Lead-Frame Package Thermal Surface for Dual-Path Heat Dissipation

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Solution Overview

Problem

Existing lead-frame packages suffer from inadequate heat dissipation, primarily relying on a single path through the thermal die pad to the PCB, which limits the amount and rate of heat dissipation, and are prone to delamination and voids in the die attach substance.

Innovation Solution

The introduction of a thermal dissipation surface on the top surface of the lead-frame package, coupled with thermally conductive paths and finned protrusions, provides additional heat dissipation paths, enhancing heat transfer away from the semiconductor IC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat dissipation relies on a single path through the thermal die pad to the PCB, then the structure is simple, but the heat dissipation efficiency is insufficient

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidthermal dissipation structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The thermal dissipation function is segmented into multiple independent paths: one path through the die pad to the PCB, and another path through the thermal dissipation surface to the external environment. This segmentation allows heat to be dissipated through parallel channels, improving overall heat dissipation efficiency without creating a single point of failure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a vertical dimension to heat dissipation by introducing a thermal dissipation surface that extends heat dissipation from the traditional planar PCB interface into the third dimension (vertical direction). This allows heat to escape through the top surface of the package, creating a new thermal pathway that complements the bottom-side PCB attachment path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the die attach substance is used for thermal conduction, then electrical insulation is provided, but delamination and voids occur reducing reliability

Engineering Contradiction:
Improvethermal path reliabilityVSAvoidthermal management structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thermal dissipation surface acts as an intermediary thermal management component that provides an alternative heat pathway. Instead of relying solely on the die attach substance to conduct heat to the PCB, the thermal dissipation surface serves as an intermediate structure that directly conducts heat from the semiconductor IC to the external environment, bypassing the reliability issues of the die attach interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the thermal conduction parameters by introducing a dedicated thermal dissipation surface with optimized thermal conductivity properties. This surface is specifically designed and configured to provide superior thermal conduction compared to the die attach substance, altering the thermal management parameters of the overall package structure.

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

This configuration significantly improves heat dissipation from the semiconductor IC, increasing performance and reliability, especially in harsh environments.

Implementation Method 1

a thermal dissipation surface at the second surface of the lead-frame package thermally coupled to the semiconductor IC. In some embodiments, the thermal dissipation surface provides a thermal dissipation path from the semiconductor IC to the second surface of the lead-frame package

Methodology Applied
Scientific EffectHeat dissipation: Conduction (thermal)

Implementation Method 2

a thermally conductive semiconductor IC path from the semiconductor IC to the second surface of the lead-frame package

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a plurality of finned protrusions extending from the thermal dissipation surface

Methodology Applied
Scientific EffectHeat dissipation: Convection

Data Source

PatentEP4648103A1Lead-frame package with improved heat dissipation
Publication Date: 2025.11.12 STMICROELECTRONICS INT NV
  • EP4648103A1 patent drawingFigure 1
  • EP4648103A1 patent drawingFigure 2
  • EP4648103A1 patent drawingFigure 3

AI summary

An example lead-frame package, a method of manufacturing a lead-frame package, and an electrical system comprising a lead-frame package with improved heat dissipation are provided. An example lead-frame package with improved heat dissipation includes a first surface and a second surface opposite the first surface. The example lead-frame package further includes a semiconductor integrated circuit (IC) thermally coupled to a die pad, the die pad forming a portion of the first surface of the lead-frame package. The example lead-frame package further includes a thermal dissipation surface at the second surface of the lead-frame package thermally coupled to the semiconductor IC. The thermal dissipation surface provides a thermal dissipation path from the semiconductor IC to the second surface of the lead-frame package.