Lithographic Apparatus Gas-Conditioned Environment Pressure Stabilization
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Solution Overview
Problem
Lithographic apparatuses face challenges in responding to short-term pressure fluctuations, leading to mechanical deformation of optical elements and degradation of imaging quality due to inadequate pressure stabilization between the gas-conditioned environment and the ambient atmosphere.
Innovation Solution
A lithographic apparatus with a gas-conditioned environment is designed to communicate with the ambient atmosphere through a controlled leakage system, using a gate to manage pressure differences and a suspension mount for the exit optical element to reduce mechanical stress, thereby stabilizing the optical system and improving imaging resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas conditioned environment is completely isolated from ambient atmosphere, then imaging quality is maintained, but pressure stabilization responds too slowly to sudden fluctuations
Solution Approach 1:
A gate valve is introduced as an intermediary component between the gas conditioned environment and ambient atmosphere. This valve enables controlled communication that allows rapid pressure equalization during fluctuations while maintaining isolation during normal operation, thus resolving the contradiction between maintaining imaging quality and achieving fast pressure response
Solution Approach 2:
The gate valve transitions the system from a static completely isolated state to a dynamic state where controlled communication can occur. This dynamic capability allows the system to adapt quickly to pressure fluctuations by opening the gate when needed, while maintaining isolation for imaging quality when the gate remains closed
2Reliability
If pressure stabilization system is designed to respond to pressure differences, then pressure fluctuations are corrected, but response time is too large for sudden fluctuations
Solution Approach 1:
The gate valve is pre-positioned in a ready state that allows rapid opening in response to pressure fluctuations. This preliminary preparation enables the system to respond immediately to sudden pressure changes without the delay associated with traditional pressure stabilization systems that must first detect and then activate correction mechanisms
3Stability of the object's composition
If exit optical element is rigidly mounted in housing, then structural stability is maintained, but mechanical deformation occurs under pressure differences
Solution Approach 1:
A flexible membrane is introduced as a mounting structure for the exit optical element. This membrane provides the necessary flexibility to accommodate pressure differences without causing mechanical deformation of the optical element, while still maintaining sufficient structural stability to hold the element in position and preserve imaging resolution
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
The solution effectively addresses short-term pressure fluctuations, preventing mechanical deformation and enhancing imaging quality and the lifespan of the projection system by maintaining a stable gas environment while allowing controlled communication with the ambient atmosphere.
Implementation Method 1
The gas conditioned environment is communicatively coupled to ambient atmosphere variations of the ambient atmosphere without contaminating the environment
Data Source
AI summary
A lithographic apparatus includes a projection system configured to project a patterned beam of radiation onto a target portion of a substrate. The projection system includes a first gas-conditioned sub-environment and a second gas-conditioned sub-environment. The apparatus includes a gas control unit configured to control the feeding of conditioned gas into the first sub-environment and into the second sub-environment via the first sub-environment so as to prevent contamination from the second sub-environment to the first sub-environment. The apparatus includes a gate configured to leak the conditioned gas at a rate from the second sub-environment to ambient atmosphere, and a detector configured to detect at least one property of the second gas-conditioned environment.