Tiebar-less IC Packaging Design for Void Reduction
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Solution Overview
Problem
Current integrated circuit packaging systems face challenges in miniaturization, cost-effectiveness, and yield improvement due to the need for smaller, thinner components with increased density and reduced voids, which existing solutions have not adequately addressed.
Innovation Solution
The development of a tiebar-less integrated circuit packaging system that includes a die attach pad, lead, internal interconnect, encapsulation, and isolation cover, where the lead and die attach pad have recessed and overhanging portions for improved bonding and a mold filler or coating layer for electrical isolation, eliminating the need for conventional tiebars and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional tiebar-based packaging structures are used, then structural support is provided, but packaging dimensions cannot be sufficiently reduced and voids are formed
Solution Approach 1:
The patent removes the tiebar component from the packaging structure entirely. The lead frame is designed without tiebars, using only the essential lead and die attach pad structures, thereby eliminating the voids that tiebars create while maintaining sufficient structural support for the integrated circuit die.
Solution Approach 2:
The patent applies localized reinforcement at critical areas of the lead frame, specifically at the die attach pad and lead connections, rather than using universal tiebar support. This allows structural integrity to be maintained at stress points while minimizing overall packaging volume in non-critical areas.
2Area of stationary object
If packaging density is increased for miniaturization, then smaller device sizes are achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The lead frame structure serves multiple functions simultaneously: it provides electrical connections through the leads, mechanical support for the die attach pad, and structural stability without requiring separate tiebar components. This multi-functionality reduces manufacturing steps and complexity while achieving high packaging density.
Solution Approach 2:
The lead frame is segmented into distinct functional zones (leads, die attach pad, isolation cover areas) that can be independently optimized and manufactured. This segmentation allows for standardized manufacturing processes that reduce complexity while enabling high-density packaging configurations.
3Volume of stationary object
If tiebars are removed to reduce voids, then packaging volume is reduced, but electrical isolation between lead and die attach pad becomes problematic
Solution Approach 1:
The patent introduces an isolation cover as an intermediary component between the lead and die attach pad. This isolation cover provides the necessary electrical isolation without requiring tiebars, thereby reducing voids while maintaining proper electrical separation between conductive elements.
Solution Approach 2:
The isolation cover is implemented as a simple, thin, disposable-like component that provides temporary electrical isolation during assembly and operation without requiring complex or expensive isolation structures. This approach efficiently solves the isolation problem while minimizing volume.
Data Source
AI summary
A method of manufacture of an integrated circuit packaging system includes: providing a die attach pad integrally connected to a connector portion and a lead; attaching an integrated circuit die to the die attach pad; connecting an internal interconnect to the integrated circuit die and the lead; forming an encapsulation over the integrated circuit die; removing the connector portion to separate the die attach pad and the lead; and forming an isolation cover between the die attach pad and the lead.