阅读说明：本技术 用于分析聚合物膜的方法 (Method for analyzing polymer film ) 是由 柳亨周 具世真 李美宿 尹圣琇 于 2018-07-16 设计创作，主要内容包括：本申请涉及用于分析聚合物膜的方法,所述方法可以通过有效地去除噪声来提高聚合物膜的结构分析的准确性并且缩短分析时间。(The present application relates to a method for analyzing a polymer film, which can improve the accuracy of structural analysis of the polymer film and shorten the analysis time by effectively removing noise.)

1. A method for analyzing a polymer film, comprising a step of blurring an original image of a polymer film having a block copolymer, the polymer film being formed in grooves provided at regular intervals and being self-assembled.

2. The method for analyzing a polymer film according to claim 1, further comprising the step of fourier transforming the raw image and the blurred image.

3. The method for analyzing a polymer film according to claim 2, further comprising the step of removing noise from the image produced by fourier transform.

4. The method for analyzing a polymer film according to claim 3, wherein the step of removing noise is a step of removing an overlapping range of a Fourier transform result of the original image and a Fourier transform result of the blurred image.

5. The method for analyzing a polymer film according to claim 3, further comprising a step of measuring a pitch of a pattern formed on the surface of the polymer film from a Fourier transform result of the original image from which the noise is removed.

6. The method for analyzing a polymer film according to claim 5, wherein the step of measuring a pitch is a step of measuring a peak formed by radially integrating a Fourier transform image of the polymer film in a range of 0 ° to 360 °.

7. The method for analyzing a polymer film according to claim 1, wherein the self-assembled structure of the block copolymer is a columnar structure, a spherical structure, or a layered structure.

8. The method for analyzing a polymer film according to claim 1, wherein the original image of the polymer film is an image obtained by a Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM), or a Transmission Electron Microscope (TEM).

Technical Field

This application claims benefit based on priority of korean patent application No. 10-2017-0089864, filed on 14.7.7.2017, the disclosure of which is incorporated herein by reference in its entirety.

The present application relates to methods for analyzing polymer membranes.

Background

Block copolymers in which two or more chemically different polymer chains are linked by covalent bonds can separate into regular microphases due to their self-assembly properties. The microphase separation phenomenon of such a block copolymer is generally explained by volume fraction, molecular weight, and mutual attraction coefficient between components (flory-harkins interaction parameter), and it can form various structures having a nano-scale sphere, column, helix (gyroid), layer, or the like.

An important issue in the practical application of various nanostructures formed from block copolymers is the control of the orientation of the microphases of the block copolymers. If the spherical block copolymer nanostructure is a zero-dimensional structure without a specific orientation direction, the columnar nanostructure or the layered nanostructure has an orientation as a one-dimensional structure and a two-dimensional structure, respectively. Typical orientation characteristics of block copolymers may include a parallel orientation in which the orientation of the nanostructures is parallel to the substrate direction and a perpendicular orientation in which the orientation of the nanostructures is perpendicular to the substrate direction, with perpendicular orientations generally being of greater importance than parallel orientations.

In general, the orientation of the nanostructures in the film of the block copolymer may be determined by whether any of the blocks of the block copolymer are exposed to a surface or air. That is, the orientation of the nanostructures can be determined by selective wetting of the relevant blocks, wherein since the plurality of substrates are generally polar and air is non-polar, the block of the block copolymer having the greater polarity is wetted on the substrates, while the block having the lesser polarity is wetted at the interface with air, thereby inducing a parallel orientation.

Disclosure of Invention

Technical problem

In order to effectively utilize the self-assembled structure of the block copolymer, it should be possible to first accurately analyze the structure formed by the block copolymer. However, when the structure of the block copolymer is analyzed by imaging, errors due to noise or the like may occur. In particular, when the block copolymer is aligned in the grooves using graphoepitaxy (graphoepitaxy), the line structure of the grooves and the block copolymer are aligned in the same direction, so that there is a problem that many errors occur in the image analysis of the block copolymer structure.

Technical scheme

In the present specification, the term "image" may mean visual information visually recognizable by a human being reproduced and displayed on a two-dimensional or three-dimensional screen, and may mean various visual information such as still images and videos. The still image or video may be a still image or video obtained by using an optical sensor (e.g., a Charge Coupled Device (CCD)) as a semiconductor element and digitally acquiring an image from the subject to the sensor, and may include an image obtained by visually converting a result value measured using an electron microscope or other measuring apparatus, or the like. In addition, the "raw image" may mean an image itself obtained from a sensor or the like, and may mean an image in which a separate post-processing is not performed.

In this specification, "fourier transform" means to transform a pixel value of an image into a value in a frequency domain. Fourier transform is a widely used technique in signal processing, which is based on the following concept: one signal may be represented by a synthesis of several sinusoidal signals and may analyze low frequency components and high frequency components present in the image.

In this specification, "transform" may mean changing the format of data according to a specified algorithm. The transformation may mean changing a position, size, or characteristic by moving an arbitrary object to another position, enlarging, reducing, or rotating the object, or by representing it by changing it from one coordinate system to another, which may be a concept including fourier transformation, image blur, or the like, for example.

The Image, transformation, fourier transformation, and the like may be performed using a known numerical analysis program, an Image processing program, or the like, and the Image may be post-processed using, for example, Image analysis software (national institute of health, [ NIH ] open source, "Image J" or MathWorks, inc., "MATLAB"), or the like.

The present application relates to methods for analyzing polymer membranes. The analysis method of the present application may include a step of blurring an original image of a polymer film having a block copolymer, the polymer film being formed in grooves provided at regular intervals and being self-assembled. A method of obtaining an image of the polymer film is not particularly limited, wherein the image of the polymer film may be digitally acquired using an optical sensor or may be obtained by visually converting a result value measured using an electron microscope or other measuring device, and the image may be obtained, for example, by a Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM), or a Transmission Electron Microscope (TEM).

A method of blurring the obtained image is not particularly limited, and it can be performed by a known method. The blurring process may mean a method of blurring a portion which is an outline of a digital image by removing high frequency components (those having a large pixel value change rate) of the digital image or removing extreme values from pixel values and assigning a result value averaged with adjacent pixels. The blurring process may use various known blurring methods without limitation as long as it can impart an image blurring effect, and for example, a method such as low-pass filtering, gaussian blurring, motion blurring, or radial blurring may be used. By blurring the image of the polymer film to separate the region corresponding to the trench and the region corresponding to the self-assembled block copolymer from the original image of the polymer film, accurate analysis of the image of the polymer film can be achieved. As a method of blurring the Image, a known Image processing program or the like may be used, and for example, the obtained Image may be fourier-transformed using Image analysis software (national institute of health [ NIH ] open source, "Image J" or MathWorks, inc., "MATLAB") or the like.

In one example of the present application, it may further include the step of fourier transforming the obtained original image and blurred image. The method of fourier-transforming the obtained original image and blurred image is not particularly limited, and it may be performed by a known method. As a method of fourier-transforming the Image, a known Image processing program or the like may be used, and for example, the obtained Image may be fourier-transformed using Image analysis software (national institute of health [ NIH ] open source, "Image J" or MathWorks, inc., "MATLAB") or the like.

When the obtained image is fourier-transformed, a fourier-transformed image can be obtained. The fourier transform image shows the result of transforming the pixel values of the image into frequency domain values. In general, a low frequency region of a fourier transform image represents information on the overall brightness of the image, and a high frequency region represents information on edges or noise of the image. By the fourier transform, only information on noise components included in an image of the polymer film can be separated and removed, thereby reducing errors in analyzing the polymer film. By performing fourier transform on the blurred image, the difference between the portion on the substrate where the polymer film is formed and the portion on the substrate where the polymer film is not formed can be made clear, so that in the analysis of the polymer film, it is possible to perform analysis only on the portion on which the polymer film is formed.

In one example, a method for analyzing a polymer film according to the present application may further include a step of removing noise from an image generated by fourier transform. Noise can be removed from the fourier transform image, thereby reducing errors in analyzing the polymer film. The step of removing noise may be a step of removing an overlapping range of a fourier transform result of the original image and a fourier transform result of the blurred image. By removing, from the result of fourier transforming the original image, a range overlapping with the result of fourier transforming the image subjected to fourier transform after the blurring process, only a region corresponding to noise other than the polymer film can be removed and only a region of information on the polymer film can be acquired. A method of removing a range overlapping with a result of fourier transforming the image subjected to fourier transform after the blurring process from a result of fourier transforming the original image is not particularly limited, and it may be performed, for example, using known image analysis software or the like.

The method for analyzing a polymer film of the present application may comprise the steps of: the pitch of the pattern formed on the surface of the polymer film was measured from the fourier transform result of the original image from which the noise was removed. The pattern may mean a shape formed due to a self-assembled structure of a block copolymer to be described below, and may mean a pattern including two or more lines. By measuring the pitch of the pattern from the fourier transform image, the self-assembled structure of the polymer film can be accurately analyzed.

In one example of the present application, the pitch of the pattern formed on the surface of the polymer film may be measured by converting a two-dimensional spectral image formed by fourier transform into a one-dimensional map via radial integration. If the fourier transform two-dimensional image is radially integrated in the range of 0 ° to 360 °, a one-dimensional graph representing the frequency density can be obtained, wherein the X-coordinate value of the first peak on the frequency domain graph can mean the pitch of the actual region of the pattern formed on the surface of the polymer film. By measuring the pitch of the pattern formed on the surface of the polymer film using the peak value, the structure of the polymer film can be accurately analyzed.

The polymer film of the present application may be formed on a substrate having a trench formed thereon. The type of substrate applied to the method of the present application is not particularly limited. As the substrate, for example, various types of substrates which are required to form a pattern on a surface may all be used for application of the above-described respective applications. This type of substrate may include semiconductor substrates such as silicon substrates, silicon germanium substrates, GaAs substrates, and silicon oxide substrates. As the substrate, for example, a substrate applied to form a finFET (fin field effect transistor) or other electronic devices such as a diode, a transistor, or a capacitor 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 may be applied in the present application is not limited thereto.

Mesas may be formed on a surface of a substrate applied to the method of the present application, spaced apart from each other, and a trench may be formed through the mesas. For example, the mesa structures may each be in the form of a line. Such mesa structures may be spaced apart from each other at regular intervals and disposed on the substrate surface. The mesa structures may be disposed substantially parallel to each other on the surface of the substrate. At least two or more mesa structures may be formed on a 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 mesas and trenches is not particularly limited and may be adjusted according to the application.

The ratio (D/H) of the distance (D) of the mesa structures spaced apart to form the trench to the height (H) of the mesa structures is not particularly limited, and may be, for example, 0.1 or more and may be 10 or less. In addition, the ratio (D/W) of the distance (D) between the mesa structures to the width (W) of the mesa structures is not particularly limited, and may be 0.5 or more and may be 10 or less. The ratio (D/H or D/W) may vary depending on the intended use. In the present specification, the term distance (D) of the mesa structures means the shortest distance between spaced apart adjacent mesa structures, wherein the distance (D) may be, for example, 5nm or more and may be 500nm or less. In the present specification, the term height (H) of the mesa structure is based on a dimension of the mesa structure measured in an upward direction along a normal direction of the surface of the substrate, which may be, for example, 1nm or more and may be 100nm or less. In the present specification, the term width (W) of the mesa structure is a dimension of the mesa structure measured in a direction perpendicular to a normal direction of the substrate surface, which may be, for example, 5nm or more and may be 500nm or less. For example, when the block copolymer is applied as the self-assembly inducing material and a layered pattern of the block copolymer is formed, the distance of the mesa structure may be in the range of about 1L to 20L. In this case, the film including the block copolymer, i.e., the film formed in the trench may have a thickness in a range of about 0.1L to 10L, or 1L to 8L. The dimensions of the mesa structures, etc. are one example of the present application and may vary depending on the particular aspect.

A method of forming such a mesa structure on a substrate is not particularly limited, and a known method may be applied thereto. For example, the mesa structure may be formed by etching the substrate in a suitable manner or by depositing a suitable material on the substrate.

Here, the kind of the mesa structure-forming material is not particularly limited. For example, as the material, a material which can be etched by an etching process to form a mesa structure may be used. For example, as the material, SiO may be applied ₂ACL (amorphous carbon layer), SOG (spin on glass), SOC (spin on carbon), silicon nitride, or the like. The layer of such a material may be applied by a method such as spin coating, or may be formed by a vapor deposition method such as CVD (chemical vapor deposition). When the layer of the material is formed, the thickness thereof and the like are not particularly limited, and the layer may be formed to have an appropriate thickness in consideration of the height (H) of the desired mesa structure.

In one example of the present application, the polymer film may include a block copolymer. The block copolymer may be a block copolymer having a first block and a second block chemically different from the first block. A block copolymer may mean a molecular structure in which polymer blocks having different chemical structures are linked by covalent bonds.

The block copolymer may form a self-assembled structure. The self-assembled structure may mean that a specific structure is formed by interaction between respective blocks included in the block copolymer. The self-assembled structure of the block copolymer may be a spherical structure, a columnar structure or a layered structure. In one example, in the case of a spherical structure or a layered structure, the block copolymer may exist in a vertically oriented state. For example, within a segment of the first block or the second block or other block covalently bonded thereto in the block copolymer, the other segment may be vertically oriented while forming a regular structure such as a lamellar shape or a columnar shape. The block copolymer that may be included in the polymer film of the present application is not particularly limited.

The block copolymer of the present application may be a diblock copolymer comprising a first block and a second block as described above, or may be a multiblock copolymer comprising one or more of two or more first blocks and second blocks or comprising a different type of third block.

The method of forming such a polymer film using the block copolymer is not particularly limited. For example, the method of forming the polymer film may include the following processes: a layer of a block copolymer or a coating solution obtained by diluting it in an appropriate solvent is formed on the neutral layer by coating or the like, and the layer is aged or heat-treated, if necessary.

Aging or heat treatment may be based on, for example, the phase transition temperature or glass transition temperature of the block copolymer, and may be performed, for example, at a temperature higher than the glass transition temperature or phase transition temperature. The time for performing this heat treatment is not particularly limited, and it may be performed, for example, in the range of about 1 minute to 72 hours, but this may be changed as needed. In addition, the heat treatment temperature of the polymer film may be, for example, about 100 ℃ to 250 ℃, but this may be changed in consideration of the block copolymer to be used. In another example, the formed layer solvent may also be aged in a non-polar solvent and/or a polar solvent at room temperature for about 1 minute to 72 hours.

Advantageous effects

The method for analyzing a polymer film of the present application can improve the accuracy of structural analysis of the polymer film and shorten the analysis time by effectively removing noise.

Drawings

Fig. 1 is an SEM photograph of a polymer film including a block copolymer formed in a trench.

Fig. 2 is an image obtained by fourier transforming the image of fig. 1.

Fig. 3 is an image obtained by blurring the image of fig. 1.

Fig. 4 is an image obtained by fourier transforming the image of fig. 3.

Fig. 5 is an image in which an area overlapping with fig. 4 is removed from fig. 2.

Fig. 6 is a result of integrating the image of fig. 5.

Fig. 7 is a result of integrating the image of fig. 2.

Fig. 8 is an SEM photograph of a polymer film including a block copolymer formed in a trench.

Fig. 9 is an image obtained by fourier transforming the image of fig. 8.

Fig. 10 is an image obtained by blurring the image of fig. 8.

Fig. 11 is an image obtained by fourier transforming the image of fig. 10.

Fig. 12 is an image in which an area overlapping with fig. 11 is removed from fig. 9.

Fig. 13 is a result of integrating the image of fig. 12.

Fig. 14 is a result of integrating the image of fig. 9.

Detailed Description

Hereinafter, the present application will be described in more 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.