Category Archives: Wet Bench Equipment

How Standard Clean Particle Removal (SC1 Clean) is Supported in a Wet Bench Process

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How Standard Clean Particle Removal (SC1 Clean) Is Supported in a Wet Bench ProcessEditor’s Note: This article was originally published in April 2015 and has been updated with additional information and reposted in April 2023.

The SC1 clean process is a widely used method for removing particles and other contaminants from silicon wafers. This process involves using a solution of ammonium hydroxide and hydrogen peroxide, which is heated to a specific temperature and then used to clean the wafers. In this article, we will discuss what the SC1 clean process is, its benefits and advantages, and how it is supported in Modutek’s wet bench equipment.

What is the SC1 Clean Process?

SC1 Clean is the first step in the RCA clean, the procedure required before the high-temperature processing of silicon wafers. Organic impurities attached to silicon, oxide, and quartz surfaces by the solvating and oxidizing actions of NH4OH and H2O2 respectively are eliminated by the particle-removing solution, SC1 Clean. This solution starts a slow regeneration process whereby the silicon wafer’s original surface layer of oxide is broken down and replaced with a new layer. This regeneration process is a highly significant part of particle removal.

SC1 solution is used at 75 or 80°C for approximately 10 minutes. It is composed of:

  • 5 parts deionized water
  • 1-part NH4OH
  • 1-part H2O2

The cleaning procedure begins by heating a mixture of deionized water and NH4OH up to 75°C. Then H2O2 is added and the mixture is allowed to bubble violently before use. The silicon wafer is then soaked in the solution for 15 minutes. After this time the silicon wafer is rinsed in a container of deionized water to clean off the solution. The water is changed several times in order to prevent any removed residue from clinging back on to the surface of the silicon wafer. With the new oxide layer on the surface comes ionic contamination that should be cleaned off in the next steps of RCA Clean.

Benefits and Advantages of the SC1 Clean Process

The SC1 clean process offers several benefits and advantages for semiconductor manufacturers. It provides an efficient method for removing particles and other contaminants from wafers. This can result in improved yields, reduced defect rates, and higher product quality. Additionally, the SC1 clean process is highly repeatable, allowing manufacturers to achieve consistent cleaning results across multiple batches of wafers.

Another advantage of the SC1 clean process is that it is environmentally friendly. The process uses only a small amount of chemicals, which are relatively safe and easy to handle. Additionally, the chemicals used in the SC1 clean process are readily available and relatively low cost, which can result in significant cost savings for manufacturers.

Support for SC1 Clean Process in Modutek’s Wet Bench Equipment

Modutek’s wet bench equipment is designed to support the SC1 clean process and other standard clean processes used in the semiconductor industry. The company’s wet bench equipment is designed to provide precise control over the temperature, concentration, and flow rate of the SC1 clean solution, ensuring optimal cleaning results.

Wet bench equipment from Modutek is also designed to provide maximum process flexibility, allowing users to customize the SC1 clean process to meet their specific cleaning needs. This can include adjusting the cleaning time, temperature, and concentration of the SC1 clean solution to achieve the desired cleaning results.

Overall, the SC1 clean process is an efficient and effective method for removing particles and other contaminants from silicon wafers. With its numerous benefits and advantages, including improved yields, reduced defect rates, and higher product quality, the SC1 clean process is an ideal choice for semiconductor manufacturers looking to improve their manufacturing processes. With Modutek’s wet bench equipment, users can be confident in achieving optimal cleaning results while maintaining maximum process flexibility.

Using Megasonic Cleaning with SC1 Clean

The use of megasonic cleaning is often used with the SC1 cleaning process to improve results. Modutek’s partnership with Kaijo Corporation provides cutting-edge high precision megasonic cleaning technology. Megasonic cleaning can remove particles as small as 0.1 µm with Modutek’s Indirect (MSI Series) bath design. Another option is to use Modutek’s Direct (MSD Series) with the Teflon coated Megasonic transducer. When placed in the cleaning tank, the transducer plate is ideal for using SC1 Clean and is easily accessible for installation and upgrades.

Modutek’s Megasonic cleaning features include:

  • Automatic frequency tracking system
  • High-efficiency generator
  • Upper and lower limit controls
  • Available frequencies: 430kHz and 950kHz

Modutek’s Experience and Expertise

Modutek has been in the business of designing and supplying wet process equipment for over 40 years. This history is sustained by experts who will work with you from design to final equipment installation. Contact Modutek for a free consultation to discuss your process requirements.

How to Order a Wet Bench for Your Specific Process Requirements

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How to Order a Wet Bench for Your Specific Process RequirementsWet processing used in semiconductor manufacturing includes many complicated process steps which need to be taken into account when ordering new wet bench equipment. When selecting a supplier, experience and capabilities have to be evaluated. Physical requirements such as space and output volume are essential. The degree of automation required also plays a significant role. Finally, there are special requirements for specific processes that have to be evaluated. You need a competent manufacturer of wet bench equipment to help you get the wet process stations you need.

  1. Look for a Manufacturer with a Proven Track Record and In-House Capabilities

Manufacturers who can help you with your choice of a wet bench should have in-house expertise with a complete line of wet bench equipment, including their own software. An experienced manufacturer will be able to advise which stations satisfy your requirements and what options you should consider. In-house design and manufacturing capabilities allow the manufacturer to provide complete after-sales service and support.

  1. Make Sure Your Choices Don’t Impose Unwanted Physical Constraints

The chosen wet bench has to satisfy requirements for space, wafer size, and wafer throughput. If space is tight, a compact design or designs combining functions such as rinsing and drying can be considered. In any case, the station has to be able to process the proposed wafer sizes. Custom dimensions for equipment can be explored with a manufacturer that has customization capabilities.

Wafer throughput is often critical for the viability of the facility. It is influenced by the number of cassettes that can be processed in a bath and process duration. When projected throughput is borderline, an experienced manufacturer can often suggest special equipment, automation, or advanced process technology to reduce processing time and speed up production.

  1. The Degree of Automation Depends on How the Wet Bench Will Be Used

Wet benches for organizations such as research labs, small manufacturers, and high-volume manufacturing facilities have different automation needs. Labs often produce prototypes or small volumes for testing. A manual station may be the best solution for this kind of operation. Small manufacturers typically produce single units or small batches. A manual station could satisfy their needs, but a semi-automated station could allow them to run consistent batches while saving on the full-automation cost of robotics. High-volume operations will usually benefit from fully automated stations because they improve efficiency, reduce product defects and deliver excellent consistency over long runs.

  1. The Wet Bench Equipment Needs to Support the Wafer Manufacturing Process

Depending on the chemistry to be used, the selected wet bench equipment has to support the process. Wet process silicon wafer fabrication can use different chemical processes to clean, etch, develop and strip the wafers. Special equipment and accessories are used for various applications.

  • Acid process tanks are made from quartz or Teflon, while solvent processes require stainless steel tanks. Tanks are made with high-purity materials and are designed to minimize particle contamination.
  • Quartz tanks are used for cleaning, etching, and stripping. They can support high-temperature applications.
  • Teflon tanks are used for etching applications. They can be ambient temperature tanks or heated with re-circulation.
  • Silicon nitride wet etching requires special control features because adding de-ionized water to maintain the acid concentration can be dangerous.
  • Quick dump rinsers speed up the process while reducing the use of de-ionized water and avoiding particle entrapment.
  • Temperature-controlled circulating tanks are required for applications where the etch rate depends on the temperature. The baths are heated to achieve a higher etch rate and the temperature has to remain constant while the process is running.

Modutek Has the In-House Expertise and Capabilities to Help Choose a Wet Bench

As a leading semiconductor equipment manufacturer with over 40 years of experience, Modutek can recommend and provide the right equipment for your specific process requirements. Modutek has a complete line of wet processing equipment and can supply what you need and ensure it provides the performance you want. Contact Modutek for a free consultation and quote.

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.

Reasons to Use a Wet Bench Manufacturer with In-House Expertise

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When dealing with third-party distributors who offer wet bench stations built by someone else, customers often pay more and get less. A wet bench manufacturer that designs and builds its own wet bench equipment in-house develops the expertise and capabilities needed to satisfy customer requirements. The manufacturer can respond directly to customer requests and design tailored or full custom solutions to meet specific requirements. With a wet bench manufacturer who has in-house expertise, customers can get exactly what they need.

Customizing Wet Bench Designs to Match Customer Needs Requires In-House Expertise

Semiconductor manufacturers and research labs often work with tight specifications that can’t be satisfied with standard wet bench stations. Customization requirements can range from space limitations to special robotics and software to control specific processing requirements. When manufacturers carry out their own design work, they are aware of the possibilities and limitations of specific semiconductor manufacturing processes. They can then easily advise customers what solutions are available and help choose the best one. Customers end up with optimized designs for equipment that works the way they want.

Building Custom Wet Bench Stations Requires Extensive In-House Manufacturing Experience

When wet bench manufacturers carry out their own design work, they know how to build what they design. Their designs are based on extensive in-house manufacturing experience gained over many years of building wet bench stations. They know what works and have been able to feed this experience back to their design engineers. With suppliers that carry out both design and manufacturing in-house, customers get wet bench equipment that is designed to their specifications and that is based on extensive manufacturing experience.

Wet Bench Manufacturers Can Provide Superior Customer Service and Support

With in-house design and manufacturing personnel, companies can provide knowledgeable customer support and after-sales service. When design, manufacturing, and process expertise resides in-house, service personnel know who to call if they run into problems. Support and service people will already be familiar with their own standard equipment and they have direct access to the design and manufacturing specialists that can guide them to find the best solutions for after-sales issues.

For wet bench technology, it’s especially important that the manufacturer also designs and writes the software that runs the process. Automation is becoming an increasingly important part of wet process equipment. Even if process steps are initiated manually, the software may be responsible for timing and dosages. For fully automatic stations, the software runs the whole process. Only the specialists who write the software can perform effective troubleshooting if there are unexpected operations or results. The wet bench manufacturer’s in-house expertise has to include the software.

Modutek Has Extensive Expertise Based on Long-Term Design and Manufacturing Experience

With over 40 years of experience in designing and building wet bench stations for industrial clients, Modutek is a leading wet bench manufacturer. Modutek works closely with customers to develop new technical solutions for current problems. In addition, Modutek actively leads technological innovation in fields such as wet bench process control, efficient chemical use, and reduction in particle contamination of silicon wafers. When customers identify new issues with semiconductor manufacturing, Modutek can often contribute to finding the best solutions.

Based on this long-term experience, Modutek personnel have developed extensive expertise in wet bench technology. The company designs its own equipment, including the development of its automation software. Wet bench stations are assembled and tested in-house at Modutek’s facility in San Jose which allows for easy customization. Modutek has a product line of standard equipment, including process tanks, chemical handling equipment, and complete wet process stations, the company can change dimensions, materials, robotics, process variables, and operator interfaces in accordance with customer requirements. In-house expertise is the key to these capabilities.

Important Things to Know Before Buying a Wet Bench Station

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There are a number of process and production requirements that need to be considered before buying a wet bench station. In addition to knowing which process chemicals are needed, you also need to decide on the degree of automation and whether any customization is needed for your station. If your application requires the use of aggressive chemicals, you also need to consider chemical delivery, handling, and disposal systems. Once silicon wafers have been cleaned or etched on the wet bench station, you have to know how the rinsing and drying process will be performed while keeping contamination to a minimum. The kind of semiconductor manufacturing you’ll be carrying out determines the type of wet bench station, and how you plan to run your facility impacts many of the other decisions you’ll have to make.

The Process Determines the Type of Station

Depending on the details of the semiconductor manufacturing process you’ll be using, you may be etching or cleaning wafers with acids and bases or you may be using solvents. Chemicals such as hydrochloric acid or hydrogen peroxide are extremely corrosive and require stations made of polypropylene and tanks made of inert materials such as quartz. Stations that use solvents such as acetone or IPA are made from stainless steel and the chemicals are not as aggressive.

Chemical Handling Systems Increase Safety

When you install chemical handling systems with your wet benches, you avoid spills and eliminate human error in dosages and mixing. Chemical handling includes delivery to the process, neutralization of the chemicals after use, and safe disposal of the waste. Chemical handling systems come in many sizes and can handle a variety of tasks. An experienced manufacturer of wet process equipment can advise you regarding the best systems for your application.

Automation Can Help Improve Performance

Wet process automation can range from stations that perform a few tasks independently to fully automated stations that run the whole process by themselves. For large production runs, full automation can save time and ensure consistency. For batch processing or the development of prototypes, semi-automated stations run standardized tasks while operators take over manual control where needed. You have to decide how you are going to run your facility and whether a high degree of automation is appropriate.

Specialized Sub-Systems Can Meet Your Unique Process Needs

The complexity of semiconductor manufacturing means that each facility has unique features and special requirements. Often specialized subsystems can improve facility performance. For example, a quick dump rinser speeds up rinsing while a unit that combines rinsing and IPA vapor drying can reduce particle contamination. If particle count reduction is critical for your process, Megasonic cleaning using high-frequency sound waves can reduce particle counts to a minimum. Look at specialized sub-systems to see if you can use any of them for your process.

Customization Can Help You Get Exactly What You Need

When standard wet benches don’t quite do what you want, it’s time to work with a wet bench manufacturer that designs and builds their own equipment. When design and assembly are carried out in-house, the manufacturer has the capability to adapt standard equipment to exactly meet your requirements. It could be something simple such as a custom tank size and shape or more complex features such as special automation programming for extra process steps. Experienced manufacturers can customize your equipment and can advise you on what equipment is best suited for your application before building it to your requirements.

Modutek Has the In House Expertise and Experience

Modutek has been designing and building wet bench stations and equipment for over 40 years and can advise customers to make sure they get the equipment they need. As one of the leading semiconductor equipment manufacturers, Modutek’s in-house expertise allows them to develop the specialized sub-systems needed by customers. When considering the purchase of a wet bench station, Modutek can help you choose the equipment and make sure it operates the way you want.

How Stainless-Steel Stations Provide Safe Solvent Processing

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How Stainless Steel Stations Provide Safe Solvent ProcessingSolvents used in semiconductor manufacturing can remove oils and organic contaminants from silicon wafers in preparation for further processing steps. Acetone, isopropyl alcohol (IPA) and ethylene diproxitol (EDP) are solvents commonly used to clean wafers, remove photoresists, and in pattern transfers for the creation of microscopic structures on the wafer. The solvents are inflammable and require special safety measures to reduce the risk of fire and explosion, and they have to be disposed of safely. Stainless steel wet benches incorporating stainless steel processing tanks are an ideal solution for safe processing with solvents.

Safety Requirements for Stainless Steel Wet Bench Stations

The safe operation of stainless-steel solvent stations has to include the following safety features:

  • fire suppression
  • fire fighting
  • protection against exposure
  • protection against leaks
  • safe disposal

Fire is one of the principal safety hazards because solvents or their vapors can catch fire and explode. Fire suppression measures can include electrical design limiting the potential energy of sparks so they can’t ignite solvents and designing equipment to Class 1, Division 2 specifications.

Firefighting equipment has to be able to extinguish fires, should they occur. For inflammable liquids such as solvents, gas-type fire systems such as those using carbon dioxide are needed. It’s critical to have corresponding safety protocols and procedures to ensure workers are evacuated before triggering the extinguishing gases because the firefighting gas displaces oxygen and could cause suffocation.

Many solvents are harmful when workers are exposed to them over extended periods, either through direct contact or through breathing the vapors. A complete enclosure of the solvent processing tanks along with effective exhausts and leak detection limits the amount of solvent to which workers can be exposed.

Disposal of used solvents has to be carried out safely and according to environmental regulations. The disposal can be on-site if the facility has the corresponding capability, or the waste can be stored in a carboy for pick-up by a specialized disposal company.

Modutek Stainless Steel Wet Bench Stations are Safe and Customizable

Modutek stainless steel stations are made from 304 stainless steel and are available in fully automatic, semi-automatic, or manual versions. Dry to dry and fume hood designs are possible, and the stations feature casters and leg levelers. SolidWorks simulation software calculates the process flow characteristics and all design, assembly, and testing are carried out in-house. The stations can be built to the size and length required and extensive customization is available to exactly match customer requirements.

On the safety side, all stations are wired to the NFPA 70 & 79 standards and designed with fire suppression. Safety interlocks with emergency power off buttons are included. The station tanks have a one-inch lip exhaust and a continuous flow deionized water manifold. PVC safety shields are included and the stations have a nitrogen head case purge with Photohelic pressure interlocks. A Teflon nitrogen gun and deionized water hand spray are also included.

As a leading wet bench manufacturer, Modutek works closely with customers to determine how best to help them meet their objectives. Careful wet bench design can increase productivity and output while reducing costs. Modutek is focused on delivering wet bench equipment such as stainless-steel solvent stations using the best available materials and safe, high-quality designs.

With over 40 years of experience in the manufacture of wet benches and with the ability to carry out all design, assembly, and testing work in the company’s San Jose facility, Modutek is the ideal partner for semiconductor fabrication facilities and research labs. Modutek’s in-house experience allows for easy customization and safe execution of wet process semiconductor manufacturing projects of all kinds. Contact Modutek for a free consultation to discuss your specific solvent processing requirements.

Solvent Processing Using Stainless Steel Stations

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Solvent Processing Using Stainless Steel StationsManufacturing processes using volatile solvents have to be specially designed to minimize the risk of explosions or fire. Solvents such as acetone or alcohol are used to clean parts, dissolve materials and extract substances. Modutek’s stainless steel stations meet strict safety regulations that reduce the risk of ignition of the solvents or their vapors and they have additional features and interlocks in an integrated approach to operator safety. As a result, the stainless steel stations can be installed safely in both new and existing facilities for solvent processing.

Special Design Measures Ensure Safe Solvent Station Operation

Safe stainless steel solvent station operation depends on specific design measures that reduce the risk of fire or explosion. Modutek’s stations satisfy safety regulations and include design features that improve safety based on extensive experience in wet bench processing. Special safety design measures can include the following:

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

How Stainless Steel Solvent Processing Stations Operate Safely and Reliably

Modutek’s Series SFa and Sa Stainless Steel Stations for solvent processes meet all the safety requirements of the applicable regulations. Made of electropolished stainless steel, the stations satisfy the National Electrical Code Class 1 Division 2 Group D standard for hazardous locations. The baths feature PVC safety shields, N2 head case purge and an auto lid option. They are designed for operator safety and prioritize safe containment and disposal of volatile solvents.

The SFa series station uses a temperature controlled re-circulating bath while the Sa series is constant temperature. The baths have a temperature control precision of plus/minus 1 degree centigrade, a heat-up rate of 2 degrees centigrade per minute and an operating temperature range of 30 to 100 degrees centigrade. Bath heaters are rated from 2 to 6 kW depending on the tank size. With precise temperature control and a fast heating rate, the baths can improve yield and produce high-quality process output.

In addition to the safety features and temperature control characteristics, the baths have multi-sided heating elements, a 360 degree overflow weir, operating interlocks, process control thermocouples and liquid level sensors. The tanks are available in standard sizes from about 8 inches to 24 inches a side. Custom sizes are also available.

Modutek’s Can Provide Solvent Processing Stations to Satisfy Customer Requirements

With 40 years experience in designing wet benches for semiconductor manufacturing, Modutek supplies stations made with high-quality materials designed for safety, ease of use and reliable operation. As a leading wet bench manufacturer, Modutek is constantly innovating to incorporate the latest advancements in its wet process equipment including its solvent processing stations.

Modutek can examine solvent processing needs and recommend stations for specific applications. A complete line of standard baths and the ability to customize as required means the company can build solvent processing stations to meet special customer needs. Modutek builds all its own equipment and designs and writes its own software in-house. As a result, Modutek can give expert guidance on what is required and follow up with complete customer support and service for all its products. For a free quote or consultation to discuss your specific requirements contact Modutek at 866-803-1533 or email [email protected].

Improving Wafer Manufacturing Processes with Automated Equipment

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Improving Wafer Manufacturing Processes with Automated EquipmentAutomated wafer fabrication equipment can improve semiconductor manufacturing facility performance, but all the associated process settings must be programmed properly. Before the manufacturing process can be implemented on a fully automated wet bench station, the settings, timing and other parameters have to be fine tuned. As circuit geometries and micro-structures become smaller and more tightly packed, the chemical concentrations, temperature levels and timed intervals affecting the etch rate become more and more critical. Fully automated equipment can precisely and reliably run a semiconductor manufacturing process once the correct variables are determined and programmed.

Manual Operation Can Determine the Settings for the Process Variables

Once wafer fabrication processes such as KOH etching are chosen, the process variables can be selected. Etching can be either isotropic or anisotropic and etching speed or precision can vary. Other factors may come into play as well. Initially it makes sense to run the new process on a manual station so that the process results for rough settings of basic variables such a concentrations, temperature and timing can be determined. These variables can then be adjusted to get an initial and acceptable process result.

Semi-Automatic Operation Can Fine Tune the Process

After determining the rough settings of the basic variables in manual operation, transferring to semi-automatic operation to optimize the process steps can save time. Those variables that will no longer change can be programmed into the semi-automatic software control while the others can be adjusted manually to get the best process result. In this way, as each process step is optimized, it can be programmed so that when optimization is complete, the process is ready to run on fully automated wafer processing equipment.

Fully Automated Operation Improves Semiconductor Manufacturing Facility Performance

Fully automated wet process stations for which the process has been optimized in manual and semi-automated operation can help improve overall production facility performance in the following ways:

  • Programmed settings ensure that the process is repeatable for different batches
  • Use of wet processing simulation software during optimization helps ensure accurate process parameters
  • Full automation eliminates human error
  • Precise dosages of chemicals and accurate timing results in fewer defective products
  • Throughput and wafer yields are increased

The programmed settings can be used again to get an identical result and they can be used for similar applications with minor adjustments. Instead of relying on operators to prepare etching baths, the fully automated station mixes the required chemicals quickly, safely and reliably, always the same way and without waste or spillage. The result is precise control over the process steps, fast execution without delays and high output quality.

Improved Output Relies on Optimized Software and Fully Automated Stations

Using an optimization strategy with manual and semi-automatic operation and running the optimized process on fully automated wafer fabrication equipment can lead to continuous improvement in semiconductor manufacturing operations. As new processes are brought online and optimized, they replace older versions that may not use chemicals as efficiently, may rely on some manual input or may not have the same precise and reliable execution as the fully automated stations. Tailor-made software working with fully automated wet process equipment can result in such continuous improvements.

With 40 years of experience in wet process technology and extensive in house expertise from manufacturing its own equipment, Modutek is ideally situated to supply fully automated equipment that improves semiconductor manufacturing output. The company has a complete line of standard and custom-built wet process equipment and the SolidWorks software used to calculate process parameters is programmed in house. Working closely with its customers, Modutek designs and builds its fully automated stations and programs the corresponding software to help them meet their goals for continuous improvement. Contact Modutek for a free quote or consultation on selecting equipment that supports your specific manufacturing process requirements.

How Specialized Wet Bench Equipment Improves the RCA Clean Process

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How Specialized Wet Bench Equipment Improves the RCA Clean ProcessThe RCA clean process removes contaminants from the surface of silicon wafers so that additional wet process semiconductor manufacturing steps can take place. The process consists of two steps, with the SC1 step removing organic compounds and the SC2 step dislodging any remaining metallic residues or particles. Specialized wet benches ensure that contaminant and particle removal is as complete as possible and the silicon wafers remain clean. To accomplish this, the equipment carefully rinses away contaminants and minimizes the handling of the wafers. Automation can be used to replicate process parameters reliably and consistently. Modutek can supply both standard and customized specialized equipment to carry out the RCA clean process.

RCA Clean SC1 Removes Most of the Wafer Surface Contamination

The SC1 cleaning step uses chemicals to dissolve impurities while leaving the underlying silicon surface unaffected. The wafers are placed in a solution containing equal parts of NH4OH (ammonium hydroxide) and H2O2 (hydrogen peroxide) in five parts of de-ionized water. The solution is heated to about 75 degrees centigrade and the wafers are left in the solution for ten to fifteen minutes. Organic residues are dissolved and particles are removed. A thin layer of silicon oxide forms on the wafer and there is some contamination with metallic ions and particles.

RCA Clean SC2 Removes Metallic Impurities

For SC2, the newly cleaned wafers are placed in a bath containing equal parts of hydrochloric acid and hydrogen peroxide in five parts of de-ionized water. The exact ratio may vary depending on the application. The bath is heated to about 75 degrees centigrade with the wafers soaking for about ten minutes. The solution specifically eliminates alkali residues, metal hydroxides and other metallic particles. The wafers are now completely clean and free of all types of particles.

Wafer Cleaning Equipment Has to Fulfill Specialized Functions

Specialized equipment is needed to carry out RCA clean process steps effectively. The required chemicals have to be delivered in the right quantities to the cleaning baths and then, when the chemicals are no longer needed, they have to be neutralized and disposed of safely. The concentration of the chemicals, the bath temperature and the timing are all important for being able to subsequently reproduce the desired cleaning performance. Contaminants and particles have to be rinsed away and filtered out. Key features of effective cleaning are a low particle count on the wafer surface and a resulting low rejection rate for fabricated wafers.

Modutek’s Wet Process Equipment Provides Specialized Features

Modutek’s wet benches and chemical stations support both of the RCA cleaning steps. Chemical delivery systems ensure that the right amounts of chemicals are supplied to the process safely and that waste chemicals are neutralized before disposal. The FM4910 material of construction keeps particle contamination low and is safe to use with the acid and base processes of RCA clean. All baths include a continuous flow de-ionized water chamber with chemical circulation and filtration to rinse away and remove contaminants. The SolidWorks flow simulation software lets operators calibrate dosages precisely and store settings for future use.

As well as fulfilling customer needs from its extensive line of wet process equipment, Modutek can build custom systems for specific applications. Customers who wish to incorporate drying, etching or stripping functions as well as RCA clean in their process lines can rely on Modutek to design and build exactly what they need.

With 40 years of experience in the wet process and technology sector and one of the leading semiconductor equipment manufacturers, Modutek has the expertise in house to provide specialized equipment for the RCA clean process and other semiconductor manufacturing applications. Customers can count on Modutek to help them find effective solutions and supply the corresponding equipment. Contact Modutek for a free quote or consultation to discuss your process equipment requirements.

How Specialized Manufacturing Equipment Provides Safety for Using Solvents

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Semiconductor manufacturing solvent applications use specialized wet bench equipment to reduce the risk of fire and explosions from volatile solvents such as acetone. Solvents are used for operations that include stripping, cleaning and pattern transfers, and their inflammable nature means that the equipment has to meet stringent safety regulations. Safety measures focus on ensuring electrical components don’t ignite solvents or their vapors and operator safety through training. Additional safety measures include limiting access to sensitive areas and installation of fire extinguishing equipment. These safety measures provide integrated approach to solvent handling and use and ensure stainless steel solvent stations can be installed and operated safely in new fabrication lines or with existing equipment.

Special Features Satisfy Regulations and Keep Operators Safe

When working with inflammable solvents, safety regulations require specific features and additional operating measures to keep workers safe. These features can include the following:

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

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

• Use of carboys to collect solvent waste.

• Use of safety interlocks to ensure safe operation.

• Process monitoring with safety alarms for dangerous conditions.

• Detection of liquid spills.

• Emergency power off mushroom button.

• Wiring per NFPA 70 and 79.

• Auto lids to seal off chemical containers.

• Access controls to ensure only qualified personnel can operate the equipment.

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

An experienced manufacturer of wet bench equipment incorporates these features in all their solvent station designs to make sure an integrated safety concept allows for safe operation.

Modutek’s Stainless Steel Solvent Stations Meet All Safety Requirements

Modutek manufactures the SFa and the Sa series of stainless steel solvent baths for solvent applications including IPA, acetone and resist strippers. The baths meet National Electrical Code Class 1 Division 1 Group D requirements for hazardous locations and are specially designed for safe operation. Made from 304 stainless steel, the baths are inert for the solvents used. The SFa bath is a temperature controlled recirculating bath while the Sa bath is constant temperature.

The baths both include all the required safety features for safe solvent operation. With NFPA 70 and 79 wiring, fire suppression, N2 head case purge, 1-inch lip exhaust and PVC safety shields, the baths are configured to keep workers safe. Operational safety is ensured with safety interlocks, an emergency off mushroom button, a Teflon N2 gun, a de-ionized water hand spray and a continuous flow de-ionized water manifold.

While maintaining a high level of safety, the stations deliver improved yields with fast heating and accurate temperature control. With an operating temperature of 30 to 100 degrees centigrade, heaters can achieve a temperature increase of up to 2 degrees centigrade per minute. Temperature control accuracy is plus/minus 1 degree centigrade for excellent process control and reproducibility.

Modutek’s solvent stations are available in fully automated, semi-automated or manual versions. The fully automated stations further increase safety by eliminating operator error, reducing spills and ensuring that a process runs with the correct dosages and timing. Semi-automated stations give customers the benefit of robotic operation without paying the price of full automation. Manual stations retain all the safety features but don’t include automation and are less expensive. Each station can be customized to exactly meet the specific requirements of the customer.

As a wet bench manufacturer with extensive experience in semiconductor manufacturing technology, Modutek can design and build both standard and customized equipment that is safe to operate while delivering top performance. Modutek can provide free consulting to help customers clearly define needs and then propose wet bench components, standard systems or custom installations that meet the highest safety standards.