KR100445920B1 - Photoresist compositions with cyclic olefin polymers and additive - Google Patents

Abstract

Acid-promoted amphoteric photoresist compositions that are imageable and developable with 193 nm radiation to form highly resolved and highly etch resistant photoresist structures include cyclic olefin polymers, photosensitive acid generators, and 193 nm. It is possible using a combination of a bulky hydrophobic additive, a hydrophobic nonsteroidal cycloaliphatic component, a hydrophobic nonsteroidal multi-alicyclic component containing a plurality of acid labile linking groups or a saturated steroid component substantially transparent to. The cyclic olefin polymer is an cyclic olefin having i) acidic and polar functional moieties which enhance solubility in aqueous alkali solution, or cyclic olefin units having polar functional moieties, and (ii) acid labile moieties which inhibit solubility in aqueous alkali solution. Contains units.

Description

Photoresist composition with cyclic olefin polymer and additives {PHOTORESIST COMPOSITIONS WITH CYCLIC OLEFIN POLYMERS AND ADDITIVE}

In the microelectronics industry as well as in other industries including the assembly of microstructures (eg, micromachines, magnetoresistive heads, etc.), there is a continuing need to reduce the size of structural shapes. In the microelectronics industry, there is a desire to reduce the size of microelectronic devices and / or to provide more circuits for a given chip size.

The manufacturability of smaller devices is limited by the ability of photolithographic techniques to reliably resolve smaller shapes and spacing. Optical properties are limited in part by the ability to achieve fine resolution by the wavelength of light (or other radiation) used to produce the lithographic pattern. Thus, there is a continuing trend to use short wavelengths for photolithographic methods. Recently, there is a tendency to shift from the so-called I-line radiation (350 nm) to 248 nm radiation.

In order to further reduce the size, it became necessary to use 193 nm radiation. Unfortunately, photoresist compositions at the heart of recent 248 nm photolithography methods are typically unsuitable for use at shorter wavelengths.

The photoresist composition should have desirable optical properties capable of image resolution at the desired wavelength of radiation, and the photoresist composition also possesses suitable chemical and mechanical properties that can transfer an image from the patterned photoresist to the underlying substrate layer (s). Should have Thus, the exposed positive photoresist at the location to be patterned should allow for adequate degradation reactions (ie, selective degradation of the exposed areas) to obtain the desired photoresist structure. Since the use of aqueous alkaline developers is common in the field of photolithography, it is important to be able to achieve adequate dissolution behavior in such commonly used developer solutions.

The patterned photoresist structure (after development) should sufficiently prevent the transfer of the pattern to the underlying layer (s). Typically, pattern transfer is performed in some form of wet chemical etching or ion etching. The ability of the patterned photoresist layer to withstand pattern transfer etching methods (ie, the etch resistance of the photoresist layer) is an important property of the photoresist composition.

Some photoresist compositions have been designed for the use of 193 nm radiation, but these compositions generally do not provide the true resolution advantage of short wavelength imaging due to the lack of performance in one or more of the areas mentioned above. Accordingly, there is a need for a photoresist composition that is imageable with short wavelength radiation (eg, 193 nm ultraviolet radiation) while retaining good developability and etch resistance.

It is an object of the present invention to provide a photoresist composition which can be imaged by short wavelength radiation while having excellent developability and etch resistance.

The present invention provides a photoresist composition that enables high resolution lithography performance using imaging radiation of 193 nm. The photoresist composition of the present invention has the combination of imageability, developability and anti-etching necessary to deliver the pattern with very high resolution limited only by the wavelength of the imaging radiation. Photoresist compositions of the invention are generally characterized by the presence of cyclic olefin polymers containing a combination of acid labile functional groups and acidic polar functional groups. The photoresist compositions of the present invention are further characterized by the presence of bulky hydrophobic additives that are substantially transparent to 193 nm radiation. The photoresist compositions of the invention also generally comprise (a) a cyclic olefin polymer, and (b) a hydrophobic nonsteroidal cycloaliphatic component, a hydrophobic nonsteroidal poly-alicyclic component containing a plurality of acid labile linkages ("HNMP"). "), Or the presence of a saturated steroid component.

The present invention also provides a photolithography method for creating a photoresist structure using the photoresist composition of the invention, and a method for transferring a pattern to the underlying layer (s) using the photoresist structure. The photolithographic method of the invention is preferably characterized by exposing 193 nm ultraviolet radiation to the position to be patterned. The method of the present invention can resolve shapes less than about 150 nm in size, more preferably less than about 120 nm in size, without the use of a phase shift mask.

In a first aspect, the present invention

(a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a bulky hydrophobic additive substantially transparent to 193 nm radiation,
At this time, the cyclic olefin polymer (a)

(i) cyclic olefin units having acidic and polar functional moieties that enhance solubility in aqueous alkali solutions, and

(ii) a photoresist composition comprising a cyclic olefin unit having an acid labile moiety that inhibits solubility in an aqueous alkali solution.

The cyclic olefin polymer of the invention preferably contains about 5 to 40 mole% of unit (i). The cyclic olefin polymer of the present invention preferably consists essentially of cyclic olefin monomer units; More preferably, they consist essentially of olefin units (i) and olefin units (ii). Bulky hydrophobic additives preferably include alicyclic moieties.

In a second aspect, the present invention

A composition comprising (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal alicyclic component.

In a third aspect, the present invention

A photoresist composition is provided comprising (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal multi-alicyclic (HNMP) component containing a plurality of acid labile linking groups.

In a fourth aspect, the present invention

A photoresist composition comprising (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a saturated steroid component.

In the composition, the cyclic olefin polymer is

(i) cyclic olefin units having polar functional moieties, and

(ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution; Preferably consisting essentially of cyclic olefin monomer units; More preferably, they consist essentially of olefin units (i) and (ii). The olefin unit (i) preferably comprises an acidic polar moiety having _a pK _a of 13 or less.

The hydrophobic nonsteroidal cycloaliphatic component (c) of the second aspect preferably comprises a cycloaliphatic residue of C ₁₀ or higher.

The HNMP component (c) of the third aspect preferably comprises at least two C ₇ or more cycloaliphatic residues. Acid cleavage of the HNMP component preferably forms a plural compound with a compound having plural acid polar functional groups and / or at least one acidic polar group each.

The saturated steroid component (c) of the fourth embodiment is preferably hydrophobic. Preferred saturated steroids are modified litocholates.

In another aspect, the present invention

(a) providing a substrate having a surface layer of a photoresist composition of the invention,

(b) exposing the photoresist layer to radiation at a location to be patterned to expose a portion of the photoresist layer to radiation; And

(c) contacting the photoresist layer with an aqueous alkali developing solution to remove the exposed portions of the photoresist layer to produce a patterned photoresist structure, the method comprising forming a patterned photoresist structure on the substrate. Include.

Preferably, the radiation used in step (b) in the method is 193 nm ultraviolet radiation.

The present invention also includes methods of making conductive, semiconducting, magnetic or insulating structures using patterned photoresist structures containing the compositions of the present invention.

These and other aspects of the invention are discussed in further detail below.

The photoresist composition of the present invention generally contains i) cyclic olefin units having acidic polar functional moieties which enhance solubility in aqueous alkali solution, and (ii) cyclic olefin units having acid labile moieties which inhibit solubility in aqueous alkali solution. It is characterized by the presence of a polymer. The cyclic olefin polymer preferably contains up to 40 mol% cyclic olefin units (i). The composition is further characterized by the presence of a bulky hydrophobic additive that is substantially transparent to 193 nm radiation.

Other photoresist compositions of the invention are generally characterized by the presence of (a) a cyclic olefin polymer, and (b) a hydrophobic nonsteroidal alicyclic component. The cyclic olefin polymer preferably contains (i) cyclic olefin units having polar functional moieties, and (ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

Another photoresist composition of the invention is generally characterized by the presence of (a) a cyclic olefin polymer, and (b) a hydrophobic nonsteroidal poly-alicyclic component containing a plurality of acid labile linking groups. The cyclic olefin polymer preferably contains (i) cyclic olefin units having polar functional moieties, and (ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

The fourth photoresist composition of the present invention is generally characterized by the presence of (a) a cyclic olefin polymer, and (b) a saturated steroid component. The cyclic olefin polymer is characterized by the presence of one or more cyclic olefin monomer units. The cyclic olefin polymer preferably contains i) cyclic olefin units with polar functional moieties and (ii) cyclic olefin units with acid labile moieties that inhibit solubility in aqueous alkali solution.

These photoresist compositions of the present invention have excellent developability and pattern transfer properties and can provide high resolution photolithography patterns using 193 nm radiation.

The invention also includes patterned photoresist structures containing the photoresist composition of the invention, and methods of creating the photoresist structures and using the photoresist structures to form conductive, semiconducting and / or insulating structures.

In a first aspect, the photoresist composition of the invention is generally

(a) a cyclic olefin polymer, (b) a photosensitive component, and (c) a bulky hydrophobic additive substantially transparent to 193 nm radiation, wherein the cyclic olefin polymer (a)

(i) cyclic olefin units having acidic and polar functional moieties that enhance solubility in aqueous alkali solutions, and

(ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

The cyclic olefin unit (i) may be a cyclic olefin monomer unit having an acidic and polar functional group which promotes alkali solubility. Examples of the cyclic olefin monomers include monomers of the following general formula (1).

Where

R ₁ is an acidic polar moiety,

n is zero or some positive integer.

More preferably, the cyclic olefin unit (i) is selected from formulas 2a and 2b.

Where

R ₁ is an acidic polar moiety that enhances solubility in aqueous alkali solution. The acidic polar residues preferably have a pK _a of about 13 or less. Preferred acidic polar moieties contain a polar group selected from the group consisting of carboxyl, sulfonamidyl, fluoroalcohol and other acidic polar groups. Preferred acidic polar moieties are carboxyl groups. If desired, combinations of cyclic olefin units (i) with other acidic polar functional groups can be used.

The cyclic olefin unit (ii) may be a cyclic olefin monomer unit having an acid labile moiety that inhibits solubility in aqueous alkali solution. Examples of the cyclic olefin monomers include monomers of the following general formula (3).

Where

R ₂ is an acid labile protective moiety,

n is zero or some positive integer.

More preferably, the cyclic olefin unit (ii) is selected from the formulas 4a and 4b.

Where

R ₂ is an acid labile protective moiety. Preferred acid labile protecting moieties are selected from the group consisting of tertiary alkyl (or cycloalkyl) carboxyl esters (e.g. t-butyl, methyl cyclopentyl, methyl cyclohexyl, methyl adamantyl), ester ketals and ester acetals . Tertiary butyl carboxyl esters are the most preferred acid labile protective moieties. If desired, combinations of cyclic olefin units (ii) with other protective functional groups can be used.

In addition, in a first aspect, for photolithography applications used in the manufacture of integrated circuit structures and other microstructures, the cyclic olefin polymer of the present invention preferably contains from about 5 to 80 mole% of the cyclic olefin unit (i) It contains. When the cyclic olefin unit (i) consists mainly of carboxylic acid functionalized units, the cyclic olefin polymer of the present invention is preferably about 5 to 30% by weight, more preferably about 10 to 25% by weight, most preferably It contains about 10 to 20 mol%. When the cyclic olefin unit (i) consists mainly of other acid functionalized units, the cyclic olefin polymer of the invention preferably contains about 10 to 80% by weight, most preferably about 20 to 40 mol%. When carboxylic acid is used as the acidic group, the cyclic olefin polymer of the present invention contains at least about 30 mol%, more preferably about 40 to 90 mol%, most preferably 80 to 90 mol% of cyclic olefin units (ii) or If used, other acid functionalized units contain from about 60 to 80 mole percent. The cyclic olefin polymer of the present invention may contain other monomer units in addition to the olefin units (i) and (ii). Preferably, the cyclic olefin polymers of the present invention contain up to about 40 mol%, more preferably up to about 20 mol% of such other monomer units. Most preferably, the cyclic olefin polymer of the invention consists essentially of the cyclic olefin units (i) and (ii).

In a second aspect, the photoresist composition of the invention is preferably

(a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal cycloaliphatic component, wherein the cyclic olefin polymer (a)

(i) cyclic olefin units having a polar functional moiety selected from acidic and non-acidic polar moieties which increase solubility in aqueous alkali solution, and

(ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

In a third aspect, the photoresist composition of the present invention is preferably

(a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal poly-alicyclic component (HNMP) containing a plurality of acid labile bonds, wherein the cyclic olefin polymer is

(i) cyclic olefin units having a polar functional moiety selected from acidic residues and non-acidic polar moieties which enhance solubility in aqueous alkali solution, and

(ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

In a fourth aspect, the photoresist composition of the invention is preferably

(a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a saturated steroid component, wherein the cyclic olefin polymer

(i) cyclic olefin units having a polar functional moiety selected from acidic residues and non-acidic polar moieties which enhance solubility in aqueous alkali solution, and

(ii) cyclic olefin units having acid labile moieties that inhibit solubility in aqueous alkali solution.

In the second to fourth embodiments, the cyclic olefin unit (i) may be a cyclic olefin monomer unit having an acidic polar functional group which promotes alkali solubility or a cyclic olefin monomer unit having a non acidic polar group. Examples of the cyclic olefin monomers include monomers of the following general formula (1).

Formula 1

Where

R ₁ is a polar residue,

n is zero or some positive integer.

More preferably, the cyclic olefin unit (i) is selected from formulas 2a and 2b.

Formula 2a

Formula 2b

Where

R ₁ is an acidic polar moiety or non-acidic polar group that enhances solubility in aqueous alkali solution. Preferred acidic polar residues have a pK _a of about 13 or less. Preferred acidic polar moieties contain those selected from the group consisting of carboxyl, sulfonamidyl, fluoroalcohols and other acidic polar groups. Preferred acidic polar moieties are carboxyl groups. Non-acidic polar residues preferably have _a pK _a greater than 13 and contain one or more heteroatoms such as oxygen, nitrogen or sulfur. If desired, combinations of cyclic olefin units (i) with other polar functional groups can be used. Preferably, some or all of the cyclic olefin units (i) have acidic polar functional groups.

The cyclic olefin unit (ii) may be a cyclic olefin monomer unit having an acid labile moiety that inhibits solubility in aqueous alkali solution. Examples of the cyclic olefin monomers include monomers of the following general formula (3).

Formula 3

Where

R ₂ is an acid labile protective moiety,

n is zero or some positive integer.

More preferably, the cyclic olefin unit (ii) is selected from the formulas 4a and 4b.

Formula 4a

Formula 4b

Where

R ₂ is an acid labile protective moiety. Preferred acid labile protecting moieties are selected from the group consisting of tertiary alkyl (or cycloalkyl) carboxyl esters (e.g. t-butyl, methyl cyclopentyl, methyl cyclohexyl, methyl adamantyl), ester ketals and ester acetals . Tertiary butyl carboxyl esters are the most preferred acid labile protective moieties. If desired, combinations of cyclic olefin units (ii) with other protective functional groups can be used.

In the second to fourth aspects, for photolithography applications used in the manufacture of integrated circuit structures and other microstructures, the cyclic olefin polymers of the present invention are preferably at least about 20 mol%, more preferably from about 40 to 90 mol%, most preferably about 60 to 90 mol% of cyclic olefin units (ii). The cyclic olefin polymer of the present invention contains about 10 to 80 mol%, more preferably 10 to 60 mol% of the cyclic olefin unit (i). If the cyclic olefin units (i) comprise units having carboxylic acid polar groups, these units are preferably from about 5 to 30% by weight, more preferably from about 10 to 25% by weight, most preferably based on the total cyclic olefin polymer composition Preferably from about 10 to 20 mole percent. If the cyclic olefin units (i) comprise units having sulfonamidyl acidic polar groups, these units are preferably from about 15 to 50% by weight, more preferably from about 20 to 40 mole%, based on the total cyclic olefin polymer composition. It contains. The cyclic olefin polymer of the present invention may contain other monomeric units in addition to units (i) and (ii). Preferably, the cyclic olefin polymers of the present invention contain up to about 40 mol%, more preferably up to about 20 mol% of such other monomer units. Most preferably, the cyclic olefin polymer of the invention consists essentially of the cyclic olefin units (i) and (ii).

The photoresist composition of the present invention is further characterized by the presence of hydrophobic nonsteroidal cycloaliphatic ("HNA") components. The HNA component generally enables and / or improves the ability to decompose ultrafine lithographic shapes corresponding to conventional aqueous alkaline developers. The HNA component is characterized by the presence of a nonsteroidal alicyclic structure (ie, a structure that does not contain the C ₁₇ condensed cyclic structure of the steroid compound). The alicyclic ring structure preferably has 6 (C ₆ ) or more carbon atoms, more preferably 10 or more carbon atoms, and most preferably about 10 to 30 carbon atoms. The total HNA additives preferably have at least about 14 carbon atoms, more preferably 14 to 50 carbon atoms. In some cases, the HNA additives of the present invention may contain one or more alicyclic moieties. If the composition comprises two alicyclic moieties, they are preferably separated by acid labile linking groups. Examples of such multi-alicyclic compounds are shown in the following formula (5).

Preferably, the HNA component contains at least one pendant acid labile moiety (e.g., a moiety that provides a molecule that acts to enhance alkali solubility by splitting the moiety corresponding to the acid generated in the photolithographic method). do. Preferred acid labile moieties are selected from tertiary alkyl (or cycloalkyl) carboxyl esters (eg t-butyl, methyl cyclopentyl, methyl cyclohexyl, methyl adamantyl), ester ketals and ester acetals. t-butyl carboxylate is a preferred acid labile pendant group. The HNA component may also contain pendant groups that increase the volume of the molecule and / or increase the hydrophobicity of the molecule in a manner that improves the performance of the photoresist composition. The pendant acid labile residue (s), if present, may be separated from the cycloaliphatic residue by one or more spacer groups. If desired, combinations of HNA components can be used.

Examples of preferred HNA components include carboxyl esters of adamantane and higher condensed alicyclic ring systems. The most preferred HNA component is adamantane t-butyl carboxylate.

Some examples of HNA components are represented by the following formulas 6-9.

The photoresist composition of the present invention is further characterized by the presence of a hydrophobic nonsteroidal multi-alicyclic component (“HNMP”) containing a plurality of acid labile linking groups. The HNMP component generally enables and / or improves the ability to decompose ultrafine lithographic shapes corresponding to conventional aqueous alkaline developers. The HNMP component is characterized by the presence of two or more unique nonsteroidal cycloaliphatic structures (ie, structures that do not contain the C ₁₇ condensed cyclic structure of the steroid compound). The alicyclic ring structure preferably has 7 (C ₇ ) or more, more preferably about 10 to 30 carbon atoms, except for pendant groups. The total HNMP component preferably has about 20 to 60 carbon atoms.

Broadly, the HNMP component includes compounds containing two or more acid labile linking groups and two or more cycloaliphatic residues such that an acid labile bond is between two or more cycloaliphatic residues.

HNMP compounds contain plural acid labile binding moieties and plural alicyclic moieties. One structure of the compound may be represented by the following formula (10).

The bond between R and X is acid labile such that at least one X _c -R derivative is formed by acid cleavage of the RX bond, where X _c is an acidic polar pendant group from R '. n is 2 or more. If R contains an alicyclic moiety, at least one R 'includes an alicyclic moiety. If R does not contain an alicyclic moiety, at least two R 'groups each comprise an alicyclic moiety. If X is a carboxyl group, the structure is of formula 11 wherein the bond at RO is acid labile. After cleavage, the carboxylic acid group remains pendant on R '. If n is 2 and R 'is an adamantane residue, the structure may be of formula (12), where R is preferably a combination of acid labile ester groups, e.g. two t-butyl ester groups bonded together ( Formula 12a (1 indicates the location of the acid labile binding site) or some other acid labile bond. The result of the cleavage will be a plurality of compounds containing an R 'moiety with pendant carboxylic acid groups.

Alternatively, the HNMP compound may have Formula 13 wherein the bond between R 'and X' is acid labile so that the R- (X _c ) _{n '} derivative is formed by acid cleavage of the R'-X' bond Where X _c is an acidic polar pendant group from R. n 'is two or more. At least one R 'comprises at least one of an alicyclic moiety and a total of R, or the remaining R' residues comprise an alicyclic moiety. In some cases the final result after cleavage will be the production of two smaller molecules each containing a cycloaliphatic residue and the generation of multiple polar functional groups from R.

When X is a carboxyl group, it becomes following formula (14).

After cleavage, R contains plural (n ') carboxylic acid pendant groups. When R is a norbornyl alicyclic, n 'is 2, and R' each contains adamantane, the HNM additive may have the following formula (15).

After cleavage, the norbornyl compound may have two pendant carboxylic acid groups.

Examples of other possible HNMP additive structures include the following formulas (16) and (17).

In the HNMP compounds used in the present invention, the acid labile linking groups advantageously react with the acids produced in the photolithographic method to cleave residues to provide molecules or substantially reduced molecular weights to provide alkali solubility of the radiation exposed portion of the photoresist. It works to promote. Preferred acid labile binding moieties are at least one selected from tertiary alkyl (or cycloalkyl) carboxyl esters (e.g. t-butyl, methyl cyclopentyl, methyl cyclohexyl, methyl adamantyl), ester ketals and ester acetals It contains a residue. The HNMP component may also contain pendant groups that increase the volume of the molecule and / or increase the hydrophobicity of the molecule in a manner that improves the performance of the photoresist composition. If desired, combinations of HNMP components may be used.

Examples of preferred HNMP components include bis-carboxyl esters of adamantane and higher fused ring systems. Most preferred HNA component is bis-adamantane t-butyl carboxylate.

The photoresist composition of the present invention is further characterized by the presence of a saturated steroid (SS) component. The SS component generally enables and / or improves the ability to decompose ultrafine lithographic shapes corresponding to conventional aqueous alkaline developers. The SS component is characterized by the presence of at least one saturated steroid (C ₁₇ ) alicyclic skeletal structure. Saturated steroid components may include compounds having plural saturated steroid residues (eg, bis-steroids or tris-steroids). Preferably, the SS component is selected from the group consisting of acid labile moieties (e.g., moieties that act to enhance the alkali solubility by reacting with the acid produced in the photolithographic method to cleave the moiety to provide molecules). It contains at least two pendant groups. Preferred SS components may contain residues selected from the group consisting of further pendant groups such as formyl groups, hydroxyl groups and trifluoroacetyl groups. The pendant acid labile moiety (s) may be separated by one or more spacer groups such as represented by the structure below. Generally, more hydrophobic SS components are preferred. If desired, a combination of SS components may be used.

Examples of preferred SS components include cholate esters (eg t-butyl litocholate, t-butyldeoxycholate, t-butyl cholate), ester-modified litocholate (eg t-butyl-3-tri Fluoroacetylritocholate, t-butyl-3-acetylritocholate, t-butyl-3-pivalilitocholate), ester-modified cholate esters (e.g. t-butyl-3,7,12-tri Formylcholate, t-butyl-tris- (3,7,12-trifluoroacetyl) cholate and lithocholate having a space such as the following: Most preferred SS component is t-butyl-3-trifluoro Acetylritocholate.

(At this time tBu is a tertiary butyl group)

In addition to the cyclic olefin polymer, the photoresist composition of the present invention contains a photosensitive acid generator (PAG). The present invention is not limited to the use of any particular PAG or combination of PAGs, ie, the advantages of the present invention can be made using various photosensitive acid generators known in the art. Preferred PAGs are those containing reduced amounts (or preferably none) of aryl moieties. If aryl containing PAGs are used, the absorption properties of the PAGs at 193 nm may limit the amount of PAGs that may be included in the formulation.

Examples of suitable photosensitive acid generators are onium salts (but preferably alkyl substituted for one or more of the indicated aryl moieties) such as triaryl sulfonium hexafluoroantimonate, diaryliodonium Hexafluoroantimonate, hexafluoroacenate, triflate, perfluoroalkali sulfonate (e.g. perfluoromethane sulfonate, perfluorobutane, perfluorohexane sulfonate, perfluorooctane Sulfonates, etc.), substituted aryl sulfonates, for example pyrogallol (e.g., trimethylate of pyrogallol or tri (sulfonate) of pyrogallol), sulfonate ester of hydroxyimide, N-sulfonyl Oxynaphthalimide (N-camphorsulfonyloxynaphthalimide, N-pentafluorobenzenesulfonyloxynaphthalimide), α-α'bissulfonyl diazomethane, naphthoquinone-4-dia Zaid, alkyl di It comprises a phone and the like.

The photoresist composition of the present invention is further characterized by the presence of a bulky hydrophobic additive (“BH” additive) that is substantially transparent to 193 nm radiation. BH additives generally enable and / or improve the ability to decompose ultrafine lithographic shapes corresponding to conventional aqueous alkaline developers. The BH additive is preferably characterized by the presence of one or more cycloaliphatic residues. Preferably, the BH additive has about 10 or more carbon atoms, more preferably about 14 or more carbon atoms, and most preferably about 14 to 60 carbon atoms. The BH additive preferably contains one or more additional groups such as acid labile pendant groups that cleave in the presence of an acid to provide a component that acts to enhance the alkali solubility of the radiation exposed portion of the photoresist. Preferred BH additives are selected from the group consisting of saturated steroid compounds, nonsteroidal cycloaliphatic compounds, and nonsteroidal poly-alicyclic compounds having a plurality of acid labile linkages between two or more cycloaliphatic residues. More preferred BH additives include litocholates such as t-butyl-3-trifluoroacetyllitocholate, t-butyl adamantane carboxylate and bis-adamantyl-t-butyl carboxylate. If desired, a combination of BH additives may be used.

The photoresist compositions of the invention will typically contain a solvent prior to applying them to the desired substrate. The solvent may be any solvent that can be conventionally used with acid promoted photoresist that does not otherwise adversely affect the performance of the photoresist composition. Preferred solvents are propylene glycol monomethyl ether acetate, cyclohexanone and ethyl cellosolve acetate.

The compositions of the present invention may further contain small amounts of auxiliary components, such as dyes / photosensitive agents, base additives, and the like, known in the art. Preferred base additives are weak bases that remove traces of acid without excessively affecting the performance of the photoresist. Preferred base additives are (aliphatic or cycloaliphatic) tertiary alkyl amines or t-alkyl ammonium hydroxides, for example t-butyl ammonium hydroxide (TBAH).

The photoresist composition of the present invention preferably contains about 0.5 to 20% by weight (more preferably about 3 to 15% by weight) of the photosensitive acid generator based on the total weight of the cyclic olefin polymer in the composition. If solvent is present, the overall composition preferably contains about 50 to 90 weight percent solvent. The composition preferably contains up to about 1% by weight of said base additive based on the total weight of the subtractive polymer. The photoresist composition of the present invention preferably has a BH of at least about 5% by weight, more preferably from about 10 to 25% by weight, most preferably from about 10 to 20% by weight, based on the total weight of the cyclic olefin polymer in the composition. It contains an additive component.

The present invention is not limited to any particular method of synthesizing the cyclic olefin polymer used in the present invention. Preferably, the cyclic olefin polymer is formed by addition polymerization. Examples of suitable techniques are US Pat. Nos. 5,468,819 and 5,705,503, assigned to B.F. Goodrich Company, which are incorporated herein by reference.

The cyclic olefin polymers of the present invention have a weight average molecular weight of about 5,000 to 100,000, more preferably about 10,000 to 50,000.

The photoresist compositions of the present invention can be prepared by combining cyclic olefin polymers, PAGs, BH additives, HNA components, HNMP components, SS components and any other desired components using conventional methods. Photoresist compositions used in photolithographic methods will generally have a significant amount of solvent.

The photoresist composition of the present invention is particularly useful for photolithographic methods used in the manufacture of integrated circuits on semiconductor substrates. The composition is particularly useful for photolithographic methods using 193 nm UV radiation. If the use of other radiation (eg, medium-UV, 248 nm deep UV, x-ray or e-beam) is desired, the composition of the present invention can be adjusted by adding a suitable dye or photosensitizer to the composition (if necessary). ). General use of the photoresist compositions of the invention in photolithography for semiconductors is described below.

Semiconductor photolithography applications include the transfer of a pattern to a layer of material on a semiconductor substrate. The material layer of the semiconductor substrate may be a metal conductor layer, a ceramic heat transfer layer, a semiconductor layer or other material depending on the step of the manufacturing method and the desired material for the final product. In many cases, an antireflective coating (ARC) is applied onto the material layer prior to application of the photoresist layer. The ARC layer can be any conventional ARC that is compatible with acid promoted photoresist.

Typically, solvent containing photoresist compositions are applied to the desired semiconductor substrate using spin coating or other techniques. Subsequently, the substrate with the photoresist coating is preferably heated (pre-exposure heating) to remove the solvent and improve the binding force of the photoresist layer. The thickness of the applied layer is preferably as thin as possible if it is substantially uniform and the photoresist layer is sufficient to withstand subsequent processing (typically reactive ion etching) to deliver the lithographic pattern to the underlying substrate material layer. The pre-exposure bake step is preferably performed for about 10 seconds to 15 minutes, more preferably about 15 seconds to 1 minute. The pre-exposure bake temperature may vary depending on the glass transition temperature of the photoresist. Preferably, the pre-exposure bake is performed at a temperature at least 20 ° C. below the T _g .

After removing the solvent, the photoresist layer is then exposed at the location to be patterned to the desired radiation (eg, 193 nm ultraviolet radiation). When a scanning particle beam, for example an electron beam, is used, the exposure of the position to be patterned can be made by scanning the beam across the substrate and selectively applying the beam in the desired pattern. More typically, when the wavy radiation forms radiation, such as 193 nm ultraviolet radiation, exposure of the location to be patterned is performed through a mask located on the photoresist layer. For 193 nm UV radiation, the total exposure energy is preferably about 100 mJ / cm ² or less, more preferably about 50 mJ / cm ² or less (eg 15 to 30 mJ / cm ² ).

After exposure of the desired position to be patterned, the photoresist layer is typically heated to further complete the acid promoted reaction and improve the contrast of the exposed pattern. Post-exposure heating is preferably performed at about 100 to 175 ° C, more preferably at about 125 to 160 ° C. Post-exposure heating is preferably performed for about 30 seconds to 5 minutes.

After the post-exposure bake, a photoresist structure having the desired pattern is obtained (developed) by contacting the photoresist layer with an alkaline solution, selectively dissolving areas of the photoresist and exposing to radiation. Preferred alkaline solutions (developers) are aqueous solutions of tetramethyl ammonium hydroxide. Preferably, the photoresist composition of the present invention can be developed with conventional 0.26 N alkaline aqueous solution. Photoresist compositions of the invention can also be developed using 0.14 N or 0.21 N or other aqueous alkaline solutions. The photoresist composition produced on the substrate is then typically dried to remove any residual developer solvent. Photoresist compositions of the present invention are generally characterized in that the resulting photoresist structures have high etch resistance. In some cases, it may be possible to further improve the etch resistance of the photoresist structure using post-silylation techniques known in the art. The compositions of the present invention allow for the reproduction of lithographic shapes.

The pattern from the photoresist structure may then be transferred to the material (eg, ceramic, metal or semiconductor) of the underlying substrate. Typically, the transfer is by reactive ion etching or some other etching technique. In reactive ion etching, the etch resistance of the photoresist layer is particularly important. Thus, the compositions of the present invention and the resulting photoresist structures can be used in the design of patterned material layer structures, for example integrated circuit devices, holes for metal wiring, contacts or vias, insulators (eg, waves). Patterned trench or shallow trench isolation), trenches for capacitor structures, and the like.

Methods of making these (ceramic, metal or semiconductor) shapes are generally intended to provide and pattern portions of material layers or substrates, to apply layers of photoresist onto material layers or portions, and to pattern photoresists. Exposing the photoresist with a solvent to develop the pattern, etching the layer (s) underneath the photoresist layer in the space within the pattern to form a patterned material layer or substrate portion. And removing any residual photoresist from the substrate. In some cases, hard masks may be used under the photoresist layer to further facilitate transferring the pattern to underlying material layers or portions. Examples of such methods are described in US Pat. No. 4,855,017; No. 5,362,663; No. 5,429,710; 5,562,801; 5,562,801; 5,618,751; No. 5,744,376; No. 5,801,094; And 5,821,469, which are incorporated herein by reference. Other examples of pattern transfer methods are described in Chapter 12 and 13 of "Semiconductor Lithography, Principles, Practices, and Materials" by Wayne Moreau, Plenum Press, (1988). It is contemplated that the invention should not be limited to any particular lithography technique or device structure.

Example 1 (comparative)

For the purpose of lithographic experiments, photoresist formulations containing norbornene copolymers containing 85% norbornene t-butylester (NB-t-BE) and 15% norbornene-carboxylic acid (as pendant groups) Was prepared by combining the following disclosed materials expressed in parts by weight.

Propylene Glycol Monomethyl Ether Acetate 37 Copolymers of NB-t-BE and NB-CA (85/15) 4 Di-t-butylphenyl iodonium perfluorooctanesulfonate 0.16 Tetrabutyl ammonium hydroxide 0.008

The photoresist formulation was spin-coated (for about 30 seconds) onto an antireflective material (ArX®, Shipley Company) layer applied onto the silicon wafer. The photoresist layer was gently heated at 130 ° C. for 60 seconds on a vacuum hot plate to produce a film of about 0.4 μm thick. The wafer was then exposed to 193 nm radiation (0.6 NA ArF, ISI stepper). The exposure pattern is a series of streak patterns whose size decreases to 0.1 μm. The exposed wafers were post-exposure baked on a vacuum hot plate at 150 ° C. for 90 seconds. The pattern exposed photoresist was then developed (puddle) using a 0.263 N tetramethyl ammonium hydroxide developer. The pattern was then examined by scanning electron microscopy (SEM). The cross-sectional SEM pattern did not show resolutions below 200 nm L / S (lined pair) due to the collapse of the lines. Even the striae pairs above 200 nm did not dissolve as a whole due to excessive scumming / residue between the lines.

Example 2

This example illustrates the advantages of the compositions of the present invention containing saturated steroid additives. Photoresist formulations were prepared by combining the materials disclosed below expressed in parts by weight.

Propylene Glycol Monomethyl Ether Acetate 38 poly (norbornene) with t-BE and CA groups (t-BE / CA: 85/15) 4 Di-t-butylphenyl iodonium perfluorooctanesulfonate 0.16 t-butyl-3-trifluoroacetyltricholate 0.4 Tetrabutyl ammonium hydroxide 0.008

The photoresist formulation was spin-coated onto an antireflective material (ArX®, Shipley Company) applied onto the silicon wafer in the same manner as in Example 1, exposed to the position to be patterned (193 nm). Radiation). The resulting pattern was then irradiated with a scanning electron microscope (SEM). Stroke pairs of 140 nm and above were well resolved to a clean profile. The exposure energy required for this formulation is 25 to 35 mJ / cm ² .

Example 3

Synthesis of Adamantane-1-carboxylic acid t-butyl ester

To a suspension containing 25.34 g (0.342 mol) t-butyl alcohol in 600 mL methylene chloride was added 38.07 g (0.3815 mol) triethylamine at room temperature. The resulting suspension was stirred at room temperature until this turned to a clear solution. 74.75 g (0.3762 mol) of adamantane-1-carbonyl chloride was added to the solution at 0 ° C. After the addition was complete, the reaction mixture was stirred at room temperature for 12 hours and subsequently at reflux for 2 hours. The reaction mixture was filtered to remove triethylamine hydrochloride formed during the reaction. The filtrate was washed several times with water (× 500 mL), dried over anhydrous sodium sulfate and concentrated under reduced pressure. Purification of the residue via column chromatography (silica gel; hexane / methylene chloride: 9: 1) yields 48.4 g (about 60%) of a white solid, which is adamantane-1-carboxylic acid t by NMR spectroscopy. It was confirmed by -butyl ester.

Example 4

This example illustrates the advantages of the compositions of the present invention containing adamantane-1-carboxylic acid t-butylester. Photoresist formulations were prepared by combining the materials disclosed below expressed in parts by weight.

Propylene Glycol Monomethyl Ether Acetate 38 poly (norbornene) with t-BE and CA groups (t-BE / CA: 85/15) 4 Di-t-butylphenyl iodonium perfluorooctanesulfonate 0.16 Adamantane-1-carboxylic acid t-butyl ester (Example 3) 0.4 Tetrabutyl ammonium hydroxide 0.008

The photoresist formulation was spin-coated onto an antireflective material (ArX®, Shipley Company) on a silicon wafer in the same manner as in Example 1, exposed to the position to be patterned (193 nm radiation), Developed. The resulting pattern was then examined by scanning electron microscopy (SEM). Stroke pairs of 140 nm and above were well resolved to a clean profile. The exposure energy required for this formulation is 20 to 30 mJ / cm ² .

Example 5

Synthesis of 2,5-bis (adamantane-1-carboxyoxy) -2,5-dimethylhexane

To a suspension containing 50 g (0.342 mol) 2,6-dimethyl-2,5-hexanediol in 600 ml methylene chloride, 76.14 g (0.762 mol) triethylamine were added at room temperature. The resulting suspension was stirred at room temperature until this turned to a clear solution. 149.5 g (0.7524 mol) of adamantane-1-carbonyl chloride was added to the solution at 0 ° C. After the addition was complete, the reaction mixture was stirred at room temperature for 12 hours and subsequently at reflux for 2 hours. The reaction mixture was filtered to remove triethylamine hydrochloride formed during the reaction. The filtrate was washed several times with water (× 500 mL), dried over anhydrous sodium sulfate and concentrated under reduced pressure. Purification of the residue via column chromatography (silica gel; hexane / methylene chloride: 9: 1) yields 128 g (-80%) of a white solid, which is 2,5-bis (adama) by NMR spectroscopy. Tan-1-carboxyloxy) -2,5-dimethylhexane.

Example 6

This example illustrates the advantages of the compositions of the present invention containing 2,5-bis (adamantane-1-carboxyoxy) -2,5-dimethylhexane. Photoresist formulations were prepared by combining the materials disclosed below expressed in parts by weight.

Propylene Glycol Monomethyl Ether Acetate 38 poly (norbornene) with t-BE and CA groups (t-BE / CA: 85/15) 4 Di-t-butylphenyl iodonium perfluorooctanesulfonate 0.16 2,5-bis (adamantane-1-carboxyoxy) -2,5-dimethylhexane (Example 5) 0.4 Tetrabutyl ammonium hydroxide 0.008

The photoresist formulation was spin-coated onto an antireflective material (ArX®, Shipley Company) on a silicon wafer in the same manner as in Example 1, exposed to the position to be patterned (193 nm radiation), Developed. The resulting pattern was then irradiated with a scanning electron microscope (SEM). Stroke pairs of 130 nm and above were well resolved to a clean profile. The exposure energy required for this formulation is 20 to 30 mJ / cm ² .

Example 7

500 g (1.328 mol) of lytocholic acid and 4 L of dry THF were added to a 12 L four-necked round bottom flask equipped with an 1 L constant pressure addition funnel with an overhead stirrer, thermocouple temperature monitor and nitrogen inlet. The addition funnel was then charged with 1920 mL (13.6 mol) of trifluoroacetic anhydride. The flask was cooled on ice under nitrogen and trifluoroacetic anhydride was added in a dilute stream while maintaining a temperature below 10 ° C. After the mixture was allowed to warm to room temperature with stirring overnight, the solvent and excess trifluoroacetic anhydride were removed on a rotary evaporator. The thick viscous intermediate was sent back to a 12 L flask and refilled with an additional 4 L THF. The addition funnel was charged with 740 g (10 mol) of t-butyl alcohol (diluted with a small amount of THF to prevent coagulation). The flask was cooled again with ice and t-butyl alcohol was added in a dilute stream while maintaining a temperature below 10 ° C. The mixture was allowed to reach room temperature with stirring overnight. Then about 200 g of solid NaHCO ₃ was added and stirring continued for an additional 2 hours. Solvent and excess t-butyl alcohol were removed on a rotary evaporator and the mixture was placed in 4 L of ethyl ether and carefully washed with 3 x 800 ml of saturated NaHCO ₃ followed by 2 x 1000 ml of water. The solvent was dried over MgSO ₄ for 1 h with stirring, filtered and evaporated on a rotary evaporator. The thick viscous residue was slowly eluted with hexane through a large column containing 800 g of silica gel in hexane. The mixed product fractions were evaporated on a rotary evaporator and the remaining solvent was removed by constant weight under vacuum at 40 ° C. under a dilute stream of nitrogen to yield 620 g (88%) of the desired product as an off-white syrup. This material was crystallized from pentane continuously at −78 ° C. to give a low melting white wax.

Example 8

This example illustrates the benefits of the additives of the present invention. Photoresist formulations were prepared by combining the materials disclosed below expressed in parts by weight.

Propylene Glycol Monomethyl Ether Acetate 38 poly (norbornene) with t-BE and CA groups (t-BE / CA: 85/15) 4 Di-t-butylphenyl iodonium perfluorooctanesulfonate 0.16 t-butyl-3-trifluoroacetyltricholate (Example 2) 0.4 Tetrabutyl ammonium hydroxide 0.008

The photoresist formulation was spin-coated onto an antireflective material (ArX®, Shipley Company) on a silicon wafer in the same manner as in Example 1, exposed to the position to be patterned (193 nm radiation), Developed. The resulting pattern was then irradiated with a scanning electron microscope (SEM). Stroke pairs of 140 nm and above were well resolved to a clean profile. The exposure energy required for this formulation is 25 to 35 mJ / cm ² .

The photoresist compositions of the present invention can image with shorter wavelength radiation while having good developability and anti-etching properties.

Claims (39)

delete delete (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal multi-alicyclic component containing a plurality of acid labile linking groups, The cyclic olefin polymer (a) comprises (i) a cyclic olefin unit having a polar functional residue, and (ii) an cyclic olefin unit having an acid labile residue which inhibits solubility in an aqueous alkali solution, Wherein said hydrophobic nonsteroidal multi-alicyclic component (c) comprises at least two nonsteroidal cycloaliphatic residues of C ₇ or higher; Photoresist composition. delete delete delete The method of claim 3, wherein A polar functional residue (i) is selected from the group consisting of acidic and polar functional residues having _a pK _a of 13 or less, nonacidic and polar functional residues having _a pK _a greater than 13, and combinations thereof Photoresist composition. The method of claim 7, wherein A photoresist composition wherein the cyclic olefin unit (i) contains an acidic and polar functional moiety comprising an acidic and polar group selected from the group consisting of carboxyl, sulfonamidyl, fluoroalcohol, and other acidic and polar groups. The method of claim 3, wherein Photoresist composition wherein the cyclic olefin unit (ii) contains an acid labile protecting group containing a moiety selected from the group consisting of tertiary alkyl carboxyl esters, tertiary cycloalkyl carboxyl esters, ester ketals, and ester acetals. delete The method of claim 3, wherein A photoresist composition wherein the hydrophobic nonsteroidal multi-alicyclic component (c) comprises two or more nonsteroidal alicyclic moieties of C ₁₀ -C ₃₀ . The method of claim 3, wherein A photoresist composition wherein the hydrophobic nonsteroidal multi-alicyclic component (c) comprises two acid labile linking moieties. delete delete delete delete delete The method of claim 12, A photoresist composition wherein the hydrophobic nonsteroidal multi-alicyclic component (c) comprises an acid labile linking moiety selected from the group consisting of tertiary alkyl carboxyl esters, tertiary cycloalkyl carboxyl esters, ester ketals, and ester acetals. The method of claim 12, A photoresist composition wherein two acid labile linking moieties are two tertiary alkyl carboxyl esters bonded to one another. delete delete delete The method of claim 3, wherein A photoresist composition comprising from 5 to 25% by weight of hydrophobic nonsteroidal alicyclic component (c) based on the weight of the cyclic olefin polymer (a). delete The method of claim 3, wherein The composition wherein the cyclic olefin polymer contains 10 to 80 mol% of cyclic olefin units i) and 20 to 90 mol% of cyclic olefin units ii). delete A method of forming a patterned photoresist structure on a substrate, the method comprising: (A) a hydrophobic nonsteroidal multi-alicyclic component containing (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a plurality of acid labile linking groups, The cyclic olefin polymer (a) comprises (i) a cyclic olefin unit having a polar functional residue, and (ii) an cyclic olefin unit having an acid labile residue which inhibits solubility in an aqueous alkali solution, Forming an alicyclic component (c) photoresist layer on the substrate by coating a photoresist composition comprising at least ₇ C nonsteroidal two or more cycloaliphatic moieties to a substrate, wherein the hydrophobic non-steroidal multiple (B) exposing the substrate to radiation at a location to be patterned to generate acid by the photosensitive acid generator in an exposed area of the photoresist layer by radiation, and (C) contacting the substrate with an aqueous alkaline developer solution to selectively dissolve an exposed area of the photoresist layer with a developer to reveal the patterned photoresist structure on the substrate. A method of forming a patterned photoresist structure. The method of claim 27, A method of forming a patterned photoresist structure wherein the radiation used in step (B) is 193 nm ultraviolet light. The method of claim 27, A method of forming a patterned photoresist structure, wherein the substrate is baked between steps (B) and (C). A method of forming a patterned material structure on a substrate, (A) providing a substrate with a layer of a material selected from the group consisting of semiconductors, ceramics and metals, (B) a hydrophobic nonsteroidal multi-alicyclic component containing (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a plurality of acid labile linking groups, The cyclic olefin polymer (a) comprises (i) a cyclic olefin unit having a polar functional residue, and (ii) an cyclic olefin unit having an acid labile residue which inhibits solubility in an aqueous alkali solution, Applying a photoresist composition to the substrate, wherein the hydrophobic nonsteroidal multi-alicyclic component (c) comprises at least two nonsteroidal cycloaliphatic residues of C ₇ or more to form a photoresist layer on the material layer, (C) exposing the substrate to radiation at a location to be patterned to generate acid with a photosensitive acid generator in an exposed area of the photoresist layer by radiation; and (D) contacting the substrate with an aqueous alkaline developer solution to selectively dissolve an exposed area of the photoresist layer with a developer to reveal a patterned photoresist structure, and (E) etching through the space in the photoresist structure pattern into the material layer to transfer the photoresist structure pattern to the material layer; Method of Forming Patterned Material Structures. The method of claim 30, A method of forming a patterned material structure wherein the material is a metal. The method of claim 30, A method of forming a patterned material structure wherein the etching comprises reactive ion etching. The method of claim 30, At least one intermediate layer is provided between the material layer and the photoresist layer, and step (E) comprises etching through the intermediate layer. The method of claim 30, A method of forming a patterned material structure in which the radiation has a wavelength of 193 nm. The method of claim 30, A method of forming a patterned material structure wherein a substrate is baked between steps (C) and (D). The method of claim 8, A photoresist composition wherein the acidic and polar groups are carboxyl groups. In a positive photoresist structure exposed to radiation along a pattern on a substrate and developed, The photoresist comprises (a) a cyclic olefin polymer, (b) a photosensitive acid generator, and (c) a hydrophobic nonsteroidal multi-alicyclic component containing a plurality of acid labile linking groups, The cyclic olefin polymer (a) comprises (i) a cyclic olefin unit having a polar functional residue, and (ii) an cyclic olefin unit having an acid labile residue which inhibits solubility in an aqueous alkali solution, Wherein said hydrophobic nonsteroidal multi-alicyclic component (c) comprises at least two nonsteroidal cycloaliphatic residues of C ₇ or higher; Positive photoresist structure. delete The method of claim 37, A positive photoresist structure in which the cyclic olefin unit (ii) contains an acid labile protecting group containing a moiety selected from the group consisting of tertiary alkyl carboxyl esters, tertiary cycloalkyl carboxyl esters, ester ketals and ester acetals.