Substrate Treatment Liquid Reuse With Standby Concentration Adjustment
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Solution Overview
Problem
The concentration of hydrogen peroxide in treatment liquids reused in semiconductor processes decreases over time due to decomposition by titanium, leading to reduced etching rates and increased costs from excessive hydrogen peroxide supplementation.
Innovation Solution
A substrate treating apparatus and method that involves storing treatment liquids with hydrogen peroxide in a main tank, recovering used liquids, and reusing them after concentration adjustment. This adjustment is done by discharging the treatment liquid in a heated state from a nozzle to evaporate part of the diluting solution, thereby increasing the hydrogen peroxide concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If treatment liquid is stored and reused in the main tank, then cost reduction is achieved through reuse, but hydrogen peroxide concentration decreases over time due to titanium decomposition
Solution Approach 1:
The system performs preliminary concentration adjustment during standby time by heating and evaporating the treatment liquid before it is needed for substrate treatment. This preliminary action ensures the treatment liquid is ready for immediate use at the correct concentration, eliminating the need for long-term storage and subsequent concentration correction.
Solution Approach 2:
The system changes the temperature parameter of the treatment liquid during standby time to accelerate evaporation and concentration adjustment. By heating the liquid to a higher temperature during standby periods, the system efficiently adjusts the hydrogen peroxide concentration to the required level before treatment begins.
2Reliability
If hydrogen peroxide is continuously supplemented to maintain concentration, then etching rate is maintained, but cost increases due to excessive supplementation
Solution Approach 1:
Instead of continuous supplementation, the system performs periodic concentration adjustment during standby time. The treatment liquid is heated and evaporated at specific intervals when the substrate is not being treated, maintaining the required hydrogen peroxide concentration without continuous addition of fresh peroxide.
Solution Approach 2:
The system uses the treatment liquid's own evaporation during standby time to concentrate the hydrogen peroxide solution. By heating the liquid and allowing partial evaporation of water, the system self-adjusts the concentration without requiring external supplementation, thereby maintaining etching rate while reducing peroxide consumption.
3Loss of substance
If treatment liquid is discharged and evaporated to adjust concentration, then hydrogen peroxide concentration is maintained, but energy is consumed for heating
Solution Approach 1:
The system performs heating and evaporation only during standby time when no substrate treatment is occurring. This periodic operation ensures that energy is consumed only when necessary for concentration adjustment, rather than continuously during active treatment processes.
Solution Approach 2:
The system continuously maintains the treatment liquid in a heated state during standby time to enable rapid concentration adjustment when needed. By keeping the liquid heated and ready during non-productive periods, the system ensures immediate availability of properly concentrated treatment liquid without energy-intensive corrections during active treatment.
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 method effectively maintains the hydrogen peroxide concentration within a set range, enhancing the etching rate and reducing the need for excessive hydrogen peroxide supplementation, thus optimizing the reuse of treatment liquids and lowering costs.
Implementation Method 1
discharging the treatment liquid in a heated state from the nozzle to evaporate a part of the diluting solution
Implementation Method 2
a heating member for heating the treatment liquid
Data Source
AI summary
Disclosed is a method of adjusting a concentration of a chemical liquid in a treatment liquid, the method including: treating a substrate by supplying a treatment liquid stored in a main tank from a nozzle in a heated state to the substrate, and recovering the treatment liquid used in the treatment of the substrate to the main tank directly or via still another tank, and then reusing the recovered treatment liquid, a concentration adjustment operation of adjusting a concentration of the treatment liquid in the main tank is performed in a standby time period in which the substrate is not treated with the treatment liquid, and the concentration adjustment operation is performed by discharging the treatment liquid in a heated state from the nozzle to evaporate a part of the diluting solution, and recovering the discharged treatment liquid to the main tank.