Power Module Spacer Brazing for Heat Dissipation and Vibration Resistance
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Solution Overview
Problem
Existing power modules face challenges in achieving high strength and heat dissipation characteristics, particularly in double-sided cooling power modules used in electric vehicles, where high voltage leads to heat generation and vibration, necessitating improved bonding and heat management.
Innovation Solution
A power module design featuring a first substrate with a semiconductor chip mounted on its upper surface, a spacer bonded to the substrate to define a separation distance, and a brazing bonding layer using AgCu with optional Ti, integrated with a ceramic substrate and metal layer, and a bonding layer of solder or Ag paste for enhanced bonding and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a double-sided cooling power module is used to improve heat dissipation, then heat dissipation performance is improved, but bonding reliability deteriorates due to electrode peeling under high voltage and vibration
Solution Approach 1:
A Ti layer is introduced as an intermediary between the AgCu brazing bonding layer and the ceramic substrate. The Ti layer acts as a diffusion barrier and bonding promoter, preventing direct contact between AgCu and the ceramic substrate, thereby eliminating electrode peeling while maintaining effective thermal conduction through the brazing layer.
Solution Approach 2:
The bonding structure uses a composite material system consisting of ceramic substrate + Ti layer + AgCu brazing bonding layer. This multi-layer composite structure combines the high heat dissipation capability of AgCu with the protective and bonding-enhancing properties of Ti, resolving the contradiction between thermal performance and bonding reliability.
2Strength
If high strength bonding is achieved to resist vibration, then bonding strength is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The Ti layer is applied locally at the interface between the AgCu brazing bonding layer and the ceramic substrate, providing localized bonding enhancement and peeling prevention only where needed, while the bulk AgCu layer maintains its superior thermal conduction properties for heat dissipation.
Solution Approach 2:
The composite structure of Ti + AgCu brazing bonding layer provides both high bonding strength (through Ti's interface reinforcement) and high heat dissipation capability (through AgCu's thermal conductivity), resolving the trade-off between strength and heat dissipation.
3Temperature
If a spacer is added to define separation distance for heat management, then heat dissipation is improved, but device complexity increases
Solution Approach 1:
The Ti layer serves multiple functions simultaneously: it acts as a diffusion barrier preventing AgCu from contacting the ceramic substrate, promotes bonding between layers, and contributes to thermal conduction. This multi-functionality reduces the need for additional components, offsetting the complexity introduced by the spacer.
Solution Approach 2:
The spacer is integrated into the existing substrate structure, and the Ti layer is combined with the AgCu brazing bonding layer to form a unified multi-layer bonding structure. This merging approach minimizes the addition of separate components, reducing overall device complexity while maintaining heat management functionality.
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 prevents electrode peeling, enhances heat dissipation, maintains strong bonding against vibrations, and improves the overall performance of the power module by using an active metal brazing substrate and a spacer made of insulating materials.
Implementation Method 1
a brazing bonding layer configured to bond the spacer to the first substrate
Implementation Method 2
performing heat treatment on the brazing bonding layer and brazing and bonding the spacer to the first substrate
Implementation Method 3
The first substrate may include a ceramic substrate and a metal layer brazed and bonded to at least one surface of the ceramic substrate
Implementation Method 4
the bonding layer may be made of solder or an Ag paste
Data Source
AI summary
The present invention relates to a power module and a method for manufacturing same, in which an insulating spacer is disposed between two upper and lower substrates to thus efficiently dissipate the heat generated from a semiconductor chip mounted between the substrates, and prevent bending deformation due to heat. In addition, since the spacer made of an insulating material is integrated with the substrates by brazing bonding, the bonding strength is improved, thereby maintaining strong bonding even against vibration, etc.