JPH09230606A - Fine pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the dimensional accuracy of a resist pattern by supplying metal alcoxide to the surface of a resist film, and forming a thick oxide film on the surface of the photo-exposure part of the resist film. SOLUTION: A resist film 11 is produced on a semiconductor base board 10 using a chemically amplified resist which emits acids when irradiated with KrF excimer laser and reacts with the acids. When irradiation with KrF excimer laser 13 is made using a mask 12, acids are produced on the surface of the exposure part 11a of the resist film 11, thereby turning the surface of the photo- exposure part 11a hydrophilic. If water vapor 14 is supplied to the surface of the resist film 11, the water spreads into the exposure part 11a from its surface till a deeper place. When a vapor 15 of methyl-triethoxysilane is sprayed over the surface of the resist film 11 in the air of a relative humidity of 95%, an oxide film 16 having a large film thickness is formed selectively on the surface of the exposure part 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine pattern forming method for manufacturing a semiconductor integrated circuit device or the like.

[0002]

2. Description of the Related Art Hitherto, in the manufacture of ICs or LSIs, patterns have been formed by photolithography using ultraviolet rays, but with the miniaturization of semiconductor elements, the use of short-wavelength light sources has been promoted. When a short-wavelength light source is used, a chemically amplified resist capable of obtaining high sensitivity and high resolution has been used as a resist to be used (for example, O. NALAMASU et a).
l. Proc. SPIE, 1262, 32 (199
0)).

A chemically amplified resist is a multi-component substance containing an acid generator that generates an acid when irradiated with an energy beam, and a polymer or a monomolecular compound that reacts with the acid. As a polymer compound which reacts with an acid, for example, a compound having a structure as shown in the following [Chemical Formula 1] is known.

[0004]

Embedded image

In the chemical formula 1, R is an alkoxycarbonyl group, an alkyl group, an alkoxyalkyl group, an alkylsilyl group, a tetrahydropyranyl group, an alkoxycarbonylmethyl group or the like, which easily causes a decomposition reaction by an acid. is there. Thus, the chemically amplified resist is
Since the main component is a polymer compound having a low absorption rate in the short wavelength region such as a polyvinylphenol derivative, the transparency of the resist increases, and the resist reaction proceeds by an acid-catalyzed chain reaction, and has high sensitivity. In addition, since it is excellent in resolution, it is regarded as a promising material for forming a fine pattern using a short wavelength light source.

As described above, the formation of a resist pattern of 0.2 μm or less has been actively studied at present by the deep ultraviolet exposure method using a chemically amplified resist. As a result, the conventional wet developing method has the following problems. That is, after irradiating the resist film coated on the semiconductor substrate with far ultraviolet rays and exposing, developing is performed to form a resist pattern, and then the developing solution and the resist material dissolved in the developing solution are washed away with pure water, Finally, the resist pattern is spun dry by rotating at a high speed.

However, as shown in FIG. 16A, in the step of drying the resist pattern, in a portion having a high aspect ratio, a large surface of pure water 82 is formed between the resist patterns 81 formed on the semiconductor substrate 80. Tension acts, and as shown in FIG. 16B or 16C, a phenomenon occurs in which the resist patterns 81 bend or break, and the resist patterns lean toward each other. This phenomenon is the same even when a normal resist other than the chemically amplified resist is used.

Therefore, as disclosed in US Pat. No. 5,278,029, a method of forming a resist pattern by performing dry etching on a chemically amplified resist film has been proposed. Hereinafter, this method will be described with reference to FIG.
7 (a) and 7 (b) and FIGS. 18 (a) and 18 (b).

First, as shown in FIG. 17A, a chemically amplified resist film 91 applied on a semiconductor substrate 90 is formed.
KrF excimer laser 93 using a mask 92
Is irradiated, acid is generated in the exposed portion 91 a of the resist film 91. The exposed portion 91a changes to hydrophilic by the action of the acid and easily adsorbs water in the atmosphere, so that a natural water absorbing layer 94 of thin water is formed on the surface of the exposed portion 91a.

Next, when an alkoxysilane gas is introduced into the surface of the resist film 91, as shown in FIG.
An oxide film 95 is formed on the surface of the exposed portion 91a. Thereafter, when dry etching is performed on the resist film 91 by RIE using the O ₂ plasma 96 using the oxide film 95 as a mask, a fine resist pattern 97 is formed as shown in FIG. is there.

[0011]

However, when a resist pattern is formed by the above-described method, as shown in FIG. 19, the oxide film 95 flows in the alcohol volatilization step, and the edge roughness of the oxide film 95 is reduced. The size of the resist pattern becomes large, and the dimensional accuracy of the resist pattern is degraded. As a result of studying the cause, it has been found that the shape of the oxide film 95 is disordered due to the thinness of the oxide film 95.

In view of the above, according to the present invention, it is possible to form a thick oxide film on an exposed portion of a resist film by supplying a metal alkoxide to the surface of the resist film, thereby improving the dimensional accuracy of the resist pattern. The purpose is to improve.

[0013]

Means for Solving the Problems In order to achieve the above object, the present inventors have studied the cause of forming only an oxide film having a small thickness when an alkoxysilane gas is supplied to the surface of an exposed portion. I found the following: That is, in a clean room environment, since the relative humidity is kept low at 50% or less, moisture in the air hardly diffuses into the resist film and only diffuses to the surface of the resist film. Therefore, if the exposed portion of the resist film is left alone in the air, the thickness of the oxide film formed on the surface of the exposed portion of the resist film becomes small. The present invention has been made based on the above findings, and in the exposed portion of the resist film,
After absorbing water, water and a metal alkoxide are supplied to form a thick metal oxide film.

Specifically, the means for solving the problems according to the invention of claim 1 is to form a resist film by applying a resist containing a compound that crosslinks when irradiated with an energy beam to a fine pattern forming method. And a second step of irradiating the resist film with an energy beam to crosslink the exposed portion of the resist film, and supplying a silylating agent to the surface of the resist film to remove the resist film. A third step of forming a silylated layer on the unexposed portion, a fourth step of irradiating the silylated layer with a high energy beam, and a step of forming the silylated layer irradiated with the high energy beam as a mask on the resist film. And a fifth step of forming a resist pattern by etching.

Specifically, the means for solving the problems according to the second aspect of the present invention is to provide a fine pattern forming method, which comprises a first step of applying a resist film on a semiconductor substrate and a pattern exposure of the resist film. 2 step, a third step of developing the exposed resist film with a developing solution to form a resist pattern, and the developing solution and the resist material dissolved in the developing solution with a rinse solution containing a surfactant. And a fourth step of cleaning and removing.

According to a third aspect of the invention, in addition to the structure of the second aspect, the surfactant contained in the rinse liquid in the fourth step is limited to polyoxyethylene propylene glycol.

According to a fourth aspect of the present invention, in the structure according to the second or third aspect, the resist film in the first step has at least one of an acid generator that generates an acid when irradiated with an energy beam and a phenolic hydroxyl group. A chemical amplification type resist containing a compound whose part is substituted by a protecting group which is eliminated by an acid is added.

The invention of claim 5 adds to the structure of claim 4 a structure comprising a step of heating the exposed resist film between the second step and the third step. It is a thing.

[0019]

When the silylated layer formed on the non-exposed portion of the resist film is irradiated with a high-energy beam, the carbon compound constituting the silylated layer is oxidized and decomposed to cause volatilization of the carbon compound. , The silicon density of the silylated layer is increased.

According to the second aspect of the present invention, since the developing solution and the resist material dissolved in the developing solution are washed and removed by the rinsing solution containing the surfactant, the rinsing solution acting between the fine resist patterns is removed. Surface tension is reduced.

According to the fifth aspect of the present invention, since the step of heating the resist film made of the chemically amplified resist is provided, the action of removing the protective group by the acid is activated, and the development reaction of the resist film is accelerated. .

[0022]

【Example】

(First Embodiment) FIGS. 1A to 1C and 2A,
(B) is sectional drawing which shows each process of the fine pattern formation method which concerns on 1st Example of this invention.

The chemically amplified resist contains an acid generator which generates an acid when irradiated with an energy beam and a compound which reacts with the acid, for example, 1, 2, 3, 4-as the acid generator. Tetrahydronaphthylidene imino p
-Use a copolymer of styrene sulfonate (NISS) and methyl methacrylate (MMA).

First, as shown in FIG. 1 (a), the chemically amplified resist is spin-coated on a semiconductor substrate 10 made of silicon, and heated at 90 ° C. for 60 seconds to give a film thickness of 1 A resist film 11 having a thickness of 0.2 μm is formed. Thereafter, by irradiating a KrF excimer laser 13 as an energy beam using the mask 12,
The pattern of the mask 12 is exposed on the resist film 11. In this way, the NISS is decomposed on the surface of the exposed portion 11a of the resist film 11 to generate an acid, and the acid changes the surface of the exposed portion 11a of the resist film 11 to hydrophilic.

Next, as shown in FIG. 1B, the semiconductor substrate 10 is kept in air at a relative humidity of 95% at a temperature of 30 ° C. for 30 minutes, so that the water vapor 14 is formed on the surface of the resist film 11. Supply. In this way, the water vapor 14 is adsorbed on the surface of the exposed portion 11a of the resist film 11,
Water diffuses from the surface of the exposed portion 11a of the resist film 11 to a deep portion, for example, a portion of 100 nm.

Next, as shown in FIG. 1C, methyltriethoxysilane (MTEOS) as a metal alkoxide is used in a state where the semiconductor substrate 10 is kept in air at a relative humidity of 95% at a temperature of 30 ° C. When the vapor 15 is sprayed on the surface of the resist film 11 for 3 minutes,
The oxide film 16 is selectively formed on the surface of the exposed portion 11a. In this case, acid (H +) generated by decomposition of NISS
Becomes a catalyst and a reaction as shown in [Chemical Formula 2] occurs.
Oxide film 16 is formed and alcohol is also generated.

Further, in the step shown in FIG. 1B, the water vapor 14 is supplied to the resist film 11, and the water is diffused from the surface of the exposed portion 11a of the resist film 11 to the deep portion. Since the growth proceeds inside the resist film 11, the oxide film 16 having a large film thickness can be formed. Further, in the step shown in FIG.
Since MTEOS is supplied to the resist film 11 in air at a relative humidity of 95%, evaporation of water absorbed by the resist film 11 is prevented, and water necessary for forming the oxide film 16 is supplied. Is maintained, an oxide film 16 having a sufficient thickness to withstand RIE (reactive ion etching) of O ₂ plasma described later can be formed.

[0028]

Embedded image

Next, the resist film 11 is heated at a temperature of 90 ° C. for 60 seconds to volatilize the generated alcohol and unreacted water, as shown in FIG. Cure 16 In this way, as shown in FIG. 3A, the oxide film 16 retains its original shape.

[Table 1] shows the relationship between the supply time of water vapor, the diffusion depth of water and the edge roughness of the resist pattern. From [Table 1], it can be seen that the diffusion depth of water is 100 nm or more. It can be seen that the edge roughness of the resist pattern is good. As described above, by controlling the diffusion depth of water, the dimensional accuracy of the resist pattern can be improved.

[0031]

[Table 1]

Next, as shown in FIG. 2B, R ₂ is formed by using O ₂ plasma 17 with the cured oxide film 16 as a mask.
By performing IE, a resist pattern 18 is formed. In this case, the RIE conditions of the O ₂ plasma were such that a parallel plate type RIE apparatus was used, and the power was 900 W, the pressure was 0.7 Pa, and the flow rate was 40 SCCM.

FIG. 3B shows a 0.2 μm line-and-space pattern exposed by a KrF excimer laser stepper with NA: 0.42 using a Levenson type phase shift mask by the fine pattern forming method described above. The pattern shape when the resist pattern 18 is formed is shown. In this case, the thickness of the resist film 11 is 1.2 μm
Thus, the resist pattern 18 having a high aspect ratio of aspect ratio: 6 or more could be formed.

As described above, according to the first embodiment, the oxide film 16 is selectively formed on the surface of the resist film 11, and the resist film 11 is subjected to RIE of O ₂ plasma using the oxide film 16 as a mask. Since the dry development is performed on-the-fly, there is no problem of pattern collapse due to the wet development, and since the shape of the oxide film 16 can be maintained well, a fine pattern with a high aspect ratio can be formed with high accuracy. Also,
In the step of diffusing water into the exposed portion 11a of the resist film 11, the time for supplying the water vapor 14, that is, the semiconductor substrate 10
Is maintained in air at a temperature of 30 ° C. and a relative humidity of 95%, the depth of diffusion of water can be controlled.

In the first embodiment, a copolymer of NISS and MMA was used as the chemically amplified resist, but as the compound that reacts with an acid, polyvinylphenol, novolac resin or the like is used instead of MMA. Instead of NISS, an acid generator that generates sulfonic acid may be used.

Further, as the metal alkoxide vapor, M
Although TEOS was used, other metal alkoxides such as tetramethyl orthosilicate and tetraethyl orthosilicate may be used instead.

Although RIE using O ₂ plasma is used as the dry development method, ECR (electron cyclotron resonance etching) using O ₂ plasma may be used instead of RIE.

Although the KrF excimer laser was used as the exposure light source, an ArF excimer laser or X-rays may be used instead.

Further, in the step of diffusing water on the surface of the exposed portion 11a of the resist film 11, the semiconductor substrate 10 was held in water vapor, but instead of this, the resist film 11 on the semiconductor substrate 10 was exposed to liquid. Water may be supplied. However, it is preferable to supply water in a gaseous state rather than to supply water in a liquid state, since diffusion of water proceeds quickly and the depth of the oxide film 16 increases.

(Second Embodiment) FIGS. 4 (a) to 4 (c) and FIGS. 5 (a) and 5 (b) are sectional views showing respective steps of a fine pattern forming method according to a second embodiment of the present invention. Is.

The chemically amplified resist contains a base generator that generates a base when irradiated with an energy beam, for example, 2-nitrobenzylcarbamate as a base generator and polymethylmethacrylate (PMMA).
Use a mixture with

First, as shown in FIG. 4 (a), a resist made of the chemically amplified resist is spin-coated on a semiconductor substrate 20 made of silicon and heated at a temperature of 90 ° C. for 60 seconds, A resist film 21 having a thickness of 1.2 μm is formed. Thereafter, the pattern of the mask 22 is exposed on the resist film 21 by irradiating a KrF excimer laser 23 as an energy beam using the mask 22. In this manner, 2-nitrobenzyl carbamates are decomposed on the surface of the exposed portion 21a of the resist film 21 to generate an amine (base), and the amine changes the surface of the exposed portion 21a of the resist film 21 to hydrophilicity. I do.

Next, as shown in FIG. 4B, the semiconductor substrate 20 is kept in air at a relative humidity of 95% at a temperature of 30 ° C. for 30 minutes, so that water vapor 24 is formed on the surface of the resist film 21. Supply. In this way, water diffuses from the surface of the exposed portion 21a of the resist film 21 to a deep portion, for example, a portion of 100 nm.

Next, with the semiconductor substrate 20 kept in the air at a relative humidity of 95% at a temperature of 30 ° C., MT
When the EOS vapor 25 is sprayed on the surface of the resist film 11 for, for example, three minutes, the oxide film 26 is selectively formed on the surface of the exposed portion 21 a of the resist film 21. In this case, the amine (R-NH ₃ ⁺ ) generated by the decomposition of 2-nitrobenzyl carbamates acts as a catalyst to cause a reaction represented by [Chemical Formula 3], thereby forming the oxide film 26. Alcohol is also produced.

[0045]

Embedded image

Next, the resist film 21 is heated at a temperature of 90 ° C. for 60 seconds to volatilize the produced alcohol and unreacted water, as shown in FIG. Harden 26. By doing so, the oxide film 26 retains its original shape.

Next, as shown in FIG. 5B, R ₂ is formed by using O ₂ plasma 27 with the cured oxide film 26 as a mask.
By performing IE, a resist pattern 28 is formed. In this case, the RIE conditions of the O ₂ plasma were such that a parallel plate type RIE apparatus was used, and the power was 900 W, the pressure was 0.7 Pa, and the flow rate was 40 SCCM.

As described above, according to the second embodiment, the oxide film 26 is selectively formed on the surface of the resist film 21, and the oxide film 26 is used as a mask to perform RIE of O ₂ plasma on the resist film 21. Since dry development is performed on-the-fly, there is no problem of pattern collapse due to wet development, and since the shape of the oxide film 26 can be maintained well, a fine pattern with a high aspect ratio can be formed with high accuracy. Also,
In the step of diffusing water into the exposed portion 21a of the resist film 21, the time for supplying the water vapor 24, that is, the semiconductor substrate 20
Is maintained in air at a temperature of 30 ° C. and a relative humidity of 95%, the depth of diffusion of water can be controlled. First
As in the embodiment, 10 minutes from the surface of the resist film 21.
It is preferable that water is diffused to a depth of 0 nm or more because the flow of the oxide film 26 can be prevented.

In the second embodiment, PMMA was used as the compound that reacts with the base constituting the chemically amplified resist, but instead of this, polyvinylphenol or novolac resin may be used as the base generator. Used 2-nitrobenzylcarbamate, but not limited to this.

Further, as the metal alkoxide vapor, M
Although TEOS was used, other metal alkoxides such as tetramethyl orthosilicate and tetraethyl orthosilicate may be used instead.

Although RIE using O ₂ plasma is used as the dry development method, ECR (electron cyclotron resonance etching) using O ₂ plasma may be used instead of RIE.

Although the KrF excimer laser was used as the exposure light source, an ArF excimer laser or an X-ray may be used instead.

Further, in the step of diffusing water on the surface of the exposed portion 21a of the resist film 21, the semiconductor substrate 20 was held in water vapor, but instead of this, the resist film 21 on the semiconductor substrate 20 was exposed to liquid. Water may be supplied.

(Third Embodiment) FIGS. 6A to 6C and FIGS. 7A and 7B are sectional views showing respective steps of a fine pattern forming method according to a third embodiment of the present invention. Is. In the third embodiment, NISS is used as the chemically amplified resist.
And a copolymer of MMA.

First, as shown in FIG. 6A, a resist made of the chemically amplified resist is spin-coated on a semiconductor substrate 30 made of silicon, and heated at 90 ° C. for 60 seconds, A resist film 31 having a thickness of 1.2 μm is formed. Thereafter, the pattern of the mask 32 is exposed on the resist film 31 by irradiating a KrF excimer laser 33 as an energy beam using the mask 32. In this way, the NISS is decomposed on the surface of the exposed portion 31a of the resist film 31 to generate an acid, and the acid changes the surface of the exposed portion 31a of the resist film 31 to hydrophilicity.

Next, as shown in FIG. 6B, water 34 is poured on the surface of the resist film 31 for 30 minutes. By doing so, water diffuses from the surface of the exposed portion 31a of the resist film 31 to a deep portion, for example, a portion of 100 nm.

Next, after spin-drying the surface of the resist film 31, as shown in FIG.
When an alkoxysilane solution 35 as a metal alkoxide is applied for 5 minutes, an oxide film 36 is selectively formed on the surface of the exposed portion 31a of the resist film 31. As the alkoxysilane solution, a mixture of MTEOS at a concentration of 0.2 mol / l and a mixture of hexane and acetone is used.
The mixing ratio of hexane and acetone is 9: 1. Thereafter, the resist film 31 and the oxide film 36 are rinsed with hexane, and then spin-dried. In this case, the acid generated by the decomposition of the NISS acts as a catalyst to cause a reaction as shown in the above [Chemical Formula 2], thereby forming the oxide film 36 and also producing alcohol.

Next, as shown in FIG. 7B, R ₂ is formed by using O ₂ plasma 37 with the cured oxide film 36 as a mask.
By performing IE, a resist pattern 38 is formed. In this case, the RIE conditions of the O ₂ plasma were such that a parallel plate type RIE apparatus was used, and the power was 900 W, the pressure was 0.7 Pa, and the flow rate was 40 SCCM.

As described above, according to the third embodiment, the oxide film 36 is selectively formed on the surface of the resist film 31, and the oxide film 36 is used as a mask to perform RIE of O ₂ plasma on the resist film 31. Since the dry development is performed on-the-fly, there is no problem of pattern collapse due to the wet development, and the shape of the oxide film 36 can be maintained well, so that a fine pattern with a high aspect ratio can be formed with high accuracy. Also,
In the step of diffusing water into the exposed portion 31a of the resist film 31, the depth of diffusion of water can be controlled by the time during which the water 34 is poured on the surface of the resist film 31. As in the first embodiment,
It is preferable that water is diffused from the surface of the resist film 31 to a depth of 100 nm or more, since the flow of the oxide film 36 can be prevented.

In the third embodiment, a copolymer of NISS and MMA was used as the chemically amplified resist, but polyvinylphenol, novolac resin or the like was used as the compound that reacts with acid instead of MMA. Instead of NISS, an acid generator that generates sulfonic acid may be used.

As the metal alkoxide solution, M
Although TEOS was used, other metal alkoxides such as tetramethyl orthosilicate and tetraethyl orthosilicate may be used instead.

Although RIE using O ₂ plasma was used as the dry development method, ECR using O ₂ plasma or the like may be used instead.

Although the KrF excimer laser is used as the exposure light source, an ArF excimer laser or X-ray may be used instead of the KrF excimer laser.

Further, in the step of diffusing water on the surface of the exposed portion 31a of the resist film 31, water was poured on the surface of the resist film 31, but instead of this, the semiconductor substrate 30 was held in water vapor. Good.

(Fourth Embodiment) FIGS. 8A to 8C and FIGS. 9A to 9C are sectional views showing respective steps of a fine pattern forming method according to a fourth embodiment of the present invention. Is. In the fourth embodiment, NISS is used as the chemically amplified resist.
And a copolymer of MMA.

First, as shown in FIG. 8A, a resist of the chemically amplified resist is spin-coated on a semiconductor substrate 40 of silicon and heated at 90 ° C. for 60 seconds, A resist film 41 having a thickness of 1.2 μm is formed. Then, on the resist film 41, 5
Spin-coating a contrast-enhanced resin containing diazomel drum acid and heating at 90 ° C. for 60 seconds to form a resin film 42 having a thickness of 0.1 μm;

Next, as shown in FIG. 8B, the mask 4
By irradiating a KrF excimer laser 44 as an energy beam using 3, a pattern of a mask 43 is exposed on the resist film 41. In this way, the NISS is decomposed on the surface of the exposed portion 41a of the resist film 41 to generate an acid, and the acid changes the surface of the exposed portion 41a of the resist film 41 to hydrophilic. In this case, the 5-diazomeldrum acid contained in the resin film 42 is decomposed by the KrF excimer laser beam 44 and the transmittance for the KrF excimer laser beam 44 increases, so that the resist film 4
The contrast of light intensity on the surface of No. 1 is improved, and an acid is efficiently generated in the exposed portion 41a. Due to the generation of acid, the surface of the exposed portion 41a of the resist film 41 changes to hydrophilic.

Next, as shown in FIG. 8C, the resin film 4
After removing 2, the semiconductor substrate 40 is held in air at a temperature of 30 ° C. and a relative humidity of 95% for a predetermined time, thereby supplying water vapor 45 to the surface of the resist film 41.
In this way, the water vapor 45 is adsorbed on the surface of the exposed portion 41a of the resist film 41, and the exposed portion 41a of the resist film 41 is
Water diffuses from the surface in a to a deep part, for example, a part of 100 nm.

Next, with the semiconductor substrate 40 kept in the air at a relative humidity of 95% at a temperature of 30 ° C., MT
When the EOS vapor 46 is blown onto the surface of the resist film 41 for 3 minutes, the oxide film 47 is selectively formed on the surface of the exposed portion 41a of the resist film 41. In this case, the acid generated by the decomposition of the NISS acts as a catalyst to cause a reaction as shown in the above [Chemical Formula 2], thereby forming an oxide film 47 and also producing an alcohol.

Next, as shown in FIG. 9C, the oxide film 4
A resist pattern 49 is formed by performing RIE using an O ₂ plasma 48 using the mask 7 as a mask. In this case, the RIE conditions for the O ₂ plasma were as follows: a parallel plate type RIE apparatus was used, power: 900 W, pressure: 0.7.
Pa, flow rate: 40 SCCM.

As described above, according to the fourth embodiment, the oxide film 47 is selectively formed on the surface of the resist film 41, and the oxide film 47 is used as a mask to subject the resist film 41 to RIE of O ₂ plasma. Since the dry development is performed on-the-fly, there is no problem of pattern collapse due to the wet development, and since the shape of the oxide film 47 can be maintained well, a fine pattern having a high aspect ratio can be formed with high accuracy. Also,
In the step of diffusing water into the exposed portion 41a of the resist film 41, the time for supplying the water vapor 45, that is, the semiconductor substrate 40
Is maintained in air at a temperature of 30 ° C. and a relative humidity of 95%, the depth of diffusion of water can be controlled. First
As in the embodiment, 10 mm from the surface of the resist film 41.
It is preferable that the water is diffused to a depth of 0 nm or more because the flow of the oxide film 47 can be prevented.

In the fourth embodiment, a copolymer of NISS and MMA was used as the chemically amplified resist, but polyvinylphenol, novolac resin or the like was used as the compound that reacts with acid instead of MMA. Instead of NISS, an acid generator that generates sulfonic acid may be used. Further, as the contrast enhanced resin, a resin containing 5-diazomeldrum acid was used, but another diazoketone or a resin containing diazodiketone may be used instead.

As the metal alkoxide vapor, M
Although TEOS was used, other metal alkoxides such as tetramethyl orthosilicate and tetraethyl orthosilicate may be used instead.

Although RIE using O ₂ plasma was used as the dry development method, ECR using O ₂ plasma or the like may be used instead.

Although the KrF excimer laser was used as the exposure light source, an ArF excimer laser or X-rays may be used instead.

Further, in the step of diffusing water on the surface of the exposed portion 41a of the resist film 41, the semiconductor substrate 40 was held in water vapor, but instead of this, water was applied to the resist film 41 on the semiconductor substrate 40. May be supplied.

(Fifth Embodiment) FIGS. 10A to 10C to 12A and 12B are sectional views showing the steps of a fine pattern forming method according to the fifth embodiment of the present invention. Is. Fifth
In the examples, the chemically amplified resist is NI.
A copolymer of SS and MMA is used.

First, as shown in FIG. 10A, on the semiconductor substrate 50 made of silicon, a resist made of the chemically amplified resist is spin-coated and heated at a temperature of 90 ° C. for 60 seconds, A resist film 51 having a film thickness of 1.2 μm is formed. Thereafter, a pattern of the mask 52 is exposed on the resist film 51 by irradiating a KrF excimer laser 53 as an energy beam using the mask 52. In this way, the NISS is decomposed on the surface of the exposed portion 51a of the resist film 51 to generate an acid, and the acid changes the surface of the exposed portion 51a of the resist film 51 to hydrophilic.

Next, as shown in FIG. 10B, the semiconductor substrate 50 is kept in air at a relative humidity of 95% at a temperature of 30 ° C. for a predetermined time so that water vapor 54 is formed on the surface of the resist film 51. Supply. By doing so, the water vapor 54 is adsorbed on the surface of the exposed portion 51a of the resist film 51, and water is diffused from the surface of the exposed portion 51a of the resist film 51 to a deep portion, for example, a portion of 100 nm.

Next, as shown in FIG. 10C, with the semiconductor substrate 50 kept in the air at a relative humidity of 95% at a temperature of 30 ° C., vapor 55 of MTEOS is applied to the surface of the resist film 51. Spray for 30 seconds, for example. Thus, an oxide film 56 is formed on the surface of the exposed portion 51a of the resist film 51.

Next, as shown in FIG. 11A, dry nitrogen gas 57 is blown onto the surface of the resist film 51 for, eg, 30 seconds to evaporate the alcohol in the oxide film 56. Thereafter, as shown in FIG. 11B and FIG. 12A, the above-mentioned spraying of the vapor 55 of MTEOS and the spraying of the dried nitrogen gas 57 are alternately performed about six times, respectively, so that the exposed portion of the resist film 51 is exposed. All regions 51a are changed to oxide films 56. By alternately supplying the MTEOS vapor 55 and drying with the nitrogen gas 57 a plurality of times as described above, the alcohol that has maintained the fluidity of the oxide film 56 is surely evaporated. Very good.

Next, as shown in FIG. 12B, a resist pattern 59 is formed by performing RIE using O ₂ plasma 58 with the oxide film 56 as a mask.
In this case, the RIE conditions for the O ₂ plasma are as follows, using a parallel plate type RIE apparatus, power: 900 W, pressure: 0.
7 Pa, flow rate: 40 SCCM.

In the fifth embodiment, a copolymer of NISS and MMA was used as the chemically amplified resist, but polyvinylphenol, novolac resin or the like was used as the compound that reacts with acid instead of MMA. Instead of NISS, an acid generator that generates sulfonic acid may be used.

As the metal alkoxide vapor, M
Although TEOS was used, other metal alkoxides such as tetramethyl orthosilicate and tetraethyl orthosilicate may be used instead.

Although RIE using O ₂ plasma is used as the dry development method, ECR using O ₂ plasma or the like may be used instead.

Although the KrF excimer laser is used as the exposure light source, an ArF excimer laser or X-ray may be used instead of the KrF excimer laser.

Further, in the step of diffusing water on the surface of the exposed portion 51a of the resist film 51, the semiconductor substrate 50 was held in water vapor, but instead of this, the resist film 51 on the semiconductor substrate 50 was coated with a liquid. Water may be supplied.

(Sixth Embodiment) FIGS. 13A to 13C and FIGS. 14A and 14B are sectional views showing each step of a fine pattern forming method according to a sixth embodiment of the present invention. Is. As the chemically amplified resist, a resist containing an acid generator that generates an acid when irradiated with an energy beam and a compound that reacts with the acid, for example, SAL601 ER7 manufactured by Shipley Co., Ltd. is used.

First, as shown in FIG. 13A, a resist film 61 made of the chemically amplified resist is formed on a semiconductor substrate 60 made of silicon. Thereafter, the resist film 61 is exposed to a pattern of the mask 62 by irradiating a KrF excimer laser 63 as an energy beam using the mask 62. This way,
Acid is generated on the surface of the exposed portion 61a of the resist film 61.

Next, the exposed portion 61a of the resist film 61 is crosslinked by heating at 110 ° C. for 60 seconds to form a crosslinked portion 64 as shown in FIG. 13B.

Next, as shown in FIG. 13C, a silylation solution 65 is formed on the surface of the resist film 61 for 1 minute to form a silylation layer 66 on the non-exposed portion of the resist film 61. Rinse with xylene. Silylation solution 6
5 is 10% by weight of hexamethylcyclotrisilazane, 2% by weight of 1-methyl-2-pyrrolidone, 88w
It is a mixture with t% xylene.

Next, as shown in FIG. 14A, the semiconductor substrate 60 is heated to 110 ° C. and irradiated with deep ultraviolet rays 67 as a high energy beam for 60 seconds to remove the silylated layer 66 and the resist film 61. Increase the selection ratio of. conventionally,
Since the reaction between the silicon and the resist film was not sufficiently performed because the high energy beam was not irradiated to the silylated layer, the selectivity between the silylated layer and the resist film was not large. In the example, since the far-ultraviolet rays 67 are irradiated to the selectively formed silylated layer 66, volatilization of the carbon compound occurs due to oxidative decomposition of the carbon compound which is the resist composition, and silicon in the silylated layer 66 is vaporized. The concentration increases, and the etching selectivity between the silylated layer 66 and the resist film 61 increases.

Next, as shown in FIG. 14 (b), RI is performed using O ₂ plasma 68 with the silylated layer 66 as a mask.
By performing E, a resist pattern 69 is formed. In this case, the RIE conditions for the O ₂ plasma are as follows, using a parallel plate type RIE apparatus, power: 900 W, pressure:
0.7 Pa, flow rate: 40 SCCM.

[0094]

[Table 2]

[Table 2] shows the etching rates of the silylated layer and the non-silylated layer of the resist film and the etching selectivity in the case of the sixth embodiment and the conventional case. As shown in [Table 2], the etching selectivity was 6 in the case where the treatment with far ultraviolet light was not performed (conventional), while the case where the treatment with far ultraviolet light was performed (sixth embodiment).
Has an etching selectivity of 22.7, which is more than three times as high. When irradiation with far ultraviolet rays is not performed, the etching selectivity is low, so that there is a problem that the pattern shape is deteriorated and a pattern having a high aspect ratio is difficult to form. However, in the sixth embodiment, since the etching selectivity is improved by irradiating the silylated layer 66 with the far ultraviolet rays 65, a pattern having a high aspect ratio can be formed without falling down and without deteriorating the shape.

In the sixth embodiment, as the chemically amplified resist, SAL601 ER7 manufactured by Shipley Co., Ltd. was used, but instead of this, a compound having polyvinylphenol, novolac resin or the like as a compound which reacts with an acid is used. You may use.

As the silylation solution, a mixed solution of hexamethylcyclotrisilazane, 1-methyl-2-pyrrolidone and xylene was used, but bis (dimethylamino) dimethylsilane was used instead of hexamethylcyclotrisilazane. Other silylating agents may be used, such as propylene-glycol-methyl-ether-acetate instead of 1-methyl-2-pyrrolidone.

Although RIE using O ₂ plasma was used as the dry development method, ECR (electron cyclotron resonance etching) using O ₂ plasma or the like may be used instead of RIE.

Although the KrF excimer laser is used as the exposure light source, an ArF excimer laser or X-ray may be used instead of the KrF excimer laser.

(Seventh Embodiment) A fine pattern forming method according to a seventh embodiment of the present invention will be described below. The seventh embodiment relates to an acid generator that generates an acid when irradiated with an energy beam, and a polymer compound or a monomolecular compound in which at least a part of a phenolic hydroxyl group is substituted by a protecting group that is eliminated by the action of an acid. And a chemically amplified resist mainly composed of First, after the above chemically amplified resist was dropped on a semiconductor substrate, spin coating was performed so that a resist film having a film thickness of 1.0 μm was formed, and then a hot plate was used for 1 minute at a temperature of 90 ° C. Baking.

Specific examples of the polymer compound in which at least a part of the above-mentioned phenolic hydroxyl group is substituted with a protecting group that is eliminated by the action of an acid include, for example, poly (p-tert-
Butoxycarbonyloxystyrene), poly (p-tert-
Butoxystyrene), poly (p-tetrahydropyranyloxystyrene), poly (p- (1-ethoxyethoxy) styrene), poly (p- (1-methoxy-1-methylethoxy) styrene), poly (p-trimethylsilyl) Oxystyrene), poly (p-tert-butoxycarbonyloxystyrene-p-hydroxystyrene), poly (p-tert-butoxystyrene-p-hydroxystyrene), poly (p-tetrahydropyranyloxystyrene-p-hydroxystyrene) ), Poly (p- (1-ethoxyethoxy) styrene -p-
Hydroxystyrene), poly (p- (1-methoxy-1-)
Methylethoxy) styrene-p-hydroxystyrene),
Examples include, but are not limited to, poly (p-trimethylsilyloxystyrene-p-hydroxystyrene), poly (p-tert-butoxycarbonylmethoxystyrene-p-hydroxystyrene).

Specific examples of the monomolecular compound in which at least a part of the above-mentioned phenolic hydroxyl group is substituted with a protecting group which is eliminated by the action of an acid include, for example, 2,2-bis (4-tetrahydropyranyloxyphenyl). ) Propane, 2,2-bis (4-tert-butoxyphenyl) propane, 2,2-bis (4-t
ert-butoxycarbonyloxyphenyl) propane, 2,
2-bis (4- (1-ethoxyethoxy) phenyl) propane,
3,4-dihydro-4- (2,4-di- (1-tetrahydropyranyloxy) phenyl-7- (1-tetrahydropyranyloxy)-
2,2,4-trimethyl-2H-1-benzopyran, 3,4-dihydro-
4- (2,4-di- (1-tert-butoxy) phenyl-7- (1-tert-
Butoxy) -2,2,4-trimethyl-2H-1-benzopyran,
3,4-dihydro-4- (2,4-di- (1-ethoxyethoxy) phenyl-7- (1-ethoxyethoxy) -2,2,4-trimethyl-2
H-1-1-benzopyran and the like, but are not limited thereto.

The material composition of a typical chemically amplified resist is shown below.

(First Example of Resist Material) Poly (p-tert-butoxycarbonyloxystyrene-p-hydroxystyrene) (weight average molecular weight of about 9500, monomer unit ratio of about 1: 1) 6.0 g triphenylsulfonium hexafluoro Phosphate 0.3 g Diethylene glycol dimethyl ether 13.7 g (second example of resist material) Poly (p- (1-ethoxyethoxy) styrene-p-hydroxystyrene) (weight average molecular weight about 10,000, monomer unit ratio about 1: 1) 6.0 g 2-Cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane 0.3 g Diethylene glycol dimethyl ether 13.7 g (Third example of resist material) Poly p-vinylphenol (weight average molecular weight about 10,000) 5.0 g 2,2-bis (4 -Tetrahydropyranyloxyphenyl) propane 1.5 g 2- Clohexylcarbonyl-2- (p-toluenesulfonyl) propane 0.3 g Diethylene glycol diethyl ether 13.2 g (Fourth example of resist material) Poly (p-tert-butoxystyrene-p-hydroxystyrene) (weight average molecular weight about 10,000, Monomer unit ratio about 1: 1) 6.0 g bis-cyclohexylsulfonyldiazomethane 0.3 g diethylene glycol diethyl ether 13.7 g (fifth example of resist material) Poly p-vinylphenol (weight average molecular weight about 20,000) 5.0 g 3,4-dihydro -4- (2,4-di- (1-ethoxyethoxy) phenyl) -7- (1-ethoxyethoxy) -2,2,4-trimethyl-2H-1-benzopyran 1.5 g 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane 0.3 g methyl 3-methoxypropionate 13.2 g (Sixth example of resist material) Poly (p-tetrahydro Ranyloxystyrene-p-hydroxystyrene (weight average molecular weight about 10,000, monomer unit ratio about 3: 7) 6.0 g 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane 0.3 g 2-heptanone 13.7 g (resist material Seventh example) Poly (p- (1-methoxy-1-methylethoxy) styrene-p-hydroxystyrene) (weight average molecular weight: about 10,000, monomer unit ratio: about 1: 1) 6.0 g p-toluenesulfonic acid 2 1,6-dinitrobenzyl 0.1 g Diethylene glycol dimethyl ether 13.9 g (Eighth example of resist material) m-cresol novolak resin 5.0 g p-telolahydropyranyloxystyrene (weight average molecular weight about 10,000) 0.6 g triphenylsulfonium hexafluorophosphate 0.1 g diethylene glycol dimethyl ether 14.3 g After exposing the resist film with an excimer stepper having an optical wavelength of 248 nm and NA of 0.42, baking is performed for 1 minute at a temperature of 100 ° C. using a hot plate, and then development is performed for 1 minute with an organic alkali aqueous solution. Do.

Next, as a feature of the seventh embodiment, rinsing is performed with pure water containing 0.1 wt% of a surfactant such as polyoxyethylene propylene glycol.
As a result, even in a portion having a high aspect ratio, a large surface tension does not act between the resist patterns, so that the resist patterns do not lean. FIG. 15 (a)
Is a resist pattern 71A on a semiconductor substrate 70 formed by a conventional method similar to that of the seventh embodiment except for the rinsing liquid.
FIG. 15B shows the state of the resist pattern 71B on the semiconductor substrate 70 formed according to the seventh embodiment. As shown in FIG. 15A, in the resist pattern formed by the conventional method, a part of the pattern leans, whereas in contrast, FIG.
As shown in the figure, none of the resist patterns formed in the seventh embodiment leaned.

As the surface active agent, instead of polyoxyethylene propylene glycol ether, polyoxyethylene-P-nonylphenyl ether, polyoxyethylene cetyl ether, polyoxyethylene lauryl amine ether, or polyoxyethylene lauryl ammonium sulfate is used. The same effect can be obtained by using ether. Further, the concentration of the surfactant slightly varies depending on the type of the surfactant,
0.5 wt% is preferred.

Although the above-mentioned chemically amplified resists are all positive, the seventh embodiment is applicable even when a negative chemically amplified resist is used or when a normal positive or negative resist is used. The method for forming a fine pattern according to the above is effective.

[0108]

According to the method of forming a fine pattern according to the first aspect of the present invention, the carbon compound as a resist composition is oxidized and decomposed to volatilize the carbon compound and increase the density of the silylated layer. Since the etching selectivity between the oxide layer and the resist film is increased, a resist pattern having a high aspect ratio can be formed with high accuracy.

According to the fine pattern forming method of the second aspect of the present invention, since the surface tension of the rinse liquid acting between the fine resist patterns is reduced, the resist patterns do not get close to each other, so that a high aspect ratio is obtained. The resist pattern can be reliably formed.

According to the fine pattern forming method of the fifth aspect of the present invention, the action of desorbing the protective group by the acid is activated, so that the development of the exposed portion of the resist film is accelerated.

[Brief description of drawings]

FIGS. 1A to 1C are cross-sectional views showing each step of a fine pattern forming method according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating respective steps of a fine pattern forming method according to a first embodiment of the present invention.

FIG. 3A is a cross-sectional perspective view of a metal oxide film formed by the fine pattern forming method according to the first embodiment, and FIG. 3B is a cross-sectional view formed by the fine pattern forming method according to the first embodiment. FIG. 4 is a cross-sectional view of a resist pattern obtained.

FIGS. 4A to 4C are cross-sectional views illustrating respective steps of a fine pattern forming method according to a second embodiment of the present invention.

FIGS. 5A and 5B are cross-sectional views showing each step of a fine pattern forming method according to a second embodiment of the present invention.

FIGS. 6A and 6B are cross-sectional views showing steps of a fine pattern forming method according to a third embodiment of the present invention.

FIGS. 7A and 7B are cross-sectional views showing each step of a fine pattern forming method according to a third embodiment of the present invention.

FIGS. 8A to 8C are cross-sectional views showing steps of a fine pattern forming method according to a fourth embodiment of the present invention.

FIGS. 9A to 9C are cross-sectional views illustrating respective steps of a fine pattern forming method according to a fourth embodiment of the present invention.

FIGS. 10A to 10C are cross-sectional views showing steps of a fine pattern forming method according to a fifth embodiment of the present invention.

FIGS. 11A and 11B are cross-sectional views showing steps of a fine pattern forming method according to a fifth embodiment of the present invention.

FIGS. 12A and 12B are cross-sectional views showing steps of a fine pattern forming method according to a fifth embodiment of the present invention.

FIGS. 13A to 13C are cross-sectional views illustrating steps of a fine pattern forming method according to a sixth embodiment of the present invention.

FIGS. 14A and 14B are cross-sectional views showing steps of a fine pattern forming method according to a sixth embodiment of the present invention.

FIG. 15A is a sectional perspective view of a resist pattern formed by a conventional fine pattern forming method,
(B) is a sectional perspective view of a resist pattern formed by a fine pattern forming method according to a seventh embodiment of the present invention.

FIGS. 16A to 16C are cross-sectional views illustrating problems of the first conventional fine pattern forming method.

17 (a) and (b) are cross-sectional views showing respective steps of a second conventional fine pattern forming method.

FIGS. 18A and 18B are cross-sectional views showing each step of a second conventional fine pattern forming method.

FIG. 19 is a cross-sectional perspective view for explaining a problem of the second conventional fine pattern forming method.

[Explanation of symbols]

10 semiconductor substrate 11 resist film 11a exposed portion 12 mask 13 KrF excimer laser 14 steam 15 methyl steam 16 oxide film of triethoxysilane (MTEOS) 17 O ₂ plasma 18 resist pattern 20 semiconductor substrate 21 resist film 21a exposed portion 22 mask 23 KrF Excimer laser 24 Water vapor 25 MTEOS vapor 26 Oxide film 27 O ₂ plasma 28 Resist pattern 30 Semiconductor substrate 31 Resist film 31 a Exposure part 32 Mask 33 KrF excimer laser 34 Water vapor 35 Alkoxysilane solution 36 Oxide film 37 O ₂ plasma 38 Resist pattern 40 steam 47 oxide film of the semiconductor substrate 41 resist film 41a exposed portion 42 resin film 43 a mask 44 KrF excimer laser 45 steam 46 MTEOS 48 O _2-flop Zuma 49 resist pattern 50 semiconductor substrate 51 resist film 51a exposed portions 52 mask 53 KrF excimer laser 54 steam 55 MTEOS steam 56 oxide film 57 nitrogen gas 58 O ₂ plasma 59 resist pattern 60 semiconductor substrate 61 resist film 61a exposed portion 62 mask 63 KrF excimer laser 64 Crosslinking part 65 Silylation solution 66 Silylation layer 67 Far ultraviolet ray 68 O ₂ plasma 69 Resist pattern 70 Semiconductor substrate 71A, 71B Resist pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 21/30 569E (72) Inventor Masako Sasako 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Within

Claims (5)

[Claims] 1. A first step of forming a resist film on a semiconductor substrate by applying a resist containing a compound that crosslinks when irradiated with an energy beam, and irradiating the resist film with an energy beam to form the resist. A second step of crosslinking the exposed portion of the film; a third step of supplying a silylating agent to the surface of the resist film to form a silylated layer on the unexposed portion of the resist film; A fourth step of irradiating the layer with a high energy beam; and a fifth step of etching the resist film with the silylated layer irradiated with the high energy beam as a mask to form a resist pattern. A fine pattern forming method characterized by the following. 2. A first step of applying a resist film on a semiconductor substrate, a second step of pattern-exposing the resist film, and a resist pattern by developing the exposed resist film with a developing solution. And a fourth step of cleaning the developing solution and the resist material dissolved in the developing solution with a rinse solution containing a surfactant to remove the developing solution and the resist material dissolved in the developing solution. Fine pattern forming method. 3. The fine pattern forming method according to claim 2, wherein the surfactant contained in the rinse liquid in the fourth step is polyoxyethylene propylene glycol. 4. The resist film in the first step is
A chemically amplified resist comprising an acid generator that generates an acid when irradiated with an energy beam and a compound in which at least a part of the phenolic hydroxyl group is substituted with a protective group that is eliminated by the acid. Item 4. A fine pattern forming method according to Item 2 or 3. 5. The fine pattern forming method according to claim 4, further comprising a step of heating the exposed resist film between the second step and the third step.