Method for producing polymer film

Abstract

A method for producing a polymer film is disclosed herein. The method is capable of effectively forming a polymer film on a substrate, where the polymer film comprises highly aligned block copolymers without orientation defects, coordination number defects, distance defects, and the like. The method can be applied to production of various patterned substrates.

Claims

1. A method for producing a polymer film, comprising: annealing a polymer film having a block copolymer to form a self-assembled structure of the block copolymer, wherein, during the annealing step, the polymer film is simultaneously maintained at a temperature (T1) on one side of the polymer film and at a temperature (T2) on the opposite side of the polymer film, wherein the block copolymer having a polymer segment A and a polymer segment B that is different from the polymer segment A, and wherein the difference (T1T2) is in a range of 40 C. to 500 C.

2. The method for producing a polymer film according to claim 1, wherein the self-assembled structure is a sphere, cylinder or lamellar structure.

3. The method for producing a polymer film according to claim 1, wherein the self-assembled structure is a vertically oriented structure.

4. The method for producing a polymer film according to claim 1, wherein T1 is maintained in a range of 100 C. to 300 C.

5. The method for producing a polymer film according to claim 1, wherein the polymer segments A and B are each any one segment selected from the group consisting of a polystyrene segment, a poly(alkyl (meth)acrylate) segment, a polyvinylpyrrolidone segment, a polylactic acid segment, a polyvinylpyridine segment, a polyalkylene oxide segment, a polybutadiene segment, a polyisoprene segment and a polyolefin segment.

6. The method for producing a polymer film according to claim 1, wherein the polymer segment A satisfies one or more of Conditions 1 to 3 below: Condition 1: it exhibits a melting transition peak or an isotropic transition peak in a range of 80 to 200 in a DSC analysis: Condition 2: it exhibits an X-ray diffraction (XRD) peak having a half-value width in a range of 0.2 to 0.9 nm.sup.1 within a scattering vector (q) range of 0.5 nm.sup.1 to 10 nm.sup.1: Condition 3: it comprises a side chain, wherein the number (n) of chain-forming atoms in the side chain satisfies Equation 1 below with the scattering vector (q):
3 nm.sup.1 to 5 nm.sup.1=nq/(2)[Equation 1] wherein, n is a number of the chain-forming atoms and q is the smallest scattering vector (q) in which an XRD peak is observed for the block copolymer or the scattering vector (q) in which an XRD peak of the largest peak area is observed.

7. The method for producing a polymer film according to claim 6, wherein the absolute value of the difference in surface energy between the polymer segments A and B is in a range of 2.5 to 7 mN/m.

8. The method for producing a polymer film according to claim 1, wherein the polymer segment A comprises a side chain having 8 or more chain-forming atoms.

9. The method for producing a polymer film according to claim 8, wherein the polymer segment comprises a ring structure and the side chain is substituted on the ring structure.

10. The method for producing a polymer film according to claim 9, wherein no halogen atom is present in the ring structure.

11. The method for producing a polymer film according to claim 8, wherein the polymer segment B comprises 3 or more halogen atoms.

12. The method for producing a polymer film according to claim 11, wherein the polymer segment B comprises a ring structure and the halogen atoms are substituted on the ring structure.

13. A method for producing a patterned substrate, comprising: forming a polymer film on a substrate, wherein the polymer film comprises a block copolymer having a polymer segment A and a polymer segment B different from the segment A; and annealing the polymer film, wherein, during the annealing step, the polymer film is simultaneously maintained at a temperature (T1) on one side of the polymer film and at a temperature (T2) on the opposite side of the polymer film, wherein the difference (T1T2) is in a range of 40 C. to 500 C.

14. The method for producing a patterned substrate according to claim 13, wherein the polymer film is formed in direct contact with the substrate.

15. The method for producing a patterned substrate according to claim 13, further comprising: selectively removing any one polymer segment of the block copolymer forming the self-assembled structure to expose a surface of the substrate, the exposed surface of the substrate underlying the portion of the polymer film that is removed.

16. The method for producing a patterned substrate according to claim 15, further comprising: etching the exposed surface of the substrate using the polymer film as a mask.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a view showing an analysis result of GISAXS for the polymer film of Example 1.

(2) FIGS. 2 and 3 are SEM images of the self-assembled polymer patterns of Examples 1 and 2, respectively.

MODE FOR INVENTION

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

(4) 1. NMR Measurement

(5) NMR analyses were performed at room temperature using an NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. The analytes were diluted in a solvent for NMR measurement (CDCl.sub.3) to a concentration of about 10 mg/ml, and chemical shifts were expressed in ppm.

(6) <Application Abbreviation>

(7) br=broad signal, s=singlet, d=doublet, dd=double doublet, t=triplet, dt=double triplet, q=quartet, p=quintet, m=multiplet.

(8) 2. GPC (Gel Permeation Chromatograph)

(9) The number average molecular weight (Mn) and the molecular weight distribution were measured using GPC (gel permeation chromatography). Into a 5 mL vial, an analyte such as block copolymers of Examples or Comparative Examples or a giant initiator is put and diluted in THF (tetrahydrofuran) to be a concentration of about 1 mg/mL or so. Then, a standard sample for calibration and a sample to be analyzed were filtered through a syringe filter (pore size: 0.45 m) and then measured. As the analytical program, ChemStation from Agilent Technologies was used, and the elution time of the sample was compared with the calibration curve to obtain the weight average molecular weight (Mw) and the number average molecular weight (Mn), respectively, and the molecular weight distribution (PDI) was calculated by the ratio (Mw/Mn) thereof. The measurement conditions of GPC are as follows.

(10) <GPC Measurement Condition>

(11) Instrument: 1200 series from Agilent Technologies

(12) Column: using two PLgel mixed B from Polymer Laboratories

(13) Solvent: THF

(14) Column temperature: 35 C.

(15) Sample concentration: 1 mg/mL, 200 L injection

(16) Standard sample: polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

(17) 3. GISAXS (Grazing Incidence Small Angle X-Ray Scattering)

(18) The grazing incidence small angle X-ray scattering (GISAXS) analysis was performed using a Pohang accelerator 3C beamline. The block copolymer to be analyzed was diluted in fluorobenzene to a solid concentration of about 0.7 weight % to prepare a coating liquid, and the coating liquid was spin-coated on a base material to a thickness of about 5 nm. The coating area was adjusted to 2.25 cm.sup.2 or so (width: 1.5 cm, height: 1.5 cm). The coated polymer film was dried at room temperature for about 1 hour and thermally annealed again at about 160 C. for about 1 hour to induce a phase separation structure. Subsequently, a film, in which the phase separation structure was formed, was formed. After an X-ray was incident on the film at an incident angle in a range of about 0.12 degrees to 0.23 degrees corresponding to the angle between the critical angle of the film and the critical angle of the base material, an X-ray diffraction pattern, which was scattered from the film to a detector (2D marCCD) and exited, was obtained. At this time, the distance from the film to the detector was selected as such a range that the self-assembly pattern formed on the film was well observed within a range of about 2 m to 3 m. As the base material, a base material having a hydrophilic surface (a silicon substrate treated with a piranha solution and having a room temperature wetting angle of about 5 degrees to pure water) or a base material having a hydrophobic surface (a silicon substrate treated with HMDS (hexamethyldisilazane) and having a room temperature wetting angle of about 60 degrees to pure water) was used.

(19) 4. XRD Analysis Method

(20) The XRD analysis was performed by transmitting X rays to a sample at a Pohang accelerator 4C beamline to measure the scattering intensity according to the scattering vector (q). As the sample, a polymer in a powder state dried by purifying a synthesized polymer without special pretreatment and then maintaining it in a vacuum oven for one day or so, was placed in a cell for XRD measurement and used. Upon the XRD pattern analysis, an X-ray with a vertical size of 0.023 mm and a horizontal size of 0.3 mm was used and a 2D marCCD was used as a detector. A 2D diffraction pattern scattered and exited was obtained as an image. The obtained diffraction pattern was analyzed by a numerical analytical method to which a least-square method was applied to obtain information such as a scattering vector and a half-value width. Upon the analysis, an origin program was applied, and the profile of the XRD patterns was subjected to Gaussian fitting in a state where a portion showing the smallest intensity in the XRD diffraction patterns was taken as a baseline and the intensity in the above was set to zero, and then the scattering vector and the half-value width were obtained from the fitted results.

(21) 5. Measurement of Surface Energy

(22) The surface energy was measured using a drop shape analyzer (DSA100 product from KRUSS). A coating liquid was prepared by diluting the substance (polymer), which is measured, in fluorobenzene to a solid concentration of about 2 weight %, and the prepared coating liquid was spin-coated on a silicon wafer to a thickness of about 50 nm and a coating area of 4 cm.sup.2 (width: 2 cm, height: 2 cm). The coating layer was dried at room temperature for about 1 hour and then subjected to thermal annealing at about 160 C. for about 1 hour. The process of dropping the deionized water whose surface tension was known on the film subjected to thermal annealing and obtaining the contact angle thereof was repeated five times to obtain an average value of the obtained five contact angle values. In the same manner, the process of dropping the diiodomethane whose surface tension was known thereon and obtaining the contact angle thereof was repeated five times to obtain an average value of the obtained five contact angle values. The surface energy was obtained by substituting the value (Strom value) regarding the solvent surface tension by the Owens-Wendt-Rabel-Kaelble method using the obtained average values of the contact angles for the deionized water and diiodomethane. The numerical value of the surface energy for each polymer segment of the block copolymer was obtained for a homopolymer made of only the monomer forming the polymer segment by the above-described method.

(23) 6. GIWAXS (Grazing Incidence Wide Angle X-Ray Scattering)

(24) The grazing incidence wide angle X-ray scattering (GIWAXS) analysis was performed using a Pohang accelerator 3C beamline. The homopolymer to be analyzed was diluted in toluene to a solid concentration of about 1 weight % to prepare a coating liquid, and the coating liquid was spin-coated on a base material to a thickness of about 30 nm. The coating area was adjusted to about 2.25 cm.sup.2 (width: 1.5 cm, height: 1.5 cm). The coated polymer film was dried at room temperature for about 1 hour and then subjected to thermal annealing at a temperature of about 160 C. for about 1 hour to form a film. After an X-ray was incident on the film at an incident angle in a range of about 0.12 degrees to 0.23 degrees corresponding to the angle between the critical angle of the film and the critical angle of the base material, an X-ray diffraction pattern, which was scattered from the film to a detector (2D marCCD) and exited, was obtained. At this time, the distance from the film to the detector was selected as such a range that the crystal or liquid crystal structure formed on the film was well observed within a range of about 0.1 m to 0.5 m. As the base material, a silicon substrate treated with a piranha solution and having a room temperature wetting angle of about 5 degrees to pure water was used. In the GIWAXS spectrum, the scattering intensity in the azimuthal angle range of 90 degrees to 90 degrees of the diffraction pattern in the range of 12 nm.sup.1 to 16 nm.sup.1 (azimuthal angle when the upward direction of the diffraction pattern (out-of-plane diffraction pattern) is set as 0 degrees) was plotted, and the half-value width was obtained from the graph through Gauss fitting. Furthermore, when half of the peak was observed upon Gauss fitting, twice the value of the obtained half-value width (FWHM) was defined as the half-value width of the peak.

(25) 7. DSC Analysis

(26) The DSC analysis was performed using PerkinElmer DSC800 equipment. Using the equipment, it was performed by a method in which the sample to be analyzed was heated at a speed of 10 C. per minute from 25 C. to 200 C., cooled again at a speed of 10 C. per minute from 200 C. to 80 C., and raised at a speed of 10 C. per minute from 80 C. to 200 C. under a nitrogen atmosphere to obtain an endothermic curve. The obtained endothermic curve was analyzed to obtain a temperature (melting transition temperature, Tm) indicating a melting transition peak or a temperature (isotropic transition temperature, Ti) indicating an isotropic transition peak, and the area of the peak was obtained. Here, the temperature was defined as the temperature corresponding to the apex of each peak. The area per unit mass of each peak is defined as the value obtained by dividing the area of each peak by the mass of the sample, and this calculation can be calculated using the program provided by the DSC equipment.

Preparation Example 1. Synthesis of Monomer (A)

(27) A monomer (DPM-C12) of Formula A below was synthesized in the following manner. Hydroquinone (10.0 g, 94.2 mmol) and 1-bromododecane (23.5 g, 94.2 mmol) were placed in a 250 mL flask, dissolved in 100 mL of acetonitrile, and then an excess amount of potassium carbonate was added thereto and reacted at 75 C. for about 48 hours under a nitrogen condition. After the reaction, the remaining potassium carbonate was filtered off and the acetonitrile used in the reaction was also removed. A mixed solvent of DCM (dichloromethane) and water was added thereto to work up the mixture, and the separated organic layers were collected and passed through MgSO.sub.4 to be dehydrated. Subsequently, the target product (4-dodecyloxyphenol) (9.8 g, 35.2 mmol) in a white solid phase was obtained in a yield of about 37% using dichloromethane in column chromatography.

(28) <NMR Analysis Result>

(29) .sup.1H-NMR (CDCl.sub.3): d6.77 (dd, 4H); d4.45 (s, 1H); d3.89 (t, 2H); d1.75 (p, 2H); d1.43 (p, 2H); d1.33-1.26 (m, 16H); d0.88 (t, 3H).

(30) The synthesized 4-docecyloxyphenol (9.8 g, 35.2 mmol), methacrylic acid (6.0 g, 69.7 mmol), DCC (dicyclohexylcarbodiimide) (10.8 g, 52.3 mmol) and DMAP (p-dimethylaminopyridine) (1.7 g, 13.9 mmol) were placed in the flask and 120 mL of methylene chloride was added thereto, and then reacted at room temperature for 24 hours under nitrogen. After completion of the reaction, the salt (urea salt) generated during the reaction was filtered off and the remaining methylene chloride was also removed. Impurities were removed using hexane and DCM (dichloromethane) as the mobile phase in column chromatography and the product obtained again was recrystallized in a mixed solvent of methanol and water (1:1 mix) to obtain the target product (7.7 g, 22.2 mmol) in a white solid phase in a yield of 63%.

(31) <NMR Analysis Result>

(32) .sup.1H-NMR (CDCl.sub.3): d7.02 (dd, 2H); d6.89 (dd, 2H); d6.32 (dt, 1H); d5.73 (dt, 1H); d3.94 (t, 2H); d 2.05 (dd, 3H); d1.76 (p, 2H); d1.43 (p, 2H); 1.34-1.27 (m, 16H); d0.88 (t, 3H).

(33) ##STR00005##

(34) In Formula A, R is a linear alkyl group having 12 carbon atoms.

(35) XRD and DSC Analyses

(36) A homopolymer was prepared using the monomer (A) of Preparation Example 1, and GIWAXS and DSC were analyzed for the prepared homopolymer. Here, the homopolymer was prepared by a method of synthesizing a macromonomer using the monomer (A) in the following examples. As a result of the DSC analysis for the homopolymer, the corresponding polymer showed a melting transition temperature of about 3 C. and an isotropic transition temperature of about 15 C. Also, the ratio (M/I) of the area (M) of the melting transition peak to the area (I) of the isotropic transition peak in the DSC analysis of the homopolymer was about 3.67, the half-value width of the peak in an azimuthal angle of 90 degrees to 70 degrees of the diffraction pattern of the scattering vector in a range of 12 nm.sup.1 to 16 nm.sup.1 in GIWAXS was about 48 degrees, and the half-value width of the peak in an azimuthal angle of 70 degrees to 90 degrees of the diffraction pattern of the scattering vector in a range of 12 nm.sup.1 to 16 nm.sup.1 in GIWAXS was about 58 degrees. Furthermore, in the X-ray diffraction analysis (XRD), a peak having a half-value width of about 0.57 nm.sup.1 or so was observed at a scattering vector value of 1.96 nm.sup.1.

Preparation Example 2. Synthesis of Block Copolymer (A)

(37) 2.0 g of the monomer (A) of Preparation Example 1, 64 mg of cyanoisoproyl dithiobenzoate as an RAFT (reversible addition-fragmentation chain transfer) reagent, 23 mg of AIBN (azobisisobutyronitrile) as a radical initiator and 5.34 mL of benzene were placed in a 10 mL Schlenk flask and stirred at room temperature for 30 minutes under a nitrogen atmosphere, and then an RAFT (reversible addition-fragmentation chain transfer) polymerization reaction was performed at 70 C. for 4 hours. After the polymerization, the reaction solution was precipitated in 250 mL of methanol as an extraction solvent, and then filtered under reduced pressure and dried to prepare a pink macro initiator. 0.3 g of the macro initiator, 2.7174 g of a pentafluorostyrene monomer and 1.306 mL of benzene were placed in a 10 mL Schlenk flask and stirred at room temperature for 30 minutes under a nitrogen atmosphere, and then an RAFT (reversible addition-fragmentation chain transfer) polymerization reaction was performed at 115 C. for 4 hours. After the polymerization, the reaction solution was precipitated in 250 mL of methanol as an extraction solvent, and then filtered under reduced pressure and dried to prepare a pale pink polymer segment copolymer. The yield of the block copolymer was about 18 weight %, and the number average molecular weight (Mn) and the molecular weight distribution (Mw/Mn) were 39,400 and 1.18, respectively. The block copolymer comprises a polymer segment A, which is derived from the monomer (A) of Preparation Example 1 and has 12 chain-forming atoms (the number of carbon atoms of R in Formula A), and a polymer segment B derived from the pentafluorostyrene monomer. Here, the volume fraction of the polymer segment A was about 0.47, and the volume fraction of the polymer segment B was about 0.53. The surface energy and density of the polymer segment A of the block copolymer were 30.83 mN/m and 1 g/cm.sup.3, respectively, and the surface energy and density of the polymer segment B were 24.4 mN/m and 1.57 g/cm.sup.3, respectively. Also, the result obtained by substituting the number of chain-forming atoms (12) in the polymer segment A of the block copolymer and the scattering vector value (q) in which the peak having the largest peak area was identified in the scattering vector range of 0.5 nm.sup.1 to 10 nm.sup.1 upon the X-ray diffraction analysis into the equation nq/(2), respectively, was about 3.75.

Preparation Example 3. Synthesis of Block Copolymer (B)

(38) A block copolymer, in which a number average molecular weight (Mn) and a molecular weight distribution (Mw/Mn) were 17,800 and 1.14, respectively, was prepared by synthesizing it in the same manner as in Preparation Example 2 but controlling the ratio of the monomers and the polymerization conditions, and the like. The block copolymer comprises a polymer segment A, which is derived from the monomer (A) of Preparation Example 1 and has 12 chain-forming atoms (the number of carbon atoms of R in Formula A), and a polymer segment B derived from the pentafluorostyrene monomer. Here, the volume fraction of the polymer segment A was about 0.69, and the volume fraction of the polymer segment B was about 0.31. The surface energy and density of the polymer segment A of the block copolymer were 30.83 mN/m and 1 g/cm.sup.3, respectively, and the surface energy and density of the polymer segment B were 24.4 mN/m and 1.57 g/cm.sup.3, respectively. Also, the result obtained by substituting the number of chain-forming atoms (12) in the polymer segment A of the block copolymer and the scattering vector value (q) in which the peak having the largest peak area was identified in the scattering vector range of 0.5 nm.sup.1 to 10 nm.sup.1 upon the X-ray diffraction analysis into the equation nq/(2), respectively, was about 3.75.

Example 1

(39) A polymer film was formed on a silicon wafer substrate using the block copolymer (A) of Preparation Example 2. Specifically, a coating liquid prepared by diluting the block copolymer in fluorobenzene to a solid concentration of about 1.2 weight % was spin-coated on the substrate to a thickness of about 50 nm and dried at room temperature for about 1 hour. Subsequently, the temperature of the upper side of the polymer film was set at a temperature of about 180 C., the temperature of the lower side was maintained at about 195 C., and the film was annealed for about 180 seconds to form a self-assembled film. For the formed film, GISAXS analysis and SEM (scanning electron microscope) image capture were performed. FIG. 1 is a GISAXS analysis result for the polymer film, and FIG. 2 is an SEM image of the self-assembled film. It can be confirmed that the self-assembled film has formed a vertically oriented lamellar phase.

Example 2

(40) A polymer film was formed on a silicon wafer substrate using the block copolymer (B) of Preparation Example 3. Specifically, a coating liquid prepared by diluting the block copolymer in fluorobenzene to a solid concentration of about 0.7 weight % was spin-coated on the substrate to a thickness of about 35 nm and dried at room temperature for about 1 hour. Subsequently, the temperature of the upper side of the polymer film was set at a temperature of about 240 C., the temperature of the lower side was maintained at about 80 C., and the film was annealed for about 1 hour to form a self-assembled film. For the formed film, SEM (scanning electron microscope) image capture was performed. FIG. 3 is an SEM image of the self-assembled film. It can be confirmed that the self-assembled film has formed a vertically oriented cylinder pattern.