TW200922976A - Insulating film - Google Patents

Abstract

Providing a insulating film, which may form a interlayer insulating film suitable for semiconductor device or the like with proper and average thickness, with good dielectric constant, Young's modulus and other film properties. Characterized in that the insulating film is formed by forming a film conformation on a substrate then hardening the film by the irradiation of UV light, wherein the film conformation comprising a polymer compound polymerized by a cage sequisiloxane compound having 2 or more unsaturated groups as substitution group and a polymerization initiator.

Description

[Technical Field] The present invention relates to an insulating film of a semiconductor element, and more particularly to an insulating film in a semiconductor element or the like, which may form a coating film having a suitable uniform thickness. And it has superior insulation properties. [Prior Art] It is known that a film used as an insulating film or an optical application is a cerium oxide (SiO 2 ) film formed by a vacuum process such as a vapor phase epitaxy (CVD) method. Further, in recent years, for the purpose of forming a more uniform interlayer insulating film, a hydrolyzed product of a tetraalkoxydecane which is a so-called S 0 G (S pi η η n G 1 ass: spin-on glass method) film is used as a hydrolysis product. The coating type insulating film of the main component is used in a manner to be used. In addition, an interlayer insulating film having a low dielectric constant has been developed, and the organic component such as organic SOG is used as a main component in accordance with the high integration of semiconductor elements and the like. However, even if it is a CVD-Si 2 film exhibiting the lowest dielectric constant among the inorganic material films, the specific dielectric constant is about 4. In addition, the specific dielectric constant of the 3:10? film which is recently discussed as a low dielectric constant <:¥0 film is about 3.3 to 3 · 5 , but the film has high hygroscopicity and is used during use. The problem of a rise in dielectric constant. In such a case, as a method of insulating film material having excellent insulating properties, heat resistance, and durability, a conventional method is to add a high boiling point solvent or a thermally decomposable compound to an organic polyoxonium to form pores and reduce dielectric properties. constant. However, in the case of the above porous film, although the dielectric constant property is lowered by the porosity, the mechanical strength is also lowered, and the dielectric constant of 200922976 due to moisture absorption is increased. Further, since voids which are connected to each other are formed, the copper used for wiring is diffused to the insulating film or the like. In addition, it has been conventionally known to apply a solution in which a low molecular cage compound is added to an organic polymer to obtain a low refractive index and low density film (see Patent Document 1). However, in the method of adding a cage-type compound monomer, there is a problem that not only the effect of reducing the refractive index and the dielectric constant is insufficient, but also the coating surface is deteriorated or the film at the time of sintering is reduced to be large. Patent Document 1: Japanese Patent Laid-Open Publication No. Hei. No. 2000-A No. 3-8 8 8 1 SUMMARY OF INVENTION Technical Problem Accordingly, an object of the present invention is to provide an insulating film for solving the above The insulating film of the problem, more specifically, is suitable for use as an interlayer insulating film in a semiconductor element or the like, and it is possible to form a film having a suitable uniform thickness, and has a film property superior in dielectric constant, Young's modulus, and the like. Technical Solution to Problem The inventors of the present invention found that the above problems were solved by the following means: (1) An insulating film of a semiconductor device, characterized in that a polymer compound obtained by polymerizing a cage type sesquiterpoxide compound having two or more unsaturated groups as a substituent and a polymerization initiation are formed on a substrate After the film structure of the agent, it is formed by hardening the film by ultraviolet irradiation. (2) The insulating film of the semiconductor device of the above (1) is characterized in that the polymerization initiator is an azo compound. (3) The insulating film of the semiconductor device of the above (1) is characterized in that it is 15% by mass or less of the unreacted cage type sesquioxane 200922976 compound with respect to the solid content in the film structure. (4) The insulation of the semiconductor element disclosed in the above (1) further contains an organic compound having a thermal decomposition temperature of 300 ° C in the film structure. (5) The semiconductor element of the above (4) is exposed to ultraviolet light, and further cured at a temperature of 450 ° C or less. [Effects of the Invention] According to the present invention, it is possible to form a film uniformity, a low dielectric constant, and a Young's modulus which are suitable as a low refractive index film in a semiconductive interlayer insulating film or an optical member. EMBODIMENT OF THE INVENTION In the following, the insulating film of the present invention is a film structure of a polymer compound and a polymerization initiator which are formed by forming a cage-type sesquiterpene oxide having one or more unsaturated groups as a substituent on a substrate. The semiconductor element formed by hardening the film by external irradiation is used in the insulating film of the present invention, and a polymer having a cage-type sesquiterpoxide compound having two substituents is used. The so-called having two or more unsaturations The base is a substituted methane oxide compound (hereinafter, also referred to as compound (I)): has m RSi (0Q5) 3 units (m system means ί R represents a separate non-hydrolyzable group, and R, to ethylene a unit or a acetylene group), each of which has a single film, and is characterized by a thermally decomposable film which is characterized in that it is used for heating a film or the like at a temperature, and has a superior film containing two After the compound is polymerized, 'by the violet insulating film. The above unsaturated group is used as a cage half of the molecular group, for example, it can be listed as an integer of ～16, and two of the two groups contain the oxygen atom in the position 200922976. The other unit 'forms a compound having a cage structure (hereinafter, also referred to as a compound (Γ)). From the viewpoint of a dielectric constant reduction effect, for example, m in the compound (Γ) is preferably 8, 10, 12, 14, 1 6 'based on the point of view of acquisition, the further step is 8, 10, 12. Here, the so-called cage structure refers to the following molecules: the volume system is formed according to the atoms bonded by covalent bonding. As determined by a plurality of loops, the point within the volume does not pass through the loop and cannot leave the volume.

R is a non-hydrolyzable group which is independent of each other. When the non-hydrolyzable group is exposed to 1 equivalent of neutral water at room temperature for 1 hour, a residue of 95% or more remains. It is 99% or more. At least two of R are groups containing a vinyl group or an ethynyl group. Examples of the non-hydrolyzable group of R include an alkyl group (methyl group, a third butyl group, a cyclopentyl group, a cyclohexyl group, etc.), an aryl group (phenyl group, 1-naphthyl group, 2-naphthyl group, etc.). Ethylene, ethynyl, propyl, trityloxy (dimethyl alkoxy, diethyl alkoxy, tert-butyldimethylalkoxy) and the like. The group represented by R is preferably a group of at least two or ethynyl groups, and R is bonded to at least two of which are vinyl groups having a vinyl group or an ethynyl group. The group represented by R is preferably a ruthenium atom having a vinyl group or an ethynyl group which is directly or divalently bonded. The two-valent linkage can be listed as: - [C ( R1 1 )

-CO - 0 -N ( R'3 ) —, an S, a 0 *""" based on the two-valent link. Methyl, ethyl or phenyl is preferably -[C(R 1 1 ) si ( R14) ( R15 ) —, and any combination thereof (R11 to R15 represent each independently hydrogen atom; k represents 1~) An integer of 6.) 'Where' is (R12)] k- ' - 0- ' - 〇- Si(R14) 200922976 (R15) — or any combination of the two-valent linking groups of such groups. In the compound (I), the vinyl group or the ethynyl group is preferably R directly bonded to the bonded ruthenium atom. Among the R in the compound (I), at least two vinyl groups are more preferably directly bonded to the ruthenium atom to which R is bonded, and at least half of R in the compound (I) is a vinyl group, particularly all R Particularly ideal for vinyl. Specific examples of the compound (I) include, for example, the following compounds, but are not limited to the compound of the temple.

-10- 200922976 (I-a) (I,b)

-11 - 200922976 (I-d)

-12- 200922976

200922976 (Η) a ο-

Si- D R R w \ί \κ° Si—O—Si I I 〇 o o 1. I -Si^-O—Si, i 'X R ^ R \ -0—--s

R

R R= Ό—Si (I*k) r

Si: \? V Si—O—Si H3C\ /CH3 〇 o o

Si- , by an o-έΐ, I I R R -〇- -Si R-

R

R (1·1) n

St-O--Si r\ y Si—O—Si A 1 I 〇 o o o I I Sj~-p—Si^ 〆 I I 〇vR \

H3c h2 \/C\„/SIH CH3 R= R/si~~TR h2c •Q· sCH2 H3C~Si-CH3 The compound (I) can be synthesized by using a commercially available product or by a method known in the following. 14- 200922976 The R in the compound (I) of the present invention is preferably also a group represented by the following formula (丨ί ), in which case a compound which can be obtained by the following formula (丨丨) It is synthesized by reacting with a compound represented by the following formula (IV): (R1) 3 - Si - Ο - ( II ) [MO - Si(〇0,5) 3]m ( III) (R1 ) 3 - Si-C (IV) The compound of the formula (III) can be synthesized, for example, according to the method disclosed in Angew. Chem. Int. Ed. Engl. 1997, 36, No. 7, 743-745, etc. In the formula, R1 represents an independent non-hydrolyzable group, and specific examples of the non-hydrolyzable group represented by R 1 include an alkyl 'aryl group, an ethylene group, an ethynyl group, etc. m and R1 systems It has the same meaning as the compound (Γ) and the formula (π). The lanthanide means a metal atom (for example, 'Na, K, Cu, Ni, η η ) or a pin cation (for example, tetramethylammonium). M is a multivalent metal In the case of a child, it means a plurality of Ο—S i ( 〇〇.5 ) 3 bonded to a polyvalent metal atom Μ. I / a compound of the formula (III) and a formula (IV) The reaction of the compound shown, for example, a compound represented by the formula (111) and a compound of the formula (111), wherein the number of Si-OM groups contained in the compound of the formula (111) is 1 to a mole of the formula (IV) The compound shown in the above is added to the solvent while stirring, usually at 0 to 180 ° C, for 1 to 20 hours. The solvent is preferably an organic solvent such as toluene, hexane or tetrahydrofuran (τ HF ). When a compound represented by the formula (111) and a compound of the formula (1 ν) are reacted with 200922976, a base such as triethylamine or b-butane may be added. The composition of the insulating film (hereinafter, also simply referred to as "the composition for forming an insulating film") may contain a plurality of different polymers of the compound (I). In this case, 'a copolymer which may be a plurality of different compounds (I)' may also be a mixture of homopolymers. In the case where the composition for forming an insulating film contains a copolymer composed of a plurality of different compounds (I), a mixture of two or more compounds (1 ') selected from m = 8, 10 and 12 is preferred. Copolymer. The polymer compound obtained by polymerizing the compound (I) contained in the composition for forming an insulating film may be a copolymer of a compound other than the compound (1). The compound used in this case is preferably a compound having a plurality of polymerizable carbon-carbon unsaturated bonds or SiH groups. Examples of preferred compounds include vinylnes, vinylses, phenylacetylenes, [(HSiOo.s) 3]8 and the like. The composition for forming an insulating film is a solution in which a polymer compound obtained by polymerizing the compound (1) and a polymerization initiator are dissolved in an organic solvent. In the solid content contained in the composition for forming an insulating film, the total amount of the polymer in which the compound (I) reacts with each other is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more. Preferably, it is 9.5 mass% or more. The larger the content in the solid component, the lower the density, the refractive index, and the lower the dielectric constant. The solid component referred to herein is a component which deducts a volatile component from the total component contained in the component. The volatile component also contains a component which is volatilized after being decomposed into a low molecular weight compound. Examples of the volatile component may be, for example, water, an organic solvent, a thermally decomposable polymer for pore formation, a thermally decomposable substituent, or the like. The component other than the polymer which reacts with the compound (1)' which is contained in the solid content of the composition for forming an insulating film, the compound (1)' contains the copolymer of the compound (I). A component other than the reactant of the compound (1), a nonvolatile additive, or the like. In order to form a film having a good coating surface shape and a small film reduction during sintering, the unreacted compound (I) in the solid content contained in the composition for forming an insulating film is preferably small. The compound (I) in the solid component is 15% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less. From the GPC pattern of the solid component contained in the composition for forming an insulating film, the Mw of the portion excluding the monomer of the compound (I) is preferably 30,000 to 210,000 ', more preferably 40,000 to 180,000'. 50,000 to 160,000. The polymer of the present invention preferably contains substantially no molecular weight of 300 r or more, and more preferably substantially does not contain, based on the solubility in the organic solvent, the filterability of the filter, and the surface of the coating film. The component having a molecular weight of 2,000,000 or more is preferably a component which does not substantially contain a molecular weight of 1,000,000 or more. In the solid content contained in the composition for forming an insulating film, 'the vinyl group or the ethyl group of the compound (I) is preferably 10 to 90 mol% unreacted, and more preferably 20 to 20%. 80 mol% remains unreacted and remains, preferably 30 to 70 mol% unreacted and remains. Further, in the reactant of the compound (1) in the composition for forming an insulating film, the polymerization initiator, the additive or the polymerization solvent may be 0. 1 to 4 0 -17 to 200922976 mass% bonded, preferably 〇.1 to 2 0% by mass, more preferably ο. 1 to i 0% by mass, preferably 0.1 to 5% by mass. In view of this, it can be quantified from the NMR spectrum of the composition or the like. In order to produce a composition for forming an insulating film, the reactant of the compound (I) is preferably produced by a polymerization reaction of carbon-carbon unsaturated bonds with each other. In particular, it is particularly preferred to dissolve the compound (I) in a solvent and to add a polymerization initiator to react a vinyl group or an ethynyl group. Any polymerization reaction can be used as a polymerization reaction, for example, radical polymerization, cationic polymerization, anionic polymerization, ring-opening polymerization, condensation polymerization, polyaddition, addition polymerization, transition metal catalyst polymerization, and the like. The compound (I) remaining at the end of the polymerization reaction is preferably 25% by mass or less, more preferably 20% by mass or less, and most preferably 15% by mass or less. When the conditions are met during the polymerization, it is possible to efficiently produce a film-forming composition which is excellent in the state of the coated surface and which has a small film reduction during sintering. The weight average molecular weight (M w ) of the polymer at the end of the polymerization reaction is more preferably from 30,000 to 160,000, still more preferably from 40,000 to 140,000, and most preferably from 50,000 to 120,000. The Ζ+1 average molecular weight (Μζ+1) of the polymer at the end of the polymerization reaction is preferably from 90,000 to 700,000, further preferably from 120,000 to 550,000, and most preferably from 150,000 to 400,000. The polymer at the end of the polymerization reaction preferably contains substantially no component having a molecular weight of 30 million or more, more preferably contains substantially no component having a molecular weight of 2,000,000 or more, and preferably does not contain a component having a molecular weight of 1,000,000 or more. . -18- 200922976 When the polymerization is carried out, if the molecular weight conditions are met, the composition for film formation can be prepared, which is soluble in organic solvents, and the filter has good filterability, low density, and can form a low medium. A film of electrical constant. In order to satisfy the above molecular weight conditions, the concentration of the compound (I) in the reaction at the time of polymerization is preferably 12% by mass or less. The concentration of the compound (I) is more preferably 10% by mass or less, still more preferably 8% by mass or less, and most preferably 6% by mass or less. From the viewpoint of productivity at the time of the reaction, the concentration of the compound (I) at the time of polymerization is more advantageous. In this sense, the concentration of the compound (Ϊ) during the polymerization is 0.1% by mass or more, and more preferably 1% by mass or more. In addition, after the compound (I) is polymerized, it is removed by filtration or centrifugation to remove high molecular weight components, and then purified by a column chromatography method, etc., and is also a composition for producing an insulating film. Good method. In particular, 'reprecipitation treatment is carried out on the solid matter produced by the polymerization reaction', and the low molecular weight component and the remaining compound (I) are removed to increase the Μη and reduce the amount of the remaining compound (I). A preferred method of forming a composition for an insulating film. The polymerization of the compound (I) is preferably carried out in the presence of a non-metal polymerization initiator. For example, it can be polymerized in the presence of a polymerization initiator which exhibits activity by free radicals such as carbon radicals or oxygen radicals upon heating. It is particularly preferable to use an organic peroxide or an organic azo compound as the polymerization initiator. The organic peroxide is preferably a peroxyketone such as Perhexa®, which is sold by Nippon Oil & Fat Co., Ltd., -19-200922976; peroxy ketals such as Perhexa TMH; and hydroperoxides such as Perbutyl®-69. Peroxyl dialkyls such as Percumyl D, Perbutyl C, and Perbutyl D; peroxydistillates such as Nyper BW; peroxy vinegars such as Perbutyl Z and Perbutyl L; and peroxydicarbonic acid such as Peroyl TCP Ester; peroxyorthoester, Luperox 11 sold by ARKEMA, and others. The organic azo compound is preferably an azonitrile compound such as V-30, V-40, V-59, V-60, V-65, V-70 sold by Nippon Wako Pure Chemical Industries, Ltd.; VA-080, VA-085, VA-086, VF-096, V Am- 1 1 0 'V Am- 1 1 1 and other azoamine compounds; VA-044, VA-061, etc. Aziridine compounds; azo compounds of V_50, VA-〇57, etc.; azoester compounds of V-601, V-401, etc.; 2,2-azobis(4-methoxy-2, 4-dimethylvaleronitrile) and the like. The polymerization initiator is preferably an organic azo compound based on the safety of the reagent itself and the molecular weight reproducibility of the polymerization reaction, and among them, V-601 or the like which does not bond a harmful cyano group in the polymer is preferable. A nitrogen ester compound. The 1 〇 hour half-life temperature of the polymerization initiator is preferably 1 〇〇 ° C or less. When the half-life temperature of 10 hours is 1 〇 〇 ° C or less, it is easy to carry out the reaction without stopping the polymerization initiator at the end of the reaction. The polymerization initiator of the present invention may be used singly or in combination of two or more. The polymerization initiator of the present invention is preferably used in an amount of 0.0001 to 2 mol, more preferably 0.003 to 1 mol, particularly preferably 0.001 to 0.5 mol, based on 1 mol of the monomer. The solvent used in the polymerization reaction may be any solvent as long as it can dissolve the compound (I) in the necessary concentration, and does not adversely affect the film properties formed by the obtained polymer. . For example, water, an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, an aromatic hydrocarbon solvent, a guanamine solvent, a halogen solvent, an aliphatic hydrocarbon solvent, or the like can be used. Among these solvents, more preferred solvents are ester solvents, among which are methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, amyl acetate, hexyl acetate, methyl propionate. Ethyl propionate, propylene glycol monomethyl ether acetate, γ-butyrolactone, methyl benzoate, and especially butyl acetate are particularly preferred. These solvents may be used singly or in combination of two or more. When the polymerization initiator is decomposed during the reaction, the reaction liquid can be heated to a necessary temperature. After the completion of the reaction, the organic solvent is preferably 75 ° C or more and 140 ° C or less in order to distill off the organic solvent. Examples of the method of adding the polymerization initiator include batch addition, batch addition, continuous addition, etc., and it is advantageous in terms of high component formation and film strength by using a small amount of a polymerization initiator to be added. Good for batch addition and continuous addition. 1. The most suitable conditions for the polymerization reaction in the present invention are different depending on the type of polymerization initiator, monomer, solvent, concentration, etc., and the internal temperature is preferably 〇t~200 °C. 4 0 °C ~ 1 70 °C, especially 7 0. (:~1 4 0. (: Particularly ideal; preferably 1 to 50 hours) more preferably 2 to 2 hours, especially in the range of 3 to 10 hours. In addition, 'to suppress the cause of oxygen The inactivation of the polymerization initiator is preferably carried out in an inert gas atmosphere (for example, nitrogen, argon, etc.) The oxygen concentration during the reaction is preferably 100 ppm or less, more preferably 50 ppm or less, particularly 20 ppm. In the case of producing a composition for forming an insulating film, the reaction liquid for carrying out the polymerization reaction of the compound (I) can be used as a composition for forming an insulating film, and it is preferably a solvent for distilling off the reaction. It is preferably used after concentration. Further, it is preferably used after the reprecipitation treatment. The method of concentrating is preferably heating and/or decompressing the reaction liquid by using a rotary evaporator, a distillation apparatus or a reaction apparatus for performing polymerization. The concentration of the reaction liquid during concentration is generally 〇 ° C ~ 1 80 ° C, preferably 10 ° C ~ 1 40 ° C, more preferably 20 ° C ~ 1 0 〇 ° C, most Good for 30 ° C ~ 60 ° C. The pressure during concentration is generally 〇.133Pa~lOOkP a, preferably, it is 1.33 Pa to 13.3 kPa, more preferably 1.33 Pa to 1.33 kPa, and the concentration of the solid component in the reaction liquid is preferably 10% by mass or more, more preferably, when the reaction liquid is concentrated. The composition for forming an insulating film in the present invention may contain a polymerization initiator, and the polymerization initiator in this case may be concentrated by concentrating it in an amount of 30% by mass or more. For example, an organic peroxide or an organic azo compound is particularly suitable. The organic peroxide is preferably a peroxy ketone such as PerhexaH sold by Nippon Oil & Fat Co., Ltd.; a peroxy ketal such as PerhexaTMH; Hydrogen peroxides such as H-69; peroxyl bases such as Percumyl D, Perbutyl C, and Perbutyl D; peroxydiesters such as Nyper BW; peroxy vinegars such as Perbutyl Z and Perbutyl L Peroxydicarbonate such as Peroyl TCP; diisobutyl butyl peroxide, cumene peroxy neodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, peroxydialdehyde Dibutyl carbonate, peroxy new Acid-1,1,3,3-tetramethyl ester, peroxydicarbon-22- 200922976 di(4-tributylchlorohexyl) acid, di(2-ethylhexyl)peroxydicarbonate, Third hexyl peroxy neodecanoate, tert-butyl peroxy neodecanoate, tert-butyl peroxynoxy neoheptanoate, third hexyl peroxytrimethylacetate, third peroxytrimethylacetate Butyl ester, peroxybis(3,5,5-trimethylhexyl), peroxydilaurate, 'peroxy-2-ethylhexanoic acid-1, 1 , 3 , 3 -tetramethyl Butyl ester, peroxydisuccinic acid, 2,5-dimethyl-2,5-di(peroxy-2-ethylhexyl)hexane, perhexyl peroxy-2-ethylhexanoate , peroxybis(4-methylbenzhydrazide), tert-butyl peroxy-2-ethylhexanoate, peroxydi(3-methylbenzhydrazide), peroxybenzoic acid (3-methyl) { 'benzamide}, benzophenone, peroxybenzhydryl, 1,1-di(peroxy-tert-butyl)-2-methylcyclohexane, 1,1-di (over Oxygen trihexyl)-3,3,5-trimethylcyclohexane, 1,1-di(peroxy-tert-hexyl)cyclohexane, 1,1-di(peroxy-tert-butyl)cyclohexane Alkane, 2,2-di(4,4·di(peroxy-tert-butyl)cyclohexyl Propane, perhexyl isopropyl monocarbonate, tert-butyl peroxymaleate, tert-butyl peroxy-3,5,5-trimethylhexanoate, third peroxylauric acid Butyl ester, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, third hexyl peroxybenzoate, 2,5-dimethyl-2,5 - gamma (perbenzoic acid) hexane, tert-butyl peroxyacetate, 2,2-bis(peroxybutylbutyl)butane, tert-butyl peroxybenzoate, 4,4- Di-n-butylperoxypivalate n-butyl ester, di(2-tert-butylperoxyisopropyl)benzene, dicumyl peroxide, peroxyditrihexyl, 2,5-dimethyl Benzyl-2,5-di(peroxybutylbutyl)hexane, peroxyth-tert-butyl cumyl, peroxydi-tert-butyl, hydroperoxide to methane, 2,5-dimethyl -2,5-di(peroxy-tert-butyl) _3_hexyne, hydroperoxydiisopropylbenzene, hydroperoxy-1,1,3,3-tetramethylbutyl, hydroperoxy Propylbenzene, hydroperoxy-tert-butyl, 2,3-dimethyl- 2,3-diphenylbutane, peroxy-2,4-dichlorobenzhydryl, peroxy-o-chlorobenzamide Base, peroxy-23- 200922976 p-chlorobenzene Mercapto, ginseng (peroxybutyl butyl) triple trap, peroxy neodecanoic acid-2,4,4-trimethylpentyl ester, peroxy-n-decanoic acid-α-isopropylphenyl ester, peroxy-2 _ethylhexanoic acid third amyl ester, peroxyisobutyric acid tert-butyl ester, peroxyhexahydroterephthalate di-t-butyl ester, peroxytrimethyl adipate di-t-butyl ester, peroxygen Di-3,3-methoxybutane dicarbonate, diisopropyl vine carbonate, dibutyl isopropyl peroxycarbonate, 1,6-bis(peroxycarbonyloxybutyl butyl) hexane, two Ethylene glycol bis(tert-butyl peroxycarbonate), perhexyl peroxy neodecanoate, Luperoxli sold by ARKEMA, and others. The organic azo compound is preferably an azonitrile compound such as V-30, V-40, V-59, V-60, V.65 or V-70 sold by Nippon Wako Pure Chemical Industries, Ltd.; VA_08〇, VA-085, VA-086, VF-096, VAm-1 10 'VAm-1 1 1 and other azo hydrazine compounds; VA-044, VA-061, etc. ; arsenazo compounds such as V·50 and VA_057; azoester compounds such as V-601; 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2.2-azobis(2·methylpropionitrile), 2,2·azobis(2,4-dimethylbutyronitrile ), 1,1_azobis(cyclohexyl-1-acetonitrile), 1-[(cyano-1-methylethyl)azo]carbamamine, 2,2-azobis{ 2-methyl-N-[ 1,1-bis(hydroxymethyl)-2-isoethyl]propanol}, 2,2-azobis[2-methyl-N-(2-di-butyl) Base) propionate], azobis(N-(2·propanyl-methylpropionamide)' 2.2-azobis(N-butyl-2-methacrylamide), 2,2 _Azobis(N_cyclohexyl-2-methylpropionamide), dihydrochloric acid-2,2-azobis[2-(2-imida) 2-yl)propane], dihydrate disulfate-2,2-azobis[2-(2-amido-2-yl)propyl] 'dihydrochloric acid_2,2-azo double{ 2_[ 1_ ( 2_ethyl)-2-imidazolyl-2-yl]propane}, 2,2-azobis[2-(2-imidazol-2-yl)propan-24- 200922976 alkane], 2-, 2-azobis(1-imino-1-pyrrolidinyl-2-methylpropane) hydrochloride, 2-,2-azobis(2-methylpropionamidine dihydrochloride) ), tetrahydrate-2,2-azobis[N-(2-carboxyethyl)-2-methylpropanthene], dimethyl-2,2-azobis(2-methylpropionate) ), 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(2,4,4-trimethylpentane), etc. Based on the safety and polymerization of the reagent itself The molecular weight reproducibility, the polymerization initiator is preferably an organic azo compound, and among them, an azo ester compound such as V-601 which does not bond a harmful cyano group in the polymer is preferable. The radical generating agent, colloidal cerium oxide, surfactant, decane may also be used in the range of properties (heat resistance, dielectric constant, mechanical strength, coating property, adhesion, etc.) of the obtained insulating film. An additive such as a mixture or a patch is added to the composition for forming an insulating film. In the present invention, any surfactant such as a nonionic surfactant, an anionic surfactant, or a cationic interface activity may be used. Further, examples of the agent and the like include a siloxane surfactant, a fluorine-containing surfactant, a polyalkylene oxide surfactant, and an acrylic surfactant. The surfactant used in the present invention may be one type or two or more types. The surfactant is preferably a decane-based surfactant, a nonionic surfactant, a fluorine-containing surfactant, or an acrylic surfactant, and particularly preferably a siloxane-based surfactant. The total amount of the film forming coating liquid is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.1% by mass or more and 0.5% by mass or less. In the present invention, the siloxane-based surfactant is a surfactant containing at least one s i atom. The oxoxane-based surfactant used in the present invention may be any siloxane-based surfactant, preferably a structure containing a ring of -25-200922976 oxyalkylene and dimethyloxane. In the present invention, each component is dissolved in a suitable solvent and applied to a carrier. Examples of the solvent which can be used include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclohexanone, butyrolactone, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether. , ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl carbonate, butyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethoxy Ethyl propyl propionate, Ν-methylpyrrolidone, hydrazine, hydrazine-dimethylformamide, tetrahydrofuran, methyl isobutyl ketone, xylene, mesitylene, diisopropylbenzene. The solution obtained by dissolving the composition for forming an insulating film in a suitable solvent is also included in the range of the composition for forming an insulating film. The total solid content concentration in the solution of the present invention is preferably from 1 to 30% by mass, and is appropriately adjusted depending on the purpose of use. When the total solid content concentration of the composition is 1 to 3 〇 mass%, the film thickness of the coating film is in an appropriate range. The preservation stability of the coating liquid is also superior. Further, the composition for forming an insulating film may further contain a thermally decomposable organic compound having a thermal decomposition temperature of 300 ° C or higher. The thermally decomposable organic compound may, for example, be a pore forming factor or a compound which accelerates heat hardening as described later. In the insulating film forming composition, the pore forming factor can be used to make the film porous, and a low dielectric constant can be expected. The pore forming factor which is an additive of the pore-forming agent is not particularly limited, and a non-metal compound is suitably used, and the solubility in the solvent used for the coating liquid for film formation and the compatibility with the polymer of the present invention are -26- 200922976 Necessary. The pore former can also use a polymer. The polymer which can be used as a pore former can be, for example, a polyvinyl aromatic compound (polystyrene, polyvinylpyridine, halogenated polyvinyl aromatic compound, etc.), polyacrylonitrile, polyalkylene oxide (poly) Ethylene oxide and polypropylene oxide, etc.). Polyethylene, polylactic acid, polyalkylene oxide, polycaprolactone, polycaprolactam, polyurethane resin, polymethyl acrylate (polymethyl methacrylate, etc.) or polymethacrylic acid 'polyacrylic acid Ester (polymethacrylate, etc.) with polyacrylic acid, polydiene (polybutadiene and polyisoprene), polyvinyl chloride, polyacetal, and amine crown alkylene oxide, in addition, polyphenylene ether, Poly(dimethyloxane), polytetrahydrofuran, polycyclohexylethylene, polyethyloxazoline, polyvinylpyridine, polycaprolactone, and the like. In particular, polystyrene can be suitably used as a pore former. Further, the boiling point or decomposition temperature of the pore forming agent is preferably from 100 to 500 ° C. More preferably from 2 0 0 to 4 50 ° C, particularly preferably from 2 5 0 to 400 ° C. The molecular weight is preferably from 200 to 50,000, more preferably from 300 to 1 Torr, and particularly preferably from 400 to 5,000 °c. The amount of the pore-forming agent added is expressed by mass% with respect to the polymer forming the film, preferably from 0.5 to 75%, more preferably from 0 to 5 to 30%, particularly preferably from 1% to 2%. In addition, the pore formation factor may contain a decomposable group in the polymer, and its decomposition temperature is preferably from 10 to 50 (TC, more preferably from 200 to 4500 °C, especially 2 5 〇~400°C is particularly desirable. The content of the 'dispersion group' relative to the polymer forming the film is expressed in mol%, preferably 0.5 to 75% 'more preferably 0.5 to 30%, especially It is preferable that the composition for film formation of the present invention is used for film formation by filtering through a filter membrane to remove insoluble matter, gelatinous component, and the like. The pore diameter of the membrane is preferably 0.001 to 0.2 μm, the pore diameter is more preferably 0.0 05 to 0.05 μπι, and the pore diameter is preferably 〇·〇〇5 to 〇.〇3 μιη. The material of the membrane is preferably PTFE, polyethylene, nylon. More preferably, the film of the present invention can be coated with a film forming composition by any method such as a spin coating method, a roll coating method, a dip coating method, a casting method, a spray method, or a rod coating method. After heating on a wafer such as a wafer, a Si 〇 2 wafer, a Si Ν wafer, a glass, or a plastic film, if necessary, using heating The method of applying the solvent to the substrate is preferably a method of performing a spin coating method or a casting method. Particularly, a method using a spin coating method is particularly preferable. From the viewpoint of substrate transfer, it is preferred. In order to perform a process (edge rinsing, backside rinsing) in which the film at the edge portion of the substrate is not left. The film thickness at the time of forming the insulating film is a dry film thickness capable of forming a thickness of about 0.05 to 1.5 μm. The secondary coating can form a thickness. The coating film of the present invention is cured by irradiating ultraviolet rays to cause polymerization of a vinyl group or an ethynyl group remaining in the polymer after being coated on the substrate. The irradiation wavelength is preferably in the field of ultraviolet rays. For i 90~400nm' directly above the substrate, the output is preferably 〇1~2〇〇〇inw/cin-2. The substrate temperature during ultraviolet irradiation is preferably 2 5 0~4 5 0 °C, Preferably, it is particularly suitable for preventing oxidation of the polymer of the present invention from the viewpoint of 2 5 0 to 4 0 0 ° C. Nitrogen In addition, the pressure at this time is preferably 〇~13 3kPa ° -28- 200922976. It can be simultaneously subjected to heat treatment and high-energy line irradiation treatment. Alternatively, it can be hardened in sequence. Preferably, it is 1 00~450 ° C, more preferably 200~420 ° C, especially 350~400 ° C, preferably 1 'minute ~ 2 hours' is better for 10 minutes ~ 1.5 hours, especially 30 minutes ~ In the range of 1 hour, the heat treatment may be carried out in several stages. More specifically, for example, a composition for forming an insulating film is applied onto a substrate (usually a substrate having metal wiring) by a spin coating method. The preheating treatment is performed to dry the solvent, and then, by performing ultraviolet irradiation, an insulating film having a low dielectric constant can be formed. When the film of the present invention is used as an interlayer insulating film for a semiconductor, in the wiring structure, the wiring side surface may be a barrier layer for preventing metal migration, and the wiring or the upper surface and the bottom surface of the interlayer insulating film are prevented. The peeling at the time of CMP may have an etching stopper layer or the like in addition to the gap layer and the interlayer adhesion layer, and if necessary, another material may be further used to divide the layer of the interlayer insulating film into a plurality of layers. The insulating film of the present invention may be used in combination with other Si-containing insulating films or organic films to form a laminated structure. It is preferably used after laminating with a film of a smoke system. ^ The film-based copper wiring of the present invention can be etched for other purposes. The etching may be either wet etching or dry etching, preferably dry etching. Dry etching can be suitably carried out using any of an ammonia-based plasma or a fluorocarbon-based plasma. In the plasma, not only Ar but also a gas such as oxygen or nitrogen, hydrogen or helium can be used. Further, after the etching process, the photoresist used for processing or the like can be removed and ashed, and the residue at the time of ashing can be removed and washed. The film of the present invention can be subjected to C Μ P (chemical mechanical honing) in order to planarize the copper plating portion after copper wiring processing. c ΜP slurry (chemical liquid) can be suitably used as a commercially available slurry (for example, manufactured by FUJIMI, manufactured by RODEL-NITTA, manufactured by JSR, manufactured by Hitachi Hitachi Chemical Co., Ltd.). Further, the CMP apparatus is suitable for use in a commercially available apparatus (manufactured by APPLID MATERIALS, 曰本荏原, etc.). Further, in order to remove the slurry residue after CMP, it can be washed.

The film of the present invention can be used for a wide variety of purposes. For example, it is suitable as an insulating film for electronic devices such as LSI, System LSI, DRAM, SDRAM, RDRAM, and D-RDRAM, and electronic components such as multi-chip module multilayer wiring boards. In addition to the interlayer insulating film for semiconductors, the etching resist film, the surface protective film, and the buffer coating film, it can also be used as a protective film in L SI, an α-line shielding film, a coating film of a flexographic printing plate, and a coating film. It is used for the surface coating of a flexible copper plate, a solder resist film, a liquid crystal alignment film, and the like. Further, it can also be used as a surface protective film, an antireflection film, or a retardation film for an optical device. According to this method, an insulating film having a low dielectric constant can be obtained, that is, an insulating film having a specific dielectric constant of 2 /5 or less, preferably 2.3 or less, can be obtained. [Examples] Hereinafter, the present invention will be specifically described based on examples, and the scope of the present invention is not limited thereto. [Synthesis Example 1] An exemplary compound (I-d) (manufactured by Aldrich Co., Ltd.) was added to 80 g of butyl acetate. V-601 (1〇, manufactured by Wako Pure Chemical Industries, Ltd.), which is heated under reflux in a nitrogen stream (internal temperature 127. (:), and diluted with 4 m 1 of butyl acetate as a polymerization initiator. Hour half-life temperature 66. 〇) 5 mg solution, it takes 2 hours to drip in. After the end of the dropwise addition, add -30-200922976 heat reflux for 1 hour. Add 20 mg of 4-methoxyphenol of polymerization inhibitor, then cool to The mixture was concentrated to a weight of 2 g of the solution at room temperature, and 20 ml of methanol was added thereto, and the mixture was stirred for 1 hour, and then the solid was filtered and dried. The solid was dissolved in tetrahydrofuran, and the mixture was stirred while being dropped into water 1·8 m 1 After stirring for 1 hour, the supernatant liquid was discarded by decantation, and 10 ml of methanol was added. The solid matter was filtered and dried to obtain a solid form of .49 g. When the solid component was analyzed by GPC, the molecular weight was larger than that of the exemplary compound (Id). The component is Mw = 158,000, Mz+1 = ; 310,000, and Μη = 8.9 million. In the solid matter, the unreacted compound (Id) is 3% by mass or less. The component having a molecular weight of not more than 3,000,000 is not contained. Using heavy chloroform as a measuring solvent After forming a 1 H-NMR spectrum, proton peaks attributed to the alkyl group formed by vinyl polymerization were observed: the integral ratio of proton peaks belonging to the residual vinyl group = 48:52, and it was found that the vinyl groups were already Polymerization: 5 ml of propylene glycol methyl ether acetate was added to the composition 0.3 g, and the mixture was stirred at 40 ° C for 3 hours, and then uniformly dissolved. The membrane was filtered using a 0.2 μm pore size TEFLON (Teflon; registered trademark) filter. The composition for forming an insulating film A was obtained. From the weight of the remaining monomer and the weight of the additive, it was clearly found that the polymer in which the vinyl groups of the monomers reacted with each other was 70% by weight in the solid content in the composition. [Synthesis Example 2] An exemplified compound (Id) (manufactured by Aldrich Co., Ltd.) was added to 26.4 g of butyl acetate, and heated under reflux in a nitrogen stream (internal temperature: 127 ° C), and butyl acetate was used. 2 m 1 diluted with V. 60 1 (1 〇 hour half-life temperature 6 6 °C) manufactured by Nippon Pure Chemical Industries Co., Ltd. as a polymerization initiator. 200922976 1. 8 mg solution, which took 2 hours to drip in. After the end of the entry, 1 hour plus The mixture was heated to reflux. After adding 4 mg of 4-methoxyphenol as a polymerization inhibitor, it was cooled to room temperature, concentrated under reduced pressure to a solution weight of 2 g, and methanol (20 ml) was added. After stirring for 1 hour, the solid matter was filtered and dried. The mixture was dissolved in 15 ml of tetrahydrofuran, and while stirring, 5 ml of water was added dropwise thereto. After stirring for 1 hour, the upper supernatant liquid was discarded by decantation, and methanol 10 m 1 was added. The solid matter was filtered and dried to obtain a solid content of 0.60 g. When the solid content is analyzed by GPC, the component having a larger molecular weight than the exemplified compound (I-d) is Mn = 31,000, Mw = 18,000, and Mz+1 = 270,000. In the solid form, the unreacted compound (I-d) is 3% by mass or less. It does not contain components with a molecular weight of more than 30,000. Using heavy chloroform as a measuring solvent, the 1 H-NMR spectrum of the solid component was measured, and a proton peak attributed to the alkyl group formed by vinyl polymerization was observed: the proton peak attributed to the residual vinyl group = 42 : 5 8 The ratio, it is known that the vinyl groups have been polymerized with each other. 5 ml of propylene glycol methyl ether acetate was added to the composition of 〇3 g, and the mixture was stirred at 40 ° C for 3 hours, and then dissolved in a uniform manner. The filter film made of TEFLON (registered trademark) having a pore diameter of 0 μm was used to obtain an IJ insulating film-forming composition B. From the weight of the remaining monomer and the weight of the additive, it is clear that the polymer which has reacted with each other in the solid content in the composition is 7 〇 by weight or more. [Example 1] The following additives I to vi were added to the solutions obtained in the compositions A to B prepared in the above Synthesis Example by the spin coating method at a concentration ratio of 33% to the solid content of A to B. After coating on a 4 吋 sand wafer, the substrate was dried at 11 〇r on a hot plate of -32-200922976, and further subjected to any of the following processes (1) to (5) to obtain a coating film (film thickness 3 0). 0 nm ) ° (additive) I. WAK 山 sorbitol monooleate ' II · polyethylene glycol monostearate manufactured by WAKO III. Polyethylene oxide laurel made by WAKO Ethyl ether IV. Polyethylene oxide sorbitan monooleate V. Pluronic ΡΕ6400 f' from BASF Corporation VI. Pluronic PE1740 manufactured by BASF Corporation (film coating process) (1) Clean in a nitrogen atmosphere Heat in an oven at 35 ° C for 4 5 minutes. (2) A 222 nm ultraviolet light was irradiated for 30 minutes on a hot plate heated to 350 ° C in a nitrogen atmosphere using a USHIO electrical barrier Barrier discharge lamp. (3) Using a U S Η I Ο electric mechanism B a r r i e r (barrier) discharge lamp on a hot plate heated to 350 ° C in a nitrogen atmosphere, irradiating the ultraviolet of 2 2 2 n m

/ After light for 3 minutes, further in a clean oven in a nitrogen atmosphere, heat at 4500 °C for 45 minutes. (4) The UV light of 72 nm was irradiated for 10 minutes on a hot plate heated to 350 ° C in a nitrogen atmosphere using a USHIO electrical barrier Barrier discharge lamp. (5) On a hot plate heated to 35 ° C, in a nitrogen atmosphere, using a USHIO electrical barrier Barrier (discharge) discharge lamp, after irradiating 丨72 nm ultraviolet light for 10 minutes, further in a nitrogen oven clean oven Medium, at 40 (rc heating for 4 5 minutes. -33- 200922976 Using 'Mineral PROB by Dimensions Co., Ltd. (measuring temperature 25 ° C). Membrane reduction rate and refractive index system made by the company's spectroscopic ellipsometer (VASE The ionic root indenter (NANOINDENTER) is used to form the film on the quartz substrate, and the X of the absorption peak of 3% or more in the range of 300 to 600 nm is evaluated, and no absorption is observed. In the case of the case, the evaluation is ◦. The dielectric constant is determined by WOOLLAM. The mechanical strength is evaluated. The light is estimated, and the wavelength is found. The evaluation results are shown in Table 1-34-200922976 [Table 1] (Table 1) Evaluation result of composition A for insulating film composition Additive program refractive index permittivity Young's modulus GPa penetration A — (1) 1.333 2.16 4.0 〇A — (2) 1.35 2.5 7.2 〇A — ( 3) 1.342 2.35 7.9 〇A — (4) 1.344 2.51 11.5 〇A — (5) 1.334 2.52 11.2 〇AI (1) 1.415 2.45 4.2 〇AI (2) 1.452 2.51 4.8 〇AI (3) 1.410 2.48 5,8 〇AI (4) 1.321 2.04 7.5 〇AI (5) 1.321 2.03 7.8 〇A II (1) 1.416 2.51 4.6 〇A II (2) 1.442 2.42 4.3 〇A II (3) 1.411 2.38 6.0 〇A II (4) 1.322 2.07 7.4 〇A II (5) 1.322 2.06 7.6 〇A III (1) 1.481 2.61 3.5 〇A III (2) 1.442 2.42 4.3 〇A III (3) 1.445 2.23 6.2 〇A III (4) 1.321 2.06 6.8 〇A III (5) 1.322 2.06 11.4 〇A IV (1) 1.421 2.35 3.4 〇A IV (2) 1.435 2.41 4.2 〇A IV (3) 1.435 2.31 5.8 〇A IV (4) 1.321 2.10 8.1 〇A IV (5) 1.322 2.15 9.5 〇AV (1) 1.415 2.45 3.4 〇AV (2 1.425 2.415 4.1 〇AV (3) 1.440 2.35 5.5 〇AV (4) 1.330 2.12 5.9 〇AV (5) 1.325 2.14 6.5 〇A VI (1) 1.416 2.50 3.1 〇A VI (2) 1.424 2.38 6.7 〇A VI ( 3) 1.36 2,35 5.6 〇A VI (4) 1.325 2.10 6.4 〇A VI (5) 1.325 2.14 6.7 〇-35- 200922976 [Table 2] (Table 2) Composition of the evaluation result of the composition B for insulating film formation Additive program refractive index permittivity Young's modulus GPa penetration B — (1) 1.355 2.45 4.0 〇B — (2) 1.368 2.43 6.1 〇B — (3) 1.362 2.32 5.6 〇B — (4) 1.324 2.25 8.0 〇B — (5) 1.322 2.25 8.2 〇BI (1) 1.355 2.45 4.0 〇BI (2) 1.368 2.43 6.1 〇BI (3) 1.362 2.32 5.6 〇BI (4) 1.324 2.25 8.0 〇BI (5) 1.322 2.25 8.2 〇 B II (1) 1.374 2.55 3.1 〇B II (2) 1.368 2.44 6.2 〇B II (3) 1.345 2.30 6,5 〇B II (4) 1.323 2.20 8.1 〇B II (5) 1,321 2.15 8.2 〇B III ( 1) 1.45 2.55 3.5 〇B III (2) 1.356 2.40 5.8 〇B III (3) 1.320 2.35 6.4 〇B III (4) 1.324 2.19 7.5 〇B III (5) 1.321 2.14 8.0 〇B IV (1) 1.52 2.65 3.2 〇B IV (2) 1.38 2,55 4.5 〇B IV (3) 1.322 2.45 5.5 〇B IV (4) 1.322 2.09 6.5 〇B IV (5) 1.321 2.12 6.8 〇BV (1) 1.45 2.55 2.8 〇BV (2) 1.44 2.45 4.4 〇BV (3) 1.334 2.37 4.8 〇BV (4) 1.322 2.12 7.2 〇BV (5) 1.321 2.12 7.5 〇-36- 200922976 It is known from the results of Tables 1~2. When, the good electrical characteristics, and can be formed of optically transparent film. [Simple description of the diagram] and 〇 ^\\\ [Description of main component symbols] Μ 〇

> \ NS -37-

Claims (1)

200922976 X. Patent Application Range: 1. An insulating film for a semiconductor device, characterized in that it is formed on a substrate and formed by polymerizing a cage type sesquifer compound having two or more unsaturated groups as a substituent. After the membrane structure of the molecular compound and the polymerization initiator is formed, it is formed by hardening the film by ultraviolet irradiation. The insulating film of the semiconductor device of the first aspect of the invention, wherein the polymerization initiator is an azo compound, and the insulating film of the semiconductor device of claim 1, wherein the film is constructed in relation to the film. The unreacted cage type sesquifer compound compound having a solid content is 15% by mass or less. 4. The insulating film of the semiconductor device of claim 1, wherein the film structure further comprises a thermal decomposition temperature of 300. (The above-mentioned thermal decomposition-decomposable organic compound. 5) The insulating film of the semiconductor element according to the fourth aspect of the patent application, wherein, when irradiated with ultraviolet light, the film is further heated at 450 ° (the following temperature). -38- 200922976 VII. Designated representative map: (1) The representative representative of the case is: No. (2) The symbol of the symbol of the representative figure is simple: 200922976 8. If there is a chemical formula in this case, please reveal the best indication of the characteristics of the invention. Chemical formula: (I-a) (I-b) (I-c) ΊΙ Amendment page 200922976. η, V. Abstract: The object of the present invention is to provide an insulating film which is capable of forming a film having a suitable uniform thickness suitable for use as an interlayer insulating film in a semiconductor element or the like, and having a superior dielectric constant. Film properties such as Young's coefficient. The means for solving the problem is characterized in that a polymer compound and a polymerization initiator which are obtained by polymerizing a cage type sesquiterpoxide compound having two or more unsaturated groups as a substituent are formed on a substrate. After the film structure, the film is formed by curing the film by ultraviolet irradiation. Provided an insulating film, which may form an interlayer insulating film suitable for semiconductor device or the like with proper and average thickness, with good dielectric constant, Young's modulus and other film properties. Characterized in that the film is The formed by forming a film conformation on a substrate then hardening the film by the irradiation of UV light, wherein the film conformation comprises a polymer compound polymerized by a cage sequisiloxane compound having 2 or more unsaturated groups as a substitution group and a polymerization initiator.