JP2009061408A - Wiring pattern forming method and wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring (circuit) pattern forming method employing a droplet discharge method or electroless plating, by which a wiring pattern having high reliability can be formed by preventing the unsteady landing shape of an ink droplet or plating deposition on a undesirable part, and to provide a wiring board manufactured using the method. <P>SOLUTION: The wiring pattern forming method includes a step for forming an ink pattern using ink containing a catalyst for electroless plating by the droplet discharge method and a step for depositing a plating metal on the ink pattern by the electroless plating. The droplet discharge method is used for discharging the droplets from a droplet discharge head comprising a pressure chamber in communication with a discharge hole 11, a pressure generating element causing a change in pressure of a liquid in the pressure chamber and a driving voltage applying means. The voltage Ve applied to the driving voltage applying means in the discharge of the droplets satisfies expression; V1<Ve<V2 (in the expression, V1 expresses the maximum voltage at which the liquid from the ejection port is swelled but does not form the droplet and V2 expresses the minimum voltage at which the droplet discharged from the discharge port is divided into a plurality of parts during the flying). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of forming a wiring pattern using a droplet discharge method and electroless plating, and a wiring substrate having a wiring pattern formed thereby.

  In recent years, as a method of forming a fine conductive circuit pattern on an insulating substrate such as a printed wiring board or forming an electrode of a TFT (thin film transistor) used in an FPD or the like, a conductive material in which conductive fine particles such as metal are dispersed is used. There has been proposed a method for obtaining a desired pattern by using an ink jet method (referred to as a “droplet discharge method” in the present application) of a functional solution. By using the inkjet method, the conventional photolithography method requires the use of many steps (repetition of conductive film formation, resist coating, exposure, development, etching, etc.) and materials (photoresist, developer, cleaning solution, etc.). On the other hand, since the process is simple and the amount of materials and energy used is small, it is attracting attention as a method capable of forming a fine wiring pattern at low cost (for example, Patent Document 1). reference).

  In addition, a method of performing electroless plating on a wiring pattern formed by an inkjet method is also known, and plating is performed even when the wiring pattern obtained by the inkjet method does not satisfy a desired film thickness or conductivity. Thus, the thickness of the wiring pattern can be increased to obtain a desired film thickness and conductivity (see, for example, Patent Document 2).

  On the other hand, various types of ink jet methods such as a piezo method and a thermal method are known. Depending on conditions such as increasing the initial velocity at the time of ejection, particularly when ejecting minute droplets, droplets may be ejected at the time of ejection. May be stretched and the rear end may split. The divided fine droplets are called so-called “satellite”, and they adhere to the position that is later than the main droplet and is out of the desired landing position or drift in the space without adhering. When used for image formation, it is not preferable because it leads to deterioration of image quality and the like, and development to prevent generation of satellites has been carried out (see, for example, Patent Document 3).

When forming a wiring pattern using an inkjet method, a method of depositing a plating metal by performing an electroless plating process on a substrate on which a pattern is formed, using an ink that exhibits a function as a plating catalyst as an ink for forming the pattern However, when a satellite is generated when ink having catalytic ability is ejected by the ink jet method and adheres to a position different from a desired position, the shape of the pattern is disturbed or a metal other than the desired pattern is formed. In some cases, the plating metal may be deposited on a portion where the deposition is unnecessary. Disturbance of the pattern shape has an adverse effect on electrical characteristics when used as wiring, and metal deposition on undesired parts can cause a short circuit, so it cannot be used as a circuit board or electrode board. The yield decreases, resulting in a cost increase. This is particularly remarkable when a fine conductive pattern is formed at a high density. Also, even if the substrate is cleaned to remove the deposited metal on the unintended part, the necessary metal pattern may be removed depending on the cleaning conditions, so only the unnecessary deposited metal is removed. It is very difficult.
JP 2005-317744 A JP 2006-128228 A JP 2004-216877 A

  The present invention has been made in view of the above-described problems and situations, and the problem to be solved is that the ink landing shape is disturbed or unintentional in pattern formation such as wiring using a droplet discharge method and electroless plating. It is an object of the present invention to provide a formation method capable of forming a highly reliable wiring (circuit) pattern by preventing plating deposition on the substrate. Furthermore, it is providing the wiring board produced using the said formation method.

  The above-mentioned problem according to the present invention is solved by the following means.

1. A method for forming a wiring pattern by a droplet discharge method, wherein an ink pattern is formed by disposing an ink containing a composition exhibiting a function as a catalyst for electroless plating on a substrate by a droplet discharge method And a step of depositing a plating metal on the ink pattern by performing an electroless plating process on the substrate on which the ink pattern is formed, and the droplet discharge method includes a nozzle plate having discharge holes, and a discharge hole. It is a method of discharging droplets from a droplet discharge head comprising a communicating pressure chamber, a pressure generating element that causes a pressure fluctuation in a liquid in the pressure chamber, and a driving voltage applying unit that applies a voltage to the pressure generating element. A wiring pattern forming method, wherein the voltage Ve applied to the drive voltage applying means when discharging the droplet satisfies the following relational expression.
Relational expression: V1 <Ve <V2
(V1 is the maximum voltage at which the liquid rises from the discharge hole but returns to the discharge hole without forming a droplet, and V2 is the minimum voltage at which the droplet discharged from the discharge hole splits into multiple parts during flight. .)
2. 2. The method for forming a wiring pattern according to 1 above, wherein the ink is an ink containing fine metal particles having electroless plating catalytic ability.

  3. 3. The method of forming a wiring pattern according to 1 or 2, wherein the droplet discharge method is a method of flying droplets using electrostatic force in addition to the action of the pressure fluctuation.

  4). 4. The method for forming a wiring pattern according to any one of 1 to 3, further comprising a step of providing a base layer on the substrate prior to forming the ink pattern on the substrate.

  5). 5. The method for forming a wiring pattern according to any one of 1 to 4, further comprising a step of disposing an insulating layer at a position where the ink pattern of the substrate is not formed.

  6). 6. The method for forming a wiring pattern according to 5, wherein the step of disposing the insulating layer is performed by a droplet discharge method.

  7. 7. The method for forming a wiring pattern according to 5 or 6, wherein the insulating layer contains a plating deposition inhibiting component as a constituent component thereof.

  8). The insulating layer is composed of a compound containing a Group 12 element, a compound containing a Group 13 element, a compound containing a Group 14 element, and a compound containing a Group 16 element as the plating deposition inhibiting component. 8. The method for forming a wiring pattern as described in 7 above, which comprises a compound selected from the group.

  9. A wiring board comprising a wiring pattern formed by the method for forming a wiring pattern according to any one of 1 to 8 above.

  By the above-mentioned means of the present invention, highly reliable wiring (circuit) by preventing disorder of ink landing shape and plating deposition on unintended portions in pattern formation such as wiring using a droplet discharge method and electroless plating A forming method capable of forming a pattern can be provided. Furthermore, a wiring board manufactured using the formation method can be provided.

  That is, when a satellite is generated at the time of ink discharge and the satellite adheres to a position out of a desired landing position, there is a concern that unintended plating metal deposition may occur using the catalyst as a catalyst nucleus. By adopting the method, these concerns can be solved and a highly reliable wiring board can be manufactured.

  According to the second aspect of the invention, when the ink contains fine metal particles having catalytic ability, a good plating deposition pattern can be formed. Further, it becomes possible to impart conductivity to the pattern.

  According to the invention of claim 3, by adopting a droplet discharge method using electric power, it is possible to easily perform droplet discharge without generating satellites. Furthermore, since it is possible to fly minute droplets with high accuracy, it is possible to easily form a fine pattern with high density.

  According to the invention according to claim 4, the reliability as a wiring board, such as improving the adhesion between the pattern and the substrate and setting the wettability (contact angle) of the ink to a desired value by providing a base layer in advance. Can be improved.

  According to the invention of claim 5, since the insulating layer is disposed at a position other than the ink pattern, it is possible to suppress an increase in line width during plating growth, and to form a fine wiring pattern more reliably. Can do.

  According to the invention of claim 6, the insulating layer composition can be disposed on the substrate by the droplet discharge method, so that the insulating layer composition can be disposed with high accuracy without being erroneously disposed on the conductive ink. .

  According to the seventh aspect of the invention, unintended metal deposition can be prevented. That is, when the substrate is immersed in the plating bath to perform the electroless plating treatment, the conductive ink elutes in the plating solution, and when the catalyst component adheres to a position other than the conductive pattern on the substrate, the catalyst is removed. Electroless plating proceeds as a core, and unintended metal precipitation may occur. However, such an unintentional metal as described above due to the inclusion of a plating precipitation inhibiting component in the insulating layer as in the present invention. Precipitation can be prevented.

  By including the specific compound used in the invention according to claim 8, unintended plating deposition can be effectively prevented.

  Therefore, in the invention according to claim 9, by adopting the method according to any one of claims 1 to 8, a wiring line pattern can be produced in a simple process and highly reliable wiring. A (circuit) substrate can be produced.

The wiring pattern forming method of the present invention is a wiring pattern forming method by a droplet discharge method, and an ink containing a composition that exhibits a function as a catalyst for electroless plating is applied onto a substrate by a droplet discharge method. A step of forming an ink pattern by disposing, and a step of depositing a plating metal on the ink pattern by performing an electroless plating process on a substrate on which the ink pattern is formed, and the droplet discharge method includes: A droplet discharge head comprising a nozzle plate having discharge holes, a pressure chamber communicating with the discharge holes, a pressure generating element that causes a pressure fluctuation in the liquid in the pressure chamber, and a drive voltage applying unit that applies a voltage to the pressure generating element The voltage Ve applied to the drive voltage applying means when discharging the liquid droplets satisfies the following relational expression: That.
Relational expression: V1 <Ve <V2
(V1 is the maximum voltage at which the liquid rises from the discharge hole but returns to the discharge hole without forming a droplet, and V2 is the minimum voltage at which the droplet discharged from the discharge hole splits into multiple parts during flight. .)
The above features are technical features common to the inventions according to claims 1-9.

  In addition, as a preferable form (mode), the said ink is a form which is an ink containing the metal microparticles which have electroless-plating catalyst ability. Moreover, it is preferable that the droplet discharge method is a method of flying droplets using electrostatic force in addition to the effect of the pressure fluctuation.

  Furthermore, it is preferable that the method includes a step of providing a base layer on the substrate prior to forming the ink pattern on the substrate.

  Moreover, the form which has the process of arrange | positioning an insulating layer in the position in which the ink pattern of the said board | substrate is not formed is preferable. The step of disposing the insulating layer is preferably performed by a droplet discharge method. Further, the insulating layer contains a plating deposition inhibiting component as a constituent component thereof, a compound containing a Group 12 element of the periodic table, a compound containing a Group 13 element as the plating deposition inhibiting component, It is preferable to contain a compound selected from the group consisting of a compound containing a Group 14 element and a compound containing a Group 16 element.

  The wiring pattern forming method of the present invention can be suitably applied to the production of a highly reliable wiring board.

  Hereinafter, the present invention, its components, and the best mode for carrying out the invention will be described in detail.

(Droplet ejection method)
In the droplet discharge method used in the present invention, the liquid is discharged from the discharge hole provided in the nozzle plate by the action of the pressure generated in the liquid in the pressure chamber by driving the pressure generating means provided in the droplet discharge head. A known droplet discharge method can be used without particular limitation. In addition, a counter electrode facing the surface of the droplet discharge head provided with the discharge hole is provided, a potential difference is generated between the counter electrode and the liquid in the droplet discharge head, and the liquid is generated by the electrostatic force generated by the potential difference. A so-called electrostatic attraction type droplet discharge method for causing droplets to fly can also be used, and a method using both electrostatic force and the pressure in the head can also be preferably used.

(Droplet ejection head)
An example of a droplet discharge head preferably used in the present invention will be described with reference to FIGS.

  FIG. 1 schematically shows a nozzle plate 1, a body plate 2, and a pressure generating means 3 constituting an ink jet recording head (hereinafter referred to as a recording head) A which is an example of a droplet discharge head. . Here, a case where a piezoelectric element is used as the pressure generating means will be described.

  A plurality of ejection holes 11 for ejecting ink are arranged in the nozzle plate 1. Further, the nozzle plate 1 is bonded to the body plate 2 so that the pressure chamber groove 24 serving as a pressure chamber, the ink supply path groove 23 serving as an ink supply path, the common ink chamber groove 22 serving as a common ink chamber, and the ink. A supply port 21 is formed.

  And the flow path unit M is formed by bonding the nozzle plate 1 and the body plate 2 so that the discharge hole 11 of the nozzle plate 1 and the pressure chamber groove 24 of the body plate 2 correspond one-to-one. Hereafter, the reference numerals of the pressure chamber groove, the supply path groove and the common ink chamber groove used in the above description are also used for the pressure chamber, the supply path and the common ink chamber, respectively.

  Here, FIG. 2 shows a cross section of the recording head A after the nozzle plate 1, the body plate 2, and the piezoelectric element 3 are assembled, at positions YY of the nozzle plate 1 and XX of the body plate 2. Is schematically shown. As shown in FIG. 2, the piezoelectric element 3 is bonded to the flow path unit M to the surface of the bottom 25 of each pressure chamber 24 opposite to the surface to which the nozzle plate 1 of the body plate 2 is bonded. Thus, the recording head A is completed. A driving voltage is applied to each piezoelectric element 3 of the recording head A, and vibration generated from the piezoelectric element 3 is transmitted to the bottom 25 of the pressure chamber 24, and the pressure in the pressure chamber 24 is changed by the vibration of the bottom 25. Ink droplets are ejected from the ejection holes 11.

(Drive voltage)
The relationship between the driving voltage of the piezoelectric element and the behavior of the liquid in the ejection hole in the droplet ejection method of the present invention will be described.

  The droplet discharge head used in the present invention includes a nozzle plate having discharge holes, a pressure chamber communicating with the discharge holes, and a pressure generating element that causes a pressure fluctuation in the liquid in the pressure chamber, By applying a predetermined drive voltage to the element to cause a pressure fluctuation in the liquid in the pressure chamber, the liquid is discharged from the discharge hole. This liquid discharge state changes depending on the degree of pressure fluctuation, in other words, the drive voltage to the pressure generating element (the liquid discharge state is actually influenced not only by the drive voltage but also by various other factors. I will explain the influence of the drive voltage.)

  The behavior of the liquid in the ejection hole when the driving voltage is applied to the pressure generating element has the following three types of behavior as the value of the driving voltage increases from the smaller value (see FIG. 3).

  (1) A state in which the liquid rises from the ejection hole but is drawn into the ejection hole again without forming a droplet.

  (2) A state in which the liquid rises from the ejection hole and one droplet is formed.

  (3) A state in which the liquid rises violently from the discharge hole to form a liquid column and is separated from the discharge hole to form a droplet, but the liquid column itself is also divided to generate a plurality of droplets. The largest droplet among the divided droplets is called a main droplet, and the other minute droplets are called satellites.

  The threshold voltages of (1) and (2) and (2) and (3) differ depending on the shape of the head, the physical properties of the liquid, the applied voltage waveform, etc., but here the threshold voltages of (1) and (2) Is defined as V1, and the threshold voltage of (2) and (3) is defined as V2.

In the present invention, the drive voltage Ve applied to the pressure generating means when discharging the droplets from the droplet discharge head,
Relational expression: V1 <Ve <V2
By setting to a range that satisfies the above, it is possible to eject droplets in a discharge state in which no satellite is generated, and a favorable ink pattern can be formed.

  As an example of the waveform of the drive voltage Ve applied to the pressure generating means when ejecting the droplet, the waveforms shown in FIGS. 4 and 5 can be exemplified. However, it is not restricted to these waveforms.

(Droplet discharge method using electrostatic force)
An example of a droplet discharge apparatus used in a droplet discharge method using electrostatic force, which is preferably used in the present invention, will be described with reference to FIG.

  FIG. 6 schematically shows the overall configuration of a liquid discharge apparatus 60 configured using the droplet discharge head B. Electrostatic voltage application for charging the liquid in the nozzle made of a conductive material such as NiP, Pt, Au, etc., for example, on the inner peripheral surface of the large diameter portion 15 of the nozzle plate 1 used for the droplet discharge head B A charging electrode 50 as a means is provided. By providing the charging electrode 50, the charging electrode 50 comes into contact with the liquid in the large diameter portion 15 of the nozzle plate 1. When an electrostatic voltage is applied between the charging electrode 50 from the electrostatic voltage power supply 51 and the counter electrode 54 provided with the base material 53 on which the discharged droplets land, the liquid in the large diameter portion 15 is simultaneously discharged. Charged. Due to this charging, an electrostatic attraction force is generated between the counter electrode 54 provided at a position facing the nozzle hole 11 of the droplet discharge head, particularly between the liquid and the base material 53 on which the discharged droplets land. Can be generated.

  Piezoelectric elements 3 as pressure generating means are provided on the back surface portions corresponding to the pressure chambers 24, respectively. A driving voltage power source 52 for applying a driving voltage to the piezoelectric element 3 to deform the piezoelectric element 3 is connected to the piezoelectric element 3. The piezoelectric element 3 is deformed by the application of a driving voltage from the driving voltage power supply 52 to generate a pressure in the liquid in the nozzle and form a liquid meniscus in the discharge hole 13 of the nozzle 11. Here, as described above, the liquid repellent layer 45 is provided on the ejection surface 12 where the ejection holes 13 are present, so that the liquid meniscus formed in the ejection hole 13 portion of the nozzle is around the ejection holes 13. It is possible to effectively prevent a decrease in electric field concentration on the meniscus tip due to spreading on the discharge surface 12. A control unit 55 controls the liquid ejection device 60 such as the drive voltage power source 52 and the electrostatic voltage power source 51.

  Accordingly, a droplet discharge head capable of efficiently discharging droplets by a synergistic effect between the application of pressure to the liquid by the piezoelectric element 3 and the electrostatic attraction force to the liquid by the charging electrode 50 can be obtained. In other words, if electrostatic attraction force does not work, electrostatic attraction can be applied even when ejecting small droplets that do not reach the normal landing position due to the effect of air resistance during flight. It is possible to land at a regular landing position with high accuracy by the action of force, and it is possible to form a good ink pattern.

(ink)
The ink used in the present invention contains a composition having a function as a catalyst for electroless plating. In this case, the “function as a catalyst for electroless plating” refers to a function for depositing a plating metal at a position where the catalyst is applied when the electroless plating process is performed on the substrate provided with the catalyst.

  Although the form of the said composition is not specifically limited, As a preferable form, the form containing metal microparticles | fine-particles as a composition which has catalytic ability is mentioned.

  Examples of the metal fine particles used in the present invention include Au, Pt, Ag, Cu, Ni, Cr, Rh, Pd, Zn, Co, Mo, Ru, W, Os, Ir, Fe, Mn, Ge, Sn, Ga, In, and the like can be mentioned, among which Au, Ag, Pt, Pd, Rh, Ir, Cu or alloys containing these are preferably used because they have a high catalytic ability and can form a good plating pattern. It is done. These metal fine particles are preferably metal nanocolloids having an average particle diameter of 100 nm or less.

  In the fine metal particle-containing ink used in the present invention, a polymer or a surfactant can be used as a protective colloid of fine metal particles. Particularly, a block copolymer of polyester, polyacrylonitrile, polyurethane and alkanolamine is preferable. .

  Examples of the metal fine particle-containing ink used in the present invention include water-based ink and oil-based ink. A water-based conductive ink constituted by dispersing metal fine particles in a dispersion medium mainly containing water can be prepared, for example, according to the following method.

  A water-soluble polymer is dissolved in a metal ion source aqueous solution such as chloroauric acid or silver nitrate, and an alkanolamine such as dimethylaminoethanol is added with stirring. Metal ions are reduced in several tens of seconds to several minutes, and metal fine particles having an average particle diameter of 100 nm or less are deposited. Thereafter, chlorine ions and nitrate ions are removed by a filtration method such as ultrafiltration, and then concentrated and dried to obtain a water-based ink containing metal fine particles at a high concentration. This water-based ink can be stably dissolved and mixed in water, an alcohol-based solvent, a sol-gel process binder such as tetraethoxysilane or triethoxysilane.

  An oil-based ink in which metal fine particles are dispersed in an oil-based dispersion medium can be prepared, for example, according to the following method.

  The oil-soluble polymer is dissolved in a water-miscible organic solvent such as acetone, and the polymer solution is mixed with an aqueous metal ion source solution. Although the mixture is heterogeneous, when alkanolamine is added while stirring the mixture, metal fine particles are precipitated on the oil phase side in a form dispersed in the polymer. By washing, concentrating and drying this, an oil-based ink containing dense metal fine particles similar to the water-based ink can be obtained. This oil-based conductive ink can be stably dissolved and mixed in aromatic, ketone-based, ester-based solvents, polyesters, epoxy resins, acrylic resins, polyurethane resins, and the like.

  The concentration of the metal fine particles in the ink dispersion medium can be about 80% by mass at maximum, but can be appropriately diluted depending on the application. Usually, the content of metal fine particles in the ink is preferably 2 to 50% by mass, the content of the surfactant and the resin component is 0.3 to 30% by mass, and the viscosity is preferably 3 to 30 mPa · s.

  In addition to ink containing fine metal particles, a liquid composition containing the above metal as ions can be preferably used. In this case, after the ink is placed on the substrate, the metal ion in the ink placed on the substrate is reduced by performing a reduction treatment before performing the electroless plating treatment, so that the plating catalytic ability is expressed. By performing the electrolytic plating treatment, the plating metal is deposited, and a desired pattern can be obtained.

(substrate)
The substrate used in the present invention may be appropriately selected and used depending on the application. Examples thereof include polyimide films, polyamideimide films, polyamide films, polyester films, and other resin films, glass-epoxy substrates, silicon substrates. , Ceramic substrates, glass substrates and the like.

  The material of the resin film used in the present invention is not particularly limited. For example, polyester film (polyethylene terephthalate, polyethylene naphthalate, etc.), polycarbonate film, polyarylate film, polysulfone (including polyethersulfone). Film, polyethylene film, polypropylene film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, polycarbonate film, cycloolefin polymer film (Arton (manufactured by JSR), Zeonex, Zeonea (and above) , Manufactured by Nippon Zeon)), polyethersulfone film, polysulfone film, polymethylpentene film, poly Chromatography ether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, polyacrylate films, and polyarylate films. The film which laminated | stacked the film of the different material which has these materials as a main component may be sufficient.

(Underlayer)
In the present invention, a form in which a base layer is formed on the substrate prior to disposing the ink on the substrate is also preferably used. By disposing ink on a substrate provided with a base layer, the desired functions exemplified below can be expressed.

  (I) The adhesion between the substrate and the ink is improved, and the pattern formed by the ink can be prevented from peeling off from the substrate.

  (Ii) The ink arranged on the substrate can be prevented from being excessively wet and spread, and a fine pattern can be formed.

  Further, from the viewpoint that the present invention forms a wiring pattern, the underlayer preferably has an insulating property. Thereby, even when the wiring pattern is formed with a high wiring density, it is possible to prevent a short circuit from occurring between the patterns.

  The constituent material of the underlayer used in the present invention is not particularly limited, and various materials can be used according to the purpose. Examples of preferable constituent materials include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene. -Polyolefin such as vinyl acetate copolymer (EVA), cyclic polyolefin, modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamideimide, polycarbonate, poly- (4-methylpentene-1), ionomer , Acrylic resin, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer (AS resin), butadiene-styrene copolymer, polyoxymethylene, polyvinyl Polyesters such as coal (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexane terephthalate (PCT), polyether, polyether ketone (PEK), poly Ether ether ketone (PEEK), polyether imide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyfluoride Vinylidene fluoride, other fluororesins, styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide , Polybutadiene-based, trans-polyisoprene-based, fluororubber-based, chlorinated polyethylene-based thermoplastic elastomer, epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester, silicone resin, polyurethane, etc. Copolymers, blends, polymer alloys, and the like can be used, and one or more of these can be used in combination (for example, as a laminate of two or more layers).

  Moreover, when forming a base layer on a board | substrate, it is preferable to surface-treat a base material previously from a viewpoint of improving the adhesiveness of a base material and a contact | adherence layer. Examples of the surface treatment include plasma treatment, corona discharge treatment, flame treatment, ozone treatment, primer treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, and chemical treatment.

(Insulating layer)
The insulating layer used in the present invention is disposed on the substrate at a position where the ink pattern is not formed. When the plating process is applied to the ink pattern and the plated metal grows, the plated metal grows not only in the thickness direction but also in the direction of increasing the width, and even when the ink pattern is finely formed. The wiring pattern formed by the above may become thicker than the ink pattern and the fineness may be impaired. However, the arrangement of the insulating layer can suppress the increase in the line width and is preferably used.

  The insulating layer composition used as the insulating layer can use an insulating resin component or the like without particular limitation. Examples thereof include vinyl chloride resin, vinylidene chloride resin, fluororesin, silicon resin, acrylic resin, and epoxy resin. And an isocyanate curable urethane resin. These resin components can be used alone or in combination. In particular, a vinyl chloride resin, an acrylic resin, a mixture of an acrylic resin and a vinyl chloride resin, and the like are preferable because they are easy to handle and have good plating deposition prevention performance and film performance.

  Moreover, the form which arrange | positions an insulating layer composition on a base material by the droplet discharge method is also used preferably. In this case, various solvents and additives may be added in order to adjust the physical properties preferable for ejection by the droplet ejection method. Here, examples of various physical properties include surface tension, viscosity, and contact angle with respect to the substrate.

  Furthermore, a form in which a plating deposition inhibiting component is contained in the insulating layer composition is also preferably used.

  The precipitation inhibiting component is at least one selected from the group consisting of a compound containing a Group 12 element, a compound containing a Group 13 element, a compound containing a Group 14 element, and a compound containing a Group 16 element in the periodic table It is preferable that it is a compound of these.

  Specific examples of the precipitation inhibiting component include zinc compounds, cadmium compounds, mercury compounds, boron compounds, aluminum compounds, indium compounds, silicon compounds, germanium compounds, tin compounds, sulfur compounds, cerium compounds, tellurium compounds, and the like. These compounds can be selected as appropriate and used singly or in combination of two or more. In particular, the precipitation-inhibiting component is preferably a compound that is sparingly soluble or insoluble in water, and is a uniform fine particle having good dispersibility in the resin component, and the specific gravity is close to the specific gravity of the composition. It is preferable to use a compound that is difficult to separate and has high stability and does not decompose in the composition or film formation.

  Specific examples of the precipitation inhibiting component suitable for use in the present invention include zinc oxide, zinc chloride, ammonium zinc chloride, zinc peroxide, zinc silicofluoride, zinc nitrate, zinc carbonate and the like. Examples of the cadmium compound include cadmium oxide, cadmium chloride, cadmium nitrate, and cadmium sulfate. Examples of the mercury compound include mercuric chloride and mercuric oxide. Examples of the boron compound include Examples include boron trioxide, diboron trioxide, boron trichloride, potassium borofluoride, sodium borate, boric acid, zinc borate, ammonium borate, sodium borohydride, sodium perborate, and aluminum compounds include aluminum oxide. , Aluminum chloride, Aluminum nitrate, Aluminum nitrate, Aluminum Examples include white, aluminum silicate, aluminum sulfate, aluminum hydroxide, aluminum hydroxide oxide, sodium aluminate, magnesium metasilicate magnesium aluminate, and ammonium ammonium sulfate. Examples of indium compounds include indium trichloride. Examples of the silicon compound include silicon dioxide, sodium silicate, and silica gel. Examples of the germanium compound include germanium oxide and germanium tetrachloride. Examples of the tin compound include stannous chloride and chloride. Examples include stannic oxide, stannous oxide, stannic oxide, potassium stannate, sodium stannate, stannous pyrophosphate, hydrous stannic oxide, and stannous sulfate. As the sulfur compound, Ammonium persulfate, sodium persulfate, sodium hydrogensulfite Examples of cerium compounds include cerium fluoride, cerium chloride, cerium oxide, cerium hydroxide, cerium carbonate, cerium sulfate, and cerium oxalate. Examples of tellurium compounds include tellurium chloride. Can be mentioned.

  In particular, among these compounds, oxides that can obtain uniform fine particles at low cost and have a high plating suppression effect are preferable. In the present invention, suitable precipitation inhibiting components include zinc oxide, mercuric oxide, boron trioxide, diboron trioxide, aluminum oxide, silicon dioxide, germanium oxide, stannous oxide, stannic oxide, cerium oxide, and the like. In particular, silicon dioxide, diboron trioxide and the like are preferable.

  The plating deposition inhibiting composition used in the present invention is preferably in the form of using a droplet discharge method as a method of disposing on the substrate. In this case, various additives may be added in order to adjust various physical properties of the precipitation inhibiting composition to those preferable for ejection by the droplet ejection method. Here, examples of various physical properties include surface tension, viscosity, and contact angle with respect to the substrate.

(Electroless plating treatment)
In the electroless plating treatment used in the present invention, a metal wiring pattern is formed by depositing metal ions contained in a plating solution using a catalyst disposed on a substrate as a nucleus. The plating solution that can be used in the plating treatment is a solution in which metal ions to be deposited as a plating material are dissolved. The plating solution contains a metal salt and a reducing agent. A known electroless plating solution is used without any particular limitation. be able to.

  Examples of metal salts contained in the plating solution include halides, nitrates, sulfates, phosphates, borates, acetic acids of at least one metal selected from Au, Ag, Cu, Ni, Co, and Fe. Salt, tartrate, citrate and the like.

  As the reducing agent, hydrazine, hydrazine salt, borohalide salt, hypophosphite, hyposulfite, alcohol, aldehyde, carboxylic acid, carboxylate and the like are applicable. Elements such as boron, phosphorus and nitrogen contained in these reducing agents may be precipitated and contained together with the metal. Or you may take the form which an alloy precipitates using the plating solution containing 2 or more types of metal salts.

  The plating solution may contain additives such as a buffer for adjusting pH and a surfactant as necessary. Moreover, you may make it add organic solvents, such as alcohol, a ketone, and ester other than water as a solvent.

  The composition of the plating solution is composed of a metal salt of the metal to be deposited, a reducing agent, and an additive and an organic solvent as necessary, but the concentration and composition can be adjusted according to the deposition rate. . In addition, the deposition rate can be adjusted by adjusting the temperature of the plating solution. Examples of the temperature adjusting method include a method of adjusting the temperature of the plating solution, and a method of adjusting the temperature by heating and cooling the substrate before immersion, for example, when immersed in the plating solution. Furthermore, the film thickness of the metal which deposits by the time immersed in a plating solution can also be adjusted.

  Moreover, it is preferable to pre-process a board | substrate before processing the board | substrate with which the catalyst is arrange | positioned with a plating solution. Examples of the pretreatment include heat drying treatment of the substrate, cleaning treatment, catalyst activation treatment, and the like, and a known treatment method may be selected as necessary to carry out the treatment.

  Further, after the electroless plating process is performed to form a wiring pattern, electroplating may be further performed to increase the thickness of the wiring. In this case, it is preferable that a pattern for use as an electrode for use in energization when performing electroplating is formed with ink in the same manner as the wiring pattern.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

(Base material, base layer)
The surface of the polyimide film (Kapton 500H manufactured by Toray DuPont) was subjected to a corona discharge treatment of 12 W · min / m ² for 2 seconds, and then an acrylic latex coating solution (copolymer of formula 1 below, molar ratio a: b: c: d = 30: 20: 25: 25, solid content 30% by mass, dispersion medium; water) was applied with a wire bar so that the dry film thickness was 1 μm. After application, the substrate was dried in a constant temperature bath at 100 ° C. for 2 minutes to produce a base layer on the substrate.

(Ink with catalytic ability)
<Ink composition>
Ag colloidal fine particles with an average particle diameter of 20 nm 5% by mass
(Including 1.5% by mass of protective colloid component)
Pd colloidal fine particles with an average particle size of 50 nm 15% by mass
(Contains 3% by mass of protective colloid component)
80% by mass of triethylene glycol monomethyl ether
(Insulating layer composition)
1)
Triethylene glycol monomethyl ether 50% by mass
Acrylic resin 50% by mass
2)
Triethylene glycol monomethyl ether 40% by mass
Acrylic resin 40% by mass
Precipitation inhibiting component (*) 20% by mass
(* Inhibiting components: (a) silicon dioxide, (b) diboron trioxide, (c) zinc oxide)
(Droplet ejection method, catalyst ink drawing)
Using the droplet discharge device shown in FIG. 6, the catalyst ink was discharged onto the substrate on which the underlayer was formed to produce an ink pattern.

(Evaluation of drive voltage)
Prior to discharging ink onto the substrate, in order to determine the drive voltage Ve of the piezoelectric element provided in the droplet discharge head, the discharge state of the droplet when the drive voltage is changed is observed, The values of V1 and V2 were confirmed for each nozzle. In all the nozzles observed, the value of V2 was about 1.5 times the value of V1.

  Thereafter, ink was ejected with various changes in Ve to form an ink pattern.

  The produced ink pattern is formed by forming a plurality of straight lines having a line width of 20 μm with a line interval of 50 μm.

(Arrangement of deposition inhibiting components on the substrate)
The insulating layer composition was discharged onto the substrate on which the ink pattern was formed using the droplet discharge device shown in FIG. When discharging, the composition was controlled so as not to be disposed on the ink pattern.

  Then, it was made to dry for 2 minutes with a 100 degreeC thermostat.

(Electroless plating treatment)
Next, an electroless plating process was performed by the following steps to obtain a copper wiring pattern.

<Plating process>
Degreasing: immersing in a 50 g / L aqueous solution at 50 ° C. for 3 minutes in a degreasing agent for immersion degreasing (A Screen A-220, manufactured by Okuno Pharmaceutical Co., Ltd.).

  Etching: Immersion in an aqueous solution containing 400 g / L of chromic anhydride and 400 g / L of 98% sulfuric acid at 70 ° C. for 10 minutes.

  Neutralization: Immersion in a 10 ml / L aqueous solution of CRP Neutralizer 300 (Okuno Pharmaceutical Co., Ltd.) for 3 minutes at room temperature.

  Pre-dip: Immerse in a 50% / L aqueous solution of 35% hydrochloric acid for 1 minute at room temperature.

  Catalysis: Immersion in an aqueous solution containing 30 ml / L of palladium-tin colloid (CRP Catalyst K, manufactured by Okuno Pharmaceutical Co., Ltd.) and 250 ml / L of 35% hydrochloric acid at 30 ° C. for 6 minutes.

  Conductive (electroless copper plating): 45 conductive film-forming aqueous solution containing Cu (electroless copper plating solution) (CRP selector A 150 ml / L, CRP selector B 200 ml / L, manufactured by Okuno Pharmaceutical Co., Ltd.) Immerse for 3 minutes at ℃.

(Evaluation methods)
The board | substrate with which the wiring pattern was formed was observed with the microscope, and the following items were evaluated.

(1) Wiring width variation The line widths at arbitrary 50 locations of the formed wiring were measured, the average line width and the line width variation degree were calculated according to the following calculation formula, and evaluated based on the following rank criteria.

Average line width: Wave = (W1 + W2 +... + W50) / 50 × 100
(W1, W2,... Represent the line width of the first measurement position, the line width of the second measurement position,...)
Line width variation = (| W1-Wave | + | W2-Wave | +... + | W50−Wave |) / 50 × 100
(The smaller the value of the line width variation degree, the more uniform and preferable the line width.)
<Evaluation criteria>
○: Line width variation is less than 1%.
Δ: Line width variation is 1% or more and less than 5%.
X: Line width variation is 5% or more.

(2) Precipitation of copper at a position other than the ink pattern By visual observation, the deposition state of copper at a position other than the wiring pattern was evaluated based on the following rank criteria.

<Evaluation criteria>
○: No copper deposition is observed at positions other than the ink pattern.
Δ: Although copper is slightly deposited at positions other than the ink pattern, it is at a level without any actual harm.
X: A large amount of copper is deposited at positions other than the ink pattern, and there is a place where adjacent wiring patterns are short-circuited.

  The evaluation results are shown in Table 1.

  As is apparent from the results shown in Table 1, it can be seen that by adopting the wiring pattern forming method of the present invention, it is possible to form a highly reliable circuit pattern by preventing plating deposition on unintended portions. .

Schematic diagram showing an example of a droplet discharge head Schematic showing a cross section of an example of a droplet discharge head Schematic diagram showing the relationship between the drive voltage Ve of the piezoelectric element and the behavior of the liquid in the discharge hole Schematic diagram showing an example of the waveform of the drive voltage Ve when discharging a droplet Schematic diagram showing an example of the waveform of the drive voltage Ve when discharging a droplet Schematic diagram showing the overall configuration of the liquid ejection device

Explanation of symbols

A Inkjet recording head 1 Nozzle plate 2 Body plate 3 Pressure generating means 11 Ejection hole for ink ejection 21 Ink supply port 22 Common ink chamber groove 23 Ink supply path groove 24 Pressure chamber groove serving as pressure chamber 60 Liquid ejection device

Claims (9)

A method for forming a wiring pattern by a droplet discharge method, wherein an ink pattern is formed by disposing an ink containing a composition exhibiting a function as a catalyst for electroless plating on a substrate by a droplet discharge method And a step of depositing a plating metal on the ink pattern by performing an electroless plating process on the substrate on which the ink pattern is formed, and the droplet discharge method includes a nozzle plate having discharge holes, and a discharge hole. It is a method of discharging droplets from a droplet discharge head comprising a communicating pressure chamber, a pressure generating element that causes a pressure fluctuation in a liquid in the pressure chamber, and a driving voltage applying unit that applies a voltage to the pressure generating element. A wiring pattern forming method, wherein the voltage Ve applied to the drive voltage applying means when discharging the droplet satisfies the following relational expression.
Relational expression: V1 <Ve <V2
(V1 is the maximum voltage at which the liquid rises from the discharge hole but returns to the discharge hole without forming a droplet, and V2 is the minimum voltage at which the droplet discharged from the discharge hole splits into multiple parts during flight. .) The method for forming a wiring pattern according to claim 1, wherein the ink is an ink containing fine metal particles having electroless plating catalytic ability. 3. The method of forming a wiring pattern according to claim 1, wherein the droplet discharge method is a method of flying droplets using electrostatic force in addition to the action of the pressure fluctuation. The method for forming a wiring pattern according to any one of claims 1 to 3, further comprising a step of providing a base layer on the substrate prior to forming the ink pattern on the substrate. 5. The wiring pattern forming method according to claim 1, further comprising a step of disposing an insulating layer at a position where the ink pattern of the substrate is not formed. 6. 6. The method for forming a wiring pattern according to claim 5, wherein the step of disposing the insulating layer is performed by a droplet discharge method. The method for forming a wiring pattern according to claim 5, wherein the insulating layer contains a plating deposition inhibiting component as a constituent component thereof. The insulating layer is composed of a compound containing a Group 12 element, a compound containing a Group 13 element, a compound containing a Group 14 element, and a compound containing a Group 16 element as the plating deposition inhibiting component. The method for forming a wiring pattern according to claim 7, comprising a compound selected from the group. A wiring board having a wiring pattern formed by the method for forming a wiring pattern according to claim 1.

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