A method for forming shape-selective silicon oxide films by a periodic plasma-enhanced deposition process.

Abstract

To provide: methods for forming a topographically selective silicon oxide film by a cyclical plasma-enhanced deposition process; and methods of forming a silicon oxide film selectively either over horizontal surfaces of a non-planar substrate or over vertical surfaces of a non-planar substrate.SOLUTION: The methods include: forming a topographically selective silicon oxide film on a substrate by a cyclical plasma-enhanced deposition process; forming a silicon oxide film by a plasma enhanced atomic layer deposition (PEALD) process or a cyclical plasma-enhanced chemical vapor deposition (cyclical PECVD) process; and forming a silicon oxide film selectively either over horizontal surfaces of a non-planar substrate or over vertical surfaces of a non-planar substrate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure generally relates to a method of forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process and to a particular method of forming a silicon oxide film either selectively on a horizontal surface of a non-planar substrate or selectively on a vertical surface of a non-planar substrate. The present disclosure also generally relates to a shape-selective periodic plasma-enhanced deposition process, such as a plasma-enhanced atomic layer deposition (PEALD) process, and a periodic plasma-enhanced chemical vapor deposition (PECVD) process.

Background Art

[0002] In the field of semiconductor device technology, a silicon oxide film may be utilized during the manufacture of semiconductor integrated circuits. For example, a silicon oxide film can be utilized as an insulating material during the manufacture of semiconductor device structures, such as transistors, memory cells, logic devices, memory arrays, and the like.

[0003] In a typical silicon oxide film deposition process, for example, a substrate can be heated to a temperature above about 400 °C and subsequently exposed to tetraethyl orthosilicate (TEOS) vapor to deposit a layer of silicon dioxide on the surface of the substrate. Such a typical silicon oxide film deposition method can deposit a silicon oxide film that is relatively conformal over the entire surface of the substrate, i.e., the silicon oxide film has a relatively uniform thickness over the entire shape of the substrate.

[0004] However, in the case of next-generation technology nodes, it may be beneficial to provide the ability to form shape-selective silicon oxide, for example, to form a silicon oxide film on a non-planar substrate surface that is selective with respect to a first plane of the non-planar substrate relative to a second plane of the non-planar substrate.

[0005] Therefore, the method is preferable for forming a shape-selective silicon oxide film, particularly for selectively forming a silicon oxide film on a horizontal surface of a non-planar substrate or selectively forming a silicon oxide film on a vertical surface of a non-planar substrate. [Overview of the Initiative] [Means for solving the problem]

[0006] According to at least one embodiment of the present disclosure, a method is provided for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process. The method includes supplying a non-planar substrate having one or more horizontal surfaces and one or more vertical surfaces into a reaction chamber; contacting the non-planar substrate with a gas-phase reactant comprising a silicon component, a carbon component, and a hydrogen component; contacting the non-planar substrate with reactants generated from a plasma produced from a gas comprising an oxygen precursor and a noble gas; and forming a silicon oxide film selectively on the horizontal surface of the non-planar substrate or selectively on the vertical surface of the non-planar substrate.

[0007] Embodiments of the present disclosure also include a method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process. The method includes supplying a non-planar substrate having one or more horizontal surfaces and one or more vertical surfaces into a reaction chamber; contacting the non-planar substrate with a first reaction species generated from a first gas comprising at least a gas-phase reactant comprising a silicon component, a carbon component, and a hydrogen component; contacting the non-planar substrate with a second reaction species generated from a second gas comprising at least an oxygen precursor and a noble gas; and forming a silicon oxide film either selectively on the horizontal surface of the non-planar substrate or selectively on the vertical surface of the non-planar substrate.

[0008] Embodiments of the present disclosure also include a method for forming a shape-selective silicon oxide film on a non-planar substrate by a plasma-enhanced atomic layer deposition process. The method includes contacting the non-planar substrate with a gas-phase reactant comprising a silicon component, a carbon component, and a hydrogen component; contacting the non-planar substrate with a plurality of ions comprising at least an oxygen ion, wherein the plurality of ions collide with the substrate in a direction substantially perpendicular to the horizontal plane of the substrate; and selectively depositing the silicon oxide film on the horizontal plane of the non-planar substrate relative to the vertical plane of the non-planar substrate.

[0009] For the purpose of summarizing the invention and its advantages achieved beyond the prior art, several specific purposes and advantages of the invention are described above herein. Naturally, it should be understood that not all of these purposes or advantages are necessarily achieved by any particular embodiment of the invention. Therefore, those skilled in the art will recognize that the invention may be embodied or practiced in a manner that achieves or optimizes one or a group of advantages, for example, as taught or suggested herein, without necessarily achieving other purposes or advantages as may be taught or suggested herein.

[0010] All of these embodiments are intended to be within the scope of the present invention disclosed herein. To those skilled in the art, these and other embodiments will be readily apparent from the following detailed description of certain embodiments with reference to the accompanying drawings, and the present invention is not limited to any particular embodiment disclosed.

[0011] This specification particularly points out and explicitly asserts embodiments of the present invention and concludes in the claims, but the advantages of the embodiments of this disclosure may be more readily apparent from the description of certain embodiments of this disclosure when read in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 is a schematic diagram of an exemplary apparatus that can be used to carry out the periodic plasma-enhanced deposition method of this disclosure. [Figure 2] Figure 2 is a process flow diagram that includes an exemplary process for forming a shape-selective silicon oxide film by a PEALD process according to an embodiment of the present disclosure. [Figure 3] Figure 3 shows an exemplary unit deposition cycle of the PEALD process for forming a shape-selective silicon oxide film according to an embodiment of the present disclosure. [Figure 4] Figure 4 is a process flow diagram including an exemplary process for forming a shape-selective silicon oxide film by a periodic PECVD process according to an embodiment of the present disclosure. [Figure 5] Figure 5 shows an exemplary unit deposition cycle of a periodic PECVD process for forming a shape-selective silicon oxide film according to embodiments of the present disclosure. [Figure 6] Figure 6 shows another exemplary unit deposition cycle of a periodic PECVD process for forming a shape-selective silicon oxide film according to embodiments of the present disclosure. [Figure 7] Figure 7 shows another exemplary unit deposition cycle of a periodic PECVD process for forming a shape-selective silicon oxide film according to embodiments of the present disclosure. [Figure 8] Figures 8A and 8B show exemplary non-planar substrates before and after shape-selective silicon oxide formation according to embodiments of the present disclosure, where the silicon oxide film is selectively formed on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate. [Figure 9] Figures 9A and 9B are scanning tunneling electron microscope (STEM) images of exemplary non-planar substrates after shape-selective formation of a silicon oxide film according to embodiments of the present disclosure, demonstrating that the silicon oxide film is selective for deposition on a horizontal plane compared to a vertical plane. [Figure 10] Figure 10 shows the changes in both horizontal and vertical silicon oxide film thickness as the number of unit deposition cycles increases in an exemplary shape-selective PEALD process according to embodiments of the present disclosure. [Figure 11]Figure 11 is a process flow diagram that includes an exemplary process for forming a shape-selective silicon oxide film by a PEALD process according to an embodiment of the present disclosure. [Figure 12] Figure 12 shows data representing the etching thickness of an exemplary silicon oxide film as a function of plasma contact time. [Figure 13] Figure 13 shows an exemplary unit deposition cycle of the PEALD process for forming a shape-selective silicon oxide film according to an embodiment of the present disclosure. [Figure 14] Figure 14 is a process flow diagram illustrating an exemplary process for forming a shape-selective silicon oxide film by combining periodic plasma-enhanced deposition and selective etching according to embodiments of the present disclosure. [Figure 15] Figures 15A and 15B show exemplary non-planar substrates after shape-selective deposition of a silicon oxide film by shape control of a silicon oxide composition according to embodiments of the present disclosure, and exemplary non-planar substrates in which the silicon oxide film located on a horizontal plane is selectively removed from the silicon oxide film located on a vertical plane by contacting the silicon oxide film with an etchant. [Modes for carrying out the invention]

[0013] Naturally, the elements in the figures are illustrative for simplification and clarity and are not necessarily drawn to actual size. For example, the dimensions of some of the elements in the figures may be exaggerated relative to others to help improve understanding of the illustrated embodiments of this disclosure.

[0014] Certain embodiments and examples are disclosed below, but it will be understood by those skilled in the art that they extend beyond the embodiments and / or uses of the present invention specifically disclosed herein, as well as obvious modifications and equivalents thereof. Therefore, the scope of the disclosed invention is not intended to be limited by the specific embodiments described below.

[0015] As used herein, the term "shape-selective" can refer to having selectivity of a non-planar first plane with respect to a non-planar second plane and forming a film of material on a non-planar substrate, i.e., forming a thicker material on the first plane compared to the thickness of the material on the second plane.

[0016] Furthermore, the "selectivity" of a shape-selective process can be expressed as the ratio of the amount of material formed on the first plane of a non-planar substrate to the combined amount of material formed on the first and second planes. For example, for a horizontally selective process, if a shape-selective process forms 10 nanometers of material on the horizontal plane of a non-planar substrate and 1 nanometer of material on the vertical plane of the non-planar substrate, the shape-selective process is considered to have 90% selectivity. As another example, for a vertically selective process, if a shape-selective process forms 10 nanometers of material on the vertical plane of a non-planar substrate and 1 nanometer of material on the horizontal plane of the non-planar substrate, the shape-selective process is considered to have 90% selectivity.

[0017] As used herein, the term "substrate" may refer to any underlying material or materials that may be used or on which a device, circuit, or film may be formed.

[0018] As used herein, the term "gas" means a vapor or vaporized solid and / or liquid and can be composed of a single gas or a mixture of gases.

[0019] As used herein, the term "reactant species" may refer to one or more species generated by plasma excitation of a gas and can include, but is not limited to, ions, radicals, and excited species.

[0020] As used herein, the term "silicon oxide film" may refer to a film of a material containing at least one silicon component and an oxygen component. The term "silicon oxide film" may, but is not limited to, contain other components in addition to at least the silicon and oxygen components, including carbon, nitrogen, and hydrogen components. For example, silicon oxide films include silicon dioxide (SiO2), silicon monoxide (SiO2), and silicon dioxide (SiO2). x (wherein x may be less than 2), may also contain silicon oxycarbide or doped silicon oxide.

[0021] As used herein, the terms “film” and “thin film” may refer to any continuous or discontinuous structures and materials deposited by the methods disclosed herein. Examples of “film” and “thin film” include 2D materials, nanolaminates, nanorods, nanotubes, or nanoparticles, or planar partial or complete molecular layers, or partial or complete atomic layers, or clusters of atoms and / or molecules. “Film” and “thin film” may include materials or layers having pinholes, but are still at least partially continuous.

[0022] As used herein, the term “periodic plasma-enhanced deposition process” refers to a gas-phase deposition process comprising one or more repeating unit deposition cycles, specifically multiple consecutive repetitions of a unit deposition cycle, the unit deposition cycle comprising the use of one or more reactive species generated from a plasma.

[0023] As used herein, “Plasma-Enhanced Atomic Layer Deposition” (PEALD) may refer to a gas-phase deposition process in which deposition cycles, preferably multiple sequential deposition cycles, are carried out in a reaction chamber. Typically, during each unit deposition cycle, a precursor is chemisorbed onto the deposition surface (e.g., a substrate surface or a previously deposited underlayment surface, e.g., a material deposited using a previous PEALD cycle) to form a monolayer or sub-monolayer that does not readily react with another precursor (i.e., a self-controlled reaction). Subsequently, reactive species generated by the plasma produced from one or more precursors are introduced into or generated within the reaction chamber for use in converting the chemisorbed precursors into a desired material on the deposition surface. Furthermore, a purging step may be utilized during each unit deposition cycle to remove excess precursors and reactive species from the reaction chamber after the conversion of the chemisorbed precursors, and / or excess reactants, reactive species, and / or reaction by-products from the reaction chamber.

[0024] As used herein, “periodic plasma-enhanced chemical vapor deposition” (periodic PECVD) can refer to a vapor deposition process in which deposition cycles, preferably multiple consecutive deposition cycles, are carried out within a reaction chamber. Typically, during each unit deposition cycle, one or more reactive species can be generated by plasma produced by the continuous application of either RF power or pulses of two or more RF powers. In contrast to PEALD processes, periodic PECVD processes typically do not employ chemisorption of vapor-phase reactants and the subsequent conversion of the chemisorbed molecular layer into the desired material. Periodic plasma-enhanced chemical vapor deposition is sometimes also called pulsed plasma-enhanced chemical vapor deposition.

[0025] As used herein, the term “horizontal plane” can refer to a plane of a substrate that extends essentially horizontally, and essentially horizontal can include a plane of a substrate that is within about 30 degrees from the horizontal, or within about 15 degrees, or even within 5 degrees.

[0026] As used herein, the term “vertical plane” can refer to a plane of a substrate that extends essentially vertically, and essentially vertical can include a plane of a substrate that is within about 30 degrees, or about 15 degrees, or even 5 degrees from the vertical.

[0027] It should be noted that while many exemplary materials are given through embodiments of this disclosure, the chemical formulas given for each exemplary material should not be interpreted as restrictive, and the non-restrictive exemplary materials given should not be limited by any exemplary stoichiometry.

[0028] In this specification, the terms “on” or “over” can be used to describe relative positional relationships. Another element or layer may be directly on the layer being referred to, or another layer (intermediate layer) or element may be interposed between them, or a layer may be positioned on the layer being referred to but not completely covering its surface. Thus, unless the term “directly” is used separately, the terms “on” or “over” will be interpreted as relative concepts. Similarly, the terms “under,” “underlying,” or “below” will be interpreted as relative concepts.

[0029] Embodiments of the present disclosure may include a method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process. Specifically, the shape-selective deposition method disclosed herein can selectively form a silicon oxide film on a first plane of a non-planar substrate relative to a second plane of the non-planar substrate. For example, the silicon oxide film can be selectively formed on a horizontal plane of the substrate relative to a vertical plane of the substrate ("horizontal plane selection process"). Alternatively, the silicon oxide film can be selectively formed on a vertical plane of the substrate relative to a horizontal plane of the substrate ("vertical plane selection process").

[0030] Embodiments of the present disclosure can provide a shape-selective forming process for forming a silicon oxide film on a horizontal plane relative to a vertical plane by a direct shape-selective deposition process. Furthermore, embodiments of the present disclosure can provide a shape-selective forming process for forming a silicon oxide film on a plane perpendicular to a horizontal plane by deposition of a silicon oxide film with shape control of the silicon oxide film properties, and the deposited silicon oxide film can come into contact with an etchant that can selectively remove silicon oxide films placed on the horizontal plane of a non-planar substrate.

[0031] Next-generation semiconductor device processes may require non-conformal, shape-selective deposition of silicon oxide films. For example, a silicon oxide film selectively formed on a horizontal surface of a substrate, such as the horizontal surface of a trench structure, can be used as a sacrificial etching mask due to the selective etching resistance of the silicon oxide film to plasma etching.

[0032] Non-conformal shape-selective film deposition has been demonstrated by numerous methods. For example, a combination of conformal silicon oxide deposition and wet chemical etching has been studied, where the deposition of the silicon oxide film is adjusted to obtain a low-quality film on the vertical surface of the substrate, for example, on the sidewalls of a trench structure. In such embodiments, the vertical silicon oxide film can be selectively removed by the etchant due to the much higher etching rate of the silicon oxide film on the vertical surface of a non-planar substrate compared to the silicon oxide film on the horizontal surface of a non-planar substrate.

[0033] Furthermore, the deposition of non-conformal, shape-selective films can be achieved by using either growth inhibitors or growth promoters. However, the use of growth inhibitors / promoters reduces the throughput of the substrate being processed, as it adds a chemical wet etching step required to achieve the desired selectivity. In addition, processing costs can increase due to the cost of the inhibitor / promoter chemicals and the expenses of the optimization period required to achieve activation / inhibition of the target plane.

[0034] The shape-selective formation process of the present disclosure may be performed in a reaction chamber associated with a PEALD or PECVD apparatus, comprising appropriate hardware for pulsing RF power and continuously supplying two or more precursors to the reaction chamber. In some embodiments of the present disclosure, the reaction chamber used for the formation of a shape-selective silicon oxide film can supply an anisotropic plasma, i.e., a plasma in which at least ionized species are accelerated in a substantially uniform direction, as opposed to an isotropic plasma in which excited species move in random directions. In some embodiments, the reaction chamber used for the formation of a shape-selective silicon oxide film can generate a plasma, for example, a capacitively coupled plasma (CCP) excited by applying RF power to one of two electrodes. In some further embodiments, inductively coupled plasma (ICP), electron cyclotron resonance (ECR) plasma, microwave surface plasma, helicon wave plasma, etc., may be used as the plasma, and a bias voltage is applied between the electrodes as necessary to increase the DC bias between the plasma and the electrodes.

[0035] As a non-limiting example, shape-selective silicon oxide film formation is possible by adjusting the impact of the plasma-exciting gas by applying a voltage between two electrodes arranged parallel to a non-planar substrate. The plasma is a partially ionized gas with a high free electron content (approximately 50%), and when the plasma is excited by applying an AC voltage between parallel electrodes, the ions generate a self-DC bias (V) between the plasma sheath and the lower electrode. DCThe ions are accelerated by the following: The accelerated ions irradiate a non-planar substrate placed on the lower electrode in a direction substantially perpendicular to the horizontal plane of the substrate, i.e., perpendicular to the horizontal plane of the lower electrode (ion incidence direction). The plasma impact can be expressed in terms of plasma density or the kinetic energy of the ions. Plasma density can be adjusted mainly by adjusting the pressure and RF power in the reaction chamber (lower pressure and higher RF power result in higher plasma density). Plasma density can also be adjusted at a low frequency (e.g., less than 1 MHz) to which the ions are set to follow by applying a DC bias voltage or AC voltage.

[0036] The periodic plasma-enhanced deposition process of the present disclosure can form a shape-selective silicon oxide film by repeating a unit deposition cycle once or more times, the unit deposition cycle may include the generation of reactive species from the plasma. In non-limiting examples, the deposition cycle may be carried out using a suitable apparatus, for example, the apparatus 100 illustrated in Figure 1. For example, Figure 1 is a schematic diagram of an exemplary PEALD apparatus 100, preferably integrated with a control device programmed to perform the sequence described below, which can be used in some embodiments of the present invention. In this figure, a pair of conductive plate electrodes 104, 102 are provided parallel to each other inside the reaction chamber 103 (reaction region), and the plasma is excited between the electrodes by applying RF power (e.g., 13.56 MHz or 27 MHz) 120 to one side and electrically grounding the other side 112. A temperature controller is provided on the lower stage 102 (lower electrode) to maintain the temperature of the substrate 101 placed on it at a predetermined constant temperature. The upper electrode 104 also functions as a showerhead plate, and the reactant gas (and noble gas) and precursor gas are introduced into the reaction chamber 103 through gas lines 121 and 122, and through the showerhead plate 104, respectively.

[0037] Furthermore, a circular duct 113 with an exhaust line 107 is provided inside the reaction chamber 103, through which the gas inside the reaction chamber 103 111 is exhausted. In addition, a diluent gas is introduced into the reaction chamber 103 through a gas line 123. Furthermore, a transport chamber 105 located below the reaction chamber 103 is provided with a seal gas line 124 for introducing a seal gas into the inside of the reaction chamber 103 111 via the inside of the transport chamber 105 116 (transport area), and a separation plate 114 is provided for separating the reaction area and the transport area (gate valves through which wafers are transported into and out of the transport chamber 105 are omitted from this figure). The transport chamber also includes an exhaust line 106. In some embodiments, the deposition and surface treatment of the multi-element film are carried out in the same reaction space, so that all processes can be carried out continuously without exposing the substrate to air or other oxygen-containing atmospheres. In some embodiments, a remote plasma device can be used to excite the gas.

[0038] In some embodiments of this disclosure, a shape-selective silicon oxide film can be formed using a periodic plasma-enhanced deposition process, such a process may include plasma-enhanced atomic layer deposition (PEALD) or periodic plasma-enhanced chemical vapor deposition (periodic PECVD). Briefly, a non-planar substrate or workpiece is placed in a reaction chamber, heated to a deposition temperature, and carried out by alternating surface reactions, i.e., one or more repetitions of a unit deposition cycle. In some embodiments, each unit deposition cycle (i.e., a PEALD cycle or a periodic PECVD cycle) includes at least two distinct phases.

[0039] In the first phase, a gas-phase reactant or plasma generated from a gas-phase reactant can be supplied into the reaction chamber and come into contact with the surface of a non-planar substrate. This reactant or plasma-generating reactant is also referred herein as “silicon precursor,” “silicon-containing precursor,” “silicon reactant,” or “silicon reactant,” and may include, for example, a gas-phase reactant or plasma generated from a gas-phase reactant containing silicon, carbon, and hydrogen components.

[0040] In some embodiments of this disclosure, the silicon reactant essentially consists of a silicon component, a carbon component, and a hydrogen component. In some embodiments, the silicon reactant may include alkylsilanes, such as dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane, triethylsilane, tetraethylsilane, t-butylsilane (and its derivatives), or silicon reactants containing two silicon atoms, such as hexamethyldisilane. In some embodiments, the silicon reactant may include arylsilanes, such as phenylsilane, diphenylsilane, triphenylsilane, tetraphenylsilane, dibenzylsilane, tripenzylsilane, or tetrabenzylsilane. In some embodiments, the silicon reactant may include aralkylsilanes, such as trimethyl-(3-methylphenyl)silane or dimethyl(4-methylphenyl)silane.

[0041] In some embodiments of this disclosure, the silicon reactant may further comprise at least one of a nitrogen component or an oxygen component. For example, the silicon reactant may comprise at least one of an alkylalkoxysilane or an alkylaminosilane. In some embodiments, the silicon reactant may comprise an alkylalkoxysilane, such as methyltrimethoxysilane, ethoxy(trimethyl)silane, diethyl-methyl-ethoxysilane, ethyl(dimethyl)-ethoxysilane, tert-butyl-triethoxysilane, or butyl(trimethoxy)silane. In some embodiments, the silicon reactant may comprise an alkylaminosilane, such as tris(dimethylamino)ethylsilane.

[0042] In some embodiments, the silicon reactant is given by the following formula (I):

[0043] [ka]

[0044] (wherein R1, R2, R3, and R4 may include silicon, carbon, and hydrogen, and at least one of R1, R2, R3, and R4 may not be hydrogen or silicon, and R1, R2, R3, and R4 may not contain oxygen, nitrogen, or halogens) can be represented by:

[0045] In some embodiments, the silicon reactant is given by the following formula (II-IV):

[0046] [ka]

[0047] It can be represented by (wherein R1, R2, R3, and R4 may include silicon, carbon, and hydrogen, and at least R3 may not be hydrogen or silicon, and R1, R2, R3, and R4 may not contain oxygen, nitrogen, or halogens).

[0048] In some embodiments, the silicon reactant is given by the following formula (V-VII):

[0049] [ka]

[0050] It can be represented by (wherein R1, R2, R3, and R4 may include silicon, carbon, and hydrogen, and at least R3 may not be hydrogen or silicon, and R1, R2, R3, and R4 may not contain oxygen, nitrogen, or halogens).

[0051] In the second phase, a second reactant containing reactant species is supplied, allowing the silicon reactant to be converted into a silicon oxide film. In some embodiments of this disclosure, the second reactant may include reactant species generated from a plasma produced from a gas containing an oxygen precursor and a noble gas.

[0052] In some embodiments, the oxygen precursor may include at least one of molecular oxygen (O2), carbon dioxide (CO2), or nitrous oxide (N2O). In some embodiments, the noble gas may include at least one of argon, nitrogen, or helium. In some embodiments, the flow rate ratio of the noble gas to the oxygen precursor may be greater than 1, greater than 2, or even greater than 3.

[0053] Plasmas generated from a gas consisting solely of oxygen precursors are generally isotropic and primarily contain oxygen radicals that are unaffected by the electric field and traverse in substantially random directions. Embodiments of the present disclosure generate plasma from a gas containing oxygen precursors and noble gases, and the resulting plasma may be rich in ions that may be affected by the electric field, in particular multiple ions that are anisotropically accelerated downward toward a non-planar substrate in a substantially vertical direction and irradiate or collide with the non-planar substrate in a direction substantially perpendicular to the horizontal plane of the substrate, i.e., perpendicular to the horizontal plane of the lower electrode of the deposition apparatus. For example, the ion incidence direction may be substantially perpendicular to the lower electrode 102 of apparatus 100 in Figure 1. In such embodiments of the present disclosure, the ion collision rate, i.e., the proportion of multiple ions that affect the non-planar substrate, is greater on the horizontal plane of the non-planar substrate compared to the vertical plane of the non-planar substrate, resulting in shape-selective deposition of silicon oxide films on the horizontal plane of the substrate compared to the vertical plane of the substrate. Furthermore, the difference in ion collision rates affecting the horizontal and vertical planes can lead to shape control of the silicon oxide film composition; that is, the composition of the silicon oxide film on the horizontal plane may differ from that on the vertical plane. This allows for vertically selective silicon oxide film formation by selective etching of the silicon oxide film placed on the horizontal plane of a non-planar substrate.

[0054] Horizontal plane selective silicon oxide formation process In some embodiments of the present disclosure, a method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process may include selectively forming a silicon oxide film on the horizontal surface of a non-planar substrate relative to the vertical surface of the non-planar substrate, i.e., a thicker thickness of silicon oxide material can be formed on the horizontal surface of the non-planar substrate compared to the thickness of silicon oxide material that can be formed on the vertical surface of the non-planar substrate.

[0055] In some embodiments of the present disclosure, a horizontally selective silicon oxide formation process can be achieved by selectively depositing a silicon oxide film directly onto a horizontal plane relative to a vertical plane. In some embodiments, the horizontally selective silicon oxide deposition process of the present disclosure may include a periodic plasma-enhanced deposition process, such as a plasma-enhanced atomic layer deposition (PEALD) process or a periodic plasma-enhanced chemical vapor deposition (periodic PECVD) process.

[0056] Accordingly, embodiments of the present disclosure may include a method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process. The method includes supplying a non-planar substrate having one or more horizontal surfaces and one or more vertical surfaces into a reaction chamber; contacting the non-planar substrate with a gas-phase reactant comprising silicon components, carbon components, and hydrogen components; contacting the non-planar substrate with reactants generated from a plasma produced from a gas comprising an oxygen precursor and a noble gas; and forming a silicon oxide film either selectively on the horizontal surface of the non-planar substrate or selectively on the vertical surface of the non-planar substrate.

[0057] Embodiments of the present disclosure also include a method for forming a shape-selective silicon oxide film on a non-planar substrate by a plasma-enhanced atomic layer deposition process. The method includes contacting the non-planar substrate with a gas-phase reactant comprising a silicon component, a carbon component, and a hydrogen component; contacting the non-planar substrate with a plurality of ions comprising at least an oxygen ion, wherein the plurality of ions collide with the substrate in a direction substantially perpendicular to the horizontal plane of the non-planar substrate; and selectively depositing the silicon oxide film on the horizontal plane of the non-planar substrate relative to the vertical plane of the non-planar substrate.

[0058] A non-limiting example of a periodic plasma-enhanced deposition process that can be used to form a horizontally selective silicon oxide film is plasma-enhanced atomic layer deposition (PEALD). Briefly, a substrate or workpiece is placed in a reaction chamber and a series of alternating surface reactions are carried out. In some embodiments, a silicon oxide film can be formed by repeating a self-controlled PEALD cycle.

[0059] An exemplary PEALD process for forming a horizontally selective silicon oxide film is illustrated with reference to Figure 2. The exemplary PEALD process 200 may include two phases: the first phase involves contacting the substrate with a gas-phase reactant containing silicon, carbon, and hydrogen components, and the second phase involves contacting the substrate with reactant species generated from a plasma.

[0060] Referring in more detail to Figure 2, an exemplary process 200 can be initiated by a process block 210 which includes supplying the substrate into a reaction chamber and heating the substrate to a suitable deposition temperature.

[0061] In some embodiments, the substrate may include, but is not limited to, one or more materials and material surfaces, including semiconductor materials, dielectric materials, and metallic materials. For example, the substrate may include, but is not limited to, semiconductor materials such as silicon (Si), germanium (Ge), germanium tin (GeSn), silicon germanium (SiGe), silicon germanium tin (SiGeSn), silicon carbide (SiC), or Group III-V semiconductor materials.

[0062] In some embodiments of the present disclosure, the substrate may include patterned non-planar substrates that include high aspect ratio features, such as trench structures, vertical gap features, and / or fin structures. The term “gap feature” can refer to an opening or cavity located between opposing inclined sidewalls or two protrusions extending perpendicularly from the surface of the substrate, or between opposing inclined sidewalls of a recess extending perpendicularly into the surface of the substrate, and such gap features may be called “vertical gap features” that include both horizontal and vertical planes. In some embodiments, a vertical gap feature may have an aspect ratio (height:width) greater than 2:1, or greater than 5:1, or greater than 10:1, or greater than 25:1, or greater than 50:1, or even greater than 100:1, where, as used in this example, “greater” refers to a longer distance in the height of the gap feature.

[0063] In some embodiments, the substrates to be deposited are loaded into the reaction chamber. In some embodiments, the reaction chamber can form part of a cluster tool on which various different processes are performed in the formation of the semiconductor device structure. In some embodiments, a flow reactor may be used. In some embodiments, a showerhead type reactor may be used. In some embodiments, a space-dividing reactor may be used. In some embodiments, a single-wafer PEALD reactor capable of mass production may be used. In other embodiments, a batch reactor containing multiple substrates may be used. For embodiments in which a batch PEALD reactor is used, the number of substrates may be in the range of 10 to 200, or in the range of 50 to 150, or further in the range of 100 to 130.

[0064] In some embodiments, the exposed surface of the substrate may be pre-treated as needed to provide reaction sites that react with the first phase of the PEALD process. In some embodiments, a separate pre-treatment step is not required. In some embodiments, the substrate is pre-treated to obtain a desired surface termination by, for example, exposing the substrate surface to a pre-treatment plasma.

[0065] In some embodiments of the present disclosure, the substrate placed in the reaction chamber may be heated to a desired deposition temperature for a subsequent periodic deposition stage 205 of the exemplary PEALD process 200 (Figure 2). For example, the substrate may be heated to a substrate deposition temperature of less than about 600°C, or less than about 550°C, or less than about 500°C, or less than about 450°C, or less than about 400°C, or less than about 350°C, or less than about 300°C, or even less than about 250°C. In some embodiments of the present disclosure, the substrate deposition temperature during the exemplary plasma-enhanced atomic layer deposition process 200 may be between about 150°C and about 600°C.

[0066] In addition to controlling the temperature of the substrate, the pressure within the reaction chamber can also be adjusted to allow the deposition of the desired silicon oxide film. In some embodiments, the occupancy density and the properties of the reactants generated in the plasma can also be controlled by adjusting the pressure within the reaction chamber. Thus, in some embodiments, the pressure within the reaction chamber during the exemplary PEALD process 200 can be adjusted to a pressure greater than 150 Pascals, or greater than 300 Pascals, or greater than 450 Pascals, or greater than 600 Pascals, or even greater than 800 Pascals. For example, in some embodiments, the pressure within the reaction chamber during the exemplary PEALD process 200 may be adjusted between 150 Pascals and 800 Pascals.

[0067] Once the substrate temperature is set to the desired deposition temperature, the pressure in the reaction chamber is adjusted as needed, and the exemplary process 200 can be continued by a periodic deposition stage 205 which may include supplying one or more deposition gases to the reaction chamber, the deposition gases may include gas-phase reactants, purge gases, carrier gases, and gases used to generate reactive species from the plasma.

[0068] In short, in the first phase of the periodic deposition stage 205, the gas-phase reactants include silicon, carbon, and hydrogen components, and the “silicon precursor” may be “pulsed” into the reaction chamber, where the term “pulsed” can be understood as including supplying the reactants into the reaction chamber for a predetermined time. The term “pulsed” does not limit the length or duration of the pulse, but the pulse can be of any length. In some embodiments, in addition to the silicon precursor, the gas mixture may be continuously supplied into the reaction chamber during the periodic deposition stage 205 of the exemplary PEALD process 100. In some embodiments, the gas mixture may include both a gas mixture for generating reactants that are utilized during the second stage of the PEALD process 200, and may also be used as a purge gas to remove excess reactants, reactants, and reaction byproducts from the reaction chamber.

[0069] More specifically, the periodic deposition stage 205 of the exemplary PEALD process 200 can be continued by a process block 220 which includes contacting the substrate with a gas-phase reactant containing silicon components, carbon components, and hydrogen components, i.e., a silicon precursor.

[0070] In some embodiments, a silicon precursor may be supplied to the substrate first. After the initial surface termination, if necessary or desirable, a silicon precursor pulse may be supplied to the substrate. According to some embodiments, the silicon precursor may be supplied to the reaction chamber together with a carrier gas flow. In some embodiments, the silicon precursor may include volatile silicon species that react with the surface of the substrate. The silicon precursor pulse can self-saturate the substrate surface so that excess components of the silicon precursor pulse do not further react with the molecular layer formed by this process.

[0071] The silicon precursor pulse is preferably supplied as a gas-phase reactant. The silicon precursor gas may be considered "volatile" for the purposes of this disclosure if the seeds exhibit sufficient vapor pressure under process conditions and transport the seeds to the substrate surface at a sufficient concentration to saturate the exposed surface.

[0072] In some embodiments of this disclosure, the gas-phase reactant essentially consists of a silicon component, a carbon component, and a hydrogen component. In some embodiments, the gas-phase reactant may also include alkylsilanes, arylsilanes, aralkylsilanes, alkylalkoxysilanes, or alkylaminosilanes, as previously described herein.

[0073] In some embodiments of this disclosure, the silicon precursor may be pulsed into the reaction chamber for about 0.05 seconds to about 5.0 seconds, or about 0.1 seconds to about 3 seconds, or further about 0.2 seconds to about 1.0 seconds. In some embodiments, the silicon precursor may be pulsed into the reaction chamber for less than 0.1 seconds, or further less than 0.05 seconds. Furthermore, during contact between the substrate and the silicon precursor, the flow rate of the silicon precursor can be less than 1000 sccm, or less than 500 sccm, or less than 100 sccm, or less than 50 sccm, or further less than 5 sccm. Furthermore, during contact between the substrate and the silicon precursor, the flow rate of the silicon precursor can be in the range of about 5 to 50 sccm, or about 50 to 100 sccm, or about 100 to about 1000 sccm.

[0074] After sufficient time for the molecular layer to adsorb onto the substrate surface, excess silicon precursor may be removed from the reaction chamber. In some embodiments, if there is excess reactant and byproducts of the reactant, the excess silicon precursor may be purged by stopping the flow of the gas phase silicon precursor while continuing to flow a carrier gas, purge gas, or gas mixture for sufficient time to diffuse or purge them from the reaction chamber. In some embodiments, the excess silicon precursor may be purged with one or more inert gases, such as nitrogen, helium, or argon, which can flow through the entire periodic deposition phase 205 of the exemplary PEALD process 200.

[0075] In some embodiments, the silicon precursor may be purged from the reaction chamber for about 0.1 seconds to about 60 seconds, or about 0.3 seconds to about 30 seconds, or even further for about 0.3 seconds to about 10 seconds. The supply and removal of the silicon precursor can be considered the first or "silicon phase" of the exemplary PEALD process 200.

[0076] Once the purging of excess silicon precursor and all reaction byproducts from the reaction chamber is complete, the periodic deposition stage 205 of the exemplary PEALD process 200 can continue to a second phase by process block 230, which includes contacting the substrate with reactants generated from a plasma produced from a gas containing an oxygen precursor and a noble gas.

[0077] In some embodiments, the oxygen precursor may include at least one of molecular oxygen (O2), carbon dioxide (CO2), or nitrous oxide (N2O). In some embodiments, the noble gas may include at least one of argon, nitrogen, or helium. In some embodiments, the flow rate ratio of the noble gas to the oxygen precursor into the reaction chamber may be greater than 1, greater than 2, or even greater than 3. As described above, the plasma ("oxygen-based plasma") may be rich in ions, including at least oxygen ions, and may be generated using a parallel plate electrode configuration that can anisotropically accelerate multiple ions downward toward the substrate substantially vertically.

[0078] In some embodiments, an oxygen-based plasma can be generated by applying RF power of approximately 50W to 1000W, or approximately 100W to 500W, or approximately 100W to 300W. In some embodiments, the plasma may be generated in situ, while in other embodiments, the plasma may be generated remotely. In some embodiments, a showerhead reactor is utilized, and the plasma is generated between a lower electrode (i.e., a susceptor on which the substrate is placed) and an upper electrode (i.e., a showerhead plate).

[0079] In some embodiments, the reactive species generated from the plasma may be in contact with the substrate for about 0.1 seconds to about 12 seconds, or 0.5 seconds to about 5.0 seconds, or even 0.5 seconds to about 2.0 seconds. In some embodiments, the reactive species generated from the plasma may be in contact with the substrate for less than 1 second, or less than 0.5 seconds, or even less than 0.1 seconds.

[0080] After a sufficient period to completely saturate the previously adsorbed molecular layer and react with the oxygen-based plasma pulse, all excess reactants and reaction byproducts can be removed from the reaction chamber. Similar to the removal of gas-phase reactants, i.e., silicon precursors, this step may include stopping the generation of reactants and continuing to flow an inert gas. The inert gas flow may flow for a sufficient time to allow excess reactants and volatile reaction byproducts to diffuse and be purged from the reaction chamber. For example, the purging process may be utilized for approximately 0.1 seconds to 10 seconds, or approximately 0.1 seconds to 4.0 seconds, or even further for approximately 0.1 seconds to 0.5 seconds. Together, the supply and removal of the oxygen-based plasma constitute the second, reactant phase in the exemplary silicon nitride PEALD process 200 shown in Figure 2.

[0081] A method in which the substrate alternately contacts a gas-phase silicon precursor and reactants generated from a gas containing an oxygen precursor and a noble gas can constitute a unit deposition cycle. In some embodiments of the present disclosure, the exemplary PEALD process 200 may include repeating the unit deposition cycle one or more times. For example, the periodic deposition stage 205 of the exemplary PEALD process 200 may continue to a decision gate 240 that determines whether the PEALD process 200 continues or terminates. The decision gate 240 of the process block is determined based on the thickness of the deposited silicon oxide film, and if, for example, the thickness of the silicon oxide film is insufficient for the desired device structure, the PEALD process 200 may return to process block 220, and the process of contacting the substrate with the silicon precursor (process block 220) and then contacting the substrate with reactants (process block 230) may be repeated one or more times. Once the silicon oxide film is deposited to the desired thickness, the exemplary PEALD process 200 may terminate by process block 250, and the silicon oxide film may undergo additional processes to form a semiconductor device structure.

[0082] While the PEALD cycle is generally described herein as beginning with a silicon phase, in other embodiments, the cycle may begin with a reactive species phase. Those skilled in the art will recognize that the first precursor phase generally reacts with the terminations left by the last phase of the previous cycle. Thus, when the reactive species is the first phase of the PEALD cycle, the reactants are neither pre-adsorbed on the substrate surface nor present in the reaction chamber, but in subsequent cycles, the reactive species phase effectively follows the silicon phase. In some embodiments, one or more different PEALD cycles are provided in a deposition process.

[0083] Another overview of a non-limiting exemplary unit deposition cycle of the horizontally selective PEALD process of this disclosure is illustrated with reference to Figure 3. As illustrated in Figure 3, the horizontal axis represents time parameters, but not necessarily the actual time lengths of individual processes; the vertical axis represents the on or off states of gas flow and RF power, where a high level on the vertical axis for each parameter represents the on state, but the vertical axis for each line does not necessarily represent the actual amount of the relevant parameter; and the lowest level on each line of the vertical axis represents the off state, i.e., zero gas flow or no RF power supplied.

[0084] In short, during the first period 310 of the unit deposition cycle (i.e., the precursor pulse period), the silicon precursor may be pulsed into the reaction chamber along with the flow of the noble gas and oxygen precursors. During this first period 310, the silicon precursor can chemisorb onto the non-planar surface of the substrate to form a monolayer at most. During the second period 320 (i.e., the purge period), the flow of the silicon precursor is stopped, and the flow of the noble gas and oxygen precursors continues, purging excess silicon precursor and all reaction byproducts from the reaction chamber. During the third period 330 (i.e., the RF pulse period), the flow of oxygen precursor and noble gas continues into the reaction chamber, and pulses of RF power are supplied to the gas to excite the plasma and generate reactive species that react with the chemisorbed silicon precursor to form a silicon oxide film. During the fourth period 340 (i.e., the purge period), the RF power is off, and the flow of the noble gas and oxygen precursors continues, purging excess reactive species and all reaction byproducts from the reaction chamber.

[0085] Another non-limiting example of a periodic plasma-enhanced deposition process that can be used to form a silicon oxide film selectively in the horizontal direction is periodic plasma-enhanced chemical vapor deposition (periodic PECVD). Briefly, a non-planar substrate or workpiece is placed in a reaction chamber and can undergo one or more periodic PECVD deposition cycles.

[0086] An exemplary periodic PECVD process for forming a horizontally selective silicon oxide film is illustrated with reference to Figure 4. The exemplary periodic PECVD process 400 may include two phases. The first phase involves contacting the substrate with a first reaction species generated from a gas-phase reactant comprising silicon, carbon, and hydrogen components, and the second phase involves contacting the substrate with a second reaction species generated from a gas comprising an oxygen precursor and a noble gas.

[0087] Referring in more detail to Figure 4, an exemplary process 400 can be initiated by a process block 410 which includes supplying a substrate into a reaction chamber and heating the substrate to a suitable deposition temperature.

[0088] In some embodiments of this disclosure, the substrate may include materials and shapes previously disclosed herein, in particular, non-planar substrates having one or more horizontal surfaces and one or more vertical surfaces. Furthermore, the reaction chamber may include any of the reaction chambers (and associated apparatus) previously described herein, in particular a plasma-enhanced chemical vapor deposition (PECVD) reaction chamber and associated apparatus having a parallel plate electrode configuration for generating an anisotropic plasma.

[0089] In some embodiments of the present disclosure, the substrate placed in the reaction chamber may be heated to a desired deposition temperature for a subsequent periodic deposition stage 405 following an exemplary periodic PECVD process 400 (Figure 4). For example, the substrate may be heated to a substrate temperature of less than about 600°C, or less than about 550°C, or less than about 500°C, or less than about 450°C, or less than about 400°C, or less than about 350°C, or less than about 300°C, or even less than about 250°C. In some embodiments of the present disclosure, the substrate temperature during the exemplary periodic PECVD process 300 may be between about 150°C and about 600°C.

[0090] In addition to controlling the temperature of the substrate, the pressure within the reaction chamber can also be adjusted to allow the deposition of the desired silicon oxide film. In some embodiments, the occupancy density and the properties of the reactants generated in the plasma can also be controlled by adjusting the pressure within the reaction chamber. Thus, in some embodiments, the pressure within the reaction chamber during the exemplary periodic PECVD process 400 can be adjusted to a pressure greater than 150 Pascals, or greater than 300 Pascals, or greater than 450 Pascals, or greater than 600 Pascals, or even greater than 800 Pascals. For example, in some embodiments, the pressure within the reaction chamber during the exemplary periodic PECVD process 400 may be adjusted between 150 Pascals and 800 Pascals.

[0091] Once the substrate temperature is set to a desired deposition temperature and the pressure in the reaction chamber is adjusted as desired, the exemplary process 400 can be continued by a periodic deposition stage 405 which may include contacting the substrate with a first reaction species generated from the plasma and contacting the substrate with a second reaction species generated from the plasma.

[0092] More specifically, the periodic deposition stage 405 of the exemplary periodic PECVD process 400 may be continued by a process block 420 which includes contacting the substrate with a gas-phase reactant containing silicon components, carbon components, and hydrogen components, i.e., a first reactant generated from a silicon precursor.

[0093] In some embodiments, the first reactant may include multiple reactants generated from a gas-phase reactant comprising at least a silicon component, a carbon component, and a hydrogen component. For example, the gas-phase reactant may include, but is not limited to, all silicon precursors previously disclosed herein, and may include alkylsilanes, arylsilanes, aralkylsilanes, alkylalkoxysilanes, or alkylaminosilanes.

[0094] In some embodiments of this disclosure, the first reactant can be in contact with the non-planar substrate for about 0.05 seconds to about 5.0 seconds, or about 0.1 seconds to about 3 seconds, or further about 0.2 seconds to about 1.0 seconds. Furthermore, during the contact between the substrate and the first reactant, the flow rate of the gas-phase reactant can be less than 1000 sccm, or less than 500 sccm, or less than 100 sccm, or less than 50 sccm, or further less than 5 sccm.

[0095] The periodic deposition stage 405 of an exemplary periodic PECVD process 400 can be continued by a process block 430 which includes contacting the substrate with a second reaction species generated from a gas containing an oxygen precursor and a noble gas. In some embodiments, the oxygen precursor may include at least one of molecular oxygen (O2), carbon dioxide (CO2), or nitrous oxide (N2O), and the noble gas may include at least one of argon, nitrogen, or helium.

[0096] In some embodiments, the second reactive species can be generated from the plasma and can be in contact with the substrate for about 0.1 seconds to about 12 seconds, or 0.5 seconds to about 5.0 seconds, or even 0.5 seconds to about 2.0 seconds. In some embodiments, the second reactive species generated from the plasma may be in contact with the substrate for less than 1 second, less than 0.5 seconds, or even less than 0.1 seconds.

[0097] The manner in which the substrate comes into contact with a first reactant and then with a second reactant can constitute a unit deposition cycle. In some embodiments of the present disclosure, the exemplary periodic PECVD process 400 may include repeating the unit deposition cycle one or more times. For example, the periodic deposition stage 405 of the exemplary periodic PECVD process 400 may continue to a decision gate 440 that determines whether the periodic PECVD process 400 continues or terminates. The decision gate 440 of the process block is determined based on the thickness of the deposited silicon oxide film, and if, for example, the thickness of the silicon oxide film is insufficient for a desired device structure, the periodic PECVD process 400 may return to process block 420, and the process of bringing the substrate into contact with a first reactant (process block 420) and then bringing the substrate into contact with a second reactant (process block 430) may be repeated one or more times. Once the silicon oxide film is deposited to the desired thickness, the exemplary periodic PECVD process 400 may terminate by process block 450, and the silicon oxide film may undergo additional processes to form a semiconductor device structure.

[0098] The exemplary periodic PECVD process 400 in Figure 4 is illustrated as first contacting the substrate with a first reactant, and then contacting the substrate with a second reactant; however, naturally, any alternating sequence of contacting the substrate with a reactant can be utilized in the periodic PECVD process of this disclosure. For example, in some embodiments, both the first and second reactants may contact the substrate simultaneously within a unit deposition cycle. In another embodiment, in some embodiments, the second reactant may contact the substrate, and then subsequently the substrate may be contacted with the first reactant within a unit deposition cycle. In some embodiments, the substrate may be repeatedly contacted with the first reactant, and then subsequently the substrate may be contacted with the second reactant one or more times within a unit deposition cycle. Alternatively, the substrate may be repeatedly contacted with the second reactant, and then subsequently the substrate may be contacted with the first reactant one or more times within a unit deposition cycle. In some embodiments, the purge cycle may occur after contacting the substrate with the reactants, as described herein.

[0099] Another overview of a non-limiting, exemplary unit deposition cycle of the horizontally selective periodic PECVD process of this disclosure is illustrated with reference to Figure 5. As illustrated in Figure 5, and with reference to Figure 3, the horizontal axis represents the time parameter and the vertical axis represents the on-state or off-state.

[0100] In short, during the first period 510 of the unit deposition cycle (i.e., the deposition period), the noble gas and oxygen precursors can flow into the reaction chamber along with pulses of silicon precursors while RF power is continuously supplied. During the second period 520, the third period 530, and the fourth period 540 (i.e., the purge period), the silicon precursor flow can be turned off while the flow of noble gas and oxygen precursors is maintained along with the continuous supply of RF power.

[0101] Therefore, in some embodiments, a unit deposition cycle includes simultaneously bringing the substrate into contact with the first and second reactants, and purging any excess first and second reactants and all reaction byproducts. In such embodiments, the first and second reactants may be in contact with the non-planar substrate for less than 1 second, less than 0.5 seconds, or less than 0.1 seconds. In some embodiments, the short-duration contact between the non-planar substrate and the first and second reactants may result in shape-selective deposition of silicon oxide films on the upper horizontal surface of the non-planar substrate, for example, more material being deposited on the upper horizontal surface of the trench structure compared to the material deposited on the lower horizontal surface, i.e., the bottom and vertical surfaces of the trench structure, i.e., the side walls of the trench.

[0102] Another exemplary unit deposition cycle of the exemplary horizontally selective periodic PECVD process of this disclosure is illustrated with reference to Figure 6. As illustrated in Figure 6, and described with reference to Figure 3, the horizontal axis represents the time parameter and the vertical axis represents the on or off state.

[0103] In short, during the first period 610 of the unit deposition cycle (i.e., the deposition period), a noble gas can flow into the reaction chamber along with pulses of oxygen precursor. Furthermore, during the first period 610, a silicon precursor may be introduced into the reaction chamber by two or more discontinuous pulses, and RF power may be applied as discontinuous pulses. During the second period 620 of the unit deposition cycle (i.e., the purging period), the oxygen precursor flow, silicon precursor flow, and RF power may be turned off while the noble gas flow is maintained in the reaction chamber, thereby purging the reaction chamber. During the third period 630 of the unit deposition cycle (i.e., the processing period), the noble gas flow is increased, i.e., increased for a selected time, and discontinuous pulses of RF power can be applied to the noble gas to generate excited species of the noble gas. In some embodiments, excited species of the noble gas, such as argon ions or helium ions, can be used to remove excess silicon oxide film deposits located at the horizontal edges of a non-planar substrate. During the fourth period 640 (i.e., the purge period), the oxygen precursor flow, silicon precursor flow, and the noble gas flow can be reduced to their previous flow levels while the RF power is off.

[0104] Therefore, in some embodiments, a unit deposition cycle may include simultaneously contacting the substrate with a first and a second reactant, purging excess first and second reactants and all reaction byproducts, contacting the substrate with a third reactant generated from a noble gas, i.e., plasma excitation of the noble gas, and purging excess third reactants and all reaction byproducts from the reaction chamber. In such embodiments, the silicon oxide film can be selectively deposited on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate.

[0105] Another exemplary unit deposition cycle of the exemplary horizontally selective periodic PECVD process of this disclosure is illustrated with reference to Figure 7. As illustrated in Figure 7, and with reference to Figure 3, the horizontal axis represents the time parameter and the vertical axis represents the on or off state.

[0106] In short, during the first period 710 of a unit deposition cycle (i.e., the deposition period), a noble gas can be flowed into the reaction chamber along with two or more pulses of silicon precursor. Furthermore, discontinuous pulses of RF power can be applied to the gas during the first period 710. In such embodiments, a film containing silicon, carbon, and hydrogen may be deposited on the horizontal surface of the substrate by sputtering. During the second period 720 (i.e., the purging period), the noble gas flow may be maintained, while the silicon precursor flow and RF power may be turned off. During the third period 730 (i.e., the oxidation period), the noble gas flow may be maintained while oxygen precursor pulses are supplied to the reaction chamber along with discontinuous pulses of RF power. In some embodiments, the third period 730 can generate an oxygen-based plasma that can oxidize the previously sputtered film, thereby forming a silicon oxide film. During the fourth period 740 (i.e., the purging period), the noble gas flow may be maintained while the oxygen precursor flow, silicon precursor flow, and RF power are turned off.

[0107] Therefore, in some embodiments, a unit deposition cycle may include contacting the substrate with a first reactant, contacting the substrate with a fourth reactant generated from a gas containing a noble gas, purging all reactants and reaction byproducts from the reaction chamber, contacting the substrate with a second reactant, and purging all reactants and reaction byproducts from the reaction chamber. In such embodiments, the silicon oxide film can be selectively deposited on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate.

[0108] As a non-limiting example of embodiments of the present disclosure, Figures 8A and 8B illustrate schematic cross-sectional views of exemplary non-planar substrates before (Figure 8A) and after (Figure 8B) shape-selective silicon oxide formation, where the silicon oxide film is selectively formed on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate.

[0109] More specifically, Figure 8A illustrates a schematic cross-sectional view of a non-planar substrate 800. The non-planar substrate can include all the materials and shapes described herein, and in certain embodiments, the non-planar substrate 800 may include a silicone substrate. The non-planar substrate 800 may include several trench structures 802 ("vertical gap features") which may comprise one or more horizontal surfaces 804 and one or more vertical surfaces 806.

[0110] Figure 8B illustrates a schematic cross-sectional view of a non-planar substrate 800 after the formation of shape-selective silicon oxide on horizontal and vertical surfaces. As illustrated in Figure 8B, the silicon oxide film 808 may be deposited on the non-planar substrate 800 using either the PEALD process or the periodic PECVD process described above. In this particular example, the silicon oxide is formed by a horizontal-selective process, and therefore the silicon oxide film 808 may comprise a silicon oxide film 810 positioned on the horizontal surface of the non-planar substrate 800 having a greater thickness than the silicon oxide film 812 positioned on the vertical surface of the non-planar substrate 800.

[0111] As previously disclosed herein, the “selectivity” of a shape-selective process can be expressed as the ratio of the amount of material formed on a first plane of a non-planar substrate to the total amount of material formed on the first and second planes. In this example of a horizontal-plane selective process, the selectivity can be calculated as a percentage ratio of the thickness of the silicon oxide film placed on the horizontal plane compared to the sum of the thicknesses of the silicon oxide films placed on both the horizontal and vertical planes. Thus, in some embodiments of this disclosure, the shape selectivity for deposition on a horizontal plane of a non-planar substrate may be greater than 50%, or greater than 60%, or greater than 70%, or greater than 80%, or greater than 90%, or even equal to 100%, compared to deposition on a vertical plane of a non-planar substrate.

[0112] As another non-limiting example of embodiments of the present disclosure, Figures 9A–B illustrate scanning tunneling electron microscope (STEM) images of exemplary non-planar substrates after shape-selective formation of a silicon oxide film, where the silicon oxide film is selective for deposition on a horizontal plane over a vertical plane.

[0113] More specifically, the non-planar, shape-selective silicon oxide films shown in Figures 9A-B were deposited at a deposition temperature of approximately 250°C using the PEALD process, which utilizes hexamethyldisilane as the silicon precursor, molecular oxygen (O2) as the oxygen precursor, and argon as the noble gas.

[0114] Figure 9A illustrates a non-planar silicon substrate 900, a silicon oxide film 902 placed on the horizontal surface of the non-planar substrate, and a silicon oxide film 904 placed on the vertical surface of the non-planar substrate. In this non-limiting example, the PEALD process was repeated 500 times to obtain the silicon oxide film thickness illustrated in Figure 9A. The inspection in Figure 9A illustrates that the silicon oxide film 902 placed on the horizontal surface has a thickness of approximately 7 nanometers, the silicon oxide film 904 placed on the vertical surface has a thickness of approximately 3 nanometers, and that this is a horizontally selective process with 70% selectivity.

[0115] Figure 9B illustrates another non-planar silicon substrate 906, a silicon oxide film 908 placed on the horizontal surface of the non-planar substrate, and a silicon oxide film 910 placed on the vertical surface of the non-planar substrate. In this non-limiting example, the PEALD process was repeated 1000 times to obtain the silicon oxide film thickness illustrated in Figure 9B. The inspection in Figure 9B illustrates that the silicon oxide film 908 placed on the horizontal surface has a thickness of approximately 11 nanometers, the silicon oxide film 910 placed on the vertical surface has a thickness of approximately 3.5 nanometers, and that this is a horizontally selective process with 75% selectivity.

[0116] As another non-limiting example of embodiments of the present invention, Figure 10 shows the changes in both horizontal and vertical silicon oxide film thickness with increasing number of unit deposition cycles for an exemplary shape-selective PEALD. More specifically, the shape-selective PEALD process in this example is a horizontal-selective process, i.e., a thicker silicon oxide film is deposited on the horizontal plane compared to the thickness of the silicon oxide film deposited on the vertical plane. In this exemplary PEALD process, the silicon precursor is hexamethyldisilane, the oxygen precursor is molecular oxygen (O2), and the noble gas is argon, and the deposition temperature is approximately 250°C. Another examination of Figure 10 illustrates that the silicon oxide film placed on the horizontal plane is considerably thicker than the silicon oxide film placed on the vertical plane. For example, the silicon oxide film deposited after 500 deposition cycles has a thickness of approximately 7 nanometers horizontally and approximately 3 nanometers vertically, resulting in 70% selectivity. As another example, a silicon oxide film deposited after 1000 deposition cycles has a thickness of approximately 11 nanometers horizontally and 3.5 nanometers vertically, exhibiting 75% selectivity.

[0117] Vertical plane selective silicon oxide formation process In some embodiments of the present disclosure, a method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process may include selectively forming a silicon oxide film on a plane perpendicular to the horizontal plane of a non-planar substrate, i.e., a thicker thickness of silicon oxide material can be formed on the perpendicular plane of the non-planar substrate compared to the thickness of silicon oxide material that can be formed on the horizontal plane of the non-planar substrate.

[0118] In some embodiments of the present disclosure, a vertically selective silicon oxide formation process can be achieved using previously disclosed shape-selective deposition methods, along with selective etching of a silicon oxide film placed on a horizontal plane.

[0119] In some embodiments, a vertical plane-selective process can be achieved by forming a shape-selective silicon oxide film by periodic plasma-enhanced deposition, such as plasma-enhanced atomic layer deposition (PEALD) or periodic plasma-enhanced chemical vapor deposition (periodic PECVD). In some embodiments, periodic plasma-enhanced deposition may include periodic etching of the silicon oxide film placed on a horizontal surface of a non-planar substrate. In some embodiments, the silicon oxide film may be brought into contact with an etchant after deposition.

[0120] In some embodiments, selectively forming a silicon oxide film on the vertical surface of a non-planar substrate involves depositing a silicon oxide film with a higher carbon content on the vertical surface of the non-planar substrate compared to the carbon content of the silicon oxide film on the horizontal surface of the non-planar substrate, i.e., controlling the shape composition of the silicon oxide film deposition. In addition to utilizing an anisotropic oxygen-based plasma generated from a gas containing oxygen precursors and noble gases, the use of silicon precursors containing silicon components, carbon components, and hydrogen components can enable the control of the shape composition of the silicon oxide film deposition.

[0121] As a non-limiting example of shape composition control in silicon oxide film deposition, a unit deposition cycle in a periodic plasma-enhanced deposition process may include chemically adsorbing a silicon precursor onto a non-planar surface, forming up to a monolayer of the silicon precursor, and subsequently bringing the non-planar substrate into contact with an anisotropic plasma containing multiple ions accelerated substantially vertically downward toward the substrate. Because the ion incidence direction is substantially perpendicular to the horizontal plane of the non-planar substrate, more ions irradiate or collide with the horizontal plane of the non-planar substrate relative to the vertical plane. Therefore, the reaction between the adsorbed silicon species and ions is greater on the horizontal plane than on the vertical plane, thereby preventing complete alteration of the film deposited on the vertical plane, and consequently retaining a considerable carbon content in the silicon oxide film positioned on the vertical plane.

[0122] Therefore, in some embodiments, a shape-selective deposition process can deposit silicon oxide films on the vertical surfaces of a non-planar substrate that contain a higher carbon content than silicon oxide films on the horizontal surfaces of the non-planar substrate. For example, the silicon oxide film placed on the vertical surface may contain silicon oxycarbide or carbon-doped silicon oxide. The etching rate of the deposited silicon oxide film may vary depending on the carbon concentration in the deposited silicon oxide film. For example, in some embodiments, the silicon oxide film on the vertical surfaces of a non-planar substrate may have a lower etching rate than the silicon oxide film on the horizontal surfaces of the non-planar substrate.

[0123] By utilizing the difference in etching rates of deposited silicon oxide films through shape composition control, silicon oxide films positioned on horizontal planes can be selectively removed from silicon oxide films positioned on vertical planes. In some embodiments, silicon oxide films positioned on horizontal planes can be selectively removed during a periodic plasma-enhanced deposition process by adding another process step that may include contacting a non-planar substrate with other reactive species generated from a plasma produced from a gas containing hydrogen and noble gases. In some embodiments, silicon oxide films positioned on horizontal planes can be selectively removed by contacting the substrate with an etchant after deposition, allowing for selective removal of silicon oxide films on the horizontal plane of a non-planar substrate compared to silicon oxide films on the vertical plane of the non-planar substrate. In some embodiments, selective removal of silicon oxide on horizontal planes during a periodic deposition cycle may be combined with contacting the substrate with an etchant after deposition.

[0124] An exemplary periodic plasma-enhanced deposition process may include a PEALD process that includes one or more periodic etching steps for selectively removing a silicon oxide film positioned on a horizontal surface of a non-planar substrate, thereby providing a vertical plane-selective process.

[0125] More specifically, Figure 11 illustrates an exemplary PEALD process 1100 that includes a periodic etching step for selectively removing a silicon oxide film on a horizontal surface of a non-planar substrate. The exemplary PEALD process 1100 can be initiated by process block 1110, which includes supplying the non-planar substrate into a reaction chamber and heating the substrate to a suitable deposition temperature. Process block 1100 may be identical to process block 210 (Figure 2), and therefore, for brevity, the details of this process will not be repeated.

[0126] The exemplary PEALD process 1100 may be continued by a periodic deposition etching stage 1105. In some embodiments, the periodic deposition etching 1105 may be initiated using a process block 1120 which includes contacting the substrate with a gas-phase reactant containing silicon, carbon, and hydrogen components. Process block 1120 may be identical to process block 220 (Figure 2), and therefore for brevity, the details of this process will not be repeated. The periodic deposition etching stage 1105 may be continued by a process block 1130 which includes contacting the substrate with reactants generated from a plasma produced from a gas containing an oxygen precursor and a noble gas. Process block 1130 may be identical to process block 230 (Figure 2), and therefore for brevity, the details of this process will not be repeated. Process blocks 1120 and 1130 may collectively be referred to as the “periodic deposition process” in the exemplary PEALD process 1100.

[0127] The periodic deposition etching stage 1105 may be followed by a process block 1140 which includes contacting the substrate with another reactant generated from a plasma produced from a gas containing hydrogen and noble gases. Process block 1140 may be referred to as the “periodic etching step” in the exemplary PEALD process 1100. In some embodiments, the other reactant selectively removes the silicon oxide film on the horizontal surface of the non-planar substrate compared to the silicon oxide film on the vertical surface of the non-planar substrate.

[0128] In some embodiments of the present disclosure, the gas used to generate the plasma for the periodic etching process (process block 1140) may include hydrogen gas and a noble gas. In some embodiments, the noble gas may include at least one of argon, nitrogen, or helium. In some embodiments, the flow rate ratio of the noble gas to the hydrogen gas into the reaction chamber may be greater than 2, greater than 3, or even greater than 4.

[0129] In some embodiments, other reactive species used to selectively etch the silicon oxide film can be generated by applying RF power to a gas containing hydrogen gas and noble gases. For example, the RF power applied to the gas can be less than 500W, or less than 300W, less than 100W, or 500W to 50W.

[0130] In some embodiments, other reactive species can be generated from an anisotropic plasma by using a parallel plate electrode configuration, and the anisotropic plasma may contain a plurality of ions that are accelerated substantially vertically downward toward the substrate. Due to the anisotropic nature of the plasma, the ion collision rate may be higher on the horizontal surface of a non-planar substrate compared to the vertical surface of the non-planar substrate, and as a result, the silicon oxide film is selectively etched on the horizontal surface of the substrate compared to the vertical surface of the substrate.

[0131] In some embodiments of the present disclosure, another reactant may be in contact with the non-planar substrate for less than 5 seconds, less than 3 seconds, or even less than 1 second. In some embodiments, another reactant may be in contact with the non-planar substrate for 0.05 seconds to 1 second.

[0132] After the periodic etching step (process block 1140), the reaction chamber can be purged to remove any excess reactants and all by-products. In some embodiments, the reaction chamber may be purged for about 0.1 seconds to about 10 seconds, or about 0.3 seconds to about 5 seconds, or even further for about 0.3 seconds to about 1 second.

[0133] As a non-limiting example, Figure 12 illustrates ellipsometric data showing the etched thickness (nanometers) of a silicon oxide film against plasma exposure time (seconds). For example, the noble gas may include argon, the reaction chamber pressure may be approximately 350 Pascals, the substrate temperature may be approximately 450°C, and the RF power may be approximately 100 W. The inspection in Figure 12 illustrates the case where a silicon oxide film of approximately 0.4 nanometers is etched with a plasma exposure time of 30 seconds (etching rate 0.8 nanometers / minute), and the case where a silicon oxide film of approximately 0.7 nanometers is etched with a plasma exposure time of 60 seconds (etching rate 0.7 nanometers / minute).

[0134] The periodic deposition etching stage 1105 of the exemplary PEALD process 1100 (Figure 11) may pass a decision gate 1150 that determines whether the PEALD process 1100 continues or terminates. The decision gate 1150 of the process block is determined based on the thickness of the silicon oxide film formed on the non-planar substrate. For example, if the thickness of the silicon oxide film is insufficient for the desired device structure, the PEALD process 1100 may return to process block 1120, where the non-planar substrate is brought into contact with a silicon precursor (process block 1120), the non-planar substrate is brought into contact with a reactant (process block 1130), the substrate is brought into contact with a reactant generated from hydrogen gas (process block 1140), and the unit cycle may be repeated once or more times.

[0135] Naturally, the sequence of contacting the substrate with the silicon precursor (process block 1120), the reactant (process 1130), and another reactant (process block 1140) can be performed in all possible order. Furthermore, one or more process blocks may be repeated once or more times before subsequent process blocks are executed. Once the silicon oxide film is formed to the desired thickness, the exemplary PEALD process 1100 may be terminated by process block 1160, and the silicon oxide film may undergo additional processes to form a semiconductor device structure.

[0136] Another overview of a non-limiting exemplary unit deposition cycle of the vertically selective periodic PEALD process of this disclosure is illustrated with reference to Figure 13. As illustrated in Figure 13, and with reference to Figure 3, the horizontal axis represents the time parameter and the vertical axis represents the on or off state.

[0137] In short, during the first period 1310 (i.e., the silicon precursor pulse period), the noble gas and oxygen precursor can flow into the reaction chamber along with the silicon precursor pulse, and the silicon precursor can be chemisorbed onto the surface of a non-planar substrate. During the second period 1320 (i.e., the purge period), the flow of the noble gas and oxygen precursor can be maintained to purge the reaction chamber while the remaining parameters are in the off state. During the third period 1330 (i.e., the RF power period), the flow of the noble gas and oxygen precursor can be maintained, and a pulse of RF power can be applied to the gas to form a plasma containing at least oxygen ions that can react with the chemisorbed silicon to form a silicon oxide film. During the fourth period 1340 (i.e., the purge period), all parameters may be in the off state, and the reaction chamber may be purged by pumping all reactants and byproducts into a vacuum pump. During the fifth period 1350 (i.e., the etching period), pulses of hydrogen gas and noble gas are supplied to the reaction chamber, and RF power pulses are applied to the gas to form an anisotropic plasma that selectively etches the silicon oxide film on the horizontal plane. During the sixth period 1360 (i.e., the purging period), all parameters can be turned off, and the reaction chamber can be purged by pumping all reactants and byproducts into a vacuum pump. In some embodiments, the noble gas flow can be maintained during periods 1340 and 1360 to assist in purging the reaction chamber.

[0138] Another non-limiting example of a vertical plane selective silicon oxide formation process involves the shape deposition of a silicon oxide film, followed by contact of the silicon oxide film with an etchant to selectively remove the silicon oxide film on the horizontal plane relative to the silicon oxide film on the vertical plane.

[0139] More specifically, Figure 14 illustrates an exemplary vertically selective process 1400 which can be initiated by process block 1410, which includes supplying a substrate into a reaction chamber and heating the substrate to a suitable deposition temperature. Process block 1410 may be identical to process block 210 (Figure 2) or process block 410 (Figure 4), and therefore for brevity, the details of this process will not be repeated. The exemplary vertically selective process 1400 can be continued by a periodic plasma-enhanced deposition process which may include a periodic deposition stage 205 (of the exemplary PEALD process in Figure 2), a periodic deposition stage 405 (of the exemplary periodic PECVD process in Figure 4), or a periodic deposition etching stage 1105 (of the exemplary PEALD process 1100 in Figure 11), all of which have been previously described in detail and therefore will not be repeated for brevity.

[0140] The periodic plasma-enhanced deposition method used to deposit the silicon oxide film described in the embodiments of this disclosure may further include shape composition control of the silicon oxide film, as described herein. Therefore, in some embodiments, the carbon content of the silicon oxide film positioned on a vertical plane may be greater than that of the silicon oxide film positioned on a horizontal plane. Such a difference in carbon content results in a difference in etching rates between the silicon oxide films positioned on vertical and horizontal planes, i.e., the etching rate of the silicon oxide film is lower on the vertical plane, and this difference in etching rates can be used to selectively remove the silicon oxide film positioned on the horizontal plane of a non-planar substrate.

[0141] Therefore, the exemplary vertically selective silicon oxide formation process 1400 can be continued by a process block 1420 which includes contacting the silicon oxide film with an etchant to selectively remove the silicon oxide film located on the horizontal surface of the non-planar substrate with respect to the silicon oxide film located on the vertical surface of the non-planar substrate. In some embodiments, selective etching of the silicon oxide film can completely remove the silicon oxide film located on the horizontal surface of the non-planar substrate while maintaining the thickness of the silicon oxide film located on the vertical surface of the non-planar substrate.

[0142] In some embodiments of this disclosure, the etchant may include a wet chemical etchant or a plasma-based etchant. In some embodiments, the wet chemical etchant may include hydrofluoric acid (HF), for example, diluted hydrofluoric acid (1:100). In some embodiments, the plasma-based etchant may include anisotropic plasma etching using a fluorine-based chemical (e.g., CF4, SF6), a chlorine-based chemical (e.g., Cl2, BCl3), or a hydrogen gas-based plasma etchant previously described herein.

[0143] In some embodiments of the present disclosure, the ratio of the etching rate of a silicon oxide film deposited on a vertical surface to the etching rate of a silicon oxide film placed on a horizontal surface can be greater than 2, or greater than 3, or greater than 5, or even greater than 10. As a non-limiting example, a silicon oxide film deposited according to embodiments of the present disclosure may have an etching rate of more than 200% on the horizontal surface of a non-planar substrate compared to a silicon oxide film on the vertical surface of the non-planar substrate, i.e., a wet etching rate ratio (WERR) between horizontal and vertical silicon oxide is greater than 2.

[0144] As non-limiting examples of embodiments of the present disclosure, Figures 15A and 15B illustrate an exemplary non-planar substrate (Figure 15A) after shape-selective deposition of a silicon oxide film by shape control of a silicon oxide composition, and an exemplary non-planar substrate (Figure 15B) obtained by selectively removing silicon oxide films positioned on a horizontal plane from silicon oxide films positioned on a vertical plane by contacting the silicon oxide film with an etchant.

[0145] More specifically, Figure 15A illustrates a non-planar substrate 1500 and a silicon oxide film 1510 deposited by an embodiment of the present disclosure, disposed on the non-planar surface of the substrate 1500. The silicon oxide film includes a thicker silicon oxide film disposed on a horizontal plane 1520 and a thinner silicon oxide film disposed on a vertical plane 1530. Furthermore, the silicon oxide film disposed on the vertical plane 1530 may have a higher carbon concentration compared to the silicon oxide film disposed on the horizontal plane 1520, and therefore the vertical silicon oxide film 1530 may have a lower etching rate than the horizontal silicon oxide film 1520.

[0146] Figure 15B illustrates a silicon oxide film after contact with an etchant, such as a wet chemical etchant or an anisotropic plasma etchant. As shown in Figure 15B, the silicon oxide film 1530 positioned on a vertical surface maintains substantial thickness, while the silicon oxide film positioned on the horizontal surface of the non-planar substrate 1500 is selectively removed, thereby resulting in vertical-plane selective silicon oxide formation.

[0147] As previously disclosed herein, the “selectivity” of a shape-selective process can be expressed as the ratio of the amount of material formed on a first plane of a non-planar substrate to the total amount of material formed on the first and second planes. In this example of a vertical-plane selective process, the selectivity can be calculated as a percentage ratio of the thickness of the silicon oxide film placed on the vertical plane compared to the total thickness of the silicon oxide film placed on both the horizontal and vertical planes. Thus, in some embodiments of this disclosure, the shape selectivity for the formation of a silicon oxide film placed on the vertical plane of a non-planar substrate may be greater than 50%, or greater than 60%, or greater than 70%, or greater than 80%, or greater than 90%, or even equal to 100%, compared to the formation of a silicon oxide film placed on the horizontal plane of a non-planar substrate.

[0148] The exemplary embodiments of this disclosure described above are merely examples of embodiments of the invention as defined by the appended claims and their legal equivalents, and therefore do not limit the scope of the invention by these embodiments. Any equivalent embodiments are intended to fall within the scope of the invention. In fact, various modifications of this disclosure, in addition to those shown and described herein, such as useful alternative combinations of the elements described, may be apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims. [Explanation of Symbols]

[0149] 100 PEALD devices 101 Base material 102 Lower Stage 103 Reaction Chamber 104 Upper electrode 105 Conveyor Chamber 106, 107 Exhaust lines 111 Inside the reaction chamber 112 The other side of the reaction chamber 113 Circular duct 114 Separation Plate 120RF power 121, 122, 123 Gas lines 124 Seal Gas Line 200 PEALD processes 205 Periodic Sedimentation Stages 300 Periodic PECVD Process 310, 510, 610, 710: The first period of each unit sediment cycle. The second period of the 320, 520, 620, and 720 unit sediment cycles. The third period of the 330, 530, 630, and 730 unit sediment cycles. The fourth period of the 340, 540, 640, and 740 unit sediment cycles. 400 Periodic PECVD Process 405 Periodic Sedimentation Stages 800 Non-planar substrate 802 Trench structure 804 Horizontal plane 806 Vertical plane 808 Silicon oxide film 810 Silicon oxide film placed on a horizontal surface 812 Silicon oxide film placed on a vertical surface 900 Non-planar silicon substrate 902 Silicon oxide film placed on a horizontal surface 904 Silicon oxide film placed on a vertical surface 906 Non-planar silicon substrate 908 Silicon oxide film placed on a horizontal plane 910 Silicon oxide film placed on a vertical surface 1100 PEALD process 1105 Periodic deposition etching 1310 First period 1320 Second period 1330 Third Period 1340 The Fourth Period 1350 The Fifth Period 1360 The Sixth Period 1400 Vertically selective processes 1500 Non-planar substrate 1510 Silicon oxide film 1520 horizontal plane 1530 Vertical plane

Claims

1. A method for forming a shape-selective silicon oxide film by a periodic plasma-enhanced deposition process, wherein the method comprises: A non-planar substrate having one or more horizontal surfaces and one or more vertical surfaces is supplied into the reaction chamber. The non-planar substrate is brought into contact with a first reactant generated from a first gas containing at least a gas-phase reactant including a silicon component, a carbon component, and a hydrogen component, while discontinuous pulses of RF power are applied, wherein the first gas is supplied as two or more pulses. The non-planar substrate is brought into contact with a second reactant generated from a second gas that contains at least an oxygen precursor and an inert gas, and does not contain a fluorine component. A method comprising selectively forming a silicon oxide film on the horizontal surface of the non-planar substrate.

2. The method according to claim 1, wherein the gas-phase reactant comprises at least one of alkylsilane, arylsilane, or aralkylsilane.

3. The method according to claim 1, wherein the gas-phase reactant further comprises at least one of a nitrogen component or an oxygen component.

4. The method according to claim 3, wherein the gas-phase reactant comprises at least one of alkylalkoxysilane or alkylaminosilane.

5. The method according to claim 1, wherein the periodic plasma-enhanced deposition process comprises a periodic plasma-enhanced chemical vapor deposition process.

6. The periodic plasma-enhanced chemical vapor deposition process comprises one or more repetitions of a unit deposition cycle, the unit deposition cycle being: The non-planar substrate is brought into contact with the first reactant and the second reactant simultaneously, The method according to claim 5, comprising purging excess first reactants and excess second reactants, as well as all reaction by-products.

7. The method according to claim 6, wherein the first reactant and the second reactant are in contact with the non-planar substrate for less than one second.

8. The method according to claim 6, wherein the silicon oxide film is formed shape-selectively on the upper horizontal surface of the non-planar substrate.

9. The periodic plasma-enhanced chemical vapor deposition process comprises one or more repetitions of a unit deposition cycle, the unit deposition cycle is The non-planar substrate is brought into contact with the first reactant and the second reactant simultaneously, Purging excess first and second reactants, as well as all reaction by-products, The non-planar substrate is brought into contact with a third reactant generated from an inert gas, The method according to claim 5, comprising purging an excess third reactant and all reaction by-products.

10. The method according to claim 9, wherein the silicon oxide film is selectively deposited on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate.

11. The method according to claim 10, wherein the shape selectivity is greater than 50% when the non-planar substrate is deposited on the horizontal surface compared to when the non-planar substrate is deposited on the vertical surface.

12. The periodic plasma-enhanced chemical vapor deposition process comprises one or more repetitions of a unit deposition cycle, the unit deposition cycle being: The non-planar substrate is brought into contact with the first reactant, The non-planar substrate is brought into contact with a fourth reactant generated from a gas containing an inert gas, Purge all reactants and reaction by-products. The non-planar substrate is brought into contact with the second reactant, The method according to claim 5, comprising purging all reactants and reaction by-products.

13. The method according to claim 12, wherein the silicon oxide film is selectively deposited on the horizontal surface of the non-planar substrate relative to the vertical surface of the non-planar substrate.

14. The method according to claim 13, wherein the shape selectivity is greater than 50% when the non-planar substrate is deposited on the horizontal surface compared to when the non-planar substrate is deposited on the vertical surface.

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