Microwave enhancement atomic layer etching

Abstract

To provide a method for etching a material, a method for forming a semiconductor device, a semiconductor device, and a semiconductor processing system.SOLUTION: The method includes etching a material from a first surface of a material. The method includes the step of providing a base material with a first surface of the material in a reaction chamber and etching the base material. The etching step includes executing a plurality of etching cycles to etch the first material. Each etching cycle includes an etching reactant pulse for exposing the base material to an etching reactant and an anneal pulse of exposing the base material to an anneal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates generally to methods of atomic layer etching (ALE), and in particular to ALE methods that use an annealing step, such as microwave or infrared, to assist reaction of reactants with a surface targeted for etching. [Background technology]

[0002] Atomic layer etching is a cyclic atomic layer-level etch using an etchant that is adsorbed on a target film and reacts with excited species. Compared to conventional etching techniques, ALE can perform precise atomic layer-level sequential etching on the order of sub-nanometers to form fine and narrow relief patterns, which may be suitable for, for example, double patterning processes. Fluorine-based etchants such as HF are known to cause integrity problems for some applications. Most of the known implementations of ALE also have one or more steps that use exposure of the surface to plasma-generated species. So-called plasma-enhanced ALE (or PE-ALE) is often required to provide the reactivity required to generate the surface reactions that generate volatile by-products that enable film removal. Unfortunately, in many applications, the use of plasma is undesirable due to the non-uniformity of etching in high aspect ratio features, the possibility of high anisotropy, and the possibility of plasma damage.

[0003] The above and any other discussions of problems and solutions relating to the related art are included in this disclosure merely for the purpose of providing a context for the invention, and should not be construed as an understanding that any or all of the discussion was known at the time the invention was made. Summary of the Invention

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are described in more detail below in the description of exemplary embodiments of the disclosure. This Summary is not intended to identify 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 of etching a material from a first surface of the material, in which a substrate having a first surface of the material is provided in a reaction chamber and an etching process is performed, the etching process including removing the first material by performing a plurality of etching cycles, each etching cycle including an etching reactant pulse that exposes the substrate to an etching reactant and an annealing pulse that exposes the substrate to an anneal.

[0006] In some embodiments, the method includes a substrate having a device side and a backside. A first material is positioned on the device side. Additionally, 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, a method of forming a semiconductor device is disclosed that includes an etching process according to the present disclosure.

[0008] In some aspects, a semiconductor device is disclosed that is formed by a method that includes an etching process according to the present disclosure.

[0009] In yet another aspect, a semiconductor processing system for processing a substrate is disclosed, the processing system comprising an etching space constructed and arranged to hold a substrate having a first material, an etching reactant container constructed and arranged to contain an etching reactant, and a generator for heating a substrate by polarization and vibration of water molecules present on the substrate, the generator being arranged outside the etching space and adapted to apply microwave or infrared radiation to the etching space through a continuous wall of the etching space.

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

[0011] [Figure 1] FIG. 1 is a schematic representation of an exemplary embodiment of a method according to the present disclosure. [Diagram 2] FIG. 2 is a schematic representation of an exemplary embodiment of a method according to the present disclosure. [Diagram 3] FIG. 3 is a block diagram of an exemplary embodiment of a method according to the present disclosure. [Figure 4] FIG. 4 is a schematic diagram of an embodiment of a semiconductor processing system according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] It is understood that elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. The illustrations presented herein are not meant to be actual representations of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of the present disclosure. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the illustrated embodiments of the present disclosure.

[0013] Although certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious modifications and equivalents thereof, and therefore it is not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0014] In this disclosure, "gas" can include vaporized solids and / or liquids and can be composed of a single gas or a mixture of gases. In this disclosure, the process gas introduced into the reaction chamber through the showerhead may be composed of, consist essentially of, or consist of an etchant gas and an additive gas. The additive gas typically includes a dilution gas to dilute the etchant gas and react with the etchant gas when in an excited state. The etchant gas can be introduced with a carrier gas, e.g., a noble gas. Also, gases other than the process gas, i.e., gases introduced without passing through the showerhead, may be used to seal the reaction space, including, for example, a seal gas, e.g., a noble gas.

[0015] In some embodiments, the term "etchant reactant" generally refers to at least one compound that participates in an etching reaction that etches a target layer on a substrate, particularly at least one compound that deposits 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 an etchant film, the activation of an etchant film, or catalyzes an etching reaction by a component of the etchant film. A dilution gas and / or a carrier gas can function as an "etchant precursor". The term "carrier gas" refers to a non-excited, inert, or inactive gas that, in a mixed state, carries the etchant precursor to the reaction space and enters the reaction space as a mixed gas containing the etchant precursor. In the present disclosure, in some embodiments, the "etchant reactant", "etchant precursor", and "anneal pulse" can each independently act as a surface modifier or an etchant, with the limitation that each etching cycle has at least one of a surface modifier and an etchant.

[0016] Further, in this disclosure, any two variables may constitute a workable range for that variable, since a workable range can be determined based on routine work, and any range stated may include or exclude the endpoints. In addition, in some embodiments, any value of a stated variable (whether or not they are stated with "about" attached) may refer to an exact value or an approximate value, including its equivalent, and may also refer to an average, median, representative value, major value, and the like. In addition, the terms "comprised of" and "having" refer independently in some embodiments to "typically or broadly including," "comprise," "consist essentially of," or "consist of." Similarly, the article "a" or "an" refers to a species, species, or genus, including a plurality of species. In this disclosure, any defined meaning does not necessarily exclude, in some embodiments, the ordinary and customary meaning.

[0017] In the present disclosure where conditions and / or structures are not specified, those skilled in the art can easily provide such conditions and / or structures in view of the present disclosure as a matter of routine experimentation. In all of the disclosed embodiments, any element used in the embodiment can be replaced with any element equivalent thereto for the intended purpose, including those explicitly, necessarily, or inherently disclosed herein. Furthermore, the present invention can be equally applied to apparatus and methods.

[0018] In some embodiments, a "film" refers to a layer that extends continuously in a direction perpendicular to the thickness direction, substantially without pinholes, to cover the entire object or relevant surface, or simply a layer that covers the object or relevant surface. In some embodiments, a "layer" refers to a structure having a certain thickness formed on a surface, or a synonym of a film, or a non-film structure. A film or layer may be composed of a separate single film or layer, or multiple films or layers, having specific properties, and the boundaries between adjacent films or layers may be distinct or indistinct, and may be defined based on any physical, chemical, and / or other characteristics, formation process or sequence, and / or function or purpose of adjacent films or layers.

[0019] As used herein, the term "substrate" may refer to any underlying material or materials, including any underlying material or materials, that may be modified or upon 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. The substrate may be in any form, such as a powder, a plate, or a workpiece. Substrates in the form of plates may include wafers of various shapes and sizes. Substrates may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0020] The continuous substrate may extend beyond the boundaries of the process chamber in which the deposition process occurs. In some processes, the continuous substrate may move through the process chamber, such that the process continues until the end of the substrate is reached. The continuous substrate may be fed from a continuous substrate feeding system to enable the production and output of a continuous substrate in any suitable form.

[0021] The embodiments are described in terms of preferred embodiments, however, the invention is not limited to the preferred embodiments.

[0022] Some embodiments provide a method of etching a material from a first surface of the material. In the method, a substrate having a first surface of the material is provided in a reaction chamber and an etching process is performed. The etching process includes etching the first material by performing a plurality of etching cycles. Each etching cycle includes an etching reactant pulse that exposes the substrate to an etching reactant and an annealing pulse that exposes the substrate to an annealing. In this disclosure, the term "annealing" refers to electromagnetic radiation. Annealing is used to activate either the precursor, the substrate, or the surface site during the etching cycle. In some embodiments, the electromagnetic radiation is microwave radiation. In this embodiment, the term annealing in the etching cycle refers to microwave-enhanced or microwave-assisted etching. In some embodiments, the electromagnetic radiation is infrared radiation. In some embodiments, the annealing does not include a thermal treatment. In some embodiments, the annealing includes a thermal treatment. In this embodiment, the term annealing in the etching cycle refers to infrared-enhanced or infrared-assisted etching. Both microwave and infrared assisted and enhanced etching can be defined as methods that involve radiation exposure to a substrate to activate the surface and enable chemical reactions, the exposure occurring as described in the pulse sequences defined later in this disclosure.

[0023] In one embodiment, no etch reactants are present in the reaction chamber during the anneal pulse, which is performed after the substrate is exposed to the etch reactants and, optionally, after the etch reactants are delivered into the reaction chamber, purging the chamber.

[0024] In one embodiment, the substrate is exposed to an annealing pulse during the etching reactant pulse.

[0025] Some embodiments provide a method according to the preceding disclosure, wherein the substrate comprises a device side and a backside. The first material is located on the device side. The device side further comprises a second material. The etching step comprises selectively etching the first material relative to the second material.

[0026] In some embodiments, the etching cycle further comprises an etch precursor pulse. The etch precursor pulse comprises exposing the substrate to an etch precursor.

[0027] In some embodiments, the substrate is first exposed to the etching reactants and then the chamber is purged prior to the annealing pulse, the chamber is then purged prior to exposing the substrate to the etching precursor, and finally the chamber is purged a third time.

[0028] In some embodiments, the substrate is first exposed to the etching reactants and then the chamber is purged before exposing the substrate to the etching precursor, the chamber is then purged before the anneal pulse, and finally the chamber is purged a third time.

[0029] In some embodiments, the substrate is first exposed to an etching reactant and then the chamber is purged prior to an annealing pulse, then the chamber is purged prior to exposing the substrate to an etching precursor, and finally the chamber is purged a third time prior to a second annealing pulse.

[0030] In some embodiments, the substrate is exposed to the etching reactants and the annealing pulse simultaneously or at least partially overlapping, after which the chamber is purged before exposing the substrate to the etching precursor.

[0031] In some embodiments, the substrate is not exposed to plasma reactants during the etching cycle, and the reaction chamber is then purged before exposing the substrate to the etching precursor and annealing pulses simultaneously or at least partially overlapping.

[0032] In some embodiments, the substrate is first exposed to the etch reactant and anneal pulses simultaneously or at least partially overlapping, and the reaction chamber is then purged before exposing the substrate to the etch precursor and anneal pulses simultaneously or at least partially overlapping.

[0033] In some embodiments, the substrate is first exposed to the etching reactants 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.

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

[0035] In some embodiments, the anneal pulse occurs at least partially simultaneously with the etch precursor pulse and / or the etch reactant pulse. The effect of having an anneal pulse is that some precursors / etchants may require activation before encountering the substrate surface in order to react properly. Other precursors may react well at the surface without annealing, but require excess energy after the surface reaction to effectively generate the by-products required for etching.

[0036] In some embodiments, the anneal pulse occurs at least partially simultaneously with the etch reactant pulse.

[0037] For a surface to be etched, the surface must first be modified and then exposed to an etchant. In the present disclosure, in one embodiment, the etch reactant acts as a surface modifier. In one embodiment, the etch reactant acts as an etchant. In one embodiment, the etch precursor acts as a surface modifier. In one embodiment, the etch precursor acts as an etchant. In one embodiment, the anneal pulse acts as a surface modifier. In one embodiment, the anneal pulse acts as an etchant.

[0038] As mentioned above, an annealing pulse, in other words electromagnetic radiation, can be generated between reactant and precursor pulses, during reactant and / or precursor pulses, or to activate / deactivate the substrate surface. The generation of radiation between reactant and precursor pulses heats the substrate, which in some embodiments can lead to heating the substrate to a temperature desired for material etching in an atomic layer etching process. In some embodiments, the heating leads to heating of the material on the substrate, which can lead to heating of the film to a temperature desired for material etching in an atomic layer etching process. In one embodiment, an already deposited material can be annealed by exposure to radiation, which can result in a change in the material suitable to create favorable conditions for its further etching. In one embodiment, surface sites are rearranged due to dipole activation by radiation. Under certain conditions, surface sites can be rearranged in a manner that promotes controllable atomic layer etching. By surface sites is meant ligands that are attached to the surface, or top layer, of the material to be etched.

[0039] In embodiments where radiation occurs during the reactant and / or precursor pulse, the precursor can be activated in the gas phase in the reaction chamber. In other words, the reactant or precursor can obtain additional reactivity in the gas phase by the radiation. This can occur due to the dipole moment of the reactant or precursor. The additional reactivity can create conditions that promote atomic layer etching. In one embodiment, the reactant or precursor can be activated in the gas phase near the desired surface. The reactant or precursor can obtain additional reactivity near the surface due to the radiation and therefore 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 both the substrate and the reactant or precursor molecule, or one of each. This can cause additional activation between the precursor molecule and the desired surface, causing higher reactivity and promoting controllable etching.

[0040] In an embodiment, surface activation / passivation leads to selective atomic layer etching, and there are two possible ways that radiation can affect atomic layer etching. In one embodiment, surface sites are rearranged by microwave irradiation, which leads to surface passivation. Under certain conditions, surface sites can be rearranged in a way that inhibits controllable ALE. One material can be passivated while another material still remains activated, resulting in selective ALE. In one embodiment, etching is based on surface activation of one material while its reactivity towards another material remains similar. This can lead to different etch rates, leading to controllable thicknesses for various materials.

[0041] 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. This increases the reactant reactivity under microwave radiation depending on the choice of reactant. This is caused by reactant symmetry, which affects the distribution of charge within the molecule and, consequently, its dipole moment. In symmetric molecules, the dipole moments of the individual bonds, or functional groups, balance each other, resulting in a low dipole moment and therefore a low dielectric constant.

[0042] In some embodiments, the choice of reactants can be based, for example, on the dielectric constant of the reactants depending on the desired outcome, which can, for example, a) increase reactivity in the gas phase, b) increase reactivity near the surface due to rubbing of the precursor with the surface, or c) increase reactivity in the gas phase due to interaction with the surface.

[0043] In some embodiments, the reactant having a low dielectric constant may be selected from the group consisting of Ar, GeCl4, TiCl4, TEAl, AlBr4, BI3, allyl iodide, allyl bromide, allyl chloride, and methylene chloride. In some embodiments, the reactant having a high dielectric constant may be selected from the group consisting of NH3, and SbBr3. In some embodiments, the reactant having a very high dielectric constant may be selected from the group consisting of hydrazine, H2O, and DO.

[0044] In some embodiments, reactants from multiple etching cycles further include one or more purges. In this context, the term "purging" may refer to the act of removing any undesired unreacted products and by-products, as well as 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 reactants 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 reactants 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 reactants and the etching precursor.

[0045] In some embodiments, the first material comprises a material selected from the group consisting of metal oxides, elemental metals, and metal nitrides. In some embodiments, the first material comprises MgO, MgAl x O y, CaO, SrTiO3, BaTiO3, Sc2O3, Y2O3, La2O3, Ce2O3, CeO2, Pr2O3, Nd2O3, SmO, Sm2O3, Gd2O3, Tb2O3, Dy2O3, Ho2 O3, Er2O3, Yb2O3, Lu2O3, TiO2, ZrO2, HfO2, ZrSiO4, HfSiO4, V2O3, VO2, V2O5, Nb2O5, Ta2O5, Cr2O3, MoO3, WO3 , MnO, Mn3O4, Mn2O3, MnO2, MnO3, Mn2O7, FeO, Fe2O3, RuO2, CoO, Co2O3, Co3O4, NiO, Cu2O, CuO, ZnO, Al2O3, Ga2O3, InO, In2O3, SiO2, GeO2, SnO, SnO2, PbO, PbO2, Sb2O3, Sb2O5, Bi2O3, and TeO2. In some embodiments, the first material is an elemental metal selected from the list 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 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, MoNx, WN, W2N, WN x , ReN x , FeN x , RuAl x N y , RuSi x Ny, 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 The metal nitride is selected from the list consisting of:

[0046] In some embodiments, the etch precursor comprises an oxidizing agent or a chlorinating agent. In some embodiments, the oxidizing agent is selected from the group consisting of ozone, oxygen, water, nitrous oxide, and hydrogen peroxide. In some embodiments, the chlorinating agent is selected from the group consisting of phosphorus pentachloride, phosphorus trichloride, phosphoryl chloride, thionyl chloride, sulfuryl chloride, disulfur dichloride, acetyl chloride, oxalyl chloride, N-chlorosuccinimide, and t-butyl hypochlorite.

[0047] 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.

[0048] 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 sulfuryl 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.

[0049] 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 dialkylphosphinic acid chloride (e.g., R2POCl, R = alkyl). In some embodiments, the chlorinating agent is a diarylphosphinic acid 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).

[0050] In some embodiments, the chlorinating agent contains an N-Cl bond, hi some embodiments, the chlorinating agent is N-chlorosuccinimide.

[0051] 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.

[0052] In some embodiments, the etching reactant includes an agent selected from the list consisting of an alkylating agent, cyclopentadiene, an alkylcyclopentadiene, a trimethylsilylcyclopentadiene, an N,N'-dialkylcarbodiimide, a dialkylamine, an alcohol, and a halogenating agent. In some embodiments, the alkylating agent is selected from the group consisting of an alkyl triflate, such as ethyl triflate, a dialkyl carbonate, such as diethyl carbonate, a dialkyl sulfate, such as dimethyl sulfate, trimethylsilyldiazomethane, an alkyl halide, such as diiodomethane, t-butyl iodide, ethyl iodide, 1-chlorohexane, 1-bromobutane, benzyl bromide and benzyl iodide, an aryl halide, such as bromobenzene and iodobenzene, an allyl halide, 3-bromo-1-propene, 3-iodo-1-propene, and 1-bromo-2-butene, and a metal alkyl compound, such as trimethylaluminum, triethylaluminum, diethylzinc, and trimethylgallium. In some embodiments, the dialkylamine is selected from the group consisting of dimethylamine, diethylamine, ethylmethylamine, bis(trimethylsilyl)amine, and diisopropylamine. In some embodiments, the alcohol is selected from the group consisting of methanol, ethanol, isopropanol, tert-butanol, tert-pentanol, trimethylsilanol, and triethylsilanol.

[0053] In some embodiments, the halogenating agent is selected from the list of chlorinating agents recited herein above.

[0054] In some embodiments, the annealing pulse comprises a microwave pulse or an infrared pulse. The purpose of the annealing pulse is to assist in the reaction of a reactant with the surface of the first material or to assist in the formation and / or removal of volatile by-products, thereby driving the etching reaction and allowing the atomic layer etching process to operate under conditions that would otherwise be kinetically slow or thermodynamically unfavorable. The reactant may be, for example, a ligand, a converter, or an etchant of an etching precursor of an etching reactant.

[0055] In some embodiments, the anneal exposure is alternated with a self-limiting reaction of a single reactant. In some embodiments, the anneal exposure is alternated with a self-limiting reaction of two or more reactants that are applied sequentially. In some embodiments, the anneal exposure is simultaneous with the introduction of one reactant in a process in which one or more other reactants are applied sequentially, each of which provides a self-limiting reaction in the atomic layer etch process. In some embodiments, the anneal exposure is simultaneous with the separate introduction of multiple reactants, each of which is applied sequentially to provide a self-limiting reaction in the atomic layer etch process.

[0056] In some embodiments, microwaves are applied at a frequency of 0.3 to 300 GHz, such as 0.5 to 100 GHz, for example, 1 to 20 GHz, or 2 to 5 GHz.

[0057] In some embodiments, the infrared radiation is applied at a wavelength of 0.7 to 1000 μm, such as 1 to 800 μm, for example, 20 to 600 μm, or 30 to 500 μm.

[0058] In some embodiments, the etching cycle is repeated, e.g., at least 1 time, e.g., at least 2 times, e.g., at least 10 times, e.g., at least 20 times, e.g., at least 50 times, e.g., at least 100 times, e.g., at least 500 times, e.g., at least 1000 times, e.g., at least 5000 times.

[0059] 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 can be, for example, 0.1-20 nm, for example, 0.5-15 nm, for example, 1.5-10 nm, for example, 2-7 nm, for example, about 0.5 nm, for example, about 1 nm, for example, about 2 nm.

[0060] In some embodiments, the second material comprises a polymer.

[0061] In some embodiments, the polymer has a dielectric constant of 4.1 or less. The difference in dielectric constant 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 from the substrate. In some embodiments, the polymer is selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, poly(isobutylethylene), polyvinyl fluoride, poly(ethylene), poly(isobutene), 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-phenyl ether), poly(4-chlorostyrene), poly(isobutyl methacrylate), poly(butyl methacrylate), poly(2 ... 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-xylylene), poly(methyl methacrylate), poly(thio-1,4-phenylene), polyvinyl chloride, poly(acrylonitrile), poly[(tetramethylene terephthalate), poly(vinyl acetate), poly(ethylene terephthalate), polyhexamethylene sebacamide, polyhexamethylene adipamide, polyimide, polyamide, and poly(caprolactam).

[0062] Some embodiments provide a method of forming a semiconductor device comprising an etching process as claimed in any one of the preceding claims.

[0063] Some embodiments provide a semiconductor device formed by a method including an etching process according to the present disclosure.

[0064] Some embodiments provide 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, an etching reactant container constructed and arranged to contain an etching reactant, and a generator for heating the substrate by polarization and vibration of water molecules present on the substrate, the generator being arranged outside said etching space and adapted to irradiate the etching space with microwaves or infrared radiation through a continuous wall of said etching space.

[0065] In some embodiments, the generator may 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 at 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 into position anywhere around the etching space to adjust the direction of microwave or infrared radiation toward the substrate. In this way, the generator directs radiation onto the surface of the substrate.

[0066] In some embodiments, the generator is positioned in a separate chamber such that the substrate is first exposed to the etching reactants in the etching space, and then the substrate is moved to a second chamber and exposed to microwave or infrared radiation.

[0067] In some embodiments, the substrate further comprises a second material.

[0068] In some embodiments, the semiconductor processing system further comprises an etch precursor container constructed and arranged to contain the etch precursor.

[0069] In some embodiments, the second material is not removed from the surface of the structure.

[0070] The illustrations presented herein are not meant to be actual representations of any particular materials, structures or devices, but merely idealized representations used to describe embodiments of the present disclosure.

[0071] The particular implementations shown and described are illustrative of the invention and its best modes and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, association, preparation, and other functional aspects of the systems may not be described in detail. Moreover, the connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in an actual system and / or may not be present in some embodiments.

[0072] It should be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be taken in a limiting sense, as numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various illustrated operations may be performed in the order illustrated, or in other orders, or may be omitted in some cases.

[0073] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, as well as other features, functions, operations, and / or properties disclosed herein, as well as all equivalents thereof.

[0074] In some embodiments, the process may be carried out as shown in FIG. 1, which shows a flow chart of atomic layer etching (ALE). In step 111, a film of a first material is deposited on the surface of a substrate 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, preferably conformal deposition. Step 112 is an optional purge step for purging the reaction space. In other words, the purge step rinses the reaction space from 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 pulse of either microwave or infrared light is applied to the substrate. Steps 113, 114, and 115 together form an etching cycle. Steps 113, 114, and 115 may be performed in any order. In some embodiments, an annealing pulse 115 may be performed after both steps 113 and 114. The etching cycle removes at least a portion of the first material. The etching cycle 117 is repeated as many times as necessary. 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 etched completely or to a desired thickness, the process ends (116).

[0075] In some embodiments, the process may be carried out as illustrated in FIG. 2, which shows a flow chart of selective atomic layer etching. In step 211, a film of a first material is deposited on the surface of the substrate by any suitable deposition method, which may be a conformal deposition, preferably. In step 212, a film of a second material is deposited on the substrate. The second material is preferably a polymer having a low dielectric constant. Step 213 is an optional purge step for purging the reaction space. In other words, the purge step rinses the reaction space from 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 pulse of either microwave or infrared light 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 substantial amount of the second material. The etching cycle 218 is repeated as many times as necessary. In some embodiments, the etching cycle is repeated, e.g., 10 times, e.g., 20 times, e.g., 50 times, or e.g., 100 times. After the first material is etched completely or to a desired thickness, the process ends (217).

[0076] FIG. 3 shows a schematic diagram of one cycle of an etching process according to an embodiment of the present invention, where (a) represents the deposition step, (b) represents the pre-etch step, and (c) represents the etching step.

[0077] 3 shows a schematic diagram of one cycle of an etching process according to an embodiment of the present invention, where (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 equal to or greater than a saturation thickness T1, and the etchant film 43 and the first material layer 42 are in contact with each other. The saturation thickness T1 is defined as the thickness, above which the portion of the etchant film does not contribute to the etching of the first material layer, i.e., the amount of etching of the first material layer does not increase even if the thickness of the etchant film is further increased beyond the saturation thickness T1. In the pre-etching step (step (b)), the etchant film 43 is exposed to an annealing agent, such as microwave radiation or infrared radiation, which etches the etchant film and generates gaseous components therefrom that remove the upper portion of the etchant film 43 above the saturation thickness T1.

[0078] As the etching of the etchant film 43 progresses and the etchant film 43 is etched to the saturation thickness T1, the gas component from the etchant film 43 simultaneously generates a gas component from a portion of the first material layer 42 having a depth T2.

[0079] The boundary region 44 consists of the boundary region of the etchant film 43 having a saturation thickness T1 and the boundary region of the first material layer 42 having a depth T2. The total thickness of the boundary region (T1+T2) may depend on the energy during annealing and the pressure of the reaction space. The boundary region 44 may consist of an intermediate, which is composed of mixed components.

[0080] In the etching step (step (c)), the boundary region, or intermediate layer 44, is removed as the gaseous components and the target layer 42 are 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 the steps, these steps rather occur simultaneously.

[0081] 4 illustrates an exemplary embodiment of a semiconductor processing system 200 according to the present disclosure. Additionally, as a schematic representation of the semiconductor processing system 20, many components have been omitted for simplicity of illustration and may include, for example, various inlets, outlets, valves, manifolds, purifiers, heaters, vessels, vents, and / or bypasses.

[0082] The semiconductor processing system 20 comprises an etching space 21, an etching reactant reservoir 22 for holding an etching reactant, an inlet 23 for supplying the etching reactant into the etching space 21, and an outlet 24 for removing the etching reactant from the etching space 21.

[0083] 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.

[0084] The reactant reservoir 22 is constructed and arranged to hold an etching reactant according to the present disclosure. In some embodiments, the semiconductor processing system 20 includes a second, or additional, reactant, or precursor reservoir (not shown). For example, additional oxidizer, or other adjuvant, may be stored in the second reactant reservoir, and the adjuvant may be mixed with the etching reactant as needed.

[0085] Spent etching reactants may be removed from the etching space 21 through an outlet 24. Spent etching solution may be collected in a waste reservoir 25.

[0086] The embodiment of the semiconductor processing system of Fig. 4 further comprises a generator 27 for heating the substrate by polarization and vibration of water molecules present on the substrate. The generator 27 is located outside the etching space 21 and is adapted to apply microwave radiation, or infrared radiation, to said etching space through a continuous wall of the etching space 21.

[0087] The embodiment of the semiconductor processing system of FIG. 4 further comprises a controller 26. The controller 26 includes electronic circuitry and software for selectively operating valves, manifolds, heaters, pumps, and other components included within the semiconductor processing system 20. Such circuitry and components operate to provide fluids, regulate temperature, pressure, and the like to effect proper operation of the semiconductor processing system 20. The controller 26 may include modules, such as software or hardware components, that perform certain tasks. The modules may be configured to reside on addressable storage media of the control system and may be configured to perform one or more processes.

[0088] During operation of the semiconductor processing system 20, one or more substrates, such as semiconductor wafers (not shown), are transferred to the etching space 21. Depending on the configuration of the system 20, an etching solution is provided in the etching space 21 or the substrates are contacted with an etching solution previously present in the etching space 21. [Explanation of symbols]

[0089] 20 Semiconductor Processing Systems 21 Etching Space 22 Etching reactant reservoir 23 Entrance 24 Exit 25 Waste Storage Unit 26 Controller 27 Generator 41 Base material 42 First material layer, target layer 43 Etchant film 44 Boundary area, intermediate layer 45 Etched first material layer

Claims

1. 1. A method of etching a material, comprising the steps of: - providing a substrate in a reaction chamber, said substrate comprising a first material; performing an etching process, comprising etching said first material by performing a plurality of etching cycles, one of said plurality of etching cycles comprising an etching reactant pulse, and an annealing pulse; Including, the etching reactant pulse comprises exposing the substrate to an etching reactant; 13. A method of etching a material, wherein the annealing pulse comprises exposing the substrate to an anneal.

2. - the substrate comprises a device side and a back side, - the first material is located on the device side, - the device side further comprises a second material, The method of claim 1, wherein the etching step comprises selectively etching the first material with respect to the second material.

3. The method of claim 1 , wherein the etching cycle further comprises an etch precursor pulse, the etch precursor pulse comprising exposing the substrate to an etch precursor.

4. The method of claim 1 or 2, wherein the annealing pulse occurs at least partially simultaneously with the etch precursor pulse.

5. The method of any one of claims 1 to 4, wherein the annealing pulse occurs at least partially simultaneously with the etching reactant pulse.

6. The method of any one of claims 1 to 3, wherein one from the plurality of etching cycles further comprises one or more purges.

7. The method of claim 1 , wherein the first material comprises a metal oxide, an elemental metal, or a metal nitride.

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

9. 9. The method of any one of claims 1 to 8, wherein the etching reactants comprise an agent selected from the group consisting of alkylating agents, cyclopentadiene, alkylcyclopentadiene, trimethylsilylcyclopentadiene, N,N'-dialkylcarbodiimides, dialkylamines, alcohols, and halogenating agents.

10. The method of claim 1 , wherein the annealing pulse comprises a microwave pulse or an infrared pulse.

11. The method of claim 10, wherein the microwaves are applied at a frequency of 0.3 to 300 GHz.

12. The method of claim 10, wherein the infrared radiation is applied at a wavelength of 1 to 800 μm.

13. 13. The method of claim 1, wherein the etching cycle is repeated at least twice.

14. The method of 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 of claim 2 , wherein the second material comprises a polymer.

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

17. A method of forming a semiconductor device comprising the etching process of any one of claims 1 to 16.

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

19. 1. 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; an etching reactant reservoir constructed and arranged to contain an etching reactant; a generator for heating the substrate by polarization and vibration of water molecules present on the substrate, the generator being arranged outside the etching space and adapted to apply microwave or infrared radiation to the etching space through a continuous wall of the etching space; A semiconductor processing system comprising:

20. 20. The semiconductor processing system of claim 19, wherein the substrate further comprises a second material.

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