Solution Supplying Unit for Uniform Mixing of Sulfuric Acid and Hydrogen Peroxide
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Solution Overview
Problem
The existing solution supplying units for semiconductor photolithography struggle to uniformly mix sulfuric acid and hydrogen peroxide due to their different specific gravities, leading to uneven mixing and pressure issues, resulting in inconsistent and uncontrollable flow of the photoresist removal solution.
Innovation Solution
A solution supplying unit with a tangentially connected first supplying tube for sulfuric acid and a second supplying tube for hydrogen peroxide, where the hydrogen peroxide is introduced through a central axis to minimize the effect of centrifugal force, combined with a rotating blocking part and exhaust mechanism to prevent bubble-induced pressure changes and ensure uniform mixing and controlled flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If sulfuric acid and hydrogen peroxide are mixed using turbulence in the solution supplying unit, then mixing is attempted, but uniform mixing is difficult due to different specific gravities
Solution Approach 1:
The mixing process is segmented into two distinct stages: first, sulfuric acid is introduced tangentially to create rotational flow; second, hydrogen peroxide is introduced through the central axis. This segmentation allows each component to be introduced in a controlled manner that exploits their density differences rather than fighting against them, achieving uniform mixing without complex mechanisms.
Solution Approach 2:
The first supplying tube is positioned asymmetrically at the tangential direction to induce rotation, while the second supplying tube is positioned symmetrically at the central axis. This asymmetric-symmetric combination creates a controlled rotational flow pattern that facilitates uniform mixing of the two solutions with different specific gravities.
2Stability of the object's composition
If hydrogen peroxide is provided into the solution supplying unit, then mixing occurs, but bubbles are generated due to boiling
Solution Approach 1:
The harmful bubbles generated during mixing are extracted and removed from the system through a dedicated bubble removal hole. This separates the mixing function from the bubble accumulation problem, allowing the chemical reaction to proceed while continuously eliminating the harmful byproduct that causes pressure instability.
Solution Approach 2:
The exothermic reaction between sulfuric acid and hydrogen peroxide, which generates bubbles and heat, is harnessed to create vigorous mixing action. The bubbles and thermal energy that would normally be considered harmful are converted into beneficial mixing forces that enhance the homogeneity of the solution.
3Quantity of substance
If bubbles are generated in mixing, then pressure inside the solution supplying unit increases, but solution flow becomes inconsistent and uncontrollable
Solution Approach 1:
The bubble removal hole provides continuous feedback by allowing bubbles to escape and pressure to equalize. This creates a self-regulating system where pressure build-up is automatically prevented, maintaining consistent solution flow without requiring external pressure control mechanisms.
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 solution supplying unit effectively mixes sulfuric acid and hydrogen peroxide uniformly, preventing bubble-induced pressure changes and ensuring a consistent, controlled flow of the mixed solution, thereby improving the accuracy and reliability of photoresist removal processes.
Implementation Method 1
The sulfuric acid and the hydrogen peroxide are rotated in the solution supplying unit to use turbulence in mixing the sulfuric acid and the hydrogen peroxide
Implementation Method 2
The sulfuric acid and the hydrogen peroxide are rotated in the solution supplying unit to use turbulence in mixing the sulfuric acid and the hydrogen peroxide
Implementation Method 3
the bubbles are flowed out with the solution. Thus, the amount of the out-flowed solution is hard to be accurately controlled
Data Source
AI summary
A solution supplying unit includes a body, a first supplying tube and a second supplying tube. The body includes a chamber having a substantially circular cross-section to receive a solution and an out-flowing part connected to the chamber to flow out the solution. The first supplying tube is disposed at a side of the body, tangentially connected to the chamber, and supplying a first solution into the chamber to rotate the first solution in the chamber. The second supplying tube has an end portion, and supplying a second solution into the chamber to mix the first solution with the second solution. The end portion is formed through the body and is adjacent to a central axis of the body.