Gem Services, Inc.

Other

Advanced Analogic Technologies Incorporated

Allen K Lam

Richard Kent Williams

Anthony Chia

James Harnden

Chu Weibing

Alex K Choi

Alexander K Choi

Efficient utilization of space in a laterally-conducting semiconductor device package is enhanced by creating at least one supplemental downbond pad portion of the diepad for receiving the downbond wire from the ground contact of the device. The supplemental diepad portion may occupy area at the end or side of the package formerly occupied by non-integral leads. By receiving the substrate downbond wire, the supplemental diepad portion allows a greater area of the main diepad to be occupied by a die having a larger area, thereby enhancing space efficiency of the package.

Space-efficient package for laterally conducting device

Portion of a matrix for surface mount package leadframe

A semiconductor package contains a plurality of sheet metal leads that are attached to one or more terminals on a top side of a semiconductor die. A heat sink is attached to a terminal on a bottom side of the die. Each of the leads extends across the die and beyond opposite edges of the die and is symmetrical about an axis of the die. At the locations where the leads pass over the edges of the die notches are formed on the sides of the leads which face the die, thereby assuring that there is no contact between the leads and the peripheral portion of the top surface of the die. Particularly in power MOSFETs the peripheral portion of the top surface normally contains an equipotential ring which is directly connected to the backside (drain) of the MOSFET, and hence a short between the leads on the top of the die and the equipotential ring would destroy the device. The result is a package that is extremely rugged and that is symmetrical about the axis of the die. To avoid shorting between adjacent leads, moats are formed in the leads where they face the die to prevent liquid epoxy or solder from spreading between the leads. Since no central tie bar is required, multiple dice can readily be packaged in a single plastic capsule.

Package for semiconductor die containing symmetrical lead and heat sink

Symmetrical package for semiconductor die

A leadframe for making an electric connection to a semiconductor die contains a plurality of notches which correspond to the edges of the die. Shorts are thereby prevented between the leadframe and electrical elements near the edge of the die, even when the leadframe is bent in the direction of the die to make a surface mount package. Alternatively or additionally, the leads in the leadframe may contain moats which prevent the epoxy or solder used to attach the leadframe to a die from spreading outward and thereby creating electrical shorts with other leads.

Surface mount semiconductor package, die-leadframe combination and leadframe therefor and method of mounting leadframes to surfaces of semiconductor die

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Fremont, CA, United States of America

Allen K Lam