KR20230119753A - Electrostatic Device And The Operating Method Of The Same - Google Patents

Abstract

An electrostatic device according to an embodiment of the present invention includes an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer and having a gap space; and a power source for applying a voltage to the electrostatic electrode layer. The dechucking method of the electrostatic device includes applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and dechucking by applying a second voltage having an opposite polarity to the first voltage to erase the first interfacial charge between the gap space and the dielectric layer.

Description

Electrostatic Device And The Operating Method Of The Same

The present invention relates to electrostatic devices, and more particularly to electrostatic devices and methods of operation thereof.

An electrostatic chuck is a device that adsorbs and fixes a substrate by using an electrostatic force generated by a difference in electric potential.

Electrostatic chucks are mainly used in substrate processing devices and transfer devices.

An object to be solved by the present invention is to provide an electrostatic device that maximizes electrostatic power by a difference in permittivity.

An object to be solved by the present invention is to provide an electrostatic device that maximizes electrostatic power by a difference in electrical conductivity.

An object to be solved by the present invention is to provide an electrostatic device that minimizes interfacial charge.

An electrostatic device according to an embodiment of the present invention includes an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer and having a gap space; and a power source for applying a voltage to the electrostatic electrode layer. The dechucking method of the electrostatic device includes applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and dechucking by applying a second voltage having an opposite polarity to the first voltage to erase the first interfacial charge between the gap space and the dielectric layer.

In one embodiment of the present invention, the first voltage is V0, the second voltage is V1, the relaxation time is τ, and the application time (t) of the second voltage is given as follows.

In one embodiment of the present invention, a relaxation time defined by resistance and capacitance of the dielectric layer and the gap space may be greater than an application time of the second voltage.

In an embodiment of the present invention, an absolute value of the second voltage may be greater than an absolute value of the first voltage.

In one embodiment of the present invention, the absolute value of the second voltage is equal to the absolute value of the first voltage, and the application time of the second voltage is defined by the resistance and capacitance of the gap space. It can be 0.69 times the time.

In one embodiment of the present invention, the absolute value of the second voltage is twice the absolute value of the first voltage, and the application time of the second voltage is defined by the resistance and capacitance of the gap space. It can be 0.40 times the time.

In one embodiment of the present invention, the absolute value of the second voltage is three times the absolute value of the first voltage, and the application time of the second voltage is defined by the resistance and capacitance of the gap space. It can be 0.287 times the time.

An electrostatic device according to an embodiment of the present invention includes an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer and having a gap space; and a power source for applying a voltage to the electrostatic electrode layer. The dechucking method of the electrostatic device includes applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and dechucking the power source to reduce the first interfacial charge by applying a second voltage greater than the first voltage to induce a discharge in the gap space.

In one embodiment of the present invention, the ratio of the electrical conductivity of the gap space to the electrical conductivity of the dielectric layer may be greater than the ratio of the dielectric constant of the gap space to the dielectric constant of the dielectric layer.

An electrostatic device according to an embodiment of the present invention, an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer; and and a power source for applying a voltage to the electrostatic electrode layer. The power source applies a first voltage to adsorb the substrate, and the power source applies a second voltage having a polarity opposite to that of the first voltage to dechuck the substrate.

In one embodiment of the present invention, the first voltage is V0, the second voltage is V1, the relaxation time is τ, and the application time (t) of the second voltage is given as follows.

The present invention can provide an electrostatic device that maximizes electrostatic power due to a difference in permittivity.

The present invention can provide an electrostatic device that maximizes electrostatic power by a difference in electrical conductivity.

The present invention provides an electrostatic device that minimizes interfacial charge.

1 is a conceptual diagram illustrating the basic structure of an electrostatic device according to an embodiment of the present invention.
2 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.
3A shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.
3B shows an electric field in a second region when a permittivity ratio of an electrostatic device according to an embodiment of the present invention is 0.1.
4 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.
5 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.
6 shows an interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.
7 shows an interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.
8 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.
9 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.
10 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.
11 shows the strength of the electric field in the second area over time.
12 shows the strength of the electric field in the second region over time.
13 shows the strength of the electric field in the second region over time.
14A shows the strength of the electric field in the second region over time.
14B shows the strength of the electric field in the second region over time.
15 shows the strength of the electric field in the second area over time.
16A shows the strength of the electric field in the second area over time.
16B shows the strength of the electric field in the second region over time.
17 is a conceptual diagram illustrating a parallel connection structure of second dielectric layers according to an embodiment of the present invention.
18 is a conceptual diagram illustrating a parallel connection structure of second dielectric layers according to an embodiment of the present invention.
19 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
20 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
21 shows the electric field of an electrostatic device according to an embodiment of the present invention.
22 shows the interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.
23 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
24 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
25A is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
25B is a conceptual diagram explaining the operation of the electrostatic device of FIG. 25A.
25C is a conceptual diagram illustrating the operation of the electrostatic device of FIG. 25A.
25D is a conceptual diagram explaining the operation of the electrostatic device of FIG. 25A.
26 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
26 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
27 is a conceptual diagram illustrating the structure of an electrostatic device according to an embodiment of the present invention.
28 is a conceptual diagram illustrating the structure of an electrostatic device according to an embodiment of the present invention.
29 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
30 is a conceptual diagram illustrating a typical electrostatic device.
31 to 33 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.
34 to 36 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.
37 to 44 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.
45 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.
46 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

The present invention provides an electrostatic device that increases electrostatic power, changes interfacial charge density, and adjusts relaxation time. The substrate or adsorbate may be a semiconductor substrate, a glass substrate, a plastic substrate, or a metal substrate. A conductive layer may be coated on one surface of the dielectric substrate. In the present invention, the air gap includes air at atmospheric pressure, gas at low pressure, and a state of extreme vacuum.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete, and the spirit of the present invention will be sufficiently conveyed to those skilled in the art. In the drawings, elements are exaggerated for clarity. Parts designated with like reference numerals throughout the specification indicate like elements.

An operating principle of a two-layer electrostatic device according to an embodiment of the present invention will be described.

1 is a conceptual diagram illustrating the basic structure of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 1 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 .

The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2.

The power source 130 may apply a voltage between the first electrode and the second electrode. The power source may be a DC power source, a DC pulse power source, an AC power source, or a DC biased AC power source.

The first electrode 110 is an electrostatic electrode for providing electrostatic power, and the second electrode 120 may be a substrate, a conductive adsorbed material, or a conductive layer coated on the adsorbed material. The first electrode 110 may be a conductor or a semiconductor. The second electrode 120 may be a conductive substrate or a semiconductor substrate. The conductive layer may be a conductor or a semiconductor.

If the first electrical conductivity (σ1) and the second electrical conductivity (σ2) are ignored, the electric fields (E1, E2) of the first region and the second region are given as follows.

[Equation 1]

Here, V ₀ is a potential difference applied between the first electrode 110 and the second electrode 120 .

The electrostatic pressure (f) of the second electrode by the second region is given as follows.

[Equation 2]

When the first electrical conductivity (σ1) and the second electrical conductivity (σ2) are considered, using Maxwell's equation and the continuity equation, the electric field E1 in the first region and the electric field E2 in the second region are in a steady state (steady state) state) is given as:

[Equation 3]

The surface charge density (ρ _si ) of the interface between the first region and the second region is given by

[Equation 4]

The electrostatic pressure (f) of the second electrode in the second region is given as: That is, the electrostatic pressure of the second electrode is given by

[Equation 5]

The electric field E1 of the first region and the electric field E2 of the second region are given as follows according to time t in the transient state.

[Equation 6]

That is, the electric field is given by the permittivity in the initial state, determined by the permittivity and the surface charge density in the transition state, and the electric field is given only by the electrical conductivity in the normal state.

The interfacial surface charge density (ρ _si ) is given in the transient state as:

[Equation 7]

Here, τ is the relaxation time or time constant (time constant).

[Temperature dependence of permittivity]

The permittivity of a dielectric may increase with temperature. As the permittivity changes with temperature, the electric field changes, and the electrostatic force may change with temperature.

[Temperature dependence of resistivity]

The resistivity of a dielectric may decrease with temperature. Electrostatic power can change with temperature.

[Change in resistivity according to composition]

For example, alumina is formed by adding TiO2, and the specific resistance may vary according to the addition rate of TiO2. The first dielectric layer 122 may be a high dielectric such as alumina, and the second dielectric layer 124 may be a low dielectric such as an air gap.

The first dielectric layer 122 may include at least one of aluminum oxide, aluminum nitride, magnesium oxide, iridium oxide, tantalum oxide, hafnium oxide (HfO 2 ), zirconium oxide (ZrO 2 ), barium oxide, and titanium oxide. there is,

The second dielectric layer 124 has a second permittivity. The second dielectric layer 124 may be a low dielectric constant material. The second dielectric layer is a vacuum layer, a gas layer, an air layer, silicon oxide, silicon nitride, silicon oxynitride, polyimide, poly(arylene ether) (PAE), cyclobutane derivative, polysilsesquioxane, fluorinated amorphous carbon, Xorogel, nanoporous organic silicate may contain at least one.

[Electric field in the second region according to the permittivity ratio when resistivity is ignored]

2 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 2, the total thickness (d) is 10 um, and the thickness (d2) of the second dielectric layer 124 is 1 um, 2 um, 5 um according to the dielectric constant ratio (ε2 / ε1) of the second region The second electric field E2 is displayed. When the permittivity ratio (ε2/ε1) is 0.5 or less, the second electric field E2 in the second region rapidly increases. As the thickness d2 of the second dielectric layer 124 decreases and the permittivity ratio ε2/ε1 decreases, the strength of the second electric field E2 increases. Accordingly, the electrostatic force increases. To maximize the dielectric constant ratio, the second dielectric layer 124 may be air or vacuum.

[Electric field in the second region according to the thickness of the second dielectric layer when resistivity is ignored]

3 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 3 , when the permittivity ratio (ε2/ε1) is 0.01, 0.1, 0.2, and 0.5, the strength of the second electric field E2 according to the thickness d2 of the second dielectric layer is displayed. When the thickness ratio (d2/d) of the second dielectric layer is 0.4 or less (4 um when the total thickness is 10 um), the strength of the electric field E2 in the second region rapidly increases. Preferably, the thickness ratio (d2/d) of the second dielectric layer may be 0.2 or less. For example, when the dielectric constant ratio (ε2/ε1) is 0.1, the strength of the electric field E2 in the second region may increase tenfold as the thickness d2 of the second dielectric layer decreases to zero. That is, as the thickness d2 of the second dielectric layer decreases, the strength of the electric field E2 in the second region increases.

The strength of the electric field E2 in the second region may be less than or equal to the dielectric breakdown field. For example, when the second dielectric layer 124 is air at atmospheric pressure, the breakdown electric field may be about 3 MV/m.

For example, when the second dielectric layer 124 is an extreme vacuum layer, the breakdown electric field may be about 20 MV/m.

For example, when the dielectric constant ratio (ε2/ε1) is 0.1 and the second dielectric layer 124 is a vacuum layer, in order to achieve an electrostatic pressure of about 10 Torr, an electric field in the second region is required to be 10 MV/m. do. When the total thickness d is 100 um and the thickness d2 of the second dielectric layer 124 is 10 um, a voltage of about 200 V is required.

For example, when the dielectric constant ratio (ε2/ε1) is 0.1 and the second dielectric layer is a vacuum layer, an electric field in the second region is required to be 20 MV/m to achieve a constant voltage of about 40 Torr. When the total thickness is 100 um and the thickness d2 of the second dielectric layer is 10 um, a voltage of about 285 V is required.

When the dielectric constant ratio (ε2/ε1) is 0.1, even when the thickness d2 of the second dielectric decreases, the second electric field E2 does not increase infinitely and converges to a constant value. Accordingly, when the dielectric constant ratio (ε2/ε1) is greater than or equal to 0.1 and the thickness ratio (d2/d) of the second dielectric layer is less than or equal to 0.05, the second electric field E2 is substantially constant.

When the first dielectric constant ε1 of the first dielectric layer 122 is greater than the second dielectric constant ε2 of the second dielectric layer, when the second dielectric layer 124 partially replaces the first dielectric layer 122, Electrostatic power may increase compared to the case where only the first dielectric layer is used. However, the thickness (d2) of the second dielectric layer may be less than or equal to a predetermined value with respect to the total thickness (d) given as follows.

[Equation 8]

For example, when the relative permittivity of the first dielectric layer is 10 and the relative permittivity of the second dielectric layer is 1, the thickness d2 of the second dielectric layer may be 0.25 d.

When electrical conductivity is neglected, it is difficult to achieve a permittivity ratio (ε2/ε1) of 0.01 or more in reality. Accordingly, in order to increase the strength of the second electric field E2, the thickness of the second dielectric layer may decrease.

The characteristics of the case in which resistivity is considered are explained.

[Electric field according to electrical conductivity ratio when resistivity is considered]

4 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 4 , the first dielectric layer 122 has a first dielectric constant ε1 and a first electrical conductivity σ1, and the second dielectric layer 124 has a second dielectric constant ε2 and a second electrical conductivity ( σ2). In a steady state, the electric field E2 of the second region does not depend on the permittivity but only on the electrical conductivity.

The total thickness (d) is 10 um, and the electric field (E2) of the second dielectric layer is displayed according to the electrical conductivity ratio (σ2/σ1) for the thickness (d2) of the second dielectric layer of 1 um, 2 um, and 5 um. When the permittivity ratio (ε2/ε1) is 0.1 and the electrical conductivity ratio (σ2/σ1) is 0.5 or less, the electric field in the second region increases rapidly. As the thickness of the second dielectric layer decreases and the electrical conductivity ratio (σ2/σ1) decreases, the strength of the second electric field E2 increases. Accordingly, the electrostatic force increases.

When an external voltage is applied between the first electrode and the second electrode, the initial second electric field is determined by the permittivity (permittivity ratio = 0.1) at point A. Then, by the electrical conductivity ratio (σ2/σ1 = 1,000) due to the first dielectric layer and the second dielectric layer, the second electric field E2 reaches a steady state and reaches a new electric field E2 at point A'. Therefore, in order to use a high second electric field, it is desirable that the relaxation time be sufficiently large.

In a normal state, in order to increase the second electric field E2, the electrical conductivity ratio (σ2/σ1) may be 0.5 or less. Preferably, the electrical conductivity ratio (σ2/σ1) may be 0.1 or less.

On the other hand, when the electrical conductivity ratio (σ2/σ1) is as small as 0.1 or less, the relaxation time is preferably sufficiently small in order to use a high second electric field.

[Electric field according to thickness when resistivity is considered]

5 shows an electric field in a second region of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 5, when the electrical conductivity ratio (σ2/σ1) is 0.01, 0.1, 0.2, and 0.5, the strength of the second electric field E2 according to the thickness d2 of the second dielectric layer 124 is displayed. . The permittivity ratio (ε2/ε1) is 0.1. When the thickness ratio (d2/d) of the second dielectric layer 124 is less than 0.4 (the total thickness (d) is 10 um, d2 = 4 um), the strength of the electric field E2 in the second region rapidly increases. Preferably, the thickness ratio (d2/d) of the second dielectric may be 0.2 (2um) or less.

For example, in the case of having an electrical conductivity ratio (σ2/σ1) of 0.1, the strength of the electric field E2 in the second region may increase 10 times as the thickness d2 of the second dielectric decreases to 0. . However, in the case of having an electrical conductivity ratio (σ2/σ1) of 0.1, the strength of the electric field does not change significantly when the thickness ratio (d2/d) of the second dielectric is 0.05 or less.

An electrical conductivity ratio (σ2/σ1) of 0.1 or less can be easily achieved. For example, when impurities are added to the first dielectric layer, the electrical conductivity of the first dielectric layer may change.

For example, when the electrical conductivity ratio (σ2/σ1) is 0.01, the strength of the electric field greatly changes when the thickness ratio (d2/d) of the second dielectric is 0.05 or less.

Point A is the strength of the electric field determined by the permittivity ratio (0.1) right after the external voltage is applied. Point A' is the strength of the electric field determined by the electrical conduction ratio in the steady state. The arrival from the initial state (A) to the steady state (A') is determined by the relaxation time. The relaxation time may be within a few seconds. Preferably, it may be desirable to be within several hundred milliseconds.

The second dielectric layer 124 is an air gap (or vacuum gap), and the thickness d2 of the air gap may be 0.01 to 0.2 with respect to the total thickness of the first dielectric layer and the air gap.

When a high electric field (or electrostatic force) is to be obtained using the electrical conductivity ratio (σ2/σ1), the electrical conductivity ratio (σ2/σ1) may be less than or equal to the permittivity ratio. Also, the thickness ratio (d2/d) of the second dielectric layer may be 0.1 or less.

An electrical conductivity ratio (σ2/σ1) may be 0.01 or less, and a thickness ratio (d2/d) of the second dielectric layer may be 0.1 or less. However, the intensity of the second electric field E2 is very sensitive to the thickness ratio (d2/d) of the second dielectric layer. The high second electric field can exceed the dielectric breakdown field. Accordingly, it may not be desirable for the thickness ratio (d2/d) of the second dielectric layer to be 0.01 or less.

[Interfacial surface charge density according to electrical conductivity ratio when resistivity is considered]

6 shows an interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 6 , the interfacial surface charge density (ρ _si ) depends on the electrical conductivity ratio (σ2/σ1) in a steady state. The total thickness (d) is 10 um, and the interface surface charge density (ρ _si ) according to the electrical conductivity ratio (σ2 / σ1) for the thickness (d2) of the second dielectric layer 124 is 1 um, 2 um, and 5 um displayed The permittivity ratio (ε2/ε1) is 0.1.

The unit of the surface charge density (ρ _si ) of the interface is represented by the product of the applied voltage (V) and the second permittivity of the second dielectric layer.

The first electrode is charged with a positive voltage and the second electrode is grounded. In this case, when the electrical conductivity ratio (σ2/σ1) is 0.1 or less, the interface surface charge density (ρ _si ) between the first dielectric layer and the second dielectric layer rapidly increases to a positive value. On the other hand, when the electrical conductivity ratio (σ2/σ1) is greater than or equal to 0.1, the interfacial surface charge density (ρ _si ) slowly increases to a negative value.

Typically, when the second electrode is grounded and a positive voltage is applied to the first electrode, the interfacial surface charge density (ρ _si ) is known to have a positive value. However, according to the present invention, the sign of the interfacial surface charge density (ρ _si ) depends on the permittivity ratio and the electrical conductivity ratio.

When the electrical conductivity ratio (σ2/σ1) is 0.1 and the permittivity ratio (ε2/ε1) is 0.1, the interface surface charge density (ρ _si ) is zero. This condition is a condition in which interfacial surface charge does not accumulate and can be used for fast dechucking. Also, since the interfacial surface charge density ρ _si is zero, the second electric field E2 does not change with time.

As the thickness d2 of the second dielectric layer 124 decreases and the electrical conductivity ratio σ2/σ1 decreases, the interfacial surface charge density ρ _si increases to a positive value. When the external voltage is removed, the interface surface charge density (ρ _si ) escapes to the outside with a characteristic time constant (or time constant or relaxation time).

According to an embodiment of the present invention, when the electrical conductivity ratio (σ2/σ1) is equal to the permittivity ratio (ε2/ε1), the interface surface charge density (ρ _si ) is zero. Thus, the interfacial surface charge does not need to be removed separately.

1 and 6 , the electrostatic device 10 includes an electrostatic electrode layer 110; a first dielectric layer (122) disposed on the electrostatic electrode layer; and a second dielectric layer 124 disposed on the second dielectric layer 122 . The first dielectric layer 122 has a first dielectric constant ε1 and a first electrical conductivity σ1, and the second dielectric layer 124 has a second dielectric constant ε2 and a second electrical conductivity σ2, The ratio (ε2/ε1) of the second permittivity to the first permittivity is equal to the ratio (σ2/σ1) of the second electric conductivity to the first electric conductivity.

The thickness d2 of the second dielectric layer 124 may be 0.01 to 0.2 with respect to the total thickness d of the first dielectric layer and the second dielectric layer. That is, the thickness ratio (d2/d) may be 0.01 to 0.2. A ratio of the second electrical conductivity to the first electrical conductivity may be 0.5 or less.

1 and 6 , the electrostatic device 10 includes an electrostatic electrode layer 110; a first dielectric layer (122) disposed on the electrostatic electrode layer; and an air gap 124 formed in the first dielectric layer. The air gap is filled with gas, the first dielectric layer 122 has a first dielectric constant ε1 and a first electrical conductivity σ1, and the gas has a second dielectric constant ε2 and a second electrical conductivity ( σ2), and the ratio of the second permittivity to the first permittivity (ε2/ε1) is equal to the ratio of the first electric conductivity to the second electric conductivity (σ2/σ1).

A thickness of the air gap may be 0.01 to 0.2 with respect to a total thickness of the first dielectric layer and the air gap. A ratio of the second electrical conductivity to the first electrical conductivity may be 0.5 or less.

1 and 6 , the electrostatic device 10 includes an electrostatic electrode layer 110; and a first dielectric layer 122 disposed on the electrostatic electrode layer; a substrate (120) disposed on the first dielectric layer; and a second dielectric layer 124 disposed between the lower surface of the substrate and the first dielectric layer. The first dielectric layer has a first dielectric constant ε1 and a first electrical conductivity σ1, the second dielectric layer has a second dielectric constant ε2 and a second electrical conductivity σ2, and The ratio of the second dielectric constant (ε2/ε1) is equal to the ratio of the second electrical conductivity to the first electrical conductivity (σ2/σ1).

The thickness (d2) of the second dielectric layer may be 0.01 to 0.2 with respect to the total thickness (d) of the first dielectric layer and the second dielectric layer. A ratio (σ2/σ1) of the second electrical conductivity to the first electrical conductivity may be 0.5 or less.

[Interfacial charge according to thickness when resistivity is considered]

7 shows an interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.

7, when the electrical conductivity ratio (σ2 / σ1) is 0.01, 0.1, 0.2, and 10, the interface surface charge density (ρ _si ) according to the thickness (d2) of the second dielectric layer 124 is displayed . The permittivity ratio (ε2/ε1) is 0.1.

When the electrical conductivity ratio (σ2 / σ1) is 0.01 (ie, smaller than the permittivity ratio (ε2 / ε1)), when the thickness ratio (d2 / d) of the second dielectric is 0.4 (4um) or less, the interface surface charge density ( ρ _si ) rapidly increases as the thickness d2 of the second dielectric decreases.

When the electrical conductivity ratio (σ2/σ1) is 0.1 (ie, equal to the permittivity ratio), the interfacial surface charge density (ρ _si ) is zero. When the interface surface charge density ρ _si is zero, there is no interface surface charge density remaining even when the external voltage is removed. Therefore, there is no charge to escape from the interface.

When the electrical conductivity ratio (σ2/σ1) is 0.2 (ie, greater than the permittivity ratio), the interfacial surface charge density (ρ _si ) has a negative value.

The thickness (d2) of the second dielectric layer may be 0.01 to 0.2 with respect to the total thickness (d) of the first dielectric layer and the second dielectric layer.

[Relaxation time according to resistivity ratio (ρ2/ρ1= σ1/σ2) when resistivity is considered]

8 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.

8, the total thickness (d) is 10 um, the thickness (d2) of the second dielectric layer 124 is 1 um, the relaxation time (or time constant) according to the resistivity ratio (ρ2 / ρ1 = σ1 / σ2) , τ) is indicated. The permittivity ratio (ε2/ε1) is 0.1. The relaxation time decreases as the permittivity ratio (ε2/ε1) decreases. In addition, the relaxation time decreases as the resistivity ratio (ρ2/ρ1) increases. The unit of the relaxation time is represented by the product of the second permittivity ε2 and the second resistivity ρ2.

The relaxation time decreases as the resistivity ratio increases. In the case of the Jonson-Rahbek type having a high resistivity ratio of 10 or more, the relaxation time decreases. On the other hand, in the case of the Coulomb type having a low specific resistance ratio of 10 or less, the relaxation time increases. In the case of the Jonson-Rabek type, it is desirable that the relaxation time be short in order to achieve a high electric field in the steady state. On the other hand, in the case of the Coolung type, since a low electric field is reached in a steady state, it is preferable that the relaxation time is sufficiently long.

[Relaxation time according to thickness when resistivity is considered]

9 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 9 , a relaxation time (or time constant) according to a resistivity ratio (ρ2/ρ1 = σ1/σ2) is displayed. The permittivity ratio (ε2/ε1) was fixed at 0.1. As the resistivity ratio (ρ2/ρ1) increases, the relaxation time decreases.

When the specific resistance ratio (ρ2/ρ1) is 10 (electric conductivity ratio is 0.1), the relaxation time (τ) is constant and does not depend on the thickness (d2) of the second dielectric.

When the specific resistance ratio (ρ2/ρ1) is less than 10, the relaxation time (τ) increases according to the thickness (d2) of the second dielectric.

When the specific resistance ratio (ρ2/ρ1) is greater than 10, the relaxation time (τ) decreases according to the thickness (d2) of the second dielectric.

When the ratio of electrical conductivity (σ2/σ1) decreases below 0.1 (Johnson-Rabek type), the relaxation time decreases and the interfacial charge density increases. Also, the intensity of the second electric field E2 increases. The relaxation time depends on the second resistivity and the second permittivity of the second dielectric layer. For example, in region X of FIG. 9 , when the relaxation time is considered, the thickness ratio (d2/d) of the second dielectric layer may be in the range of 0.01 to 0.1 in order to reduce the relaxation time.

When the electrical conductivity ratio (σ2/σ1) increases above 0.1 (Klong type), the relaxation time increases and the interfacial charge density increases to a negative value. Also, the intensity of the second electric field E2 decreases with time. Therefore, it is desirable that the relaxation time be long enough to maintain the high electric field in the initial state. The relaxation time depends on the second resistivity and the second permittivity of the second dielectric layer. For example, in area Y of FIG. 9 , when the relaxation time and the strength of the second electric field are considered, the thickness ratio (d2/d) of the second dielectric layer may be greater than or equal to 0.01. Preferably, the ratio (d2/d) of the thickness of the second dielectric layer may be 0.01 to 0.1. However, if the relaxation time is too long, interfacial charges may not be erased during detachment. Accordingly, for an appropriate level of relaxation time, an appropriate thickness ratio can be selected.

If a high resistivity material is deposited on the rear surface of a substrate to be adsorbed, the relaxation time increases rapidly due to the resistivity of the deposited material. Therefore, a system having a stable relaxation time is required even when a high resistivity material is deposited on the rear surface of the substrate.

For example, the ratio of the second conductivity to the first conductivity (σ2/σ1) may be smaller than the ratio (ε2/ε1) of the second permittivity to the first permittivity. Therefore, it is possible to accumulate positive interfacial charges. In this case, in order to reduce the relaxation time, the ratio (d2/d) of the thickness of the second dielectric layer may be 0.01 to 0.1.

Meanwhile, when the ratio of the second electrical conductivity to the first electrical conductivity is 0.01 or less, the relaxation time may decrease. In order to further reduce the relaxation time, the ratio of the thickness of the second dielectric layer (d2/d) may be 0.01 or more.

On the other hand, when the electrical conductivity ratio is 0.1 or more, the relaxation time increases. In order to increase the relaxation time, the thickness ratio (d2/d) of the second dielectric layer may be 0.01 to 0.2. The thickness of the second dielectric layer may be 0.01 to 0.2 level with respect to the total thickness of the first dielectric layer and the second dielectric layer.

The second electrical conductivity is the reciprocal of the second specific resistance, and the second specific resistance may be 10^12 Ωm or less. In the case of an air gap, the second resistivity may be 10^10 Ωm to 10^12 Ωm depending on the pressure and gas.

When the ratio of the second dielectric constant to the first dielectric constant is 0.1, and the ratio of the second electrical conductivity to the first electrical conductivity is 0.1 or less, positive interfacial charges are accumulated.

In conclusion, the relaxation time can be set according to the purpose. For example, in the case of a Coulomb type having an air gap as the second dielectric layer (eg, an electrical conductivity ratio (σ2/σ1) of 10 or more), the adsorption time may be set to several tens of seconds or more. In this case, when the ratio (d2/d) of the thickness of the second dielectric layer decreases to 0.01 or less, the relaxation time decreases, and thus the adsorption force decreases during the adsorption time, and unintentional desorption may occur. In order to prevent this, the ratio (d2/d) of the thickness of the second dielectric layer may be set to have a large value so as to have a relaxation time greater than the adsorption time.

For example, in the case of a Jonson-Rabek type having an air gap as the second dielectric layer (eg, the ratio of electrical conductivity (σ2 / σ1) is 0.1 or less), when the adsorption time is tens of seconds or more, the thickness of the second dielectric layer When the ratio (d2/d) of is decreased to 0.01 or less, the relaxation time increases and the intensity of the second electric field does not sufficiently increase during the adsorption time, so initial adsorption may be difficult. In order to prevent this, the ratio (d2/d) of the thickness of the second dielectric layer may be set to have a relatively large value so as to have a relaxation time smaller than the adsorption time.

[Relaxation time according to permittivity ratio when resistivity is considered]

10 shows a relaxation time (τ) of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 10, for the same resistivity ratio (ρ2/ρ1), when the permittivity ratio (ε2/ε1) increases, the relaxation time (τ) slightly decreases. That is, the relaxation time mainly depends on the resistivity ratio (ρ2/ρ1) rather than the permittivity ratio.

[Johnson-Rabeck type time-dependent electric field]

Case I d1=9 [um] d2=1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] σ1=100 [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm]

11 shows the strength of the electric field in the second area over time.

Referring to FIG. 11 , under the condition of Case I, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time. Case I may be of the Johnson-Rabeck type. In this case, the second electric field E2 increases with time from the initial value (0.7). The initial value (0.7) of the second electric field E2 may be determined by the characteristics of the dielectric. When the permittivity ratio (ε2/ε1) is 0.1, the electrical conductivity ratio (σ2/σ1) is 0.01, the thickness (d1) of the first dielectric layer is 9um, and the thickness (d2) of the second dielectric layer is 1um, the second electric field (E2) may increase with time with a relaxation time (τ).

For example, when the dielectric constant ratio (ε2/ε1) is 0.1 and the electrical conductivity ratio (σ2/σ1) is 0.01 (resistance ratio = 100), the relaxation time (τ) may be about 0.1 [ε2ρ2]. For example, when the second dielectric layer is a weak vacuum layer, ε2 is ε0 (vacuum permittivity), and ρ2 may be about 10^12 Ωm. In this case, the relaxation time τ may be about 1 second. The second electric field E2 may increase from 0.7 MV/m to 1.2 MV/m. In this case, the interface surface charge density (ρ _si ) has a positive value and accumulates at the interface.

Then, when the external voltage is removed, the interfacial surface charge density (ρ _si ) polarized charge (ΔP) by the dielectric is removed, and the positive interface surface charge density (ρ _si ) decays with time.

[Electric field according to Coulomb type time]

Case II d1=9 [um] d2=1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] σ1=0.5
σ1=10^(-4) [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm]

12 shows the strength of the electric field in the second region over time.

Referring to FIG. 12 , under the condition of Case II, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time. Case II may be of the Coulomb type. In this case, the second electric field E2 decreases with time from an initial value. The initial value of the second electric field E2 may be determined by the characteristics of the dielectric. When the dielectric constant ratio is 0.1, the electrical conductivity ratio is 0.5, the thickness of the first dielectric (d1) = 9um, and the thickness (d2) of the second dielectric are 1um, the second electric field (E2) has a relaxation time (τ) and a time may decrease depending on

For example, when the permittivity ratio (ε2/ε1) is 0.1 and the electrical conductivity ratio (σ2/σ1) is 0.5 (resistance ratio = 2), the relaxation time (τ) may be about 1 [ε2ρ2]. For example, when the second dielectric is a weak vacuum layer, ε2 is ε0 and ρ2 may be about 10^12 Ωm. In this case, the relaxation time may be about 10 seconds. The second electric field E2 may decrease from 0.7 MV/m to 0.25 MV/m in a steady state. In this case, the interface surface charge density (ρ _si ) has a negative value and accumulates at the interface.

Then, when the external voltage is removed, the interfacial surface charge density (ρ _si ) polarized charge (ΔP) by the dielectric is removed, and the negative interface surface charge density (ρ _si ) decays with time. Also, the absolute value of the second electric field E2 may decrease over time with a relaxation time τ.

[Interfacial surface charge density (ρ _si ) = 0 type electric field over time]

Case III d1=9 [um] d2=1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] σ1= 10 [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm]

13 shows the strength of the electric field in the second region over time.

Referring to FIG. 13 , under the condition of Case III, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time. Case III is the case where the interfacial surface charge density (ρ _si ) is zero. In this case, the second electric field E2 is constant with time in its initial value. The initial value of the second electric field E2 may be determined by the characteristics of the dielectric. When the permittivity ratio is 0.1, the electrical conductivity ratio is 0.1, the thickness of the first dielectric (d1) = 9um, and the thickness (d2) of the second dielectric are 1um, the second electric field (E2) has a relaxation time (τ), but the time can be constant according to

For example, when the dielectric constant ratio is 0.1 and the electrical conductivity ratio is 0.1 (resistance ratio = 10), the relaxation time (τ) may be about 1 [ε2ρ2]. For example, when the second dielectric is a weak vacuum layer, ε2 is ε0 and ρ2 may be about 10^12 Ωm. In this case, the relaxation time may be about 10 seconds. The second electric field E2 may be maintained at the same value over time at 0.7 MV/m. In this case, the interface surface charge density (ρ _si ) is zero, and no charge is accumulated at the interface.

Subsequently, when the external voltage is removed, the interface surface charge density (ρ _si ) polarized charge (ΔP) by the dielectric is removed, and the interface surface charge density (ρ _si ) is zero. Also, the second electric field E2 is zero.

[Comparison of characteristics]

steady state Case I Case II Case III E2 1.2 [MV/m] 0.25 [MV/m] 0.7 [MV/m] ρ _si positive value negative value 0 τ ~0.1 [ε2ρ2 sec] ~1 [ ε2ρ2 sec] ~1 [ ε2ρ2 sec]

[Bipolar voltage or electric field with increasing voltage]

14A shows the strength of the electric field in the second region over time.

Referring to FIG. 14A, under the condition of Case I, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time.

When an external voltage is applied, the interface surface charge density ρ _si has a positive value, and the electric field E2 of the second region increases with time.

Subsequently, when the electric field E2 of the second region is saturated, the polarity of the external voltage is changed. In this case, the second electric field E2 may have a negative value, and the absolute value of the second electric field E2 increases with time. When the polarity of the externally applied voltage is changed, the absolute value of the second electric field E2 has a relatively small value and has a low electrostatic power.

14B shows the strength of the electric field in the second region over time.

Referring to FIG. 14B, under the condition of Case I, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time.

When an external voltage is applied, the interface surface charge density ρ _si has a positive value, and the electric field E2 of the second region increases with time.

Subsequently, when the electric field E2 of the second region is saturated, the external voltage is further increased. In this case, the second electric field E2 instantaneously further increases, and the second electric field E2 may be greater than a breakdown (BD) electric field. Accordingly, when the second dielectric is an air gap, discharge occurs, interfacial charges are reduced by the discharge charges, and the second electric field E2 is reduced. However, the discharge may lead to an arc discharge.

Case IV d1=9.5 [um] d2=0.5 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] σ1=100 [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm]

15 shows the strength of the electric field in the second area over time.

Referring to FIG. 15 , under the condition of case IV, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time.

When an external voltage is applied, the interface surface charge density ρ _si has a positive value, and the electric field E2 of the second region increases with time.

Subsequently, when the electric field E2 of the second region is saturated, the polarity of the external voltage is changed. In this case, the second electric field E2 may have a positive value, the second electric field E2 decreases, passes the zero point, and the absolute value of the second electric field E2 increases with time. At the time when the polarity of the external voltage is changed, the absolute value of the second electric field E2 has a relatively small value, and the second electric field E2 has a zero value according to time.

16A shows the strength of the electric field in the second area over time.

Referring to FIG. 16A, under the condition of case II, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time.

When an external voltage is applied, the interface surface charge density ρ _si has a negative value, and the electric field E2 of the second region decreases with time.

Subsequently, when the electric field E2 of the second region is saturated, the polarity of the external voltage is changed. In this case, the second electric field E2 may have a negative value, and the absolute value of the second electric field E2 decreases with time. When the polarity of the external voltage is changed, the absolute value of the second electric field E2 has a relatively large value, and the absolute value of the second electric field E2 decreases with time.

16B shows the strength of the electric field in the second region over time.

Referring to FIG. 16B, under the condition of case II, the electric field E2 of the second dielectric layer 124 according to time is displayed according to time.

When an external voltage is applied, the interface surface charge density ρ _si has a negative value, and the electric field E2 of the second region decreases with time.

Subsequently, when the electric field E2 of the second region is saturated, the external voltage is further increased. In this case, the second electric field E2 may exceed the discharge electric field BD. Accordingly, when the second dielectric is an air gap, discharge occurs, interfacial charges increase due to the discharge charges, and the second electric field E2 decreases. However, the discharge may lead to an arc discharge. The absolute value of the interfacial charge further increases. However, the absolute value of the second electric field E2 may decrease.

[Parallel connection structure of second dielectric layer when electrical conductivity is ignored]

17 is a conceptual diagram illustrating a parallel connection structure of second dielectric layers according to an embodiment of the present invention.

Referring to FIG. 17 , in the electrostatic device 10a, a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1.

The second region is formed of a plurality of second dielectrics 124 and 124' having the same thickness d2. The second region may be divided into a plurality of sections according to permittivity (or electrical conductivity). For example, the third section has the same material properties as the first dielectric, the first section is the second main dielectric layer 124, has a second main permittivity ε2 and a second electrical main conductivity σ2, and has a thickness is d2. The second section is the second preliminary dielectric 124', has a second preliminary permittivity ε'2 and a second preliminary electrical conductivity σ'2, and has a thickness d2.

If the electrical conductivity is neglected, different electric fields can be obtained for each section. For example, the third section may have the lowest electric field as point C. In the first section, when the second main dielectric is an air gap, a high electric field may be obtained at point A. In the second period, the second preliminary dielectric is a silicon oxide film and may have a value smaller than the first permittivity (permittivity of alumina). In this case, the electric field in the second section may be slightly lower than the intensity of the electric field in the second main dielectric.

As a result, by connecting the second dielectric layer in parallel, desired physical properties can be secured. That is, if the third section is removed and only the first section and the second section are used, the strength of the electric field can be relatively increased.

[Parallel connection structure of the second dielectric layer when electrical conductivity is considered]

18 is a conceptual diagram illustrating a parallel connection structure of second dielectric layers according to an embodiment of the present invention.

Referring to FIG. 18 , in the electrostatic device 10b, a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1.

The second region is formed of a plurality of second dielectrics 124 and 124' having the same thickness. The second region may be divided into a plurality of sections according to electrical conductivity (or permittivity). For example, the third section has the same material properties as the first dielectric, the first section is the second main dielectric layer 124, has a second main permittivity ε2 and a second electrical main conductivity σ2, and has a thickness is d2. The second section is the second preliminary dielectric 124', has a second preliminary permittivity ε'2 and a second preliminary electrical conductivity σ'2, and has a thickness d2.

When electrical conductivity is considered, different electric fields can be obtained for each section. For example, the third section may have the lowest electric field as point C. In the first section, when the second main dielectric 124 is an air gap, a high electric field may be obtained at point A. In the second section, the second preliminary dielectric 124' is a silicon oxide film and may have a value smaller than the first electrical conductivity (electrical conductivity of alumina) of the first dielectric. In this case, the electric field E2' of the second section may be higher than the intensity of the electric field E2 in the second main dielectric at point B.

As a result, by connecting the second dielectric layer in parallel, desired physical properties can be secured. That is, the intensity of the electric field for each section may be relatively increased or decreased.

For example, a large current may flow in the third section due to low resistance. Accordingly, the third section may be removed, and only the second section and the third section may be used. Accordingly, it is possible to implement desired physical properties (an increase in the strength of an electric field while reducing a total current).

This concept can be performed in a mixture of series and parallel in a multilayer structure of two or more layers.

19 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 19 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1.

A conductive layer 129 may be disposed between the first dielectric layer 122 and the second dielectric layer 124 . The conductive layer 129 may be very thin compared to the first dielectric layer 122 or the second dielectric layer 122 . Even when the conductive layer 129 is present, the electric field and interfacial surface charge density behave the same.

The conductive layer 129 accumulates interfacial surface charge. Accumulated interfacial charge can be removed by being connected to ground through a switch. The conductive layer 129 may be a semiconductor or a conductor.

A conductive layer 129 is disposed between the first dielectric layer and the second dielectric layer. The conductive layer may be a semiconductor or a conductor. The conductive layer may accumulate interfacial charges. A thickness of the conductive layer may be thinner than that of the second dielectric layer.

Interfacial charges accumulated in the conductive layer may be connected to an external ground through a switch to be erased.

Alternatively, the first dielectric layer and the second dielectric layer may receive light from the light source 150 to generate electrons and holes, and the electrons or holes may move to the conductive layer 129 to control interfacial charge.

Referring to FIG. 19 , an electrostatic device 10c according to an embodiment of the present invention includes an electrostatic electrode layer 110; a first dielectric layer (122) disposed on the electrostatic electrode layer; a conductive layer (129) disposed on the first dielectric layer; and an air layer 124 disposed on the conductive layer. A protrusion (not shown) formed on the first dielectric layer forms an air layer between the adsorbed material 120 and the first dielectric layer 122 . The conductive layer is not buried in the first dielectric layer.

Referring to FIG. 27 , when the conductive layer is buried in the first dielectric layer or covered with another dielectric layer, another interfacial charge is generated. Thus, the conductive layer may be exposed to the air gap.

The conductive layer 129 may be selectively connected to ground through a switch. The conductive layer 129 may be electrically connected to a conductive material coated on the inside of a passage (not shown) for providing cooling gas to the air layer. The conductive layer may be a semiconductor or a metal. The conductive layer is a photoresistive layer having conductivity by receiving light and may be CdS.

Referring to FIG. 19 , an electrostatic device 10c according to an embodiment of the present invention includes an electrostatic electrode layer 110; a dielectric layer (122) disposed on the electrostatic electrode layer; protrusions (not shown) and depressions 124 formed in the dielectric layer; and a conductive layer 129 formed on a lower surface of the recessed portion. Adsorbing a substrate (or electrostatic electrode layer) on the dielectric layer by applying a first voltage by the power source 130; and removing the interfacial charge accumulated in the conductive layer 129 by grounding the conductive layer 129 after removing the first voltage to detach the substrate (or the electrostatic electrode layer). The method may further include removing interfacial charges by applying a second voltage having a polarity opposite to that of the first voltage.

[Electric field according to temperature control (heating means)]

20 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

21 shows the electric field of an electrostatic device according to an embodiment of the present invention.

22 shows the interfacial surface charge density of an electrostatic device according to an embodiment of the present invention.

Referring to FIGS. 20 to 22 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2.

The temperature control unit 140 may be disposed above, below, or around the first dielectric layer 122 to control the temperature of the first dielectric layer 122 and/or the second dielectric layer 124 . For example, when the second dielectric layer 124 is an air or vacuum layer, electrical conductivity of the second dielectric layer 124 may be substantially constant depending on temperature. Meanwhile, when the first dielectric layer 122 is a high dielectric material such as alumina, electrical conductivity of the first dielectric layer 122 may depend on temperature. The temperature control unit 140 may include at least one of a resistive heater, warm air, and an infrared generator.

At the first temperature T1, the electrical conductivity ratio (σ2/σ2) may be 0.01, and the permittivity ratio (ε2/ε1) may be 0.1. At the second temperature T2 lower than the first temperature, the dielectric constant ratio (ε2/ε1) may be 0.1, and the electrical conductivity ratio (σ2/σ2) may be 0.1.

For example, since the electrical conductivity ratio (σ2/σ2) is 0.01 at the first temperature T1, when the thickness d1 of the first dielectric is 9um and the thickness d2 of the second dielectric is 1um, The intensity of the electric field E2 of the second region may be about 2 MV/m, and the interface surface charge density may be 0.5 [Vε2]. Meanwhile, at the second temperature T2, the intensity of the electric field E2 in the second region may be about 0.8 MV/m, and the interface surface charge density ρ _si may be 0 [Vε2]. Accordingly, when the temperature of the first dielectric layer 122 is modulated with time, a strong second electric field is obtained at a high temperature, and the interfacial surface charge density ρ _si can be set to zero at a desired time and low temperature.

Alternatively, the temperature control unit 140 may change the operating characteristics by changing the temperature of the first dielectric layer 122 and/or the second dielectric layer 124 .

20 to 22 , an electrostatic device 10d according to an embodiment of the present invention includes an electrostatic electrode layer 110; a first dielectric layer (122) disposed on the electrostatic electrode layer; and a temperature controller 140 for controlling the temperature of the first dielectric layer. An air gap 124 formed in the first dielectric layer, the air gap is filled with gas, and the first dielectric layer 122 has a first permittivity ε1 and a first electrical conductivity σ1, The gas has a second permittivity ε2 and a second electrical conductivity σ2.

The temperature controller 140 heats the first dielectric layer 122 in a state in which an external voltage is applied to the electrostatic electrode layer, and the temperature controller 140 applies an external voltage to the electrostatic electrode layer. In this state, the first dielectric layer 122 is cooled. The first dielectric layer 122 has different electrical conductivity according to temperature.

The ratio (ε2/ε1) of the second permittivity to the first permittivity is equal to the ratio (σ2/σ1) of the second electric conductivity to the first electric conductivity.

In the cooled state, the first dielectric layer has a first dielectric constant and a first electrical conductivity, the second dielectric layer has a second dielectric constant and a second electrical conductivity, and the ratio of the second dielectric constant to the first dielectric constant is the first dielectric constant. It is equal to the ratio of the second electrical conductivity to the first electrical conductivity. Accordingly, in the cooled state, interfacial charge is removed. That is, while processing the substrate, the first dielectric layer is maintained at a high temperature to increase electrical conductivity and maintain high electrostatic power. The processing of the substrate may be substrate transfer, plasma etching, deposition process, and the like. On the other hand, when the processing of the substrate is completed, the first dielectric layer is set to a low temperature to reduce the electrical conductivity and thus the interfacial charge. Accordingly, when the external power is removed, it is possible to attach and detach immediately.

The present invention can also be applied to dielectrics other than air gaps.

[Interfacial surface charge density according to counter voltage pulse]

23 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 23 , in Case II, a first voltage is applied to operate the electrostatic device. The electric field E2 of the second region is changed to become saturated with time. If the electric field E2 of the second region is saturated, the interface may be charged with a negative interface surface charge density. A negative interfacial surface charge density may have a relatively large relaxation time (τ).

When removing the negative interfacial surface charge density, a second voltage having a polarity opposite to that of the first voltage may be applied. When a second voltage having a polarity opposite to that of the first voltage is applied, the time at which the interfacial charge becomes zero is given as follows.

[Equation 9]

When the magnitude of the second voltage is the same as that of the first voltage, the time t1 at which the interface surface charge density becomes zero may be 0.69 τ.

When the magnitude of the second voltage is twice the magnitude of the first voltage, the time t1 at which the interface surface charge density becomes zero may be 0.40 τ. When the magnitude of the second voltage is three times that of the first voltage, the time t1 at which the interface surface charge density becomes zero may be 0.287 τ.

However, the application time of the opposite voltage to remove the interfacial surface charge density can be relatively long due to the large relaxation time (τ).

The above description applies equally to Case I and the Johnson-Rabeck type.

1 and 23 , the electrostatic device 10 includes an electrostatic electrode layer 110; and a dielectric layer (122) disposed on the electrostatic electrode layer and having a gap space (124); and a power source 130 for applying a voltage to the electrostatic electrode layer. The dechucking method of the electrostatic device includes applying a first voltage (V0) to the power source 130 to adsorb the substrate 120 and accumulating a first interfacial charge between the dielectric layer and the gap space; and dechucking by applying, by the power supply 130, second voltages (V1 to V3) having opposite polarity to the first voltage to erase the first interfacial charge between the gap space and the dielectric layer.

A relaxation time defined by resistance and capacitance of the dielectric layer and the gap space is greater than application times t1 , t2 , and t3 of the second voltages V1 to V3 .

An absolute value of the second voltage may be greater than an absolute value of the first voltage.

For example, the absolute value of the second voltage is equal to the absolute value of the first voltage, and the application time of the second voltage is 0.69 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. there is.

For example, the absolute value of the second voltage is twice the absolute value of the first voltage, and the application time of the second voltage is 0.40 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. there is.

For example, the absolute value of the second voltage is three times the absolute value of the first voltage, and the application time of the second voltage is 0.287 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. there is.

1 and 14B, the electrostatic device 10 includes an electrostatic electrode layer 110; and a dielectric layer (122) disposed on the electrostatic electrode layer and having a gap space (124); and a power source 130 for applying a voltage to the electrostatic electrode layer. The dechucking method of the electrostatic device includes applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and dechucking the power source to reduce the first interfacial charge by applying a second voltage greater than the first voltage to induce a discharge in the gap space.

The ratio of the electrical conductivity of the gap space to the electrical conductivity of the dielectric layer (σ2/σ1) may be greater than the ratio of the dielectric constant of the gap space to the dielectric constant of the dielectric layer (ε2/ε1).

[Interfacial charge according to bipolar voltage]

24 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 24 , in Case II, a first voltage is applied to operate the electrostatic device. The electric field E2 of the second region is changed to become saturated with time. A negative interfacial surface charge density may have a relatively large relaxation time (τ).

After dividing the relaxation time τ into a plurality of sections, the positive first voltage and the negative second voltage may be alternately applied. Accordingly, the interfacial surface charge density does not accumulate over time and can maintain an almost zero value. Preferably, the relaxation time τ may be divided into 10 or more sections.

Accordingly, when the external voltage is removed at the time to remove the electrostatic force, the interface surface charge density becomes almost zero, and the electrostatic force can be immediately removed.

Even in cases I, III, and IV, after dividing the relaxation time τ into a plurality of sections, the positive first voltage and the negative second voltage may be alternately applied. Accordingly, the interfacial surface charge density does not accumulate over time and can maintain an almost zero value.

1 and 24 , an electrostatic device 10 according to an embodiment of the present invention includes an electrostatic electrode layer 110; and first and second dielectric layers 122 and 124 disposed on the electrostatic electrode layer; and a power source 130 for applying a voltage to the electrostatic electrode layer.

The method of operating the electrostatic device may include applying a first voltage to the power source 130 to adsorb the substrate 120 on the dielectric layer and to accumulate first interfacial charges; and applying a second voltage of opposite polarity to the first voltage to erase the first interfacial charge accumulated between the first dielectric layer and the second dielectric layer with the charge of opposite polarity.

The first voltage and the second voltage may be alternately repeated, and an application time of the first voltage may be smaller than a time constant of the first interfacial charge.

An application time of the first voltage may be the same as an application time of the second voltage, and a time constant of the first interfacial charge may be 10 seconds or more. For example, it may be effective in the Coulombic type.

The first voltage may have a positive value, the substrate 120 may be negatively charged at the first voltage, and the first interfacial charge may have a negative value.

1 and 24 , an electrostatic device 10 according to an embodiment of the present invention includes an electrostatic electrode layer 110; and first and second dielectric layers 122 and 124 disposed on the electrostatic electrode layer; and a power source 130 for applying a voltage to the electrostatic electrode layer. The method of operating the electrostatic device includes applying a first voltage to the power source 130 to adsorb the substrate 120 and accumulating a first interfacial charge between the first dielectric layer 122 and the second dielectric layer 124. step; and applying a second voltage having an opposite polarity to the first voltage to accumulate the first interfacial charge and interfacial charge having an opposite polarity to adsorb the substrate 120 .

An application time of the first voltage is smaller than a time constant of the first interfacial charge. An application time of the first voltage may be the same as an application time of the second voltage, and a time constant of the first interfacial charge may be 10 seconds or more. The first voltage and the second voltage may be alternately repeated.

[Interfacial charge according to UV/visible light irradiation]

25A is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

25B is a conceptual diagram explaining the operation of the electrostatic device of FIG. 25A.

25C is a conceptual diagram illustrating the operation of the electrostatic device of FIG. 25A.

25D is a conceptual diagram explaining the operation of the electrostatic device of FIG. 25A.

26 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIGS. 25A to 25D and 26 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2. The electrostatic device may include a light providing unit 150 that controls an interfacial surface charge density.

The light providing unit 150 may provide ultraviolet/visible light to an interface between the first dielectric layer and the second dielectric layer. Ultraviolet/visible light can generate electron-holes in either the first dielectric layer or the second dielectric layer to control the interfacial surface charge density. A wavelength of the light irradiation means may be greater than or similar to the bandgap energy of the dielectric. Alternatively, the wavelength of the light irradiation unit may be in the ultraviolet region.

The light providing unit 150 may include an optical fiber 151 and an ultraviolet light source 152 . The optical fiber may be a quartz material capable of transmitting ultraviolet rays. The optical fiber 150 may pass through the first electrode and the dielectric layer and be exposed to the second dielectric layer. Preferably the second dielectric layer may be an air gap. A surface of the dielectric layer providing a lower surface of the gap space may be roughened for diffusion.

Referring to FIG. 25B, a first voltage is applied between the first electrode and the second electrode. In this case (Johnson-Rabek type), the second dielectric layer may be an air gap. The interfacial charge has a positive value and changes to a saturation state with a relaxation time. Light pulses may be irradiated to the first dielectric layer 122 and the second dielectric layer 124 prior to saturation (or steady state). In this case, the second dielectric layer 124 may be an air gap. Light pulses can quickly reach saturation by creating electron-hole pairs to reduce the relaxation time.

When a positive voltage is applied to the first electrode 110 and the second electrode is grounded, the first electrode may be positively charged and the second electrode may be negatively charged. The interfacial charge may have a positive value. When external light is irradiated, electron-hole pairs generated in the first dielectric layer may be formed. Electrons may move in the direction of the first electrode, and holes may move in the direction of the interface. Accordingly, the interfacial charge density can reach saturation in a short time. It is assumed that the physical properties of the air gap are not changed by light irradiation.

Subsequently, the first voltage is removed between the first electrode and the second electrode. In this case, the interfacial charge can be erased with a relaxation time. The first electrode may be grounded, and the second electrode may be grounded. Accordingly, since the interfacial charge has a positive value, the first electrode may be negatively charged and the second electrode may be negatively charged. The first electric field E1' of the first region may be in the direction of the first electrode, and the second electric field E2' of the second region may be in the direction of the second electrode. When a light pulse is irradiated, the first dielectric layer may generate electron-hole pairs. Electrons may move toward the interface, and holes may move toward the first electrode. Accordingly, interface charges can be erased at a faster rate.

On the other hand, when the electrical conductivity of each dielectric is changed by light irradiation, a new equilibrium state (steady state) can be reached.

Referring to FIG. 25C , a first voltage is applied between the first electrode and the second electrode. In this case (Johnson-Rabek type), the second dielectric layer may be an air gap. The interfacial charge has a positive value and changes to a saturation state with a relaxation time. Light pulses may be irradiated onto the dielectric prior to saturation. In this case, the light pulse may reduce the relaxation time by generating charge-holes.

Subsequently, a second voltage having an opposite polarity to the first voltage is applied between the first electrode and the second electrode. The first electrode may be negatively charged and the second electrode may be positively charged. The interfacial charge has a positive value. Light may be irradiated to generate electron-hole pairs in the first dielectric layer. Electrons may move toward the interface, and holes may move toward the first electrode. In this case, the interfacial charge may be charged with a charge of opposite polarity with a relaxation time. When the light pulse is irradiated, the interfacial charge can be charged with a charge of opposite polarity at a faster rate. That is, when a second voltage of opposite polarity is applied and light is irradiated for dechucking, the interfacial charge reaches a zero state more quickly. When the light and/or the second voltage is removed while the interfacial charge is zero, the interfacial charge is removed.

Referring to FIG. 25D , a first voltage is applied between the first electrode and the second electrode. In this case (Coulomb type), the second dielectric layer may be an air gap. The interfacial charge has a negative value and changes to a saturation state with a relaxation time. A light pulse may be irradiated to the first dielectric prior to saturation. In this case, the light pulse may generate charge-holes to erase interfacial charges.

Subsequently, the first voltage may be removed between the first electrode and the second electrode. In this case, the interfacial charge may disappear with a relaxation time. When a light pulse is irradiated, the interfacial charge can be erased at a faster rate. That is, when light is irradiated for dechucking, the interfacial charge may more quickly reach a zero state.

Referring to FIG. 26 , the electrostatic devices 10e and 10f include an electrostatic electrode layer 110; dielectric layers 122 and 124 disposed on the electrostatic electrode layer; and a light providing unit 150 providing visible/ultraviolet rays to the dielectric layer. The light providing unit 150 may include an optical fiber 151 and a light source 152 .

The at least one optical fiber 151 includes at least one optical fiber disposed in the air gap 124 passing through the electrostatic electrode layer 110 and the dielectric layer 122 . The optical fiber can transmit ultraviolet light. The core and cladding of the optical fiber 151 may be made of quartz. A surface of the dielectric layer providing a lower surface of the air gap 124 may be roughened for diffusion. The light providing unit 150 may generate electron-holes in the dielectric layer to erase interfacial charges.

25 and 26, the electrostatic devices 10e and 10f include an electrostatic electrode layer 110; dielectric layers 122 and 124 disposed on the electrostatic electrode layer; and a light providing unit 150 providing ultraviolet rays to the dielectric layers 122 and 124 . The dechucking method of the electrostatic device may include applying a first voltage to the electrostatic electrode layer 110; removing the first voltage applied to the electrostatic electrode layer 110; providing light to the dielectric layers 122 and 124 through the light providing unit 150; and erasing electric charges accumulated on the dielectric layers 122 and 124 or the rear surface of the substrate 120 disposed on the dielectric layer by the light.

Removing the first voltage applied to the electrostatic electrode layer and providing the light may be simultaneously performed. The light may be provided after removing the first voltage applied to the electrostatic electrode layer. After removing the first voltage applied to the electrostatic electrode layer, counter pulses of opposite polarities and the light may be provided sequentially or simultaneously.

[Electric field in plasma situation]

In a situation where plasma is generated, the electrostatic device may operate. Specifically, the second electrode is a semiconductor substrate to be processed, and plasma may be generated on the semiconductor substrate. The plasma may be considered electrically grounded. The electrostatic device may be a substrate suction device of a plasma substrate processing device that processes a substrate with plasma.

[In the case of multi-layer structure or dielectric deposition on the back side of the substrate]

The operating principle of the electrostatic device having a three-layer structure according to an embodiment of the present invention will be described.

27 is a conceptual diagram illustrating the structure of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 27 , a first dielectric layer 122 , a second dielectric layer 124 , and a third dielectric layer 126 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2. The third region is formed of the third dielectric layer 126, has a third permittivity ε3 and a third electrical conductivity σ3, and has a thickness d3. The total thickness is d. The third dielectric layer 126 may be a material coated on the second electrode 120 . V0 is applied between the first electrode 110 and the second electrode 120 .

The interface surface charge density between the first dielectric layer and the second dielectric layer is ρ _sa . The interface surface charge density between the second dielectric layer and the third dielectric layer is ρ _sb . The electric field of the first dielectric is E1, the electric field of the second dielectric is E2, and the electric field of the third dielectric is E3.

The electric field (E1) of the first region, the electric field (E2) of the second region, and the electric field (E3) of the third region are given as follows when interfacial charge is ignored.

[Equation 10]

The electric fields E1, E2, and E3 may depend only on permittivity in each region in an initial state. When the thickness of the third dielectric layer 126 is relatively very thin, the electric field E3 of the third region may be the same as when the third dielectric layer 126 is not present.

The electric field E1 of the first region, the electric field E2 of the second region, and the electric field E3 of the third region are given as follows in a steady state when electrical conductivity is considered.

[Equation 11]

The electric fields E1, E2, and E3 do not depend on permittivity in each region in a steady state and may depend only on electrical conductivity. When the thickness of the third dielectric layer 126 is relatively very thin, the electric field E3 of the third region may be the same as when the third dielectric layer 126 is not present.

The surface charge density of the interface (ρ _sa , ρ _sb ) is given by

[Equation 12]

At neighboring interfaces, if the ratio of electrical conductivity is equal to the ratio of permittivity, the interfacial charge density becomes zero.

The electrostatic pressure (f) of the second electrode in the third region is given as follows.

[Equation 13]

The electric field E1 of the first region, the electric field E2 of the second region, and the electric field E3 of the third region are given as follows in a transient state.

[Equation 14]

The surface charge densities (ρsa, ρsb) of the interface are given in the transient state as:

[Equation 15]

The eigenvalue (λ) of the above equation is given by

[Equation 16]

Here, the relaxation time (τ1, τ2) is the reciprocal of the absolute value of the eigen value.

The eigenvector can be given as

[Equation 17]

The interfacial surface charge densities of an interface (ρ _sa , ρ _sb ) are given by

[Equation 18]

Applying initial conditions to the above equation, coefficient C1 and coefficient C2 can be obtained.

Accordingly, the electric fields E1 , E2 , and E3 according to time may be given by Equation 14.

[Comparison of multi-layer properties]

Case V d1=90 [um] d2=10 [um] d3=0.1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] ε3=4 [ε ₀ ] σ1=100 [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm] σ3=0.01 [10^(-12) /Ωm]

Case VI d1=90 [um] d2=10 [um] d3=0.1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] ε3=4 [ε ₀ ] σ1=10^(-4) [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm] σ3=10^(-4) [10^(-12) /Ωm]

Case VII d1=90 [um] d2=10 [um] d3=0.1 [um] ε1=10 [ε ₀ ] ε2=1 [ε ₀ ] ε3=4 [ε ₀ ] σ1=10 [10^(-12) /Ωm] σ2=1 [10^(-12) /Ωm] σ3=10^(-4) [10^(-12) /Ωm]

steady state Case V Case VI Case VII E3 4.78 [V mV/m] 0.01 [VmV/m] 10 [V mV/m] ρ _sa 0.043 [V 10^(-5)C/m^2] -0.1 [V 10^(-5)C/m^2] 0 [V 10^(-5)C/m^2] ρ _sb 19 [V 10^(-5)C/m^2] 0. 033 [V 10^(-5)C/m^2] 40 [V 10^(-5)C/m^2] τ1 10 [sec] 21 [sec] 16 [sec] τ2 668 [sec] 131,700 [sec] 66,600 [sec]

When the third dielectric layer 126 exists, the thickness d3 of the third dielectric layer is as thin as 0.1 um, but the relaxation time τ is remarkably increased. Here, the second permittivity of the second dielectric layer 124 is the permittivity of vacuum (ε0), and the second resistivity of the second dielectric layer 124 is 10^12 Ωm.

In the case of Case V, the first interfacial surface charge density (ρ _sa ) is 0.043 level and the second interfacial surface charge density (ρ _sb ) is 19 level in the steady state. Therefore, the relaxation time (τ=τ1+τ2) in the steady state has a large value of 678 seconds.

In the case of Case VI, the first interface surface charge density (ρ _sa ) is -0.1 level and the second interface surface charge density (ρ _sb ) is 0.033 level in the steady state. Therefore, the relaxation time (τ=τ1+τ2) in the steady state has a very large value of about 131,700 seconds.

In the case of Case VII, the first interface surface charge density (ρ _sa ) is 0 level and the second interface surface charge density (ρ _sb ) is 40 level in the steady state. Therefore, the relaxation time (τ=τ1+τ2) in the steady state has a very large value of about 66,600 seconds.

Case V has a relaxation time of 678 seconds and has a high interfacial charge in the steady state. Due to the relaxation time at the level of 678 seconds, a steady state may not be reached if the adsorption time (several seconds to several tens of seconds) is smaller than the relaxation time (678 seconds). Depending on the adsorption time, there is a possibility that the adsorption force is changed and unstable operation occurs. Also, during dechucking, it may not be easy to remove interfacial charges due to a large relaxation time.

In the case of having the third dielectric layer 126 having a high specific resistance, Case VI is due to a very large relaxation time (131,700 seconds), so that the static power can maintain the initial value during the adsorption time (usually several seconds to hundreds of seconds). there is. Accordingly, a stable operation can be performed.

In the case of Case VI, the interfacial charge density is relatively low in the steady state. The initial value of the third electric field E3 is 0.013, and the third electric field E3 is 0.01 in a normal state. The change is as small as about 20%. Therefore, due to the large relaxation time (131,700 seconds), the third electric field E3 in the initial state can be maintained for an adsorption time (typically several seconds to hundreds of seconds).

Case VII has the largest third electric field. When the adsorption time (several seconds to hundreds of seconds) is smaller than the relaxation time (about 66,600 seconds), the initial third electric field E3 may be used. Due to the large relaxation time, the third electric field E3 in the initial state can be maintained for an adsorption time (typically several seconds to hundreds of seconds).

In the case of the Johnson-Rabek type (Case V), in the case of having the third dielectric layer 126, in order to increase the electrostatic power by accumulating the interface surface charge density faster than the relaxation time when an external voltage is applied, other factors such as ultraviolet rays Means of accumulation of interfacial surface charge may be required.

In the case of the Johnson-Rahbek type (Case V), when the third dielectric layer 126 is provided, in order to remove the interface surface charge density faster than the relaxation time when the external voltage is removed, other interface surface charges such as ultraviolet rays are removed. Means may be required.

If the ratio of electrical conductivities in neighboring dielectrics is equal to the ratio of permittivities, the interfacial surface charge density is zero. Therefore, regardless of the relaxation time, stable adsorption and desorption operations are possible.

For example, when the material (the third dielectric layer) deposited on the rear surface of the substrate is a silicon oxide film, the second dielectric layer 124 may be a material having the same characteristics as the silicon oxide film. The first dielectric layer 122 may be an aluminum oxide film having a high dielectric constant. When the ratio of the electrical conductivity of the second dielectric layer to the first dielectric layer (σ2/σ1) is equal to the ratio of the permittivity (ε2/ε1), the interfacial charge density becomes zero. Therefore, even in a multilayer structure, interface charge can be removed.

Since the electrical conductivity of dielectrics depends on temperature, the interfacial charge can be controlled by changing the temperature.

According to a modified embodiment of the present invention, when the second dielectric layer is an air gap (or vacuum gap) and an air gap cavity is formed between the first dielectric layer and the thin third dielectric layer, the relaxation time is the characteristic of the third dielectric layer ( high third resistivity), and the third electric field may be relatively increased.

Referring to FIG. 27 , an electrostatic device 10g according to an embodiment of the present invention includes an electrostatic electrode layer 110; a first dielectric layer 122 disposed on the electrostatic electrode layer 110; a second dielectric layer (124) disposed on the first dielectric layer; a substrate (120) disposed on the second dielectric layer; and a third dielectric layer 126 disposed between the lower surface of the substrate and the second dielectric layer.

The first dielectric layer 122 has a first dielectric constant ε1 and a first electrical conductivity σ1, and the second dielectric layer 124 has a second dielectric constant ε2 and a second electrical conductivity σ2, The third dielectric layer 126 has a third permittivity ε3 and a third electrical conductivity σ3.

The ratio of the second permittivity to the first permittivity (ε2/ε1) is equal to the ratio (σ2/σ1) of the second electric conductivity to the first electric conductivity. Accordingly, the interfacial charge between the first dielectric layer 122 and the second dielectric layer 124 is zero.

The ratio of the third permittivity to the second permittivity (ε3/ε2) is equal to the ratio (σ3/σ2) of the third electric conductivity to the second electric conductivity. Accordingly, the interfacial charge between the second dielectric layer 124 and the third dielectric layer 126 is zero.

[Multi-layered serial and parallel connection structure]

28 is a conceptual diagram illustrating the structure of an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 28 , in the electrostatic device 10h, a first dielectric layer 122, a second dielectric layer 124, and a third dielectric layer 126 are formed between the first electrode 110 and the second electrode 120. are stacked. The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2. The third region is formed of the third dielectric 126, has a third permittivity ε3 and a third electrical conductivity σ3, and has a thickness d3. The total thickness is d. The third dielectric 126 may be a material coated on the second electrode 120 .

For example, the second dielectric layer 124 may be divided into three sections.

The first section may have a second main permittivity ε2 and a second main electrical conductivity σ2. The second section may have a second preliminary permittivity ε'2 and a second preliminary electrical conductivity σ'2. The third section may have the same physical characteristics as the first dielectric.

The section-by-section characteristics of the second dielectric affect the electric field of the third dielectric serially connected thereon. Accordingly, the characteristics of the third electric field of the third dielectric may be changed for each section.

For example, when only the first section and the third section are used, the first section may be an air gap. In this case, the electric field E3 of the third dielectric corresponding to the first section may be relatively increased compared to the electric field of the third dielectric corresponding to the third section.

When the third dielectric layer is deposited on the back side of the substrate, the electrostatic device needs to maintain high electrostatic power at the edge of the substrate to prevent leakage of the cooling gas flowing in the air gap. In this case, the second section may have a second preliminary permittivity ε'2 and a second preliminary electrical conductivity σ'2. When the second section is formed in a ring shape to have a low permittivity or high electrical conductivity, high electrostatic power can be provided to a position corresponding to the second section.

[Bipolar Electrostatic Device]

A bipolar electrostatic device may operate by using two electrostatic electrodes and applying a voltage between a pair of electrostatic electrodes. It is preferable that the adsorbed material has conductivity. The operating principle of a unipolar electrostatic device can be equally applied to a bipolar electrostatic device. In the case of a bipolar device having the same area and symmetry, the electrostatic power may be 1/4 for the same voltage difference compared to a unipolar device.

29 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 29 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first region is formed of the first dielectric layer 122, has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1.

The second region is formed of the second dielectric layer 124, has a second permittivity ε2 and a second electrical conductivity σ2, and has a thickness d2. The second dielectric layer may include a second preliminary dielectric layer 124'. The second preliminary dielectric layer has a second permittivity ε'2 and a second electrical conductivity σ'2, and has a thickness d2. The second dielectric layer 124 and the second preliminary dielectric layer 124' are disposed in parallel. For example, the second dielectric layer 124 may be an air gap, and the second preliminary dielectric layer 124 ′ may be made of the same material as the first dielectric layer 122 .

The first electrode 110 is an electrostatic electrode layer connected to an external power source and may include a first electrostatic electrode 110a and a second electrostatic electrode 110b disposed adjacently to form a pair. The first electrostatic electrode 110a and the second electrostatic electrode 110b may have the same area.

A first conductive layer 129a may be disposed between the first dielectric layer 122 and the second dielectric layer 124 on the first electrostatic electrode 110a. The first conductive layer 129a may be positively charged.

A second conductive layer 129b may be disposed between the first dielectric layer 122 and the second dielectric layer 124 on the second electrostatic electrode 129b. The second conductive layer 129b may be negatively charged.

The charge (+Q) charged in the first conductive layer 129a and the charge (-Q) charged in the second conductive layer 129b have different signs and may have the same value. Accordingly, when the first conductive layer 129a and the second conductive layer 129a are electrically connected to each other, charges accumulated in the first conductive layer 129a are erased and accumulated in the second conductive layer 129b. The charged charge can be erased.

A resistance layer 127 connecting the first conductive layer and the second conductive layer to each other may be disposed. The resistive layer 127 may be made of the same material as the first conductive layer and the second conductive layer, or may be made of a material whose electrical conductivity changes when light is supplied from the outside. For example, the resistive layer 127 may be CdS.

In the case of the Coulomb type, electrostatic force decreases when interfacial charges are generated. When the first conductive layer and the second conductive layer are directly connected, interfacial charges cancel each other, so that electrostatic force may be maintained in an initial state.

On the other hand, in the case of the Johnson-Rabeck type, high electrostatic force is generated by accumulating interfacial charges. After the adsorption operation is performed by accumulating interfacial charges, the resistance of the resistive layer may be reduced by light in a charge erasing step (dechucking step). Accordingly, electrical conductivity of the resistive layer 127 is changed when light is supplied from the outside, and interfacial charges may move to each other without being connected to an external circuit to reach an erased state.

Referring to FIG. 29 , an electrostatic device 10i according to an embodiment of the present invention includes electrostatic electrode layers 110a and 110b; a first dielectric layer (122) disposed on the electrostatic electrode layer; resistance layers (129a, 129b, 127) disposed on the first dielectric layer; and an air layer 124 disposed on the resistance layers 129a, 129b, and 127. The protruding portion 124' formed on the first dielectric layer 122 forms an air layer between the adsorbed material 120 and the first dielectric layer 122, and the resistance layer 127 increases electrical conductivity by light. . The resistive layers 129a, 129b, and 127 may be CdS.

The resistive layers 129a and 129b operate as layers to accumulate interfacial charge, and when light is irradiated to remove the interfacial charge, the resistive layers 129a and 129b act as conductors and the charge can be erased.

Referring to FIG. 29 , an electrostatic device 10i according to an embodiment of the present invention includes a first electrostatic electrode 110a receiving a first voltage; a second electrostatic electrode 110b receiving a second voltage; a first dielectric layer 122 disposed on the first electrostatic electrode 110a and the second electrostatic electrode 110b; a first conductive layer 129a disposed on the first dielectric layer at a position corresponding to the first electrostatic electrode 110a; a second conductive layer 129b disposed on the first dielectric layer at a position corresponding to the second electrostatic electrode 110b; and connecting the first conductive layer 129a and the second conductive layer 129b. A photoresistive layer 127; is included.

It includes an air layer 124 disposed on the first conductive layer 129a and the second conductive layer 129b, and the protrusion 124' formed on the first dielectric layer is formed between the adsorbed material and the first dielectric layer. An air layer is formed, and electrical conductivity of the photoresistive layer 127 is increased by light. That is, in the adsorption state, the photoresistive layer 127 is not irradiated with light, but in the state in which the first voltage and the second voltage are removed for desorption, the photoresistive layer 127 is irradiated with light so that the interface The charge is erased. The photoresistive layer 127 may be CdS.

30 is a conceptual diagram illustrating an electrostatic device of a typical substrate processing apparatus.

Referring to FIG. 30 , in the electrostatic device 20 , a first dielectric layer 122 and a second dielectric layer 124 are disposed between the first electrode 110 and the second electrode 120 . The second dielectric layer 124 is an air gap. In addition, the first dielectric layer 122 protrudes from the edge of the first dielectric layer 122 . The protruding portion 128 prevents gas supplied through the gas line 170 from leaking out. The second electrode 120 may be a semiconductor substrate.

However, the intensity of the electric field at the protruding portion corresponds to point A and is relatively small as a value obtained by dividing the applied voltage by the interval d. Therefore, the electric field at the protruding portion (point A) is lower than that in the gap space (point B), and the adsorption force is small due to the low electric field. Thus, gas can flow out through the protruding portion.

Even when roughening is applied to the protrusion 128, the roughening reduces the thickness of the gap space, thereby locally increasing the electric field and electrostatic force. However, stable electrostatic power cannot be provided in all areas. Further, the roughening treatment may provide a passage through which a cooling gas such as helium may flow out. On the other hand, if the roughness treatment area is increased to suppress gas leakage, the cooling performance of the gas is reduced. Also, the roughness treatment is susceptible to contamination. In addition, roughness treatment is difficult to provide stable characteristics due to abrasion.

Although the Coulomb type has been described above, a similar problem occurs in the Johnson-Rabeck type.

31 to 33 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 31 , the electrostatic device 300 includes an electrostatic electrode layer 110; a dielectric layer (122) disposed on the electrostatic electrode layer (100); and a ring-shaped protrusion 128 disposed at an edge of the dielectric layer 122 . The protrusion 128 forms a depression, and the depression is filled with a cooling gas. The protrusion 128 includes a flat area 101a and a roughened surface treatment area 101b.

The dielectric layer 122 includes an embossed area inside the protrusion 128, and the embossed area may maintain a constant distance from the second electrode or the substrate.

The strength of the electric field of the flat region 101a corresponds to point A, the electric field of the surface treatment region corresponds to point C, and the electric field of the depressed region corresponds to point B.

The roughened surface treatment region 101b provides a high electric field (electrostatic force), and the flat region 101a performs a gas sealing function to prevent gas leakage.

The flat region 101a may be disposed on the outside and the surface treatment region 101b may be disposed on the inside. Accordingly, it is possible to suppress contaminants from being deposited on the surface treatment area.

A width of the surface treatment region may be greater than a width of the flat region. Accordingly, the electrostatic force increases.

A roughness of the surface treatment region may be 0.1 um to 1 um. In the roughening treatment, the ratio (d2'/d) of the maximum height (d2') of the roughness to the total thickness (d) may be 0.001 to 0.01.

When the dielectric constant ratio (ε2/ε1) is 0.1 and the total thickness (d) of the dielectric layer is 100 um, the change in the gap (d2') according to the roughness is not large. Therefore, fine roughness processing can be easily affected by contamination.

When the total thickness (d) of the dielectric layer is 100 um, the height (d2) of the protrusion may be 5 micrometers to 20 micrometers. The height d2 of the projection may depend on the pressure of the cooling gas and the type of gas. When the height d2 of the protruding portion increases, the strength of the electric field decreases and the electrostatic force decreases. A ratio of the height d2 of the protrusion to the total thickness d of the dielectric layer may be 0.2 or less.

In the case of the Coulomb type, when the electrical conductivity ratio is considered (for example, when the electrical conductivity ratio is 10), if the ratio (d2'/d) of the maximum height of roughness (d2') is too small, the relaxation time this may decrease A small relaxation time can reduce the electric field strength with time. Accordingly, the ratio (d2'/d) of the maximum height of roughness (d2') may be 0.001 to 0.01.

Although the Coulomb type has been described above, it is similarly applied to the Johnson-Rabeck type.

In the Johnson-Rabeck type, when the electrical conductivity ratio is less than 0.1 (eg, when the electrical conductivity ratio is 0.01), referring to FIG. 5, the strength of the electric field rapidly changes according to the air gap d2'. This characteristic reduces stability depending on the surface roughness of the adsorbed object, and when the surface roughness decreases, the electric field increases and micro-discharges increase, thereby reducing stability. Meanwhile, referring to FIG. 9 , when the ratio of the maximum height (d2′/d) is 0.01 or less, the relaxation time may increase. Therefore, when a fast relaxation time is considered, the maximum height ratio (d2'/d) may be 0.01 or more. Based on d = 100um, d2' may be 1um or more.

Referring to FIG. 32 , the electrostatic device 300a includes an electrostatic electrode layer 110; a dielectric layer (122) disposed on the electrostatic electrode layer (100); and a ring-shaped protrusion 128 disposed at an edge of the dielectric layer 122 . The protrusion 128 forms a depression, and the depression is filled with a cooling gas. The protrusion 128 includes a flat area 101a and a roughened surface treatment area 101b.

The flat region 101a may be disposed on the inside and the surface treatment region 101b may be disposed on the outside.

Referring to FIG. 33 , the electrostatic device 300b includes an electrostatic electrode layer 110; a dielectric layer (122) disposed on the electrostatic electrode layer (100); and a ring-shaped protrusion 128 disposed at an edge of the dielectric layer 122 . The protrusion 128 forms a depression, and the depression is filled with a cooling gas. The protrusion 128 includes a flat area 101a and a roughened surface treatment area 101b.

The flat region 101a may include a first flat region and a second flat region, and the surface treatment region 101b may be disposed between the first flat region and the second flat region. Accordingly, a balance of forces can be maintained.

34 to 36 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 34 , the electrostatic device 400 includes an electrostatic electrode layer 110; A dielectric layer 122 disposed on the electrostatic electrode layer; and a ring-shaped first protrusion 102a disposed at an edge of the dielectric layer 122 and a ring-shaped second protruding further than the first protrusion 102a. It includes a protrusion 102b. The second protrusion or the first protrusion forms a depression, and the depression is filled with a cooling gas.

When the permittivity ratio (ε2/ε1) is 0.1, the electric field of the second protrusion 102b corresponds to point A, the electric field of the first protrusion 102a corresponds to point C, and the electric field of the depression corresponds to point B. respond Accordingly, the first protrusion may stably provide a high electric field to locally increase electrostatic force. This stepped structure is more resistant to contamination than roughness treatment and has excellent reproducibility.

The second protrusion 102b may be disposed outside to surround the first protrusion 102a. The width of the first protrusion 102a may be greater than that of the second protrusion 102a.

The height of the first protrusion 102a may be 1/2 to 19/20 of the height of the second protrusion 102b. For example, when the height of the second protrusion 102b is 10 um, the gap d2' may be 5 um to 0.5 um. If the gap d2' is too small, it may be susceptible to contamination.

When the thickness of the dielectric layer 122 is 100um, the height d2 of the second protrusion may be 5 micrometers to 20 micrometers.

Although the Coulomb type has been described above, it is similarly applied to the Johnson-Rabeck type.

Referring to FIG. 35 , the electrostatic device 400a includes an electrostatic electrode layer 110; A dielectric layer 122 disposed on the electrostatic electrode layer; and a ring-shaped first protrusion 102a disposed at an edge of the dielectric layer 122 and a ring-shaped second protruding further than the first protrusion 102a. It includes a protrusion 102b. The second protrusion or the first protrusion forms a depression, and the depression is filled with a cooling gas.

The first protrusion 102a may be disposed outside to surround the second protrusion 102b.

Referring to FIG. 36 , the electrostatic device 400b includes an electrostatic electrode layer 110; A dielectric layer 122 disposed on the electrostatic electrode layer; and a ring-shaped first protrusion 102a disposed at an edge of the dielectric layer 122 and a ring-shaped second protruding further than the first protrusion 102a. It includes a protrusion 102b. The second protrusion or the first protrusion forms a depression, and the depression is filled with a cooling gas.

The second protrusion 102a may include a second inner protrusion and a second outer protrusion spaced apart from each other. The first protrusion 102a may be disposed between the second inner protrusion and the second outer protrusion.

37 to 44 are conceptual views illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 37 , an electrostatic device 500 includes an electrostatic electrode layer; A first dielectric layer 22 disposed on the positive electrode layer; and a ring-shaped second dielectric layer 124' disposed at an edge of the first dielectric layer 122. The second dielectric layer 124' forms a recessed portion 124 in the form of an air gap. The depression is filled with cooling gas.

A cooling gas is connected to the air gap through a passage 170 penetrating the first dielectric layer 122 .

The second permittivity ε2' of the second dielectric layer 124' is smaller than the first permittivity ε1 of the first dielectric layer 122. In addition, the recessed portion is an air gap and has a second main permittivity ε2. The second permittivity ε2' of the second dielectric layer 124' is greater than the second main permittivity ε2 of the air gap.

When the dielectric constant ratio (ε2/ε1) is 0.1, the electric field of the second dielectric layer 124' corresponds to point A. Also, the electric field at the depressed area corresponds to point B. Accordingly, the electric field of the second dielectric layer 124' can be relatively increased to provide strong electrostatic power.

For example, when the first permittivity ratio ε2/ε1 is 0.1, the second permittivity ε2' of the second dielectric layer 124' is greater than the first permittivity ε1 of the first dielectric layer 122. When the second permittivity ratio (ε2'/ε1) is changed to a level of 0.4, the strength of the electric field of the second dielectric layer 124' is relatively increased. That is, the first dielectric layer is an aluminum oxide layer, the second dielectric layer 124' is a silicon oxide layer, and the second main dielectric layer 124 is an air gap. The thickness (d2) of the second dielectric layer 124' may be 0.01 to 0.2 with respect to the total thickness (d) of the dielectric.

Referring to FIG. 38, an electrostatic device 500b includes an electrostatic electrode layer; A first dielectric layer 22 disposed on the positive electrode layer; and a ring-shaped second dielectric layer 124' disposed at an edge of the first dielectric layer 122. The second dielectric layer 124' forms a recessed portion 124 in the form of an air gap. The depression is filled with cooling gas.

A cooling gas is connected to the air gap through a passage 170 penetrating the first dielectric layer 122 .

The second dielectric layer 124' has a second electrical conductivity σ2' and a second permittivity ε2'. The recessed portion 124 has a second main electrical conductivity σ2 and a second main permittivity ε2. The first dielectric layer 122 has a first electrical conductivity σ1 and a first permittivity ε1.

The second main electrical conductivity σ2 is smaller than the first electrical conductivity σ1. Also, the second electrical conductivity σ2' is smaller than the first electrical conductivity σ1.

When the electrical conductivity ratio (σ2/σ1) is 0.01, the electric field is at point A in the second dielectric layer. When the electrical conductivity ratio (σ2'/σ1) is 0.1, the electric field at the depression is point B.

Accordingly, the ring-shaped second dielectric layer 124' may have a higher electric field than that of the depressed portion (air gap). Accordingly, gas leakage is suppressed.

Referring to FIG. 39 , in the electrostatic device 500c, the second dielectric layer 124' includes a flat region 101a and a roughened surface treated region 101b. The flat region 101a may be disposed outside the surface treatment region.

In the case of the Coulomb type, when the second permittivity ε2' of the second dielectric layer 124' is reduced from the first permittivity ε1 of the first dielectric layer 122, and an air gap is formed by roughening, the strength of the electric field increases.

In the case of the Johnson-Rabek type, when the second electrical conductivity (σ2') of the second dielectric layer 124 is reduced from the first electrical conductivity (σ1) of the first dielectric layer 122, and an air gap is formed by roughening treatment. The strength of the electric field increases.

Referring to FIG. 40 , in the electrostatic device 500d, the flat region 101a may be disposed outside the surface treatment region.

In the case of the Coulomb type, when the second permittivity ε2' of the second dielectric layer 124' is reduced from the first permittivity ε1 of the first dielectric layer 122, and an air gap is formed by roughening, the strength of the electric field increases.

In the case of the Johnson-Rabek type, when the second electrical conductivity (σ2') of the second dielectric layer 124 is reduced from the first electrical conductivity (σ1) of the first dielectric layer 122, and an air gap is formed by roughening treatment. The strength of the electric field increases.

Referring to FIG. 41 , in the electrostatic device 500e, the flat region 101a may be disposed outside the surface treatment region. The second dielectric layer 124' includes a flat region 101a and a roughened surface treated region 101b. The flat region 101a may be disposed between the surface treatment regions 101b spaced apart from each other.

In the case of the Coulomb type, when the second permittivity ε2' of the second dielectric layer 124' is reduced from the first permittivity ε1 of the first dielectric layer 122, and an air gap is formed by roughening, the strength of the electric field increases.

In the case of the Johnson-Rabek type, when the second electrical conductivity (σ2') of the second dielectric layer 124 is reduced from the first electrical conductivity (σ1) of the first dielectric layer 122, and an air gap is formed by roughening treatment. The strength of the electric field increases.

Referring to FIG. 42 , an electrostatic device 500f includes an electrostatic electrode layer; A first dielectric layer 22 disposed on the positive electrode layer; and a ring-shaped second dielectric layer 124' disposed at an edge of the first dielectric layer 122. The second dielectric layer 124' forms a recessed portion 124 in the form of an air gap. The depression is filled with cooling gas.

The second dielectric layer 124' may include a first protruding region 102a and a second protruding region 102b that protrudes more than the first protruding region. The second protruding area may be disposed on the vortex of the first protruding area.

In the case of the Coulomb type, when the second permittivity ε2' of the second dielectric layer 124' is reduced from the first permittivity ε1 of the first dielectric layer 122, and an air gap is formed by step processing, the strength of the electric field increases.

In the case of the Johnson-Rabeck type, when the second electrical conductivity (σ2') of the second dielectric layer 124 is reduced from the first electrical conductivity (σ1) of the first dielectric layer 122, and an air gap is formed by step processing. The strength of the electric field increases.

Referring to FIG. 43 , referring to the electrostatic device 500g, the second dielectric layer 124' may include a first protruding region 102a and a second protruding region 102b that protrudes more than the first protruding region 102a. can The first protruding area may be disposed on the vortex of the second protruding area.

Referring to FIG. 44 , referring to the electrostatic device 500h, the second dielectric layer 124' may include a first protruding region 102a and a second protruding region 102b that protrudes more than the first protruding region 102a. can The second protrusion areas may be spaced apart from each other, and the first protrusion areas may be disposed between the second protrusion areas.

45 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 45 , in the electrostatic device 600 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first dielectric layer 122 has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second dielectric layer 124 has a second permittivity ε2 and a first electrical conductivity σ2, and has a thickness d2. The second preliminary dielectric layer 124 ′ may be made of the same material as or different from that of the first dielectric layer 122 . The second dielectric layer 124 may be an air gap or a vacuum gap.

A conductive layer 129 may be disposed between the first dielectric layer 122 and the second dielectric layer 124 . The conductive layer 129 is very thin compared to the first dielectric layer 122 or the second dielectric layer 122 . Even when the conductive layer 129 is present, the electric field and interfacial surface charge density behave the same.

The conductive layer 129 is preferably exposed to the air gap. Referring to FIG. 27 , when another dielectric layer 124 exists on the conductive layer 129 , interfacial charges are newly accumulated between the air gap 126 and the other dielectric layer 124 .

Referring again to FIG. 45 , the passage 170 provides a cooling gas to the air gap through the first dielectric layer 122 . An inner surface of the passage 170 may be coated with a conductive material.

The conductive layer 129 accumulates interfacial surface charge. Accumulated interfacial charge may be removed by being connected to the ground through the conductive material of the passage and the switch. The conductive layer 129 may be a semiconductor or a conductor. As the passage is coated with a conductive material, parasitic discharge may be suppressed.

According to a modified embodiment of the present invention, the conductive layer may be a photoresistive layer (eg, CdS). Accordingly, when light is irradiated, the resistance of the photoresistive layer is reduced so that interface deterioration can be removed to the outside.

46 is a conceptual diagram illustrating an electrostatic device according to an embodiment of the present invention.

Referring to FIG. 46 , in the electrostatic device 700 , a first dielectric layer 122 and a second dielectric layer 124 are stacked between the first electrode 110 and the second electrode 120 . The first dielectric layer 122 has a first permittivity ε1 and a first electrical conductivity σ1, and has a thickness d1. The second dielectric layer 124 has a second permittivity ε2 and a first electrical conductivity σ2, and has a thickness d2. The protruding portion 128 may be made of the same material as or a different material from that of the first dielectric layer. The second dielectric layer 124 may be an air gap or a vacuum gap.

The through hole 170 may pass through the first dielectric layer 122 and be connected to the air gap. An optical fiber 151 may be disposed in the through hole. The optical fiber 151 may provide visible light or ultraviolet light to the dielectric interface. Accordingly, the accumulated interfacial charge can be erased by visible light or ultraviolet light.

A surface of the first dielectric layer providing a lower surface of the gap space may be roughened to diffuse light.

An electrostatic device 700 according to an embodiment of the present invention includes an electrostatic electrode layer 110; dielectric layers 122 and 124 disposed on the electrostatic electrode layer; and a light providing unit 151 providing ultraviolet rays to the dielectric layers 122 and 124 . The dechucking method of the electrostatic device may include applying a first voltage (V0) to the electrostatic electrode layer; removing the first voltage applied to the electrostatic electrode layer; providing light to the dielectric layer through the light providing unit 151; and erasing electric charges accumulated on the dielectric layer or the rear surface of the substrate 120 disposed on the dielectric layer by the light.

Removing the first voltage applied to the electrostatic electrode layer and providing the light may be simultaneously performed. Accordingly, the interfacial charge disappears due to the relaxation time and also disappears due to electron-hole generation by light.

The light may be provided after removing the first voltage applied to the electrostatic electrode layer. For example, interfacial charges may first be reduced or removed by using a voltage pulse having a polarity opposite to that of the first voltage at the electrostatic electrode, and then the remaining interfacial charges may be additionally erased with light.

After removing the first voltage applied to the electrostatic electrode layer, charge of the opposite polarity is provided to the electrostatic electrode layer using a voltage pulse having a polarity opposite to that of the first voltage, and at the same time, light is irradiated to additionally erase interface charges. there is.

Although embodiments of the present invention have been described, these embodiments may be combined with each other.

Although the present invention has been shown and described with respect to specific preferred embodiments, the present invention is not limited to these embodiments, and the technical idea of the present invention claimed in the claims by those skilled in the art to which the present invention belongs It includes all of the various forms of embodiments that can be practiced within the scope of not departing from.

110: first electrode
120: second electrode
122 first dielectric
124 second dielectric

Claims (11)

an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer and having a gap space; and a power source for applying a voltage to the electrostatic electrode layer.
applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and
The dechucking method of claim 1 , wherein the power source applies a second voltage having an opposite polarity to the first voltage to erase the first interfacial charge between the gap space and the dielectric layer, thereby performing dechucking. According to claim 1,
The first voltage is V0,
The second voltage is V1,
The relaxation time is τ,
The application time (t) of the second voltage is given by

Dechucking method, characterized in that. According to claim 1,
A relaxation time defined by resistance and capacitance of the dielectric layer and the gap space is greater than an application time of the second voltage. According to claim 1,
The dechucking method of claim 1, wherein an absolute value of the second voltage is greater than an absolute value of the first voltage. According to claim 1,
The absolute value of the second voltage is equal to the absolute value of the first voltage,
The application time of the second voltage is 0.69 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. According to claim 1,
The absolute value of the second voltage is twice the absolute value of the first voltage,
The application time of the second voltage is 0.40 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. According to claim 1,
The absolute value of the second voltage is three times the absolute value of the first voltage,
The application time of the second voltage is 0.287 times the characteristic relaxation time defined by the resistance and capacitance of the gap space. an electrostatic electrode layer; a dielectric layer disposed on the electrostatic electrode layer and having a gap space; and a power source for applying a voltage to the electrostatic electrode layer.
applying a first voltage to the power source to adsorb the substrate and accumulating a first interfacial charge between the dielectric layer and the gap space; and
and a dechucking step of reducing the first interface charge by inducing a discharge in the gap space by applying a second voltage greater than the first voltage to the power source. According to claim 1,
The dechucking method of claim 1, wherein the ratio of the electrical conductivity of the gap space to the electrical conductivity of the dielectric layer is greater than the ratio of the dielectric constant of the gap space to the dielectric constant of the dielectric layer. an electrostatic electrode layer;
a dielectric layer disposed on the electrostatic electrode layer; and
A power source for applying a voltage to the electrostatic electrode layer;
The power supply adsorbs the substrate by applying a first voltage,
The electrostatic device of claim 1 , wherein the power supply performs dechucking by applying a second voltage having a polarity opposite to that of the first voltage. According to claim 10,
The first voltage is V0,
The second voltage is V1,
The relaxation time is τ,
The application time (t) of the second voltage is given by

Electrostatic device characterized in that.

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