Metal-Ceramic Substrate Bonding Layer Surface Resistance
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Solution Overview
Problem
Existing metal-ceramic substrates face challenges in achieving strong and reliable bonding between metal and ceramic layers, often resulting in brittle intermetallic phases that reduce peel strength and service life.
Innovation Solution
A carrier substrate with a bonding layer having a surface resistance greater than 5 ohm/sq, achieved by optimizing the proportion and distribution of active metal in the bonding layer, which reduces the formation of brittle intermetallic phases and enhances the bond strength between the metal and ceramic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bonding layer with low surface resistance is used to ensure good electrical conductivity, then electrical conductivity is improved, but the formation of brittle intermetallic phases increases and peel strength decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the surface resistance of the bonding layer to a specific range (>5 ohm/sq) and controlling the thickness of the adhesive layer (<10 micrometers). These parameter adjustments resolve the contradiction by finding the optimal balance between electrical conductivity and mechanical strength, preventing excessive intermetallic phase formation while ensuring adequate bond strength.
Solution Approach 2:
The bonding layer is designed as a composite structure combining metallic phases for conductivity with controlled intermetallic phases for bonding strength. This composite approach allows the layer to simultaneously achieve electrical conductivity and mechanical strength by distributing different phases strategically within the bonding interface.
2Strength
If the adhesive layer is made thin to improve bonding strength, then peel strength is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent replaces mechanical thickness control methods with a chemistry-based approach by formulating the solder material with specific active metal content and composition. This chemical formulation self-regulates the adhesive layer thickness during bonding, reducing the need for precise mechanical control while ensuring consistent thin layer formation.
Solution Approach 2:
The bonding process is designed to be self-regulating, where the solder material composition and bonding conditions automatically control the adhesive layer thickness. The system self-adjusts to form layers within the target thickness range without requiring external intervention or complex control mechanisms, thereby reducing manufacturing precision requirements.
3Strength
If active metal content in the bonding layer is increased to improve bonding to ceramic, then bond strength is improved, but brittle intermetallic phases increase and reduce service life
Solution Approach 1:
The patent applies parameter changes by optimizing the active metal content within a specific range and controlling the surface resistance to >5 ohm/sq. These parameter adjustments ensure sufficient chemical reactivity for strong ceramic bonding while limiting excessive intermetallic phase formation, thereby maintaining service life.
Solution Approach 2:
The bonding layer exhibits local quality variations with different phases distributed strategically: active metal-rich regions provide chemical bonding to ceramic, while metallic phase regions provide ductility and conductivity. This local differentiation allows simultaneous achievement of strong bonding and long service life by placing the right material properties at the right locations.
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 results in a stronger and more reliable bond between the metal and ceramic layers, improving the service life of the carrier substrate by minimizing the formation of brittle intermetallic phases and ensuring a thin, homogeneous adhesive layer.
Implementation Method 1
The active metal, which is for example at least one element selected from the group consisting of Hf, Ti, Zr, Nb, Ce, creates a bond between the solder and the ceramic material by chemical reaction
Data Source
AI summary
A support substrate (1), in particular a metal-ceramic substrate, as a support for electric components, comprising: —at least one metal layer (10) and—an insulating element (30), in particular a ceramic element, a glass element, a glass ceramic element, and/or a high temperature-resistant plastic element. The at least one metal layer (10) and the insulating element (30) extend along a main extension plane (HSE) and are arranged one over the other in a stacking direction (S) running perpendicularly to the main extension plane (HSE), wherein in a completed support substrate (1), a binding layer (12) is formed between the at least one metal layer (10) and the insulating element (30), and an adhesive layer (13) of the binding layer (12) has a surface resistance which is greater than 5 Ohm/sq.