Fusion Quad Flat Package with Concentric Exposed Lead Rows
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Solution Overview
Problem
There is a growing need in high-frequency applications such as cell phones and Bluetooth devices for semiconductor packages with increased functional capacity, particularly in QFP exposed pad packages that incorporate exposed leads and an exposed die pad on the bottom surface, which existing technologies have not adequately addressed.
Innovation Solution
The development of a semiconductor package with a uniquely configured leadframe that maximizes exposed leads, featuring a generally planar die paddle with peripheral edge segments and segregated lead rows, where the die paddle, leads, and semiconductor die are encapsulated by a package body, with the bottom surfaces of the die paddle and leads exposed, utilizing standard low-cost leadframe design techniques and fabrication methods like sawing to electrically isolate leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard QFP package design is used, then manufacturing cost is low, but functional capacity is limited
Solution Approach 1:
The patent introduces a third concentric row of leads in addition to the traditional two rows, expanding the lead arrangement from a two-dimensional pattern to a three-dimensional concentric configuration. This dimensional expansion maximizes the number of exposed leads while maintaining compatibility with standard QFP package formats, thereby increasing functional capacity without proportionally increasing complexity
2Quantity of substance
If more leads are exposed, then functional capacity increases, but manufacturing complexity increases
Solution Approach 1:
The leadframe is segmented into three distinct concentric rows of leads, with each row serving specific functional purposes. This segmentation allows for systematic arrangement of a high number of leads (up to 48 or more) in an organized manner, making the complex leadframe configuration manageable through modular organization rather than a monolithic design
Solution Approach 2:
The concentric row configuration serves multiple functions simultaneously: it maximizes lead count, provides electrical isolation between leads, maintains positional consistency, and accommodates various die sizes. This multi-functional design achieves high lead exposure without proportionally increasing manufacturing complexity
3Reliability
If leads are electrically isolated, then reliability improves, but additional processing steps are required
Solution Approach 1:
The package body encapsulant material automatically provides electrical isolation between the exposed leads and die pad through its inherent insulating properties. This self-service approach eliminates the need for additional dedicated isolation structures or processing steps, as the encapsulation process itself fulfills the electrical isolation requirement while protecting the components
Data Source
AI summary
A semiconductor package which includes a generally planar die paddle defining multiple peripheral edge segments and a plurality of leads which are segregated into at least two concentric rows. Connected to the top surface of the die paddle is at least one semiconductor die which is electrically connected to at least some of the leads of each row. At least portions of the die paddle, the leads, and the semiconductor die are encapsulated by a package body, the bottom surfaces of the die paddle and the leads of at least one row thereof being exposed in a common exterior surface of the package body.