Slit Valve Doors for Load Lock Vacuum Integrity
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Solution Overview
Problem
In semiconductor processing, load lock chambers face challenges in maintaining vacuum integrity when interfacing with atmospheric pressure environments, leading to inefficiencies in substrate throughput and potential leaks due to inadequate sealing mechanisms.
Innovation Solution
The implementation of slit valve doors within load lock chambers that seal against internal surfaces when between transfer chambers, and external surfaces when interfacing with a factory interface, utilizing atmospheric pressure to maintain vacuum seal integrity, with actuators controlling the doors' operation to ensure effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing mechanisms are used in load lock chambers, then the structure is simple, but vacuum integrity cannot be maintained when interfacing with atmospheric pressure environments
Solution Approach 1:
The patent employs flexible slit valve doors that can deform under pressure differential to maintain sealing. The doors are designed to flex against the chamber wall, using the pressure difference between atmospheric and vacuum sides to enhance the seal rather than overcome it, thereby maintaining vacuum integrity without complex mechanical sealing systems
Solution Approach 2:
The patent converts the harmful atmospheric pressure that tends to push doors open into a beneficial force that presses the flexible doors against the chamber wall, enhancing the vacuum seal. By orienting the seal surface perpendicular to the pressure differential, the atmospheric pressure becomes a sealing force rather than a leakage source
2Reliability
If load lock chambers are designed with adequate sealing mechanisms, then vacuum integrity is maintained, but substrate throughput efficiency decreases due to additional sealing steps
Solution Approach 1:
The patent replaces complex mechanical sealing systems with a pressure-differential-driven flexible membrane system. The slit valve doors automatically seal under atmospheric pressure without requiring complex actuation mechanisms, reducing the number of mechanical steps involved in maintaining vacuum integrity during substrate transfer
Solution Approach 2:
The patent uses dynamically responsive flexible doors that automatically adjust their sealing force based on the pressure differential. The doors are more compliant during substrate transfer operations, allowing faster opening/closing while maintaining seal integrity, thereby improving substrate throughput without sacrificing vacuum reliability
3Ease of operation
If slit valve doors are positioned above the substrate transfer plane, then substrate access is easier, but sealing effectiveness decreases due to pressure differential
Solution Approach 1:
The patent inverts the conventional approach by positioning the seal surface perpendicular to the pressure differential rather than parallel to it. The slit valve doors seal against the chamber wall in a direction that maximizes the effect of atmospheric pressure pressing the flexible material against the seal surface, thereby achieving effective sealing even with doors positioned for easy substrate access
4Reliability
If atmospheric pressure is used to press doors against internal surfaces, then vacuum integrity is maintained without breaking vacuum in transfer chambers, but the door structure must withstand significant pressure differential
Solution Approach 1:
The patent uses flexible slit valve doors made of thin film materials that can withstand and utilize the pressure differential. The flexibility allows the doors to deform under atmospheric pressure to maintain sealing contact without requiring thick, heavy structural components, thereby achieving both vacuum integrity and reasonable structural strength
Solution Approach 2:
The patent converts the potentially harmful atmospheric pressure that could damage door structures into a beneficial sealing force. By orienting the seal surface perpendicular to the pressure differential, the atmospheric pressure presses the flexible doors against the chamber wall, enhancing the seal while the flexible material distributes the stress to prevent structural failure
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 enables seamless transfer of substrates between vacuum and atmospheric pressure environments without breaking vacuum, enhancing substrate throughput and reducing leaks, thus improving the efficiency and reliability of semiconductor processing systems.
Implementation Method 1
The atmospheric pressure presses the doors against the inside surface
Implementation Method 2
The atmospheric pressure from the factory interface side helps press the door against the outside surface
Data Source
AI summary
The present invention generally provides a load lock chamber having slit valve doors. The load lock chamber is used to connect a transfer chamber to a factory interface, or to connect two transfer chambers. When the load lock chamber is between adjacent transfer chambers, the load lock chamber has slit valve doors within the load lock chamber which seal against an inside surface of the load lock chamber. The load lock can thus be serviced at atmospheric pressure without breaking vacuum in the transfer chambers because the atmospheric pressure presses the doors against the inside surface. When the load lock chamber is between a transfer chamber and a factory interface, one slit valve door is disposed outside of the load lock chamber and seals against an outside surface of the load lock chamber. The atmospheric pressure from the factory interface side helps press the door against the outside surface.