Lead Frame Layout With Unequal Leads for Power and Signal Routing
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Solution Overview
Problem
Conventional semiconductor packages with uniformly sized leads face challenges in meeting voltage drop, dynamic ripple, electromagnetic, and thermal requirements due to the limited availability of signal leads when increasing power leads, which is a costly solution.
Innovation Solution
Implementing a lead frame with power leads and signal leads of different sizes, where power leads are thicker and wider than signal leads, to meet IR drop, dynamic ripple, electromagnetic, and thermal requirements while maintaining the same size of the lead frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of power leads is increased to meet voltage drop, dynamic ripple, electromagnetic, and thermal requirements, then the electrical and thermal performance is improved, but the cost increases and fewer signal leads are available
Solution Approach 1:
The patent applies local quality by making power leads thicker and wider than signal leads. Specifically, power leads have a first thickness and first width, while signal leads have a second thickness and second width that are smaller. This localized differentiation allows each lead type to be optimized for its specific function - power leads for current carrying capacity and signal leads for signal integrity - thereby meeting electrical and thermal requirements without uniformly increasing all lead dimensions or cost.
Solution Approach 2:
The patent segments the leads into two distinct categories: power leads and signal leads, with different dimensional characteristics. Power leads are designed with larger cross-sections to handle higher currents and thermal loads, while signal leads are optimized for their respective functions. This segmentation allows the lead frame to meet performance requirements for power delivery without unnecessarily increasing the size or cost of signal leads.
2Reliability
If power leads are made thicker and wider to reduce resistance and meet thermal requirements, then the electrical conductivity and heat dissipation are improved, but the available space in the lead frame is reduced
Solution Approach 1:
The patent implements local quality by assigning different thickness and width dimensions to power leads versus signal leads. Power leads have increased dimensions specifically where needed to reduce resistance and improve heat dissipation, while signal leads maintain smaller dimensions to preserve space. This localized optimization ensures that space constraints are not uniformly violated across all leads, allowing the lead frame to accommodate both large power leads and multiple signal leads within the same footprint.
3Area of stationary object
If signal leads are reduced in size to accommodate larger power leads, then more space is available for power leads, but signal quality may be compromised
Solution Approach 1:
The patent applies local quality by ensuring that signal leads, while smaller than power leads, still have dimensions (second thickness and second width) that are sufficient for their intended signal transmission functions. The power leads have first thickness and first width optimized for power delivery, while signal leads have appropriately sized dimensions for signal integrity. This differentiated approach allows space optimization for power leads without compromising signal lead functionality.
Data Source
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AI summary
A semiconductor package comprises a leadframe with a first lead and a second lead where the first lead has a larger size compared to the second lead. The lead frame further comprises a die attach area on which a die with one or more bond pads of the die is attached and where the first lead and the second lead extend outwardly from the die attach area. The one or more bond pads are associated with the first lead and a plurality of bond wires is arranged between a bond pad and the first lead.