JP2008012384A - Method of forming fine line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming fine lines improved in linearity by suppressing the spreading of wetting without requiring a preceding process for forming an interface such as a liquid repellent area along the desired lines and an additional process such as a heating process. <P>SOLUTION: The fine lines are formed by discharging a dispersion liquid containing metal fine particles to a predetermined position on a substrate 1 as droplets 2. The method of forming the fine line comprises: a first process of forming a fine line 4 having such a shape that the cross-section shape has a recessed part on the central part by discharging the droplets onto a substrate; and a second process of forming a fine line 5 by discharging the droplets into the recessed part of the fine line formed on the first process. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for forming a fine line used for manufacturing a device having a fine line such as a plasma display panel.

  Plasma display panels are broadly classified into AC types and DC types as driving methods, and there are two types of discharge types: surface discharge type and counter discharge type. At present, the mainstream of plasma display panels is a surface discharge type having a three-electrode structure because of high definition, large screen, and ease of manufacture (see, for example, Patent Document 1).

  The structure of a surface discharge type plasma display panel (hereinafter also referred to as PDP) is shown in FIG. This PDP is configured by disposing a glass front substrate 1 and a back substrate 2 so as to form a discharge space therebetween.

  On the front substrate 1, a plurality of scanning electrodes 3 and sustaining electrodes 4 constituting display electrodes are formed in parallel with each other. A dielectric layer 5 is formed so as to cover the scan electrode 3 and the sustain electrode 4, and a protective layer 6 is formed on the dielectric layer 5. Scan electrode 3 and sustain electrode 4 are each composed of transparent electrodes 3a and 4a and bus electrodes 3b and 4b made of a metal material. The front plate unit 7 is configured by providing the above elements on the front substrate 1.

  A plurality of data electrodes 9 covered with an insulator layer 8 are provided on the back substrate 2, and a grid-like partition wall 10 is provided on the insulator layer 8. A phosphor layer 11 is provided on the surface of the insulator layer 8 and on the side surfaces of the partition walls 10. The back plate unit 12 is configured by providing the above elements on the back substrate 2.

  The front plate unit 7 and the back plate unit 12 having the above-described configuration are disposed to face each other so that the scan electrode 3, the sustain electrode 4, and the data electrode 9 intersect each other, and a discharge gas formed therebetween has a discharge gas. For example, a mixed gas of neon and xenon is enclosed. For the phosphor layer 11, phosphors that emit red, green, and blue light by discharge are used, and the phosphors are excited by vacuum ultraviolet light having a short wavelength generated by the discharge, respectively from the red, green, and blue discharge cells. Color display is performed by emitting visible light of red, green, and blue.

  By the way, in this PDP, as a method for forming electrodes or the like, a method for forming a fine line on a substrate by discharging a dispersion liquid as droplets has been studied.

  As a typical method for forming fine lines on a substrate, a photolithography method has been conventionally used. In this method, after a film pattern is formed on a substrate using a screen printing method or the like, a desired fine line is obtained using a photolithography method. For this reason, there are disadvantages such as complicated processes and equipment and low material utilization.

Therefore, for example, as in Patent Document 1, a method of forming a fine line by, for example, an ink jet method has been proposed.
JP 2003-243328 A

  Conventionally, when forming fine lines by an ink jet method or the like, it has been necessary to reduce the amount of one discharge in order to suppress wetting and spreading. As a result, overcoating is necessary until a desired film thickness is obtained.

  In the method disclosed in Patent Document 1, the dispersion or solution is discharged so that the interface of the dispersion in which the dispersoid is dispersed or the solution in which the solute is dissolved follows a predetermined pattern. Thereafter, a line is formed by collecting the dispersoid or solute at the interface of the dispersion or solution. Therefore, other processes such as a pre-process for forming an interface such as a liquid repellent region along a desired line and a process such as heating are required, and the process becomes complicated.

  An object of the present invention is to achieve a desired line width and linearity efficiently while suppressing wetting and spreading in such a fine line forming method.

  In order to achieve the above object, the present invention provides a method for forming a fine line by discharging a dispersion liquid containing ultrafine metal particles as droplets to a predetermined position on a substrate. A first step of forming a fine line having a cross-sectional shape having a recess in the central portion by discharging a droplet, and discharging a droplet into the recess of the fine line formed in the first step to further form a fine line And a second step.

  According to the present invention, by ejecting droplets on a substrate at a predetermined ejection speed or higher, a collision line is used to form a fine line whose cross-sectional shape has a middle recess. Next, since the amount of liquid droplets to be ejected into the recesses is concave, even if the amount is larger than the conventional overcoating droplet amount, wetting spread can be suppressed and linearity can be improved. In addition, since the amount of liquid droplets is larger than before, tact-up is naturally possible.

  Furthermore, in the method of the present invention, there is no need for any other process such as a pre-process for forming an interface such as a liquid repellent region along a desired line or a process such as heating, and only a process for discharging droplets is required. A line can be formed.

  In the first step of the method for forming a fine line of the present invention having the above structure, in the first step, the ultrafine metal particles have a particle size of 100 [nm] or less, and the dispersion has a viscosity of 1 to 20 [mPa · s], The surface tension is 25 to 80 [mN / m], the solid content concentration is 5 to 40 [w%], the droplet discharge speed is √ (4.83 / m) [m / s] (m = 1 drop Weight [ng]) or more.

  In the second step, the ultrafine metal particles have a particle size of 100 [nm] or less, the dispersion has a viscosity of 1 to 20 [mPa · s] or less, and a surface tension of 25 to 80 [mN / m. It is preferable that the solid content concentration is 5 to 40 [w%] and the droplet discharge speed is less than √ (4.83 / m) [m / s] (m = 1 weight of the droplet [ng]). .

  Further, the dispersion discharged in the first step and the dispersion discharged in the second step can be made the same.

  Further, the dispersion liquid discharged in the first step and the dispersion liquid discharged in the second step can be made different. For example, in the second step of discharging into the recess, a dispersion different from the first step, which is excellent in conductivity, is used to reduce the amount of material used. As described above, the fine lines can be formed accurately and efficiently by properly using the dispersion liquid used in the first step and the second step.

  Further, after the second step, the same step as the second step may be repeated 1 to 20 times.

  Moreover, it is preferable that the contact angle of the said board | substrate and the said droplet of the said 1st process is 45-90 [deg].

  Hereinafter, a fine line forming method according to an embodiment of the present invention will be described with reference to FIGS. 1A and 2A are front views showing steps of a fine line forming method, and FIG. 1B is a cross-sectional view of FIG.

<First step>
First, as shown in FIG. 1A, a droplet material is ejected from the ejection means 3 as a droplet 2 to a predetermined position on the substrate 1 to form a fine line 4. By making the discharge speed of the droplet 2 at this time equal to or higher than the value represented by the following (Equation 1), the cross-sectional shape as shown in FIG. Become. In (Formula 1), m = 1 weight of the drop [ng].

    √ (4.83 / m) [m / s] (Formula 1)

  In this first step, the contact angle between the droplet 2 and the substrate 1 is preferably 45 to 90 [deg]. In the case of forming the conductive film wiring, a dispersion liquid having a contact angle of 70 to 90 [deg] is more preferably used in order to narrow the line width. In addition, as a method of discharging the droplet material as the droplet 2, an inkjet method can be used.

<Second step>
Next, as shown in FIG. 2A, the droplet 2 is discharged into the concave portion 4 of the fine line formed in the first step. By setting the discharge speed of the droplet 2 at this time to be less than the value represented by the above (Equation 1), it is possible to discharge without wetting and spreading as shown in FIG.

  As a method for ejecting the droplet material as the droplet 2, an inkjet method can be used. Furthermore, since the amount of droplets at this time is recessed in the center of the previously formed fine line, even if it is larger than the amount of droplets of conventional overcoat, wetting spread can be suppressed and linearity can be improved. it can. Moreover, since the amount of liquid droplets is larger than before, it is possible to improve the tact time. If necessary, the second step can be repeated 1 to 20 times thereafter.

  For example, when forming conductive film wiring as an example, in the second step of discharging into the recesses, it is possible to use a dispersion different from the first step, which has excellent conductivity in order to reduce the amount of material used. it can. In this way, by properly using the dispersion liquid used in the first step and the second step, the formation of fine lines can be realized with high accuracy and efficiency. Of course, the same dispersion can be used in the first step and the second step.

  Regarding the characteristics of the dispersion liquid, which is a droplet material used in the present invention, it is desirable to satisfy the following conditions in order to realize the supply stability of the dispersion liquid and the flight stability of the dispersion liquid. That is, the viscosity is 1 to 20 [mPa · s] or less, preferably 1 to 10 [mPa · s] at a temperature (5 to 60 degrees) and humidity (10 to 70%) in a normal operation time, and its surface The tension is 25 to 80 [mN / m], preferably 35 to 50 [mN / m], and the solid content concentration is 5 to 40 [w%], preferably 10 to 25 [w%].

  In a dispersion satisfying this characteristic, the cross-sectional shape as shown in FIG. 1 becomes a shape having a concave portion in the center portion due to the collision energy by setting the discharge speed to be equal to or higher than the value represented by the above (Equation 1). .

  Specific examples of the solvent that can be used in the present invention include water, alcohols such as ethanol, methanol, butanol, and propanol, n-octane, n-heptane, toluene, decane, xylene, durene, Hydrocarbon solvents such as cymene, indene, dipentene, decahydronaphthalene, tetrahydronaphthalene, cyclohexylbenzene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, 1, Ether solvents such as 2-dimethoxyethane, bis (2-methoxyethyl) ether, p-dioxane, propylene carbonate, γ Butyrolactone, N- methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, there is a polar solvent such as cyclohexanone.

  FIG. 3 is a perspective view showing a schematic configuration of a forming apparatus used in the fine line forming method according to the embodiment of the present invention. The fine line forming apparatus includes a coating mechanism 6, a substrate mounting base 8, a driving mechanism 7, and a control device 9. The coating mechanism 6 includes an inkjet type coating apparatus that discharges the dispersion liquid as droplets to a predetermined position on the substrate 1. The substrate mounting base 8 includes a mechanism for installing the substrate 1 on which the liquid is applied by the coating device. The drive mechanism 7 includes a mechanism for moving the substrate mounting base 8 in the X direction and the Y direction. The coating mechanism 6 is fixed, and fine lines are formed by moving the substrate 1. The control device 9 controls the synchronization of the movement in the X direction and the Y direction by the drive mechanism 7 and the ejection of the droplets from the coating mechanism 6.

  Hereinafter, the present invention will be described with reference to specific examples. The present invention is not limited to the following examples.

<Example 1>
By changing the discharge speed of the droplet, the change in the amount of the middle recess when the droplet was discharged was verified. A dispersion containing silver powder on a glass substrate on which ITO is already formed (Nippon Paint Co., Ltd. Finesphere SVW102, silver particle maximum particle size 76.3 [nm], temperature 25 degrees, humidity 50% The viscosity is 8 [mPa · s], the surface tension is 40 [mN / m], and the solid content concentration is 30 [w%].) The apparatus of FIG. The ink was discharged using IJK-100T manufactured by Jet Co.

  The specific gravity of the dispersion is 1.4, the contact angle between the substrate and the dispersion is 53 [deg], the distance from the nozzle tip to the substrate is 1 [mm], and the discharge frequency of the dispersion is 10 [kHz]. did. Further, the weight of one droplet of the discharged dispersion was 19.6 [ng], 53.6 [ng], and 120.7 [ng]. The relationship is shown in FIG. When the weight of one drop is 19.6 [ng] (FIG. 4 (a)), the weight of one drop is 19 for m of √ (4.83 / m) (equation 1) of the above-described discharge speed. Substituting .6 [ng] yields √ (4.83 / 19.6) = 0.5 [m / s].

  Therefore, in the case of this dispersion liquid, if the discharge speed is 0.5 [m / s] or more, the discharged dispersion liquid becomes a fine line with a cross-section in the middle recessed portion by collision energy as shown in FIG. Moreover, if it is less than 0.5 [m / s], a cross-sectional shape will not become a shape which has a recessed part in the center part. As shown in FIG. 4A, in the verification result, a middle recess was generated at 0.5 [m / s] or more.

  Similarly, when the weight of one drop is 53.7 [ng] (FIG. 4B), the weight of one drop is 53.7 for m of the discharge speed (Formula 1), √ (4.83 / m). Substituting [ng] yields √ (4.83 / 53.7) = 0.3 [m / s]. Therefore, in the case of this dispersion liquid, if the discharge speed is 0.3 [m / s] or more, the discharged dispersion liquid becomes a fine line having a cross section in the middle concave portion due to the collision energy as shown in FIG. Moreover, if it is less than 0.3 [m / s], a cross-sectional shape will not become a shape which has a recessed part in the center part. As shown in FIG. 4B, in the verification result, a middle recess was generated at 0.3 [m / s] or more.

  Similarly, when the weight of one drop is 120.8 [ng], substituting the weight of one drop of 120.8 [ng] for m of (Expression 1) and √ (4.83 / m) of the discharge speed, √ (4.83 / 120.8) = 0.2 [m / s]. Therefore, in the case of this dispersion liquid, if the discharge speed is 0.2 [m / s] or more, the discharged dispersion liquid has a fine line with a cross-sectional shape having a concave portion in the central part due to collision energy as shown in FIG. become. Moreover, if it is less than 0.2 [m / s], a cross-sectional shape will not become a shape which has a recessed part in the center part. As shown in FIG. 4C, in the verification result, the cross-sectional shape is a shape having a recess at the center at 0.2 [m / s] or more.

<Example 2>
For the PDP 42 type panel, the discharge electrode of the front plate unit and the address electrode of the back plate unit were formed, and a PDP panel was prepared and evaluated. The electrode formation process and panel creation process will be described below.

  First, in order to form the discharge electrode of the front plate unit, a dispersion similar to that in Example 1 is discharged onto a glass substrate on which ITO has already been formed using the same apparatus as in Example 1, Produced. The specific gravity of the dispersion is 1.4, the contact angle between the substrate and the dispersion is 53 [deg], the distance from the nozzle tip to the substrate is 1 [mm], and the discharge frequency of the dispersion is 10 [kHz]. did. Further, the weight of one droplet of the discharged dispersion was set to 19.6 [ng].

  Here, substituting 19.6 [ng] for the weight of one drop into m of the above-described discharge speed (Equation 1), that is, √ (4.83 / m), √ (4.83 / 19.6) = 0.5 [m / s].

  Therefore, in the case of this dispersion liquid, if the discharge speed is 0.5 [m / s] or more, the discharged dispersion liquid has a cross-sectional shape having a concave portion in the center portion due to collision energy as shown in FIG. . Moreover, if it is less than 0.5 [m / s], a cross section will not become a middle recessed part.

  In the first step, droplets were discharged onto the substrate at a discharge speed of 2.5 [m / s]. Since the droplet velocity was 0.5 [m / s] or more, the discharged dispersion became a fine line having a line width of 50 [μm] with a cross-sectional shape having a recess at the center.

  In the second step, the liquid droplets were discharged into the concave portions of the fine lines formed in the first step at a discharge speed of 0.3 [m / s]. Since the discharge speed is less than 0.5 [m / s], the discharged dispersion liquid does not spread as shown in FIG. 2 and forms a fine line with a line width of 50 [μm] that does not have a defective portion such as disconnection. I was able to. After this electrode was dried, a dielectric having a thickness of about 40 μm was applied to the entire surface by screen printing and baked at a temperature of 600 ° C. for 30 minutes.

  With respect to the address electrodes of the back plate unit, a fine line with a line width of 50 [μm] having no defective parts such as disconnection could be formed on the glass substrate by the same material and configuration of the front plate unit. . After this electrode was dried, a dielectric having a thickness of about 40 μm was applied to the entire surface by screen printing and baked at a temperature of 600 ° C. for 30 minutes.

  Then, the front plate unit and the back plate unit on which the electrodes were formed as described above were sealed, exhausted, and filled with gas, and then subjected to an aging treatment to assemble as a PDP panel. As a result of conducting a lighting test for 1000 hours on this panel, it was confirmed that the durability of the electrode was sufficient. In addition, this panel showed no difference in image even when compared with a panel produced by a conventional method.

<Example 3>
Forty lines having a line width of 50 μm and a line interval of 50 μm were drawn in parallel with the same material and configuration as in Example 2 to create a conductive circuit line. And as a result of evaluating film thickness, linearity, surface resistance, and resistivity, no difference was recognized even when compared with the conductive circuit manufactured by the method of the prior art.

  The fine line forming method of the present invention can suppress wetting and spread and improve linearity even when a larger amount of liquid droplets is ejected than before. Furthermore, these means do not require any other processes such as a pre-process for forming an interface such as a liquid repellent region along a desired line, or a process such as heating. Can be formed. Therefore, it can be used for manufacturing display panels and printed circuit boards.

The 1st process of the formation method of the fine line in one embodiment of the present invention is shown, (a) is a front view and (b) is a sectional view. The 2nd process of the formation method is shown, (a) is a front view, (b) is a sectional view. The perspective view which shows the structure of the fine line formation apparatus used for the formation method of the fine line of this invention The figure which shows the relationship between the droplet speed and film thickness when forming the fine line of this invention An exploded perspective view showing a plasma display panel

Explanation of symbols

1 Substrate 2 Droplet 3 Discharge means 4, 5 Fine line

Claims (7)

In a forming method of forming a fine line by discharging a dispersion containing ultrafine metal particles as droplets to a predetermined position on a substrate,
A first step of forming a fine line having a cross-sectional shape having a recess in the center by discharging a droplet onto the substrate; and a droplet is discharged into the recess of the fine line formed in the first step. And a second step of forming a fine line.   In the first step, the ultrafine metal particles have a particle size of 100 nm or less, the dispersion has a viscosity of 1 to 20 [mPa · s] or less, a surface tension of 25 to 80 [mN / m], The solid content concentration is 5 to 40 [w%], and the discharge speed of the droplet is √ (4.83 / m) [m / s] (m = 1 weight of the droplet [ng]) or more. Method for forming fine lines.   In the second step, the ultrafine metal particles have a particle size of 100 [nm] or less, the dispersion has a viscosity of 1 to 20 [mPa · s] or less, and a surface tension of 25 to 80 [mN / m], The solid content concentration is 5 to 40 [w%], and the discharge speed of the droplet is less than √ (4.83 / m) [m / s] (m = 1 weight of the droplet [ng]). Method for forming fine lines.   The method for forming a fine line according to claim 1, wherein the dispersion liquid discharged in the first step and the dispersion liquid discharged in the second step are the same.   The fine line forming method according to claim 1, wherein the dispersion discharged in the first step and the dispersion discharged in the second step are different.   The method for forming a fine line according to claim 1, wherein the same step as the second step is repeated 1 to 20 times after the second step.   2. The fine line forming method according to claim 1, wherein a contact angle between the substrate and the droplet in the first step is 45 to 90 [deg].

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