Sintered Joint Between Ceramic Substrate and Carrier
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Solution Overview
Problem
Ceramic substrates joined with a carrier often experience cracks during the production of composite materials due to thermal expansion mismatches and mechanical stresses, which compromises the integrity of the sintered joint.
Innovation Solution
A method involving pre-heating the carrier to a threshold temperature and applying pressure to a powder-including layer between the carrier and ceramic substrate, ensuring the powder is sintered at elevated temperatures and pressures to form a stable joining layer, thereby reducing the risk of cracks by managing thermal expansion and mechanical loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a ceramic substrate is joined with a carrier using conventional bonding methods, then mechanical stabilization and heat dissipation are improved, but cracks occur in the ceramic layer due to thermal expansion mismatches and mechanical stresses
Solution Approach 1:
The carrier is pre-heated to a threshold temperature before the sintering process begins. This preliminary heating action allows the ceramic substrate to be gradually acclimated to the thermal environment, reducing thermal shock and preventing cracks during subsequent heating and cooling cycles
Solution Approach 2:
The sintering process utilizes controlled changes in temperature and pressure parameters. By gradually increasing temperature to a threshold level and applying controlled pressure, the powder-including layer transforms into a joining layer that accommodates thermal expansion differences, preventing ceramic layer cracking
2Strength
If high pressure is applied during sintering to ensure strong bonding, then joint strength is improved, but mechanical stresses increase causing cracks in the ceramic layer
Solution Approach 1:
The sintering process employs controlled pressure parameters applied at elevated temperatures. The pressure is increased from an initial value to a threshold pressure, but the combination of temperature and pressure creates a joining layer that reduces stress concentration, preventing ceramic layer failure
Solution Approach 2:
The powder-including layer acts as an intermediary substance between the ceramic substrate and carrier. During sintering, this layer transforms into a joining layer that absorbs and distributes mechanical stresses, preventing direct stress transmission to the ceramic layer that would cause cracking
3Productivity
If rapid heating is used to reduce production time, then productivity is improved, but thermal expansion mismatches cause cracks in the ceramic layer
Solution Approach 1:
The carrier is pre-heated to a threshold temperature before full sintering begins. This preliminary action allows gradual thermal acclimation of the ceramic substrate, preventing thermal shock cracks while maintaining overall process efficiency
Solution Approach 2:
The sintering process uses periodic or staged heating and pressing cycles. Temperature and pressure are increased in controlled stages rather than instantly, allowing the ceramic substrate to adapt progressively and preventing cracks while maintaining reasonable production time
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 method effectively prevents or reduces the occurrence of cracks in the ceramic layer by creating a strong, stable sintered joint that withstands thermal expansion differences and mechanical stresses, enhancing the reliability of ceramic substrate-carrier assemblies.
Implementation Method 1
cracks in the ceramic layer of a ceramic substrate joined with a carrier can occur during the production of a composite that includes a ceramic substrate joined with a carrier
Implementation Method 2
the powder-including layer is sintered by simultaneously keeping the pressure for at least a minimum sintering time at at least the first pressure threshold and the temperature of the carrier at at least the first temperature threshold so that the powder-including layer is converted into a joining layer joining the carrier and the ceramic substrate
Data Source
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AI summary
A method for producing a sintered joint between a ceramic substrate and a carrier is disclosed. The method includes pre-heating the carrier by increasing a temperature of the carrier from an initial temperature to at least a first threshold temperature. A pressure, with which the pre-heated carrier, the ceramic substrate and a powder-including layer disposed between the pre-heated carrier and the ceramic substrate are pressed against one another, is increased from an initial pressure of less than or equal to an initial pressure threshold to at least a first pressure threshold, and the powder-including layer is sintered by simultaneously keeping the pressure for at least a minimum sintering time at at least the first pressure threshold and the temperature of the carrier at at least the first temperature threshold so that the powder-including layer is converted into a joining layer joining the carrier and the ceramic substrate. Thereby, the first temperature threshold is a temperature which allows for sintering the powder-including layer when it is heated to that temperature.