Semiconductor Water Recycle/Reclaim

Fab shops require large volumes of ultrapure water (UPW) and use chemicals during the fabrication of semiconductor devices, generating large volumes of wastewater, which must be reclaimed. Specially designed reclaim systems help reducing the effluent waste discharge, as well as minimizing the raw water needed for the production of UPW while protecting the environment. Ovivo technology is instrumental for providing reuse & reclaims water treatment systems essential to semiconductor fabrication

Semiconductor Water Recycle/Reclaim

The fabrication of semiconductor devices requires large volumes of ultrapure water and generates large volumes of wastewater. A reliable wastewater treatment and reclaim system is necessary to protect the environment and to safeguard the resources needed for the growth of the industry.

The low TOC rinse waters (second and final rinses, and organic‐free rinses) account for approximately 40% of the total UPW consumption in an average semiconductor fabrication facility. Depending on their conductivity, systems with or without ion‐exchange stages are used.

Rinse water containing organics is generated from several cleaning processes and organic baths. This high TOC rinse water can be recovered for recycle or reuse by Ovivo’s organic removal systems. These specialized plants consist of advanced monitoring and control devices, followed by activated carbon filters and various organic removal steps. The entire process is specifically designed to the type and concentration of the various organic compounds.

 

To which extend (%) used UPW can be reclaimed nowadays?

The reclaim rate is depending on the water quality to be reclaimed. Nowadays a reclaim rate between 50 and 70% should be possible if the consumed UPW streams are well segregated.

Is wastewater segregation a must to reclaim water?

All is matter of costs and benefit. As much segregation is done as more reclaiming at lowest costs for the user is possible.

What are the typical reclaim treatment processes available?

The process designs are depending on the segregated streams available. The typical contamination coming from semiconductor fabs are first and second rinse streams with contaminants containing free mineral acids (HF, HCl, H2SO4, HNO3, H3PO4), Ammonia, hydrogen peroxide, ozone, organics (mostly IPA). For these contaminants classical processes like: Activated carbon, catalysts (H2O2), ion exchange, reverse osmosis, adsorption, desorption, biofilter are mostly used and available.

Is “zero water discharge” a reasonable future concept for UPW systems?

Technically possible but not really reasonable because of too high capital and operating costs ,high energetic consumption, and high risks for the user.

Is TOC (mainly IPA) a problematic issue for reclaiming water to UPW production line?

Yes, IPA is a low molecular weight (60g/mol) polar molecule, which is very well water soluble and difficult to be removed in high extent. It is also easily oxidizable up to its next oxidation state, acetone which is then much less oxidizable to further states (acids),to be removed always in regards of the low TOC levels to be achieved in the UPW (< 1 ppb TOC). If the IPA concentrations in the streams to be reclaimed go up to several ppm TOC Ovivo developed a specific removal process to remove IPA as well as acetone very efficiently, through the so called TOCSORB process.

Numerous references, combined with our impressive list of installed facilities guarantees excellence and reliability supported by experienced employees.

Ovivo’s solutions for the reclaim of semiconductor wastewater, means:

  • More than 40 active wastewater treatment systems worldwide
  • Worldwide 5’000 m per hour of Semiconductor wastewater reclaimed
  • Long-term, repeated customers in Asia, Europe and the US

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