Semiconductor Leadframe with Segmented Lands for High I/O Density
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Solution Overview
Problem
Conventional semiconductor devices have limitations in providing increased I/O capacity with reduced size and weight, as existing leadframe structures fail to meet the demands of high-frequency applications and consumer electronics.
Innovation Solution
A semiconductor device with a leadframe featuring a combination of leads and lands arranged in a prescribed manner, where the lands are exposed within the package body, fabricated using standard forming techniques such as sawing, punching, or etching to electrically isolate leads, enhancing electrical connectivity and mechanical interlock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional leadframe structures are used, then manufacturing simplicity is maintained, but I/O capacity is limited and size cannot be reduced
Solution Approach 1:
The leadframe structure is segmented into distinct leads and lands components. The lands are separated from the leads through material removal processes, creating discrete connection points that increase I/O capacity while maintaining manufacturing feasibility through standardized segmentation techniques
Solution Approach 2:
The invention transitions from traditional two-dimensional lead arrangements to a three-dimensional configuration by exposing lands within the package body. This vertical integration of connection points (leads extending externally and lands exposed internally) increases I/O capacity without proportionally increasing the package footprint
2Reliability
If leadframe structure is simplified, then ease of manufacture is maintained, but electrical performance and connectivity are insufficient for high-frequency applications
Solution Approach 1:
Material removal processes (sawing, punching, etching) are performed during the fabrication stage to pre-isolate leads and create lands before final assembly. This preliminary structuring ensures optimal electrical performance for high-frequency applications while maintaining ease of manufacture by integrating isolation steps into the existing fabrication workflow
Solution Approach 2:
Different regions of the leadframe are given different properties: leads are designed for external connection with specific electrical characteristics, while lands are exposed within the package body with different geometries and electrical properties. This local differentiation optimizes electrical performance for high-frequency applications while using standard fabrication techniques
3Volume of moving object
If package size is reduced, then weight and space are decreased, but I/O capacity and electrical isolation become more difficult to achieve
Solution Approach 1:
The lands are nested within the package body interior, with leads extending from the internal land structure to external connection points. This nested arrangement allows multiple connection points (increased I/O capacity) to be packed into a smaller volume by utilizing both internal and external spaces efficiently
Solution Approach 2:
Connection points are distributed across multiple dimensions: lands are positioned within the package body volume while leads extend to the external surface. This three-dimensional distribution of I/O points increases capacity without increasing the two-dimensional footprint, enabling size reduction while maintaining I/O capacity
4Ease of operation
If lands are exposed within package body, then integration with PCB is improved, but protection from environment may be compromised
Solution Approach 1:
The package body encapsulant material forms a protective shell that covers and seals the exposed lands within the package interior. This encapsulation provides environmental protection (moisture barrier) while still allowing the lands to be accessible for PCB integration, as the encapsulant can be designed with appropriate opening configurations or the lands can be exposed through controlled portions of the encapsulant
Data Source
AI summary
A semiconductor device includes a die pad, a plurality of first lands each having a first land first top recessed portion disposed on a first land first end distal to the die pad, and a plurality of second lands each having a second land first bottom recessed portion disposed on a second land first end distal to the die pad. A semiconductor die is electrically connected to the first and second lands. A package body, which defines a bottom surface and a side surface, at least partially encapsulating the first and second lands and the semiconductor die such that at least portions of the first and second lands are exposed in and substantially flush with the bottom surface of the package body.