초록 ▼

Thick film conductive copper pastes that are lead-free and cadmium-free. The inventive copper pastes possess desirable characteristics, including good solderability, good wire bondability, a low firing temperature, and a wide temperature processing window, and provide excellent adhesion to a variety

Thick film conductive copper pastes that are lead-free and cadmium-free. The inventive copper pastes possess desirable characteristics, including good solderability, good wire bondability, a low firing temperature, and a wide temperature processing window, and provide excellent adhesion to a variety of substrates, including alumina and glass coated stainless steel substrates, as well as low resistivity, and a microstructure after firing that is dense and substantially free of pores.

대표청구항 ▼

What is claimed is: 1. A conductive thick film paste comprising a solids portion comprising a glass component and a metal component, said glass component comprising: a. a first glass composition comprising in mole %, i. about 5 to about 35% ZnO, ii. about 5 to about 40% SiO2, and iii. about 2 to a

What is claimed is: 1. A conductive thick film paste comprising a solids portion comprising a glass component and a metal component, said glass component comprising: a. a first glass composition comprising in mole %, i. about 5 to about 35% ZnO, ii. about 5 to about 40% SiO2, and iii. about 2 to about 35% B2O3, b. a second glass composition comprising in mole %, i. about 20 to about 70% Bi2O3, ii. about 20 to about 50% SiO2, and iii. about 2 to about 30% B2O3, c. a third glass composition comprising in mole %, about 5 to about 80% Bi2O3, d. no lead or lead oxide, and e. no cadmium or cadmium oxide. 2. The thick film paste of claim 1, wherein the first glass composition further comprises about 0.1 to about 25 mol % CuO. 3. The thick film paste of claim 1, wherein the first glass composition further comprises about 0.1 to about 10 mol % NiO. 4. The thick film paste of claim 1, wherein the ZnO content of the second glass composition is about 10 to about 30 mol %. 5. The thick film paste of claim 2, wherein the ZnO content of the second glass composition is about 10 to about 30 mol %. 6. The thick film paste of claim 3, wherein the ZnO content of The second glass composition is about 10 to about 30 mol %. 7. The thick film paste of claim 3, wherein the first glass composition comprises about 15 to about 65 mol % Bi2O3. 8. The thick film paste of claim 3, wherein the first glass composition comprises about 15 to about 50 mol % Bi2O3. 9. The thick film paste of claim 1, wherein the metal component comprises copper. 10. The thick film paste of claim 9, wherein the copper is in the form of first and second powders having a bimodal size distribution, said first powder having a size distribution described by d10=0.1-0.3 microns, d50=0.6-1.1 microns and d90=1.5-3.5 microns, and said second powder having a size distribution described by d10=2-5 microns; d50=3-8 microns; and d90=15-25 microns. 11. A method of making an electronic device comprising: a. providing a substrate and conductive thick film paste comprising a solids portion, wherein the paste comprises a glass component and a metal component, wherein the glass component comprises: i. a first glass composition comprising in mole %: 1. about 5 to about 35% ZnO, 2. about 5 to about 40% SiO2, and 3. about 2 to about 35% B2O3, ii. a second glass composition comprising in mole %: 1. about 20 to about 70% Bi2O3, 2. about 20 to about 50 % SiO2, and 3. about 2 to about 30% B2O3, iii. a third glass composition comprising in mole %, about 5 to about 80% Bi2O3, iv. no lead or lead oxide, and v. no cadmium or cadmium oxide, b. applying said paste upon said substrate; c. firing the paste and substrate at a temperature of from about 650�� to about 850�� C. 12. The method of claim 11, wherein the metal component comprises copper. 13. The method of claim 12, wherein the copper is in the form of a powder having a particle size of about 0.1 micron to about 30 microns. 14. The method of claim 12, wherein the copper is in the form of first and second powders having a bimodal size distribution, said first powder having a size distribution described by d10=0.1-0.3 microns, d50=0.6-1.1 microns and d90=1.5-3.5 microns, and said second powder having a size distribution described by d10=2-5 microns; d50=3-8 microns; and d90=15-25 microns. 15. The method of claim 11, wherein said substrate is selected from the group consisting of an alumina substrate, a porcelain enamel coated steel substrate, a beryllia substrate, a barium titanate substrate, an aluminum nitride substrate and a silicon carbide substrate.