Lower layer doped with dopant for photolithography

Abstract

Examples regarding the use of extreme ultraviolet (EUV) absorbing photoemissive dopants that bind to atoms in a hydrogen contributing photosensitive underlayer for photoresist are disclosed. One example provides a method of forming a hydrogen contributing photosensitive underlayer on a substrate. The method comprises exposing the substrate to a dopant precursor and a hydrocarbon precursor, wherein the dopant precursor comprises an extreme ultraviolet (EUV) absorbing photoemissive dopant bonded within a carbon-containing polymerizable molecule. The method further comprises exposing the substrate to radical species formed by a plasma. The method further comprises forming a hydrogen contributing photosensitive underlayer on the substrate from the dopant precursor and the hydrocarbon precursor by reaction of the dopant precursor and the hydrocarbon precursor with the radical species.

Description

Technical Field

[0001] [Background Art] In photolithography, a photoresist is used to transfer a pattern of light onto a substrate to form a patterned coating. First, a layer of a photosensitive photoresist material is applied onto the substrate. Next, using a patterning mask, the unmasked areas of the photoresist are exposed to light. Exposure can either strengthen a negative photoresist or degrade a positive photoresist. Next, a developer is used to remove the masked areas of the negative photoresist or the degraded areas of the positive photoresist. The remaining photoresist material forms a patterned coating on the substrate. The patterned coating can be used to selectively protect the coated areas of the substrate from, for example, subsequent deposition or etching processes.

Summary of the Invention

[0002] This summary of the invention is provided to introduce a selected simplification of concepts that are further described in the following detailed description for implementing the invention. This summary of the invention 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. Further, the claimed subject matter is not limited to embodiments that solve some or all of the disadvantages described in any part of this disclosure.

[0003] Examples are disclosed relating to the use of extreme ultraviolet (EUV) absorbing photoemissive dopants that bind to atoms in a hydrogen donating photosensitive underlayer for a photoresist.

[0004] One example provides a method of forming a photosensitive lower layer on a substrate. The method includes exposing the substrate to a dopant precursor and a hydrocarbon precursor, where the dopant precursor includes an extreme ultraviolet (EUV) absorbing photoemissive dopant bonded within a carbon-containing polymerizable molecule. The method further includes exposing the substrate to radical species. The method further includes forming a hydrogen-contributing photosensitive lower layer on the substrate from the dopant precursor and the hydrocarbon precursor by reaction of the dopant precursor and the hydrocarbon precursor with the radical species.

[0005] In some such examples, exposing the substrate to radical species includes introducing the radical species into a processing chamber comprising the substrate through an ion / shielding radiation shielding inlet from a remote plasma.

[0006] In some such examples, the dopant precursor is additionally or alternatively introduced downstream of the ion / shielding radiation shielding structure of the ion / shielding radiation shielding inlet.

[0007] In some such examples, the carbon-containing polymerizable molecule additionally or alternatively includes one or more of a carbon-carbon double bond, a carbon-carbon triple bond, or a cyclic group.

[0008] In some such examples, the method further includes, additionally or alternatively, mixing the hydrocarbon precursor with a hydrogen-containing gas before exposing the substrate to the hydrocarbon precursor.

[0009] In some such examples, the dopant precursor additionally or alternatively includes an iodine-containing dopant precursor.

[0010] In some such examples, the iodine-containing dopant precursor additionally or alternatively includes one or more of iodoethyne or 3-iodopropene.

[0011] In some such examples, the dopant precursor additionally or alternatively includes a tin-containing dopant precursor.

[0012] In some such examples, the tin-containing dopant precursor additionally or alternatively comprises one or more of dimethyltin(II), diethyltin(II), tetravinyltin(IV), or dimethyl(di vinyl)tin(IV).

[0013] In some such examples, the ratio of the hydrocarbon precursor gas flow rate in standard cubic centimeters per minute (sccm) to the dopant precursor gas flow rate in sccm is additionally or alternatively in the range of 2:1 to 100:1.

[0014] In some such examples, the method additionally or alternatively further comprises controlling a substrate heater to heat to a temperature within the range of 100 °C to 300 °C.

[0015] Another example provides a patterning stack disposed on a substrate. The patterning stack includes a photoresist layer. The patterning stack further includes a hydrogen-contributing photosensitive underlayer disposed between the photoresist layer and the substrate. The hydrogen-contributing photosensitive underlayer includes an extreme ultraviolet (EUV)-absorbing photoemissive dopant bonded to atoms in the hydrogen-contributing photosensitive underlayer.

[0016] In some such examples, the hydrogen-contributing photosensitive underlayer comprises silicon carbide.

[0017] In some such examples, the hydrogen-contributing photosensitive underlayer additionally or alternatively comprises a polymer.

[0018] In some such examples, the EUV-absorbing photoemissive dopant additionally or alternatively comprises one or more of In, Sn, Sb, Te, or I.

[0019] In some such examples, the photoresist layer additionally or alternatively comprises an extreme ultraviolet (EUV) photoresist.

[0020] In some such examples, the EUV photoresist additionally or alternatively comprises a tin-based metal oxide photoresist.

[0021] Another example provides a processing tool. The processing tool comprises a processing chamber. The processing tool further comprises a plasma generator. The processing tool further comprises a radio frequency power source configured to provide radio frequency power to the plasma generator. The processing tool further comprises flow control hardware configured to control the gas flow to the processing chamber and the plasma generator. The processing tool further comprises a logic subsystem and a storage subsystem containing instructions executable by the logic subsystem to control the flow control hardware to introduce a dopant precursor and a hydrocarbon precursor into the processing chamber, the dopant precursor including an extreme ultraviolet (EUV) absorbing photoemissive dopant bonded within a carbon-containing polymerizable molecule. The instructions are further executable to control the flow control hardware to introduce an inert gas into the plasma generator. The instructions are further executable to control the radio frequency power source to form a plasma in the plasma generator. The instructions are further executable to control the flow control hardware to introduce a radical species precursor into the plasma generator.

[0022] In some such examples, the processing tool further comprises a dopant precursor gas source, the dopant precursor gas source including one or more of an iodine-containing dopant precursor or a tin-containing dopant precursor.

[0023] In some such examples, the processing tool additionally or alternatively further comprises an ion shielding / radiation shielding inlet connecting the plasma generator and the processing chamber.

[0024] In some such examples, the instructions are additionally or alternatively executable to control the flow control hardware to flow the hydrocarbon precursor and the dopant precursor at a gas flow ratio within the range of 2 sccm:1 sccm to 10 sccm:1 sccm.

[0025] In some such examples, the processing tool further comprises, additionally or alternatively, a substrate heater, and the instructions are further executable to control the substrate heater to heat to a temperature within the range of 100°C to 300°C.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0035] The term "aliphatic" can generally represent an organic compound lacking an aromatic group. The term "aliphatic ligand" can generally represent a ligand derived from an aliphatic group from which one hydrogen atom has been removed to enable the ligand to bind to a dopant atom.

[0036] The term "alkane" can generally represent a compound containing the general formula C n H 2n+2 and also substituted straight-chain alkanes. Exemplary alkanes include methane, ethane, propane, and butane. The term "alkyl" can generally represent a functional group having the general formula C n H 2n+1 resulting from removing one hydrogen from an alkane. Exemplary alkyl groups include methyl, ethyl, propyl, and butyl. Exemplary alkyls suitable for use as aliphatic ligands as disclosed herein can include alkyls where n = 1 to 12.

[0037] The term "alkene" can generally represent a hydrocarbon compound containing at least one carbon-carbon double bond. An alkene containing one carbon-carbon double bond has the general formula C n H 2n . Exemplary alkenes include ethene, propene, and butene. Alkenes may have multiple carbon-carbon double bonds such as dienes, allenes, and cumulenes. The term "alkenyl" can generally represent a functional group having the general formula C n H 2n-1 resulting from removing one hydrogen from an alkene. Exemplary alkenyls include vinyl, allyl, propenyl, and butenyl. Exemplary alkenyls suitable for use as unsaturated aliphatic ligands in dopant precursors as disclosed herein can include alkenyls where n = 2 to 12.

[0038] The term "alkyne" can generally represent a hydrocarbon compound containing at least one carbon-carbon triple bond. An alkyne containing one carbon-carbon triple bond has the general formula C n H 2n-2 . An alkyne may have multiple carbon-carbon triple bonds, such as a diyne having two carbon-carbon triple bonds. The term "alkynyl" generally can represent a functional group having the general formula C n H 2n-3 resulting from removing one hydrogen from an alkyne. Exemplary alkynyls include acetylenyl, propynyl, and butynyl. Exemplary alkynyls suitable for use as unsaturated aliphatic ligands in dopant precursors as disclosed herein may include alkynyls where n = 2 to 12.

[0039] The term "aromatic" represents a planar cyclic compound containing resonating pi bonds. The term "aromatic" also includes homocyclic compounds where all atoms in the ring structure are carbon, and heterocyclic compounds where one or more atoms in the ring structure are elements other than carbon (e.g., nitrogen).

[0040] The term "carbon-containing polymerizable molecule" can generally represent aliphatic and aromatic molecules that are capable of binding an extreme ultraviolet (EUV) absorbing photoelectron-emitting dopant and are capable of polymerizing with a hydrocarbon precursor as disclosed herein. Examples of carbon-containing polymerizable molecules include molecules having a carbon-carbon double bond, molecules having a carbon-carbon triple bond, molecules having a cyclic group, and molecules having an aromatic group.

[0041] The term "chemical vapor deposition" can generally represent a process in which a substrate is exposed to one or more gas-phase precursors that react to form a deposited film on the substrate surface.

[0042] The term "cyclic hydrocarbon" generally can represent saturated and unsaturated hydrocarbon molecules containing a closed-ring structure. Cyclic hydrocarbons can be aliphatic or aromatic. Exemplary cyclic hydrocarbons include cyclopropane and cyclobutene. The term "cycloalkyl" generally can represent a functional group resulting from removing one hydrogen from a cycloalkane. Exemplary cycloalkyls suitable for use as carbon-containing polymerizable ligands in dopant precursors as disclosed herein include cyclopropyl, cyclobutyl, and cyclohexyl. The term "cycloalkenyl" generally can represent a functional group resulting from removing one hydrogen from a cycloalkene. Exemplary cycloalkenyls suitable for use as aliphatic ligands in dopant precursors as disclosed herein include cyclobutenyl and cyclohexenyl. The term "cyclic group" generally can represent a functional group containing a cyclic hydrocarbon.

[0043] The term "dopant precursor" generally can represent any suitable compound containing an EUV-absorbing photoemissive dopant bonded within a carbon-containing polymerizable molecule that can react with a hydrocarbon precursor to form a hydrogen-donating photosensitive underlayer. Exemplary EUV-absorbing photoemissive dopants suitable for use in a hydrogen-donating photosensitive underlayer include indium (In), tin (Sn), antimony (Sb), tellurium (Te), and iodine (I). The dopant precursor has the general formula Z-R n, n can be ≥ 1, Z is any suitable EUV absorbing element that emits EUV photoelectrons, R generally represents a ligand, one or more of which contain carbon-containing molecules. Each R can independently be, for example, hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkenyl, or substituted cycloalkenyl. Suitable alkyl ligands include methyl, ethyl, propyl, and t-butyl. Suitable substituted alkyls include iodoethyl and aminopropyl. Suitable cycloalkyl ligands include cyclopropyl groups and cyclobutyl groups. Suitable substituted cycloalkyl ligands include aminocyclohexyl. Suitable alkenyl ligands include vinyl (ethenyl), allyl, propenyl, and 3-butenyl. Suitable substituted alkenyl ligands include aminovinyl. Suitable alkynyl ligands include ethynyl and propynyl. Suitable substituted alkynyl ligands include chloropropynyl. Suitable cycloalkenyl ligands include cyclobutenyl and cyclohexenyl.

[0044] Exemplary dopant precursors that may be suitable for forming a hydrogen contribution photosensitive lower layer include organoantimony compounds (e.g., Sb(V) compounds having the general formula R 5 Sb and Sb(III) compounds having the general formula R 3 Sb), organotin compounds (e.g., Sn(IV) compounds having the general formula R 4 Sn), organotellurium compounds (e.g., telluride compounds having the general formula R 2 Te or (RTe) 2 , Te(IV) compounds having the general formula R 4 Te, and general formula R 2Tellurium oxide having TeO, and organic iodine compounds of the general formula R-I. Exemplary dopant precursors include tin-containing dopant precursors (such as tetravinyltin(IV), tetraethynyltin(IV), diethyltin(II), dimethyltin(II), and dimethyldivinyltin(IV)), antimony-containing dopant precursors (such as trivinylantimony), tellurium-containing dopant precursors (such as divinyl telluroxide), and iodine-containing dopant precursors (such as iodoethyne, 3-iodopropene, and 3-iodopropyne).

[0045] The term "extreme ultraviolet (EUV) absorbing photoelectron emitting dopant" can generally represent any atom that absorbs radiation having a wavelength in the range of 124 nanometers (nm) to 10 nm and emits photoelectrons in response thereto. Exemplary EUV absorbing photoelectron emitting dopants suitable for use in the lower layer include indium (In), antimony (Sb), tin (Sn), tellurium (Te), and iodine (I).

[0046] The term "EUV photolithography process" can generally represent a photolithography process in which a photoresist sensitive to EUV light is exposed to EUV light. The term "EUV photoresist" can generally represent a photoresist material sensitive to EUV light. EUV refers to light having a wavelength of about 124 nm to about 10 nm and a photon energy of 10 eV to 124 eV.

[0047] The term "functional group" can generally represent an atom or group of atoms in a molecule.

[0048] The term "inlet" can generally represent any structure for injecting a gaseous chemical substance or plasma into the processing chamber of a processing tool. The inlet can be provided with a nozzle or a showerhead in various examples.

[0049] The term "hydrocarbon precursor" can generally represent any carbon-containing precursor that is polymerizable to form a hydrogen-donating photosensitive lower layer on a substrate. Exemplary hydrocarbon precursors include unsaturated aliphatic compounds and cycloaliphatic compounds. For example, when a carbon polymer matrix is deposited, exemplary unsaturated aliphatic compounds include acetylene, propylene, ethene, and propene. For example, when silicon carbide or polycarbosilane is deposited, a silicon-containing precursor may be used in addition to the carbon-containing precursor. In some examples, the hydrocarbon precursor may include a mixture of gases and may be further mixed with a hydrogen-containing gas.

[0050] The term "hydrogen-donating photosensitive lower layer" can generally represent a material that generates labile hydrogen that can migrate to an upper layer (such as a photoresist layer) when exposed to light of an appropriate wavelength. Materials suitable for use as a hydrogen-donating photosensitive lower layer include carbon-based polymers and silicon carbide-based layers.

[0051] The term "ion / radiation shielding inlet" can generally represent an inlet configured to allow a flow of radical species to pass through while filtering at least some ions and electromagnetic radiation from a plasma. In some examples, the ion / radiation shielding inlet can comprise an ion / radiation shielding showerhead. The term "showerhead" can generally represent an inlet comprising a plurality of holes configured to introduce a process gas over an entire region of a substrate.

[0052] The term "labile hydrogen" can generally represent hydrogen molecules, hydrogen atoms, or hydrogen ions entrained from a hydrogen-donating photosensitive lower layer to a photoresist layer. Labile hydrogen can also represent hydrogen atoms, ions, and / or radicals generated in a hydrogen-donating photosensitive lower layer by EUV light exposure and capable of migrating to the photoresist layer.

[0053] The term "ligand" can generally represent a functional group that binds to a central metal atom to form a coordination complex.

[0054] The term "free EUV absorption photoemission dopant" generally can represent an EUV absorption photoemission dopant species in a hydrogen-contributing photosensitive lower layer that is not bound to an atom. The free EUV absorption photoemission dopant may include elemental species, ionic species, and / or radical species.

[0055] The term "patterning stack" generally can represent a hydrogen-contributing photosensitive lower layer disposed on a substrate and a photoresist layer disposed on the hydrogen-contributing photosensitive lower layer.

[0056] The term "photoresist" generally can represent a photosensitive material that can be used to transfer a pattern to a substrate through radiation-induced changes in material properties.

[0057] The term "photosensitive lower layer" generally can represent a material that undergoes a chemical change when exposed to photons of electromagnetic energy of an appropriate wavelength.

[0058] The term "plasma" generally can represent an ionized gas containing cations and free electrons. The plasma can be generated using any suitable method and can include radio frequency (RF) plasma, microwave plasma, and electron beam generated plasma. It is possible to generate radical species using plasma. For example, a hydrogen-containing gas (e.g., H 2 , NH 3 , N 2 H 4 ) can be introduced into the plasma to generate hydrogen radicals, which are hydrogen atoms with unpaired electrons.

[0059] The term "processing chamber" generally can represent an enclosure in which chemical and / or physical processes are performed on a substrate. Exemplary chemical and / or physical processes include chemical vapor deposition (CVD), atomic layer deposition (ALD), and etching processes.

[0060] The term "processing tool" can generally represent a machine that includes a processing chamber and other hardware configured to enable processing to be performed on one or more substrates within the processing chamber.

[0061] The term "radical species" can generally represent a chemical species having unpaired valence electrons.

[0062] The term "remote plasma" can generally represent a plasma used to generate chemical species for processing a substrate located outside the plasma.

[0063] The term "silicon-containing precursor" can generally represent any silicon-containing material that can be introduced together with a hydrocarbon precursor to deposit silicon carbide or polycarbosilane. Exemplary silicon-containing precursors for forming silicon carbide or polycarbosilane can include materials having the following general structure: [Chemical formula] R 1 、R 2 、and R 3 may be the same or different substituents and may include silane, siloxy group, amine, halide, hydrogen, or an organic group such as alkylamine, alkoxy, alkyl, alkenyl, alkynyl, and aromatic group.

[0064] Exemplary silicon-containing precursors can include polysilanes such as silane, disilane, trisilane, tetrasilane, and trisilylamine (H 3 Si-(SiH 2 ) n -SiH 3 )(n≧1).

[0065] In some examples, the silicon-containing precursor is an alkoxysilane. Examples of alkoxysilanes that can be used include: H x -Si-(OR) y, x = 1 to 3, x + y = 4, and each R is a substituted or unsubstituted alkyl, alkenyl, alkynyl, or aromatic group, H x (RO) y , -Si-Si-(OR) y H x is a substituted or unsubstituted alkyl, alkenyl, alkynyl, or aromatic group.

[0066] Examples of silicon-containing precursors include tetraethyl orthosilicate (TEOS), tetramethoxysilane (TMOS), methylsilane, trimethylsilane (3MS), ethylsilane, butasilane, pentasilane, octasilane, heptasilane, hexasilane, cyclobutasilane, cycloheptasilane, cyclohexasilane, cyclooctasilane, cyclopentasilane, 1,4-dioxa-2,3,5,6-tetrasilacyclohexane, diethoxymethylsilane (DEMS), diethoxysilane (DES), dimethoxymethylsilane, dimethoxysilane (DMOS), methyldiethoxysilane (MDES), methyldimethoxysilane (MDMS), t-butoxydisilane, triethoxysilane (TES), and trimethoxysilane (TMS or TriMOS).

[0067] In some examples, the silicon-containing precursor may be a siloxane. Exemplary siloxanes include octamethylcyclotetrasiloxane (OMCTS), octamethoxydodecasiloxane (OMODDS), tetramethylcyclotetrasiloxane (TMCTS), triethoxysiloxane (TRIES), and tetraoxymethylcyclotetrasiloxane (TOMCTS).

[0068] As described above, in some examples, the silicon-containing precursor may be an aminosilane, such as bisdiethylaminosilane, diisopropylaminosilane, bis(t-butylamino)silane (BTBAS), di-sec-butylaminosilane, or tris(dimethylamino)silane (3DMAS). Examples of aminosilane precursors include: H x -Si-(NR)y 、x = 1 to 3, x + y = 4, and R is a substituted or unsubstituted alkyl, alkenyl, alkynyl, or aromatic group or hydride group.

[0069] In some examples, the halogen-containing silane can be used such that the silane contains at least one hydrogen atom. Such silanes can have the chemical formula SiX a H y (y ≥ 1). For example, dichlorosilane (H 2 SiCl 2 ) can be used in some examples.

[0070] The term "substrate" generally can represent any structure on which a patterning stack can be formed. Exemplary substrates include semiconductor wafers.

[0071] As described above, photolithography can be used to form a patterned coating on a substrate. In an exemplary process, a photoresist material is applied to the substrate. For example, a wet photoresist can be applied using a spin-on method. It is also possible to apply a dry photoresist using a vapor deposition method. Next, the photoresist material is exposed to a pattern of light formed by patterning a mask. As a result, some regions of the photoresist are exposed to light and other regions are masked from the exposure. The exposed regions undergo a chemical reaction, resulting in a structural difference between the exposed regions compared to the non-exposed regions. Next, the structural difference between the exposed and non-exposed regions is utilized to partially remove the coating. The remaining coating forms a pattern on the substrate.

[0072] In the manufacture of semiconductor devices, photolithography is used for many different steps in the fabrication of integrated circuits. The minimum feature size that can be resolved by photolithography can be approximated using the Rayleigh equation as follows.

Equation

[0073] Extreme ultraviolet (EUV) lithography is a promising technology for patterning integrated circuits with line-and-space pitches less than 36 nanometers (nm). EUV refers to light spanning wavelengths from approximately 124 nm to approximately 10 nm and photon energies from 10 eV to 124 eV. In some examples, EUV light can be generated using, for example, a laser-driven tin (Sn) plasma light source. Such a light source can generate light having a peak at approximately 13.5 nm and a relatively narrow bandwidth. When EUV light is absorbed, an EUV-sensitive photoresist generates photoelectrons, which drive chemical reactions in the exposed regions of the photoresist. EUV-sensitive photoresists suitable for λ = 13.5 nm may include metal-containing photoresists such as metal oxide photoresists, metal oxide nanoparticle photoresists, and organometallic photoresists (e.g., photoresists containing Zn, Zr, Sn, Sb, Te, and / or Hf).

[0074] However, EUV photoresists may have high sensitivity. Furthermore, the optical system used in EUV lithography absorbs a portion of the incident light. Thus, only a relatively small portion of the generated EUV light may reach the photoresist. Due to the intensity of the incident EUV light and the high sensitivity, a relatively long exposure time may be required to generate features in the photoresist. The longer the exposure time, the more the throughput may decrease. Furthermore, when the exposure time becomes long, heating of the substrate may occur. This may cause gas release from the substrate and / or damage to the substrate. Additionally, the transition region of the photoresist (the region located between the fully exposed region and the fully masked region) may receive a relatively low dose (energy amount per unit area) of EUV light. This may result in fewer well-defined features in the transition region.

[0075] One way to reduce the exposure time of EUV photoresists is to utilize a hydrogen-contributing photosensitive underlayer positioned between the substrate and the EUV photoresist layer. The hydrogen-contributing photosensitive underlayer generates labile hydrogen when exposed to EUV light and / or post-exposure bake. The labile hydrogen may migrate to the EUV photoresist layer. The labile hydrogen promotes the desorption reaction of water and can result in crosslinking in metal oxide photoresists. For example, in a tin-based metal oxide EUV photoresist, the labile hydrogen may inhibit the recombination of hydroxyl groups with tin atoms, thereby enabling tin to form Sn-O-Sn bonds that crosslink the tin metal oxide polymer chains. Thus, the labile hydrogen may enable crosslinking to occur with a shorter EUV light exposure time.

[0076] To further reduce the exposure time, an EUV-absorbing photoemissive dopant can be incorporated into the hydrogen-contributing photosensitive underlayer. The EUV-absorbing photoemissive dopant can emit EUV photoelectrons when it absorbs EUV light. Thereby, additional electrons can be provided to drive chemical reactions in the photoresist. Furthermore, the photoelectrons generated by the EUV-absorbing photoemissive dopant can also drive the generation of additional labile hydrogen. Each of these mechanisms can help shorten the exposure time of the photoresist.

[0077] However, some EUV-absorbing photoemissive elements (e.g., especially Sn) may be prone to forming hydrides. For example, free EUV-absorbing photoemissive dopants that are not bonded to atoms may form hydrides from labile hydrogen. This is shown in FIGS. 1A-1B. More specifically, FIG. 1A shows a hydrogen-contributing photosensitive underlayer 102 disposed on a substrate 103. An EUV photoresist layer 104 is disposed on the hydrogen-contributing photosensitive underlayer 102. The free EUV-absorbing photoemissive dopant shown as Sn atoms 306 is not bonded to atoms in the hydrogen-contributing photosensitive underlayer. Thus, the Sn atoms 306 can capture one or more labile hydrogen atoms as shown at 308. Thereby, stannous hydride can be formed as shown in FIG. 1B. Thus, free EUV photoemissive dopants can potentially adversely affect the function of the hydrogen-contributing photosensitive underlayer by capturing labile hydrogen.

[0078] Accordingly, examples regarding the use of a hydrogen-contributing photosensitive lower layer including a combined EUV-absorbing photoemissive dopant are disclosed. In one example, a patterning stack formed on a substrate includes a photoresist layer and a hydrogen-contributing photosensitive lower layer including an EUV-absorbing photoemissive dopant bonded to atoms in the hydrogen-contributing photosensitive lower layer. The hydrogen-contributing photosensitive lower layer is disposed between the substrate and the photoresist layer. At least a portion of the EUV light not absorbed by the photoresist layer can be absorbed by the EUV-absorbing photoemissive dopant in the hydrogen-contributing photosensitive lower layer. In response, the EUV-absorbing photoemissive dopant can generate photoelectrons that assist in driving the crosslinking reaction in the photoresist. The photoelectrons may also generate additional labile hydrogen that promotes the crosslinking reaction in the photoresist. The bonding of the EUV-absorbing photoemissive dopant to atoms in the hydrogen-contributing photosensitive lower layer can reduce the risk of forming dopant hydrides from the labile hydrogen in the hydrogen-contributing photosensitive lower layer. Avoiding the formation of dopant hydrides can allow more labile hydrogen and photoelectrons to reach the photoresist layer. Accordingly, the disclosed examples may help improve throughput by reducing the exposure time of the photoresist. The disclosed examples may also help form features clearly defined in the transition region.

[0079] The hydrogen donating photosensitive underlayer according to the present disclosure can be formed using a dopant precursor and a hydrocarbon precursor. The dopant precursor includes an EUV absorbing photo electron emitting dopant bonded within a carbon-containing polymerizable molecule. The dopant precursor can react with the hydrocarbon precursor in a polymerization reaction. The polymerization reaction can be promoted by radical species formed by a plasma. However, plasma ions and / or plasma energy can pose a risk of cleaving the carbon-dopant bond of the dopant precursor. Thus, in some examples, a remote plasma can be used to form radical species. In such examples, an ion / shielding radiation shielding inlet can be used to introduce the radical species into the processing chamber. The ion / shielding radiation shielding inlet can help reduce the risk of high energy ions and electromagnetic radiation from the plasma damaging the dopant precursor.

[0080] Figures 2A-2C show the patterning stack 200 at various stages in an EUV lithography process. Figures 3A-3D show corresponding exemplary chemical reactions for an exemplary tin-based metal oxide photoresist. Referring first to Figure 2A, the patterning stack 200 includes a photoresist layer 202 and a hydrogen donating photosensitive underlayer 204 disposed on a substrate 206. The substrate 206 represents any suitable structure on which the photoresist layer 202 and the hydrogen donating photosensitive underlayer 204 can be formed. The hydrogen donating photosensitive underlayer 204 includes an EUV absorbing photo electron emitting dopant (schematically shown at 208) bonded to a carbon atom.

[0081] The photoresist layer 202 can include any suitable EUV-sensitive photoresist, including wet photoresist and dry photoresist. The wet photoresist may include a photoresist applied in a liquid phase. The dry photoresist may include a photoresist applied by depositing reactive precursors in a gas phase. In some examples, the photoresist layer 202 may include a tin-based metal oxide photoresist that can form Sn-O-Sn crosslinks, as described in more detail below. The hydrogen-donating photosensitive underlayer 204 can include any suitable material for providing labile hydrogen to the photoresist layer 202. For example, the hydrogen-donating photosensitive underlayer 204 may include a carbon-based polymer or a silicon carbide-containing material in various examples. Thus, in some examples, the EUV-absorbing photoemissive dopant can be bonded to any suitable atom (e.g., N, C, Si) within the hydrogen-donating photosensitive underlayer.

[0082] The EUV-absorbing photoemissive dopant can include any suitable atom having a relatively high absorption cross-section for EUV light. A suitable EUV absorption cross-section includes a cross-section of 1×10 7 cm 2 / mol or greater. Exemplary EUV-absorbing photoemissive dopants suitable for use in the hydrogen-donating photosensitive underlayer include In, Sn, Sb, Te, and I.

[0083] Continuing with FIG. 2A, the region 202A of the photoresist layer 202 is exposed to EUV light 210. The region 202B is masked from exposure by a patterning mask (not shown). When the region 202A of the photoresist layer 202 and the hydrogen-donating photosensitive underlayer 204 are exposed to EUV light, the hydrogen-donating photosensitive underlayer contributes labile hydrogen to the photoresist layer 202. Referring now to FIG. 2B, the labile hydrogen reacts with the photoresist to form a chemically modified photoresist region 202C. An exemplary reaction of a tin oxide-based photoresist with labile hydrogen will be described below with respect to FIGS. 3A-3B.

[0084] Furthermore, exposure to the EUV-absorbing photoemission dopant 208 results in the emission of photoelectrons. Some of the photoelectrons may generate additional labile hydrogen through desorption by electron impact (e.g., through bond cleavage), as indicated by 222. In addition, some of the photoemission dopants can generate photoelectrons that migrate to the photoresist layer 202, as indicated by 224. Such photoelectrons can increase the photon dose of the EUV light exposure. Through either or both of these mechanisms, the photoelectrons generated by the EUV-absorbing photoemission dopant can help shorten the exposure time used to form the chemically modified photoresist region 202C.

[0085] Next, the photoresist layer 202 containing the chemically modified photoresist region 202C undergoes a post-exposure bake (PEB). The PEB process drives labile hydrogen into the photoresist layer 202. This results in the desorption reaction of water and crosslinking of the photoresist molecules in the chemically modified photoresist region 202C. Referring now to FIG. 2C, as a result, a crosslinked photoresist region 202D is formed. The subsequent development process can be used to remove the region 202B of the photoresist film. Thus, the development process forms a patterned photoresist film that includes the crosslinked photoresist region 202D.

[0086] The EUV photolithography process shown in FIGS. 2A-2C can be implemented using various photoresist chemistries. FIGS. 3A-3D illustrate the process of FIGS. 2A-2C implemented on an exemplary tin-based metal oxide EUV photoresist layer 300. First, FIG. 3A shows the molecular structure of an exemplary tin-based metal oxide EUV photoresist layer 300. The tin-based metal oxide EUV photoresist layer 300 includes a tin metal oxypolymer chain 302 (illustrated as a Sn—O—Sn polymer chain) having a functional group (R) 304 bonded to the Sn atom. The functional group 304 can include any suitable functional group capable of undergoing a β-hydride elimination reaction. For example, the functional group 304A includes an ethyl group capable of undergoing β-hydride elimination to form ethene. FIG. 3A also shows an interface 306 between the tin-based metal oxide EUV photoresist layer 300 and a hydrogen-donating photosensitive underlayer 308 including a carbon polymer-based structure. The hydrogen-donating photosensitive underlayer 308 includes one or more EUV-absorbing photoemissive dopant atoms 310 bonded to carbon atoms of the carbon polymer-based structure. The hydrogen-donating photosensitive underlayer 308 further includes entrained hydrogen including hydrogen molecules (H 2 ) 312A, radical hydrogen (H−) 312B, and hydrogen ions (H + ) 312C. Further, the carbon polymer-based structure includes H atoms bonded to carbon such as H 314.

[0087] Referring next to FIG. 3B, when the structure of FIG. 3A is exposed to EUV light 210, unstable hydrogen 316 is generated in the hydrogen-donating photosensitive underlayer 308. The unstable hydrogen can include entrained hydrogen such as H 2 312A, H 312B, and H + 312C. Further, the photoelectrons generated by the EUV-absorbing photoemissive dopant atoms 310 can generate additional unstable hydrogen. For example, as shown at 316, the photoelectrons generated by the EUV-absorbing photoemissive dopant atoms 310 can generate unstable hydrogen 314A from the hydrogen 314 of the backbone 318 of the carbon-based polymer structure.

[0088] The photoelectrons generated by the EUV-absorbing photoemissive dopant atoms 310 can also move to the tin-based metal oxide EUV photoresist layer 300, as indicated by the photoelectrons 320. Upon exposure to EUV light 110 and photoelectrons (e.g., photoelectrons 320) from the hydrogen-contributing photosensitive underlayer 308, the bond between Sn and the functional group 304 is cleaved. As shown in Figure 3B, the functional group 304 is replaced by H. For example, the ethyl group 304A undergoes β-hydride elimination to form ethene 304B and donate H as shown at 322. The chemically modified tin oxide-based EUV photoresist of Figure 3B can represent the chemically modified photoresist region 202C of Figure 2B.

[0089] In some examples, the R functional group 304 may be relatively bulky. Thus, by replacing the R functional group with hydrogen, the tin metal oxy polymer chains can be brought closer to each other. This can facilitate crosslinking by water elimination.

[0090] As shown in Figure 3B, water molecules can be eliminated from adjacent hydroxyl groups 324 of the tin metal oxy polymer chains to crosslink the adjacent chains. Figure 3C shows the result of water elimination 325 in the crosslinked structure 326. As shown in Figure 3C, heat 328 is applied to assist in removing water from the crosslinked structure 326. As shown at 330, heat 328 may also help promote the movement of labile hydrogen to the photoresist layer. In the example shown, the labile hydrogen can potentially inhibit the recombination of the hydroxyl group with the tin atom (e.g., by shifting the equilibrium between the Sn-O-Sn linkage and the -OH-terminated Sn), which, in combination with the evaporation of water, drives tin to form Sn-O-Sn bonds. As shown in Figure 3D, the crosslinked structure 326 includes Sn-O-Sn bonds 332 between the tin metal oxy polymer chains. The crosslinked structure 326 is an example of the crosslinked photoresist region 202D of Figure 2C.

[0091] As shown in FIGS. 2A - 2C and FIGS. 3A - 3D, the use of EUV - absorbing photo - electron - emitting dopants in the hydrogen - donating photosensitive lower layer can help shorten the exposure time for EUV photoresists. However, as described above with respect to FIGS. 1A - 1B, the use of free EUV - absorbing photo - electron - emitting dopants can cause the formation of dopant hydrides from labile hydrogen.

[0092] In contrast to FIGS. 1A - 1B, FIG. 4 shows a substrate 401 on which a hydrogen - donating photosensitive lower layer 402 containing a dopant (such as Sn atom 404) bonded to a carbon atom is disposed. As described above, labile hydrogen atoms 406 may be accompanied by H 2 , H, or H + contained, or may be generated from carbon - based polymer chains in the hydrogen - donating photosensitive lower layer. The labile hydrogen atoms 406 can move to the photoresist layer 408 without being captured by the Sn atoms in the hydrogen - donating photosensitive lower layer 402. Although Sn is used in the examples illustrated in FIGS. 1A - 1B and FIG. 4, any other suitable EUV - absorbing photo - electron - emitting dopant containing In, Sb, Te, and / or I may be used.

[0093] A hydrogen - donating photosensitive lower layer containing an EUV - absorbing photo - electron - emitting dopant bonded to an atom can be formed in any suitable manner. In some examples, the hydrogen - donating photosensitive lower layer can be formed by chemical vapor deposition. In an exemplary process, the above - mentioned hydrocarbon precursor and dopant precursor can be introduced into a processing chamber containing a substrate, and the hydrogen - donating photosensitive lower layer can be formed by polymerization. In some examples, it is possible to heat the substrate.

[0094] Furthermore, in some examples, the polymerization may be radical-assisted. Any suitable radical source can be used. In some such examples, a plasma can be used to form radical species that initiate the polymerization. However, ions and radiation from the plasma may have sufficient energy to break the ligand-dopant bonds in the dopant precursor. Thus, in some examples, the injection of the dopant precursor into the processing chamber can be separated from the injection of radical species by using a remote plasma and an ion / shielding radiation shielding inlet for introducing the radical species generated in the plasma into the processing chamber.

[0095] FIG. 5 shows a schematic diagram of an exemplary processing tool 500 for forming a hydrogen contribution photosensitive lower layer including an EUV absorption photoelectron emitting dopant using an ion / shielding radiation shielding inlet. The processing tool 500 includes a processing chamber 502 and a substrate support 504 within the processing chamber. The substrate support 504 is configured to support a substrate 506 disposed within the processing chamber 502. In some examples, the substrate support 504 includes a substrate heater 508. The substrate support 504 may comprise a pedestal, a chuck, and / or any other suitable structure.

[0096] The processing tool 500 further includes an ion / shielding radiation shielding inlet 510. The ion / shielding radiation shielding inlet 510 is configured to introduce a precursor gas and radical species into the processing chamber 502 while filtering ions and radiation generated by a remote plasma generator 530, as described in more detail below. In some examples, the ion / shielding radiation shielding inlet 510 includes a showerhead.

[0097] The processing tool 500 further includes flow control hardware 514A-B. The flow control hardware 514A is connected to a dopant precursor source 516, a hydrocarbon precursor source 518, and a hydrogen gas source 520. In the example illustrated in FIG. 5, the hydrogen gas source 520 can be used as a radical precursor. In some examples, any suitable hydrogen-containing gas (e.g., H 2, NH 3 , or N 2 H 4 ) can be used as a radical precursor. The flow control hardware 514B is connected to an inert gas source 522. The flow control hardware 514B is configured to control the flow of hydrogen-containing gas from the hydrogen gas source 520 and / or inert gas from the inert gas source 522 to the remote plasma generator 530. The hydrocarbon precursor source 518 can include any suitable polymerizable hydrocarbon for forming a hydrogen-donating photosensitive lower layer. Exemplary hydrocarbon precursors are described in more detail above.

[0098] The dopant precursor source 516 may include any suitable dopant precursor that, when reacted with the hydrocarbon precursor, forms a hydrogen-donating photosensitive lower layer containing an EUV-absorbing photoemissive dopant bonded to an atom (e.g., a carbon atom of the hydrocarbon precursor). As described above, the dopant precursor may include a dopant atom bonded within a carbon-containing polymerizable molecule. Exemplary dopant precursors include tin-containing dopant precursors such as tetravinyltin(IV), tetraethynyltin(IV), diethyltin(II), dimethyltin(II), and dimethyl(di vinyl)tin(IV). In some examples, exemplary dopant precursors further include iodine-containing precursors such as iodoethyne, 3-iodopropene, and 3-iodopropyne. Further examples include precursors containing In, Sb, and Te bonded to a carbon-containing polymerizable molecule. Exemplary carbon-containing polymerizable molecules include, among others, the vinyl, ethynyl, allyl, propenyl, butenyl, and cyclopropyl ligands described above.

[0099] The dopant precursor and the hydrocarbon precursor are configured to react by polymerization to form a hydrogen-donating photosensitive lower layer on the substrate. As described above, the hydrogen-donating photosensitive lower layer contains a bonded EUV-absorbing photoemissive dopant. Further, hydrogen gas from the hydrogen source 520 may be introduced.

[0100] Figures 6-7 show exemplary polymerization reactions for forming a hydrogen-contributing photosensitive lower layer including a combined EUV-absorbing and photoemitting dopant. First, FIG. 6 shows an exemplary polymerization reaction 600 between a dopant precursor 602 and a hydrocarbon precursor 604. The dopant precursor 602 includes tetravinyltin(IV). The hydrocarbon precursor 604 includes propene. The dopant precursor 602 and the hydrocarbon precursor 604 react to form a tin-containing polymer hydrocarbon 606. The polymerization reaction 600 can be promoted by radical species 608. The radical species 608 can be any suitable radical species. Examples include radicals generated from hydrogen (H 2 ), deuterium (D 2 ), ammonia (NH 3 ), and / or hydrazine (N 2 H 4 ) in a plasma. The radical species 608 can be formed by a plasma such as a remote plasma. The tin-containing polymer hydrocarbon 606 includes Sn-C bonds such as bond 610. Thus, when used as a hydrogen-contributing photosensitive lower layer, the tin atoms in the tin-containing polymer hydrocarbon 606 can help generate EUV photoelectrons without capturing labile hydrogen.

[0101] Next, FIG. 7 shows an example of a polymerization reaction 700 between a dopant precursor 702 including 3-iodopropene and a hydrocarbon precursor 704 including propene. The dopant precursor 702 and the hydrocarbon precursor 704 react to form an iodine-containing polymer hydrocarbon 706. The reaction can be promoted by radical species 708. Examples of radical species include radicals formed from one or more of hydrogen, deuterium, ammonia, or hydrazine in a plasma. As shown by bond 710, the polymer hydrocarbon 706 includes an iodine-carbon (I-C) bond. Thus, when used as a hydrogen-contributing photosensitive lower layer, the iodide (I) atoms in the polymer hydrocarbon 706 can help generate EUV photoelectrons without capturing labile hydrogen. In other examples, any suitable dopant precursor and any suitable hydrocarbon precursor may be used.

[0102] Returning to FIG. 5, the flow control hardware 514A can be controllable to flow gases from the dopant precursor source 516, the hydrocarbon precursor source 518, and the hydrogen gas source 520 into the processing chamber 502 to deposit the hydrogen-contributing photosensitive lower layer. Ions and / or radiation from the remote plasma generator 530 are filtered by the ion shielding / radiation shielding inlet 510 before being introduced into the processing chamber 502. In the example of FIG. 5, the chemicals are introduced from the side of the processing chamber 502. Thus, the precursor gas is introduced downstream from the ion shielding / radiation shielding inlet 510. Introducing the dopant precursor downstream from the ion shielding / radiation shielding inlet 510 can help filter ions and / or high-energy radiation and prevent cleavage of the bond between the EUV-absorbing photoelectron-emitting dopant and the carbon-containing polymerizable ligand in the dopant precursor. When hydrogen is introduced from the hydrogen gas source 520 into the chamber downstream of the ion shielding / radiation shielding inlet 510, the entrained hydrogen is introduced into the hydrogen-contributing photosensitive lower layer. In some examples, the entrained hydrogen can be introduced into the hydrogen-contributing photosensitive layer via the flow control hardware 514B and the remote plasma generator 530. In such examples, the connection of the hydrogen source 520 to the flow control hardware 514A can be omitted.

[0103] The remote plasma generator 530 is configured to generate a remote plasma from an inert gas and a radical precursor to generate radical species. In some examples, the remote plasma generator 530 can be configured to generate an inductively coupled plasma (ICP). In other examples, the remote plasma generator 530 can be configured to generate a capacitively coupled plasma (CCP). In further examples, a microwave plasma may be used. The radical species can flow into the processing chamber through the ion shielding / radiation shielding inlet 510. Suitable inert gases include He, Ne, Ar, Kr, and N2. Suitable radical precursors include hydrogen, deuterium, ammonia, and hydrazine. The flow control hardware 514A - B schematically represents any suitable components related to the inflow of gas into the processing chamber 502.

[0104] The flow control hardware 514A - B can include one or more mass flow controllers and / or valves for controlling the flow rate of the gas. In some examples, the flow control hardware can be controlled to adjust the flow rate ratio between two gases. For example, the flow control hardware can be controlled to flow the hydrocarbon precursor and the dopant precursor at a gas flow rate ratio in the range of 2:1 to 100:1, measured in standard cubic centimeters per minute (sccm).

[0105] In some examples, a liquid precursor can be used for the dopant precursor source 516 and / or the hydrocarbon precursor source 518. In such examples, the liquid precursor can be introduced with a carrier gas as a flow - over vapor (FOV). In such examples, the flow control hardware 514A can be configured to introduce the liquid precursor into the processing chamber using the FOV.

[0106] The processing tool 500 further includes an exhaust system 532. The exhaust system 532 is configured to receive the gas flowing out of the processing chamber 502. In some examples, the exhaust system 532 is configured to actively remove the gas from the processing chamber 502 and / or apply a partial vacuum. The exhaust system 532 can include any suitable hardware including one or more pumps.

[0107] As described above, the remote plasma generator 530 is configured to form radical species using plasma. The radical species can facilitate the reaction between the dopant precursor and the hydrocarbon precursor. For example, the radicals can initiate polymerization by reacting with unsaturated carbon-carbon bonds and / or by opening cyclic functional groups. The plasma can be formed from a gas supplied by the inert gas source 522. In the illustrated example, hydrogen from the hydrogen gas source 520 acts as a radical precursor. In other examples, radical precursors other than hydrogen may be used. As described above, suitable radical precursors include hydrogen, deuterium, ammonia, and hydrazine. The inert gas source 522 can include any suitable inert gas such as He, N 2 , Ne, Ar, or Kr. In some more specific examples, an H / He plasma is used.

[0108] The processing tool 500 further includes a radio frequency (RF) power source 534 electrically connected to the remote plasma generator 530. The processing tool 500 may further include a matching network 536 for impedance matching of the RF power source 534. The RF power source 534 can be configured for any suitable frequency and power. Examples of suitable frequencies include frequencies in the range of 0.3 MHz to 10 GHz. Examples of suitable power include power in the range of 10 W to 10 kW. In some examples, the RF power source 534 is configured to operate at multiple different frequencies and / or powers.

[0109] The controller 550 is operably coupled to the substrate heater 508, the flow control hardware 514A - B, the remote plasma generator 530, the exhaust system 532, and the RF power supply 534. The controller 550 may further be operably coupled to any other suitable components of the processing tool 500. The controller 550 is configured to control various functions of the processing tool 500 and to deposit a hydrogen - contributing photosensitive lower layer including an EUV - absorbing photo - electron - emitting dopant bonded on the substrate 506. For example, the controller 550 is configured to operate the substrate heater 508 to heat the substrate. The controller 550 is also configured to operate the flow control hardware 514A to flow a selected gas or gas mixture at a selected flow rate into the processing chamber 502. The controller 550 is also configured to operate the exhaust system 532 to remove gas from the processing chamber 502. The controller 550 is further configured to operate the flow control hardware 514A - B and the exhaust system 532 to maintain a selected pressure within the processing chamber 502. Further, the controller 550 is configured to operate the remote plasma generator 530 and / or the RF power supply 534 to form a remote plasma including an inert gas and / or a hydrogen gas and to control any other functions of the processing tool 500. The controller 550 can comprise any suitable computing system, examples of which are described below with reference to FIG. 9.

[0110] For example, the controller 550 can operate the flow control hardware 514A to introduce dopant precursors and hydrocarbon precursors into the processing chamber 502, thereby exposing the substrate 506 to the precursor gases. The controller 550 can also operate the flow control hardware to introduce an inert gas and / or radical precursors into the remote plasma generator 530. The controller 550 can further operate the remote plasma generator 530 and / or the RF power supply 534 to form a plasma and introduce radical species into the processing chamber 502. Thus, the controller 550 can control the introduction of precursor gases and radical species into the processing chamber 502 such that the radical species react with one or more of the dopant precursors and hydrocarbon precursors to form a hydrogen-contributing photosensitive underlayer on the substrate 506.

[0111] In some examples, the introduction of the dopant precursor may be temporarily separated from the introduction of the radical species, alternatively or additionally. For example, the flow control hardware and the remote plasma generator can be configured to alternately expose the substrate to the radical species and the precursor gases.

[0112] FIG. 8 shows a flowchart illustrating an exemplary method 800 for forming a hydrogen-contributing photosensitive underlayer on a substrate. The processing tool 500 is an exemplary tool for implementing the method 800. The method 800 includes, at 802, exposing the substrate to dopant precursors and hydrocarbon precursors. The dopant precursors include EUV-absorbing photoemissive dopants bonded within carbon-containing polymerizable molecules. In some examples, at 804, the method includes introducing the dopant precursor downstream from an inlet ion shielding / radiation shielding structure. In examples where a plasma is used to form the radical species, 804 may help prevent cleavage of the bond between the EUV-absorbing photoemissive dopant and the carbon-containing polymerizable ligand in the example.

[0113] In some examples, the carbon-containing polymerizable molecule includes one or more of a carbon-carbon double bond, a carbon-carbon triple bond, or a cyclic group, as shown at 806. For example, the carbon-containing polymerizable molecule can include vinyl, ethynyl, allyl, propenyl, butenyl, and / or cyclopropyl ligands. As shown at 808, in some examples, the dopant precursor includes one or more of iodoethyne or 3-iodopropene. As shown at 810, in some examples, the dopant precursor includes one or more of dimethyltin(II), diethyltin(II), tetravinyltin(IV), or dimethyl(di vinyl)tin(IV).

[0114] At 812, in some examples, method 800 includes mixing the hydrocarbon precursor with hydrogen before exposing the substrate to the hydrocarbon precursor. At 814, in some examples, the method includes flowing a gas in which the ratio of the hydrocarbon precursor gas flow rate in sccm to the dopant precursor gas flow rate in sccm is in the range of 2:1 to 100:1.

[0115] Subsequently, at 816, method 800 further includes exposing the substrate to radical species formed by plasma. At 818, in some examples, the method includes introducing the radical species into a processing chamber comprising the substrate through an ion shielding / radiation shielding inlet. In such examples, the dopant precursor can be introduced downstream from the ion shielding / radiation shielding structure of the ion shielding / radiation shielding inlet, as shown at 804.

[0116] Subsequently, at 820, method 800 further includes forming a hydrogen-contributing photosensitive lower layer on the substrate from the dopant precursor and the hydrocarbon precursor by reaction of one or more of the dopant precursor and the hydrocarbon precursor with the radical species. At 822, in some examples, the method further includes controlling a substrate heater to heat to a temperature within the range of 100°C to 300°C.

[0117] Accordingly, the disclosed examples can provide a hydrogen-contributing photosensitive lower layer that includes a combined EUV-absorbing photoemissive dopant. When used in a patterning stack, the EUV-absorbing photoemissive dopant can absorb at least some EUV light that is not absorbed by the overlying photoresist layer. The EUV-absorbing photoemissive dopant can generate photoelectrons that assist in driving the crosslinking reaction in the photoresist and / or can generate additional labile hydrogen that promotes the crosslinking reaction in the photoresist. Since the EUV-absorbing photoemissive dopant is bonded to atoms in the hydrogen-contributing photosensitive lower layer, such a lower layer can reduce the risk of forming dopant hydrides from the labile hydrogen in the hydrogen-contributing photosensitive lower layer. Accordingly, the disclosed examples can help improve throughput by reducing the exposure time and / or dose of the EUV photoresist. For example, the disclosed examples can achieve dose vs size ≤ 50 mJ / cm 2 For the EUV photoresist. The disclosed examples may also help form features with well-defined features in the transition region. For example, the disclosed examples can be used to form features that include a pitch ≤ 36 nm. In some examples, features that include a linewidth roughness ≤ 3 nm can be formed when measured using post-development inspection (ADI). In some examples, features that include a local critical dimension uniformity ≤ 4 nm can be formed when measured using ADI. Additionally, the disclosed examples can provide an improvement of about 20% with respect to complex patterning (fidelity) compared to other examples that omit the use of an EUV-absorbing photoemissive dopant bonded to atoms in the hydrogen-contributing photoresist lower layer. Although disclosed with respect to EUV photoresist, the disclosed examples may also be used with any other suitable photoresist that includes a photoresist that absorbs a spectrum other than the EUV wavelength.

[0118] In some embodiments, the methods and processes described herein may be associated with a computing system of one or more computing devices. In particular, such methods and processes may be implemented as a computer application program or service, an application programming interface (API), a library, and / or other computer program products.

[0119] FIG. 9 schematically shows a non-limiting embodiment of a computing system 900 that can execute one or more of the methods and processes described above. Computing system 900 is shown in a simplified form. Computing system 900 may take the form of one or more personal computers, workstations, computers integrated with wafer processing tools, and / or network-accessible server computers.

[0120] Computing system 900 includes a logic machine 902 and a memory machine 904. Computing system 900 may optionally include a display subsystem 906, an input subsystem 908, a communication subsystem 910, and / or other components not shown in FIG. 9. Controller 550 is an example of a computing system 900.

[0121] Logic machine 902 includes one or more physical devices configured to execute instructions. For example, the logic machine may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical structures. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise reach a desired result.

[0122] A logic machine may include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. The processors of the logic machine may be single-core or multi-core, and the instructions executed therein may be configured for sequential, parallel, and / or distributed processing. The individual components of the logic machine may optionally be distributed among two or more separate devices, which may be remotely located and / or configured for coordinated processing. Aspects of the logic machine may be virtualized and executed by a remotely accessible network computing device configured in a cloud computing configuration.

[0123] The memory machine 904 includes one or more physical devices configured to hold instructions 912 executable by a logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of the memory machine 904 may be transformed, for example, to hold different data.

[0124] The memory machine 904 may include removable devices and / or built-in devices. The memory machine 904 can include, among other things, optical memory (e.g., CD, DVD, HD-DVD, Blu-ray disk, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic memory (e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.). The memory machine 904 may include volatile, non-volatile, dynamic, static, read / write, read-only, random access, sequential access, location-addressable, file-addressable, and / or content-addressable devices.

[0125] The memory machine 904 is understood to include one or more physical devices. However, aspects of the instructions described herein may instead be propagated by a communication medium (e.g., an electromagnetic signal, an optical signal, etc.) that is not held by a physical device for a finite period of time.

[0126] Aspects of the logic machine 902 and the memory machine 904 may be integrated into one or more hardware logic components. Such hardware logic components may include, for example, a field programmable gate array (FPGA), a program and application specific integrated circuit (PASIC / ASIC), a program and application specific standard product (PSSP / ASSP), a system on chip (SOC), and a complex programmable logic device (CPLD).

[0127] When included, the display subsystem 906 may be used to present a visual representation of data held by the memory machine 904. This visual representation may take the form of a graphical user interface (GUI). When the methods and processes described herein change data held by the memory machine, thereby transforming the state of the memory machine, the state of the display subsystem 906 may be similarly transformed to visually represent the underlying data change. The display subsystem 906 may include one or more display devices that utilize virtually any type of technology. Such display devices may be combined with the logic machine 902 and / or the memory machine 904 within a shared enclosure, or such display devices may be peripheral display devices.

[0128] When included, the input subsystem 908 can comprise or interface with one or more user input devices such as a keyboard, mouse, or touch screen. In some embodiments, the input subsystem can comprise or interface with a selected natural user input (NUI) component element. Such component elements can be integrated or peripheralized, and the conversion and / or processing of input actions can be handled on-board or off-board. Exemplary NUI component elements can include microphones for speech and / or voice recognition, as well as infrared, color, stereo, and / or depth cameras for machine vision and / or gesture recognition.

[0129] When included, the communication subsystem 910 can be configured to communicatively couple the computing system 900 with one or more other computing devices. The communication subsystem 910 can include wired and / or wireless communication devices compatible with one or more different communication protocols. By way of non-limiting example, the communication subsystem can be configured to communicate using a radio telephone network, or a wired or wireless local area network or wide area network. In some embodiments, the communication subsystem can enable the computing system 900 to send and / or receive messages with other devices over a network such as the Internet.

[0130] The configurations and / or techniques described herein are exemplary in nature and are subject to numerous modifications, and it will be understood that these specific embodiments or examples should not be considered in a limiting sense. The specific routines or methods described herein can represent one or more of any number of processing strategies. Accordingly, the various operations illustrated and / or described may be performed in other orders, in parallel, or omitted, in the order illustrated and / or described. Similarly, the order of the above-described processes may be changed.

[0131] 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, and any equivalents thereof.

Claims

1. A method of forming a photosensitive lower layer on a substrate, comprising: exposing the substrate to a dopant precursor and a hydrocarbon precursor, wherein the dopant precursor includes an extreme ultraviolet (EUV) absorbing photoemissive dopant bonded within a carbon-containing polymerizable molecule; exposing the substrate to radical species; and forming a hydrogen-contributing photosensitive lower layer on the substrate from the dopant precursor and the hydrocarbon precursor by reaction of the dopant precursor and the hydrocarbon precursor with the radical species. A method comprising the above steps.

2. The method according to claim 1, wherein exposing the substrate to the radical species includes introducing the radical species from a remote plasma through an ion shielding / radiation shielding inlet into a processing chamber comprising the substrate.

3. The method according to claim 2, wherein the dopant precursor is introduced downstream of an ion shielding / radiation shielding structure of the ion shielding / radiation shielding inlet.

4. The method according to claim 1, wherein the carbon-containing polymerizable molecule includes one or more of a carbon-carbon double bond, a carbon-carbon triple bond, or a cyclic group.

5. The method according to claim 1, further comprising mixing the hydrocarbon precursor with a hydrogen-containing gas before exposing the substrate to the hydrocarbon precursor.

6. The method according to claim 1, wherein the dopant precursor includes an iodine-containing dopant precursor.

7. The method according to claim 6, wherein the iodine-containing dopant precursor includes one or more of iodoethyne or 3-iodopropene.

8. The method according to claim 1, wherein the dopant precursor includes a tin-containing dopant precursor.

9. The method according to claim 8, wherein the tin-containing dopant precursor includes one or more of dimethyltin(II), diethyltin(II), tetravinyltin(IV), or dimethyl(di vinyl)tin(IV).

10. The method according to claim 1, wherein the ratio of the hydrocarbon precursor gas flow rate in standard cubic centimeters per minute (sccm) to the dopant precursor gas flow rate in sccm is in the range of 2:1 to 100:

1.

11. The method according to claim 1, wherein A method further comprising controlling a substrate heater to heat to a temperature within a range of 100°C to 300°C.

12. A patterning stack disposed on a substrate, a photoresist layer, a hydrogen-contributing photosensitive lower layer disposed between the photoresist layer and the substrate, the hydrogen-contributing photosensitive lower layer comprising a hydrogen-contributing photosensitive lower layer containing an extreme ultraviolet (EUV) absorbing photoemission dopant bonded to atoms in the hydrogen-contributing photosensitive lower layer and a patterning stack.

13. The patterning stack according to claim 12, wherein the hydrogen-contributing photosensitive lower layer contains silicon carbide, a patterning stack.

14. The patterning stack according to claim 12, wherein the hydrogen-contributing photosensitive lower layer contains a carbon-based polymer, a patterning stack.

15. The patterning stack according to claim 12, wherein the EUV absorbing photoemission dopant contains one or more of In, Sn, Sb, Te, or I, a patterning stack.

16. The patterning stack according to claim 12, wherein the photoresist layer contains an extreme ultraviolet (EUV) photoresist, a patterning stack.

17. The patterning stack according to claim 16, wherein the EUV photoresist contains a tin-based metal oxide photoresist, a patterning stack.

18. A processing tool, a processing chamber, a plasma generator, a high-frequency power source configured to provide high-frequency power to the plasma generator, flow rate control hardware configured to control the gas flow to the processing chamber and the plasma generator, a logic subsystem, the flow rate control hardware is controlled to introduce a dopant precursor and a hydrocarbon precursor into the processing chamber, the dopant precursor containing an extreme ultraviolet (EUV) absorbing photoemission dopant bonded within a carbon-containing polymerizable molecule, the flow rate control hardware is controlled to introduce an inert gas into the plasma generator, the high-frequency power source is controlled to form plasma in the plasma generator, the flow rate control hardware is controlled to introduce a radical species precursor into the plasma generator and a storage subsystem including instructions executable by the logic subsystem for a processing tool.

19. The processing tool according to claim 18, A processing tool further comprising a dopant precursor gas source, the dopant precursor gas source including one or more of an iodine-containing dopant or a tin-containing dopant.

20. The processing tool according to claim 18, The processing tool further comprising an ion shielding / radiation shielding inlet connecting the plasma generator and the processing chamber.

21. The processing tool according to claim 18, The command is executable to control the flow rate control hardware to flow the hydrocarbon precursor at a gas flow rate ratio within the range of 2 sccm:1 sccm to 10 sccm:1 sccm and to flow the dopant precursor.

22. The processing tool according to claim 18, The processing tool further comprising a substrate heater, the command being further executable to control the substrate heater to heat to a temperature within the range of 100°C to 300°C.

Images