Spiral Coating Nozzle with Variable Ejection for Film Uniformity
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in achieving uniform film thickness due to variations in the ejection amount of processing liquid across the substrate's circumference, particularly at the outermost periphery, leading to differences in film thickness.
Innovation Solution
A substrate processing apparatus with a rotary holder, liquid supplier, and driver, controlled by a controller to supply processing liquid in a spiral trajectory, gradually reducing the ejection amount per unit area at the outermost periphery, using a combination of flow rate adjustment and pressure control to ensure uniform film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the processing liquid is supplied in a spiral trajectory with constant ejection amount, then the coating process can be completed efficiently, but the film thickness becomes non-uniform at the outermost periphery
Solution Approach 1:
The patent applies local quality by varying the ejection amount of processing liquid based on the radial position on the substrate. Specifically, the ejection amount is reduced in the outer peripheral region compared to the central region, creating a position-dependent liquid supply strategy that compensates for the naturally higher liquid accumulation at the periphery during spiral coating
Solution Approach 2:
The patent changes the parameter of ejection amount dynamically during the coating process. By adjusting the ejection amount as a function of radial position (reducing it towards the outer periphery), the system transforms from a constant supply mode to a variable supply mode, achieving uniform film thickness across different regions of the substrate
2Manufacturing precision
If the ejection amount is reduced at the outermost periphery, then film thickness uniformity is improved, but the complexity of the control system increases
Solution Approach 1:
The patent implements feedback control by using a sensor to detect the actual film thickness or liquid distribution on the substrate and adjusting the ejection amount accordingly. The controller receives information about the coating state and modifies the ejection amount in real-time to achieve the desired uniformity, creating a closed-loop control system
Solution Approach 2:
The patent introduces dynamic control of the ejection amount, transitioning from a static constant ejection mode to a dynamic variable ejection mode. The ejection amount is continuously adjusted during the coating process based on radial position and/or real-time feedback, making the system adaptable to varying coating conditions
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 significantly reduces differences in film thickness across the substrate's circumference, improving the uniformity of the film formed on the substrate surface, especially when processing high viscosity liquids.
Implementation Method 1
a nozzle that ejects a processing liquid, and supplies the processing liquid to a surface of a substrate
Data Source
AI summary
A substrate processing apparatus includes: a rotary holder configured to hold and rotate a substrate; a liquid supplier including a nozzle that ejects a processing liquid; a driver configured to move the nozzle between a center of the substrate and a peripheral portion of the substrate; and a controller configured to: execute a supply control to supply the processing liquid to the surface of the substrate so as to form a supply trajectory in a spiral shape, by ejecting the processing liquid from the nozzle while rotating the substrate and moving the nozzle from the center of the substrate toward the peripheral portion of the substrate; and when executing the supply control, gradually reduce an ejection amount of the processing liquid per unit area on the surface of the substrate, at least in a portion forming an outermost periphery of the supply trajectory.