JP2000068629A - Repair of electrode discontinuity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of repairing a discontinued electrode, which coats a paste on a defect part in the electrode and repair the discontinued electrode. SOLUTION: This discontinuity repairing method is a method wherein when a conductive paste is applied on a defect part in an electrode and a continuity of the electrode is restored using the conductive paste in a substrate formed with the electrode using a conductive paste, the restoration of the continuity is achieved by satisfying the relation of 0.01×α<=A<=2×α between the mean grain dismeter A of conductive powder being contained in the conductive paste for resotration and the mean grain diameter αof conductive powder being contained in the conductive paste used for the formation of the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a disconnection of an electrode.

[0002]

2. Description of the Related Art In a substrate on which electrodes are formed by using a conductive paste, dust may be mixed in the formation process,
If the electrode is scratched, a disconnection defect occurs in which the electrode is cut in the middle. As a method of repairing a disconnection defect,
For example, as described in JP-A-9-307217, a method of applying a repairing conductive paste to a disconnection defect is known. However, when the repairing conductive paste is applied to the disconnection defect, there are problems such as poor application and cracking when heat treatment is performed after application.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for repairing an electrode disconnection which can easily, reliably and efficiently repair a disconnection defect of an electrode formed on a substrate by using a conductive paste. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for repairing a disconnection defect portion of an electrode using a repair paste on a substrate on which an electrode is formed using a conductive paste.
The average particle diameter A of the conductive powder contained in the repairing paste satisfies the following relationship with the average particle diameter α of the conductive powder contained in the conductive paste used when forming the electrode. This is achieved by a method for repairing disconnection of an electrode characterized by the following.

[0005] 0.01 × α ≦ A ≦ 2 × α

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive paste of the present invention contains a conductive powder and an organic component. The inventors have found that the problems of the conventional disconnection repair method as described above are that the average particle diameter of the conductive powder contained in the conductive paste used for forming the electrode and the conductive powder contained in the repairing conductive paste are different. It has been found that the problem can be solved by setting the average particle diameter relationship within a specific range.

The average particle size A of the conductive powder contained in the repairing conductive paste according to the present invention is smaller than the average particle size α of the conductive powder contained in the conductive paste used for forming the electrode. It is necessary to satisfy the relationship

If A is smaller than 0.01 × α, it becomes difficult to obtain a paste in which the particles are aggregated and the particles are uniformly dispersed. . As a result, unevenness is generated in the paste, and a step is likely to occur between the end of the electrode at the disconnection location and the applied location. Further, when the step is large, stress is concentrated on the step, and cracks and peeling occur. When A is larger than 2 × α, when the coating is applied to the disconnection defect, the adhesiveness of the portion in contact with the formed electrode is poor, and it is easy to peel off. Further, when the electrode is thin, a step is generated between the end of the electrode at the disconnection point and the applied point, and when a film such as a dielectric is laminated, stress concentrates on the step and cracks and peeling occur.

The repairing conductive paste in the present invention preferably uses the same conductive paste as the conductive paste used for forming the electrodes. The same conductive paste as referred to herein means that not only the average particle size of the conductive powder is within the above range, but also the main component of the conductive powder and the organic component contained in the repairing conductive paste is an electrode. Is the same as that of the conductive paste used for forming the conductive paste. Of course, the conductive paste used for forming the electrodes may be used as it is as the repairing conductive paste.
By using the same conductive paste, the adhesion between the electrode and the repairing conductive paste is further increased, and cracks and peeling are less likely to occur.

The conductive powder may be in the form of particles (particles), polyhedrons, or spheres, but is preferably monodisperse particles, having no aggregation and being spherical. In this case, the spherical shape preferably has a sphericity of 90% by number or more. For the measurement of the sphericity, the powder was photographed with an optical microscope at a magnification of 300 times, and countable particles were counted, and the ratio of spherical particles was represented.

The conductive powder contained in the repairing conductive paste of the present invention is made of Ag, Au, Pd, Ni and Pt.
Preferably, a low-resistance conductor powder that can be baked on a glass substrate at a temperature of 600 ° C. or less is used. These can be used alone or as a mixed powder. For example, Ag (80
-98) -Pd (20-2), Ag (90-98) -P
d (10-2) -Pt (2-10), Ag (85-9)
8) A ternary or binary mixed noble metal powder such as -Pt (15-2) (where the parentheses indicate weight%) are used.

The repairing conductive paste in the present invention is preferably a photosensitive conductive paste. This is because after application of the paste to the disconnection point, the paste is solidified by irradiating light, and handling in a subsequent step becomes easy. In order to make the repairing conductive paste photosensitive, the paste may contain a photosensitive compound.

With respect to the photosensitive conductive paste used in the repairing conductive paste of the present invention, the content of the photosensitive compound is preferably at least 10% by weight of the organic component from the viewpoint of sensitivity to light. More preferably, it is at least 30% by weight.

As the photosensitive compound, there are a photo-insolubilizing type and a photo-solubilizing type.
(1) those containing a functional monomer, oligomer or polymer having at least one unsaturated group in the molecule;
(2) those containing photosensitive compounds such as aromatic diazo compounds, aromatic azide compounds, and organic halogen compounds;
(3) So-called diazo resins, such as condensates of diazo-based amines and formaldehyde, and the like.

Examples of the photo-soluble type include (4) a complex of a diazo compound with an inorganic salt or an organic acid, a compound containing a quinonediazo compound, and (5) a quinonediazo compound combined with an appropriate polymer binder. For example, naphthoquinone 1,2-diazide of phenol, novolak resin
5-sulfonic acid ester, and the like.

In the present invention, all of the above can be used, but the above (1) is preferred in terms of ease of handling and quality design.

Specific examples of the photosensitive monomer having a functional group in the molecule include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, sec-butyl acrylate, isobutyl Acrylate, tert-butyl acrylate, n-pentyl acrylate, allyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, Glycidyl acrylate, heptadecafluorodecyl acrylate, 2-hydroxyethyl acrylate Relate, isobonyl acrylate, 2-hydroxypropyl acrylate, isodecyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, Trifluoroethyl acrylate, allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, diglycol Pentaerythritol hex Acrylate,
Dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropanetetraacrylate,
Glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, trimethylolpropane triacrylate, acrylamide, aminoethyl acrylate and intramolecular acrylates of the above compounds Are partially or entirely changed to methacrylate, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-2-pyrrolidone, and the like.

Also, phenyl acrylate, phenoxyethyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct, and diphenol of bisphenol A-propylene oxide adduct Acrylate, 1
-Naphthyl acrylate, 2-naphthyl acrylate,
Acrylates such as thiophenol acrylate and benzyl mercaptan acrylate, styrenes such as styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, chloromethylstyrene, hydroxymethylstyrene, and fragrances thereof There can be used those obtained by substituting part or all of the hydrogen atoms in the ring with chlorine, bromine atom, iodine or fluorine, and those obtained by substituting part or all of the acrylate in the molecule of the above compound with methacrylate. In the present invention, one or more of these can be used.

On the other hand, as an example of an oligomer or polymer having a functional group in the molecule, a functional group is added to a side chain or a molecular terminal of an oligomer or polymer obtained by polymerizing at least one of the aforementioned monomers. Can be used. By containing an alkyl acrylate or an alkyl methacrylate, more preferably by containing methyl methacrylate, a polymer having good thermal decomposability can be obtained.

Preferred functional groups are those having an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, an acryl group, and a methacryl group.

A method for adding such a functional group to an oligomer or a polymer is to use an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, an acrylic acid, or a mercapto group, an amino group, a hydroxyl group or a carboxyl group in the polymer. There is a method in which chloride, methacrylic chloride or allyl chloride is added to make an addition reaction.

Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, and glycidyl ether isocrotonic acid. .

Examples of the ethylenically unsaturated compound having an isocyanate group include (meth) acryloyl isocyanate and (meth) acryloylethyl isocyanate.

The ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride or allyl chloride is used in an amount of 0.05 to 0.05 to the mercapto group, amino group, hydroxyl group and carboxyl group in the polymer. It is preferable to add one molar equivalent.

As a binder, non-photosensitive to polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, acrylate-methacrylate copolymer, α-methylstyrene polymer, butyl methacrylate resin, etc. A hydrophilic polymer may be added.

In the present invention, it is preferable to add a glass frit to the repairing conductive paste. The glass frit has the effect of improving the adhesion to the glass substrate when the conductive powder is baked on the glass substrate, and also acts as a sintering aid for sintering the conductive powder and has the effect of lowering the conductor resistance. Because there is. The glass transition temperature (Tg) and softening point (Ts) of the glass frit were 4
The temperature is preferably from 00 to 500 ° C and from 450 to 550 ° C. Preferably, Tg and Ts are each 440 to 50
0 ° C, 460-530 ° C. When Tg and Ts are less than 400 ° C. and 450 ° C., respectively, sintering of the glass starts before the photosensitive organic compound such as a polymer or a monomer evaporates, the debinding of the organic compound does not work well, and the carbon becomes residual carbon after firing. It is not preferable because it causes peeling of the repaired portion and a dense and low-resistance conductor film cannot be obtained.
If Tg and Ts exceed 500 ° C. and 550 ° C., respectively, the glass frit cannot obtain a sufficient adhesive strength or a dense film between the conductive film and the glass substrate when baked at a temperature of 600 ° C. or less.

The coefficient of thermal expansion α ₅₀ to _{400 at 50} to ₄₀₀ ° C. of the glass frit is preferably 75 to 90 × 10 ⁻⁷ / ° K. If the coefficient of thermal expansion is not in this range, the conductor film baked on the glass substrate will be peeled off during cooling due to the difference in the coefficient of thermal expansion between the substrate and the glass frit.

In the present invention, the composition of the glass frit is preferably such that Bi ₂ O ₃ is blended in the range of 30 to 95% by weight. When the amount is less than 30% by weight, it is not sufficient to control the glass transition point and the softening point when baked on a substrate, and has little effect in increasing the adhesive strength of the conductive film to the substrate. If it exceeds 95% by weight, the softening point of the glass frit becomes too low, and the glass frit is melted before the binder in the paste evaporates. For this reason, the binder removal property of the paste is deteriorated, the sinterability of the conductor film is reduced, and the adhesive strength with the substrate is reduced.

Furthermore, the glass frit contains a composition of Bi ₂ O ₃ 30~87 wt% SiO ₂ 5 to 30 wt% B ₂ O ₃ having 6 to 20 wt% ZnO 2 to 20% by weight in terms of oxide title Is preferred. Within this range, 5
A glass frit capable of firmly baking a conductive film on a glass substrate at 50 to 600 ° C. is obtained.

In particular, when the glass frit composition of the present invention is used, PbO which is liable to cause a gelling reaction of a photosensitive organic component is obtained.
It is possible to obtain a preferable glass frit without using any of the above, avoid problems such as an increase in paste viscosity due to a gelation reaction, and obtain a stable conductive paste for repair.

The content of SiO ₂ is preferably in the range of 5 to 30% by weight, and if it is less than 5% by weight, the adhesive strength when baked on a substrate and the stability of the glass frit are reduced. On the other hand, if it exceeds 30% by weight, the heat-resistant temperature increases, and it becomes difficult to bake on a glass substrate at 600 ° C or lower.

It is preferable that B ₂ O ₃ is blended in the range of 6 to 20% by weight. B ₂ O ₃ has a baking temperature of 550 so as not to impair the electrical, mechanical and thermal properties of the repairing conductive paste, such as electrical insulation, adhesive strength, and coefficient of thermal expansion.
It is blended to control the temperature in the range of -600 ° C. If it is less than 6% by weight, the adhesion strength will be reduced, and if it exceeds 20% by weight, the stability of the glass frit will be reduced.

It is preferable that ZnO is blended in the range of 2 to 20% by weight. When the content is less than 2% by weight, the effect of controlling the baking temperature is small when the repairing conductive paste is baked on a glass substrate. If it exceeds 20% by weight, the heat-resistant temperature of the glass will be too low, and it will be difficult to bake it on a glass substrate.

The glass frit powder includes alkali metals such as Na ₂ O, Li ₂ O, K ₂ O, BaO, and CaO, which cause the glass substrate to turn yellow by reacting with the silver powder and deteriorate the discharge characteristics of plasma. Preferably, it does not substantially contain an oxide of an earth metal. Substantially not included
It is at most 0.5% by weight, preferably at most 0.1% by weight.

In the glass frit, Al ₂ O ₃ , Ba
The thermal expansion coefficient, glass transition point, and softening point can be controlled by incorporating O, TiO ₂ , ZrO _2, etc., but the amount is preferably less than 10% by weight.

The content of glass frit in the photosensitive conductive paste is preferably 1 to 4% by weight. More preferably, it is 1 to 3.5% by weight. Since the glass frit is electrically insulating, its content exceeding 4% by weight is not preferable because the electrical resistance increases. Further, when the glass frit increases, in a thin film having a thickness of 10 μm or less, film peeling occurs due to a difference in thermal expansion coefficient between the conductive powder and the glass frit. If it is less than 1% by weight, it is difficult to obtain a strong adhesive strength between the film and the glass substrate.

In the repairing conductive paste used in the present invention, a photopolymerization initiator, a sensitizer, a sensitizing aid,
Polymerization inhibitor, plasticizer, thickener, organic solvent, antioxidant,
Additive components such as dispersants and suspending agents can be added.

In the present invention, when a metal and / or metal oxide serving as a sintering aid is added in addition to the glass frit, abnormal grain growth can be avoided during sintering of the conductive powder, or sintering can be delayed. This has the effect and, as a result, increases the adhesive strength between the conductor film and the glass substrate, which is preferable. Such oxide powders as Cu, Cr, Mo,
Metals and / or metal oxides such as Al or Ni can be used. Of these, metal oxides act as electrical insulators, so the smaller the amount of additive, the better.
Not more than 3% by weight. If it exceeds 3% by weight, the electric resistance of the conductor film increases, which is not good. It is also preferable to use a metal oxide and a metal together.

To adjust the viscosity of the solution, an organic solvent may be added to the repairing conductive paste used in the present invention. Examples of the organic solvent used at this time include methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, and the like. . These organic solvents are used alone or in combination of two or more.

The preferred composition of the photosensitive conductive paste is preferably selected in the following range. (A) conductive powder; 84 to 94% by weight based on the sum of (a), (b) and (c) (b) photosensitive compound; based on the sum of (a), (b) and (c) (C) glass frit; 1 to 4% by weight based on the sum of (a), (b) and (c); (d) photopolymerization initiator; 5 to 20% by weight relative to (b) % More preferably, (a), (b), (c)
Are 86 to 92% by weight, 11 to 7% by weight, and 1 to 3% by weight, respectively. This range is preferred because the conductor film after firing has a low resistance and a high bonding strength.

Further, if necessary, a sensitizer, a photopolymerization accelerator, a plasticizer, a dispersant, a stabilizer, a thixotropic agent, and a precipitation inhibitor are added to form a slurry of the mixture. The slurry adjusted to have a predetermined composition is uniformly mixed with a stirrer such as a homogenizer, and then uniformly dispersed with a three-roller or kneader to produce a paste.

The paste has a viscosity of a conductive powder, an organic solvent,
The composition and type of the glass frit, the addition ratio of the plasticizer, the thixotropic agent, the suspending agent, the organic leveling agent and the like are appropriately adjusted, and the range is 5,000 to 150,000 cps (centipoise) at 3 rpm. is there.

The electrode is repaired by applying a repairing conductive paste to the disconnection defect portion of the electrode. There is no particular limitation on the method of application. (A) Attaching the conductive paste for repair to the tip of the needle (B) Using a syringe, dispenser, etc., apply a certain amount of paste from the container containing the conductive paste for repair to the tip of the nozzle. The feeding method is preferable because the paste can be easily and reliably applied to the disconnection defect portion.

Next, the coating film is fired in the air. Although the entire substrate may be placed in a firing furnace, it is easier and preferable to locally heat the paste application section. As the heating method,
Hot air may be blown with a blower or infrared rays may be applied. Alternatively, the light may be focused on the paste application section using a laser and heated.

[0045]

The present invention will be described in detail with reference to the following examples. The disconnection defect of the electrode was repaired and evaluated by the following materials A to H and a to d shown below. In the following examples, all concentrations are expressed by weight% unless otherwise specified.

Examples 1 to 7 The particle size distribution (average particle size, specific surface area, etc.) of the conductive powder and the glass frit was determined by the method of Lead & Northrup.
Microtrac Particle Size Analyzer (9320-HRA)
It measured using.

A. Conductive powder Ag powder; monodispersed granules were added in proportions (parts by weight) shown in Table 1.

B. Photosensitive polymer (hereinafter abbreviated as polymer) A copolymer composed of 40 mol% of methacrylic acid (MAA), 30 mol% of methyl methacrylate (MMA) and 30 mol% of styrene (St) has a content of 0.1% based on MAA. A polymer obtained by addition reaction of 4 equivalents of glycidyl methacrylate (GMA) was added at a ratio (parts by weight) shown in Table 1.

C. Photosensitive monomer (hereinafter abbreviated as monomer) Trimethylolpropane triacrylate was added in the ratio (parts by weight) shown in Table 1.

D. Glass frit component (% by weight) bismuth oxide (46.2), silicon dioxide (27.1), boron oxide (11.8), zinc oxide (2.
6), sodium oxide (4.7), aluminum oxide (2.8), zirconium oxide (4.8), average particle diameter 0.9 μm, 90% particle diameter 1.7 μm, top size 3.3 μm, glass transition Point: 461 ° C., softening point: 513
° C., the thermal expansion coefficient of _{50~400 ℃ (α 50 ~ 400)} ; 82
A glass frit of × 10 ^-7 / ゜ K was added in the ratio (parts by weight) shown in Table 1.

E. Solvent γ-butyrolactone F. Photopolymerization initiator 2-methyl-1- [4- (methylthio) phenyl] -2
Morpholino-1-propanone and 2,4-diethylthioxanthone are added to the sum of
0% was added.

G. Plasticizer Dibutyl phthalate (DBP) was added at 10% of the polymer.

H. SiO ₂ dissolved in the thickener 2- (2-butoxyethoxy) ethyl acetate (concentration 15%) was added 4% relative to the polymer.

A. Preparation of Organic Vehicle The solvent and the polymer were mixed and heated to 60 ° C. with stirring to dissolve all the polymers homogeneously. Then the solution is cooled to room temperature.

B. Preparation of paste Add conductive powder, glass frit, monomer, photopolymerization initiator, plasticizer, thickener and solvent to the above organic vehicle so as to have a predetermined composition, and mix and disperse with three rollers to paste. Was prepared.

C. Restoration The above paste was applied by attaching the paste to a needle having a flat tip and making contact with a disconnection defect of the electrode. Thereafter, the applied paste was irradiated with a YAG laser to sinter the paste.

D. Evaluation The repaired electrode was examined for steps, cracks, and peeling at the repaired location. In each case, there was no step and no peeling occurred.

Comparative Examples 1 to 3 Pastes were prepared under the same conditions as in the above Examples except that Ag powders as shown in Table 2 were used, and the disconnection defects of the electrodes were repaired.

The repaired electrode was examined for steps and peeling at the repaired portion in the same manner as in the example. In some cases, peeling occurred at the repaired part. In each case, a step was generated, and when the dielectric layers were laminated, cracks occurred at the repaired portions.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

According to the present invention, a disconnection defect of an electrode having a high definition and a fine pattern can be surely repaired without peeling or a step.

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Claims (7)

[Claims] 1. An average particle size of conductive powder contained in a repairing conductive paste when repairing a disconnection defect portion of an electrode using a repairing conductive paste on a substrate on which an electrode is formed using the conductive paste. The diameter A is the average particle diameter α of the conductive powder contained in the conductive paste used for forming the electrode.
And an electrode disconnection repairing method characterized by satisfying the following relationship. 0.01 × α ≦ A ≦ 2 × α 2. The repairing conductive paste is made of Ag, Au, P
2. The electrode disconnection repairing method according to claim 1, comprising a conductive powder containing at least one selected from the group consisting of d, Ni and Pt. 3. The method according to claim 1, wherein the repairing conductive paste is a photosensitive conductive paste. 4. The method according to claim 1, wherein the repairing conductive paste contains glass frit. 5. The method according to claim 1, wherein the same conductive paste as that used for forming the electrode is used as the repairing conductive paste. 6. The method according to claim 1, wherein the electrode is a display electrode. 7. The method according to claim 1, wherein the electrode is an electrode for a plasma display.