UV Absorbance Evaluation of Sonicated Cleaning Solutions

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Solution Overview

Problem

There is no objective method to evaluate the effectiveness of sonicated cleaning solutions used in cleaning processes, particularly for integrated circuit substrates, which can lead to surface damage and contamination, affecting device performance and yield.

Innovation Solution

A process involving the measurement of UV absorption spectra of sonicated solutions, comparison with reference spectra, and scaling to determine activation, allowing for adjustment of sonic energy to achieve optimal cleaning solution activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If concentrated cleaning solutions (SC-1) are used for cleaning IC substrates, then cleaning effectiveness is improved, but substrate surface damage and device performance degradation occur

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsubstrate surface damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the concentration parameter of the cleaning solution from high (concentrated SC-1) to low (superdilute or near zero dilution), and introduces sonication as a new parameter to enhance cleaning effectiveness at low concentrations, thereby resolving the contradiction between cleaning effectiveness and substrate damage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies mechanical vibration (sonication) to the cleaning solution to enhance its cleaning capability at superdilute concentrations, allowing effective cleaning without the harmful effects of concentrated solutions

Inventive Principle:

Principle #18Mechanical vibration

2Reliability

If concentrated cleaning solutions are used, then cleaning power is improved, but environmental harm and treatment costs increase

Engineering Contradiction:

Improvecleaning powerVSAvoidenvironmental contamination

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the concentration parameter from high to superlow, fundamentally altering the environmental impact profile while maintaining cleaning effectiveness through sonication

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces UV absorbance measurement as a feedback mechanism to monitor and optimize the sonicated solution's cleaning effectiveness, ensuring that superdilute solutions achieve the required cleaning power without environmental harm

Inventive Principle:

Principle #23Feedback

3Reliability

If concentrated cleaning solutions are used, then cleaning capability is improved, but metal contaminant deposition and device performance degradation occur

Engineering Contradiction:

Improvecleaning capabilityVSAvoidmetal contaminant deposition

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the concentration parameter to superdilute levels, eliminating the source of metal contaminant deposition while using sonication to maintain cleaning capability

Inventive Principle:

Principle #35Parameter changes

4Productivity

If there is no objective evaluation method for sonicated solutions, then process optimization is difficult, but implementing UV absorbance measurement adds process complexity

Engineering Contradiction:

Improveprocess optimization efficiencyVSAvoidevaluation process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces subjective or indirect evaluation methods with UV absorbance measurement, an optical method that provides objective, quantitative data for optimizing sonicated cleaning solutions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables the evaluation and optimization of sonicated cleaning solutions to ensure effective contaminant removal without substrate damage, enhancing the yield and performance of integrated circuit substrates.

Implementation Method 1

The sonicated solution is produced by applying acoustic energy (e.g., megasonic energy) to a solution containing a solute

Methodology Applied

Scientific EffectAcoustic cavitation: Acoustic Cavitation

Implementation Method 2

measuring UV absorption of the sonicated solution to produce a sample UV absorbance spectra

Methodology Applied

Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentUS8669532B2Evaluating a cleaning solution using UV absorbance

Publication Date: 2014.03.11 NANO GREEN TECH

AI summary

A process for evaluating a cleaning solution is described. The process includes: (a) subjecting a solution, including a solute and a solvent, to sonic energy to create a sonicated solution; (b) measuring UV absorption of the sonicated solution to produce a sample UV absorbance spectra; (c) obtaining a reference UV absorbance spectra; (d) scaling the reference UV absorbance spectra to the sample UV absorbance spectra at a lower range of the UV spectrum; (e) subtracting from the reference UV absorbance spectra the sample UV absorbance spectra to produce a differential UV spectra; and (f) evaluating at or near a peak of the sample UV absorbance spectra the differential UV absorbance spectra to determine whether the sonicated solution is activated.