Liquid Processing Apparatus for Water Mark Prevention
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Solution Overview
Problem
Existing liquid processing methods for semiconductor wafers and glass substrates face challenges in completely removing minute water droplets, leading to water marks due to the expansion of dry regions from the center to the periphery, which is problematic as integrated circuits become more miniaturized.
Innovation Solution
A method involving a liquid processing apparatus that forms a stripe-shaped flow of rinse solution on the substrate by controlling the rotation speed and flow rate of the rinse solution, allowing the solution to move from the center to the periphery, effectively absorbing any remaining water droplets and preventing water marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inert gas nozzle and pure water nozzle are moved toward periphery of substrate from central portion, then dry region is expanded from center to periphery in concentric shape, but minute water drops remain on substrate surface and cannot be removed, causing water marks
Solution Approach 1:
The patent segments the drying process into two distinct phases: first expanding a dry region from the center to remove bulk water, then forming a liquid film flow to remove remaining minute water drops. This segmentation allows each phase to address specific aspects of water removal without compromising the other, thereby preventing water marks while maintaining drying efficiency.
Solution Approach 2:
The patent applies preliminary action by first expanding the dry region from the center before addressing the remaining minute water drops. This preliminary drying step prepares the substrate surface by removing the majority of water, making the subsequent liquid film flow more effective at removing residual drops that would otherwise cause water marks.
2Manufacturing precision
If pure water nozzle supplies pure water to form liquid film on substrate surface, then rinsing is performed, but minute water drops remain and are dried causing water marks
Solution Approach 1:
The patent ensures continuity of useful action by seamlessly transitioning from the rinsing process to the drying process. The liquid film flow continues to move across the substrate surface after the inert gas drying, ensuring that any minute water drops remaining after rinsing are continuously removed during the drying phase, preventing water mark formation.
Solution Approach 2:
The patent introduces a liquid film flow as an intermediary mechanism between the rinsing and final drying processes. This liquid film acts as a mediator that picks up minute water drops from the substrate surface and transports them to the periphery, preventing direct drying of isolated water drops that would cause water marks.
3Productivity
If substrate is rotated at high speed during rinsing, then rinsing efficiency is improved, but remaining water drops are not removed and water marks form
Solution Approach 1:
The patent applies dynamics by adjusting the substrate rotation speed according to the processing phase. During rinsing, high rotation speed is used to achieve good rinsing efficiency. During the subsequent drying phase, the rotation speed is reduced to allow the liquid film flow to effectively remove minute water drops without being dispersed by high centrifugal force, thereby preventing water marks.
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 ensures a clean drying of the substrate surface by controlling the flow and rotation speed of the rinse solution, preventing water marks and efficiently removing residual water droplets, even on miniaturized substrates.
Implementation Method 1
forming a liquid film of a rinse solution on an entire surface of a substrate having thereon a hydrophobic region by supplying, onto a central portion of the surface of the substrate, the rinse solution for rinsing a chemical liquid supplied on the substrate at a first flow rate while rotating the substrate at a first rotation speed
Implementation Method 2
forming a stripe-shaped flow of the rinse solution on the surface of the substrate by breaking the liquid film formed on the entire surface of the substrate
Implementation Method 3
forming a liquid film of a rinse solution on an entire surface of a substrate having thereon a hydrophobic region
Data Source
AI summary
A surface of a substrate can be dried cleanly after liquid-processed by a liquid processing method and a liquid processing apparatus. The liquid processing method includes forming a liquid film of a rinse solution on an entire surface of a substrate having thereon a hydrophobic region by supplying, onto a central portion of the surface of the substrate, the rinse solution for rinsing a chemical liquid supplied on the substrate at a first flow rate while rotating the substrate at a first rotation speed; forming a stripe-shaped flow of the rinse solution on the surface of the substrate by breaking the liquid film formed on the entire surface of the substrate; and moving a discharge unit configured to supply the rinse solution toward a periphery of the substrate until the stripe-shaped flow of the rinse solution is moved outside the surface of the substrate.