Lithographic Far Field Position Detector Alignment
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Solution Overview
Problem
In lithographic apparatuses, maintaining accurate alignment of the radiation source collector and illuminator is challenging due to mechanical shifts and misalignments over time, affecting the far field position and thereby the imaging performance and throughput.
Innovation Solution
A lithographic apparatus with a detector arrangement comprising a reflector and sensor system that measures the far field position by reflecting radiation from the source collector module and determining its location, allowing for realignment to ensure optimal positioning within specific boundaries, using a combination of one-dimensional and two-dimensional sensors to differentiate between translation and tilt-induced changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the collector is fixed in position to maintain stable radiation direction, then alignment stability is improved, but the ability to correct misalignment over time is worsened
Solution Approach 1:
The system transitions from a static fixed collector design to a dynamic system where the collector can be repositioned based on measured far field position. The detector arrangement provides feedback that enables dynamic adjustment of the collector position to maintain optimal alignment over time, resolving the contradiction between initial stability and long-term adaptability
Solution Approach 2:
A detector arrangement measures the far field position and provides feedback information about misalignment. This feedback loop enables the system to detect and correct alignment deviations, allowing the collector to be repositioned to maintain optimal radiation direction despite mechanical shifts or thermal expansion over time
2Device complexity
If the far field position is allowed to drift to simplify mechanical constraints, then device complexity is reduced, but imaging precision is worsened
Solution Approach 1:
The system replaces complex mechanical precision constraints with an optical measurement and correction system. Instead of relying solely on mechanical precision to maintain far field position, the patent uses a detector arrangement to measure position and enables correction through system reconfiguration, substituting mechanical complexity with optical feedback mechanisms
Solution Approach 2:
The system monitors changes in far field position parameters and enables correction by adjusting system parameters such as collector position or illuminator alignment. This allows the system to maintain imaging precision by dynamically adjusting parameters rather than relying on fixed mechanical constraints
3Manufacturing precision
If alignment checks are performed frequently to maintain precision, then manufacturing precision is improved, but productivity is worsened
Solution Approach 1:
The detector arrangement is integrated into the system to continuously or periodically monitor far field position without requiring full alignment procedures. This preliminary detection capability allows for quick verification and correction, maintaining precision while minimizing interruption to the lithographic process and preserving productivity
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 precise alignment of the source collector module and illuminator, improving the operating performance and imaging quality by accurately determining and correcting deviations in the far field position, thus enhancing the overall throughput of the lithographic process.
Implementation Method 1
a reflector arrangement disposed in a fixed positional relationship with respect to the illuminator, the reflector arrangement being arranged to reflect radiation from the source collector module
Implementation Method 2
a sensor arrangement disposed in a fixed positional relationship with respect to the reflector arrangement, the sensor arrangement being configured to measure at least one property of radiation reflected by the reflector
Data Source
AI summary
A lithographic apparatus comprising a source collector module including a collector, configured to collect radiation from a radiation source; an illuminator configured to condition the radiation collected by the collector and to provide a radiation beam; and a detector arrangement comprising a reflector arrangement disposed in a fixed positional relationship with respect to the illuminator, the reflector arrangement being arranged to reflect radiation from the source collector module; and a sensor arrangement disposed in a fixed positional relationship with respect to the reflector arrangement, the sensor arrangement being configured to measure at least one property of radiation reflected by the reflector, the detector arrangement being configured to determine the location of a far field position of the radiation as a function of at least one property of the radiation reflected by the reflector and measured by the sensor arrangement.