Movable Blocking Element for EUV Projection Exposure Apparatus
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Solution Overview
Problem
The existing projection exposure apparatuses for microlithography face challenges in minimizing the cleanup effort and contamination when spectral filters, used to suppress unwanted radiation, are destroyed, especially in ultrahigh vacuum environments where access is difficult.
Innovation Solution
A movable blocking element is introduced that can be actuated by a sensor device to move into a barrier position upon detection of filter damage, preventing contamination from spreading to harder-to-reach regions, utilizing an actuator for rapid movement and a bearing device for frictionless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spectral filter is used to suppress unwanted radiation, then radiation purity is improved, but contamination risk increases when the filter is destroyed
Solution Approach 1:
A blocking element is positioned in advance in the beam path upstream of the spectral filter. Upon detection of filter destruction by a sensor device, this pre-positioned blocking element is actuated to close off the beam path, preventing contamination from spreading to harder-to-reach regions before cleanup is performed.
Solution Approach 2:
The blocking element serves as an intermediary protective component between the spectral filter and the rest of the projection exposure apparatus. When the filter fails, the blocking element intercepts and contains the harmful radiation and debris, acting as a mediator that protects downstream components from contamination.
2Manufacturing precision
If the projection exposure apparatus is operated in ultrahigh vacuum environment, then imaging precision is improved, but cleanup difficulty increases when contamination occurs
Solution Approach 1:
The beam path is segmented into distinct zones by the blocking element. The blocking element creates a separable boundary that allows contamination to be contained in a specific segment (upstream region) while protecting other segments (downstream regions) from contamination, enabling targeted cleanup efforts.
Solution Approach 2:
The blocking element extracts or removes the harmful contaminants from the main beam path by intercepting them upstream. This extraction of contaminants prevents them from reaching and contaminating the harder-to-reach regions, effectively separating the contamination problem from the sensitive imaging components.
3Ease of repair
If a blocking element is added to prevent contamination spread, then cleanup effort is reduced, but device complexity increases
Solution Approach 1:
The blocking element is designed to be movable rather than fixed, allowing it to be actuated between an open position (during normal operation) and a closed position (when filter destruction is detected). This dynamic capability enables the system to maintain simplicity during normal operation while providing enhanced protection when needed.
Solution Approach 2:
The sensor device automatically detects filter destruction and triggers the actuation of the blocking element without requiring manual intervention. The system serves itself by autonomously responding to filter failure, reducing the need for complex control systems and manual monitoring while still providing effective contamination prevention.
Data Source
AI summary
A projection exposure apparatus for microlithography, in particular an EUV projection exposure apparatus, having a beam path along which propagates electromagnetic radiation with which the projection exposure apparatus is operated, and having at least one filter (55) arranged in the beam path, wherein the projection exposure apparatus furthermore comprises at least one sensor device for monitoring the filter, wherein at least one blocking element (60) is provided which is movable between a standby position and a bather position, and wherein the movement of the blocking element can be effected at least in a manner dependent on a signal of the sensor device. An associated method for operating an apparatus of this type is also disclosed.