Etching Liquid Flow Control for Uniform Substrate Processing
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Solution Overview
Problem
Existing substrate processing apparatuses suffer from processing unevenness due to air bubbles gathering around the upper portion of the processing tank, leading to a decrease in etching rate and temperature, which results in uneven etching on the substrate surface.
Innovation Solution
A substrate processing apparatus with controlled etching liquid supply and air bubble management, including discharge holes and a controller to adjust the etching liquid discharge amount and air bubble supply, ensuring more etching liquid reaches the upper substrate portion, thereby maintaining uniform etching across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air bubbles are supplied from below the substrate to ensure sufficient air bubble coverage, then the region with insufficient air bubbles is reduced, but air bubbles gather around the upper portion of the processing tank causing temperature decrease and processing unevenness
Solution Approach 1:
The patent applies local quality by providing multiple air bubble supply units at different locations (first air bubble supply unit at the bottom and second air bubble supply unit at the side wall) with different discharge characteristics. This creates localized air bubble distribution to address the temperature decrease in specific regions (upper portion) caused by air bubble gathering, while maintaining sufficient air bubble coverage in other regions.
Solution Approach 2:
The air bubble supply system is segmented into multiple independent air bubble supply units with different discharge orientations. The first air bubble supply unit discharges air bubbles upward from the bottom, while the second air bubble supply unit discharges air bubbles horizontally from the side wall. This segmentation allows independent control of air bubble distribution in different zones to prevent harmful gathering in the upper portion.
2Productivity
If conventional etching liquid supply methods are used to increase etching rate in the upper portion, then processing speed may improve, but processing unevenness cannot be reduced due to air bubble gathering and temperature decrease
Solution Approach 1:
The etching liquid supply system uses multiple etching liquid supply units with different discharge orientations tailored to specific regions. The first etching liquid supply unit discharges etching liquid upward toward the upper portion of the substrate, while the second etching liquid supply unit discharges etching liquid horizontally. This allows optimized etching liquid supply to each region based on its specific needs, maintaining high etching rates while ensuring uniformity.
Solution Approach 2:
The controller coordinates the operation of air bubble supply units and etching liquid supply units based on the processing state. By monitoring and adjusting the operation of different supply units, the system maintains optimal etching conditions throughout the substrate, preventing temperature decrease and processing unevenness while maintaining high productivity.
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 apparatus enhances etching uniformity by intensively supplying etching liquid to the upper substrate portion, increasing the etching rate and reducing processing unevenness.
Implementation Method 1
air bubbles supplied from an air bubble supply unit gather around an upper portion of a processing tank, resulting in a decrease in temperature of an etching liquid around the upper portion of the processing tank
Data Source
AI summary
A substrate processing apparatus includes: a processing tank storing an etching liquid; a substrate holder configured to immerse a substrate in the etching liquid; an etching liquid supply unit configured to supply the etching liquid into the processing tank, and including a first discharge hole in which a direction in which the etching liquid is discharged is directed to an upper portion of the substrate, and a second discharge hole disposed below the first discharge hole; an air bubble supply unit configured to supply air bubbles to the etching liquid from below the substrate; and a controller, wherein the controller controls the etching liquid supply unit to adjust a discharge amount of the etching liquid from the first discharge hole to be larger than a discharge amount of the etching liquid from the second discharge hole in a whole or part of a period of etching the substrate.