Deionization Bath Control for Wafer Metal Ion Contamination

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Solution Overview

Problem

Conventional semiconductor fabrication techniques fail to adequately prevent particle contamination of wafers during processing, requiring expensive and inefficient manual adjustments to maintain flow rates and pressure within processing chambers.

Innovation Solution

An automated deionization bath tank system that samples and analyzes the tank solution for metal ion concentrations, performing remediation by adjusting the deionizing solution concentration and temperature to maintain threshold levels, thereby reducing metal ion contamination in situ.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If manual adjustments are made to maintain flow rate and pressure in processing chambers, then particle contamination is reduced, but overhead costs and hardware expenses increase significantly

Engineering Contradiction:

Improveparticle contaminationVSAvoidoverhead hardware

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The deionization bath tank system automatically monitors and adjusts the ionic content of the liquid medium without external intervention. The system self-regulates by detecting metal ion concentrations and automatically replenishing deionized water or adjusting flow rates, eliminating the need for manual adjustments and complex overhead hardware while maintaining clean processing conditions

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical adjustment systems with an automated electronic control system that uses sensors to detect ionic content and automatically adjusts the deionization process. This substitution of mechanical manual operations with automated sensing and control reduces hardware complexity while effectively preventing particle contamination

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If conventional deionization processes are used without in-situ monitoring, then metal ion contamination accumulates in the bath tank, but wafer reprocessing costs increase

Engineering Contradiction:

Improvemetal ion contaminationVSAvoidwafer reprocessing

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system continuously monitors the ionic content of the liquid medium in the deionization bath tank using sensors that detect metal ion concentrations. This feedback information is used by the control system to automatically adjust deionization parameters, replenish deionized water, or alert operators when the bath requires maintenance, preventing metal ion accumulation and eliminating the need for wafer reprocessing

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary deionization and monitoring actions before metal ion contamination reaches problematic levels. By continuously detecting ionic content and proactively adjusting deionization parameters or replenishing the bath, the system prevents contamination accumulation that would otherwise require wafer reprocessing, thereby maintaining continuous productivity

Inventive Principle:

Principle #10Preliminary action

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 reduces the need for wholesale reprocessing of wafers by addressing metal ion contamination directly within the deionization bath tank, enhancing the efficiency and effectiveness of the semiconductor fabrication process while minimizing overhead costs.

Implementation Method 1

immersing the wafer in a deionization tank, wherein the deionization tank comprises a tank solution that comprises a deionizing solution

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

the tank solution to determine a metal ion concentration within the tank solution... performing remediation within the deionization tank

Methodology Applied

Scientific EffectChemical complexation: Chemical Bonding

Data Source

PatentUS11742196B2Systems and methods for metallic deionization

Publication Date: 2023.08.29 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

In an embodiment, a method includes: receiving a wafer from a first dilution tank; immersing the wafer in a deionization tank, wherein the deionization tank comprises a tank solution that comprises a deionizing solution; determining a metal ion concentration within the tank solution; performing remediation within the deionization tank in response to determining that the metal ion concentration is greater than a threshold value; and moving the wafer to a second dilution tank.