PURPOSE: To provide a lead frame and a manufacturing method thereof in which the lead frame can be manufactured finely and accurately with no thermal influence.
CONSTITUTION: A metal plate 301 is coated, on the opposite sides thereof, with a thin copper film 1 reflecting the laser beam highly efficiently. The thin copper film 1 is then subjected to etching to form an opening 3 of predetermined pattern based on the profile of lead frame. The metal plate 301 exposed at the opening 3 is then irradiated with a condensed laser beam to make a hole 4 thermally in the metal plate 301 thus manufacturing a lead frame having predetermined shape. In this regard, the laser beam has an elongated elliptical cross- section with the long axis thereof being aligned substantially with the boring direction.
MITSUYANAGI NAOKI
SHIMOMURA YOSHIAKI
SAKURAI SHIGEYUKI
NAGANO YOSHIYA
