Glass-to-Ceramic Joining with Intermediate Glass for Thermal Stability
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Solution Overview
Problem
Existing methods for joining glass elements to support elements, such as in semiconductor exposure machines, face challenges with thermal expansion mismatches leading to surface unevenness and graphite formation issues, particularly with ULE glass and SiSiC ceramic, which cannot be directly welded.
Innovation Solution
A method involving an intermediate glass material with a matching coefficient of expansion to the support element, which is first welded or soldered to the support, and then the glass element is joined to the intermediate material using selective thermal methods like laser welding, avoiding direct adhesive use and minimizing thermal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If direct joining of glass element to support element is performed by adhesion or soldering, then joining is achieved, but surface unevenness occurs due to thermal expansion mismatch
Solution Approach 1:
An intermediate glass material layer is introduced between the glass element and support element. This intermediate layer has a coefficient of thermal expansion that matches the support element, serving as a mediator that accommodates thermal expansion differences and prevents surface unevenness while maintaining strong joining through controlled local heating.
Solution Approach 2:
The coefficient of thermal expansion is used as a key parameter to select the appropriate intermediate glass material. By matching the thermal expansion parameters between the intermediate layer and support element, the system achieves thermal compatibility that eliminates surface distortion during temperature variations.
2Strength
If ULE glass is directly welded to SiSiC ceramic, then joining is achieved, but graphite formation occurs
Solution Approach 1:
The intermediate glass material acts as a barrier between ULE glass and SiSiC ceramic, preventing direct contact that would cause graphite formation. This intermediary layer enables successful joining while eliminating the harmful graphite formation issue that occurs with direct welding of these materials.
3Strength
If adhesive is used to join glass element to support element, then joining is achieved, but adhesive softening occurs during heating
Solution Approach 1:
The invention replaces the adhesive (which has limited thermal stability) with a glass-based joining system. The intermediate glass material and glass element are joined through localized melting and bonding, creating a permanent, thermally stable connection that does not soften during heating, effectively substituting a thermally unstable component with a thermally stable one.
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 enables a thermally stable, adhesive-free joining of glass and ceramic components with minimal surface distortion, even under temperature variations, ensuring a smooth surface at room temperature and reducing the risk of graphite formation.
Implementation Method 1
the intermediate glass material has a third coefficient of expansion which substantially corresponds to the second coefficient of expansion... for temperature changes, for example during welding, it may experience similar stress changes as the support element
Implementation Method 2
local heating of the intermediate glass material in order to join the glass element to the support element via the intermediate glass material
Implementation Method 3
the glass element and the intermediate glass material are heated simultaneously by means of laser
Data Source
AI summary
The invention relates to a method for thermally stable joining of a glass element to a support element, wherein the glass element has a first coefficient of expansion and the support element has a second coefficient of expansion differing from the first coefficient of expansion. The method thus comprises a step of attaching an intermediate glass material to the support element, wherein the intermediate glass material has a third coefficient of expansion which substantially corresponds to the second coefficient of expansion. In addition, the method comprises a step of local heating of the intermediate glass material in order to join the glass element to the support element via the intermediate glass material.