JP2008162952A - Photosensitive composition, compound and resin usable therefor, and pattern-forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive composition, especially the photosensitive composition suitable for a double-layered or a multilayered resist, to provide a resin suitable for the photosensitive composition, and a compound suitable for the production of the resin, and to provide a pattern-forming method using the composition. <P>SOLUTION: The photosensitive composition contains (A) a resin containing a specific siloxane unit having a group leaving by the decomposition by the action of an acid, and enabling a dissolving rate in an alkali developing liquid to be increased by the action of the acid, and (B) a compound generating the acid by the irradiation with an active ray or a radial ray. The resin, the compound suitable for the production of the resin, and the pattern-forming method using the composition are also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a positive photoresist composition for microfabrication of semiconductor elements and the like which is sensitive to far ultraviolet rays, and more particularly, deep ultraviolet rays for performing high-resolution photolithography, particularly 193 nm and 243 nm bilayer resists. The present invention relates to a positive photoresist composition for deep ultraviolet exposure useful in a system.

  In response to the demand for higher density and higher integration of LSIs (highly integrated circuits), it is necessary to develop photoresists that can form finer patterns. In general, improvements in photoresist resolution, photospeed, depth of focus, and other properties are required. Resolution improvements can also be made by exposure systems that utilize a larger numerical aperture. Unfortunately, as the resolution is improved by a larger numerical aperture, the depth of focus at the best resolution usually decreases due to optical effects. Therefore, improving the depth of focus of the resist is also desirable.

  The most common resist is referred to as a “single layer” where the resist has both imaging and plasma etch resistance functions. The second type of resist is referred to as a “two-layer resist” in which the image forming function is assigned to the top layer and the plasma etch resistance function is assigned to the lower layer. In the oxygen etch stage, the imaged pattern is transferred to the lower layer. Bilayer resists provide certain advantages in resolution because they generally contain silicon and use thinner imaging films, and in many cases, bilayer resist / undercoat combinations provide better substrate plasma etch resistance. Bring. Examples of the bilayer resist are disclosed in Patent Documents 1 to 3, for example.

Polysiloxane polymers are excellent in dry etching resistance, and some examples are already used for resist materials. For example, Patent Document 4 discloses a polymer in which a carboxyl group of poly (2-carboxyethylsiloxane) is protected by a group (acid decomposable group) that is decomposed by the action of an acid such as a t-butyl group and dissolved in an alkali developer. The positive resist used is disclosed. However, resist materials using these siloxane polymers are not sufficient in terms of basic physical properties as resists such as transparency to actinic rays or radiation, resolution, and developability, and further improvements have been demanded.
Furthermore, Patent Document 5 has a non-aromatic monocyclic or polycyclic hydrocarbon group or bridged cyclic hydrocarbon group having a carboxyl group in the side chain, and at least a part of the carboxyl group. Siloxane polymers substituted with an acid labile group, such as siloxane polymers in which a norbornyl group having a t-butoxycarbonyl group at the 5-position is bonded to a silicon atom, and resist materials using the polymers are disclosed. This resist material is said to have low absorption of KrF excimer laser (wavelength 248 nm) or ArF excimer laser (wavelength 193 nm), good pattern shape, and excellent sensitivity, resolution, dry etching resistance, etc. ing. In Patent Document 6, a resist containing a specific siloxane-based polymer having a norbornene-based alicyclic structure having one carboxyl group as a substituent is used to form a pattern using radiation such as far-ultraviolet rays, electron beams, and X-rays. Are disclosed as useful.

However, even if these siloxane polymers described in Patent Document 5 and Patent Document 6 are included, there are few types of siloxane polymers useful as the resin component of the resist material. The development of photosensitive compositions that are sensitive to radiation, have high dry etching resistance, and have excellent basic physical properties as resists is important from the viewpoint of technological development that can respond to the progress of miniaturization in semiconductor devices. It has become a challenge.
US Pat. No. 6,359,078 US Pat. No. 5,985,524 US Pat. No. 6,028,154 JP-A-8-160623 Japanese Patent No. 3533951 Japanese Patent Laid-Open No. 2002-278073

  An object of the present invention is to provide a photosensitive composition that is effectively sensitive to short-wavelength radiation, has high dry etching resistance, and has excellent basic physical properties as a resist, and particularly suitable for a two-layer or multilayer resist. It is to provide a sex composition. Moreover, the further subject of this invention is providing the resin suitable for the photosensitive composition, and the compound suitable for manufacture of this resin.

  The object of the present invention has been achieved by the following <1> to <9>.

<1> (A) a resin having a structural unit represented by general formula (I), which increases the dissolution rate in an alkaline developer by the action of an acid, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation, A photosensitive composition comprising:

In general formula (I),
A represents a polycyclic hydrocarbon group. Q represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X ¹ and X ² each independently represent a group that decomposes and leaves by the action of an acid.

<2> The photosensitive composition as described in <1> above, wherein the resin (A) further has a structural unit represented by the formula (II).

<3> The photosensitive composition as described in <1> or <2> above, wherein A in the general formula (I) is a polycyclic hydrocarbon group represented by the general formula (III).

In general formula (III):
m shows the integer of 0-3.
P ₁ represents a bond with a Si atom in the general formula (I).
P ₂ represents a bond with —COOX ₁ and —COOX ₂ in the general formula (I).

<4> The photosensitive composition according to <3>, wherein m in the general formula (III) is 0.

<5> In any one of the above items <1> to <4>, wherein X ¹ and X ² in the general formula (I) are groups capable of decomposing and leaving by the action of an acid represented by the following general formula (IV) The photosensitive composition as described.

In formula ^(IV), R 1 ~R ³ is an alkyl group or a cycloalkyl group each independently. R ² and R ³ may combine to form a ring.

<6> including a step of forming a second resist layer on the substrate provided with the first resist layer with the photosensitive composition according to any one of the above <1> to <5>, exposing and developing the resist layer. The pattern formation method characterized by the above-mentioned.

<7> A compound represented by the general formula (V).

In general formula (V):
A represents a polycyclic hydrocarbon group.
Q represents an alkyl group, a cycloalkyl group, or an aryl group.
X ¹ and X ² each independently represents an organic group that is decomposed by the action of an acid to generate a group that dissolves in an alkaline developer.
R ⁴ and R ⁵ each independently represents an alkoxy group.
<8> A compound represented by the general formula (V), wherein A in the general formula (V) is a polycyclic hydrocarbon group represented by the general formula (III).

In general formula (III), m shows the integer of 0-3.
P ₁ represents a bond to Si atoms in the general formula (I).
P ₂ represents a bond with —COOX ₁ and —COOX ₂ in the general formula (I).
<9> Resin (A) having the compound represented by the general formula (V) as one of polymerization components.

According to the present invention, a photosensitive composition that effectively responds to short-wavelength radiation, has high dry etching resistance, and has excellent basic physical properties as a resist, particularly suitable for a two-layer or multilayer resist. Things can be provided. In particular, the polycyclic hydrocarbon group of the resin whose dissolution rate in an alkaline developer is increased by the action of the acid of the present invention has a plurality of groups that generate a carboxylic acid group by the action of an acid upon irradiation with actinic rays or radiation. Therefore, sensitivity or dry etching resistance can be increased.
Moreover, the polymer (siloxane polymer) suitable for the photosensitive composition by this invention and the compound (silyl monomer) suitable for manufacture of this siloxane polymer can be provided.

Below, the photosensitive composition of this invention is demonstrated in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

<(A) Siloxane resin having a structural unit represented by general formula (I) and whose dissolution rate in an alkaline developer is increased by the action of an acid>
The photosensitive composition of the present invention comprises (A) a siloxane resin having a structural unit represented by the general formula (I) and having a dissolution rate in an alkali developer increased by the action of an acid (both the (A) component and the resin (A)). Contain).

In general formula (I),
A represents a polycyclic hydrocarbon group.
Q represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group. Q is preferably an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Specifically, a methyl group, an ethyl group, or a phenyl group is preferable.
X ¹ and X ² each independently represent an organic group that decomposes by the action of an acid to generate a group that dissolves in an alkaline developer.

Resin (A) is a resin (acid-decomposable resin) that is decomposed by the action of an acid and has increased solubility in an alkali developer, and the main chain or side chain of the resin, or both the main chain and side chain, It is a resin having a group that decomposes under the action of an acid to generate an alkali-soluble group (hereinafter also referred to as “acid-decomposable group”).
Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) Imido group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group A group having
Preferred alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferred group as an acid-decomposable group (acid-decomposable group) is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.
Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

In the general formula (I), X ¹ and X ² each independently represent a group that decomposes and leaves by the action of an acid. Specific examples include the above-described groups leaving with an acid.

As X ¹ and X ² , an organic group represented by the following general formula (IV) is particularly preferable.

In the general formula (IV), R ^{1 to} R ³ each independently represents an alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms), and R ² and R ³ are They may combine to form a ring.
Here, the alkyl group may be a linear or branched alkyl group. The cycloalkyl group may be a monocyclic or polycyclic alkyl group.
R ¹ is preferably a linear alkyl group having 1 to 6 carbon atoms, particularly preferably a linear alkyl group having 1 to 3 carbon atoms. Specifically, a methyl group, an ethyl group, and a propyl group can be given as particularly preferred examples.
R ² and R ³ are preferably an alkyl group or cycloalkyl group having 20 or less carbon atoms, preferably a linear alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms. Specifically, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and an adamantyl group can be mentioned as particularly preferred examples.
R ² and R ³ are also preferably bonded to form a ring, and R ² and R ³ are preferably bonded to form an alicyclic ring having 5 to 20 carbon atoms. It is particularly preferred to form 12 alicyclic rings. It is particularly preferable to form cyclopentane, cyclohexane or adamantane as the alicyclic ring.
R ^{1 to} R ³ may further have a substituent. Examples of preferable substituents include alkyl groups having 1 to 6 carbon atoms, and a methyl group is particularly preferable.

  In general formula (I), the polycyclic hydrocarbon group represented by A is preferably a polycyclic hydrocarbon group having 7 to 20 carbon atoms, and preferably a polycyclic hydrocarbon group having 7 to 12 carbon atoms. Particularly preferred. The polycyclic hydrocarbon group represented by A may have a substituent. Preferred examples of the substituent include an alkyl group having 1 to 6 carbon atoms, and a methyl group is particularly preferable.

  More specifically, the polycyclic hydrocarbon group represented by A is particularly preferably a polycyclic hydrocarbon group represented by the general formula (III).

In general formula (III):
m shows the integer of 0-3. m is preferably an integer of 0 to 2, m is more preferably 0 or 1, and particularly preferably 0.
P ₁ represents a bond with a Si atom in the general formula (I).
P ₂ represents a bond with —COOX ₁ and —COOX ₂ in the general formula (I).
When m is 2 or 3, P ₁ may be bonded from any carbon atom constituting the polycycle.

  The resin (A) preferably further has a structural unit represented by the formula (II).

  Specific examples of the resin (A) include the following.

The resin (A) is a polymer containing the structural unit represented by the general formula (I) and optionally the formula (II) or other structural units. It may be dimensional (three-dimensional). That is, for example, a cage-type polysilsesquioxane resin or a ladder-type polysilsesquioxane resin may be used.

The resin (A) of the present invention polymerizes a silyl monomer compound represented by the general formula (V) and a monomer compound that optionally forms other structural units such as the structural unit represented by the general formula (II). It is obtained by.
The compound represented by the general formula (V) of the present invention will be described below.

In the general formula (V), A, Q, X ¹ and X ² have the same meanings as in the general formula (I). R ⁴ and R ⁵ each represent an alkoxy group, preferably an alkoxy group having 1 to 20 carbon atoms, more preferably a linear alkoxy group having 1 to 6 carbon atoms, and particularly preferably a linear chain having 1 to 3 carbon atoms. An alkoxy group; Specifically, a methyl group, an ethyl group, and a propyl group are particularly preferable examples.

  The compound represented by the general formula (V) can be synthesized, for example, by the following method.

<Step 1>
Using C-1 as a starting material, X ¹ —OH and X ² —OH are reacted in the presence of a base to convert to C-2. In C-1, B corresponds to the unsaturated body of A in the general formula (V). L ¹ and L ² each represent a leaving group, and preferred examples include halides such as chlorine and bromine, substituted sulfonyl groups such as mesyl and tosyl groups, and halides such as chlorine and bromine are particularly preferred. As an example. At this time, the base to be used may be either an inorganic base or an organic base. An example of a particularly preferable inorganic base is t-butoxy potassium, and an example of a particularly preferable organic base is DBU.

  As the solvent used for the polycondensation reaction, linear or branched ketones, cyclic ketones, esters, ethers, alcohols, and hydrocarbons can be used. Specifically, methyl ethyl ketone, cyclohexyl ketone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, n-propyl alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, tetrahydrofuran, Examples include toluene and xylene. These solvents can be used alone or in admixture of two or more. The usage-amount of a solvent is 200 mass parts or less normally with respect to the compound shown by the said general formula (V).

The reaction temperature is usually −50 to + 300 ° C., preferably 20 to 150 ° C. , and the reaction time is usually about 1 minute to 100 hours, preferably 30 minutes to 48 hours.

<Process 2>
C-2 and C-3 are dissolved in a solvent and then reacted in the presence of a catalyst to produce a compound of the general formula (V) of the present invention. In C-3, R ⁴ , R ⁵ , and Q are as defined above. As a catalyst to be used, for example, a rhodium catalyst can be used.
As the solvent used for the polycondensation reaction, linear or branched ketones, cyclic ketones, esters, ethers, alcohols, and hydrocarbons can be used. Specifically, methyl ethyl ketone, cyclohexyl ketone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, n-propyl alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, tetrahydrofuran, Examples include toluene and xylene. These solvents can be used alone or in admixture of two or more. The usage-amount of a solvent is 200 mass parts or less normally with respect to the compound shown by the said general formula (V).

  The reaction temperature is usually −50 to + 300 ° C., preferably 20 to 150 ° C., and the reaction time is usually about 1 minute to 100 hours, preferably 30 minutes to 48 hours.

The production of the siloxane resin of the present invention will be described below.
The siloxane resin of the present invention can be produced by polycondensing the compound represented by the general formula (V) by a conventional method in the absence of a solvent or a solvent in the presence of an acidic catalyst or a basic catalyst.

  Specific examples of the acidic catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, titanium tetrachloride, zinc chloride, and aluminum chloride. Organic acids such as fluoroacetic acid, n-propionic acid, butyric acid, citric acid, benzenesulfonic acid, p-toluenesulfonic acid and methanesulfonic acid can be used. These acidic catalysts may be used alone or in admixture of two or more.

  Specific examples of the basic catalyst include inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, and potassium carbonate. Can be used.

  Further, for example, linear, branched or cyclic monoalkylamines, dialkylamines, trialkylamines and aromatic amines can be used. In addition to imidazoles, pyridines; piperazines, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2 .2] Other nitrogen-containing heterocyclic compounds such as octane can be used. These basic catalysts may be used alone or in admixture of two or more.

  Of the acidic catalyst and basic catalyst, hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, acetic anhydride, triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine and the like are preferable, and trifluoroacetic acid is particularly preferable. The usage-amount of an acidic catalyst or a basic catalyst is 0.01-1000 mass parts normally with respect to the compound shown by the said general formula (V), Preferably it is 0.1-100 mass parts.

As the solvent used for the polycondensation reaction, linear or branched ketones, cyclic ketones, esters, ethers, alcohols, and hydrocarbons can be used. Specifically, methyl ethyl ketone, cyclohexyl ketone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, n-propyl alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, tetrahydrofuran, Examples include toluene and xylene. These solvents can be used alone or in admixture of two or more. The usage-amount of a solvent is 200 mass parts or less normally with respect to the compound shown by the said general formula (V).

  In the polycondensation reaction, water can be added to the reaction system. The amount of water added in this case is usually 1000 parts by mass or less with respect to the compound represented by the general formula (V).

  Furthermore, in the polycondensation for producing the siloxane resin of the present invention, it is preferable to mix and use a silane compound together with the compound represented by the general formula (V). Preferred examples of the silane compound include a tetraalkoxysilane compound, an alkyltrialkoxysilane compound, a dialkyldialkoxysilane compound, and a trialkylalkoxysilane compound, which constitute the structural unit represented by the general formula (II). It is particularly preferable to use a silane compound. More specifically, silane compounds such as tetramethoxysilane, tetraethoxysilane, and tetrapropylsilane can be given as particularly preferable examples.

  Hexamethyldisiloxane can be added to control the molecular weight of the resulting resin and improve the stability of the resulting polymer. The addition amount of hexamethyldisiloxane is usually 500 parts by mass or less, preferably 50 parts by mass or less, with respect to 100 parts by mass of the total amount of the silane compound. In this case, when the addition amount of hexamethyldisiloxane exceeds 500 parts by mass, the molecular weight of the obtained polymer tends to be small, and the glass transition temperature (Tg) tends to decrease. The reaction temperature in the polycondensation reaction is usually −50 to + 300 ° C., preferably 20 to 150 ° C., and the reaction time is usually about 1 minute to 100 hours, preferably 30 minutes to 48 hours.

In the siloxane resin of the present invention, the total content of the structural unit (I) is usually 1 to 100 mol%, preferably 10 to 100 mol%, particularly preferably 20 to 100 mol%, based on all structural units. is there.
The total content of the structural units represented by the general formula (II) is usually 0.1 to 30 mol%, preferably 1 to 25 mol%, particularly preferably 5 to 20 mol%, based on all structural units. is there.

In the siloxane resin of the present invention, the polystyrene-equivalent weight average molecular weight (hereinafter referred to as “Mw”) measured by gel permeation chromatography (GPC) is 500 to 1,000,000, preferably 500 to 500,000, Especially preferably, it is 1,000-100,000. In this case, if the Mw is less than 500, the glass transition temperature of the resulting polymer tends to decrease, whereas if it exceeds 1,000,000, the solubility of the resulting polymer in the solvent tends to decrease.
Moreover, glass transition temperature (Tg) is -50- + 500 degreeC normally, Preferably it is 0-300 degreeC. In this case, if the glass transition temperature (Tg) is less than −50 ° C., pattern formation tends to be difficult when a resist material is used. On the other hand, if the glass transition temperature (Tg) exceeds 500 ° C., the solubility of the resulting polymer in a solvent is poor. There is a tendency to decrease.

In the present invention, the amount of the resin (A) used is usually in the range of 99.99 to 70% by mass, preferably 99.9 to 75% by mass, more preferably, based on the solid content in the composition. Is used in the range of 99 to 85% by mass.
In this invention, a siloxane resin can be used individually or in mixture of 2 or more types. In this case, the total amount of the siloxane resin containing the resin (A) is usually used in the range of 99.99 to 70% by mass, preferably 99.9 to 75% by mass, based on the solid content in the composition. %, More preferably 99 to 85% by mass.

(B) Compound that generates acid upon irradiation with actinic ray or radiation The photosensitive composition of the present invention is a compound that generates acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”). contains.
As the acid generator used in the present invention, a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecoloring agent for dyes, a photochromic agent, a microresist, etc. Acid (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam or ion beam. The generated compounds and mixtures thereof can be appropriately selected and used.

Other acid generators used in the present invention include, for example, onium salts such as diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, organic halogen compounds, and organic metal / organic halogens. Compound, an acid generator having an o-nitrobenzyl type protecting group, a compound capable of generating a sulfonic acid by photolysis represented by iminosulfonate, a disulfone compound, a diazoketosulfone, a diazodisulfone compound, and the like. .
In addition, a group in which an acid is generated by light or a compound in which a compound is introduced into the main chain or side chain of a polymer can be used.

Furthermore, VNR Pillai, Synthesis, (1), 1 (1980), A. Abad et al., Tetrahedron
Lett., (47) 4555 (1971), DHR Barton et al., J. Chem. Soc., (C), 329 (1970), US Patent 3,779,778, European Patent 126,712, etc. Compounds that generate acids can also be used.

Among the acid generators (B), those that are particularly effective will be described in the following <A-1> to <A-4>.
<A-1>: An oxazole derivative represented by the following general formula (PAG1) substituted with a trihalomethyl group or an S-triazine derivative represented by the following general formula (PAG2).

In the formula, R ²⁰¹ represents an aryl group or an alkenyl group, and R ²⁰² represents an aryl group, an alkenyl group, an alkyl group, or —C (Y) ₃ . Y represents a chlorine atom or a bromine atom.
Specific examples include the following compounds, but are not limited thereto.

<A-2>: An iodonium salt represented by the following general formula (PAG3) or a sulfonium salt represented by the general formula (PAG4).

In the formula, Ar ¹ and Ar ² each independently represents an aryl group. R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represents an alkyl group or an aryl group.
Z ⁻ represents a counter anion, for example, perfluoroalkanesulfonic acid anions such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , camphor, etc. Alkyl sulfonate anions such as sulfonate anion, aromatic sulfonate anions such as pentafluorobenzene sulfonate anion, benzene sulfonate anion, triisopropylbenzene sulfonate anion, condensed polynuclear aromatic sulfones such as naphthalene-1-sulfonate anion An acid anion, an anthraquinone sulfonic acid anion, a sulfonic acid group-containing dye, and the like can be mentioned, but are not limited thereto. These anionic species may further have a substituent.
Two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.
Specific examples include the following compounds, but are not limited thereto.

The above onium salts represented by the general formula (PAG3) or (PAG4) are known, for example, JW Knapczyk et al., J. Am. Chem. Soc., 91, 145 (1969), AL Maycok et al., J. Org. Chem., 35, 2532, (1970), E. Goethas et al., Bull.
Soc. Chem. Belg., 73, 546, (1964), HM Leicester, J. Ame. Chem. Soc.,
51, 3587 (1929), JV Crivello et al., J. Polym. Chem. Ed., 18, 2677 (1980), U.S. Pat.Nos. 2,807,648 and 4,247,473, JP-A-53-101,331, etc. It can be synthesized by the method.

<A-3>: A disulfone derivative represented by the following general formula (PAG5) or an iminosulfonate derivative represented by the general formula (PAG6).

Wherein, Ar ³ and Ar ⁴ each independently represents an aryl group. R ²⁰⁶ represents an alkyl group or an aryl group. A represents an alkylene group, an alkenylene group, or an arylene group.

  Specific examples include the following compounds, but are not limited thereto.

<A-4>: A diazodisulfone derivative represented by the following general formula (PAG7).

In the formula, R represents an alkyl group, a cycloalkyl group, or an aryl group.
Specific examples include the following compounds, but are not limited thereto.

In this invention, an acid generator may be used individually by 1 type, or may be used in combination of 2 or more types.
The addition amount (total amount) of the acid generator is usually used in the range of 0.001 to 40% by mass, preferably 0.01 to 20% by mass, more preferably 0. 0% by mass, based on the solid content in the composition. It is used in the range of 1 to 10% by mass.

  Various additives can be added to the photosensitive composition of the present invention as necessary.

<Solvent>
Solvents that can be used in preparing the photosensitive composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, alkyl alkoxypropionate, Examples thereof include organic solvents such as cyclic lactones having 4 to 10 carbon atoms, monoketone compounds having 4 to 10 carbon atoms which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, and alkyl pyruvate.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ- Caprolactone, γ-octanoic lactone, and α-hydroxy-γ-butyrolactone are preferred.

  Examples of the monoketone compound having 4 to 10 carbon atoms which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4- Methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2 -Hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4 -Heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5- Xen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopenta Non, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcyclo Preferred are heptanone and 3-methylcycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

  It is preferable that solid content of the photosensitive composition of this invention melt | dissolves in the said solvent, and dissolves 3-40 mass% as solid content concentration. More preferably, it is 5-30 mass%, More preferably, it is 7-20 mass%.

Basic Compound The photosensitive composition of the present invention preferably contains a basic compound in order to reduce the change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.

About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) to (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically triphenylsulfonium hydroxide, tris (t-butylphenyl) sulfonium. Examples thereof include hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.
These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of a photosensitive composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

Surfactant The photosensitive composition of the present invention preferably further contains a surfactant, and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, fluorine atom and silicon). It is more preferable to contain any one or two or more of surfactants having both atoms.

When the photosensitive composition of the present invention contains the above-mentioned surfactant, it provides a resist pattern with less sensitivity and development defects with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. Is possible.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.
Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 and 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176 and F189. , F113, F110, F177, F120, R08 (manufactured by Dainippon Ink & Chemicals, Inc.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (manufactured by Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toa Gosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204D, 208G, 218G, 230G, 204D, 208D, 212D, 218, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  (F) The usage-amount of surfactant becomes like this. Preferably it is 0.01-10 mass% with respect to the photosensitive composition whole quantity (except a solvent), More preferably, it is 0.1-5 mass%.

Carboxylic acid onium salt The photosensitive composition in this invention may contain carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, as the carboxylic acid onium salt, an iodonium salt and a sulfonium salt are preferable. Furthermore, it is preferable that the carboxylate residue of the carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluoro-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass, based on the total solid content of the composition. %.

  Pattern Forming Method The method for producing a patterned image on the substrate of the present invention can be obtained, for example, by the following method.

  The photosensitive composition of the present invention is preferably prepared by preparing a solution with a solvent for the purpose of removing foreign substances and the like, and then usually filtering it with a filter having a diameter of about 0.05 to 0.2 μm.

  If necessary, the photosensitive composition of the present invention may further include an acid-decomposable dissolution inhibiting compound, a plasticizer, a photosensitizer, a crosslinking agent, a photobase generator, a thermal base generator, a spectral sensitizer, a light. Absorbent, alkali-soluble resin, and a compound that promotes solubility in a developer (for example, a phenol compound having a molecular weight of 1000 or less, an alicyclic or aliphatic compound having a carboxyl group), a compound whose basicity is reduced by exposure ( Photobase), and the like.

  Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to methods described in, for example, JP-A-4-1222938, JP-A-2-28531, U.S. Pat. No. 4,916,210, European Patent 219294, and the like. Can be easily synthesized.

  Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  As the acid-decomposable dissolution inhibiting compound that can be used in the photosensitive composition of the present invention, for example, low-molecular acid-decomposable dissolution inhibiting compounds described in JP-A Nos. 5-134415 and 6-51519 can be used. it can.

  The photosensitive composition of the present invention is preferably pre-coated on a substrate (eg, silicon / silicon dioxide coating), glass, ceramics, metal, or the like used in the manufacture of precision integrated circuit elements. Used as a second layer resist to be coated on the first layer resist. The layer formation of the photosensitive composition of the present invention is performed by dissolving each component in a solvent and applying the obtained solution by a spin coat method, a spray method or the like.

The developer for the second resist layer used in the present invention includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine and the like. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethyl An aqueous solution of an alkali such as a quaternary ammonium salt such as ammonium hydroxide, or a cyclic amine such as pyrrole or piperidine can be used.
Furthermore, an appropriate amount of alcohol, surfactant, aromatic hydroxyl group-containing compound or the like can be added to the alkaline aqueous solution. Of these, tetramethylammonium hydroxide is most preferably used.

  As the first layer resist, an appropriate organic polymer film is used, but various known photoresists may be used. For example, the FH series, FHi series, or Sumitomo Chemical PFI series manufactured by FUJIFILM Electronics Materials Corporation can be exemplified.

  In order to use the photosensitive composition of the present invention, first, a first resist layer is formed on a substrate. This layer is formed by dissolving the compound contained in the first resist layer in an appropriate solvent and applying the resulting solution by a spin coating method, a spray method or the like. The film thickness of the first resist layer is preferably 0.1 to 2.0 μm, more preferably 0.2 to 1.5 μm, and particularly preferably 0.25 to 1.2 μm.

Next, the second resist layer is formed using the resist composition of the present invention, but before that, the first resist layer is preferably heat-treated. As temperature of heat processing, 150-250 degreeC is preferable, Furthermore, 170-240 degreeC is preferable, and 180-230 degreeC is especially preferable. This heat treatment can be performed using an apparatus such as a hot plate or a heat oven.
Moreover, although the time of heat processing changes with the said heat processing temperature, it is preferable to set to the range of 10 second-1000 second, and also 20-600 second is more preferable.

Next, the second resist layer is formed on the first resist layer using the photosensitive composition of the present invention, and can be performed in the same manner as the formation of the first resist layer.
The baking temperature after coating is usually 60 to 150 ° C, preferably 90 to 130 ° C.
The film thickness of the second resist layer is preferably 0.03 to 0.6 μm, more preferably 0.04 to 0.5 μm, and particularly preferably 0.05 to 0.45 μm.

The obtained two-layer resist is then subjected to a pattern formation step. As a first step, the second layer resist composition is first subjected to pattern formation processing. Mask alignment is performed as necessary, and high energy rays are irradiated through the mask to make the irradiated resist composition soluble in an alkaline aqueous solution and developed with the alkaline aqueous solution to form a pattern. For irradiation with high energy rays, in addition to far ultraviolet rays such as KrF excimer laser (wavelength 248 nm) or ArF excimer laser (wavelength 193 nm), radiation such as extreme ultraviolet rays (EUV), electron beams, and X-rays can be used.
The development time of the second layer (upper layer) is usually 10 to 100 seconds, preferably 20 to 60 seconds.

Next, dry etching is performed as a second stage, and this operation is performed by oxygen plasma etching using the resist composition film pattern as a mask to form a fine pattern having a high aspect ratio. The etching of the organic polymer film by the oxygen plasma etching is exactly the same technique as the plasma etching used when the resist film is peeled off after completion of the etching process of the substrate by the conventional photoetching operation. This operation can be performed, for example, by a cylindrical plasma etching apparatus using oxygen as a reactive gas, that is, an etching gas. A gas such as sulfurous acid gas may be mixed with oxygen gas.
The resist of the present invention can also be suitably used for immersion lithography.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Synthesis Example 1]
Synthesis example of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester 300 g of THF was added to 28 g of t-butoxypotassium, and 25 g of 5-norbornene-2, 3-dicarboxylic acid chloride was added dropwise. After completion of the dropwise addition, the mixture was stirred for 4 hours under reflux, and ice water was added. The reaction solution was extracted with ethyl acetate, washed with brine, and the organic layer was dried over sodium sulfate. After evaporating the solvent under reduced pressure, the residue was purified by silica gel chromatography (eluent: ethyl acetate / hexane = 1/9) to obtain 23 g of 5-norbornene-2,3-dicarboxylic acid di-t-butyl ester.

The obtained 5-norbornene-2,3-dicarboxylic acid t-butyl ester (14.7 g) was dissolved in 70 mL of toluene, 50 mg of rhodium complex was added with stirring, and then 13 mL at an external temperature of 100 ° C. Of methyldiethoxysilane was added dropwise. After reacting for 4 hours, the reaction solution was filtered, and the filtrate was distilled off under reduced pressure. The residue was purified by neutral silica gel chromatography (eluent: ethyl acetate / hexane = 1/10) to obtain 18 g of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester. It was.
FABMS: m / z = 429

[Synthesis Example 2]
Synthesis example of 5- (phenyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester In Synthesis Example 1, methyldiethoxysilane was replaced with phenyldiethoxysilane, and the rest was synthesized in the same manner. (Phenyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester was obtained.
FABMS: m / z = 491

[Synthesis Example 3]
3- (Methylethoxysilyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodecane-8,9 Synthesis Example Synthesis Example 1 of dicarboxylic acid t- butyl ester, 5-norbornene-2,3-dicarboxylic acid chloride tetracyclo [4.4.0.1 ^{2, 5} . 1 ^{7, 10} ] dodec-3-ene-8,9-dicarboxylic acid chloride and then synthesized in the same manner to produce 3- (methylethoxysilyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane-8,9-dicarboxylic acid di-t-butyl ester was obtained.
FABMS: m / z = 495

[Synthesis Example 4]
Synthesis example of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1-methylcyclohexyl) ester To 23 g of 1-methylcyclohexanol, 300 mL of THF was added, and 20 g of triethylamine was added. Below, 24 g of 5-norbornene-2,3-dicarboxylic acid chloride was added dropwise. After completion of the dropwise addition, the mixture was stirred for 4 hours under reflux, and ice water was added. The reaction solution was extracted with ethyl acetate and washed with brine, and then the organic layer was dried over magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by silica gel chromatography (eluent: ethyl acetate / hexane = 2/8) to obtain 20 g of 5-norbornene-2,3-dicarboxylic acid di (1-methylcyclohexyl) ester. It was.

The obtained 5-norbornene-2,3-dicarboxylic acid di (1-methylcyclohexyl) ester (19 g) was dissolved in 70 mL of toluene, 50 mg of rhodium complex was added with stirring, and then the external temperature was raised to 100 ° C. 13 mL of methyldiethoxysilane was added dropwise. After reacting for 4 hours, the reaction solution was filtered, and the filtrate was distilled off under reduced pressure. The residue was purified by neutral silica gel chromatography (eluent: ethyl acetate / hexane = 1/10) and 12 g of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1-methylcyclohexyl). An ester was obtained.
FABMS: m / z = 509

[Synthesis Example 5]
Synthesis example of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1-methylcyclopentyl) ester In Synthesis Example 4, 1-methylcyclohexanol was replaced with 1-methylcyclopentanol, and the same 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1-methylcyclopentyl) ester was synthesized.
FABMS: m / z = 481

[Synthesis Example 6]
Synthesis example of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1,1-dimethyl-1- (4-methylcyclohexyl) methyl) ester In Synthesis Example 4, 1-methylcyclohexanol was changed to 1 , 1-dimethyl-1- (4-methylcyclohexyl) methanol and triethylamine are replaced with DBU, and according to Synthesis Example 4, 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di (1, 1-dimethyl-1- (4-methylcyclohexyl) methyl) ester was synthesized.
FABMS: m / z = 593

[Synthesis Example 7]
3- (Methylethoxysilyl) tetracyclo [4.4.0.1 ^2,5 . Synthesis example of 1 ^7,10 ] dodecane-8,9-dicarboxylic acid (1,1-dimethyl-1- (4-methylcyclohexyl) methyl) ester In synthesis example 4, 5-norbornene-2,3-dicarboxylic acid chloride Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8,9-dicarboxylic acid chloride, 1-methylcyclohexanol is replaced with 1,1-dimethyl-1- (4-methylcyclohexyl) methanol, triethylamine is replaced with DBU, and the rest is synthesized Synthesized according to Example 4, 3- (methylethoxysilyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane-8,9-dicarboxylic acid (1,1-dimethyl-1- (4-methylcyclohexyl) methyl) ester was obtained.
FABMS: m / z = 660

[Synthesis Example 8]
Synthesis Example of Siloxane Resin P-2 0.46 g of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester, 0.67 μL of trifluoroacetic acid was added with 3.85 μL of ethanol, The mixture was refluxed for 5 hours under a sealed stopper. The solvent of the reaction solution was distilled off under reduced pressure and then dried at 60 ° C. for 1 day to synthesize the target siloxane resin P-2. Tg: 80 ° C

[Synthesis Example 9]
Synthesis Example of Siloxane Resin P-9 In 0.46 g of 5- (methyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester, 0.31 g of TEOS, 0.67 μL of trifluoroacetic acid, and 3. 85 μL of ethanol was added and refluxed for 5 hours under a tight stopper. The solvent of the reaction solution was distilled off under reduced pressure and then dried at 60 ° C. for 1 day to synthesize the target siloxane resin P-2.
Tg: 100 ° C

[Synthesis Example 10]
Synthesis Example of Siloxane Resin P-10 2.49 g of 5- (phenyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester, 0.31 g of TEOS, 0.67 μL of trifluoroacetic acid. 85 μL of ethanol was added and refluxed for 5 hours under a tight stopper. The solvent of the reaction solution was distilled off under reduced pressure and then dried at 60 ° C. for 1 day to synthesize the target siloxane resin P-10.
Tg: 110 ° C.

  Siloxane resin P-11, siloxane resin P-12, siloxane resin P-18, and siloxane resin P-19 can be synthesized according to Synthesis Example 9 using the diester compounds synthesized in Synthesis Examples 1 to 7.

[Synthesis Example 11]
Synthesis Example of Siloxane Resin P-13 0.43 g of 5- (phenyldiethoxysilyl) norbornane-2,3-dicarboxylic acid di-t-butyl ester obtained in Synthesis Example 1, 0.31 g of TEOS, 0.35 g 3.85 μL of ethanol was added to 0.67 μL of trifluoroacetic acid of methyltriethoxysilane and refluxed for 5 hours under a sealed stopper. After the solvent of the reaction solution was distilled off under reduced pressure, it was dried at 60 ° C. for 1 day to synthesize the target siloxane resin P-13.
Tg: 105 ° C

  Siloxane resin P-14 to siloxane resin P-17 and siloxane resin P-20 can be synthesized according to Synthesis Example 11 using the diester compounds synthesized according to Synthesis Examples 1 to 7.

[Examples 1 to 12 and Comparative Example 1]
<Resist preparation>
(Formation of upper resist layer composition)
Each of the siloxane resins synthesized as shown above as Examples 1 to 12 shown in Table 1 was dissolved in a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) / cyclohexanone (8/2 mass ratio) and the solid content concentration was 7 mass%. Of the acid generator (PAG4-38: tri-t-butylphenylsulfonium nonaflate) in an amount of 5% by mass and the basic compound (2-phenylbenzimidazole) in the composition based on the solid content in the composition. 0.5% by mass based on the solid content and 0.01% by mass based on the solid content in the surfactant (Megafac F176 (manufactured by Dainippon Ink and Chemicals)) composition are obtained. The resulting solution was microfiltered with a 0.1 μm aperture membrane filter to obtain upper resist compositions 1-12.

(Formation of lower resist layer)
A 6-inch silicon wafer was coated with FHi-028DD resist (resist for i-line manufactured by FUJIFILM Electronics Materials Co., Ltd.) using a spin coater Mark8 manufactured by Tokyo Electron, and baked at 90 ° C. for 90 seconds to obtain a uniform film thickness of 0.55 μm. A membrane was obtained.
This was further heated at 200 ° C. for 3 minutes to obtain a lower resist layer having a thickness of 0.40 μm.

(Formation of upper resist layer)
On the first resist layer, an upper resist composition having a solid content concentration of 6% is applied in the same manner as the formation of the lower resist layer and heated at 130 ° C. for 90 seconds to form an upper resist having a thickness of 0.15 μm. A layer was obtained.

[Comparative Example 1]
The upper resist composition was prepared in the same manner as in Examples 1 to 12 except that the siloxane resin was replaced with a resin having the following structure (comparative resin) synthesized according to the method described in Synthesis Example 8 of JP-A-2002-278073. The lower layer resist and the upper layer resist were applied.

<Resist evaluation>
Each wafer thus obtained was exposed to an ArF excimer stepper manufactured by ASML with a resolving power mask while changing the exposure amount.
Then, after heating at 100 ° C. for 90 seconds in a clean room, the film was developed with a tetrahydroammonium hydroxide developer (2.38 mass%) for 60 seconds, rinsed with distilled water and dried to obtain a pattern (upper layer pattern). Further, the wafer having the upper layer pattern was etched (dry development) using a parallel plate type reactive ion etching apparatus DES-245R manufactured by Plasma System, and a pattern was formed on the lower layer. The etching gas was oxygen, the pressure was 20 mTorr, and the applied power was 100 mW / cm ² . The formed resist pattern was observed with a scanning electron microscope.

The sensitivity, resolution, and etching resistance were evaluated by the following methods.
(1) Sensitivity: Sensitivity is shown as an exposure amount for reproducing a mask pattern of 0.1 μm.
(2) Resolving power: The resolving power is indicated by the limiting resolving power at an exposure amount for reproducing a mask pattern of 0.1 μm.
(3) Etching resistance: Etching resistance was expressed as a relative ratio of etching rate to polyhydroxystyrene. A value of 1.0 or more and less than 1.2 was evaluated as good (◯), a value of 1.2 or more and less than 1.5 was allowed (Δ), and a value of 1.5 or more was determined as impossible (×).

  It was revealed that the photosensitive composition of the present invention exhibits high resolution performance with respect to an ArF excimer laser. Moreover, it became clear that it was excellent in sensitivity and etching resistance compared with the comparison resist.

Claims (9)

(A) a resin having a structural unit represented by the general formula (I) that increases the dissolution rate in an alkaline developer by the action of an acid, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation. The photosensitive composition characterized by the above-mentioned.

In general formula (I),
A represents a polycyclic hydrocarbon group. Q represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.
X ¹ and X ² each independently represent a group that decomposes and leaves by the action of an acid. The photosensitive composition according to claim 1, wherein the resin (A) further has a structural unit represented by the formula (II).

The photosensitive composition according to claim 1 or 2, wherein A in the general formula (I) is a polycyclic hydrocarbon group represented by the general formula (III).

In general formula (III):
m shows the integer of 0-3.
P ₁ represents a bond with a Si atom in formula (I).
P ₂ represents a bond with —COOX ₁ and —COOX ₂ in formula (I).   The photosensitive composition according to claim 3, wherein m in the general formula (III) is 0. 5. The photosensitive composition according to claim ¹ , wherein X ¹ and X ² in the general formula (I) are groups that are decomposed and eliminated by the action of an acid represented by the following general formula (IV). .

In general formula (IV), R < ¹ > -R < ³ > shows an alkyl group or a cycloalkyl group each independently. R ² and R ³ may combine to form a ring.   A pattern comprising a step of forming a second resist layer on the substrate provided with the first resist layer with the photosensitive composition according to claim 1, exposing and developing. Forming method. A compound represented by formula (V).

In general formula (V):
A represents a polycyclic hydrocarbon group.
Q represents an alkyl group, a cycloalkyl group, or an aryl group.
X ¹ and X ² each independently represents an organic group that is decomposed by the action of an acid to generate a group that dissolves in an alkaline developer.
R ⁴ and R ⁵ each independently represents an alkoxy group. The compound according to claim 7, wherein A in the general formula (V) is a polycyclic hydrocarbon group represented by the general formula (III).

In general formula (III), m shows the integer of 0-3.
P ₁ represents a bond with a Si atom in formula (I).
P ₂ represents a bond with —COOX ₁ and —COOX ₂ in formula (I). Resin (A) having general formula (V) as one of polymerization components.

In general formula (V):
A represents a polycyclic hydrocarbon group.
Q represents an alkyl group, a cycloalkyl group, or an aryl group.
X ¹ and X ^2, respectively independently, an organic group to produce a group that is soluble in an alkaline developing solution is decomposed by the action of an acid.
R ⁴ and R ⁵ each independently represents an alkoxy group.