Semiconductor

The fabrication of semiconductor devices requires large volumes of ultrapure water (UPW) and generates vast quantities of wastewater. Only the purest possible water is acceptable for use in semiconductor manufacture. 

Ovivo’s technologies remove impurities from water at the limits of their detection with an ultimate reliability.

Ovivo provides complete solutions for single source source water management including:

• Ultrapure Water Treatment Plant
• Pre-treatment section
• Make-up section
• Polishing  section
• Distribution loops
• Reuse, Reclaim and Recycle of Waste Water
• Treatment of Waste Water

Ovivo integrates each process step, from project identification through construction to commissioning. We offer total solutions that encompass operator training, client services, system operation and maintenance, which can be governed by client-specific service contracts according to individual needs.

Beginning with an analysis of a client’s specific manufacturing condition, Ovivo designs and supplies customized water treatment solutions to meet the exceptionally high standards of the semiconductor industry. We can supply complete ultrapure water systems, waste water recycling and reuse systems as well as wastewater treatment plants. Ovivo’s global specialization enables us to implement systems that meet local regulatory environmental requirements as minimum standards.

The ultrapure water needed for semiconductor manufacture is the purest water feasible. It is produced by combining conventional, membrane, ion exchange, thermal and oxidising treatment processes. Ovivo designs and builds ultrapure water treatment plants that meet the following criteria:

• Ultrapure water (UPW) according to the latest ITRS road map specifications with total organic content (TOC) of <0.5 ppb and Boron < 20 ppt.
• Lowest cost of ownership
• A robust system for removal of the most difficult organics in raw water (urea)

The pre-treatment section of an ultrapure water plant uses filtration, ion exchange and membrane processes to produce permeate of lowest TOC and salt content. Ovivo’s experience shows that multimedia filtration with micro-flocculation followed by an activated carbon filter unit is one of the most effective pre-treatment combinations to remove traces of suspended matter and produces the optimum feed water for reverse osmosis. Ion exchange further removes salt and reduces fouling in the reverse osmosis units to the lowest possible levels. Raw water ultra-filtration is an alternative with even better outlet qualities. To a certain extent, activated carbon filters reduce TOC levels of reclaimed last rinses, too.

• Ovivo’s unique RO design for improved permeate quality

In the following make-up section, the main focus is on gas removal such as oxygen and CO2 as well as some volatile organics, which are subsequently removed in degasifying units (e.g. a vacuum degasifier or membrane degasifier). The permeate is then purified to almost the highest theoretical resistivity level by mixed-bed ion exchangers, configured in a merry-go-round arrangement with external regeneration (MOVEX™ technology). Alternatively, the demand for chemical-free treatment may require the application of electro-deionization (EDI) systems.

• External mixed bed regeneration to avoid traces of contaminants in the ultrapure water system
• Modular membrane degasification systems
• State-of-the-art organic removal

The polishing section provides for the final adjustment of the quality parameters, as well as for the temperature and pressure control in the distribution loop. Any remaining TOC is destroyed by LUMOSTIL™ UV units and, to achieve low oxygen levels, an additional degasification system can be employed. All remaining ionic impurities are removed by polishing mixed-bed ion exchangers. Finally, the last remaining particles are removed by ULTRASTIL™ ultra-filtration systems before the ultrapure water is distributed to the cold or hot consumers. 

• Qualified polishing mixed bed ion exchange resins producing ultrapure water with the lowest Boron and Silica concentrations
• Polishing membrane degasification system for Oxygen and Nitrogen removal
• Online monitoring for all critical parameters such as TOC, particles, Silica, Boron, Oxygen, NVR, Ions
• Highest quality ultra-filtration membranes

The ultrapure water is typically distributed to the process equipment on the fab-floor through a looped piping system designed for a continuous flow to avoid bacteria growth. Unconsumed ultrapure water is continuously recirculated to the UPW tank for repurification in the polishing plant. Ovivo provides design, installation, supervision and certification of PVDF and/ or PP distribution systems, including hook-up installations to the process tools.

• Dead lag free design
• Pressure drop optimisation
• Distribution system mass balance
• Qualification/certification

Semiconductor fabrication processes, such as lithography, etching, stripping and cleaning, result in a variety of acid and alkaline waste, metal-bearing waste and organic waste. Specially designed reclaim systems can help in reducing the effluent waste discharge as well as minimizing the raw water needed for the production of ultrapure water whilst protecting the environment. 

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 the conductivity of the rinse water, Ovivo uses systems with or without ion‐exchange stages.

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 systems 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.

• Turnkey systems for highest recycling rates
• Patented TOCSORB® system for high organic rinse water treatment
• Recycling of CMP rinse water

Non reclaimable waste water from the semiconductor manufacturing processes needs to be treated further to meet stringent global discharge regulations. Ovivo has developed several state of the art wastewater treatment processes to meet current and future discharge requirements which help in protecting the environment, conserving resources and meeting new manufacturing challenges as they occur.

Ovivo’s wastewater treatment technology features:

• Lowest chemical consumption
• Lowest cost of ownership
• Fluoride discharge limit <10 ppm

Ovivo’s robust and reliable acid waste neutralization system offers maximum flexibility and efficiency. Ovivo uses a state of the art control system to minimize chemical consumption. Ovivo’s neutralization system has these benefits:

• Lowest chemical consumption
• Robust materials compatible with aggressive chemicals
• Designed for long asset life
• Enhanced reliability

Chemical Mechanical Planarization (CMP) and Back-grinding (BG) are essential processes in semiconductor fabrication. Ovivo treats the resultant wastewater by flocculation and sedimentation to remove slurry particles:

• Hydrogen peroxide control avoids sludge flotation
• Minimal chemical consumption and sludge generation
• Treated water meets stringent discharge requirements
• Designed for long asset life
• Enhanced reliability