JP2012224485A - Method for transferring transparent conductive carbon film - Google Patents

Abstract

Provided is a method for reproducibly peeling a carbon film from a transfer substrate without reusing the growth substrate in order to reuse the growth substrate, and a continuous film forming method can be applied. Provided is a carbon film peeling method.
The transparent conductive carbon film formed is controlled by controlling the peel strength (F) between the transparent conductive carbon film formed by the CVD method and the growth substrate to 1 N / cm or less. It can be easily peeled off from the substrate and can be easily transferred to a transfer substrate. As a result, the growth substrate can be peeled off without causing any damage and the formed transparent conductive carbon film can be continuously transferred and processed from the growth substrate to the transfer substrate. It becomes possible.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a transparent conductive carbon film for use in a transparent conductive film, a transparent electrode, and the like. In particular, the transparent conductive carbon film is peeled from a growth substrate and transferred to a transfer substrate. It relates to a method of manufacturing.

  The transparent conductive carbon film is called one or more planar crystal SP2-bonded carbon atoms. The transparent conductive carbon film is described in detail in Non-Patent Documents 1 and 2. The transparent conductive carbon film is expected to be used as a transparent conductive film or a transparent electrode because of its high light transmittance and electrical conductivity.

In recent years, a method for forming a transparent conductive carbon film on the surface of a copper foil by chemical vapor deposition (CVD) has been developed (Non-Patent Documents 3 and 4). The transparent conductive carbon film forming method based on this copper foil is based on a thermal CVD method, and methane gas, which is a raw material gas, is thermally decomposed at about 1000 ° C. A transparent conductive carbon film of several layers is formed from the layers.
Further, recently, the base material temperature is set to 500 ° C. or lower, the pressure is set to 50 Pa or lower, and the oxidation for suppressing the oxidation of the base material surface to a carbon-containing gas or a mixed gas composed of a carbon-containing gas and an inert gas. There has also been proposed a method of depositing a transparent conductive carbon film on the substrate surface by a microwave surface wave plasma method in a gas atmosphere in which an inhibitor is added as an additive gas (Non-Patent Document 5).

In addition, when the transparent conductive carbon film formed on the growth substrate is used as a transparent electrode, the transparent conductive carbon film formed on the growth substrate is peeled off or transferred from the growth substrate. It is necessary to transfer to a substrate for use.
However, the transparent conductive carbon film formed on the growth base material by the thermal CVD (about 1000 ° C.) method described in the above-mentioned Patent Documents 3 and 4 is the same as the growth base material and the transparent conductive carbon film. Since the peel strength or interaction between the films is strong, the formed transparent conductive carbon film is difficult to peel off from the growth substrate or to be transferred to the transfer substrate. Therefore, generally, when the transparent conductive carbon film is transferred to the transfer substrate, the growth substrate is melted and peeled off using an etching solution (Non-patent Document 6, Patent Document 1). . In addition, a method of peeling the transparent conductive carbon film from the growth substrate using an adhesive material between the formed transparent conductive carbon film and the transfer substrate has been developed (Patent Document 2).

Kumi Yamada, Chemistry and Industry, Vol. 61 (2008) pp.1123-1127 Y. Wu, P. Qiao, T. Chong, Z. Shen, Adv. Mater. 14 (2002) pp. 64-67 X. Li, W. Cai, J. An, S. Kim, J. Nah, D. Yang, R. Piner, A. Velamakanni, I. Jung, E. Tutuc, SK Banerjee, L. Colombo, RS Ruoff, Science, Vol.324 (2009) pp.1312-1314. X. Li, Y. Zhu, W. Cai, M. Borysiak, B. Han, D. Chen, R. D. Piner, L. Colombo, R. S. Ruoff, Nano Letters, Vol. 9 (2009) pp.4359-4363. Autumn 2010 (71th) JSAP Academic Lecture Proceedings 16a-ZF-2 S. Bae et al. Nature Nanotechnology Vol. 5, pp.574-578 (2010).

JP 2009-298683 A JP 2011-6265 A

  As described above, the transparent conductive carbon film is expected to be used as a transparent conductive film and a transparent electrode because of its high light transmittance and electrical conductivity. When the transparent conductive carbon film is used for a transparent conductive film or a transparent electrode, it is necessary to transfer the transparent conductive carbon film from a growth base material to a transfer base material.

However, in the method described in Non-Patent Document 6 and Patent Document 1, that is, a method of peeling a transparent conductive carbon film by dissolving a metal substrate such as Cu or Ni using an etching solution, Cu The base material melts and cannot be reused. Furthermore, since impurities such as FeCl ₃ , Cu, a mixture, and a liquid are generated from the etching process, there is a problem that the purity of the transferred transparent conductive carbon film is deteriorated and the characteristics of the transparent conductive carbon film are also deteriorated. There was found.

  In addition, in the method described in Patent Document 2, that is, a method in which the transparent conductive carbon film is peeled off from the growth substrate using an adhesive material or the like between the formed transparent conductive carbon film and the transfer substrate, Since the transparent conductive carbon film can be peeled only partially from the growth substrate, it has been found that precise control of the thickness, electric resistance (sheet resistance), and transmittance of the transparent conductive carbon film is problematic.

  In addition, a so-called continuous film forming method is applied in which a transparent conductive carbon film is formed while a roll-shaped growth substrate is continuously fed to a film forming apparatus, and then continuously wound with a transfer roll. If it is possible, the production efficiency is improved and the production at an industrially low cost is possible, but the Cu base material is etched or a part of the transparent conductive carbon film remains on the Cu base material. However, it is difficult to apply such a continuous film forming method with a conventional method.

As described above, since the transparent conductive carbon film has a strong interaction between the growth base materials, it has been found that it is difficult to transfer the transparent conductive carbon film by the conventional method.
The present invention has been made in view of such problems in the prior art, and a carbon film produced by a CVD method without dissolving a growth substrate in order to reuse the growth substrate is used as a growth substrate. An object of the present invention is to provide a method for producing a carbon film that peels and transfers from a material to a transfer substrate with good reproducibility.

  As a result of intensive studies to solve the above problems by the present inventors, a step of weakening the peel strength (F) between the transparent conductive carbon film formed by the plasma CVD method and the growth substrate is provided, By controlling the peel strength to 1 N / cm or less, the formed transparent conductive carbon film is easily peeled off from the growth base material, so that it can be easily transferred to the transfer base material and the above-mentioned object can be achieved. It was.

The present invention has been completed based on this finding. According to the present invention, the following inventions are provided.
[1] In a method for producing a transparent conductive carbon film by peeling a transparent conductive carbon film formed on a growth base material by a CVD method from the growth base material and transferring it to a transfer base material. A method for producing a transparent conductive carbon film, comprising a step of weakening the peeling strength between the growth base material and the carbon film before peeling.
[2] The method for producing a transparent conductive carbon film according to [1], wherein the step of weakening the peel strength sets the peel strength to 1 N / cm or less.
[3] The step of weakening the peel strength is a step of giving a temperature difference of 200 ° C. or more for a predetermined time at a temperature of 300 ° C. or lower and from a low temperature to a high temperature or from a high temperature to a low temperature [1] or [ 2] The manufacturing method of the transparent conductive carbon film as described in 2].
[4] The method for producing a transparent conductive carbon film according to [3], wherein the step of weakening the peel strength is a step of immersing in a liquid nitrogen solution.
[5] The method for producing a transparent conductive carbon film according to any one of [1] to [3], wherein the peeling step is a step of immersing in an acid or salt solution.
[6] The method for producing a transparent conductive carbon film according to [5], wherein the acid aqueous solution is a 0.01 M or less sulfuric acid aqueous solution.
[7] The method for producing a transparent conductive carbon film according to any one of [1] to [6], wherein the transparent conductive carbon film is graphene.
[8] The method for producing a transparent conductive carbon film according to any one of [1] to [7], wherein the CVD method is performed by a plasma CVD method at 500 ° C. or lower.
[9] The method for producing a transparent conductive carbon film according to any one of [1] to [8], wherein the growth base material is a copper base material.
[10] Using a roll growth substrate, forming a transparent conductive carbon film on the growth substrate by a CVD method, peeling the transparent conductive carbon film from the roll growth substrate, and transferring the film The method for producing a transparent conductive carbon film according to any one of [1] to [9], wherein the transfer substrate is continuously wound on a roll after being transferred to the substrate for transfer. .
[11] A carbon film laminate obtained by the method according to any one of [1] to [10], comprising three layers of a transfer substrate / transparent conductive carbon film / growth substrate, A carbon film laminate, wherein a peel strength between the growth substrate and the transparent conductive carbon film is 1 N / cm or less.
[12] A carbon film laminate obtained by the method according to any one of [1] to [10], having a transparent conductive carbon film peel-transferred onto a transfer substrate.

  According to the present invention, (1) the transparent conductive carbon film can be peeled off from the growth base material without damage or dissolution of the growth base material. (2) The transparent conductive carbon film can be peeled off without being left on the growth substrate and without being damaged. (3) Impurities due to the etching process are not mixed into the formed transparent conductive carbon film. (4) Since the growth base material can be reused, it can be applied to a continuous film forming method. (5) The effect that the transparent conductive carbon film can be peeled industrially at low cost is obtained.

The figure which shows typically the process of manufacturing a transparent conductive carbon film continuously using the method of this invention. The figure which shows typically the microwave surface wave plasma CVD apparatus used for this invention It is a photograph showing the transfer result of the transparent conductive carbon film, (A) is before transfer, (B) is untreated, (C) is subjected to the chemical treatment of Example 2, (D) shows what performed the physical process of Example 1, respectively. Optical micrograph of the surface of a transparent conductive carbon film formed on a copper foil growth substrate Raman spectra of transparent conductive carbon films formed on copper foil growth substrates Optical micrograph of the surface of a transparent conductive carbon film transferred onto a PET transfer substrate Raman spectrum of transparent conductive carbon film transferred onto PET transfer substrate Optical micrograph of the surface of the copper foil growth substrate after transfer Raman spectra of substrate for copper foil growth after transfer

An embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic view showing steps of continuously producing a carbon film using the method according to the present invention.
As shown in FIG. 1, the method for producing a carbon film of the present invention includes a step of preparing a first roll (1) around which a growth base material (3) is wound, and pulling out the growth base material into a plasma CVD apparatus. A film forming step (4) for introducing and forming a transparent conductive carbon film (5) on the growth substrate by plasma CVD, a step (6) for reducing the peel strength between the carbon film and the growth substrate, (7) A step (13) of peeling and transferring the carbon film from the growth base material to the transfer base material, and a step of winding the transfer base material provided with the transferred carbon film with the roll 10.
In the present invention, the growth substrate is a metal substrate such as copper (Cu), iron (Fe), nickel (Ni), aluminum (Al), or the like.

In the present invention, the CVD method used is not particularly limited, but preferably, the microwave surface wave plasma CVD method described in Non-Patent Document 5 or the like can be used at a low temperature. The microwave surface wave plasma is described in detail, for example, in the document “Hideo Sakurai, Plasma Electronics, Ohmsha 2000, p.124-125”. Accordingly, the temperature can be sufficiently lower than the melting point of the film formation substrate, and uniform plasma can be generated over a large area.
In the examples described later, the plasma was diagnosed by the Langmuir probe method (single probe method), and as a result, the electron density was 10 ¹¹ to 10 ¹² / cm ³ , and the cut-off electron density for microwaves with a frequency of 2.45 GHz. 4 × 10 ¹⁰ / cm ³ was exceeded, and it was confirmed that the surface wave plasma was generated and maintained by surface waves. The Langmuir probe method is described in detail, for example, in the document “Hideo Sakurai, Plasma Electronics, Ohmsha 2000, p.58”.

Next, as shown in FIG. 1, the transparent conductive carbon film (5) formed on the growth substrate is introduced into at least one of the steps (6) and (7) for decreasing the peel strength.
In the step (6), as one method, physical strength is used to achieve a peel strength (F) between the transparent conductive carbon film and the growth substrate of 1 N / cm or less.
Here, “physical treatment” means that a temperature difference of 200 ° C. or more is predetermined on a growth base material on which a transparent conductive carbon film is formed at 300 ° C. or less, from low temperature to high temperature, or from high temperature to low temperature. This is a process of giving time, and may be performed once or may be divided into a plurality of times.
This treatment is based on the knowledge that the coefficient of thermal expansion of the transparent conductive carbon film formed on the metal substrate is very small compared to the coefficient of thermal expansion of the metal that is the growth substrate. When the laminated body in which is laminated is heated or cooled, the peel strength between the growth substrate and the transparent conductive carbon film can be weakened by the difference in the coefficient of thermal expansion.
In order to set the peel strength (F) between the transparent conductive carbon film and the growth substrate to 1 N / cm or less, it is necessary to give a temperature difference of 200 ° C. or more. Moreover, the temperature difference to be applied is not limited as long as the growth substrate and the transparent conductive carbon film can be peeled off, and the temperature on the high temperature side is 300 ° C. or less in consideration of the influence on both.
Moreover, as a means for giving a temperature difference of 200 ° C. or higher from low temperature to high temperature or from high temperature to low temperature, any method of heating or cooling may be used, but from the viewpoint of simplicity, a method using liquid nitrogen is preferable.
The treatment time is appropriately determined depending on the size of the growth substrate used, the heat capacity of the heating means or the cooling means, etc. For example, when liquid nitrogen at about -196 ° C. is used, it may be immersed for about 5 seconds.

In the step (7), as another method, the peel strength (F) between the transparent conductive carbon film and the growth substrate is realized to 1 N / cm or less by using chemical treatment.
Here, “chemical treatment” is a step of treatment with an aqueous solution of an acid or salt, and after the treatment, a step of washing with pure water and a step of drying are provided.
As the acid, a strong acid such as sulfuric acid or HCl, and a weak acid such as phosphoric acid or acetic acid can be used. As the salt, KCl, NaCl or the like can be used.
The concentration of the aqueous solution of these acids or salts is determined on the condition that the transparent conductive carbon film can be easily peeled without damaging the metal substrate, the type of metal used for the substrate, the treatment time, and the aqueous solution temperature ( For example, when using a copper base material, it is as follows at room temperature to 50 ° C. or lower: In the case of H ₂ SO 4: 0.01 M, 12 seconds or shorter 10 minutes or less at 0.0001M, HCl: 10 minutes or less at 0.05M, 120 minutes or less at 0.0001M KCl: 60 minutes at 0.05M,
In the case of NaCl;

  The present invention is characterized by having at least one of the steps (6) and (7) for weakening the peel strength, whereby the peel strength between the growth substrate and the carbon film is 1 N / A carbon film laminate having a size of cm or less is obtained.

Next, the carbon film laminate in which the peeling strength between the growth substrate and the carbon film is weakened is introduced into the peeling / transferring step.
As shown in FIG. 1, the peeling / transfer process is performed by applying pressure or pressure and heat by a roll press, so that three or more layers of the transfer substrate / transparent conductive carbon film / growth substrate are stacked. And a step (13) of peeling and transferring the transparent conductive film from the growth base material to the transfer base material through a step (pressure / heat application step) (11) for producing a film laminate.

  In the pressure / heat application step (11), by applying pressure or pressure and heat, a carbon film laminate (12) in which three layers of transfer substrate / transparent conductive carbon film / growth substrate are stacked is produced. Is done. As the pressure / heat application means in the step (11), there are a roll press, a pressure press (unidirectional press), nanoimprint, etc., pressure (low / medium, 5 MPa or less), or pressure and heating (from room temperature to 100 ° C. or lower).

  In the present invention, the transfer substrate (8) is preferably a plastic material such as polyethylene terephthalate (PET), polycarbonate (PC), polyester film (for example, DIAFOIL Mitsubishi products), a composite material with paper, a glass substrate, or the like. . In particular, in the present invention, since the surface treatment of the transfer substrate is not necessary, it is possible to use an organic solar cell thin film or an organic EL thin film formed on a plastic or glass substrate.

  The transfer substrate (8) wound around the third roll (9) is wound around the fourth roll (10) after the transparent conductive carbon film is transferred in the step (13). On the other hand, the peeled growth base material (3) is wound around the second roll (2), and the carbon film laminate in which the transparent conductive carbon film (14) is formed on the transfer base material (8). Is obtained.

  In the present invention, a pattern can be formed on the surface of the transparent conductive carbon film by applying a pattern to the surface of the transfer substrate (8) or the surface of the roll press.

In the present invention, since the growth substrate is not damaged or melted, it can be reused. Therefore, the growth substrate circulates between the first roll (1) and the second roll (2). It becomes possible. Therefore, as shown in FIG. 1, it is possible to provide a manufacturing method for continuously forming and processing a transparent conductive carbon film by a roll-to-roll method at an industrial high throughput.
In addition, in FIG. 1, although the process of manufacturing a transparent conductive carbon film continuously using the method of this invention was shown, the method of this invention is not restricted to this, For example, each process is discontinuous. Needless to say, the present invention can be applied to other transparent conductive carbon film production methods such as the method of carrying out the method, and the method of performing a part of the method in a discontinuous manner.

Specifically, the present invention will be described based on examples, but the present invention is not limited to these examples.
(Deposition of transparent conductive carbon film)
In this example, a copper foil having a thickness of 33 μm was used as a base material, and a plasma CVD process was performed using a microwave surface wave plasma CVD apparatus. FIG. 2 is a diagram schematically showing the microwave surface wave plasma CVD apparatus used in this example.
The microwave surface wave plasma CVD apparatus shown in FIG. 2 is attached to a metal reaction vessel (110) having an open upper end and an upper end portion of the reaction vessel (110) in an airtight manner via a metal support member (104). It is composed of a quartz window (103) for introducing the generated microwave and a rectangular microwave waveguide (102) with a slot attached to the top thereof.
In the present embodiment, a copper foil base material is placed inside the reaction vessel (110), and a CVD process is performed. The processing procedure is as follows.

The said copper foil base material (105) was installed in the sample stand (106) provided in the plasma generation chamber (101) in a microwave surface wave plasma CVD reaction container (110). Next, the reaction chamber was evacuated to 1 × 10 ⁻³ Pa or less through the exhaust pipe (108). A cooling water pipe (111) is wound around the reaction chamber, and cooling water is supplied thereto to cool the reaction chamber. The sample stage was made of copper, and the cooling water was supplied through the cooling water supply / drain pipe (107) to cool the sample.

The height of the sample stage was adjusted so that the distance between the quartz window (103) and the copper foil base material was 130 mm.
Next, a CVD processing gas was introduced into the reaction chamber through a CVD processing gas introduction pipe (109). The CVD processing gas was methane gas 5 SCCM and argon gas 95 SCCM. The pressure in the reaction chamber was maintained at 2 Pa using a pressure adjusting valve connected to the exhaust pipe (108).
Plasma was generated at a microwave power of 10.5 kW, and a plasma CVD treatment of the copper foil base material (105) was performed. The temperature of the substrate during the plasma treatment was measured by bringing an alumel-chromel thermocouple into contact with the substrate surface. The temperature of the copper foil base material was 500 ° C. or lower throughout the plasma CVD process.
As a result of the above plasma CVD treatment, a sample was obtained in which a transparent conductive carbon film thin film was laminated on a copper foil substrate, and a laminate of the copper foil and the transparent conductive carbon film thin film was formed. The plasma CVD processing time is 6 minutes.
In this example, in order to make it easy to observe the state of subsequent peeling and transfer, a film having a thickness greater than that of the normally used transparent conductive carbon film was used.

Table 1 shows the measurement results of the peel strength (F) between the copper foil growth base and the transparent conductive carbon film.
In the example, it was found that the peel strength between the transparent conductive carbon film and the growth substrate was 1.33 N / cm.

In the present invention, the peel strength (F) is an index of strength between the transparent conductive carbon film and the growth substrate, and the measurement method is as follows.
1) A sample having a three-layer structure of adhesive tape / transparent conductive carbon film / growth substrate is prepared.
2) Fix the sample on the test bench and apply a tensile force (or load) to the tip of the adhesive tape using a tensile testing device (Shimadzu AGS-X).
3) Measure the average load with a tensile tester (reference method ASTM D-903 etc., conditions are constant angle (90 °), constant speed (100 mm / min), per unit width adhering to adhesive tape (2 cm )).
This time, the selected adhesive tape (Scotch 3M, mending tape) has strong adhesive strength with the transparent conductive carbon film, so that the adhesive tape and the transparent conductive carbon film can be peeled from the growth substrate at the same time. Since this method measures the peel strength between the transparent conductive carbon film and the growth substrate, the peel strength (F) (N / cm) = average load (N) / tape width (cm). Become.

FIG. 3 is a photograph showing the result of transferring the formed transparent conductive carbon film from the copper foil growth base material to the PET transfer base material.
FIGS. 3A1 and 3A2 are a prepared transparent conductive carbon film formed on a copper foil growth base material and a PET transfer base material, respectively.
3 (B1) and 3 (B2) are each transferred without performing a process for reducing the peel strength, and the transparent conductive carbon film formed on the copper foil growth base material after the transfer remains. (FIG. 3 (B1)), it was found that the transparent conductive carbon film was not deposited on the transfer substrate (FIG. 3 (B2)).
The transparent conductive carbon film formed from the experimental results cannot be transferred from the growth base material to the PET film. To solve this problem, the transparent conductive carbon film formed on the growth base material is used. It was found that membrane processing was necessary.

(Example 1: Stripping transfer of transparent conductive carbon film 1)
The above-mentioned transparent conductive carbon film formed on a copper foil growth substrate using a microwave surface wave plasma CVD apparatus is placed in a container containing liquid nitrogen (-196 ° C.) for about 5 seconds, After heating at 30 ° C. for about 5 seconds, a laminate in which three layers of transfer substrate / transparent conductive carbon film / growth substrate were superposed was prepared. Finally, the growth base material of the laminate was removed, and the transparent conductive carbon film was transferred to the transfer base material.

  FIGS. 3D3 and 3D4 show that the formed transparent conductive carbon film can be transferred from the copper foil growth base material to the PET transfer base material after the liquid nitrogen treatment. From this result, it was found that the transparent conductive carbon film was transferred to the PET film (FIG. 3 (D4)), and no transparent conductive carbon film remained on the growth substrate (FIG. 3 (D3)). ).

Evaluation was performed with an optical microscope or a Raman spectrophotometer. While observing the surface of the transparent conductive carbon film or the surface of the growth substrate (70 × 60 micrometers, objective lens 100 times) with an optical microscope using a Raman microscope (Horiba XploRA), a Raman spectrum (excitation wavelength: 638 nm, Range 250-3500 cm ⁻¹ , objective lens 100 times).
Bands important for evaluation of the transparent conductive carbon film by Raman scattering spectroscopy are 2D band (2652 cm ⁻¹ ), G band (1592 cm ⁻¹ ), D band (1322 cm ⁻¹ ), and D ′ band (1617 cm ⁻¹ ). It is. The G band is due to the normal six-membered ring, and the 2D band is due to the overtone of the D band. The D band is a peak due to a defect in a normal six-membered ring. The D ′ band is also a peak induced by defects, and is considered to be caused by the end portion of the laminate of transparent conductive carbon films of several to several tens of layers. Then, from the intensity ratio of the 2D band and the G band peak of the Raman scattering spectrum, it is determined whether or not the laminated transparent conductive carbon film is graphene.

FIG. 4 (A) and FIG. 4 (B) show the surface and Raman spectrum of the transparent conductive carbon film formed on the copper foil growth base before transfer, respectively.
The surface and Raman spectrum of the transparent conductive carbon film transferred onto the PET transfer substrate after the transfer are shown in FIG. 4 (C) and FIG. 4 (D), respectively.
In FIGS. 4B and 4D, peaks of both the G band and the 2D band are observed, and it is clear that this is due to the transparent conductive carbon film. Then, the intensity ratio of the 2D band to the G band peak of the Raman spectrum shown in FIGS. 4B and 4D and the D ′ band are observed, so that the formed transparent conductive carbon film is formed. Has a structure in which a stack of graphene films of several to several tens of layers is mixed. Further, as a result of comparing FIG. 4B and FIG. 4D, it was confirmed that the characteristics of the Raman spectrum of the transparent conductive carbon film did not change before and after the transfer.

Moreover, the surface and Raman spectrum of the copper foil growth base material after transfer are shown in FIG. 4 (E) and FIG. 4 (F).
As is clear from FIGS. 4E and 4F, after the transfer, the transparent conductive carbon film does not remain on the surface of the growth substrate, and no scattered Raman is detected. (Background level).

From the above results, it was confirmed that the transparent conductive carbon film was transferred to the PET film, and it was also confirmed that the transparent conductive carbon film did not remain on the growth substrate.
Further, Table 1 shows the measurement results of peel strength. From the results in Table 1, it was found that the peel strength (F) decreased from 1.33 N / cm to 0.7 N / cm. As a difference in the coefficient of thermal expansion between the transparent conductive carbon film and the growth substrate, it is considered that the interaction between the transparent conductive carbon film and the growth substrate is weakened. The carbon film can be transferred to a PET film. It was found that the copper foil growth base material can be reused without being damaged.

(Example 2: Release transfer of transparent conductive carbon film 2)
The above-mentioned transparent conductive carbon film formed on the copper foil growth base material using the microwave surface wave plasma CVD method is about 12 seconds in an aqueous solution of sulfuric acid (H ₂ SO ₄ , 0.01M, room temperature). After the treatment, it was washed with pure water (room temperature) and dried at 30 ° C. Next, a laminate in which three layers of transfer substrate / transparent conductive carbon film / growth substrate were superposed was prepared. Finally, the growth base material of the laminate was removed, and the transparent conductive carbon film was transferred to the transfer base material.

  The transferred transparent conductive carbon film was evaluated by the optical microscope or the Raman spectrophotometer method in the same manner as in Example 1. As a result, it was confirmed that the Raman characteristics of the transparent conductive carbon film did not change before and after the transfer. It was confirmed that the transparent conductive carbon film was transferred to the PET film, and it was also confirmed that the transparent conductive carbon film did not remain on the growth substrate after the transfer.

Further, Table 1 shows the measurement results of peel strength.
As shown in Table 1, when a plurality of phenomena (liquid diffusion, reaction, gas generation, etc.) occur between the transparent conductive carbon film and the growth substrate, the transparent conductive carbon film And the growth substrate weakened, and the peel strength (F) was reduced from 1.33 N / cm to 0.50 N / cm (Table 1). As a result, it was found that the transparent conductive carbon film was transferred from the copper foil growth base material to the transfer base material (PET) by the roll press method.

(Measurement of resistivity and transmittance of the transferred transparent conductive carbon film)
In order to measure the resistivity and transmittance of the transferred transparent conductive carbon film, the conditions of the above-mentioned CVD process are as follows: CVD process gas: methane gas 29.9 SCCM, argon gas 20 SCCM, hydrogen gas 10 SCCM, pressure in the reaction chamber : 3 Pa, microwave power: 13.5 kW / 3 units, processing time: 3 minutes, a film having a thickness smaller than the above-mentioned transparent conductive carbon film is placed on an A4 size copper foil base material Formed.
Thereafter, the copper foil base material on which the transparent conductive carbon film was formed was cut into 2 cm squares to prepare samples, and the respective samples were transferred in the same manner as in Example 1 and Example 2 (PET). And the resistivity (R) and transmittance (T) of the transparent conductive carbon film transferred to the transfer substrate were measured.

The resistivity and transmittance of the transferred transparent conductive carbon film were measured using a Lorester GP MCP-T600 resistivity meter and a Shimadzu UV3600 spectrophotometer, respectively. The results obtained from each sample are shown in Table 2 as the range from the highest value to the lowest value.
As shown in Table 2, it was found that both had low resistivity and high transmittance.

1: 1st roll 2: 2nd roll 3: Base material for growth 4: Film-forming process 5: Transparent conductive carbon film formed on the base material for copper foil growth 6: Peel strength by physical treatment Step of weakening 7: Step of weakening peel strength by chemical treatment 8: Substrate for transfer 9: Third roll 10: Fourth roll 11: Substrate for transfer / transparent conductive carbon film / growing base by roll press Process for producing a carbon film laminate with three layers of materials (pressure / heat application process)
12: Carbon film laminate in which three layers of transfer base material / transparent conductive carbon film / growth base material are stacked 13: peeling and transferring step 14: transparent conductive carbon film transferred onto the transfer base material DESCRIPTION OF SYMBOLS 101: Plasma generation chamber 102: Rectangular microwave waveguide with a slot 103: Quartz window for introducing a microwave 104: Metal support member which supports a quartz window 105: Base material (copper foil base material)
106: Sample stage for installing the base material 107: Cooling water supply / drain pipe 108: Exhaust pipe 109: Gas inlet pipe for CVD processing 110: Reaction vessel 111: Cooling water pipe

Claims (12)

  The transparent conductive carbon film formed on the growth base material by the CVD method is peeled off from the growth base material and transferred to the transfer base material to peel off the transparent conductive carbon film. Before, the manufacturing method of the transparent conductive carbon film characterized by having the process of weakening the peeling strength of the said base material for growth and a carbon film.   2. The method for producing a transparent conductive carbon film according to claim 1, wherein the step of weakening the peel strength sets the peel strength to 1 N / cm or less.   3. The method according to claim 1, wherein the step of weakening the peel strength is a step of giving a temperature difference of 200 ° C. or more for a predetermined time from 300 ° C. or lower to a low temperature to a high temperature or from a high temperature to a low temperature. A method for producing a transparent conductive carbon film.   4. The method for producing a transparent conductive carbon film according to claim 3, wherein the step of weakening the peel strength is a step of immersing in a liquid nitrogen solution.   The method for producing a transparent conductive carbon film according to claim 1, wherein the peeling step is a step of immersing in an acid or salt solution.   The method for producing a transparent conductive carbon film according to claim 5, wherein the aqueous acid solution is an aqueous sulfuric acid solution of 0.01 M or less.   The method for producing a transparent conductive carbon film according to claim 1, wherein the transparent conductive carbon film is graphene.   The method for producing a transparent conductive carbon film according to claim 1, wherein the CVD method is performed by a plasma CVD method at 500 ° C. or less.   The method for producing a transparent conductive carbon film according to claim 1, wherein the growth base material is a copper base material.   Using a roll-shaped growth substrate, forming a transparent conductive carbon film on the growth substrate by a CVD method, peeling the transparent conductive carbon film from the roll-shaped growth substrate, and transferring the substrate The method for producing a transparent conductive carbon film according to any one of claims 1 to 9, wherein after the transfer to the material, the substrate for transfer is continuously wound on a roll.   It is a carbon film laminated body obtained in the method of any one of Claims 1-10, Comprising: It has three layers of the base material for transcription | transfer / transparent conductive carbon film / base material for growth, A carbon film laminate, wherein the peel strength between the substrate and the transparent conductive carbon film is 1 N / cm or less.   A carbon film laminate obtained by the method according to any one of claims 1 to 10, wherein the carbon film laminate has a transparent conductive carbon film peel-transferred onto a transfer substrate.