Lithographic Patterning Device Tilt Gauge
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Solution Overview
Problem
In lithographic apparatuses, there is a need to accurately measure and correct the tilt of patterning devices during transfer to prevent damage and ensure precise alignment, as improper tilt can lead to inaccuracies and costs due to equipment damage, inefficient processing, and processing delays.
Innovation Solution
A patterning device alignment system utilizing a multipath sensory array with a collimating light path and detectors to calculate tilt parameters and X-Y planar location positions, employing a co-axial Kohler illumination source and beam splitters to provide pre-alignment measurements and trigger corrective actions, such as cancelling transfer operations if tilt thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional alignment methods are used without tilt measurement, then the system is simpler, but the patterning device may be damaged and alignment accuracy deteriorates
Solution Approach 1:
The system performs preliminary tilt measurements using the collimating light path and detectors before the patterning device is transferred to the electrostatic chuck. This advance detection allows the control system to prevent transfer operations that would result in damage, thereby protecting the patterning device without requiring complex real-time intervention mechanisms during transfer
Solution Approach 2:
A collimating light path with detectors is introduced as an intermediary measurement system between the patterning device and the electrostatic chuck. This intermediary system provides tilt information that mediates the transfer decision, enabling accurate alignment assessment without direct mechanical contact or complex integrated sensing in the transfer mechanism itself
2Manufacturing precision
If tilt measurement and correction systems are implemented, then alignment accuracy improves, but processing time increases due to additional measurements and potential cancellations
Solution Approach 1:
Tilt measurements are performed in advance during the pre-alignment stage before the main patterning process. By detecting tilt parameters early using the collimating light path, the system can either correct alignment issues or cancel problematic transfer operations before they affect production, thereby ensuring high alignment accuracy without significantly impacting overall processing throughput
Solution Approach 2:
The system implements feedback control by using detector measurements of the reflected collimated beam to determine tilt parameters. This feedback information is fed to the control system, which can then adjust alignment or cancel operations as needed, enabling precise alignment control while maintaining efficient processing through automated decision-making
3Measurement precision
If multiple detection channels are used for comprehensive measurements, then measurement precision improves, but device complexity increases
Solution Approach 1:
The measurement system is segmented into distinct functional components: a collimating light path for generating parallel beams, separate detectors for measuring beam displacement, and a control system for processing tilt parameters. This segmentation allows each component to be optimized independently for its specific function, achieving high measurement precision without requiring a monolithic complex system
Solution Approach 2:
The collimating light path serves multiple functions: it provides the illumination beam for measurement, acts as a reference for tilt detection, and enables the detectors to measure both position and tilt parameters. This multi-functionality reduces the need for separate dedicated components, thereby improving measurement precision while limiting the increase in overall device complexity
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 pre-alignment measurements, protecting the patterning device and electrostatic chuck, reducing errors, and enhancing processing efficiency by ensuring accurate device transfer and minimizing costs associated with damage and inefficiencies.
Implementation Method 1
a first collimating light path... receiving a reflected illumination beam from an illuminated patterning device
Implementation Method 2
receiving a reflected illumination beam from an illuminated patterning device
Implementation Method 3
one or more other light paths... receiving a second reflected illumination beam from a beam splitter
Data Source
AI summary
A patterning device alignment system including a multipath sensory array including a first collimating light path and one or more other light paths, a first detector positioned at a first end of the first collimating light path, and a second detector positioned at a first end of the one or more other light paths, the first detector configured to receive a reflected illumination beam from an illuminated patterning device and calculate a tilt parameter of the patterning device, and the second detector configured to receive a second reflected illumination beam from a beam splitter and calculate an X-Y planar location position and a rotation position of the patterning device.