Lithography Conduit Pattern for Disturbance Reduction
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Solution Overview
Problem
Lithographic apparatuses face positioning accuracy issues due to temperature control methods that introduce disturbances through fluid flow, exciting standing wave modes in conduits and causing significant disturbance forces, particularly when these modes resonate within critical frequency ranges that control systems cannot compensate for.
Innovation Solution
The apparatus features a conduit pattern on or within the object that ensures the acceleration pressure profile in the fluid does not match the resonance pressure profile of standing wave modes within the frequency range of interest, minimizing disturbances by potentially shortening conduit length, using multiple conduits, or adjusting fluid properties to shift resonance frequencies outside the critical range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conduit is arranged on or in the object for temperature control using fluid flow, then temperature control is achieved, but acceleration of the object causes pressure gradients in the fluid that excite standing wave modes and create disturbance forces on the object
Solution Approach 1:
The conduit is arranged in an asymmetric pattern on or in the object such that the acceleration pressure profile does not match the resonance pressure profile of standing wave modes. This asymmetric configuration prevents resonant excitation of fluid modes during acceleration, thereby reducing disturbance forces while maintaining temperature control functionality.
Solution Approach 2:
The invention changes the spatial arrangement parameter of the conduit from conventional symmetric or linear configurations to specific asymmetric patterns. This parameter change modifies the fluid's acceleration pressure profile to avoid matching resonance conditions, thereby eliminating the harmful standing wave effects during object acceleration.
2Stability of the object's composition
If the conduit is arranged in a conventional pattern for temperature control, then temperature uniformity is achieved, but standing wave modes are excited during acceleration causing positioning errors in the frequency range of interest
Solution Approach 1:
The conduit follows an asymmetric pattern designed to decouple the acceleration pressure profile from resonance pressure profiles of standing wave modes. This asymmetric arrangement prevents excitation of fluid modes during acceleration, thereby maintaining positioning accuracy in the critical frequency range while still providing effective temperature control.
Solution Approach 2:
The conduit pattern is locally optimized at different positions on or in the object to achieve both temperature uniformity and avoidance of resonant frequencies. The local arrangement of the conduit varies along its path to ensure temperature distribution while preventing standing wave mode excitation during acceleration.
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 approach enhances the positioning accuracy of objects in lithographic apparatuses by reducing disturbances caused by fluid flow, allowing for effective temperature control without compromising the precision required in critical frequency ranges.
Implementation Method 1
a conduit being arranged on or in the object and being configured to receive a fluid within the conduit, such that the fluid can be used to transport heat from or to the object depending on the thermal condition of the object
Implementation Method 2
acceleration of the object, conduit and fluid therein in a direction of acceleration causes a pressure gradient in the fluid in the direction of acceleration
Implementation Method 3
This pressure gradient may excite standing wave modes in the conduit. The excited standing wave modes may result in a significant disturbance force on the object
Data Source
AI summary
A lithographic apparatus includes: an object that is moveable in at least one direction; a control system to move the object in the at least one direction, wherein the control system is arranged to control movement of the object in the at least one direction in a frequency range of interest; and a conduit provided with a fluid, wherein the conduit is arranged on or in the object in a pattern, and wherein the pattern is such that an acceleration of the object in the at least one direction causes an acceleration pressure profile in the fluid along the conduit, the acceleration pressure profile not matching with a resonance pressure profile that corresponds to a standing wave mode in the fluid with a resonance frequency in the frequency range of interest.