Leadframe with dot array of silver-plated regions on die pad for use in exposed-pad semiconductor package

Abstract

A leadframe with a dot array of silver-plated regions on die pad is proposed, which is designed specifically for use in the construction of an exposed-pad type of semiconductor package. The proposed leadframe is characterized by that the front side of the die pad is partitioned into a centrally-located die-mounting area and a peripherally-located ground-wire bonding area; and wherein the die-mounting area is selectively silver-plated to form a dot array of silver-plated regions, while the peripheral area of the die pad is entirely silver-plated to form a silver-plated peripheral area. In addition, the die-mounting area of the die pad can be further formed with a plurality of dimples for the purpose of increasing the contact area between the die pad and a silver-epoxy layer that is to be pasted over the die-mounting area for use to adhere a semiconductor chip to the die pad. Owing to the provision of the dot array of silver-plated regions within the die-mounting area, it allows a better electrical coupling between the die pad and the inactive surface of the semiconductor chip than the conventional ring plating scheme so that the packaged semiconductor chip can have a better grounding effect, and also allows the silver-epoxy layer to be better adhered to the die pad than the conventional spotted plating scheme to prevent delamination.