JPH0638415B2 - Organic conductive medium and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an organic conductive medium and a method for manufacturing the same, and more particularly, an organic conductive layer of an organic conductive medium is patterned into a high conductive region and a low or non-conductive region. And a method for producing an organic conductive medium capable of easily providing the organic conductive medium.

(Prior Art) Conventionally, various conductive media such as various ICs and semiconductors have been known, and in most cases, a conductive inorganic substance is used as a material of a functional portion of these conductive media. However, as these conductive media are required to have higher precision, higher miniaturization, and higher integration, the use of conductive organic substances that are easy to handle and have many types as materials for functional parts such as semiconductor elements has been widely studied. There is.

An organic charge transfer complex is known as one of conductive organic substances. As a method for forming such an organic charge transfer complex as a uniform film on an arbitrary substrate, Langmuir Blodgett proposed by Langmuir et al. Method (LB method)
It has been known.

According to this LB method, a monomolecular film of an organic charge transfer complex having a hydrophobic site and a hydrophilic site in one molecule or a cumulative film thereof can be easily formed on a substrate. The thus formed organic conductive layer has a good conductivity in the horizontal direction of the film because the hydrophobic part having a high electrical insulation property and the hydrophilic part having a high conductivity are superposed in a multilayer form. And has a peculiar property of anisotropy of conductivity such that it has a high insulating property in the direction perpendicular to the film.

(Problems to be Solved by the Invention) The above organic conductive layer has extremely uniform conductivity in the plane direction of the layer, and various applications are expected. When the organic conductive medium having these organic conductive layers is used as various electric elements such as electric circuits, it is necessary to finely process the conductive layers into a desired pattern. As such a fine processing method,
For example, a method of forming and growing a conductive layer as described above on a substrate in a pattern has been considered, but the LB film as described above is a method of transferring a uniform monomolecular film spread on an aqueous phase onto the substrate. Since it is formed, the formation of such a patterned film has not yet reached a practical area.

As another method, a method of patterning the LB film once formed by post-treatment, for example, an etching method of removing a desired region of the film is considered, but this method is different from the chemical etching of the inorganic substance, There is a problem in that it is difficult to select a material, a mask method, an etching agent, etc., and there is a great possibility that even the conductive layer other than the etching region is deteriorated by the etching agent. In particular, the higher the density and the degree of integration of the organic conductive medium, the more difficult such microfabrication becomes, and therefore it is possible to take advantage of the excellent characteristics of the layer composed of the monomolecular film or cumulative film of the organic charge transfer complex. There is a problem that you cannot do it.

The conductivity of the LB film as described above is usually about 0.1 S / cm, which is very high as an organic substance, but is significantly smaller than that of conventional inorganic conductive materials such as gold, silver and copper. Therefore, there is a problem that the conductivity is insufficient.

Therefore, there is a demand for a technique capable of easily forming a highly precise and fine pattern in an organic conductive medium having a functional portion made of a conductive organic substance as described above without impairing the characteristics of these layers.

(Means for Solving Problems) As a result of earnest research to meet the demands of the prior art as described above, the present inventor has confirmed that the precision of a conductive layer made of a conductive organic substance and the characteristics thereof are not impaired. We have developed a technique that enables easy patterning of the organic conductive layer into a high conductive region and a low or non-conductive region of a desired pattern.

That is, the first invention of the present invention is an organic conductive medium characterized in that an organic conductive layer is formed on the surface of a substrate having a fine uneven shape, and the second invention is a fine uneven shape. A method for producing an organic conductive medium, characterized in that a monomolecular film of a conductive organic compound or a cumulative film thereof is laminated on the surface of the substrate.

Next, the present invention will be described in more detail.

That is, according to a detailed study by the present inventor, when an organic conductive layer is formed of a conductive organic compound on a substrate having a smooth surface, a substantially uniform conductivity is obtained in a direction parallel to the surface of the organic conductive layer. As shown in the figure, on the contrary, by forming a fine uneven shape on the substrate surface in advance and forming an organic conductive layer on the surface, the fine uneven shape is formed on the substrate along the uneven shape. The conductivity of the formed organic conductive layer is significantly improved or decreased, and the organic conductive layer is patterned into a high conductive region and a low or non-conductive region. Such a significant change in conductivity is due to the fact that when the organic conductive layer is transferred to a fine uneven surface, the orientation of the molecules forming the layer is significantly improved along the uneven shape, and the layer has an uneven shape. It is considered that the local conductivity or rearrangement of the membrane-constituting molecules occurs correspondingly to the change in the conductivity of the membrane.

Therefore, according to the present invention, it is possible to provide an organic conductive medium having a desired conductive pattern simply by forming a desired uneven shape on a substrate and then simply forming an organic conductive layer on the surface. And various drawbacks in the prior art,
That is, problems such as many complicated steps, use under severe conditions such as high temperature and high pressure, use of various chemicals, etc. can be easily solved, and an organic conductive medium having high density, high integration degree, etc. can be formed by very simple steps. Was provided.

As the conductive organic compound forming the organic conductive layer of the organic conductive medium of the present invention, any conventionally known conductive organic compound can be used, but a particularly preferred conductive organic compound is an organic charge transfer complex.

The preferred charge transfer complex used for forming the organic conductive layer in the present invention is a compound having a hydrophilic site, a hydrophobic site and a conductive site in one molecule.

Any conventionally known charge transfer complex having such a condition can be preferably used in the present invention, but a particularly preferable compound is that the hydrophilic moiety is a quaternary ammonium group,
The hydrophobic moiety is a hydrophobic hydrocarbon group such as an alkyl group, an aryl group, or an alkylaryl group, and the conductive moiety is a tetracyanoquinodimethane structure.

The compound preferable as the charge transfer complex is represented by the following general formula (I).

[A] [TCNQ] nXm (I) For example, the following compounds may be mentioned.

R in the above is a hydrophobic moiety and is an alkyl group, an aryl group or an alkylaryl group, and a preferable one is an alkyl group having 5 to 30 carbon atoms. R ₁ is a lower alkyl group, n and q are 0, 1 or 2, m is 0
Alternatively, it is 1 and X is an anion group such as halogen ion such as bromine ion or perchlorate ion. Y is oxygen or sulfur.

The compound as described above may further have a polymerizable group such as a double bond or a triple bond in the alkyl group, and may have 1 or more substituents on the heterocycle.
It may have one or more substituents such as an alkyl group, an alkenyl group, a cyano group, an alkoxy group and a halogen.

Further, TCNQ is a compound represented by the following formula.

It may have an arbitrary substituent such as an alkyl group, an alkenyl group and a halogen atom at positions a to d in the above formula.

The present inventor has earnestly studied charge transfer complexes including the above-exemplified compounds, and these charge transfer complexes are formed as a monomolecular film or a cumulative film thereof on a substrate having an arbitrary surface shape by a known method. When formed on a substrate having a smooth surface, such a monomolecular film or a cumulative film thereof is easy to form and has a high insulating property in the vertical direction of the film and a horizontal direction in the film. It has high conductivity and shows very excellent conductivity anisotropy, but it cannot be used as it is as an organic conductive medium for electric circuits, but as the above substrate, its surface is fine. When the organic conductive layer has a large unevenness, the conductivity of the film of these organic conductive layers changes significantly in the horizontal direction, and as a result of showing a difference in conductivity corresponding to the uneven shape of the substrate, various electrical elements are obtained. Useful and It was finding the Rukoto.

In the present invention, the LB method is a preferred method for forming a conductive layer on the surface of a substrate having an arbitrary uneven shape by using the above charge transfer complex.

The LB method is, for example, in a molecule having a structure having a hydrophilic site and a hydrophobic site in the molecule such as the above charge transfer complex, when the balance between them (the amphipathic balance) is appropriately maintained, This is a method for producing a monomolecular film or a cumulative film thereof by utilizing the fact that a molecule forms a monomolecular layer with a hydrophilic group facing downward on the water surface.

The monolayer on the water surface has the characteristic of a two-dimensional system. When the molecules are scattered, the area A per molecule and the surface pressure π
The two-dimensional ideal gas equation, πA = kT, holds between and and becomes a “gas film”. Here, k is the Boltzmann constant and T is the absolute temperature. If A is made sufficiently small, intermolecular interaction will be strengthened, and a two-dimensional solid "condensed film (or solid film)" will be formed. The condensation film can be transferred layer by layer to the surface of any object having various materials and shapes such as glass and resin.

Specific methods include, for example, the following methods.

The desired charge transfer complex is dissolved in a solvent such as chloroform, benzene or acetonitrile. Next, using a suitable apparatus as shown in FIG. 1 of the accompanying drawings, the solution of the charge transfer complex is spread on the aqueous phase 1 to form the charge transfer complex in the form of a film.

Next, a partition plate (or float) 3 is provided to prevent the spreading layer from freely diffusing over the water phase and spreading too much, limiting the spreading area to control the aggregation state of the membrane substance, and proportional to the aggregation state. The obtained surface pressure π is obtained. The partition plate 3 can be moved to reduce the development area to control the aggregated state of the membrane substances, gradually increase the surface pressure, and set the surface pressure π suitable for the production of the membrane. While maintaining this surface pressure, the monomolecular film of the charge transfer complex is transferred onto the substrate 2 by gently raising or lowering the clean substrate 2 vertically. Such a monomolecular film is a film in which molecules are arranged in an orderly manner as schematically shown in FIG. 2a or 2b.

Although the monomolecular film of the charge transfer complex is produced as described above, a desired cumulative number of cumulative films is formed by repeating the above-mentioned operation. To transfer the charge transfer complex monolayer onto the substrate,
In addition to the vertical dipping method described above, a horizontal attachment method, a rotating cylinder method, or the like is also possible.

The horizontal attachment method is a method of transferring the monomolecular film by horizontally contacting the substrate with the water surface, and the rotating cylinder method is a method of rotating the cylindrical substrate on the water surface to transfer the monomolecular film to the substrate surface. is there.

In the above-mentioned vertical immersion method, when a substrate whose surface is hydrophilic is pulled up from the water in a direction crossing the water surface, a monomolecular film of the charge transfer complex in which the hydrophilic groups of the charge transfer complex face the substrate is formed on the substrate. (Fig. 2b). When the substrate is moved up and down as described above, the monomolecular films are stacked one by one in each step to form a cumulative film. Since the directions of the film-forming molecules are opposite in the pulling up process and the dipping process, according to this method, the hydrophobic groups of the charge transfer complex and the hydrophobic groups face each other between the layers of the monomolecular film.
A mold film is formed (Fig. 3a). On the other hand, in the horizontal attachment method, a monomolecular film in which the hydrophobic groups of the charge transfer complex face the substrate is formed on the substrate (Fig. 2a). in this way,
Even if the monomolecular film is accumulated, there is no change in the direction of the film-forming molecules, and in all the layers, an X-type film in which the hydrophobic group faces the substrate is formed (Fig. 3b). On the contrary, a cumulative film in which hydrophilic groups in all layers face the substrate is called a Z-type film (3c).
Figure).

The method of transferring the monomolecular film onto the substrate is not limited to the above method, and when a large-area substrate is used, a method of extruding the substrate from a roll into the aqueous phase may be employed. Further, the orientations of the hydrophilic group and the hydrophobic group described above to the substrate are in principle, and can be changed by surface treatment of the substrate.

As described above, the conductive layer composed of the monomolecular film of the charge transfer complex or its accumulated film is formed on the substrate.

In the present invention, the substrate for forming the organic conductive layer composed of the monomolecular film of the charge transfer complex or the cumulative film thereof as described above may be any material such as metal, glass, ceramics, plastic material, etc. Remarkably low biomaterials can also be used. A conductive material such as a metal can be used because, as described above, the monomolecular film or the cumulative film has a sufficient insulating property in the direction perpendicular to the film.

The substrate as described above may have any shape and is preferably a flat plate, but is not limited to a flat plate. That is, the present invention has an advantage that a film can be formed according to any shape of the surface of the substrate.

At least a part of the surface of the substrate as described above has a fine uneven shape of an arbitrary shape, and such an uneven shape can be formed by any conventionally known method. For example, when the substrate is made of synthetic resin, a method of transferring the uneven shape using a mold having a desired fine uneven surface, when the substrate is a metal or ceramic,
In the photo-etching method generally used in conventional printing plate technology and IC technology, a photosensitive resin layer is formed on the desired surface of the above-mentioned substrate and other substrates, exposed through a mask pattern, developed, and exposed to light. Any method such as a method of forming an uneven shape depending on the thickness of the resin layer can be used. Further, it is preferable that the formed irregularities have continuity such as a linear shape, a curved shape or a combination thereof. Further, in these uneven shapes, particularly in the case of linear or curved uneven shapes, when the spacing between the lines, that is, the pitch width is too wide, a difference in conductivity of the organic conductive layer formed thereon occurs. Since it is difficult to do so, the pitch width of them is 0.1
About 100 μm is preferable.

Further, the shapes of the concave and convex portions having the linear uneven shape as described above, that is, the shapes of the valleys and the peaks are not particularly limited. However, if the difference in height between them, that is, the depth of the groove is too shallow, the difference in conductivity as described above becomes small. Therefore, a depth of about 0.1 to 100 μm is generally preferable.

The conductive medium of the present invention is provided by forming an organic conductive layer on the surface of a substrate having the above-mentioned uneven shape by the method as described above. When the charge transfer complex used has a polymerizable group, It is also possible to remarkably improve the film strength by polymerizing and hardening these films after forming the films as described above.

Further, as described above, the organic conductive medium of the present invention has a conductive layer patterned into a highly conductive region and a non-conductive region. As a result, a metal such as gold, silver, copper or nickel is formed on the surface as a cathode. It is also possible to form a plating layer corresponding to the conductive pattern by plating with. By doing so, the allowable electric capacity and heat resistance of the conductive medium can be significantly improved.

(Operation / Effect) According to the present invention as described above, it is only necessary to adopt a substrate having a desired fine uneven shape as the substrate of the conductive medium, and the organic conductive layer is subjected to severe conditions such as particularly high temperature, pressure or light. Or various acids, alkali, since it is possible to impart a desired conductive pattern without using a strong agent such as an organic solvent, without damaging the excellent characteristics of the conductive organic compound used, high A high-performance conductive medium having high density and high integration is provided.

Further, according to the present invention, in forming the conductive pattern,
Since it is not necessary to destroy the organic conductive layer on the substrate, it is possible to form any conductive pattern without adversely affecting the organic conductive layer, which enables high-fine processing and excellent electrical It has become possible to easily provide an organic conductive medium having characteristics with good reproducibility.

From the above points, according to the present invention, the organic conductive medium of the present invention can be expected not only as a conventional high-density electric element but also as a bioelectronic element utilizing a living body.

Next, the present invention will be described more specifically with reference to examples.

Example 1 A photoresist material OMR is formed on an i-type crystalline silicon wafer.
(Manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied and dried to a thickness of 1.5 μm.

Next, after exposing through a photomask, developing, and then etching treatment is performed to form stripe-shaped grooves (groove width 1.6 μm).
m, a depth of 1.5 μm, and a groove-to-groove spacing of 5 μm).

The charge transfer complex (1) was dissolved in a mixed solvent of benzene-acetonitrile (volume ratio 1: 1) at a concentration of 1 mg / m, and then CdCl ₂ concentration was adjusted to pH 6.8 with KHCO ₃ and the concentration was 4 × 10 4.
^It was developed on the water phase at ^-4 mol /, water temperature 17 ° C.

After removing the solvents acetonitrile and benzene by evaporation,
The surface pressure was increased to 20 dyne / cm to form a monomolecular film. While keeping the surface pressure constant, the above silicon wafer is gently immersed in the direction across the water surface at a speed of 3 mm / min, and then gently pulled up at a speed of 3 mm / min to form a two-layer monomolecular film on the substrate. Accumulated in terms of. The above accumulation operation was repeated again to obtain an organic conductive medium of the present invention in which four layers of monomolecular films were laminated.

An electrode was provided on the organic conductive medium of the present invention obtained as described above, and the conductivity between two points on a continuous groove was measured.
It was about 10 ² S / cm. On the other hand, the electric conductivity between the independent grooves was 10 ⁻⁵ S / cm or less at any point, showing extremely large electric conductivity anisotropy.

Examples 2 to 9 Groove width (μm) of stripe-shaped unevenness in Example 1
Various organic conductive media of the present invention were prepared in the same manner as in Example 1 except that the cumulative number of monolayers and monolayers were as shown in Table 1 below, and the grooves thereof were formed in the same manner as in Example 1. 2 along
The conductivity between the points and the conductivity between the two points intersecting the groove were measured, and the results shown in Table 1 below were obtained.

Examples 10 to 12 Various organic conductive media of the present invention were obtained in the same manner as in Example 1 except that the charge transfer complexes shown in Table 2 below were used in place of the charge transfer complexes in Example 1. When the conductivity of these organic conductive media was measured in different directions, the results shown in Table 2 below were obtained.

The charge transfer complex has the following structure.

Example 13 Using the organic conductive layer of the organic conductive medium of the present invention obtained in Example 1 as a cathode, an aqueous copper sulfate solution (copper sulfate 200 g /, sulfuric acid 50 g /
), The temperature is 20 to 30 ° C., and the cathode current density is 0.5 to
Copper electroplating was carried out under the condition of 1.5 A / dm ² , and a plating layer having a thickness of 3 μm was formed along the groove to obtain an organic conductive medium of the present invention.

The conductivity between two points along the groove of this organic conductive medium is 10 ⁴
S / cm, and the conductivity between two points intersecting the groove is 10
It was ^-2 S / cm.

Comparative Example A conductive medium was obtained in the same manner as in Example 1 except that the substrate having a smooth surface was used in Example 1. The conductivity between any two points of this conductive medium was about 10 ³ S / cm in any case regardless of the direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a method for forming an organic conductive layer of a conductive medium of the present invention. FIG. 2 is a schematic diagram of a monomolecular film, and FIG. 3 is a schematic diagram of a cumulative film. FIG. 4 is a diagram schematically showing a cross section of the conductive medium of the present invention. 1; Aqueous phase 2; Substrate 3; Float 4; Monolayer film 5; Cumulative film 6; Hydrophilic part (conductive part) 7; Hydrophobic part 8; Recessed part 9; Convex part 10; Organic conductive layer 11; Electrode

 ─────────────────────────────────────────────────── (72) Inventor Haruki Kawata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshinori Tomita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Hiroshi Matsuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. An organic conductive medium comprising an organic conductive layer formed on the surface of a substrate having fine irregularities. 2. The organic conductive layer is a monomolecular film of an organic charge transfer complex having a hydrophobic site, a hydrophilic site and a conductive site in one molecule or a cumulative film thereof.
The organic conductive medium according to item (1). 3. The organic electroconductive medium according to claim 1, wherein the organic charge transfer complex is a complex of a quaternary ammonium compound and tetracyanoquinodimethane. 4. A method for producing an organic conductive medium, which comprises laminating a monomolecular film of a conductive organic compound or a cumulative film thereof on a surface of a substrate having fine irregularities.