Substrate Cleaning Nozzle Control for Uniform Drying
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Solution Overview
Problem
In photolithographic processes, the uneven drying of substrates due to hydrophilic and hydrophobic regions leads to processing defects, such as water marks and residue from rinse liquids, which are difficult to remove using conventional spin drying methods.
Innovation Solution
A substrate cleaning method involving the controlled rotation and positioning of a substrate with a rinse liquid and gas nozzles to form a dry region at the substrate's center, allowing the rinse liquid to spread and be removed efficiently, while maintaining a stable boundary between the liquid and dry areas, ensuring uniform drying across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spin drying is used to remove rinse liquid from the substrate, then the hydrophobic portion is dried, but the hydrophilic portion retains rinse liquid droplets that cannot be removed by centrifugal force
Solution Approach 1:
The patent applies different drying methods to different regions of the substrate based on their hydrophilic or hydrophobic properties. The hydrophobic portion is dried by centrifugal force during spin drying, while the hydrophilic portion is dried by introducing a drying gas (such as nitrogen or clean air) to blow off the rinse liquid droplets. This localized quality approach ensures uniform drying across the entire substrate surface.
Solution Approach 2:
The patent introduces a drying gas as an intermediary substance to remove rinse liquid droplets from the hydrophilic portion of the substrate. The drying gas acts as a mediator between the rinse liquid droplets and the substrate surface, enabling effective removal of droplets that cannot be removed by centrifugal force alone.
2Manufacturing precision
If the rinse liquid is discharged onto the center of the rotating substrate, then the liquid layer spreads uniformly, but it is difficult to prevent droplet adhesion on hydrophilic portions during subsequent drying
Solution Approach 1:
The patent performs preliminary action by introducing the drying gas before the spin drying process completes. The drying gas is introduced onto the substrate surface while the substrate is still rotating, allowing the drying gas to act on the rinse liquid droplets on the hydrophilic portion before they can adhere firmly to the substrate. This preliminary drying action prevents droplet adhesion and subsequent processing defects.
Solution Approach 2:
The patent maintains continuous useful action by combining the rinse liquid discharge process with the drying gas introduction process. The drying gas is introduced continuously during the spin drying process, ensuring that the hydrophilic portion is dried throughout the entire drying period rather than as a separate step. This continuous action ensures uniform drying and prevents droplet adhesion.
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 method effectively prevents uneven drying and processing defects by ensuring reliable removal of rinse liquids from both hydrophilic and hydrophobic regions, maintaining substrate quality.
Implementation Method 1
rotating the substrate around an axis perpendicular to the substrate while substantially horizontally holding the substrate
Implementation Method 2
forming a dry region at the center of the substrate by discharging a gas onto the center of the substrate for a given period of time using a second nozzle that discharges the gas
Data Source
AI summary
A substrate rotates, and a liquid nozzle of a gas/liquid supply nozzle moves to a position above the center of the rotating substrate. In this state, a rinse liquid is discharged from the liquid nozzle onto the rotating substrate. The gas/liquid supply nozzle moves toward a position outside the substrate. A gas nozzle reaches the position above the center of the rotating substrate, so that the gas/liquid supply nozzle temporarily stops. With the gas/liquid supply nozzle stopping, an inert gas is discharged onto the center of the rotating substrate for a given period of time. After that, the gas/liquid supply nozzle again moves toward the position outside the substrate.