WO2019125933A1

WO2019125933A1 - Method and precursor selection for flowable silicon dioxide gap fill for advanced memory application

Info

Publication number: WO2019125933A1
Application number: PCT/US2018/065628
Authority: WO
Inventors: Prerna S. Goradia; Atul CHAUDHARI; Tapash Chakraborty; Nilesh BAGUL; Ranga Rao Arnepalli; Pramit MANNA; Abhijit Basu Mallick; Robert Jan Visser; Darshan THAKARE; Jonathan Frankel; Nilesh Patil; Govindraj DESAI; Srobona SEN
Original assignee: Applied Materials, Inc.
Priority date: 2017-12-19
Filing date: 2018-12-14
Publication date: 2019-06-27

Abstract

Embodiments described herein relate to apparatus and methods for performing aerosol assisted chemical vapor deposition (AACVD) processes. In an embodiment, a solution of a silica nanoparticle and a solvent is atomized to form an aerosol which is delivered to a process chamber. A silicon oxide material is formed on a substrate in the process chamber. In another embodiment, a silicon containing liquid precursor is atomized to form an aerosol which is delivered to a process chamber along with an oxidant. A silicon oxide material is formed on a substrate in the process chamber. Other embodiments described herein provide for AACVD processes which form silicon oxide materials on a substrate.

Description

METHOD AND PRECURSOR SELECTION FOR FLOWABLE SILICON DIOXIDE GAP FILL FOR ADVANCED MEMORY APPLICATION

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to material deposition methods. More specifically, embodiments described herein relate to large area gap fill methods for advanced memory devices.

Description of the Related Art

[0002] It is contemplated that the market for advanced memory devices, such as 3D NAND and 3D V-NAND devices, will grow rapidly to meet consumer demand for improved electronic device performance and capacity. Applications for such memory devices include solid state drives, hard drives, and high density memory storage devices, among others. 3D NAND does not utilize state of the art lithographical processes, thus resulting in reduced manufacturing costs when compared to planar NAND devices.

[0003] As the complexity of advanced memory devices increases, new deposition and etching techniques are desirable to efficiently fabricate defect free devices. For example, gap fill processes are utilized for depositing electrically insulating materials. However, at gap depths utilized with advanced memory devices, defects often exist in the insulating materials, large amounts of overburden exist outside of the gaps, and the deposition processes are inefficient.

[0004] Thus, what is needed in the art are improved gap fill methods and apparatus for gap fill methods.

SUMMARY

[0005] In one embodiment, a substrate processing method is provided. The method includes delivering an aerosol to a process region, the aerosol formed from a solution of a silica nanoparticle and a solvent; maintaining a temperature of the process region at a temperature less than a boiling point of the solvent; maintaining a temperature of a substrate at a temperature greater than a boiling point of the solvent; and depositing a polymeric silicon oxide (SiO_x) material on the substrate.

[0006] In another embodiment, a substrate processing method is provided. The method includes delivering an aerosol to a process region, the aerosol formed from a solution of tetraethylorthosiiicate, ethanol, water, and catalyst; maintaining a temperature of the process region at a temperature less than a boiling point of the ethanol; maintaining a temperature of a substrate at a temperature greater than a boiling point of ethanol; and depositing a polymeric silicon oxide material on the substrate.

[0007] In another embodiment, a substrate processing method is provided. The method includes delivering an aerosol to a process region, the aerosol formed from a solution of 1-methylsilanetriol and a solvent selected from water, methanol, ethanol, isopropanol; maintaining a temperature of the process region at a temperature about equal to a boiling point of the solution; maintaining a temperature of a substrate at a temperature less than the temperature of the process region and the boiling point of the solution; maintaining the process region at a pressure between about 50 Torr and about 200 Torr; depositing a polymeric silicon oxide material on the substrate; and annealing the polymeric silicon oxide material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the

disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

[0009] Figure 1 illustrates a schematic view of an aerosol assisted chemical vapor deposition (AACVD) apparatus according to an embodiment described herein.

[0010] Figure 2 illustrates a schematic, cross-sectional view of memory device according to an embodiment described herein.

[0011] Figure 3 illustrates operations of a method for performing an AACVD process according to an embodiment described herein.

[0012] Figure 4 illustrates operations of a method for performing an AACVD process according to an embodiment described herein.

[0013] Figure 5 illustrates operations of a method for performing an AACVD process according to an embodiment described herein.

[0014] Figure 6 illustrates operations of a method for performing an AACVD process according to an embodiment described herein.

[0015] Figure 7 illustrates operations of a method for performing an AACVD process according to an embodiment described herein.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0017] Embodiments described herein relate to apparatus and methods for performing aerosol assisted chemical vapor deposition (AACVD) processes. In some embodiments, a solution of a precursor and a solvent is atomized to form an aerosol which is delivered to a process chamber. A silicon oxide material is formed on a substrate in the process chamber. In another embodiment, a silicon containing liquid precursor is atomized to form an aerosol which is delivered to a process chamber along with an oxidant. A silicon oxide material is formed on a substrate in the process chamber. Other embodiments described herein provide for AACVD processes which form silicon oxide materials on a substrate.

[0018] Figure 1 illustrates a schematic view of an AACVD apparatus 100 according to an embodiment described herein. The apparatus 100, or other suitably configured AACVD type apparatus, is a useful environment to perform the methods described herein. Accordingly, the apparatus 100 is described concurrently with various method operations described in greater detail hereinafter.

[0019] The apparatus 100 includes a chamber body 106 which defines a process region 101. In some embodiments, the chamber body 106 is fabricated from a material capable of withstanding elevated process temperatures and maintaining vacuum integrity of a substrate processing environment during substrate processing therein. In some embodiments, the chamber body 106 is fabricated form a metallic material, such as stainless steel or aluminum. A lid 105, which is fabricated from a material similar to the material utilized for the chamber body 106, is coupled to the chamber body 106. In some embodiments, the chamber body 106 and/or lid 105 have heat transfer fluid channels formed therein and a heat transfer fluid is flowed through the channels to facilitate temperature control of the chamber body 106 and/or lid 105. In some embodiments, thermocouples are attached to or embedded within the chamber

body 106 and/or the lid 105 to provide feedback control of temperature and/or heat transfer fluid flow rate.

[0020] A pedestal 1 14 is disposed within the process region 101. In one embodiment, the pedestal 114 is vertically adjustable to position a substrate thereon at a process position within the process region 101. A substrate 113 is illustrated as being disposed on the pedestal 114. The substrate 113 is supported in the process region 101 by the pedestal 114 and is resistively heated and/or cooled by flowing a thermally controlled heat transfer fluid through channels in the pedestal 114. In some embodiments, the pedestal may be a rotatable pedestal. Rotation of the substrate can help the precursor flow into gaps in the substrate. Thus, in some embodiments, the substrate is disposed on the pedestal and the pedestal is rotated during deposition.

[0021] The process region 101 is bounded by a quartz baffle 112 and a quartz liner 116. The quartz baffle 112 and quartz liner 116 are generally selected based on their inertness to process chemistries utilized in the process region 101. The quartz baffle 112 and quartz liner 116 also facilitate a reduction in operational temperature of the chamber body 106 and the lid 105.

[0022] The process region 101 is coupled to and evacuated by a vacuum pump 117. In some embodiments, the process region 101 is evacuated, using the vacuum pump 117, prior to introducing aerosol droplets into the process region 101. Some chemicals utilized during processing operations may be subject to certain environmental controls prior to being released into the atmosphere. In some embodiments, a scrubber 118 is positioned downstream of, and in fluid communication with, the vacuum pump 117. The scrubber 118 modifies or removes certain chemical constituents of process effluent prior to atmospheric release of the effluent. In some embodiments, the vacuum pump 117 is utilized to form a closed-loop exhaust feedback system to maintain a desired subatmospheric pressure within the process region 101.

[0023] In one embodiment, the apparatus 100 includes a first aerosol generation system. To form the aerosol, a solid precursor is dissolved in a solvent, to form a precursor solution, and disposed in an aerosol generator 103-1 having a piezoelectric transducer 104-1 or other type of aerosol generating device. Alternately, a liquid precursor is used, and/or the precursors are used without a solvent, and is disposed in an aerosol generator 103-1 having a piezoelectric transducer 104-1. The precursor and precursor solutions can be varied according to deposition conditions. For example, concentration, type of silicon containing precursor, and type of solvent can be varied. Although the description below uses a precursor solution, it should be understood that a liquid precursor and/or precursors without a solvent can be used.

[0024] A carrier gas, which can be heated in a gas supply 102, and delivered into the aerosol generator 103-1. The piezoelectric transducer 104-1 is vibrated by applying an oscillating voltage to top and bottom surfaces of the transducer 104-1 which results in generation of aerosol droplets from a precursor solution (solid precursor + solvent) in the aerosol generator 103-1. The aerosol droplets are delivered through a precursor conduit 115-1 and enter the process region 101 through the lid 105. In certain embodiments, a carrier gas is flowed with the aerosol to facilitate transport of the aerosol through the precursor conduit 115-1. The aerosol droplets flow through a top electrode 109 and then through a bottom electrode 110 before entering the process region 101.

[0025] In another embodiment, the apparatus 100 includes a second aerosol generation system in addition to the first aerosol generation system. To generate an aerosol in a second aerosol generation system, a solid precursor is dissolved in a solvent and disposed in an aerosol generator 103-2 having a piezoelectric transducer 104-2. A carrier gas, which can be heated in a gas supply 102, and delivered into the aerosol generator 103-2. The piezoelectric transducer 104-2 is vibrated by applying an oscillating voltage to top and bottom surfaces of the transducer 104-2 which results in aerosol droplets which are generated from a

precursor solution (solid precursor + solvent) in the aerosol generator 103-2. The aerosol droplets are delivered through a precursor conduit 115-2 and enter the process region 101 through the lid 105. In certain embodiments, a carrier gas is flowed with the aerosol to facilitate transport of the aerosol through the precursor conduit 115-2. The aerosol droplets flow through the top electrode 109 and then through the bottom electrode 1 10 before entering the process region 101. In some embodiments, more than two aerosol generators 103, more than two transducers 104, and more than two precursor conduits 115 may be used.

[0026] In some embodiments,'" a DC electric field may optionally be applied between the top electrode 109 and bottom electrode 1 10 while aerosol droplets pass between the top electrode 109 and bottom electrode 110. The electric field is applied in an electric field region 111 oriented from the top electrode 109 to the bottom electrode 110. The chamber body 106 and lid 105 are also electrically insulated from one or both of the top electrode 109. The DC voltage difference is generated within a DC power supply 107 and passes into the process region 101 via vacuum compatible electrical feedthroughs.

[0027] The relatively small size of the aerosol droplets is reduced or maintained, in various embodiments, through application of the DC electric field which is perpendicular to a major plane of the substrate 113. The top electrode 109 and the bottom electrode 111 have perforations which allow the aerosol droplets to pass through both but are otherwise planar and each are parallel to the major plane of the substrate 113. It is also contemplated that the substrate 113 can be electrically biased during deposition processes.

[0028] The aerosol generators 103-1 , 103-2 are positioned close to the chamber body 106 and process region 101 to facilitate maintenance of small aerosol droplet sizes by reducing the distance the aerosol travels to the process region 101. A region within the aerosol generators 103-1 , 103-2 is roughly proportional to an area of the substrate 113 being processed. For example, a one liter aerosol generator is used to create aerosol droplets for a 300 mm

substrate. A mass flow controller 1 19 is disposed on the precursor conduits 1 15- 1 , 115-2 to control the flow rate of the carrier gas delivered to the process region 101. The carrier gas facilitates transfer of the aerosol droplets delivered to the process region 101.

[0029] Solid or liquid precursors are atomized or nebulized to form an aerosol which is utilized to deposit a film on the substrate 113. In embodiments utilizing solid precursors, the solid precursors are typically liquefied with a solvent in a solution prior to and/or during formation of the aerosol. In operation, a liquid precursor, which may be a solvated solid in solution, is placed in one or both of the aerosol generators 103-2, 103-2. A carrier gas is delivered into the aerosol generators 103-1 , 103-2. The transducers 104-1 , 104-2 are vibrated by applying a oscillating voltage and aerosol droplets are generated from the liquid precursor.

[0030] The aerosol droplets are then flowed through the respective precursor conduits 115-1 , 115-2 to the apparatus 100 through the lid 105. The aerosol droplets then flow through perforations in the top electrode 109 and through perforations in the bottom electrode 110 before entering the process region 101. Prior to entering the process region 101 , a DC voltage is applied between the top electrode 109 and the bottom electrode 110 while aerosol droplets pass between the two electrodes. The aerosol droplets may be charged, including field or diffusion charged, where the charge is transferred from the ionic current to the charged particles. The electric field is applied in the electric field region 1 11 and is oriented from the top electrode 109 towards the bottom electrode 110. The top electrode may be positively charged or negatively charged, depending on the charge of the aerosol.

[0031] An insulator 108 is coupled to the lid 105 and the insulator 108 is configured to maintain electrical separation between the top electrode 109 and the bottom electrode 110. The DC voltage difference is generated within the DC power supply 107 and current passes into the process region 101 through vacuum compatible electrical feedthroughs. The small size of the aerosol droplets is reduced or maintained, in certain embodiments, through application of the DC electric field which is perpendicular to the major plane of the substrate 113.

[0032] In certain embodiments, the pedestal 1 14 is electrically biased relative to the chamber body 106, the top electrode 109, and/or the bottom electrode 110, depending upon desired deposition characteristics and aerosol droplet parameters. As a result, the aerosol droplets facilitate film formation on the substrate 113 through adsorption of materials on the substrate 113. The process region 101 is also evacuated by the vacuum pump 117 to remove unreacted aerosol droplets and reaction by-products.

[0033] Figure 2 illustrates a schematic, cross-sectional view of memory device 200 according to an embodiment described herein. The memory device 200, such as a 3D NAND memory device, includes a string 201 of vertically stacked memory cells 220 formed on a semiconductor substrate 202. The string 201 includes a plurality of memory cells 220 alternately disposed between a plurality of vertically spaced insulator layers 210. As shown, the insulator layers 210 and memory cells 220 are formed around a memory hole 203, in which a gate oxide layer 204, a polysilicon channel 205, and a filler material 206 are disposed.

[0034] The semiconductor substrate 202 is any suitable starting material for forming integrated circuits, such as a silicon (Si) substrate or a germanium (Ge) substrate. In certain embodiments, the semiconductor substrate 202 includes a material such as crystalline silicon (e.g., Si<100> or Si<111 >), silicon oxide, strained silicon, silicon germanium, doped or undoped polysilicon, doped or undoped silicon, silicon on insulator (SOI), carbon-doped silicon oxides, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, metal layers disposed on silicon, and the like.

[0035] The gate oxide layer 204 is configured as a shared gate oxide layer for each of memory cells 220 and includes a suitable dielectric material, such as a silicon dioxide material or the like. The filler material 206 is also formed from a dielectric material. In some embodiments, the filler material 206 is the same material as the gate oxide layer 204. The channel 205 is a conductive structure that provides electrons to a charge trap region of each memory cell 220. In some embodiments, the channel 205 includes a doped or undoped polycrystalline silicon material. It is contemplated that methods described herein may be utilized to form either of the gate oxide layer 204 or the filler material 206 in some embodiments, or other similar device structures, depending upon the desired implementation.

[0036] Process conditions can be varied depending on a range of parameters including the type of silicon containing precursor, the type of solvent, total liquid volume, process region temperature, process region pressure, flow rates of the carrier gas, and flow rates of the precursor or precursor solution. In some embodiments, one or more of the following processes or process conditions are used:

[0037] (1 ) The pressure maintained within the process region during deposition is between about 5 Torr and about 700 Torr, such as between about 6 Torr and about 60 Torr (for example, less than about 50 Torr, between about 6 Torr and about 30 Torr, or between about 7 Torr and about 9 Torr), between about 50 Torr and about 200 Torr (for example about 100 Torr).

[0038] (2) A substrate temperature greater than about 10°C, for example between about 15°C and about 500°C, such as between about 15°C and about 450°C, such as between about 50°C and about 200°C, for example about 80°C, about 90°C, about 100°C, about 120°C, or about 150°C. In some embodiments, the substrate temperature is about 100°C or less during deposition, for example between about 50°C and about 90°C.

[0039] (3) A process region temperature greater than about 15°C, for example between about 15°C and about 500°C, such as between about 15°C and about 50 °C, about 80°C, about 100°C, about 120°C, or about 200°C. In some embodiments, the process region temperature is greater than the substrate temperature. Alternately, the substrate temperature is greater than the process region temperature. Alternately, the substrate temperature and the process region temperature are at a temperature or about the boiling point of the solution comprising the silica containing precursor and the solvent.

[0040] (4) A concentration of silicon containing precursor in the precursor solution of greater than about 1 % (w/v), such as between about 10% (w/v) and about 100% (w/v), for example between about 10% (w/v) and about 50% (w/v), such as between about 10% (w/v) and about 30% (w/v).

[0041] (5) A flow rate of the precursor and/or precursor solution of greater than about 0.5 ml/min, such as between about 1 ml/min and about 20 ml/min, for example between about 1 ml/min and about 5 ml/min.

[0042] (6) A flow rate of the carrier gas greater than about 1 slm, such as between about 3 slm and about 5 slm, for example about 4 slm.

[0043] (7) A deposition rate of the polymeric silicon oxide material between about 0.01 pm/min and about 10 pm/min, such as between about 0.01 pm/min and about 5 pm/min, for example between about 0.5 pm/min and about 0.7 pm/min or between about 3 pm/min and about 4 pm/min.

[0044] (8) A deposition time between about 10 minutes and about 120 minutes, such as about 30 minutes to about 120 minutes, for example, about 60 minutes or less, such as about 20 minutes or about 40 minutes..

[0045] (9) Precursors and/or precursor solutions may be delivered to the process chamber through one or more precursor conduits, and one or more

different precursors and/or precursor solutions can be delivered to the process chamber through different precursor conduits.

[0046] (10) An annealing temperature between about 50°C and about 500°C, such as about 350°C or about 400°C. Alternately, the annealing may be performed by exposing the substrate to UV light, or to other heat generation sources in other embodiments. In some embodiments, exposing the substrate to UV light allows the annealing to be performed at low temperatures of greater than about 0°C, such as between about 25°C and about 100°C, for example about 25°C, about 35°C, or about 50°C.

[0047] (11 ) Atomizing the precursor and/or precursor solution at a temperature greater than about 0°C, such as between about 0°C and about 100°C, for example about 15°C or about 25°C.

[0048] Figure 3 illustrates operations of a method 300 for performing an AACVD process according to an embodiment described herein. The method 300 includes preparing a solution of tetraethylorthosilicate (TEOS) and a solvent such as ethanol at operation 310. In this embodiment, the TEOS starting material is a liquid which is mixed with liquid ethanol to form a solution. In another embodiment, other solvents, for example other alcohols (such as methanol, n- propanol, isopropanol), water, and tetrahydrofuran (THF) can be utilized. The solvent solvates the TEOS or the TEOS is dispersed in the solvent.

[0049] In another embodiment, ozone is utilized as a precursor instead of an alcohol. The ozone oxidizes the TEOS in the gas phase. In some embodiments, the oxidation is performed by annealing at a temperature greater than about 350°C. Alternately, oxidation can be performed in the presence of UV light at about 25°C. In some embodiments, argon is injected into the atomizer from a separate port, allowing it to mix with the TEOS. The amount of ozone added is between about 0.05 wt% to about 10 wt%, such as between about 0.1 wt% and about 5 wt%.

[0050] While the description below describes the aerosol from TEOS/ethanol, it is contemplated that TEOS can be used with other solvents as described above.

[0051] A boiling point of the TEOS material is about 168°C and a boiling point of the ethanol is about 78°C. A vapor pressure of TEOS at about 25°C is about 1.5 Torr and a vapor pressure of ethanol at about 25°C is about 70 Torr.

[0052] The TEOS/ethanol solution is atomized at about 25°C to prepare an aerosol at operation 320. In some embodiments, the aerosol is generated by a piezoelectric transducer as described with regard to Figure 1. Alternately, the aerosol may be formed by other methods, such as nebulization, ultrasonic humidification, megasonic humidification, ultrasonic transduction, megasonic transduction, electrostatic nozzle, piezoelectric nozzle, ultrasonic aerosol generation, pneumatic aerosol jet, and electrostatic atomization. It is contemplated that the diameter of droplets within the aerosol are between about 2 nm and about 10 pm, such as between about 2 nm and about 200 nm, depending upon the materials being utilized to form the aerosol and the method of aerosol generation. The aerosol droplet size can be controlled through various ¹ parameters including the type of aerosol generator used (i.e., nebulizer or atomizer), the settings for the aerosol generator, the viscosity and/or concentration of the precursor/precursor solution.

[0053] In some embodiments, the solution and aerosol (i.e., TEOS/ethanol) also include a condensation agent and a catalyst. The condensation agent is a material which functions as a proton donor to catalyze polymerization of a silicon oxide material on a substrate and the catalyst is a material which hydrolyzes TEOS to facilitate polymer linkage in the silicon oxide polymer, such as a silicon dioxide material. In this embodiment, the condensation agent is water and the catalyst is a dilute acid, such as hydrochloric acid (HCI), nitric acid (HN0₃), or sulfuric acid (H₂S0₄). For example, TEOS:ethanol:water may be in a ratio of about 1 :1 :1.33 (by volume), and an amount of acid is added to maintain the pH of

the solution at about 3. In some embodiments, the catalyst is a dilute base, such as ammonium hydroxide (NH₄OH), NaOH, KOH, and organic amine bases such as alkyl amines and aromatic amines. For example, TEOS:ethanol:water may be in a ratio of about 1 :1 :1.33 (by volume), and an amount of base is added to maintain the pH of the solution at about 9.

[0054] At operation 330, the aerosol is delivered to a process chamber, such as the process region 101 of the apparatus 100. The aerosol is delivered along with a nonreactive carrier gas, such as argon, nitrogen, or the like. The carrier gas flows into the aerosol generator and the aerosol droplets are flowed to the process chamber. In some embodiments, once the aerosols flow into the process chamber, the carrier gas is heated up to the temperature of the process chamber. In some embodiments, the process region 101 is maintained at a temperature below the boiling point of ethanol, for example, from about 15°C to about 50°C, to prevent premature vaporization of the ethanol prior to deposition of the silicon oxide polymer on the substrate 113. It is believed that by maintaining the process region 101 at a temperature of less than the ethanol boiling point, flowability of a deposited layer is maintained. In this embodiment, the substrate 1 13 is maintained at a temperature greater than the boiling point of ethanol, for example, about 150°C. By maintaining the substrate 113 at a temperature greater than the boiling point of the ethanol, the ethanol is vaporized and silicon oxide material polymerization is promoted to deposit an SiO_x polymer material on the substrate 113. Byproducts, including ethanol, are removed to the reactor exhaust. Alternately, both the temperature of the process region 101 and the substrate 1 13 may be maintained at a temperature greater than a boiling point of the ethanol.

[0055] The pressure maintained within the process region 101 during deposition is between about 5 Torr and about 700 Torr, for example, between about 6 Torr and about 30 Torr, such as about 7 Torr or about 9 Torr. The deposition process is performed for a time sufficient to fill gaps on the

substrate 1 13, such as gaps up to about 3 pm deep. In some embodiments, the deposition time is between about 30 minutes and about 120 minutes, for example, about 60 minutes or less, such as about 20 minutes or about 40 minutes. At operation 340, a SiO_x polymeric material is deposited on the substrate 113. Reaction byproducts, which include hydrocarbon gases, such as ethylene, are also exhausted from the process region 101 during operation 340 using vacuum pump 117. In some embodiments, the deposition rate of the SiO_x polymeric material is between about 0.5 pm/min and about 0.7 pm/min. It is also believed that shrinkage of the deposited SiO_x polymeric material is less than about 1 %, which substantially reduces or prevents the probability of cracks or voids in the gap fill material.

[0056] The aerosolized materials exhibit liquid like behavior as the materials adsorb on the substrate 113. The liquid like behavior, or flowability, of the materials is influenced by the vapor pressure of the ethanol which allows the materials to“flow” like a liquid even though they are in a gas like phase. The vapor pressure of the ethanol can be controlled by the temperature and the pressure of the process chamber. In this manner, SiO_x polymeric materials exhibit substantially void free bottom-up gap fill characteristics while reducing deposited overburden of material outside of the gaps.

[0057] After deposition of the SiO_x polymeric material, the material may optionally be annealed to densify the material, which increases a wet etch rate of the material during subsequent etching processes. In some embodiments, the material is annealed at a temperature of about 60°C for about 30 minutes. The annealing may be performed by exposing the substrate 113 to ultraviolet (UV) light in some embodiments, or to other heat generation sources in other embodiments. Exposing the substrate 113 to UV light allows the annealing to be performed at low temperatures of between about 25°C and about 100°C, for example about 50°C.

[0058] Figure 4 illustrates operations of a method 400 for performing an AACVD process according to an embodiment described herein. The method 400 includes preparing a mixture of hydrogen silsesquioxane (HSQ, [HSi0_3/2]_n) and methyl isobutyl ketone (MIBK) at operation 410. While the description below describes the aerosol from HSQ/MIBK, it is contemplated that HSQ can be used with other solvents such as acetone and tetrahydrofuran.

[0059] The HSQ starting material is mixed with liquid MIBK to form a solution. The MIBK functions to either solvate the HSQ or the HSQ is dispersed in the MIBK. A boiling point of MIBK is about 117°C.

[0060] The HSQ/MIBK mixture is atomized at about 25°C to prepare an aerosol at operation 420. In some embodiments, the aerosol is generated by a piezoelectric transducer as described with regard to Figure 1. Alternately, the aerosol may be formed by other methods such as nebulization, ultrasonic humidification, megasonic humidification, ultrasonic transduction, megasonic transduction, electrostatic nozzle, piezoelectric nozzle, ultrasonic aerosol generation, pneumatic aerosol jet, and electrostatic atomization. It is contemplated that a diameter of droplets within the aerosol are between about 2 nm and about 10 pm, such as between about 2 nm and about 200 nm, depending upon the materials being utilized to form the aerosol and the method of aerosol generation. The aerosol droplet size can be controlled through various parameters including the type of aerosol generator used {i.e., nebulizer or atomizer), the settings for the aerosol generator, the viscosity and/or concentration of the precursor/precursor solution.

[0061] At operation 430, the aerosol is delivered to a process chamber, such as the process region 101 of the apparatus 100. The aerosol is delivered along with a nonreactive carrier gas, such as argon, nitrogen, or the like. In some embodiments, the process region 101 is maintained at a temperature of about 120°C to promote volatilization of the MIBK. In this embodiment, the substrate 113 is maintained at a temperature of up to about 450°C. By

maintaining the substrate 113 at a temperature greater than the temperature of the process region 101 , the MIBK is volatilized and silicon oxide material polymerization is promoted to deposit an SiO_x polymer material on the substrate 113.

[0062] The pressure maintained within the process region 101 during deposition is between about 5 Torr and about 700 Torr, for example, between about 6 Torr and about 60 Torr, such as less than about 50 Torr. The deposition process is performed for a time sufficient to fill gaps on the substrate 113, such as gaps up to about 3 pm deep. In some embodiments, the deposition time is between about 60 minutes or less, such as about 20 minutes or about 40 minutes. At operation 440, a SiO_x polymeric material is deposited on the substrate 113. Reaction byproducts, which include H₂, are also exhausted from the process region 101 during operation 440. In some embodiments, a deposition rate of the SiO_x polymeric material is between about 3 pm/min and about 4 pm/min. It is also believed that shrinkage of the deposited SiO_x polymeric material is less than about 1 %, which substantially reduces or prevents the probability of cracks or voids in the gap fill material.

[0063] Similar to the TEOS/ethanol embodiment, the aerosolized HSQ/MIBK materials exhibit liquid like flowability as the materials adsorb on the substrate 113. In this manner, SiO_x polymeric materials exhibit substantially void free bottom-up gap fill characteristics while reducing overburden of material deposited outside of the gaps. After deposition of the SiO_x polymeric material, the material may optionally be annealed, as described above.

[0064] Figure 5 illustrates operations of a method 500 for performing an AACVD process according to an embodiment described herein. The method 500 includes preparing a solution of 1-methylsilanetriol (MST) and water at operation 510. In this embodiment, the MST starting material is mixed with liquid water to form a solution, such as about a 30% (w/v) MST:water aqueous solution. A boiling point of the solution is about 201 °C and a vapor pressure of the solution

is about 0.0787 Torr at about 25°C. While the description below describes the aerosol from MST/water, it is contemplated that MST can be used with other solvents, such as methanol, ethanol, n-propanol, or isopropanol.

[0065] The MST/water solution is atomized at about 25°C to prepare an aerosol at operation 520. In some embodiments, the aerosol is generated by a piezoelectric transducer as described with regard to Figure 1. Alternately, the aerosol may be formed by other methods, such as nebulization, ultrasonic humidification, megasonic humidification, ultrasonic transduction, megasonic transduction, electrostatic nozzle, piezoelectric nozzle, ultrasonic aerosol generation, pneumatic aerosol jet, and electrostatic atomization. It is contemplated that the diameter of droplets within the aerosol are between about 2 nm and about 10 pm, such as between about 2 nm and about 200 nm, depending upon the materials being utilized to form the aerosol and the method of aerosol generation. The aerosol droplet size can be controlled through various parameters including the type of aerosol generator used (/.e., nebulizer or atomizer), the settings for the aerosol generator, the viscosity and/or concentration of the precursor/precursor solution.

[0066] At operation 530, the aerosol is delivered to a process chamber, such as the process region 101 of the apparatus 100. The aerosol is delivered along with a nonreactive carrier gas, such as argon, nitrogen, or the like. In some embodiments, the process region 101 is maintained at a temperature about equal to a boiling point of the solution, such as about 200°C, to promote volatilization of the water from the aerosolized solution. In this embodiment, the substrate 113 is maintained at a temperature of about 150°C.

[0067] The pressure maintained within the process region 101 during deposition is between about 5 Torr and about 700 Torr, for example, between about 50 Torr and about 200 Torr, such as about 100 Torr. The deposition process is performed for a time sufficient to fill gaps on the substrate 113, such as gaps up to about 3 pm deep. In some embodiments, the deposition time is

between about 60 minutes or less, such as between about 20 minutes and about 40 minutes, for example, about 30 minutes. At operation 540, an SiO_x polymeric material is deposited on the substrate 1 13. Reaction byproducts, which include CH₄ and H₂, are also exhausted from the process region 101 during operation 540. It is believed that shrinkage of the deposited SiO_x polymeric material is less than about 1 %, which substantially reduces or prevents the probability of cracks or voids in the gap fill material.

[0068] Similar to the TEOS/ethanol and HSQ/MIBK embodiments, the aerosolized MST/water materials exhibit liquid like flowability as the materials adsorb on the substrate 113. In this manner, SiO_x polymeric materials exhibit substantially void free bottom-up gap fill characteristics while reducing overburden of material deposited outside of the gaps. After deposition of the SiO_x polymeric material, the material may optionally be annealed, as described above.

[0069] Figure 6 illustrates operations of a method 600 for performing an AACVD process according to an embodiment described herein. The method 600 includes atomizing a silicon containing liquid precursor at about 25°C to form an aerosol at operation 610. In some embodiments, the silicon containing liquid precursor is SiCI₄. In another embodiment, the silicon containing liquid precursor is a volatile methylsilane (VMS) material. In another embodiment, the silicon containing liquid precursor is a cyclic siloxane material.

[0070] In some embodiments, the aerosol is generated by a piezoelectric transducer as described with regard to Figure 1. Alternately, the aerosol may be formed by other methods, such as nebulization, ultrasonic humidification, megasonic humidification, ultrasonic transduction, megasonic transduction, electrostatic nozzle, piezoelectric nozzle, ultrasonic aerosol generation, pneumatic aerosol jet, and electrostatic atomization. It is contemplated that the diameter of droplets within the aerosol are between about 2 nm and about 10 pm, such as between about 2 nm and about 200 nm, depending upon the

materials being utilized to form the aerosol and the method of aerosol generation. The aerosol droplet size can be controlled through various parameters including the type of aerosol generator used (i.e., nebulizer or atomizer), the settings for the aerosol generator, the viscosity and/or concentration of the precursor/precursor solution.

[0071] At operation 620, the aerosol of the silicon containing liquid precursor is delivered to a process chamber along with an oxidant. In some embodiments, the oxidant is water. In another embodiment, the oxidant is ozone. In another embodiment, the oxidant is a hydroxyl radical material. At operation 630, a silicon oxide material is deposited on a substrate.

[0072] The aerosolized materials exhibit liquid like flowability as the materials adsorb on the substrate 113. In this manner, SiO_x polymeric materials exhibit substantially void free bottom-up gap fill characteristics while reducing overburden of material deposited outside of the gaps. After deposition of the SiO_x polymeric material, the material may optionally be annealed, as described above.

[0073] Figure 7 illustrates operations of a method 700 for performing an AACVD process according to an embodiment described herein. The method 700 includes preparing a solution of silica nanoparticle and solvent (for example, an alcohol solvent such as methanol, ethanol, n-propanol, and isopropanol) at operation 705. The silica nanoparticle has a particle size of greater than 1 nm, for example between about 5 nm and about 30 nm, such as between about 5 nm and about 15 nm. In some embodiments, the concentration of silica nanoparticle to solvent is greater than about 1 % (w/v), such as between about 1 % (w/v) to about 50% (w/v), for example about 10% (w/v). Alternately, the solution is silica nanoparticle in water.

[0074] The solution is atomized at about 25°C to prepare an aerosol at operation 710. In some embodiments, the aerosol is generated by a

piezoelectric transducer as described with regard to Figure 1. Alternately, the aerosol may be formed by other methods, such as nebulization, ultrasonic humidification, megasonic humidification, ultrasonic transduction, megasonic transduction, electrostatic nozzle, piezoelectric nozzle, ultrasonic aerosol generation, pneumatic aerosol jet, and electrostatic atomization. It is contemplated that the diameter of droplets within the aerosol are between about 2 nm and about 10 pm, such as between about 2 nm and about 200 nm, depending upon the materials being utilized to form the aerosol and the method of aerosol generation. The aerosol droplet size can be controlled through various parameters including the type of aerosol generator used (/.e., nebulizer or atomizer), the settings for the aerosol generator, the viscosity and/or concentration of the precursor/precursor solution.

[0075] At operation 715, the aerosol is delivered to a process chamber, such as the process region 101 of the apparatus 100. The aerosol is delivered along with a nonreactive carrier gas, such as argon, nitrogen, or the like. In some embodiments, the process region 101 is maintained at a temperature about equal to or greater than a boiling point of the solution, such as about 78°C (ethanol) or about 100°C (water), to promote volatilization of the water from the aerosolized solution. In this embodiment, the substrate 1 13 is maintained at a temperature of greater than about 15°C, such as between about 15°C and about 450°C, for example about 90°C, 100°C, or 150°C.

[0076] The pressure maintained within the process region 101 during deposition is between about 5 Torr and about 700 Torr, for example, between about 50 Torr and about 200 Torr, such as about 100 Torr. The deposition process is performed for a time sufficient to fill gaps on the substrate 1 13, such as gaps up to about 3 pm deep. In some embodiments, the deposition time is between about 60 minutes or less, such as between about 20 minutes and about 40 minutes, for example, about 30 minutes. At operation 720, an SiO_x polymeric material is deposited on the substrate 113. Reaction byproducts are also

exhausted from the process region 101 during operation 720. It is believed that shrinkage of the deposited SiO_x polymeric material is less than about 1 %, which substantially reduces or prevents the probability of cracks or voids in the gap fill material.

[0077] The aerosolized materials exhibit liquid like flowability as the materials adsorb on the substrate 1 13. In this manner, SiO_x polymeric materials exhibit substantially void free bottom-up gap fill characteristics while reducing overburden of material deposited outside of the gaps. After deposition of the SiO_x polymeric material, the material may optionally be annealed, as described above.

[0078] In summation, embodiments described herein provide for deposition of gap fill materials in high aspect ratio gaps with improved flowability and efficiency. Accordingly, overburden of deposited material is substantially reduced or prevented and void free or substantially void free deposition can be achieved. As a result, overburden removal processes are eliminated and substantially defect free gap fill materials may be realized.

[0079] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1. A substrate processing method, comprising:

delivering an aerosol to a process region, the aerosol formed from a solution of a silica nanoparticle and a solvent;

maintaining a temperature of the process region at a temperature less than a boiling point of the solvent;

maintaining a temperature of a substrate at a temperature greater than a boiling point of the solvent; and

depositing a polymeric silicon oxide material on the substrate.

2. The method of claim 1 , wherein the aerosol is formed by piezoelectric transduction.

3. The method of claim 1 , wherein the aerosol is formed by ultrasonic humidification.

4. The method of claim 1 , wherein the aerosol is delivered to the process region with a nonreactive carrier gas.

5. The method of claim 1 , wherein the solvent is an alcohol or water.

6. The method of claim 1 , wherein the silica nanoparticle has a particle size between about 5 nm and about 15 nm.

7. The method of claim 1 , wherein the temperature of the process region is maintained between about 15°C and about 50°C.

8. The method of claim 1 , wherein the polymeric silicon oxide material is deposited at a rate of between about 0.01 pm/min and about 5 pm/min.

9. The method of claim 1 , wherein a pressure maintained within the process region during deposition of the polymeric silicon oxide material is between about 5 Torr and about 700 Torr.

10. A substrate processing method, comprising:

delivering an aerosol to a process region, the aerosol formed from a solution of tetraethylorthosilicate, ethanol, water, and catalyst;

maintaining a temperature of the process region at a temperature less than a boiling point of the ethanol;

maintaining a temperature of a substrate at a temperature greater than a boiling point of ethanol; and

depositing a polymeric silicon oxide material on the substrate.

11. The method of claim 10, wherein the aerosol is formed by piezoelectric transduction, ultrasonic humidification, or nebulization.

12. The method of claim 10, wherein a pressure maintained within the process region during deposition of the polymeric silicon oxide material is between about 5 Torr and about 700 Torr.

13. The method of claim 12, wherein the temperature of the process region is between about 15°C and about 50°C, and the temperature of the substrate is between about 100°C and about 150°C.

14. The method of claim 13, wherein the polymeric silicon oxide material is deposited at a rate of between about 0.01 pm/min and about 5 pm/min.

15. A substrate processing method, comprising:

delivering an aerosol to a process region, the aerosol formed from a solution of 1-methylsilanetriol and a solvent selected from water, methanol, ethanol, isopropanol; maintaining a temperature of the process region at a temperature about equal to a boiling point of the solution;

maintaining a temperature of a substrate at a temperature less than the temperature of the process region and the boiling point of the solution;

maintaining the process region at a pressure between about 50 Torr and about 200 Torr;

depositing a polymeric silicon oxide material on the substrate; and

annealing the polymeric silicon oxide material.