KR101412228B1 - Method for manufacturing thin film comprising mixed block copolymer, method for manufacturing template comprising mixed block copolymer, and thin film and template mixed block copolymer - Google Patents

Abstract

A mixed block copolymer thin film preparation method, a mixed block copolymer mold production method, and a mixed block copolymer thin film and a mold prepared thereby are provided.
The method for producing a mixed block copolymer thin film according to the present invention is a method for producing a mixed block copolymer thin film which has a high molecular weight and a long chain length and has a self-assembled first block copolymer and a second block copolymer having a low molecular weight, Block copolymer to prepare a mixed solution; Laminating the mixed solution on a substrate to form a block copolymer thin film; And self-assembling the formed block copolymer thin film by heat treatment.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for preparing a mixed block copolymer thin film, a method for producing a mixed block copolymer, a mixed block copolymer prepared by the method, and template mixed block copolymer}

The present invention relates to a process for producing a mixed block copolymer thin film, a process for producing a mixed block copolymer template, and a mixed block copolymer thin film and a template prepared thereby, and more particularly, to a process for producing a mixed block copolymer, The present invention also relates to a method for producing a mixed block copolymer thin film and a mixed block copolymer thin film and a mold prepared thereby.

Block copolymers are self-assembled macromolecular materials in which chemically distinct macromolecular blocks are covalently bonded. Through the micro-separation of each of the non-dissolved blocks, periodically repeated mosquitos, cylinders or plate-like arrays are formed, the size of which can be adjusted in the range of 3-50 nm. Thus, for the purposes of nanostructure templating and nanorisography as an alternative to conventional lithography, the block copolymers have been actively studied. However, in order to apply the block copolymer thin film to practical device manufacture, it is necessary to solve difficulties such as, for example, precise control of the size and period of the fine region, improvement in alignment, and reduction in defect level.

The microdomain size in the form of a microstructure of the block copolymer thin film and its repetition period can be determined by changing the length and relative composition of each block. Block copolymer chemical synthesis of different lengths is limited by very precise, difficult processes. Therefore, new alternatives to such chemical synthesis are required.

Previously, a method of precisely adjusting the plate structure in bulk films by applying an electric field has been reported, where the spacing between plates is reduced to about 6%. In addition, mixing at the molecular level can be studied to control the microstructure size of the block copolymer thin film. A mixture of polystyrene (PS) or poly (methyl methacrylate) (PMMA) homopolymer with a polystyrene block-poly (methyl methacrylate) (PS-b-PMMA) of symmetry, PS- The diblock copolymer was analyzed with neutral reflectance. In this case, the homopolymer is more limited to the lamellar fine region as the molecular weight of the homopolymer increases. Recently, active research on this field is under way. The addition of the homopolymer can be studied as an alternative to improve the size level of the microdomain that can be achieved with a simple block copolymer to control the period and domain size of vertically aligned cylinders. However, the addition of a large amount of the homopolymer causes undesired results such as formation of an uneven block copolymer structure, and further, there is a problem of causing undesired loss in phase separation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a block copolymer-based thin film for solving the problems of the prior art described above.

In order to solve the above-mentioned problems, the present invention provides a first block copolymer having a high molecular weight and a long chain length, a second block copolymer having a low molecular weight and a short length, Mixing the coalescents to produce a mixture; Laminating the mixture on a substrate to form a block copolymer thin film; And a step of self-assembling the formed block copolymer thin film by heat treatment to form a mixed block copolymer thin film.

In one embodiment of the present invention, in accordance with the self-assembling step, some of the block polymers of the first block copolymer are self-assembled into a cylinder or plate-like structure.

In one embodiment of the present invention, the second block copolymer has a molecular weight and a chain length at a level that is not self-assembled in the self-assembling step.

In one embodiment of the present invention, the second block copolymer is mixed with 10 to 50% by weight of the block copolymer thin film.

In one embodiment of the present invention, the first block copolymer and the second block copolymer are the same type of diblock copolymer.

In one embodiment of the present invention, the first block copolymer and the second block copolymer are polystyrene-block-polymethacrylate copolymers.

In order to solve the above-mentioned problems, the present invention provides a mixed block copolymer thin film produced by the above-described method.

In order to solve the above-mentioned problem, the present invention provides a method for producing a block copolymer having a high molecular weight and a long chain length and a self-assembled first block copolymer having a low molecular weight, Mixing the block copolymer to prepare a mixture; Laminating the mixture on a substrate to form a block copolymer thin film; Subjecting the formed block copolymer thin film to heat treatment to self-assemble in a plate or cylinder shape; And selectively etching the self-assembled block copolymer to form a plate-like or cylinder-shaped pattern.

In one embodiment of the present invention, the second block copolymer has a molecular weight and a chain length at a level that is not self-assembled in the self-assembling step.

In one embodiment of the present invention, the second block copolymer is mixed with 10 to 50% by weight of the block copolymer thin film.

In one embodiment of the present invention, as the second block copolymer content increases, the repetition period between the plate-like or cylinder patterns is shortened.

In one embodiment of the present invention, as the second block copolymer content increases, the distance between the centers of the cylinders becomes shorter.

In order to solve the above-mentioned problems, the present invention provides a block copolymer mold produced by the above-mentioned method.

In one embodiment of the present invention, the block copolymer template has a plate or cylinder pattern, and the pattern is oriented in a predetermined direction by the second block copolymer.

According to another aspect of the present invention, there is provided a method for producing a block copolymer, comprising the steps of: preparing a block copolymer template on a substrate by the method according to any one of claims 8 to 12; Laminating a metal material on the block copolymer template; And removing the block copolymer template to produce nanoparticles of the metal material on the substrate.

According to the present invention, a high molecular weight block copolymer (first block copolymer) having a long chain length and a low molecular weight block polymer (second block copolymer) having a shorter chain length than the one block copolymer and having symmetry To provide a blend block copolymer thin film. As a result, the orientation properties and defect reduction characteristics of the mixed block copolymer are improved, and the size and dimensions can be controlled.

Figure 1 shows a schematic cross-sectional view of a symmetric PS-b-PMMA diblock copolymer (second block copolymer) of a 5k-5k short length having a length of 48k-46k symmetry or a length of 140k-60k asymmetric diblock copolymer Assembled nanostructure by mixing the nanostructure with the nanostructure.
2 is a scanning electron microscope (SEM) image of a mixed structure according to PS-b-PMMA or 5k-5k PS-b-PMMA composition ratios of a 48-46 k plate structure and a 140-60 k cylinder structure.
FIG. 3 is a view showing the size and cycle of the nanostructure shown in FIG. 2, showing the relationship between the fine region size and the period and the content of 5k-5k PS-b-PMMA.
Figure 4 is a diagram illustrating the measurement and analysis of defect density as a function of the 5k-5k PS-b-PMMA content to quantify the relative properties and dimensions of the structures according to each embodiment.
FIG. 5 is an SEM image of a topographic photoresist pattern produced by a mixed block copolymer thin film produced according to the present invention.
Figure 6 is an image of a gold nanoparticle array replicating a patterned block copolymer mold morphology.
FIG. 7 is a graph of the gold nanoparticle array fabricated in FIG. 6 using UV-Vis absorption spectroscopy.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a double-block copolymer film according to each embodiment of the present invention, a method for producing the same, and the like will be described with reference to the accompanying drawings.

The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention. Accordingly, equivalent inventions performing the same functions as the present invention are also within the scope of the present invention.

In addition, in adding reference numerals to the constituent elements of the drawings, it is to be noted that the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

Disclosure of the Invention In order to solve the above problems of the prior art, the present invention provides a high molecular weight block copolymer having a long chain length (first block copolymer) and a low molecular weight block polymer having a shorter chain length than the one block copolymer The present inventors have found that such a second block copolymer is composed of two block polymers, and the two block copolymers have the same molecular weight (i.e., Of the present invention, it has been found that the orientation properties, defective reduction properties, and the like of the mixed block copolymer are improved when they have so-called symmetry.

Hereinafter, the present invention will be described as an example using PS-b-PMMA as a block copolymer, but the scope of the present invention is not limited thereto.

One embodiment of the present invention is a method for producing a PS-b-PMMA diblock copolymer having a high molecular weight long chain length PS-b-PMMA and a symmetric short chain length PS-b-PMMA diblock copolymer mixed solution, Is provided. Thus, it is possible to control the microdomain size and the repetition period of the self-assembled block copolymer nanostructure to be purified, and in particular, the size dimension is changed according to the composition ratio of the short-length PS-b-PMMA. That is, as the short length composition is increased, the defect density of the thin film mixture is reduced, which makes it easier to align the nanostructure even in a wide trench wall.

Experimental Example

matter

Polystyrene block-polymethyl methacrylate (PS-b-PMMA, Mn = 5-5 kg mol ^-1 , 48-46 kg mol ^-1 , 140-60 kg mol ^-1 was purchased, The evaporation source was purchased from Tasco.

Self-assembly of block copolymer in pure or mixed film

The silicon substrate was immersed in pinna solution (sulfuric acid: hydrogen peroxide 7: 3 mixture) for 1 hour at 110 degrees Celsius, washed several times with deionized water, and washed. After cleaning, the silicon surface was washed several times with a uniform neutral blush. A mixed blend of PS-b-PMMA (48-46k or 140-60k, first polymer) with a single block copolymer film (comparative) and PS-b-PMMA (5k-5k, second polymer) The film was spin-coated with a Toluene solution and then annealed at a vacuum of 190 degrees Celsius for 2 hours to produce a self-assembled structure of nano-sized morphology consisting of a plate or cylinder array.

Photoresist trench manufacturing

Topographic photoresist confinement was prepared using SU-8 negative tone photoresist (MicroChem Corp. USA). A 180 nm thick photoresist layer was spin coated onto the cleaned silicon substrate and soft baked at 65 degrees Celsius for 20 seconds. An I-line source (Midas / MDA-6000 DUV, KR; wavelength 365 nm; 9.5 mW / cm 2) was passed through the patterned mask and irradiated to the photoresist film to expose. Then, after baking at 110 degrees Celsius for 60 seconds, the exposed portions of the film were selectively crosslinked. Thereafter, the film was immersed in propylene glycol methyl ether acetate (PGMEA) solution for 60 seconds to conduct pattern development.

Gold array production

The BC0 or BC3 block copolymer film was irradiated with UV, followed by washing with acetic acid and water to optionally remove the PMMA cylinder core and crosslink the remaining PS matrix. After the mold was prepared, a gold film was deposited on the hexagonal nanopore block copolymer mold. After metal deposition, residual PS nanopore molds were removed by lift-off treatment in toluene with ultrasonic waves. A gold nanoparticle array replicating the block copolymer mold morphology was fabricated on a transparent Pyrex glass substrate.

Character analysis

Nano-sized morphology of block copolymer thin films and gold nanoparticle arrays were always analyzed using Hitachi S-4800 SEM. The UV-vis absorption spectra of the gold nanoparticle arrays were measured using a UV-3101 PC spectrophotometer.

Mixed block copolymer film production

The symmetric or asymmetric PS-b-PMMA thin film is self-assembled to form fine regions of a plate-like or cylindrical surface vertical structure on the neutral surface. In a single block copolymer, the size and period of the nano-domains are determined by the molecular weight of each block. Short-length PS-b-PMMA can be mixed into the original PS-b-PMMA instead of chemical synthesis, treatment to adjust the size of the desired nano-domains.

Figure 1 shows a schematic cross-sectional view of a symmetric PS-b-PMMA diblock copolymer (second block copolymer) of a 5k-5k short length having a length of 48k-46k symmetry or a length of 140k-60k asymmetric diblock copolymer Assembled nanostructure by mixing the nanostructure with the nanostructure.

Referring to FIG. 1, it can be seen that the size of the final formed mixture is reduced by mixing short-length 5 k-5k PS-b-PMMA having symmetry with a long-length symmetric or asymmetric block copolymer. In Fig. 1, PL is a plate-to-plate interval, PBL is a mixed plate-like cycle, PC is a cylinder cycle, PBC is a mixed cylinder cycle, DC is a cylinder cycle, and DBC is a mixed cylinder cycle.

The results of FIG. 1 show that the long length diblock copolymer has a strong separation region, but the 10k copolymer has a weak separation region due to the bulk PS-b-PMMA interaction parameter (0.037 χ). Compared with a single PS-b-PMMA thin film, a mixture of short-length diblock copolymers shows a decrease in plate or cylinder area size.

2 is a scanning electron microscope (SEM) image of a mixed structure according to PS-b-PMMA or 5k-5k PS-b-PMMA composition ratios of a 48-46 k plate structure and a 140-60 k cylinder structure.

2, the first letter means a mixture, the second letter means plate (L) or cylinder phase (C), the third number means 5k-5k PS-b-PMMA mixture %to be. For example, BC3 means 70 wt% 140k-60k PS-b-PMMA and 30 wt% 5k-5k PS-b-PMMA.

Referring to FIG. 2, it can be seen that the plate-shaped or cylinder-structured block copolymer thin film has a plate structure having a fine region size and a period of 48 nm, and a cylinder structure having a diameter of 40 nm and a center distance of 80 nm have.

However, it can be seen that the period of the plate-like structure decreases as the content of 5k-5k PS-b-PMMA increases. As the content of added 5k-5k PS-b-PMMA increased from 0 to 50%, the period of the plate structure decreased from ~ 48.1 nm to ~ 35 nm.

In the case of the cylinder structure, similar behavior occurred and was observed. As the content of added 5k-5k PS-b-PMMA increased from 0 to 50%, the cylinder structure period decreased from ~ 78 nm to ~ 52.5 nm, and the cylinder structure size also decreased from 43.8 nm to 31.5 nm. In addition, as the content of 5k-5k PS-b-PMMA exceeded 50% (BL6 and BC6), heterogeneous and large phase separation occurred. Therefore, the content of 5k-5k PS-b-PMMA according to the present invention is preferably 0 to 50% by weight.

The position of the short-length diblock copolymer in the self-assembled thin film is determined by the content of the short-length diblock copolymer. As the short-length diblock copolymer having symmetry is mixed, the short-length diblock copolymer separates at the interface of the different block bodies and behaves as a compatibilizer. On the contrary, when the block copolymer is mixed with a high degree of asymmetry, most of the short-length block copolymers are located in the fine region and behave like the homopolymer filler. Thus, the nanostructures obtained with diblock copolymers exhibit reduced size and nano-domain cycles, which is due to the position of short-length diblock copolymers located at the interface between the different blocks.

FIG. 3 is a view showing the size and cycle of the nanostructure shown in FIG. 2, showing the relationship between the microdomain size, the period, and the content of 5k-5k PS-b-PMMA. 27% in the case of lamellar nanotubes and 32% in the case of cylindrical nanostructures. Through these properties, it is possible to effectively and precisely control the size and distance of the fine region of the block copolymer mixture.

In order to quantify the relative properties and dimensions of the structures according to each example, the defect density was measured and analyzed as a function of 5k-5k PS-b-PMMA content and is shown in Fig. Defects can be expressed as dislocation or disclination in a plate-like nanostructure, and in the case of a cylinder structure, if there are five or seven adjacent structures, the defect can be measured as a defect.

It was observed that as the 5k-5k PS-b-PMMA was added, the defect density was significantly reduced. This is also demonstrated by the fact that ordered, homogeneous nano-domains have improved polydispersity and are formed in mixed films.

Since the fine phase separation in the block copolymer film on the non-patterned surface forms an arbitrarily oriented fine region, a chemical or topographic pattern is used to improve the orientation to the direction. For directional assembly of block copolymers, a topographic photoresist structure constraint (100 nm wide, 180 nm high) was prepared using SU-8, a negative tone photoresist. The thin film of the single or mixed block copolymer was spin-coated from the toluene solution onto the topographic pattern, followed by thermal annealing.

Both the plate or cylinder structures were induced to have aligned orientation on the topographic pattern walls with the addition of 5k-5k PS-b-PMMA. In unmixed films, nano-regions of plate or cylinder structure did not exhibit this alignment structure (Figures 5a, 5e). However, with the addition of 5k-5k PS-b-PMMA, the lateral ordering of the microdomains was remarkably improved, and the FFT (Fast Fourier transforms) also demonstrated a considerable improvement of the lateral order (inserted image of FIG. 5)

As described above, the mixed thin film to which the short-length block copolymer is added according to the present invention has a more uniform, dense, and oriented order as compared with the single-block copolymer. Such excellent properties of the mixed film according to the present invention were confirmed by pattern transfer. The BC0 and BC3 films were irradiated with UV, followed by washing with acetic acid to selectively remove the PMMA core. Thereafter, a 20 nm thick gold film was laminated on the hexagonal nanopore block copolymer mold, and the remaining PS nanopore mold was removed by a lift-off process using ultrasonic waves. As a result, a gold nanoparticle array replicating the patterned block copolymer mold morphology was present on the transparent glass substrate (see FIG. 6). The gold nanoparticle arrays from BC0 and BC3 were confirmed using a UV-Vis absorption spectroscope (see FIG. 7).

Referring to FIGS. 6 and 7, gold nanoparticle arrays from BC0 exhibit weak and broad absorption bands in the visible light region, but are produced from BC3, and uniform and dense gold arrays exhibit strong and narrow absorption bands.

As described above, the mixed thin film of the present invention produced by mixing a high molecular weight long chain length PS-b-PMMA and a low molecular weight short chain length PS-b-PMMA having symmetry can control the fine region size and cycle Provides a possible effect. In addition, the microdomain size and cycle are reduced with such a symmetrical short-length diblock copolymer blend, and furthermore, the defects are also reduced by the mixing of the low-molecular-weight short-length diblock copolymer, The orientation characteristics of the nanostructure can be obtained. This makes it possible to arrange a uniform, dense, and uniformly oriented nanostructure array in the trench wall.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (15)

Mixing the first block copolymer with a second block copolymer having a lower molecular weight than that of the first block copolymer and having a shorter chain length than the first block copolymer to prepare a mixture;
Laminating the mixture on a substrate to form a block copolymer thin film; And
Wherein the second block copolymer has a molecular weight and a chain length that are not self-assembled in the self-assembling step, Thin film manufacturing method. The method according to claim 1,
Wherein the first block copolymer is self-assembled into a cylinder or a plate structure according to the self-assembling step.
delete The method according to claim 1,
Wherein the second block copolymer is mixed at 10 to 50 wt% of the block copolymer thin film.
The method according to claim 1,
Wherein the first block copolymer and the second block copolymer are the same type of diblock copolymer.
6. The method of claim 5,
Wherein the first block copolymer and the second block copolymer are polystyrene-block-polymethacrylate copolymers.
A mixed block copolymer thin film produced by the method according to any one of claims 1, 2 and 4 to 6.
Mixing the first block copolymer with a second block copolymer having a lower molecular weight than that of the first block copolymer and having a shorter chain length than the first block copolymer to prepare a mixture;
Laminating the mixture on a substrate to form a block copolymer thin film;
Subjecting the formed block copolymer thin film to heat treatment to self-assemble in a plate or cylinder shape; And
And a step of selectively etching the self-assembled block copolymer to form a plate-like or cylinder-shaped pattern, wherein the second block copolymer has a level of self-assembling A molecular weight and a chain length of the block copolymer. delete 9. The method of claim 8,
Wherein the second block copolymer is mixed at 10 to 50 wt% of the block copolymer thin film. 9. The method of claim 8,
Wherein the repetition period between the plate-like or cylinder patterns is shortened as the second block copolymer content is increased.
9. The method of claim 8,
Wherein the center-to-center distance of the cylinder is shortened as the second block copolymer content is increased.
A block copolymer mold produced by the process according to any one of claims 8, 10 or 12.
14. The method of claim 13,
Wherein the block copolymer template has a plate or cylinder pattern, and the pattern is oriented in a predetermined direction by the second block copolymer.
Producing a block copolymer template on the substrate by the process according to any one of claims 8 to 12;
Laminating a metal material on the block copolymer template; And
And removing the block copolymer template to produce nanoparticles of the metal material on the substrate.

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