TW201822259A - Remote plasma based deposition of oxygen doped silicon carbide films - Google Patents

Abstract

Disclosed are methods and systems for providing oxygen doped silicon carbide. A layer of oxygen doped silicon carbide can be provided under process conditions that employ one or more silicon-containing precursors that have one or more silicon-hydrogen bonds and/or silicon-silicon bonds. The silicon-containing precursors may also have one or more silicon-oxygen bonds and/or silicon-carbon bonds. One or more radical species in a substantially low energy state can react with the silicon-containing precursors to form the oxygen doped silicon carbide film. The one or more radical species can be formed in a remote plasma source.

Description

Remote plasma-based deposition of oxygen-doped silicon carbide films

This disclosure relates generally to the formation of oxygen-doped silicon carbide films.

Silicon carbide (SiC) -based films have unique physical, chemical, and mechanical properties and are used in different applications, especially integrated circuit applications. One such SiC-based film includes oxygen-doped SiC.

This disclosure relates to a method for depositing an oxygen-doped silicon carbide (SiCO) film. The method includes providing a substrate and flowing one or more silicon-containing precursors onto the substrate, each of the one or more silicon-containing precursors having (i) one or more silicon-hydrogen bonds and / or silicon-silicon bonds, With (ii) one or more silicon-oxygen bonds and one or more silicon-carbon bonds. The method further includes flowing a source gas to a remote plasma source, generating a radical of hydrogen from the source gas in the remote plasma source, and introducing the hydrogen radical to a substrate, wherein at least 90% of the radicals are in a substantial state. The free radical of the hydrogen in the low energy state is in a substantially low energy state under the condition of breaking one or both of the silicon-hydrogen bond and the silicon-silicon bond but retaining the silicon-oxygen bond and the silicon-carbon bond. The free radicals react with one or more silicon-containing precursors to form a SiCO film on the substrate.

In some embodiments, the silicon-containing precursor includes a cyclic siloxane. In some embodiments, the silicon-containing precursor includes an alkoxysilane. In some embodiments, the free radicals are generated from a source gas of hydrogen. In some embodiments, the ratio of silicon-oxygen bonds to silicon-carbon bonds in the SiCO film is between about 0.5: 1 and 3: 1. In some embodiments, the SiCO film includes a conformal film on a substrate. In some embodiments, the substrate includes a transistor having a gate electrode, and the method further includes forming a SiCO film on one or more sidewalls of the gate electrode.

This disclosure is also related to equipment for depositing an oxygen-doped silicon carbide film on a substrate. The device includes a reaction chamber including a substrate support for supporting a substrate, a remote plasma source coupled to the reaction chamber and a plasma source configured to generate a plasma outside the reaction chamber, and one or more coupled to the reaction chamber. More gas inlets and a controller, the controller including instructions to: (a) cause one or more silicon-containing precursors to flow to the substrate, each of the one or more silicon-containing precursors Has (i) one or more silicon-hydrogen bonds and / or silicon-silicon bonds, and (ii) one or more silicon-oxygen bonds and one or more silicon-carbon bonds, and (b) causes the source gas to flow to In a remote plasma source, (c) generates hydrogen radicals from the source gas in the remote plasma source, and (d) introduces hydrogen radicals onto the substrate, where at least 90% of the radicals are at a substantially low energy Free radicals of the hydrogen state, which are in a substantially low energy state under the condition of breaking one or both of the silicon-hydrogen bond and the silicon-silicon bond but retaining the silicon-oxygen bond and the silicon-carbon bond. Reacts with one or more silicon-containing precursors to form a SiCO film on a substrate.

In some embodiments, the silicon-containing precursor includes a cyclic siloxane. In some embodiments, the silicon-containing precursor includes an alkoxysilane. In some embodiments, the free radicals are generated from a source gas of hydrogen. In some embodiments, the ratio of silicon-oxygen bonds to silicon-carbon bonds in the SiCO film is between about 0.5: 1 and 3: 1. In some embodiments, the SiCO film includes a conformal film on a substrate. In some embodiments, the substrate includes a transistor having a gate electrode, and the controller further includes an instruction to form a SiCO film on one or more sidewalls of the gate electrode.

In the following description, numerous specific details are set forth to provide a thorough understanding of the concepts presented. The concepts presented may be practiced without some or all of these specific details. In other cases, well-known process operations are not described in detail to avoid unnecessarily obscuring the concept of description. Although some concepts will be described in conjunction with specific embodiments, it will be understood that these embodiments are not intended to be limiting.

In this application, the terms "semiconductor wafer", "wafer", "substrate", "wafer substrate" and "partially manufactured integrated circuit" are used interchangeably. Those of ordinary skill in the art will understand that the term "partially manufactured integrated circuit" may refer to a silicon wafer at any stage of the many stages of integrated circuit manufacturing on a silicon wafer. The wafer or substrate used in the semiconductor element industry typically has a diameter of 200 mm, or 300 mm, or 450 mm. The following embodiments assume that the present invention is implemented on a wafer. However, the invention is not so limited. The workpiece can have various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that can utilize the present invention include various objects, such as printed circuit boards, magnetic recording media, magnetic recording sensors, mirrors, optical elements, micromechanical elements, and the like. introduction

The manufacture of semiconductor devices typically involves depositing one or more thin films on a substrate during a integrated circuit manufacturing process. In some embodiments of the manufacturing process, thin films such as SiC and SiCN use atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), or any other Deposited by a suitable deposition method.

Another type of thin film that can be deposited includes silicon oxycarbide (SiOC). Conventional SiOC films are typically formed by using carbon-doped silicon oxide. The silicon-containing precursor may be transported with a carbon-containing precursor such as methane, carbon dioxide, or carbon monoxide. A carbon-containing silicon oxide film can be formed using a suitable deposition process. In some embodiments, the precursor molecules used to deposit SiOC include silicon-hydrogen (Si-H) bonds, silicon-silicon (Si-Si) bonds, silicon-carbon (Si-C) bonds, and / or silicon- Silicon-containing molecules with oxygen (Si-O) bonds. Today's PECVD processes can utilize in-situ plasma processing, where the plasma is provided directly adjacent to the substrate being processed.

It has been found that depositing high-quality SiOC films may have certain challenges, such as providing excellent step coverage, low dielectric constant, high breakdown voltage, low leakage current, high porosity, and / or without oxidizing the metal surface The coverage of exposed metal surfaces.

Although this disclosure is not limited to any particular theory, it is believed that the plasma conditions in a typical PECVD process cause silicon-containing precursor molecules to break in a manner that produces undesirable results. For example, PECVD may break the Si-O and / or Si-C bonds in the precursor molecules, resulting in highly reactive free radicals or other segmentation types with high adhesion coefficients. The segment, and the resulting SiOC film may include silicon, carbon, and / or oxygen atoms having "dangling bonds", meaning that the silicon, carbon, and / or oxygen atoms are reactive unpaired valence electrons. Precursor molecules with high adhesion coefficients and their fragments may deposit SiOC films with poor step coverage, as reactive precursor fragments may disproportionately adhere to the sidewalls in recessed features and upper areas of other structures. Dangling bonds can generate silanol groups (Si-OH) in the deposited SiOC film. As a result, the film may have a disadvantageously high dielectric constant. Film quality may also be impaired due to the tendency of direct plasma conditions to extract carbon from the deposited film.

Furthermore, dangling bonds can generate increased silicon-hydrogen bonds (Si-H) in the deposited SiOC film. Under direct plasma deposition conditions, the broken Si-C bond can be replaced by Si-H. The presence of Si-H bonds in the SiOC film can produce a film with poor electrical properties. For example, because Si-H bonds provide a leaky path for electrons, the presence of Si-H bonds may reduce the breakdown voltage and may increase the leakage current.

Further, dangling bonds can lead to uncontrolled chemical or morphological structures in the SiOC film. In some cases, the structure is a dense fine line with low porosity or no porosity, such that the film has an unacceptably high dielectric constant. The lack of porosity can be the result of direct plasma conditions that break the Si-C and / or Si-O bonds in the cyclic siloxane, otherwise the Si-C and / or Si-O bonds provide very low k Porosity in dielectric materials.

Because the energy that breaks the precursor molecules can be a low frequency that produces many ion bombardments at the surface, the direct plasma conditions sometimes used in PECVD can cause directivity in deposition. Directional deposition can also result in the deposition of SiOC films with poor step coverage. Direct plasma is a plasma in which the plasma (electrons and positive ions at appropriate concentrations) resides in the vicinity of the substrate surface during the deposition, sometimes separated only by the plasma sheath from the substrate surface.

Typical PECVD processes are sometimes unsuitable for depositing SiOC films on exposed copper or other metal surfaces because such processes can oxidize metals. PECVD processes can use oxidants such as oxygen (O ₂ ), ozone (O ₃ ), carbon dioxide (CO ₂ ), carbon monoxide (CO) or other oxide species to form SiOC. Environment at substrate surface during deposition

FIG. 1A illustrates a cross-section of an example of an oxygen-doped silicon carbide film deposited on a substrate. The oxygen-doped silicon carbide film 101 may be formed under process conditions that generate a relatively moderate environment near the substrate 100. The substrate 100 may be any wafer, a semiconductor wafer, a partially fabricated integrated circuit, a printed circuit board, a display screen, or other suitable workpieces. The process for depositing the oxygen-doped silicon carbide film 101 may include one or more silicon-containing precursors having one or more Si-H bonds and / or one or more Si-Si bonds.

Some applications using oxygen-doped silicon carbide films are depicted in Figures 1B-1D. In some embodiments, the silicon-containing precursor may include a silicon-oxygen-containing precursor and / or a silicon-carbon-containing precursor. The silicon-oxygen-containing precursor may include one or more Si-O bonds and the silicon-carbon-containing precursor may include one or more Si-C bonds. For example, in some embodiments, the silicon-containing precursor may include a single reactant A having a Si-O bond and a Si-C bond. In some embodiments, the silicon-containing precursor may include a reactant B having Si-O and a reactant C having a Si-C bond. It will be understood that any number of suitable reactants may be used in the context of this disclosure. The chemical structure of an exemplary silicon-containing precursor is discussed in further detail below.

The silicon-containing precursor includes one or more Si-H bonds and / or one or more Si-Si bonds. During the deposition process, the Si-H bond and / or the Si-Si bond will be broken and act as a reaction site for forming a bond between the silicon-containing precursors in the deposited oxygen-doped silicon carbide film 101. Broken bonds can also serve as sites for cross-linking during heat treatment (during or after deposition). The bonds at the reaction sites or at the crosslinks can collectively form the main backbone or matrix in the generated oxygen-doped silicon carbide film 101.

In some embodiments, the process conditions may retain or at least substantially retain Si-O bonds and Si-C bonds in the oxygen-doped silicon carbide film 101 layer thus deposited. Accordingly, the reaction conditions near the substrate 100 provide Si-H bond and / or Si-Si bond disconnection, for example, hydrogen is extracted from the broken Si-H bond, but reaction conditions do not provide extraction from the Si-O bond Oxygen or carbon can be removed from the Si-C bond. Generally, the described reaction conditions exist at the exposed surface of the substrate (the surface on which the oxygen-doped silicon carbide film is deposited). The reaction conditions exist more at several distances above the workpiece, such as about 0.5 microns to about 150 mm above the workpiece. In fact, activation of the precursor can occur in a gas phase at a substantial distance above the workpiece. Typically, the relevant reaction conditions will be uniform or substantially uniform across the entire exposed surface of the substrate, however certain applications may allow some variation.

In addition to silicon-containing precursors, the environment near the workpiece may include one or more free radical species, which are preferably in a substantially low energy state. Examples of such species include hydrogen atom radicals. In some embodiments, all, or substantially all, or substantially a portion of the hydrogen atom radicals may be in a ground state, such as at least about 90% or 95% of the hydrogen atom radicals in the vicinity of the workpiece are in a ground state. In certain embodiments, hydrogen is provided in a carrier such as helium. As an example, hydrogen may be provided in a helium carrier at a concentration of about 1-10% hydrogen. The pressure, the amount of carrier gas such as helium, and other process conditions are chosen so that hydrogen atoms, as free radicals in low energy states, collide with the substrate and no longer combine.

As explained elsewhere, hydrogen can be supplied to a remote plasma source to generate hydrogen radicals. Once generated, hydrogen radicals can be in an excited energy state. For example, hydrogen in an excited energy state may have an energy (first excited state) of at least 10.2 eV. Excited hydrogen radicals may cause non-selective decomposition of silicon-containing precursors. For example, hydrogen radicals in an excited state can easily break Si-H bonds, Si-Si bonds, Si-O bonds, and Si-C bonds, which can change the composition, or physical or electrical properties, of silicon carbide films. In some embodiments, when an excited hydrogen radical loses its energy or relax, the excited hydrogen radical can become a substantially low energy state hydrogen radical or a ground state hydrogen radical. A hydrogen radical in a substantially low energy state or a ground state may have the ability to selectively break Si-H bonds and Si-Si bonds while substantially retaining Si-O bonds and Si-C bonds. In some embodiments, the process conditions may be set such that the excited hydrogen radicals lose energy or relax to form a substantially low energy state or ground state hydrogen radical. For example, the remote plasma source or related elements can be designed such that the residence time of the hydrogen radicals from the remote plasma source to the substrate is greater than the energy relaxation time of the excited hydrogen radicals. The energy relaxation time of the excited hydrogen radical may be approximately equal to or less than 1 × 10 ^-3 seconds.

A substantial amount of hydrogen atom radicals in a ground state can be achieved by different techniques. For example, as described below, some devices are designed to achieve this state. Equipment characteristics and process control characteristics can be tested and adjusted to generate a substantial amount of hydrogen atom radicals in a moderate state in the ground state. For example, equipment can be operated and tested for charged particles downstream of the plasma source (ie, near the substrate). Processes and equipment can be adjusted until virtually no charged species exist near the substrate. In addition, the equipment and process characteristics can be adjusted to the configuration where it begins to produce high-quality silicon carbide films from standard precursors (such as trimethylsilane). The relatively modest conditions that support such film deposition are those who choose.

Other examples of radical species include nitrogen-containing species such as elemental nitrogen radicals (atomic, or diatomic) and N-H-containing radicals such as ammonia radicals, where nitrogen is optionally incorporated into the membrane. Examples of N-H-containing free radicals include, but are not limited to, free radicals of methylamine, dimethylamine and aniline. The aforementioned free radical species may be generated from a gas including hydrogen, nitrogen, N-H-containing species, or a mixture thereof. In some embodiments, substantially all of the atoms of the deposited film are provided by precursor molecules. In such cases, the low-energy free radicals used to drive the deposition reaction may be only hydrogen, or other species that do not substantially contribute to the quality of the deposited layer. In some embodiments, as discussed further below, free radical species may be generated by a remote plasma source. In some embodiments, higher energy free radicals or even ions can potentially exist near the wafer plane.

In some embodiments, the process conditions employ a radical species in a substantially low energy state sufficient to break the Si-H bond and / or the Si-Si bond to retain or substantially retain the Si-O bond and the Si-C bond. Such process conditions may not have ionic, electronic, or free radical species in a solid mass, such as in a high energy state above the ground state. In some embodiments, the ion concentration in a region adjacent to the membrane is no greater than about 107 / cm ³ . The presence of real-mass ions or high-energy free radicals may tend to break Si-O bonds or Si-C bonds, which may result in undesirable electrical properties (e.g., high dielectric constant and / or low breakdown voltage) and poor conformation Degree of film. It is believed that an over-reactive environment produces reactive precursor fragments with high adhesion coefficients (representing a tendency to adhere chemically or physically to the side wall of a workpiece), resulting in poor conformality.

In the environment adjacent to the substrate 100, the silicon-containing precursor is typically transported together with other species, especially a carrier gas. In some embodiments, the silicon-containing precursor system is present along with free radical species and other species, including other reactive species and / or carrier gases. In some embodiments, the silicon-containing precursor may be introduced as a mixture. Upstream of the deposition reaction surface, the silicon-containing precursor can be mixed with an inert carrier gas. Exemplary inert carrier gases include, but are not limited to, nitrogen (N ₂ ), argon (Ar), and helium (He). In addition, the silicon-containing precursor may be introduced into a mixture having a primary and secondary species, with the secondary species containing some elements or structural features present in the oxygen-doped silicon carbide film 101 at a relatively low concentration (for example, Ring structure, cage structure, unsaturated bond, etc.). The plurality of precursors may suitably exist in an equal molar concentration or a relatively similar ratio to form a backbone or a matrix in the resulting oxygen-doped silicon carbide film 101. In other embodiments, the relative amounts of different precursors are substantially offset from the isomolar concentration.

In some embodiments, one or more silicon-containing precursors provide substantially all of the mass of the deposited silicon carbide film, with a small amount of hydrogen or other elements from the remote plasma providing less than about 5% atomic percent of the film mass Or less than about 2% atomic percent. In some embodiments, only free radical species and one or more silicon-containing precursors contribute to the composition of the deposited silicon carbide film. In other embodiments, the deposition reaction includes co-reactants other than one or more silicon-containing precursors and free radical species. Examples of such co-reactants include the following: carbon dioxide (CO ₂ ), carbon monoxide (CO), water (H ₂ O), methanol (CH ₃ OH), oxygen (O ₂ ), ozone (O ₃ ), nitrogen (N ₂ ), nitrogen oxide ((N ₂ O), ammonia (NH ₃ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), two Boranes, and combinations thereof. Such materials can be used as nitriding agents, oxidants, reducing agents, etc. In some cases, these materials can be used to remove a portion of the carbon provided with the silicon-containing precursor. The amount of carbon in the deposited film is adjusted. In some embodiments using a hydrogen-free co-reactant, the co-reactant is introduced into the reactor via the same flow path as the silicon-containing precursor; for example, including a shower head, Paths that are typically not directly exposed to the plasma. In some embodiments, oxygen and / or carbon dioxide are introduced with the precursor to change the silicon carbide film by removing carbon from the film or precursor during deposition In some embodiments using a hydrogen-free co-reactant, the co-reactant is introduced into the reactor via the same flow path as hydrogen, making the co-reaction Was at least partially converted into radicals and / or ions. In such an embodiment, a hydrogen radical and a radical coreactant with both the silicon carbide film containing silicon precursor (s) to produce a reaction deposited.

In certain embodiments where a co-reactant is used and the co-reactant is introduced into the chamber together with a species that is converted to a free radical (e.g., hydrogen), compared to other gases in the reactor (including, for example, hydrogen Source, such as any (plural) carrier gas of helium), the co-reactant is provided to the reactor in a relatively small amount. For example, the co-reactant may be present in the process gas at about 0.05% by mass or less, or about 0.01% by mass or less, or about 0.001% by mass or less. For example, the reactant mixture (which enters the plasma source) can be about 10 L / m He, about 200-500 sccm H _2, and about 1-5 sccm oxygen. When the co-reactant is introduced into the chamber together with the silicon-containing precursor (eg, through a showerhead), it can be present at a higher concentration; for example, about 2% or less, or about 0.1% or less. When the co-reactant is a relatively weak reactant (e.g., a weak oxidant such as carbon dioxide), it can be present at even higher concentrations, such as about 10% or less, or about 4% or less.

The temperature in the environment adjacent to the substrate 100 may be any suitable temperature that promotes the deposition reaction, but is sometimes limited to the application of a device including an oxygen-doped silicon carbide film 101. The temperature in the environment adjacent to the substrate 100 can be greatly controlled by the temperature of the pedestal, and the substrate 100 is supported on the pedestal during the deposition of the oxygen-doped silicon carbide film 101. In some embodiments, the operating temperature may be between about 50 ° C and about 500 ° C. For example, in many integrated circuit applications, the operating temperature can be between about 250 ° C and about 400 ° C. In some embodiments, increasing the temperature may cause an increase in cross-linking on the substrate surface.

The pressure in the environment adjacent to the substrate 100 may be any suitable pressure that generates reactive radicals in the process chamber. In some embodiments, the pressure may be about 35 Torr or lower. For example, in embodiments using a plasma generated by microwaves, the pressure may be between about 10 Torr and about 20 Torr. In other examples, such as in embodiments using a radio frequency (RF) generated plasma, the pressure may be less than about 5 Torr or between about 0.2 Torr and about 5 Torr.

1B-1E illustrate cross sections of structures containing oxygen-doped silicon carbide films in various applications. FIG. 1B illustrates an oxygen-doped silicon carbide vertical structure on a sidewall of a gate electrode structure of a transistor. FIG. 1C illustrates an oxygen-doped silicon carbide vertical structure on exposed sidewalls of a copper wire in an air-gap type metallization layer. FIG. 1D illustrates an oxygen-doped silicon carbide hole seal for a porous dielectric material. FIG. 1E illustrates an oxygen-doped silicon carbide spacer through the integration flow of a finFET structure. Each of these applications is discussed in further detail below. Chemical structure of precursor

As discussed, the precursors used in forming the oxygen-doped silicon carbide film may include silicon-containing precursors, and at least some of the silicon-containing precursors have at least one Si-H bond and / or at least one Si-Si bond. In some embodiments, the silicon-containing precursor has at most one hydrogen atom on each silicon atom. Thus, for example, a precursor having one silicon atom has at most one hydrogen atom bonded to the silicon atom; a precursor having two silicon atoms has one hydrogen atom bonded to one silicon atom, and optionally has Another hydrogen atom bonded to a second silicon atom; a precursor having three silicon atoms has at least one hydrogen atom bonded to one silicon atom, and optionally one or both of the remaining silicon atoms One or two additional hydrogen atoms, and so on. In addition, the silicon-containing precursor may include at least one Si-O bond and / or at least one Si-C bond. Although any number of suitable precursors can be used in forming the oxygen-doped silicon carbide film, at least some of the precursors will include having at least one Si-H bond or Si-Si bond, and optionally having at least one Si-O bond And / or Si-C bond silicon-containing precursors. In some embodiments, the (plural) silicon-containing precursor does not contain an O-C bond, for example, the (plural) precursor does not contain an alkoxy group (-O-R), where R is an organic group such as a hydrocarbon group.

In some embodiments, at least some of the carbon provided for the oxygen-doped silicon carbide film is provided by one or more hydrocarbon functional groups on the silicon-containing precursor. Such a functional group may be derived from a hydrocarbyl group, an alkenyl group, an alkynyl group, an aryl group, and the like. In certain embodiments, the hydrocarbon group has a single carbon atom to minimize the steric hindrance of the Si-H bond and / or Si-Si bond breaking reaction during deposition. However, the precursor is not limited to a single carbon group; a larger number of carbon atoms can still be used, such as 2, 3, 4, 5, or 6 carbon atoms. In certain embodiments the hydrocarbon groups are linear. In certain embodiments, the hydrocarbon group is cyclic.

In some embodiments, the silicon-containing precursor falls into one of three or more chemical categories, any of which may exist alone as a single precursor or in combination with other types of precursors. I will understand that other chemical classes of silicon-containing precursors may be used and that the silicon-containing precursor is not limited to the chemical classes discussed below.

First, the silicon-containing precursor may be a siloxane. In some embodiments, the siloxane may be ring-shaped. Cyclosiloxanes may include, for example, 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS), octamethylcyclotetrasiloxane (OMCTS) and heptamethylcyclotetrasiloxane (HMCTS) Of cyclotetrasiloxane. Other cyclic siloxanes may also include, but are not limited to, cyclotrisiloxane and cyclopentasiloxane. An embodiment using a ring-shaped siloxane is a ring structure that can introduce porosity into an oxygen-doped silicon carbide film, and the hole size corresponds to the ring radius. For example, a cyclotetrasiloxane ring may have a radius of about 6.7 Å.

In some embodiments, the siloxane may have a three-dimensional or cage-like structure. Figure 2 illustrates an example of a representative caged siloxane precursor. Cage siloxanes have silicon atoms bridged to each other via oxygen atoms to form a polyhedron or any 3D structure. An example of a caged silicone precursor molecule is silsesquioxane. The cage siloxane structure is described in further detail in US Patent No. 6,576,345, co-owned by Cleemput et al., Which is incorporated herein by reference in its entirety and for all purposes. Similar to cyclic siloxanes, cage siloxanes introduce porosity into oxygen-doped silicon carbide films. In some embodiments, the pore size is mesopores.

In some embodiments, the siloxane is linear. Examples of suitable linear siloxanes include, but are not limited to, disilanes such as pentamethyldisilazane (PMDSO) and tetramethyldisilaxane (TMDSO), and such as hexamethyltrisiloxane, Heptamethyltrisiloxane.

Second, the silicon-containing precursor may be a hydrocarbon-based silane or another hydrocarbon-substituted silane. The hydrocarbyl silane includes a central silicon atom, one or more hydrocarbyl groups are bonded to the central silicon atom, and one or more hydrogen atoms are bonded to the central silicon atom. In certain embodiments, any one or more of the hydrocarbyl groups contain 1-5 carbon atoms. Hydrocarbon groups can be saturated or unsaturated (eg, alkenyl groups (eg, vinyl), alkynyl groups, and aromatic groups). Examples include, but are not limited to, trimethylsilane (3MS), triethylsilane, pentamethyldisilamethane ((CH3) 2Si-CH2-Si (CH3) 3), and dimethylsilane (2MS).

Third, the silicon-containing precursor may be an alkoxysilane. The alkoxysilane includes a central silicon atom, one or more alkoxy groups are bonded to the central silicon atom, and one or more hydrogen atoms are bonded to the center. Silicon atom bonding. Examples include, but are not limited to, trimethoxysilane (TMOS), dimethoxysilane (DMOS), methoxysilane (MOS), methyldimethoxysilane (MDMOS), diethoxymethylsilane (DEMS) ), Dimethylethoxysilane (DMES) and dimethylmethoxysilane (DMMOS).

In addition, disilane, trisilane, or other higher silanes can be used instead of monosilane. In some embodiments, one of the silicon atoms may have a carbon-containing or hydrocarbon-containing group attached to the silicon atom, and one of the silicon atoms may have a hydrogen atom attached to the silicon atom.

In depositing oxygen-doped silicon carbide, a plurality of silicon-containing precursors may be present in the process gas. For example, a siloxane and a hydrocarbylsilane may be used together, or a siloxane and an alkoxysilane may be used together. The relative proportions of individual precursors can be selected based on the chemical structure of the selected precursor and the application that results in the oxygen-doped silicon carbide film. For example, in mole percentages, the amount of siloxane may be greater than the amount of silane to produce a porous membrane as discussed in detail below.

For the deposition of oxygen-doped silicon carbide films, examples of suitable precursors include ring silicon such as cyclotetrasiloxane (such as heptamethyltrisiloxane (HMCTS) and tetramethylcyclotetrasiloxane (TMCTS)). Oxane. Other cyclic siloxanes may also include, but are not limited to, cyclotrisiloxane and cyclopentasiloxane. For the deposition of oxygen-doped silicon carbide films, examples of suitable precursors include linear siloxanes such as, but not limited to, disiloxanes (such as pentamethyldisilazane (PMDSO), TMDSO), hexamethyltrisiloxane and heptamethyltrisiloxane).

As explained, the silicon-containing precursor is selected to provide a highly conformal silicon carbide film. It is believed that silicon-containing precursors with low adhesion coefficients can produce highly conformal films. "Adhesion coefficient" is a term used to describe the number of adsorbate species (e.g., fragments or molecules) adsorbed / adhered to the substrate surface during the same period of time compared to the number of species impacted on the surface ratio. The symbol S _{c is} sometimes used to indicate the adhesion coefficient. The value of S _c is between 0 (meaning no species adhesion) and 1 (meaning all impact species adhesion). Different factors affect the adhesion coefficient, including the type of impact species, surface temperature, surface coverage, surface structural details, and kinetic energy of impact species. Some species are more "sticky" in nature than others, making them more likely to adhere to the substrate surface each time they impact the substrate surface. These more sticky species have higher adhesion coefficients (all other factors being equal), and are more likely to be adsorbed at the entrances of adjacent depression features than the less sticky species with lower adsorption coefficients. In some cases, the precursor's adhesion coefficient (under relevant deposition conditions) may be about 0.05 or less, such as about 0.001 or less. Structure and characteristics of the deposited film

The deposited film will include silicon, oxygen, and carbon. In some embodiments, the atomic concentration of silicon is between about 15% and 45%, the atomic concentration of oxygen is between about 10% and 40%, and the atomic concentration of carbon is between about 30% and 60%. In one example, the atomic concentration of silicon is about 30%, the atomic concentration of oxygen is about 25%, and the atomic concentration of carbon is about 45%. I will understand that the relative atomic concentration may vary depending on the choice of precursor. The silicon atom will form a bond with carbon and / or oxygen. In some embodiments, the deposited film contains more Si-O bonds than Si-C bonds. This can provide a relatively porous film with a lower dielectric constant. In some examples, the deposited film contains a Si-O bond to Si-C bond ratio between 0.5: 1 and 3: 1.

In some embodiments, the internal structure of the precursor is maintained in the deposited film. This structure can retain all or most of the Si-C bonds and Si-O bonds in the precursor, through the Si-H bonds and / or Si-Si bond positions existing in the precursor molecules, and / Or through additional coagulation reactions on the growth surface (if sufficient thermal energy is provided), to link or crosslink individual precursor functional groups.

The previously described process conditions can provide a highly conformal film structure. Relatively moderate process conditions can minimize the degree of ion bombardment at the substrate surface, making the deposition lack directionality. In addition, relatively moderate process conditions can reduce the number of free radicals with high adhesion coefficients that will have a tendency to adhere to the sidewalls of previously deposited layers or films. In some embodiments, for an aspect ratio of about 2: 1 to 10: 1, the oxygen-doped silicon carbide film may be deposited with between about 25% and 100%, more typically between about 50% and 100 Conformality between% and even more typically between about 80% and 100%. The conformity can be calculated by comparing the average thickness of the deposited film on the bottom, sidewall, or top of the feature with the average thickness of the deposited film on the bottom, sidewall, or top of the feature. For example, the shape retention can be calculated by dividing the average thickness of the deposited film on the sidewall of the feature by the average thickness of the deposited film at the top and multiplying by 100 to obtain a percentage. For some applications, a shape retention between 85% and 95% is sufficient. In some examples where silicon carbide is deposited on a feature having an aspect ratio between about 2: 1 and about 4: 1, the conformality is at least about 90%. Some back-end processes (BEOL) fall into this category. In some examples where silicon carbide is deposited on features having an aspect ratio between about 4: 1 and about 6: 1, the conformality is at least about 80%. Some spacer deposition processes fall into this category. In some examples where silicon carbide is deposited on features having an aspect ratio between about 7: 1 and about 10: 1 (and even higher), the conformality is at least about 90%. Some DRAM (Dynamic Random Access Memory) manufacturing processes fall into this category.

This process condition can also provide a film structure with high breakdown voltage and low leakage current. By introducing a limited amount of oxygen into a SiC-type material, the leak path provided by Si-H bonds and / or Si-CH ₂ -Si bonds can be blocked by oxygen. This can provide improved electrical properties while maintaining a relatively low dielectric constant. In various embodiments, the film has about 4.5 or less, about 4.0 or less, about 3.5 or less, and in some embodiments about 3.0 or less, and in still other embodiments about 2.5 or Lower effective dielectric constant. The effective dielectric constant may depend on the bonding and density. In some applications that require a relatively high dielectric constant, the oxygen-doped silicon carbide film may have an effective dielectric constant greater than about 4.0 to provide a relatively dense, highly cross-linked oxygen-doped silicon carbide film. In some embodiments, the oxygen-doped silicon carbide film may be relatively thin and still serve as a sealing and diffusion barrier.

In some embodiments, the deposited film may be porous. As previously discussed herein, the silicon-containing precursors may include cyclic siloxane and cage siloxane. These precursors, and others with significant internal open spaces, can introduce significant porosity into the structure of the deposited film. The porosity in the deposited film can further reduce the dielectric constant. In some embodiments, the porosity in the deposited oxygen-doped silicon carbide film is between about 20% and 50%. The pore size of the porous membrane can follow the pore size of the annular or cage precursor. In some embodiments, the average pore size of the film is between about 5 Å and 20 Å, such as about 16 Å.

The oxygen-doped silicon carbide film deposited by the method of the present disclosure may have a chemical structure that can be distinguished from a conventional SiOC film. Although the oxygen-doped silicon carbide film deposited by the method of the present disclosure may be referred to as a SiOC film or a SiCO film, it will be understood that the conventional SiOC film does not have the SiOC film or SiCO as deposited by the method of the present disclosure. The membranes generally have the same chemical structure or characteristics. In some embodiments, the conventional SiOC film may be a carbon-doped silicon oxide film that can be distinguished from the SiOC or SiCO film of the present disclosure. FIG. 4A shows an exemplary chemical structure of a conventional SiOC film. FIG. 4B shows an exemplary chemical structure of an oxygen-doped silicon carbide (SiOC or SiCO) film deposited by the method of the present disclosure.

Many conventional deposition techniques form a conventional SiOC or SiOC: H having a chemical structure similar to that shown in Figure 4A. For example, such a SiOC or SiOC: H film is formed by using carbon-doped silicon dioxide (SiO ₂ ). As shown in Figures 4A, so SiOC or SiOC: H film comprising a plurality of terminal CH ₃ bond, an oxygen atom wherein the carbon atom and a hydrogen atom-coordinated. The carbon atoms or at least a substantial portion of the carbon atoms are non-crosslinked. In addition, the SiOC or SiOC: H film in FIG. 4A has a relatively high hydrogen content. The carbon-doped silicon oxide structure as shown in FIG. 4A may retain different characteristics from the oxygen-doped silicon carbide structure of the present disclosure shown in FIG. 4B.

The method of this disclosure produces an oxygen-doped silicon carbide (SiOC or SiCO) film having a chemical structure similar to that shown in FIG. 4B. For example, such an oxygen-doped silicon carbide film may be formed by reacting one or more radical species (e.g., hydrogen radicals) in a substantially low energy state (e.g., ground state) with one or more silicon-containing precursors, where the One or more free radical species are generated from a remote plasma source. As shown in Figure 4B, the oxygen doped silicon carbide film comprises little to no terminal CH ₃ bonds, wherein the carbon atoms and a substantially crosslinked by Si atoms coordinated. The carbon atoms or at least a substantial portion of the carbon atoms are cross-linked and are not coordinated by hydrogen or oxygen atoms. In addition, the oxygen-doped silicon carbide film in FIG. 4B has a relatively low hydrogen content.

The characteristics of the deposited oxygen-doped silicon carbide film can be compared with the characteristics of a carbon-doped silicon oxide film or a conventional SiOC film. A conventional SiOC or SiOC: H film having a structure similar to that shown in FIG. 4A can be easily hydrolyzed and has a relatively low energy state. For example, Si-O-CH ₃ can be easily hydrolyzed to Si-OH and HO-CH ₃ . In the case where the silicon atom is coordinated by an oxygen atom in FIG. 4A, the polarity of the Si-O bond causes the film to become more vulnerable to fluorination and subsequent dissociation during an etching process such as an HF wet etching process. The higher polarity of the Si-O bond relative to the Si-C bond increases the reactivity to the acid. However, an oxygen-doped silicon carbide film having a structure similar to that shown in FIG. 4B is not easily hydrolyzed, but the reaction is slow and requires high energy. For example, Si-C-Si is not easily hydrolyzed. In the case where the carbon atoms in FIG. 4B are coordinated by silicon atoms, the polarity of the Si-C bond causes the film to be less vulnerable to fluorination and subsequent dissociation during an etching process such as an HF wet etching process. The relative non-polarity of Si-C bonds compared to Si-O bonds makes oxygen-doped silicon carbide films more inert to acids. Accordingly, in some embodiments, the oxygen-doped silicon carbide film may have better wet etching resistance than the carbon-doped silicon oxide film.

5A illustrates a Fourier transform infrared spectroscopy (FTIR) plot of the chemical stability of a conventional SiOC or SiOC: H film. FTIR mapping shows that the film contains Si-CH ₃ bonds, Si-C bonds, and Si-O-Si bonds during deposition. After being exposed to an etching process such as an O ₂ / N ₂ stripping process, the Si—CH ₃ bond largely disappears. The terminal CH ₃ bond can be easily removed, so that after the O ₂ / N ₂ stripping process, only the Si-C bond and the Si-O-Si bond remain in large quantities. This shows that the exemplary conventional SiOC or SiOC: H film is not chemically stable, especially when exposed to an etching process.

FIG. 5B illustrates a thermal desorption spectrum (TDS) plot of the thermal stability of a conventional SiOC or SiOC: H film. TDS plots show that molecules of CH ₃ and H ₂ are desorbed from the substrate surface at higher temperatures, for example, temperatures greater than 600 ° C. The terminal CH ₃ bond can be easily decomposed at higher temperatures, and more hydrogen will be desorbed from a conventional SiOC or SiOC: H film with an increased hydrogen content. This shows that conventional SiOC or SiOC: H films are not thermally stable, especially when exposed to elevated temperatures.

FIG. 6A illustrates a FTIR plot of the chemical stability of an oxygen-doped silicon carbide (SiOC or SiCO) film deposited by the method of the present disclosure. FTIR mapping shows that the film contains Si-O-Si bonds and Si-C bonds but no Si-CH ₃ bonds. After exposure to an etch process such as an O ₂ / N ₂ stripping process, the FTIR pattern remains the same. This shows that the exemplary oxygen-doped silicon carbide film is chemically stable, especially when exposed to an etching process.

FIG. 6B illustrates a TDS plot of the thermal stability of an oxygen-doped silicon carbide film deposited by the method of the present disclosure. TDS plots show that at higher temperatures, for example, temperatures above 600 ° C, the molecules of CH ₃ do not desorb from the surface of the substrate. Further, compared to FIG. 5B, fewer H ₂ molecules are desorbed from the substrate surface in FIG. 6B. This shows that the oxygen-doped silicon carbide film deposited by the method of the present disclosure is thermally stable.

Therefore, the oxygen-doped silicon carbide film may have a low etch rate, may be thermally stable, and may be chemically stable. This allows the film to withstand high temperature annealing, dry / wet etching, ashing, and other manufacturing processes. Without being bound by any theory, this robustness may be due in part to the cross-linked Si-C bonding and the lack of terminal CH ₃ bonds. This type of film can provide significant performance improvements in semiconductor applications such as low-k spacer applications.

Compared to other conventional dielectric materials including SiOC / SiOC: H, SiO ₂ and SiBCN, oxygen-doped silicon carbide films can provide improved characteristics. Oxygen-doped silicon carbide films not only provide low-k dielectrics, oxygen-doped silicon carbide films also provide high breakdown voltage, high chemical stability, high thermal stability, and strong resistance to wet etching. Such an oxygen-doped silicon carbide film is useful in applications requiring low-k spacers that involve an integrated process of different thermal annealing and etching steps, where the oxygen-doped silicon carbide film can withstand the integrated process while maintaining Low k value. Conventional SiOC / SiOC: H, SiO ₂ and SiBCN films can provide low k values but may not be able to withstand such integration processes. device

One embodiment of the disclosure is a device configured to implement the methods described herein. Suitable equipment includes hardware for implementing process operations, and a system controller having instructions for controlling process operations according to the disclosure. In some embodiments, the equipment used to perform the aforementioned process operations may include a remote plasma source. Compared to direct plasma sources, remote plasma sources provide moderate response conditions. An example of a suitable remote plasma device is described in US Patent Application No. 14 / 062,648 filed on October 24, 2013, which is incorporated herein by reference in its entirety.

Figure 3 presents a schematic diagram of a remote plasma apparatus according to some embodiments. The apparatus 300 includes a reaction chamber 310 having a showerhead assembly 320. In the reaction chamber 310, a substrate 330 is placed on a base or pedestal 335. In some embodiments, the base 335 may be equipped with heating / cooling elements. The controller 340 may be connected to elements of the device 300 to control the operation of the device 300. For example, the controller 340 may contain instructions or process conditions for the operation of the device 300, such as temperature process conditions and / or pressure process conditions.

During operation, a gas or gas mixture is introduced into the reaction chamber 310 via one or more gas inlets coupled to the reaction chamber 310. In some embodiments, two or more gas inlets are coupled to the reaction chamber 310. The first gas inlet 355 may be coupled to the reaction chamber 310 and connected to the container 350, and the second gas inlet 365 may be coupled to the reaction chamber 310 and connected to a remote plasma source 360. In embodiments that include a remote plasma configuration, the delivery lines for the precursors and the free radical species generated in the remote plasma source are separate. Therefore, the precursor and the radical species do not substantially interact with each other before reaching the substrate 330.

One or more free radical species may be generated in the remote plasma source 360 and configured to enter the reaction chamber 310 via a gas inlet 365. Any type of plasma source can be used in the remote plasma source 360 to generate free radical species. This includes, but is not limited to, capacitive coupling plasma, inductively coupled plasma, microwave plasma, DC plasma and laser-generated plasma. An example of a capacitive coupling plasma is a radio frequency (RF) plasma. The high-frequency plasma can be configured to operate at 13.56 MHz or higher. An example of such a remote plasma source 360 is GAMMA® produced by Novellus Systems of San Jose, California. Another example of such an RF remote plasma source 360 may be Astron® manufactured by MKS Instruments of Wilmington, Massachusetts, which can operate at a frequency of 440 kHz and can be used as a bolt to process one or more substrates in parallel It is provided on a larger unit. In some embodiments, the microwave plasma can be used as a remote plasma source 360, such as Astex® also produced by MKS Instruments. The microwave plasma can be configured to operate at a frequency of 2.45 GHz.

The precursor may be provided in the container 350 and may be supplied to the shower head 320 via the first gas inlet 355. The shower head 320 distributes the precursors toward the substrate 330 into the reaction chamber 310. The substrate 330 may be located below the shower head 320. It will be appreciated that the showerhead 320 may have any suitable shape and may have any number and arrangement of ports for distributing gas to the substrate 330. The precursor may be supplied to the shower head 320 at a controlled flow rate, and finally supplied to the substrate 330.

One or more radical species formed in the remote plasma source 360 may be carried toward the substrate 330 in the gas phase. One or more free radical species may flow through the second gas inlet 365 into the reaction chamber 310. I will understand that the second gas inlet 365 need not be transverse to the surface of the substrate 330 as illustrated in FIG. 3. In some embodiments, the second gas inlet 365 may be located directly above the substrate 330 or in other locations. The distance between the remote plasma source 360 and the reaction chamber 310 may be configured to provide moderate reaction conditions such that the ionized species generated in the remote plasma source 360 are substantially neutralized, but at least some are in a substantially low energy state Of free radical species remain in the environment adjacent to the substrate 330. Such low-energy free radical species no longer combine to form stable compounds. The distance between the remote plasma source 360 and the reaction chamber 310 may be a function of the aggressiveness of the plasma (e.g., determined in part by the source RF power level), the density of the gas in the plasma (e.g., If there is a high concentration of hydrogen atoms, a significant portion of the hydrogen atoms may recombine before reaching the reaction chamber 310 to form H ₂ ) and other factors. In some embodiments, the distance between the remote plasma source 360 and the reaction chamber 310 may be between about 10 cm and 50 cm, such as about 30 cm.

In some embodiments, a co-reactant may be introduced during the deposition reaction, which is not the main silicon-containing precursor or hydrogen radical. In some embodiments, the device is configured to introduce the co-reactant through the second gas inlet 365, in which case the co-reactant is at least partially converted into a plasma. In some embodiments, the apparatus is configured to introduce the co-reactants through the showerhead 320 via the first gas inlet 355. Examples of co-reactants include oxygen, nitrogen, carbon dioxide, and the like.

The controller 340 may include instructions for controlling process conditions for the operation of the device 300. The controller 340 will typically include one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, a stepper motor controller board, and so on. The instructions used to implement the appropriate control operations are executed on the processor. The instructions may be stored on a memory device associated with the controller 340, or it may be provided on a network.

In some embodiments, the controller 340 controls all or most of the activities of the semiconductor processing device 300 described herein. For example, the controller 340 may control all or most of the activities of the semiconductor processing device 300 associated with depositing an oxygen-doped silicon carbide film and (optionally) other operations in the manufacturing process including the oxygen-doped silicon carbide film. The controller 340 may execute system control software including control sequences, gas composition, gas density, gas flow rate, chamber pressure, chamber temperature, RF power level, substrate position, and / or other parameters. Instruction set. In some embodiments, other computer programs, scripts or common programs stored on the memory device associated with the controller 340 may be used. In order to provide relatively moderate response conditions in the environment adjacent to the substrate 330, parameters such as RF power level, gas flow rate to a remote plasma region, and plasma excitation timing can be adjusted and maintained by the controller 340. In addition, adjusting the position of the substrate can further reduce the occurrence of high-energy radical species in the environment adjacent to the substrate 330.

In a multiple station reactor, the controller 340 may contain different or identical instructions for different equipment stations, thus allowing the equipment stations to operate independently or synchronously.

In some embodiments, the controller 340 may include instructions for performing operations such as: flowing a silicon-containing precursor into the reaction chamber 310 through the first gas inlet 355, One or more radical species in a low energy state and one or more radical species are allowed to flow into the reaction chamber 310 through the second gas inlet 365 to react with the silicon-containing precursor to form oxygen-doped silicon on the substrate 330 Carbide film.

In some embodiments, the device may include a user interface associated with the controller 340. The user interface may include graphical software displays and user input devices (eg, pointing devices, keyboards, touch screens, microphones, etc.) that display screens, equipment, and / or process conditions.

The computer code for controlling the above operations can be written in any conventional computer-readable programming language: for example, combinatorial language, C, C ++, Pascal, Fortran, or others. The compiled object code or script is executed by the processor to perform the tasks identified in the program.

The signals used to monitor the process can be provided by analog and / or digital input connections of the system controller. The signals used to control the process are output on the analog and digital output connections of the processing system.

In general, the methods described herein can be performed on a system including semiconductor processing equipment such as (plural) processing tools, (plural) chambers, (plural) processing platforms, and / or specific processing elements ( Wafer pedestals, gas flow systems, etc.). The system can be integrated with electronics to control the operation of the system before, during, and after the processing of semiconductor wafers or substrates. Generally speaking, the electronic device is called a "controller", which can control various elements or sub-components of the system or plural systems. Depending on the processing conditions and / or system type, the system controller can be programmed to control any of the processes disclosed herein, including the transfer of process gas, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, Power setting, radio frequency (RF) generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid transfer setting, position and operation setting, wafer transfer (in and out of a tool connected to or connected to a specific system, and other transfer tools , And / or loading room).

Broadly speaking, a controller can be defined as an electronic device with various integrated circuits, logic, memory, and / or software for receiving instructions, issuing instructions, controlling operations, starting cleaning operations, starting endpoint measurements, and the like. . Integrated circuit may include: a chip in the form of firmware storing program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuits (ASIC), and / or Or more microprocessors, or microcontrollers that execute program instructions (eg, software). Program instructions can be instructions that are communicated to the controller or system in the form of various individual settings (or program files) that are implemented in a specific process (on a semiconductor wafer or for semiconductor wafers) ) Define the operating parameters. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to achieve one or more processing steps during manufacturing of one or more of the following: stack, material (e.g., silicon carbide), Surface, circuit, and / or die of the wafer.

In some embodiments, the controller may be part of a computer, or coupled to a computer, which is integrated with the system, coupled to the system, connected to the system through other networks, or a combination thereof. system. For example, the controller may be in all or part of a "cloud" or factory host computer system that allows remote access to wafer processing. The computer enables the system to be remotely accessed to monitor the current progress of manufacturing operations, check the history of past manufacturing operations, and check trends or performance metrics from multiple manufacturing operations to change the parameters of current processing and set processing after current processing Steps, or start a new process. In some examples, a remote computer (eg, a server) may provide process recipes to the system through a network, which may include a local area network or the Internet. The remote computer may include a user interface that allows access to or programming of the parameters and / or settings, and the parameters and / or settings are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data that specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may specifically target the type of process to be performed and the type of tool with which the controller engages or controls. Thus, as described above, the controllers may be decentralized, such as by including one or more separations that are connected together in a networked manner and that operate toward a common purpose (e.g., the processes and controls described herein). Controller. An example of a decentralized controller for this purpose would be one of the chambers that communicates with one or more integrated circuits located remotely (e.g. at the platform level or as part of a remote computer) or More integrated circuits, the two are combined to control the process on the chamber.

In addition to the oxygen-doped silicon carbide deposition described herein, the exemplary system may include a plasma etching chamber or module, a deposition chamber or module, a spin bath or module, a metal plating chamber, or Module, cleaning chamber or module, beveled edge etching chamber or module, physical vapor deposition deposition (PVD) chamber or module, chemical vapor deposition (CVD) chamber or module, atomic layer ALD chamber or module, atomic layer etching (ALE) chamber or module, ion implantation chamber or module, track chamber or module, and can be associated with or used for Any other semiconductor processing system in the manufacture and processing of semiconductor wafers.

As mentioned above, depending on the (plural) process steps to be performed by the tool, the controller can communicate with one or more of the following in the semiconductor processing plant: other tool circuits or modules, other tool components , Cluster tools, other tool interfaces, adjacent tools, adjacent tools, tools distributed throughout the factory, host computer, another controller, or tools used in material transfer, which are used in the material transfer The tool brings or brings the wafer container to or from the tool location and / or loading port. application

This disclosure can be further understood by referring to the following applications of high-quality oxygen-doped silicon carbide (SiOC or SiCO) films, which are intended to be purely exemplary. This disclosure is not limited to the scope of specific applications, and these specific applications are merely illustrations of the implementation aspects of this disclosure.

In some embodiments, an oxygen-doped silicon carbide film may be deposited on the exposed copper. In some embodiments where an oxygen-doped silicon carbide film is deposited, the reaction conditions near the substrate may be free of oxidants such as O ₂ , O ₃ and CO ₂ , including their free radicals. Therefore, the oxygen-doped silicon carbide film can be deposited directly over the exposed copper without oxidizing the copper (eg, generating copper oxide). Such a film can be used as an etch stop layer, which can also be used as a copper diffusion barrier. The presence of an oxygen-doped silicon carbide film can provide a sufficiently low dielectric constant with excellent leakage characteristics to serve as a diffusion barrier. The oxygen-doped silicon carbide film itself can be used as an etch stop and / or diffusion barrier in a two-layer stack (for example, a SiCO / SiNC double-layer deposited on exposed copper). In some embodiments, an oxygen-doped silicon carbide film may be disposed between adjacent metallization layers, which are typically produced by a damascene process. The oxygen-doped silicon carbide film is resistant to etching and sufficiently dense to minimize the diffusion of copper ions into adjacent regions of the dielectric material. In some embodiments, the precursor used for the oxygen-doped silicon carbide film may be non-circular. Non-annular precursors may include PMDSO or TMDSO. Non-ring precursors can provide a sufficiently high density to serve as a seal or diffusion barrier. In some embodiments, nitrogen can be incorporated into the film layer by activating a nitrogen-containing radical (eg, an elemental nitrogen radical or an amine radical) with a nitrogen-containing precursor or a plasma.

In some embodiments, an oxygen-doped silicon carbide film may be deposited into a vertical structure adjacent to a metal or semiconductor structure. The deposition of oxygen-doped silicon carbide provides excellent step coverage along the sidewalls of the metal or semiconductor structure to produce a vertical structure. In some embodiments, the vertical structure may be referred to as a spacer or a pad. FIG. 1B illustrates a cross-sectional view of an oxygen-doped silicon carbide liner deposited on a sidewall of a gate electrode structure of a transistor. As shown in FIG. 1B, the transistor may be a CMOS transistor having a silicon substrate 110 (having a source 112 and a drain 113). A gate dielectric 114 may be deposited on the silicon substrate 110, and a gate electrode may be deposited on the gate dielectric 114 to form a transistor. Oxygen-doped silicon carbide spacers or pads 111 may be deposited on the sidewalls of the gate electrode 115 and the gate dielectric 114. In another example, FIG. 1C illustrates a cross section of an oxygen-doped silicon carbide deposited on a sidewall of an exposed copper wire in an air-gap type metallization layer. The air gap 120 may be introduced into the integrated circuit layer between the copper wires 122, which may reduce the effective k value of the layer. An oxygen-doped silicon carbide liner 121 may be deposited on a sidewall of the copper wire 122, and a non-conformal dielectric layer 123 may be deposited on the air gap 120, the liner 121, and the copper wire 122. An example of such an air-gap type metallization layer can be described in US Patent Application Publication No. 2004/0232552 by Fei Wang et al., Which is incorporated herein by reference in its entirety.

In some embodiments, an oxygen-doped silicon carbide film may be deposited on the sidewalls of the patterned porous dielectric material. A very low-k dielectric material may be composed of a porous structure. The holes in such a material can provide an area of metal entry during the deposition of a subsequent layer that includes the deposition of a diffusion barrier (containing a metal such as tantalum (Ta)). If too much metal migrates into the dielectric material, the dielectric material may provide a short circuit between adjacent copper metallization lines. FIG. 1D illustrates a cross-section of an oxygen-doped silicon carbide as a hole sealer for a porous dielectric material. The porous dielectric layer 132 may have a plurality of trenches or perforations cut into the porous dielectric layer 132 to form the holes 130. Oxygen-doped silicon carbide 131 may be deposited along the holes 130 to effectively seal the holes 130. The use of oxygen-doped silicon carbide 131 to seal the pores 130 can avoid damaging the porous dielectric layer 132. Damage to the porous dielectric layer 132 may be caused by other sealing techniques using plasma in other ways. The oxygen-doped silicon carbide 131 may be sufficiently dense as a hole sealer, and may include non-circular silicon-containing precursors such as PMDSO and TMDSO. In some embodiments, the etched dielectric material such as the porous dielectric layer 132 may be first processed by a "k-value recovery" process, which exposes the porous dielectric layer 132 to UV radiation and a reducing agent. This restoration process is further described in US Patent Application Publication No. 2011/0111533, which is co-owned by Varadarajan et al., Which is incorporated herein by reference in its entirety for all purposes. In another "k-value recovery" process, the porous dielectric layer 132 may be exposed to UV radiation and chemical silylating agents. This recovery process is further described in U.S. Patent Application Publication No. 2011/0117678, which is co-owned by Varadarajan et al., Which is incorporated herein by reference in its entirety for all purposes. After exposing the pores 130 to make the surface more hydrophilic and provide a single-layer recovery process, a layer of conformally deposited oxygen-doped silicon carbide 131 can be deposited to effectively seal the pores of the porous dielectric layer 132.

In some embodiments, the oxygen-doped silicon carbide film itself can be deposited as a very low-k dielectric material. Very low-k dielectrics are conventionally defined as materials with a dielectric constant below 2.5. In such a configuration, the very low-k dielectric material of oxygen-doped silicon carbide may be a porous dielectric layer. The holes in the dielectric layer can be introduced by using a ring-shaped or cage-shaped precursor molecule, the ring-shaped or cage-shaped precursor molecule including a cyclic siloxane and a silsesquioxane. In one example, the porosity of the very low-k dielectric layer of oxygen-doped silicon carbide can be between about 20% and 50%. Further, the extremely low-k dielectric layer may have an average hole size of less than about 100 Å, such as between about 5 Å and 20 Å. For example, a cyclosiloxane ring may have a radius of about 6.7 Å. Although increasing the number and size of holes can reduce the dielectric constant, if there are too many holes, the mechanical integrity of the dielectric layer may be damaged.

In some embodiments, the oxygen-doped silicon carbide film 151 may be deposited as a sidewall spacer in a fin-type field effect transistor (finFET) structure. As technology nodes in electronic components shrink and pitches become smaller, conductive features are positioned closer and closer. The separation between such conductive features becomes smaller, which can lead to an increase in parasitic capacitance. Parasitic capacitance can cause, for example, delays in the transmission of signals from the transistor to the interconnect. Materials with low dielectric constants can limit parasitic capacitance (especially when technology nodes shrink), rather than increasing the thickness of the dielectric material between conductive features.

Silicon nitride (Si ₃ N ₄ ) as a sidewall spacer can provide good step coverage, thermal stability, chemical stability, chemical selectivity, and high breakdown voltage. However, the dielectric constant of silicon nitride may be inappropriately high for many electronic components. A silicon dioxide (SiO ₂ ) film may maintain a low dielectric constant sufficient for many electronic components, but may not have sufficient wet etch resistance to withstand typical integration processes. The use of carbon or nitrogen-doped SiO ₂ films can improve their resistance to wet etching, but may still cause poor thermal and chemical stability. Oxygen-doped silicon carbide (SiCO) films can provide a sufficiently low dielectric constant with improved resistance to wet etching processes, thermal stability, chemical stability, high breakdown voltage, and excellent chemical selectivity With good step coverage. In this way, the oxygen-doped silicon carbide film can maintain a low dielectric constant and withstand integration processes involving different thermal annealing and etching steps.

FIG. 1E illustrates a three-dimensional schematic diagram of an example integration process used to fabricate a finFET structure. A finFET structure may include a plurality of gate electrodes (for example, polycrystalline silicon) parallel to each other, and a plurality of thin semiconductor materials "fins" parallel to each other and extending perpendicularly from both ends of the gate electrode. A fin extending from one side of the gate electrode may correspond to a source region, and a fin extending from an opposite side of the gate electrode may correspond to a drain region. Each top of the gate electrode can be covered with a gate mask. The oxygen-doped silicon carbide sidewall spacers 151 may be deposited conformally on the sidewalls of the fins and the gate electrodes, and on the top surfaces of the gate mask and the fins. The spacer etch removes a portion of the oxygen-doped silicon carbide sidewall spacer 151 from the gate mask of the fin and the gate electrode. The NMOS epitaxial growth step can form a source / drain region on the fin. The dielectric material may utilize an etch stop and / or a front metal dielectric to fill the finFET structure. The gate electrode can be subjected to lithographic processing steps for gate removal and metal filling. Such processing steps may involve one or more etching processes, wet cleaning processes, and photoresist stripping processes. The oxygen-doped silicon carbide sidewall spacer 151 may be stable throughout the entire process of such a processing step. The gate electrode may further undergo a contact or self-aligned contact (SAC) etch step, which may require selectivity in the oxygen-doped silicon carbide sidewall spacer 151, plasma resistance, and wet cleaning resistance.

Although the above has been described in detail for the purpose of clarity and understanding, it is clear that certain changes and modifications can be implemented within the scope of the accompanying patent application. It should be noted that there are many alternative ways to implement the processes, systems, and equipment described. Therefore, the described embodiments should be considered as illustrative and not restrictive.

100‧‧‧ substrate

101‧‧‧ oxygen-doped silicon carbide film

110‧‧‧ silicon substrate

111‧‧‧ cushion

112‧‧‧Source

113‧‧‧ Drain

114‧‧‧Gate dielectric

115‧‧‧Gate electrode

120‧‧‧air gap

121‧‧‧ cushion

122‧‧‧copper wire

123‧‧‧Dielectric layer

130‧‧‧ Hole

131‧‧‧ oxygen-doped silicon carbide

132‧‧‧ porous dielectric layer

151‧‧‧ oxygen-doped silicon carbide sidewall spacer

300‧‧‧ device

310‧‧‧ reaction chamber

320‧‧‧ sprinkler

330‧‧‧ substrate

335‧‧‧ base

340‧‧‧controller

350‧‧‧ container

355‧‧‧Gas inlet

360‧‧‧Remote Plasma Source

365‧‧‧Gas inlet

FIG. 1A illustrates a cross-section of an example of an oxygen-doped silicon carbide film deposited on a substrate.

FIG. 1B illustrates an oxygen-doped silicon carbide vertical structure on a sidewall of a gate electrode structure of a transistor.

FIG. 1C illustrates an oxygen-doped silicon carbide vertical structure on exposed sidewalls of a copper wire in an air-gap type metallization layer.

FIG. 1D illustrates an oxygen-doped silicon carbide hole seal for a porous dielectric material.

FIG. 1E illustrates a three-dimensional schematic diagram of an exemplary integration process for manufacturing a finFET structure.

Figure 2 illustrates an example of a representative caged siloxane precursor.

Figure 3 illustrates a schematic diagram of a processing facility with a remote plasma source.

FIG. 4A illustrates the chemical structure of an exemplary conventional silicon oxycarbide or carbon-doped silicon oxide (SiOC or SiOC: H).

FIG. 4B illustrates the chemical structure of an exemplary oxygen-doped silicon carbide (SiCO).

5A illustrates a Fourier transform infrared spectroscopy (FTIR) plot of the chemical stability of an exemplary conventional silicon oxycarbide or carbon-doped silicon oxide (SiOC or SiOC: H).

FIG. 5B illustrates a thermal desorption spectrum (TDS) plot of the thermal stability of an exemplary conventional silicon oxycarbide or carbon-doped silicon oxide (SiOC or SiOC: H).

6A illustrates a FTIR plot of the chemical stability of an exemplary oxygen-doped silicon carbide (SiCO).

6B illustrates a TDS plot of the thermal stability of an exemplary oxygen-doped silicon carbide (SiCO).

Claims (16)

A method for depositing an oxygen-doped silicon carbide (SiCO) film, the method comprising: providing a substrate; and flowing one or more silicon-containing precursors onto the substrate, wherein each of the one or more silicon-containing precursors Having: (i) one or more silicon-hydrogen bonds and / or silicon-silicon bonds and (ii) one or more silicon-oxygen bonds and one or more silicon-carbon bonds; allowing a source gas to flow to a remote location In a plasma source; generating hydrogen radicals from the source gas in the remote plasma source; and introducing the hydrogen radicals onto the substrate, wherein at least 90% of the radicals are in a substantially low energy state Free radicals of hydrogen that are in a substantially low energy state under conditions that break one or both of the silicon-hydrogen bond and the silicon-silicon bond but retain the silicon-oxygen bond and the silicon-carbon bond Reacting with one or more of the silicon-containing precursors to form a SiCO film on the substrate; For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 1 of the application, wherein the silicon-containing precursor includes a cyclic siloxane. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 2 of the application, wherein the cyclic siloxane is selected from the group consisting of TMCTS, OMCTS, and HMCTS. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 2 of the application, wherein the cyclic siloxane is a cage siloxane. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 1 of the application, wherein the silicon-containing precursor includes an alkoxysilane. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 1 of the application, wherein the silicon-containing precursor includes a hydrocarbon-based silane. The method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the radical is generated from a source gas of hydrogen. The method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein introducing the hydrogen radical includes exposing the source gas to a remote plasma. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 8 of the application, wherein the remote plasma is generated by an RF power source or a microwave power source. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the ratio of silicon-oxygen bonds to silicon-carbon bonds in the SiCO film is about 0.5: Between 1 and about 3: 1. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the SiCO film includes a conformal film on the substrate. For example, a method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the substrate includes exposed copper, and the method further includes forming the exposed copper directly over the exposed copper. SiCO film. For example, a method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the substrate includes an transistor having a gate electrode, and the method further includes the gate electrode. The SiCO film is formed on one or more sidewalls of the electrode. For example, a method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the substrate includes a dielectric having a plurality of holes, and the method further includes sealing using the SiCO film. The plural holes. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to any one of claims 1-6, wherein the SiCO film includes a very low-k dielectric film. For example, the method for depositing an oxygen-doped silicon carbide (SiCO) film according to item 15 of the application, wherein the extremely low-k dielectric film is porous.