Patent ID: 7015583

Claim:
A submount, comprising: (a) a submount substrate; (b) a solder layer that: (b1) is formed at the top surface of the submount substrate; and (b2) is composed of lead-free solder; and (c) a solder intimate-contact layer that: (c1) is formed between the submount substrate and the solder layer; (c2) has a structure in which: (c2a) one precious metal layer consisting mainly of at least one type of precious metal is formed at the solder layer-side face; and (c2b) a transition element layer consisting mainly of at least one type of transition element is formed at the submount substrate-side face of the one precious metal layer such that the transition element layer makes surface contact with the one precious metal layer; and (c3) is formed such that the solder intimate-contact layer's face at the solder-layer side makes surface contact with the solder layer; the submount, when a semiconductor light-emitting device is bonded to the solder layer, having a bonding strength of at least 40 MPa with the semiconductor light-emitting device.