Ceramic Circuit Substrate Silver Plating Migration Resistance
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Solution Overview
Problem
Ceramic circuit substrates face issues with silver plating causing migration and poor adhesiveness with module sealing resins, leading to reliability concerns and reduced performance due to silver's reactivity and lack of close adhesiveness with power module sealing materials.
Innovation Solution
A ceramic circuit substrate design where only the main surfaces of a copper plate bonded to a ceramic substrate are silver plated, with the silver plating thickness between 0.1 μm to 1.5 μm and surface roughness of 0.1 μm to 1.5 μm, while the side surfaces remain un plated, enhancing anti-migration properties and adhesiveness with module sealing resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entire copper plate surface is silver plated, then bonding strength with semiconductor elements is improved, but silver migration causes short circuits between conductors
Solution Approach 1:
The patent applies silver plating selectively only to the main surfaces of the copper plate where semiconductor elements are mounted, while deliberately leaving the side surfaces unplated. This local differentiation ensures high bonding strength at the component mounting locations while preventing silver migration pathways that would occur along the side surfaces, thereby resolving the contradiction between bonding strength and short circuit resistance.
2Strength
If silver plating is applied to improve bonding, then bonding strength increases, but close adhesiveness with module sealing resin deteriorates
Solution Approach 1:
The patent creates a local quality distinction by plating only the main surfaces and leaving side surfaces unplated. The unplated side surfaces provide excellent close adhesiveness with the module sealing resin, while the plated main surfaces ensure strong bonding with semiconductor elements. This spatial differentiation resolves the contradiction between bonding strength and sealing resin adhesion.
3Strength
If silver plating thickness is increased to improve bonding, then bonding strength increases, but silver migration resistance decreases
Solution Approach 1:
The patent extracts the silver plating from the side surfaces while maintaining it on the main surfaces. By removing the plating from areas where migration occurs (side surfaces) while preserving it where bonding is needed (main surfaces), the patent achieves both strong bonding and migration resistance simultaneously.
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 approach results in improved migration resistance and high close adhesiveness with module sealing resins, ensuring reliable bonding and performance of semiconductor elements on ceramic circuit substrates.
Implementation Method 1
the copper plate of at least one of the main surfaces being subjected to silver plating
Data Source
AI summary
A ceramic circuit substrate is suitable for silver nanoparticle bonding of semiconductor elements and has excellent close adhesiveness with a power module sealing resin. A ceramic circuit substrate has a copper plate bonded, by a braze material, to both main surfaces of a ceramic substrate including aluminum nitride or silicon nitride, the copper plate of at least one of the main surfaces being subjected to silver plating, wherein: the copper plate side surfaces are not subjected to silver plating; the thickness of the silver plating is 0.1 μm to 1.5 μm; and the arithmetic mean roughness Ra of the surface roughness of the circuit substrate after silver plating is 0.1 μm to 1.5 μm.