Conductive-pattern forming method and composition for forming conductive pattern by photo irradiation or microwave heating
Provided are a conductive pattern forming method and a composition for forming a conductive pattern by photo irradiation or microwave heating, capable of increasing the conductivity of the conductive pattern. A conductive pattern is formed by preparing a composition for forming a conductive pattern comprising, copper particles each having a copper oxide thin film on the entirety or a part of the surface thereof, copper oxide particles, a reducing agent such as a polyhydric alcohol, a carboxylic acid, or a polyalkylene glycol, and a binder resin; forming a printed pattern having any selected shape on a substrate using this composition for forming a conductive pattern; and subjecting the printed pattern to photo irradiation or microwave heating to generate a sintered body of copper.
1. A composition for forming a conductive pattern by photo irradiation or microwave heating, comprising,
copper particles each having a copper oxide thin film on the entirety or a part of a surface thereof,
copper oxide particles having a diameter smaller than that of the copper particles,
a reducing agent, and
a binder resin;
wherein the copper particles have a number median particle diameter D50 of 100 nm to 10 μm, and the copper oxide particles have a number median particle diameter D50 of 5 nm to 1000 nm.
2. A composition for forming a conductive pattern according to claim 1 , wherein a mass ratio of the copper particles and the copper oxide particles is represented by copper particles:copper oxide particles=98:2 to 50:50.
3. A composition for forming a conductive pattern according to claim 1 , wherein the copper oxide particles are copper (I) oxide particles, copper (II) oxide particles, or a mixture of these particles.
4. A composition for forming a conductive pattern according to claim 1 , wherein the reducing agent is a polyhydric alcohol, a carboxylic acid, or a polyalkylene glycol.
5. A composition for forming a conductive pattern according to claim 1 , wherein the copper particles have a number median particle diameter D50 of 500 nm to 3 μm.
6. A composition for forming a conductive pattern according to claim 1 , wherein the ratio of copper oxide in the copper particles is 20% by mass or less relative to the total amount of metal copper and copper oxide.
7. A method for forming a conductive pattern comprising, preparing a composition for forming a conductive pattern according to claim 1 , and subjecting the composition for forming a conductive pattern to photo irradiation or microwave heating.
8. A conductive pattern forming method according to claim 7 , wherein the light to be irradiated to the composition for forming a conductive pattern is a pulsed light having a wavelength of 200 to 3000 nm.
9. A conductive pattern forming method according to claim 7 , wherein the microwave to heat the composition for forming a conductive pattern has a wavelength of 1 m to 1 mm.