JP2004039846A - Conductive path or electrode, and method for forming the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply forming a conductive path or an electrode with high manufacturing efficiency with high resolution and positional accuracy. <P>SOLUTION: The method for forming the conductive path or the electrode includes steps of forming a metal fine particle containing layer containing metal fine particles each having a mean particle size of 50 nm or less and in a state that metal fine particles are isolated from each other by an organic material on a support, and heating the layer in a target shape to heat and fusion-bond the metal fine particles. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for forming a conductive path or an electrode, and more particularly to a method for forming a conductive path or an electrode used for a semiconductor device using a metal fine particle dispersion.
[0002]
[Prior art]
In recent years, as a semiconductor element, a new method for manufacturing a conductive path and an electrode used for an organic thin film transistor has been proposed. For example, WO 01/47043, WO 00/79617, and Japanese Patent Application Laid-Open No. H11-274671 disclose techniques for directly forming conductive paths and electrodes by ink jet. However, the production efficiency is low and the technique is not suitable for mass production. Met.
[0003]
JP-A-2000-239853, JP-A-2001-35814, and the like disclose a technique of forming a conductive metal thin film by applying a liquid in which metal fine particles are dispersed and performing heat fusion. Among these, although a method of forming a metal thin film and then patterning by a normal etching process is described, a complicated process such as a resist formation and an etching process is required, and the production efficiency is high. There was no one. Japanese Patent Application Laid-Open No. 2000-239853 describes a method of forming a dispersion of fine metal particles by screen printing. However, in a printing method including screen printing, patterning with low resolution and high positional accuracy is difficult. there were.
[0004]
It has been strongly desired to provide a method for forming conductive paths and electrodes that is simple, has high resolution, has high positional accuracy, and has high manufacturing efficiency.
[0005]
[Problems to be solved by the invention]
That is, an object of the present invention is to provide a method for forming a conductive path or an electrode that is simple, has high manufacturing efficiency, and has high resolution and positional accuracy.
[0006]
[Means for Solving the Problems]
The above problem has been solved by the following configuration.
[0007]
(1) Forming a metal fine particle-containing layer containing metal fine particles having an average particle diameter of 50 nm or less on a support, wherein the metal fine particles are separated by an organic substance, and heating the metal to a desired shape. A method for forming a conductive path or an electrode, comprising heating and fusing fine particles.
[0008]
(2) The method for forming a conductive path or an electrode according to (1), wherein the heating is performed by a thermal head.
[0009]
(3) The method for forming a conductive path or an electrode according to (1) or (2), wherein a protective layer is provided on the metal fine particle-containing layer.
[0010]
(4) The method according to any one of (1) to (3), wherein, after heating and fusing in a desired shape, the metal fine particle-containing layer in the unheated portion is removed together with the protective layer using a developer. Forming method of the conductive path or the electrode.
[0011]
(5) The conductive path or the conductive path according to any one of (1) to (3), wherein, after being heat-fused in a desired shape, the metal fine particle-containing layer in the non-heated portion is peeled off together with the protective layer. Method of forming electrodes.
[0012]
(6) The method for forming a conductive path or electrode according to (4) or (5), wherein a post-heating treatment is performed.
[0013]
(7) The method for forming a conductive path or an electrode according to (1), wherein the heating is performed by high-density energy light.
[0014]
(8) The method of (7), wherein the high-density energy light is infrared light having a wavelength of 700 nm or more.
[0015]
(9) The method according to (7) or (8), wherein the high-density energy light is laser light.
[0016]
(10) The method for forming a conductive path or an electrode according to any one of (7) to (9), wherein an ablation preventing layer is provided on the metal fine particle-containing layer.
[0017]
(11) The method for forming a conductive path or an electrode according to any one of (7) to (10), further comprising a layer containing a photothermal conversion agent.
[0018]
(12) The method according to any one of (7) to (11), wherein, after heating and fusing in a desired shape, the metal fine particle-containing layer in the non-heated portion is removed together with the ablation preventing layer using a developer. The method for forming the conductive path or the electrode according to the above.
[0019]
(13) The conductive path according to any one of (7) to (11), wherein, after being heat-fused in a desired shape, the metal fine particle-containing layer in the non-heated portion is peeled off together with the ablation preventing layer. Alternatively, a method for forming an electrode.
[0020]
(14) The method for forming a conductive path or an electrode according to (12) or (13), wherein a post-heating treatment is performed.
[0021]
(15) The method for forming a conductive path or an electrode according to any one of (12) to (14), wherein a dry etching process is performed on the formed surface.
[0022]
(16) A conductive path or electrode formed by the method for forming a conductive path or electrode according to any one of (1) to (15).
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 shows an example of a heating method using a thermal head to heat-bond metal fine particles to a target conductive path or an electrode shape (hereinafter, sometimes simply referred to as a target shape). FIG. 3 is a diagram illustrating a method of forming a conductive path.
[0025]
FIG. 1A shows a state in which a metal fine particle-containing layer 4 is formed on a support 3 and a protective layer 2 is further laminated thereon. The metal fine particles in the containing layer 4 are thermally fused to form a conductive path or an electrode 8.
[0026]
In this state, a via hole is opened from the support or the protective layer side, and arbitrary joining to the circuit element can be performed with solder or the like. Further, in FIG. 1B, when the protective layer is peeled off, the unheated portion of the metal fine particle-containing layer is also peeled off at the same time, so that only the patterned conductive path or electrode 8 can be left on the surface of the support. Also, using a dissolvable material for the protective layer, the protective layer is removed by development with an aqueous solution to which a solvent, water or, if necessary, a surfactant, an organic solvent, an acid, or an alkali is added. The containing layer can also be removed, leaving only the similarly patterned conductive paths or electrodes 8 on the support surface.
[0027]
FIG. 2 is a view showing a method of forming an electrode or a conductive path by heat fusion by a photothermal conversion method.
[0028]
In FIG. 2A, a metal fine particle-containing layer 4 is provided on a support 3, and an ablation preventing layer 10 is further laminated thereon. By irradiating a pattern with a laser beam in a desired shape, the metal fine particles in the metal fine particle-containing layer 4 are thermally fused to form conductive paths or electrodes 8 in the desired shape. Thereafter, similarly to the method using the thermal head of FIG. 1, the abrasion preventing layer may be peeled off as shown in FIG. The conductive path or the electrode 8 may be formed on the support by development with water or an aqueous solution to which a surfactant, an organic solvent, an acid, an alkali or the like is added as required.
[0029]
FIGS. 3C to 3G show various examples in which the ablation preventing layer 10 and the light-to-heat conversion layer 9 are used in combination. FIG. 3C shows a light-heat conversion layer 9 provided on a support 3, a metal fine particle-containing layer 4 formed thereon, and an ablation prevention layer 10 provided thereon. A metal fine particle-containing layer 4 is formed on a support 3, a photothermal conversion layer 9 is provided thereon, and an ablation prevention layer 10 is provided thereon. FIG. FIG. 7 (f) shows the case where the photothermal conversion agent 9 ′ is contained in the metal fine particle-containing layer, and FIG. 7 (g) shows the case where both the ablation preventing layer and the metal fine particle-containing layer are contained. It contains a light-to-heat conversion agent 9 ', and the various configurations described above can be used in the present invention.
[0030]
Further, as another form, as shown in FIG. 2H, the support and the ablation preventing layer are not integrated, and one of the supports 3 is provided with a light-to-heat conversion layer 9 and the other is ablation preventing layer 10. Is provided with a metal fine particle-containing layer 4, and the support 3 and the ablation preventing layer 10 are brought into close contact with each other so that the light-to-heat conversion layer 9 and the metal fine particle-containing layer 4 are in contact with each other, and irradiated with high illuminance light to obtain a target shape. As described above, a method of forming a conductive path or an electrode 8 on the support body side by thermally fusing the metal fine particles and peeling them off from each other can also be used.
[0031]
The metal fine particle-containing layer according to the present invention is a layer formed by using a dispersion containing metal fine particles having a particle diameter of 1 to 50 nm, preferably 1 to 10 nm, and the space between the metal fine particles is substantially formed. Although it does not exhibit conductivity in a state of being isolated by an organic substance, it is characterized in that metal particles are thermally fused by heating to form a conductive path or an electrode. Use platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, zinc, etc. Can be.
[0032]
The fine metal particle-containing layer is formed by using a dispersion liquid in which fine particles composed of these metals are dispersed in water or a dispersion medium that is an arbitrary organic solvent using a dispersion stabilizer mainly composed of an organic material.
[0033]
As a method for producing such a metal fine particle dispersion, a metal ion is reduced in a liquid phase, such as a physical generation method such as a gas evaporation method, a sputtering method, a metal vapor synthesis method, a colloid method, and a coprecipitation method. A chemical production method for producing metal fine particles may be mentioned, and preferably, a colloid method described in JP-A-11-76800, JP-A-11-80647, JP-A-11-319538, JP-A-2000-239853, etc. It is a metal fine particle dispersion produced by the in-gas evaporation method described in JP 2001-254185, JP 2001-53028, JP 2001-35255, JP 2000-124157, JP 2000-123634 and the like. After forming a layer by using these metal fine particle dispersions and drying the solvent, the metal fine particles are heated by the method of the present invention in the range of 100 to 300 ° C, preferably 150 to 200 ° C. To form a conductive path or an electrode having a desired shape.
[0034]
As the support used in the present invention, any material such as glass, bakelite and a flexible plastic film can be used. Examples of the plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide, polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose. Examples include films made of triacetate (TAC), cellulose acetate propionate (CAP), and the like. By using such a plastic film, weight reduction can be achieved, flexibility can be increased, and portability can be increased. The softening point is preferably 150 ° C. or higher, more preferably 200 ° C. or higher.
[0035]
In the heating method using a thermal head, it is preferable to provide a protective layer to prevent fusion between the metal fine particle-containing layer and the head. Examples of the material for the protective layer include ABS resin, polyethylene terephthalate (PET) film, polyethylene naphthalate. (PEN) various plastic films such as films, films made of various ceramics, films formed by applying a resin solution or dispersion, thermosetting resins, electron beam curable resins, ultraviolet curable resins, etc. Various materials such as a film using a curable resin can be used.
[0036]
In the photothermal conversion method, it is preferable to provide an ablation preventing layer for preventing ablation of the metal fine particle-containing layer when performing scanning exposure or flash exposure with high-density energy light, and is substantially 1 μm or more, preferably 2 μm. The above resin layer is preferable. For example, a resin having a Young's modulus of 150 kg / mm ² or more and a breaking elongation of 20% or more can be used. Specifically, polyvinyl alcohol, a novolak resin, an acrylic resin, or the like can be used, and a film used for the protective layer or the support may be used.
[0037]
As the light-to-heat conversion agent used in the light-to-heat conversion layer, a conventionally known near-infrared light absorber can be used, for example, cyanine, polymethine, azurenium, squalium, thiopyrylium, naphthoquinone, anthraquinone dye Organic compounds such as phthalocyanine, azo, and thioamide are preferably used. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, 1-280750, 1-293342, 2-2074, 3-26593, 3-30991, 3-34891, 3-36093, 3-36094, and 3 And compounds described in JP-A-36095, JP-A-3-42281, JP-A-3-97589 and JP-A-3-103476. These can be used alone or in combination of two or more. Further, carbon black and the like are also preferable. The light-to-heat conversion layer can be obtained by dispersing or dissolving these light-to-heat conversion agents in a resin solution, coating and drying, or kneading and stretching the light-to-heat conversion agent in a resin to form a film.
[0038]
As a coating method of the composition of each layer, a known coating method such as dipping, spin coating, knife coating, bar coating, blade coating, squeeze coating, reverse roll coating, gravure roll coating, curtain coating, spray coating, and die coating is used. A coating method capable of performing continuous coating or thin film coating is preferably used.
[0039]
High illuminance light is used as a light source for the light-to-heat conversion method. However, there is no particular limitation as long as it can be heated to a temperature at which metal fine particles are thermally fused by heat in the light-to-heat conversion layer. Although a laser beam is preferably used, flash exposure using a xenon lamp, a halogen lamp, a mercury lamp, or the like may be performed through a mask. In the case of laser light, it is possible to perform a scanning exposure according to the purpose by narrowing down the beam shape, and further, since the exposure area can be easily narrowed down to a minute size and a high-resolution image can be formed. It can be suitably used.
[0040]
In order to obtain high resolution by exposure with a laser beam, an electromagnetic wave whose energy application area can be narrowed down, in particular, an ultraviolet ray having a wavelength of 1 nm to 1 mm, a visible ray, or an infrared ray is preferable. known, ruby laser, YAG laser, solid state laser glass laser,; the He-Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, the He-Cd laser, _{N 2} laser, excimer laser, etc. gas laser; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, a semiconductor laser such as GaSb laser; chemical laser, there may be mentioned a dye laser or the like, the wavelength among these 700~1200nm The use of infrared lasers Because it can efficiently convert the thermal energy of Energy, preferred in terms of sensitivity.
[0041]
An infrared laser having an output per laser beam of 20 to 200 mW is most preferably used. It is the energy density, preferably 50 to 500 mJ / cm ^2, more preferably a 100~200mJ / cm ^2.
[0042]
The direction of pattern irradiation with the laser beam may be from the ablation prevention layer side or the support side.
[0043]
In order to further enhance the fusion between the metal fine particles and improve the conductivity, it is preferable to remove the unheated portion after heating, and then to perform a post-heating treatment. Is 1 to 30 minutes, particularly preferably 5 to 10 minutes.
[0044]
Even after heat fusion, organic components such as particle dispersants may remain on the surface of the support or the surface of the heat-fused conductive path, which may result in insufficient bonding to other elements by soldering or the like. In addition, when used as an electrode of a TFT or the like, there is a problem that an organic semiconductor channel and a barrier are generated, and charge injection is hindered. For this reason, it is preferable to perform washing for removing the organic components after forming the electrodes. Although a method of treating with a cleaning agent having high solubility or dispersibility of an organic component may be used, in the present invention, treatment by dry etching such as plasma treatment is preferable. Further, oxygen plasma treatment is effective, and oxygen plasma treatment by an atmospheric pressure plasma method is particularly preferable.
[0045]
Even after heat fusion, organic components such as particle dispersants may remain on the surface of the support or the surface of the heat-fused conductive path, which may result in insufficient bonding to other elements by soldering or the like. When used as an electrode of a TFT or the like, there is a possibility that an organic semiconductor channel and a barrier may be formed, and a problem that charge injection is inhibited may occur. For this reason, it is preferable to perform washing for removing the organic components after forming the electrodes. Although a method of treating with a cleaning agent having high solubility or dispersibility of an organic component may be used, in the present invention, treatment by dry etching such as plasma treatment is preferable. Further, oxygen plasma treatment is effective, and oxygen plasma treatment by atmospheric pressure plasma discharge is particularly preferable.
[0046]
Atmospheric pressure plasma discharge is to perform a surface treatment with an excited active species generated by generating a plasma discharge at or near atmospheric pressure with respect to vacuum plasma discharge performed under reduced pressure. The feature is that the treatment efficiency is good because the concentration of the excited active species can be increased, but in the present invention, near atmospheric pressure means 1.013 × 10 ² ± 0.507 × 10 ² kPa, preferably 1. The range is 013 × 10 ² ± 0.304 × 10 ² kPa, and more preferably the range is 1.013 × 10 ² ± 0.203 × 10 ² kPa.
[0047]
【Example】
EXAMPLES The present invention will be specifically described by way of examples, but the present invention is not limited thereto.
[0048]
Example 1
An ethanol dispersion of fine gold particles having an average particle diameter of about 10 nm was applied on a polyimide film support, and dried at 50 ° C. to form a metal fine particle-containing layer having a thickness of 0.2 μm. On this, a polyvinyl alcohol layer having a thickness of 2 μm was provided as an ablation preventing layer. Exposure was performed from a semiconductor laser having an output wavelength of 830 nm and an output of 50 mW at an energy density of 200 mJ / cm ² and a writing resolution of 4000 dpi (where dpi represents the number of dots per 2.54 cm) to fuse gold fine particles. . Thereafter, water development was performed to form a conductive path having a width of about 7 μm, and the conductivity was good.
[0049]
Example 2
A novolak resin layer (1 μm) containing 20% by mass of carbon black was provided as a photothermal conversion layer on a PES film support, and an aqueous dispersion of gold fine particles having an average particle diameter of about 10 nm (nonionic surfactant 0.1 μm) was formed thereon. (Containing 1%) and dried at 50 ° C. An ablation prevention layer made of polyvinyl phenol having a thickness of 2 μm was provided on the gold fine particle-containing layer having a thickness of 0.2 μm. Exposure was performed with a writing resolution of 400 dpi at an energy density of 200 mJ / cm ² from a semiconductor laser having an output wavelength of 830 nm and an output of 50 mW, and the gold fine particles were heated and fused. Thereafter, by conducting development using an aqueous solution of potassium silicate (pH 12) having a silicic acid content of 0.5%, a conductive path having a width of about 7 μm was formed, and the conductivity was good.
[0050]
【The invention's effect】
According to the method of the present invention, conductive paths and electrodes having high resolution and high positional accuracy can be provided by a simple forming method.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a method of forming an electrode or a conductive path using a thermal head as a heating method.
FIG. 2 is a diagram showing a method of forming an electrode or a conductive path by heat fusion by a photothermal conversion method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Thermal head 2 Protective layer 3 Support 4 Metal fine particle containing layer 8 Conductive path or electrode 9 Light-to-heat conversion layer 9 'Light-to-heat conversion agent 10 Ablation prevention layer

Claims (16)

A metal fine particle containing layer having an average particle diameter of 50 nm or less is formed on a support, and the metal fine particles are separated by an organic material. The metal fine particles are heated by heating in a desired shape. A method for forming a conductive path or an electrode, characterized by fusing. 2. The method according to claim 1, wherein the heating is performed by a thermal head. The method for forming a conductive path or an electrode according to claim 1, further comprising a protective layer on the metal fine particle-containing layer. The conductive path or the electrode according to any one of claims 1 to 3, wherein the metal fine particle-containing layer in the non-heated portion is removed together with the protective layer using a developer after the heat-fusing in a desired shape. Formation method. The method for forming a conductive path or an electrode according to any one of claims 1 to 3, wherein the metal fine particle-containing layer in a non-heated portion is peeled off together with the protective layer after being heat-fused in a desired shape. The method for forming a conductive path or an electrode according to claim 4, wherein a post-heating treatment is performed. The method for forming a conductive path or an electrode according to claim 1, wherein the heating is performed by high-density energy light. The method for forming a conductive path or an electrode according to claim 7, wherein the high-density energy light is infrared light having a wavelength of 700 nm or more. 9. The method according to claim 7, wherein the high-density energy light is laser light. The method for forming a conductive path or an electrode according to any one of claims 7 to 9, wherein an ablation preventing layer is provided on the metal fine particle-containing layer. The method for forming a conductive path or an electrode according to any one of claims 7 to 10, further comprising a layer containing a photothermal conversion agent. The conductive path or the conductive path according to any one of claims 7 to 11, wherein the metal fine particle-containing layer in a non-heated portion is removed using a developer together with the ablation preventing layer after the heat-fusing in a desired shape. Method of forming electrodes. The method for forming a conductive path or an electrode according to any one of claims 7 to 11, wherein after heating and fusing in a desired shape, the metal fine particle-containing layer in an unheated portion is peeled off together with the ablation preventing layer. . 14. The method for forming a conductive path or an electrode according to claim 12, wherein a post-heating treatment is performed. The method for forming a conductive path or an electrode according to claim 12, wherein a dry etching process is performed on the formed surface. A conductive path or electrode formed by the method for forming a conductive path or electrode according to claim 1.

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