Manufacture of lead frame

Abstract

Abstract PURPOSE:To prevent the occurrence of cracks of the sealing resin by a method wherein in bending the support bar by a depress process after forming the pattern of a lead frame, the pepriphery of the die pad is simultaneously bent to the chip mounting side thereby to eliminating a sharp edge on the peripheral edge face of the die pad. CONSTITUTION:The pattern of a lead frame is formed by a press processing method. In this pattern, a die pad 11 is formed so that it becomes larger than the ordinary size, and at the boundary of the die pad 11 and a support bar 17, notches are inwardly formed along the end faces of the support bar. Then by swaging, the edge of the peripheral end face of the die pad 11 is rounded. Finally, a bending deformation is given to the support bar in a depress metal mold and simultaneously, a drawing deformation is given to the peripheral part R of the die pad with the same angle as the depress angle of the support bar. With this, the occurrence of the cracks of the sealing resin is prevented.

Inventors

• 👤 Katsufusa Fujita
• 👤 勝房 藤田
• 👤 Shigeaki Kubota
• 👤 久保田　恵彬

Bibliographic Details