KR100387900B1 - cleanning method of thin layer process device and this layer process device adopting the same - Google Patents

Abstract

A cleaning method applied to a thin film processing apparatus such as a thin film growth apparatus for growing or depositing a thin film or an etching apparatus for etching a thin film, and a thin film processing apparatus using the same are disclosed. The disclosed cleaning method includes: a process object in which a thin film process is performed is ionized, and a cleaning gas made of a predetermined material is ionized into a vacuum chamber in which contaminants generated during thin film process are attached to an inner wall thereof. Introducing the active particles into the vacuum chamber; And evacuating the vacuum chamber to discharge the by-products caused by the reaction between the cleaning gas in the plasma state and the pollutant and the active particles of the plasma. The present invention removes contaminants in a vacuum chamber inevitably generated in a thin film processing apparatus such as a thin film deposition apparatus or an etching apparatus, so that the components in the vacuum chamber do not need to be disassembled and cleaned in a vacuum chamber in a vacuum state. Contaminants can be effectively removed by injecting the cleaning gas into the active particles.

Description

Cleaning method of thin film processing device and thin film processing device applying the same {cleanning method of thin layer process device and this layer process device adopting the same}

The present invention relates to a method for cleaning a thin film processing apparatus and a thin film processing apparatus using the same, which is deposited in a vacuum container or an exhaust pipe such as an insulating thin film, a metal thin film, and an etching apparatus, which are essential materials for a high-integration semiconductor field or a display industry. The present invention relates to a method of cleaning a thin film processing apparatus for effectively removing unwanted substances and a thin film processing apparatus employing the same.

The thin film manufacturing process has a wide range of applications such as microelectronics, optoelectronics, protective coatings, decorative coatings, and optical coatings as well as semiconductor device manufacturing. Such a wide range of thin film materials are commercialized as insulation of semiconductor devices, gate oxide films, protective films, and metal wirings for electrical signal transmission. As such, they have various sensors and electrical, optical, and mechanical properties. It is possible.

In recent years, as DRAMs in semiconductor fields have been highly integrated, the use of thin films having very fine line widths and thicknesses is a natural result to make devices having higher integration in a smaller area.

In general, a thin film manufacturing method includes spin on coating using polymer and sol-gel, physical vapor deposition using sputtering or evaporation, and chemical vapor deposition using chemical reaction. (CVD), a deposition method using an ion beam, and a method of directly depositing liquid vapor are used.

The most used methods in the semiconductor field are spin on coating, physical vapor deposition and chemical vapor deposition. In particular, the technique of depositing thin films by chemical vapor deposition has been increasing in demand with increasing density, and it can overcome the shortcomings of the existing physical vapor deposition, but the technique of controlling chemical reaction requires very complicated and fine control. Doing.

Chemical vapor deposition technology is the most common technique to inject a variety of gases and then induce the reaction of the gases using energy such as heat, light, plasma (gas) in the gases to deposit on the substrate. In the chemical vapor deposition method, the chemical reaction rate is controlled by heat, light, plasma, or the like, which supplies reaction energy, or by the amount and ratio of gas. However, these chemical reactions generally occur very quickly and are difficult to control to deposit with the thermodynamic stability of the atoms. The thin film deposited by the chemical vapor deposition method has a disadvantage in that physical, electrical, chemical properties, etc. are inferior to the thin film by physical vapor deposition, but it is an advantageous method for securing thin film uniformity in minute unevenness.

All thin film deposition apparatuses, including chemical vapor deposition apparatuses, cannot be deposited only on desired substrates, and deposition is required not only on the periphery of the substrate but also on all the exhaust pipes, requiring periodic cleaning. These results indicate that even in a device that etches only a portion of the substrate, an etched material or an additional polymer generated during etching is deposited in a vacuum vessel or an exhaust pipe to generate contaminated particles or to change the electrical properties of the vacuum vessel. Make it not stable. In order to prevent this, periodic cleaning is necessary, which causes a large decrease in the operating efficiency of the thin film deposition apparatus.

As such, the cleaning method for removing contaminants attached to the thin film processing apparatus is generally wet cleaning and fine cleaning using a chemical reaction after separating the internal parts of the thin film processing apparatus and immersing in an aqueous solution causing chemical reaction with the contaminants. A dry cleaning method is used in which particles are sprayed at high speed to be physically separated, or plasma is generated in the object to be cleaned to accelerate and clean the ions at high speed. In addition, the case of washing through a continuous process using a combination of physical cleaning and chemical cleaning described above is more commonly used.

Cleaning using a chemical reaction generates a large amount of contaminants generated after the reaction with the chemical to be cleaned, not only causing environmental pollution but also harmful to the human body, requiring special attention for its use. In particular, since a large amount of chemical reaction solution is used, it is easy to cause environmental pollution, and the cost of processing is high. In addition, there is a disadvantage of significantly reducing productivity by stopping the operation of the equipment for a long time.

The method of physically spraying fine powder at high speed to remove contaminants has a disadvantage in that the surface is very roughly deformed or its shape is deformed after removing the contaminants. In addition, a method of using a plasma, which is a physical cleaning method, generates a plasma by applying a negative voltage to the object to be cleaned, and then receives the electrical acceleration of the positive ions in the plasma to remove contaminants deposited on the surface of the object to be cleaned. How to remove. This method also has the disadvantage that the surface roughness of the object to be cleaned is large or the shape itself is easily deformed, and the apparatus is complicated. In particular, it is difficult to make a stable process condition after cleaning because the fine contaminant particles are difficult to be exhausted sufficiently, and like chemical cleaning, there is a disadvantage that the equipment must be stopped for a long time.

SUMMARY OF THE INVENTION The present invention provides a method for increasing the effective operation efficiency of a device by effectively removing unwanted contaminant thin films in a vacuum container, all components placed in the vacuum container, and an exhaust pipe in a vacuum state in a thin film deposition apparatus or an etching apparatus.

1 is a schematic configuration diagram of a chemical vapor deposition apparatus as a thin film processing apparatus to which the cleaning method of the present invention is applied.

According to the present invention to achieve the above object,

A vacuum chamber in which a thin film or an etching process is performed on the object to be processed;

A gas injection hole for injecting a reaction gas into the vacuum chamber;

An exhaust port for exhausting the gas in the vacuum chamber;

A gas inlet connected to the gas inlet;

And an induction coil for forming an induction magnetic field in the gas introduction portion outside the vacuum chamber, and ionizing a predetermined cleaning gas passing through the gas introduction portion to generate a cleaning plasma including active particles to attach to the chamber. A cleaning plasma generator configured to generate at least a gas plasma for removing the contaminated substances;

Provided is a thin film processing apparatus having a power supply unit for supplying power to the cleaning plasma generation unit.

In addition, according to the present invention to achieve the above object,

An object to be processed in a thin film process is installed, and a cleaning gas made of a predetermined material is activated into a vacuum chamber having contaminants generated during the thin film process on an inner wall thereof to activate the cleaning gas into the vacuum chamber. Introducing an inner wall on the flow path in the vacuum chamber in which the cleaning gas flows in the plasma state is electrically grounded so that ions and electrons contained in the cleaning plasma are induced to the inner wall, and Allowing only particles to react with contaminants in the vacuum chamber;

There is provided a cleaning method of a thin film processing apparatus comprising a step of discharging the by-product by the reaction between the cleaning gas and the pollutant and the active particles of the plasma.

It is preferable to apply NF ₃ as the cleaning gas, and further, at least one selected from the group consisting of Ar, O ₂ , H ₂ , and H ₂ O is preferably included in the cleaning gas.

The vacuum pressure at the time of vacuum exhaust of the chamber is set to 10 Torr or less, preferably in the range of 8 mTorr to 10 Torr, in particular, the cleaning target in the chamber that is cleaned by the cleaning plasma gas It is preferred to heat in the range of 20 to 500 ° C.

The thin film processing apparatus and the method of cleaning the thin film processing apparatus of the present invention as described above, do not generate a plasma directly to the object to be cleaned, but after generating a remote plasma (outside plasma) outside the chamber and guided into the chamber The radicals generated in the plasma cause chemical reactions with the object to be cleaned.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the cleaning method and the thin film processing apparatus to which the present invention is applied.

1 is a schematic configuration diagram of a chemical vapor deposition apparatus to which the cleaning method of the present invention is applied.

Upper and lower heater assemblies 2a, 2b are located in the vacuum chamber 1a enclosed by the wall 1. On the inner surface of the lower heater assemblies 2a and 2b, the wafer 3, which is a thin film process target, is positioned. Here, the wafer 3 is removed when the cleaning method of the present invention is carried out. As shown in Fig. 1, contaminants 6, which are to be cleaned, are attached to the inner wall of the wall 1a of the vacuum chamber 1a and the surfaces of the upper and lower heater assemblies 2a and 2b.

An exhaust port 1b and an exhaust device 1c for exhausting the vacuum chamber 1a in a vacuum state are provided at one lower side of the wall 1. The other side of the wall 1 is provided with an introduction tube 4 for introducing a reaction gas between the upper and lower heater assemblies 2a, 2b. Here, the introduction tube 4 extends between the upper and lower heater assemblies 2a and 2b as shown, and in some cases, may be connected only to the wall 1. Preferably, as shown in FIG. 1, it extends between the upper and lower heater assemblies 2a, 2b, which are the introduction tubes 4, in particular the walls of the flow space through which the plasma flows are electrically It is preferable to be grounded.

On the outside of the vacuum chamber 1a, a cleaning plasma generating chamber 5 connected to the introduction section 4 is provided, and an induction coil 5a is wound around the vacuum chamber 1a.

The induction coil 5a is an element of the cleaning plasma generator, and is connected to the frequency measuring unit 5c through an impedance matching unit 5b, and the frequency measuring unit 5c is connected to the power supply device 5d. It is.

The power supply unit 5d rectifies an AC power supply having a low frequency, for example, 220 volts 60 Hz, generates an AC of 1 MHz to 13.56 MHz, and amplifies and outputs it.

The frequency measuring unit 5c measures the frequency of power from the power supply unit 5d, and the impedance matching unit 5b matches the impedance of the floating coil.

The output from the power supply 5d is measured only once and used to control the gain of the high frequency amplifier provided therein.

The induction coil 5, which is supplied with high frequency power, ionizes a cleaning gas introduced by an induction magnetic field in a strong energy state, and generates a cleaning plasma having electrons and active particles. In this high-density plasma, activated particles, ions and electrons coexist, leading to the vacuum chamber 1 to which the object to be cleaned 6 is attached. The ions and electrons escape through the wall of the introduction tube. During exit or through the induction tube, they react with each other to become neutral gases, and only excited species, or radicals, react chemically with the cleansing material in the vacuum chamber, that is, with contaminants (6). This will cause cleaning of the object to be cleaned.

According to the present invention, the gas injected into the plasma generating chamber 5 basically uses NF ₃ , and at least one selected from the group consisting of a small amount of Ar, O ₂ , H ₂ , and H ₂ O is added. It is desirable to. The main gas, NF _3, and the additive gas are decomposed in a plasma in a continuous reaction as in Scheme 1 below.

NF ₃ + e ^-- > NF ₂ + F ^*

NF ₂ + e ^-- > NF + F ^*

NF + e ^-- > N + F ^*

N + N-> N ₂

Likewise, when H ₂ O is contained, it is continuously decomposed by the following schemes.

^{_{H 2 O + e - ->}} H * + OH

H + F ^* -> HF

F ^* + F ^* -> F ₂

O ^* + O ^* -> O ₂

In addition, when O ₂ is included, a reaction as in Scheme 3 below occurs, and at the same time, a reverse reaction is also actively performed.

O ₂ + e ^_- > O ^* + O ^* + e ^_

Excited species are introduced into the vacuum chamber 1 having a cleansing material at a very high speed in a vacuum state and are deposited by the deposits deposited in the vacuum chamber 1 and the following reaction equations. The reaction is discharged to the outside through the exhaust port 6 as a by-product.

In the case where the object to be cleaned, that is, the contaminant 6 is Si, the following reaction formula 4 is used.

Si + F ^* -> SiF or

SiF + F ^* -> SiF ₂ or

SiF ₂ + F ^* -> SiF ₃

In addition, when the substance to be cleaned, that is, the contaminant 6 is SiO ₂ , follows the following Reaction Scheme 5.

SiO ₂ + HF-> SiF ₂ + 2H ₂ O

In addition, when the substance to be cleaned, that is, the contaminant 6 is Al ₂ O ₃ , follows the following Reaction Scheme 6.

2Al ₂ O ₃ + 4F ^* -> 4AlF + 3O ₂

It can be applied to the cleaning of all materials not described in the above examples, and can be described by similar reaction mechanisms.

Similarly, in the cleaning of the polymer generated in the etching apparatus, a similar reaction can effectively clean the polymer deposited in the vacuum vessel, and in particular, even when the main gas contains the additive gas, it can be cleaned by the similar reaction mechanism.

In the cleaning method of the present invention as described above, the vacuum pressure in the vacuum chamber (1a) at the time of cleaning is maintained in the range of 10 Torr or less, preferably 8 mTorr ~ 10 Torr, and the temperature of the object to be cleaned at 20 Heating in the range of ˜500 ° C. enables more effective cleaning.

The cleaning method of the present invention as described above may be applied to other thin film processing apparatuses other than the chemical vapor deposition apparatus illustrated in FIG. 1. Applicable apparatuses include a thin film growth apparatus and a thin film etching apparatus.

In the present invention, the thin film deposition apparatus or the etching apparatus inevitably removes contaminants deposited around the substrate or the exhaust pipe in the vacuum chamber, or in order to remove the components in the vacuum chamber and soak them in an aqueous solution. Effective removal of NF ₃ gas under vacuum without the need to operate the device efficiently can greatly improve productivity and significantly reduce production costs by reducing waste solution emissions.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only in the appended claims.

Claims (10)

A vacuum chamber in which a thin film process is performed on the object to be processed; A gas injection hole for injecting a reaction gas into the vacuum chamber; An exhaust port for exhausting the gas in the vacuum chamber; A gas inlet connected to the gas inlet; And an induction coil forming an induction magnetic field in the gas introduction portion outside the vacuum chamber, and ionizing a predetermined cleaning gas passing through the gas introduction portion to generate a cleaning plasma including active particles. A cleaning plasma generator for generating at least a gas plasma for removing contaminants adhered therein; And a power supply unit for supplying power to the cleaning plasma generator. The method of claim 1, A thin film processing apparatus, wherein the wall of the flow space in the chamber through which the plasma flows is electrically grounded. The object to be processed in the thin film process is installed, and the cleaning gas made of a predetermined material is ionized into the vacuum chamber having the contaminants generated during the thin film process attached to the inner wall to activate the cleaning gas into the vacuum chamber. Introducing into the particulate state; The inner wall on the flow path in the vacuum chamber in which the cleaning gas flows in the plasma state is electrically grounded to cause ions and electrons contained in the cleaning plasma to be guided to the inner wall, and only the active particles are in the vacuum chamber. Reacting with contaminants; And discharging the by-product by the reaction between the cleaning gas and the pollutant and the active particles of the plasma. delete The method of claim 3, wherein NF ₃ is applied as the cleaning gas. The method of claim 5, And the cleaning gas includes at least one selected from the group consisting of Ar, O ₂ , H ₂ , and H ₂ O. The method according to any one of claims 3, 5, and 6, The vacuum pressure at the time of the vacuum exhaust of the vacuum chamber is set within the range of 8mTorr to 10Torr. delete The method according to any one of claims 3, 5, and 6, And a cleaning material in the chamber where cleaning is performed by the cleaning plasma in a range of 20 to 500 ° C. The method of claim 7, wherein And a cleaning material in the chamber where cleaning is performed by the cleaning plasma in a range of 20 to 500 ° C.