Predictive Spectral Control of Pulsed Light Beams
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Solution Overview
Problem
Existing lithography systems face challenges in achieving precise control over the spectral features of light beams, particularly wavelength and bandwidth, which are crucial for multi-focal imaging and complex 3D structure formation in semiconductor fabrication, leading to inconsistencies in etch and deposition results.
Innovation Solution
A predictive control apparatus with a spectral feature actuator and controller that adjusts the light beam's spectral features, such as wavelength and bandwidth, using a control waveform that transitions between discrete states, incorporating predictive modules for real-time corrections and feedback mechanisms to ensure accurate spectral feature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional control methods are used for light beam spectral features, then the system structure is simple, but the manufacturing precision and repeatability of spectral features deteriorate
Solution Approach 1:
The predictive module computes the control waveform in advance based on the desired spectral feature trajectory and actuator dynamics model, preparing the control signal before the actual spectral feature adjustment is needed. This preliminary computation enables precise spectral feature control without requiring complex real-time feedback adjustments during operation.
Solution Approach 2:
The feedback module receives sensed aspects of the spectral feature actuator and the predictive module uses this feedback information to adjust the control waveform, creating a closed-loop control system. This feedback mechanism compensates for disturbances and errors, improving spectral feature precision while maintaining manageable system complexity through intelligent control algorithms.
2Reliability
If spectral feature control is not dynamically adjusted, then the control system is simple, but the repeatability and consistency of light beam output deteriorate
Solution Approach 1:
The predictive module pre-computes the control waveform considering the actuator's dynamic characteristics and the desired spectral feature trajectory. This advance preparation ensures that the spectral feature reaches the target value accurately and on time, improving process reliability without requiring complex real-time adjustments.
Solution Approach 2:
The feedback module continuously monitors the actuator state and provides information to the predictive module, which adjusts the control waveform accordingly. This closed-loop approach compensates for disturbances and maintains consistent spectral feature output, enhancing reliability while keeping the control architecture manageable through systematic feedback processing.
3Manufacturing precision
If the control waveform is not adjusted in real-time, then the control system is simple, but the ability to compensate for disturbances and errors deteriorates
Solution Approach 1:
The feedback module receives sensed aspects of the spectral feature actuator and provides this information to the predictive module, which adjusts the control waveform in real-time. This feedback mechanism enables the system to compensate for disturbances and errors, maintaining spectral feature accuracy without requiring overly complex control algorithms through systematic error correction.
Solution Approach 2:
The predictive module pre-computes the control waveform based on the desired spectral feature trajectory and actuator dynamics, preparing the control signal in advance. This preliminary action, combined with feedback adjustments, enables precise spectral feature control while managing algorithmic complexity through structured predictive computation.
Data Source
AI summary
In some general aspects, a light beam control apparatus includes: a spectral feature actuator associated with a set of different states, each state configured to cause an optical apparatus to generate one or more pulses of a light beam at a discrete value of a spectral feature of the light beam; and a controller in communication with the spectral feature actuator. The controller includes: an actuator drive module configured to cause the spectral feature actuator to transition among the set of different states according to a control waveform; a waveform module configured to compute the control waveform for the spectral feature actuator that governs the transition among the set of discrete values; and a predictive module configured to receive one or more sensed aspects of the spectral feature actuator and instruct the waveform module to adjust the control waveform based on the received sensed aspects.