Capillary Coating Speed Control for Uniform Substrate Film Thickness
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Solution Overview
Problem
The capillary coating technique results in uneven film thickness on substrates, with the outer periphery regions having a thicker film compared to other areas.
Innovation Solution
A substrate processing apparatus and method that involves a holder, nozzle, and controller to move the nozzle and substrate relative to each other using capillary action, with a controlled speed based on the substrate's outer peripheral shape to maintain a consistent gap and adjust the moving speed accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If capillary coating technique is used to apply processing liquid to substrate, then the processing liquid can be discharged to the substrate with use of capillary action, but the thickness of film becomes larger in outer periphery portion than in other portions
Solution Approach 1:
The patent applies dynamics by making the moving speed variable rather than constant. The controller dynamically adjusts the moving speed of the nozzle relative to the substrate based on their relative positions, specifically increasing speed when approaching the outer periphery and decreasing speed in central regions. This dynamic speed adjustment compensates for the capillary action effect that causes thicker film formation at the outer periphery, thereby achieving uniform film thickness across the substrate surface.
2Productivity
If the nozzle is moved at constant speed over the substrate, then the coating process is simple, but the film thickness varies across different portions of the substrate
Solution Approach 1:
The patent applies parameter changes by modifying the moving speed parameter of the nozzle during the coating process. Instead of maintaining a constant speed, the controller changes the speed parameter dynamically based on the nozzle's position relative to the substrate, particularly adjusting speed in response to the substrate's outer peripheral shape. This parameter change enables both maintained productivity through continuous movement and improved film thickness control through position-dependent speed variation.
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 suppresses variations in film thickness by ensuring consistent application of the processing liquid across the substrate, particularly at the outer periphery regions.
Implementation Method 1
cause a processing liquid to be discharged from the discharge port of the nozzle to the main surface of the substrate with use of capillary action
Data Source
AI summary
A substrate processing apparatus includes a holder that holds a substrate, a nozzle having a bottom portion in which a discharge port extending in one direction is formed, a mover that, above the substrate held by the holder, relatively moves at least one of the nozzle and the substrate with respect to another one in an intersecting direction that intersects with the one direction with a gap equal to or smaller than a predetermined distance provided between the bottom portion of the nozzle and the main surface of the substrate in order to cause a processing liquid to be discharged from the discharge port of the nozzle to the main surface of the substrate with use of capillary action, and a controller that controls the mover and relatively moves the nozzle and the substrate at a moving speed determined based on an outer peripheral shape of the substrate.