Substrate Rinsing via Deceleration and Puddle Formation
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Solution Overview
Problem
Existing substrate treatment methods fail to ensure complete coverage of the substrate surface with a puddle-like rinse liquid film, particularly when the substrate surface is hydrophobic or uneven, leading to exposure and inefficiencies in chemical liquid removal and drying processes.
Innovation Solution
A substrate treatment method involving a higher-speed rinsing step followed by a deceleration rinsing step, where the rotation speed is reduced and the rinse liquid supply flow rate is increased, ensuring the formation of a puddle-like rinse liquid film that covers the entire substrate surface, regardless of its state, through a combination of steep deceleration and gradual puddling steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is rotated at a low speed to form a puddle-like rinse liquid film, then the rinse liquid is retained on the front surface to form a liquid film, but the rinse liquid film is not necessarily formed on the entire front surface and parts of the substrate are liable to be exposed
Solution Approach 1:
The deceleration process is divided into multiple stages: a first deceleration stage with a first deceleration rate, and a second deceleration stage with a second deceleration rate. This segmentation allows the substrate to be decelerated in steps, ensuring complete coverage of the rinse liquid film while optimizing the overall deceleration time.
Solution Approach 2:
The deceleration rate is dynamically adjusted during the rinsing process. The control unit switches between different deceleration rates based on the process stage, enabling the system to adaptively control the formation of the puddle-like rinse liquid film across the entire substrate surface.
2Reliability
If the rotation speed is reduced to form a puddle-like liquid film, then the liquid film is retained on the substrate surface, but the process time is extended due to gradual deceleration
Solution Approach 1:
The deceleration process is segmented into two distinct stages with different deceleration rates. The first stage uses a slower deceleration rate to ensure proper liquid film formation, while the second stage uses a faster deceleration rate to reduce the overall time required, thus balancing reliability and time efficiency.
Solution Approach 2:
The deceleration rate parameter is changed during the process. By switching from a first deceleration rate to a second deceleration rate, the system optimizes both the quality of liquid film formation and the total process time, preventing excessive time loss while ensuring reliable puddle-like film formation.
3Reliability
If a single deceleration rate is used, then the process is simple, but the rinse liquid may not cover the entire substrate surface uniformly
Solution Approach 1:
The control mechanism dynamically adjusts the deceleration rate during the rinsing process. By implementing a control unit that can switch between different deceleration rates, the system achieves uniform rinse liquid coverage across the entire substrate surface while maintaining reasonable operational simplicity.
Solution Approach 2:
The deceleration process is segmented into stages with different rates, allowing the rinse liquid to spread uniformly across the substrate surface during the first stage, and then completing the coverage efficiently in the second stage, thus achieving uniform coverage without excessive complexity.
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 reliably forms and maintains a puddle-like rinse liquid film over the entire substrate surface, preventing exposure and optimizing the removal of chemical liquids and subsequent drying, even on hydrophobic or larger substrates, while reducing the time required for the deceleration process.
Implementation Method 1
the rotation speed of the substrate is zero or low when the IPA liquid is supplied. Since no centrifugal force or a smaller centrifugal force acts on the IPA liquid, the IPA liquid is retained on the front surface of the substrate to form a liquid film
Implementation Method 2
the rotation speed of the substrate is reduced from the liquid treatment rotation speed to a lower speed. At this time, a smaller centrifugal force acts on the rinse liquid supplied to the substrate. Therefore, the rinse liquid stagnates on the front surface of the substrate, so that the puddle-like rinse liquid film is retained on the entire front surface of the substrate
Data Source
AI summary
A substrate treatment method is provided, which includes a rinsing step of supplying a rinse liquid to a front surface of a rotating substrate after a chemical liquid step. The rinsing step includes a higher-speed rinsing step and a deceleration rinsing step to be performed after the higher-speed rinsing step. The deceleration rinsing step includes a liquid puddling step of reducing the rotation speed of the substrate within a rotation speed range lower than a rotation speed employed in the higher-speed rinsing step and supplying the rinse liquid to the front surface of the substrate at a flow rate higher than a maximum supply flow rate employed in the higher-speed rinsing step, whereby a puddle-like rinse liquid film is formed on the front surface of the substrate.