Conductive adhesive, and circuit board and electronic component module using the same

A conductive adhesive comprising:

• 82 wt % of Sn—Bi system solder powder and;
• 18 wt % of an adhesive containing organic acid, wherein
• the Sn—Bi system solder powder is composed of solder particles having a particle size L1 of 20 to 30 μm and solder particles having a particle size L2 of 8 to 12 μm,
• the particle size L1 is represented by a median diameter (D50) which is a particle size where an integrated particle amount is 50%,
• the particle size L2 is represented by a median diameter (D50) which is a particle size where an integrated particle amount is 50%,
• a mixing ratio of the Sn—Bi system solder powder is such that the solder particles having the particle size L1 of 20 to 30 μm occupy 70 wt % with respect to the whole solder powder, and 30 wt % is occupied by solder particles having the particle size L2 of 8 to 12 μm,
• a solder composition of the Sn—Bi system solder powder is 42 wt % Sn-58 wt % Bi, and
• the adhesive containing organic acid is made up of 16 wt % of bisphenol A type epoxy resin, 62 wt % of bisphenol F type epoxy resin, 12 wt % of imidazole system curing agent, 3.0 wt % of adipic acid, 6.0 wt % of glutaric acid, and 1.0 wt % of thicking agent.