JPH10282667A - Pattern forming material and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material which is made transparent in a far UV region and has high resistance against dry etching and solubility in water-based alkali by incorporating a resin soluble in a water-based alkali, an acid-producing compd. and a compd. having reactivity to decrease solubility of a coating film in an alkaline soln. by acid catalyst reaction. SOLUTION: The pattern forming mateal contains an alkali-soluble resin containing carboxylic acid in side chains, a compd. which produces acid by irradiation of active chemical rays, and a compd. having reactivity which decreases solubility in an alkaline soln. by acid catalyst reaction. As for the compd. which produces acid by active chemical rays, various kinds of diazonium salts, onium salts, esters of alkyl sulfonic acid and compds. containing plural phenol-type hydroxyl groups, and various halogen compds, can be used. The compd. having reactivity which decreases soubility in an alkaline soln. by acid catalyst reaction is preferably a deriv. of aliphatic hydrocarbon compd. having at least one alcohol-type hydroxyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pattern forming material and a pattern forming method used in a lithography process used for manufacturing a semiconductor device and the like, and a method for manufacturing a semiconductor device and the like including the lithography process.

[0002]

2. Description of the Related Art A photolithography technique for forming a fine pattern on the order of microns or submicrons in an electronic device such as a semiconductor has played a central role in mass production fine processing technology. The recent demand for higher integration and higher density of semiconductor devices is
Many advances have been made in microfabrication technology. In particular, as the minimum processing size approaches the exposure wavelength, photolithography technology using a KrF excimer laser (248 nm) from a g-line (436 nm) and i-line (365 nm) of a high-pressure mercury lamp and a shorter wavelength light source is developed. It has been. In response to these changes in the exposure wavelength, materials corresponding to the respective wavelengths of the photoresist have been developed.

Conventionally, photoresists suitable for these wavelengths have different photosensitizers or photosensitive mechanisms. However, aqueous alkali development utilizing the aqueous alkali solubility of a resin or a polymer material having a phenolic hydroxyl group is industrially required. Has been used for These resins or polymer materials inevitably contain a large amount of aromatic rings, which was also a chemical structural element for improving the etching resistance in a dry etching step after the formation of a resist pattern.

In recent years, expectations have been growing for photolithography using an ArF excimer laser (193 nm) as a light source as a photolithography for a region having a minimum processing dimension smaller than 0.25 μm. However, this wavelength is the absorption maximum due to the aromatic ring, and in the case of a photoresist material which has been conventionally industrially used and has an aromatic ring structure as a main component, an exposure latent image can be formed only on the extreme surface of the photoresist film. However, it has been difficult to form a fine resist pattern by aqueous alkali development.

[0005] Polymethyl methacrylate (PMMA) or the like is known as a polymer material for resist having a high transmittance at a wavelength of 193 nm of an ArF excimer laser. Further, the dry etching resistance and the resist sensitivity are far from practical use.

On the other hand, various resist materials having high transmittance in this wavelength region and high dry etching resistance have been proposed. ArF excimer laser wavelength 19
As a chemical structure that is transparent in the far ultraviolet region including 3 nm and can impart dry etching resistance to a resist material in place of an aromatic ring, use of an adamantane skeleton is disclosed in JP-A-4-39665 and JP-A-5-265212. Similarly, the use of a norbornane skeleton is disclosed in JP-A-5-80515 and JP-A-5-257284.
No. 6,086,045. In addition to these structures,
The effectiveness of general alicyclic structures such as tricyclodecanyl groups is disclosed in JP-A-7-28237 and JP-A-8-259626.

JP-A-8-82925 states that a compound having a terpenoid skeleton such as a menthyl group is transparent in a far ultraviolet region including a wavelength of 193 nm, and can impart dry etching resistance to a resist material. JP-A-8-158
No. 65 discloses that for the same purpose, the dry etching resistance can be increased by mixing a substituted androstane compound with a composition using a polymer matrix that does not necessarily have high dry etch resistance.

A polymer having a chemical structure transparent in a deep ultraviolet region including a wavelength of 193 nm of an ArF excimer laser,
With respect to the resist material which is made to be aqueous alkali developable, it is disclosed in JP-A-4-39665, JP-A-4-184345, JP-A-4-226461, JP-A-5-80515 and the like. In addition, attempts have been made to utilize the carboxylic acid structure of acrylic acid or methacrylic acid. JP-A-8-259626 discloses a polymer compound in which a carboxylic acid group is added to an alicyclic structure introduced into a methacrylic ester side chain.

On the other hand, as one of the resist process technologies for realizing high-precision fine processing, a phase shift exposure method capable of forming a pattern finer than the exposure wavelength has been proposed.
The phase shift exposure method is mainly used to form a wiring pattern. However, there is a pattern arrangement that cannot be realized with a positive resist due to limitations on optical principles, and a negative resist is required. The resins and photosensitive compositions disclosed in the above-mentioned conventional examples are all positive resists, and carboxylic acids having excellent transparency and sufficient dry etching resistance in a far ultraviolet region including a wavelength of 193 nm of an ArF excimer laser. A negative resist with sufficient sensitivity using a system resin has not been obtained.

[0010]

SUMMARY OF THE INVENTION The present invention provides a negative pattern forming material and a method for forming a pattern, which are transparent in the deep ultraviolet region including the wavelength of 193 nm of an ArF excimer laser, have high dry etching resistance, and are soluble in aqueous alkali. The purpose is to provide.

A further object of the present invention is to provide a method for manufacturing a semiconductor device having excellent resolution performance by a phase shift method using an ArF excimer laser light source by utilizing the pattern forming material.

[0012]

The object of the present invention is to provide (a) an alkali-soluble resin containing a carboxylic acid in a side chain, (b) a compound which generates an acid upon irradiation with active actinic radiation, and (c) an aqueous alkali solution by an acid-catalyzed reaction. On the other hand, it can be achieved by a pattern-forming material containing a compound having a reactivity that reduces solubility. At this time, as an example of the aqueous alkali-soluble resin containing the carboxylic acid of the component (a) in the side chain, a resin represented by the structural formula (Formula 1) can be used.

[0013]

Embedded image

Wherein X is a derivative of an aliphatic hydrocarbon compound having a carboxylic acid structure in the side chain or a derivative of a cycloaliphatic hydrocarbon compound, and Y is a derivative of an aliphatic hydrocarbon compound or a cycloaliphatic hydrocarbon compound. Is a derivative of Further, m and n are positive integers, and m + n = 100.

As an example of the derivative of the cycloaliphatic hydrocarbon compound having a carboxylic acid structure in the side chain, a resin in which a carboxylic acid group has been added to the cycloaliphatic hydrocarbon compound introduced into the methacrylic ester side chain can be mentioned. It is also possible to use an alkali-soluble resin containing a carboxylic acid other than the above in the side chain.

Examples of the compound which generates an acid by the actinic actinic radiation of the component (b) include various diazonium salts, various onium salts, esters of a compound containing a plurality of phenolic hydroxyl groups with alkylsulfonic acid, various halogen compounds Is mentioned. Examples of the counter anion of the salt in the present invention include Lewis acids such as tetrafluoroboric acid, hexafluoroantimonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, and toluenesulfonic acid. It is also possible to use compounds other than those described above that generate an acid upon irradiation with active actinic radiation.

The compound having the reactivity of reducing the solubility in an aqueous alkali solution by the acid-catalyzed reaction of the component (c) includes a derivative of an aliphatic hydrocarbon compound having at least one alcoholic hydroxyl group or a cycloaliphatic compound. Derivatives of hydrocarbon compounds are preferred. For example, 1-adamantanol, 2-methyl-2-adamantanol, exo
-Norborneneol, endo- norborneneol,
Secondary or tertiary alcohol compounds having a cyclic aliphatic hydrocarbon skeleton, such as 1,2-cyclohexanediol and 1,4-dioxane-2,3-diol. It is also possible to use a derivative of an aliphatic hydrocarbon compound having at least one alcoholic hydroxyl group other than the above or a derivative of a cycloaliphatic hydrocarbon compound.

In the present invention, an active actinic ray irradiated at the time of pattern formation includes an electron beam, an X-ray, and an ultraviolet ray. As the ultraviolet light source, a KrF excimer laser having a wavelength of 248 nm can be used. Far ultraviolet light with a wavelength of 200 nm or less
A deuterium lamp, SOR light, ArF excimer laser, or the like can be used as a light source.

[0019]

Next, the present invention will be described in more detail, but the present invention is not limited to these examples.

(Example 1) A resin obtained by adding a carboxylic acid group to a cyclic aliphatic hydrocarbon compound introduced into a methacrylic acid ester side chain represented by the structural formula (Formula 1): 100 parts by weight, 4-dioxane-2,3-diol: 20
Parts by weight and triphenylsulfonium triflate: 5
Parts by weight are dissolved in cyclohexanone to obtain a solid content of about 1
A 5% by weight solution was formulated. A solution having the above composition was dropped on a silicon wafer and spin-coated, and then prebaked at 100 ° C. for 5 minutes to obtain a resist film having a thickness of 0.5 μm. The substrate was irradiated with light from a mercury xenon lamp (600 W) through an interference filter (manufactured by Nippon Vacuum Optical Co., Ltd.) of 250 nm, and then heat-treated at 100 ° C. for 5 minutes. Next, the above substrate was developed with an aqueous solution containing 0.119% by weight of tetramethylammonium hydroxide, and rinsed with pure water.

As a result, a negative resist pattern having an exposure amount of 20 mJ / cm ² or more and a residual film ratio of 1 was obtained. FIG. 1 shows the sensitivity characteristics of the resist material of this embodiment to light having a wavelength of 250 nm. As shown in the figure, a good pattern can be formed at 20 mJ / cm ² .

(Example 2) The resist solution of Example 1 was spin-coated on a silicon substrate treated with hexamethyldisilazane, and then heat-treated at 100 ° C for 2 minutes to form a resist having a thickness of 0.50 µm. A film was formed. This was exposed to a fine pattern using a KrF excimer laser stepper (NA 0.45). After the exposure, baking was performed at 100 ° C. for 2 minutes. The development was performed with an aqueous solution of tetramethylammonium hydroxide (0.119% by weight) at 23 ° C. for 90 seconds, followed by rinsing with pure water for 60 seconds. As a result, when the exposure amount was 20 mJ / cm ² , only the unexposed portion of the resist film was dissolved and removed in the developing solution, and a negative 0.2 μm line and space pattern was obtained.

(Example 3) A substrate coated with the resist of Example 1 was placed in an exposure experiment apparatus in which the inside of the apparatus was replaced with nitrogen, and a mask on which a pattern of chrome was drawn on a quartz plate was adhered thereon. . The mask was irradiated with ArF excimer laser light through the mask, and then baked after exposure at 100 ° C. for 2 minutes. Developing with tetramethylammonium hydroxide aqueous solution
(0.119% by weight) at 23 ° C. for 120 seconds, followed by rinsing with pure water for 60 seconds. As a result, the exposure amount is 30 m
At J / cm ² , only the unexposed portions of the resist film were dissolved and removed in the developing solution to obtain a negative 0.25 μm line and space pattern.

(Embodiment 4) A pattern forming material having the composition used in Embodiment 1 is dropped and spin-coated on a substrate on which an aluminum film is formed by performing a predetermined process, and then prebaked at 100 ° C. for 5 minutes to form a film. A 0.5 micron thick resist film was obtained. This substrate has a 248 nm wavelength K through a phase shift mask.
After irradiation with rF excimer laser light, heat treatment was performed at 100 ° C. for 5 minutes. Next, the substrate was developed with an aqueous solution containing 0.119% by weight of tetramethylammonium hydroxide,
Rinse with pure water. As a result, a favorable negative line-and-space pattern could be obtained.

Using the resist pattern formed on the substrate as a mask, the underlying aluminum film was dry-etched under predetermined conditions using a gas containing chlorine gas and boron trichloride gas. Next, the resist pattern was removed to form a desired aluminum wiring pattern. As a result of observation with a scanning electron microscope, a favorable aluminum wiring pattern having a processing dimension of 0.4 μm was able to be formed.

[0026]

According to the present invention, far ultraviolet rays, electron beams, X
Thus, a negative pattern-forming material having high transmittance to dry actinic rays, having high resistance to dry etching, high sensitivity, and being developable with an alkaline aqueous solution was obtained.

[Brief description of the drawings]

FIG. 1 illustrates a pattern forming material 250n according to an embodiment of the present invention.
The figure which shows m light sensitivity characteristic.

[Explanation of symbols]

 1: light sensitivity characteristic curve

Continued on the front page (72) Inventor Ryoko Yamanaka 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (9)

[Claims] 1. A pattern forming material for forming a coating film,
An aqueous alkali-soluble resin containing a carboxylic acid in a side chain, a compound that generates an acid by irradiation with actinic radiation, and a compound that has at least a compound having reactivity to reduce the solubility of the coating film in an aqueous alkali solution by an acid-catalyzed reaction A pattern forming material characterized by the following. 2. The pattern-forming material according to claim 1, wherein said resin is an aqueous alkali-soluble resin having a cyclic aliphatic hydrocarbon skeleton in a polymerized unit and containing a carboxylic acid in a side chain. 3. The pattern-forming material according to claim 1, wherein the compound that generates an acid upon irradiation with actinic radiation is an onium salt, a sulfonate compound or a halogen compound. 4. The compound according to claim 1, wherein the compound having reactivity to reduce the solubility of the coating film in an aqueous alkali solution is a derivative of an aliphatic hydrocarbon compound having at least one alcoholic hydroxyl group or a cyclic aliphatic hydrocarbon. A pattern-forming material that is a derivative of a hydrogen compound. 5. The method according to claim 1, further comprising the steps of:
A step of forming a coating film made of the pattern-forming material according to any one of the items, a step of irradiating the coating film with an actinic radiation to form a predetermined pattern latent image, and developing the coating film with an aqueous alkali solution. A pattern forming method comprising a step of forming a predetermined negative pattern on a coating film. 6. The pattern forming method according to claim 5, wherein said actinic radiation is far ultraviolet light having a wavelength of 250 nm or less. 7. The pattern forming method according to claim 5, wherein said actinic radiation is far ultraviolet light having a wavelength of 220 nm or less. 8. The pattern forming method according to claim 5, wherein said active radiation is an ArF excimer laser having a wavelength of 193 nm. 9. A method for manufacturing a semiconductor device using the pattern forming method according to claim 6, wherein the irradiation of the active radiation is irradiation through a phase shift mask of a predetermined pattern. A method for manufacturing a semiconductor device, comprising: