US 12,740,437 B2Granted

Lead frame

AssigneeChang Wah Technology Co., Ltd.

InventorsKeiichi Otaki, Naoki Haruzono, Ichinori Iidani

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Abstract

A lead frame formed of a plate-shaped copper material, at least one surface of which being smooth, comprising: a predetermined connection plating layer being provided at a portion to be connected for conduction of a semiconductor element on the smooth surface of the plate-shaped copper material; a portion where the smooth surface of the copper material exposed in an annular shape being provided around the connection plating layer; and an anodic oxide film of the copper material being provided at other portions. With this composition, the lead frame of the present disclosure, without having a roughening relaxation area, may be suitable for connection by solder connection or die attach material in the portion to be connected for conduction of semiconductor elements, may have excellent adhesion with sealing resin when a semiconductor package is manufactured by resin sealing, and may be manufactured efficiently and at a low cost.

Claims2

Dependent claims

A lead frame formed of a plate-shaped copper substrate, comprising:

a smooth surface with a surface area ratio of 1.0 to 1.3 being provided on at least one surface of the plate-shaped copper substrate;
a predetermined connection plating layer being provided at a portion of the smooth surface of the plate-shaped copper substrate for conduction of a semiconductor element;
an annular portion, where the smooth surface of the plate-shaped copper substrate is annularly exposed, being provided around the predetermined connection plating layer, the annular portion having a width of 5 to 20 micrometers;
and
an anodic oxide film with a surface area ratio of 1.7 to 2.3 being provided on the at least one surface of the plate-shaped copper substrate outside of the smooth surface,
wherein the anodic oxide film is formed of a monolayer film of copper oxide having needle-shaped crystal structures with an average length of more than 200 nanometers, the monolayer film of copper oxide being composed of a mixture of cuprous oxide (Cu2O), cupric oxide (CuO) and cupric hydroxide (Cu(OH)2).

3 more elements

Dependencies are inferred from the claim text.