TWI442186B - Composition for forming resist underlayer film, and method of forming dual damascene structures using the same - Google Patents

Description

Composition for photoresist underlayer film and method for forming dual damascene structure

The present invention relates to a composition for a photoresist underlayer film and a method of forming a dual damascene structure. More specifically, it relates to a photoresist base film which is well embedded in a through-hole, has good etching resistance, can be easily removed, and can form a photoresist base film having excellent pattern transfer performance. A composition, and a method of forming a dual damascene structure using the composition.

In the past, when an integrated circuit element or the like is manufactured, an organic film such as a photoresist film is formed on an inorganic film such as a lanthanide oxide film or an interlayer film, for example, by irradiation, development, and irradiation through radiation. A photoresist process (i.e., micro-etching) of a step of pattern transfer or the like forms a desired photoresist pattern on the organic film and the inorganic film. In this lithography process, a photoresist underlayer film having an organic film under the photoresist film is generally used. That is, after the photoresist underlayer film is formed in advance, a photoresist film is formed on the photoresist underlayer film.

The photoresist underlayer film can have a function of flattening a gap of a base substrate or a groove or the like, and a function of absorbing radiation reflected from the substrate to prevent halation of the pattern; and The function of a mask for fine processing of an inorganic film.

For the composition for a photoresist base film to form a photoresist base film having such a function, for example, a polymer having a terpene unit as a main component can be proposed (for example, Patent Documents 1 and 2).

In particular, there is a mask having a fine processing for making an inorganic film The function of the photoresist underlayer film, that is, the photoresist film having an etch resistance, has been studied for various polymers contained in the photoresist underlayer film, and has been proposed for etching resistance and polymer structure. Some empirical relationships.

For example, the Daxi et al. have proposed that the etching resistance can be evaluated by the following formula (i) of the so-called Great West parameter (for example, Non-Patent Document 1).

(i): NT/{NC-NO-(2×NX)} (However, in the above formula (i), the total number of atoms in the NT system, the number of carbon atoms in the NC system, the number of oxygen atoms in the NO system, and the number of halogen atoms in the NX system )

According to this Western parameter, when the parameter value is small, for example, the number of carbon atoms is large, and the number of oxygen atoms and the number of halogen atoms are small, and the photoresist film has good etching resistance.

Further, in the case of Daxi et al., it has been proposed to carry out the evaluation of plasma ashing (hereinafter, referred to as "ashing" by the above-mentioned Daxi parameter. Specifically, it has been proposed that when the value of the Daxi parameter is large, the processing speed that can be evaluated as plasma ashing is good (fast).

The resistive underlayer film is high in value (the ashing can be favorably ashed), for example, a photoresist base film formed of a composition containing a halogenated polyhydroxystyrene (for example, Patent Document 3).

[Patent Document 1] JP-A-2001-40293

[Patent Document 2] JP-A-2000-143937

[Patent Document 3] JP-A-2003-57828

[Non-Patent Document 1] J. Electrochem. Soc. 130, 143 (1983).

[Disclosure of the Invention]

The photoresist underlayer film formed by the compositions described in Patent Documents 1 and 2 is a photoresist base film having a low Western parameter and excellent etching resistance, but in the ashing, the Daxi parameter is too low, that is, ashing. It takes time (the processing speed of ashing is slow), and the ashing of the underlying film of the photoresist is caused by the problem of damage to the inorganic film formed under the photoresist underlying film.

Specifically, the inorganic film, in particular, a low dielectric insulating film (hereinafter sometimes referred to as "Low-k film") is used for ashing, and there is a problem that the effective dielectric constant increases. More specifically, In the formation of the photoresist pattern of the via first double damascene process, when the photoresist film filled in the through hole is removed, the Low-k film exposed to the periphery of the through hole is damaged by the ashing plasma. In some cases, the dielectric constant is increased, and if the effective dielectric constant is increased, the electrical characteristics of the manufactured integrated circuit components and the like are significantly deteriorated.

The photoresist underlayer film formed by the composition of Patent Document 3 has a high Western parameter and a high processing speed of plasma ashing. Therefore, it is difficult to damage the Low-k film by the ashing of the photoresist film, but the corrosion resistance is achieved. Insufficient engraving (the Daxi parameter is too high), it is difficult to form a high-precision photoresist pattern.

As described above, the photoresist underlayer film formed by the conventional composition for a photoresist base film has good etching resistance and good processing speed of plasma ashing, and both of them cannot coexist sufficiently, and it is desired to develop and form. The composition of the photoresist underlayer film of the photoresist film which is coexisting.

The present invention provides a light which can be well embedded in a through-hole, has good etching resistance, can be easily removed, and can form a pattern-extracting light, in view of the problems of the prior art. A composition for a photoresist underlayer film that blocks an underlayer film, and a method for forming a dual damascene structure using the composition.

The inventors of the present invention have found that the composition of the photoresist underlayer film having a nitrogen atom content of 10% by mass or more in the photoresist underlayer film formed by the specific conditions is obtained as a result of the intensive study. The above problem can be solved by the method of forming a dual damascene structure using the composition, and the present invention has been completed.

Specifically, the present invention provides a composition for the following photoresist substrate and a method for forming a dual damascene structure of the composition.

[1] A composition for a photoresist underlayer film which is applied to a substrate and dried by heating at 250 ° C for 60 seconds to form a photoresist substrate having a thickness of 300 nm, wherein the nitrogen atom in the photoresist underlayer film is formed. The content rate is 10% by mass or more.

[2] The composition for a photoresist base film according to the above [1], which comprises a resin containing a nitrogen atom and a solvent.

[3] The composition for a photoresist base film according to [2] above, wherein the resin contains 10 to 20% by mass of the nitrogen atom.

[4] The composition for a photoresist base film according to the above [2], wherein the resin contains at least one selected from the group consisting of structural units represented by the following formulas (1), (2), and (3).

[5] The composition for a photoresist base film according to the above [4], wherein the ratio of the total of the structural units represented by the above formulas (1), (2), and (3) contained in the resin is 10 to 50. quality%.

[6] The composition for a photoresist base film according to the above [4], wherein the resin further contains a structural unit represented by the following formula (4).

(In the above formula (4), R ¹ represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a hydroxyl group, a substituted hydroxyalkyl group having 1 to 6 carbon atoms, and a carbon number. 1 to 20 substitutable alkoxy group, 1 to 6 carbon atom-substituted alkylthio group, aralkylthio group or arylthio group, amine group, substituted alkyl group having 1 to 6 carbon atoms An amine group, an aralkylamino group or an arylamine group, a halogen atom, or a substitutable aryl group having 7 to 20 carbon atoms; x is an integer of 1 to 6, an integer of y is 0 to 2, and x is 2 or more. In time, the lines R ¹ may be the same or different, respectively.

[7] The composition for a photoresist base film according to the above [1], which further comprises at least one selected from the group consisting of an acid generator and a crosslinking agent.

[8] A method of forming a dual damascene structure, comprising: forming a photoresist pattern on a photoresist underlayer film formed by the composition for a photoresist underlayer film according to [1] above; a photoresist film as a mask, wherein the photoresist pattern of the photoresist film is transferred to the photoresist underlayer film by etching; and the light of the photoresist pattern transferred with the photoresist film is used. a step of transferring the photoresist pattern of the photoresist underlayer film on the low dielectric insulating film disposed under the photoresist underlayer film as a mask; and rotating the low dielectric insulating film After printing the aforementioned photoresist pattern of the photoresist underlayer film, the step of removing the photoresist underlayer film by plasma ashing is performed.

[9] The method for forming a dual damascene structure according to [8] above, wherein the gas used for the plasma ashing is a mixed gas of ammonia, nitrogen and hydrogen.

The composition for a photoresist base film of the present invention exhibits excellent etching resistance and can be easily removed by forming a through-hole, and can form a photoresist base film having excellent pattern transfer performance. The effect of the person.

According to the method for forming a dual damascene structure of the present invention, the composition for a photoresist base film of the present invention is used, and the composition for the photoresist underlayer film can be well embedded in the through hole, and has good corrosion resistance. Engraved, easy The ground removal is excellent, and the pattern transfer performance is excellent; therefore, the photoresist pattern is good, and the effect of forming a double damascene structure with low damage of the low dielectric insulating film can be exhibited.

(The best form for implementing the invention)

In the following, the best mode for carrying out the invention will be described. However, the present invention is not limited to the following embodiments, and the following embodiments are not limited by the scope of the present invention, and based on the general knowledge of those skilled in the art, Additions, modifications, etc., which are also included in the scope of the present invention, should be understood.

[1] Composition of photoresist underlayer film:

An embodiment of the composition for a photoresist base film of the present invention is applied to a substrate and dried by heating at 250 ° C for 60 seconds to form a photoresist substrate having a thickness of 300 nm, and the nitrogen in the formed photoresist film is formed. The content of the atom is 10% by mass or more.

In the composition for a photoresist base film of the present embodiment, the content of nitrogen atoms in the photoresist underlayer film formed under the above-described conditions is 10% by mass or more, and when etching (RIE processing), the photoresist is under the photoresist layer. The nitrogen atom contained in the film reacts with fluorine derived from an etching gas such as CF ₄ or C ₂ F _{5 to form a} nonvolatile ammonium fluoride or ammonium fluorosilicate. Then, it is considered that the etching resistance of the iridium resistive underlayer film can be improved by the blocking action of ammonium fluoride or ammonium fluorosilicate or the like. Further, it is considered that the ashing is caused by the nitrogen atoms in the photoresist underlayer film, and in the photoresist underlayer film, a volatile gas such as HCN or C ₂ N ₂ can be formed, so that the photoresist underlayer film can be easily removed. .

Further, in the photoresist underlayer film formed of the composition for a photoresist base film of the present embodiment, a photoresist film having a photoresist pattern is used as a mask, and a pattern is transferred on the low dielectric insulating film. When it has the etch resistance of the trend line according to the Great West parameter. However, when it is removed by plasma ashing, the trend line of the large West parameter is easily removed (the processing speed of plasma ashing is good). Therefore, it is difficult to cause damage to the low dielectric insulating film when the plasma is ashed. In this way, the photoresist underlayer film formed of the composition for a photoresist base film of the present embodiment can be easily removed by plasma ashing, and the etching resistance is good, and the pattern transfer performance is excellent. .

In the conventional photoresist layer underlayer film composition, the content of the nitrogen atom in the photoresist underlayer film formed by the above conditions is less than 10% by mass, and the photoresist underlayer film formed by the conventional composition for the photoresist underlayer film is used. Although it has been reported that the properties of either the etching resistance or the ease of removal are good (for example, Patent Document 3), the etching resistance is not good, and it is not easily removed by plasma ashing.

Moreover, according to the parameters of the Great West, in the improvement of the etching resistance and the processing speed of the plasma ashing, the number of carbon atoms, the number of oxygen atoms, and the number of halogen atoms in the photoresist underlayer film have been mainly proposed. The composition for the photoresist underlayer film is a method for lowering the Great West parameter (increasing the number of carbon atoms) in order to improve the etching resistance. Moreover, in order to increase the processing speed of plasma ashing, a method of increasing the parameters of the Great West (increasing the amount of oxygen atoms) is adopted. As described above, in the above-described conventional method, it is difficult to achieve both of the etching resistance and the processing speed of plasma ashing. (That is, the relationship between the etching resistance and the processing speed of plasma ashing is balanced). Therefore, the inventors have found that the specific nature of the nitrogen atom is noted. (a non-volatile gas is generated during etching, and a volatile gas is generated when the plasma is ashed), and the ratio is more than 10% by mass or more due to the nitrogen atom contained in the photoresist underlayer film. Both of the etching resistance and the processing speed of plasma ashing can be made good.

The composition for a photoresist base film of the present embodiment will be described in detail below.

The composition for a photoresist base film of the present embodiment is formed by coating the substrate on a substrate at a temperature of 250 ° C for 60 seconds and then having a thickness of 300 nm. The substrate used for the film is not particularly limited, and for example, a tantalum wafer, a tantalum oxide film, tantalum nitride or the like can be used. Further, the coating method of the composition for a photoresist base film is not particularly limited, but is preferably a spin coating method.

Specifically, the composition for a photoresist base film of the present embodiment (solid content: 10% by mass) is applied by spin coating on a substrate having a diameter of 8 inches, for example, by Tokyo Electron Co., Ltd. The "ACT 8" was dried at 180 ° C for 60 seconds, and then the crucible wafer was placed in contact with the hot plate, and dried on the hot plate at 250 ° C for 60 seconds to form a dry photoresist underlayer film having a thickness of 300 nm.

In the composition for a photoresist base film of the present embodiment, the photoresist base film formed by the above method contains 10% by mass or more of nitrogen atoms, preferably 10 to 50% by mass, more preferably 20 to 40% by mass. %By. When the content of the nitrogen atom is less than 10% by mass, a photoresist underlayer film having a good ashing treatment speed cannot be obtained. On the other hand, if it is 50% by mass or more, the content of carbon atoms in the photoresist underlayer film relatively decreases, so if it is based on the Darcy parameter, it may not be obtained. Full etch resistance. In the present specification, the "content ratio of nitrogen atoms" is a value measured by an organic element analyzer. For example, you can use J. An organic element analyzer manufactured by Science Corporation (trade name "CHN Coater JM10".

In the composition for a photoresist base film of the present embodiment, the content of the nitrogen atom in the photoresist base film formed under the above-described conditions is not particularly limited as long as it is 10% by mass or more, and the content (for example, the type of the resin) is not particularly limited. However, it is preferred to include a resin containing a nitrogen atom and a solvent.

[1-1] Resin containing nitrogen atom:

The resin containing the nitrogen atom in the composition for the photoresist base film of the present embodiment is not particularly limited as long as it contains a nitrogen atom, but it is preferable to contain a nitrogen atom of 10% by mass or more, and particularly preferably 15 More than mass%. When the content of the nitrogen atom in the resin is less than 10% by mass, a sufficient treatment speed in plasma ashing may not be obtained. In addition, if the nitrogen content in the photoresist underlayer film is 15% by mass or more, in addition to having a sufficient processing speed in plasma ashing, it can be generated by etching and is caused by a nitrogen atom. The advantage of non-volatile gas and greatly improved etching resistance.

The resin containing a nitrogen atom preferably has a weight average molecular weight of (Mw) of from 1,000 to 20,000, more preferably from 1,000 to 3,000. If the weight average molecular weight is less than 1,000, when the photoresist underlayer film is formed, the low molecular component will volatilize from the photoresist underlayer film and contaminate the coating device. In addition, if it is 3,000 or more, it is feared that the through-hole embedding property necessary for the double damascene structure process is lowered. also, If it is more than 20,000, it is feared that the through-hole embedding property necessary for the dual damascene structure process is further lowered. Here, in the present specification, the "weight average molecular weight" means a polystyrene-equivalent number average molecular weight obtained by gel permeation chromatography (GPC).

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (hereinafter sometimes referred to as "Mn") of the resin containing a nitrogen atom is preferably 3.0 or less. When the above Mw/Mn is 3.0 or more, the coating property is deteriorated. Here, the "number average molecular weight" in the present specification means a polystyrene-equivalent number average molecular weight obtained by gel permeation chromatography (GPC).

Further, Mw and Mn are specifically used in a high-speed GPC device (type "HLC-8120" manufactured by Tosoh Corporation) using a GPC column manufactured by Tosoh Co., Ltd. (trade name "G 2000 HXL"; two, "G 3000 HXL"; 1 piece, "G 4000 HXL"; 1), analyzed by gel permeation chromatography with monodisperse polystyrene as standard, with a flow rate of 1.0 ml/min, solvent tetrahydrofuran, and column temperature of 40 °C. (GPC) The value measured.

The resin containing a nitrogen atom may, for example, be an amine-based resin produced by a reaction with formaldehyde (a condensed resin such as urea resin, sulfur urea resin, guanamine resin, melamine resin, pulse resin, or urea). Melamine resin, urea-benzoguanamine resin, phenol-melamine resin, naphthol-melamine resin, benzoguanamine-melamine resin, aromatic polyamine-melamine resin, etc., aromatic amine - Formaldehyde resin (aniline resin, etc.), polyamide resin (for example, nylon 3, nylon 6, nylon 66, nylon 11, nylon 12, nylon MXD, 6, nylon) 4-6, nylon 6-10, nylon 6-11, nylon 6-12, nylon 6-66-610, etc. alone or copolymerized polyamine, substituted polyamine with methylol or alkoxymethyl Etc.), polyester decylamine, polyamidoximine, polypropylene decylamine, polyamino thioether, and the like. These may be used alone or in combination of two or more.

Among these, it is preferable that the resin contains at least one selected from the group consisting of structural units represented by the following formulas (1), (2), and (3) (hereinafter, it may be referred to as "first resin"). ).

Such a first resin is preferably a condensation resin such as urea resin, sulfur urea resin, bird manure amine resin, melamine resin, pulse resin, urea-melamine resin, urea-benzoguanamine resin, phenol-melamine resin, A combination of naphthol-melamine resin, alkoxyphenyl-melamine resin, alkoxynaphthalene-melamine resin, alkoxyquinone-melamine resin, benzoguanamine-melamine resin, aromatic polyamine-melamine resin, etc. An amine-based resin such as a condensation resin. Among these, phenol-melamine resin, naphthol-melamine resin, alkoxyphenyl-cyanide An amine resin, an alkoxynaphthalene-melamine resin, an alkoxyquinone-melamine resin, a melamine resin (melamine-formaldehyde resin), and the like.

The weight average molecular weight (Mw) of the first resin is particularly preferably from 1,000 to 8,000. If the above weight average molecular weight (Mw) is less than 1,000. When the photoresist underlayer film is formed, the low molecular component will volatilize from the photoresist underlayer film and contaminate the coating device. In addition, if it is 8000 or more, it is feared that the through-hole embedding property necessary for the double damascene structure process is lowered.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the first resin is preferably 7.0 or less. When the above Mw/Mn is 7.0 or more, the coating property is deteriorated.

The composition for a photoresist base film of the present embodiment has an advantage in that a resin containing a nitrogen atom has a high content of nitrogen atoms contained in one structural unit, and contains a resin (first resin). The resin of at least one of the groups consisting of the structural units represented by the above formulas (1), (2), and (3) can increase the amount of nitrogen atoms contained in the photoresist underlayer film.

The first resin can be produced by reacting a compound having a triazine structure with a compound having an aldehyde group. When the compound having a triazine structure is reacted with a compound having an aldehyde group, there is an advantage that the first resin can be easily obtained.

The compound having a triazine structure which can be used in the production of the first resin is not particularly limited as long as it has a triazine structure, and examples thereof include a compound represented by the following formula (5), and The compound represented by the formula (6) and the like. These compounds can be used singly or in combination of two or more.

(In the above formula (5), R ³ represents a carbon number of 1 to 6 amine groups, an alkyl group having 1 to 6 carbon atoms, a phenyl group, a hydroxyl group, a hydroxyalkyl group having 1 to 6 carbon atoms, and a carbon number of 1 to 8; An alkyl ether group, a carboxyl group having 1 to 12 carbon atoms, a carboxylic acid having 1 to 8 carbon atoms, a cyano group having 1 to 6 carbon atoms, or a halogen atom. Further, the R ³ groups may be the same or may be the same. Different).

(In the above formula (6), R ⁴ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, a hydroxyl group, a hydroxyalkyl group having 1 to 6 carbon atoms, or a carboxyl group having 1 to 12 carbon atoms. a carboxylic acid group having 1 to 8 carbon atoms, a cyano group having 1 to 6 carbon atoms, or a halogen atom. Further, the R ⁴ groups may be the same or different.

Examples of the compound represented by the formula (5) include a guanamine derivative such as melamine, acetaminophen or benzoguanamine, cyanuric acid, or methyl cyanurate. A cyanuric acid derivative such as ethyl cyanurate, etidinyl cyanurate or cyanuric chloride. Among these, it is preferred that two or three R ³ are an amine-based melamine or a guanosine amine or a guanoguanamine derivative such as benzoguanamine. Moreover, these can be used individually or in combination of 2 or more types.

The compound represented by the formula (6) may, for example, be a polyisocyanate, a methyl trimer isocyanate, an ethyl trimer isocyanate, an allyl trimer isocyanate, a 2-hydroxyethyltrimeric isocyanate or a 2-carboxyl group. a trimeric isocyanate derivative such as a trimeric isocyanate or a chlorinated isocyanuric acid. Among these, trimeric isocyanic acid in which all of R ⁴ is a hydrogen atom is preferable. Moreover, these can be used individually or in combination of 2 or more types.

The compound having an aldehyde group which can be used in the production of the first resin is not particularly limited as long as it has an aldehyde group, and examples thereof include formaldehyde, p-formaldehyde, trioxane, acetaldehyde, propionaldehyde, butyraldehyde, and the like. Trimethylacetaldehyde, acrolein, crotonaldehyde, cyclohexanal, furfural, furanyl acrolein, benzaldehyde, p-nonylaldehyde, phenylacetaldehyde, α-phenylpropanal, β-phenylpropanal, adjacent -hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, cinnamon Aldehyde, etc. Further, these may be used alone or in combination of two or more. In a compound having such an aldehyde group, easyness is obtained, The viewpoint of ease of handling is preferably formaldehyde. The formaldehyde system is not particularly limited, but formalin, paraformaldehyde, and the like can be suitably used.

The amount of the compound having a triazine structure and the compound having an aldehyde group which can be used in the production of the first resin is not particularly limited, but when a compound represented by the formula (5) is used as a compound having a triazine structure, The compound having the aldehyde group is preferably used in an amount of 10 to 200 parts by mass, more preferably 20 to 100 parts by mass, and particularly preferably 20 to 60 parts by mass, based on 100 parts by mass of the compound represented by the formula (5). By using the compound having an aldehyde group in the above range, the ruthenium can control the molecular weight.

Further, the first resin can be obtained, for example, by polymerizing a glycoluril derivative represented by the following formula (7).

(In the above formula (7), R ⁵ is independently a hydrogen atom, a methyl group, an ethyl group, a propyl group or a butyl group. Further, R ⁵ is the same or different.)

The reaction conditions for producing the first resin are not particularly limited, but the reaction temperature is preferably 50 to 200 ° C, more preferably 50 to 150 ° C, and particularly preferably 50 to 100 ° C. Moreover, it is particularly preferable to have a reaction time of 1 to 5 hours.

The resin containing a nitrogen atom contains at least one selected from the group consisting of structural units represented by the following formulas (1), (2), and (3), and more preferably contains the following formula (4). The resin of the structural unit shown (hereinafter, referred to as "second resin").

(In the above formula (4), R ¹ represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a hydroxyl group, a substituted hydroxyalkyl group having 1 to 6 carbon atoms, and a carbon number. 1 to 20 substitutable alkoxy group, 1 to 6 carbon atom-substituted alkylthio group, aralkylthio group or arylthio group, amine group, substituted alkyl group having 1 to 6 carbon atoms An amine group, an aralkylamino group or an arylamine group, a halogen atom, or a substitutable aryl group having 7 to 20 carbon atoms; x is an integer of 1 to 6, an integer of y is 0 to 2, and x is 2 or more. In time, the lines R ¹ may be the same or different, respectively.

In the composition for a photoresist base film of the present embodiment, the etching resistance can be further improved by the structural unit represented by the above formula (4) in the second resin.

In the above formula (4), R ¹ may, for example, be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group or a decyl group. An alkyl group such as undecyl, dodecyl, tridecyl, tetradecyl, or pentadecyl; hydroxy; hydroxymethyl, 2-hydroxyethyl, 3-hydroxy a hydroxyalkyl group such as a propyl group; a methoxy group, an ethoxy group, a propoxy group, an isopropyl group, a butoxy group, an isobutoxy group, a third butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group , octyloxy, decyloxy, nonyloxy, undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy, pentadecyloxy, pentadecyloxy, etc. An alkoxy group; an alkylthio group such as a hydrogenthio group, a methyl sulfide, an ethyl sulfide, a propyl sulfide, a butyl sulfide or a hexylsulfide; or an aromatic group having a substituent such as a benzyl sulfide or a phenylsulfide; An alkylthio group or an arylthio group;

Also may have an amine group, methylamine, ethylamine, propylamine, isopropylamine, butylamine, hexylamine, dimethylamine, methylethylamine, diethylamine, dipropylamine An amine group of an alkyl group such as dibutylamine; an aralkylamino group or an arylamine group such as a benzylamino group, a diphenylmethyl group or a tritylamino group; a fluorine, a chlorine, an iodine or the like; a halogen atom; the above-mentioned hydroxyl group, hydroxyalkyl group, alkoxy group, thiol group, alkylthio group, arylalkylthio group or arylthio group which may have a substituent, or an amine group of an alkyl group, a substituted group such as a phenyl group, an alkyl group or a phenyl group substituted with a halogen atom such as an aralkylamino group or an arylamine group; or an aryl group such as a phenyl group, a naphthyl group, an onion group or a methyl fluorenyl group.

Among these, it is preferably hydroxy, methoxy, ethoxy, propoxy or isopropyl. , butoxy, isobutoxy, tert-butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, decyloxy, undecyloxy, dodeca An alkoxy group such as an oxy group, a thirteenth carbonoxy group, a tetradecyloxy group, a pentadecyloxy group or a pentadecyloxy group; more preferably a methoxy group, an ethoxy group or a third butoxy group.

The reason for this is that when the second resin having an alkyl group, a hydroxyalkyl group or an aryl group is polymerized, it is compared with the other substituents (alkyl, hydroxyalkyl, and aryl groups) described above. When the polymerization conversion rate is low, the second resin having an alkylthio group, an aralkylthio group, an arylthio group or a halogen atom is compared with the other substituents described above (alkylthio group, aralkyl sulfide) a substituent other than a group, an arylthio group or a halogen atom), which is slightly inferior in etching resistance, and a second resin having an amine group, an aralkylamino group or an arylamine group is the other substituent described above (Substituents other than an amine group, an aralkylamino group, or an arylamine group) may react with an acid (PAG) contained in a photoresist film formed on the photoresist underlayer film.

In the above formula (4), x is an integer of 1 to 6, and a viewpoint of obtaining a second resin having a narrow molecular weight distribution is preferably 1 or 2, more preferably 2.

In the above formula (4), y is an integer of 0 to 2. That is, when the structural unit system y represented by the general formula (4) is “0”, it is derived from a phenyl derivative, when y is “1”, it is derived from a naphthalene derivative, and y is “2”. The time is derived from the 蒽 derivative.

Further, the resin containing a nitrogen atom is also contained in addition to the structural unit represented by the above formulas (1), (2), and (3) and the structural unit represented by the above formula (4). Other structural units that are co-aggregated by such building units. That is, the first resin is in addition to the above formula In addition to the structural units shown in (1), (2), and (3), there are also other structural units that can be copolymerized with the structural units, and the second resin is in addition to the above formula (1), ( In addition to the structural units shown in 2), (3), and (4), other structural units that can be copolymerized with the structural units are also included.

The second resin can be produced, for example, as follows. In other words, the method described in JP-A No. 8-311142 can be obtained by a coupling reaction of a compound having a phenyl derivative and a triazine structure with a compound having an aldehyde group. Further, it can also be obtained by reacting a phenyl derivative with a glycoluric acid represented by the above formula (7) under an acidic catalyst.

In addition, the resin containing the nitrogen atom contained in the composition for a photoresist base film of the present embodiment is not particularly limited as long as it can constitute a structural unit represented by the formula (4), and is substituted for the phenyl group. The derivative can be synthesized by using a naphthalene derivative or an onion derivative. Further, it is also possible to synthesize a compound containing at least one selected from the group consisting of a phenyl derivative, a naphthalene derivative, and an onion derivative.

The phenyl derivative is not particularly limited as long as it can constitute a structural unit represented by the formula (4), and examples thereof include phenol, cresol, dimethylphenol, ethylphenol, butylphenol, and anthracene. Alkyl phenols such as phenols and octyl phenols, polyphenols such as bisphenol A, bisphenol F, bisphenol S, resorcinol and catechol, halogenated phenols, phenylphenols, aminophenols Wait. Moreover, these can be used individually or in combination of 2 or more types.

The naphthyl derivative is not particularly limited as long as it can constitute a structural unit represented by the formula (4), and examples thereof include 1,3-dihydroxynaphthalene. 1,3-Dimethoxynaphthalene, 1,3-di-butoxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dimethoxynaphthalene, 2,3-di-t-butylnaphthalene , 2,4-dihydroxynaphthalene, 2,4-dimethoxynaphthalene, 2,4-di-t-butylnaphthalene, 2,5-dihydroxynaphthalene, 2,5-dimethoxynaphthalene, 2, 5-di-t-butylnaphthalene, 2,6-dihydroxynaphthalene, 2,6-dimethoxynaphthalene, 2,6-di-t-butoxynaphthalene, 2,7-dihydroxynaphthalene, 2,7 -dihydroxynaphthalene, 2,7-di-t-butylnaphthalene, 2,8-dihydroxynaphthalene, 2,8-dimethoxynaphthalene, 2,8-di-t-butoxynaphthalene, 2,2- Bis{4-(6-hydroxy-2-naphthalenyloxy)phenyl}propane, 2,2-bis{4-(6-hydroxy-2-naphthalenyloxy)phenyl}-1,3-hexafluoropropane Wait. Moreover, these can be used individually or in combination of 2 or more types.

The onion-based derivative is not particularly limited as long as it can constitute a structural unit represented by the formula (4), and examples thereof include 1-onion carboxy ether, 2-onion carboxylate, and 9-onion carboxylate. , 8-onion dicarboxylic acid dimethyl ester, 9,10-bis(3,5-dihydroxyphenyl) onion, 1,8-bis(hydroxymethyl) onion, 9,10-dibromo onion, 9, 10-dichloro onion, 9,10-dimethyl onion, 9,10-diphenyl onion, 9-(2-hydroxyethyl) onion, 2-(hydroxymethyl) onion, 9-(hydroxymethyl ) Onion, 9-methyl onion, 9-phenyl onion, 1,8,9-trihydroxy onion, and the like. Moreover, these can be used individually or in combination of 2 or more types.

When a resin containing a nitrogen atom is synthesized using at least one compound selected from the group consisting of a phenyl derivative, a naphthalene derivative, and an onion derivative, first, having at least one selected from the group consisting of a phenyl derivative and naphthalene is used. The compound of the group consisting of the substance and the onion derivative is mixed with the compound having an aldehyde group and the compound having a triazine structure at a temperature of 80 to 220 ° C for 1 to 12 hours and a pH of 4 to 10 (preferably pH 5 to 9). Reaction under conditions. In the above reaction, a catalyst may also be used, and in the case of a catalyst, an alkaline catalyst is preferably used. Examples of the basic catalyst include ammonia, 1-3 amines, and hexamethylenetetramine.

In the above reaction, the reaction sequence (subjecting order) of each raw material is not particularly limited. First, at least one selected from the group consisting of a phenyl derivative, a naphthalene derivative, and an onion derivative and a compound having an aldehyde group are provided. After the reaction, a compound having a triazine structure may be added to the reaction solution. Further, after reacting a compound having a triazine structure with a compound having an aldehyde group, at least one selected from the group consisting of a phenyl derivative, a naphthalene derivative, and an onion derivative may be added to the reaction liquid. Further, it is also possible to carry out the reaction by adding all the raw materials at the same time.

The molar ratio of the compound having an aldehyde group to the total amount of the phenyl derivative, the naphthalene derivative, and the onion derivative and the compound having the triazine structure "1" is preferably 0.2 to 0.9, more preferably It is 0.4~0.8.

The mass ratio of the total amount of the phenyl derivative, the naphthalene derivative, and the onion derivative to the compound having a triazine structure is preferably from 10 to 98:90 to 2, more preferably from 30 to 95:70 to 5. When the total amount of the phenyl derivative, the naphthalene derivative, and the onion derivative is less than 10, it may be difficult to synthesize the resin.

The above reaction can also be carried out in the presence of various reaction solvents from the viewpoint of controlling the reaction. The reaction solvent may, for example, be acetone, MEK (methyl ethyl ketone), toluene, xylene, methyl isobutyl ketone, ethyl oleate, ethylene glycol monomethyl ether, N, N-dimethylformamide, methanol. , ethanol, etc. These reaction solvents may be used alone or in combination of two or more.

Moreover, the reaction temperature in the above reaction is preferably 40 to 120 ° C, more preferably It is 50~100 °C. The reaction time is preferably from 1 to 48 hours, more preferably from 1 to 24 hours.

The resin containing a nitrogen atom is low in impurities such as a halogen or a metal, and the residual monomer or oligomer component is preferably a predetermined value or less. For example, the above residual monomer or oligomer measured by HPLC (High Speed Liquid Chromatography) is preferably 0.1% by mass. When the amount of residual monomers or oligomers is less than or equal to a predetermined value, the embedding property can be improved, the amount of sublimation substances during baking can be reduced, and the coating property and process safety can be further improved. A composition for a photoresist film having a small amount of change in the liquid in the liquid for a long period of time.

The method of purifying the resin containing a nitrogen atom may, for example, be the following method. The method for removing impurities such as metal may, for example, be a method of adsorbing a metal in a resin solution using a Zeta potential filter membrane, and washing the resin solution with an acidic aqueous solution such as alginic acid or sulfonic acid. A method in which a metal is formed in a twisted state and removed.

The method for removing residual monomer or oligomer component to a predetermined value or less is a liquid extraction method in which residual monomer or oligomer component is removed by washing with water or a suitable solvent; a method for purifying a solution state such as ultrafiltration in a molecular weight or lower; a resin solution is dropped into a weak solvent, a resin is solidified in a weak solvent to remove a residual monomer, and the reprecipitation method is removed; and the filtered resin is washed with a weak solvent. A method of purifying a solid state such as a slurry or the like.

The weight average molecular weight (Mw) of the second resin is preferably from 1,000 to 20,000, more preferably from 1,000 to 7,000, particularly preferably from 1,000 to 5,000. If the above weight average molecular weight (Mw) is less than 1000, when the photoresist underlayer film is formed At the time of the baking, the low molecular component will volatilize from the photoresist underlayer film, contaminating the coating device. In addition, if it is 20,000 or more, it is feared that the through-hole embedding property required for the dual damascene process is lowered.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the second resin is preferably 7 or less. When the above Mw/Mn is 7 or more, the coating property may be deteriorated.

The resin containing a nitrogen atom may be used singly or in combination of two or more.

[1-2 solvent]

The solvent which can be contained in the composition for a photoresist base film of the present embodiment is not particularly limited as long as it is a resin containing the above nitrogen atom, and examples thereof include ethylene glycol monomethyl ether and B. Ethylene glycol monoalkyl ethers such as diol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol single Ethylene glycol monoalkyl ether acetate such as ethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate; diethylene glycol dimethyl Diethylene glycol dialkyl ethers such as ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether; triethylene glycol dimethyl ether And triethylene glycol dialkyl ethers such as triethylene glycol diethyl ether;

Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, etc.; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl Propylene glycol dialkyl ethers such as propyl ether, propylene glycol di-n-butyl ether, propylene glycol methyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, and propylene glycol Propylene glycol monoalkyl ether acetate such as alcohol mono-n-butyl ether acetate; lactic acid methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, etc. Esters; methyl formate, ethyl formate, ethyl formate, n-propyl formic acid, isopropyl formate, n-butyl formate, isobutyl formate, n-amyl formate, isoamyl formate, methyl acetate, acetic acid Ethyl ester, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isopropyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, propionic acid Propyl ester, isopropyl propionate, n-butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, isobutyl butyrate, etc. Aliphatic carboxylic acid esters; ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropanoate, 2-hydroxy-3-methylbutyric acid Ester, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxy P-propyl acetate , 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3 Other esters such as methoxybutyl butyrate, methyl acetoxyacetate, methyl trimethyl propionate, and ethyl trimethyl propionate; 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, cyclohexanone, etc.; N-methylformamide, N , phthalamides such as N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone; lactones such as γ-butyrolactone Wait.

These solvents are appropriately selected. Preferred is propylene glycol monomethyl ether, Ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, γ - Butyrolactone and the like. These solvents may be used alone or in combination of two or more.

The amount of the solvent to be used is not particularly limited, but it is preferably used in such a manner that the solid content concentration of the obtained composition for a photoresist base film is 5 to 80% by mass, and more preferably 4 to 40% by mass. In particular, it is preferably used in an amount of 10 to 30% by mass. Further, the solid content concentration is preferably appropriately selected depending on the film thickness of the photoresist underlayer film to be formed.

The composition for a photoresist base film of the present embodiment may further contain various kinds of an acid generator, a crosslinking agent, a radiation absorber, a surfactant, a storage stabilizer, an antifoaming agent, and a bonding aid, etc., as needed. additive. Among these additives, it is preferred to contain at least one selected from the group consisting of an acid generator and a crosslinking agent.

[1-3] Acid generator

An acid generator is a component that produces an acid by exposure or heating. The acid generator prevents the generation of an acid in the photoresist undercoat film by the stimulation of light or heat, so that the acid (PAG) contained in the photoresist layer formed on the photoresist underlayer film is immersed in the photoresist underlayer. membrane. Therefore, a good photoresist pattern can be formed.

An acid generator (hereinafter sometimes referred to as an "acid generator") which generates an acid by exposure may, for example, be diphenyliodonium trifluoromethanesulfonate or diphenyliodonium nonafluorobutanesulfonate. Diphenyl iodonium sulfonate, diphenyl iodonium n-dodecyl benzene sulfonate, diphenyl iodonium 10 - camphor sulfonate, diphenyl Iodine iodide naphthalenesulfonate, diphenyliodonium hexafluoroantimonate, bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate, bis(4-tert-butylphenyl) Iodine 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 trifluoromethane Sulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10 - camphorsulfonate, triphenylsulfonium hexafluoroantimonate, 4-hydroxyphenyl ‧ phenyl ‧ methyl sulfonium p-toluene sulfonate, 4-hydroxyphenyl ‧ benzyl ‧ methyl thiopurine P-toluenesulfonate, cyclohexyl‧methyl‧2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldicyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethyl Pyrithione trifluoromethanesulfonate, 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4- Cyan-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldimethyl Thiol trifluoromethanesulfonate, 4-nitro-1-naphthyl diethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyl Diethylsulfonium trifluoromethanesulfonate, 1-(4-hydroxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-methoxynaphthalen-1-yl)tetra Hydrothienyl trifluoromethanesulfonate, 1-(4-ethoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-methoxy Methoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-ethoxymethoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1 -[4-(1-methoxyethoxy)naphthalen-1-yl]tetrahydrothiophene trifluoromethanesulfonate, 1-[4-(2-methoxyethoxy)naphthalene-1- Tetrahydrothiophene trifluoromethanesulfonate, 1-(4-methoxycarbonyloxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-ethoxycarbonyloxyl Naphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-n-propoxycarbonyloxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4- Isopropoxycarbonyloxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-n-butoxycarbonyloxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate , 1-(4-Tertioxycarbonyloxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-[4-(2-tetrahydrofurfuryloxy)naphthalen-1-yl Tetrahydrothiophene trifluoromethanesulfonate, 1-[4-(2-tetrahydropyranyloxy)naphthalen-1-yl]tetrahydrothiophene trifluoromethanesulfonate, 1-(4-benzene Methyloxy)tetrahydrothiophene trifluoromethanesulfonate, 1-(naphthylethylidenemethyl)tetrahydrothiophene trifluoromethanesulfonate, etc. Salt photoacid generators; phenyl bis(trichloromethyl)-s-triazine, 4-methoxyphenyl bis(trichloromethyl)-s-triazine, 1-naphthyl bis (three) Halogen-containing compounds such as chloromethyl)-s-triazine are photoacid generators; 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5 - 1,2-naphthoquinonediazide-4-sulfonate or 1,2-naphthoquinonediazide-5- of sulfonyl chloride, 2,3,4,4'-tetrahydroxybenzophenone A diazo ketone compound such as a sulfonate is a photoacid generator; an oxime compound such as 4-triphenylhydrazine methyl hydrazine, trimethylphenyl hydrazine methyl hydrazine or bis(phenylsulfonyl) methane is light. Acid generators; Benzene p-toluenesulfonate, benzenetriol tris(trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxy onion-2-sulfonate, trifluoromethanesulfonate Bicyclo[2,2,1]hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, 1,8-naphthalene dicarbonate A phthalic acid compound such as a trifluoromethanesulfonate is a photoacid generator or the like.

Among the above photoacid generators, diphenyl iodonium trifluoromethane sulfonate, diphenyl iodonium nonafluoro n-butane sulfonate, diphenyl iodonium sulfonate, diphenyl iodonium N-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate Acid ester, bis(4-t-butylphenyl)iodonium nonafluoro-n-butane sulfonate, bis(4-t-butylphenyl)iodonium n-dodecylbenzenesulfonate, double (4-Terbutylphenyl) iodonium 10-camphorsulfonate, bis(4-t-butylphenyl)iodonium naphthalenesulfonate. Further, the photoacid generator may be used singly or in combination of two or more.

Further, an acid generator (hereinafter sometimes referred to as "thermal acid generator") which generates an acid by heating may, for example, be 2,4,4,6-tetrabromocyclohexanedione or benzoin p-toluenesulfonate. , 2-nitrobenzyl p-toluenesulfonate, alkyl sulfonate, and the like. Moreover, these thermal acid generators can be used individually or in mixture of 2 or more types. Further, a photoacid generator and a thermal acid generator may be used in combination.

The amount of the acid generator to be used is preferably 5,000 parts by mass or less, more preferably 0.1 to 1000 parts by mass, even more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the resin containing a nitrogen atom.

[1-4] Crosslinker:

The crosslinking agent has a function of preventing the crack of the photoresist underlayer film in addition to preventing intermixing between the photoresist underlayer film and the photoresist film. Examples of such a crosslinking agent include polynuclear phenols and curing agents.

The polynuclear phenols may, for example, be 4,4'-biphenyl diol, 4,4'-methylene bisphenol, 4,4'-ethylene bisphenol, bisphenol A or the like; , 4',4"-methinetriol, 4,4'-[1-{4-(1-[4-hydroxyphenyl]-1-methylethyl)phenyl}ethylidene] double 3 phenols such as phenol; polyphenols such as novolacs, etc. Among these polynuclear phenols, 4,4'-[1-{4-(1-[4-hydroxyphenyl] can be suitably used. Further, the polynuclear phenols may be used singly or in combination of two or more kinds thereof in the form of -1-methylethyl)phenyl}ethylidene] bisphenol, novolac, polyhydroxystyrene, and the like.

The hardener may, for example, be 2,3-tolyl diisocyanate, 2,4-tolyl diisocyanate, 3,4-tolyl diisocyanate, 3,5-tolyl diisocyanate, 4,4'- Diisocyanates such as diphenylmethane diisocyanate, hexamethylene diisocyanate, and 1,4-cyclohexane diisocyanate.

Further, various types of commercially available persons can be used as the hardener. Specifically, the following trade names may be, for example, Epicote 812, Epicote 815, Epicote 826, Epicote 828, Epicote 834, Epicote 836, Epicote 871, Epicote 1001, Epicote 1004, Epicote 1007, Epicote 1009, Epicote 1031 (above, oiled shell) Epoxy Co., Ltd., Araldite 6600, Araldite 6700, Araldite 6800, Araldite 502, Araldite 6071, Araldite 6084, Araldite 6097, Araldite 6099 (above, Ciba Geigy), DER 331, DER 332, DER 333, DER 661, DER 644, DER 667 (to Epoxy compounds, etc., manufactured by Dow Chemical Co., Ltd.; Cymel 300, Cymel 301, Cymel 303, Cymel 350, Cymel 370, Cymel 771, Cymel 325, Cymel 327, Cymel 703, Cymel 712, Cymel 701, Cymel 272, Cymel 202, Mycoat 506, Mycoat 508 (above, Mitsui Cyanamid Co., Ltd.) and other melamine-based hardeners; Cymel 1123, Cymel 1123-10, Cymel 1128, Mycoat 102, Mycoat 105, Mycoat 106, Mycoat 130 (above, Mitsui Cyanamid Co., Ltd. A benzoguanamine-based hardener such as Cymel 1170, Cymel 1172 (above, Mitsui Cyanamid Co., Ltd.), Nikalac N-2702 (manufactured by Sanwa Chemical Co., Ltd.), or the like.

Among these hardening agents, a melamine-based curing agent, a glycoluril-based curing agent, and the like are preferable. These hardeners can be used individually or in mixture of 2 or more types. Further, a polynuclear phenol and a curing agent may be used in combination as a crosslinking agent.

The amount of the crosslinking agent used is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, based on 100 parts by mass of the resin containing a nitrogen atom.

Examples of the radiation absorbing agent include dyes such as oil-soluble dyes, disperse dyes, basic dyes, methylene-based dyes, pyrazole dyes, imidazole dyes, and hydroxy azo dyes; and Bicucine-derived dyes; , Norbicucine, stilbene, 4,4'-diamino stilbene derivative, coumarin derivative, pyrazoline derivative Fluorescent whitening agents such as hydroxy azo dyes, the brand name "Tinuvin 234" manufactured by Ciba Geigy Co., Ltd., and the UV absorbers such as the product name "Tinuvin 1130" manufactured by Ciba Geigy Co., Ltd.; onion derivatives, onions ketone An aromatic compound such as a derivative. Moreover, these radiation absorbers can be used individually or in mixture of 2 or more types.

The amount of the radiation absorber to be used is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of the resin containing a nitrogen atom.

The surfactant is a component which has an effect of improving coatability, streaking property, wettability, and development property. Such a surfactant may, for example, be polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-decyl phenyl ether, A nonionic surfactant such as polyethylene glycol dilaurate or polyethylene glycol distearate, or all of the following trade names, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, Polyflow No. 95 (above, Co., Ltd., Eftop EF101, Eftop EF204, Eftop EF303, Eftop EF352 (above, Tokem Products), Megafack F171, Megafack F172, Megafack F173 (above, Dainippon Ink Chemical Industry) Company system), Fluorad FC430, Fluorad FC431, Fluorad FC135, Fluorad FC93 (above, Sumitomo 3M), Asahiguard AG710, Sarflon S382, Sarflon SC101, Sarflon SC102, Sarflon SC103, Sarflon SC104, Sarflon SC105, Sarflon SC106 (above, Asahi Glass Co., Ltd.). Moreover, these surfactants can be used individually or in mixture of 2 or more types.

The amount of the surfactant to be used is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of the resin containing a nitrogen atom.

[2] Manufacturing method of composition for photoresist underlayer film:

The method for producing the composition for a photoresist base film of the present embodiment is not particularly limited. However, when the resin containing the nitrogen atom and the solvent described above are contained, for example, it can be produced as follows. First, the solvent is added to the resin containing the nitrogen atom (the content of the nitrogen atom is 10% by mass or more) and the additive, and the solid content concentration of the composition for the photoresist underlayer film is 5~ Adjusted in a 50% by mass manner. In this case, the amount of the resin used is adjusted so that the content of the nitrogen atom in the formed photoresist film is 10% by mass or more. Thereafter, it can be filtered by a filtration membrane having a pore diameter of about 0.1 μm to obtain a composition for a photoresist base film.

[3] A method for forming a dual damascene structure, which has the following steps:

The photo-resist pattern of the photoresist film is etched by using a photoresist film formed with a photoresist pattern as a mask on the photoresist underlayer film formed by the composition for the photoresist underlayer film. a step of printing on the underlayer film of the photoresist (first transfer step); using a photoresist underlayer film of the photoresist pattern transferred with the photoresist film as a mask, and a low dielectric disposed under the photoresist underlayer film a step of transferring a photoresist pattern of the photoresist underlayer film on the electrically insulating film (second transfer step); after transferring the photoresist pattern of the photoresist underlayer film on the low dielectric insulating film, by plasma ashing The step of removing the photoresist underlayer film (underlayer film removal step).

In the method for forming a dual damascene structure of the present embodiment, the composition of the photoresist base film is excellent in the photoresist pattern, and the double dielectric structure (double damascene structure) having low damage to the low dielectric insulating film can be formed. ).

[3-1] First transfer step:

The method for forming a dual damascene structure of the present embodiment is first disposed on a photoresist underlayer film formed of the composition for a photoresist underlayer film, and a photoresist film having a photoresist pattern is used as a mask. The photoresist pattern of the photoresist film is transferred to the photoresist underlayer film by etching.

The photoresist film is not particularly limited as long as it is formed on the photoresist underlayer film formed of the above-described composition for a photoresist underlayer film, and is preferably formed by a photoresist. The formation of the photoresist composition of the film. The photoresist composition may, for example, be a positive or negative chemically amplified photoresist composition containing a photoacid generator, a positive photoresist composition composed of an alkali soluble resin and a quinonediazide sensitizer, and a base. A negative photoresist composition composed of a soluble resin and a crosslinking agent. The method of disposing the above-mentioned photoresist film on the photoresist underlayer film is not particularly limited, and for example, it can be carried out by spin coating.

Specifically, the photoresist composition is applied onto the photoresist underlayer film by spin coating, and then prebaking is performed by volatilizing the solvent in the coating film. The prebaking temperature can be appropriately adjusted depending on the type of the photoresist composition to be used, etc., but it is preferably 30 to 200 ° C, more preferably 50 to 150 ° C.

The film thickness of the photoresist film is preferably from 100 to 20,000 nm, more preferably from 100 to 200 nm.

The photoresist film formed by the photoresist composition may be disposed on the photoresist underlayer film by the above-described spin coating method or the like, and may have a step of irradiating (exposure step), developing, or the like by irradiation of the radiation. Photolithography of the photoresist process to form a photoresist pattern.

The exposure step of the photoresist process is a step of irradiating the photoresist film with a mask (network line) designed by the drawing device. The radiation used in this exposure step may be appropriately selected from visible light, violet light, far ultraviolet light, X-ray, electron beam, γ-ray, molecular line, ion beam, etc. depending on the kind of photoacid generator contained in the photoresist film. select. It is preferably a far ultraviolet ray, in particular, a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F ₂ excimer laser (wavelength 157 nm), a Kr ₂ excimer laser (wavelength 147 nm), ArKr excimer laser (wavelength 134 nm), extreme ultraviolet light (wavelength 13 nm), and the like.

The developing solution used for the development of the above-mentioned photoresist process may be appropriately selected depending on the type of the photoresist composition, but is composed of a positive type chemically amplified photoresist composition or a positive type resist containing an alkali-soluble resin. The developing solution used for the object may, for example, be sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine or triethylamine. Amine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, hexahydropyridine, choline, 1,8-diazobicyclo[5.4. An aqueous alkaline solution of 0]-7-undecene and 1,5-diazobicyclo[4.3.0]-5-decene. Further, in such an alkaline aqueous solution, an aqueous organic solvent such as an alcohol such as methanol or ethanol or a surfactant may be added in an appropriate amount.

The film thickness of the photoresist underlayer film is not particularly limited, but is preferably 100 to 2000 nm, more preferably 200 to 1000 nm, and particularly preferably 200 to 500 nm. When the film thickness of the photoresist underlayer film is less than 100 nm, the thickness of the mask when the substrate is processed is insufficient, and the substrate may not be processed. In addition, if it is 2000nm or more, it is The longitudinal/horizontal ratio (aspect ratio) of the patterned photoresist film (the pattern portion of the photoresist film forming the photoresist pattern) to be described later may be too large, and the patterned photoresist film may be patterned. Will dump.

Then, using the above-mentioned photoresist film as a mask, the photoresist pattern of the photoresist film is transferred to the photoresist underlayer film by etching. The etching system is not particularly limited, and may be any of dry etching or wet etching, and can be carried out by a conventionally known method. For example, in the dry etching, a gas source such as O ₂ , CO, CO ₂ or the like can be used. A gas containing an oxygen atom, an inert gas such as He, N ₂ or Ar, a chlorine-based gas such as Cl ₂ or BCl ₂ , or other H ₂ or NH ₂ . Further, these gases may be mixed and used.

[3-2] Second transfer step:

Then, in the method of forming the dual damascene structure of the present embodiment, the resistive underlayer film of the photoresist pattern transferred with the photoresist film is used as a mask by the first transfer step, and the photoresist underlayer film is used. The photoresist pattern of the photoresist underlayer film transferred on the low dielectric insulating film is disposed below.

The low dielectric insulating film (Low-k film) is not particularly limited as long as it can be disposed under the photoresist underlayer film, and examples thereof include cerium oxide, cerium nitride, and cerium oxynitride. An insulating film formed of polysiloxane or the like. Specifically, the following may be used, and all of them are trade names, and are formed by black diamond (manufactured by AMAT Co., Ltd.), Silk (manufactured by Dow Chemical Co., Ltd.), and LKD 5109 (manufactured by JSR Co., Ltd.).

The low dielectric insulating film is, for example, a film formed by coating a substrate such as a wafer, and the method for forming the film is not particularly limited, and can be carried out according to a known method. To implement. For example, it can be formed by a coating method (SOD: Spin On Dielectric) or a chemical vapor deposition (CVD: Chemical Vapor Deposition). In the method of forming the dual damascene structure of the present embodiment, the photoresist underlayer film is disposed on the low dielectric insulating film formed as described above. The method of disposing the photoresist underlayer film is not particularly limited, and for example, a method of forming a photoresist underlayer film on a low dielectric insulating film by a spin coating method using the above-described composition for a photoresist underlayer film can be mentioned.

Then, the photoresist pattern formed on the photoresist underlayer film is transferred onto the low dielectric insulating film. The method of transferring the photoresist pattern is not particularly limited and can be carried out by etching as described above.

[3-3] Base film removal step:

Then, in the method for forming the dual damascene structure of the embodiment, the photoresist pattern of the photoresist underlayer film is transferred onto the low dielectric insulating film by the second transfer step, and the light is removed by plasma ashing. Block the underlying film.

In the method for forming a dual damascene structure according to the present embodiment, the photoresist underlayer film contains 10% by mass or more of nitrogen atoms, so that when it is removed by plasma ashing, it is compared with the Daxi parameter from the photoresist underlayer film. The expected processing speed of ashing can be quickly removed. Therefore, it is possible to suppress damage caused by plasma ashing of the low dielectric insulating film disposed under the photoresist underlayer film.

Here, the plasma ashing is performed by a plasma of a reactive gas after the dry etching process, and a mask made of an organic substance (for example, a photoresist base film or a photoresist film) is removed, for example, a reaction gas such as an oxygen plasma is generated. The plasma is decomposed and removed into CO _x or H ₂ O in the gas phase.

The condition of the plasma ashing is not particularly limited as long as it is a photoresist-removable underlayer film, but the high-frequency power to be applied to the susceptor is 100 to 1000 W, more preferably 100 to 500 W, and the carrier temperature. It should be 20~100°C, more preferably 20~60°C. The pressure in the treatment vessel is preferably from 0.133 to 39.9 Pa, more preferably from 3.99 to 13.3 Pa.

The gas used for the plasma ashing is not particularly limited as long as it is a photoresist-removable underlayer film, but it is preferably from the viewpoint of suppressing an increase in the specific dielectric constant of the low dielectric insulating film caused by ashing. It contains at least one selected from the group consisting of nitrogen, hydrogen, ammonia, and hydrogen. Further, when a mixed gas of nitrogen and hydrogen is used, the capacity ratio is preferably 0 to 20, and more preferably 1 to 10, with respect to nitrogen 100. Further, when a mixed gas of ammonia and argon is used, the capacity ratio is preferably 0 to 10 with respect to nitrogen 100. By such a plasma of the mixed gas, the photoresist underlayer film can be removed more efficiently. Further, it is also preferably a mixed gas of ammonia, nitrogen and hydrogen.

[3-4] Other steps:

After the exposed photoresist film is developed, the photoresist film is preferably washed and dried. Further, in order to improve the resolution, the pattern outline, the developing property, and the like, post-baking may be performed after exposure and before development.

Further, an intermediate layer may be formed between the photoresist film and the photoresist underlayer film. The intermediate layer is a layer having a photoresist underlayer film, a photoresist film, and a function of both of them in the formation of a photoresist pattern. For example, when the anti-reflection function of the photoresist underlayer film is insufficient, it can be applied to a layer having an anti-reflection function in the intermediate layer. The material of the intermediate layer is suitable for selecting an organic compound or inorganic according to the desired function. Oxide. For example, when the photoresist film is an organic compound, an inorganic oxide may be applied to the intermediate layer.

The layer composed of the organic compound is commercially available, for example, all of which are trade names, "DUV-42", "DUV-44", "ARC-28", "ARC-29" manufactured by Brewer Science, etc. It is formed by "AR-3" and "AR-19" manufactured by Rohm & Hass Co., Ltd. for the trade name. Further, the intermediate layer composed of the inorganic oxide may be made of polysiloxane, titanium oxide, aluminum oxide or molybdenum oxide, and commercially available products such as "NFC SOG01" manufactured by JSR Corporation, for example, may be used. "NFC SOG04" or the like is formed by a CVD method.

As a method of forming the intermediate layer, a coating method, a CVD method, or the like can be used, but a coating method is preferred. In the case of the coating method, after the photoresist underlayer film is formed, the intermediate layer can be formed continuously, but the CVD method cannot be formed continuously.

The film thickness of the intermediate layer can be appropriately selected depending on the function of the intermediate layer, but it is preferably 10 to 3000 nm, more preferably 20 to 300 nm. If the film thickness of the intermediate layer is less than 10 nm, the intermediate layer may be scraped off during the etching of the photoresist underlayer film. On the other hand, when it is 3000 nm or more, when the photoresist pattern of the photoresist film is transferred to the intermediate layer, the difference in processing conversion is remarkably generated.

More specifically, one embodiment of the method for forming a dual damascene structure of the present invention will be described.

1 is a first low dielectric insulating film 2 formed on a substrate 1, and a photoresist pattern for transferring a photoresist film by dry etching on the photoresist underlayer film 3 formed on the first low dielectric insulating film 2 Type of example.

The method for forming the dual damascene structure of the present embodiment is based on the use of the above In the photoresist underlayer film formed of the composition for a photoresist base film of the present embodiment, the etching resistance is good, and the photoresist pattern can be favorably transferred to the photoresist underlayer film 3.

After the resist pattern is transferred to the photoresist underlayer film, a photoresist pattern (groove) is formed on the first low dielectric insulating film 2 by using the photoresist underlayer film 3 as a mask as shown in FIG. The formation of the photoresist pattern of the low dielectric insulating film is performed by reactive ion etching to remove the low dielectric insulating film corresponding to the portion of the photoresist pattern. FIG. 3 shows an example in which the photoresist underlayer film 3 is removed by plasma ashing after the dielectric insulating film 2 is formed into a photoresist pattern.

Further, a barrier metal film can be formed on the low dielectric insulating film as needed. 4 is an example in which a trench (wiring trench) 4 is formed and a barrier metal 5 is deposited on the surface of the first low dielectric insulating film 2 on which the wiring trench 4 is formed. When a barrier metal (barrier metal film) is formed, in addition to improving the adhesion of copper buried in the wiring trench and the low dielectric insulating film, copper can be prevented from diffusing into the low dielectric insulating film (migration).

Thereafter, copper is buried in the wiring trench by copper electrolytic plating or the like to form a lower copper wiring layer. Further, the low dielectric insulating film forming the photoresist pattern is not limited to one layer, and may be a plurality of layers in which a plurality of low dielectric insulating films are laminated. 5 is a buried copper layer by copper electrolytic plating or the like in the wiring trench 4, and the underlying copper wiring layer 6 can be formed, and the copper and the barrier metal 5 adhering to the surface of the first low dielectric insulating film 2 are removed by chemical polishing (CMP). After the surface of the first low dielectric insulating film 2 is planarized, a second low dielectric insulating film 7 and a first etch stop film are sequentially formed on the first low dielectric insulating film 2 in a lamination manner. 8. The third low dielectric insulating film 9 and the second etch stop film 10 are at the most The etching of the upper layer prevents the photoresist underlayer film 11 on the film 10 from forming a photoresist pattern.

Thereafter, as shown in FIG. 6, the resistive underlayer film 11 is used as a mask, and the second etching stopper film 10, the third low dielectric insulating film 9, and the first etching stopper layer 8 are penetrated by reactive ion etching. The second low dielectric insulating film 7 forms a through hole (resist pattern) 12 which reaches the surface of the underlying wiring layer 6, and thereafter, is subjected to plasma ashing treatment to remove the photoresist underlayer film.

After the photoresist ashing treatment is performed to remove the photoresist underlayer film, as shown in FIG. 7, the via hole 12 is filled, and the composition for the photoresist underlayer film is filled, and the second etching stopper film 10 is covered (the most of the laminates) The composition for the photoresist underlayer film is applied in the manner of the upper layer, and a photoresist pattern is formed on the photoresist underlayer film 13.

After the photoresist pattern is formed on the photoresist underlayer film 13, as shown in FIG. 8, the second etching stopper film 10 is etched by reactive ion etching using the photoresist pattern of the photoresist underlayer film 13 as a mask. A trench (resist pattern type) 14 is formed with the third low dielectric insulating film 9.

After the trench (photoresist pattern) 14 is formed, the photoresist underlayer film 13 is removed by plasma ashing. FIG. 9 is a double damascene structure having a through hole 12 and a trench 14 formed by ashing a photoresist base film buried in the through hole 12 and completely removing the photoresist base film disposed on the etching stopper film 10. example.

As described above, after the double damascene structure is formed, as shown in FIG. 10, the barrier metal 15 is formed in the through hole 12 and the trench 14, and copper is buried to perform CMP, and the via wiring 16 and the upper copper wiring layer are simultaneously formed. 17.

Further, the dual damascene structure is not limited to being formed by the above-described first through holes, but may be formed by first grooves. Moreover, by repeating the above process in sequence, it can be shaped A variety of multilayer wiring construction.

[Examples]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the examples. In addition, "parts" and "%" in the examples and comparative examples are based on quality unless otherwise stated.

(Reference example 1) [Adjustment of photoresist composition solution]

The loading tube with a separation of the flask at reflux, under a nitrogen flow, the feeding methyl-8-tert-butoxycarbonyl group methoxycarbonyl tetracyclo [4.4.0.1 ^2,5, 1 ^7,10] ten two 3-ene 29 parts, 8-hydroxy-8-methyl-tetracyclo [4.4.0.1 ^2,5, 1 ^7,10] dodeca-3-ene 10 parts, 18 parts of maleic anhydride, 2, 4 parts of 5-dimethyl-2,5-hexanediol diacrylate, 1 part of tert-dodecyl mercaptan, 4 parts of azobisisobutyrine and 1,2-diethoxy B 60 parts of alkane was used as a monomer component, and polymerization was carried out at 70 ° C for 6 hours while stirring to obtain a polymer containing the following repeating units (a), (b) and (c) (hereinafter, referred to as "resistance" The reaction solution of the polymer "). Thereafter, the reaction solution was poured into a mixed solvent of a large amount of n-hexane/isopropyl alcohol (mass ratio = 1/1) to solidify the photoresist in the reaction solution. The solidified photoresist is washed several times with the above mixed solvent. Thereafter, it was dried under vacuum to obtain a photoresist polymer (yield 60%). Further, the photoresist units of the repeating units (a), (b), and (c) had a molar ratio of 64:18:18 and a Mw of 27,000.

80 parts of the obtained photoresist polymer, 1.5 parts of 1-(4-methoxynaphthalen-1-yl)tetrahydrothiophene nonafluoro-n-butane sulfonate and 0.04 parts of tri-n-octylamine were dissolved in The mixed solution obtained in 533 parts of propylene glycol monomethyl ether acetate was used as a photoresist composition solution.

[Measurement of molecular weight]

The weight average molecular weight (Mw) of the photoresist polymer obtained in the above Reference Example 1 and the weight average molecular weight (Mw) of the resins (A-1) to (A-7) obtained in the following respective Synthesis Examples and The number average molecular weight (Mn) is a GPC column (G2000HXL: 2, G3000HXL: 1) manufactured by Tosoh Corporation, and the flow rate is 1.0 ml/min, the solvent of dissolution: tetrahydrofuran, and the column temperature: 40 ° C. The measurement was carried out by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard.

[Measurement of the content of nitrogen atoms in the resin]:

The content (% by mass) of the nitrogen atom of the resins (A-1) to (A-7) obtained in each of the following synthesis examples is an organic element analyzer manufactured by J-Science Co., Ltd. (trade name "CHN coater" JM10") and measured.

(Synthesis Example 1) [Synthesis of Resin (A-1)]:

To 100 parts of the phenol, 30 parts of 40% formalin and 0.47 parts of triethylamine were added, and the mixture was reacted at 80 ° C for 3 hours. Then, 30 parts of melamine was added, and the reaction was further carried out for 2 hours. After the reaction, the water was removed under normal pressure, and the temperature was raised to 180 ° C for 2 hours. Then, the unreacted phenol was removed under reduced pressure to obtain a resin (A-1) containing a nitrogen atom. (The following may be referred to as "resin (A-1)"). This resin (A-1) has a Mw of 4500. Mw/Mn was 1.80, and the content of nitrogen atoms was 10% by mass.

(Synthesis Example 2) [Synthesis of Resin (A-2)]

A yellow-white powder was obtained in the same manner as in Synthesis Example 1 except that 50 parts of melamine was used. A resin (A-2) containing a nitrogen atom (hereinafter sometimes referred to as "resin (A-2)") is obtained. The resin (A-2) had a Mw of 4,100, a Mw/Mn of 2.10, and a nitrogen atom content of 14% by mass.

(Synthesis Example 3) [Synthesis of Resin (A-3)]

A yellow-white powder was obtained in the same manner as in Synthesis Example 1 except that 70 parts of melamine was used. A resin (A-3) containing a nitrogen atom (hereinafter sometimes referred to as "resin (A-3)") is obtained. The resin (A-3) had a Mw of 3,900, a Mw/Mn of 2.20, and a nitrogen atom content of 21% by mass.

(Synthesis Example 4) [Synthesis of Resin (A-4)]:

To 100 parts of 1-naphthol, 30 parts of 40% formalin and 0.47 parts of triethylamine were added, and the mixture was reacted at 80 ° C for 3 hours. Then, 40 parts of melamine was added and further reacted for 2 hours. After the reaction, the water was removed under normal pressure, and the temperature was raised to 180 ° C for 2 hours. Then, unreacted 1-naphthol was removed under reduced pressure to obtain a resin (A-4) containing a nitrogen atom. (The following may be referred to as "resin (A-4)"). The resin (A-4) had a Mw of 5,100, a Mw/Mn of 2.20, and a nitrogen atom content of 15% by mass.

(Synthesis Example 5) [Synthesis of Resin (A-5)]

A yellow-white powder was obtained in the same manner as in Synthesis Example 4 except that 70 parts of melamine was used. A resin (A-5) containing a nitrogen atom (hereinafter sometimes referred to as "resin (A-5)") is obtained. This resin (A-5) has a Mw of 3900 and Mw/Mn is 2.30, the content of the nitrogen atom was 19% by mass.

(Synthesis Example 6) [Synthesis of Resin (A-6)]:

To 100 parts of 1,8-hydroxyindole, 30 parts of 40% formalin and 0.47 parts of triethylamine were added, and the mixture was reacted at 80 ° C for 3 hours. Then, 60 parts of benzoguanamine was added and further reacted for 2 hours. After the reaction, the water was removed under normal pressure, and the temperature was raised to 180 ° C for 2 hours. Then, the unreacted 1,8-hydroxyindole is removed under reduced pressure to obtain a resin (A-6) containing a nitrogen atom (hereinafter sometimes referred to as "resin (A-6)"). The resin (A-6) had a Mw of 5,200, Mw/Mn of 3.30, and a nitrogen atom content of 18% by mass.

(Synthesis Example 7) [Synthesis of Resin (A-7)]:

100 parts of 1-naphthol, 200 parts of tetramethoxymethyl glycoluril, and 3 parts of oxalic acid were dissolved in 900 parts of methyl isobutyl ketone, and then reacted at 80 ° C for 5 hours. After the reaction, water was added to the reaction mixture, and the mixture was washed until the aqueous layer became neutral. Then, the unreacted 1-naphthol and the solvent are removed under reduced pressure to obtain a resin (A-7) containing a nitrogen atom (hereinafter sometimes referred to as "resin (A-7)"). This resin (A-7) had Mw of 1300, Mw/Mn of 1.50, and a nitrogen atom content of 16 mass%.

(Example 1) [Modulation of composition for photoresist underlayer film]

10 parts of the above resin (A-1) and bis(4-t-butylphenyl)iodonium nonafluorotri-n-butanesulfonate as an acid generator (indicated as "C-1" in Table 2) 0.5 parts and tetramethoxymethyl glycoluril as a crosslinking agent (shown by the following formula (8). Table 2 shows "D-1") 0.5 part of propylene glycol monomethyl acetic acid dissolved in a solvent 89 parts of the ester (indicated as "B-1" in Table 2) was obtained to obtain a mixed solution. Thereafter, the mixed solution was filtered through a filtration membrane having a pore size of 0.1 μm to obtain a composition for a photoresist base film. The composition for the photoresist underlayer film was used as a coating liquid, and was used in various evaluations shown below.

[Determination of the content of nitrogen atoms in the photoresist underlayer film]:

First, a composition for a photoresist underlayer film was spin-coated on a wafer having a diameter of 8 inches. After spin coating, it was heated at 180 ° C for 60 seconds, and then heated at 250 ° C for 60 seconds on a hot plate to obtain a photoresist bottom layer having a film thickness of 300 nm. membrane. The content (% by mass) of each atom of carbon, hydrogen, oxygen, and nitrogen was measured for the obtained photoresist base film. For the measurement of the respective content ratio, an organic element analyzer (trade name "CHN coater JM10") manufactured by J-Science Co., Ltd. was used. In addition, in Table 4, "nitrogen content rate" indicates this evaluation.

[Daxi parameter]:

As a result of measuring the content of nitrogen atoms in the photoresist underlayer film, the Western parameters of the photoresist underlayer film were calculated from the content ratio of each element in the photoresist underlayer film by the following formula (i).

(i): NT/{NC-NO-(2×NX)} (However, in the above formula (i), NT is the total number of atoms, NC is the number of carbon atoms, NO is the number of oxygen atoms, and NX is the number of halogen atoms. )

[buried in Yutong Kong]

The composition for the photoresist base film obtained was satisfactorily immersed in the through-hole, and the embedding property of the via hole was evaluated as to whether or not it was buried well. The evaluation of the embedding property in the through hole was carried out by the following method.

First, a composition for a photoresist base film was spin-coated on a substrate of tetraethyl orthophthalate (TEOS) which was processed into a through-hole having a hole size of 140 nm, a hole pitch of 1 H/1.2 S, and a depth of 1000 nm. After spin coating, it is heated at 180 ° C for 60 seconds, and then further added to the hot plate at 250 ° C. Hot 60 seconds. In this manner, a photoresist base film having a film thickness of 300 nm was formed on the surface of the TEOS in the through hole. The produced underlayer film of the photoresist was evaluated by observing the buried state in the through hole by a scanning electron microscope. When the evaluation standard is that the photoresist underlayer film is formed in the through hole (in the case of being buried), it is good ("○"), and it is not good when it is buried ("X"). In addition, in Table 4, "buriedness" means this evaluation.

[Shape shape after development]:

First, a composition for a photoresist underlayer film was spin-coated on a wafer having a diameter of 8 inches. After spin coating, the film was heated at 180 ° C for 60 seconds, and then heated on a hot plate at 250 ° C for 60 seconds to obtain a photoresist underlayer film having a film thickness of 300 nm. Thereafter, a three-layer intermediate layer composition solution for a photoresist process (trade name: NFC SOG050, manufactured by JSR Corporation) was spin-coated on the photoresist underlayer film. After spin coating, it was heated at 200 ° C for 60 seconds, and then further heated at 250 ° C for 60 seconds on a hot plate to form an intermediate layer film having a film thickness of 50 nm. Thereafter, the photoresist composition solution obtained in Reference Example 1 was spin-coated on the intermediate layer film, and prebaked on a hot plate at 130 ° C for 90 seconds to form a photoresist film having a film thickness of 200 nm. Then, for this photoresist film, an ArF excimer laser exposure apparatus (number of lens openings of 0.78, exposure wavelength of 193 nm) manufactured by NIKON Co., Ltd. was used, and only the optimum exposure time was exposed through the mask pattern. Thereafter, after prebaking on a hot plate at 130 ° C for 90 seconds, the solution was developed at 25 ° C for 1 minute using a 2.38 mass % aqueous solution of tetramethylammonium hydroxide, washed with water, and dried to form on the above resist film. Positive photoresist pattern.

To evaluate the photoresist bottom layer formed as a composition for the photoresist underlayer film The function of the antireflection film of the film was evaluated by scanning electron microscope observation to evaluate the pattern shape of the positive resist pattern of the above resist film. When the evaluation reference pattern is a rectangle, it is good "(○)", and when it is not a rectangle, it is bad ("×"). In addition, in Table 4, "resistance shape" shows this evaluation.

[Anti-resident wave effect]:

In order to evaluate the function of the antireflection film as the underlayer film of the photoresist formed by the composition for the photoresist underlayer film, the presence or absence of the influence of the standing wave of the above-mentioned positive resist pattern was evaluated by scanning electron microscope observation. The evaluation criteria are good "(○)" when there is no standing wave, and sometimes it is bad ("×"). In addition, in Table 4, "anti-resident wave effect" means this evaluation.

[etching resistance]:

The pattern transfer performance and etching resistance of the photoresist underlayer film formed of the composition for the photoresist underlayer film were evaluated by the following methods. First, a photoresist base film having a film thickness of 300 nm was formed by spin coating. Thereafter, the photoresist underlayer film (pressure: 0.03 Torr, high frequency power: 3000 W, Ar/CF ₄ = 40/100 sccm, substrate temperature: 20 ° C) was etched, and the film thickness of the photoresist underlayer film was measured. . The etching rate (nm/min) was calculated from the relationship between the amount of decrease in film thickness and the treatment time.

[NH ₃ stripping]:

The peeling property of the photoresist underlayer film using plasma ashing of NH ₃ gas was carried out according to the following evaluation method. First, a photoresist film having a film thickness of 300 nm was formed by spin coating. Thereafter, plasma ashing treatment (pressure: 0.1 Torr, high frequency power: 550 W, NH ₃ = 150 sccm, substrate temperature: 20 ° C) was performed, and the film thickness of the photoresist underlayer film after the plasma ashing treatment was measured. The etching rate (nm/min) was calculated from the relationship between the amount of decrease in film thickness and the treatment time. Further, [NH ₃ peelability] in Table 4 indicates this evaluation.

[O ₂ stripping]:

The peeling property of the photoresist underlayer film using plasma ashing of O ₂ gas was carried out according to the following evaluation method. First, a photoresist base film having a film thickness of 300 nm was formed by spin coating. Thereafter, plasma ashing treatment (pressure: 0.1 Torr, high-frequency power: 550 W, O ₂ = 150 sccm, substrate temperature: 20 ° C) was performed, and the film thickness of the photoresist underlayer film after the plasma ashing treatment was measured. The etching rate (nm/min) was calculated from the relationship between the amount of decrease in film thickness and the treatment time. Further, [O ₂ peelability] in Table 4 indicates this evaluation.

The photoresist underlayer film formed by the composition for a photoresist base film of the present embodiment has a nitrogen content of 10% by mass, a large West parameter of 2.7, and a buried property of "○" in a via hole, and a pattern after development. The shape is "○", the anti-standing wave effect is "○", the etching resistance is 67 nm/min, the etching rate in the NH ₃ peeling property is 311 nm/min, and the etching rate in the O ₂ peeling property is 899 nm. /Minute.

(Examples 2 to 24)

The composition for the photoresist underlayer film was prepared in the same manner as in Example 1 except that the formulation was as shown in Table 2. Also, in Table 2, "A- 8" indicates the trade name "Sanol LS-944" manufactured by Sankyo Lifetech.

(Comparative examples 1 to 3)

The composition for the photoresist underlayer film was prepared in the same manner as in Example 1 except that the formulation was as shown in Table 3. In addition, "R-1" in Table 3 indicates polydecene (manufactured by JSR Corporation), and "R-2" indicates polyhydroxystyrene (trade name: Maruka Lyncur, manufactured by Nine-Chen Petrochemical Co., Ltd.), and "R- 3" represents polymethylpropionic acid (manufactured by JSR Corporation). In Table 3, R-1 to R-3 are represented by a polymer.

(Comparative examples 4 and 5)

The above various evaluations were carried out using a commercially available composition for a photoresist base film. In addition, in Table 3, "NFC1400" indicates the product name "NFC1400" manufactured by JSR Corporation, and "NFC1500" indicates the product name "NFC1500" manufactured by JSR Corporation.

The composition for each of the photoresist base film of Examples 2 to 24 and the composition for the photoresist base film of Comparative Examples 1 to 5 were subjected to the above evaluations. The results of the assessment are shown in 4, 5.

As shown in Tables 4 and 5, the photoresist underlayer film formed of the composition for a photoresist base film of Examples 1 to 24 has a content of nitrogen atoms in the photoresist underlayer film of 10% by mass or more. Therefore, it was confirmed that the photoresist base film formed by the composition for the photoresist base film of Comparative Examples 1 to 5 had good peelability with plasma ashing. Further, the photoresist base film formed of the composition for the photoresist base film of Examples 1 to 24 can be confirmed by the embedding property of the via hole, the pattern shape after development, and the evaluation of the anti-staging effect. Medium is a good result.

The etch resistance indicates the evaluation result of the trend of the Daxi parameters, but it can be confirmed that the NH ₃ peelability and the O ₂ peeling etch rate are superior to the Daxi parameters. For this reason, when the photoresist underlayer film is formed of the composition for the photoresist base film of Examples 1 to 24, it is estimated that it is related to the amount of nitrogen atoms contained in the photoresist underlayer film. Therefore, the photoresist underlayer film system having a large nitrogen atom content can be confirmed to have a good relative etching rate.

Further, the photoresist underlayer film formed of the composition for a photoresist base film of Comparative Examples 1 to 5 is the same as the photoresist underlayer film formed of the composition for a photoresist base film of Examples 1 to 24, Its etch resistance is in accordance with the trend of the Daxi parameters. Further, the NH ₃ peelability and the O ₂ peelability are also etch rates according to the trend of the Daxi parameter. Therefore, the content of the nitrogen atom of the photoresist base film formed by the composition for the photoresist base film of Comparative Examples 1 to 5 is less than 10% by mass, so that it is used for the photoresist base film of Examples 1 to 24. The photoresist underlayer film formed of the composition was found to have poor peelability due to plasma ashing (hard to be peeled off).

[Industry use possibility]

The composition for a photoresist base film of the present invention is well embedded in the through hole, has good etching resistance, is easily peeled off by plasma ashing, and can form pattern transfer performance (pattern shape after development, anti-reflection) The effect is excellent in the photoresist film. That is, since it is easily peeled off by plasma ashing, it is difficult to damage the low dielectric insulating film (it is difficult to increase the effective dielectric constant of the low dielectric insulating film), and the etching resistance is good and the antireflection effect is high. Since the pattern shape after development is good, it can be suitably used in the formation of a double damascene structure in a high-integrated circuit.

1‧‧‧Substrate

2‧‧‧First low dielectric insulating film

3,13‧‧‧Photoresist film

4‧‧‧ wiring trench (groove)

5,15‧‧‧Barrier metal

6‧‧‧Bottom copper wiring layer

7‧‧‧Second low dielectric insulating film

8‧‧‧First etch stop layer

9‧‧‧ Third low dielectric insulating film

10‧‧‧Second etch stop layer

11‧‧‧Photoresist film

12‧‧‧through holes

14‧‧‧ trench

16‧‧‧through hole wiring

17‧‧‧Upper copper wiring layer

Fig. 1 is a schematic view showing a step of a method of forming a dual damascene structure of the embodiment.

Fig. 2 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 3 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 4 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 5 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 6 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 7 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 8 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 9 is a schematic view showing a step of a method of forming the dual damascene structure of the embodiment.

Fig. 10 is a cross-sectional view showing a state in which a double damascene structure formed by the method for forming a dual damascene structure of the present embodiment is wired.

Claims (7)

A composition for a photoresist underlayer film which is coated on a substrate and dried by heating at 250 ° C for 60 seconds to form a photoresist substrate having a thickness of 300 nm, and the content of nitrogen atoms in the photoresist underlayer film formed is formed. The content is 10% by mass or more, and is characterized by comprising a resin containing a nitrogen atom and a solvent, and the resin contains 10 to 20% by mass of the nitrogen atom. The composition for a photoresist base film according to the first aspect of the invention, wherein the resin contains at least one selected from the group consisting of structural units represented by the following formulas (1), (2), and (3). The composition for a photoresist base film according to the second aspect of the invention, wherein the ratio of the total of the structural units represented by the formulas (1), (2) and (3) contained in the resin is 10 to 50 mass. %. The composition for a photoresist base film according to the second or third aspect of the invention, wherein the resin further contains a structural unit represented by the following formula (4); (In the above formula (4), R ¹ represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a hydroxyl group, a substituted hydroxyalkyl group having 1 to 6 carbon atoms, and a carbon number. 1 to 20 substitutable alkoxy group, 1 to 6 carbon atom-substituted alkylthio group, aralkylthio group or arylthio group, amine group, substituted alkyl group having 1 to 6 carbon atoms An amine group, an aralkylamino group or an arylamine group, a halogen atom, or a substitutable aryl group having 7 to 20 carbon atoms; x is an integer of 1 to 6, an integer of y is 0 to 2, and x is 2 or more. In time, the lines R ¹ may be the same or different, respectively. The composition for a photoresist base film according to the first aspect of the invention, further comprising at least one selected from the group consisting of an acid generator and a crosslinking agent. A method for forming a dual damascene structure, comprising the step of: forming on a photoresist base film formed by using the composition for a photoresist base film according to any one of claims 1 to 5; a photoresist pattern having a photoresist pattern as a mask, wherein the photoresist pattern of the photoresist film is transferred to the photoresist underlayer film by etching; and the photoresist is transferred using the photoresist film The aforementioned photoresist bottom a step of transferring the photoresist pattern of the photoresist underlayer film on the low dielectric insulating film disposed under the photoresist underlayer film as a mask; transferring the low dielectric insulating film After the photoresist pattern of the photoresist underlayer film, the step of removing the photoresist underlayer film by plasma ashing is performed. The method for forming a dual damascene structure according to claim 6, wherein the gas used for the plasma ashing is a mixed gas of ammonia, nitrogen and hydrogen.