PCB Ceramic-Metal Bonding via Ti-Ag Deposition Layers
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Solution Overview
Problem
Existing methods for manufacturing printed circuit boards face challenges in achieving strong interlayer bonding strength while minimizing production costs, particularly due to thermal stress and differential thermal expansion coefficients between ceramic substrates and metal sheets, leading to potential peeling.
Innovation Solution
A method involving the use of ceramic substrates with deposition layers on opposing surfaces, paired with metal sheets having larger surface areas, followed by hot-pressing to bond the metal sheets and ceramic substrates via deposition layers, optimizing the deposition amounts of Ti and Ag to enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diffusion bonding method is used to form thin deposition layer, then bonding strength and thermal shock characteristics are improved, but production cost increases
Solution Approach 1:
The patent segments the bonding process into two distinct stages: first forming a thin deposition layer (several hundred nanometers) through diffusion bonding to ensure strong adhesion, then adding a thicker metal layer through screen printing or similar low-cost methods. This segmentation allows each layer to serve its specific function while optimizing the overall cost structure.
Solution Approach 2:
The patent changes the deposition amount parameter by differentiating between the deposition layer (several hundred nanometers) and the metal layer (thicker layer). This parameter differentiation enables the deposition layer to provide strong bonding while the metal layer provides cost-effective material properties, resolving the contradiction between bonding strength and production cost.
2Strength
If active metal brazing is used with Ag paste, then bonding strength is improved, but Ag diffusion to edge portion occurs during operation
Solution Approach 1:
The patent introduces a deposition layer as an intermediary between the substrate and the metal layer. This deposition layer acts as a barrier that prevents Ag diffusion to the edge portion while maintaining strong bonding strength, thus resolving the contradiction between bonding strength and Ag diffusion prevention.
3Ease of manufacture
If direct bonding using oxide layer is used, then production cost is reduced, but thermal conductivity is lowered
Solution Approach 1:
The patent applies local quality by creating a deposition layer with specific material properties (high thermal conductivity) at the critical bonding interface, while using different materials (oxide layer) in other regions where thermal conductivity is less critical. This localized optimization maintains high thermal conductivity where needed while keeping production costs low.
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 results in a printed circuit board with enhanced bonding strength and reduced production costs, effectively preventing peeling even under thermal shock conditions.
Implementation Method 1
a deposition layers are formed on the upper and lower surfaces of the ceramic substrate having the area SA
Implementation Method 2
the diffusion bonding method can form a thin deposition layer with a thickness of several hundred nanometers by solid phase reaction
Data Source
AI summary
This application relates to a method for manufacturing a printed circuit board. According to the present application, it is possible to manufacture a printed circuit board having excellent bonding strength between a ceramic substrate and a metal sheet, and the manufacturing cost thereof can be reduced.