WO2025080012A1 - Substrate processing method - Google Patents

Abstract

The present invention relates to a substrate processing method and, more specifically, to a substrate processing method for growing a thin film on a substrate. The substrate processing method according to an embodiment of the present invention includes: a preparation step of preparing a substrate in a reaction space; a cleaning step of exposing the substrate to first plasma; a thin film forming step of forming a thin film on the substrate; and an etching step of exposing, to second plasma, the substrate on which the thin film is formed.

Description

Substrate processing method

The present invention relates to a substrate processing method, and more specifically, to a substrate processing method for growing a thin film on a substrate.

Semiconductor devices are used in various electronics industries due to their characteristics such as miniaturization, multi-functionality, and low manufacturing cost.

Such semiconductor devices may include memory devices that store data, logic devices that perform computational processing on data, and hybrid devices that can perform various functions simultaneously.

As the electronics industry is highly developed, the demand for high integration of semiconductor devices is becoming increasingly severe. Accordingly, various problems such as a decrease in the process margin of the exposure process that defines fine patterns are occurring, making it increasingly difficult to implement highly integrated semiconductor devices. In addition, the demand for high-speed semiconductor devices is also becoming increasingly severe due to the development of the electronics industry. Various studies are being conducted to meet these demands for high integration and/or high-speed semiconductor devices.

(Prior art literature)

Korean Patent Publication No. 10-2008-0112932

The present invention provides a substrate processing method capable of selectively growing a thin film on a substrate.

A substrate processing method according to an embodiment of the present invention includes a preparation step of providing a substrate in a reaction space; a cleaning step of exposing the substrate to a first plasma; a thin film forming step of forming a thin film on the substrate; and an etching step of exposing the substrate on which the thin film is formed to a second plasma.

The second plasma can be formed of a gas including one or more of a chlorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas.

The above first plasma can be formed by a gas including one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas.

The process cycle including the above cleaning step, thin film formation step, and etching step can be repeated multiple times.

The above first plasma can be formed with a gas containing one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas, and then formed with a chlorine-containing gas.

The substrate includes a first region and a second region, and the thin film forming step forms a thin film on the second region that is thinner than the thin film formed on the first region, and the etching step can remove the thin film formed on the first region and the second region so that the second region is exposed.

The first region may include a region where silicon is exposed onto the substrate, and the second region may include a region where at least one of silicon oxide and silicon nitride is exposed onto the substrate.

The above thin film forming step can form a silicon or silicon germanium thin film on the substrate.

The above etching step may include a step of supplying chlorine gas to the reaction space; a step of supplying argon gas to the reaction space; and a step of forming plasma of the chlorine gas and argon gas.

The above etching step further includes a step of supplying hydrogen gas to the reaction space; and the step of forming plasma can form plasma of the chlorine gas, argon gas, and hydrogen gas.

The first plasma and the second plasma may include inductively coupled plasma.

After the etching step, the method further includes a purge step of forming a third plasma in the reaction space, wherein the third plasma can be formed of a hydrogen-containing gas.

According to an embodiment of the present invention, a high-quality thin film can be formed on a substrate by performing a cleaning step using a first plasma before forming a thin film on a substrate, and performing an etching step using a second plasma after forming the thin film on the substrate.

In addition, a natural oxide film formed on a substrate or impurities remaining on the substrate before forming a thin film can be effectively removed using plasma formed with a gas including one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas.

In addition, by forming a thin film using plasma formed by a gas including one or more of a chlorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas, and then removing the thin film deposited in an unwanted area, a thin film can be selectively grown on a substrate with high efficiency.

FIG. 1 is a drawing schematically showing a substrate processing device according to an embodiment of the present invention.

FIG. 2 is a drawing schematically showing a substrate processing method according to an embodiment of the present invention.

FIG. 3 is a drawing showing a substrate prepared according to an embodiment of the present invention.

FIG. 4 is a drawing showing a thin film formed on a substrate according to an embodiment of the present invention.

FIG. 5 is a drawing showing a thin film etched according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and the embodiments of the present invention are provided only to make the disclosure of the present invention complete and to fully inform a person having ordinary skill in the art of the scope of the invention. In order to describe the invention in detail, the drawings may be exaggerated, and the same reference numerals in the drawings represent the same elements.

FIG. 1 is a drawing schematically showing a substrate processing device according to an embodiment of the present invention.

Referring to FIG. 1, a substrate processing device according to an embodiment of the present invention is a device for selectively growing a thin film, for example, a silicon germanium thin film, and may include a chamber (100) that provides a reaction space, a support (200) installed inside the chamber (100) to support a substrate (S), an injection unit (300) installed in the chamber (100) to inject gas into the inside of the chamber (100), a plasma generation unit (400) located outside the chamber (100) to generate plasma inside the chamber (100), and a control unit (700) that controls the operation of the plasma generation unit (400).

In addition, the substrate processing device may include a heating unit (500) installed so that at least a portion thereof faces the support (200), a driving unit (600) that raises and lowers or rotates the support (200), and an exhaust unit (not shown) that exhausts gas and impurities inside the chamber (100).

The substrate (S) processed in such a substrate processing device may be, for example, a wafer. More specifically, the substrate (S) may be a silicon wafer, and may have a state in which a dielectric layer (K) is formed on some area of the silicon wafer. For example, the substrate (S) may have a state in which a dielectric layer (K) including at least one of silicon oxide (SiO) and silicon nitride (SiN) is discontinuously formed on an upper surface of the silicon wafer. Accordingly, a part of the upper surface of the substrate may be covered by the dielectric layer (K), and the rest may be exposed.

According to this substrate (S), selective growth is achieved in which a thin film (T) is grown in an area of the upper surface where a dielectric layer (K) is not formed. The process of selectively growing a thin film (T) on the substrate (S) will be described in detail later.

The chamber (100) may include a chamber body (110), an upper body (120) installed on the upper side of the chamber body (110), and a lower body (130) installed on the lower side of the chamber body (110). The chamber body (110) may have a cylindrical shape with the upper and lower sides open, and the upper body (120) may be installed to cover the upper opening of the chamber body (110), and the lower body (130) may be installed to cover the lower opening of the chamber body (110). In addition, the upper body (120) may have a dome shape with a slope whose height increases toward the center in the width direction. Each of the chamber (100), that is, the chamber body (110), the upper body (120), and the lower body (130) may be made of a transparent material that allows light to pass through, and may be made of, for example, quartz.

The support (200) is a means for supporting a substrate (S) on one side, for example, an upper side, and can be installed inside the chamber (100). This support (200) can be provided to have a larger area than the substrate (S), and can be provided in a shape corresponding to the substrate (S), for example, a square or circular shape. Of course, the support (200) can be provided to have the same area as the substrate (S) or a smaller area than the substrate (S).

The driving unit (600) may be a means for operating the support (200) in at least one of raising/lowering and rotating. The driving unit (600) may include a driving source (610) that is installed on the lower outer side of the chamber (100) and provides power for at least one of raising/lowering and rotating, and a driving shaft (620) that has one end connected to the support (200) and the other end connected to the driving source (610). According to the driving unit (600), the driving shaft (620) and the support (200) connected thereto may operate in at least one of raising/lowering and rotating for the operation of the driving source (610).

The heating unit (500) is a means for heating the interior of the chamber (100) and the support (200), and may be installed on the exterior of the chamber (100). More specifically, the heating unit (500) may be installed on the lower side of the exterior of the chamber (100) so that at least a portion thereof may face the support (200). This heating unit (500) may be a means including a plurality of lamps, and the plurality of lamps may be installed in a row in the width direction of the support (200). In addition, the plurality of lamps may include lamps such as halogen lamps that emit radiant heat.

The injection unit (300) injects gas toward the substrate (S) mounted on the support (200) inside the chamber (100). The injection unit (300) may be installed in the chamber (100) so that one end from which the gas is injected may be located inside the chamber (100). At this time, the injection unit (300) may be installed on a side of the chamber (100), for example, on the chamber body (110), as illustrated in FIG. 1, and may be in the form of a pipe through which gas may pass. In addition, the injection unit (300) may be provided to be inclined upward so that its height increases toward the one end from which the gas is injected, as illustrated in FIG. 1.

Of course, the installation location, arrangement, shape, etc. of the injection unit (300) are not limited to the above-described example and may be modified in various ways. That is, the injection unit (300) may be installed in any location as long as the end from which the gas is injected can face the support (200), and may be installed, for example, in the upper body (120) of the chamber (100). In addition, the injection unit (300) may be provided in a horizontal state without being inclined upward, and may be modified in various forms capable of injecting gas toward the substrate (S) without being limited to a pipe shape.

The gas injected from the injection unit (300) may be a cleaning gas for removing a natural oxide film formed on the substrate (S) or impurities remaining on the substrate (S). In addition, the gas injected from the injection unit (300) may be a process gas for growing and forming a thin film (T) on the substrate (S). In addition, the gas injected from the injection unit (300) may be an etching gas for etching the thin film (T) formed on the substrate (S). The injection unit (300) may selectively inject such cleaning gas, process gas, and etching gas.

The cleaning gas may include a gas that is injected to remove a natural oxide film formed on the substrate (S) or impurities remaining on the substrate (S). For example, when the substrate (S) includes a silicon wafer and a natural oxide film formed on the substrate (S) or impurities including carbon (C) or oxygen (O) components remaining on the substrate (S) are removed, the cleaning gas may be a gas that includes one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas. At this time, the fluorine (F)-containing gas may be sulfur hexafluoride gas (SF ₆ ), the hydrogen (H)-containing gas may be hydrogen gas (H ₂ ), the helium (He)-containing gas may be helium gas (He), and the argon (Ar)-containing gas may be argon gas (Ar).

The process gas may include a gas injected to grow a thin film (T) on a substrate (S). Such a process gas may vary depending on the type of the substrate (S) or the type of the thin film to be grown. For example, if the substrate (S) includes a silicon wafer and a thin film (T) made of silicon (Si) is to be grown on the substrate (S), the process gas may contain silicon (Si). In addition, if a thin film (T) made of germanium (Ge) is to be grown on the substrate (S), the process gas may contain germanium (Ge). Meanwhile, if a thin film (T) made of silicon germanium (SiGe) is to be grown on the substrate (S), the process gas may include a raw material gas containing silicon (Si) and a reaction gas containing germanium (Ge). At this time, the raw material gas containing silicon (Si) may include silane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), tetrasilane (Si ₄ H ₁₀ ), dichlorosilane (SiH ₂ Cl ₂ ), tetrachlorosilane (SiCl ₄ ), hexachlorodisilane (Si ₂ Cl ₆ ), trichlorosilane (SiHCl ₃ ), methylsilane ((CH ₃ )SiH ₃ ), dimethylsilane ((CH ₃ ) ₂ SiH ₂ ), ethylsilane ((CH ₃ CH ₂ )SiH ₃ ), methyldisilane ((CH ₃ )Si ₂ H ₅ ), dimethyldisilane ((CH ₃ ) ₂ Si ₂ H ₄ ), and hexamethyldisilane ((CH ₃ ) ₆ Si ₂ ). Meanwhile, the reaction gas containing germanium (Ge) may include digermane (Ge ₂ H ₆ ), trigermane (Ge ₃ H ₈ ), tetragermane (Ge ₄ H ₁₀ ), germanium tetrachloride (GeCl ₄ ), trichlorogermane (GeHCl ₃ ), methylgermane ((CH ₃ )GeH ₃ ), dimethylgermane ((CH ₃ ) ₂ GeH ₂ ), ethylgermane ((CH ₃ CH ₂ )GeH ₃ ), methyldigermane ((CH ₃ )Ge ₂ H ₅ ), dimethyldigermane ((CH ₃ ) ₂ Ge ₂ H ₄ ), and hexamethyldigermane ((CH ₃ ) ₆ Ge ₂ ).

The etching gas may include a gas injected to etch a thin film (T) formed on a substrate (S). For example, when the substrate (S) includes a silicon wafer and a silicon (Si) thin film, a germanium (Ge) thin film, or a silicon germanium (SiGe) thin film formed on the substrate (S) is to be etched, the etching gas may be a gas including one or more of a chlorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas. At this time, the chlorine (Cl)-containing gas may be chlorine gas (Cl ₂ ), the hydrogen ((H)-containing gas may be hydrogen gas (H ₂ ), the helium (He)-containing gas may be helium gas (He), and the argon (Ar)-containing gas may be argon gas (Ar).

The plasma generating unit (400) is provided at the upper part of the chamber (100), that is, at the upper part of the upper body (120), and ionizes the gas supplied into the interior of the chamber (100) to generate plasma. This plasma generating unit (400) may be a means for generating inductively coupled plasma (ICP). That is, the plasma generating unit (400) may include an antenna having a coil (410) for inducing an electric field within the chamber (100), as shown in FIG. 1, and a power supply unit (420) connected to the coil (410) and applying RF power.

The coil (410) may be installed on the upper part of the upper body (120). At this time, the coil (410) may be provided in a spiral shape wound with multiple turns, or may be configured to include a plurality of circular coils arranged in a concentric shape and connected to each other. Of course, the coil (410) is not limited to a spiral coil or a concentric circular coil, and various coils having different shapes may be applied.

Additionally, the coil (410) may be formed as a double-layer structure including a lower coil installed adjacent to the upper portion of the upper body (120) and an upper coil installed spaced apart from the upper portion of the lower coil.

These coils (410) can be manufactured from a conductive material such as copper, and can be manufactured in a hollow tube shape. If the coil (410) is manufactured in a tube shape, cooling water or refrigerant can flow, so that the temperature rise of the coil can be suppressed.

In addition, one end of the coil (410) may be connected to a power supply (420), and the other end may be connected to a ground terminal. Accordingly, when RF power is applied to the coil through the power supply (420), the gas sprayed into the chamber (100) is ionized or discharged to generate plasma inside the chamber (100).

The control unit (700) can control the operation of the injection unit (300) and the plasma generation unit (400). More specifically, the control unit (700) can supply a gas required for at least one of the cleaning process, the thin film formation process, and the etching process into the chamber (100) and operate the plasma generation unit (400) so that plasma can be generated inside the chamber (100). At this time, the control unit (700) can adjust the intensity of the RF power applied in some of the cleaning process, the thin film formation process, and the etching process to be different from the intensity of the RF power applied in other processes.

Hereinafter, a substrate processing method according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 5. The substrate processing method according to an embodiment of the present invention is a method of processing a substrate using the substrate processing apparatus described above. In the description of the substrate processing method, any description that overlaps with the description of the substrate processing apparatus described above will be omitted.

FIG. 2 is a drawing schematically showing a substrate processing method according to an embodiment of the present invention. FIG. 3 is a drawing showing a substrate prepared according to an embodiment of the present invention, FIG. 4 is a drawing showing a thin film formed on a substrate according to an embodiment of the present invention, and FIG. 5 is a drawing showing a thin film etched according to an embodiment of the present invention.

Referring to FIGS. 2 to 5, a substrate processing method according to an embodiment of the present invention includes a preparation step (S100) of providing a substrate (S) in a reaction space, a cleaning step (S200) of exposing the substrate (S) to a first plasma, a thin film formation step (S300) of forming a thin film (T) on the substrate (S), and an etching step of exposing the substrate (S) on which the thin film (T) is formed to a second plasma. At this time, the first plasma may be formed with a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas, and the second plasma may be formed with a gas including one or more of a chlorine (Cl)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas.

In the preparation step (S100), first, a substrate (S) is introduced into the reaction space of the chamber (10). The substrate (S) introduced into the reaction space may be placed on a support (200). Here, the substrate (S) may include various semiconductor substrates. For example, the substrate (S) may include a silicon wafer, and such a silicon wafer may be locally covered with an oxide film or a nitride film. That is, the substrate (S) may include a first region (A) and a second region (B) as illustrated in FIG. 3. Here, the first region (A) may be a region where the substrate (S) is exposed, and the second region (B) may include a region where the covered oxide film or nitride film covering the substrate (S) is exposed. For example, the first region (A) may be a region where a silicon wafer is exposed on the surface because a dielectric layer (K) including at least one of silicon oxide (SiO) and silicon nitride (SiN) is not formed, and the second region (B) may be a region where a dielectric material (K) including at least one of silicon oxide (SiO) and silicon nitride (SiN) is formed on the silicon wafer and the dielectric layer (K) is exposed on the surface. Such a substrate (S) is supported on a support (200), and the support (200) may be provided with, for example, an electrostatic chuck or the like to adsorb and hold the substrate (S) by electrostatic force, or may support the substrate (S) by vacuum adsorption or mechanical force.

The cleaning step (S200) can be performed by exposing the substrate (S) to a first plasma formed of a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas.

As described below, in the thin film formation step (S300), a thin film is formed on the substrate (S). In the thin film formation step (S300), a relatively thick thin film is formed in the first region (A) where the silicon wafer is exposed, and a relatively thin thin film is formed in the second region (B) where at least one of silicon oxide (SiO) and silicon nitride (SiN) is exposed. However, before the thin film formation step (S300), the substrate (S) may be oxidized, and a natural oxide film may be formed in the first region (A), and such a natural oxide film acts as a factor that hinders the growth of the thin film. Therefore, it is necessary to remove such a natural oxide film before performing the thin film formation step (S300).

In addition, as described below, in the etching step (S400), the substrate (S) on which the thin film is formed is exposed to the second plasma and etched, and this process cycle can be repeated multiple times until a thin film of a desired thickness is formed. However, in the etching step (S400), various by-products are generated, and when such by-products exist in the first region (A), the growth of the thin film is hindered by the by-products. Therefore, such by-products also need to be removed.

Therefore, in the cleaning step (S200), the substrate (S) is cleaned by exposing it to a first plasma formed with a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas before the thin film forming step (S300). To this end, the cleaning step (S200) may include a step of supplying a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas from an injection unit (300), and a step of ionizing the gas including one or more of the supplied fluorine (F)-containing gas, hydrogen (H)-containing gas, helium (He)-containing gas, and argon (Ar)-containing gas by a plasma generating unit (400) to form a first plasma. The substrate (S) is exposed to the first plasma formed in this manner so that a natural oxide film, impurities, etc. can be removed.

At this time, the cleaning step (S200) may include a step of supplying sulfur hexafluoride gas (SF ₆ ) to the reaction space of the chamber (100), a step of supplying argon gas (Ar) to the reaction space, and a step of forming plasma of the sulfur hexafluoride gas (SF ₆ ) and argon gas (Ar). Here, the step of supplying sulfur hexafluoride gas (SF ₆ ) and the step of supplying argon gas (Ar) do not have a time-series relationship, and it goes without saying that sulfur hexafluoride gas (SF ₆ ) may be supplied and argon gas (Ar) supplied, argon gas (Ar) may be supplied and sulfur hexafluoride gas (SF ₆ ) supplied, or sulfur hexafluoride gas (SF ₆ ) and argon gas (Ar) may be supplied simultaneously. In this way, when forming plasma by supplying argon gas (Ar) together with sulfur hexafluoride gas (SF ₆ ), the sulfur hexafluoride gas (SF ₆ ) can be more effectively diffused by the argon gas (Ar), thereby promoting the cleaning reaction.

In addition, the cleaning step (S200) may further include a step of supplying hydrogen gas (H ₂ ) in addition to sulfur hexafluoride gas (SF ₆ ) and argon gas (Ar). In this case, the substrate (S) may be exposed to plasma of sulfur hexafluoride gas (SF ₆ ), argon gas (Ar), and hydrogen gas (H ₂ ), and the reactivity of sulfur hexafluoride gas (SF ₆ ) may be enhanced by the argon gas (Ar) and hydrogen gas (H ₂ ), thereby further promoting the cleaning reaction.

In addition, the first plasma formed in the cleaning step (S200) may be formed with a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas, and then formed with a chlorine (Cl)-containing gas. For example, in the cleaning step (S200), at least one of sulfur hexafluoride gas (SF ₆ ), hydrogen gas (H ₂ ), helium gas (He), and argon gas (Ar) may be supplied to the reaction space of the chamber (100) to form plasma, and then chlorine gas (Cl ₂ ) may be supplied to form plasma. In this way, by forming the first plasma formed in the cleaning step (S200) with a gas containing one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas, and then forming it with a chlorine (Cl)-containing gas, the natural oxide film formed on the substrate (S) or impurities remaining on the substrate can be more effectively removed.

In the thin film formation step (S300), as illustrated in FIG. 4, a thin film (T) thinner than the thin film (T) formed on the first region of the substrate (S) can be formed on the second region of the substrate (S). As described above, the substrate (S) can include a first region (A) and a second region (B), and the first region (A) can be a region where the substrate (S), for example, a silicon wafer, is exposed onto the substrate (S), and when the process cycle is performed multiple times, the first region (A) can be a region where a thin film including silicon (Si) or silicon germanium (SiGe) is formed. Meanwhile, the second region (B) can include a region where at least one of silicon oxide (SiO) and silicon nitride (SiN) is exposed onto the substrate (S). At this time, the thin film (T) including silicon (Si) or silicon germanium (SiGe) may be deposited relatively thickly in the first region (A) where the substrate (S) or the thin film (T) including silicon (Si) or silicon germanium (SiGe) is already formed, compared to the second region (B), and may be deposited relatively thinly in the second region (B) where a dielectric layer (K) such as silicon oxide (SiO) and silicon nitride (SiN) is formed, compared to the first region (A). That is, the thickness (D1) of the thin film (T) formed in the first region (A) may be thicker than the thickness (D2) of the thin film (T) formed in the second region (B).

In this way, the thin film formation step (S300) can form a thin film containing silicon (Si) by supplying a silicon (Si) containing gas through the injection unit (300).

Meanwhile, the thin film formation step (S300) may form a thin film on the substrate (S) by an atomic layer deposition process. That is, the step of forming the thin film (T) may form a thin film by an atomic layer deposition (ALD) process that sequentially performs the steps of supplying a raw material gas through an injection unit (300), supplying a purge gas, supplying a reaction gas, and supplying a purge gas. In such an atomic layer deposition process, plasma may not be formed in the reaction space.

Here, the thin film (T) formed on the substrate (S) by the atomic layer deposition process may include silicon germanium (SiGe). To this end, in the step of supplying the raw material gas, a silicon (Si)-containing gas may be supplied as the raw material gas. The silicon (Si) containing gas may include at least one of, for example, silane (SiH ₄ ), disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), tetrasilane (Si ₄ H ₁₀ ), dichlorosilane (SiH ₂ Cl ₂ ), tetrachlorosilane (SiCl ₄ ), hexachlorodisilane (Si ₂ Cl ₆ ), trichlorosilane (SiHCl ₃ ), methylsilane ((CH ₃ )SiH ₃ ), dimethylsilane ((CH ₃ ) ₂ SiH ₂ ), ethylsilane ((CH ₃ CH ₂ )SiH ₃ ), methyldisilane ((CH ₃ )Si ₂ H ₅ ), dimethyldisilane ((CH ₃ ) ₂ Si ₂ H ₄ ), and hexamethyldisilane ((CH ₃ ) ₆ Si ₂ ). Additionally, in the step of supplying a reaction gas, a germanium (Ge)-containing gas can be supplied as a reaction gas. The germanium (Ge) containing gas may include at least one of, for example, digermane (Ge ₂ H ₆ ), trigermane (Ge ₃ H ₈ ), tetragermane (Ge ₄ H ₁₀ ), germanium tetrachloride (GeCl ₄ ), trichlorogermane (GeHCl ₃ ), methylgermane ((CH ₃ )GeH ₃ ), dimethylgermane ((CH ₃ ) ₂ GeH ₂ ), ethylgermane ((CH ₃ CH ₂ )GeH ₃ ), methyldigermane ((CH ₃ )Ge ₂ H ₅ ), dimethyldigermane ((CH ₃ ) ₂ Ge ₂ H ₄ ), and hexamethyldigermane ((CH ₃ ) ₆ Ge ₂ ).

In the step of forming the thin film (T), as illustrated in FIG. 4, a thin film (T) that is thinner than the thin film (T) formed on the first region of the substrate (S) can be formed on the second region of the substrate (S). That is, the substrate (S) can include a first region (A) and a second region (B), and the first region (A) can be a region where a silicon wafer is exposed on the substrate (S), and the second region can include a region where at least one of silicon oxide (SiO) and silicon nitride (SiN) is exposed on the substrate (S). At this time, the thin film (T) including silicon (Si) or silicon germanium (SiGe) can be deposited relatively thickly in the first region (A) where the silicon wafer is exposed compared to the second region (B), and can be deposited relatively thinly in the second region (B) where a dielectric layer (K) such as silicon oxide (SiO) and silicon nitride (SiN) is formed compared to the first region (A). That is, the thickness (D1) of the thin film (T) formed in the first region (A) may be thicker than the thickness (D2) of the thin film (T) formed in the second region (B).

The etching step (S400) is performed by exposing the substrate (S) to a second plasma formed by a gas including one or more of a chlorine (Cl)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas. To this end, the etching step (S400) may include a step of supplying a gas including one or more of a chlorine (Cl)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas from an injection unit (300), and a step of ionizing the supplied gas including one or more of the chlorine (Cl)-containing gas, the hydrogen (H)-containing gas, the helium (He)-containing gas, and the argon (Ar)-containing gas by a plasma generation unit (400) to form a second plasma. The substrate (S) is exposed to the second plasma formed in this manner, so that a thin film (T) having a predetermined thickness can be etched.

At this time, the etching step (S400) may include a step of supplying chlorine gas (Cl ₂ ) to the reaction space of the chamber (100), a step of supplying argon gas (Ar) to the reaction space, and a step of forming plasma of the chlorine gas (Cl ₂ ) and argon gas (Ar). Here, the step of supplying chlorine gas (Cl ₂ ) and the step of supplying argon gas (Ar) do not have a time-series relationship, and it goes without saying that chlorine gas (Cl ₂ ) may be supplied and argon gas (Ar) supplied, argon gas (Ar) may be supplied and chlorine gas (Cl ₂ ) supplied, or chlorine gas (Cl ₂ ) and argon gas (Ar) may be supplied at the same time. In this way, when argon gas (Ar) is supplied together with chlorine gas (Cl ₂ ) to form plasma, chlorine gas (Cl ₂ ) may be more effectively diffused by the argon gas (Ar), thereby promoting the etching reaction.

In addition, the etching step (S400) may further include a step of supplying hydrogen gas (H ₂ ) in addition to chlorine gas (Cl ₂ ) and argon gas (Ar). In this case, the substrate (S) may be exposed to plasma of chlorine gas (Cl ₂ ), argon gas (Ar), and hydrogen gas (H ₂ ), and the reactivity of chlorine gas (Cl ₂ ) may be enhanced by the argon gas (Ar) and hydrogen gas (H ₂ ), thereby further promoting the etching reaction. The etching step (S400) may remove a thin film formed on the first region (A) and the second region (B) so that the second region (B) of the substrate (S) is exposed, as illustrated in FIG. 5.

In this way, the cleaning step (S200), the thin film formation step (S300), and the etching step (S400) can form one process cycle, and this process cycle can be repeatedly performed multiple times. That is, a cleaning step (S200) of exposing a substrate (S) to a first plasma formed of a gas including one or more of a fluorine (F)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas, a thin film forming step (S300) of forming a thin film (T) including silicon (Si) or silicon germanium (SiGe) on the substrate (S), and an etching step (S400) of exposing the substrate (S) on which the thin film (T) is formed to a second plasma formed of a gas including one or more of a chlorine (Cl)-containing gas, a hydrogen (H)-containing gas, a helium (He)-containing gas, and an argon (Ar)-containing gas constitute one process cycle, and the process cycle can be repeatedly performed until a silicon germanium (SiGe) thin film having a desired thickness is grown on the first region (A) of the substrate (S).

In this way, according to an embodiment of the present invention, a high-quality thin film can be formed on a substrate by performing a cleaning step using a first plasma before forming a thin film on the substrate, and performing an etching step using a second plasma after forming the thin film on the substrate.

In addition, a natural oxide film formed on a substrate or impurities remaining on the substrate before forming a thin film can be effectively removed using plasma formed with a gas including one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas.

In addition, by forming a thin film using plasma formed by a gas including one or more of a chlorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas, and then removing the thin film deposited in an unwanted area, a thin film can be selectively grown on a substrate with high efficiency.

Although the preferred embodiments of the present invention have been described and illustrated using specific terms above, such terms are only for the purpose of clearly describing the present invention, and it is obvious that the embodiments of the present invention and the described terms may be variously changed and modified without departing from the technical spirit and scope of the following claims. Such modified embodiments should not be understood individually from the spirit and scope of the present invention, but should be considered to fall within the claims of the present invention.

Claims (12)

A preparatory step for preparing a substrate in a reaction space; A cleaning step of exposing the substrate to a first plasma; A thin film forming step of forming a thin film on the above substrate; and A substrate processing method, comprising an etching step of exposing a substrate on which the above thin film is formed to a second plasma. In claim 1, A substrate processing method in which the second plasma is formed by a gas containing one or more of a chlorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas. In claim 1, A substrate processing method in which the first plasma is formed by a gas containing one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas. In claim 1, A substrate processing method in which a process cycle including the above cleaning step, thin film forming step, and etching step is repeated multiple times. In claim 3, A substrate processing method in which the first plasma is formed with a gas containing one or more of a fluorine-containing gas, a hydrogen-containing gas, a helium-containing gas, and an argon-containing gas, and then formed with a chlorine-containing gas. In claim 1, The above substrate includes a first region and a second region, The above thin film forming step is, A thin film thinner than the thin film formed on the first region is formed on the second region, The above etching step is, A substrate processing method for removing a thin film formed on the first region and the second region so as to expose the second region. In claim 6, The first region includes a region where silicon is exposed on the substrate, A method for processing a substrate, wherein the second region includes a region on the substrate where at least one of silicon oxide and silicon nitride is exposed. In claim 1, The above thin film forming step is, A substrate processing method for forming a silicon or silicon germanium thin film on the above substrate. In claim 1, The above etching step is, A step of supplying chlorine gas to the above reaction space; A step of supplying argon gas to the above reaction space; and A method for treating a substrate, comprising: forming a plasma of the above chlorine gas and argon gas. In claim 9, The above etching step is, Further comprising a step of supplying hydrogen gas to the above reaction space; The step of forming the above plasma is: A method for treating a substrate by forming a plasma of the above chlorine gas, argon gas and hydrogen gas. In claim 1, A substrate processing method wherein the first plasma and the second plasma include inductively coupled plasma. In claim 1, After the etching step, a purge step of forming a third plasma in the reaction space is further included; A substrate processing method in which the third plasma is formed using a hydrogen-containing gas.

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