Wafer Pre-Wetting and Rotation Control for Temperature Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The temperature of a substrate, such as a semiconductor wafer, becomes non-uniform during liquid processing due to the cooling effect at the peripheral edge, which affects the processing uniformity and efficiency.
Innovation Solution
A method involving heating the substrate, forming a liquid film on its surface using a pre-wetting liquid, and adjusting the substrate's temperature through controlled supply of heated and cooled deionized water to the back surface while rotating the substrate at varying speeds to maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate is heated and rotated at high speed to supply heated liquid to the center, then the temperature increase efficiency is improved, but the in-plane temperature uniformity deteriorates due to cooling at the peripheral edge
Solution Approach 1:
The patent applies different rotational speeds at different radial positions of the substrate. The center region rotates at a first rotational speed while the peripheral region rotates at a second rotational speed that is lower than the first. This local differentiation of rotational speed compensates for the cooling effect at the periphery, maintaining temperature uniformity across the substrate surface while still achieving efficient temperature increase.
2Quantity of substance
If the substrate rotational speed is increased to improve liquid film formation, then the liquid film coverage is improved, but the temperature uniformity deteriorates due to enhanced cooling at the peripheral edge
Solution Approach 1:
The patent implements local quality control by setting different rotational speeds for different regions of the substrate. The center region uses a higher rotational speed to ensure adequate liquid film formation, while the peripheral region uses a lower rotational speed to minimize cooling effects. This regional differentiation allows sufficient liquid film coverage while maintaining temperature uniformity across the entire substrate surface.
3Productivity
If heated chemical liquid is supplied to the substrate to improve processing temperature, then the processing efficiency is improved, but chemical liquid consumption increases due to continuous heating requirements
Solution Approach 1:
The patent applies preliminary heating to the substrate before the chemical liquid processing step. By increasing the substrate temperature in advance through controlled heating with rotational speed adjustment, the substrate reaches the required processing temperature before chemical liquid is supplied. This preliminary action reduces the need for continuous heated chemical liquid supply during processing, thereby decreasing chemical liquid consumption while maintaining processing efficiency.
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 enhances the in-plane temperature uniformity of the substrate, reduces chemical liquid consumption, and improves processing efficiency by stabilizing the substrate temperature during liquid processing.
Implementation Method 1
increasing a temperature of a substrate by heating the substrate
Implementation Method 2
decreasing the temperature of the substrate
Implementation Method 3
forming a liquid film of a pre-wetting liquid on a first surface of the substrate by supplying the pre-wetting liquid to the first surface of the substrate
Implementation Method 4
forming a liquid film of a pre-wetting liquid on a first surface of the substrate
Implementation Method 5
the substrate is easily cooled at the peripheral edge thereof having a relatively high peripheral speed
Data Source
AI summary
A substrate processing method includes: increasing a temperature of a substrate by heating the substrate; after the increasing the temperature of the substrate, forming a liquid film of a pre-wetting liquid on a first surface of the substrate by supplying the pre-wetting liquid to the first surface of the substrate while heating and rotating the substrate at a first rotational speed; after the forming the liquid film, processing the first surface of the substrate with a chemical liquid by supplying the chemical liquid to the first surface of the substrate while heating and rotating the substrate at a second rotational speed that is lower than the second rotational speed; and after the processing the first surface of the substrate, decreasing the temperature of the substrate.