JPH1195424A - Photosensitive composition and pattern forming method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive compsn. having high sensitivity to radia tion whose wavelength is in a specified range and radiation whose wavelength is below a specified value and also having high resolution by incorporating a specified compd., a compd. which generates an acid when irradiated with radiation whose wavelength is below a specified value and an alkali-soluble resin. SOLUTION: The photosensitive compsn. contains a compd. having at least one 1,2-naphthoquinonediazide-4- or-5-sulfonic ester group and at least one group convertible into an alkali-soluble group when decomposed by acid catalyzed reaction, a compd. which generates an acid when irradiated with radiation of <300 nm wavelength and an alkali-soluble resin. The photosensitive compsn. is a radiation sensitive compsn. having high sensitivity to radiation of 300-500 nm wavelength and radiation of <300 nm wavelength and also having high resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition applicable as a photoresist composition in a process for manufacturing a semiconductor device, and a pattern forming method using the same.

[0002]

2. Description of the Related Art Photoresists are used in the field of electronic components requiring various kinds of fine processing such as semiconductor integrated circuits such as LSIs. As an exposure apparatus used for forming a resist pattern, there is usually a reduced projection type mask aligner called a stepper. As a light source used in such an apparatus, the g-line of a mercury lamp (wavelength 43
6 nm), h-line (wavelength 405 nm), i-line (wavelength 365)
nm), KrF excimer laser (wavelength 248 n
m), ArF excimer laser (wavelength 193 nm),
Alternatively, an F ₂ excimer laser (wavelength: 157 nm) is often selected. In addition, since electron beams or ion beams can be processed more finely and can directly form a pattern, electron beam lithography or ion beam lithography has attracted attention as an important technology. Is being considered.

In recent years, as semiconductor integrated circuits such as LSIs have become more highly integrated, finer pattern formation has been required more than ever, and electron beam lithography technology or a photoresist material and process technology corresponding thereto have been required. Has become indispensable. However, the drawbacks are that the vacuum system is required for the electron beam lithography process, which takes a long time to transport the wafer, and that the electron beam scanning for pattern formation, that is, drawing, takes a long time, resulting in poor throughput. there were.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a photosensitive composition capable of improving throughput when applied to a photoresist for electron beam lithography, and a pattern forming method using the same. Is provided.

[0005]

[Means for Solving the Problems]

[Summary of the Invention] <Summary> The photosensitive composition of the present invention includes the following (1) to
(3). (1) a compound having at least one 1,2-naphthoquinonediazide 4- or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group; A compound which generates an acid when irradiated with radiation having a wavelength of less than 300 nm, which is different from 1), and (3) an alkali-soluble resin.

Further, the pattern forming method of the present invention comprises the following steps (a) to (e). (A) forming a photosensitive layer containing a photosensitive composition comprising the following (1) to (3) on a substrate:
(1) a compound having at least one 1,2-naphthoquinonediazide 4- or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group; A compound different from 1) that generates an acid when irradiated with actinic radiation having a wavelength of less than 300 nm, and (3) an alkali-soluble resin. (B) a wavelength of 3 in a predetermined area of the photosensitive layer;
Irradiating a radiation having a wavelength of less than 300 nm to a predetermined region of the photosensitive layer; (d) heat-treating the irradiated photosensitive layer; (E) developing the heat-treated photosensitive layer to selectively remove a predetermined region of the photosensitive layer from the substrate;

<Effect> According to the present invention, 300 to 500
Provided is a photosensitive composition having high sensitivity and high resolution to each of radiation having a wavelength of less than 300 nm and radiation having a wavelength of less than 300 nm, and a pattern forming method capable of producing fine patterns with high throughput.

[Specific description of the invention] <Photosensitive composition> The photosensitive composition of the present invention comprises (1)
A compound having at least one 2-naphthoquinonediazide-4 or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group (hereinafter referred to as an NQD compound), (2)
It is different from (1) and comprises a compound that generates an acid when irradiated with actinic radiation of less than 300 nm (hereinafter referred to as an acid releasing compound), and (3) an alkali-soluble resin.

(1) NQD compound The NQD compound used in the photosensitive composition of the present invention is 1,2
-A compound having at least one naphthoquinonediazide-4 or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group.

[0010] Such an NQD compound has a compound having two or more hydroxyl groups, preferably phenolic hydroxyl groups, as a skeleton compound, and at least one of the hydroxyl groups is 1,
It is substituted by a 2-naphthoquinonediazide-4 or 5-sulfonic acid ester group, and at least one of the other hydroxyl groups is substituted by a group which is decomposed by an acid-catalyzed reaction.

The photosensitive composition of the present invention has a composition of 300 to 500 n.
When the light of m is irradiated, the portion of the 1,2-naphthoquinonediazide-4 or 5-sulfonic acid ester group of the NQD compound absorbs radiation, is denatured, and becomes soluble in an alkaline aqueous solution. Further, the photosensitive composition of the present invention has a viscosity of 300 n.
When irradiated with radiation less than m, the acid-releasing compound (described in detail below) releases an acid, and the group that is decomposed into an alkali-soluble group by an acid-catalyzed reaction becomes alkali-soluble by the acid, and becomes soluble in an aqueous alkali solution. Become. For this reason, the photosensitive composition of the present invention has sensitivity to both radiation of 300 to 500 nm and radiation of less than 300 nm.

The skeleton compound of the NQD compound used in the photosensitive composition of the present invention may be any skeleton compound as long as the effects of the present invention are not impaired. In order to obtain a sufficient dissolution contrast, a lactone ring or a sultone ring is used. Are preferred. This is because a lactone ring or a sultone ring is cleaved in an aqueous alkali solution to generate a carboxyl group or a sulfonic acid group, so that the solubility in an aqueous alkali solution is improved. Such an NQD compound having a lactone ring or a sultone ring is represented by the following general formula (I).

Embedded image (Where OD is 1,2-naphthoquinonediazide-4
Or a 5-sulfonic acid ester group, OR ₁ is a group which is decomposed by an acid-catalyzed reaction and changes into an alkali-soluble group, and R ₂ , R ₃ and R ₃ are a hydrogen atom, a halogen atom, an alkyl group, an alkenyl A group selected from the group consisting of a group, an alkoxy group, an aryl group and an acyl group, wherein R ₂ and R ₃ may be the same or different, and a plurality of adjacent R ₂ , R ₃ or R ₄ may form a ring, X is CO or SO ₂ and m and n are
Each is an integer of 1 or more, and p, q and r are each an integer of 1 to 4. )

Typical of the compounds of general formula (I) are
m and n are each 1 or 2, p, q and r are each 0 or 1, and the OD group and the OR ₁ group are all present at the para position relative to the bonding position of the carbon atom of the cyclic ester.

The compounds constituting the basic skeleton of the compound of the general formula (I) are specifically phenolphthalein, cresolphthalein, thymolphthalein, naphtholphthalein, phenol red, phenolsulfophthalein, cresol purple, Cresol Red, and others. Accordingly, the compound of the general formula (I) used in the present invention is obtained by converting one of the hydrogens bonded to the phenolic hydroxyl group of the compound constituting the basic skeleton into a 1,2-naphthoquinone-4 or 5-sulfonic acid ester group. With
That is, it can be obtained by esterification with the sulfonic acid and replacing the hydrogen bonded to another phenolic hydroxyl group with a group that decomposes by an acid-catalyzed reaction.

Any group can be introduced into the NQD compound which decomposes by the acid-catalyzed reaction as long as the effect of the present invention is not impaired. (A) Substituents of t-butyl derivative, for example, t-butoxy Carbonyl group, t-butoxycarbonylmethyl group, t-butoxycarbonylethyl group,
And (b) linear or branched acetal groups such as 1-ethoxyethyl group, 1-propoxyethyl group, 1-n-butoxyethyl group, 1-iso-butoxyethyl group, 1-tert-butoxy group Ethyl group, and others, (c) cyclic acetal group, tetrahydrofuranyl group, tetrahydrapyranyl group, and others, (d)
Alkylsilyl groups, such as trimethylsilyl, triethylsilyl, triphenylsilyl, and others,
Can be mentioned as an example. These groups decomposed by the acid-catalyzed reaction can be introduced into the NQD compound in any combination of two or more kinds as necessary. Preferred specific examples of these NQD compounds are a compound in which one hydroxyl group of phenolphthalein is converted into 1,2-naphthoquinonediazide-5-sulfonic acid ester and the remaining one hydroxyl group is pyranylated, and one hydroxyl group of cresolphthalein is Was converted to 1,2-naphthoquinonediazide-5-sulfonic acid and the remaining one hydroxyl group was converted to t-butoxycarbonyl, and one hydroxyl group of thymolphthalein was converted to 1,2-naphthoquinonediazide-5-sulfonic acid. , A compound in which the remaining one hydroxyl group is t-butoxycarbonylated, and others.

The photosensitive composition of the present invention generally contains 5 to 50 parts by weight, preferably 10 to 40 parts by weight of the NQD compound based on 100 parts by weight of the alkali-soluble resin. When the content of the compound is out of this range, when a photosensitive layer using the photosensitive composition is exposed, the dissolution contrast between the exposed part and the unexposed part may be insufficient.

(2) Acid-releasing compound In the photosensitive composition of the present invention, an acid-releasing compound which is different from the NQD compound and which generates an acid upon irradiation with radiation having a wavelength of less than 300 nm, includes Any known in the art can be used.
Such compounds include onium salts, sulfonyl compounds, sulfonic acid ester compounds, organic halogen compounds, and others.

As the onium salt, for example, CF ₃ S
Examples thereof include O ₃ ⁻ , p-CH ₃ PhSO ₃ ⁻ , and diazonium salts, sulfonium salts, and iodonium salts each having a counter anion. Of these, triallylsulfonium salts and diallyliodonium salts are preferable. Specifically, diphenyliodonium, 4,4′-dibutylphenyliodonium, triphenylsulfonium, and other trifluoroacetates, trifluoromethanesulfonate, and diallyliodonium salts,
More specific examples thereof are diphenyliodonium trifluoromethanesulfonate, di (pt-butyl) phenyliodonium trifluoromethanesulfonate,
Triphenylsulfonium trifluoromethanesulfonate, and others. Such onium salts are
It is known as an acid generator having good sensitivity to radiation irradiation.

The sulfonyl compound has a wavelength of 300 n.
m, which release sulfonic acid upon irradiation with radiation of less than m.
And 348,838. Specific examples thereof are phenylsulfonylacetonitrile, bisphenylsulfonylmethane, triphenylsulfonylmethane, and others.

Examples of the sulfonic acid ester compound include nitrobenzyl p-toluenesulfonic acid and others.

The above-mentioned organic halogen compound which generates an acid upon irradiation with radiation having a wavelength of less than 300 nm is a compound which releases hydrogen halide upon irradiation with radiation. 3rd, 51st
No. 5,552 and 3,536,489, and the like. Specific examples thereof are 2,4,6-trichloromethyltriazine, and others.

The photosensitive composition of the present invention contains the acid-releasing compound in an amount of generally 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on the total weight of the solid content of the photosensitive composition.
contains. If the content of the acid-releasing compound is less than this, the sensitizing effect due to the compounding of the acid-releasing compound may be insufficient.If the content of the acid-releasing compound is greater than this, the photosensitive composition may be used. The wavelength of the resist is 300 to 5
When exposed to radiation of 00 nm, the dissolution contrast may be insufficient.

(3) Alkali-soluble resin The photosensitive composition of the present invention comprises an alkali-soluble resin. Such resins include those having a phenol skeleton known in the art, such as phenol novolak resin, xylenol novolak resin, vinyl phenol resin, cresol novolak resin, copolymer of vinyl phenol and acrylic resin, and others. Can be used. Although the molecular weight and the like of these resins are not particularly limited, generally, the weight average molecular weight is 1,000 to 3
A polymer of 000 is used. These resins may be used as a mixture of two or more of them as necessary.

(4) Other Components The photosensitive composition of the present invention contains, if necessary, a resin or an organic compound in which part or all of an alkali-soluble group is protected by a group capable of decomposing by an acid-catalyzed reaction. Can be. This component is different from the alkali-soluble component (3) in that the alkali-soluble group is protected and is hardly soluble or insoluble in an aqueous alkali solution.

As an example of such a resin or compound, part of the hydroxyl groups of the polyhydroxystyrene resin is t-
A resin protected with a butoxycarbonyl group, a t-butoxycarbonylmethyl group, a tetrahydropyranyl group, or a 1-ethoxyethyl group, wherein one or two of the hydroxyl groups of bisphenol A are a t-butoxycarbonyl group, or a t-butoxycarbonyl group;
A compound protected with a butoxycarbonylmethyl group, wherein one or two of the hydroxyl groups of phenolphthalein are a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group,
Or a compound protected by a tetrahydropyranyl group, a compound in which one or two of the hydroxyl groups of cresolphthalein is protected by a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, or a tetrahydropyranyl group; One or two of the hydroxyl groups are t
-Butoxycarbonyl group, t-butoxycarbonylmethyl group, or a compound protected with a tetrahydropyranyl group, and others.

When such a resin or compound is contained in the composition of the present invention, the content is generally 20 parts by weight or less based on the total weight of the alkali-soluble resin contained in the photosensitive composition of the present invention. is there. If the content exceeds 20 parts by weight, the photosensitive layer using the composition of the present invention has a wavelength of 300 to
Dissolution contrast when irradiated with 500 nm radiation may be insufficient.

[0027] The photosensitive composition of the present invention can also contain, if necessary, various additives commonly used in photoresists. Such additives include surfactants (coating modifiers), environmental stabilizers (eg, amine compounds, pyridine compounds, and others), and others.

(5) Solvent The photosensitive composition of the present invention is generally prepared by dissolving the above-mentioned components in an organic solvent and, if necessary, filtering. As such a solvent, any solvent can be used as long as it does not impair the effects of the present invention.Specifically, cyclohexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate, Butyl cellosolve acetate, methoxymethyl propionic acid, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl acetate, butyl acetate, isoamyl acetate, γ-butyrolactone, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, and others. Can be These organic solvents can be used as a mixture of two or more as necessary.

<Pattern Forming Method> The pattern forming method of the present invention uses the above photosensitive composition. The method will be described below.

First, the above-mentioned photosensitive composition dissolved or diluted with the above-mentioned organic solvent, if necessary, is applied on a substrate. The substrate to be used is arbitrary, but for example, a silicon wafer (which may have various insulating films, electrodes, or wirings on its surface), a compound semiconductor wafer (for example, GaAs, AlGaAs, and others) Wafers), various masks (for example, chrome mask,
SiN mask, MoSi mask, and others).

The method of applying the photosensitive composition onto the substrate is also optional, and specific examples include spin coating, dip coating, flow coating, curtain coating, and other methods.

The photosensitive composition applied on the substrate is generally dried at a temperature of 200 ° C. or lower, preferably 70 to 150 ° C., to form a resist film (photosensitive layer).

Next, the photosensitive layer is exposed. Exposure is performed by exposure to radiation having a wavelength of 300 to 500 nm and exposure to radiation having a wavelength of 3 to 500 nm.
At least twice with exposure to radiation of less than 00 nm. In exposure with radiation having a wavelength of 300 to 500 nm, a fine pattern that is used to expose a relatively coarse pattern and is difficult to form by such exposure is used.
Exposure is performed with radiation having a wavelength of less than 300 nm. By exposing with such two kinds of light, the wavelength becomes 300 to
Fine patterns that are difficult to create by irradiating radiation of 500 nm can be created with much higher throughput than when irradiating radiation having a wavelength of less than 300 nm.

Any radiation source having a wavelength of 300 to 500 nm can be used. Specific examples include mercury lamps, incandescent lamps, xenon discharge tubes, hydrogen discharge tubes, and others. Among these, the mercury lamp i
Preferably, a line or g line is used.

Any radiation having a wavelength of less than 300 nm can be used. Specifically, KrF or A
Excimer lasers such as rF, X-rays, electron beams, and others.

The exposed light-sensitive layer can be subsequently processed by any method, for example, hot plate, heating furnace, infrared irradiation, and others.
Heat treatment, that is, baking. At this time,
The heating temperature is generally not higher than 200 ° C. Subsequently, a developing process is performed with a developing solution. As the developing solution, those commonly used in the art, for example, an organic alkali aqueous solution such as tetramethylammonium hydroxide or an inorganic alkali aqueous solution such as potassium hydroxide or sodium hydroxide are used. These alkaline aqueous solutions
Usually, it is used at a concentration of 15% by weight or less. This developing solution is supplied to the exposed / heat-treated resist film by a dipping method, a spray method, a paddle method, or the like, and developed.
The developed photosensitive layer is optionally rinsed with water or the like.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Synthesis Example 1 16 g (0.05 mol) of phenolphthalein and 13.3 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride were mixed with 200 g of tetrahydrofuran to form a solution. 10 g of triethylamine is added to this solution.
(0.1 mol) was slowly dropped with a dropping funnel. After the completion of the dropping, the mixture was reacted at 25 ° C. for 3 hours, and the obtained mixture was poured into a large amount of 1% hydrochloric acid to precipitate a reaction product.
The precipitate was filtered, washed and dried to obtain a mixture of mono-substituted and di-substituted phenolphthalein with 1,2-naphthoquinonediazide-5-sulfonic acid ester group. Next, the obtained mixture was dissolved in dioxane, and the monosubstituted product was separated by a silica gel column. The obtained monosubstituted product was dissolved in dihydropyran, a few drops of concentrated hydrochloric acid were added, and the mixture was stirred and reacted at room temperature for 2 days. After the dry-up, the plate is thoroughly washed with water, phenolphthalein is used as a skeletal compound, one phenolic hydroxyl group is esterified with 1,2-naphthoquinonediazide-5-sulfonic acid, and another phenolic hydroxyl group is tetrahydropyran. (Hereinafter referred to as Compound A).

Synthesis Example 2 In the same manner as in Synthesis Example 1, a monosubstituted 1,2-naphthoquinone-5-sulfonic acid ester having cresolphthalein as a skeleton compound was obtained. This compound was dissolved in tetrahydrofuran to form a solution, and di-t-butyl carbonate, 18-crown ether-6, and potassium carbonate were mixed with the solution, and the mixture was stirred and reacted at 30 ° C. for 2 days. After the reaction mixture was dried up, it was washed with a 1% oxalic acid aqueous solution, and further thoroughly washed with water to make cresolphthalein a skeletal compound, and one phenolic hydroxyl group was treated with 1,2-naphthoquinonediazide-5-sulfonic acid. Esterified and another phenolic hydroxyl group is t
A compound protected with -butoxycarbonyl was obtained (hereinafter, referred to as compound B).

Synthesis Example 3 In the same manner as in Synthesis Example 1, a monosubstituted 1,2-naphthoquinone-5-sulfonic acid ester having thymolphthalein as a skeleton compound was obtained. This compound is dissolved in tetrahydrofuran to form a solution, and bromoacetic acid-t is added to the solution.
-Butyl carbonate and triethylamine were mixed and reacted by stirring at 35 ° C. for 2 days. After the reaction mixture was dried up, it was washed with water and dried to obtain thymolphthalein as a skeletal compound, one phenolic hydroxyl group was esterified with 1,2-naphthoquinonediazide-5-sulfonic acid, and another phenolic hydroxyl group. Is t
A compound protected with -butoxycarbonyl was obtained (hereinafter referred to as compound C).

SYNTHETIC EXAMPLE 4 The cresolphthalein was substituted for 1,2-naphthoquinonediazide-5-sulfonyl chloride by 1,2-naphthoquinonediazide-4-sulfonyl chloride in the same manner as in Synthetic Example 2 except that As a compound, a compound in which one phenolic hydroxyl group was esterified with 1,2-naphthoquinonediazide-4-sulfonic acid and another phenolic hydroxyl group was protected with t-butoxycarbonyl was obtained (hereinafter, referred to as compound D). Call).

Examples 1 to 6 and Comparative Examples 1 to 2 were applied with a resist composition solution having the composition shown in the table to a silicon wafer by spin coating.
After drying at a temperature of 2 ° C. for 2 minutes, a resist film having a thickness of 0.5 μm was formed.

After imagewise exposing each resist film with i-line,
It was baked at 00 ° C. for 3 minutes and then developed with a 2.38% aqueous solution of tetramethylammonium hydroxide to form a resist pattern, and its sensitivity and pattern shape were evaluated. The same evaluation was performed using an electron beam (50 KeV) as a light source. The results obtained were as shown in the table.

[0043]

[Table 1]

[0044]

The photosensitive composition of the present invention has a content of 300 to 50.
The high sensitivity and the high resolution to each of the radiation of 0 nm and the radiation having a wavelength of less than 300 nm, and the fact that a fine pattern can be produced with high throughput by the pattern forming method of the present invention are described in the Summary of the Invention. Is as described above.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 502R

Claims (6)

[Claims] 1. A photosensitive composition comprising the following (1) to (3). (1) a compound having at least one 1,2-naphthoquinonediazide 4- or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group; A compound which generates an acid when irradiated with radiation having a wavelength of less than 300 nm, which is different from 1), and (3) an alkali-soluble resin. 2. The photosensitive composition according to claim 1, wherein the compound (1) has a lactone ring or a sultone ring. 3. The photosensitive composition according to claim 2, wherein the compound (1) has the following general formula (I). Embedded image (Where OD is 1,2-naphthoquinonediazide 4-
Or a 5-sulfonic acid ester group, OR ₁ is a group which is decomposed by an acid-catalyzed reaction and changes into an alkali-soluble group, and R ₂ , R ₃ and R ₃ are a hydrogen atom, a halogen atom, an alkyl group, an alkenyl A group selected from the group consisting of a group, an alkoxy group, an aryl group and an acyl group, wherein R ₂ and R ₃ may be the same or different, and a plurality of adjacent R ₂ , R ₃ or R ₄ may form a ring, X is CO or SO ₂ and m and n are
Each is an integer of 1 or more, and p, q and r are each an integer of 1 to 4. ) 4. The photosensitive composition according to claim 1, wherein the compound (2) is an onium salt or a sulfonyl compound. 5. The photosensitive composition according to claim 1, which comprises a resin or an organic compound in which a part or all of an alkali-soluble group is protected by a group capable of decomposing by an acid catalyzed reaction. 6. A pattern forming method comprising the following steps (a) to (e). (A) forming a photosensitive layer containing a photosensitive composition comprising the following (1) to (3) on a substrate:
(1) a compound having at least one 1,2-naphthoquinonediazide 4- or 5-sulfonic acid ester group and at least one group that is decomposed by an acid-catalyzed reaction to change into an alkali-soluble group; A compound different from 1) that generates an acid when irradiated with actinic radiation having a wavelength of less than 300 nm, and (3) an alkali-soluble resin. (B) a wavelength of 3 in a predetermined area of the photosensitive layer;
Irradiating a radiation having a wavelength of less than 300 nm to a predetermined region of the photosensitive layer; (d) heat-treating the irradiated photosensitive layer; (E) developing the heat-treated photosensitive layer to selectively remove a predetermined region of the photosensitive layer from the substrate;