KR20070086536A - Conductive pattern forming apparatus - Google Patents

Abstract

A conductive pattern forming apparatus using electrostatic force, by which high productivity, application to a large area and pattern change availability are achieved, without limiting a substrate nor increasing extra steps of plating and the like, with easy steps, lower cost, shorter manufacturing time and less environmental load. The conductive pattern forming apparatus is provided with an electrostatic latent image forming means for forming an electrostatic pattern on a dielectric thin film surface, and a developing means for forming the conductive pattern by development by supplying a conductive particle dispersed solution to the electrostatic latent image and bringing the solution into contact with the electrostatic latent image. The conductive particle dispersed solution is provided by dispersing conductive particles, which have ionic organic molecules adsorbed on the surface and a particle diameter of 100nm or less, in a nonpolar solvent.

Description

Conductive pattern forming device {CONDUCTIVE PATTERN FORMING APPARATUS}

The present invention relates to a forming apparatus for forming a conductive pattern on a printed board.

Conventionally, as a method of forming an arbitrary conductive pattern on a circuit board etc., the method which combined the lithography technique, the etching technique, and the plating technique was common. However, this method takes time to design and manufacture, requires an exposure mask that requires advanced processing techniques, and also requires a long preparation time and a high cost because a series of processes are complicated. Therefore, when the mask needs to be modified, such as small quantity production of many kinds, it was a problem to increase the cost or delay the delivery date. In addition, since the use of a large amount of environmentally harmful substances such as resists and etching liquids is indispensable, waste management and disposal are expensive.

On the other hand, as a method of easily forming a conductive pattern, a screen printing method in which a pattern is formed by passing a plated mesh using a conductive paste in which conductive particles and a binder resin are dispersed in a solvent, and a dispenser using a conductive paste likewise The direct drawing method which forms pattern directly to a board | substrate by nozzle scanning, such as inkjet technology, is proposed.

However, in screen printing, it is hard to say that the printing of printing screens, which are essential for pattern formation, is difficult. Therefore, when producing small quantities of various kinds that require a lot of pattern changes, a large amount of screen making is required. Augmentation was a challenge. In addition, since the screen itself becomes a waste, the cost of its management and disposal was also a problem. On the other hand, direct drawing methods such as dispensers and inkjets also draw inorganic material patterns directly onto the substrate by scanning the nozzles, resulting in a very long printing time, which makes it difficult to cope with mass production or large-area pattern formation. not.

For this reason, as a new method of forming a conductive pattern, a method of forming a desired conductive pattern on an insulating substrate using an electrostatic force using a toner having conductive metal particles embedded in a resin has attracted attention (see Patent Document 1, for example). . Since this method is close to printing, it is not only able to cope with mass production and large area pattern formation, but also can easily change the conductive pattern, and therefore, it is also suitable for small quantity production of many kinds.

However, in this method, since conductive metal particles serving as conductive materials are embedded in the toner and used, an insulating resin component, which is a toner binder, is interposed between the conductive metal particles to realize a resistance value required for a conventional circuit board.

As a countermeasure for the above problem, for example, Patent Document 1 considers a method of removing a binder resin by high temperature firing using a ceramic green sheet as a substrate. Moreover, in patent document 2, the method of forming wiring using electroconductive metal particle as a plating nucleus is examined.

[Patent Document 1]

Japanese Patent Application Laid-Open No. 2004-184598

[Patent Document 2]

Japanese Laid-Open Patent Publication No. 2004-48030

In the method of the said patent document 1, since a sufficient resistance value was not acquired as a wiring circuit, and since it was limited to the board | substrate with high heat resistance like ceramics, resin substrates with low heat resistance, such as an epoxy resin, could not be applied.

Moreover, in the method of patent document 2, processes, such as removal of a resin layer and plating, become essential and there existed a problem that preparation time and cost increase.

SUMMARY OF THE INVENTION The present invention has been made to realize a conductive pattern forming apparatus by a novel method that solves such problems, and the process is simple without increasing a new process such as limiting a substrate or plating, and thus costs, manufacturing time, and environmental load. It is an object of the present invention to provide a conductive pattern forming apparatus using less electrostatic force which is less, has high productivity, can cope with a large area, and the pattern can be easily changed.

In order to achieve the above object, the present invention provides a conductive pattern forming means including electrostatic latent image forming means for forming an electrostatic pattern on the surface of the dielectric thin film, and developing means for developing a conductive pattern by supplying a conductive particle dispersion solution to the electrostatic latent image on the electrostatic latent body. In the apparatus, the conductive particle dispersion solution is characterized in that the conductive particles having a particle diameter of 100 nm or less on which the ionic organic molecules are adsorbed on the surface are dispersed in the nonpolar solvent.

According to the conductive pattern forming apparatus of the present invention, the process is simple without increasing the new process such as limiting the substrate and plating, and the cost, production time and environmental load are small, high productivity, large area, and easy patterning. A changeable conductive pattern forming apparatus can be realized.

1 is a schematic view of a conductive pattern forming apparatus in the present invention,

Figure 2 is a schematic diagram of the conductive particle dispersion solution in the present invention,

3 is a schematic diagram of a conductive particle having a low molecular weight ionic organic molecule,

4 is another embodiment of the conductive pattern forming apparatus of the present invention.

※ Explanation of code for main part of drawing

1: charging means 2: electrostatic latent image

3: exposure means 4: dielectric thin film

5: latent electrostatic image pattern 6: developing means

7: conductive particle dispersion solution 8: substrate

9 transfer means 10 residual latent image erasing device

11: residual conductive particle cleaning device 12: conductive particle pattern

13 heating means 14 conductive pattern

15 nonpolar solvent 16 ionic organic molecule

17 conductive particles 18 inorganic ions

19: fatty acid ion 20: mask

21: conductive thin film layer

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described in detail.

(Example 1)

1 schematically shows an example of the conductive pattern forming apparatus of the present invention. This apparatus mainly uses a charging device 1 for equally charging the surface of the dielectric thin film 4 that forms the drum-shaped photosensitive member, and an electrostatic latent image by irradiating light to the surface of the dielectric film 4 that is equally charged. The exposure apparatus 3, the developing apparatus 6 having the conductive particle dispersion solution 7 therein for developing the conductive particles by attaching the conductive particles to the latent electrostatic image, and the transfer apparatus transferring the developed image to the substrate 8. (9) and a heating device 13 for heating and melting the phase on the substrate 8 to fix it to the substrate 8.

As the means for forming the latent electrostatic image of the present invention, the dielectric thin film 4 has a photosensitive property. As the charging device 1 which charges the surface of the dielectric thin film 4 equally, one of a corotron charge, a roller contact charge, a brush contact charge and the like are used. The surface of the dielectric thin film 4 is equally charged by the charging device 1. Thereafter, light is irradiated to an arbitrary portion of the surface of the dielectric thin film 4 by an exposure apparatus 3 that scans laser light in accordance with an image signal from an image information processing apparatus such as a personal computer to produce a desired electrostatic latent image 5. Form. In addition, an electrostatic charge is applied to the convex portion of the electrostatic latent image transfer member which has processed the desired pattern shape on the surface in advance without using the charging device 1 or the exposure apparatus 3 by laser light, and this is applied to the dielectric thin film 1 There is also a method of forming a desired electrostatic latent image 5 by stamp charging to be brought into contact with the surface. However, the stamp charging has a disadvantage in that the electrostatic latent image to be formed cannot be simply changed because the mold is used. In order to realize the easy change of the electrostatic latent image 5, it is preferable to use the electrostatic latent image pattern 5 formation method by exposure of the formerly electrostatic latent electrostatic image 2. In addition, the electrostatic latent image provided also in either method may be based on either positive or negative charge.

In the developing apparatus 6 of the present invention, the conductive particle dispersion solution 7 is contacted and supplied to the electrostatic latent image 5 formed on the surface of the dielectric thin film 4 to develop and form a conductive pattern with conductive particles. Therefore, the developing apparatus 6 includes a storage tank for storing the conductive particle dispersion solution 7 and a supply means for supplying the electrostatic latent image 5 on the dielectric thin film 4. In addition, although not shown in the figure, a concentration detecting means for detecting the concentration of the conductive particle dispersion solution 7 is provided in the storage tank. On the basis of the concentration information obtained by this concentration detecting means, a concentration adjusting means for adjusting the concentration is provided by adding the nonpolar solvent 15 or the conductive particles 17 (see FIG. 2). As a supply means for supplying the conductive particle dispersion solution 7 onto the dielectric thin film 4, a layer of the conductive particle dispersion solution 7 is formed on the surface of the rotary roll as shown in FIG. There is a configuration to contact. In addition, a method of spraying the conductive particle dispersion solution 7 with a nozzle, or a method of dipping the dielectric thin film 4 in which the electrostatic latent image 5 is formed in a solution in which the conductive particle dispersion solution 7 is collected may be mentioned. have.

Next, the operation of the apparatus of FIG. 1 will be described.

First, when the device is activated, erasing means (eraser) 10 for erasing the electrostatic latent image 5 on the dielectric thin film 4 formed on the photosensitive drum surface is operated, and then the cleaning device (cleaner) 11 is operated. By this, the conductive particles 17 remaining on the surface are removed. Thereafter, the erasing means 10 is stopped, and the cleaning device 11 is separated from the drum surface. Next, the surface of the dielectric thin film 4 is equally charged by the charging device 1. Next, based on an image signal sent from an image processing apparatus such as a personal computer (not shown), the electrostatic latent image 5 is formed by irradiating light onto the dielectric thin film 4 in which the exposure apparatus 3 is similarly charged. Next, the developing roll provided in the developing apparatus 6 is contact-rotated to the photosensitive drum, and the conductive particle 17 in the electroconductive particle dispersion liquid 7 adheres to the electrostatic latent image 5, and is visualized. The visualized image is transferred to the substrate 8 by the transfer device 9.

The board | substrate 8 which received the image formed from the electroconductive particle 17 is conveyed to the heating apparatus 15 side, it heats there, and electroconductive particle melts, and is fixed to the board | substrate 8 (14). The ionic organic molecules attached to the outside of the conductive particles are vaporized and removed by the heating.

The detail of the electroconductive particle dispersion solution 7 of this invention is shown in FIG. The electroconductive particle dispersion solution 7 of this invention is made by disperse | distributing the electroconductive particle 17 of 100 nm or less in particle diameter which the ionic organic molecule 16 adsorbed on the surface in the nonpolar solvent 15. As shown in FIG. This ionic organic molecule 16 is provided in order to provide charge to the conductive particles and to prevent aggregation between the particles.

In the case of the polymer, the ionic organic molecule 16 of the present invention is a styrene such as polystyrene, poly-p-chlor styrene, polyvinyl toluene, styrene-p-chlor styrene copolymer, styrene-vinyl toluene copolymer and its substituents Homopolymers and copolymers thereof, copolymers of styrene and acrylic esters such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid-n-butyl copolymer, styrene-methyl methacrylate Copolymers of styrene and methacrylic acid esters such as copolymers, styrene-ethyl methacrylate copolymers, styrene-methacrylic acid-n-butyl copolymers, plural copolymers of styrene, acrylic esters and methacrylic acid esters, Other styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-butadiene copolymers, styrene-vinylmethyl ketone copolymers, Styrene copolymer of styrene and other vinyl monomers, such as a styrene-maleic acid ester copolymer, methacrylic acid ester resins, such as polymethyl methacrylate and polybutyl methacrylate, methyl polyacrylate, ethyl polyacrylate, polyacrylic acid The polymer resins, such as butyl ester resin, polyester resin, epoxy, cycloolefin copolymer, etc. which are single or mixed with functional groups which can give ionicity, such as a carboxylic acid group and an amino acid group, are mentioned.

In the case of low molecular weight organic molecules, oxalic acid, malonic acid, succinic acid, adipic acid, glutaric acid, 2,4-diethylglutaric acid, 2,4-diethylglutaric acid, pimeline acid, azeline acid, Dicarboxylic acids such as sebacic acid, cyclohexane dicarboxylic acid, maleic acid, fumaric acid, and diglycolic acid, caprylic acid, lauryl acid, myristic acid, palmitic acid, stearic acid, arachinic acid, behenic acid, linoleic acid, oleic acid, Aliphatic carboxylic acid ions (19) by fatty acids, such as linolenic acid, hydroxycarboxylic acids, such as lactic acid, hydroxy pivalic acid, dimethyl all propionic acid, citric acid, malic acid, and glycerin acid, Ag, Cu And aliphatic carboxylic acid inorganic salts composed of inorganic ions 18 such as Au, Pd, Pt, Ni, W, Mo, and Cr. At this time, in order to lower the organic molecular component in the conductive pattern for lowering the resistance, and to carry out low temperature firing in order to realize conductive pattern formation on a resin substrate such as polyimide, the latter low molecular weight organic molecules as shown in FIG. Is preferably.

The particle diameter of the conductive particles 17 of the present invention needs to be 100 nm or less in order to realize low temperature fusion or high resolution, but more preferably 10 nm or less in order to fuse by heating of 200 degrees or less. In addition, in order to realize conductive pattern formation having a line width of 100 nm or less, the thickness is preferably 5 nm or less. The component of the conductive particles 17 may be a single metal such as Ag, Cu, Au, Pd, Pt, Ni, W, Mo, Cr, an oxide thereof, or an alloy thereof, but for use as a conductor It is preferable to use Ag and Cu with low volume resistivity. In addition, the conductive particles may be a mixture of a plurality of them.

It is preferable that the nonpolar solvent 15 of this invention is an aliphatic hydrocarbon solvent, and isoparaffinic system, petroleum naphtha system, isopa (Exxon company), IP solvent (Sutsko petroleum company), soltor (Philips petroleum company), its And other hydrocarbons.

Hereinafter, although the specific example was given about preparation of the inorganic fine particle dispersion medium of this invention, it is not specifically limited to this method.

In 100 ml of special methanol (made by Wako Chemical), 3.5 g of stearic acid (manufactured by Wako Chemical) was added thereto, heated to reflux, and completely dissolved. 1.5 g of silver nitrate (manufactured by Wako Chemical Co., Ltd.) was dissolved in 25 ml of pure water, and a silver nitrate aqueous solution dissolved therein was added dropwise over 10 minutes. This gave a white precipitate in the solution. After completion of the dropwise addition, the mixture was further heated and stirred for 30 minutes, and then the apparatus was cooled to room temperature, and the white precipitate was filtered and dried to obtain 5.0 g of white silver stearic acid. Next, 1.0 g of stearic acid obtained was put into a furnace, and heated at 250 degrees under nitrogen for 4 hours to obtain a purple individual. After washing the solid with alcohol, 100 mg was added to 10 ml of isopa H (manufactured by Exxon), sonicated for 5 minutes, and heated at 60 ° C for 30 minutes. Brown silver particles which did not show sedimentation even after standing. A dispersion was obtained. At this time, the particle diameter was confirmed to be 10 nm. Further, a stainless steel electrode plate was immersed in this silver particle dispersion liquid, and when direct current charge of 10 V was applied for 1 min at a distance of 1 mm between electrodes, electrodeposition of particles on the anode side was confirmed. Therefore, it was found that the silver particles in the dispersion medium were negatively charged.

The transfer means 9 which transfers the conductive particle pattern 12 developed on the dielectric thin film 4 by the developing apparatus 6 which forms the conductive pattern in this invention on the board | substrate 8 is provided. The conductive particle pattern formed on the dielectric thin film may be transferred onto the substrate 8 after being transferred onto the intermediate transfer member. At this time, the substrate 8 to which the conductive pattern is transferred needs to have insulation.

In the conductive pattern forming apparatus of the present invention, the conductive particle pattern 12 transferred onto the substrate 8 is fixed on the substrate 8 and provided with heating means 13 for forming the conductive pattern 14. At this time, the heating means 13 did not come out enough to fuse the conductive particles 17, but vaporized by firing the ionic organic molecules 16 on the surface of the conductive particles, so that only molten conductive particles remained. Moreover, it may have a function which can press the electrically conductive particle pattern 12 on the board | substrate 8 simultaneously with heating. At this time, the heating temperature is preferably 300 ° C. or lower in order to sufficiently fuse the conductive particles to bake and vaporize the ionic organic molecules and to prevent deformation and modification of the substrate 8. At this time, an exhausting means for exhausting the vaporized organic matter component may be provided.

Hereinafter, although another Example is given about the conductive pattern formation by the heating of this invention, it is not specifically limited to this method.

In this embodiment, a 0.5 mm × 8 mm conductive particle pattern formed on a polyimide was heated at 250 ° C. for 1 hour with a hot plate to obtain a conductive pattern of 0.5 mm × 8 mm silver having a metallic gloss on the surface.

In the conductive pattern forming apparatus in this embodiment, drying means for drying and evaporating the solvent component of the conductive pattern after being developed may be provided. The evaporated solvent may be liquefied and returned to the developing apparatus 6, and may be recycled again as the nonpolar solvent 15 for diluting the concentration of the conductive particle dispersion solution 7.

In the conductive pattern forming apparatus of the present invention, the dielectric thin film 4 may have a configuration in which a latent image is formed again after transferring the conductive pattern to develop the conductive particle pattern 12. As a shape, it is preferable that it is a belt shape or a drum shape. At this time, it is preferable to have a means (eraser) 10 for erasing the residual electrostatic latent image of the dielectric thin film body after transfer and a cleaning means 11 for removing and recovering the remaining conductive particles 17. Examples of the cleaning means 11 include a method in which a blade is brought into contact with the dielectric thin film 4 and scraped off, or a method of washing with a solvent. In addition, the removed and recovered conductive particles 17 may be returned to the developing means 7 and dispersed again in the conductive particle dispersion solution 7 for recycling.

(Example 2)

Next, another embodiment of the present invention will be described with reference to FIG. In the previous embodiment, the drum-like dielectric surface was equally charged and irradiated with light to form a latent electrostatic image. However, in the present embodiment, a mask having a pattern formed in advance is used.

In the latent electrostatic image forming means of the present invention, as shown in FIG. 4, the mask 20 having an arbitrary pattern is brought into close contact with the surface of the dielectric thin film 4. Next, the charging means 1 charges the upper portion of the mask 20. As a result, the surface of the dielectric thin film 4 is charged through the opening in which the pattern is formed. The electrostatic latent image pattern 5 is formed on the surface of the dielectric thin film 4 by removing the mask 20 after that. At this time, it is preferable that the surface opposite to the charged side of the dielectric thin film 4 has the conductive thin film layer 21, and the conductive thin film layer 21 is in a ground state.

Although the specific example was mentioned about the phenomenon of the latent electrostatic image of a present Example, it is not specifically limited to this method.

In this invention, the board | substrate with which the polyimide film (45 micrometers) was formed on 8-micrometer-thick copper foil on one side was prepared. A metal mask having a pattern of 0.5 mm x 8 mm was brought into close contact with the polyimide film of the substrate, and the electrostatic latent image pattern having a surface potential of about 1000 V was obtained by charging with a corona charger thereon. The polyimide substrate which has the obtained electrostatic latent image was immersed in electroconductive particle dispersion solution for 1 second, and it dried naturally for 10 minutes, and the silver particle assembly film of the pattern of 0.5 mm x 8 mm was obtained. In addition, during the above operation, the copper foil side on the opposite side of the polyimide film was in a ground state.

The conductive pattern formed in the conductive pattern forming apparatus of the present invention may be, for example, a personal computer, a large electronic calculator, a notebook personal computer, a pen input personal computer, a notebook word processor, a mobile phone, a mobile card, a wrist watch, a camera, Electric shaver, cordless phone, fax, video, video camera, electronic organizer, electronic calculator, electronic notebook with communication function, portable copy machine, liquid crystal television, power tools, vacuum cleaner, game machine having functions of vigilant reality, toys, electric bicycle Can be used as board wiring for medical care walking aids, medical care wheelchairs, portable medical care beds, escalators, elevators, forklifts, golf carts, emergency power supplies, load conditioners, and power storage systems. In addition to civilian use, it can also be used for military use and space use.

Claims (6)

A conductive pattern forming apparatus comprising: electrostatic latent image forming means for forming an electrostatic latent image on the surface of a dielectric thin film; A conductive pattern forming apparatus, wherein the conductive particle dispersion solution disperses conductive particles having a particle diameter of 100 nm or less in a nonpolar solvent in which ionic organic molecules are adsorbed on a surface thereof. The method of claim 1, And transfer means for transferring the conductive pattern formed on the surface of the dielectric thin film onto the conductive pattern forming substrate. The method of claim 1, And transfer means for transferring the conductive pattern onto the intermediate transfer member, and transfer means for transferring the conductive pattern transferred onto the intermediate transfer member onto the conductive pattern forming substrate. The method of claim 2 or 3, And a means for heating or pressurizing the conductive pattern transferred onto the substrate. The method of claim 1, The electrostatic latent image forming means includes a dielectric thin film body formed of a photosensitive material which loses surface charge of the irradiation part by light irradiation of a constituent material, electrostatic charge applying means for forming a static charge on the surface of the dielectric thin film body, and the dielectric thin film. And electrostatic charge applying means for forming an electrostatic charge on the surface of the body, and exposure means for forming an electrostatic latent image pattern by irradiating light to the electrostatic charge on the surface of the dielectric thin film body. The method of claim 1, Wherein the dielectric thin film body is photosensitive, and comprises a charging means for equally charging the surface of the dielectric thin film and an exposure means for irradiating light to an arbitrary portion of the surface of the dielectric thin film that is equally charged. .

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