Solvent Processing Using Stainless Steel Stations

Manufacturing processes using volatile solvents have to be specially designed to minimize the risk of explosions or fire. Solvents like acetone or alcohol are used to clean parts, dissolve materials and extract substances.

Safe stainless steel solvent operation depends on specific design measures that reduce the risk of fire or explosion. Modutek provides stainless-steel stations that meet strict safety regulations used in wet bench processing that reduce the risk of ignition of the solvents or their vapors. They have additional features and interlocks in an integrated approach to operator safety. Special safety design measures can include:

• Electrical equipment runs on low voltages and weak currents to reduce the risk from sparks.
• Electric wiring satisfies fire protection standards NFPA 70 and 79.
• Overall station design satisfies hazardous location standards and is certified for Class 1, Division 2 environments.
• The manufacturing process is monitored to detect dangerous conditions such as high temperature.
• Liquid solvent waste is collected in carboys for controlled disposal.
• Safety interlocks eliminate unsafe operation and shut down the process for unsafe conditions.
• Automatic lid operation can seal off chemical containers.
• Operators are trained for safe operation.
• Access controls limit equipment operation to trained personnel.

Modutek's Series SFa and Sa Stainless Steel Stations for solvent processing meet all safety requirements in the applicable regulations. Made of electropolished steel, the stations meet the National Electrical Code Class 1 Division 2 Group D standard for hazardous locations.

The baths feature PVC safety shields, N2 head case purge and an auto lid option. They are designed for operator safety and prioritize safe containment and disposal of volatile solvents. The SFa Series – uses a temperature-controlled re-circulating bath, while the Sa Series is constant temperature.

In addition to the safety measures and temperature control features, the baths have multi-sided heating elements, a 360-degree overflow weir, operating interlocks, process control thermocouples and liquid level sensors. The tanks are available in standard sizes and customized sizes.

Modutek has over 40 years of experience designing wet benches for semiconductor manufacturing. Aa a leading wet bench manufacturer, Modutek works toward advancements to their wet processing equipment, including those with solvent processing stations.

For more details read the published article, Solvent Processing Using Stainless Steel Stations, to learn more. If you need additional information, or would like to schedule a free consultation, contact Modutek by email at modutek@modutek.com or call 866-803-1533.

How Specialized Wet Bench Equipment Improves the RCA Clean Process

The RCA clean process removes contaminants from silicon wafer surfaces with so that additional wet process semiconductor manufacturing steps can occur. Specialized equipment incorporated in wet benches ensures that contaminant and particle removal is complete and silicon surfaces are clean for the next process steps.

The RCA process consists of two steps:

1) RCA Clean SC1 Step Removes Most Wafer Surface Contamination

This cleaning step uses chemicals to dissolve impurities while leaving the underlying silicon surface unaffected. The wafers are placed in a solution containing equal parts of ammonium hydroxide and hydrogen peroxide in five parts of de-ionized (DI) water. The solution is brought to 75 degrees Centigrade, and the wafers are placed in the solution for 10 to 15 minutes. Organic impurities are dissolved, and particles are removed, but a thin layer of silicon oxide forms on the wafer, and there is some contamination with metallic ions and particles.

2) RCA Clean SC2 Removes Impurities

This cleaning step removes metallic impurities. The newly cleaned wafers are placed in a bath containing equal parts of hydrochloric acid and hydrogen peroxide in five parts of DI water. The exact ration may vary depending on the application. The bath is heated to around 75 degrees Centigrade with the wafers soaking for about 10 minutes. Alkali residues, metal hydroxides, and other metallic particles are now removed, leaving the wafers completely clean and free from all kinds of particles.

Wafer cleaning equipment has to meet specialized functions. Specialized equipment is required to carry the RCA process steps effectively. The chemicals required have to be in the right quantities, and then when they're no longer needed, they need to be neutralized and disposed of safely. The concentration of chemicals is also critical, as well as the bath temperature and the timing to achieve the desired cleaning results. Contaminants and particles have to be rinsed off and filtered out. Key characteristics of effective cleaning include a low particle count on the wafer's surface and a resulting low rejection rate for fabricated wafers.

With 40 years of experience as a semiconductor equipment manufacturer Modutek has the experience, to provide the equipment you need for the RCA clean process as well as other semiconductor manufacturing applications.

For more details read the complete article “How Specialized Wet Bench Equipment Improves the RCA Clean Process”. If you would like to discuss your specific needs contact Modutek by calling 866-803-1533 or email Modutek@Modutek.com.

How Specialized Manufacturing Equipment Provides Safety for Using Solvents

Specialized wet bench equipment is used to reduce the risk of fire and explosion from the use of volatile solvents in manufacturing operations. Semiconductor manufacturing facilities use solvents (such as acetone) for various applications such as stripping, cleaning and pattern transfers. Such solvents are inflammable which is why the equipment has to meet stringent safety regulations. Safety measures focus on ensuring electrical components don't cause ignition of solvents or their vapors and operator safety through training.

When inflammable solvents are used safety regulations require specific features and along with operating measures to keep workers safe. Some of the features include the following:

•  Design to hazardous location Class 1 Division 1 or Division 2 certification.

•  Design electrical equipment to use low-power signals too weak to generate sparks that could set off an explosion.

•  Wiring per NFPA 70 and 79.

•  Use of carboys to collect solvent waste.

•  Detection of liquid spills.

•  Process monitoring with safety alarms for dangerous conditions.

•  Emergency power off mushroom button. 

•  Gaseous automatic fire suppression systems such as those using carbon dioxide.

An experienced wet bench equipment manufacturer incorporates these features in all their solvent station designs to ensure an integrated safety concept provides safe operation.

Modutek's stainless steel solvent stations meet all safety requirements. They manufacture the SFa and Sa series of stainless-steel solvent baths for solvent applications including IPA, acetone and resist strippers. The baths meet NEC Class 1 Division 1 Group D requirements for hazardous locations and are specially designed for safe operation. The baths are made of 304 stainless steel and are inert for any kind of solvents used. The SFa bath is a temperature-controlled recirculating bath while the Sa bath is constant temperature.



The SFa and Sa baths have all the required safety features including:

• NFPA 70 and 79 fire warning
• Fire suppression
• N2 head case purge
• 1-inch lip exhaust
• PVC safety shields
• Safety interlocks
• Emergency off mushroom button
• Teflon N2 gun
• De-ionized water hand spray
• Continuous flow de-ionized water manifold

Solvent stations are able to deliver improved yields while maintaining a high level of safety with fast heating and accurate temperature control. Modutek's stations are available in manual, semi-automated and fully automated systems. As a wet bench manufacturer, Modutek is able to both design and build a customized or standard equipment to meet your requirements.



For more details read the complete article, “How Specialized Manufacturing Equipment Provides Safety for Using Solvents”. If you have questions, or would like to set up a free consultation, contact Modutek at 866-803-1533 or email Modutek@modutek.com.

Why Custom Wafer Cassettes Are an Essential Part of Wet Bench Equipment

Wafer cassettes may be customized for use in wet bench equipment to meet specific applications. Research labs and universities may create semiconductor prototypes and start-ups may need sample semiconductors for testing. In each of these cases, off-the-shelf carriers with the required characteristics are usually not available.

Research labs and universities may need wafer carriers with unusual features because they are testing new processes or using new materials. They often need only a few specialized custom cassettes to be able to execute their research and testing. Start-ups also need custom wafer cassettes as they are still developing an innovative semiconductor product. Off-the-shelf wafers may not be suitable as they are not available commercially. To produce different prototypes and test time in real-life situations, start-ups may need a series of custom wafer cassettes before they begin commercial manufacture of their new product.

Modification in the production lines means that some equipment had to be changed and equipment adapted due to various reasons — changes in suppliers, updated regulatory requirements, or new customer demands.

Modutek is a leading manufacturer of wet bench equipment and has the in-house expertise to review customer requirements and provide high-quality custom installations. It offers equipment from the standard line of wet bench stations but can also customize them to meet special equipment (which it designs and builds in-house). When custom wafer cassettes are needed, Modutek can design and build custom units as needed. It can design and build special configurations and use specific materials such as PFA Teflon, PFTE Teflon, PVDF, and Natural Polypro. Custom carriers can hold from one to 25 wafers per carrier and carrier design can be optimized for a specific use. Modutek does not require a minimum order quantity for custom wafer cassettes as its way to emphasize its commitment to meeting the special needs of customers.

For more details read the complete article, “Why Custom Wafer Cassettes Are an Essential Part of Wet Bench Equipment”. If you have questions about custom wafer cassettes for a free consultation or quote contact Modutek at 866–803–1533 or email Modutek@modutek.com.

5 Important Things to Know When Buying Wet Bench Stations

Because of the complicated nature of semiconductor manufacturing, wet benches need to be customized to meet specific requirements for a specific application.

Before focusing on the process-specific requirements, there are general questions that should be answered. They 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. Following this 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 line of wet bench stations can be manual, semi-automatic or fully automated. You get the most benefits from using fully automated stations since they can run batches without operator intervention and provide excellent repeatability if the same product is manufactured multiple times. The use of Modutek's proprietary software will help increase throughput and yield.

2) Stainless Steel Solvent Stations
Modutek's stainless steel solvent stations are available in the manual, semi-automatic and fully automated stations as well as in dry-to-dry configurations. Solvent stations are designed to satisfy fire safety standards that are needed in solvent applications.

3) Chemical Delivery System
Modutek's chemical delivery systems help avoid spills and make tracking of chemical neutralization and disposal easier. The company can also customize the system's design to exactly meet the needs of a customer’s application.

4) Rinsing and Drying
When an etching or cleaning process step is complete, the wafers must be rinsed and dried without leaving any contaminants. Modutek's IPA dryer combines rinsing and drying in one station while the quick dump rinser improves the process efficiently.

5) Special Etching or Cleaning Equipment
Some semiconductor fabrication and research facilities may require specialized wet bench equipment for specific etching or cleaning process steps. For this reason, Modutek can incorporate specialized equipment such as the Vacuum Metal Etcher which is designed to etch aluminum layers with high precision and remove hydrogen bubbles when they are created.

For more details read the complete article “5 Important Things to Know When Buying Wet Bench Stations”. Contact Modutek by email at Modutek@modutek.com or call 866-803-1533 to schedule a free consultation to discuss your needs or get a free quote.

Ordering a Wet Bench Station for Your Specific Process Requirements

Semiconductor equipment manufacturers provide equipment that supports complex manufacturing process steps that must be followed and controlled in a very precise manner. The process requirements will typically include cleaning, etching, developing, and stripping along with the proper handling/disposal of caustic chemicals. The physical attributes required in the production line as well as special features (like recirculation and heating) may also have to be considered.

The three main physical factors that influence wet bench equipment specifications include available facility space, wafer size, and wafer throughput. Limited space for new installations or a requirement to integrate with an existing system may require that compact stations be used. Some functions, like rinsing and drying, can be integrated or may need separate spaces. Chemical delivery systems can take space or be placed some distance away or behind the production line.

Throughput is a crucial variable because this affects profitability. Automatic transfer of wafers between stations and automatic process control may save time. How the process is controlled may affect how long a chemical bath can take place without changing the chemicals and the need for downtime for maintenance.

Wet bench equipment and processes (such as RCA clean and Piranha) use aggressive and often dangerous chemicals. Therefore, the equipment should have a strong resistance to such corrosive substances as well as additional features to keep the operators safe.

These attributes can mean that almost every installation of wet bench equipment is customized to some extent. However, only an experienced semiconductor equipment manufacturer can offer a complete line of wet bench stations incorporating the latest technology and using their own software. A manufacturer should also offer other special features such as heating control accuracy and precise calculation of dosages which are essential for high-quality output. Suppliers who manufacture, assemble and develop their own equipment should also be available for complete after-sales support and service.

For more information read the article “Ordering a Wet Bench Station for Your Specific Process Requirements”. If you want a free consultation or have questions, contact Modutek at Modutek@modutek.com or call 866-803-1533.

Why Chemical Lift Station Pumps Are Needed for Wet Bench Stations

When steps for wet bench processing are done, the remaining chemicals and waste water must be drained and transferred to an area for neutralization and disposal. Depending on the physical layout of a manufacturing facility, gravity draining may not be possible or insufficient due to flow or speed.  Chemical lift station pumps are required in these situations which transfers the chemical solvent in a controlled and optimized method. The use of chemical lift station pumps will enable the fast and complete removal of chemical solvents and waste liquids, leaving the wet benches ready for the new process step.

While designing new installations without lift station pumps and dependence only on gravity drains may be possible, these require facility changes that include upgrades or expansions and retrofitting of pumps. In these cases, chemical lift station pumps must be included in separate stations that are often located at the back of the wet stations. Since these separate stations take up valuable floor space dedicated to productions processes incorporating lift station pumps into new wet bench stations is a better alternative.

Modutek can incorporate lift station pumps into their existing wet bench stations and use them to pump acids, solvents and similar chemicals and solutions in their semiconductor manufacturing equipment. The lift station controls automatically monitor the lift station tanks. The installed level sensors detect the fluids in the in the tank. When the fluids are detected, the corresponding pump is activated to transfer the liquid from the processing station to the facility's neutralization area. Incorporating the lift pumps in the processing stations is an efficient and compact solution for new installations.

The complete article “Why Chemical Lift Station Pumps Are Needed for Wet Bench Stations” explains more details on the use of this equipment.  If you have questions or would like a free consultation please call Modutek at 866-803-1533 or email Modutek@modutek.com.

Why Preventative Maintenance of Wet Bench Equipment is Important

Preventative maintenance of wet bench equipment is necessary and even vital to manufacturers since it helps avoid costly and unexpected downtime due to equipment failure or qualify issues. Wet bench equipment and components are complex and are usually used in a demanding environment. Calibration, cleaning, and replacement of worn-out parts must be performed regularly to maintain facility performance and maintain or improve output quality.

Wet bench stations operate with harsh and corrosive chemicals, and there are also other variables (like temperature) which are also critical for a successful production line. Some parts must be changed, cleaned or serviced regularly while others need to be inspected regularly to determine if any action is required. Scheduling preventive maintenance that limits the downtime for the production line to a minimum while ensuring that all preventive measures are carried out can sometimes become challenging.

The semiconductor manufacturing equipment supplier should specify what preventive maintenance measures are required and which ones are recommendations. Some tasks may be done by the manufacturer's personnel, however, others will require specialists from the supplier. For some lines, production steps are sequential so a specific component may be temporarily at rest for a given time while preventive maintenance is done on that component.

Coordinating with a supplier (who knows about the installation and can handle all preventive maintenance tasks) will help in developing a preventive maintenance program. A supplier can help the semiconductor manufacturer develop and adopt a convenient schedule for a wet bench equipment maintenance program.

Modutek offers this type of maintenance program as part of their customer support. The company has in-house expertise based on almost 40 years of experience in the wet bench processing technology field. Scheduling and implementing a preventive wet bench maintenance program while keeping disruptions to production at a minimum requires using that experienced personnel that Modutek provides.

The complete article, “Why Preventative Maintenance of Wet Bench Equipment Is Important,” explains further about the importance of maintaining wet bench equipment you may have. Call Modutek at 866-803-1533 for a free consultation to discuss your wet bench equipment needs.

How to Safely Use Solvents for Wafer Processing

Solvent wet bench equipment is designed for operations which include substrate cleaning, photoresist stripping, and liftoff pattern transfers. The wet bench stations provide a critical role in the semiconductor fabrication process. Since solvents are often highly inflammable, wet bench equipment needs to be designed to follow stringent safety codes.

Precautions related to fire and electrical safety is some of the most basic requirements in the design of wet bench stations. There are also requirements for safety alarms, carboy collections, heated solvent baths and process timers. Only well trained and authorized individuals should access the wet bench equipment. In many cases, added safety measures from simple approaches, such as using auto-lids made of Teflon or stainless steel used for sealing off chemical containers.

Solvent applications require the use of stainless steel. Modutek's solvent stations are constructed of 304 stainless steel, which makes them suitable for photoresist, IPA and acetone which are critical operations in the wafer processing. Plus, Modutek's solid works and professional flow simulation software provide improvements in productivity.

Modutek's safety design for solvent processing involves every required feature:

• Wiring specified to meet NFPA 70 & 70 codes;
• Emergency power off design for every safety interlock;
• Lip exhausts on all solvent tanks;
• N2 head case purge design;
• Photohelic EPO interlocks;
• Safety shields;
• Teflon N2 guns;
• Continuous flow of the water manifolds;

Modutek's stainless steel solvent stations are available in manual, dry-to-dry, semi-and-fully automated designs. Wet bench design and construction is a complicated process, but Modutek ensures their systems that are designed to meet all industry safety requirements as well as the specific requirements of individual customers.  

Our full article “How to Safely Use Solvents for Wafer Processing” explains more about this topic. Call Modutek at 866-803-1533 if you have questions or would like to get a free consultation or quote.

How Wet Bench Stations Are Tailored for Specific Manufacturing Process Requirements

The fabrication of semiconductor wafers requires precise, closely controlled, and consistently-repeated procedures. These factors are critically important especially for industries that fabricate semiconductors, medical equipment, and photovoltaic cells. They require the use of custom-made wet benches designed to assist the safe and precise control of corrosive chemicals at high temperatures.

Modutek, with over 35 years of experience in wet bench stations, manufactures a full range of wet bench equipment to address the specific needs of semiconductor manufacturing facilities and research centers. Wet bench stations are tailor made based on the manufacturing requirements of each customer. Modutek’s wet bench equipment for the semiconductor industry meets all UL2360/FM4910 standards for fire and contamination safety.

Sulfuric acid-peroxide is a powerful chemical that is critical to the cleaning process applied to semiconductor wafers. Effective application of this chemical mixture is inherently unstable and therefore it needs to be constantly controlled and re-balanced to maintain efficiency.Modutek’s wet bench equipment ensures the precise chemical concentration levels are maintained and insures the most cost-effective use using an exclusive chemical re-use system.

The silicon nitride wet etching process is another semiconductor fabrication stage that is used to mask chemical etchings on silicon wafers. It also requires high precision and control. Once the etching is successfully done, the masking material should be removed. Precise control of certain chemical mixtures used in wet etching (such as phosphoric acid and DI water) will prevent the possibility of dangerous overheating and explosions. Modutek's wet bench stations are constructed with high-tech safety features and the use of precision software to address such challenges.

Read the complete article titled “How Wet Bench Stations Are Tailored for Specific Manufacturing Process Requirements” for additional information about Modutek’s wet bench stations and process control features. If you have questions or would like to discuss your wet bench requirements, please call Modutek at 408-362-2000 or email modutek@modutek.com.

Certifications and Support for Wet Benches and Wet Processing Equipment

Wet benches and wet processing equipment used in semiconductor manufacturing use chemical processing and electrical systems that must be designed to meet industry certifications and compliance standards. Modutek Corporation ensures that their products are designed and manufactured to meet applicable industry standards and also meet the specific requirements of each customer.

Certifications of compliance with applicable standards are a key factor that provides customers the confidence that the equipment they buy is well designed and safe to use in a manufacturing environment. The applicable certifications of compliance include the following:

UL508a Standard for Industrial Control Panels - Defines safety features like protection against live electrical parts and grounding of electrical equipment. The electrical panels in Modutek’s equipment are wired in accordance to this code.

NFPA 70, NEC - Deals with the safety of the design, installation and inspection of electrical systems, and concerns with the current environment and operating conditions of the installation. It also specifically addresses systems in hazardous locations. Modutek’s wet bench stations are wired to fully comply with NFPA 70 and the NEC which provides a high level of safety and operational reliability.   

NFPA 79 - Regulates the electrical safety of industrial machines, as well as their operation. Modutek’s wet benches comply with this standard as well as being designed to provide safe, reliable operation.

In addition to adhering to these standards, Modutek can also supply third-party certification for the above standards as well as for SEMI S2/S8 Safety Assessment, Ashare 110 Fume Hood Testing, AS/NZS3000: 2007 (Australian/New Zealand Standard), CE Mark (European Testing), CSA (Canadian Standards Association). The company guarantees warranty support and excellent customer support for service, repairs, and customization as well, to make sure that clients are completely satisfied with the company's products. For more information read the blog article published on the site titled “Certifications and Support for Wet Benches and Wet Processing Equipment”.