Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Metallic housing or support
Patent
1996-09-20
1998-04-07
Niebling, John
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Metallic housing or support
438106, 257676, H01L 2160
Patent
active
057364320
ABSTRACT:
A variety of lead configurations for use in packaged semiconductors, the leads including integral finger locking mechanisms to prevent leads from pulling out of an encapsulated package, and their method of manufacture. Each finger is comprised of a bent portion of the lead and has a length of approximately two to four times the thickness of the lead body. A finger may be integrally located at the lead tip or, where the lead includes one or more tabs, a finger may extend from any number of the tab edges. Any number of leads within a semiconductor package may incorporate a finger, and each lead may incorporate a plurality of fingers. A method of manufacturing the finger locking mechanism of the current invention includes forming a lead frame in a conductive strip, wherein the lead tips are separated from the die attach pad, so as to retain a sufficient length of each lead in appropriate locations to accommodate the formation of fingers by bending. In the case of a finger extending from a tab, the tab is separated from the lead body by a length equal to the intended length of the finger to be formed. The process further includes the bending of the one or more fingers, the process further includes downsetting of the die attach pad. The step of bending the finger is accomplished during the step of forming the leads or, in the case where the lead frame includes a die attach pad that is to be downset, during downsetting. After the integrated circuit is assembled, it is encapsulated in plastic, whereby the finger locking mechanisms engage the encapsulating material to inhibit movement of the associated leads with respect to the plastic encapsulating material.
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National Semiconductor Corporation
Niebling John
Turner Kevin F.
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