Power Module Substrate Bonding via Deformed Metallic Intermediaries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for manufacturing power module substrates with laminated ceramic and metal layers face issues such as separation and cracking due to thermal expansion differences between ceramic and metal substrates, and dimensional variations during the sintering process.
Innovation Solution
The method involves alternately laminating and bonding ceramic substrates with metal plates using columnar metallic members inserted into penetration holes, where the metallic members are plastically deformed to adjust for dimensional variations and create interspaces to absorb thermal expansion differences, thereby stabilizing the bond between the metal and ceramic substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molten metal is fed and solidified in penetration holes to connect metal plates, then electrical connection between metal plates is achieved, but separation and cracking occur due to thermal expansion differences
Solution Approach 1:
A metallic member is introduced as an intermediary element between the first and second metal plates, filling the penetration hole and providing a compliant connection that accommodates thermal expansion differences. This intermediary absorbs thermal stress through elastic deformation, preventing direct stress transmission between the ceramic substrate and metal plates that would cause cracking and separation.
Solution Approach 2:
The physical state of the metallic member is changed from rigid (when directly bonding metal plates) to elastic/compliant (when filling penetration holes), allowing it to deform elastically under thermal stress. This parameter change in mechanical compliance enables the system to accommodate thermal expansion differences without failure.
2Adaptability or versatility
If ceramic substrates are sintered with penetration holes, then multilayer structure is formed, but dimensional tolerance variation causes unstable bonding
Solution Approach 1:
The metallic member is designed with dimensions that provide a clearance fit within the penetration hole, creating a cushioning effect that absorbs dimensional variations from the sintering process. This beforehand cushioning accommodates the large dimensional tolerances inherent in ceramic sintering without compromising bonding stability.
Solution Approach 2:
The metallic member provides localized compliance specifically at the penetration hole interface, while maintaining rigid structural support elsewhere. This local quality of compliant bonding allows the multilayer structure to accommodate dimensional variations only where needed, without sacrificing overall structural integrity.
3Strength
If metallic members are inserted and brazed to both metal plates, then connection is achieved, but variation in dimensional difference prevents stable bonding
Solution Approach 1:
The metallic member is designed to be elastically deformable rather than rigidly fixed, allowing it to dynamically adjust to dimensional variations during and after assembly. This dynamic compliance enables stable bonding despite variations in the dimensional differences between ceramic substrates and metal plates.
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 approach reduces thermal stress and prevents separation or cracking, resulting in a highly reliable multilayered power module substrate with improved bonding stability over time.
Implementation Method 1
the metallic members are pressurized and plastically deformed so that the metal plates on both sides of the ceramic substrates are bonded through the metallic members
Implementation Method 2
it is possible to absorb the difference in the coefficient of thermal expansion between the metallic member and the ceramic substrate using the interspace even when the metallic member is thermally expanded and shrunk repeatedly due to a temperature cycle
Implementation Method 3
the ceramic substrate is a sintered part, and has a significantly large dimensional tolerance compared to the metallic members due to the influence of shrinkage during sintering
Data Source
AI summary
A method of manufacturing a power module substrate in which a plurality of ceramic substrates and metal plates are alternately laminated, and bonded, and the metal plates on both sides of the ceramic substrates are in a connected state through penetration holes formed in the ceramic substrate, wherein, when the ceramic substrates and the metal plates are laminated, columnar metallic members that are longer than the penetration holes are inserted into the penetration holes in the ceramic substrate, and, when the ceramic substrates and the metal plates are bonded, the metallic members are pressurized and plastically deformed so that the metal plates on both sides of the ceramic substrates are bonded through the metallic members.