Leadframe Panel for Power Packages with Tie Bar Singulation
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Solution Overview
Problem
Conventional IC power package packaging methods are inefficient, leading to wasted molding and leadframe material, restricted size, and the need for custom tooling for singulation, which limits scalability and increases costs.
Innovation Solution
A high-density leadframe panel with a two-dimensional array of device areas and intermediate tie bars, where leads and die attach pads are carried by tie bars, allowing for efficient encapsulation and singulation with reduced material waste, enabling thinner packages and increased heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional individual device area encapsulation and trim-forming methods are used, then IC power packages can be produced, but material waste increases and manufacturing efficiency decreases
Solution Approach 1:
The patent merges multiple device areas onto a single leadframe panel with shared tie bars, combining what were previously separate packaging operations into an integrated structure that enables simultaneous encapsulation and reduces material waste through shared support elements
Solution Approach 2:
The intermediate tie bars serve multiple functions: they provide mechanical support for leads and die attach pads across multiple device areas, enable efficient material utilization, and facilitate the encapsulation process, replacing the need for custom tooling while maintaining packaging effectiveness
2Ease of manufacture
If custom tooling is used for singulation and lead formation, then IC power packages can be produced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the singulation and lead formation operations from the encapsulation process, allowing these operations to be performed separately on already-encapsulated packages, thereby eliminating the need for complex custom tooling that must integrate multiple functions simultaneously
Solution Approach 2:
The manufacturing process is segmented into distinct stages: encapsulation first, then singulation, then lead formation. This segmentation allows each operation to be simplified and performed with standard equipment rather than requiring complex integrated custom tooling
3Area of stationary object
If conventional leadframe structures are used, then IC power packages can be packaged, but package size is restricted and heat dissipation is limited
Solution Approach 1:
The patent extends the die attach pad in the vertical dimension (thickness direction) to create an elongated structure that increases surface area for heat dissipation without increasing the horizontal footprint, thereby improving thermal management while maintaining compact package dimensions
Data Source
AI summary
An improved leadframe panel suitable for use in packaging IC dice for use in power applications is described. The described leadframe panel enables more efficient means of encapsulation and singulation as compared with a conventional power leadframe panel. Additionally, a thin IC power package is described that enables increased package heat dissipation, the use of a larger die attach pad as well as the use of a larger die as compared with conventional power devices.