Patent ID: 8821676

Claim:
A bonding method for electrically connecting an electrode of an electronic element and a wiring of a wiring substrate, comprising: applying a bonding material comprising a first portion of metal particles having an average particle size of 100 nm or less, the metal particles being coated with an organic substance having carbon atoms of 2 to 8, wherein the first portion of metal particles has at least one first peak of a particle size distribution based on a volumetric base to a bonding face where the electrode of the electronic element is to be placed on the wiring substrate, and a second portion of metal particles having an average particle size of 100 nm to 100 μm, wherein the second portion of metal particles comprises aggregated particles produced by evaporating a solvent from the metal particles of 100 nm or less coated with an organic substance having carbon atoms of 2 to 8, and wherein the second portion of metal particles has at least one second peak of a particle size distribution, different from the at least one first peak, based on a volumetric base to a bonding face where the electrode of the electronic element is to be placed on the wiring substrate; mounting an electronic element on the bonding material; and heating the electrode at least in the bonding area under a pressure thereby bonding the electrode and the wiring of the wiring substrate.