Comb-Like Leadframe for Power Package Current Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current package structures for planar power components face challenges in achieving uniform and stable current density and voltage due to thin metal structures that limit current carrying capacity and introduce voltage differences.
Innovation Solution
A package structure with a comb-like leadframe is designed, featuring extended parts protruding from a base part, which increases the total cross-sectional area for current conduction, reducing resistance and voltage differences, and is supported by metal or insulating protrusions to prevent deformation during packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin metal structure is used in the chip for current collection, then the chip size can be reduced, but the current carrying capacity is limited and voltage differences occur
Solution Approach 1:
The leadframe structure transitions from a planar two-dimensional configuration to a three-dimensional comb-like structure with extended parts protruding from the base part. This dimensional change increases the cross-sectional area for current conduction without proportionally increasing the chip footprint, thereby improving current carrying capacity while maintaining compact chip size.
Solution Approach 2:
The leadframe is segmented into a base part and multiple extended parts that alternate with each other. This segmentation creates multiple current conduction paths through the extended parts, distributing the current flow and reducing voltage differences across the metal structure, thus improving reliability without requiring a single large thick metal layer.
2Reliability
If the metal structure thickness is increased to improve current carrying capacity, then voltage differences are reduced, but the chip size and package volume increase
Solution Approach 1:
Instead of increasing metal layer thickness in the vertical dimension, the invention extends the current conduction path horizontally through the comb-like extended parts. This approach increases the effective cross-sectional area for current flow without proportionally increasing the overall package volume, maintaining voltage uniformity while controlling package size.
Solution Approach 2:
The base part and extended parts are merged into a unified comb-like leadframe structure that works together to distribute current. The alternating arrangement of extended parts from opposite sides creates multiple parallel current paths that collectively improve voltage uniformity across the chip without requiring excessive material volume.
3Reliability
If a comb-like leadframe structure is used to increase current carrying capacity, then uniform current density is achieved, but the structure complexity increases
Solution Approach 1:
The leadframe is divided into a base part and multiple extended parts that are relatively simple in shape but collectively create the desired current distribution. This segmentation into modular elements simplifies the manufacturing process compared to creating a single complex thick metal structure, while achieving uniform current density through the alternating extended parts.
Solution Approach 2:
The comb-like leadframe structure serves multiple functions simultaneously: it acts as the current collection structure, provides mechanical support for the chip, and enables uniform current distribution. This multi-functionality reduces the need for additional separate components, thereby managing overall device complexity despite the enhanced structural configuration.
4Stability of the object's composition
If protrusions are added to prevent deformation during packaging, then structural stability is improved, but the manufacturing complexity increases
Solution Approach 1:
Protrusions are pre-formed on the extended parts of the leadframe before the packaging process. These protrusions serve as preliminary structural reinforcements that prevent deformation during subsequent packaging operations. By preparing these features in advance during leadframe fabrication, the need for complex post-packaging adjustments or additional support structures is eliminated.
Solution Approach 2:
The protrusions are integrated into the extended parts of the comb-like leadframe as a unified structure rather than being added as separate components. This merging of the protrusion feature with the existing leadframe geometry allows for simultaneous formation during the same manufacturing process, reducing overall manufacturing complexity despite the enhanced structural stability provided by the protrusions.
Data Source
AI summary
A package structure is provided. The package structure includes a leadframe including a first portion and a second portion. The first portion includes a first base part and a plurality of first extended parts connected to the first base part. The second portion includes a second base part and a plurality of second extended parts connected to the second base part. The first extended parts and the second extended parts are arranged in such a way that they alternate with each other. In the package structure, a chip is disposed on a part of the first extended parts of the first portion and the second extended parts of the second portion of the leadframe. The package structure further includes a plurality of protrusions, opposite to the chip, disposed on the first extended parts and the second extended parts.