Abstract: A lead frame includes a dam bar and leads connected by the dam bar. Each lead includes an inner lead, which is located at one side of the dam bar, and an outer lead, which is located at the other side of the dam bar and formed integrally with the inner lead. Each inner lead includes a basal portion located at a side closer to the dam bar, a distal portion located at the opposite side of the basal portion, and an intermediate portion connecting the distal and basal portions and having a width that differs from the distal portion. A plating layer covers an upper surface and a side surface of the distal portion and at least part of a side surface of the intermediate portion. Side surfaces of the basal portion and the dam bar are entirely located outside the plating layer.

Abstract: A lead frame includes a dam bar and leads connected by the dam bar. Each lead includes an inner lead, which is located at one side of the dam bar, and an outer lead, which is located at the other side of the dam bar and formed integrally with the inner lead. Each inner lead includes a basal portion located at a side closer to the dam bar, a distal portion located at the opposite side of the basal portion, and an intermediate portion connecting the distal and basal portions and having a width that differs from the distal portion. A plating layer covers an upper surface and a side surface of the distal portion and at least part of a side surface of the intermediate portion. Side surfaces of the basal portion and the dam bar are entirely located outside the plating layer.

Abstract: There are provided the steps of forming a plurality of opening portions by punching predetermined portions of a metal plate, forming crushed portions by pushing crushed margin portions, which are defined in vicinity of both side edge portions of the opening portions of the metal plate, to reduce a thickness, defining a width W3 between a side surface portion and a center portion to assure an interval between lead portions and also defining a width of a top end portion and a width of a base portion by punching center portions of the crushed portions except predetermined both-side portions and portions in vicinity of peripheral portions in which the crushed portions of the opening portions of the metal plate are not present, and defining the top end portions by punching a predetermined portion of the top end portion.

Abstract: In a lead frame which comprises lead portions extended from a frame portion toward an inside like a teeth of a comb and each having a top end portion, a center portion, and a base portion connected to the frame portion, the top end portion and the center portion are connected via a first constriction portion, and the center portion and the base portion are connected via a second constriction portion, and thickness of both side surface portions of the center portion and the top end portion of each lead portion are set thinner than thickness of remaining portions of each lead portion.

Abstract: There are provided the steps of forming a plurality of opening portions by punching predetermined portions of a metal plate, forming crushed portions by pushing crushed margin portions, which are defined in vicinity of both side edge portions of the opening portions of the metal plate, to reduce a thickness, defining a width W3 between a side surface portion and a center portion to assure an interval between lead portions and also defining a width of a top end portion and a width of a base portion by punching center portions of the crushed portions except predetermined both-side portions and portions in vicinity of peripheral portions in which the crushed portions of the opening portions of the metal plate are not present, and defining the top end portions by punching a predetermined portion of the top end portion.

Abstract: In a lead frame which comprises lead portions extended from a frame portion toward an inside like a teeth of a comb and each having a top end portion, a center portion, and a base portion connected to the frame portion, the top end portion and the center portion are connected via a first constriction portion, and the center portion and the base portion are connected via a second constriction portion, and thickness of both side surface portions of the center portion and the top end portion of each lead portion are set thinner than thickness of remaining portions of each lead portion.