Bonding composition, conductor bonding structure, and method for producing same

A method for bonding conductors, the method comprising:

• applying onto a surface of a first conductor a bonding composition comprising copper powder, a liquid medium and a reducing agent to form a coating film:
• drying the coating film to obtain a dried coating film:
• applying a second conductor onto the dried coating film to interpose the dried coating film between the first conductor and the second conductor;
• and
• sintering, under pressure, the copper powder contained in the dried coating film to bond the first conductor and the second conductor,
• wherein the reducing agent has a boiling point that is higher than the boiling point of the liquid medium,
• the reducing agent has a melting point that is equal to or below the sintering temperature of the copper powder,
• the liquid medium comprises an alcohol having a boiling point of 188° C. or higher and lower than 300° ° C.,
• a proportion of the liquid medium is from 10 parts to 40 parts by mass with respect to 100 parts by mass of the copper powder, and
• the reducing agent contains at least one amino group and a plurality of hydroxyl groups.

A bonding composition used for bonding a first conductor and a second conductor under pressure, wherein:

• the bonding composition comprises copper powder, a liquid medium and a reducing agent, the reducing agent has a boiling point that is higher than the boiling point of the liquid medium,
• the reducing agent has a melting point that is equal to or below the sintering temperature of the copper powder,
• the liquid medium comprises an alcohol having a boiling point of 188° C. or higher and lower than 300° C.,
• a proportion of the liquid medium is from 10 parts to 40 parts by mass with respect to 100 parts by mass of the copper powder, and
• the reducing agent contains at least one amino group and a plurality of hydroxyl groups.

A conductor bonding structure, in which two conductors are electrically connected by a joint portion, wherein:

• the joint portion comprises a material constituted mainly by copper;
• and
• a moiety (3) shown below is formed in the joint portion:
• wherein:
• R3 to R5 each independently represent a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and containing a hydroxyl group.