QFN Package Corner Pins Increase I/O Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Quad-Flat No-Leads (QFN) packaging solutions are limited in accommodating an increasing number of input/output (I/O) terminals, typically allowing less than 100 leads in single-row and less than 165 leads in dual-row designs, leading to the undesirable consequence of larger, heavier, and costlier semiconductor packages when trying to increase terminal count.
Innovation Solution
The addition of corner pins at the QFN package, enabled by converting electrically non-functional tie bars into lead fingers or corner pins, which can increase the pin count by 10-33% without increasing package size, thickness, or weight, by fabricating leadframes with additional pins at the corners in diagonal or parallel orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of I/O terminals is increased in conventional QFN packages, then the terminal count is improved, but the package body size, thickness, and weight increase
Solution Approach 1:
The patent transitions from conventional single-row or dual-row perimeter terminal arrangements to a four-row configuration that utilizes both perimeter and corner positions. This dimensional reorganization of terminal placement allows significantly increased terminal count (up to 40 terminals in a 6x6 mm package) without increasing package body size, as terminals are distributed across multiple spatial dimensions including corner positions that were previously unused for electrical connections
2Quantity of substance
If the number of I/O terminals is increased in conventional QFN packages, then the terminal count is improved, but the package weight increases
Solution Approach 1:
By organizing terminals in a four-row configuration that includes corner positions, the patent achieves higher terminal density within the same package footprint. This dimensional reorganization eliminates the need for additional package material or larger structure, thereby increasing terminal count without increasing package weight
3Quantity of substance
If the number of I/O terminals is increased in conventional QFN packages, then the terminal count is improved, but the manufacturing cost increases
Solution Approach 1:
The four-row terminal configuration with corner terminals utilizes the existing package structure more efficiently, distributing terminals across perimeter and corner positions. This approach achieves higher terminal counts using standard manufacturing processes without requiring additional materials or complex assembly steps, thereby avoiding increased manufacturing costs
4Quantity of substance
If the package body size is increased to accommodate more terminals, then the terminal count is improved, but the lead inductance increases
Solution Approach 1:
The patent maintains a compact package body size by utilizing corner positions and a four-row configuration, which shortens the distance between terminals and the die paddle. This dimensional reorganization reduces lead length and consequently minimizes lead inductance, achieving high terminal count without the harmful effect of increased inductance that would result from larger package size
Data Source
AI summary
There are provided semiconductor packages having corner pins and methods for their fabrication. Such a semiconductor package includes a leadframe and a die paddle, the leadframe having first and second edge sides meeting to form a first corner. The semiconductor package also includes edge pins arrayed substantially parallel to the first edge side and edge pins arrayed substantially parallel to the second edge side. In addition, the semiconductor package includes a first corner pin situated at the first corner, the first corner pin being electrically isolated from the die paddle.