Lead Frame IPM Package Layout for Lower Cost Heat Dissipation

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Solution Overview

Problem

Conventional Intelligent Power Module (IPM) packages face high costs due to the use of expensive Direct Bond Copper (DBC) substrates for heat dissipation, and lead frame designs lead to uneven lead distribution and mold compound overflow issues.

Innovation Solution

The package design relocates cooperation device dies to the lead frame, reducing the size of the DBC substrate and improving lead frame distribution, while maintaining heat dissipation through a multi-layer substrate and lead frame configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If expensive DBC substrates are used for mounting power-side devices, then heat dissipation performance is improved, but packaging cost increases significantly

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidpackaging cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces expensive DBC substrates with a cost-effective lead frame structure that uses standard PCB substrates. The lead frame serves as both the mechanical support and electrical connection medium, eliminating the need for costly DBC substrates while maintaining adequate heat dissipation through optimized lead frame design and thermal vias in the PCB substrate.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The lead frame is designed to perform multiple functions simultaneously: providing mechanical support for mounting power and cooperation devices, establishing electrical connections between devices, and facilitating heat dissipation through its metallic structure and thermal pathways to the PCB substrate. This multi-functional design eliminates the need for separate expensive DBC substrates.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If lead sizes are designed to ensure soldering strength, then soldering reliability is improved, but lead area increases and lead distribution becomes uneven

Engineering Contradiction:

Improvesoldering strengthVSAvoidlead area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent optimizes lead parameters including size, shape, and distribution pattern to achieve adequate soldering strength with reduced lead area. The lead frame design incorporates uniformly distributed leads of optimized dimensions that balance mechanical strength requirements with space efficiency, preventing mold compound overflow while ensuring reliable solder connections.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The lead frame design applies different lead configurations in different regions: power-side leads are designed with specific dimensions for high-current connections, while cooperation device leads are sized appropriately for lower-power connections. This localized optimization ensures each lead has sufficient strength for its specific application while minimizing overall lead area and achieving uniform distribution.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If DBC layout constraints are followed, then device mounting is enabled, but lead distribution becomes uneven causing mold compound overflow

Engineering Contradiction:

Improvedevice mounting capabilityVSAvoidmold compound overflow prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Instead of conforming to traditional DBC layout constraints that cause uneven lead distribution, the patent inverts the approach by designing the lead frame layout first with uniform lead distribution, then mounting devices according to the lead frame configuration. This reverse design methodology ensures even lead distribution and prevents mold compound overflow while still enabling proper device mounting and electrical connections.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP4579732A1Package, manufacturing method thereof and electrical system

Publication Date: 2025.07.02 SHENZHEN STS MICROELECTRONICS CO LTD

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AI summary

The present disclosure relates to package, manufacturing method, and electrical system. The package comprises: a mounting substrate with at least one power die having a power device and attached to a first surface of the mounting substrate; and a lead frame comprising a first die attachment portion and at least one first lead, wherein at least one cooperation device die having a cooperation device for cooperating with the power device is attached to the first die attachment portion, and wherein during a normal operation an amount of heat generated by the cooperation device is less than an amount of heat generated by the power device, wherein the at least one first lead is coupled to the first surface of the mounting substrate to be electrically coupled to the power die.