KR100709330B1 - Thermally cured underlayer for lithographic application - Google Patents

Abstract

A polymer comprising a hydroxy group and an amino crosslinking agent and a thermal acid generator, wherein the polymer comprising a hydroxy group has the following formula,

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is either unsubstituted or a substituent selected from the group consisting of a C ₆ -C ₁₄ aryl acrylate group or a C ₆ -C ₁₄ aryl methacrylate group substituted with a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group ; R ³ is any one selected from the group consisting of C ₁ -C ₈ alkyl acrylate groups, methacrylate groups or C ₆ -C ₁₄ aryl groups with hydroxy functionality, and R ⁴ is C ₁ -C ₁₀ linear or branched Alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And m is approximately 40 to 70, n is approximately 15 to 35, o is a polymer comprising m, n, and o units of approximately 15 to 25; Coating is initiated.

Thermal curing, undercoat, photoresist, hydroxyl group, substrate

Description

Thermally cured underlayer for lithographic applications

FIELD OF THE INVENTION The present invention relates to deep UV lithography used in semiconductor manufacturing, and more particularly to an undercoat layer for a chemically amplified bilayer resist system.

Integrated circuit manufacturing relies on the use of photolithography to form interconnects with high performance components of microelectronics. Until recently, g-line (436 nm) and l-line (365 nm) wavelengths of light have been used in most microlithography applications. However, in order to obtain smaller resolutions, the wavelengths of light used in microlithography in semiconductor manufacturing have been reduced to the deep UV regions of 254nm and 193nm. The problem with using short wavelength ultraviolet wavelengths is that the resists used at higher wavelengths are too absorbing and too dull. Thus, in order to make use of short wavelength ultraviolet wavelengths, new resist materials with low optical absorbance and improved sensitivity have been required.

Recently, chemically amplified resist materials have been developed through the use of acid-labile polymers in order to meet the aforementioned criteria. These materials have shown great prospects for improving resolution. However, chemically amplified resist systems have many disadvantages. One of the problems is standing wave effects, which occur when monochromatic light is reflected off the surface of the reflective substrate during exposure. The formation of standing waves in the resist reduces the resolution and causes a change in the linewidth. For example, standing waves in positive resists tend to cause a foot at the interface of the resist / substrate that reduces the resolution of the resist.

In addition, the profile and resolution of the chemically amplified resist can change due to contamination of the substrate. In particular, this effect occurs when the substrate has a nitride film. This is understood because residual nitrogen-hydrogen bonds on the nitride film deactivate the acid at the nitride / resist interface. This results in an insoluble region in the positive resist and a foot at the resist scumming or resist / substrate interface.

Furthermore, in order to print features less than 0.18 μm, the lithographic aspect ratio requires that the chemically amplified resist film be thin, for example about 0.5 μm or less. Lithographic aspect ratios then require that the resist have significant plasma etch resistance such that the resist image shape can be transferred down to the underlying substrate. However, in order to reduce the absorbance of the chemically amplified resist, aromatic groups such as those present in novolak must be removed, which in turn reduce the etching resistance.

Before the chemically amplified film is applied, the use of an underlayer or undercoat film placed on the substrate can reduce the aforementioned problems. Undercoating absorbs most of the short-wavelength UV light while weakening the normal wave effect. In addition, undercoating prevents deactivation of the acid catalyst at the interface of the resist / substrate. In addition, the undercoat film includes some aromatic groups that provide etching resistance.

In a typical double film resist process, an undercoat film is applied onto a substrate. A chemically amplified resist is then applied on the undercoat film, exposed to short wavelength ultraviolet light, and developed to form an image on the chemically amplified resist topcoat. In order to etch the undercoat in the areas where the chemically amplified resist has been removed by development, a double film resist system is placed in an oxygen plasma etching environment. The chemically amplified resist of the bilayer system preferably includes silicon, thus converting the silicon into silicon dioxide to withstand oxygen plasma etching and thus withstanding the etching process. The resist system can also be used in subsequent processes, such as non-oxygen plasma etching chemistry, after etching the bottom film and then removing the underlying substrate.

Although undercoating weakens standing waves and contamination of the substrate, there are other problems. Firstly, some undercoat films are soluble in the chemically amplified resist solvent component. If there is mixing between the top and the undercoat film, it will adversely affect the resolution and sensitivity of the top resist film.

In addition, if there is a large difference in refractive index between the chemically amplified resist and the undercoat film, light will be reflected off the undercoat film causing a steady wave effect in the resist. Thus, n, the actual part of the refractive indices of the two films, must be essentially matched or their difference minimized, and k, the virtual part of the refractive indices of the two films, must be optimized to minimize the reflectivity effect.

Another problem with undercoats is that they are sometimes too absorbent due to the hybridization of aromatic groups. Some semiconductor fabrication short wavelength ultraviolet exposure means use the same wavelength as light to expose the resist or align the exposure mask to the resist underlayer. If the undercoat is too absorbent, the reflected light needed for alignment is too weak to use. However, if the undercoat film is not sufficiently absorbent, stationary waves will occur. Manufacturers must compete in balance for this purpose.

In addition, some undercoats have very poor plasma etch resistance to plasma chemistry. In order to be commercially viable, the undercoating etch resistance should be comparable to the etch rate of novolak resins.

Furthermore, ultraviolet light exposure is required to form crosslinking of some undercoat films prior to applying the radiation sensitive resist topcoat film. The ultraviolet crosslinking undercoat film has a problem that a long exposure time is required in order to sufficiently form crosslinking. Long exposure times severely suppress throughput and increase the manufacturing cost of integrated circuits. Since ultraviolet light cannot provide uniform exposure, some areas of the undercoat film may be more crosslinked than others. In addition, UV crosslinking exposure means are very expensive and are not included in most resist coating means due to cost and space limitations.

Some undercoat membranes are crosslinked by heat. However, these undercoat films have a problem that they require a high curing temperature and a long curing time before the top layer is applied. In order to be commercially viable, the undercoat film must be cured for less than 180 seconds at temperatures below 250 ° C. After curing, the undercoat must have a high glass transition temperature to withstand the subsequent high temperature processes and must not mix with the resist film.

Therefore, recently, a method of using a thermosetting undercoat in short wavelength ultraviolet lithography using a composition comprising a constant hydroxy-functionalized polymer, a thermal acid generating compound and an amine crosslinking agent This has been proposed. Polymers having hydroxy-functional groups proposed for use in thermally cured underlayer compositions are copolymers of biphenyl methacrylate (BPMA) and 2-hydroxyethyl methacrylate (HEMA). And generally used with thermal acid generating compounds (TAG) such as cyclohexyl tosylate and amine crosslinkers.

However, the proposed thermally cured undercoat (TCU) compositions have the following issues:

(a) propylene glycol mono methyl acetate (PGMEA), ethyl lactate (EL), ethyl ethoxy propionate (EEP), and the like Solubility and compatibility of current-generating 248 nm TCUs in such conventional edge-bead removing (EBR) solvents;

(b) standing waves, which are thought to be due to less than the undercoating and an optimal match of the optical parameters n and k of the substrate and imaging layer IL; And

(c) Summing at the TCU / image layer (IL) interface.

The proposed TCU composition did not completely eliminate standing waves and scumming at the TCU / IL interface, although the optical constants were significantly matched. In addition, methyl methoxy propionate (MMP) has been suggested for use in providing the solubility and edge bead removal properties of TCU polymers, but it is generally not acceptable as a lithographic solvent.

 Summary of the Invention

It is therefore an object of the present invention to provide an EBR compatible thermoset polymer useful for undercoating compositions and undercoating membranes in order to eliminate or reduce the aforementioned disadvantages. Another object of the present invention is to provide a thermosetting polymer which provides a cured undercoat film at a temperature of less than 250 ° C. for less than 3 minutes. Another object of the present invention is to provide an undercoat film which is insoluble in the top resist solvent system, minimizes the reflectance effect, and has an etching rate comparable to novolak.

Other objects, advantages and features of the present invention will become apparent from the following description.

The present invention is directed to an EBR compatible thermosetting polymer comprising a novel hydroxy group, an amino crosslinker and a thermal acid generator. The thermosetting polymer composition is dissolved in a solvent and can be used as an undercoat film of short wavelength ultraviolet lithography.

      The present invention also relates to a photolithographic coated substrate comprising a substrate, a thermally curable undercoat composition on the substrate, and a radiation sensitive resist topcoat on the thermally curable undercoat composition. Furthermore, the present invention is directed to a process of using a photolithographic coated substrate for the manufacture of relief structures.

Generally useful polymers according to the invention have the formula:

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is either unsubstituted or a substituent selected from the group consisting of a C ₆ -C ₁₄ aryl acrylate group or a C ₆ -C ₁₄ aryl methacrylate group substituted with a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group ; R ³ is any one selected from the group consisting of C ₁ -C ₈ alkyl acrylate groups, methacrylate groups or C ₆ -C ₁₄ aryl groups with hydroxy functionality, and R ⁴ is C ₁ -C ₁₀ linear or branched Alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And m is approximately 40 to 70, n is approximately 15 to 35 and o is approximately 15 to 25. The preferred mole percent range is m to 60 to 68, n is 15 to 20 and o is 15 to 20. The aryl group in the above definition is preferably a C ₆ -C ₁₀ aryl group, more preferably a phenyl group. The molecular weight of the polymers of the present invention is generally in the range of about 8,000 to about 100,000, preferably in the range of about 10,000 to about 24,000.

The m, n, and o components confer absorbance, solubility and crosslinking functions when applied as a TCU material. Each monomeric unit is focused on one of the three functions listed above but may affect one or more functions. This effect depends on the specific monomeric unit used. The change in the amount of monomer represented by m in formula (1) changes the plasma etch resistance and absorbance, thereby greatly changing the optical parameter k, and the optical parameter k affects the reflection control of the TCU material. Solubility and etching resistance can be optimized by appropriate selection of comonomers n and o. The crosslinking rate is determined by the amount of monomer represented by n in formula (1). In general, the optimal range of refractive index (n) and complex index (k) values for 248 nm microlithography is about 1.56 to 1.76 and 0.125 to 0.275, respectively.

The present invention provides monomer units of polymers designed to alter solubility and absorbance properties to provide EBR compatible thermoset polymers. Preferably such monomer unit is used in a polymer composed of monomers of ethyleneglycol dicylclopentenenyl methacrylate (EGDCPMA) combined with biphenyl methacrylate (BPMA) and hydroxystyrene (HS). It is provided by, the chemical formula of the three monomers is as follows.

Generally, hydroxystyrene (HS) units use acetoxystyrene (AcSt) of Formula 5 as the polymerization monomer in the polymerization reaction mixture, and after the polymerization takes place, the reaction mixture is subjected to methanol and methanol ( Dilution with sodium methoxide in 10% solution).

Phenolic OH functional group in PHS is involved in crosslinking reaction of melamine or glycoluril type cross-linker with ethylene glycol group in EGDCPMA, and the phenolic functional group in PHS is propylene glycol monomethyl ether It can enhance solubility in ester solvents such as acetates (PGMEA), ethyl lactate (EL), ethyl ethoxy propionate (EEP) and the like. By adjusting the ratio between the monomers of biphenyl methacrylate, acetoxystyrene and ethylene glycol functional groups, the absorbance at 248 nm can be controlled through terpolymerization of acetoxystyrene.

The thermosetting polymer composition includes a monomer unit having a hydroxyl group. Polymers having suitable hydroxy groups can be used, such as polymers comprising monomeric units such as hydroxystyrene, hydroxyalkyl acrylates or hydroxyalkyl methacrylates. Examples of suitable hydroxyalkyl acrylate or methacrylate monomer units include 2-hydroxyethyl acrylate or methacrylate, 3-hydroxypropyl acrylate or methacrylate, 4-hydroxybutyl acrylate or methacrylate Latex, 5-hydroxypentyl acrylate or methacrylate, 6-hydroxyhexyl acrylate or methacrylate, and the like. As hydroxyalkyl acrylate or methacrylate monomer units, although it is possible to use secondary alcohol groups and tertiary alcohol groups or mixtures of primary and secondary or primary, secondary and tertiary alcohol groups, those containing primary hydroxy groups desirable. Suitable examples of secondary alcohols include 2-hydroxypropyl acrylate or methacrylate, 3-hydroxybutyl acrylate or methacrylate, 4-hydroxypentyl acrylate or methacrylate, 5-hydroxyhexyl acrylate Or methacrylates and the like. Preferred hydroxyalkyl acrylates or methacrylates are 2-hydroxyethyl acrylates or methacrylates.

Polymers having hydroxy groups should include aromatic monomer units to balance n and k of the resist, preferably biphenyl acrylate or methacrylate, naphthyl acrylate or methacrylate, and anthracenyl Acrylate or methacrylate. In addition, the thermosetting polymer composition further includes an ethylene glycol ester monomer unit of acrylic acid or methacrylic acid to produce a more soluble polymer. Suitable examples of monomeric units are ethylene glycol methyl ether acrylate and methacrylate, ethylene glycol phenyl ether acrylate and methacrylate, diethylene glycol methyl ether acrylate and methacrylate and the like. Preferably the average molecular weight of the polymer comprising hydroxystyrene, biphenyl methacrylate and 2- (dicyclopentenyloxy) ether acrylate and methacrylate units is between about 8,000 and 40,000, more preferably between 10,000 and 10,000 20,000.

Suitable solvents for undercoating include ketones, ethers, and esters, for example 2-heptanone, cyclohexanone, propylene glycol monoethyl ether acetate, propylene glycol methyl ether acetate, methyl lactate, ethyl lactate, Methyl 3-methoxypropionate, N-methyl-2-pyrrolidone, ethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, and the like.

The present invention relates to an EBR compatible thermosetting polymer composition, which is used for the formation of undercoat films of short wavelength ultraviolet lithography. The thermosetting polymer composition includes a hydroxyl group-containing polymer, an amino crosslinking agent and a thermal acid generator and a solvent. When the composition is heated, the thermal acid generator protonates the amino crosslinking agent with multiple functional groups to generate an acid that makes very strong electrophilic functional groups. This functional group reacts with the hydroxyl group of the polymer having a hydroxyl group to form a cured and crosslinked polymer matrix.

In the present invention, any suitable amino such as methylolated and / or metyrolated and esterified melamine, metyrolated and / or metyrolated and esterified guanamine and the like Crosslinking agents can also be used. The general formula of the preferred amino crosslinker is as follows.

Y in formula 6 is NR ¹⁰ R ¹¹ or a substituted or unsubstituted C ₆ -C ₁₄ aryl group or C ₁ -C ₈ alkyl group; R ⁶ to R ¹ ₁ are independently hydrogen or a group of CH ₂ OR ^{12 in which} the formula —CH ₂ OH or R ¹² is an alkyl group having about 1 to 8 carbons.

Examples of suitable melamine crosslinkers are methoxyalkylmelamines, for example hexamethoxymethylmelamine, trimethoxymethylmelamine, hexamethoxyethylmelamine, tetramethoxyethylmelamine, hexamethoxypropylmelamine, pentamethoxypropylmelamine , And the like. Preferred melamine crosslinkers are hexamethoxymethyl-melamine. Preferred amino crosslinkers are MW100LM melamine crosslinkers from Sanwa Chemical Co. Ltd., Kanaxawa-ken, Japan, Kanazawaken, Japan, and Cytec Industries, West, New Jersey, USA. Patterson, New Jersey) Cymel 303 and Powerlink.

The thermal acid generator of the present invention has the general formula:

R ¹³ in formula (7) is a substituted or unsubstituted alkyl group, cycloalkyl group or aromatic group wherein the substituent is a halogen, alkoxy group, aromatic group, nitro group or amino group, wherein; And R ¹⁴ to R ¹⁸ are independently hydrogen, linear or branched C ₁ to C ₄ alkyl group, alkoxy group, amino group, alkylamino group, aryl group, alkenyl group, halogen, acyloxy group, cyclo Alkyl group, or an annealed cycloalkyl group, aromatic group or heterocyclic group. Preferred thermal acid generators are cyclohexyl p-toluenesulfonate, menthyl p-toluenesulfonate, bornyl p-toluenesulfonate, cyclohexyl triisopropylbenzenesulfonate, cyclohexyl 4-methoxybenzenesulfo Nate. More preferred thermal acid generators are cyclohexyl p-toluenesulfonate, menthyl p-toluenesulfonate and cyclohexyl 2,4,6-triisopropylbenzenesulfonate.

The aforementioned cyclization means that the cycloalkyl, aromatic or heterocyclic ring is connected to the benzene ring of the thermal acid generator, for example, the same as the cyclized aromatic compound shown in the following formula.

The above-mentioned thermal acid generators should not be considered as photoacid generators. Thermal acid generators have a very poor sensitivity to ultraviolet light, so they can not actually be used as photoacid generators in photolithography.

Preferably the thermosetting polymer composition comprises from about 75 to 95% by weight of the polymer having a hydroxy group, more preferably from about 82 to 95% by weight relative to the total solids. The amount of amino crosslinking agent in the thermosetting polymer composition is preferably about 3 to 20% by weight, more preferably about 3 to 6% by weight. The amount of thermal acid generator in the thermosetting polymer composition is preferably about 0.5 to 5% by weight, more preferably about 2 to 4% by weight.

Significant crosslinking should not begin until the thermoset polymer composition of the present invention reaches a temperature of about 50 ° C. Significant crosslinking below 50 ° C. can lead to gel formation at room temperature, thus reducing shelf life of the shelf. Gel formation results in a nonuniform coating and a change in line width across the substrate when the thermoset polymer composition is used as undercoating in microlithography.

The invention also relates to a photolithographic coated substrate comprising a substrate, a thermally curable undercoat composition on the substrate, and a radiation-sensitive resist topcoat on the thermally curable undercoat composition. The thermosetting undercoat composition comprises a thermosetting polymer composition, which comprises a polymer having a hydroxy group, an amino crosslinking agent and a heated acid generator to form a crosslinking matrix. Any of the aforementioned polymers can be used as the polymer having a hydroxyl group.

The invention further relates to a process using a photolithographic coated substrate for the manufacture of a relief structure comprising the following steps. Providing a photolithographic coated substrate while imagewise exposing a radiation-sensitive resist topcoat to actinic radiation; And developing a radiation-sensitive resist topcoat with a developer to form a resist image to form an open area in the radiation-sensitive resist topcoat. In addition, the heat curable undercoat composition may be removed in the open area of the radiation-sensitive resist topcoat developed by a suitable process such as oxygen plasma etching to form an image on the heat curable undercoat composition.

One advantage of thermoset polymer compositions is that they can be cured at temperatures below about 250 ° C. and below about 180 seconds. This makes the compositions particularly useful for commercial functionalization of undercoat films for resist systems that are temperature and time constrained. Preferably the thermoset polymer composition is cured at a temperature between 150 and 250 ° C, more preferably at a temperature between 180 and 220 ° C. Preferable hardening time is 30 to 180 second, More preferably, it is 60 to 120 second.

Both the undercoat and the radiation-sensitive composition are uniformly applied to the substrate by known coating methods. The composition is dissolved in an organic solvent, and the coating is spin-coating, dipping, knife coating, lamination, brushing, spraying, and reverse coating. It is applied by reverse-roll coating method. The coating thickness ranges generally range from about 0.1 to 10 μm or more, more preferably from 0.1 to 1.5 μm for radiation-sensitive resists and from 0.3 to 3.0 μm for undercoat films. After coating application the solvent is generally removed by curing or drying.

Suitable solvents for both undercoating and top radiation-sensitive compositions include ketones, ethers and esters. For example methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, 2-methoxy-1-propylene acetate, 2-methoxyethanol, 2-ethoxyethanol, 2-e Methoxyethyl acetate, 1-methoxy-2-propyl acetate, 1,2-dimethoxy ethane ethyl acetate, cellosolve acetate, propylene glycol monoethyl ether acetate, propylene glycol methyl ether acetate, methyl lactate, ethyl Lactate, methyl pyruvate, ethyl pyruvate, ethyl 3-methoxypropionate, N-methyl-2-pyrrolidone, 1,4-dioxane, ethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether , Diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, and the like. The solvent used for the undercoat and the top photoresist composition should be selected in view of compatibility with the polymer resin in the undercoat and the top photoresist composition. For example, the choice of photoresist composition and its concentration solvent largely depends on the acid reactive polymer, photoacid generator, and coating method. The solvent should be inert and should be capable of dissolving all components in the photoresist, not allowing any chemical reaction with the components, and being able to be removed by drying after coating.

The radiation-sensitive resist topcoat of the present invention may be a suitable radiation-sensitive resist. Typically, chemically amplified resists are sensitive to radiation in the short wavelength ultraviolet region, as discussed in US Pat. Nos. 5,492,793 and 5,747,622. In a double film resist system, it is preferred that the radiation-sensitive resist contains silicon to inhibit oxygen plasma etching.

Radiation-sensitive resists may also include photoacid generating (PAG) compounds. The PAG compound may be of any suitable type, such as sulfonium or iodonium salts, nitro benzyl esters, imidosulfonate esters and the like. PAG is usually included in an amount of about 1 to 10% by weight of the polymer.

 Any suitable photoacid generator compound can be used in the photoresist composition. Photoacid generator compounds are well known and include, for example, onium salts, which are such as diazonium, sulfonium, sulfoxonium and iodonium salts and disulfones. Suitable photoacid generator compounds are disclosed, for example, in US Pat. Nos. 5,558,978 and 5,468,589, which are incorporated herein by reference.

-(p-톨루엔-술포닐옥시)메틸벤조인, 3-(p-톨루엔술포닐옥시)-2-히드록시-2-페닐-1-페닐프로필 에테르, N-(p-도데실벤젠술포닐옥시)-1,8-나프탈이미드 및 N-(페닐-술포닐옥시)-1,8-나프탈이미드이다.Suitable examples of photoacid generators include phenacryl p-methylbenzenesulfonate, benzoin p-toluenesulfonate,

-(p-toluene-sulfonyloxy) methylbenzoin, 3- (p-toluenesulfonyloxy) -2-hydroxy-2-phenyl-1-phenylpropyl ether, N- (p-dodecylbenzenesulfonyl Oxy) -1,8-naphthalimide and N- (phenyl-sulfonyloxy) -1,8-naphthalimide.

,

,

-트리클로로아세토페논과 p-tert-부틸-

,

,

-트리클로로아세토페논과 같은

-할로아실페논, 및 2-히드록시벤조페논 메탄술포네이트와 2,4-히드록시벤조페논 비스(메탄술포네이트)와 같은 o-히드록시아실페논의 술폰 에스테르이다. Other suitable compounds are, for example, o-nitrosobenzoic acid, such as 1-nitrobenzaldehyde and 2,6-nitrobenzaldehyde, such as o-nitrobenzaldehyde, which is actinic radiation potential.

,

,

Trichloroacetophenone and p-tert-butyl

,

,

Such as trichloroacetophenone

Haloacylphenones and sulfone esters of o-hydroxyacylphenones such as 2-hydroxybenzophenone methanesulfonate and 2,4-hydroxybenzophenone bis (methanesulfonate).

Examples of other suitable photoacid generators are triphenylsulfonium bromide, triphenylsulfonium chloride, triphenylsulfonium iodide, triphenylsulfonium hexafluoro phosphate, triphenylsulfonium hexafluoro arsenate Triphenylsulfonium trifluoromethanesulfonate, diphenylethylsulfonium chloride, phenacyldimethylsulfonium chloride, phenacyltetrahydrothiophenium chloride, 4-nitrophenacyltetrahydrothiophenium chloride, And 4-hydroxy-2-methylphenylhexahydrothiopyryllium.

Further examples of suitable photoacid generators that can be used in the present invention include bis- (p-toluenesulfonyl) diazomethane, methylsulfonyl p-toluenesulfonyldiazomethane, 1-cyclo-hexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (1-methylethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) dia Zomethane, 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 2-methyl-2- (p-toluenesulfonyl) propiophenone, 2-methanesulfonyl-2-methyl- (4 -Methylthiopropiophenone, 2,4-methyl-2- (p-toluenesulfonyl) pent-3-one , 1-diazo-1-methylsulfonyl-4-phenyl-2-butanone, 2- (Cyclohexylcarbonyl) -2- (p-toluenesulfonyl) propane, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-cyclohexylsulfonyl-3,3 -Dimethyl-2-butanone, 1-diazo-1- (1,1-dimethylethylsulfonyl) -3,3-dimethyl-2-butanone, 1-acetyl-1- (1-meth Methylethylsulfonyl) diazomethane, 1-diazo-1- (p-toluenesulfonyl) -3,3-dimethyl-2-butanone, 1-diazo-1-benzenesulfonyl-3,3- Dimethyl-2-butanone, 1-diazo-1- (p-toluenesulfonyl) -3-methyl-2-butanone, cyclohexyl 2-diazo-2- (p-toluenesulfonyl) acetate, tert -Butyl 2-diazo-2-benzenesulfonyl acetate, isopropyl-2-diazo-2-methanesulfonyl acetate, cyclohexyl 2-diazo-2-benzenesulfonyl acetate, tert-butyl 2-diazo 2- (p-toluenesulfonyl) acetate, 2-nitrobenzyl p-toluenesulfonate, 2,6-dinitrobenzyl p-toluenesulfonate, 2,4-dinitrobenzyl p-trifluoromethylbenzenesulfo Nate.

Examples of other photoacid generators are hexafluorotetrabromo-bisphenol A, 1,1,1, -tris (3,5-dibromo-4-hydroxyphenyl) ethane and N- (2,4, 6-tribromophenyl) -N (p-toluenesulfonyl) urea.

The photoacid generator compound is generally used in an amount of about 0.0001 to 20% based on the total weight of the polymer solids, and preferably about 1 to 10% by weight of the total weight of the polymer solids.

As a further example, base additives may be added to the photoresist composition. The purpose of the base additive is to remove protons present in the photoresist before being irradiated by actinic radiation. The base prevents attack or cleavage of acid labile groups by inadequate acid, thus increasing the efficiency and stability of the resist. The proportion of base in the composition should be considerably smaller than the photoacid generator since it is not desirable for the base to interfere with the cleavage of the acid reactive groups after the photoresist composition has been irradiated. The preferred proportion of base compound present is in the range of about 3 to 50% by weight of the photoacid generator composition. Suitable examples of base additives include 2-methylimidazole, triisopropylamine, 4-dimethylaminopyridine, 4,4'-diaminodiphenyl ether, 2,4,5 triphenyl imidazole and 1,5 -Diazobicyclo [4,3,0] non-5-ene.

Dyestuffs may be added to the photoresist to increase the absorbance of the radiation of the actinic radiation of the composition. The dye must not contaminate the composition and must be able to withstand process conditions including any thermal treatment. Examples of suitable dyes are fluorenone derivatives, anthracene derivatives or pyrene derivatives. Other specific types of dyes preferred for photoresist compositions are disclosed in US Pat. No. 5,593,812.

The photoresist composition may further comprise traditional additives such as adhesion promoters and surfactants. Those skilled in the art will be able to appropriately select the preferred additives and their concentrations.                 

The invention also relates to a process for forming a pattern on a substrate comprising the following process steps. Applying to the substrate a photoresist coating comprising one of the above compositions; Imagewise exposing the coating with radiation of actinic radiation; The coating is exposed to radiation and the coating area is dissolved from the substrate and the coating is treated with an alkaline aqueous developer until the coating of the imaged photoresist structure remains on the substrate.

The radiation sensitive resist is imagewise exposed to radiation of actinic radiation to produce a relief structure. The term imagewise exposure refers to exposure through a photomask containing a predetermined pattern and exposure by a radiation source of a desired actinic radiation, such as a computer controlled laser beam moving over the surface of a coating substrate, for example through a corresponding mask, to a computer controlled electron beam. It is meant to include both exposure by exposure and exposure by X-rays or UV rays. Imagewise exposure generates an acid in the exposed area of the resist that cleaves the acid reactive groups that make up the water soluble polymer. Preferably, after the imagewise exposure, the chemically amplified resist is subjected to an exposure heat treatment after substantially completing the reaction of the acid reactive group with the photoacid generator.

After exposure of the imagewise of the material and any heat treatment, the exposed area of the top radiation sensitive resist is preferably dissolved and removed in an aqueous developer. The particular developer is selected depending on the type of photoresist, in particular according to the physical properties of the polymer resin or the resulting photolysis products. The developer may include an aqueous base solution to which an organic solvent or a mixture thereof is added. Particularly preferred developers are aqueous alkaline solutions. Aqueous alkali solutions include, for example, alkali metal silicates, phosphates, hydroxides, and carbonates, but in particular tetraalkylammonium hydroxide, and even more preferred tetramethylammonium hydroxide (TMAH). It is also desirable to add relatively small amounts of wetting agents and / or organic solvents to these solutions.

The radiation-sensitive resist used in the bilayer process described above preferably comprises silicon or is incorporated into the resist after development. After the image is formed in the radiation-sensitive resist, the silicon incorporated in the radiation-sensitive resist forms silicon dioxide and is etched away when exposed to oxygen plasma to allow the underlayer coating to be removed in areas not protected by the resist. The substrate is placed in a plasma-etching environment containing oxygen to protect the resist to form a relief structure in the undercoat film.

Subsequent to the double film relief structure after the oxygen plasma step are generally subject to at least one additional processing step that will alter the substrate in areas not covered by the double film coating. Preferably, this treatment step may be implantation of dopants, deposition of other materials on the substrate, or etching of the substrate. This is followed by the removal of the resist coating from the substrate, usually by fluorine / oxygen plasma etching.

Copolymers including BPMA and HEMA which have already been proposed are insoluble in lithographic solvents and EBR compatible solvents such as most PGMEA, EL and the like. The hydroxyl group of HEMA is used as the crosslinking functional group. In preferred terpolymers of the present invention, ie, BPMA, terpolymers comprising AcSt and EGDCPMA (more metabolized to p-hydroxystyrene (HS)), the BPMA units of the polymer are contributes to optimizing the value of k. The PHS unit of a polymer performs two other roles in addition to its absorbance and plasma etching resistance. One of its roles is to provide functional groups for crosslinking that are more effective than hydroxy functional groups in HEMA. Second, HS as an acetoxystyrene precursor is irregularly copolymerized with BPMA, which enhances the solubility of the polymer and alters the block properties of BPMA in the microstructure of the polymer. The ester with at least one ether linkage, which is the third monomer, enhances the solubility of the polymer and increases the etching resistance. The polymer system is compatible with EBR solvents.

The present invention is directed to polymer compositions comprising thermally crosslinkable functional groups that are highly soluble in all EBR compatible solvents. The present invention provides a thermosetting polymer, which is useful for undercoat films of short wavelength ultraviolet lithography. This undercoat membrane polymer can be cured at a temperature below about 220 ° C. and a time of less than about 2 minutes. This undercoating is insoluble in top resist solvent systems and has an etching rate comparable to novolac. The undercoating film polymer composition of the present invention is optimized to minimize reflection at the image / underlayer boundary, and in compositions where scumming and footing can be completely removed by controlling the amount of crosslinking agent in the formulation. By the refractive indices n and k.

The present invention is described by the following examples in parts and percentages by weight unless otherwise indicated, but is not limited to these examples.

The general synthetic procedure used to obtain the polymer of the present invention by polymerization in tetrahydrofuran is as follows.

The mixture of monomer, initiator and chain transfer agent is placed in a round bottom flask with reflux condenser and gas inlet and dissolved in 150 g of THF under N ₂ flow. The mixture is heated to 65 ° C. with stirring and kept at the same temperature for 20 hours under N ₂ . The reaction mixture is then cooled to room temperature and aliquots are taken for GPC. The reaction mixture is diluted in 60 ml of methanol and sodium methoxide (10% solution) dissolved in methanol is added for metanosis. The mixture is refluxed and the byproduct methyl acetate is continuously removed by azeoteropic distillation using a Dean-Stark trap for 4 hours. After cooling to room temperature, 20 g of Amberlyst 15 resin (ion exchange resin available from Rohm & Haas) for the ion exchange of sodium is added to the mixture and stirred for 3 hours. Filter the resin and slowly pour 4 liters of distilled water into the solution. The solid polymer is separated by filtration and redissolved in 300 ml of THF. The polymer is precipitated in 2 liters of isopropanol. After filtration, the solid is dried at 60 ° C. for 24 hours in a vacuum.

The general analysis method is as follows.

Molecular weight and molecular weight distribution were determined by Waters Corp. (GPC V Software) of Millennium (GPC V Software) equipped with Phenogel-10, 7.8 × 250 mm column with 10-4A, 500A and 50A (from Phenomena) and THF eluent. It was measured using a liquid chromatograph (refractive index). Thermal decomposition measurements (TGA) are performed using a Perkin-Elmer thermal gravimetric analyzer. The glass transition temperature (Tg) of the polymer was measured using a Perkin-Elmer Pyris 1 Differential Scanning Calorimeter at a heating rate of 10 ° C./min.

Polymer Example 1

Monomer [4-biphenyl methacrylate (72.37 g, 0.303 mol), acetoxy styrene (10.56 g, 0.065 mol) and ethylene glycol dicyclopentenyl ether methacrylate (17.07 g, 0.065 mol)] and initiator VAZO 67 (6.00 g, 6.0 weight% based on monomer) and a mixture of 1-dodecanethiol (1.80 g, 30 weight% based on initiator) as a chain transfer agent are polymerized according to the general procedure described above. Transesterification uses 4.0 g of sodium methoxide solution. Yield: 91.3 g, 94%. Mw = 14,666; Mw / Mn = 1.92. TGA: 5% mass loss at 310 ° C. Tg: 128 ° C. The composition of the polymer is mol% with 69% biphenyl methacrylate units, 16% hydroxystyrene units and 15% ethylene glycol dicyclopentenyl ether methacrylate units.

Polymer Example 2

Monomer [4-biphenyl methacrylate (62.74 g, 0.263 mol), acetoxy styrene (14.23 g, 0.087 mol) and ethylene glycol dicyclopentenyl ether methacrylate (23.03 g, 0.087 mol)] and initiator VAZO 67 (6.00 g, monomer weight (vs) 6.0 weight percent) and a mixture of 1-dodecanethiol (1.80 g, 30 weight percent based on initiator), which is a chain transfer agent, are polymerized according to the general procedure described above. The transesterification reaction uses 5.0 g of sodium methoxide solution. Yield: 91.5 g, 95%. Mw = 13,715; Mw / Mn = 1.97. TGA: 5% mass loss at 305 ° C. Tg: 124 ° C. The composition of the polymer is mol% with 60% biphenyl methacrylate units, 19% hydroxystyrene units and 21% ethylene glycol dicyclopentenyl ether methacrylate units.

Polymer Example 3

Monomer [4-biphenyl methacrylate (54.09 g, 0.227 mol), acetoxy styrene (22.09 g, 0.136 mol) and ethylene glycol dicyclopentenyl ether methacrylate (23.82 g, 0.09 mol)] and initiator VAZO 67 (6.00 g, 6.0 weight% based on monomer) and a mixture of 1-dodecanethiol (1.80 g, 30 weight% based on initiator) as a chain transfer agent are polymerized according to the general procedure described above. The transesterification reaction uses 6.0 g of sodium methoxide solution. Yield: 85.5 g, 91%. Mw = 11,262; Mw / Mn = 1.88. TGA: 5% mass loss at 300 ° C. Tg: 118 ° C. The composition of the polymer is mol% with 51% biphenyl methacrylate units, 28% hydroxystyrene units and 21% ethylene glycol dicyclopentenyl ether methacrylate units.

Polymer Example 4

Chain transfer agent with monomer [biphenyl methacrylate [BPMA] (37.74 g, 0.158 mol), acetoxy styrene (8.54 g, 0.0527 mol) and ethylene glycol dicyclopentenyl ether methacrylate (13.82 g, 0.0527 mol) Phosphorous 1-dodecanethiol (1.08 g, 30 wt% relative to initiator) is dissolved in 83.6 g of PGMEA (40% solids) under N ₂ flow in a 500 mL round bottom flask equipped with a reflux condenser and gas inlet. The mixture is heated to 70 ° C. Subsequently, VAZO 67 [free radical initiator, DuPont, 2,2'-azobis (2-methylbutyronitrile)] (3.6 g, 6% by weight based on monomer used) in 6.4 g of PGMEA was added to the reaction mixture. Is added slowly over 15 minutes and stirred under N _{2 for} 24 hours. The disappearance of BPMA can be observed with GPC using a UV detector at 254 nm. After 24 hours, the residual BPMA is less than 0.1%. The reaction mixture is cooled to room temperature. Thereafter, 2.0 g (10 wt%) of sodium methoxide in methanol and 50 mL of methanol are added dropwise to the flask. The reaction mixture is refluxed for 3 hours and about 25 mL of methanol is removed by azeotropic distillation using a Dean-Stark trap. The solution is cooled to room temperature and 10 g of Amberlyst 15 resin is added dropwise. The reaction mixture is stirred for 2 hours and the resin is separated by filtration. The solution is distilled to half its volume under vacuum below 60 ° C. to remove methanol and by-product propylene glycol methyl ether. Finally, adding PGMEA to the distilled liquid yields 30% by weight solid solution. Mw = 15,700; Mw / Mn = 1.95; And the composition of the polymer is mol%, 59% for biphenyl methacrylate units, 20% for hydroxystyrene units and 21% for ethylene glycol dicyclopentenyl ether methacrylate units.

Polymer Example 5

Chain transfer agent with monomer [biphenyl methacrylate [BPMA] (37.74 g, 0.158 mol), acetoxy styrene (8.54 g, 0.0527 mol) and ethylene glycol dicyclopentenyl ether methacrylate (13.82 g, 0.0527 mol) Phosphorous 1-dodecanethiol (1.08 g, 30 wt% of initiator) is dissolved in 83.6 g of PGMEA (40% solids) under N ₂ flow in a 500 mL round bottom flask equipped with a reflux condenser and a gas inlet. The mixture is heated to 70 ° C. Subsequently, VAZO 67 [free radical initiator, DuPont, 2,2'-azobis (2-methylbutyronitrile)] (3.6 g, 6% by weight of monomer used) in 6.4 g of PGMEA was added to the reaction mixture. Add dropwise slowly over 15 minutes. The temperature is then slowly increased to 80 ° C. and stirred under N _{2 for} 4 hours. The disappearance of BPMA can be observed with GPC using a UV detector at 254 nm. After 3 hours the remaining BPMA is less than 0.1%. The mixture is cooled to room temperature. Thereafter, 2.0 g (10 wt%) of sodium methoxide in methanol and 50 mL of methanol are added dropwise to the flask. The reaction mixture is refluxed for 3 hours and approximately 25 mL of methanol is removed by azeotropic distillation using a Dean-Stark trap. The solution is then cooled to room temperature and 10 g Amberlyst 15 resin is added dropwise. The reaction mixture is stirred for 2 hours and the resin is separated by filtration. The solution is distilled to half its volume under vacuum below 60 ° C. to remove methanol and by-product propylene glycol methyl ether. Finally, PGMEA is added dropwise to the distilled liquid to obtain 30% by weight solid solution. Mw = 11,044; Mw / Mn = 2.11; And the composition of the polymer is mol%, 60% of biphenyl methacrylate units, 19% of hydroxystyrene units and 21% of ethylene glycol dicyclopentenyl ether methacrylate units.

In Examples 1 to 5, the undercoat formulation of the polymer is prepared by the following example.                 

Undercoat formulations 1

For 100 g of undercoat solution (15% by weight total solids), 14.02 g of polymer of Example 1, 4.0 g of MW100LM (melamine cross linker, Sanwa Chemical Co., Kanasawa, Japan) solution (20% by weight in PGMEA) Solution) and 1.875 g of cyclohexyl tosylate thermal acid solution (20 wt% solution in PGMEA) are mixed and dissolved in 80.1 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rolled overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 2

For 100 g of undercoating solution (15 wt% total solids), 14.02 g of polymer of Example 2, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 80.1 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

 Undercoat Formulation 3

For 100 g of undercoating solution (15 wt% total solids), 14.02 g of the polymer of Example 3, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 80.1 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 4                 

For 100 g of undercoat solution (15% by weight total solids), 46.75 g of the polymer solution of Example 4, 4.0 g of MW100LM crosslinker solution (20% by weight solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator The solution (20 wt% solution in PGMEA) is mixed and dissolved in 47.4 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

    Undercoat Formulation 5

For 100 g of undercoating solution (15 wt% total solids), 46.75 g of the polymer solution of Example 5, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator The solution (20 wt% solution in PGMEA) is mixed and dissolved in 47.4 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

    Undercoat Formulation 6

For 100 g of undercoating solution (15 wt% total solids), 14.33 g of polymer of Example 1, 2.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 81.8 g of PGMEA. The mixture (polymer / crosslinker / TAG = 95.5 / 2.0 / 2.5%) is rotated overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 7                 

For 100 g of undercoating solution (15 wt% total solids), 14.18 g of polymer of Example 1, 3.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 81.0 g of PGMEA. The mixture (polymer / crosslinker / TAG = 94.5 / 3.0 / 2.5%) is rotated overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 8

For 100 g of undercoating solution (15 wt% total solids), 13.83 g of the polymer of Example 1, 6.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 78.4 g of PGMEA. The mixture (polymer / crosslinker / TAG = 91.5 / 6.0 / 2.5%) is rotated overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 9

For 100 g of undercoating solution (15 wt% total solids), 13.13 g of the polymer of Example 1, 10.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 75.0 g of PGMEA. The mixture (polymer / crosslinker / TAG = 87.5 / 10.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 10

For 100 g of undercoating solution (15 wt% total solids), 14.02 g of the polymer of Example 1, 4.0 g of Powderlink crosslinker solution (20 wt% solution in PGMEA) and 1.875 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 80.1 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.5 / 4.0 / 2.5%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 11

For 100 g of undercoating solution (15 wt% total solids), 14.10 g of the polymer of Example 1, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 2.25 g cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 79.8 g of PGMEA. The mixture (polymer / crosslinker / TAG = 94.0 / 4.0 / 3.0%) is rotated overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulations 12

For 100 g of undercoating solution (15 wt% total solids), 13.95 g of polymer of Example 1, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 2.25 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 79.8 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.0 / 4.0 / 3.0%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulations 13

For 100 g of undercoating solution (15% by weight total solids), 13.80 g of polymer of Example 1, 4.0 g of MW100LM crosslinker solution (20% by weight solution in PGMEA) and 3.0 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 79.2 g of PGMEA. The mixture (polymer / crosslinker / TAG = 93.0 / 4.0 / 4.0%) is rotated overnight and the undercoating solution is filtered twice through a 0.1 μm Teflon filter.

Undercoat Formulation 14

For 100 g of undercoating solution (15 wt% total solids), 13.65 g of polymer of Example 1, 4.0 g of MW100LM crosslinker solution (20 wt% solution in PGMEA) and 3.75 g of cyclohexyl tosylate thermal acid generator solution (20 wt.% Solution in PGMEA) is mixed and dissolved in 78.6 g of PGMEA. The mixture (polymer / crosslinker / TAG = 91.0 / 4.0 / 5.0%) is rotated overnight and the undercoat solution is filtered twice through a 0.1 μm Teflon filter.

The general procedure for lithographic testing of undercoat formulations is as follows.

The undercoat is spin-coated with the undercoating formulation on the silicon wafer and baked at 205 ° C. for 90 seconds to produce a film of 0.50 μm. On top of the undercoat, a spin film (TIS 2000, a chemically amplified resist available from Arch Chemicals, Inc., Norwalk, CT) was spin coated and heated at 135 ° C. for 1 minute to form a 0.25 μm film. The coated wafer is then patternwise exposed using an Ultratec 248nm Stepper. The wafer is heated after exposure at 125 ° C. for 1 minute and developed for 60 seconds in a 0.262 normal concentration aqueous TMAH. Rinse the wafer with deionized water and spin while drying. The pattern is analyzed by scanning electron microscopy (SEM). The SEM image shows that the bilayer resist can resolve shapes as small as 0.13 μm.

General lithographic performance of the TIS-2000 composition of the present invention is as follows:

Light speed range: 30-40 (mJ / cm 2);                 

Resolution range: 0.120 to 0.130 (μm), and

Depth of focus: 0.70 to 1.0 (0.130 μm shape)

The lithographic test results of the compositions are shown in Table 1 below.

Summary of formulations and evaluation of image quality of undercoat formulations Example Polymer Polymer (grams) Crosslinking agent Crosslinker (gram) 20% by weight solid Thermal acid generator (grams) 20% by weight solid PGMEA (grams)  Separate line (0.13 μm) resolution, resist / undercoat (IL / UL) interface quality One Polymer 1 14.02 MW100LM 4.0 1.875 80.1 No putting at IL / UL interface 2 Polymer 2 14.02 MW100LM 4.0 1.875 80.1 No putting at IL / UL interface 3 Polymer 3 14.02 MW100LM 4.0 1.875 80.1 Summing at IL / UL interface 4 Polymer 4 14.02 MW100LM 4.0 1.875 80.1 No putting at IL / UL interface 5 Polymer 5 14.02 MW100LM 4.0 1.875 80.1 No putting at IL / UL interface 6 Polymer 1 14.33 MW100LM 2.0 1.875 81.8 Line pattern breakage 7 Polymer 1 14.18 MW100LM 3.0 1.875 81.0 Putting 8 Polymer 1 13.83 MW100LM 6.0 1.875 78.4 No putting at IL / UL interface 9 Polymer 1 13.13 MW100LM 10.0 1.875 75.0 Putting 10 Polymer 1 14.02 Powderlink 4.0 1.875 80.1 No putting at IL / UL interface 11 Polymer 1 14.10 MW100LM 4.0 1.5 80.4 No putting at IL / UL interface 12 Polymer 1 13.95 MW100LM 4.0 2.25 79.8 No putting at IL / UL interface 13 Polymer 1 13.80 MW100LM 4.0 3.0 79.2 No putting at IL / UL interface 14 Polymer 1 13.65 MW100LM 4.0 3.75 78.6 T-topping

The SEM results show that scum or foot appears at the resist / undercoat interface in formulations containing high crosslinked site (hydroxy styrene) polymers. Similarly, SEM results show that the line pattern collapses at low concentrations of melamine crosslinkers, presumably due to insufficient curing of the undercoat which leads to mixing at the resist / undercoat interface. When crosslinkers were used at higher concentrations in the formulation, scum formation and a footed profile were observed.

Although the present invention has been described with reference to specific embodiments of the invention, it is possible to change, change and change without departing from the spirit and scope of the inventive concept disclosed herein. Accordingly, the invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.

Claims (24)

With the formula

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is unsubstituted or substituted C ₆ -C ₁₄ aryl acrylate and C ₆ -C ₁₄ aryl methacrylate wherein the substituent is any one selected from the group consisting of a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group A monofunctional group, such as a monomer unit, selected from the group consisting of groups and having m as a subscript; R ³ is any one selected from the group consisting of a C ₁ -C ₈ alkyl acrylate group or a methacrylate group having a hydroxy functional group and a C ₆ -C ₁₄ aryl group and a monofunctional group such as a monomer unit having n as a subscript , R ⁴ is C ₁ -C ₁₀ linear or branched alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And m is approximately 40 to 70, n is approximately 15 to 35, and o is approximately 15 to 25; m, n, and o units, wherein the polymer comprises a hydroxy group. The method of claim 1, The monomer unit having m as a subscript is a biphenyl acrylate or methacrylate unit, and R ⁵ is a dicyclopentenyl polymer comprising a hydroxy group. The method of claim 1, The monomer unit having n as a subscript is a hydroxystyrene unit, and R ⁵ is a dicyclopentenyl polymer comprising a hydroxy group. The method of claim 1, The monomer unit having m as a subscript is biphenyl-acrylate or methacrylate unit; The monomer unit having n as a subscript is a hydroxystyrene unit; The monomer unit having o as a subscript is ethylene glycol dicyclopentenyl-acrylate or methacrylate unit; Polymer comprising a hydroxy group, characterized in that. The method of claim 4, wherein The monomer unit having o as a subscript is an ethylene glycol dicyclopentenyl methacrylate unit, and the monomer unit having m as a subscript is a biphenyl methacrylate unit. The method of claim 4, wherein The polymer having a hydroxyl group, characterized in that the average molecular weight of the polymer is about 10,000 to 24,000. A polymer comprising a hydroxy group, an amino crosslinking agent and a thermal acid generator, the polymer containing a hydroxy group has the following formula,

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is unsubstituted or substituted C ₆ -C ₁₄ aryl acrylate or C ₆ -C ₁₄ aryl methacrylate wherein the substituent is any one selected from the group consisting of a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group Monofunctional groups, such as monomer units, which are selected from the group consisting of groups and have m as a subscript; R ³ is any one selected from the group consisting of a C ₁ -C ₈ alkyl acrylate group or a methacrylate group having a hydroxy functional group and a C ₆ -C ₁₄ aryl group and a monofunctional group such as a monomer unit having n as a subscript , R ⁴ is C ₁ -C ₁₀ linear or branched alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And m is approximately 40 to 70, n is approximately 15 to 35, and o is approximately 15 to 25; a thermosetting polymer composition comprising m, n, and o units. The method of claim 7, wherein The monomer unit having m as a subscript is a biphenyl-acrylate or methacrylate unit, and R ⁵ is dicyclopentenyl. The method of claim 7, wherein The monomer unit having n as a subscript is a hydroxystyrene unit, and R ⁵ is dicyclopentenyl. The method of claim 9, The monomer unit having m as a subscript is biphenyl-acrylate or methacrylate unit; The monomer unit having n as a subscript is a hydroxystyrene unit; The monomer unit having o as a subscript is ethylene glycol dicyclopentenyl-acrylate or methacrylate unit; thermosetting polymer composition, characterized in that. The method of claim 9, The monomer unit having o as a subscript is an ethylene glycol dicyclopentenyl methacrylate unit, and the monomer unit having m as a subscript is a biphenyl methacrylate unit. The method of claim 5, Thermosetting polymer composition, characterized in that the average molecular weight of the polymer containing a hydroxy group is about 10,000 to 24,000. (a) a substrate, (b) thermal curing undercoat on the substrate, and (c) comprising a radiation-sensitive resist topcoat on the undercoat, The thermal curing undercoat includes a polymer comprising a hydroxyl group and a thermosetting composition including an amino crosslinking agent and a thermal acid generator, wherein the polymer including the hydroxyl group has the following formula,

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is unsubstituted or substituted C ₆ -C ₁₄ aryl acrylate and C ₆ -C ₁₄ aryl methacrylate wherein the substituent is any one selected from the group consisting of a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group Monofunctional groups, such as monomer units, which are selected from the group consisting of groups and have m as a subscript; R ³ is any one selected from the group consisting of a C ₁ -C ₈ alkyl acrylate group or a methacrylate group having a hydroxy functional group and a C ₆ -C ₁₄ aryl group and a monofunctional group such as a monomer unit having n as a subscript , R ⁴ is C ₁ -C ₁₀ linear or branched alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And m is approximately 40 to 70, n is approximately 15 to 35, and o is approximately 15 to 25; a photolithographic sensitive coating substrate, wherein the polymer comprises m, n, and o units. The method of claim 13, The monomer unit having m as a subscript is a biphenyl-acrylate or methacrylate unit, and R ⁵ is dicyclopentenyl. The method of claim 13, The monomer unit having n as a subscript is a hydroxystyrene unit, and R ⁵ is dicyclopentenyl. The method of claim 13, The monomer unit having m as a subscript is biphenyl-acrylate or methacrylate unit; The monomer unit having n as a subscript is a hydroxystyrene unit; The monomer unit having o as a subscript is ethylene glycol dicyclopentenyl acrylate or methacrylate unit; photolithography sensitive coating substrate, characterized in that. The method of claim 16, The monomer unit having o as a subscript is an ethylene glycol dicyclopentenyl methacrylate unit, and the monomer unit having m as a subscript is a biphenyl methacrylate unit. The method of claim 16, The photolithography sensitive coating substrate, characterized in that the average molecular weight of the polymer containing a hydroxyl group is 10,000 to 24,000. (a) (1) a substrate, (2) thermal curing undercoat on the substrate, and (3) comprising a radiation-sensitive resist topcoat on the undercoat; The thermosetting undercoat includes a thermosetting composition including a polymer containing a hydroxy group, an amino crosslinking agent and a thermal acid generator, and the polymer including the hydroxy group has the following formula,

R ¹ is any one selected from the group consisting of hydrogen or a methyl group; R ² is unsubstituted or substituted C ₆ -C ₁₄ aryl acrylate or C ₆ -C ₁₄ aryl methacrylate wherein the substituent is any one selected from the group consisting of a phenyl group, a C _1-4 alkyl group or a C _1-4 alkoxy group Monofunctional groups, such as monomer units, which are selected from the group consisting of groups and have m as a subscript; R ³ is any one selected from the group consisting of a C ₁ -C ₈ alkyl acrylate group or a methacrylate group having a hydroxy functional group and a C ₆ -C ₁₄ aryl group and a monofunctional group such as a monomer unit having n as a subscript , R ⁴ is C ₁ -C ₁₀ linear or branched alkylene; p is an integer from 1 to 5 provided that there are no more than 30 carbon atoms in [-R ⁴ O-] _p ; R ⁵ is selected from the group consisting of C ₁ -C ₁₀ linear, branched or cyclic alkyl groups, substituted or unsubstituted C ₆ -C ₁₄ aryl groups, or substituted or unsubstituted C ₇ -C ₁₅ alicyclic hydrocarbons Any one selected; And forming a coated substrate which is a polymer comprising m, n, and o units wherein m is approximately 40 to 70, n is approximately 15 to 35, and o is approximately 15 to 25; (b) imagewise exposing the radiation-sensitive topcoat with radiation of actinic radiation; And (c) developing the radiation-sensitive top coating with a developer to form a resist image. The method of claim 19, The monomer unit having m as a subscript is a biphenyl-acrylate or methacrylate unit, and R ⁵ is a dicyclopentenyl method for producing a relief structure. The method of claim 19, The monomer unit having n as a subscript is a hydroxystyrene unit, and R ⁵ is a method for producing a relief structure, characterized in that dicyclopentenyl. The method of claim 19, The monomer unit having m as a subscript is biphenyl-acrylate or methacrylate unit; The monomer unit having n as a subscript is a hydroxystyrene unit; The monomer unit having o as a subscript is ethylene glycol dicyclopentenyl-acrylate or methacrylate unit; a method for producing a relief structure, characterized in that. The method of claim 22, The monomer unit having o as a subscript is an ethylene glycol dicyclopentenyl methacrylate unit, and the monomer unit having m as a subscript is a biphenyl methacrylate unit. The method of claim 22, Method for producing a relief structure, characterized in that the average molecular weight of the polymer containing a hydroxy group is 10,000 to 24,000.