IC Package Mold Locks via Interconnect Holes and Tie Bar Slots
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Solution Overview
Problem
Existing integrated circuit package technologies face challenges in providing cost-effective solutions for thermal, reliability, and structural requirements, particularly due to poor heat dissipation and delamination issues caused by the use of molded plastic epoxy and lead frame designs, which affect performance in demanding environmental conditions.
Innovation Solution
The integrated circuit package system incorporates external interconnects with holes and tie bars featuring slots, which are filled with encapsulation to form mold locks, providing structural reinforcement and improving adhesion, thereby reducing delamination and enhancing performance in moisture sensitivity tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molded plastic epoxy is used for protecting the package, then protection is provided, but heat dissipation property deteriorates leading to device malfunctions
Solution Approach 1:
The package structure is segmented into distinct functional zones: the EMC provides protection in non-critical areas, while the paddle serves as a dedicated thermal management component with enhanced heat dissipation capabilities. This segmentation allows each material to optimize its primary function without compromising the other.
Solution Approach 2:
The package employs a composite structure combining EMC and paddle materials with different thermal properties. The paddle acts as a thermal pathway with higher heat dissipation capability, while the EMC provides environmental protection, creating a composite system that balances protection and thermal management.
2Productivity
If integrated circuit devices are made large and thin, then integration density improves, but susceptibility to warpage increases
Solution Approach 1:
The solution addresses the two-dimensional warpage problem by introducing a third-dimensional reinforcement structure. The raised feature on the paddle creates a vertical dimension that mechanically counters warpage forces, allowing thin, high-density packages to maintain dimensional stability without sacrificing integration density.
3Strength
If lug feature is added to lead design for locking, then locking between lead and mold compound improves, but metal-to-metal space decreases and mold compound flow is disturbed
Solution Approach 1:
Instead of modifying the lead structure with lugs, the invention creates a simplified copy of the locking function through the raised paddle feature. The mold compound is copied into the recess formed by the raised feature, creating a locking mechanism that achieves the same structural interlocking without adding complex lead geometries.
4Productivity
If die area covers more space above the paddle and leads, then integration capacity improves, but delamination problems become more serious or frequent
Solution Approach 1:
The raised feature on the paddle performs a preliminary action by creating a mechanical interlock with the mold compound before the die is mounted. This pre-established locking structure provides a stable foundation that prevents subsequent delamination, even when the die area extensively covers the paddle and lead regions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the reliability and yield of integrated circuit packages by improving moldability, reducing delamination, and increasing metal-to-metal spacing for better encapsulation flow, while also improving performance in moisture sensitivity level (MSL) tests.
Implementation Method 1
molding the external interconnect and the tie bar with the slot and the hole filled
Implementation Method 2
providing structural reinforcement and improving adhesion, thereby reducing delamination
Data Source
AI summary
An integrated circuit package system is provided including forming an external interconnect and a tie bar, forming a lead tip and a lead body of the external interconnect, forming a hole in the external interconnect, forming a slot in the tie bar, connecting an integrated circuit die and the external interconnect, and molding the external interconnect and the tie bar with the slot and the hole filled.