Microwave enhanced atomic layer etch

Abstract

The present disclosure relates to a method of etching a material. The method includes a method of etching a material from a first surface of the material. In the method, a substrate having a first surface of material is provided into a reaction chamber and an etching step is performed. The etching step includes etching the first material by performing a plurality of etching cycles. Each etch cycle includes an etch reactant pulse that exposes the substrate to an etch reactant and an anneal pulse that exposes the substrate to an anneal. The disclosure also relates to a method of forming a semiconductor device and a semiconductor device. In addition, the present disclosure relates to a semiconductor processing system.

Description

Technical Field

[0001] The present invention relates generally to atomic layer etching (ALE) methods, and more particularly to ALE methods that use an annealing step such as microwave or infrared radiation to assist reactants in reacting with an etch target surface. Background Art

[0002] Atomic layer etching is cyclic, atomic layer level etching, using an etchant that adsorbs on the target film and reacts with the excited species. Compared with conventional etching techniques, ALE can perform precise, atomic layer level continuous etching on the sub-nanometer scale to form fine, narrow convex and concave patterns, and can be applied to, for example, double patterning processes. It is known that fluorine-based etchants such as HF can cause integration problems for certain applications. In addition, most known ALE examples have one or more steps of exposing the surface to plasma-generated substances. So-called plasma-enhanced ALE (or PE-ALE) is usually required to provide reactivity to produce surface reactions, which are required to produce volatile byproducts that allow film removal. Unfortunately, for many applications, the use of plasma is not ideal due to the non-uniformity of etching in high aspect ratio features, the high possibility of anisotropy, and the possibility of plasma damage.

[0003] The above and any other discussions of problems and solutions related to the related art have been included in this disclosure merely to provide a context for the present invention, and should not be considered as an admission that any or all of the discussions were known at the time the present invention was made. Summary of the invention

[0004] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the description of the example embodiments disclosed below. This summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0005] Various embodiments of the present disclosure relate to a method for etching a material from a first surface of the material. In the method, a substrate having a first surface of the material is provided to a reaction chamber and an etching step is performed. The etching step includes removing the first material by performing a plurality of etching cycles. Each etching cycle includes exposing the substrate to an etching reactant pulse of an etching reactant and exposing the substrate to an annealing pulse of an anneal.

[0006] In some embodiments, the method includes a substrate including a device side and a back side. A first material is located on the device side. In addition, the device side includes a second material. The etching step includes selectively etching the first material relative to the second material.

[0007] In some aspects, methods of forming semiconductor devices are disclosed that include etching processes according to the present disclosure.

[0008] In some aspects, semiconductor devices formed by methods including an etching process according to the present disclosure are disclosed.

[0009] In yet another aspect, a semiconductor processing system for processing a substrate is disclosed. The processing system includes: an etching space, which is constructed and arranged to hold a substrate having a first material; a container for an etching reactant, which is constructed and arranged to contain the etching reactant; and a generator for heating the substrate by polarization and oscillation of water molecules present on the substrate, the generator being disposed outside the etching space and being adapted to apply microwaves or infrared radiation to the etching space through a continuous wall of the etching space. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are included to provide a further understanding of the present disclosure and constitute a part of this specification, illustrate exemplary embodiments and together with the description help to explain the principles of the present disclosure. In the drawings:

[0011] Figure 1 is a schematic diagram of an exemplary embodiment of a method according to the present disclosure.

[0012] Figure 2 is a schematic diagram of an exemplary embodiment of a method according to the present disclosure.

[0013] Figure 3 (a) to (c) in FIG. 1 are block diagrams of exemplary embodiments of the method according to the present disclosure.

[0014] Figure 4 is a schematic diagram of an embodiment of a semiconductor processing system according to the present disclosure.

[0015] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. The illustrations presented herein are not meant to be actual views of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of the present disclosure. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0016] 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.

[0017] In the present disclosure, "gas" may include evaporated solids and / or liquids, and may consist of a single gas or a gas mixture. In the present disclosure, the process gas introduced into the reaction chamber for deposition through a shower head may include, consist of or consist essentially of an etchant gas and an additive gas. The additive gas typically includes a diluent gas for diluting the etchant gas and reacting with the etchant gas in an excited state. The etchant gas may be introduced together with a carrier gas such as a rare gas. In addition, gases other than the process gas, i.e., gases not introduced through a shower head, may be used, for example, to seal a reaction space, which includes a sealing gas such as a rare gas.

[0018] In some embodiments, the term "etchant reactant" generally refers to at least one compound that participates in the etching reaction of the target layer on the etching substrate, and in particular refers to at least one compound that is deposited on the target layer in an excited state and etches the target layer when activated by annealing. The term "etchant precursor" refers to at least one compound that contributes to the deposition of the etchant film, the activation of the etchant film, or catalyzes the etching reaction by the components of the etchant film. A diluent gas and / or a carrier gas can be used as an "etchant precursor". The term "carrier gas" refers to an inert or inactive gas in a non-excited state, which carries the etchant precursor in a mixed state to the reaction space and enters the reaction space as a mixed gas containing the etchant precursor. In the present disclosure, "etchant reactant", "etchant precursor" and "annealing pulse" can each independently act as a surface modifier or an etchant in some embodiments, with the limitation that each etching cycle has at least one of a surface modifier and an etchant.

[0019] In addition, in the present disclosure, any two numbers of a variable can constitute the workable range of the variable, because the workable range can be determined based on daily work, and any indicated range may or may not include endpoints. In addition, any value of the variable indicated (regardless of whether they are expressed by "about") may refer to an exact value or an approximate value, and include equivalents, and may refer to an average value, an intermediate value, a representative value, a majority value, etc. in some embodiments. In addition, the terms "consisting of" and "having" independently refer to "usually or broadly including", "comprising", "essentially consisting of" or "consisting of" in some embodiments. In addition, the article "one" or "an" refers to a species or genus including a plurality of substances. In the present disclosure, the meaning of any definition does not necessarily exclude the common and customary meanings in some embodiments.

[0020] In the present disclosure where conditions and / or structures are not specifically described, such conditions and / or structures can be easily provided by those skilled in the art as routine experiments in view of the present disclosure. In all disclosed embodiments, any element used in the embodiments can be replaced with any element equivalent thereto, including those elements explicitly, necessarily or inherently disclosed herein, for the intended purpose. In addition, the present invention can also be applied to devices and methods.

[0021] In some embodiments, "film" refers to a layer extending continuously in a direction perpendicular to the thickness direction, substantially without pinholes, to cover the entire target or relevant surface, or just a layer covering the target or relevant surface. In some embodiments, "layer" refers to a structure with a certain thickness formed on a surface, or a synonym for a film or non-film structure. A film or layer can 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 can be clear or unclear, and can 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.

[0022] As used herein, the term "substrate" may refer to any one or more underlying materials, including any one or more underlying materials that may be modified or on which a device, circuit, or film may be formed. A "substrate" may be continuous or non-continuous; rigid or flexible; solid or porous; and combinations thereof. A substrate may be in any form, such as a powder, a plate, or a workpiece. A plate-like substrate may include wafers of various shapes and sizes. A substrate may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0023] The continuous substrate may extend beyond the boundaries of the processing chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the processing chamber so that the process continues until the end of the substrate is reached. The continuous substrate may be provided from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0024] These embodiments will be explained with reference to the preferred embodiments. However, the present invention is not limited to the preferred embodiments.

[0025] Some embodiments provide a method for etching a material from a first surface of the material. In the method, a substrate having a first surface of the material is provided to a reaction chamber, and an etching step is performed. The etching step includes etching the first material by performing a plurality of etching cycles. Each etching cycle includes exposing the substrate to an etching reactant pulse of an etching reactant and exposing the substrate to an annealing pulse of annealing. In the present disclosure, the term "annealing" refers to electromagnetic radiation. Annealing is used to activate precursors, substrates, or surface sites during the etching cycle. In some embodiments, the electromagnetic radiation is microwave radiation. In this embodiment, in the etching cycle, the term annealing refers to microwave enhanced or microwave assisted etching. In some embodiments, the electromagnetic radiation is infrared radiation. In some embodiments, annealing does not include heat treatment. In some embodiments, annealing includes heat treatment. In this embodiment, in the etching cycle, the term annealing refers to infrared enhanced or infrared assisted etching. Microwave and infrared assisted and enhanced etching can all be defined as methods including exposing the substrate to radiation to activate the surface to achieve a chemical reaction, wherein the exposure occurs as described in a pulse sequence defined later in the present disclosure.

[0026] In one embodiment, during the anneal pulse, the reaction chamber is free of the etching reactants. The anneal pulse is performed after the substrate is exposed to the etching reactants, and optionally, after the etching reactants have been introduced into the reaction chamber, the chamber has been purged.

[0027] In one embodiment, during the etch reactant pulse, the substrate is exposed to an annealing pulse.

[0028] Some embodiments provide a method according to the aforementioned disclosure, wherein the substrate includes a device side and a back side. The first material is located on the device side. The device side also includes a second material. The etching step includes selectively etching the first material relative to the second material.

[0029] In some embodiments, the etch cycle further comprises an etch precursor pulse. The etch precursor pulse comprises exposing the substrate to the etch precursor.

[0030] In some embodiments, the substrate is first exposed to the etching reactant, and then the chamber is purged before the annealing pulse. Thereafter, the chamber is purged before the substrate is exposed to the etching precursor, and finally the chamber is purged a third time.

[0031] In some embodiments, the substrate is first exposed to the etching reactant, and then the chamber is purged before the substrate is exposed to the etching precursor. Thereafter, the chamber is purged before the annealing pulse, and finally the chamber is purged a third time.

[0032] In some embodiments, the substrate is first exposed to the etching reactant, and then the chamber is purged before the annealing pulse. Thereafter, the chamber is purged before the substrate is exposed to the etching precursor, and finally the chamber is purged a third time before the second annealing pulse.

[0033] In some embodiments, the substrate is exposed to the etching reactant and the annealing pulse simultaneously or at least partially overlapping.Thereafter, the chamber is purged before exposing the substrate to the etching precursor.

[0034] In some embodiments, the substrate is first exposed to the etching reactant. The reaction chamber is then purged before exposing the substrate to the etching precursor and the annealing pulses simultaneously or at least partially overlapping.

[0035] In some embodiments, the substrate is first exposed to the etching reactant and the annealing pulse simultaneously or at least partially overlapping.Then, the reaction chamber is purged before exposing the substrate to the etching precursor and the annealing pulse simultaneously or at least partially overlapping.

[0036] In some embodiments, the substrate is first exposed to the etching reactant and then the chamber is purged prior to the annealing pulse. The reaction chamber is then purged prior to exposing the substrate to the etching precursor and the annealing pulse simultaneously or at least partially overlapping.

[0037] In some embodiments, the substrate is first exposed to the etching reactant and the annealing pulse simultaneously or at least partially overlapping. Then, the reaction chamber is purged before exposing the substrate to the etching precursor. Finally, the reaction chamber is purged before the final annealing pulse.

[0038] In some embodiments, the annealing pulse occurs at least partially simultaneously with the etch precursor pulse and / or the etch reactant pulse. The effect of having the annealing pulse is that some precursors / etchants may need activation to react properly before encountering the substrate surface. Other precursors may react well at the surface without annealing, but require additional energy after the surface reaction to effectively produce the byproducts required for etching.

[0039] In some embodiments, the anneal pulse occurs at least partially simultaneously with the etch reactant pulse.

[0040] For a surface to be etched, the surface needs to be modified first and then exposed to the etchant. In the present disclosure, in one embodiment, the etching reactant acts as a surface modifier. In one embodiment, the etching reactant acts as an etchant. In one embodiment, the etching precursor acts as a surface modifier. In one embodiment, the etching precursor acts as an etchant. In one embodiment, the annealing pulse acts as a surface modifier. In one embodiment, the annealing pulse acts as an etchant.

[0041] As described above, annealing pulses, in other words, electromagnetic radiation can occur between reactant and / or precursor pulses, during reactant and / or precursor pulses, or to activate / deactivate the substrate surface. When radiation occurs between reactant and precursor pulses, the substrate is heated, which in some embodiments can cause the substrate to be heated to a temperature required for material etching during atomic layer etching. In some embodiments, heating causes the material on the substrate to be heated, which can cause the film to be heated to a temperature required for material etching during atomic layer etching. In one embodiment, the already deposited material can be annealed by exposure to radiation, which can cause changes in the properties of the material, which can create favorable conditions for further etching thereof. In one embodiment, the surface sites are rearranged due to the dipole activation of the radiation. Under certain conditions, the surface sites can be rearranged in a manner that promotes controllable atomic layer etching. Surface sites refer to ligands attached to the surface or top layer of the material to be etched.

[0042] In embodiments where radiation occurs during reactant and / or precursor pulses, the precursor may be activated in the gas phase in the reactor chamber. In other words, due to the radiation, the reactant or precursor may obtain additional reactivity in the gas phase. This may occur due to the dipole moment of the reactant or precursor. Additional reactivity may create conditions that promote atomic layer etching. In one embodiment, the reactant or precursor may be activated in the gas phase near the desired surface. The reactant or precursor may obtain additional reactivity near the surface due to the radiation and thus the heating of the material on the substrate. In one embodiment, the interaction of the reactant or precursor with the substrate and its higher reactivity is due to the dipole moment of the substrate and the reactant or precursor molecule or each of them. This may result in additional activation between the precursor molecule and the desired surface, thereby resulting in higher reactivity, which may promote controlled etching.

[0043] In an embodiment, when surface activation / deactivation leads to selective atomic layer etching, there are two possible ways in which radiation affects atomic layer etching. In one embodiment, the surface sites are rearranged by microwave radiation, which leads to surface deactivation. Under certain conditions, the surface sites can be rearranged in a way that suppresses controllable ALE. When one material can be deactivated, the other material can still remain activated, resulting in selective ALE. In one embodiment, etching is based on surface activation of one material, while the reactivity of the other material remains similar. This can result in different etching rates, resulting in controllable thicknesses of various materials.

[0044] In some embodiments, the substrate has a dipole moment. In some embodiments, the deposited material has a dipole moment. In some embodiments, the etching reactant has a dipole moment. Depending on the reactant selection, this will increase the reactant reactivity under microwave radiation. This is caused by the reactant symmetry, which affects the charge distribution within the molecule and thus its dipole moment. In symmetrical molecules, the dipole moments of the various bonds or functional groups balance each other, resulting in a low dipole moment, which results in a low dielectric constant.

[0045] In some embodiments, reactants can be selected based on their dielectric constant, depending on the desired outcome, which can be, for example: a) increased reactivity in the gas phase; b) increased reactivity near the surface due to friction between the precursor and the surface; or c) increased reactivity in the gas phase due to interaction with the surface.

[0046] In some embodiments, the reactant with a low dielectric constant can be selected from Ar, GeCl4, TiCl4, TEAl, AlBr4, BI3, allyl iodide, allyl bromide, allyl chloride and dichloromethane. In some embodiments, the reactant with a high dielectric constant can be selected from NH3 and SbBr3. In some embodiments, the reactant with an ultra-high dielectric constant can be selected from hydrazine, H2O and D2O.

[0047] In some embodiments, the etching cycle in the plurality of etching cycles also includes one or more purges. In this article, the term "purge" may refer to the act of removing any unwanted and unreacted products and by-products and any residual gases from the reaction chamber to stabilize the reaction space and prepare for the next step. In one embodiment, the chamber is purged between exposing the substrate to the etching reactant and the etching precursor. In one embodiment, the chamber is purged between exposing the substrate to the etching precursor and the annealing pulse. In one embodiment, the chamber is purged between exposing the substrate to the etching reactant and the etching precursor, and between exposing the substrate to the etching precursor and the annealing pulse. In one embodiment, the chamber is purged between exposing the substrate to the etching reactant and the etching precursor.

[0048] In some embodiments, the first material comprises a material selected from metal oxides, elemental metals, and metal nitrides. In some embodiments, the first material is a metal oxide selected from the group consisting of: MgO, MgAl x O y,CaO,SrTiO3,BaTiO3,Sc2O3,Y2O3,La2O3,Ce2O3,CeO2,Pr2O3,Nd2O3,SmO,Sm2O3,Gd2O3,Tb2O3,Dy 2O3,Ho2O3,Er2O3,Yb2O3,Lu2O3,TiO2,ZrO2,HfO2,ZrSiO4,HfSiO4,V2O3,VO2,V2O5,Nb2O5,Ta2O5,C In some embodiments, the first material is an elemental metal selected from the group consisting of Ti, Ta, Cr, Mo, W, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Al, Si, Ge, Sn, and Sb. In some embodiments, the first material is a metal nitride selected from the group consisting of: MgN, ScN, YN, LaN, TiN, ZrN, HfN, VN, VN x ,NbN,Nb3N5,NbN x ,TaN,Ta3N5,TaN x ,CrN x ,MoN,Mo2N,MoN x ,WN,W2N,WN x ,ReN x ,FeN x ,RuAl x N y ,RuSi x N y ,RuTa x N y ,RuTi x N y ,CoN x ,Ni3N,NiN x ,Cu3N,CuN x ,BN,AlN,GaN,InN,SiN,Si3N4,SiN x and SnN x .

[0049] In some embodiments, the etching precursor includes an oxidant or a chlorinating agent. In some embodiments, the oxidant is selected from ozone, oxygen, water, nitrous oxide and hydrogen peroxide. In some embodiments, the chlorinating agent is selected from phosphorus pentachloride, phosphorus trichloride, phosphorus oxychloride, thionyl chloride, sulfuryl chloride, disulfur dichloride, acetyl chloride, oxalyl chloride, N-chlorosuccinimide, hypochlorite.

[0050] In some embodiments, the chlorinating agent comprises a C-Cl bond. In some embodiments, the chlorinating agent is an acyl halide. In some embodiments, the chlorinating agent is oxalyl chloride. In some embodiments, the chlorinating agent is acetyl chloride.

[0051] In some embodiments, the chlorinating agent comprises an S-Cl bond. In some embodiments, the chlorinating agent is thionyl chloride. In some embodiments, the chlorinating agent is sulfonyl chloride. In some embodiments, the chlorinating agent is an alkylsulfonyl chloride. In some embodiments, the chlorinating agent is disulfur dichloride S2Cl2. In some embodiments, the chlorinating agent is sulfur dichloride SCl2.

[0052] In some embodiments, the chlorinating agent comprises a P-Cl bond. In some embodiments, the chlorinating agent is PCl3. In some embodiments, the chlorinating agent is PCl5. In some embodiments, the chlorinating agent is POCl3. In some embodiments, the chlorinating agent is a dialkylphosphine chloride (e.g., R2POCl, R=alkyl). In some embodiments, the chlorinating agent is a diarylphosphine chloride (e.g., R2POCl, R=aryl). In some embodiments, the chlorinating agent is an alkylphosphonic acid dichloride (e.g., RPOCl2, R=alkyl). In some embodiments, the chlorinating agent is an arylphosphonic acid dichloride (e.g., RPOCl2, R=aryl).

[0053] In some embodiments, the chlorinating agent comprises an N-Cl bond. In some embodiments, the chlorinating agent is N-chlorosuccinimide.

[0054] In some embodiments, the chlorinating agent comprises an O-Cl bond. In some embodiments, the chlorinating agent is an alkyl hypochlorite. In some embodiments, the chlorinating agent is tert-butyl hypochlorite.

[0055] In some embodiments, the etching reactants include reagents selected from the following: alkylating agents, cyclopentadiene, alkylcyclopentadiene, trimethylsilylcyclopentadiene, N,N'-dialkylcarbodiimide, dialkylamine, alcohol and halogenating agent. In some embodiments, the alkylating agent is selected from alkyl trifluoromethanesulfonate, such as ethyl trifluoromethanesulfonate, dialkyl carbonate, such as diethyl carbonate, dialkyl sulfate, such as dimethyl sulfate, trimethylsilyldiazomethane, alkyl halides, such as diiodomethane, tert-butyl iodide, ethyl iodide, 1-chlorohexane, 1-bromobutane, benzyl bromide and benzyl iodide, aryl halides, such as bromobenzene and iodobenzene, allyl halides 3-bromo-1-propylene, 3-iodo-1-propylene and 1-bromo-2-butene, and metal alkyl compounds, such as trimethylaluminum, triethylaluminum, diethylzinc and trimethylgallium. In some embodiments, the dialkylamine is selected from dimethylamine, diethylamine, ethylmethylamine, bis(trimethylsilyl)amine and diisopropylamine. In some embodiments, the alcohol is selected from methanol, ethanol, isopropanol, tert-butyl alcohol, tert-amyl alcohol, trimethylsilanol, and triethylsilanol.

[0056] In some embodiments, the halogenating agent is selected from the list of chlorinating agents listed above in the specification.

[0057] In some embodiments, the annealing pulse comprises a microwave pulse or an infrared pulse. The purpose of the annealing pulse is to assist the reaction of the reactant with the surface of the first material, or to assist the formation and / or removal of volatile byproducts, thereby driving the etching reaction and enabling the atomic layer etching process to operate under conditions that would otherwise be kinetically slow or thermodynamically unfavorable. The reactant may be an etchant such as a ligand, a conversion agent, or an etching precursor of the etching reactant.

[0058] In some embodiments, the annealing exposure is alternated with a self-limiting reaction of a single reactant. In some embodiments, the annealing exposure is alternated with a self-limiting reaction of two or more reactants applied sequentially. In some embodiments, the annealing exposure is performed simultaneously with the introduction of a reactant during the sequential application of one or more other reactants, wherein each reactant provides a self-limiting reaction during the atomic layer etching process. In some embodiments, the annealing exposure is performed simultaneously with the separate introduction of multiple reactants, each reactant being applied sequentially to provide a self-limiting reaction during the atomic layer etching process.

[0059] In some embodiments, microwaves are applied at a frequency of 0.3-300 GHz, for example 0.5-100 GHz, such as 1-20 GHz or 2-5 GHz.

[0060] In some embodiments, infrared light is applied at a wavelength of 0.7-1000 μm, for example 1-800 μm, such as 20-600 μm or 30-500 μm.

[0061] In some embodiments, the etching cycle is repeated, for example at least once, for example at least twice, for example at least ten times, for example at least twenty times, for example at least fifty times, for example at least one hundred times, for example at least five hundred times, for example at least one thousand times, for example at least five thousand times.

[0062] In some embodiments, the etching cycle is repeated until the first material is removed from the substrate. In some embodiments, the etching cycle is repeated until a predetermined thickness of the first material is removed from the substrate. The predetermined value may be, for example, 0.1 to 20 nm, for example, 0.5 to 15 nm, for example, 1.5 to 10 nm, for example, 2 to 7 nm, for example, about 0.5 nm, for example, about 1 nm, for example, about 2 nm.

[0063] In some embodiments, the second material includes a polymer.

[0064] In some embodiments, the polymer has a dielectric constant of 4.1 or less. The difference in dielectric constants between the second material and the first material allows the second material to not be heated during the annealing step and, therefore, not be etched away from the substrate. In some embodiments, the polymer is selected from polytetrafluoroethylene, polyvinylidene fluoride, poly(isobutylene ethylene), polyvinyl fluoride, poly(ethylene), poly(isobutylene), poly(propylene), poly(1-butene), poly(1,4-butadiene), poly(2-methylstyrene), poly(4-methylstyrene), polystyrene, poly(propylene glycol), polytetrahydrofuran, poly(chlorotrifluoroethylene), poly(cyclohexyl methacrylate), poly(1,4-phenylene ether), poly(4-chlorostyrene), poly(isobutyl methacrylate), poly(butyl methacrylate), poly (2-chlorostyrene), poly(2,6-diphenyl-p-phenylene oxide), poly(ethyl methacrylate), polyvinylidene chloride, poly(caprolactone), polyacetal, poly(methylene oxide), poly(bisphenol A carbonate), poly(2-chloro-p-xylene), poly(methyl methacrylate), poly(thio-1,4-phenylene), polyvinyl chloride, poly(acrylonitrile), poly(butylene terephthalate), poly(vinyl acetate), poly(ethylene terephthalate), polyadipamide, polyadipimide, polyamide, and polycaprolactam.

[0065] Some embodiments provide a method of forming a semiconductor device comprising an etching process according to any one of the preceding claims.

[0066] Some embodiments provide semiconductor devices formed by methods including an etching process according to the present disclosure.

[0067] Some embodiments provide a semiconductor processing system for processing a substrate. The processing system includes: an etching space, which is constructed and arranged to accommodate a substrate having a first material; a container for an etching reactant, which is constructed and arranged to accommodate the etching reactant; and a generator, which heats the substrate by polarization and oscillation of water molecules present on the substrate. The generator is disposed outside the etching space and is suitable for applying microwaves or infrared radiation to the etching space through a continuous wall of the etching space.

[0068] In some embodiments, the generator can be located on any side of the etching space. In one embodiment, the generator is located at the top of the etching space. In one embodiment, the generator is located on the side of the etching space. In one embodiment, the generator surrounds the etching space. In one embodiment, the generator can be moved and locked in any position around the etching space to adjust the direction of the microwave or infrared radiation toward the substrate. In this way, the generator directs the radiation to the surface of the substrate.

[0069] In some embodiments, the generator is located in a separate chamber so that the substrate is first exposed to the etching reactants in the etching space. The substrate is then moved to a second chamber to be exposed to microwave or infrared radiation.

[0070] In some embodiments, the substrate additionally includes a second material.

[0071] In some embodiments, the semiconductor processing system further includes a container for an etch precursor constructed and arranged to contain the etch precursor.

[0072] In some embodiments, the second material is not removed from the substrate surface.

[0073] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0074] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0075] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown can be performed in the order shown, in other orders, or omitted in some cases.

[0076] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

[0077] In some embodiments, Figure 1 The process is performed as shown, Figure 1 A flowchart of atomic layer etching (ALE) is shown. In step 111, a film of a first material is deposited on a substrate surface by any suitable deposition method, such as plasma enhanced atomic layer deposition, plasma enhanced chemical vapor deposition, thermal atomic layer deposition or thermal chemical vapor deposition, which methods can preferably perform conformal deposition. Step 112 is an optional purge step for purging the reaction space. In other words, the purge step flushes the reaction space out of any previously supplied gas or reactant. After step 112, in step 113, the deposited film is exposed to an etching reactant. During this step, the etching reactant reacts with the surface of the deposited film. In step 114, the substrate is optionally exposed to an etching precursor. In step 115, an annealing pulse is applied to the reaction space. During this step, a microwave pulse or infrared radiation is applied to the substrate. Steps 113, 114 and 115 together form an etching cycle. Steps 113, 114 and 115 can be performed in any order. In some embodiments, the annealing pulse 115 can be after steps 113 and 114. The etching cycle removes at least a portion of the first material. The etching cycle is repeated as many times as desired 117. In some embodiments, the etching cycle is repeated, for example, 10 times, for example, 20 times, for example, 50 times, or for example, 100 times. After the first material is completely etched or etched to a desired thickness, the process ends 116.

[0078] In some embodiments, Figure 2 The process is performed as shown, Figure 2A flow chart of selective atomic layer etching is shown. In step 211, a film of a first material is deposited on a substrate surface by any suitable deposition method that can preferably perform conformal deposition. In step 212, a film of a second material is deposited on the substrate. The second material is preferably a polymer with a low dielectric constant. Step 213 is an optional purge step for purging the reaction space. In other words, the purge step flushes the reaction space out of any previously supplied gas or reactant. After step 213, in step 214, the deposited film is exposed to an etching reactant. During this step, the etching reactant reacts with the surface of the deposited film. In step 215, the substrate is optionally exposed to an etching precursor. In step 216, an annealing pulse is applied to the reaction space. During this step, a microwave pulse or infrared radiation is applied to the substrate. Steps 214, 215, and 216 together form an etching cycle. The etching cycle removes at least a portion of the first material without removing a large amount of the second material. Repeat the etching cycle 218 as many times as needed. In some embodiments, the etching cycle is repeated, for example, 10 times, for example, 20 times, for example, 50 times, or for example, 100 times. After the first material is completely etched or etched to a desired thickness, the process ends 217 .

[0079] Figure 3 A schematic diagram of one cycle of an etching process according to an embodiment of the present invention is shown, wherein (a) represents a deposition step, (b) represents a pre-etching step, and (c) represents an etching step.

[0080] Figure 3 A schematic diagram of a cycle of an etching process according to an embodiment of the present invention is shown, wherein (a) represents a deposition step, (b) represents a pre-etching step, and (c) represents an etching step. Prior to the deposition step (step (a)), a substrate 41 (e.g., a silicon wafer or other semiconductor wafer) on which a first material 42 is formed is provided in a reaction space. In the deposition step, an etchant film 43 is deposited on a target layer 42 with a thickness not less than a saturation thickness T1, wherein the etchant film 43 and the first material layer 42 are in contact with each other. The saturation thickness T1 is defined as such a thickness that the portion of the etchant film exceeding the thickness does not contribute to the etching of the first material layer, i.e., even if the thickness of the etchant film further increases beyond the saturation thickness T1, the etching amount of the first material layer will not increase. In the pre-etching step (step (b)), the etchant film 43 is exposed to annealing, such as microwave or infrared radiation, thereby etching the etchant film, generating a gas component therefrom, and removing the top of the etchant film 43 above the saturation thickness T1.

[0081] When etching of the etchant film 43 proceeds and the etchant film 43 is etched to the saturated thickness T1 , a gas component from the etchant film 43 simultaneously generates a gas component from a portion of the first material layer 42 having the depth T2 .

[0082] The boundary region 44 includes a boundary region of the etchant film 43 having a saturated thickness T1 and a boundary region of the first material layer 42 having a depth T2. The total thickness (T1+T2) of the boundary region may depend on the energy in the annealing and the pressure of the reaction space. The boundary region 44 may include an intermediate composed of mixed components.

[0083] In the etching step (step (c)), the boundary region or the intermediate layer 44 is removed as a gas component, wherein the target layer 42 is etched by a depth T2 to obtain an etched first material layer 45. It should be noted that although steps (b) and (c) are shown separately for easy understanding of the principles of these steps, these steps occur simultaneously.

[0084] Figure 4 An exemplary embodiment of a semiconductor processing system 200 according to the present disclosure is shown. As a schematic representation of the semiconductor processing system 20, many components have been omitted for simplicity of illustration, and these components may include, for example, various inlets, outlets, valves, manifolds, purifiers, heaters, containers, vents, and / or bypasses.

[0085] The semiconductor processing system 20 includes an etching space 21 , an etching reactant container 22 for containing an etching reactant, an inlet 23 for providing the etching reactant into the etching space 21 , and an outlet 24 for removing the etching reactant from the etching space 21 .

[0086] The etching space 21 may be a reaction chamber. The etching space 21 may be configured and arranged to hold one substrate. Alternatively, the etching space 21 may be configured and arranged to hold two or more substrates.

[0087] According to the present invention, the reactant reservoir 22 is configured and arranged to hold etching reactants. In some embodiments, the semiconductor processing system 20 includes a second or additional reactant or precursor reservoir (not shown). For example, additional oxidants or other auxiliary agents can be stored in the second reactant reservoir, and the auxiliary agents can be mixed with the etching reactants as needed.

[0088] The spent etching reactants can be removed from the etching space 21 through the outlet 24. The spent etching liquid can be collected in a disposal reservoir 25.

[0089] Figure 4 The embodiment of the semiconductor processing system further comprises a generator 27 for heating the substrate by polarization and oscillation of water molecules present on the substrate. The generator 27 is located outside the etching space 21 and is suitable for applying microwaves or infrared radiation to the etching space through the continuous wall of the etching space 21.

[0090] Figure 4Embodiments of the semiconductor processing system of the present invention further include a controller 26. The controller 26 includes electronic circuits and software to selectively operate valves, manifolds, heaters, pumps, and other components included in the semiconductor processing system 20. Such circuits and components are used to provide fluids, adjust temperature, pressure, etc. to provide proper operation of the semiconductor processing system 20. The controller 26 may include modules, such as software or hardware components, that perform specific tasks. The modules may be configured to reside on an addressable storage medium of the control system and configured to perform one or more processes.

[0091] During operation of semiconductor processing system 20, one or more substrates, such as semiconductor wafers (not shown), are transferred to etching space 21. Depending on the configuration of system 20, etching liquid is provided into etching space 21, or the substrates are contacted with etching liquid previously present in etching space 21.

Claims

1. A method for etching, comprising: - providing a substrate comprising a first material to a reaction chamber; - performing an etching step, the etching step comprising etching the first material by performing a plurality of etching cycles, wherein an etching cycle in the plurality of etching cycles comprises an etching reactant pulse and an annealing pulse; wherein the etch reactant pulse comprises exposing the substrate to the etch reactant; and The annealing pulse includes exposing the substrate to an anneal.

2. The method according to claim 1, -in, The substrate comprises a device side and a back side; - wherein the first material is located on the device side; - wherein the device side further comprises a second material; and - wherein the etching step comprises etching the first material selectively relative to the second material. 3 . The method of claim 1 , the etch cycle further comprising an etch precursor pulse, wherein the etch precursor pulse comprises exposing the substrate to the etch precursor.

4. The method according to claim 1 or 2, wherein: The anneal pulse occurs at least partially simultaneously with the etch precursor pulse.

5. The method according to any one of claims 1 to 4, wherein: The anneal pulse occurs at least partially simultaneously with the etch reactant pulse.

6. The method according to any one of claims 1 to 3, wherein: An etching cycle in the plurality of etching cycles further includes one or more purges.

7. A method according to any one of the preceding claims, wherein: The first material includes a metal oxide, an elemental metal, or a metal nitride.

8. The method according to any one of claims 3 to 7, wherein: The etching precursor includes an oxidizing agent or a chlorinating agent.

9. A method according to any one of the preceding claims, wherein: The etching reactants include a reagent selected from the group consisting of an alkylating agent, cyclopentadiene, alkylcyclopentadiene, trimethylsilylcyclopentadiene, N,N'-dialkylcarbodiimide, dialkylamine, alcohol, and a halogenating agent.

10. A method according to any one of the preceding claims, wherein: The annealing pulse includes a microwave pulse or an infrared pulse.

11. The method according to claim 10, wherein: Microwaves are applied at a frequency of 0.3-300 GHz.

12. The method according to claim 10, wherein: Infrared light is applied at a wavelength of 1-800 μm.

13. A method according to any one of the preceding claims, wherein: The etching cycle is repeated at least twice.

14. The method according to any one of claims 1 to 12, wherein: The etching cycle is repeated until the first material is removed from the substrate.

15. The method according to claim 2, wherein: The second material includes a polymer.

16. The method according to claim 15, wherein: The polymer has a dielectric constant of 4.1 or less.

17. A method of forming a semiconductor device comprising an etching process according to any one of the preceding claims.

18. A semiconductor device formed by a method comprising an etching process according to any one of claims 1 to 16.

19. A semiconductor processing system for processing a substrate, the processing system comprising: an etching space constructed and arranged to hold a substrate having a first material; a container for an etching reactant constructed and arranged to contain the etching reactant; as well as A generator for heating the substrate by polarization and oscillation of water molecules present on the substrate is arranged outside the etching space and is suitable for applying microwaves or infrared radiation to the etching space through a continuous wall of the etching space.

20. The semiconductor processing system of claim 19, wherein: The substrate also includes a second material.

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