阅读说明：本技术 薄膜沉积方法 (Thin film deposition method ) 是由 严基喆 韩政勋 金头汉 韩镕圭 柳太熙 林完奎 高东铉 于 2019-09-11 设计创作，主要内容包括：一种相对于包含图案结构的基板的薄膜沉积方法包括：通过经设置在基板下方的组件供应RF功率；在基板的暴露于反应空间的暴露表面上形成电位；使用所述电位,在反应空间中将活性物质移动到暴露表面；以及在基板的暴露表面上形成包含活性物质成分的薄膜。(A method of thin film deposition relative to a substrate containing a patterned structure comprising: supplying RF power through a component disposed below the substrate; forming an electric potential on an exposed surface of the substrate exposed to the reaction space; moving the active species to the exposed surface in the reaction space using the electrical potential; and forming a thin film containing an active material component on the exposed surface of the substrate.)

1. A thin film deposition method with respect to a substrate, the thin film deposition method comprising:

forming an electric potential on an exposed surface of the substrate exposed to a reaction space by supplying radio frequency power through a component disposed below the substrate;

moving the active species in the reaction space to an exposed surface of the substrate by using the electric potential; and

by the movement of the active material, a thin film including the active material component is formed on the exposed surface of the substrate.

2. The thin film deposition method as claimed in claim 1, further comprising increasing a density of the active species in the reaction space.

3. The thin film deposition method of claim 1, further comprising reducing mobility of the active species in the reaction space.

4. The thin film deposition method as claimed in claim 1,

wherein the exposed surface of the substrate includes an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, and

wherein the active species move at least toward a side surface of the exposed surface of the substrate.

5. The thin film deposition method of claim 2, further comprising increasing a density of the thin film by increasing an intensity of the radio frequency power.

6. The thin film deposition method of claim 1, wherein the component is a heater, and a radio frequency electrode is inserted into the heater.

7. The thin film deposition method as claimed in claim 1,

during the formation of the said electric potential(s),

wherein the substrate is disposed on a substrate supporting unit,

wherein a first portion of the substrate in contact with the substrate supporting unit is positively charged, and

wherein a second portion of the substrate opposite the first portion is negatively charged.

8. The thin film deposition method of claim 7, wherein an attractive force is generated between the second portion of the substrate and the active species.

9. The thin film deposition method as claimed in claim 1,

wherein the active species are generated from a material provided by a gas supply unit provided on the substrate, and

wherein the gas supply unit is grounded while the radio frequency power is supplied through a component disposed below the substrate.

10. The thin film deposition method as claimed in claim 1,

wherein a first plasma self-bias voltage is generated on the substrate and simultaneously a second plasma self-bias voltage is generated on the gas supply unit by supplying the radio frequency power, and

wherein the first self-bias voltage is greater than the second self-bias voltage.

11. The thin film deposition method of claim 10, wherein an exposed surface of the substrate is negatively charged by the first plasma self-bias voltage.

12. The thin film deposition method as claimed in claim 1,

wherein a bias toward the substrate is generated by supplying the radio frequency power, and

wherein the active species is moved toward the substrate at a predetermined speed by the bias.

13. The thin film deposition method of claim 12, further comprising reducing the strength of the bias.

14. The thin film deposition method of claim 12, wherein the velocity of the active species facilitates deposition on the substrate by adjusting the strength of the bias.

15. The thin film deposition method of claim 1, further comprising:

a first operation of supplying a first material; and

a second operation of supplying a second material different from the first material,

wherein the active substance is composed of the second material, and

wherein the thin film is formed by reacting the first material with the active species.

16. The thin film deposition method of claim 15, further comprising performing a purge operation at least between the first operation and the second operation.

17. The thin film deposition method of claim 1, further comprising performing isotropic etching on the thin film.

18. A thin film deposition method with respect to a substrate, the thin film deposition method comprising:

providing a pattern structure having an upper surface and a lower surface and a side surface connecting the upper surface and the lower surface;

chemisorbing a first material on the pattern structure by supplying the first material into a reaction space;

purging the first material;

supplying a second material into the reaction space;

forming a potential on the top surface, the bottom surface, and the side surface exposed to the reaction space by supplying radio frequency power through a component disposed under the substrate; and

moving the active species of the second material towards at least the side surface,

wherein a thin film is formed on a substrate by reacting the first material and the active species.

19. A thin film deposition method with respect to a substrate, the thin film deposition method comprising:

disposing a substrate on the assembly below the gas supply unit; and

forming a thin film on the substrate by supplying at least one material through the gas supply unit;

wherein the gas supply unit is grounded when the thin film is formed, and supplies radio frequency power through a component disposed under the substrate.

20. The thin film deposition method of claim 19, further comprising: while supplying the at least one material, performing at least one of the following operations:

increasing the density of the active species of the material in the reaction space;

reducing the mobility of the active species of the material in the reaction space; and

the strength of the bias formed by the rf power is reduced.

Technical Field

One or more embodiments relate to a thin film deposition method, and more particularly, to a method of depositing a thin film on a pattern structure using Plasma Enhanced Atomic Layer Deposition (PEALD).

Description of the Related Art

Plasma Enhanced Atomic Layer Deposition (PEALD) has the advantage of depositing thin films that can be deposited at high temperatures over existing thermal atomic layer depositions at low temperatures. This advantage can be achieved by introducing the reactant or source gases sequentially with a time difference, activating or ionizing at least one of the gases by plasma.

In a PEALD process, RF power is typically coupled to an upper electrode (e.g., a showerhead) located at the top of the reactor to generate a plasma in the reaction space. However, when a thin film is deposited on a pattern structure (e.g., a pattern structure having a trench) on a substrate by using plasma, characteristics of the thin film deposited on the top of the pattern directly exposed to the plasma and the thin film deposited on the walls and bottom of the trench less exposed to the plasma are not uniform.

Disclosure of Invention

One or more embodiments include a method of forming a uniform thin film on a pattern structure having a groove or a recess.

One or more embodiments include a method of depositing a thin film of uniform film quality on sidewall and bottom portions of a step of a pattern structure and improving conformality of a Wet Etch Rate (WER) during a subsequent wet etch process.

Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments presented.

According to one or more embodiments, a method of thin film deposition with respect to a substrate includes: forming an electric potential on an exposed surface of the substrate exposed to the reaction space by supplying RF power through a component disposed under the substrate; moving the active species in the reaction space to the exposed surface of the substrate by using an electric potential; and forming a thin film containing the active material component on the exposed surface of the substrate by the movement of the active material.

The thin film deposition method may further comprise increasing the density of the active material in the reaction space.

The thin film deposition method may further include reducing mobility of the active species in the reaction space.

The exposed surface of the substrate may include an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, and wherein the active species moves toward at least the side surface of the exposed surface of the substrate.

The thin film deposition method may further comprise increasing the density of the thin film by increasing the intensity of the RF power.

The component may be a heater and the RF electrode is inserted into the heater.

During the forming of the electric potential, the substrate may be disposed on the substrate supporting unit, a first portion of the substrate contacting the substrate supporting unit may be positively charged, and a second portion of the substrate opposite to the first portion may be negatively charged. In this case, an attractive force may be generated between the second portion of the substrate and the active species.

The active species may be generated by a material provided by a gas supply unit provided on the substrate, and the gas supply unit may be grounded when RF power is supplied through a component provided under the substrate.

By supplying RF power, a first plasma self-bias voltage may be generated on the substrate and a second plasma self-bias voltage may be generated on the gas supply unit at the same time, and the first self-bias voltage may be greater than the second self-bias voltage.

The exposed surface of the substrate may be negatively charged by a first plasma self-bias voltage.

By supplying RF power, a bias toward the substrate may be generated, and by the bias, the active species may be moved toward the substrate at a predetermined speed.

The thin film deposition method may further comprise reducing the strength of the bias.

By adjusting the strength of the bias, the velocity of the active species may facilitate deposition on the substrate.

The thin film deposition method may further include: a first operation of supplying a first material; and a second operation of supplying a second material different from the first material, wherein the active material is composed of the second material, and the thin film is formed by the reaction of the first material with the active material.

The thin film deposition method may further include performing a purge operation between at least the first operation and the second operation.

The thin film deposition method may further include performing isotropic etching on the thin film.

According to one or more embodiments, a method of depositing a thin film on a substrate includes: providing a pattern structure having an upper surface and a lower surface and a side surface connecting the upper surface and the lower surface; chemisorbing a first material on the pattern structure by supplying the first material into the reaction space; purging the first material; supplying a second material into the reaction space; forming a potential at a top surface, a bottom surface, and a side surface exposed to the reaction space by supplying RF power through a component disposed under a substrate; and moving the active species of the second material toward at least the side surface, wherein a thin film is formed on the substrate by reacting the first material and the active species.

According to one or more embodiments, a method of depositing a thin film on a substrate includes: disposing a substrate on the assembly below the gas supply unit; and forming a thin film on the substrate by supplying at least one material through the gas supply unit; wherein the gas supply unit is grounded when the thin film is formed, and the RF power is supplied through a component disposed under the substrate.

The thin film deposition method may further include, while supplying the at least one material, performing at least one of the following operations: increasing the density of the active species of the material in the reaction space; reducing the mobility of the active species of the material in the reaction space; and reducing the strength of the bias formed by the RF power.

Drawings

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 schematically illustrates a thin film deposition apparatus according to an embodiment of the present disclosure;

FIG. 2 schematically illustrates a thin film deposition apparatus according to an embodiment of the present disclosure;

FIG. 3 shows the change in Vdc when RF power is applied to the upper electrode and when RF power is applied to the lower electrode;

FIG. 4 schematically illustrates an active species being accelerated toward a trench structure on a substrate when RF power is supplied to the pattern structure according to the present disclosure;

FIG. 5 schematically illustrates a thin film deposition method according to an embodiment of the disclosure;

FIG. 6 is a schematic view for explaining a problem occurring in an atomic layer deposition process according to a related art;

FIG. 7 shows deposited SiO when RF power is supplied through a lower electrode using a Plasma Enhanced Atomic Layer Deposition (PEALD) method according to embodiments of the disclosure₂Etch resistance of the film;

FIG. 8 schematically illustrates a thin film deposition method according to an embodiment of the present disclosure;

FIG. 9 schematically illustrates a thin film deposition method according to an embodiment of the present disclosure; and

fig. 10 to 13 illustrate the substrate supporting unit according to an embodiment of the present disclosure in more detail.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as limiting the description set forth herein. Accordingly, the embodiments are described below to explain aspects of the description by referring to the figures only. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Such as "at least one of …," when following a list of elements, modifies the entire list of elements rather than modifying individual elements within the list.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

The embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art, the following embodiments may be modified into various other forms, and the scope of the present disclosure is not limited to the following embodiments. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. In addition, the term "comprises (comprising)" when used in this specification specifies the stated shapes, numbers, steps, operations, means, elements and/or combinations thereof, but does not preclude the presence or addition of one or more other shapes, numbers, steps, operations, means, elements and/or combinations thereof. As used herein, the term "and/or" can encompass any and all combinations of one or more of the associated listed items.

Although terms such as "first" and "second" may be used herein to describe various elements, regions and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are not intended to imply a particular order, priority, or precedence, but are merely used to distinguish one element, region, and/or section from another. Thus, a first member, a first region, and/or a first portion to be described below may refer to a second member, a second region, and/or a second portion without departing from the teachings of the present disclosure.

In the present disclosure, "gas" may comprise vaporized solids and/or liquids, and may comprise a single gas or a mixture of gases. In the present disclosure, the process gas introduced into the reaction chamber through the gas supply unit may contain a precursor gas and an additive gas. The precursor gas and the additive gas may typically be introduced as a mixed gas and may be introduced separately into the reaction space. The precursor gas may be introduced together with a carrier gas, such as an inert gas. The additive gas may comprise a diluent gas such as a reactant gas and an inert gas. The reactant gas and the diluent gas may be introduced into the reaction space either mixedly or separately. The precursor may comprise two or more precursors and the reactant gas may comprise two or more reactant gases. The precursor may be a gas that is chemisorbed onto the substrate and typically contains a non-metallic (metalloid) or metallic element that constitutes the primary structure of the matrix of the dielectric film, and the reactant gas for deposition may be a gas that, when excited, reacts with the precursor chemisorbed onto the substrate to fix the atomic layer or monolayer on the substrate. The term "chemisorption" may refer to chemically saturated adsorption. Gases other than the process gas, that is, gases that do not need to be introduced through the gas supply unit, may be used to seal the reaction space, and may contain a sealing gas such as an inert gas. In some embodiments, the term "film" may refer to a layer that extends continuously perpendicular to the thickness direction with substantially no pinholes to cover the entire target or associated surface, or may refer to a layer that readily covers the target or associated surface. In some embodiments, the term "layer" may refer to a structure of a film, or a synonym for a film, or a non-film structure having any thickness formed on a surface. A film or layer may comprise a discrete single film or layer or a plurality of films or layers having some property, and the boundaries between adjacent films or layers may or may not be clear and may be set based on physical, chemical, and other properties, formation processes or order of formation, and/or the function or use of adjacent films or layers.

In the present disclosure, the expression "same material" should be understood to mean that the main components (ingredients) are the same. For example, when the first layer and the second layer are both silicon carbide layers and are formed of the same material, the first layer may be selected from the group consisting of Si₂N、SiN、Si₃N₄And Si₂N₃A combination of constituents, and the second layer may also beSelected from the combinations above, but the specific film quality of the second layer may be different from the film quality of the first layer.

Further, in the present disclosure, the respective operable ranges may be determined based on routine work, any two variables may constitute the operable ranges of the variables and any indicated range may include or exclude endpoints. Further, the values of any indicated variable may refer to exact or approximate values (whether they are indicated as "about"), may encompass equivalent values, and may refer to average, median, representative, multiple, or the like.

In the case where conditions and/or structures are not specified in the present disclosure, those of ordinary skill in the art can easily provide these conditions and/or structures according to the present disclosure as a matter of general experiments. In all described embodiments, any component used in the embodiments may be replaced with any equivalent component thereof, including the components explicitly, necessarily and substantially described herein, for which the disclosure may be advantageously applied to apparatuses and methods for the intended purpose and in addition.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, variations in shape from that shown may be expected, for example, due to manufacturing techniques and/or tolerances. Accordingly, embodiments of the present disclosure should not be construed as limited to the shapes of regions illustrated herein but may include deviations in shapes that result from manufacturing processes.

Fig. 1 schematically illustrates a thin film deposition apparatus according to an embodiment of the present disclosure. As an example of the thin film deposition apparatus described in this specification, there may be a deposition apparatus of a semiconductor or a display substrate, but the present disclosure is not limited thereto. The thin film deposition apparatus may be any apparatus required for depositing a material to form a thin film.

Referring to fig. 1, the thin film deposition apparatus may include a partition wall 110, a gas supply unit 120, a substrate support unit 130, and an exhaust passage 140.

The partition wall 110 may be a component of a reactor in the thin film deposition apparatus. In other words, the reaction space for deposition on the substrate may be formed by the partition wall 110 structure. For example, the partition wall 110 may comprise a reactor side wall and/or a reactor top wall. The top wall of the reactor in the partition wall 110 may provide a gas supply passage 150 through which a source gas, a purge gas, and/or a reactant gas may be supplied.

The gas supply unit 120 may be disposed on the substrate support unit 130. The gas supply unit 120 may be connected to the gas supply passage 150. The gas supply unit 120 may be fixed to the reactor. For example, the gas supply unit 120 may be fixed to the partition wall 110 via a fixing member (not shown). The gas supply unit 120 may be configured to supply gas to an object to be processed in the reaction space 160. For example, the gas supply unit 120 may be a showerhead assembly.

A gas flow channel 170 communicating with the gas supply channel 150 may be formed in the gas supply unit 120. The gas flow channel 170 may be formed between the gas channel 125 (upper portion) of the gas supply unit 120 and the gas supply plate 127 (lower portion) of the gas supply unit 120. Although the gas channel 125 and the gas supply plate 127 are illustrated as separate structures in the drawings, the gas channel 125 and the gas supply plate 127 may also be formed as an integrated structure.

The substrate supporting unit 130 may be configured to provide a space for a substrate to be accommodated and contact a lower surface of the partition wall 110. The substrate supporting unit 130 may be supported by the main body 200. The main body 200 may move up and down and rotate. The reaction space 160 may be opened or closed by moving the substrate support unit 130 away from the partition wall 110 or contacting the partition wall 110 by the up and down movement of the main body 200.

The substrate support unit 130 may further include a heater 310 and an RF electrode 320.

The heater 310 may be formed to penetrate at least a portion of the substrate support unit 130. The heater 310 may be disposed under a substrate (i.e., inside the substrate supporting unit 130) accommodated on the substrate supporting unit 130. The temperature of the substrate placed on the substrate supporting unit 130 and/or the temperature of the reaction space may be increased by heating the heater 310. The heater 310 may have a shape (e.g., a circular plate) formed as a plate corresponding to the shape of the substrate, or may have a shape of a rod disposed symmetrically with respect to the substrate.

The RF electrode 320 may penetrate at least a portion of the substrate support unit 130. The RF electrode 320 may be disposed under a substrate (i.e., inside the substrate supporting unit 130) accommodated on the substrate supporting unit 130. RF power can be delivered to reaction space 160 through RF electrode 320 and, accordingly, plasma can be generated in reaction space 160.

The RF electrode 320 may be disposed between a substrate to be processed and the heater 310. That is, the RF electrode 320 may be disposed on the heater 310 such that RF power may be transmitted to the substrate without being blocked by the heater 310. An insulating material may be disposed between the heater 310 and the RF electrode 320. In an alternative embodiment, the insulating material may comprise aluminum nitride. In another alternative embodiment, the insulating material may be a low dielectric constant material such as air. That is, an air gap may be formed between the heater 310 and the RF electrode 320.

The shape of RF electrode 320 may correspond to the shape of the substrate. For example, when the substrate has a disk shape, the RF electrode 320 may be formed to have a disk shape. In another example, RF electrode 320 can have the shape of a rod that is symmetrically disposed with respect to the substrate. In an alternative embodiment, a metal portion connected to ground may be additionally disposed between the RF electrode 320 and the heater 310. The shape of the metal portion may correspond to the shape of RF electrode 320 and/or the shape of heater 310.

By supplying RF power from RF electrode 320, an electric potential (e.g., a negative electric potential) can be formed on the substrate exposed to the reaction space. For example, the substrate supporting unit 130 may be connected to a plasma generating unit (not shown), RF power generated by the plasma generating unit may be delivered to the substrate within the reaction space by the RF electrode 320, and thus plasma may be generated in the reaction space.

More specifically, by the RF power supply, a first plasma self-bias voltage may be generated on the substrate, and a second plasma self-bias voltage may be generated on the gas supply unit 120. In this case, since the substrate supporting unit 130 under the substrate is connected to the RF generator (not shown in fig. 1, see fig. 2) while the gas supplying unit 120 is connected to the ground, the first plasma self-bias voltage may be greater than the second plasma self-bias voltage. Thus, the exposed surface of the substrate may be negatively charged by the first plasma self-bias voltage.

By the formation of the plasma, a sheath (sheath) potential may be formed on a portion of the substrate exposed to the reaction space. Such sheath potentials may generally cause sputtering. The related art uses a Reactive Ion Etching (RIE) process or a Physical Vapor Deposition (PVD) process to perform deposition using such a sputtering phenomenon. On the other hand, it is noted that the present disclosure is distinguished from the related art in that: the thin film containing the active material component is directly deposited on the substrate using the active material having the reduced mobility, rather than reducing the sputtering by the sheath potential.

Referring back to fig. 1, the body 200 (which is a component of the substrate support unit 130) below the substrate support unit 130 may include a first rod 410, a second rod 420, and an RF shield 430. The heater 310 may be connected to the first rod 410. The RF electrode 320 may be connected to a second rod 420. At least a portion of the RF shield 430 may be disposed between the first rod 410 and the second rod 420. More specifically, the RF shield 430 may be spaced apart from the second rod 420 and disposed to surround the second rod 420. The RF shield 430 may also extend in the extending direction of the second rod 420.

The RF shield 430 may block an influence between a first signal transmitted to the heater 310 through the first rod 410 and a second signal transmitted to the RF electrode 320 through the second rod 420. To this end, the RF shield 430 may be connected to ground, for example. In another alternative embodiment, a first insulating member 440 may be disposed between the second rod 420 and the RF shield 430. The first insulating member 440 may have a ring shape, and may include a through hole through which the second rod 420 passes. The relative positional relationship between the second rod 420 and the RF shield 430 may be fixed by the first insulating member 440.

Although not shown in the drawings, the thin film deposition apparatus may further include a power supply unit configured to supply power to the heater 310. The power supply unit may be connected to the first lever 410. In an alternative embodiment, the first low-pass filter may be disposed between the first rod 410 and a power supply unit (not shown in fig. 1) (see fig. 9). Furthermore, in additional embodiments, the film deposition apparatus may further include a thermocouple and a temperature control unit. The thermocouple may be connected to the heater 310 and configured to generate an electrical signal in response to a change in temperature of the heater 310. The generated electrical signal may be transmitted to a temperature control unit. The temperature control unit may be configured to control the power supply unit based on the electrical signal. In an alternative embodiment, a second low pass filter electrically connected to the thermocouple may also be provided. The first and second low pass filters may prevent the RF power signal for applying the plasma from affecting the power supply unit and the temperature control unit. The configuration as described above will be described in more detail later with reference to fig. 9.

In addition, although not shown in the drawings, the substrate supporting unit 130 may further include a socket and a ground bracket. The second rod 420 and the plasma generating unit (not shown) may be connected through a socket. In addition, the RF shield 430 and ground may be connected by a grounding bracket. The second insulating member may be disposed between the socket and the ground bracket, and may prevent electrical connection between the socket and the ground bracket through the second insulating member. In addition, the receptacle and the ground bracket may be mechanically fixed by the second insulating member.

In addition, a fixing unit may be included in the main body 200 of the substrate support unit 130 so that a portion of the RF shield 430 may be fixed. The main body 200 may be disposed to surround the fixing unit and support the fixing unit. Accordingly, the position of the RF shield 430 may be fixed by the main body 200 and the fixing unit. In an alternative embodiment, the body 200 may be spaced apart from the RF shield 430 and the ground bracket. The configuration of the receptacle, the ground bracket, and the fixing unit will be described later in more detail with reference to fig. 10.

Fig. 2 schematically illustrates a thin film deposition apparatus according to an embodiment of the present disclosure. The thin film deposition apparatus according to the embodiment may be a modification of the thin film deposition apparatus according to the embodiment described above. Hereinafter, redundant description of the embodiments will be omitted.

In the substrate supporting unit of fig. 1, the RF electrode may be formed to surround the heater, and the RF electrode 320 of fig. 2 may be formed to be inserted into the substrate supporting unit 130. In fig. 1, the reaction space may be formed by sealing the surfaces of the partition wall 110 and the substrate support unit 130, and in fig. 2, the reaction space may be formed by the first cover 240 and the second cover 250. However, it is to be noted that the present disclosure is not limited to these shapes, and various modifications other than those described in fig. 1 and 2 are possible.

Referring to fig. 2, the thin film deposition apparatus may include a first cover 240 providing the partition wall 110 and the exhaust passage 140, a second cover 250 providing the gas supply unit 120, and the substrate support unit 130. The bottom of the reaction space 160 may be formed by the substrate supporting unit 130, the top of the reaction space 160 may be formed by the second cover 250, and both sides of the reaction space 160 may be formed by the first cover 240.

The exhaust structure of the substrate processing apparatus may be configured as a downstream exhaust structure. Meanwhile, the downstream exhaust structure may be implemented by the first cover 240. In this case, the gas for deposition may be supplied to the substrate to be processed through the showerhead of the second cover 250 and then exhausted downstream through the exhaust passage 140 of the first cover 240.

As described above, in the present embodiment, the RF electrode 320 may be inserted into the substrate supporting unit 130. In addition, a heater (not shown) may also be inserted into the substrate supporting unit 130. An insulating material may be disposed between the heater and RF electrode 320 to prevent an electrical connection between RF electrode 320 and the heater.

The thin film deposition apparatus may further include a plasma supplier P and a ground G. The plasma supplier P may include an RF generator RG and a matcher MC.

The RF generator RG may output a frequency signal suitable for controlling the energy of the active species and/or ions applied to the substrate in the reaction space. The signal may have a high frequency of, for example, 13.56MHz, and preferably a Very High Frequency (VHF) band of 30MHz or higher, more preferably a Very High Frequency (VHF) band of 60MHz or higher.

The matcher MC may comprise a matching circuit to match between the impedance of the RF generator RG and the impedance on the load side (e.g. electrodes, reaction space, etc.). In addition to the matching circuit, the matcher MC may comprise at least one of: an RF sensor to measure load impedance, a controller to variably adjust the value of the variable reactance device (impedance position) in the matching circuit, a stepper motor, and a cooling fan. In another example, the matcher MC may also include a blocking capacitor (blocking capacitor) that generates the magnetic bias.

As shown in fig. 2, in the present disclosure, RF power may be supplied through the lower electrode instead of the upper electrode such as the showerhead. For example, the RF electrode 320 may be inserted into the substrate supporting unit 130 or the heater block to supply RF power into the reaction space from the bottom of the reactor. By exciting the reactant gas by RF power, a plasma can be generated in the reaction space, particularly on the substrate. In other words, by supplying RF power through the substrate supporting unit (or the heater block) below the reactor, radicals in the reaction space may be accelerated toward the bottom (i.e., the substrate) rather than the top of the reactor (i.e., the gas supply unit 120).

Fig. 3 shows the change in Vdc when RF power is applied to the upper electrode UE (left side) and when RF power is applied to the lower electrode LE (right side). Vdc in fig. 3 may be the plasma self-bias voltage and determines the directionality of ions and radicals. In other words, ions and radicals can be accelerated and move along with the larger Vdc.

First, when RF power is supplied through the upper electrode UE, that is, a configuration (e.g., a gas supply unit) opposite to a portion on which the substrate is placed, because Vdc in the upper electrode UE such as the gas supply unit (e.g., a showerhead assembly) is greater than Vdc in the lower electrode LE such as the substrate support unit, ions and radicals may be accelerated in a direction opposite to a direction toward the substrate. A typical plasma deposition process may be performed using ions and/or radicals that move as described above.

On the other hand, according to the technical concept of the present disclosure, RF power may be supplied through the lower electrode LE (that is, a component, such as a heater, under the substrate supporting unit on which the substrate is placed). In this case, Vdc in the lower electrode LE such as the substrate support unit may be higher than Vdc in the upper electrode UE such as the gas supply unit, and thus ions and radicals may be accelerated toward the substrate. Reactive species accelerated toward the substrate may collide with the substrate to cause etching of substrate surface material rather than deposition. Accordingly, the mobility of the active species may be adjusted or reduced so that the active species accelerated toward the substrate may contribute to deposition on the substrate rather than etching.

As an example of reducing the mobility of the active species, Very High Frequency (VHF) RF power may be supplied through the lower electrode LE in the present disclosure. The VHF may have a frequency greater than 30MHz and a frequency of 100 MHz. Since Vdc of VHF is low, the energy accelerated by the plasma sheath can be small. Therefore, the acceleration by the sheath layer may contribute more to deposition rather than damage to the thin film, and accordingly the density of the thin film may be increased.

In alternative embodiments, more reactive species may be generated such that the reactive species accelerated toward the substrate may facilitate deposition on the substrate rather than etching. For example, by supplying VHF RF power through the lower electrode LE, more active species can be generated in the reaction space. In addition, the formation of a thin film may be facilitated by accelerating more active species toward the substrate.

In another alternative embodiment, the movement energy and/or acceleration energy of the reactive species may be reduced such that the reactive species accelerated toward the substrate may facilitate deposition on the substrate rather than etching. For example, by reducing the plasma self-bias voltage Vdc generated during plasma application, the velocity and/or acceleration of the active species may be reduced.

As described above, the present disclosure may introduce a configuration of at least one among the following configurations: a configuration of increasing the amount of active species in the reaction space, a configuration of decreasing the mobility of active species in the reaction space, and a configuration of decreasing the magnitude of the bias formed by the RF power; while the lower electrode LE RF application configuration used in the related art sputtering and/or etching was applied to the plasma enhanced atomic layer process. This can improve the conformality of the thin film deposited on the trenches of the pattern structure of the complex structure. Thus, a high density plasma ALD process may be achieved, which may minimize damage to materials on the substrate.

Fig. 4 schematically illustrates active species being accelerated toward a trench structure on a substrate when RF power is supplied to the pattern structure according to the present disclosure. In fig. 4, nitrogen is used as the reaction gas, but it is noted that the technical idea of the present disclosure is not limited thereto. For example, the technical idea of the present disclosure may be applied to the deposition of oxide or other multi-component thin films other than nitride.

Referring to fig. 4, in order to form plasma in the reaction space, RF power may be applied through the RF electrode 320 included in the substrate support unit 130, and the RF electrode 320 may be negatively charged by the application of the RF power. Therefore, the surface (metal surface or non-metal surface) of the substrate supporting unit 130 may also be negatively charged. In this case, the first portion S1 of the substrate S in contact with the substrate supporting unit 130 may be positively charged. On the other hand, the second portion S2 of the substrate S, which is opposite to the first portion S1, may be negatively charged.

The second portion S2 may be exposed to a portion of the reaction space, and a pattern structure having a top surface, a bottom surface, and a side surface connecting the top and bottom surfaces may be formed in the second portion S2. An attractive force may occur between the negatively charged second part S2 and the positively charged active species, and thus the active species may move toward the top, bottom, and sides of the pattern structure.

As described above, according to the embodiments of the technical idea of the present disclosure, a deposition process may be performed using not only the active species moved or accelerated by the plasma sheath but also the attractive force generated between the surface (particularly, the side surface and the bottom surface) and the active species by the pattern structure that charges the pattern structure. Accordingly, a high-quality thin film may be deposited on the side and bottom surfaces of a structure including a trench or a recess having a high aspect ratio (aspect ratio).

Fig. 5 schematically illustrates a thin film deposition method according to an embodiment of the present disclosure. The thin film deposition method according to the embodiment may be performed using the thin film deposition apparatus according to the embodiment as described above. Hereinafter, redundant description of the embodiments will be omitted.

Referring to fig. 5, in order to perform thin film deposition on a substrate, a potential (e.g., a negative potential) may be first formed on an exposed surface of the substrate disposed in a reaction space (0510). To this end, RF power may be supplied through components disposed under the substrate, such as a substrate support unit, a susceptor (suscepter), and/or a heater. By supplying RF power, a sheath potential can be formed on the exposed surface of the substrate.

For example, when the component is a heater, the RF electrode can be inserted into the heater. As another example, the component may be a substrate support unit, and the heater and the RF electrode may be inserted into the substrate support unit. As another example, the component may be a metal susceptor, and the heater may be inserted into the metal susceptor.

In an alternative embodiment, the active species may be generated from a material provided by a gas supply unit provided on the substrate before the RF power is supplied. In addition, the substrate supporting unit may be connected to the RF generator while the RF power is being supplied, and the gas supply unit may be grounded.

Thereafter, the potential can be used to move the active species in the reaction space to the exposed surface of the substrate (0520). For example, a positively charged active species in the reaction space may be accelerated and moved from the sheath potential toward the substrate. However, as described above, the velocity and/or acceleration of the active species may be adjusted by changing the parameters of the RF power or the like so that the active species may not damage the pattern structure on the substrate.

The mobile active species described above can facilitate thin film deposition on patterned structures (0530). Therefore, a thin film containing an active material component can be formed on the exposed surface of the reaction space.

In some embodiments, the exposed surface of the substrate may include an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, and the active species may move at least toward the side surface. The movement of the active species toward the side surface and toward the lower surface may improve the conformality of the thin film deposited on the pattern structure having the recesses and the grooves. In the case of a thin film having improved conformality, the thickness of the remaining film may be constant although isotropic etching is performed after deposition on the pattern structure.

In some other embodiments, an operation of increasing the amount of the active material in the reaction space may be performed so that a thin film containing an active material component may be formed. The larger the amount of the active material in the reaction space, the smaller the average traveling distance the active material can travel, and the lower the average velocity of the active material. The active species having a reduced speed may contribute to thin film formation rather than damage (sputtering) to the pattern structure.

In another alternative embodiment, an operation of reducing the mobility of the active material in the reaction space may be performed so that a thin film containing the active material component may be formed. For example, when the frequency of the RF power is increased, the direction of increasing the active material according to the increased frequency is changed, resulting in a decrease in mobility of the active material. The active species having reduced mobility may contribute to thin film formation rather than damage (sputtering) to the pattern structure.

In another alternative embodiment, an operation of reducing the strength of the bias may be performed so that a thin film containing an active material component may be formed. When RF power is applied, a bias towards the substrate (i.e., a plasma self-bias) may be generated, which causes the reactive species to move towards the substrate at a predetermined velocity and/or to accelerate at a predetermined acceleration. In this case, the strength of the bias may effect the movement and/or acceleration, and the movement energy and/or acceleration energy of the active substance may be reduced by reducing the strength of the bias. By adjusting the strength of the bias, the velocity of the active species may facilitate deposition of the active species on the substrate.

In some embodiments, increasing the intensity of the RF power may be performed to increase the density of the deposited thin film. Increased intensity of RF power can result in the generation of more reactive species. That is, more active species can be accelerated toward the substrate, and thus a denser and harder film can be formed.

In some other embodiments, the thin film deposition process may be performed using an atomic layer deposition process and a periodic chemical vapor deposition process. For example, when the thin film deposition method is performed, a first operation of supplying a first material and a second operation of supplying a second material different from the first material may be performed. Active substances used in the present disclosure may be composed of a first material and/or a second material. When the active material is composed of the second material, a thin film may be formed by a reaction of the first material and the active material. In some other embodiments, the thin film deposition method may include a purge operation performed at least between the first and second operations.

Fig. 6 is a schematic view for explaining a problem occurring in an atomic layer deposition process according to the related art. In the left side of fig. 6, a thin film 20 may be deposited on the patterned structure 10 by using a PEALD method. For example, when the binary compound is formed, a source gas and a reactant gas may be sequentially supplied at a time interval, and at least one of the two gases may be activated by plasma to induce a chemical reaction between the gases and deposit a thin film on the pattern structure. Because the thin films are sequentially stacked layer by layer, the thin films having conformality can be uniformly deposited over the top, sides, and bottom of the trench structure.

Thereafter, the wet etching may be continued in a subsequent process. As shown on the right side of fig. 6, it can be seen that the degree of conformality of the residual film a on the top of the pattern structure and the residual film B on the side and bottom of the pattern structure trench is not constant (a ≠ B). This is one of the problems in the related art due to the linearity of plasma ions and radicals. The film deposited on top of the pattern perpendicular to the direction of travel of the plasma ions can be densified due to the effect of ion bombardment. However, in the case of the sides and bottom of the trench, the effect of ion bombardment by radicals may be less than the top of the trench, the radicals may have difficulty reaching the bottom of the trench, and thus may not be as dense as the top film. Therefore, on the basis of the wet etching, a Wet Etching Rate (WER) of a film formed on the side and bottom of the trench may be greater than that of a film formed on the top of the trench.

One of the objectives of the thin film deposition method of the present disclosure is to solve the above-mentioned problems. That is, the present disclosure provides a method of maintaining conformality of a thin film uniformly formed on a pattern after deposition even after continuing wet etching.

For this, in the present disclosure, a substrate may be disposed under the gas supply unit, and at least one material may be supplied as a component for forming a thin film through the gas supply unit to form the thin film on the substrate. The gas supply unit may be grounded during an operation of forming the thin film, and RF power may be supplied through a component disposed under the substrate. At least one of the following operations may be performed such that the plasma generated by the RF power may facilitate deposition, the operations comprising: increasing the density of the active species in the reaction space, decreasing the mobility of the active species, and decreasing the intensity of the bias formed by the RF power. Accordingly, a thin film having improved conformality may be formed on the pattern structure. In addition, by accelerating more radicals towards the substrate, a thin film can be deposited on the surface of the pattern structure, which is denser and has improved etch resistance.

Fig. 7 illustrates deposited SiO when RF power is supplied through a lower electrode using a Plasma Enhanced Atomic Layer Deposition (PEALD) method (see "BTM (bottom) bias" of fig. 7) according to an embodiment of the present disclosure₂Etch resistance of the film. The experiment was performed on a flat substrate. The Si precursor is Bisdiethylaminosilane (BDEAS) and Trisdimethylaminosilane (TDMAS). Oxygen plasma is used as the reaction gas. The RF power frequency is set at 60 MHz.

Referring to FIG. 7, it can be appreciated that the WER is about 86 to 87 when 800W of RF power is supplied through the lower electrode, and SiO when 800 Watts of RF power is supplied through the upper electrode₂The WER of the film is about 91.7, and the RF power through the lower electrode shows a lower WER than through the upper electrodeRF power of (c) shows WER. This is because more active species are accelerated toward the substrate by a lower bias, thereby forming a denser and stiffer film. Referring to fig. 7, it can be appreciated that when RF power is supplied through the lower electrode (see "BTM bias" of fig. 7), WER decreases as RF power increases. For example, by supplying RF power having a VHF frequency of 60MHz or more but supplying RF power of at least 800W, a denser film can be formed.

Fig. 8 schematically illustrates a thin film deposition method according to an embodiment of the present disclosure. The thin film deposition method according to the embodiment may be a modification of the thin film deposition method according to the embodiment described above. Hereinafter, redundant description of the embodiments will be omitted.

Referring to fig. 8, a pattern structure having an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface may be first introduced into a reaction space. Subsequently, during a period from t0 to t1, a first material (e.g., a silicon precursor) may be supplied into the reaction space such that the first material chemisorbs onto the pattern structure. During the time period from t1 to t2, the residue of the first material may be purged. As shown in fig. 8, the purge gas may flow throughout the process cycle. During the time period from t2 to t3, a second material (e.g., oxygen) may be supplied into the reaction space. During the period from t2 to t3, RF power may be supplied through components disposed under the substrate to form electric potentials on the upper and lower surfaces and the side surfaces exposed to the reaction space. During a period from t2 to t3, the active species of the second material may move by the potential at least toward the side surface, and the chemisorbed first material may react with the active species to form a thin film on the substrate. During the time period from t3 to t4, the residue of the second material (and active species) may be purged. A series of operations performed during the period from t0 to t4 may be defined as one cycle, and the cycle may be repeated a plurality of times.

The following Table 1 shows SiO using the embodiment of FIG. 8₂Experimental conditions for thin film deposition. As experimental conditions for exemplary embodiments, TDMAS was used as a silicon source and as shown in Table 1 belowOxygen is used as the reaction gas.

Although TDMAS is used as the Si source in table 1 above, the present disclosure is not limited thereto. For example, the Si source may comprise at least one of: iodosilane containing TSA, (SiH)₃)₃N；DSO，(SiH₃)₂；DSMA，(SiH₃)₂NMe；DSEA，(SiH₃)₂NEt；DSIPA，(SiH₃)₂N(iPr)；DSTBA，(SiH₃)₂N(tBu)；DEAS，SiH₃NEt₂；DIPAS，SiH₃N(iPr)₂；DTBAS，SiH₃N(tBu)₂；BDEAS，SiH₂(NEt₂)₂；BDMAS，SiH₂(NMe₂)₂；BTBAS，SiH₂(NHtBu)₂；BITS，SiH₂(NHSiMe₃)₂；TEOS，Si(OEt)₄；SiCl₄；HCD，Si₂Cl6；DCS，SiH₂Cl₂；3DMAS，SiH(N(Me)₂)₃；BEMAS，Si H₂[N(Et)(Me)]₂；AHEAD，Si₂(NHEt)₆；TEAS，Si(NHEt)₄；Si₃H₈(ii) a And at least one of iodosilane, diiodosilane and pentaiodosilane, for example comprising Si-H. In addition, the oxygen-containing gas as the reaction gas is other than O₂May contain O in addition₃、N₂At least one of O and NO. In another embodiment, by supplying at least one such as N₂、NH₃And NH₄ ⁺The nitrogen-containing reactant gas may deposit silicon nitride on the substrate. In addition, various types of thin films can be formed.

In table 1 and fig. 8, the Si source gas and the oxygen reactant gas may be subsequently supplied at time intervals in sequence. The oxygen reaction gas can be activated by RF powerReacting with Si source to form SiO on the substrate₂A film. RF power may be supplied to the lower electrode, that is, the RF electrode 320 embedded in an electric heater as described above. Accordingly, plasma may be generated in the reaction space on the substrate by the components below the substrate. In particular, high frequency RF power of 60MHz may be supplied according to the present disclosure, and thus more radicals may be supplied to the trench structure of the pattern structure. Thus, films with subsequently improved etch characteristics (i.e., uniform and low WER during subsequent isotropic etching) can be deposited.

The following table 2 shows the variation of the etching characteristics of the films deposited on the pattern structure according to the above table 1 and fig. 8.

Table 2 compares SiO in a trench structure according to an upper plasma applying method of the related art and a lower plasma applying method according to the present disclosure₂WER characteristics of the film. As can be seen from table 2 above, it can be understood that the WER of each part in the trench is reduced by 20% in the lower plasma application method compared to the upper plasma method. That is, the density of the thin film deposited in the trench may be increased and the etch resistance may be improved. Experimental results it can be understood that plasma is generated in the reaction space by supplying VHF RF power through the lower electrode according to the present disclosure, and thus more radicals are accelerated toward the substrate and a dense film having improved etch resistance can be deposited on the inner surface of the trench.

Fig. 9 schematically illustrates a thin film deposition method according to an embodiment of the present disclosure. The thin film deposition method according to the embodiment may be a modification of the thin film deposition method according to the embodiment described above. Hereinafter, redundant description of the embodiments will be omitted.

Referring to fig. 9, the RF electrode 320 may be embedded below the upper surface of the substrate supporting unit 130 on which the substrate is mounted, and RF power from the RF plasma applying unit P may be supplied through the second rod 420 as an RF rod. The RF plasma applying unit P may include an RF signal generator and a matcher (matching network) (see fig. 2). The substrate supporting unit 130 may further include a heater 310 supplying heat to the substrate. The heater 310 may be a heating element having a high resistance, and may receive current from the power supply unit 710 through the first rod 410 as a power rod. One side of the heater 310 may be connected to a thermocouple 450. The temperature control unit 720 may compare the actual temperature of the heater 310 measured by the thermocouple 450 with a set temperature and control the current supply of the power supply unit 710.

As described above, the RF shield 430 may be mounted on the substrate support unit 130 or in a thin film deposition apparatus including the substrate support unit 130 according to the technical concept of the present disclosure, and may be disposed around the RF rod 420. The RF shield 430 may prevent parasitic plasma from being generated under the substrate support unit 130 due to the RF current supplied through the RF rod 420. In addition, the RF shield 430 may block cross-talk effects, where RF currents affect the power rod 410 and power supply unit 710, etc. around it. The RF shield 430 may comprise aluminum and may be mounted to allow temperature control and stable current supply to the heater 310.

In an alternative embodiment, the first low pass filter LPF1 disposed between the first rod 410 and the power supply unit 710 may be configured to pass signals generated by the plasma generation unit having a frequency band lower than the frequency of the RF power. For example, when the frequency band of the RF power is 60MHz, the first low pass filter LPF1 may be configured to pass only signals having a frequency band less than 60 MHz. The crosstalk may cause an RF power signal of 60MHz or more generated by the plasma generating unit to be delivered to a channel connected to the power supply unit 710 (e.g., a connection line between the first rod 410 and the power supply unit 710). In this case, the signal components (i.e., the RF power signals) in the channels may be blocked by the first low pass filter LPF 1. Accordingly, the power supply unit 710 can smoothly operate without being affected by the RF power.

Similarly, the second low pass filter LPF2 electrically connected to the thermocouple 450 may be configured to block signals of a frequency band of RF power generated by the plasma generation unit among signals delivered to the temperature control unit 720. Similarly, when the band of RF power is 60MHz, the second low pass filter LPF2 may be configured to block signals having a band of 60MHz or more. Accordingly, temperature control unit 720 can receive electrical signals without crosstalk caused by RF electrode 320. That is, the temperature control unit 720 may receive the temperature information signal from the thermocouple 450, remove the RF power component from the temperature information signal, and control the power supply unit 710 based on the received temperature information signal. In an alternative embodiment, the first low pass filter LPF1 and the second low pass filter LPF2 may be integrated into a single filter.

In another embodiment, the substrate supporting unit 130 may further include a capacitive element 730 disposed between the second rod 420 and the plasma generating unit. Capacitive element 730 may comprise, for example, a capacitor. Capacitive element 730 may operate as a short circuit in an RF field, but as an open circuit in a DC field. Accordingly, by connecting capacitive element 730 to RF electrode 320, the bias formed on RF electrode 320 (such as the bias formed by the plasma generation unit toward substrate support unit 130) can be raised. Because the bias is a DC field that is a DC voltage, the DC bias developed on RF electrode 320 can be maintained by capacitive element 730 operating as an open circuit.

Fig. 10 to 13 illustrate the substrate supporting unit according to an embodiment of the present disclosure in more detail.

Referring to fig. 10, the upper portion 1 of the substrate support unit and the lower portion 2 of the substrate support unit may be mechanically or integrally connected. The upper and lower fixing units 8 and 9 may be inserted into the upper and lower portions 1 and 2 of the substrate support unit. The upper fixing unit 8 may contact an upper portion of the RF shield 430, and the lower fixing unit 9 may contact a lower portion of the RF shield 430.

As shown in fig. 11 and 12, a plurality of through holes may be formed in the upper fixing unit 8 and the lower fixing unit 9 formed, and the through holes of the upper fixing unit 8 and the through holes of the lower fixing unit 9 are disposed corresponding to each other. The RF rod 420 ', the shield 430 surrounding the RF rod 420 ', and the power rod 410 ' connected to the socket 13 may be disposed to penetrate through the through holes of the upper and lower fixing units 8 and 9. The upper and lower fixing units 8 and 9 may fix and support the positions of the RF rod 420 ', the RF shield 430, and the power rod 410'.

In an alternative embodiment, portions of the lower stationary unit 9 may be formed completely around the perimeter of the RF shield 430. Another portion of the lower stationary unit 9 may be formed partially around the perimeter of the RF shield 430. That is, in the other member, a portion not surrounded by the lower fixing unit 9 may be formed. In an alternative embodiment, the portion that is not surrounded may not be filled with a separate insulating material, and thus an air gap a (not shown) may be formed in the component. In another alternative embodiment, the portion in which the air gap a is formed may be filled with a material having a low dielectric constant.

The position of the lower end of the RF rod 420' may be fixed by the second insulating member 10 and the grounding bracket 11 contacting the second insulating member 10. The grounding bracket 11 may include a first portion extending in the same direction as the extension direction of the second rod as the RF rod 420' and a second portion extending in a direction different from the extension direction of the second rod. In this case, the first portion may be connected to the RF shield 430 while the second portion may be connected to ground G. The ground bracket 11 may have an L shape by a first portion and a second portion. The difference between the inner diameter of the RF shield 430 and the diameter of the second rod 420 may also be equal to the sum of the thickness of the first portion of the ground bracket 11 and the thickness of the second insulating member 10, depending on the assembly structure of the second insulating member 10 and the ground bracket 11.

The socket 12 may be inserted into the lower end of the RF rod 420', the position of which is fixed and supported. The socket 12 may be connected to an RF cable 15 through an RF cable connection port 14, the RF cable connection port 14 being formed on one surface of the RF cable connector 4 to supply an RF current to the RF rod 420' (refer to fig. 13). The lower portion 2 of the substrate support unit may be supported by the lower support body 3 of the substrate support unit 130. The lower support body 3 of the substrate support unit 130 may be inserted into an upper portion of the RF cable connector 4. Accordingly, the positions of the upper and lower portions 1 and 2 and the RF rod 420 ', the RF shield 430, and the power rod 410' of the substrate support unit 130 may be fixed and supported.

The upper and lower fixing units 8 and 9 may contain an insulating material, preferably a ceramic material, to prevent current leakage. The RF shield 430 may comprise a metallic material, preferably an aluminum material, to prevent cross-talk effects of RF currents flowing through the RF rod 420 'to adjacent power supplies connected to the power rod 410'. Further, the RF shield 430 is configured to surround the RF rod 420' inside the heater.

Although not shown in fig. 10, a thermocouple (not shown) may also extend through-holes provided in the upper and lower fixing units 8 and 9 like the RF rod 420 'and the power rod 410'. A thermocouple may be connected between the heater 310 and the temperature control unit 720, may compare an actual heating temperature of the heater 310 with a set temperature, and thus control the power of the power supply.

It will be understood that the shape of each part in the drawings is illustrative for clear understanding of the present disclosure. It should be noted that each portion may be modified into various shapes other than the illustrated shape.

It will be apparent to those skilled in the art that the present disclosure is not limited to the above-described embodiments and drawings, and that various substitutions, modifications and changes may be made therein without departing from the spirit and scope of the present disclosure.

It is to be understood that the embodiments described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment are typically considered applicable to other similar features or aspects in other embodiments.

Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims.