How Process Controls Improve Silicon Nitride Wet Etching Result

The silicon nitride wet etching process uses a phosphoric acid solution in water to quickly and effective etch mask material. However, this process is usually hard to control. The etch rate depends on the concentration of the solution and the bath temperature. Ideally, the solution has to be about 85% phosphoric acid and 15% de-ionized water at an optimized temperature of 165 degrees Centigrade. Adding water to the solution to control the concentration will change the temperature, and can be dangerous. Managing such an unstable solution with two interdependent variables is difficult, but using standard controls cannot accurately maintain the etching rate and remove the silicon nitride.


To maintain proper control, small amounts of water are added to the solution continuously, and the solution is maintained at its boiling point. To optimize the process Modutek introduced the silicon nitride wet etching process control solution that improves etch control and results. It features precise control of the temperature, concentration of the solution, and etch rate while ensuring the operation is safely maintained.


Modutek’s control concept uses an always-on heater to keep the 85% phosphoric solution at its boiling point. As water is lost to steam, the solution’s concentration starts to increase, and the temperature begins to rise above the original value. A thermocouple senses the temperature rise and signals the system to add water. A small amount of water is added and immediately mixed into the solution by the boiling action. The concentration is maintained at the original 85% phosphoric acid and 15% water; the temperature remains at the boiling point of 165 degrees Centigrade at this concentration. The etch remains constant and the operation is safe.


An additional thermocouple is located above the hot acid senses the presence of hot steam. Another thermocouple detects the temperature of the acid. If there’s no steam or the acid becomes too hot, the process shuts down. The emergency shutdowns don’t take effect during regular operation, but they are additional safety features in case of equipment malfunction or operator error.


For additional details on how Modutek’s control strategy improves etching rates, read the complete article, “How Process Controls Improve Silicon Nitride Wet Etching Result.” If you have any questions, or would like to set up a free consultation, contact Modutek 866-803-1533 or email


How Wet Bench Stations Are Designed for Ergonomics and Safety

The etching and cleaning silicon wafers involves the use of aggressive and toxic chemicals that needs to be handled carefully. Ergonomic design of wet bench stations ensures safe and comfortable working conditions so employees don’t perform risky or strenuous maneuvers in the normal operation of a facility. The Semiconductor Equipment and Materials International (SEMI) S8-0712 provides safety guidelines for ergonomics engineering of Semiconductor Manufacturing Equipment to help manufacturers design equipment for safe and comfortable operation.

Key safety aspects of semiconductor equipment manufacturing include safe chemical handling as well as fire prevention. The FM 4910 specification and the Cleanroom Materials Flammability Test Protocol help manufacturers avoid using flammable materials in their equipment. Wet bench stations that adhere to these guidelines ensure a better and safer working environment.

Modutek designs its wet bench chemical stations according to the SEMI S8 guidelines and minimizes the use of flammable materials in its designs and construction. Here are the examples of Modutek’s safety and ergonomic design measures:

  • The easy-to-hold wafer holding trays.
  • All Wet Bench Stations are built around your ergonomic requirements.
  • The operator interface is on a swing arm.

Modutek’s wet bench stations are built on a customer’s specifications and incorporate ergonomic safety and repeatability features. Apart from ease of use, Modutek also designs each station around the customer’s facility requirements.

Besides ease of use, Modutek also applies ergonomic design principles and safety features across its full product line of wet process equipment. All of the company’s wet bench stations satisfy safety regulations and are designed to keep an employee’s physical effort to a minimum.

For more details, read the complete article, “How Wet Bench Stations Are Designed for Ergonomics and Safety.” If you would like a free consultation, or have questions, contact Modutek at 866-803-1533 or email


Improving Piranha Etch Process Results in Silicon Wafer Cleaning

Piranha etch, a popular process for silicon wafer cleaning, has to be tightly controlled in order to be effective. It consists of a mixture of about one-part hydrogen peroxide and three parts sulfuric acid, which quickly removes organic matter from silicon wafers. A heated quartz tank is used where both chemical concentration and temperature controls the etch rate.

Maintaining precise control of the original solution is difficult as it is exothermic. The temperature needs to be maintained between 130 and 180 degrees centigrade. The hydrogen peroxide decays to form water, diluting the solution, and the rate of decay depends on how high the temperature is. To prevent the solution from diluting, extra hydrogen peroxide is added to it. However, adding hydrogen peroxide also increases the temperature, which in turn speeds up the diluting process.

The mixture, with periodic spiking of the hydrogen peroxide, has a useful life of only one day. To address this Modutek introduced the “Bleed and Feed” process control strategy that improves the process while reducing chemical use. It also helps increase the useful lifespan of the mixture.

In the “Bleed and Feed” process, Modutek uses a two-tank “clean” and “dirty” tank design. When the hydrogen peroxide concentration in the “dirty” tank decreases, a small amount of mixture is drained from the tank and is replaced by the same amount from the “clean” tank. Then, the “clean” tank takes in a fresh amount of mixture.

The mixtures in the clean and dirty tanks are all programmable so that the desired concentrations can be maintained for an extended period. Using this method leads to the much longer lifespan of the Piranha mixture.

Below are the benefits of using Modutek’s “Bleed and Feed” process control in Piranha etch process:

  • Better control of the process increases the reliability of strip results.
  • Replacing the mixture less often reduces downtime.
  • Chemical purchase and disposal costs become lower.
  • Precise temperature and concentration levels result in a constant strip rate.
  • Programmable dosage levels add control flexibility for predictable results.
  • Reproducing process parameters creates excellent repeatability.
  • Longer mixture life reduces chemical use.
  • The Risk of an accident from adding too much hydrogen peroxide is eliminated.

Learn more about how Modutek continues to improve their silicon wafer cleaning equipment by reading the entire article, “Improving Piranha Etch Process Results in Silicon Wafer Cleaning.” If you have questions, would like a free quote, or to set up a consultation, email Modutek at or call 866-803-1533.

Modutek’s History of Innovation, Customer Support and Satisfaction

Modutek Corporation has been a leading manufacturer of wet bench stations and semiconductor equipment for 40 years. The company continues to work with clients to improve process results and meet their needs.

Modutek emphasizes the three aspects of its operations:

1)   Constant innovation

2)   Customer support

3)   Customer satisfaction

By building its operations around innovation and customer needs, Modutek has become a leading semiconductor equipment manufacturer.

Modutek manufactures high quality and reliable equipment by using quality materials for proven manufacturing processes. When manufacturing wet bench components, Modutek focuses on quality and produces equipment that provides high reliability. High quality and reliable equipment results in low downtimes and quality results.

The company prides itself on developing innovations that provides customers with solutions. By working closely with customers to understand about their needs Modutek provides solutions that incorporate state-of-the-art technology to improve process results.

Modutek is a wet bench manufacturer that designs their wet bench equipment in-house and does not use third parties. Manufacturing takes place in the company’s plant in San Jose, and the software used in the process was also written and programmed in-house by Modutek’s engineers. Customers get high quality reliable equipment as well as exceptional customer service and support.

The company offers a complete line of wet process equipment that includes complete systems, individual stations, and process components. Stations are available in manual, semi-automated, and fully automated, and they can incorporate auxiliary functions such as an IPA vapor dryer or chemical handling station.

Apart from designing and developing standard components, Modutek can also modify its standard designs to meet specific customer needs. Because Modutek builds all of its products in house, it can change dimensions, use special materials, and integrate other functions into a system or program how specific processes run. Combined with their experience and expertise, Modutek can examine customer requirements to develop the corresponding equipment.

Read the complete article, “Modutek’s History of Innovation, Customer Support and Satisfaction,” to learn how Modutek became one of the leading semiconductor equipment manufacturers. If you would like to set up a consultation or get a free quote, contact Modutek at 866-803-1533 or email


Modutek Continues to Supply and Support Customers during Challenging Times

Businesses wishing to continue operations during a crisis, such as the current COVID-19 pandemic, need reliable suppliers to support them. Modutek Corporation is staying open to support its clients, putting the priority on manufacturing critical components for essential businesses and industries. The company has been operating for over 40 years and has weathered many challenges. Being a top supplier in the semiconductor manufacturing industry, Modutek emphasizes equipment performance with lower costs, higher quality to ensure high satisfaction from their customers.

Modutek uses top quality materials for its wet process equipment and manufactures most of its equipment in-house. This ensures that customers get reliable and high quality products that perform consistently over an extended period.

Modutek takes pride in its years of experience and expertise in the semiconductor equipment manufacturing, as well as its experience of working closely with customers. These factors allow Modutek deliver products that will help customers improve manufacturing facility performance. The company focuses on manufacturing quality wet process equipment with low particle counts, increased throughput, reduced defective output, and reduced use of chemicals, all of which benefit customers.

Innovation is what drives Modutek’s product development. New ways of handling wafers, controlling processes, and improving cleanliness produce better results. The company’s innovative approach provides customers with equipment that operates reliably while reducing costs, process steps, and handling while improving output quality.

Aside from supplying quality products, Modutek also provides quality service and support to its customers. The company works closely with its customers and has the required expertise as the company builds its own equipment. Its engineers know how each component works and how the parts combine to deliver the desired performance. Modutek offers manual, semi-automated, and fully automated stations. As for the automation, the company writes its software, without relying on third parties for service. As a result, Modutek can place customer-focused policies using its personnel and can supply effective service with its engineers and technicians.

For more details, read the complete article, “Modutek Continues to Supply and Support Customers during Challenging Times.” For a free quote or consultation contact Modutek at 866-803-1533 or email

Modutek Supplies Components to Essential Businesses During Covid-19 Crisis

modutek-supplies-components-to-essential-businesses-during-covid-19-crisisDuring the Covid-19 pandemic, Modutek continues its business operations because it is a supplier of critical components to essential businesses.

Modutek Corporation supplies parts and systems in wet process semiconductor manufacturing equipment, which are essential for several businesses that include those in the medical and infrastructure industries. It also supports frontline workers by supplying components for face shields used in personal protection equipment (PPE).

Companies whose businesses and manufacturing plants are essential for the continuing operation of vital infrastructure may request that suppliers of critical components be allowed to remain in operation so that they could continue to supply the required parts. The Cyber Security and Infrastructure Security Agency issued the “Memorandum on Identification of Essential Critical Infrastructure Workers During COVID-19 Response” details, which of their activities is deemed essential. Companies may make references to this memorandum. Modutek received the request to remain in operation to support the critical infrastructure.

The medical industry – including health care, medical devices, and PPE’s – face significant challenges posed by the Covid-19 pandemic. Modutek was asked to continue to supply critical components and to ensure that there is enough supply. Some medical devices rely on particular parts and components to work, and Modutek continues to support these manufacturers fully.

As a premier manufacturer of semiconductor wet process equipment, Modutek’s components and subsystems are an essential part of the supply chain for these crucial industries. In normal times, the company supplies components and subsystems to several sectors, and during the COVID-19 pandemic, it continues to support its clients, giving priority to those essential industries.

For more details on this topic, read the complete article, “Modutek Supplies Components to Essential Businesses During Covid-19 Crisis”. If you have questions or would like to discuss your specific requirements, contact Modutek at 866-803-1533 or email

How Chemical Delivery Systems Are Designed to Meet Facility Requirements

how-chemical-delivery-systems-are-designed-to-meet-facility-requirementsDifferent semiconductor manufacturing facilities or other users of chemicals have varying needs and specifications. That is why suppliers of chemical delivery systems need to able to customize their equipment to satisfy the specific requirements at different facilities. Suppliers who also manufacture their equipment in-house are better at adapting their standard products to meet the specific requirements of their clients, compared to third-party manufacturers.

The operation of chemical delivery systems can be divided into storage, delivery, and disposal functions. These functions are influenced by chemical volumes, the number of different chemicals, and facility layout. Operations that require a larger volume of chemicals, storage, and delivery options are different from smaller operations. Other determinants that also impact the execution of the chemical delivery system include the facility’s space and equipment layout. A supplier needs to evaluate all these relevant factors and requirements before designing and building the custom system.

For example, a large operation requiring very few chemicals will only need few and simple controls. A different operation, which involves spiking with some chemicals and mixes others, will require complex controls with high precision. Requirements for repeatability, accuracy and quality control all come into the specifications for the design and configuration of the system. The system provided to a facility needs to incorporate each of these specific requirements.

Operator safety and system reliability are a paramount concern. However, the actual safety features required for the installation may still depend on the kind of chemicals used. Non-hazardous chemicals may not need any special safety measures, while hazardous and inflammable chemicals may require explosion-proof designs that must be certified safe by both the NEC and the NFPA.

In addition, operational strategies must be included to prevent workers from being exposed frequently to chemicals. For this reason, a degree of automation is required to enhance safety and reduce operation error. Semi-automatic and fully automatic systems usually have corresponding safety interlocks and automatic shut-down for dangerous conditions. In every case, the specific operating characteristics of the chemical delivery system must be evaluated and a custom solution needs to be designed and installed.

Read the complete article “How Chemical Delivery Systems Are Designed to Meet Facility Requirements” to learn more. For a free consultation to discuss your specific requirements contact Modutek at 866-803-1533 or email to

How Specialized Manufacturing Equipment Provides Safety for Using Solvents

how-specialized-manufacturing-equipment-provides-safety-for-using-solventsSpecialized 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

Why You Need a Wet Bench Manufacturer with In-House Expertise

As semiconductor manufacturing becomes more complex, the demand for custom solutions is increasing. Standard systems often cannot incorporate the combination of multiple steps required to produce an etched silicon wafer. Instead, they will have inefficiencies as well as lower quality output.

Custom solutions can consider each separate requirement and can assemble a production line in which steps are optimized for peak performance. Wet bench manufacturers with in-house expertise are best situated to satisfy specialized needs for customization since they manufacture the bulk of equipment themselves.

When a company has extensive experience as a wet bench manufacturer, it can evaluate special application requirements, identify key features that will be needed, and use its expertise to design the corresponding equipment. They can design many different custom systems and, along the way, gain experience with the features included in each one.

With the design experience, data gained from testing, and also customer feedback, the company with in-house expertise can design an optimized system without going through a trial-and-error phase. It can also produce a low-cost and easily constructed design. The company uses its in-house design and manufacturing expertise to produce custom solutions that work.

Wet bench manufacturers who can design and build their equipment can also provide customer excellent service and support which promptly address and solve problems. Engineers and technicians who have worked on the equipment won’t have to depend on third-party suppliers and will be able to offer effective solutions.

Modutek has extensive experience and in-house expertise to bring customized solutions to specific applications. The company builds all of its equipment including the design and programming of automation software. It has technicians and engineers familiar with electrical schematics, plumbing diagrams, and software documentation. With its in-house expertise, Modutek can provide the best possible customized designs, equipment, and customer support.

Read the complete article, “Why You Need a Wet Bench Manufacturer with In-House Expertise,” to learn more about Modutek’s in-house capabilities. Contact Modutek for a free consultation or quote at 866-803-1533 or email

Improving the KOH Etching Using Teflon Tanks

Etching with potassium hydroxide (KOH) is commonly used for general purpose etching of silicon wafers. It’s because the process can be tightly controlled, and it is also relatively safe. KOH etching, when done using Modutek’s Teflon tanks, improves the performance through high control accuracy and tight temperature control features on the tank.

The KOH rate is affected by many factors: solution concentration, lattice orientation, doping, and solution temperature. The silicon wafer is masked with a substance such as silicon nitride, which is impervious to KOH. The solution etches the unmasked parts of the silicon wafer. A combination of the measures that affect the etch rate allows operators to etch complex shapes that are used in electronic circuits and microstructures.

A higher concentration leads to an increased etch rate. The KOH concentration can range from about 10% to 50% but is typically around 30% by weight. KOH etching is designed to work with a fixed concentration that is determined at the start of the process and remains in that condition once etching begins.

During the process, the etch rate is controlled through temperature by operators. KOH etching reacts quickly to the temperature changes and the solution temperature can be used to control etching and influence the dimensions of the etched shapes.

Keeping the temperature constant maintains the different etch rates in different directions constant. Changing the temperature also changes the different etch rates and can influence etched shapes. This is why temperature control is crucial in precise KOH etching. A rapid and precise temperature control system can improve KOH etching performance.

Modutek’s Teflon tanks improve KOH etching through tank features such as tight temperature control and high control accuracy. Teflon tanks are designed to eliminate contamination and heated tanks are also available in a circulating design or with an immersion heater in the overflow weir. The tanks are available in standard sizes, but Modutek can manufacture custom sizes as well.

For more details read the complete article, “Improving the KOH Etching Process Using Teflon Tanks.” Contact Modutek to get a quote or consultation on using Teflon tanks as well as other equipment for your manufacturing requirements.