Hydrogen peroxide (H₂O₂) is widely used across various industries for its oxidizing and disinfecting properties. In the microelectronics industry, it plays a critical role in both cleaning, processing, and etching processes.  

• Cleaning processes incorporate H₂O₂ with other chemicals to thoroughly remove contaminants from substrates and surfaces.  
• Wet etching processes use H₂O₂ and acids or bases to precisely remove (a) photoresist and organic materials from a semiconductor wafer to create the desired circuit patterns or (b) copper (metals) from the surface of the printed circuit board (PCB) to create conductive pathways for electronic components.
• Processing steps include chemical mechanical planarization and rinse baths for manufacturing processes.

For cleaning purposes, H₂O₂ is often combined with sulfuric acid (H2SO4) to form piranha acid or ammonia (NH3) to form base piranha, aggressive cleaning solutions used to efficiently strip organic residues from wafers. Once the piranha solution has served its purpose, a dangerous  waste product remains that needs to be handled properly to avoid environmental or personal damage. H₂O₂ concentrations can be 1% – 6% or higher in these solutions along with concentrated H2SO4, HCl, or NH3.  

For wet etch processes, H₂O₂ is typically combined with aggressive chemistries (such as nitric acid (HNO3)) or with etching chemistries (such as cupric chloride (CuCl)).  The peroxide acts as an oxidizing agent, helping to rapidly dissolve the exposed copper on the board by facilitating the chemical reaction with the primary etching agent (usually an acid like hydrochloric acid), leading to a faster and more efficient etching process; essentially, it “activates” the etching process by readily supplying oxygen atoms to the copper surface.

For processing steps, H₂O₂ may be included to aid in processing or may be rinsed from a cleaning or wet etch process.  For chemical-mechanical planarization (CMP), it helps to oxidize the surface of the material being polished, making it easier to remove and achieve a smooth, planar surface.  Essentially, it facilitates the material removal process by creating a more readily removable oxide layer on the substrate.

Regardless of the purpose, H₂O₂ must be abated to protect downstream processes like reuse, recycling, or treatment for discharge compliance. 

In this blog, we’ll explore how ElectraMet’s innovative Gamma system works to break down hydrogen peroxide and why it is an ideal solution for industries aiming to manage their peroxide treatment processes more effectively.

The Problem with Hydrogen Peroxide in Wastewater

Hydrogen peroxide, while highly effective for industrial cleaning, poses significant risks when it enters waste distribution streams. In high concentrations, it can damage equipment, disrupt downstream processes, and pose serious environmental hazards if released into water systems. This is particularly relevant in the semiconductor industry, where high concentrations of hydrogen peroxide are used to facilitate efficient manufacturing.  Highly concentrated solutions containing sulfuric acid, hydrochloric acid, and ammonia are for wafer etching and cleaning.. Treating and disposing of hydrogen peroxide safely is critical for ensuring compliance with environmental regulations and minimizing operational risks.

While traditional treatments have been used, they become less viable as H₂O₂ increases.  

• Activated Carbon efficacy lost > 0.05% H₂O₂
• Catalase loses efficacy > 0.5% H₂O₂ with pH-dependent reaction kinetics 
• Chemistry addition can be effective up to 5% H₂O₂ but present significant risks

If effective at elevated H₂O₂ concentrations, traditional treatment methods listed above are costly, inefficient, and require constant monitoring. Where other systems fail, ElectraMet’s Gamma system presents a more efficient and sustainable solution.

How ElectraMet’s Gamma System Works

ElectraMet’s Gamma system utilizes advanced electrochemical technology to efficiently break down hydrogen peroxide into harmless water (H₂O) and oxygen (O₂). The system incorporates specialized catalase cartridges that ensure consistent results.  Documented success has been achieved with piranha acid and base piranha to < 50 ppb H₂O₂. The Gamma system is automated, uses no chemistry, and does not produce sediment or organic foulants like traditional solutions.  

The Gamma system operates independently, continuously removing the hydrogen peroxide in wastewater streams. This reduces the need for labor-intensive management and minimizes the risk of human error, making it an ideal solution for industries that rely heavily on hydrogen peroxide for cleaning and etching processes.  Monitoring assures effluent specification is achieved. 

Advantages of ElectraMet’s Gamma System

No Chemical Dosing Required: The Gamma system eliminates the need for frequent dosing of catalase or other chemicals to treat hydrogen peroxide. This reduces labor and operational complexity, allowing facilities to focus on core operations.

Automated and Low-Maintenance: The Gamma system runs with minimal intervention, requiring no continuous monitoring. This automation enhances efficiency and frees up valuable resources for other critical tasks.

No Detrimental Byproducts: Activated carbon is known to fail at higher H₂O₂ concentrations and produce sediment carbon foulants. Catalase presents organic foulant issues along with unused catalase as a contaminant. ElectraMet’s Gamma system produces only H2O and O2 in the effluent. 

Environmentally Friendly: The Gamma system breaks hydrogen peroxide down into water and oxygen, leaving no harmful by-products. This reduces environmental risks and helps industries meet regulatory standards for wastewater disposal.

Cost-Effective: By reducing the need for manual intervention and chemical dosing, the Gamma system lowers long-term operational costs, offering a sustainable and financially sound approach to hydrogen peroxide treatment.

Application in the Semiconductor Industry

In semiconductor manufacturing where piranha acid use is common, the Gamma system provides a practical solution for treating hydrogen peroxide solutions. The Gamma system simplifies this process by automatically breaking down the hydrogen peroxide into harmless by-products, eliminating the need for complex chemical treatments and reducing the environmental impact.  The Gamma technology has opened the door for sulfuric acid recovery and chemical-free piranha solution abatement, reducing carbon footprint and turning costs into revenue generating functions. 

Beyond semiconductor cleaning, the Gamma system is suitable for any industry that relies on hydrogen peroxide in its processes, such as surface treatment or metal etching. Its versatility makes it an invaluable tool for improving the efficiency of wastewater treatment across a range of sectors.

Conclusion

As industries continue to seek more sustainable and efficient methods for managing hazardous waste, ElectraMet’s Gamma system offers an innovative solution for treating hydrogen peroxide. By automating the breakdown of hydrogen peroxide into water and oxygen, the Gamma system provides a reliable, eco-friendly, and cost-effective approach to wastewater management.

For industries like semiconductor manufacturing, where hydrogen peroxide is integral to the cleaning process, the Gamma system not only ensures compliance with environmental regulations but also reduces operational complexity and costs. By integrating the Gamma system into their wastewater treatment operations, companies can enhance safety, reduce environmental impact, and improve overall efficiency.