Selective Etching of Substrate

Abstract

This specification describes a method for selectively cleaning and / or etching a sample. The method includes selectively forming a film in a trench of a substrate such that the trench can be selectively etched. The polymer film is deposited on the bottom surface of the trench without being deposited on the sidewalls. A second film is selectively formed in the trench without forming the second film on the polymer film. Thereafter, the polymer is removed from the bottom surface of the trench, and then etching is performed on the bottom surface of the trench using an etching chemical. The second film protects the sidewalls from etching.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to a method for etching a substrate, in which a flowable polymer film is used to enable improvement of etching selectivity between different regions of the substrate.

Background Art

[0002]

[0002] In the semiconductor industry, devices are manufactured by numerous manufacturing processes. In this manufacturing process, structures with increasingly reduced sizes are being produced. As the shape of the device shrinks, it has become more difficult to control process uniformity and device reproducibility, especially in upstream processes.

[0003]

[0003] Integrated circuits can be realized by a process of fabricating a complexly patterned material layer on a substrate surface. To generate a patterned material on the substrate, a controlled method of forming and removing the exposed material is used. For example, in a gap filling process, materials can be formed or deposited to fill trenches or other features formed on a semiconductor substrate. Characteristics of the trenches or features can include a high aspect ratio and reduced critical dimensions, and thus the filling process can be difficult. For example, since deposition can occur at the top of the trench or feature and along the sidewalls of the trench or feature, continued deposition may cause the trench or feature (including between the sidewalls within the trench or feature) to be pinched off, resulting in the generation of voids. This may affect the performance of the device and subsequent processing steps.

[0004]

[0004] In the current etching process, the substrate can be composed of silicon and silicon nitride. When the substrate is exposed to air, it may have a bottom containing silicon dioxide (SiO) and sidewalls of silicon oxynitride (SiON). With the miniaturization of devices, the target etching parameters are also decreasing. To address this problem, selective etching or selective chemical passivation is preferred. Since the bottom and sidewalls contain similar materials (SiO and SiON), it is difficult to apply selective etching or selective chemical passivation. Therefore, it is necessary to improve the selective etching of the substrate so that smaller target etching parameters can be achieved.

Summary of the Invention

[0005]

[0005] In some embodiments of the present disclosure, a method for cleaning and etching a sample is provided. The method may include placing a substrate in a chamber. The substrate may include a layer in which at least one trench is formed. At least one trench of the method includes a top surface, a bottom surface, and at least one sidewall. In some embodiments, the method may include depositing a polymer film on the bottom surface of at least one trench without depositing the polymer film on at least one sidewall of at least one trench. In some embodiments, the method may include selectively forming a second film on the layer without forming the second film on the polymer film. In some embodiments, the method may include removing the polymer film from the bottom surface of at least one trench. In some embodiments, the method may further include etching the bottom surface of the trench using an etching chemical, where the second film protects at least one sidewall from the etching chemical.

[0006]

[0006] In some embodiments of the present disclosure, a method of cleaning and etching a substrate is provided. The method may include placing a substrate in a chamber. The substrate includes a layer in which at least one trench is formed, and the at least one trench has a top surface, a bottom surface, and at least one sidewall. The method further includes depositing a polymer film on the bottom surface of the at least one trench without depositing the polymer film on at least one sidewall of the at least one trench, and selectively forming a second film on the layer without forming the second film on the polymer film. The method further includes removing the polymer film from the bottom surface of the at least one trench and performing an etching process including applying ammonium fluoride to the substrate. The etching process of the method may selectively interact with the bottom surface of the at least one trench and may not interact with the top surface and the at least one sidewall.

[0007]

[0007] The present disclosure is illustrated by way of example and not limitation in the accompanying drawings, in which like reference numerals indicate like elements. Note that various references to "an" or "one" embodiment in the present disclosure are not necessarily to the same embodiment, and such references mean at least one.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

[0009]

[0014] In the manufacture of semiconductor devices, polymer films can be used in many structures and processes such as masking materials, etching-resistant materials, and trench filling materials, among other applications. More specific uses of polymer films include the formation of hot implant hard masks and metal gate (MG) cut hard masks, the manufacture of MG, and reverse stone patterning. The present disclosure includes the formation of a polymer film on a semiconductor substrate using a molecular layer deposition (MLD) method.

[0010]

[0015] Embodiments disclosed herein describe a method of selectively cleaning and / or selectively etching a substrate. The method of selectively cleaning / etching a substrate may include placing the substrate in a chamber. The substrate may include a layer in which at least one trench is formed, and the at least one trench has a top surface, a bottom surface, and at least one sidewall. The method for etching may include depositing a polymer film on the bottom surface of at least one trench without depositing the polymer film on at least one sidewall of the at least one trench. The method may further include selectively forming a blocking film on the layer without forming a blocking film on the polymer film. The blocking film may be formed using, for example, a self-assembled monolayer (SAM) deposition technique. The method may further include removing the polymer film from the bottom surface of the at least one trench and etching the bottom surface of the trench using an etching chemical. Here, the blocking film protects at least one sidewall from the etching chemical.

[0011]

[0016] By selectively coating one or more portions of a substrate using different membranes, the profile of the substrate can be improved, and the blowout of the critical dimensions of the trenches can be improved. By using self-assembled monolayers (SAMs), it has been found that the surface is blocked from being etched and / or the surface is protected from etching. By selectively protecting the surface from etching, it is possible to avoid blowout of critical dimensions (e.g., trench width or cross-sectional profile) while removing material (e.g., any oxidized surface) in the selective regions of the trenches. The inventors have discovered that the bottom surface of the trenches in the substrate is often oxidized. This generally has an adverse effect on the performance of the final product. To remove the oxidized surface, an etching process step can be performed. However, at this stage, since it may affect the profile of the substrate (e.g., trenches formed in or on the substrate), it is not necessary to etch all surfaces.

[0012]

[0017] Therefore, a SAM can be formed on the top surface, side surfaces, or a combination thereof to protect these surfaces from etching. The inventors have found that depositing a polymer film on the bottom surface of the trench prevents the formation of the SAM on the bottom surface and allows the SAM to be formed on the top surface, sidewall surfaces, or a combination thereof. In an embodiment, the SAM consists of a regular arrangement of organic molecules that spontaneously assemble and adsorb on the surface. These molecules typically consist of one or more moieties (head groups) that are affinity for the substrate and a relatively long, inert, linear portion.

[0013]

[0018] In an embodiment, a flowable polymer is deposited on a substrate, but the flowable polymer does not adhere to the sidewalls of the trenches and instead accumulates at the bottoms of the trenches. The flowable polymer may solidify or cure at the bottom of the surface of the trench without being formed on the sidewalls of the trench. Then, the SAM may not adhere to the polymer selectively deposited at the bottom of the trench. Thus, the polymer film at the bottom of the trench may be removed after the SAM is selectively formed (e.g., at all positions except the polymer at the bottom of the trench). The etching chemical may selectively etch the oxide on the bottom surface of the trench and / or may etch the bottom surface of the trench at a rate much faster than it etches the SAM. Thus, the SAM protects the sidewalls and / or the top of the trench from etching, and the etching may be performed selectively with respect to the bottom surface of the trench.

[0014]

[0019] By selectively etching or cleaning the surface of the trench of the substrate without etching the other surfaces of the trench, it has been found that the variation in trench width with respect to the depth of the trench of the etched sample (i.e., the substrate) is reduced compared to conventional plasma etching processes. In this way, the inventors have found a method for selectively cleaning or etching the bottom surface of the trench without or with little etching of the top and / or sidewalls of the trench.

[0015]

[0020] In an embodiment, since the SAM and the polymer film have different chemical reactivities, the SAM can be selectively formed on a surface other than the polymer film. Thus, in accordance with aspects of the present disclosure, the SAM can react with a surface having no polymer film.

[0016]

[0021] Embodiments of a method for selectively cleaning or etching a substrate are disclosed herein that include depositing a polymer film and selectively forming a second film on the substrate. The polymer film is then removed and the substrate is etched until a target amount of the substrate is etched. When the second film is formed on the substrate, the polymer film can be deposited on the bottom surface of at least one trench of the substrate so that the second film is not formed on the bottom surface by the polymer film. It has been found that the polymer film and the second film can have different chemical reactivities to control the selectivity of film deposition and / or formation.

[0017]

[0022] As used herein, the term "substrate" refers to the surface or a portion of the surface on which the process acts. When reference is made to a substrate, it should be understood by those skilled in the art that it may refer to only a portion of the substrate, unless the context clearly indicates otherwise. Further, when reference is made to deposition onto a substrate, it can mean both a bare substrate and a substrate on which one or more films or features have been deposited or formed.

[0018]

[0023] The substrate as used herein may also refer to any substrate or material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, the substrate surface on which processing can be performed includes, depending on the application, silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, silicon germanium, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. The substrate includes, but is not limited to, semiconductor wafers.

[0019]

[0024] The substrate may be exposed to a pre-treatment process (a process of polishing, etching, reducing, oxidizing, hydroxylation (or a process of otherwise generating or grafting target chemical moieties to impart chemical functionality), annealing, and / or baking) of the substrate surface. In addition to directly performing film treatment on the surface of the substrate itself, in the present disclosure, any of the disclosed film treatment steps may be performed on a lower layer formed on the substrate, as will be disclosed in more detail below. The term "substrate surface" is intended to include such a lower layer as the context indicates. Thus, for example, when a film / layer or a partial film / layer is deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface. What a given substrate surface includes will depend on what films are deposited and the specific chemistry used. In one or more embodiments, the first substrate surface may be composed of metal, metal oxide, H-terminated Si x Ge 1-x and may be composed of a Si-containing dielectric, or vice versa. In some embodiments, the substrate surface may include specific functionality (e.g., -OH, -NH, etc.).

[0020]

[0025] Referring now to the drawings, FIG. 1 is a cross-sectional view of a processing chamber 100 (e.g., a semiconductor processing chamber) having one or more chamber components, according to an embodiment of the present disclosure. The processing chamber 100 can be used in processes where a corrosive plasma environment and / or corrosive chemicals are introduced. For example, the processing chamber 100 can be a chamber for a plasma etching reactor (also referred to as a plasma etcher). Examples of chamber components that can be exposed to plasma within the processing chamber 100 include a substrate support assembly 148, an electrostatic chuck (ESC), rings (e.g., a process kit ring or a single ring), chamber walls, a base, a showerhead 130, a gas distribution plate, a liner, a liner kit, a shield, a plasma screen, a flow equalizer, a cooling base, a chamber viewport, a chamber lid, nozzles, a process kit ring, and the like. In an embodiment, the processing chamber 100 is used to perform an etching process on a patterned substrate having a plurality of trenches formed therein.

[0021]

[0026] In one embodiment, the processing chamber 100 includes a chamber body 102 surrounding an internal space 106 and a showerhead 130. The showerhead 130 may or may not include a gas distribution plate. For example, the showerhead may be a multi-piece showerhead including a showerhead base and a showerhead gas distribution plate joined to the showerhead base. Alternatively, in some embodiments, the showerhead 130 may be replaced with a lid and nozzles, or in other embodiments, the showerhead 130 may be replaced with a plurality of pie-shaped showerhead compartments and a plasma generation unit. The chamber body 102 can be fabricated from aluminum, stainless steel, or other suitable materials. The chamber body 102 generally includes sidewalls 108 and a bottom 110. Any of the showerhead 130 (or lid and / or nozzles), sidewalls 108, and / or bottom 110 may include a multi-layer plasma-resistant coating.

[0022]

[0027] To protect the chamber body 102, an outer liner 116 can be disposed adjacent to the sidewall 108. The outer liner 116 may be a halogen-containing gas-resistant material such as Al2O3 or Y2O3. In some embodiments, the outer liner 116 can be coated with a multi-layer plasma-resistant ceramic coating.

[0023]

[0028] An exhaust port 126 can be defined within the chamber body 102 and connect the internal space 106 to a pump system 128. The pump system 128 can include one or more pumps and throttle valves. These are used to evacuate the internal space 106 of the processing chamber 100 and regulate the pressure of the internal space 106.

[0024]

[0029] The showerhead 130 can be supported on the sidewall 108 of the chamber body 102 and / or on the upper part of the chamber body. The showerhead 130 (or lid) can be opened to allow access to the internal region 106 of the processing chamber 100, and can provide a seal to the processing chamber 100 while closed. The gas panel 158 is connected to the processing chamber 100 to supply a processing gas and / or a cleaning gas to the internal region 106 via the showerhead 130 or lid and nozzles. Examples of processing gases that can be supplied by the gas panel 158 and used to process substrates / samples in the processing chamber 100 include silicon-containing gases, halogen-containing gases such as C2F6, SF6, HBr, NF3, CF4, CHF3, CH2F3, F, NF3, Cl2, CCl4, BCl3, and SiF4, and in particular, other gases such as O2 or N2O. Examples of carrier gases (which can also be referred to as diluents here) include N2, He, Ar, and other gases that are inert to the processing gas (e.g., non-reactive gases). The showerhead 130 includes a plurality of gas supply holes 132 throughout. The showerhead 130 can be or include aluminum, anodized aluminum, an aluminum alloy (e.g., Al6061), or an anodized aluminum alloy. In some embodiments, the showerhead includes a gas supply plate (GDP) joined to the showerhead. The GDP can be, for example, Si or SiC. The GDP can further include a plurality of holes that are aligned with the holes of the showerhead.

[0025]

[0030] The substrate support assembly 148 is disposed within the interior space 106 of the processing chamber 100 below the showerhead 130. The substrate support assembly 148 holds the substrate 144 (e.g., a wafer) during processing. The substrate support assembly 148 may include an electrostatic chuck that fixes the substrate 144 during processing, a metal cooling plate joined to the electrostatic chuck, and / or one or more additional components. An inner liner may cover the periphery of the substrate support assembly 148. The inner liner may be a halogen-containing gas resistive material such as Al2O3 or Y2O3. In some embodiments, the substrate support assembly, a part of the substrate support assembly, and / or the inner liner may be coated with a metal layer and a barrier layer.

[0026]

[0031] The processing chamber 100 may be an etching chamber. In an embodiment, the etching process is performed to selectively etch a film disposed on the surface of the substrate 144. For example, the substrate 144 may be a semiconductor wafer, a glass plate, a SiGe wafer, or another type of substrate. In one embodiment, the film disposed on the substrate 144 includes a polymer film and a self-assembled monolayer. The substrate 144 may further include silicon (Si).

[0027]

[0032] FIG. 2A is a cross-sectional view of an article 200 including a substrate 206. In some embodiments, the article 200 may have a stack of layers (e.g., layers in which two or more materials alternate). The stack of layers may include a stack of silicon (Si) layers, silicon germanium (SiGe) layers, silicon nitride (SiN) layers, silicon dioxide (SiO2) layers, and the like. In an embodiment, the stack includes a stack of layers in which two or more of the foregoing materials alternate (e.g., an alternating stack of Si and SiGe or an alternating stack of Si and SiO2). In one embodiment, the article 200 corresponds to the substrate 144 of FIG. 1. The substrate 206 includes Si layers 260a-f disposed in a stack 290. In some embodiments, the Si layers 260a-f may be in the form of nanosheets (e.g., layers having a thickness on the nm scale). In one embodiment, all of the Si layers 260a-f have substantially the same thickness. Alternatively, the Si layers 260a-f may each have a different thickness.

[0028]

[0033] A pattern mask 280 (also referred to as an etching mask) can cover the uppermost layer 260a of the stack 290. The pattern mask 280 may be a soft mask or a hard mask. Some hard masks that can be used include polycrystalline silicon hard masks and metal hard masks such as tungsten hard masks or titanium nitride hard masks. The pattern mask 280 includes an opening region 270 that exposes the underlying layer to an etching chemical during an etching process. The pattern mask 280 further includes a covered region that protects the underlying layer from the etching chemical. The region of the stack 290 below the opening region 270 not protected by the pattern mask 280 can be the subject of an etching process.

[0029]

[0034] The article 200 is etched through the pattern mask 280, and a cavity or trench substantially the same shape as the opening of the pattern mask 280 can be formed. The etchant typically etches the pattern mask 280 at some etching rate as well.

[0030]

[0035] Figure 2B shows a cross-sectional view of an article 204 including a substrate 206 having a stack of layers 260a - f on which an etching process has been performed. The etching process may be any etching process used in the art, including chemical etching. Chemical etching includes forming ammonium fluoride salts using ammonia and hydrofluoric acid. Other chemical etching includes, but is not limited to, the use of ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride. In the process, cavities 400 (e.g., trenches) are etched within layers 260a - f. In one embodiment, the cavity 400 has a tapered cross-sectional shape with a U-shaped profile where the bottom of the cavity is slightly narrower than the top of the cavity. In particular, the sidewalls of the trenches or holes formed from the etching processes defined in the embodiments herein are substantially vertical, unlike the sidewalls produced by previous etching processes.

[0031]

[0036] In embodiments, a native oxide may be formed at the bottom of the trench. To remove the native oxide, one or more etching or cleaning processes may be performed. However, these etching or cleaning processes may also etch the sidewalls of the trench, which may change the profile of the trench. Additionally or alternatively, after the trench is formed, a further process may be performed to etch the substrate 206 that may be exposed at the bottom of the trench. However, etching the trench bottom (e.g., the substrate 206) may also etch the sidewalls of the trench, again changing the profile of the trench walls. This can have an adverse effect on the critical dimensions of the manufactured device. The embodiments described herein enable cleaning or etching the bottom of the trench without adversely affecting the profile or critical dimensions of the device (e.g., the trench).

[0032]

[0037] In an embodiment, the bottom of the trench is cleaned and / or etched using a process that includes depositing a flowable film on the bottom of the trench without depositing a flowable film on the sidewalls of the trench. The flowable film may be, for example, a liquid flowable chemical vapor deposition (CVD) film. The liquid flowable CVD film can be used to fill or partially fill trenches having an aspect ratio of up to 30:1. In an embodiment, the lack of carbon in the flowable film inhibits transistor insulation and causes voltage shift and voltage leakage. The flowable film can be formed by depositing a liquid precursor that flows to a low point and then reacting the liquid precursor with one or more other materials to form the film.

[0033]

[0038] In other embodiments, the flowable film can be formed by introducing reactants and precursors into the chamber, with the reactants present in the vapor phase in the chamber to form the flowable film. Thus, the flowable film flows into the trench and deposits on the bottom of the trench.

[0034]

[0039] After the formation of the flowable film, a self-assembled monolayer (SAM) is formed. The SAM may not be formed on the flowable film but may be formed on other exposed surfaces. Thus, in an embodiment, the SAM can be formed at any position other than the flowable film at the bottom of the trench. After the SAM is formed, the flowable film can be removed from the bottom of the trench. Thereafter, an etching process can be performed. In this etching process, the selectivity may be higher for the material at the bottom of the trench (e.g., natural oxide such as Si or SiO2) than for the SAM.

[0035]

[0040] FIG. 3 shows a process for forming a self-assembled monolayer (SAM) on the surface 305 of a substrate 310. The substrate 310 can represent, for example, a semiconductor wafer on which one or more trenches (e.g., trenches formed from a stack of alternating materials such as Si and SiO2) are formed. As understood in the art, a SAM is an organic molecule. The molecules are spontaneously formed on the surface by adsorption and, to some degree, are organized as large regular regions. In some embodiments, the molecules forming the SAM do not interact strongly with the substrate. In other embodiments, the molecules have a strong affinity for the substrate and may have a head group that anchors the molecule thereto. https: / / en.wikipedia.org / wiki / Self-assembled_monolayer - cite_note-Love-1. The article 310 and the surface 305 can be made of, for example, Si, SiO2, SiG, SiN, or other materials or combinations of materials.

[0036]

[0041] The individual chemical reactions between the precursor and the surface are known as "half-reactions". Between each of the half-reactions, the precursor is pulsed onto the surface for a sufficient time to allow for a complete reaction with the surface. Since the precursor reacts only with a finite number of available reaction sites on the surface, this reaction is self-limiting and a uniform continuous adsorption layer is formed on the surface. The sites that have already reacted with the precursor cannot react further with the same precursor until and / or unless they are subjected to a process such that the reacted sites form new reaction sites on a uniform continuous coating. Exemplary processes include plasma treatment, treatment exposing the uniform continuous adsorption layer to radicals, or introduction of a different precursor capable of reacting with the latest uniform continuous film layer adsorbed on the surface.

[0037]

[0042] In FIG. 3, a substrate 310 having a surface 305 can be exposed to a first precursor 360 for a first period of time until a first half-reaction of the first precursor 360 with the surface 305 partially forms a layer 315 by forming an adsorption layer 314. In an embodiment, the adsorption layer 314 is not formed on a fluid film that may be deposited on one or more portions of the surface 305 (e.g., the bottom of a trench formed on the surface 305). Thereafter, the article 310 can be exposed to a second precursor 365 (also referred to as a reactant) to cause a second half-reaction, which reacts with the adsorption layer 314 and completely forms the layer 315. The layer 315 can be uniform, continuous, and conformal. To achieve a layer 315 of a target thickness, the substrate 310 may be alternately exposed to the first precursor 360 and the second precursor 365 up to x times. X is, for example, an integer from 1 to 100.

[0038]

[0043] Surface reactions (e.g., half-reactions) are performed sequentially. Before introducing a new precursor, the chamber in which the ALD or MLD process is performed can be purged with an inert carrier gas (e.g., nitrogen or air) to remove any unreacted precursor and / or by-products that have reacted with the surface precursor. In an embodiment, at least two precursors can be used. In some embodiments, two or more precursors can be used to grow multiple film layers having the same composition (e.g., multiple layers of SAMs can be grown to overlap each other). In other embodiments, various precursors can be used to grow various film layers having different compositions.

[0039]

[0044] Depending on the type of ALD or MLD process, the ALD or MLD process can be carried out at various temperatures. The optimal temperature range for a specific ALD or MLD process is referred to as the "ALD temperature window" or the "MLD temperature window". At temperatures lower than the temperature window, the growth rate does not increase, and non-ALD type depositions may occur. Temperatures exceeding the temperature window may cause thermal decomposition of the article or rapid desorption of the precursor. The temperature window can range from about 20°C to about 400°C. In some embodiments, the MLD temperature window is between about 200 and 350°C.

[0040]

[0045] The ALD / MLD process enables a film layer with a uniform thickness of the film on an article, a surface with a complex geometry, pores with a large aspect ratio, and a conformal film layer with a three-dimensional structure. Due to sufficient exposure time of the precursor to the surface, the precursor can be dispersed, enabling a complete reaction with the entire surface including all three-dimensional complex features. The exposure time utilized to obtain conformal ALD in a high aspect ratio structure is proportional to the square of the aspect ratio and can be predicted using modeling techniques. Furthermore, the ALD technique does not require difficult manufacturing of raw materials (e.g., powder raw materials and sintered target materials) over a long period, and enables in-situ on-demand material synthesis of specific compositions or formulations of materials, making it more advantageous than other commonly used coating techniques.

[0041]

[0046] In the ALD / MLD technique, for example, a film such as a self-assembled monolayer (SAM) can be grown by appropriate sequencing of the precursors.

[0042]

[0047] In previous embodiments, chemical passivation or directional etching was used to selectively etch the bottom surface of the trench and not the sidewalls.

[0043]

[0048] FIG. 4 is a flow diagram representing a method 400 for selectively etching or cleaning a substrate according to an embodiment of the present disclosure. In method 400, at block 401, a previously patterned substrate is received. The substrate can be patterned to have at least one trench. The at least one trench can have a top surface, at least one sidewall surface, and a bottom surface. For example, as shown in FIG. 5, the substrate can have a trench. In FIG. 5, at block 501, a substrate 507 having a trench 508 is formed. The substrate 507 can include silicon. The trench 508 has a top surface 511, at least one sidewall 509, and a bottom surface 510. The bottom surface 510 can have an epitaxial silicon (epi) layer 510a formed during or after the formation of the trench 508. In some embodiments, at least one sidewall 509 has a layer 509a different from the epi layer 510a formed on the sidewall 509. In one embodiment, the layer 509a can include silicon nitride (SiN). In other embodiments, the layer 509a can be silicon, damaged silicon nitride, silicon oxide, or a low-k material. As understood herein, the term "low-k material" refers to a material having a lower relative dielectric constant (κ: kappa) than silicon dioxide. In the method 400 of the present disclosure, removal of the epi layer or another layer at the bottom of the trench 508 is enabled without etching the sidewall 509.

[0044]

[0049] Returning to FIG. 4, after receiving the patterned substrate, a polymer film is deposited on the bottom surface of at least one trench of the substrate. This can be confirmed at 502 in FIG. 5. At block 502, a polymer film 512 is deposited on the bottom surface. The polymer film 512 can be deposited by utilizing capillary action. By utilizing capillary action, low vapor pressure and low reactivity are beneficial. Further, in order to utilize capillary action, the chamber must be below the boiling point of the polymer film 512, whereby the polymer film 512 can condense at the bottom of the trench. The polymer film 312 can be deposited to a target height in the trench 308. The target height may be from about 1 nm to about 100 nm, from about 10 nm to about 90 nm, from about 20 nm to about 80 nm, from about 30 nm to about 70 nm, from about 40 nm to about 60 nm, or from about 45 nm to about 55 nm. The polymer film 512 can be deposited by flowing the film onto the bottom surface 510 of the trench.

[0045]

[0050] In an embodiment, the polymer film 512 is formed via a fluid film deposition process such as fluid CVD. In such a process, the liquid precursor may deposit on the substrate and may flow to a low point (e.g., the bottom of the trench) within the substrate.

[0046]

[0051] In some embodiments, the polymer film 512 may comprise a carbon-based compound. The carbon-based compound may include a material selected from Formula A or may be formed from a precursor. TIFF2025521189000002.tif28170 Here, formula A contains two reactive groups "-Y" arranged at the para positions around the central aromatic ring. In one embodiment, the -Y group may include, among other reactive groups, a hydroxyl group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, or an acyl chloride group. In other embodiments, two or more -Y groups, three or more -Y groups, four or more -Y groups, five or more -Y groups, etc. may be arranged around the aromatic ring. Additional embodiments may include each -Y group with the same reactive group, at least two -Y groups with different reactive groups, and all -Y groups with different reactive groups among other combinations of -Y groups in the carbon-based compound and / or precursor. Specific examples of the carbon-based compound or precursor include, among others, hydroquinone, terephthalaldehyde, terephthaloyl chloride, and p-phenylenediamine.

[0047]

[0052] In some embodiments, the polymer film 512 may include, or be formed from, a material selected from Formula 1 and Formula 2, as described in FIG. 3. These materials or precursors may alternatively be pulsed into the chamber using an MLD process. The MLD temperature window may be less than 150°C.

[0048]

[0053] In an embodiment, Formula 1 may be TIFF2025521189000003.tif30170 and here, R may be H, an alkyl group, or an aryl group, and R' may be Cl, Br, I, OR, OH, H, NR2, Si(NCO)4, Si(NCS)4, or TIFF2025521189000004.tif27170 and here, R is H, an alkyl group, or an aryl group, and R' may be Cl, Br, I, OR, OH, H, NR2.

[0049]

[0054] In an embodiment, Formula 2 is TIFF2025521189000005.tif may be 28170, where R, R', and R''' may each independently be H, an alkyl group, or an aryl group, or TIFF2025521189000006.tif may be 29170, where R, R', and R'' may each independently be H, an alkyl group, or an aryl group.

[0050]

[0055] In some embodiments, the polymer film 512 may be terephthalaldehyde. Terephthalaldehyde has been found to be effective on its own without using an amine by adjusting the pulse process (e.g., adjusting the temperature of the pulse process).

[0051]

[0056] In some embodiments, in block 502, the polymer film 512 may be a fluid film that flows onto the bottom surface 510 of the trench 508 during the deposition of the polymer film 512. The deposition of the polymer film 512 can occur at a temperature within a target temperature range. The target temperature range may be from about 0°C to about 400°C, from about 25°C to about 300°C, from about 50°C to about 250°C, or from about 75°C to about 200°C, or from about 200°C to about 400°C, from about 100°C to about 300°C, or any value or sub-range not disclosed herein. The polymer film 512 flows onto the bottom surface 510 of the trench 508 without adhering to the sidewalls 509.

[0052]

[0057] During the deposition of the polymer film 512, a purge gas may also be supplied. The purge gas may be any inert gas such as nitrogen, argon, or helium. In embodiments, the deposition of the polymer film can be performed using a molecular layer deposition (MLD) or chemical vapor deposition (CVD) process.

[0053]

[0058] Returning to FIG. 4, after the polymer film is deposited on the bottom of the trench, a second film is selectively formed on the layer of the substrate. The second film can be a blocking film. In block 403, the second film is selectively formed on the layer of the substrate without forming the second film on the polymer film. That is, the second film may be formed on the top surface of at least one trench, at least one side wall of at least one trench, or a combination of both. This can be confirmed in block 503 of FIG. 5. As seen in FIG. 5, a second film 513, i.e., a blocking film, is formed on the layer 509a of the substrate. The second film 513 may include a self-assembled monolayer (SAM) that is not formed on the polymer film 512. In an embodiment, the second film 513 is formed using an ALD or MLD process as described with reference to FIG. 3. In other embodiments, the second film 513 may be formed using chemical passivation.

[0054]

[0059] In an embodiment, the second film 513 may include at least one of silylamide, silyl halide, silyl alkoxide, or cyclic silylamide. Silylamide is a compound according to Formula III, silyl halide is a compound according to Formula IV, silyl alkoxide is a compound according to Formula V, and cyclic silylamide is a compound having a C3-C8 ring. R n Si(NR’2) (4-n) Formula III Here, in Formula III, R is each independently a C1-C 18 alkyl group, C1-C 18 alkene group, C1-C 18 alkyne group, C1-C 18 aliphatic group, or C1-C 18 aromatic, and n = 1 to 3. R n SiX (4-n) Formula IV Here, in Formula IV, R is each independently a C1-C 18 alkyl group, C1-C 18 alkene group, C1-C 18 alkyne group, C1-C 18 aliphatic group, C1-C18 is aromatic, X is Cl, F, Br, or I, and n = 1 to 3, R n Si(OR’) (4-n) Formula V wherein, in Formula V, each R is independently a C1-C 18 alkyl group, a C1-C 18 alkene group, a C1-C 18 alkyne group, a C1-C 18 aliphatic group, or a C1-C 18 is aromatic, and n = 1 to 3.

[0055]

[0060] In some embodiments, the silylamide can be used for surface SiO functionalization. In other embodiments, when SiN functionalization can be used, an aldehyde may be used as the second film. In yet other embodiments, silylchlorides can be used for both SiN and SiO functionalization.

[0056]

[0061] The second film 513 can be selectively formed on the surface of the trench 508 without forming on the polymer film at the bottom of the trench. As shown in block 503, the second film 513 can be selectively formed on the upper surface 511 and the sidewall 509 of the trench 508 without forming on the polymer film 512. Alternatively, the second film 513 may be selectively formed only on the sidewall 509 of the trench 508.

[0057]

[0062] In an alternative embodiment, since there is a selectivity window for the second film material, the formation of the second film 513 can be repeated so that the sidewall surface is surely completely or almost completely covered with the SAM. That is, depending on the chemical substance used, a gap may occur when applying the second film 513 or the SAM to the sidewall, so the cycle may be performed multiple times. Therefore, the second film 513 or the SAM has selectivity such that it is formed only on the sidewall.

[0058]

[0063] Returning to the flowchart of FIG. 4, after the second film is formed on the substrate, in block 404, the polymer film is removed from the bottom of the trench. This is shown in block 504 of FIG. 5 and will be described herein. As seen in FIG. 5, after the second film is formed, the polymer film 512 is removed from the bottom 510 of the trench. In an embodiment, the polymer film can be removed by heating the substrate. The substrate can be heated within the boiling point range of the polymer film 512. The boiling point range may be from about 200 °C to about 400 °C, or from about 250 ° to about 350 °C. The substrate can be heated for about 5 minutes to about 30 minutes, about 10 minutes to about 25 minutes, or about 15 minutes to about 20 minutes. As a result of heating the substrate, the polymer film may transition to a gas, and this gas may be pumped out of the chamber in which the substrate is being processed.

[0059]

[0064] In some embodiments, the polymer film can be removed using plasma. For example, the substrate can be exposed to a plasma containing H2, NF3, Ar, He, N2, O2, and / or mixtures thereof. The plasma can react with the polymer film to form a gas. This gas can be pumped out of the chamber containing the substrate.

[0060]

[0065] As shown in FIG. 4, after the polymer film is removed in block 404, in block 405, an etching process is performed on the substrate. This is shown in block 505 of FIG. 5. The bottom surface 510 of the trench 508 can be etched using an etching chemical. While etching the bottom surface 510 of the trench 508, the second film 513 protects the sidewalls from the etching chemical (i.e., selectively etches the substrate). During the etching process, epi oxide (e.g., epitaxial silicon dioxide) can be removed from the bottom surface. In some embodiments, the chemical etching process can be performed using ammonia and / or hydrofluoric acid. Other chemicals include, but are not limited to, ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride. In an embodiment, the etching process is a plasma etching process. In an embodiment, the etching process is a wet etching process. Further, the etching process may be an isotropic etching or an anisotropic etching.

[0061]

[0066] As shown in FIG. 4, after the etching process is performed, in block 406, the second film is removed from the substrate. This can also be confirmed in block 506 of FIG. 5. Here, the second film 513 is removed from the sidewalls of the trench. The second film 513 can be removed by an additional chemical etching process using one of the chemicals described above. Thus, after passing through the selective etching process, the trench 508 of the substrate has no epi layer, and since it is protected by the SAM during the etching process, the profile of the trench is maintained.

[0062]

[0067] The chemical etching process can be performed using ammonia and hydrofluoric acid, or ammonium fluoride. Other chemicals include, but are not limited to, ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride.

[0063]

[0068] In one embodiment, the etching process can be performed using ammonium fluoride. When the SAM is formed on the sidewalls, the ammonium fluoride is prevented from interacting with the sidewalls by the carbon-based groups. Thus, these carbon-based groups act as blocking agents during the trench chemical etching process.

[0064]

[0069] The foregoing description has set forth numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of several embodiments of the present invention. However, it will be apparent to those skilled in the art that at least some embodiments of the present invention can be practiced without these specific details. In other instances, well-known components or methods have not been described in detail or are presented in a simple block diagram format to avoid unnecessarily obscuring the present invention. Thus, the specific details shown are merely illustrative. Specific implementations may vary from these illustrative details and still be considered within the scope of the present invention.

[0065]

[0070] Throughout this specification, references to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". When the terms "about" or "approximately" are used in this specification, it is intended to mean that the recited nominal value is accurate within ±10%.

[0066]

[0071] The steps of the methods described herein are illustrated and described in a particular order, but the order of each method step may be changed so that a particular step can be performed in the reverse order or so that a particular step can be performed at least partially concurrently with other steps. In another embodiment, the instructions or sub-steps of separate steps can be performed intermittently and / or alternately.

[0067]

[0072] It should be understood that the foregoing description is intended to be illustrative and not limiting. Many other embodiments will be apparent to those skilled in the art upon reading and understanding the above description. Therefore, the scope of the present invention shall be determined with reference to the appended claims along with the full scope of equivalents to which such claims are entitled.

Claims

1. placing a substrate in a chamber, wherein the substrate includes a layer in which at least one trench is formed, and the at least one trench has a top surface, a bottom surface, and at least one sidewall; depositing the polymer film on the bottom surface of the at least one trench without depositing the polymer film on the at least one sidewall of the at least one trench; selectively forming a second film on the layer without forming the second film on the polymer film; removing the polymer film from the bottom surface of the at least one trench; etching the bottom surface of the trench using an etching chemical, wherein the second film protects the at least one sidewall from the etching chemical; A method comprising the above steps.

2. The method according to claim 1, wherein the second film includes a self-assembled monolayer (SAM) that is not formed on the polymer film.

3. The method according to claim 1, wherein the layer includes silicon, silicon nitride, damaged silicon nitride, silicon oxide, or a low-k material, and the substrate includes silicon.

4. The method according to claim 1, wherein the bottom surface has a U-shaped profile and the substrate includes the bottom surface.

5. The method according to claim 1, further comprising removing the second film after performing the etching.

6. The method according to claim 1, wherein removing the polymer film includes at least one of heating the polymer film or exposing the polymer film to plasma.

7. The method according to claim 1, wherein the polymer film includes a carbon-based compound.

8. The carbon-based compound includes at least one precursor selected from the combination of Formula 1 and Formula A and Formula B, Formula 1 is (Here, R may be H, an alkyl group, or an aryl group, and R' may be Cl, Br, I, OR, OH, H, NR ２ , Si(NCO) ４ , or Si(NCS) ４ (and may be)), and (Here, R may be H, an alkyl group, or an aryl group, and R' may be Cl, Br, I, OR, OH, H, NR ２ .) One of the following, Formula 2 is wherein R, R', and R'' may each independently be H, an alkyl group, or an aryl group, and wherein R, R', and R'' may each independently be H, an alkyl group, or an aryl group One of the following. The method according to claim 7.

9. The carbon-based compound is Formula A The method according to claim 7, comprising a precursor selected from, wherein Y is a hydroxyl group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, or an acyl chloride group, and formula A contains two reactive groups.

10. The method according to claim 7, wherein the carbon-based compound is terephthalaldehyde.

11. The method according to claim 1, wherein the second film comprises at least one of a silylamide, a silyl halide, a silyl alkoxide, and a cyclic silylamide.

12. The silylamide is a compound according to formula III, the silyl halide is a compound according to formula IV, the silyl alkoxide is a compound according to formula V, and the cyclic silylamide is C ３ -C ８ a compound having a ring, Here, Formula IV is R ｎ Si(NR'2) （４－ｎ） In Formula IV, each R is independently C １ -C １８ an alkyl group, C １ -C １８ an alkene group, C １ -C １８ an alkyne group, C １ -C １８ an aliphatic group, or C １ -C １８ is aromatic, and n = 1 to 3 Formula V is R ｎ SiX （４－ｎ） In formula V, each R is independently C １ -C １８ an alkyl group, C １ -C １８ an alkene group, C １ -C １８ an alkyne group, C １ -C １８ an aliphatic group, C １ -C １８ is aromatic, X is Cl, Br, or I, and n = 1 to 3 Formula VI is R ｎ Si(OR') （４－ｎ） In formula VI, each R is independently C １ -C １８ alkyl group, C １ -C １８ alkene group, C １ -C １８ alkyne group, C １ -C １８ aliphatic group, or C １ -C １８ aromatic, and n = 1 to 3, the method according to claim 11.

13. The method according to claim 1, wherein the polymer film is a fluid film that flows on the bottom surface of the at least one trench while depositing a fluid film at a temperature within a target temperature range.

14. The method according to claim 1, wherein as a result of being protected from the etching chemical by the second film, the at least one sidewall of the at least one trench is not etched.

15. The method according to claim 1, further comprising removing oxide from the bottom surface of the at least one trench during the etching.

16. The method according to claim 1, wherein the etching chemical comprises ammonium fluoride.

17. Placing a substrate in a chamber, the substrate comprising a layer in which at least one trench is formed, the at least one trench having a top surface, a bottom surface, and at least one sidewall, and placing the substrate; Depositing the polymer film on the bottom surface of the at least one trench without depositing the polymer film on the at least one sidewall of the at least one trench; Selectively forming the second film on the layer without forming the second film on the polymer film A method comprising.

18. The method according to claim 17, wherein the polymer film is a fluid film that flows on the bottom surface of at least one trench while depositing a fluid film at a temperature within a target temperature range.

19. The method according to claim 17, wherein the polymer film is terephthalaldehyde and the second film comprises a self-assembled monolayer (SAM) that is not formed on the polymer film.

20. Placing a substrate in a chamber, wherein the substrate includes a layer in which at least one trench is formed, and the at least one trench has a top surface, a bottom surface, and at least one side wall. Depositing a polymer film on the bottom surface of the at least one trench without depositing the polymer film on the at least one side wall of the at least one trench. Selectively forming a second film on the layer without forming the second film on the polymer film. Removing the polymer film from the bottom surface of the at least one trench. Performing an etching process including applying ammonium fluoride to the substrate. Including, wherein performing the etching process selectively interacts with the bottom surface of the at least one trench and does not interact with the top surface and the at least one side wall.

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