Oxide film deposition using oxygen free plasma

Abstract

Aspects generally relate to methods and systems for processing substrates using oxide film deposition techniques with oxygen free plasma. The method includes forming an etch stop layer on a conductive layer and depositing an oxide film on the etch stop layer using an SiOCH-containing precursor and a carrier gas. In one example, the carrier gas is helium. In another example, the carrier gas is argon. In other examples, the carrier gas is combined with a hydrogen gas.

Description

PATENTAttorney Docket No.: 44024429WO01OXIDE FILM DEPOSITION USING OXYGEN FREE PLASMABACKGROUNDField

[0001] Aspects generally relate to methods and systems for processing substrates using oxide film deposition techniques with oxygen free plasma.Description of the Related Art

[0002] As semiconductor technology advances towards nodes as small as 1.4 nanometers (nm) and beyond, the control of metal gate oxidation becomes increasingly challenging due to the ultra-thin dimensions involved. Achieving precise control over the metal gate oxidation process at such scales calls for innovative techniques and stringent process optimization. Controlling the extent of metal gate oxidation beneficial in developing smaller and smaller semiconductor devices.

[0003] Therefore, there is a need for improved methods that facilitate deposition of materials that minimize or prevent metal gate oxidation.SUMMARY

[0004] Aspects generally relate to methods and systems for processing substrates using oxide film deposition techniques with oxygen free plasma.

[0005] In one implementation, a method includes forming an etch stop layer on a conductive layer and depositing an oxide film on the etch stop layer using an SiOCH- containing precursor and helium (He) carrier gas.

[0006] In one implementation, a method includes forming an etch stop layer on a conductive layer and depositing an oxide film on the etch stop layer using an SiOCH- containing precursor with a carrier gas and hydrogen (H2) gas.

[0007] In one implementation, a method includes forming an etch stop layer on a conductive layer and depositing an oxide film on the etch stop layer using an SiOCH- containing precursor and an argon (Ar) carrier gas.PATENTAttorney Docket No.: 44024429WO01BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of scope, as the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a cross-sectional view of a process chamber, according to one implementation.

[0010] Figures 2A-2D illustrate a process flow for depositing oxide films with oxygen free plasma, according to one implementation.

[0011] Figures 3A-3C illustrate three techniques for using SiOCH-containing precursors, according to one implementation.

[0012] Figure 4A is a flowchart for depositing an oxide film using an SiOCH- containing precursor and a helium (He) carrier gas, according to one implementation.

[0013] Figure 4B is a flowchart for depositing an oxide film using an SiOCH- containing precursor with a He carrier gas and hydrogen (H2) gas, according to one implementation.

[0014] Figure 4C is a flowchart for depositing an oxide film using an SiOCH- containing precursor with an argon (Ar) carrier gas and H2 gas, according to one implementation.

[0015] Figure 4D is a flowchart for depositing an oxide film using an SiOCH- containing precursor and an Ar carrier gas, according to one implementation.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It isPATENTAttorney Docket No.: 44024429WO01 contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0017] Aspects generally relate to methods, systems, and apparatus for processing substrates using one or more carbon hardmask layers. In one aspect, film stress is altered while facilitating enhanced etch selectivity.

[0018] A “substrate” as used herein, refers to any substrate or material surface formed on a substrate upon which film processing is performed during a fabrication process. For example, a substrate surface on which processing can be performed include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon doped silicon oxides, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, without limitation, semiconductor substrates. Substrates may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal and / or bake the substrate surface. In addition to film processing directly on the surface of the substrate, any of the film processing steps disclosed may also be performed on an under-layer formed on the substrate as disclosed in more detail below, and the term “substrate surface” is intended to include such under-layer as the context indicates. Thus for example, where a film / layer or partial film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0019] Implementations described herein will be described below in reference to a plasma-enhanced chemical vapor deposition (PECVD) deposition process. Any system enabling the PECVD can be used, including those from Applied Materials, Inc., of Santa Clara, Calif. The apparatus description described herein is illustrative and should not be construed or interpreted as limiting the scope of the implementations described herein.PATENTAttorney Docket No.: 44024429WO01

[0020] In semiconductor manufacturing, an oxygen-containing precursor refers to a chemical compound or gas containing oxygen atoms used in processes that involve the deposition of materials onto semiconductor substrates. These precursors are beneficial for the fabrication of various thin film layers with specific properties and functionalities in semiconductor devices. Oxygen-containing precursors play a role in processes such as oxide deposition. These oxide layers may serve as insulating layers, dielectric layers, or passivation layers in semiconductor devices. Conventional oxide layers are deposited using oxygen containing gases or plasmas, such diatomic oxygen or ozone, and cause metal gate oxidation to a certain extent.

[0021] Metal gate oxidation in semiconductor manufacturing refers to a process where a thin layer of oxide is formed on the surface of a metal gate electrode. During processing, initially, a thin layer of metal, such as titanium (Ti), tungsten (W), or a metal alloy, is deposited onto the semiconductor substrate to form the gate electrode of the transistor. This metal gate serves as a component in the transistor structure, controlling the flow of electrical current between the source and drain regions.

[0022] After the metal gate is formed, a thin layer of oxide is formed on the upper surface of the metal gate.

[0023] The formed oxide serves several purposes in semiconductor manufacturing. For example, the oxide material provides electrical insulation, preventing unwanted leakage currents and ensuring proper transistor operation. The oxide material also helps to improve the reliability and stability of the transistor by reducing interface defects and trapping charges at the gate dielectric interface.

[0024] Embodiments disclosed herein minimize or prevent metal gate oxidation by using different techniques to deposit an oxide film over an etch stop layer formed over a metal gate, thereby reducing metal gate oxidation. In one example, the oxide film is deposited as a carbon-doped oxide, such as silicon oxycarbide (SiOCH) or silicon oxide. In one example, the oxide film may be deposited using an SiOCH-containing precursor and helium (He) carrier gas. In another example, the oxide film may be deposited using an SiOCH-containing precursor with He carrier gas and hydrogen (H2) gas. In another example, the oxide film may be deposited using an SiOCH-containingPATENTAttorney Docket No.: 44024429WO01 precursor with argon (Ar) carrier gas and H2 gas. In another example, the oxide film may be deposited using an SiOCH-containing precursor and Ar carrier gas. Depositing the oxide film using one of these approaches significantly minimizes or prevents metal gate oxidation. Overall, as noted above, preventing metal gate oxidation is beneficial for ensuring the performance, reliability, and manufacturability of semiconductor devices, especially in advanced technologies where gate stack engineering plays a significant role in device characteristics. Because oxygen for the oxide film and / or etch stop layer is not provided by oxygen or ozone, but instead from another precursor, such as a silicon and / or carbon containing precursor, the oxidation of the underlying metal gate is reduced.

[0025] FIG. 1 is a schematic cross-sectional view of a chamber 100 with a pedestal 138 disposed therein, according to one implementation. The chamber 100 is for example a substrate processing chamber for fabricating semiconductors. The chamber 100 may be a deposition chamber such as a vapor deposition chamber, for example a chemical vapor deposition (CVD) chamber or a plasma enhanced CVD (PECVD) chamber. The chamber 100 has a chamber body 102 and a chamber lid 104. The chamber body 102 includes an internal volume 106 therein and a pumping path 108. The internal volume 106 is the space defined at least partially by the chamber body 102 and the chamber lid 104. The pumping path 108 is a path formed in the chamber body 102 coupled to a pumping volume 112 formed in a pumping plate 114. The pumping path 108 facilitates removal of gases from the internal volume 106.

[0026] The chamber 100 includes a gas distribution assembly 116 coupled to or disposed in the chamber lid 104 to deliver a flow of one or more gases into a processing region 110. The gas distribution assembly 116 includes a gas manifold 118 coupled to a gas inlet passage 120 formed in the chamber lid 104. The gas manifold 118 receives a flow of gases from one or more gas sources 122 (two are shown). The flow of gases received from the one or more gas sources 122 distributes across a gas box 124, flows through a plurality of openings of a backing plate 126, and further distributes across a plenum 128 defined by the backing plate 126 and a faceplate 130. The flow of gases then flows into a processing region 110 of the internal volume 106 through a plurality of openings 132 of the faceplate 130. A pump 133 is connected toPATENTAttorney Docket No.: 44024429WO01 the pumping path 108 by a conduit 134 to control the pressure within a processing region 110 and to the exhaust gases and byproducts from the processing region 110 through the pumping volume 112 and pumping path 108.

[0027] The internal volume 106 includes a pedestal 138 that supports a substrate 136 within the chamber 100. The pedestal 138 includes a heater 198 and an electrode 140 disposed within the pedestal 138. The electrode 140 may include a conductive mesh, such as a tungsten-containing, copper-containing, or molybdenum-containing conductive radio frequency (RF) mesh. The heater 198 may include any material used for heating, including an alternating current (AC) coil. FIG. 1 illustrates the heater 198 as disposed below the electrode 140. However, it is contemplated that the heater 198 may alternatively be disposed above the electrode 140.

[0028] The pedestal 138 is movably disposed in the internal volume 106 by a stem 142 coupled to a lift system. Movement of the pedestal 138 facilitates transfer of the substrate 136 to and from the internal volume 106 through a slit valve formed through the chamber body 102. The pedestal 138 may also be moved to different positions for processing, insertion, and / or removal of the substrate 136. The pedestal 138 may also have openings disposed therethrough, through which a plurality of lift pins 150 may be movably disposed. In the lowered position, the plurality of lift pins 150 are projected from the pedestal 138 by contacting a lift plate 152 coupled to a bottom 154 of the chamber body. Projection of the lift pins 150 places the substrate 136 in a spacedapart relation from the pedestal 138 to facilitate the transfer of the substrate 136.

[0029] The pedestal 138 in the implementation shown in FIG. 1 includes a support surface 138a that is configured to support a substrate 136 thereon. The support surface 138a and / or the pedestal 138 may be heated. During processing the substrate 136 is disposed on the support surface 138a. The pedestal 138 also includes an edge ring 139 disposed on the support surface 138a around the substrate 136. During substrate processing, as gases flow into the processing region 110, the heater 198 heats the pedestal 138 and the support surface 138a. Also during substrate processing, the electrode 140 propagates radio frequency (RF) energy, alternating current (AC), or direct current (DC) to facilitate plasma generation in the processing region 110 and / or to facilitate chucking of the substrate 136 to the pedestal 138. ThePATENTAttorney Docket No.: 44024429WO01 heat, gases, and energy from the electrode 140 facilitate deposition of a film onto the substrate 136 during substrate processing.

[0030] In the implementation shown, a radio frequency (RF) source 156 is coupled to the electrode 140 disposed within the pedestal 138 through a matching circuit 158. Although an RF source 156 is illustrated, the present disclosure contemplates that other power sources may be used, such as an alternating current (AC) power source or direct current (DC) power source. The matching circuit 158 is electrically coupled to the electrode 140 by a conductive rod 160. The matching circuit 158 is also electrically coupled to the heater 198. A power source 159 is configured to provide power to the heater 198. The power source 159 may provide AC power or DC power to the heater 198 to generate heat. The faceplate 130, which is grounded via coupling to the chamber body 102 and the electrode 140 facilitate formation of a capacitive plasma coupling. For example, the RF source 156 provides RF energy to the electrode 140 within the pedestal 138 to facilitate generation of a capacitive coupled plasma between the pedestal 138 and the faceplate 130 of the gas distribution assembly 116. The RF source 156 connects to ground 171. A second RF source 166 also is configured to provide RF energy to the chamber 100. The second RF source 166 is connected to ground 173. Although a second RF source 166 is illustrated, the present disclosure contemplates that other power sources may be used, such as an alternating current (AC) power source or direct current (DC) power source. In some embodiments, it is contemplated that an RF source may be coupled to the faceplate 130 to facilitate plasma generation.

[0031] When RF power is supplied to the electrode 140, an electric field is generated between the faceplate 130 and the pedestal 138 such that atoms of gases present in the processing region 110 between the pedestal 138 and the faceplate 130 are ionized and release electrons. The ionized atoms accelerate to the pedestal 138 to facilitate film formation on the substrate 136. In one example, the processing region 110 is between the faceplate 130 on a first side of the processing region 110, and the support surface 138a and the edge ring 139 on a second side of the processing region 110.PATENTAttorney Docket No.: 44024429WO01

[0032] While Figure 1 illustrates one example of a PECVD chamber for performing operations disclosed herein, it is contemplated that other chambers, including other PECVD chambers, could also be utilized. In one example, the Precision (R) PECVD chamber from Applied Materials, Inc., of Santa Clara, California, may be utilized.

[0033] Figures 2A-2D illustrate a process flow for depositing oxide films with oxygen free plasma, according to one implementation.

[0034] In Figure 2A, an etch stop layer (ESL) 204 is formed over a conductive layer 202. The conductive layer 202 can be referred to as a metal gate. The ESL 204 can have a thickness of about 20-120

[0035] In one example, which may be combined with other examples, and embodiments herein, the ESL is a SiCN or SiOCN film. The ESL may be formed directly on the upper surface of the conductive layer 202 (e.g., a metal film or metal gate). The ESL 204 is formed using an oxygen-free gas for plasma generation to reduce oxidation of the underlying conductive film 202. To facilitate nitrogen inclusion within the ESL 204, ammonia may be included with the process gases.

[0036] For deposition of the ESL 204, plasma is generated using a gas or gas mixtures in the chamber 100 with no diatomic oxygen or ozone. After the plasma is generated in the chamber 100 without oxygen, an oxygen-containing precursor is introduced. In one example, the oxygen-containing precursor may be SiOCH- containing compound. Therefore, in the instant case, oxygen within ESL 204 is provided by the SiOCH-containing compound, thus reducing metal gate oxidation, as compared to a process that uses oxygen or ozone gas.

[0037] In some examples, the stoichiometry of the deposited ESL 204 (e.g., of SiCN or SiOCN) can be affected or adjusted by composition of the plasma. For example, use of H2 and Ar to form the plasma may alter the stoichiometric ratio in the final ESL 204. In one example, inclusion of hydrogen as a carrier gas or otherwise within the plasma facilitates a reduced carbon concentration within the deposited ESL 204. In contrast, using argon rather than hydrogen is less likely to reduce carbon concentration within the ESL 204, thereby providing a greater carbon concentration relative to using hydrogen carrier gas during deposition.PATENTAttorney Docket No.: 44024429WO01

[0038] By excluding oxygen from the plasma-generating gas itself, metal gate oxidation can be prevented. Stated otherwise, any oxygen incorporated into the film is derived from the silicon and / or carbon containing precursor, rather than a separate oxygen containing gas such as oxygen, ozone, or nitrous oxide. SiOCH precursors may include, for example, ring-type precursors, linear Si-0 precursors, and built-in Si- O-Si precursors. Example SiOCH-containing precursors, include: Octamethylcyclotetrasiloxane; 2,4,6,8-Tetramethyl-2,4,6,8- tetravinylcyclotetrasiloxane; 2,4,6,8-Tetramethylcyclotetrasiloxane; Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane; Vinylmethyldimethoxysilane: Methoxytdimethvhsilylmethane: Methyl(dimethoxy)silylmethane: 1 ,3-Diethoxy-1 ,3-dimethyl-1 ,3-disilacvclobutane:1 ,1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane; and 1 ,3-Dimethyl-1 ,1 ,3,3- tetramethoxydisiloxane.

[0039]

[0040] Octamethylcyclotetrasiloxane

[0041]

[0042] 2,4,6,8-Tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxanePATENTAttorney Docket No.: 44024429WO01

[0043]

[0044] 2,4,6,8-Tetramethylcyclotetrasiloxane

[0045]

[0046] Dimethyldimethoxysilane

[0047]

[0048] Ethoxydimethylsilane

[0049]

[0050] Isobutylmethyldimethoxysilane

[0051] PATENTAttorney Docket No.: 44024429WO01

[0052] Vinylmethyldimethoxysilane

[0053]

[0054] Methoxy(dimethyl)silylmethane

[0055]

[0056] Methyl(dimethoxy)silylmethane

[0057]

[0058] 1 ,3-Diethoxy-1 ,3-dimethyl-1 ,3-disilacyclobutane

[0059]

[0060] 1 ,1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane

[0061]

[0062] 1 ,3-Dimethyl-1 , 1 ,3,3-tetramethoxydisiloxanePATENTAttorney Docket No.: 44024429WO01

[0063] The deposition temperature during formation of the ESL 204 is about 200- 400°C, the pressure is about 3-50 Torr, such as 3-10 Torr, and the RF power applied is about 150-1000 Watts. The spacing between the heater 198 and the faceplate 130 is about 200-800um. The liquid flow or flow of the SiOCH-containing containing precursor is about 100-2000 seem. The helium gas flow is about 200-5000 seem and the ammonia gas flow is about 200-5000 seem. Optionally, a hydrogen gas flow is about 50-3000 seem. The resulting film is a SiCN or SiOCN film having a carbon concentration of about 10-20 atomic percent carbon. In one example, the ESL has a thickness of 1 -10 nanometers.

[0064] In Figure 2B, an oxide layers 206A-206C is deposited over the ESL 204. The oxide layers 206A-206C can be an oxide film. The oxide film can be, e.g., a silicon dioxide (SiC ) or SiOCH. The oxide layer 206A is formed using an SiOCH-containing precursor with He carrier gas and hydrogen (H2) gas. The H2 gas is configured to reduce carbon (C) incorporate in the ESL 204 from the SiOCH-containing precursor. In another example, the oxide layer 206B is formed using an SiOCH-containing precursor with argon (Ar) carrier gas and H2 gas. In one example, the oxide layer 206C is formed using an SiOCH-containing precursor and Ar carrier gas.

[0065] The oxide layers 206A, B, C are formed using an SiOCH-containing precursor and one or more carrier gases. The SiOCH-containing precursor may be the same or different than the SiOCH precursor used for deposition of the ESL 204. However, during the deposition of the oxide layers 206A-206C the flow of ammonia is halted. This reduction in ammonia flow facilitates a reduction in carbon incorporation into the oxide layers 206A-206C relative to the ESL 204. In one example, the oxide layers 206A-206C may have a carbon concentration of 0-9 atomic %, such as 1 -3 atomic %.

[0066] An expanded section 210 depicting the three layers is shown in Figures 3A- 3C.

[0067] In some examples, the stoichiometry of the deposited SiOCH can be affected or adjusted by species in the plasma. For example, the H2 and Ar from thePATENTAttorney Docket No.: 44024429WO01 plasma may be used to alter the stoichiometric ratio in the oxide layers 206A-206C. In one example, inclusion of hydrogen as a carrier gas or otherwise within the plasma facilitates a reduced carbon concentration within the deposited oxide layers 206A- 206C. In contrast, using argon rather than hydrogen would have less-to-none carbon reduction in the deposited film.

[0068] By excluding oxygen from the plasma-generating gas itself, metal gate oxidation can be mitigated. Stated otherwise, any oxygen incorporated into the oxide layers 206A-206Cis derived from the silicon and / or carbon containing precursor (e.g., SiOCH-containing precursor), rather than a separate oxygen containing gas such as oxygen, ozone, or nitrous oxide. In other examples, the precursor can include silicon, oxygen, carbon, and hydrogen. Example SiOCH-containing precursors for deposition of the oxide layers 206A-206Cinclude: Octamethylcyclotetrasiloxane; 2,4,6,8- Tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane; _ 2, 4,6,8-Tetramethylcyclotetrasiloxane; Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane: _ Vinylmethyldimethoxysilane:Methoxy(dimethyl)silylmethane; Methyl(dimethoxy)silylmethane; 1 ,3-Diethoxy-1 ,3- dimethyl-1 ,3-disilacyclobutane; 1 , 1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane; and 1 ,3-Dimethyl-1 , 1 ,3,3-tetramethoxydisiloxane.

[0069] SiOCH-containing precursors can be delivered in a semiconductor chamber through, e.g., a vaporization process. One method includes turning the liquid precursor into a gas before the liquid enters the deposition chamber. This can be performed using a bubbler system or through a direct liquid injection system. Other deliveries are also contemplated.

[0070] SiOCH films are beneficial in semiconductor technology because SiOCH films help reduce signal delays and crosstalk between neighboring interconnect lines, thereby improving the performance and efficiency of ICs. The introduction of carbon and hydrogen atoms into the silicon dioxide (SiO2) matrix reduces the overall density of the material, resulting in a lower dielectric constant while still providing adequate insulation between conductive layers in the semiconductor device.PATENTAttorney Docket No.: 44024429WO01

[0071] In the example embodiments, SiOCH-containing precursors are used to introduce silicon, oxygen, carbon, and hydrogen atoms onto the substrate surface, allowing for the controlled formation of SiOCH films with specific properties. These precursor materials are typically organic compounds containing silicon, oxygen, and carbon functional groups, along with hydrogen atoms. During the deposition process, the SiOCH-containing precursor is introduced into the chamber 100 along with a carrier gas and, if applicable, other reactive gases. Depending on the deposition conditions and parameters such as temperature, pressure, and plasma power, the precursor undergoes chemical reactions to form a SiOCH film on the substrate surface.

[0072] The use of SiOCH-containing precursors allows semiconductor manufacturers to tailor the composition, structure, and properties of the deposited films to meet the requirements of specific applications. The use of SiOCH-containing precursors allows engineers to tailor the properties of deposited films by adjusting the precursor chemistry and process conditions. Because SiOCH films incorporate silicon, oxygen, carbon, and hydrogen in tunable ratios (for example, by selection of different SiOCH-containing precursors or by inclusion of other process gases), manufacturers can control the degree of crosslinking and the incorporation of organic groups, which directly influence the film’s density, thermal stability, and electrical insulation performance. For example, increasing carbon content can lower the dielectric constant for use in low-k interlayer dielectrics, while improving oxygen and hydrogen content can improve film adhesion and resistance to moisture uptake. This flexibility is beneficial for optimizing the electrical, mechanical, and thermal characteristics of the dielectric films used in semiconductor devices, contributing to the development of advanced integrated circuits (ICs) with improved performance and reliability. The SiOCH-containing precursor of the example embodiments is used to deposit an oxide layer 206A-206C (i.e. , SiOCH film) in combination with an ESL to minimize or prevent metal gate oxidation.

[0073] In Figure 2C, the oxide layers 206A-206C and the ESL 204 are etched to expose a top surface 201 of the conductive layer 202. An opening 220 is formed. ThePATENTAttorney Docket No.: 44024429WO01 remaining ESL is designated as ESL 204’ and the remaining oxide is designated as oxide layer 206’.

[0074] In Figure 2D, a metal fill 230 takes place. Examples of metals used for the metal fill 230 include at least copper (Cu) and tungsten (W). The metal fill 230 may be deposited using PVD or CVD. Subsequently, chemical mechanical planarization (CMP) or other planarization techniques are employed to remove excess metal and achieve a desired surface flatness.

[0075] Figures 3A-3C illustrate three techniques for using SiOCH-containing precursors, according to one implementation.

[0076] Figure 3A illustrates depositing the oxide layer 206A using an SiOCH- containing precursor and He carrier gas.

[0077] The temperature of deposition is about 200-400°C, the pressure is about 7.5-50 torr, and the RF power applied is about 300-1000 Watts. The RF frequency may be, for example, 13.56 MHz. The spacing between the substrate 136 and the faceplate 130 is about 200-800um. The liquid flow or flow of the SiOCH-containing containing precursor is about 100-2000 seem, and the helium gas flow is about 200- 5000 seem, where seem is a standard cubic centimeter per minute.

[0078] Figure 3B illustrates depositing the oxide layer 206B using an SiOCH- containing precursor with He carrier gas and H2 gas or using an SiOCH-containing precursor with Ar carrier gas and H2 gas. The inclusion of H2 gas during the deposition process is configured to reduce carbon (C) incorporation in the deposited oxide layer 206B.

[0079] The temperature of deposition is about 200-400°C, the pressure is about 7.5-50 torr, and the RF power applied is about 300-1000 Watts. The spacing between the substrate 136 and the faceplate 130 is about 200-800um. The liquid flow or flow of the oxygen containing precursor is about 100-2000 seem. The helium gas flow is about 200-5000 seem and the argon gas flow is about 200-5000 seem. The hydrogen gas flow is about 50-3000 seem.PATENTAttorney Docket No.: 44024429WO01

[0080] Figure 3C illustrates depositing the oxide layer 206C using an SiOCH- containing precursor and Ar carrier gas.

[0081] The temperature of deposition is about 200-400°C, the pressure is about 7.5-50 torr, and the RF power applied is about 300-1000 Watts. The spacing between the substrate 136 and the faceplate 130 is about 200-800um. The liquid flow or flow of the oxygen containing precursor is about 100-2000 seem, and the argon gas flow is about 200-5000 seem.

[0082] As noted above, the SiOCH-containing precursormay form a SiOCH film or an SiO2 film with 0-3 atomic percent carbon, such as 1-3 atomic percent carbon. The approaches described above enable the minimization or elimination of metal gate oxidation. Preventing metal gate oxidation in semiconductor manufacturing offers several advantages relating to maintaining electrical properties, improved reliability, enhanced process control, and reduced parasitic capacitance.

[0083] Metal gate oxidation can degrade the electrical properties of the gate material, such as increasing resistance or altering the threshold voltage. By preventing oxidation, the gate material retains its intended electrical characteristics, ensuring proper transistor operation and performance.

[0084] Oxidation of metal gates can lead to increased gate leakage currents and instability, which can compromise the reliability of the semiconductor device over time. Preventing oxidation helps maintain long-term device reliability by preserving the integrity of the gate material.

[0085] Controlling the oxidation of metal gates allows for greater consistency and repeatability in semiconductor manufacturing processes. Consistent gate properties across different devices contribute to better yield and performance uniformity.

[0086] Oxide formation on metal gates can increase the thickness of the gate dielectric, leading to higher parasitic capacitance. Minimizing oxidation helps reduce parasitic capacitance, which is essential for achieving high-speed and low-power operation in integrated circuits.PATENTAttorney Docket No.: 44024429WO01

[0087] Preventing metal gate oxidation is particularly beneficial for advanced semiconductor technologies, such as high-k metal gate (HKMG) processes used in modem complementary metal-oxide-semiconductor (CMOS) technology nodes. HKMG processes involve precise control over the gate stack to achieve optimal device performance and reliability. By eliminating the need to deal with oxide formation on metal gates, semiconductor manufacturing processes can be simplified, leading to reduced process complexity, lower manufacturing costs, and improved efficiency.

[0088] Therefore, preventing metal gate oxidation is beneficial for ensuring the performance, reliability, and manufacturability of semiconductor devices, especially in advanced technologies where gate stack engineering plays a decisive role in device characteristics. The approaches described above for depositing the oxide film advantageously enable the prevention of metal gate oxidation.

[0089] Figure 4A is a flowchart for depositing an oxide film using an SiOCH- containing containing precursor and a He carrier gas, according to one implementation.

[0090] At block 402, an ESL is formed on a conductive layer (metal film).

[0091] At block 404A, an oxide film is formed on the ESL using an SiOCH- containing precursor and He carrier gas.

[0092] At block 406, the oxide film and the ESL are etched to create an opening to a top surface of the conductive layer.

[0093] At block 408, a metal fill is deposited within the opening.

[0094] At block 410, chemical mechanical planarization (CMP) may be performed to planarized the top surface of the metal fill.

[0095] Figure 4B is a flowchart for depositing an oxide film using an SiOCH- containing precursor with a He carrier gas and H2 gas, according to one implementation.

[0096] At block 402, an ESL is formed on a conductive layer (metal film).PATENTAttorney Docket No.: 44024429WO01

[0097] At block 404B, an oxide film is formed on the ESL using an SiOCH- containing precursor with a He carrier gas and hydrogen H2 gas.

[0098] At block 406, the oxide film and the ESL are etched to create an opening to a top surface of the conductive layer.

[0099] At block 408, a metal fill is deposited within the opening.

[0100] At block 410, CMP may be performed to planarized the top surface of the metal fill.

[0101] Figure 4C is a flowchart for depositing an oxide film using an SiOCH- containing precursor with an Ar carrier gas and H2 gas, according to one implementation.

[0102] At block 402, an ESL is formed on a conductive layer (metal film).

[0103] At block 404C, an oxide film is formed on the ESL using an SiOCH- containing precursor with an Ar carrier gas and hydrogen H2 gas.

[0104] At block 406, the oxide film and the ESL are etched to create an opening to a top surface of the conductive layer.

[0105] At block 408, a metal fill is deposited within the opening.

[0106] At block 410, CMP may be performed to planarized the top surface of the metal fill.

[0107] Figure 4D is a flowchart for depositing an oxide film using an SiOCH- containing precursor and an Ar carrier gas, according to one implementation.

[0108] At block 402, an ESL is formed on a conductive layer (metal film).

[0109] At block 404D, an oxide film is formed on the ESL using an SiOCH- containing precursor and an Ar carrier gas.

[0110] At block 406, the oxide film and the ESL are etched to create an opening to a top surface of the conductive layer.PATENTAttorney Docket No.: 44024429WO01

[0111] At block 408, a metal fill is deposited within the opening.

[0112] At block 410, CMP may be performed to planarized the top surface of the metal fill.

[0113] While embodiments described herein utilize SiOCH-containing precursors, other precursors may be utilized, such as silicon or carbon-based precursors having oxygen bonded thereto.

[0114] In conclusion, as semiconductor feature sizes shrink to the nanometer scale, they approach fundamental physical limits imposed by quantum mechanics. At such small dimensions, phenomena such as quantum tunneling and leakage currents become significant challenges that can adversely affect transistor performance and reliability. Fabricating semiconductor devices at nodes below 5 nm poses significant manufacturing challenges due to the complexities of patterning, deposition, etching, and other processes. Achieving uniformity, yield, and reliability at sub-nanometer scales demands breakthroughs in process technologies, materials, and equipment. Advancing to nodes at or beyond 1 .4 nm may call for the adoption of novel materials and device structures to overcome scaling limitations. For example, alternative channel materials, such as lll-V compounds or 2D materials like graphene, may be explored to improve carrier mobility and transistor performance. Beyond traditional scaling, heterogeneous integration of diverse materials, devices, and technologies may play a pivotal role in extending semiconductor scaling beyond the 1.4 nm node. Integration of advanced packaging techniques, such as 3D stacking and chiplets, can enhance performance, functionality, and energy efficiency. The example embodiments advantageously minimize or prevent metal gate oxidation by using different techniques to deposit an oxide film over an etch stop layer formed over a metal gate. In one example, the oxide film may be deposited as a carbon-doped oxide. In one example, the oxide film may be deposited using an SiOCH-containing precursor and He carrier gas. In another example, the oxide film may be deposited using an SiOCH-containing precursor with a He carrier gas and H2 gas. In another example, the oxide film may be deposited using an SiOCH-containing precursor with Ar carrier gas and H2 gas. In another example, the oxide film may be deposited using an SiOCH-PATENTAttorney Docket No.: 44024429WO01 containing precursor and an Ar carrier gas. Depositing the oxide film using one of these approaches significantly minimizes or prevents metal gate oxidation.

[0115] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular implementations. Certain features that are described in this specification in the context of separate implementations may also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented in multiple implementations, separately, or in any suitable sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

[0116] Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed (some operations may be considered optional) to achieve desirable results. In certain circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and performed as deemed appropriate. While the various steps in an embodiment method or process are presented and described sequentially, one of ordinary skill in the art will appreciate that some or all of the steps may be executed in different order, may be combined, or omitted, and some or all of the steps may be executed in parallel. The steps may be performed actively or passively. The method or process may be repeated or expanded to support multiple components or multiple users within a field environment. Accordingly, the scope should not be considered limited to the specific arrangement of steps shown in a flowchart or diagram.PATENTAttorney Docket No.: 44024429WO01

[0117] Furthermore, any claimed implementation is considered to be applicable to at least a computer-implemented method; a non-transitory, computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and a computer system including a computer memory interoperability coupled with a hardware processor configured to perform the computer-implemented method or the instructions stored on the non-transitory, computer-readable medium.

[0118] As used herein, “a CPU”“, controller”, “a processor”, “at least one processor”, or “one or more processors”, generally refers to a single processor configured to perform one or multiple operations or multiple processors configured to collectively perform one or more operations. In the case of multiple processors, the one or more operations could be divided amongst different processors, though one processor may perform multiple operations, and multiple processors could collectively perform a single operation. Similarly, “a memory”", at least one memory”, or “one or more memories”, generally refers to a single memory configured to store data and / or instructions, multiple memories configured to collectively store data and / or instructions.

[0119] As used herein, “gas” and “fluid” may be used interchangeable with either term generally referring to elements, compounds, materials, etc., having the properties of a gas, a fluid, or both a gas and a fluid.

[0120] Unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which these systems, apparatuses, methods, processes and compositions belong.

[0121] In this disclosure, the terms “top”, “bottom”, “side”, “above”, “below”, “up”, “down”, “upward”, “downward,” “horizontal,” “vertical,” and the like do not refer to absolute directions. Instead, these terms refer to directions relative to a nonspecific plane of reference. This non-specific plane of reference may be vertical, horizontal, or other angular orientation.

[0122] The singular forms “a”, “an”, and “the”, include plural referents, unless the context clearly dictates otherwise. Within a claim, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, butPATENTAttorney Docket No.: 44024429WO01 rather “one or more”. Unless specifically stated otherwise, the term “some” refers to one or more.

[0123] Embodiments of the present disclosure may suitably “comprise”, “consist”, or “consist essentially of”, the limiting features disclosed, and may be practiced in the absence of a limiting feature not disclosed. As used here and in the appended claims, the words “comprise”, “has”, and “include”, and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

[0124] “Optional” and “optionally” means that the subsequently described material, event, or circumstance may or may not be present or occur. The description includes instances where the material, event, or circumstance occurs and instances where it does not occur.

[0125] “Coupled” and “coupling” means that the subsequently described material is connected to previously described material. The connection may be a direct, or indirect connection, and may, or may not, include intermediary components such as plumbing, wiring, fasteners, mechanical power transmission, electrical communication, wired and / or wireless transmission, etc., which may be suitable to affect operation of the components.

[0126] As used, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up, for example, looking up in a table, a database, or another data structure, and ascertaining. In addition, “determining” may include receiving, for example, receiving information, and accessing, for example, accessing data in a memory. In addition, “determining” may include resolving, selecting, choosing, and establishing.

[0127] When the word “approximately” or “about” are used, this term may mean that there may be a variance in value of up to ±10%, of up to 5%, of up to 2%, of up to 1 %, of up to 0.5%, of up to 0.1 %, or up to 0.01 %.PATENTAttorney Docket No.: 44024429WO01

[0128] Ranges may be expressed as from about one particular value to about another particular value, inclusive. When such a range is expressed, it is to be understood that another embodiment is from the one particular value to the other particular value, along with all particular values and combinations thereof within the range.

[0129] As used, terms such as “first” and “second” are arbitrarily assigned and are merely intended to differentiate between two or more components of a system, an apparatus, or a composition. It is to be understood that the words “first” and “second” serve no other purpose and are not part of the name or description of the component, nor do they necessarily define a relative location or position of the component. Furthermore, it is to be understood that that the mere use of the term “first” and “second” does not require that there be any “third” component, although that possibility is envisioned under the scope of the various embodiments described.

[0130] Although only a few example embodiments have been described in detail, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the disclosed scope as described. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus- function clauses are intended to cover the structures described as performing the recited function and not only structural equivalents, but also equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f), for any limitations of any of the claims, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.

[0131] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

PATENTAttorney Docket No.: 44024429WO01What is claimed is:1 . A method, comprising: forming an etch stop layer on a conductive layer; and depositing an oxide film on the etch stop layer using an SiOCH-containing precursor and a helium (He) carrier gas.

2. The method of claim 1 , wherein the SiOCH-containing precursor includes one or more of: Octamethylcyclotetrasiloxane; 2,4,6,8-Tetramethyl-2,4,6,8- tetravinylcyclotetrasiloxane; 2,4,6,8-Tetramethylcyclotetrasiloxane;Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane; Vinylmethyldimethoxysilane; Methoxy(dimethyl)silylmethane;Methyl(dimethoxy)silylmethane; 1 ,3-Diethoxy-1 ,3-dimethyl-1 ,3-disilacyclobutane; 1 , 1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane; and 1 ,3-Dimethyl-1 ,1 ,3,3- tetramethoxydisiloxane.

3. The method of claim 1 , wherein oxygen free plasma is used during deposition of the oxide film.

4. The method of claim 1 , wherein the etch stop layer has a thickness of 20-1205. The method of claim 1 , wherein the deposition of the oxide film occurs at a temperature in a range between 200°C and 400°C.

6. The method of claim 1 , wherein the deposition of the oxide film occurs at a pressure of 7.5 to 5 torr.

7. The method of claim 1 , wherein a flow of the He carrier gas is in a range between 200 seem and 5000 seem.

8. A method, comprising: forming an etch stop layer on a conductive layer; andPATENTAttorney Docket No.: 44024429WO01 depositing an oxide film on the etch stop layer using an SiOCH-containing precursor with a carrier gas and hydrogen (H2) gas.

9. The method of claim 8, wherein the carrier gas is helium (He).

10. The method of claim 8, wherein the carrier gas is argon (Ar).11 . The method of claim 8, wherein the SiOCH-containing precursor includes one or more of: Octamethylcyclotetrasiloxane; 2,4,6,8-Tetramethyl-2,4,6,8- tetravinylcyclotetrasiloxane; 2,4,6,8-Tetramethylcyclotetrasiloxane;Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane; Vinylmethyldimethoxysilane; Methoxy(dimethyl)silylmethane;Methyl(dimethoxy)silylmethane; 1 ,3-Diethoxy-1 ,3-dimethyl-1 ,3-disilacyclobutane;1 , 1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane; and 1 ,3-Dimethyl-1 ,1 ,3,3- tetramethoxydisiloxane.

12. The method of claim 11 , wherein oxygen free plasma is used during deposition of the oxide film.

13. The method of claim 8, wherein the deposition of the oxide film using oxygen free plasma in a chamber occurs at a temperature in a range between 200°C and 400°C.

14. The method of claim 8, wherein the deposition of the oxide film using oxygen free plasma in a chamber occurs at a pressure of 7.5 to 5 torr.

15. The method of claim 8, wherein a flow of the carrier gas is in a range between 200 seem and 5000 seem.

16. A method, comprising: forming an etch stop layer on a conductive layer; andPATENTAttorney Docket No.: 44024429WO01 depositing an oxide film on the etch stop layer using an SiOCH-containing precursor and an argon (Ar) carrier gas.

17. The method of claim 16, wherein the SiOCH-containing precursor includes one or more of: Octamethylcyclotetrasiloxane; 2,4,6,8-Tetramethyl-2,4,6,8- tetravinylcyclotetrasiloxane; 2,4,6,8-Tetramethylcyclotetrasiloxane;Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane; Vinylmethyldimethoxysilane; Methoxy(dimethyl)silylmethane;Methyl(dimethoxy)silylmethane; 1 ,3-Diethoxy-1 ,3-dimethyl-1 ,3-disilacyclobutane;1 .1.3.3-Tetramethyl-1 ,3-dimethoxydisiloxane; and 1 ,3-Dimethyl-1 ,1 ,3,3- tetramethoxydisiloxane.

18. The method of claim 17, wherein oxygen free plasma is used during deposition of the oxide film.

19. The method of claim 16, wherein the etch stop layer is deposited using anSiOCH-containing precursor, wherein the SiOCH-containing precursor for the etch stop layer deposition includes one or more of: Octamethylcyclotetrasiloxane; 2, 4,6,8- Tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane; 2, 4,6,8-Tetramethylcyclotetrasiloxane; Dimethyldimethoxysilane; Ethoxydimethylsilane; Isobutylmethyldimethoxysilane; Vinylmethyldimethoxysilane;Methoxy(dimethyl)silylmethane; Methyl(dimethoxy)silylmethane; 1 ,3-Diethoxy-1 ,3- dimethyl-1 ,3-disilacyclobutane; 1 , 1 ,3,3-Tetramethyl-1 ,3-dimethoxydisiloxane; and1 .3-Dimethyl-1 , 1 ,3,3-tetramethoxydisiloxane.

20. The method of claim 16, wherein a flow of the Ar carrier gas is in a range between 200 seem and 5000 seem.

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