Provided is a metal jointed body, joined by solid-phase joining in the atmosphere, in which no protrusion of molten joining material occurs, that improves dimensional stability. A metal jointed body is formed by (A) making Ag films of two metal laminated bodies opposed to each other, the metal jointed body being configured by sequentially laminating a Zn film and an Ag film on an Al substrate serving as a member to be joined, and (B) bringing the Ag films into contact with each other, then (C) heating is performed while pressurizing, and closely adhering and solid-phase joining the Ag films to each other. The completed metal jointed body is a portion where AlAg alloy layers are provided on both sides of an AgZnAl alloy layer to join the Al substrates to each other.

An integrated circuit package may include a die and a lid over the die. An solder preform core is between the die and the lid. A first intermetallic layer (IML) is between the die and the solder preform and a second intermetallic layer (IML) is between the lid and the solder preform, wherein the first IML and the second IML comprise low-temperature solder (LTS) material.