JP3418971B2 - Photoresist composition containing cyclic olefin polymer and additives - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist composition capable of forming a high resolution pattern by adapting to short wavelength radiation, and a pattern forming method using such a resist composition.

[0002]

BACKGROUND OF THE INVENTION There is a continuing need to reduce the size of structural features in the microelectronics industry, as well as other industries involved in the manufacture of microstructures (eg, micromechanics, magnetoresistive heads, etc.). In the microelectronics industry, this need is either to reduce the size of microelectronic devices, to increase the amount of circuitry on a chip of a given size, or both.

The ability to shrink device dimensions is limited by the ability of photolithographic techniques to reliably resolve reduced features and gaps. The nature of optical devices is that their ability to enhance resolution is limited in part by the wavelength of the light (or other radiation) used to create the lithographic pattern. Therefore, there is a continuing trend to shorten the wavelength of light used for photolithography processing. Recently, this tendency is so-called I-ray radiation (350n
m) to 248 nm emission.

Probably 193 for future miniaturization
It is believed that one will come to use nm radiation. Unfortunately, photoresist compositions that are the focus of current photolithography processes using 248 nm radiation are typically
It is not suitable for use at shorter wavelengths.

Photoresist compositions must also have the desired optical properties that are resolvable at the wavelength of radiation of interest, but the photoresist composition has also been image patterned. It must have suitable chemical and mechanical properties for transfer from the photoresist to the underlying substrate layer. Therefore, the positive photoresist exposed according to the pattern must be capable of an adequate resolution response (ie, selective resolution of exposed areas) to obtain the desired photoresist structure. It is important to do extensive experimentation with photolithography techniques using aqueous alkaline developers to achieve proper resolution with such commonly used developer solutions.

The patterned photoresist structure (after development) must be sufficiently resistant to transfer to the underlying layer of the pattern. Generally, pattern transfer is accomplished by some type of wet chemical etching or ion etching.
The ability of the patterned photoresist layer to withstand the pattern transfer etching process (ie, the etch resistance of the photoresist layer) is an important property of the photoresist composition.

Although some photoresist compositions are designed for use at 193 nm radiation, these compositions are generally short due to lack of performance in one or more of the above regions. It does not bring the benefits of true resolution to imaging at wavelength. Therefore, short wavelength radiation (eg 250 nm) with good developability and etching resistance
There is a need for photoresist compositions that can be imaged using shorter, more preferably shorter than 200 nm, and most preferably 193 nm ultraviolet light.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to have good developability and pattern transfer properties, and photoresists capable of producing high resolution photolithographic patterns using short wavelength radiation. It is to provide a composition.

[0009]

SUMMARY OF THE INVENTION The present invention provides photoresist compositions having high resolution lithographic performance using short wavelength, eg, 193 nm, imaging radiation. The photoresist compositions of the present invention have a very high resolution combination of imaging capability, developability, and etch resistance required for pattern transfer, limited only by the wavelength of the imaging radiation. The photoresist compositions of the present invention are generally characterized by the presence of a cycloolefin polymer having a combination of acid labile functional groups and acidic polar functional groups. Photoresist compositions of the present invention are preferably further characterized by the presence of a bulky hydrophobic additive that is substantially transparent to the wavelength of the imaging radiation, such as 193 nm.

The present invention also provides a method of forming a photoresist structure utilizing the photoresist composition of the present invention,
And a method of transferring the pattern to an underlying layer utilizing the photoresist structure. The photolithographic method of the invention is characterized by the use of pattern-wise exposure, preferably with 193 nm UV radiation. The method of the present invention preferably features without the use of a phase shift mask, features having a dimension less than about 150 nm, more preferably less than about 120 nm or less than about 115 n.
Features below m (using optics with a numerical aperture of 0.68) can be resolved.

In one aspect, the invention provides (a) i) a cyclic olefin unit having an acidic polar functional group or a non-acidic polar functional group that promotes solubility in an aqueous alkaline solution, and ii) an aqueous alkaline solution. A cyclic olefin polymer having a cyclic olefin unit having an acid labile group for suppressing solubility therein, (b) a photosensitive component, and (c) substantially transparent to ultraviolet radiation, A photoresist composition having a bulky hydrophobic additive component.

The cyclic olefin polymer of the present invention preferably contains about 5-40 mol% of unit i). The cyclic olefin polymer of the present invention is preferably mainly a cyclic olefin monomer unit, more preferably mainly a unit i).
And units ii). The bulky hydrophobic additive preferably comprises an alicyclic group. Preferred hydrophobic additives are those selected from the group consisting of saturated steroid compounds, nonsteroidal alicyclic compounds, and nonsteroidal polyalicyclic compounds having multiple acid labile bonds.

The cyclic olefin polymer of the present invention is preferably composed mainly of a cyclic olefin monomer unit, more preferably mainly composed of a unit i) and a unit ii).
The unit i) preferably contains an acidic polar group having pK _a ≦ 13. Hydrophobic non-steroidal alicyclic moieties preferably include those containing C ₁₀ or higher alicyclic groups. Also,
The HNMP component of the present invention is preferably one containing a C ₇ or higher alicyclic group, and a compound having a plurality of acidic polar groups, or at least one of each of which is obtained by degrading HNMP with an acid. It is preferable to produce any one of a plurality of compounds having an acidic polar group, or both of them.

In another aspect, the invention includes a method of forming a patterned photoresist structure on a substrate. The method comprises the steps of (a) forming a substrate having a surface layer of a photoresist composition of the present invention, and (b) exposing the photoresist layer to radiation according to a pattern, thereby emitting a portion of the photoresist layer. And (c) exposing the photoresist layer to an alkaline aqueous solution developer to remove the exposed portion of the photoresist layer,
Forming a patterned photoresist structure. Most preferably, the radiation used in step (b) of said method is 193 nm UV radiation.

The present invention also includes processes for making conductive, semiconductive, magnetic, or insulative structures utilizing patterned photoresist structures containing the compositions of the present invention.

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

[0017]

DETAILED DESCRIPTION OF THE INVENTION The photoresist composition of the present invention generally comprises i) a cyclic olefin unit having an acidic polar functional group that promotes solubility in an aqueous alkaline solution, and ii).
The present invention is characterized by the presence of a polymer containing a cyclic olefin unit having an acid labile group that suppresses solubility in an alkaline aqueous solution. The cyclic olefin polymer preferably has a cyclic olefin unit i) of 40 mol% or less. The composition is further characterized by the presence of a bulky hydrophobic additive that is substantially transparent to the wavelength of the imaging radiation. These compositions have good developability and pattern transfer properties and are capable of producing high resolution photolithographic patterns using short wavelength radiation, eg, 193 nm.

The present invention further provides a patterned photoresist structure containing the photoresist composition of the present invention, a method of making such a photoresist structure, and utilizing this photoresist structure to provide a conductive, semi-conductive structure. sex,
And methods of forming all or any of the insulating structures.

The photoresist composition of the present invention generally comprises (a) i) a cyclic olefin unit having an acidic polar functional group that promotes solubility in an aqueous alkaline solution, and ii) suppression of solubility in the aqueous alkaline solution. A cyclic olefin polymer having a cyclic olefin unit having an acid labile group, (b) a photosensitive component, and (c) a bulky additive component substantially transparent to ultraviolet radiation. Have.

The cyclic olefin unit i) used in the resist composition of the present invention is any cyclic olefin monomer unit having an acidic polar group or a non-acidic polar group which promotes solubility in an alkaline aqueous solution. May be Examples of the cyclic olefin monomer include the following monomers represented by the structure (I), in which R ₁ is a polar group and n is 0 or a positive integer.

[Chemical 1]

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

[Chemical 2] In the formula, R ₁ is an acidic polar group or a non-acidic polar group that promotes solubility in an alkaline aqueous solution. The acidic polar group preferably has a pKa of about 13 or less. Preferred acidic polar groups include polar groups selected from the group consisting of carboxyl groups, sulfonamidyl groups, fluoroalcohol groups, and other acidic polar groups. A preferred acidic polar group is a carboxyl group. On the other hand, preferred non-acidic polar groups have a pKa of greater than about 13 and at least one
Contains heteroatoms such as oxygen, nitrogen or sulfur. If desired, it is also possible to use combinations of cyclic olefin units i) having different polar functional groups. Preferably,
At least some or all of the cyclic olefin units i) are acidic polar functional groups.

The cyclic olefin unit ii) may be any cyclic olefin monomer unit having an acid labile group that inhibits solubility in aqueous alkaline solutions. Examples of cyclic olefin monomers include the following monomers represented by structure (III), where R ₂ is an acid labile protecting group, n
Is 0 or a positive integer.

[Chemical 3]

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

[Chemical 4] In the formula, R ₂ represents an acid-labile protecting group. Preferred acid labile protecting groups are those selected from the group consisting of tertiary alkyl (or cycloalkyl) carboxyl esters (eg t-butyl, methylcyclopentyl, methylcyclohexyl, methyladamantyl), ester ketals, and ester acetals. Is. Tertiary butyl carboxyl ester is the most preferred acid labile protecting group. If desired, it is also possible to use combinations of cyclic olefin units ii) with different protective functional groups.

For photolithographic applications used in the manufacture of integrated circuit structures and other microstructures, the cyclic olefin polymer of the present invention comprises from about 5 to 80 mol%, preferably from about 10 to about 60 mol% cyclic olefin polymer. Those containing olefin units i) are preferred. When the cyclic olefin unit i) consists mainly of carboxylic acid functionalized units, the cyclic olefin polymer of the present invention is preferably about 5-30 mol%, more preferably about 10-25 mol%, most preferably About 1
It contains from 0 to 20 mol% of cyclic olefin units i).
If the cyclic olefin units i) consist of units with sulphonamidyl acidic polar groups, these units are preferably about 15 relative to the total cyclic olefin polymer composition.
˜50 mol%, more preferably about 20-40 mol%. When the cyclic olefin unit i) consists mainly of other acidic functionalized units, the cyclic olefin polymer of the present invention is more preferably about 10 to 80 mol%, most preferably about 20 to 40 mol%. Contains the formula olefin unit i). The cyclic olefin polymer of the present invention is at least about 20 mol%, preferably at least about 30 mol%,
More preferably about 40 to 90 mol%, most preferably about 60 to about 90 mol% cyclic olefin units ii).
Contains. When using a carboxylic acid as the acidic group,
About 80-90 mol%, if other acidic functionalized units are used, it is preferred to contain about 60-80 mol% cyclic olefin units ii). The cyclic olefin polymer of the present invention may contain other monomer units in addition to the unit i) and the unit ii). Preferably, such other monomer units contained in the cyclic olefin polymer of the present invention are about 40 mol% or less, more preferably about 20 mol% or less.
It should be at most mol%. More preferably, the cyclic olefin polymer of the present invention comprises substantially unit i) and unit ii).
It consists of only.

The photoresist composition of the present invention contains a photosensitive acid generator (PAG) as a photosensitive component in addition to the cyclic olefin polymer. The present invention describes what specific P
It is not limited to using a combination of AGs or PAGs, ie the advantages of the present invention can be achieved using various photoacid generators well known to those skilled in the art. Preferred PAGs are those containing a small amount (preferably no) of aryl groups. PA containing an aryl group
When G is used, the wavelength of the imaging radiation (eg 193n
The absorption properties of PAG in m) limit the amount of PAG included in the formulation.

Examples of suitable photosensitive acid generators include onium salts such as triarylsulfonium hexafluoroantimonate and diaryliodonium hexafluoroantimonate, hexafluoroarsenate salts, triflates, and perfluoroalkane sulfonates ( Substituted aryl sulfonates such as perfluoromethane sulfonate, perfluorobutane sulfonate, perfluorohexane sulfonate, perfluorooctane sulfonate, etc., pyrogallols (eg, trimesyl acid salt of pyrogallol or trissulfonic acid salt of pyrogallol) , Hydroxyimide sulfonates, N-sulfonyloxynaphthalimides (N-camphor sulfonyloxynaphthalimide, N-pentafluorobenzenesulfonyloxynaphthalimide ), Alpha,. Alpha .'- bis-sulfonyl diazomethane, naphthoquinone-4-diazides, alkyl disulfonates, other is (but that none of the aryl group shown is alkyl substituted are preferred).

The photoresist composition of the present invention further comprises
A bulky hydrophobic additive (“BH”) that is substantially transparent to the wavelength of the imaging radiation (eg, 193 nm).
Additive) is present. BH additives are generally capable of reacting with conventional aqueous alkaline developers to resolve ultrafine lithographic features or enhance resolution. BH additives are preferably those characterized by the presence of at least one alicyclic group. The BH additive preferably contains at least 10 carbon atoms, more preferably contains at least 14 carbon atoms, and most preferably contains 14 to 60 carbon atoms. The BH additive is further acid labile, which decomposes in the presence of one or more acids to produce a component that acts to promote solubility of the radiation exposed portions of the photoresist in aqueous alkaline solutions. Those containing groups such as pendant groups are preferred. The preferred BH additive is a saturated steroid (“S
S ") compound, a non-steroidal alicyclic (" HNA ") compound, and a non-steroidal polyalicyclic (" HNM ") having an acid labile linking group between at least two alicyclic groups.
P ") compound. More preferred BH additives are lithocholic acid-t-butyl-3-trifluoroacetyl, carboxylic acid-t-butyladamantane, and carboxylic acid bisadamantyl-.
There are lithocholic acid salts such as t-butyl. If necessary, two or more kinds of BH additives can be used in combination.

The saturated steroid ("SS") component suitable for the photoresist composition of the present invention is generally reacted with a conventional aqueous alkaline developer to resolve, or resolve, microscopic lithographic features. You can strengthen your ability. The SS component is characterized by the presence of at least one saturated steroid (C ₁₇ ) alicyclic skeleton structure.
The saturated steroid component may consist of a compound having a plurality of saturated steroid groups (for example, bissteroid or trissteroid). Preferably S
The S component is a group consisting of an acid labile group (for example, a group that reacts with an acid generated during a photolithography process to cleave the group to generate a molecule that promotes solubility in an aqueous alkaline solution). It contains one or more pendant groups selected from A preferred SS component may further contain pendant groups such as groups selected from the group consisting of formyl groups, hydroxyl groups, and trifluoroacetyl groups. When present, one or more acid labile pendant groups can be separated by one or more spacer groups, such as structures SL-1 and SL-2 shown below. Generally, highly hydrophobic SS components are preferred. If necessary, a plurality of SS components may be used in combination.

Examples of preferred SS components include cholic acid esters (eg lithocholic acid-t-butyl, deoxycholic acid-t-butyl, cholic acid-t-butyl), ester-modified lithocholic acid esters (eg lithocholic acid-t-butyl).
t-butyl-3-trifluoroacetyl, 3-acetyl lithocholic acid-t-butyl, lithocholic acid-t-butyl-3-pivalyl), ester-modified cholic acid ester (for example, cholic acid-t-butyl-3,7, 12-triformyl, cholate-t-butyl-tris (3,7,12-
Trifluoroacetyl)), and structure SL shown below
There are lithocholic acid esters with spacer groups such as -1 and SL-2.

[Chemical 5]

[Chemical 6] In the formula, tBu is a tertiary butyl group. Most preferred SS
The component is lithocholic acid-t-butyl-3-trifluoroacetyl.

Hydrophobic non-steroidal alicyclic ("HNA") components suitable for the photoresist compositions of the present invention are generally
It can react with conventional aqueous alkaline developers to resolve, or enhance the resolution capabilities of, ultra-small lithographic features. This HNA component has a non-steroidal alicyclic structure (ie, C ₁₇ which is characteristic of steroid compounds).
A structure which does not contain a fused ring structure) is present. This alicyclic structure is preferably one containing at least 6 carbon atoms (C ₆ ), more preferably one containing at least 10 carbon atoms, and 10 to 3
Most preferred are those containing 0 carbon atoms. HNA
The total additive is preferably one containing at least about 14 carbon atoms, and more preferably one containing about 14 to 50 carbon atoms. If desired, the HNA additive of the present invention may contain one or more alicyclic groups. If the composition has two alicyclic groups, it is preferably separated by acid labile linking groups. Such a polyalicyclic compound is represented by the following formula (V).

[Chemical 7]

Preferably, the HNA component reacts with one or more acid labile pendant groups (eg, the acid formed in the photolithography process, which cleaves the group and promotes solubility in aqueous alkaline solutions. It has a functional group). Preferred acid labile groups are tertiary alkyl (or cycloalkyl) carboxylic acid esters,
(E.g. t-butyl, methylcyclopentyl, methylcyclohexyl, methyladamantyl), ester ketals, and ester acetals. The HNA component may also contain pendant groups that increase the bulk of the molecule and / or increase the hydrophobicity of the molecule so as to enhance the properties of the photoresist composition. The one or more acid labile pendant groups can be separated from the alicyclic group by one or more spacer groups. If necessary, HNA components may be used in combination.

Examples of preferred HNA components are carboxylic acid esters of adamantane, and higher fused alicyclic ring structures. The most preferred HNA component is adamantane t-butylcarboxylate.

Some examples of HNA components are those having the structures shown below.

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

Hydrophobic non-steroidal polycycloaliphatic components ("HNMP") containing acid labile linking groups suitable for the photoresist compositions of this invention also generally react with conventional aqueous alkaline developers. Can resolve ultra-small lithographic features or enhance resolution capabilities. The HNMP component is characterized by the presence of at least two distinct nonsteroidal alicyclic structures (ie, structures that do not contain the C ₁₇ fused cyclic structure characteristic of steroid compounds). The alicyclic cyclic structure, those containing at least 7 carbon atoms with the exception of the pendant group (C ₇₎ are preferred, those containing about 10 to 30 carbon atoms more preferred. The total HNMP component is preferably one containing about 20 to 60 carbon atoms.

Generally, the HNMP component comprises at least two acid labile linking groups and at least two alicyclic groups with at least two alicyclic groups having an acid labile bond between them. Included as present compounds.

The HNMP compound contains a plurality of acid labile linking groups and a plurality of alicyclic groups. One of the structures of such compounds is represented by the following formula.

[Chemical 12]

The bond between R and X is an acid such that at least one Xc-R '(Xc is an acidic polar pendant group from R') derivative is formed by acid cleavage of the R-X bond. It is an unstable bond. In the above formula, n is at least 2. When R contains an alicyclic group, at least 1
R'is an alicyclic group. When R does not contain an alicyclic group, at least two R's are each an alicyclic group. When X is a carboxyl group, the structure is as shown below.

[Chemical 13] In the formula, the bond between R and O is an acid-labile bond. After cleavage, the carboxylic acid group remains a pendant group on R '. When n is 2 and R ′ is an adamantane group, the structure is as shown below.

[Chemical 14] Where R is a combination of acid-labile ester groups such as two t-butyl ester groups attached (structure VIIa below, where 1 represents the site of the acid-labile bond) or another acid. It is an unstable bond. Cleavage results in the formation of multiple compounds containing an R'group with a pendant carboxylic acid group.

[Chemical 15]

Alternatively, the HNMP compound may have the following structure:

[Chemical 16] In the formula, the bond between R'and X'is such that an R- (Xc) n '(Xc is an acidic polar pendant group from R) derivative is produced by acid cleavage of the R'-X' bond, It is an acid labile bond. In the above formula, n ′ is at least 2. At least one R ′ alicyclic group, and the total of at least one R or the remaining R ′ groups consists of an acrylic group. The result after cleavage is in each case the production of two smaller molecules, each containing an alicyclic group, and the production of polar functional groups pendant from R.

When X is a carboxyl group, this structure is represented by the following formula.

[Chemical 17] After cleavage, R contains multiple (n ') carboxylic acid pendant groups. In the formula, R is a norbornyl alicyclic group,
n ′ = 2, each R ′ contains adamantane and the HNMP additive has the structure:

[Chemical 18] After cleavage, the norbornyl compound has two carboxylic acid pendant groups.

Other possible HNMP additive structures include:

[Chemical 19]

[Chemical 20]

In the HNMP used in the present invention, the acid labile linking group reacts favorably with the acid formed during the photolithography process, which results in the cleavage of the group to form a plurality of molecules and a reduction in molecular weight. Substantially reduce or enhance the solubility of the radiation exposed portions of the photoresist in aqueous alkaline solutions. Preferred acid labile linking groups are selected from the group consisting of tertiary alkyl (or cycloalkyl) carboxylic acid esters, (eg, t-butyl, methylcyclopentyl, methylcyclohexyl, methyladamantyl), ester ketals, and ester acetals. It is a thing. The HNMP component may also contain pendant groups that increase the bulk of the molecule and / or increase the hydrophobicity of the molecule so as to enhance the properties of the photoresist composition. If necessary, HNMP components may be used in combination.

Examples of preferred HNMP components include the biscarboxyl ester of adamantane and higher fused alicyclic ring structures. The most preferred HNMP component is bis adamantane t-butyl carboxylic acid.

The photoresist composition of the present invention usually contains a solvent before it is applied to the intended substrate. The solvent can be any solvent conventionally used for acid catalyzed photoresists that does not unduly adversely affect the performance of the photoresist composition. Preferred solvents are propylene glycol monomethyl ether acetate, cyclohexane, and ethyl cellosolve acetate.

The compositions of the present invention further contain minor amounts of auxiliary components well known to those skilled in the art, such as dyes / sensitizers, base additives and the like. The preferred base additive is a weak base that traps traces of acid and does not unduly adversely affect photoresist performance. Preferred base additives are tertiary alkyl amines (aliphatic or aromatic), or -t-alkyl ammonium hydroxides such as -t-butyl ammonium hydroxide (TBAH).

The photoresist composition of the present invention is preferably about 0.5 to 20% by weight (more preferably about 3-1) based on the total weight of the cyclic olefin polymer in the composition.
5% by weight) of a photosensitive acid generator. When a solvent is present, it is preferred that the entire composition contains about 50-90% by weight solvent. The composition preferably comprises about 1% by weight, based on the total weight of acid sensitive compounds.
It contains the following base additives. The photoresist composition of the present invention is preferably at least about 5% by weight, more preferably 10 to 25% by weight, most preferably about 10% by weight based on the total weight of the cyclic olefin polymer in the composition.
˜20 wt% BH additive component, or HNA additive component, HNMP additive component, or SS additive component.

The present invention is not limited to any particular method for synthesizing the cyclic olefin polymers used in the present invention. Preferably, the cyclic olefin polymer is produced by addition polymerization. Examples of suitable techniques are described in B. F. US Pat. No. 5,468,881 assigned to BF Goodrich Company and incorporated herein by reference.
No. 9 and 5,705,503.

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

The photoresist composition of the present invention comprises a cyclic olefin polymer, PAG, BH additive component, or HN.
It can be produced by combining the A, HNMP, or SS component with other desired components using conventional methods. Photoresist compositions used in photolithographic methods generally include a significant amount of solvent.

The photoresist compositions of the present invention are particularly useful in photolithography processes used to fabricate integrated circuits on semiconductor substrates. This composition is particularly useful in photolithographic processes that utilize 193 nm ultraviolet radiation. Other radiation (eg medium wavelength UV, 248 nm
If it is necessary to use deep ultraviolet rays, X-rays, electron beams, etc.), the composition of the present invention should be adjusted by adding an appropriate dye or sensitizer (if necessary) to the composition. You can The method of using the photoresist composition of the present invention in photolithography for semiconductors is described below.

Photolithography applications on semiconductors typically involve transfer of a pattern to a layer of material on a semiconductor substrate. A layer of material on a semiconductor substrate is used in the manufacturing process steps,
And may be a conductive layer of metal, an insulating layer of ceramic, a semiconductor layer, or other material, depending on the intended set of materials for the final product. In many cases, anti-reflective coating (A
RC) has been applied to the material layer before applying the photoresist layer. The ARC layer can be any conventional ARC compatible with acid catalyzed photoresists.

Typically, the solvent-containing photoresist composition is applied to the desired semiconductor substrate using spin coating or other techniques. The substrate coated with the photoresist coating is then preferably heated (pre-exposure baked) to remove the solvent and improve the adhesion of the photoresist layer. The thickness of the applied layer is preferably substantially uniform, provided that the photoresist layer is sufficiently resistant to the process of transferring the subsequent lithographic pattern to the underlying substrate material layer (usually reactive ion etching). It is preferable that it is as thin as possible. The pre-exposure baking step is preferably performed for about 10 seconds to about 15 minutes, more preferably about 15 seconds to about 1 minute. The pre-exposure bake temperature can be changed by the glass transition temperature of the photoresist. Preferably, the pre-exposure bake is performed at a temperature at least 20 ° C. below T _g .

After removing the solvent, the photoresist layer is patternwise exposed to the desired radiation (eg, 193 nm UV radiation). When using a scanning particle beam, such as an electron beam, patternwise exposure can be accomplished by scanning a beam of light across the substrate and selectively delivering the beam of light to the desired pattern. More typically, where the wavy radiation forms 193 nm ultraviolet radiation, etc.,
The pattern-wise exposure is through a mask placed on the photoresist layer. At 193 nm UV radiation, the total exposure energy is preferably about 100 millijoules / c.
m ² or less, more preferably about 50 millijoules / cm ²
Below (15 to 30 millijoules / cm ² ).

After performing the exposure according to the desired pattern,
The photoresist layer is usually baked to drive the acid catalyzed reaction more completely and increase the contrast of the exposed pattern. The baking after exposure is preferably about 100 to 175 ° C, more preferably about 125 to 16 ° C.
Perform at 0 ° C. Baking after exposure is about 30 seconds to about 5
It is preferable to perform it for a minute.

After the post-exposure bake, the photoresist layer is contacted with an alkaline solution that selectively dissolves the radiation exposed portions of the photoresist.
A photoresist structure having the desired pattern is obtained (developed). A preferred alkaline solution (developer) is
It is an aqueous solution of tetramethylammonium hydroxide. Preferably, the photoresist composition of the present invention can be developed with a conventionally used 0.26N alkaline aqueous solution. The photoresist composition of the present invention also comprises
It can also be developed with 0.14N, 0.21N, or other concentrations of aqueous alkaline solution. The resulting photoresist structure on the substrate is then typically dried to remove residual developer. The photoresist composition of the present invention generally comprises
The obtained photoresist structure has a feature that it has high etching resistance. In one example, post-silylation techniques well known to those skilled in the art can be used to enhance the etch resistance of the photoresist structure. The composition of the present invention allows the reproduction of lithographic features.

The pattern from the photoresist structure can then be transferred to the underlying substrate material (eg, ceramic, metal, or semiconductor). Typically, transfer is by reactive ion etching or some other etching technique. In reactive ion etching, the etching resistance of the photoresist layer is very important. Thus, the compositions of the present invention, and the resulting photoresist structures, include metal interconnects, contact holes or vias, isolations (such as damascene trenches or shallow trench isolations) as used in integrated circuit device design. ), And can be used to form patterned material layer structures, such as trenches for capacitor structures.

The method of forming these (ceramic, metal, or semiconductor) features typically involves the steps of providing a layer or portion of the material of the substrate on which the pattern is to be formed.
Applying a layer of photoresist over a layer or portion of the material, exposing the photoresist to radiation according to a pattern, and exposing the exposed photoresist to a solvent to develop the pattern, Forming a layer of patterned material or a portion of the substrate by etching one or more layers below the photoresist layer in the space of the pattern and removing any residual photoresist from the substrate And a step of performing. In some examples, a hard mask is used below the photoresist layer to facilitate transfer of the pattern to underlying material layers or portions. An example of such a method is US Pat. No. 4,855,017.
No. 5362663, 5429710, 55
62801, 5618751, 5744376.
Nos. 5,810,094, and 5,821,469, which patents are hereby incorporated by reference. An example of another method of transferring a pattern is Wayne Moresu, “Semiconductor Lithography, Principles, Practice, and Materials (Semiconductor
Lithography, Principles, Practices, and Material
s) ”, Plenum Press, 1988
Years, Chapters 12 and 13, the disclosures of which are hereby incorporated by reference. It should be appreciated that the present invention is not limited to any particular lithographic technique or device structure.

[0057]

EXAMPLES Experimental Example 1 (Comparative Example) For the purpose of conducting a lithography experiment, norbornene-t-
Butyl ester (NB-t-BE) 85% and norbornenecarboxylic acid (NB-CA) 1 (as a pendant group)
A photoresist formulation containing a 5% norbornene copolymer was prepared by incorporating the materials shown in the parts by weight below.

[Table 1]

This photoresist formulation was prepared by
Antireflective material coated on the wafer was spin-coated (30 seconds) and on the (ArX ^(R), Shipley Company (Shipley Company)) layer. The photoresist layer was soft-baked on a vacuum hot plate at 130 ° C. for 60 seconds to form a film having a thickness of about 0.4 μm. Next, the wafer is radiated at 193 nm (0.6 NA
It was exposed with ArF and ISI stepper). The exposure pattern was an array of lines, with different spacings of at least 0.1 μm. The exposed wafer was post-exposure baked on a vacuum hot plate at 150 ° C. for 90 seconds. Next, 0.26 of the pattern-exposed photoresist is used.
Developed (paddle) with 3N tetramethylammonium hydroxide developer. Next, the pattern was scanned with a scanning electron microscope (SE
M). According to the cross-sectional SEM pattern, it was found that the lines overlap each other, so that the L / S (line / spacing pair) of less than 200 nm is not resolved. Even line-spacing pairs over 200 nm were not completely resolved due to excessive scum / residue between the lines.

Experimental Example 2 Synthesis of tert-butyl-3-trifluoroacetyl lithocholic acid A 12-liter four-neck round bottom equipped with an upper stirrer, thermocouple temperature monitor, and constant pressure dropping funnel with nitrogen inlet. A flask was charged with 500 g (1.328 mol) of lithocholic acid and 4 liters of dry THF. Next, 1920 ml (13.6 mol) of trifluoroacetic anhydride was put into the dropping funnel. The flask was cooled with ice under a nitrogen atmosphere and trifluoroacetic anhydride was added in a thin stream keeping the temperature below 10 ° C. The mixture was allowed to warm to room temperature with stirring overnight, after which the solvent and excess trifluoroacetic anhydride were removed by rotary evaporation. The thick viscous intermediate product was returned to the 12 liter flask and an additional 4 liters of THF was added. 740 g (10 mol) of t-butyl alcohol (diluted with a small amount of THF to prevent solidification) was put in the dropping funnel. The flask is cooled again with ice and the temperature is kept below 10 ° C.
-Butyl alcohol was added in a thin stream. The mixture was allowed to come to room temperature overnight. Then solid NaHCO ₃
About 200 g was added and stirring continued for another 2 hours. Then a rotary evaporator was used to remove solvent and excess t-
Butyl alcohol was removed and the mixture was dissolved in 4 liters of ethyl ether, then carefully washed 3 times with 800 ml of saturated NaHCO ₃ solution, then washed with 1000 ml of water.
Washed twice. The solvent was dried over MgSO ₄ for 1 hour with stirring, filtered and evaporated on a rotary evaporator. The thick viscous residue was slowly eluted with hexane on a large column containing 800 g of silica gel in hexane. The product fractions were combined and evaporated on a rotary evaporator and the residual solvent was depressurized in a stream of nitrogen at 40 ° C. and removed to quantitative yield, yielding 620 g of the desired product (88% yield). Obtained as an off-white syrupy liquid. The product was crystallized with pentane at -78 ° C to give a low melting white wax.

Experimental Example 3 This experimental example illustrates the advantages of the composition of the present invention containing a saturated steroid additive. A photoresist formulation was prepared by incorporating the materials shown in the parts by weight below.

[Table 2]

This photoresist formulation was prepared by
Antireflective material coated on the wafer was spin coated onto the (ArX ^(R), Shipley Company (Shipley Company)) layer was exposed according to a pattern (193 n
m radiation) in the same manner as in Experimental Example 1. The resulting pattern was then inspected with a scanning electron microscope (SEM). Line / spacing pairs of 140 nm or more were well resolved and a clear profile was obtained. The exposure energy required for this formulation was in the range of 25-35 mJ / cm ² .

Experimental Example 4 Synthesis of adamantane-1-carboxylic acid-t-butyl ester t-butyl alcohol 2 in 600 ml of methylene chloride.
In a suspension obtained by suspending 5.34 g (0.342 mol),
At room temperature, 38.07 g (0.3815 mol) of triethylamine was added. The resulting suspension was stirred at room temperature until it became a clear solution. To the solution at 0 ° C. was added 74.75 g (0.3762 mol) of adamantane-1-carbonyl chloride. After the addition was complete, the reaction mixture was stirred at room temperature for 12 hours and then at reflux for 2 hours. The reaction mixture was filtered to remove the triethylamine hydrochloride formed during the reaction. The filtrate was washed with water (× 500 ml) several times, dried over anhydrous sodium sulfate and concentrated under reduced pressure. Purify the residue by column chromatography (silica gel, hexane / methylene chloride 9: 1) to give 48.
4 g (-60%) of white solid was obtained. This solid is
It was identified to be adamantane-1-carboxylic acid-t-butyl ester by NMR spectroscopy.

Experimental Example 5 This experimental example illustrates the advantages of the composition of the present invention containing adamantane-1-carboxylic acid-t-butyl ester. A photoresist formulation was prepared by incorporating the materials shown in the parts by weight below.

[Table 3]

This photoresist formulation was prepared by
Antireflective material coated on the wafer was spin coated onto the (ArX ^(R), Shipley Company (Shipley Company)) layer was exposed according to a pattern (193 n
m radiation) in the same manner as in Experimental Example 1. The resulting pattern was then inspected with a scanning electron microscope (SEM). Line / spacing pairs of 140 nm or more were well resolved and a clear profile was obtained. The exposure energy required for this formulation was in the range of 20-30 mJ / cm ² .

[0065] Example 6 2,5-bis 2 (adamantane-1-carboxylic oxy) -2,5-methylene chloride synthesis 600ml of dimethyl hexane, 5 - dimethyl-2,5
-76.14 g of triethylamine at room temperature in a suspension of 50 g (0.342 mol) of hexanediol
(0.762 mol) was added. The resulting suspension was stirred at room temperature until it became a clear solution. 0 ℃ to the solution
149.5 g of adamantane-1-carbonyl chloride
(0.7524 mol) was added. After the addition is complete
The reaction mixture was stirred at room temperature for 12 hours and then at reflux.
Stir for hours. The reaction mixture was filtered to remove the triethylamine hydrochloride formed during the reaction. The filtrate is water (× 50
(0 ml) several times, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, hexane / methylene chloride 9: 1) to give 128 g (-80%) of a white solid. This solid was analyzed by NMR spectroscopy to give 2,5-bis (adamantane-1-carboxyloxy) -2,5
-Identified to be dimethylhexane.

Experimental Example 7 This experimental example illustrates the advantages of the composition of the present invention containing 2,5-bis (adamantane-1-carboxyloxy) -2,5-dimethylhexane. A photoresist formulation was prepared by incorporating the materials shown in the parts by weight below.

[Table 4]

This photoresist formulation was prepared by
Antireflective material coated on the wafer was spin coated onto the (ArX ^(R), Shipley Company (Shipley Company)) layer was exposed according to a pattern (193 n
m radiation) in the same manner as in Experimental Example 1. The resulting pattern was then inspected with a scanning electron microscope (SEM). Lines / spacing pairs of 130 nm or more were well resolved and a clear profile was obtained. The exposure energy required for this formulation was in the range of 20-30 mJ / cm ² .

─────────────────────────────────────────────────── --Continued front page (31) Priority claim number 09/266344 (32) Priority date March 11, 1999 (March 11, 1999) (33) Country of priority claim United States (US) pre-screening (72) Inventor Robert Dee Allen United States 95120 San Jose, California Carre del Connejo 6186 (72) Inventor Thomas I Worrow United States 94587 Union City, CA Royal Ann Drive 2656 (72) Inventor Julian Opitz United States 95126 San Jose, California De Marietta Avenue 1670 Number 3 (72) Inventor Richard A. De Pietro United States 95120 San Jose, California Mount Holly Dora Bou 6682 (72) Inventor Margaret Sea Lawson United States 12545 Millbrook Py O'Box, New York 1348 (72) Inventor Anne-Marie Muharter United States 12590 New York Wappingers Falls Popula Boulevard 506 (72) ) Inventor Joseph F. Maniscarco United States 12449 Lake Catherine, New York Corwin Place 1 (72) Inventor Mahmoud M. Hogiste USA 12601 Pawkeepsie Martinelli Court 5 (72) Inventor George M. Jordamo United States 12533 Hopewell Junction, New York Hollibury Drive 14 (72) Inventor Hiroshi Ito United States 95120 San Jose, California Echo Ridge Dora 7149 (56) Reference JP-A-10-307401 (JP, A) JP-A-10-111569 (JP, A) JP-A-8-15865 (JP, A) JP-A-6-123970 (JP, A) ) JP 5-265214 (JP, A) JP 9-265177 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (12)

(57) [Claims] 1. (a) Norbornene-t-butyl ester
(NB-t-BE) and norbornenecarboxylic acid (NB-
CA) -containing norbornene copolymer , (b) photosensitive acid generator, and (c) t-butyl-3-trifluoroacene.
Cetyl lysocholate, adamantane-1-carboxylic acid-
t-butyl ester, and 2,5-bis (adamanta
1-carboxyloxy) -2,5-dimethylhexyl
A photoresist composition comprising a substantially transparent, bulky hydrophobic additive selected from the group consisting of sun . 2. The composition according to claim 1, comprising 5 to 25 % by weight of the hydrophobic additive, based on the weight of the norbornene copolymer . 3. The norbornene copolymer is 10 to 80.
Mol% norbornenecarboxylic acid (NB-CA) , 2
0-90 mol% norbornene-t-butyl ester
The composition according to claim 1, which comprises (NB-t-BE) . 4. A patterned photoresist structure on a substrate, wherein the photoresist is (a) norvol.
Nene-t-butyl ester (NB-t-BE) and norbo
Norbornene containing runenecarboxylic acid (NB-CA)
Copolymer , (b) a photosensitive acid generator, and (c) t-butene
Chill-3-trifluoroacetyl lysocholate, Adama
Tan-1-carboxylic acid-t-butyl ester, and
2,5-bis (adamantan-1-carboxyl oki
Si) A photoresist structure comprising a substantially transparent, bulky hydrophobic additive selected from the group consisting of -2,5-dimethylhexane . 5. A method of forming a patterned photoresist structure on a substrate, comprising: (A) adding norbornene-t-butyl ester to the substrate.
Tell (NB-t-BE) and norbornenecarboxylic acid (N
B-CA) -containing norbornene copolymer , (b)
A photosensitive acid generator, and (c) t-butyl-3-trifluor
Roacetyl lysocholate, adamantane-1-carvone
Acid-t-butyl ester, and 2,5-bis (adamama
Tan-1-carboxyloxy) -2,5-dimethyl
Applying a photoresist composition comprising a substantially transparent, bulky hydrophobic additive selected from the group consisting of hexane to form a photoresist layer on the substrate; Exposing the substrate to radiation in a pattern-wise manner to generate an acid by the photosensitive component in the areas of the photoresist layer exposed to the radiation; and (C) contacting the substrate with an aqueous alkaline developer. Selectively dissolving the exposed areas of the photoresist layer with the developer to form a patterned photoresist structure on the substrate. 6. The radiation used in step (B) is 2
The method according to claim 5 , wherein the ultraviolet radiation is shorter than 50 nm. 7. The method of claim 5 , further comprising the step of baking the substrate between steps (B) and (C). 8. A method of forming a structure of patterned material on a substrate, wherein the material is selected from the group consisting of semiconductors, ceramics and metals, (A) a layer of the material. And (B) forming norbornene-t-butyl ester on the substrate.
Tell (NB-t-BE) and norbornenecarboxylic acid (N
B-CA) -containing norbornene copolymer , (b)
A photosensitive acid generator, and (c) t-butyl-3-trifluor
Roacetyl lysocholate, adamantane-1-carvone
Acid-t-butyl ester, and 2,5-bis (adamama
Tan-1-carboxyloxy) -2,5-dimethyl
Applying a photoresist composition comprising a substantially transparent, bulky hydrophobic additive selected from the group consisting of hexane to form a photoresist layer on the substrate; Exposing the substrate to radiation in a pattern-wise manner to generate acid in the areas of the photoresist layer exposed to the radiation by the photosensitive component; and (D) contacting the substrate with an aqueous alkaline developer. By selectively dissolving the exposed region of the photoresist layer with the developing solution to form a patterned photoresist structure on the substrate, and (E) etching the pattern of the photoresist structure, Transferring to a layer of the material through spaces in the pattern of the photoresist structure. 9. The method of claim 8 , wherein the etching is performed by reactive ion etching. 10. At least one intermediate layer is provided between the layer of material and the photoresist layer, step (E).
9. The method of claim 8 including the step of etching through the intermediate layer. 11. The method of claim 8 , wherein the radiation has a wavelength less than 250 nm. 12. The method of claim 8 , wherein the substrate is baked between steps (C) and (D).