Methods and systems for cleaning high aspect ratio structures

Abstract

Embodiments of this disclosure generally relate to methods and systems for cleaning substrate surfaces. In one embodiment, a method for processing a substrate is provided. This method includes introducing the substrate into a processing space of a processing chamber by positioning the substrate on a substrate support. The method further includes flowing a first processing gas, comprising HF, flowing a second processing gas, comprising pyridine, pyrrole, aniline, or a combination thereof, into the processing space, and exposing the substrate to the first and second processing gases to remove oxides from the substrate under oxide removal conditions. In another embodiment, a system is provided including a processing chamber for processing a substrate and a controller for causing the processing method to be performed within the processing chamber.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to methods and systems for cleaning substrate surfaces. Background Technology

[0002] When exposed to typical substrate manufacturing equipment environmental conditions, the surfaces of monocrystalline silicon and epitaxial silicon are susceptible to contamination. For example, due to substrate handling and / or exposure to the surrounding environment within the substrate processing equipment, a native oxide layer can form on the monocrystalline silicon surface prior to epitaxial layer deposition. Furthermore, foreign contaminants present in the surrounding environment, such as carbon and oxygen species, can deposit on the monocrystalline surface. The presence of a native oxide layer and / or contaminants on the monocrystalline silicon surface negatively impacts the quality of the epitaxial layer subsequently formed on the monocrystalline surface. Therefore, pre-cleaning the substrate is desirable to remove surface oxides and other contaminants before growing epitaxial layers on the substrate.

[0003] Removing native oxides from the silicon surface at the bottom of high aspect ratio device features is challenging, at least because reactants must reach the bottom of the feature to clean it. That is, oxide removal becomes more difficult as the aspect ratio of the feature increases and the openings become smaller. Furthermore, the depth to which oxide removal can be achieved is limited, for example, by bottlenecks, where the bottom pinch-off of the trench and aspect ratio-dependent oxide removal decrease significantly with increasing aspect ratio or depth. For example, conventional dry cleaning processes using, for example, HF / NH3 or NF3 / NH3 form salts in the feature during the cleaning process. These salts pinch off the bottom of the trench, thus limiting the ability of reactants to reach the bottom of high aspect ratio features. To mitigate the salt pinch-off in the tighter openings of high aspect ratio features, conventional methods include annealing operations to remove the salts—that is, conventional methods utilize multiple cycles of salt formation and annealing, resulting in low manufacturing yields.

[0004] There is a need for novel and improved methods for cleaning substrate surfaces that overcome one or more of the aforementioned drawbacks. Summary of the Invention

[0005] Embodiments of this disclosure generally relate to methods and systems for cleaning substrate surfaces.

[0006] In one embodiment, a method for processing a substrate is provided. The method includes introducing the substrate into a processing space of a processing chamber by positioning the substrate on a substrate support. The method further includes flowing a first processing gas, comprising HF, flowing a second processing gas, comprising pyridine, pyrrole, aniline, or a combination thereof, into the processing space, and exposing the substrate to the first and second processing gases to remove oxides from the substrate under oxide removal conditions.

[0007] In another embodiment, a method for processing a substrate is provided. This method includes introducing the substrate into a processing space of a processing chamber by positioning the substrate on a substrate support. The method further includes flowing a first processing gas, comprising HF, into the processing space, flowing a second processing gas, comprising pyridine, pyrrole, aniline, or a combination thereof, and exposing the substrate to the first and second processing gases to remove oxides from the substrate in an oxide removal state. The oxide removal state includes maintaining the substrate support at a temperature of about –10°C to about 80°C, maintaining the processing space at a pressure of about 600 Torr or less, or a combination of the foregoing states.

[0008] In another embodiment, a system is provided. This system includes a processing chamber for processing a substrate, and a controller for performing a processing method within the processing chamber. The processing method includes introducing the substrate into a processing space of the processing chamber by positioning the substrate on a substrate support, flowing a first processing gas comprising HF into the processing space, flowing a second processing gas into the processing space comprising pyridine, pyrrole, aniline, or a combination thereof, and exposing the substrate to the first and second processing gases to remove oxides from the substrate in an oxide-removed state.

[0009] In another embodiment, a system is provided. This system includes a processing chamber for processing a substrate, and a controller for performing a processing method within the processing chamber. The processing method includes introducing the substrate into a processing space of the processing chamber by positioning the substrate on a substrate support, introducing a first processing gas comprising HF into the processing space, introducing a second processing gas comprising pyridine, pyrrole, aniline, or a combination thereof into the processing space, and exposing the substrate to the first and second processing gases to remove oxides from the substrate in an oxide removal state. The oxide removal state includes maintaining the substrate at a temperature of about –10°C to about 80°C, maintaining the processing space at a pressure of about 600 Torr or less, or a combination of the foregoing states. Attached Figure Description

[0010] By referring to the embodiments, some of which are illustrated in the accompanying drawings, a more specific description of the present disclosure, which is briefly summarized above, can be obtained, and the manner in which the features of the present disclosure are used can be understood in detail. However, it will be noted that the accompanying drawings illustrate only exemplary embodiments of the present disclosure and are therefore not intended to limit the scope of the present disclosure, as the present disclosure can be applied to other equivalent embodiments.

[0011] Figure 1A This is a flowchart of an instance processing sequence 100 according to at least one embodiment of the present disclosure.

[0012] Figure 1B This is a flowchart of an example method for processing a substrate according to at least one embodiment of the present disclosure.

[0013] Figure 2A It is for performing according to at least one embodiment of the present disclosure. Figure 1A-Figure 1B A cross-sectional view of a chamber processed by one or more instances of operations.

[0014] Figure 2B It is based on at least one embodiment of this disclosure. Figure 2A An enlarged view of a portion of the processing chamber.

[0015] Figure 2C This is an enlarged cross-sectional view of an example substrate support member according to at least one embodiment of the present disclosure.

[0016] For ease of understanding, the same reference numerals have been used as much as possible to refer to the same elements common in the figures. It is contemplated that elements and features of one embodiment may be advantageously incorporated into other embodiments without further explanation. Detailed Implementation

[0017] Embodiments of this disclosure generally relate to methods and systems for cleaning substrate surfaces. Inventors have discovered novel and improved methods for removing oxides, such as native oxides, with, for example, high conformality and high selectivity compared to other dielectric materials. In short, and in some instances, the methods described herein utilize hydrogen fluoride (HF) and nitrogen-containing species (such as weakly basic amines, such as pyridine, pyrrole, aniline, or combinations thereof) to remove undesirable oxides on one or more surfaces of a high aspect ratio device feature.

[0018] Conventional cleaning processes are limited by salt formation, which pinches off the bottom of the trench, preventing reactants from reaching the oxide at the trench bottom. The formed salt then sublimates through an annealing operation. As an example, a typical cleaning process utilizes HF and NH3, which form a (NH4)2SiF6 hydrate at low temperatures (e.g., below 20°C). This hydrate then sublimates at temperatures above 100°C. This results in low manufacturing yields due to the multiple cycles of salt formation at <20°C and annealing at >100°C. Furthermore, conventional methods do not exhibit optimal selectivity. The surface to be cleaned is adjacent to dielectrics, such as spacers and hard masks, which should not be damaged or etched by the cleaning process. While conventional cleaning processes remove oxides, they can undesirably etch dielectrics such as SiN and / or SiON sidewall spacers or other features.

[0019] Compared to conventional processes, the method described herein is, for example, salt-free, highly selective, highly conformal, and effective for cleaning high aspect ratio features. Furthermore, the method described herein enables high-yield cleaning of high aspect ratio features, such as SiN or SiON sidewall spacers and hard masks, with minimal loss of dielectric material. In addition, the method described herein enables isotropic and conformal feature cleaning, thereby removing, for example, native oxides on the sidewall (110) silicon surface in addition to native oxides on the silicon surface (100). After cleaning, the finished substrate can be used for further processing, such as epitaxial growth and / or chemical vapor deposition of Si and / or Ge layers.

[0020] In the event of any complexes (e.g., (C5H5N)2SiF4) forming during the operation of the methods described herein, low-temperature annealing can be used to remove the complexes. Since the (C5H5N)2SiF4 complexes formed during the treatment sublimate at a lower temperature than salts such as (NH4)2SiF6 formed by conventional processes, this annealing can be performed at a lower temperature than conventional processes. Furthermore, although (C5H5NH)2SiF6 salts may form during the operation of the methods described herein, the formation of these salts is much slower than that of the (C5H5N)2SiF4 complexes. That is, complex formation is more dominant than salt formation. In the case of salt formation, such as (C5H5NH)2SiF6, this salt can be removed at a temperature greater than or equal to about 165°C.

[0021] In some instances, nitrogen-containing species such as pyridine (or anhydrous pyridine) are used together with HF (or anhydrous HF) for isotropic dry etching of SiO2 under vacuum. (C5H5NH) + and HF2 – The species, pyridine, catalyzes the HF conversion of SiO2 to SiF4 + H2O and / or the formation of (C5H5N)2SiF4 complexes with a sublimation temperature <80°C. Unlike known methods that use water, alcohols, or NH3 to achieve high HF etching selectivity relative to other dielectrics, the method described herein avoids wet HF corrosion, carbon contamination, and slow >100°C fluorosilicate annealing cycles. Even with multiple cycles of complex formation and annealing, the inventors observed faster yields compared to conventional methods. The method described herein minimizes HF corrosion and carbon contamination by alternatively forming (C5H5N)2SiF4 complexes, or via pathways that could otherwise use water or alcohol catalysts, avoiding or at least mitigating the formation of high-melting-temperature salts ((C5H5NH)2SiF6), all while simultaneously avoiding selectivity reduction and salt trapping problems during native oxide cleaning at the bottom of high aspect ratio structures.

[0022] Figure 1AThis is a flowchart of an example processing sequence 100 according to at least one embodiment of the present disclosure. In block 102, a cleaning process is used to remove oxides from the surface of a semiconductor substrate. The substrate may include a silicon-containing material and the surface may include materials such as silicon (Si), germanium (Ge), or a silicon-germanium alloy (SiGe). In some embodiments, the Si, Ge, or SiGe surface may have an oxide layer, such as a native oxide layer, and contaminants disposed thereon. Due to the sensitivity of epitaxial deposition processes to oxides and contaminants (such as carbonaceous contaminants), surface contamination caused by exposure to a typical cleanroom environment for several hours can become significant enough to accumulate oxides and contaminants, affecting the quality of the subsequently formed epitaxial layer.

[0023] The substrate surface can be cleaned by performing oxide removal and contaminant removal processes. In one embodiment, a cleaning process is used to remove oxides from the substrate surface (box 102), and a reduction process, for example, is used to remove contaminants such as carbon-containing contaminants from the substrate surface (box 103). Example processing chambers that may be employed to perform the cleaning processes described herein include Clarion. TM The chamber is available from Applied Materials, Inc., Santa Clara, California. Chambers from other manufacturers may also be used.

[0024] In optional box 103, a second cleaning process can be performed by removing carbon contaminants from the substrate surface. The cleaning process for removing carbon contaminants (box 103) can be performed before or after oxide removal (box 102). The operation of box 103 can be performed in the same processing chamber as those operations related to box 102 or in a different processing chamber. The operation of boxes 102 and 103 results in a uniform, oxide- and contaminant-free substrate surface, which improves the quality of layers subsequently formed on the substrate surface.

[0025] In frame 104, an epitaxial layer is formed on the substrate surface. Exemplary epitaxial processes can be selective epitaxial processes performed at temperatures below about 800°C, for example, from about 450°C to about 650°C. The epitaxial layer can be formed using a high-temperature chemical vapor deposition (CVD) process. The epitaxial layer can be crystalline silicon, germanium, or silicon-germanium, or any suitable semiconductor material such as group III-V or group II-VI compounds. In an exemplary thermal CVD process, materials such as chlorosilane SiH... x Cl 4-x (Single, Di, Tri, Tetra), Silane Si x H 2X+2 (Silane, disilane, trisilane, etc.), germanane (Ge) x H 2x+2Processing gases, such as germane, digermane, etc., hydrogen chloride (HCl), chlorine (Cl2), or combinations thereof, are used to form the epitaxial layer. The processing temperature is about 800°C or lower, such as from about 300°C to about 600°C, for example, about 450°C, and the processing pressure is from about 5 Torr to about 600 Torr. In at least one embodiment, the processing chamber for performing the operation of block 104 may be a film forming chamber, such as a vapor phase epitaxial deposition chamber, for example, an Epi chamber available from Applied Materials, Santa Clara, California, capable of forming crystalline silicon or silicon-germanium. In other embodiments, the processing chamber for performing the operation of block 104 may be an epitaxial deposition chamber, such as a single-substrate processing chamber. In other embodiments, the processing chamber may be a CVD or epitaxial deposition processing chamber. An example processing chamber that can be used to perform an epitaxial deposition process is the Centura. TM Epi chambers are available from Applied Materials in Santa Clara, California. Chambers from other manufacturers may also be used.

[0026] In a non-limiting example, the cleaning process (oxide removal process) of box 102 may include those shown in the diagram. Figure 1B The operations described in the flowchart of process 150 are as follows. Process 150 includes a processing area in operation 152 where a substrate is introduced (e.g., transferred, transported, etc.) into a substrate processing chamber. The substrate may be transferred into the processing chamber by any suitable means. The substrate may include a silicon-containing material and the surface may include a material such as silicon (Si), germanium (Ge), or a silicon-germanium alloy (SiGe). In some embodiments, the Si, Ge, or SiGe surface may have an oxide layer, such as a native oxide layer, and contaminants disposed thereon.

[0027] Process 150 further includes inflowing one or more process gases into a process space in operation 154. The process gases include and / or are formed from HF and one or more nitrogen-containing species, such as weakly basic amines. The nitrogen-containing species may be formed from one or more nitrogen-containing compounds. Non-limiting examples of nitrogen-containing compounds include pyridine, pyrrole, aniline, or combinations thereof. Anhydrous HF and / or anhydrous nitrogen-containing species may be used.

[0028] In some embodiments, a first processing gas containing HF flows into the processing space through an inlet, and a second processing gas containing nitrogen-containing species flows through the same or different inlets. Alternatively, a first processing gas containing a mixture of HF and nitrogen-containing species flows through a first inlet, and a second processing gas containing nitrogen-containing species flows through a second inlet. In these and other embodiments, the ratio of nitrogen-containing species to HF can be adjusted.

[0029] In some embodiments, the first processing gas and the second processing gas flow into the processing space together. For example, a first processing gas containing HF and a second processing gas containing one or more nitrogen-containing species flow into the processing space together. Alternatively, the second processing gas may flow into the processing space intermittently while the first processing gas flows into the processing space, or vice versa.

[0030] Alternatively, a first processing gas containing HF and a second processing gas containing one or more nitrogen-containing species may be successively introduced into the processing space. For example, the nitrogen-containing species enters the processing space, followed by HF, and then the nitrogen-containing species re-enters the processing space. As another example, HF enters the processing space, followed by the nitrogen-containing species, and then HF re-enters the processing space. As yet another example, HF and the nitrogen-containing species co-enter the processing space, then the flow of the nitrogen-containing species is stopped while HF continues to flow into the processing space. The flow of the nitrogen-containing species is resumed after a certain period of time. As described later, one or more ampoules, one or more bubblers, and / or one or more liquid evaporators may be used to provide HF, one or more nitrogen-containing species, or a combination of the foregoing to the processing chamber.

[0031] Process 150 further includes exposing the substrate to a process gas in operation 156 while in an oxide-removed state. The oxide removal process is highly conformal and highly selective for oxide layers, thus preventing easy etching of silicon, germanium, or nitride layers, regardless of whether these layers are amorphous, crystalline, or polycrystalline. In some embodiments, the oxide-to-silicon or-germanium selectivity of the oxide removal process is at least about 10:1, such as about 30:1, such as about 50:1, or better, such as about 100:1. In some embodiments, the oxide removal process may also be highly selective for oxides to nitrides. In a non-limiting example, the oxide-to-nitride selectivity of the oxide removal process is at least about 5:1, such as about 10:1, or better, such as about 20:1.

[0032] In some embodiments, during or after the oxide removal process, a amount of thermal energy may be applied to the substrate to aid in the removal of any generated byproducts, such as the complexes and / or salts described above. In some embodiments, the thermal energy is provided via radiation, convection, and / or conduction heat transfer processes, causing undesirable byproducts found on the substrate surface to sublimate.

[0033] Various operations of the example processes described herein (e.g., block 102 or process 150) may include one or more process parameters described later.

[0034] During oxide removal, the temperature of the substrate can be about 100 °C or less, such as from about -20 °C to about 90 °C, such as from about -10 °C to about 80 °C, such as from about 0 °C to about 60 °C. In at least one embodiment and during oxide removal, the temperature of the substrate support ranges from T1 to T2 (in °C), where T1 and T2 are each independently about -20, about -15, about -10, about -5, about 0, about 5, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, or about 100, provided that T1 < T2. Selectivity can be improved at lower temperatures (e.g., below about 20 °C), while higher etch rates can be observed at higher temperatures.

[0035] The continuous supply of pyridine and the higher flow ratio of pyridine to HF are beneficial for the formation of amine complexes during processing, e.g., (C5H5N)2SiF4. The temperature of the substrate can be raised to about 50 °C or higher, such as about 60 °C to about 80 °C, to partially or completely sublime the complex during and / or after exposing the substrate to the processing gas. The substrate temperature can be cycled between the sublimation temperature and a cooler, more selective etch temperature. The substrate temperature can be adjusted, for example, between the cooler substrate support temperature and the hotter temperature of the process chamber lid by positioning the substrate closer to the lid for sublimation and farther from the lid for selective etching. If salts are formed during processing, e.g., (C5H5NH)2SiF6, the substrate temperature can be raised to from about 120 °C to about 180 °C, such as from about 150 °C to about 170 °C, such as from about 155 °C to about 165 °C. As previously mentioned, complex formation generally has advantages over salt formation, thus avoiding or mitigating salt pinning and reducing the temperature for substrate cleaning relative to conventional processes.

[0036] The pressure within the processing space can be about 600 Torr or less, such as about 300 Torr or less, such as about 100 Torr or less, such as about 10 Torr or less. In at least one embodiment, the pressure within the processing space ranges from P1 to P2 (in Torr), where P1 and P2 are each independently about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 20, about 30, about 40, about 50, about 60, about 70, about 80, about 90, about 100, about 150, about 200, about 250, about 300, about 350, about 400, about 450, about 500, about 550, or about 600, provided that P1 < P2.

[0037] The HF flow rate into the processing space for a 300mm-sized substrate can be about 50 standard cubic centimeters per minute (sccm) or less, such as from about 1 sccm to about 50 sccm, such as from about 2 sccm to about 20 sccm. In at least one embodiment, the HF flow rate into the processing space for a 300mm-sized substrate ranges from flow rate 1 to flow rate 2 (in sccm), wherein flow rate 1 and flow rate 2 are each independently about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19. Approximately 20, approximately 21, approximately 22, approximately 23, approximately 24, approximately 25, approximately 26, approximately 27, approximately 28, approximately 29, approximately 30, approximately 31, approximately 32, approximately 33, approximately 34, approximately 35, approximately 36, approximately 37, approximately 38, approximately 39, approximately 40, approximately 41, approximately 42, approximately 43, approximately 44, approximately 45, approximately 46, approximately 47, approximately 48, approximately 49, or approximately 50, provided that flow rate 1 < flow rate 2.

[0038] The flow rate of one or more nitrogen-containing species into the processing space can be about 100 sccm or less for a 300 mm size substrate, such as from about 0.1 sccm to about 250 sccm, such as from about 0.2 sccm to about 100 sccm, such as from about 1 sccm to about 50 sccm. In at least one embodiment, the flow rate of one or more nitrogen-containing species entering the processing chamber ranges from flow rate 3 to flow rate 4 (in sccm) for a 300mm size substrate, wherein flow rate 3 and flow rate 4 are each independently about 0.1, about 0.2, about 0.5, about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 31, about 32, about 33, about 34, about 35, about 36, about 37, about 38, about 39, about 40, about 41, about 4 ... 42, about 43, about 44, about 45, about 46, about 47, about 48, about 49, or about 50, about 51, about 52, about 53, about 54, about 55, about 56, about 57, about 58, about 59, about 60, about 61, about 62, about 63, about 64, about 65, about 66, about 67, about 68, about 69, about 70, about 71, about 72, Approximately 73, approximately 74, approximately 75, approximately 76, approximately 77, approximately 78, approximately 79, approximately 80, approximately 81, approximately 82, approximately 83, approximately 84, approximately 85, approximately 86, approximately 87, approximately 88, approximately 89, approximately 90, approximately 91, approximately 92, approximately 93, approximately 94, approximately 95, approximately 96, approximately 97, approximately 98, approximately 99, or approximately 100, provided that flow rate 3 < flow rate 4.

[0039] The flow rate ratio of nitrogen-containing species to HF for a 300 mm substrate can be from about 0.1 to about 5, such as from about 0.2 to about 2, such as from about 0.5 to about 1.5. In at least one embodiment, the flow rate ratio of nitrogen-containing species to HF for a 300 mm substrate ranges from Example 1 to Example 2, wherein Example 1 and Example 2 are each independently about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1.0, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, or about 2.0. Approximately 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0, provided that ratio 1 < ratio 2.

[0040] In some embodiments, a mixture of HF and a nitrogen-containing species (e.g., HF-pyridine) may be delivered to the processing space via an inlet, and the nitrogen-containing species may be delivered to the processing space via the same or different inlets. In at least one embodiment, the range of HF / nitrogen-containing species mixtures delivered through a single inlet is from mixture 1 to mixture 2, wherein mixture 1 and mixture 2 are each independently of about 10%:90%, about 20%:80%, about 30%:70%, about 40%:60%, about 50%:50%, about 60%:40%, about 70%:30%, about 80%:20%, or about 90%:10%, provided that mixture 1 < mixture 2.

[0041] In some embodiments, non-reactive processing gases, such as inert gases like helium (He), neon (Ne), argon (Ar), krypton (Kr), and / or xenon (Xe), can be used with HF, nitrogen-containing gases, or both HF and nitrogen-containing gases. Non-reactive processing gases can be used as carrier gases and / or purging gases during substrate processing. For example, non-reactive processing gases can help maintain low moisture pressure during processing, which helps mitigate salt formation.

[0042] Optional heat treatment may be performed between or after the processes relating to blocks 102 and 103, and before the layer forming process of 104, to remove any residual byproducts or contaminants, and to anneal the surface to remove any surface defects. This heat treatment may be performed in, for example, a hydrogen atmosphere (optionally including non-reactive gases such as argon and / or helium), and at temperatures ranging from about 400°C to about 800°C and pressures ranging from about 1 Torr to about 300 Torr.

[0043] Figure 2A This is a cross-sectional view of an example processing chamber 200 adapted to perform at least some operations related to frame 102 and process 150 according to at least one embodiment of the present invention. The processing chamber 200 is thus configured to remove contaminants such as oxides from the substrate surface. Figure 2B yes Figure 2A An enlarged view of a portion of the processing chamber 200.

[0044] Processing chamber 200 is particularly useful for performing dry thermal etching processes in a vacuum. Processing chamber 200 includes a chamber body 212, a cover assembly 214, and a support assembly 216. The cover assembly 214 is disposed at the upper end of the chamber body 212, and the support assembly 216 is at least partially disposed within the chamber body 212. A vacuum system is used to remove gases from the processing chamber 200. The vacuum system includes a vacuum pump 218 coupled to a vacuum port 221 disposed within the chamber body 212. Processing chamber 200 also includes a controller 202 for controlling the process within the processing chamber 200.

[0045] The cover assembly 214 includes a plurality of stacked components configured to provide precursor gas to a processing space 222 within the processing chamber 200. A gas source 252 is coupled to the cover assembly 214 via a first plate 220. The gas source 252 may be configured to provide a non-reactive gas, such as an inert gas. Exemplary, non-limiting examples of non-reactive gases include He, Ne, Ar, Kr and / or Xe, or other non-reactive gases.

[0046] Reference Figure 2B An opening 246 allows gas to flow from a gas source 252 to a space 248 formed in a second plate 250 of the cover assembly 214. A central conduit 270 formed in the second plate 250 is adapted to provide gas from space 248 through a third plate 254 to a mixing chamber 266 formed in a fourth plate 268 of the cover assembly 214. The central conduit 270 communicates with the mixing chamber 266 through an opening 264 in the third plate 254. The opening 264 may have a diameter smaller than, larger than, or the same as that of the central conduit 270. Figure 2B In one embodiment, the opening 264 has the same or substantially the same diameter as the central conduit 270.

[0047] The second plate 250 also includes a plurality of inlets 256 and 258 configured to provide gas to the mixing chamber 266. Inlet 256 is coupled to a first gas source 260 and inlet 258 is coupled to a second gas source 262. The first gas source 260 and the second gas source 262 may contain a process gas and a non-reactive gas, such as an inert gas like argon and / or helium, used as a carrier gas. The first gas source 260 may contain a nitrogen-containing species (e.g., pyridine). The second gas source 262 may contain a fluorine-containing gas and a hydrogen-containing gas. In one example, the second gas source 262 may contain hydrogen fluoride (HF). The first gas source 260 and / or the second gas source 262 may contain one or more non-reactive gases.

[0048] The first gas source 260 and / or the second gas source 262 may include one or more ampoules, one or more bubblers, and / or one or more liquid evaporators configured to provide a processing gas. For example, in the case of using a liquid precursor (e.g., a mixture of pyridine and / or HF / pyridine), the first gas source 260 and / or the second gas source 262 may include a liquid evaporator in fluid communication with a liquid precursor source (not shown). The liquid evaporator can be used to evaporate the liquid precursor to be delivered to the cap assembly 214. Although not shown, it is contemplated that the liquid precursor source may include one or more ampoules of, for example, a precursor liquid and a solvent liquid, a shut-off valve, and a liquid flow meter (LFM). As an alternative to the liquid evaporator, a bubbler may be used to deliver the liquid precursor to the chamber. In this case, the ampoule of the liquid precursor is connected to the processing space of the chamber via a bubbler.

[0049] like Figure 2B As shown, in some embodiments, inlet 256 is coupled to mixing chamber 266 via cylindrical channel 259 (shown as dashed lines) and a plurality of holes 265 formed in third plate 254. Inlet 258 is coupled to mixing chamber 266 via cylindrical channel 257 (shown as dashed lines) and a plurality of holes 267 formed in third plate 254. The holes 265, 267 formed in third plate 254 are generally sized to allow uniform flow of gas (provided by their individual gas sources 260, 262) into mixing chamber 266. In one configuration, holes 267 have a diameter smaller than the width of the opening defined by the opposing sidewalls of cylindrical channel 257 formed in second plate 250. Holes 267 are generally distributed around the central line of cylindrical channel 257 to provide uniform fluid flow into mixing chamber 266. In one configuration, the perforations 265 have a diameter smaller than the width of the opening defined by the opposing sidewalls of the cylindrical channel 259 formed in the second plate 250. The perforations 265 are generally distributed around the central line of the cylindrical channel 259 to provide uniform fluid flow into the mixing chamber 266.

[0050] Inlets 256 and 258 provide individual fluid flow paths that pass laterally through the second plate 250, detour, and through the third plate 254 to the mixing chamber 266. The cover assembly 214 also includes a fifth plate or a first gas distributor 272, which may be a gas distribution plate, such as a nozzle, through which the various gases mixed in the cover assembly 214 flow through perforations 274 formed in the fifth plate or the first gas distributor 272. The perforations 274 are in fluid communication with the mixing chamber 266 to provide a flow path from the mixing chamber 266 through the first gas distributor 272. (Refer to previous section) Figure 2A The barrier plate 228 and the gas distribution plate (such as a second gas distributor 230, which may be a gas distribution plate, such as a nozzle) are disposed below the cover assembly 214.

[0051] Support assembly 216 may include substrate support 232 to support substrate 210 thereon during processing. Substrate support 232 is coupled to actuator 234 by shaft 236 extending through a central positioning opening formed in the bottom of chamber body 212. Actuator 234 is flexibly sealed to chamber body 212 by a bellows (not shown) to prevent vacuum leakage around shaft 236. Actuator 234 allows substrate support 232 to move vertically within chamber body 212 between a processing position and a loading position. The loading position is slightly below the opening of a tunnel (not shown) formed in the sidewall of chamber body 212.

[0052] The substrate support 232 has a flat or substantially flat substrate support surface for supporting the substrate to be processed thereon. The substrate support 232 is vertically movable within the chamber body 212 by an actuator 234 coupled to the substrate support 232 by a shaft 236. For some operations, the substrate support 232 can be raised to a position adjacent to the cover assembly 214 to control the temperature of the substrate 210 being processed. Thus, the substrate 210 can be heated via radiation emitted from the second gas distributor 230 or another radiation source, or by convection or conduction of an intervening gas passing through the second gas distributor 230. In some process steps, the substrate can be positioned on the lifting pin 251 to perform additional heat treatment steps, such as annealing.

[0053] Figure 2C yes Figure 2AAn enlarged cross-sectional view of the substrate support 232. The substrate support 232 includes a heat control chamber 235 in fluid communication with a fluid supply conduit 241 and a fluid return conduit 243. The fluid supply conduit 241 and the fluid return conduit 243 are respectively disposed through a shaft 236. By circulating cooling fluid through the fluid supply conduit 241, entering the heat control chamber 235, and exiting through the fluid return conduit 243, the heat control chamber 235 provides a cooling feature for the substrate support 232.

[0054] The substrate support 232 may also include multiple heaters. In this embodiment, the multiple heaters include a first heater 237 and a second heater 239. The first heater 237 and the second heater 239 are disposed at a location within the substrate support 232 in a substantially coplanar relationship, so that the heaters can be thermally coupled to the substrate support surface. The first heater 237 is disposed around the substrate support 232, while the second heater 239 is disposed in the central region of the substrate support 232 to provide regional temperature control. Each of the first heater 237 and the second heater 239 may be a resistance heater, which is coupled to one or more power sources (not shown) by individual electrical conduits 249 and 247, each of which is disposed through the shaft 236.

[0055] In operation, temperature control is provided by the simultaneous operation of the thermal control chamber 235, the first heater 237, and the second heater 239. The thermal control chamber 235, as described above, can supply cooling fluid, and power can be provided to the first heater 237 and the second heater 239 as resistance heaters. In this way, individual control circuits can be adjusted to provide a rapid response to a single item, such as the first heater 237 and the second heater 239, and a slower response to the thermal control chamber 235, or vice versa. At least, different control parameters can be applied to the thermal control chamber 235, the first heater 237, and the second heater 239 to achieve an optimized zone temperature control system.

[0056] like Figure 2C As shown, a separate lifting member 245 may be included in the support assembly 216. A recess may be provided in the substrate support surface to receive the lifting pin 251 of member 245 when the substrate is placed on the substrate support surface. Lifting member 245 may be coupled to lifting actuator 255 via an extension of lifting member 245 provided through shaft 236. Lifting actuator can move lifting member 245 vertically to lift the substrate away from the substrate support surface toward the first gas distributor 272. Lifting member 245 may be a hoop, such as an open hoop or a closed hoop, which may be U-shaped, circular, horseshoe-shaped, or any convenient shape. Lifting member 245 has a thickness to provide structural strength when lifting the substrate. In one example, the lifting member is made of ceramic material and is approximately 1 mm thick.

[0057] The following illustrative but non-limiting examples are not intended to limit the scope of implementation of this disclosure.

[0058] Example

[0059] exist Figure 2A The processing chamber 200 can be executed Figure 1B Example process 150 and Figure 1A The oxide removal process is illustrated in box 102. The substrate is positioned in the processing space 222 by positioning it on a substrate support 232. Pyridine is routed from a first gas source 260 through inlet 256, and HF is routed from a second gas source 262 through inlet 258. HF flows through inlet 258 at a rate of 2–20 sccm, and pyridine flows through inlet 256 at a rate of approximately 0.2 to 2 times that of HF. During etching, the substrate is maintained at a temperature from approximately –10°C to approximately 15°C, with or without (C5H5N)2SiF4 complex formation. The substrate is maintained at this temperature by, for example, by passing a temperature-controlled fluid through a thermal control gas chamber 235. The substrate support 232 may be powered to provide radial temperature control. The chamber is maintained at a pressure of approximately 600 Torr or less, and the substrate is processed for a duration suitable for converting all desired oxides on the substrate surface into volatile SiF4 or its amine complexes, for example, 100 seconds. If annealing is desired, the annealing temperature can be approximately 80°C or lower.

[0060] In some implementations, existing chambers used for etching / cleaning can be improved. For example, NH3, water, and / or alcohol circuitry in chambers using HF can be replaced by pyridine circuitry, such as Clarion. TM Chamber. Anhydrous pyridine can be delivered using a bubbler, and anhydrous HF can be delivered via the equipment gas line, or as an HF-pyridine mixture in the bubbler (e.g., HF ~ 70%, pyridine ~ 30%).

[0061] The method described herein can remove unwanted oxides from one or more surfaces of high aspect ratio devices. This method is salt-free, highly selective, and provides high-volume cleaning of high aspect ratio features with minimal loss of dielectric material. Furthermore, the method achieves isotropic and conformal cleaning characteristics. Compared to current state-of-the-art methods, the method described herein minimizes HF corrosion and carbon contamination, while simultaneously avoiding reduced selectivity and salt trapping problems during the cleaning of native oxides at the bottom of high aspect ratio structures.

[0062] In the foregoing, reference has been made to embodiments of this disclosure. However, it should be understood that this disclosure is not limited to the specifically described embodiments. Rather, any combination of the following features and elements, whether or not relating to different embodiments, is contemplated for implementing and carrying out this disclosure. Furthermore, while embodiments of this disclosure may achieve advantages over other possible solutions and / or prior art, they do not limit this disclosure regardless of whether a given embodiment achieves a particular advantage. Therefore, the foregoing aspects, features, embodiments, and advantages are merely illustrative and should not be construed as elements or limitations of the appended claims unless expressly stated in the claims. Similarly, reference to “this disclosure” should not be construed as a generalization of any progressive objectives disclosed herein and should not be construed as elements or limitations of the appended claims unless expressly stated in the claims.

[0063] For the purposes of this disclosure, and unless otherwise specified, all numerical values ​​within the embodiments and claims herein are modified by “about” or “approximately” to indicate such values, and take into account experimental errors and variations anticipated by those skilled in the art. For brevity, only specific ranges are explicitly disclosed herein. However, a range from any lower limit value may be combined with any upper limit value to describe a range not explicitly stated, and a range from any lower limit value may be combined with any other lower limit value to describe a range not explicitly stated, and in the same manner, a range from any upper limit value may be combined with any other upper limit value to describe a range not explicitly stated. Furthermore, even if not explicitly stated, a range includes every point or individual value between its endpoints. Thus, each point or individual value may be combined with any other point or individual value or any other lower or upper limit value as its own lower or upper limit value to describe a range not explicitly stated.

[0064] When used here, the indefinite article “a” or “an” should mean “at least one” unless explicitly stated otherwise or the context clearly indicates otherwise.

[0065] While the foregoing describes embodiments of this disclosure, other and further embodiments of this disclosure may be conceived without departing from the basic scope of this disclosure, and the scope of this disclosure is defined by the appended claims.

Claims

1. A method for processing a substrate, comprising: The substrate is introduced into the processing space of the processing chamber by positioning the substrate on the substrate support. A first processing gas, comprising HF, is flowed into the processing space. A second processing gas is introduced into the processing space, the second processing gas comprising pyridine, pyrrole, aniline, or a combination of the foregoing; and The substrate is exposed to the first processing gas and the second processing gas under oxide removal conditions to remove oxides from the substrate, the oxide removal conditions including: The substrate is maintained at a temperature ranging from -10°C to 80°C; and / or Maintain the processing space at a pressure of 600 Torr or less.

2. The method of claim 1, wherein the first processing gas and the second processing gas flow together into the processing space.

3. The method of claim 1, wherein when the first processing gas flows into the processing space, the second processing gas flows into the processing space intermittently.

4. The method of claim 1, further comprising forming a film on the substrate by vapor phase epitaxy.

5. The method of claim 1, further comprising cooling the substrate while removing the oxide from the substrate.

6. The method of claim 1, further comprising heating the substrate to a temperature of 50°C to 80°C after exposure to the first processing gas and the second processing gas or between exposure to the first processing gas and the second processing gas.

7. The method of claim 1, further comprising, after removing at least a portion of the oxide from the substrate, performing a heat treatment process on the substrate, the heat treatment process comprising: Inert gas is introduced into the processing chamber; and The substrate is maintained at a temperature of 400°C or higher.

8. The method of claim 1, wherein exposing the substrate to the first processing gas and the second processing gas comprises: Maintain the substrate at a temperature from 0°C to 60°C; and / or Maintain the processing space at a pressure of 10 Torr or less.

9. The method of claim 1, wherein: The flow rate of the first processing gas entering the processing space is 1 sccm to 50 sccm for a 300 mm substrate; and / or The flow rate ratio of the second processing gas to the first processing gas is 0.1 to 5.

10. The method of claim 1, wherein: The flow rate of the first processing gas entering the processing space is 2 sccm to 20 sccm for a 300 mm substrate; and / or The flow rate ratio of the second processing gas to the first processing gas is 0.2 to 2.

11. A system comprising: Processing chamber, the processing chamber processing substrate; and A controller, the controller causing a processing method to be executed in the processing chamber, the processing method comprising: The substrate is introduced into the processing space of the processing chamber by positioning the substrate on the substrate support. A first processing gas, comprising HF, is flowed into the processing space. A second processing gas is introduced into the processing space, the second processing gas comprising pyridine, pyrrole, aniline, or a combination of the foregoing; and The substrate is exposed to the first processing gas and the second processing gas under oxide removal conditions to remove oxides from the substrate, the oxide removal conditions including: The substrate is maintained at a temperature ranging from -10°C to 80°C; and / or Maintain the processing space at a pressure of 600 Torr or less.

12. The system of claim 11, wherein exposing the substrate to the first processing gas and the second processing gas comprises: The substrate is maintained at a temperature ranging from 0°C to 60°C.

13. The system of claim 11, wherein: The flow rate of the first processing gas entering the processing space is 1 sccm to 50 sccm for a 300 mm substrate; and / or The flow rate ratio of the second processing gas to the first processing gas is 0.1 to 5.

14. The system of claim 11, wherein: The flow rate of the first processing gas entering the processing space is 2 sccm to 20 sccm for a 300 mm substrate; and / or The flow rate ratio of the second processing gas to the first processing gas is 0.2 to 2.

15. The system of claim 11, further comprising heating the substrate to a temperature of 50°C to 80°C after exposure to the first processing gas and the second processing gas or between exposure to the first processing gas and the second processing gas.

16. A system comprising: Processing chamber, the processing chamber processing substrate; and A controller, the controller causing a processing method to be executed in the processing chamber, the processing method comprising: The substrate is introduced into the processing space of the processing chamber by positioning the substrate on the substrate support. A first processing gas, comprising HF, is flowed into the processing space. A second processing gas is introduced into the processing space, the second processing gas comprising pyridine, pyrrole, aniline, or a combination of the foregoing; and The substrate is exposed to the first processing gas and the second processing gas to remove oxides from the substrate in an oxide removal state, the oxide removal state comprising: Maintain the substrate at a temperature from -10°C to 80°C; and / or Maintain the processing space at a pressure of 600 Torr or less; The flow rate of the first processing gas entering the processing space is 2 sccm to 20 sccm for a 300 mm substrate; and / or The flow rate ratio of the second processing gas to the first processing gas is 0.1 to 5.

17. The system of claim 16, wherein the oxide removal state comprises: Maintain the substrate at a temperature from 0°C to 60°C; and / or Maintain the processing space at a pressure of 10 Torr or less.

18. The system of claim 17, wherein the flow rate ratio of the second processing gas to the first processing gas is 0.2 to 2.

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