| 摘要 |
A method for forming a plastic package (35) for a power semiconductor electronic device to be encapsulated within a plastic case (2) and to be coupled thermally to a heat sink element (25) having a major surface (27) exposed and at least one peripheral portion (36) extending outwards from at least one side of the plastic case (2), of the type wherein it provides for forming the plastic case (2) of the package by molding inside a main cavity (24) of a mold (23) after positioning the heat sink element (25) with this major surface (27) in contact with the bottom of a suitable housing (26) provided in a lower portion of the mold (23) which opens into the main cavity (24) of the mold. According to the invention, the following steps are provided: forming the heat sink element (25) such that at least side surfaces (29) jutting out of said side of the plastic case (2) are, at least in a zone adjacent to that side and in the peripheral portion (36), inclined to form an angle ( alpha ) substantially greater than zero with a normal line (N) to the major surface (27), so as to have a negative slope from outside; correspondingly forming the housing (26) such that its inner walls (28) facing said side surfaces (29) of the heat sink element are inclined, at least in that zone, to form an angle substantially equal to the angle ( alpha ) with the normal line (N), with a positive slope from the housing interior; and providing thrust means (30) which, when the mold (23) is closed, are engaged from above with at least part of the peripheral portion (36) of the heat sink element (25) to exert thereon a compressive force substantially toward the housing (26) bottom and which is effective to hermetically seal temporarily the side surfaces (29) of the heat sink element and the inner walls (28) of the housing in the zone adjacent to said side of the plastic case. <IMAGE> |
