KR20180054509A - Sensitivity-enhanced photoresist - Google Patents

Abstract

The present disclosure relates to novel positive and negative photoresist compositions containing components based on one or more specific metals, metal salts and / or metal complexes and methods of use thereof. The photoresist compositions and methods can be used to produce high speed fine pattern processing using ultraviolet, extreme ultraviolet, beyond extreme ultraviolet radiation, x-rays, electron beams, and other charged particle rays . The metal is characterized by a high absorption cross-section and a selected elastic and inelastic electronic cross-section.

Description

Sensitivity-enhanced photoresist

The present invention relates to novel positive and negative photoresist compositions containing certain metal-based components and methods of using them. The photoresist compositions and methods are ideal for high-speed, fine pattern processing using, for example, ultraviolet, extreme ultraviolet, ultraviolet, X-rays, electron beams and other charged particle rays.

preceding Reference to the application

This application is a continuation-in-part of U.S. Provisional Patent Application No. 62 / 1651,364 entitled " Sensitivity Enhanced Photoresist ", filed April 22, 2015, which is incorporated herein by reference in its entirety. 119 (e).

As is well known, the fabrication process for various types of electronic or semiconductor devices, such as ICs, LSIs, and the like, requires fine patterning of the resist layer on the surface of a substrate material, such as a semiconductor silicon wafer, ). This fine patterning process has traditionally been performed by a photolithographic method in which the substrate surface is uniformly coated with a positive or negative tone photoresist composition to form a thin layer of the photoresist composition and is exposed to actinic radiation actinic rays (e.g., ultraviolet light) and then developed to selectively dissolve the photoresist layer in the region of the positive resist exposed to actinic radiation or in the region of the negative resist not exposed to actinic radiation , Leaving a patterned resist layer on the substrate surface. The patterned resist layer thus obtained can be used as a mask in subsequent processing on the substrate surface, such as etching, plating, self-assembly processes, and the like. The fabrication of structures with dimensions on the order of nanometers is a significant area of interest because it enables the realization of electronic and optical devices and also exploits new phenomena such as quantum confinement effects, Because it enables component packing density. As a result, the resist layer is constantly required to have fineness that can be achieved by methods such as using actinic radiation having a shorter wavelength than conventional ultraviolet light. Therefore, in the present case, an electron beam (e-beam), an excimer laser beam, EUV, BEUV and X-ray are used as short-wavelength actinic rays instead of conventional ultraviolet rays. The minimum size that can be obtained is mainly determined by the performance of the resist material and the wavelength of the actinic radiation. Various materials have been proposed as resist materials suitable for obtaining such a fine pattern. In the case of negative tone resists based on polymer crosslinks, there is an inherent resolution limit of about 10 nm, which is the approximate radius of a single polymer molecule.

It is also known to apply a technique called "chemical amplification" to a polymeric resist material. Chemically amplified resist materials are generally multi-component formulations, including polymeric main components such as novolac resin, which contribute to properties such as resistance and mechanical stability of the material for etching, and resist and photogenerators, Lt; RTI ID = 0.0 > a < / RTI > desired property. By definition, chemical amplification occurs through a catalytic process involving a photosensitizer, resulting in a single irradiation phenomenon that causes exposure of a large number of resist molecules. In a typical embodiment, the resist comprises a polymer and a photoacid generator (PAG) as a photosensitizer. A PAG emits a proton, either directly or through a process mediated by other components in the resist, when a radiation (light or electron beam) is present. In such processes, for example, in processes such as EUV and Ebeam exposures where the photons / electrons typically interact with the polymer or crosslinker, they interact with the PAG to produce radicals that form protons.

This proton may then react with, for example, a polymer to lose functional groups or cause cross-linking. In this process, a second proton capable of reacting with additional molecules is produced. The rate of the reaction can be controlled, for example, by heating the resist film to allow the reaction to proceed. After heating, the reacted polymer molecules react freely with the remaining components of the formulation, which will be suitable for negative tone resists. In this way, the sensitivity to the actinic radiation of the material is significantly increased since a small number of the irradiation events cause a large number of exposure events.

In such a chemical amplification scheme, irradiation results in cross-linking of the exposed resist material to produce a negative tone resist. The polymeric resist material may be self crosslinking or may comprise crosslinking molecules. Chemical amplification of polymer-based resists is described in U.S. Patent Nos. 5,968,712, 5,529,885, 5,981,139 and 6,607,870.

Various fullerene derivatives have been found to be electron beam resist materials useful by the inventors (Appl. Phys. Lett., Volume 72, page 1302 (1998), Appl. Phys. Lett., Volume 312, page 469 Res. Soc. Symp., Proc., Volume 546, page 219 (1999), and U.S. Patent No. 6,117,617).

In addition, the photogenerated acid material can be used to interact with selected materials that may have acid labile groups as components, wherein the remainder of the material is a developer, for example, a base containing developer base containing developer. The area of interest at all times is the photospeed of the photoresist. Higher photo speeds represent higher throughput, and in some cases higher photo speeds may mean improved resolution. Various methods and "tricks" have been used to increase the photo speed of both positive and negative actuated photoresists, including the addition of photocatalysts, photosensitizers and light absorbents.

As can be seen, there is a continuing need to obtain even finer resolution photoresists that will enable the production of smaller and smaller semiconductor devices to meet current and future requirements. It would also be desirable to produce materials that can be used with such photoresists, which would be more robust to the process used to fabricate current semiconductor devices, such as, for example, etch resistance. There is also a continuing need to increase the photo speed of lithographic photoresists.

A first embodiment disclosed and claimed herein is a photoresist composition comprising at least one metal component, wherein the metal component has a high EUV light absorption cross-section, median to high inelastic electron scattering and low to medium (Low to median) elastic scattering coefficient.

A second embodiment disclosed and claimed herein is a photoresist composition of this embodiment, wherein at least one metal is selected from the group consisting of elements 3 to 17 and elements 3 to 6 of the Periodic Table of Elements (such as scandium, titanium, vanadium, A metal such as chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, bromine, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, And metals belonging to Group 13 to Group 17 and three cycles (including aluminum, silicon (including aluminum), silicon (silicon), silicon , Phosphorus, sulfur and chlorine.

A third embodiment disclosed and claimed herein is a photoresist composition of this embodiment, wherein said at least one metal comprises a metal salt, a coordinated complex and / or a metal containing ligand.

A fourth embodiment disclosed and claimed herein is a photoresist composition of this embodiment, wherein said at least one metal salt comprises an oligomeric or polymeric ligand.

A fifth embodiment disclosed and claimed herein is a photoresist of this embodiment, wherein the photoresist composition comprises a negative working photoresist or a positive working photoresist and has sensitivity to irradiation including EUV irradiation, or And has sensitivity to electron beam irradiation.

A sixth embodiment disclosed and claimed herein is a photoresist of this embodiment, wherein said at least one metal complex comprises at least one EUV stable complexing material or at least one EUV-unstable complexing material.

A seventh embodiment disclosed and claimed herein is a photoresist composition of this embodiment comprising a photoacid generator.

An eighth embodiment disclosed and claimed herein is a photoresist composition of the above embodiment, wherein the composition comprises at least one of malonate, malonate-imine adduct or malonate-amine-imide adduct.

A ninth embodiment disclosed and claimed herein is directed to a composition comprising a polymer, an oligomer, a cross-linker, a material having acid labile groups, a material reacting with an acid, a solvent, an acid scavenger, a colorant, a wetting agent, a rheological agent ), Antifoaming agents, fullerene, and fullerene derivatives.

A tenth embodiment disclosed and claimed herein is a photoresist composition of this embodiment wherein the metal is present in the photoresist at about 0.01 wt / wt% to about 25 wt / wt%.

An eleventh embodiment disclosed and claimed herein is directed to a method of forming a photoresist composition comprising applying a photoresist composition of any of the above photoresists, removing the solvent to less than 10% Exposure to an E-beam, optionally post-exposure baking and using a suitable developer to remove the desired area.

Figure 1 shows a graph associated with each element as an elemental periodic table. The line graph on the left shows the relative elastic electron scattering of the elements on the y-axis when irradiated from 10 eV to 100 eV on the x-axis (inelastic electron scattering (red line) of the blue line and elements). The bar graph on the right shows the absorbance, the extinction section and the inelastic section of each element when exposed to light with a wavelength of 13.5 nm.
Figure 2 graphically depicts the light sensitivity of the photoresist of the present invention to which various amounts of tin chloride have been added compared to the same resist without tin chloride added.
Figure 3 graphically illustrates the photosensitivity of the present photoresist with 5% tin chloride added to two positive working resists compared to the same photoresist to which no tin chloride has been added.
Figure 4 compares the photosensitivity of the present disclosure photoresist with ruthenium, silver, iron and tin added graphically to the same photoresist and the same aged photoresist newly made without the addition of the metal .
Figure 5 shows the photoresist of this disclosure to which 1% tin, ruthenium, and tetracoordinate tin have been added as compared to the photoresist with tin and less amount of PAG, Displays photosensitivity graphically.

As used herein, the terms "and" are intended to be inclusive and "or" are not intended to be exclusive unless otherwise specified. For example, the phrase "or, alternatively," is intended to be exclusive.

As used herein, the terms "having", "containing", "including", "comprising", and the like denote the presence of stated elements or features, It is an open term not to exclude features. Singular terms are intended to include singular forms as well as plural forms unless the context clearly indicates otherwise. As used herein, the terms "dry", "dried" and "dried coating" mean having less than 8% residual solvent.

The term "protected polymer" as used herein refers to a polymer that is used in a chemical amplification process, such polymers containing an acid labile functionality such that when exposed to an acid, the polymer having a different functionality Lt; / RTI >

The term "metal" as used herein includes neutral, non-oxidized species, as well as any typical oxidation state that the metal may take.

Surprisingly, it has been found that photoresists have increased photore speed when containing the metals of this disclosure. Without being limited by theory, it is believed that secondary electrons are released when the metal atoms, metal cations, or coordinated metals or coordinated metal cations of this disclosure are exposed to actinic radiation, such as, for example, EUV or electron beams . In both positive and negative photoresists, which rely on the photoacid generator (PAG), these secondary electrons enter the PAG reaction scheme generating acid, which then reacts with other acid sensitive components of the positive or negative photoresist can do. Thus, the exposure of the metal of this disclosure will directly increase the generation of acid if they are components of a composition containing an acid labile functional group or other chemically amplified material, and because of the high level of secondary electrons, This theoretically causes the acid generator to generate more acid, while the increased secondary electron generation in the non-chemically amplified resist will lead to an increase in direct exposure events. An increase of 2 to 10 fold was obtained when the compositions of the present disclosure were used.

Thus, the addition of a metal compound of the present disclosure to a photoresist composition can significantly improve the sensitivity of the material under, for example, actinic radiation, such as EUV radiation. In some cases, the dose-to-size ratio of a particular photoresist composition (as a measure of the photospeed, a lower value indicates that the lower exposure provides a smaller photoresist line feature) By about 15% to about 58%, depending on the amount added. It has also surprisingly been found that, due to the metal-containing composition, an increase in photosensitivity, unlike what is generally expected, did not result in a significant decrease in line-edge roughness (LER) or critical dimension (CD) . Further, without being bound to theory, it is presumed that the metal additives of the present disclosure improve the sensitivity by improving the actinic absorption and / or the regeneration of the secondary electrons in the film. Thus, the metal of the present disclosure typically serves to collect unused radiation and transfer it to the photoacid generator. As a result, the efficiency of the irradiation process is increased and the effective quantum yield of the reaction is improved.

In other aspects of the present disclosure, it is believed that, although not limited to theory, some of the metals of this disclosure may act as energy transfer agents. In this respect, radiation that is not commonly used can be absorbed by the metal and re-emitted to expose the PAG to produce high levels of acid. Thus, again, the efficiency of the irradiation process increases and the effective quantum yield of the reaction increases. In some cases, the metal can act as an energy transfer agent and a secondary electron source, both of which will increase the apparent photosensitivity.

The suitability of a particular metal component depends on the energy of the photons (EUV) or electrons (E-beam) impinging on the metal. Figure 1 shows a periodic table showing a line graph of the elastic (blue line) and inelastic (red line) electron scattering cross sections associated with each element of the periodic table for exposure below 100 eV, where the center line of the graph is 30 eV. The bar chart also shows the light absorbing cross section of each elemental measurement in an EUV exposure of 13.5 nm wavelength. The horizontal line of the bar graph indicates the relative absorption.

A metal exhibiting at least one of a high light absorption cross-sectional area, a median to high inelastic electron scattering profile, and a low to median elastic electron scattering produces the highest photosensitivity when used as a component of a photoresist . For example, as can be seen from the chart, tin shows high light absorption cross-sectional area, medium to high inelastic electron scattering and relatively low elastic electron scattering. Ruthenium exhibits a moderate light absorption cross section at low energy, with intermediate inelastic electron scattering, but exhibits high elastic electron scattering. Photoresist compositions containing tin or ruthenium components exhibit increased photosensitivity.

Suitable metals of the present disclosure include, but are not limited to, elements from Group 3 to Group 17 and Group 3 to Group 6 of the Periodic Table of the Elements (such as scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, A metal selected from the group consisting of selenium, bromine, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, iodine, lanthanide, hafnium, tantalum, tungsten, (Including aluminum, silicon, phosphorus, sulfur, and chlorine) belonging to Group 13 to Group 17 and three cycles (for example, platinum, gold, mercury, lead, bismuth and polonium).

The metal may be neutral or in one or more of its oxidation states (e.g., Pt (0), Pt (II) and / or Pt (IV)).

Surprisingly, it has been found that the same or significantly improved photosensitivity can be obtained by reducing the amount of PAG by the addition of the metals of this disclosure. This may be advantageous in that the PAG is expensive and can cause waste disposal problems.

The metal may be added to the composition as a neutral material or an ionic derivative thereof and may be added to one composition in one or more oxidation states (e.g., Fe (II) and Fe (III)). Ionic derivatives of metals may be added as their salts and such salts are well known in the art and include, for example, their halides, carbonates, borates, oxides, silicates, oxalates, carboxylates, sulfates, sulfonates, Nitrates, nitrates, phosphates, phosphonates, phosphinates, sulfides, hydroxides, arsonates, stilbates, and the like.

One or more metals or ionic derivatives of metals or combinations thereof may be added to the composition. Ionic derivatives of metals or metals may be coordinated to one or more ligands, for example, iron (III) oxalate and iron (III) acetate may be simultaneously added to the composition. There is no limitation on the number of ionic derivatives of metals or metals, and there is no limitation on the number of coordination ligands that can be used as additives for the composition.

The metal may be added as an ionic salt or coordination species in a suitable solvent, for example as a metal-ligand. Certain ligands are known to be more stable under actinic irradiation such as electron beam and / or EUV radiation, for example, bipyridine is more stable than oxalate. In some embodiments, EUV resists based on metal complexes contain less stable ligands such as undergoing photodecomposition. In other embodiments, the metal complex is stable to the chemical radiation additive and can increase the absorption of the chemical radiation and produce secondary electrons. In this embodiment, a more stable ligand can be selected, so that while the metal is generating photoelectrons while absorbing light, the metal remains in a molecularly bonded state and thus can affect other parts of the process (e.g., Less contamination of the photoresist reaction path). Examples include, but are not limited to, for example, acetylacetonate, bipyridine, ethylenediamine, imidazole, phenanthroline ligand.

There are many materials that can be used to coordinate metals, also known as ligands. Ligands are generally derived from charge-neutral precursors and are represented by oxides, amines, phosphines, sulfides, carboxylic acids, esters, hydroxides, alkenes, and the like. Denticity refers to the number of times a ligand binds to a metal through a non-contiguous donor site. Many ligands are capable of binding metal ions through a number of sites because they are usually ligands with more than one atom having a lone pair. Ligands that bind through more than one atom are often called chelating. Ligands binding through two sites are classified as bidentate, and ligands binding through three sites are classified as tridentate.

Chelating ligands are usually formed by linking donor groups through an organic linker. An example involving ethylenediamine includes a classical bidentate ligand derived from the linkage of two ammonia groups and an ethylene (-CH ₂ CH ₂ -) linker. A classic example of a polydentate ligand is EDTA, a six-position chelating agent, which can be bound through six sites, completely surrounding some metals.

Complexes of multidentate ligands are called chelate complexes. They tend to be more stable than complexes derived from monodentate ligands. The chelate ligand at least partially surrounds the central metal and forms a large ring which bonds to it, leaving a central atom at the center of the larger ring. The higher the rigid denticity, the more stable the macroreticular complexes, for example in macrocyclic complexes such as heme: the iron atom is at the center of the porphyrin macrocycle and the tetra Is bonded to four nitrogen atoms of a pyrrole macrocycle. A very stable dimethylglyoxymate complex of nickel is a synthetic macrocyclic ring derived from the anion of dimethylglyoxime.

Photoresists suitable for this application are well known in the art, such as negative resists based on photoacid generators that cause crosslinking during exposure, rendering them insoluble in the developer, while non-exposed materials can be developed and removed . Such resists include, for example, resists containing materials with acid labile groups. Many examples are disclosed in the literature. Positive acting photoresists and chemically amplified photoresists may also be used. In these resists, PAG is used to generate acids that react with acid labile groups, increasing the solubility of the composition in suitable developers. Positive photoresists useful in the present disclosure are well known in the art.

Without being bound by theory, metals and / or metal complexes suitable for the application of this disclosure may not be particularly reactive to chemical radiation, such as electron beams and / or EUV. They can act as inert generators of secondary electrons that occur due to the interaction of other species in the composition during the process.

Metals or metals may be added to the photoresist composition in an amount of 0.1 wt% to 25.0 wt% based on the solids.

In some embodiments, the composition of the application of this disclosure comprises malonate. In another embodiment, a composition of application of the present disclosure comprises an adduct of an imine-amine material and malonate. Specific examples of these materials are described in U.S. Patent No. 9,229,322 and U.S. Patent No. 9,122,156 to Robinson et al., Both of which are incorporated herein by reference.

PAGs useful in this disclosure are well known in the art and include, without limitation, onium salt compounds (e.g., sulfonium salts, phosphonium salts or iodonium salts), sulfonimide compounds, halogen- , An ester sulfonate compound, a quinone diazide compound, a diazomethane compound, a dicarboximidylsulfonic acid ester, an ylideneaminooxysulfonic acid ester, a sulfanediazomethane, or a mixture thereof.

Methods of using the photoresist of this disclosure are well known in the art. These include spin-coating a resist on a wafer prepared by a number of processes known in the art, drying in a predetermined dry state, lithographically exposing to EUV or electron beam radiation, optionally ), Baked after exposure, and developed in a suitable known developer to produce a lithographic pattern.

<Examples>

Examples 1-4:

(O-cresyl-glycidyl ether) -co-formaldehyde] 0.2 part of an adduct of malonate and an imine-amine material (prepared in US Pat. No. 9,229,322 to Robinson, et al. And 1.0 part of triphenylsulfonium tosylate, and supplemented with ethyl lactate to make a concentration of 12.5 g / L. Diphenyliodonium 4-methylbenzenesulfonate was added in an amount of 5 wt%. To this mixture were added 0%, 1%, 2% and 3% by volume of a 10 g / L tin chloride solution in ethyl lactate. The composition was spin coated on a silicon wafer at 3000 rpm to obtain a 19 nm film thickness. Baking was applied after application at 105 ° C for 5 minutes. After the desired exposure, post-exposure baking was applied at 90 캜 for 3 minutes. The unexposed area was removed using n-butyl acetate. Exposure was performed in an EUV interference lithography tool.

The results are shown in Fig. As can be seen, the addition of 2% and 3% by volume of the tin chloride solution significantly increased the photospeed, resulting in a given CD or line width. Samples with 1 wt% tin chloride showed no improvement that could indicate a threshold for improved sensitivity, such as overcoming the level of electronic elasticity.

Example 5:

5% chloride chloride in a 10 g / L solution in ethyl lactate was added to two different commercial positive working photoresists and processed according to the manufacturer's instructions, which included a phenomenon of 0.26 N TMAH. As can be seen from Figure 3, the light sensitivity of the resist it was increased significantly with the addition of 5% SnC1 ₂ to the resist.

Examples 6 - 8:

The process of Experiment 1 was repeated using 3% ruthenium chloride, 3% silver nitrate added as an aqueous solution due to solubility limit, and iron (III) chloride. The results are shown in Fig. As can be seen, it is that the photoresist senescence (aging) considerably increases the photosensitivity of the resist, but you can increase the photosensitivity of the resist, or the addition of FeC1 ₃ RuC1 _3. As should be noted, silver did not improve the photosensitivity, which may be due to the fact that silver was added in the form of an aqueous solution, and also because such water has no beneficial effect on the resist. When tin chloride was added as an aqueous solution, the sensitivity was significantly reduced (not shown).

Examples 9-10:

Embodiment of the first process was repeated using a 1% Ally1Ph ₃ Sn or 1% SnCl _2, and reduced to 80% of the originally formulated amount of the PAG. As can be seen from Fig. 5, the addition of tetracoordinate tin organometallic did not improve photosensitivity. However, as can be seen from FIG. 5, addition of 1% tin chloride with a decrease in the PAG level significantly increases the photosensitivity. As indicated above, the addition of 1% tin chloride did not affect the photosensitivity. This also demonstrates the synergistic effect of the present disclosure, in the photoresist, with the PAG.

Claims (17)

A photoresist composition comprising at least one metal component, wherein the metal component exhibits a high EUV light absorption cross-section, medium to high inelastic electron scattering and low to intermediate elastic scattering coefficients. The method of claim 1 wherein the at least one metal is selected from the group consisting of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, bromine, yttrium, zirconium, niobium, molybdenum Tin, rhenium, rhenium, osmium, iridium, platinum, gold, mercury, lead, bismuth, and the like; Group 3 to Group 17 and Periodic Table of Elements with 3 to 6 cycles, including polonium; And an elemental periodic table of Groups 13 to 17 and three cycles, including aluminum, silicon, phosphorus, sulfur and chlorine. 3. The photoresist composition of claim 2, wherein the at least one metal comprises a metal salt. 3. The photoresist composition of claim 2, wherein the at least one metal comprises a coordination complex. 3. The photoresist composition of claim 2, wherein the at least one metal comprises a metal-containing ligand. 3. The photoresist composition of claim 2, wherein the at least one metal salt comprises an oligomeric or polymeric ligand. 3. The photoresist composition of claim 2, wherein the photoresist composition comprises a negative working photoresist. 3. The photoresist composition of claim 2, wherein the photoresist composition comprises a positive working photoresist. 3. The photoresist composition of claim 2, wherein the photoresist has sensitivity to radiation comprising EUV radiation. 3. The photoresist composition of claim 2, wherein the photoresist has sensitivity to electron beam radiation. 3. The photoresist composition of claim 2, wherein the at least one metal comprises at least one EUV stable complexing material. 3. The photoresist composition of claim 2, wherein the at least one metal complex comprises at least one EUV unstable complexing material. 3. The photoresist composition of claim 2, further comprising a photoacid generator. The photoresist composition of claim 2, further comprising at least one of a malonate, a malonate-imine adduct or a malonate-amine-imide adduct. The process according to claim 2, wherein the polymer is selected from the group consisting of polymers, oligomers, crosslinkers, materials having an acid labile group, materials reacting with acids, solvents, acid scavengers, colorants, wetting agents, rheological agents, defoamers, fullerenes, Wherein the photoresist composition further comprises at least one photoresist composition. 3. The photoresist composition of claim 2, wherein the metal is present in the photoresist at about 0.01 wt / wt% to about 25 wt / wt%. A method for enhancing sensitivity of a photolithographic process, comprising the steps of:
(a) applying the photoresist of claim 2 and removing at least 90% of the solvent;
(b) exposing the applied photoresist to actinic radiation or electron beam radiation; And
(c) removing the desired region using the developer.

Images