Exposed Common Electrode Bars for QFP Inductance Reduction
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Solution Overview
Problem
High-speed and high-performance semiconductor devices require more signal processing terminals, leading to fabrication difficulties in exposed-pad quad flat packages, while ball grid array packaging is not cost-effective and complicated to fabricate.
Innovation Solution
The electronic package design includes a die pad with surrounding leads and common electrode bars that are partially encapsulated by a molding compound, allowing the bottom surfaces of the die pad and common electrode bars to be exposed, with the common electrode bars serving as power or ground pads to reduce the number of leads needed for signal processing and enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more signal processing terminals are added to meet high-speed operation requirements, then device performance is improved, but fabrication difficulty increases
Solution Approach 1:
The patent introduces common electrode bars that extend in a dimensional direction parallel to the die pad surface, rather than only using leads perpendicular to the die pad. This dimensional change allows multiple signal terminals to be accommodated along the length of the electrode bars, increasing terminal count without proportionally increasing fabrication complexity.
Solution Approach 2:
The common electrode bars serve multiple functions: they provide common electrical connections for multiple signal terminals, act as structural support elements, and facilitate heat dissipation. This multi-functionality reduces the overall complexity of the package structure while accommodating high terminal counts.
2Temperature
If exposed-pad QFP is used for heat dissipation, then thermal management is improved, but the number of leads required increases fabrication complexity
Solution Approach 1:
The patent merges the electrical connection function and thermal management function into integrated common electrode bars. These bars simultaneously serve as electrical conduits for multiple signals and as thermal pathways from the die pad, reducing the need for separate dedicated thermal management structures and simplifying the overall package design.
Solution Approach 2:
The common electrode bars are designed to perform multiple functions: providing common electrical connections for signal terminals, structural support for the package, and thermal conduction pathways. This multi-functionality reduces package complexity while achieving effective heat dissipation.
3Quantity of substance
If BGA packaging is used to accommodate more terminals, then terminal capacity is improved, but manufacturing cost and complexity increase
Solution Approach 1:
Instead of using a grid array configuration (BGA) that requires complex three-dimensional positioning, the patent arranges terminals along linear common electrode bars that extend parallel to the die pad surface. This linear arrangement along one dimension simplifies the manufacturing process while still accommodating multiple terminals, avoiding the complexity of BGA ball placement.
Solution Approach 2:
The patent uses a simplified planar configuration that copies the successful exposed-pad QFP layout approach but extends it with additional common electrode bars to accommodate more terminals. This maintains the cost-effective manufacturing process of traditional QFP while increasing terminal capacity, avoiding the need to adopt expensive BGA processes.
Data Source
AI summary
An electronic package is provided. The electronic package comprises a die pad having a die attached thereon. A plurality of leads surrounds the die pad and spaced therefrom to define a ring gap therebetween. At least one first common electrode bar is in the ring gap and substantially coplanar to the die pad, in which at least one of the plurality of leads extends to the first common electrode bar. A molding compound partially encapsulates the die pad and the first common electrode bar, such that the bottom surfaces of the die pad and the first common electrode bar are exposed. A length of the first common electrode bar is substantially equal to a predetermined distance between two pads among a plurality of power or ground pads on a side of the die facing the first common electrode bar. An electronic device with the electronic package is also disclosed.