JP2003532932A - Polymers used in photoresist compositions for microlithography - Google Patents

Abstract

  (57) [Summary] A nitrile / vinyl ether-containing polymer for a photoresist composition and a microlithography method using the photoresist composition will be described. These photoresist compositions comprise: 1) at least one ethylenically unsaturated compound comprising vinyl ether; and 2) a nitrile-containing compound, such as acrylonitrile, which imparts high ultraviolet (UV) transparency and developability to a basic medium. And In some embodiments, these photoresist compositions further include a fluoroalcohol group. The photoresist composition of the present invention has high UV transmittance especially at short wavelengths such as 157 nm and 193 nm, and this property makes it useful for lithography at such short wavelengths.

Description

Detailed Description of the Invention

(Cross Reference to Related Application) The present patent application is filed on May 5, 2000 and is pending provisional application No. 60.
/ 201, 961 claims the benefit of priority. The patent application is 2
Application No. 09/71 filed on November 16, 2000, claiming the benefit of priority of provisional application No. 60/166035 filed on November 17, 2000
This is a partial continuation application of No. 4,782. All of these applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates to photoimaging, and in particular to the use of photoresist compositions (positive and / or negative) for imaging during the manufacture of semiconductor devices. Regarding The present invention also relates to a photoresist composition containing a polymer composition having high UV transmittance (especially at a short wavelength such as 157 nm or 193 nm), which is useful as a film-forming resin in a resist composition.

(2. Background) In a method for manufacturing a semiconductor device, an extremely fine feature shape is etched on a substrate surface which is generally a silicon wafer. This feature is formed on the substrate by electromagnetic radiation that is image-wise impinged on a photoresist composition applied to a silicon wave. The areas of the photoresist composition exposed to electromagnetic radiation are chemically and / or physically altered to form a latent image which upon processing can be imaged for semiconductor device fabrication. Positive photoresist compositions are commonly used in the manufacture of semiconductor devices.

The photoresist composition is applied to a silicon wafer by spin coating. The silicon wafer may be provided with a wide variety of material layers applied in other processing steps. Also, in certain photolithographic processing steps, a hard mask layer, typically silicon dioxide or silicon nitride, may be formed on the silicon wafer as applied underneath the photoresist composition layer. In addition, an antireflective layer (ARC) may be provided by a coating process underneath the photoresist composition layer (this is commonly referred to as the bottom antireflective layer (BARC)) or over the photoresist composition layer. (Generally referred to as a top antireflective layer (TARC)). Generally, the thickness of the resist layer is sufficient to withstand the dry chemical etch process used to transfer the pattern to the silicon wafer.

Various polymer products for photoresist compositions are available from Introduc
Ion to Microlithography, Second Edition L.I. F. Thom
pson, C.I. G. Willson and M.M. J. Bowden, Ameri
can Chemical Society, Washington, DC, 1
994.

Photoresist compositions typically include a film forming polymer that may be a photoactive and photosensitive composition containing one or more photoactive components. Thompso
Upon exposure to electromagnetic radiation (such as UV light), the photoactive component may have a rheological state, solubility, surface characteristics, refractive index, color, electromagnetic properties, or photo-sensitivity, as described in the publications of N et al. It acts in a manner that changes other physical or chemical properties of the resist composition.

The lower the wavelength of the ultraviolet light used, the higher the resolution (the lower resolution limit). 365 nm is one of the currently established imaging processes for fabricating semiconductor devices
There is UV (I-line) lithography. The feature formed by this process has a resolution limit of about 0.35 to 0.30 microns. Known lithographic photoresist compositions using a wavelength of 365 nm are made from diazonaphthoquinone as a dissolution inhibitor and a novolac polymer. It has been clarified that the resolution limit is about 0.35 to 0.13 micron in the deep UV lithography of 248 nm. Well known photoresist compositions used in this process are made from p-hydroxystyrene polymers. To form an ultra-fine featured shape,
Attention is directed to lithographic processes that use shorter wavelength electromagnetic radiation. This is because if a low wavelength such as deep ultraviolet (wavelength less than 300 nm), vacuum ultraviolet (wavelength less than 200 nm) or extreme ultraviolet (wavelength less than 30 nm) is used, the resolution becomes higher. However, at wavelengths below 193 nm, it has been found that the photoresist compositions known for 365 nm and 248 nm have insufficient transparency.

One of the significant problems encountered in developing polymers for use in photoresist compositions that are imaged at low wavelengths such as 157 nm is the lack of transparency at such low wavelengths. In order to form an image with well-defined vertical sidewalls, which is important in achieving high resolution and minimizing defects, the transparency requirement in the photoresist composition is about 20% of the incident light. Should generally be less than about 40% through the resist layer in the thickness direction. Polymers lacking transparency absorb too much light, resulting in unacceptable images with poor resolution and too many defects.

In photolithography at a shorter wavelength, the resolution limit at 193 nm is about 0.18.
Since a very fine feature shape having a low resolution limit such as .about.0.12 micron and 157 nm of about 0.07 micron can be obtained, a photoresist composition that is sufficiently transparent even in these short wavelength regions is required.

Suitable photoresists used at 193 nm or less, especially 157 nm, which not only have high transparency at these short wavelengths, but also have good other important properties such as plasma etching resistance, developability and adhesion properties. There is a demand for compositions.

DISCLOSURE OF THE INVENTION (a) In one embodiment, the present invention is a photoresist composition comprising: (a) a polymer, (i) vinyl ether, and the following structure: R ₁ ) (R ₂ ) ═C (R ₃ ) O—R [wherein R ₁ , R ₂ and R ₃ are independently a hydrogen atom or an alkyl group having 1 to about 3 carbon atoms. R is a substituted or unsubstituted hydrocarbon group containing from 1 to about 20 carbon atoms, and where R is a substituted hydrocarbon group, is typically a fluorine, chlorine, bromine or oxygen atom. Including at least one], and a first repeating unit derived from at least one ethylenically unsaturated compound, and (ii) the following structure: (H) (R ₄ ) C = C (R ₅ ) (CN) [wherein, R ₄ is a hydrogen atom or a cyano group R ₅ represents a hydrogen atom, an alkyl group or CO ₂ R ₆ group having a carbon atom in the range of 1 to about 8 (in the formula, alkyl having R ₆ carbon atoms to about 8 ranging from hydrogen atom or a A polymer having a second repeating unit derived from at least one ethylenically unsaturated compound having a group of: (iii) an acidic group or a protected acidic group, and ( b) It relates to a photoresist composition comprising at least one photoactive component.

In another embodiment, the invention is a step of (A) forming a layer comprising a photoresist composition on a substrate, wherein the photoresist composition is (a) a polymer, i) containing vinyl ether and having the following structure: C (R ₁ ) (R ₂ ) ═C (R ₃ ) O—R [wherein R ₁ , R ₂ and R ₃ are independently a hydrogen atom or 1 An alkyl group having about 3 carbon atoms, R is a substituted or unsubstituted hydrocarbon group containing 1 to about 20 carbon atoms, and when R is a substituted hydrocarbon group, , Generally containing at least one of a fluorine, chlorine, bromine or oxygen atom] and having at least one ethylenically unsaturated compound, (ii) the structure of: _{(R 4) C = C (} R 5) (CN) [ formula , R ₄ is a hydrogen atom or a cyano group, R ₅ is a hydrogen atom, an alkyl group or CO ₂ R ₆ group having from 1 carbon atom to about 8 range (in the formula, R ₆ is a hydrogen atom or a A repeating unit derived from at least one ethylenically unsaturated compound having an alkyl group having from 8 to about 8 carbon atoms), and (iii) an acidic group or a protected acidic group. A polymer comprising: a group, (b) at least one photoactive component, and (c) a solvent, and (B) drying the photoresist composition to substantially remove the solvent, thereby Forming a layer containing a photoresist composition on a substrate.

In view of some specific embodiments of the photoresist compositions and related methods of the present invention, a polymer comprising a first repeat unit and a second repeat unit has a (film thickness) 1 It is a component of a photoresist composition that can have an optical absorbance per micron of less than 5.0 μm ⁻¹ at a wavelength of 157 nm.

We have found that polymers of nitrile-containing compounds and fluoroalcohols provide polymers that are useful for use in photoresist compositions. The inventors have also found that the vinyl ether moiety contained in such a polymer increases the yield of the polymer.

(Detailed Description of the Invention) The characteristics of the polymer of the present invention (and the photoresist composition comprising this polymer) are obtained by cooperatively combining the first repeating unit, the second repeating unit and the acidic group. Is one of.

Another property of this polymer is that it does not deleteriously absorb vacuum and far UV wavelengths of the electromagnetic spectrum.

(First Repeating Unit) The photoresist composition of the present invention in one embodiment contains vinyl ether and has the following structure: C (R ₁ ) (R ₂ ) ═C (R ₃ ) O—R (In the formula, R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to about 3 carbon atoms, and preferably R ₁ , R ₂ and R ₃ are hydrogen atoms. Is derived from at least one ethylenically unsaturated compound having
A polymer containing a first repeat unit is included. High yields have been achieved when R ₁ , R ₂ and R ₃ are hydrogen. R is a hydrocarbon group containing 1 to about 20 carbon atoms, which may contain one or more heteroatom substituents.
R is generally an alkyl, aryl, aralkyl or alkaryl group containing from 1 to about 20 carbon atoms and optionally containing one or more heteroatom groups. R may be linear or branched. Heteroatoms can be fluorine, chlorine, bromine or oxygen. When the heteroatom substituent of R is oxygen, R
Generally contain hydroxyl groups, C ₁ to C ₆ alkoxy groups, carboxyl groups or carboxyl ester groups. Fluorine is the preferred heteroatom.

The first repeating unit is 2-hydroxyethyl vinyl ether, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, 2-ethylhexyl vinyl ether, isopropyl vinyl ether, CH ₂ ═CO (CH ₂ ) ₂ (CF ₃ ) _m CF ₃ ( Where m is in the range of 0-12), phenyl vinyl ether, benzyl vinyl ether, p-tolyl vinyl ether or 1-adamantyl vinyl ether.

(Second Repeating Unit) The presence of the second repeating unit containing a cyano (CN) group in these polymers results in high optical transparency (that is, optical absorption in vacuum and deep UV). It has been found that etching resistance is improved and etching resistance is improved. The presence of the second repeating unit also provides polar functionality that facilitates developability with low concentrations of acidic groups (fluoroalcohols, esters or aromatic phenolic groups) that would otherwise be required otherwise. can get. In order for the above polymers to have high optical transparency at wavelengths in the vacuum and deep UV regions, the functionality to absorb the electromagnetic spectrum of these regions, such as the aromatic and carbonyl groups in the polymer repeat units, should be minimized. It is desirable to keep it to. The second repeating unit has at least one nitrile group and has the following structure: (H) (R ₄ ) C═C (R ₅ ) (CN) [wherein R ₄ is a hydrogen atom or a cyano group]. A group (CN), R ₅ may be linear or branched and is an alkyl group having from 1 to about 8 carbon atoms,
CO ₂ R ₆ group (in the formula, R ₆ may be a hydrogen atom, or may be linear or branched, and is an alkyl group having 1 to about 8 carbon atoms). Is derived from at least one ethylenically unsaturated compound. This second repeating unit includes acrylonitrile, methacrylonitrile, fumaronitrile (trans-1,2-dicyanoethylene), and maleonitrile (ci).
s-1,2-dicyanoethylene). Acrylonitrile is preferred.

Acidic Group One or more acidic groups that may be present on the first repeating unit and / or the second repeating unit, or on one or more of the above acidic groups present in the polymer. It has been found that any additional repeat unit obtained will provide sufficient acidity in a photoresist composition compatible with developability in basic aqueous media. The acidic group may be any acidic group as long as it does not absorb light at low wavelengths such as vacuum UV and far UV. When the acidic group is a carboxylic acid, a photoresist composition that is useful in terms of developability, but absorbs light in a vacuum UV region and a deep UV region, which is not desirable in a resist used at a low imaging wavelength (157 nm or 193 nm) Attention must be paid to certain carboxylic acids that can lead to

An example of a suitable acidic group is fluoroalcohol. Other examples include specific carboxylic acids such as acrylic acid or methacrylic acid.

When the acidic group is a fluoroalcohol, it is —XCH ₂ C (R _f ) (R _f ′) OH where R _f and R _f ′ are the same and have from 1 to about 10 carbon atoms. Or a different fluoroalkyl group, or when combined, is (CF ₂ ) _n , where n is an integer in the range of 2 to about 10, and X is group VB or VIB (Sarg.
ent Welch Periodic Table, 1979, Sargent Welch Sci
elemental company, Skokey, Illinois), and generally X is an oxygen atom, a sulfur atom, a nitrogen atom or a phosphorus atom). Oxygen is preferred.

The fluoroalkyl group represented by R _f and R _f ′ is a partially fluorinated alkyl group or a completely fluorinated alkyl group (ie, a perfluoroalkyl group) Good. Where R _f and R _f ′ are partially fluorinated alkyl groups, the acidity is such that the hydroxyl protons are substantially removed in a basic medium such as aqueous sodium hydroxide or tetraalkylammonium hydroxide. The degree of fluorination must be sufficient to provide the hydroxyl group (—OH) of the fluoroalcohol group. This is because the hydroxyl group usually has a pK _a value of about 1.
It means that there is sufficient fluorine substitution in the fluorinated alkyl group of the fluoroalcohol group to give a pKa value of 1 or less, preferably about 4 to about 11.

The groups represented by R _f and R _f ′ may be linear or branched,
They may be combined to form (CF ₂ ) _n , where n is from 2 to about 10. The expression "unioned" means that R _f and R _f'are not together in a separate and independent fluorinated alkyl group, but when taken together form a ring structure as shown below. Means

[0025]

[Chemical 1]

More preferably, R _f and R _f ′ are independently a perfluoroalkyl group having 1 to 5 carbon atoms, most preferably both R _f and R _f ′ are trifluoromethyl ( CF ₃ ) group.

In the case of a fluoropolymer in which the acidic groups form part of the first repeat unit, this can be represented by Structural Formula I below. C (R ₁ ) (R ₂ ) = C (R ₃ ) -OAC (R _f ) (R _f ′) OH (wherein R _f and R _f ′ and R ₁ , R ₂ and R ₃ Is as defined above, and A is at least one atom or group of atoms connecting the vinyl ether to the carbon atom of the fluoroalcohol group via an oxygen atom). Generally, A is an alkylene group having 1 to about 12 carbon atoms, which may be branched or straight chain. A contains a heteroatom such as oxygen, sulfur, fluorine or nitrogen which may be in the alkylene chain or may be a side group of the alkyl chain as a substituent such as a perfluoro group. May be. A is an alicyclic group containing 3 to about 10 carbon atoms, such as cyclohexyl or norbornyl, or an aromatic group containing 6 to about 14 carbon atoms, such as phenyl or naphthyl. May be A may also be a substituted alicyclic group. In this case, A contains a heteroatom such as oxygen, sulfur, fluorine or nitrogen, which heteroatom may be in the alicyclic ring or may be a side group to the alicyclic ring as a substituent such as a perfluoro group. It may be a group. -C Examples of perfluoro group (CF _{3) 2} - is. Some examples of first repeat units falling within the scope of Structural Formula I are described below.

CH ₂ ═CHOCH ₂ CH ₂ OCH ₂ C (CF ₃ ) ₂ OH CH ₂ ═CHO (CH ₂ ) ₄ OCH ₂ C (CF ₃ ) ₂ OH

When the first repeating unit contains a fluoroalcohol as an acidic group, the fluoroalcohol is generally in the range of about 10 to about 60 mole percent and the second repeating unit is generally about 20 to about 80 moles. It is a percentage range. More generally, the fluoroalcohol will be in the range of 45 mole percent or less, preferably 30 mole percent or less, with the relatively small amount of nitrile groups in the second repeating unit making up the remainder of the polymer. If the acidic group is a fluoroalcohol, this is 1,1
-Bis (trifluoromethyl) ethylene oxide, 1,1,1-trifluoro-
It can be derived from 4-methyl-2- (trifluoromethyl) -4-penten-1-ol.

The concentration of acidic groups such as fluoroalcohol groups can be determined depending on the developability of the photoresist composition in an aqueous base solution (eg, a standard 0.262N TMAH solution). If the concentration of acidic groups is high, a photoresist composition that does not function as a resist will be obtained, that is, the photoresist composition will be substantially dissolved during the development step and a useful image cannot be formed. Sometimes. The concentration of the acidic group can be changed depending on the structure of the portion having the acidic group, what the other monomer is and how much the concentration thereof is, and other parameters of the polymer such as the molecular weight. When the fluoroalcohol, which has been found to have insufficient solubility in an aqueous base medium, is an acidic group, some examples of this polymer include AN / IBFA (76/24) and AN / IBFA / NB. (61/21
/ 18) [(wherein AN is acrylonitrile, IBFA is 1,1-trifluoro-4-methyl-2- (trifluoromethyl) -4-penten-2-ol, NB
Is norbornene].

(Protected acidic group) The acidic group may be protected. For purposes of the present invention, "protected acidic group" means a functional group which, when deprotected, imparts a free acid functionality which enhances solubility, swelling or dispersibility in an aqueous environment.

The proportion of repeating units in the polymer containing protected acidic groups is from about 1 to about 70.
It may be in the range of mole percent, preferably in the range of about 5 to about 55 mole percent, and more preferably in the range of about 10 to about 45 mole percent.

Non-limiting examples of protected acidic groups include carboxylic acids and fluoroalcohols. At least one fluoroalcohol group of the polymer or other acidic group of the polymer (such as a carboxylic acid group) may be protected. An additive composition containing protected acidic groups may be incorporated into the photoresist composition. When such additives are included, the acidic groups of the polymer may not be protected at all, or some or all of them may be protected. For example, the photoresist composition is
It may contain at least one member selected from the group consisting of a carboxylic acid, a fluoroalcohol, a protected fluoroalcohol, and a protected carboxylic acid.

When the polymer contains one or more protected acidic groups, the polymer has a hydrophilic acidity due to the catalytic reaction of the acid or base photolytically generated from the photoactive compound (PAC). Generate a group. The protected acidic group is an acid labile one such that when a photoacid or photobase is generated during imagewise exposure, this acid or base catalyzes deprotection and generation of a hydrophilic acidic group. May be base-unstable. It is also possible to deprotect by heating the photoresist composition.

The deprotected acidic group provides a free acid functionality that improves the solubility, swelling, dispersibility of the polymer to which the acidic group is attached in an aqueous environment, or a combination thereof.

An example of a component having a protected acidic group that provides an acidic group upon exposure to a photogenerated acid is A) capable of forming or translocating a tertiary cation. Ester, B) lactone ester, C) acetal ester,
D) β-cyclic ketone ester, E) α-cyclic ether ester, F) MEEMA
(Methoxyethoxyethylmethacrylate) and other esters that are easily hydrolyzed by the participation of adjacent groups, G) carbonates formed from fluorinated alcohols and tertiary aliphatic alcohols. Among the examples in class A) are t-butyl ester, 2-methyl-2-adamantyl ester, isobornyl ester. Among the specific examples in category B) are γ-butyrolactone-3-
Yl, γ-butyrolactone-2-yl, lactone mevalonate, 3-methyl-γ-
Butyrolactone-3-yl, 3-tetrahydrofuranyl, 3-oxocyclohexyl. Among the specific examples in category C) are 2-tetrahydropyranyl, 2
-Tetrahydrofuranyl, 2,3-propylene carbonate-1-yl.
Another example of class C) is the various esters obtained by addition of vinyl ethers, such as, for example, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, acetoxyethoxyethyl vinyl ether.

Examples of protective groups for fluorinated alcohols that produce fluorinated alcohols as hydrophilic groups upon exposure to photogenerated acids or bases include t-butoxycarbonyl (t-BOC), t-butyl ether, 3 -Cyclohexenyl ether, but not limited thereto. Any of these protected acidic groups can be used in combination with the fluorine alcohol group of the present invention to form a protected acidic fluorine alcohol group. The (protected or unprotected) fluoroalcohol group of the present invention may be used alone or (unprotected).
It may be used in combination with one or more other acid groups such as carboxylic acid groups or t-butyl esters of (protected) carboxylic acids.

In the present invention, but not always, the component having a protected acid group is often a repeating unit having a protected acid group introduced into the polymer. Often, protected acid groups are present in one or more monomers that are polymerized to form a polymer. Alternatively, it is possible to form the polymer by polymerization with acid-containing monomers and subsequently convert the acid by suitable means into a partially or fully protected acidic group. As one specific example, P (AN / VE-F-OH / tBA
) That is, in the polymer reaction product of acrylonitrile, vinyloxyethyloxyhexafluoroalcohol adduct and t-butyl acrylate, a t-butyl ester protected acidic group can be mentioned.

When the first repeating unit contains a protected acid group, this first repeating unit can be, for example, 1,1-bis (trifluoromethyl) ethylene oxide and 2-hydroxyethyl vinyl ether or 4-hydroxy. It can be a reaction product with any of the butyl vinyl ethers, which can subsequently be reacted with reagents to produce protected acid groups. An example of a reagent for producing a protected acid group (eg, protected fluoroalcohol) is chloromethyl methyl ether. Another example of a reagent for generating the protected acid groups are di -t- butyl dicarbonate _{(O (CO 2 C (CH} 3) 3). In this case, the protected group is created Is t-butoxycarbonyl (t-BOC), as described above, the alkyl group contains from 1 to about 10 carbon atoms and is linear or branched;
Alkyl-substituted acrylates or alkyl-substituted methacrylates such as secondary butyl acrylate and tertiary butyl methacrylate, or other acids protected with 4-tert-butoxycarbonyloxystyrene or 4-tert-butoxycarbonyloxy-α-methylstyrene. It is also possible to introduce. Generally, the alkyl group is a tertiary alkyl group.

In another embodiment, the polymers of this invention can contain one or more aliphatic polycyclic groups. In this embodiment, the proportion of repeating units in the polymer containing aliphatic polycyclic groups can range from about 1 to about 70 mole percent, preferably about 10 to about 55 mole percent, more preferably about. It can be from 20 to about 45 mole percent.

The polymers of the present invention can contain other functional groups other than those specifically mentioned herein, as long as the polymer is substantially free of aromatic groups. . Aromatic groups impair transparency and result in photoresist compositions that absorb too strongly in regions suitable for use in photoresist compositions that are imaged at wavelengths in the deep UV and extreme UV. It is clear.

In many embodiments according to the present invention, the polymer has an optical absorbance per micron of less than 5.0 μm ⁻¹ at a wavelength of 157 nm, preferably 4.0 μm at this wavelength.
It is less than m ⁻¹ , more preferably less than 3.5 μm ⁻¹ at this wavelength.

Branched Polymer In some embodiments of the present invention, the polymer is a branched chain having one or more side chain segments chemically attached along a linear backbone segment. It is a polymer. The branched polymer is one that can be formed during free radical addition polymerization of at least one ethylenically unsaturated macromer component and at least one ethylenically unsaturated comonomer. This ethylenically unsaturated macromer has a number average molecular weight (M _n ) of several hundred to about 40,000, and the number average molecular weight (M _n ) of the linear main chain segment obtained by polymerizing the same is about 2,000 to about 500,000. The weight ratio of the linear main chain segment to the side chain segment is in the range of about 50/1 to about 1/10, preferably about 80/20 to about 60/4.
The range is 0. Preferably, the macromer component has a number average molecular weight (M _n ) of about 50.
0 to about 40,000, more preferably about 1,000 to about 15,000.
Is. Generally, such ethylenically unsaturated macromer components will comprise from about 2 to about 500 monomer units used in the formation of the macromer component, preferably about 30.
Often have a number average molecular weight ( _Mn ) corresponding to where there are from about to about 200 monomer units, most preferably from about 10 to about 50 monomer units.

In a preferred embodiment, the branched polymer contains from about 25 wt% to about 100 wt% compatibilizing groups, ie, groups that enhance compatibility with the photoacid generator, and preferably from about 50 wt%. About 100% by weight, more preferably about 75% to about 100% by weight. Suitable compatibilizing groups for ionic photoacid generators include, but are not limited to, both non-hydrophilic polar groups and hydrophilic polar groups. Suitable non-hydrophilic polar group, a cyano (-CN) and nitro (-NO ₂₎ and the like, but is not limited thereto. Suitable hydrophilic polar groups include proton groups such as hydroxy (OH), amino (NH ₂ ), ammonium, amide, imide, urethane, ureido or mercapto, or carboxylic acid (CO ₂
H) include, but are not limited to, sulfonic acid, sulfinic acid, phosphoric acid or phosphoric acid or salts thereof. Preferably, the compatibilizing group is present on the side chain segment (s).

Preferably, the protected acidic groups present in the branched polymer are exposed after exposure to UV or other actinic radiation and post-exposure baking (ie during deprotection).
It produces a fluoroalcohol group or a carboxylic acid group.

In the case of a branched chain system containing a protected acidic group, the protected acidic group is treated with the ethylenically unsaturated macromer, the side chain segment of the resulting branched polymer, or the branched polymer. It can be introduced in both the backbone or side chain segment and the backbone. The protected acidic group can be introduced at any time during or after the formation of the branched polymer.

When a branched polymer is present in the photosensitive composition of the present invention, the branched polymer generally contains from about 3% to about 40% by weight of monomer units containing protected acidic groups. %, Preferably about 5% to about 50%, more preferably about 5% to about 20%. The side chain segments of such preferred branched polymers generally contain from 35% to 100% protected acid groups. When such a branched polymer is completely deprotected (all protected acidic groups are converted to free acidic groups), the acid number is about 20 to about 500, preferably about 30 to about 330, More preferably it will be from about 30 to about 130, likewise the acid number of the ethylenically unsaturated macromer component will preferably be from about 20 to about 650, more preferably about 90.
To about 300, the majority of the free acidic groups are contained in the side chain segment.

In a specific embodiment, the branched polymer comprises one or more side chain segments chemically attached along a linear backbone segment, wherein the branched polymer is Has a number average molecular weight (M _n ) of about 500 to about 40,000. The branched polymer contains at least 0.5% by weight of side chain segments. Side chain segments, also known as polymer arms, are generally randomly distributed along the linear backbone segment. The “polymer arm” or side chain segment is
Polymers or oligomers having at least two repeating monomer units linked to a linear backbone segment by covalent bonds. Side chain segments or polymer arms can be introduced into the branched polymer as a macromer component during the macromer and comonomer addition polymerization process. For purposes of this invention, a "macromer" is a polymer, copolymer or oligomer containing terminal ethylenically unsaturated polymerizable groups and having a molecular weight ranging from a few hundred to about 40,000. Preferably, the macromer is a linear polymer or linear copolymer endcapped with ethylenic groups. Generally, one branched polymer has 1
Copolymer having one or more polymer arms, preferably at least two polymer arms, used in the polymerization process at about 0.5% by weight
To about 80% by weight, preferably about 5% to about 50% by weight, of the monomer component is a macromer. Generally, the comonomer component used with the macromer in the polymerization process also contains a single ethylenic group capable of copolymerizing with the ethylenically unsaturated macromer.

One or more protected acidic groups are attached to the ethylenically unsaturated macromer and side chain segments of the resulting branched polymer and / or the main chain of this branched polymer. May be.

(Polymerization Process) The polymer of the present invention may be synthesized by any known polymerization process.

Solution polymerization is one of the general polymerization processes. Any of the commonly used organic solvents known to those skilled in the art may be used as the polymerization solvent. The solvent used for the polymerization depends on the composition of the polymer. However, the present inventors have found that 2-butanone and tetrahydrofuran are useful solvents.

If the polymerization is carried out under atmospheric pressure and reflux conditions, the temperature of the polymerization is usually about 45.
To about 150 ° C, and generally about 50 to about 85 ° C. When the polymerization is carried out under pressure, the polymerization temperature is usually about 0 to about 2
It can be in the range of 00 ° C, generally about 50 to about 150 ° C. Alternatively, the above polymers can be synthesized by (a) emulsion or (b) suspension (bead) polymerization methods. Using a polymerization initiator such as 2,4-dimethyl-2,2′-azobis (pentanenitrile) or 2,2′-azobis (2-methylbutyronitrile) or 2,2′-azobisisobutyronitrile May be. Such polymerization initiators are commercially available from Aldrich Chemical Company, Milwaukee, WI.

To produce the above-mentioned branched polymer, it is preferable to carry out addition polymerization using a macromer and at least one ethylenically unsaturated monomer, but either addition polymerization or polycondensation reaction is utilized. It is also possible to use other known methods for preparing branched polymers by Further, the use of preformed backbone and / or side chain segments can also be used in the present invention.

Side chain segments attached to a linear backbone segment are described in US Pat. No. 4,680,3
It is possible to derive from macromers having ethylenic unsaturation at the terminal position, prepared by methods well known in the art, such as the summary of the invention in No. 52 and No. 4,694,054.

The branched polymer can be prepared by a conventional addition polymerization process. One or more compatible ethylenically unsaturated macromer components, one or more conventional compatible ethylenically unsaturated macromer components, one or more conventional compatible ethylenically unsaturated monomer components (singular Or a plurality of), branched or comb polymers can be prepared. Preferred addition-polymerizable ethylenically unsaturated monomer components include acrylonitrile, methacrylonitrile, fumaronitrile, maleonitrile, protected or unprotected unsaturated fluoroalcohols or protected or unprotected unsaturated carboxylic acids.

(Photoactive Component (PAC)) The composition of the present invention generally contains at least one photoactive component (PAC) which is a compound that gives an acid or a base upon exposure to actinic radiation. If acids are produced on exposure to actinic radiation, PACs are called photoacid generators (PAGs). If a base is produced upon exposure to actinic radiation, PAC is called a photobase generator (PBG).

Photoacid generators suitable for the present invention include, but are not limited to, hydroxamic acid esters such as 1) sulfonium salts (structure I), 2) iodonium salts (structure II), 3) structure III. It is not something that will be done.

[0058]

[Chemical 2]

In Structures I-II, R _a , R _b and R _c are independently substituted or unsubstituted aryl or substituted or unsubstituted C ₁ -C ₂₀ alkylaryl (aralkyl). Representative aryl groups include, but are not limited to, phenyl and naphthyl. Suitable substituents include hydroxyl (-OH)
, And C ₁ -C ₂₀ alkyloxy (eg, C ₁₀ H ₂₁ O), but are not limited thereto. The anion X- in Structures I-II is Sb
F _6- (hexafluoroantimonate), CF ₃ SO _3- (trifluoromethyl sulfonate = triflate), C ₄ F ₉ SO _3- (perfluorobutyl sulfonate), but not limited thereto. It is not something that will be done.

Dissolution Inhibitors and Additives Various dissolution inhibitors can be utilized in the present invention. Ideally, deep U
Dissolution inhibitors (DI) for V resists and vacuum UV resists (eg, 157 nm or 193 nm resists) must meet multiple needs, including dissolution inhibition, plasma etch resistance and adhesion behavior of resist compositions. I won't. Some dissolution inhibiting compounds also function as plasticizers in resist compositions. In general, dissolution inhibitors are included in photoresist compositions to aid the development process. Good dissolution inhibitors are those that prevent unexposed areas of the layer containing the photoresist composition from dissolving in the positive working system during the development process. Useful dissolution inhibitors may function as plasticizers, which results in a layer of photoresist composition that is less brittle and resists cracking. Thus, the addition of the dissolution inhibitor can improve the contrast, the plasma etching resistance, and the adhesion behavior of the photoresist composition.

Esters of various bile salts (ie, cholate esters) are particularly useful as DI in the compositions of the present invention. Reichman in 1983
Starting with studies by is et al., esters of bile salts are known to be effective dissolution inhibitors for deep UV resists (E. Reichmanis et al., “
The Effect of Substitutes on the Ph
otosensitivity of 2-Nitrobenzyl Este
r Deep UV Resists ", J. Am. Electrochem. Soc
． 1983, 130, 1433-1437). Available from natural sources,
Esters of bile salts as DI for a number of reasons, including their high alicyclic carbon content, especially their transmission in the deep UV and vacuum UV regions of the electromagnetic spectrum (eg, they are generally very well transmitted at 193 nm). Kinds are a particularly attractive option. In addition, bile salt esters are attractive choices in DI as they can be designed to have a wide range of compatibility, from hydrophobic to hydrophilic, depending on hydroxyl substitution and functionalization.

Representative bile acids and bile acid derivatives suitable as additives and / or dissolution inhibitors for the present invention include, but are not limited to, those listed below. Cholic acid (IV), deoxycholic acid (V), lithocholic acid (VI), t-butyl deoxycholate (VII), t-butyl lithocholic acid (
VIII), t-butyl-3-α-acetyllithocholic acid (IX). Compound VI
Bile acid esters including I to IX are preferred dissolution inhibitors in the present invention.

[0063]

[Chemical 3]

Embodiments of Components for Negative Photoresist Composition Some of the embodiments of the present invention are negative photoresist compositions. These negative-acting photoresist compositions include at least one binder polymer consisting of acid labile groups and at least one photoactive component that provides a photogenerated acid. By exposing the resist imagewise, an acid is generated, which changes the acid labile group to a polar group (
For example, ester groups (less polar) are converted to acidic groups (more polar). Development with organic solvents or critical fluids (moderate to low polarity) yields a negative tone system in which exposed areas remain and unexposed areas are removed.

A variety of different cross-linking agents can be utilized in the negative-working compositions of the present invention as needed or as an optional photoactive component (s). (While embodiments involving insolubilization in the developer solution as a result of crosslinking require a crosslinking agent,
It is optional in the preferred embodiment where there is insolubilization in the developer solution because polar groups are formed in the exposed areas that are insoluble in medium or low polarity organic solvents and critical fluids).

(Other Components) The composition of the present invention may contain other components. Examples of other components that can be added include resolution improvers, adhesion promoters, residue reducers, coating aids, surfactants, plasticizers, and T _{g (} glass transition temperature) regulators. It is not limited to.

(Process Steps) (Imagewise Exposure) The photoresist composition of the present invention has an ultraviolet region of the electromagnetic spectrum, particularly ≦ 36.
It is sensitive to a wavelength of 5 nm. Imagewise exposure of the resist composition of the present invention is 3
It can be done at many different UV wavelengths including, but not limited to, 65 nm, 248 nm, 193 nm, 157 nm and even lower wavelengths. The imagewise exposure is preferably carried out with ultraviolet light having a wavelength of 248 nm, 193 nm, 157 nm or lower, more preferably 193 nm, 157 nm or lower. Most preferably, it is performed with low wavelength ultraviolet light. The imagewise exposure may be performed digitally with a laser or a device equivalent thereto, or non-digitally with a photomask. A laser device suitable for imaging the composition of the present invention is 193n
Examples include, but are not limited to, an argon-fluorine excimer laser having a UV output at m, a krypton-fluorine excimer laser having a UV output at 248 nm, and a fluorine (F2) laser having an output at 157 nm. Argon Fluorine (A
Photolithography with an exposure wavelength of 193 nm obtained with an rF) excimer laser is one of the leading candidates for future microelectronics manufacturing with 0.18 and 0.13 micron design rules. Photolithography using an exposure wavelength of 157 nm obtained with a fluorine excimer laser is 0.1
It is one of the leading candidates in microelectronics manufacturing using 0 and 0.07 micron design rules.

(Development) The polymer in the resist composition of the present invention contains sufficient acidic groups for development following imagewise exposure to UV light. The presence of an acidic group or a protected acidic group enables aqueous development to be carried out using a basic developing solution such as a sodium hydroxide solution, a potassium hydroxide solution or a tetramethylammonium hydroxide solution.

When the aqueous processable photoresist composition is generally coated or otherwise formed on a substrate and imagewise exposed to UV light, the polymer of the photoresist composition is protected with protected acidic groups or protected. UV contains enough acidic groups
Upon exposure to light, the exposed areas of the layer containing the photoresist composition become developable in a basic solution.

When a positive working layer comprising a photoresist composition is used, the photoresist composition is such that the areas exposed to UV radiation are removed during development, while the unexposed areas are removed during development.
． Such as a completely aqueous solution containing 262N tetramethylammonium hydroxide (usually less than 120 seconds development at 25 ° C) or 1% by weight sodium carbonate (usually less than 2 minutes or 2 minutes development at 30 ° C). It is virtually unaffected by the alkaline aqueous solution.

In the case of a negative working layer comprising a photoresist composition, the photoresist composition is UV
The portions that have not been exposed to radiation are removed during development, but the exposed portions are substantially unaffected during development with either the critical fluid or the organic solvent.

As used herein, a critical fluid is one or more substances that have been heated to temperatures near or above their critical temperature and compressed to pressures near or above their critical pressure. The critical fluid in the present invention has a temperature higher than at least 15 ° C. below the critical temperature of the fluid, and at least higher than 5 atm below the critical pressure of the fluid. Carbon dioxide can be used as the critical fluid of the present invention. Further, various organic solvents can be used in the developer of the present invention. These solvents include, but are not limited to, halogenated solvents and non-halogenated solvents. Halogenated solvents are preferred and fluorinated solvents are even more preferred.

[0073]

[Table 1]

[0074]

[Table 2]

[0075]

[Table 3]

EXAMPLES Unless otherwise stated, all temperatures are degrees Celsius, all mass measurements are in grams, and all percentages are percentages by weight except monomer percentages. Unless otherwise stated, all parts and percentages of repeating units derived from the monomers present in the polymers of this invention are expressed in mole parts and mole percent. The molecular weights obtained were all GPC using polystyrene standards.
It is due to. The proportion of comonomer in the polymers used in the examples is between 5 and 5.
Accurate within 10 percent and determined by C-13 NMR spectroscopy.

As used herein, the expression “clearing dose” is the minimum exposure energy density (eg, mJ / cm ² ) at which a particular photoresist composition can be developed after exposure.

(Measurement of Transparency) Two film samples having different thicknesses were prepared from a specific polymer, the respective thicknesses were determined, and the absorption coefficient value at 157 nm was determined using the following general procedure.

First, Brewer Cee (Laura, MO), Spincoater / H
A sample was spin-coated on a silicon wafer with an optlate model number 100CB. a) Two to four silicon wafers were spun at different speeds (eg 2000, 3000, 4000, 6000 rpm) after applying a small amount (several mL) of polymer solution to obtain films with different thickness. Bake this at 120 ° C for 30 minutes,
The residual solvent was removed. Next, Gaertner Scientific
(Chicago, Illinois), L116A Ellipsometer (400-1)
The thickness of the dried film was measured using a range of 200 Å). b) 2 sheets of CaF ₂ substrate (1 inch diameter (2.54 cm) × thickness 0.80 inches (2.03)) were selected to give a reference data file by measuring each. These measurements are based on the 234/302 Monochromator, 632 Deuterium.
McPherson Spectro including a Light Source, 658 photomultiplier tube detector whose output is measured with a Keithley 485 picoammeter.
It was performed using a meter (Chemsford, Mass.). c) Next, two speeds were selected from the silicon wafer data (a) and the sample material was spun onto a CaF ₂ reference substrate (eg 2000 and 4000 rpm) to achieve the desired film thickness. Next, each film and substrate were baked at 120 ° C. for 30 minutes, and then a propagation data file of each sample was collected using a McPherson Spectrometer. The sample file was then adjusted (ie, split) with the reference CaF ₂ file to obtain a transmittance file (ie, sample film on CaF ₂ split with CaF ₂ blank). Next, GRAMS386 and KALEI
The transmittance file was converted to an absorbance file using DAGRAPH software. d) Next, using the absorbance file and the film thickness value obtained in c), the optical absorbance (Abs / micron) value per 1 micron film thickness was obtained as described later in some examples. . The optical absorbance values per micron of the two films for the particular polymer were averaged to give the average value shown for the particular polymer.

Example 1 Preparation of 1,1-bis (trifluoromethyl) ethylene oxide (HFIBO) 15 g of chlorine was bubbled into 50 mL of a solution of NaOCl (NaOH 50 wt.% In 100 mL of water) to -5 to -3. Hexafluoroisobutene CH ₂ ═C (CF ₃ ) ₂ (25 mL, 40 g) was polycondensed in a flask containing the solution, and 0.5 g of a phase transfer catalyst, that is, methyltricaprylylammonium chloride was converted from −2 to +2 It was added with vigorous stirring at ° C. The reaction mixture was maintained at this temperature for 1-1.5 hours.

The resulting reaction mixture was transferred from the reactor into vacuum and cold trap (-78 ° C).
), And distilled, b. p. 42 ° C / 760mmHg liquid 37.5
g (86% yield) was obtained. This was determined to be 1,1-bis (trifluoromethyl) ethylene oxide (1). It was confirmed that the obtained compound (1) had the following structure based on the analytical data obtained as follows.

¹ HNMR: 3.28 (s) ppm ¹⁹ FNMR: 73.34 (s) ppm ¹³ C {H} NMR: 46.75 (s), 54.99 (sept, 37 Hz), 1
26.76 (q, 275) IR (gas, main component): 1404 (s), 1388 (s), 1220 (s), 1
083 (s), 997 (m), 871 (m), 758 (w), 690 (m), 6
The 36 (w) cm ⁻¹ analytical value is the calculated value for C ₄ H ₂ F ₆ O: C, 26.68, H1.12. Found: C, 27.64, H, 1.10.

Example 2 Synthesis of CH ₂ = CHOCH ₂ CH ₂ OCH ₂ C (CF ₃ ) ₂ OH (VE-F-OH) Drying with mechanical stirrer, condenser and additional funnel. The prepared 5-L round bottom flask was flushed with nitrogen and 14.2 g of 95% sodium hydroxide (0
． 59 mol) and 400 mL of anhydrous DMF were charged. The mixture was cooled to 10 ° C. and 41.6 g (0.47 mol) of 2-hydroxyethyl vinyl ether was added dropwise over 1/2 hour. Add an additional 250 mL of DMF,
The mixture was stirred for 1 hour. 1,1-bis (trifluoromethyl) ethylene oxide obtained in Example 1 (hexafluoro-isobutylene epoxide, HFIBO
) (85 g, 0.47 mol) was added over 1 hour at 20-23 ° C.
The resulting suspension was stirred for 22 hours. This was transferred to a one-neck flask, and most of DMF was removed by a rotary evaporator at 0.1 mm and 29 ° C. The residue is water 25
Dissolve in 0 mL and carefully add 10% hydrochloric acid until the pH of the solution is about 8. The oily supernatant that separated was collected, washed with water, and dried over a mixture of anhydrous sodium sulfate and potassium carbonate. The resulting oil was filtered off and the filtrate was distilled from a small amount of anhydrous potassium carbonate on a Kugelrohr apparatus at 0.5 mm and 50-59 ° C to give 89 g (71%) of oil. It was stored on potassium carbonate. ¹ HN
MR (δC ₆ D ₆ ) 3.12 (d, 2H), 3.28 (d, 2H), 3.60 (s, 2)
H), 3.90 (d, 1H), 4.07 (d, 1H), 6.20 (dd, 1H)
. ¹⁹ FNMR (δC ₆ D ₆ ) −76.89 (s). Elemental analysis was performed on another sample prepared in the same manner. _{C 8 H 10 F 6 O 3} : C, 35.83; H, 3.7
6; Calculated for F, 42.51. Found: C, 35.13; H, 3.9.
2; F, 41.40.

Example 3 Synthesis of VE-F-OMOM A round bottom flask equipped with a mechanical stirrer, thermocouple, additional funnel and nitrogen inlet was swept with nitrogen to remove 300 mL anhydrous THF and 95% sodium hydroxide. 1
3.1 g (0.52 mol) was charged. 2-Hydroxyethyl vinyl ether (45.4 g, 0.5 mol) was added dropwise so that the reaction temperature did not exceed 35 ° C. If necessary, another THF was added to the obtained slurry to facilitate stirring. After stirring for 1 hour at ambient temperature (about 20 ° C to about 23 ° C),
The mixture was cooled to about 0 ° C. and HFIBO obtained in Example 1 (93.9 g, 0.
52 mol) was added dropwise. An exotherm up to about 40 ° C was observed and the reaction mixture became a homogeneous solution. This was stirred at room temperature overnight. The solution was cooled to 0 ° C. and chloromethyl methyl ether (41.8 g, 0.52 mol) was added dropwise, an exotherm up to 5 ° C. occurred and a precipitate was formed. The above precipitate containing mixture was stirred at room temperature overnight. The mixture is filtered off and the solids are
It was washed with 100 mL of HF. The combined filtrate and wash was concentrated on a rotary evaporator to an oil which was stirred at 0.13 Torr and 30 ° C. K.
Distilled on ugelrohr. The distillate was then purified by flash chromatography using 9/1 hexane / ethyl acetate for elution. 82.3 g of product (
53%) was isolated as an oil. ¹ HNMR (δCDCl ₃ ) 3.44 (s,
3H), 3.75 (m, 2H), 3.85 (m, 2H), 4.04 (dd, 1H)
), 4.17 (s, 2H), 4.20 (dd, 1H), 5.10 (s, 2H),
6.50 (dd, 1H). ¹⁹ FNMR ^(δCDCl ₃₎ -74.4. Elemental analysis was performed on another sample prepared in the same manner. _{C 10 H 14 F 6 O 4} : C, 38.
47; H, 4.52; F, 36.51. Found: C, 38.
47; H, 4.69; F, 33.92.

Example 4A (Synthesis of P (AN / VE-F-OH) Polymer) An acrylonitrile / vinyloxyethyloxyhexafluoroalcohol adduct copolymer was prepared by the following procedure. The procedure used a 100 mL flask equipped with a thermocouple, a stirrer, a dropping funnel, a reflux condenser, a Dean-Stark trap, and a means for producing a bubble of nitrogen throughout the reaction. .

[0086]   The ingredients and amounts used in this example are listed in the table below.

[0087]

[Table 4]

Vazo®-67 polymerization initiator was dissolved in 1.65 grams of acetonitrile (portion 1) in a container. The remaining ingredients of Portion 1 were added to a 100 mL reaction flask and allowed to reach reflux temperature. Next, the polymerization initiator solution was added all at once to a 100 mL flask. The polymerization initiator vessel was washed with the remaining 0.5 grams of acetonitrile and added to the reaction flask. Vazo (registered trademark) -67
Immediately after adding the polymerization initiator, the monomer of Portion 2 completely dissolved in acetonitrile and Vazo (registered trademark) -52 of Portion 3 completely dissolved in acetonitrile and acrylonitrile were simultaneously supplied at a reflux temperature for 240 minutes. did. After the feeding of portions 2 and 3 was completed, Vazo® 67 polymerization initiator of portion 4 completely dissolved in acetonitrile was added at once. Polymerization was continued at reflux temperature for another 90 minutes. Next, the solvent was volatilized to remove unreacted acrylonitrile, and the volatilized solvent and monomer were collected in a flask containing ethylenediamine. Next, 20 mL of acetonitrile was added and volatilization was performed again to remove a trace amount of acrylonitrile remaining in the polymer. This stripping procedure was repeated two more times by adding 20 mL of acetonitrile to the reaction flask each time. Finally, a large excess of the polymer solution in acetonitrile (
The polymer was precipitated by addition to 250 grams of petroleum ether. The precipitated polymer was filtered off and washed twice with petroleum ether. The wet polymer was dried in vacuum at ambient temperature for 12 hours. In this Example 4A,
The molar composition of the monomers in the feed is 75 parts by mole AN and VE-F-OH25.
It was a molar part. When the concentration of the repeating unit in the polymer in this Example (Polymer 4A) was determined by C-13 NMR, 73.1 parts of those derived from AN and those derived from VE-F-OH were obtained in this Example. Was 26.9 parts. The yield obtained was 15.3 grams (72%). The number average molecular weight of the obtained polymer was 8392 (M _n ), and the polydispersity (D) was 1.88.

Using the above procedure, except for the following changes, the other three types of P (AN
/ VE-F-OH) polymer (Polymer 4B, 4C, 4D) was synthesized.

Example 4B Polymer 4B: 90 parts by mole of AN and 10 parts by mole of VE− as a monomer feedstock.
The procedure of Example 4A was followed except that F-OH was used.

Example 4C Polymer 4C: The procedure of Example 4A was followed except that 82.5 mole parts of AN and 17.5 mole parts of VE-F-OH were used as the monomer feedstock.

Example 4D Polymer 4D: 84 parts by mole of AN and 16 parts by mole of VE as monomer feedstock.
The procedure of Example 4A was followed except that -F-OH was used.

For all four polymers, polymer discrimination (ID), molar composition, polymer yield, number average molecular weight (M _n ) and polydispersity (D), optical per micron measured at 157 nm. The absorbance (Abs / μm) (determined in the following section) is listed below.

[0094]

[Table 5]

(Determination of Optical Absorbance Per Micron) Polymer 4D [P (AN / VE-F-OH) (84.7 / 15.3)] was added to 2-
A solution having a solid content of 5% by weight dissolved in heptanone was spun at 3000 rpm.
spin coating on a CaF ₂ substrate at m to form a 678 Å thick polymer film, then spin coating on a CaF ₂ substrate at a spin speed of 5000 rpm.
A 4 angstrom thick polymer film was formed. McPherson Spec
Optical absorbance per micron was determined as described above utilizing VUV absorbance measurement using a trometer. Polymers 4A, 4 except for the following:
A similar coating process was performed for B and 4C.

Polymer 4A: A 674 angstrom film was formed at a spin speed of 5000 rpm, and a 614 angstrom film was formed at a spin speed of 6000 rpm. PGMEA is used as the coating solvent, and the solid content of the coating solution is 5
It was set to% by weight.

Polymer 4B: A 660 angstrom film was formed at a spin speed of 2500 rpm, and a 562 angstrom film was formed at 3500 rpm. Cyclohexanone was used as the coating solvent, and the solid content of the coating solution was 3% by weight.

Polymer 4C: A 608 angstrom film was formed at a spin speed of 1500 rpm, and a 476 angstrom film was formed at 2500. PGMEA was used as the coating solvent, and the solid content of the coating solution was 3% by weight.

The optical absorbance per micron at 157 nm of the film obtained from polymer 4D (AN / VE-F-OH) (84.7 / 15.3) was determined in reciprocal units of micron. It was as follows. 2.61 / micron for 678 Å thick film, 2.64 for 534 Å thick film, average 2.
62 / micron.

Similarly, for Polymers 4A, 4B and 4C, the average optical absorbance per micron at 157 nm was determined in reciprocal microns and was as follows:

[0101]

[Table 6]

[0102]     (Image formation / Evaluation of lithography)   The following solutions were prepared and magnetically stirred overnight.

[0103]

[Table 7]

Brewer Science Inc. Model No. -100CB combination spin coater / hotplate, "P" type, <100> orientation, diameter 4
Spin coating was performed on an inch (10.2 cm) silicon wafer. L
resist development analyzer (model number -790) from itho Tech Japan
Was used for development. Hexamethyldisilazane (HMDS) primer 6mL
Was adhered and rotated at 1000 rpm for 5 seconds, and then at 3500 rpm for 10 seconds to produce a wafer. Then 0.45 μm PTFE
After filtering with a syringe filter, 3 mL of the above solution was adhered, spun at 3000 rpm for 60 seconds, and baked at 120 ° C. for 60 seconds. An ORIEL Model for 248 nm interference filters that pass approximately 30% of the energy at 248 nm.
The coated wafer was exposed to light obtained through broadband UV light from a -82421 solar simulator (1000 Watts) and imaged at 248 nm. The exposure time was 120 seconds with an attenuation dose of about 80 mJ / cm ² . A wide range of exposure doses was achieved through a mask with 18 positions with different achromatic optical densities. After exposure, the exposed wafer was baked at 120 ° C. for 120 seconds.

Tetramethylammonium hydroxide (TMAH) solution (ONKAnmD-3, 2
． The wafer was developed with a 38% TMAH solution) at 15 second intervals. In this test a positive tone image was formed.

Example 5A P (AN / VE-F-OH / VE-F-OMOM) (78.5 / 12.5 / 9.
0) P (AN / VE-F-OH / VE-F-OMOM), acrylonitrile / vinyloxyethyloxyhexafluoroalcohol adduct / protected vinyloxyethyloxyhexafluoroalcohol adduct polymer, was prepared by the following procedure did. The procedure used a 100 mL flask equipped with a thermocouple, a stirrer, a dropping funnel, a reflux condenser, a Dean-Stark trap, and a means for producing a bubble of nitrogen throughout the reaction. . The ingredients and amounts for this example are listed in the table below.

[0107]

[Table 8]

The Vazo®-67 polymerization initiator was dissolved in 1.225 grams of acetonitrile (portion 1) in a container. The remaining ingredients of Portion 1 were added to a 100 mL reaction flask and allowed to reach reflux temperature. Next, the polymerization initiator solution was added to the flask all at once. The polymerization initiator vessel was washed with the remaining 0.5 grams of acetonitrile and added to the reaction flask. Immediately after adding the Vazo (R) -67 polymerization initiator, the monomer of Portion 2 completely dissolved in acetonitrile and the Vaz of Portion 3 completely dissolved in acetonitrile and acrylonitrile.
o (R) -52 was co-fed at reflux temperature for 240 minutes. After the feeding of portions 2 and 3 was completed, Vazo® 67 polymerization initiator of portion 4 completely dissolved in acetonitrile was added at once. 9 more
Polymerization was continued at reflux temperature for 0 minutes. Next, the solvent was volatilized to remove unreacted acrylonitrile, and the volatilized solvent and monomer were collected in a flask containing ethylenediamine. Next, 18 mL of acetonitrile was added, and volatilization was performed again to remove a trace amount of acrylonitrile remaining in the polymer. This stripping procedure was repeated four more times by adding 18 mL of acetonitrile to the reaction flask each time. Finally, the polymer was precipitated by adding the polymer solution in acetonitrile to a large excess (700 grams) of petroleum ether. The precipitated polymer was filtered off and washed twice with petroleum ether. The wet polymer was dissolved in a solvent mixture containing 30 mL of acetonitrile and 18 mL of acetone. The polymer solution was reprecipitated by addition to 700 grams of petroleum ether, filtered and dried in a vacuum oven for 12 hours at 50 ° C. In this Example 5A, the molar composition of the feedstock monomers was 82.5 parts by mole of AN, VE-F-OH.
Was 10 mol parts and VE-F-OMOM was 7.5 mol parts. When the concentration of the repeating unit in the polymer was determined by C-13 NMR, in this example, 78.5 mol parts of the one derived from AN and 12.12 of the one derived from VE-F-OH were obtained.
5 parts by mol, 9.0 parts by mol derived from VE-F-OMOM. P
(AN / VE-F-OH / VE-F-OMOM) (78.5 / 12.5 / 9.0)
) That is, the yield of the polymer 5A was 66%.

(Example 5B) The monomer feed material was as follows: AN 86 parts by mole, VE-F-OH 12 parts by mole, and VE-
Another P (AN / VE-F-OH / VE-F-OMOM) was prepared using the same procedure as above, except that the amount of monomer was changed to 2 parts by mole of F-OMOM.
That is, polymer 5B was synthesized. P (AN / VE-F-OH / VE-F-OM
The yield of OM), polymer 5B, was 69%.

(Determination of Optical Absorbance Per Micron) Polymer 5B [P (AN / VE-F-OH / VE-F-OMOM) (78.5
/12.5/9.0)] to cyclohexanone / 2-heptanone (weight ratio 1: 1
), Having a solid content of 2.5% by weight, was spin-coated on a CaF ₂ substrate at a spin speed of 2000 rpm to form a polymer film having a thickness of 450 Å and spin-coated on the CaF ₂ substrate at a spin speed of 2500 rpm. A 388 Å thick polymer film was formed. McPherson Spectrom
The optical absorbance per micron was determined as described above using VUV absorbance measurement with an ether.

Using these polymer films, the optical absorbance per micron at 157 nm of polymer 5B was determined in the reciprocal unit of micron, and was as follows. The 450 Å thick film was 2.71 / micron, the 388 Å thick film was 2.84 / micron, and the average of these two values was 2.77 / micron.

(Example 6) (P (AN / VE-F-OH / tBA) (87.6 / 8.4 / 4.0)) (Synthesis of Polymer) P (AN / VE-F-OH / tBA) or acrylonitrile / vinyloxyethyloxyhexafluoroalcohol adduct / tertiary-butyl acrylate terpolymer was prepared by the following procedure. The procedure used a 100 mL flask equipped with a thermocouple, a stirrer, a dropping funnel, a reflux condenser, a Dean-Stark trap, and a means for producing a bubble of nitrogen throughout the reaction. . The ingredients and amounts used in this example are listed in the table below.

[0113]

[Table 9]

Vazo®-67 polymerization initiator was dissolved in 1.225 grams of acetonitrile (portion 1) in a container. The remaining ingredients of Portion 1 were added to a 100 mL reaction flask and allowed to reach reflux temperature. Next, the polymerization initiator solution was added to the flask all at once. The polymerization initiator vessel was washed with the remaining 0.5 grams of acetonitrile and added to the reaction flask. Immediately after adding the Vazo (R) -67 polymerization initiator, the monomer of Portion 2 completely dissolved in acetonitrile and the Vaz of Portion 3 completely dissolved in acetonitrile and acrylonitrile.
o (R) -52 was co-fed at reflux temperature for 240 minutes. After the feeding of portions 2 and 3 was completed, Vazo® 67 polymerization initiator of portion 4 completely dissolved in acetonitrile was added at once. 9 more
Polymerization was continued at reflux temperature for 0 minutes. Next, the solvent was volatilized to remove unreacted acrylonitrile, and the volatilized solvent and monomer were collected in a flask containing ethylenediamine. Next, 18 mL of acetonitrile was added, and volatilization was performed again to remove a trace amount of acrylonitrile remaining in the polymer. This stripping procedure was repeated four more times by adding 18 mL of acetonitrile to the reaction flask each time. Finally, the polymer was precipitated by adding the polymer solution in acetonitrile to a large excess (700 grams) of petroleum ether. The precipitated polymer was filtered off and washed twice with petroleum ether. This oily polymer was dissolved in a solvent mixture containing 50 mL of acetonitrile and 18 mL of acetone. 700
The polymer solution was reprecipitated by addition to grams of petroleum ether, filtered and dried in a vacuum oven for 12 hours at 56 ° C. In this Example 6, the molar composition of the feedstock monomers was 82.5 parts by mole of AN, VE-F-OH.
Was 10 mol parts and VE-F-OMOM was 7.5 mol parts. When the concentration of repeating units in the polymer was determined by C-13 NMR, 87.6 mol parts of the one derived from AN and 8.4 of the one derived from VE-F-OH in this example.
Mole parts, 4.0 mol parts were derived from VE-F-OMOM. The yield of polymer 6 (AN / VE-F-OH / tBA) (87.6 / 8.4 / 4.0) was 74%.

(Determination of Optical Absorbance per Micron) A solution prepared by dissolving this polymer 6 in a 2/1 weight mixture of cyclohexanone and 2-heptanone was spin-coated on a CaF ₂ substrate at a spin speed of 3000 rpm, and 438 angstrom was applied. A polymer film having a thickness of (3.29 Å / mm) is formed, and spin-coated at a spin speed of 3500 rpm to form 399 angstroms (3.38).
Å / mm) thick polymer film was formed. McPherson Spectrom
The optical absorbance per micron was determined as described above using VUV absorbance measurement with an ether.

P (AN / VE-F-OH / tBA at 157 nm with these polymer films.
) (87.6 / 8.4 / 4.0), the optical absorbance per micron is calculated in terms of the reciprocal unit of the micron, which is 3.29 / micron for the 438 Å thick film and 3 for the 399 Å thick film. It is 0.38 / micron. The average of these two determinations is 3.34 / micron.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Mukan Periya Sammy             United States 19810 Delaware             Wilmington Pennington Drive             2623 (72) Inventor Frank Leonardo Shadot The             Third             United States 19806 Delaware             Wilmington Delaware Avenue               2407 F term (reference) 2H025 AA01 AA02 AB16 AC04 AC08                       AD01 AD03 BE00 BE10 BG00                       CB06 CB41 CC17

Claims (10)

[Claims] 1. A photoresist composition comprising: (a) a polymer, (i) vinyl ether, and having the following structure: C (R ₁ ) (R ₂ ) ═C (R ₃ ) O— R [wherein R ₁ , R ₂ and R ₃ are independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R is a substituted group containing 1 to 20 carbon atoms or An unsubstituted hydrocarbon group, where R is a substituted hydrocarbon group, contains at least one fluorine, chlorine, bromine or oxygen atom] and is derived from at least one ethylenically unsaturated compound A first repeating unit, and (ii) the following structure, (H) (R ₄ ) C═C (R ₅ ) (CN) [wherein R ₄ is a hydrogen atom or a cyano group, and R ₅ Is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or O ₂ R ₆ group (wherein, R ₆ is alkyl as radical having a carbon atom in the eight ranging from a hydrogen atom or a 1) having a], is derived from at least one ethylenically unsaturated compound A second repeating unit; (iii) a polymer comprising an acidic group or a protected acidic group; and (b) at least one photoactive component. 2. The acidic group has the following structure: —C (R _f ) (R _f ′) OH, wherein R _f and R _f ′ are the same or containing 1 to 10 carbon atoms. A different fluoroalkyl group or, in combination, is (CF ₂ ) _n , where n is an integer in the range of 2 to 10]. Item 2. The photoresist composition according to item 1. 3. The first repeating unit is 2-hydroxyethyl vinyl ether, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, 2-ethylhexyl vinyl ether, isopropyl vinyl ether, CH ₂ ═.
CO (CH ₂ ) ₂ (CF ₃ ) _m CF ₃ (where m is in the range of 0 to 12), phenyl vinyl ether, benzyl vinyl ether, p-tolyl vinyl ether or 1-adamantyl vinyl ether. Characterized by that
The photoresist composition according to claim 1. 4. The photoresist composition according to claim 3, wherein the second repeating unit is derived from acrylonitrile, methacrylonitrile, fumaronitrile or maleonitrile. 5. The first repeating unit comprises the protected acidic group, and the first repeating unit comprises (a) 1,1-bis (trifluoromethyl) ethylene oxide and (i) 2- Is a reaction product with hydroxyethyl vinyl ether or (ii) 4-hydroxybutyl vinyl ether, which reaction product is later reacted with (i) chloromethyl methyl ether or (ii) t-butyloxycarbonyl Or, (b) a t-alkyl substituted acrylate or a t-alkyl substituted methacrylate, wherein the alkyl group contains from 1 to about 10 carbon atoms. . 6. The photoresist of claim 2, wherein the first repeating unit or the second repeating unit or both contain the acidic group or the protected acidic group. Composition. 7. The first repeating unit has the following structure: CH ₂ ═CH—O—A—C (R _f ) (R _f ′) OH [wherein A is branched or straight chained]. A chained, unsubstituted or substituted alkylene group containing 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic group containing 3 to 10 carbon atoms (A is a substituted alkylene group or an aliphatic group) In the case of cyclic groups, A contains a heteroatom selected from the group consisting of oxygen, sulfur, fluorine and nitrogen), and R _f and R _f ′ contain 1 to 10 carbon atoms. The same or different fluoroalkyl groups or, in combination, a fluoroalcohol having (CF ₂ ) _n (where n is an integer in the range of 2 to 10)] The photoresist composition according to claim 1, wherein: 8. The photoresist composition according to claim 1, wherein the acidic group of the polymer is a carboxylic acid or a fluoroalcohol. 9. The photoresist composition according to claim 2, wherein the fluoroalcohol is protected. 10. A photoimageable substrate comprising: (A) a step of forming a layer containing a photoresist composition on the substrate, wherein the photoresist composition is (a) a polymer. , (I) containing vinyl ether and having the following structure: C (R ₁ ) (R ₂ ) ═C (R ₃ ) O—R [wherein R ₁ , R ₂ and R ₃ are independently a hydrogen atom or An alkyl group having 1 to 3 carbon atoms, R is a substituted or unsubstituted hydrocarbon group containing 1 to 20 carbon atoms, and when R is a substituted hydrocarbon group, , At least one fluorine, chlorine, bromine or oxygen atom], and a repeating unit derived from at least one ethylenically unsaturated compound, (ii) the following structure, (H) (R ₄ ) _{C = C (R 5) (} CN) [ wherein, R ₄ is hydrogen atoms Or a cyano group, R ₅ is a hydrogen atom, a carbon alkyl group or CO ₂ R ₆ group having a carbon atom with 1 to 8 range (in the formula, R ₆ is eight ranging from hydrogen atom or a A polymer having a repeating unit derived from at least one ethylenically unsaturated compound, which is an alkyl group having an atom), and (iii) an acidic group or a protected acidic group, b) at least one photoactive component, and (c) a solvent, and (B) drying the photoresist composition to substantially remove the solvent, thereby containing the photoresist composition. Forming a layer on the substrate; and a photoimageable substrate made by a method comprising: