Dual-Substrate Power Package for Load Dump Thermal Management
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Solution Overview
Problem
Current power device package structures primarily focus on reducing steady-state thermal resistance, leaving transient-state thermal resistance and associated high heat issues unaddressed, which can lead to damage during load dump phenomena in vehicle generators.
Innovation Solution
A power device package structure incorporating a first substrate with high thermal conductivity and a second substrate with greater heat capacity, where the second substrate is positioned under the power device, effectively reducing both steady-state and transient-state thermal resistance by efficiently managing heat generated during transient events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only steady-state thermal resistance is reduced, then steady-state heat dissipation is improved, but transient-state thermal resistance remains high causing damage during load dump events
Solution Approach 1:
The package structure is segmented into two distinct substrates: a first substrate (DBC substrate) for steady-state heat dissipation and a second substrate (CU substrate) for transient-state heat absorption. This segmentation allows each substrate to be optimized for its specific function, resolving the contradiction between improving transient-state reliability and maintaining structural simplicity.
Solution Approach 2:
Different regions of the package structure are assigned different thermal properties: the first substrate has high thermal conductivity for steady-state heat dissipation, while the second substrate has high heat capacity for transient-state heat absorption. This local quality differentiation enables the structure to handle both steady-state and transient thermal conditions effectively without requiring a completely complex redesign.
2Reliability
If a single substrate is used, then the structure is simple, but it cannot simultaneously optimize both steady-state and transient-state thermal resistance
Solution Approach 1:
The patent merges two substrates with complementary thermal characteristics into a unified package structure. The first DBC substrate and second CU substrate are combined through bonding, creating a composite structure that simultaneously provides steady-state heat dissipation capability and transient-state heat absorption capability, thereby improving junction temperature control without requiring excessively complex configuration.
Solution Approach 2:
The package structure employs composite material principles by combining different substrate materials (DBC and CU) with distinct thermal properties. This composite approach allows the structure to leverage the high thermal conductivity of the first substrate for steady-state operation and the high heat capacity of the second substrate for transient-state protection, achieving dual optimization without excessive complexity.
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 proposed structure significantly reduces junction temperature during load dump events, protecting the power device from damage by effectively managing both steady-state and transient-state thermal resistance, as demonstrated by experimental results showing lower temperature rises compared to comparative examples.
Implementation Method 1
A heat conductivity of the first substrate is greater than 200 Wm−1K−1
Implementation Method 2
a heat capacity of the second substrate is greater than that of the first substrate
Data Source
AI summary
A power device package structure including a first substrate, a second substrate, at least one power device, and a package is provided. A heat conductivity of the first substrate is greater than 200 Wm−1K−1. The power device is disposed on the first substrate, and the second substrate is disposed under the first substrate. A heat capacity of the second substrate is greater than that of the first substrate. The package encapsulates the first substrate, the second substrate, and the power device.