JPH10133375A - Chemical amplifying positive resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high sensitivity and high resolution of a resist and to increase adhesion property to a substrate and stability with time during storage after exposure by using a resin having 1-ethoxyethyl group and combining with an acid producing agent having a specified structure. SOLUTION: This chemically amplifying positive resist compsn. contains a resin (A) and an acid producing agent (B). The resin (A) has polymn. units derived from an ester compd. having ethylene type unsatd. bonds, and at least a part of the ester is 1-ethoxyethylester. The acid producing agent (B) is selected from compds. expressed by formulae I-IV. In formula I-IV, R represents alkyl groups, alicyclic hydrocarbon residues, aryl groups, aralkyl groups or camphor groups and may have alkoxy, halogen or nitro substituents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemically amplified positive resist composition used for fine processing of semiconductors.

[0002]

2. Description of the Related Art A lithography process using a resist composition is usually employed for fine processing of a semiconductor.
In lithography, the shorter the exposure wavelength, the higher the resolution in principle, as expressed by the Rayleigh diffraction limit equation. Exposure light sources for lithography used in the manufacture of semiconductors have become shorter each year, such as g-line with a wavelength of 436 nm, i-line with a wavelength of 365 nm, and a KrF excimer laser with a wavelength of 248 nm. ArF excimer laser is promising.

Since the life of a lens used in an ArF excimer laser exposure machine is shorter than that of a lens for a conventional exposure light source, the exposure time to an ArF excimer laser beam is preferably as short as possible. For this purpose, since it is necessary to increase the sensitivity of the resist, a so-called chemically amplified resist utilizing a catalytic action of an acid generated by exposure is used. Among the chemically amplified resists, particularly the positive resist is remarkable, but there is a problem of a temporal change (so-called time delay effect) after the exposure, which is caused by the deactivation of an acid due to an amine in the air. .

On the other hand, the resin used for the resist for ArF excimer laser exposure does not have an aromatic ring in order to secure the transmittance of the resist, and it has an alicyclic ring instead of an aromatic ring in order to have dry etching resistance. It is known that those having However, when such a resin is used, there is a problem that development peeling is likely to occur due to insufficient adhesiveness during development, particularly when the hydrophilicity of the resin is insufficient.

Iwasa et al., Proceedings of the 43rd Symposium on Applied Physics, Spring 1996, 27a-ZW-1, and Nakano et al., Second
International Symposium on 193 nm Lithography Dig
In estof Abstracts, pp. 34-35 (1996), a high-sensitivity resist is obtained by using a resin having an alicyclic group and having a 1-ethoxyethyl group as a group capable of leaving by the action of an acid. It is shown that it can be obtained. A resin having a 1-ethoxyethyl group has a feature of high sensitivity because of low activation energy for cleavage by an acid.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to
Contains a resin having an ethoxyethyl group and an acid generator,
A chemically amplified positive resist composition suitable for excimer laser lithography such as ArF and KrF. It has high sensitivity and high resolution, has excellent adhesion to substrates, and has good stability over time after exposure. It is to provide something excellent.

The inventors of the present invention have obtained high sensitivity and high resolution in a chemically amplified positive resist composition using a resin having a 1-ethoxyethyl group by combining it with an acid generator having a certain structure. In addition, the present inventors have found that the adhesiveness to the substrate and the stability with time of exposure after exposure are improved, and the present invention has been completed.

[0008]

That is, the present invention provides a chemically amplified positive resist composition containing the following resin (A) and acid generator (B).

(A) a resin having a polymerized unit derived from an ester compound having an ethylenically unsaturated bond, wherein at least a part of the ester is 1-ethoxyethyl ester;

(B) The following formula (I), (II), (III) or (IV)

[0011]

(Wherein R represents an alkyl group optionally substituted by alkoxy, halogen or nitro, an alicyclic hydrocarbon residue, an aryl group, an aralkyl group or a camphor group) The acid generator of choice.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The resin (A) used in the present invention has a polymerized unit derived from an ester compound having an ethylenically unsaturated bond, and at least a part of the ester is 1-ethoxyethyl ester. is there. This resin usually has no aromatic ring and preferably has an alicyclic ring. Here, the alicyclic ring is particularly an alicyclic hydrocarbon group,
It is also preferably a bridged hydrocarbon ring, and examples thereof include a bornane ring, a norbornane ring, a tricyclodecane ring, a tetracyclododecane ring, and an adamantane ring. More specific resins include those having a polymerized unit derived from an alicyclic ester of (meth) acrylic acid and those having a structural unit derived from a vinyl ester or isopropenyl ester of an alicyclic carboxylic acid. be able to. A typical resin is, for example, the following formula (V)
Or it has a structure shown by (VI).

[0014]

Wherein R ¹ , R ² and R ³ independently represent hydrogen or methyl; X represents a monovalent alicyclic hydrocarbon group; and Y represents a divalent alicyclic hydrocarbon group. the expressed; Z is -C (= O) O- and represented, wherein which of the bonds in Z - (CH ₂₎ may be attached to the n-Y-; n represents 0 or 1; a, b and c are the molar amounts of each repeating unit, and when a + b + c is 100, a is 20 to 60;
b represents a number of 20 to 60, c represents a number of 0 to 40; d and e are also the molar amount of each repeating unit;
Where d represents a number from 20 to 60 and e represents a number from 80 to 40.

In the formula (V), the alicyclic hydrocarbon group represented by X can have, for example, about 6 to 18 carbon atoms. Specifically, isobornyl derived from bornane,
Examples include norbornyl derived from norbornane, tricyclodecyl derived from tricyclodecane, tetracyclododecyl derived from tetracyclododecane, and adamantyl derived from adamantane. In the formula (VI), the divalent alicyclic hydrocarbon group represented by Y can also have, for example, about 6 to 18 carbon atoms. (Both of the two bonds are emitted from ring carbon atoms), norbornane divalent group, tricyclodecane divalent group, tetracyclododecane divalent group, adamantane divalent group, and the like. These alicyclic hydrocarbon groups can also lead to an ester bond represented by Z via methylene as shown in the above formula (VI). Z in the formula (VI) may have any bond of —C (＝ O) O— bonded to methylene or Y of — (CH ₂ ) n —Y—. Thus, this moiety can be a structure derived from a (meth) acrylic acid ester or a structure derived from a vinyl or isopropenyl ester of an alicyclic carboxylic acid.

In the above formula (V), a representing the amount of the alicyclic ester unit of (meth) acrylic acid can be a number in the range of 20 to 60, preferably a number in the range of 20 to 50. It is. In addition, b representing the amount of 1-ethoxyethyl ester unit of (meth) acrylic acid can be a number in the range of 20 to 60, and is preferably a number in the range of 30 to 60. In the formula (V), c representing the amount of the (meth) acrylic acid unit may be zero as is clear from the definition, and the case where the (meth) acrylic acid unit is not included is included, but usually, It is preferable that this (meth) acrylic acid unit also exists to some extent, and therefore, n is preferably a number in the range of about 5 to 40.

On the other hand, one of the alicyclic carboxylic acids in the formula (VI)
D, representing the amount of structural units having -ethoxyethyl ester, can be a number in the range of 20-60, preferably a number in the range of 20-50. E representing the amount of the structural unit having an alicyclic carboxylic acid group is a number of 100-d.

The resin having the structure of the formula (V) is (meth)
Alicyclic ester of acrylic acid, (meth) acrylic acid 1
It can be produced by using ethoxyethyl ester and optionally (meth) acrylic acid and copolymerizing them. The resin having the structure of the formula (VI) has 1
A vinyl or isopropenyl ester of an alicyclic carboxylic acid having an ethoxyethyl group or an alicyclic ester of (meth) acrylic acid and a vinyl or isopropenyl ester of an alicyclic carboxylic acid having a free carboxyl group or ( It can be produced by copolymerizing these two components with an alicyclic ester of (meth) acrylic acid. As the resin having the structure of the formula (VI), typically, for example, a copolymer of 1-ethoxyethoxycarbonyltricyclodecylmethyl (meth) acrylate and (meth) acryloyloxymethyltricyclodecanecarboxylic acid or And a copolymer of vinyl 1-ethoxyethoxycarbonyltricyclodecanecarboxylate and vinyloxycarbonyltricyclodecanecarboxylate.

In the present invention, the resin (A) consisting of an ester-based vinyl polymer having a 1-ethoxyethyl group as a protecting group which is released by the action of an acid as described above is used, and an acid is generated by exposure to light. The compound represented by the formula (I), (II), (III) or (IV) is used as an acid generator acting on a protecting group in the resin (A). Among these acid generators, compounds represented by formula (I), (II) or (III) are particularly preferred. In formulas (I) to (IV),
R is a residue of a sulfonic acid, that is, a group obtained by removing a sulfonic acid group from a sulfonic acid, and is an alkyl group, an alicyclic hydrocarbon residue, an aryl group, an aralkyl group or a camphor group.

The alkyl group represented by R may have, for example, about 1 to 10 carbon atoms and may be unsubstituted or substituted. If it has 3 or more carbon atoms, it may be linear or molecular. May be. Examples of the alkyl substituent include alkoxy (preferably having about 1 to 4 carbon atoms), halogen such as fluorine, chlorine and bromine, and nitro. Alicyclic hydrocarbon residues are those derived from hydrocarbons containing alicyclic rings.
It is a valent group, and may be a monocyclic or bridged polycyclic ring. In particular,
Monocyclic ones such as cyclohexyl and cyclohexylmethyl, and polycyclic ones such as adamantyl (that is, a monovalent group derived from adamantane, particularly 1-adamantyl) are exemplified. The aryl group can be, for example, phenyl or naphthyl, and these phenyl and naphthyl may be unsubstituted or substituted. Examples of the substituent of phenyl or naphthyl include alkyl (preferably having about 1 to 4 carbon atoms) and alkoxy (preferably having 1 to 4 carbon atoms).
Degree), halogens such as fluorine, chlorine and bromine, and nitro. The aralkyl group can be, for example, benzyl or phenethyl, and the aromatic ring constituting these aralkyl groups may also have a substituent such as alkyl, alkoxy, halogen and nitro. The camphor group means a monovalent group derived from camphor, and is particularly preferably a 10-camphor group, that is, a group obtained by removing a sulfonic acid group from, for example, 10-camphorsulfonic acid.

In general, in a chemically amplified positive resist composition, a basic compound, particularly a basic nitrogen-containing organic compound, for example, an amine is added as a quencher, thereby causing a post-exposure delay. It is known that performance degradation due to deactivation of an acid can be improved. In the present invention, it is preferable to add such a basic compound. Specific examples of the basic compound used for the quencher include those represented by the following formulas.

[0023]

Wherein R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵
Represents, independently of each other, hydrogen, alkyl, cycloalkyl, aryl or alkoxy optionally substituted by a hydroxyl group, and A represents alkylene, carbonyl or imino. Here, alkyl and alkoxy represented by R ^{11 to} R ¹⁵ can have about 1 to 6 carbon atoms, cycloalkyl can have about 5 to 10 carbon atoms,
And aryl can have about 6 to 10 carbon atoms. The alkylene represented by A has 1 to 6 carbon atoms.
And may be linear or branched.

The resist composition of the present invention contains 80 to 99.9% by weight of the resin (A) and 0.1 to 20% by weight of the acid generator based on the weight of the total solid content. Is preferred. When a basic compound is used as a quencher, it is preferably contained in the range of 0.001 to 0.1% by weight based on the total solid content of the resist composition. The composition may also contain, if necessary, sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, dyes, etc.
Various additives may be contained in small amounts.

The resist composition of the present invention usually becomes a resist solution in a state where each of the above components is dissolved in a solvent, and is applied onto a substrate such as a silicon wafer. The solvent used here may be any one that dissolves each component, has an appropriate drying speed, and provides a uniform and smooth coating film after the solvent evaporates. There can be. For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate, acetone,
Examples include ketones such as methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents can be used alone or in combination of two or more.

The resist film applied on the substrate and dried is subjected to an exposure treatment for patterning, and then to a heat treatment for accelerating a deprotection group reaction.
Developed with an alkaline developer. The alkaline developer used here can be various alkaline aqueous solutions used in this field, but generally, an aqueous solution of tetramethylammonium hydroxide is often used.

[0028]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Parts and percentages in the examples are by weight unless otherwise specified. First, synthetic examples of the resins used in the examples and comparative examples will be described.

Synthesis of Resin A1 22.2 g (0.2 mol) of isobornyl methacrylate, 15.8 g (0.2 mol) of 1-ethoxyethyl methacrylate, 8.6 g (0.2 mol) of methacrylic acid and methyl isobutyl 95 g of ketone was charged into a 500 ml round bottom flask, and 1.98 g (0.0) of azobisisobutyronitrile was used as an initiator.
12 mol) was added. Thereafter, the temperature was raised to 95 ° C., and the mixture was heated for 8 hours. After completion of the heating, the mixture was cooled to room temperature, poured into a large amount of heptane to precipitate twice, and purified. As a result, a resin A1 having a repeating unit represented by the following formula in a molar ratio of 1/3 each and a weight average molecular weight of about 10,000 was obtained.

[0030]

Synthesis of Resin AX (Comparative) The above resin A1 except that tert-butyl methacrylate was used in an equimolar amount instead of 1-ethoxyethyl methacrylate.
In the same manner as in the synthesis of the above, each of the repeating units represented by the following formula has a molar ratio of 1/3, and a weight average molecular weight of about 10,
000 resin AX was obtained.

[0032]

The acid generators and quenchers used in the following Examples and Comparative Examples are as follows, and are indicated by the respective symbols.

(B) Acid generator B1: diphenyldisulfone (manufactured by Midori Kagaku Co., Ltd.) B2: benzoin tosylate (manufactured by Midori Kagaku Co., Ltd.) B3: α-methylol benzoin tosylate (manufactured by Midori Kagaku Co., Ltd.) B4: α-methylolbenzoin p-tert-butylbenzenesulfonate B5: bis (2,4-dimethylphenylsulfonyl) diazomethane (DAM-105, manufactured by Midori Kagaku Co., Ltd.) BX: triphenylsulfonium trifluoromethylsulfonate (Midori Chemical (TPS-105)

(C) Quencher C1: 4,4'-methylenebis (2-ethyl-6-methylaniline) (Kayahard AA, manufactured by Nippon Kayaku Co., Ltd.) C2: 2,6-diisopropylaniline C3: N- Phenyldiethanolamine

The structure of each compound is as follows.

[0037]

Examples 1 to 7 and Comparative Examples 1 to 3 In each case, 15 parts of the resin shown in Table 1 and 0.15 of the acid generator were used.
Parts and a quencher were dissolved in 60 parts of propylene glycol monomethyl ether acetate, and filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist solution. This was applied to a silicon wafer treated with hexamethyldisilazane (HMDS) or a silicon wafer coated with an organic antireflection film so that the film thickness after drying was 0.72 μm. The organic anti-reflection film was applied with "XHRi-11" manufactured by Brewer Co. under a baking condition of 175 ° C. and 60 seconds to a thickness of 1,700 °. Prebaking after the application of the resist solution was performed on a direct hot plate at 90 ° C. for 60 seconds. A KrF excimer stepper [“NSR 1755 EX8A” manufactured by Nikon Corporation, NA
= 0.45] to expose the line and space pattern.

Immediately after the exposure, or after leaving for 5 minutes in a clean room having an ammonia concentration of 3 ppb after the exposure, post-exposure bake (PEB) was performed on a hot plate at 100 ° C. for 60 seconds. Dip development was performed for 60 seconds with a developer obtained by diluting a 2.38% aqueous solution of tetramethylammonium hydroxide with pure water to 1/20. The pattern after the development was observed with a scanning electron microscope, and the sensitivity, resolution, and change with time of the pattern obtained from the resist film provided on the organic antireflection film substrate were examined by the following methods.

Sensitivity: A 0.5 μm line-and-space pattern was obtained for the sample subjected to PEB immediately after the exposure:
The exposure amount (effective sensitivity) was 1.

Resolution: The sample subjected to PEB immediately after exposure was represented by the minimum size of a line-and-space pattern separated by the exposure amount of the effective sensitivity.

Time-dependent change: The image was displayed at the resolution of a sample which was left for 5 minutes after exposure.

The pattern on the substrate on which the organic anti-reflection film was not provided was evaluated for adhesiveness, and the pattern adhered to the substrate at a light exposure of 0.5: 1 line-and-space pattern was 1: 1. 、, those that were peeled were indicated by x. Table 1 shows the above results together with the composition of the resist.

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example No. Resin Acid generator Quencher Effective sensitivity Resolution Change over time Adhesion ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 A1 B1 C1 15 mJ / cm ² 0.30μm 0.35μm ○ 〃 2 A1 B2 C1 20 mJ / cm ² 0.32μm 0.35μm ○ ３ 3 A1 B3 C1 25 mJ / cm ² 0.30μm 0.35μm ○ 〃 4 A1 B4 C2 20 mJ / cm ² 0.28μm 0.33 [mu] m ○ 〃 5 A1 B5 C1 60 mJ / cm 2 0.30μm 0.35μm ○ 〃 6 A1 B3 C2 20 mJ / cm 2 0.28μm 0.35μm ○ 〃 7 A1 B2 C3 25 mJ / cm 2 0.27μm 0.35μm ○ ───比較 Comparative Example 1 A1 BX C1 20 mJ / cm ² 0.30μm 0.50μm ○ Answer No image 〃 2 AX BX C1 300 mJ / cm ² 0.50 μm 0.50 μm × No resolution 〃 3 AX B2 C1> 1,000 − − × mJ / cm ² ━━━━━━━━━━━━━━ ━━ ━━━━━━━━━━━━━━━━━━━━

The compositions used in Examples 1 to 7 similarly give a resist pattern having excellent performance even when exposed with an ArF excimer laser exposure machine.

[0046]

EFFECTS OF THE INVENTION The chemically amplified positive resist composition of the present invention is excellent in sensitivity and resolution, has good adhesiveness to a substrate, is hardly affected by the withdrawal time after exposure, and has stability over time. Is excellent.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuki Takemoto 3-1-198 Kasuganaka, Konohana-ku, Osaka Sumitomo Chemical Co., Ltd.

Claims (4)

[Claims] 1. A resin having (A) a polymerization unit derived from an ester compound having an ethylenically unsaturated bond, wherein at least a part of the ester is 1-ethoxyethyl ester, and (B) a resin represented by the following formula: (I), (II), (III) or (IV) Wherein R represents an alkyl group optionally substituted with alkoxy, halogen or nitro, an alicyclic hydrocarbon residue, an aryl group, an aralkyl group or a camphor group. A chemically amplified positive resist composition comprising a generator. 2. The composition according to claim 1, wherein the resin (A) has an alicyclic ring and no aromatic ring. 3. The resin (A) having the following formula (V) or (VI) (Wherein R ¹ , R ² and R ³ independently represent hydrogen or methyl; X represents a monovalent alicyclic hydrocarbon group; Y represents a divalent alicyclic hydrocarbon group) Z is -C (=
O) O-, wherein any bond in Z is-(CH
₂ ) may be bonded to nY-; n represents 0 or 1;
a, b and c are the molar amounts of each repeating unit, and a
Assuming that + b + c is 100, a is 20 to 60 and b is 2
0 to 60 and c each represent a number of 0 to 40; d and e are also molar amounts of each repeating unit, and when d + e is 100, d is 20 to 60 and e is a number of 80 to 40. Represents)
The composition according to claim 2, which has a structure represented by the following formula: 4. The method according to claim 1, further comprising a basic compound.
A composition according to any one of claims 1 to 3.