG. 8 is a cross-sectional plan view of the main part of the measuring section unit. The opening 540a of the diffusion nozzle 540 is fitted into the opening of the housing 30, and the cross section of the diffusion nozzle 540 is enlarged as it enters the inside of the housing 30. The diffusion nozzle 540 has a function of preventing vortices from being generated in the air blown from the blower 90 (FIG. 7). By gently enlarging the cross section of the diffusion nozzle 540, the generation of vortices is prevented. The reason why the generation of the vortex is prevented is that dust is rolled up by the vortex and easily adheres to the sensor head 60 and the semiconductor wafer 100 when the vortex exists.

A drive device 610 for driving the sample table 38 and the gantry 36 in the X direction is provided in the lower portion of the housing 30, and a partition plate 620 is connected to the ball screw portion 612 of the drive device 610. On the upper part of the partition plate 620, the pedestal 36 and the sample table 38 described above are placed. Further, the leg portion 622 of the partition plate 620 is the linear guide 6
It is engaged with 30. When the driving device 610 moves the ball screw portion 612 in the X direction, the partition plate 620 moves along the linear guide 630, and the gantry 36 and the sample table 38 also move together with the partition plate 620. FIG. 7 shows a state in which the sample table 38 is located below the sensor head 60, and in this state, electrical measurement of the semiconductor wafer 100 is performed.

In FIG. 7, the white arrow indicates the flow of air. At the outlet of the blower 90, an air filter having a mesh of about 0.3 μm or less is installed, and dust in the air is removed here. The blower 90 has a blowout port provided by a hose (not shown) with an opening 540 of the diffusion nozzle 540.
The dust-removed air blown from the blower 90 is blown into the diffusion nozzle 540. As shown in FIGS. 7 and 8, the partition plate 620 divides the inside of the housing 30 into upper and lower parts so that the air blown into the diffusion nozzle 540 does not immediately flow into the exhaust chamber below the housing 30. .. Therefore, a considerable part of the air blown into the diffusion nozzle 540 reaches the vicinity of the lid 32 in front of the housing 30. This air is separated by the partition plate 62.
It is guided to the lower part of the housing 30 from a portion where there is no 0, and is discharged from an exhaust port 640 provided at the rear of the lower part of the housing. The exhaust port 640 is connected to the intake port of the blower 90 by a hose (not shown).

In FIG. 7, the portion where the sensor portion 520, the sensor cover 530, and the diffusion nozzle 540 are present corresponds to the measurement chamber MR. The space inside the lid 32 corresponds to the carry-in chamber TR, and the portion below the partition plate 620 corresponds to the exhaust chamber ER. Since a large number of mechanical driving parts are housed in the exhaust chamber ER below the housing 30, it becomes a source of dust generation. Therefore, the partition plate 620 partitions the measurement chamber MR and the exhaust chamber ER, and the air supplied to the measurement chamber MR is discharged to the outside through the exhaust chamber ER at the end.
Dust is prevented from flowing onto the semiconductor wafer 100 and near the sensor.

A part of the air blown into the opening 540a of the diffusion nozzle 540 passes through the inside of the sensor cover 530 and is exhausted from an exhaust port 510 provided in a part of the flange 42. The exhaust port 510 is also connected to the intake port of the blower 90 by a hose (not shown). The dust generated in the vicinity of the sensor head 60 is discharged from the upper exhaust port 510, so that the dust can be prevented from adhering to the semiconductor wafer 100 and the sensor.

FIG. 9 shows a state in which the sample table 38 is located in the loading chamber TR below the lid 32, and the semiconductor wafer 100 is loaded and unloaded in this state. Figure 10
Is the partition plate 620 and the diffusion nozzle 54 in the state of FIG.
It is a partial cross section top view which shows the positional relationship of 0. However, in FIG. 10, the pedestal 36, the sample table 38, etc. are not shown.

As shown in FIG. 9, the end portion of the partition plate 620 overlaps with the projecting portion 30a provided inside the front of the housing 30, whereby the carry-in chamber TR to the exhaust chamber ER.
Has blocked the passage to.

In the state shown in FIG. 9, almost all of the air blown from the blower 90 passes through the diffusion nozzle 540 and is then discharged to the outside through the opening of the lid 32 as shown by the arrow. A part of the air supplied to the measurement chamber MR passes through the inside of the sensor cover 530 and is discharged from the exhaust port 510 of the flange 42.

When loading / unloading the semiconductor wafer 100, the inside of the housing 30 is opened to the outside, but by removing the dedusted air from the opening of the lid 32 to the outside, the external dust is put inside the housing. Prevents inflow.

As described above, the partition plate 620 is located under the measurement chamber MR during the electrical measurement of the semiconductor wafer (FIG. 7), and clean air supplied from the blower 90 to the measurement chamber MR is removed. A ventilation path leading to the exhaust chamber ER at the bottom of the housing is formed.
On the other hand, when the semiconductor wafer is loaded into or unloaded from the housing (FIG. 9), the partition plate 620 moves below the loading chamber TR, and the clean air supplied to the measurement chamber MR passes through the opening of the lid 32. It is discharged to the outside through. The function of the partition plate 620 prevents dust from adhering to the sensor head 60 and the semiconductor wafer 100.

D. Other Structural Features A window 34 with a lid shown in FIG. 5 is provided on the side surface of the housing 30. FIG. 8 shows a state in which the lid 35 of the window 34 is opened. A convex lens is fitted in the window 34, and a mirror is provided inside the lid 35.
As shown in FIG. 8, by opening the window lid 35 halfway and looking into the mirror inside the lid 35 from the front of the housing 30 (left side in FIG. 8), the vicinity of the sample table 38 inside can be observed through the window 34. .. Observing the semiconductor wafer 100 and the sensor head 60 through the window 34 has an advantage that it is easy to roughly adjust the vertical position and parallelism of the sensor head 60.

E. Modification Note that the present invention is not limited to the above embodiment,
The present invention can be implemented in various modes without departing from the spirit of the invention, and the following modifications are possible, for example.

(1) The external lead wire is not a wire-shaped wiring, but a holding member 70 made of a plurality of metal tab members 702 and a non-conductor as shown in FIG. 11A.
4 and a connector 700 having
May be electrically connected by contacting the wiring on the cone glass 66 (FIG. 4). 11
(B) is a sectional view showing a state in which the sensor head 60 is fixed to the connector 700. When the wiring of the sensor head 60 is formed on the side slope of the cone glass 66,
By pushing up the sensor head 60 from the lower side of the drawing with another supporting member, the sensor head 60 is moved to the connector 700.
And is electrically connected to the claw-shaped member 702. On the other hand, when the wiring of the sensor head 60 is formed on the peripheral surface of the cone glass 66, the tab 7
It is also possible to mechanically fix and electrically connect 02 by simply pressing 02 onto its peripheral surface.

(2) In the above-described embodiment, the dust-removed air is supplied to the housing by providing the air filter in the blower, but the dust-removed gas may be supplied by other gas supply means instead of the blower. .. For example, the gas may be blown out from a cylinder of air or nitrogen. However, a blower with a filter has an advantage of being inexpensive.

[0037]

As described above, in the non-contact electrical measuring device of the present invention, when the sample stage is located in the measuring chamber, the dust-free gas is discharged to the outside through the measuring chamber, the carry-in chamber and the exhaust chamber. Therefore, there is an effect that it is possible to reduce the intrusion of dust from the outside onto the semiconductor wafer. On the other hand, when the sample table moves to the carry-in chamber and the semiconductor wafer is carried in or out of the sample table, dust-removed air passes through the measurement chamber and the carry-in chamber and is released to the outside from the open lid. There is an effect that the invasion of dust onto the semiconductor wafer can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an outline of a semiconductor electrical measurement method.

FIG. 2 is a diagram showing a configuration of an electric measuring device as an embodiment of the present invention.

FIG. 3 is a diagram showing a bottom surface of an electrode forming portion and a BB cross section thereof.

FIG. 4 is a front view showing a connection state of wiring of the sensor head.

FIG. 5 is a perspective view showing a measuring unit and a vibration isolation table.

FIG. 6 is a graph showing various measurement results in the electric measuring device after the anti-vibration measures.

FIG. 7 is a cross-sectional side view of a main part of the measuring unit during measurement.

FIG. 8 is a cross-sectional plan view of an essential part of the measuring unit during measurement.

FIG. 9 is a cross-sectional side view of the main part of the measurement unit unit when a semiconductor wafer is loaded and unloaded.

FIG. 10 is a cross-sectional plan view of the main parts of the measurement unit unit when loading and unloading a semiconductor wafer.

FIG. 11 is a diagram showing a configuration of a connector of a sensor head.

[Explanation of symbols]

 20 Measuring Unit Unit 21 Vibration Isolating Table 22 Light Quantity Measuring Device 24 Impedance Meter 26 Position Control Device 28 Host Controller 30 Housing 32 Lid 34 Window 35 35 Lid 36 Frame 38 Sample Table 42 Flange 44 Piezoelectric Actuator 48 Support Plate 50 Support Tube 60 Sensor Head 62 Right-angled prism 64 Electrode forming part 66 Cone glass 70 Laser oscillator 72 Light receiving sensor 80 Pulse motor 90 Blower 100 Semiconductor wafer 111 Parallelism adjusting electrode 116 Lead wire 120 Guard ring 200 Electrode pattern 201 Electrical measurement electrode 510 Exhaust port 520 Sensor part 530 Sensor cover 540 Diffusion nozzle 610 Driving device 612 Ball screw part 620 Partition plate 622 Leg part 630 Linear guide 640 Exhaust port 700 Connector 702 Claw-shaped part 704 holding member ER exhaust chamber MR measuring chamber TR loading chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minoru Matsunaga, Minobu Matsunaga, 322 Hazushi, Furukawa-cho, Fushimi-ku, Kyoto Dainiichi Screen Manufacturing Co., Ltd. Rakusai Factory Address Dainichi Main Screen Manufacturing Co., Ltd. Rakusai Factory (72) Inventor Ikusho Nakatani 322 Hazashishi Furukawacho, Fushimi-ku, Kyoto City Dainichi Screen Manufacturing Co., Ltd. Rakusai Factory

Claims (1)

[Claims] 1. A non-contact electric measuring device for measuring electric characteristics of a semiconductor wafer in a non-contact manner, comprising: (a) a reflecting surface which is held substantially parallel to a surface of the semiconductor wafer with a gap therebetween. A transparent member having, and an electrode for electrical measurement formed adjacent to the reflecting surface, the gap of the gap based on the intensity of the laser light introduced into the transparent member and reflected by the reflecting surface. A sensor head for performing measurement and electrical characteristics of the semiconductor wafer using the electrical measurement electrode; (b) a movable sample stage on which the semiconductor wafer is mounted; (c) opening and closing A housing for accommodating the sensor head and the sample table with a possible lid, and a carry-in chamber for carrying in or carrying out a semiconductor wafer to the sample table when the sample table is located inside the lid, The carry-in room A housing provided with a measurement chamber that is in communication with the sensor head at the position of the sensor head and an exhaust chamber having an exhaust port; (d) gas supply means for supplying dust-removed gas to the measurement chamber; A partition plate that moves together with the sample table,
When the sample stage is located in the measurement chamber, the ventilation passage leading from the carry-in chamber to the exhaust chamber is opened, whereby
The gas supplied to the measurement chamber is guided to the exhaust chamber through the carry-in chamber to be released, while the gas passage is blocked when the semiconductor wafer is carried into or carried out from the sample stage located in the carry-in chamber. A partition plate for discharging the gas supplied to the measurement chamber to the outside through the carry-in chamber and the opened lid, thereby providing a non-contact electrical measurement device.