TWI708124B - Pattern forming material, pattern forming composition, pattern forming method, and manufacturing method of semiconductor device - Google Patents

Abstract

According to one embodiment, an organic film is formed on the processed film on a substrate with a processed film and patterned using a pattern forming material. After patterning, a composite film formed by impregnating a metal compound in the organic film is used as a mask. The mask pattern is the pattern forming material used when processing the film to be processed, and it contains a polymer containing a first monomer unit having a non-shared electron pair and an aromatic ring in the side chain.

Description

Pattern forming material, pattern forming composition, pattern forming method, and manufacturing method of semiconductor device

The embodiments of the plural forms described herein generally relate to pattern forming materials, pattern forming compositions, pattern forming methods, and manufacturing methods of semiconductor devices.

In the manufacturing process of semiconductor devices, expectations for a technology for forming patterns with relatively high length and width have become higher. The mask pattern used in these steps requires high etching resistance due to long exposure to etching gas.

The embodiment of the present invention provides a pattern forming material capable of producing a mask pattern formed of a metal-containing organic film with high etching resistance, a pattern forming composition containing the pattern forming material, a pattern forming method, and Manufacturing method of semiconductor device.

The pattern forming material of the embodiment is formed on the processed film on the substrate with the processed film. After the pattern forming material is used to form an organic film and patterned, the composite film formed by impregnating the metal compound in the organic film As the mask pattern, the pattern forming material used when processing the film to be processed, and which contains a polymer containing the first monomer unit represented by the following general formula (1).

However, in the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group that may contain an oxygen atom. At least one of these is a hydrocarbon group, and the total carbon number of these is 1-13 , These can be combined to form a ring. R ⁴ is a hydrogen atom or a methyl group. R ⁵ is a single bond or a hydrocarbon group with 1 to 20 carbon atoms that may contain oxygen, nitrogen, or sulfur atoms between carbon and carbon atoms or at the end of the bond. The hydrogen atom may be substituted by a halogen atom.

According to the above configuration, it is possible to provide a pattern forming material capable of producing a mask pattern made of a metal-containing organic film with high etching resistance, a pattern forming composition including the pattern forming material, a pattern forming method, and Manufacturing method of semiconductor device.

The present invention will be described in detail below with reference to the drawings. In addition, the present invention is not limited by the following embodiments. In addition, the constituent elements in the following embodiments include those that are easily thought of by those familiar with the art or those that are substantially the same.

A polymer is a polymer formed by the polymerization of monomers, which is composed of repeating units derived from monomers. In this specification, the repeating units constituting the polymer are called monomer units. A monomer unit is a unit derived from a monomer, and the so-called constitutional single system of a monomer unit refers to a monomer that forms the monomer unit by polymerization. In this specification, the monomer unit represented by the general formula (1) is also referred to as the monomer unit (1). The monomer units and compounds represented by other general formulas or chemical structural formulas are also represented by the symbols of general formulas or chemical structural formulas.

In view of the above-mentioned problems, the inventors found that after forming an organic film using a pattern forming material containing a specific polymer and patterning, a composite film formed by impregnating a metal compound in the organic film as a mask pattern can be obtained Mask pattern with high etching resistance. Impregnation of metal compounds in organic films is called "metallized." Specifically, metallization can be performed by bonding a metal compound to the organic film having a bonding site of the metal compound. The metal compound may also be subjected to post-treatment such as oxidation after bonding. The following describes the pattern forming material containing the specific polymer according to the embodiment of the present invention.

[Pattern Forming Material] The pattern forming material of the embodiment (hereinafter referred to as "this pattern forming material") contains a polymer (hereinafter also referred to as polymer X) containing a first monomer unit represented by the following general formula (1).

However, in the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group that may contain an oxygen atom. At least one of these is a hydrocarbon group, and the total carbon number of these is 1-13 , These can be combined to form a ring. R ⁴ is a hydrogen atom or a methyl group. R ⁵ is a single bond or a hydrocarbon group with 1 to 20 carbon atoms that may contain oxygen, nitrogen, or sulfur atoms between carbon and carbon atoms or at the end of the bond. The hydrogen atom may be substituted by a halogen atom.

The monomer unit (1) has a structure of an ester having a carboxyl group at the end of the side chain. The carbon atom (C of the group represented by CR ¹ R ² R ³ in the general formula (1)) bonded to the adjacent oxygen atom of the carbonyl group in the ester is a first-order carbon, a second-order carbon or a third-order carbon. By making the monomer unit (1) have such side chains, as follows, a composite film with a metal compound strongly bonded to the organic film obtained from the pattern forming material can be obtained.

This pattern forming material is used to form an organic film on a processed film on a substrate with a processed film. This pattern forming material is contained, for example, together with an organic solvent in the pattern forming composition of the embodiment described later, and the composition is applied to the processed film to form an organic film.

The organic film can be formed by the pattern forming material itself, or can be formed by reacting components contained in the pattern forming material. After the organic film is patterned, it becomes a composite film in which a metal compound is bonded to the first monomer unit of the organic film. Furthermore, the composite film is used as a mask pattern to process the film to be processed.

In the polymer X, the reaction system of bonding a metal compound to the monomer unit (1) of the first monomer unit is, for example, the reaction shown in the following reaction formula (F). The reaction shown in the reaction formula (F) is a reaction example in the case of using trimethylaluminum (TMA) as a metal compound. At least one of R ¹ , R ² and R ^{3 in} the monomer unit (1) is a hydrocarbon group. In the reaction formula (F), R ¹ of the monomer unit (1) is a hydrocarbon group, and R ² and R ³ are hydrogen atoms or a hydrocarbon group, indicating the bonding of TMA to the monomer unit (1). n represents the repeating number of monomer unit (1) in polymer X.

When TMA reacts with the monomer unit (1) in the polymer X, the Al of TMA is coordinated to the non-shared electron pair of =0 of the carbonyl group of the monomer unit (1). At this time, it is presumed that the ester is bonded to the side chain terminal of the monomer unit (1), which weakens the bonding force with the hydrocarbon group (-CR ¹ R ² R ³ ) of the first, second or third level. As a result, -CR ¹ R ² R ³ detaches from the monomer unit (1) and becomes a monomer unit represented by general formula (1') in which Al of TMA is bonded to two oxygen atoms derived from an ester bond.

The separated hydrocarbon group is recovered as R ^1' =CR ² R ³ . Here, R ^{1 'R 1} removed from the system after the group of a hydrogen atom. Further, the reaction of formula (F) for convenience sake, referred to as a leaving group, ^{R 1 '= CR 2 R 3} , but may also have ^{R 1 C = R 2' R} 3 (R 2 ' R ² removed from the system after one of the hydrogen atoms) or R ¹ C = R ³ where ^{'R 2} (R ^3' R ³ from the line of the group removed a hydrogen atom) of. In this way, hydrogen is removed from the leaving group to become an alkenyl group and leave. It is presumed that the hydrogen removed from the leaving group is replaced by the methyl group of TMA and is removed from TMA as methane.

In the polymer X, when the monomer unit (1) of the first monomer unit is bonded to the metal compound, it is considered that the detached hydrocarbon group and the sequence of the above reaction formula (F) additionally become the reaction shown in the following reaction formula (G). Can also be considered as a reaction formula (G) shown for convenience as R ¹ C ⁺ R ² R ³ monomeric units derived from (1) is disengaged, and then departing from the TMA (CH ₃₎ ^- bond, also It becomes R ¹ C(CH ₃ )R ² R ^{3 and the main} chain is separated.

The 1, 2, or 3 hydrocarbon group (-CR ¹ R ² R ³ ) that is ester-bonded at the side chain end of the monomer unit (1) to the carbonyl group of the monomer unit (1) does not adsorb metals such as TMA The situation of the compound is also separated by specific conditions. However, as shown in the reaction formula (F), when the carbonyl group of the monomer unit (1) is coordinated with a metal compound such as TMA, the hydrocarbyl group (-CR ¹ R ² R ³ ) can be removed more significantly than the above-mentioned specific conditions The mild conditions are reached. This is a phenomenon newly recognized by the present inventors. By this, it can be said that the metalization of the organic film formed using this pattern forming material can strongly bond the metal compound and is excellent in productivity.

In addition, the metallization in the embodiment is performed on an organic film formed using this pattern forming material. As described above, the organic film formed by using the pattern forming material may be formed by the pattern forming material itself, or it may be formed by reacting the components contained in the pattern forming material.

In this pattern forming material, the organic film formed of the polymer X preferably directly has a side chain structure of at least the monomer unit (1). Thereby, the composite film obtained by metalizing the organic film may have, for example, Al(CH ₃ ) _X (X is a number of 0-2, and the monomer unit (1') of the metal compound shown in the monomer unit (1') ) Is 2) the structure of 2 oxygen atoms strongly bonded to the monomer unit (1').

In addition, it can also be considered that the metal compound represented by the following general formula (3), for example, AlY (Y is an optional substituent such as a methyl group or a hydroxyl group) is held by two or more carbonyl groups. In this case, it is considered that, as shown in the general formula (1') in the above reaction formulas (F) and (G), a stronger bond is formed than that Al(CH ₃ ) _{X is} held by one carbonyl group. The number of coordinated carbonyl groups depends on the three-dimensional barrier between the central metal species and the surrounding polymer matrix.

In the monomer unit (1), C of -CR ¹ R ² R ³ is a first-grade carbon, a second-grade carbon, or a third-grade carbon. That is, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group, and at least one of these is a hydrocarbon group. In addition, when R ¹ , R ² and R ³ are hydrocarbon groups, these may also contain an oxygen atom. In the following description, when R ¹ , R ² and R ^{3 are} referred to as a hydrocarbon group, they include an oxygen-containing atom. When an oxygen atom is included, the oxygen atom may exist as a COC bond between two carbon atoms, or it may exist as a C=O bond on one carbon atom.

-When the C of CR ¹ R ² R ³ is a first-order carbon, any one of R ¹ , R ² and R ³ is a hydrocarbon group, and the remaining two are hydrogen atoms. -When the C of CR ¹ R ² R ³ is a secondary carbon, any 2 of R ¹ , R ² and R ³ is a hydrocarbon group, and the remaining 1 is a hydrogen atom. -When C of CR ¹ R ² R ³ is a tertiary carbon, R ¹ , R ² and R ³ are all hydrocarbon groups. In addition, the total carbon number of R ¹ , R ^2, and R ³ is 1 to 13, and the total carbon number of -CR ¹ R ² R ³ is 2 to 14.

Any two or three of R ¹ , R ² and R ³ may be combined with each other to form a ring. In addition, the formed ring may be a heterocyclic ring containing an oxygen atom. In addition, the combination of three of R ¹ , R ² and R ³ to form a ring means that -CR ¹ R ² R ³ represents, for example, a phenyl (-C ₆ H ₅ ) monovalent aromatic hydrocarbon group. When forming a ring, the carbon number of the ring is 3-14. The ring may be a polycyclic ring within the carbon number range, or the hydrogen atom bonded to the ring may be substituted with a hydrocarbon group that may have an oxygen atom. Examples of the hydrocarbon group as the substituent include an alkyl group, an aralkyl group, and an aryl group.

When the present inventors confirmed that the ester-bonded group at the end of the side chain in the general formula (1) is a monomer unit of CH ₃ , that is, outside the scope of the embodiment, for example, in metallization using TMA, the Al of TMA Although the non-shared electron pair of =O adsorbed on the carbonyl group, the CH ₃ group is detached from the end of the side chain. Therefore, these monomer units do not essentially adopt a structure in which the Al of TMA is bonded to the monomer unit (1') of 2 oxygen atoms derived from the ester bond.

In addition, the degree of metallization in the composite film can be confirmed by measuring the amount of metal contained in the metal compound in the composite film by X-ray photoelectron spectroscopy (XPS). In addition, the structure of the metal bond of the metal compound with two oxygen atoms derived from the ester bond of the monomer unit (1) in the organic film at the end of the side chain can be estimated by infrared spectroscopy (IR). That is, the absorption of the organic film before metallization is attenuated compared to the absorption of the carbonyl group derived from the ester. On the other hand, by detecting the new peak derived from the carbonium ion, it can be inferred It is a structure in which the metal of the metal compound is bonded to two oxygen atoms derived from the ester bond of the monomer unit (1) in the organic film at the end of the side chain.

Here, the stabilization energy of Al and O in a state where Al of TMA is coordinated to an unshared electron pair of =O of the carbonyl group is calculated to be 15kcal/mol. On the other hand, the Al of TMA in the monomer unit (1') is bonded to two oxygen atoms derived from an ester bond, and the bonding energy between Al and the two oxygen atoms is calculated to be 130 kcal/mol. In order to obtain such a strong bond, in the monomer unit (1), the C of -CR ¹ R ² R ³ is a first-level carbon, a second-level carbon, or a third-level carbon.

In addition, the hydrocarbons obtained by detaching from the side chain end of the monomer unit (1) during metallization, such as R ^1′ =CR ² R ³ in the reaction formula (F), are preferably removed from the composite membrane. Therefore, the total carbon number of R ¹ , R ² and R ³ is 1-10. The total carbon number of R ¹ , R ² and R ³ is preferably 1-9, more preferably 1-3.

When the composite film obtained by using this pattern forming material is used as the base film of the laminated mask structure described later, when the C of -CR ¹ R ² R ³ is grade 3 carbon, there is -CR ¹ R ² R ³ under relatively mild conditions. Detach from monomer unit (1). That is, when other layers are formed on the organic film like a multilayer mask structure, when the C of -CR ¹ R ² R ³ is grade 3 carbon, there will be -CR ¹ R ² R in the organic film when the layer is formed ³ The fear of leaving. When -CR ¹ R ² R ³ contained in the first monomer unit is decomposed to form a carboxylic acid, the formed carboxylic acid becomes an acid catalyst. If heat is applied to it, the surrounding ester bonds may be hydrolyzed. When C in CR ¹ R ² R ³ is grade 1 carbon or grade 2 carbon, compared with the case of grade 3 carbon, since -CR ¹ R ² R ³ is less likely to be detached, it may be applied during the production of the base film. In the temperature range, the C in -CR ¹ R ² R ³ is preferably a first-grade carbon or a second-grade carbon.

As -CR ¹ R ² R ³ Specifically, in the -CR ¹ R C ² R ³ of level 3 carbons, R ^1, R ² and R ³ are each independently exemplified by methyl, ethyl, propyl, butyl, Alkyl, pentyl, hexyl, heptyl, octyl, hydrocarbon groups with a total carbon number of 3-10. Among these, -CR ¹ R ² R ^{3 is} preferably a tertiary butyl group in which all of R ¹ , R ² and R ³ are methyl groups.

-When C of CR ¹ R ² R ³ is a secondary carbon, for example, if R ³ is a hydrogen atom, R ¹ and R ² are each independently methyl, ethyl, propyl, butyl, pentyl, and hexyl. , Heptyl, octyl, nonyl, hydrocarbon groups with a total carbon number of 2-10. Among them, as -CR ¹ R ² R ³ (but R ³ is H), it is preferable that R ¹ and R ² are both methyl isopropyl, and R ¹ and R ² are methyl and ethyl respectively. Dibutyl, R ¹ and R ^{2 are} each ethyl 3-pentyl, R ¹ and R ^{2 are} each propyl 4-heptyl, and R ¹ and R ^{2 are} each n-butyl 5-nonyl.

-When C of CR ¹ R ² R ³ is a first-order carbon, for example, if R ² and R ³ are hydrogen atoms, R ^{1 is} exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl , Octyl, nonyl, decyl, hydrocarbon groups with a total carbon number of 1-10. Among these, as -CR ¹ R ² R ³ (but R ² and R ³ are H), R ¹ is preferably an ethyl group with a methyl group, and R ¹ is a propyl group with an ethyl group. As -CR ¹ R ² R ³ (but R ² and R ³ is H) of R ^1, also preferred is benzyl.

In -CR ¹ R ² R ³ , any two or three of R ¹ , R ² and R ³ are bonded to each other to form a ring, for example, adamantyl, methyladamantyl, pyranyl, ring Hexyl, 4-tert-butylcyclohexyl, isobornyl, phenyl, naphthyl, anthracenyl, benzylphenyl, etc.

R ⁵ in the general formula (1) can be a single bond or a hydrocarbon group with 1 to 20 carbon atoms that can contain oxygen, nitrogen, and sulfur atoms between carbon and carbon atoms or at the end of the bond. The hydrogen atoms can be replaced by halogen atoms . Examples of halogen atoms are F, Cl, and Br. When R ⁵ is a single bond, the monomer unit (1) is a (meth)acrylate that constitutes the ester of a single-system (meth)acrylic acid. In addition, the general term for (meth)acrylic acrylic acid and methacrylic acid in this specification. (Meth)acrylate is a general term for acrylate and methacrylate.

When R ⁵ in the monomer unit (1) is a hydrocarbyl group, the hydrocarbyl group may be linear, branched or cyclic, or a combination of these. The ring may be an alicyclic ring or an aromatic ring. When it is an aromatic ring, it is preferable from the viewpoint of the etching resistance of the resulting composite film. The carbon number of R ⁵ is preferably 1-10 when it does not have a ring, and preferably 6-18 when it has a ring. When R ⁵ is a hydrocarbon group, it may contain an oxygen atom, a nitrogen atom, or a sulfur atom between carbon and carbon atoms or at the end of the bond, and the hydrogen atom may be substituted by a halogen atom. R ^{5 is} preferably a hydrocarbon group having no hetero atom. Examples of the case where R ⁵ is a hydrocarbon group having no hetero atom include 1,4-phenylene, 1,4-naphthylene, 1,4-anthrylene, and the like.

More specific examples of the constituent monomers of the monomer unit (1) are the monomers shown in Table 1 below. In Table ^1, R 1 ~ R ⁵ correspond to R of formula (1) of ¹ ~ R ^5. When the columns of R ¹ , R ^2, and R ^{3 are} combined into one display, the column indicates the basis as -CR ¹ R ² R ³ . In addition, in Table 1, "1,4-Ph" means 1,4-phenylene, "Ph" means phenyl, "Np" means naphthyl, and "An" means anthracenyl.

In Table 1, M-1 and M-6 are isopropyl methacrylate and isopropyl acrylate, respectively. M-2 and M-7 are n-butyl methacrylate and n-butyl acrylate, respectively. M-3 and M-8 are the second butyl methacrylate and the second butyl acrylate, respectively. M-4 and M-9 are isobutyl methacrylate and isobutyl acrylate, respectively. M-5 and M-10 are the second amyl methacrylate and the second amyl acrylate, respectively. M-11 is isopropyl 4-vinylbenzoate. M-12 is tert-butyl 4-vinylbenzoate. M-13 is the second butyl 4-vinylbenzoate. M-14 is isobutyl 4-vinylbenzoate. M-15 is the second pentyl 4-vinylbenzoate. M-16 and M-17 are phenyl methacrylate and phenyl acrylate, respectively. M-18 and M-19 are naphthyl methacrylate and naphthyl acrylate, respectively. M-20 and M-21 are anthracene methacrylate and anthracene acrylate, respectively. M-22 and M-23 are benzyl methacrylate and benzyl acrylate, respectively. M-24 and M-25 are benzylphenyl methacrylate and benzylphenyl acrylate, respectively.

As a constituent monomer of the first monomer unit, among these, monomers M-11-25 are preferred. Hereinafter, the monomer unit based on the monomer M-1 is referred to as the monomer unit M-1. Hereinafter, other monomers and monomer units are also described in the same way.

The polymer X may contain one type of first monomer unit, or two or more types. The polymer X may be composed of only the first monomer unit, or may be a copolymer of the first monomer unit and a monomer unit other than the first monomer unit. The ratio of the first monomer unit in the polymer X, relative to the total monomer units of the polymer X, is preferably 50 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% the above.

By making the polymer X have the first monomer unit, it is possible to have both the excellent metallization characteristics of the organic film obtained from the pattern forming material containing it and the high etching resistance of the resulting mask pattern. From the viewpoint of such metallization properties and etching resistance, the ratio of the first monomer unit in the polymer X is preferably 50 mol% or more, and it is particularly preferably 100 mol when other characteristics as described later are not considered. %.

The production of polymer X is carried out by common methods such as bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc., using the constituent monomers of monomer units. After polymerization, it is dissolved in a solvent. From the viewpoint of eliminating impurities such as emulsifiers and moisture, solution polymerization is preferred. When the polymer X is synthesized by solution polymerization, a specific monomer is usually dissolved in a polymerization solvent, and polymerization is carried out in the presence of a polymerization initiator. The monomer used in the production of the polymer X includes the constituent monomer of the first monomer unit. As described later, when the polymer X contains monomer units other than the first monomer unit, the constituent monomers of all the monomer units constituting the polymer X are used in the polymerization. The polymerization conditions such as the amount of polymerization solvent, polymerization temperature, and polymerization time are appropriately selected according to the type of monomers and the molecular weight of the synthesized polymer.

The weight average molecular weight (Mw) of the polymer X is preferably 1,000 to 1,000,000 [g/mol] (hereinafter sometimes omitted units), more preferably 2,000 to 1,000,000, particularly preferably 2,000 to 100,000. The molecular weight (Mw) of polymer X can be determined by gel permeation chromatography (GPC).

In addition, the above-mentioned metal compound bonded to the organic film can also be used as a mask pattern after proper processing. For example, in the case of Al(CH ₃ ) ₃ shown in the reaction formula (F), after bonding to the organic film, it may be oxidized to form aluminum hydroxide or aluminum oxide. The oxidation treatment is usually carried out with oxidants such as water, ozone, and oxygen plasma. In addition, the oxidation treatment can be carried out naturally by the moisture in the environment even without special operation.

In addition, Al(CH ₃ ) _{3 is taken} as an example of the metal compound bonded to the organic film. However, it may be an Al compound other than Al(CH ₃ ) ₃ , and the metal other than Al is, for example, Ti, V, Metal compounds such as W, Hf, Zr, Ta, Mo, etc. also obtain the same bond structure.

The composite film obtained by using this pattern forming material has high etching resistance because the metal compound is strongly bonded to the organic film. Examples of etching include reactive ion etching (RIE: Reactive Ion Etching), IBE, etc., and sufficient resistance can be achieved even for IBEs that require particularly high resistance. Here, in order to realize a processed shape with a high aspect ratio for the processed film, a multilayer mask structure is sometimes used in the mask pattern. When the composite film formed using this pattern forming material is used in a laminated mask structure, it is preferably used as a base film formed between the photoresist film and the processed film.

Conventionally, in a multilayer mask structure for the purpose of high etching resistance, a carbon deposition layer using a chemical vapor deposition (CVD: Chemical Vapor Deposition) method is used as a base film between the photoresist film and the film to be processed. The composite film formed using this pattern forming material has the function of replacing the carbon deposition layer of the CVD method, which is very high-cost, and has the advantages of cheap material and easy film formation.

(Polymer X) This pattern forming material contains a polymer containing the above-mentioned first monomer unit. In the polymer X, in order to impart the metallization characteristics and etching resistance required as a material for forming the mask pattern (hereinafter also referred to as "other characteristics"), it is also in the range that does not impair the effect of the embodiment. It may contain monomer units other than the first monomer unit.

As other properties required for the polymer X, for example, the obtained organic film has the property of being insoluble in organic solvents. It is a characteristic that is particularly required when the pattern forming material is applied to the multilayer mask structure. In the laminated mask structure, the organic film formed using this pattern forming material as described above is preferably formed as a base film between the photoresist film and the processed film. In this case, the other layer constituting the build-up mask is generally formed on the organic film, and it is formed by a so-called wet coating method in which the material constituting the layer is dissolved in an organic solvent or the like and applied. At this time, if the organic film formed using polymer X is soluble in the organic solvent used in the wet coating method, part of the organic film is dissolved, and there is a mixed layer that is mixed with the constituent materials of the layer formed on the organic film. Yu.

Therefore, the present inventors thought that in addition to the first monomer unit, a second monomer unit having a crosslinkable functional group at the end of the side chain was introduced in the polymer X to suppress the elution of the film components in the obtained organic film. Thereby, the organic film formed using the polymer X can be hardly dissolved in the organic solvent, and even when the upper layer of the organic film is formed by the wet coating method, the mixed layer is hardly formed. Hereinafter, the polymer X having the second monomer unit in addition to the first monomer unit may also be referred to as the crosslinkable polymer X.

The crosslinkable functional group possessed by the second monomer unit is not particularly limited as long as it is a functional group having crosslinkability, but from the viewpoint of storage stability, it is preferably by external energy such as heating or light irradiation. The functional group that exhibits crosslinking properties Examples of the crosslinkable functional group include glycidyl, oxetanyl, amino, azide, thiol, hydroxyl, carboxyl, etc., based on the structure after crosslinking, it has low activity to metal compounds, or crosslinking From the viewpoint that the energy required for the combined reaction is relatively mild, particularly preferred are glycidyl, oxetanyl, hydroxyl, carboxy, protected carboxy, etc.

As a constituent monomer of the second monomer unit, a monomer having a monovalent organic group having a crosslinkable functional group bonded to any carbon atom of an ethylene group is exemplified. A specific example of the second monomer unit is the monomer unit (2) represented by the following general formula (2).

In the general formula (2), R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom or a hydrocarbon group with 1 to 10 carbons. R ¹³ is a single bond or a carbon with 1 to 20 carbon atoms or between carbon and carbon atoms. A hydrocarbon group containing an oxygen atom, a nitrogen atom, and an ether bond at the end of the bond, and L is a crosslinkable functional group.

As a constituent monomer of the second monomer unit, a compound ester having a crosslinkable functional group at the end is preferably bonded to (meth)acrylate of (meth)acrylic acid, or substituted with a crosslinking property at the end Styrene derivatives of functional compounds.

Specific examples of (meth)acrylates having a glycidyl group among the (meth)acrylates that are the constituent monomers of the second monomer unit are compounds represented by the following general formula L1.

通式L1中，R為氫原子或甲基，Gly為縮水甘油基。m為0~3，R ¹⁵為碳數1~10之伸烷基。作為L1表示之(甲基)丙烯酸酯具體舉例為通式L1-1表示之(甲基)丙烯酸縮水甘油酯。以下各通式中之R為氫原子或甲基。

In the general formula L1, R is a hydrogen atom or a methyl group, and Gly is a glycidyl group. m is 0~3, and R ¹⁵ is an alkylene group with 1 to 10 carbon atoms. A specific example of the (meth)acrylate represented by L1 is glycidyl (meth)acrylate represented by the general formula L1-1. R in the following general formulae is a hydrogen atom or a methyl group.

A specific example of (meth)acrylic acid ester having oxetanyl group in the (meth)acrylic acid ester that becomes the constituent monomer of the second monomer unit is (meth)acrylic acid represented by the following general formula L2-1 (3- Ethyl-3-oxetanyl) methyl ester. R in the general formula below is a hydrogen atom or a methyl group.

A specific example of the styrene derivative having a glycidyl group among the styrene derivatives that are the constituent monomers of the second monomer unit is a compound represented by the following general formula L3.

The copolymer of the first monomer unit and the second monomer unit constituting the polymer X is preferably rich in randomness, as long as the combination of the first monomer unit and the second monomer unit is determined based on this viewpoint.

When the polymer X contained in the pattern forming material contains the second monomer unit, the polymer X may contain only one type of the second monomer unit, or two or more types. When polymer X contains one type of first monomer unit and two or more types of second monomer unit, polymer X may be a mixture of two or more copolymers containing the first monomer unit and each second monomer unit. It may also be a copolymer containing one type of first monomer unit and two or more types of second monomer unit.

In addition, when the polymer X contains two or more types of first monomer units and one type of second monomer unit, polymer X may contain two or more types of the second monomer unit and each of the first monomer units. The mixture of copolymers may also be a copolymer containing two or more types of first monomer units and one type of second monomer units.

When the polymer X contains the first monomer unit and the second monomer unit, in the case of a mixture of two or more copolymers or a copolymer of one type as described above, different polymer chains can be used The crosslinkable functional groups of the second monomer unit contained in it react and bond with each other, so that each main chain of the plural polymer is crosslinked and hardly melted. In addition, the reaction between crosslinkable functional groups is preferably performed by heating or light irradiation when forming an organic film.

The ratio of the second monomer unit in the polymer X is preferably 0.5 mol% or more and less than 20 mol%, and more preferably 1 mol% or more and less than the total monomer units constituting the polymer X Up to 10 mol%, more preferably 2 mol% or more and 10 mol% or less.

When the second monomer unit is less than 0.5 mol% of the total monomer units, the crosslinking of the polymer X is not fully carried out, and the insoluble polymer cannot be fully achieved, and the constituent components of the organic film will be dissolved in the upper layer of the organic film. In the wet coating solution. When the second monomer unit is 20 mol% or more of the entire monomer unit, the cross-linking density becomes too high, and the diffusion of the metal compound into the organic film is suppressed, and there is a possibility that the metalization cannot reach the depth of the organic film.

When the polymer X contains the second monomer unit, the first monomer unit can be selected from, for example, monomer units composed of monomers exemplified in Table 1. The monomer unit L1-1 can be selected as the second monomer unit, and the selected monomer units can be combined to form the polymer X.

Hereinafter, for the cross-linkable polymer X, the case where the first monomer unit is the monomer unit M-1 and the second monomer unit is the monomer unit L1-1 (but R is a methyl group) will be described as an example. . Hereinafter, when R in the monomer unit L1-1 is a methyl group, M is added to the end of the abbreviation of the monomer unit, and it is referred to as the monomer unit L1-1M. When R is a hydrogen atom, A is added at the end of the abbreviation of the monomer unit, which is called the monomer unit L1-1A. The same applies to other monomer units.

Crosslinkable polymer X is applicable to other first monomer units other than the first monomer unit system monomer unit M-1, and other second monomer units other than the second monomer unit system monomer unit L1-1M The following instructions.

The following chemical structural formula X11 represents the chemical structural formula of polymer X formed by combining monomer unit M-1 and monomer unit L1-1M. The polymer represented by the chemical structural formula X11 is hereinafter referred to as polymer X11. The following is the same for other polymers.

Polymer X11 is composed of monomer unit M-1 and monomer unit L1-1M. n2 represents the molar ratio of the monomer unit L1-1M to the entire monomer unit in the polymer X11, and n1 represents the molar ratio of the monomer unit M-1 to the entire monomer unit in the polymer X11. The total of n1 and n2 in the polymer X11 is 100 mol%. In the polymer X11, the monomer unit M-1 and the monomer unit L1-1M may alternately exist, or may exist randomly. Corresponding to the content ratio of each monomer unit, it is preferable that each monomer unit exists equally.

The polymer X contained in the pattern forming material is a cross-linkable polymer X, and is only composed of polymer X11. The n2 in polymer X11 is the same as the above description, preferably 0.5 mol% or more and less than 20 mol%, more preferably 1 mol% or more and less than 10 mol%, and still more preferably 2 mol% or more and less than 10 mol%. n1 is preferably more than 80 mol% and 99.5 mol% or less, more preferably more than 90 mol% and 99 mol% or less, and still more preferably more than 90 mol% and 98 mol% or less.

In addition, the crosslinkable polymer X may be a mixture of the polymer X11 and other crosslinkable polymers X. For example, it can be a polymer X (hereinafter referred to as polymer X12) containing other first monomer units such as monomer unit M-2 instead of monomer unit M-1 of the first monomer unit in polymer X11, or A mixture of polymer X (hereinafter referred to as polymer X13) of the bulk unit M-3.

When the crosslinkable polymer X is a mixture of polymer X11 and other crosslinkable polymers X, the content ratio of the first monomer unit to the second monomer unit in each crosslinkable polymer may not necessarily be The above range. As for the entire mixture, the content ratio of the first monomer unit to the second monomer unit is preferably in the above range.

For example, when the crosslinkable polymer X is a mixture of polymer X11 and polymer X12, the total of monomer unit M-1 and monomer unit M-2 is relative to the total monomer of polymer X11 and polymer X12 The unit is preferably more than 80 mol% and 99.5 mol% or less, more preferably more than 90 mol% and 99 mol% or less. In addition, the total of the monomer units L1-1 in the polymer X11 and the polymer X12 is preferably 0.5 mol% or more and less than 20 mol% relative to the total monomer units of the polymer X11 and the polymer X12. , More preferably 1 mol% or more and less than 10 mol%.

The adjustment of the ratio of each monomer unit in the crosslinkable polymer X is carried out by adjusting the ratio of monomers used during polymerization. The molecular weight (Mw) of the crosslinkable polymer X is preferably 1,000 to 100,000,000, and more preferably 2,000 to 100,000.

As the crosslinkable polymer X, the crosslinked structure when polymer X11 is used is shown in the chemical structural formula L-X11. As shown in the chemical structural formula L-X11, when the polymer X11 is cross-linked, the epoxy rings of the glycidyl group of the monomer unit L1-1M are opened and bonded to each other through -CH ₂ -CH(OH) -CH ₂ -bond and crosslink. In the chemical structural formula L-X11, n1 and n2 independently represent the molar ratio of the monomer unit M-1 and the monomer unit L1-1M in each polymer chain.

In addition, the epoxy ring can also adopt the chemical structural formula of some slight carboxylic acids in the system as shown in the chemical structural formula L-X12. In the chemical structural formula L-X12, na+nb=n2, n1 and n2 each independently represent the molar ratio of the monomer unit M-1 and the monomer unit L1-1M in each polymer chain.

The conditions for crosslinking the crosslinkable polymer X vary depending on the type of crosslinkable functional group possessed by the second monomer unit. For example, when the crosslinkable functional group is a glycidyl group or an oxetanyl group, the epoxy group or oxetanyl group is ring-opened and crosslinked. Therefore, the polymer X is crosslinked by heating or light irradiation under the conditions for opening the epoxy group or oxetanyl group. In addition, a curing agent may be used when the crosslinkable polymer X is crosslinked.

The curing agent is reactive to crosslinkable functional groups, and the crosslinkable functional groups can be bonded to each other via the curing agent. The curing agent promotes the cross-linking reaction, and the cross-linking of the polymers X with each other becomes easy. Therefore, the preferred hardener varies according to the type of the second monomer unit. For example, when the crosslinkable functional group of the second monomer unit is a glycidyl group, an amine compound, a compound having an acid anhydride skeleton, a compound having a carboxylic acid, and a compound having a hydroxyl group can be preferably used as the hardener.

The amine compound has plural primary amines or secondary amines in the skeleton. Amine compounds that can be used as hardeners include, for example, ethylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octa Methylene diamine, nonamethylene diamine, decamethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexaamine, 1, 2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine Phenyl diamine, m-xylyl diamine, p-xylyl diamine, isophorone diamine, 4,4'-methylene diphenylamine, diamine diphenyl diamine, diamino diamine Phenyl ether and so on.

The compound having an acid anhydride skeleton that can be used as the hardener includes, for example, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, succinic anhydride, itaconic anhydride, dodecenyl succinic anhydride, and the like.

Compounds with carboxylic acids that can be used as hardeners include, for example, hexahydrophthalic acid, 4-methylhexahydrophthalic acid, succinic acid, itaconic acid, dodecenyl succinic acid, citric acid, Terephthalic acid etc.

The compound having a hydroxyl group contains a plurality of hydroxyl groups in the skeleton. Examples of compounds having hydroxyl groups that can be used as hardeners include polyphenols, 1,4-benzenediol, 1,3-benzenediol, 1,2-benzenediol, and ethylene glycol.

In addition, in order to improve the reactivity of the curing agent other than the amine compound exemplified above, a curing accelerator having a tertiary amine may be added. As the hardening accelerator, there are, for example, cyanodiamide, 1,8-diazabicyclo(5,4,0)-undecene-7 or 1,5-diazabicyclo(4,3,0 )-Nonene-5, ginseng (dimethylaminomethyl)phenol, ethylene glycol, etc.

When the pattern forming material contains both the crosslinkable polymer X and the hardener, the amount of hardener is preferably 1 mol relative to the crosslinkable functional group of the crosslinkable polymer X. The ratio of the reactive group of the linking functional group is 0.01 to 1 mole.

The crosslinkable polymer X contained in the pattern forming material may further contain other monomer units (hereinafter referred to as "different monomer units") other than the first monomer unit and the second monomer unit as necessary. By making polymer X have different monomer units, it is possible to adjust the solubility of polymer X in organic solvents, the film-forming properties during coating, the glass transition point of the film after coating, and the heat resistance.

Examples of monomers constituting heterogeneous monomer units include styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 9-vinylanthracene, vinylbenzophenone, hydroxystyrene, and methyl (meth)acrylate. , (Meth) acrylic acid, methyl 4-vinyl benzoate, 4-vinyl benzoic acid, etc. The heterogeneous monomer unit may be composed of at least one of these monomers. The ratio of the heterogeneous monomer units to the total monomer units constituting the polymer X is preferably 50 mol% or less, more preferably 10 mol% or less, and still more preferably 1 mol% or less. By making the heterogeneous monomer unit less than 50 mol%, the content of the first monomer unit in the organic film can be kept high, and more metal compounds can be strongly bonded in the organic film.

In addition to the polymer X, the pattern forming material may contain components other than the polymer X as needed, within a range that does not impair the effect of this embodiment. As components other than the polymer X, the above-mentioned curing agents and curing accelerators are typically exemplified. Examples of components other than the curing agent and curing accelerator include thermal acid generators and photoacid generators. The content of components other than polymer X in the pattern forming material can be appropriately selected according to each component. For example, the hardener can be as described above. The content of the components other than the polymer X other than the hardener is preferably 1% by mass or less, and more preferably 0.1% by mass or less with respect to the total amount of the pattern forming material.

The method of using the pattern forming material to form an organic film can be a dry coating method or a wet coating method. When an organic film is formed by a dry coating method, the pattern forming material itself can be used to form an organic film by a dry coating method such as an evaporation method. When the organic film is formed by a wet coating method, it is more appropriate to apply a composition containing the pattern forming material and an organic solvent on the processed film, and then dry it to form an organic film.

(Implementation form of composition for pattern formation) The pattern forming composition of the embodiment (hereinafter also referred to as "composition") is formed on the aforementioned processed film of the substrate with the processed film, and the organic film is formed using the pattern forming material and patterned, and then the metal The composite film obtained by impregnating the compound in the aforementioned organic film is used as a mask pattern. It is used when processing the aforementioned processed film. It is a composition containing the pattern-forming material used to form the aforementioned organic film, and contains the pattern-forming material and An organic solvent that dissolves the pattern forming material, and the pattern forming material contains a polymer containing the first monomer unit represented by the general formula (1).

As the pattern forming material in the composition of the embodiment, this pattern forming material can be used. The composition of the embodiment can be used for the same purposes as described above for the pattern forming material. If the organic solvent in the composition of the embodiment is an organic solvent that can dissolve the pattern forming material, especially the polymer X contained in the pattern forming material, it is not particularly limited.

Examples of organic solvents for dissolving polymer X include aromatic hydrocarbons such as toluene, xylene, and mesitylene, ketones such as cyclohexanone, acetone, ethyl methyl ketone, and methyl isobutyl ketone, methyl Cellosolves such as cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate (PGMEA), etc., preferably soluble Fiber type. An organic solvent can be used in combination of two or more types as needed.

The content of the pattern forming material in the composition of the embodiment is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, and still more preferably 1 to 15% by mass relative to the entire composition. The content of the organic solvent in the composition of the embodiment is preferably 70 to 99% by mass, more preferably 80 to 99% by mass, and still more preferably 85 to 99% by mass relative to the entire composition. By making the content of the pattern forming material and the organic solvent in the composition of the embodiment fall within the above range, the formation of an organic film on the processed film by the wet coating method can be performed well.

The method of applying the composition of the embodiment to the processed film by a wet coating method can be a normal method. Specifically, spin coating and dip coating are preferable. Subsequently, the coating film from the composition is dried to remove the organic solvent to form an organic film. When the polymer X is a cross-linkable polymer X, a cross-linking treatment corresponding to the cross-linkable polymer X used in the formation of the organic film is performed, such as heating or light irradiation for cross-linking.

Here, when an organic film is formed using the composition of the embodiment, it is preferable to form the organic film under conditions that do not release -CR ¹ R ² R ³ from the first monomer unit. If -CR ¹ R ² R ^{3 is} detached from the first monomer unit during the formation of the organic film, there is a possibility that it will not be able to cause uniform metalization in the film thickness direction during subsequent metallization. The possibility of not being able to achieve a strong bond between the organic film and the metal compound is high.

(Pattern forming method and semiconductor device manufacturing method embodiment) The pattern forming method of the embodiment has the following steps (A1) to (C). (A1) A step of forming an organic film on a substrate using a pattern forming material containing a polymer containing monomer unit (1), (B) The step of patterning the organic film obtained in (A1), (C) The step of forming a composite film by impregnating the patterned organic film with a metal compound, and obtaining a mask pattern formed by the composite film.

The manufacturing method of the semiconductor device of the embodiment has the following steps (A) to (D). (A) A step of forming an organic film using a pattern forming material containing a polymer containing the monomer unit (1) on the processed film on the substrate with the processed film, (B) The step of patterning the organic film obtained in (A), (C) The step of impregnating a patterned organic film with a metal compound to form a composite film, and obtaining a mask pattern formed by the composite film, (D) The step of processing the processed film using the mask pattern.

The pattern forming material used in the pattern forming method of the embodiment and the method of manufacturing a semiconductor device can use the pattern forming material described above.

Hereinafter, the manufacturing method of the semiconductor device of the embodiment will be described using FIGS. 1A to 1E. Here, each step of (A1), (B), and (C) in the pattern forming method of the embodiment corresponds to each of (A), (B), and (C) in the method of manufacturing a semiconductor device of the embodiment step. Therefore, with regard to the steps (A1), (B), and (C) in the pattern forming method of the embodiment, the steps (A), (B), and (B), of the semiconductor device manufacturing method of the embodiment described below can be similarly applied (C) The specific method of each step.

1A to 1E are cross-sectional views showing each step of the manufacturing method of the semiconductor device of the embodiment. In the manufacturing method of the semiconductor device of the embodiment, the steps are performed in the order of FIGS. 1A to 1E.

1A is a cross-sectional view schematically showing the step (A), that is, the step of forming an organic film on the processed film of the substrate with the processed film using a pattern forming material. In this embodiment, in order to process the processed film 2 formed on the semiconductor substrate 1, the organic film 3 is formed from a pattern forming material.

In the step (A), first, the semiconductor substrate 1 on which the film 2 to be processed is formed is prepared. The film 2 to be processed may be a single-layer film such as a silicon oxide film, or a laminated film constituting a three-dimensional memory array such as a NAND flash memory. In the example shown in FIG. 1A, the film to be processed 2 is a laminated film in which a nitride film 21 and an oxide film 22 are alternately laminated.

Here, in the pattern forming method of the embodiment, the semiconductor substrate 1 may have the film 2 to be processed, but it may not be necessary. In addition, in the pattern forming method, a substrate of glass, quartz, mica, etc. may be used instead of the semiconductor substrate 1.

The pattern forming material is coated on the processed film 2 of the semiconductor substrate 1. In the case of dry coating methods such as vapor deposition, for example, coating the pattern forming material itself. In the case of wet coating methods such as spin coating and dip coating, the composition of the coating embodiment is applied. Next, drying to remove the organic solvent, heating for cross-linking, or light irradiation is performed as needed to form an organic film 3 on the film 2 to be processed.

Drying is performed under the wet coating method. The cross-linking is performed when the polymer X contained in the pattern forming material is a cross-linkable polymer. Cross-linking is achieved by bonding cross-linkable functional groups between different polymers. When a hardener is added, the bonding of the crosslinkable functional group is performed via the molecules of the hardener. During crosslinking, heating or light irradiation may be performed in order to promote the reaction.

In the case of crosslinking by heating, the heating temperature depends on the type of crosslinkable functional group or curing agent possessed by the second monomer unit. The heating temperature is preferably approximately 120°C or higher, more preferably 160°C or higher, and still more preferably 200°C or higher. However, the heating is preferably performed at a temperature that does not desorb -CR ¹ R ² R ³ from the first monomer unit. In addition, heating is preferably performed at a temperature that inhibits decomposition of the polymer main chain.

For example, when the C of -CR ¹ R ² R ³ in the first monomer unit is a tertiary carbon, the heating temperature is preferably approximately 250° C. or lower, more preferably 200° C. or lower. When C of CR ¹ R ² R ³ is grade 2 carbon, the heating temperature is preferably approximately 300°C or less, more preferably 250°C or less. -When C of CR ¹ R ² R ³ is grade 1 carbon, the heating temperature is preferably approximately 350° C. or lower, more preferably 300° C. or lower. In addition, in the case of the wet coating method, the heating is usually performed together with drying, that is, the organic solvent contained in the composition of the embodiment is also removed. In this way, the organic film 3 formed by the pattern forming material, or the organic film 3 obtained by crosslinking the polymer X in the pattern forming material is obtained.

1B and 1C are cross-sectional views schematically showing step (B), that is, the step of patterning the organic film 3 obtained in step (A). As shown in FIG. 1B and FIG. 1C, the organic film 3 functions as a base layer of the multilayer mask structure 6. FIG. 1B shows a state in which a silicon oxide film 4 as a functional film is formed by patterning on the organic film 3, and a photoresist pattern 5p is formed thereon.

The silicon oxide film 4 is formed by heating the SOG (spin-on glass) film formed on the organic film 3 at a specific temperature, for example, 150 to 300° C. by the following method. However, like the above, the heating is preferably performed at a temperature that does not desorb -CR ¹ R ² R ³ from the first monomer unit. The SOG film is formed by spin-coating a wet coating solution made by dissolving the components of the SOG film in an organic solvent on the organic film 3.

At this time, an anti-reflection film (not shown) may be formed on the silicon oxide film 4. The anti-reflective film can prevent reflection from the substrate when patterning the photoresist film formed by the following process and can be precisely exposed. As the anti-reflection film, materials such as novolac resin, phenol resin, polyhydroxystyrene, etc. can be used.

Next, a photoresist film is formed on the silicon oxide film 4, and the photoresist film is made into a photoresist pattern 5p using photolithography technology or imprint technology. The imprint technology is to drop a photoresist on the silicon oxide film 4, press the template with the fine pattern against the photoresist film, and irradiate ultraviolet rays to harden the photoresist film to form a photoresist pattern 5p.

Figure 1C shows that the photoresist pattern 5p is used as a mask, the silicon oxide film 4 is etched to form a silicon oxide film pattern 4p, and the photoresist pattern 5p and the silicon oxide film pattern 4p are used as the mask, and the organic etching process is performed. The film 3 is a cross-sectional view of the state after the organic film pattern 3p is formed. The etching of the silicon oxide film 4 is performed using a fluorine-based gas (F-based gas), and the etching of the organic film 3 is performed using an oxygen-based (O ₂ based gas). As shown in FIG. 1C, a structure in which an organic film pattern 3p, a silicon oxide film pattern 4p, and a photoresist pattern 5p are sequentially laminated is an example of the multilayer mask structure 6.

In addition, in the case of forming an anti-reflection film on the silicon oxide film 4, the anti-reflection film is patterned before the etching of the silicon oxide film 4. Furthermore, after the silicon oxide film pattern 4p is formed, the photoresist pattern 5p can be eliminated to adjust the film thickness of the photoresist pattern 5p. Furthermore, after the organic film pattern 3p is formed, the silicon oxide film pattern 4p can also be eliminated to adjust the film thickness of the silicon oxide film pattern 4p.

As shown in this embodiment, in the case where the organic film pattern 3p is formed by the multilayer mask structure 6, the patterned organic film (organic film pattern 3p) in step (C) is impregnated with a metal compound. For the composite film, before the step of obtaining the mask pattern formed by the composite film, the silicon oxide film pattern 4p and the photoresist pattern 5p on the upper layer of the organic film pattern 3p can also be removed.

FIG. 1D is a cross-sectional view showing the state after step (C). The organic film pattern 3p shown in FIG. 1C is metalized to form a mask pattern 3m, which is present on the processed film 2 on the semiconductor substrate 1. In addition, during the process from the formation of the organic film 3 to the formation of the organic film pattern 3p, the conditions are adjusted so that the first monomer unit derived from the polymer X has -CR ¹ R ² R ³ at the end of the side chain not to be detached. The metallization of the organic film pattern 3p thus formed is performed as follows, for example.

The laminated body with the processed film 2 and the organic film pattern 3p in sequence on the semiconductor substrate 1 is carried into the vacuum device, and the organic film pattern 3p is exposed to the gas or liquid of the metal compound such as TMA as a metal-containing fluid . At this time, as shown in the above reaction formula (F), the molecules of the metal compound are adsorbed on the carbonyl group of the first monomer unit of the polymer of the organic film pattern 3p, so that -CR ¹ R ² R ^{3 is} released. Then, for example, as shown in the monomer unit (1') in the reaction formula (F), a structure in which the metal compound (Al(CH ₃ ) _x ) is strongly bonded to the two oxygen atoms of the organic film is formed.

Since the metal compound is strongly bonded to the organic film pattern 3p as described above, the exposure treatment of the metal compound to the organic film pattern 3p is preferably performed under heating. The heating temperature is appropriately selected according to the type of the metal compound and the type of the first monomer unit, especially the type of -CR ¹ R ² R ³ . For example, when the metal compound is TMA and the C of -CR ¹ R ² R ³ of the first monomer unit is a tertiary carbon, the heating temperature is set to 50°C or higher, preferably 100°C or higher, so that -CR ¹ R ² R ^{3 is} easy to detach, which can make TMA strongly bond to the organic film.

In addition, when the metal compound is TMA and the C of -CR ¹ R ² R ³ of the first monomer unit is a secondary carbon, the heating temperature is set to 80°C or higher, preferably 100°C or higher, so that -CR ¹ R ² R ^{3 is} easy to detach, which can make TMA strongly bond to the organic film. Furthermore, when the metal compound is TMA and the C of -CR ¹ R ² R ³ of the first monomer unit is a first-grade carbon, the heating temperature is set to 100°C or higher, preferably 120°C or higher, so that -CR ¹ R ² R ^{3 is} easy to detach, which can make TMA strongly bond to the organic film. The upper limit of the heating temperature in this case is preferably set to 400°C from the viewpoint of preventing decomposition of the polymer main chain of the organic film pattern 3p, for example.

As the metal compound, a metal compound used in a CVD method or an atomic layer deposition (ALD: Atomic Layer Deposition) method can be used without particular limitation.

Examples of metals contained in the metal compound include aluminum, titanium, tungsten, vanadium, hafnium, zirconium, tantalum, and molybdenum. Among these organometallic compounds or halides, those having sufficiently small ligands can be used as metal compounds.

Specifically, the metal compound that can be used may include at least one of AlCl ₃ , TiCl ₄ , WCl ₆ , VCl ₄ , HfCl ₄ , ZrCl ₄ , TMA, and the like. In this embodiment, TMA is preferable.

From the above, the polymer constituting the organic film pattern 3p is metalized to become a mask pattern 3m formed by the composite film of the organic film and the metal compound. In addition, after the metal compound is bonded in the organic film pattern 3p, it can also be subjected to oxidation treatment such as exposing it to a water vapor environment. For example, in the case of using TMA as the metal compound in the above, TMA becomes aluminum hydroxide or the like by oxidation treatment. Oxidation treatment is usually carried out using oxidants such as water, ozone, and oxygen plasma. In addition, the oxidation treatment may be performed naturally by the moisture in the environment without special operation.

Next, as shown in FIG. 1E, using the mask pattern 3m as a mask, the processed film 2 is etched by RIE, IBE, etc., to form a patterned processed film 2p. Thereby, a processed film 2p having a processed shape with a high aspect ratio is formed.

Subsequently, a known method is used to form, for example, a memory cell array. For example, by the above-mentioned processing, a hole pattern is formed in the laminated film. The barrier layer, the charge storage layer, the tunnel layer, the channel layer, and the core layer are embedded in the hole pattern to form a memory structure. Subsequently, only the nitride film in the build-up film is removed through a slit formed separately from the hole pattern provided with the memory structure, and the conductive film is embedded instead. As a result, it becomes a laminated film in which an insulating film (oxide film) and a conductive film are alternately laminated. The conductive film in the laminated film can function as a character line.

Since the pattern forming material contains a polymer having the first monomer unit represented by the general formula (1), the organic film obtained by using it can strongly bond the metal compound by metallization. Moreover, the composite film obtained by metallization has high etching resistance, especially high IBE resistance. Therefore, if this pattern forming material is used, a mask pattern of 3m with high etching resistance can be obtained, and a processed shape with a high aspect ratio can be given to the processed film.

The polymer contained in this pattern forming material is a cross-linkable polymer that has, in addition to the first monomer unit, a second monomer unit having a cross-linkable functional group at the end of the side chain, when forming an organic film By cross-linking the polymers with each other, the resulting organic film can be made difficult to dissolve in organic solvents. Thereby, an overlayer film such as a functional film or its precursor film can be formed on the organic film by coating or dripping of a wet coating liquid. At this time, the mixing of the organic film and the upper film or its precursor film can be suppressed. In addition to the above SOG film, the upper layer film or its precursor film includes, for example, SOC (Spin On Carbon) film, TEOS (tetraethyl orthosilicate) film, photoresist film, etc., which can be designed for multilayer mask structure. The degree of freedom increased dramatically.

According to the pattern forming material, the organic film can be formed by spin coating, dip coating, vapor deposition and other methods. For example, it takes a long time to form a carbon deposition layer in the film using the CVD method used in the past, but according to the pattern forming material, an organic film that becomes a composite film with high etching resistance can be easily formed in a short time. The method of forming an organic film into a composite film by metallization is also a simple and economical method. Also, in the case of wet coating methods such as spin coating and dip coating, the composition of the embodiment can be used.

In addition, in the above embodiment, although the organic film pattern 3p is mainly metalized in the gas phase, it is not limited to this. The organic film pattern 3p can also be metalized in the liquid phase.

In addition, in the above-mentioned embodiment, as the laminated mask structure, the structure mainly has the organic film 3, the silicon oxide film 4, and the photoresist pattern 5p, but it is not limited to this. In addition to the above-mentioned multilayer mask structure, various films can be inserted, or several of the above-mentioned films can be reduced, and various configurations can be adopted.

In addition, in the above-mentioned embodiment, the mask pattern 3m is formed on the semiconductor substrate 1, but it is not limited to this. The mask pattern is not only formed on semiconductor substrates such as silicon, but also on substrates such as glass, quartz, mica, etc.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can also be implemented in various other forms, and various omissions, substitutions, changes, etc. can be made without departing from the scope of the spirit of the present invention. These embodiments or their changes are included in the invention described in the scope of the patent application and their equivalent scope in the same way as included in the scope or spirit of the invention. [Example]

The following examples are used to further describe the present invention in detail, but the present invention is not limited to these examples.

[Example 1~9] First, by the following method, a crosslinkable polymer X composed only of the first monomer unit and the second monomer unit is produced. The pattern forming composition containing the obtained polymer X and the organic solvent were used to prepare and evaluate the pattern forming composition. Examples 1 to 8 are examples, and example 9 is the previous example.

(Polymerization of cross-linkable polymer X) Using the amounts shown in Table 2 the constituent monomers of the first monomer unit and the constituent monomers of the second monomer unit shown in Table 2 were polymerized in the following order to obtain crosslinked Linked polymers X-1~X-8. The yield of the obtained polymers X-1~X-8 is about 80~90%. In general formula (1) using the amount shown in Table 2, R ¹ to R ³ are hydrogen, R ⁵ is a single bond, and R ⁴ is methyl methacrylate (in Table 2 it is represented by "MMA" ) As the constituent monomers of the second monomer unit, polymer XR was produced in the same manner as described above as a previous example and used as a comparison target.

Into a 100cc round-bottom flask, feed the constituent monomers of the first monomer unit or MMA, the constituent monomers of the second monomer unit, and 0.1 mmol of azobisisobutyronitrile (AIBN) as a polymerization initiator , Add about 5 mL of toluene as a polymerization solvent. After replacing the air in the flask with nitrogen, polymerize at 100°C for 8 hours. After the reaction was completed, the flask was opened to the atmosphere to stop the polymerization, and the reaction solution was dropped into a large excess of methanol to purify the polymer component by reprecipitation. The obtained solid was filtered, and the solid was dried in a vacuum for several days to obtain the desired polymer X.

(Pattern forming material and pattern forming composition) For polymers X-1~X-8 and polymer XR, as shown in Table 3, they correspond to the types of polymers. For polymers X-1~X-5 and polymer XR, for each polymer X and polymer XR Add citric acid (indicated as "CA" in Table 3) as a hardening agent at a ratio of 1 mole of glycidyl group to 0.5 mol. For other polymers X, no hardening agent is added, and patterns are formed. Materials 1-9 (Examples 1-9). For each of the obtained pattern forming materials 1 to 9, PGMEA was added so that the content of each pattern forming material became 10% by mass to prepare a pattern forming composition.

[Evaluation] The pattern forming composition containing pattern forming materials 1 to 9 is used to produce an organic film, and a composite film is produced by metallization by the following method. Evaluate the metallization properties of the organic film and the etching resistance of the resulting composite film.

(Metalization characteristics) Use pattern forming materials 1 to 9 to form an organic film on the Si substrate, and use TMA to perform metallization of the organic film to evaluate the metallization characteristics.

The obtained polymer material was used to form an organic film on the Si substrate, and the metalization of the organic film was performed using TMA to evaluate the metalization characteristics.

The Si substrate is used for 3 minutes UV cleaning treatment. Each of the above-mentioned pattern forming compositions was applied on the Si substrate by spin coating. The rotation number is adjusted to 2000~3500rpm according to the type of polymer. After coating, the solvent is removed by drying to form an organic film with a thickness of about 300nm. Furthermore, annealing is performed at 200°C to proceed a crosslinking reaction. The obtained Si substrate with organic film was cut into a 15mm square and used as a sample for metallization treatment.

The metallization is performed by an atomic layer deposition (ALD) film forming device. Specifically, the sample for metallization treatment is set in an ALD device, and after the gas phase TMA is introduced into the device until it reaches a specific pressure, the valve is closed, and the pressure in this state is maintained in an exposure mode for a specific time. The initial pressure is 900 Pa, and the holding time is 600 seconds. In addition, the pressure in the device is decomposed by TMA to generate methane, so it gradually increases over time. Through this operation, the TMA is coordinated to the unshared electron pair of the polymer X or the polymer XR in the organic film.

After the above-mentioned TMA exposure, the gas phase in the device is replaced with water vapor (H ₂ O) to rise to a specific pressure, and the valve is closed to maintain the pressure in this state for a specific time. The initial pressure is set to 300 Pa, the holding time is set to 200 seconds, and the temperature is the same as when exposed to TMA. In addition, the pressure in the device gradually decreases due to the consumption of H ₂ O and adhesion to the inner wall of the chamber. After the holding time in the H ₂ O filled state has elapsed, take out the metalized metalized sample from the device. Through this operation, TMA is oxidized to become aluminum hydroxide or aluminum oxide.

Here, although an ALD device is used for the above-mentioned metallization treatment, the above-mentioned operation is based on the impregnation of a polymer with TMA for the purpose, and is not the so-called atomic layer deposition (ALD) that deposits an atomic layer on a substrate. Therefore, compared with ordinary ALD, the exposure time of metal compounds is longer and the number of cycles is less.

The degree of metallization is measured by XPS, using the amount of Al per unit volume [atom%] of the metallized organic film as an index. The results are shown in Table 3.

(Etching characteristics) Reactive ion etching (RIE) using O ₂ gas or CF ₄ gas is performed for each of the metalized substrates with organic film (each substrate with composite film). The composite film thickness of each substrate with composite film before and after RIE was measured using an atomic force microscope (AFM), and the film thickness difference before and after RIE was used as the etching amount, and the etching rate per etching time [nm/sec] was calculated. The results are shown in Table 3. In Table 3, "as spun" refers to the etching rate measured in the state before metallization, and "metallization" refers to the etching rate measured for each metalized organic film.

(1) O ₂ RIE O ₂ RIE is performed using CI-300L (manufactured by SAMCO) under the conditions of power: 50 W, bias voltage 5 W, flow: 5 sccm, and pressure: 3 Pa.

(2) CF ₄ RIE CF ₄ RIE uses CI-300L, with power: 50W, bias 10W, flow: 5sccm, pressure: 3Pa.

The etching resistance to O ₂ RIE increases sharply as the degree of metallization increases. A composite film composed of a polymer material with an ester bond (-C(=O)-O-) in the side chain has higher etching resistance to O ₂ RIE. This is considered to be due to the fact that there are many carbonyl groups in the constituent elements, which facilitates metallization, which increases the etching resistance to O ₂ RIE. In addition, the etching resistance to CF ₄ RIE increases as the degree of metallization increases.

(3) IBE Ion beam etching (IBE) is performed for each of the above-mentioned metallized substrates with organic film (each substrate with composite film). The composite film thickness of each composite film-attached substrate before and after IBE was measured using an atomic force microscope (AFM), and the film thickness difference before and after IBE was used as the etching amount, and the etching rate per etching time [nm/sec] was calculated.

(4) Assuming the RIE resistance of the memory hole is assumed to be close to the RIE conditions of the memory hole of the 3-dimensional memory, using a mixed gas of C ₄ F ₆ : 80 sccm, Ar: 100 sccm, O ₂ : 54 sccm, and N ₂ : 50 sccm Conditions for etching. The difference in film thickness before and after etching was used as the etching amount, and the etching rate per etching time [nm/sec] was calculated.

As shown in Table 3, it can be seen that the composite film formed using this pattern forming material has higher etching resistance than Example 9 of the previous example. And it can be seen that the composite film obtained by using the pattern forming materials of Examples 6 to 8 containing the aromatic ring-containing polymer X-6 to 8 has resistance to each etching, and the use of the aromatic ring-containing polymer X-1 to 5 The composite film obtained from the pattern forming materials of Examples 1 to 5 is higher than that.

[Example 10~22] In order to confirm that increasing the proportion of aromatic rings in polymer X can improve the etching resistance, the polymers X10-22 shown in Table 4 below were prepared, and the etching resistance of the pattern forming materials of Examples 10-22 (Examples) including them was performed The evaluation.

Specifically, the etching resistance of each of the pattern forming material containing polymer X-10 and the pattern forming material containing polymer X-11 was evaluated. The first monomer unit of the polymer X-10 series contains tertiary butyl methacrylate in the same ratio, and the first monomer unit of the polymer X-11 series contains tertiary butyl-4-ethylene in the same ratio. Benzoic acid, except for the copolymers of the same composition.

In addition, in order to make the pattern forming material have a structure in which more aromatic rings are contained and the metal is enclosed by the carbonyl group like the compound (1') of reaction formula (F), polymers X-12-22 are produced. First, as heterogeneous monomer units containing aromatic rings, styrene (indicated by "St" in Table 4), 1-vinylnaphthalene (indicated by "1-VN" in Table 4), and 2-vinylnaphthalene ( "2-VN" in Table 4), 9-vinylanthracene ("9-VN" in Table 4), the polymers X12~15 shown in Table 4 were produced, and pattern forming materials containing them were made Evaluation of each etching resistance.

Furthermore, polymers X16-22 containing two types of first monomer units containing aromatic rings and one type of second monomer units were produced, and the respective etching resistance evaluations of the pattern forming materials containing them were performed.

(Polymer X10~22 polymerization) Use the amounts shown in Table 4 for the constituent monomers of the first monomer unit, the constituent monomers of the heterogeneous monomer unit, and the constituent monomers of the second monomer unit shown in Table 4, by using the aforementioned polymers X1~X -8 Polymerize in the same sequence to obtain crosslinkable polymers X-10~X-22. The yield of the obtained polymers X-10~X-22 is about 80~90%.

(Preparation of pattern forming materials and pattern forming composition) For polymers X-10~X-22, no hardener is added, and pattern forming materials 1~22 are made respectively (Examples 10~22). For each of the obtained pattern forming materials 10-22, PGMEA was added so that the content of each pattern forming material became 10% by mass to prepare a pattern forming composition.

[Evaluation] Using the pattern forming composition containing pattern forming materials 1 to 22, an organic film was produced, and metallization was performed in the same manner as in Examples 1 to 9 above to produce a composite film. Evaluate the metallization properties of the organic film and the etching resistance of the resulting composite film. The results are shown in Table 5.

As shown in Table 5, it can be seen that the composite film obtained by using the pattern forming material containing polymer X-11 has higher etching resistance than the composite film obtained using the pattern forming material containing polymer X-10. In this way, it was confirmed that the pattern forming material contained more aromatic rings had higher etching resistance. In addition, the composite films obtained by using the pattern forming materials of Examples 12 to 22 also confirmed high etching resistance.

As shown in Table 3 and Table 5, the composite film formed using this pattern forming material has high etching resistance. In particular, in the etching conditions of the mixed gas similar to the RIE process for forming the memory holes of the three-dimensional memory, it is confirmed that the etching resistance after all metalization is higher than before.

References to related applications This application is based on the priority benefit of the previous Japanese Patent Application No. 2019-044105 filed on March 11, 2019 and claims the benefit, and the entire content is included by citation.

1: Semiconductor substrate 2: Processed film 2p: Patterned film to be processed 21: Nitride film 22: Oxide film 3: Organic film 3m: mask pattern 3p: Organic film pattern 4: Silicon oxide film 4p: Silicon oxide film pattern 5p: photoresist pattern 6: Multilayer mask structure

FIG. 1A is a diagram showing one step of the method of manufacturing a semiconductor device of the embodiment. FIG. 1B is a diagram showing one step of the manufacturing method of the semiconductor device of the embodiment. FIG. 1C is a diagram showing one step of the manufacturing method of the semiconductor device of the embodiment. FIG. 1D is a diagram showing a step of the manufacturing method of the semiconductor device of the embodiment. FIG. 1E is a diagram showing one step of the manufacturing method of the semiconductor device of the embodiment.

1: Semiconductor substrate 2: Processed film 2p: Patterned film to be processed 3: Organic film 3m: mask pattern 3p: Organic film pattern 4: Silicon oxide film 4p: Silicon oxide film pattern 5p: photoresist pattern 6: Multilayer mask structure 21: Nitride film 22: Oxide film

Claims (7)

A pattern forming material, which is on the aforementioned processed film on a substrate with a processed film, and after forming an organic film with the aforementioned pattern forming material and patterning, the aforementioned organic film is impregnated with a metal compound to form a composite The film is used as a mask pattern when processing the aforementioned processed film; and it contains the first monomer unit represented by the following general formula (1) and the second having a crosslinkable functional group at the end of the side chain A polymer of monomer units,

However, in the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group that may contain an oxygen atom. At least one of these is a hydrocarbon group, and the total carbon number of these is 1-13 These can be combined with each other to form a ring, R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a single bond or a carbon number of 1-20, which can contain oxygen, nitrogen, and sulfur atoms between carbon-carbon atoms or at the end of the bond For the hydrocarbon group, the hydrogen atom can be replaced by a halogen atom. Such as the pattern forming material of claim 1, wherein in the aforementioned general formula (1), one or two of R ¹ , R ² and R ³ are hydrogen atoms. The pattern forming material of Claim 1, which further contains a hardener reactive with the aforementioned crosslinkable functional group. A pattern-forming composition containing the pattern-forming material of any one of claims 1 to 3 and an organic solvent capable of dissolving the aforementioned pattern-forming material. A pattern forming method that uses a pattern forming material to form an organic film on a substrate. After patterning the organic film, the organic film is impregnated with a metal compound to form a composite film to obtain a mask pattern containing the composite film In the pattern forming method, the aforementioned pattern forming material contains a polymer containing a first monomer unit represented by the following general formula (1) and a second monomer unit having a crosslinkable functional group at the end of the side chain,

However, in the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group that may contain an oxygen atom. At least one of these is a hydrocarbon group, and the total carbon number of these is 1-13 These can be combined with each other to form a ring, R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a single bond or a carbon number of 1-20, which can contain oxygen, nitrogen, and sulfur atoms between carbon-carbon atoms or at the end of the bond For the hydrocarbon group, the hydrogen atom can be replaced by a halogen atom. Such as the pattern forming method of claim 5, wherein in the aforementioned general formula (1), one or two of R ¹ , R ² and R ³ are hydrogen atoms. A method for manufacturing a semiconductor device, which uses a pattern forming material to form an organic film on the processed film on a substrate with a processed film, and after patterning the organic film, the organic film is impregnated with a metal compound to form a composite film , To obtain a mask pattern including the aforementioned composite film, and use the aforementioned mask pattern to process the aforementioned processed film semiconductor device manufacturing method; the aforementioned pattern forming material contains the first unit represented by the following general formula (1) A polymer of a bulk unit and a second monomer unit having a crosslinkable functional group at the end of the side chain,

However, in the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group that may contain an oxygen atom. At least one of these is a hydrocarbon group, and the total carbon number of these is 1-13 These can be combined with each other to form a ring, R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a single bond or a carbon number of 1-20, which can contain oxygen, nitrogen, and sulfur atoms between carbon-carbon atoms or at the end of the bond For the hydrocarbon group, the hydrogen atom can be replaced by a halogen atom.

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