Sustainability Challenges Around SiC Polishing

Slurry recycling supports cleaner semiconductor manufacturing

Sustainability is a key pillar of Entegris’ Corporate Social Responsibility program. As the semiconductor industry advances toward higher performance and greater integration, so too must our commitment to responsible manufacturing. To this end, we’re innovating not just in performance but in environmental impact—especially in how we use water, manage waste, and design consumables like slurries for reuse.

One of our key efforts is slurry recycling for chemical mechanical planarization (CMP) on silicon carbide (SiC) wafers. Our SiC journey includes developing technologies and solutions that address sustainability up front. Let’s take a closer look at how we are enabling water reclamation, slurry recycling, smarter chemistry, and wastewater treatment through our innovative programs.

Meeting Water Goals

Semiconductor manufacturing, particularly the CMP process, is water-intensive. Entegris has set an ambitious target: reduce water usage intensity by more than 50% by 2030.

Part of this goal involves finding areas where we can reduce overall water consumption—this can be as simple as infrastructure improvements, such as finding and repairing leaks in our facilities. Another contributor to achieving our water goal is water reclamation—taking water used in our manufacturing process and treating it so that it can be safely released into the wastewater stream.

However, a larger opportunity lies in process innovation. In the case of SiC wafer polishing, this means we are taking more sustainable approaches to how we handle and recycle slurries used in this vital process.

Slurry Recycling

SiC polishing requires slurries that are both chemically aggressive and physically stable. Traditionally, the used slurry becomes hazardous waste, destined for costly treatment and disposal. Entegris is changing that paradigm.

To make it easy and beneficial for customers to cycle slurry waste back into production rather than discarding it, we have developed a SiC polishing slurry that lets them reintroduce up to 80% of used slurry into their process, supplemented with just 20% fresh slurry.

Designed to enable recycling and reuse, our slurry combines proprietary particles, stabilizers, and pH buffers, delivering excellent stability and removal rate with less than a 10% performance drop, even after nine recycling cycles. This is well within CMP process tolerances and does not lead to scratches or surface degradation.

The result? More than 75% reduction in hazardous slurry waste, and significant savings in both consumables and disposal costs.

Smarter Slurry Chemistry

Entegris’s slurry innovation doesn’t stop at recyclability. We’re also tackling sustainability at the source with dilutable, high-performance slurries. Concentrated formulations reduce the volume of slurry shipped, cutting carbon footprint by up to 3x. In addition, we have developed novel rate-boosting additives that reduce the amount of permanganate chemistry required for effective polishing, lowering permanganate waste generation by 2-3x as well.

These innovations mean not only cleaner manufacturing but also a lower cost per wafer for CMP processes without compromising throughput.

Wastewater Treatment

Of course, not all waste can be recycled. Entegris supports customers in designing integrated systems that separate non-hazardous water from more challenging components like permanganate and abrasives. Depending on the system, treated water—up to 90% of the original volume—can be reclaimed and reused.

Two main strategies being pursued are:

• Chemical treatment and filtration: Neutralizes permanganate byproducts and heavy metals with proven chemistry, then filters down to <5 ppm manganese levels.
• Evaporative separation: A new system in development that uses evaporation to recover 70–90% of slurry water, reducing the burden on chemical treatments and enabling efficient reuse.

While Entegris is not a licensed waste processor, we actively partner with fab teams to provide chemistry guidance, process support, and analytical services as they work with certified treatment vendors.

Our Commitment

By integrating slurry recycling and advanced wastewater management, Entegris is on track to reduce combined slurry waste and wastewater by as much as 95% for SiC CMP processes. This isn’t just a win for the environment—it’s a breakthrough in process efficiency and cost-effectiveness.

At Entegris, we believe every advancement in semiconductor manufacturing should come with a parallel advancement in environmental responsibility. Through customer collaboration and science-backed innovation, we’re delivering solutions that help fabs meet their performance and sustainability goals in parallel.

Want to learn more? Contact us.