KR20200045672A - Chucking force holding apparatus for an electrostatic chuck, and electrostatic chuck device having the same - Google Patents

Abstract

The present invention, as a technique for maintaining a constant chucking force to a wafer despite the thickness change of a dielectric covering a surface of an electrostatic chuck in the electrostatic chuck gripping the wafer, relates to a technique for maintaining the chucking force of the electrostatic chuck in the process of the wafer frequently rising and falling with respect to a top surface of the electrostatic chuck, and an original wafer is adjusted by adjusting a DC voltage applied to the dielectric in response to the changing thickness of the dielectric. According to the present invention, as a capacitive measurement module, a thickness estimation unit, and a DC voltage control module are separately provided, it can be applied to the existing electrostatic chuck assembly.

Description

Chucking force holding apparatus for an electrostatic chuck, and electrostatic chuck device having the same}

The present invention relates to a technique for maintaining a constant chucking force to the wafer despite the thickness change of the dielectric covering the surface of the electrostatic chuck in the electrostatic chuck gripping the wafer.

More specifically, the present invention changes the thickness due to wear of the dielectric covering the surface of the electrostatic chuck in a process in which the wafer frequently rises and falls with respect to the upper surface of the electrostatic chuck, which is applied to the dielectric in response to the changing thickness of the dielectric. It relates to a technique for maintaining the chucking force of the electrostatic chuck with respect to the original wafer by adjusting the DC voltage.

1 is an exemplary view showing an installation state of an electrostatic chuck according to the prior art. Referring to FIG. 1, in general, an electrostatic chuck (ESC) assembly 20 is mounted on the inside of the process chamber 40 and is charged on its upper surface as it is charged to generate electrostatic force on its upper surface. The wafer 10 to be seated is held as it is.

Then, the upper surface of the electrostatic chuck assembly 20 directly contacting the wafer 10 is covered with a so-called dielectric to generate electrostatic force through the DC voltage supply unit 30 supplied from the outside. As a result, the electrostatic chuck assembly 20 is capable of holding the wafer 10 located on its upper surface by the electrostatic force.

As described above, as the wafer 10 is seated on the upper surface of the electrostatic chuck assembly 20, the wafer 10 is exposed to the plasma supplied from the shower head 50, thereby processing the original processing process of the wafer 10. Will go through.

Here, since the electrostatic chuck assembly 20 is movable in a state in which the wafer 10 is mounted on its upper surface, so that the left and right horizontally incline in the process, the electrostatic chuck assembly 20 is predetermined to grip the wafer 10. It is necessary to keep the chucking force constant.

At this time, the upper surface of the electrostatic chuck assembly 20 in contact with the lower surface of the wafer 10 is made of a so-called dielectric. Since the dielectric has a predetermined thickness, when the thickness of the dielectric is slightly changed, the chucking force exhibited by the electrostatic chuck assembly 20 is held to hold the wafer 10.

However, the dielectric of the upper surface of the electrostatic chuck assembly 20 cannot be avoided because its thickness changes as it is worn due to frequent friction with the wafer 10 that moves up and down its upper surface.

In addition, because the chucking force of the electrostatic chuck assembly 20 with respect to the wafer 10 cannot be accurately measured, the thickness variation of the dielectric cannot be accurately measured. It is impossible to give.

Accordingly, by estimating the thickness change of the dielectric that changes according to the life time of the electrostatic chuck and applying the electrostatic force corresponding to the estimated value, the chucking force of the electrostatic chuck with respect to the wafer is maintained, thereby solving the problems of the prior art as described above. A technique that can be solved is desired.

The present invention has been proposed in view of the above, the object of the present invention is to estimate the thickness change of the dielectric located on the upper surface of the electrostatic chuck and to set the adjusted electrostatic force according to the estimated value to determine the chucking force for the wafer. It is to provide a chucking force maintaining device of an electrostatic chuck that can be maintained as it is and an electrostatic chuck device having the same.

In order to achieve the above object, the present invention is integrally connected to the chuck body, the upper surface of the chuck body, and a dielectric body for mounting the wafer on its upper surface by electrostatic force, and mounted inside the chuck body, the chuck body for the wafer A device for maintaining the chucking force of an electrostatic chuck having a fixed electrode for charging a chuck body for a chucking force and a DC power supply unit for supplying DC power to the fixed electrode. Capacitance measurement module for measuring; A thickness estimation unit for estimating the thickness of the dielectric based on the capacitance measured by the capacitance measurement module; It comprises a; DC voltage control module for setting the DC voltage of the DC power supply unit for the fixed electrode in response to the estimated thickness of the dielectric to maintain the chucking force of the fixed electrode.

At this time, the capacitive measurement module according to the first embodiment of the present invention, as a conductor probe connected to the upper surface of the dielectric, a first electrode terminal in charge of any one of the (+) electrode and (-) electrode; A second electrode terminal connected to a lower portion of the chuck body and in charge of an electrode opposite to the first electrode terminal among the (+) and (-) electrodes; It can be configured to include; a first electrode terminal and the second electrode terminal is energized to measure the electric capacity between the first electrode terminal and the second electrode terminal.

In addition, the capacitive measurement module according to the second embodiment of the present invention, a test-only wafer mounted on the upper surface of the dielectric; A third electrode terminal connected to the upper surface of the test wafer and in charge of one of the (+) electrode and the (-) electrode; A fourth electrode terminal connected to a lower portion of the chuck body and in charge of an opposite electrode to the third electrode terminal among the (+) and (-) electrodes; It may be configured to include; a capacitance measurement unit for measuring the electric capacity between the third electrode terminal and the fourth electrode terminal is energized to the third electrode terminal and the fourth electrode terminal.

In addition, the capacitive measurement module according to the third embodiment of the present invention, a fifth electrode terminal connected to one of the (+) electrode and (-) electrode of the fixed electrode; A sixth electrode terminal connected to the fifth electrode terminal and the other of the (+) and (-) electrodes of the fixed electrode; It may be configured to include; a capacitance measurement unit that is energized to the fifth electrode terminal and the sixth electrode terminal to measure the electric capacity between the fifth electrode terminal and the sixth electrode terminal.

On the other hand, the electrostatic chuck device having a chucking force maintaining device according to the present invention, the chuck body; A dielectric body integrally connected to the upper surface of the chuck body and seating the wafer on its upper surface by electrostatic force; A fixed electrode mounted inside the chuck body to charge the chuck body for the chucking force of the chuck body against the wafer; A DC power supply unit that supplies DC power to the fixed electrode; Capacitance measurement module for measuring the capacitance changing according to the thickness of the dielectric; A thickness estimation unit for estimating the thickness of the dielectric based on the capacitance measured by the capacitance measurement module; It may be configured to include; a DC voltage control module for setting the DC voltage of the DC power supply unit for the fixed electrode in response to the estimated thickness of the dielectric to maintain the chucking force of the fixed electrode.

The present invention shows the advantage of accurately estimating the thickness of the dielectric in response to the changing capacitance as monitoring the capacitance values of the dielectric and the chuck body.

In addition, the present invention shows the advantage of maintaining the original chucking force applied to the dielectric and the chuck body by controlling the DC voltage applied to the dielectric and the chuck body in response to the thickness of the dielectric previously estimated.

In addition, the present invention shows an advantage that can be applied to the existing electrostatic chuck assembly as it is provided with a separate capacitive measurement module, thickness estimation unit, DC voltage control module.

1 is an exemplary view showing the installation state of the electrostatic chuck according to the prior art,
Figure 2 is an exemplary view conceptually showing the generation of electrostatic force according to the DC power supply,
Figure 3 is an exemplary view conceptually showing the generation of electrostatic force due to the DC power supply 2,
4 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to a first embodiment of the present invention,
5 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to a second embodiment of the present invention,
6 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to a third embodiment of the present invention.

FIG. 2 is an exemplary view conceptually showing the generation of electrostatic force due to DC power supply, and FIG. 3 is an exemplary view 2 conceptually showing the generation of electrostatic force due to DC power supply.

First, referring to FIG. 2, when an insulator having a predetermined dielectric constant (ε ₁ ) is disposed between metal plates that are charged with (+) and (-), and when DC voltage is applied, the insulators between the metal plates are ①. It can represent the electric capacity (C) as in the equation.

At this time, the insulator may exhibit an electrostatic force (F), such as ②. Here, the expression (2) can be expressed as the expression (3) by arranging it based on 'V'.

And, referring to [Fig. 3], when applying the DC voltage to charge the upper and lower surfaces of the 'electrostatic chuck' having a predetermined dielectric constant (ε ₂ ) with (+) and (-) respectively, the electrostatic chuck is expressed in ④ expression. It can represent the electric capacity (C).

At this time, the electrostatic chuck may exhibit a chucking force (F) such as ⑤. Here, ⑤ expression can be expressed as ⑥ by arranging it based on 'V'.

Here, when the thickness of the electrostatic chuck of [FIG. 3] becomes thin, the chucking force F increases according to ⑤ expression. When the chucking force (F) is raised as described above, a problem in processing of the wafer seated on the upper surface of the electrostatic chuck may occur.

As a result, as the thickness of the electrostatic chuck in FIG. 3 becomes thin, when the chucking force F rises, it is necessary to lower the chucking force to the original chucking force.

To do this, since 'V' and 'F' are proportional in equation ⑥, if the DC voltage (V) that charges the upper and lower surfaces of the 'electrostatic chuck' with (+) and (-) respectively is low, the chucking force (F) ).

At this time, since it is necessary to determine how much the DC voltage V should be lowered, a specific configuration for this is necessary. Hereinafter, the present invention for this will be described in detail with reference to the drawings.

4 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to the first embodiment of the present invention.

4, the chucking force holding device according to the first embodiment of the present invention is integrally connected to the chuck body 110 and the upper surface of the chuck body 110, and the wafer is placed on its upper surface by electrostatic force. A dielectric 120 for seating, a fixed electrode 130 mounted on the inside of the chuck body 110 to charge the chuck body 110 for chucking force of the chuck body 110 to the wafer, and a fixed electrode ( Capacitance measurement module 210, thickness estimation unit 220, DC voltage control module 230 to maintain the chucking force for the electrostatic chuck having a DC power supply unit 140 for supplying DC power to 130) It may be configured to include.

Here, the capacitance measurement module 210 is the first electrode terminal 212, the second electrode terminal 214, the capacitance measurement unit 216 to measure the capacitance changing according to the thickness change of the dielectric 120 It may be configured to include.

The first electrode terminal 212 is connected to the upper surface of the dielectric 120 as shown in [Fig. 4] and is in charge of any one of the (+) electrode and the (-) electrode, preferably a robot arm (not shown) It may be composed of a conductor probe (not shown) that can be moved by.

To this end, the first electrode terminal 212 may be configured to enter and exit the inside and outside of the process chamber 150 through the access member 151 provided on the side wall of the process chamber 150. At this time, the first electrode terminal 212 may move inside and outside of the access member 151 while being gripped by the robot arm as a conductor probe.

The second electrode terminal 214 is connected to the lower portion of the chuck body 110 as shown in [FIG. 4] and is responsible for one electrode different from the first electrode terminal 212 among the (+) electrode and the (-) electrode. It is composed.

The capacitance measurement unit 216 is configured to measure the capacitance between the first electrode terminal 212 and the second electrode terminal 214 by being energized to the first electrode terminal 212 and the second electrode terminal 214. You can.

The thickness estimating unit 220 estimates the thickness of the dielectric 120 based on the capacitance measured by the capacitance measurement module 210 as shown in FIG. 4.

Since the dielectric 120 is integrally connected to the chuck body 110 on the upper surface of the chuck body 110, even when the thickness of the dielectric 120 is changed due to abrasion or the like, the changed thickness of the dielectric 120 can be measured. There is no.

As a result, the current dielectric according to the thickness change of the dielectric 120 is monitored by monitoring the electric capacity by charging the (+) electrode and the (-) electrode to the upper surface of the dielectric 120 and the lower end of the chuck body 110. (120) The thickness can be estimated.

By applying the DC voltage according to the estimated thickness of the dielectric 120, it is possible to maintain the original chucking force.

The DC voltage control module 230 sets the DC voltage of the DC power supply unit 140 for the fixed electrode 130 in response to the estimated thickness of the dielectric 120 to maintain the chucking force of the fixed electrode 130. .

For example, when the capacitance C is known through the capacitance measurement module 210, the DC voltage control module 230 maintains the original constant chucking force F in accordance with the expression ⑧ of [FIG. 3] ( It is possible to calculate the DC voltage (V) to be applied to 110).

At this time, according to the expression ⑧ in [Figure 3], the DC voltage control module 230 also knows the 'D' value to calculate the DC voltage (V) to be applied to the chuck body 110, which is a thickness estimation unit. (220) This can be estimated the 'D' value according to the formula (5) of [Fig. 3].

Here, since the 'A' value of [Figure 3] is a constant value corresponding to the width of the chuck body 110, the 'D' value is automatically estimated if only the electric capacity C is known according to [Figure 3]. You can.

On the other hand, 'F' in [Fig. 3] also shows the same meaning as the chucking force as an electrostatic force, and since the optimum value for chucking the original wafer is determined, the 'F' value is already known and the 'C' value is known. When the 'D' value can be estimated, as a result, the DC voltage control module 230 controls the DC power supply unit 140 according to the expression ⑧ of [FIG. 3] so that the DC power supply unit 140 is a chuck body. It is possible to determine the DC voltage (V) to be applied to (110).

On the other hand, the electrostatic chuck device having the chucking force maintaining device according to the first embodiment of the present invention, the capacitive measurement module 210, thickness measurement unit 220, DC voltage control of [Fig. It comprises a module 230.

And, the electrostatic chuck device having a chucking force maintaining device according to the first embodiment of the present invention, as shown in [Fig. 4], the chuck body 110, dielectric 120, fixed electrode 130, DC power supply It may be configured to further include a unit 140.

The chuck body 110 may be configured in the form of a flat plate with its upper surface as shown in FIG. 4 so that the wafer can be chucked while the wafer is mounted on its upper surface.

Dielectric 120 is integrally connected to the upper surface of the chuck body 110 as shown in [Fig. 4] and seats the wafer on its upper surface by electrostatic force.

That is, the dielectric 120 generates an electrostatic force with respect to the wafer positioned on its upper surface by being charged through the fixed electrode 130. As a result, it chucks (holds) the wafer located on its top surface through its own electrostatic force.

At this time, the dielectric 120 is charged with an electrode opposite to the electrode represented by the fixed electrode 130 in a state adjacent to the fixed electrode 130.

The fixed electrode 130 is mounted on the inside of the chuck body 110, as shown in [Figure 4], the chuck body 110 for the chucking force of the chuck body 110 with respect to the wafer (+) electrode and ( -) Charge with an electrode.

The fixed electrode 130 is preferably disposed wide in correspondence with the width of the chuck body 110 on the inner upper portion of the chuck body 110 as shown in FIG. 4.

To this end, the DC power supply unit 140 applies a DC voltage to the fixed electrode 130 while being energized to the fixed electrode 130.

In addition, the electrostatic chuck device having the chucking force maintaining device according to the first embodiment of the present invention may be configured to further include a process chamber 150 and a shower head 160 as shown in FIG. 4.

The process chamber 150 arranges a chuck body 110 for chucking the wafer on its inner side. In addition, the process chamber 150 provides an external and closed space so that the plasma irradiated from the shower head 160 disposed on its upper part responds smoothly to the wafer chucked on the upper surface of the chuck body 110.

The shower head 160 generates a plasma for processing a wafer on the chuck body 110 in its downward direction while being disposed on the upper portion of the process chamber 150 as shown in FIG. 4.

Here, a detailed description of the process of generating the plasma by the shower head 160 and a separate power supply means for supplying power to the shower head 160 for generating the plasma is omitted.

5 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to a second embodiment of the present invention.

5, the chucking force maintaining device according to the second embodiment of the present invention is integrally connected to the chuck body 110 and the upper surface of the chuck body 110, and the wafer is placed on its upper surface by electrostatic force. A dielectric 120 for seating, a fixed electrode 130 mounted on the inside of the chuck body 110 to charge the chuck body 110 for chucking force of the chuck body 110 to the wafer, and a fixed electrode ( Capacitance measurement module 210, thickness estimation unit 220, DC voltage control module 230 to maintain the chucking force for the electrostatic chuck having a DC power supply unit 140 for supplying DC power to 130) It may be configured to include.

Here, the capacitive measurement module 210 is a test-only wafer 211, a third electrode terminal 213, a fourth electrode terminal 215, in order to measure the changing capacitance according to the thickness of the dielectric 120, It may be configured to include a capacitance measurement unit 217.

The test-only wafer 211 is formed in the same specification as the process wafer, and is used only for test purposes, and may be configured to be seated on the upper surface of the dielectric 120 as shown in FIG. 5.

The test-only wafer 211 may be patterned with a wire for conduction on its surface so that when the third electrode terminal 213 is connected to its upper surface, the third electrode terminal 213 is electrically energized.

The test wafer 211 may be configured to enter and exit the inside and outside of the process chamber 150 through the access member 151 provided on the side wall of the process chamber 150. At this time, the test-only wafer 211 may move inside and outside of the access member 151 while being gripped by the robot arm.

The third electrode terminal 213 is connected to the upper surface of the test-only wafer 211 as shown in [FIG. 5] and is in charge of any one of the (+) electrode and the (-) electrode. At this time, the third electrode terminal 213 may be preferably composed of a conductor probe (not shown) movable by a robot arm (not shown).

To this end, the third electrode terminal 213 may be configured to enter and exit the inside and outside of the process chamber 150 through the access member 151 provided on the side wall of the process chamber 150. At this time, the third electrode terminal 213 may move inside and outside of the access member 151 while being gripped by the robot arm as a conductor probe.

Meanwhile, the wafer 212 for testing and the third electrode terminal 213 may be mounted in a separate housing (not shown) provided on the side of the process chamber 150 so as to pass through the access member 151. The test-only wafer 212 and the third electrode terminal 213 mounted in the housing may move inside and outside of the access member 151 through a robot arm.

On the other hand, the third electrode terminal 213 may be provided to be wirelessly configured to transmit and receive signals to and from the test-only wafer 211 while being spaced apart from the test-only wafer 211. In this case, it is preferable to have an antenna for wireless communication inside the test-only wafer 211.

The fourth electrode terminal 215 is connected to the lower portion of the chuck body 110 as shown in [FIG. 5], and is responsible for an electrode opposite to the third electrode terminal 213 among the (+) electrode and the (-) electrode. Can be configured.

The capacitance measurement unit 217 is configured to measure the capacitance between the third electrode terminal 213 and the fourth electrode terminal 215 by being energized to the third electrode terminal 213 and the fourth electrode terminal 215. You can.

In the second embodiment of the present invention, the thickness estimating unit 220 is configured to estimate the thickness of the dielectric 120 based on the capacitance measured by the capacitance measuring module 210 as shown in FIG. 5.

Since the dielectric 120 is integrally connected to the chuck body 110 on the upper surface of the chuck body 110, even when the thickness of the dielectric 120 is changed due to abrasion or the like, the changed thickness of the dielectric 120 can be measured. There is no.

As a result, the electric capacity by charging the (+) electrode and the (-) electrode on the upper surface of the test-only wafer 211 and the lower end of the chuck body 110 is monitored to change the thickness of the dielectric 120. The thickness of the dielectric 120 can be estimated.

By applying the DC voltage according to the estimated thickness of the dielectric 120, it is possible to maintain the original chucking force.

The DC voltage control module 230 sets the DC voltage of the DC power supply unit 140 for the fixed electrode 130 in response to the estimated thickness of the dielectric 120 to maintain the chucking force of the fixed electrode 130. .

For example, when the capacitance C is known through the capacitance measurement module 210, the DC voltage control module 230 maintains the original constant chucking force F in accordance with the expression ⑧ of [FIG. 3] ( It is possible to calculate the DC voltage (V) to be applied to 110).

At this time, according to the expression ⑧ in [Figure 3], the DC voltage control module 230 also knows the 'D' value to calculate the DC voltage (V) to be applied to the chuck body 110, which is a thickness estimation unit. (220) This can be estimated the 'D' value according to the formula (5) of [Fig. 3].

Here, since the 'A' value of [Figure 3] is a constant value corresponding to the width of the chuck body 110, the 'D' value is automatically estimated if only the electric capacity C is known according to [Figure 3]. You can.

On the other hand, 'F' in [Fig. 3] also shows the same meaning as the chucking force as an electrostatic force, and since the optimum value for chucking the original wafer is determined, the 'F' value is already known and the 'C' value is known. When the 'D' value can be estimated, as a result, the DC voltage control module 230 controls the DC power supply unit 140 according to the expression ⑧ of [FIG. 3] so that the DC power supply unit 140 is a chuck body. It is possible to determine the DC voltage (V) to be applied to (110).

On the other hand, the electrostatic chuck device having the chucking force maintaining device according to the second embodiment of the present invention, the capacitance measurement module 210, thickness measurement unit 220, DC voltage control of [Fig. It comprises a module 230.

And, the electrostatic chuck device having a chucking force maintaining device according to the second embodiment of the present invention, as shown in [Fig. 5], the chuck body 110, dielectric 120, fixed electrode 130, DC power supply It may be configured to further include a unit 140.

Since the chuck body 110, the dielectric 120, the fixed electrode 130, and the DC power supply unit 140 according to the second embodiment of the present invention are the same as the first embodiment of the present invention, detailed description thereof is omitted. do.

In addition, the electrostatic chuck device having the chucking force maintaining device according to the second embodiment of the present invention may be configured to further include a process chamber 150 and a shower head 160 as shown in FIG. 5.

Here, since the process chamber 150 and the shower head 160 according to the second embodiment of the present invention are the same as the first embodiment of the present invention, detailed descriptions thereof will be omitted.

6 is an exemplary view of an apparatus for maintaining a chucking force of an electrostatic chuck and an electrostatic chuck device having the same according to a third embodiment of the present invention.

Referring to FIG. 6, the chucking force holding device according to the third embodiment of the present invention is integrally connected to the chuck body 110 and the upper surface of the chuck body 110 and places the wafer on its upper surface by electrostatic force. A dielectric 120 for seating, a fixed electrode 130 mounted on the inside of the chuck body 110 to charge the chuck body 110 for chucking force of the chuck body 110 to the wafer, and a fixed electrode ( Capacitance measurement module 210, thickness estimation unit 220, DC voltage control module 230 to maintain the chucking force for the electrostatic chuck having a DC power supply unit 140 for supplying DC power to 130) It may be configured to include.

Here, the capacitance measurement module 210 is a fifth electrode terminal 213 ', a sixth electrode terminal 215', a capacitance measurement unit (to measure the capacitance changing according to the thickness change of the dielectric 120) 217 ').

The fifth electrode terminal 213 'is connected to one of the (+) electrode and the (-) electrode of the fixed electrode 130 as shown in [Fig. 6], and the sixth electrode terminal 215' is [Fig. 6], the fifth electrode terminal 213 'of the (+) electrode and the (-) electrode of the fixed electrode 130 may be connected to another electrode.

As shown in the third embodiment of the present invention, the fifth electrode terminal 213 'and the sixth electrode terminal 215' are connected to the fixed electrode 130, respectively, and the capacitance measured according to the thickness change of the dielectric 120 As the changes in the DB are continuously monitored, the thickness change of the dielectric 120 can be estimated based on the measured electric capacity.

The capacitance measurement unit 217 'is energized to the fifth electrode terminal 213' and the sixth electrode terminal 215 ', and the capacitance between the fifth electrode terminal 213' and the sixth electrode terminal 215 '. It can be configured to measure.

In the third embodiment of the present invention, the thickness estimating unit 220 is configured to estimate the thickness of the dielectric 120 based on the capacitance measured by the capacitance measuring module 210 as shown in FIG. 6.

Since the dielectric 120 is integrally connected to the chuck body 110 on the upper surface of the chuck body 110, even when the thickness of the dielectric 120 is changed due to abrasion or the like, the changed thickness of the dielectric 120 can be measured. There is no.

As a result, it is possible to maintain the original chucking force by applying the DC voltage according to the estimated thickness of the dielectric 120.

The DC voltage control module 230 sets the DC voltage of the DC power supply unit 140 for the fixed electrode 130 in response to the estimated thickness of the dielectric 120 to maintain the chucking force of the fixed electrode 130. .

For example, when the capacitance C is known through the capacitance measurement module 210, the thickness estimating unit 220 obtains an estimated value of the thickness of the dielectric 120 corresponding to a change in the capacitance, previously DB.

Then, the DC voltage control module 230 is capable of calculating the DC voltage (V) to be applied to the chuck body 110 according to equation ⑧ of [FIG. 3] in order to maintain the original constant chucking force (F). .

At this time, according to the expression ⑧ in [Figure 3], the DC voltage control module 230 also knows the 'D' value to calculate the DC voltage (V) to be applied to the chuck body 110, which is a thickness estimation unit. 220, the 'D' value can be estimated from the DB.

On the other hand, 'F' in [Fig. 3] also shows the same meaning as the chucking force as an electrostatic force, and since the optimum value for chucking the original wafer is determined, the 'F' value is already known and the 'C' value is known. When the 'D' value can be estimated, as a result, the DC voltage control module 230 controls the DC power supply unit 140 according to the expression ⑧ of [FIG. 3] so that the DC power supply unit 140 is a chuck body. It is possible to determine the DC voltage (V) to be applied to (110).

On the other hand, the electrostatic chuck device having the chucking force maintaining device according to the third embodiment of the present invention, the capacitance measurement module 210, thickness measurement unit 220, DC voltage control of [Fig. It comprises a module 230.

And, the electrostatic chuck device having a chucking force maintaining device according to a third embodiment of the present invention, as shown in [Fig. 6], the chuck body 110, dielectric 120, fixed electrode 130, DC power supply It may be configured to further include a unit 140.

Since the chuck body 110, the dielectric 120, the fixed electrode 130, and the DC power supply unit 140 according to the third embodiment of the present invention are the same as the first embodiment of the present invention, detailed description thereof is omitted. do.

In addition, the electrostatic chuck device having the chucking force maintaining device according to the third embodiment of the present invention may be configured to further include a process chamber 150 and a shower head 160 as shown in FIG. 6.

Here, since the process chamber 150 and the shower head 160 according to the third embodiment of the present invention are the same as the first embodiment of the present invention, detailed descriptions thereof will be omitted.

10: wafer
20: electrostatic chuck assembly
30: DC power supply unit
40: process chamber
50: shower head
110: chuck body
111: support filler
112: rotor
120: dielectric
130: fixed electrode
140: DC power supply unit
150: process chamber
151: no access
160: shower head
210: capacitance measurement module
211: Test wafer
212: first electrode terminal
213: 3rd electrode terminal
213 ': 5th electrode terminal
214: second electrode terminal
215: fourth electrode terminal
215 ': 6th electrode terminal
216: capacitance measurement unit
217: Electric capacity measuring unit
217 ': Electric capacity measuring unit
220: thickness estimation unit
230: DC voltage control module

Claims (5)

A chuck body, a dielectric body integrally connected to the upper surface of the chuck body and for mounting the wafer on its upper surface by electrostatic force, and mounted inside the chuck body for chucking force of the chuck body against the wafer An apparatus for maintaining the chucking force of an electrostatic chuck, comprising a fixed electrode for charging the chuck body and a DC power supply unit for supplying DC power to the fixed electrode,
Capacitance measurement module 210 for measuring the electric capacity that changes according to the change in the thickness of the dielectric;
A thickness estimation unit 220 for estimating the thickness of the dielectric based on the capacitance measured by the capacitance measurement module;
A DC voltage control module 230 that sets a DC voltage of the DC power supply unit to the fixed electrode in response to the estimated thickness of the dielectric to maintain the chucking force of the fixed electrode;
An apparatus for maintaining a chucking force of an electrostatic chuck, which comprises a.
The method according to claim 1,
The capacitive measurement module 210,
A conductor probe connected to an upper surface of the dielectric, a first electrode terminal 212 in charge of any one of a (+) electrode and a (-) electrode;
A second electrode terminal 214 connected to a lower portion of the chuck body and in charge of an electrode opposite to the first electrode terminal among (+) and (-) electrodes;
An electric capacity measurement unit 216 which is energized to the first electrode terminal and the second electrode terminal to measure an electric capacity between the first electrode terminal and the second electrode terminal;
An apparatus for maintaining a chucking force of an electrostatic chuck, comprising:
The method according to claim 1,
The capacitive measurement module 210,
A test-only wafer 211 mounted on an upper surface of the dielectric;
A third electrode terminal 213 which is connected to an upper surface of the wafer for testing and is in charge of any one of (+) and (-) electrodes;
A fourth electrode terminal 215 connected to a lower portion of the chuck body and in charge of an electrode opposite to the third electrode terminal of the (+) electrode and the (-) electrode;
An electric capacity measuring unit 217 which is energized to the third electrode terminal and the fourth electrode terminal to measure the electric capacity between the third electrode terminal and the fourth electrode terminal;
An apparatus for maintaining a chucking force of an electrostatic chuck, comprising:
The method according to claim 1,
The capacitive measurement module 210,
A fifth electrode terminal 213 'connected to one of the (+) and (-) electrodes of the fixed electrode;
A sixth electrode terminal 215 'connected to one of the (+) electrode and the (-) electrode of the fixed electrode and the other electrode of the fifth electrode;
An electric capacity measuring unit 217 'that is energized to the fifth electrode terminal and the sixth electrode terminal to measure an electric capacity between the fifth electrode terminal and the sixth electrode terminal;
An apparatus for maintaining a chucking force of an electrostatic chuck, comprising:
Chuck body 110;
A dielectric 120 for integrally connected to the upper surface of the chuck body and seating the wafer on its upper surface by electrostatic force;
A fixed electrode 130 mounted on the inside of the chuck body to charge the chuck body for a chucking force of the chuck body with respect to the wafer;
A DC power supply unit 140 that supplies DC power to the fixed electrode;
Capacitance measurement module 210 for measuring the electric capacity that changes according to the change in the thickness of the dielectric;
A thickness estimation unit 220 for estimating the thickness of the dielectric based on the capacitance measured by the capacitance measurement module;
A DC voltage control module 230 that sets a DC voltage of the DC power supply unit to the fixed electrode in response to the estimated thickness of the dielectric to maintain the chucking force of the fixed electrode;
An electrostatic chuck device having a chucking force holding device comprising a.

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