KR20100009506A - Composition for forming lower layer film - Google Patents

Abstract

PURPOSE: A composition for forming a lower layer film is provided to ensure low amount of sublimated material, excellent etching resistance, and good refraction index and decay coefficient. CONSTITUTION: A composition for forming a lower layer film comprises (A) a polymer having a structure unit represented by chemical formula 1, a structure unit represented by chemical formula 2, a structure unit represented by chemical formula 3, and a structure unit represented by chemical formula 4; (B) a cross-linking agent having a butyl ether group; and (C) solvent.

Description

Underlayer film forming composition {COMPOSITION FOR FORMING LOWER LAYER FILM}

The present invention relates to an underlayer film forming composition. More specifically, the present invention relates to an underlayer film forming composition capable of forming an underlayer film having excellent embedding properties, low sublimation amount, and excellent etching resistance and good values of refractive index and decay coefficient.

The manufacturing process of a semiconductor device includes the process of depositing a some substance as a to-be-processed film on a silicon wafer, and forming (patterning) a desired pattern in this to-be-processed film, respectively. Specifically, in the patterning, first, a resist (photosensitive material) is deposited on the processing film to form a resist film, and exposure is performed on a predetermined region of the resist film. Next, the exposed portion or unexposed portion of the resist film is removed by a developing process to form a resist pattern. Thereafter, the processed film is dry etched using this resist pattern as an etching mask.

In such a process, ultraviolet light, such as an ArF excimer laser, is used as an exposure light source for exposing to a resist film. At present, there is an increasing demand for miniaturization of large-scale integrated circuits (LSI), and sometimes the required resolution becomes less than the wavelength of exposure light. When the resolution becomes less than the wavelength of exposure light in this manner, the exposure process margins such as the exposure margin and the focus margin are insufficient. In order to make up for the lack of the exposure process margin, it is effective to reduce the film thickness of the resist film to improve the resolution. On the other hand, it becomes difficult to secure the resist film thickness required for etching the process film.

In this regard, a resist underlayer film (hereinafter simply referred to as "underlayer film") is formed on the processed film, and the resist pattern is once transferred to the underlayer film to form an underlayer film pattern. The process (also called a multilayer process) which transfers to a to-be-processed film using as an etching mask is examined. In such a step, it is preferable that the underlayer film contains a material having etching resistance. For example, as a material which forms such an underlayer film, the composition etc. which absorb the energy in etching and contain the polymer which has an acenaphthylene skeleton known to be etch resistant are proposed (for example, patent documents 1-5). Reference).

By the way, when the LSI pattern rule of 0.13 µm or less becomes fine, the influence that the wiring delay provides for the high speed of the LSI increases, and it is difficult to advance the high performance of the LSI by the current LSI process technology. Therefore, Cu is known as one of the materials (wiring materials) used in order to reduce wiring delay. And the technique introduced in order to change wiring material from Al to Cu is a dual damascene process (for example, refer patent document 6). In this dual damascene process, an underlayer film is formed on a substrate that is finer and has a larger aspect ratio (concave-convex) than the substrate of the conventional wiring material Al.

Here, although the underlayer film forming composition of patent documents 1-4 has the favorable etching tolerance and reflection prevention function peculiar to the acenaphthylene skeleton, the board | substrate which is fine and has a large aspect ratio cannot fully be embedded.

Therefore, it is reported that the molecular weight of the polymer (polymer having an acenaphthylene skeleton) in the underlayer film forming composition is 2000 or less as a method of embedding on a substrate having a large aspect ratio, that is, a method of improving embedding properties ( See patent document 5). Moreover, in patent document 7, it is reported that the molecular weight of the polymer in underlayer film forming composition is 3000 or less.

<Patent Document 1> Japanese Patent Application Laid-Open No. 2000-143937

<Patent Document 2> Japanese Patent Application Laid-Open No. 2001-40293

<Patent Document 3> Japanese Unexamined Patent Application Publication No. 2004-168748

<Patent Document 4> Japanese Patent Application Laid-Open No. 2005-250434

<Patent Document 5> Japanese Patent Application Laid-Open No. 2005-15532

<Patent Document 6> US Patent No. 6057239

Patent Document 7: Japanese Unexamined Patent Publication No. 2000-294504

However, when the molecular weight of the polymer in the underlayer film-forming composition, in particular, the polymer having an acenaphthylene skeleton, is reduced, the low-molecular component and its decomposition product in the polymer may sublimate when the underlayer film is formed by the underlayer film-forming composition. Thus, when the low molecular weight component or its decomposition product sublimes (that is, when a sublimation occurs), there exists a problem that the apparatus for forming an underlayer film becomes contaminated.

Thus, when the molecular weight of a polymer was reduced for the purpose of improving the embedding property of an underlayer film forming composition, there existed a problem that the amount of a sublimation will increase. Therefore, in addition to being excellent in embedding properties for substrates having a large aspect ratio, development of an underlayer film-forming composition in which the amount of sublimation generated when forming an underlayer film is reduced is desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above. In addition to being excellent in embedding properties and having a small amount of sublimation, an underlayer film having excellent etching resistance and good values of refractive index and decay coefficient is formed. It is providing the underlayer film forming composition which can be performed.

By the present invention, the following underlayer film forming compositions are provided.

[1] (A) A polymer having a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4), and (B) An underlayer film formation composition containing the crosslinking agent which has a butyl ether group, and (C) solvent.

(However, in formula (1), R ¹ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, 1 to C carbon 6 alkoxycarbonyloxy group, methylol group, or alkoxymethylol group having 1 to 6 carbon atoms, R ² and R ³ each represent a hydrogen atom or an alkyl group which may be substituted with 1 to 6 carbon atoms)

(However, in formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkylene group having 1 to 4 carbon atoms)

(However, in the above formula (3), R ⁶ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, 1 to C carbon 6 represents an alkoxycarbonyloxy group, a methylol group, or an alkoxymethylol group having 1 to 6 carbon atoms, R ⁷ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 3 Indicates)

(However, in Formula 4, R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, optionally substituted alkyl group of 1 to 6 carbon atoms)

[2] The underlayer film forming composition according to the above [1], wherein a weight average molecular weight (Mw) in terms of polystyrene of the polymer (A) is 500 to 10,000.

[3] The underlayer film forming composition according to the above [1] or [2], wherein the (B) crosslinking agent is a compound represented by the following Formula (5) or (6).

(However, in Formula 5, R ¹¹ each independently represent a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that four R ¹¹ Two or more of which are n-butyl or iso-butyl)

(However, in Formula 6, R ¹² independently represents a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that at least two of six R ¹² is n-butyl group or iso- Butyl)

[4] The ratio of the structural units represented by the general formula (1) contained in the polymer (A) to any one of the above [1] to [3] to 100 mol% of the total structural units of the polymer (A). It is 5-80 mol%, and the ratio of the structural unit represented by the said General formula (2) contained in the said (A) polymer is 5-80 mol% with respect to 100 mol% of all the structural units of the said (A) polymer, The said (A The underlayer film forming composition whose ratio of the structural unit represented by the said Formula (3) contained in a polymer is 0.1-50 mol% with respect to 100 mol% of all the structural units of the said (A) polymer.

[5] The underlayer film forming composition according to any one of the above [1] to [4], further comprising (D) an acid generator.

The underlayer film-forming composition of the present invention exhibits an effect of being able to form an underlayer film having excellent embedding properties, low sublimation amount, excellent etching resistance, and good values of refractive index and decay coefficient.

EMBODIMENT OF THE INVENTION Hereinafter, although the best form for implementing this invention is demonstrated, this invention is not limited to the following embodiment. In other words, it should be understood that modifications, improvements, and the like to the following embodiments are appropriately applied to the following embodiments based on common knowledge of those skilled in the art without departing from the spirit of the present invention.

[1] an underlayer film forming composition:

One embodiment of the underlayer film forming composition of the present invention is (A) a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structure represented by the following formula (4) It contains the polymer which has a unit, the crosslinking agent which has (B) butyl ether group, and (C) solvent. Such an underlayer film-forming composition can form an underlayer film that is excellent in embedding properties, has a small amount of sublimation, is excellent in etching resistance, and has good values of refractive index and decay coefficient.

<Formula 1>

(However, in formula (1), R ¹ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, 1 to C carbon 6 alkoxycarbonyloxy group, methylol group, or alkoxymethylol group having 1 to 6 carbon atoms, R ² and R ³ each represent a hydrogen atom or an alkyl group which may be substituted with 1 to 6 carbon atoms)

<Formula 2>

(However, in formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkylene group having 1 to 4 carbon atoms)

<Formula 3>

(However, in the above formula (3), R ⁶ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, 1 to C carbon 6 represents an alkoxycarbonyloxy group, a methylol group, or an alkoxymethylol group having 1 to 6 carbon atoms, R ⁷ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 3 Indicates)

<Formula 4>

(However, in Formula 4, R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, optionally substituted alkyl group of 1 to 6 carbon atoms)

[1-1] (A) Polymer:

The (A) polymer which the underlayer film forming composition of this embodiment contains is represented by the structural unit represented by General formula (1), hereafter described as "structural unit (1)", and the structural unit represented by General formula (2) The structural unit represented by "structural unit (2)" may be described, the structural unit represented by general formula (3) (hereinafter may be described as "structural unit (3)"), and the structural unit represented by general formula (4) Structural unit (4) ”). By containing such a polymer, since the main chain which contains many aliphatic, the aliphatic in a structural unit, and the ester group of a terminal improve the flexibility of the whole resin, there exists an advantage that the embedding | bubble to a small diameter via and a trench is especially favorable.

[1-1-1] The structural unit represented by formula (1):

Since the polymer (A) contains the structural unit represented by the formula (1), the underlayer film forming composition of the present embodiment can form an underlayer film excellent in etching resistance.

In the general formula (1), examples of the alkoxyl group having 1 to 6 carbon atoms for R ¹ include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 1-methylpropoxy group, 2 -Methyl propoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, etc. are mentioned.

Examples of the alkoxycarbonyl group having 1 to 6 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, i-propoxycarbonyl group, n-butoxycarbonyl group, 1-methylpropoxycarbonyl group, and 2-methylpropoxy. Carbonyl group, tert-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group, etc. are mentioned.

Examples of the alkoxycarbonyloxy group having 1 to 6 carbon atoms include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, and n-part. Oxycarbonyloxy group, 1-methylpropoxycarbonyloxy group, 2-methylpropoxycarbonyloxy group, tert-butoxycarbonyloxy group, n-pentyloxycarbonyloxy group, n-hexyloxycarbono And a silyloxy group.

Examples of the alkoxy methylol group having 1 to 6 carbon atoms include methoxymethylol group, ethoxymethylol group, n-propoxymethylol group, i-propoxymethylol group, n-butoxymethylol group, 1-methylpropoxymethyl Ol group, 2-methylpropoxymethylol group, tert-butoxymethylol group, n-pentyloxymethylol group, n-hexyloxymethylol group, etc. are mentioned.

In the formula (1), examples of the alkyl group which may be substituted with 1 to 6 carbon atoms of R ² and R ³ include methyl group, butyl group, hexyl group and the like. Among these, a methyl group is preferable.

As a monomer which provides the structural unit represented by such General formula (1), for example, acenaphthylene, 3-hydroxymethylacenaphthylene, 4-hydroxymethylacenaphthylene, 5-hydroxymethylacenaphthylene, 1- Methyl-3-hydroxymethylacenaphthylene, 1-methyl-4-hydroxymethylacenaphthylene, 1-methyl-5-hydroxymethylacenaphthylene, 1-methyl-6-hydroxymethylacenaphthylene, 1-methyl-7-hydroxymethylacenaphthylene, 1-methyl-8-hydroxymethylacenaphthylene, 1,2-dimethyl-3-hydroxymethylacenaphthylene, 1,2-dimethyl-4-hydroxy Hydroxymethylacenaphthylene, 1,2-dimethyl-5-hydroxymethylacenaphthylene, 1-phenyl-3-hydroxymethylacenaphthyleneacenaphthylene, 1-phenyl-4-hydroxymethylacenaphthyleneace Naphthylene,

1-phenyl-5-hydroxymethylacenaphthyleneacenaphthylene, 1-phenyl-6-hydroxymethylacenaphthyleneacenaphthylene, 1-phenyl-7-hydroxymethylacenaphthylene, 1-phenyl-8 -Hydroxymethylacenaphthyleneacenaphthylene, 1,2-diphenyl-3-hydroxymethylacenaphthylene, 1,2-diphenyl-4-hydroxymethylacenaphthylene, 1,2-diphenyl- Hydroxymethylacenaphthylenes such as 5-hydroxymethylacenaphthylene;

3-methoxymethylacenaphthylene, 4-methoxymethylacenaphthylene, 5-methoxymethylacenaphthylene, 1-methyl-3-methoxymethylacenaphthylene, 1-methyl-4-methoxymethylace Naphthylene, 1-methyl-5-methoxymethylacenaphthylene, 1-methyl-6-methoxymethylacenaphthylene, 1-methyl-7-methoxymethylacenaphthylene, 1-methyl-8-methoxy Methylacenaphthylene, 1,2-dimethyl-3-methoxymethylacenaphthylene, 1,2-dimethyl-4-methoxymethylacenaphthylene, 1,2-dimethyl-5-methoxymethylacenaphthylene, 1-phenyl-3-methoxymethylacenaphthylene,

1-phenyl-4-methoxymethylacenaphthylene, 1-phenyl-5-methoxymethylacenaphthylene, 1-phenyl-6-methoxymethylacenaphthylene, 1-phenyl-7-methoxymethylacenaphate Methylene, 1-phenyl-8-methoxy methylacenaphthylene, 1,2-diphenyl-3-methoxymethylacenaphthylene, 1,2-diphenyl-4-methoxymethylacenaphthylene, 1,2 Methoxymethylacenaphthylenes such as diphenyl-5-methoxymethylacenaphthylene;

3-phenoxymethylacenaphthylene, 4-phenoxymethylacenaphthylene, 5-phenoxymethylacenaphthylene, 3-vinyloxymethylacenaphthylene, 4-vinyloxymethylacenaphthylene, 5-vinyloxymethyl Acenaphthylene, 3-acetoxymethylacenaphthylene, 4-acetoxymethylacenaphthylene, 5-acetoxymethylacenaphthylene and the like. In addition, these monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these, acenaphthylene, 3-hydroxymethylacenaphthylene, 4-hydroxymethylacenaphthylene, 5-hydroxymethylacenaphthylene, 3-methoxymethylacenaphthylene, 4-methoxymethylacenaph Pylene and 5-methoxymethylacenaphthylene are preferred.

It is preferable that the ratio of the structural unit represented by General formula (1) contained in (A) polymer is 5-80 mol% with respect to 100 mol% of all the structural units of (A) polymer, It is more preferable that it is 30-80 mol% It is especially preferable that they are 50-70 mol%. When the said ratio is less than 5 mol%, since etching resistance falls, there exists a possibility that pattern transfer at the time of an etching may become impossible. On the other hand, when it exceeds 80 mol%, since antireflection function falls, there exists a possibility that the pattern formation ability in a lithography technique may not fully be obtained.

[1-1-2] The structural unit represented by formula (2):

Since the polymer (A) contains the structural unit represented by the formula (2), the glass transition temperature of the polymer (A) is lowered, flexibility is provided, and a composition having good embedding properties with respect to a large aspect ratio substrate is obtained. Moreover, the characteristic which produces a crosslinking reaction between molecular chains by heating or exposure is obtained, and it becomes possible to control the crosslinking degree (hardening degree) of a polymer (A), and can prevent intermixing.

In the formula (2), examples of the alkylene group having 2 to 4 carbon atoms for R ⁵ include ethylene group, propylene group, i-propylene group, butylene group, i-butylene group and the like.

As a monomer which provides the structural unit represented by such a formula (2), 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, for example Can be mentioned. In addition, these monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that the ratio of the structural unit represented by General formula (2) contained in (A) polymer is 5-80 mol% with respect to 100 mol% of all the structural units of (A) polymer, It is more preferable that it is 5-60 mol% It is especially preferable that it is 5-50 mol%. When the said ratio is less than 5 mol%, since a crosslinked structure becomes difficult to fully form, it may cause intermixing with an intermediate | middle layer at the time of intermediate | middle film forming, and there exists a possibility that etching selectivity may fall. On the other hand, when it exceeds 80 mol%, since etching resistance falls, there exists a possibility that pattern transfer by an etching may not be possible.

[1-1-3] The structural unit represented by formula (3):

(A) By containing a structural unit represented by General formula (3), a polymer can adjust the reflectance of the underlayer film formed. Specifically, when the content ratio of the structural unit (3) is increased, the attenuation coefficient (k value) in the ArF wavelength can be increased.

R <^6> in Formula (3) can illustrate the same thing as R <^1> in Formula (1). An alkyl group which may be substituted with 1 to 6 carbon atoms of R ⁷ in Formula 3 may be the same as R ² or an alkyl group which may be substituted with 1 to 6 carbon atoms of R ³ in Formula 1.

As a monomer which provides the structural unit represented by such a formula (3), for example, styrene, hydroxy styrene, tert-butoxy styrene, tert-butoxycarbonyloxy styrene, (alpha) -methylstyrene, 4-methylstyrene, 2- Methylstyrene, 3-methylstyrene, 4-methoxystyrene, 4-hydroxymethylstyrene, 3-hydroxymethylstyrene, 4-ethylstyrene, 4-ethoxystyrene, 3,4-dimethylstyrene, 3,4- Diethyl styrene, 2-chlorostyrene, 3-chlorostyrene, 4-chloro-3-methylstyrene, 4-t-butylstyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, etc. are mentioned. In addition, these monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these, styrene, 4-hydroxymethylstyrene, 3-hydroxymethylstyrene, tert-butoxystyrene, and tert-butoxycarbonyloxystyrene are preferable.

It is preferable that the ratio of the structural unit represented by General formula (3) contained in (A) polymer is 0.1-50 mol% with respect to 100 mol% of all the structural units of (A) polymer, It is more preferable that it is 1-30 mol% , 3 to 20 mol% is particularly preferable. If the said ratio is less than 0.1 mol%, since the antireflection function will fall, there exists a possibility that the pattern formation ability in a lithography technique may not be fully acquired. Moreover, even if it exceeds 50 mol%, since the antireflection function falls, there exists a possibility that the pattern formation ability in a lithography technique may not be fully acquired.

[1-1-4] The structural unit represented by formula (4):

In addition to providing flexibility to the resin (polymer (A)) by (A) the polymer containing a structural unit represented by the formula (4), that is, the structural unit (4) is located at the terminal of the polymer (A), A) Since a polymer is hard to decompose | disassemble, a buried property becomes favorable and a low sublimation underlayer film forming composition can be obtained.

The alkyl group optionally substituted with 1 to 6 carbon atoms of R ⁸ , R ⁹ and R ¹⁰ in Formula 4 may be the same as the alkyl group optionally substituted with 1 to 6 carbon atoms of R ² or R ³ in Formula 1.

The structural unit represented by this formula (4) is a structural unit derived from the radical polymerization initiator used when manufacturing a polymer (A). As a commercial item of this radical polymerization initiator, all are brand name, for example, "V-601", "VE-057", "V-501", "VA-057" (above, Wako Pure Chemical Industries Ltd.), etc. are mentioned, for example. . Among these, since it is protected by an ester group, "V-601" is preferable from a viewpoint that the terminal of resin ((A) polymer) is a flexible skeleton.

It is preferable that the ratio of the structural unit represented by General formula (4) contained in (A) polymer is 0.01-50 mol% with respect to 100 mol% of all the structural units of the (A) polymer, It is more preferable that it is 0.1-30 mol% , 1 to 20 mol% is particularly preferable. When the said ratio is less than 0.01 mol%, since flexibility of resin falls, there exists a possibility that embedding property may fall. On the other hand, when it exceeds 50 mol%, since etching resistance falls, there exists a possibility that pattern transfer capability may fall.

[1-1-5] Other structural units:

The polymer (A) may contain other structural units in addition to the structural unit (1), the structural unit (2), the structural unit (3), and the structural unit (4) described above. As a monomer which provides another structural unit, for example, glycidyl methacrylate, vinyl anthracene, vinyl carbazole, vinyl acetate, vinyl propionate, vinyl caproate, (meth) acrylonitrile, α-chloroacrylonitrile , Vinylidene cyanide, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl ( Meth) acrylate, n-hexyl (meth) acrylate, glycidyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, vinyl (meth) acrylate, dimethylvinyl (Meth) acryloyloxymethylsilane, chloroethyl vinyl ether, chlorovinyl acetate, allyl chloroacetate, (meth) acrylamide, crotonic acid amide, etc. are mentioned. Among these, glycidyl methacrylate is preferable.

It is preferable that the ratio of the other structural unit contained in (A) polymer is 1-50 mol% with respect to 100 mol% of all the structural units of (A) polymer.

(A) It is preferable that the weight average molecular weights (Mw) of polystyrene conversion of the polymer are 500-10000, and it is more preferable that it is 1500-5000. When the said weight average molecular weight (Mw) is less than 500, when forming an underlayer film, the amount of the sublimation derived from an underlayer film may increase, and it may contaminate a film-forming apparatus. On the other hand, when it exceeds 10000, there exists a possibility that the embedding property to a board | substrate with a large aspect ratio may deteriorate. Here, in this specification, "weight average molecular weight (Mw) of polystyrene conversion" is a value of the weight average molecular weight of polystyrene conversion measured by the gel permeation chromatography.

In addition, when the weight average molecular weight (Mw) is 1500 to 5000, the amount of the sublimation derived from the underlayer film at the time of forming the underlayer film can be sufficiently suppressed, and the underlayer that can be buried well in a substrate having a high aspect ratio A film forming composition can be obtained.

In order to prepare the polymer (A), for example, first, a monomer providing the structural unit (1), a monomer providing the structural unit (2), a monomer providing the structural unit (3), and other structural units are provided. The monomer component containing the monomer to make is dissolved in a solvent (for example, methyl ethyl ketone, methyl isobutyl ketone, etc.) which can melt | dissolve this monomer component, and a solution is obtained. Next, the monomer (ie, radical polymerization initiator) which provides the structural unit (4) is added to this solution. Next, it heats up to predetermined | prescribed temperature (for example, 50-90 degreeC), superposes | polymerizes for 4 to 8 hours, and a polymerization reaction liquid is obtained. Thereafter, the polymerization reaction liquid is reprecipitated with an organic solvent such as n-heptane or methanol to obtain the polymer (A).

In addition, although the usage-amount of a radical polymerization initiator can be suitably selected according to the (A) polymer which has a desired weight average molecular weight, when obtaining the (A) polymer whose weight average molecular weights are 500-10000, the quantity of all the monomers used for superposition | polymerization (Monomers providing structural units (1), monomers providing structural units (2), monomers providing structural units (3), monomers providing structural units (4), and monomers providing other structural units It is preferable that it is 0.5-30 mass parts with respect to 100 mass parts, It is more preferable that it is 1-20 mass parts, It is especially preferable that it is 3-15 mass parts.

Although the content rate of the (A) polymer contained in the underlayer film forming composition of this embodiment can be suitably selected by the film thickness of the underlayer film formed, it is 5-30 mass% with respect to solid content of an underlayer film forming composition. It is preferable and it is more preferable that it is 8-15 mass%. When the content rate of this (A) polymer is less than 5 mass%, there exists a possibility that the lower layer film which has sufficient film thickness may not be obtained. On the other hand, when it exceeds 30 mass%, the viscosity of an underlayer film forming composition becomes high too much and there exists a possibility that the embedding property to a board | substrate may deteriorate.

In addition, 1 type of (A) polymers contained in the underlayer film forming composition of this embodiment may be contained, and 2 or more types may be contained.

[1-2] (B) crosslinking agent:

The crosslinking agent (B) contained in the underlayer film forming composition of this embodiment has a butyl ether group. This (B) crosslinking agent is a component which generally has the effect | action which prevents halation. By including the (B) crosslinking agent, since the film density of the underlayer film is improved, it is difficult to cause intermixing with the intermediate layer, and there is an advantage that the etching resistance is improved.

Although there is no restriction | limiting in particular as (B) crosslinking agent, It is preferable that it is a compound represented by following formula (5) or (6). If the compound is represented by the above formula (5) or (6), the volatility is lowered, so that there is an advantage that it is difficult to sublime.

<Formula 5>

(However, in formula (5), R ¹¹ each independently represent a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that at least two of four R ¹¹ is n-butyl group or iso- Butyl)

<Formula 6>

(However, in Formula 6, R ¹² independently represents a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that at least two of six R ¹² is n-butyl group or iso- Butyl)

The compound represented by the formula (5) is a sublimation derived from the underlayer film-forming composition because at least two of the four R ^{11 s} are n-butyl groups or iso-butyl groups, and thus the sublimation property of the (B) crosslinking agent is further suppressed. It is possible to prevent the coating device from being contaminated. In addition, since the sublimation of (B) crosslinking agent can be suppressed so that the number of n-butyl groups is large, it is preferable that all four R <^11> is n-butyl groups.

The compound represented by the formula (6) is a sublimation derived from the underlayer film-forming composition because at least two of the six R ^{12 s} are n-butyl or iso-butyl groups, and thus the sublimation of the (B) crosslinking agent is further suppressed. It is possible to prevent the coating device from being contaminated. In addition, since the sublimation of (B) crosslinking agent can be suppressed so that the number of n-butyl groups is large, it is preferable that all six R <^12> is n-butyl group.

It is preferable that it is 1-50 mass parts with respect to 100 mass parts of (A) polymers, and, as for the compounding quantity of (B) crosslinking agent, it is more preferable that it is 5-30 mass parts. If the said compounding quantity is less than 1 mass part, crosslinking performance may deteriorate and there may be a halation in an underlayer film. On the other hand, when it exceeds 50 mass parts, since unreacted (B) crosslinking agent (that is, what did not react with (A) polymer) will remain in an underlayer film, there exists a possibility that the etching resistance of an underlayer film may deteriorate.

The underlayer film forming composition of this embodiment can contain other crosslinking agent components other than (B) crosslinking agent. As another crosslinking agent component, polynuclear phenols, a hardening | curing agent, etc. are mentioned, for example.

Examples of the polynuclear phenols include binuclear phenols such as 4,4'-biphenyldiol, 4,4'-methylene bisphenol, 4,4'-ethylidene bisphenol and bisphenol A; 3, such as 4,4 ', 4 "-methylidene trisphenol and 4,4'-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol Polyphenols, such as nucleus phenols and novolak, etc. are mentioned.

As a hardening | curing agent, 2, 3- tolylene diisocyanate, 2, 4- tolylene diisocyanate, 3, 4- tolylene diisocyanate, 3, 5- tolylene diisocyanate, 4,4'- diphenylmethane diisocyanate, hexa Diisocyanate, such as methylene diisocyanate and 1, 4- cyclohexane diisocyanate, etc. are mentioned.

As a commercial item of a hardening | curing agent, the following are all brand names, for example, Epicoat 812, East 815, East 826, East 828, East 834, East 836, East 871, East 1001, East 1004, East 1007, East 1009, East 1031 ( Above, manufactured by Yucca Shell Epoxy), Araldite 6600, Copper 6700, Copper 6800, Copper 502, Copper 6071, Copper 6084, Copper 6097, Copper 6099 Epoxy compounds such as 333, 661, 644, and 667 (above, manufactured by Dow Chemical); Cymel 300, East 301, East 303, East 350, East 370, East 771, East 325, East 327, East 703, East 712, East 701, East 272, East 202, My Court 506, East 508 (or more, Mitsui Melamine type hardening | curing agents, such as a cyanamide company make); Benzoguanamine type hardening | curing agents, such as Cymel 1123, 1123-10, 1128, Mycoat 102, 105, 106, and 130 (above, Mitsui Cyanamid Co., Ltd. make); Glycoluril hardening | curing agents, such as Cymel 1170, copper 1172 (above, Mitsui cyanamide company make), and Nicalak N-2702 (manufactured by Sanwa Chemical Co., Ltd.), etc. are mentioned.

[1-3] (C) Solvent:

The solvent (C) contained in the underlayer film-forming composition of the present embodiment is not particularly limited as long as it can dissolve the (A) polymer, (B) crosslinking agent, (D) acid generator, and the like. Can be used.

As the solvent (C), for example, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether and ethylene glycol mono-n-butyl ether; Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, and ethylene glycol mono-n-butyl ether acetate; Diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether and diethylene glycol di-n-butyl ether; Triethylene glycol dialkyl ethers such as triethylene glycol dimethyl ether and triethylene glycol diethyl ether;

Propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether and propylene glycol mono-n-butyl ether; Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether and propylene glycol di-n-butyl ether; Propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, and propylene glycol mono-n-butyl ether acetate;

Lactic acid esters such as methyl lactate, ethyl lactate, lactic acid n-propyl, lactic acid i-propyl, lactic acid n-butyl and lactic acid i-butyl; Methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, n-amyl formate, i-amyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-acetic acid Propyl, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, propionic acid n-propyl, propionic acid i-propyl, propionic acid n-butyl, propionic acid i Aliphatic carboxylic acid esters such as -butyl, methyl butyrate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate and i-butyl butyrate;

Ethyl hydroxyacetate, 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, 3- Methyl methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxypropyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3- Other esters such as methoxybutyl propionate, 3-methyl-3-methoxybutylbutyrate, methyl acetoacetate, methyl pyruvate and ethyl pyruvate; Aromatic hydrocarbons such as toluene and xylene; Ketones such as methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, and cyclohexanone; Amides such as N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpyrrolidone; Lactones, such as (gamma) -butyrolactone, etc. are mentioned. In addition, these (C) solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these, ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, and cyclohexanone are preferable.

Although the compounding quantity of (C) solvent can be suitably selected according to the film thickness of the underlayer film formed, etc., it is preferable that it is the range whose solid content concentration of the underlayer film formation composition obtained becomes 0.01-70 mass%, and becomes 0.05-60 mass%. It is more preferable that it is a range, and it is especially preferable that it is a range which becomes 0.1-50 mass%. When the solid content concentration is less than 0.01% by mass, there is a fear that it is difficult to form an underlayer film having a sufficient film thickness. On the other hand, when it exceeds 70 mass%, since a viscosity is too high, there exists a possibility that formation of a film may become difficult.

[1-4] (D) Acid Generators:

The underlayer film forming composition of this embodiment can further contain the (D) acid generator in addition to the (A) polymer, (B) crosslinking agent, and (C) solvent. This acid generator (D) is a component which generates an acid by exposure or heating. When this (D) acid generator is further contained, since the sclerosis | hardenability of an underlayer film improves, there exists an advantage that it becomes easy to form into a film efficiently. In addition, there is an advantage that the amine components such as ammonia are blocked by increasing the acid concentration in the underlayer film.

Examples of the (D) acid generator (hereinafter referred to as "photoacid generator") that generate an acid upon exposure include, for example, diphenyl iodonium trifluoromethanesulfonate and diphenyl iodonium nonafluoro-. n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium-n-dodecylbenzenesulfonate, diphenyliodonium-10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, Diphenyl iodonium hexafluoro antimonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butane Sulfonate, bis (4-t-butylphenyl) iodonium-n-dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodonium-10-camphorsulfonate,

Bis (4-t-butylphenyl) iodonium naphthalenesulfonate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium Nonafluoro-n-butanesulfonate, triphenylsulfonium-n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium-10-camposulfonate, triphenylsulfonium hexafluoroanti Monate, 4-hydroxyphenyl phenylmethylsulfonium-p-toluenesulfonate, 4-hydroxyphenylbenzylmethylsulfonium-p-toluenesulfonate,

Cyclohexyl methyl 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldicyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate , 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4- Cyano-1-naphthyldiethylsulfoniumtrifluoromethanesulfonate, 4-nitro-1-naphthyldimethylsulfoniumtrifluoromethanesulfonate, 4-nitro-1-naphthyldiethylsulfoniumtrifluoromethane Sulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfoniumtrifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonate Phonium trifluoromethanesulfonate, 4-hydroxy- 1-naphthyldiethylsulfonium trifluoromethanesulfonate,

1- (4-hydroxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-methoxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-ethoxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-methoxymethoxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfo Nate, 1- (4-ethoxymethoxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- [4- (1-methoxyethoxy) naphthalen-1-yl] tetrahydro Thiophenium trifluoromethanesulfonate, 1- [4- (2-methoxyethoxy) naphthalen-1-yl] tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-methoxycarbonyl Oxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothiopheniumtriflu Romero burnt sulfonate, 1- (4-n- propoxycarbonyl-oxy-1-yl) methane as a tetrahydrothiophenium iodonium trifluoromethyl sulphonate,

1- (4-i-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydro Thiophenium trifluoromethanesulfonate, 1- (4-t-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- [4- (2-tetrahydro Furanyloxy) naphthalen-1-yl] tetrahydrothiopheniumtrifluoromethanesulfonate, 1- [4- (2-tetrahydrolopyranyloxy) naphthalen-1-yl] tetrahydrothiopheniumtrifluoro Onium salt-based photoacid generation such as romethanesulfonate, 1- (4-benzyloxy) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (naphthylacetomethyl) tetrahydrothiopheniumtrifluoromethanesulfonate Drift;

Halogen-containing compounds such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine and 1-naphthylbis (trichloromethyl) -s-triazine Type photoacid generators; 1,2-naphthoquinone diazide-4-sulfonyl chloride, 1,2-naphthoquinone diazide-5-sulfonyl chloride, 1,2 of 2,3,4,4'-tetrahydroxybenzophenone Diazoketone compound-based photoacid generators such as naphthoquinone diazide-4-sulfonic acid ester or 1,2-naphthoquinone diazide-5-sulfonic acid ester; Sulfone compound-based photoacid generators such as 4-trisfenacyl sulfone, mesitylphenacyl sulfone and bis (phenylsulfonyl) methane; Benzointosylate, tris (trifluoromethanesulfonate) of pyrogallol, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1] hept- Sulfonate compound-based photoacid generation, such as 5-ene-2,3-dicarbodiimide, N-hydroxysuccinimidetrifluoromethanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate Distillation etc. are mentioned.

Among these photoacid generators, diphenyl iodonium trifluoromethanesulfonate, diphenyl iodonium nonafluoro-n-butanesulfonate, diphenyl iodonium pyrenesulfonate, diphenyl iodonium-n- Dodecylbenzenesulfonate, diphenyliodonium-10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4 -t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium-n-dodecylbenzenesulfonate, bis (4-t-butylphenyl) io Donium-10-camphorsulfonate and bis (4-t-butylphenyl) iodonium naphthalenesulfonate are preferable. In addition, these photo-acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the (D) acid generator (hereinafter referred to as a "thermal acid generator") that generate an acid by heating include 2,4,4,6-tetrabromocyclohexadienone, benzointosylate, 2-nitrobenzyl tosylate, alkyl sulfonates, etc. are mentioned. In addition, these thermal acid generators may be used alone, or may be used in combination of two or more thereof. Moreover, a photo-acid generator and a thermal acid generator can also be used together.

(D) It is preferable that the compounding quantity of an acid generator is 100 mass parts or less with respect to 100 mass parts of (A) polymers, It is more preferable that it is 0.1-30 mass parts, It is especially preferable that it is 0.1-10 mass parts, 0.5-10 Most preferably, it is mass part. When the said compounding quantity is less than 0.1 mass part, acid does not generate | occur | produce sufficiently in an underlayer film, and there exists a possibility that the sclerosis | hardenability of a film may be impaired. Moreover, there exists a possibility that it may become impossible to fully prevent an amine component from diffusing into a resist film by trapping amine components, such as ammonia which inhibits the chemical reaction of the resist forming composition. On the other hand, when it exceeds 30 mass parts, the excess acid which generate | occur | produced in the lower layer film diffuses in a resist film, and there exists a possibility that the shape of a resist film may deteriorate. Moreover, when forming an underlayer film, the decomposition product of the (D) acid generator becomes a sublimate, and there exists a possibility of contaminating a coating film-forming apparatus.

[1-5] Other additives:

The underlayer film forming composition of this embodiment can contain other additives other than (A) polymer, (B) crosslinking agent, (C) solvent, and (D) acid generator. As another additive, a thermosetting resin, a radiation absorber, surfactant, a storage stabilizer, an antifoamer, an adhesion | attachment adjuvant, etc. are mentioned, for example.

A thermosetting resin is a component which hardens | cures by heating, becomes insoluble in a solvent, and has a function which prevents the intermixing between the underlayer film obtained and the resist film formed on it. As such thermosetting resins, various thermosetting resins can be used, but for example, acrylic resins (thermosetting acrylic resins), phenol resins, urea resins, melamine resins, amino resins, aromatic hydrocarbon resins, and epoxy resins Paper, alkyd resin, etc. are mentioned. Among these, urea resins, melamine resins and aromatic hydrocarbon resins are preferable.

It is preferable that it is 20 mass parts or less with respect to 100 mass parts of (A) polymers, and, as for the compounding quantity of a thermosetting resin, it is more preferable that it is 1-10 mass parts. When the said compounding quantity exceeds 20 mass parts, the intermixing between the underlayer film obtained and the resist film formed on it can be prevented favorably.

As a radiation absorbing agent, For example, dyes, such as oil-soluble dye, disperse dye, basic dye, methine dye, pyrazole type dye, imidazole type dye, and hydroxy azo type dye; Fluorescent brighteners such as bixin derivatives, norbiccin, stilbenes, 4,4'-diaminostilbene derivatives, coumarin derivatives and pyrazoline derivatives; Ultraviolet absorbers such as hydroxyazo dyes, trade names "tinuvin 234" and "tinuvin 1130" (above, manufactured by Ciba-Geigy Co., Ltd.); Aromatic compounds, such as an anthracene derivative and an anthraquinone derivative, etc. are mentioned. In addition, these radiation absorbers may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that it is 100 mass parts or less with respect to 100 mass parts of (A) polymers, and, as for the compounding quantity of a radiation absorber, it is more preferable that it is 1-50 mass parts.

Surfactant is a component which has the effect | action which improves applicability | paintability, abrasion, wettability, developability, etc .. As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene-n-octylphenyl ether, polyoxyethylene-n-nonylphenyl ether, polyethylene glycol Nonionic surfactants, such as a dilaurate and polyethyleneglycol distearate, and all the following brand names, "Dynaflo" (made by JSR company), "Suspinol" (made by Air Products), "Surpinol derivative" ( Air Products Co., Ltd.), "Dinol" (Air Air Products Co., Ltd.), "Dinol Derivatives" (Air Air Products Co., Ltd.), "Opin" (Air Products Co., Ltd.), "Olphin Derivatives" (Air Air Products Co., Ltd.), `` KP341 '' (manufactured by Shin-Etsu Chemical Co., Ltd.), `` Polyflow No. 75 '', `` Bridge No. 95 '' (above, Kyoeisha Oil & Chemicals Co., Ltd.), `` F-top EF101 '', `` Bridge EF204, East EF303, East EF352 In addition, Tochem Products Co., Ltd.), `` Megapack F171 '', `` East F172 '', `` East F173 '' (above, Dai Nippon Ink Chemical Industries, Ltd.), `` Fluorad FC430 '', `` East FC431 '', `` East FC135 '' '', `` East FC93 '' (above, Sumitomo 3M Co., Ltd.), `` Asahi Guard AG710 '', `` Suplon S382 '', `` East SC101 '', `` East SC102 '', `` East SC103 '', `` East SC104 '', `` East SC105 "," the same SC106 "(above, Asahi Glass Co., Ltd.), etc. are mentioned.

In addition, these surfactant may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that it is 15 mass parts or less with respect to 100 mass parts of (A) polymers, and, as for the compounding quantity of surfactant, it is more preferable that it is 0.001-10 mass parts.

[2] a method for producing an underlayer film-forming composition:

Although the manufacturing method of the underlayer film forming composition of this embodiment is not specifically limited, For example, first, (A) polymer, (B) crosslinking agent, and (D) acid generator are mixed, and (C) solvent is added to this mixture. Then, it adjusts so that it may become predetermined solid content concentration. Thereafter, the filter is filtered with a filter having a pore size of about 0.1 μm. In this way, an underlayer film forming composition can be obtained.

[3] a method for forming a dual damascene structure using an underlayer film forming composition:

The underlayer film forming composition of this embodiment can be used suitably for a multilayer resist process. That is, when the underlayer film forming composition is used, in addition to obtaining a good resist pattern, since the underlayer film forming composition is excellent in embedding property, the dual damascene structure with less damage to the inorganic film (low dielectric film) is satisfactorily obtained. Can be formed.

As a method for forming a dual damascene structure, for example, a first low dielectric insulating film having a first recessed portion formed in a predetermined pattern shape, the first first wiring being formed by embedding a conductive material in the first recessed portion. A predetermined second wiring is formed by embedding a conductive material in the second recessed portion of the step of forming a wiring layer (first wiring formation process) and a second low dielectric insulating film having a second recessed portion formed in a predetermined pattern shape. The first wiring is formed by embedding a conductive material in the third recess in the process of forming the second wiring layer (second wiring formation process) and the third low dielectric insulating film having the third recess formed in a predetermined pattern shape. And a step (third wiring formation step) of forming a third wiring layer on which the third wiring for connecting the second wiring is formed.

FIG. 5 shows an etching stopper layer 8 between the second low dielectric insulating film 7 and the third low dielectric insulating film 9, and between the third low dielectric insulating film 9 and the lower layer film 11. It is an example showing the state in which the etching stopper layer 10 was formed.

[3-1] First Wiring Formation Process:

The underlayer film forming composition of the present embodiment is used to form the concave portion. Specifically, the method for forming the concave portion in the first wiring forming step is specifically on the first low dielectric insulating film of the wafer on which the first low dielectric insulating film is formed. The process of forming an underlayer film by the underlayer film forming composition of this embodiment (underlayer film forming process), the process of forming a resist film on the formed underlayer film (resist film formation process), and a resist pattern in this resist film Forming a resist pattern (resist pattern forming process), using a resist film on which a resist pattern is formed, transferring a resist pattern of the resist film to an underlayer film by etching (first transfer process), and transferring the resist pattern. Using the underlayer film as a mask, the resist pattern of the underlayer film was formed on the first low dielectric insulating film disposed under the underlayer film. And a method of transferring the resist pattern and the underlayer film by plasma ashing (film removal step) after transferring the resist pattern to the first low dielectric insulating film. Can be mentioned.

[3-1-1] Underlayer Film Formation Step:

First, the process (lower layer film forming process) of forming a lower layer film by the lower layer film forming composition of this embodiment on the 1st low dielectric film of the wafer in which the 1st low dielectric insulating film was formed is performed. Thus, when the underlayer film forming composition of this embodiment is used, since this underlayer film forming composition has good embedding property, the low dielectric insulating film can be prevented from exposing to a plasma at the time of an etching. Therefore, the dual damascene structure can be satisfactorily formed without damaging the low dielectric insulating film.

Although the kind etc. are not specifically limited as long as the 1st low dielectric insulating film (Low-k film) is arrange | positioned under an underlayer film, For example, an inorganic film can be used. This inorganic film can be formed, for example with silicon oxide, silicon nitride, silicon oxynitride, polysiloxane, and the like. In particular, it can form with commercial items, such as "black diamond" (made by AMAT), "silk" (made by Dow Chemical), and "LKD5109" (made by JSR).

The first low dielectric insulating film is a film formed to cover a substrate such as a wafer. The formation method of a 1st low dielectric insulating film is not specifically limited, A well-known method can be used. For example, a spin on dielectric (SOD), a chemical vapor deposition (CVD) method, or the like can be used.

Although the method of forming an underlayer film by the underlayer film forming composition of this embodiment is not specifically limited, For example, a spin coating method, a spraying method, an immersion coating method, etc. are mentioned.

Although the film thickness of an underlayer film is not specifically limited, It is preferable that it is 100-2000 nm, It is more preferable that it is 200-1000 nm, It is especially preferable that it is 200-500 nm. If the film thickness of the underlayer film is less than 100 nm, the amount of mask sufficient for processing the substrate is not sufficient, and the substrate may not be processed. On the other hand, when it exceeds 2000 nm, when forming the resist pattern of a line and space, for example, the vertical / aspect ratio (aspect ratio) of a line part may become large, and a line part may fall.

[3-1-2] Resist Film Forming Step:

Next, the process of forming a resist film on the formed underlayer film is performed. The resist film can be formed by a resist composition. As this resist composition, a conventionally known composition can be used, but for example, a positive or negative chemically amplified resist composition containing a photoacid generator, a positive resist composition containing an alkali-soluble resin and a quinonediazide-based photosensitive agent And negative resist compositions containing alkali-soluble resins and crosslinking agents.

Although the method of forming a resist film on an underlayer film is not specifically limited, For example, a spin coating method etc. are mentioned. Specifically, the resist composition can be coated on the underlayer film by spin coating, and then pre-baked to form a resist film by volatilizing a solvent in the coating film. In addition, although the temperature of pre-firing can be suitably adjusted according to the kind etc. of the resist composition used, it is preferable that it is 30-200 degreeC, and it is more preferable that it is 50-150 degreeC.

Although the film thickness of a resist film is not specifically limited, It is preferable that it is 100-20000 nm, It is more preferable that it is 100-200 nm.

[3-1-3] Resist Pattern Forming Process:

Next, the process of forming a resist pattern in a resist film is performed. Formation of a resist pattern can be performed by irradiating (exposure) light, such as radiation, to a resist film through the mask (reticle) in which the desired device design was portrayed, and developing.

Although the radiation irradiated to a resist film can be suitably selected according to the kind of (D) acid generator contained in a resist film, For example, visible light, an ultraviolet-ray, an ultraviolet-ray, an X-ray, an electron beam, a gamma ray, a molecular beam, an ion beam Etc. can be mentioned. Among these, far ultraviolet rays are preferable, and in particular, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (wavelength 157 nm), Kr ₂ excimer laser (wavelength 147 nm), ArKr excimer laser ( Wavelength 134 nm) and extreme ultraviolet rays (13 nm wavelength and the like) are preferable.

The developing solution used for image development can be suitably selected according to the kind of resist composition. As a developing solution used for the positive chemically amplified resist composition and the positive resist composition containing alkali-soluble resin, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine , Diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline And alkaline aqueous solutions such as 1,8-diazabicyclo [5.4.0] -7-undecene and 1,5-diazabicyclo [4.3.0] -5-nonene. In addition, an appropriate amount of water-soluble organic solvents, for example, alcohols such as methanol and ethanol, and a surfactant may be added to these alkaline aqueous solutions.

In addition, after developing the resist film, the photoresist film is preferably washed and dried. In addition, post-firing may be performed after exposure and before development in order to improve the resolution, pattern profile, developability, and the like.

[3-1-4] First Transfer Process:

Next, using the resist film in which the resist pattern was formed as a mask, the process of transferring the resist pattern of a resist film to an underlayer film by etching is performed. For example, as shown in FIG. 1, the first low dielectric insulating film 2, the lower layer film 3, and the resist film 20 are disposed on the substrate 1 in order from the substrate 1 side. In this step, the resist pattern 14 of the resist film 20 is transferred to the underlayer film 3 by etching using the resist film 20 on which the resist pattern 14 is formed as a mask. 1-10 is a schematic diagram explaining one process of the formation method of a dual damascene structure.

An etching method is not specifically limited, It can carry out by a well-known method. That is, it may be dry etching or wet etching. When dry etching is used, the source gas may be, for example, a gas containing oxygen atoms such as O ₂ , CO, CO ₂ , inert gas such as He, N ₂ , Ar, chlorine gas such as Cl ₂ , BCl ₂ , In addition it can be used H _2, NH ₂ and the like. In addition, these source gases may be used individually by 1 type, and may be used in combination of 2 or more type.

[3-1-5] Second Transfer Process:

Next, using the underlayer film on which the resist pattern has been transferred as a mask, a step of transferring the resist pattern of the underlayer film to the first low dielectric insulating film disposed under the underlayer film is performed. Although there is no restriction | limiting in particular in the method of transferring the resist pattern of an underlayer film to a 1st low dielectric insulating film, The methods, such as the above-mentioned etching, are mentioned. In addition, this process can be performed by continuing to etch after transferring (ie, forming) a resist pattern to an underlayer film by the 1st transfer process mentioned above.

For example, as shown in FIG. 2, in this process, the lower layer film (3) is applied to the first low dielectric insulating film 2 disposed under the lower layer film 3 using the lower layer film 3 to which the resist pattern is transferred as a mask. The resist pattern of 3) is transferred, and the first recessed portion 4 is formed in the first low dielectric insulating film 2.

[3-1-6] Membrane Removal Process:

Next, after transferring a resist pattern to a 1st low dielectric insulating film, the process of removing a resist film and an underlayer film by plasma ashing is performed. Here, "plasma ashing" means generating a plasma of a reaction gas such as oxygen in a gaseous phase, and decomposing and removing organic substances such as a resist film and an underlayer film by CO _x , H ₂ O, etc. by this plasma. do.

The conditions for plasma ashing are not particularly limited as long as it is possible to remove the resist film and the underlayer film. For example, the high frequency power applied to the susceptor is preferably 100 to 1000 W, more preferably 100 to 500 W. In addition, the susceptor temperature is preferably 20 to 100 ° C, more preferably 20 to 60 ° C. Moreover, it is preferable that it is 1-300 mtorr, and, as for the pressure in a processing container, it is more preferable that it is 30-100 mtorr.

The gas used for plasma ashing is not particularly limited as long as it is possible to remove the resist film and the underlayer film, but from the viewpoint of suppressing an increase in the relative dielectric constant of the first low dielectric insulating film caused by plasma ashing, nitrogen, hydrogen, ammonia and argon It is preferable to include 1 or more types chosen from the group which consists of. In particular, it is preferable that they are a mixed gas of nitrogen and hydrogen, a mixed gas of ammonia and argon, and a mixed gas of ammonia, nitrogen and hydrogen.

In addition, when using the mixed gas of nitrogen and hydrogen, it is preferable that hydrogen is 20 or less with respect to nitrogen 100 by capacity ratio, and it is more preferable that hydrogen is 1-10. In addition, when using the mixed gas of ammonia and argon, it is preferable that argon is 10 or less with respect to ammonia 100 by volume ratio.

FIG. 3 shows that the resist film 20 and the lower layer film 3 shown in FIG. 2 are removed by plasma ashing, and the substrate 1 and the resist pattern disposed on the substrate 1 are transferred (first). The state in which the first low dielectric insulating film 2 (with the recessed portions 4) is formed remains.

Next, copper, aluminum, etc. are mentioned as an electrically-conductive material embedded in the recessed part of a 1st low dielectric insulating film. As a method of embedding a conductive material, copper electroplating etc. are mentioned, for example. In this way, the desired wiring structure can be formed by embedding the conductive material in the resist pattern. FIG. 5 is an example showing a state in which copper is embedded in the resist pattern (first recessed portion 4) formed in the first low dielectric insulating film 2 and the first wiring 6 is formed.

[3-1-7] Other Processes:

The above-described dual damascene structure formation method includes, in addition to the above steps, a step of forming an intermediate layer between the photoresist film and the lower layer film (intermediate layer forming step), the surface of the first low dielectric insulating film after the film removing step, and part of the substrate. The process of forming a barrier metal layer (barrier metal layer formation process) can also be performed.

[3-1-7a] Interlayer Forming Process:

In the intermediate layer formation step, the intermediate layer is a layer for compensating for the functions lacking in the underlayer film, the resist film, and both in forming the resist pattern. It is also possible to form an intermediate layer. That is, for example, when the underlayer film lacks an antireflection function, a film having an antireflection function can be applied to the intermediate layer.

The material of the intermediate layer can appropriately select an organic compound or an inorganic oxide according to the required function. In addition, when the resist film is an organic compound, it is also possible to apply an inorganic oxide to the intermediate layer.

As a commercial item of the organic compound for forming an intermediate | middle layer, all are brand names, for example, "DUV-42", "DUV-44", "ARC-28", "ARC-29" (above, Brewer Science company make), " AR-3 "," AR-19 "(above, Rom and Haas company), etc. are mentioned. Moreover, as an inorganic oxide for forming an intermediate | middle layer, polysiloxane, titanium oxide, alumina oxide, tungsten oxide, etc. are mentioned, for example. As all these commercial items, "NFC SOG01", "NFC SOG04" (above, JSR Corporation make) etc. are mentioned as a brand name, for example.

As the formation method of an intermediate | middle layer, a coating method, a CVD method, etc. can be used, for example. Among these, since an intermediate | middle layer can be formed continuously after forming an underlayer film, it is preferable to use a coating method.

Although the film thickness of an intermediate | middle layer can select suitably the film thickness according to the function calculated | required by the intermediate | middle layer, it is preferable that it is 10-3000 nm, and it is more preferable that it is 20-300 nm. If the film thickness of this intermediate | middle layer is less than 10 nm, there exists a possibility that an intermediate | middle layer may be scraped off during the etching of an underlayer film. On the other hand, when it exceeds 3000 nm, there exists a possibility that processing conversion difference may remarkably generate | occur | produce when transferring the resist pattern of a resist film to an intermediate | middle layer.

[3-1-7b] Barrier Metal Layer Forming Process:

In the barrier metal layer forming step, the barrier metal layer improves the adhesion between the conductive material and the low dielectric insulating film embedded in the resist pattern (that is, the recess formed in the first low dielectric insulating film). In addition, diffusion (migration) is prevented in the low dielectric insulating film of the conductive material.

As a material of a barrier metal layer, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, etc. are mentioned, for example.

The formation method of a barrier metal layer can be performed by CVD method etc., for example.

4 shows a state where the barrier metal layer 5 is formed on the surface of the first low dielectric insulating film 2 and the surface of the first recessed portion 4 of the first low dielectric insulating film 2.

After the lamination step, it is preferable to remove the conductive material and the barrier metal layer attached to the surface of the low dielectric insulating film by chemical polishing (CMP), and to planarize the surface of the low dielectric insulating film.

[3-2] Second Wiring Formation Process and Third Wiring Formation Process:

In the second wiring forming step and the third wiring forming step, the method of forming the recesses may employ the same method as the method of forming the recesses in the above-described first wiring forming step, but the recesses are formed by the following method. It is desirable to. That is, it is preferable to form a 2nd wiring layer and a 3rd wiring layer simultaneously.

First, a third low dielectric insulating film is formed on the first wiring layer formed by the first wiring forming step. Thereafter, a second low dielectric insulating film is formed on the third low dielectric insulating film. In addition, the second low dielectric insulating film and the third low dielectric insulating film may be the same as the first low dielectric insulating film described above, and the method of forming the second low dielectric insulating film and the third low dielectric insulating film may be the first low dielectric insulating film described above. The same method as can be employed.

Next, a third recess is formed in the second low dielectric insulating film and the third low dielectric insulating film. The method of forming a 3rd recessed part can employ | adopt the method similar to the method of forming a 1st recessed part mentioned above. FIG. 6 shows an example in which a third recessed portion 12 is formed in the second low dielectric insulating film 9 and the third low dielectric insulating film 7.

Next, a second recess is formed in the second low dielectric insulating film. The method of forming a 2nd recessed part can employ | adopt the method similar to the method of forming a 1st recessed part mentioned above. Specifically, it can be performed as follows.

First, the lower layer insulating film forming composition of the present embodiment is coated on the second low dielectric insulating film, and the third recessed portions formed in the second low dielectric insulating film and the third low dielectric insulating film are filled with the second low dielectric insulating film. A film (underlayer film) is formed on the surface. In addition, the method of apply | coating an underlayer film forming composition is not specifically limited, For example, a spin coating method, a spraying method, an immersion coating method, etc. are mentioned.

Next, after forming a resist film on the formed underlayer film, a resist pattern is formed in this resist film. Next, using the resist film in which the resist pattern was formed as a mask, the resist pattern of the resist film is transferred to the underlayer film by etching. FIG. 7 shows a state where the resist pattern of the resist film 22 is transferred to the lower layer film 13 by etching using the resist film 22 on which the resist pattern is formed as a mask.

Next, using the underlayer film on which the resist pattern has been transferred as a mask, the resist pattern of the underlayer film is transferred to the second low dielectric insulating film disposed under the underlayer film. FIG. 8 shows that the resist pattern of the underlayer film 13 is transferred to the second low dielectric insulating film 9 disposed under the underlayer film 13 by using the underlayer film 13 on which the resist pattern is transferred (the second layer). The recess 14 is formed).

Next, the resist film and the underlayer film are removed by plasma ashing. At this time, the thing which hardened the underlayer film forming composition which filled the 3rd recessed part formed in the 3rd low dielectric insulating film by plasma ashing is removed. FIG. 9 shows that the resist film 22 and the underlayer film 13 shown in FIG. 8 are removed by plasma ashing, and the second recesses are formed in the second low dielectric insulating film 9 and the third low dielectric insulating film 7, respectively. The state in which 14 and the 3rd recessed part 12 were formed is shown.

Next, by embedding the conductive material in the second concave portion and the third concave portion, it is possible to simultaneously form the second wiring and the third wiring for connecting the first wiring and the second wiring. In addition, the above-mentioned barrier metal layer may be formed before embedding the conductive material in the second concave portion and the third concave portion. FIG. 10 shows the barrier metal layer 15 before embedding the conductive material in the second concave portion 14 and the third concave portion 12 shown in FIG. 9, and then the second concave portion 14 and the first concave portion 14 are formed. By embedding the conductive material in the third concave portion 12, the state in which the second wiring 31 and the third wiring 16 connecting the first wiring 6 and the second wiring 31 are simultaneously formed is shown. have. Thus, the 1st wiring layer 25 in which the 1st wiring 6 was formed, the 2nd wiring layer 29 in which the 2nd wiring 31 was formed, the said 1st wiring 6 and the said 2nd wiring 31 were formed. ), A dual damascene structure 100 having a third wiring layer 27 on which the third wiring 16 to be connected is formed can be manufactured.

In addition, after the conductive material is embedded in the second concave portion and the third concave portion, chemical polishing (CMP) can be performed.

<Example>

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples and a comparative example. In addition, "part" and "%" in description of an Example are mass references | standards unless there is particular notice.

Synthesis Example 1

Acenaphthylene (in Tables 1 and 2) as a monomer (shown as “monomer (1)” in Tables 1 and 2) which provides a structural unit represented by the formula (1) to a separating flask equipped with a thermometer under a nitrogen atmosphere. Hydroxyethyl methacrylate (in Table 1) as a monomer (shown as "monomer (2)" in Tables 1 and 2), which provides 70 parts and the structural unit represented by the formula (2). Styrene (in Tables 1 and 2), 20 parts and a monomer (shown as "monomer (3)" in Tables 1 and 2) providing a structural unit represented by the formula (3). 2,2'-azobis (dimethyl 2-methylbutyrate) (manufactured by Wako Pure Chemical Industries, Ltd.) as 10 parts and a radical polymerization initiator (monomer which provides the structural unit represented by Formula 4) as 10 parts of "M-3-1" 10 parts of brand name "V-601" and "polymerization initiator [V-601]" in Table 1, and 400 parts of methyl isobutyl ketones, The polymerization was carried out at 90 ° C. for 4 hours with stirring. After the completion of the polymerization, the polymerization solution was cooled with water and cooled to 30 ° C or lower. After cooling, this polymerization solution was thrown into a large amount of methanol to precipitate a white solid. Thereafter, the precipitated white solid was separated by decantation, and the separated white solid was washed with a large amount of methanol. After washing, the resultant was dried at 50 ° C. for 17 hours to obtain a polymer (A-1).

About the obtained polymer (A-1), the weight average molecular weight (Mw) was measured on the conditions shown below.

[Measurement of Weight Average Molecular Weight (Mw)]:

Monodisperse polystyrene was used as a standard under analytical conditions of using a GPC column (G2000HXL: 2, G3000HXL: 1) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, and column temperature: 40 ° C. It measured by the gel permeation chromatograph (detector: differential refractometer). In addition, in Table 1 and Table 2, it shows with "molecular weight."

The weight average molecular weight (Mw) of the polymer (A-1) obtained in this synthesis example was 2800. Synthesis Examples 2 to 26

Polymer (A-2) to polymer (A-26) were synthesized in the same manner as in Synthesis Example 1, except that the monomers shown in Table 1 and the radical polymerization initiator were used in the compounding amounts shown in Table 1, and the weight average molecular weight for each polymer was shown. (Mw) was measured. The results are shown in Table 1. In addition, in Tables 1-4, "part" shows a mass part.

Synthesis Example 27

50 parts of acenaphthylene, 50 parts of hydroxymethylacenaphthylene (indicated as "M-1-2" in Tables 1 and 2) and azoisobutyti as a radical polymerization initiator in a separate flask equipped with a thermometer under a nitrogen atmosphere. 25 parts of ronitrile (it shows as "a polymerization initiator [AIBN] in Table 2), and 400 parts of methyl isobutyl ketones were added, and it superposed | polymerized at 60 degreeC for 15 hours, stirring. After the completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or less. After cooling, this polymerization solution was thrown into a large amount of n-heptane to precipitate a white solid. Thereafter, the precipitated white solid was separated by decantation and washed with a large amount of n-heptane. After washing, the resultant was dried at 50 ° C. for 17 hours to obtain a polymer (CA-1).

The weight average molecular weight (Mw) of the polymer (CA-1) obtained in this synthesis example was 1300.

Synthesis Examples 28 to 31

Except having used the monomer and radical polymerization initiator shown in Table 2 in the compounding quantity shown in Table 2, polymer (CA-2)-the polymer (CA-5) were synthesize | combined similarly to the synthesis example 30, and the weight average molecular weight with respect to each polymer (Mw) was measured. The results are shown in Table 2.

In addition, in Tables 1 and 2, "M-2-2" represents hydroxyethyl acrylate, "M-3-2" represents hydroxymethyl styrene, and "M-3-3" is tert-part. It represents oxy styrene.

(Example 1)

10.0 parts of polymers (A-1) obtained in Synthesis Example 1 and (B) a compound represented by the following formula (7) as a crosslinking agent (tetrabutoxymethylglycoluril (manufactured by Nippon Carbide)), Tables 3 and 4, "B-1 86.5 parts of propylene glycol monomethyl ether acetate (in Tables 3 and 4, represented by "C-1") as 3.0 parts, (C) solvent, and bis (4-t-) as an acid generator (D) Butylphenyl) iodonium nonafluoro-n-butanesulfonate (Mido Kagaku Co., Ltd. make, brand name "BBI-109", Table 3, 4, and it shows "D-1") 0.5 parts is mixed, it is made to dissolve A mixed solution was obtained. The obtained mixed solution was filtered with the membrane filter of 0.1 micrometer of pore diameters, and the underlayer film forming composition was prepared.

Each performance evaluation shown below was performed about the manufactured underlayer film forming composition.

(1) etching resistance:

An underlayer film-forming composition was applied onto a silicon substrate by a spin coating method, and after baking at 220 ° C. for 60 seconds, an underlayer film having a film thickness of 300 nm was formed. Thereafter, the underlayer film was etched (pressure: 0.03 Torr, high frequency power: 300 W, Ar / CF ₄ = 40/100 sccm, substrate temperature: 20 ° C), and the film thickness of the underlayer film after the etching treatment was measured. And the etching rate (nm / min) was computed from the relationship between the decrease of the film thickness, and processing time, and it was set as the evaluation criteria of etching tolerance (it shows as "etching rate (nm / min) in Tables 5 and 6"). . In addition, the smaller the value of this etching rate, the better the etching resistance.

(2) landfill:

It was evaluated as follows whether or not the underlayer film-forming composition penetrated well into the via hole and was buried satisfactorily.

First, after coating the underlayer film-forming composition on a substrate of tetraethylorthosilicate (TEOS) having a via hole having a via size of 70 nm, a beer pitch of 1H / 1.2S, and a depth of 400 nm, the resultant was spin-coated at 200 ° C. for 60 seconds. Heated on hot plate. In this way, an underlayer film was prepared in the via hole and on the TEOS surface. In addition, the film thickness of the underlayer film was 300 nm. Next, the state of the underlayer film embedded in the via hole was observed with a scanning electron microscope to evaluate the embedding. In the evaluation criteria, the case where the lower layer film was formed in the via hole, that is, the case where the lower layer film was embedded in the via hole was "o", and the case where the lower layer film was not embedded in the via hole was "x".

(3) curing temperature:

The underlayer film forming composition was apply | coated on the silicon substrate by the spin coating method, and it baked for 60 second at 140-400 degreeC, and obtained the underlayer film. The obtained underlayer film was immersed in propyl glycol monomethyl ether acetate for 1 minute at room temperature. And the film thickness change of the underlayer film before and behind immersion was measured using the spectroscopic ellipsometer "UV1280E" (made by KLA-TENCOR), and evaluation was performed. Evaluation criteria set the minimum temperature at which the film thickness change is not recognized among the predetermined temperatures as "curing temperature" (in Tables 5 and 6, "curing temperature (° C)"). Moreover, even if it baked at the temperature of 250 degreeC, when the change of film thickness was observed, it was set as "x."

(4) Sublimation Quantity:

The underlayer film forming composition was spin-coated on a silicon substrate 8 inches in diameter. Then, it heated on the hotplate for 60 second at 140-400 degreeC, and obtained the underlayer film with a film thickness of 300 nm. At this time, the amount of the sublimate generated from the underlayer film was measured (in Tables 5 and 6, the "sublimate amount (mg)"). In addition, collection of the sublimate was performed as follows. First, a hot plate was prepared. Next, the 8-inch silicon wafer which weighed previously was attached to the top plate of this hot plate. Next, after heating a hot plate, the underlayer film forming composition was spin-coated on the silicon substrate, and it heated with the hot plate. Next, the underlayer film forming composition was spin-coated on the underlayer film of the silicon substrate which spin-coated this underlayer film forming composition, and it heated with the hotplate. And these processes were performed 100 times. Thereafter, the weight of the 8 inch silicon wafer attached to the top plate was measured. Next, the difference in the weight of the 8-inch silicon wafer was calculated to be the sublimation amount, and the magnitude of the sublimation amount was confirmed.

(5) refractive index:

The underlayer film forming composition was apply | coated on the silicon substrate by the spin-coating method, and after baking at 200 degreeC for 60 second, the underlayer film of a film thickness of 300 nm was obtained. Thereafter, an optical constant (refractive coefficient) at a wavelength of 193 nm was calculated using a spectroscopic ellipsometer "VUV-VASE" (manufactured by JAWoollam) (in Tables 5 and 6, the "refractive coefficient (n value)). ”). If the refractive index (n value) is within the range of 1.40 to 1.60, it can be determined that the ArF exposure resist process has a sufficient function as an antireflection film.

(6) damping coefficient:

The underlayer film forming composition was apply | coated on the silicon substrate by the spin-coating method, and after baking at 200 degreeC for 60 second, the underlayer film of a film thickness of 300 nm was obtained. Thereafter, an optical constant (attenuation coefficient) at a wavelength of 193 nm was calculated using a spectroscopic ellipsometer "VUV-VASE" (manufactured by JAWoollam) (in Tables 5 and 6, the "damping coefficient (k value)). ”). If the attenuation coefficient (k value) is within the range of 0.25 to 0.40, it can be determined that the ArF exposure resist process has a sufficient function as an antireflection film.

In this example, the results of the above-described performance evaluations show that the etching resistance is 67, the embedding property is "○", the curing temperature is 180 ° C, the sublimation amount is 1.8 mg, the refractive index is 1.55, and the attenuation. The coefficient was 0.28.

(Examples 2 to 36, Comparative Examples 1 to 10)

Except having set it as the various components and compounding quantity shown to Tables 3 and 4, the underlayer film forming composition was produced like Example 1, and each performance evaluation mentioned above was performed about this underlayer film forming composition. The evaluation results are shown in Tables 5 and 6.

In addition, in Tables 3 and 4, "B-2" represents the compound (n-butylether hexamethylolmelamine) represented by following formula (8), and "B-3" shows the compound represented by following formula (Tetra) Methoxymethylglycoluril).

As is apparent from Tables 5 and 6, the underlayer film formed by the underlayer film forming compositions of Examples 1 to 36 was superior to the underlayer film formed by the underlayer film forming compositions of Comparative Examples 1 to 10 and was excellent in etching resistance and embedding properties. In addition, it was confirmed that the amount of the sublimate was small. In addition, since the underlayer film formed by the underlayer film forming compositions of Examples 1 to 36 is in the optimum range that the n value and the k value have a sufficient function as an antireflection film in an ArF exposure resist process, the function as an antireflection film is sufficiently satisfied. It was confirmed that there was.

On the other hand, the underlayer film formed by the underlayer film forming compositions of Comparative Examples 1 to 10 was not a good underlayer film having good etching resistance, embedding properties, sublimation amount, and function as an antireflection film.

Specifically, since the underlayer film-forming compositions of Comparative Examples 1 to 3 contained the polymer (A) having a small weight average molecular weight, the embedding properties were excellent, but the sublimation amount was large. On the other hand, since the underlayer film forming composition of Comparative Example 4 contains the polymer (A) having a large weight average molecular weight, the sublimation amount was small, but good embedding was not obtained. In addition, since the underlayer film forming compositions of Comparative Examples 7, 8 did not have a suitable crosslinking group in the structure of the polymer (A) contained, they did not harden | cure at low temperature below 250 degreeC. In addition, in the underlayer film forming compositions of Comparative Examples 5-10, k value was not in the optimum range. Moreover, since the (A) polymer contained in the underlayer film forming compositions of Comparative Examples 7-10 does not have a structural unit (2), it was confirmed that embedding property is bad.

The underlayer film-forming composition of the present invention is a method for manufacturing a semiconductor device, specifically, depositing a plurality of substances as a processing film on a silicon wafer to form an underlayer film for use in forming a desired pattern on the processing film, respectively. Preferred as a composition for.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows one process of the formation method of the dual damascene structure using the underlayer film forming composition of this invention.

It is a schematic diagram which shows the dual damascene structure obtained using the underlayer film forming composition of this invention.

<Brief description of symbols for the main parts of the drawings>

1: substrate, 2: first low dielectric insulating film, 3, 11, 13: lower layer film, 4: first recessed portion, 5, 15: barrier metal layer, 6: first wiring, 7: third low dielectric insulating film, 8 10: etching stopper layer, 9: second low dielectric insulating film, 12: third recessed portion, 14: second recessed portion, 16: third wiring, 20, 21, 22: resist film, 25: first wiring layer, 27: third wiring layer, 29: second wiring layer, 31: second wiring, 100: barrier metal layer.

Claims (5)

(A) a polymer having a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4), (B) a crosslinking agent having a butyl ether group, (C) Underlayer film forming composition containing a solvent. <Formula 1>

(However, in formula (1), R ¹ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, 1 to C carbon 6 alkoxycarbonyloxy group, methylol group, or alkoxymethylol group having 1 to 6 carbon atoms, R ² and R ³ each represent a hydrogen atom or an alkyl group which may be substituted with 1 to 6 carbon atoms) <Formula 2>

(However, in formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkylene group having 1 to 4 carbon atoms) <Formula 3>

(However, in the above formula (3), R ⁶ is a hydrogen atom, an alkyl group which may be substituted with 1 to 6 carbon atoms, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms, a carboxyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, C 1 to C 6 represents an alkoxycarbonyloxy group, a methylol group, or an alkoxymethylol group having 1 to 6 carbon atoms, R ⁷ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 3 Indicates) <Formula 4>

(However, in Formula 4, R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, optionally substituted alkyl group of 1 to 6 carbon atoms) The underlayer film forming composition of Claim 1 whose weight average molecular weights (Mw) of polystyrene conversion of the said (A) polymer are 500-10000. The underlayer film formation composition of Claim 1 or 2 whose said (B) crosslinking agent is a compound represented by following formula (5) or (6). <Formula 5>

(However, in formula (5), R ¹¹ each independently represent a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that at least two of four R ¹¹ is n-butyl group or iso- Butyl) <Formula 6>

(However, in Formula 6, R ¹² independently represents a hydrogen atom, a methyl group, n-butyl group or iso-butyl group, provided that at least two of six R ¹² is n-butyl group or iso- Butyl) The ratio of the structural unit represented by the said Formula (1) contained in the said (A) polymer is 5 to 80 with respect to 100 mol% of all the structural units of the said (A) polymer. Mole%, The ratio of the structural unit represented by the said Formula (2) contained in the said (A) polymer is 5-80 mol% with respect to 100 mol% of all the structural units of the said (A) polymer, The underlayer film forming composition whose ratio of the structural unit represented by the said Formula (3) contained in the said (A) polymer is 0.1-50 mol% with respect to 100 mol% of all the structural units of the said (A) polymer. The underlayer film forming composition according to any one of claims 1 to 4, further comprising (D) an acid generator.

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