Sacrificial Intermediate Layer for Low-Stress Mechanical Interfaces
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Solution Overview
Problem
Current methods for bonding or fastening components in lithographic and semiconductor manufacturing processes, such as using epoxies or fasteners, often introduce thermal stress and risk breakage due to differences in coefficient of thermal expansion (CTE) and imperfections between surfaces.
Innovation Solution
Incorporating an intermediate layer with a low coefficient of thermal expansion material, such as ZERODUR®, between substrates to act as a sacrificial point of failure, reducing damage to the reticle stage and substrates by absorbing applied forces and stresses, and using a bonding or fastening system that includes a clamp or fastener to secure the intermediate layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxies or adhesive materials are used to attach components, then bonding strength is improved, but thermal stress is introduced due to difference in coefficient of thermal expansion
Solution Approach 1:
The patent introduces an intermediate layer between the first substrate and second substrate that acts as a mediator. This intermediate layer has a coefficient of thermal expansion matched to one of the substrates, thereby reducing thermal stress while maintaining bonding strength through the sacrificial failure mechanism.
Solution Approach 2:
The patent changes the material parameters of the intermediate layer, specifically selecting materials with low coefficient of thermal expansion (such as ZERODUR®, tempered ceramic, or plastic) to match the substrates, thereby minimizing thermal stress during temperature variations.
2Strength
If fasteners are used to join pieces of material, then mechanical strength is improved, but breakage or cracks occur in the layers joined
Solution Approach 1:
The intermediate layer serves as a protective intermediary between the fasteners and the substrates. When fasteners are used, the intermediate layer absorbs the mechanical stress and fails first, preventing direct damage to the valuable substrates.
Solution Approach 2:
The intermediate layer provides beforehand cushioning by being positioned between the fasteners and substrates. It is designed to fail first under excessive force, thereby cushioning and protecting the substrates from breakage or cracks before stress is applied.
3Ease of manufacture
If fasteners are used to join pieces of material, then assembly simplicity is improved, but stress concentrations occur due to imperfections between surfaces
Solution Approach 1:
The intermediate layer acts as a stress-distributing intermediary between fasteners and substrates. It compensates for surface imperfections and distributes stress more evenly, preventing stress concentrations that would otherwise occur at imperfection sites.
4Stress or pressure
If an intermediate layer is added to reduce thermal stress, then thermal stress is reduced, but device complexity increases
Solution Approach 1:
The intermediate layer is designed as a sacrificial, disposable component that is cheaper and simpler to replace than the substrates. This allows the system to maintain simplicity in terms of replaceability, where the intermediate layer absorbs complexity through its sacrificial failure mechanism.
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 effectively reduces thermal stress and breakage risk by allowing the intermediate layer to fail before the substrates, thereby protecting them and improving the reliability and efficiency of the bonding or fastening process.
Implementation Method 1
the intermediate layer is configured to be a first point of failure or breakage of the intermediate apparatus under an applied force
Implementation Method 2
the intermediate layer comprises a low coefficient of thermal expansion or ultra-low expansion material
Data Source
AI summary
An apparatus includes a first substrate, a second substrate, and an intermediate layer disposed between the first and second substrates. The intermediate layer is configured to be a first point of failure or breakage of the apparatus under an applied force. The apparatus can further include a bonding layer disposed between the first and second substrates. The bonding layer is configured to bond the intermediate layer to the first and second substrates. The apparatus can further include a fastener coupled to the first and second substrates. The fastener is configured to secure the intermediate layer to the first and second substrates. The intermediate layer can include a coating applied to the first substrate or the second substrate. The apparatus can further include a second intermediate layer disposed between the first substrate and the fastener or the second substrate and the fastener.