Technology Principle

Microbubble cleaning leverages the physical and interfacial behavior of micron-scale gas bubbles in liquid systems to enhance contamination removal.

When microbubbles interact with solid surfaces:

• Bubble surface charge interacts with particles

• Interfacial tension changes at the surface

• Microbubble collapse induces localized micro-flow

• Adsorbed contaminants are detached

Compared to conventional chemical cleaning, microbubble systems:

• Reduce chemical dependency

• Lower surface damage risk

• Improve removal of sub-micron particles

• Support environmentally optimized processes

Core Mechanisms

1. Electrostatic Interaction

Charged microbubbles attract oppositely charged particles, enhancing detachment efficiency.

2. Interfacial Tension Reduction

Gas-liquid interfaces weaken adhesion forces between particles and substrate surfaces.

3. Microstreaming & Local Flow Disturbance

Bubble collapse generates localized micro-currents improving boundary layer disruption.

4. Enhanced Mass Transfer

Improves oxidant or reactive species contact efficiency (if combined with O₂ or chemistry).

System Architecture

A typical microbubble cleaning module includes:

• Gas control unit (O₂ / N₂ / CO₂ optional)

• Microbubble generator (venturi / porous diffuser / cavitation-based)

• Temperature control (optional 40–80°C)

• Flow stabilization chamber

• Recirculation or single-pass configuration

• Waste or reclaim management

System design options:

• Inline module integration

• Standalone tank system

• FOUP internal cleaning integration

• Chemical loop enhancement

Semiconductor Applications

▸ Wafer Surface Pre-Clean

Removes particles before wet process or deposition.

▸ Chemical Line Cleaning

Enhances contamination removal inside PFA / PVDF tubing systems.

▸ FOUP & Carrier Cleaning

Reduces organic & particle contamination inside storage carriers.

▸ Filter Regeneration Assistance

Assists in removal of loosely bound contaminants.

▸ IPA / Acid Process Optimization

Enhances cleaning efficiency while reducing chemical usage.

Performance Metrics

Typical evaluation parameters include:

• Particle removal efficiency (%)

• LPC particle count reduction

• TOF-MS background reduction

• Contact angle variation

• Surface integrity (SEM)

• ORP / DO monitoring (if oxidant involved)

Advantages

✓ Lower chemical consumption
✓ Reduced surface damage risk
✓ Environmentally optimized process
✓ Scalable to large systems
✓ Compatible with existing wet benches

Optional Advanced Modes

• O₂ Microbubble Oxidation Mode

• CO₂-assisted Cleaning

• Hybrid Microbubble + Chemical Mode

• Heated Microbubble System (60–80°C)

• Fast-loop Inline Enhancement

Qualification Flow

1. Process requirement definition

2. Bubble size distribution confirmation

3. Pilot test (bench scale)

4. Particle & chemical analysis

5. Surface integrity evaluation

6. Scale-up implementation