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A paste composed of micrometer-sized Ag particles and an organic solvent formed a soft porous bonding layer under atmospheric conditions at 200°C and above. Using this Ag paste for die-bonding of a light-emitting diode (LED) resulted in excellent thermal resistance and reliability. Ag/Ag interactions are thought to be responsible for internal bonding, and the Ag paste does not bond strongly to other materials. To ameliorate this, polymer particles were added to the Ag paste. The flow starting temperature of the polymer did not hinder the sintering of Ag particles, and the melted polymer particles served as an adhesive. The polymer-containing Ag paste had a lower specific resistance than that of the conventional conductive adhesives, so could be treated using low-temperature processes. The presence of polymer improved the die-shearing strength during the bonding of LED die to the plastic substrate.