How Software Controls Support Unique Wet Processing Requirements

 5 Important Things to Know When Buying Wet Bench StationsAutomated software control systems can help improve wet bench operations but the software has to be flexible to meet the unique needs of a wet processing application. Software controls increase dosage accuracy, timing reliability and process safety but process parameters or even the process itself can change as regulations tighten, customer requirements change and suppliers differ. The ideal automated process station is custom built to exactly match the requirements of a particular process while retaining the software programming capability to respond to production line changes.

User Interface

Modutek’s fully automated wafer fabrication equipment features touch screens with a graphical user interface (GUI). Operators can see the status of the manufacturing process and can start and stop steps if required. Because Modutek designs and programs its software in house, the company can respond to unique requirements at the software level and can add equipment to the GUI if the process changes.

Equipment Interface

Once the operator starts a process and the software program runs, the automated system has to output commands to the equipment on the production line. Modutek uses the SECS/GEM interface standard, which stands for SEMI Equipment Communications Standard/Generic Equipment Model.

SEMI is the Semiconductor Equipment and Materials International organization that developed the standard and defines the communication forms and messaging underlying the interaction of the software and the semiconductor manufacturing equipment. Using a common standard lets Modutek integrate other equipment into its production line designs and easily make changes to the software.

Automated Controllers

Controllers convert the input commands from the operators to corresponding output commands in the correct sequence to control process variables and the motion of the robotics. The sequence of commands is programmed into controllers such as PLC (programmable logic controllers) units that activate a command chain when the right input command is given. PLCs have the advantage that the programmable chains are easily re-programmed to meet changed requirements or equipment changes on the production line.

Because they design their own automation systems, Modutek can integrate higher level controllers such as Omron machine automation controllers or controllers from specific manufacturers such as Allen Bradley. Special controllers are often needed for unique functionality or for integration with existing systems.

Flow Simulation Software

Modutek’s SolidWorks Simulation Professional and SolidWorks Flow Simulation software is designed and programmed by the company’s software engineers to calculate chemical dosages and track chemical usage. The software ensures that the process environment for a particular batch is always the same, producing reliable etch rates and consistent throughput. When the process changes, the software can calculate new parameters and can automatically supply the right amounts of chemicals.

Vision Sensing

Fully automated wafer fabrication equipment can benefit from vision sensing with cameras and other optical sensors. The detected images have to be processed to identify the characteristics required by the system. Vision sensing can help with measurement, wafer or die alignment, quality inspection, sorting and mounting. For example, a coating could be inspected for continuity or products could be sorted according to defined properties. Modutek can integrate vision sensing into its fully automated wet process stations and help make sure the required functions work as desired.

Data Logging

The automated system can be programmed to output process variables to data logs that allow tracking chemical use, product quality, output and similar variables. The software sends the required data over Ethernet to create reports that operators and management can use for evaluating production line performance.

Modutek Designs Advanced Software Controls for Custom Applications

In 2020, Modutek is marking their 40th year of operation as a semiconductor equipment manufacturer and wet processing equipment supplier. The company’s success is due to innovation and continuous improvement in equipment and software to benefit their expanding customer base. For any wafer processing equipment needs contact Modutek for a free consultation or quote.

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

 5 Important Things to Know When Buying Wet Bench StationsCustom wafer cassettes made of specified materials or with specific physical characteristics are often needed in wet bench equipment for some applications. Research labs and universities may create unique semiconductor prototypes and start-ups may need sample semiconductors for testing. In each case, off-the-shelf carriers with the required characteristics are often not available. Custom wafer cassettes ordered in low volumes can meet the requirements of research and testing facilities and allow them to carry out the specialized silicon wafer fabrication they need.

Custom Wafer Cassettes are Needed for Research Applications

Research labs may need wafer carriers with unusual characteristics because they are testing new processes or using new materials. Universities may be trying to re-create a historical process or develop a new process that requires cassettes not commercially available. These organizations often need only a few of the custom cassettes to carry out their research and testing. The availability of custom wafer cassettes without a minimum order quantity is a key factor in the ability of the labs to carry out their research and testing.

Start-Ups Need Special Cassettes to Create Prototypes

When a start-up develops an innovative semiconductor product, off-the-shelf wafer cassettes may not be suitable because the product is not currently being produced commercially. The new product may require special processing and the wafer carriers used may have to use an innovative design or material as well. To produce different prototypes and test them in real-life situations, start-ups may need a series of custom wafer cassettes before they begin commercial production of their new product.

Up-graded Production Lines May Require Custom Cassettes

Modified production lines mean that some equipment has to be changed and other equipment adapted. Such modifications can take place as a result of changes in suppliers, updated regulatory requirements or new customer demands. Often parts of the production line are replaced or additional equipment is retrofitted. Large items such as tanks and baths may be kept but re-purposed. If wafer cassette operation is affected, new off-the-shelf cassettes may not be suitable and custom wafer cassettes, adapted to the new processing line, may be the best solution.

Modutek Can Provide Custom Wafer Cassettes

Modutek is a leading manufacturer of wet bench equipment that has in-house expertise to analyze customer requirements and deliver custom installations of the highest quality. With extensive experience in all aspects of wet bench technology, Modutek can offer equipment from its standard line of wet bench stations but can also meet special requirements because all equipment is designed and built in house. Once the details of an application are clear, Modutek can build the components so they meet any special requirements.

When custom wafer cassettes are needed, Modutek can design and build custom units as needed. The company has the capability to design and build special configurations and to use specific materials such as PFA Teflon, PFTE Teflon, PVDF and Natural Polypro. Custom carriers can hold between one and twenty-five wafers per carrier and carrier design can be optimized for a specific use. To emphasize its commitment to meeting the special needs of customers, Modutek does not require a minimum order quantity for custom wafer cassettes.

Semiconductor manufacturing is always complicated and a degree of customization is often needed to fulfill the requirements of a specific process. As the business environment of a semiconductor manufacturing facility changes, production lines have to be modified and the changed equipment has to be customized to fit the new configurations. Modutek can help identify such custom requirements and provide the corresponding custom equipment. Custom wafer cassettes are one specific case where Modutek can supply special components that are not otherwise available. Contact Modutek for a free consultation or quote on equipment needed for your specific requirements.

Improvements to the SPM Process Provides Significant Results

 5 Important Things to Know When Buying Wet Bench StationsWet bench semiconductor manufacturing relies on the SPM wafer cleaning process to quickly strip photoresist and other residue from silicon wafers. Because the hydrogen peroxide in the sulfuric acid peroxide mixture is unstable, hydrogen peroxide continuously degrades into water and the degradation is accelerated if the mixture is heated to increase the strip rate. To keep the SPM process concentration stable, hydrogen peroxide has to be added, spiking the concentration back to its original level. After several hours of repeated spiking, the mixture has to be replaced.

While other semiconductor equipment manufacturers provide less efficient solutions, Modutek has developed a “bleed and feed” method that keeps the SPM hydrogen peroxide concentration steady. The company has now collected operational results from customers using the new method and a comparison with the traditional SPM process shows substantial savings from reduced use of acid and better operational results.

How Modutek’s “Bleed and Feed” Method Works

The Modutek “bleed and feed” method uses a two-tank configuration with a clean tank and a dirty tank. Periodically an amount of mixture is drained from the dirty tank and replaced with mixture from the clean tank. The clean tank receives an amount of sulfuric acid to replace the drained amount and both tanks receive enough hydrogen peroxide to bring the concentration up to the set level.

The method is PLC-controlled with the initial drain amount, the replacement amount, the hydrogen peroxide amounts and the “bleed and feed” frequency all programmable. The SPM process concentration is maintained and the strip rate remains unchanged, but the SPM mixture has a much longer life. The cost savings result from the SPM mixture not having to be changed frequently.

The “Bleed and Feed” Method Reduces the Consumption of Chemicals

Operational data from customers shows that the Modutek “bleed and feed” method substantially reduces the use of the SPM process chemicals. Data was collected from a semiconductor manufacturing facility using a 2 6-inch carrier bath size and operating on an eight-hour shift.

The use of sulfuric acid was reduced by 77% while the volume of chemicals disposed at the end of the process went down 75%. Acid neutralizer and acid re-agent use declined as well. The reduced cost of chemicals and the savings from lower disposal volumes were substantial.

“Bleed and Feed” Can Increase Throughput

The spiking with hydrogen peroxide of the traditional SPM wafer cleaning process means that mixture replacement causes frequent down times for drain and re-pour. Use of the Modutek “bleed and feed” method reduced system drains from three times per day to once per week on average. The once-per-week change is supported by a quick-drain feature that lets the change-over to a new mixture take place quickly. Overall throughput was increased.

Operational Advantages of “Bleed and Feed”

In addition to cost savings from reduced chemical use and higher product volumes from increased throughput, customers saw operational advantages from using Modutek’s “bleed and feed” method. The reduction in chemical handling lowered the possibility of spills and increased operator and employee safety. At the same time, strip rates and other SPM process characteristics were at least maintained at previous levels or improved.

Customers Can Immediately Take Advantage of “Bleed and Feed”

The Modutek “bleed and feed” method is especially attractive to facility managers, process engineers and researchers concerned about the environmental impact of high volumes of toxic chemicals. Modutek can deliver the new method as part of its standard wet bench stations or prepare a custom design for a specific application. Since Modutek designs and builds its own equipment, the company has the expertise to propose custom solutions for any SPM process applications and allow all their customers to benefit from the new “bleed and feed” method. Contact Modutek for a free consultation or quote on equipment that is designed to meet your specific manufacturing requirements.

How the IPA Vapor Dryer Provides Superior Wafer Processing

 5 Important Things to Know When Buying Wet Bench StationsAfter etching and rinsing, an IPA (isopropyl alcohol) vapor dryer can produce dry silicon wafers without watermarks and limited particle adders. In IPA drying, also known as Marangoni drying, the Marangoni effect relies on the low surface tension of IPA compared to water. When IPA vapor is introduced into the drying chamber, a surface tension gradient is established between the IPA and water on the surfaces of the silicon wafers. The surface tension gradient causes the water to flow off the wafers, leaving them clean and dry. The slow drain water feature also helps reduce particles contaminating the wafer surfaces. As a result, IPA vapor drying can be used to produce especially clean, wafers after a final etch and before the next semiconductor manufacturing step.

IPA Vapor Drying is Safe for Thin Silicon Wafers

IPA vapor dryers are especially suitable for drying thin, delicate silicon wafers. In other drying methods, the wafers are placed in a drying chamber and rotated or spun to remove the rinsing water, but handling and moving these wafers can result in damage. With the IPA vapor dryers, the Marangoni effect dries the wafers without moving them. Delicate wafers are not subjected to any stress and damage is minimized while drying performance is excellent.

IPA Vapor Dryers Improve Wafer Processing After HF Last Etching

As the final process in a silicon wafer fabrication step, the silicon oxide layer on the wafer has to be removed with hydrofluoric acid (HF) etching. The wafer is then rinsed with de-ionized water and dried before passing on to the next step in manufacturing the final semiconductor component. Providing a clean wafer with a low particle count is critical at this point because subsequent process steps are affected by the presence of contamination or particles. For high-density semiconductor components, a particle or film on the silicon wafer can prevent the correct etching of a structure or the deposit of a conductor. Because IPA vapor dryers remove water from the wafer surface and reduce particle counts with their Marangoni effect, IPA vapor dryers improve wafer processing results and ensure higher quality output.

Modutek Single Chamber Processing Delivers Further Improvements

At the end of a wet process wafer fabrication step, the wafers are etched with hydrofluoric acid in an etching chamber and then transferred to a dryer. The transfer exposes the wafers to particle contamination that can lead to elevated wafer surface particle counts, even after Marangoni drying. Modutek has eliminated this source of contamination by developing a method that allows etching and drying in a single chamber.

With the Modutek etching and drying station, hydrofluoric acid is injected into the chamber at a controlled ratio to etch the oxide layer down to the bare silicon. The wafers are then rinsed with de-ionized water to a set pH level. When the pH level is reached rinsing is complete and drying can begin.

IPA vapor is generated from a standard one-gallon bottle and introduced at the top of the drying chamber. The drying cycle takes about 10 to 15 minutes and the dry wafers are ready for their next fabrication step. The wafers are not moved during the whole etching, rinsing and drying process, reducing wafer breakage, especially for thin, delicate wafers. Since the wafers stay in the chamber from etching to drying, particle contamination is significantly reduced.

Modutek’s extensive experience in the semiconductor manufacturing industry allows it to support customers in integrating the new single chamber IPA vapor dryer in any new or existing wet processing equipment. Modutek designs and builds their own semiconductor manufacturing equipment and can therefore offer customized versions to meet the requirements of any application. The company’s staff work with a customer’s engineering team to make sure the equipment meets the customer’s process requirements. Contact Modutek for a free quote or consultation to discuss your manufacturing equipment requirements.

Specialized Wafer Etching for Critical Wet Processing Applications

 5 Important Things to Know When Buying Wet Bench StationsImproving the performance of critical wet process applications depends on selecting wet bench processes designed for the tasks at hand. Specialized equipment can support different etching and cleaning processes and can be used to make sure that the process selected can fulfill specific application requirements. Modutek’s wet process stations are specialized for the different processes but also guarantee safe and reliable operation.

Specific Tasks Require Specialized Processes

Depending on the etching or cleaning task to be carried out, specific wafer etching process characteristics are needed. The fabrication of solar cells has different requirements than the creation of microscopic structures for a processor. The major process characteristics that can impact wafer manufacturing include the following:

  • Low particle count
  • Etching speed
  • Selectivity
  • Precise control
  • Undercutting

Low particle counts are always desirable but can be critical for the smallest structures. A high particle count can result in high rates of rejection during final testing because the particles cause defects in tiny structures.

Etching speed is related to throughput. If the goal is to remove a substance as quickly as possible, high etching speed can be prioritized at the expense of other characteristics such as precision. Ideally the process speed is optimized so the process step doesn’t become a bottleneck.

For highly selective processes, the substrate material is not affected by the etchant while the material to be removed is etched rapidly. While selectivity is a basic characteristic of wet bench processing and is always important, some applications require especially high selectivity and the process has to be chosen accordingly.

Precise control becomes more and more critical as the dimensions of the micro-structures decrease and the packing of components becomes more dense. Since this tendency is a current trend in wafer manufacturing, control precision is becoming more important.

Undercutting compromises control precision but can be limited or eliminated with anisotropic etching by choosing the appropriate process and the orientation of the silicon crystal planes. When undercutting under the mask is not acceptable, anisotropic etching results in clean and sharp corners.

Choosing the right process to deliver the etching characteristics needed can have a high impact on wafer etching process line performance. Key performance indicators such as product rejection rates, throughput, down times and operating costs can vary greatly depending on the best match of process to application. An experienced equipment manufacturer can help customers choose the best solutions.

Modutek Provides Wet Process Solutions for Different Application Requirements

Modutek offers a complete line of wet process stations and can deliver solutions for general etching and cleaning as well as for specialized applications. Among the processes supported by Modutek equipment are the following:

  • Piranha etch
  • KOH process
  • Buffered Oxide Etch (BOE)
  • Ozone resist strip

Piranha etch cleans organic material from substrates and is often used to remove photoresist from silicon wafers. It cleans rapidly and does not etch the underlying silicon. Modutek can evaluate whether piranha etch is a good fit for an application.

KOH etching is characterized by good control and the possibility of use for anisotropic etching. The etch rate is controlled by changing the temperature of the KOH solution and Modutek offers baths with tight temperature control.

BOE is used primarily to etch silicon dioxide and silicon nitride. It features good control and does not undercut masks. Modutek supports BOE with its sub ambient filtered baths.

Ozone resist strip cleans organic residue while reducing the particle count. The powerful oxidizing action of the ozone combines with carbon in the organic compounds to leave wafers clean and free of particles. Modutek offers the ozone strip process as a chemical-free alternative to traditional strip methods.

With extensive experience in all areas of wet process wafer fabrication, Modutek can help choose the specialized process required for an application and deliver equipment of the highest quality. In supporting special applications as well as general etching and cleaning, Modutek ensures that it can meet all the wet process needs of its customers.

 

How Quartz Tanks Improve Wafer Manufacturing

 5 Important Things to Know When Buying Wet Bench StationsThe aggressive chemicals used in wet process wafer manufacturing have to be contained in process tanks that can resist etching and corrosion while remaining inert. Depending on the application, a process may require heating, filtration or the regular addition of chemicals. Quartz tanks from Modutek are made from semiconductor grade flame-polished quartz and are impervious to the acids and bases used in wafer processing. They minimize contamination of the wafers with particles and can be supplied in heated and re-circulating models. The high quality of the bath material along with advanced control strategies developed by Modutek help improve wafer manufacturing performance.

Cleaning Silicon Wafers Using Quartz Tanks

Wet bench processing of silicon wafers consists of fabrication steps such as etching and diffusion with cleaning required in between the steps. Wafers may be masked to etch specific parts of the wafer or to confine diffusion to certain target areas. After each process step is complete, the masking material has to be cleaned off.

Cleaning the wafers completely without contamination is critical because subsequent processing steps are affected if the wafer is not completely clean. With the microscopic architecture of semiconductor components becoming more tightly packed, even a single particle can result in a badly formed structure or conductor. When such malformations are incorporated into the final product, they can be the cause of defective or lower quality semiconductor components.

Specialized Process Controls Help Improve Wafer Manufacturing Results

Specialized quartz tanks from Modutek are based on over 30 years of experience and incorporate features to guarantee safe, reliable operation while delivering excellent wafer manufacturing results. Custom sizes, fast and even heating, reduced downtime and long vessel life help improve manufacturing facility performance and reduce costs. Quartz tank controls allow operators to program reproducible process environments and make sure temperatures and chemical concentrations are consistent. The three areas for which specialized control systems are useful are heating, chemical spiking and filtration.

Modutek high temperature re-circulating baths and constant temperature tanks heat up rapidly with a temperature rise of up to two degrees centigrade per minute. The operating temperature can range from 30 to 180 degrees centigrade and the temperature controller holds the temperature within plus or minus one degree centigrade. Quick heating helps improve throughput and accurate temperature control helps ensure high quality results.

For some chemical processes the concentration of chemicals can change during the process. Periodic spiking restores the chemical concentration to the desired level. Modutek has developed an innovative “bleed and feed” spiking method for the sulfuric acid and hydrogen peroxide (SPM) process.

The hydrogen peroxide of the SPM process decomposes and has to be replenished frequently. For traditional spiking, the mixture has an overall lifespan of only several hours. In Modutek’s clean tank/dirty tank using the “bleed and feed” spiking method, programmable amounts of mixture are drained from the dirty tank and transferred from the clean tank to the dirty tank. Programmable amounts of acid and peroxide are then added to the tanks. This method keeps the mixture fresh and increases the mixture’s lifespan to about one week.

In addition to controls for temperature and concentration, Modutek’s quartz tanks can reduce particle counts and wafer contamination. The quartz re-circulating tank can filter out particles down to 0.2 microns, improving output quality and reducing component failure rates.

Modutek’s quartz tanks are based on more than 30 years of experience and incorporate features to guarantee safe, reliable operation while delivering excellent wafer manufacturing results. Custom sizes, fast and even heating, reduced downtime and long vessel life help improve manufacturing facility performance and reduce costs.

Modutek continues to develop innovative techniques in the construction and use of quartz tanks for semiconductor manufacturing processing. The design of the quartz tanks and the associated advanced controls are a key factor in the production of semiconductor components of the highest quality. With extensive experience working with manufacturers in the development of advanced temperature, concentration and filtration controls, Modutek helps improve wafer manufacturing. Contact Modutek for a free consultation or quote on equipment designed to meet specialized manufacturing requirements.

How Megasonic Cleaning Improves Silicon Wafer Manufacturing Results

 5 Important Things to Know When Buying Wet Bench StationsTraditional silicon wafer cleaning uses aggressive chemicals to strip wafers and remove particles during semiconductor manufacturing. As semiconductor components such as processors, switches and memory chips become more tightly packed, removing all traces of contamination on the wafer surface becomes important for the production of high quality components and the reduction of component failure rates. Even sub micron particles can block the formation of a conducting path or a key structural component. Ensuring the removal of sub micron particles with traditional cleaning and rinsing has become challenging. Megasonic cleaning can remove even the tiniest particles from silicon wafers and improve process reliability.

How Megasonic Cleaning Works

Cleaning parts with megasonic sound waves in a cleaning solution is a quick and effective way of removing contamination from part surfaces. This cleaning method uses a range of high frequencies with the lower end used for less fragile pieces. The highest frequencies are used for the most delicate parts or parts with soft surfaces.

The sound waves in the cleaning solution create microscopic cavitation bubbles in the wave pressure troughs and the bubbles collapse in the wave peaks. When a bubble collapses, it emits a tiny but energetic jet of cleaning solution that dislodges contaminants and particles from part surfaces. Lower frequencies create comparatively large bubbles with stronger jets while the higher frequencies produce cleaning action with smaller bubbles and lower jet energy.

Because semiconductor components often include very delicate structures and soft layers of deposits on the silicon, only the highest frequencies deliver cleaning gentle enough to avoid structural damage and pitting. Megasonic cleaning takes place with frequencies around the 1 MHz level and higher and delivers effective cleaning without damage. The cleaning method is especially good at dislodging and removing particles as small as 0.1 microns with tiny bubbles breaking the particle’s adhesion to the underlying silicon wafer.

Modutek’s Megasonic Cleaning Solution

Modutek has partnered with Kaijo Shibuya Corporation, a world leader in Megasonic and ultrasonic cleaning technology, to create a line of Megasonic cleaning equipment suitable for use in semiconductor manufacturing. Megasonic cleaning systems can either be turn-key and integrated in fully automated wet bench station, or supplied as individual Megasonic generators and transducers.

Turnkey systems include the cleaning tank with the transducers already mounted while individual components can be integrated in existing semiconductor manufacturing lines. Equipment such as the Spot Shower, Mega Puck and Mega Tube allow operators to direct the Megasonic cleaning action to specific areas in the cleaning tank or on the surfaces of the silicon wafers. Megasonic cleaning reduces sub micron particle counts and can help produce better manufacturing results.

Modutek Megasonic Cleaning Features and Benefits

Systems using high frequency sound waves to clean silicon wafers have to be able to function at several frequencies, depending on the fragility of the parts to be cleaned. At the selected frequency, the megasonic transducers have to deliver enough power to fill the cleaning tank with sound waves, ensuring equal and consistent cleaning without dead spots. Ideally the bath and the transducers should be able to operate at elevated temperatures because some semiconductor manufacturing processes may use heated baths.

Modutek’s Megasonic cleaning systems operate at 950 kHz but frequencies between 200 kHz and 2 MHz are also available. High efficiency generators and full-power transducers deliver up to 1200 W of cleaning power and the systems can operate with bath temperatures of up to 140 degrees centigrade. These features deliver unparalleled cleaning performance without pitting or damage to silicon micro structures. The superior removal rate for particles down to 0.1 microns increases semiconductor component yields, reduces the number of defective components and improves product quality. For a free consultation or quote contact Modutek at 866-803-1533 or email [email protected].

Customized Table Top Chemical Process Tanks

 5 Important Things to Know When Buying Wet Bench StationsFor small operations and specialized applications requiring semiconductor fabrication capabilities it often doesn’t make sense to construct wet processing lines that produce products at volume. Table top process tanks can allow research labs, universities and start-up companies to produce single parts or low-volume output. These organizations may need proof of concept components or prototypes for testing. Small chemical process tanks deliver the capability to fabricate such products in a customized unit designed for the specialized applications.

Customization is the Key to Effective Table Top Systems

Table top chemical process tanks for specialized output are heavily customized to reflect their unique purposes. Tank size, chemicals used, controls, heating and circulation are all adapted to the particular use. Because Modutek designs and builds all of its wet bench equipment in house, the company is ideally situated to undertake the customization required for this special application. Modutek has been working with customers to provide table top chemical process tanks that are easy to install and use safely, for example under an existing fume hood. Customers can purchase a complete unit with the special features and characteristics they need.

Features and Benefits of the Modutek Table Top Systems

Modutek’s table top chemical process tanks are a further development of their wet bench Teflon tanks but other configurations are available. Specific features include the following:

  • Installation.The tanks are mobile and can be placed wherever convenient for safe operation. Sizes and shapes are fully customized to match the use and the space available.
  • Circulation.Tanks can be static or fitted with overflow circulation and filtration. Circulating tanks have a 360 degree serrated overflow weir and an all-Teflon fluid path. Both static and circulating tanks are made of all PFA Teflon.
  • Heating.Tanks are ambient temperature or temperature controlled. For heated tanks, the operating temperature is 30 to 100 degrees centigrade. The heat-up rate is 2 to 3 degrees per minute and the temperature control is accurate within plus/minus 0.5 degrees centigrade.
  • Process.The tanks are usually Teflon tanks for KOH and related wet processes. Acid and solvent process capabilities are also available.
  • Wafer Holders.The systems usually come with standard carrier sizes for single or double capacity. Custom wafer holders are available.
  • Controls.Process controllers to handle temperature and timing are available. Inputs can include level switches, temperature alarms and a drain interlock. Remote operation is also possible.

Modutek can assemble the table top unit with the required features exactly as specified by customers. Benefits include reliable and safe operation, consistent process variables and repeatable outputs and results.

Table Top Systems Designed and Built to Meet Requirements

As a leader in wet bench technology, Modutek has the in house expertise to design and build innovative semiconductor fabrication equipment such as table top chemical process tanks. The company can draw on its comprehensive line of wet bench stations to adapt standard equipment for such special applications. Because Modutek engineers and technical personnel create these customized units, the company can provide complete after sales support and repair services. Contact Modutek for a free quote or consultation to discuss your specific chemical process application requirements.

 

Selecting the Right Acid Neutralization System for Your Application

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

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

How Acid Neutralization Systems Work

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

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

Continuous Flow Neutralization Systems

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

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

Batch Neutralization Systems

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

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

Modutek’s Acid Neutralization Systems

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

5 Important Things to Know When Buying Wet Bench Stations

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

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

1. Automated Wet Bench Stations

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

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

2. Stainless Steel Solvent Stations

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

3. Chemical Delivery Systems

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

4. Rinsing and Drying

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

5. Special Etching or Cleaning Equipment

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

Modutek Can Help With the Final Selection

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