Substrate processing method

Abstract

A substrate processing method capable of improving etch selectivity without increasing power includes: structurally forming a first thin film; forming a material layer on the first thin film with a wet etch resistance greater than that of the first thin film; removing a portion of the material layer using wet etching to expose a portion of the first thin film; and removing the exposed portion of the first thin film.

Description

Technical Field

[0001] One or more embodiments relate to substrate processing methods, and more specifically, to substrate processing methods capable of improving etch selectivity without increasing power. Background Technology

[0002] Recently, the need to perform selective deposition processes on patterned three-dimensional (3D) structures has increased. For example, in the fabrication of 3D NAND flash memory devices, processes have been used to selectively deposit only the upper part of a stepped structure. To achieve this selective deposition, it is necessary to increase the etch selectivity of the thin films deposited on the top and sides of the patterned structure.

[0003] For example, plasma can be applied to increase the etch selectivity of the films deposited on the top and sides of a patterned structure. Due to the linearity of the free radicals generated by plasma application and the ion bombardment effect, the films on the top and bottom of the patterned structure can be densified in the direction perpendicular to the free radical propagation direction. On the other hand, the films on the sides of the patterned structure may be less dense than those on the top and bottom of the patterned structure in the direction parallel to the free radical propagation direction. Therefore, the films on the sides of the patterned structure can be removed by wet etching, while the films on the top and bottom of the patterned structure can be retained.

[0004] The effect of free radicals on the densification and etch selectivity of thin films is limited. For example, even when a certain RF power is applied, the desired etch selectivity of films deposited on the top and sides of a patterned structure may not be achieved. Therefore, higher RF power can be applied to overcome this, in which case damage may occur inside the reactor. Components inside the reactor, such as spray heads, may be damaged or destroyed by, for example, high-ion bombardment or plasma arc. Summary of the Invention

[0005] One or more embodiments include a method for selectively depositing a thin film on a region of a stepped structure without performing a separate photolithography process, and more specifically, a method for improving etch selectivity without increasing the power of selectively depositing a thin film on a patterned structure (e.g., a stepped structure) without performing a photolithography process.

[0006] Other 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 practicing the embodiments presented in this disclosure.

[0007] According to one or more embodiments, a substrate processing method includes: supplying a first gas onto a structure; supplying a second gas to form a first thin film on the structure; forming a second material layer by supplying the first gas onto the first thin film; removing a portion of the second material layer to expose a portion of the first thin film; removing the exposed portion of the first thin film; and removing the second material layer.

[0008] According to an example of a substrate processing method, a first plasma can be applied during the supply of a second gas, and a second plasma can be applied during the formation of a second material layer.

[0009] According to another example of the substrate processing method, a first material layer can be formed on the structure during the supply of the first gas, and the second gas can be modified to be reactive with the first material layer by applying a first plasma.

[0010] According to another example of the substrate processing method, the first gas can be dissociated by applying a second plasma to form a second material layer.

[0011] According to another example of the substrate processing method, the removal of a portion of the second material layer and the removal of the exposed portion of the first thin film can be performed by isotropic etching.

[0012] According to another example of the substrate processing method, the same etchant can be used to remove a portion of the second material layer and the exposed portion of the first film.

[0013] According to another example of the substrate processing method, the second plasma may include a directional plasma, and the properties of the second material layer may be partially altered by the second plasma.

[0014] According to another example of the substrate processing method, during isotropic etching, the remainder of the second material layer is used as a mask, such that a portion of the first film under the second material layer is retained, and the remainder of the first film can be removed.

[0015] According to another example of the substrate processing method, the frequency of the first power supplied during the application of the first plasma can be greater than the frequency of the second power supplied during the application of the second plasma.

[0016] According to another example of the substrate processing method, the first gas may include a silicon source containing carbon, and the second material layer may include silicon and carbon.

[0017] According to another example of the substrate processing method, the first thin film may include at least one of silicon oxide or silicon nitride, and the second material layer may further include oxygen or nitrogen.

[0018] According to another example of the substrate processing method, the second material layer may have etch selectivity relative to the first thin film.

[0019] According to another example of the substrate processing method, the second material layer may include carbon elements, and the WER of hydrogen fluoride (HF) in the first thin film may be greater than the WER of hydrogen fluoride in the second material layer.

[0020] According to another example of the substrate processing method, for a specific etchant, a first portion of the second material layer has a first WER, a second portion of the second material layer has a second WER greater than the first WER, and the first thin film may have a third WER greater than the second WER.

[0021] According to another example of the substrate processing method, the substrate processing method may also include trimming the first thin film.

[0022] According to another example of the substrate processing method, trimming of the first film may include removing protrusions from the first film.

[0023] According to one or more embodiments, a substrate processing method includes: supplying a silicon-containing source gas onto a structure to form a first silicon-containing material layer adsorbed on the structure; forming a first thin film on the structure by supplying a reactive gas that reacts with the silicon-containing source gas; supplying the silicon-containing source gas onto the first thin film and applying a directional plasma to form a second silicon-containing material layer adsorbed on the first thin film, wherein the second silicon-containing material layer is partially densified or weakened by the directional plasma; exposing a portion of the first thin film by performing isotropic etching on the second silicon-containing material layer; removing the exposed portion of the first thin film; and performing isotropic etching to remove the second silicon-containing material layer.

[0024] According to one or more embodiments, a substrate processing method includes: structurally forming a first thin film; forming a material layer on the first thin film with a wet etch resistance greater than that of the first thin film; removing a portion of the material layer using wet etching to expose a portion of the first thin film; and removing the exposed portion of the first thin film.

[0025] According to an example of a substrate processing method, the formation of a material layer may include forming a material layer adsorbed on a first thin film by supplying a first gas.

[0026] According to another example of the substrate processing method, during the formation of the first thin film, the first gas used in the formation of the material layer can be used. Additionally, during the formation of the material layer, the first gas used in the formation of the first thin film can also be used. Attached Figure Description

[0027] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0028] Figures 1 to 7 This is a flowchart of a substrate processing method according to an embodiment of the present invention;

[0029] Figure 8 This is a flowchart of a substrate processing method according to an embodiment of the present invention;

[0030] Figure 9 This is a flowchart of a substrate processing method according to an embodiment of the present invention;

[0031] Figure 10 This is a process flow diagram of a substrate processing method according to an embodiment of the present invention;

[0032] Figure 11 Is execution Figure 10 A schematic diagram of the process;

[0033] Figure 12 It is shown Figure 10 and 11 Views of embodiments of the first and second steps; and

[0034] Figure 13 yes Figure 10 and 11 A detailed view of the fifth step of the process. Detailed Implementation

[0035] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings, wherein the same reference numerals always refer to the same elements. In this respect, the embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, the embodiments are described below only with reference to the accompanying drawings to explain various aspects of this specification. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one” modify the entire list of elements when preceding it, without modifying any individual element in the list.

[0036] In the following description, one or more embodiments will be described more fully with reference to the accompanying drawings.

[0037] In this respect, this embodiment may take different forms and should not be construed as 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.

[0038] The terminology used herein is for the purpose of describing particular embodiments and not for the purpose of limiting this disclosure. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms “comprising,” “including,” and variations thereof, as used herein, specify the presence of the stated feature, integer, step, process, component, part, and / or group 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.

[0039] It should be understood that although the terms first, second, etc., are used herein to describe various components, parts, regions, layers, and / or portions, these components, parts, regions, layers, and / or portions should not be limited by these terms. These terms do not indicate any order, number, or importance, but are merely used to distinguish individual components, regions, layers, and / or portions. Therefore, without departing from the teachings of the embodiments, the first component, part, region, layer, or portion discussed below may be referred to as the second component, part, region, layer, or portion.

[0040] In this disclosure, "gas" can include evaporated solids and / or liquids, and can include a single gas or a mixture of gases. In this disclosure, the process gas introduced into the reaction chamber via a spray head can include precursor gases and additive gases. Precursor gases and additive gases can typically be introduced as a mixed gas or can be introduced separately into the reaction space. Precursor gases can be introduced together with a carrier gas, such as an inert gas. Additive gases can include diluent gases, such as reactant gases and inert gases. Reactant gases and diluent gases can be introduced into the reaction space mixed or separately. Precursors can include two or more precursors, and reactant gases can include two or more reactant gases. Precursors can be gases chemisorbed onto the substrate and typically contain metalloid or metallic elements constituting the main structure of the dielectric film matrix, and the reactant gas used for deposition can be a gas that reacts with the precursor chemisorbed onto the substrate when excited to immobilize an atomic layer or monolayer onto the substrate. The term "chemisorbed" can refer to chemically saturated adsorption. Gases other than process gases, i.e., gases not introduced via a spray head, can be used to seal the reaction space, and can include sealing gases, such as inert gases. In some embodiments, the term "membrane" may refer to a layer that extends continuously in a direction perpendicular to the thickness direction and is substantially free of pinholes to cover the entire target or related surface, or it 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 a non-membrane structure. A membrane or layer may include discrete single membranes or layers or multiple membranes or layers having some characteristics, and the boundaries between adjacent membranes or layers may be clear or unclear, and may be defined based on physical, chemical and / or some other characteristics, formation process or sequence, and / or the function or purpose of adjacent membranes or layers.

[0041] In this disclosure, the phrase "containing Si-N bonds" can refer to having one or more Si-N bonds, having a main framework substantially composed of one or more Si-N bonds, and / or having substituents substantially composed of one or more Si-N bonds. The silicon nitride layer can be a dielectric layer containing Si-N bonds, and can include both a silicon nitride layer (SiN) and a silicon oxynitride layer (SiN).

[0042] In this disclosure, the term "same material" should be interpreted as meaning that the main components (composition) are the same. For example, when both the first layer and the second layer are 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 group above, but its specific film quality may differ from that of the first layer.

[0043] Furthermore, in this disclosure, since the operable range can be determined based on routine work, any two variables can constitute the operable range of a variable, and any indicated range can include or exclude endpoints. Additionally, the value of any indicated 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, median, representative value, multi-value, etc.

[0044] In the disclosures that do not specify conditions and / or structures, those skilled in the art can readily provide these conditions and / or structures as routine experiments based on the disclosures. In all described embodiments, any component used in the embodiments can be replaced by any of its equivalents, including those components explicitly, necessary, or substantially described herein for intended purposes. Furthermore, this disclosure can be similarly applied to devices and methods.

[0045] In the following description, embodiments of the present disclosure will be illustrated with reference to the accompanying drawings. In the drawings, variations in the illustrated shapes may be expected as a result of, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the present disclosure should not be construed as limited to specific shapes within the areas shown herein, but may include, for example, shape deviations resulting from the manufacturing process.

[0046] Figures 1 to 7 This is a flowchart of a substrate processing method according to an embodiment of the present invention.

[0047] refer to Figure 1 A stepped structure 10 is provided. The stepped structure 10 may be on a substrate (not shown). The stepped structure 10 may include one or more layers. For example, compared to a stacked structure comprising multiple layers, the stepped structure 10 may be formed by reactive ion etching and / or resist thinning.

[0048] When forming the stepped structure 10, the stepped structure 10 has an upper surface U, a lower surface L, and a side surface S connecting the upper surface U to the lower surface L. For example, the stepped structure 10 may include at least one step, and the at least one step may have an upper surface U, a lower surface L, and a side surface S connecting the upper surface U to the lower surface L.

[0049] Although a stepped structure 10 is shown in this embodiment and a substrate processing method is described based on it, the inventive concept is not limited thereto. For example, the substrate processing method according to embodiments of the inventive concept can be used for selective deposition of any type of three-dimensional (3D) structure. For example, selective deposition of patterned structures including multiple protrusions can be achieved.

[0050] When the stepped structure 10 is provided, at least one thin film is formed on the stepped structure 10. The thin film can be formed by any kind of deposition process (e.g., deposition processes such as sputtering, chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD)). For example, a first material layer 20 can be formed by supplying a first gas to the structure. Figure 1 ), and supply a second gas to structurally form a first thin film 30 ( Figure 2 The first material layer 20 and the second gas can react to form the first thin film 30.

[0051] For example, the first thin film 30 may be a silicon oxide film, a silicon nitride film, or a silicon oxynitride film. The first gas used to form the first thin film 30 may include a silicon-containing source gas. Therefore, a silicon-containing source gas may be supplied to the structure to form a silicon-containing material layer chemically adsorbed onto the structure.

[0052] For example, the first gas may contain methyl (-C) n H 2n+1 ) or ethyl(-C n H 2n+2 The first gas is a silicon-containing source gas based on aminosilane. That is, the first gas may include a silicon source containing carbon. Therefore, the material layer formed from the first gas may include both silicon and carbon. As will be described below, the material layer including carbon can have good etch selectivity for silicon oxide or silicon nitride.

[0053] In some embodiments, an ALD process can be used to form the first thin film 30. For example, a basic cycle of source supply, source purging, reactant supply, and reactant purging can be repeated multiple times to form the first thin film 30 with a desired thickness. In this case, a first gas is supplied during source supply to form the first material layer 20, and a second gas is supplied during reactant supply to form the first thin film 30.

[0054] In an alternative embodiment, energy can be applied to promote the reaction between the first material layer 20 and the second gas. For example, a first plasma can be applied during the supply of the second gas. By applying energy such as the first plasma, the second gas can be altered (e.g., excited) to react with the first material layer 20. Thus, the second gas and the first material layer 20 can react to form the first thin film 30.

[0055] Reference Figure 3 The second material layer 40 is formed by supplying a first gas onto the first thin film 30. The supply of the first gas onto the first thin film 30 can be repeated multiple times. For example, a cycle including supplying and purging the first gas can be performed multiple times. By repeating this cycle, a second material layer 40 of the desired thickness can be formed.

[0056] The second material layer 40 may have different chemical properties than the first thin film 30. More specifically, the wet etching resistance of the second material layer 40 may be higher than that of the first thin film 30. Therefore, when performing wet etching of the first thin film 30 and the second material layer 40, the amount of the first thin film 30 removed may be greater than the amount of the second material layer 40 removed. Thus, the second material layer 40 can be used as an etching mask during the etching process of the first thin film 30.

[0057] The gas supplied during the formation of the second material layer 40 can be the same as the gas supplied during the formation of the first thin film 30. That is, a first gas comprising a silicon source containing carbon can be supplied simultaneously with the formation of the second material layer 40. Therefore, the second material layer 40 may comprise silicon and carbon.

[0058] The carbon element included in the second material layer 40 can reduce the wet etching rate (WER) of hydrogen fluoride (HF). Therefore, when using HF to wet etch the first thin film 30 and the second material layer 40, the WER of HF used for the carbon-free first thin film 30 may be greater than the WER of HF used for the carbon-containing second material layer 40.

[0059] The second material layer 40 may be a material layer adsorbed on the first thin film 30. For example, the first gas used to form the second material layer 40 may include the source gas used in the ALD process. In this case, the second material layer 40 can be formed by chemically adsorbing the first gas onto the first thin film 30.

[0060] In some embodiments, the second material layer 40 formed on the first thin film 30 may include at least a portion of the components of the first thin film 30. For example, when the first thin film 30 comprises silicon oxide, the second material layer 40 may include oxygen. In another example, when the first thin film 30 comprises silicon nitride, the second material layer 40 may include nitrogen.

[0061] In some embodiments, a second plasma may be applied simultaneously with the supply of a first gas to form the second material layer 40. In conventional ALD processes, plasma is not applied during the supply of the source gas. However, it is noted that in embodiments conceived according to the present invention, plasma is applied during the supply of the source gas. The first gas can be dissociated by the application of the second plasma, thus promoting the formation of the second material layer 40.

[0062] In some embodiments, the application of the second plasma may be performed after the supply of the first gas. In other words, the application of the second plasma may include a single cycle to form the second material layer 40. Hereinafter, it is assumed that the supply of the first gas and the application of the second plasma, which are included in the formation of the second material layer 40, are performed sequentially.

[0063] Figure 4 The application of a second plasma is illustrated. The second plasma can partially alter the properties of the second material layer 40. For example, the second plasma can be directional. As an example, the second plasma can be applied to face the upper and lower surfaces of the second material layer 40, so that the properties of the upper surface portion 40U and the lower surface portion 40L of the second material layer 40 can be altered by applying a directional second plasma.

[0064] In some embodiments, the process conditions for applying the first plasma to form the first thin film 30 may differ from the process conditions for applying the second plasma. For example, the frequency of the first power supplied during the application of the first plasma may be greater than the frequency of the second power supplied during the application of the second plasma. By applying the second plasma at a relatively low frequency, the linearity (i.e., directionality) of the ions can be improved.

[0065] In one example, the application of a directional second plasma can densify portions of the second material layer located on the upper and lower surfaces of the stepped structure 10. In another example, the application of a directional second plasma can weaken portions of the second material layer located on the upper and lower surfaces of the stepped structure 10. This change in property can be achieved by adjusting parameters (e.g., power) during plasma treatment. In the following description, the upper surface portion 40U and the lower surface portion 40L of the second material layer 40 will be densified due to the application of plasma.

[0066] refer to Figure 5 A portion of the second material layer 40 is removed to expose a portion of the first thin film 30. A first isotropic etching process, such as wet etching, can be used to remove the second material layer 40. While the upper surface portion 40U and the lower surface portion 40L of the second material layer 40 are densified due to the directional application of a second plasma, during the first isotropic etching, the side portion 40S of the second material layer 40 ( Figure 4 The first isotropic etching is removed, while the upper surface portion 40U and the lower surface portion 40L of the second material layer 40 can be retained. Therefore, after the first isotropic etching, the side surface portion 30S of the stepped structure 10 of the first thin film 30 is exposed, while the upper surface portion 30U and the lower surface portion 30L of the stepped structure 10 of the first thin film 30 can be covered by the second material layer 40.

[0067] Subsequently, refer to Figure 6The exposed portion of the first thin film 30 is removed. For example, after the first isotropic etching, a second isotropic etching can be performed on the structure. During the second isotropic etching, the remaining portions 40U and 40L of the second material layer 40 can act as an etching mask. Therefore, portions 30U and 30L of the first thin film under the second material layer 40 remain unetched, while the remaining portion of the first thin film 30 (i.e., the exposed portion 30S) can be removed to expose the surface of the stepped structure 10.

[0068] In some embodiments, the removal of a portion 40S of the second material layer 40 and the removal of the exposed portion 30S of the first thin film 30 can be performed simultaneously. For example, in other words, the removal of a portion 40S of the second material layer 40 and the removal of the exposed portion 30S of the first thin film 30 can be performed by a single etching process. That is, the first isotropic etching and the second isotropic etching can be the same etching process.

[0069] For example, for a specific etchant, the dense portion of the second material layer 40 (the upper surface portion 40U and the lower surface portion 40L of the stepped structure 10) may have a first WER, the non-dense portion of the second material layer 40 (the side portion 40S of the stepped structure 10) may have a second WER greater than the first WER, and the first thin film 30 may have a third WER greater than the second WER.

[0070] In this case, a specific etchant can be used to perform isotropic etching of the first thin film 30 and the second material layer 40. First, the second material layer 40 is exposed to the etchant such that the upper surface portion 40U and the lower surface portion 40L of the second material layer 40, which have the lowest value of the first WER, can be retained, while the side portion 40S of the second material layer 40, which has a relatively higher value of the second WER, can be removed.

[0071] Because isotropic etching is performed continuously using an etchant, the upper surface portion 40U and lower surface portion 40L of the second material layer 40 with the lowest value of the first WER, as well as the upper surface portion 30U and lower surface portion 30L of the first thin film 30 below the upper surface portion 40U and lower surface portion 40L, are retained, while the exposed portion of the first thin film 30 with the highest value of the third WER, namely the side surface portion 30S of the stepped structure 10, can be removed.

[0072] In alternative embodiments, the first isotropic etching and the second isotropic etching can be different etching processes. For example, removing portion 40S of the second material layer 40 using the first isotropic etching and removing the exposed portion 30S of the first thin film 30 using the second isotropic etching can be performed using different types of etchants. As another example, the first and second isotropic etchings can be performed using the same type of etchant, but at least some process parameters can be different.

[0073] Reference Figure 7 The remaining second material layer 40 after isotropic etching is removed. An anisotropic etching process, such as dry etching, can be used to remove the remaining second material layer 40. By removing the second material layer 40, the first thin film 30 partially formed on the upper and lower surfaces of the stepped structure 10 can be exposed.

[0074] like Figure 7 As shown, the exposed first film 30 may include a protrusion 50. The protrusion 50 may have a shape that protrudes from the side surface S of the stepped structure 10. To eliminate this protrusion shape, the first film 30 may be trimmed. In some embodiments, a sputtering process may be performed during the trimming of the first film 30. In another embodiment, any further processing of the first film 30 (e.g., annealing) may be performed during the trimming of the first film 30.

[0075] Figure 8 This is a flowchart of a substrate processing method according to an embodiment of the present invention. 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, the embodiments will not be described again.

[0076] refer to Figure 8 In operation 810, a silicon-containing source gas is supplied to the structure (e.g., a stepped structure). A first silicon-containing material layer can be formed by adsorbing the silicon-containing source gas onto the structure. In operation 820, after the first silicon-containing material layer is formed, any remaining source gas is purged.

[0077] Subsequently, in operation 830, a reactant gas is supplied to react with the silicon-containing source gas. Because the first silicon-containing material layer adsorbed on the structure reacts with the reactant gas, a first thin film can be formed on the structure. In operation 840, after the first thin film is formed, any remaining reactant gas is purged.

[0078] In operation 850, when forming the first thin film, a silicon-containing source gas is supplied onto the first thin film to form a second silicon-containing material layer adsorbed on the first thin film. A directional plasma can be applied simultaneously with the supply of the silicon-containing source gas, and the second silicon-containing material layer can be partially densified or weakened by the directional plasma.

[0079] Subsequently, in operation 860, a first isotropic etching is performed on the second silicon-containing material layer to partially remove the second silicon-containing material layer. The first thin film can be partially exposed by the first isotropic etching. Because the properties of the second silicon-containing material layer are partially altered by the directional plasma, the patterning of the second silicon-containing material layer can be achieved solely by isotropic etching without a separate photolithography process, and the first thin film can be partially exposed.

[0080] Subsequently, in operation 870, the exposed portions of the first thin film are removed. For example, isotropic etching can be performed on the exposed portions of the first thin film using a second isotropic etching. Because the second silicon-containing material layer exists on the unexposed portions of the first thin film, the unexposed portions of the first thin film can be retained after the second isotropic etching. Therefore, the patterning of the first thin film can be achieved solely through isotropic etching, without requiring a separate photolithography process.

[0081] Subsequently, in operation 880, the second silicon-containing material layer is removed. For example, anisotropic etching can be used to remove the second silicon-containing material layer.

[0082] According to embodiments of the inventive concept described above, because a relatively thin material layer adsorbed (e.g., chemisorption) by the source gas is formed on the thin film to be patterned (i.e., the first thin film), and selective densification / weakening is performed on the material layer without using direct selective densification / weakening of the thin film to be patterned, the thin film can be selectively deposited on the patterned structure (e.g., the stepped structure) without requiring a photolithography process and without increasing power.

[0083] Figure 9 This is a flowchart of a substrate processing method according to an embodiment of the present invention. 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, the embodiments will not be described again.

[0084] refer to Figure 9 In operation 910, a first thin film is structurally formed. The first thin film can be formed by any type of deposition process (e.g., deposition processes such as sputtering, CVD, PVD, and ALD), and a first gas can be used during the deposition process. In one example, the first gas may include components of the first thin film. In another example, the first gas may include elemental components resistant to etchants used in subsequent etching processes.

[0085] Subsequently, in operation 920, a material layer with greater resistance to wet etch than the first thin film is formed on the first thin film. For example, a material layer with a lower WER than the first thin film can be formed. The formation of the material layer may include forming the material layer adsorbed on the first thin film by supplying a first gas. In other words, the first gas used in the formation of the first thin film can be used during the formation of the material layer.

[0086] In operation 930, partial densification or weakening of the material layer is performed after or during its formation. By applying a certain amount of energy (e.g., plasma) to the material layer, its properties can be partially altered. In this case, the WER of the material layer can also be partially changed.

[0087] Subsequently, in operation 940, wet etching is used to pattern the first thin film. More specifically, wet etching is performed on a material layer having partially different WER properties, such that a portion of the material layer can be removed, thus exposing a portion of the lower part of the material layer. The exposed portion of the first thin film is then removed by continuous wet etching, thereby patterning the first thin film.

[0088] In addition to the embodiments described above, this disclosure provides a method for increasing the etching selectivity of the upper and side portions of a low-corrosion-resistant material deposited on a patterned structure. Figure 10 This is a process flow diagram based on the substrate processing method of this disclosure. Figure 11 Is execution Figure 10 A schematic diagram of the process.

[0089] First step 101: In this step, a first thin film 2 is uniformly deposited on the surface of the patterned structure 1 to form a conformal film. The thin film deposition is performed by the PEALD method, and precursor, purge gas and reactive gas are alternately supplied to activate at least one gas by plasma.

[0090] Step 201: In this step, a second thin film 3 is deposited on the first thin film as a mask layer. The second thin film 3 is formed by plasma dissociation of precursor molecules, simultaneously supplying only the precursor and purge gas without supplying the reactant gas. The dissociated precursor molecules are deposited on the first thin film 2. Because the second thin film 3 has different wet etch resistance than the first thin film 2 and no reactant gas is supplied, the film is not formed by chemical bonding between heterogeneous elements, and the dissociated precursor constituent elements are densified by free radicals. That is, in this step, a mask layer with different etch resistance is introduced to increase selectivity.

[0091] Third step 301: In this step, the film is selectively removed by wet etching. Specifically, in the second step, the first and second films on the upper and lower surfaces of the second film (mask layer) are retained, which are densified by the ion bombardment effect and simultaneously resist etching, while the less dense second and first films on the side surfaces are removed. For example, wet etching is performed using a 100:1 hydrofluoric acid (HF) solution.

[0092] Step 401: In this step, the second film on the upper and lower surfaces is removed. The removal of the second film is performed by dry etching. A fluorine (F)-containing etching gas, such as C, is used. x F 2x Remove the second film.

[0093] Step 501: In this step, the protrusions 4 remaining on the edge of the upper surface are removed. The removal of the protrusions 4 is performed by a sputtering process. For example, to improve the straightness of the ions, a low-frequency Ar plasma is supplied to remove the protrusions 4.

[0094] Figure 12 It is shown Figure 10 and 11 A view of an embodiment of the first and second steps. Figure 12 In the first step, Si source gas, oxygen reactant gas, Ar purge gas, and plasma are sequentially supplied to a substrate to deposit a first SiO2 thin film on a patterned structure on the substrate. This step is repeated multiple times (m cycles) to uniformly form a first thin film with a thickness of 300 Å on the pattern. Subsequently, in the second step, a second thin film is deposited on the first thin film. In the second thin film, no oxygen reactant gas is supplied, and Si source gas, Ar purge gas, and plasma are sequentially supplied as a cycle repeated multiple times (n cycles), and a second thin film with a thickness of 30 Å is deposited on the upper surface of the pattern. In step 2, because there is no reactant gas, the Si source gas is deposited on the first thin film while being dissociated by Ar radicals. In embodiments of this disclosure, a carbon-containing Si source is used, such as one containing methyl (-C) groups. n H 2n+1 ) or ethyl(-C n H 2n+2 The second film deposited on the first film comprises Si and C components. Furthermore, the second film may include oxygen. For example, some oxygen from O2-terminated sites or dangling bonds of the first film in contact with the second film may be included in the second film. Therefore, the second film may include a small amount of oxygen. A second film comprising both carbon and oxygen components may be represented as Si(O)C.

[0095] As described above, because the second film is not formed through chemical bonding between heterogeneous elements, its bonding strength may be weaker than that of the first film. Therefore, the film is densified while plasma is supplied. Furthermore, since the second film is not formed through chemical bonding, the thickness of the second film on the patterned side is less than the thickness of the second film on the patterned surface. Additionally, the second film on the patterned side also experiences a small densification effect from the plasma. Therefore, the wet etching resistance of the second film on the patterned side is lower than that of the second film on the patterned surface. On the other hand, because the second film on the patterned surface is arranged on the patterned surface in a direction perpendicular to the free radical direction, the second film is densified by plasma and has strong wet etching resistance. As described above, according to embodiments of the present invention, second films with different wet etching resistances can be selectively formed.

[0096] Table 1 below shows an example of the process conditions for the first step described above.

[0097] Table 1

[0098]

[0099] Table 2 below shows an example of the process conditions for the second step described above.

[0100] Table 2

[0101]

[0102] The RF power applied in the first step of Table 1 and the second step of Table 2 can remain the same. That is, it is not necessary to increase the RF power in the second step to increase the etch selectivity of the thin films on the upper and side surfaces of the pattern. This is because etch selectivity can be increased by introducing two thin films with different wet etch resistances, as described below. Therefore, the technical effect of the substrate processing method according to this disclosure is that it can prevent problems such as increased fatigue of the substrate processing equipment due to increased applied RF power, for example, damage to components constituting the substrate processing equipment and a reduction in the uptime of the substrate processing equipment.

[0103] The RF frequency of the RF power applied in the second step of Table 2 can remain the same as in step 1, but in another embodiment, a relatively low frequency RF power can be applied in the second step. Low-frequency RF power has a lower ion density compared to high-frequency RF power, but has the technical effect of further increasing the density of the second thin film on the patterned surface because ion linearity is improved. Preferably, an RF frequency of about 300 kHz to about 500 kHz can be applied.

[0104] exist Figure 10 In the third step 301, wet etching is performed for 3 minutes in an HF solution diluted to 100:1. Table 3 below shows the wet HF etch resistance of the first SiO2 film and the second Si(O)C film according to this disclosure. The etch resistance below was measured by depositing each film on a flat substrate under the conditions shown in Tables 1 and 2, and etching each film for 3 minutes in an HF solution diluted to 100:1.

[0105] Table 3

[0106]

[0107] As shown in Table 3, the second Si(O)C film exhibits significantly greater resistance to wet HF etching than the first SiO2 film. Since carbon (C) is known to have strong resistance to HF etching, a precursor containing carbon is introduced, allowing the second film to contain carbon. As described above, the substrate processing method according to this disclosure achieves the technical advantage of further improving the etching selectivity of the upper and side surfaces of the pattern without increasing the RF power by introducing two films with different wet HF resistances or elements with strong HF resistance.

[0108] Furthermore, as described above, since the second film on the pattern side surface is less dense than the second film on the pattern top surface, it has the technical effect of promoting the etching of the first and second films on the pattern side surface compared to the first and second films on the pattern top surface.

[0109] Table 4 below shows Figure 11 The etching conditions for the fourth and fifth steps.

[0110] Table 4

[0111]

[0112] Figure 13 This is a detailed view of the fifth step of the process. (Refer to...) Figure 13 Argon radicals physically remove protrusions from the first thin film, such as the SiO2 film on the patterned surface. To enhance the sputtering effect, Ar gas, which is heavier than other elements, is supplied, and low-frequency RF power is supplied to enhance the linearity of the radicals. After sputtering, the protrusions are removed, and depending on the magnitude and duration of the applied RF power, a portion of the first thin film on the patterned surface can be etched (see [link to sputtering process]). Figure 13 (The dashed line in the image). In addition, a portion of the upper surface of the first SiO2 film on the patterned surface can be etched together due to sputtering.

[0113] According to this disclosure, in order to improve the etch selectivity of a first thin film deposited on a pattern, a second thin film having different wet etch resistance than the first thin film is formed on the first thin film as a mask layer. In embodiments according to this disclosure, the second thin film has higher wet etch resistance than the first thin film and has the technical effect of improving the etch selectivity of the upper and side portions of the pattern without increasing the RF power.

[0114] Furthermore, the substrate processing method according to this disclosure has the technical effect of preventing increased fatigue of the substrate processing equipment due to the application of high RF power.

[0115] Furthermore, in embodiments according to this disclosure, by selectively forming a film with strong resistance to wet etching on the upper surface of the pattern compared to the side surface of the pattern, the substrate processing method has the technical effect of further accelerating the etching rate of the film on the side surface.

[0116] Furthermore, the substrate processing method according to this disclosure has the technical effect of achieving selective etching of the thin film on the upper and side surfaces of the pattern and physically removing the protrusions of the thin film on the upper surface of the pattern by applying a sputtering method to the protrusions of the thin film.

[0117] It should be understood that the embodiments described herein should be considered descriptive only and not for limiting purposes. The description of features or aspects in each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as defined by the appended claims.

Claims

1. A substrate processing method, comprising: The first gas is supplied to the structure; A second gas is supplied to form a first thin film on the structure; The second material layer is formed by supplying a first gas onto the first thin film; Remove a portion of the second material layer to expose a portion of the first film; Remove the exposed portion of the first film; Remove the second material layer; as well as Trim the first film. The trimming of the first film includes removing protrusions from the first film by a sputtering process using low-frequency Ar plasma.

2. The substrate processing method according to claim 1, wherein The first plasma is applied during the supply of the second gas, and A second plasma is applied during the formation of the second material layer.

3. The substrate processing method according to claim 2, wherein During the supply of the first gas, a first material layer is formed on the structure, and By applying the first plasma, the second gas is altered to have reactivity with the first material layer.

4. The substrate processing method according to claim 2, wherein The first gas is dissociated by applying the second plasma to form the second material layer.

5. The substrate processing method according to claim 2, wherein The removal of the portion of the second material layer and the removal of the exposed portion of the first film are performed by isotropic etching.

6. The substrate processing method according to claim 5, wherein, The removal of the portion of the second material layer and the removal of the exposed portion of the first film are performed using the same etchant.

7. The substrate processing method according to claim 5, wherein The second plasma includes directional plasma, and The properties of the second material layer are partially altered by the second plasma.

8. The substrate processing method according to claim 7, wherein During the isotropic etching, the remaining portion of the second material layer is used as a mask, such that a portion of the first film beneath the second material layer is retained, and the remaining portion of the first film is removed.

9. The substrate processing method according to claim 2, wherein The frequency of the first power supplied during the application of the first plasma is greater than the frequency of the second power supplied during the application of the second plasma.

10. The substrate processing method according to claim 1, wherein, The first gas includes a silicon source containing carbon, and The second material layer comprises silicon and carbon.

11. The substrate processing method according to claim 10, wherein The first thin film further includes at least one of silicon oxide and silicon nitride, and The second material layer also contains oxygen or nitrogen.

12. The substrate processing method according to claim 1, wherein, The second material layer has etch selectivity relative to the first thin film.

13. The substrate processing method according to claim 12, wherein The second material layer comprises carbon elements, and The wet etching rate of hydrogen fluoride in the first thin film is greater than the wet etching rate of hydrogen fluoride in the second material layer.

14. The substrate processing method according to claim 1, wherein Compared to a specific etchant, The first portion of the second material layer has a first wet etching rate. The second portion of the second material layer has a second wet etch rate greater than the first wet etch rate, and The first film has a third wet etching rate that is greater than the second wet etching rate.

15. A substrate processing method, comprising: A silicon-containing source gas is supplied structurally to form a first silicon-containing material layer adsorbed on the structure; A reaction gas is supplied to react with a silicon-containing source gas to form a first thin film on the structure; A silicon-containing source gas is supplied on a first thin film, and a directional plasma is applied to form a second silicon-containing material layer adsorbed on the first thin film, wherein the second silicon-containing material layer is partially densified or weakened by the directional plasma; An isotropic etching is performed on the second silicon-containing material layer to expose a portion of the first thin film; Remove the exposed portion of the first film; Perform isotropic etching to remove the second silicon-containing material layer; and Trim the first film. The trimming of the first film includes removing protrusions from the first film by a sputtering process using low-frequency Ar plasma.

16. A substrate processing method, comprising: The first thin film is formed structurally; A material layer with greater resistance to wet etching than the first film is formed on the first film; A portion of the material layer is removed using wet etching to expose a portion of the first thin film; Remove the exposed portion of the first film; as well as Trim the first film. The trimming of the first film includes removing protrusions from the first film by a sputtering process using low-frequency Ar plasma.

17. The substrate processing method of claim 16, wherein, The formation of the material layer includes forming a material layer adsorbed on the first film by supplying a first gas.

18. The substrate processing method of claim 16, wherein, During the formation of the material layer, the first gas used in the formation of the first film is used.

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