JP5271267B2 - Mask layer processing method before performing etching process - Google Patents

Description

  The present invention relates to a method for etching a thin film on a substrate in a plasma processing system. More particularly, the present invention relates to a method of treating a mask layer on a thin film prior to etching the thin film using a plasma assisted by a ballistic electron beam.

  During semiconductor processing, a (dry) etching process may be utilized to remove or etch material patterned along a fine line on a silicon substrate or within a via or contact. Plasma etching processes generally include providing a semiconductor substrate covered with a patterned protective layer, such as a photoresist layer, in a processing chamber. Once the substrate is in the chamber, an ionizable and decomposable gas mixture is introduced into the chamber at a predetermined flow rate. Meanwhile, the vacuum pump is throttled to reach the surrounding process pressure.

Thereafter, plasma is generated when some of the gas species present are ionized by heated electrons. The heating is realized by capacitively or inductively transporting radio frequency (RF) power or by microwave power, for example using electron cyclotron resonance (ECR). Moreover, the heated electrons play a role in decomposing some of the surrounding gas species and generating reactive species (s) suitable for the chemistry that etches the exposed surface. Once the plasma is generated, selected surfaces of the substrate are etched by the plasma. The process is adjusted to achieve the appropriate conditions. Appropriate conditions include the appropriate concentration of reactants and ions required to etch various features (eg, trenches, vias, contacts, etc.) in selected areas of the substrate. Such substrate materials that require etching include silicon dioxide (SiO ₂ ), low-k and ultra-low-k dielectric materials, polycrystalline silicon, silicon carbide, and silicon nitride.

U.S. Patent Application No. 11/156559 US Patent Application No. 2006 / 0037701A1 International Publication No. 2008/016747 Pamphlet

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

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

  These and / or other objects of the present invention are provided by a method of etching a thin film having a mask layer formed on a substrate and patterned thereon. The method includes a step of treating the mask layer by exposing the mask layer to oxygen-containing plasma, halogen gas-containing plasma, rare gas-containing plasma, or a mixed plasma of two or more of these, and the mask layer A step of etching the thin film in order to transfer the pattern of the mask layer to the thin film. The etching step includes generating a plasma from a processing gas in a plasma processing system, coupling a direct current (DC) output to an electrode in the plasma processing system, and generating an electron beam that supports the plasma during the etching step. Generating inside the plasma processing system, and exposing the substrate to the plasma and the electron beam.

  Another aspect of the present invention includes a method for etching a thin film having a mask layer formed on a substrate and patterned thereon. The method includes providing a substrate on a substrate holder in a plasma processing system equipped to generate a plasma and a ballistic electron beam, and an oxygen-containing plasma, a halogen gas-containing plasma, or a rare gas-containing plasma, Or exposing the mask layer to a mixed plasma of two or more of these to process the mask layer without generating a ballistic electron beam. Further, following the step of processing the mask layer, plasma and ballistic electron beams are generated in the plasma processing system to etch the thin film and transfer the patterned mask layer pattern to the thin film. .

  In yet another aspect, a plasma processing system provided to etch a substrate includes a processing chamber, a gas supply system provided to supply gas to the processing chamber, and the substrate coupled to the processing chamber. A substrate holder provided to process the substrate, and an electrode provided inside the processing chamber. An AC output system is provided to couple with the processing chamber and to couple at least one AC signal to the substrate and / or the electrode to generate a plasma within the processing chamber. A DC output system is provided to couple to the processing chamber and to couple a DC voltage to the electrode to generate an electron beam through the plasma. A control device is provided to control the gas supply system, the AC output system, and the DC output system to cause the gas supply system, the AC output system, and the DC output system to perform the following steps. ing. The following steps are: without generating a ballistic electron beam by exposing the mask layer to oxygen-containing plasma, halogen gas-containing plasma, rare gas-containing plasma, or a mixed plasma of two or more of these. Following the steps of processing the mask layer; and processing the mask layer, in the plasma processing system for etching the thin film and transferring the pattern of the patterned mask layer to the thin film. Generating a plasma and a ballistic electron beam.

1 shows a schematic diagram of a plasma processing system according to an embodiment of the present invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the invention. 6 shows a substrate processing method using plasma according to another embodiment of the present invention.

  In the following description, specific details such as the structure of the plasma processing system and descriptions of various processes will be described for the purpose of non-limiting description. However, it should be noted that the invention may be practiced in other embodiments that depart from these specific details.

  In the material processing method, pattern etching provides a mask for transferring this pattern to an underlying thin film provided on the substrate during etching, so that a photosensitive material- Having a procedure of applying a thin layer of photoresist. Photosensitive material patterning generally involves exposure by a radiation source, for example through a reticle (and related optics) of the photosensitive material using, for example, microlithography, followed by an exposed area of the photosensitive material using a developer solution ( (For positive resist) or removal of non-irradiated areas (for negative resist). Moreover, the mask layer may have a plurality of layers.

  A dry etching process is often used during pattern etching. In a dry etching process, the process gas is subjected to electromagnetic (EM) energy, such as radio frequency (RF) output, to heat the electrons and subsequently cause ionization and decomposition of the atomic and / or molecular composition of the process gas. A plasma is generated from the process gas by combining the negative ions. In addition, a negative high voltage direct current (DC) output is generated to generate a ballistic electron beam that illuminates the substrate surface during part of the RF cycle, that is, during the positive half cycle of the combined RF output. It may be coupled to a plasma processing system. Ballistic electron beams can improve the characteristics of the dry plasma etching process, for example, by improving the etch selectivity between the underlying thin film (to be etched) and the mask layer. This reduces charge damage, such as electronic shading damage. Further details regarding the generation of a ballistic electron beam are disclosed in US Pat.

  Referring now to FIG. 1, a schematic diagram of a plasma processing system with a ballistic electron beam is provided. The plasma processing system includes a first electrode 120 and a second electrode 172 provided to face each other inside the processing chamber. The first electrode 120 is provided to support the substrate 125. A first electrode 120 is coupled to a first RF generator 140 that is equipped to provide an RF output at a first RF frequency. On the other hand, the second electrode 172 is coupled to a second RF generator 170 that is equipped to provide an RF output at a second RF frequency. For example, the second RF frequency may be the same as or different from the first RF frequency. For example, the second RF frequency may be higher than the first RF frequency. The coupling of the RF power to the first and second electrodes aids in the generation of plasma 130.

  In addition, the plasma processing system includes a DC power supply 150 that is equipped to provide a DC voltage to the second electrode 172. Here, the coupling of the negative DC voltage to the second electrode 172 helps to generate the ballistic electron beam 135. The coupling of a negative DC voltage to the second electrode 172 (for example) helps generate the ballistic electron beam 135. The electron beam output is obtained from the superposition of negative DC voltage at the second electrode 172. As described in Patent Document 2, application of a negative DC output to the plasma processing system affects the generation of a ballistic (non-collision) electron beam that irradiates the surface of the substrate 125.

  In general, the ballistic electron beam may be implemented by any type of plasma processing system, as described below. In this example, a negative DC voltage is superimposed in an RF output capacitively coupled plasma (CCP) processing system. Therefore, the present invention is not limited by this example. This example is for illustrative purposes only.

While ballistic electron beams are important for etching properties, we often use striking electron beams to cause striations or pattern anomalies (usually referred to as “line edge roughness” (LER)). It was observed that the development inside the mask layer was caused. In particular, we find that LER frequently occurs with low polymer production (eg, relatively low CF ₂ radical content) etch chemicals (eg, CF ₄ ) and high polymer production (eg, CF ₂ radical content). It has been observed that it does not occur frequently with relatively high etching chemicals (eg C ₄ F ₈ or C ₅ F ₈ ). Such pattern anomalies and sidewall roughness can be transferred to the underlying layer during the current and / or subsequent etching processes. For example, during the initial exposure of the substrate to an etching process that has an excitation that breaks bonds, such as a ballistic electron beam assisted plasma, the mask layer changes so that the pattern formed in the mask layer has a sidewall roughness. (Ie pattern abnormality). The sidewall roughness is transferred to the film to be etched as the etching process proceeds. As a result, the manufacturing yield may be reduced and / or the performance and reliability of the device may be lowered.

  The inventors have studied the characteristics of ballistic electron beam assisted plasma in order to identify the cause of the LER problem described above. Increasing the exposure time of a mask layer--for example, a photoresist layer--to a strong electron beam (eg, having an electron energy greater than about 100 eV) changes the mask layer, resulting in an etching process as described above. Despite the improvements, the initial exposure to the electron beam has caused damage-electron induced defects that can create striations (hereinafter referred to as LER) in the mask layer when halogen species are present. The present inventors believe that it causes inclusion. For example, when the mask layer is exposed to the fluorine-containing etching chemicals described above, the chemical bond breakage at the surface layer of the mask layer is determined by the oxidation of the fluorine as well as from the mask layer surface (by the energy of the incident electrons. Cause removal of carbon, hydrogen, and oxygen to a certain depth. In general, in conventional ballistic electron beam etching processes, the presence of a ballistic electron beam is present even though it is advantageous for the etching process to continue exposure to halogen atom species in the presence of the ballistic electron beam. We believe that the initial exposure of the mask layer to the underlying halogen atom species causes LER.

  Thus, the inventors expect that the LER progression during the etching process can be reduced by treating the mask layer before the etching process. The mask layer may have a silicon-containing layer or a non-silicon-containing layer. In addition, the mask layer may comprise a photosensitive material such as a photoresist. For example, the mask layer may be a 248 nanometer (nm) photoresist, a 913 nanometer (nm) photoresist, a 157 nanometer (nm) photoresist, EUV (extreme ultraviolet photoresist), or a mixture of these. A resist may be included.

  According to one embodiment, the patterned mask layer is subjected to an oxygen-containing plasma, or a halogen plasma, or a noble gas plasma prior to performing an etching process that transfers the pattern formed in the mask layer to the underlying thin film. Or are exposed to a mixed plasma thereof. The mask layer is treated with an oxygen-containing plasma, or a halogen plasma, or a rare gas plasma, or a mixed plasma thereof in the absence of excitation—such as strong electrons or photons—that would break the bond. The processing plasma is preferably a plasma that bombards the patterned mask with little or no strong ions (ie, low energy ions at the substrate). Thus, the radio frequency (RF) or microwave power provided to the plasma source is preferably provided at a power level sufficient to decompose and ionize oxygen or halogen gas and ionize noble gas. In one embodiment, the power to the plasma source is desirably about 2000 W or less and the power to the plasma source is desirably about 500 W or less. In addition, the bias output to the substrate electrode should be less than about 500 W, the bias output to the substrate electrode should be less than about 100 W, and the bias output should not substantially apply power to the substrate electrode. More desirable. Further, it is desirable that the processing plasma be performed for about 1-30 seconds and the processing plasma be performed for about 2-20 seconds, such as about 10 seconds.

  The exposure of the mask layer may be performed within a plasma processing system utilized in the etching process, such as the plasma processing system illustrated in FIG. Alternatively, the exposure may be performed in a substrate processing system other than the plasma processing system in which the etching process is performed. The plasma may be generated in situ by using a plasma generation system that assists in generating the plasma during the etching process. Alternatively, the plasma is generated outside the plasma processing chamber in which such exposure takes place by using a plasma processing system in which the etching process takes place, or a remotely located plasma generation system that couples with a separate substrate processing system. May be.

The oxygen-containing plasma may be generated from O ₂ , CO, CO ₂ , NO, N ₂ O, or NO ₂ , or a mixture of two or more of these. The oxygen-containing gas may have a flow rate between about 10 sccm (cl ³ / min at normal conditions) to about 1000 sccm—for example about 100 sccm to 300 sccm—. The chamber pressure can be from about 1 mTorr to about 1000 mTorr. Also desirably, the chamber pressure may be between about 50 mTorr and about 500 mTorr. More desirably, the chamber pressure may be between about 100 mTorr and about 500 mTorr. The oxygen-containing plasma may further include an inert gas, a rare gas, N ₂ , H ₂ , or CN. The inventors believe that the use of oxygen-containing plasma can facilitate the generation of sub-layers within the mask layer with increased oxygen concentration. We expect that the mask layer thus treated will help reduce 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 that is expected to be particularly resistant to LER generation may be formed.

  In one example, the treatment of the mask layer with the oxygen-containing plasma is performed in a plasma processing chamber in which an etching process is performed. The process conditions are oxygen-containing gas flow rate in the range of about 100 scc to about 500 sccm, chamber pressure of about 100 mTorr or more, RF bias power applied to the bottom electrode (present on the substrate) with little or no application, about 500 W. RF power to the top electrode (or induction coil) and processing time that is about 10 seconds may be included. In another example, treatment of the mask layer with an oxygen-containing plasma is performed using a plasma source (ie, a remote plasma source) outside the plasma processing chamber in which the etching process is performed, eg, a microwave power plasma source. The process conditions are oxygen-containing gas flow rate in the range of about 100 scc to about 500 sccm, chamber pressure of about 100 mTorr or more, RF bias power applied to the bottom electrode (present on the substrate) with little or no, about 1000 W. RF power to the top electrode (or induction coil) and processing time that is about 10 seconds may be included.

Halogen-containing plasma can be 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 mixture of two or more gases. May be generated. The halogen-containing gas may have a flow rate between about 10 sccm and about 1000 sccm, such as between about 100 sccm and 300 sccm. The chamber pressure can be from about 1 mTorr to about 1000 mTorr. Also desirably, the chamber pressure may be from about 20 mTorr to about 500 mTorr. More desirably, the chamber pressure may be between about 20 mTorr and about 100 mTorr. The halogen-containing plasma may further include a noble gas, N ₂ , H ₂ , or CN. In addition, the halogen-containing plasma may further comprise an oxygen-containing plasma. Exposing the mask layer to a halogen-containing plasma in the absence of an intense electron beam deactivates the surface layer of the mask layer, thereby helping to reduce LER in the mask layer in subsequent etching processes. The inventors expect.

  In one example, the processing of the mask layer with the halogen-containing plasma is performed in a plasma processing chamber in which an etching process is performed. Process conditions include halogen-containing gas flow rates that range from about 100 scc to about 500 sccm, chamber pressures that range from about 25 mTorr to about 50 mTorr, RF bias output that is not or hardly applied to the bottom electrode (present on the substrate), RF power to the upper electrode (or induction coil) that is about 100W to about 500W, and a processing time that is about 10 seconds. In another example, treatment of the mask layer with a halogen-containing plasma is performed using a plasma source outside the plasma processing chamber in which the etching process is performed (ie, away from the chamber), such as a microwave power plasma source. The process conditions are a halogen-containing gas flow rate in the range of about 100 scc to about 500 sccm, a chamber pressure that is about 100 mTorr or more, an RF bias output that is not or hardly applied to the bottom electrode (present on the substrate), about 1000 W. RF power to the top electrode (or induction coil) and processing time that is about 10 seconds may be included.

  The rare gas plasma may be generated from a rare gas, such as He, Ne, Ar, Xe, Kr, or a mixture of two or more of these. The noble gas may have a flow rate between about 10 sccm and about 1000 sccm, such as between about 100 sccm and 300 sccm. The chamber pressure can be from about 1 mTorr to about 1000 mTorr. Also desirably, the chamber pressure may be between about 50 mTorr and about 500 mTorr. More desirably, the chamber pressure may be between about 50 mTorr and about 200 mTorr. The present inventor said that the use of a noble gas plasma facilitates the generation of a carbon-rich, ie “carbonized”, surface layer on the mask layer (ie, a surface layer lacking O and H, for example). Are thinking. The “carbonized” surface layer may extend deep into the mask layer by a few nanometers (nm) (eg, 1-10 nm) depending on the ion energy of the ions that impact the mask layer. For example, ions having an energy in the range of about 25 to about 50 eV should penetrate to a depth of about 1 nm to about 2 nm. We expect that the mask layer thus treated will help reduce LER in the mask layer in subsequent etching processes.

  In one example, the processing of the mask layer with the noble gas plasma is performed in a plasma processing chamber in which an etching process is performed. Process conditions include noble gas flow rates that range from about 100 scc to about 300 sccm, chamber pressures that range from about 25 mTorr to about 50 mTorr, RF bias output that is not or hardly applied to the bottom electrode (present on the substrate), about RF power to the upper electrode (or induction coil) that is 100W to about 500W, and a processing time that is about 10 seconds. In another example, treatment of the mask layer with a halogen-containing plasma is performed using a plasma source outside the plasma processing chamber in which the etching process is performed (ie, away from the chamber), such as a microwave power plasma source. Process conditions include oxygen-containing gas flow rates that range from about 100 scc to about 500 sccm, chamber pressure that is greater than about 100 mTorr, RF bias power that is not applied to the bottom electrode (present on the substrate) or little, about 500 W to about RF power to the top electrode (or induction coil) that is 1000 W, and processing time that is about 10 seconds.

  According to another embodiment, a protective layer is formed on the mask layer prior to performing an etching process that transfers the pattern produced in the mask layer to the underlying thin film. The protective layer formed on the mask layer may comprise a material layer that can (partially) disappear during the etching process. Thereby, the protective layer can protect the mask layer during the early stages of the etching process. Alternatively, a protective layer formed on the mask layer may increase the etching resistance during the etching process, particularly at an early stage of the etching process.

  Formation of the protective layer on the mask layer may be performed within a plasma processing system utilized in the etching process, such as the plasma processing system illustrated in FIG. Alternatively, the exposure may be performed in a substrate processing system other than the plasma processing system in which the etching process is performed. The plasma may be generated in situ by using a plasma generation system that assists in generating the plasma during the etching process. Alternatively, the plasma is generated outside the plasma processing chamber in which such exposure takes place by using a plasma processing system in which the etching process takes place, or a remotely located plasma generation system that couples with a separate substrate processing system. May be.

Deposition gas plasma is utilized when forming a protective layer on the mask layer. The result of exposing the mask layer to the deposition gas plasma is a net deposition of material on the substrate surface. Formation of the protective layer on the mask layer includes exposure of the mask layer to a deposition gas plasma. The deposition gas plasma is, for example, a hydrocarbon-containing plasma (that is, a C _x H _y- containing plasma. _X and y represent an integer of 1 or more), or a fluorocarbon-containing plasma (that is, a C _x F _z- containing plasma, where x and z are 1 represents an integer of 1 or more), or a hydrofluorocarbon-containing plasma (that is, C _x H _y F _z- containing plasma. _X , y and z represent an integer of 1 or more), or a mixed plasma of two or more of these. . The mask layer is processed by depositing a gas plasma in the absence of excitation—such as strong electrons or photons—that would break the bonds. C _{x Hy} containing plasma is C ₂ H ₄ , CH ₄ , 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 ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ , or C ₆ H ₁₂ , or a mixture of two or more of these. C _x F _z-containing plasma is generated by using a _{C 2 F 6, CF 4,} C 3 F 8, C 4 F 8, C 5 F 8, or C ₄ F _6, or mixtures of two or more types thereof Good. C _x H _y F _z containing _{plasma, CH 3 F, C 2 HF} 5, CH 2 F 3, or CHF _3, or may be generated by using a combination of two or more thereof.

The process conditions are selected to form a protective layer of hydrocarbon, fluorocarbon, or a mixture thereof on the mask layer by using one or more of the deposition gases described above. The process conditions must be chosen so that the pattern formed in the mask layer is not confined, i.e. not blocked. The protective layer may cover a flat area. In addition, the protective layer may have a certain amount of protrusions on the pattern, and may further have a portion covering the side wall of the pattern in the mask layer. For example, the process conditions must be chosen to produce an ion deposited plasma that has little or no sputtering (ie, low ion energy at the substrate surface). The deposition gas may have a flow rate between about 10 sccm and about 1000 sccm. Desirably, the deposition gas may have a flow rate between about 100 sccm and 300 sccm, such as 200 sccm. The chamber pressure can be from about 1 mTorr to about 1000 mTorr. Also desirably, the chamber pressure may be between about 50 mTorr and about 500 mTorr. More desirably, the chamber pressure may be between about 100 mTorr and about 500 mTorr. In addition, the deposition gas plasma may further comprise a diluent gas, such as a noble gas. For example, the deposition gas flow rate may range from about 1% to about 20% of the gas mixture, while the remaining components have a dilution gas flow rate. In addition, for example, the deposition gas flow rate can range from about 5% to about 10% of the gas mixture, while the remaining components have a dilution gas flow rate. Further, the deposition gas may also include H ₂ , O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂ , CN, or an inert gas, or a mixture of two or more of these.

In one example, when depositing a CF (ie C _x F _z ) polymer, the deposition gas—such as C ₄ F ₈ or C ₄ F ₆ , may or may not have CF _4. Also good-may be used. Process conditions include a dilution gas flow rate that ranges from about 100 scc to about 500 sccm, a deposition gas flow rate that ranges from about 1% to about 20% of the dilution gas flow rate, a chamber pressure that ranges from about 50 mTorr to about 200 mTorr, RF bias output with little or no applied to the bottom electrode (present on the substrate), RF power to the top electrode (or induction coil) that is about 500 W to about 1000 W, and a thickness of about a few nm to about 200 nm There may be sufficient processing time to produce the film.

In another example, when depositing a CH (i.e. C _x H _y) polymer, process conditions, the range the flow rate of the dilution gas in the range of about 100scc~ about 500 sccm, from about 1% dilution gas flow rate of about 20% Deposition gas flow rate, chamber pressure in the range of about 50 mTorr to about 200 mTorr, RF bias output with little or no application to the bottom electrode (present on the substrate), top electrode (or induction) of about 500 W to about 1500 W RF power to the coil) and a processing time sufficient to produce a film having a thickness of about a few nm to about 200 nm.

  The required thickness of the protective layer is considered to be greater for the CH film than for the CF film. This is because the present inventors consider that the CF film can provide a relatively strong etching resistance during the etching process. The minimum thickness of the protective layer must be chosen according to the depth of the charged species in the etching process. For example, a film having a thickness of about 50 nm is required for an electron beam of 1 keV, and a film having a thickness of about 100 nm is required for an electron beam of 1.5 keV.

  In yet another example, forming the protective layer on the mask layer may include a step of immersing the mask layer in an alcohol such as methanol or ethanol.

  By forming a protective layer on the mask layer by using a hydrocarbon-based chemical or a hydrofluorocarbon-based chemical, the hydrogen content on the mask layer surface is increased, resulting in an early stage of the etching process. We expect that strong electrons will be weakened. By mitigating the strong electron damage effects during these early stages of the etching process, the sacrificial layer can help reduce LER in the mask layer in subsequent etching processes. In addition, forming a protective layer on the mask layer by using a hydrofluorocarbon-based chemical or a fluorocarbon-based chemical creates a polymer film that provides additional etch resistance to the mask layer during the etching process. Help. Improving the etch selectivity for the modified mask layer helps to reduce the LER in the mask layer in subsequent etching processes.

  According to yet another embodiment, the mask layer is treated with an electron beam in the absence of halogen atom species (ie, F, Cl, Br, etc.) prior to performing the etching process. By exposing the mask layer to an electron beam in the absence of halogen atom species, the surface of the mask layer is “cured” or hardened so that the mask layer is resistant to LER generation during the etching process. The inventors expect that they will be less affected.

  Exposure of the mask layer to the electron beam may occur in a plasma processing system in which the etching process is performed, such as the plasma processing system illustrated in FIG. Alternatively, the exposure may be performed in a plasma processing system other than the plasma processing system in which the etching process is performed. For example, the electron beam source may be combined with a plasma processing system (for an etching process) or other substrate processing system. Also, for example, an electron beam source may be provided to generate an electron beam for processing the mask layer.

  Alternatively, for example, the electron beam can couple its direct current (DC) output to an electrode within the plasma processing system (as illustrated in FIGS. 1 and 2-7) and generate the plasma by generating a plasma. It may be generated inside the processing system. Referring to FIG. 1, a pre-etch plasma may be generated by coupling an alternating current (AC) output—eg, a radio frequency (RF) output—to the first electrode 120 and / or the second electrode 172. The pre-etch electron beam may also be generated by coupling the DC output to the second electrode 172.

By using a pre-etch electron beam, the surface layer of the mask layer can be treated before the etching process. The processing depth can range from about 1 nm to about 100 nm. Desirably, the processing depth may be in the range of about 5 nm to about 50 nm, such as 10 nm. These travel depths can be achieved by using electron beam energy that ranges from about 500 eV to about 1.5 keV. The energy of the pre-etch electron beam can be up to about 1.5 keV. Desirably, the energy of the pre-etch electron beam may be in the range of about 200 eV to about 1.5 keV, such as 500 eV. Pre-etching electron beam exposure can be selected to generate an electron irradiation amount in the range of about 10 ¹⁴ / per square centimeter (cm ^-2) ~ about 10 ¹⁶ cm ^-2.

  In one example, the pre-etch electron beam is generated in the plasma processing system of FIG. Process conditions include noble gas flow rates ranging from about 100 sccc to about 300 sccm, chamber pressure ranging from about 20 mTorr to about 100 mTorr, RF bias power applied to the bottom electrode (existing on the substrate) with little or no application, about RF power to the top electrode (or induction coil) that is 500W to about 1000W, DC voltage to the top electrode that is in the range of about -500V to about -1000V, and processing time that is about 10 seconds. .

The pre-etch plasma may be generated by using an inert gas such as a rare gas (ie, He, Ne, Ar, Xe, Kr). In addition, the pre-etch plasma may further include CHF ₃ . In the presence of plasma, the decomposition of CHF ₃ tends to produce a lot of CF ₂ (polymer-forming radicals) and (ion-binding) HF. The polymer-forming radicals can be advantageous for mask layer processing by providing a sacrificial layer as described above. However, in order to process the mask layer while mitigating the above-mentioned LER problem, the added gas (to the inert plasma generation gas (s)) should be free of halogen atom species in the presence of plasma. Must be chosen.

  The mask layer may be treated with a pre-etch electron beam and a pre-etch plasma for a predetermined period of time, for example, about 10 seconds. Further, the pre-etch electron beam is performed for about 1-30 seconds. Desirably, the pre-etch electron beam is performed for about 2 to 20 seconds, such as about 10 seconds. After this treatment, an etching plasma may be generated by using an etching gas, an etching electron beam may be generated, and the etching process may etch the substrate having the mask layer to be processed with the etching plasma. It can be proceeded by exposure to an electron beam. The energy of the electron beam before etching may be selected to be approximately equal to the energy of the etching electron beam. Alternatively, the energy of the pre-etching electron beam may be chosen to be less than the energy of the etching electron beam. For example, the energy of the pre-etch electron beam can be about 500 eV. On the other hand, the energy of the etching electron beam may be about 1500 eV. The energy of the electron beam (or the voltage applied to the second electrode 172 in FIG. 1) may increase stepwise during the pre-etching process. Alternatively, the energy of the electron beam may increase at a constant rate during the pre-etching process. In addition, the energy of the electron beam (or the voltage applied to the second electrode 172 in FIG. 1) may be pulsed. For example, the voltage applied to the second electrode 172 may be a pulse between about 0V and about −2000V. Alternatively, desirably, the voltage may be a pulse between about -100V and about -1500V. Or more desirably, the voltage may be a pulse between about -500V and about -1500V.

  The pre-etching electron beam treatment of the mask layer may also be performed prior to the mask layer treatment using oxygen-containing plasma, halogen-containing plasma, or noble gas plasma. In addition, pre-etching electron beam treatment of the mask layer may also be performed prior to the formation of the protective layer on the mask layer. For example, a pre-etch electron beam may treat the surface of the mask layer to grow the polymer during the formation of the protective layer.

  These embodiments may be implemented in any type of plasma processing system as will be described later.

  Referring now to FIG. 2, a plasma processing system is provided in accordance with the present invention that is equipped to process a mask layer prior to etching the underlying layer using a plasma improved by a ballistic electron beam. A plasma processing system 1 includes a plasma processing chamber 8 provided to assist in the generation of plasma, a substrate holder 2 provided to support the substrate 3 in combination with the plasma processing chamber 8, and the plasma processing chamber The electrode 9 is provided so as to be connected to the plasma and to be in contact with the plasma. In addition, the plasma processing system 1 is provided to couple with the plasma processing chamber 8 and to couple at least one AC signal to the substrate holder 2 and / or the electrode 9 to generate the plasma. An AC output system 4 as well as a DC output system 5 coupled to the plasma processing chamber 8 and provided to couple a DC voltage with the electrode 9 to generate a ballistic electron beam through the plasma It has further.

  The plasma processing system 1 further comprises a process gas distribution system 6 coupled to the plasma processing chamber 8 and provided to introduce any gas described in the above embodiments. Further, the plasma processing system 1 has an evacuation system (not shown) coupled to the plasma processing chamber 8 and provided to exhaust gas from the processing chamber.

  Optionally, the plasma processing system 1 further comprises a control device 7. The controller 7 is coupled to the plasma processing chamber 8, the substrate holder 2, the AC output system 4, the DC output system 5, and the AC output modulation system 6, and executes a process for processing the substrate 3 in the plasma processing chamber 8. In order to do so, it is provided to exchange data with each of the above components. The plasma processing system 1 can assist in the processing of the mask layer on the substrate 3 and / or the etching process of the substrate 3.

  FIG. 3 shows a schematic diagram of a plasma processing system according to another embodiment of the present invention. The plasma processing system 1a includes a plasma processing chamber 10, a substrate holder 20 to which a substrate to be processed 25 is fixed, and a vacuum exhaust system 30. The substrate 25 may be a semiconductor substrate, a wafer, or a liquid crystal display. A plasma processing chamber 10 may be provided to assist the 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) may be used to throttle the evacuation system 30. The plasma may be utilized to generate material specific to a given material process and / or assist in removing material from the exposed surface of the substrate 25. The plasma processing system 1a may be equipped to process any size substrate, such as a 200 mm substrate, a 300 mm substrate, or a larger substrate.

  The substrate 25 may be fixed to the substrate holder 20 by an electrostatic fixing system. Further, the substrate holder 20 may have a heating or cooling system that includes a recirculating fluid stream. The recirculating fluid stream receives heat from the substrate holder 20 during cooling and transports the heat to a heat exchange system (not shown). The recirculating fluid stream also transports heat from the heat exchange system to the fluid stream when heated. Moreover, gas may be supplied to the backside of the substrate 25 via a backside gas system to improve gas gap heat conduction between the substrate 25 and the substrate holder 20. Such a system may be used when temperature control of the substrate with temperature increase or decrease is required. For example, the backside gas system may have a two-zone gas distribution system. In this system, the backside gas (eg, helium) pressure may vary independently between the center and end of the substrate 25. In other embodiments, heating / cooling elements, such as resistance heating elements or thermoelectric heaters / coolers, may be placed in the substrate holder 20 as well as chamber walls of the plasma processing chamber 10 and other components within the plasma processing system 1a. May also be included.

  In the embodiment illustrated in FIG. 3, the substrate holder 20 may have an electrode through which the RF power is coupled with the processing plasma in the processing space 15. For example, the substrate holder 20 may be biased with an RF voltage via an RF output transmission line from the RF generator 40 via the optional impedance matching network 42 to the substrate holder 20. The RF bias may serve to heat the electrons to generate and hold the plasma and / or influence the ion energy distribution function within the sheath. In this configuration, the system may operate as a reactive ion etching (RIE) reactor. In the RIE reactor, the chamber and upper gas injection electrode function as a ground plane. A typical frequency for the RF bias may range from 0.1 MHz to 100 MHz. RF systems for plasma processing are known to those skilled in the art.

  Further, the amplitude of the RF output coupled to the substrate holder 20 may be modulated to affect the change in the spatial distribution of the electron beam bundle relative to the substrate 25. Additional details are described in US Pat.

  Moreover, the impedance matching network 42 serves to improve the transport of RF power to the plasma within the plasma processing chamber 10 by reducing the reflected power. Match network topology (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) output supply 50 coupled to the upper electrode 52 facing the substrate 25. The upper electrode 52 may include an electrode plate. The electrode plate may comprise an electrode plate comprising silicon. Moreover, the electrode plate may comprise a doped silicon electrode plate. The DC output supply may comprise a variable DC output supply. In addition, the DC output supply may comprise a bipolar DC output supply. The DC output supply 50 further comprises a system equipped to monitor and / or regulate and / or control the polarity, current, voltage, or on / off status of the DC output supply 50. good. Once the plasma is generated, the DC power supply 50 helps generate a ballistic electron beam. An electrical filter may be used to separate the RF output from the DC output supply 50.

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

  The vacuum pumping system 30 may include, for example, a turbo molecular vacuum pump (TMP) capable of pumping at a pumping speed of up to 5000 l / sec (or higher) and a gate valve for reducing the chamber pressure. In conventional plasma processing apparatuses used for dry plasma etching, TMP of 1000 to 3000 l / sec is generally used. TMP is useful for low pressure processing, typically less than 50 mTorr. For processing at high pressures (pressures higher than about 100 mTorr), mechanical booster pumps and dry roughing pumps may be used. Further, a chamber pressure monitoring device (not shown) may be coupled to the plasma processing chamber 10. The apparatus for measuring pressure may be, for example, a 628B type Baratron absolute capacitance manometer marketed by MKS Instruments.

  Still referring to FIG. 3, the plasma processing system 1a further includes a controller 90. The control device 90 has a microprocessor, a memory, and a digital I / O port. The digital I / O port has the ability not only to monitor the output from the process system 100 but also to generate a control voltage sufficient to exchange and activate the input of the processing system 1a. Moreover, the controller 90 includes an RF generator 40, an impedance matching network 42, a DC output supply 50, a gas injection system (not shown), a vacuum exhaust system 30, a backside gas supply system (not shown), a substrate / It may be coupled to a substrate holder temperature measurement system (not shown) and / or an electrostatic fixation system (not shown) to exchange information with these components. The program stored in the memory may be used to activate inputs to the above-described components of the plasma processing system 1a according to a process recipe for executing the thin film etching method. An example of the control device 90 is DELL PRECISION WORKSTATION 610 (trademark) sold by Dell Corporation.

  The control device 90 may be installed locally with respect to the plasma processing system 1a, or may be installed at a location remote from the processing system 1 via the Internet or an intranet. Therefore, the control device 90 may exchange data with the plasma processing system 1a by using at least one of a direct connection, an intranet, the Internet, and a wireless connection. The control device 90 may be coupled to, for example, an intranet on the customer side (ie, a device manufacturer), or may be coupled to an intranet on the seller side (ie, a device manufacturer). Further, another computer (that is, a control device, a server, etc.) may exchange data via at least one of a direct connection, an intranet, and the Internet by accessing the control device, for example.

  In the embodiment illustrated in FIG. 4, the plasma processing system 1b can be considered similar to the embodiment of FIG. Furthermore, in addition to these components described in FIG. 3, the plasma processing system 1b is static or mechanical or electrical in order to increase plasma density and / or improve plasma processing uniformity. A rotating magnetic field system 60 may be included. Moreover, the controller 90 may be coupled to the magnetic field system 60 to control the rotational speed and magnetic field strength. The design and implementation of rotating magnetic field systems is well known to those skilled in the art.

  In the embodiment illustrated in FIG. 5, the plasma processing system 1c can be considered similar to the embodiment of FIG. Further, the plasma processing system 1c may further include an RF generator 70. An RF generator 70 is provided to couple the RF output with the upper electrode 52 via an optional impedance matching network 72. A typical frequency for applying RF power to the upper electrode 52 may range from about 0.1 MHz to about 200 MHz. In addition, a typical frequency for applying RF power to the substrate holder 20 (ie, the lower electrode) can range from about 0.1 MHz to about 100 MHz. For example, the RF frequency coupled to the upper electrode 52 may be higher than the RF frequency coupled to the substrate holder 20. Further, the RF output from the RF generator 70 to the upper electrode 52 may be amplitude modulation. Alternatively, the RF output from the RF generator 40 to the substrate holder 20 may be amplitude modulation. Alternatively, both the RF output from the RF generator 70 to the upper electrode 52 and the RF output from the RF generator 40 to the substrate holder 20 may be amplitude modulated. The RF output at high RF frequencies is preferably amplitude modulated. Moreover, the controller 90 is coupled to the RF generator 70 and the impedance matching network 72 in order to control the application of the RF output to the upper electrode 52. The design and implementation of the top electrode is well known to those skilled in the art.

  Still referring to FIG. 5, the DC output supply 50 may be directly coupled to the upper electrode 52. Alternatively, the DC output supply 50 may be coupled to an RF transmission line that extends from the output end of the impedance matching network 72 to the upper electrode 52. An electrical filter may be used to separate the RF output from the DC output supply 50.

  In the embodiment illustrated in FIG. 6, the plasma processing system 1d may be considered similar to the embodiments of FIGS. 2, 3, and 4, for example. The plasma processing system 1d may further include an induction coil 80. The RF output is coupled to the induction coil 80 by an RF generator 82 via an optional impedance matching network 84. The RF power is inductively coupled from the induction coil 80 to the plasma processing region 15 through a dielectric window (not shown). A typical frequency for applying RF power to the induction coil 80 may range from about 10 MHz to about 100 MHz. Similarly, a typical frequency for applying power to the chuck electrode may range from about 0.1 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) may be used to reduce capacitive coupling between the induction coil 80 and the plasma. In addition, the controller 90 is coupled to the RF generator 82 and the impedance matching network 84 to control the application of the output to the induction coil 80. In an alternative embodiment, induction coil 80 may be a “spiral” or “hot cake” coil that communicates with plasma processing region 15 from above, such as a transformer coupled plasma (TCP) reactor. The design and implementation of inductively coupled plasma (ICP) sources or transformer coupled (TCP) plasma sources are well known to those skilled in the art.

  Alternatively, the plasma may be generated using electron cyclotron resonance (ECR). In yet another embodiment, the plasma is generated by generating a helicon wave. In yet another embodiment, the plasma is generated by propagating surface waves. Each plasma source described above is known to those skilled in the art.

  In the embodiment illustrated in FIG. 7, the plasma processing system 1e can be considered similar to the embodiments of FIGS. 3, 4, and 5, for example. The plasma processing system 1e may further include a second RF generator 44. A second RF generator 44 is provided to couple the RF output to the substrate holder 20 via any other impedance matching network 46. For the first RF generator 40 and / or the second RF generator 44, a typical frequency for applying RF power to the substrate holder 20 may range from about 0.1 MHz to about 200 MHz. The RF frequency for the second RF generator 44 may be higher than the RF frequency for the first RF generator 40. Furthermore, the RF output from the first RF generator 40 to the substrate holder 20 may be amplitude modulated. Alternatively, the RF output from the second RF generator 44 to the substrate holder 20 may be amplitude modulation. Alternatively, both the RF output from the first RF generator 40 to the substrate holder 20 and the RF output from the second RF generator 44 to the substrate holder 20 may be amplitude modulated. The RF output at high RF frequencies is preferably amplitude modulated. Moreover, the controller 90 is coupled to the second RF generator 44 and the impedance matching network 46 in order to control the application of the RF output to the substrate holder 20. The design and implementation of an RF system for a substrate holder is well known to those skilled in the art.

  In the following discussion, a thin film etching method using a plasma processing system with a ballistic electron beam is shown. For example, the plasma processing system may have various components, such as the components described in FIGS. 1-7 and combinations thereof.

  FIG. 8 shows a flowchart according to a thin film etching method according to an embodiment of the present invention. The procedure 500 begins with a procedure 510 that covers a mask layer on a substrate and that has a pattern in it.

  The mask layer may be processed using any of the above embodiments. For example, treatment of the mask layer may include exposure of the mask layer to an oxygen-containing plasma, a halogen gas-containing plasma, or a rare gas-containing plasma, or a mixture of two or more of these. Alternatively, the treatment of the mask layer may include the formation of a protective layer on the mask layer. Alternatively, the treatment of the mask layer may include exposure of the mask layer to an electron beam in the absence of halogen atom species. Alternatively, the mask layer treatment may comprise a combination of two or more of these treatments described above.

  In step 520, a substrate having a mask layer to be processed is exposed to a dry etching plasma assisted by a strong (ballistic) electron beam to transfer the pattern formed in the mask layer to the underlying thin film. At the same time, pattern abnormalities such as LER are reduced. In a plasma processing system, a (process) plasma is generated from the process gas by coupling output to the process gas (and ionizing and decomposing the process gas). A strong (ballistic) electron beam is generated by coupling the DC power to the electrodes within the plasma processing system and generating a plasma. The energy level of the strong (ballistic) electron beam depends on the magnitude of the DC voltage applied to the electrode.

  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 1000V. Preferably, the absolute value of the DC voltage has a value of about 100V or more. More preferably, the absolute value of the DC voltage has a value of about 500V or more. In addition, it is desirable that the DC voltage has a negative polarity. Furthermore, the DC voltage is preferably a negative voltage having an absolute value larger than the self-bias voltage generated on the electrode surface of the plasma processing system.

  Even if only certain specific embodiments of the present invention have been described in detail, those skilled in the art will readily appreciate that many modifications are possible with little departure from the novel teachings and advantages of the present invention. to understand. Accordingly, it is understood that many such modified types are included within the technical scope of the present invention.

Claims (67)

A method for etching a thin film having a mask layer formed on a substrate and patterned thereon,
The method is:
Treating the mask layer by exposing the mask layer to an oxygen-containing plasma, a halogen gas-containing plasma, a rare gas-containing plasma, or a mixed plasma of two or more thereof, the mask layer comprising: The step of processing is performed in a state where the mask layer is not exposed to an electron beam accelerated by direct current (DC) output; and after the mask layer is processed, the pattern of the mask layer is transferred to the thin film. Etching the thin film;
Have
The etching process includes:
Generating plasma from a process gas in a plasma processing system;
Coupling the direct current (DC) output to an electrode in the plasma processing system to generate an electron beam within the plasma processing system to assist the plasma during the etching process; and Exposing to an electron beam;
Having
Method. The step of treating the mask layer exposes the mask layer to a plasma generated using O ₂ , CO, CO ₂ , NO, N ₂ O, or NO ₂ , or a mixture of two or more of these. 2. The method according to claim 1, comprising a step. Step, N _2, H _2, CN, or an inert gas, or further comprising the step of exposing the mask layer to the two or more types of mixed gas, the method according to claim 2 for processing the masking layer of the .   The method of claim 2, wherein treating the mask layer further comprises exposing the mask layer to a halogen-containing gas. Processing the mask layer of the _{can, 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 two kinds or more The method of claim 1, further comprising exposing the mask layer to a plasma generated using a mixture of gases. Step, N _2, H _2, CN, or an inert gas, or further comprising the step of exposing the mask layer to the two or more types of mixed gas, the method according to claim 5 for processing the masking layer of the .   6. The method of claim 5, wherein treating the mask layer further comprises exposing the mask layer to an oxygen-containing gas.   The step of processing the mask layer comprises the steps of: generating plasma within the plasma processing system by coupling an AC output to the electrode, another electrode other than the electrode, or a substrate holder, or the two or more. The method of claim 1, comprising exposing the mask layer.   9. The method of claim 8, wherein treating the mask layer comprises exposing the mask layer to a low power plasma generated using a power level of 500W or less.   The method of claim 1, wherein processing the mask layer comprises exposing the mask layer to a plasma generated in a remote plasma source coupled to the plasma processing system.   The method of claim 1, wherein coupling the DC output comprises coupling a DC voltage that is in the range of −2000 volts (V) to 1000V.   2. The method of claim 1, wherein coupling the DC output comprises coupling a DC voltage having a negative polarity and an absolute value greater than or equal to 500V.   The method of claim 1, wherein coupling the DC output comprises coupling the DC output to an upper electrode that is provided on a substrate holder and faces the substrate. 14. The method of claim 13 , wherein generating the plasma comprises coupling a radio frequency (RF) output to the electrode, or another electrode other than the electrode, or a substrate holder, or the two or more. . The step of combining the RF outputs includes:
Coupling a first RF output with the upper electrode at a first RF frequency; and coupling a second RF output with the substrate holder at a second RF frequency that is less than the first RF frequency;
15. The method of claim 14, comprising:   15. The method of claim 14, further comprising modulating the amplitude of the RF output to adjust the spatial distribution of the electron beam bundle of the electron beam.   2. The step of exposing the mask layer to the oxygen-containing plasma or the halogen gas-containing plasma prior to the etching reduces line edge roughness generated in the mask layer during the etching. Method.   The step of processing the mask layer is performed for a predetermined period of time for the patterned mask layer to be resistant to line edge roughness generated in the mask layer during the etching. The method of claim 1.   The method of claim 1, wherein the step of treating the mask layer comprises exposing the mask layer to plasma generated using He, Ne, Ar, Xe, Kr, or a mixture of two or more of these. The method described.   In order to change the mask layer, before the mask layer is processed by exposing the mask layer to oxygen-containing plasma, halogen gas-containing plasma, rare gas-containing plasma, or a mixture of two or more of these. The method according to claim 1, further comprising the step of pretreating the mask layer with a pre-etching electron beam in the absence of halogen atom species. The step of treating the mask layer by exposing the mask layer to an oxygen-containing plasma, a halogen gas-containing plasma, a rare gas-containing plasma, or a mixed plasma of two or more of these:
Coupling a first RF output with a top electrode at a first RF frequency; and coupling a second RF output with the substrate holder at a second RF frequency that is less than the first RF frequency;
And the second RF output is 100 W or less,
The method of claim 1.   The method of claim 21, wherein the second RF power is zero. A method for etching a thin film formed on a substrate and having a mask layer patterned thereon, comprising:
Providing a substrate on a substrate holder in a plasma processing system equipped to generate a plasma and a ballistic electron beam;
Treating the mask layer without generating a ballistic electron beam by exposing the mask layer to an oxygen-containing plasma, a halogen gas-containing plasma, a rare gas-containing plasma, or a mixed plasma of two or more of these. Wherein the step of processing the mask layer is performed without the mask layer being exposed to an electron beam accelerated by direct current (DC) output; and the step of processing the mask layer. Etching the thin film and generating a plasma and a ballistic electron beam in the plasma processing system to transfer the patterned mask layer pattern to the thin film;
Having a method. A plasma processing system equipped to etch a substrate comprising:
Processing chamber;
A gas supply system arranged to supply gas to the processing chamber;
A substrate holder coupled to the processing chamber to process the substrate; and an electrode provided within the processing chamber;
An AC output system coupled to the processing chamber and configured to couple at least one AC signal to the substrate and / or the electrode to generate a plasma within the processing chamber;
A DC output system coupled to the processing chamber and configured to couple a DC voltage to the electrode for generating an electron beam through the plasma;
A control device for controlling the gas supply system, the AC output system, and the DC output system, wherein the gas supply system, the AC output system, and the DC output system are:
A step of treating the mask layer without generating a ballistic electron beam by exposing the mask layer to an oxygen-containing plasma, a halogen gas-containing plasma, a rare gas-containing plasma, or a mixed plasma of two or more of these. And the step of processing the mask layer is performed without the mask layer being exposed to an electron beam accelerated by direct current (DC) power; and
Following the step of processing the mask layer, etching a thin film and generating a plasma and a ballistic electron beam in the plasma processing system to transfer the mask layer pattern to the thin film;
A control device provided to cause
A plasma processing system. A method for etching a thin film having a mask layer formed on a substrate and patterned thereon,
The method is:
Forming a protective layer on the mask layer to protect the mask layer, wherein the step of forming the protective layer comprises exposing the mask layer to an electron beam accelerated by direct current (DC) output. A step that is performed in an untreated state; and a step of etching the thin film to transfer a pattern of the mask layer to the thin film after the formation of the protective layer;
Have
The etching process includes:
Generating plasma from a process gas in a plasma processing system;
Coupling the direct current (DC) output to an electrode in the plasma processing system to generate an electron beam within the plasma processing system to assist the plasma during the etching process; and Exposing to an electron beam;
Having
Method.   26. The method of claim 25, wherein forming the protective layer comprises exposing the substrate to a deposition gas plasma.   27. The method of claim 26, wherein forming the protective layer comprises exposing the mask layer to a hydrocarbon-containing plasma, a fluorocarbon-containing plasma, or a hydrofluorocarbon-containing plasma, or the two or more mixed plasmas. Method. The step of forming the protective layer includes C ₂ H ₄ , CH ₄ , 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 _5. having _{H 8, C 5 H 10,} C 6 H 6, C 6 H 10, or C ₆ H _12, or exposing the mask layer to plasma generated by using a combination of two or more thereof, 27. The method of claim 26. The step of forming the protective layer exposes the mask layer to H ₂ , O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂ , CN, an inert gas, or a mixture of two or more of these. 30. The method of claim 28, further comprising the step of:   27. The method of claim 26, wherein forming the protective layer further comprises immersing the mask layer in alcohol.   27. The method of claim 26, wherein forming the protective layer further comprises immersing the mask layer in ethanol and / or methanol.   The step of forming the protective layer includes plasma generated inside the plasma processing system by coupling an AC output to the electrode, another electrode other than the electrode, a substrate holder, or the two or more. 27. The method of claim 26, further comprising exposing the mask layer to a.   35. The method of claim 32, wherein exposing the mask layer to the plasma further comprises exposing the mask layer to a low power plasma generated using a power level of 500W or less.   27. The method of claim 26, wherein exposing the substrate to a plasma comprises exposing the mask layer to a plasma generated in a remote plasma source that is coupled to the plasma processing system.   26. The method of claim 25, wherein coupling the DC output comprises coupling a DC voltage that is in the range of -2000 volts (V) to 1000V.   2. The method of claim 1, wherein coupling the DC output comprises coupling a DC voltage having a negative polarity and an absolute value greater than or equal to 500V.   26. The method of claim 25, wherein coupling the DC output comprises coupling the DC output to an upper electrode that is provided on a substrate holder and faces the substrate.   38. The method of claim 37, wherein generating the plasma comprises coupling a radio frequency (RF) output to the electrode, or another electrode other than the electrode, or a substrate holder, or the two or more. . The step of combining the RF outputs includes:
Coupling a first RF output with the upper electrode at a first RF frequency; and coupling a second RF output with the substrate holder at a second RF frequency that is less than the first RF frequency;
40. The method of claim 38, comprising:   39. The method of claim 38, further comprising modulating the amplitude of the RF output to adjust the spatial distribution of the electron beam bundle of the electron beam.   The step of forming the protective layer is performed for a predetermined period of time for the patterned mask layer to be resistant to line edge roughness generated in the mask layer during the etching. 26. The method of claim 25. The step of forming the protective layer by exposing the mask layer to oxygen-containing plasma, halogen gas-containing plasma, rare gas-containing plasma, or a mixed plasma of two or more of these:
Coupling a first RF output with a top electrode at a first RF frequency; and coupling a second RF output with the substrate holder at a second RF frequency that is less than the first RF frequency;
And the second RF output is 100 W or less,
26. The method of claim 25.   43. The method of claim 42, wherein the second RF power is zero. A method for etching a thin film having a mask layer formed on a substrate and patterned thereon,
The method is:
Forming on the patterned mask layer a protective layer having a predetermined thickness provided to protect the mask layer during a ballistic electron beam assisted plasma etching process, the protective layer comprising: Forming the mask layer is performed without being exposed to an electron beam accelerated by direct current (DC) output; and, following the step of forming the protective layer, etching the thin film; and Performing the ballistic electron beam assisted plasma etching on the substrate to transfer the patterned mask layer pattern to the thin film;
Have
The predetermined thickness is in the range of 1 nm to 200 nm;
Method.   45. The method of claim 44, wherein the predetermined thickness is in the range of 50 nm to 100 nm. A plasma processing system equipped to etch a substrate, comprising:
The plasma processing system is:
Processing chamber;
A gas supply system arranged to supply gas to the processing chamber;
A substrate holder configured to couple with the processing chamber to process the substrate;
Electrodes provided inside the processing chamber;
Have
An AC output system is provided to couple with the processing chamber and to generate at least one AC signal to the substrate and / or the electrode to generate plasma within the processing chamber;
A DC output system is provided to couple to the processing chamber and to couple a DC voltage to the electrode to generate an electron beam through the plasma;
A control device for controlling the gas supply system, the AC output system, and the DC output system, wherein the gas supply system, the AC output system, and the DC output system are:
Forming a protective layer on the mask layer to protect the mask layer; and
Subsequent to forming the protective layer, etching the thin film and generating a plasma and ballistic electron beam in the plasma processing system to transfer the patterned mask layer pattern to the thin film. ;
To execute,
Plasma processing system. A method for etching a thin film having a mask layer formed on a substrate and patterned thereon,
The method is:
Forming a pattern on the mask layer;
A pre-etched electron beam generated by coupling a direct current (DC) output having a negative polarity in the plasma to an electrode in a plasma processing system in the absence of halogen atom species to change the mask layer Processing the patterned mask layer by: and after processing the patterned mask layer, etching the thin film in the plasma processing system to transfer the pattern of the mask layer to the thin film;
Have
The etching process includes:
Generating an etching plasma from an etching gas;
Coupling a direct current (DC) output to an electrode in the plasma processing system to generate a second ballistic electron beam within the plasma processing system that supports the etching plasma during the etching process; and Exposing to the etching plasma and the second ballistic electron beam;
Having
Method. The step of treating the mask layer with the pre-etched electron beam comprises:
Providing the substrate in the plasma processing system; and processing the mask layer using an electron beam source coupled to the plasma processing system;
48. The method of claim 47, comprising: The step of treating the mask layer with the pre-etched electron beam comprises:
Providing the substrate in a substrate processing system other than the plasma processing system; and processing the mask layer using an electron beam source coupled to the plasma processing system;
48. The method of claim 47, comprising: The step of treating the mask layer with the pre-etched electron beam comprises:
Providing the substrate on a substrate holder within the plasma processing system;
Generating a pre-etch plasma in the plasma processing system from a pre-etch gas;
Coupling a DC output to an electrode within the plasma processing system to generate the pre-etch electron beam; and exposing the substrate to the pre-etch plasma and the pre-etch electron beam;
Having
48. The method of claim 47.   51. The method of claim 50, wherein generating the pre-etch plasma comprises generating the pre-etch plasma from one or more noble gases. 51. The method of claim 50, wherein generating the pre-etch plasma comprises generating the pre-etch plasma from a mixture of one or more rare gases and CHF ₃ .   51. The method of claim 50, wherein generating the pre-etch electron beam comprises coupling a DC output to an upper electrode facing the substrate on the substrate holder.   51. The method of claim 50, wherein generating the pre-etch electron beam comprises combining a DC voltage having a negative polarity and an absolute value of 500V or greater.   The step of generating the pre-etching electron beam couples a high frequency (RF) output having a total output of 500 W or less to the electrode, another electrode other than the electrode, or a substrate holder, or the two or more. 51. The method of claim 50, comprising a step.   51. The method of claim 50, wherein generating the pre-etch electron beam comprises coupling a DC voltage that is in the range of -2000 volts (V) to 1000V. 48. The method of claim 47, wherein generating the second ballistic electron beam comprises combining a DC voltage having a negative polarity and an absolute value of 500V or greater. 48. The method of claim 47, wherein generating the second ballistic electron beam comprises coupling a DC output to an upper electrode provided on a substrate holder and facing the substrate. The step of generating the second ballistic electron beam comprises coupling a radio frequency (RF) output to the electrode, another electrode other than the electrode, or a substrate holder, or the two or more. The method described. The step of combining the RF outputs includes:
Coupling a first RF output with the upper electrode at a first RF frequency; and coupling a second RF output with the substrate holder at a second RF frequency that is less than the first RF frequency;
60. The method of claim 59, comprising:   60. The method of claim 59, further comprising modulating the amplitude of the RF output to adjust the spatial distribution of the electron beam bundle of the electron beam.   48. The method of claim 47, wherein treating the mask layer with a pre-etch electron beam prior to the etching step reduces line edge roughness created in the mask layer during the etching.   The step of processing the mask layer is performed for a predetermined period of time for the patterned mask layer to be resistant to line edge roughness generated in the mask layer during the etching. 48. The method of claim 47. 48. The method of claim 47, wherein an electron beam energy of the pre-etch electron beam is less than an electron beam energy of the second ballistic electron beam.   48. The method of claim 47, wherein the electron beam energy of the pre-etch electron beam increases stepwise or at a constant rate during processing of the mask layer with the pre-etch electron beam. A method of etching a thin film on a substrate using a plasma processing system having a ballistic electron beam and a plasma comprising:
Forming a mask layer having a pattern on the thin film;
Generating a first ballistic electron beam in the absence of a halogen atom species by coupling a direct current (DC) output having negative polarity in the plasma to an electrode;
Treating the mask layer by exposing a substrate having the mask layer to the first ballistic electron beam;
Generating an etching plasma from an etching gas in the plasma processing system;
Generating a second ballistic electron beam in the plasma processing system by coupling a direct current (DC) output having a negative polarity in the plasma to an electrode; and for transferring the pattern to the thin film, Exposing the substrate to an etching plasma and the second ballistic electron beam;
Having a method. A plasma processing system equipped to etch a thin film having a mask layer on a substrate, comprising:
The plasma processing system is:
Processing chamber;
A gas supply system arranged to supply gas to the processing chamber;
A substrate holder configured to couple with the processing chamber to process the substrate;
Electrodes provided inside the processing chamber;
Have
An AC output system is provided to couple with the processing chamber and to generate at least one AC signal to the substrate and / or the electrode to generate plasma within the processing chamber;
A DC output system is provided to couple to the processing chamber and to couple a DC voltage to the electrode to generate an electron beam through the plasma;
A control device for controlling the gas supply system, the AC output system, and the DC output system, wherein the gas supply system, the AC output system, and the DC output system are:
Forming a pattern on the mask layer;
In order to change the mask layer on which the pattern is formed, before etching is generated by coupling a direct current (DC) output having a negative polarity in the plasma to the electrode in the absence of halogen atom species. Treating the mask layer on which the pattern is formed with an electron beam; and
Following the step of processing the mask layer, plasma and a ballistic electron beam are applied into the plasma processing system to etch the thin film and transfer the pattern of the mask layer formed with the pattern to the thin film. Generating step;
To execute,
Plasma processing system.

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