Wafer Wet Cleaning Feedback Control via Drain Chemistry Analysis
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Solution Overview
Problem
Existing wafer cleaning processes in semiconductor manufacturing are inefficient in real-time monitoring and adjusting to contamination levels, leading to increased particle counts and prolonged processing times due to post-cleaning contamination analysis.
Innovation Solution
A real-time monitoring system that collects and analyzes the consumed wet etch chemistry during wafer cleaning to adjust cleaning parameters based on metal ion concentration in the chemical solution, allowing for dynamic process optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If real-time monitoring of contamination levels is implemented during cleaning, then productivity is improved, but device complexity increases
Solution Approach 1:
The system implements real-time feedback by continuously monitoring the concentration of metal ions in the cleaning solution using an analyzer. The controller receives signals from the analyzer and adjusts cleaning parameters dynamically based on the measured contamination levels, enabling closed-loop control that improves productivity while managing system complexity through automated feedback mechanisms.
Solution Approach 2:
The patent replaces manual or post-process contamination assessment with an automated analytical system that uses chemical analysis (measuring metal ion concentration in solution) to monitor contamination levels in real-time. This substitution of mechanical/physical inspection with chemical analysis enables continuous monitoring without significantly increasing mechanical system complexity.
2Loss of time
If cleaning parameters are adjusted based on real-time contamination assessment, then loss of time is reduced, but measurement precision requirements increase
Solution Approach 1:
The system uses the cleaning solution as an intermediary medium to indirectly measure wafer contamination. Instead of directly measuring contamination on the wafer surface, the system measures the concentration of metal ions in the cleaning solution, which correlates with the contamination level on the wafer. This intermediary approach enables real-time measurement with adequate precision for process control.
Solution Approach 2:
The system monitors changes in chemical parameters (metal ion concentration in cleaning solution) rather than physical parameters of the wafer itself. By measuring the chemical composition of the cleaning solution before and during the cleaning process, the system can assess contamination levels with sufficient precision to guide real-time parameter adjustments without requiring ultra-precise direct wafer surface measurement.
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
Reduces cleaning time for low-contamination wafers and ensures effective contamination removal by dynamically adjusting cleaning processes, thereby improving throughput and yield.
Implementation Method 1
analyzer configured to analyze the chemical solution collected in the drain collector to determine a concentration of metal ions in the chemical solution
Data Source
AI summary
The present disclosure describes a wafer cleaning process in which a drained cleaning solution, which is used to remove metal contaminants from the wafer, is sampled and analyzed to determine the concentration of metal ions in the solution. The wafer cleaning process includes dispensing, in a wafer cleaning station, a chemical solution on one or more wafers; collecting the dispensed chemical solution; determining a concentration of contaminants in the chemical solution; in response to the concentration of the contaminants being greater than a baseline value, adjusting one or more parameters in the cleaning process; and in response to the concentration of the contaminants being equal to or less than the baseline value, transferring the one or more wafers out of the wafer cleaning station.