Lithographic Object Positioning via Fluid Pressure Compensation
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Solution Overview
Problem
Temperature variations and pressure gradients in lithographic apparatus conduit systems cause deformation of objects, leading to positioning errors and overlay errors during substrate patterning, which existing temperature conditioning systems fail to fully mitigate due to induced dynamic disturbances.
Innovation Solution
Incorporating a measurement system to detect fluid pressure within the conduit system and using a control system to adjust object movement based on pressure measurements or predictions, thereby compensating for deformation caused by pressure variations and improving positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a temperature conditioning system with fluid conduit is used to reduce object deformation, then temperature control and deformation reduction are improved, but pressure gradients during acceleration cause dynamic disturbance forces that adversely affect positioning accuracy
Solution Approach 1:
The control system predicts the pressure gradient and disturbance force before acceleration occurs, and pre-adjusts the object's position to compensate for the expected deformation. This preliminary action prevents positioning errors rather than correcting them after they occur.
Solution Approach 2:
The system uses sensors to measure actual pressure and temperature conditions in real-time, feeds this information back to the control system, which then adjusts the object's position dynamically. This closed-loop feedback ensures positioning accuracy is maintained despite changing pressure conditions during acceleration.
2Temperature
If fluid pressure is increased to improve temperature conditioning effectiveness, then temperature control is improved, but deformation caused by pressure variation increases reducing positioning accuracy
Solution Approach 1:
Pressure sensors continuously monitor the fluid pressure in the conduit system, and this pressure information is fed back to the control system. The control system uses this feedback to calculate and compensate for pressure-induced deformation, allowing effective temperature control without sacrificing positioning accuracy.
Solution Approach 2:
The system dynamically adjusts operational parameters including fluid pressure, temperature, and object position based on real-time measurements. By changing these parameters in a coordinated manner, the system maintains effective temperature conditioning while compensating for deformation to preserve positioning accuracy.
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 significantly reduces positioning errors and overlay errors by actively counteracting the effects of temperature conditioning system-induced deformations, enhancing the accuracy of object positioning in lithographic apparatuses.
Implementation Method 1
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 in a direction of acceleration of an object, a conduit system and fluid therein, causes a pressure gradient in the fluid opposite to the direction of acceleration
Implementation Method 3
This pressure gradient may excite a resonance mode of the fluid in the conduit system which can lead to the occurrence of pressure pulses within the conduit system
Data Source
AI summary
A temperature conditioning system for a lithographic apparatus. Temperature variations in an object cause object deformation which prevents the object being accurately positioned. Temperature condition systems use conduit systems, provided with fluid, in or on the object to control the temperature of the object to reduce object deformation. In this way, parts of the object can be more accurately positioned. However, acceleration of the object and the temperature conditioning system induces variation in pressure within the fluid inside the conduit system on or in the object, which may also cause object deformation. To provide an improved conduit system, the lithographic apparatus further includes a control system which is used to control the movement of the object based on measurements indicating pressure variation in the conduit.