Hitachi Construction Machinery Co., Ltd.

Nobuhiko Tada

Shigeyuki Sakurai

Naoki Miyanagi

Yoshiaki Shimomura

Yoshinari Nagano

Shinya Okumura

Kojiro Ogata

Yasushi Minomoto

Laser processing apparatus, laser processing method and dam bar

Dam bar cutting apparatus and dam bar cutting method

Lead frame fabricating method and lead frame fabricating apparatus

Metal plate processing method, lead frame processing method, lead frame,

In a method for forming a lead frame (1) from a metallic plate, a metallic plate (11) is first etched to form outer leads (4) and outer portions (3b) of inner leads of the lead frame (1). Inner portions (3a) of the inner leads (3) are then laser-cut under the condition that a joint portion (7) is left so as to interconnect the inner leads (3) at their distal ends. Mechanical surface treatment and chemical surface treatment are then carried out to remove dross (10), spatters (9) and oxide films deposited during the laser cutting. Inner areas of the inner leads (3) connected to respective terminals of a semiconductor chip are then plated with gold to form plated terminal portions (3A). Subsequently, the region of the lead frame other than the outer leads (4) is coated with a protective film for solder plating and the outer leads (4) are plated with solder. The joint portion (7) left at the distal ends of the inner leads (3) is then cut off by laser cutting so that the inner leads (3) are separated from one another, thereby forming a final lead frame pattern. The protective film for solder plating is then removed, followed by washing and drying. The inner leads (3) are prevented from being curved due to thermal deformations with the laser cutting, resulting in highly accurate processing.

Lead frame processing method

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Ushiku, Japan

Nobuhiko Tada