Chemical Handling for Wet Processing Equipment

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Chemical Handling for Wet Processing EquipmentBecause wet processing of silicon wafers uses different types of chemicals, semiconductor manufacturing facilities need chemical handling equipment to store, deliver and dispose of the chemicals. A complete chemical handling system takes care of all aspects of chemical use and ensures chemicals are delivered to the process when and where needed.

For corrosive, toxic, or flammable chemicals, safe handling is critical. Most of the chemicals used in wet processing can’t be released into the environment without additional treatment. Neutralizing dangerous chemicals on site or storing them in safe containers until they can be transported to a treatment facility must be documented to comply with local regulations.

Since chemicals are often dangerous to the employees operating wet processing systems, the chemical handling equipment has to be designed to minimize spills and reduce employee exposure to chemicals and their fumes. A comprehensive chemical handling system can improve workplace safety, reduce spills and waste, and make chemical processes more efficient.

Chemical Delivery Systems Provides Your Process the Chemicals It Needs

Chemical delivery systems store the chemicals safely and then deliver the right quantities, mixtures, and concentrations directly to the production line. The amount of chemicals delivered has to be precise and repeatable. Successful wet processing often depends on the right mixture or concentration because etching, stripping, and cleaning can vary with the amount of chemicals in the bath. When processing batches, the amounts delivered must be precisely the same for each batch. With continuous processing, the chemicals delivered can’t vary over time.

Modutek has a complete range of chemical delivery equipment, from high volume systems for large continuous production lines to small batch operations. Chemicals can be stored remotely in large totes with a load cell interface or in 55-gallon drums near the wet process station. Modutek’s SolidWorks Simulation Professional and SolidWorks Flow Simulation applications can calculate the exact quantities of chemicals required, and the chemical delivery systems provide precisely the calculated amounts. These systems ensure that chemical handling and process repeatability are excellent.

Modutek’s Collection Systems Remove Used Chemicals from Processing Stations

Once a wet process such as cleaning, etching, or stripping is complete, the used chemicals must be removed from the process stations and collected. Chemicals can be stored in safe containers and sent to a company specializing in neutralizing and disposing of hazardous chemicals, or they may be neutralized on-site.

To collect the chemicals from processing stations, chemical lift stations can pump the chemical waste from the process tank to a storage container. Chemical carts, also called pump carts or collection carts, can be moved near the process tanks to empty smaller amounts of chemicals. Storage can range from small carboys to large collection tanks. For small volumes, waste chemicals can be pumped directly into a five-gallon DOT-approved carboy for subsequent shipping to an off-site neutralization facility.

Acid Neutralization Systems Ensure Compliance with Environmental Standards

Many wet process semiconductor manufacturing steps use strong acids in their process baths. The used acids must be disposed of safely without risks to employees, the general public, or the environment. Local regulations specify how acid waste must be treated to ensure that disposal meets these requirements.

As regulatory compliance becomes more complex, the costs of disposing of chemical waste off-site are increasing. Modutek can provide self-contained acid neutralization systems that are inexpensive to operate. These systems add neutralizing chemicals to the acid waste and track chemical use, waste pH, and discharge quantities. The systems can generate documentation for regulatory compliance and safely dispose of the neutralized waste.

Modutek Offers In-House Expertise for Selecting Chemical Handling Equipment

Modutek can help customers choose the right chemical handling equipment for their facility. In-house experts at Modutek can recommend equipment from a full line of chemical handling systems. Modutek can customize equipment for special applications and ensure that the systems meet customer needs. Contact Modutek today for t a free consultation to discuss your chemical handling needs.

Easy to Install Wet Processing Equipment for R & D

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Easy to Install Wet Processing Equipment for R&DWhen research labs need to produce semiconductor prototypes or small quantities for testing, it’s often too expensive to place an order with a wet process production line supplier or to purchase complete wet process stations. Modutek has developed innovative tabletop models that are less expensive than full-sized wet process manual stations and take up much less room. They support the most common wet process cleaning, etching, and stripping steps, and Modutek can customize the units for special applications. The new Modutek tabletop units are easy to install and ideal for small-quantity R&D applications.

Modutek’s Table Top Units Are Feature-Rich and Versatile

Modutek has designed its new tabletop wet processing units to satisfy various R&D needs. The Teflon tank models support acid process steps such as KOH etch and buffered oxide etch (BOE), while stainless steel models support solvent process steps such as solvent resist strip. Tanks are available for ambient temperature or temperature-controlled operation, and they can be static or re-circulating with a filter and an all-Teflon fluid path. The temperature-controlled models have precise controls with rapid and even heating of the bath. The tanks come with temperature and level alarms and a drain interlock.

The compact and simple design of the tanks makes them easy to use, and operators can quickly get excellent results. The standard units that support the most common wet process steps allow the production of many different types of semiconductors. Modutek can customize its tabletop units to support additional silicon wet etching processes as required.

Modutek’s Table Top Units Support KOH Etch

KOH etching is popular because it delivers precise results using a relatively safe process. As such, it is well-suited for tabletop R&D applications. The etch rate depends on potassium hydroxide (KOH) concentration and temperature in the process solution. The etch direction can also be influenced by the silicon lattice’s orientation and the silicon’s boron doping. Different etch control strategies allow operators to etch various shapes into the silicon wafer.

The concentration of KOH may vary from 10 percent to 50 percent, but it is usually at around 30 percent. The orientation of the silicon crystal lattice means that the etch rate is faster in one direction, and Boron doping stops the etch progress in the direction in which the boron is found. These control factors are determined by the design of the etch shapes before the start of the process. Once etching has begun, the temperature allows operators to further control the etch rate and influence the shapes of the etched cavities. Because KOH etches can be controlled in different ways, it is the etch process most commonly used in Modutek’s tabletop units.

Using Modutek’s Table Top Units for Sub-Ambient BOE Etch and Solvent Applications

BOE etching is used to etch patterns in silicon dioxide films or to remove such films from the silicon wafer surfaces. The etching solution contains hydrofluoric acid, and a low temperature reduces consumption. The units that support BOE are the circulating, filtered models that are also fitted with a heater/chiller. Sub-ambient operation down to 10 degrees centigrade is possible.

Solvents used in semiconductor manufacturing steps, such as solvent resist strip, require stainless steel tanks and special safety features. Solvents, such as acetone, are flammable, and Modutek’s tabletop units include measures to prevent fire and explosions. Modutek can customize solvent and acid tabletop units to support other wet-process applications and add special features as needed.

Modutek Can Provide Custom Units for R&D Applications

Modutek has extensive in-house experience designing and building silicon wet etching equipment. If you need equipment to support R&D functions, tabletop units are an excellent option that can be customized to support many wet-process applications. Contact Modutek for a free consultation to discuss your application requirements.

Equipment Innovations Improve Silicon Nitride Etch Processing

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Equipment Innovations Improve Silicon Nitride Etch ProcessingWhen silicon nitride wet etching is used to etch masks on silicon wafers, precise control of the etch rate is important. If the etch rate varies, the mask may not be correct and the microscopic structures to be created in the silicon may not have the right shape or depth. In the silicon nitride wet etching process, the etch rate depends on both the temperature and the concentration of the etching solution. Both may vary as the process progresses and precise control becomes difficult. An ideal control strategy maintains both the concentration and the temperature at known levels. The etch rate then remains constant and the mask is etched accurately according to the applicable specification.

Silicon Nitride Mask Etching Is Effective but Hard to Handle Safely

Semiconductor manufacturers and research labs use silicon nitride wet etching because the process etches the mask material quickly and reliably. A mixture of 85 percent phosphoric acid and 15 percent deionized water is heated to the boiling point. As the mixture boils, it releases steam that reduces the amount of water in the etching solution. As the concentration of phosphoric acid rises, so does the boiling point, the temperature of the mixture and the etch rate. To keep the process under control, deionized water has to be added to bring the concentration back down.

Adding water to phosphoric acid is exothermic. To prevent a sudden increase in temperature, water has to be added in small amounts, but if too many small amounts are added to the mixture, it will stop boiling. The water then forms a thin film on top of the mixture and eventually mixes with the phosphoric acid all at once, leading to a sudden temperature spike and a possible explosion. A complex control system with variable set points can ensure safe operation but control of the etch rate is poor.

Modutek’s Silicon Nitride Etch Controls Are Simple and Precise

Modutek addresses the control issues of silicon nitride wet etching by heating the etch bath continuously. An always-on heater heats the original 85/15 percent phosphoric acid/deionized water mixture to its boiling point of 165 degrees centigrade. As the mixture loses steam and the concentration and temperature both start to rise, a thermocouple detects the slightly increased temperature and triggers the addition of a small amount of deionized water. The added water is immediately mixed into the etching solution by the boiling action. The amount added restores the concentration and keeps the temperature at the boiling point.

Modutek has refined this control concept to accurately maintain the etching solution exactly at its original concentration and at its boiling point. As a result, with both the concentration and the temperature remaining constant, the etch rate remains predictable and constant as well. Mask etching is reliable and the final mask has precisely the desired characteristics.

Because the Modutek control strategy relies on maintaining the etching solution at the boiling point, the control system has additional safety features to identify dangerous conditions that could result if the mixture stops boiling. Two thermocouples detect the presence of steam over the hot acid and acid overtemperature. If there is no steam, the mixture is no longer boiling. If the acid temperature is too high, the solution is no longer being maintained at the original boiling point. In either case, the process is shut down because equipment failure is likely and a dangerous condition may be present.

Modutek Provides a Complete line Equipment Solutions

Modutek offers a complete line of silicon wet etching equipment and works with customers to develop innovative solutions to their problems. The silicon nitride etching control system improves etching performance and results remain consistent over different batches. The number of defective products is reduced and product quality increases. When customers purchase etching systems and other equipment, Modutek will ensure they meet their requirements. Contact Modutek for a free consultation to discuss your specific process requirements.

How Advanced Ozone Cleaning Reduces Costs and Improves Wafer Yields

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How Advanced Ozone Cleaning Reduces Costs and Improves Wafer YieldsWhen ozone is used to clean silicon wafers, it reduces the use of aggressive chemicals and it can decrease the wafer particle count. Modutek’s advanced ozone cleaning process can clean more quickly than many chemical-based processes and it delivers other benefits. Ozone is used to remove organic contaminants from wafer surfaces in either the Coldstrip sub ambient process or the Organostrip process. Either process can reduce overall wafer fabrication costs and improve manufacturing facility performance.

Advanced Ozone Cleaning Outperforms Chemical Stripping

With increased regulation of the use of dangerous chemicals and pressure on businesses to make their operations more environmentally friendly, Modutek developed the advanced ozone cleaning processes to help semiconductor manufacturers and research labs reduce chemical use. Ozone is introduced in Modutek’s DryZone system in compact units using the Coldstrip or Organo strip processes. Both cleaning methods also feature a reduced particle count compared to chemical cleaning methods.

In the Coldstrip process, wafers are first rinsed with deionized water to remove soluble non-organic contaminants. The process operates at four to ten degrees centigrade. After the rinsing, ozone is introduced into the chamber and combines with the carbon of the organic compounds on the wafer surfaces. The ozone-carbon reaction forms carbon dioxide, leaving wafers clean and almost free of particles.

The Organostrip process also uses ozone but operates at ambient temperature. Ozone is introduced into the process dissolved in acetic acid, a mild solvent in which ozone has a very high solubility. The wafers are rinsed with the ozone-acetic acid solution and the high level of ozone rapidly oxidizes the organic contaminants. The waste products of the process do not require special treatment. Both processes work quickly and feature excellent cleaning performance with low particle counts.

Changing to the Advanced Ozone Cleaning Process Delivers Substantial Benefits

The major benefits of changing from chemical cleaning to an advanced ozone cleaning process is a reduction in the use of toxic chemicals and improved cleaning performance with a lower particle count. These two factors are at the root of additional benefits resulting in cost savings, better yields and improved safety for employees.

Reduced Use of Chemicals

When the use of toxic chemicals is reduced, there are cost reductions in addition to savings resulting from fewer chemical purchases. Other savings include reduced costs for chemical storage, handling and disposal. Employees benefit from lower exposure to harmful chemicals and from increased workplace safety because there is less danger of spills or accidents.

Regulatory compliance costs are also reduced. As environmental regulations become more onerous, costs rise and compliance becomes more difficult. Reduced chemical use results in lower compliance costs, and a more environmentally friendly operation helps improve community relations and the environmental reputation of the business.

Lower Particle Contamination

Lower particle counts are the result of better cleaning performance. Particle counts play ang increasingly important role in wafer structures that are smaller and more tightly packed. Even a single particle can block a conducting path or the etching of a tiny detail. Fewer particles means a lower rate of defective products and higher yields. Product quality and longevity may also be improved.

Improved Cleaning Performance and Wafer Yields with Less Equipment

In addition to a lower particle count, the improved cleaning performance of the advanced ozone cleaning process results in shorter cleaning times within a smaller footprint. Modutek’s DryZone units used for the ozone cleaning process are compact and take up less space than the corresponding chemical cleaning stations. Cleaning is more rapid resulting in higher throughput. As a result of these benefits, the overall performance of the silicon wafer fabrication facility can improve substantially.

Modutek Provides Advanced Equipment for Manufacturers

As one of the leading semiconductor equipment manufacturers, Modutek can advise customers on how to implement a change to ozone cleaning. Modutek offers a free consultation and quote on their equipment, and ensures their equipment will support processes that meet customer requirements.

Why Stainless-Steel Stations Are Needed for Solvent Processing

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During silicon wafer fabrication, BEOL (Back End of Line) processes may require solvent-based stations to ensure compatibility with semiconductor manufacturing steps. FEOL (Front End of Line) acid-based chemistry may not be suitable for BEOL finishing. Instead, stainless-steel stations with solvents such as acetone, IPA (Isopropyl Alcohol) or EDP (Ethylenediamine Pyrocatechol) complete wafer etching, stripping, and cleaning. Stainless steel is used for these stations because it is impervious to solvents and because it reduces the risk of fire when solvents are highly inflammable.

Why BEOL Wafer Fabrication Steps May Require Solvent-Based Stations

A wet bench FEOL fabrication starts by repeatedly cleaning, etching, and stripping wafers to build microscopic structures in the silicon. The common acid-based processes used include RCA clean, with chemicals such as hydrogen peroxide and hydrochloric acid; KOH etch, with potassium hydroxide; and Piranha clean, with sulfuric acid. As well as etching the silicon wafers, these chemicals remove both organic and metallic impurities from the surfaces of the wafers, leaving them completely clean and pure for the next process steps. The structures etched during these FEOL steps form the physical parts of the semiconductor components such as transistors.

In the BEOL process steps, the transistors and other components are interconnected and connected to plugs or sockets that interface with outside signals. The connecting paths are metallic, usually made of copper or aluminum, so that they can conduct electrical charges efficiently. Once the metallic paths are deposited on the silicon wafers, acid-based processes can no longer be used because the acidic chemicals damage the metallic paths. Instead, a solvent manufacturing process is used with solvents that are compatible with metals but can complete the silicon wafer processing and produce the final semiconductor components.

Solvent-Based Wet Benches Need Special Safeguards and Protection

The solvents used in wet bench stations are highly inflammable and operators have to be protected against being exposed to fumes or contact. Stainless steel stations using inflammable solvents have to be explosion-proof and satisfy the Class 1, Division 2, Group D explosion-proof standards. They should be designed with fire suppression and wired to the NFPA 70 and 79 standards. An emergency power off mushroom button with safety interlocks helps protect operators if something goes wrong and PVC safety shields help prevent accidental contact with the chemicals. An experienced wet bench manufacturer can ensure that these safety regulations are followed and that operating the solvent stations is as safe as possible.

Modutek’s Stainless Steel Solvent Stations Operate Safely and Meet Customer Requirements

With over 30 years of experience in wet process technology, Modutek designs and builds stainless steel solvent stations to operate safely and meet customer requirements. These stations are made of 304 stainless steel and are wired to the NFPA 70& 79 standards. Fire suppression is included and extensive customization is available.

Stations can be fully automated, semi-automatic, or manual. Fully automated stations reduce operator error and feature excellent repeatability, both for batch processing and for keeping variables constant over an extended period of continuous operation. Semi-automatic stations provide many of the benefits of fully automated operation but at a lower cost. Manual operation is ideal for testing or for prototypes. Once the process has been optimized with manual adjustments, automatic operation can reduce defects and improve facility performance. SolidWorks Simulation software is available to analyze the process and calculate chemical flows. The software can improve etching performance, improve yields and increase throughput.

On the performance side, Modutek stainless steel stations can operate with temperatures from thirty to one hundred degrees centigrade, heat up the bath at a rate of 2 degrees centigrade per minute, and maintain the temperature with an accuracy of plus/minus 1 degree centigrade. Heating elements are four-sided and a process temperature controller is available as an option.

Modutek’s Expertise in Wet Process Equipment

 Modutek designs and builds their own wet process equipment in-house using their own expertise and experience. Their wet bench equipment is designed to meet high quality standards, and are customized to meet specific customer requirements. Solvent-based stainless-steel stations deliver top performance for BEOL processing and Modutek can ensure the equipment meets specific customer needs. Contact Modutek for a free consultation to discuss your specific process requirements.

How the Piranha Etch Process Improves Silicon Wafer Cleaning

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While the Piranha solution quickly removes organic residue from silicon wafers, the process is difficult to control and may produce explosive gas mixtures. The Piranha solution is made up of one part hydrogen peroxide and three parts sulfuric acid, although the ratio may vary for specific applications.

The mixture is exothermic and the heat released when the hydrogen peroxide is added to the sulfuric acid drives up the temperature of the solution towards the normal process operating temperature of 130 to 180 degrees centigrade. Both the temperature and the concentration may vary, reducing the useful lifespan of the solution. When the challenge to control temperature and maintain the concentration is met, the Piranha solution can deliver superior silicon wafer cleaning performance.

Spiking the Piranha Solution Can help Maintain Concentration

The hydrogen peroxide in the Piranha solution is not stable and decomposes to produce water. The rate of decomposition is higher the higher the temperature, and the water dilutes the solution. Operators can compensate for the lower concentration by periodically spiking the solution with additional hydrogen peroxide. As hydrogen peroxide is added, the temperature rises, and more hydrogen peroxide decomposes to form water. This interdependence of the concentration with the temperature complicates keeping a tight control on the process, but spiking the Piranha solution lengthens the solution’s lifespan from a few hours to about one day.

Modutek’s “Bleed and Feed” Method Increases the Piranha Solution Lifespan

Modutek has developed an innovative solution to the control and lifespan issues of the Piranha process. The company uses quartz tanks with a “clean” and a “dirty” tank to provide pre-mixed Piranha solution to the active process. Silicon wafer cleaning takes place in the “dirty” tank while the clean tank has a Piranha solution with a programmable concentration. When the concentration of hydrogen peroxide drops in the “dirty” tank, a small amount of the low-concentration solution is drained from the tank and an equal amount is added from the “clean” tank. Instead of the destabilizing spike of hydrogen peroxide, the small but frequent addition of pre-mixed fresh Piranha solution keeps both the concentration and temperature stable and makes possible a tight control of the process, significantly prolonging lifespan.

The “Bleed and Feed” Method Delivers Important Benefits

Modutek’s “Bleed and Feed” method is fully programmable, allowing operators to adapt it to any application to deliver improved silicon wafer cleaning. The concentrations of the “clean” and “dirty” tanks, the amount of the “bleed” and the amount of the “feed” are all independently adjustable so the desired concentrations can be maintained for an extended period. Specific benefits of the “bleed and feed” method include the following:

  • Predictable strip rate because both the temperature and the concentration are tightly controlled.
  • Programmable settings allow a flexible operation.
  • Risk of an explosion from spiking with too much hydrogen peroxide is reduced.
  • Longer solution lifespan results in reduced use of chemicals.
  • Reduced costs for purchase, storage, and disposal of chemicals.
  • Reliable process parameters result in excellent repeatability between batches and accurate maintenance of process variables over extended operation.
  • Reduced downtime because the Piranha solution has to be replaced less often.
  • Safer operation because the process is maintained in a stable equilibrium.

With a more stable Piranha process, silicon wafer cleaning is improved with less contamination and fewer particles. Product defect rates are lower and customers will see higher yields. Overall wet process line performance is improved, with lower costs and better output quality.

Modutek Provides Innovative Solutions for Wet Processing Requirements

Modutek continues to build on its experience in wet process technology and has in house expertise to develop innovative solutions for their customers. The Piranha solution “bleed and feed” method lets customers achieve their production goals more easily. Modutek provides solutions that meet customer needs and ensures that the delivered equipment performs as required. Contact Modutek for a free consultation to discuss the equipment needed to support your specific process requirements.

How Quick Dump Rinsers Improve Wet Processing Results

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While effective and rapid rinsing with a low particle count remains a key benefit of quick dump rinsers, reduced water usage is also becoming more important. Special design measures can lower the amount of water required to rinse the silicon wafers while retaining fast and efficient operation with a low level of particle contamination.

Low water consumption is especially important in some regions such as the Western U.S., where a long-term drought makes water conservation mandatory. Even in other areas, a reduced use of the deionized water used in silicon wafer fabrication saves money and is environmentally responsible. Modutek has pioneered the design of quick dump rinsers that feature efficient use of deionized water, fast operation, and low particle entrapment.

Quick Dump Rinser Benefits that Incorporate Reduced Water Usage

Modutek’s quick dump rinsers feature a state-of-the-art design for efficient operation while minimizing rinse time, reducing the particle count, and keeping deionized water usage to a minimum. Modutek’s quick dump rinsers offer the following characteristics:

  • Efficient Rinsing. The units have dual spray manifolds and low misting nozzles for quick and complete rinsing away of chemical residues.
  • Nitrogen Bubbler. The bubbler generates nitrogen bubbles as the tank fills, removing additional contaminants and particles.
  • 360 Degree Overflow Weir. As the dislodged impurities rise to the surface, they are flushed away across the overflow weir and out of the tank.
  • Programmable Water Use. Modutek’s quick dump rinsers can be programmed to use less water.
  • Contoured Bottom. The rinser bottom is contoured around a wafer cassette, reducing the amount of water required.
  • Large Machined Trap Door. The machined trap door doesn’t need gaskets or seals that could trap particles, and the large size lets water drain rapidly.
  • Polypropylene Construction. High-quality smooth polypropylene construction ensures that the tank is not a source of contamination with new particles.
  • Automatic Dump and Refill. The rinsing controller can be set to automatically dump and refill every two hours, reducing bacterial growth and minimizing the possibility of contamination.
  • Optional Reclaim System. An optional reclaim system further reduces water consumption and lowers costs.
  • Variety of Standard Sizes. Modutek offers seven standard tank sizes for their quick dump rinsers, and can accommodate many special customer needs.

Modutek has designed the quick dump rinser to operate as a stand-alone unit or for integration into a silicon wet etching process line. The rinser can improve the overall performance of the line and lower costs while reducing the number of defective products.

Benefits of Using Modutek’s Quick Dump Rinser

Modutek’s design is based on extensive experience working with wet process equipment to address key customer concerns. Benefits include the following:

  • The reduced water consumption due to rapid rinsing and a water-conserving design lowers costs and reduces the environmental impact.
  • The machined trap door and laminar flow of rinsing water reduce the particle count and improve output quality.
  • The smooth polypropylene construction avoids additional contamination and reduces the percentage of rejects.
  • Quick rinsing allows increased throughput for the production line and reduces costs.

From its close working relationship with customers, Modutek can address the challenges manufacturers often have with meeting higher product densities, smaller silicon structures, and increasing regulation with using chemicals and water. Modutek continuously works to improve silicon wafer processing capabilities, while keeping in mind the overall costs of ownership and efficient wafer processing.

Modutek Provides Innovative Solutions to Meet Customer Needs

Modutek’s quick dump rinsers represent years of innovative design and development. These systems let semiconductor manufacturers and research facilities reduce water consumption while increasing output and reducing the number of product defects. Overall facility performance is improved through cost reduction and improved output quality. Contact Modutek for a free quote or consultation to discuss your specific processing requirements at 866-803-1533 or email [email protected].

How to Select an Acid Neutralization System to Reduce Chemical Disposal

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When industrial processes such as semiconductor manufacturing use chemicals, the chemical waste needs to be treated before disposal. Chemical waste treatment can be handled on-site with an acid neutralization system or companies can use outside service providers to pick up the waste and properly dispose of it.

Modutek’s acid neutralization systems are designed for easy and flexible installation along with reliable operation and low chemical consumption. The systems make it easy for customers to avoid the costs of hiring disposal companies by treating chemical waste in-house. For many industrial processes, the chemical waste treated with an acid neutralization system is safe enough to drain into the local sewer system.

Continuous Flow Versus Batch Neutralization Systems

For most large industrial operations, a continuous flow acid neutralization system is the best solution. The waste chemicals from a process are produced continuously and they are automatically treated. A continuous flow of 5 to 100 gallons per minute (GPM) can be neutralized. Smaller industrial facilities often operate in batch mode where small quantities of used chemicals need to be disposed of. Modutek’s acid neutralization systems treat and neutralize chemicals using the continuous flow method.

Flexible Installation Means Modutek Systems Are Suited for Many Different Applications

To reduce chemical disposal via an outside service provider, an in-house neutralization system has to be flexible and easy to install. Cost-effective systems have to feature low chemical consumption for complete neutralization allowing disposal into a local sewer. Modutek’s acid neutralization systems satisfy these requirements and can save customers money by reducing chemical disposal costs.

Additional installation features for various service applications include the following:

  • Indoor or outdoor installation
  • Working volume up 4000 gallons
  • 110% Secondary containment tank for extra safety
  • Final discharge sample tank with pH probe and chart recorder for compliance purposes
  • Acidic or alkaline chemical waste treatment in two or three stages
  • Fully automatic operation with a touch screen monitor
  • Unitized construction with larger systems skid-mounted
  • Microprocessor-based pH controls with a comprehensive alarm system

Modutek’s acid neutralization systems are designed to fit into existing process lines with just a plumbing connection and electrical hookup. Once installed, the systems offer problem-free chemical waste neutralization and disposal.

Sensors, Meters, and Automation Help with Ease of Operation

Modutek acid neutralization systems are designed to work reliably in fully automated mode while sensing chemical waste composition and triggering alarms when key variables show abnormal values. Electronic chemical metering pumps supply the correct amounts of neutralizing chemicals while Signet pH probes and transmitters monitor the composition of the chemical waste. Signet paddle wheel flow sensors and signet 9900 flow meters/totalizers send their signals back to a PLC that controls alarms. The systems are designed to work independently while providing readouts for operators tracking the process. Chemical use, discharge pH, overall flow, and triggered alarms are recorded. Operators can make sure that discharged waste stays within the environmental regulatory framework and can use the recorded data to demonstrate compliance with proscribed values.

Modutek’s Expertise in Chemical Processing and Neutralization

By working closely with customers and industry partners, Modutek provides continuous innovative products to meet customer needs. Modutek has its own in-house expertise to evaluate specific applications and make recommendations. After identifying process requirements, Modutek can make suggestions and offer systems from its complete line of chemical handling equipment. For a free quote or consultation to discuss your chemical processing and neutralization requirements contact Modutek at 866-803-1533 or email [email protected].

How Optimum Particle Reduction is Achieved in a Wet Bench Process

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When microscopic particles remain on the surface of silicon wafers during a wet bench process, the resulting semiconductor products may be of reduced quality or even defective. As semiconductor geometries and microscopic structures become smaller and are packed more densely on a silicon wafer, the presence of particles can influence the etch rate around the particle and compromise semiconductor fabrication. The smallest structures and conductor paths can be influenced by particles in the submicron size range and these particles are especially difficult to remove completely.

Modutek has developed innovative solutions that achieve particle reduction through reduced handling of wafers and excellent particle removal. The single chamber IPA Vapor Dryer and the use of megasonic cleaning deliver excellent results. The reduced particle count produces better yields and higher quality output. At the same time, Modutek’s solutions save money through the reduced use of chemicals.

The Single Chamber IPA Vapor Dryer Keeps the Particle Count Low

Modutek’s single chamber IPA Vapor Dryer incorporates rinsing and drying in a single system to save space, reduce costs, and minimize the handling of silicon wafers. The system initially rinses the wafers with de-ionized water and then introduces IPA vapor into the drying cabinet. The vapor comes from a one-gallon bottle that is located in the exhaust compartment for easy changing.

IPA vapor is introduced into the drying chamber from the top to ensure even distribution and reduce the amount of IPA required. When the IPA vapor condenses on the wafers, a surface tension gradient develops between the IPA and the remaining water. When water flows off the wafer surfaces it can remove the contaminating particles. The dry wafer surface doesn’t have any water marks and no particles are added.

One source of particles is the handling of wafers during transfers between stations. Reducing the number of transfers eliminates a source of particle contamination. Modutek’s Single Chamber IPA Vapor Dryer can handle an optional etching feature and drying in the same system. The wafers are rinsed and dried without transferring them to a new station. Since no additional particles are introduced during this process the particle count is kept to a minimum.

Megasonic Cleaning Effectively Removes Particles Without Toxic Chemicals

Megasonic cleaning relies on high-frequency sound waves in the cleaning solution to remove contaminating particles from wafer surfaces. Modutek has partnered with Kaijo Corporation, a world leader in megasonic cleaning systems to incorporate this technology in their wet bench equipment.

A megasonic generator feeds a high-frequency signal to a transducer immersed in the cleaning tank liquid. The transducer converts the signal into sound waves that travel throughout the tank. The sound waves generate microscopic cavitation bubbles that produce a scrubbing action to clean wafers. Particles on the surface of the wafer are dislodged and washed away.

The higher the megasonic frequency, the smaller the cavitation bubbles and the gentler the cleaning action. The microscopic structures etched into silicon wafers are very delicate and could be damaged with rough cleaning. Megasonic cleaning uses frequencies of 950 kHz and higher. The tiny bubbles of megasonic cleaning deliver gentle cleaning action without damaging fragile silicon structures.

Although megasonic cleaning works well with DI water or an SC1 process, adding a mild detergent or solvent can improve cleaning performance. Particles on silicon wafer surfaces often adhere to the surface and can be difficult to remove. Submicron particles may stay within a surface boundary layer, resisting removal. The microscopic bubbles can dislodge such particles, but the addition of solvents or detergents helps dissolve the bonds holding the particles to the surface and can improve particle removal.

Modutek Innovates to Help Meet Customer Challenges

Modutek works closely with customers to identify issues with wet process applications and continually works on developing new innovative solutions. The Single Chamber IPA Vapor Dryer and the megasonic cleaning process are innovations that help reduce particle counts while reducing chemical use and lowering costs. Modutek’s experience with wet processing equipment ensures customers will continually be able to improve their process performance results. Contact Modutek to schedule a free consultation to discuss your specific process requirements.

How Software Controls Achieve Best Results in Silicon Wafer Processing

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Depending on the degree of automation, software controls can enhance wafer manufacturing facility performance and achieve improved results. Full automation lets operators take advantage of different operational modes to test new process steps and optimize process variables. The controls can then run the process with precise repeatability and often without operator intervention. The reduction in operator error, monitoring chemical concentration with dosing capability and the increased reliability can result in higher yields and reduced costs with more efficient silicon wafer processing.

Automation controls in wafer manufacturing equipment must be reliable and accurate enough to reproduce exact chemical doses and process times, but flexible enough to permit technicians to make changes when needed. An intuitive operator interface, transparent programming of process steps, and easy adaptation of variables to new requirements help achieve excellent results. Software controls that deliver reliable reproduction of existing processes along with flexible programming for responding to changing requirements can significantly improve facility output.

Software Must Combine Support for Current Operations and Meet Future Needs

Modutek’s software can set process parameters such as chemical dosage, wafer etching, and cleaning times as well as other process parameters. Touch screens with a Graphic User Interface (GUI) allow operators to see process status and intervene if necessary. The displayed process shows the information on the status of the processing equipment. In addition, all set points can be easily modified to reflect your requirements. The software Modutek provides combines operational reliability with the flexibility needed to adapt the programs to new situations or requirements.

Optional Equipment Interface Makes Sure Commands Are Executed Correctly

Modutek offers SECS/GEM protocol or Ethernet access for the data logging interface. This interface allows Modutek to make output changes and integrate new wafer manufacturing equipment while ensuring that software commands are executed properly and accurately. Operators can read displays of process characteristics on the GUI to ensure command execution takes place as expected. All these options are reviewed during the station design layout process to ensure it meets your process and budget requirements.

Peripheral Control Features Can Enhance Software Performance

Data logging can improve performance by providing operators with additional information that allows them to optimize operations. Data loggers can track indicators such as output, process temp, processing times, and all alarm features. All data can form the basis for an evaluation of facility performance and plans for targeted changes to reach clearly defined goals.

Modutek can integrate standard or custom peripheral control features as needed by customers for specific applications. Customers may require certain information to optimize their process or depend on output data for subsequent action. Modutek can analyze such requirements and add the necessary functionality, both in terms of sensors or additional equipment and to ensure the information is processed and presented in a useful format.

Designing and Building Advanced Software Controls to Improve Silicon Wafer Processing

As a leading wet bench manufacturer with extensive experience and expertise in designing and building equipment in-house, Modutek works with customers to ensure their software controls meet their needs. In addition to providing excellent customer support, Modutek can evaluate complex customer applications to propose the best possible solutions. Contact Modutek for a free consultation to discuss your manufacturing equipment needs.