Optical Coating Coverage Control for Precision Liquid Dispensing
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Solution Overview
Problem
Conventional semiconductor manufacturing processes dispense excessive amounts of liquid materials to ensure complete coverage on substrates due to variability in dispense systems, photoresist composition, substrate surface properties, and topography, leading to waste and inefficiency.
Innovation Solution
A method using laser beams to monitor scattered and reflected light from a substrate during liquid dispensing, allowing real-time adjustment of dispense operations to ensure precise coating without excess material, by tracking the liquid's progression and adjusting rotational velocity or dispense volume based on light behavior analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess liquid is dispensed to ensure full coverage, then coverage reliability is improved, but material waste increases
Solution Approach 1:
The system uses optical sensors to detect the leading edge of the liquid in real-time during dispensing, feeds this information back to the controller, which then dynamically adjusts the dispensing parameters to achieve complete coverage with minimal excess material
Solution Approach 2:
The system performs preliminary detection of substrate position and liquid flow characteristics before complete dispensing, allowing optimization of dispensing parameters in advance to prevent both over-dispensing and under-dispensing
2Manufacturing precision
If real-time monitoring is implemented, then dispensing precision is improved, but system complexity increases
Solution Approach 1:
The patent introduces optical sensors as intermediaries to detect liquid position and substrate characteristics, translating physical phenomena into measurable signals that enable precise control without requiring complex direct measurement systems
Solution Approach 2:
The system replaces complex mechanical measurement and adjustment mechanisms with optical detection and electronic control, using light-based sensing to monitor liquid dispensing and automate parameter adjustments
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
Reduces waste by minimizing excess liquid dispensed by up to 98%, enhances process efficiency, and reduces tool downtime through real-time feedback control.
Implementation Method 1
monitoring scattered light from the first laser beam directed at the edge of the working surface of the substrate
Implementation Method 2
monitoring scattered light or reflected light from the second laser beam directed at the interior portion of the working surface of the substrate
Implementation Method 3
the resist solution spreads radially across the substrate due to centrifugal forces imposed by the substrate rotation
Data Source
AI summary
Light can be used to monitor coating a liquid on a substrate. By directing the light to a spot on the substrate, when the liquid passes through the spot, some light will be reflected, while some light will be scattered. Monitoring this behavior can indicate whether a substrate has been successfully coated with the liquid, as well as identifying defects. Further, coating times can be monitored to make process adjustments.