COPPER PASTE FOR PRINTED WIRING BOARD, AND PRINTED WIRING BOARD USING IT

• Main Authors: SHIMAMURA HIROYUKI, SASAKI TAKUYA, YOSHIMARU KATSUHIKO, UWAZUMI YOSHIAKI, SAKAGAMI TAKAHIKO
• Format: Patent
• Language: English
• Published: 12.08.2004
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; CABLES; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CONDUCTORS; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INSULATORS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; PRINTED CIRCUITS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING ORDIELECTRIC PROPERTIES

PROBLEM TO BE SOLVED: To provide copper paste with excellent filling capability for a via hole of a printed wiring board or the like and having low viscosity; and to provide a printed wiring board using the copper paste. SOLUTION: This copper paste comprises an organic vehicle and copper powder and is used for forming a conductor of the printed wiring board. The copper powder is prepared by applying a surface treatment by a carboxylic acid-containing organic solvent, and by applying a re-powdering treatment by using a wind power circulator. The copper powder used in this case is provided with the following respective powder characteristics (1)-(4): (1) the average particle diameter D50by a laser diffraction scatter type particle size distribution measurement method of the copper powder is 3.7-6.9 μm; (2) the value of the degree of aggregation expressed by D50/DIAby using the average particle diameter D50by the laser diffraction scatter type particle size distribution measurement method of the copper powder and the average particle diameter DIAobtained by an image analysis is 1.2-1.7; (3) the specific surface area of the copper powder is 0.16-0.30 m2/g; and (4) the tap fill density is above 4.8 g/cm3. COPYRIGHT: (C)2004,JPO&NCIPI