KR20190008024A - Method for planarization of block copolymer layer and method for forming pattern - Google Patents

Abstract

The present application provides a method for planarization of a block copolymer film, capable of accurately adjusting a thickness of a film including a block copolymer, maintaining a constant surface roughness, and reducing a defect in the film including the block copolymer. The method for the planarization of the block copolymer film includes a step of etching a film including a block copolymer, which is formed on a substrate on which a trench is formed while covering an upper portion of the trench.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of planarizing a block copolymer film and a method of forming a pattern,

The present application relates to a planarization method and a pattern formation method of a block copolymer film.

The block copolymer has a molecular structure in which polymer blocks having different chemical structures are linked via covalent bonds. The block copolymer can form a periodically arranged structure such as a sphere, a cylinder or a lamella by phase separation. The shape and size of the domain of the structure formed by the self-assembly phenomenon of the block copolymer can be extensively controlled by, for example, the kind of the monomer forming each block or the relative ratio between the blocks.

Due to these properties, the block copolymer is considered to be applied to a variety of next generation nano devices such as nanowire fabrication, quantum dots or metal dots, or to a lithography method capable of forming a high-density pattern on a predetermined substrate .

The technique of adjusting the orientation of the self-assembled structure of the block copolymer horizontally or vertically on various substrates occupies a very large proportion in the practical application of the block copolymer. Typically, the orientation of the nanostructure in the film of the block copolymer is determined by which block of the block copolymer is exposed to the surface or air. In general, since a plurality of substrates are polar and air is non-polar, a block having a larger polarity among the blocks of the block copolymer is wetted to the substrate, and a block having a smaller polarity is wetted at the interface with air ). Therefore, various techniques have been proposed to allow the blocks having different characteristics of the block copolymer to be wetted simultaneously on the substrate side, and the most representative technique is the adjustment of the orientation using neutral surface preparation.

The present application provides a planarization method of a block copolymer film which can accurately control the thickness of a film including a block copolymer and maintain a constant surface roughness and reduce defects in the film including the block copolymer.

In this specification, 'and / or' are used to mean at least one of the elements listed before and after.

As used herein, the term monovalent or divalent hydrocarbon group may mean a monovalent or divalent moiety derived from a compound or derivative of carbon and hydrogen, unless otherwise specified. Examples of the compound composed of carbon and hydrogen in the above include alkane, alkene, alkyne or aromatic hydrocarbon.

As used herein, the term alkyl group may mean an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, unless otherwise specified. The alkyl group may be a straight chain, branched or cyclic alkyl group and may be optionally substituted by one or more substituents.

As used herein, unless otherwise specified, the term alkoxy group may mean an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy groups may be straight, branched or cyclic alkoxy groups and may optionally be substituted by one or more substituents.

As used herein, the term alkenyl or alkynyl group means an alkenyl group or alkynyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms unless otherwise specified can do. The alkenyl or alkynyl group may be linear, branched or cyclic and may optionally be substituted by one or more substituents.

As used herein, unless otherwise specified, the alkylene group may mean an alkylene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkylene group may be a straight, branched or cyclic alkylene group and may optionally be substituted by one or more substituents.

As used herein, the term alkenylene group or alkynylene group means an alkenylene group or an alkynylene group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms, It can mean a group. The alkenylene or alkynylene group may be linear, branched or cyclic and may optionally be substituted by one or more substituents.

As used herein, the term "aryl" group or "arylene group" means, unless otherwise specified, one benzene ring structure, two or more benzene rings connected together sharing one or two carbon atoms, Or a monovalent or di-valent residue derived from a compound or a derivative thereof.

The aryl group or the arylene group may be, for example, an aryl group having 6 to 30 carbon atoms, 6 to 25 carbon atoms, 6 to 21 carbon atoms, 6 to 18 carbon atoms, or 6 to 13 carbon atoms unless otherwise specified.

The term aromatic structure in this application may mean the aryl group or the arylene group.

As used herein, the term alicyclic ring structure means a cyclic hydrocarbon structure other than an aromatic ring structure unless otherwise specified. The alicyclic ring structure may be, for example, an alicyclic ring structure having 3 to 30 carbon atoms, 3 to 25 carbon atoms, 3 to 21 carbon atoms, 3 to 18 carbon atoms, or 3 to 13 carbon atoms unless otherwise specified .

The term single bond in the present application may mean that no separate atom is present at the site. For example, in the structure represented by A-B-C, when B is a single bond, it may mean that no atom exists at a site represented by B and A and C are directly connected to form a structure represented by A-C.

Examples of the substituent which may optionally be substituted in the present application include an alkyl group, an alkenyl group, an alkynyl group, an alkylene group, an alkenylene group, an alkynylene group, an alkoxy group, an aryl group, an arylene group, a linear chain or an aromatic structure, An alkenyl group, an alkynylene group, an alkenyl group, an alkynyl group, an alkenyl group, an alkynyl group, an alkenyl group, an alkynyl group, an alkynyl group, An alkoxy group, an aryl group, and the like, but the present invention is not limited thereto.

The present application relates to a method for planarizing a block copolymer film. The method of the present application may comprise etching a film comprising a block copolymer formed on a substrate on which a trench is formed to cover the top of the trench. The formation of the film including the block copolymer to cover the top of the trench may mean that the film including the block copolymer is formed so as to surround the upper portion of the mesa structure of the trench described later. As described above, a film including a block copolymer may be formed so as to surround the upper portion of the trench, and a film of the block copolymer may also be formed in the trench and on the upper portion of the mesa structure forming the trench.

Generally, when a film including a block copolymer is formed on a substrate on which a guide pattern such as a trench is formed, the size, depth, and / or spacing of the guide pattern structure may not be constant. In this case, even if a film containing a block copolymer is formed by controlling the concentration of the spin coating solution, it is difficult to control the thickness of the film uniformly and defects of the block copolymer pattern due to unevenness of the film thickness occur. The method of the present application can form a film comprising a block copolymer of appropriate thickness regardless of the size, depth and / or spacing of the guide pattern such as trenches by etching the film comprising the block copolymer formed to surround the trench have.

The trenches may be a structure formed by a mes structure spaced apart from each other on a surface of a substrate, and one or more trenches may be formed on the substrate. For example, the mesa structure may each be in the form of a line or a hole. Such a mesa structure may be disposed on the surface of the substrate at a certain distance from each other. The mesa structures may be disposed on the surface of the substrate at substantially regular intervals. At least two or more mesa structures may be formed on the surface of the substrate. That is, the number of trenches formed by the mesa structure on the surface of the substrate may be one or more. The number of the mesa structures and the number of the trenches is not particularly limited and may be adjusted depending on the application. The mesa structure may serve to guide the self-assembled structure of the block copolymer formed when a film containing an induced self-assembling material such as a block copolymer is formed in the trench formed by the mesa structure.

In one example, the spacing D, height H and / or width W of the mesa structure spaced apart to form the trenches is not particularly limited and may be selected depending on the type and application of the block copolymer formed on the substrate And the like. For example, the ratio (D / H) of the interval (D) to the height (H) of the mesa structure may be in the range of 0.1 to 10. Also, the ratio (D / W) of the interval (D) to the width (W) between the mesa structures may be in the range of 0.5 to 10. The ratio (D / H or D / W) may be changed according to the intended use. In this specification, the term D of the term mesa structure means the shortest distance between neighboring mesa structures spaced apart, and the distance D may be, for example, about 10 nm to 500 nm. In the present specification, the height H of the term mesa structure is the dimension of the mesa structure measured in the upward direction along the normal direction of the substrate surface with respect to the surface of the substrate, and may be, for example, about 1 nm to 100 nm. In the present specification, the term (W) of the mesa structure is a dimension of a mesa structure measured along a direction perpendicular to the normal direction of the substrate surface, and may be, for example, about 10 nm to 500 nm.

A method of forming the above-described mesa structure on a substrate is not particularly limited, and a known method can be applied. For example, the mesa structure can be formed by etching the substrate in an appropriate manner, or by depositing a suitable material on the substrate.

The type of the substrate to which the method of the present application is applied is not particularly limited. As the substrate, for example, various kinds of substrates requiring formation of a pattern on the surface may be used for application to each of the above-described applications. Examples of such a substrate include semiconductor substrates such as a silicon substrate, a silicon germanium substrate, a GaAs substrate, a silicon oxide substrate, and the like. As the substrate, for example, a finert field effect transistor (finFETs) or a substrate which is applied to the formation of other electronic devices such as diodes, transistors or capacitors, etc., can be used. In addition, other materials such as ceramics may be used as the substrate according to the application, and the type of the substrate that can be applied in the present application is not limited thereto.

In the method of the present application, the ratio (T ₁ / H) of the thickness (T ₁ ) of the film including the block copolymer to the height (H) of the trench before the step of etching may be one or more. The ratio (T ₁ / H) may be 1 or more, 1.02 or more, 1.04 or more, 1.06 or more, 1.08 or more, 1.10 or more, 1.12 or more, 1.14 or more, 1.16 or more, 1.18 or more or 1.20 or more. The upper limit of the ratio (T ₁ / H) is not particularly limited, and may be, for example, 20 or less, 15 or less, or 10 or less. The thickness T _{1 of} the film including the block copolymer may be a value measured in the normal direction with respect to the bottom surface of the trench. If the film thickness (T ₁₎ is the above-described film thickness (T ₁₎ and the ratio (T ₁ / H) of the height (H) of the trench satisfies the above range is not particularly limited, for example, 1 to ㎚ 100㎚ Lt; / RTI >

The ratio (T ₂ / H) of the thickness (T ₂ ) of the film including the block copolymer to the height (H) of the trench after the step of etching by the method of the present application may be 1 or less. The ratio (T ₂ / H) may be 1 or less, 0.98 or less, 0.95 or less, 0.93 or less, or 0.90 or less, but is not limited thereto. The lower limit of the ratio (T ₂ / H) is not particularly limited, and may be, for example, 0.1 or more, 0.15 or more, or 0.2 or more. The ratio of the thickness (T ₂ ) of the film including the block copolymer after planarization to the height (H) of the trench (T ₂ / H) is maintained within the above range, so that the structure formed of the block copolymer has the desired structure . The thickness T _{2 of} the film including the block copolymer may be a value measured in the normal direction with respect to the bottom surface of the trench. If the film thickness (T ₂₎ is the above-described film thickness (T ₂₎ and non (T ₂ / H) of the height (H) of the trench satisfies the above range is not particularly limited, for example, 1 to ㎚ 100㎚ Lt; / RTI >

In one example of the present application, the step of etching the block copolymer may be performed by an inductively coupled plasma (RIE) method or a reactive ion etching (RIE) method. For example, reactive ion etching Can be used to etch the block copolymer. The reactive ion etching (RIE) may refer to a method of etching the substrate by a combination of physical impact and chemical reaction in such a manner that an etching gas is made into a plasma state and a gas in a plasma state is collided with a substrate using upper and lower electrodes . The apparatus for performing the reactive ion etching is not particularly limited. As the apparatus, a known reactor can be used. Exemplary reactors include Plasmalab System of Oxford Instruments or 100RIE-101iPH of Samco Chemical.

The step of etching may use fluorocarbon and oxygen as an etching gas. The fluorocarbon has two or more fluorine atoms, and the ratio (F / C) of the number of atoms of the fluorine atom (F) to the number of carbon atoms (C) may be two or more. The fluorocarbon may be, for example, CHF ₃ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₄ F ₁₀ , C ₅ F ₁₀ , CCl ₂ F ₂ , CF ₃ I, CF ₃ Br, CHF ₂ COF, and CF ₃ COF, but the present invention is not limited thereto. The upper limit of the F / C ratio is not particularly limited, but may be 4 or less, for example. In the method of the present application, it is possible to perform uniform etching compared to etching using conventional Ar / O ₂ gas by using fluorocarbon having two or more fluorine atoms and an F / C ratio of 2 or more and oxygen as an etching gas, The roughness of the film surface can be improved.

The etching gas may have a ratio of flow rate of fluorocarbon to oxygen of 0.2 to 1.2. The ratio of the flow rate of the fluorocarbon and oxygen may be 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more, and 1.2 or less, 1.1 or less or 1 or less. Also, the flow rate of the fluorocarbon may be 50 sccm or less. The flow rate is less than or equal to 48 sccm, less than or equal to 46 sccm, less than or equal to 44 sccm, less than or equal to 42 sccm, less than or equal to 40 sccm, less than or equal to 40 sccm, less than or equal to 38 sccm, less than or equal to 36 sccm, less than or equal to 34 sccm, less than or equal to 32 sccm, less than or equal to 30 sccm, less than or equal to 28 sccm, And the lower limit is not particularly limited, but may be, for example, 0 sccm or more.

Further, when the fluorocarbon and oxygen are used together, the flow rate of oxygen may be 100 sccm or less. The flow rate is not more than 95 sccm, not more than 90 sccm, not more than 85 sccm, not more than 80 sccm, not more than 75 sccm, not more than 70 sccm, not more than 65 sccm, not more than 60 sccm, not more than 55 sccm, not more than 50 sccm, not more than 45 sccm, not more than 40 sccm , 36 sccm or less, 34 sccm or less, or 32 sccm or less, and the lower limit is not particularly limited but may be 0 sccm or more. It is possible to maintain the etching rate uniformly by controlling the ratio of the flow rate of the fluorine carbon and the oxygen to the flow rate of the truant carbon and / or the flow rate of the oxygen of the etching gas to the above range, and to maintain the surface roughness of the etched film constant have.

In one example, the applied power of the etching step of the present application may be less than or equal to 50W. The applied power may mean a power applied to a high frequency induction coil of the reactive ion etching reactor, and may be 47 W or less, 45 W or less, 43 W or less, 40 W or less, 37 W or less, 34 W or less, 32 W or less, or 30 W or less, but is not limited thereto. The lower limit of the applied power may be 10 W or more, 13 W or more, 16 W or more, 18 W or 20 W or more, but is not limited thereto. By maintaining the applied electric power of the etching step of the present application within the above range, the film including the block copolymer to be etched can be uniformly etched and the roughness can be kept constant, and the roughness of the film including the residual block copolymer after etching is increased Can be prevented.

In one example, the block copolymer according to the present application may comprise a unit represented by the following formula (1).

[Chemical Formula 1]

X is a single bond, an oxygen atom, a sulfur atom, -S (= O) _2- , a carbonyl group, an alkylene group, an alkenylene group, an alkynylene group, -C (= O) (= O) ₂ -, an alkylene group, an alkenylene group or an alkynylene group, and Y is -X ₁ - or -X ₁ -C (= O) -, wherein X ₁ is an oxygen atom, a sulfur atom, Is a monovalent substituent group including a ring structure having a chain having 8 or more chain forming atoms connected thereto.

X in the formula 1 may be a single bond, an oxygen atom, a carbonyl group, -C (= O) -O- or -OC (= O) - or -C (= O) -O- in another example, But is not limited to.

The monovalent substituent of Y in formula (1) includes a chain structure formed by at least eight chain-forming atoms.

The term chain forming atom in the present application means an atom forming a straight chain structure of a certain chain. The number of chain-forming atoms is calculated by the number of atoms forming the longest straight chain, and the number of the other atoms bonded to the chain-forming atoms (for example, the chain- A hydrogen atom bonded to the carbon atom in the case of a carbon atom, etc.) is not calculated. Also, in the case of a branched chain, the number of chain-forming atoms can be calculated as the number of chain-forming atoms forming the longest chain. For example, when the chain is an n-pentyl group, all of the chain-forming atoms are carbon, the number is 5, and even if the chain is a 2-methylpentyl group, all the chain-forming atoms are carbon, The chain-forming atom may be exemplified by carbon, oxygen, sulfur or nitrogen, and a suitable chain-forming atom may be carbon, oxygen or nitrogen, or carbon or oxygen. The number of chain-forming atoms may be 8 or more, 9 or more, 10 or more, 11 or more, or 12 or more. The number of the chain-forming atoms may be 30 or less, 25 or less, 20 or less, or 16 or less.

The unit of the formula (1) can make the block copolymer exhibit excellent self-assembling properties.

In one example, the chain may be a straight chain hydrocarbon chain such as a straight chain alkyl group. In this case, the alkyl group may be an alkyl group having 8 or more carbon atoms, 8 to 30 carbon atoms, 8 to 25 carbon atoms, 8 to 20 carbon atoms, or 8 to 16 carbon atoms. At least one of the carbon atoms of the alkyl group may optionally be substituted with an oxygen atom, and at least one hydrogen atom of the alkyl group may be optionally substituted by another substituent.

In Formula (1), Y may include a cyclic structure, and the chain may be connected to the cyclic structure. Such a ring structure can further improve the self-assembling property and the like of the block copolymer formed by the monomer. The ring structure may be an aromatic structure or an alicyclic structure.

The chain may be directly connected to the ring structure, or may be connected via a linker. The linker is an oxygen atom, a sulfur _{atom, -NR 1 -, S (=} O) 2 -, a carbonyl group, an alkylene group, alkenylene group, alkynylene _{group, -C (= O) -X 1} - or - X ₁ -C (= O) -, etc., wherein R ₁ may be hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group or an aryl group, X ₁ represents a single bond, , -NR ₂ -, -S (═O) ₂ -, an alkylene group, an alkenylene group or an alkynylene group, and R ₂ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group, have. An appropriate linker may be an oxygen atom or a nitrogen atom. The chain may be connected to the aromatic structure via, for example, an oxygen atom or a nitrogen atom. In this case, the linker may be an oxygen atom, or -NR ₁ - (wherein R ₁ may be hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group or an aryl group).

Y in the formula (1) may be represented by the following formula (2) in one example.

(2)

In the formula 2 P is an arylene group, Q is a single bond, an oxygen atom or -NR ₃ - and, at the R ₃ is a hydrogen atom, alkyl group, alkenyl group, alkynyl group, alkoxy group or aryl group, Z is 8 Or more of the chain forming atoms. When Y in the general formula (1) is a substituent of the general formula (2), P in the general formula (2) may be directly connected to X in the general formula (1).

Suitable examples of P in formula (2) include, but are not limited to, an arylene group having 6 to 12 carbon atoms, such as a phenylene group.

In formula (2), Q is an oxygen atom or -NR ₁ - (where R ₁ is hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group or an aryl group) as a suitable example.

As a suitable example of the unit of the formula (1), R is hydrogen or an alkyl group such as hydrogen or an alkyl group having 1 to 4 carbon atoms, X is -C (= O) -O-, In Formula (2), P is an arylene group having 6 to 12 carbon atoms or phenylene, Q is an oxygen atom, and Z is the above-mentioned chain having 8 or more chain-forming atoms.

Accordingly, examples of suitable examples of the formula (1) include the following formula (3).

(3)

R is hydrogen or an alkyl group having 1 to 4 carbon atoms, X is -C (= O) -O-, P is an arylene group having 6 to 12 carbon atoms, Q is an oxygen atom, Z is a chain- Lt; RTI ID = 0.0 > 8 < / RTI >

The block copolymer of the present application may contain units represented by the general formulas (1), (2) and / or (3) to exhibit excellent self-assembling properties of the block copolymer, 0.0 > lamellar < / RTI > structure or a vertically oriented sphere structure.

In one example, the block copolymer of the present application may comprise a unit represented by the following formula (4).

[Chemical Formula 4]

In formula 4 X ₂ is a single bond, an oxygen atom, sulfur _{atom, -S (= O) 2 -} , alkylene group, alkenylene group, alkynylene _{group, -C (= O) -X 1} - or -X ₁ -C (= O) - and, in the X ₁ is a single bond, oxygen atom, sulfur _{atom, -S (= O) 2 -} , alkylene group, alkenyl group or alkynyl group, and W is at least one halogen Is an aryl group containing an atom. In the above, W may be an aryl group substituted with at least one halogen atom, for example, an aryl group having 6 to 12 carbon atoms substituted with at least 2, at least 3, at least 4, or at least 5 halolene atoms.

In addition, the block copolymer may include a unit represented by the following formula (5).

[Chemical Formula 5]

In formula 5 X ₂ is a single bond, an oxygen atom, sulfur _{atom, -S (= O) 2 -} , alkylene group, alkenylene group, alkynylene _{group, -C (= O) -X 1} - or -X ₁ -C (= O) - and, in the X ₁ is a single bond, oxygen atom, sulfur atom, -S (= O) ₂ -, and the alkylene, alkenylene or alkynylene group, R ₁ to R ₅ is Each independently represents a hydrogen atom, an alkyl group, a haloalkyl group or a halogen atom, and each of R ₁ to R ₅ contains one or more halogen atoms.

X ₂ in Formula 5 may be a single bond, an oxygen atom, an alkylene group, -C (= O) -O- or -OC (= O) - in another example.

In formula (5), R ₁ to R ₅ each independently represents a hydrogen atom, an alkyl group, a haloalkyl group or a halogen atom, and R ₁ to R ₅ each independently represent one or more, two or more, three or more, four or more, , For example, a fluorine atom. The halogen atoms contained in R ₁ to R ₅ , for example, the fluorine atom, may be 10 or less, 9 or less, 8 or less, 7 or less, or 6 or less.

The block copolymer according to the present application includes the units of the above formula (4) or (5), so that the block copolymer exhibits excellent self-assembling properties.

The block copolymer of the present application may be embodied in a periodic structure including a sphere, a cylinder, a gyroid or a lamellar through self-assembly. In the case of spores or lamellas of the above structures, the block copolymer may be present in a vertically oriented state.

A specific method for producing such a block copolymer in the present application is not particularly limited as long as it includes a unit represented by the above-mentioned formulas.

For example, the block copolymer can be prepared by the LRP (Living Radical Polymerization) method using the above monomers. For example, anionic polymerization in which an organic rare earth metal complex is used as a polymerization initiator, or an organic alkali metal compound is used as a polymerization initiator in the presence of an inorganic acid salt such as a salt of an alkali metal or an alkaline earth metal, An atomic transfer radical polymerization method (ATRP) using an atom transfer radical polymerization agent as a polymerization initiator, and an atom transfer radical polymerization agent as a polymerization initiator, (ATRP), Initiators for Continuous Activator Regeneration (ATR), Atomic Transfer Radical Polymerization (ATRP), Inorganic Reducing Agent Reversible Additive - Reversible addition-cleavage chain transfer using cleavage chain transfer agent And a method using the polymerization method of (RAFT) or an organic tellurium compound, etc. as an initiator, may be subject to a suitable method among these methods is selected.

For example, the block copolymer can be prepared in a manner that includes polymerizing a reactant containing monomers capable of forming the block in the presence of a radical initiator and a living radical polymerization reagent by living radical polymerization .

The method of forming the other block included in the copolymer together with the block formed by using the monomer in the production of the block copolymer is not particularly limited and may be appropriately selected in consideration of the kind of the desired block, Block can be formed.

The preparation of the block copolymer may further include, for example, a step of precipitating the polymerization product produced through the above process in the non-solvent.

The type of the radical initiator is not particularly limited and may be appropriately selected in consideration of the polymerization efficiency. For example, AIBN (azobisisobutyronitrile), ABCN (1,1'-Azobis (cyclohexanecarbonitrile) Azo compounds such as 2,2'-azobis- (2,4-dimethylvaleronitrile), peroxides such as BPO (benzoyl peroxide) or DTBP (di-t-butyl peroxide) Can be used.

The living radical polymerization process can be carried out in the presence of a base such as, for example, methylene chloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, benzene, toluene, acetone, chloroform, tetrahydrofuran, dioxane, monoglyme, diglyme, Amide, dimethylsulfoxide or dimethylacetamide, and the like.

Examples of the non-solvent include ethers such as alcohols such as methanol, ethanol, n-propanol or isopropanol, glycols such as ethylene glycol, n-hexane, cyclohexane, n-heptane or petroleum ether, But is not limited thereto.

The present application also relates to a pattern forming method. The step of selectively removing any one of the polymer segments of the block copolymer forming the self-assembled structure after forming the metal-containing layer may be further included. The method of selectively removing one block of the block copolymer in the above method is not particularly limited. For example, a method of removing a relatively soft block by irradiating an appropriate electromagnetic wave, for example, ultraviolet light, (Inductively Coupled Plasma) etching or Reactive Ion Etching (RIE) may be used. For example, a polymer segment of a block copolymer may be selectively removed by reactive ion etching . The reactive ion etching may be performed according to a known method, and the etching conditions are not particularly limited. For example, argon or oxygen may be used as a reactive gas.

The pattern forming method of the present application may further include the step of etching the substrate using the polymer film from which a polymer segment has been removed as a mask. The step of selectively etching the substrate using the polymer membrane having the polymer segment removed as a mask is not particularly limited and may be performed by, for example, a reactive ion etching step using CF ₄ / Ar ions or the like, A step of removing the polymer membrane from the substrate by an oxygen plasma treatment or the like can also be performed.

The flattening method of the block copolymer film of the present application can maintain the surface roughness constant and reduce the defects of the film including the block copolymer while accurately controlling the thickness of the film including the block copolymer.

1 and 2 are AFM images of a polymer film by etching time in the planarization method of the present application.
Fig. 3 shows the result of measuring the thickness of the polymer film with time in the planarization method of the present application.
4 is an SEM image of the polymer film before the etching process of the flattening method of the present application.
5 is an SEM image of a polymer membrane to which the flattening method of the present application is applied.
6 is an SEM image of a film comprising a block copolymer formed on a substrate.
7 is an SEM image of a substrate on which a hole trench is formed.
8 is an AFM image of the polymer film before the etching process of the planarization method of the present application.
9 is an SEM image of a polymer membrane to which the planarization method of the present application is applied.
10 is an SEM image of a polymer membrane according to Comparative Example 1. Fig.
11 is an SEM image of the polymer membrane according to Comparative Example 2. Fig.
12 is an SEM image of the polymer membrane according to Comparative Example 3. Fig.

Hereinafter, the present application will be described in detail by way of examples and comparative examples according to the present application, but the scope of the present application is not limited by the following examples.

Production Example 1. Synthesis of monomer (A)

The compound (DPM-C12) shown below was synthesized in the following manner. Hydroquinone (10.0 g, 94.2 mmol) and 1-bromododecane (23.5 g, 94.2 mmol) were placed in a 250-mL flask and dissolved in 100 mL of acetonitrile. Potassium carbonate was added and reacted at 75 DEG C for about 48 hours under a nitrogen atmosphere. After the reaction, the remaining potassium carbonate was filtered off and acetonitrile used in the reaction was removed. A mixed solvent of DCM (dichloromethane) and water was added thereto to work up, and the separated organic layers were collected and dehydrated by passing through MgSO ₄ . Subsequently, the title compound (4-dodecyloxyphenol) (9.8 g, 35.2 mmol) as white solid was obtained in a yield of about 37% using dichloromethane in column chromatography.

4-dodecyloxyphenol (9.8 g, 35.2 mmol) synthesized in the flask, methacrylic acid (6.0 g, 69.7 mmol) DCC (dicyclohexylcarbodiimide) (10.8 g, 52.3 mmol) And DMAP (p-dimethylaminopyridine) (1.7 g, 13.9 mmol) was added, 120 mL of methylene chloride was added, and the reaction was allowed to proceed at room temperature under nitrogen for 24 hours. After completion of the reaction, the salt (urea salt) produced during the reaction was filtered off and the remaining methylene chloride was removed. The resulting product was recrystallized in a mixed solvent of methanol and water (1: 1 mixture) to obtain the title compound (7.7 g, 22.2 mmol) as a white solid. 1H-NMR (DMSO-d6) 63%. ≪ / RTI >

(A)

In formula (A), R is a straight chain alkyl group having 12 carbon atoms.

Production Example 2. Synthesis of block copolymer (A-1)

2.0 g of the monomer (A) of Preparation Example 1, 64 mg of cyanoisopropyldithiobenzoate as a reversible addition fragmentation chain transfer (RAFT) reagent, 23 mg of azobisisobutyronitrile (AIBN) as a radical initiator and 5.34 mL of benzene were dissolved in 10 mL of Schlenk flask , And the mixture was stirred at room temperature for 30 minutes under a nitrogen atmosphere, and then subjected to Reversible Addition Fragmentation Chain Transfer (RAFT) at 70 ° C for 4 hours. After the polymerization, the reaction solution was precipitated in 250 mL of methanol, which was an extraction solvent, and dried under reduced pressure to give a giant initiator of pink color. The yield of the macromonomer was about 82.6% by weight and the number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were 9,000 and 1.16, respectively. 0.3 g of macroinitiator, 2.7174 g of pentafluorostyrene monomer, and 1.306 mL of benzene were placed in a 10 mL Schlenk flask and stirred at room temperature for 30 minutes under a nitrogen atmosphere. Reversible Addition Fragmentation Chain Transfer (RAFT) Respectively. After the polymerization, the reaction solution was precipitated in 250 mL of methanol, which was an extraction solvent, and then dried under reduced pressure to obtain a pale pink block copolymer. The block copolymer is derived from the monomer (A) of Production Example 1, and has 12 chain-forming atoms (the number of carbon atoms of R in the formula (A)) and includes a molecular segment A and a polymer segment B derived from the pentafluorostyrene monomer .

The trench substrate was prepared in the following manner. A silicon wafer was used as the substrate. On the substrate, a layer of SiO 2 was formed to a thickness of about 200 nm by a known deposition method. Subsequently, a bottom anti-reflective coating (BARC) was coated on the SiO 2 layer to a thickness of about 60 nm, and a PR (positive-tone resist) layer was coated thereon to a thickness of about 400 nm . Then, the PR layer was patterned by a KrF stepper exposure method. Subsequently, using the patterned PR layer as a mask, the BARC layer and the SiO layer were etched by RIE (Reactive Ion Etching) method, and the residue was removed to form a trench structure.

The block copolymer (A-1) was applied on the trench to form a polymer film. Specifically, the coating solution prepared by diluting the block copolymer (A-1) with toluene in a solid concentration of 1.5% by weight was spin-coated, dried at room temperature for about 1 hour, For about 1 hour to form a self-assembled film. FIG. 6 is a SEM image of a self-assembled structure formed in the above manner, and it can be seen that a film is formed on the substrate.

The polymer membrane was etched using a reactive ion etching reactor (Plasmalab System 100, Oxford Instruments). In the etching process, the flow rate of C ₄ F ₈ / O ₂ was adjusted to 20/20 sccm, the applied electric power of the RF coil was maintained at 25 W, and the pressure was adjusted to 10 mTorr. FIG. 1 is an AFM image of a polymer film etched for 10 seconds under the above conditions, and FIG. 2 is an AFM image of a polymer film etched for 20 seconds under the same conditions. As shown in FIGS. 1 and 2, when the polymer film is etched according to the planarization method of the present application, it can be confirmed that the surface roughness is kept constant.

FIG. 3 shows the result of measuring the thickness of the polymer film with time in the application of the flattening method of the present application. 3, it can be seen that the flattening method of the present application can reduce the thickness of the polymer film uniformly according to the etching time.

FIG. 4 is an SEM image of the substrate before etching, and it can be confirmed that the polymer film is formed in the form of surrounding the trench.

5 is an SEM image after performing the etching for 75 seconds under the above etching condition. It can be seen from FIG. 5 that the polymer film does not remain on the upper part of the mesa structure forming the trench, but the polymer film remains while maintaining the self assembled structure of the block copolymer.

Example 2

A trench was fabricated in the same manner as in Example 1, except that the shape of the trench was a hole shape. Figure 7 shows the fabricated hole trenches. The block copolymer (A-1) was applied on the prepared hole trench to form a polymer film. Specifically, the coating solution prepared by diluting the block copolymer (A-1) with toluene in a solid concentration of 1.5% by weight was spin-coated, dried at room temperature for about 1 hour, For about 1 hour to form a self-assembled film. FIG. 8 is an AFM photograph of a self-assembled structure formed in the above manner. It can be seen that a film is formed on the substrate so as to surround the hole trench so that only the block copolymer cylinder structure is confirmed on the surface.

The polymer membrane was etched using a reactive ion etching reactor (Plasmalab System 100, Oxford Instruments). In the etching process, the flow rate of C ₄ F ₈ / O ₂ was adjusted to 20/20 sccm, the applied electric power of the RF coil was maintained at 25 W, and the pressure was adjusted to 10 mTorr. 9 is an SEM image after etching for 60 seconds under the above etching conditions. It can be seen from FIG. 9 that the polymer membrane remains in the upper portion of the mesa structure forming the hole trench, while the polymer membrane remains in the hollow trench while maintaining the self-assembling structure of the cylinder of the block copolymer.

Comparative Example 1

The substrate on which the polymer film prepared in Example 1 was formed was etched under the following conditions. In the etching process, the flow rate of Ar / O ₂ was adjusted to 40/20 sccm, the applied electric power of the RF coil was maintained at 25 W, and the pressure was adjusted to 10 mTorr. 10 is an SEM image of the polymer film after performing the etching for 20 seconds under the above conditions. As shown in FIG. 10, it can be seen that the roughness of the film greatly increased even though the film including the same block copolymer was etched.

Comparative Example 2

The flow rate of C ₄ F ₈ / O ₂ was adjusted to 40/20 sccm, the RF power of the RF coil was maintained at 100 W, the pressure was adjusted to 15 mTorr, and the etching time Etching was carried out under the same conditions as in Example 1 except that the etching rate was changed to 60 seconds. 11 is an SEM image of the polymer film after etching under the conditions of Comparative Example 2, and it can be confirmed that the roughness of the polymer film after etching is greatly increased.

Comparative Example 3

The etching rate was adjusted by controlling the flow rate of C ₄ F ₈ / O ₂ to 40/40 sccm, maintaining the applied power of the RF coil at 100 W, adjusting the pressure to 15 mTorr, The etching was carried out under the same conditions as in Example 1, except that the temperature was adjusted to 30 seconds. 12 is an SEM image of the polymer film after etching under the conditions of Comparative Example 3, and it can be confirmed that the structure of the block copolymer of the polymer film after etching is lost.

Claims (15)

A method for planarizing a block copolymer film, comprising: etching a film including a block copolymer formed on a substrate on which a trench is formed to cover an upper portion of the trench.
The method of claim 1, wherein the ratio (T ₁ / H) of the height (H) of the trench before etching to the thickness (T ₁ ) of the film comprising the block copolymer measured with respect to the bottom surface of the trench is at least 1 A method for planarizing a copolymer film.
The flattening method of a block copolymer film according to claim 1, wherein the ratio (T ₂ / H) of the thickness (T ₂ ) of the block copolymer film to the height (H) of the trench after the step of etching is 1 or less.
6. The method of claim 1, wherein the step of etching the block copolymer is a reactive ion etching (RIE).
2. The method of claim 1, wherein the etching comprises using an etching gas comprising fluorocarbon and oxygen,
Wherein the fluorocarbon has two or more fluorine atoms and the ratio (F / C) of the fluorine atom (F) to the carbon atom (C) is 2 or more.
6. The method for planarizing a block copolymer film according to claim 5, wherein the ratio of flow rate of fluorocarbon and oxygen is 0.2 to 1.2.
6. The method of claim 5, wherein the flow rate of the fluorocarbon is 50 sccm or less.
6. The method of claim 5, wherein the flow rate of oxygen is 100 sccm or less.
The flattening method of a block copolymer film according to claim 5, wherein the applied electric power of a high frequency induction coil (RF coil) used for reactive ion etching is 50 W or less.
2. The method of claim 1, wherein the block copolymer is a flattening method of a block copolymer film comprising a unit represented by the following formula
[Chemical Formula 1]

X is a single bond, an oxygen atom, a sulfur atom, -S (= O) _2- , a carbonyl group, an alkylene group, an alkenylene group, an alkynylene group, -C (= O) (= O) ₂ -, an alkylene group, an alkenylene group or an alkynylene group, and Y is -X ₁ - or -X ₁ -C (= O) -, wherein X ₁ is an oxygen atom, a sulfur atom, Is a monovalent substituent group including a ring structure having a chain having 8 or more chain forming atoms connected thereto.
The method of claim 1, wherein the block copolymer is a planarization method of a block copolymer film comprising a unit represented by the following formula (4)
[Chemical Formula 4]

In formula 4 X ₂ is a single bond, an oxygen atom, sulfur _{atom, -S (= O) 2 -} , alkylene group, alkenylene group, alkynylene _{group, -C (= O) -X 1} - or -X ₁ -C (= O) - and, in the X ₁ is a single bond, oxygen atom, sulfur _{atom, -S (= O) 2 -} , alkylene group, alkenyl group or alkynyl group, and W is at least one halogen Is an aryl group containing an atom.
The method for planarizing a block copolymer film according to claim 1, wherein the block copolymer forms a self-assembled structure.
13. The method of claim 12, wherein the self-assembled structure of the block copolymer is a cylinder, sphere or lamellar structure.
13. The method of claim 12, further comprising selectively removing any one of the polymer segments of the block copolymer forming the self-assembled structure.
15. The method for planarizing a block copolymer film according to claim 14, further comprising the step of etching the substrate using the polymer film from which a polymer segment is removed as a mask.

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