JP2008085063A - Etching stopper film forming composition, film using the composition, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming an etching stopper film which can form an etching stopper insulation film having a high etching selectivity with respect to both inorganic and organic system interlayer insulation films which apply to an interconnection layer and a Via layer and also having a low dielectric constant, and to provide a film and an electronic device which use the composition. <P>SOLUTION: The composition for forming an etching stopper film contains a hydrosilylated polymer (A) obtained by reaction between hydridesilsesquioxanes expressed by a specific general expression and a polyin compound expressed by a specific general expression. The film formed of this composition and the electronic device having the film are also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film-forming composition having good film properties such as dielectric constant, mechanical strength, heat resistance and the like used for electronic devices, and further relates to an electronic device having a film obtained by using the film-forming composition. .

  In recent years, in the field of electronic materials, with the progress of higher integration, more functions, and higher performance, circuit resistance and capacitor capacity between wirings have increased, leading to an increase in power consumption and delay time. In particular, an increase in delay time is a major factor in reducing the signal speed of the device and the occurrence of crosstalk. Therefore, in order to reduce the delay time and speed up the device, it is necessary to reduce parasitic resistance and parasitic capacitance. It has been. As a specific measure for reducing this parasitic capacitance, an attempt has been made to cover the periphery of the wiring with a low dielectric interlayer insulating film. In addition, the interlayer insulating film is required to have excellent heat resistance that can withstand subsequent steps such as a thin film formation process, chip connection, and pinning during manufacturing of a mounting substrate, and chemical resistance that can withstand a wet process. Furthermore, in recent years, low resistance Cu wiring has been introduced from Al wiring, and along with this, planarization by CMP (Chemical Mechanical Polishing) has become common, and high mechanical strength that can withstand this process is required. It has been.

At present, as an interlayer insulating film in wiring layers and via layers in electronic devices, silicon oxide (SiO ₂ ), fluorine-containing silicon oxide (SiOF), carbon-containing silicon oxide (SiOC), spin-on glass (SOG), organosilicate glass Both inorganic materials such as methyl silsesquioxane (MSQ), hydrogen silsesquioxane (HSQ), and polyorganosiloxane and organic materials composed of organic polymers have been proposed.

  Dry etching is used for fine processing of the interlayer insulating film applied to the wiring layer / via layer as described above. Inorganic materials may be finely processed by dry etching mainly composed of fluorocarbon and halogen gases, and organic materials may be finely processed by dry etching mainly composed of a mixed gas of nitrogen and hydrogen and ammonia gases. Many. An etching stopper film having an etching selectivity with respect to the insulating film is provided on the base of the insulating film of the wiring layer or the Via layer. This serves to stop dry etching of the wiring layer / via layer insulating film, and further prevent etching damage from entering into the underlying insulating film structure, and Cu diffusion to prevent Cu from diffusing from the lower layer Cu wiring. It may also serve as a barrier function.

  Conventionally, SiN (silicon nitride film), SiC (silicon carbide film), SiCN (silicon carbonitride film), etc. deposited mainly by plasma CVD have been mainly used as an etching stopper film. However, these etching stoppers have a high relative dielectric constant of 4 to 7, and when applied to a multilayer wiring structure of an electronic device, there is a problem that the effective dielectric constant of the wiring structure as a whole becomes high and the propagation delay cannot be sufficiently improved. It has been pointed out. Therefore, there is a demand for an etching stopper film material having a low dielectric constant while having the high etching selectivity of SiN, SiCN, SiC, etc., and a method using a coating solution containing carbosilane is known. (Patent Document 1).

JP 2004-186610 A

  The present invention solves the problems of the prior art as described above, and has a high etching selectivity with both the inorganic interlayer insulating film and the organic interlayer insulating film applied to the wiring layer and the Via layer. An object of the present invention is to provide a composition for forming an etching stopper film capable of forming an etching stop insulating film having a low dielectric constant, a film formed using the composition, and an electronic device having the film.

It has been found that the above problems can be solved by the following <1> to <4> configurations.
<1> An etching stopper film comprising a hydrosilylated polymer (A) obtained by a reaction with a hydridosilsesquioxane represented by the following general formula (1) and a polyyne compound represented by the following general formula (2) Forming composition.
(HSiO _3/2 ) _n (R ¹ SiO _3/2 ) _m (1)
R ′ (— C≡C—R ² ) _k (2)
In the general formula (1), R ¹ represents a monovalent organic group.
n represents an integer of 1 to 20, and m represents an integer of 0 to 19. N + m is an integer of 4 to 20.
In the general formula (2), R ² represents a monovalent organic group, and R ′ represents a k-valent organic group.
k represents an integer selected from 1 to 6.

<2> The composition for forming an etching stopper film according to <1>, wherein the carbon content of the hydrosilylated polymer (A) is 55% by mass to 85% by mass.
<3> A film formed from the composition for forming an etching stopper film according to <1> or <2>.
<4> An electronic device having the film according to <3>.

  According to the present invention, it is possible to provide an insulating film having a high etching selectivity with respect to both of the inorganic interlayer insulating film and the organic interlayer insulating film, having a low dielectric constant, and suitable for etching stop.

  Although the material which can be contained in the composition for forming an etching stop insulating film of the present invention is described in detail below, it does not indicate that the present invention is limited to these.

Hydrosilylated polymer The composition for forming an etching stop insulating film of the present invention includes a hydridosilsesquioxane represented by the following general formula (1) and a polyyne compound represented by the following general formula (2). The hydrosilylation polymer (A) obtained by reaction is included.
(HSiO _3/2 ) _n (R ¹ SiO _3/2 ) _m (1)
R ′ (— C≡C—R ² ) _k (2)
In the general formula (1), R ¹ represents a monovalent organic group.
n represents an integer of 1 to 20, and m represents an integer of 0 to 19. N + m is an integer of 4 to 20.
In the general formula (2), R ² represents a monovalent organic group, and R ′ represents a k-valent organic group.
k represents an integer selected from 1 to 6.

The carbon content of the hydrosilylated polymer (A) is preferably 55 to 85% by mass, more preferably 60 to 80% by mass. When the carbon content is within the range, the etching selectivity with both the inorganic interlayer insulating film and the organic interlayer insulating film can be easily increased. The carbon content of the hydrosilylated polymer (A) can be adjusted within the above range depending on the structure and charging ratio of the hydridosilsesquioxane (1) and the polyyne compound (2).

Examples of the monovalent organic group represented by R ¹ in the general formula (1) include an alkyl group, an alkenyl group, and an alkynyl group, and preferably an alkyl group or alkenyl group having 1 to 4 carbon atoms. And an alkynyl group, for example, a methyl group, a vinyl group, and an ethynyl group.
The hydridosilsesquioxanes represented by the general formula (1) have n (HSiO _3/2 ) units and m (R ¹ SiO _3/2 ) units sharing the oxygen atom. It is preferable that the ring structure is formed by connecting with other (HSiO _3/2 ) units or (R ¹ SiO _3/2 ) units.

  Although the preferable specific example of hydrido silsesquioxane which can be applied to this invention is shown below, it does not show that this invention is limited to these. Of the silsesquioxanes represented by the following (Q-6), it is particularly preferred that all R are hydrogen atoms as the raw material of the hydrosilylation polymer.

In the polyyne compound represented by the general formula (2),
The k-valent organic group of R ′ is preferably a polycyclic hydrocarbon residue or aromatic hydrocarbon residue having 6 to 14 carbon atoms, more preferably a benzene residue, a naphthalene residue, an anthracene residue, or a norbornene residue. An adamantane residue, a diamantane residue, and a biadamantan residue. Most preferred are a benzene residue, an adamantane residue, and a diamantane residue. k represents an integer of 1 to 6, preferably 2 to 4.
The monovalent organic group of R ² is preferably a polycyclic alkyl group having 6 to 20 carbon atoms or an aryl group, more preferably a phenyl group, a naphthyl group, an anthranyl group, a norbornyl group, an adamantyl group, or a diamantyl group. Most preferably, they are a phenyl group, an adamantyl group, and a diamantyl group.

  Specific examples of the polyyne compound represented by the general formula (2) are shown below, but the present invention is not limited to these.

The hydrosilylation polymer (A) of the present invention comprises a hydrosilylation reaction of (1) hydridosilsesquioxane and (2) polyyne compound as described above by the production method described in JP-A-9-296043. Can be synthesized.
The polymer (A) of the present invention is a hydrosilylation polymerization of hydridosilsesquioxane represented by the general formula (1) and the polyyne compound represented by the general formula (2) in a molar ratio of usually 2: 1 to 1: 4. It is a solid polymer obtained by making it have heat resistance and solvent solubility. The weight average molecular weight of this polymer is 1000-100000, preferably 3000-50000, most preferably 5000-30000.

  The hydrosilylation polymerization reaction can be performed using a platinum-containing catalyst. As the platinum-containing catalyst, those conventionally used for hydrosilylation reactions can be used. For example, platinum divinylsiloxane, platinum cyclic vinylmethylsiloxane, tris (dibenzylideneacetone) diplatinum, chloroplatinic acid, bis (ethylene) tetrachlorodiplatinum, cyclooctadiene chloroplatinum, bis (cyclooctadiene) Examples thereof include platinum, bis (dimethylphenylphosphine) dichloroplatinum, tetrakis (triphenylphosphine) platinum, and platinum carbon.

  In the hydrosilylation polymerization reaction, various solvents usually used in this reaction can be used. For example, toluene, benzene, hexane, ether and the like can be mentioned.

The hydrosilylation polymerization reaction can be carried out at various temperatures from 0 ° C. to the boiling point of the reaction solvent, but can be carried out at room temperature without particularly heating or cooling.
In this reaction, the ratio of hydridosilsesquioxane (1) to polyyne compound (2) is usually 2: 1 to 1: 4, preferably 1.5: in terms of yield and solubility. A range of 1-1: 2 is desirable.

(B) Coating solvent Although the coating solvent (B) used for the composition for forming an etching stopper film of the present invention is not particularly limited, for example, methanol, ethanol, 2-propanol, 1-butanol, 2-ethoxymethanol, 3- Alcohol solvents such as methoxypropanol and 1-methoxy-2-propanol, ketones such as acetone, acetylacetone, methyl ethyl ketone, methyl isobutyl ketone, 2-pentanone, 3-pentanone, 2-heptanone, 3-heptanone, cyclopentanone, cyclohexanone Solvent, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, ethyl propionate, propyl propionate, butyl propionate, isobutyl propionate, propylene glycol monomethyl ether acetate, lactic acid Ester solvents such as methyl, ethyl lactate, γ-butyrolactone, ether solvents such as diisopropyl ether, dibutyl ether, ethyl propyl ether, phenetol, veratrol, mesitylene, ethylbenzene, diethylbenzene, propylbenzene, t-butylbenzene, xylene, anisole And aromatic hydrocarbon solvents such as N-methylpyrrolidinone, dimethylacetamide, and the like. These may be used alone or in admixture of two or more.
More preferable coating solvents are 1-methoxy-2-propanol, propanol, acetylacetone, cyclohexanone, propylene glycol monomethyl ether acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolactone, mesitylene, t-butylbenzene, xylene, and anisole. Particularly preferred are 1-methoxy-2-propanol, cyclohexanone, propylene glycol monomethyl ether acetate, ethyl lactate, γ-butyrolactone, t-butylbenzene, xylene and anisole.
When the composition for forming an etching stopper film of the present invention is used also as a Cu diffusion barrier film, the composition is directly applied on Cu wiring / Via, and therefore a low-polarity solvent having low Cu solubility should be used. Is preferred. Specifically, the solvents described as the above aromatic hydrocarbon solvents are preferable, and xylene, anisole, and t-butylbenzene are more preferable.

(C) Surfactant A surfactant (C) can be appropriately added to the composition for forming an etching stopper film of the present invention in order to adjust the film thickness uniformity of the coating film. Examples of the surfactant (C) that can be added include nonionic surfactants, anionic surfactants, and cationic surfactants. Further, silicone surfactants, fluorine-containing surfactants, Examples include polyalkylene oxide surfactants and acrylic surfactants. The surfactant used in the present invention may be one type or two or more types. As the surfactant, silicone surfactants, nonionic surfactants, fluorine-containing surfactants, and acrylic surfactants are preferable, and silicone surfactants are particularly preferable.

  The addition amount of the surfactant used in the present invention is preferably 0.01% by mass or more and 1% by mass or less, and 0.1% by mass or more and 0.5% by mass or less with respect to the total amount of the film-forming coating solution. More preferably.

  In the present invention, the silicon-based surfactant is a surfactant containing at least one Si atom. The silicon-based surfactant used in the present invention may be any silicon-based surfactant, and preferably has a structure containing alkylene oxide and dimethylsiloxane. A structure including the following chemical formula is more preferable.

  In the formula, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, x is an integer of 1 to 20, and m and n are each independently an integer of 2 to 100. A plurality of R may be the same or different.

  Examples of the silicon-based surfactant used in the present invention include BYK306, BYK307 (manufactured by Big Chemie), SH7PA, SH21PA, SH28PA, SH30PA (manufactured by Toray Dow Corning Silicone), Troysol S366 (manufactured by Troy Chemical). Can be mentioned.

  Any nonionic surfactant may be used as the nonionic surfactant used in the present invention. For example, polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, polyoxyethylene dialkyl esters, sorbitan fatty acid esters, fatty acid-modified polyoxyethylenes, polyoxyethylene-polyoxypropylene block copolymers, etc. Can do.

  As the fluorine-containing surfactant used in the present invention, any fluorine-containing surfactant may be used. For example, perfluorooctyl polyethylene oxide, perfluorodecyl polyethylene oxide, perfluorodecyl polyethylene oxide and the like can be mentioned.

  The acrylic surfactant used in the present invention may be any acrylic surfactant. For example, a (meth) acrylic acid type copolymer etc. are mentioned.

(D) Other film property modifiers Further, the composition for forming an etching stopper film of the present invention does not impair the properties of the resulting film (heat resistance, dielectric constant, mechanical strength, coating property, adhesion, etc.). In addition, additives such as a radical generator, colloidal silica, a silane coupling agent, an adhesion agent, and a pore forming agent may be added.

  Any colloidal silica may be used in the present invention. For example, a dispersion in which high-purity silicic acid is dispersed in a hydrophilic organic solvent or water, usually having an average particle size of 5 to 30 nm, preferably 10 to 20 nm, and a solid content concentration of about 5 to 40% by mass It is.

  Any silane coupling agent may be used in the present invention. For example, 3-glycidyloxypropyltrimethoxysilane, 3-aminoglycidyloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Glycidyloxypropylmethyldimethoxysilane, 1-methacryloxypropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N -(2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-triethoxysilylpropyltriethylenetriamine, 10- Trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6 -Diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyl Triethoxysilane, - bis (oxyethylene) -3-aminopropyltrimethoxysilane, N- bis (oxyethylene) -3-aminopropyltriethoxysilane and the like. The silane coupling agent used in the present invention may be one type or two or more types.

  Any adhesion promoter may be used in the present invention. For example, trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane , Γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, trimethoxyvinylsilane, γ-aminopropyltriethoxysilane, aluminum monoethylacetoacetate diisopropylate, vinyltris (2 -Methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3- Chloropropyltrimethoxy Sisilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethyl Vinylethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, N, N′-bis (trimethylsilyl) urea, dimethyltrimethylsilylamine, trimethylsilylimidazole, vinyltrichlorosilane, benzotriazole, benzimidazole, indazole, Imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-merca Examples thereof include putobenzoxazole, urazole, thiouracil, mercaptoimidazole, mercaptopyrimidine, 1,1-dimethylurea, 1,3-dimethylurea, and thiourea compounds. Functional silane coupling agents are preferred as adhesion promoters. The preferable use amount of the adhesion promoter is preferably 10 parts by mass or less, particularly 0.05 to 5 parts by mass with respect to 100 parts by mass of the total solid content.

The composition for forming an etching stopper film of the present invention can use a pore forming factor within the range allowed by the mechanical strength of the film to make the film porous and reduce the dielectric constant.
The pore-forming factor as an additive that becomes a pore-forming agent is not particularly limited, but a non-metallic compound is preferably used, and the solubility in a solvent used in a coating solution for film formation, the polymer of the present invention. It is necessary to satisfy the compatibility with. Further, the boiling point or decomposition temperature of the pore forming agent is preferably 100 to 500 ° C, more preferably 200 to 450 ° C, and particularly preferably 250 to 400 ° C. The molecular weight is preferably 200 to 50,000, more preferably 300 to 10,000, and particularly preferably 400 to 5,000. The addition amount is preferably 0.5 to 75%, more preferably 0.5 to 30%, and particularly preferably 1 to 20% by mass% with respect to the polymer forming the film. Further, as a pore forming factor, a polymer may contain a decomposable group, and the decomposition temperature is preferably 100 to 500 ° C, more preferably 200 to 450 ° C, particularly preferably 250 to 400 ° C. Good to have. The content of the decomposable group is 0.5 to 75%, more preferably 0.5 to 30%, and particularly preferably 1 to 20% in terms of mol% based on the monomer amount of the polymer forming the film.

  The total solid content concentration contained in the composition for forming an etching stopper film of the present invention is preferably 0.1 to 50% by mass, more preferably 0.5 to 15% by mass, and particularly preferably 1 to 10%. % By mass.

The composition for forming an etching stopper film of the present invention preferably has a sufficiently low metal content as an impurity. The metal concentration in the composition can be measured with high sensitivity by the ICP-MS method, and the metal content other than the transition metal in that case is preferably 30 ppm or less, more preferably 3 ppm or less, and particularly preferably 300 ppb or less. . In addition, the transition metal has a high catalytic ability to promote oxidation, and from the viewpoint of increasing the dielectric constant of the film obtained in the present invention by an oxidation reaction in the prebaking and thermosetting processes, the content is preferably smaller. Preferably it is 10 ppm or less, More preferably, it is 1 ppm or less, Most preferably, it is 100 ppb or less.
The metal concentration of the composition for forming an etching stopper film can also be evaluated by performing total reflection fluorescent X-ray measurement on a coating film obtained from the composition of the present invention. When W line is used as the X-ray source, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pd can be observed as metal elements, each of which is 100 × 10 ¹⁰ cm ⁻² or less. Is more preferably 50 × 10 ¹⁰ cm ⁻² or less, and particularly preferably 10 × 10 ¹⁰ cm ⁻² or less. Moreover, Br which is halogen can also be observed, and the residual amount is preferably 10000 × 10 ¹⁰ cm ⁻² or less, more preferably 1000 × 10 ¹⁰ cm ⁻² or less, and particularly preferably 400 × 10 ¹⁰ cm ⁻² or less. is there. Further, although Cl can be observed as halogen, the remaining amount is preferably 100 × 10 ¹⁰ cm ⁻² or less, more preferably 50 × 10 ¹⁰ cm ⁻² or less from the viewpoint of damaging the CVD apparatus, the etching apparatus, and the like. Particularly preferably, it is 10 × 10 ¹⁰ cm ⁻² or less.

  From the composition for forming an etching stopper film according to the present invention, a coating film is formed by applying a solvent to the substrate by applying a spin coating method, a roller coating method, a dip coating method, a scanning method or the like, and then removing the solvent by a heat treatment. Can be formed. As a method of applying to the substrate, a spin coating method or a scanning method is preferable. Particularly preferred is the spin coating method. For spin coating, commercially available equipment can be used. For example, the clean track series (manufactured by Tokyo Electron), D-Spin series (manufactured by Dainippon Screen), SS series or CS series (manufactured by Tokyo Ohka Kogyo) can be preferably used. The spin coating conditions may be any rotational speed, but from the viewpoint of in-plane uniformity of the film, a rotational speed of about 1300 rpm is preferable for a 300 mm silicon substrate. In addition, the composition solution discharging method may be either dynamic discharge in which the composition solution is discharged onto a rotating substrate or static discharge in which the composition solution is discharged onto a stationary substrate. From the viewpoint of performance, dynamic ejection is preferable. Further, from the viewpoint of suppressing the consumption of the composition, it is also possible to use a method in which only the main solvent of the composition is preliminarily ejected onto the substrate to form a liquid film, and then the composition is ejected from there. it can. The spin coating time is not particularly limited, but is preferably within 180 seconds from the viewpoint of throughput. Further, from the viewpoint of transporting the substrate, it is also preferable to perform processing (edge rinse, back rinse) so as not to leave the film at the edge portion of the substrate. The heat treatment method is not particularly limited, but generally used hot plate heating, heating method using a furnace, light irradiation heating using a xenon lamp by RTP (Rapid Thermal Processor), etc. are applied. Can do. A heating method using hot plate heating or furnace is preferable. A commercially available device can be preferably used as the hot plate, and the clean track series (manufactured by Tokyo Electron), D-Spin series (manufactured by Dainippon Screen), SS series or CS series (manufactured by Tokyo Ohka Kogyo) can be preferably used. As the furnace, α series (manufactured by Tokyo Electron) and the like can be preferably used.

  It is particularly preferable that the hydrosilylated polymer (A) contained in the composition for forming an etching stopper film of the present invention is cured by heat treatment after coating on the substrate. For example, a polymerization reaction during post-heating of the carbon triple bond or double bond remaining in the hydrosilylated polymer (A) can be used. The conditions for this post-heat treatment are preferably 100 to 450 ° C., more preferably 200 to 420 ° C., particularly preferably 350 to 400 ° C., preferably 1 minute to 2 hours, more preferably 10 minutes to 1.5 ° C. Time, particularly preferably in the range of 30 minutes to 1 hour. The post-heating treatment may be performed in several times. Further, this post-heating is particularly preferably performed in a nitrogen atmosphere in order to prevent thermal oxidation by oxygen.

Moreover, in this invention, you may make it harden | cure by causing the polymerization reaction of the carbon triple bond or double bond which remain | survives in a polymer by irradiating a high energy ray instead of heat processing. Examples of high energy rays include electron beams, ultraviolet rays, and X-rays, but are not particularly limited to these methods.
The energy when an electron beam is used as the high energy beam is preferably 0 to 50 keV, more preferably 0 to 30 keV, and particularly preferably 0 to 20 keV. The total dose of the electron beam is preferably 0 to 5 μC / cm ² , more preferably 0 to ² μC / cm ² , and particularly preferably 0 to 1 μC / cm ² . The substrate temperature at the time of irradiation with an electron beam is preferably 0 to 450 ° C, more preferably 0 to 400 ° C, and particularly preferably 0 to 350 ° C. The pressure is preferably 0 to 133 kPa, more preferably 0 to 60 kPa, and particularly preferably 0 to 20 kPa. From the viewpoint of preventing oxidation of the polymer of the present invention, the atmosphere around the substrate is preferably an inert atmosphere such as Ar, He, or nitrogen. Further, a gas such as oxygen, hydrocarbon, or ammonia may be added for the purpose of reaction with plasma, electromagnetic waves, or chemical species generated by interaction with an electron beam. The electron beam irradiation in the present invention may be performed a plurality of times. In this case, the electron beam irradiation conditions need not be the same each time, and may be performed under different conditions each time.

Ultraviolet rays may be used as the high energy rays. The irradiation wavelength region when ultraviolet rays are used is preferably 160 to 400 nm, and the output is preferably 0.1 to 2000 mWcm ⁻² immediately above the substrate. The substrate temperature at the time of ultraviolet irradiation is preferably 250 to 450 ° C., more preferably 250 to 400 ° C., and particularly preferably 250 to 350 ° C. From the viewpoint of preventing oxidation of the polymer of the present invention, the atmosphere around the substrate is preferably an inert atmosphere such as Ar, He, or nitrogen. Further, the pressure at that time is preferably 0 to 133 kPa.

  The following examples illustrate the invention and are not intended to limit its scope.

<Synthesis Example of Hydrosilylated Polymers (A-1) to (A-5)>
Pentacyclo [9.5.1.1 ^3,9 . 1 ^5,15 . 1 ^7,13] octasiloxane 1.0 g (2.36 mmol), 1,3-bis (phenylethynyl) benzene 0.656 g (2.36 mmol) was dissolved in toluene 240 ml, platinum divinyl siloxane (xylene solution, Huls PCO72 ) Was added and reacted at room temperature for 3 hours to obtain a polymer (A-1) having a weight average molecular weight of 25,000. The hydrosilylation polymer (A) used in the following examples in the same manner as in the synthesis examples except that the amount of 1,3-bis (phenylethynyl) benzene as the diyne compound and the type of diyne compound were changed. -2) to (A-5) were obtained. Table 1 summarizes the weight average molecular weight of the hydrosilylated polymer obtained and the measured carbon content (mass%) determined by elemental analysis.

<Preparation of composition for forming etching stopper film>
Each polymer obtained in the above synthesis example was completely dissolved in a solvent so as to have a solid content of 10% by mass to prepare a coating solution. This coating solution was filtered through a filter having a pore size of 0.01 μm to obtain a coating solution for forming an etching stopper film.

<Synthesis example of organic polymer for interlayer insulating film formation>
3,3 '-(oxydi-1,4-phenylene) bis (2,4,5-triphenylcyclopentadienone) (782.4 g, 1.0 mol), and 1,3,5-tris (phenylethynyl) benzene (378.2 g (1.00 mol)) was dissolved in 4 liters of γ-butyrolactone, and this solution was added to the flask. The flask was purged with nitrogen, and the solution was heated and stirred at 200 ° C. After heating for 12 hours, the solution cooled to room temperature was added to 5 liters of ethanol. As the powdered solid obtained by precipitation at this time, 3,3 '-(oxydi-1,4-phenylene) bis (2,4,5-triphenylcyclopentadienone) and 1,3,5-tris (phenyl) A polymer (P) was obtained as a Diels-Alder reactant of ethynyl) benzene.

<Preparation of composition for forming organic interlayer insulating film>
The polymer (P) obtained in the organic polymer synthesis example was completely dissolved in cyclohexanone so as to have a solid content of 5% by mass. The solution was filtered through a filter having a pore size of 0.01 μm to obtain a coating solution for forming an organic polymer insulating film (hereinafter referred to as “coating solution-O”).

<Measurement of relative permittivity>
A coating film was formed on an 8-inch bare silicon wafer having a substrate resistance value of 7 Ω / cm by spin coating from various etching stopper coating solutions prepared as described above. The coated film was baked at 110 ° C. for 60 seconds, followed by 200 ° C. for 60 seconds, and then baked for 1 hour in a 400 ° C. clean oven purged with nitrogen to obtain a coated film having a thickness of 100 nm. The relative dielectric constant of the obtained film was calculated from the capacitance value at 1 MHz using a mercury probe manufactured by Four Dimensions and an HP4285ALCR meter manufactured by Yokogawa Hewlett-Packard.

<Evaluation of etching selectivity>
A coating film was formed on a bare silicon wafer by spin coating from various etching stopper coating solutions prepared as described above. The coated film was baked at 110 ° C. for 60 seconds, then at 200 ° C. for 60 seconds, and then baked in a 400 ° C. clean oven purged with nitrogen for 1 hour to obtain an etching stopper film having a thickness of 100 nm.

The obtained etching stopper film was etched under the etching conditions of the inorganic interlayer insulating film (gas species mainly composed of fluorocarbon, hereinafter referred to as “inorganic etching conditions”), and the film thickness etched per unit time FT _A was measured with a film thickness meter. Also in the inorganic-based etching conditions, etching of PECVD-SiOC film was measured thickness FT _B etched per unit time, the film thickness meter. At this time, FT _B / FT _A was set to an etching selectivity _A under inorganic etching conditions.

Further, the obtained etching stopper film is etched under the etching conditions of the organic interlayer insulating film (gas species mainly composed of ammonia, hereinafter referred to as “organic etching conditions”), and is etched per unit time. the thickness FT _C was measured by a film thickness meter. At the same organic-based etching conditions, etching of organic polymer interlayer insulating film obtained from the "coating solution -O" described above, was measured thickness FT _D etched per unit time, the film thickness meter. At this time, (FT _D / FT _C ) was set as an etching selectivity B under organic etching conditions.

  The evaluation results are summarized in Table 1 below.

  The film dielectric constants of SiN, SiC, SiCN, etc. formed by the plasma CVD method are about 7, 3-4, and 5-6, respectively. As shown in Table 1, the composition for forming an etching stopper film of the present invention is shown in Table 1. It can be seen that the etching stopper film produced has a low relative dielectric constant of 3 or less and has a sufficient etching selectivity with both the inorganic interlayer insulating film and the organic interlayer insulating film.

Claims (4)

Etching stopper film forming composition comprising hydrosilated polymer (A) obtained by reaction with hydridosilsesquioxane represented by the following general formula (1) and polyyne compound represented by the following general formula (2) object.
(HSiO _3/2 ) _n (R ¹ SiO _3/2 ) _m (1)
R ′ (— C≡C—R ² ) _k (2)
In the general formula (1), R ¹ represents a monovalent organic group.
n represents an integer of 1 to 20, and m represents an integer of 0 to 19. N + m is an integer of 4 to 20.
In the general formula (2), R ² represents a monovalent organic group, and R ′ represents a k-valent organic group.
k represents an integer selected from 1 to 6.   The composition for forming an etching stopper film according to claim 1, wherein the carbon content of the hydrosilylated polymer (A) is 55% by mass to 85% by mass.   A film formed from the composition for forming an etching stopper film according to claim 1.   An electronic device comprising the film according to claim 3.