Sinter Paste Joining for Aluminium Power Electronics
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Solution Overview
Problem
Current methods for joining a copper-coated ceramic plate to an aluminium body are costly and complex due to stable oxide layers on the aluminium, which prevent direct soldering or sintering, and existing alternatives either reduce thermal conductivity or increase costs.
Innovation Solution
A method involving a plate-like aluminium body with a copper-coated base plate and pre-treating the joining region to remove oxide layers, followed by application of a sinter paste with copper or silver particles for a pressureless and heat-activated bonding process, eliminating the need for additional connection layers and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nickel plate is used as an intermediate layer between the copper-coated ceramic plate and the aluminium body, then the joining is enabled, but the thermal conductivity is reduced and costs increase
Solution Approach 1:
The patent uses a thin aluminium oxide layer (formed by anodization) as an intermediary between the aluminium body and copper-coated ceramic plate. This natural oxide layer, when made sufficiently thin through controlled anodization, allows thermal conduction while enabling the joining process, replacing the nickel intermediate layer that blocks heat flow.
Solution Approach 2:
The patent changes the thickness parameter of the aluminium oxide layer through controlled anodization parameters (voltage, time, electrolyte composition) to optimize thermal conductivity. By controlling the oxide layer thickness to be in the range of micrometers, thermal resistance is minimized while maintaining joining capability.
2Ease of manufacture
If a nickel plate is used as an intermediate layer between the copper-coated ceramic plate and the aluminium body, then the joining is enabled, but the costs increase
Solution Approach 1:
The patent replaces expensive nickel plates with a thin aluminium oxide layer formed in-situ on the aluminium body surface. This eliminates the need for separate nickel intermediate layers, reducing material costs and simplifying the manufacturing process while maintaining joining capability.
Solution Approach 2:
The aluminium oxide layer serves as a cost-effective intermediary that enables joining without requiring expensive nickel or silver materials. The oxide layer is formed directly on the aluminium body through anodization, eliminating the need for additional expensive intermediate components.
3Loss of energy
If a copper plate is used instead of a nickel plate to connect with the aluminium body, then thermal conductivity is maintained, but the direct joining becomes very laborious and requires additional facilities
Solution Approach 1:
The patent performs preliminary anodization of the aluminium body surface to create a controlled aluminium oxide layer before joining. This preliminary action prepares the surface to accept the copper-coated ceramic plate, eliminating the need for complex direct joining facilities and reducing process complexity.
Solution Approach 2:
The patent changes the surface state of the aluminium body through anodization, creating a receptive oxide layer that facilitates joining. This parameter change (surface oxidation) simplifies the joining process and eliminates the need for additional complex facilities required for direct copper-aluminium joining.
4Device complexity
If the copper-coated ceramic plate is directly connected with the aluminium body without pre-treatment, then the process is simplified, but the stable oxide layers prevent joining
Solution Approach 1:
The patent applies preliminary anodization treatment to the aluminium body surface to create a controlled aluminium oxide layer that enables joining. This preliminary action transforms the naturally resistant oxide layer into a joining-friendly surface, allowing direct connection without complex additional steps.
Solution Approach 2:
The patent changes the properties of the aluminium oxide layer through controlled anodization parameters (thickness, porosity, structure) to make it joining-compatible. By controlling the oxide layer formation, the naturally resistant surface is transformed into a receptive joining surface.
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 method achieves a cost-effective, simplified, and thermally efficient joining of the aluminium body and copper-coated ceramic plate, reducing the number of required layers and facilities, while maintaining a strong and heat-transferring connection.
Implementation Method 1
application of a sinter paste with copper or silver particles for a pressureless and heat-activated bonding process
Implementation Method 2
heat which is generated in the electronic components is transported toward the exterior via the copper body
Data Source
AI summary
A method for producing an electronic arrangement includes providing an aluminium body and a power electronic unit. The power electronic unit includes a base plate and an electronic component. The method includes pre-treating a joining region of a main surface of the aluminium body; coating the pre-treated joining region with a sinter paste including at least one of copper particles and silver particles; positioning the power electronic unit with a second side of the base plate on the main surface of the aluminium body; joining the power electronic unit and the aluminium body in the joining region with supply of heat, wherein the aluminium body and the power electronic unit are connected via the sinter paste in a materially bonded and heat-transferring manner.