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Embedded Die Exposed Pad Quad-Flat Packages

IP.com Disclosure Number: IPCOM000239047D
Publication Date: 2014-Oct-03
Document File: 4 page(s) / 85K

Publishing Venue

The IP.com Prior Art Database

Abstract

In this paper we present an embedded die in exposed pad QFP packages where the height difference between the die and the leads is minimized, which allows reduction in wire payout and improvements in wire sweep. The ground ring is also placed at the same plane as the die flag, which can then be held down by vacuum and significantly improve wire bondability. The final down-set to form the exposed pad connection is embedded within the area of the flag, and thus, a larger die size may be used without exceeding lead frame design rules.

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Embedded Die Exposed Pad Quad-Flat Packages

 

Abstract 

In this paper we present an embedded die in exposed pad QFP packages where the height difference between the die and the leads is minimized, which allows reduction in wire payout and improvements in wire sweep.  The ground ring is also placed at the same plane as the die flag, which can then be held down by vacuum and significantly improve wire bondability.  The final down-set to form the exposed pad connection is embedded within the area of the flag, and thus, a larger die size may be used without exceeding lead frame design rules.

Background

Existing exposed pad QFP packages have a very deep down-set to enable the die pad to be exposed after molding.  The deep down-set results in a large difference between the heights of die top and the leads, which increases total wire payout, especially for exposed pad QFP with power bars.  This results in high risk of wire short due to wire sweep.  Existing exposed pad QFP packages also have an isolated ground ring that is on an intermediate plane that cannot be clamped and/or vacuumed by the heater block.  This results in a floating design, which creates difficulties at wire bond process.  Furthermore, the location of the down-set between the isolated ground ring and the die flag increases the total consumed area of the package, which also limits the total die size.

We propose an embedded die in exposed pad QFP packages where the height difference between the die and the...