Substrate processing method

Abstract

A substrate processing method for preventing damage to a lower patterned structure includes: forming a first thin film having a certain thickness by repeatedly performing a first cycle that includes supplying a first reactant to the structure and purging residues; and forming a second thin film by changing the chemical composition of the first thin film having a certain thickness.

Description

Technical Field

[0001] One or more embodiments relate to a substrate processing method, and more particularly, to a substrate processing method for patterning a structure formed on a substrate. Background Art

[0002] When depositing a thin film on a patterned structure on a substrate using plasma, the patterned structure may be damaged by radical active species. For example, in the case of a patterned structure such as a spin-on hard mask (SOH) including a polymer material, damage to the SOH film may occur. More specifically, when depositing a thin film on a substrate on which an SOH film is formed using oxygen, oxygen radical active species are generated by plasma application, and the SOH film under the thin film reacts with the oxygen radicals, thereby changing the film quality or causing physical damage to the SOH film. Due to the damage to the lower patterned structure, the pitch between patterns may not be constant in subsequent patterning processes. Summary of the Invention

[0003] One or more embodiments include a method for improving the CD uniformity of a patterning process by preventing damage to a lower patterned structure.

[0004] Additional aspects will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the proposed embodiments of the present disclosure.

[0005] According to one or more embodiments, a substrate processing method includes: forming a first thin film having a certain thickness by repeatedly performing a first cycle that includes supplying a first reactant to a structure and purging residues; and forming a second thin film by changing the chemical composition of the first thin film having a certain thickness.

[0006] According to an example of the substrate processing method, the first reactant may include a silicon-containing source gas.

[0007] According to another example of the substrate processing method, plasma may be applied during at least a part of the first cycle, and the first reactant may be dissociated by the plasma to adsorb the first thin film on the structure.

[0008] According to another example of the substrate processing method, during the first cycle, a second reactant that does not react with the structure is supplied, and the first thin film may be densified by the second reactant.

[0009] According to another example of the substrate processing method, during the formation of the second thin film, a second cycle is repeatedly performed, and the second cycle may include: supplying a third reactant on the first thin film having a certain thickness; applying plasma to cause a reaction between the first thin film and the third reactant; and purging residues.

[0010] According to another example of the substrate processing method, the third reactant includes oxygen, and during the reaction induction, the first thin film can be oxidized.

[0011] According to another example of the substrate processing method, the third reactant can react with the structure.

[0012] According to another example of the substrate processing method, the thickness of the first thin film can be greater than or equal to a certain thickness, and this thickness allows the loss of the structure that occurs when the third reactant reacts with the first thin film to be less than a certain value.

[0013] According to another example of the substrate processing method, this certain thickness can be at least 15 angstroms.

[0014] According to another example of the substrate processing method, the residues purged during the second cycle can include at least one of CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2.

[0015] According to another example of the substrate processing method, the first thin film includes a mixture of elements that make up the first reactant, and the first thin film is formed by adsorbing the mixture on the structure.

[0016] According to another example of the substrate processing method, the first thin film can include chemical bonds formed by the reaction of one element in the mixture with at least one element that makes up the structure.

[0017] According to another example of the substrate processing method, the substrate processing method can further include: removing at least a part of the second thin film to form a spacer pattern for the structure; removing the structure; and patterning the underlying structure using the spacer pattern as a mask.

[0018] According to another example of the substrate processing method, the spacer pattern can include a first protrusion, a second protrusion, and a third protrusion protruding from the underlying structure, and the difference between the first distance between the first protrusion and the second protrusion and the second distance between the second protrusion and the third protrusion can be less than 5 angstroms.

[0019] According to another example of the substrate processing method, the substrate processing method can further include: forming a third thin film having the same composition as the second thin film on the second thin film.

[0020] According to another example of the substrate processing method, the substrate processing method can further include: exposing the structure by performing etch-back on the second thin film and the third thin film; removing the structure; and patterning the underlying structure using the remaining parts of the second thin film and the third thin film as a mask.

[0021] According to another example of the substrate processing method, during the formation of the third thin film, the third cycle is performed multiple times, where the third cycle may include: supplying a first reactant on the second thin film; purging the residue of the first reactant; supplying a third reactant in a plasma atmosphere; and purging the residue of the third reactant.

[0022] According to one or more embodiments, a substrate processing method includes: forming a first thin film by supplying a first reactant and a second reactant on a substrate having a patterned structure; supplying a third reactant; and converting the first thin film into a second thin film.

[0023] According to an example of the substrate processing method, the substrate processing method may further include: forming a third thin film on the second thin film by supplying a first reactant and a third reactant.

[0024] According to one or more embodiments, a substrate processing method includes: forming a first thin film with a certain thickness adsorbed on a patterned spin-on hard mask (SOH) structure by performing a first cycle multiple times, the first cycle including supplying a silicon source gas on the patterned SOH structure and purging the residue; forming a second thin film by changing the chemical composition of the first thin film by performing a second cycle multiple times, the second cycle including supplying a reaction gas that reacts with the patterned SOH structure and with the silicon source gas and purging the residue; and forming a third thin film having the same composition as the second thin film on the second thin film by performing a third cycle multiple times, the third cycle including supplying a silicon source gas and supplying a reaction gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings, where:

[0026] Figures 1 to 6 is a cross-sectional view showing a method of manufacturing a semiconductor device according to an embodiment;

[0027] Figures 7 to 10 is a diagram showing a substrate processing method according to an embodiment;

[0028] Figure 11 is a diagram showing damage to the underlying SOH film and related problems caused by oxygen radicals during the deposition of a SiO2 film by supplying oxygen radicals on a patterned structure during a patterning process;

[0029] Figure 12 is a flowchart showing a method capable of minimizing the loss or deformation of a lower film when depositing a thin film using active radicals on a patterned structure;

[0030] Figure 13 is a diagram showing a substrate processing method according to an embodiment;

[0031] Figure 14 is a flowchart of a substrate processing method according to an embodiment; and

[0032] Figure 15 is a graph showing the degree of loss of the underlying SOH film for each thickness of the first thin film. DETAILED DESCRIPTION

[0033] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals always refer to like elements. In this regard, these embodiments may have different forms and should not be construed as limited to the description set forth herein. Accordingly, the embodiments are described below only by referring to the drawings to explain aspects of the present specification. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. When an expression such as "at least one" precedes a list of elements, it modifies the entire list of elements and not individual elements in the list.

[0034] Hereinafter, one or more embodiments will be described more fully with reference to the accompanying drawings.

[0035] In this regard, these embodiments may have different forms and should not be construed as limited to the description set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those of ordinary skill in the art.

[0036] The terms used herein are for the purpose of describing particular embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It will also be understood that the terms "comprises" and / or "comprising" specify the presence of the stated features, integers, steps, processes, components, parts and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, processes, components, parts and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] It will be understood that although the terms first, second, etc. may be used herein to describe various components, parts, regions, layers and / or sections, these components, parts, regions, layers and / or sections should not be limited by these terms. These terms do not denote any order, quantity or importance, but are only used to distinguish between individual components, regions, layers and / or sections. Thus, a first component, part, region, layer or section discussed below may be referred to as a second component, part, region, layer or section without departing from the teachings of the embodiments.

[0038] In the present disclosure, "gas" may include evaporated solids and / or liquids, and may include a single gas or a gas mixture. In the present disclosure, the process gas introduced into the reaction chamber through the showerhead may include a precursor gas and an additive gas. The precursor gas and the additive gas may generally be introduced as a mixed gas, or may be introduced separately into the reaction space. The precursor gas may be introduced together with a carrier gas such as an inert gas. The additive gas may include dilution gases such as reaction gases and inert gases. The reaction gas and the dilution gas may be introduced into the reaction space mixedly or separately. The precursor may include two or more precursors, and the reaction gas may include two or more reaction gases. The precursor may be a gas chemisorbed onto the substrate, and generally contains a metalloid or metal element that constitutes the main structure of the matrix of the dielectric film, and the reaction gas for deposition may be a gas that reacts with the precursor chemisorbed onto the substrate when excited to fix an atomic layer or a monolayer onto the substrate. The term "chemisorption" may refer to chemically saturated adsorption. The gas other than the process gas, i.e., the gas not introduced through the showerhead, may be used to seal the reaction space, and it may include a sealing gas such as an inert gas. In some embodiments, the term "film" may refer to a layer that continuously extends in a direction perpendicular to the thickness direction with substantially no pinholes to cover the entire target or related surface, or may refer to a layer that only covers the target or related surface. In some embodiments, the term "layer" may refer to the structure of a film or a synonym thereof or a non-film structure having any thickness formed on the surface. The film or layer may include discrete individual films or layers or multiple films or layers having certain properties, and the boundary between adjacent films or layers may be clear or unclear, and may be set based on physical, chemical, and / or some other properties, the formation process or order of adjacent films or layers, and / or function or purpose.

[0039] In the present disclosure, the expression "including Si-O bonds" may be referred to as being characterized in that one or more Si-O bonds have a main skeleton substantially composed of one or more Si-O bonds and / or have substituents substantially composed of one or more Si-O bonds. The silicon oxide layer may be a dielectric layer including Si-O bonds, and may include a silicon nitride layer (SiN) and a silicon oxynitride layer (SiON).

[0040] In the present disclosure, the expression "same material" should be interpreted to mean that the main constituents (components) are the same. For example, when the first layer and the second layer are both silicon nitride layers and are formed of the same material, the first layer may be selected from the group consisting of Si2N, SiN, Si3N4, and Si2N3, and the second layer may also be selected from the above group, but its specific film quality may be different from that of the first layer.

[0041] In addition, in the present disclosure, the operable range can be determined based on conventional operations. Any two variables can constitute the operable range of the variables, and any indicated range can include or exclude endpoints. Additionally, any indicated value of a variable can refer to an exact value or an approximate value (whether or not they are indicated as "about"), can include equivalents, and can refer to an average value, a median value, a representative value, a majority value, etc.

[0042] In the disclosure where conditions and / or structures are not specified, according to the present disclosure, through conventional experiments, those of ordinary skill in the art can easily provide these conditions and / or structures. In all described embodiments, any component used in the embodiments can be replaced with any of its equivalent components, including those explicitly, necessarily, or essentially described herein, to achieve the intended purpose. In addition, the present disclosure can be similarly applied to devices and methods.

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, due to, for example, manufacturing techniques and / or tolerances, variations from the shown shapes can be expected. Therefore, the embodiments of the present disclosure should not be construed as limited to the specific shapes of the regions shown herein, but may include, for example, shape deviations caused by the manufacturing process.

[0044] Figures 1 to 6 is a cross-sectional view showing a method of manufacturing a semiconductor device according to an embodiment.

[0045] Referring to Figure 1 , the first layer 110 is a film to be etched and is formed on the substrate 100. The film to be etched can be an insulating layer such as a silicon nitride layer or a mask layer for patterning a lower layer, such as an amorphous carbon layer (ACL).

[0046] Thereafter, a second layer is formed on the first layer 110. The second layer can include a polymeric material that can be easily removed as a hard mask through ashing and / or stripping processes. For example, the second layer can include a spin-on hard mask (SOH) film or a carbon spin-on hard mask (C-SOH) film. Then the second layer is patterned to expose at least a portion of the first layer 110. Thus, a substrate 100 including the first layer 110 as the film to be etched and a first patterned structure 120 formed on the first layer 110 can be provided.

[0047] Referring to Figure 2 , a first thin film 130 having a certain thickness is formed on the exposed surfaces of the first layer 110 and the first patterned structure 120 as the second layer. The first thin film 130 can be formed by performing a first cycle that includes supplying a first reactant onto the first patterned structure 120 and purging residues multiple times. As the first cycle is repeated, the thickness of the first thin film 130 can increase.

[0048] In some embodiments, the thickness of the first thin film 130 can be adjusted to achieve a specific purpose. For example, after the first thin film 130 is formed, the first thin film 130 can be changed into a second thin film 135 by reacting with a third reactant (in Figure 3 ). The thickness of the first thin film 130 can be adjusted to prevent damage to the underlying first patterned structure 120, which can occur during the process of changing the first thin film 130 into the second thin film 135 (see Figure 3 ). This will be described in detail with reference to Figure 4 .

[0049] The first reactant for forming the first thin film 130 can include a silicon-containing source gas. In an example, a silicon-containing source gas is supplied onto the first patterned structure 120, whereby a silicon-containing material layer adsorbed (e.g., chemisorbed) on the structure can be formed as the first thin film 130.

[0050] For example, the first reactant can be an amino-silane-based silicon-containing source gas containing an alkyl group such as methyl (-C n H 2n+1 ) or ethyl (-C n H 2n+2 ). That is, the first reactant can include a silicon source containing a carbon element. Therefore, the material layer formed by the first reactant can include silicon and carbon elements.

[0051] In some examples, the first thin film 130 can include a mixture of the elements constituting the first reactant. The first thin film 130 can be formed by adsorbing the mixture onto the first patterned structure 120.

[0052] For example, when the first reactant includes silicon and carbon elements, a first thin film 130 including a mixture of silicon and carbon elements can be formed. The mixture constituting the first thin film 130 can include Si source molecular fragments in which the bonding structure between elements is broken, or can include the individual elements constituting the first reactant (e.g., Si, C, N, or H). In other words, the mixture can be a weak-bond mixture formed by physical bonds weaker than chemical bonds.

[0053] In some embodiments, plasma can be applied during at least a portion of the first cycle to form the first thin film 130. The first reactant is dissociated by the plasma, and the first thin film 130 can be adsorbed onto the first patterned structure 120.

[0054] In some embodiments, to facilitate the dissociation of the first reactant and / or densify the first thin film 130, a second reactant may be supplied during the first cycle. For example, during the application of the above plasma, a second reactant that does not react with the first patterned structure 120 may be supplied. For example, the second reactant may include an inert element such as argon (Ar). By supplying the second reactant, the first thin film 130 can be densified.

[0055] In some embodiments, while the first thin film 130 is being formed, a portion of the first thin film 130 may react with the underlying first patterned structure 120. For example, the first thin film 130 may include chemical bonds formed by one element of the mixture constituting the first thin film 130 that reacts with at least one element of the first patterned structure 120.

[0056] As a more specific example, the first reactant may include a silicon element, so the mixture of the first thin film 130 formed by the first reactant may include a silicon element. At the same time, the first patterned structure 120 under the first thin film 130 may include an oxygen element. In this case, a portion of the thickness of the first thin film 130 may contain Si-O bonds. In particular, Si-O bonds may be formed in the portion of the first thin film 130 adjacent to the first patterned structure 120.

[0057] The Si-O bonds are not formed during the oxidation of the first patterned structure 120, but are formed by the bonding of some oxygen elements (such as some oxygen elements at the O2 termination sites or dangling-bonded oxygen elements) on the top of the first patterned structure 120 to the silicon component on the top of the first thin film 130. Therefore, the first thin film 130 having Si-O bonds can be formed without damaging the first patterned structure 120.

[0058] In addition, the Si-O bonds can be used as a protective film to prevent damage to the first patterned structure 120 during the subsequent process of changing the first thin film 130 to the second thin film 135. In other words, a silicon oxide layer formed in a partial thickness range of the first thin film 130 is formed without damaging the first patterned structure 120, and the silicon oxide layer can protect the first patterned structure 120 during subsequent processing.

[0059] In some embodiments, when the first patterned structure 120 is an SOH structure, a silicon source gas may be supplied on the patterned SOH structure. When a portion of the first thin film 130 is formed due to the supply of the silicon source gas, the residues may be purged. By performing these operations (gas supply and purge) in one cycle and repeating the cycle multiple times, a first thin film 130 with a certain thickness adsorbed on the patterned SOH structure can be formed.

[0060] Refer to Figure 3, after forming the first thin film 130 with a certain thickness, the formation of the second thin film 135 is performed by changing the chemical composition of the first thin film 130. For example, a third reaction material that reacts with the first thin film 130 can be supplied. Due to the supply of the third reactant, the first thin film 130 can be changed into the second thin film 135.

[0061] During the formation of the second thin film 135, the second cycle can be executed multiple times. The second cycle can include supplying the third reactant to the first thin film 130 with a certain thickness and purging the residues. To promote the reaction between the third reaction material and the first thin film 130, plasma can be applied. That is, during the second cycle, the reaction between the first thin film 130 and the third reactant can be caused by applying plasma additionally.

[0062] In the example, the third reactant can include oxygen. In this case, the second thin film 135 can be formed by oxidizing the first thin film 130 during the reaction. For example, when the first patterned structure 120 is an SOH structure and a silicon-containing source gas is supplied to form the first thin film 130, the chemical composition of the first thin film 130 can be changed (e.g., oxidized) by supplying a reaction gas (e.g., oxygen) that reacts with the silicon-containing source gas.

[0063] The third reactant can react with the first patterned structure 120. For example, as described above, the third reaction material can contain oxygen, so when the first patterned structure 120 is an SOH structure, the third reaction material can oxidize the underlying layer of the SOH structure.

[0064] While forming the second thin film 135 by supplying the third reaction material, it is necessary to prevent the oxidation of the SOH structure under the first thin film 130. For this purpose, the first thin film 130 can be formed to have a thickness greater than or equal to a certain thickness. The certain thickness can allow the loss of the underlying first patterned structure 120 that occurs when the third reactant reacts with the first thin film 130 to be less than a certain value. For example, the certain thickness of the first thin film 130 can be at least 15 angstroms (see Figure 15 ).

[0065] On the other hand, the number of repetitions of the second cycle can be adjusted to prevent damage to the first patterned structure 120. For example, in the case of the second cycle, where oxygen is supplied to oxidize the first thin film 130 with a certain thickness and plasma is applied, excessive repetition of the second cycle can cause oxidation of the first patterned structure 120. Therefore, the second cycle can be repeated within the range where oxidation of the first patterned structure 120 does not occur. For example, the second cycle can be repeated 1 to 10 times, and in a specific example, the second cycle can be repeated 1 to 5 times (see Table 1 below).

[0066] Residues purged during a second cycle for forming the second thin film 135 may include constituent elements of the first thin film 130. For example, the first thin film 130 may include Si source molecular fragments (e.g., Si-N-, Si-C-, Si-H-, and Si-C n H 2n+1 ), where the bonding structure between elements is broken or individual elements (e.g., Si, C, N, and H). In such a case, residues including at least one of CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2 may be purged during the second cycle.

[0067] Refer to Figure 4 , and a third thin film 140 is formed on the second thin film 135. To form the third thin film 140, atomic layer deposition (ALD) processing may be used. For example, a third thin film 140 with a desired thickness may be formed by repeatedly performing a third cycle including a source supply operation, a source purge operation, a reactant supply operation, and a reactant purge operation multiple times. In another example, chemical vapor deposition (CVD) processing using a first reactant and a third reactant may be used to form the third thin film 140. Cyclic CVD processing may be used during the CVD processing.

[0068] In some embodiments using ALD processing, the above-mentioned first reactant (e.g., a silicon-containing source gas) may be used as the source, and the third reactant (e.g., a reactive gas that reacts with the source gas such as oxygen) may be used as the reactant. Thus, the third thin film 140 may include the same composition as the second thin film 135.

[0069] For example, the third cycle may include supplying the first reactant on the second thin film 135 and supplying the third reactant in a plasma atmosphere. When using ALD processing to form the third thin film 140, the third cycle may further include purging residues after supplying the first reactant and purging residues after supplying the third reactant.

[0070] Refer to Figure 5 , and a spacer pattern SP for the structure is formed. To this end, at least a part of the second thin film 135 is removed. More specifically, the spacer pattern SP for the first patterned structure 120 is formed by removing at least a part of the second thin film 135 and the third thin film 140. For example, by performing a wet etching process on the second thin film 135 and the third thin film 140, the spacer pattern SP may be formed by etching back the second thin film 135 and the third thin film 140 formed on the first patterned structure 120.

[0071] Refer to Figure 6, Thereafter, the first patterned structure 120 is removed. Thus, the remaining portions of the second thin film 135 and the third thin film 140 (i.e., the spacer pattern SP) can be used as a mask to etch the first layer 110 which is the film to be etched. As described above, according to some embodiments, the spacer pattern SP can be formed by using a thin film with a dual structure (i.e., the second thin film 135 and the third thin film 140), and the patterning of the lower structure can be performed by using the spacer pattern SP as a mask.

[0072] In some other embodiments, the spacer pattern SP' can be formed by using only the second thin film 135 ( Figure 9 ). In this case, at least a part of the second thin film 135 will be removed to form the spacer pattern (see Figure 9 ). In the case of using a thin film with a dual structure to form the spacer pattern SP ( Figure 5 ) and in the case of using only a thin film with a single-layer structure to form the spacer pattern SP' ( Figure 9 ), it should be noted that at least a part of the second thin film 135 is removed to form the spacer pattern.

[0073] The spacer pattern SP formed as described above can include a first protrusion P1, a second protrusion P2, and a third protrusion P3 protruding from the first layer 110 which is the lower structure. In this case, the difference between the first interval d1 between the first protrusion P1 and the second protrusion P2 and the second interval d2 between the second protrusion P2 and the third protrusion P3 can be less than 5 angstroms.

[0074] As described above, since the dual patterning technique (DPT) spacer pattern is formed by changing the first thin film 130 to the second thin film 135 after forming the first thin film 130 with a sufficient thickness to minimize the reaction with the first patterned structure 120, the problem of damage to the hard mask in the DPT process can be prevented. As a result, the mask formed by the residual spacer can have a uniform internal space critical dimension (CD) and external space CD, and the features can be aligned, thereby improving the yield of the final product and achieving good product characteristics.

[0075] Figures 7 to 10 is a diagram showing a substrate processing method according to an embodiment. The substrate processing method according to an embodiment can be a variation of the substrate processing method according to the above-described embodiment. Hereinafter, a repeated description of the embodiment will not be given.

[0076] Figures 1 to 6 shows the process of forming the spacer pattern SP by using a thin film with a dual structure (i.e., the second thin film 135 ( Figure 6 ) and the third thin film 140 ( Figure 6 )), while Figures 7 to 10The embodiment shown in [reference] shows the process of forming the spacer pattern SP' using a thin film with a single-layer structure (i.e., the second thin film 135).

[0077] Referring to Figure 7 , a first thin film 130 with a certain thickness is formed on the exposed surfaces of the first layer 110 and the first patterned structure 120 as the second layer. In this case, the first thin film 130 can be formed to have the thickness required for forming the spacer pattern.

[0078] Referring to Figure 8 , the second thin film 135 is formed by changing the chemical composition of the first thin film 130 with a certain thickness. To this end, a third reactant can be supplied, and as described above, by forming the first thin film 130 with a thickness equal to or greater than a certain value, the reaction between the third reaction material and the underlying first patterned structure 120 can be minimized. In addition, during the formation of the first thin film 130, by forming a layer (such as a silicon oxide layer) with a chemical bond (such as a Si - O bond) between the first thin film 130 and the first patterned structure 120, damage to the underlying first patterned structure 120 due to the supply of the third reactant can be prevented.

[0079] Thereafter, referring to Figure 9 , at least a part of the second thin film 135 is removed to form the spacer pattern SP' for the first patterned structure 120. Moreover, as shown in Figure 10 , the first patterned structure 120 is removed to use the spacer pattern SP' as a mask. This spacer mask with a single-layer structure is different from the spacer mask with a double-layer structure in the above embodiment, but in both cases, it should be noted that commonly, the first thin film 130 is formed of a mixture with weak bonds having a sufficient thickness, and the first thin film 130 is transformed into the second thin film 135 to form at least a part of the spacer mask.

[0080] Figure 11 is a diagram showing damage to the SOH film below the SiO2 film and related problems due to oxygen radicals when depositing the SiO2 film by supplying oxygen radicals on the patterned structure during the patterning process.

[0081] In Figure 11 , on the substrate to be patterned, as a mask film for forming a pattern on a patterned structure such as the SOH film, the SiO2 film is uniformly deposited on the SOH film by the PEALD method. Subsequently, through a selective etching process, the patterned structure is removed and the mask film is retained, and when the etching process continues thereafter, the patterned structure is finally retained on the substrate.

[0082] Ideally, the intervals between the mask films, i.e., the CDs, are the same (A = B = C). However, in reality, as shown in Figure 11As shown, in the initial stage of the deposition of the SiO2 film, the SOH film reacts with oxygen radicals as reaction gases, thus losing its original shape, and the intervals between the mask films, i.e., CDs, are different (A≠B≠C), which can lead to semiconductor device defects.

[0083] Therefore, the present disclosure provides a method capable of minimizing the loss or deformation of the underlying layer when depositing a thin film using active radicals on a patterned structure. Figure 12 Such a substrate processing method is exemplarily shown. Figure 12 The operation can be described as follows.

[0084] Operation 101: Mount a substrate having a patterned structure formed thereon on a reactor. The patterned structure can be a mask film for forming a pattern on the substrate. For example, the material of the mask film can be SOH or a polymeric material for forming the mask film.

[0085] Operation 201: Supply a first reactant and a second reactant onto the patterned structure to form a first film. The second reactant can be a material that does not react with the first reactant and the patterned structure. In one embodiment, the second reactant can be an inert gas activated by high-frequency power applied to the reaction space, such as Ar radicals. The first reactant is a material including the thin film constituent material, and can be a liquid material, and can be supplied to the substrate in a vapor state by a carrier gas. In one embodiment, the first reactant can be a source material containing Si element. The first thin film can be formed while continuously supplying the first reactant and the second reactant, and this process is repeated multiple times. In the second operation, since the second reactant does not chemically react with the first reactant, the first thin film to be deposited can include the first reactant dissociated by the applied high-frequency power, such as the constituent material of the source material, and at the same time, it is densified on the substrate by the second reactant. For example, when the first reaction material is a Si source material containing carbon, nitrogen, and hydrogen components, the first thin film can include Si source molecule fragments in which the bonding structure between the constituent elements is broken, and / or the first reaction material can include individual Si, carbon, nitrogen, hydrogen elements, any mixture of the corresponding elements, or a weak bond mixture having a physical bond weaker than a chemical bond.

[0086] Operation 301: Supply a third reactant onto the first film formed in the second operation (step 2). The third reactant is a material that chemically reacts with the first reactant, and can be, for example, an oxygen-containing active gas.

[0087] Operation 401: The first thin film is converted into a second thin film through a chemical reaction between the first thin film formed on the substrate in the second operation (Step 2) and the third reactant supplied in the third operation (Step 3). In one embodiment, this conversion can be a process of oxidizing the first thin film. For example, when the first thin film is a mixture containing Si element and the third reactant is an oxygen radical, the second thin film can be SiO2. In the fourth operation, by-products generated in the reaction between the first thin film and the third reactant are removed and discharged from the reactor.

[0088] Operation 501: A third thin film is formed on the second thin film. The third thin film can have the same film quality as the second thin film. For example, the third thin film can be a SiO2 thin film. The third thin film can be formed by alternately and continuously supplying the first reactant and the third reactant. In one embodiment, the third thin film can be a SiO2 film formed by the PEALD method.

[0089] Figure 13 FIG. is a diagram showing a substrate processing method according to an embodiment. The substrate processing method according to the embodiment can be a modification of the substrate processing method according to the above embodiment. Hereinafter, a repeated description of the embodiment will not be given.

[0090] Referring to Figure 13 , a substrate is processed using a first reactant, a second reactant, and a third reactant. Hereinafter, the description will be made on the premise that the first reactant contains a Si source material (e.g., a precursor), the second reactant contains Ar, and the third reactant contains oxygen (O2).

[0091] Step 1: Perform a protective layer formation step. In Step 1, while alternately supplying the Si source material and Ar gas, a first thin film is formed on the SOH patterned structure. When Ar gas is supplied, high-frequency power is supplied to the reaction space to dissociate the Si source gas and Ar gas. Since no chemical reaction occurs between the Si source material and Ar plasma, the first thin film includes the Si source material dissociated by the applied high-frequency power. When the Si source material is an aminosilane gas composed of nitrogen and an alkyl group (C n H 2n+1 ) (e.g., diisopropylaminosilane (DIPAS)), the Si source material can be a Si source molecular fragment in which the bonding structure between the constituent elements (individual Si, carbon, nitrogen, and hydrogen elements or a mixture of the corresponding elements) is broken. The Si source material can be a mixture of weak bonds formed by physical bonds weaker than chemical bonds. However, the first layer of the silicon source material adsorbed on the patterned structure can react with the H-terminated sites on the surface of the lower patterned structure to form -Si-O- chemical bonds.

[0092] In Step 1, due to the ion bombardment effect of Ar radicals, the first thin film can be denser on the SOH patterned structure. By activating Ar gas other than oxygen to form the first thin film on the SOH patterned structure, it has the technical effect of preventing deformation of the underlying SOH patterned structure.

[0093] Step 1 is repeated multiple times (m times) to form the first thin film with a certain thickness. The thickness of the first thin film needs to be within the range of the thickness of the second thin film that can be converted into the SiO2 component without deforming the SOH structure when oxygen radicals penetrate into the first thin film, and a detailed description will be provided later.

[0094] Step 2: After Step 1, an oxygen treatment and oxidation step are carried out. In Step 2, while supplying oxygen, the first thin film is converted into the second thin film, i.e., the SiO2 film. When supplying oxygen as the third reactant, high-frequency power is applied to the reaction space to form oxygen radicals, and these oxygen radicals chemically react with the molecular fragments bonded to silicon in the first thin film to form the SiO2 thin film. For example, molecular fragments containing Si elements such as Si-N-, Si-C-, Si-H-, and Si-C n H 2n+1 and oxygen radicals can chemically react with each other to form the SiO2 film. As examples of by-products of the chemical reaction, there may be various combinations of by-products such as CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2, etc., which are purged by the Ar purge gas and removed from the reaction space. Therefore, Step 2 has the technical effect of converting the first thin film into the SiO2 film while minimizing the deformation of the underlying SOH film caused by oxygen radicals due to the certain thickness of the first thin film.

[0095] Step 3: After Step 2, the SiO2 film is formed. In Step 3, a third thin film is chemically deposited on the second thin film. In Step 3, while alternately and continuously supplying the Si source material as the first reactant and oxygen radicals as the third reactant, a third thin film of SiO2 is chemically deposited on the second thin film. Preferably, the second thin film and the third thin film have the same film quality, and problems such as peeling of the second thin film and the third thin film that may occur during subsequent heat treatment can be prevented.

[0096] Table 1 below shows an example of the experimental conditions under which the above-described embodiments Figure 12 are carried out.

[0097]

Table 1

[0098]

[0099]

[0100]

[0101] Figure 14 is a flowchart of a substrate processing method according to an embodiment. The substrate processing method according to the embodiment may be a modification of the substrate processing method according to the above-described embodiment. Hereinafter, a repeated description of the embodiment will not be given.

[0102] Referring to Figure 14 , a SOH patterned structure 1 (14(a)) is prepared, and a Si source material is supplied to the SOH patterned structure 1 to form a first thin film 2 (14(b)) on the patterned structure 1. Thereafter, oxygen radicals are supplied to convert the first thin film 2 into a second thin film 3 (14(c)) having a SiO2 composition. Thereafter, a third thin film 4 (14(d)) having a SiO2 composition is formed on the second thin film 3. Through this process, deformation or loss of the SOH patterned structure 1 caused by oxygen radicals can be minimized.

[0103] Figure 15 shows the degree of loss of the underlying SOH film, which depends on the thickness of the first thin film formed according to the above process. Referring to Figure 15 , it can be seen that when the first thin film is at least , the degree of loss of the SOH film is reduced to or less, which is an allowable range. Therefore, in the formation of the first thin film performed in the above embodiment, it is preferable to repeat the cycle so that the thickness of the first thin film is at least

[0104] In some embodiments, the third thin film may not be formed separately, and the first thin film may be formed thicker and then converted into the second thin film. In this case, by increasing the application time of high-frequency power or increasing the power amount, the second reactive material is sufficiently chemically reacted with the first thin film.

[0105] It should be understood that the embodiments described herein should be considered only in a descriptive sense and not for purposes of limitation. The description of each feature or aspect in each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as defined by the following claims.

Claims

1. A substrate processing method, comprising: forming a first thin film with a certain thickness adsorbed on a patterned spin-on hard mask (SOH) structure by performing a first cycle multiple times, the first cycle including supplying a silicon source gas as a first reactant onto the patterned SOH structure, purging residues, and forming an inert gas plasma by supplying an inert gas as a second reactant such that the constituent materials of the first reactant are adsorbed on the substrate, thereby forming the first thin film, wherein the inert gas does not react with respect to the first reactant to dissociate the silicon source gas; and after forming the first thin film, forming a second thin film by changing the chemical composition of the first thin film by performing a second cycle multiple times, the second cycle including supplying a reaction gas that reacts with the patterned SOH structure and reacts with the silicon source gas, and purging residues.

2. The substrate processing method according to claim 1, wherein, the first thin film is densified by the second reactant.

3. The substrate processing method according to claim 1, wherein, The second cycle further includes: supplying a third reactant onto the first thin film with a certain thickness; applying a plasma to cause a reaction between the first thin film and the third reactant; and purging residues.

4. The substrate processing method according to claim 3, wherein, the third reactant includes oxygen, and the first thin film is oxidized during the reaction.

5. The substrate processing method according to claim 3, wherein, The thickness of the first thin film is greater than or equal to a certain thickness, and the loss of the structure that occurs when the third reactant reacts with the first thin film is less than a certain value.

6. The substrate processing method according to claim 5, wherein, The certain thickness is at least 15 angstroms.

7. The substrate processing method according to claim 1, wherein, The residues purged during the second cycle include at least one of CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2.

8. The substrate processing method according to claim 1, wherein, The first thin film includes a mixture of elements constituting the first reactant, and the first thin film is formed by adsorbing the mixture onto the patterned SOH structure.

9. The substrate processing method according to claim 8, wherein, The first thin film includes chemical bonds formed by reaction of one element in the mixture with at least one element constituting the patterned SOH structure.

10. The substrate processing method according to claim 1, further comprising: removing at least a portion of the second thin film to form a spacer pattern for the structure; removing the patterned SOH structure; and using the spacer pattern as a mask to pattern a lower structure.

11. The substrate processing method according to claim 10, wherein, the spacer pattern includes a first protrusion, a second protrusion, and a third protrusion protruding from the lower structure, and the difference between a first distance between the first protrusion and the second protrusion and a second distance between the second protrusion and the third protrusion is less than 5 angstroms.

12. The substrate processing method according to claim 1 further includes: Forming a third thin film having the same composition as the second thin film on the second thin film.

13. The substrate processing method according to claim 12, further comprising: exposing the structure by performing an etch-back on the second thin film and the third thin film; removing the structure; and using the remaining portions of the second thin film and the third thin film as a mask to pattern a lower structure.

14. The substrate processing method according to claim 12, wherein, During the formation of the third thin film, the third cycle is performed multiple times, wherein the third cycle includes: supplying the first reactant onto the second thin film; purging the residue of the first reactant; supplying a third reactant in a plasma atmosphere; and purging the residue of the third reactant.

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