An etching processing method, a processing method and a semiconductor manufacturing system

Abstract

A new cyclic etching method, wet-like atomic layer etching (ALE), or wet-like (plasma) ALE, or nanomist (plasma) ALE for damage-free and selective isotropic etching using mist / vapor / plasma at low temperature, that can minimize the damage from sputter effect in plasma ALE, high temperature treatment in thermal ALE during volatilization, and nanostructure damage in wet ALE, has been developed. The modification layer after the reaction with mist or plasma can be removed by dissolving it in a highly volatile mist flow. The phase with intermediate properties between mist liquid phase and vapor phase, named mist-vapor phase or nanomist phase that can maintain the wet properties of liquid phase at the minimal mist size is proposed here for nanodevices applications. By using the Leidenfrost effect, the sample surface can be modified and / or etched by the floating nanomist-assisted vapor.

Description

AN ETCHING PROCESSING METHOD, A PROCESSING METHOD AND A SEMICONDUCTOR MANUFACTURING SYSTEM

[0001] The present invention relates to a semiconductor manufacturing apparatus and method for semiconductor device with a new etching method, named wet-like atomic layer etching (ALE), or wet-like (plasma) ALE, or nanomist (plasma) ALE for damage-free and selective isotropic etching using mist / vapor / plasma at relatively low temperature, that can minimize the damage from sputter effect in plasma ALE, high temperature treatment in thermal ALE during volatilization, and nanostructure damage in wet ALE. The modification layer after the reaction with mist / vapor / plasma can be removed by dissolving it in a highly volatile nanomist flow.

[0002] In the fabrication of next-generation field effect transistor (FET) of logic semiconductor devices, the device size has been downscaled to several nanometers. Hence, selective etching of materials such as metals (W, Cu, Mo, Ru), metal carbides (TiAlC, TiC, AlC), metal nitrides (TiN, TiAlN, AlN), and alloys (TiAl, SiGe) without damage is a challenge and requires a high-performance etching technology. In logic devices, it is required for controlling isotropic etching and selective removal of multiple metal gate materials made of metal or metal containing compounds.

[0003] In traditional dry etching, halogen plasma etchants for metal and metal compounds have been used. However, regarding the selective etching of metal compounds such as TiAlC over TiN, TiAl, TiO2, fluorine-based plasma forms a non-volatile product AlF3(boiling point (b.p.) more than 1290 °C). Chlorine-based plasma form the AlCl3(b.p. ~ 183 °C), but, with the similar volatile product such as TiCl4(b.p. ~ 136 °C), causing poor selective etching. In addition to halogen gas etchants, using non-halogen etchants from precursors with various forms such as gas, liquid, and solid powder can open a wide-range selection of environment-friendly etchants for highly selective formation of volatile products.

[0004] For atomic layer etching (ALE) processes, surface modification is used to reduce surface energy of sample surface in the first step, and the modified layer with lower surface energy is removed in the next step. Two common ALE technologies are applied now is plasma atomic layer etching and thermal atomic layer etching. The drawbacks of these two technologies are dealing with sputter effect in plasma ALE and high temperature in thermal ALE during volatilization step. Recently, another wet ALE has been applied at room temperature as described in NPL 1. In this wet ALE, a self-limiting passivation layer is formed by the reaction with a liquid for surface modification, and the passivation layer is removed by dissolving it in another liquid. This wet ALE can solve the problem of the thermal ALE when the process could be done at low temperature. However, in the wet etching process, the reproductivity of wet etching is poor due to nanopattern collapsing during the drying process. To overcome the problem of both wet etching and dry etching, we have proposed the wet-dry etching or wet-like plasma etching that combines the advantages of wet etching (high isotropy and selectivity) and dry etching (high controllability). By using a floating wire-assisted vapor plasma at medium pressure, a wet-like plasma containing high-density reactive radicals can be remotely generated, this significantly increases the chemical reaction rate to the sample surface. Therefore, the wet-like plasma etching can be applied for highly selective and isotropic etching of metal and metal compounds in the next generation of atomic layer etching.

[0005] C. Netzband et al., “Wet Atomic Layer Etching of Copper Structures for Highly Scaled Copper Hybrid Bonding and Fully Aligned Vias”, 2022 IEEE 72nd Electronic Components and Technology Conference, pages 707-711Yaguchi et al, “Molecular Dynamics Study of the Vapor-Liquid Equilibrium State of an Argon Nanodroplet and Its Vapor”, J. Fluid Science and Technology 2010, pages 180-191

[0006] A next generation fin-shaped and nano-sheets field effect transistor is strongly required a stack of metal thin layers, and hence, isotropic and damage-free selective etching are required. Due to the limitations of current atomic layer etching such as sputter effect from plasma ALE, high temperature from thermal ALE, and nanostructure damage from wet ALE, development of a new ALE method with low-damage to the sample surface is required.

[0007] The present inventors have been developing a new dry etching method, named wet-like atomic layer etching (ALE), or wet-like (plasma) ALE, or nanomist (plasma) ALE for damage-free and selective isotropic etching using mist / vapor / plasma. The process consists of two steps, in which, step 1 is formation of self-limiting passivation layer by mist / vapor / plasma, and step 2 is removal of the passivation layer by dissolving of the passivation layer in a highly volatile nanomist flow at low temperature. In addition, the intermediate phase between mist and vapor, named mist-vapor (nanomist) phase that can maintain the wet properties of liquid phase at the minimal mist size is proposed here for nanodevices applications.

[0008] There are a variety of etchants with various forms such as gas, liquid, and solid powders. The gas etchant can be directly used for dry etching. The liquid etchant, vice versa, can be directly used for wet etching and cannot be directly used for dry etching. In order to use liquid etchant in dry etching, vapor form is often applied. However, multi-component liquid etchants face some challenges for applications in dry etching because it is difficult to simultaneously vaporize its containing components with the original concentration ratio.

[0009] Generally, in order to obtain the mist / vapor from liquid etchant, there are methods such as heating the liquid, using lower pressure in the chamber, or ultrasonic vaporization. Among these methods, for the multi-liquid mixtures with different boiling points and vapor pressures for each single liquid and being decomposed even at low temperature, ultrasonic vaporization is a suitable method to obtain the mist / vapor at low temperature. However, this method has a drawback during the generation of ultrasonic vibration because the ultrasonic vibration is generated on a device called as a mist maker or as an atomizer which contains easily corrosive materials.

[0010] In order to avoid the reaction of corrosive etchant liquids (ex. H2O2, acid, alkaline) with ultrasonic transducer that can produce contamination to the mist, a non-contact atomizer has been developed here to transfer the ultrasonic wave from ultrasonic transducer to liquid canister with special design via water medium. Controlling chemical ratio in each mist droplet and mist size obtained from liquid mixtures is important to obtain the uniform etching.

[0011] In order to maintain the wet properties of mist (liquid phase) and to ensure its deep penetrability into the complex parts inside nanodevices with small dimensions, an intermediate phase between mist and vapor, named mist-vapor phase or nanomist phase is proposed here. The mist-vapor phase or nanomist phase can maintain the wet properties of liquid phase at the minimal mist size. There are several ways to reduce the mist size, such as using high ultrasonic frequency (mega-sonic frequency), adding carrier gas and dilution gas, lowering working pressure than atmospheric pressure by using a vacuum chamber, heating the sample surface, or heating the chamber wall to gasify the mist. By using a vacuum chamber, the working pressure can be controlled less than atmospheric pressure. At the reduced working pressure, the mist size can be reduced to nano-size, and simultaneously, the surface tension of mist is also reduced, that can be easy to enter to the nanopatterns of nanodevices. In order to maintain the properties of mist, medium pressure is preferred.

[0012] Here the technology cyclic etching is applied. As for atomic layer etching, first, surface modification is controlled by treating surface with nanomist / vapor or plasma-activated nanomist / vapor. A cyclic etching can be treated self-limiting manner of using mist / vapor or plasma-activated mist / vapor to modify the sample surface by forming the liquid-like layer on the sample surface and removing this liquid-like layer by high-volatile mist flow at low temperature.

[0013] Plasma is a source of ions, radicals, and so on. At medium pressure (0.2 kPa-50 kPa), the plasma behaves like a fluid with mainly radicals generated to reach the sample surface for isotropic etching. Another new ALE method here is using plasma to modify the sample surface and removing the modified layer by dissolving the modified layer in a highly volatile nanomist flow (methanol, ethanol, or isopropanol) at low temperature.

[0014] This application discloses the best example of wet-like atomic layer etching (ALE), or wet-like (plasma) ALE, or nanomist (plasma) ALE for damage-free and selective isotropic etching using mist / vapor / plasma at low temperature. The mist-vapor or nanomist can be generated via a non-contact atomizer. The mist-vapor size can be controlled by carrier gas / diluting gas and working pressure of a vacuum chamber. The self-limiting passivation layer can be removed by dissolving it in the nanomist flow or plasma-activated nanomist flow.

[0015] An effect, which is obtained by a representative configuration of the invention disclosed in this specification, is as follows. According to embodiments of this invention, it is possible to provide a new technology of dry etching, named wet-like etching, or wet-like (plasma) etching, or nanomist (plasma) etching for damage-free and selective isotropic etching using mist / vapor / plasma at low temperature, in continuous or in cyclic etching manner. Highly selective etching of metals or metal compounds and other materials can be obtained by different surface reactions with mist or plasma. The modification layer can be removed by dissolving the modified layer in a highly volatile nanomist flow at low temperature, this can minimize the damage as compared with high temperature treatment from thermal ALE. In addition to gas or plasma etchants, using other etchants in form of mist from different precursors (liquid or powder) produced via an atomizer can open a wide-range selection of environment-friendly etchants. Importantly, the intermediate phase between mist and vapor, named mist-vapor phase or nanomist phase, that can maintain the wet properties of liquid phase at the minimal mist size is proposed here for nanodevices applications.

[0016] Figure 1 is a view illustrating an example of floating nanomist-assisted vapor atomic layer etching method or Leidenfrost atomic layer etching method.Figure 2 is a view illustrating an example of plasma-activated nanomist atomic layer etching method.Figure 3 is a view illustrating an example of plasma combined with nanomist atomic layer etching method.Figure 4 is a view illustrating an example of removal of the modified layer by dissolving it in a highly volatile nanomist flow during the wet-like (plasma) atomic layer etching.Figure 5 is a view illustrating an example of formation of nanomist on substrate surface at various substrate temperatures. Depending on the substrate temperature, the nanomist can form on the sample surface with single-phased nanomist at the no boiling state, co-existed bubble / nanomist / vapor at the transition boiling state, and double-phased nanomist / vapor film at the film boiling state.Figure 6 is a view illustrating an example of the nanomist floats on its own vapor cushion at the Leidenfrost point.Figure 7 is a view illustrating an example of wet-like ALE using floating nanomist-assisted vapor film based on the Leidenfrost effect.Figure 8a is a view illustrating methods to form mist / vapor from liquid.Figure 8b is a view illustrating the formation of mist / vapor from a three-component (A, B, and C) liquid mixture.Figure 9 is a view illustrating methods to reduce the mist size and to optimize the mist-vapor size by controlling working pressure of vacuum chamber.Figure 10 is a view illustrating a schematic of a non-contact atomizer using ultrasonic transducer for nanomist generation.Figure 11a is a view illustrating an example of various designs of the precursor canisters or liquid canisters used in the non-contact atomizers for nanomist generation.Figure 11b is a view illustrating an example of various designs of the precursor canisters or liquid canisters used in the non-contact atomizers for nanomist generation.Figure 11c is a view illustrating an example of various designs of the precursor canisters or liquid canisters used in the non-contact atomizers for nanomist generation.Figure 11d is a view illustrating an example of various designs of the precursor canisters or liquid canisters used in the non-contact atomizers for nanomist generation.Figure 12 is a view illustrating the dependence of film thickness of TiAlC on exposure time to (NH4OH, H2O2, H2O) mist obtained from liquid mixture of (NH4OH, H2O2, H2O) by using a non-contact atomizer with mist filter at room temperature and atmospheric pressure.Figure 13 is a view illustrating a mist / vapor / plasma system combined with a vacuum chamber.Figure 14 is a view illustrating a plasma-activated mist / vapor system combined with a vacuum chamber.Figure 15 is a view illustrating mist / vapor / plasma system combined with spectrometers for measuring the reactions between sample surface and mist / vapor / plasma during the etching process.Figure 16 is a view illustrating thermal camera images of the non-contact atomizer that was connected with a vacuum chamber at 20 kPa during the nanomist generation.Figure 17 is a view illustrating the dependence of substrate temperature on film thickness change of TiAlC during the nanomist etching at working pressure of 20 kPa and exposure time of 10 min.Figure 18a is a view illustrating X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, N 1s and Si 2p of pristine TiAlC.Figure 18b is a view illustrating X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, N 1s and Si 2p of nanomist-treated TiAlC samples at working pressure of 20 kPa and exposure time of 10 min without filter at 25 °C.Figure 18c is a view illustrating X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, N 1s and Si 2p of nanomist-treated TiAlC samples at working pressure of 20 kPa and exposure time of 10 min with filter at 25 °C.Figure 18d is a view illustrating X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, N 1s and Si 2p of nanomist-treated TiAlC samples at working pressure of 20 kPa and exposure time of 10 min with filter at 100 °C.Figure 18e is a view illustrating X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, N 1s and Si 2p of nanomist-treated TiAlC samples at working pressure of 20 kPa and exposure time of 10 min with filter at 175 °C.

[0017] The present inventors have attempted to develop the new dry etching technology, named wet-like atomic layer etching, or wet-like (plasma) atomic layer etching, or nanomist (plasma) atomic layer etching at low temperature, that minimizes the damage from sputter effect in plasma ALE, high temperature treatment in thermal ALE during volatilization, and nanostructure damage from wet ALE. As a result, they obtained the following findings. (1) H2O2mist was successfully obtained from the mixture of (H2O2, H2O) at room temperature. The boiling points of H2O2and H2O are 150.2 °C and 100 °C, respectively. (2) (NH4OH, H2O2, and H2O) mist was successfully obtained at room temperature from liquid mixture of (NH4OH, H2O2, and H2O) by using a non-contact atomizer for etching TiAlC. The boiling points of NH4OH, H2O2, and H2O are 37.7 °C, 150.2 °C and 100 °C, respectively. (3) The atomizers were designed for the liquid not contacting the ultrasonic transducer (non-contact atomizer) to avoid the corrosive liquids (etchants) to react with ultrasonic transducer. (4) The materials, the thickness, and the shape of the liquid (or precursor) canister used in the non-contact atomizer were investigated and optimized to effectively produce the mist. (5) The non-contact atomizer was designed with mist filter and to obtain uniform mist size for uniform etching. (6) TiAlC was etched by (NH4OH, H2O2, and H2O) nanomist generated from the non-contact atomizer with filter combined with a vacuum chamber that is controlled at medium pressure. (7) When heated the TiAlC substrate to the Leidenfrost point of (NH4OH, H2O2, and H2O) mixture, the TiAlC was etched by floating nanomist-assisted vapor of (NH4OH, H2O2, and H2O).

[0018] The best example of this invention will be described with reference from Fig. 1 to Fig. 18e.

[0019] <Example Process 1> The first embodiment will be described with the reference from Fig. 1 to Fig. 4. The description will be given of examples of new dry etching technology, named wet-like ALE, or wet-like (plasma) ALE, or nanomist (plasma) ALE at low temperature, that minimizes the damage from sputter effect in plasma ALE and high temperature treatment in thermal ALE during volatilization, and nanostructure damage from wet ALE.

[0020] Figure 1 is a view illustrating an example of floating nanomist-assisted vapor atomic layer etching method or Leidenfrost atomic layer etching method. The “floating nanomist-assisted vapor” will be fully explained later as illustrating in Figure 7 by using Leidenfrost effect. Sample surface is first exposed in floating nanomist-assisted vapor film for surface modification and form the liquid-like layer, then the liquid-like layer is removed by dissolving it in a highly volatile nanomist flow such as nanomist of methanol, ethanol, and isopropanol.

[0021] Figure 2 is a view illustrating an example of floating wire assisted vapor plasma-activated nanomist atomic layer etching method. Sample surface is first exposed in plasma-activated nanomist for surface modification and form the liquid-like layer, then the liquid-like layer is removed by dissolving it in a highly volatile nanomist flow such as nanomist of methanol, ethanol, and isopropanol.

[0022] Figure 3 is a view illustrating an example of plasma combined with nanomist atomic layer etching method. Sample surface is first exposed to plasma for surface modification and form the modification layer, then the modification layer is removed by dissolving it in a highly volatile nanomist flow such as nanomist of methanol, ethanol, and isopropanol.

[0023] Figure 4 is a view illustrating an example of removal of the modified layer by dissolving it in a highly volatile nanomist flow during the wet-like (plasma) atomic layer etching. After modification layer was formed on the sample surface, it is removed by dissolving it in a highly volatile nanomist flow such as nanomist of methanol, ethanol, and isopropanol.

[0024] <Example Process 2> The second embodiment will be described with the reference from Fig. 5 to Fig. 9. The nanomist properties and the formation of nanomist on substrate with temperature dependence will be explained with the formation of floating nanomist-assisted vapor at the Leidenfrost point for wet-like ALE application.

[0025] Figure 5 is a view illustrating an example of formation of nanomist on substrate surface at various substrate temperatures. Depending on the substrate temperature, the nanomist formation can be different. At the no boiling state, the substrate temperature is less than the boiling temperature, and single-phased nanomist is formed. Wet-like etching by the liquid-like layer made from nanomist can be obtained. It is not proper to apply for nanodevices because the liquid-like layer made from nanomist behaves as a liquid layer with surface tension, similar in the ordinal wet etching, resulting in the issue of pattern collapse in nanodevices. There is no need to point it out, even under this state, the present nanomist technology can be applied to applications other than nanodevices, just like traditional wet etching.

[0026] At the transition boiling state, the substrate temperature is no less than the boiling point and less than the Leidenfrost point, and the co-existed bubble / nanomist / vapor is formed. The gas bubbles form inside the co-existed nanomist and explode to form vapor. There are several issues to properly control for uniformity in etching in this state. Although the present invention does not deeply deal with these issues, these issues will be able to be solved by some optimizations in composition of the raw material for the nanomist.

[0027] At the film boiling state, the substrate temperature is no less than the Leidenfrost point, the double-phased nanomist / vapor is formed. The nanomist stably floats on a continuous and uniform cushions made of its own vapor at the Leidenfrost point with frictionless motion. In this state, uniform etching can be easily obtained by the continuous and uniform vapor film. Wet-like ALE using floating nanomist-assisted vapor film to form an ultra-thin reaction film (modified layer) on sample surface can be obtained.

[0028] Figure 6 is a view illustrating an example of a nanomist floating on a stable cushion made of its own vapor at the Leidenfrost point. At the Leidenfrost point, the nanomist hovers on the substrate surface for the longest lifetime. The nanomist floats on its own vapor cushion over the whole sample surface with frictionless motion to form an ultra-thin liquid-like layer. Uniform wet-like etching can be obtained without pattern collapsing by floating nanomist-assisted vapor. Due to slow evaporation of floating nanomist and longer resident time of the vapor layer even at the higher temperature range than its boiling point, the reaction rate increases by the acceleration effect of the higher temperature. Higher reaction rate can be also obtained because the consumed etchant molecule from the vapor layer can be immediately compensated by the floating nanomist with higher-temperature-accelerated mass flux between the nanomist and the vapor layer. In another word, when the substrate temperature reaches the Leidenfrost point, the nanomist works as a temporary etchant supplier for the vapor film to directly react with the sample surface. In addition, a higher number of etchant molecules were kept on the sample surface by the volume or shape of the nanomist and pressed by the weight or mass of nanomist, that reduces the etchant lost during flowing out from the sample surface.

[0029] Figure 7 is a view illustrating an example of wet-like ALE using floating nanomist-assisted vapor film based on the Leidenfrost effect. The wet-like ALE process consists of two steps including surface modification by floating nanomist-assisted vapor A in the first step, and removal of reaction layer by floating nanomist-assisted vapor B in the second step.

[0030] In the first step, the nanomist floats on its own vapor cushion over the whole sample surface at the Leidenfrost point with frictionless motion. A stable vapor film A is formed under the floating nanomist, and plays as a role of a thermal insulator film that reduces the heat transfer from substrate surface to the nanomist, and therefore, a slow evaporation rate of the nanomist will support the nanomist to obtain the longest lifetime. At the Leidenfrost point, the nanomist presses its own vapor cushion film to react with sample surface with highest contact area for the longest time, just like a reaction in a pressure cooker, this is an optimal condition to form an ultra-thin reaction film in the shortest time.

[0031] In the second step, removal of reaction layer is done by floating nanomist-assisted vapor B. The reaction product desorbs from the sample surface and dissolves in the floating nanomist B and is removed together with the floating nanomist B. The raw material with highly volatility and low reactivity is desirable for nanomist B. If the nanomist B easily reacts with the sample surface, the unwanted damage on the substrate may occur. Frictionless-motion nanomist or non-contact nanomist after absorbing the reaction product could be removed easily as compared with the high-contact nanomist at no boiling point state, resulting in a clean surface and a controllable cyclic process.

[0032] In order to lower the Leidenfrost point, metastable Leidenfrost nanomist can be obtained by increasing the surrounding temperature by baking the chamber to compensate the heat loss of the mist surface (top of the mist), or reducing the working pressure, or reducing the mist size.

[0033] Figure 8a is a view illustrating methods to form nanomist from liquid. For etching application, mist or vapor form are required. To generate the mist or vapor from a liquid, heating or boiling the liquid is a traditional way. Another traditional way is connected the liquid canister with a vacuum chamber and control the vacuum chamber at vapor pressure to obtain the vapor. Ultrasonic vibration can be used at several hundred kilohertz frequency (kHz) to several megahertz frequency (MHz) to generate mist. Additional carrier gas also can be used to make bubbles and control the mist direction.

[0034] Figure 8b is a view illustrating the formation of mist / vapor from a three-component liquid (A, B, and C) mixture. For the multi-component mixtures such as (NH4OH, H2O2, and H2O) with different boiling points and vapor pressures for each single phase and being easy to be decomposed even at low temperature, ultrasonic vibration from an atomizer is a suitable method to obtain the “cool” mist / vapor at room temperature. Vaporization of the three-component (A, B, C) mixture can form the vapor of each component that may exist separately from each other without any ionic bond. The combination effects produced from mixing these three chemical components (A, B, and C) in wet phase will be lost. In case of nanomist form, an intermediate phase between mist and vapor (nanomist) can maintain the component of three chemicals A, B, and C with the presence of ionic interactions between these three components, so the combination effects produced from mixing these three chemical components in wet phase are maintained in minimal mist size. In the present invention, the desirable mist size is from 0.5 nm to 10 nm. If the mist size is smaller than 0.5 nm, it is difficult to maintain intermediate phase between mist and vapor due to loss of combination effects produced from mixing these three chemical components in wet phase. And if the mist size is larger than 10 nm, the mist, especially the micromist, will lose its vapor properties, and it is difficult to maintain intermediate phase between mist and vapor. If the mist-vapor phase can be obtained, uniformity in mist size and chemical ratio control in each mist droplet can be achieved, leading to an etching with uniformity which is suitable for nanodevices. The micromist is a cluster of components including three chemicals (A, B, C). The combination effects produced from mixing these three chemical components in wet are maintained with the presence of ionic interactions between these three components; however, it is not suitable for nanodevices applications due to the generation of large-size and non-uniform mists (> 100 nm; namely “over sub-micron” size).

[0035] In order to confirm the mist size, the mist was introduced into a wide-range particle spectrometer. In the present invention, the inventor used a WPS, Model 1000XP made by MSP. Although there is no need to point it out, other known particle spectrometer also can be used for this purpose. For the measurement in the 10 to 10,000 nm range, the mist was set at a certain flow rate, for example 1.00 liter per minute (standard little per minute; slm), of which 0.7 slm passes through a laser particle spectrometer (LPS) for size analysis by laser light scattering. The remaining 0.30 slm then passes through a differential mobility analyzer (DMA) and a condensation particle counter (CPC) to measure aerosol particle size to a lower limit of 10 nm. Measurement to a lower size limit of 5 nm is accomplished by increasing the aerosol flow rate through the DMA and CPC to 0.45 slm. The total mist flow through the WPS thereby also increases to 1.15 L / min.

[0036] The uniformity by nanomist etching reaction with sample surface is analyzed by atomic force microscopy (AFM). The surfaces of samples including pristine sample, nanomist-modified surface sample, and nanomist-etched surface sample were observed and compared. If the mist size is large enough and such micromist contacts on the sample surface with high surface tension, ultra-thin film is not able to form as previously mentioned in the explanation for the left figure of Figure 5, large holes on the sample surface will remain and can be seen clearly by AFM. And if the mist size is small enough such as in the range from 0.5 nm to 10 nm, the AFM image of the etched surface showed uniformed flatness without any large hole. These nanomist, with diameter range from 0.5 nm to 10 nm, have extraordinarily lowered surface tension by nano-size effect, which is well described in NPL 2. These nanomists may react with sample surface without any direct-wet contact as mentioned in the explanation for the right figure of Figure 5.

[0037] Figure 9 is a view illustrating methods to obtain the desirable mist size and to optimize the mist-vapor phase by controlling working pressure of vacuum chamber. To maintain the wet properties of mist (liquid phase) and to approach the small size of vapor for nanodevice applications, controlling the mist size is important as above-mentioned range (0.5 nm - 10 nm). To obtain the nanomist with the desirable droplet size, sonic frequency from several hundred kilohertz to several megahertz is preferred. More concretely, the frequency in the range of 1.0 - 10 MHz is more preferred. Adding carrier gas and dilution gas (N2, Ar, or He) also can reduce the mist size. It is desirable that the generated intermediate phase between mist and vapor or nanomist phase is used under the condition that the sample surface temperature was controlled to obtain the Leidenfrost effect. At the Leidenfrost point, the sample surface reacts with the floating nanomist-assisted vapor to form an ultra-thin liquid-like layer. In this embodiment, controlling working pressure at optimal pressure (medium pressure) is supposed to obtain the mist-vapor phase.

[0038] To introduce the mist to the nanopatterns of nanodevices, in addition to the mist size, the surface tension of mist is also very important. The surface tension of the mist depends on the mist diameter and the surface tension of the mist with a diameter of 10 nm or less becomes too small to be measured, which is well described in NPL 2. Moreover, when the mist has a diameter of 10 nm or less and under the condition of the Leidenfrost effect, the mist droplet will not attach on the surface of the device and the surface tension of the mist will not affect the nanopattern of the nanodevice. Therefore, in the present embodiment, the nanomist with the desirable droplet size will minimize the nanopattern collapse, and hence, increasing the reproductivity of making nanodevices. The surface tension of the mist can be reduced at lower size. If the mist-vapor phase can be achieved, the nanomist can reach minimal size with low surface tension, that brings potential for etching nanodevices. In addition, choosing of high-volatile (low boiling point) mist such as methanol, ethanol, or isopropanol mist with low surface tension, can be considered as good candidates to dissolve the residues or modified layer without remaining any residues. Dissolution and removal (etching / cleaning) can occur at the same time.

[0039] <Example Process 3> The description will be given of an example in producing mist from single and multi-liquid mixtures by a non-contact atomizer with the reference from Fig. 10 to Fig. 12.

[0040] Figure 10 is a view illustrating a schematic of a non-contact atomizer using ultrasonic transducer to generate nanomist, which is suitable for this invention. Ultrasonic vibration can be used at several hundred kilohertz frequency (100 kHz-950 kHz) to several megahertz (1.6 MHz-2.4 MHz) to generate mist. To obtain nanomist, megasonic frequency is preferred and the most preferable frequency is 1.7 MHz or 2.4 MHz due to practical availability of the corresponding ultrasonic wave generator. Because this is the non-contact atomizer, the ultrasonic wave needs to transmit through water as a medium and a coolant and then through the precursor canister or liquid canister to the liquid as a raw material of the etchant. Therefore, investigation and optimization of the liquid canister material, thickness, and shape are important.

[0041] For the liquid canister material, polypropylene and some polymer-based materials show the good effect in generate mist compared with glass material; however, when the liquid level inside the canister is very low, polymer-based materials may get melted due to their low melting points. Therefore, in the present invention, glass is one of the much better materials than polymer-based materials to be used for the liquid canister due to its high melting point and high chemical resistance.

[0042] The shape of the liquid canister should be rounded to maximize the efficiency of mist generation in the present invention by focusing the ultrasonic wave energy to obtain the maximum transmission energy at the liquid surface. When this transmission energy exceeds the mist ignition threshold, mist is generated. When the shape of the bottom of the liquid canister is flat, transmission energy will expand more equally on the liquid surface, the efficiency of mist generation is reduced with more generation of large droplet, and heat loss by canister wall is increased.

[0043] Thickness of the liquid canister, especially the thickness of the bottom part where the ultrasonic wave transmission is very important to effectively achieve to generate the desirable nanomist for the present invention. Aluminum metal is not a good material to transmit the ultrasonic wave; however, the aluminum foil with the thickness around 10 μm to 100 μm can generate the mist effectively. In this invention, glass is a chosen material for making liquid canister. Thin glass canister with the bottom thickness in the range of 0.3 mm to 2 mm is preferable to generate the nanomist with the desirable diameter for the present invention. If the glass canister with the bottom thickness higher than 2 mm, efficiency to generate the mist is much decreased, mainly some waves occurred on the liquid surface and serious heat loss by canister bottom wall. If the glass canister with the bottom thickness less than 0.3 mm, it is difficult during making the canister, and the canister is easy to be broken.

[0044] In order to obtain uniform nanomist and avoid large droplets, an additional side-port filter is designed. This side port is designed to face opposite with the liquid canister center and face the canister wall, the mists with the unwanted diameter size are excluded, and the desired nanomist can pass through the filter. Side-port filter can have a port inner diameter in a range of 5 mm-15 mm.

[0045] A filter made by a hydrophobic material or a water-proof coated material such as polytetrafluoroethylene (PTFE) with the mesh size is from 0.1 mm to 1 mm also can be used to avoid the large droplet and filter uniform nanomists.

[0046] An additional membrane filter made by a hydrophobic material or a water-proof coated material such as polytetrafluoroethylene (PTFE) with the mesh size in the range of 100 nm to 500 nm can be used to obtain the smaller and uniform nanomist. For the nanomist of an aqueous liquid mixture such as (NH4OH, H2O2, and H2O), mist size control is very important in the present invention to control the component percentage of each chemical. The component percentage may change when the mist size changed. In order to obtain uniform etching, uniformity of nanomist size should be controlled with a mist filter.

[0047] Each of Figure 11a to 11d is a view illustrating an example of various types of the precursor canisters or liquid canisters made of glass used in the non-contact atomizers for desirable nanomist generation, respectively. Four types of the liquid canister used in the non-contact atomizers are presented here.

[0048] Type 1 (Figure 11a) is a liquid canister made of glass used in the non-contact atomizer to generate desirable nanomist with carrier and dilution gas (He, Ar, or N2). A side-port filter is designed with a port inner diameter ranged from 5 mm to 10 mm to avoid the large droplets generated as a by-product of ultrasonic transducer. A refilled port is designed at the top of the canister for adding the liquid. The liquid level is controlled in the range of 20% to 40% of the canister height to avoid the large droplet and mist condensation to the side-port filter. If the liquid level is higher than 40%, more condensation to the side-port will occurs. In the case of the liquid level is less than 20%, although it is easier to generate the mist, the precursors need to be refilled more frequently. The liquid level is controlled at 30% of the canister height is preferred. In order to optimize the ultrasonic energy transmission to the liquid surface to maximize the mist generation efficiency, the optimal wave energy transmission point M need to be optimized. Optimal wave energy transmission point M is the point that can receive the maximum ultrasonic wave energy transmission to the liquid surface to exceed the mist ignition energy threshold, and it is the starting point (ignition mist point) for generating the mist. It is located on the liquid level line. At the center of the liquid level line, due to the rounded shape of the canister bottom, more confined ultrasonic energy wave can be obtained at the liquid surface. However, the ultrasonic energy transmission to the liquid surface is not optimal owing to the liquid level is maximum and the bottom center of the canister is thicker caused by canister making process. The optimal wave energy transmission point M is located far from the center of the liquid level line around 5 mm to 20 mm in this invention. The side-port position (MS line) is designed far from the normal line (MV line) to optimize wave energy transmission point M of the liquid surface an angle α from 30° to 60° to avoid the large and warm droplets produced at the same time with nano and cool mist. The center of ultrasonic transducer is placed on the MV line. For long-time mist generation, it is better to make a water-proof coating (hydrophobic coating) on the surface of the side-port filter to reduce the mist condensation problem. These water-proof coating repel the aqueous mist generated by the atomizer.

[0049] Type 2 (Figure 11b) is a liquid canister made of glass used in the non-contact atomizer to generate nanomist with carrier and dilution gas (He, Ar, or N2). The carrier / dilution gas port or the nanomist port can be used to refill the liquid. The liquid level is controlled in the range of 20% to 40% of the canister height to avoid the large droplet and mist condensation to the nanomist port. If the liquid level is higher than 40%, more condensation to the nanomist port will occurs. In the case of the liquid level is less than 20%, although it is easier to generate the mist, the precursors need to be refilled more frequently. The liquid level is controlled at 30% of the canister height is preferred. A PTFE filter with the mesh diameter ranged from 0.1 mm to 1 mm is placed at near the mist outlet line to exclude large droplets for obtaining uniform nanomists. If the mesh diameter is less than 0.1 mm, more condensation occurs. If the mesh diameter is more than 1 mm, more ununiform size and larger droplet are produced. The PTFE filter with the mesh diameter of 0.5 mm is preferred to use in this invention.

[0050] Type 3 (Figure 11c) is a liquid canister made of glass used in the non-contact atomizer to generate nanomist with carrier and dilution gas (He, Ar, or N2). The carrier / dilution gas port or the nanomist port can be used to refill the liquid. A side-port filter is designed with a port inner diameter ranged from 5 mm to 15 mm to avoid the large droplets produced from ultrasonic transducer. The liquid level is controlled in the range of 20% to 40% of the canister height to avoid the large droplet and mist condensation to the side-port filter. If the liquid level is higher than 40%, more condensation to the side-port will occurs. In the case of the liquid level is less than 20%, although it is easier to generate the mist, the precursors need to be refilled more frequently. The liquid level is controlled at 30% of the canister height is preferred. Other problems occur such as reduction of mist generation efficiency, more heat loss on the canister wall, and higher amount of large-sized droplet. In order to optimize the ultrasonic energy transmission to the liquid surface to maximize the mist generation efficiency, the optimal wave energy transmission point M need to be optimized. Optimal wave energy transmission point M is the point that can receive the maximum ultrasonic wave energy transmission to the liquid surface to exceed the mist ignition energy threshold, and it is the starting point (ignition mist point) for generating the mist. It is located on the liquid level line. At the center of the liquid level line, due to the rounded shape of the canister bottom, more confined ultrasonic energy wave can be obtained at the liquid surface. However, the ultrasonic energy transmission to the liquid surface is not optimal owing to the liquid level is maximum and the bottom center of the canister is thicker caused by canister making process. The optimal wave energy transmission point M is located far from the center of the liquid level line around 10 mm to 20 mm in this invention. The side-port position (MS line) is designed far from the normal line (MV line) to optimize wave energy transmission point M of the liquid surface an angle α from 30° to 60° to avoid the large and warm droplets produced at the same time with nano and cool mist. The center of ultrasonic transducer is placed on the MV line. For long-time mist generation, it is better to make a water-proof coating on the surface of the side-port filter to reduce the mist condensation problem. These water-proof coating repel the aqueous mist generated by the atomizer.

[0051] Type 4 (Figure 11d) is a liquid canister made of glass used in the non-contact atomizer to generate nanomist with carrier and dilution gas (He, Ar, or N2). The carrier / dilution gas port or the nanomist port can be used to refill the liquid. A side-port filter is designed with a port inner diameter ranged from 5 mm to 15 mm to avoid the large droplets produced from ultrasonic transducer. The liquid level is controlled in the range of 20% to 40% of the canister height to avoid the large droplet and mist condensation to the side-port filter. If the liquid level is higher than 40%, more condensation to the side-port will occurs. In the case of the liquid level is less than 20%, although it is easier to generate the mist, the precursors need to be refilled more frequently. The liquid level is controlled at 30% of the canister height is preferred. Other problems occur such as reduction of mist generation efficiency, more heat loss on the canister wall, and higher amount of large-sized droplet. In order to optimize the ultrasonic energy transmission to the liquid surface to maximize the mist generation efficiency, the optimal wave energy transmission point M need to be optimized. Optimal wave energy transmission point M is the point that can receive the maximum ultrasonic wave energy transmission to the liquid surface to exceed the mist ignition energy threshold, and it is the starting point (ignition mist point) for generating the mist. It is located on the liquid level line. At the center of the liquid level line, due to the rounded shape of the canister bottom, more confined ultrasonic energy wave can be obtained at the liquid surface. However, the ultrasonic energy transmission to the liquid surface is not optimal owing to the liquid level is maximum and the bottom center of the canister is thicker caused by canister making process. The optimal wave energy transmission point M is located far from the center of the liquid level line around 10 mm to 20 mm in this invention. The side-port position (MS line) is designed far from the normal line (MV line) to optimize wave energy transmission point M of the liquid surface an angle α from 30° to 60° to avoid the large and warm droplets produced at the same time with nano and cool mist. The center of ultrasonic transducer is placed on the MV line. A PTFE filter with the mesh diameter ranged from 0.1 mm to 1 mm is placed at near the mist outlet line to exclude large droplets for obtaining uniform nanomist. If the mesh diameter is less than 0.1 mm, more condensation occurs. If the mesh diameter is more than 1 mm, more ununiform size and larger droplet are produced. The PTFE filter with the mesh diameter of 0.5 mm is preferred to use in this invention. For long-time mist generation, it is better to make a water-proof coating on the surface of the side-port filter to reduce the mist condensation problem. These water-proof coating repels the aqueous mist generated by the atomizer.

[0052] Figure 12 is a view illustrating an experimental result of the dependence of film thickness on exposure time to the nanomist of 3-component aqueous liquid mixture of NH4OH, H2O2, and H2O at room temperature and atmospheric pressure. Film thickness of TiAlC film was reduced when increasing the exposure time to the nanomist. The film thickness was estimated by using ellipsometry. The etch rate of TiAlC by (NH4OH, H2O2, and H2O) mist is 0.15 nm / min.

[0053] <Example Process 4> A fourth embodiment will be described with the reference from Fig.13. The description will be given of examples of mist / vapor / plasma systems combined with vacuum chambers for surface modification and etching purpose.

[0054] Figure 13 is a view illustrating a mist / vapor / plasma system combined with a vacuum chamber. The room-temperature nanomist obtained from non-contact atomizer is flowed to the vacuum chamber. The mist size can be controlled by adding a carrier and dilution gas (He, Ar, or N2) that avoid the recombination of nanomist and by changing working pressure of the vacuum chamber. A plasma source such as capacitively coupled plasma, inductively coupled plasma, microwave plasma, and floating wire-assisted plasma can be used for plasma treatment in the vacuum chamber. A process combined multi-steps for plasma or nanomist treatment (surface modification) and nanomist treatment (removal of the modified layer by dissolving it in a highly volatile nanomist flow) can be done. Working pressure can be controlled at medium pressure (0.2 kPa-50 kPa), in which the nanomist flow behaves as a fluid (maintaining the wet properties) and the mist size can be controlled into the preferable value range for etching nanodevices. Substrate temperature can be controlled by using hitherto known method such as a circulator or an IR lamp. By heating the substrate to adequate temperature range at which the Leidenfrost effect will appear, every droplet in the nanomist will not attach on the surface of the device, and the surface tension of the mist will not affect nanopattern of nanodevice. Although the nanomist in the chamber have beam scattering properties, the plasma properties can be measured by using several kinds of spectrometers such as optical emission spectrometer with some efforts.

[0055] Figure 14 is a view illustrating a plasma-activated mist / vapor system combined with a vacuum chamber. A remote plasma source is introduced to the atomizer at the mist part to activate the nanomist by incorporating some radicals to the nanomist. For example, remote oxygen plasma can generate oxygen radical O* that could incorporate into (NH4OH and H2O) to form (NH4OH, O*, and H2O) to replace H2O2in (NH4OH, H2O2, and H2O) mist. H2O2solution, especially at high concentration (more than 30%) is corrosive and explosive, hence, a replaced gas or plasma seems to be preferred for practical use. The plasma (He plasma or Ar plasma) also could activate the mist to form negative charged mist that could be driven by an electric field. By applying a positive charge to the sample surface, the negative charged mist can approach the sample surface more uniform and effectively. The obtained plasma-activated nanomist from non-contact atomizer is flowed to the vacuum chamber. The mist size can be controlled by adding a carrier and dilution gas (He, Ar, or N2) that avoid the recombination of nanomist and by changing working pressure of vacuum chamber. Working pressure can be controlled at medium pressure (0.2 kPa-50 kPa), in which the nanomist flow behaves as a fluid (maintaining the wet properties) and the mist size can be controlled into the preferable value range for etching nanodevices. Substrate temperature can be controlled by hitherto known method such like a circulator or an IR lamp.

[0056] Figure 15 is a view illustrating a mist / vapor / plasma system that is combined with spectrometers as follows: (1) an optical emission spectrometer (OES) for measuring the plasma properties, (2) a spectroscopic ellipsometer (SE) for analysis of sample surface modification and the change of sample film thickness, (3) a Fourier-transform infrared spectrometer (FTIR) for analysis of sample surface modification, (4) an X-ray photoelectron spectrometer (XPS) for analysis of sample surface modification, (5) a quadrupole mass spectrometer (QMS) for analysis of nanomist / plasma composition and volatile products from the sample surface during the its reaction with mist / plasma, or (6) A thermal desorption spectroscopy (TDS) for analysis of the desorption products that are produced by heating nanomist / vapor / plasma treated sample surface.

[0057] The room-temperature nanomist obtained from non-contact atomizer is flowed to the vacuum chamber. A plasma source is introduced to the atomizer at the mist part to activate the nanomist by incorporating some radicals to the nanomist. For example, remote oxygen plasma can generate oxygen radical O* that could incorporate into (NH4OH and H2O) to form (NH4OH, O*, and H2O) to replace H2O2in (NH4OH, H2O2, and H2O) mist. The plasma (He plasma or Ar plasma) also could activate the nanomist to form negative charged mist that could be driven by an electric field. The obtained plasma-activated nanomist from non-contact atomizer is flowed to the vacuum chamber. The mist size can be controlled by adding a carrier and dilution gas (He, Ar, or N2) that avoid the recombination of nanomist and by changing working pressure of vacuum chamber. Working pressure can be controlled at medium pressure (0.2 kPa-50 kPa), in which the nanomist flow behaves as a fluid (maintaining the wet properties) and the mist size can be controlled into the preferable value range for etching nanodevices. A plasma source such as capacitively coupled plasma, inductively coupled plasma, microwave plasma, and floating wire-assisted plasma can be used for plasma treatment. A process combined multi-steps for plasma-activated nanomist treatment (surface modification) and nanomist treatment (removal of the modified layer by dissolving it in a highly volatile nanomist flow) can be done. Substrate temperature can be controlled by hitherto known method such like a circulator or an IR lamp.

[0058] Figure 16 is a view illustrating some typical experimental results of thermal camera images of the non-contact atomizer (type 2 in Figure 12) that was connected with a vacuum chamber at 20 kPa during the nanomist generation. By using the non-contact atomizer to produce nanomist, the temperatures of liquid and mist are near room temperature and insignificant changed during the mist generation. The temperature of liquid is less than 30 °C and that of mist is less than 30 °C after 15 min of nanomist generation.

[0059] Figure 17 is a view illustrating the dependence of substrate temperature on film thickness change of TiAlC during the nanomist etching at working pressure of 20 kPa and exposure time of 10 min. When increasing the substrate temperature, higher etch rate is obtained. At the temperature of 175 °C, the highest etch rate of TiAlC film is 0.02 nm / min. 175 °C is considered as the Leidenfrost point of the nanomist produced from aqueous liquid mixture of (NH4OH, H2O2, and H2O) at 20 kPa, in which the TiAlC surface was etched by the floating nanomist-assisted vapor of (NH4OH, H2O2, and H2O) mixture.

[0060] Each of Figures 18a to 18e is a view illustrating several typical experimental results on X-ray photoelectron spectra of Ti 2p, Al 2p, C 1s, O 1s, and N 1s of (a) pristine TiAlC, and nanomist-treated TiAlC samples at working pressure of 20 kPa and exposure time of 10 min for the cases (b) without filter at 25 °C, (c) with filter at 25 °C, (d) with filter at 100 °C, (e) with filter at 175 °C, respectively. Without PTFE filter, surface oxidation occurs on TiAlC surface, and Ti(Al)-C bond is replaced by Ti(Al)-O bond, and N 1s spectrum is detected, that is from ammonium hydroxide residue. In case of using PTFE filter, although etching occurs at 100 °C and 175 °C, surface of etched samples is cleaned as the surface of pristine sample. The residue of mist may be not remained in case of using PTFE filter during continuous mist etching.

Claims

1. An etching processing method comprising: a first step of generating a phase with intermediate properties between mist liquid phase and vapor phase by using atomizer, a second step of exposing sample surface to the phase having a first composition with intermediate properties between mist liquid phase and vapor phase to generate a surface modified layer, a third step of exposing the surface modified layer generated in the second step to the phase having a second composition with intermediate properties between mist liquid phase and vapor phase, and a forth step of heating the substrate surface prior to the second or the third step so that the substrate surface temperature is higher than a boiling point of each component of the first composition or the second composition, respectively.

2. An etching processing method comprising; a first step of generating a phase with intermediate properties between mist liquid phase and vapor phase by using non-contact atomizer with mist filter, a second step of exposing sample surface to the phase having a first composition with intermediate properties between mist liquid phase and vapor phase to generate a surface modified layer, a third step of exposing the surface modified layer generated in the second step to the phase having a second composition with intermediate properties between mist liquid phase and vapor phase in order to remove the surface modified layer in the second step by dissolving the surface modified layer in the phase, and a forth step of heating the substrate surface prior to the second or the third step so that the substrate surface temperature is higher than a boiling point of each component of the first composition or the second composition, respectively.

3. The etching processing method according to claim 1 or claim 2, the plasma exposure is performed to the sample surface.

4. The etching processing method according to claim 1 or claim 2, the plasma activation was performed to the phase with intermediate properties between mist liquid phase and vapor phase.

5. The etching processing method according to claim 1 or claim 2, wherein the phase with intermediate properties between mist liquid phase and vapor phase contains nano-droplets with diameters between 0.5 nm and 10 nm.

6. The etching processing method according to claim 1 or claim 2, wherein the atomizer is a kind of ultrasonic atomizer, and the ultrasonic vibration of the ultrasonic atomizer is in the range of several hundred kilohertz to several megahertz to be operated.

7. The etching processing method according to claim 2, wherein the non-contact atomizer has a liquid canister made of rounded glass with bottom thickness in the range of 0.3 to 2.0 mm.

8. The etching processing method according to claim 2, wherein the non-contact atomizer is designed to have a side-port filter on the side-port position of the atomizer to avoid the large and warm droplets produced at the same time with nano and cool mist.

9. The etching processing method according to claim 8, wherein the side-port position is placed far from the normal line of the liquid surface at the mist ignition point an angle from 30° to 60° to avoid the large and warm droplets produced at the same time with nano and cool mist.

10. The etching processing method according to claim 8, wherein the side-port filter has an inner diameter in the range of 5 mm to 15 mm.

11. The etching processing method according to claim 2, wherein the non-contact atomizer has a mist filter to avoid the large and warm droplets produced at the same time with nano and cool mist and the mist filter is placed face directly liquid or precursor surface.

12. The etching processing method according to claim 11, wherein the mist filter has a mesh diameter in the range of 0.1 mm to 1 mm.

13. The etching processing method according to claim 11 or claim 12, wherein the mist filter has a surface made of a hydrophobic material.

14. The etching processing method according to claim 13, wherein the mist filter is a PTFE filter.

15. The etching processing method according to claim 2, wherein the non-contact atomizer has a membrane mist filter to obtain an uniform nanosized mist and the mist filter is placed in a mist outlet line.

16. The etching processing method according to claim 15, wherein the membrane mist filter has a mesh size in the range of 100 nm to 500 nm.

17. The etching processing method according to claim 15 or claim 16, wherein the membrane mist filter has surface made of hydrophobic material.

18. The etching processing method according to claim 17, wherein membrane mist filter is a PTFE membrane filter.

19. The etching processing method according to claim 7, wherein the liquid canister is filled by a liquid with a controlled level to perform effective mist generating and preventing mist condensation.

20. The etching processing method according to claim 19, wherein the liquid canister is filled by the liquid in the range of 20% to 40% of the liquid canister height.

21. The etching processing method according to claim 3, wherein the plasma exposure is performed to the sample surface for surface modification and form the modification layer.

22. The etching processing method according to claim 1 or claim 2, wherein the phase with intermediate properties between mist liquid phase and vapor phase is generated from the H2O2containing aqueous mixture.

23. The etching processing method according to claim 1 or claim 2, wherein the phase with intermediate properties between mist liquid phase and vapor phase is generated from any one of the following precursors: multi-component aqueous liquid mixture with different boiling points, aqueous liquid containing corrosive material, aqueous liquid containing material that is easy to be decomposed even at low temperature, and aqueous liquid containing high boiling point material.

24. The etching processing method according to claim 1 or claim 2, wherein the substrate surface temperature is heated up to the Leidenfrost point of the liquid filled in a liquid canister of the atomizer.

25. The etching processing method according to claim 24, the sample surface is modified by a floating nanomist-assisted vapor to form a liquid-like modified layer, and then the surface modified layer is removed by another floating nanomist-assisted vapor.

26. A semiconductor manufacturing system comprising: a vacuum chamber, a non-contact atomizer to obtain a phase with intermediate properties between mist liquid phase and vapor phase made from a liquid filled in a liquid canister, a carrier gas line and a gas flow controller both of which are connected to the non-contact atomizer, a working pressure controller to set the vacuum chamber at medium pressure, in which the phase with intermediate properties between mist liquid phase and vapor phase behaves as a fluid, an infrared lamp to control the desorption of the modified layer, a heating and cooling circulator to control substrate temperature, and a spectrometer to measure in the vacuum chamber.

27. A semiconductor manufacturing system comprising: a vacuum chamber, a non-contact atomizer to obtain a phase with intermediate properties between mist liquid phase and vapor phase made from a liquid filled in a liquid canister, a carrier gas line and a gas flow controller both of which are connected to the non-contact atomizer, a plasma source for plasma exposure, a working pressure controller to set the vacuum chamber at medium pressure, in which the phase with intermediate properties between mist liquid phase and vapor phase behave as a fluid, an infrared lamp to control the desorption of the modified layer, a heating and cooling circulator to control substrate temperature, and a spectrometer to measure in the vacuum chamber.

28. The semiconductor manufacturing system according to claim 27, wherein the plasma source for plasma exposure comprises a floating wire-assisted plasma source.

29. A semiconductor manufacturing system according to claim 28, a floating wire-assisted plasma is used to activate the phase with intermediate properties between mist liquid phase and vapor phase to form negative charged mist.

30. The semiconductor manufacturing system according to claim 29, the sample surface was applied the positive charge to attract negative charged mist effectively.

31. The semiconductor manufacturing system according to the claim 26 or claim 27, wherein the spectrometer is selected from any of the following: an optical emission spectrometer (OES) for measuring the plasma properties, a spectroscopic ellipsometer (SE) for analysis of sample surface modification and the change of sample film thickness, a Fourier-transform infrared spectrometer (FTIR) for analysis of sample surface modification, an X-ray photoelectron spectrometer (XPS) for analysis of sample surface modification, a quadrupole mass spectrometer (QMS) for analysis of nanomist / plasma composition and volatile products from the sample surface during the its reaction with mist / plasma, and a thermal desorption spectroscopy (TDS) for analysis of the desorption products that are produced by heating nanomist / vapor / plasma treated sample surface.

32. The semiconductor manufacturing system according to claim 26 or claim 27, wherein the substrate temperature is heated up to the Leidenfrost point of the liquid filled in the liquid canister.

33. A processing method comprising the steps of: modifying a sample surface by a first floating nanomist-assisted vapor, in which a first processing gas including nanomist with diameter less than a predetermined value generated from liquid of a first composition is supplied, and removing the modified layer from the sample surface by a second floating nanomist-assisted vapor, in which a second processing gas including nanomist with diameter less than the predetermined value generated from liquid of a second composition is supplied.

34. The processing method according to claim 33, wherein diameter of the nanomist included the first processing gas or the second processing gas is less than 10nm.

35. The processing method according to claim 33, wherein each of the first processing gas and the second processing gas has intermediate properties between mist liquid phase and vapor phase.

36. The processing method according to claim 33, wherein ultrasonic vibration is applied to a liquid of the first composition to generate nanomist included in the first processing gas and ultrasonic vibration is applied to a liquid of the second composition to generate nanomist included in the second processing gas.

37. The processing method according to claim 33, wherein both the first composition and the second composition are aqueous.

38. The processing method according to Claim 33, wherein the first processing gas and the second processing gas are supplied through a filter so that diameter of nanomist included in the first processing gas and the second processing gas is less than the predetermined value.

39. The processing method according to claim 33, wherein the first processing gas includes plasma-activated nanomist.

40. The processing method according to claim 33, wherein the sample surface is heated so that the substrate surface temperature is higher than a boiling point of each component of the first composition or the second composition, respectively.

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