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US 12,381,136 B2Granted
Lead frame and manufacturing method thereof
AssigneeDai Nippon Printing Co., Ltd.
InventorsMasahiro Nagata, Kazuhiro Shinozaki, Masahiro Yamada, Daisuke Okuyama, Chiaki Hatsuta, Kentarou Seki, Hideto Matsui, Kazunori Oouchi
Life of this patent
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Abstract
A lead frame includes a plurality of lead portions. At least a part of an upper surface of the lead portion and a sidewall surface of the lead portion is a rough surface having been subjected to roughening treatment. A value of a* in a CIELab color space of the rough surface is within a range from 12 to 19, and a value of b* is within a range from 12 to 17.
Claims9
A lead frame, comprising:
- a die pad on which a semiconductor element is mountable;
- and
- a lead portion located around the die pad, wherein:
- an area of a smooth surface is formed in a front surface of the die pad or a front surface of the lead portion,
- an area of a rough surface exists in such a way as to surround an entire perimeter of the area of the smooth surface,
- the area of the smooth surface is made of a same material as the area of the rough surface, and
- the area of the smooth surface has a circular, elliptical, or oblong shape in a plan view.
4 more elements
A method of manufacturing a lead frame, comprising:
- a step of preparing a metal substrate;
- a step of forming a die pad and a lead portion located around the die pad by etching the metal substrate;
- a step of forming a plating layer on a part of the metal substrate;
- a step of forming a rough surface at, of the metal substrate, a part that is not covered by the plating layer;
- and
- a step of removing the plating layer, wherein
- an area of a smooth surface is formed in a front surface of the die pad or a front surface of the lead portion, and
- an area of the rough surface exists in such a way as to surround an entire perimeter of the area of the smooth surface.
5 more elements
Dependencies are inferred from the claim text.