Slit Coater Solution Supply System for Uniform Large Substrate Coating
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Solution Overview
Problem
Existing coating methods, such as spin coating, are inadequate for large and heavy substrates like flat panel display devices, as they struggle with uniformity, energy consumption, and waste of photosensitive solution, leading to contamination and environmental issues.
Innovation Solution
A slit coater apparatus that uses a slit nozzle to apply a uniform layer of photosensitive solution onto substrates, with a supply system including a storage tank, pump, and buffer tank to maintain pressure and remove bubbles, allowing for efficient and precise coating without the need for high-speed rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spin coating method is used to achieve high precision coating uniformity and thickness control, then manufacturing precision is improved, but it becomes unsuitable for large and heavy substrates due to difficulty in high-speed rotation and increased energy consumption
Solution Approach 1:
The patent replaces the mechanical spin coating system with a slit coater that uses a moving table and controlled coating head to apply photoresist. This eliminates the need for high-speed substrate rotation, making the process suitable for large and heavy substrates while reducing energy consumption and avoiding mechanical stress on the substrate
Solution Approach 2:
The coating process is segmented into distinct phases: initial coating application, intermediate drying, and final drying. This segmentation allows for controlled coating without requiring continuous high-speed rotation, enabling processing of large substrates while maintaining coating uniformity
2Manufacturing precision
If spin coating method is used for high precision pattern formation, then manufacturing precision is improved, but a large amount of photosensitive solution is wasted due to dispersion outside the spin chuck
Solution Approach 1:
The slit coater replaces the spin coating mechanism with a controlled dispensing system that applies photoresist only where needed on the substrate. This eliminates the radial dispersion of solution that occurs in spin coating, significantly reducing waste while maintaining precise pattern formation capability
Solution Approach 2:
The coating head applies photoresist locally to specific regions of the substrate rather than coating the entire surface uniformly. This localized application reduces overall solution usage and waste while achieving the required coating precision for pattern formation
3Area of stationary object
If high-speed rotation is applied to coat large substrates using spin coater, then coating coverage is improved, but damage to the substrate can occur
Solution Approach 1:
The patent replaces the high-speed rotation mechanism with a linear moving table system that transports the substrate through the coating zone. This eliminates centrifugal forces and mechanical stress on the substrate while achieving complete coating coverage through controlled movement and multiple coating passes
4Ease of operation
If spray coating method or roll coating method is used, then ease of operation is improved, but high precision in coating film uniformity and thickness adjustment cannot be achieved
Solution Approach 1:
The coating head and table are designed with dynamic control capabilities, allowing precise adjustment of coating speed, dispensing rate, and head-to-substrate distance. This dynamic control enables precise thickness adjustment and uniform coating while maintaining operational simplicity through automated control
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 slit coater provides a uniform coating on large substrates with reduced solution waste and minimized contamination, improving the precision and efficiency of the photolithography process while preventing environmental pollution.
Implementation Method 1
a pump that supplies the coating solution stored in the storage tank to the slit nozzle unit
Implementation Method 2
a buffer tank in fluid communication with the pump and the storage tank, wherein the supply apparatus substantially uniformly maintains pressure of the pump and removes bubbles from the coating solution
Data Source
AI summary
A slit coater including an apparatus for supplying coating solution by a coating method using a slit nozzle, which is configured to minimize contamination of coating solution, utilizing a filtering function, and supplying a controlled amount of photosensitive solution to a slit nozzle. The slit coater further includes a table on which an object to be processed is mounted, a slit nozzle unit that applies coating solution onto a surface of the object to be processed, and a coating solution supply apparatus including a storage tank that stores the coating solution, a pump that supplies the coating solution stored in the storage tank to the slit nozzle unit, and a buffer tank that is in fluid communication with the pump and the storage tank.