High Selectivity Isotropic Dry Etching Process Using Remote Pulsed Plasma

Abstract

One embodiment of the present invention comprises the steps of: supplying a remote plasma source; applying RF power to the remote plasma source to form a remote plasma; and selectively etching only the etching target among the process targets through the formed remote plasma. A high-selectivity isotropic dry etching process for a remote pulsed plasma is provided, characterized in that, in the step of forming the remote plasma, the applied RF power is in the form of pulsed RF power.

Description

Technology Field

[0001] The present invention relates to a high-selectivity isotropic dry etching process using remote pulse plasma, and more specifically, to a high-selectivity isotropic dry etching process using remote pulse plasma that can be applied to 3D DRAM or GAA structures. Background Technology

[0002] In the case of conventional wet etching applied to form 3D DRAM or GAA structures, selective etching of SiGe is possible using a chemistry of HF, an oxidizing agent, and other acids. However, due to the surface tension of the solution, problems such as failure to etch deep inside patterns in high aspect ratios and fine patterns, pattern leaning, and collapse may occur, so it was necessary to develop a dry etching process.

[0003] In the conventional gas etching method among the isotropic dry etching processes developed accordingly, toxic gases such as HCl, ClF3, F2, and HF are used, and there are limitations in process optimization due to the need for a high-temperature process or limited parameters (flow rate, pressure, temperature).

[0004] In addition, in conventional plasma etching processes, etching was performed using F radicals formed using CF4, NF3, etc.

[0005] At this time, while SiGe can be etched more selectively using F2 molecules, which are toxic gases, compared to the aforementioned F radical, due to the difference in activation energy, etching using the F2 gas presents the problem of toxicity in the F2 gas as described above; therefore, it is necessary to develop a process to resolve this issue. Prior art literature

[0006] Republic of Korea Registered Patent No. 1884510 B1 The problem to be solved

[0007] The technical problem that the present invention aims to solve is to provide a high-selectivity isotropic dry etching process of remote pulsed plasma that can be applied to 3D DRAM or GAA structures.

[0009] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0010] To achieve the above technical objectives, one embodiment of the present invention provides a high-selectivity isotropic dry etching process using remote pulse plasma.

[0011] A high-selectivity isotropic dry etching process of the remote pulse plasma according to one embodiment of the present invention is,

[0012] The method comprises the steps of: supplying a remote plasma source; applying RF power to the remote plasma source to form a remote plasma; and selectively etching only the etching target among the process targets through the formed remote plasma.

[0013] In the step of forming the remote plasma, the applied RF power is characterized as being in the form of pulsed RF power, and the process may be a high-selectivity isotropic dry etching process of a remote pulsed plasma.

[0014] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that the step of forming the remote plasma by applying pulsed RF power is performed repeatedly with an RF power high-state section and a low-state section as one cycle.

[0015] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of a remote pulse plasma, characterized in that a radical species is primarily formed from the remote plasma source in the RF power high-state section, and a secondary gas species is formed by partially recombining the formed radical species in the low-state section.

[0016] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of remote pulse plasma, characterized in that the secondary forming gas species has higher etching selectivity for the etching target than the radical species.

[0017] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of a remote pulse plasma, characterized by further including: a step of selectively etching only the etching target among the process targets by passing the formed remote plasma through a grid plate to deliver the formed radical species and secondary formed gas species; and a step of cooling the etched process target to maintain the thermal stability of the process.

[0018] In addition, according to one embodiment of the present invention, the step of forming the remote plasma by applying pulsed RF power may include a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that the time ratio (duty ratio) of the RF power high-state section is 3% to 75% for the entire section.

[0019] In addition, according to one embodiment of the present invention, the step of forming the remote plasma by applying pulsed RF power may include a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that the duty ratio of the RF power high-state section is 15% to 50% of the total section.

[0020] In addition, according to one embodiment of the present invention, the target for performing the process has a structure in which Si layers and SiGe layers are alternately stacked, and among the stacked Si layers and SiGe layers, only the SiGe layer is targeted for etching and selectively etched, thereby providing a high-selectivity isotropic dry etching process of remote pulse plasma.

[0021] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of remote pulsed plasma, characterized in that the remote plasma source is a gas containing a fluoride compound and provides F radicals.

[0022] In addition, according to one embodiment of the present invention, there may be a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that the fluorinated compound is a gas comprising one or more selected from the group consisting of NF₃, SF6, HFCs, PFCs, PF3, PF5, BF3, ClF3, ClF, IF5, and IF7.

[0023] In addition, according to one embodiment of the present invention, the step of forming the remote plasma by applying pulsed RF power is performed repeatedly with an RF power high-state section and a low-state section as one cycle.

[0024] There may be a high-selectivity isotropic dry etching process of remote pulsed plasma, characterized in that F radicals are primarily formed from a gas containing NF₃ in the RF power high-state region, and F₂ molecules are formed by the partial recombination of the formed F radicals in the low-state region. Effects of the invention

[0026] According to one embodiment of the present invention, a high-selectivity isotropic dry etching process of remote pulse plasma applicable to 3D DRAM or GAA structures can be provided.

[0027] According to one embodiment of the present invention, in an isotropic dry etching process using a remote plasma, by applying pulsed RF power to a remote plasma source, a radical species and a secondary gas species formed by the recombination of a portion of the radical species are formed, thereby improving etching characteristics.

[0029] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims. Brief explanation of the drawing

[0030] Figure 1 is a schematic diagram briefly illustrating the fabrication process of a GAA-FET and a 3D DRAM, which includes a process of selectively etching only the SiGe layer in an epitaxy Si-SiGe stack structure. FIG. 2 is a schematic diagram illustrating problems such as pattern leaning that may occur when using a conventional wet process. FIG. 3 is a schematic diagram illustrating a mechanism (a) in which only radical species are formed when RF power is continuously applied to a remote plasma source, and a mechanism (b) in which radical species and a secondary gas species formed by the recombination of some of the radical species are formed when pulsed RF power is applied to a remote plasma source. FIG. 4 is a schematic diagram illustrating a comparison of etching profiles when performing a high-selectivity isotropic dry etching process of a remote pulse plasma according to one embodiment of the present invention and when RF power is continuously applied to a remote plasma source (CW etching). FIG. 5 is an exemplary diagram showing a system capable of performing a high-selectivity isotropic dry etching process of a remote pulse plasma according to one embodiment of the present invention. FIG. 6 is a graph showing the etching rate and etching selectivity of SiGe according to pulse duty when performing a high-selectivity isotropic dry etching process of remote pulse plasma according to one embodiment of the present invention. FIG. 7 is an SEM image showing the actual etching profile of SiGe according to pulse duty when performing a high-selectivity isotropic dry etching process of remote pulse plasma according to one embodiment of the present invention. Specific details for implementing the invention

[0031] The present invention will be described below with reference to the attached drawings. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein, and should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0032] In addition, to clearly explain the invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0033] Throughout the specification, when it is stated that a part is "connected (connected, in contact, joined)" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members in between.

[0034] Furthermore, when a part such as a layer, film, region, or plate is described as being “on” another part, this includes not only cases where it is “immediately above” the other part, but also cases where there is another part in between. Additionally, in this specification, when a part such as a layer, film, region, or plate is described as being formed “on” another part, the direction in which it is formed is not limited to the upward direction only, but includes cases where it is formed in the lateral or downward direction. Conversely, when a part such as a layer, film, region, or plate is described as being “below” another part, this includes not only cases where it is “immediately below” the other part, but also cases where there is another part in between.

[0035] In this specification, "upper surface" and "lower surface" are used as relative concepts to facilitate understanding of the technical concept of the present invention. Accordingly, "upper surface" and "lower surface" do not refer to specific directions, locations, or components, but are interchangeable.

[0036] For example, 'upper surface' may be interpreted as 'lower surface,' and 'lower surface' may be interpreted as 'upper surface.' Therefore, 'upper surface' may be expressed as 'No. 1' and 'lower surface' as 'No. 2,' or 'lower surface' may be expressed as 'No. 1' and 'upper surface' as 'No. 2.' However, within a single embodiment, 'upper surface' and 'lower surface' are not used interchangeably.

[0037] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0038] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0039] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0041] Figure 1 is a schematic diagram briefly illustrating the fabrication process of a GAA-FET and a 3D DRAM, which includes a process of selectively etching only the SiGe layer in an epitaxy Si-SiGe stack structure.

[0042] FIG. 2 is a schematic diagram illustrating problems such as pattern leaning that may occur when using a conventional wet process.

[0043] FIG. 3 is a schematic diagram illustrating a mechanism (a) in which only radical species are formed when RF power is continuously applied to a remote plasma source, and a mechanism (b) in which radical species and a secondary gas species formed by the recombination of some of the radical species are formed when pulsed RF power is applied to a remote plasma source.

[0044] FIG. 4 is a schematic diagram illustrating a comparison of etching profiles when performing a high-selectivity isotropic dry etching process of a remote pulse plasma according to one embodiment of the present invention and when RF power is continuously applied to a remote plasma source (CW etching).

[0045] FIG. 5 is an exemplary diagram showing a system capable of performing a high-selectivity isotropic dry etching process of a remote pulse plasma according to one embodiment of the present invention.

[0047] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0048] A high-selectivity isotropic dry etching process using remote pulse plasma according to one embodiment of the present invention is described.

[0050] As an example of the above embodiment, the method comprises: a step of supplying a remote plasma source; a step of forming a remote plasma by applying RF power to the remote plasma source; and a step of selectively etching only the etching target among the process targets through the formed remote plasma; wherein

[0051] There may be a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that, in the step of forming the remote plasma, the applied RF power is in the form of pulsed RF power.

[0053] Referring to Fig. 1, it can be seen that in the process of fabricating GAA-FETs and 3D DRAMs, a process of selectively etching only the SiGe layer in an Epitaxy Si-SiGe stack structure is essential.

[0054] Conventionally, a wet process was performed to selectively etch only the SiGe layer. In this wet process, a mixed solution of an oxidizing agent (CH3COOH, HNO3, H2O2, etc.) and a SiO2 etchant (HF, NH4F, etc.) was mainly used, or this was used repeatedly in sequence.

[0055] At this time, referring to FIG. 2, it can be seen that problems such as etching the bottom of a high aspect ratio pattern or pattern leaning occur due to the surface tension of the solvent used in the wet process.

[0057] Accordingly, a gas process was developed during the dry process; however, while this gas process has the advantage of easy process control, it has the problem that high-temperature processes and the use of toxic gases (HCl, ClF3, F2HF, etc.) are essential.

[0059] Due to the above problem, a plasma process was developed during the dry process to avoid the use of toxic gases such as HCl, ClF3, and F2HF.

[0060] The above plasma process primarily utilizes F-based plasma and is a selective etching process based on the difference in bonding energy between Si and Ge-related compounds.

[0061] In the above process, a surface oxide film is formed using the difference in oxidation rate, and then an oxide etching process is applied to achieve selective etching.

[0062] However, the above process had a limitation in that it was difficult to control the chemistry compared to the conventional wet etching process. Therefore, there was a need to develop a new process to secure high selectivity and an etching profile.

[0064] In the case of the present invention, in the step of forming the remote plasma, the applied RF power is characterized as being in the form of pulsed RF power.

[0065] At this time, the step of forming the remote plasma by applying pulse-shaped RF power can be performed repeatedly with an RF power high-state period and a low-state period as one cycle.

[0066] Referring to Fig. 3, an RF power application period indicated as RF On; and a rest period indicated as RF Off can be seen.

[0068] The number of repetitions mentioned above can be appropriately modified depending on the environment, such as the degree of etching to be performed and the etching target.

[0069] At this time, the above RF power high-state section may be characterized by the primary formation of radical species from the remote plasma source, and the low-state section in which the formed radical species partially recombine to form secondary gas species.

[0070] The mechanism described above can be confirmed through Fig. 3 above.

[0072] In addition, the above secondary formed gas species may be characterized by having higher etching selectivity for the etching target than the above radical species.

[0074] As described above, when a portion of the radical species recombines to synthesize a secondary formed gas species, in addition to the radical species, the secondary formed gas species can also be used for etching.

[0075] Therefore, if the secondary forming gas species has higher etching selectivity for the etching target than the radical species, the etching efficiency and etching selectivity may be higher when etching is performed together with the radical species and the secondary forming gas species, as in the example of the above embodiment, compared to when etching is performed only with a simple radical species as in the conventional method.

[0077] Referring to FIG. 4, the process target (Reference) is a structure in which Si layers and SiGe layers are alternately stacked, and

[0078] You can see a schematic diagram showing the etching profile when the above process target (Reference) is etched by CW (Continuous Wave) etching and the etching profile when pulse etching is performed as in the above embodiment of the present invention.

[0080] As in the above example, when pulse etching the reference material, it can be confirmed that only the SiGe layer, which is the target etching material among the reference materials, is etched with high selectivity, and the Si layer that is not the target material remains intact without damage.

[0081] On the other hand, when the above process target (Reference) is Continuous Wave (CW) etched, it can be confirmed that the etching selectivity is lower because the etching (loss) proceeds to the end of the Si layer, which is an untargeted target among the above process targets (Reference).

[0083] As an example of the above embodiment, there may be a high-selectivity isotropic dry etching process of a remote pulse plasma, further comprising: a step of selectively etching only the etching target among the process targets by passing the formed remote plasma through a grid plate to deliver the formed radical species and secondary formed gas species; and a step of cooling the etched process target to maintain the thermal stability of the process.

[0085] Referring to FIG. 5, as an example of a system in which the above process is performed, a schematic diagram can be seen of the step of discharging NF3 / He to a remote-type ICP source through pulsed RF power, and then passing the formed remote plasma through a grid to deliver the formed radical species and secondary formed gas species to a process target, thereby selectively etching only the etching target among the process targets; and the step of cooling the etched process target to maintain the thermal stability of the process.

[0087] As an example of the above embodiment, the step of forming the remote plasma by applying pulsed RF power may include a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that the duty ratio of the RF power high-state section occupies 3% to 75% of the entire section.

[0089] As described above, if the duty ratio of the RF power high-state section is maintained at less than 3% for the entire section, there may be a problem in that sufficient decomposition of F-based gases does not occur, leading to recombination into F2 or the formation of too little etchant participating in the process.

[0090] Conversely, if the duty ratio of the RF power high-state section is maintained for too long, exceeding 75% for the entire section, there may be a problem in that the F radical generated through discharge is not sufficient to recombine into F2, making it difficult to expect the effect of pulsed plasma to participate in F radical etching.

[0092] More preferably, as an example of the above embodiment, the step of forming the remote plasma by applying pulsed RF power may include a high-selectivity isotropic dry etching process of a remote pulsed plasma, characterized in that, for the entire section, the time ratio (duty ratio) of the RF power high-state section is 15% to 50%.

[0093] Most preferably, as an example of the above embodiment, the step of forming the remote plasma by applying pulsed RF power may be characterized in that, for the entire section, the time ratio (duty ratio) of the RF power high-state section is 15% to 30%, and there may be a high-selectivity isotropic dry etching process of the remote pulsed plasma.

[0095] For the entire section, if the duty ratio occupied by the RF power application section is 100%, it becomes the same as conventional CW (Continuous Wave) etching, and

[0096] As can be seen in the following experimental examples and Figure 6,

[0097] For the entire section, it can be observed that the etching rate and etching selectivity change significantly when the duty ratio of the RF power high-state section falls below 50%.

[0098] For the entire section, it can be confirmed that the highest value in terms of etching selectivity is obtained when the duty ratio of the RF power high-state section is in the range of 15% to 30%.

[0100] In this specification, throughout, the high-state and low-state each refer to a relatively high power state and a low power state, respectively, rather than referring only to a state where the RF power is completely turned on or off.

[0101] In other words, it is a concept that encompasses not only the state where RF power is completely turned on or off, but also all conditions distinguished by relatively high power states and low power states.

[0103] As an example of the above embodiment, the target for performing the process has a structure in which Si layers and SiGe layers are alternately stacked.

[0104] There may be a high-selectivity isotropic dry etching process of remote pulse plasma, characterized by selectively etching only the SiGe layer among the stacked Si layer and SiGe layer.

[0106] In addition, there may be a high-selectivity isotropic dry etching process of remote pulsed plasma, characterized in that the remote plasma source is a gas containing a fluoride compound and provides F radicals.

[0107] At this time, the fluorinated compound may be a gas comprising one or more selected from the group consisting of F-based gases such as NF₃, SF6, HFCs, PFCs, PF3, PF5, BF3, ClF3, ClF, IF5, and IF7.

[0108] In addition, the gas containing the above fluorinated compound may further include inert carrier gases such as He, Ar, Kr, N2, etc. or addictive gases that promote the dissociation of Cl2, NO, O2, H2, etc. or cause additional chemical reactions.

[0110] As an example of the above embodiment, the step of forming the remote plasma by applying pulsed RF power is performed repeatedly with an RF power high-state section and a low-state section as one cycle.

[0111] There may be a high-selectivity isotropic dry etching process of remote pulsed plasma, characterized in that F radicals are primarily formed from a gas containing NF₃ in the RF power high-state region, and F₂ molecules are formed by the partial recombination of the formed F radicals in the low-state region.

[0113] As described above, in the case of an embodiment in which only the SiGe layer is targeted for etching among a structure in which Si layers and SiGe layers are alternately stacked,

[0114] This is an etching method that can increase the etch selectivity and etch rate of SiGe relative to Si by applying pulsed RF power to a plasma source to form F2 which is more selective for SiGe relative to F, and which can be applied to 3D DRAM or GAA structures as a selective plasma etching process for SiGe relative to Si.

[0115] The above SiGe forms relatively weak bonding compared to Si, and SiGe is etched primarily through this difference in bonding energy.

[0117] Unlike conventional methods that directly supply toxic F₂ gas, the above embodiment of the present invention uses a method of instantaneously generating F₂ within the plasma by applying pulsed RF power using a plasma source based on a less toxic fluoride compound, thereby not only ensuring process stability but also improving process selectivity.

[0118] More specifically, the above embodiment of the present invention first utilizes a plasma source based on a low-toxicity fluoride compound.

[0119] The above-mentioned low-toxicity fluoride compound is a gas that can be handled relatively safely, and when applied to a plasma process, it can generate F radicals and a small amount of F₂ molecules as needed.

[0120] In addition, since the toxic gas F₂ is generated directly within the plasma, the risk of toxicity is lower and management is easier compared to handling F₂ gas directly.

[0121] At this time, since the NF₃ plasma instantly generates an appropriate amount of F₂, it can be controlled so that only the amount of F₂ required for the process is generated.

[0123] In addition, in the above embodiment of the present invention, F₂ generation can also be controlled through Pulsed RF Power.

[0124] By using the pulsed RF power mentioned above, the time at which F radicals recombine into F₂ can be controlled. In other words, F₂ is generated only when necessary, and the accumulation of unnecessary toxic gases can be reduced.

[0125] In the above embodiment, since F₂ is generated in a limited pulse form rather than a continuous supply of F₂, selective etching of SiGe can be improved while maintaining a stable low F₂ concentration.

[0126] Unlike the case where F₂ is supplied directly from the outside in gaseous form, this method generates it within the process for a limited time, which can reduce toxicity issues.

[0128] In other words, since the toxic gas F₂ is generated only when necessary and disappears quickly after use, it differs from situations where high concentrations of F₂ gas are continuously exposed to the process; consequently, this enables the effective implementation of selective etching of SiGe against Si while minimizing the toxicity issues associated with F₂.

[0130] Experimental Example 1. Analysis of etching characteristics according to pulse duty.

[0132] Experimental Example 1 above is explained with reference to Figs. 6 and 7.

[0134] FIG. 6 is a graph showing the etching rate and etching selectivity of SiGe according to pulse duty when performing a high-selectivity isotropic dry etching process of remote pulse plasma according to one embodiment of the present invention.

[0135] Referring to FIG. 6, it can be seen that for the entire section, as the duty ratio of the RF power application section decreases from 100%, the etching rate for SiGe increases and the etching rate for Si decreases.

[0136] Accordingly, it can be confirmed that the SiGe etching selectivity of the above etching process for Si and SiGe increases.

[0137] In other words, it can be confirmed that a higher SiGe etching selectivity can be obtained simply by introducing pulsed plasma, thereby enabling more precise selective etching.

[0138] Furthermore, when the above Duty Ratio enters a range of less than 50%, it can be observed that the etching rate for SiGe increases significantly and the etching rate for Si decreases significantly, and

[0139] Accordingly, it can be confirmed that the SiGe etching selectivity of the above etching process for Si and SiGe increases significantly.

[0141] In addition, when entering a range where the above Duty Ratio is less than 30%, although the etching rate for SiGe decreases, the etching rate for Si continues to decrease, thereby enabling an etching process with less Si loss.

[0142] Within the above range, it can be confirmed that the SiGe etching selectivity of the above etching process for Si and SiGe is the highest.

[0144] FIG. 7 is an SEM image showing the actual etching profile of SiGe according to pulse duty when performing a high-selectivity isotropic dry etching process of remote pulse plasma according to one embodiment of the present invention.

[0145] Referring to Fig. 7, it can be seen that Si loss decreases as the pulse duty ratio decreases. In addition, among the pulse duty ratios ranging from 15% to 30%, it can be seen that the best etching profile is found around 15%.

[0147] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0148] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A high-selectivity isotropic dry etching process of a remote pulse plasma, comprising: a step of supplying a remote plasma source; a step of forming a remote plasma by applying RF power to the remote plasma source; and a step of selectively etching only the etching target among the process targets through the formed remote plasma; wherein the process target has a structure in which Si layers and SiGe layers are alternately stacked, and among the stacked Si layers and SiGe layers, only the SiGe layer is targeted for etching and selectively etched, and wherein, in the step of forming the remote plasma, the applied RF power is in the form of pulsed RF power. Claim 2 A high-selectivity isotropic dry etching process of a remote pulsed plasma according to claim 1, wherein the step of forming the remote plasma by applying pulsed RF power is characterized by being performed repeatedly with an RF power high-state section and a low-state section as one cycle. Claim 3 A high-selectivity isotropic dry etching process of a remote pulse plasma according to claim 2, characterized in that a radical species is primarily formed from the remote plasma source in the RF power high-state section, and a secondary gas species is formed by the partial recombination of the formed radical species in the low-state section. Claim 4 A high-selectivity isotropic dry etching process of remote pulse plasma, characterized in that, in paragraph 3, the secondary forming gas species has higher etching selectivity toward the etching target than the radical species. Claim 5 A high-selectivity isotropic dry etching process of a remote pulse plasma, characterized in that, in claim 3, the remote plasma formed above is passed through a grid plate to deliver the formed radical species and secondary formed gas species to selectively etch only the etching target among the process targets; and the etched process target is cooled to maintain the thermal stability of the process. Claim 6 A high-selectivity isotropic dry etching process of a remote pulsed plasma, wherein, in paragraph 2, the step of forming the remote plasma by applying pulsed RF power is characterized in that, for the entire section, the time ratio (duty ratio) occupied by the RF power high-state section is 3% to 75%. Claim 7 A high-selectivity isotropic dry etching process of a remote pulse plasma, wherein, in paragraph 2, the step of forming the remote plasma by applying pulse-shaped RF power is characterized in that, for the entire section, the time ratio (duty ratio) occupied by the RF power high-state section is 15% to 50%. Claim 8 delete Claim 9 A high-selectivity isotropic dry etching process of remote pulsed plasma according to claim 1, wherein the remote plasma source is a gas containing a fluoride compound and provides F radicals. Claim 10 A high-selectivity isotropic dry etching process of remote pulsed plasma, characterized in that, in claim 9, the fluorinated compound is a gas comprising one or more selected from the group consisting of NF₃, SF6, HFCs, PFCs, PF3, PF5, BF3, ClF3, ClF, IF5, and IF7. Claim 11 A high-selectivity isotropic dry etching process of a remote pulsed plasma according to claim 10, wherein the step of forming the remote plasma by applying pulsed RF power is performed repeatedly with an RF power high-state section and a low-state section as one cycle, wherein F radicals are primarily formed from a gas containing NF₃ in the RF power high-state section, and F₂ molecules are formed by the partial recombination of the formed F radicals in the low-state section.

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