Hermetic Ferrule Assembly With Laser-Bonded Dielectric Substrate
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Solution Overview
Problem
Existing techniques for bonding dielectric materials to metal materials in hermetic assemblies require high temperatures and surface polishing, which can lead to thermal stresses and increased complexity.
Innovation Solution
A hermetic assembly is developed that includes a ferrule with a flange welded to a patterned layer on a dielectric substrate, eliminating the need for surface polishing and high-temperature processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature bonding processes are used to join dielectric materials to metal materials, then hermetic sealing is achieved, but thermal stresses increase and manufacturing complexity increases
Solution Approach 1:
The bonding process is divided into two distinct stages: first, a low-temperature eutectic bond is formed between the metal flange and dielectric substrate; second, a high-temperature hermetic seal is created only where needed through glass frit bonding. This segmentation allows the system to achieve hermetic sealing without subjecting the entire assembly to high temperatures, thereby reducing thermal stresses.
Solution Approach 2:
The invention utilizes eutectic bonding at a specific temperature parameter (below the softening point of the dielectric) to create an initial bond, then applies glass frit material that undergoes phase change at a higher temperature to create the hermetic seal. This parameter-based approach allows selective application of heat to achieve sealing without globally high-temperature exposure.
2Manufacturing precision
If surface polishing is performed on metal and dielectric surfaces before bonding, then bonding quality improves, but manufacturing complexity and time increase
Solution Approach 1:
The eutectic bonding mechanism itself provides the surface preparation function. The low-temperature bonding process naturally creates a clean, bonded interface without requiring separate polishing or surface treatment steps. The metallization layer and dielectric surface bond directly through the eutectic reaction, making the bonding process self-preparatory.
3Strength
If thick housing sidewalls are used to accommodate high-temperature bonding processes, then structural integrity is maintained, but space for electronic components is reduced
Solution Approach 1:
By changing the bonding temperature parameter to a lower eutectic bonding temperature, the housing sidewalls can be made thinner because the lower temperature process generates less thermal stress and requires less structural mass to withstand thermal loads. This parameter change enables both reduced housing thickness and increased internal volume for electronics.
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
This solution simplifies the attachment of a housing to the dielectric substrate, reduces thermal stresses, and allows for thinner housing sidewalls and more space for electronic components, while maintaining a hermetic seal.
Implementation Method 1
The flange is welded to a welding portion of the patterned layer
Implementation Method 2
a patterned layer connected to the first major surface of the dielectric substrate by a laser bond
Data Source
AI summary
Various embodiments of a hermetic assembly and a method of forming such assembly are disclosed. The hermetic assembly includes a dielectric substrate having a first major surface and a second major surface, a patterned layer connected to the first major surface of the dielectric substrate by a laser bond, and a ferrule having a body and a flange extending from the body. The flange is welded to a welding portion of the patterned layer that is disposed between the flange and the first major surface of the dielectric substrate such that the ferrule is hermetically sealed to the dielectric substrate.