Abstract: A lid material (1) according to the present invention comprises: a base layer (2) composed of a low thermal expansion metal; an intermediate metal layer (3) provided on one surface of the base layer (2) and composed of a low proof stress metal having a proof stress of not greater than 110 N/mm2; and a brazing material layer (4) provided on the intermediate metal layer (3) and composed of a silver brazing alloy mainly comprising silver. The intermediate metal layer (3) and the brazing material layer (4) are press- and diffusion-bonded to each other, and the brazing material layer (4) has a blistered area ratio of not greater than 0.5% as observed on an outer surface of the brazing material layer. The low proof stress metal is preferably oxygen-free copper. A lid produced from the lid material (1) exhibits an excellent bonding property when the lid is brazed to a case mainly composed of a ceramic material for an electronic component package.

Abstract: An electronic component package according to the present invention includes a case (1) having a cavity portion containing an electronic component therein, and a lid member (8) fusion-welded to the case (1) via a fusion-welding layer (20) to close the cavity portion hermetically. The case (1) has a first metal layer (5) laminated on the case (1) in a manner to be exposed on the cavity open side. The lid member (8) has a core portion (9), and a second metal layer (10) laminated on a side of the core portion (9) facing the case (1). The fusion-welding layer (20) has a soldering material layer (12A) formed of a soldering material, and first and second intermetallic compound layers (5A) and (10A), respectively, formed on opposite sides of the soldering material layer (12A) as a result of diffusion of a major component of the soldering material into the first metal layer (5) and the second metal layer (10).