Wet Etch Tank Control Using Real-Time Chemical Feedback
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Solution Overview
Problem
Conventional wet processing systems in semiconductor manufacturing are manually controlled, leading to increased defects and decreased efficiency due to the lack of precise control over chemical composition, temperature, and flow rate changes during processes like etching, which affect the etch rate and quality of semiconductor substrates.
Innovation Solution
A wet processing system with a controller that continuously monitors real-time parameters such as pH, temperature, and electrical conductivity, and adjusts the composition, flow rate, and temperature of the liquid chemical to maintain optimal etch rates by automatically replenishing or replacing the chemical, ensuring consistent processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual control methods are used to determine dosing and etch rates, then operational simplicity is maintained, but manufacturing precision and reliability deteriorate due to increased defects and quality issues
Solution Approach 1:
The system implements real-time feedback control by continuously monitoring etch rate through optical measurements and using this information to automatically adjust chemical dosing. The controller receives optical signals indicating etch rate and modifies dosing parameters accordingly, replacing manual control with closed-loop automatic control that maintains precision while simplifying operation.
Solution Approach 2:
The patent replaces manual mechanical control operations with an automated optical-electronic control system. Optical sensors measure etch rate in real-time, and an electronic controller automatically adjusts dosing based on these measurements, substituting human-operated mechanical systems with automated sensor-actuator systems that provide continuous precision control.
2Device complexity
If manual calculations and test substrate measurements are used for dosing control, then system complexity is reduced, but productivity decreases due to decreased efficiency in high-volume manufacturing
Solution Approach 1:
The system enables continuous automatic adjustment of chemical dosing based on real-time etch rate measurements, eliminating the discontinuous nature of manual control where dosing is adjusted only after test substrate measurements. This continuous control maintains optimal etch rates throughout high-volume production, significantly improving manufacturing efficiency.
Solution Approach 2:
The control system performs self-adjustment by automatically modifying dosing parameters based on real-time optical measurements of etch rate. The system serves itself by using its own measurements to control its own operation, eliminating the need for external manual intervention and enabling high-speed automated production.
3Ease of operation
If chemical composition changes are not precisely controlled during etching, then process simplicity is maintained, but etch rate consistency deteriorates over time
Solution Approach 1:
The system uses real-time optical feedback to monitor etch rate and automatically adjusts chemical dosing to compensate for composition changes. The controller continuously modifies dosing parameters based on measured etch rate variations, maintaining stable chemical composition effects throughout the etching process without complex manual intervention.
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 solution enables precise control over wet processing systems, reducing defects and improving efficiency by maintaining consistent etch rates and quality of semiconductor substrates, even in high-volume manufacturing environments.
Implementation Method 1
The liquid chemical may be configured to etch the one or more substrates
Implementation Method 2
continuously receive real-time signals indicative of one or more of a pH, temperature, and electrical conductivity of the liquid chemical
Implementation Method 3
continuously receive real-time signals indicative of one or more of a pH, temperature, and electrical conductivity of the liquid chemical
Implementation Method 4
dosing unit configured to receive the liquid chemical from the wet processing tank and discharge a modified supply of the received liquid chemical into the wet processing tank
Implementation Method 5
adjust one or more of the composition, the flow rate, and the temperature of the modified supply of the liquid chemical discharged into the wet processing tank
Data Source
AI summary
A system and a method of wet processing includes receiving real-time signals indicative of one or more of a pH, a temperature, and an electrical conductivity of a liquid chemical in a wet processing tank, and determining values of one or more of a composition, a flow rate, and the temperature of the liquid chemical that will improve or maintain an etch rate of the liquid chemical in the wet processing tank. One or more of the composition, the flow rate, and the temperature of the liquid chemical in the wet processing tank may then be adjusted to the determined values.