Laser Sealing of Ceramic Base and Glass Substrate
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Solution Overview
Problem
Laser sealing methods face challenges in increasing bonding strength between the element base and the sealing material layer in hermetic packages, particularly when the element base is made of ceramic, leading to thermal degradation and reduced long-term reliability.
Innovation Solution
A method involving the formation of a sealing material layer on a ceramic base through firing, followed by laser sealing with a glass substrate to enhance bonding strength, using a bismuth-based glass with refractory fillers to ensure a sufficient reaction layer and improved thermal stability, while maintaining the hermetic integrity of the package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser sealing is used to seal the element base and glass substrate, then thermal degradation of the element is prevented, but bonding strength between the element base and sealing material layer is insufficient
Solution Approach 1:
The sealing material layer is formed on the element base before the laser sealing process. This preliminary formation allows the sealing material to be in close contact with the element base surface, ensuring strong bonding while maintaining the advantages of laser sealing. The sealing material layer is applied, dried, and fired before the actual sealing operation, creating a prepared interface for strong bonding.
Solution Approach 2:
The patent controls the thickness of the sealing material layer within a specific range (1-10 μm) to optimize both bonding strength and laser sealing effectiveness. By adjusting this parameter, the patent achieves sufficient bonding strength while maintaining the rapid heating characteristics of laser sealing that prevent thermal degradation of the element.
2Strength
If traditional firing sealing is used to increase bonding strength, then bonding strength between element base and sealing material layer is improved, but thermal degradation of the element occurs
Solution Approach 1:
The patent replaces traditional thermal firing sealing with laser sealing. Instead of using conventional heating methods that cause thermal degradation, the patent employs laser energy to rapidly heat and melt the sealing material layer, achieving strong bonding without subjecting the temperature-sensitive element to prolonged high-temperature exposure.
Solution Approach 2:
The patent utilizes the phase transition of the sealing material from solid to liquid state through rapid laser heating. The sealing material is heated above its melting point, flows to fill gaps and create strong bonds, then rapidly cools and solidifies, forming a strong bond between the element base and glass substrate without prolonged thermal exposure to the element.
3Productivity
If the sealing material layer is formed thinly for laser sealing, then the sealing process is rapid, but the reaction layer is insufficient and bonding strength decreases
Solution Approach 1:
The patent optimizes the thickness of the sealing material layer to a specific range (1-10 μm) that balances sealing speed and bonding strength. This parameter control ensures the layer is thin enough for rapid laser heating and sealing while being sufficiently thick to generate an adequate reaction layer and achieve strong bonding.
Solution Approach 2:
The patent uses a sealing material comprising glass powder and refractory filler in specific proportions. This composite composition enables the material to form a strong reaction layer rapidly under laser heating, achieving both high bonding strength and fast sealing speed by combining the reactivity of glass with the thermal stability of refractory materials.
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 approach significantly increases the bonding strength between the ceramic base and the sealing material layer, preventing thermal degradation and enhancing the long-term reliability of the hermetic package by ensuring a strong and stable seal.
Implementation Method 1
irradiating the sealing material layer with laser light from a glass substrate side to seal the ceramic base and the glass substrate with each other through intermediation of the sealing material layer
Implementation Method 2
the laser sealing is a method involving locally heating the sealing material layer to cause the sealing material layer to soften and flow
Implementation Method 3
locally heating the sealing material layer to cause the sealing material layer to soften and flow
Implementation Method 4
reaction time between the element base and the sealing material layer is also shortened. As a result, a reaction layer is not sufficiently generated at an interface between the element base and the sealing material layer
Data Source
AI summary
A technical object of the present invention is to devise a method by which bonding strength between an element base and a sealing material layer can be increased without thermal degradation of a member to be housed inside, to thereby improve long-term reliability of a hermetic package. A method of producing a hermetic package of the present invention includes the steps of: preparing a ceramic base and forming a sealing material layer on the ceramic base; preparing a glass substrate and arranging the ceramic base and the glass substrate so that the glass substrate is brought into contact with the sealing material layer on the ceramic base; and irradiating the sealing material layer with laser light from a glass substrate side to seal the ceramic base and the glass substrate with each other through intermediation of the sealing material layer, to thereby provide a hermetic packages.