| 摘要 |
PROBLEM TO BE SOLVED: To improve a product yield while lowering a wiring resistance and securing a sufficient bonding strength in relation to a board by specifying a shape factor of the copper powder in the copper conductive paste including an organic vehicle. SOLUTION: A shape factor of the copper powder in the copper conductive paste including copper powder and an organic vehicle is set in a range at 1.0-2.0. The shape factor is an index for showing sphericity of grains, and as the factor is close to 1, the sphericity is close to a sphere. Since the copper powder having a shape factor at 1.0-2.0 close to the sphere is included, dry filling ratio can be raised. Consequently, sintering density can be raised. The mean diameter of this copper powder desirable exists in a range at 0.5-10μm. Content of the copper powder in the copper conductive paste desirably exists in a range at 60-95 wt.%. As a organic vehicle, ethyl cellulose group resin, alkyd-based resin or acrylic resin dissolved by the terpineol-based solvent or the alcohol group solvent is used.
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