JPH09311451A - Pattern forming material and pattern forming method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high resolution pattern by incorporating an alkali-soluble polymer, an acid precursor forming halogen acid when irradiated with active chemical rays and a specified onium compd. SOLUTION: This pattern forming material contains an alkali-soluble polymer, an acid precursor forming halogen acid when irradiated with active chemical rays and one of onium compds. represented by formulae I, II, etc., preferably by 100 pts.wt., 1-30 pts.wt. and 1-30 pts.wt., respectively. In the formulae I, II, each of R1 -R3 is H, <=5C alkyl, phenyl, etc., and X<-> is an anion such as a hexafluoroantimonate anion or a hexafluoroarsenate anion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming material used for microfabrication of a semiconductor device and the like and a pattern forming method using the same, and more particularly to a pattern latent pattern formed by pattern irradiation of active chemical rays such as electron beams and ultraviolet rays. The present invention relates to a pattern forming material and a pattern forming method which generate an acid in an image portion, change the solubility of the irradiated portion in an alkaline aqueous solution, and expose a pattern in a developing step.

[0002]

2. Description of the Related Art An acid is generated in a pattern latent image forming portion by a pattern irradiation of an actinic ray such as an electron beam and an ultraviolet ray, and the acid-catalyzed reaction changes the solubility of the irradiation portion in a developing solution. As for the pattern forming material which makes a negative pattern appear in the developing step and the pattern forming method using the same, those described in JP-A-62-164045 and JP-A-2-217855 are known. . This includes a medium that undergoes a crosslinking reaction under an acid catalyst and an acid precursor that produces an acid upon irradiation with radiation. As the acid precursor of this pattern forming material, organic halides such as halogenated isocyanurate and trichloromethylated compounds are described in the above-mentioned conventional examples. As the acid precursor, an s-triazine compound produces an acid very efficiently.

[0003]

The conventionally known pattern-forming material containing an organic halide as an acid precursor produces a highly volatile acid such as hydrogen chloride or hydrogen bromide upon irradiation with active actinic rays. Therefore, there is a problem that the residual film thickness is reduced and the pattern is thinned when the pattern is formed. Further, since hydrogen chloride and hydrogen bromide have a large diffusion in the coating film, there is a problem that it is difficult to form a high resolution pattern by a pattern forming material using a halogen compound as an acid precursor.

An object of the present invention is to overcome the above-mentioned problems of the prior art and to efficiently generate an acid in a pattern latent image forming portion by patternwise irradiation of active chemical rays such as electron beams and ultraviolet rays.
This acid-catalyzed reaction changes the solubility of the irradiated part in an alkaline aqueous solution, and a step of using an industrially advantageous alkaline aqueous solution as a developer to form a pattern forming material having a high resolution pattern. And a pattern forming method using the same.

[0005]

The above object is selected from alkali-soluble polymers, acid precursors that generate an acid upon irradiation with active actinic radiation, and groups represented by the following general formulas (1) to (4). And a pattern forming material containing at least one kind of onium compound, and a pattern forming method using the pattern forming material.

[0006]

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[0007]

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[0008]

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[0009]

[Chemical 12]

(Here, R1 to R4 represent hydrogen, an element selected from the group consisting of an alkyl group having 5 or less carbon atoms, a phenyl group and a t-butylphenyl group, or an atomic group. X ⁻ is hexafluoro. Antimonate, hexafluoroarsenate, tetrafluorophosphate, tetrafluoroborate, toluenesulfonate, trifluoroacetate, trifluoromethanesulfonate,
Represents an anion selected from the group consisting of perchlorate. R1 and R2 may be the same or different. R5 represents any of an acenaphthyl group, a phenacyl group and a phenylphenacyl group. ) Examples of the onium compound used in the present invention include diphenyliodonium chloride, diphenyliodonium bromide, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium toluenesulfonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium perchlorate,
Bis (tert-butylphenyl) iodonium trifluoromethanesulfonate, di (methylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium chloride, triphenylsulfonium bromide, triphenylsulfonium toluenesulfonate,
Triphenylsulfonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perchlorate,
Tetra-n-butylammonium bromide, tetra-n-butylammonium perchlorate, tetra-n-butylammonium hexafluoroantimonate, phenacyltetramethylenesulfonium bromide, phenacyltetramethylenesulfonium hexafluoroantimonate, phenacyltetramethylenesulfonium Trifluoromethanesulfonate, phenylphenacyltetramethylenesulfonium bromide, phenylphenacyltetramethylenesulfonium hexafluoroantimonate,
Examples thereof include phenylphenacyl tetramethylene sulfonium trifluoromethane sulfonate, acenaphthyl tetramethylene sulfonium bromide, acenaphthyl tetramethylene sulfonium hexafluoroantimonate, acenaphthyl tetramethylene sulfonium trifluoromethane sulfonate, and acenaphthyl tetramethylene sulfonium toluene sulfonate.

As the acid precursor, for example, at least one compound selected from the group represented by the following general formulas (5) to (8) is preferable.

[0012]

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[0013]

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[0014]

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[0015]

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Preferred alkali-soluble polymers in the present invention include novolac resin, m, p-cresol novolac resin, halogenated novolac resin, polyhydroxystyrene, halogenated polyhydroxystyrene, or hydroxystyrene / styrene copolymer, poly A polymer compound such as methylglutarimide may be mentioned. Among these, it is desirable to use m, p-cresol novolac resin, and the meta: para ratio is 30:70 to 70:30.
Are more preferable.

In the present invention, the composition ratio of the alkali-soluble polymer, the acid precursor that produces an acid upon irradiation with actinic radiation, and the onium compound is in the range of 100 parts by weight, 1 to 30 parts by weight, and 1 to 30 parts by weight. Is desirable.

The acid precursor used in the present invention produces a radical upon irradiation with an actinic ray such as an electron beam or an ultraviolet ray, and when a hydrogen source is present, the hydrogen is extracted to produce a hydrogen halide. The onium compound used in the present invention itself generates an acid by irradiation with active rays such as electron beams and ultraviolet rays,
Its generation efficiency is lower than that of the acid precursor according to the present invention.
The onium compound used in the present invention is rapidly ionized in the composition and undergoes ion exchange with the acid generated from the acid precursor. As a result, an acid having a larger molecular size than hydrogen halide and less likely to diffuse is efficiently generated according to the amount of the onium compound added. Therefore, the deterioration of the pattern shape due to volatilization and diffusion does not occur, and a highly sensitive and high-resolution pattern can be formed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

<Example 1> m, p- cresol novolac resin, melamine resin (manufactured by Mitsui Cyanamid: Cymel 300),
2- (3 ', 4', 5'-trimethoxystyryl) -4,4
6-bis (trichloromethyl) -1,3,5-triazine and acenaphthyltetramethylenesulfonium trifluoromethanesulfonate were dissolved in cyclohexanone in a weight ratio of 100: 10: 1: 3. This was filtered using a Teflon membrane filter having a pore size of 0.2 μm to obtain a resist solution.

FIG. 1 shows the sensitivity curves of the resist before and after the addition of acenaphthyltetramethylenesulfonium trifluoromethanesulfonate upon electron beam irradiation. According to FIG.
It can be seen that the contrast is improved by the addition of acenaphthyl tetramethylene sulfonium trifluoromethane sulfonate.

A resist solution having the above composition was dropped on a silicon substrate, spin-coated and then heat-treated at 100 ° C. for 2 minutes to form a resist film having a thickness of 1.0 μm. 280 mJ / cm ² exposure using an i-line reduction projection exposure apparatus, then 90 ° C.,
It was heat-treated for 1.5 minutes to accelerate the crosslinking reaction in the resist. After heat treatment, tetramethylammonium hydroxide 2.
When development was carried out for 250 seconds with an aqueous solution containing 38% by weight, a fine pattern of 0.275 μm could be formed.

According to the pattern forming method using the pattern forming material of this embodiment, 2- (3 ', 4', 5'-trimethoxystyryl) -4,6-bis (trichloromethyl)-
Since hydrogen chloride generated from 1,3,5-triazine is ion-exchanged with acenaphthyltetramethylenesulfonium trifluoromethanesulfonate to generate trifluoromethanesulfonic acid which is difficult to diffuse, a high-resolution pattern can be formed. This makes it possible to improve the yield when manufacturing integrated circuits, which is industrially advantageous.

Example 2 m, p-cresol novolac resin, melamine resin (manufactured by Mitsui Cyanamid: Cymel 300), 2- (3 ', 4', 5'-trimethoxystyryl) -4,6-bis ( Trichloromethyl) -1,3,5-
Triazine and triphenylsulfonium trifluoromethanesulfonate were dissolved in cyclohexanone in a weight ratio of 100: 10: 1: 3. This is 0.2μ
m 2 Teflon membrane filter was used to obtain a resist solution.

A resist solution having the above composition was dropped on a silicon substrate, spin-coated and then heat-treated at 100 ° C. for 2 minutes to form a resist film having a thickness of 1.0 μm. 350 mJ / cm ² exposure using an i-line reduction projection exposure apparatus, then 90 ° C.
It was heat-treated for 1.5 minutes to accelerate the crosslinking reaction in the resist. After heat treatment, tetramethylammonium hydroxide 2.
When developed with an aqueous solution containing 38% by weight for 250 seconds, a 0.3 μm fine pattern could be formed.

According to the pattern forming method using the pattern forming material of this embodiment, 2- (3 ', 4', 5'-trimethoxystyryl) -4,6-bis (trichloromethyl)-
Since hydrogen chloride generated from 1,3,5-triazine is ion-exchanged with triphenylsulfonium trifluoromethanesulfonate to generate trifluoromethanesulfonic acid which is difficult to diffuse, a high-resolution pattern can be formed. This makes it possible to improve the yield when manufacturing integrated circuits, which is industrially advantageous.

<Example 3> m, p-cresol novolac resin, melamine resin (Mitsui Cyanamid: Cymel 300), 2- (3 ', 4', 5'-trimethoxystyryl) -4,6-bis ( Trichloromethyl) -1,3,5-
Triazine and diphenyliodonium trifluoromethanesulfonate were dissolved in cyclohexanone in a weight ratio of 100: 10: 1: 3. This has a pore size of 0.2 μm
It filtered using the Teflon membrane filter of No. 2, and the resist solution was obtained.

A resist solution having the above composition was dropped on a silicon substrate, spin-coated and heat-treated at 100 ° C. for 2 minutes to form a resist film having a thickness of 1.0 μm. 370 mJ / cm ² exposure using an i-line reduction projection exposure apparatus, then 90 ° C.
It was heat-treated for 1.5 minutes to accelerate the crosslinking reaction in the resist. After heat treatment, tetramethylammonium hydroxide 2.38
When developed with an aqueous solution containing a weight percentage for 250 seconds, a fine pattern of 0.3 μm could be formed.

According to the pattern forming method using the pattern forming material of this embodiment, 2- (3 ', 4', 5'-trimethoxystyryl) -4,6-bis (trichloromethyl)-
Since hydrogen chloride generated from 1,3,5-triazine is ion-exchanged with diphenyliodonium trifluoromethanesulfonate to generate trifluoromethanesulfonic acid which is difficult to diffuse, a high resolution pattern can be formed. This makes it possible to improve the yield when manufacturing integrated circuits, which is industrially advantageous.

Example 4 FIG. 2 shows a pattern forming method using the pattern forming material of the present invention in the order of steps. FIG.
As shown in (a), an aluminum film 2 is formed on a semiconductor substrate 1, and a resist film 3 is formed thereon. As shown in FIG. 2B, energy rays 5 pass through the mask 4.
The resist film 3 is irradiated with and a resist pattern is obtained as shown in FIG. A dry etching process is performed through this pattern as shown in FIG. 3D, and then the resist film is removed by ashing.
A wiring pattern could be obtained as shown in (e).

[0030]

According to the pattern forming material and the pattern forming method of the present invention, it is possible to efficiently form a high resolution pattern.

[Brief description of drawings]

FIG. 1 is a graph showing a sensitivity curve of a resist composition according to an example of the present invention.

FIG. 2 is an explanatory view of a pattern forming method using the pattern forming material of the present invention.

[Explanation of symbols]

1 ... Semiconductor substrate, 2 ... Aluminum film, 3 ... Resist film, 4 ... Mask, 5 ... Energy ray, 6 ... Latent image.

Claims (4)

[Claims] 1. An alkali-soluble polymer, an acid precursor that produces a halogen acid by irradiation with actinic radiation, and at least one kind of onium selected from the group represented by the following general formulas (1) to (4). A pattern forming material comprising a compound. Embedded image Embedded image Embedded image Embedded image (Here, R1 to R4 represent an element or atomic group selected from the group consisting of hydrogen, an alkyl group having 5 or less carbon atoms, a phenyl group, and a tbutylphenyl group. X ⁻ represents hexafluoroantimonate, hexa Represents an anion selected from the group consisting of fluoroarsenate, tetrafluorophosphate, tetrafluoroborate, toluenesulfonate, trifluoroacetate, trifluoromethanesulfonate, perchlorate, R1 to R
2 may be the same or different. R5 represents any of an acenaphthyl group, a phenacyl group and a phenylphenacyl group. ) 2. The pattern forming material according to claim 1, which is selected from the group represented by the following general formulas (5) to (8) as an acid precursor which produces a halogen acid upon irradiation with active actinic radiation. A pattern forming material characterized by using one kind of compound. Embedded image [Chemical 6] [Chemical 7] Embedded image 3. The pattern forming material according to claim 1, wherein the alkali-soluble polymer, an acid precursor which produces an acid by irradiation with actinic radiation, and the general formulas (1) to (4) The composition ratio of at least one kind of onium compound selected from the group represented by (4) is in the range of 100 parts by weight, 1 to 30 parts by weight, and 1 to 30 parts by weight. 4. A step of forming a coating film by applying the pattern forming material according to any one of claims 1 to 3 on a substrate, and using an actinic ray such as electron beam or ultraviolet ray for the coating film. To form a predetermined pattern latent image, to accelerate the reaction of changing the solubility of the pattern latent image forming portion in the alkaline aqueous solution, to develop the predetermined pattern using the alkaline aqueous solution as a developer, and A pattern forming method comprising a step of processing the organic resin layer with an etching medium using the pattern as a mask.