Substrate processing method

Abstract

A substrate processing method for preventing damage to a lower patterned structure includes: forming a first film having a specific thickness by performing a first cycle multiple times, the first cycle including supplying a first reactant to a structure and purging a residue, and forming a second film by changing a chemical composition of the first film having the specific thickness.

Description

Technical Field

[0001] One or more embodiments relate to a substrate processing method, and more specifically, to a substrate processing method for a structure formed on a patterned substrate. Prior Technology

[0002] When depositing thin films on patterned structures on a substrate using plasma, free radical reactive species can damage the patterned structure. For example, damage to the spin-on hard mask film may occur when the patterned structure (such as a spin-on hard mask (SOH)) includes a polymeric material. More specifically, when an oxygen-deposited thin film is applied to a substrate on which a spin-on hard mask film is formed, oxygen free radical reactive species are generated by plasma application, and the spin-on hard mask film beneath the film reacts with these oxygen free radicals, thereby altering the film quality or causing substantial damage to the spin-on hard mask film. Due to the damage to the underlying patterned structure, the spacing between patterns may become non-constant in subsequent patterning processes. Summary of the Invention

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

[0004] Additional features will be set forth in part in the following description, and in part will be apparent from the description or may be learned by practicing the embodiments set forth in this disclosure.

[0005] According to one or more embodiments, a substrate processing method includes forming a first film having a specific thickness by performing a first cycle a plurality of times, the first cycle including supplying a first reactant on a structure and purging a residue; and forming a second film by changing a chemical composition of the first film having the specific thickness.

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

[0007] According to another example of the substrate processing method, plasma can be applied during at least a portion of the first cycle, and the first reactant can be adsorbed onto the first thin film on this structure by plasma dissociation.

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

[0009] According to another example of the substrate processing method, a second cycle is performed multiple times during the formation of the second thin film, wherein the second cycle may include supplying a third reactant on a first thin film having a specific thickness, inducing a reaction between the first thin film and the third reactant by applying plasma, and purging a residue.

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

[0011] According to another example of the substrate processing method, the third reactant may be reactive with this structure.

[0012] According to another example of the substrate processing method, the first film may have a thickness greater than or equal to a specific thickness, which allows the loss of this structure that occurs while the third reactant reacts with the first film to be less than a specific value.

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

[0014] According to another example of the substrate processing method, the residues purged during the second cycle may 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 constituting the first reactant, and the first thin film can be formed by adsorbing the mixture onto the structure.

[0016] According to another example of the substrate processing method, the first thin film may include a chemical bond formed by the reaction of one element of the mixture with at least one of the elements constituting the structure.

[0017] According to another example of the substrate processing method, the substrate processing method may further include removing at least a portion of the second thin film to form a spacer pattern for the structure, removing the structure, and using the spacer pattern as a mask to pattern the lower structure.

[0018] According to another example of the substrate processing method, the spacer pattern may include 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 may be less than 5 angstroms.

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

[0020] According to another example of the substrate processing method, the substrate processing method may further include exposing the structure by performing etch-back on the second and third films, removing the structure, and using the remaining portions of the second and third films as a mask to pattern the lower structure.

[0021] According to another example of the substrate processing method, a third cycle is performed multiple times during the formation of the third thin film, wherein the third cycle may include supplying a first reactant on the second thin film, purging residues of the first reactant, supplying a third reactant under a plasma atmosphere, and purging residues 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 one example of a substrate processing method, the substrate processing method may further include forming a third thin film on a 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 film with a specific thickness adsorbed on a patterned spin-coated hard mask structure by performing a first cycle multiple times, the first cycle including supplying a silicon-containing source gas and purging a residue on a patterned spin-coated hard mask (SOH) structure; forming a second film by performing a second cycle multiple times to change one of the chemical compositions of the first film, the second cycle including supplying a reaction gas that reacts with the patterned spin-coated hard mask structure and with the silicon-containing source gas and purging a residue; and forming a third film with the same composition as the second film on the second film by performing a third cycle multiple times, the third cycle including supplying a silicon-containing source gas and supplying a reaction gas. Simple Explanation of the Diagram

[0025] The above and other features, characteristics, and advantages of certain embodiments of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein: Figures 1 through 6 are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment; Figures 7 through 10 are views illustrating a substrate processing method according to an embodiment; Figure 11 illustrates the damage to the spin-coated hard mask film caused by oxygen free radicals and related issues during the deposition of SiO2 film by supplying oxygen free radicals on the patterned structure in the patterning process. Figure 12 illustrates a flowchart of a method that minimizes the loss or deformation of the underlying film when depositing thin films using active radicals on patterned structures. Figure 13 illustrates a view of a substrate processing method according to an embodiment; Figure 14 is a flowchart of a substrate processing method according to an embodiment; and Figure 15 is a diagram showing the degree of loss of the spin-coated hard mask film at various thicknesses of the first film. Implementation

[0026] Detailed reference will now be made to embodiments, examples of which are illustrated in the accompanying drawings, wherein similar reference numerals throughout refer to similar elements. In this respect, embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, the following description of embodiments is solely by way of reference to the accompanying drawings to explain the nature of this specification. As used herein, the term "and / or" includes any and all combinations of one or more of the associated list items. When a statement such as "at least one of" precedes a list of elements, it modifies the entire list of elements rather than individual elements of the list.

[0027] In the following description, one or more embodiments will be described more fully with reference to the accompanying drawings.

[0028] In this regard, the embodiments may take different forms and should not be construed as being limited to the description set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0029] The terminology used herein is for the purpose of describing specific embodiments and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular forms "a" and "the" as used herein are intended to include the plural forms as well. It will be further understood that the terms "includes" and / or "comprises" as used herein indicate the presence of groups of the stated features, integers, steps, processes, components, and / or such features, integers, steps, processes, components, and / or such features, integers, steps, processes, components, and / or such features, integers, and / or such features, but do not preclude the presence or addition of one or more other groups of features, integers, steps, processes, components, and / or such features. As used herein, the term "and / or" includes any and all combinations of one or more of the associated list items.

[0030] It will be understood that while 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 indicate any order, number, or importance, but are used only to distinguish one component, region, layer, and / or section from another. Therefore, without departing from the teachings of the embodiments, the first component, part, region, layer, or section discussed below may be referred to as the second component, part, region, layer, or section.

[0031] In this disclosure, "gas" may include evaporated solids and / or liquids, and may include a single gas or a mixture of gases. In this disclosure, the process gas introduced into the reaction chamber via a spray head may include precursor gases and additive gases. Precursor gases and additive gases may generally be introduced as a mixed gas or may be introduced separately into the reaction space. Precursor gases may be introduced together with a carrier gas (such as an inert gas). Additive gases may include diluent gases (such as reactant gases and inert gases). Reactant gases and diluent gases may be introduced into the reaction space mixed or separately. Precursors may include two or more precursors, and reactant gases may include two or more reactant gases. Precursors may be gases chemically adsorbed onto the substrate and generally contain metalloid or metallic elements that constitute the main structure of the dielectric film matrix, while the reactant gas used for deposition may be a gas that reacts with the precursor chemically adsorbed onto the substrate when excited to fix an atomic layer or monolayer onto the substrate. The term "chemisorption" may refer to chemically saturated adsorption. A gas distinct from the process gas (i.e., a gas introduced without passing through the spray nozzle) may be used to seal the reaction space, and this may include a sealing gas (such as an inert gas). In some embodiments, the term "film" may refer to a layer that is substantially free of pinholes and extends continuously in a direction perpendicular to the thickness direction, covering the entire target or related surface, or may refer to a layer that simply covers the target or related surface. In some embodiments, the term "layer" may refer to a structure of any thickness formed on a surface, or a synonym for a membrane or non-membrane structure. A membrane or layer may include a discrete single membrane or layer or multiple membranes or layers having certain properties, and the boundaries between adjacent membranes or layers may be clear or unclear, and may be defined based on the physical, chemical, and / or other properties, formation process or sequence, and / or function or purpose of adjacent membranes or layers.

[0032] In this disclosure, the phrase "containing a Si-O bond" can be described as characterized by one or more Si-O bonds, having a skeleton substantially composed of one or more Si-O bonds, and / or having substituents substantially composed of one or more Si-O bonds. The silicon nitride layer can be a dielectric layer containing Si-O bonds, and may include silicon oxide (SiN) and silicon oxynitride (SiON) layers.

[0033] In this disclosure, the expression “same material” shall be interpreted to mean that the principal component(s) are identical. For example, when both the first and second layers are silicon nitride layers and formed from the same material, the first layer may be selected from the group consisting of Si2 N, SiN, Si3 N4, and Si2 N3, and the second layer may also be selected from the above group, but the specific membrane quality of this second layer can be different from that of the first layer.

[0034] Furthermore, in this disclosure, according to the actionable range can be judged on the basis of general work, any two variables may constitute the operable range of the variable, and any indicated range may include or exclude endpoints. Furthermore, the numerical value of any indicator variable may refer to an exact value or an approximate value and may include equivalent values ​​(whether or not such values ​​are indicated by "about") and may refer to the mean, intermediate, representative, multiple values, or similar.

[0035] Where conditions and / or structures are not specifically specified in this disclosure, those with usual knowledge in the technical field to which they belong may readily provide them by virtue of customary experiments in view of this disclosure. In all of the embodiments described, any component used in one embodiment may be replaced by any equivalent component thereof, including those described herein expressly, necessaryly, or substantially for the intended use, and in addition, the disclosure may be similarly applied to devices and methods.

[0036] Embodiments of this disclosure will be described with reference to the accompanying schematics in the following. In the schema, variations of the plotted shapes may be expected due to, for example, manufacturing techniques and / or tolerances. Accordingly, the embodiments of the disclosure should not be interpreted as being limited to the specific regional shapes as plotted herein, but may include, for example, shape deviations resulting from the manufacturing process.

[0037] 1 to 6 illustrate a cross-sectional view of a method of fabricating a semiconductor device according to an embodiment.

[0038] Referring to FIG. The film to be etched may be an insulating layer (such as a silicon nitride layer) or a masking layer (such as an amorphous carbon layer (ACL)) for patterning the lower layer.

[0039] Subsequently, a second layer is formed on the first layer 110. The second layer may include a polymeric material serving as a hard mask, which can be easily removed by ashing and / or stripping processes. For example, the second layer may include a spin-on-hardmask (SOH) film or a carbon spin-on-hardmask (C-SOH) film. Next, the second layer is patterned to expose at least a portion of the first layer 110. Thus, a substrate 100 may be provided, including the first layer 110 as the film to be etched and a first patterned structure 120 formed on the first layer 110.

[0040] Referring to Figure 2, a first thin film 130 of a specific thickness is formed on the exposed surface of the first layer 110 and on the first patterned structure 120, which serves as the second layer. The first thin film 130 can be formed by performing a first cycle multiple times, the first cycle including supplying a first reactant to the first patterned structure 120 and purging residues. The thickness of the first thin film 130 can increase with repetition of the first cycle.

[0041] In some embodiments, the thickness of the first film 130 can be adjusted to achieve a specific purpose. For example, after the first film 130 is formed, it can be transformed into a second film 135 (Figure 3) by reacting with a third reactant. The thickness of the first film 130 can be adjusted to prevent damage to the underlying first patterned structure 120, which can occur during the process of transforming the first film 130 into the second film 135 (refer to Figure 3). This will be described in detail with reference to Figure 4.

[0042] The first reactant used to form the first thin film 130 may include a silicon-containing source gas. In one example, a silicon-containing source gas system is supplied to a first patterned structure 120 such that a layer of silicon-containing material adsorbed (e.g., chemisorbed) on the structure can be formed as the first thin film 130.

[0043] For example, the first reactant can be an aminosilyl-containing silicon source gas containing an alkyl group (such as methyl (-CnH2n+1) or ethyl (-CnH2n+2)). That is, the first reactant can include a silicon source containing carbon. Therefore, the material layer formed from the first reactant can include both silicon and carbon elements.

[0044] In some instances, the first thin film 130 may comprise a mixture of elements constituting the first reactant. The first thin film 130 may be formed by adsorbing the mixture onto the first patterned structure 120.

[0045] For example, when the first reactant includes silicon and carbon, a first thin film 130 comprising a mixture of silicon and carbon can be formed. The mixture comprising the first thin film 130 may include inter-elemental bonding structures in which Si source molecular fragments are disrupted, or may include individual elements constituting the first reactant (e.g., Si, C, N, or H). In other words, the mixture may be a mixture of weak bonds composed of physical bonds weaker than chemical bonds.

[0046] In some embodiments, plasma may be applied during at least a portion of the first cycle to form a first thin film 130. The first reactants are dissociated by plasma, and the first thin film 130 may be adsorbed onto the first patterned structure 120.

[0047] In some embodiments, a second reactant may be supplied during the first cycle to facilitate the dissociation of the first reactant and / or densify the first film 130. For example, during the application of the plasma described above, 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 film 130 can be densified.

[0048] In some embodiments, while forming the first thin film 130, 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, which react with at least one of the elements constituting the first patterned structure 120.

[0049] As a more specific example, the first reactant may include silicon, and therefore the mixture of the first thin film 130 formed from the first reactant may include silicon. Meanwhile, the first patterned structure 120 beneath the first thin film 130 may include oxygen. In this case, a portion of the thickness of the first thin film 130 may contain Si-O bonds. Specifically, Si-O bonds may be formed in a portion of the first thin film 130 adjacent to the first patterned structure 120.

[0050] The Si-O bonds are not formed during the oxidation process of the first patterned structure 120, but are formed by bonding some oxygen elements (e.g., oxygen elements at O2-terminated sites or dangling bonded oxygen elements) to the top of the first patterned structure 120, wherein the silicon component is located at the top of the first thin film 130. Therefore, the first thin film 130 with Si-O bonds can be formed without damaging the first patterned structure 120.

[0051] Furthermore, the Si-O bonds can act as a protective film to prevent the first patterned structure 120 from being damaged in subsequent processes that transform the first thin film 130 into the second thin film 135. In other words, the silicon oxide layer formed in a portion of the thickness 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 processes.

[0052] In some embodiments, when the first patterned structure 120 is a spin-coated hard mask structure, a silicon-containing source gas can be supplied onto the patterned spin-coated hard mask structure. When a portion of the first thin film 130 is formed due to the supply of the silicon-containing source gas, residues can be purged. By performing these operations (gas supply and purging) as a cycle, and performing this cycle multiple times, a first thin film 130 of a specific thickness can be formed adsorbed onto the patterned spin-coated hard mask structure.

[0053] Referring to Figure 3, after forming a first thin film 130 with a specific thickness, the formation of a second thin film 135 is performed by changing the chemical composition of the first thin film 130. For example, a third reactive material that reacts with the first thin film 130 can be supplied. The first thin film 130 can be transformed into the second thin film 135 by supplying the third reactant.

[0054] During the formation of the second film 135, a second cycle may be performed multiple times. The second cycle may include supplying a third reactant to the first film 130 having a specific thickness and purging residues. To promote the reaction between the third reactant and the first film 130, plasma may be applied. That is, during the second cycle, an additional reaction may be performed by applying plasma to induce a reaction between the first film 130 and the third reactant.

[0055] In one instance, the third reactant may include oxygen. In this case, the second film 135 may be formed by oxidizing the first film 130 during the induced reaction. For example, when the first patterned structure 120 is a spin-coated hard mask structure and a silicon-containing source gas is supplied to form the first film 130, the chemical composition of the first film 130 may be altered (e.g., oxidized) by supplying a reactive gas (e.g., oxygen gas) that reacts with the silicon-containing source gas.

[0056] The third reactant may be reactive with the first patterned structure 120. For example, as described above, the third reactant may include oxygen, and thus, when the first patterned structure 120 is a spin-coated hard mask structure, the third reactant may oxidize the lower layer of the spin-coated hard mask structure.

[0057] When forming the second thin film 135 by supplying the third reactive material, it is necessary to prevent oxidation of the spin-coated hard mask structure beneath 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 specific thickness. This specific thickness allows the loss of the underlying first patterned structure 120 that occurs simultaneously with the reaction of the third reactant with the first thin film 130 to be less than a specific value. For example, the specific thickness of the first thin film 130 can be at least 15 angstroms (see Figure 15).

[0058] 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 a second cycle in which oxygen is supplied to oxidize the first film 130 of a specific thickness and plasma is supplied, excessive repetition of the second cycle can lead to oxidation of the first patterned structure 120. Therefore, the second cycle can be repeated within a range that does not cause oxidation of the first patterned structure 120. For example, the second cycle can be repeated 1 to 10 times, and in a particular instance, the second cycle can be repeated 1 to 5 times (see Table 1 below).

[0059] Residues purged during the second cycle to form the second thin film 135 may include the constituent elements of the first thin film 130. For example, the first thin film 130 may include fragments of Si source molecules (e.g., Si-N-, Si-C-, Si-H-, and Si-CnH2n+1) where the inter-elemental bonding structure is disrupted, or individual elements (e.g., Si, C, N, and H). In this case, residues including at least one of CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2 may be purged during the second cycle.

[0060] Referring to Figure 4, a third thin film 140 is formed on the second thin film 135. To form the third thin film 140, an atomic layer deposition (ALD) process can be used. For example, a third thin film 140 of desired thickness can be formed by repeating a third cycle multiple times, this third cycle including a source supply operation, a source purging operation, a reactant supply operation, and a reactant purging operation. In another example, a chemical vapor deposition (CVD) process using a first reactant and a third reactant can be used to form the third thin film 140. A cyclic chemical vapor deposition process can be used during the chemical vapor deposition process.

[0061] In some embodiments using atomic layer deposition (ALD) processes, the first reactant (e.g., a silicon-containing source gas) can be used as a source, and the third reactant (e.g., a reactive gas (such as oxygen) that reacts with the source gas) can be used as a reactant. Therefore, the third film 140 may include the same composition as the second film 135.

[0062] For example, the third cycle may include supplying the first reactant on the second film 135 and supplying the third reactant under plasma atmosphere. When an atomic layer deposition process is used to form the third film 140, the third cycle may further include purging residues after supplying the first reactant and purging residues after supplying the third reactant.

[0063] Referring to Figure 5, a spacer pattern SP for the structure is formed. For this purpose, at least a portion of the second film 135 may be removed. More specifically, the spacer pattern SP for the first patterned structure 120 is formed by removing at least a portion of the second film 135 and the third film 140. For example, the spacer pattern SP can be formed by etching back the second film 135 and the third film 140 formed on the first patterned structure 120 through a wet etching process performed on the second film 135 and the third film 140.

[0064] Referring to Figure 6, the first patterned structure 120 is then removed. Therefore, the first layer 110 of the film to be etched can be etched using the remaining portions of the second film 135 and the third film 140 (i.e., the spacer pattern SP) as a mask. As described above, according to some embodiments, the patterning of the lower structure can be performed by forming the spacer pattern SP using a film with a dual structure (i.e., the second film 135 and the third film 140) and by using the spacer pattern SP as a mask.

[0065] In some other embodiments, the spacer pattern SP' (Figure 9) may be formed using only the second film 135. In this case, at least a portion of the second film 135 is removed to form the spacer pattern (see Figure 9). In both cases where a film with a double structure is used to form the spacer pattern SP (Figure 5) and where a film with a single layer structure is used to form the spacer pattern SP' (Figure 9), it should be noted that at least a portion of the second film 135 is removed to form the spacer pattern.

[0066] The spacer pattern SP formed as described above may include a first protrusion P1, a second protrusion P2, and a third protrusion P3 protruding from the first layer 110 as a lower structure. In this case, the difference between the first distance d1 between the first protrusion P1 and the second protrusion P2 and the second distance d2 between the second protrusion P2 and the third protrusion P3 may be less than 5 angstroms.

[0067] As described above, since the double patterning technology (DPT) spacer pattern is formed by changing the first film 130 into a second film 135 after forming a first film 130 with a thickness sufficient to minimize the reactivity with the first patterned structure 120, it is possible to prevent the problem of hard mask damage in the double patterning technology process. As a result, the mask formed by the residual spacers can have uniform internal critical dimension (CD) and external critical dimension, and the features can be aligned to improve the yield of the finished product and achieve good product characteristics.

[0068] Figures 7 through 10 are views illustrating a substrate processing method according to an embodiment. The substrate processing method according to the embodiment may be a variation of the substrate processing method according to the above embodiments. In the following text, the embodiments will not be described again.

[0069] Figures 1 to 6 illustrate the process of forming spacer pattern SP using a film with a dual structure (i.e., a second film 135 (Figure 6) and a third film 140 (Figure 6)), while the embodiments shown in Figures 7 to 10 illustrate the process of forming spacer pattern SP' using a film with a single-layer structure (i.e., a second film 135).

[0070] Referring to Figure 7, a first thin film 130 of a specific thickness is formed on the exposed surface of the first layer 110 and on the first patterned structure 120, which serves as the second layer. In this case, the first thin film 130 can be formed to have the thickness required to form the spacer pattern.

[0071] Referring to Figure 8, a second thin film 135 is formed by changing the chemical composition of a first thin film 130 having a specific thickness. For this purpose, a third reactant can be supplied, and as described above, by forming a first thin film 130 with a thickness equal to or greater than a specific value, the reaction between the third reactant and the underlying first patterned structure 120 can be minimized. Furthermore, during the process of forming the first thin film 130, by forming a layer (e.g., a silicon oxide layer) with chemical bonds (e.g., Si-O bonds) 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.

[0072] Subsequently, as shown in Figure 9, at least a portion of the second film 135 is removed to form a spacer pattern SP' for the first patterned structure 120. Similarly, as shown in Figure 10, the first patterned structure 120 is removed to use the spacer pattern SP' as a mask. This single-layer spacer mask differs from the double-layer spacer mask of the above embodiments, but in both cases, it should be noted that the first film 130 is formed from a mixture of weak bonds with sufficient thickness, and the first film 130 is transformed into the second film 135 to form at least a portion of the spacer mask.

[0073] Figure 11 illustrates a view showing how the spin-coated hard mask film beneath the SiO2 film is damaged due to oxygen free radicals and related issues when depositing a SiO2 film by supplying oxygen free radicals on the patterned structure during the patterning process.

[0074] In Figure 11, on the substrate where a pattern is to be formed, a SiO2 film is uniformly deposited on the spin-coated hard mask film as a mask film for patterning on a patterned structure (such as a spin-coated hard mask film). Subsequently, the patterned structure is removed by a selective etching process, leaving the mask film, and the patterned structure is ultimately attached to the substrate as the etching process continues thereafter.

[0075] Ideally, the spacing (i.e., the critical dimension) between the masking films is the same (A=B=C). However, in reality, as shown in Figure 11, spin-coated hard masking films react with oxygen free radicals (which are reactive gases) in the initial stage of SiO2 film deposition, thereby losing their original shape, and the spacing (i.e., the critical dimension) between the masking films is different (A#B#C), which leads to defects in semiconductor devices.

[0076] Therefore, this disclosure provides a method for minimizing the loss or deformation of the underlying layer when using active radical deposition of thin films on patterned structures. Figure 12 illustratively shows this substrate processing method. The operation of Figure 12 can be described as follows.

[0077] Operation 101: Mount a substrate on which a patterned structure is formed on it onto the reactor. The patterned structure may be a mask film used to form a pattern on the substrate. For example, the material of the mask film may be a spin-coated rigid mask or a polymeric material used to form the mask film.

[0078] Operation 201: A first reactant and a second reactant are supplied onto a patterned structure to form a first film. The second reactant may be a material that does not react with the first reactant and the patterned structure. In one embodiment, the second reactant may be an inert gas (e.g., Ar radicals) activated by high-frequency power applied to the reaction space. The first reactant is a material comprising the thin film components and may be a liquid material, supplied to the substrate in a vapor state via a carrier gas. In one embodiment, the first reactant may be a source material containing Si. The first thin film can be formed simultaneously with the continuous supply of the first and second reactants, and this process is repeated several times. In the second operation, since the second reactant is not chemically reactive with the first reactant, the first thin film to be deposited may include the first reactant (such as the component material of the source material) dissociated by the application of high-frequency power, and simultaneously densified on the substrate by the second reactant. For example, when the first reactant is a Si source material containing carbon, nitrogen, and hydrogen, the first film may include a bonding structure between the constituent elements that disrupts the Si source molecular fragments, and / or the first reactant may include individual Si, carbon, nitrogen, and hydrogen elements, random mixtures of corresponding elements, or mixtures of weak bonds with physical bonds weaker than chemical bonds.

[0079] Operation 301: A third reactant is supplied onto the first thin film formed in the second operation (step 2). The third reactant is a material that is chemically reactive with the first reactant and may be, for example, an oxygen-containing activating gas.

[0080] 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, the conversion may be a process of oxidizing the first thin film. For example, when the first thin film is a mixture containing Si and the third reactant is an oxygen free radical, the second thin film may be SiO2. In the fourth operation, the byproducts generated in the reaction between the first thin film and the third reactant are removed and discharged from the reactor.

[0081] Operation 501: Forming a third thin film on the second thin film. The third thin film may have the same film quality as the second thin film, and for example, the third thin film may be a SiO2 thin film. The third thin film may be formed by alternately and sequentially supplying the first reactant and the third reactant. In one embodiment, the third thin film may be a SiO2 film formed by a plasma-enhanced atomic layer deposition method.

[0082] Figure 13 is a view illustrating a substrate processing method according to an embodiment. The substrate processing method according to the embodiment may be a variation of the substrate processing method according to the above embodiment. In the following text, the embodiments will not be described again.

[0083] Referring to Figure 13, the substrate is treated using a first reactant, a second reactant, and a third reactant. In the following description, the first reactant will contain a Si source material (e.g., a precursor), the second reactant will contain Ar, and the third reactant will contain oxygen (O2).

[0084] Step 1: Perform the protective layer formation step. In Step 1, a first thin film is formed on a spin-coated hard mask patterned structure while Si source material and Ar gas are alternately supplied. When Ar gas is supplied, high-frequency power is supplied to the reaction space to dissociate the Si source gas and Ar gas. Since the Si source material and Ar plasma do not chemically react, the first thin film includes Si source material dissociated by applying high-frequency power. When the Si source material is an aminosilane gas composed of nitrogen and alkyl (CnH2n+1) (e.g., diisopropylaminosilane, DIPAS), the Si source material can be a fragment of Si source molecules in which the bonding structure between the constituent elements is broken, individual Si, carbon, nitrogen, and hydrogen elements, or mixtures of corresponding elements. The Si source material can be a mixture of weak bonds composed of physical bonds weaker than chemical bonds. However, the outermost layer of the Si source material adsorbed on the patterned structure can react with the H-terminal sites on the surface of the lower patterned structure to form -Si-O- chemical bonds.

[0085] In step 1, due to the ion bombardment effect of Ar radicals, the first film can be made more dense on the spin-coated hard mask patterned structure. By activating Ar gas, which is different from oxygen, the first film is formed on the spin-coated hard mask patterned structure, which has the technical effect of preventing deformation of the underlying spin-coated hard mask patterned structure.

[0086] Repeat step 1 several times (m times) to form a first film with a specific thickness. The thickness of the first film must be within a range that allows it to be transformed into a second film with SiO2 composition without deforming the spin-coated hard mask structure when oxygen free radicals penetrate the first film, and its detailed description will be described later below.

[0087] Step 2: Following Step 1, oxygen treatment and oxidation are performed. In Step 2, while oxygen is supplied, the first film is transformed into a second film (i.e., a SiO2 film). When oxygen, as a third reactant, is supplied, high-frequency power is applied to the reaction space to form oxygen free radicals, which then chemically react with Si-bonded molecular fragments in the first film to form a SiO2 film. For example, Si-containing molecular fragments (such as Si-N-, Si-C-, Si-H-, and Si-CnH2n+1) and oxygen free radicals can chemically react with each other to form a SiO2 film. As examples of byproducts of the chemical reaction, various combinations of byproducts (such as CH4, C2H5, N(C2H5)2, CO2, NO, H2O, H2, etc.) can be removed from the reaction space by purging with Ar purging gas. Therefore, step 2 has the technical effect of converting the first film into a SiO2 film while minimizing the deformation of the lower film of the spin-coated hard mask due to the specific thickness of the first film caused by oxygen free radicals.

[0088] Step 3: Formation of the SiO2 film following Step 2. In Step 3, the third film is chemically deposited on the second film. In Step 3, while the Si source material as the first reactant and the oxygen free radicals as the third reactant are alternately and continuously supplied, the third SiO2 film is chemically deposited on the second film. Preferably, the second and third films have the same film quality, and problems such as peeling of the second and third films that may occur during subsequent heat treatment processes can be prevented.

[0089] Table 1 below shows an example of experimental conditions under which the embodiment of Figure 12 above was performed.

[0090] Table 1 project condition Process temperature (°C) Room temperature to 550 °C (ideally 50 °C to 300 °C) Process pressure (Torr) 1.0 Torr to 5.0 Torr (ideally 2.0 Torr to 3.0 Torr) Si precursor DIPAS (Diisopropylaminosilane) reactants O2 purge gas Ar Step 1 (Protective Film Formation) Process time (seconds) Source supply (S1) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Source purging (S2) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Plasma application (S3) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Purge (S4) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Repeat loop S1 through S4 50 to 200 times (ideally 100 to 150 times) Gas flow rate (sccm) Source vector (Ar) 100 sccm to 10,000 sccm (preferably 600 sccm to 1,200 sccm) Purging gas (Ar) 1,000 sccm to 10,000 sccm (preferably 3,000 sccm to 6,000 sccm) Plasma conditions RF power (W) 100 W to 1,000 W (ideally 200 W to 400 W) RF frequency 13 MHz to 100 MHz (ideally 27 MHz to 60 MHz) The second step (oxygen treatment and oxidation process) Process time (seconds) Pre-purge (S5) 0.05 seconds to 5.0 seconds (preferably 0.5 seconds to 5.0 seconds) Plasma application (S6) 0.05 seconds to 3.0 seconds (preferably 0.1 seconds to 2.0 seconds) Purge (S7) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Repeat S5 and S6 loops 1 to 10 times (ideally 1 to 5 times) Gas flow rate (sccm) Reaction gas (O2) 50 sccm to 1000 sccm (preferably 200 sccm to 500 sccm) Purging gas (Ar) 1,000 sccm to 10,000 sccm (preferably 3,000 sccm to 6,000 sccm) Plasma conditions RF power (W) 100 W to 1,000 W (ideally 200 W to 400 W) RF frequency 13 MHz to 100 MHz (ideally 27 MHz to 60 MHz) Third step (SO film formation step) Process time (seconds) Source supply (S8) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Source purging (S9) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Plasma application (S10) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 2.0 seconds) Purge (S11) 0.05 seconds to 2.0 seconds (preferably 0.1 seconds to 1.0 seconds) Repeat loop S8 through loop S11 1 to 10 times (ideally 1 to 5 times) Gas flow rate (sccm) Source vector (Ar) 100 sccm to 10,000 sccm (preferably 600 sccm to 1,200 sccm) Reaction gas (O2) 50 sccm to 1000 sccm (preferably 200 sccm to 500 sccm) Purging gas (Ar) 1,000 sccm to 10,000 sccm (preferably 3,000 sccm to 6,000 sccm) Plasma conditions RF power (W) 100 W to 1,000 W (ideally 200 W to 400 W) RF frequency 13 MHz to 100 MHz (ideally 27 MHz to 60 MHz)

[0091] 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 variation of the substrate processing method according to the above embodiment. In the following text, the embodiments will not be described again.

[0092] Referring to Figure 14, a spin-coated hard mask patterned structure 1 is prepared (14(a)), and Si source material is supplied to the spin-coated hard mask patterned structure 1 to form a first thin film 2 on the patterned structure 1 (14(b)). Subsequently, oxygen free radicals are supplied to convert the first thin film 2 into a second thin film 3 with SiO2 composition (14(c)). Subsequently, a third thin film 4 with SiO2 composition is formed on the second thin film 3 (14(d)). Through this process, the deformation or loss of the spin-coated hard mask patterned structure 1 caused by oxygen free radicals can be minimized.

[0093] Figure 15 illustrates the wear level of the spin-coated hard mask film, which depends on the thickness of the first film formed according to the above process. Referring to Figure 15, it can be seen that when the first film is at least 15 angstroms thick, the wear level of the spin-coated hard mask film is reduced to 5 angstroms or less, which is within the acceptable range. Therefore, in the formation of the first film performed in the above embodiments, it is preferable to repeat the cycle so that the first film has a thickness of at least 15 angstroms.

[0094] In some embodiments, a third film may not be formed additionally, and the first film may be formed to be thicker and then transformed into a second film. In this case, the second reactive material reacts sufficiently with the first film by increasing the time for applying high-frequency power or by increasing the amount of power.

[0095] It should be understood that the embodiments described herein are for descriptive purposes only and not for limiting purposes. The descriptions of features or mannerisms within each embodiment should generally be considered as applicable to other similar features or mannerisms in other embodiments. Although one or more embodiments have been described with reference to drawings, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the following claims.

[0096] 1: Patterned structure 2: First Thin Film 3: Second thin film 4: Third Thin Film 100:Substrate 101: Operation 110: First floor 120: First patterned structure 130: First Thin Film 135: Second thin film 140: Third Thin Film 201: Operation 301: Operation 401: Operation 501: Operation A: Spacing B: Spacing C: Spacing d1: Distance d2: Distance P1: First protrusion P2: Second protrusion P3: Third protrusion SP: Spacer pattern SP': Spacer pattern

Claims

1. A substrate processing method, comprising: A first thin film of a specific thickness is formed by performing a first cycle multiple times, adsorbed on a patterned spin-coating hard mask structure. The first cycle includes supplying a silicon-containing source gas as a first reactant to the patterned spin-coating hard mask structure and purging a residue; and forming an inert gas plasma by providing an inert gas as a second reactant to dissociate the silicon-containing source gas, so that a derivative of the first reactant is adsorbed on the substrate, thereby forming the first thin film. After the step of forming the first thin film, a second thin film is formed by performing a second cycle multiple times to transform the chemical composition of the first thin film. The second cycle includes supplying a reactive gas that reacts with the patterned spin-coating hard mask structure and reacts with the silicon-containing source gas, and purging the residue.

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

3. The substrate processing method of claim 1, wherein the first film comprises a mixture of elements constituting the first reactant, and the first film is formed by adsorbing the mixture onto the patterned spin-coating hard mask structure.

4. The substrate processing method of claim 3, wherein the first thin film includes a chemical bond formed by reacting one element of the mixture with at least one of the elements constituting the patterned spin-coated hard mask structure.

5. The substrate processing method as described in claim 1 further includes: At least a portion of the second film is removed to form a spacer pattern for the patterned spin-coated hard mask structure; Remove the patterned spin-coated hard mask structure; and use the spacer pattern as a mask to pattern the lower structure.

6. The substrate processing method of claim 5, 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.

7. The substrate processing method of claim 1 further includes forming a third film having the same composition as the second film on the second film.

8. The substrate processing method as described in claim 7 further includes: The patterned spin-coated hard mask structure is exposed by performing back etching on the second and third films; Remove the patterned spin-coated hard mask structure; and use the remaining portion of the second and third films as a mask to pattern the lower structure.

9. The substrate processing method of claim 7, wherein a third cycle is performed multiple times during the formation of the third thin film, wherein the third cycle includes: The first reactant is supplied on the second film; Purge the residue of one of the first reactants; The third reactant is supplied under a plasma atmosphere; and one of the residues of the third reactant is purged.

10. The substrate processing method of claim 1 further includes forming a third film having the same composition as the second film on the second film by performing a third cycle a plurality of times, the third cycle including supplying the silicon-containing source gas.

11. The substrate processing method of claim 10, wherein forming the third thin film includes applying an oxygen plasma to induce a reaction between the first thin film and the reactive gas.

12. The substrate processing method of claim 10, wherein the residues purged during the second cycle include at least one of CH4, C2H5, N(C2H5)2, CO2, NO, H2O, and H2.

13. The substrate processing method of claim 10, wherein the reaction gas includes oxygen.

14. The substrate processing method of claim 13, wherein the first thin film has a thickness greater than or equal to a specific thickness, the thickness allowing the loss of one of the patterned spin-coated hard mask structures occurring simultaneously with the reaction of the third reactant with the first thin film to be less than a specific value.

15. The substrate processing method of claim 13, wherein the specific thickness is at least 15 angstroms.

16. A substrate processing method, comprising: A first thin film of a specific thickness is formed by performing a first cycle multiple times, adsorbed on a patterned spin-coating hard mask structure. The first cycle includes supplying a silicon-containing source gas to the patterned spin-coating hard mask structure, purging residues, and forming an inert gas plasma to dissociate the silicon-containing source gas, causing a derivative of a first reactant to adsorb onto the substrate, thereby forming the first thin film. After forming the first thin film, a second thin film is formed by performing a second cycle multiple times, transforming one of the chemical compositions of the first thin film. The second cycle includes supplying a reaction gas that reacts with the patterned spin-coating hard mask structure and the silicon-containing source gas, and purging residues. A third thin film with the same composition as the second thin film is formed on the second thin film by performing a third cycle multiple times. The third cycle includes supplying the silicon-containing source gas and the reaction gas.

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