Patent ID: 8692127

Claim:
A terminal structure comprising: a terminal having: a conductor layer containing at least one metal selected from gold, silver, and copper; a first layer containing nickel and phosphorus, laid on the conductor layer; a second layer having a smaller atomic ratio of nickel to phosphorus than the first layer and containing Ni 3 P, laid on the first layer; a third layer containing a first internetallic compound of an Ni—P—Sn type, laid on the second layer; and a fourth layer containing a second intermetallic compound of an Ni—Cu—Sn type, laid on the third layer; and a solder layer on the fourth layer of the terminal, wherein Ra2 is larger than Ra1, where Ra1 is a surface roughness of the third layer on the second layer side and Ra2 is a surface roughness of the third layer on the fourth layer side.