Methods and systems for forming patterned structures using multiple patterning processes

Abstract

Methods of forming patterned structures and manipulating film characteristics suitable for multiple patterning processes are disclosed. An exemplary method includes forming a layer overlying a substrate, followed by processing the layer, where the layer is formed by providing a precursor to a reaction chamber for a precursor pulse period, providing a reactant to the reaction chamber for a reactant pulse period, applying a first plasma power having a first frequency within a first plasma power period, and optionally applying a second plasma power having a second frequency within a second plasma power period. A second plasma power having a second frequency is applied within a second plasma power period, wherein the first frequency is different from the second frequency. The example method may further include the step of processing the deposited material.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a continuation-in-part of U.S. application No. 17 / 410,983, filed on August 24, 2021, entitled “METHOD AND SYSTEM FOR FORMINGPATTERNED STRUCTURES USING MULTIPLE PATTERNING PROCESS,” which claims the benefit and priority of U.S. application No. 63 / 070,950 of the same title filed in the U.S. Patent and Trademark Office on August 27, 2020, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure generally relates to methods and systems for forming patterned structures on a substrate surface. More specifically, examples of the present disclosure relate to methods and systems that can be used to form patterned structures suitable for a multiple patterning process. Background Art

[0004] In the manufacture of electronic devices, fine patterns of features can be formed on a substrate surface by patterning the substrate surface and removing material from the substrate surface using, for example, wet etching and / or dry etching processes. Photoresists are often used for such patterning of the substrate surface.

[0005] A photoresist pattern can be formed by coating a photoresist layer on a substrate surface, masking the surface of the photoresist, exposing an unmasked portion of the photoresist to radiation, such as ultraviolet light or an electron beam, and removing a portion of the photoresist (e.g., an unmasked or masked portion) while leaving a portion of the photoresist on the substrate surface (e.g., another portion of the unmasked or masked portion). Once the photoresist is patterned, the patterned photoresist can be used as a template for etching the material on the substrate surface in the area where the photoresist is removed to form a transferred pattern in the layer below the photoresist. After etching, the remaining photoresist can be removed.

[0006] As device sizes decrease, conventional photoresist techniques may not be suitable for forming patterns of the required size. In such cases, multiple patterning techniques may be used to allow patterning and etching of features smaller than the exposure resolution of the photolithography process. The multiple patterning process may include forming spacers around patterned features (e.g., patterned photoresist), removing the patterned features to form a patterned structure, and using the patterned structure as a mask during subsequent etching.

[0007] Although these techniques may work relatively well in some applications, once the patterned features are removed, the patterned structures may deviate from a vertical position or tilt. The tilt of the patterned structures can cause undesirable changes in subsequent etching steps and the resulting pattern transfer. This becomes increasingly problematic as the size of the patterned structures decreases.

[0008] Therefore, there is a need for an improved method of forming a patterned structure on a substrate surface. In addition, there is a need for a device structure including the patterned structure. And, a system for performing the method is also desired.

[0009] Any discussion of problems and solutions set forth in this section has been included in the present disclosure merely to provide context for the present disclosure, and should not be considered an admission that any or all of the discussion was known at the time the present invention was made. Summary of the invention

[0010] Various embodiments of the present disclosure relate to methods of forming a patterned structure on a substrate surface and systems for forming a patterned structure. The patterned structure can be used to form devices, such as semiconductor devices and other electronic devices.

[0011] Although the manner in which various embodiments of the present disclosure address the shortcomings of existing methods and systems is discussed in more detail below, in general, various embodiments of the present disclosure provide improved methods for forming patterned structures having desired (e.g., mechanical) properties on a substrate surface. The patterned structures may have a relatively high hardness, exhibit relatively low stress, and / or exhibit a relatively low etch rate. Due to their one or more desired properties, patterned structures according to examples of the present disclosure may be relatively short, thereby allowing relatively accurate pattern transfer when etching the underlying layer.

[0012] According to an example of the present disclosure, a method for forming a patterned structure using a multiple patterning process is disclosed. The method includes providing a substrate in a reaction chamber and forming a layer covering the substrate. The substrate includes a surface containing patterned features. The step of forming a layer may include providing a precursor to the reaction chamber in a precursor pulse period, providing a reactant to the reaction chamber in a reactant pulse period, and applying at least one of a first plasma power having a first frequency less than 1MHz in a first plasma power period and a second plasma power having a second frequency in a second plasma power period, wherein the first frequency is different from the second frequency. As described in more detail below, the step of providing a reactant to the reaction chamber in a reactant pulse period may be performed continuously in one or more other steps of the method and / or in one or more deposition cycles. The first frequency may be different from (e.g., lower than) the second frequency. According to an example of the present disclosure, the first frequency is less than 1MHz (e.g., between about 300kHz and about 500kHz). According to an example of the present disclosure, the step of applying a first plasma power and the step of applying a second plasma power overlap. In some cases, the step of applying the first or second plasma power may be omitted. According to a further example, the step of forming a layer includes a cyclic deposition process. According to further examples, the reactant pulse period overlaps with one or more of the first plasma power period and the second plasma power period. In at least some cases, the precursor pulse period does not overlap with one or more of the first plasma power period and the second plasma power period. According to another exemplary embodiment of the present disclosure, the method includes a step of providing an inert gas during the step of providing a reactant to the reaction chamber in the reactant pulse period. The ratio of inert gas to reactant is greater than or equal to 2. When the ratio of inert gas to reactant is greater than or equal to 2, desired mechanical properties (such as hardness and low stress) can be maintained. Additionally or alternatively, the inert gas can be greater than 3slm or provided to the reaction chamber at a flow rate greater than 3slm and about 6slm. During one or more cycles of the formation step, the pressure in the reaction chamber can be greater than 400Pa, or between greater than 400Pa and about 500Pa, or about 450±50pa. In some cases, the pressure can be between about 100Pa and about 500Pa or between about 200Pa and about 400Pa.

[0013] The method may also include a step of treating the deposited material. The step of treating the deposited material may include providing an oxygen-free gas to the reaction chamber and applying a third plasma power within a third plasma power cycle to form an active substance from the oxygen-free gas to treat the deposited material, thereby forming a treated material. As discussed in more detail below, this treatment is used to produce a patterned structure with desired (e.g., increased) mechanical strength and (e.g., reduced or relaxed) stress, which allows the pattern to be more accurately transferred from the patterned structure to the underlying layer. As described below, the steps of forming the layer and treating the deposited material can be repeated at various ratios to obtain the desired characteristics of the patterned structure. According to examples of these embodiments, the amount of Si-Si bonds in the treated material is greater than the amount of Si-Si bonds in the deposited material. Additionally or alternatively, the amount of carbon in the treated material may be less than the amount of carbon in the deposited material.

[0014] The layer, deposited material, or processed material may be or include, for example, a nitride or oxide, such as a metal oxide, silicon oxide, silicon metal oxide, metal nitride, silicon nitride, or metal silicon nitride. As discussed in more detail below, one or more (e.g., mechanical) properties of the layer and / or patterned features may be manipulated by one or more of: manipulating the inert gas: reactant flow ratio to the reaction chamber, manipulating the power of the first plasma power (e.g., LRF) and / or the second plasma power, manipulating the inert gas flow, manipulating the pressure within the reaction chamber, manipulating the duration of the first plasma power, and / or manipulating the conditions of the processing steps, such as the ratio of the deposition step to the processing step, the plasma power during the processing step, and the duration of the plasma power during the processing step.

[0015] According to a further embodiment of the present disclosure, a device structure is provided. The device structure may be formed according to the method described herein. The device structure may include a substrate and one or more patterned structures formed thereon or therein.

[0016] According to a further example of the present disclosure, a device is formed using the device structure as described herein.

[0017] According to further examples of the present disclosure, a system is provided, the system being configured to perform the methods described herein and / or form a device structure.

[0018] These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments, which proceeds by reference to the attached figures; the invention is not limited to any particular embodiment disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A more complete understanding of exemplary embodiments of the present disclosure may be obtained by referring to the detailed description and claims when considered in conjunction with the following illustrative drawings.

[0020] Figure 1 A method in accordance with at least one embodiment of the present disclosure is shown.

[0021] Figure 2 A timing sequence is shown in accordance with at least one embodiment of the present disclosure.

[0022] Figures 3 to 7 The structure of an exemplary embodiment according to the present disclosure is shown.

[0023] Figure 8 A system in accordance with at least one embodiment of the present disclosure is shown.

[0024] Fig. 9 Hardness and stress values ​​for layers formed according to examples of the present disclosure are shown.

[0025] Fig.10 Hardness and stress values ​​for layers formed according to additional examples of the present disclosure are shown.

[0026] Fig.11 A film deposited on a patterned feature is shown.

[0027] Fig.12 Another timing sequence suitable for forming layers according to additional embodiments of the present disclosure is shown.

[0028] Figures 13 to 18 , Fig. 20A , Fig. 20B , Fig.21 and Fig. 22 Compositions and / or properties of layers formed according to exemplary embodiments of the present disclosure are shown.

[0029] Fig.19 Deposited layers according to an exemplary embodiment of the present disclosure are shown.

[0030] Fig.23 and Fig.24 Patterned feature thickness and elastic modulus as a function of CK are shown according to further exemplary embodiments of the present disclosure.

[0031] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0032] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0033] The present disclosure generally relates to methods for forming patterned structures on substrate surfaces, device structures including patterned structures, and systems for performing the methods and / or forming device structures. As described in more detail below, exemplary methods can be used to form device structures suitable for forming electronic devices. For example, exemplary methods can be used to form patterned structures on substrate surfaces. The patterned structures can be used as etching masks or patterned features to form the next set of patterned structures.

[0034] As described in more detail below, exemplary methods and systems may be used to form patterned structures having desired characteristics, which allows for more precise pattern transfer, more reliable device fabrication, formation of smaller or larger pitch etch patterns, and more reliable device performance.

[0035] In the present disclosure, a gas may include a material that is a gas at normal temperature and pressure, a evaporated solid, and / or an evaporated liquid, and may be composed of a single gas or a gas mixture as appropriate. Gases other than process gases, such as gases introduced without passing through a gas distribution assembly (e.g., a showerhead, other gas distribution devices, etc.), may be used, for example, to seal a reaction space, and may include sealing gases, such as rare gases or other inert gases. The term inert gas refers to a gas that does not participate in a chemical reaction to a sensible degree and / or a gas that can excite a precursor when plasma power is applied. In some cases, the terms precursor and reactant may be used interchangeably.

[0036] As used herein, the term "substrate" may refer to any one or more underlying materials that may be used to form or on which a device, circuit, or film may be formed. A substrate may include a bulk material, such as silicon (e.g., single crystal silicon), other Group IV materials, such as germanium, or a compound semiconductor material, such as GaAs, and may include one or more layers overlying or underlying the bulk material. In addition, the substrate may include various features, such as grooves, lines, etc., formed in or on at least a portion of the substrate layer. As a specific example, the substrate may include a bulk semiconductor material and / or a layer to be etched.

[0037] In some embodiments, a film refers to a layer extending in a direction perpendicular to the thickness direction to cover the entire target or relevant surface, or a layer that only covers the target or relevant surface. In some embodiments, a layer refers to a structure with a certain thickness formed on a surface, or a synonym for a film or non-film structure. A layer may be continuous or discontinuous. A film or layer may be composed of a discrete single film or layer or multiple films or layers with certain properties, and the boundaries between adjacent films or layers may or may not be clear, and may or may not be established based on physical, chemical and / or any other properties, formation process or sequence and / or the function or purpose of adjacent films or layers.

[0038] In the present disclosure, continuous can refer to one or more of the following: without breaking vacuum, without being a timeline interruption, without any material intervening step, without changing processing conditions, immediately following, as the next step, or without intervening discrete physical or chemical structures between two structures except for two structures in some embodiments. For example, during two or more steps and / or deposition cycles of a method, reactants and / or inert gases can be continuously supplied.

[0039] The term "cyclic deposition process" or "cyclic deposition process" may refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber and / or pulsing of plasma power therein to deposit layers on a substrate, and includes process techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), hybrid cyclic deposition processes including an ALD component and a cyclic CVD component, and plasma-enhanced variants thereof.

[0040] As used herein, the term atomic layer deposition (ALD) may refer to a vapor deposition process in which a deposition cycle, preferably a plurality of continuous or continuous deposition cycles, is performed in a processing chamber. Typically, during each cycle, a precursor is introduced and the precursor may be chemically adsorbed to a deposition surface (e.g., a substrate surface or a previously deposited underlying surface, such as a material from a previous ALD cycle) to form a monolayer or sub-monolayer that is not easily reacted with additional precursors (i.e., a self-limiting reaction). Thereafter, a reactant (e.g., another precursor or a reactive gas) may be subsequently introduced into the processing chamber for converting the chemically adsorbed precursor into the desired material on the deposition surface. Typically, the reactant is capable of further reacting with the precursor. In addition, a purge step may also be used during each cycle to remove excess precursor from the processing chamber and / or remove excess reactants and / or reaction byproducts from the processing chamber after the chemically adsorbed precursor is converted. Furthermore, as used herein, the term atomic layer deposition is also meant to include processes designated by related terms, such as chemical vapor atomic layer deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE or organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of a precursor composition, a reactive gas, and a purge gas (e.g., an inert carrier gas). PEALD refers to an ALD process in which a plasma is applied during one or more ALD steps.

[0041] As used herein, the term "purge" may refer to the process of providing an inert or substantially inert gas to a reactor chamber between two mutually reacting gas pulses. For example, a purge may be provided between a precursor pulse and a reactant pulse to avoid or at least reduce gas phase interactions between the precursor and the reactant. It should be understood that the purge may be performed in time or space, or both. For example, in the case of a time purge, a purge step may be used, such as in a time sequence of providing a first precursor to a reaction chamber, providing a purge gas to the reaction chamber, and providing a second precursor to the reaction chamber, wherein the substrate on which the layer is deposited does not move. For example, in the case of a space purge, the purge step may take the form of moving the substrate from a first position where the first precursor is supplied to a second position where the second precursor is supplied through a purge gas curtain.

[0042] As used herein, silicon oxide refers to a material comprising silicon and oxygen. Silicon oxide can be represented by the formula SiO2. In some cases, silicon oxide may not be or include stoichiometric silicon oxide. In some cases, silicon oxide may include other elements, such as carbon, nitrogen, hydrogen, etc.

[0043] As used herein, silicon nitride refers to a material comprising silicon and nitrogen. Silicon nitride can be represented by the formula Si3N4. In some cases, silicon nitride may not be or include stoichiometric silicon nitride. In some cases, silicon nitride may include other elements, such as carbon, nitrogen, hydrogen, etc.

[0044] As used herein, metal oxide refers to a material comprising at least one metal and oxygen. The metal oxide can be represented by the formula MO x , wherein M represents a metal (e.g., TiO2). In some cases, the metal oxide may not be or include a stoichiometric metal oxide. In some cases, the metal oxide may include other elements, such as carbon, nitrogen, hydrogen, etc. Exemplary metals include titanium.

[0045] As used herein, metal nitride refers to a material comprising at least one metal and nitrogen. The metal nitride can be represented by the formula MN x (e.g., TiN), where M can be one or more metals. In some cases, the metal nitride may not be or include a stoichiometric metal nitride. In some cases, the metal nitride may include other elements, such as carbon, nitrogen, hydrogen, etc. Exemplary metals include titanium.

[0046] Silicon metal oxide can be a metal oxide that can additionally contain silicon. Silicon metal oxide can be represented by the formula Si x M (1-x) O y Represented, wherein M represents at least one metal element, x is less than 1, including 0, y is about 2 or a stoichiometrically determined number, wherein M is a metal, such as titanium.

[0047] Silicon metal nitride may be a metal nitride that may additionally contain silicon. Silicon metal nitride may be of the formula Si x M (1-x) N y It represents, wherein M represents at least one metal element, x is less than 1, including 0, and y is a suitable or stoichiometrically determined number. M can be or include, for example, titanium.

[0048] As used herein, the term "overlap" may refer to coincidence in time and within a reaction chamber. For example, when two or more plasma power cycles overlap, there is a time period during which power from each of the two or more plasma power cycles is supplied to the reaction chamber. Similarly, with respect to gas pulse cycles, such as precursor pulse cycles and reactant pulse cycles, two or more gas pulse cycles may overlap when gas from the corresponding pulse cycles is within the reaction chamber or supplied to the reaction chamber for a period of time.

[0049] In addition, in the present disclosure, any two numbers of a variable may constitute a feasible range for the variable, and any range indicated may include or exclude endpoints. In addition, any values ​​of the indicated variables (regardless of whether they are indicated with about) may refer to exact values ​​or approximate values, and include equivalents, and in some embodiments may refer to average values, medians, representative values, majority values, etc. In addition, in the present disclosure, the terms include, include, consist of, and have may independently refer to generally or broadly include, consist of, or consist of in some embodiments. In the present disclosure, the meaning of any definition does not necessarily exclude the common and customary meanings in some embodiments.

[0050] Now turning to the attached figure, Figure 1 A method 100 of forming a patterned structure (e.g., using a multiple patterning process) according to an example of the present disclosure is shown. The method 100 includes the steps of providing a substrate within a reaction chamber (step 102), forming a layer covering the substrate (step 104), removing a portion of the layer (step 106), removing the patterned features (step 108), and etching the bottom layer (step 110). As discussed in more detail below, the exemplary method may also include the step of processing the deposited material (e.g., the material deposited during step 104). Although illustrated with steps 102-110, the exemplary method need not include all of these steps, but may include any subset of these steps.

[0051] During step 102, a substrate including a surface having patterned features is provided within a reaction chamber of a reactor system. Figure 3 An exemplary substrate 300 used during step 102 is shown in FIG. In this example, the substrate (device structure) includes a first layer or bulk material 304, a second layer 306 (e.g., a layer to be etched), and a surface 302 including patterned features 308-312. The first layer or bulk material 304 may include, for example, silicon or other semiconductor materials; the second layer 306 may include, for example, one or more materials having an etch selectivity relative to the material used to form the features 308-312 and layer 402, and the patterned features 308-312 may include, for example, one or more of a photoresist, a carbon hard mask material, amorphous silicon, amorphous carbon, or polycrystalline silicon.

[0052] Back again Figure 1 The reaction chamber used during step 102 may be or include a reaction chamber of a chemical vapor deposition reactor system configured to perform a cyclic deposition process. The reaction chamber may be a stand-alone reaction chamber or part of a combination tool.

[0053] Step 102 may include heating the substrate to a desired deposition temperature within the reaction chamber. In some embodiments of the present disclosure, step 102 includes heating the substrate to a temperature below 800°C. For example, in some embodiments of the present disclosure, heating the substrate to the deposition temperature may include heating the substrate to a temperature between about 50°C and about 300°C, or between about 20°C and about 100°C, or between about 40°C and about 80°C. In addition to controlling the temperature of the substrate, the pressure within the reaction chamber may also be adjusted. For example, in some embodiments of the present disclosure, during step 102, the pressure within the reaction chamber may be less than 760 Torr, or between 0.2 Torr and 760 Torr, or between about 1.5 Torr and 10 Torr. In some cases, during step 102 and / or step 104, the pressure within the reaction chamber is greater than 400Pa, or between greater than 400Pa and about 500Pa, or between about 450±50Pa, or between about 100Pa and about 500Pa, or between about 200Pa and about 400Pa.

[0054] During step 104, a layer (eg, Figure 4 Layer 402 is shown as a layer 402. Layer 402 may be or include, for example, a nitride or an oxide, such as a metal oxide, silicon oxide, silicon metal oxide, metal nitride, silicon nitride, or silicon metal nitride. Due to the desired properties of layer 402, layer 402 may be relatively thin, for example, less than about 20 nm. Specifically, as described below in conjunction with Fig. 9 and 10 Discussed in more detail, layer 402 can have relatively low stress and relatively high hardness, which allows for the formation of patterned structures or layer 402 having relatively low thickness. Additionally, layer 402 can exhibit high etch selectivity compared to typical films used to form patterned structures.

[0055] Step 104 may include depositing material, and in at least some cases, processing the deposited material. According to an example of the present disclosure, the step of depositing material includes providing a precursor to a reaction chamber during a precursor pulse period, providing a reactant to the reaction chamber during a reactant pulse period, and applying at least one of a first plasma power having a first frequency of less than 1 MHz during a first plasma power period and a second plasma power having a second frequency during a second plasma power period, wherein the first frequency is different from the second frequency. The pressure and / or temperature during step 104 may be the same or similar to the temperature set forth in conjunction with step 102.

[0056] As used herein, pulse period refers to the period of gas (e.g., precursor, reactant, inert gas and / or carrier gas) flow to the reaction chamber and / or the period of power application (e.g., power to generate plasma). The height and / or width of the pulse period shown does not necessarily represent a specific amount or duration of the pulse.

[0057] Figure 2 An exemplary timing sequence 200 for step 104 suitable for forming a layer covering a substrate is shown. In the example shown, a precursor is provided to a reaction chamber during a precursor pulse period 212, a reactant is provided to the reaction chamber during a reactant pulse period 204, a first plasma power (e.g., having a frequency of less than 1 MHz) is applied during a first plasma power period 214 to form a plasma, and optionally, a second plasma power having a second frequency is applied during a second plasma power period. The second frequency can be higher (e.g., between about 13 MHz and about 14 MHz or between about 26 MHz and about 28 MHz) than the first frequency (less than 1 MHz or, for example, between about 300 kHz and about 500 kHz). As shown, the sequence 200 can include one or more deposition cycles 218; each deposition cycle can include a precursor pulse period 212, a first plasma power period 214, and an optional second plasma power period 216. In the illustrated case, the deposition cycle 218 includes a cyclic deposition process. Prior to one or more deposition cycles 218, the above-mentioned temperature and / or pressure can be stabilized desirably.

[0058] During the precursor pulse period 212, the precursor is provided to the reaction chamber. In the example shown, the precursor is provided after the reactants are provided to the reaction chamber and before the power to form the plasma is provided. In addition, as shown, the precursor pulse period 212 stops before the first plasma power period 214 and the second plasma power period 216.

[0059] Exemplary precursors suitable for use with precursor pulse cycle 212 include one or more of silicon and metals. For example, the precursor may include a metal precursor, a silicon precursor, or both. Exemplary silicon precursors may be selected from aminosilanes, halosilanes, monosilanes, and disilanes as precursors. Aminosilanes and halosilanes include, but are not limited to, Si2Cl6, SiCl2H2, SiI2H2, bisdiethylaminosilane, bisdimethylaminosilane, hexaethylaminodisilane, tetraethylaminosilane, tert-butylaminosilane, bis-tert-butylaminosilane, trimethylsilyldiethylamine, trimethylsilyldiethylamine, and bisdimethylaminodimethylsilane. Exemplary metal precursors may include one or more of Ti, W, Ta, Mn, Hf, and / or Ru. For example, the precursor of titanium oxide may be at least one compound selected from titanium alkoxides and alkylaminotitaniums, including Ti(OR)4, where R is independently C x H y (x = 0, 1, 2, 3, 4 or 5, y = 2x + 1), and each R can be different (e.g. Ti (OCH3) 2 (OC2H5) (OC3H7)); Ti (NR2) 4, wherein R is independently C x Hy (x=0, 1, 2, 3, 4 or 5, y=2x+1), and each R can be different (e.g., Ti(N(CH3)(C2H5))4). Precursors of metal oxides other than titanium oxide can also be selected from any suitable compounds. In general, alkylamino precursors such as tetrakis-dimethylaminotitanium (TDMAT) can provide higher film growth rates than alkoxy precursors such as tetraisopropoxytitanium (TTIP) because precursors with smaller molecular sizes such as TDMAT tend to have less steric hindrance and thus have more adsorption sites than precursors with larger molecular sizes such as TTIP. The precursor flow rate with a carrier gas can be in the range of about 500 to about 5000 sccm. The duration of the precursor pulse period 212 can be from about 0.05 to about 5 seconds. During the reactant pulse period 204, the reactant is provided to the reaction chamber. In the example shown, the reactant is provided continuously during (e.g., before, during, and after) one or more deposition cycles 218.

[0060] Exemplary reactants suitable for use with reactant pulse period 204 include one or more of oxygen, hydrogen, and nitrogen, alone or in any combination with an inert gas. In some cases, the reactant may include a mixture of N2+H2, H2 or NH3, O2, N2O, CO2, etc. The reactant gas flow rate may be in the range of about 100 to about 10,000 sccm.

[0061] During the first plasma power cycle 214, power suitable for generating plasma is provided. The plasma may be a direct plasma formed in the reaction chamber. According to an example of the present disclosure, the power provided during the first plasma power cycle 214 has a relatively low frequency—for example, less than 1 MHz or between about 300 kHz and about 500 kHz. The power applied during the first plasma power cycle 214 may be less than 500 W (for example, for a 300 mm substrate) or a similar power density, or between about 50 W and about 500 W (for example, for a 300 mm substrate) or a similar power density. In the drawings and descriptions, LRF corresponds to low frequency power and HRF corresponds to high frequency power.

[0062] Although patterned structures can be formed using only higher frequency power (e.g., 13.56 MHz), higher power (e.g., 500 W) and longer plasma time are generally required to form layer 402. Patterned features may be damaged—e.g., due to the use of only higher power and / or longer duration of high frequency power to consume the patterned features. The damaged features may in turn lead to undesirable changes in subsequent etching processes.

[0063] During the second plasma power cycle 216, a second power suitable for generating plasma is optionally provided. The power frequency provided during the second plasma power cycle 216 is higher than the power frequency provided during the first plasma power cycle 214. For example, the frequency can be between about 13 MHz and about 14 MHz or between about 26 MHz and about 28 MHz. The power (W) applied during the cycle 216 can be the same or similar to the power provided during the cycle 214.

[0064] In some cases, the power supplied during the first plasma power cycle 214 and / or the second plasma power cycle 216 can be continuous or pulsed. The duration of one or more of the first plasma power cycle and the second plasma power cycle can be greater than 0 and less than 0.5 seconds, and / or the duration of each cycle can be greater than 0 to about 0.5 seconds per pulse.

[0065] like Figure 2 As shown, in some cases, the step of applying the first plasma power (first plasma power cycle) and the step of applying the second plasma power (second plasma power cycle) overlap. In some cases, the method may not include the step of applying the second plasma power.

[0066] The timing 200 may also include an inert gas pulse period 202, a carrier gas pulse period 206, a sealing gas pulse period 208, and a pressure pulse period 210. The inert gas pulse period 202 may include providing an inert gas (e.g., together with or overlapping with a reactant provided during the reactant pulse period 204). Exemplary inert gases include one or more of argon, helium, and / or nitrogen. The duration of the inert gas pulse period 202 may be the same or similar to the duration of the reactant pulse period 204. The flow rate of the inert gas may be between about 0 and about 10,000 sccm. As a specific example, the inert gas may be or include argon; during step 202, the flow rate of the inert gas may be greater than 3 slm or between greater than 3 slm and about 6 slm. As Fig.10 As shown in the figure, when the inert gas (such as Ar) flow rate is greater than 3slm, the membrane stress is lower than the existing conditions, while the membrane hardness is almost the same as the existing conditions. For example, when the process pressure is 425Pa, the Ar flow rate is 6slm, the HRF is 225W, and the LRF is 150W, the membrane hardness is 8.09GPa and the membrane stress is -235MPa.

[0067] During the carrier gas pulse period 206, a carrier gas (eg, to facilitate the provision of precursors), such as one or more of argon and helium, alone or in any combination, is provided to the reaction chamber. The flow rate of the carrier gas may be between about 500 and about 5000 sccm.

[0068] During the sealing gas pulse period 208, a sealing gas may be introduced into the interior of the reactor to facilitate separation of the reaction zone and the transfer zone within the reactor. As shown, the sealing gas pulse period 208 may start before a deposition cycle and end after the last deposition cycle.

[0069] Table 1 shows exemplary process conditions according to a specific example of the present disclosure. This table is intended to illustrate exemplary conditions and not necessarily to limit the scope of the present disclosure.

[0070] Table 1

[0071]

[0072]

[0073] Fig.12 Another sequence 1200 suitable for step 104 of forming a layer covering a substrate is shown. In this case, the sequence 1200 includes a deposition cycle 1202 and a treatment cycle 1204.

[0074] Deposition cycle 1202 may be the same or similar to the above-described deposition cycle 218. Specifically, deposition cycle 1202 may include a precursor pulse period 1206, a first plasma power period 1208 and / or a second plasma power period 1210, a reactant pulse period 1212, and an inert gas pulse or continuous supply 1214. Deposition cycle 1202 includes a cyclic deposition process. The above-mentioned temperature and / or pressure may be mentioned above in conjunction with steps 102 and 104, and may be stabilized before one or more deposition cycles 1202.

[0075] The precursor, reactant, inert gas, precursor pulse period 1206, reactant pulse period 1212, inert gas pulse period 1214, first and second plasma power pulse periods 1208 and 1210, first and second plasma power frequencies, and reactor conditions may be combined as described above. Figure 2 For example, the power applied during the first plasma power cycle 1208 can have a first frequency between about 300 kHz and about 500 kHz and / or a first plasma power between about 50 W and about 300 W or between about 100 W and about 200 W. Additionally or alternatively, the power applied during the second plasma power cycle 1210 can have a second frequency between about 13 MHz and about 14 MHz or between about 26 MHz and about 28 MHz and / or a second plasma power between about 100 W and about 400 W or between about 200 W and about 300 W. The first frequency can be a low radio frequency (LRF) and the second frequency can be a high radio frequency (HRF).

[0076] Prior to the step of treating the deposited material, the step of depositing the material may be repeated one or more times (cycle 1204). In addition, as shown, the deposition cycle 1202 and the treatment cycle 1204 may be repeated multiple times to obtain a desired film thickness and desired film / material properties. According to a specific example, the cycle of at least one step of depositing the material and at least one step of treating the deposited material is repeated multiple times.

[0077] The processing cycle 1204 or the step of processing the deposited material includes providing an oxygen-free gas to the reaction chamber (e.g., a continuation of the inert gas pulse 1214) and applying a third plasma power during a third plasma power period 1216 to form reactive species from the oxygen-free gas to process the deposited material, thereby forming a processed material.

[0078] The third plasma power can be between about 10 W and about 100 W or between about 30 W and about 80 W, and / or have a frequency between about 13 MHz and about 14 MHz or between about 26 MHz and about 28 MHz. In some cases, the frequency of the third plasma power during pulse period 1216 can be about the same as the power frequency (e.g., HRF frequency) during pulse period 1210. According to an example of the present disclosure, the frequency of the third plasma power is greater than the first frequency of the first plasma power.

[0079] One or more processing cycles may be used to further adjust the desired properties of the deposited / processed material. For example, the strength of the deposited material may be further increased and / or the stress of the deposited material may be reduced.

[0080] Table 2 shows exemplary process conditions according to a specific example of the present disclosure including process steps. This table is intended to illustrate exemplary conditions and not necessarily to limit the scope of the present disclosure.

[0081] Table 2

[0082]

[0083]

[0084] Fig.11 A film 1102 is shown deposited with an undesirably high stress overlying feature 1104 formation on substrate 1106. As film 1102 is etched to form patterned structures 1108-1114, patterned structures 1108-1114 may begin to tilt, which may detrimentally affect the desired pattern transfer.

[0085] Using methods as described herein, this undesirable tilting of the patterned structure can be reduced while maintaining the desired pattern by mitigating damage to the features 1104 during deposition of the film 1102 .

[0086] Treatment using an oxygen-free gas plasma may result in loss of material from feature 1104. However, using treatment steps as described herein, the elastic modulus of the treated material may be increased while reducing material loss from feature 1104 that may otherwise occur.

[0087] According to an example of the present disclosure, the ratio of the depositing material step to the processing deposited material step can be selected to adjust the desired strength (e.g., elastic modulus) and stress of the processed material. For example, the ratio of the number of depositing material steps to the number of processing deposited material steps can be between about 1:1 and about 30:1, or between about 3:1 and about 10:1, or between about 7:1 and about 10:1. According to further examples, the step of processing the deposited material (e.g., loop 1204) is repeated one or more times before proceeding to a subsequent step.

[0088] Back to Figure 1 Once step 104 (eg, sequence 200) is completed, a portion of layer 402 may be removed to form device structure 500, including patterned structures 502-508, also referred to as spacers, such as Figure 5 As shown. A portion of layer 402 may be removed using, for example, a dry etching process (eg, using active fluorine). Reactants during the dry etching process may include, for example, NF3 at about 50 to about 300°C.

[0089] During step 108, patterned features 308-312 or any remaining portions thereof may be removed. For example, an ashing process may be used to remove patterned features 308-312 to form device structure 600, such as Figure 6 shown.

[0090] During step 110, layer 306 may be etched using patterned structures 502-508 as a template mask to form device structure 700, such as Figure 7 Device structure 700 includes substrate 304 and patterned structures 702 - 708 formed thereon. Any suitable etching process may be used to form features 702 - 708 and will generally depend on the composition of layer 306 .

[0091] Now go to Figure 8 , shows a reactor system 800 according to an exemplary embodiment of the present disclosure. The reactor system 800 can be used to perform one or more steps or sub-steps described herein, and / or form one or more device structures or parts thereof described herein.

[0092] The reactor system 800 includes a pair of conductive plate electrodes 814, 818 parallel and facing each other in the interior 801 (reaction zone) of the reaction chamber 802. Although one reaction chamber 802 is shown, the system 800 may include two or more reaction chambers. Plasma can be ignited in the reaction chamber 802 by applying LRF or LRF+HRF power, for example, from a plasma power source 808 to one electrode (e.g., electrode 818) and electrically grounding the other electrode (e.g., electrode 814). A temperature regulator 803 may be disposed in the lower platform 814 (lower electrode), and the temperature of the substrate 822 placed thereon may be maintained at a desired temperature, such as the above-mentioned temperature. The electrode 818 may be used as a gas distribution device, such as a shower plate or showerhead. Precursor gas, reactant gas, carrier gas or inert gas (if any), etc. may be introduced into the reaction chamber 802 using one or more gas lines (e.g., reactant gas line 804 and precursor gas line 806, respectively connected to the reactant source and the precursor source). For example, inert gases and reactants (e.g., as described above) can be introduced into reaction chamber 802 using line 804, and / or precursors and carrier gases (e.g., as described above) can be introduced into reaction chamber using line 806. Although two inlet gas lines 804, 806 are shown, reactor system 800 can include any suitable number of gas lines.

[0093] In the reaction chamber 802, a circular duct 820 having an exhaust line 821 may be provided, through which the gas in the interior 801 of the reaction chamber 802 may be exhausted to the exhaust source 810. In addition, the transfer chamber 823 may be provided with a sealing gas line 829 to introduce the sealing gas into the interior 801 of the reaction chamber 802 via the interior (transfer zone) of the transfer chamber 823, wherein a partition plate 825 for separating the reaction zone 801 and the transfer chamber 823 may be provided (a gate valve is omitted in the figure, through which the substrate is transferred to or removed from the transfer chamber 823). The transfer chamber 823 may also be provided with an exhaust line 827 connected to the exhaust source 810. In some embodiments, the continuous flow of the carrier gas to the reaction chamber 802 may be achieved using a flow-through system (FPS).

[0094] Reactor system 800 may include one or more controllers 812, which are programmed or otherwise configured to implement one or more method steps described herein. Controller 812 is coupled to various power supplies, heating systems, pumps, robots, and gas flow controllers or valves of the reactor, as will be understood by those skilled in the art. For example, controller 812 can be configured to control the flow of precursors, reactants, and inert gases into at least one of the one or more reaction chambers to form a layer on the substrate surface. Controller 812 can be further configured to provide power (e.g., LRF or LRF+HRF) to form a plasma—e.g., in reaction chamber 802. Controller 812 can be similarly configured to perform additional steps as described herein. For example, controller 812 can be configured to control the flow of precursors and reactants into at least one of the one or more reaction chambers to form a layer covering the substrate, and provide a first plasma power and an optional second plasma power in at least one reaction chamber, wherein the first frequency of the first plasma power is different from the second frequency of the second plasma power. Controller 812 can be further configured to perform the steps of processing the deposited material as described above.

[0095] The controller 812 may include electronic circuits and software to selectively operate valves, manifolds, heaters, pumps, and other components included in the system 800. Such circuits and components are used to introduce precursors, reactants, and purge gases from respective sources. The controller 812 may control the timing of gas pulse sequences, the temperature of the substrate and / or reaction chamber, the pressure within the reaction chamber, and various other operations to provide proper operation of the system 800.

[0096] The controller 812 may include control software to electrically or pneumatically control valves to control the flow of precursors, reactants, and / or purge gases into and out of the reaction chamber 802. The controller 812 may include modules that perform certain tasks, such as software or hardware components, such as FPGAs or ASICs. The modules may advantageously be configured to reside on an addressable storage medium of the control system and configured to perform one or more processes.

[0097] In some embodiments, a dual chamber reactor (two portions or compartments for processing a substrate positioned close to each other) may be used, wherein reactant gases and inert gases may be supplied through shared lines, while precursor gases are supplied through non-shared lines.

[0098] During operation of system 800, a substrate such as a semiconductor wafer is transferred from, for example, substrate handling area 823 to reaction zone 801. Once the substrate is transferred to reaction zone 801, one or more gases, such as precursors, reactants, carrier gases, and / or purge gases, are introduced into reaction chamber 802.

[0099] Fig. 9Stress (MPa) and hardness (GPa) data for layers formed with only high frequency (HRF) power, only low frequency (LRF) power, HRF and LRF power, HRF power for only 1 second, and optionally with HRF and LRF at higher inert gas: reactant gas ratios (greater than 2) are shown. Hardness generally increases with increasing LRF power (e.g., from about 0 to 100 W to about 200 W). It is also shown that stress and dry etch rate generally decrease with increasing LRF power (e.g., from about 0 to 100 W to about 200 W). In fact, as LRF increases, stress becomes compressive. Film stress is generally related to the tilt of the patterned structure, so it is desirable to keep the film stress low. It is also shown that the elastic modulus is improved (increased) by increasing the LRF power during deposition of the layer.

[0100] The HRF and LRF powers, as well as the low frequency (LRF) power, can determine the mechanical properties of the film (e.g., desired hardness and stress). In addition, at these power settings, an inert gas: reactant gas ratio greater than 2 produces a film with desired properties, including a desired (relatively low) etch rate and / or a high etch rate ratio. The properties of the layer and / or patterned features (e.g., mechanical properties, such as those described herein) can be manipulated by one or more of: manipulating the inert gas: reactant flow ratio to the reaction chamber, manipulating the intensity of the first plasma power (e.g., LRF) and / or manipulating the duration of the first plasma power during the deposition cycle 1202 and / or the treatment 1204, and / or by manipulating the ratio of the deposition cycle to the treatment cycle as described above. For example, the inert gas: reactant flow ratio and / or the LRF power during the deposition cycle can be increased to reduce stress and / or reduce the etch rate and / or increase the hardness of the layer / structure. Therefore, exemplary methods such as method 100 can also include manipulating the properties of the patterned structure by, for example, one or more of: manipulating the inert gas: reactant flow ratio and / or manipulating the first plasma power.

[0101] Fig.13 Reduction of the Si-OH bond concentration of silicon oxide by treating the deposited material as described herein is shown. Fig.14 It is shown that the Si-ON bond concentration can also be reduced by treating the material as described herein. Fig.15 It is shown that the elastic modulus of the treated material increases with decreasing Si-OH bond concentration.

[0102] Fig.16 Similarly, it is shown that the elastic modulus of the processed material increases with the decrease of Si-ON bond concentration. Therefore, according to an example of the present disclosure, the strength of the processed material is greater than the strength of the deposited material. According to a further example, the elastic modulus of the processed material is greater than 60 GPa.

[0103] The concentration of Si-Si bonds in the silicon oxide deposited material generally increases as the concentration of Si-ON bonds and / or the concentration of Si-OH bonds decreases (e.g., as the concentration of impurities such as N and O decreases). Thus, according to examples of the present disclosure, the amount of Si-Si bonds in the processed material is greater than the amount of Si-Si bonds in the deposited material.

[0104] Fig.17 It is shown that the carbon concentration of silicon oxide formed according to the methods described herein is reduced by treating the deposited material as described herein. Thus, according to examples of the present disclosure, the amount of carbon impurities in the treated material is less than the amount of carbon in the deposited material.

[0105] Fig.18 It is shown that as the carbon concentration decreases, the stress in the processed material also decreases. Therefore, according to examples of the present disclosure, the stress of the processed material is less than the stress of the deposited material. For example, the stress of the processed material is -150 MPa or less (e.g., from 0 or neutral stress to -150 MPa) - such as when HRF is provided during the processing step.

[0106] like Figures 13 to 18 As shown, the treatment material can reduce the amount of impurities in the treated film, resulting in increased mechanical properties (eg, increased elastic modulus) and reduced stress (eg, relaxed film stress). Thus, tilting of the film can be minimized.

[0107] Fig.19 It is shown that damage to patterned features 1902 and 1904 is relatively low when forming layers 1906, 1908 - with or without processing steps as described above.

[0108] Fig.23 and 24 The elastic modulus values ​​and pattern feature size loss as a function of CK (ratio of deposition cycles to treatment cycles) are shown.

[0109] In the example shown, the plasma treatment time is Fig.23 is 0.8 seconds in Fig.24 is 4.0 seconds. As shown in the figure, Fig.24 Long plasma treatment times and Fig.23 The difference in material loss of patterned features between the short plasma treatment time in and the short plasma treatment time in is reduced. In other words, as the CK value increases, the damage to the sub-layer can be reduced. Other conditions can be as listed in Table 2. As shown in the figure, the material loss of patterned features can be reduced by increasing CK.

[0110] Fig. 20A and 20B Film stress and elastic modulus according to processing conditions are shown. Fig. 20A and Fig. 20BIt is shown that CK value, plasma power, and plasma treatment time can be used to manipulate stress and / or strength (elastic modulus) in the treated material.

[0111] like Fig. 20A and 20B As shown in the figure, when the CK value is greater than 3, the plasma power is low and the plasma treatment time is long, the film stress can be changed from compression to tension, and the strength (elastic modulus) can be increased. For example, when the CK value is greater than 3, the high-frequency plasma power is 50W, and the plasma treatment time is 4.5 seconds, the desired film stress can be obtained, that is, the film stress becomes tensile (that is, relaxed film stress), and the film strength increases.

[0112] Fig.21 It is shown that the stress and elastic modulus (example) of the film treated with the processing conditions according to the present disclosure can be improved compared with the conventional process. Fig. 20A and Fig. 20B When the plasma power is low and the treatment time is long, the film with stress and strength can have Fig.21 Membrane properties within the target membrane property region in .

[0113] Fig. 22 The effect of various power frequencies used during the processing steps is shown. Fig. 22 As shown in Figure 2, when the treatment is performed, the film strength (elastic modulus) is improved. In particular, when the treatment is performed with high frequency power, the film stress is greatly reduced compared to other conditions ( Fig.12 ) The application of high frequency RF power during the processing step is shown. Exemplary conditions are provided in Table 2 above.

[0114] The exemplary embodiments disclosed above do not limit the scope of the present invention, because these embodiments are merely examples of embodiments of the present invention. Any equivalent embodiments are within the scope of the present invention. In fact, in addition to the embodiments shown and described herein, various modifications of the present disclosure, such as the useful alternative combinations of the described elements, will become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.

Claims

1. A method for forming a patterned structure using a multiple patterning process, the method comprising the following steps: providing a substrate within a reaction chamber, the substrate comprising a surface including patterned features; and Forming a layer covering the substrate, wherein the step of forming the layer comprises: Depositing material, wherein the step of depositing material comprises: providing a precursor to the reaction chamber during a precursor pulse period; providing a reactant to the reaction chamber during a reactant pulse period; and applying at least one of a first plasma power having a first frequency less than 1 MHz during a first plasma power cycle and a second plasma power having a second frequency during a second plasma power cycle, wherein the first frequency is different from the second frequency; and Processing the deposited material, wherein the step of processing the deposited material comprises: providing an oxygen-free gas to the reaction chamber; and The third plasma power is applied in a third plasma power period to form active species from the oxygen-free gas to process the deposited material, thereby forming a processed material.

2. The method according to claim 1, wherein: The step of depositing the material is repeated one or more times before the step of processing the deposited material.

3. The method according to claim 1, wherein: The step of treating the deposited material is repeated one or more times before proceeding to a subsequent step.

4. The method according to claim 3, wherein: The ratio of the number of depositing material steps to the number of processing deposited material steps is between about 1:1 and about 30:1 or between about 3:1 and about 10:

1.

5. The method according to claim 4, wherein: The cycle of at least one step of depositing material and at least one step of treating the deposited material is repeated a plurality of times.

6. The method according to claim 1, wherein: The oxygen-free gas includes one or more of argon, helium and / or nitrogen.

7. The method according to claim 1, wherein: The patterned features include amorphous carbon.

8. The method according to claim 1, wherein: The amount of Si-Si bonds in the treated material is greater than the amount of Si-Si bonds in the deposited material.

9. The method according to claim 1, wherein: The amount of carbon in the processed material is less than the amount of carbon in the deposited material.

10. The method according to claim 1, wherein: The stress of the processed material is less than that of the deposited material.

11. The method according to claim 1, wherein: The strength of the processed material is greater than the strength of the deposited material.

12. The method according to claim 1, wherein: The frequency of the third plasma power is greater than the first frequency.

13. The method according to claim 1, wherein: The first plasma power is between about 50W and about 300W, or between about 100W and about 200W.

14. The method according to claim 1, wherein: The second plasma power is between about 100W and about 400W, or between about 200W and about 300W.

15. The method according to claim 1, wherein: The third plasma power is between about 10W and about 100W, or between about 30W and about 80W.

16. The method according to claim 1, wherein: During the step of depositing the material, the pressure within the reaction chamber is between about 100 Pa and about 500 Pa, or between about 200 Pa and about 400 Pa.

17. The method according to claim 1, wherein: During the step of depositing the material, the temperature of the substrate is between about 20°C and about 100°C, or between about 40°C and about 80°C.

18. The method according to claim 1, wherein: The first frequency is between about 300 kHz and about 500 kHz.

19. The method according to claim 1, wherein: The second frequency is between about 13 MHz and about 14 MHz, or between about 26 MHz and about 28 MHz.

20. The method according to claim 12, wherein: The frequency of the third plasma power is between about 13 MHz and about 14 MHz, or between about 26 MHz and about 28 MHz.

21. The method according to claim 1, wherein: The elastic modulus of the processed material is greater than 60 GPa.

22. The method according to claim 1, wherein: The stress of the processed material ranges from -150 MPa to about 0 Pa.

Images