DUV Laser Bandwidth Control via Coarse Fine Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current passive bandwidth stabilization techniques in DUV gas discharge laser systems are insufficient to meet future tighter Optical Proximity Effect (OPE) specifications, requiring advanced active control methods to stabilize and regulate the E95 bandwidth within a narrow range.
Innovation Solution
A line-narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control system employing a bandwidth metrology module, error signal generator, and active spectral controller with fine and coarse actuators to dynamically adjust the laser's bandwidth, using algorithms like E95 feedback and dither control to maintain stability and setpoint regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If passive bandwidth stabilization techniques are used, then the system structure remains simple, but the bandwidth control precision is insufficient to meet tighter OPE specifications
Solution Approach 1:
The patent implements active feedback control by continuously measuring the laser bandwidth with a spectrometer and adjusting control parameters (discharge timing, gas flow rates, capacitor bank settings) based on the measured bandwidth to maintain it within the specified range, thereby achieving precise bandwidth control that meets tighter OPE specifications
Solution Approach 2:
The patent dynamically adjusts multiple operating parameters including discharge timing delays between chambers, fluorine gas flow rates, and capacitor bank discharge energies to actively control and stabilize the laser bandwidth, enabling precise regulation of the optical properties to meet manufacturing precision requirements
2Stability of the object's composition
If active spectral control with multiple actuators is implemented, then bandwidth stability is improved, but the device complexity increases
Solution Approach 1:
The patent divides the laser system into multiple independently controllable chambers (oscillator chamber and amplifier chambers) with separate discharge timing and gas flow control, allowing individual optimization of each segment's contribution to the overall bandwidth stability while managing complexity through modular control
Solution Approach 2:
The control system performs multiple functions using integrated actuators: discharge timing control affects both bandwidth and pulse energy, gas flow control influences both bandwidth and laser efficiency, and capacitor bank settings affect both bandwidth and output power, allowing a single actuator to manage multiple parameters simultaneously
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 system effectively stabilizes and regulates E95 bandwidth, improving OPE control by reducing variability and allowing dynamic setpoint selection, thereby enhancing the precision and reliability of micro-photolithography processes.
Implementation Method 1
a bandwidth metrology module measuring the bandwidth of a laser output light pulse beam pulse produced by the light source and providing a bandwidth measurement
Implementation Method 2
an active spectral controller providing a fine bandwidth correction actuator signal and a coarse bandwidth correction actuator signal responsive to the bandwidth error
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
A line narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control system comprising: a bandwidth metrology module measuring the bandwidth of a laser output light pulse beam produced by the light source and providing a bandwidth measurement; a bandwidth error signal generator receiving the bandwidth measurement and a bandwidth setpoint and providing a bandwidth error signal; a multi-stage actuator system comprising: a coarse bandwidth correction actuator adapted to induce a first modification of the light source that influences the bandwidth of the laser output light pulse beam and targeting large amplitude disturbances occurring at low frequency; a fine bandwidth correction actuator adapted to induce a second modification of the light source that influences the bandwidth of the laser output light pulse beam and targeting small amplitude disturbances occurring at high frequency; an active bandwidth controller providing a fine bandwidth correction actuator signal to said fine bandwidth correction actuator and a coarse bandwidth correction actuator signal to said coarse bandwidth correction actuator responsive to the bandwidth error signal.