KR20000067676A - Film of abc triblock copolymer whose cylindrical structure is coated vertically and method thereof - Google Patents

Abstract

PURPOSE: An ABC triple block copolymer thin film and method for the preparation thereof by forming an ABC triple block copolymer on the substrate such as silicon or silicon oxide in a proper condition and then a cylinder type structure of the copolymer to make it perpendicular to the substrate are provided which can be used for nano structure forming technique and semiconductor capacitors. CONSTITUTION: An ABC triple block copolymer thin film is obtained by coating an ABC triple block copolymer comprising a B polymer selected to satisfy the following condition; the following formulae in which ψA, ψB represent each a volume fraction of A and B elements, γAB, γBC represent each a surface tension£dynes/m¬2| acting between A-B and B-C blocks and γAS, γBS, γCS represent each a surface tension£dynes/m¬2| acting between A, B, C blocks.

Description

Thin film of ACC triblock copolymer coated with cylinder structure vertically and its manufacturing method {FILM OF ABC TRIBLOCK COPOLYMER WHOSE CYLINDRICAL STRUCTURE IS COATED VERTICALLY AND METHOD THEREOF}

The present invention relates to a thin film of the ABC triblock copolymer and a method of manufacturing the same, and more particularly to a thin film of the ABC triblock copolymer coated with a vertical structure of the cylinder structure of the ABC triblock copolymer and a method for producing the same. .

Efforts have already been made to make nanostructures using AB block double block copolymers or ABA type triple block copolymers and use them as masks.

It is well known that when two or more kinds of polymer materials are mixed, the entire system undergoes phase separation to minimize free energy, and this phase separation also occurs in block copolymers (Science, 251, 898 (1991)). ). However, in a block copolymer, since two or more kinds of substances are connected to each other in a chain, they do not completely split into two phases, and according to the composition of one substance, structures such as spheres, cylinders, and membranes Will be generated.

On the other hand, it is known that the regular structure appears the same when the polymer is coated with a thin film on the substrate, but there is a difference in whether the structure occurs vertically or horizontally with the underlying substrate. In particular, the polymer having a cylindrical shape is vertically coated on a substrate, and one of the two materials may be selectively removed by etching such as ozone to use it as a mask for a semiconductor, which will be described with reference to FIG. 1. Is as follows.

Figure 1 schematically shows a process of forming a nanostructure using a block copolymer as a mask in the prior art. Spin coating and then annealing the polymer solution 12 containing the A polymer and the B polymer on the substrate 11 forms a thin film formed on the substrate as shown in the second step of FIG. It will have a cross section in which the B block 14 is formed. In the thin film manufacturing process shown in Figure 1, A block made of A polymer and B block made of B polymer are formed to be perpendicular to the substrate in the form of a cylinder structure. A pattern is formed on the A block 3 and the B block 4 by ozone etching, reactive ion etching, or chemical etching, respectively. Finally, the substrate having the pattern formed is immersed in a toluene solution to completely remove the remaining polymer to form a hole structure.

As described above, in the case of a substrate in which the cylinder structure is formed vertically, since the diameter of the cylinder is usually several tens of nm and the distance between the cylinders is several tens of nm, even a microstructure inaccessible by conventional photolithography can be easily obtained. There is an advantage that can be obtained. It has already been attempted by Mansky et al. (Appl. Phys. Lett. 68 2586 (1996)), and recently, these copolymer shapes have been applied to the substrate using the same RIE method as in the process of FIG. ^It has been reported that ¹¹ holes / cm ² structures have been successfully formed (Science, 276, 1401 (1997)).

However, in the above process, when a block copolymer of the conventional AB type or ABA type is used, the thickness of the thin film is not easily controlled by forming a block formed in a horizontal structure on the substrate at a specific thickness or more. Cost effectiveness has been pointed out as a limitation for many applications.

The present invention has been made to improve the above-described problems, ABC triblock copolymer is always coated in a vertical structure regardless of the thickness of the thin film through the selection of the B polymer satisfying a certain condition among the ABC triblock copolymer An object of the present invention is to provide a thin film and a method for producing the same.

1 is a schematic diagram showing a nanostructure manufacturing process using the AB block polymer according to the prior art as a mask

Figure 2 is a perspective view of the ABC triple block copolymer thin film prepared according to the present invention

<Description of Main Parts of Drawing>

1: distance between two cylinders 2: radius of cylinder

3: substrate 11: substrate

12: polymer solution 13: A block

14: B block 15: Melted A block

16: melted B block 17: hole

The triblock copolymer of the present invention as described above will be described in more detail with reference to the accompanying drawings for producing a thin film coated with a vertical structure.

Figure 2 is a perspective view of the ABC triblock copolymer thin film prepared according to the present invention, showing that the ABC triblock copolymer coated with a thin film on a silicon substrate. The present invention is to select the B polymer that satisfies a certain condition among the A, B and C polymer to coat the ABC triblock copolymer in a vertical structure on the substrate, wherein the vertical structure formed is then one or two of the ABC polymer block By selectively etching the polymer block can be used as a mask for a semiconductor. In order to use the ABC triple block copolymer of the present invention as a mask for a semiconductor, the process illustrated in FIG. 1 may be used.

In the method of manufacturing a thin film in which the cylinder structure of the ABC triblock copolymer of the present invention is vertically coated, theoretically, under what conditions, when the block copolymer is coated as a thin film on a substrate, under what conditions the cylinder occurs in a vertical structure or a horizontal structure Derived through the equation as follows.

When the block copolymer is coated on the substrate, the total energy that determines the structure is the conformation energy due to the lattice being out of equilibrium, the interfacial energy between the interface of the copolymer, and the substrate and the atmosphere. It can be thought of as the sum of surface energy due to the influence of.

The results published in the literature (J. chem. Phys. 108 1253 (1993)) can be extended to ABC triple block copolymers to theoretically derive the conditions that the vertical structure takes precedence.

In this case, the dimensionless group is defined as follows;

, , , ,

The meaning of each character is as follows.

: Volume fraction of A and B elements

: Interfacial tension acting between AB and BC blocks ([dynes / nm ² ])

: Surface tension acting between A, B, C block and substrate ([dynes / nm ² ])

: Contact area per copolymer chain ([nm ² / chain])

= Degree of polymerization

: Density ([# of chain / nm ² ])

: Distance between two cylinders ([nm])

= Distance between two cylinders in equilibrium ([nm])

: Boltzmann constant ([J / K])

: Absolute temperature ([K])

Where I and J are constants given by volume fraction and physical properties (J. chem. Phys. 108 1253 (1993)). In order to reduce the number of variables, a confined system in which substrates are formed above and below the thin film is considered.

In Equation 1, if the last term is 0 or less, it can be concluded that only a vertical structure can always be obtained, and consequently, the condition of B polymer that can always obtain a vertical structure is as follows.

In this case, the equation is different depending on the relative difference between γ _AS and γ _CS .

(Ⅰ) With,

(Ii) As if

It was divided up.

only, In this case, by satisfying Equation 2 or 3, always form a thin film of a vertical structure.

As can be seen from the above equation, if the B block of the triple block copolymer is selected as a material satisfying Equation 2 or Equation 3, a vertical structure can be obtained regardless of the thickness or other conditions of the thin film.

On the other hand, when preparing a triblock copolymer, the diameter of the cylinder structure can be determined by adjusting the composition or molecular weight from the degree of polymerization.

At this time, the diameter of the cylinder or the distance between the cylinders is proportional to the molecular weight and the proportional index varies from 1/2 to 2/3 (MACROMOLECULES 31: (9) 3136-3138 MAY 5, 1998). The diameter or distance can be adjusted accordingly.

On the other hand, when the ABC triblock copolymer is coated on the substrate, if the B polymer that does not satisfy the above formula is selected, the vertical or horizontal structure can be selectively obtained depending on the thickness of the thin film by adjusting the coating speed or the concentration of the polymer solution. .

Meanwhile, the substrate used may be silicon (Si), silicon oxide (SiO ₂ ), silicon carbide (SiC), or silicon nitride (Si ₃ N ₄ ) substrate, and carbon or other organic materials, such as before thin film coating, may be used. For example, the substrate may be coated with a hexamethyldisilazane (HMDS) to selectively change the surface tension between the substrate and the thin film.

The present invention provides a thin film and a method of manufacturing the thin film in which the cylinder structure of the ABC triple block copolymer is always vertically coated on the substrate, regardless of the thickness of the thin film, the thin film produced by the above method is a semiconductor mask Can be used.

In addition, the method of manufacturing the thin film is capable of adjusting the diameter of the cylinder or the distance between the cylinders, so that a thin film having a vertical cylinder structure having an arbitrary length and diameter can be obtained. It can be said that the application range is wide also as a formation technique and a capacitor for a semiconductor.

Claims (5)

A thin film of the ABC triblock copolymer, characterized in that the cylinder structure is coated perpendicular to the substrate by coating the ABC triblock copolymer comprising a B polymer selected to satisfy the following conditions on the substrate. At this time, the Is the volume fraction of A and B, respectively, remind Is the interfacial tension ([dynes / nm ² ]) between AB and BC blocks, remind Is the surface tension ([dynes / nm ² ]) acting between the A, B, C blocks and the substrate, respectively. A method of manufacturing a thin film of ABC triple block copolymer, characterized in that the cylinder structure is coated vertically with respect to the substrate by coating the ABC triple block copolymer comprising a B polymer selected to satisfy the following conditions. At this time, the Is the volume fraction of A and B, respectively, remind Is the interfacial tension ([dynes / nm ² ]) between AB and BC blocks, remind Is the surface tension ([dynes / nm ² ]) acting between the A, B, C blocks and the substrate, respectively. The method of claim 2, wherein the diameter of the cylinder structure is controlled by adjusting the degree of polymerization of the triple block copolymer. The method of claim 2 or 3, wherein the substrate is a silicon, silicon oxide, silicon carbide, or nitrogenized silicon substrate. The method of claim 4, wherein the substrate is coated with HMDS.