Insulation Circuit Substrate Bonding With Curved Press Boards
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Solution Overview
Problem
The existing methods for manufacturing power module substrate boards with heat sinks face challenges in achieving uniform bonding across the ceramic substrate board, leading to bonding defects, particularly at the inner edge parts where the load is biased towards the outside, resulting in insufficient intermetallic compound formation and potential separation of circuit layers.
Innovation Solution
A method involving the use of support boards with convex curved surfaces to evenly distribute pressure during solid phase diffusion bonding, ensuring adequate load on both the outer and inner edge parts of the copper circuit layers, with a preferred curvature radius between 8000 mm and 60000 mm, and utilizing carbon material sheets to prevent adhesion and achieve uniform pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If pressing boards are used to apply load during bonding, then the bonding process can be performed, but the load is biased towards the outside of the circuit layer and insufficient at the inside peripheral edge parts
Solution Approach 1:
The pressing board is designed with a convex curved surface instead of a flat surface. This curvature allows the pressing board to contact multiple copper boards simultaneously and distribute the pressing load more uniformly across the entire bonding surface, including the previously under-loaded inside peripheral edge parts. The convex shape naturally transitions the force from concentrated at outer edges to distributed across the full area.
2Device complexity
If guide posts are arranged outside the ceramic substrate board, then the structure is simple, but the load cannot be effectively applied to the inside of the laminate
Solution Approach 1:
By giving the pressing board a convex curved surface, the system achieves effective internal load application without adding complex guide post arrangements inside the laminate. The curved surface geometry inherently enables the pressing board to bridge across multiple copper boards and transmit force uniformly to internal regions.
3Adaptability or versatility
If the circuit layer is separated into multiple parts, then circuit functionality is improved, but bonding defects occur easily at the inner edge parts facing the space between adjacent copper boards
Solution Approach 1:
The convex curved surface of the pressing board ensures that even when circuit layers are separated into multiple parts with spaces between adjacent copper boards, the load is uniformly distributed across all bonding interfaces. This prevents the formation of bonding defects at the inner edge parts that would otherwise be vulnerable due to reduced pressure in separated configurations.
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 prevents bonding defects by ensuring uniform load distribution, resulting in sufficient intermetallic compound layer formation and robust bonding across the substrate board, even at the inner edge parts between adjacent copper circuit layers.
Implementation Method 1
bonding the copper boards on the aluminum circuit layers by solid phase diffusion
Implementation Method 2
pressing the laminate in a lamination direction by moving the support boards to a facing direction
Implementation Method 3
heating in this pressing state, so as to bond the copper boards on the aluminum circuit layers by solid phase diffusion
Data Source
AI summary
Forming aluminum circuit layers forming an aluminum circuit layers on one surface of a ceramic substrate and forming copper circuit layers are included. The copper circuit layers are formed by laminating copper boards for the circuit layers on the respective aluminum circuit layers, arranging the laminate between a pair of support boards having a convex curved surface at least on one surface so as to face to each other, moving the support boards in a facing direction to press the laminate in a lamination direction, and heating in this pressing state so that the copper boards for the circuit layers are bonded on the aluminum circuit layers respectively by solid phase diffusion. In the step of forming the copper circuit layers, the support boards are arranged so that either one of the convex curved surface is in contact with the adjacent copper boards for the circuit layers in the laminate.