Selective etch of substrates

Abstract

A method for selectively cleaning and / or etching a sample is described herein. The method includes selectively forming a film in a trench of a substrate such that the trench may be selectively etched. A polymer film is deposited on the bottom surface of the trench and not on the sidewalls. A second film is selectively formed in the trench without forming the second film on the polymer film. The polymer is then removed from the bottom surface of the trench, and then an etch is performed on the bottom surface of the trench using an etch chemistry, where the second film protects the sidewalls from being etched.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to a method for etching a substrate, wherein the method for etching uses a flowable polymer film to achieve improved etch selectivity between different regions of the substrate. Background Art

[0002] In the semiconductor industry, devices are manufactured through many manufacturing processes that produce structures with ever-shrinking dimensions. As device geometries shrink, controlling process uniformity and reproducibility across devices becomes more challenging, especially in upstream processing.

[0003] Integrated circuits are realized by a variety of processes that produce intricately patterned layers of material on a substrate surface. The production of patterned materials on a substrate uses controlled methods of forming and removing exposed materials. For example, in a gap fill operation, material can be formed or deposited to fill a trench or other feature formed on a semiconductor substrate. Since the trench or feature can be characterized by a high aspect ratio and a reduced critical dimension, these filling operations can be challenging. For example, since deposition may occur at the top of the trench or feature and along the sidewalls of the trench or feature, continuous deposition may pinch off the trench or feature (including between the sidewalls within the trench) and may produce gaps. This may then affect device performance and subsequent processing operations.

[0004] In current etching processes, substrates can be made of silicon and silicon nitride. When the substrate is exposed to air, the substrate may have a bottom including silicon oxide (SiO) and a sidewall of silicon oxynitride (SiON). As the device continues to shrink, the target etching parameters are also reduced. In order to solve this problem, selective etching or selective chemical passivation is preferred. Since the bottom and the sidewall contain similar materials (SiO and SiON), selective etching or selective chemical passivation is difficult to apply. 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] In some embodiments of the present disclosure, a method for cleaning and etching a sample is provided. The method may include placing a substrate into a chamber, wherein the substrate may include a layer, the layer including at least one groove formed in the layer. At least one groove of the method may have 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 groove without depositing the polymer film on at least one sidewall of at least one groove. In some embodiments, the method may include selectively forming a second film on the layer without forming a 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 groove. In some embodiments, the method may further include etching the bottom surface of the groove using an etching chemistry, wherein the second film protects at least one sidewall from being affected by the etching chemistry.

[0006] In another embodiment of the present disclosure, a method for cleaning and etching a substrate is provided. The method may include placing a substrate into a chamber, wherein the substrate includes a layer having at least one groove formed in the layer, the at least one groove having a top surface, a bottom surface, and at least one sidewall. The method further includes depositing a polymer film on the bottom surface of at least one groove without depositing the polymer film on at least one sidewall of the at least one groove, 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 at least one groove, performing an etching process, wherein the etching process includes applying ammonium fluoride to the substrate. The etching process of the method may selectively interact with the bottom surface of the at least one groove, and does not interact with the top surface and at least one sidewall. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, wherein like reference numerals refer to like elements. It should be noted that different references to "one" or "an" embodiment in the present disclosure do not necessarily refer to the same embodiment, and such references mean at least one.

[0008] Figure 1 A cross-sectional view of a processing chamber is depicted in accordance with one embodiment.

[0009] Figure 2A depicts a cross-sectional view of multiple layers of a sample of one embodiment;

[0010] Figure 2B depicts a cross-sectional view of multiple layers of a sample of one embodiment, wherein the sample has been etched to have a U-shaped profile;

[0011] Figure 3Describing deposition processes according to various molecular layer deposition techniques;

[0012] Figure 4 is a flow chart representing a method for selectively cleaning a substrate according to an embodiment of the present disclosure; and

[0013] Figure 5 A trench of a substrate being selectively cleaned according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0014] Polymer films can be used in the manufacture of semiconductor device elements of various structures and processes, including applications as mask materials, etch-resistant materials, and trench filling materials. More specific application examples of polymer films include the formation of thermal implant hard masks, metal gate (MG) cutting hard masks, MG manufacturing, and reverse tone patterning. The present disclosure includes forming a polymer film on a semiconductor substrate using molecular layer deposition (MLD).

[0015] Embodiments disclosed herein describe a method for selectively cleaning and / or selectively etching a substrate. The method for cleaning / etching a substrate may include placing a substrate into a chamber, wherein the substrate may include a layer, the layer including at least one groove formed in the layer, the at least one groove having 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 groove without depositing a polymer film on at least one sidewall of at least one groove. The method may further include selectively forming a barrier film on the layer without forming a barrier film on the polymer film. For example, a barrier film may be formed using a self-assembled monolayer (SAM) deposition technique. The method may further include removing the polymer film from the bottom surface of at least one groove and etching the bottom surface of the groove using an etching chemistry, wherein the barrier film protects at least one sidewall from being affected by the etching chemistry.

[0016] By selectively coating one or more portions of a substrate with different films, the profile of the substrate can be improved and the blowout of the critical dimensions of the grooves can be improved. It has been found that the use of a self-assembled monolayer (SAM) blocks and / or protects the surface from being etched. By selectively protecting the surface from being etched, this allows the removal of material in selective areas of the groove (e.g., such as any oxidized surface) while avoiding the blowout of critical dimensions (e.g., such as the groove width or profile). The inventors have found that the bottom surface of the groove in the substrate is often oxidized, which is often detrimental to the performance of the final product. In order to remove the oxidized surface, an etching process step can be performed. However, at this stage, not every surface needs to be etched, as this may affect the profile of the substrate (e.g., the profile of the groove formed in or on the substrate).

[0017] Therefore, SAM can be formed on the top surface, side surface or the combination of the above-mentioned surfaces to protect these surfaces from being etched. The inventor has found that depositing a polymer film on the bottom surface of the groove prevents SAM from being formed on the bottom surface, so that SAM is formed on the top surface, side wall surface or the combination of the above-mentioned surfaces. In a plurality of embodiments, SAM is composed of an ordered arrangement of spontaneously assembled organic molecules adsorbed on the surface. These molecules generally include one or more parts (head groups) with affinity to the substrate and relatively long, inert, linear parts.

[0018] In a plurality of embodiments, flowable polymer is deposited on substrate, wherein flowable polymer will not be attached to the sidewall of groove, but gathers in the bottom of groove.Flowable polymer can solidify (set) or harden at the bottom of groove surface, and can not be formed on the sidewall of groove. Subsequently, SAM can not be attached to the polymer selectively deposited on the bottom of groove. Therefore, after selectively forming SAM (for example, all places except the polymer at the bottom of groove), the polymer film at the bottom of groove can be removed. Afterwards, etching chemistry can selectively etch the oxide on the bottom surface of groove and / or etch the bottom surface of groove with the rate much higher than this etching chemistry SAM. Therefore, the sidewall and / or the top of SAM protection groove are not etched, and etching can be selectively performed on the bottom surface of groove.

[0019] By selectively etching or cleaning certain surfaces of the trenches of the substrate without etching other surfaces of the trenches, it is found that in the etched sample (i.e., substrate), the trench width has a lower degree of variation across the trench depth than in conventional plasma etching processes. Thus, the inventors have discovered a method for selectively cleaning or etching the bottom surface of the trench without etching or barely etching the top and / or sidewalls of the trench.

[0020] In various embodiments, because 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, according to various aspects of the present disclosure, the SAM can react with a surface that does not have a polymer film thereon.

[0021] Disclosed herein is an embodiment of a method for selectively cleaning or etching a substrate, the method comprising depositing a polymer film and selectively forming a second film on the substrate. Then, the polymer film is removed and the substrate is etched until a target amount of the substrate is etched. The polymer film can be deposited on the bottom surface of at least one groove of the substrate so that when the second film is formed on the substrate, the second film will not be formed on the bottom surface due to 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 depositing and / or forming the film thereon.

[0022] As used herein, the term "substrate" refers to a surface or a portion of a surface on which processing is performed. Those skilled in the art will also understand that references to a substrate may also refer to only a portion of a substrate, unless the context clearly indicates otherwise. In addition, references to "deposited on a substrate" may refer to a bare substrate and a substrate on which one or more films or features are deposited or formed.

[0023] As used herein, a substrate may also refer to any substrate on which film processing is performed during a manufacturing process or a material surface formed on a substrate. For example, depending on the application, substrate surfaces on which processing can be performed include materials such as 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. Substrates include, but are not limited to, semiconductor wafers.

[0024] The substrate may be exposed to pretreatment treatments to grind, etch, reduce, oxidize, hydroxylate (or otherwise generate or graft a target chemical moiety to impart chemical functionality), anneal, and / or bake the substrate surface. In addition to performing film treatments directly on the surface of the substrate itself, in the present disclosure, any film treatment steps disclosed may also be performed on an underlayer formed on the substrate, as disclosed in more detail below, and the term "substrate surface" is intended to include such underlayers as referred to in the context. Thus, for example, when a film / layer or portion of a film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface. What is included on a given substrate surface depends on what film is to be deposited and the specific chemistry used. In one or more embodiments, the first substrate surface may include a metal, metal oxide, or H-terminated Si x Ge1-x , and the second substrate surface may include a Si-containing dielectric, or vice versa. In some embodiments, the substrate surface may include certain functionalities (eg, -OH, -NH, etc.).

[0025] Now referring to the accompanying drawings, Figure 1 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 for processes in which a corrosive plasma environment and / or a corrosive chemistry is provided. 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 the plasma in the processing chamber 100 are a substrate support assembly 148, an electrostatic chuck (ESC), an annulus (e.g., a process kit ring or a single annulus), a chamber wall, a pedestal, a showerhead 130, a gas distribution plate, a liner, a liner kit, a shield, a plasma baffle, a flow homogenizer, a cooling pedestal, a chamber window, a chamber cover, a nozzle, a process kit ring, etc. In various embodiments, the processing chamber 100 is used to perform an etching process on a patterned substrate, the patterned substrate comprising a plurality of grooves formed on the substrate.

[0026] In one embodiment, the processing chamber 100 includes a chamber body 102 and a showerhead 130 surrounding an interior space 106. 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 bonded to the showerhead base. Alternatively, in some embodiments, the showerhead 130 may be replaced by a cover and a nozzle, or in other embodiments by a plurality of pie-shaped showerhead compartments and a plasma generation unit. The chamber body 102 may be made of aluminum, stainless steel, or other suitable materials. The chamber body 102 generally includes a sidewall 108 and a bottom 110. Any of the showerhead 130 (or cover and / or nozzle), the sidewall 108, and / or the bottom 110 may include a multi-layer plasma-resistant coating.

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

[0028] An exhaust port 126 may be defined in the chamber body 102 and may couple the interior space 106 to a pump system 128. The pump system 128 may include one or more pumps and throttle valves for evacuating and regulating the pressure of the interior space 106 of the processing chamber 100.

[0029] The showerhead 130 may be supported on the sidewall 108 of the chamber body 102 and / or on the top portion of the chamber body. The showerhead 130 (or lid) may be opened to allow access to the interior space 106 of the processing chamber 100 and may provide a seal for the processing chamber 100 when closed. A gas control panel 158 may be coupled to the processing chamber 100 to provide processing gases and / or carrier gases to the interior space 106 through the showerhead 130 or lid and nozzles. Examples of processing gases that may be delivered by the gas control 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 other gases such as O2 or N2O. Examples of carrier gases (also referred to herein as diluents) include N2, He, Ar, and other gases that are inert to the process gas (e.g., non-reactive gases). The showerhead 130 includes a plurality of gas delivery holes 132 throughout the showerhead 130. The showerhead 130 may be or may include aluminum, anodized aluminum, an aluminum alloy (e.g., Al 6061), or an anodized aluminum alloy. In some embodiments, the showerhead includes a gas distribution plate (GDP) bonded to the showerhead. The GDP may be, for example, Si or SiC. The GDP may additionally include a plurality of holes aligned with the holes in the showerhead.

[0030] The substrate support assembly 148 is disposed in 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 to fix the substrate 144 during processing, a metal cooling plate bonded 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 resistant material, such as Al2O3 or Y2O3. In some embodiments, the substrate support assembly, portions of the substrate support assembly, and / or the inner liner may be coated with a metal layer and a barrier layer.

[0031] The processing chamber 100 may be an etching chamber. In various embodiments, an etching process is performed to selectively etch a film disposed on a 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).

[0032] Figure 2AA cross-sectional view of an article 200 including a substrate 206 is shown. In some embodiments, the article 200 may have a layer stack (e.g., alternating layers of two or more materials). The layer stack may include a stack of silicon (Si) layers, silicon germanium (SiGe) layers, silicon nitride (SiN) layers, silicon dioxide (SiO2) layers, etc. In various embodiments, the stack includes a stack of alternating layers of two or more of the above materials (e.g., alternating stacks of Si and SiGe, alternating stacks of Si and SiO2, etc.). In one embodiment, the article 200 corresponds to Figure 1 The substrate 144 is a substrate 206. The substrate 206 includes Si layers 260a-260f disposed on the substrate in the form of a stack 290. In some embodiments, the Si layers 260a-260f may be in the form of nanosheets (e.g., layers having nanoscale thickness). In one embodiment, all Si layers 260a-260f have approximately the same thickness. Alternatively, different Si layers 260a-260f may have different thicknesses.

[0033] The pattern mask 280 (also referred to as an etching mask) can cover the top layer 260a in the stack 290. The pattern mask 280 can be a soft mask or a hard mask. Some hard masks that can be used include polysilicon hard masks and metal hard masks, such as tungsten hard masks or titanium nitride hard masks. The pattern mask 280 includes opening areas 270 that expose the layers below to etching chemicals during the etching process. The pattern mask 280 additionally includes a cover area that protects the layers below from the etching chemicals. Areas of the stack 290 that are not protected by the pattern mask 280 and are located below the opening areas 270 can undergo etching.

[0034] The article 200 can be etched through the pattern mask 280 to create cavities or trenches having substantially the same shape as the openings in the pattern mask 280. The etchant also typically etches the pattern mask 280 at a certain etching rate.

[0035] Figure 2BA cross-sectional view of an article 204 is shown including a substrate 206 having a layer stack 260a to 260f that has undergone an etching process. The etching process can be any etching process used in the art, including chemical etching. Chemical etching can include the use of ammonia and hydrofluoric acid to form an ammonium fluoride salt. Other chemical etchings can include, but are not limited to, the use of ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride. The process has etched a cavity 400 (e.g., a groove) in the layers 260a to 260f. In one embodiment, the cavity 400 has a tapered cross-sectional shape, wherein the bottom of the cavity is slightly narrower than the top of the cavity, having a U-shaped profile. It is noteworthy that, in contrast to the sidewalls produced by the prior art etching process, the sidewalls of the grooves or holes formed by the etching process proposed in the embodiments of the present invention are almost vertical.

[0036] In a number of embodiments, a native oxide may be formed on the bottom of the trench. In order 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, further processing may be performed to etch the substrate 206 that may be exposed at the bottom of the trench. However, etching the bottom of the trench (e.g., substrate 206) may also cause etching of the sidewalls of the trench, thereby changing the profile of the trench wall again. This may affect the critical dimensions of the manufactured device. The embodiments described herein enable the bottom of the trench to be cleaned or etched without negatively affecting the profile or critical dimensions of the device (e.g., trench).

[0037] In various embodiments, 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 the flowable film on the sidewalls of the trench. The flowable film can 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 with aspect ratios as high as 30:1. In various embodiments, the flowable film lacks carbon in the film, which hinders transistor isolation and causes voltage offsets and 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 a film.

[0038] In other embodiments, the flowable film can be formed by introducing reactants and precursors into the chamber so that the reactants are present in the chamber in a gas phase and form the flowable film. Thus, the flowable film flows into the trench and is deposited at the bottom of the trench.

[0039] After forming the flowable film, a self-assembled monolayer (SAM) is formed. SAM may not be formed on the flowable film, but may be formed on other exposed surfaces. Therefore, in a plurality of embodiments, SAM may be formed anywhere except the flowable film at the bottom of the groove. After forming SAM, the flowable film may be removed from the bottom of the groove. Then etching may be performed, wherein etching may have high selectivity compared to SAM to the material at the bottom of the groove (e.g., Si or native oxide such as SiO2).

[0040] Figure 3 The process for forming a self-assembled monolayer (SAM) on the surface 305 of a substrate 310 is described. The substrate 310 can represent, for example, a semiconductor wafer, on which one or more grooves (e.g., grooves formed by stacking of alternating materials, such as Si and SiO2) are formed. As understood in the art, a SAM can be an organic molecule, wherein the molecule is spontaneously formed on the surface by adsorption, and is organized into more or less large-scale ordered domains. In some embodiments, the molecules forming the SAM do not interact strongly with the substrate. In other embodiments, the molecule can have a head group, which has a strong affinity to the substrate and anchors the molecule to the substrate. https: / / en.wikipedia.org / wiki / Self-assembled_monolayer-cite_note-Love-1 Article 310 and surface 305 may be made of, for example, Si, SiO2, SiG, SiN, or any other material or combination of materials.

[0041] Each individual chemical reaction between a precursor and a surface is referred to as a "half-reaction". During each half-reaction, the precursor is pulsed onto the surface for a duration sufficient to allow the precursor to fully react with the surface. The reaction is self-limiting in that the precursor will only react with a limited number of available reactive sites on the surface, thereby forming a uniform, continuous adsorbed layer on the surface. Any site that has reacted with a precursor becomes unavailable for further reaction with the same precursor unless and / or until the reacted site is treated to form new reactive sites on the uniform, continuous coating. Exemplary treatments may be plasma treatments, treatments by exposing the uniform, continuous adsorbed layer to free radicals, or the introduction of a different precursor that is capable of reacting with the latest uniform, continuous film layer adsorbed to the surface.

[0042] exist Figure 3, a substrate 310 having a surface 305 can be exposed to a first precursor 360 for a first duration until a first half reaction of the first precursor 360 with the surface 305 partially forms a layer 315 by forming an adsorbed layer 314. In various embodiments, the adsorbed layer 314 is not formed on a flowable film, which may have been deposited on one or more portions of the surface 305 (e.g., the bottom of a groove formed on the surface 305). Subsequently, the article 310 can be exposed to a second precursor 365 (also referred to as a reactant) to cause a second half reaction to react with the adsorbed layer 314 and completely form the layer 315. The layer 315 can be uniform, continuous, and conformal. The substrate 310 can be exposed to the first precursor 360 and the second precursor 365 alternately for x times to achieve a target thickness of the layer 315. For example, x can be an integer from 1 to 100.

[0043] Surface reactions (e.g., half reactions) are performed sequentially. Before introducing new precursors, the chamber in which the ALD or MLD process occurs can be purged with an inert carrier gas (e.g., nitrogen or air) to remove any unreacted precursors and / or surface precursor reaction byproducts. At least two precursors can be used in various embodiments. In some embodiments, more than two precursors can be used to grow film layers having the same composition (e.g., to grow multilayer SAMs on top of each other). In other embodiments, different precursors can be used to grow different film layers having different compositions.

[0044] The ALD or MLD process can be performed at various temperatures depending on the type of ALD or MLD process. The optimal temperature range for a particular ALD or MLD process is referred to as the "ALD temperature window" or "MLD temperature window". Temperatures below the temperature window may result in poor growth rates and non-ALD type deposition. Temperatures above the temperature window may result in thermal decomposition of the article or rapid desorption of the precursor. The temperature window may be in the range of about 20°C to about 400°C. In some embodiments, the MLD temperature window is between about 200-350°C.

[0045] ALD / MLD processing allows the formation of conformal films with uniform film thickness on articles and surfaces with complex geometries, holes with large aspect ratios, and three-dimensional structures. Sufficient exposure time of the precursor to the surface allows the precursor to disperse and fully react with the entire surface, including all three-dimensional complex features of the surface. The exposure time required to obtain conformal ALD in high aspect ratio structures is proportional to the square of the aspect ratio and can be predicted using modeling techniques. In addition, ALD technology is more advantageous than other commonly used coating technologies because ALD technology allows for the in-situ synthesis of materials of specific compositions or recipes on demand without the need for lengthy and difficult source material manufacturing (such as powder feedstocks and sintered targets).

[0046] Using ALD / MLD techniques, films such as self-assembled monolayers (SAMs) can be grown by appropriate sequencing of the precursors.

[0047] In previous embodiments, chemical passivation or directional etching is used to selectively etch the bottom surface of the trench without etching the sidewalls.

[0048] Figure 4 4 is a flow chart showing a method 400 for selectively etching or cleaning a substrate according to an embodiment of the present disclosure. In the method 400, at block 401, a substrate that has been patterned 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, the substrate can have Figure 5 The groove shown. Figure 5 In the embodiment of the present invention, a substrate 507 having a trench 508 is formed in frame 501. The substrate 507 may include silicon. The trench 508 has a top surface 511, at least one sidewall 509, and a bottom surface 510. The bottom surface 510 may have an epitaxial silicon oxide (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 formed on the sidewall 509 that is different from the epitaxial layer 510a. In one embodiment, the layer 509a may include silicon nitride (SiN). In other embodiments, the layer 509a may be silicon, damaged silicon nitride, silicon oxide, or a low-κ material. As understood herein, the term "low-κ material" refers to a material having a small relative dielectric constant (κ, kappa) relative to silicon dioxide. The method 400 of the present disclosure allows the epitaxial layer or another layer at the bottom of the trench 508 to be removed without etching the sidewall 509.

[0049] Return to reference Figure 4 After receiving the patterned substrate, a polymer film is deposited onto the bottom surface of at least one trench of the substrate. This can be Figure 5 502 of . In frame 502, polymer film 512 is deposited on the bottom surface. Capillary action can be used to deposit polymer film 512. By utilizing capillary action, low vapor pressure and low reactivity are advantageous. In addition, in order to use capillary action, the chamber should be lower than the boiling point of polymer film 512 so that polymer film 512 can condense at the bottom of the groove. Polymer film 312 can be deposited to the target height of groove 308. The target height can be about 1nm to about 100nm, about 10nm to about 90nm, about 20nm to about 80nm, about 30nm to about 70nm, about 40 to about 60nm, or about 45nm to about 55nm. Polymer film 512 can be deposited by flowing the film to the bottom surface 510 of the groove.

[0050] In various embodiments, the polymer film 512 is formed by a flowable film deposition process such as flowable CVD. In such a process, a liquid precursor may be deposited on the substrate, which may flow to a low point in the substrate (eg, the bottom of a trench).

[0051] In some embodiments, the polymer film 512 may include a carbon-based compound. The carbon-based compound may include a material or may be formed from a precursor, which is selected from Formula A.

[0052]

[0053] Wherein, general formula A includes two reactive groups "-Y" arranged in para position around the central aromatic ring. In one embodiment, the -Y group may include reactive groups such as hydroxyl, aldehyde, ketone, acid, amino, isocyanate, thiocyanate or acyl chloride. In other embodiments, there may be two or more -Y groups, three or more -Y groups, four or more -Y groups, five or more -Y groups, etc. arranged around the aromatic ring. Additional embodiments may also include: in the carbon-based compound and / or precursor, each -Y group is the same reactive group, at least two -Y groups are different reactive groups, and all -Y groups are different reactive groups, as well as other combinations of -Y groups. Specific examples of carbon-based compounds or precursors include hydroquinone, terephthalaldehyde, terephthaloyl chloride and p-phenylenediamine, etc.

[0054] In some embodiments, the polymer film 512 may include a material or may be formed from a precursor selected from Formula 1 and Formula 2, which may be used as Figure 3 The MLD process described in is delivered to the chamber in an alternate pulsed manner. The MLD temperature window can be below 150°C.

[0055] In various embodiments, Formula 1 may be:

[0056]

[0057] Wherein R can be H, alkyl or aryl and R' can be Cl, Br, IOR, OH, H NR2, Si(NCO)4, Si(NCS)4, or

[0058]

[0059] Wherein R can be H, alkyl or aryl, and R' can be Cl, Br, IOR, OH, HNR2.

[0060] In various embodiments, Formula 2 can be

[0061]

[0062] wherein R, R' and R" may each independently be H, alkyl or aryl; or

[0063]

[0064] Wherein, R, R' and R" can each independently be H, an alkyl group or an aryl group.

[0065] In some embodiments, the polymer film 512 can be terephthalaldehyde. It has been found that by adjusting the pulse treatment (eg, by adjusting the temperature of the pulse treatment), terephthalaldehyde itself can be effective without the need for an amine.

[0066] In some embodiments, the polymer film 512 can be a flowable film that flows to the bottom surface 510 of the trench 508 during the deposition of the polymer film 512 in frame 502. The deposition of the polymer film 512 can occur at a temperature in a target temperature range. The target temperature range can be about 0°C to about 400°C, about 25°C to about 300°C, about 50°C to about 250°C, or about 75°C to about 200°C, or about 200°C to about 400°C, about 100°C to about 300°C, or any value or sub-range not disclosed herein. The polymer film 512 flows to the bottom surface 510 of the trench 508 without adhering to the sidewalls 509.

[0067] A purge gas may also be applied during the deposition of the polymer film 512. The purge gas may be any inert gas, such as nitrogen, argon, or helium. In various embodiments, the deposition of the polymer film may be performed using a molecular layer deposition (MLD) or chemical vapor deposition (CVD) process.

[0068] return Figure 4 After depositing the polymer film on the bottom surface of the groove, a second film is selectively formed on the layer of the substrate. The second film can be a barrier 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 can be formed on the top surface of at least one groove, on at least one sidewall of at least one groove, or a combination of the two. This can be Figure 5 As can be seen in the box 503 of Figure 5 As can be seen, a second film 513, i.e., a barrier film, is formed on 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 various embodiments, the second film 513 is formed using an ALD or MLD process, such as described in reference to Figure 3 In other embodiments, chemical passivation may be used to form the second film 513 .

[0069] In various embodiments, the second film 513 may include at least one of silylamide, silylhalide, silylalkoxide, or cyclic silylamide. Silylamide is a compound according to Formula III, silylhalide is a compound according to Formula IV, silylalkoxide is a compound according to Formula V, and cyclic silylamide is a compound having a C3-C8 ring.

[0070] R n Si(NR'2) (4-n) Formula III

[0071] Wherein, in the general formula III, R is independently C1-C 18 Alkyl, C1-C 18 Alkenyl, C1-C 18 Alkynyl, C1-C 18 Lipid or C1-C 18 Aromatic, with n=1-3;

[0072] R n SiX (4-n) Formula IV

[0073] Wherein, in the general formula IV, R is independently C1-C 18 Alkyl, C1-C 18 Alkenyl, C1-C 18 Alkynyl, C1-C 18 Lipid, C1-C 18 Aromatic,

[0074] X is Cl, F, Br or I, and n = 1-3; and

[0075] R n Si(OR') (4-n) Formula V

[0076] In the general formula V, R is independently C1-C 18 Alkyl, C1-C 18 Alkenyl, C1-C 18 Alkynyl, C1-C 18 Lipid or C1-C 18 Aromatic, and n=1-3.

[0077] In some embodiments, silyl amides can be used for SiO functionalization of the surface. In other embodiments, if SiN functionalization can be used, an aldehyde can be used as the second film. In yet another embodiment, silyl chlorides can be used for both SiN and SiO functionalization.

[0078] The second film 513 may be selectively formed on the surface of the trench 508, but not on the polymer film at the bottom of the trench. As shown in block 503, the second film 513 is selectively formed on the top surface 511 and the sidewall 509 of the trench 508, but not on the polymer film 512. Alternatively, the second film 513 may be selectively formed only on the sidewall 509 of the trench 508.

[0079] In an alternative embodiment, because there is a selective window for the second film material, the second film 513 can be repeatedly formed and ensure that the sidewall surface is completely or almost completely covered by the SAM. That is, depending on the chemicals used, there may be gaps when applying the second film 513 or SAM on the sidewalls, so multiple cycles can be performed. Therefore, the second film 513 or SAM is selective so that it is only formed on the sidewalls.

[0080] Return to reference Figure 4 , after forming the second film on the substrate, the polymer film is then removed from the bottom surface of the trench in block 404. Figure 5 As shown in the block 504 of Figure 5 As can be seen, after forming the second film, the polymer film 512 is removed from the bottom surface 510 of the trench. In various embodiments, 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 can be about 200° C. to about 400° C., or about 250° C. 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 can be converted into a gas that can be pumped out of the chamber in which the substrate is processed.

[0081] 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 that can be pumped out of a chamber containing the substrate.

[0082] If it can be Figure 4 As can be seen, after the polymer film is removed in block 404, an etching process is then performed on the substrate in block 405. Figure 5505 of . The bottom surface 510 of the trench 508 can be etched using an etching chemistry. During etching of the bottom surface 510 of the trench 508, the second film 513 protects the sidewalls from the etching chemistry, i.e., selectively etches the substrate. During the etching process, epitaxial oxide (e.g., epitaxial silicon dioxide) can be removed from the bottom surface. In some embodiments, a chemical etching process can be performed using ammonia and / or hydrofluoric acid. Other chemicals that can be used include, but are not limited to, ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride. In multiple embodiments, the etching process is a plasma etching process. In multiple embodiments, the etching process is a wet etching process. The etching process can also be an isotropic etching or an anisotropic etching.

[0083] If it can be Figure 4 As can be seen, after the etching process is performed, the second film is then removed from the substrate in block 406. This can also be Figure 5 As can be seen in the box 506 of the embodiment, the second film 513 is removed from the trench sidewalls. The second film 513 can be removed by an additional chemical etching process using one of the above-mentioned chemicals. Therefore, after undergoing the selective etching process, the trench 508 of the substrate does not have an epitaxial layer and the profile of the trench is maintained because the trench is protected by the SAM during the etching process.

[0084] Ammonia and hydrofluoric acid or ammonium fluoride can be used to perform the chemical etching process. Other chemicals that can be used include, but are not limited to, ammonia and water, NHF, NH4F, hydrogen fluoride, or hydrogen chloride.

[0085] In one embodiment, the etching process may be performed using ammonium fluoride. When the SAM is formed on the sidewalls, the carbon-based groups prevent the ammonium fluoride from interacting with the sidewalls. Thus, the carbon-based groups act as a blocking agent in the chemical etching process of the trench.

[0086] The above description proposes many specific details, such as examples of specific systems, components, methods, etc., in order to provide a good understanding of several embodiments of the present invention. However, it is obvious to those skilled in the art that at least some embodiments of the present invention can be practiced without these specific details. In other cases, known components or methods are not described in detail, or are presented in the form of simple block diagrams to avoid unnecessarily obscuring the present invention. Therefore, the specific details set forth are merely exemplary. Specific embodiments may differ from these exemplary details and are still considered to be within the scope of the present invention.

[0087] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment. Therefore, the words "in one embodiment" or "in an embodiment" appearing in various places throughout this specification do not necessarily refer to the same embodiment. In addition, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". When the term "about" or "approximately" is used herein, this is intended to mean that the nominal value presented is accurate within a range of ±10%.

[0088] Although the operations of the methods herein are shown and described in a particular order, the order of the operations of each method may be changed so that some operations may be performed in a reverse order, or so that some operations may be performed at least partially in synchronization with other operations. In another embodiment, the instructions or sub-operations of different operations may be intermittent and / or alternating.

[0089] It should be understood that it is hoped that the above description is illustrative, rather than restrictive. After reading and understanding the above description, many other embodiments will be apparent to those skilled in the art. Therefore, the scope of the present invention should be determined with reference to the complete scope of the equivalent technical solutions assigned by the attached claims and these claims.

Claims

1. A method comprising: placing a substrate into the chamber, the substrate comprising a layer, the layer comprising at least one trench formed in the layer, the at least one trench having a top surface, a bottom surface, and at least one sidewall; depositing a 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; as well as The bottom surface of the trench is etched using an etch chemistry, wherein the second film protects the at least one sidewall from the etch chemistry. 2 . The method of claim 1 , wherein the second film comprises a self-assembled monolayer (SAM) that is not formed on the polymer film.

3. The method of claim 1, wherein the layer comprises silicon, silicon nitride, damaged silicon nitride, silicon oxide, or a low-κ material, wherein the substrate comprises silicon. The method of claim 1 , wherein the bottom surface has a U-shaped profile and includes the substrate.

5. The method according to claim 1, further comprising: After the etching is performed, the second film is removed. 6 . The method of claim 1 , wherein removing the polymer film comprises at least one of heating the polymer film or exposing the polymer film to plasma. The method of claim 1 , wherein the polymer film comprises a carbon-based compound.

8. The method according to claim 7, wherein the carbon-based compound comprises at least one precursor, wherein the at least one precursor is selected from Formula 1 and a combination of Formula A and Formula B, wherein Formula 1 is one of the following: Wherein R can be H, alkyl or aryl, and R' can be Cl, Br, IOR, OH, H NR2, Si(NCO)4, Si(NCS)4, or wherein R may be H, alkyl or aryl, and R' may be Cl, Br, IOR, OH, H NR2; and Wherein Formula 2 is one of the following: in, R, R' and R" may each independently be H, alkyl or aryl; or Wherein, R, R' and R" can each independently be H, an alkyl group or an aryl group.

9. The method of claim 7, wherein the carbon-based compound comprises a precursor selected from Formula A. in, Y is a hydroxyl group, an aldehyde group, a keto group, an acid group, an amino group, an isocyanate group, a thiocyanate group or an acid chloride group. Formula A includes two reactive 10. The method of claim 7, wherein the carbon-based compound is terephthalaldehyde.

11. The method of claim 1, wherein the second film comprises at least one of: a silyl amide, a silyl halide, a silyl alkoxide, or a cyclic silyl amide.

12. The method according to claim 11, wherein the silylamide is a compound according to formula III, the silylhalide is a compound according to formula IV, the silylalkoxide is a compound according to formula V, and the cyclic silylamide is a compound having a C3-C8 ring: R n Si(NR'2) (4-n) Formula IV, wherein In Formula IV, each R is independently a C1-C18 alkyl, C1-C18 alkenyl, C1-C18 alkynyl, C1-C18 aliphatic or C1-C18 aromatic, and n=1-3; R n SiX (4-n) Formula V, wherein, in Formula V, R is independently C1-C18 alkyl, C1-C18 alkenyl, C1-C18 alkynyl, C1-C18 aliphatic, C1-C18 aromatic, X is Cl, Br or I, and n=1-3; and R n Si(OR') (4-n) Formula VI, wherein in Formula VI, R is each independently C1-C18 alkyl, C1-C18 alkenyl, C1-C18 alkynyl, C1-C18 aliphatic or C1-C18 aromatic, and n=1-3. 13 . The method of claim 1 , wherein the polymer film is a flowable film that flows to the bottom surface of the at least one trench at a temperature within a target temperature range during deposition of the flowable film.

14. The method of claim 1, wherein the at least one sidewall of the at least one trench is protected from the etching chemistry by the second film so as not to be etched.

15. The method according to claim 1, further comprising: Oxide is removed from the bottom surface of the at least one trench during the etching.

16. The method of claim 1 wherein the etch chemistry comprises ammonium fluoride.

17. A method comprising: placing a substrate into the chamber, the substrate comprising a layer, the layer comprising at least one trench formed in the layer, the at least one trench having a top surface, a bottom surface, and at least one sidewall; depositing a 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; as well as A second film is selectively formed on the layer without forming the second film on the polymer film. 18 . The method of claim 17 , wherein the polymer film is a flowable film that flows to the bottom surface of the at least one trench at a temperature within a target temperature range during deposition of the flowable film.

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

20. A method comprising: placing a substrate into the chamber, the substrate comprising a layer, the layer comprising at least one trench formed in the layer, the at least one trench having a top surface, a bottom surface, and at least one sidewall; depositing a 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; as well as 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, wherein the etching process includes applying ammonium fluoride to the substrate; The step of 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 sidewall.

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