9,9-bis(hydroxynaphthyl)-diarylethene condensates, methods for their manufacture, and compositions for hardmasks

Abstract

Provided is a novel 9,9-bis(hydroxynaphthyl)-dialkyldifluorene condensate having high heat resistance, represented by a novel 9,9-bis(hydroxynaphthyl)-diaryldifluorene condensate. A 9,9-bis(hydroxynaphthyl)-diaryldifluorene condensate containing a monomer unit derived from 9,9-bis(hydroxynaphthyl)-diaryldifluorene.

Description

Technical Field

[0001] This invention relates to 9,9-bis(hydroxynaphthyl)-diarylfluorene condensates, methods for their manufacture, and compositions for hard masks. Background Technology

[0002] For example, Patent Document 1 discloses a method for forming a photoresist underlayer film, which is a method for forming a photoresist underlayer film of at least three layers of multilayer photoresist film used in photolithography processes. The method is characterized by comprising the following steps: coating a photoresist underlayer film material on a substrate, the photoresist underlayer film material containing a resin obtained by phenolic varnishing of a compound having a bis-naphthol group; and heat-treating the coated photoresist underlayer film material at a temperature exceeding 300°C and below 600°C for a range of 10 seconds to 600 seconds to cure it.

[0003] Furthermore, Patent Document 2 describes a lower film forming material obtained by adding a phenolic varnish resin having a fluorene or tetrahydrospirodiinden structure. The lower film forming material described in Patent Document 2 is used to form a lower film, which is disposed below a photoresist layer used for processing a substrate. The desired area of ​​the photoresist layer is irradiated with radiation, and developed with a developer to form a photoresist pattern. The lower film layer and the substrate are then processed in a dry etching apparatus using this photoresist pattern layer as a mask.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2010-122656 Patent Document 2: Japanese Patent Application Publication No. 2005-128509 Summary of the Invention The problem that the invention aims to solve The materials described in Patent Documents 1 and 2 are used to form hard masks in the microfabrication of semiconductors. For example, spin-coated glass (SOG) films can be formed on hard masks formed from these materials. However, during the formation of the spin-coated glass film, the hard mask may be exposed to high temperatures. Therefore, there is a need for a material with higher heat resistance than the materials described in Patent Documents 1 and 2.

[0005] One aspect of the present invention is to provide a novel 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate with high heat resistance, represented by a novel 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate, and related technologies thereof.

[0006] Methods for solving problems To address the aforementioned issues, one aspect of the present invention relates to a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0007] Additionally, one aspect of the present invention relates to a composition for a hard mask comprising the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate as described in one aspect of the present invention.

[0008] In addition, one aspect of the present invention relates to a method for producing a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate, comprising the following steps: in the presence of an acid catalyst or a base catalyst, controlling the molar ratio of aldehyde to monomer in the range of 0.30 to 0.90, reacting the monomer with the aldehyde to produce a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate; wherein the monomer is selected from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene and 9,9-bis(hydroxynaphthyl)-diphenylfluorene.

[0009] The effects of the invention According to one aspect of the present invention, it is possible to provide novel 9,9-bis(hydroxynaphthyl)-diarylfluorene condensates with high heat resistance, represented by novel 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates, and related technologies thereof. Detailed Implementation

[0010] <Terminology> When used in this specification, the numerical range represented by "~" refers to the range that includes the values ​​before and after "~" as the minimum and maximum values, respectively.

[0011] [1] 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate contains a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0012] The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate can be a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate containing a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene; it can also be a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate containing a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diphenylfluorene; or it can be a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate containing monomeric units derived from 9,9-bis(hydroxynaphthyl)-diphenylfluorene. More specifically, the condensate is a resin formed by the independent polycondensation of at least one of the two naphthol groups attached to the 9 position of the fluorene group via a methylene group, and two aryl groups are bonded in addition to the 9 position of the fluorene group. Thus, the heat resistance of the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate is improved.

[0013] The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate preferably has aryl groups at any two of the 1 to 8 positions other than the 9 position of the fluorene group, and more preferably has aryl groups at the 2 and 7 positions.

[0014] The monomer unit of the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate is preferably a monomer unit having the structure shown in formula (I) below: Formula (I).

[0015] In the formula (I), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; Ar is independently selected from phenyl, 1-naphthyl, and 2-naphthyl; n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0016] [1-1] 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomer unit having the structure shown in formula (I) above, preferably a 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate comprising a monomer unit having the structure shown in formula (1) or formula (2) below.

[0017] 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate is a condensate comprising a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene. More specifically, the condensate is a resin formed by the independent polycondensation of at least one of the two naphthol groups attached at the 9-position of the fluorene group via a methylene group, and two additional naphthyl groups are bonded outside the 9-position of the fluorene group.

[0018] The 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate has two additional naphthyl groups attached at the 9-position of the fluorene group constituting the monomer unit, thereby improving its heat resistance.

[0019] 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate can be 9,9-bis(hydroxynaphthyl)-bis(2-naphthyl)fluorene condensate, wherein the monomer unit is preferably a monomer unit having the structure shown in the following formula (1): Equation (1).

[0020] In the formula (1), preferably, R1 is independently selected from alkyl groups having 1 to 4 carbon atoms, where the alkyl group can be a straight-chain or branched alkyl group; n is independently an integer of 1 or 2; m is independently an integer of 0 or 1. The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0021] Furthermore, the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate containing a monomer unit having the structure shown in formula (I) above can be a 9,9-bis(hydroxynaphthyl)-bis(1-naphthyl)fluorene condensate, wherein the monomer unit is preferably a monomer unit having the structure shown in formula (2) below: Equation (2).

[0022] In the formula (2), preferably, R1 is independently selected from alkyl groups having 1 to 4 carbon atoms, where the alkyl group can be a straight-chain or branched alkyl group; n is independently an integer of 1 or 2; m is independently an integer of 0 or 1. The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0023] The 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate comprises a monomer unit having the structure shown in formula (1) above. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate is preferably selected from: 9,9-bis(hydroxynaphthyl)-di(2-naphthyl)fluorene condensate; and 9,9-bis(hydroxynaphthyl)-di(1-naphthyl)fluorene condensate comprising a monomer unit having the structure shown in formula (1) above.

[0024] [1-2] 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensate The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomer unit having the structure shown in formula (I) above is preferably a 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensate comprising a monomer unit having the structure shown in formula (3) below.

[0025] Equation (3) In the above equation (3), n is an integer of 1 or 2, respectively; m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to other monomer units via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0026] n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to other monomer units via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0027] The 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensate has two phenyl groups bonded at the 2 and 7 positions of the fluorene group constituting the monomer unit, thereby improving its heat resistance.

[0028] [1-3] Weight-average molecular weight, etc. Regarding 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates and 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensates, the weight-average molecular weight (Mw) is preferably 15,000 or less, more preferably 7,000 or less, and even more preferably 5,000 or less. The Mw of the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate is preferably 1,000 or more, more preferably 2,000 or more, thereby further improving the heat resistance and, for example, the durability against fluorine-based etchants. Furthermore, since the Mw of the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate is 15,000 or less, it is easier to fill the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate into the steps of a stepped substrate.

[0029] Furthermore, for 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates and 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensates, the dispersibility (Mw / Mn) is preferably in the range of 1.0 to 3.5. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates can be obtained by gel permeation chromatography (GPC) analysis using standard polystyrene, and the Mw / Mn is calculated based on the weight-average molecular weight (Mw) and number-average molecular weight (Mn) obtained by GPC analysis.

[0030] Furthermore, the Onishi parameter of 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates, etc., is preferably 2.0 or less, more preferably 1.8 or less, and this parameter is calculated by the following formula: Western parameter = N / (NC – NO) In the above formula, N represents the total number of atoms constituting the compound, NC represents the total number of carbon atoms constituting the compound, and NO represents the total number of oxygen atoms constituting the compound.

[0031] The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate has a datum parameter of 2.0 or less, thereby improving its durability against etchants used in dry etching, for example.

[0032] Furthermore, the ring parameter of 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates, etc., is preferably 0.85 or more, more preferably 0.87 or more, and this parameter is calculated by the following formula: Ring parameter = M CYCLO / M In the above formula, M represents the molecular weight of the compound. CYCLO It represents the total atomic weight of carbon atoms in the cyclic structure of a compound.

[0033] The ring parameter of the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate is 0.87 or higher, thereby improving its durability against etchants used in dry etching, for example.

[0034] 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates and 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensates, etc., are 9,9-bis(hydroxynaphthyl)-diarylfluorene condensates, which can be obtained by reacting a monomer with an aldehyde in the presence of an acid catalyst or a base catalyst. The condensate is a resin formed by the polycondensation of 9,9-bis(hydroxynaphthyl)-diarylfluorene via a methylene group derived from an aldehyde. Here, the monomer is at least one monomer selected from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0035] In this specification, for convenience, unless otherwise stated, naphthol resin means 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate, exemplified by 9,9-bis(hydroxynaphthyl)-diphenylfluorene condensate; here, naphthol resin means naphthol phenolic varnish resin or naphthol methyl phenolic resin.

[0036] [2] Method for preparing 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate A method for manufacturing naphthol resin, specifically 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate, includes the following steps: reacting a monomer with an aldehyde in the presence of an acid catalyst or a base catalyst to produce the naphthol resin. Here, the monomer can be 9,9-bis(hydroxynaphthyl)-diarylfluorene, preferably selected from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene and 9,9-bis(hydroxynaphthyl)-diphenylfluorene.

[0037] [2-1] 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene The monomer used to obtain naphthol resin, 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene, is a compound in which two naphthol groups (hydroxynaphthyl) are bonded at the 9 position of the fluorene group, and naphthyl groups are present at any two of the 1 to 8 positions of the fluorene group.

[0038] More specifically, 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene more preferably has the structure shown in formula (1a): Equation (1a).

[0039] In formula (1a), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is independently an integer of 1 or 2; and m is independently an integer of 0 or 1. Here, R1, i.e., alkyl groups having 1 to 4 carbon atoms, can be straight-chain or branched alkyl groups.

[0040] Furthermore, more specifically, 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene more preferably has the structure shown in formula (2a): Equation (2a).

[0041] In formula (2a), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is independently an integer of 1 or 2; and m is independently an integer of 0 or 1. Here, R1, i.e., alkyl groups having 1 to 4 carbon atoms, can be straight-chain or branched alkyl groups.

[0042] More specifically, the monomers are preferably, for example, 9,9-bis(6-hydroxy-2-naphthyl)-2,7-di(2-naphthyl)fluorene, 9,9-bis(6-hydroxy-2-naphthyl)-2,7-di(1-naphthyl)fluorene, 9,9-bis(5-hydroxy-1-naphthyl)-2,7-di(2-naphthyl)fluorene, and 9,9-bis(5-hydroxy-1-naphthyl)-2,7-di(1-naphthyl)fluorene.

[0043] The monomers shown in formulas (1a) and (2a) preferably have two naphthol groups at positions 6 to 8, and more preferably at position 6.

[0044] [2-2] 9,9-bis(hydroxynaphthyl)-diphenylfluorene The monomer used to obtain naphthol resin, 9,9-bis(hydroxynaphthyl)-diphenylfluorene, is a compound in which two naphthol groups (hydroxynaphthyl) are bonded at the 9 position of the fluorene group, and phenyl groups are present at any two of the 1 to 8 positions of the fluorene group.

[0045] More specifically, 9,9-bis(hydroxynaphthyl)-diphenylfluorene more preferably has the structure shown in formula (3a): Equation (3a).

[0046] In formula (3a), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is independently an integer of 1 or 2; and m is independently an integer of 0 or 1. Here, R1, i.e., alkyl groups having 1 to 4 carbon atoms, can be straight-chain or branched alkyl groups.

[0047] More specifically, the monomer is preferably, for example, 9,9-bis(6-hydroxy-2-naphthyl)-2,7-diphenylfluorene or 9,9-bis(5-hydroxy-1-naphthyl)-2,7-diphenylfluorene.

[0048] The monomer shown in formula (3a) has two naphthol groups, preferably each having a hydroxyl group at the 6-8 position, and more preferably having a hydroxyl group at the 6 position.

[0049] [2-3] Aldehydes The aldehyde used in the reaction to obtain naphthol resin can be at least one compound selected from the group consisting of compounds having a formyl group and their polymers, such as formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, and glyoxal. Aldehydes can be used alone or in combination of two or more. Preferably, aldehydes are selected from formaldehyde and paraformaldehyde.

[0050] Regarding the molar ratio of aldehyde to monomer used to obtain naphthol resin, from the perspective of reducing the amount of aldehyde used, it is preferably 0.30 or more, more preferably 0.40 or more; and from the perspective of suppressing gelation during the reaction, it is preferably 0.90 or less, more preferably 0.80 or less.

[0051] [2-4] Reaction solvent Examples of reaction solvents used to obtain naphthol resin include: water; alcohols such as methanol, ethanol, propanol, and butanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; esters such as propylene glycol methyl ether acetate (PEGMEA) and γ-butyrolactone; and mixtures of these reaction solvents. Preferably, 100 to 500 parts by mass of the reaction solvent are used relative to 100 parts by mass of 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0052] Naphthol resins can be obtained by reacting 9,9-bis(hydroxynaphthyl)-diarylfluorene with aldehydes under acid or base catalysts. Examples of acid catalysts include inorganic acids, organic acids, and organic acid salts; examples of inorganic acids include hydrochloric acid, sulfuric acid, and phosphoric acid; examples of organic acids include oxalic acid, acetic acid, citric acid, tartaric acid, benzoic acid, and p-toluenesulfonic acid; examples of organic acid salts include zinc acetate and zinc borate. These acid catalysts can be used alone or in combination.

[0053] The amount of acid catalyst used in the reaction to obtain naphthol resin is preferably 0.05 to 10.0 parts by mass relative to 100 parts by mass of 9,9-bis(hydroxynaphthyl)-diarylfluorene, more preferably 0.5 to 5.0 parts by mass.

[0054] Various alkaline substances can be used as alkaline catalysts for obtaining naphthol resin. Specific examples include inorganic and organic alkaline substances; inorganic alkaline substances include alkali metal compounds, alkaline earth metal compounds, and ammonia; alkali metal compounds include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, and alkali metal salts such as sodium carbonate; alkaline earth metal compounds include hydroxides and oxides of calcium, magnesium, and barium. Organic alkaline substances include tertiary amines such as triethylamine and trimethylamine, and cyclic amines such as DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and DBN (1,5-diazabicyclo[4.3.0]non-5-ene). These alkaline catalysts can be used alone or in combination. By reacting under an alkaline catalyst, the hydroxymethyl group can be easily retained in the naphthol resin obtained after the reaction.

[0055] The amount of alkaline catalyst used in the reaction to obtain naphthol resin is preferably 0.05 to 2.00 parts by mass relative to 100 parts by mass of 9,9-bis(hydroxynaphthyl)-diarylfluorene, more preferably 0.10 to 1.00 parts by mass.

[0056] The preferred reaction temperature for obtaining the naphthol resin is 80-110°C, more preferably 90-100°C. A sufficient reaction rate can be obtained at a reaction temperature above 80°C, while a temperature below 110°C offers the advantage of easy reaction control. Furthermore, the reaction time can be set, for example, to 3-10 hours.

[0057] The resulting naphthol resin can be washed with deionized water and pure water to remove acid or base catalysts. Alternatively, the naphthol resin can be purified by methods such as reprecipitation with hydrocarbon solvents such as hexane.

[0058] <Composition for Hard Masks> According to one aspect of the present invention, 9,9-bis(hydroxynaphthyl)-dinaphthyl fluorene condensates and 9,9-bis(hydroxynaphthyl)-diphenyl fluorene condensates, etc., are naphthol resins selected from naphthol phenolic varnish resins or naphthol methyl phenolic resins, and also have two naphthyl groups bonded at the 9-position of the fluorene group constituting the monomer unit, thereby improving their heat resistance. Therefore, they can be used as resins contained in compositions for hard masks.

[0059] The composition for hard masks preferably comprises the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate as described in one aspect of the present invention, and also comprises an organic solvent. Furthermore, without impairing the effects of the present invention, the composition for hard masks may also comprise a crosslinking agent, a crosslinking accelerator, and other additives.

[0060] Crosslinking agents can be polyvalent alcohol compounds, including: melamine compounds, guanidine compounds, glycourea compounds and urea compounds, epoxy compounds, thioepoxide compounds, isocyanate compounds, and compounds with unsaturated double bond groups such as alkenyl ether groups, which are substituted with at least one group selected from hydroxymethyl, alkoxymethyl and acyloxymethyl groups. They can also be polyvalent alcohol compounds.

[0061] In addition, crosslinking accelerators can include acid-producing agents, which can be any known acid-producing agent, such as onium salt-based acid-producing agents, diazomethane derivatives, nitrobenzyl sulfonate derivatives, and disulfonic acid-based acid-producing agents. Acid-producing agents can be used alone or in combination of two or more.

[0062] Examples of onium salt-based acid-producing agents include: ammonium salts such as tetramethylammonium trifluoromethanesulfonate; iodonium salts such as diphenyliodonium trifluoromethanesulfonate and (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate; and sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate and bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate.

[0063] Examples of diazomethane derivatives include: bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, and other bisarylsulfonyl diazomethanes; and bis(cyclohexylsulfonyl)diazomethane, and other dialkylsulfonyl diazomethanes.

[0064] Other examples of acid-producing agents include: nitrobenzyl sulfonate derivatives such as 2,6-dinitrobenzyl p-toluenesulfonic acid and 2,4-dinitrobenzyl p-toluenesulfonic acid; disulfonic acid derivatives such as bis(naphthylsulfonylmethane); and sulfonate derivatives of N-hydroxyimide compounds such as N-hydroxysuccinimide methanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide p-toluenesulfonate, and N-hydroxynaphthylimide methanesulfonate.

[0065] To improve coating workability, the hard mask composition may contain an organic solvent (diluent). Since this organic solvent can be the same as the reaction solvent used to obtain the naphthol resin, its description is omitted. The concentration of naphthol resin in the hard mask composition is preferably in the range of 1 to 30% by mass, more preferably in the range of 10 to 25% by mass. This allows the naphthol resin to better fill the steps of the substrate, thereby forming a hard mask.

[0066] As a composition for hard masks, it may also contain other additives such as surfactants and plasticizers.

[0067] The hard mask composition according to one aspect of the present invention is preferably used as a composition for forming a hard mask layer (hard mask) in a multilayer resist film used in a photolithography process for the purpose of microfabrication on a substrate.

[0068] The multilayer resist film may be, for example, a three-layer resist film, comprising: a hard mask layer (lower layer) formed on the surface to be processed of the substrate; an anti-reflective layer (intermediate layer) formed on the hard mask layer; and a resist layer (upper layer) formed on the anti-reflective layer.

[0069] Regarding the substrate to be processed, steps of varying heights are sometimes formed along the thickness direction of the substrate. For example, unevenness may be formed at different heights by the gate or fin that constitutes the semiconductor element. Such substrates are sometimes called stepped substrates. The substrate can be a silicon wafer substrate, but it is not limited to this; for example, it can also be a compound semiconductor such as SiC or SiN.

[0070] The hard mask layer formed by the hard mask composition fills the steps of the substrate and covers the surface of the substrate to be processed, thereby enabling the formation of a hard mask layer with a flat surface on one side of the substrate to be processed.

[0071] The composition for hard masks can be applied to the surface of a substrate to be processed using known coating methods such as spin coating, and then dried in a heated environment to remove organic solvents. Heating and drying can be performed at 90–130°C in an inert gas atmosphere.

[0072] The thickness of the hard mask layer can be designed appropriately according to the height of the step formed on the substrate and should not be limited, but can be 600~1400 nm, preferably 800~1200 nm.

[0073] By covering the steps of the substrate with a hard mask layer with a flat surface, thickness fluctuations in the anti-reflective layer formed by CVD and ALD on the hard mask layer can be prevented in the thickness direction of the substrate. In other words, since the anti-reflective layer is formed with a uniform thickness, it is not suitable to fill the steps of the substrate without forming a hard mask layer. However, by filling the stepped substrate with a hard mask layer, the thickness of the anti-reflective layer in the thickness direction of the stepped substrate can be kept uniform. By forming a hard mask layer with a flat surface, thickness fluctuations in the anti-reflective layer and resist layer formed on it can be suppressed, thereby increasing the depth of focus in the photolithography process and improving the process margin.

[0074] Antireflective layers formed by CVD and ALD include, for example, silicon oxide (SiO), silicon nitride (SiN), and silicon oxynitride (SiON). The hard mask composition contains the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate as described in one aspect of this invention, thereby improving its heat resistance. That is, when an antireflective layer is formed on a hard mask layer formed from the hard mask composition, its heat resistance to substrate temperatures up to 300-500°C is improved. However, this is not a limitation; the antireflective film can also be formed by spin-coating a composition containing polysilsesquioxane.

[0075] As the resist layer formed on the anti-reflective layer, any type of resist, whether positive or negative, can be used, and a known photoresist composition can be employed. The thickness of the resist layer is not limited, as long as it is set according to the type of photoresist composition, but can be 30-500 nm, preferably 50-400 nm. With a multilayer resist film formed on the anti-reflective layer, high-precision patterning can be achieved even on substrates with steps of varying heights.

[0076] Exposure for patterning the resist layer can be performed using high-energy rays with wavelengths below 300 nm, such as excimer lasers at 248 nm, 193 nm, and 157 nm, soft X-rays of 3–20 nm, electron beams, or other X-rays. The desired pattern can be developed by cleaning the resist layer with a cleaning solution after exposure.

[0077] The antireflective layer can be etched using the resist layer with the pattern developed as a mask. Etching of the antireflective layer can be performed, for example, by dry etching, using fluorocarbon gases such as CF4, CHF3, and C2F6 as the etchant. The hard mask layer formed from the hard mask composition contains the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate as described in one aspect of the invention, thereby improving the residual film yield after dry etching. Therefore, distortion of the hard mask layer that may occur due to exposure to the etchant can be prevented, thereby preventing deformation of the pattern formed on the antireflective layer.

[0078] After the desired pattern is formed on the anti-reflective layer, the pattern is formed on the hard mask layer, for example by plasma etching using oxygen and hydrogen as etchants.

[0079] After the desired pattern is formed on the hard mask layer, the pattern is formed on the workpiece by plasma etching, for example, by using Freon-based gases such as CF4, CHF3, and C2F6 as etchants.

[0080] Then, for example, the multilayer resist film can be peeled off by immersing the substrate in a stripping solution, and cleaned by ashing, for example, with oxygen plasma. Thus, residues of the multilayer resist film can be removed from the substrate on which wiring is patterned.

[0081] [Overview] The first aspect of the present invention relates to a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0082] Furthermore, according to the first aspect described above, in the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate of the second aspect of the present invention, the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate is a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate containing a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

[0083] Furthermore, according to the first or second aspect described above, in the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to the third aspect of the present invention, the monomer unit is preferably a monomer unit having the structure shown in the following formula (I): Formula (I).

[0084] Here, in formula (I), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; Ar is independently selected from phenyl, 1-naphthyl, and 2-naphthyl; n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0085] Furthermore, according to the third aspect described above, in the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to the fourth aspect of the present invention, the monomer unit is preferably a monomer unit having the structure shown in the following formula (1): Equation (1).

[0086] Here, in formula (1), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

[0087] Furthermore, according to any one of the first to fourth aspects described above, in the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to the fifth aspect of the present invention, the monomer unit is preferably a monomer unit derived from 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene.

[0088] Furthermore, according to any one of the first to fifth aspects described above, the weight-average molecular weight (Mw) of the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate involved in the sixth aspect of the present invention is preferably in the range of 1,000 to 15,000.

[0089] Furthermore, according to the second or fourth aspect described above, the weight-average molecular weight (Mw) of the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate involved in the seventh aspect of the present invention is preferably in the range of 1,000 to 15,000.

[0090] Furthermore, the eighth aspect of the present invention relates to a composition for a hard mask comprising the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate as described in any one of the first to seventh aspects above.

[0091] Furthermore, a ninth aspect of the present invention relates to a method for manufacturing a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate, comprising the following steps: in the presence of an acid catalyst or a base catalyst, controlling the molar ratio of aldehyde to monomer in the range of 0.30 to 0.90, reacting the monomer with the aldehyde to produce a 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensate; wherein the monomer is selected from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene and 9,9-bis(hydroxynaphthyl)-diphenylfluorene.

[0092] Furthermore, according to the ninth aspect described above, in the method for manufacturing the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to the tenth aspect of the present invention, the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene preferably has the structure shown in the following formula (1a): Equation (1a).

[0093] In formula (1a), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is an integer that is either 1 or 2, and each of them is an independent integer. m can be an integer that is either 0 or 1, respectively.

[0094] This invention is not limited to the embodiments described above. Various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of this invention.

[0095] Example An embodiment of the present invention will now be described.

[0096] [1] Analytical methods [1-2] Gel permeation chromatography (GPC) analysis The reaction products of Examples 1-5 and Comparative Examples 1 and 2 were diluted with THF to a concentration of 0.1% and used as samples for GPC determination.

[0097] The obtained GPC test samples were subjected to GPC testing under the following test conditions. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polystyrene were calculated based on the results, and the dispersity (Mw / Mn) was evaluated.

[0098] GPC measuring device: HCL-8120GPC (manufactured by Tosoh Corporation) Chromatographic column: TSKgel G3000HXL 7.8×300mm × 1 piece (manufactured by Tosoh Corporation) TSKgel G2000HXL 7.8×300mm × 2 pieces (manufactured by Tosoh Corporation) "TSKgel" is a registered trademark of the company. Column temperature: 40℃ Detector: RI (Differential Refractive Index Detector) Solvent: THF Flow rate: 0.800 mL / min Standard polystyrene: PSt Quick E (manufactured by Tosoh Corporation) PSt Quick F (manufactured by Tosoh Corporation) [2] Synthesis of phenolic varnish resin of 9,9-bis(hydroxynaphthyl)-diarylfluorene [Example 1] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene (manufactured by Osaka Gas Chemical Co., Ltd.), 0.549 g of 37% formaldehyde aqueous solution, and 0.33 g of oxalic acid were added, and the mixture was stirred at 100 °C for 6 hours. After the reaction, the fluorene was dissolved in 20 g of methyl isobutyl ketone, and the catalyst and metal impurities were removed by thorough washing with water. The solvent was then removed under reduced pressure. Next, methoxypropyl acetate (PEGMEA) was added, and the mixture was concentrated under reduced pressure to obtain a 20% (w / w) solution of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene condensate. GPC analysis showed a weight-average molecular weight (Mw) of 2885 and an Mw / Mn ratio of 1.28.

[0099] [Example 2] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene, 0.415 g of 37% formaldehyde aqueous solution, and 0.125 g of oxalic acid were added, and the mixture was stirred at 100 °C for 6 hours. After the reaction, the acid in the reaction product was removed following the same procedure as in Example 1. Then, methoxypropyl acetate (PEGMEA) was added and the mixture was concentrated under reduced pressure to obtain a 20% by weight solution of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene condensate. GPC analysis showed a weight-average molecular weight (Mw) of 2088 and an Mw / Mn ratio of 1.18.

[0100] [Example 3] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene, 0.646 g of 37% formaldehyde aqueous solution, and 0.125 g of oxalic acid were added, and the reaction was carried out at 100 °C for 6 hours. After the reaction, the acid contained in the reaction product was removed following the same procedure as in Example 1. Then, methoxypropyl acetate (PEGMEA) was added and the mixture was concentrated under reduced pressure to obtain a 20% by weight solution of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene condensate. GPC analysis showed that the weight-average molecular weight (Mw) was 3912 and the Mw / Mn ratio was 1.47.

[0101] [Example 4] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(1-naphthyl)fluorene (manufactured by Osaka Gas Chemical Co., Ltd.), 0.549 g of 37% formaldehyde aqueous solution, and 0.44 g of oxalic acid were added, and the mixture was stirred at 100 °C for 6 hours. After the reaction, the fluorene was dissolved in 20 g of methyl isobutyl ketone, and the catalyst and metal impurities were removed by thorough washing with water. The solvent was then removed under reduced pressure. Next, methoxypropyl acetate (PGMEA) was added, and the mixture was concentrated under reduced pressure to obtain a 20% (w / w) solution of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(1-naphthyl)fluorene condensate. GPC analysis showed a weight-average molecular weight (Mw) of 2823 and an Mw / Mn ratio of 1.27.

[0102] [Example 5] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-diphenylfluorene (manufactured by Osaka Gas Chemical Co., Ltd.), 0.700 g of 37% formaldehyde aqueous solution, and 0.66 g of oxalic acid were added, and the mixture was stirred at 100 °C for 6 hours. After the reaction, the mixture was dissolved in 20 g of methyl isobutyl ketone, and the catalyst and metal impurities were removed by thorough washing with water. The solvent was then removed under reduced pressure. Next, methoxypropyl acetate (PGMEA) was added, and the mixture was concentrated under reduced pressure to obtain a 20% (w / w) solution of 9,9-bis(6-hydroxy-2-naphthyl)-2,7-diphenylfluorene condensate. GPC analysis showed a weight-average molecular weight (Mw) of 2997 and an Mw / Mn ratio of 1.32.

[0103] [Comparative Example 1] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 6,6'-(9H-fluorene-9,9-diyl)bis(naphthalene-2-ol), 1.069 g of 37% formaldehyde aqueous solution, and 0.33 g of oxalic acid were added, and the reaction was carried out at 100 °C for 6 hours. After the reaction, the acid contained in the reaction product was removed following the same procedure as in Example 1. Then, methoxypropyl acetate (PEGMEA) was added and the mixture was concentrated under reduced pressure to obtain a 20% by mass solution of the 6,6'-(9H-fluorene-9,9-diyl)bis(naphthalene-2-ol) condensate. GPC analysis showed that the weight-average molecular weight (Mw) was 2500 and the Mw / Mn ratio was 1.20.

[0104] [Comparative Example 2] In a 200 mL reaction vessel equipped with a thermometer, condenser, and magnetic stirrer, 8.0 g of 9,9-bis(4-hydroxyphenyl)fluorene, 1.770 g of 37% formaldehyde aqueous solution, and 0.558 g of oxalic acid were added, and the reaction was carried out at 100 °C for 8 hours. After the reaction, the acid contained in the reaction product was removed following the same procedure as in Example 1. Then, methoxypropyl acetate (PEGMEA) was added and the mixture was concentrated under reduced pressure to obtain a 20% by mass solution of 9,9-bis(4-hydroxyphenyl)fluorene condensate. GPC analysis showed that the weight-average molecular weight (Mw) was 12600 and the Mw / Mn ratio was 4.15.

[0105] [3] Evaluation methods [3-1] Atlantean parameters The Atlantean parameter is calculated using the following formula.

[0106] Western parameter = N / (NC – NO) In the above formula, N represents the total number of atoms constituting the compound, NC represents the total number of carbon atoms constituting the compound, and NO represents the total number of oxygen atoms constituting the compound. The N, NC, and NO values ​​of the compounds used to calculate the Onishi parameters are obtained based on the structure of the condensate.

[0107] [3-2] Ring parameters The ring parameters are calculated using the following formula.

[0108] Ring parameter = M CYCLO / M In the above formula, M represents the molecular weight of the compound. CYCLO This represents the total atomic weight of carbon atoms in the ring structure of the compound. The M value of the compound used to calculate the ring parameter is determined based on the structure of the condensate. CYCLO .

[0109] [3-3] Evaluation of residual film rate (etch resistance) The residual film rate was evaluated for Examples 1-3 and Comparative Examples 1 and 2. The residual film rate was evaluated by measuring the proportion of organic film remaining on the silicon substrate after dry etching.

[0110] In sample preparation, the compound was spin-coated onto a silicon substrate (10.16 cm in diameter), and then the coated silicon substrate was baked on a hot plate at 350°C for 60 seconds. This resulted in an organic film with a thickness of 1000 nm on the silicon substrate. This organic film was used as the sample for determining the residual film rate.

[0111] The dry etching conditions used to evaluate the residual film yield are as follows: Equipment: Compact etching machine FA-1-TK (manufactured by Samco Corporation) RF power: 200W CF4 gas flow rate: 20 sccm (mL / min) Dry etching time: 120 seconds The etched film thickness was measured using an F20-UV (film thickness measurement system; manufactured by Filmetrics Co., Ltd.).

[0112] The residual film rate is measured as the proportion of organic film remaining on the silicon substrate after dry etching.

[0113] Residual film rate = b / a × 100 The film thickness before etching is set as the film thickness a of the organic film, and the film thickness after etching is set as the film thickness b.

[0114] [3-4] Evaluation of thermal decomposition temperature The resin compounds obtained in Examples 1-5 and Comparative Examples 1 and 2 were redeprecipitated with hexane and used as test samples to evaluate the thermal decomposition temperature.

[0115] Differential thermal / thermogravimetric synchronous measurement device: STA200RV (manufactured by Hitachi High Technology Co., Ltd.) The thermal decomposition temperature of the resin was determined by measuring the thermal weight loss in the range of 50~700℃ under atmospheric conditions with a heating rate of 10℃ / min.

[0116] [4] Evaluation Results Table 1 below shows the evaluation results of the resin compounds of Examples 1-5 and Comparative Examples 1 and 2.

[0117] [Table 1]

[0118] As the evaluation results above show, the 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene condensates of Examples 1 to 5 have high residual film rates and high thermal decomposition temperatures of over 500°C in Examples 1 to 3 and over 400°C in Examples 4 and 5. Thus, it is confirmed that they are suitable for use as hard masks in multilayer resist films.

[0119] Industrial availability This invention can be used, for example, as a hard mask for multilayer resist films used in the microfabrication of semiconductor devices.

Claims

1. A 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

2. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to claim 1, wherein it is a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate comprising a monomeric unit derived from 9,9-bis(hydroxynaphthyl)-diarylfluorene.

3. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to claim 1 or 2, wherein, The single-unit is a single-unit having the structure shown in the following formula (I): Equation (I); In the formula (I), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; Ar is independently selected from phenyl, 1-naphthyl, and 2-naphthyl; n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

4. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to claim 3, wherein, The single-unit is a single-unit having the structure shown in equation (1) below: Equation (1); In the formula (1), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is an integer that is either 1 or 2, and each of them is an independent integer. m are independent integers of 0 or 1; The term "bonding bond" indicates that at least one of the bonding bonds is bonded to the other monomeric unit via a methylene group, and the remaining bonding bonds are bonded to hydrogen or hydroxymethyl groups.

5. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to any one of claims 1 to 4, wherein, The monomer unit is a monomer unit derived from 9,9-bis(6-hydroxy-2-naphthyl)-2,7-bis(2-naphthyl)fluorene.

6. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to any one of claims 1 to 5, wherein the weight-average molecular weight (Mw) is in the range of 1,000 to 15,000.

7. The 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to claim 2 or 4, wherein the weight-average molecular weight (Mw) is in the range of 1000 to 15000.

8. A composition for a hard mask comprising the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to any one of claims 1 to 7.

9. A method for manufacturing a 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate, comprising the following steps: In the presence of an acid catalyst or a base catalyst, the molar ratio of aldehyde to monomer is controlled in the range of 0.30 to 0.90, so that the monomer reacts with the aldehyde to produce 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate. The monomer is selected from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene and 9,9-bis(hydroxynaphthyl)-diphenylfluorene.

10. The method for manufacturing the 9,9-bis(hydroxynaphthyl)-diarylfluorene condensate according to claim 9, wherein, The monomer is selected from 9,9-bis(hydroxynaphthyl)-dinaphthylfluorene having the structure shown in formula (1a) below: Equation (1a); In formula (1a), R1 is independently selected from alkyl groups having 1 to 4 carbon atoms; n is an integer that is either 1 or 2, and each of them is an independent integer. m can be an integer that is either 0 or 1, respectively.

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