Patent Application
20230259031
The present invention relates to a resist underlayer film-forming composition, a resist underlayer film, which is a baked product of a coating film containing the composition, and a method for producing a semiconductor device using the composition.
In recent years, there has been a need for a resist underlayer film-forming composition for use in the lithography process of semiconductor device manufacturing that does not intermix with the upper layer, produces an excellent resist pattern, and has a smaller dry etching rate than the upper layer (hard mask: coating film or vapor-deposited film) or semiconductor substrate. And the use of a polymer having a repeating unit containing a benzene ring or a naphthalene ring has been proposed (Patent Literature 1).
Patent Literature 1: WO 2013/047516 A1
However, the conventional resist underlayer film-forming compositions are still unsatisfactory in such requirements: providing a hydrophobic underlayer film that exhibits a high contact angle with pure water and a high adhesion to the upper layer film, and robust to peeling off, as well as having a good application property. In the semiconductor manufacturing process, treatment with chemical solutions may be carried out, and in such cases, the resist underlayer film may be required to have a sufficient resistance to the chemical solutions used.
The present invention solves the above problems. That is, the present invention includes the followings.
[1] A resist underlayer film-forming composition comprising a solvent and a polymer comprising a unit structure (A) represented by the following formula (1) and/or formula (2):
wherein Ar1 and Ar2 each represent a benzene ring or naphthalene ring, Ar1 and Ar2 may be bonded via a single bond;
Ar3 represents an aromatic compound having 6 to 60 carbon atoms and optionally containing a nitrogen atom,
R1 and R2 are groups substituting hydrogen atoms on the rings of Ar1 and Ar2, respectively, and are selected from the group consisting of a halogen atom, a nitro group, an amino group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond,
R3 and R8 are selected from the group consisting of an alkyl group having 1 to carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond, and the aryl group may be substituted with an alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group;
R4 and R6 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond;
R5 and R7 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond;
R4 and R5, and R6 and R7 may be combined with a carbon atom to which they are bonded to form a ring;
n1 and n2 are each an integer of from 0 to 3;
n3 is an integer of 1 or more but not more than a number of substituent with which Ar3 can be substituted; and
n4 is 0 or 1, but when n4 is 0, R8 is bonded to a nitrogen atom contained in Ar3.
[2] The resist underlayer film-forming composition according to [1], wherein Ar3 and in formula (1) are benzene rings.
[3] The resist underlayer film-forming composition according to [1], wherein Ar3 in formula (2) is an optionally substituted benzene, naphthalene, diphenylfluorene, or phenylindole ring.
[4] The resist underlayer film-forming composition according to any one of [1] to [3], wherein in formula (1) or (2),
R4 and R6 are an aryl group having 6 to 40 carbon atoms, and
R5 and R7 are hydrogen atoms.
[5] The resist underlayer film-forming composition according to any one of [1] to [4], wherein in formula (1) or (2),
R4 and R6 are aromatic hydrocarbon groups having 6 to 16 carbon atoms.
[6] The resist underlayer film-forming composition according to any one of [1] to [5], further comprising a crosslinking agent. [7] The resist underlayer film-forming composition according to any one of [1] to [6], further comprising an acid and/or an acid generator.
[8] The resist underlayer film-forming composition according to [1], wherein the solvent has a boiling point of 160° C. or higher.
[9] A resist underlayer film, which is a baked product of a coating film comprising the resist underlayer film-forming composition according to any one of [1] to [8].
[10] A method for producing a semiconductor device, comprising the steps of:
forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 8;
forming a resist film on the formed resist underlayer film;
forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development;
etching and patterning the resist underlayer film through the formed resist pattern; and
processing the semiconductor substrate through the patterned resist underlayer film.
[11] A method for producing a semiconductor device, comprising the steps of:
forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 8;
forming a hard mask on the formed resist underlayer film;
forming a resist film on the formed hard mask;
forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development;
etching the hard mask through the formed resist pattern;
etching the resist underlayer film through the etched hard mask; and
removing the hard mask.
[12] The method for producing a semiconductor device according to [11], further comprising the steps of:
forming a vapor-deposited film (spacer) on the underlayer film from which the hard mask has been removed;
processing the formed vapor-deposited film (spacer) by etching;
removing the underlayer film; and
processing the semiconductor substrate with the spacer.
[13] The method for producing a semiconductor device according to any one of [10] to [12], wherein the semiconductor substrate is a stepped substrate.
The present invention provides a novel resist underlayer film-forming composition that can meet such requirements: providing a hydrophobic underlayer film that exhibits a high contact angle with pure water and a high adhesion to the upper layer film, and robust to peeling off, as well as having a good application property, while also exhibiting other good properties such as sufficient resistance to chemical solutions used for the resist underlayer film.
<Resist Underlayer Film-Forming Composition>
The resist underlayer film-forming composition of the present invention contains a solvent and a unit structure (A) represented by the following formula (1) and/or formula (2):
wherein Ar1 and Ar2 each represent a benzene ring or naphthalene ring, Ar1 and Ar2 may be bonded via a single bond;
Ar3 a represents an aromatic compound having 6 to 60 carbon atoms and optionally containing a nitrogen atom,
R1 and R2 are groups substituting hydrogen atoms on the rings of Ar1 and Ar2, respectively, and are selected from the group consisting of a halogen atom, a nitro group, an amino group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond,
R3 and R8 are selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond,
R4 and R6 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond,
R5 and R7 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond,
R4 and R5, and R6 and R7 may be combined with a carbon atom to which they are bonded to form a ring;
n1 and n2 are each an integer of from 0 to 3;
n3 is an integer of 1 or more but not more than a number of substituent with which Ar3 can be substituted; and
n4 is 0 or 1, but when n4 is 0, R8 is bonded to a nitrogen atom contained in Ar3.
<Polymer Containing Unit Structure (A) Represented by Formula (1) and/or Formula (2)>
Ar1 and Ar2 each represent a benzene or naphthalene ring.
Ar1 and Ar2 may be bonded via a single bond, for example, to form a carbazole skeleton.
It is preferred that both Ar1 and Ar2 are benzene rings.
Ar3 represents an aromatic compound having 6 to 60 carbon atoms that may contain a nitrogen atom. Specific examples thereof include benzene, styrene, toluene, xylene, mesitylene, cumene, indene, naphthalene, biphenyl, azulene, anthracene, phenanthrene, naphthacene, triphenylene, pyrene, chrysene, fluorene, 9,9-diphenyl fluorene, 9,9-dinaphthyl fluorene, indole, phenylindole, purine, quinoline, isoquinoline, quinuclidine, acridine, phenazine, and carbazole.
R1 and R2 are groups substituting hydrogen atoms on the rings of Ar1 and Ar2 and are selected from the group consisting of a halogen atom, a nitro group, an amino group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, wherein the alkyl, alkenyl, alkynyl and aryl groups may contain an ether, ketone, or ester bond.
R3 and R8 are selected from the group consisting of an alkyl group having 1 to carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, wherein the alkyl, alkenyl, alkynyl and aryl groups may contain an ether, ketone, or ester bond, and the aryl group may be substituted with an alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group (that is, the aryl 5 group may have a hydroxyalkyl group having 1 to 10 carbon atoms as a substituent).
When the aryl group is substituted with an alkyl group substituted with a hydroxyl group, the hydroxyl group is preferably substituted at the benzyl position. Also, the aryl group includes aromatic rings connected to each other by a methine group substituted with a hydroxyl group (that is, —Ar—C(OH)X1X2, wherein Ar is an aryl group, X1 and X2 are hydrogen atoms or any organic groups, preferably either X1 or X2 are aromatic groups).
Examples of the halogen group include fluorine, chlorine, bromine, and iodine.
Examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2 trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, and 1-ethyl-2-methyl-n-propyl groups.
The group may be a cyclic alkyl group, such as cyclopropyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclobutyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl, and 2-ethyl-3-methyl-cyclopropyl groups.
Examples of the alkenyl group having 2 to 10 carbon atoms include ethenyl, 1-propenyl, 2-propenyl, 1-methyl-1-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propyl ethenyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethyl-2 propenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 2-methyl-3-butenyl, 3-methyl-1-butenyl, 3-methyl-2-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1-i-propyl ethenyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-cyclopentenyl, 2-cyclopentenyl, 3-cyclopentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 1-methyl-2-pentenyl, 1-methyl-3-pentenyl, 1-methyl-4-pentenyl, 1-n-butylethenyl, 2-methyl-1-pentenyl, 2-methyl-2-pentenyl, 2-methyl-3-pentenyl, 2-methyl-4-pentenyl, 2-n-propyl-2-propenyl, 3-methyl-1-pentenyl, 3-methyl-2-pentenyl, 3-methyl-3-pentenyl, 3-methyl-4-pentenyl, 3-ethyl-3-butenyl, 4-methyl-1-pentenyl, 4-methyl-2-pentenyl, 4-methyl-3-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl, 1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1-methyl-2-ethyl-2-propenyl, 1-s-butylethenyl, 1,3-dimethyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 1-i-butylethenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 2-i-propyl-2-propenyl, 3,3-dimethyl-1-butenyl, 1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 1-n-propyl-1-propenyl, 1-n-propyl-2-propenyl, 2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-trimethyl-2-propenyl, 1-t-butylethenyl, 1-methyl-1-ethyl-2-propenyl, 1-ethyl-2-methyl-1-propenyl, 1-ethyl-2-methyl-2-propenyl, 1-i-propyl-1-propenyl, 1-i-propyl-2-propenyl, 1-methyl-2-cyclopentenyl, 1-methyl-3-cyclopentenyl, 2-methyl-1-cyclopentenyl, 2-methyl-2-cyclopentenyl, 2-methyl-3-cyclopentenyl, 2-methyl-4-cyclopentenyl, 2-methyl-5-cyclopentenyl, 2-methylene-cyclopentyl, 3-methyl-1-cyclopentenyl, 3-methyl-2-cyclopentenyl, 3-methyl-3-cyclopentenyl, 3-methyl-4-cyclopentenyl, 25 3-methyl-5-cyclopentenyl, 3-methylene-cyclopentyl, 1-cyclohexenyl, 2-cyclohexenyl, and 3-cyclohexenyl groups.
Examples of the alkynyl group having 2 to 10 carbon atoms include ethynyl, 1-propynyl, and 2-propynyl groups.
Examples of the aryl group having 6 to 40 carbon atoms include phenyl, benzyl, naphthyl, anthracenyl, phenanthrenyl, naphthacenyl, triphenylenyl, pyrenyl, and chrysenyl groups.
The above alkyl, alkenyl, alkynyl and aryl groups may contain an ether (—O—), ketone (—CO—), or ester (—COO—, —OCO—) bond.
R4 and R6 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, wherein the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 40 carbon atoms, and the alkyl, alkenyl, alkynyl and aryl groups may contain an ether, ketone, or ester bond.
R5 and R7 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, wherein the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and an aryl group having 6 to 40 carbon atoms, and the alkyl, alkenyl, alkynyl and aryl groups may contain an ether, ketone, or ester bond.
The heterocyclic group is a substituent derived from a heterocyclic compound, and specific examples thereof include thiophene, furan, pyridine, pyrimidine, pyrazine, pyrrole, oxazole, thiazole, imidazole, quinoline, carbazole, quinazoline, purine, indolizine, benzothiophene, benzofuran, indole, acridine, isoindole, benzoimidazole, isoquinoline, quinoxaline, cinnoline, pteridine, chromene (benzopyran), isochromene (benzopyran), xanthene, thiazole, pyrazole, imidazoline, and azine groups. Of these, thiophene, furan, pyridine, pyrimidine, pyrazine, pyrrole, oxazole, thiazole, imidazole, quinoline, carbazole, quinazoline, purine, indolizine, benzothiophene, benzofuran, indole, and acridine groups are preferred, and thiophene, furan, pyridine, pyrimidine, pyrrole, oxazole, thiazole, imidazole, and carbazole groups are most preferred.
Examples of the alkoxy group having 1 to 10 carbon atoms include groups in which an etheric oxygen atom (—O—) is bonded to the terminal carbon atom of the above-mentioned alkyl group having 1 to 10 carbon atoms. Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, i-propoxy, cyclopropoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, cyclobutoxy, 1-methyl-cyclopropoxy, 2-methyl-cyclopropoxy, n-pentoxy, 1-methyl-n-butoxy, 2-methyl-n-butoxy, 3-methyl-n-butoxy, 1,1-dimethyl-n-propoxy, 1,2-dimethyl-n-propoxy, 2,2-dimethyl-n-propoxy, 1-ethyl-n-propoxy, 1,1-diethyl-n-propoxy, cyclopentoxy, 1-methyl-cyclobutoxy, 2-methyl-cyclobutoxy, 3-methyl-cyclobutoxy, 1,2-dimethyl-cyclopropoxy, 2,3-dimethyl-cyclopropoxy, 1-ethyl-cyclopropoxy, and 2-ethyl-cyclopropoxy groups.
R4 and R5 and R6 and R7 may be combined with a carbon atom to which they are bonded to form a ring (for example, a fluorene ring).
n1 and n2 are each an integer of from 0 to 3, preferably from 0 and 2, more preferably from 0 to 1, and most preferably 0.
n3 is an integer of 1 or more, preferably 2 or more, but not more than a number of substituent with which Ar3 can be substituted, and is preferably an integer of 6 or less, more preferably 4 or less, and most preferably 2 or less.
Of the compounds represented by the above formula (1) or (2), preferred compounds are as follows.
Compounds represented by formula (1), wherein Ar1 and Ar2 are benzene rings.
Compounds represented by formula (2), wherein Ar3 is an optionally substituted benzene, naphthalene, diphenylfluorene or phenylindole ring.
Compounds represented by formula (1) or (2), wherein R4 and R6 are an aryl group having 6 to 40 carbon atoms, and R5 and R7 are hydrogen atoms.
Compounds represented by formula (1) or (2), wherein R4 and R6 are aromatic hydrocarbon groups having 6 to 16 carbon atoms.
<Solvent>
The solvent for the resist underlayer film-forming composition of the present invention is not particularly limited as long as it is a solvent that can dissolve the compound represented by the above formula (1) or (2). In particular, since the resist underlayer film-forming composition of the present invention is used in a homogeneous solution state, it is recommended that it be used in combination with a solvent commonly used in the lithography process, considering its application property.
Examples of the solvent include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoether ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxy propionate, ethyl 2-hydroxy-2-methyl propionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl pyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents may be used each alone or in combination of two or more thereof.
The following compounds listed in WO2018/131562A1 may also be used:
wherein R1, R2 and R3 in formula (i) each represent a hydrogen atom, an oxygen atom, a sulfur atom, or an alkyl group having 1 to 20 carbon atoms, which may be interrupted by an amide bond, may be identical or different from each other, and may be bonded to each other to form a ring structure.
Examples of the alkyl group having 1 to 20 carbon atoms include a linear or branched alkyl group with or without substituents, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, sohexyl, n-heptyl, n-octyl, cyclohexyl, 2-ethylhexyl, n-nonyl, isononyl, p-tert-butylcyclohexyl, n-decyl, n-dodecylnonyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl nonadecyl, nonadecyl, and eicosyl groups. Of these, an alkyl group having 1 to 12 carbon atoms are preferred, an alkyl group having 1 to 8 carbon atoms are more preferred, and an alkyl group having 1 to 4 carbon atoms are even more preferred.
Examples of the alkyl group having 1 to 20 carbon atoms interrupted by an oxygen atom, sulfur atom, or amide bond include those containing the structural unit —CH2—O—, —CH2—S—, —CH2—NHCO—, or —CH2—CONH—. There may be one or more units of —O, S, NHCO— or —CONH— in the alkyl group. Specific examples of the alkyl group having 1 to 20 carbon atoms interrupted by —O, S, NHCO—or —CONH— unit include methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, propylcarbonylamino, butylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, propylaminocarbonyl, and butylaminocarbonyl. Other examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, or octadecyl groups substituted with a methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, methylaminocarbonyl, or ethylaminocarbonyl group. Of these, methoxy, ethoxy, methylthio, and ethylthio groups are preferred, and methoxy and ethoxy groups are more preferred.
Since these solvents have a relatively high boiling point, they are also effective in imparting high embedding and high planarization properties to the resist underlayer film-forming composition.
The following are specific examples of preferred compounds represented by formula (i).
Of the above compounds, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, and compounds represented by the following formula are preferred; and the compound represented by formula (i) is particularly preferably 3-methoxy-N,N-dimethylpropionamide or N,N-dimethylisobutylamide:
These solvents may be used each alone or in combination of two or more thereof. Of these solvents, those having boiling points of 160° C. or higher are preferred, such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutylamide, 2,5-dimethylhexane-1,6-diyl diacetate (DAH; CAS 89182-68-3), and 1,6-diacetoxyhexane (CAS 6222-17-9). Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and N,N-dimethylisobutylamide are particularly preferred.
These solvents may be used each alone or in combination of two or more thereof. The solid content ratio of the composition, excluding organic solvents, is, for example, from 0.5% to 30% by mass, and preferably from 0.8% to 15% by mass.
<Optional Components>
The resist underlayer film-forming composition of the present invention may further include at least one of crosslinking agent, acid and/or acid generator, thermal acid generator, and surfactant as optional components.
(Crosslinking agent)
The resist underlayer film-forming composition of the present invention may further include a crosslinking agent. The crosslinking agent is preferably a crosslinking compound having at least two crosslink-forming substituents. Examples thereof include melamine, substituted urea, and phenol compounds having crosslink-forming substituents such as methylol and methoxymethyl groups, or their polymers. Specific examples of the compound include methoxymethylated glycoluryl, butoxymethylated glycoluryl, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, and butoxymethylated benzoguanamine, such as tetramethoxymethylglycoluril (for example, PL-LI (tetrakis(methoxymethyl)glycoluril manufactured by Midori Kagaku Co., Ltd.), tetrabutoxymethylglycoluril, and hexamethoxymethylmelamine). Examples of the substituted urea compound include methoxymethylated urea, butoxymethylated urea, and methoxymethylated thiourea, such as tetramethoxymethylurea and tetrabutoxymethylurea. Condensates of these compounds may also be used.
Examples of the phenolic compound include tetrahydroxymethylbiphenol, tetramethoxymethylbiphenol, tetrahydroxymethylbisphenol, tetramethoxymethylbisphenol, and compounds represented by the following formula:
The crosslinking agent may be a compound having at least two epoxy groups. Examples of the compound include tris(2,3-epoxypropyl)isocyanurate, 1,4-butanediol diglycidyl ether, 1,2-epoxy-4-(epoxyethyl)cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2,6-diglycidylphenyl glycidyl ether, 1,1,3-tris[p-(2,3-epoxypropoxy)phenyl]propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 4,4′-methylenebis(N,N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylol ethane triglycidyl ether, bisphenol-A-diglycidyl ether, Epolead [registered trademark] GT-401, GT-403, GT-301, GT-302, Celloxide [registered trademark] 2021, and 3000 manufactured by Daicel Corporation, 1001, 1002, 1003, 1004, 1007, 1009, 1010, 828, 807, 152, 154, 180S75, 871, and 872 manufactured by Mitsubishi Chemical Corporation, EPPN201, 202, EOCN-102, 103S, 104S, 1020, 1025, and 1027 manufactured by Nippon Kayaku Co., Ltd., Denacol [registered trademark] EX-252, EX-611, EX-612, EX-614, EX-622, EX-411, EX-512, EX-522, EX-421, EX-313, EX-314, and EX-321 manufactured by Nagase ChemteX Corporation, CY175, CY177, CY179, CY182, CY184, and CY192 manufactured by BASF Japan Ltd., and Epiclon 200, 400, 7015, 835LV, and 850CRP manufactured by DIC Corporation. The compound having at least two epoxy groups may also be an epoxy resin having an amino group. Examples of the epoxy resin include YH-434 and YH-434L (manufactured by NSCC Epoxy Manufacturing Co., Ltd.).
The crosslinking agent may be a compound having at least two blocked isocyanate groups. Examples of the compound include Takenate [registered trademark] B-830 and B-870N manufactured by Mitsui Chemicals, Inc. and VESTANAT [registered trademark] B1358/100 manufactured by Evonik Degussa GmbH.
The crosslinking agent may be a compound having at least two vinyl ether groups. Examples of the compound include bis(4-(vinyloxymethyl)cyclohexylmethyl)glutarate, tri(ethylene glycol) divinyl ether, adipic acid divinyl ester, diethylene glycol divinyl ether, 1,2,4-tris(4-vinyloxibutyl) trimellitate, 1,3,5-tris(4-vinyloxybutyl)trimellitate, bis(4-(vinyloxy)butyl)terephthalate, bis(4-(vinyloxy)butyl)isophthalate, ethylene glycol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, tetraethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trimethylolethane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, and cyclohexanedimethanol divinyl ether.
The crosslinking agent may also be a highly heat-resistant crosslinking agent. The highly heat-resistant crosslinking agent is preferably a compound containing a crosslink-forming substituent with an aromatic ring (for example, benzene or naphthalene ring) in the molecule.
Examples of the compound include compounds having the partial substructure of the following formula (4) and polymers or oligomers having the repeating units of the following formula (5).
The above R11, R12, R13 and R14 are hydrogen atoms or an alkyl group having 1 to 10 carbon atoms, and the above examples may apply to the alkyl group. n1 is an integer of from 1 to 4, n2 is an integer of from 1 to (5−n1), and (n1+n2) represents an integer of from 2 to 5. n3 is an integer of from 1 to 4, n4 is from 0 to (4−n3), and (n3+n4) represents an integer of from 1 to 4. The number of repeating unit structures of the oligomers and polymers may range from 2 to 100 or 2 to 50.
Examples of the compounds, polymers and oligomers of formulas (4) and (5) are listed below.
The above compounds are available as products of Asahi Yukizai Corporation and Honshu Chemical Industry Co., Ltd. For example, of the above crosslinking agents, the compound of formula (4-23) is available from Honshu Chemical Industry Co., Ltd. under the trade name TMOM-BP, and the compound of formula (4-24) is available from Asahi Yukizai Corporation under the trade name TM-BIP-A.
The amount of the crosslinking agent used varies depending on the coating solvent used, substrate used, required solution viscosity, required film shape, and other factors, and is 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.5% by mass or more, or 1.0% by mass or more, and 80% by mass or less, 50% by mass or less, 40% by mass or less, 20% by mass or less, or 10% by mass or less of the total solid content. These crosslinking agent may cause crosslinking reaction by self-condensation, but can cause crosslinking reaction with the crosslinking substituents, if any, present in the above polymer of the present invention.
The crosslinking agents may be added each alone or in combination of two or more thereof.
(Acid and/or Salt thereof and/or Acid Generator)
The resist underlayer film-forming composition of the present invention may include an acid and/or a salt thereof and/or an acid generator.
Examples of the acid include p-toluenesulfonic acid, trifluoromethanesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzene sulfonic acid, benzenedisulfonic acid, 1-naphthalene sulfonic acid, carboxylic acid compounds such as citric acid, benzoic acid, hydroxybenzoic acid, naphthalene carboxylic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.
The salt may be a salt of the above-mentioned acid. Although the salt is not limited, but preferable examples thereof include ammonia derivative salts such as trimethylamine and triethylamine salts, pyridine derivative salts, and morpholine derivative salts.
The acid and/or the salt thereof may be used each alone or in combination of two or more thereof. The amount of the compound is usually within the range of from 0.0001 to 20% by mass, preferably from 0.0005 to 10% by mass, and even more preferably from 0.01 to 5% by mass of the total solid content.
Examples of the acid generator include thermal acid generators and photoacid generators.
Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE [registered trademark] CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG-2689, TAG-2700 (manufactured by King Industries, Inc.), SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), quaternary ammonium salts of trifluoroacetic acid, and alkyl esters of organic sulfonic acids.
The photoacid generator generates an acid when the resist is exposed. This allows adjustment of the acidity of the underlayer film. This is one method for matching the acidity of the underlayer film with the upper layer resist. In addition, the pattern shape of the resist formed on the upper layer can be adjusted by adjusting the acidity of the underlayer film.
Examples of the photoacid generator included in the resist underlayer film-forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.
Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoronormalbutanesulfonate, diphenyliodonium perfluoronormaloctanesulfonate, diphenyliodonium camphor sulfonate, bis(4-tert-butylphenyl)iodonium camphor sulfonate, and bis(4-tert-butylphenyl)iodonium, and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoronormalbutanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.
Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy) succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.
Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.
The acid generator may be used each alone or in combination of two or more thereof.
When an acid generator is used, its ratio is within the range of from 0.01 to 10 parts by mass, from 0.1 to 8 parts by mass, or from 0.5 to 5 parts by mass with respect to 100 parts by mass of the solid content of the resist underlayer film-forming composition.
(Surfactant)
The resist underlayer film-forming composition of the present invention may contain a surfactant to prevent pinholes and striations, and to further improve the application property to uneven surfaces. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl allyl ethers such as polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenol ethers; polyoxyethylene/polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorosurfactants such as F-Top [registered trademark] EF301, EF303, and EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Megaface [registered trademark] F171, F173, R-30, R-30-N, R-40, and R-40-LM (manufactured by DIC Corporation), Fluorad [registered trademark] FC430 and FC431 (manufactured by Sumitomo 3M Limited.), and Asahi Guard [registered trademark] AG710, Surflon [registered trademark] S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The surfactants may be added each alone or in combination of two or more thereof. The content ratio of the surfactant is, for example, within the range of from 0.01 to 5% by mass of the solid content of the resist underlayer film-forming composition of the present invention, excluding the solvent mentioned below.
The resist underlayer film-forming composition of the present invention may further include additives such as light absorbing agents, rheology modifiers, and adhesion aids. Rheology modifiers are effective in improving the flowability of the underlayer film-forming composition. Adhesion aids are effective in improving adhesion between the semiconductor substrate or resist and the underlayer film.
(Light Absorbing Agent)
Preferable examples of the light absorbing agent include commercially available absorbents listed in “Technology and Market of Industrial Dyes” (CMC Publishing Co., Ltd.) and “Dye Handbook” (edited by The Society of Synthetic Organic Chemistry, Japan), such as C.I. Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 30 96; C.I. Fluorescent Brightening Agent 112, 135, and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; C.I. Pigment Green 10; and C.I. Pigment Brown 2. The blending amount of the light absorbing agent is usually 10% by mass or less, preferably 5% by mass or less of the total solid content of the resist underlayer film-forming composition.
(Rheology Modifier)
The rheology modifier is added mainly to improve the flowability of the resist underlayer film-forming composition, especially in the baking step, to improve the uniformity of the resist underlayer film thickness and the filling property of the resist underlayer film-forming composition into the hole. Specific examples thereof include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as dinormal butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. The blending amount of the rheology modifier is usually less than 30% by mass of the total solid content of the resist underlayer film-forming composition.
(Adhesion Aid)
The adhesion aid is added mainly to improve the adhesion between the substrate or resist and the resist underlayer film-forming composition, especially to prevent the resist from peeling off during development. Specific examples thereof include chlorosilanes such as trimethylchlorosilane, dimethylmethylol chlorosilane, methyldiphenylchlorosilane, and chloromethyl dimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylmethylol ethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane;
silazanes such as hexamethyldisilazane, N,N′-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; silanes such as methylol trichlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercapto-benzimidazole, 2-mercapto-benzothiazole, 2-mercapto-benzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; urea such as 1,1-dimethylurea and 1,3-dimethylurea; and thiourea compounds. The blending amount of the adhesion aid is usually less than 5% by mass, preferably less than 2% by mass of the total solid content of the resist underlayer film-forming composition.
The solid content of the resist underlayer film-forming composition of the present invention is usually within the range of from 0.1 to 70% by mass, preferably from 0.1 to 60% by mass. The solid content is the content ratio of all components in the resist underlayer film-forming composition minus the solvent. The ratio of the above polymer in the solid content is, in the order of increasing preference, within the range of from 1 to 100% by mass, from 1 to 99.9% by mass, from 50 to 99.9% by mass, from 50 to 95% by mass, and from 50 to 90% by mass.
One of the measures for evaluating whether the resist underlayer film-forming composition is in a uniform solution state is to observe its passage through a specific microfilter, and the resist underlayer film-forming composition of the present invention passes through a microfilter with a pore diameter of 0.1 μm and exhibits a uniform solution state.
Examples of the microfilter material include fluorine-based resins such as PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), PE (polyethylene), UPE (ultra high molecular weight polyethylene), PP (polypropylene), PSF (polysulfone), PES (polyethersulfone), and nylon. Of these, PTFE (polytetrafluoroethylene) is preferable.
<Resist Underlayer Film>
The resist underlayer film may be formed as follows using the resist underlayer film-forming composition of the present invention.
The resist underlayer film is formed by coating the resist underlayer film-forming composition of the present invention on a substrate used for producing semiconductor devices (for example, silicon wafer, silicon dioxide (SiO2), silicon nitride (SiN), silicon oxide nitride (SiON), titanium nitride (TiN), tungsten (W), glass, ITO, and polyimide substrates, and substrates coated with low-k materials) by an appropriate coating method such as a spinner or a coater followed by baking using a heating means such as a hot plate. The baking conditions are appropriately selected from a baking temperature of from 80° C. to 600° C. and a baking time of from 0.3 to 60 minutes. The baking temperature is preferably from 150° C. to 350° C. and the baking time is preferably from 0.5 to 2 minutes. The atmosphere gas during baking may be air or an inert gas such as nitrogen or argon. The thickness of the underlayer film formed is, for example, within the range of from 10 to 1000 nm, from 20 to 500 nm, from 30 to 400 nm, or from 50 to 300 nm. The substrate may be a quartz substrate, in which case a replica of a quartz imprint mold (mold replica) can be fabricated.
In addition, an inorganic resist underlayer film (hard mask) may also be formed on the organic resist underlayer film of the present invention. It may be formed, for example, by spin-coating the composition for forming a silicon-containing resist underlayer film (inorganic resist underlayer film) described in WO 2009/104552 A1, or by forming a Si-based inorganic material film by a CVD method. The hard mask in the present invention includes both a silicon hard mask and a CVD film.
In addition, an adhesion layer and/or a silicone layer containing 99% by mass or less or 50% by mass or less Si may be formed on the resist underlayer film of the present invention by coating or vapor deposition. It may be formed, for example, by spin-coating the adhesion layer described in JP 2013-202982 A and Japanese Patent No. 5827180, or the composition for forming silicon-containing resist underlayer film (inorganic resist underlayer film) described in WO 2009/104552 A1, or by forming a Si-based inorganic material film by a CVD method.
In addition, by applying the resist underlayer film-forming composition of the present invention onto a semiconductor substrate having a stepped portion and a non-stepped portion (the so-called stepped substrate) followed by baking, a resist underlayer film may be formed with a smaller step between the stepped portion and non-stepped portion.
<Method for Producing Semiconductor Device>
The method for producing a semiconductor device according to the present invention comprises the steps of:
forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition of the present invention;
forming a resist film on the formed resist underlayer film;
forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development;
etching and patterning the resist underlayer film through the formed resist pattern; and
processing the semiconductor substrate through the patterned resist underlayer film.
The method for producing a semiconductor device according to the present invention comprises the steps of:
forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to the present invention;
forming a hard mask on the formed resist underlayer film;
forming a resist film on the formed hard mask;
forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development;
etching the hard mask through the formed resist pattern; etching the resist underlayer film through the etched hard mask; and removing the hard mask.
The method preferably further comprises the steps of:
forming a vapor-deposited film (spacer) on the underlayer film from which the hard mask has been removed;
processing the formed vapor-deposited film (spacer) by etching;
removing the underlayer film; and
processing the semiconductor substrate with the spacer.
The semiconductor substrate may be a stepped substrate.
The steps of forming a resist underlayer film using the resist underlayer film-forming composition of the present invention are as described above.
A resist film, for example, a layer of photoresist, is then formed on the resist underlayer film. The formation of the photoresist layer may be performed by a well-known method, that is, by applying a photoresist composition solution to the underlayer film and baking it. The film thickness of the photoresist is, for example, within the range of from 50 to 10,000 nm, from 100 to 2000 nm, or from 200 to 1000 nm.
The photoresist formed on the resist underlayer film is not particularly limited as long as it is sensitive to a light used for exposure. Both negative and positive photoresists may be used. Examples thereof include positive photoresists including a novolac resin and 1,2-naphthoquinone diazide sulfonate; chemically amplified photoresists including a binder having a group that is decomposed by acid to increase the alkali dissolution rate and a photoacid generator; chemically amplified photoresists including a low molecular weight compound that is decomposed by acid to increase the alkali dissolution rate of photoresist, an alkaline soluble binder, and a photoacid generator; and chemically amplified photoresists including a binder having a group that is decomposed by acid to increase the alkali dissolution rate, a low molecular weight compound that is decomposed by acid to increase the alkali dissolution rate of the photoresist, and a photoacid generator. Examples thereof include APEX-E (trade name) manufactured by Shipley, PAR 710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and SEPR 430 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. Other examples include fluorinated polymer-based photoresists described in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).
Next, a resist pattern is formed by photo or electron beam irradiation and development. First, exposure is performed through a predetermined mask. Near ultraviolet, far ultraviolet, or extreme ultraviolet (for example, EUV (13.5 nm wavelength)) light is used for exposure. Specifically, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), an F2 excimer laser (wavelength: 157 nm), and the like may be used. Of these, ArF excimer laser (wavelength: 193 nm) and EUV (wavelength: 13.5 nm) are preferable. After the exposure, post exposure bake may be performed as necessary. The post exposure bake is performed under conditions appropriately selected from a heating temperature of from 70° C. to 150° C. and a heating time of from 0.3 to 10 minutes.
In the present invention, a resist for electron beam lithography may be used instead of a photoresist. The electron beam resist may be either negative or positive type. Examples thereof include chemically amplified resists including an acid generator and a binder having a group that is decomposed by acid to change the alkali dissolution rate; chemically amplified resists including an alkaline soluble binder, an acid generator, and a low molecular weight compound that is decomposed by acid to change the alkali dissolution rate of the resist; chemically amplified resists including an acid generator, a binder having a group that is decomposed by acid to change the alkali dissolution rate of the resist, and a low molecular weight compound that is decomposed by acid to change the alkali dissolution rate of the resist; non-chemically amplified resists including a binder having a group that is decomposed by an electron beam to change the alkali dissolution rate; and non-chemically amplified resists including a binder having a site that is cleaved by an electron beam to change the alkali dissolution rate. Also in the case these electron beam resists are used, resist patterns can be formed in the same manner as in using a photoresist with an electron beam as the irradiation source.
Alternatively, for the purpose of maintaining and improving high resolution and the depth of field, a method in which a substrate with a resist film formed thereon is immersed in a liquid medium for exposure may be adopted. At this time, the resist underlayer film is also required to be resistant to the liquid medium used, and a resist underlayer film that meets this requirement can be formed using the resist underlayer film-forming composition of the present invention.
Next, development is performed with a developing solution. As a result, when a positive photoresist is used, for example, the photoresist in the exposed area is removed, and a pattern of the photoresist is formed.
Examples of the developing solution include alkaline aqueous solutions such as aqueous solutions of alkali metal hydroxides such as potassium oxide and sodium hydroxide, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine. In addition, surfactants and other agents may be added to these developing solutions. The conditions for development are selected from a temperature of 5 to 50° C. and a time of 10 to 600 seconds.
Then, the inorganic underlayer film (intermediate layer) is removed using the pattern of the photoresist (upper layer) formed in this manner as a protective film, and then the organic underlayer film (underlayer) is removed using the film including the patterned photoresist and the inorganic underlayer film (intermediate layer) as a protective film. Finally, the semiconductor substrate is processed using the patterned inorganic underlayer film (intermediate layer) and organic underlayer film (underlayer) as protective films.
First, the inorganic underlayer film (intermediate layer) in the area where the photoresist has been removed is removed by dry etching to expose the semiconductor substrate. Dry etching of the inorganic underlayer film may be performed using a gas such as tetrafluoromethane (CF4), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, chlorine trifluoride, chlorine, trichloroborane, or dichloroborane. Dry etching of the inorganic underlayer film is preferably performed using a halogen-based gas, more preferably a fluorine-based gas. Examples of the fluorine-based gas include tetrafluoromethane (CF4), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, and difluoromethane (CH2F2).
Thereafter, the organic underlayer film is removed using the film including the patterned photoresist and the inorganic underlayer film as a protective film. The removal of the organic underlayer film (underlayer) is preferably performed by dry etching using an oxygen-based gas. This is because the inorganic underlayer film containing a large amount of silicon atoms is difficult to remove by dry etching using an oxygen-based gas.
In some cases, wet etching treatment is used to simplify the process and reduce damage to the processed substrate. The resist underlayer film-forming composition of the present invention allows to form a resist underlayer film that exhibits sufficient resistance to the chemical solutions used in wet etching.
Finally, the semiconductor substrate is processed. Processing of the semiconductor substrate is preferably performed by dry etching using a fluorine-based gas.
Examples of the fluorine-based gas include tetrafluoromethane (CF4), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, and difluoromethane (CH2F2).
In addition, an organic antireflection film may be formed on the upper layer of the resist underlayer film before the photoresist is formed. The antireflection film composition used in this process is not particularly limited, and may be selected from those conventionally used in the lithography process. The antireflection film may be formed by the conventional methods, such as application with a spinner or coater and baking.
In the present invention, after an organic underlayer film is formed on a substrate, an inorganic underlayer film is formed thereon, and a photoresist may be further coated thereon. This narrows the pattern width of the photoresist and prevents pattern collapse, allowing the substrate to be processed by selecting an appropriate etching gas, even when the photoresist is thinly coated. For example, it is possible to process the resist underlayer film using a fluorine-based gas having a sufficiently fast etching rate for a photoresist as an etching gas, and it is possible to process the substrate using a fluorine-based gas having a sufficiently fast etching rate for an inorganic underlayer film, and it is also possible to process the substrate using an oxygen-based gas having a sufficiently fast etching rate for an organic underlayer film.
The resist underlayer film formed from the resist underlayer film-forming composition may also absorb a light depending on the wavelength of the light used in the lithography process. In such a case, it can function as an antireflection film with the effect of preventing reflected light from the substrate. Furthermore, the underlayer film formed with the resist underlayer film-forming composition of the present invention can also function as a hard mask. The underlayer film of the present invention is also useful as, for example, a layer to prevent interaction between the substrate and photoresist, a layer that has the function of preventing materials used in the photoresist or substances generated during exposure of the photoresist from having an adverse effect on the substrate, a layer that has the function of preventing diffusion of substances generated from the substrate to the upper layer photoresist during heating and baking, or a barrier layer to reduce the poisoning effect of the photoresist layer by the dielectric layer of the semiconductor substrate.
The underlayer film formed from the resist underlayer film-forming composition may be applied to a substrate with via holes used in the dual damascene process and used as an embedding material that can fill the holes without gaps. It may also be used as a planarization material to flatten the surface of an uneven semiconductor substrate.
The present invention is described in more detail below with reference to examples and others, but the present invention is not limited in any way by the following examples.
The apparatus and others used to measure the weight average molecular weight of the compounds obtained in the synthesis examples are described below.
Apparatus: HLC-8320 GPC manufactured by Tosoh Corporation
GPC column: TSKgel Super-Multipore HZ-N (two columns)
Column temperature: 40° C.
Flow rate: 0.35 mL/min
Eluent: THF
Standard sample: polystyrene
35.00 g of diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 21.97 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.60 g of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as MSA), and 230.25 g of propylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA) were placed in a flask. The mixture was then heated to 115° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-1). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,100.
35.00 g of carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 32.72 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 2.01 g of MSA, and 162.71 g of PGMEA were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-2). The weight average molecular weight Mw measured by GPC measured in terms of polystyrene by GPC was about 2,600.
50.00 g of 2-phenylindole (manufactured by Tokyo Chemical Industry Co., Ltd.), 40.41 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 4.97 g of MSA, and 143.07 g of PGMEA were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-3). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 1,700.
45.00 g of 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.), 29.79 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 5.40 g of MSA, and 187.11 g of PGMEA were placed in a flask. The mixture was then heated to reflux under nitrogen and allowed to react for about 1.5 hours. After the termination of the reaction, the product was diluted with propylene glycol monomethyl ether (hereafter referred to as PGME), precipitated with water/methanol, and dried to obtain a resin (1-4). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,600.
60.00 g of 9,9-bis (4-hydroxyphenyl) fluorene (manufactured by Tokyo Chemical Industry Co., Ltd.), 18.17 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 3.29 g of MSA, and 99.56 g of PGMEA were placed in a flask. The mixture was then heated to reflux under nitrogen and allowed to react for about 4 hours. After the termination of the reaction, the product was diluted with PGMEA, precipitated with water/methanol, and dried to obtain a resin (1-5). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,100.
70.00 g of 2,2-biphenol (manufactured by Tokyo Chemical Industry Co., Ltd.), 29.36 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 43.28 g of 1-pyrenecarboxylaldehyde, 10.83 g of MSA, and 54.81 g of PGME were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for 24 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-6). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,000.
10.00 g of the resin obtained in Synthesis Example 1, 6.97 g of propargylic bromide (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as PBr), 2.17 g of tetrabutylammonium iodide (hereinafter referred to as TB AI), 21.53 g of tetrahydrofuran (hereinafter referred to as THF), and 7.18 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with methyl isobutyl ketone (hereinafter referred to as MIBK) and water, and the organic layer was concentrated, redissolved in
PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-7). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,100.
10.00 g of the resin obtained in Synthesis Example 2, 6.89 g of PBr, 3.21 g of TBAI, 22.61 g of THF, and 7.54 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 18 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-8). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 3,000.
15.00 g of the resin obtained in Synthesis Example 3, 10.52 g of PBr, 4.90 g of TBAI, 34.21 g of THF, and 11.40 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-9). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 1,900.
15.00 g of the resin obtained in Synthesis Example 4, 12.57 g of PBr, 5.85 g of tetrabutylammonium bromide (hereinafter referred to as TBAB), 37.60 g of THF, and 12.53 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 16 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-10). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,900.
15.00 g of the resin obtained in Synthesis Example 5, 13.57 g of PBr, 6.32 g of TBAB, 39.25 g of THF, and 13.08 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 16 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-11). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,600.
10.00 g of the resin obtained in Synthesis Example 6, 12.78 g of PBr, 5.86 g of TBAB, 21.48 g of THF, and 7.16 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-12).
The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,300.
10.00 g of the resin obtained in Synthesis Example 1, 10.99 g of α-chloro-p-xylene (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as CMX), 5.77 g of TBAI, 16.06 g of THF, and 10.71 g of a 25% aqueous sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and cyclohexanone (hereinafter referred to as CYH), and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-13). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,500.
10.00 g of the resin obtained in Synthesis Example 2, 9.91 g of benzyl bromide (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as BBr), 3.21 g of TBAI, 26.01 g of THF, and 8.67 g of a 25% aqueous sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 18 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and CYH, and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-14). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 2,800.
10.00 g of the resin obtained in Synthesis Example 6, 15.55 g of BBr, 4.40 g of TBAB, 22.46 g of THF, and 7.49 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and CYH, and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-15). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,000.
The resin obtained in Synthesis Example 7 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.48% compound solution. To 2.43 g of this resin solution, 0.12 g of PL-LI (manufactured by Midori Kagaku Co., Ltd.), 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 8.07 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 8 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.63% compound solution. To 2.54 g of this resin solution, 0.12 g of 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.96 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 9 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 22.47% compound solution. To 2.53 g of this resin solution, 0.11 g of PL-LI, 0.85 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 10 0.06 g of PGMEA containing 1% by mass of a surfactant, 11.49 g of PGMEA, and 4.95 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 10 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.21% compound solution. To 3.60 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 13.91 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 11 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 21.25% compound solution. To 3.25 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 14.26 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 12 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.44% compound solution. To 2.44 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGM containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 8.07 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 13 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.77% compound solution. To 2.40 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 3.53 of PGME, and 6.72 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 14 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 21.63% compound solution. To 2.19 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 2.53 of PGME, and 6.92 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 15 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.56% compound solution. To 2.42 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 2.53 of PGME, and 6.69 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 1 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.73% compound solution. To 2.53 g of this resin solution, 0.12 g of 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.98 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 2 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 17.08% compound solution. To 2.77 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.73 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 3 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 20.20% compound solution. To 2.41 g of this resin solution, 0.10 g of PL-LI, 0.73 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 0.91 g of PGMEA, 2.16 g of PGME, and 8.64 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 4 was dissolved in PGME, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.06% compound solution. To 3.83 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 7.17 g of PGMEA, and 13.24 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 5 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.44% compound solution. To 3.56 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 13.95 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
The resin obtained in Synthesis Example 6 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 29.80% compound solution. To 2.78 g of this resin solution, 0.21 g of PL-LI, 0.62 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.08 g of PGMEA containing 1% by mass of a surfactant, 7.73 g of PGMEA, and 3.58 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.
(Contact Angle Measurement)
Each of the polymer solutions used in Comparative Examples 1-6 and 1-9 was applied to a silicon wafer using a spin coater, and baked on a hot plate at 160° C. for 60 seconds to form a polymer film. Thereafter, the contact angle of the polymer to pure water was measured using a contact angle meter manufactured by Kyowa Interface Science Co., Ltd. The contact angle of the polymer used in each of the Examples was compared with that of the polymer used in the corresponding Comparative Example, respectively. The cases in which the contact angle of the polymer used in the Example was higher than that in the corresponding Comparative Example were indicated as “○”.
Comparing Comparative Example 1 with Example 1 and Example 7, Comparative Example 2 with Example 2 and Example 8, Comparative Example 3 with Example 3, Comparative Example 4 with Example 4, Comparative Example 5 with Example 5, and Comparative Example 6 with Example 6 and Example 9 revealed that the polymers used in Examples showed a higher contact angle than those used in Comparative Examples.
(Elution Test in Resist Solvent)
Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to a silicon wafer, respectively, using a spin coater, and baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film (film thickness: 65 nm). These resist underlayer films were immersed in a mixed solvent of PGME/PGMEA in a ratio of 7/3, which is a general-purpose thinner. The resist underlayer film was insoluble. And it was confirmed that the film had a sufficient curability.
(Application Property Test)
Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to a silicon wafer, respectively, using a spin coater, and baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film. Further thereon, a coating type silicon solution was applied and baked at 215° C. for 60 seconds to form a silicon film. Thereafter, the thickness of the film was measured. Then, a value was calculated according to “[Variation in film thickness (maximum film thickness—minimum film thickness)]/[Average film thickness]×100”. When this value is low, the application property can be judged to be good. The cases in which the application property of the Example is better than that of the corresponding Comparative Example were judged as
Comparing Comparative Example 1 with Example 1 and Example 7, Comparative Example 2 with Example 2 and Example 8, Comparative Example 3 with Example 3, Comparative Example 4 with Example 4, Comparative Example 5 with Example 5, Comparative Example 6 with Example 6 and Example 9 revealed that Examples exhibited better application properties than Comparative Examples. This is due to the hydrophobic nature of the polymer, which improved the application property.
(Chemical Solution Resistance Test)
Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to SiON, respectively, using a spin coater. The coating was baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film (film thickness: 65 nm thick). Thereon were formed a silicon hard mask layer (film thickness: 20 nm) and a resist layer (AR2772JN-14, manufactured by JSR Corporation, film thickness: 120 nm). The product was exposed at a wavelength of 193 nm using a mask followed by development to obtain a resist pattern. Then, the resist pattern was dry etched using fluorine-based gas and oxygen-based gas using an etching apparatus manufactured by Lam Research Co., Ltd., and the resulting resist pattern was transferred to the resist underlayer film. By the confirmation with CG-4100 manufactured by Hitachi Technology Co., Ltd., the pattern shape was confirmed to have provided a 50 nm line pattern.
The pattern wafer obtained here was cut and immersed in SARC-410 (manufactured by Nihon Entegris G.K.) heated to 30° C. After immersion, the wafer was taken out, rinsed with water, and dried. The dried wafer was observed with a scanning electron microscope (Regulus 8240) to check whether the pattern shape formed by the resist underlayer film was not deteriorated or whether the pattern was not collapsed. When the pattern shape is not deteriorated and is not suffered from collapse, its resistance to the chemical solution is high. The cases in which the polymer caused neither pattern shape deterioration nor pattern collapse even after immersion in the chemical solution for a longer period of time than the polymer of a similar structure in Comparative Example were judged as “○”.
In the cases of baking at 240° C., as seen in comparisons between Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, Comparative Example 3 and Example 3, Comparative Example 4 and Example 4, Comparative Example 5 and Example 5, and Comparative Example 6 and Example 6, modification of amino and hydroxyl groups made it possible to improve the chemical solution resistance to alkaline chemical solutions. Similarly, the chemical solution resistance was improved in the cases of high-temperature baking at 350° C. Therefore, they are the materials that can be applied to the processes using chemical solutions.
The present invention provides a novel resist underlayer film-forming composition that can meet such requirements: providing a hydrophobic underlayer film that exhibits a high contact angle with pure water and a high adhesion to the upper layer film, and robust to peeling off, as well as having a good application property, while also exhibiting other good properties such as sufficient resistance to the chemical solutions used for the resist underlayer film.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-132897 | Aug 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/028713 | 8/3/2021 | WO |
