KR101346897B1 - Etching method and plasma processing system - Google Patents

Abstract

The present invention discloses a method of pretreating the mask layer prior to etching the thin film of the base. Thin films such as dielectric films are etched using plasma supported by ballistic electron beams. To reduce the loss of pattern clarity, such as the Line Edge Roughness (LER) effect, prior to performing the etching process, the oxygen-containing plasma, or halogen-containing plasma, or rare gas plasma, or a combination of two or more thereof. The mask layer is processed.

Description

Etching Method and Plasma Treatment System {ETCHING METHOD AND PLASMA PROCESSING SYSTEM}

The present invention relates to a method of etching a thin film on a substrate in a plasma processing system, and more particularly to a method of treating a mask layer on a thin film before etching the thin film using a plasma supported by a ballistic electron beam.

During semiconductor processing, a (dry) plasma etch process may be utilized to remove or etch the material in patterned vias or contacts on silicon substrates or along fine lines. Plasma etching processes generally involve positioning a semiconductor substrate on which a protective layer, such as a photoresist layer, is patterned within a processing chamber. Once the substrate is positioned in the chamber, the ionizable dissociable gas mixture is introduced into the chamber at a predetermined flow rate while adjusting the vacuum pump to achieve ambient process pressure.

Then, some of the gas species present may be transferred to the heated electrons through inductive or capacitive transfer of high frequency (RF) power, or through the transfer of microwave power using, for example, Electron Cyclotron Resonance (ECR). When ionized by the plasma, a plasma is formed. The heated electrons also serve to dissociate some species of surrounding gas species and produce reactive species suitable for exposed surface etching chemistry. Once the plasma is formed, the selected surface of the substrate is etched by the plasma. This process is adjusted to achieve the proper state, including the appropriate concentration of the desired reactant and ion population, to etch various features (eg, trenches, vias, contacts, etc.) in selected regions of the substrate. Exemplary substrate materials that may require etching include silicon dioxide (SiO ₂ ), low-k materials, polysilicon, and silicon nitride.

It is an object of the present invention to provide an improved method and system for etching a dielectric.

Another object of the present invention is to provide an improved method and system for treating a patterned mask layer to facilitate an etching process.

These and / or other objects of the present invention are achieved by a method of etching a thin film formed on a substrate and having a patterned mask layer thereon. This method comprises the following steps of treating the mask layer by exposing the mask layer to an oxygen containing plasma, a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof, followed by a treating step of treating the mask layer: And etching the thin film to transfer the pattern of the mask layer to the thin film. The etching step includes forming a plasma from the process gas in the plasma processing system and coupling direct current (DC) power to an electrode in the plasma processing system to form an electron beam supporting the plasma during the etching step in the plasma processing system. And exposing the substrate to a plasma and an electron beam.

Another aspect of the invention includes a method of etching a thin film formed on a substrate and having a mask layer patterned thereon. This method includes providing a substrate on a substrate holder in a plasma processing system configured to form a plasma and a ballistic electron beam, and an oxygen-containing plasma, or a halogen-containing plasma, without the mask layer forming a ballistic electron beam. Or, treating the mask layer in the plasma processing system by exposure to the noble gas plasma, or a combination of two or more thereof. The method also includes a forming step that, following the processing step of processing the mask layer, forms a plasma and a ballistic electron beam in the plasma processing system to etch the thin film to transfer the pattern of the patterned mask layer to the thin film.

In another aspect of the invention, a plasma processing system configured to etch a substrate comprises: a processing chamber, a gas supply system configured to supply gas to the processing chamber, a substrate holder coupled to the processing chamber and configured to support the substrate; And an electrode provided inside the processing chamber. An AC power system is coupled to the processing chamber and configured to couple at least one AC signal to the substrate holder or electrode, or both, to form a plasma within the processing chamber, the DC power system is coupled to the processing chamber, and the DC voltage is applied to the electrode. And to form a ballistic electron beam through the plasma. The controller is configured to control the gas supply system, wherein the AC power system and the DC power system have a mask layer, without forming a ballistic electron beam, an oxygen-containing plasma, or a halogen-containing plasma, or a rare gas plasma, or a combination thereof. By exposing to a combination of two or more, the processing step of processing the mask layer in the plasma processing system and the processing step of processing the mask layer, followed by etching the thin film to transfer the pattern of the patterned mask layer onto the thin film. A forming step of forming a plasma and a ballistic electron beam is performed.

1 shows a schematic diagram of a plasma processing system according to an embodiment of the present invention,

2 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

3 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

4 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

5 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

6 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

7 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention,

8 illustrates a method of treating a substrate using plasma in accordance with an embodiment of the present invention.

In the following description, for purposes of explanation without limitation, specific details such as specific geometries and various processes of the plasma processing system are described. However, it should be understood that the invention may be practiced in other embodiments that depart from these specific details.

In a material processing method, pattern etching includes applying a thin layer of photosensitive material, such as photoresist, to a top surface of a substrate, and subsequently patterning the thin layer to form a mask for transferring the pattern to a thin film of the base on the substrate during etching. to provide. In general, the patterning of the photosensitive material includes exposing the photosensitive material by means of a radiation source through a reticle (related optics), for example using a micro-lithography system, followed by photosensitive (as in the case of positive photoresist) The irradiated area of the material is removed, or the non-irradiated area (as in the case of negative resist) is removed using a developing solvent. In addition, the mask layer may include a plurality of sublayers. For example, the mask layer may include a layer of photosensitive material, such as a photoresist, and an anti-reflective coating (ARC) layer of the base.

During pattern etching, mainly a dry plasma etching process is used, in which electromagnetic (EM), such as high frequency (RF) power, is used to heat the electrons and induce subsequent ionization and dissociation of the atomic and / or molecular composition of the process gas. Plasma is formed from the process gas by combining energy with the process gas. In addition, negative high voltage direct current (DC) power may be coupled to the plasma processing system to generate an active (ballistic) electron beam that strikes the substrate surface during a portion of the RF cycle, i.e., one-half cycle of the combined RF power. Can be. The ballistic electron beam improves the characteristics of the dry plasma etching process by, for example, improving the etch selectivity between the thin film of the (etched) base and the mask layer, thereby charging by charging such as electron shading damage and the like. It is observed that the damage can be reduced. It is believed that the dry plasma etching process is enhanced due to the ballistic electrons to modify the mask layer, for example, the resistance to the etching process is enhanced, and the etching selectivity is improved. Further details regarding the generation of ballistic electron beams are disclosed in pending US patent application Ser. No. 11 / 156,559, entitled "Plasma processing apparatus and method," and US Patent Application Publication No. 2006 / 0037701A1, The entire contents of this patent application are incorporated herein by reference.

Referring now to FIG. 1, a schematic diagram of a plasma processing system employing a ballistic electron beam is shown. The plasma processing system includes a first electrode 120 and a second electrode 172 disposed opposite each other in the processing chamber, and the first electrode 120 is configured to support the substrate 125. The first electrode 120 is coupled to a first RF generator 140 configured to provide RF power of the first RF frequency, and the second electrode 172 may be the same as or different from the first RF frequency. Coupled to a second RF generator 170 configured to provide RF power at a second RF frequency. For example, the second RF frequency may be a RF frequency that is relatively higher than the first RF frequency. By coupling RF power to the first and second electrodes, generation of the plasma 130 is facilitated.

The plasma processing system also includes a DC power supply 150 configured to supply a DC voltage to the second electrode 172. By coupling (eg) a negative DC voltage to the second electrode 172, generation of the ballistic electron beam 135 is facilitated. The electron beam power is derived from the superposition of the negative DC voltage on the second electrode 172. As disclosed in US Patent Application Publication 2006 / 0037701A1, applying negative DC power to a plasma processing system affects the formation of a ballistic (or non-collision) electron beam that strikes the surface of the substrate 125.

In general, ballistic electron beams can be realized with any type of plasma processing system, as described below. In this example, negative DC voltages are superimposed on an RF power capacitively coupled plasma (CCP) processing system. Therefore, the present invention is not limited to this example. This example is for illustrative purposes only.

Although ballistic electron beams are important in improving the etching properties, the inventors of the present invention have found that in many cases, ballistic electron beams can lead to scratched or abnormal patterns (mainly " line edge roughness (LER) "). Was observed to develop in the mask layer. In particular, the inventors of the present application find that LER occurs most frequently in etching chemicals (eg, CF ₄ chemicals) that form relatively low polymers (eg, relatively low CF ₂ radical content), and form relatively many polymers. It has been observed that LER does not occur very much in etching chemicals (eg, C ₄ F ₈ or C ₅ F ₈ chemicals) of relatively high CF ₂ radical content. Such abnormal patterns and sidewall roughness may be transferred to the layer of the base during the current etching process and / or subsequent etching processes. For example, when the substrate is first exposed to an etching process with a bond-breaking excitation, such as a ballistic electron beam assisted plasma, the mask layer is modified to show sidewall roughness (or abnormal patterns) in the pattern formed on the mask layer. Such sidewall roughness may be transferred to the etching film as the etching process proceeds. This may lead to a decrease in manufacturing yield and / or a decrease in device performance and reliability.

The inventors of the present application studied the properties of ballistic electron beam assisted plasma in an effort to identify the cause of the aforementioned LER problem. The inventors of the present application have found that long-term exposure of a mask layer, such as a photoresist layer, to an active electron beam (e.g., electron energy above about 100 eV) may modify the mask layer to improve the etching process as described above. It is believed that the initial exposure to the beam can result in damage, including electron induced defects, which may result in the formation of a scratch (referred to as LER) in the mask layer when atomic halogen species are present. For example, when the mask layer is exposed to the above-described fluorine-containing etching chemical, due to the cleavage of chemical bonds in the surface layer of the mask layer, fluorine oxidation (by atomic fluorine) and the energy of incident electrons (from the surface of the mask layer) To a depth determined by < RTI ID = 0.0 >). ≪ / RTI > In general, the inventors of the present application, in the conventional ballistic electron beam etching process, the subsequent exposure of the mask layer to atomic halogen species in the presence of the ballistic electron beam may be advantageous for the etching process, but the presence of the ballistic electron beam It is believed that initial exposure of the mask layer to atomic halogen species in the state can result in LER.

Accordingly, the inventors of the present application expect that treating the mask layer prior to performing the etching process can reduce the development of LER during the etching process. The mask layer may comprise a silicon containing layer or may comprise a silicon free layer. The mask layer may also include a photosensitive material such as a photoresist. For example, the mask layer may comprise a 248 nanometer (nm) photoresist, a 193 nm photoresist, a 157 nm photoresist, or an extreme ultraviolet (EUV) photoresist, or a combination of two or more thereof.

According to one embodiment, prior to performing the etching process of transferring the pattern formed on the mask layer to the base thin film, the patterned mask layer is subjected to oxygen-containing plasma, halogen-containing plasma, or rare gas plasma, or two or more thereof. Expose to combination. The mask layer is treated by an oxygen-containing plasma, or a halogen-containing plasma, or a rare gas plasma, or a combination of two or more thereof in the absence of bond breaking excitation, such as active electrons and active photons. Preferably, the treatment plasma is a plasma in which active ions (ie, low energy ions on the substrate) hardly or never collide with the patterned mask. Accordingly, the high frequency (RF) or microwave power supplied to the plasma source is preferably provided at a power level sufficient to dissociate and ionize the oxygen or halogen gas and to ionize the rare gas. In one embodiment, the power supplied to the plasma source is about 2000 W or less. Preferably, the power supplied to the plasma source is about 500 W or less. In addition, the bias power supplied to the substrate electrode is less than about 500 W, preferably less than about 100 W. More preferably, the bias power is power such that substantially no power is applied to the substrate electrode. In addition, the plasma treatment is performed for about 1 second to 30 seconds, preferably about 2 to 20 seconds, such as about 10 seconds.

The mask layer may be exposed in a plasma processing system used for the etching process, such as the plasma processing system shown in FIG. 1, or the mask layer may be exposed in a substrate processing system other than the plasma processing system for performing the etching process. It may be. Plasma can be generated on-site using a plasma generation system that facilitates the generation of plasma during the etching process, or using a remote plasma generation system in which the etching process is coupled to a plasma processing system or a separate substrate processing system performed in-house. To generate a plasma at a remote location.

The oxygen containing plasma may be formed of O ₂ , CO, CO ₂ , NO, N ₂ O, or NO ₂ , or a combination of two or more thereof. The flow rate of the oxygen containing gas may be from about 10 sccm (standard cubic centimeters per minute) to about 1000 sccm, such as 100 sccm to 300 sccm. The chamber pressure may be about 1 mTorr to about 1000 mTorr, preferably about 50 mTorr to about 500 mTorr, more preferably about 100 mTorr to about 500 mTorr. The oxygen containing plasma may further comprise an inert gas, rare gas, N ₂ , H ₂ or CN. The inventors of the present application believe that the use of an oxygen-containing plasma can promote the formation of a sublayer in a mask layer in which the concentration of oxygen is increased. The inventors of the present application expect that the mask layer thus treated will help to reduce the LER in the mask layer in subsequent etching processes. For example, in the case of a silicon-containing mask layer, a "glassy" (ie SiO _x ) sublayer can be formed, which is expected to be particularly elastic in the formation of the LER.

As an example, the mask layer is treated with an oxygen-containing plasma in a plasma processing system in which an etching step is performed inside. Process conditions include a flow rate of an oxygen containing gas of about 100 sccm to about 500 sccm; Chamber pressure of at least about 100 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 500 W; The processing time is about 10 seconds. As another example, using a remote (remote) plasma source such as a microwave power plasma source, the mask layer is processed by an oxygen-containing plasma. Process conditions include a flow rate of an oxygen containing gas of about 100 sccm to about 500 sccm; Chamber pressure of at least about 100 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); Microwave power of about 1000 W; Then, the processing time is about 10 seconds.

The halogen containing plasma may be formed of Cl ₂ , Br ₂ , F ₂ , HBr, HCl, HF, C ₂ H ₄ Br ₂ , ClF ₃ , NF ₃ , SiCl ₄ or SF ₆ , or a combination of two or more thereof. The flow rate of the halogen containing gas may be about 10 sccm to about 1000 sccm, such as about 100 sccm to 300 sccm. The chamber pressure may be about 1 mTorr to about 1000 mTorr, preferably about 20 mTorr to about 500 mTorr, more preferably about 20 mTorr to about 100 mTorr. The halogen containing plasma may further comprise an inert gas, rare gas, N ₂ , H ₂ , or CN. In addition, the halogen-containing plasma may further include an oxygen-containing gas. The inventors expect that exposing the mask layer to a halogen-containing plasma in the absence of an active electron beam will passivate the surface layer of the mask layer, thereby helping to reduce the LER in the mask layer in subsequent etching processes. Doing.

As an example, the mask layer is treated with a halogen-containing plasma in a plasma processing system in which an etching process is performed inside. Process conditions include a flow rate of halogen containing gas from about 100 sccm to about 500 sccm; A chamber pressure of about 25 mTorr to about 50 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 100 W to about 500 W; The processing time is about 10 seconds. As another example, processing of the mask layer by halogen-containing plasma is performed using a remote (remote) plasma source such as a microwave power plasma source. Process conditions include a flow rate of halogen containing gas from about 100 sccm to about 500 sccm; Chamber pressure of at least about 100 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); Microwave power of about 1000 W; The processing time is about 10 seconds.

The rare gas plasma may be formed of a rare gas such as He, Ne, Ar, Xe, Kr or a combination of two or more thereof. The flow rate of the rare gas may be about 10 sccm to about 1000 sccm, such as about 100 sccm to 300 sccm. The chamber pressure may be about 1 mTorr to about 1000 mTorr, preferably about 50 mTorr to about 500 mTorr, more preferably about 50 mTorr to about 200 mTorr. The inventors believe that using a rare gas plasma can facilitate the formation of carbon rich, or “carbonized” (ie, lacking O and H) surface layers on the mask layer. The “carbonized” surface layer can extend several nanometers (nm) (eg, 1 nm to 10 nm) into the mask layer, depending on the ion energy of the ions striking the mask layer. For example, ions having an energy ranging from about 25 eV to about 50 eV penetrate from about 1 nm to about 2 nm. The inventors of the present application expect that this treated mask layer will help to reduce the LER in the mask layer in a subsequent etching process.

As an example, the mask layer is processed by the rare gas plasma in the plasma processing system in which the etching step is performed. Process conditions include a flow rate of rare gas of about 100 sccm to about 300 sccm; A chamber pressure of about 25 mTorr to about 50 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 500 W to about 1000 W; The processing time is about 10 seconds.

According to another embodiment, a protective layer is formed on the mask layer before performing an etching process for transferring the pattern formed on the mask layer to the thin film of the base. The protective layer formed on the mask layer may include a layer of material consumed or partially consumed during the etching process, thereby protecting the mask layer during the initial stages of the etching process. Alternatively, the protective layer formed on the mask layer can increase the etch resistance during the etching process, in particular during the initial stage of the etching process.

In a plasma processing system in which an etching process is performed inside, such as the plasma processing system shown in FIG. 1, a protective layer may be formed on the mask layer, or in a substrate processing system other than the plasma processing system in which the etching process is performed in-house. You can perform the exposure. Plasma can be generated on-site using a plasma generation system that facilitates the generation of plasma during the etching process, or using a remote plasma generation system in which the etching process is coupled to a plasma processing system or a separate substrate processing system performed in-house. To generate a plasma at a remote location.

When the protective layer is formed on the mask layer, the deposition gas plasma is utilized, and if the mask layer is exposed to the deposition gas plasma at this time, net deposition of material occurs on the substrate surface. To form a protective layer on the mask layer, a hydrocarbon-containing plasma (ie, a C _x H _y- containing plasma, where x and y represent an integer of 1 or more), or a fluorocarbon-containing plasma (C _x F _z- containing plasma) , Wherein x and z represent an integer of 1 or more), or a hydrofluorocarbon containing plasma (C _x H _y F _z containing plasma, where x, y and z represent an integer of 1 or more), or two or more thereof Exposing the mask layer to a deposition gas plasma, such as a combination. The mask layer is treated by the deposition gas plasma in the absence of bond breaking excitation such as active electrons or active photons. C _x H _y -containing plasma is C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ , or C ₆ H ₁₂ , or a combination of two or more thereof. The C _x F _z containing plasma may be formed using C ₂ F ₆ , CF ₄ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , or C ₄ F ₆ , or a combination of two or more thereof. . The C _x H _y F _z containing plasma may be formed using CH ₃ F, C ₂ HF ₅ , CH ₂ F ₂ , or CHF ₃ , or a combination of two or more thereof.

Process conditions are selected to form a protective layer of hydrocarbon, fluorocarbon, or a combination thereof on the mask layer using one or more of the foregoing deposition gases. Process conditions should be chosen so that the pattern formed on the mask layer is not isolated or tapered. The protective layer may cover a flat-field. In addition, the protective layer may include some overhang on the pattern, and may further include some coverage of the sidewalls of the pattern in the mask layer. For example, process conditions may be used to form an ion-driven depositing plasma (i.e., deposition of ionized species) using driving forces by ions with little or no sputtering (i.e., low ionic energy at the substrate surface). Should be chosen. The flow rate of the deposition gas may be about 10 sccm to about 1000 sccm, preferably about 100 sccm to about 300 sccm, such as about 200 sccm. The chamber pressure may be about 1 mTorr to about 1000 mTorr, preferably about 50 mTorr to about 500 mTorr, more preferably about 50 mTorr to about 200 mTorr. In addition, the deposition gas plasma may further include a diluent gas, such as a rare gas. For example, the flow rate of the deposition gas may range from about 1% to about 20% of the gas mixture, with the remainder occupied by the flow rate of the diluent gas. Also, for example, the flow rate of the deposition gas may range from about 5% to about 10% of the gas mixture, with the remainder occupied by the flow rate of the diluent gas. In addition, the deposition gas may also include H ₂ , O ₂ , CO, CO ₂ , NO, N ₂ O, NO ₂ , N ₂ , CN, or an inert gas, or a combination of two or more thereof.

As one example, when depositing the CF (i.e., C _x F _z) polymer, without with CF ₄ or CF _4, it is possible to use a deposition gas, such as C ₄ F ₈ or C ₄ F _6. Process conditions include flow rates of diluent gas from about 100 sccm to about 500 sccm; A flow rate of the deposition gas from about 1% to about 20% of the flow rate of the dilution gas; A chamber pressure of about 50 mTorr to about 200 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 500 W to about 1500 W; And a processing time sufficient to form a film having a thickness in the range of about several nm to about 200 nm.

As another example, when depositing a CH (ie, C _x H _y ) polymer, process conditions include: a flow rate of diluent gas of about 100 sccm to about 500 sccm; A flow rate of the deposition gas from about 1% to about 20% of the flow rate of the dilution gas; A chamber pressure of about 50 mTorr to about 200 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 500 W to about 1500 W; And a processing time sufficient to form a film having a thickness in the range of about several nm to about 200 nm.

The inventors of the present application believe that the CF film can provide a relatively large etching resistance during the etching process, so that the required thickness of the protective layer for the CH film may be larger than the required thickness of the protective layer for the CF film. The minimum thickness of the protective layer should be selected according to the penetration depth of the charged species during the etching process. For example, a film about 50 nm thick may be needed for a 1 keV electron beam, and a film about 100 nm thick may be needed for a 1.5 keV electron beam.

As another example, forming the protective layer on the mask layer may include immersing the mask layer in alcohol such as methanol or ethanol.

The inventors of the present application, when forming a protective layer on the mask layer using a hydrocarbon-based chemical or a hydrofluorocarbon-based chemical, the content of hydrogen increases on the surface of the mask layer, thereby acting during the initial stage of the etching process. It is expected to weaken the former electron. By mitigating the damaging effects of active electron beams during these early stages of the etching process, the sacrificial layer can help reduce the LER in the mask layer in subsequent etching processes. In addition, the inventors have found that forming a protective film on a mask layer using a hydrofluorocarbon-based chemical or a fluorocarbon-based chemical provides the formation of a polymer film that provides additional etching resistance to the mask layer during the etching process. I hope to facilitate this. Improving the etching selectivity with respect to the modified mask layer can help reduce the LER in the mask layer after the etching process.

According to another embodiment, the mask layer is treated with an electron beam in the absence of atomic halogen species (ie, F, Cl, Br, etc.) prior to performing the etching process. The inventors of the present application, exposing the mask layer to an electron beam in the absence of atomic halogen species make the surface layer of the mask layer "cure" or hard, making the mask layer less sensitive to the formation of LER during the etching process. .

The exposure process of exposing the mask layer to the electron beam may be performed in a plasma processing system in which an etching process is performed inside, such as the plasma processing system shown in FIG. 1, and such exposure process may be performed in a plasma process in which the etching process is performed inside. It may be executed in a substrate processing system other than the system. For example, an electron beam source can be coupled to a plasma processing system (for an etching process) or other substrate processing system and can be configured to generate an electron beam for processing a mask layer.

Alternatively, electron beams may be generated within the plasma processing system, for example, by forming a plasma by combining direct current (DC) power to an electrode in the plasma processing system (as described in FIGS. 1 and 2 to 7 below). Can be. Referring to FIG. 1, the plasma for pre-etching may be formed by combining alternating current (AC) power, such as high frequency (RF) power, with the first electrode 120, the second electrode 172, or both. By coupling the DC power to the second electrode 172, an electron beam for preetching may be formed.

The pre-etched electron beam may be used to treat the surface layer of the mask layer prior to the etching process. The treatment depth may be about 1 nm to about 100 nm, preferably about 5 nm to about 50 nm, such as 10 nm. These penetration ranges are obtainable using electron beam energy in the range of about 500 eV to about 1.5 keV. The electron beam energy for pre-etching can reach about 1.5 keV and preferably range from about 200 eV to about 1.5 keV, such as 500 eV. The exposure to the pre-etched electron beam may be selected to produce a dose in the range of about 10 ¹⁴ electrons / cm 2 to about 10 ¹⁶ electrons / cm 2.

As an example, an electron beam for pre-etching is formed in the plasma processing system of FIG. Process conditions include a flow rate of rare gas of about 100 sccm to about 300 sccm; A chamber pressure of about 20 mTorr to about 100 mTorr; Little or no RF bias power is supplied to the bottom electrode (on which the substrate is placed); RF power supplied to the upper electrode (or induction coil) is about 500 W to about 1000 W; A DC voltage supplied to the upper electrode is about -500 V to about -1000 V; The processing time is about 10 seconds.

An inert gas such as a rare gas (eg, He, Ne, Ar, Xe, Kr) may be used to form a plasma for pre-etching. In addition, the plasma for pre-etching may further include CHF ₃ . In the presence of plasma, dissociation of CHF ₃ tends to produce a population of CF ₂ (eg, polymer forming radicals) and (ion bonded) HF. The polymer forming radical may be advantageous for the treatment of the mask layer by providing a sacrificial layer as described above. However, it is important to select an additive gas (added to the inert plasma forming gas) such that atomic halogen species are not present in the presence of the plasma in order to treat the mask layer while reducing the LER problem described above.

The mask layer may be treated by a pre-etch electron beam and a pre-etch plasma for a predetermined time period, such as about 10 seconds. Further, the treatment with the electron beam for preetching is performed for about 1 second to 30 seconds, preferably about 2 seconds to 20 seconds, such as about 10 seconds. After such treatment, the etching gas can be formed using the etching gas, the etching electron beam can be formed, and the etching process is performed by exposing the substrate having the treated mask layer to the etching electron beam and the etching plasma. You can proceed. The electron beam energy for pre-etching may be selected approximately equal to the electron beam energy for etching, and alternatively, the electron beam energy for pre-etching may be selected smaller than the electron beam energy for etching. For example, the electron beam energy for pre-etching may be about 500 eV, while the electron beam energy for etching may be about 1500 eV. The electron beam energy (or the voltage applied to the second electrode 172 of FIG. 1) may increase step by step during the preetch process, and the electron beam energy may have a slope during the preetch process. In addition, the electron beam energy (or the voltage applied to the second electrode 172 of FIG. 1) may be in the form of a pulse. For example, the voltage applied to the second electrode 172 is between about 0 V and about -1500 V, preferably between about -100 V and about -1500 V, more preferably between about -500 V and about- It may be in the form of a pulse between 1500 V.

 Prior to the treatment of the mask layer using an oxygen-containing plasma, a halogen-containing plasma, or a rare gas plasma, the mask layer may be treated with an electron beam for preetching. Further, prior to forming the protective layer on the mask layer, the mask layer may be treated with an electron beam for preetching. For example, the electron beam for preetching may prepare the surface of a mask layer for polymer growth during formation of a protective layer.

These embodiments may be implemented with any type of plasma processing system, as shown below.

Referring now to FIG. 2, shown is a plasma processing system according to one embodiment, configured to process a mask layer prior to etching the layer of the base using plasma enhanced by a ballistic electron beam. The plasma processing system 1 includes a plasma processing chamber 8 configured to facilitate the formation of a plasma, a substrate holder 2 coupled to the plasma processing chamber 8 and configured to support the substrate 3, and a plasma processing chamber. An electrode 9 coupled to 8 and configured to be in contact with the plasma. In addition, the plasma processing system 1 is AC power coupled to the plasma processing chamber 8 and configured to couple at least one AC signal to the substrate holder 2, the electrode 9, or both to form a plasma. A system 4 and a DC power system 5 coupled to the plasma processing chamber 8 and configured to couple a DC voltage to the electrode 9 to form a ballistic electron beam through the plasma.

The plasma processing system 1 also includes a process gas distribution system 6 coupled to the plasma processing chamber 8 and configured to introduce any of the gases described in the foregoing embodiments. The plasma processing system 1 also includes a vacuum pumping system (not shown) coupled to the plasma processing chamber 8 and configured to exhaust gas from the plasma processing chamber.

Optionally, the plasma processing system 1 includes a controller coupled to the plasma processing chamber 8, the substrate holder 2, the AC power system 4, the DC power system 5, and the process gas distribution system 6. 7), wherein the controller is configured to exchange data with each of the above components to execute a process of processing the substrate 3 in the plasma processing chamber 8. The plasma processing system 1 can facilitate the treatment of the mask layer on the substrate 3, the etching process of the substrate 3, or both.

3 illustrates a plasma processing system according to another embodiment. The plasma processing system 1a includes a plasma processing chamber 10, a substrate holder 20 to which a substrate 25 to be processed is attached, and a vacuum pumping system 30. The substrate 25 may be a semiconductor substrate, a wafer, or a liquid crystal display. The plasma processing chamber 10 may be configured to facilitate the generation of plasma in the processing region 15 adjacent to the surface of the substrate 25. An ionizable gas or mixture of gases is introduced via a gas injection system (not shown) and the process pressure is adjusted. For example, a control mechanism (not shown) can be used to adjust the vacuum pumping system 30. The plasma may be utilized to form a particular material for a particular material process and / or assist in removing material from the exposed surface of the substrate 25. The plasma processing system 1a may be configured to process substrates of any size, such as 200 mm substrates, 300 mm substrates, or larger substrates.

Substrate 25 may be attached to substrate holder 20 via an electrostatic clamping system. The substrate holder 20 also receives heat from the substrate holder 20 upon cooling, transfers the heat to a heat exchanger system (not shown), and, upon heating, flows heat from the heat exchanger into the fluid flow. It may further comprise a cooling system or a heating system having a recirculating fluid flow to deliver to. In addition, gas may be supplied to the back side of the substrate 25 through the back side gas system to improve the gas-gap thermal conductivity between the substrate 25 and the substrate holder 20. Such systems can be used when temperature control of the substrate is required at elevated or lowered temperatures. For example, the backside gas system may comprise a two-zone gas distribution system wherein the pressure of the backside gas (eg, helium) may be changed independently between the center and the edge of the substrate 25. have. In another embodiment, a heating / cooling element, such as a resistive heating element, or a thermoelectric heater / cooler, may be applied to the substrate holder 20 as well as to any other components in the plasma processing system 1a and the chamber walls of the plasma processing chamber 10. ) Can be provided.

In the embodiment shown in FIG. 3, substrate holder 20 may include an electrode that couples RF power to a processing plasma in processing space 15. For example, the substrate holder 20 may be electrically biased with the RF voltage by transferring RF power from the RF generator 40 to the substrate holder 20 via an optional impedance match network 42. RF bias can perform the action of heating electrons to generate and maintain a plasma, or affect the ion energy distribution function in the sheath, or both. In this structure, the system can act as a reactive ion etching (RIE) reactor, where the chamber can act as a ground plane. Typical frequencies for the RF bias can range from 0.1 MHz to 100 MHz. RF systems for plasma processing are well known to those skilled in the art.

In addition, the amplitude of the RF power coupled to the substrate holder 20 may be modulated to affect a change in the spatial distribution of the electron beam flux with respect to the substrate 25. Further details are disclosed in co-pending US patent application Ser. No. 11 / XXX, XXX, filed Jul. 31, 2006 and entitled "Method and system for controlling the uniformity of a ballistic electron beam by RF modulation". And the entire contents of this patent application are incorporated herein by reference in their entirety.

In addition, the impedance match network 42 serves to improve the transfer of RF power to the plasma in the plasma processing chamber 10 by reducing the reflected power. Match network topologies (eg, L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

Still referring to FIG. 3, the plasma processing system 1a further includes a direct current (DC) power supply 50 coupled to the upper electrode 52 opposite the substrate 25. The upper electrode may comprise an electrode plate. The electrode plate may comprise a silicon-containing electrode plate. In addition, the electrode plate may include a doped silicon electrode plate. The DC power supply may include a variable DC power supply. In addition, the DC power supply may comprise a bipolar DC power supply. The DC power supply 50 may further include a system configured to perform at least one of the function of monitoring, adjusting, or controlling the polarity, current, voltage, or on / off state of the DC power supply 50. have. Once the plasma is formed, the DC power supply 50 facilitates the formation of a ballistic electron beam. An electrical filter may be utilized to decouple the RF power from the DC power supply 50.

For example, the DC voltage applied to the electrode 52 by the DC power supply 50 may range from about -2000 volts (V) to about 1000 volts. Preferably, the absolute value of the DC voltage has a value of about 100 V or more, and more preferably the absolute value of the DC voltage has a value of about 500 V or more. It is also desirable that the DC voltage has a negative polarity. In addition, the DC voltage is preferably a negative voltage having an absolute value higher than the self-bias voltage generated on the surface of the upper electrode 52. The surface of the upper electrode 52 facing the substrate holder 20 may be made of a silicon containing material.

The vacuum pumping system 30 may include a Turbo Molecular vacuum Pump (TMP) capable of pumping speeds of up to 5000 liters / second (or more) and a gate valve to regulate chamber pressure. In a conventional plasma processing apparatus used for dry plasma etching, a TMP of 1000 liters / second to 3000 liters / second can be employed. TMP can typically be used for low pressure treatments of less than 50 mTorr. For high pressure treatments (ie greater than 1000 mTorr), mechanical booster pumps and dry roughing pumps can be used. In addition, an apparatus (not shown) for monitoring chamber pressure may be coupled to the plasma processing chamber 10. The pressure measuring device can be, for example, a Type 628B Baratron absolute capacitive manometer available from MKS Instruments, Inc. (Andover, Mass.).

Still referring to FIG. 3, the plasma processing system 1a further includes a controller 90 having a microprocessor, a memory, and a digital I / O port, wherein the digital I / O port is a plasma processing system 1a. In addition to monitoring the output from the plasma processing system 1a, it is possible to generate a control voltage sufficient to actuate an input to the processing system 1a. The controller 90 also includes an RF generator 40, an impedance match network 42, a DC power supply 50, a gas injection system (not shown), a vacuum pumping system 30, and a backside gas delivery system ( Shown), substrate / substrate holder temperature measurement system (not shown), and / or electrostatic clamping system (not shown) to exchange information with them. The program stored in the memory can be used to actuate the inputs to the aforementioned components of the plasma processing system 1a according to the process recipe to perform the method of etching the thin film. An example of the controller 90 is DELL PRECISION WORKSTATION 610 ^™, which is commercially available from DELL Corporation, Austin, Texas.

The controller 90 may be located close to the plasma processing system 1a or may be located remote to the plasma processing system 1a via the Internet or an intranet. Accordingly, the controller 90 may exchange data with the plasma processing system 1a using at least one of a direct connection, an intranet, or the Internet. The controller 90 may be coupled to an intranet of a customer site (ie, a device manufacturer, etc.) or may be coupled to an intranet of a vendor site (ie, an equipment manufacturer). In addition, other computers (ie, controllers, servers, etc.) may access the controller 90 to exchange data over at least one of a direct connection, an intranet, or the Internet.

In the embodiment shown in FIG. 4, the plasma processing system 1b may be similar to the embodiment of FIG. 2 or 3, in order to potentially increase the plasma density and / or improve the plasma processing uniformity. In addition to the components described with reference to FIG. 2, it further includes a fixed, mechanical, or electrical rotating magnetic field system 60. The controller 90 can also be coupled to the magnetic field system 60 to adjust the rotational speed and the magnetic field strength. Design and implementation of rotating magnetic field systems are well known to those skilled in the art.

In the embodiment shown in FIG. 5, the plasma processing system 1c may be similar to the embodiment of FIG. 2 or 3, coupling RF power to the upper electrode 52 through an optional impedance match network 72. It may further comprise an RF generator 70 configured to.

Typical frequencies for applying RF power to the upper electrode 52 may range from about 0.1 MHz to about 200 MHz. Also, a typical frequency for applying power to the substrate holder 20 (or lower electrode) may range from about 0.1 MHz to about 100 MHz. For example, the RF frequency coupled to the upper electrode 52 may be relatively higher than the RF frequency coupled to the substrate holder 20. Also, the RF power from the RF generator 70 to the upper electrode 52 may be amplitude modulated, the RF power from the RF generator 40 to the substrate holder 20 may be amplitude modulated, and both RF powers are amplitude modulated. It may be modulated. Preferably, the RF power of the higher RF frequency is amplitude modulated. The controller 90 is also coupled to the RF generator 70 and the impedance match network 72 to control the application of RF power to the upper electrode 52. The design and implementation of the upper electrode is well known to those skilled in the art.

Still referring to FIG. 5, the DC power supply 50 may be coupled directly to the upper electrode 52, or may be coupled to an RF transmission line extending from the output end of the impedance match network 72 to the upper electrode 52. have. An electrical filter may be utilized to decouple the RF power from the DC power supply 50.

In the embodiment shown in FIG. 6, the plasma processing system 1d may be similar to the embodiment of FIGS. 2, 3, and 4, for example, and may be connected from the RF generator 82 via an optional impedance match network 84. It may further include an induction coil 80 to which the RF power is coupled. RF power is inductively coupled from the induction coil 80 to the plasma processing region 15 through an insulator window (not shown). Typical frequencies for applying RF power to induction coil 80 may range from about 10 MHz to about 100 MHz. Likewise, typical frequencies for applying power to the substrate holder 20 (or lower electrode) may range from about 0.1 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) may be employed to reduce capacitive coupling between the induction coil 80 and the plasma. The controller 90 is also coupled to the RF generator 82 and the impedance match network 84 to control the application of power to the induction coil 80. In a variant, the induction coil 80 may be a "spiral" coil or a "pancake" coil that communicates with the plasma processing region 15 from above, such as in a Transformer Coupled Plasma (TCP) reactor. The design and implementation of an Inductively Coupled Plasma (ICP) source or TCP source is well known to those skilled in the art.

Alternatively, plasma may be formed using Electron Cyclotron Resonance (ECR). In another embodiment, a plasma is formed from launching the helicon wave. In yet another embodiment, a plasma is formed from the transfer surface wave. Each plasma source described above is well known to those skilled in the art.

In the embodiment shown in FIG. 7, the plasma processing system 1e may be similar to the embodiment of FIGS. 3, 4 and 5, for example, and may be connected to the substrate holder 20 via another optional impedance match network 46. It may further comprise a second RF generator 44 configured to couple the RF power. Typical frequencies for applying RF power to the substrate holder 20 may range from about 0.1 MHz to about 200 MHz for the first RF generator 40, the second RF generator 44, or both. have. The RF frequency of the second RF generator 44 may be relatively higher than the RF frequency of the first RF generator 40. In addition, the RF power from the first RF generator 40 to the substrate holder 20 may be amplitude modulated, and the RF power from the second RF generator 44 to the substrate holder 20 may be amplitude modulated, both of which are The RF power of may be amplitude modulated. Preferably the RF power of the higher RF frequency is amplitude modulated. The controller 90 is also coupled to the second RF generator 44 and the impedance match network 46 to control the application of RF power to the substrate holder 20. Design and implementation of RF systems for substrate holders are well known to those skilled in the art.

In the following description, a method of etching a thin film using a plasma processing system employing a ballistic electron beam is presented. For example, the plasma processing system may include various elements as described in FIGS. 1-7 and combinations thereof.

8 shows a flowchart of a thin film etching method according to an embodiment of the present invention. Process 500 begins at processing step 510 where the pattern is formed and the mask layer covering the thin film on the substrate is processed.

The mask layer can be processed using any of the embodiments described above. For example, the step of treating the mask layer may include exposing the mask layer to an oxygen containing plasma or a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof. Alternatively, processing the mask layer may include forming a protective layer on the mask layer. Alternatively, the processing of the mask layer may include exposing the mask layer to an electron beam in the absence of atomic halogen species. Alternatively, the processing step of the mask layer may include any combination of the aforementioned processes.

In step 520 , the mask layer-treated substrate is exposed to a dry etch plasma supported by an active (ballistic) electron beam, thereby reducing the abnormal pattern such as LER, while transferring the pattern formed on the mask layer to the base film. do. In the plasma processing system, (process) plasma is formed from the process gas by causing power to be coupled to the process gas (which causes ionization and dissociation of the process gas molecules). By coupling the DC power to the electrode in the plasma processing system and forming the plasma, an active (ballistic) electron beam having an energy level that depends on the magnitude of the DC voltage applied to the electrode is produced.

DC power is coupled to the plasma processing system. For example, the DC voltage applied to the plasma processing system by the DC power supply may range from about -2000 volts (V) to about 1000 volts. Preferably, the absolute value of the DC voltage has a value of about 100 V or more, and more preferably the absolute value of the DC voltage has a value of about 500 V or more. In addition, the DC voltage preferably has a negative polarity. In addition, the DC voltage is preferably a negative voltage having an absolute value greater than the self bias voltage generated at the electrode surface of the plasma processing system.

While only specific exemplary embodiments of the invention have been described in detail, those skilled in the art can readily appreciate that many modifications can be made to the embodiments without substantially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.

Claims (67)

An etching method for etching a thin film formed on a substrate and patterned with a mask layer thereon, Treating the mask layer by exposing the mask layer to an oxygen-containing plasma, a halogen-containing plasma, or a rare gas plasma, or a combination of two or more thereof; A processing step of processing the mask layer, followed by an etching step of etching the thin film to transfer the pattern of the mask layer to the thin film, The etching step, A forming step of forming a plasma in the plasma processing system from the process gas; Coupling a direct current (DC) power to an electrode in the plasma processing system to form an electron beam supporting the plasma in the plasma processing system during the etching step; And exposing the substrate to the plasma and the electron beam. The mask layer of claim 1, wherein the processing of the mask layer comprises: forming the mask layer in a plasma formed using O ₂ , CO, CO ₂ , NO, N ₂ O, or NO ₂ , or a combination of two or more thereof. Etching step of exposing the light. The method of claim 2, wherein the treating step further comprises exposing the mask layer to N ₂ , H ₂ , CN, inert gas, or a combination of two or more thereof. 3. The method of claim 2, wherein said treating step further comprises exposing said mask layer to a halogen containing gas. The method of claim 1, wherein the treating step of treating the mask layer comprises Cl ₂ , Br ₂ , F ₂ , HBr, HCl, HF, C ₂ H ₄ Br ₂ , SiCl ₄ , NF ₃ , SF ₆ , or these And exposing the mask layer to a plasma formed using a combination of two or more of the following. The method of claim 5, wherein the treating step further comprises exposing the mask layer to N ₂ , H ₂ , CN, rare gas, or a combination of two or more thereof. 6. The method of claim 5, wherein said treating step further comprises exposing said mask layer to an oxygen containing gas. The plasma processing system of claim 1, wherein the processing step of processing the mask layer is performed by coupling AC power to the electrode or another electrode other than the electrode, or a substrate holder, a combination of two or more thereof. And exposing the mask layer. 9. The method of claim 8, wherein said processing step of processing said mask layer comprises exposing said mask layer to a low power plasma formed using a power level of 500 W or less. The method of claim 1, wherein the processing step comprises exposing the mask layer to a plasma formed in a remote plasma source coupled to the plasma processing system. 2. The method of claim 1, wherein said combining step of combining DC power comprises combining a DC power in a voltage range of -2000 V to 1000 V. 2. The method of claim 1, wherein said combining step of combining DC power comprises combining DC power having a negative polarity, wherein an absolute value of the DC power is at least 500V. The etching method according to claim 1, wherein the coupling step of coupling the DC power to the electrode comprises coupling the DC power to an upper electrode opposite to the substrate installed in the substrate holder. The method of claim 13, wherein the forming of the plasma comprises coupling a high frequency (RF) power to the electrode or another electrode other than the electrode, or a substrate holder, a combination of two or more thereof. Etching method. 15. The method of claim 14, wherein the combining step of combining the RF power comprises: coupling a first RF power of a first RF frequency to the upper electrode and applying a second RF power of a second RF frequency that is less than the first RF frequency. And a bonding step of coupling to the substrate holder. The method of claim 14, And a modulating step of modulating the amplitude of the RF power to adjust the spatial distribution of the electron beam flux relative to the electron beam. The method of claim 1, wherein exposing the mask layer to the oxygen containing plasma or the halogen containing plasma prior to the etching step reduces line edge roughness (LER) formed in the mask layer during the etching step. Etching method. The method of claim 1, wherein the processing step is performed for a predetermined time period so that the patterned mask layer has resistance to LER formed in the mask layer during the etching step. The method of claim 1, wherein the processing of the mask layer comprises exposing the mask layer to a plasma formed using He, Ne, Ar, Xe, Kr or a combination of two or more thereof. Phosphorus etching method. The method of claim 1, Prior to the processing step of treating the mask layer by exposing the mask layer to an oxygen containing plasma, or a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof, a state without atomic halogen species to modify the mask layer. And a pretreatment step of pretreating the mask layer with a pre-etched electron beam. The method of claim 1, wherein the processing step of treating the mask layer by exposing the mask layer to an oxygen containing plasma, a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof, comprises: a first of a first RF frequency; Coupling RF power to an upper electrode and coupling a second RF power of a second RF frequency less than the first RF frequency to a substrate holder, wherein the second RF power is 100 W or less. Way. The method of claim 21, wherein the second RF power is zero. An etching method for etching a thin film formed on a substrate and patterned with a mask layer thereon, Providing a substrate on a substrate holder in a plasma processing system configured to form a plasma and a ballistic electron beam; Treating the mask layer in the plasma processing system by exposing the mask layer to an oxygen containing plasma, a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof, without forming a ballistic electron beam. Processing steps, Subsequent to the processing step of processing the mask layer, forming a plasma and a ballistic electron beam in the plasma processing system to etch the thin film and transfer the pattern of the patterned mask layer to the thin film. Etching method comprising a. A plasma processing system configured to etch a thin film formed on a substrate and having a mask layer patterned thereon, the method comprising: A processing chamber, A gas supply system configured to supply gas to the processing chamber; A substrate holder coupled to the processing chamber and configured to support the substrate; An electrode provided inside the processing chamber; An AC power system coupled to the processing chamber and configured to couple at least one AC signal to the substrate holder or the electrode, or both, to form a plasma within the processing chamber; A DC power system coupled to the processing chamber and configured to couple a DC voltage to the electrode to form a ballistic electron beam through the plasma; A controller configured to control the gas supply system / RTI > The AC power system and the DC power system, Treating the mask layer in the plasma processing system by exposing the mask layer to an oxygen containing plasma, a halogen containing plasma, or a rare gas plasma, or a combination of two or more thereof, without forming a ballistic electron beam. Processing steps, Subsequent to the processing step of processing the mask layer, forming a plasma and a ballistic electron beam in the plasma processing system to etch the thin film and transfer the pattern of the patterned mask layer to the thin film. Plasma processing system. An etching method for etching a thin film formed on a substrate and patterned with a mask layer thereon, Forming a protective layer on the mask layer to protect the mask layer; An etching step of etching the thin film to transfer the pattern of the mask layer to the thin film following the forming step of forming the protective layer Including, The etching step, Forming a plasma in the plasma processing system from the process gas; Coupling a direct current (DC) power to an electrode in the plasma processing system to form an electron beam supporting the plasma in the plasma processing system during the etching step; And exposing the substrate to the plasma and the electron beam. 27. The method of claim 25, wherein forming said protective layer comprises exposing said mask layer to a deposition gas plasma. 27. The method of claim 26, wherein the forming of the protective layer comprises exposing the mask layer to a hydrocarbon-containing plasma or a fluorocarbon-containing plasma, or a hydrofluorocarbon-containing plasma, or a combination of two or more thereof. Etching method. The method of claim 26, wherein the forming of the protective layer comprises C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ , C ₆ H ₁₂ , C ₂ F ₆ , CF ₄ , C ₃ The mask layer in a plasma formed using F ₈ , C ₄ F ₈ , C ₅ F ₈ , C ₄ F ₆ , CH ₂ F ₂ , CHF ₃ , CH ₃ F, C ₂ HF ₅ , or a combination of two or more thereof Etching step of exposing the light. The method of claim 28, wherein the forming step comprises exposing the mask layer to H ₂ , O ₂ , CO, CO ₂ , NO, N ₂ O, NO ₂ , N ₂ , CN, an inert gas, or a combination of two or more thereof. And further comprising an exposure step. 27. The method of claim 26, wherein said forming step of forming said protective layer comprises an immersion step of immersing said mask layer in alcohol. 27. The method of claim 26, wherein said forming step of forming said protective layer comprises an immersion step of immersing said mask layer in ethanol, methanol, or both. 27. The plasma forming system of claim 26, wherein the forming step of forming the protective layer comprises: forming a plasma formed in the plasma processing system by coupling AC power to the electrode or another electrode other than the electrode, the substrate holder, or a combination of two or more thereof. And exposing the mask layer to an exposure step. 33. The method of claim 32, wherein exposing the mask layer to a plasma comprises exposing the mask layer to a low power plasma formed using a power level of at least 500 W. 27. The method of claim 26, wherein exposing the mask layer to the plasma comprises exposing the mask layer to a plasma formed at a remote plasma source coupled to the plasma processing system. 27. The method of claim 25, wherein said combining step of combining DC power comprises combining a DC power in a voltage range of -2000 V to 1000 V. 27. The method of claim 25, wherein the coupling step of coupling the DC power comprises a coupling step of coupling a DC power having a negative polarity, wherein the absolute value of the DC power is at least 500V. 27. The method of claim 25, wherein said coupling step of coupling the DC power comprises coupling the DC power to an upper electrode opposite the substrate installed in the substrate holder. 38. The method of claim 37, wherein forming the plasma comprises coupling a high frequency (RF) power to the electrode or another electrode other than the electrode, or a substrate holder, or a combination of two or more thereof. Etching method. 39. The method of claim 38, wherein the combining step of combining RF power comprises: combining a first RF power of a first RF frequency to the upper electrode, and a second of a second RF frequency less than the first RF frequency. And a coupling step of coupling the RF power to the substrate holder. 39. The method of claim 38, And a modulating step of modulating the amplitude of the RF power to adjust the spatial distribution of the electron beam flux relative to the electron beam. 27. The method of claim 25, wherein said forming step of forming said protective layer on said mask layer prior to said etching step reduces LER formed in said mask layer during said etching step. 27. The method of claim 25, wherein the forming of the protective layer comprises: coupling a first RF power of a first RF frequency to an upper electrode and receiving a second RF power of a second RF frequency that is less than the first RF frequency. Forming a deposition plasma by coupling to a substrate holder, wherein the first RF power is at least 500 W and the second RF power is at most 100 W. 43. The method of claim 42 wherein the second RF power is zero. An etching method for etching a thin film formed on a substrate and patterned with a mask layer thereon, Forming a protective layer on the patterned mask layer, wherein the protective layer has a predetermined thickness to protect the mask layer during a ballistic electron beam assisted plasma etching process; Following the forming step of forming the protective layer, performing the ballistic electron beam assisted plasma etching process on the substrate to etch the thin film and transfer the pattern of the mask layer to the thin film. / RTI > The predetermined thickness ranges from 1 nm to 200 nm. 45. The method of claim 44, wherein the predetermined thickness ranges from 50 nm to 100 nm. A plasma processing system configured to etch a thin film formed on a substrate and having a mask layer patterned thereon, the method comprising: A processing chamber, A gas supply system configured to supply gas to the processing chamber; A substrate holder coupled to the processing chamber and configured to support the substrate; An electrode provided inside the processing chamber; An AC power system coupled to the processing chamber and configured to couple at least one AC signal to the substrate holder, the electrode, or both to form a plasma within the processing chamber; A DC power system coupled to the processing chamber and configured to couple a DC voltage to the electrode to form a ballistic electron beam through the plasma; A controller configured to control the gas supply system / RTI > The AC power system and the DC power system, Forming a protective layer on the mask layer to protect the mask layer; Following the forming step of forming the protective layer, performing a forming step of etching the thin film and forming a plasma and a ballistic electron beam in the plasma processing system to transfer a pattern of a patterned mask layer to the thin film. Processing system. An etching method for etching a thin film formed on a substrate and patterned with a mask layer thereon, Treating the mask layer with a pre-etched electron beam in the absence of an atomic halogen species to modify the mask layer; Following the processing step of processing the mask layer, an etching step of etching the thin film in a plasma processing system to transfer the pattern of the mask layer to the thin film. / RTI > The etching step may include forming an etching plasma from the etching gas; Coupling a direct current (DC) power to an electrode in the plasma processing system to form an etch electron beam supporting the etch plasma during the etch step; And exposing the substrate to the etching plasma and the etching electron beam. 48. The method of claim 47, wherein the processing step of processing the mask layer by the pre-etched electron beam comprises: placing the substrate in the plasma processing system; and generating an electron beam source coupled to the plasma processing system. And treating the mask layer using the mask. 48. The method of claim 47, wherein processing the mask layer with the pre-etched electron beam comprises: placing the substrate in a substrate processing system other than the plasma processing system, and coupled to the substrate processing system. And treating said mask layer using an electron beam source. 48. The method of claim 47, wherein the processing step of processing the mask layer by the pre-etched electron beam, Placing the substrate on a substrate holder in the plasma processing system; A forming step of forming a pre-etch plasma in the plasma processing system from the pre-etch gas; Coupling a DC power to the electrode in the plasma processing system to form the electron beam for pre-etching; And exposing the substrate to the pre-etch plasma and the pre-etch electron beam. 51. The method of claim 50, wherein said forming of said pre-etching plasma comprises forming said pre-etching plasma from one or more rare gases. 53. The method of claim 51, wherein said forming step of forming the pre-etch plasma includes forming the pre-etch plasma from a mixture of one or more rare gases and CHF ₃ . 51. The method of claim 50, wherein the forming step of forming the electron beam for pre-etching includes coupling a DC power to an upper electrode opposite the substrate on the substrate holder. 51. The method of claim 50, wherein the forming step of forming the electron beam for preetching includes a coupling step of coupling a DC power having a negative polarity, wherein an absolute value of the DC power is at least 500 V. . 51. The method of claim 50, wherein the forming step of forming the plasma for pre-etching includes coupling a high frequency (RF) power to the electrode, another electrode other than the electrode, the substrate holder, or a combination of two or more thereof. And the total power level of the RF power is 500 W or less. 48. The method of claim 47, wherein forming the etch electron beam comprises a coupling step of coupling a DC power in a voltage range of -2000 V to 1000 V. 48. The method of claim 47, wherein forming the etching electron beam comprises a coupling step of coupling a DC power having a negative polarity, wherein the absolute value of the DC power is at least 500V. 48. The method of claim 47, wherein forming the etch electron beam comprises a coupling step of coupling a DC power to an upper electrode opposite the substrate installed in the substrate holder. 59. The method of claim 58, wherein forming the etching plasma comprises combining a high frequency (RF) power to the electrode, another electrode other than the electrode, the substrate holder, or a combination of two or more thereof. Phosphorus etching method. 60. The method of claim 59, wherein the combining step of combining RF power comprises: combining a first RF power of a first RF frequency to the upper electrode, and a second of a second RF frequency that is less than the first RF frequency. And a coupling step of coupling the RF power to the substrate holder. 60. The method of claim 59, And a modulating step of modulating the amplitude of the RF power to adjust the spatial distribution of the electron beam flux relative to the electron beam. 48. The method of claim 47, wherein said processing step of treating said mask layer with said pre-etched electron beam prior to said etching step reduces LER formed in said mask layer during said etching step. 48. The method of claim 47, wherein said processing step is performed for a predetermined time period so that a patterned mask layer is resistant to LER formed in said mask layer during said etching step. 48. The method of claim 47, wherein the electron beam energy of the electron beam for preetch is less than the electron beam energy of the electron beam for etching. 48. The method of claim 47, wherein the electron beam energy of the pre-etched electron beam has an increase or slope in one or more steps during the processing step of processing the mask layer by the pre-etched electron beam. An etching method for etching a thin film on a substrate using a plasma processing system having a ballistic electron beam, A forming step of forming a mask layer having a predetermined pattern on the thin film; Forming a first electron beam in the absence of an atomic halogen species; Exposing the substrate having the mask layer to the first electron beam to treat the mask layer; Forming an etching plasma in said plasma processing system from an etching gas; Forming a second electron beam in the plasma processing system; An exposure step of exposing the substrate to the etching plasma and the second electron beam to transfer the pattern to the thin film Etching method comprising a. A plasma processing system configured to etch a thin film having a mask layer on a substrate, the plasma processing system comprising: A processing chamber, A gas supply system configured to supply gas to the processing chamber; A substrate holder coupled to the processing chamber and configured to support the substrate; An electrode provided inside the processing chamber; An AC power system coupled to the processing chamber and configured to couple at least one AC signal to the substrate holder or the electrode, or both, to form a plasma within the processing chamber; A DC power system coupled to the processing chamber and configured to couple a DC voltage to the electrode to form a ballistic electron beam through the plasma; A controller configured to control the gas supply system / RTI > The AC power system and the DC power system, Treating the mask layer with a pre-etched electron beam in the absence of an atomic halogen species to modify the mask layer; Subsequent to the processing step of processing the mask layer, forming a plasma and a ballistic electron beam in the plasma processing system to etch the thin film and transfer the pattern of the patterned mask layer to the thin film. Plasma processing system.

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