Leadframe and resin-sealed semiconductor device
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United States of America Patent
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Nov 22, 1994
Grant Date -
N/A
app pub date -
Sep 16, 1992
filing date -
Sep 18, 1991
priority date (Note) -
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Abstract
A lead frame body having a chip mounting surface comprises first, second and third successive, laminated layers each having lower and upper surface, the lower main surface of the first layer defining a bottom main surface of the lead frame body and the upper main surface of the third layer defining the chip-mounting surface of the lead frame body. The first, second and third layers are formed of respective, different materials, the material of the second layer having a higher etching rate than the respective etching rate of the materials of the first and third layers. A plurality of spaced openings are formed in the first layer and which respectively correspond to and are in communication with a corresponding plurality of spaced hollow cavities in the second layer. The interior dimensions of the hollow cavities are greater than the corresponding interior dimensions of the respective openings, producing an annular lip of the material of the first layer at each opening which extends inwardly relatively to the respective hollow cavity.
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