PURPOSE: To acquire a package whose heat mechanical processing property is good leaving electromagnetic wave shield property as it is and dissipation property is improved without being restricted in formation of package structure by making at least a part of a metallic plate of a metallic base substrate which is relevant to the rear of an opening part of a package thicker than a metallic plate corresponding to a brim part.
CONSTITUTION: After circuit processing is performed for a surface of a copper foil 103 by using a metallic base substrate wherein the copper foil 103 and a metallic plate 101 are laminated through an insulating layer 102, bending or squeezing processing is carried out to process it to a shape with an opening part 105. A brim part 104 with a lead part acquired by circuit processing whose purpose is connection with other circuit substrate is further provided to a circumferencial edge of an opening surface. In such an electronic circuit package 100, at least a part of the metallic plate 101 of a metallic base substrate which is relevant to the rear of the opening part 105 of the package 100 is made thicker than a metallic plate corresponding to the brim part 104. Furthermore, for example, a surface which is relevant to the rear of the package opening part 105 of the metallic plate 101 is made irregular.
OISHI YOSHIKAZU
ISHIKAWA TAKAYUKI
TAKAHASHI SEIICHI
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