Polyphosphate Cleaning Solution for Semiconductor Wafer Particle Removal

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Solution Overview

Problem

Current methods for removing small particles from semiconductor wafers and hard disks face challenges in avoiding damage to fragile patterns and excessive underetching, as mechanical methods can damage patterns and chemical underetching removes valuable surface material, while traditional chemical methods are inefficient for very small particles.

Innovation Solution

A cleaning solution comprising polyphosphates, such as tripolyphosphates, is used in conjunction with optional acoustic energy to remove particles without mechanical forces or underetching, utilizing electrostatic repulsion and suspended particles like colloidal silica to effectively dislodge adhered particles from substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical methods (brush scrubbing, megasonic vibration, high pressure water jet, aerosol jet bombardment, polishing, ice blasting) are used to remove particles, then particle removal efficiency is improved, but fragile patterns on the substrate surface are damaged

Engineering Contradiction:

Improveparticle removal efficiencyVSAvoiddamage to fragile patterns

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical particle removal methods with a chemical solution containing polyphosphates that remove particles through electrostatic repulsion and chemical interaction, eliminating the need for mechanical forces that damage fragile patterns

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical parameters of the cleaning solution by using polyphosphates with specific electrostatic properties and adjusting pH levels to optimize particle removal while protecting substrate patterns from damage

Inventive Principle:

Principle #35Parameter changes

2Productivity

If chemical underetching is used to remove particles, then particle removal is achieved, but valuable surface material is removed

Engineering Contradiction:

Improveparticle removal capabilityVSAvoidsurface material loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent modifies the chemical composition parameters by using polyphosphates instead of traditional underetching chemicals, changing the removal mechanism from material dissolution to electrostatic repulsion and selective particle detachment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the chemical underetching mechanism with an electrostatic and chemical interaction mechanism that targets particles specifically without removing the substrate surface material

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If traditional chemical methods (RCA cleaning sequence with NH4OH, H2O2, H2O) are used, then cleaning is performed, but very small particles are not effectively removed

Engineering Contradiction:

Improvecleaning process effectivenessVSAvoidremoval of very small particles

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the chemical composition by introducing polyphosphates with specific electrostatic properties and pH levels that enhance the ability to remove submicron particles while maintaining compatibility with existing cleaning processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite cleaning solution that combines polyphosphates with traditional cleaning chemicals to achieve both broad-spectrum cleaning effectiveness and enhanced capability for removing very small particles

Inventive Principle:

Principle #40Composite materials

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

The method effectively removes small particles from substrates without damaging fragile structures or substantial underetching, improving particle removal efficiency and maintaining surface integrity, especially for submicron particles and patterned surfaces.

Implementation Method 1

utilizing electrostatic repulsion and suspended particles like colloidal silica to effectively dislodge adhered particles from substrates

Methodology Applied

Scientific EffectElectrostatic repulsion: Electrostatics

Implementation Method 2

applying acoustic energy to the cleaning solution while the cleaning solution is in contact with the surface

Methodology Applied

Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentUSRE46454E1Particle removal method using an aqueous polyphosphate solution

Publication Date: 2017.06.27 FONTANA TECH

AI summary

A method and cleaning solution for cleaning electronic substrates, such as a semiconductor wafers, hard disks, photomasks or imprint molds. The method comprises the steps of contacting a surface of the substrate with a cleaning solution comprised of a polyphosphate, and then removing the cleaning solution from the surface. Additional optional steps include applying acoustic energy to the cleaning solution while the cleaning solution is in contact with the surface, and removing the cleaning solution from the surface by rinsing the surface with a rinsing solution with or without the application of acoustic energy. The cleaning solution comprises a polyphosphate, such as any of the water soluble polyphosphates. Depending on the application, the cleaning solution may also comprise a base and/or a quantity of suspended particles. Complexing agents, amines, biocides, surfactants and/or other substances, may also be added to the cleaning solution.