Lead Frame Layout With Unequal Leads for IR Drop and Thermal Control

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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 power leads are increased, which is a costly solution.

Innovation Solution

Employing a lead frame with power leads that are thicker and wider than signal leads, along with multiple bond wires, to meet IR drop, dynamic ripple, and thermal requirements while maintaining sufficient signal leads, and incorporating a slot in the power lead to reduce inductance and thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of power leads is increased to meet voltage drop, dynamic ripple, and thermal requirements, then the electrical and thermal performance is improved, but the number of available signal leads decreases and manufacturing cost increases

Engineering Contradiction:

Improveelectrical and thermal performanceVSAvoidlead frame structure

Core Design Contradiction:

ReliabilityVSDevice complexity

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 thermal conduction, signal leads for signal transmission - thereby meeting electrical and thermal requirements without unnecessarily increasing overall device complexity or reducing signal lead availability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the leads by specifying different thickness and width dimensions for power leads versus signal leads. The power leads have increased thickness and width parameters compared to signal leads, which directly addresses the voltage drop, dynamic ripple, and thermal requirements through parameter optimization rather than simply increasing the number of leads

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If lead width is reduced to maintain more signal leads, then the number of signal leads increases, but the electrical performance and current carrying capacity deteriorate

Engineering Contradiction:

Improvenumber of signal leadsVSAvoidelectrical performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by differentiating lead dimensions based on functional requirements. Signal leads maintain sufficient width and thickness to meet electrical performance requirements while being narrower than power leads. This localized optimization ensures each lead type has appropriate dimensions for its specific electrical characteristics, maintaining signal integrity without unnecessarily reducing the number of signal leads

Inventive Principle:

Principle #3Local quality

3Reliability

If a slot is added to the power lead to reduce inductance and thermal expansion, then the electrical and thermal stability is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveelectrical and thermal stabilityVSAvoidlead frame fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the power lead by introducing a slot that extends from an outer portion toward an inner portion. This slot modifies the physical structure to reduce inductance and accommodate thermal expansion, thereby improving electrical and thermal stability. The slot dimensions and positioning are optimized to achieve the desired electrical and thermal performance while considering manufacturability

Inventive Principle:

Principle #35Parameter changes

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 addresses voltage drop, dynamic ripple, and thermal issues while preserving signal quality and reducing resistance and impedance, enhancing the performance of semiconductor packages.

Implementation Method 1

the first lead has a larger size than the second lead, the first lead has one or more of a larger width and thickness than the second lead... to meet IR drop, dynamic ripple, and thermal requirements while preserving signal quality and reducing resistance and impedance

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

incorporating a slot in the power lead to reduce inductance and thermal expansion

Methodology Applied

Scientific EffectThermal Expansion: Thermal Expansion

Data Source

PatentUS20260011626A1Semiconductor package having lead frame with leads of different sizes and method of manufacture

Publication Date: 2026.01.08 NXP BV

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.