Spin Coating Film Thickness Control via Dynamic Airflow
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Solution Overview
Problem
The thickness of liquid films formed on substrates during the photolithography process is inconsistent due to varying downward air flows caused by differences in pressure between the liquid-film forming apparatus and the surrounding chamber, making it difficult to achieve uniform film thickness across different substrates.
Innovation Solution
An apparatus and method that include liquid dispensing units and air-flow supply units controlled by a controller to adjust the amount and speed of downward air flows based on the amount of pre-treatment liquid dispensed, ensuring consistent film thickness by varying the air flow supply states to match the liquid film forming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant downward air flow is supplied in the liquid-film forming apparatus, then the coating solution volatilization is controlled, but the liquid film thickness becomes inconsistent due to pressure differences between chambers
Solution Approach 1:
The patent applies dynamics by making the air flow supply adjustable rather than constant. The air flow supply unit is configured to vary the downward air flow based on the type of liquid film being formed, allowing the system to adapt to different pressure conditions and liquid characteristics. This dynamic adjustment resolves the contradiction by enabling both reliable coating solution control and consistent liquid film thickness through variable air flow rates.
Solution Approach 2:
The patent changes the parameter of air flow rate to resolve the contradiction. By adjusting the air flow supply parameter according to the liquid film type and chamber pressure conditions, the system maintains both effective coating solution control and uniform liquid film thickness. The controller modifies air flow parameters dynamically based on process requirements.
2Ease of operation
If the air flow supply state is fixed after apparatus setup, then the apparatus operation is simple, but it cannot adapt to different liquid film forming requirements across multiple substrates
Solution Approach 1:
The patent implements dynamics by enabling the air flow supply unit to be adjusted for different liquid film types. The controller is programmed to automatically modify air flow parameters based on the specific coating requirements, allowing the apparatus to adapt to various substrates and liquids while maintaining ease of operation through automated control.
Solution Approach 2:
The patent applies feedback control where the controller monitors the liquid film forming process and adjusts the air flow supply accordingly. This feedback mechanism enables the system to adapt to different substrates and liquid characteristics automatically, maintaining both operational simplicity and high adaptability through closed-loop control.
3Strength
If different amounts of pre-treatment liquid are dispensed on different substrates, then the adhesion improvement varies, but the liquid film thickness becomes non-uniform
Solution Approach 1:
The patent changes the air flow parameter in response to variations in pre-treatment liquid amount. When different substrates require different pre-treatment liquid amounts for optimal adhesion, the controller simultaneously adjusts the air flow supply to compensate for the resulting liquid film thickness variations, maintaining both adhesion strength and film uniformity.
Solution Approach 2:
The patent applies preliminary anti-action by anticipating the effect of varying pre-treatment liquid amounts on film thickness. The controller pre-adjusts the air flow parameters before coating to counteract the expected thickness variations, ensuring uniform film formation even when adhesion requirements demand different pre-treatment liquid amounts.
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 allows for uniform adjustment of liquid film thickness and the ability to form different types of films to the same thickness on multiple substrates, improving the consistency and reliability of the liquid film forming process.
Implementation Method 1
air-flow supply units that are provided in the first and second process chambers and that form downward air flows in the first and second spaces, respectively
Implementation Method 2
an apparatus and method for forming a liquid film on a substrate by spin coating
Data Source
AI summary
The inventive concept relates to an apparatus and method for forming a film on a substrate by spin coating. The apparatus includes liquid dispensing units that dispense processing liquids to form liquid films on the first and second substrates, respectively, air-flow supply units that form downward air flows in the first and second spaces, respectively, and a controller that controls the liquid dispensing units and the air-flow supply units. Each of the liquid dispensing units includes a pre-treatment nozzle that dispenses a pre-treatment liquid and a coating solution nozzle that dispenses a coating solution onto a corresponding one of the first and second substrates. The controller controls the liquid dispensing units to dispense the pre-treatment liquids and thereafter the coating solutions onto the first and second substrates and adjusts supply states of the downward air flows according to amounts of the pre-treatment liquids dispensed.