Nozzle Surface Roughness for IPA Retention in Substrate Drying
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Solution Overview
Problem
In semiconductor fabrication, the use of smooth nozzles for discharging isopropyl alcohol (IPA) leads to IPA remaining in the nozzle and flowing down onto the substrate, delaying complete drying and affecting the yield of semiconductor elements due to the IPA's low surface tension and high volatility.
Innovation Solution
A discharging device with a nozzle featuring surface roughness on its inner surface is employed to increase the adhesive force between the nozzle and IPA, preventing IPA from flowing down by forming a pattern that enhances the surface roughness, typically within a range of 0.4 to 5 Ra, thereby optimizing the contact angle and reducing IPA leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth nozzle is used to discharge IPA, then the discharge process is simple and easy to manufacture, but IPA remains in the nozzle and flows down onto the substrate, delaying complete drying and affecting yield
Solution Approach 1:
The patent applies local quality by creating surface roughness only on the inner surface of the nozzle where IPA contact occurs, while maintaining a smooth outer surface for easy manufacturing. The roughness is concentrated in the specific region where the chemical discharge interface is located, providing localized functional improvement without compromising overall manufacturability.
Solution Approach 2:
The patent changes the surface roughness parameter of the nozzle inner surface from smooth (low roughness value) to rough (high roughness value within 0.4-5 Ra range). This parameter modification increases the adhesive force between the nozzle surface and IPA, preventing IPA from flowing down while maintaining reasonable manufacturability.
2Reliability
If surface roughness is added to the nozzle inner surface, then IPA adhesive force increases and flowing down is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the surface roughness parameter to a specific range (0.4-5 Ra) that provides sufficient adhesive force to prevent IPA flowing down while remaining achievable through conventional manufacturing techniques. This parameter optimization balances functional performance with manufacturing feasibility.
Solution Approach 2:
The roughness treatment is applied only to the inner surface of the nozzle where IPA contact occurs, rather than the entire nozzle structure. This localized approach minimizes the increase in manufacturing complexity while achieving the desired functional improvement.
3Reliability
If IPA is discharged completely from the nozzle, then substrate drying is improved, but IPA leakage and flowing down occur due to low surface tension
Solution Approach 1:
The patent converts the harmful effect of IPA's low surface tension (which causes it to flow down) into a beneficial effect by using surface roughness to increase adhesive force. The rough surface creates capillary action that holds the IPA in place, transforming the problematic low surface tension property into a means of preventing leakage.
Solution Approach 2:
The rough inner surface of the nozzle acts as an intermediary between the discharged IPA and the substrate. It mediates the interaction by increasing adhesive force to prevent IPA from flowing down, while still allowing complete discharge to occur for proper substrate drying.
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 surface roughness on the nozzle's inner surface effectively increases the adhesive force, preventing IPA from flowing down and ensuring complete drying of the substrate, thus improving the yield and quality of semiconductor elements by maintaining the IPA within the nozzle after discharge.
Implementation Method 1
A discharging device with a nozzle featuring surface roughness on its inner surface is employed to increase the adhesive force between the nozzle and IPA, preventing IPA from flowing down
Implementation Method 2
forming a pattern that enhances the surface roughness, typically within a range of 0.4 to 5 Ra, thereby optimizing the contact angle and reducing IPA leakage
Data Source
AI summary
According to at least one example embodiment, a substrate treating apparatus includes a substrate support structure including a spin head, the substrate support structure configured to support a substrate, and rotate the substrate, at least one treating liquid recovery container configured to recover at least one substrate treating liquid, and a discharging device including a first nozzle and a second nozzle, the first nozzle configured to discharge a chemical onto the substrate, and the second nozzle configured to discharge deionized water onto the substrate, wherein the first nozzle includes a surface pattern configured to provide roughness on an inner surface of the first nozzle.