JP4895397B2 - Wiring board manufacturing method and wiring board manufacturing apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing a wiring board and an apparatus for manufacturing a wiring board.

  A wiring pattern of a wiring board used for an electronic circuit, an integrated circuit, or the like is generally formed by photolithography. In recent years, a technique for forming this wiring pattern by ink jet has been proposed (for example, Patent Document 1). 2).

In the method for manufacturing a wiring board disclosed in Patent Documents 1 and 2, a solution in which conductive fine particles are dispersed is ejected by an ink jet to form a desired wiring pattern on the board. The substrate is formed with a receiving layer that absorbs the solvent in the ejected droplets. The receiving layer absorbs the solvent and is subjected to heat treatment to form a conductive film (wiring pattern) formed of conductive fine particles. ) On the receiving layer.
JP 2006-059983 A JP 2004-345321 A

  In general, a dispersant is added to a solution ejected by inkjet in order to disperse conductive fine particles. If this dispersant remains in the wiring pattern, the aggregation of the conductive fine particles is hindered, so that the resistivity of the wiring pattern increases.

  In the method for manufacturing a wiring board disclosed in the above cited references 1 and 2, heat treatment is performed to remove the dispersant in the gas phase, and the conductive fine particles are aggregated with each other. However, for example, when a plastic substrate is used, the heat treatment temperature is typically 150 ° C. or lower. Thus, depending on the material forming the substrate and the receiving layer, the heat treatment cannot be sufficiently performed, and the heat treatment is not dispersed. In some cases, the agent could not be removed sufficiently.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a wiring board manufacturing method and manufacturing apparatus in which the resistivity of a wiring pattern is reduced.

The above object of the present invention is achieved by the following method for manufacturing a wiring board.
(1) A wiring pattern forming step of forming a desired wiring pattern by ejecting droplets of a solution in which conductive fine particles are dispersed using a dispersant on a receiving layer provided on a substrate, and at least the wiring pattern A method for manufacturing a wiring board, further comprising: a solvent supplying step for further supplying a solvent of the solution.
(2) The method for manufacturing a wiring board according to (1), wherein, in the solvent supply step, the solvent is supplied before the wiring pattern is solidified.
(3) In the solvent supply step, the solvent is ejected and supplied, and the solvent is ejected to a position on the rear side of the droplet ejecting unit along the scanning direction of the droplet ejecting unit that ejects the droplet. The method for manufacturing a wiring board according to (2), wherein a solvent injection unit is provided, and the wiring pattern forming step and the solvent supplying step are performed in parallel.
(4) The method for manufacturing a wiring board according to any one of (1) to (3), wherein, in the solvent supplying step, the solvent is supplied within a solvent receiving amount of the receiving layer.

According to the method for manufacturing a wiring board having the configuration (1), a part of the dispersant contained in the droplet ejected on the receptor layer is absorbed by the receptor layer together with the solvent. Therefore, after the wiring pattern is formed on the receiving layer, a solvent is further supplied onto the wiring pattern, so that the dispersing agent remaining in the wiring pattern can be further absorbed into the receiving layer and the resistivity of the wiring pattern can be reduced. it can. Here, the volume of the ejected droplet is limited by droplet ejecting means such as an inkjet head or a dispenser nozzle. In terms of promoting absorption of the dispersant into the receiving layer, it is conceivable to increase the content of the solvent in the droplets. However, in this case, the content of the conductive fine particles in the droplet is reduced, and there is a concern that the wiring pattern is made thinner and the actual resistance as the wiring is thereby increased. On the other hand, according to the method for manufacturing a wiring board of this configuration, the solvent is supplied separately from the droplets forming the wiring pattern, and the content of the conductive fine particles in the droplets is sacrificed. Therefore, an appropriate amount of solvent can be supplied, and the resistivity of the wiring pattern can be reliably reduced.
According to the method for manufacturing a wiring board having the configuration of (2) above, by supplying a solvent before the wiring pattern is solidified, the solvent can be penetrated into the wiring pattern, and to the receiving layer of the dispersant. Can be further promoted. Thereby, the resistivity of the wiring pattern can be reduced.
According to the method of manufacturing the wiring board having the configuration (3), the solvent can be supplied before the wiring pattern is solidified. Further, the manufacturing process can be reduced by shortening the process.
According to the manufacturing method of the wiring board having the configuration (4), it is possible to prevent the wiring pattern from collapsing such as edge bleeding and to maintain the effect of reducing the resistivity of the wiring pattern. Further, the supply amount of the solvent can be saved and the manufacturing cost can be reduced.

The above-mentioned object of the present invention is achieved by the following wiring board manufacturing apparatus.
(5) Droplet ejection means for ejecting droplets of a solution in which conductive fine particles are dispersed using a dispersant onto a receiving layer provided on a substrate to form a desired wiring pattern, and at least the wiring pattern A wiring board manufacturing apparatus, further comprising: a solvent supply unit that further supplies the solvent of the solution.
(6) The solvent supply unit is configured to eject the solvent, and is provided at a position on the rear side of the droplet ejecting unit along the scanning direction of the droplet ejecting unit. The wiring board manufacturing apparatus according to (5).

According to the wiring board manufacturing apparatus having the configuration (5), a part of the dispersant contained in the ejected droplets is absorbed by the receiving layer together with the solvent. Therefore, the solvent can be further supplied onto the wiring pattern formed on the receiving layer, and the dispersing agent remaining in the wiring pattern can be further absorbed into the receiving layer, thereby reducing the resistivity of the wiring pattern.
According to the wiring board manufacturing apparatus having the configuration (6), the formation of the wiring pattern on the receiving layer and the supply of the solvent onto the wiring pattern can be performed in parallel. Thereby, before the wiring pattern is solidified, the solvent can be supplied to the wiring pattern, and the absorption of the dispersant into the receiving layer can be further promoted. In addition, the manufacturing process can be reduced by shortening the process.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and manufacturing apparatus of a wiring board which made the resistivity of a wiring pattern small can be provided.

  A preferred embodiment of a wiring board manufacturing method and manufacturing apparatus according to the present invention and a wiring board manufactured thereby will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a view for explaining a first embodiment of a method for manufacturing a wiring board according to the present invention.
In the method for manufacturing a wiring board according to the present embodiment, a desired wiring pattern is formed by injecting droplets of a solution L in which conductive fine particles are dispersed using a dispersant onto a receiving layer 2 provided on the board 1. A wiring pattern forming step, and a solvent supplying step of further supplying a solvent of the solution on at least the wiring pattern.

  As a material of the substrate 1, an appropriate material is selected according to the application. For example, glass or the like can be used for a wiring board of a flat panel display such as a liquid crystal display, a plasma display, or an organic EL display. An organic film such as polyimide can be used for a flexible printed wiring board, and a base paper or ceramic impregnated with a phenol resin or an epoxy resin can be used for a rigid one.

  The receiving layer 2 quickly absorbs the solvent of the solution L and fixes the conductive fine particles. For example, the receiving layer 2 has a large number of microvoids (so-called void-type receiving layer), or mainly a water-soluble resin or a parent layer. It can be set as the receiving layer (what is called swelling type receiving layer) which consists of oil-based resin.

  The void-type receiving layer can be formed, for example, by applying a mixture of silica particles, alumina particles, boehmite particles, or a combination thereof and a binder to the surface of the substrate 1. As the binder, polyvinyl alcohol can be suitably used. After the mixture is applied to the surface of the substrate 1, a porous layer to be the receiving layer 2 is formed by performing a drying process to evaporate the solvent and solidify the binder. The mixture may be applied to the entire substrate 1. However, it is preferable to apply only the predetermined portion where the wiring pattern is formed later, because the material can be saved.

  As the solution L injected onto the receiving layer 2, for example, a solution in which metal fine particles such as gold, silver and copper, semiconductor fine particles of ZnO, Si and ZnS are dispersed in a solvent can be used.

  The solvent of the solution L is not particularly limited as long as the conductive fine particles can be dispersed and does not cause aggregation. For example, tetradecane or the like can be used as the nonpolar solvent, and water or the like can be used as the polar solvent.

  In order to improve the dispersibility of the conductive fine particles, a dispersant is added to the solution L. As the dispersant, for example, dodecylamine can be used. By adding the dispersant, the aggregation of the conductive fine particles is prevented, and the fluidity of the solution L is kept good.

(Wiring pattern formation process)
As shown in FIG. 1A, droplets of the solution L are ejected onto the receiving layer 2 provided on the substrate 1. In the wiring board manufacturing apparatus for carrying out the manufacturing method of the present embodiment, as the droplet ejecting means 10 for ejecting the droplets of the solution L, for example, an inkjet head, a nozzle of a dispenser, or the like can be used. The droplet ejecting means 10 is moved relative to the substrate 1 and ejects droplets of the solution L to a desired position on the receiving layer 2.

  As shown in FIG. 1B, the droplets of the solution L that have landed on the receiving layer 2 quickly absorb the solvent contained in the receiving layer 2. As a result, the conductive fine particles contained in the droplets are fixed on the receiving layer 2. A part of the dispersant contained in the droplet is also absorbed by the receiving layer 2 together with the solvent. As a result, the conductive fine particles contained in the droplets aggregate due to a dramatic drop in the melting point due to the nano-scaling and develop conductivity. In this way, a desired wiring pattern 3 is formed on the receiving layer 2.

(Solvent supply process)
Next, in the method for manufacturing a wiring board according to the present embodiment, the solvent LS of the solution L is further supplied onto at least the wiring pattern 3 as shown in FIG. As the means for supplying the solvent LS, various means such as spray coating, spin coating, dipping, screen printing, gravure printing and the like can be used. In the figure, as the solvent supplying means 11, an inkjet head or dispenser is used. A configuration in which the solvent LS is ejected using a nozzle or the like is shown. The supply of the solvent LS may be supplied to the entire substrate 1 or the receiving layer 2. However, if the supply of the solvent LS is performed only on the wiring pattern 3 by an inkjet or a dispenser, the supply amount of the solvent LS can be saved. This is preferable.
In addition, the solvent LS is not only a pure solvent component, but also has a small amount of additives such as a viscosity adjusting agent and a surface tension adjusting agent (surfactant, etc.) in order to facilitate ejection by inkjet or the like. Good.

  The solvent LS supplied onto the wiring pattern 3 penetrates into the wiring pattern 3 and is absorbed by the receiving layer 2. At that time, the dispersing agent remaining in the wiring pattern 3 in the wiring pattern forming step is absorbed by the receiving layer 2 together with the solvent LS. Thereby, aggregation of the conductive fine particles forming the wiring pattern 3 is promoted, and the resistivity of the wiring pattern 3 is reduced.

  In this solvent supply step, it is preferable to supply the solvent LS before the wiring pattern 3 is solidified. Thereby, the solvent LS can be penetrated into the inside of the wiring pattern 3, and absorption of the dispersant into the receiving layer 2 can be further promoted.

  In addition, it is preferable to supply the solvent LS within the solvent acceptance amount of the receiving layer 2. Thereby, collapse of the wiring pattern 3 such as edge bleeding can be prevented, and the effect of reducing the resistivity of the wiring pattern 3 can be maintained. Moreover, the supply amount of the solvent LS can be saved, and the manufacturing cost can be reduced.

  After passing through the above-described solvent supply step, the wiring substrate is left, for example, at room temperature and atmospheric pressure, and the receiving layer 2 and the wiring pattern 3 are dried.

[Second Embodiment]
Next, a second embodiment of the method for manufacturing a wiring board according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the element which is common in the manufacturing method of 1st Embodiment mentioned above, and description is abbreviate | omitted or simplified.

  In the wiring board manufacturing apparatus that performs the wiring board manufacturing method of the present embodiment, the solvent supply unit 11 that supplies the solvent LS onto the wiring pattern 3 injects the solvent LS using an inkjet head, a nozzle of a dispenser, or the like. It is supposed to be configured. The solvent supply unit 11 is provided at a position on the rear side of the droplet ejection unit 10 along the scanning direction of the droplet ejection unit 10, and is integrated with the droplet ejection unit 10 with respect to the substrate 1. It is moved relative.

  The manufacturing method of the wiring board of the present embodiment uses the manufacturing apparatus having the above-described configuration, and performs the above-described wiring pattern forming process and the solvent supplying process in parallel. That is, as shown in FIG. 2, the droplet ejecting means 10 is relatively moved while ejecting the droplet of the solution L, and the wiring pattern 3 is formed on the receiving layer 2. The solvent supply means 11 that is relatively moved together with the droplet ejecting means 10 is positioned above the wiring pattern 3 formed on the receiving layer 2 and ejects the solvent LS there.

  Thus, the solvent LS is supplied to the wiring pattern 3 before the wiring pattern 3 is solidified. The solvent LS supplied to the wiring pattern 3 is absorbed by the receiving layer 2 together with the dispersant remaining in the wiring pattern 3 as described above. Thereby, aggregation of the conductive fine particles forming the wiring pattern 3 is promoted, and the resistivity of the wiring pattern 3 is further reduced.

  Then, by performing both the wiring pattern forming step and the solvent supplying step in parallel, the time required for both steps can be shortened and the manufacturing cost can be reduced.

  Hereinafter, examples and comparative examples will be described.

  The wiring board of Example 1 was formed by injecting a solution containing silver fine particles with an ink jet to form a wiring pattern, and then applying a solvent once onto the entire surface of the board with an ink jet and drying at room temperature.

  The wiring board of Example 2 was formed by injecting a solution containing silver fine particles with an ink jet to form a wiring pattern, and then applying a solvent twice on the entire surface of the board with an ink jet and drying at room temperature.

  The wiring board of Example 3 was formed by injecting a solution containing silver fine particles with an ink jet to form a wiring pattern, and then applying a solvent three times over the entire surface of the board with an ink jet and drying at room temperature.

  The wiring substrate of Comparative Example 1 was formed by injecting a solution containing silver fine particles with an ink jet to form a wiring pattern, and was dried at room temperature.

The resistances of the wiring patterns of Examples 1 and 2 and Comparative Example 1 were measured to determine their resistivity. The resistivity of Example 1 is 7.0 × 10 ⁻⁶ [Ωm], the resistivity of Example 2 is 3.9 × 10 ⁻⁵ [Ωm], and the resistivity of Comparative Example 1 is 9.0. × 10 ⁻⁶ [Ωm]. In the wiring board of Example 3, a phenomenon was observed in which extreme bleeding occurred at the edge of the wiring pattern and the wiring pattern collapsed.

  It can be seen from Example 1 and Comparative Example 1 that the resistivity of the wiring pattern can be reduced by supplying a solvent to the wiring pattern.

  Further, from Example 1, Example 2 and Example 3, Example 2 and Example 3 are supplied with a solvent exceeding the amount of solvent accepted by the receiving layer, and the effect of reducing the resistivity of the wiring pattern by the supply of the solvent Is considered to have been inhibited.

  As described above, according to the method and apparatus for manufacturing a wiring board and the wiring board according to the present invention, the resistivity of the wiring pattern is reduced.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the shape, size, numerical value, form, number, location, and the like of each element in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the method for manufacturing a wiring board according to the above-described embodiment, the wiring board may be positively heated after the solvent supply step and may be dried under reduced pressure.

  In addition, the number of times of supply of the solvent in the solvent supply step is not limited to one time and may be supplied a plurality of times as long as it is within the solvent acceptance amount of the receiving layer 2. For example, in the wiring board manufacturing apparatus of the second embodiment described above, a plurality of solvent supply means 11 are used, and these solvent supply means 11 are aligned on the rear side of the droplet ejection means 10 along the scanning direction. It may be provided.

The figure explaining 1st Embodiment of the manufacturing method of the wiring board which concerns on this invention. The figure explaining 2nd Embodiment of the manufacturing method of the wiring board which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Receiving layer 3 Wiring pattern 10 Droplet ejecting means 11 Solvent supply means L Solution LS Solvent

Claims (6)

A wiring pattern forming step of forming a desired wiring pattern by ejecting droplets of a solution in which conductive fine particles are dispersed using a dispersant on a receiving layer provided on a substrate;
A solvent supply step of further supplying a solvent of the solution on at least the wiring pattern;
A method of manufacturing a wiring board, comprising:   The method for manufacturing a wiring board according to claim 1, wherein, in the solvent supplying step, the solvent is supplied before the wiring pattern is solidified. In the solvent supply step, the solvent is injected and supplied,
A solvent ejecting means for ejecting the solvent is provided at a position on the rear side of the droplet ejecting means along the scanning direction of the droplet ejecting means for ejecting the droplets,
The method for manufacturing a wiring board according to claim 2, wherein the wiring pattern forming step and the solvent supplying step are performed in parallel.   The method for manufacturing a wiring board according to claim 1, wherein, in the solvent supplying step, the solvent is supplied within a solvent receiving amount of the receiving layer. Droplet ejection means for ejecting droplets of a solution in which conductive fine particles are dispersed using a dispersant onto a receiving layer provided on a substrate to form a desired wiring pattern;
Solvent supply means for further supplying a solvent of the solution on at least the wiring pattern;
An apparatus for manufacturing a wiring board, comprising:   The solvent supply unit is configured to eject the solvent, and is provided at a position on the rear side of the droplet ejection unit along the scanning direction of the droplet ejection unit. The manufacturing apparatus of the wiring board of 5.

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