Semiconductor Package With Depression Lead Tips For Wire Separation
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Solution Overview
Problem
Dual row leadframes in semiconductor packages tend to experience wire crossing and wire sweep issues, leading to electrical shorts and package failures, which existing solutions have not adequately addressed.
Innovation Solution
A semiconductor package system is designed with a substrate having a die attach paddle surrounded by a first plurality of leads and a second plurality of leads, where the second leads have depression lead tips to maintain greater wire separation and reduce the likelihood of electrical shorts and wire sweep, using low loop wire-bonding techniques and encapsulation with a molding compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dual row leadframes are used to provide additional leads, then the number of leads increases, but wire crossing and wire sweep issues occur leading to electrical shorts
Solution Approach 1:
The patent applies local quality by creating depression lead tips at specific locations where wires are most likely to cross or sweep. Instead of modifying the entire leadframe structure, only the tip regions of certain leads are depressed, creating localized wire separation zones precisely where needed to prevent electrical shorts while maintaining the dual row configuration for high lead density.
Solution Approach 2:
The patent introduces a vertical dimension to the lead tips by depressing them inward to form cavities. This transforms the traditionally flat, two-dimensional lead tip surface into a three-dimensional structure with depth, creating additional spatial separation for wires in the vertical dimension and preventing wire crossing and sweep issues.
2Reliability
If lead tips are depressed to maintain wire separation, then wire crossing is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent changes the geometric parameter of the lead tips by depressing them to a controlled depth. This parameter modification creates the necessary wire separation while maintaining compatibility with existing manufacturing processes. The depression depth is optimized to provide sufficient wire separation without excessive complexity in the leadframe structure.
3Productivity
If more leads are added in dual row configuration, then packaging density increases, but wire sweep failures increase
Solution Approach 1:
The patent addresses wire sweep prevention by applying local quality modifications only to specific lead tips where wire sweep is most likely to occur. By depressing only the necessary lead tips rather than redesigning the entire leadframe, the patent maintains high packaging density while locally preventing wire sweep failures at critical locations.
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
The solution effectively reduces the occurrence of electrical shorts and wire sweep, enhancing the reliability and performance of semiconductor packages by maintaining greater wire separation and providing a robust encapsulation.
Implementation Method 1
a second plurality of leads around the die attach paddle interleaved with the first plurality of leads, at least some of the second plurality of leads having a plurality of depression lead tips
Implementation Method 2
The die is wire bonded to the first plurality of leads and the second plurality of leads
Implementation Method 3
The die is encapsulated
Data Source
AI summary
A semiconductor package system is provided. A substrate having a die attach paddle is provided. A first plurality of leads is provided around the die attach paddle having a first plurality of lead tips. A second plurality of leads is provided around the die attach paddle interleaved with the first plurality of leads, at least some of the second plurality of leads having a plurality of depression lead tips. A first die is attached to the die attach paddle. The die is wire bonded to the first plurality of leads and the second plurality of leads. The die is encapsulated.