Porous Chuck Substrate Handling with Acoustic Touchdown Detection
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Solution Overview
Problem
Conventional lithography systems face challenges in handling substrates with varying thickness and focus issues, mechanical complexity, maintaining flatness, and detecting substrate touchdown without mechanical contact, which complicates high-resolution imaging across large areas.
Innovation Solution
The system employs porous chucks with pressure sources and vacuums to control air pressure and suction force independently for each optical path, allowing for precise focus adjustment and edge control, and uses acoustic signals for touchdown detection, ensuring non-contact handling and maintaining substrate flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vacuum chuck is used to hold substrate, then substrate can be held in place, but mechanical complexity increases and substrate flatness cannot be maintained for substrates with varying thickness
Solution Approach 1:
The patent replaces the conventional mechanical vacuum chuck system with an acoustic field-based holding system. Acoustic radiation pressure from ultrasonic transducers holds the substrate in place without mechanical contact, eliminating the mechanical complexity of vacuum chucks while maintaining substrate holding stability.
Solution Approach 2:
The patent uses acoustic radiation pressure, which is a form of fluid pressure (sound waves in air), to hold and position the substrate. The ultrasonic transducers create standing waves that exert radiation pressure on the substrate, providing contactless holding and positioning functionality.
2Manufacturing precision
If conventional mask-based lithography is used, then pattern can be transferred, but manufacturing time and cost increase significantly
Solution Approach 1:
The patent uses acoustic radiation pressure patterns as a dynamic, programmable mask alternative. Instead of physical masks that require fabrication time, the system creates patterns through controlled acoustic fields that can be changed electronically, providing instant pattern reconfiguration while maintaining lithographic precision.
Solution Approach 2:
The patent implements dynamic pattern generation through programmable ultrasonic transducer arrays. The acoustic radiation pressure patterns can be changed in real-time by modifying the drive signals to the transducers, enabling rapid pattern switching without the lead time required for physical mask fabrication.
3Device complexity
If single focus setting is used for imaging, then system is simple, but imaging resolution decreases across large substrates with thickness variations
Solution Approach 1:
The patent divides the substrate into multiple zones, each with its own dedicated ultrasonic transducer or transducer group. Each zone can be independently focused by adjusting the phase and amplitude of its corresponding transducers, allowing different focus settings for different regions of the substrate while maintaining overall system simplicity.
Solution Approach 2:
The patent implements local focus control by allowing each segment of the substrate to have optimized acoustic parameters. The ultrasonic transducers can be independently controlled to create localized focus points, ensuring high imaging resolution across the entire substrate even with thickness variations, while each local region maintains its own quality characteristics.
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 enables efficient, high-resolution imaging across large substrates with improved mechanical stability, reduced costs, and faster production by allowing dynamic focus adjustment and real-time monitoring, overcoming the limitations of conventional systems.
Implementation Method 1
a plurality of pressure sources configured to apply pressured air towards the substrate through the plurality of porous chucks
Implementation Method 2
a plurality of vacuums configured to apply suction force away from the substrate
Implementation Method 3
control logic configured to modulate each of the plurality of porous chucks with corresponding acoustic signals, control logic configured to sense the acoustic signals on a handler of the substrate
Data Source
AI summary
System and method for handling substrates in a lithography manufacturing process are disclosed. In one embodiment, a system for handling substrates in a lithography manufacturing process includes a plurality of porous chucks positioned above a substrate for imaging, a plurality of pressure sources configured to apply pressured air towards the substrate through the plurality of porous chucks, a plurality of vacuums configured to apply suction force away from the substrate, and a controller with control logic configured to hold the substrate in place by controlling the pressured air applied by the plurality of pressure sources and the suction force generated by the plurality of vacuums.