Leadframe designs for plastic overmold packages
AssigneeAgere Systems Inc.
InventorsDavid M. Boulin, Hugo F. Safar
Life of this patent
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Abstract
The specification describes a plastic overmolded package for high power devices that has a very low lead count, typically fewer than eight, and in a preferred embodiment, only two. The leads occupy essentially the same linear space as the multiple leads in a conventional package and thus have a wide-blade configuration. To improve mechanical integrity, the leads in the package are provided with retention slots to add back the equivalent of the plastic joints in the spaces that were eliminated due to the wide-blade design. The retention slots extend in the width dimension of the leads.
Claims7
A plastic overmolded package comprising:
- a. a leadframe, the leadframe having a top side and a bottom side, and comprising:
- i. a die attachment portion on the top side of the leadframe,
- ii. at least one semiconductor device attached to the die attachment portion on the top side substrate, with the bottom side of the leadframe devoid of a semiconductor device,
- iii. at least two tab leads extending from the center die attachment portion, the tab leads having a width W and a thickness T,
- iv. at least one slot formed in each of the tab leads, each slot having a width W and a length L, wherein length L is substantially greater than width W, and wherein the length L of the slot extends along the width W of the tab lead, and further wherein each slot extends through the thickness T of the tab lead thus providing an inboard slot edge nearest to a semiconductor device and an outboard slot edge furthest from the device,
- b. a plastic overmold comprising an integral body having a top, a bottom and sidewalls, the plastic overmold filling each slot and additionally encapsulating the semiconductor device and the bottom of the leadframe while leaving a portion of the tab leads exposed, the exposed portions of the tab leads extending away from the sidewalls of the overmold.
Dependencies are inferred from the claim text.