Fabrication of EUV masks using combination of single layer lithography and regioselective deposition

Abstract

A surfactant or photoacid generator (PAG) forming a self-assembled monolayer is deposited on a substrate surface. Applying electron beam (e-beam) and / or extreme ultraviolet (EUV) radiation to the surface of the substrate forms a negative or positive pattern on the monolayer. Hydroxamic acid may be used to form a negative self-assembled monolayer, and silane or PAG may be used to form a positive self-assembled monolayer. The EUV absorbing material is selectively deposited in regions on the negative or positive patterned monolayer to form negative or positive EUV absorbing masks, respectively.

Description

Technical Field

[0001] The present invention generally relates to extreme ultraviolet (EUV) masks fabricated using a combination of monolayer lithography and area-selective deposition, and more particularly to EUV masks fabricated by lithographic patterning of a self-assembled monolayer on a substrate surface and area-selective deposition of an EUV absorbing material on the patterned monolayer. Background Art

[0002] High numerical aperture (NA) EUV lithography has two requirements for EUV absorbers: a contrast ratio of >85% and a thickness of <30 nm. Two examples of materials that meet the requirements of high NA EUV lithography are platinum (Pt) and tellurium (Te); however, these two materials are not suitable for conventional EUV patterning, which requires the generation of volatile species in order to pattern with etching; therefore, etch-resistant materials such as Pt and Te cannot be used for conventional EUV patterning. Currently, EUV mask manufacturing requires patterning via conventional deposition and etching with the absorber tantalum nitride (TaN). TaN has a contrast ratio of approximately 75% and a thickness of >60 nm; therefore, it does not meet the requirements of high NA EUV lithography. In order to achieve high NA EUV lithography, EUV mask manufacturing needs to evolve beyond currently used absorber materials and / or conventional techniques. Summary of the Invention

[0003] The present invention overcomes the need in the art by providing a method for EUV mask fabrication that does not require etching, thus allowing the application of etch-resistant getters that meet the requirements of high NA EUV lithography.

[0004] In one embodiment, the present invention is directed to a composition comprising: a substrate having a top surface and a bottom region; a self-assembled monolayer adhered to the top surface of the substrate, wherein the self-assembled monolayer comprises a surfactant or a photoacid generator; and an EUV absorbing film comprising at least one EUV absorbing material, wherein the EUV absorbing material is bound to the self-assembled monolayer in a negative or positive pattern.

[0005] In another embodiment, the present invention is directed to a method for making a positive EUV mask or a negative EUV mask, comprising: depositing a surfactant or a photoacid generator on a substrate, wherein the surfactant and / or the photoacid generator self-aligns on the surface of the substrate to form a monolayer; exposing the monolayer to a patterned e-beam or EUV radiation to form a resist pattern; and depositing an EUV absorbing material onto the monolayer, wherein the EUV absorbing material binds to unexposed areas of the monolayer to form a negatively patterned EUV mask or to exposed areas of the monolayer to form a positively patterned EUV mask.

[0006] In another embodiment, the present invention relates to a method for manufacturing a negative EUV mask, comprising: depositing an isohydroxamic acid comprising a polar head group and a non-polar tail on a substrate comprising a metal surface, wherein the isohydroxamic acid self-aligns to form a monolayer via reaction of the polar head group of the isohydroxamic acid with the metal surface of the substrate; exposing the monolayer to patterned e-beam or EUV radiation, wherein areas of the monolayer exposed to the e-beam or EUV radiation are cross-linked and areas not exposed to the e-beam or EUV radiation are uncross-linked; and depositing an EUV absorbing material onto the monolayer, wherein the EUV absorbing material bonds to the non-polar tail of the isohydroxamic acid on the unexposed and uncross-linked areas of the monolayer to form a negative EUV mask.

[0007] In another embodiment, the present invention is directed to a method for making a positive EUV mask comprising: depositing a silane on a substrate, wherein the silane has a reactive head group and a non-reactive tail, and the silane self-aligns via reaction of the head group with a top surface of the substrate to form a monolayer; treating the monolayer with patterned e-beam or EUV radiation, wherein the e-beam or EUV radiation activates the tails of the silane by creating polar groups on the tails of the silane only in areas of the monolayer exposed to the e-beam or EUV radiation; and depositing an EUV absorbing material onto the treated monolayer, wherein the EUV absorbing material binds to the polar groups of the silane tails to form a positive EUV mask.

[0008] In another embodiment, the present invention is directed to a method for manufacturing a positive EUV mask, comprising: depositing a photoacid generator (PAG) on a substrate, wherein the PAG has a reactive head group and a non-reactive tail group, and the PAG self-aligns via reaction of the head group with the top surface of the substrate to form a polymer brush monolayer; treating the PAG with patterned e-beam or EUV radiation, wherein the e-beam EUV radiation activates the tail groups of the PAG by generating polar acids on the tail groups of the PAG only in areas of the polymer brush monolayer exposed to the e-beam or EUV radiation; and depositing an EUV absorbing material onto the treated polymer brush monolayer, wherein the EUV absorbing material binds to the polar acids of the PAG tail groups to form a positive EUV mask.

[0009] In another embodiment, the substrate is a metal-capped substrate and the surfactant has 3-24 C atoms, a polar head group that chelates with the metal capping of the substrate, and a non-polar tail that binds to the EUV absorbing material in a negative pattern.

[0010] In a further embodiment, the metal surface of the substrate is selected from the group consisting of ruthenium, palladium, platinum, titanium, tantalum, nickel, copper, aluminum, and combinations thereof.

[0011] In another embodiment, the surfactant is an organosilicon compound having a reactive head that adheres to the substrate and a polar tail that binds to the EUV absorbing material in a positive pattern.

[0012] In further embodiments, the EUV absorbing material is selected from the group consisting of platinum, tellurium, zinc, titanium, antimony, indium, bismuth, silver, and combinations thereof.

[0013] In another embodiment, the self-assembled monolayer has cross-linked regions and non-cross-linked regions, wherein the EUV absorbing material adheres only to the non-cross-linked regions of the self-assembled monolayer in a negative pattern.

[0014] In another embodiment, the cross-linked regions of the monolayer are removed from the negative tone EUV mask using a reducing agent selected from the group consisting of H2 plasma, N2 plasma, NH3 plasma, and combinations thereof.

[0015] In another embodiment, the negative tone of the EUV mask is enhanced with a compound selected from the group consisting of phosphonic acid, phosphonic acid derivatives, stearic acid, stearic acid derivatives, and combinations thereof.

[0016] In another embodiment, the hydroxamic acid is selected from the group consisting of unsubstituted hydroxamic acid, methylhydroxamic acid, tetrahydroxamic acid, hexylhydroxamic acid, octylhydroxamic acid, cyclohexylhydroxamic acid, octadecylhydroxamic acid, dodecylhydroxamic acid, and combinations thereof.

[0017] In another embodiment, the hydroxamic acid further comprises a reactive group selected from the group consisting of olefins, alkynes, glycidyl groups, and combinations thereof.

[0018] In another embodiment, the silane is selected from the group consisting of aminosilanes, ethoxysilanes, chlorosilanes, glycidoxysilanes, methacryloxysilanes, methoxysilanes, N-alkyl-silanes, mercaptosilanes, and combinations thereof.

[0019] In another embodiment, the PAG is a polymer brush having a reactive head that adheres to the substrate and a polar tail that incorporates the EUV absorbing material in a positive pattern.

[0020] In another embodiment, the PAG is an ionic PAG selected from the group consisting of diaryliodonium salts, triarylsulfonium salts, and naphthalimide sulfonates, and combinations thereof.

[0021] In another embodiment, the PAG is a nonionic PAG selected from the group consisting of imidosulfonates, imidosulfonates, benzylsulfonates, and combinations thereof.

[0022] Additional aspects and / or embodiments of the present invention will be provided in the detailed description of the invention set forth below, but are not limited thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram illustrating the fabrication of a negative EUV mask.

[0024] Figure 2 is a schematic diagram illustrating the use of different surfaces for manufacturing negative EUV masks.

[0025] Figure 3 is a comparison graph of two negative zinc oxide (ZnO) EUV masks, one made with a self-assembled monolayer (SAM) of unsubstituted hydroxamic acid and the other made with a SAM of methylhydroxamic acid and ZnO.

[0026] Figure 4 is a graph showing the exposure results of atomic layer deposition (ALD) of the EUV absorber ZnO on two negative resists, one made with a SAM of unsubstituted hydroxamic acid and the other made with a SAM of methylhydroxamic acid.

[0027] Figure 5 is a graph showing the results of ALD exposure of ZnO on three negative resists, one made with a SAM of unsubstituted hydroxamic acid, another made with a SAM of methylhydroxamic acid and a third made with a SAM of cyclohexylhydroxamic acid.

[0028] Figure 6 The results show that the 0-205 mJ / cm applied to three ZnO negative EUV masks 2 Figure 3 Rutherford backscattering spectroscopy (RBS) contrast curves at EUV doses for a mask made with a SAM of unsubstituted hydroxamic acid, another with a SAM of methylhydroxamic acid, and a third with a SAM of cyclohexylhydroxamic acid.

[0029] Figure 7 The results show that the 1-205 mJ / cm applied to three ZnO negative EUV masks 2 X-ray photoelectron spectroscopy (XPS) contrast curves under EUV doses of 100 nm, one prepared with a SAM of cyclohexylhydroxamic acid, another with phosphonic acid and a third with octadecyl mercaptan (ODT).

[0030] Figure 8 Schematic diagram of the different packing densities of hydroxamic acid, methylhydroxamic acid, and cyclohexylhydroxamic acid.

[0031] Figure 9 Schematic illustration of how phosphonic acid increases the contrast of a hydroxamic acid SAM during regioselective deposition.

[0032] Figure 10 The fabrication of a positive tone EUV mask with a silane SAM on a substrate is schematically shown.

[0033] Figure 11 Figure 2 is a contrast graph of two positive-tone titanium dioxide (TiO2) masks, one made with 50 mol% trichlorophenylsilane (TPS) and the other made with 10 mol% TPS.

[0034] Figure 12A is a graph of a nonionic PAG, and Figure 12B is a diagram of a polymer incorporating a nonionic PAG.

[0035] Figures 13A-13C yes Figure 12B The SAM of non-ionic PAG was exposed to 193 nm before (pre-development) and after ( Figure 13A ), before and after exposure at 248 nm ( Figure 13B ) and after EUV exposure and development ( Figure 13C ) contrast curve. DETAILED DESCRIPTION

[0036] Set forth below is a description of what are presently considered to be preferred aspects and / or embodiments of the claimed invention. Any substitution or modification of function, purpose, or structure is intended to be covered by the appended claims. As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "comprise," "comprises," "includes," and / or "comprising" as used in the specification and the appended claims specify the presence of explicitly recited parts, elements, features, and / or steps, but do not preclude the presence or addition of one or more other parts, elements, features, and / or steps.

[0037] As used herein, the terms "photolithography" and "photoetching" refer to the creation of finely patterned thin films on a substrate to protect selected areas of the substrate during microchip fabrication.

[0038] As used herein, the term "EUV lithography" refers to lithography using light having a wavelength of 13.5 nm.

[0039] As used herein, the term "EUV radiation" refers to light having photons with energies in the range of 10 eV to 124 eV and wavelengths in the range of 10 nm to 100 nm.

[0040] As used herein, the term "electron-beam radiation" or "e-beam radiation" refers to the delivery of high-energy electrons to a material via an electron beam accelerator to induce changes in the material, such as cross-linking.

[0041] As used herein, the term "EUV mask" refers to a photolithographic film having (i) an EUV absorbing layer deposited atop multiple layers of EUV substrate material (e.g., 40-50 layers of molybdenum and silicon); (ii) a pattern defined on the EUV absorbing layer; and (iii) a surface that reflects light away from the patterned areas of the EUV absorbing layer. Because EUV masks are made of reflective surfaces and light-blocking elements that produce a pattern when exposed to ultraviolet radiation (which can be e-beam and / or EUV radiation), they differ from conventional photolithographic masks, which are opaque films or plates with holes or transparent areas that allow light to shine through in a defined pattern. EUV masks herein can be either negative-acting or positive-acting.

[0042] As used herein, the term "substrate" refers to the base material on which processing is performed.

[0043] As used herein, the terms "self-assembled monolayer" and "SAM" refer to a one-molecule-thick layer of material that is bound to a substrate surface in an ordered manner due to physical or chemical forces during a deposition process.

[0044] As used herein, the term "resist" refers to a layer applied to a substrate. In the context of the present invention, the term "resist" is used to denote a layer on a substrate that will ultimately be converted into an EUV mask when an EUV absorber is deposited on a self-assembled monolayer on the substrate.

[0045] As used herein, the term "ASD," which stands for "area selective deposition," refers to a bottom-up process that results in uniform deposition in selected areas of a patterned substrate. In the context of the present invention, area selective deposition is used to deposit an EUV absorber onto an EUV substrate having a surfactant monolayer on the top surface.

[0046] As used herein, the term "chemical vapor deposition" or "CVD" refers to a method that uses a vacuum to produce the area-selective deposition of thin films. With CVD, a substrate is exposed to one or more volatile precursors, which react and / or decompose on the substrate surface to deposit the material. Using CVD, volatile byproducts may be produced, which are typically removed by a gas flow through the reaction chamber. In the context of the present invention, CVD can be used for the area-selective deposition of EUV absorbers on EUV masks.

[0047] As used herein, the term "atomic layer deposition" or "ALD" refers to a method that uses a vapor phase chemical process to produce area selective deposition of thin films. ALD is considered a subclass of CVD. The ALD reaction uses two gaseous precursor chemicals that react with the substrate surface one at a time in a sequential, non-overlapping manner. In this way, the thin film is slowly deposited by repeated exposure to separate precursors. Unlike CVD, multiple ALD precursors are never present at the same time. In the context of the present invention, ALD can also be used for area selective deposition of EUV absorbers on EUV masks. In the context of the present invention, examples of materials that can be used for ALD include zinc oxide (ZnO), platinum (Pt), titanium dioxide (TiO2) or tellurium (Te).

[0048] An additive method for manufacturing high NA EUV masks by patterned growth of EUV absorbers on surfactant-treated substrates is described herein, wherein the surfactant is a patternable self-assembled monolayer at the substrate. The additive method enables the patterned addition of strong EUV absorbing films, such as Pt and / or Te films, which are difficult to pattern using conventional deposition and etching techniques. The EUV absorbing material can be deposited onto the surfactant-treated substrate by a regional selective deposition method of CVD or ALD without damaging the underlying substrate. The combination of the patternable surfactant monolayer and the regional selective deposition of the EUV absorber allows the manufacture of customized EUV masks. Because the additive method does not require an etching step, the additive method allows EUV masks to be manufactured with highly etch-resistant absorbers (such as Pt and / or Te). Therefore, the manufacture of the EUV mask described herein uses a combination of single-layer lithography and regional selective deposition, wherein the single-layer lithography patterns the surfactant self-assembled monolayer on the substrate surface and area, and the EUV mask is manufactured by selectively depositing the EUV absorber on the patterned surfactant monolayer.

[0049] In one embodiment, the high NA EUV absorber includes a chemical selected from platinum (Pt), tellurium (Te), zinc (Zn), titanium (Ti), antimony (SB), indium (In), bismuth (Bi), silver (Ag), and combinations thereof.

[0050] In another embodiment, the surfactant for forming a self-assembled monolayer has 3-42 carbon atoms. In another embodiment, the surfactant has a polar head group and a non-polar tail group. In another embodiment, the surfactant has a reactive side group that helps the surfactant to self-assemble into a monolayer. Such reactive side groups include but are not limited to olefins, alkynes, glycidyl groups and combinations thereof. Examples of surfactants that can be used to form a self-assembled monolayer include but are not limited to hydroxamic acid and its derivatives (collectively referred to herein as "hydroxamic acid"), silanes and their derivatives (referred to herein as "silanes") and photoacid generators (PAGs).

[0051] Hydroxamic acids are a class of organic compounds having the formula RC(O)N(OH)R', where CO is a carbonyl group, R is an organic residue, and R' is. Hydroxamic acids typically consist of a polar hydroxamic head group, a hydrophobic methylene spacer, a second polar site, and a terminal non-polar hydrophobic group. In the context of the present invention, the polar head of the hydroxamic acid strongly binds to metal ions on the surface of the substrate material to form a self-assembled monolayer. Upon exposure to e-beam and / or E-UV radiation, the iron-chelating polar head of the hydroxamic acid crosslinks. EUV absorbers are covalently bound to the non-polar tail of the hydroxamic acid during ALD or CVD. The hydroxamic acids useful in the self-assembled monolayers described herein may be substituted or unsubstituted. Examples of hydroxamic acids include, but are not limited to, unsubstituted hydroxamic acid, methyl hydroxamic acid, n-butyl hydroxamic acid, n-hexyl hydroxamic acid, n-octyl hydroxamic acid, cyclohexyl hydroxamic acid, octadecyl hydroxamic acid, dodecyl hydroxamic acid, and combinations thereof. Example 1 describes a negative tone EUV mask fabricated using a hydroxamic acid self-assembled monolayer.

[0052] Silane is a class of silanes with the formula Si n R 2n+2 A charge-neutral silicon compound wherein n=1, 2, 3, 4, etc., and the R substituent can be a combination of organic or inorganic groups. Most silanes are organosilicon compounds containing Si-C bonds. Silanes used as self-assembled monolayers are typically composed of a reactive head group comprising silicon and a non-reactive tail. In the context of the present invention, the reactive head of the silane is bound to any suitable substrate surface to form a self-assembled monolayer. When exposed to oxygen after exposure to e-beam and / or EUV radiation, the non-reactive tail of the silane becomes reactive and chemically bonds to oxygen, converting the silane tail into a reactive polar group comprising at least one hydroxyl (-OH) and / or carbonyl (-COOH) group. Examples of silanes that can be used for the self-assembled monolayer described herein include, but are not limited to, aminosilanes, ethoxysilanes, chlorosilanes, glycidyloxysilanes, methacryloxysilanes, methoxysilanes, N-alkyl-silanes, mercaptosilanes, and combinations thereof. Example 2 describes a positive EUV mask made with a silane self-assembled monolayer.

[0053] PAG decomposes and produces protons (H + ) (i.e., an organic compound that produces a polar acid). PAGs are divided into two groups: ionic PAGs and non-ionic PAGs. Examples of ionic PAGs include, but are not limited to, diaryliodonium salts, triarylsulfonium salts, and naphthalimide sulfonates, and combinations thereof. Examples of non-ionic PAGs include, but are not limited to, iminosulfonates, imidosulfonates, benzylsulfonates, and combinations thereof. Example 3 describes a positive EUV mask fabricated using a silane self-assembled monolayer.

[0054] In one embodiment, the EUV mask has a negative tone, hydroxamic acid is used for the self-assembled monolayer, and e-beam and / or EUV radiation is used for patterning. Pattern formation occurs via patterned e-beam and / or EUV radiation, wherein exposed regions of the surfactant-treated SAM are crosslinked, while unexposed regions are not crosslinked. When an EUV absorber is deposited onto the treated and irradiated SAM, the EUV absorber grows only on regions of the treated SAM that have not been exposed to e-beam and / or EUV radiation.

[0055] In another embodiment, the hydroxamic acid monolayer is treated or replaced with a contrast enhancing agent after e-beam and / or EUV exposure and before deposition of the EUV absorbing material. Examples of contrast enhancing materials that can be applied to the surfactant monolayer include, but are not limited to, phosphonic acid, phosphonic acid derivatives, stearic acid, stearic acid derivatives, and combinations thereof.

[0056] In another embodiment, the cross-linked regions of the hydroxamic acid monolayer are removed from the EUV mask substrate using a reducing agent selected from the group consisting of H2 plasma, N2 plasma, NH3 plasma, and combinations thereof.

[0057] In another embodiment, the substrate for the negative EUV mask is coated with a metal selected from the group consisting of ruthenium, palladium, platinum, titanium, tantalum, nickel, copper, aluminum, and combinations thereof. In another embodiment, the substrate for the negative EUV mask comprises silicon, silicon dioxide, beryllium, molybdenum, and combinations thereof. In another embodiment, the substrate is a multilayer film comprising silicon, silicon dioxide, beryllium, molybdenum, and combinations thereof. In another embodiment, the substrate is a multilayer film comprising molybdenum silicon (Mo / Si) or molybdenum beryllium (Mo / Be). In another embodiment, the substrate is planar. In another embodiment, the substrates are coplanar.

[0058] Figure 1 Schematic diagram showing the fabrication of a negative EUV mask using a hydroxamic acid monolayer on a Ru-covered Mo / Si multilayer substrate, patterned cross-linking of the hydroxamic acid monolayer using e-beam, atomic layer deposition of negative high-NA EUV absorbers Pt or Te, and removal of the cross-linked areas of the negative EUV mask via H2 plasma.

[0059] Figure 2 Schematic illustration of how the negative resists described herein can be tailored based on the planar configuration of the substrate surface. Figure 1 The negative process shown in produces a barrier-type negative pattern (above), while applying a negative process on a coplanar surface produces a grid-type negative pattern.

[0060] Figure 3Figure 1 shows the resist contrast curves of two negative EUV masks prepared using Rutherford Backscattering Spectroscopy (RBS). Both negative EUV masks were prepared using the EUV absorber zinc oxide (ZnO). One resist was made using a SAM of unsubstituted hydroxamic acid and 600 ALD cycles of ZnO, while the other was made using a SAM of methyl hydroxamic acid and 300 ALD cycles of ZnO. Both resists were exposed to EUV doses ranging from 0 to 205 mJ. The resist made with unsubstituted hydroxamic acid was exposed to EUV doses of 205 mJ / cm 2 EUV doses seen under mask exposure (<0 mJ / cm 2 EUV) and unexposed (0 mJ / cm 2 The maximum contrast between EUV regions. The resist made with methyl hydroxamic acid at 70 mJ / cm 2 The maximum contrast is seen between the exposed and unexposed areas of the mask in the EUV range, which is achieved with 205 mJ / cm 2 The exposure dose remains constant.

[0061] Figure 4 The results show that the etchant temperature of the two negative resists is 205 mJ / cm 2 Figure 1 shows the results of atomic layer deposition of a constant dose of EUV absorber zinc oxide (ZnO), one resist made with a SAM of unsubstituted hydroxamic acid and the other with a SAM of methylhydroxamic acid. The growth rate of ZnO over 600 ALD cycles is shown for the exposed and unexposed areas of each resist. The thickness of ZnO grew from 0-40 nm on the unexposed (i.e., uncrosslinked) areas of the negative resist made with methylhydroxamic acid, and from 0-15 nm on the unexposed areas of the negative resist made with unsubstituted hydroxamic acid. In both resists, ZnO did not grow on the exposed (i.e., crosslinked) areas of the SAM.

[0062] Figure 5 is a graph showing the results of atomic layer deposition of ZnO on three negative patterned resists, one made with a SAM of unsubstituted hydroxamic acid and not exposed to EUV radiation, and the other made with a SAM of methylhydroxamic acid and exposed to EUV radiation at 205 mJ / cm 2 The third was made with a SAM of cyclohexylhydroxamic acid and exposed to EUV at 205 mJ / cm 2 The unsubstituted hydroxamic acid SAM that was not exposed to EUV radiation showed no growth after 500 ALD cycles, while the exposed methyl hydroxamic acid showed ZnO growth to 27 nm after 400 ALD cycles, and the exposed cyclohexyl hydroxamic acid showed ZnO growth to 14.6 nm after 400 ALD cycles.

[0063] Figure 6 Figure 1 is a resist contrast curve prepared using RBS on three ZnO negative resists, one made with a SAM of unsubstituted hydroxamic acid, another made with a SAM of methylhydroxamic acid and a third made with a SAM of cyclohexylhydroxamic acid, all exposed to EUV doses ranging from 0-200 mJ. RBS was used to measure the ZnO thickness (in nm) at different EUV doses. The resist made with the unsubstituted hydroxamic acid SAM was exposed to EUV doses of 205 mJ / cm 2 The maximum contrast between the exposed and unexposed areas of the mask is seen at an EUV dose of 70 mJ / cm 2 The maximum contrast is seen between the exposed and unexposed areas of the mask in the EUV range, which is achieved with 205 mJ / cm 2 The exposure dose was kept constant. The resist made with cyclohexylhydroxamic acid SAM saw the maximum contrast between the exposed and unexposed areas of the mask at EUV range of 65, which was achieved by 205 mJ / cm 2 The exposure remains relatively constant. The comparison curves of unsubstituted hydroxamic acid SAM and methyl hydroxamic acid SAM are similar to Figure 3 Those in the same.

[0064] Figure 7 Resist contrast curves prepared using x-ray photoelectron spectroscopy (XPS) on three negative tone resists fabricated, one with a SAM of cyclohexylhydroxamic acid, another with a monolayer of phosphonic acid, and a third with a monolayer of octadecyl mercaptan (ODT), all exposed to 0–205 mJ / cm 2 The range of EUV doses. XPS was used to measure the percentage of ZN at different EUV doses. The resist made with cyclohexyl hydroxamic acid SAM was exposed to 205 mJ / cm 2 The maximum contrast is seen between the exposed and unexposed areas of the mask at 100 nm. Resists made with phosphonic acid show no adhesion of ZnO to the phosphonic acid, and therefore cannot be used to produce EUV masks. Resists made with ODT show ZnO adhesion to the ODT, but do not show any meaningful change in ZnO percentage at any EUV dose. Figure 7 It was shown that, unlike phosphonic acid and ODT, the hydroxamic acid SAMs described herein produce functional EUV masks.

[0065] Figure 8 Schematic diagram of the different packing densities of hydroxamic acid, methylhydroxamic acid, and cyclohexylhydroxamic acid.

[0066] Figure 9Schematic illustration of how phosphonic acid increases the contrast of a hydroxamic acid self-assembled monolayer during area-selective deposition. The phosphonic acid displaces uncrosslinked hydroxamic acid from the surface of the SAM in the unexposed, crosslinked regions of the SAM, thereby increasing the contrast between the unexposed and exposed regions of the SAM during ASD.

[0067] In another embodiment, the EUV mask has a positive tone, silane is used for the self-assembled monolayer, and e-beam and / or EUV radiation (collectively referred to as "exposure") is used for patterning. Because the tails of the non-reactive silane molecules are rendered reactive by generating polar groups upon exposure, patterned exposure of the silane SAM causes the exposed areas to become reactive while the non-exposed areas remain non-reactive. When the EUV absorber is deposited onto the irradiated and / or phototreated SAM, the EUV absorber grows only on the areas of the SAM that have been exposed. Any suitable substrate can be used to create a positive tone EUV mask with silane; examples of substrate materials include, but are not limited to, silicon, silicon dioxide, ruthenium, molybdenum, and combinations thereof.

[0068] Figure 10 Schematic illustration of the fabrication of a positive EUV mask with a silane monolayer on a substrate, e-beam patterning of the monolayer to activate the non-reactive tail of the silane by polar group generation, and atomic layer deposition of positive high NA EUV absorbers Pt or Te.

[0069] Figure 11 Figure 1 shows the resist contrast curves of two positive tone EUV masks made with the EUV absorber titanium dioxide (TiO2). One was made with a SAM of 50 mol% trichloro(octadecyl)silane and 50 mol% trichlorophenylsilane (TPS) and the other was made with a SAM of 90 mol% trichloro(octadecyl)silane and 10 mol% TPS. Both resists were exposed to 0-280 mJ / cm 2 EUV dose range. Two positive resists at 280 mJ / cm 2 EUV doses seen under mask exposure (<0 mJ / cm 2 EUV) and unexposed (0 mJ / cm 2 The maximum contrast between EUV (EUV) regions is shown, where the 50 mol% TPS resist has slightly thicker TiO2 thickness (~0.1 nm to 0.3 nm greater thickness) at each EUV dose compared to the 10 mol% TPS resist.

[0070] In another embodiment, the EUV mask has a positive tone, PAG is used for self-assembly monolayer, and e-beam and / or EUV radiation is used for patterning. PAG self-assembles into a polymer brush monolayer on the substrate surface. The polymer brush comprises long chain molecules that are tethered to the assembly, which are attached to the substrate at one end and extend away from the substrate at the other end. As block polymers, the polymer brushes behave differently from free polymer chains. Upon exposure to e-beam and / or EUV radiation, the non-reactive tails of the PAG polymer brushes are converted to polar acids. Any suitable substrate can be used to produce a positive tone EUV mask with PAG. Examples of substrate materials for positive tone masks include, but are not limited to, silicon, silicon dioxide, ruthenium, molybdenum, and combinations thereof.

[0071] Figure 12A is a graph of a nonionic PAG, and Figure 12B is incorporated Figure 12A Diagram of a PAG polyacrylate polymer.

[0072] Figures 13A-13C It is used Figure 12B The resist made of non-ionic PAG polymer before and after exposure at 193 nm ( Figure 13A ), before and after 248 nm exposure ( Figure 13B ) and after EUV exposure and development ( Figure 13C ). After exposure at 248 nm, the thickness of the PAG SAM was between 400-450 mJ / cm 2 The dose range is from 575 to 0Å; after exposure at 193 nm, the thickness of PAG SAM is 35 mJ / cm 2 The dose was reduced from 625 to 0Å; and after EUV exposure and development, the thickness of PAG SAM was 3-5 mJ / cm 2 The dose range is from 385 to 1 Å. The results show that the sensitivity of non-ionic PAG increases with EUV exposure relative to 248 and 193 Å exposure.

[0073] The description of various aspects and / or embodiments of the present invention has been presented for illustrative purposes, but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the aspects and / or embodiments, practical applications, or technical improvements over technologies found in the marketplace, or to enable those of ordinary skill in the art to understand the aspects and / or embodiments disclosed herein.

[0074] Experimental part

[0075] The following examples are set forth to provide a complete disclosure of how to prepare and use aspects and embodiments of the present invention as described herein to those of ordinary skill in the art. Although efforts have been made to ensure accuracy with respect to variables (e.g., amounts, temperatures, etc.), experimental errors and deviations should be considered. Unless otherwise stated, parts are by weight, temperatures are degrees Celsius, and pressures are at or near atmospheric pressure. Unless otherwise stated, all components are commercially available.

[0076] Example 1

[0077] Negative EUV mask fabricated using hydroxamic acid self-assembled monolayers

[0078] The ruthenium (Ru) terminated molybdenum-silicon (Mo / Si) multilayer structure is immersed in the 4-methyl-2-pentanol solution of about 0.1 wt% hydroxamic acid and is no more than 30 minutes.Then rinse the surface with 4-methyl-2-pentanol and dry under N2.In order to produce negative EUV mask, the surface of the monolayer coating is then subjected to patterned e-beam radiation (EUV radiation can also be used for this step), which makes the hydroxamic acid crosslinked only in the region exposed to e-beam radiation.Then in atomic layer deposition process, the patterned monolayer is subjected to the ZnO produced by the semi-circulation of diethylzinc and water, wherein the film only grows in the uncrosslinked region, and does not grow on the crosslinked region of the monolayer, leaving negative EUV mask (Pt, TiO2 or Te atomic layer deposition can also be used for this step-).After atomic layer deposition, by H2 plasma removes residual crosslinked self-assembled monolayer.

[0079] Example 2

[0080] Positive EUV mask fabricated using silane self-assembled monolayers

[0081] The ruthenium (Ru) terminated molybdenum-silicon (Mo / Si) multilayer structure is immersed in a toluene solution (1 wt % solution) of octadecyltriethoxysilane for about 30 minutes, at which time reactive silane reacts with the substrate surface to form a self-assembled monolayer. The substrate surface with the bonded silane is then rinsed with toluene, then rinsed with 4-methyl-2-pentanol, and dried under N2. In order to produce a positive EUV mask, the surface of the monolayer coating undergoes patterned e-beam or EUV radiation, which is then exposed to ambient air, wherein the combination of radiation and oxygen exposure activates the non-reactive tail of the silane to produce a reactive polar group with at least one-OH and / or COOH group. The patterned monolayer is then subjected to ZnO, Pt, TiO2 or Te atomic layer deposition, wherein the film grows on the reactive polar group, thereby leaving a positive EUV mask. After atomic layer deposition, any residual aminosilane that is not bonded to the substrate or not activated by radiation is removed via H2 plasma.

[0082] Example 3

[0083] Positive EUV mask fabricated using self-assembled monolayers of photoacid generators

[0084] The ruthenium (Ru)-terminated molybdenum-silicon (Mo / Si) multilayer structure was immersed in a solution of an ionic PAG (1,8-naphthylamide sulfonate) for approximately 30 minutes, at which point the ionic PAG bound to the substrate surface. The substrate surface with the bound ionic PAG was then rinsed with 4-methyl-2-pentanol and dried under N2. To create a positive EUV mask, the monolayer coated surface was subjected to patterned e-beam or EUV radiation, which generated reactive H on the monolayer surface. + Polar acid groups. The patterned monolayer is then subjected to atomic layer deposition of ZnO, Pt, TiO2, or Te, where a film grows on the reactive polar acid groups, leaving behind a positive EUV mask. After atomic layer deposition, any residual PAG that is not bound to the substrate or activated by irradiation is removed via H2 plasma.

Claims

1. A composition comprising: a substrate having a top surface and a bottom region; a self-assembled monolayer adhered to a top surface of the substrate, wherein the self-assembled monolayer comprises a surfactant or a photoacid generator; and An extreme ultraviolet (EUV) absorbing film comprising at least one EUV absorbing material, wherein the EUV absorbing material is bound to a self-assembled monolayer in a negative or positive pattern.

2. The composition of claim 1 , wherein the substrate is a metal-capped substrate and the surfactant has 3 to 24 C atoms, a polar head group that chelates with the metal capping of the substrate, and a non-polar tail that binds to the EUV absorbing material in a negative pattern.

3. The composition according to claim 1, wherein the self-assembled monolayer has cross-linked regions and non-cross-linked regions, wherein the EUV absorbing material adheres only to the non-cross-linked regions of the self-assembled monolayer in a negative pattern.

4. The composition of claim 1, wherein the surfactant is an organosilicon compound having a reactive head portion that adheres to the substrate and a polar tail portion that binds to the EUV absorbing material in a positive pattern.

5. The composition of claim 1, wherein the photoacid generator is a polymer brush having a reactive head that adheres to the substrate and a polar tail that binds the EUV absorbing material in a positive pattern.

6. The composition of claim 1, wherein the EUV absorbing material is selected from the group consisting of platinum, tellurium, zinc, titanium, antimony, indium, bismuth, silver, and combinations thereof.

7. A method for manufacturing a positive extreme ultraviolet (EUV) mask or a negative extreme ultraviolet (EUV) mask, comprising: depositing a surfactant or a photoacid generator on a substrate, wherein the surfactant and / or the photoacid generator self-aligns on the surface of the substrate to form a monolayer; exposing the monolayer to a patterned electron beam or EUV radiation to form a resist pattern; and An EUV absorbing material is deposited onto the monolayer, wherein the EUV absorbing material bonds to unexposed areas of the monolayer to form a negatively patterned EUV mask or to exposed areas of the monolayer to form a positively patterned EUV mask.

8. The method of claim 7, wherein the substrate is a metal-capped substrate and the surfactant has 3 to 24 C atoms, a polar head group that chelates with the metal capping of the substrate, and a non-polar tail that binds to the EUV absorbing material in a negative pattern.

9. The method according to claim 7, wherein the self-assembled monolayer has cross-linked regions and non-cross-linked regions, wherein the EUV absorbing material is bound only to the non-cross-linked regions of the self-assembled monolayer in a negative pattern.

10. The method of claim 7, wherein the surfactant is an organosilicon compound having a reactive head portion that adheres to the substrate and a polar tail portion that binds the EUV absorbing material in a positive pattern.

11. The method of claim 7, wherein the photoacid generator is a polymer brush having a reactive head that adheres to the substrate and a polar tail that binds the EUV absorbing material in a positive pattern.

12. The method of claim 7, wherein the EUV absorbing material is selected from the group consisting of platinum, tellurium, zinc, titanium, antimony, indium, bismuth, silver, and combinations thereof.

13. A method for manufacturing a negative-tone extreme ultraviolet (EUV) mask, comprising: depositing a hydroxamic acid comprising a polar head group and a non-polar tail on a substrate comprising a metal surface, wherein the hydroxamic acid self-aligns via reaction of the polar head group of the hydroxamic acid with the metal surface of the substrate to form a monolayer; exposing the monolayer to patterned electron beam (e-beam) or EUV radiation, wherein regions of the monolayer exposed to the e-beam or EUV radiation are crosslinked and regions not exposed to the e-beam or EUV radiation are not crosslinked; and An EUV absorbing material is deposited onto the monolayer, wherein the EUV absorbing material binds to the non-polar tails of the hydroxamic acid on unexposed and uncrosslinked regions of the monolayer to form a negative tone EUV mask.

14. The method of claim 13, wherein the metal surface of the substrate is selected from the group consisting of ruthenium, palladium, platinum, titanium, tantalum, nickel, copper, aluminum, and combinations thereof.

15. The method of claim 13, wherein the hydroxamic acid is selected from the group consisting of unsubstituted hydroxamic acid, methylhydroxamic acid, tetrahydroxamic acid, hexylhydroxamic acid, octylhydroxamic acid, cyclohexylhydroxamic acid, octadecylhydroxamic acid, dodecylhydroxamic acid, and combinations thereof.

16. The method of claim 13, wherein the hydroxamic acid further comprises a reactive group selected from the group consisting of olefins, alkynes, glycidyl groups, and combinations thereof.

17. The method of claim 13, wherein the cross-linked regions of the monolayer are removed from the negative tone EUV mask using a reducing agent selected from the group consisting of H2 plasma, N2 plasma, NH3 plasma, and combinations thereof.

18. The method according to claim 13, wherein the negative tone of the EUV mask is enhanced with a compound selected from the group consisting of phosphonic acid, phosphonic acid derivatives, stearic acid, stearic acid derivatives, and combinations thereof.

19. The method of claim 13, wherein the EUV absorbing material is selected from the group consisting of platinum, tellurium, zinc, titanium, antimony, indium, bismuth, silver, and combinations thereof.

20. A method for manufacturing a positive extreme ultraviolet (EUV) mask, comprising: depositing silane on the substrate, wherein the silane has a reactive head group and a non-reactive tail, and the silane self-aligns via reaction of the head group with a top surface of the substrate to form a monolayer; treating the monolayer with patterned e-beam or EUV radiation, wherein the e-beam or EUV radiation activates the silane tails by creating polar groups on the silane tails only in the areas of the monolayer exposed to the e-beam or EUV radiation; and An EUV absorbing material is deposited onto the treated monolayer, wherein the EUV absorbing material is bonded to the polar groups of the silane tails to form a positive tone EUV mask.

21. The method of claim 20, wherein the silane is selected from the group consisting of aminosilanes, ethoxysilanes, chlorosilanes, glycidoxysilanes, methacryloxysilanes, methoxysilanes, N-alkylsilanes, mercaptosilanes, and combinations thereof.

22. A method for manufacturing a positive extreme ultraviolet (EUV) mask, comprising: depositing a photoacid generator (PAG) on a substrate, wherein the PAG has a reactive head group and a non-reactive tail group, and the PAG self-aligns via reaction of the head group with a top surface of the substrate to form a polymer brush monolayer; treating the PAG with patterned EUV radiation, wherein the EUV radiation activates the tail groups of the PAG by generating polar acids on the tail groups of the PAG only in regions of the polymer brush monolayer exposed to the EUV radiation; and An EUV absorbing material is deposited onto the treated polymer brush monolayer, wherein the EUV absorbing material is bound to the polar acid of the PAG tail group to form a positive tone EUV mask.

23. The method according to claim 22, wherein the PAG is an ionic PAG selected from the group consisting of diaryliodonium salts, triarylsulfonium salts, and naphthalimide sulfonates, and combinations thereof.

24. The method of claim 22, wherein the PAG is a nonionic PAG selected from the group consisting of imidosulfonates, amidosulfonates, benzylsulfonates, and combinations thereof.

25. The method of claim 22, wherein the EUV absorbing material is selected from the group consisting of platinum, tellurium, zinc, titanium, antimony, indium, bismuth, silver, and combinations thereof.

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