Selective deposition of thin film dielectrics using surface capping chemistry

Abstract

A method of selectively depositing a film onto a first substrate surface relative to a second substrate surface. The method includes soaking a substrate surface comprising hydroxyl terminations with a silyl amine to form silyl ether terminations and depositing a film onto surfaces other than the silyl ether termination surface.

Description

[0001] This application is a divisional of the Chinese Patent Application No. 201680025233.4, filed on April 29, 2016, entitled "Selective Deposition of Thin Films Using Surface Capping Chemistry", (PCT Application No. PCT / US2016 / 030057) having a filing date of April 29, 2016. TECHNICAL FIELD

[0002] Embodiments of the present disclosure are generally directed to methods of selectively depositing films. More specifically, embodiments of the present disclosure are directed to methods of selectively depositing films using selective reduction and selective protection with alcohols. BACKGROUND

[0003] Selective deposition processes are gaining significant momentum primarily due to the need for patterned applications in semiconductors. Traditionally, patterning in the microelectronics industry has been accomplished using various photolithography and etching processes. However, as photolithography is becoming exponentially more complex and expensive, the use of selective deposition to deposit features is becoming more attractive. Another potential application of selective deposition is gap fill. In gap fill, a fill film is selectively grown from the bottom of a trench towards the top. Selective deposition can be used for other applications such as selective sidewall deposition where a film is grown on the sides of a fin. This would enable the deposition of sidewall spacers without the need for complex patterning steps.

[0004] Therefore, there is a need in the art for methods of selectively depositing a film preferentially onto one surface over different surfaces. SUMMARY

[0005] One or more embodiments of the present disclosure are directed to methods of depositing a film. A substrate is provided comprising a first substrate surface comprising a hydroxyl-terminated surface and a second substrate surface comprising a hydrogen-terminated surface. The substrate is exposed to a silyl amide to react with the hydroxyl-terminated surface to form a silyl ether-terminated surface. The substrate is exposed to one or more deposition gases to selectively deposit a film on the second substrate surface preferentially over the silyl ether-terminated surface.

[0006] Another embodiment of the present disclosure is directed to methods of depositing a film. A substrate is provided comprising a first substrate surface comprising a hydroxyl-terminated surface and a second substrate surface comprising a hydrogen-terminated dielectric. The substrate is soaked with a silyl amide to react with the hydroxyl-terminated surface to form a silyl ether-terminated surface. The substrate is exposed to one or more deposition gases to selectively deposit a silicon nitride film on the second substrate surface preferentially over the first substrate surface.

[0007] A further embodiment of the disclosure is directed to a method of depositing a film. A substrate is provided comprising a first substrate surface comprising a hydroxyl-terminated surface and a second substrate surface comprising a hydrogen-terminated dielectric. The substrate is soaked with a silyl amide to react with the hydroxyl-terminated surface to form a silyl ether-terminated surface, the silyl amide comprising one or more of 1-trimethylsilylpyrrolidine, 1-trimethylsilylpyrrole, and / or 3,5-dimethyl-l-trimethylsilylpyrazole. The substrate is exposed to one or more deposition gases to selectively deposit a silicon nitride film on the second substrate surface in preference to the first substrate surface. BRIEF DESCRIPTION OF DRAWINGS

[0008] For a more complete understanding of the features of the present disclosure, reference is now made to the detailed description of the embodiments, taken in connection with the accompanying drawings, in which:

[0009] Figure 1 schematic diagrams illustrating processing methods in accordance with one or more embodiments of the present disclosure; and

[0010] Figure 2 schematic diagrams illustrating embodiments of batch processing chambers in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0011] There are a variety of methods that can be used for selective deposition. Embodiments of the present disclosure are directed to methods that employ surface deactivation by taking advantage of the surface chemistry of two different surfaces. Since the two different surfaces will have different reactive operations, the difference can be exploited by using molecules that will react with one surface (to deactivate that surface) and not the other. Some embodiments of the present disclosure use the chemical properties of trimethylsilyl amides to react with Si-OH groups of one surface and not react with the Si-H terminated second surface.

[0012] The terms "substrate" and "wafer" are used interchangeably in this specification and the appended claims, both refer to a surface, or a portion of a surface, on which processing acts. Those skilled in the art will also appreciate that reference to a substrate can also refer to only a portion of a substrate, unless the context clearly indicates otherwise. Additionally, reference to depositing on a substrate can mean both a bare substrate and a substrate with one or more films or features deposited or formed thereon.

[0013] As used herein, "substrate" 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 dioxide, strained silicon, silicon on insulator (SOI), carbon doped silicon oxides, silicon nitride, 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 wafers. Substrates can 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 itself, any of the film processing steps disclosed can also be performed on an underlayer formed on the substrate as disclosed in more detail below, and the term "substrate surface" is intended to include such underlayer as the context indicates. Thus, for example, where film / layer or partial film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes a substrate surface. What a given substrate surface comprises will depend on what film is to be deposited, and the particular chemistry used. In one or more embodiments, a first substrate surface will comprise a metal, and a second substrate surface will comprise a dielectric, or vice versa. In some embodiments, a substrate surface can comprise certain functional groups (e.g., -OH, -NH, etc.).

[0014] Likewise, films that can be used in the methods described herein are quite varied. In some embodiments, the film can comprise, or consist essentially of, a metal. Examples of metal films include, but are not limited to, cobalt (Co), copper (Cu), nickel (Ni), tungsten (W), etc. In some embodiments, the film comprises a dielectric. Examples include SiO2, SiN, HfO2, etc.

[0015] The terms "reactant gas," "precursor," "reactant," and the like are used interchangeably in this specification and the appended claims to refer to a gas that includes a species that reacts with a substrate surface. For example, a first "reactant gas" can simply adsorb onto the surface of a substrate and can be used in further chemical reactions with a second reactant gas.

[0016] Embodiments of the present disclosure provide methods of selectively depositing a metal film on one surface over a second surface. As used in this specification and the appended claims, the phrase "selectively depositing a film on one surface over another surface" and similar phrases means that a first amount of the film is deposited on the first surface and a second amount of the film is deposited on the second surface, where the second amount of the film is less than the first amount of the film or none. The use of the word "over" in this regard does not imply a physical orientation of one surface on top of another surface, but rather a relationship of the thermodynamics or kinetics of the chemical reaction of one surface relative to another surface. For example, selectively depositing a cobalt film on a copper surface over a dielectric surface means that the cobalt film is deposited on the copper surface and less or no cobalt film is deposited on the dielectric surface; or that the formation of the cobalt film on the copper surface is thermodynamically or kinetically favored over the formation of the cobalt film on the dielectric surface.

[0017] Referring to Figure 1 One or more embodiments of the present disclosure are directed to methods of depositing a film. A substrate 10 is provided that includes a first substrate surface 12 and a second substrate surface 14. The first substrate surface 12 includes a hydroxyl-terminated surface (i.e., a surface having -OH groups). The second substrate surface 14 includes a hydrogen-terminated surface (i.e., a surface having -H end groups such as Si-H or Si-NH2). The hydrogen-terminated surface can include an amine-terminated surface (as can be found in SiN films). In some embodiments, the first substrate surface 12 includes substantially only hydroxyl end groups. As used in this regard, the phrase "substantially only" means that at least about 75%, 80%, 85%, 90%, or 95% of the surface end groups of the first substrate surface are hydroxyl end groups. In some embodiments, the second substrate surface 14 includes substantially only hydrogen end groups. As used in this regard, the phrase "substantially only" means that at least about 75%, 80%, 85%, 90%, or 95% of the surface end groups of the second substrate surface are hydrogen end groups. In some embodiments, one or more of the first substrate surface 12 and the second substrate surface 14 include a dielectric. In one or more embodiments, the first substrate surface 12 includes a dielectric. The dielectric can be a low-k dielectric or a high-k dielectric.

[0018] The substrate 10 is exposed to a silyl amide to react with one or more of the first substrate surface 12 and / or the second substrate surface 14. Exposing the substrate surface to the silyl amide can be accomplished by any appropriate process. The exposure can be referred to as a soak, where at least some of the substrate surface is "soaked" or "flooded" with the silyl amide to allow the surface reaction to occur. As used in this specification and the appended claims, the term "silyl amide" refers to a compound having a silicon-nitrogen bond, where the nitrogen is part of an amine group or part of a heterocycle. Figure 1A schematic of the initial surface reaction occurring on a Si-OH terminated surface (first substrate surface 12) is shown in contrast to that occurring on a Si-H terminated surface (second substrate surface 14).

[0019] The silicon-carbon bond is very strong and not very reactive. Without being bound by any particular theory of operation, it is believed that silylamides can deactivate any surface through the silicon-carbon bond. The silicon-carbon bond is also thermally stable, exhibiting stability up to 600°C. The silylamide group is not reactive toward basic Si-H groups and will not deactivate Si-H terminated surfaces. It has been found that the use of silylamides can allow for the selective deposition of certain dielectric processes on Si-H terminated surfaces and not on Si-OH terminated surfaces.

[0020] Figure 1 The silylamide in Formula (I) is represented by (CH3)3Si-L, where L is any amine or heterocyclic amine. Figure 1 The silylamide shown is merely one possible silylamide and should not be considered limiting of the scope of the disclosure. The silylamide reacts with the hydroxyl end groups on the first substrate surface 12 to form a silyl ether terminated surface 13 and to form HL stepwise. The term "silyl ether" as used in this specification and the appended claims refers to a compound having a Si-O bond that forms a surface end group.

[0021] Suitable silylamides are those that can react with surface hydroxyl groups to form a silyl ether terminated surface. In some embodiments, the silylamide comprises an organosilylamide. The term "organosilylamide" as used in this specification and the appended claims refers to a compound in which a silicon atom is bonded to one or more organic groups. For example, as shown in Formula (II), the organosilylamide is a trimethylsilylamide. Figure 1

[0022] In one or more embodiments, the organosilylamide comprises a silicon atom that is bonded substantially only to carbon and / or nitrogen atoms. The term "substantially only to carbon and / or nitrogen" as used in this specification and the appended claims means that less than about 5% of the silicon atoms are bonded to atoms other than carbon or nitrogen on an atomic basis. In one or more embodiments, the organosilylamide is substantially free of Si-H or Si-OH bonds. The term "substantially free of Si-H and / or Si-OH bonds" as used in this specification and the appended claims means that less than about 5% of the silicon atoms are bonded to hydrogen or hydroxide.

[0023] ​In some embodiments, the organosilylamides include one or more of trimethylsilylamide, triethylsilylamide, ethyldimethylsilylamide, and / or diethylmethylsilylamide. In one or more embodiments, the silylamides include amides that include one or more of pyrrolidine, pyrrole, pyrazole, dimethylamine, diethylamine, ethylmethylamine, cyclic secondary amines, saturated cyclic amines, and / or unsaturated cyclic amines.

[0024] Trimethylsilylamides contain basic amine groups that will readily react with Si-OH groups to form free amines and result in the formation of very stable (CH3)3Si-O-Si moieties. In certain embodiments, the silylamides include one or more of 1- trimethylsilylpyrrolidine, 1-trimethylsilylpyrrole, and / or 3,5-dimethyl-1- trimethylsilylpyrazole.

[0025] The temperature at which the pretreatment (i.e., silylamide) is exposed to the substrate surface depends on, for example, the first surface, the second surface, the silylamide, planned future processing, past processing, and the processing equipment being used. For example, lower temperature processes can help preserve the thermal budget of the substrate for further processing. In some embodiments, the substrate surface is exposed to the silylamide at a temperature in a range from about 50 °C to about 600 °C.

[0026] The exposure time of the silylamide can vary depending on, for example, the reactivity of the silylamide to the target surface material. In some embodiments, the substrate is exposed to the silylamide for a time in a range from about 10 seconds to about 60 minutes. In some embodiments, the exposure of the silylamide occurs for a time of less than about 10 minutes, 5 minutes, 1 minute, or 0.5 minutes.

[0027] After forming the silyl ether terminated surface 13, a film can be deposited onto the second substrate surface 14 without affecting the silyl ether terminated surface 13. The film can be deposited by any appropriate technique. In some embodiments, the substrate 10 is exposed to one or more deposition gases to selectively deposit a film 15 on the second substrate surface 14 over the silyl ether terminated surface 13. In one or more embodiments, the deposited film 15 includes SiN. The film 15 of some embodiments is deposited by atomic layer deposition, which includes sequential exposure to a silicon-containing gas and a nitrogen-containing gas. Suitable silicon-containing gases include, but are not limited to, silane, disilane, propylsilane, monochlorosilane, dichlorosilane, trichlorosilane, silicon tetrachloride, hexachlorodisilane (HCDS), halogenated carbosilanes, and combinations of the foregoing. Suitable nitrogen-containing gases include, but are not limited to, nitrogen-containing plasmas, ammonia, amines, hydrazines, and / or carbon nitrides.

[0028] The film formation process can be a CVD process in which the first and second reactant gases are simultaneously exposed to the substrate surface such that the first and second reactant gases mix during the formation of the film.

[0029] In some embodiments, the film formation process is an ALD process in which the substrate or portion of the substrate is sequentially exposed to the first and second reactant gases. Sequentially exposed means that at any given time the substrate or portion of the substrate is only exposed to one of the first and second reactant gases. In an ALD process, there is substantially no gas phase mixing of the first and second reactant gases.

[0030] Figure 2 An embodiment of a spatial atomic layer deposition batch processor, referred to as a process chamber 110, is illustrated. The shape and components of the process chamber 110 described are exemplary only and should not be considered limiting of the scope of the disclosure. For example, the octagonal process chamber can be circular or hexagonal, etc. A load lock 112 chamber is connected to a front portion (which can be arbitrarily designated as the front portion) of the process chamber 110 and provides a means of isolating the interior of the process chamber from the atmosphere outside of the process chamber 110. The load lock 112 can be any suitable load lock and can operate in any suitable manner known to those skilled in the art.

[0031] The substrate 160 is transferred into the process chamber 110 into a loading zone 120. In the loading zone 120, the substrate 160 can be subjected to a processing condition or can be left undisturbed. The processing condition in the loading zone can be, for example, preheating the substrate 160 to a processing temperature, exposure to a pre-treatment (such as silylamine exposure), or cleaning. In some embodiments, the substrate 160 is exposed to a pre-treatment comprising a gaseous silylamine.

[0032] The substrate 160 is moved laterally from the loading zone through a gas curtain 140 to a first processing region 121. The use of numerals to describe the processing regions is exemplary only and should not be considered limiting of the scope of the disclosure. The use of the terms "first processing region," "second processing region," etc. is intended only as a convenient way to describe different portions of the process chamber. The specific location of the processing regions within the chamber is not limited to the illustrated embodiment. The lateral movement of the substrate 160 can occur by rotating the susceptor 166 about the axis indicated by arrow 117, or in the opposite direction of arrow 117. In the first processing region 121, the substrate 160 can be exposed to a first reactant gas or precursor for performing an ALD process.

[0033] The substrate 160 is moved laterally within the processing chamber 110 from the first processing region 121 through the gas curtain 140 to the second processing region 122. The gas curtain 140 provides a separation between the various processing regions within the processing chamber 110. The gas curtain is illustrated as a wedge shaped member with a truncated inner end, but it will be understood that the gas curtain can be any shape suitable for keeping the processing regions isolated. The gas curtain 140 can include any suitable combination of inert gas and / or vacuum ports capable of separating the atmosphere of the various processing regions. In some embodiments, the gas curtain 140 contains a vacuum port, an inert gas port, and another vacuum port in that order. At some point during the movement of the substrate from the first processing region 121 to the second processing region 122, one portion of the substrate is exposed to the second processing region while another portion of the substrate is exposed to the first processing region 121, and a central portion is within the gas curtain 140.

[0034] Once in the second processing region 122, the substrate 160 can be exposed to a second reactant gas that can complete the ALD process. For example, if a SiN film is being formed, the first reactant gas can be a silicon containing precursor and the second reactant gas can be a nitrogen containing gas.

[0035] The substrate 160 can be continuously moved laterally along the circular path indicated by arrow 117 to expose the substrate to the third processing region 123, the fourth processing region 124, the fifth processing region 125, the sixth processing region 126, and the seventh processing region 127 and back to the load zone. In some embodiments, the load zone 120, the second processing region 122, the fourth processing region 124, and the sixth processing region 126 each expose the substrate to a second reactant gas that includes an alcohol, and the first processing region 121, the third processing region 123, the fifth processing region 125, and the seventh processing region 127 each expose the substrate 160 to a first reactant gas. Figure 2 The illustrated embodiment has wedge shaped gas distribution assemblies 130 located over the first, third, fifth, and seventh processing regions, with the substrate 160 on the pedestal 166 shown between the gas distribution assemblies 130 for clarity. However, it will be understood that any or all of the processing regions can have gas distribution assemblies 130 or other gas distribution systems.

[0036] Once the film 15 has been deposited, further processing can be performed. For example, deprotection of the first substrate surface 12 can be performed to remove the silyl ether end groups. This can be done after deposition of the film 15 by any suitable method or technique that can remove the silyl ether end groups from the surface. Further processing can be performed in the same processing chamber or a different processing chamber.

[0037] In some embodiments, the ALD deposition cycles follow the silyl amine exposure. At some time interval, the silyl ether is etched and a new silyl ether layer is formed. In some embodiments, the silyl ether is etched after no more than about 300 ALD cycles, or 200 ALD cycles, or 100 ALD cycles, or 75 ALD cycles, or 50 ALD cycles. In one or more embodiments, an etch process is performed after every 100 ALD deposition cycles, after which the substrate is again treated with silyl amine prior to continuous deposition.

[0038] In some embodiments, the process is performed in a batch processing chamber. For example, in a spin-rack chamber, in which one or more wafers are placed on a rotating holder ("racks"). As the racks rotate, the wafers move between various processing zones. For example, in ALD, the processing zones expose the wafers to precursors and reactants. In addition, plasma exposure can be used to appropriately treat the film or surface to enhance growth of the film, or to obtain desired film properties.

[0039] Some embodiments of the present disclosure process a substrate having a first surface and a second surface in a single processing chamber, in which the substrate surface is exposed to a silyl amine in a first portion of the chamber. The substrate can then be rotated to a second portion of the processing chamber, and / or a subsequent portion of the processing chamber for deposition of a film. In some embodiments, the substrate can be further rotated or moved to another portion of the processing chamber that can remove silyl ether end groups. To separate each or any portion, or zone, of the processing chamber, a gas curtain can be employed. The gas curtain provides one or more of a purge gas and a vacuum port between processing zones to prevent the movement of reactive gases from one zone to an adjacent zone. In some embodiments, the substrate is simultaneously exposed to more than one processing zone, and one portion of the substrate is in a first zone (e.g., for silyl amine exposure) and simultaneously another portion of the substrate is in a separate zone of the processing chamber.

[0040] Embodiments of the disclosure can be used with linear processing systems or rotational processing systems. In linear processing systems, the width of the region where plasma exits the chamber is approximately the same across the entire length of the front face. In rotational processing systems, the chamber can be generally "doughnut-shaped" or "wedge-shaped." In a wedge-shaped section, the width of the region where plasma exits the chamber changes to conform to the doughnut shape. The terms "doughnut-shaped" and "wedge-shaped" are used interchangeably in this specification and the appended claims to describe a generally circular sector-shaped body. For example, a wedge-shaped section can be a small portion of a circular or disc-shaped object and can have a cut-off point. The inner edge of a doughnut-shaped section can come to a point or can be cut off to a flat edge or a circle. The path of the substrate can be perpendicular to the gas inlets. In some embodiments, each gas injector assembly includes a plurality of elongated gas inlets extending in a direction generally perpendicular to the path of motion of the substrate. The term "generally perpendicular" as used in this specification and the appended claims means that the general direction of movement of the substrate is along a plane that is approximately perpendicular (e.g., about 45° to 90°) to the axis of the gas inlets. For wedge-shaped gas inlets, the axis of the gas inlets can be considered to be the line defined by the midpoint of the gas inlet width extending along the length of the gas inlets.

[0041] Other embodiments of the disclosure are directed to methods of processing a plurality of substrates. The plurality of substrates are loaded onto a substrate support in a processing chamber. The substrate support is rotated to pass each of the plurality of substrates across a gas distribution assembly, exposing a substrate surface to silylamine, depositing a film on the substrate, and optionally removing a silyl ether layer.

[0042] The rotation of the rotary rack can be continuous or discontinuous. In continuous processing, the wafer is continuously rotated so that the wafer is sequentially exposed to each injector. In discontinuous processing, the wafer can be moved to an injector region and stopped, then moved to a region between injectors and stopped. For example, the rotary rack can be rotated so that the wafer moves from an inter-injector region through an injector (or stops adjacent to an injector) and onto the next inter-injector region, where the rotary rack can again be paused. The pause between injectors can provide time for additional processing (e.g., exposure to plasma) between each layer deposition. The frequency of the plasma can be adjusted depending on the particular reactant species being used. Suitable frequencies include, but are not limited to, 400 kHz, 2 MHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, and 100 MHz.

[0043] According to one or more embodiments, the substrate is processed before and / or after the formation of the layer. This processing can be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from a first chamber to a separate second chamber for further processing. The substrate can be moved directly from the first chamber to the separate processing chamber, or the substrate can be moved from the first chamber to one or more transfer chambers and then to the separate processing chamber. Thus, the processing apparatus can include multiple chambers in communication with transfer stations. This type of apparatus may be referred to as a "clustering tool" or "clustering system," and the like.

[0044] Generally, a clustering tool is a modular system comprising multiple chambers that perform various functions, including substrate centering and orientation, degassing, annealing, deposition, and / or etching. According to one or more embodiments, the clustering tool includes at least a first chamber and a central transfer chamber. The central transfer chamber may house a robot capable of moving the substrate back and forth between a processing chamber and a loading lock chamber. The transfer chamber is typically maintained under vacuum and provides intermediate stages for moving the substrate back and forth from one chamber to another and / or to a loading lock chamber positioned at the front end of the clustering tool. Two well-known clustering tools applicable to this disclosure are... and All are available from Applied Materials, Inc., of Santa Clara, California, USA. Details of such a staged vacuum substrate processing apparatus are disclosed in U.S. Patent No. 5,186,718 to Tepman et al., entitled “Staged-Vacuum Wafer Processing Apparatus and Method,” published February 16, 1993. However, the exact arrangement and combination of the chambers can be varied for the purpose of performing the specific steps of the processes described herein. Other processing chambers that can be used include, but are not limited to, cyclic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, chemical cleaning, thermal treatment such as RTP, plasma nitriding, degassing, orientation, hydroxylation, and other substrate processes. By performing the process in a chamber on a cluster tool, surface contaminants of atmospheric impurities on the substrate can be avoided without oxidation before the deposition of subsequent films.

[0045] According to one or more embodiments, the substrate is continuously under vacuum or "load lock" conditions and is not exposed to ambient air when being moved from one chamber to the next. The transfer chamber is thus under vacuum and is "pumped down" under vacuum pressure. Inert gas can be present in the processing chamber or the transfer chamber. In some embodiments, the inert gas is used as a purge gas to remove some or all of the reactants after a layer is formed on the surface of the substrate. According to one or more embodiments, purge gas is injected at the exit of the deposition chamber to prevent reactants from moving from the deposition chamber to the transfer chamber and / or other processing chambers. Thus, the flow of inert gas forms a curtain at the exit of the chamber.

[0046] During processing, the substrate can be heated or cooled. This heating or cooling can be accomplished by any suitable means including, but not limited to, changing the temperature of the substrate support (e.g., pedestal) and flowing heated or cooled gas to the substrate surface. In some embodiments, the substrate support includes a heater / cooler that can be controlled to change the temperature of the substrate conductively. In one or more embodiments, the gas being employed (either a reactive gas or an inert gas) is heated or cooled to change the temperature of the substrate locally. In some embodiments, a heater / cooler is positioned within the chamber proximate to the substrate surface to change the temperature of the substrate convectively.

[0047] The substrate can also be stationary or rotated during processing. A rotated substrate can be rotated continuously or rotated in discrete steps. For example, the substrate can be rotated throughout the entire process from start to finish, or the substrate can be rotated a small amount between exposures to different reactive or purge gases. Rotating the substrate during processing (either continuously or in steps) can help produce a more uniform deposition or etch by minimizing the effects of local variations in, for example, gas flow geometry.

[0048] Preparation of trimethylsilyl amide

[0049] One way to prepare trimethylsilyl amide compounds is by salt displacement of a lithium amide using trimethylsilyl chloride. The reaction scheme is illustrated in Equation 1,

[0050]

[0051] where L can equal any amine or heterocyclic amine. Some specific examples of amines are dimethylamine, diethylamine, pyrrolidine, pyrazole, and pyrrole.

[0052] Synthesis of 1-trimethylsilyl pyrrolidine

[0053] Equation 2 shows the synthetic scheme for 1-trimethylsilylpyrrolidine, referred to as BL1. 6.5 mL (80 mmol) of pyrrolidine was dissolved in 250 mL of hexane, and the solution was cooled to -78 °C. 50 mL (80 mmol) of 1.6 M n-butyllithium in hexane was added dropwise to this solution over a 15-minute period. The resulting reaction mixture was allowed to slowly reach room temperature and stirred for 30 minutes. The reaction mixture was then cooled again to -78 °C, and 20 mL of a hexane solution containing 10.1 mL (80 mmol) of trimethylsilyl chloride was added over a 10-minute period. The reaction mixture was allowed to slowly reach room temperature and stirred for 12 hours. A white precipitate was filtered off under an inert atmosphere, and the hexane was evaporated under vacuum. The product was distilled to a colorless liquid at 110 °C and 760 Torr. Yield: 8.9 g (77.5%). 1 HNMR(400.18MHz,C6D6)2.87(m,4H),1.57(m,4H),0.11(s,9H)ppm; 13 CNMR(100.64MHz,C6D6)1.08ppm.

[0054]

[0055] Synthesis of 1-trimethylsilylpyrrole

[0056] Equation 3 shows the synthetic scheme for 1-trimethylsilylpyrrole, also known as BL2. First, 5.55 mL (80 mmol) of pyrrole was dissolved in 250 mL of hexane, and the solution was cooled to -78 °C. Over a period of 15 minutes, 50 mL (80 mmol) of 1.6 M n-butyllithium in hexane was added dropwise to this solution. The resulting reaction mixture was allowed to slowly reach room temperature and stirred for 30 minutes. The reaction mixture was then cooled again to -78 °C, and over a period of 10 minutes, 10.1 mL (80 mmol) of a 20 mL hexane solution of trimethylsilyl chloride was added. The reaction mixture was allowed to slowly reach room temperature and stirred for 12 hours. A white precipitate was filtered off under an inert atmosphere, and the hexane was evaporated under vacuum. The product was distilled at 130 °C and 760 Torr to obtain a colorless liquid. Yield: 8.7 g (78.2%). 1 HNMR(400.18MHz,C6D6)6.74(s,2H),6.54(s,2H),0.07(s,9H)ppm; 13 CNMR (100.64 MHz, C6D6) 123.47, 112.20, -0.01 ppm. Mass spectrometer: Calculation [M+H] + =140.1 m / Z, found to be 140.2.

[0057]

[0058] Synthesis of 3,5-dimethyl-l-trimethylsilylpyrazole

[0059] Equation 4 shows a synthesis scheme for 3,5-dimethyl-l-trimethylsilylpyrazole, also known as BL3. 7.7 g (80 mmol) of 3,5-dimethylpyrazole was dissolved in 250 mL of hexanes and the solution was cooled to -78 °C. 50 mL (80 mmol) of 1.6 M n-butyllithium in hexanes was added dropwise to this solution over a 15 minute period. The resulting reaction mixture was allowed to slowly reach room temperature and stirred for 30 minutes. The reaction mixture was then cooled again to -78 °C and a 20 mL hexanes solution of 10.1 mL (80 mmol) trimethylsilyl chloride was added over a 10 minute period. The reaction mixture was allowed to slowly reach room temperature and stirred for 12 hours. The white precipitate was filtered off under an inert atmosphere and the hexanes were evaporated under vacuum. The product was distilled as a colorless liquid at 70 °C, 20 Torr. Yield: 9.4 g (70.0%). 1 HNMR (400.18 MHz, C6D6) 5.80 (S, 1H), 2.30 (S, 3H), 2.00 (s, 3H), 0.32 (s, 9H) ppm; 13 CNMR (100.64 MHz, C6D6) 151.97, 146.04, 108.40, 32.54, 23.63, 1.02 ppm.

[0060]

[0061] According to 1 HNMR and 13 CNMR, the synthesis preparation, characterization, and properties exhibited good purity and high yield. According to TGA analysis, these molecules are volatile (with a maximum evaporation rate between 90-137 °C) and thermally stable with ~0% residue.

[0062] Examples

[0063] Trimethylsilyl amide was tested as a capping layer by treating substrates (Si(H), SiO2 1K, Si(native oxide)) in the vapor phase at 350 °C using BL1. ALD of SiN was then performed at the same temperature. The silicon precursor used was silicon tetrabromide and the nitrogen containing precursor included ammonia (30T). There were a total of 100 cycles. Table 1 shows the results of using BL1 soak for different lengths of time at 2.4 Torr. Table 2 shows the results of a 30 second soak at 5 Torr.

[0064] Table 1

[0065]

[0066] Table 2

[0067]

[0068] When no pre-treatment with BL1 is used, very low selectivity relative to Si(H), Si02 1K, and Si(natural O) is observed. BL1 soak times of over 1 minute at 2T can have very good selectivity. Based on contact angle measurements, there is little or no SiN deposition on Si02 and silicon (natural O) substrates. This can be verified by the hydrophilicity on Si(H) versus the hydrophobicity on Si02 and silicon (natural O). At a BL1 soak time of 30 seconds, there is still some selectivity based on Ellipsometry, however the contact angles are very similar, which can indicate SiN on all three surfaces. Increasing the pressure to 5T for 30 seconds can restore selectivity.

[0069] The selectivity of BL1 as a function of cycle number was also evaluated. The results are collected in Table 3. After 100 cycles, a selectivity of ~8.6 (Si(H) vs Si02) is observed. The selectivity exhibits a decrease after 100 cycles. Without being bound by any particular theory of operation, it is believed that the BL1 passivation layer can facilitate a nucleation delay that lasts for approximately 100 cycles.

[0070] Table 3

[0071]

[0072] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure can be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method of depositing a film, the method comprising the steps of: exposing a substrate comprising a first substrate surface having a hydroxyl-terminated surface and a second substrate surface having a hydrogen-terminated surface to a silyl amide to react with the hydroxyl-terminated surface to form a silyl ether-terminated surface, one or more of the first substrate surface and the second substrate surface comprising a dielectric; selectively forming a film on the second substrate surface in preference to the first substrate surface by exposing the substrate to one or more deposition gases; and etching the silyl ether-terminated surface after a predetermined amount of film is formed on the second substrate surface, after which the substrate is again exposed to a silyl amide to again form the silyl ether-terminated surface and additional film formation.

2. The method of claim 1, wherein the silyl amide comprises an organosilyl amide.

3. The method of claim 2, wherein the organosilyl amide comprises silicon atoms bonded only to carbon and / or nitrogen atoms.

4. The method of claim 2, wherein the organosilyl amide is free of Si-H or Si-OH bonds.

5. The method of claim 2, wherein the organosilyl amide comprises one or more of trimethylsilyl amide, triethylsilyl amide, ethyldimethylsilyl amide, and / or diethylmethylsilyl amide.

6. The method of claim 1, wherein the silyl amide has a silicon-nitrogen bond, wherein the nitrogen is part of an amine group, wherein the amine group comprises one or more of dimethylamine, diethylamine, ethylmethylamine, a cyclic secondary amine, a saturated cyclic amine, and / or an unsaturated cyclic amine.

7. The method of claim 1, wherein the silyl amide has a silicon-nitrogen bond, wherein the nitrogen is part of a heterocycle, wherein the heterocycle comprises one or more of pyrrolidine, pyrrole, and / or pyrazole.

8. The method of claim 1, wherein the silyl amide comprises one or more of 1- trimethylsilylpyrrolidine, 1-trimethylsilylpyrrole, and / or 3,5-dimethyl-1- trimethylsilylpyrazole.

9. The method of claim 1, wherein the first substrate surface comprises a dielectric.

10. The method of claim 1, wherein the silyl ether-terminated surface is etched and reformed after no more than 300 atomic layer deposition cycles.

11. The method of claim 1, wherein the substrate is exposed to the silyl amide for a time in the range of 10 seconds to 60 minutes.

12. The method of claim 1, wherein the film comprises SiN.

13. The method of claim 12, wherein the film is deposited by atomic layer deposition comprising sequential exposure to a silicon-containing gas and a nitrogen-containing gas.

14. The method of claim 13, wherein the silicon-containing gas comprises silane.

15. The method of claim 14, wherein the silane is disilane, trisilane, monochlorosilane, dichlorosilane, trichlorosilane, silicon tetrachloride, hexachlorodisilane (HCDS), or halocarbylsilane.

16. The method of claim 13, wherein the nitrogen-containing gas comprises one or more of a nitrogen-containing plasma, ammonia, an amine, a hydrazine, and / or a carbon nitride.

17. A method of depositing a film, the method comprising the steps of: providing a substrate comprising a first substrate surface having a hydroxyl-terminated surface and a second substrate surface having a hydrogen-terminated surface, one or more of the first substrate surface and the second substrate surface comprising a dielectric; immersing the hydroxyl-terminated surface of the first substrate surface in a silyl amide to form a silyl ether-terminated surface; and selectively depositing a silicon nitride film on the second substrate surface over the first substrate surface by an atomic layer deposition process in which the substrate is sequentially exposed to a silicon-containing gas and a nitrogen-containing gas.

18. The method of claim 17, wherein the silyl amide comprises silicon atoms bonded only to carbon and / or nitrogen atoms and no Si-H or Si-OH bonds, and the silyl amide has a silicon-nitrogen bond in which the nitrogen is part of an amine group, wherein the amine group comprises one or more of dimethylamine, diethylamine, ethylmethylamine, a cyclic secondary amine, a saturated cyclic amine, and / or an unsaturated cyclic amine.

19. The method of claim 17, wherein the silyl amide comprises silicon atoms bonded only to carbon and / or nitrogen atoms and no Si-H or Si-OH bonds, and the silyl amide has a silicon-nitrogen bond in which the nitrogen is part of a heterocycle, wherein the heterocycle comprises one or more of pyrrolidine, pyrrole, and / or pyrazole.

20. The method of claim 19, wherein the silyl amide comprises one or more of 1- trimethylsilylpyrrolidine, 1-trimethylsilylpyrrole, and / or 3,5-dimethyl-1- trimethylsilylpyrazole.

21. The method of claim 17, wherein the silicon-containing gas comprises a silane.

22. The method of claim 21, wherein the silane is disilane, trisilane, monochlorosilane, dichlorosilane, trichlorosilane, silicon tetrachloride, hexachlorodisilane (HCDS), or halocarbylsilane.

23. A method of depositing a film, the method comprising the steps of: providing a substrate comprising a first substrate surface comprising a hydroxyl-terminated surface and a second substrate surface comprising a hydrogen-terminated surface, one or more of the first substrate surface and the second substrate surface comprising a dielectric; Submerging substrates including a hydroxyl-terminated first substrate surface and a hydrogen-terminated second substrate surface with a silyl amide to react with the hydroxyl-terminated first substrate surface to form a silyl ether-terminated surface, the silyl amide including one or more of 1-trimethylsilylpyrrolidine, 1-trimethylsilylpyrrole, or 3,5-dimethyl-1-trimethylsilylpyrazole; and forming a silicon nitride film selectively on the second substrate surface over the first substrate surface by sequentially exposing the substrate to a silicon-containing gas in a first processing region, laterally moving the substrate through a gas curtain to a second processing region, and exposing the substrate to a nitrogen-containing gas in the second processing region.

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