JPH11233603A - Method of detecting chucking force for electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with wafers of various kinds of materials by measuring the thermal wave value of a wafer irradiated with ions by the thermal wave method, and detecting the chucking force of an electrostatic chuck during the ion irradiation from a previously obtd. correlation with the measured value thereof. SOLUTION: The correlation of the wafer chucking force of an electrostatic chuck 100 under ion irradiation on a test wafer wf which is electrostatically chucked to a wafer support face of a holder 1 of the electrostatic chuck 100 to the thermal wave value of the test wafer wf, obtd. by the thermal wave method is obtd in advance. For executing the check and inspection work of the chucking force of electrostatic chuck 100, the thermal wave value of the wafer wf irradiated with the ions for ion implanting treatments is measured by the thermal wave method to detect the chucking force of the chuck 100 during the ion irradiation from this measured value and correlation obtained in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck for supporting a wafer called a wafer when performing ion irradiation for ion implantation or the like in the manufacture of a semiconductor device or the like. The present invention relates to detection of a wafer suction force by an electric chuck.

[0002]

2. Description of the Related Art In ion irradiation, for example, in the manufacture of semiconductor devices or the like, ion implantation is performed on a wafer for the purpose of reforming the wafer, or a film material is used to improve the adhesion of a film when forming a film on the wafer. It is used when ion irradiation is used in combination with vapor deposition. Such ion irradiation is usually performed by supporting a wafer on a wafer support holder in an ion implantation apparatus, a film forming apparatus, or the like. In this case, the wafer is held by the holder to prevent displacement. As such a holding means, for example, there is a mechanical means for placing a wafer on a wafer supporting surface of a holder and pressing the peripheral portion thereof to the holder with a ring-shaped pressing member. This electrostatic chuck has a wafer support holder to which an electrostatic chucking voltage can be applied, and a wafer supporting surface of the holder is applied by applying the electrostatic chucking voltage to the holder. The wafer can be electrostatically attracted. This electrostatic chuck has an advantage that generation of particles (fine dust) is sufficiently suppressed as compared with mechanical holding means using a pressing member or the like.

[0003] In the ion irradiation process, the wafer may be irradiated with ions by moving the wafer up and down together with a holder or tilting the wafer while rotating it. In such a case, in such an electrostatic chuck, if the chucking force of the electrostatic chuck is small, the inertia force accompanying the movement of the holder causes the wafer to shift from a predetermined suction position of the holder, or the ion irradiation angle to the wafer to shift. May be. Also, so-called particles that cause processing defects due to mutual contact between the wafer and the protrusions on the peripheral portion of the holder are likely to be generated, and the wafer may be damaged. In some cases, the wafer may even fall off the holder.

Therefore, in supporting the wafer by the electrostatic chuck, it is important that the wafer is accurately held at a predetermined suction position. Therefore, manufacturing of ion implantation equipment, etc.,
At the time of maintenance or in the manufacture of a semiconductor device or the like in such an ion implantation apparatus or the like, by detecting the chucking force of the electrostatic chuck, to confirm whether the electrostatic chuck exerts an appropriate electrostatic chucking force, If the electrostatic attraction force is not appropriate, appropriate measures must be taken.

[0005] As a method for detecting the attraction force of the electrostatic chuck, there is the following method. That is, a member for pulling up the wafer from the electrostatic chuck is bonded to the test wafer, the test wafer electrostatically attracted to the chuck is peeled off by the pulling member, and the force required at that time is measured by a load cell. And detecting the chucking force of the electrostatic chuck based on the measured value.

A gas blowing hole is provided in a wafer support holder of the electrostatic chuck, and a gas pressure is applied to the wafer electrostatically attracted to the holder from the holder hole to measure a pressure at which the wafer comes off the holder. A method of detecting the chucking force of the electrostatic chuck based on the measured value. Instead of measuring the electrostatic attraction force itself as in the method described above, a method for estimating the electrostatic attraction force by measuring data having a substantially constant relationship with the electrostatic attraction force is provided on the holder. Between the electrostatic capacity and the electrostatic attraction force between the electrostatic chucking electrode and the wafer (correlation obtained from the fact that the electrostatic capacity and the electrostatic attraction force depend on the distance between the wafer and the holder) ) Is determined in advance, and by measuring the capacitance between the wafer electrostatically attracted to the holder and the holder electrode, the chucking force of the electrostatic chuck is estimated from the relationship determined in advance.

The relationship between the electrostatic attraction current and the electrostatic attraction force flowing between the electrodes via the wafer by applying the electrostatic attraction voltage between the electrostatic attraction electrode pairs provided on the holder. Correlation obtained from the fact that the electrostatic chucking current and the electrostatic chucking force depend on the contact electric resistance between the wafer and the holder)
Is obtained in advance, and by measuring an electrostatic attraction current flowing through the wafer electrostatically attracted to the holder, the attraction force of the electrostatic chuck is estimated from the relationship determined in advance.

[0008]

However, the method for detecting the chucking force of the electrostatic chuck as described above has the following problems. That is, in the method described above, it is impossible to non-destructively measure the electrostatic attraction force acting on the wafer itself actually processed in the ion irradiation step.

In the above method, the capacitance between the wafer and the holder electrode is also affected by factors other than the distance between the wafer and the holder, for example, the surface roughness of the wafer. Between wafers having different elements, for example, elements having different surface roughness, etc., the capacitance may be different even when the same electrostatic chucking force is applied. It is difficult to accurately detect a state in which the electrostatic chucking force is out of the proper range and a state in which the electrostatic suction force is out of the appropriate range.

Further, in the method, when the electrostatic attraction force of a wafer having an insulating film such as an oxide film formed on the surface is detected, the contact electric resistance between the wafer and the holder is increased, and the holder flowing through the wafer is detected. This may cause a situation in which almost no electrostatic attraction current flows between the electrodes, and the electrostatic attraction force may not be detected. Therefore, the present invention is applicable to wafers of various materials including a wafer having an insulating film formed on its surface, and non-destructive electrostatic attraction acting on the wafer itself actually processed in the ion irradiation step. It is an object of the present invention to provide a method for detecting an electrostatic chuck chucking force which can be detected without applying a special operation.

[0011]

Means for Solving the Problems The inventor of the present invention has been studying to solve the above-mentioned problems, and has conducted electrostatic irradiation under ion irradiation on a wafer electrostatically attracted to a wafer supporting surface of a holder of an electrostatic chuck. Between the chucking force of the wafer by the chuck and the thermal wave value obtained by the thermal wave method for the wafer after ion irradiation, the wafer has the same condition (for example, the same type, the same size, etc.), and the ion irradiation condition If they are the same, they find that there is a certain correlation.

The present invention is based on this finding, and in order to solve the above-mentioned problems, there is provided a wafer support holder to which an electrostatic chucking voltage can be applied, and by applying the electrostatic chucking voltage to the holder. A method for detecting an electrostatic chucking force of an electrostatic chuck capable of chucking a wafer to a wafer support surface of the test device, wherein ion irradiation is performed on a test wafer electrostatically chucked to a wafer support surface of a holder of the electrostatic chuck. The correlation between the wafer chucking force by the electrostatic chuck and the thermal wave value obtained by the thermal wave method for the test wafer after ion irradiation is determined in advance, and the wafer is supported on the electrostatic chuck by the electrostatic chucking force. The thermal wave value of the ion-irradiated wafer after the ion irradiation was measured by the thermal wave method, and the measured value was correlated with the previously determined correlation. Providing an electrostatic chuck attraction force detecting method characterized by sensing the suction force of the electrostatic chuck at the time of ion irradiation from engagement.

Here, when determining the correlation between the wafer chucking force by the electrostatic chuck and the thermal wave value, the wafer chucking force may be the wafer chucking force itself, but the wafer chucking force is substantially determined. It may be another element represented, for example, a voltage for electrostatic attraction applied to the holder.
In the thermal wave method according to the present invention, the amount of damage (crystal distortion, crystal defect, etc.) applied to a wafer by ion irradiation in an ion implantation process, an etching process, a film formation process, or the like is determined in a non-contact, non-destructive manner. This method utilizes the fact that the amount of thermal vibration (thermal wave) generated by irradiating a laser beam to a wafer differs depending on the degree of damage to the wafer. Its applications are widely used in research and process management of semiconductor processes, such as monitoring of ion implantation amount, evaluation of strained layers in crystal substrate processing, measurement of dry etching damage, detection of crystal defects (dislocations and stacking faults). I have. Such a measurement is used, for example, as an apparatus utilizing a thermal wave method to evaluate the amount of ions applied to a wafer such as silicone in an ion irradiation process and the uniformity thereof.

As a specific operation example of the apparatus using the thermal wave method, there is, for example, a thermal wave measuring apparatus used for determining an operation of an ion implantation apparatus used in an ion implantation step in a semiconductor manufacturing process.
The thermal wave measuring apparatus is usually provided independently of the ion implantation apparatus at a ratio of one to several ion implantation apparatuses to check the operation of the entire ion implantation apparatus. That is, when a so-called pilot ion implantation process is periodically performed, the results of the thermal wave measurement performed by the device using the thermal wave method on the wafer after the ion implantation process indicate that the entire ion implantation process by the ion implantation device is normal. It is determined whether or not.

The present invention utilizes the measurement by the thermal wave method. Hereinafter, a method for detecting the electrostatic chuck chucking force according to the present invention will be described in detail. In the ion irradiation process, the wafer being subjected to the ion irradiation process, which is adsorbed and supported by the wafer support holder, is heated by receiving energy from the irradiated ions. Since the wafer is normally attracted and supported on the wafer support holder by the electrostatic chuck with a predetermined suction force, the wafer heat generated by the ion irradiation tends to escape from the wafer to the outside of the wafer via the support holder of the electrostatic chuck. However, as the chucking force of the electrostatic chuck on the wafer decreases, the thermal conductivity between the support holder and the wafer decreases, and the heat of the wafer hardly escapes outside the wafer. That is, as the chucking force of the electrostatic chuck decreases, the temperature of the wafer during ion irradiation tends to increase.

According to the study of the present invention, when a thermal wave value is measured by a thermal wave method for a wafer irradiated with ions as described above,
The thermal wave measurement value of the wafer whose temperature has risen tends to decrease as compared with the measurement value of the wafer whose temperature has not risen. The present inventor pays attention to the relationship of the wafer temperature to the electrostatic chuck chucking force during the ion irradiation and the relationship of the thermal wave value to the wafer temperature, under the same conditions (the same type, the same size, etc.) as the ion irradiation target wafer. ) The wafer chucking force by the electrostatic chuck under the ion irradiation of the target wafer under the same conditions as the ion irradiation of the test wafer, and the thermal wave value obtained by the thermal wave method for the wafer after the ion irradiation. Is determined in advance, and a thermal wave value of the wafer after ion irradiation is measured by the thermal wave method for the ion irradiation target wafer, and the electrostatic value at the time of ion irradiation is determined from the measured value and the correlation obtained in advance. A method for detecting the chucking force of the chuck has been found.

According to the electrostatic chuck chucking force detecting method of the present invention, it is possible to non-destructively detect the chucking force of the electrostatic chuck acting on the wafer itself actually processed in the ion irradiation step. In addition, since the measurement value obtained by the thermal wave method is used, it does not depend on the capacitance or contact electric resistance between the wafer and the wafer support holder. It can handle wafers of various materials including a wafer on which a film is formed. further,
In detecting the chucking force of the electrostatic chuck, it is not necessary to add a special operation such as venting a chamber (vacuum processing chamber) for performing an ion implantation process, a film formation process, and the like during the ion irradiation process.

According to this electrostatic chuck chucking force detecting method, for example, when this method is used for an ion implanter, it can also be used as a so-called pilot ion implantation process for confirming the movement of the entire ion implanter. The trouble of detecting the chucking force of the electric chuck can be reduced. In addition,
Applications of this electrostatic chuck chucking force detection method include adjusting, checking, and inspecting the chucking force of the electrostatic chuck during development, design, manufacture, and maintenance of ion implantation equipment, and ion implantation in the manufacture of semiconductor devices and the like. Inspection and inspection of the chucking force of an electrostatic chuck of an apparatus for manufacturing a semiconductor using the apparatus can be exemplified, but the present invention is not limited thereto.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a thermal wave measuring apparatus using a thermal wave method capable of implementing a method for detecting an electrostatic chuck chucking force according to the present invention, and FIG. 2 is conventionally used in an ion implantation apparatus. It is a figure showing the schematic section of an electrostatic chuck.

The electrostatic chuck 100 shown in FIG. 2 is provided in an ion implantation apparatus (not shown) in a part of the process of manufacturing a semiconductor device, and is provided with a wafer support holder 1 described later.
The electrostatic chuck 100 capable of electrostatically adsorbing a wafer wf to be described later on the wafer support surface includes a holder 1 made of a dielectric material, as shown in FIG. The plate-like electrodes 2 and 3 are buried slightly apart in an arrangement state as if they form a disk.
A voltage for electrostatic attraction can be applied to the electrodes 2 and 3 from the power supply PW.

Although not shown, the electrostatic chuck 100 is disposed in a vacuum processing chamber for performing an ion implantation process, and is used to support a wafer wf made of silicon, which is a processing object, here. The wafer wf supported by the electrostatic chuck 100 and implanted with ions in the ion implantation process of the ion implantation apparatus is placed on the wafer table 50 as shown in FIG. Is done. The thermal wave measuring device 200 is provided for the ion implantation step independently of the ion implantation device, and can measure the thermal wave value of the ion-implanted wafer wf to evaluate the ion implantation amount of the wafer wf and its uniformity. . The wafer wf of the electrostatic chuck 100 shown in FIG.
The adsorption force to the can be detected. This detection method will be described later in detail.

The thermal wave measuring apparatus 200 is not limited to this, but here, Thermo Wave
The pump laser unit 21 shown in FIG.
0, a probe laser section 220, a detection section 230, and the objective lens 14. In the thermal wave measuring device 200, an argon (AR) laser beam PN described later emitted from the pump laser unit 210 and a helium (He) -neon (Ne) laser beam PR described later emitted from the probe laser unit 220 are used as objects. A change in the reflectance of the He-Ne laser beam PR from the surface of the wafer wf, which is simultaneously irradiated on the same place of the wafer wf by the lens 14 and reflected on the surface of the wafer wf, can be detected by the detection unit 230.

The pump laser unit 210 is a light source for exciting the wafer wf and capable of irradiating the Ar laser light PN, an acousto-optic modulator 12 for modulating the laser light emitted from the laser 11, and Beam expander 13 for expanding the laser light modulated by modulator 12
It is composed of The probe laser unit 220 includes a He—Ne laser 15 that can emit a He—Ne laser beam PR as a probe laser, a beam expander 16 for expanding the laser beam emitted from the laser 15, and an expander 1.
6 is composed of a polarization splitter 17 that transmits light from 6 and reflects light from the opposite side, a He-Ne dichroic mirror 18 having the same light transmittance as the polarization splitter 17, and a λ / 4 wave plate 19.

The detecting section 230 includes a He-Ne filter 20 and a photodetector (detector) 21, and the objective lens 14 collects the Ar laser light PN and the He-Ne laser light PR at the same position on the wafer wf. Can be. According to the thermal wave measuring apparatus 200 having such a configuration, the laser light PN emitted from the Ar laser 11 in the direction a1 in the figure is modulated by the modulator 12 and the expander 13 respectively, expanded, and passed through the mirror 18 to the objective. Lens 14
Thus, the wafer wf is irradiated to a predetermined place. On the other hand, H
The laser beam PR emitted from the e-Ne laser 15 in the direction b1 in the figure is enlarged by the magnifier 16, passes through the polarization splitter 17, the plate 19, is reflected by the mirror 18 in the direction b2 in the figure, and is reflected by the objective lens 14. The laser beam PN of the wafer wf is irradiated to the same place as the place where the laser light PN is irradiated. Laser light PR reflected on the surface of wafer wf in b3 direction in the figure
Is reflected again by the mirror 18 in the b4 direction in the drawing,
The light is reflected by the polarization splitter 17 in the direction b3 in the figure through the plate 19, and further passes through the filter 20 to reach the photodetector 21. The photodetector 21 measures the change in the reflectivity of the laser beam PR reflected on the surface of the wafer wf on the wafer wf. The measurement of the change in reflectance will be described in more detail.

In this thermal wave measuring apparatus 200, the intensity of the laser beam PN emitted from the Ar laser 11 is periodically modulated by the modulator 12, so that the laser beam PN is applied to the silicone wafer wf. Plasma waves and heat waves (thermal waves) exist on the surface layer of the wafer wf due to carriers generated or annihilated in the wafer wf. These plasma waves and heat waves are
Since the dielectric constant of the silicone wafer wf is changed, He
The laser beam PR emitted from the -Ne laser 15 contributes to a change in reflectance at the wafer wf. At this time, if there is damage such as lattice defects in the silicone wafer wf,
The reflectance of the He—Ne laser beam PR changes according to the damage amount.

Therefore, when the change in the reflectivity of the He—Ne laser beam PR is accurately measured, the amount of damage applied to the wafer wf can be accurately detected. As a result, the wafer w is formed by the ion implantation process of the ion implantation apparatus.
The amount of ions implanted into f and its uniformity can be evaluated. The He—Ne laser light PR as the probe laser light is measured as a waveform of a change rate ΔR with respect to the reflectance R by the Ar laser light PN as the modulated pump laser light, and for convenience, 1 TW unit = 10 ^6. It is expressed as T / R as ΔR / R.

Next, a method for detecting the electrostatic chuck chucking force according to the present invention will be described. In order to carry out the method for detecting the electrostatic chuck chucking force, the electrostatic chuck 1 shown in FIG.
Between the wafer chucking force of the electrostatic chuck 100 and the thermal wave value obtained by the thermal wave measuring device 200 for the test wafer after the ion irradiation under the ion irradiation on the test wafer wf adsorbed to the holder 1 of FIG. The correlation was determined in advance. In obtaining this correlation, the test wafer was a wafer wf under the same conditions as the ion irradiation target wafer wf, and the ion irradiation was performed under the same conditions as the ion irradiation conditions on the ion irradiation target wafer wf. That is, here, the following conditions are satisfied.

Wafer: size 200 mm in diameter, 0.75 mm in thickness Ion irradiation: ion species Boron ion (B ⁺ ) Irradiation energy 100 KeV Irradiation time 200 seconds FIG. 3 is applied to the holder 1 of the electrostatic chuck by the power supply PW shown in FIG. The relationship between the applied voltage for electrostatic attraction and the temperature of the wafer during ion irradiation is shown. It should be noted that the electrostatic attraction voltage determines the electrostatic attraction force thereby, and can be said to indirectly represent the electrostatic attraction force.

FIG. 4 shows the relationship between the temperature rise of the wafer during ion irradiation and the measured value of the thermal wave of the wafer after ion irradiation. As shown in FIG. 3, when the electrostatic chucking voltage (in other words, the electrostatic chucking force) increases, the heat generated by the wafer easily escapes to the holder 1 and the wafer temperature becomes relatively low. When (in other words, the electrostatic attraction force) decreases, the wafer tends to separate from the holder 1, so that it becomes difficult for the wafer heat to escape to the holder 1, and the wafer temperature increases accordingly. The temperature of the wafer during ion irradiation was measured using a plurality of thermochromic labels having different discoloration points depending on the attained temperature.

FIG. 4 shows that when the wafer temperature during ion irradiation is high, the measured value of the thermal wave by the thermal wave measuring apparatus shown in FIG. 1 is low, and when the wafer temperature during ion irradiation is low, the measured thermal wave value is small. Indicates that it becomes larger. That is, FIG. 4 shows that there is a correlation between the wafer heating temperature during ion irradiation and the thermal wave measurement value.

From the correlations shown in FIGS. 3 and 4, a correlation between the voltage for electrostatic attraction (in other words, the electrostatic attraction force) and the measured value of the thermal wave can be derived, and FIG. 5 shows such a relationship. 2 shows the relationship between the voltage for electrostatic adsorption and the measured value of the thermal wave after ion irradiation. The relationship shown in FIG. 5 was obtained as follows. That is, the temperature of the wafer (approximately 30 ° C.) with respect to the thermal wave value (approximately 1810 TW unit) of point A1 in FIG.
The electrostatic attraction voltage (approximately 300 V: point B1 in FIG. 4) with respect to the wafer temperature (approximately 30 ° C.) obtained in FIG.
The temperatures (approximately 30 ° C.) and the electrostatic chucking voltages (approximately 300 V) of these wafers were plotted at a point C1 in FIG. Similarly, for points C2 and C3 in FIG. 5, points A2 and C3 in FIG.
Each value obtained from A3 and points B2 and B3 in FIG. 3 was plotted.

In this way, the value between the electrostatic attraction voltage and the thermal wave value was obtained as shown in FIG. FIG. 6 shows the relationship between the electrostatic attraction voltage and the electrostatic attraction force.
In this case, the electrostatic attraction force was measured using only the spring attached to the wafer and its vertical lifting mechanism.

Next, the relationship between the electrostatic attraction force and the thermal wave value was determined from the respective correlations shown in FIGS.
FIG. 7 is a diagram showing the relationship. The relationship shown in FIG. 7 was obtained as follows. That is, for example, the electrostatic attraction voltage (approximately 300 V) for the thermal wave value (approximately 1810 TW unit) at the point C1 in FIG. 5 is obtained, and the electrostatic attraction voltage (approximately 300 V) obtained from FIGS. The force (approximately 130 Kgw: point D1 in FIG. 6) was obtained, and these thermal wave values (approximately 1810 TW units) and the electrostatic attraction force (approximately 130 Kgw) were plotted at a point E1 in FIG.
As for the points E2 and E3 in FIG.
The respective values obtained from points C2 and C3 in FIG. 5 and points D2 and D3 in FIG. 6 are plotted.

Thus, a constant correlation between the electrostatic attraction force and the thermal wave value was obtained as shown in FIG. In the manufacture of semiconductor devices, when inspecting and inspecting the chucking force of the electrostatic chuck of the ion implantation apparatus, the thermal wave value of the wafer after the irradiation of the ions in the ion implantation processing is measured by the thermal wave measurement apparatus 200. 7, the attraction force (point X in FIG. 7: approximately 90 kgw) of the electrostatic chuck 100 at the time of ion irradiation can be detected from the correlation shown in FIG. 7 with the measured value (eg, 1790 TW unit). It is sufficient that this value is within the proper range of the electrostatic chucking force. If the value is out of the proper range, an appropriate treatment may be performed on the electrostatic chuck 100. For example, the voltage for electrostatic attraction may be adjusted.

The method of detecting the chucking force of the electrostatic chuck here is to determine the chucking force of the electrostatic chuck 100 from the correlation between the thermal wave value and FIG. 7, but as shown in FIG. Since the electro attraction voltage and the electrostatic chucking force are in a proportional relationship, the chucking voltage of the electrostatic chuck 100 is obtained from the correlation shown in FIG. 5 instead of the correlation between the thermal wave value and the electrostatic chucking force itself. The attraction force may be detected by the electroadsorption voltage.

According to the electrostatic chuck chucking force detecting method of the present invention, it is possible to non-destructively detect the chucking force of the electrostatic chuck acting on the wafer itself actually processed in the ion irradiation step. In addition, since the measurement value by the thermal wave method is used, an insulating film such as an oxide film is formed on wafers or surfaces having different surface roughnesses without depending on the capacitance and contact electric resistance between the wafer and the wafer support holder. It can handle wafers of various materials including formed wafers. Further, in detecting the chucking force of the electrostatic chuck, it is not necessary to perform a special operation such as venting a vacuum processing chamber (not shown) for performing ion implantation during ion irradiation.

Further, according to the electrostatic chuck chucking force detecting method, the operation of the whole apparatus for manufacturing a semiconductor using the ion implanter can be confirmed, that is, a so-called pilot ion implantation process can be used. The trouble of detecting is reduced. The method for detecting the chucking force of the electrostatic chuck here is used for checking and inspecting the chucking force of the electrostatic chuck of the ion implanter in the manufacture of the semiconductor device, but is not limited to this. It can be used for adjustment, inspection, inspection work, etc. of the chucking force of the electrostatic chuck during development, design, manufacturing, and maintenance. The electrostatic chuck shown in FIG. 7 can be applied to various devices.

[0038]

As described above, according to the present invention, it is possible to cope with wafers of various materials including a wafer having an insulating film formed on the surface thereof, and electrostatic adsorption acting on the wafer itself actually processed in the ion irradiation step. It is possible to provide an electrostatic chuck chucking force detecting method capable of detecting the chucking force of the electrostatic chuck without destructing the force and without applying a special operation to the ion implantation apparatus or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a thermal wave measuring apparatus using a thermal wave method for implementing a method for detecting an electrostatic chuck chucking force according to the present invention.

FIG. 2 is a schematic sectional view of an electrostatic chuck.

FIG. 3 is a diagram showing a relationship between an electrostatic chucking voltage and a wafer temperature.

FIG. 4 is a diagram showing a relationship between a temperature of a wafer during ion irradiation and a thermal wave value.

FIG. 5 is a diagram illustrating a relationship between an electrostatic chucking voltage and a thermal wave value.

FIG. 6 is a diagram showing a relationship between an electrostatic attraction force and an electrostatic attraction voltage.

FIG. 7 is a diagram showing a relationship between an electrostatic attraction force and a thermal wave value.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 electrostatic chuck 1 holder 2, 3 electrode PW power supply wf wafer 200 thermal wave measuring device 210 pump laser unit 220 probe laser unit 230 detection unit 230 PN pump laser light PR probe laser light 11 Ar laser 12 acousto-optic modulator 13 16 beam Magnifier 14 Objective lens 15 He-Ne laser 17 Polarization splitter 18 He-Ne dichroic mirror 19 λ / 4 wave plate 20 He-Ne filter 21 Photodetector (detector) 50 Wafer table

Claims (1)

[Claims] 1. An electrostatic chuck for an electrostatic chuck having a wafer support holder to which an electrostatic chucking voltage can be applied and applying a electrostatic chucking voltage to the holder to hold a wafer on a wafer supporting surface of the holder. A method for detecting a force, wherein a wafer chucking force by the electrostatic chuck under ion irradiation on a test wafer electrostatically attracted to a wafer support surface of a holder of the electrostatic chuck and the test after ion irradiation. The correlation between the wafer and the thermal wave value obtained by the thermal wave method is determined in advance, and the thermal irradiation of the wafer after ion irradiation to the ion irradiation target wafer supported by the electrostatic chuck with electrostatic attraction force is performed. The wave value is measured by the thermal wave method, and the attraction force of the electrostatic chuck at the time of ion irradiation is detected from the measured value and the correlation obtained in advance. The electrostatic chuck attraction force detection method according to.