Patent Application
20160215085
This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2015-0011324, filed on Jan. 23, 2015, in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety.
The inventive concepts relate to methods of forming a pattern. More particularly, the inventive concepts relate to methods of purifying a block copolymer and methods of forming a pattern using the block copolymer.
Fine patterns should be needed to manufacture highly integrated semiconductor devices. To integrate a lot of elements in a small area, a size of an individual element should be as small as possible. In addition, a pitch including a width of each of patterns constituting the individual element and a space between the patterns should be as small as possible. As design rules of semiconductor devices have been rapidly reduced, it may be difficult to form patterns having a fine pitch by a resolution limitation of a photolithography process used to form the patterns. Thus, it may be required to develop a direct self-assembly (DSA) method induced using a block copolymer.
Embodiments of the inventive concepts may provide methods of purifying a block copolymer capable of improving purity thereof.
Embodiments of the inventive concepts may also provide methods of separating a block copolymer capable of easily manufacturing various block copolymers.
Embodiments of the inventive concepts may also provide methods of forming a pattern using the block copolymer.
In an embodiment, the purifying method may include providing a block copolymer including a first polymer block and a second polymer block, the block copolymer formed by polymerizing a first monomer and a second monomer, forming a first mixture solution by dissolving the block copolymer and a first adsorbent in a first solvent, the first adsorbent having adsorbability with respect to the first polymer block having a first molecular weight or more in the first solvent, forming a first complex by adsorbing the block copolymer on the first adsorbent, and separating the first complex from the first mixture solution.
In another embodiment, the purifying method may further include forming a second mixture solution by dissolving the block copolymer and a second adsorbent in a second solvent, the second adsorbent interacting with the second polymer block in the second solvent, forming a second complex by adsorbing the block copolymer on the second adsorbent, and separating the second complex from the second solvent.
In another embodiment, the block copolymer may include a first block copolymer, a second block copolymer, and a third block copolymer. The first polymer block of the first block copolymer may have a molecular weight equal to the first molecular weight, the first polymer block of the second block copolymer may have a molecular weight greater than the first molecular weight, and the first polymer block of the third block copolymer may have a molecular weight smaller than the first molecular weight.
In another embodiment, the second complex may include the first block copolymer adsorbed on the second adsorbent, and the second block copolymer may not be adsorbed on the second adsorbent.
In another embodiment, providing the block copolymer may further include providing a first homopolymer formed by polymerization of the first monomer, the first homopolymer including the same polymer as the first polymer block, and providing a second homopolymer formed by polymerization of the second monomer, the second homopolymer including the same polymer as the second polymer block.
In another embodiment, the first complex may further include the first homopolymer adsorbed on the first adsorbent. The second homopolymer may not be adsorbed on the first adsorbent.
In another embodiment, the first homopolymer may not be adsorbed on the second adsorbent in the second solvent.
In another embodiment, the second solvent may include a main solvent in which a first polymer has a high solubility and in which the main solvent has a volume ratio of 50 vol % to 70 vol %, and a co-solvent in which the first polymer has a low solubility and in which the co-solvent has a volume ratio of 30 vol % to 50 vol %. In some embodiments the first polymer can be, or comprises, a hydrophilic polymer, or predominantly comprises a hydrophilic polymer. In yet other embodiments, the first polymer can be a block copolymer that comprises a hydrophilic polymer block, or can be a block copolymer that predominantly comprises a hydrophilic polymer block. In still other embodiments, the hydrophilic polymer or hydrophilic polymer block may be, e.g., polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinylpyrrolidone (PVP), or polyethylene oxide (PEO).
In another embodiment, the first polymer block may include a hydrophobic polymer, and the first adsorbent may include a silica particle coated with an alkyl chain.
In another embodiment, the first solvent may include a main solvent in which a second polymer has a high solubility and in which the main solvent has a volume ratio of about 50 vol % to about 70 vol %, and a co-solvent having in which the second polymer has a low solubility and in which the co-solvent has a volume ratio of 30 vol % to 50 vol %. In some embodiments the second polymer can be, or comprises, a hydrophobic polymer, or predominantly comprises a hydrophobic polymer. In yet other embodiments, the second polymer can be a block copolymer that comprises a hydrophobic polymer block, or can be a block copolymer that predominantly comprises a hydrophobic polymer block. In yet other embodiments, the hydrophobic polymer or hydrophobic polymer block may be, e.g., polystyrene (PS).
In another embodiment, the main solvent may include methylene chloride, and the co-solvent may include acetonitrile.
In another embodiment, the purifying method may further include forming a first block copolymer composition by filtering and precipitating the first mixture solution from which the first complex is separated. A composition ratio of the first block copolymer composition may be different from that of the block copolymer.
In another embodiment, the purifying method may further include adding the first complex into a solvent having high solubility to desorb the block copolymer from the first adsorbent.
In yet another embodiment, the purifying method may include polymerizing a first monomer and a second monomer to form a block copolymer, the block copolymer including a hydrophobic polymer block and a hydrophilic polymer block, forming a first mixture solution by dissolving the block copolymer and a hydrophobic adsorbent n a first solvent, forming a first complex by adsorbing the block copolymer on the hydrophobic adsorbent, the hydrophobic adsorbent having adsorbability with respect to the hydrophobic polymer block having a first molecular weight or more in the first solvent, and separating the first complex from the first solvent. Polymerizing the first monomer and the second monomer may include forming a first homopolymer and a second homopolymer. The first homopolymer may include the same polymer as the hydrophobic polymer block, and the second homopolymer may include the same polymer as the hydrophilic polymer block. The block copolymer may include a first block copolymer, a second block copolymer, and a third block copolymer. The hydrophobic polymer block of the first block copolymer may have a molecular weight equal to the first molecular weight, the hydrophobic polymer block of the second block copolymer may have a molecular weight greater than the first molecular weight, and the hydrophobic polymer block of the third block copolymer may have a molecular weight smaller than the first molecular weight.
In yet another embodiment, the purifying method may further include forming a second mixture solution by dissolving the block copolymer and a hydrophilic adsorbent in a second solvent, the hydrophilic adsorbent interacting with the hydrophilic polymer block in the second solvent, forming a second complex by adsorbing the block copolymer on the hydrophilic adsorbent, and separating the second complex from the second solvent.
In yet another embodiment, the purifying method may further include forming a second block copolymer composition by filtering and precipitating the second mixture solution from which the second complex is separated. A composition ratio of the second block copolymer composition may be different from that of the block copolymer.
In yet another embodiment, the purifying method may further include forming a first block copolymer composition by filtering and precipitating the first mixture solution from which the first complex is separated. A composition ratio of the first block copolymer composition may be different from that of the block copolymer.
In yet another embodiment, the first complex may include the hydrophobic adsorbent, the first block copolymer, the second block copolymer, and the first homopolymer. The third block copolymer and the second homopolymer may not be adsorbed on the hydrophobic adsorbent.
In yet another embodiment, the hydrophobic adsorbent may include a silica particle coated with an alkyl chain.
In still another embodiment, the method of forming a pattern may include forming a lower layer on a substrate, providing a block copolymer including a hydrophobic polymer block and a hydrophilic polymer block, forming a mixture solution by dissolving the block copolymer and a hydrophobic adsorbent in a solvent, the hydrophobic adsorbent having adsorbability with respect to the hydrophobic polymer block having a first molecular weight or more in the solvent, forming a complex by adsorbing the block copolymer on the hydrophobic adsorbent, separating the complex from the solvent, desorbing the block copolymer from the complex, depositing the desorbed block copolymer on the lower layer to form a block copolymer layer, thermally treating the block copolymer layer to form a first block portion and a second block portion, removing the second block portion to form a guide opening exposing the lower layer, and etching the lower layer exposed through the guide opening.
In still other embodiments, provided is a memory system and/or a semiconductor device comprising patterns, formed by methods according to the present inventive concept.
The inventive concepts will become more apparent in view of the attached drawings and accompanying detailed description.
The inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the inventive concepts are shown. The advantages and features of the inventive concepts and methods of achieving them will be apparent from the following exemplary embodiments that will be described in more detail with reference to the accompanying drawings. It should be noted, however, that the inventive concepts are not limited to the following exemplary embodiments, and may be implemented in various forms. Accordingly, the exemplary embodiments are provided only to disclose the inventive concepts and let those skilled in the art know the category of the inventive concepts. In the drawings, embodiments of the inventive concepts are not limited to the specific examples provided herein and are exaggerated for clarity.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular terms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present.
Similarly, it will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. In contrast, the term “directly” means that there are no intervening elements. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Additionally, the embodiment in the detailed description will be described with sectional views as ideal exemplary views of the inventive concepts. Accordingly, shapes of the exemplary views may be modified according to manufacturing techniques and/or allowable errors. Therefore, the embodiments of the inventive concepts are not limited to the specific shape illustrated in the exemplary views, but may include other shapes that may be created according to manufacturing processes. Areas exemplified in the drawings have general properties, and are used to illustrate specific shapes of elements. Thus, this should not be construed as limited to the scope of the inventive concepts.
It will be also understood that although the terms first, second, third etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, a first element in some embodiments could be termed a second element in other embodiments without departing from the teachings of the present invention. Exemplary embodiments of aspects of the present inventive concepts explained and illustrated herein include their complementary counterparts. The same reference numerals or the same reference designators denote the same elements throughout the specification.
Moreover, exemplary embodiments are described herein with reference to cross-sectional illustrations and/or plane illustrations that are idealized exemplary illustrations. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etching region illustrated as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.
As appreciated by the present inventive entity, devices and methods of forming devices according to various embodiments described herein may be embodied in microelectronic devices such as integrated circuits, wherein a plurality of devices according to various embodiments described herein are integrated in the same microelectronic device. Accordingly, the cross-sectional view(s) illustrated herein may be replicated in two different directions, which need not be orthogonal, in the microelectronic device. Thus, a plan view of the microelectronic device that embodies devices according to various embodiments described herein may include a plurality of the devices in an array and/or in a two-dimensional pattern that is based on the functionality of the microelectronic device.
The devices according to various embodiments described herein may be interspersed among other devices depending on the functionality of the microelectronic device. Moreover, microelectronic devices according to various embodiments described herein may be replicated in a third direction that may be orthogonal to the two different directions, to provide three-dimensional integrated circuits.
Accordingly, the cross-sectional view(s) illustrated herein provide support for a plurality of devices according to various embodiments described herein that extend along two different directions in a plan view and/or in three different directions in a perspective view. For example, when a single active region is illustrated in a cross-sectional view of a device/structure, the device/structure may include a plurality of active regions and transistor structures (or memory cell structures, gate structures, etc., as appropriate to the case) thereon, as would be illustrated by a plan view of the device/structure.
A method of forming a block copolymer according to embodiments of the inventive concepts will be described.
Referring to
The block copolymer may be defined as a polymer including at least two polymer blocks of which ends are connected to each other by a covalent bond. For example, each of the block copolymer BCP1, BCP2, and BCP3 may include a first polymer block P1, P1′, and P1″, and a second polymer block P2, P2′, and P2″, respectively. The second polymer block P2, P2′, and P2″ may have a different property from the first polymer block P1, P1′, and P1″. For example, the first polymer block P1, P1′, and P1″ may include a hydrophilic polymer, e.g., polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinylpyrrolidone (PVP), or polyethylene oxide (PEO). The second polymer block P2, P2′, and P2″ may include a hydrophobic polymer, e.g., polystyrene (PS).
The polymer product may include impurities formed by the polymerization process. For example, a first homopolymer HP1 and a second homopolymer HP2 may be formed in the polymerization process. The first homopolymer HP1 may be synthesized by polymerization of the first monomers, and the second homopolymer HP2 may be synthesized by polymerization of the second monomers. The first homopolymer HP1 may have hydrophilic properties, and the second homopolymer HP2 may have hydrophobic properties. For example, the first homopolymer HP1 may include the same polymer as the first polymer block P1, P1′, and P1″, and the second homopolymer HP2 may include the same polymer as the second polymer block P2, P2′, and P2″. As the amount of the first homopolymer HP1 and the amount of the second homopolymer HP2 increase in the polymerization, the content ratio of the block copolymer BCP1, BCP2 or BCP3 may be reduced in the polymerization products.
The polymerization products may include first, second, and third block copolymers BCP1, BCP2, and BCP3. The first to third block copolymers BCP1, BCP2, and BCP3 may include the first polymer blocks P1, P1′, and P1″, respectively, each having sizes or fractions in block copolymers BCP1, BCP2, and BCP3 that are different from one other. For example, in some embodiments, the size or fraction of the first polymer block P1 in the first block copolymer BCP1 may be smaller than that of the first polymer block P1′ in the second block copolymer BCP2 and greater than that of the first polymer block P1″ in the third block copolymer BCP3. In this example, the first to third block copolymers BCP1, BCP2, and BCP3 may have the same or about the same molecular weight or may have similar molecular weights to each other. The size or fraction of the second polymer block P2 in the first block copolymer BCP1 may be greater than that of the second polymer block P2′ in the second block copolymer BCP2 and smaller than that of the second polymer block P2″ in the third block copolymer BCP3. The size or the fraction of the first polymer block P1 may correspond to a molecular weight of the first polymer block P1 in a block copolymer. The first block copolymer BCP1 may include the first polymer block P1 having a first molecular weight. The second block copolymer BCP2 may include the first polymer block P1′ having a second molecular weight that is greater than the first molecular weight of the first polymer block P1 in the first block copolymer BCP1. The third block copolymer BCP3 may include the first polymer block P1″ having a third molecular weight smaller than the first molecular weight of the first polymer block P1 in the first block copolymer BCP1. The first block copolymer BCP1 may be the main product of the polymer product. Each of the second and third block copolymers BCP2 and BCP3 may be a minor product or an impurity in the forming of the polymers. As content ratios of the second and third block copolymers BCP2 and BCP3 increase in the polymer product, the content ratio of the first block copolymer BCP1 may decrease. Alternatively, the polymerization method and polymerization conditions for forming the polymers may be controlled, so the second block copolymer BCP2 or the third block copolymer BCP3 may become the main product in the polymer product.
Referring to
Referring to
Referring to
If the first solvent 110 includes the main solvent of the volume ratio higher than 70 vol %, the first homopolymer HP1, the first block copolymer BCP1, and the second block copolymer BCP2 may interact more strongly with the first solvent 110 than with the hydrophilic adsorbent 100. Thus, the first homopolymer HP1, the first block copolymer BCP1, and the second block copolymer BCP2 may not be adsorbed onto the hydrophilic adsorbent 100. According to embodiments of the inventive concepts, the volume ratio of the main solvent in the first solvent 110 may be adjusted, and thus, the first homopolymer HP1, the first block copolymer BCP1, and the second block copolymer BCP2 may be adsorbed onto the hydrophilic adsorbent 100.
Since the second homopolymer HP2 and the third block copolymer BCP3 are hydrophobic in nature, these polymers may only have a weak interaction or even a repulsive interaction with the hydrophilic adsorbent 100. Thus, the second homopolymer HP2 and the third block copolymer BCP3 may not be adsorbed onto the hydrophilic adsorbent 100 and may remain in a dissolved state in the first solvent 110.
The formation of the first mixture solution 140 may be performed by at least one of various methods. In some embodiments, the formation of the first polymer solution 120 of
Referring to
The second homopolymer HP2 and the third block copolymer BCP3 may be precipitated, filtered, and dried to form a first block copolymer composition. The first block copolymer composition may include the second homopolymer HP2 and the third block copolymer BCP3 and may have a composition ratio different from that of the polymers synthesized in
Referring to
Hereinafter, a second purifying process according to example embodiments will be described with reference to
Referring to
Referring to
Referring to
If the volume ratio of the main solvent is higher than 70 vol % in the second solvent 210, the first block copolymer BCP1 may interact more strongly with the second solvent 210 than with the hydrophobic adsorbent 200. In this case, the first block copolymer BCP1 may not be adsorbed onto the hydrophobic adsorbent 200. According to embodiments of the inventive concepts, the volume ratio of the main solvent in the second solvent 210 may be adjusted, and thus, the first block copolymer BCP1 may be adsorbed onto the hydrophobic adsorbent 200.
Since the first homopolymer HP1 is hydrophilic in nature, it may not be adsorbed onto the hydrophobic adsorbent 200. The second block copolymer BCP2 may include the first polymer block P1′ of a high molecular weight and the second polymer block P2′ of a low molecular weight. For example, the molecular weight of the second polymer block P2′ may be less than the molecular weight of the first polymer block P1′ in the second block copolymer BCP2. As such, the interaction between the second polymer block P2′ of the second block copolymer BCP2 and the hydrophobic adsorbent 200 may thus be insufficient to adsorb the second block copolymer BCP2 onto the hydrophobic adsorbent 200. The first homopolymer HP1 and the second block copolymer BCP2 may remain in a dissolved state in the second solvent 210.
The formation of the second mixture solution 240 may be performed by at least one of various methods. In another embodiment, the formation of the second polymer solution 220 of
Referring to
A precipitating process, a filtering process, and a drying process may be performed on the first homopolymer HP1 and the second block copolymer BCP2 to form a third block copolymer composition. A composition ratio of the third block copolymer composition may be different from that of the polymers synthesized in
Referring to
Unlike the embodiment described with reference to
In still another embodiment, one of the first purifying method or the second purifying method may be omitted. In yet another embodiment, the first purifying method or the second purifying method may be performed multiple times, so the first block copolymer BCP1 may become more pure.
It may be difficult to improve the block copolymer BCP1, BCP2, or BCP3 of
A method of forming a pattern according to example embodiments will be described hereinafter.
Referring to
Referring to
Referring to
Referring to
If the phase of the second block copolymer BCP2 is changed, each of the second block portions 335 may have a cylindrical structure or a spherical structure. The weight ratio of the second polymer block P2′ in the second block copolymer BCP2 may be lower than that of the second polymer block P2 in the first block copolymer BCP1. The second polymer blocks P2′ may constitute a cylindrical array including the cylindrical structures regularly arranged, and each of the cylindrical structures may correspond to the second block portion 335. The first polymer blocks P1′ may be formed into a polymer matrix surrounding the second block portions 335 having the cylindrical structures, and the polymer matrix may correspond to the first block portion 333. If the content of the second polymer blocks P2′ is further reduced, the second polymer blocks P2′ may constitute a spherical array including the spherical structures regularly arranged, and the first polymer blocks P1′ may be formed into a polymer matrix surrounding the spherical structures.
If the weight ratio of the first polymer block P1 is reduced, a phenomenon opposite to the above mentioned phenomenon may occur. Thus, if the phase of the third block copolymer BCP3 is changed, each of the first block portions 333 may have a cylindrical shape or a spherical shape.
According to embodiments of the inventive concepts, the kind of the adsorbent and/or the composition ratio of the solvent may be adjusted to control the type of the purified block copolymer to be purified. For example, the second block copolymer BCP2 may be purified with high purity, or the third block copolymer BCP3 may be purified with high purity. The composition of the purified block copolymer BCP1, BCP2, or BCP3 may be controlled to adjust the shapes of the first and second block portions 333 and 335 formed by the block copolymer.
A plurality of block copolymers BCP1, BCP2, and BCP3 may be generally formed by a plurality of polymerizations, respectively. However, according to embodiments of the inventive concepts, the polymer product including a plurality of block copolymer compositions may be formed by the single polymerization described with reference to
Referring again to
Referring to
Referring to
Referring to
Hereinafter, characteristics of the purifying methods and the purified block copolymers according to embodiments of the inventive concepts will be described with reference to experimental examples according to inventive concepts and comparison examples.
Formation of a Block Copolymer Composition and Purification of a Block Copolymer
Methyl methacrylate (MMA) monomers and azobisisobutyronitrile (AIBN) were dissolved in benzene contained in a reactor to form a mixture. The AIBN acts as an initiator and a chain transfer agent. The reactor was then heated at 70° C. for 5 hours to perform the polymerization of the mixture. Styrene monomers were dissolved in benzene to form a styrene solution. The styrene solution was then added to the mixture. The mixture provided with the styrene solution was then heated at 115° C. for 20 hours to perform the polymerization of the styrene and the mixture and thus to form a polymer product. The polymer product was dissolved in dichloromethane, and then an alcoholic solvent was added into the dichloromethane including the polymer product to form a precipitate. Dissolving the precipitate in dichloromethane and adding the alcoholic solvent were alternately repeated to form the as-synthesized polystyrene-block-polymethyl methacrylate.
The first purifying method described with reference to
The silica particles adsorbing the polymer, which remained on the filter paper, were cleaned by an excessive amount of tetrahydrofuran. The cleaned product was concentrated, and the concentrated product was injected into 2 liters of methanol to precipitate the polymer. Cleaning the polymer and precipitating the polymer were alternately repeated. The precipitated polymer was dried in an oven at 50° C. for 3 days, thereby forming the second block copolymer composition.
The second purifying method described with reference to
The C18 silica particles remaining the filter paper and adsorbing the polymer were cleaned using an excessive amount of methylene chloride. The cleaned product was concentrated, and the concentrated product was injected into two liters of methanol to precipitate the copolymer. Cleaning and precipitating the polymer were alternately repeated. The precipitated copolymer was dried in an oven at 50° C. for 3 days to obtain the first block copolymer which was purified.
Method of Forming a Pattern
A block copolymer was coated on a substrate to form a block copolymer layer. Heat was applied to the block copolymer layer to form a first block portion and a second block portion. At this time, the as-synthesized polystyrene-block-polymethylmethacrylate of the comparison example 1 was used as the block copolymer. Shapes and widths of the first and second block portions were measured.
A first portion and a second portion were formed by the same method as the comparison example 2. However, in the present experimental example, the first block copolymer composition formed in the experimental example 1-1 was used as the block copolymer.
A first portion and a second portion were formed by the same method as the comparison example 2. However, in the present experimental example, the second block copolymer composition formed in the experimental example 1-2 was used as the block copolymer.
A first portion and a second portion were formed by the same method as the comparison example 2. However, in the present experimental example, the third block copolymer composition formed in the experimental example 1-3 was used as the block copolymer.
A first portion and a second portion were formed by the same method as the comparison example 2. However, in the present experimental example, the purified first block copolymer obtained in the experimental example 1-4 was used as the block copolymer.
Solubility of Polymers According to Composition of Solvent
A first mixture solution was formed by the same method as the experimental example 1-1. However, in the present comparison example, tetrahydrofuran was used as the first solvent and isooctane was not added. The first mixture solution separated by chromatography (HPLC) and UV absorption at a wavelength of 254 nm was measured of the eluent and analyzed according to a retention time. At this time, a volume ratio of the tetrahydrofuran in the first solvent was increased from 55 vol % to 100 vol % at a rate of 10 vol %/min.
A first mixture solution was formed by the same method as the experimental example 1-1. However, in the present comparison example, tetrahydrofuran of a volume ratio lower than 50 vol % was added into the first solvent. In this case, the polymer product of the comparison example 1 was not dissolved in the tetrahydrofuran, so the first complex was not formed.
A first mixture solution was formed by the same method as the experimental example 1-1. However, in the present experimental example, tetrahydrofuran and isooctane was mixed with each other at a volume ratio of 55:45 to form the first solvent. The first mixture solution was spread on a chromatography to measure a wavelength of 254 nm according to a retention time. At this time, a volume ratio of the tetrahydrofuran in the first solvent was increased from 55 vol % to 100 vol % at a rate of 10 vol %/min.
A second mixture solution was formed by the same method as the experimental example 1-3. However, in the present comparison example, a polymethylmethacrylate homopolymer was used instead of the second block copolymer composition formed in the experimental example 1-2. The second solvent formed by mixing methylene chloride and acetonitrile with each other at a volume ratio of 65:35 was used to form the second mixture solution. The second mixture solution was spread on a chromatography to measure a wavelength of 235 nm according to a retention time. The volume ratio of the methylene chloride was increased to 100 vol % at a rate of 10 vol %/min.
A second mixture solution was formed by the same method as the experimental example 1-3. However, in the present comparison example, a polystyrene homopolymer was used instead of the second block copolymer composition formed in the experimental example 1-2. The second solvent formed by mixing methylene chloride and acetonitrile with each other at a volume ratio of 65:35 was used to form the second mixture solution. The second mixture solution was spread on a chromatography to measure a wavelength of 235 nm according to a retention time. At this time, the volume ratio of the methylene chloride was increased to 100 vol % at a rate of 10 vol %/min.
A second mixture solution was formed using the same method as the comparison example 4-2. However, in the present comparison example, the volume ratio of methylene chloride of the second solvent was lower than 50 vol %. In this case, a polymer product was not dissolved in the methylene chloride, so the second mixture solution was not formed.
A second mixture solution was formed by the same method as the experimental example 1-3. However, in the present experimental example, the polymer product of the comparison example 1 was used instead of the second block copolymer composition formed in the experimental example 1-2. The second solvent formed by mixing methylene chloride and acetonitrile with each other at a volume ratio of 65:35 was used to form the second mixture solution. The second mixture solution was spread on a chromatography to measure a wavelength of 235 nm according to a retention time. At this time, the volume ratio of the methylene chloride was increased to 100 vol % at a rate of 10 vol %/min.
Table 1 shows measurement values of physical/chemical parameters of the block copolymer compositions and the first block copolymer obtained in the comparison example 1 and the experimental examples 1-1 to 1-4.
Referring to Table 1 and
The PDI of the first block copolymer BCP1 purified in the experimental example 1-4 more approaches 1, as compared with the PDIs of the second block copolymer composition of the experimental example 1-2 and the polymer product of the comparison example 1. Since the second purifying process is performed on the first block copolymer BCP1 purified in the experimental example 1-4, the first homopolymer HP1 and the second block copolymer BCP2 may also be removed from the second block copolymer composition of the experimental example 1-2. Thus, the purity of the first block copolymer BCP1 purified in the experimental example 1-4 is higher than those of the polymer product of the comparison example 1, the second block copolymer composition of the experimental example 1-2, and the third block copolymer composition of the experimental example 1-3.
It may be observed that the first block copolymer composition of the experimental example 1-1 has the first block copolymer BCP1 of a relatively low weight ratio. In the experimental example 1-1, it is confirmed that the first block copolymer composition includes a polymer not adsorbed on the hydrophilic adsorbent 100, e.g., the second homopolymer HP2 and the third block copolymer BCP3.
The third block copolymer composition of the experimental example 1-3 may include the second polymer block P2 of the first block copolymer BCP1, which has a relatively high weight ratio. In the experimental example 1-3, it is confirmed that the third block copolymer composition includes a polymer not adsorbed on the hydrophobic adsorbent 200, e.g., the first homopolymer HP1 and the second block copolymer BCP2.
Table 2 shows shapes of patterns formed by the comparison example 2 and the experimental examples 2-1 to 2-4.
Referring to Tables 1 and 2 and
Since the experimental example 1-1 includes the first polymer block P1″ of a relatively low weight ratio, the pattern of the experimental example 2-1 formed using the same may have the cylindrical structure. The first block portions 333 may include the first polymer block P1″ and may constitute the cylindrical-type array. The second block portion 335 may surround the first block portions 333.
Since the experimental example 1-3 includes the first polymer block P1′ of a relatively high weight ratio, the pattern of the experimental example 2-3 formed using the same may have the cylindrical structure. In this case, the second block portions 336 may constitute the cylindrical-type array, and the first block portion 333 may surround the second block portions 335.
Referring to
If the volume ratio of the main solvent in the first solvent is lower than 50 vol % as described in the experimental example 3-2, the first solvent may have low solubility. Thus, the polymer product may not be dissolved in the first solvent.
Referring to
If the volume ratio of the main solvent increases, the peak a3 of the block copolymer may be shown. Here, since polystyrene does not emit light in the wavelength of 254 nm, a peak of the second homopolymer is not observed. The block copolymer may include a hydrophobic polymer, so it may interact with the hydrophobic adsorbent. In the experimental example 3-1, the block copolymer may be adsorbed on the hydrophobic adsorbent in the first solvent. In this case, the peak a3 of the block copolymer may not be shown. If the content of the main solvent increases in the first solvent, the interaction between the block copolymer and the first solvent may increase. If the volume ratio of the main solvent in the first solvent is higher than 70 vol %, the block copolymer may interact more strongly with the first solvent than with the adsorbent. Thus, the block copolymer may be desorbed from the adsorbent. The desorbed block copolymer may be spread on the chromatography, to the peak a3 of the block copolymer may be shown).
According to embodiments of the inventive concepts, the composition ratio of the first solvent may be adjusted to control adsorption and desorption of the block copolymer and the homopolymers.
Referring to
Referring to
Referring to
According to embodiments of the inventive concepts, the composition ratio of the second solvent may be controlled, and thus, the block copolymer and the homopolymers may be adsorbed on or desorbed from the hydrophobic adsorbent.
According to embodiments of the inventive concepts, the synthesized block copolymer may be purified using the hydrophobic adsorbent and the hydrophilic adsorbent. The hydrophobic adsorbent may have adsorbability with respect to the hydrophobic polymer having a molecular weight equal to or greater than a first average molecular weight in the first solvent. The composition ratio of the first solvent may be controlled, so the adsorption and desorption of the hydrophobic polymer may be controlled. The hydrophilic adsorbent may have adsorbability with respect to the hydrophilic polymer having a predetermined molecular weight or more in the second solvent. The composition ratio of the second solvent may be controlled, so the adsorption and desorption of the hydrophilic polymer may be controlled. The homopolymers may be removed from the block copolymer by the purifying method, and thus, the purified block copolymer may have high purity. According to the purifying method, other block copolymers having different composition ratios may be separated from the purified block copolymer, so the purified block copolymer may have higher purity.
According to embodiments of the inventive concepts, a plurality of block copolymer compositions may be separated from a single polymer product by the purifying method. Thus, the block copolymer compositions may be easily formed.
While the inventive concepts have been described with reference to example embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirits and scopes of the inventive concepts. Therefore, it should be understood that the above embodiments are not limiting, but illustrative. Thus, the scopes of the inventive concepts are to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2015-0011324 | Jan 2015 | KR | national |
