What is the Plasma Cleaning Process in the Semiconductor Industry?

In semiconductor manufacturing, plasma cleaning uses ionized gases to eliminate residues before lithography and bonding, increasing yield and reliability.

How Plasma Cleaning Works in Semiconductors

The typical semiconductor plasma cleaning setup involves:

1. Argon Plasma Cleaning – Used to strip away organic residues from lead frames, wafers, and pads.

2. Surface Activation – Plasma excites the surface, increasing surface energy for optimal adhesion.

3. Process Control – The recipe (gas flow, power, pressure, duration) is tightly controlled to avoid damaging delicate parts.

   
   

In sensitive applications, direct plasma configurations are used. The electrode is positioned above the part to prevent direct RF contact—ideal for parts susceptible to damage.

Leaky chambers or poorly tuned recipes can lead to issues like oxidation. For example, if oxygen leaks in from outside, it can leave oxidation marks on wire bond pads.

Benefits of Plasma Cleaning in Semiconductor Processes

• Sub-micron Contaminant Removal

  • Removes carbon-based residues invisible to visual inspection

  • Prepares surfaces for consistent wire bonding and mould adhesion

    
    

• Oxide Layer Removal

  • Restores exposed bare metal

  • Especially effective with hydrogen plasma for oxide-sensitive surfaces

    
    

• No Wet Chemicals

  • Avoids ionic contamination and disposal risks

  • Clean, dry, and environmentally stable

    
    

• Protects Sensitive Substrates

  • Tunable process parameters prevent plasma damage

    
    

Direct plasma mode available for high-precision components

Applications in Semiconductor Manufacturing

• Wire Bonding Preparation

  • Ensures bond pads are free of oxides and organic contaminants

  • Prevents NSOP (Non-Stick-On-Pad) failures

    
    

• Die Attach and Underfill

  • Improves adhesion for epoxies and adhesives

  • Reduces voiding and delamination

    
    

• Lead Frame Cleaning

  • Enhances bondability and plating consistency

    
    

• Flip Chip Assembly

  • Ensures bump contact reliability by cleaning interconnects

    
    

• Wafer-Level Packaging (WLP)

  • Prepares die surfaces for redistribution layer (RDL) deposition

    
    

Types of Plasma Systems for Semiconductor Lines

Batch Plasma Systems

• Common in lead frame cleaning or high-mix, low-volume lines

• Controlled, uniform exposure

  
  

Inline Plasma Systems

• Integrated into bonding or assembly lines

• Enables high-throughput and traceability

  
  

Direct Plasma

• Minimises direct RF contact

  
  

Hydrogen Plasma

• Specially used for oxide removal

• Restores metal surfaces like copper or aluminium

Plasma cleaning is not just another prep step—it’s foundational to long-term device reliability. With the right system and tuning, it can protect sensitive parts, reduce rejects, and improve final yield.

If your plasma process is damaging your product, it may be time to review your setup. Chamber leaks and recipe errors are often the culprits.

Need to troubleshoot your process or evaluate a better fit for your production line? Talk to a plasma expert who can match the right tool to your application.

FAQs

Why is plasma cleaning preferred in wire bonding?

It removes invisible residues and oxides, allowing for better intermetallic bonds and reduced NSOP defects.

Can plasma damage my device?

Only if poorly configured. With the right parameters or direct plasma setup, damage can be avoided.

What gas is used in semiconductor plasma cleaning?

Argon is common for cleaning. Hydrogen is used for oxide removal. Oxygen can cause unwanted oxidation if not controlled.

Is plasma cleaning better than wet cleaning for semiconductors?

Yes. Plasma is residue-free, dry, and controllable—critical for microelectronics.

What issues can occur in a faulty plasma process?

Oxidation marks, incomplete cleaning, or substrate damage—typically from oxygen leaks or incorrect recipes.