Spin Coating Gas Injection for Polygonal Substrate Uniformity
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Solution Overview
Problem
Spin coating of polygonal substrates results in non-uniform film thickness due to turbulence and pressure differences at corners, which existing countermeasures fail to fully address, leading to thicker films at corners compared to circular regions.
Innovation Solution
A spin coating system with gas injection ports that inject gas onto the corner portions of polygonal substrates during rotation, increasing pressure and preventing excessive coating material build-up, thereby achieving uniform film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spin coating is performed on polygonal substrates using conventional methods, then the coating process is simple and economical, but the film thickness becomes non-uniform with excessive build-up at corners
Solution Approach 1:
The patent applies local quality by introducing gas injection specifically at corner regions where thickness non-uniformity occurs. The gas injection ports are positioned to target only the corner areas, creating localized pressure increases that prevent excessive coating build-up at these specific locations without affecting other regions of the substrate.
Solution Approach 2:
The patent utilizes pneumatics by injecting gas into the process chamber at corner regions during spin coating. This gas injection creates localized pressure increases that counteract the pressure drop and turbulence at corners, thereby preventing excessive coating material accumulation and achieving uniform film thickness.
2Manufacturing precision
If high rotation speed is used for spin coating, then coating uniformity on circular substrates is achieved, but corner regions of polygonal substrates experience higher velocity causing pressure drop and turbulence
Solution Approach 1:
The patent applies preliminary anti-action by injecting gas into the corner regions before excessive coating build-up can occur. The gas injection creates a counteracting pressure increase that prevents the pressure drop and turbulence from taking effect, thereby stopping the harmful suction of coating material at corners before it can cause non-uniform thickness.
3Manufacturing precision
If gas injection is applied to all regions of the substrate, then uniform pressure is achieved, but excessive gas usage occurs and coating uniformity is not specifically improved at corners
Solution Approach 1:
The patent applies local quality by positioning gas injection ports specifically at corner regions rather than distributing gas injection across the entire substrate. This localized approach targets only the areas where thickness non-uniformity occurs, minimizing gas consumption while effectively preventing excessive coating build-up at corners.
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 system ensures substantial uniformity of the coating material thickness across the substrate surface, improving upon conventional technologies by maintaining at least 90% coverage and preventing excessive film build-up at corners.
Implementation Method 1
injecting a gas onto corner portions of the front surface of the substrate that are located along the reference ring as the substrate rotates about the rotational axis
Implementation Method 2
The combination of turbulence and lower pressure has the effect of 'sucking up' the polymer film at the corners
Implementation Method 3
rotating the substrate about a rotational axis to form a film of the coating material that substantially covers the front surface of the substrate
Data Source
AI summary
A spin coating apparatus, system, and/or method that increase the uniformity of a coating material on a substrate. The spin coating system may be specifically directed for use with polygonal shaped substrates. The spin coating system may include a process chamber within which the substrate is located, spinning on a chuck, during operation. The spin coating system may include gas injection ports that inject a gas into the process chamber so that the gas contacts the substrate along corner portions of its front surface. This injection of the gas increases pressure and prevents excessive build-up of the coating material that may otherwise occur when spin coating polygonal shaped substrates.