Silver-Anchored Bonded Substrate for Strong Ceramic-Copper Adhesion
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Solution Overview
Problem
Conventional bonded substrates with silicon nitride ceramic substrates and copper plates often suffer from poor adhesion strength of the bonding layer, leading to inadequate cold durability and insulation resistance.
Innovation Solution
The bonded substrate includes a silicon nitride ceramic substrate, a copper plate, a bonding layer, and penetrating regions. The copper plate and bonding layer are patterned and disposed over the substrate, with penetrating regions containing silver that penetrate into the substrate, enhancing adhesion strength and reducing insulation resistance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal plate is bonded to a ceramic substrate with few white spots on the surface, then the bonding structure is simpler, but the anchoring effect is poor and bonding strength is insufficient
Solution Approach 1:
The patent creates penetrating regions (anchoring holes) in advance on the ceramic substrate surface before bonding the metal plate. These pre-formed structures provide anchoring points that enhance bonding strength without requiring complex surface treatments during the bonding process itself.
Solution Approach 2:
The patent utilizes a porous structure by creating penetrating regions that extend into the ceramic substrate. This porous configuration increases the surface area and provides mechanical interlocking, thereby improving bonding strength while maintaining a relatively simple overall structure.
2Reliability
If the number of white spots on the ceramic substrate surface is increased to 50-200 per square millimeter, then bonding strength and dielectric strength are improved, but ion migration occurs when voltage is applied to patterned portions
Solution Approach 1:
The patent creates penetrating regions at specific localized positions rather than uniformly distributing white spots across the entire surface. This local quality approach provides anchoring effects where needed while avoiding the widespread ion migration issues associated with high densities of surface defects.
Solution Approach 2:
The penetrating regions are formed in advance through controlled processes (such as laser drilling or etching) before bonding. This preliminary action creates well-defined anchoring structures that prevent ion migration pathways, unlike the uncontrolled white spots that form during ceramic manufacturing.
3Strength
If conventional brazing materials containing titanium hydride and silver-copper powder are used, then bonding layer formation is achieved, but adhesion strength to the silicon nitride ceramic substrate is insufficient
Solution Approach 1:
The patent forms penetrating regions in advance before applying the brazing material layer. This preliminary structural preparation provides mechanical anchoring that works in conjunction with the chemical bonding from conventional brazing materials, thereby enhancing adhesion strength without requiring complex modifications to the brazing process itself.
Solution Approach 2:
The patent creates a composite bonding structure that combines the mechanical anchoring effect of penetrating regions with the chemical bonding properties of conventional brazing materials (titanium hydride and silver-copper powder). This composite approach achieves superior adhesion strength while maintaining ease of manufacture by using established materials and processes.
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 solution improves the adhesion strength of the bonding layer to the silicon nitride ceramic substrate, achieving high cold durability and maintaining insulation resistance between patterns, thereby enhancing the overall performance of the bonded substrate.
Implementation Method 1
The penetrating regions contain silver, and are formed so that the number of penetrating regions present per square millimeter of the main surface of the silicon nitride ceramic substrate is one or more and 30 or less. The penetrating regions containing silver interfere with separation of the bonding layer from the silicon nitride ceramic substrate.
Implementation Method 2
The bonded substrate is manufactured by manufacturing an intermediate product including a brazing material layer between the copper plate and the silicon nitride ceramic substrate, and heat treating the manufactured intermediate product to generate the bonding layer between the copper plate and the silicon nitride ceramic substrate
Implementation Method 3
The intermediate product is heat treated to generate a bonding layer bonding the copper plate to the main surface of the silicon nitride ceramic substrate, and a plurality of penetrating regions each including one or more penetrating portions penetrating continuously from the bonding layer into the silicon nitride substrate
Data Source
AI summary
The bonded substrate includes the silicon nitride ceramic substrate, a copper plate, the bonding layer, and penetrating regions. The copper plate and the bonding layer are patterned into a predetermined shape, and are disposed over a main surface of the silicon nitride ceramic substrate. The bonding layer bonds the copper plate to the main surface of the silicon nitride ceramic substrate. The penetrating regions each include one or more penetrating portions penetrating continuously from the main surface of the substrate into the silicon nitride ceramic substrate to a depth of 3 μm or more and 20 μm or less, and contain silver, and the number of penetrating regions present per square millimeter of the main surface of the substrate is one or more and 30 or less.