Buffer Gas Dynamic Sealing Between Ultra-Clean Vacuum Zones
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Solution Overview
Problem
Existing sealing techniques in vacuum chambers for semiconductor inspection systems fail to provide a dynamic seal between movable components, leading to contamination and performance degradation, especially as semiconductor dimensions shrink and require precise movement.
Innovation Solution
A dynamic seal is achieved by injecting a buffer gas into the gap between movable components using a gas injector, creating a gas curtain that prevents contaminants from transferring between vacuum zones, even during movement, while maintaining ultra-high vacuum pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If narrow gaps or labyrinth type seals are used between movable components, then the amount of material transfer between zones is reduced, but a complete dynamic seal is not achieved
Solution Approach 1:
A buffer gas (such as nitrogen or helium) is introduced as an intermediary substance into the gap between movable components. The buffer gas creates a pressure differential that prevents vacuum contaminants from crossing the interface between vacuum zones, while allowing the components to move relative to each other. This mediator approach achieves complete dynamic sealing without restricting component motion.
Solution Approach 2:
The invention uses pneumatic principles by introducing a buffer gas at controlled pressure into the gap between movable components. The gas flow is regulated to maintain a pressure barrier that blocks contaminant transfer while accommodating the relative motion of components. This pneumatic sealing mechanism provides reliable dynamic sealing where mechanical seals would fail.
2Ease of operation
If actuators are used to move components for alignment, then precise movement is achieved, but contaminants are generated that can land on critical surfaces
Solution Approach 1:
The vacuum chamber is divided into separate vacuum zones with distinct pressure levels. Actuators generating contaminants are placed in a less stringent vacuum zone, while critical surfaces are located in a higher vacuum zone. The buffer gas seal at the interface between zones prevents contaminant migration, allowing actuators to function without compromising the cleanliness of critical areas.
Solution Approach 2:
The buffer gas acts as a protective intermediary layer between the actuator zone and the critical surface zone. It prevents actuator-generated contaminants from reaching critical surfaces while allowing the actuators to perform their alignment functions. This mediator approach enables precise component movement without the harmful side effect of contaminating critical areas.
3Reliability
If typical elastomeric or metal knife-edge seals are used between vacuum zones, then sealing between static components is achieved, but dynamic sealing during movement is not effective
Solution Approach 1:
The invention replaces mechanical contact seals (elastomeric or metal knife-edge) with a pneumatic buffer gas seal. This substitution eliminates the need for physical contact between sealing surfaces, allowing unlimited relative motion between components while maintaining sealing effectiveness. The buffer gas pressure barrier provides sealing without the mechanical constraints that limit dynamic seal performance.
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 effectively prevents cross-contamination and maintains an ultra-clean vacuum environment, reducing the need for invasive maintenance and ensuring high-yield semiconductor production by providing a reliable dynamic seal between movable components in vacuum chambers.
Implementation Method 1
injecting a buffer gas into the gap between movable components using a gas injector, creating a gas curtain that prevents contaminants from transferring between vacuum zones
Implementation Method 2
The vacuum chamber may comprise a first vacuum zone and a second vacuum zone... At least one of the first vacuum zone and the second vacuum zone may be at an ultra-high vacuum pressure
Data Source
AI summary
An apparatus includes a vacuum chamber, a first component, a second component that is movable relative to the first component, and a gas injector. The vacuum chamber includes a first vacuum zone and a second vacuum zone. The first component is disposed in the first vacuum zone at an interface with the second vacuum zone. The second component is disposed in the second vacuum zone at the interface and separated from the first component by a gap. The gas injector is configured to inject a buffer gas in the gap between the first component and the second component from at least one hole in at least one of the first component and the second component. The buffer gas provides a dynamic seal between the first vacuum zone and the second vacuum zone during movement of the second component relative to the first component.