Composite Ceramic Substrate Bonding With Low-Silver Active Metal Layers
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Solution Overview
Problem
Conventional ceramic substrate production methods using high silver content face issues of electromigration and high cost due to the high silver content.
Innovation Solution
A composite ceramic substrate is developed with a ceramic board, circuit board, and a composite adhering structure comprising first and second active metal layers made of group IV or V metals or titanium hydride, and a solder layer of tin and copper, produced through printing and sintering processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high content of silver is used in active metal brazing process, then the brazing strength is improved, but the probability of electromigration increases and the production cost increases
Solution Approach 1:
The patent changes the material composition parameters by replacing silver with group IV metals (Ti, Zr, Hf) and group V metals (V, Nb, Ta). This substitution maintains brazing strength while eliminating the electromigration issues associated with high silver content, directly resolving the technical contradiction between strength and reliability
Solution Approach 2:
The patent employs composite material structures with multiple layers including active metal layers (group IV/V metals), solder layers (Sn-Cu), and ceramic substrates. This composite approach achieves both strong brazing joints and improved reliability by distributing functions across different material layers, avoiding the electromigration problems of pure silver-based systems
2Strength
If high content of silver is used in active metal brazing process, then the brazing strength is improved, but the production cost increases
Solution Approach 1:
The patent substitutes expensive silver with more economical group IV and group V metals. These alternative materials provide comparable brazing strength at lower cost, directly addressing the contradiction between maintaining strength and reducing production cost associated with high silver content
Solution Approach 2:
The patent modifies the compositional parameters by reducing silver content and introducing cost-effective alternative metals. This parameter change achieves the dual goal of maintaining adequate brazing strength while significantly reducing material costs
3Ease of manufacture
If conventional active metal brazing process is used, then the manufacturing process is simple, but the electromigration probability increases
Solution Approach 1:
The patent changes the material parameters from silver-based to group IV/V metal-based active metal layers. This substitution maintains the simplicity of the brazing process while eliminating electromigration risks, resolving the contradiction between ease of manufacture and reliability
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 composite ceramic substrate achieves improved tensile strength and reduces the probability of electromigration and production costs by minimizing silver content.
Implementation Method 1
The sintering process is implemented by sintering the circuit board, the first active metal layer, the second active metal layer, the solder layer, and the ceramic board that are assembled at a temperature of between 800° C. and 1,000° C. and under a pressure of between 5×10−6 torr and 5×10−4 torr for 20 minutes to 50 minutes
Data Source
AI summary
A composite ceramic substrate and method for producing the composite ceramic substrate are provided. The composite ceramic substrate includes a ceramic board, a circuit board, and a composite adhering structure adhered to the ceramic board and the circuit board. The composite adhering structure includes a first active metal layer, a second active metal layer, and a solder layer. The first active metal layer includes an active metal material, the active metal material is selected from the group consisting of a group IV metal, a group V metal, and titanium hydride. The group IV metal is titanium, zirconium, or hafnium, and the group V metal is vanadium, niobium, or tantalum. The second active metal layer is made of titanium or titanium hydride. The solder layer includes tin and copper. The composite ceramic substrate has a tensile strength between 100 N/cm and 340 N/cm.