JP2000206704A - Pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of patterning a lower layer film by which the film reduction of a resist pattern in the upper layer is suppressed and a pattern having sidewalls perpendicular to the film and a good square cross-sectional form can be formed with high resolution and high dimensional accuracy. SOLUTION: The method to form a pattern includes a process to form an org. silicon film 12 containing silicon and org. silicon compd having bonds with silicon in the main chain, on the film 11 to be processed, a process to form a resist pattern 13b on the org. silicon film 12, a process to selectively oxidize the exposed part of the org. silicon film 12 using the resist pattern 13b as a mask, and a process to dissolve and remove the oxidized part of the org. silicon film 12 in an atmosphere containing fluorine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a pattern used as an etching mask for finely processing a film to be processed and a pattern used as an interlayer insulating film.

[0002]

2. Description of the Related Art In a lithography process in a semiconductor device manufacturing process, photolithography using ultraviolet light as a light source is mainly used because of high throughput. In photolithography, in order to obtain a resist pattern with good dimensional control, an antireflection film is formed as a lower layer between the resist and an underlying substrate or the like to be processed, and the exposure light is reflected to the resist film. It is important to prevent. For example, as an antireflection film, a resin film that can be formed by a spin coating method is used because the process cost is low. In this case, the resist pattern is transferred to the resin film using the following method.

[0003] 1) Dry etching method 2) An anti-reflection film made of a resin film is formed using a photosensitive material such as polymethyl methacrylate or polysulfone, and the PCM method (Portable Comformab) is used.
However, since the component constituting the anti-reflection film as the lower layer film is made of an organic material of the same quality as the resist, the resist pattern can be accurately formed using a resin in any case. It was difficult to transfer to the film. For example, in the method 1),
Since the etching rates of the resist film and the resin film are substantially equal, the resist pattern retreats during the etching of the antireflection film, and in some cases, the resist pattern disappears during the etching. For this reason, it was difficult to etch the antireflection film with good dimensional controllability. This problem becomes more prominent when the limit of the photolithography approaches and the thickness of the resist film is reduced in order to improve the resolution. In the method 2), a mixing layer is formed between the conventional resin material and the resist film, which hinders the exposure step and the development step of the antireflection film. For this reason, it was difficult to transfer a resist pattern smaller than the sub-quarter micron to the antireflection film.

Further, a compound in which a dye is added to spin-on-glass has been disclosed (Jpn. J. Appl. Ph.
ys. 35 (1996), 1257), however, when the amount of the dye added is increased in order to provide sufficient antireflection ability, a problem arises in that the antireflection film is hardly abraded.

Further, JP-A-6-204130 describes the following pattern forming method. In this method, first, a resist pattern is formed on an antireflection film made of a silicon-based organic material, and the silicon-based organic material film is selectively glassed by performing an oxygen plasma treatment using the resist pattern as a mask. Thereafter, the glass portion of the silicon-based organic material is etched using the resist pattern as an etching mask. In this method, if oxygen plasma treatment is performed so that the resist pattern is not ashed and collapsed, the silicon-based organic material cannot be sufficiently oxidized, so that it is difficult to etch the resist pattern with a high selectivity to the resist pattern. there were.

In a semiconductor device, a wiring delay is caused by miniaturization of a wiring, which hinders high speed operation. In order to solve this problem, an attempt has recently been made to reduce the dielectric constant of the interlayer insulating film by using an organic silicon film as the interlayer insulating film. However, since the organic silicon film contains a carbon component in the film, various problems occur due to this. For example, when the organic silicon film is etched using the resist pattern as an etching mask, the selectivity with the resist pattern cannot be obtained, and the resist pattern may not be removed during the etching of the organic silicon film. Further, the resist pattern recedes, and it is difficult to process the organic silicon film with good dimensional control. In particular, this problem becomes remarkable when an attempt is made to improve the exposure margin by reducing the thickness of the resist when performing pattern exposure on the resist film.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method of patterning a lower layer film, which suppresses a reduction in the thickness of a resist pattern in the upper layer and has a good shape having vertical side walls and a rectangular cross section. It is an object of the present invention to provide a method for forming a fine pattern having high resolution and high dimensional accuracy.

Another object of the present invention is to provide a pattern forming method using an organic silicon film as an antireflection film which can be etched quickly on a resist pattern and can be formed by a spin coating method. .

Another object of the present invention is to provide a pattern forming method capable of improving the selectivity to resist when processing an organic silicon film using a resist pattern as an etching mask and processing the organic silicon film with good dimensional control. And

[0010]

According to a first aspect of the present invention, an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain is provided on a film to be processed. Forming, forming a resist pattern on the organic silicon film, selectively oxidizing an exposed portion of the organic silicon film using the resist pattern as a mask, and oxidizing the organic silicon film. Providing a pattern forming method including a step of dissolving and removing the removed portion in an atmosphere containing fluorine.

According to a second aspect of the present invention, there is provided a process for forming an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain on a film to be processed, wherein a resist pattern is formed on the organic silicon film. Forming, using the resist pattern as a mask, selectively oxidizing an exposed portion of the organic silicon film, and dissolving and removing the oxidized portion of the organic silicon film with an alkaline aqueous solution. Provided is a method for forming a pattern.

Further, a third invention is a method for forming an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain on a film to be processed, wherein a resist pattern is formed on the organic silicon film. Forming a,
Using the resist pattern as a mask, oxidizing the exposed portion of the organic silicon film by at least one of ultraviolet irradiation and heating, and dry-etching the oxidized portion of the organic silicon film using a fluorine-based gas. A pattern forming method comprising the step of removing by a method.

Still further, according to a fourth aspect of the present invention, there is provided a semiconductor device comprising:
Forming an organic silicon film containing an organic silicon compound having a bond between silicon and oxygen in a main chain, forming a resist pattern on the organic silicon film, using the resist pattern as a mask, Selectively decarbonizing the exposed portion of the organic silicon film by irradiating the exposed portion with ultraviolet light, and removing the decarbonized portion of the organic silicon film by dry etching using a fluorine-based gas. A method for forming a pattern is provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pattern forming method of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a process sectional view showing an example of the pattern forming method of the present invention.

First, as shown in FIG. 1A, an organic silicon film 12 is formed on a film 11 to be processed formed on a substrate. Examples of the processed film 11 include a silicon oxide film; a silicon nitride film; a silicon oxynitride film; spin-on glass; a silicon-based insulating film such as a blank material used in manufacturing a mask or the like; amorphous silicon, polysilicon, and silicon Silicon-based materials such as substrates; wiring materials and electrode materials such as aluminum, aluminum silicide, copper, tungsten, tungsten silicide, cobalt silicide, and ruthenium, but are not limited thereto.

When the development process of the organic silicon film is performed in an atmosphere containing fluorine, the film to be processed may be etched by fluorine when a high concentration of a developing solution is used. Such a phenomenon may also be caused by a combination of the material of the film to be processed and the developer. To avoid this, it is preferable to form a thin film which is resistant to fluorine and acts as an etching stopper film on the film to be processed before forming the organic silicon film on the film to be processed. The thin film preferably has a thickness of 0.005 to 0.5 μm.
If the thickness is less than 0.005 μm, there is a possibility that fluorine may permeate the thin film and etch the film to be processed. 0.5
When the thickness exceeds μm, a dimensional conversion difference occurs when processing a thin film, and it becomes difficult to process a film to be processed with good dimensional controllability. As such a thin film, for example, a positive resist containing o-quinonediazide and a novolak resin, polystyrene, polymethyl methacrylate, polyvinylphenol novolak resin, polyester, polyvinyl alcohol, polypropylene, polybutadiene, polyvinyl acetate and polyvinyl butyral imide, etc. A resin film may be used.

The organic silicon film 12 contains an organic silicon compound having a bond between silicon and silicon in its main chain, and the Si—Si bond forming the main chain of this compound absorbs ultraviolet light. Therefore, when pattern exposure is performed on the resist film formed on the organic silicon film 12 using ultraviolet light, the organic silicon film 12 prevents reflection of the exposure light to the resist film, so that the anti-reflection film is formed. Act as In addition, the organic silicon film 12 according to the present invention has an electric resistance that is reduced by adding a conductive substance or a substance that becomes conductive by light or heat, so that the organic silicon film 12 can also function as an antistatic film. it can.

The thickness of the organic silicon film 12 is 0.005.
It is preferably about 5 μm. The reason is that when the film thickness is less than 0.005 μm, when forming a pattern by light exposure, the reflected light from the underlying substrate cannot be sufficiently suppressed. This is because there is a possibility that a dimensional conversion difference is remarkably generated when transferring to the organic silicon film by the method described above.

In the method of the present invention, the organic silicon film 12
Can be formed on the film to be processed 11 by a method of applying a solution or by a gas phase method such as a CVD method (chemical vapor deposition method), but an organic silicon film is formed by a coating method. Is preferred. This is because the coating method has a simpler process cost than the CVD method. Here, a method of forming an organic silicon film by a coating method will be described in detail.

First, an organic silicon compound having a bond between silicon and silicon in its main chain is dissolved in a predetermined organic solvent to prepare a solution material. Examples of the organosilicon compound that can be used in the present invention include polysilane having a repeating unit represented by the following general formula (1).

[0022]

Embedded image

(In the general formula (1), R ¹ and R ² may be the same or different and each represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms,
An alicyclic hydrocarbon group or an aromatic hydrocarbon group; The repeating unit may have a structure in which two or more kinds are bonded to each other via an oxygen atom, a nitrogen atom, an aliphatic group, an aromatic group, or the like. Examples of the organosilicon compound that can be used are shown in the following chemical formulas [1-1] to [1-118]. In the formula, m and n represent positive integers.

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

The weight average molecular weight of such a compound is not particularly limited, but is preferably from 200 to 100,000. The reason is that if the molecular weight is less than 200, the organic silicon film is dissolved in the resist solvent, while
If it exceeds 000, it is difficult to dissolve in an organic solvent, and it is difficult to prepare a solution material. The organic silicon compound is not limited to one kind, and may be used by mixing several kinds of compounds.

For the organosilicon compound, if necessary, a thermal polymerization inhibitor for improving storage stability, an adhesion enhancer for improving adhesion to a film to be processed, and a resist for improving the adhesion to a film to be processed. Use a dye that absorbs ultraviolet light to prevent light reflected into the film, a polymer that absorbs ultraviolet light such as polysulfone, polybenzimidazole, a conductive substance, a substance that becomes conductive by light or heat, or an organic silicon compound. A crosslinking agent capable of crosslinking may be added.

Examples of the conductive substance include organic sulfonic acids, organic carboxylic acids, polyhydric alcohols, polyhydric thiols (for example, iodine and bromine), SbF ₅ , PF ₅ , BF
₅ , SnF _{5 and the} like. Examples of a substance which becomes conductive by application of energy such as light or heat include carbon clusters (C ₆₀ , C ₇₀ ), cyanoanthracene, dicyanoanthracene, triphenylpyrium, tetrafluoroborate, tetracyanoquinodimethane, and tetracyanoquinodimethane. Examples include cyanoethylene, phthalimide triflate, perchloropentacyclododecane, dicyanobenzene, benzonitrile, trichloromethyltriazine, benzoyl peroxide, benzophenonetetracarboxylic acid, and t-butyl peroxide. More specifically,
Compounds represented by the following formulas [2-1] to [2-106] can be mentioned.

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

When a crosslinking agent is added, the organosilicon compound is preferably one in which hydrogen is bonded to silicon in the main chain. Examples of such an organosilicon compound include the structures described in the aforementioned chemical formulas [1-1] to [1-26].

The crosslinking agent is added to crosslink the organosilicon compound to prevent mixing of the resist and the organosilicon compound and to improve heat resistance.

As the cross-linking agent, a compound having a multiple bond can be used. The organic substance having a multiple bond is
A compound having a double bond or a triple bond, more specifically, a compound having a vinyl group, an acrylic group, an aryl group, an imide group, an acetylenyl group, or the like. The organic substance having such a multiple bond may be any of a monomer, an oligomer, and a polymer.

The organic substance having such a multiple bond causes an addition reaction with the Si—H bond of the organic silicon compound by heat or light to crosslink the organic silicon compound. Note that the organic substance having a multiple bond may be self-polymerized. Specific examples of the organic substance having a multiple bond are shown below.

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

[0063]

Embedded image

[0064]

Embedded image

[0065]

Embedded image

[0066]

Embedded image

As described above, when an organic substance having a multiple bond is mixed with an organic silicon compound, a radical generator or an acid generator may be added as a catalyst. These radical generators are composed of an organic substance having a multiple bond and Si.
It serves to assist the addition reaction with -H or self-polymerization.

Examples of the radical generator include azo compounds (eg, azobisisobutyronitrile), peroxides, alkylaryl ketones, silyl peroxides, and organic halides. The radical generator generates a radical by decomposing an O—O bond or a C—C bond in a molecule by light irradiation or heating. Examples of the radical generator include those represented by compounds [4-1] to [4-11] and chemical formulas [4-12] to [4-24].

Benzoyl peroxide [4-1] di-tert-butyl peroxide [4-2] benzoin [4-3] benzoin alkyl ether [4-4] benzoin alkylaryl thioether [4-5] benzoyl aryl ether [4-6] Benzylalkylarylthioether [4-7] Benzylaralkylethanol [4-8] Phenylglyoxalalkylacetal [4-9] Benzoyloxime [4-10] Triphenyl-t-butylsilyl peroxide [4-11]

[0070]

Embedded image

[0071]

Embedded image

Of the radical generators, organic halides
Represents a trihalomethi represented by the general formula [4-18]
Ru-s-triazine (e.g. U.S. Pat. No. 3,779,778)
Is preferred. General formula [4-18]
Q is bromine or chlorine, R ¹¹Is -CQ_Three, -NH_Two,
-NHR¹³, -OR¹³Or substituted or unsubstituted
Nyl group, R¹²Is -CQ_Three, -NH_Two, -NHR¹³, -N
(R¹³)_Two, -OR¹³,-(CH = CH)_n-W or
A substituted or unsubstituted phenyl group, wherein R¹³Is
Phenyl, naphthyl or lower alkyl having 6 or less carbon atoms
A group, n is an integer of 1 to 3, W is an aromatic ring, a heterocyclic ring, or
It is a group represented by the following general formula. ). these
May, in some cases, present compounds with multiple bonds.
Crosslink polysilanes by light or heat
Sometimes.

[0073]

Embedded image

In the formula, Z represents oxygen or sulfur, and R ¹⁰ represents a lower alkyl group or a phenyl group.

Among the trihalomethyl-s-triazines represented by the general formula [4-18], particularly, when R ¹² is-(C
Vinyltrihalomethyl-s-triazines (H = CH) _n -W (see, for example, US Pat. No. 3,987,037) are preferred. Vinyl trihalomethyl-s-triazine is a photohalable s-triazine having a trihalomethyl group and an ethylenically unsaturated bond conjugated to a triazine ring.

The following substituents may be introduced into the aromatic or heterocyclic ring represented by W. Examples include chlorine, bromine, phenyl, lower alkyl having 6 or less carbon atoms, nitro, phenoxy, alkoxy, acetoxy, acetyl, amino, and aminoalkyl groups.

The trihalomethyl-s-triazine represented by the general formula [4-18] is converted from the chemical formulas [4-25] to [4-
34], other radical generators represented by the chemical formula [4-3]
5] to [4-39]. These halides are
In some cases, the polysilane may be cross-linked by light or heat without the presence of a compound having a multiple bond.

[0078]

Embedded image

[0079]

Embedded image

Examples of the acid generator include onium salts, halogen-containing compounds, orthoquinonediazide compounds, sulfone compounds, sulfonic acid compounds, and nitrobenzyl compounds. Of these, onium salts and orthoquinonediazide compounds are preferred.

Examples of the onium salts include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, and ammonium salts. Preferably, the chemical formula [4-4]
0] to [4-42].

Examples of the halogen-containing compound include a haloalkyl group-containing hydrocarbon compound, a haloalkyl group-containing hydrocarbon compound, and a haloalkyl group-containing heterocyclic compound. In particular, the chemical formulas [4-43] and [4-
44] is preferred.

Examples of the orthoquinonediazide compound include a diazobenzoquinone compound and a diazonaphthoquinone compound. In particular, the chemical formulas [4-45] to [4-4]
8] is preferred.

Examples of the sulfone compound include β-ketosulfone and β-sulfonylsulfone. In particular,
The compound represented by the chemical formula [4-49] is preferable.

Examples of the nitrobenzyl compound include a nitrobenzylsulfonate compound and a dinitrobenzylsulfonate compound. In particular, the chemical formula [4-5]
0] are preferred.

Examples of the sulfonic acid compound include alkyl sulfonic acid esters, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates. In particular, the chemical formulas [4-51] to [4-53]
The compound represented by is preferred.

[0087]

Embedded image

(In the formula, R ^{14 to} R ¹⁶ may be the same or different, and each represents a hydrogen atom, an amino group,
A nitro group, a cyano group, a substituted or unsubstituted alkyl group or an alkoxyl group, and X represents SbF ₆ , PF ₆ , B
F ₄ , CF ₃ CO ₂ , ClO ₄ , CF ₃ SO ₃ ,

[0089]

Embedded image

R ¹⁷ is a hydrogen atom, an amino group, an anilino group,
A substituted or unsubstituted alkyl group or an alkoxyl group, R ¹⁸ and R ¹⁹ may be the same or different from each other, and each is a substituted or unsubstituted alkoxyl group;
R ²⁰ represents a hydrogen atom, an amino group, an anilino group, a substituted or unsubstituted alkyl group or an alkoxyl group.

[0091]

Embedded image

(In the formula, R ²¹ represents a trichloromethyl group, a phenyl group, a methoxyphenyl group, a naphthyl group or a methoxynaphthyl group.)

[0093]

Embedded image

(In the formula, R ^{22 to} R ²⁴ may be the same or different and each represents a hydrogen atom, a halogen atom, a methyl group, a methoxy group or a hydroxyl group.)

[0095]

Embedded image

(Wherein R ²⁵ represents —CH ₂ —, —C (CH
_{3) 2 -, - C (} = O) - or -SO ₂ - indicates, q
Is an integer of 1 to 6, r is an integer of 0 to 5, and the sum of q and r is 1 to 6. )

[0097]

Embedded image

(Wherein, R ²⁶ is a hydrogen atom or a methyl group, R ²⁷ is —CH ₂ —, —C (CH ₃ ) ₂ —, —C
(= O) - or -SO ₂ - indicates, s is an integer from 1 to 6, t is an integer from 0 to 5, the sum of s and t is 1 to 6
It is. )

[0099]

Embedded image

(Wherein, R ^{28 to} R ³¹ may be the same or different from each other, and each represents a substituted or unsubstituted alkyl group or a halogen atom, and Y represents —C (（O) —
Or -SO _2- , and u is an integer of 0 to 3. )

[0101]

Embedded image

Wherein R ³² is a substituted or unsubstituted alkyl group, R ³³ is a hydrogen atom or a methyl group, and R ³⁴ is

[0103]

Embedded image

(Provided that R ³⁵ is a hydrogen atom or a methyl group, R ³⁶ and R ³⁷ may be the same or different, and each represents a substituted or unsubstituted alkoxyl group; Is an integer.)

[0105]

Embedded image

(In the formula, R ³⁸ and R ³⁹ may be the same or different, and a hydrogen atom or a substituted or unsubstituted alkyl group, R ⁴⁰ and R ⁴¹ may be the same or different. And each represents a hydrogen atom or a substituted or unsubstituted alkyl group or aryl group.)

[0107]

Embedded image

(In the formula, R ⁴² is a hydrogen atom or a substituted or unsubstituted alkyl group, R ⁴³ and R ⁴⁴ may be the same or different, and each represents a substituted or unsubstituted alkyl group or an aryl group. And R ⁴³ and R ⁴⁴ may combine with each other to form a ring structure.)

[0109]

Embedded image

(In the formula, Z represents a fluorine atom or a chlorine atom.) In the present invention, as a cross-linking agent for the organosilicon compound, the following substances other than the above-mentioned organic substance having a multiple bond may be used. it can. For example, an organic substance having a hydroxyl group, an organic substance having an epoxy group, an organic substance having an amino group, pyridine oxide, an alkoxysilyl group, a silyl ester group, an oximusilyl group, an ethoxysilyl group, an aminosilyl group, an amidosilyl group, an aminoxysilyl group, or Examples thereof include a silicon compound having a halogen, an organic metal compound, and a compound including a halogen.

Examples of the compound having a hydroxyl group include:
Examples include polyhydric alcohols, novolak resins, compounds having a carboxyl group, and silanols. These compounds react with Si—H by light or heat to crosslink the organosilicon compound. Specific examples of such compounds are shown in chemical formulas [5-1] to [5-28].

Examples of the compound having an epoxy group include those generally called epibis type epoxy resins or alicyclic epoxy resins. In these resins, a hydroxyl group may be partially added. Further, the above-mentioned acid generator may be added together with these resins. A specific example of such a compound is represented by a chemical formula [6-1].
To [6-12].

Examples of the compound having an amino group include those described in [7-1] to [7-13].

Examples of the pyridine oxide include those represented by the chemical formulas [8-1] to [8-6].

An alkoxysilyl group, a silyl ester group,
Examples of the silicon compound having an oximesilyl group, an ethoxysilyl group, an aminosilyl group, an amidosilyl group, an aminoxysilyl group, or a halogen include a compound represented by the chemical formula [9-
1] to [9-52]. In these chemical formulas, X represents the above substituent. In addition, together with these compounds, platinum usually used as a condensation catalyst for silicone, metal catalysts such as organotin compounds,
A base may be used.

The organic metal compound means a metal salt or metal complex substituted by an organic group. B, Mg,
Al, Ca, Ti, V, Mn, Fe, Co, Ni, C
u, Zn, Zr, Mo, Rh, Pd, Cd, In, Sn
Is used. Specific examples of such compounds are shown in chemical formulas [10-1] to [10-8].

Examples of the compound containing a halogen include those represented by the chemical formulas [11-1] to [11-9].

[0118]

Embedded image

[0119]

Embedded image

[0120]

Embedded image

[0121]

Embedded image

[0122]

Embedded image

[0123]

Embedded image

[0124]

Embedded image

[0125]

Embedded image

[0126]

Embedded image

[0127]

Embedded image

[0128]

Embedded image

[0129]

Embedded image

[0130]

Embedded image

The organic solvent for dissolving the organic silicon compound is not particularly limited. For example, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methyl cellosolve,
Cellosolve solvents such as methyl cellosolve acetate, ethyl cellosolve acetate, ethyl lactate, ethyl acetate,
Examples thereof include ester solvents such as butyl acetate and isoamyl acetate, alcohol solvents such as methanol, ethanol, and isopropanol, and anisole, toluene, xylene, and naphtha.

As described above, a coating material as a raw material of an organic silicon film is prepared by dissolving a predetermined organic silicon compound and, if necessary, another compound in an organic solvent. The obtained coating material is applied on the film to be processed 11 by, for example, a spin coating method, a dipping method or the like.
The organic silicon film 12 can be formed by heating or crosslinking at 500 ° C. for about 10 seconds to 60 minutes. When the organic silicon compound is oxidized by heating, it is preferable to heat the organic silicon compound in an atmosphere of an inert gas such as a low oxygen concentration N ₂ , Ar, or He. In this case, the oxygen concentration is preferably 1% or less, more preferably 50 ppm or less.

Next, a resist pattern is formed on the organic silicon film 12. In forming a resist pattern, first, as shown in FIG.
2, a resist film 13 is formed. When the thickness of the resist film 13 is reduced, the exposure latitude, the focus latitude, and the resolution can be improved. Therefore, the thickness of the resist film 13 is preferably as small as possible so long as the organic silicon film 12 can be etched with good dimensional controllability, and is preferably 0.01 to 10 μm.

The resist composition for forming the resist film 13 is not particularly limited as long as it is a composition that can be patterned by exposure to visible light, ultraviolet light, or the like, and a positive type or a negative type is selected and used. be able to. As the positive resist composition, for example, a resist composition containing naphthoquinonediazide and a novolak resin (I)
X-770, manufactured by JSR), a chemically amplified resist composition containing a polyvinylphenol resin protected with t-BOC and an acid generator (APEX-E, manufactured by Shipley),
And a resist composition (UVIIHS, manufactured by Shipley) containing a polyvinyl phenol resin obtained by copolymerizing tertiary butyl methacrylate and an acid generator. Examples of the negative resist include a chemically amplified resist (SNR200, manufactured by Shipley) containing polyvinylphenol, a melamine resin, and a photoacid generator, and a resist (RD) containing polyvinylphenol and a bisazide compound. -2000N, manufactured by Hitachi Chemical Co., Ltd.), but is not limited thereto.

The solution of the resist composition as described above was
After coating on the organic silicon film 12 by a method such as a spin coating method or a dipping method, the solvent is vaporized by heating at 50 to 180 ° C. for about 10 seconds to 5 minutes using a hot plate, an oven, or the like, thereby forming a resist. A film 13 is formed. An upper anti-reflection layer for reducing multiple reflections generated in the resist film when light exposure is performed, or an upper anti-static film for preventing charge-up generated when electron beam exposure is performed is formed of a resist film. 13 may be formed as needed.

The resist film 13 thus formed is subjected to pattern exposure as shown in FIG. That is, the resist film 13 is irradiated with the exposure light 14 via a mask having a desired pattern. As the exposure light 14, visible light, ultraviolet light, or the like can be preferably used.
As a light source for irradiating ultraviolet light, for example, a mercury lamp,
XeF (wavelength = 351 nm), XeCl (wavelength = 308)
nm), KrF (wavelength = 248 nm), KrCl (wavelength = 222 nm), ArF (wavelength = 193 nm), and excimer lasers such as F ₂ (wavelength = 151 nm). Further, pattern exposure may be performed using an electron beam, an ion beam, or X-rays.

By such pattern exposure, a latent image is formed on the exposed portion of the resist film 13.

After the latent image is formed, the resist film 13 is developed with a predetermined developing solution to dissolve and remove the latent image portion of the resist film, thereby forming a resist pattern as shown in FIG. You. The developer used here can be appropriately selected according to the resist material. For example, an alkali developing solution such as a tetramethylammonium hydroxide solution, choline, sodium hydroxide, potassium hydroxide and the like can be mentioned.

Here, since an example using a positive type resist is described, a resist pattern is formed by an unexposed portion 13b remaining after the exposed portion 13a of the resist film 13 is dissolved and removed. When the resist is used, the unexposed portion 13b of the resist film 13 is dissolved and removed to form a resist pattern by the cross-linked exposed portion 13a.

Using the obtained resist pattern as a mask, an oxygen source 15 was supplied as shown in FIG.
An exposed portion (a portion not covered with the resist pattern) of the organic silicon film 12 is selectively oxidized. As the oxidation treatment method that can be adopted here, the following method can be mentioned. (I) The entire surface of the wafer is irradiated with an energy beam such as an electron beam, an ion beam, ultraviolet light, and X-rays. In particular, when the resist contains an aromatic resin such as a phenolic resin, it is preferable to irradiate ultraviolet light in a wavelength region of 150 to 230 nm or less. This is because the aromatic resin contained in the resist has high absorptivity to ultraviolet light in these wavelength regions, so that the region not covered by the resist pattern has a high contrast with the covered region. This is because it becomes possible to irradiate light. In the case of a resist containing an alicyclic resin as a main component, 150
It is preferable to irradiate ultraviolet light in a wavelength region of 180 nm. Such a resist has a high absorbency against ultraviolet light in this wavelength region, and therefore, it is possible to irradiate a region not covered with the resist pattern with a high contrast to the region covered with the resist pattern. It is.

The irradiation amount of the ultraviolet light irradiation is 0.01 to 10;
It is preferably 000 J / cm ² . 0.01J /
If it is less than ² cm ^2, it is difficult to sufficiently oxidize the exposed portion of the organic silicon film, while 10,000 J /
If it exceeds cm ² , oxidation proceeds even in the portion covered with the resist pattern, and it becomes difficult to process the organic silicon film with good anisotropy.

The irradiation amount of the electron beam is 0.01 m
It is preferably ^{C / cm 2 ~1,000C / cm 2} . If it is less than 0.01 mC / cm ² , it becomes difficult to sufficiently oxidize the exposed portion of the organic silicon film, while if it exceeds 1,000 C / cm ² , oxidation will occur even in the portion covered with the resist pattern. As the process proceeds, it may be difficult to process the organic silicon film with good anisotropy.

By irradiating the energy beam as described above, the Si—Si bond of the main chain in the organic silicon compound or the bond between silicon of the main chain and the side chain in the exposed portion of the organic silicon film 12 is cleaved. As a result, dangling bonds of silicon occur. Oxygen is bonded to this dangling bond, and an oxidation reaction proceeds. On the other hand, in the portion of the organic silicon film 12 which is covered with the resist pattern 13b, since the irradiation intensity of the energy beam is lower than that of the exposed portion, the above-described bond is hard to be broken and is not oxidized. (II) The entire surface of the wafer is irradiated with oxygen radicals obtained by discharging oxygen plasma. Specifically, using a down-flow plasma apparatus, source gas O ₂ = 10
10,000 SCCM, excitation power 100 to 10,000
Oxygen plasma is generated under the conditions of 0 W and a degree of vacuum of 1 to 10,000 mTorr, and the entire surface of the wafer is irradiated.

By irradiating oxygen radicals under these conditions, in the exposed portion of the organic silicon film 12, oxygen radicals are bonded to the main chain Si—Si bond or the main chain silicon and the side chain in the organic silicon compound. Is cleaved, and the dangling bond of silicon and the oxygen radical combine to cause an oxidation reaction to proceed. On the other hand, the organic silicon film 1
In the portion covered by the second resist pattern 13b, oxidation does not occur because the resist pattern acts as a mask and oxygen radicals do not penetrate. (III) Exposing the wafer to an ozone atmosphere. In this case, it is desired that the ozone in the atmosphere is at least 50 ppb or more. If it is less than 50 ppb, it becomes difficult to sufficiently oxidize the exposed portion of the organic silicon film 12.

At the exposed portion of the organic silicon film 12, the ozone cleaves the Si—Si bond of the main chain in the organic silicon compound or the bond between silicon and the side chain of the main chain, and bonds with the dangling bond of silicon. The oxidation reaction proceeds. On the other hand, the portion of the organic silicon film 12 covered with the resist pattern does not permeate ozone and does not oxidize.

By performing such an oxidation treatment, Si—O—Si bonds are selectively formed in the main chain of the organic silicon compound contained in the exposed portion of the organic silicon film 12. Further, when a hydrogen atom is bonded to silicon in the main chain of the organic silicon compound, Si—O
H is formed.

When the organic silicon film 12 is oxidized by any of the above-described methods, the composition ratio of silicon, oxygen, and carbon in the exposed portion 12a of the organic silicon film 12 must be within a predetermined range. preferable. Specifically, assuming that the numbers of silicon, oxygen, and carbon atoms contained in the organic silicon film are p, q, and r, respectively, q /
It is preferable to oxidize so as to satisfy the relationship of p ≧ 0.1 and r / p ≦ 0.8. q / p <0.1 or r / p
> 0.8, when the organic silicon film 12 is etched using the resist pattern 13b as an etching mask, the fluorocarbon polymer film is
The organic silicon film is deposited on the surface and becomes difficult to be etched, and the selectivity with respect to the resist decreases. as a result,
During the etching of the organic silicon film 12, the resist pattern 13b is not completely removed or receded, so that it becomes difficult to process the organic silicon film 12 with good dimensional control.

Next, the organic silicon film 12 is removed with a predetermined developing solution.
By selectively removing the oxidized portion, an organic silicon film pattern as shown in FIG. 1 (f) is formed.

As the developing solution, a solution containing fluorine can be used, and specific examples include a solution obtained by diluting hydrogen fluoride or ammonium fluoride with pure water. In this case, it is preferable to dilute with 1 to 1,000,000 volumes of pure water per 1 volume of hydrogen fluoride or ammonium fluoride. If the volume of pure water is less than 1 volume, unoxidized portions of the resist pattern and the organic silicon film may be altered by fluorine atoms, while if it exceeds 1,000,000 volumes, the oxidized portion of the organic silicon film is dissolved and removed. It will be difficult to do.

Further, a mixture of hydrogen fluoride and ammonium fluoride may be used, and the mixing ratio is preferably in the range of 1 <(ammonium fluoride / hydrogen fluoride) <100. In the case of mixing, the dilution ratio of pure water is preferably 1 to 1,000,000 volumes of pure water with respect to 1 volume of the total volume of ammonium fluoride and hydrogen fluoride. If the volume of pure water is less than 1 volume, unoxidized portions of the resist pattern and the organic silicon film may be altered by fluorine atoms, while if it exceeds 1,000,000 volumes, the oxidized portion of the organic silicon film is dissolved and removed. It will be difficult to do. By mixing hydrogen fluoride and ammonium fluoride in this way, high reproducibility of the etching rate can be obtained without swelling the resist pattern.

The method of supplying the solution is not particularly limited, and examples thereof include a method of dipping the wafer into the solution, a method of spraying the solution onto the wafer by spraying, and a method of pouring the solution onto the wafer. Can be In the case where the oxidized portion of the organic silicon film is dissolved and removed using a solution containing fluorine, the oxidized portion may be dissolved and removed using the above-described vapor containing a fluorine atom.

In the pattern forming method of the present invention, a lower layer film is formed between a film to be processed and a resist film using a material containing a specific organic silicon compound, and a predetermined pattern of the organic silicon film is formed using the resist pattern as a mask. Region is selectively oxidized. Since the oxidized portion of the organic silicon film can be dissolved and removed with a specific developer, it is possible to form an organic silicon film pattern by transferring a fine resist pattern to the organic silicon film with high dimensional accuracy. . Specifically, it is defined by the difference (YX) between the dimension (X) of the resist pattern shown in FIG. 1D and the dimension (Y) of the organic silicon film pattern shown in FIG. Dimensional conversion difference can be suppressed to 10 nm or less.

In addition, in the process of oxidizing the organic silicon film and the process of dissolving and removing the oxidized portion, no reduction in the thickness of the resist pattern occurs, so that the resolution can be increased by reducing the resist film thickness. .

The mask material pattern composed of the resist pattern and the organic silicon film pattern thus formed has a good cross-sectional shape and a sufficient film thickness. Can be effectively used as an etching mask.

Next, the pattern forming method of the second invention will be described.

In the pattern forming method of the second invention, the oxidized portion of the organic silicon film 12 as described above is dissolved and removed with an alkaline aqueous solution. In this case, the organic silicon compound contained in the organic silicon film 12 needs to have a hydrogen atom bonded to silicon in the main chain. Such organic silicon compounds include, for example, the structures represented by the aforementioned chemical formulas [1-1] to [1-26]. The second pattern forming method can be performed in the same manner as the above-described pattern forming method of the first invention, except that the organic silicon compound and the developing solution for developing the organic silicon film are changed.

The reason why the oxidized portion of the organic silicon film can be dissolved and removed with an aqueous alkaline solution is that the hydrogen atoms in the side chains become hydroxyl groups and become soluble in the aqueous alkaline solution as described above. In addition, even if the organic silicon film has a Si-OH unit in advance, regardless of the oxidation treatment, it is possible to selectively dissolve and remove only the oxidized portion with an alkaline aqueous solution. The reason for this is that the oxidation treatment generates a Si—O—Si bond, improves the polarity, and facilitates the penetration of an alkaline aqueous solution. Si-OH
Examples of the organosilicon compound having a unit include the structures represented by the aforementioned chemical formulas [1-115] to [1-118].

Examples of the aqueous alkali solution that can be used in the second pattern forming method include, for example, an aqueous organic alkali solution such as tetramethylammonium hydroxide and choline;
An aqueous solution of an inorganic alkali such as sodium hydroxide or potassium hydroxide can be used. In this case, the normality of the aqueous alkali solution is preferably 0.01 to 1.0 normal. 0.
If it is less than 01 normal, it is difficult to dissolve and remove the oxidized portion of the organic silicon film 12, while if it exceeds 1.0 normal, the resist pattern may be attacked by an aqueous alkaline solution.

The organic silicon film 12 is formed with an aqueous alkali solution.
In the second invention in which the oxidized portion is dissolved and removed,
Similarly to the pattern forming method of the first invention, it is possible to transfer a fine resist pattern onto an organic silicon film with high dimensional accuracy and form an organic silicon film pattern with a dimensional conversion difference of 10 nm or less. In addition, during the oxidation treatment of the organic silicon film and the dissolution removal treatment of the oxidized portion,
Since there is no reduction in the film thickness of the resist pattern, the resolution can be increased by reducing the resist film thickness.

The mask material pattern formed by the thus formed resist pattern and organic silicon film pattern has a good cross-sectional shape and a sufficient film thickness. Can be effectively used as an etching mask.

Next, the pattern forming method of the third invention will be described.

FIGS. 2 and 3 are process sectional views showing an example of the pattern forming method of the third invention.

First, as shown in FIG. 2A, an organic silicon film 116 is formed on a film 115 to be processed provided on a silicon wafer 110. Examples of the film to be processed include a silicon oxide film; a silicon nitride film; a silicon oxynitride film; spin-on-glass; a silicon-based insulating film such as a blank material used in manufacturing a mask or the like; amorphous silicon, polysilicon, and a silicon substrate. And silicon-based materials such as aluminum, aluminum silicide, copper, tungsten, tungsten silicide, cobalt silicide, ruthenium, and other wiring materials and electrode materials, but are not limited thereto.

In the example shown in FIG. 2A, the processed film 115 is formed on the silicon wafer 110 via the silicon oxide film 111, and the processed film 115 is
12, Ti layer 113 and 0.5% Cu-Al layer 114
Is a metal wiring layer having a laminated structure including:

The organic silicon film 116 contains an organic silicon compound having a bond between silicon and silicon in its main chain, and the Si—Si bond forming the main chain of this compound absorbs ultraviolet light. Therefore, the organic silicon film 11
When pattern exposure is performed on the resist film formed on the substrate 6 using ultraviolet light, the organic silicon film 116 is exposed.
Acts as an anti-reflection film because it prevents exposure light from reflecting on the resist film.

The thickness of the organic silicon film 116 is 0.00
It is preferably about 5 to 5 μm. Thickness 0.00
If it is less than 5 μm, when performing pattern formation by light exposure,
If the reflected light from the base substrate cannot be sufficiently suppressed, while if the thickness exceeds 5 μm, a significant dimensional conversion difference occurs when the resist pattern is transferred to the lower layer film by the third method of the present invention. This is because there is a risk of doing so.

In the third method of the present invention, the organic silicon film 116 is formed by applying a solution or
Although a film can be formed on a film to be processed by a vapor phase method such as a VD method (chemical vapor deposition method), it is preferable to form an organic silicon film by a coating method. This is because the coating method has a simpler process cost than the CVD method.

That is, in the third pattern forming method of the present invention, as in the case of the above-mentioned first pattern forming method, a coating method using a polysilane having a repeating unit represented by the general formula (1) is used. Thus, an organic silicon film can be formed. As the organosilicon compounds that can be used, in addition to the compounds represented by the aforementioned general formulas [1-1] to [1-118], the following general formulas [1-119] to [1-119]
120]. In the equation,
m and n represent positive integers.

[0169]

Embedded image

The weight average molecular weight of such a compound is not particularly limited, but may be 200 to 10 for the same reason as described above.
Preferably it is 000.

For the organosilicon compound, if necessary, a thermal polymerization inhibitor for measuring storage stability, an adhesion improver for improving adhesion to a film to be processed, and a resist for improving the adhesion to a film to be processed. A dye that absorbs ultraviolet light to prevent light from being reflected into the film, a polymer that absorbs ultraviolet light such as polysulfone, polybenzimidazole, a conductive substance, a substance that becomes conductive by light or heat, or an organic silicon compound A crosslinking agent capable of crosslinking may be added.

Examples of such compounds include those already described in the first pattern forming method.

Also in the third pattern forming method, a coating material as a raw material of an organic silicon film is prepared by dissolving a predetermined organic silicon compound and, if necessary, another compound in an organic solvent. The organic silicon film 116 is formed by applying the film on the processing film 115 and heating. The organic solvent that can be used here, the heating conditions, and the like are the same as in the case of the first pattern forming method.

In the third pattern forming method, the silicon content in the organic silicon film 116 is preferably 10 to 65 parts by weight based on 100 parts by weight of the solid content of the organic silicon film. If the amount is less than 10 parts by weight, even if ultraviolet light or heating is performed on the organosilicon film, Si
There is a possibility that the -O-Si bonding unit is not sufficiently generated, and the etching selectivity to the resist pattern cannot be obtained when etching the organic silicon film. 6
If the amount exceeds 5 parts by weight, the stability of the coating film will be lost.

Next, a resist pattern is formed on the organic silicon film 116. In forming the resist pattern, first, a resist film 117 is formed on the organic silicon film 116 as shown in FIG. By reducing the thickness of the resist film 117, the exposure latitude, focus latitude, or resolution can be improved. Therefore, the thickness of the resist film 117 may be small as long as the organic silicon film 116 can be etched with good dimensional control, and is preferably 0.01 to 10 μm.

The resist composition for forming the resist film 117 is not particularly limited as long as it is a composition that can be patterned by exposure to visible light, ultraviolet light, or the like, and a positive or negative type is selected and used. Can be. Specifically, the resist film 117 can be formed under the same conditions as described above using the resist composition as described in the first pattern forming method. An upper antireflection film for reducing multiple reflections generated in the resist film when performing light exposure, or an upper antistatic film for preventing charge-up that occurs when performing electron beam exposure, is provided with a resist film. 117 may be formed on the upper layer.

By selectively exposing a predetermined area of the resist film 117 thus formed to form a latent image, and selectively dissolving and removing the latent image portion with a developing solution, as shown in FIG.
A resist pattern 118 as shown in FIG. As the exposure light for forming a latent image on the resist film and the developing solution for dissolving and removing the latent image portion, the same exposure light and developing solution as in the first pattern forming method can be used.

Next, as shown in FIG. 3A, the organic silicon film 1
16 is irradiated with ultraviolet light 119 to oxidize at least an exposed portion of the organic silicon film (a region not covered with the resist pattern 118) in the organic silicon film. It is desirable that the ultraviolet light irradiated here contains light having a wavelength shorter than 450 nm. Light with a wavelength longer than 450 nm has insufficient energy to break the bond between silicon and silicon constituting the main chain of the organosilicon compound, and the organic silicon film 116 may not be sufficiently glassy. is there. As a light source that can be used, for example, a mercury lamp, an excimer lamp, and XeF (wavelength =
351 nm), XeCl (wavelength = 308 nm), KrF
(Wavelength = 248 nm), KrCl (wavelength = 222 n)
m), ArF (wavelength = 193 nm), and excimer laser such as F ₂ (wavelength = 151 nm).

The irradiation amount of the ultraviolet light is 0.01 to 1
It is preferably in the range of 000 J / cm ² .
If it is less than 0.01 J / cm ² , it is difficult to sufficiently oxidize the organic silicon film 116, while 10,000 J / cm ² is difficult.
If it exceeds / cm ² , the resist pattern may undergo photolysis and contract.

By irradiating the ultraviolet light 119, the exposed portion of the organic silicon film 116 (the portion not covered with the resist pattern 118) 116a firstly has the Si-Si bond of the main chain in the organic silicon compound or the main portion. The bond between the silicon of the chain and the side chain is cleaved, resulting in a dangling bond of silicon. Oxygen is bonded to this dangling bond and an oxidation reaction proceeds. Region 116b of organic silicon film 116 covered with resist pattern 118
With respect to, when ultraviolet light having high transmittance in the resist pattern 118 is used, oxidation proceeds similarly to the exposed portion 116a, but when ultraviolet light having low transmittance is used, oxidation does not progress . In the pattern forming method of the third invention, the region 116a of the organic silicon film not covered with the resist pattern 118 must be oxidized, but the region 116b covered with the resist pattern must be oxidized.
Does not necessarily need to be oxidized.

The resist pattern 118 depends on the material of the film 115 to be processed under the organic silicon film 116.
The oxidation state of the region 116b which is not covered with the first region can be selected. For example, when the processing target film 115 is etched with a fluorine-based gas using the organic silicon film pattern as a mask, it is preferable that the region 116b covered with the resist pattern 118 is not oxidized. This is because when the region 116b covered with the resist pattern 118 has a silicon oxide-like film quality, the resistance of the organic silicon film pattern as an etching mask during etching of the processing target film 115 is deteriorated. In this case, the energy transmittance of the ultraviolet light per 1 μm of the resist pattern is preferably 10% or less. On the other hand, when the processing target film 115 is etched with a chlorine-based gas or a bromine-based gas using the organic silicon film pattern as a mask,
Region 116b covered with resist pattern 118
Is desired to have a silicon oxide-like film quality. When the film quality is silicon-like, the resistance of the organic silicon film pattern as an etching mask at the time of etching the processing target film 115 is enhanced. Therefore, it is preferable to oxidize the region 116b covered with the resist pattern 118, and it is preferable that the energy transmittance of the ultraviolet light per 1 μm of the resist pattern is 5% or more.

If the region 116b covered with the resist pattern 118 can be oxidized, it is not always necessary to oxidize the region by irradiating ultraviolet light, and the organic silicon film 116 may be thermally oxidized by heating. The heating method in this case is not particularly limited, and examples thereof include a hot plate, an oven, and lamp heating. The heating can be performed at a temperature such that the temperature of the organic silicon film 116 becomes 50 to 180 ° C. preferable. Heating temperature is 5
If the temperature is lower than 0 ° C., the oxidation does not sufficiently proceed, while if the temperature exceeds 180 ° C., the resist pattern 118 flows and is deformed. When a predetermined region of the organic silicon film is oxidized by heating, the organic silicon compound contained in the organic silicon film preferably has a structure in which hydrogen atoms are bonded to silicon in the main chain. Examples include the structures represented by the aforementioned chemical formulas [1-1] to [1-26].

When the organic silicon film 116 is oxidized by either ultraviolet light irradiation or heating, the composition ratio of silicon, oxygen, and carbon in the exposed portion 116a of the organic silicon film 116 falls within a predetermined range. Is preferred. Specifically, silicon contained in the organic silicon film,
The numbers of oxygen and carbon atoms are p, q and r, respectively.
Then, it is preferable to oxidize so as to satisfy the relationship of q / p ≧ 0.1 and r / p ≦ 0.8. q / p <0.1
Alternatively, when r / p> 0.8, the organic silicon film 116 is used with the resist pattern 118 as an etching mask.
When etching is performed, a fluorocarbon-based polymer film is deposited on the surface of the organic silicon film 116, so that the organic silicon film is hardly etched, and the selectivity with respect to the resist decreases. As a result, the resist pattern 118 is not completely removed during the etching of the organic silicon film 116 or retreats, so that it becomes difficult to process the organic silicon film 116 with good dimensional control.

Next, by using the resist pattern 118 as an etching mask, the oxidized portion of the organic silicon film 116 is selectively removed by dry etching, whereby the organic silicon film shown in FIG. A film pattern 116b is formed. As described above, since the exposed portion 116a of the organic silicon film is modified into silicon oxide-like, a fluorine-based gas, that is, a source gas containing fluorine is used while maintaining a high etching selectivity with respect to the resist pattern 118. Organic silicon film 1
16 can be etched. Such etchants include, for example, SF ₆ , CF ₄ , CHF ₃ ,
Gases such as C ₂ F ₆ , C ₄ F ₈ , and CF ₄ are mentioned, and O ₂ , Ar, CO, H _2, or the like may be added to these gases and used as a source gas.

Examples of the etching apparatus include a reactive plasma etching system, a magnetron reactive plasma etching system, an electron beam plasma etching system,
An etching apparatus such as a TCP etching method, an ICP etching method, or an ECR plasma etching method can be used, and the degree of vacuum is preferably in the range of 1 × 10 ⁻⁴ torr to 10 torr. 1 × 10
^{If the} degree of vacuum is less than ^-4 torr, the processed shape is tapered, while if it exceeds 10 torr, the in-plane uniformity of the etch rate may be reduced. Further, the excitation power is preferably 0.01 to 100 W / cm ² . 0.01W
/ In cm less than ² slow throughput and reduced etch rate and etching the oxide portion of the lower film at a high selectivity to the resist pattern exceeds 100W / cm ² becomes difficult.

Through the above-described steps, the organic silicon film 116 is formed.
By etching, the etching selectivity of the organic silicon film to the resist pattern 118 can be set to 3 or more. As a result, the thickness of the resist film can be reduced to the same thickness as that of the organic silicon film 116, and the exposure margin or focus margin at the time of pattern exposure can be increased. The present inventors considered the reason why a high selectivity can be obtained as follows. That is, in the above-described gas system, fluorocarbon-based deposits that suppress the progress of etching are easily deposited on the surface of the resist pattern 118, whereas the oxidized organic silicon film is difficult to deposit because it contains a large amount of oxygen. That's why.

Thus, it is possible to form an organic silicon film pattern by transferring the fine resist pattern onto the organic silicon film with high dimensional accuracy. Specifically, the dimension (X ₂ ) of the resist pattern shown in FIG.
And the dimension conversion difference defined by the difference (Y ₂ −X ₂ ) between the size (Y ₂ ) of the organic silicon film pattern shown in FIG. 3B can be suppressed to 10 nm or less.

Next, as shown in FIG. 3C, the processed film 115 is etched to form a processed film pattern 115b. In this step, in particular, the processing target film 115 is made of a silicon-based insulating film, for example, a silicon oxide film, a silicon nitride film,
In the case of a silicon oxynitride film; a spin-on-glass film, a blank material used for manufacturing a mask, or the like, etching can be performed using a source gas containing fluorine. Therefore, after the oxidized portion of the organic silicon film 116 is etched, the processed film 115 can be etched using the same chamber. As a result, the throughput is improved as compared with the case where the organic silicon film 116 and the processing target film 115 are etched in separate chambers.

Next, the pattern forming method of the fourth invention will be described.

FIGS. 4 and 5 are process sectional views showing an example of the pattern forming method of the fourth invention.

First, an organic silicon film 201 is formed on a silicon wafer 200 as shown in FIG.
The organic silicon film 201 contains an organic silicon compound having a bond between silicon and oxygen in its main chain, and is suitably used as an interlayer insulating film of a semiconductor device.

The thickness of the organic silicon film 201 is 0.00
It is preferably about 5 to 5 μm. Thickness 0.00
If the thickness is less than 5 μm, the insulating effect as an interlayer insulating film is insufficient, while if it exceeds 5 μm, a significant difference in dimensional conversion may occur when processing the organic silicon film.

In the fourth method of the present invention, the organic silicon film 201 is formed by applying a solution or
Although a film can be formed on a film to be processed by a vapor phase method such as a VD method (chemical vapor deposition method), it is preferable to form an organic silicon film by a coating method. This is because the coating method has a simpler process cost than the CVD method.

That is, in the fourth pattern forming method of the present invention, except that an organic silicon compound having a bond between silicon and oxygen in the main chain is used, the same coating method as in the first pattern forming method described above is used. An organic silicon film can be formed by the method. Examples of the organosilicon compound that can be used include, for example, the following chemical formulas [PSO-1] to
A polysiloxane represented by [PSO-9] is exemplified. In addition, a copolymer represented by [PSO-8] and [PSO-9] may be used.

[0195]

Embedded image

[0196]

Embedded image

In the above formula, R ⁶¹ , R ⁶² and R
⁶³ is a hydrocarbon atom, or a substituted or unsubstituted aliphatic or aromatic hydrocarbon having 1 to 20 carbon atoms, and m and n are integers.

The weight average molecular weight of such a compound is not particularly limited, but is preferably from 200 to 100,000 for the same reason as in the case of the first pattern forming method described above.

The organic silicon compound is not limited to one kind, but may be a mixture of several kinds. Also,
If necessary, a thermal polymerization inhibitor for improving storage stability and an adhesion improver for improving adhesion to the silicon-based insulating film may be added. Those described in the formation method can be used.

Further, in order to lower the dielectric constant, oxides of heavy metals such as titanium and zirconium, or polyimides may be added. When a heavy metal oxide or polyimide is added, it may be copolymerized with the organosilicon compound.

In the fourth pattern forming method, a coating material as a raw material of an organic silicon film is prepared by dissolving a predetermined organic silicon compound and, if necessary, another compound in an organic solvent. Wafer 2
Then, the organic silicon film 201 is formed by heating and applying the heat treatment. The organic solvent that can be used here, the heating conditions, and the like are the same as in the case of the first pattern forming method.

In the fourth pattern forming method, the contents of silicon, oxygen and carbon in the organic silicon film 201 are preferably within the following ranges. The silicon content is preferably 5 to 65 parts by weight based on 100 parts by weight of the solid content in the organic silicon film. If the silicon content is less than 5 parts by weight, the silicon oxide of the organic silicon film does not progress even when irradiated with ultraviolet rays, so that the selectivity to the resist cannot be obtained when the organic silicon film 201 is etched. If the content exceeds 65 parts by weight, the stability of the coating film is impaired.

Further, the content of oxygen is preferably 5 to 70 parts by weight based on 100 parts by weight of the solid content in the organic silicon film. If the oxygen content is less than 5 parts by weight,
When the organic silicon film 201 is etched, the selectivity with respect to the resist cannot be obtained. On the other hand, when it exceeds 70 parts by weight, the stability of the coating film is impaired.

Further, the content of carbon is preferably 1 to 50 parts by weight based on 100 parts by weight of the solid content in the organic silicon film. When the carbon content is 1 part by weight or less, the heat resistance of the coating film decreases, while when it exceeds 50 parts by weight, the decarbonization of the organic silicon film 201 does not progress even when irradiated with ultraviolet light, At the time of etching the organic silicon film, there is a possibility that a selective ratio to the resist cannot be obtained.

Next, as shown in FIG. 4B, a lower film 202 is formed on the organic silicon film 201 as needed.
When a resist film is patterned using light as a light source in forming a resist pattern in a later step, a material having an absorptivity to exposure light is used as the lower layer film 202.
Thereby, it is possible to prevent reflection of the exposure light into the resist film and obtain a resist pattern with good dimensional control.
On the other hand, when patterning a resist film using a charged beam as a light source, by using a conductive material as the lower layer film 202, it is possible to prevent charge accumulation on the resist film during exposure and obtain a resist pattern without displacement. Can be.

In any case, the thickness of the lower layer film 202 is preferably 0.01 to 5.0 μm. 0.01
When the thickness is less than μm, reflection of exposure light or accumulation of charges cannot be sufficiently suppressed. On the other hand, when the thickness exceeds 5.0 μm, a resist pattern is formed on the organic silicon film 2 by dry etching.
This is because when the pattern is transferred to No. 01, a dimensional conversion difference occurs remarkably.

Next, a resist pattern is formed on the lower layer film 202. Here, since the lower layer film 202 is formed on the organic silicon film 201, a resist pattern is formed on the lower layer film. However, a resist pattern can be formed directly on the organic silicon film 201. In forming the resist pattern, first, as shown in FIG. 4C, a resist film 203 is formed on the lower layer film 202. When the thickness of the resist film 203 is reduced, the exposure margin such as the exposure latitude during exposure and the focus latitude, or the resolution can be improved accordingly. Therefore, the thickness of the resist film 203 is preferably as small as possible so long as the organic silicon film 201 can be etched with good dimensional control.
It is preferably from 0.01 to 10 μm.

The resist composition for forming the resist film 203 is not particularly limited as long as it is a composition that can be patterned by exposure to visible light, ultraviolet light, or the like. Can be. Specifically, the resist film 203 can be formed using the resist composition as described in the first pattern forming method under the same conditions as described above. An upper antireflection film for reducing multiple reflections generated in the resist film when performing light exposure, or an upper antistatic film for preventing charge-up that occurs when performing electron beam exposure, is provided with a resist film. 203 may be formed on the upper layer.

By selectively exposing a predetermined area of the resist film 203 thus formed to form a latent image, and selectively dissolving and removing the latent image portion with a developing solution, as shown in FIG.
A resist pattern 204 is formed as shown in FIG. As the exposure light for forming a latent image on the resist film and the developing solution for dissolving and removing the latent image portion, the same exposure light and developing solution as in the first pattern forming method can be used.

Next, the resist pattern 204 is transferred to the lower film, and as shown in FIG.
7 is formed. The transfer method here is not limited, and examples include a dry etching method.

Next, as shown in FIG. 5B, the obtained resist pattern 204 and lower layer pattern 207 are formed.
UV light from the top of the
Irradiation 8 decarbonizes at least the exposed portions of the organic silicon film (regions not covered with the resist pattern 204 and the like). It is desirable that the ultraviolet light irradiated here includes light having a wavelength shorter than 450 nm. In the case of light having a wavelength longer than 450 nm, the energy for breaking the bond between silicon and the organic group in the main chain of the organosilicon compound is insufficient, and the carbon component from the organosilicon film is sufficiently removed to decarbonize. May not be possible. Examples of the light source that can be used include those described for oxidizing the organic silicon film in the above-described second pattern formation method.

The irradiation amount of the ultraviolet light is 0.01 to 1
It is preferably in the range of 000 J / cm ² .
If it is less than 0.01 J / cm ² , it is difficult to sufficiently decarbonize the organic silicon film 201, while it is 10,000.
If it exceeds J / cm ² , the resist pattern 204 undergoes photolysis and contracts.

By irradiating the ultraviolet light 209, in the exposed portion (portion not covered with the resist pattern 204) 201a of the organic silicon film, first, the bond between the silicon of the main chain in the organic silicon compound and the organic group is formed. Cleavage results in dangling bonds of silicon. Oxygen bonds to this dangling bond, and the decarbonization reaction proceeds. In the fourth invention, the exposed portion 2 of the organic silicon film 201
01a must be decarbonized. In particular, the atomic ratio of carbon to silicon (C / Si
= The number of carbon atoms / the number of silicon atoms) and k is 0.95 after irradiation with ultraviolet light.
Decarbonization is performed so as to be × k or less. If it is larger than 0.95 × k, decarbonization is insufficient, so that improvement in resist selectivity cannot be expected.

On the other hand, it is desirable not to decarbonize the region 201b covered with the resist pattern 204. This is because, if the decarbonization proceeds in this portion, there is a possibility that the inconvenience that the dielectric constant of the organic silicon film pattern obtained after the processing is increased may occur. Such inconvenience can be prevented by using a material having a low transmittance with respect to ultraviolet light irradiated for decarbonization as the resist film 203 or the lower film 202. By using a material having a low transmittance, the resist pattern 20 can be formed.
4 or the lower film pattern 207 acts as a photomask, so that in the region 201b of the organic silicon film covered with the resist pattern 204 or the lower film pattern 207, the decarbonization reaction hardly proceeds, and the dielectric constant increases. Can be prevented. If the lower film 202 has a high transmittance with respect to ultraviolet light irradiated for decarbonization, after forming the resist pattern 204 and before etching the lower film 202, The organic silicon film 201 may be irradiated with ultraviolet light.

Next, using the resist pattern 204 and the lower layer film pattern 207 as an etching mask, the decarbonized portion of the organic silicon film 201 is selectively removed by dry etching to obtain a structure shown in FIG. The organic silicon film pattern 201b as shown in FIG.
Is formed. As described above, the exposed portion 201a of the organic silicon film is improved to silicon oxide-like,
Using a fluorine-based gas, that is, a source gas containing fluorine, the organic silicon film 201 can be etched while maintaining a high etching selectivity with respect to the resist pattern 204 and the like. The etchant, the etching apparatus, and the conditions that can be used here are the same as those in the above-described third pattern forming method.

Through the above-described steps, the organic silicon film 201
By etching, the etching selectivity of the organic silicon film to the resist pattern 204 can be set to 3 or more. As a result, the thickness of the resist film can be reduced, and the resolution during pattern exposure or the exposure margin can be increased. The present inventors considered the reason why a high selectivity can be obtained as follows. That is, while the fluorocarbon-based deposit that suppresses the progress of etching in the above-described gas system is easily deposited on the surface of the resist pattern 204, the decarbonized organic silicon film forms the fluorocarbon-based deposit. This is because the etching rate of the organic silicon film 201 is improved because it does not contain a carbon component. In addition, after decarbonization, organic groups are cut or oxygen is bonded to silicon, and oxidation occurs,
This is because the oxidation makes it difficult for fluorocarbon-based deposits to be deposited, and the etch rate of the organic silicon film 201 has been improved.

[0219]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings and specific examples. (Embodiment I) In this embodiment, first and second pattern forming methods will be described. (Embodiment I-1) Hereinafter, this embodiment will be described with reference to FIG.

First, a film to be processed is formed on the silicon wafer 10.
500 nm thick SiO as 11 _TwoLPCVD method
Formed.

On the obtained SiO ₂ film 11 as a film to be processed, the following methods (S1) to (S9) are used.
An organic silicon film 12 as shown in FIG. 1A was formed. (S1) Weight average molecular weight 1 as organosilicon compound
1,000 compounds [1-84] (n / m = 1/4) 1
0 g was dissolved in 90 g of anisole to prepare a solution material. This is processed by spin coating to form a film to be processed (SiO ₂
Film) 11 and then 160 ° C on a hot plate
The organic silicon film 12 was formed by heating for 90 seconds. (S2) Weight average molecular weight 1 as organosilicon compound
1,000 compounds [1-103] (n / m = 1/4)
10 g was dissolved in 90 g of anisole to prepare a solution material. Using this, an organic silicon film was formed on the processing target film 11 in the same procedure as in (S1). (S3) Compound [1-100] having a weight average molecular weight of 9,000 as an organosilicon compound (n / m = 1/4)
10 g was dissolved in 90 g of anisole to prepare a solution material. Using this, an organic silicon film was formed on the processing target film 11 in the same procedure as in (S1). (S4) 10 g of a compound [1-50] having a weight average molecular weight of 9,000 as an organosilicon compound was added to anisole 9
0 g to prepare a solution material. Using this,
An organic silicon film is formed into a film to be processed 11 in the same procedure as (S1).
Formed on top. (S5) Weight average molecular weight 1 as organosilicon compound
3,000 compounds [1-118] (n / m = 4/1)
10 g was dissolved in 90 g of anisole to prepare a solution material. Using this, an organic silicon film was formed on the processing target film 11 in the same procedure as in (S1). (S6) As the organosilicon compound, a weight average molecular weight of 2,
9 g of the compound [1-1], 1.8 g of the compound [3-8] as a crosslinking agent, and 0.2 g of the compound [4-12] as a radical generator are dissolved in 90 g of anisole to prepare a solution material. did. This was applied onto the film to be processed (SiO ₂ film) 11 by spin coating, and then heated at 160 ° C. for 90 seconds using a hot plate in a nitrogen atmosphere (oxygen concentration: 50 ppm or less). (S7) As the organosilicon compound, a weight average molecular weight of 4,
A solution material was prepared in the same manner as in (S6), except that 9 g of the compound [1-23] (n / m = 9/1) was used. A silicon film 12 was formed on the film to be processed (SiO ₂ film) 11. (S8) As the organosilicon compound, a weight average molecular weight of 3,
9 g of compound [1-24] (n / m = 1/4)
A solution material was prepared in the same manner as in (S6) except that was used, and an organic silicon film 12 was formed on the film to be processed (SiO ₂ film) 11 by using this in the same procedure as in (S6). (S9) A solution material was prepared in the same manner as in (S6) except that 1.8 g of the compound [3-62] was used as a crosslinking agent, and this was used to prepare an organic material in the same procedure as in (S6). A silicon film 12 was formed on the film to be processed (SiO ₂ film) 11.

Each of the organic silicon films has a thickness of 200
nm.

For each organic silicon film, the complex refractive index at the exposure wavelength (248 nm) was measured using spectral ellipsometry, and the results are summarized in Table 1 below.

[0222]

[Table 1]

As shown in Table 1, (S1) to (S1)
9), the exposure light (248n)
It can be seen that it has absorptivity to m) and acts as an antireflection film.

Next, a resist solution is applied on each organic silicon film 12 by a spin coating method, and baked on a hot plate at 110 ° C. for 90 seconds.
A resist film 13 was formed as shown in FIG. The resist solution used here had a weight average molecular weight of 18,00.
5 g of polyvinyl phenol having a weight average molecular weight of 22,000 in which 50% of hydroxyl groups have been substituted with tertiary butoxycarbonyl groups, and 0.1 g of triphenyl sulfonate as an acid generator
Is a positive chemically amplified resist prepared by dissolving the compound in 90 g of ethyl lactate.

The film thickness of the obtained resist film 13 is 200 n
m.

Next, as shown in FIG. 1C, the resist film is subjected to pattern exposure through a predetermined mask using a reduction optical type stepper using KrF excimer laser light as a light source, 110 ° C using a plate
For 90 seconds. The resist film 13 after baking is subjected to a development process using 0.21 N tetramethylammonium hydroxide,
The exposed portion 13a of the resist film is dissolved and removed, and FIG.
The line and space pattern 13b of 0.15 μm as shown in FIG.

When the cross-sectional shape of the resist pattern 13b was observed by using a scanning electron microscope, it was found that the resist pattern had no profile and had a good profile on any of the organic silicon films as shown in FIG. A pattern was obtained. No residue was observed between the resist patterns. The thickness of the resist pattern after development is
In each case, it is 195 nm.

Using the obtained resist pattern 13b as a mask, the exposed portions (portions not covered by the resist pattern) of the organic silicon film 12 were selectively oxidized as shown in FIG. 1 (e). In the oxidation treatment, the following methods (P1) to (P4) were used. Note that (P
The irradiation dose when irradiating the energy beams 1) to (P3) was a value described in Tables 2 to 4. (P1) The entire surface of the wafer was irradiated with an F ₂ laser (wavelength: 157 nm). (P2) The entire surface of the wafer was irradiated with an excimer lamp (center wavelength: 172 nm, bandwidth: 10 nm). (P3) The entire surface of the wafer was irradiated with an electron beam at an acceleration voltage of 10 keV. (P4) Using a down flow plasma apparatus, source gas O ₂ = 100 SCCM, excitation power 300 W, degree of vacuum 4
Oxygen plasma was generated and irradiated over the entire surface under the conditions of 5 mTorr.

Next, the oxidized portion 12a of the organic silicon film is dissolved and removed using a solution containing a fluorine atom or an alkaline aqueous solution to form an organic silicon film pattern 12b as shown in FIG. Formed. The following (D1) to (D3) and (D6) were used as the solution containing a fluorine atom, and the following (D4) and (D5) were used as the alkaline aqueous solution. (D1) Processing solution obtained by diluting 1 volume of hydrogen fluoride with 99 volumes of pure water (D2) Processing solution obtained by diluting 1 volume of ammonium fluoride with 99 volumes of pure water (D3) 1 volume of hydrogen fluoride and 6 volumes of ammonium fluoride (D4) 0.21 N tetramethylammonium hydroxide (D5) 0.27 N ammonium hydroxide Also, 1 volume of hydrofluoric acid was purified as (D6). The treatment liquid diluted with 9 volumes of water was heated to 100 ° C., and the wafer was placed in dilute hydrofluoric acid vapor to dissolve and remove the portions of the organic silicon film that had been oxidized.

As a result, in any combination, FIG.
As shown in (f), it was able to be dissolved and removed with good anisotropy. Next, in order to examine a dimensional conversion difference caused by the oxidation process and the dissolution removal process of the oxidized portion, the size of the resist pattern 13b formed on the organic silicon film 12 (FIG. 1D)
And X ₁ defined) of, Y ₁ dimension of the organosilicon film pattern 12b formed by dissolving and removing the oxidized part (FIG. 1 (f)
) (= Y ₁ −X ₁ ). The measurement results of the dimensional conversion difference are shown in Tables 2 to 4 together with the type of the organic silicon film, the oxidation method and the dissolution removal method.

[0231]

[Table 2]

[0232]

[Table 3]

[0233]

[Table 4]

In each case, the resist pattern 13b could be transferred onto the organic silicon film 12 with good controllability with a dimensional difference within a tolerance of 9 nm or less. Further, the film thickness of the resist pattern 13b after the development processing of the organic silicon film was measured, and the results are also shown in Tables 2 to 4. These tables show that the remaining film thickness of the resist pattern is at least 150 nm or more. In particular, (D1) to (D3) and (D6), that is, those obtained by dissolving and removing the organic silicon film in an atmosphere containing a fluorine atom, show that the amount of film loss of the resist pattern is small. Since the thickness of the organic silicon film pattern 12b is 200 nm, the organic silicon film pattern 12b
The thickness of the mask material pattern including the resist pattern 13b and the resist pattern 13b is 350 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (SiO ₂ film) in the next step. (Comparative Example I-1) A lower layer film was formed from a lower layer film material used in the conventional PCM method, a 0.15 μm line and space resist pattern was transferred to the lower layer film, and the shape of the obtained lower layer film pattern was obtained. Was examined.

First, a 500 nm thick SiO ₂ film was formed as a film to be processed on a silicon wafer by the LPCVD method in the same manner as in the above-described embodiment.

On the obtained film to be processed (SiO ₂ film),
Underlayer films were formed by the following methods (C1) to (C6). (C1) 9.8 g of a novolak resin having a weight average molecular weight of 15,000, and 0.1 g of diazonaphthoquinone as a photosensitive agent.
2 g was dissolved in 90 g of ethyl lactate to prepare a solution material. This is processed by spin coating to form a film to be processed (SiO ₂
On the hot plate at 110 ° C.
Heating was performed for 0 seconds to form a lower layer film. (C2) A solution material was prepared by dissolving 10 g of polymethyl methacrylate having a weight average molecular weight of 13,000 in 90 g of cyclohexanone. This was applied on a film to be processed (SiO ₂ film) by spin coating, and then heated at 110 ° C. for 90 seconds on a hot plate to form a lower layer film. (C3) 9.3 g of a novolak resin having a weight average molecular weight of 15,000, 0.2 g of diazonaphthoquinone as a photosensitive agent,
And anthracene 0.5 as a dye absorbing the exposure light
g was dissolved in 90 g of ethyl lactate to prepare a solution material. This is processed by spin coating to form a film to be processed (SiO ₂
On the hot plate at 110 ° C.
Heating was performed for 0 seconds. (C4) A solution material was prepared by dissolving 9.5 g of polymethyl methacrylate having a weight average molecular weight of 13,000 and 0.5 g of anthracene as a dye absorbing exposure light in 90 g of cyclohexanone. This was applied on a film to be processed (SiO ₂ film) by spin coating, and then heated at 110 ° C. for 90 seconds on a hot plate to form a lower layer film. (C5) A lower layer film was formed using the same solution material as in (C4) in the same manner as in (C4), and the entire surface was irradiated with an ArF excimer laser to crosslink the surface of the lower layer film. (C6) Polysulfone 1 having a weight average molecular weight of 6,000
0 g was dissolved in 90 g of cyclohexanone to prepare a solution material. This is processed by spin coating to form a film to be processed (S
iO ₂ film) was applied on, 220 on a hot plate
Heating was performed at 90 ° C. for 90 seconds to form a lower layer film.

The thickness of each of the lower layers is 200 nm.

For each lower layer film, the complex refractive index at the exposure wavelength (248 nm) was measured using spectral ellipsometry, and the results are summarized in Table 5 below.

[0239]

[Table 5]

As shown in Table 5, with respect to (C1) and (C2), there was almost no absorption at the exposure wavelength (248 nm), and it was found that the film did not act as an antireflection film.

Next, an underlayer film (C
3) On (C4), (C5) and (C6), the formation of a resist film was attempted in the same manner as in the above-described embodiment.
Regarding (C3), the lower layer film was dissolved in the resist solvent, and the lower layer film was completely dissolved during the application of the resist.
On the other lower layer films, the resist solution could be normally applied, and subsequently, the resist film was formed by baking under the same conditions as in the example.

On the lower layers (C4), (C5) and (C6) where the application of the resist solution could be performed normally,
A resist pattern was formed by pattern exposure and development under the same conditions as in the example, and the cross-sectional shape of the obtained resist pattern profile was observed using a scanning electron microscope.

On the lower layer films (C4) and (C5), footing 24 occurred as shown in FIG. 9, and a resist profile having a good sectional shape could not be obtained. Also,
The generation of residues between the resist patterns 23 was remarkable. The cause of this is that the resistance of the lower film 22 to the solvent of the resist is not perfect, the mixing between the resist and the lower film is not completely suppressed, and the dye contained in the lower film 22 It is considered that the lower part of the resist film hardly dissolved in the developer.

Only on the lower layer film (C6), it was possible to obtain a resist pattern having a good shape without footing as in the case of the example.

The lower layer film (C6) is irradiated with an excimer lamp using a resist pattern as a mask.
Irradiation was performed at 0 J / cm ² to expose the exposed portion of the underlayer film (the portion not covered with the resist pattern). Subsequently, a methyl isobutyl ketone solution was applied onto the wafer, and an attempt was made to dissolve and remove the photosensitive portion of the lower layer film.

The cross section of the processed lower layer film pattern was observed with a scanning electron microscope, and the outline of the shape is shown in FIG. As shown in the figure, one layer remains on the surface of the SiO ₂ film. Excimer lamp irradiation amount is 3.0J
/ Cm ² , there is no more residue as shown in FIG.
The shape of No. 5 became a bowing shape and could not be patterned with good anisotropy. (Comparative Example I-2) Development of the organic silicon film was attempted in the same manner as in the above (Example I-1) except that the oxidation treatment was not performed on the organic silicon film.

The dissolving and removing method corresponding to the type of the organic silicon film was as shown in Tables 2 to 4 above. In any of the combinations, the organic silicon film was not dissolved and removed.

From this comparative example, it can be seen that the organic silicon film according to the present invention cannot be removed by development in an atmosphere containing a fluorine atom or an alkaline aqueous solution unless oxidation treatment is performed. (Comparative Example I-3) An organic silicon film was developed by the same method as in the above (Comparative Example I-2) except that toluene was used as a developer. As a result, all the portions of the organic silicon film covered with the resist pattern were dissolved and removed together with the exposed portions, and the organic silicon film could not be patterned.

The organic silicon film according to the present invention has a low polarity and is dissolved in a non-polar solvent such as toluene. However, if the development treatment is performed without performing the oxidation treatment, the entire organic silicon film is dissolved and the organic silicon film is dissolved. It can be seen that patterning cannot be performed. (Comparative Example I-4) The development of the organic silicon film was attempted in the same manner as in (Example I-1) described above, except that the developing treatment was performed using toluene.

The dissolving and removing method corresponding to the type of the organic silicon film was as shown in Tables 2 to 4 above. In any of the combinations, the organic silicon film was not dissolved and removed.

From this comparative example, it is considered that the organic silicon film according to the present invention became higher in polarity by the oxidation treatment and became less soluble in a nonpolar solvent. (Embodiment I-2) Another embodiment of the present invention will be described with reference to FIG.

First, a film to be processed 11 was formed on a silicon wafer 10 in the same manner as in (Example I-1).

Next, 10 g of polyvinylphenol having a weight average molecular weight of 12,000 was dissolved in 90 g of ethyl lactate to prepare a solution to be used as a material for the etching stopper film.
This solution is applied on the film to be processed by spin coating, and then baked at 320 ° C. for 90 seconds using a hot plate to form a thin film resistant to fluorine (etching stopper film) as shown in FIG. 17) was formed. The thickness of the thin film is 30 nm.

Next, an organic silicon film 12 is formed on a fluorine-resistant thin film by the same method as in (S1) of (Example I-1), and the method of (Example I-1) is used. 6
As shown in (e), a resist pattern 13b was formed on the organic silicon film.

Subsequently, the entire surface of the wafer was irradiated with the excimer lamp used in (Example I-1) at a dose of 1.5 J / cm ² , and the resist pattern of the organic silicon film was changed as shown in FIG. The uncoated areas were selectively oxidized.

Further, the oxidized portion of the organic silicon film was dissolved and removed by using a processing solution obtained by diluting 1 volume of hydrogen fluoride with 9 volumes of pure water, and the organic silicon film as shown in FIG. A film pattern 12b was obtained. The treatment liquid used here has a high concentration of hydrogen fluoride of 10 times or more as compared with that used in (Example I-1).

In the case of diluting 1 volume of hydrogen fluoride with 99 volumes of pure water (Example I-1), the treatment time was 182 seconds. However, in the case of this example, the concentration of hydrogen fluoride was increased. The processing time was reduced to 13 seconds. The same values as in Example I-1 were obtained for the shape of the organic silicon film pattern, the dimensional conversion difference caused by the oxidation treatment and the dissolution removal treatment of the oxidized portion, and the remaining film of the resist pattern after the development treatment. Thus, it was possible to achieve both of these performances and shortening of the development processing time. (Comparative Example I-5) When a thin film having resistance to fluorine was not formed in (Example I-2), FIG.
As shown in (b), the film to be processed was isotropically etched by hydrofluoric acid.

From the results of this comparative example, it was found that by forming a fluorine-resistant thin film between the film to be processed and the organic silicon film, the organic silicon film was developed using a processing solution having a high hydrogen fluoride concentration. It can be seen that, even when the process is performed, the development processing time can be reduced without etching the film to be processed.

The present invention has been described above with reference to the case where the organic silicon film formed on the film to be processed is used as an antireflection film for photolithography.
It is not limited to this. For example, the above-described organic silicon film can be used as an antistatic material for preventing displacement due to charge accumulation for charged beam lithography.

An example in which the film is used as an antistatic film formed on a film to be processed will be described below. (Example I-3) First, a film to be processed was formed on a silicon wafer in the same manner as in (Example I-1).

Next, a compound [1-84] having a weight average molecular weight of 11,000 (n / m = 1) was used as an organosilicon compound.
/ 4) 9.9 g and 0.1 g of triphenylsulfonate as a conductive substance were dissolved in 90 g of anisole to prepare a solution material. Using this solution, an organic silicon film was formed on the film to be processed in the same procedure as (S1) in (Example I-1). The thickness of the organic silicon film was 200 nm.
When the sheet resistance of the organic silicon film was measured, 1.2
× 10 ¹⁰ Ω / □, a lower value than the sheet resistance of 8.2 × 10 ¹⁵ Ω / □ when no conductive substance was added. Therefore, the organic silicon film formed here can function as an antistatic film.

On the organic silicon film thus obtained,
A resist film was formed in the same manner as in (Example I-1).
The resist film was subjected to pattern exposure using an electron beam lithography system with an acceleration voltage of 50 eV, and then baked and developed in the same manner as in the example to form a 0.1 μm line and space pattern. The thickness of the resist pattern after the development was 192 nm.

When the obtained pattern was observed from above with a scanning electron microscope, a resist pattern could be formed without any displacement due to charge accumulation. This is presumably because the organic silicon film (antistatic film) had a sufficiently low sheet resistance, and the irradiated charges were dispersed throughout the antistatic film.

Next, the entire surface of the wafer was irradiated with the excimer lamp used in (Example I-1) at 2.0 J / cm ² to selectively oxidize the region of the organic silicon film not covered with the resist pattern. did.

Finally, the oxidized portion of the organic silicon film was dissolved and removed by the method (D1) of (Example I-1).

When the pattern was observed from a cross section with a scanning electron microscope, the shape of the antistatic film after the development treatment was a good vertical shape. Further, the thickness of the resist pattern after the development of the antistatic film was 190 nm, and the amount of film reduction due to the development of the antistatic film was suppressed to 2 nm or less. Since the thickness of the antistatic film is 200 nm, the thickness of the mask material pattern including the antistatic film pattern and the resist pattern is 392 nm. This thickness is sufficient as a mask required for etching the film to be processed (SiO ₂ film) in the next step. (Embodiment II) In this embodiment, a third pattern forming method will be described. (Example II-1) Hereinafter, this example will be described with reference to FIGS.

First, a silicon wafer 110 having a thickness of 3
A 00 nm SiO ₂ film 111 was formed by sputtering. On the SiO ₂ film 111, a metal wiring layer 115 as a film to be processed was formed by a sputtering method. The metal wiring layer 115 includes a TiN film 112 (thickness: 40 nm),
Film 113 (thickness: 5 nm), 0.5% -Cu-Al film 1
14 (thickness: 230 nm), Ti film 113 (thickness: 10
nm) and a TiN film 112 (film thickness: 20 nm) are sequentially formed.

The metal wiring layer 115 which is the obtained film to be processed
The organic silicon film 116 as shown in FIG. 2A is formed by using the following methods (S11) to (S16).
Was formed respectively. This organic silicon film 116 can be referred to as a lower film that functions as an antireflection film. (S11) Compound [1-84] having a weight average molecular weight of 12,000 as an organosilicon compound (n / m = 1/4)
10 g was dissolved in 90 g of anisole to prepare a solution material. This is applied on the film to be processed (metal wiring layer) 115 by a spin coating method, and then applied on a hot plate.
The organic silicon film 115 was formed by heating at 0 ° C. for 60 seconds. (S12) Compound [1-115] having a weight average molecular weight of 3,000 as an organosilicon compound (n / m = 4/6)
10 g was dissolved in 90 g of anisole to prepare a solution material. This is applied onto the film to be processed (metal wiring layer) 115 by spin coating, and then heated at 130 ° C. for 60 seconds using a hot plate in a nitrogen atmosphere (oxygen concentration 50 ppm or less) to form the organic silicon film 115. did. (S13) 10 g of a compound [3-89] having a weight average molecular weight of 2,500 as an organosilicon compound was added to anisole 9
0 g to prepare a solution material. Using this, an organic silicon film 116 was formed on the processed film 115 in the same procedure as in (S12). However, heating at 240 ° C is 6
0 seconds. (S14) 10 g of a compound [1-1] having a weight average molecular weight of 3,200 as an organosilicon compound and an organic silicon compound [3-8] having a weight average molecular weight of 3,200 as a crosslinking agent
9] (n / m = 1/1) 9 g, compound [4] as an initiator
-12] 1 g was dissolved in 90 g of anisole to prepare a solution material. Using this, in the same procedure as (S13),
An organic silicon film 116 was formed on the film 115 to be processed. (S15) Compound [1-120] having a weight average molecular weight of 5,200 as an organosilicon compound (n / m = 1/1)
10 g was dissolved in 90 g of anisole to prepare a solution material. Using this, an organic silicon film 116 was formed on the processing target film 115 in the same procedure as in (S13). (S16) Compound [1-119] having a weight average molecular weight of 2,500 as an organosilicon compound (n / m = 1/1)
10 g was dissolved in 90 g of anisole to prepare a solution material. Using this, an organic silicon film 116 was formed on the processed film 115 in the same procedure as in (S12).

The thickness of each organic silicon film is 20
It was set to 0 nm.

Next, a resist solution is applied on each organic silicon film 116 by spin coating, and baked on a hot plate at 140 ° C. for 90 seconds to form a resist film 117 as shown in FIG. Was formed. The resist solution used here had a weight average molecular weight of 1
Compound [P-1] (n
/ M = 1/1) 9.9 g and the compound [P
-2] is a positive chemically amplified resist obtained by dissolving 0.1 g in 90 g of ethyl lactate. The compounds used are shown below.

[0271]

Embedded image

The thickness of the obtained resist film 117 is 200
nm.

Next, the resist film 117 was subjected to pattern exposure using a reduction optical type stepper using an ArF excimer laser as a light source, and then baked at 140 ° C. for 90 seconds using a hot plate. By subjecting the baked resist film 117 to development processing using 0.26 N tetramethylammonium hydroxide, a 0.13 μm line and space pattern 118 as shown in FIG. 2C was formed. .

When the cross-sectional shape of the resist pattern 118 was observed using a scanning electron microscope, no wavy shape due to a standing wave was confirmed on any of the organic silicon films as shown in FIG. 2C. . This is because the reflection from the metal wiring layer 115 was suppressed by forming the organic silicon film 116 acting as an anti-reflection film.

The organic silicon film 116 on which the resist pattern 118 was formed was oxidized by the following method.

As shown in FIG. 3A, an ArF excimer laser 119 was applied to the organic silicon film 116 formed by the methods (S11) to (S15) in a nitrogen atmosphere (oxygen concentration: 1,000 ppm). The whole surface was irradiated.
At this time, the irradiation amount was adjusted according to the type of the organic silicon film, and irradiation was performed at the values shown in Table 6 below.

Further, the organic silicon film formed by the method (S16) was subjected to an oxidation treatment by heating at 140 ° C. for 3 minutes in the air using a hot plate.

After the oxidation treatment, the atomic ratio of oxygen to silicon in each region of the organic silicon film (O / Si = the number of oxygen atoms / the number of silicon atoms) and the atomic ratio of carbon to silicon (C / Si = Number of carbon atoms / number of silicon atoms) was measured using X-ray photoelectron spectroscopy. In addition,
Each region of the organic silicon film is a resist pattern 118
(Covered area) 116b and the area not covered by the resist pattern 118 (exposed area) 1
16a.

Table 6 below summarizes the atomic ratio in each region together with the atomic ratio in the organic silicon film before the oxidation treatment.

[0280]

[Table 6]

As shown in Table 6, the exposed portion 116a of the organic silicon film and the coating portion 116 of the organic silicon film
In b, the ratio of oxygen atoms to silicon (O / Si) increased, and the ratio of carbon atoms to silicon (C / Si) decreased, indicating that oxidation proceeded in any region. It is considered that the oxidation is progressing also in the organic silicon film covering portion 116b for the following reason. That is, the resist used in this example has a transmittance of about 85% per 1 μm at a wavelength of 193 nm, and has high transmittance with respect to an exposure wavelength.

When the resist pattern 118 before and after the oxidation treatment was observed by using a scanning electron microscope, no reduction in the film thickness of the resist pattern due to the oxidation treatment and no deformation of the pattern were observed.

Next, the organic silicon film was etched using a magnetron-type reactive ion etching apparatus.
An organic silicon film pattern 116 as shown in FIG.
b was formed. The etching conditions are as follows: source gas source gas C ₄ F ₈ / CO / Ar = 20/100 / 100SCC
M, degree of vacuum 75 mTorr, excitation power density 1.0 W / c
m ² , and the substrate temperature was 40 ° C. As a result, as shown in FIG. 3B, the organic silicon film 116 could be processed with any of the organic silicon films with good anisotropy.

Next, the organic silicon film 1 is etched.
To investigate the pattern shift occurring in 16, the size of the resist pattern 118 formed on the organic silicon film 116 (defined by X ₂ in FIG. 2 (c)), the dimensions of the organosilicon film pattern 116b after etching ( The difference (= Y ₂ −X ₂ ) from the value defined by Y ₂ in FIG. 3B was measured. Table 6 summarizes the measurement results of the dimensional conversion differences.

As shown in Table 6, in each case, the dimensional difference within the allowable range of 6.5 nm (5% of the processing size).
Thus, the resist pattern 118 was transferred to the organic silicon film 116 with good controllability.

Also, the etching of the oxidized portion of the organic silicon film 116 is stopped halfway, and the shaved amount of the resist pattern 118 and the shaved amount of the oxidized portion 116a of the organic silicon film are measured. (Etching rate of film / etching rate of resist pattern) was calculated. The results obtained are summarized in Table 6 above. As shown in Table 6, in each case, the organic silicon film 116 was etched at a high selectivity of 3 or more. As a result, the organic silicon film was anisotropically processed with good dimensional control, and the organic silicon film pattern 116b was obtained.

Subsequently, the metal wiring layer 115 is etched by using a magnetron-type reactive ion etching apparatus to form a metal wiring layer pattern 115 as shown in FIG.
b was formed. The etching conditions are source gas BCl ₃
/ Cl ₂ = 100/200 SCCM, vacuum degree 75mTo
rr, excitation power density 1.0 W / cm ² , substrate temperature 25 ° C.
And As a result, in each of the combinations, as shown in FIG. 3C, the metal wiring layer 115, which was a film to be processed, could be processed with good anisotropy. (Comparative Example II-1) A lower layer film was formed using an organic resin,
A 0.13 μm line and space resist pattern was transferred to the lower film, and the shape of the obtained lower film pattern was examined.

First, as in the above-described embodiment, a SiO ₂ film 111 and a metal wiring layer 115 as a film to be processed were formed on a silicon wafer by a sputtering method.

On the obtained metal wiring layer 115, a lower layer film was formed as follows. First, polysulfone 10g
Was dissolved in 90 g of cyclohexanone to prepare a solution material for the lower layer film. This solution material was applied on the metal wiring layer 115 by spin coating, and then baked at 220 ° C. for 60 seconds using a hot plate to evaporate and dry the solvent, thereby forming the lower film 116.

On the obtained lower layer film 116, a 0.13 μm line-and-space resist pattern 118 was formed in the same manner as in the above (Example II-1).

Next, using a magnetron type RIE apparatus,
The lower layer 116 was etched. Etchin in this case
The condition of the resist pattern 118 and the lower film 116 is
Conditions that maximize the etching selectivity, that is, source gas
CF_Four= 800 SCCM, O _Two= 8 SCCM, Ar = 1
60 SCCM, degree of vacuum 40 mTorr, excitation power 500
W. As a result, after the etching of the lower film 116 is completed.
The resist pattern 118 is almost not removed
And the underlying film cannot be etched vertically
Was. Stop etching of the lower layer film halfway and
When the strike selectivity was determined, it was found that there was only 1.20.
won.

When the organic resin as in the present comparative example is used as the lower film 116, the etching selectivity with respect to the resist pattern 118 cannot be obtained, so that the lower film 116 cannot be processed with good anisotropy. . (Comparative Example II-2) An attempt was made to etch the organic silicon film by the same method as in the above (Example II-1) except that the oxidation treatment was not performed on the organic silicon film. Incidentally, the organic silicon film is formed by the steps (S11) to (S1) in (Example II-1).
Each was formed by the method of 6).

As a result, the resist pattern 118 was not completely removed during the etching of the lower layer film 116, and the film to be processed could not be processed to a desired size. When the etching of the lower layer film was stopped halfway and the selectivity ratio of the lower layer film to the resist was examined, the lower layer film formed by any method was in the range of 0.9 to 1.1, and the selectivity was significantly reduced. I knew I was doing it.

From this comparative example, in order to improve the selectivity of the lower film 116 with respect to the resist, the exposed region 116 of the lower film was
It can be seen that a (a region not covered with the resist pattern) must be oxidized. (Comparative Example II-3) First, in the same manner as in (Example II-1), a film to be processed 115, an organic silicon film 116, and a resist pattern 118 were sequentially formed on a silicon wafer 110. Incidentally, the organic silicon film is formed by the above-mentioned (S1).
It was formed by the method of 1).

Next, using a plasma ashing apparatus,
The organic silicon film 116 was subjected to oxygen plasma treatment. The parameters of the source gas, the excitation power density, and the substrate density were O ₂ = 1000 SCCM, 1.0 W / cm ² , 12
It was kept constant at 0 ° C. The degree of vacuum is 10, 30, 50, 7
Oxygen plasma processing was performed at five levels of 0 and 90 mTorr, and the amount of film reduction of the resist pattern 118 ashed by the oxygen plasma processing was examined.

Further, in the same manner as in (Example II-1), the atomic ratio of oxygen to silicon (O / Si = the atomic number of oxygen / the atomic number of silicon) and the atomic ratio of carbon to silicon (C / Si = the number of carbon atoms / the number of silicon atoms).

Also, the organic silicon film 116 was formed as described in Example II.
Etching was performed in the same manner as in -1), and the selectivity to resist was examined. Table 7 shows the measurement results.

[0298]

[Table 7]

As shown in Table 7, when the degree of vacuum is reduced, the amount of oxygen radicals is reduced, so that the resist pattern 118 is hardly ashed, but the organic silicon film 116 is also hardly oxidized. For this reason, it is difficult to obtain a selective ratio with respect to the resist. On the other hand, when the degree of vacuum is increased, the amount of oxygen radicals is increased, so that the organic silicon film 116 is easily oxidized and the resist selectivity is improved, but the resist pattern 118 is easily ashed. In this case, the thickness of the resist pattern 118 is significantly reduced.

That is, when oxygen plasma treatment is used to oxidize the organic silicon film 116, it is found that the reduction in the film thickness of the resist pattern 118 cannot be suppressed and the selectivity to resist cannot be increased. (Reference Example II-1) First, a film 115 to be processed, an organic silicon film 116, and a resist pattern 118 are formed on a silicon wafer 110 by the same method as in Example II-1.
Formed sequentially on top. Note that the organic silicon film 116 was formed by the above-described method (S11).

In oxidizing the organic silicon film 116, the ArF excimer laser was irradiated at a dose of 9 mJ / cm ² at a lower dose than in the case of (Example II-1). The number of silicon, carbon, and oxygen atoms was determined. As a result, the atomic ratio of carbon to silicon (C / Si) and the atomic ratio of oxygen to silicon (O / Si) in the exposed region 116a of the organic silicon film are 0.11 and 8.03, respectively. The degree of oxidation was lower than that of Example II-1).

Subsequently, when the organic silicon film 116 was etched in the same manner as in (Example II-1), the selectivity of the organic silicon film to the resist was reduced to 1.52, and the organic silicon film 116 was etched. 8n
m, which exceeds the allowable range of 6.5 nm. (Reference Example II-2) First, a film 115 to be processed, an organic silicon film 116, and a resist pattern 118 are formed on a silicon wafer 110 by the same method as in Example II-1.
Formed sequentially on top. Note that the organic silicon film 116 was formed by the above-described method (S15).

In oxidizing the organic silicon film 116, the ArF excimer laser was irradiated at a dose of 9 mJ / cm ² at a lower dose than in the case of (Example II-1). The number of silicon, carbon, and oxygen atoms was determined. As a result, the atomic ratio of carbon to silicon (C / Si) and the atomic ratio of oxygen to silicon (O / Si) in the exposed region 116a of the organic silicon film are 0.12 and 8.12, respectively. The degree of oxidation was lower than that of Example II-1).

Subsequently, when the organic silicon film 116 was etched in the same manner as in (Example II-1), the selectivity of the organic silicon film with respect to the resist was reduced to 1.48. 7n
m, which exceeds the allowable range of 6.5 nm.

According to the present reference example, the number of silicon, carbon and oxygen atoms in the organic silicon film after irradiation with ultraviolet rays was
Atomic ratio of carbon to silicon (C / Si) ≧ 0.1,
And the atomic ratio of oxygen to silicon (O / Si) ≦
It can be seen that it is preferable to irradiate ultraviolet rays so as to satisfy 8.0. (Example II-2) Another example of the third pattern forming method will be described with reference to FIGS.

First, a 500 nm-thick TEOS oxide film 121 is formed on a silicon wafer 120 as a film to be processed by LP.
It was formed by a CVD method.

The TEOS oxide film 121 as the film to be processed is
Above (S11) to (S11) in the above (Example II-1).
An organic silicon film 122 as shown in FIG. 7A was formed by the same method as (S15). This organic silicon film 122 can be referred to as a lower layer film acting as an anti-reflection film.

Each organic silicon film has a thickness of 20
It was set to 0 nm.

Next, a resist solution is applied on each organic silicon film 122 by a spin coating method, and baked on a hot plate at 110 ° C. for 90 seconds to form a resist film 123 as shown in FIG. Was formed. The resist solution used here had a weight average molecular weight of 1
5 g of 8,000 polyvinyl phenols, 50 hydroxyl groups
% Of which is substituted with a tertiary butoxycarbonyl group.
g, and 0.1 g of sulfonimide as an acid generator
Is dissolved in 90 g of ethyl lactate.

The thickness of the obtained resist film 123 is 200
nm.

Next, the resist film 123 was subjected to pattern exposure using a reduction optical stepper using a KrF excimer laser as a light source, and then baked at 110 ° C. for 90 seconds using a hot plate. The resist film 123 after baking was developed using 0.21 N tetramethylammonium hydroxide to form a 0.15 μm line-and-space pattern 124 as shown in FIG. 7C. .

When the cross-sectional shape of the resist pattern 124 was observed using a scanning electron microscope, no wavy shape due to a standing wave was confirmed on any of the organic silicon films as shown in FIG. 7C. Was. This is because the reflection from the TEOS oxide film 121 was suppressed by forming the organic silicon film 122 acting as an anti-reflection film.

The oxidation treatment was performed on the organic silicon film 122 on which the resist pattern 124 was formed by irradiating it with ultraviolet rays 125 as shown in FIG. In the oxidation treatment, any of the following methods (P11) to (P13) was used. The combination of the type of the organic silicon film and the irradiation method is as shown in Table 8 below.
The values shown in the table were used. (P11) Under nitrogen atmosphere (oxygen concentration 1,000ppm)
Then, an ArF excimer laser was irradiated from above the wafer to the entire surface of the wafer. (P12) Under nitrogen atmosphere (oxygen concentration 1,000ppm)
Then, an excimer lamp having a center wavelength of 172 nm and a bandwidth of 20 nm was irradiated from above the wafer to the entire surface of the wafer. (P13) Under nitrogen atmosphere (oxygen concentration 1,000ppm)
In was irradiated with F ₂ laser from the wafer top over the whole surface of the wafer.

After the oxidation treatment, the atomic ratio of oxygen to silicon in each region of the organic silicon film (O / Si = the atomic number of oxygen / the atomic number of silicon) and the atomic ratio of carbon to silicon (C / Si = Number of carbon atoms / number of silicon atoms) was measured using X-ray photoelectron spectroscopy. In addition,
Each region of the organic silicon film is a resist pattern 124
(Covered area) 122b and the area (exposed area) 1 not covered with the resist pattern 118
22a.

Table 8 summarizes the atomic ratio in each region together with the atomic ratio in the organic silicon film before the oxidation treatment.

[0316]

[Table 8]

[0317] As shown in Table 8, in the exposed region 122a of the organic silicon film, the amount of oxygen increases, the amount of carbon decreases, and oxidation proceeds. On the other hand, in the organic silicon film covered region 122b, the uncoated region 122a
Compared with, the oxygen and carbon contents did not change and oxidation did not proceed. It is considered that such selective oxidation is due to the following reasons. That is, the resist material used in this embodiment is the same as the resist materials (P11) to (P13)
This is because ultraviolet light in the wavelength range described above is not transmitted.

When the resist pattern 124 before and after the oxidizing treatment was observed using a scanning electron microscope, no reduction in the resist pattern film due to the oxidizing treatment and no deformation of the resist pattern were observed.

Next, the oxidized portion 122a of the organic silicon film is formed using a magnetron type reactive ion etching apparatus.
And the TEOS oxide film 121, which is a film to be processed, were collectively etched. Etching conditions are source gas C ₄ F
₈ / CO / Ar = 20/100/100 SCCM, the degree of vacuum was 75 mTorr, the excitation power density was 1.0 W / cm ² , and the substrate temperature was 40 ° C.

As a result, in any combination, as shown in FIG. 8B, the processed film 121 could be processed with good anisotropy.

Next, in order to examine the dimensional conversion difference caused by the processing, the dimensions of the resist pattern 124 formed on the organic silicon film 122 (defined by X ₂ in FIG. 7C) and
The difference (= Z ₂ −X ₂ ) from the dimension (defined by Z ₂ in FIG. 8B) of the film pattern 121b to be processed was measured. Table 8 summarizes the measurement results of the dimensional conversion difference.

As shown in Table 8, in each case, the tolerance was 7.5 nm or less (5% of the processing size).
The resist pattern 124 was transferred to the film 121 with good controllability.

Further, the etching of the oxidized portion of the organic silicon film 122 is stopped halfway, and the shaved amount of the resist pattern 124 and the shaved amount of the oxidized portion 122a of the organic silicon film are measured to select the resist for the organic silicon film with respect to the resist. The ratio was determined. The results obtained are summarized in Table 8 above. As shown in Table 8, in each case, the aforementioned (Example II-1)
The lower layer film is etched at a high selectivity of 3 or more as in the case of (1). As a result, the retreat of the resist pattern 124 due to the etching of the organic silicon film 122 could be suppressed, and the film 121 to be processed could be processed with good dimensional control. (Embodiment III) In this embodiment, a fourth pattern forming method will be described. (Embodiment III-1) This embodiment will be described below with reference to FIGS.

First, a compound [PSO-5] (R ⁶¹ , R ⁶¹ ) having a weight average molecular weight of 8,000 as an organosilicon compound
⁶² , R ⁶³ = CH ₃ ) was dissolved in 90 g of methyl isobutyl ketone to prepare a solution material for the organic silicon film. After applying this solution material on the silicon wafer 200 by the spin coating method, 350
At 30 ° C. for 30 minutes to form a film having a film thickness of 5 as shown in FIG.
A 00 nm organic silicon film 201 was formed.

Next, 10 g of polysulfone was dissolved in 90 g of cyclohexanone to prepare a solution material for the lower layer film.
This solution material is applied onto the organic silicon film 201 by a spin coating method, and then applied to a hot plate using a hot plate.
By heating at 0 ° C. for 90 seconds, a lower layer 202 having a thickness of 40 nm as shown in FIG. 4B was formed.

A resist solution was applied onto the obtained lower layer film 202 by spin coating, and baked on a hot plate at 100 ° C. for 90 seconds to obtain a resist solution shown in FIG.
A resist film 203 was formed as shown in FIG. The resist solution used here had a weight average molecular weight of 12,000.
8. A dissolution inhibitor resin in which 40% of the hydroxyl groups of the polyvinyl phenol are protected with tertiary butoxycarboxyl groups.
9 g and a positive chemically amplified resist obtained by dissolving 9 g of sulfonimide as an acid generator in 90 g of ethyl lactate.

The thickness of the formed resist film 203 is 20
0 nm.

Next, the resist film 203 was subjected to pattern exposure using a reduction optical type stepper using a KrF excimer laser as a light source, and was baked at 100 ° C. for 90 seconds using a hot plate. By subjecting the baked resist film 203 to a development process using 0.21 N tetramethylammonium hydroxide, a diameter of 0.15 μm as shown in FIG.
The contact hole pattern 204 was formed.

Using the obtained resist pattern 204 as an etching mask, the lower film 202 was etched by a magnetron-type reactive ion etching apparatus to form a lower film pattern 207 as shown in FIG. The etching conditions at this time are as follows: source gas C ₄ F ₈ /
CO / Ar = 20/100/100 SCCM, vacuum degree 7
5 mTorr, an excitation power density of 1.0 W / cm ² , and a substrate temperature of 40 ° C.

Subsequently, as shown in FIG. 5B, the ArF excimer laser 208 was irradiated in a nitrogen atmosphere (oxygen concentration 1,0).
(00 ppm), the organic silicon film 201 was oxidized by irradiating the entire surface of the wafer. Observation of the resist pattern 204 before and after the oxidation treatment using a scanning electron microscope showed that the oxidation treatment did not reduce the thickness of the resist pattern or did not deform the pattern.

Further, in each region of the organic silicon film after the oxidation treatment, the atomic ratio of oxygen to silicon (O / O
Si = number of oxygen atoms / number of silicon atoms) and the ratio of carbon to silicon atoms (C / Si = number of carbon atoms / number of silicon atoms) were measured using X-ray photoelectron spectroscopy. Each region of the organic silicon film is a region (covered region) 201 covered with the resist pattern 204 or the like.
b and an area 201a (exposed area) 201a not covered with the resist pattern 204 or the like.

The ratio of the number of atoms in each region was determined by the oxidation treatment (A
Table 9 below shows the atomic ratios in the organic silicon film before (irradiation with rF excimer laser).

[0333]

[Table 9]

As shown in Table 9, in the exposed portion 201a of the organic silicon film, the ratio of oxygen atoms to silicon (O / Si) was increased by irradiation with ArF excimer laser, and the ratio of carbon atoms to silicon (C / Si) has been reduced, indicating that decarbonization is in progress. On the other hand, decarbonization has not progressed in the organic silicon film covering region 201b. This is considered for the following reasons. That is, the resist film 2 formed in this embodiment is
03 and the lower film 202 both have a low transmittance of 0.1% per μm at a wavelength of 193 nm.
For this reason, when irradiating ArF excimer laser,
This is because the resist pattern 204 and the lower layer pattern 207 acted as a photomask, and no cutting reaction between silicon and organic groups occurred in the organic silicon film covering region 201b.

When the covering region 201b of the organic silicon film is not oxidized in this way, an organic silicon film pattern can be obtained without increasing the dielectric constant.

Next, the organic silicon film was etched using a magnetron-type reactive ion etching apparatus.
Organic silicon film pattern 201 as shown in FIG.
b was formed. The etching conditions are as follows: source gas source gas C ₄ F ₈ / CO / Ar = 20/100 / 100SCC
M, degree of vacuum 75 mTorr, excitation power density 1.0 W / c
m ² , and the substrate temperature was 40 ° C. As a result, as shown in FIG. 5C, the organic silicon film 201 could be processed with good anisotropy in any of the organic silicon films.

Next, the organic silicon film 2 is etched.
To investigate the pattern shift occurring in 01, the opening diameter of the before etching resist pattern 204 formed on the organic silicon film 201 (defined by X ₃ in FIG. 4 (d)), open an organic silicon film pattern 201b Hole diameter (Y _{3 in} FIG. 5 (c))
) (= Y ₃ −X ₃ ). Dimension conversion difference is 6.5 nm, which is an allowable range (5% of the processing size) at 5 nm.
The resist pattern 204 was transferred to the organic silicon film 201 with good controllability.

Also, the etching of the oxidized portion of the organic silicon film 201 is stopped halfway, and the shaved amount of the resist pattern 204 and the shaved amount of the oxidized portion 201a of the organic silicon film are measured to determine a resist selectivity (= organic silicon Calculation of (film etching rate / resist pattern etching rate) was as excellent as 4.2, indicating that etching was performed at a high selectivity. As a result, the organic silicon film was processed anisotropically with good dimensional control, and the organic silicon film pattern 201b was obtained. (Comparative Example III-1) Etching of a silicon film was attempted in the same manner as in (Example III-1) described above, except that the oxidation treatment was not performed on the organic silicon film.

First, in the same manner as in (Example III-1),
An organic silicon film 201, a lower layer film 202, and a resist pattern 204 were sequentially formed on a silicon wafer 200.

Next, when an attempt was made to etch the organic silicon film 201 under the same etching conditions as described above, the resist pattern 204 was not completely removed during the etching of the organic silicon film.
01 could not be processed to the desired dimensions. When the etching of the organic silicon film was stopped halfway and the selectivity of the organic silicon film to the resist was examined, it was only 0.7.

From the results of this comparative example, it can be seen that the organic silicon film 20
It can be seen that in order to improve the selectivity ratio of resist to 1, the exposed region of the organic silicon film 201 (the region covered with the resist pattern or the like) needs to be oxidized. (Comparative Example III-2) First, in the same manner as in (Example III-1), the organic silicon film 201 and the lower film 2 were processed.
02 and a resist pattern 204 were sequentially formed on the silicon wafer 200.

Next, using a plasma ashing apparatus,
The organic silicon film 201 was subjected to oxygen plasma treatment. The parameters of source gas, excitation power density and substrate density are O ₂ = 1000 SCCM, 1.2 W / cm ² , 12
It was kept constant at 0 ° C. The degree of vacuum is 10, 30, 50, 70,
Oxygen plasma treatment was performed with five changes at 90 mTorr, and the film thickness of the resist pattern 204 reduced by oxygen plasma was examined.

In addition, the organic silicon film 201 was formed as in Example I.
Etching was performed in the same manner as in II-1), and the selectivity to resist was examined. Table 10 shows the measurement results.

[0344]

[Table 10]

As shown in Table 10, when the degree of vacuum is reduced, the amount of oxygen radicals is reduced, so that the resist pattern 204 is less likely to be ashed, and the film thickness of the pattern is also reduced. However, the organic silicon film 201
Is hardly oxidized, so that it is difficult to obtain a selective ratio with respect to the resist. On the other hand, when the degree of vacuum is increased, the amount of oxygen radicals is increased, so that the organic silicon film 201 is easily oxidized and the resist selectivity is improved, but the resist pattern 204 is easily ashed. In this case, the thickness of the resist pattern is significantly reduced.

That is, when the oxygen plasma treatment is used to oxidize the organic silicon film 201, it is found that the reduction in the film thickness of the resist pattern 204 cannot be suppressed and the selectivity with respect to the resist cannot be increased. (Example III-2) First, by the same method as in (Example III-1), as shown in FIG.
01 and the lower film 202 were formed on the silicon wafer 200.

A resist solution was applied on the obtained lower layer film 202 by spin coating, and baked on a hot plate at 140 ° C. for 90 seconds to obtain a resist solution shown in FIG.
A resist film 203 was formed as shown in FIG. The resist solution used here had a weight average molecular weight of 18,000.
[P-1] as dissolution inhibitor resin of 9.9 g
And 0.1 g of a compound [P-2] as an acid generator dissolved in 90 g of ethyl lactate. The compounds used are the same as those already described in the above (Example II-1).

The thickness of the obtained resist film 203 is 200
nm.

Next, the resist film 203 was subjected to pattern exposure using a reduction optical stepper using an ArF excimer laser as a light source, and then baked at 140 ° C. for 90 seconds using a hot plate. By subjecting the baked resist film 203 to development processing using 0.26 N tetramethylammonium hydroxide, a contact hole pattern 204 having a diameter of 0.13 μm was formed.

Next, the lower film 202 is etched by the same method as in (Example III-1) to form a lower film pattern 207 as shown in FIG. 5A, and as shown in FIG. Was irradiated with ultraviolet light 208 to oxidize the exposed region 201a of the organic silicon film. As a result, as in the case of (Example III-1), the oxidation does not progress in the organic silicon film covered region (the region covered with the resist pattern 204 and the like) 201b, and the exposed portion of the organic silicon film (the resist Only the region (not covered by the pattern 204) 201b) could be selectively oxidized. It is considered that such selective oxidation is due to the following reasons. That is, the resist material used in the present example is 1 μm in the wavelength region of the ArF excimer laser.
Although the transmittance per m is as high as 84.55%, the transmittance of the lower layer film is as low as 0.1%. For this reason, at the time of irradiation with the ArF excimer laser, the lower layer film pattern 207 acted as a photoresist, and it was possible to selectively oxidize only the area not covered with the resist pattern 204.

From the results of this example, it can be seen that the organic silicon film covered region (the region covered with the resist pattern 204) 2
01b, the resist pattern 20
It can be seen that it is only necessary that any one of No. 4 and the lower film pattern 207 function as a photomask for ultraviolet light irradiated during oxidation.

Next, when the organic silicon film was etched, it was possible to process the organic silicon film with a high selectivity to the resist pattern 204 in the same manner as in (Example III-1). The organic silicon film could be processed anisotropically.

[0353]

As described in detail above, according to the present invention,
In the method of patterning the lower layer film, it is possible to form a pattern having a good shape with a rectangular side wall and a rectangular cross section with high resolution and high dimensional accuracy, while suppressing reduction in the thickness of the resist pattern in the upper layer. A method for forming a pattern is provided.

Further, according to the present invention, there is provided a pattern forming method using an organosilicon film as an antireflection film which can be etched quickly with respect to a resist pattern and can be formed by a spin coating method. Further, according to the present invention, there is provided a pattern forming method capable of improving the selectivity to resist when processing an organic silicon film using a resist pattern as an etching mask and processing the organic silicon film with good dimensional control.

The present invention is extremely effectively used for microfabrication for manufacturing a semiconductor device, and its industrial value is enormous.

[Brief description of the drawings]

FIG. 1 is a process sectional view illustrating an example of a pattern forming method of the present invention.

FIG. 2 is a process sectional view showing another example of the pattern forming method of the present invention.

FIG. 3 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 4 is a process sectional view showing another example of the pattern forming method of the present invention.

FIG. 5 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 6 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 7 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 8 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 9 is a schematic diagram showing a cross-sectional shape of a pattern formed by a conventional pattern forming method.

FIG. 10 is a schematic diagram showing a cross-sectional shape of a pattern formed by a conventional pattern forming method.

[Description of Signs] 10, 20, 30, 110, 120, 200: Silicon wafer 11: Film to be processed 12, 116, 122, 201: Organic silicon film 13, 117, 123, 203: Resist film 13b, 23, 33 , 118, 124 ... resist pattern 14 ... exposure light 15 ... oxygen source 21, 31 ... workpiece film 22 ... underlayer film 24 ... footing 32, 35 ... underlayer film pattern 34 ... residual layer 111 ... SiO ₂ film 112 ... TiN film 113 ... Ti film 114 ... 0.5% -Cu-Al film 115 ... Metal wiring layer 119,125 ... UV light 121 ... TEOS oxide film 202 ... Lower film 204 ... Contact hole pattern 207 ... Lower film pattern 208 ... ArF excimer laser

Continued on the front page F term (reference) 2H025 AA02 AA03 AB16 AC01 AC04 AC06 AC08 AD01 AD03 CB17 CB29 CB41 CC17 DA13 DA14 DA29 DA34 DA40 FA17 FA39 FA41 2H096 AA25 BA06 BA11 CA01 CA02 CA06 CA20 EA02 EA05 EA06 GA08 HA15 HA24 HA24

Claims (6)

[Claims] A step of forming an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain on a film to be processed; a step of forming a resist pattern on the organic silicon film; A step of selectively oxidizing an exposed portion of the organic silicon film using the resist pattern as a mask, and a step of dissolving and removing the oxidized portion of the organic silicon film in an atmosphere containing fluorine. Pattern formation method. 2. The pattern forming method according to claim 1, further comprising, prior to the step of forming an organic silicon film on the film to be processed, a step of forming a fluorine-resistant thin film on the film to be processed. A step of forming an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain on the film to be processed; a step of forming a resist pattern on the organic silicon film; A pattern forming method comprising: selectively oxidizing an exposed portion of an organic silicon film using the resist pattern as a mask; and dissolving and removing an oxidized portion of the organic silicon film with an alkaline aqueous solution. . 4. The pattern forming method according to claim 1, wherein the oxidation treatment is performed by irradiating an energy beam, oxygen radicals, or ozone. 5. a step of forming an organic silicon film containing an organic silicon compound having a bond between silicon and silicon in a main chain on a film to be processed; a step of forming a resist pattern on the organic silicon film; Using the resist pattern as a mask, oxidizing the exposed portion of the organic silicon film by at least one of ultraviolet irradiation and heating, and dry-etching the oxidized portion of the organic silicon film using a fluorine-based gas. A pattern forming method comprising a step of removing by a method. 6. a step of forming an organic silicon film containing an organic silicon compound having a bond between silicon and oxygen in a main chain on a film to be processed; a step of forming a resist pattern on the organic silicon film; Using the resist pattern as a mask, a step of selectively decarbonizing the exposed portion of the organic silicon film by irradiating ultraviolet rays, and the decarbonized portion of the organic silicon film is treated with a fluorine-based gas. A pattern forming method comprising a step of removing by used dry etching.