Chemical Liquid Exchange Using Multi-Tank Si Concentration Control
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Solution Overview
Problem
The existing chemical liquid exchange processes in semiconductor etching are inefficient, leading to prolonged facility stoppages and increased risk of process defects due to improper Si concentration in the chemical liquid.
Innovation Solution
A method and system for chemical liquid exchange that allows partial reuse of chemical liquid during the exchange process, maintaining Si concentration control through measurement and adjustment, and utilizing a recycling unit to efficiently recover and heat the chemical liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all reused chemical liquid is drained and then new chemical liquid is filled, then the chemical liquid is completely replaced, but the facility stoppage time is prolonged and productivity is reduced
Solution Approach 1:
The patent divides the chemical liquid storage system into multiple tanks (first recycling tank, second recycling tank, first sub-tank, second sub-tank, and main tank). This segmentation allows partial reuse of chemical liquid from one tank while draining and replacing liquid in another tank, enabling continuous operation without complete facility stoppage.
Solution Approach 2:
The patent prepares new chemical liquid in advance in sub-tanks before it is needed in the main tank. This preliminary action ensures that when chemical liquid exchange is needed, the replacement liquid is already ready, minimizing the stoppage time required for the exchange process.
2Productivity
If chemical liquid is reused extensively, then productivity is improved by avoiding stoppages, but Si concentration control becomes difficult leading to process defects
Solution Approach 1:
The patent incorporates an Si measurer that continuously monitors the Si concentration in the chemical liquid supplied to the chamber. This feedback mechanism allows the system to detect changes in Si concentration and trigger appropriate actions, such as draining the chemical liquid when concentration exceeds predetermined thresholds, thereby maintaining manufacturing precision.
Solution Approach 2:
The patent changes the operational parameters of chemical liquid reuse by implementing a multi-tank system with different functions. Some tanks are designated for reuse while others are for draining and replacement. This parameter change allows the system to balance productivity with quality control by managing Si concentration through controlled circulation and replacement.
3Loss of time
If chemical liquid is recovered and heated intensively, then the time to raise temperature is shortened, but energy consumption increases
Solution Approach 1:
The patent segments the chemical liquid recovery and heating process by dedicating one recycling tank specifically for intensive heating operations. This segmentation allows the system to concentrate heating resources on one tank at a time, reducing the overall time to raise temperature while managing energy consumption through focused rather than simultaneous heating of all tanks.
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 minimizes equipment stoppages, maintains process homeostasis by controlling Si concentration, and reduces the time required to prepare and supply the chemical liquid, thereby enhancing productivity and reducing defects.
Implementation Method 1
by heating the recovered chemical liquid in a recycling unit
Data Source
AI summary
A chemical liquid exchange method includes: recovering, by a first recycling tank, a first portion of a first chemical liquid that was previously used in a chamber; recovering, by a second recycling tank, a second portion of the first chemical liquid that was previously used in the chamber; supplying, from the first recycling tank, the first portion of the first chemical liquid to a first sub-tank; draining, from the second recycling tank, the second portion of the first chemical liquid; supplying, from the first sub-tank, the first portion of the first chemical liquid to a main tank; and receiving, by a second sub-tank, a second chemical liquid from an outside; and supplying, from the second sub-tank, the second chemical liquid to the main tank.