Monthly Archives: October 2019

Selecting the Right Acid Neutralization System for Your Application

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Acid neutralization systems treat the effluent from semiconductor wet process fabrication facilities and other industrial processes to make it safe for release into the environment. The right system for an application will add alkaline chemicals to the acidic solution and raise the pH close to the neutral level of 7 while recording process data to ensure regulatory compliance.

Depending on the type of operation, an acid neutralization system can be selected that either works continuously or in batches. Continuous flow systems treat large volumes of effluent that have a consistent composition and work best with waste water that doesn’t require complex treatment. Batch neutralization systems are often applied to smaller volumes that are difficult to treat. Each kind of system can benefit from full automation to carry out the neutralization process precisely and keep accurate records.

How Acid Neutralization Systems Work

Because releasing untreated acidic waste water is environmentally hazardous and pollutes water ways, governments have imposed regulations on the producers of industrial waste. An acid neutralization system treats and measures the acidity of waste water as it exits the production line. Depending on the process, a suitable neutralizing chemical is added to reduce the acidity. Sensors verify that the neutralization process has reduced the pH of the waste water to a level in keeping with the applicable regulations and the liquid can then be released.

For compliance purposes, keeping a record of treatment and release is extremely important. To enforce the regulations, authorities will often require proof that the prescribed pH levels were maintained at all times. A print-out from a fully automated system showing the process steps that were carried out and the corresponding pH values can be valuable in proving that a company is not the source of any pollution that has been found.

Continuous Flow Neutralization Systems

High volume production lines produce the same components continuously using the same process and produce a constant flow of effluent that varies comparatively little in its composition. These applications are ideally suited to continuous flow acid neutralization systems because the continuous addition of neutralizing chemicals with only a slight variation can easily be controlled and monitored.

The flow can be from a few to several hundred gallons per minute, and once the neutralization requirements are known, the amounts of neutralizing chemicals required can be calculated. The acid neutralization system monitors the input, makes small adjustments to the quantities of neutralizing chemicals to respond to process changes, and monitors the output for compliance with regulations. A record of discharges and their characteristics is available in the form of a digital chart recorder.

Batch Neutralization Systems

In the production of prototypes, the manufacture of small quantities of specialized components and the use of processes that consist of discrete, independent steps produce waste water in small batches that can best be processed by batch neutralization systems. These batches of waste chemicals often need extensive treatment and may require different neutralizing chemicals to meet the allowed discharge pH levels.

Depending on the process and the required neutralizing chemicals, batch neutralization systems can take pH readings, add the calculated chemical doses and then verify that the pH has increased to an acceptable level. In terms of automation and record keeping, the same considerations apply as for continuous flow neutralization systems.

Modutek’s Acid Neutralization Systems

Modutek offers fully automated acid neutralization systems in batch neutralization or continuous flow designs. The compact systems can be customized for specific applications and to fit into an available space. Modutek’s acid neutralization system can be placed indoors or outdoors and can handle flows from 5 to 500 gallons per minute. The microprocessor pH control delivers precise doses of neutralizing chemicals and provides accurate records on a digital chart recorder to prove seamless compliance with discharge regulations. Contact Modutek for a free quote or consultation to discuss your application and acid neutralization requirements.

5 Important Things to Know When Buying Wet Bench Stations

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Because semiconductor manufacturing relies on a large number of process steps and complicated sequencing, wet benches need to be tailored to meet requirements for a specific application. Before focusing on the process-specific requirements, there are general questions that should be answered. This helps narrow down the selection criteria before making the purchasing decision.

General questions include the level of automation, whether stainless steel solvent stations are required, whether a chemical delivery system is needed and whether any special options for rinsing and drying would be beneficial. Any process steps that require special etching or cleaning equipment can then be considered. Such a structured approach helps with selecting the best wet process station configuration and with integrating special equipment within the wet bench station.

1. Automated Wet Bench Stations

Modutek’s product line of wet benches can be fully automated, semi-automatic or manual. Fully automated stations can run batches without operator intervention and offer excellent repeatability if the same product is manufactured several times. Reliable processing with the use of the Modutek SolidWorks Simulation Professional and SolidWorks Flow Simulation software helps increase throughput and yield.

Semi-automatic stations provide the same increased safety and reduction of human error as fully automated stations without the higher price of full automation. Servo-controlled robots provide high precision and reduce handling. Manual stations are a low-cost option that offers all the process features of the automated stations without the robotics and the cost of automation.

2. Stainless Steel Solvent Stations

Modutek stainless steel stations are an excellent solution for solvent applications. They are available in the manual to fully automated versions and in dry-to-dry configurations. Like the acid stations, they can be used with the Modutek SolidWorks Simulation Professional and SolidWorks Flow Simulation software to calculate chemical doses and the process parameters. Solvent station design can include fume hoods and all stations satisfy fire safety standards.

3. Chemical Delivery Systems

Whether a chemical delivery system is needed depends on the volumes and types of chemicals used in the fabricating process. Chemical delivery systems help avoid spills and make tracking of chemical neutralization and disposal easier. Modutek can custom design the system to exactly meet the needs of an application and a key factor for using a chemical delivery system is when high precision is needed for the chemical dosages.

4. Rinsing and Drying

Once an etching or cleaning process step is complete, the wafers have to be rinsed and dried without introducing any contaminants or particles. Rinsing and drying equipment can fulfill special requirements and improve the process. For example, the Modutek IPA dryer combines rinsing and drying in one station while the quick dump rinser improves process efficiency. Both reduce particle contamination and improve process yields.

5. Special Etching or Cleaning Equipment

Some semiconductor fabrication may require special equipment for specific etching or cleaning process steps. For example, etching of aluminum layers on wafers or the removal of submicron particles can be carried out with wet bench equipment that Modutek has specifically designed for the purpose. Modutek’s Vacuum Metal Etcher automatically etches aluminum layers with great precision and immediately removes hydrogen bubbles as they are generated. In addition Modutek can incorporate the use of Megasonic cleaning equipment to dislodge and remove the tiniest particles from wafers to be processed. This and other kinds of specialized equipment can be integrated into the process line of a wet bench.

Modutek Can Help With the Final Selection

Once customers know the things mentioned above and the requirements of their wet process application, Modutek can suggest appropriate solutions from their complete line of wet process equipment. The company designs and builds all its own equipment and meets standard industry certifications of compliance. Because the work is all done in house, Modutek can customize equipment easily and can offer outstanding customer support and service. All equipment is tested before delivery and includes a comprehensive warranty.