Advantages of Using the KOH Etching Process

Advantages of Using the KOH Etching Process for Silicon EtchingThe KOH etching process uses a potassium hydroxide solution to etch silicon wafers and produce microscopic structures in the silicon. In subsequent semiconductor fabrication steps, the micro structures are used in the manufacture of integrated circuits, processors and other electronic devices.

Compared to other etching processes KOH etching is comparatively safe, etches silicon rapidly and can be tightly controlled. These characteristics are especially important for batch processing when a process step has to be reproduced precisely many times. While other chemical processes are required for specific semiconductor cleaning and etching steps, industrial plants and research facilities prefer the KOH process for general silicon etching.

How the KOH Etching Process Works

The KOH solution is prepared by adding KOH to water in an etching tank made of material impervious to aggressive chemicals. Silicon wafers are masked with silicon nitride or silicon dioxide, substances that the KOH solution does not etch. When the wafers are immersed in the KOH solution, silicon is removed from the areas that are not masked by the chemical action of the KOH etching solution.

The etch rate can be controlled by changing the concentration of the solution and by changing the temperature. The concentration is fixed once the process is established and is usually around a 30% solution by weight, but may be as low as 10% and as high as 50%. Typically the solution temperature is about 60 to 80 degrees centigrade and the etch rate increase is very sensitive to an increase in temperature.

Other factors influencing the etch rate are the crystal lattice planes of the silicon and the presence of boron doping. Different crystal lattice orientations are etched at different rates so that the crystal lattice planes influence the design of the masks and their placement. Boron doping can be used to stop the etching in a specific direction. Taken together, all the ways the etch rate can be controlled allow the creation of complex shapes in the silicon.

Controlling KOH Etching

Obtaining the desired etching results from the KOH process can be divided into two groups of control measures. The concentration, doping and lattice orientation are determined initially before the process starts and establishes itself. At that point, temperature control can still change the etching rate. The initial control measures can be put in place with the required precision, concentration and other characteristics but the temperature of the etching solution must be controlled accurately on a continuing basis.

Because the KOH etching process is very temperature sensitive, maintaining the temperature at the exact set point is important. The temperature controller must be accurate during the process and also from one batch to the next. Tight control during the etching process ensures that the etch rate remains constant while precisely keeping the same temperature for a given set point from one batch to the next ensures accurate reproducibility of process conditions and identical output across different batches.

Modutek’s Teflon Silicon Etch Tanks

Using Modutek’s Teflon tanks allows operators to fully benefit from the advantages of KOH etching. The tanks are designed with KOH etching in mind and feature a wide temperature range, tight temperature control and rapid heating. Custom sizes are available and custom installations can be designed to fit any new or existing wet bench application.

Heating in the Modutek Teflon tanks is either in line or through an immersion heater in the overflow weir. Temperatures can be controlled to plus/minus 0.5 degrees centigrade and the temperature range is 30 to 100 degrees centigrade. The heating rate is 2 to 3 degrees per minute, depending on the size of the system, and heating is even throughout the bath. Since temperature control is a key requirement for successful KOH etching, these system characteristics allow for excellent reproducibility between batches and for the precise control needed for high quality output.

Apart from excellent temperature controls, the Modutek Teflon tanks feature all TFA Teflon with advanced manufacturing techniques designed to minimize contamination. Options such as an auto lid feature or a condensing refluxor are available if needed. Modutek Teflon tanks are an ideal solution for KOH etching applications and the company can help select the model and options that best satisfy specific customer needs. Contact Modutek for a free consultation on selecting the right equipment for specific process requirements.

Why Chemical Lift Station Pumps Are Needed for Wet Bench Stations

why-chemical-lift-station-pumps-are-needed-for-wet-bench-stations2Once a wet bench process step is completed, the remaining chemicals and waste water have to be drained and transferred to an area for neutralization and disposal. Depending on the physical layout of the semiconductor manufacturing facility, gravity draining may either not be possible at all or may be insufficient in terms of flow and speed. Chemical lift station pumps take over the transfer of chemical solvent in a controlled and optimized way. The removal of chemical solvents and waste liquids is accomplished rapidly and completely, leaving the wet bench station ready for a new process step.

Lift Station Pumps for New Installations

While it may be possible to design new installations without lift station pumps and relying only on gravity drains, changes in the facility, expansions or upgrades may require the retrofitting of pumps. In that case, lift station pumps have to be included in separate stations that are often located behind the wet bench stations. These separate stations take up valuable floor space that could otherwise be dedicated to productive process elements. As a result, incorporating lift station pumps in new wet benches is more desirable.

Modutek can add lift station pumps to their wet bench stations and use them to pump acids, solvents and related chemicals and solutions in their semiconductor manufacturing equipment. The lift stations automatically monitor the lift station tanks. When fluids are detected in the tank via the installed level sensors, 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.

Adding Lift Stations to Existing Processing Lines

When wet bench processing lines are used with a new process or are upgraded, the gravity drains that were previously adequate may no longer deliver the required flow. Lift stations have to be added to deliver the anticipated performance. Often extensive customization of the lift stations is required to accommodate them in the existing facility.

Modutek can help find solutions to adding chemical lift stations to wet processing lines. The company has a complete line of chemical lift stations for installation outside existing wet processing stations. Modutek engineers evaluate process requirements and plant layout to propose equipment that works best for a particular application.

Modutek’s chemical lift stations have all-plastic fluid paths for resistance to corrosion and feature an automatic constant ON with level sensing governing operation. Standard pumps are vertical centrifugal polypro with other pump options and a double containment option available. The polypro holding tank can be built to the size required and the designs are customized to meet flow requirements. Level sensing is via four float-type level sensors signaling low/low, low, high and high/high. Remote control is available.

Modutek Delivers Customization and Support

Modutek can analyze the requirements of a wet bench installation and propose ideal solutions because the company designs and builds their wet bench equipment in house at their facility in San Jose. With almost 40 years experience in wet bench technology, Modutek has the expertise to find optimum solutions and implement them using their own equipment. Chemical lift stations for existing installations and lift station pumps incorporated into new wet bench stations often require extensive customization. Such customization can include different geometry, size, materials, and control logic to meet unique customer requirements. Modutek can rely on in house experience to adapt its equipment for a specific application. Once delivered and installed, Modutek can provide unparalleled customer support because the company doesn’t use third party suppliers. The Modutek specialists carrying out wet bench and lift station service are backed up by the Modutek personnel who designed and built the equipment.

Why Preventative Maintenance of Wet Bench Equipment is Important

Why Preventative Maintenance of Wet Bench Equipment is ImportantTimely preventive maintenance of wet bench equipment allows semiconductor manufacturers to avoid costly unexpected downtime due to equipment failure and quality issues. Wet bench equipment is complex and is typically used in a demanding manufacturing environment. Calibration, cleaning and replacement of parts that wear out has to be performed regularly to maintain facility performance and output quality. Once scheduled, preventive maintenance has to be carried out quickly and professionally, completing the required tasks on time and using personnel with the required expertise. If the necessary preventive maintenance is not completed or is not done correctly, poor quality products, equipment damage and compromised worker safety can result.

Scheduling Preventive Maintenance

Wet bench stations operate with corrosive chemicals while at the same time relying on the highest standards of cleanliness and control of contamination. Chemical dosages and control of variables such as temperature are critical for a successful production line. Some components have to be changed, cleaned or serviced regularly while others have to be inspected to see if any action is required.

The semiconductor manufacturing equipment supplier will often specify what preventive maintenance measures are required and which ones are recommended. Some tasks can be carried out by the semiconductor manufacturer’s personnel, but others will often require specialists from the supplier. Developing an overall schedule that limits downtime for the production line to a minimum while ensuring that all preventive maintenance tasks are scheduled and carried out can be challenging.

Carrying Out Preventive Maintenance

Depending on the details of the semiconductor manufacturing operation, some preventive maintenance tasks can be performed while the line is in operation. For some lines, production steps are sequential so that a particular piece of equipment may be at rest for a given period. Preventive maintenance can then be carried out on that equipment.

Other parts of the production line may be in more or less continuous use for periods exceeding the recommended preventive maintenance interval. In such cases the required downtime has to be factored into the production schedule with reduced throughput. When all these factors are taken into account, it becomes clear that preventive maintenance for wet bench equipment may have to be flexible and reactive to manufacturing requirements rather than based on a fixed schedule.

Coordinating with a Competent Supplier

Developing an ongoing wet bench preventive maintenance program is easiest when partnering with a supplier who is familiar with the installation and who can handle all preventive maintenance tasks, even if the stations are highly customized. Such a supplier can help the semiconductor manufacturer develop and adapt a suitable schedule and help complete the work. The supplier can offer to carry out those tasks that specialists can perform quickly and competently while giving instructions for on-site semiconductor manufacturing personnel to complete simple tasks and inspections. Such an approach is ideal from the facility owner’s point of view.

Modutek can offer this type of field service and customer support because it has in house expertise based on almost 40 years of experience in the wet processing technology field. Scheduling and carrying out preventive maintenance on wet bench stations while keeping disruptions to production at a minimum requires such experienced personnel.

In addition to highly qualified specialists, Modutek designs and builds all its own wet bench stations at its manufacturing facility in San Jose. As a result, it can offer first-hand service, repair, and upgrade support without having to call on third parties. Working with a competent partner such as Modutek helps customers carry out the necessary preventive maintenance that keeps their equipment functioning at an optimum level while reducing downtime and avoiding compromised product quality.

How the IPA Vapor Dryer Improves Wafer Processing Results

how-the-ipa-vapor-dryer-improves-wafer-processing-results

Not every advancement in semiconductor fabrication produces results that are usable in industry. To be of value, advancements need to be consistently repeatable when used on an industrial scale. Modutek’s IPA vapor dryer falls into this category, helping semiconductor fabricators improve both yields and processing times.

Modutek’s IPA vapor dryers are custom-engineered with in-house experts working in partnership with a client’s technical staff. From a thorough understanding of a client’s manufacturing process, Modutek works to make sure their equipment is designed and tested to meet the requirements.

The Marangoni IPA Vapor Dryer Design

Silicon wafers require cleaning, rinsing and drying at certain stages of the fabrication process. The results need to be as close to perfection as possible, with no watermarks, and minimal particle contamination. In the past, these results were obtained through rapid spinning and heat drying. These simple methods no longer work with the latest high-density wafers, however. Not only is water hard to remove from complex shapes, drying without leaving watermarks is impossible.

Contamination from incorrect cleaning and drying can cause serious product malfunction and high failure rates. This is where drying by isopropyl alcohol comes into play. IPA drying by the vapor method, delivers wafers that are completely free of watermarks and with minimal contamination. Modutek’s IPA vapor drying system is both cost-effective, and ready for seamless integration into the standard wet bench process or free-standing design.

How the IPA Vapor Dryer Design Works

Modutek’s IPA vapor dryer design is unique in a number of ways. This design delivers high-quality results through serving IPA vapor at the upper reaches of the drying tank. This makes sure that vapor distribution is even. Since the surface tension of isopropyl alcohol is lower than that of water, such vapor serving introduces a gradient of surface tension where isopropyl alcohol meets with a layer of water on the wafer surface. With this type of drying effect, water quickly leaves the wafer surface, and leaves it completely dry and clean. Since the water does not actually evaporate, it leaves the watermarks behind. The drying process takes no longer than 15 minutes.

The Advantages of Modutek’s IPA Vapor Dryer

Modutek’s in house experts in IPA vapor dryer design work together with a clients’ technical team to design and create IPA dryers that specifically meet their application requirements. Clients are able to come to Modutek’s facility for testing to make sure that their equipment works as expected.

With extensive experience in the wafer processing industry, Modutek is fully able to provide top-notch equipment and customer support at every stage of the design process, during delivery and after the sale. With expertise in semiconductor processing equipment, Modutek is able to address every specific client need for this industry. Contact Modutek for free consultation on the equipment needed for your specific wafer manufacturing process.

 

 

 

How to Qualify Which Semiconductor Equipment Manufacturers Meet Your Requirements

how-to-qualify-which-semiconductor-equipment-manufacturers-meet-your-requirementsThere are a number of things to keep in mind when you review which supplier to use from a list of semiconductor equipment manufacturers. From the ability of a manufacturer to customize solutions to meet specific client needs, to company reputation, the quality of the equipment sold, and after-sales support, there is a lot to consider. Only after you create a shortlist of potential companies to work with should you consider pricing and other minor details.

The Customization Question

Whether the need is to upgrade lines or replace old equipment with new machines, every semiconductor foundry or research facility is different, and comes with very specific requirements. Often, equipment newly purchased needs to be able to interface with systems already in place, and at other times, space or system size concerns override all other areas of consideration.

Equipment may also need to be internally customized with specific feature additions in order to be able to deliver on client requirements. Equipment manufacturers need to provide extensive experience and expertise with such customizations. Before a specific semiconductor equipment manufacturer can be chosen, they need to be able to demonstrate that they are able to work with clients, and to supply systems that are customized to their needs.

Reliability of Equipment

Once equipment has been purchased and set up, it needs to stay online for long stretches of time with minimal downtime. The best way to determine if a manufacturer is able to supply equipment of such description, is to contact references and study reliability statistics. Suppliers should be asked to furnish detailed information on scheduled downtime requirements, and logbooks obtained from actual installations.

After-Sales Support

Equipment warranties and support capabilities are the last item on the list to look at before a contract is signed with a selected supplier. Warranty policies should be simple and straightforward, and yet be comprehensive in describing what’s covered. All new equipment should typically come with at least a one year warranty.

It’s also important to check on the strength of every company’s service department. The most generous warranty policy would not be of much use if there were few personnel able to deliver on it. If there are third-party service providers that are on call, rather than an in-house department, it might be a warning sign that the manufacturer is not well-equipped to deliver a quality after-sales experience. Since third-party service providers usually deal with products from multiple companies, they are not likely to be as expert in their fields as in-house personnel. The best way in which to check on a company’s service ability is to simply call with a question prior to purchase.

Use a Supplier with a Proven Track Record

Finding the right equipment supplier is a vital step in the set-up of a semiconductor manufacturing facility or research center. The equipment from a supplier will affect future productivity, and quality of output. Since many suppliers have come and gone over the years look for one that has a proven track record that has been around for awhile. In addition the systems and equipment they sell should be continually improved to keep up with the latest technology and allow for easy upgrades.

Modutek’s Experience, Expertise and Longevity

Modutek has over 35 years of experience as a semiconductor equipment manufacturer, and has continually operated during that time to improve their equipment and address the needs of many clients. Not only does Modutek design and assemble their own equipment, all their software is designed in-house as well. They provide expert support through its own employees, rather than though agreements with third parties. In addition Modutek is committed to complete customer satisfaction, and has a record that shows it. Contact Modutek for a free quote or consultation to discuss your specific semiconductor manufacturing equipment requirements.

 

How New Equipment Has Improved the Silicon Nitride Wet Etching Process

how-new-equipment-has-improved-the-silicon-nitride-wet-etching-processThe silicon nitride wet etching process is difficult to control safely but is a key component of semiconductor wafer manufacturing. The process uses phosphoric acid to remove silicon nitride masks from silicon wafers to allow the clean wafers to undergo further fabrication steps. The hot phosphoric acid and water mixture is unstable and requires periodic addition of small quantities of water, but adding water to phosphoric acid may produce a bump. Modutek has developed a new approach to control the nitride etching process safely and accurately while achieving high etching rates.

How the Silicon Nitride Wet Etching Process Works

The etching of silicon nitride masks with phosphoric acid is optimized at a temperature of 160 degrees centigrade for a mixture of 85 percent acid and 15 percent deionized water. At this temperature, the mixture boils and some water is lost as steam. The lost water has to periodically be replaced, but adding water to phosphoric acid can be dangerous. The water may not immediately mix with the acid, instead forming a film on top of the mixture. If the film suddenly mixes with the acid, introducing a large amount of water into the mixture at once, a bump can result.

In order to optimize etching performance small amounts of water are added periodically which immediately mix with the acid to maintain the temperature at the ideal 160 degrees centigrade. If too much water is added, the temperature of the mixture may drop and the mixture may stop boiling, allowing the water film to form and create a dangerous situation. If too little water is added, the temperature of the mixture will increase and even more water will be lost. Modutek has new equipment provides an innovative control strategy that addresses these issues and delivers excellent etching performance.

Modutek’s Nb Series Silicon Nitride Wet Etching Bath

Modutek’s new Nb series bath provides tight control of the bath temperature while ensuring a safe operation and superior etching of the silicon nitride masks. In addition to the new control strategy, the series Nb baths offer additional safety features that make sure the dangerous condition in which large amounts of water are mixed with hot phosphoric acid is avoided.

In their new silicon nitride wet etching equipment, Modutek uses the acid mixture concentration as a reference value for adding small amounts of deionized water. At normal operation, the bath heater is on and the mixture is always boiling at the normal mixture boiling point of 160 degrees centigrade.

The boiling point of the mixture varies with the concentration. As water is lost and the mixture concentration rises, the boiling point increases as well and the mixture temperature starts to rise above 160 degrees centigrade. This rise triggers the addition of a small amount of deionized water. Since the mixture is always boiling because the heater is always on, the deionized water is immediately mixed in with the boiling acid, the concentration of the acid is reduced and the mixture boiling point decreases back down to 160 degrees centigrade.

To guard against the addition of water when the mixture is not boiling, a thermocouple sensor above the boiling mixture detects the presence of steam and closes the water valve when no steam is present. This additional safety feature ensures that a dangerous water film cannot form even under abnormal conditions such as heather failure.

Modutek has been testing and fine tuning the new system with Nb silicon nitride wet etching baths to customers in manual, semi automated and fully automated wet bench stations. Semiconductor fabrication facilities and research centers using the new equipment have achieved an average etch rate of 65 angstroms per minute while limiting oxide etch as the controls ensure safe operation at a consistent and optimum operating point.

 

 

How to Safely Use Solvents for Wafer Processing

how-to-safely-use-solvents-for-wafer-processingAt semiconductor research centers and foundries, solvent wet bench stations provide a critical role in the semiconductor fabrication process. These stations are designed for operations that include substrate cleaning, photoresist stripping and liftoff pattern transfers. Since the solvents are often highly inflammable, wet bench equipment needs to be designed with stringent compliance to safety codes.

Equipping for safety

Precautions related to fire safety and electrical safety is among the most basic requirements in wet bench station design. Fire suppression can involve the application of spark-resistant electrical design all around, and the provision of extinguisher equipment. Solvent wet bench stations must be designed to meet Class 1 Div 2 certifications, and incorporate a carbon dioxide (CO2) fire system.

Safety alarms: Exhaust, CTA and N2 safety interlocks should monitor for use within acceptable ranges. Safety doors on the head case and elsewhere should be monitored during use and should be able to shut down operation if they are opened during use. Float switches should detect liquid spills on the floor of the bench. Differences in pressure between the exhaust on the bench and the rest of the room should be monitored through the use of photohelic gauges (low readings indicating incorrect operation should sound an alarm).

Carboy collection: Since solvent waste should never be sent down the drain, carboys help collect waste for containment. Multiple containment volume sizes are available.  All come with current safety interface.

Heated solvent baths: Temperature control is achieved in many ways, and heated baths are one of them. They should be used to control the temperature of the solvents being used. Temperature controllers should be used both to raise and lower temperatures and to monitor temperatures.

Process timers: These vital pieces of equipment should be mounted to the head case to ensure that personnel are able to keep track of how long each process is to run.

Restrictions on use: A login system should ensure that only authorized individuals are able to access the bench.

In many cases, safety comes from simpler approaches — the use of auto lids made of Teflon or stainless steel to help seal off chemical containers.

Modutek’s Solvent Wet Bench Equipment

Available in manual, dry-to-dry, semi-and fully-automated designs, Modutek’s stainless steel solvent stations are constructed all through using 304 stainless steel. Solvent applications require the use of this material. From photoresist to IPA, and acetone, these stations are suitable for critical operations in the wafer processing activities. From solid works simulation to professional flow simulation, many critical flow characteristics are available. Improvements to productivity are achieved through the use of Modutek’s advanced software.

Modutek’s safety design for solvent processing involves every required feature. With wiring specified to NFPA 70 & 79 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, and continuous flow of the water manifolds, Modutek’s designs are among the safest of all wet stations.

With a chemical management interface, a PCL with touchscreen GUI, a rear access design, Teflon plumbing throughout, certification to the CE Mark, and seismic certification, Modutek’s equipment incorporates features beyond legally required safety measures.

Modutek’s Wet Bench Design and Build Process

Wet bench construction is a complicated process, and Modutek provides systems that are designed to meet the requirements of specific applications of individual customers. With 35 years in the business, Modutek understands that acid and solvent processing for micro fabrication requires customized solutions. Modutek’s designs and builds all their wet bench stations in house to ensure every part of the system provides reliable performance. If you need a solvent wet bench station designed and built to meet your requirement s contact Modutek for a free consultation or quote.

 

Improving Wafer Processing with Automated Equipment

Fully and semi-automated wafer processing equipment can help improve wafer output quality by providing consistent chemical processing dosages and timing, however these settings must be first be determined. One way to find optimal process settings is to operate in manual and then in semi-automated mode where settings can easily be adjusted. This is especially true of new process development where the exact parameters are not known. Wafer fabrication facilities can first try out initial settings in manual mode and tweak or “fine tune” them to obtain the desired output. Using semi-automated stations to run the parts of the process that are finalized while making additional adjustments gives optimal results. These can then be made permanent in a fully automatic station.

Steps for Improving the Fabrication Process

Although the overall process is known and the chemicals to be used are set, a new fabrication process may initially not work as desired. Perhaps the etching is not at the expected speed, or the results are not consistently reliable. While the effects of changing chemical concentrations and timing for bath exposure are known, the optimum variables for the specific process have to be found.

After an initial run, the problem areas can be identified and variables such as chemical dosages and timing can be adjusted. Skilled and experienced operators can carry out the fabrication steps and make changes easily on a manual station. In manual mode, the operator is completely in control and nothing happens unless the operator initiates the action. Such control can be important when determining initial settings for a new process.

Once the major parts of the new process work as expected, there may still be minor adjustments necessary to achieve targets such as faster processing, better quality output or reduced chemical use. For such adjustments, use of a semi-automated station saves time. Instead of carrying out all the steps manually, the semi-automated station can run the parts of the process that don’t need adjusting. These parts will run reliably without operator intervention, as programmed and without deviation from the correct set points. The operator can then focus on the final adjustments to optimize and then utilize fully automated wafer process equipment

Subsequent Tailor Made Full Automation

Once the parameters and variables for the desired yield and performance have been determined, a tailor-made software and automation package can be assembled. This package, in a fully automated station, reproduces the custom settings of the manual and semi-automated process steps and uses them to consistently produce the desired results. Carrying out the fine tuning of the process on manual and semi-automated stations first allows the fully automated station with the optimized settings to scale up to full production right away. The tailor-made solution for a specific new process can immediately produce the desired yields and process characteristics.

For semiconductor fabrication facilities that often bring online new processes, using manual and semi-automated stations to fine tune the process and develop a tailor-made solution can be an attractive alternative to optimization on a fully automated station. Full automation is still desirable for production runs because of the greater reliability, accuracy and reproducibility that such stations deliver. Once the optimized software and automation package is running production on a fully automated station, the station will produce consistently high-quality output, high yields, low defect rates and use chemicals efficiently.

Modutek can work closely with each customer to determine the best way of optimizing new processes. The company’s full line of wafer processing equipment including manual, semi-automated and fully automated wet bench stations lends itself to this kind of optimization to produce ideal outcomes. Wafer fabrication facilities that consistently optimize new processes can lower overall costs and improve facility performance. Contact Modutek for a free quote or consultation on selecting the right equipment to support your manufacturing process requirements.

 

How Acid Fume Scrubbers Work to Maintain a Clean Work Environment

Creating silicon wafer microstructures, integrated circuits, and processors requires an extensive multi-step process of etching, stripping, and cleaning silicon wafers. Chemicals such as sulfuric acid, hydrochloric acid or hydrogen peroxide carry out these operations effectively but give off vapor that is harmful for workers inside the workspace and for the environment outside. In addition to affecting worker health, there are regulatory compliance issues for a safe working environment. Acid fume scrubbers remove the harmful vapors from the air, leaving a clean workspace and clean air to be discharged outside the manufacturing facility. Modutek’s acid fumes scrubbers are especially effective and have a low cost of operation as well.

Acid Fume Scrubber Operation

The exhaust air from wet process stations will often contain droplets of the acid used in the process. Even as a mist of fine droplets, these acids remain extremely corrosive and may impact worker health, especially if inhaled. With increasingly strict regulations regarding worker safety and environmental impacts, such exhaust air has to be treated before being released into the workspace or outside.

Acid fume scrubbers neutralize the acid vapors and clean the exhaust air so that it is no longer dangerous for workers or harmful to the environment. The exhaust air containing the acid fumes is passed over a bed of wet packing material. The liquid in the packing material bed includes a chemical that neutralizes the acid safely. The acid droplets dissolve in the neutralizing liquid as the vapor passes over the wet packing bed and the acid is neutralized as it is absorbed from the exhaust air. The air exiting the acid fume scrubber contains only traces of acid and is safe.

The effectiveness of the scrubbers depends on the volume of air the scrubbers can handle and the surface area of the wet packing that is exposed to the acid fumes. Modutek’s acid fume scrubbers use packing material from packing technology leader Lantec to achieve an especially high surface area in the packing bed. To match the air exhaust requirements, Modutek acid fume scrubbers are available with air handling capacities from 500 to 25,000 CFM. Matching the air handling capacity to the high packing material surface area can result in acid fume removal from the exhaust air of up to 99 percent. At the same time, a water re-circulating system with pH control keeps the water consumption to a minimum and operating costs are low. Installing Modutek acid fume scrubbers lets wafer fabrication facility managers keep their workspaces clean and operating environment safe.

The Benefits of Using Acid Fume Scrubbers

When acid fumes get into the workplace, it impacts the workers and can corrode machinery. Even small concentrations can have negative effects over time. A clean work environment is especially important in semiconductor wafer fabrication because contaminants on the wafers affect the quality of the final product. As a result, placing acid fume scrubbers in the air exhausts of wet stations can improve worker health and improve product quality.

Modutek’s high efficiency acid fume scrubbers are complemented by a safe operating environment and an operator-friendly user interface. Double containment construction adds extra safety and there is a bottom drain for easy maintenance. The flow and pressure gauges give the operator a complete picture of the process while level control and metered discharge help ensure proper operation. With the neutralization of the acid taking place within the scrubber, operation of the scrubber is completely safe.

When the work environment is clean, workers will perform better, especially if they know they don’t have to be concerned about their health. Modutek’s acid fume scrubbers ensure that a clean and healthy work environment is possible, even in the face of using chemicals common in wet process wafer fabrication facilities. Contact Modutek for a free quote or consultation on selecting the right fume scrubber for your facility.

 

How Customized Equipment Has Improved the Silicon Wafer Cleaning Process

Different customized systems or custom components may improve silicon wafer cleaning processes because customers have special requirements or because the process characteristics are unusual. Suppliers taking on such projects must have extensive in-house experience and expertise together with a board line of silicon wafer cleaning equipment to provide custom solutions. When customization is required, effective solutions can improve throughput, lower costs, and result in higher output quality and yield. Modutek has both the experience and in-house expertise required to offer such customized equipment.

Customized Software

Modutek’s SolidWorks Simulation Professional and SolidWorks Flow Simulation software allows customers to calculate chemical doses accurately as well as track chemical usage. Such calculations are especially important for custom installations because the inputs and the values obtained may be non-standard. Modutek develops and writes all its own software so the company can make adjustments and implement software customization whenever it’s required by a customer. This means that customers can rely on software that corresponds to their customized systems rather than trying to operate a custom system with standard software. Modutek’s software can tailored to precisely control and monitor even the most customized installations.

Custom-Fit Equipment

A lot of the equipment that goes into a silicon wafer cleaning installation has to fit into an existing space or fit other limiting installation parameters. Such custom-fit equipment may include:

  • Megasonic systems
  • Teflon tanks
  • Quartz baths
  • or other custom equipment

Modutek can build custom versions of these components to fit any existing or new wet process system to optimize the silicon wafer cleaning process. Megasonic cleaning systems can be customized for frequency and power while tanks can be sized according to custom requirements and can be fitted with heaters or re-circulating pumps as required. In each case, Modutek can analyze the silicon wafer cleaning application and recommend the most appropriate solution.

Custom Wet Bench Station Design

When preparing a custom wet bench station design, Modutek first looks at the process specifications. The software, chemical delivery systems, baths and wafer handling must all fit together to satisfy the process requirements. Sometimes customized components can be used in a standard configuration but at other times specially designed components may be arranged in a custom system.

This approach provides end-user flexibility while respecting customer specifications and ensuring that the equipment performs as expected. All systems are designed and built at Modutek’s company facilities based on their own in-house expertise and experience.

Customized Wet Process Systems

Wet process systems can be customized at the component or system level, but they can also feature customized levels of automation. Standard systems are manual, semi-automatic or fully automatic but special solutions are always possible. Customers may want a manual system but also want certain process sub-steps to run automatically. A customer may want the handling of hazardous chemicals to be fully automated for safety reasons but want the rest of the process to be manual. On the other hand, a fully automatic system may have a requirement for operator intervention at a specific point. Because Modutek designs these systems in-house, such customization is seamless and problem-free.

Customized wet process systems can find application in many research and industrial fields. A customized system is often needed for prototype development and testing since the prototype can have unusual or unique features. Cutting-edge research and development in industry or at universities may also require the special characteristics available from customized systems. Even full production manufacturing facilities may need customization if they want to try special cost-cutting or quality-enhancing production methods. In each case Modutek can analyze the requirements and propose solutions.

With over 35 years of experience in wet process technology, Modutek has pioneered customization as a tool for improving silicon wafer cleaning processes and continues to develop unique customized solutions for its customers. If you need a customized solution for your application contact Modutek for a free consultation or quote.