JP2007027454A - Wiring pattern forming method, wiring pattern, wiring board, electro-optical device, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring pattern forming method, a wiring pattern, a good quality wiring board, an electro-optical device, and an electronic apparatus capable of further improving insulation.
A wiring substrate 10 is formed by arranging a first functional liquid X1 containing a wiring pattern material on a substrate P, and solidifying the arranged first functional liquid X1 to form a wiring 13. . Next, the plating layer 14 is formed so as to cover the wiring 13 and the wiring pattern 30 is formed. Finally, the second functional liquid X2 as an insulating material is arranged between the wirings 13, and the arranged second functional liquid X2 is solidified to form the insulating layer 33.
[Selection] Figure 1

Description

  The present invention relates to a wiring pattern forming method, a wiring pattern, a wiring board, an electro-optical device, and an electronic apparatus.

  With advances in technology such as downsizing, weight reduction, and high performance of electronic devices, semiconductor circuits have been miniaturized, and there has been a demand for higher density circuit boards. As the density of circuit boards increases, a technique for finely forming a wiring pattern made of a conductor and an insulating pattern made of an insulator for filling the space between the wirings of the wiring pattern has been required. ing. Therefore, in order to cope with the higher density of the circuit board, it is necessary to narrow the interval between the wirings of the wiring pattern, and it is important to ensure the insulation of the wiring pattern.

  For example, as disclosed in Patent Document 1, curable ink is ejected and arranged on the surface of a substrate on which a wiring pattern is formed so as to fill between the wirings of the wiring pattern, and the arranged ink is cured. Therefore, a method for forming an electrical insulating layer by laminating and curing a film-like or sheet-like curable molding has been proposed.

JP 2004-200233 A

  However, in this method, since a sheet-like curable product is laminated on the wiring pattern, there is a possibility that migration may occur if water permeates through the gap where the sheet is adhered. Further, in the case of a wiring pattern in which components are joined to the wiring, the wiring pattern is exposed and cannot be covered with a sheet. If the wiring pattern cannot be covered with a sheet, moisture may adhere to the wiring pattern and migration may occur. When migration occurs, the insulation resistance value between the wiring patterns changes. As a result, it is difficult to ensure the insulation of the wiring pattern. For example, there is a risk of dielectric breakdown in a wiring board or the like.

  An object of the present invention is to provide a wiring pattern forming method, a wiring pattern, a good quality wiring substrate, an electro-optical device, and an electronic apparatus, which can further improve insulation.

  The wiring pattern forming method of the present invention is a method of forming a wiring pattern on a substrate by using a droplet discharge method, wherein a first functional liquid containing the material of the wiring pattern is disposed on the substrate. Solidifying the first functional liquid formed to form a wiring; forming a plating layer so as to cover the wiring; and a second functional liquid including an insulating material between the wirings of the wiring. And a step of solidifying the arranged second functional liquid to form an insulating layer.

  According to the present invention, the plating layer is formed so as to cover not only the surface of the wiring but also the side surface of the wiring, and the insulating layer is also formed so as to close a minute gap between the substrate and the plating layer. Therefore, even if moisture is adsorbed on the wiring pattern, the wiring can be protected, so that the migration resistance can be improved. If the migration resistance is improved, the insulation of the wiring pattern can be improved.

  In the wiring pattern forming method of the present invention, in the step of forming the plating layer, the plating layer is preferably formed by laminating a first plating layer and a second plating layer on the first plating layer. .

  According to this invention, since the plating layer is formed by laminating the first plating layer and the second plating layer, the wiring can be protected by the first plating layer and the second plating layer. Migration resistance can be further improved. If the migration resistance is further improved, the insulation of the wiring pattern can be further improved.

  In the wiring pattern forming method of the present invention, it is desirable to form the plating layer made of Au in the step of forming the plating layer.

  According to the present invention, since the Au plating layer is formed on the wiring, in addition to protecting the wiring, since Au is a material having good conductivity, the connectivity between the wiring pattern and the component can be improved. Can do. Moreover, since Au is difficult to oxidize, it can be easily soldered.

  In the wiring pattern forming method of the present invention, in the step of forming the plating layer, the first plating layer made of Ni, the second plating layer made of Au, and the wiring made of Ag. It is desirable to form the plating layer by laminating the layers.

  According to the present invention, since the first plating layer is Ni, it is possible to prevent the diffusion of Ag, which is a wiring material, so that the migration resistance can be further improved. In addition, since the second plating layer is Au, since Au is a material having good conductivity, the connectivity between the wiring pattern and the component can be improved. Moreover, since Au is difficult to oxidize, it can be easily soldered.

  In the wiring pattern forming method of the present invention, in the step of forming the insulating layer, it is desirable to form the insulating layer so as to cover the upper surface of the wiring pattern at a place other than the terminal portion.

  According to this invention, since the insulating layer is formed so as to cover the upper surface of the wiring pattern except for the terminal portion, the sheet-like curable product is not laminated on the wiring pattern as in the prior art. However, insulation can be obtained. In addition, since the insulating layer is not formed on the terminal portion, it can be joined to the component.

  A method for manufacturing a wiring board according to the present invention is a method for manufacturing a wiring board in which a wiring pattern is formed on a substrate by using a droplet discharge method, and the wiring pattern forming method described above is formed on the substrate. And forming the wiring pattern.

  According to the present invention, since the above-described wiring pattern is provided, the migration resistance is improved, so that a wiring board with improved insulation can be formed. If the insulation of the wiring board is improved, the wiring pattern can be densified, so that a wiring board that can be reduced in size and weight can be formed.

  The wiring board of the present invention is a wiring board on which a wiring pattern is formed using a droplet discharge method, and covers the wiring, a plating layer formed so as to cover the wiring, and the plating layer. And an insulating layer formed as described above.

  According to this invention, since the wiring is protected by the plating layer and the insulating layer, it is possible to provide a wiring board with improved migration resistance. Since the migration resistance is improved, a wiring board with improved insulation can be provided.

  The wiring board of the present invention is formed by using the wiring board manufacturing method described above.

  According to the present invention, since the above-described wiring pattern is provided, the migration resistance is improved, so that a wiring board with improved insulation can be provided. If the insulation is improved, the wiring pattern can be densified, so that a wiring board that can be reduced in size and weight can be provided.

  An electro-optical device according to the present invention includes the wiring board described above.

  According to this invention, since the wiring board with improved insulation is provided, an electro-optical device with improved quality can be provided. In addition, since the wiring board has a high density and can be reduced in size and weight, an electro-optical device that can be reduced in size and weight can be provided.

  An electronic apparatus according to the present invention includes the electro-optical device described above.

  According to the present invention, since the electro-optical device with improved quality is provided, a high-quality electronic device can be provided. In addition, since the electro-optical device can be reduced in size and weight, an electronic device that can be reduced in size and weight can be provided.

(First embodiment)
In this embodiment, a wiring pattern formed on a substrate by a droplet discharge method will be described. A plating layer is formed on the wiring.

  FIG. 1 is a schematic view showing an example of a wiring board 10 in the present embodiment. A wiring board 10 of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the wiring board 10 includes a wiring pattern 30 and an insulating layer 33 formed on the board P. The wiring pattern 30 includes a wiring 13 and a plating layer 14, and the plating layer 14 is formed by laminating a first plating layer 14a and a second plating layer 14b.

  The material of the substrate P is a resin material such as polyimide. The material of the wiring 13 is Ag, which is a conductor, in order to ensure its electrical characteristics. The material of the first plating layer 14a is Ni with good corrosion resistance. The material of the second plating layer 14b is soft and Au having good conductivity. The first plated layer 14a made of Ni with good corrosion resistance can prevent the migration of the wiring 13, and the second plated layer 14b made of Au with good conductivity is easy to solder. The plating layer 14 may be a single layer. For example, migration can be prevented if the material is Au and the Au plating layer 14 is formed thick.

  The insulating layer 33 is formed so as to fill the space between the wirings 13. The material for forming the insulating layer 33 is an acrylic resin insulating material. When the plating layer 14 is formed on the wiring 13, it is difficult for the plating to adhere to the substrate P compared to the wiring 13, so that a minute gap 19 is generated between the substrate P and the plating layer 14. However, the insulating layer 33 is formed so as to close the gap 19.

Next, the functional liquid for wiring, the substrate, the droplet discharge method, and the droplet discharge device for forming the wiring substrate 10 will be described sequentially.
<Functional fluid for wiring>

  First, the wiring functional liquid as the wiring material will be described. The functional liquid for wiring, which is a liquid material, is a dispersion liquid in which conductive fine particles are dispersed in a dispersion medium. In this embodiment, Ag is used as the conductive fine particles. Other conductive fine particles include, for example, metal fine particles containing at least one of gold, copper, aluminum, palladium, and nickel, oxides thereof, and fine particles of conductive polymers and superconductors. Used. These conductive fine particles can be used by coating the surface with an organic substance or the like in order to improve dispersibility. The particle diameter of the conductive fine particles is preferably 1 nm or more and 1.0 μm or less. If it is larger than 1.0 μm, clogging may occur in the discharge nozzle of the droplet discharge head 1 described later. On the other hand, if it is smaller than 1 nm, the volume ratio of the coating agent to the conductive fine particles becomes large, and the ratio of the organic matter in the obtained film becomes excessive.

  The dispersion medium is not particularly limited as long as it can disperse the conductive fine particles and does not cause aggregation. For example, in addition to water, alcohols such as methanol, ethanol, propanol, butanol, n-heptane, n-octane, decane, dodecane, tetradecane, toluene, xylene, cymene, durene, indene, dipentene, tetrahydronaphthalene, decahydro Hydrocarbon compounds such as naphthalene and cyclohexylbenzene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, 1,2-dimethoxyethane, bis (2- Methoxyethyl) ether, ether compounds such as p-dioxane, propylene carbonate, γ- Butyrolactone, N- methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, can be exemplified polar compounds such as cyclohexanone. Of these, water, alcohols, hydrocarbon compounds, and ether compounds are preferable and more preferable dispersion media in terms of fine particle dispersibility, dispersion stability, and ease of application to the droplet discharge method. Examples thereof include water and hydrocarbon compounds.

  The surface tension of the conductive fine particle dispersion is preferably in the range of 0.02 N / m to 0.07 N / m. When ejecting droplets by the droplet ejection method, if the surface tension is less than 0.02 N / m, the wettability of the droplets with respect to the nozzle surface increases, and flight bending tends to occur. If it exceeds 0.07 N / m, the shape of the meniscus at the nozzle tip is not stable, and it becomes difficult to control the discharge amount and the discharge timing. In order to adjust the surface tension, a small amount of a surface tension regulator such as a fluorine-based, silicone-based, or nonionic-based material may be added to the dispersion liquid as long as the contact angle with the substrate P is not greatly reduced. The nonionic surface tension adjusting agent improves the wettability of the functional liquid for wiring to the substrate P, improves the leveling property of the film, and helps prevent the occurrence of fine irregularities on the film. The surface tension modifier may contain an organic compound such as alcohol, ether, ester, or ketone, if necessary.

The viscosity of the dispersion is preferably 1 mPa · s or more and 50 mPa · s or less. When the functional liquid for wiring is ejected as droplets using the droplet ejection method, if the viscosity is less than 1 mPa · s, the nozzle periphery is easily contaminated by the outflow of ink, and the viscosity is greater than 50 mPa · s. In this case, the clogging frequency in the nozzle holes increases, and it becomes difficult to smoothly discharge the droplets.
<Board>

As the substrate P, various materials such as glass, quartz glass, Si wafer, plastic film, metal plate, and ceramic can be used. When a Si wafer or a metal plate is used, an insulating film is required for the base. In addition, a substrate in which a semiconductor film, a metal film, a dielectric film, an organic film, an insulating film or the like is formed as a base layer on the surface of these various material substrates is also included.
<Droplet ejection method>

Examples of the discharge technique of the droplet discharge method include a charge control method, a pressure vibration method, an electromechanical conversion method, an electrothermal conversion method, and an electrostatic suction method. Here, in the charge control method, a charge is applied to a material by a charging electrode, and the flight direction of the material is controlled by a deflection electrode and discharged from a discharge nozzle. Also, pressure vibration method is intended to discharge the material to the nozzle tip side by application of ultra-high pressure of about 30kg / cm ² on the material from the discharge nozzle and the material goes straight when not applying a control voltage When discharged and a control voltage is applied, electrostatic repulsion occurs between the materials, and the materials are scattered and are not discharged from the discharge nozzle. The electromechanical conversion method utilizes the property that a piezoelectric element (piezoelectric element) is deformed by receiving a pulse-like electric signal. The piezoelectric element is deformed through a flexible substance in a space where material is stored. Pressure is applied, and the material is extruded from this space and discharged from the discharge nozzle.

In the electrothermal conversion method, a material is rapidly vaporized by a heater provided in a space in which the material is stored to generate bubbles, and the material in the space is discharged by the pressure of the bubbles. In the electrostatic attraction method, a minute pressure is applied to a space in which a material is stored, a meniscus of material is formed on the discharge nozzle, and an electrostatic attractive force is applied in this state before the material is drawn out. In addition to this, techniques such as a system that uses a change in the viscosity of a fluid by an electric field and a system that uses a discharge spark are also applicable. The droplet discharge method has an advantage that the use of the material is less wasteful and a desired amount of the material can be accurately disposed at a desired position. In addition, the amount of one drop of the liquid material discharged by the droplet discharge method is 1 to 300 nanograms, for example.
<Droplet ejection device>

  Next, an example of a droplet discharge device that discharges a liquid material using the above-described droplet discharge method will be described. In the present embodiment, a description will be given by using a droplet discharge device IJ that discharges (drops) droplets from the droplet discharge head 1 onto the substrate P using a droplet discharge method.

FIG. 2 is a perspective view showing a schematic configuration of the droplet discharge device IJ.
In FIG. 2, the droplet discharge device IJ includes a droplet discharge head 1, an X-axis direction drive shaft 4, a Y-axis direction guide shaft 5, a control device CONT, a stage 7, a cleaning mechanism 8, and a base. 9 and a heater 15.
The stage 7 supports the substrate P on which the liquid material is arranged by the droplet discharge device IJ, and includes a fixing mechanism (not shown) that fixes the substrate P to a reference position.

  The droplet discharge head 1 is a multi-nozzle type droplet discharge head having a plurality of discharge nozzles, and the longitudinal direction and the X-axis direction are made to coincide. The plurality of discharge nozzles are provided on the lower surface of the droplet discharge head 1 at regular intervals. A liquid material is discharged from the discharge nozzle of the droplet discharge head 1 onto the substrate P supported by the stage 7.

An X-axis direction drive motor 2 is connected to the X-axis direction drive shaft 4. The X-axis direction drive motor 2 is a stepping motor or the like, and rotates the X-axis direction drive shaft 4 when a drive signal in the X-axis direction is supplied from the control device CONT. When the X-axis direction drive shaft 4 rotates, the droplet discharge head 1 moves in the X-axis direction.
The Y-axis direction guide shaft 5 is fixed so as not to move with respect to the base 9. The stage 7 includes a Y-axis direction drive motor 3. The Y-axis direction drive motor 3 is a stepping motor or the like, and moves the stage 7 in the Y-axis direction when a drive signal in the Y-axis direction is supplied from the control device CONT.

The control device CONT supplies the droplet discharge head 1 with a voltage for controlling droplet discharge. In addition, a drive pulse signal for controlling the movement of the droplet discharge head 1 in the X-axis direction is supplied to the X-axis direction drive motor 2, and a drive pulse signal for controlling the movement of the stage 7 in the Y-axis direction is sent to the Y-axis direction drive motor 3. Supply.
The cleaning mechanism 8 cleans the droplet discharge head 1. The cleaning mechanism 8 is provided with a Y-axis direction drive motor (not shown). The cleaning mechanism 8 moves along the Y-axis direction guide shaft 5 by driving the Y-axis direction drive motor. The movement of the cleaning mechanism 8 is also controlled by the control device CONT.
Here, the heater 15 is a means for heat-treating the substrate P by lamp annealing, and evaporates and dries the solvent contained in the liquid material disposed on the substrate P. The heater 15 is also turned on and off by the control device CONT.

  The droplet discharge device IJ has a plurality of arrays arranged in the X-axis direction on the lower surface of the droplet discharge head 1 with respect to the substrate P while relatively scanning the droplet discharge head 1 and the stage 7 supporting the substrate P. Droplets are discharged from the discharge nozzle.

FIG. 3 is a view for explaining the discharge principle of the liquid material by the piezo method.
In FIG. 3, a piezo element 22 is installed adjacent to a liquid chamber 21 for storing a liquid material. The liquid material is supplied to the liquid chamber 21 via a liquid material supply system 23 including a material tank that stores the liquid material. The piezo element 22 is connected to a drive circuit 24, and the liquid chamber 21 is deformed by applying a voltage to the piezo element 22 via the drive circuit 24 to deform the piezo element 22. When the liquid chamber 21 is restored to the original state, the liquid material is discharged from the discharge nozzle 25. In this case, the amount of distortion of the piezo element 22 is controlled by changing the value of the applied voltage. Further, the strain rate of the piezo element 22 is controlled by changing the frequency of the applied voltage. Since the droplet discharge by the piezo method does not apply heat to the material, it has an advantage of hardly affecting the composition of the material.

  The liquid droplet ejection apparatus described above can be used in the arrangement method and the manufacturing method according to the present invention. However, the present invention is not limited to this, and a liquid droplet is ejected and a predetermined landing position is expected. Any device can be used as long as it can be landed.

  A method for forming the wiring board 10 will be described below.

  FIGS. 4A to 4D and FIGS. 5E to 5G are diagrams showing the manufacturing process of the wiring board 10, and FIG. 6 is a schematic flowchart showing the procedure of the manufacturing process of the wiring board 10. It is.

A method for forming the wiring board 10 of the present invention will be described with reference to FIGS. In addition, the formation method of the wiring board 10 of this embodiment includes a substrate cleaning process, a substrate surface treatment process, a wiring functional liquid arrangement process, a wiring functional liquid solidification process, a plating layer formation process, an insulating functional liquid arrangement process, It is roughly composed of a drying process and an insulating functional liquid solidification process. Hereinafter, each step will be described in detail.
(Substrate cleaning process)

In step S1 of FIG. 6, the substrate P is cleaned. In order to satisfactorily perform the liquid repellency treatment of the substrate P, it is preferable to perform cleaning as a pretreatment step of the liquid repellency treatment. As a method for cleaning the substrate P, for example, ultraviolet cleaning, ultraviolet / ozone cleaning, plasma cleaning, acid or alkali cleaning, or the like can be employed. In addition, the board | substrate P used the polyimide.
(Substrate surface treatment process)

  In step S2 of FIG. 6, as shown in FIG. 4A, the surface of the substrate P is surface-treated. The surface treatment of the substrate P is to make the surface of the substrate P liquid repellent so as to obtain a contact angle necessary for reducing the landing diameter of the functional liquid X1 for wiring. As a method for making the surface of the substrate P lyophobic, a method of forming an organic thin film on the surface of the substrate P, a plasma treatment method, or the like can be employed. Here, a method of forming an organic thin film was adopted. And the surface of the board | substrate P is provided with liquid repellency.

  In the method of forming an organic thin film as the liquid repellency treatment of the substrate P, an organic thin film is formed from organic molecules such as a silane compound and a surfactant on the surface of the substrate P on which the wiring pattern 30 is to be formed. The organic molecules for treating the surface of the substrate P modify the surface properties of the substrate such as a functional group that can be physically or chemically bonded to the substrate P and a liquid repellent group on the opposite side (control the surface energy). It has a functional group and binds to the substrate P to form an organic thin film, which is ideally a monomolecular film. As another method, only the region where the wiring 13 is formed on the substrate P may be given lyophilicity, and the other region may be given liquid repellency.

On the other hand, in the plasma processing method, plasma irradiation is performed on the substrate P under normal pressure or vacuum. Various types of gas used for the plasma treatment can be selected in consideration of the surface material of the substrate P on which the wiring pattern 30 is to be formed. As the processing gas, a fluorocarbon-based compound can be preferably used, and examples thereof include tetrafluoromethane, perfluorohexane, and perfluorodecane. The processing conditions of the plasma processing method (CF ₄ plasma processing method) using tetrafluoromethane as a processing gas are, for example, a plasma power of 50 to 1000 W, a carbon tetrafluoride gas flow rate of 50 to 100 mL / min, and a substrate for the plasma discharge electrode. The conveyance speed is 0.5 to 1020 mm / sec, and the substrate temperature is 70 to 90 ° C.
(Functional liquid placement process for wiring)

In step S3 of FIG. 6, as shown in FIG. 4B, a functional liquid X1 for wiring as a wiring material is ejected from the liquid droplet ejection head 1 on the substrate P by using the liquid droplet ejection device IJ. Drop 11 is placed. In addition, as conditions for droplet discharge, for example, the droplet weight can be 4 ng / dot, and the droplet speed (discharge speed) can be 5 to 7 m / sec. Moreover, it is preferable that the atmosphere when discharging droplets is set to a temperature of 60 ° C. or lower and a humidity of 80% or lower. Thereby, it is possible to perform stable droplet discharge without clogging the discharge nozzle of the droplet discharge head 1. The wiring functional liquid X1 contains Ag as conductive fine particles. Since the liquid repellency is imparted on the substrate P, the discharged functional liquid X1 for wiring is easily repelled on the substrate P, and a liquid material having a predetermined length is disposed. The cross-sectional shape of the disposed liquid material is likely to be a substantially kamaboko shape.
(Functional liquid solidification process for wiring)

  Next, in step S4 of FIG. 6, as shown in FIG. 4C, the droplet 11 disposed on the substrate P is dried. After disposing the droplets 11 on the substrate P, a drying process is performed as necessary to remove the dispersion medium and secure the film thickness. A liquid film is then formed. The drying process can be performed by lamp annealing, for example, in addition to a process using a normal hot plate or an electric furnace for heating the substrate P. The light source used for lamp annealing is not particularly limited, but excimer lasers such as infrared lamps, xenon lamps, YAG lasers, argon lasers, carbon dioxide lasers, XeF, XeCl, XeBr, KrF, KrCl, ArF, ArCl, etc. It can be used as a light source. In general, these light sources have an output in the range of 10 W to 5000 W, but in the present embodiment, a range of 100 W to 1000 W is sufficient.

  In the case of a liquid film containing Ag, it is necessary to solidify by heat treatment in order to obtain conductivity. Therefore, the substrate P is subjected to heat treatment and / or light treatment.

The heat treatment and / or light treatment is usually performed in the air, but if necessary, it can also be performed in an inert gas atmosphere such as nitrogen, argon or helium, or in a reducing atmosphere such as hydrogen. The treatment temperature of heat treatment and / or light treatment depends on the boiling point (vapor pressure) of the dispersion medium, the type and pressure of the atmospheric gas, the thermal behavior such as fine particle dispersibility and oxidation, the presence and amount of coating material, It is determined appropriately in consideration of the heat resistant temperature. In this embodiment, a solidification process is performed on the droplets 11 containing Ag conductive fine particles. When the organic silver compound is contained, it is preferable that the processing temperature is 100 ° C. or higher and the processing time is 30 minutes or longer in order to remove the organic component of the organic silver compound from the arranged droplets 11. As described above, electrical contact between the Ag fine particles is ensured, and the conductive wiring 13 is formed. The formed wiring 13 has a thickness in the range of 5 to 10 μm.
(Plating layer forming process)

  Next, in step S5 of FIG. 6, as shown in FIG. 4D, the plating layer 14 is laminated on the wiring 13 formed on the substrate P to form a wiring pattern 30. The plating layer 14 includes a first plating layer 14a and a second plating layer 14b.

  The first plating layer 14a is formed on the wiring 13 by a method such as electroless plating or electrolytic plating. For example, after applying a Pd catalyst on the wiring 13, the first plating layer 14a is formed. By doing so, the first plating layer 14a can be grown. The material of the first plating layer 14a is Ni, and since Ni has good corrosion resistance, it is possible to suppress the diffusion of Ag of the material forming the wiring 13. In addition, the film thickness of the 1st plating layer 14a is the range of 0.5 micrometer-5 micrometers.

  Similarly, the second plating layer 14b is formed on the first plating layer 14a by a method such as electroless plating or electrolytic plating. A plating layer 14 composed of the first plating layer 14 a and the second plating layer 14 b is formed on the wiring 13. Since the second plating layer 14b is Au, the electric resistance value is small and the conductivity is excellent. Moreover, since Au is easy to adapt to solder, it has excellent solderability. Moreover, since it is soft, it has excellent bonding properties when connecting an IC package or the like with a thin wire such as Au or aluminum. In addition, the 2nd plating layer 14b is the range of 0.01 micrometer-2 micrometers. Therefore, the plating layer 14 is in the range of 0.51 m to 7 μm. Here, since the material of the wiring 13 is Ag and the material of the substrate P is polyimide, the substrate P is more difficult to plate than the wiring 13, so that a fine gap 19 is generated between the substrate P and the plating layer 14. There is.

The plated layer 14 in the present embodiment has a configuration in which the first plated layer 14a and the second plated layer 14b are laminated. However, the plated layer 14 may be a single layer, for example. In the case of a single layer, the material may be Au and the plating layer 14 may be formed thick. Note that the thickness of the plating layer 14 in a single layer is desirably about 1 μm. If the thickness of the plating layer 14 is secured to some extent and if it is a single layer, the manufacturing method is simplified, so that the wiring substrate 10 can be formed easily. In addition, since Au is used as the material and a certain degree of film thickness is secured, the wiring substrate 10 with good conductivity and solderability can be obtained. In addition, it is possible to use a single Au layer because a process that diffuses Ag selected as a wiring material is not performed, or if the wiring 13 is made of a material other than Ag, the wiring 13 is not diffused.
(Functional liquid placement process for insulation)

Next, in step S6 of FIG. 6, as shown in FIG. 5E, the insulating material functional liquid X2 containing the insulating material is applied from the droplet discharge head 1 onto the substrate P using the droplet discharge device IJ. The liquid droplets 31 are disposed in the recess 16 by discharging. In addition, as conditions for droplet discharge, for example, the droplet weight can be 4 ng / dot, and the droplet speed (discharge speed) can be 5 to 7 m / sec. The atmosphere for discharging the droplets is preferably set to a temperature of 60 ° C. or lower and a humidity of 80% or lower. Thereby, it is possible to perform stable droplet discharge without clogging the discharge nozzle of the droplet discharge head 1. The insulating material functional liquid X2 is, for example, an acrylic resin. It is also possible to use a polymer material such as a polyimide resin, an olefin resin, a phenol resin, or a melamine resin. When the insulating material functional liquid X2 is discharged into the recess 16, the insulating material functional liquid X2 enters the minute gap 19 between the substrate P and the plating layer 14, and the gap 19 is filled. Then, when the insulating material functional liquid X2 is continuously discharged into the recess 16, the droplet 31 is disposed so that the substrate P and the side surface of the plating layer 14 can be protected. The insulating material functional liquid X2 may be disposed so as to cover the plating layer 14. In this way, the wiring 13 can be further protected.
(Drying process)

Next, in step S7 of FIG. 6, as shown in FIG. 5 (f), a drying process is performed as necessary to secure the film thickness. For example, the drying process can be performed by lamp annealing in addition to a process using a normal hot plate or an electric furnace for heating the substrate P. The light source used for lamp annealing is not particularly limited, but excimer lasers such as infrared lamps, xenon lamps, YAG lasers, argon lasers, carbon dioxide lasers, XeF, XeCl, XeBr, KrF, KrCl, ArF, ArCl, etc. It can be used as a light source. In general, these light sources have an output in the range of 10 W to 5000 W, but in the present embodiment, a range of 100 W to 1000 W is sufficient. Then, when the droplet 31 is dried, a liquid film 32 of an insulating material is formed.
(Functional liquid solidification process for insulation)

  Next, in step S8 of FIG. 6, as shown in FIG. 5G, the liquid film 32 of the insulating material is cured. The liquid film 32 of the insulating material needs to be solidified in order to maintain the shape. Therefore, the substrate P is subjected to heat treatment and / or light treatment.

  The heat treatment and / or light treatment is usually performed in the air, but if necessary, it can also be performed in an inert gas atmosphere such as nitrogen, argon or helium, or in a reducing atmosphere such as hydrogen. The temperature when solidifying by heat treatment is preferably 100 ° C. or more and the treatment time is 30 minutes or more. Moreover, when solidifying by light treatment, it is preferable to irradiate with ultraviolet rays. Thus, the shape of the liquid film 32 of the insulating material is ensured, and the insulating layer 33 having insulating properties is formed. The thickness of the insulating layer 33 is in the range of 5 to 10 μm, which is the same as that of the wiring 13. Since the wiring layer 13 is protected by the plating layer 14 and the insulating layer 33, migration can be suppressed even if moisture adheres to the wiring pattern 30. Note that migration refers to a state in which moisture is attached to the wiring 13 in a state where current and voltage are applied, and the metal material forming the wiring 13 (in this case, Ag) migrates to the surface of the insulating layer 33 or inside thereof. It is a phenomenon. Then, when migration occurs, the insulation resistance changes and the insulation property decreases.

  In the first embodiment, the following effects can be obtained.

(1) Since the wiring 13 is formed on the substrate P, the plating layer 14 is formed on the wiring 13, and the insulating layer 33 is formed so as to fill the space between the wirings 13, the surface of the wiring 13 In addition, the gap 19 can be closed. Accordingly, the migration resistance can be improved because the wiring pattern 30 is formed by a method that can protect the wiring 13. If the migration resistance is improved, the insulation of the wiring pattern 30 can be improved.
(2) Since the plating layer 14 is formed by laminating the first plating layer 14a and the second plating layer 14b on the wiring 13, the wiring 13 is formed by the first plating layer 14a and the second plating layer 14b. Therefore, migration resistance can be further improved. If the migration resistance is further improved, the insulation of the wiring pattern 30 can be further improved.
(3) Since the first plating layer 14a is Ni, Ni is a material with good corrosion resistance, so that the diffusion of Ag in the wiring 13 can be prevented.
(4) Since the second plating layer 14b is Au, since Au is a material having good conductivity, the connectivity between the wiring 13 and the component can be improved. Furthermore, since Au has good compatibility with solder, soldering can be easily performed.
(Second Embodiment)

  FIG. 7 is a schematic view showing an example of the wiring board 50 in the present embodiment. With reference to FIG. 7, the wiring board 50 of this invention is demonstrated. The material of the substrate P, the wiring material, the insulating material, the plating material, and the like are the same as those in the first embodiment, and thus the description thereof is omitted.

  As shown in FIG. 7, the circuit board 80 (see FIG. 11) has a wiring board 50 and an IC package 65 joined together with solder 63.

  A wiring pattern 60 is formed on the substrate P in the wiring substrate 50. The wiring pattern 60 includes a wiring 55, a plating layer 56, and the like. The wiring board 50 includes a wiring 51 as a first wiring, an insulating layer 52 as a first insulating layer, a conductor post 53, an insulating layer 54 as a second insulating layer, a wiring 55 as a second wiring, a plating layer 56, and the like. It is configured. The plating layer 56 is formed on the wiring 55. The plating layer 56 includes a first plating layer 56a and a second plating layer 56b. The conductor post 53 is formed on the wiring 51. The conductor post 53 serves to connect the wiring 51 and the wiring 55. The insulating layer 57 is formed so as to cover the wiring 55. Since the insulating layer 57 is not formed on the terminal portion, the plating layer 56 of the terminal portion is exposed. The plating layer 56 other than the terminal portion is covered with an insulating layer 57. Further, the insulating layer 57 closes a gap 59 formed between the substrate P and the plating layer 56.

  A method for forming the wiring board 50 will be described below.

  FIGS. 8A to 8D and FIGS. 9E to 9H are diagrams showing manufacturing steps of the wiring board 50 and the circuit board 80, and FIG. 10 shows the wiring board 50 and the circuit board. It is a schematic flowchart which shows the procedure of 80 manufacturing processes.

A method for forming the wiring board 50 and the circuit board 80 of the present invention will be described with reference to FIGS. The materials used to form the wiring substrate 50, the droplet discharge method, the droplet discharge device, the drying method, the solidification method, and the like are the same as those in the first embodiment, and thus description thereof is omitted. In addition, the formation method of the wiring board 50 of the present embodiment includes a first wiring forming step, a first insulating layer forming step, a conductor post forming step, a second insulating layer forming step, a second wiring forming step, a plating layer forming step, The third insulating layer forming step is roughly configured. Furthermore, it is roughly composed of an IC package bonding step for bonding the IC package 65 to the wiring board 50. Hereinafter, each step will be described.
(First wiring formation process)

  In step S11 of FIG. 10, the wiring 51 is formed on the substrate P by photolithography as shown in FIG. 8A. The substrate P has a tape shape. The wiring 51 has a Cu / Ni / Au three-layer structure, a Cu / Au two-layer structure, or a single layer of Cu. These Cu / Ni / Au, Cu / Au, Cu, and the like are preferable because electrical conduction is easily obtained as a wiring material.

  In the case of a three-layer structure of Cu / Ni / Au, Cu is etched on the substrate P by photolithography (for example, using a subtractive method) to form the first layer. Next, the second layer is formed by an electroless plating method or an electrolytic plating method. On the first layer, for example, after applying a Pd catalyst, a second layer is formed. By doing so, Ni of the second layer can be grown. A third layer of Au is formed on the second layer by an electroless plating method or an electrolytic plating method to form the wiring 51.

  In the case of a Cu / Au two-layer structure, the first layer is formed by etching Cu by photolithography (for example, using a subtractive method). Next, a second layer of Au is formed by an electroless plating method or an electrolytic plating method to form the wiring 51.

  In the case of only one layer of Cu, the wiring 51 is formed by etching Cu by photolithography (for example, using a subtractive method).

Note that the method of forming the wiring 51 is not limited to photolithography, and a method of forming such as a droplet discharge method, a vacuum deposition method, or a sputtering method may be employed. The thickness of the formed wiring 51 is in the range of 5 to 10 μm.
(First insulating layer forming step)

Next, in step S12 of FIG. 10, the insulating functional liquid X2 is arranged by the droplet discharge method, and the arranged insulating functional liquid X2 is dried and solidified, as shown in FIG. An insulating layer 52 is formed. The material of the insulating layer 52 is an acrylic resin insulating material. The method for forming the insulating layer 52 is not limited to the droplet discharge method, and a method such as a printing method may be employed. The formed insulating layer 52 has a thickness in the range of 10 to 20 μm.
(Conductor post forming process)

Next, in step S13 of FIG. 10, the wiring functional liquid X1 is placed by the droplet discharge method, and the placed wiring functional liquid X1 is dried and solidified, as shown in FIG. A conductor post 53 is formed on the wiring 51. The material of the conductor post 53 is Ag. The method for forming the conductor post 53 is not limited to the droplet discharge method, and a thin film forming method such as a vacuum deposition method or a sputtering method may be employed. And the thickness of the formed conductor post 53 is in the range of 3 to 5 μm.
(Second insulating layer forming step)

Next, in step S14 of FIG. 10, the insulating functional liquid X2 is arranged by the droplet discharge method, and the arranged insulating functional liquid X2 is dried and solidified, as shown in FIG. An insulating layer 54 is formed. As with the insulating layer 52, the insulating layer 54 is made of an acrylic resin insulating material. The formed insulating layer 54 has a thickness of about 15 μm.
(Second wiring formation process)

Next, in step S15 of FIG. 10, the wiring functional liquid X1 is arranged by the droplet discharge method, and the arranged wiring functional liquid X1 is dried and solidified, as shown in FIG. A wiring 55 is formed. The material of the wiring 55 is Ag. The method for forming the wiring 55 is not limited to the droplet discharge method, and a thin film forming method such as a vacuum evaporation method or a sputtering method may be employed. The formed wiring 55 has a thickness in the range of 3 to 5 μm.
(Plating layer forming process)

Next, in step S <b> 16 of FIG. 10, as shown in FIG. 9F, the plating layer 56 is laminated and the wiring pattern 60 is formed on the substrate P. The plating layer 56 includes a first plating layer 56a and a second plating layer 56b, and the first plating layer 56a is formed by an electroless plating method or an electrolytic plating method. The material of the first plating layer 56a is Ni, and the film thickness is in the range of 0.5 μm to 5 μm. For example, after applying a Pd catalyst on the wiring 55, the first plating layer 56a is formed. By doing in this way, Ni of the 1st plating layer 56a can be grown. A second plating layer 56b is formed on the first plating layer 56a by an electroless plating method or an electrolytic plating method. The material of the second plating layer 56b is Au, and the formed film thickness is in the range of 0.01 μm to 2 μm.
(Third insulating layer forming step)

Next, in step S17 of FIG. 10, the insulating functional liquid X2 is arranged by the droplet discharge method, and the arranged insulating functional liquid X2 is dried and solidified, as shown in FIG. An insulating layer 57 is formed. The insulating layer 57 is made of an acrylic resin insulating material, like the insulating layers 52 and 54. The thickness of the insulating layer 57 is about 5 μm. Then, the wiring board 50 can be formed. Since the insulating layer 57 is not formed on the terminal portion, the plating layer 56 of the terminal portion is exposed. The plating layer 56 other than the terminal portion is covered with an insulating layer 57.
(IC package bonding process)

  Finally, in step S18 of FIG. 10, as shown in FIG. 9H, the IC package 65 is joined to the terminal portion where the plating layer 56 of the wiring substrate 50 is exposed on the surface using the solder 63. And the circuit board 80 is made.

  Next, the liquid crystal display device 100 as the electro-optical device of the present invention using the wiring substrate 50 having the wiring pattern 60 will be described.

FIG. 11 is an exploded perspective view showing a liquid crystal display device 100 as an electronic apparatus.
The liquid crystal display device 100 of FIG. 11 includes a liquid crystal panel 73 and a driving circuit board (semiconductor device) 80. Further, an illumination device such as a backlight and other incidental structures are attached to the liquid crystal panel 73 as necessary. The liquid crystal panel 73 has a pair of substrates 131 and 132 whose peripheral edges are bonded to each other by a sealing material 133. For example, an STN (Super Twisted Nematic) type liquid crystal is formed in a gap formed between the substrates, a so-called cell gap. Is enclosed. The substrates 131 and 132 are made of a translucent material such as glass or synthetic resin. A polarizing plate 140 is attached to the outside of the substrates 131 and 132, and a retardation plate (not shown) is inserted between at least one of the substrates 131 and 132 and the polarizing plate 140. A display electrode 131 a is formed on the inner surface of one substrate 131, and a display electrode 132 a is formed on the inner surface of the other substrate 132. These display electrodes 131a and 132a are formed in stripes or letters, numbers, or other appropriate patterns. The display electrodes 131a and 132a are made of a light-transmitting conductive material such as ITO (Indium Tin Oxide).

  The liquid crystal panel 73 has a protruding portion 131T in which one substrate 131 extends from the other substrate 132, and a plurality of connection terminals 131b are formed in the protruding portion 131T. These connection terminals 131b are formed simultaneously with the formation of the display electrode 131a on the substrate 131, and are formed of, for example, ITO. These connection terminals 131b include those connected to the display electrode 131a and those connected to the display electrode 132a. Regarding the display electrode 132 a, the wiring from the connection terminal 131 b is connected to the display electrode 132 a on the other substrate 132 through a conductive material included in the seal material 133. Note that a large number of display electrodes 131a and 132a and connection terminals 131b are actually formed on the substrate 131 and the substrate 132 at extremely narrow intervals. In FIG. The intervals are schematically shown in an enlarged manner, and some of them are illustrated, and other portions are omitted. Further, the connection state between the connection terminal 131b and the display electrode 131a and the connection state between the connection terminal 131b and the display electrode 132a are also omitted in FIG.

  The circuit board 80 includes a film substrate P as a base material, a wiring pattern 60 formed on the film substrate P, an input terminal portion 75, an output terminal portion 76, a semiconductor IC mounting region (element mounting region) 81, and an IC package 65. I have. The film substrate P is formed of a polyimide resin having a thickness of 55 μm or less, particularly 25 μm or less, and has flexibility and insulation that can be bent at an arbitrary position. The circuit board 80 is a COF (Chip On Film) type flexible board in which an IC package 65 for driving liquid crystal is mounted on a semiconductor IC mounting region 81 of the film substrate P. The film substrate P does not necessarily need to be a polyimide resin, and may be a resin material that can be bent at an arbitrary position, an organic material, or the like. For example, polyethylene terephthalate, polyester, liquid crystal polymer, or the like may be used.

  The circuit board 80 is connected to an overhang 131 T of the substrate 131 of the liquid crystal panel 73 by an anisotropic conductive film (ACF) 135. The anisotropic conductive film 135 is formed of an adhesive resin and conductive particles mixed therein, and by pressure bonding, the circuit board 80 and the substrate 131 are fixed to each other by the adhesive resin. Each terminal of the output terminal portion 76 on the circuit board 80 side and the connection terminal 131b of the liquid crystal panel 73 are conductively connected. A control signal, a video signal, a power supply potential, and the like are supplied from the outside, and a driving signal (output signal) for driving a liquid crystal is generated in the IC package 65 and supplied to the liquid crystal panel 73.

  FIG. 12 is a diagram showing an example of a mobile phone 600 as an electronic apparatus including the liquid crystal display device 100 as the electro-optical device shown in FIG. In FIG. 12, a liquid crystal display unit 601 including the liquid crystal display device 100 is shown. Since the mobile phone 600 includes the liquid crystal display device 100 having the circuit board 80 (wiring board 50) that has good migration resistance and can be easily soldered, for example, the insulation is good and the quality is improved. The mobile phone 600 as an electronic device can be provided. In addition, since the wire bonding property and the flip chip bonding property are improved, the production efficiency is increased, so that the productivity of the liquid crystal display device 100 and the mobile phone 600 can be improved.

  In the second embodiment, the following effects can be obtained.

(5) In the wiring pattern 60, since the insulating layer 57 is formed so as to cover the upper surface of the wiring pattern 60 except for the terminal portion, the sheet-like curable product is formed on the wiring pattern 60 as in the prior art. Insulating properties can be obtained without stacking objects. In addition, since the insulating layer 57 is not formed on the terminal portion, it can be joined to the component.
(6) Since the wiring pattern 60 with improved migration resistance is provided, the wiring substrate 50 with improved insulation can be formed. If the insulation of the wiring board 50 is improved, the wiring 55 can be densified, so that the wiring board 50 that can be reduced in size and weight can be formed.
(7) Since the wiring board 50 with improved insulation is provided, the liquid crystal display device 100 as an electro-optical device with improved quality can be provided. In addition, since the wiring board 50 has a high density and can be reduced in size and weight, the liquid crystal display device 100 as an electro-optical device that can be reduced in size and weight can be provided.
(8) Since the liquid crystal display device 100 as an electro-optical device with improved quality is provided, a mobile phone 600 as a high-quality electronic device can be provided. In addition, since the liquid crystal display device 100 is an electro-optical device that can be reduced in size and weight, a mobile phone 600 as an electronic device that can be reduced in size and weight can be provided.

  The present invention has been described above with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and includes the following modifications and the scope in which the object of the present invention can be achieved. Thus, it can be set to any other specific structure and shape.

  (Modification 1) Although the flexible tape-like board | substrate P was employ | adopted when forming the wiring board 10 (50) in the above-mentioned embodiment, it is not restricted to this. For example, a rigid type such as a glass epoxy substrate or a ceramic substrate may be adopted. Even if it does in this way, the effect similar to the above-mentioned embodiment is acquired, and the wiring board 10 (50) which can improve a migration resistance is formed. If the migration resistance can be improved, the wiring substrate 10 (50) with improved insulation can be provided, so that an electro-optical device, electronic equipment, and the like with good insulation can be provided.

Schematic which shows the wiring pattern in 1st Embodiment. Schematic of a droplet discharge device. The figure for demonstrating the discharge principle of the liquid material by a piezo system. (A)-(d) is a figure which shows the manufacturing process of a wiring board. (E)-(g) is a figure which shows the manufacturing process of a wiring board. The schematic flowchart which shows the procedure of the manufacturing process of a wiring pattern. Schematic which shows the wiring pattern in 2nd Embodiment. (A)-(d) is a figure which shows the manufacturing process of a wiring board. (E)-(h) is a figure which shows the manufacturing process of a wiring board. The schematic flowchart which shows the procedure of the manufacturing process of a wiring pattern. 1 is an exploded perspective view of a liquid crystal display device as an electro-optical device. FIG. 11 illustrates a mobile phone as an electronic apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge head, 10 ... Wiring board, 11 ... Droplet, 13 ... Wiring, 14 ... Plating layer, 14a ... Ni film as 1st plating layer, 14b ... Au film as 2nd plating layer, DESCRIPTION OF SYMBOLS 16 ... Recessed part, 19 ... Gap, 30 ... Wiring pattern, 31 ... Droplet, 33 ... Insulating layer, 50 ... Wiring substrate, 51, 55 ... Wiring, 56 ... Plating layer, 56a ... Ni film as the first plating layer 56b ... Au film as second plating layer, 52, 54, 57 ... insulating layer, 59 ... gap, 60 ... wiring pattern, 100 ... liquid crystal display device as electro-optical device, 600 ... mobile phone as electronic device , P ... substrate, X1 ... functional fluid for wiring, X2 ... functional fluid for insulation.

Claims (10)

A method of forming a wiring pattern on a substrate using a droplet discharge method,
Disposing a first functional liquid containing the material of the wiring pattern on the substrate and solidifying the disposed first functional liquid to form a wiring;
Forming a plating layer so as to cover the wiring;
Disposing a second functional liquid containing an insulating material between the wirings of the wiring, and solidifying the disposed second functional liquid to form an insulating layer;
A wiring pattern forming method comprising: In the wiring pattern formation method of Claim 1,
In the step of forming the plating layer,
A wiring pattern forming method comprising: laminating a first plating layer and a second plating layer on the first plating layer to form the plating layer. In the wiring pattern formation method of Claim 1,
In the step of forming the plating layer,
A method for forming a wiring pattern, comprising forming the plating layer made of Au. In the wiring pattern formation method of Claim 2,
In the step of forming the plating layer,
A wiring pattern comprising: forming the plating layer by laminating the first plating layer made of Ni, the second plating layer made of Au, and the wiring made of Ag. Forming method. In the wiring pattern formation method as described in any one of Claims 1-4,
In the step of forming the insulating layer,
The wiring pattern forming method, wherein the insulating layer is formed so as to cover an upper surface of the wiring pattern at a place other than the terminal portion. A method of manufacturing a wiring board in which a wiring pattern is formed on a substrate using a droplet discharge method,
A method for manufacturing a wiring board, comprising forming the wiring pattern on the substrate using the wiring pattern forming method according to claim 1. A wiring board in which a wiring pattern is formed on a substrate using a droplet discharge method,
Wiring and
A plating layer formed to cover the wiring;
An insulating layer formed to cover the plating layer;
A wiring board comprising:   A wiring board formed using the method for manufacturing a wiring board according to claim 6.   An electro-optical device comprising the wiring board according to claim 7. An electronic apparatus comprising the electro-optical device according to claim 9.

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