Category Archives: Wet Processing Equipment

How the IPA Vapor Dryer Provides Superior Wafer Processing

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After 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.

How Megasonic Cleaning Improves Silicon Wafer Manufacturing Results

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Traditional 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].

How Quartz Tube Stations Work and the Benefits They Provide

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Among the many processing steps involved in the manufacture of semiconductor components are high-temperature operations such as diffusion of materials into the silicon wafers. Quartz tubes are an ideal vessel for these process steps because the tubes can withstand the temperatures required and are inert enough to minimize contamination.

Typically, the silicon wafers are placed into a horizontal quartz tube large enough to hold the wafers and their supports. The quartz tube cleaning station can heat the contents up to over 1000 degrees centigrade. In a diffusion process, impurities such as phosphorus are introduced into the quartz tube.

Once the process is complete, the quartz tube is contaminated and has to be cleaned for the next batch of wafers. Complete and reliable cleaning is essential for the semiconductor manufacturing process because contaminating particles can cause defects in the semiconductor components or result in inferior product quality.

How Quartz Tube Cleaning Works

Quartz tube cleaning is a custom-designed process because the dimensions and cleaning requirements of quartz tube furnaces can vary widely. Quartz tubes are mechanically delicate, so they have to be handled with care. At the same time the cleanliness requirements are rigorous so that all traces of the contaminating material have to be removed. Finally, the rinsing and drying process must not introduce any new particles into the quartz tube. The cleanliness of the tube directly impacts the performance of the semiconductor manufacturing facility.

In horizontal quartz tube cleaning stations, the tube is inserted into the cleaning enclosure and cleaned with an acid spray. The acid dissolves and removes the contaminant from the high-temperature furnace. A subsequent rinse cycle removes all traces of the acid from the tube surfaces. A drying cycle can speed up drying without introducing particles into the cleaning enclosure. Mechanical handling of the tubes reduces the possibility of breakage due to human error and minimizes opportunities for the entry of contaminating particles. Safety interlocks, exhaust fans and safety shields protect operators from the hazardous chemicals.

Modutek’s Quartz Tube Stations Offer Numerous Benefits

A key factor in effective customization of quartz tube cleaning stations is that the supplier has to design and build the stations so that they can make the required adjustments. Modutek designs and builds all process, etching and cleaning components in house at the company’s San Jose, California facility. Equipment is customized exactly according to the requirements of the specific application.

In addition to providing customized equipment, Modutek can supply the degree of automation required by the customer. Cleaning process steps can be initiated manually or the whole cycle can be completely automated. Different steps can initially be run and timed manually and then, when optimum performance is reached, automated operation can be locked in.

Full automation reduces human error and keeps operators safe by allowing them to monitor the cleaning process remotely. Automated quartz tube cleaning stations will run the same cleaning job exactly the same way, with identical timing and dosages. Results from an automated system are predictable and uniform and the system can be programmed for the best possible results.

Modutek’s horizontal quartz tube cleaning stations are an excellent solution for semiconductor manufacturers. Rugged and reliable with one-piece construction up to ten feet long, the basic units offer many options for additional features. Once the requirements of the cleaning application are satisfied, Modutek can offer design add-ons such as holding tanks, automation features, a T/C sheath cleaner or a bottle washer. Modutek is a leading semiconductor equipment manufacturer that provides continuous product innovations and improvements along with the highest degree of customer service and support.

Reviewed and Approved by Douglas Wagner
President & CEO, Modutek Corporation

How the IPA Vapor Dryer Improves Wafer Processing Results

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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.

 

 

 

Improving Wafer Processing with Automated Equipment

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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 Megasonic Cleaners Improve Silicon Wafer Manufacturing

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The cleaning of silicon wafers is one of the key process steps needed in semiconductor manufacturing. This as become even more critical as micro circuit geometrics continue to shrink on 300 mm silicon wafers. Sub micron particles must be removed from the wafer substrate without damaging the delicate microcircuit structures from previous process steps. Particles that remain may result in defective semiconductor components that don’t work or low quality devices that have sub-par performance.

Incorporating Megasonic cleaning technology in the wafer cleaning process effectively removes sub-micron particles and contaminants without damaging or altering the wafer surface. In order to clean effectively selecting the appropriate frequency and power level is important. Modutek has partnered with Kaijo Shibuya Corporation to incorporate their high frequency Megasonic cleaning systems directly into Modutek’s wet bench process equipment. The wet bench stations combine chemical cleaning processes such as RCA or SC1 with Megasonic cleaning in the megahertz range to remove particles and contaminants down to 0.1 microns. Depending on the cleaning temperature and duration, cleaning efficiencies of over 99 percent can be achieved.

How Megasonic Cleaning Technology Works

Megasonic cleaning systems use a high frequency generator to create high frequency sound waves through the use of a transducer that is immersed in a liquid filled cleaning tank. The compression waves that are generated from the sound create high pressure at their peaks and low pressure at their troughs. Small cavitation bubbles appear in the low-pressure troughs and collapse in the high-pressure peaks. The action of the bubbles in the liquid effectively removes contaminants and particles from the exposed surfaces.

Lower ultrasonic frequencies in the 20-100 kHz range produce relatively large energetic cavitation bubbles which can cause damage to delicate part surfaces. For applications associated with semiconductor cleaning, megasonic cleaning in the megahertz range is required since it generates much smaller energetic cavitation bubbles. The gentle cleaning action from bubbles at the megasonic frequency range will effectively clean without damaging the wafer surface.

The action of cavitation bubbles in the cleaning tank will also agitate the cleaning solution which reduces boundary layers and allows the cleaning solution access very small surface areas such as crevices and complex shapes. The use of megasonic cleaning in silicon wafer manufacturing improves the overall effectiveness of the chemical cleaning solution by removing small sub-micron particles through the action of energetic bubbles.

Modutek’s Use of Megasonic Cleaning

Modutek has used their partnership with Kaijo Corporation to continually improve the cleaning performance of their wet benches by using Kaijo’s Megasonic Cleaning technology. Kaijo is a world leader in megasonic and ultrasonic cleaning systems and Modutek incorporates the Quava megasonic cleaning system generator into their wet bench stations for this application.

The Megasonic cleaning system incorporated within Modutek’s wet bench station utilizes Kaijo’s standard megasonic generator which operates at 950 kHz. Frequency ranges of 200 kHz, 430 kHz, 750 kHz as well as 2 MHz are also available for cleaning applications that require a more or less robust cleaning action. There are three versions of Megasonic cleaning systems available which provide power levels of 600, 900 or 1200 Watts.

Modutek incorporates the use of Megasonic cleaning into their wet benches using either indirect or direct bath designs. Indirect Megasonic cleaning can operate at temperatures of up to 140 degrees centigrade while the direct design places a Teflon-coated transducer directly into the tank and can operate at temperatures up to 70 degrees centigrade. Both design options provide optimal sub micron particle removal without causing cavitation damage to the silicon wafers at the standard 950 kHz frequency.

Process engineers at semiconductor manufacturing fabs have effectively used Modutek’s wet benches stations that incorporate the use of megasonic cleaning to improve semiconductor device yields. The time needed for cleaning wafers is reduced while cleaning effectiveness is higher with less chemical consumption. The use of Megasonic technology has improved the removal of small sub-micron contaminants and has reduced wafer defects to produce better quality semiconductor devices. If you need to improve wafer manufacturing processes and device yields call Modutek for a free consultation or quote at 866-803-1533 or email [email protected].

Why Particle Removal is Essential in Silicon Wafer Cleaning

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During silicon wafer processing, impurities and particles are deposited on wafer surfaces or are left over from previous process steps. Such particles can cause defects in the final semiconductor product. With the reduced size of today’s silicon wafer microstructures, even the tiniest particles can block etching and affect the diffusion processes. The result appears in the final semiconductor circuit as either as a defect or reduce quality and life expectancy of the product. As a result, the focus of many wafer cleaning operations is to leave the silicon wafer surface intact but free of contaminating particles.

How Particles are Removed from Silicon Wafer Surfaces

The removal of particles can be difficult because they often have a chemical or electrostatic affinity for the silicon surface. They are attracted to the silicon wafer because of electrostatic charges and specific mechanisms have to be used to dislodge and remove them. The smaller the particle, the more such attraction may play a role and the harder it is to remove every particle from the wafer.

Mechanisms to remove particles include silicon wafer cleaning with a chemical that reacts with the particles, cleaning with a solution that dissolves the particles or washing the particles from the wafer surface. In each case, a specific type of equipment is required and traditional standard processes can be used together with new technologies aimed at removing even the smallest particles.

Cleaning Processes

Many chemical processes used to clean silicon wafers have remained unchanged since they were first used 30 years ago. These methods use aggressive chemicals to remove contamination from the wafers, which are then rinsed with de-ionized water and dried. These methods remove most of the contaminants but are less effective in removing the smallest particles. Refined older methods and new technologies such as megasonic cleaning are now often used to complete the cleaning process.

Cleaning methods used at different stages of the silicon wafer fabrication process include the following:

  • The RCA clean process, often carried out in two steps called SC1 and SC2, prepares a wafer for further processing. SC1 cleans wafers with a mixture of ammonium hydroxide and hydrogen peroxide to remove organic residue. SC2 uses hydrochloric acid and hydrogen peroxide to remove metallic residues and particles.
  • The Piranha cleaning process removes large amounts of organic residue such as photoresist. It uses sulfuric acid and hydrogen peroxide in a particularly corrosive mixture that acts quickly but must be handled with care.
  • Megasonic cleaning dislodges particles and other contaminants using microscopic cavitation bubbles generated by a megasonic cleaning system. The bubbles form and collapse in time with the MHz sound waves, delivering a scrubbing action that overcomes particle attraction to the silicon wafer surface.
  • The Ozone cleaning process uses ozone to convert organic particles and contaminants to carbon dioxide. All organic traces on a wafer surface are completely removed, leaving the silicon wafer free from particles.

One of the most critical processes for silicon wafer cleaning is the pre-diffusion clean process that takes place just before the wafers are placed in the diffusion oven. Any of the above methods or a combination of cleaning methods can be used to ensure that wafers are free of particles and the diffusion will be even and consistent.

Equipment Used for Wafer Cleaning

Modutek’s wet bench technology supports all the above cleaning methods and can be provided within their manual, semi-automated or fully automatic systems. The company can offer equipment for traditional cleaning and for the new megasonic and ozone methods as well. All cleaning equipment is available in standard configurations but Modutek can also design custom products to meet the needs of any of their customers’ silicon wafer cleaning requirements. If you need highly reliable equipment to support your semiconductor manufacturing processes call Modutek for a free consultation or quote at 866-803-1533 or email [email protected].

 

Modutek at 2018 Semicon Conference in China

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2018 Semicon Conference ChinaModutek Corporation, a leading provider of wet bench stations and wet process equipment, will be at the Semicon Conference in Shanghai China from March 14-16, 2018 with their factory representative Laserwort Ltd.  They will be located in Hall N2 at booth 2431. Information about the Semicon Conference can be referenced at http://www.semiconchina.org/ and details on Modutek’s attendance at the conference can be referenced at: Modutek at Semicon Conference in China

Come by the Modutek /Laserwort booth to get information and answer any questions you have about using Wet Bench Process Stations for acid/base, solvent and ozone cleaning or photo resist strip.  In addition Modutek will also provide information about the benefits of their new IPA vapor dryer with the HF last process. Modutek serves customers around the world who require any type of wet processing equipment and builds chemical delivery systems for pharmaceutical, biochemical, solar and semiconductor manufacturing.

Additional details on some of Modutek’s products are listed below:

Single Chamber HF Last IPA Vapor Dryer

Benefits include:

  • Most drying cycles completed within 10 to 15 minutes
  • Very low consumption of IPA
  • No moving parts inside drying chamber eliminating wafer breakage
  • Eliminates watermarks
  • Drying technology can be designed into wet bench eliminating one transfer step

Features include:

  • Single drying chamber for DI water rinsing and IPA vapor drying
  • On board HF metering for precision mix ratios
  • Uses an in situ HF etch process with a rinse step before the IPA drying cycle
  • Filter bypass for contamination control with no cassette contact points
  • Easy to change IPA bottles
  • Handles all process sizes (standard wafer carriers to glass substrates)

 

Fully-automated Wet Bench Equipment

Benefits include:

  • In house customization to meet customer process requirements
  • Precise automated process execution and reliable repeatability
  • Full automation control with touch screen
  • Improved yield and reduced errors
  • SolidWorks Simulation software for accurate calculation of process parameters
  • All robotics and software design designed in house
  • Complete design, assembly and test at one location to meet your specifications

 

Semi-automated Wet Bench Equipment:

Benefits Include:

  • Automation control with touch screen
  • Servo motor automation
  • SolidWorks Flow Simulation software
  • SolidWorks Simulation Professional software
  • All robotics and software designed and developed in house
  • Complete design, assembly and test at one location to meet your specifications

 

Manual Wet Bench Equipment:

Benefits Include:

  • High end manual equipment at competitive pricing
  • Meets or exceeds all current safety standards
  • Low cost of ownership
  • Designed to meet any process requirements
  • Can accommodate custom designs and processes
  • Equipment designed for future expansion

 

All wet bench equipment supports the following applications:

  • KOH Etching
  • Quartz cleaning
  • Ozone Strip
  • Ozone Cleaning
  • SC1 & SC2 (RCA Clean)
  • Megasonic Cleaning
  • BOE (Buffered Oxide Etching)
  • MEMs processing
  • All solvent applications
  • Hot phosphoric (Nitride Etching)
  • SPM Cleaning
  • Precision Part Cleaning

Modutek has over 37 years of industry experience and expertise in developing and building wet bench stations and wet process equipment that provides highly reliable results for precision processes. They also provide world-class service, and customer support. Contact Modutek at 866-803-1533 or email [email protected] for a free quote or consultation to discuss your requirements.

 

The Benefits of Using Modutek’s Quartz Tube Cleaning Stations

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The semiconductor wafer is the substructure on which the circuitry of every computer chip is laid down. Semiconductor wafers are fabricated in high-tech foundries, and require a precise, ultra-clean operation. One of the most basic requirements of a semiconductor wafer operation: reliably clean quartz tubes. Quartz tube cleaning stations are required equipment at every semiconductor foundry.

Most have several units stationed at different parts of the manufacturing process, each one specifically tuned and adjusted to the requirements of specific applications. Since the quartz tube cleaning process requires the use of corrosive chemicals, it takes an involved manufacturer and installer of quartz tube cleaning stations to design and install custom units for specific client needs.

How do quartz tube cleaning stations help?

Quartz tubes being delicate articles, cleaning them can be risk-prone. The ideal quartz tube cleaning process, therefore, minimizes human handling at every stage. This is the reason automated quartz tube cleaning stations are essential at any semiconductor wafer foundry.

With Modutek’s quartz tube cleaning stations, the handling of tubes during the cleaning process is mostly avoided — cleaning stations are designed to keep quartz tubes in motion while they are etched, and powerful nozzles direct water spray at the quartz tubes to maximize coverage Custom-designed cleaning stations come with many other options that can be applied to specific needs. Automated processes and nitrogen-drying can help in specific parts of the manufacturing process, for instance.

What do quartz tube cleaning stations look like?

The quartz tube cleaning stations designed and fabricated by Modutek are built out of white polypropylene. The cleaning processes are controlled by systems that can be turned to manual or automated mode, and units can be customized to specific height levels to perfectly fit the processes to which they are to be applied. Workers at these stations are protected from the acid cycle with PVC safety shields, and other standard features include hand-sprayers for deionized water, and Teflon guns for nitrogen use.

Clients are presented with a wide array of choices comes to customization. The station can be constructed out of FM 4910, or can include a hot nitrogen drying process as needed, for example. The right kind of holding tanks, automated bottle washers and other features can be designed and applied where necessary, and quality certifications required by third parties are arranged for, as well.

Automation Where it’s Needed

Modutek’s quartz tube cleaning stations can be designed and customized with optional automation for process lines that need it. From automated program recipes to tube roller systems, every part of the process can be made more efficient with automation. The operator merely monitors and controls the process through information presented on a screen, and can control various functions remotely. From bottle washing to drying, every part of the process is remotely monitored.

Automated processes do not actually require operator intervention. Processes, once they are set off, can go through to completion without operator input. Manual functions, when they are necessary in certain processes, can be remotely controlled at any point.

A process design that is set up to help the operator test different cycle times, is one of the most important parts of a properly designed automated system. Modutek offers a well-designed process to aid in testing. Once the right times are discovered, they can be locked in place to prevent accidental change

Modutek’s quartz tube cleaning stations, whether manual and automatic, are fully designed in-house. In-house design expertise helps ensure superior performance in any installation. With ultra-cleanliness being a basic requirement of the semiconductor fabrication process, customization to individual process needs is an absolute necessity for effective design. Modutek’s close control of the design of these appliances helps make it happen. Clients find Modutek’s complete, end-to-end support immensely helpful in the design of their lines. Whatever the application, Modutek has the expertise to evaluate, assess, design and deliver turnkey solutions.

 

Advantages of HF-Last Etching and IPA Drying in One Chamber

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In the final stage of silicon wafer cleaning the silicon oxide layer has to be removed and the clean wafer dried without contamination. When wafers are removed from the HF etching process and transferred to a drying chamber, the extra handling increases the chances for wafers to pick up contaminating particles. Such particles cause errors in the further processing of the wafers and can result in final semiconductor products that are defective or of poor quality. Carrying out the final etching and the wafer drying in one chamber reduces the possibility of contamination and can result in better output quality. The latest field results from a customer using Modutek’s single chamber HF-last and IPA vapor dryer show a substantial reduction in particle counts on wafer substrates.

The Single Chamber Process

Modutek uses IPA vapor (Marangoni) drying in a free-standing unit with one drying chamber for DI water rinsing and drying. The IPA vapor is generated in a standard one gallon bottle and is introduced into the drying chamber through the top cover to ensure even distribution. IPA consumption is low but is still adequate to give surface tension drying across all wafers and substrates. The Marangoni drying technique results in wafers without any watermarks.

To allow single step etching and drying in one chamber, Modutek modified the IPA vapor dryer to include HF (hydrofluoric) acid injection before the start of the standard IPA vapor drying process. The HF acid injection is ratio controlled and provides an oxide etch down to bare silicon. Once etched, the wafers are rinsed to a controlled pH level. When the required pH level is reached, the IPA drying process begins without moving the wafers. The particle count on the wafers remains low.

Field Results

Modutek has supplied the new single chamber HF-last IPA dryer to customers and the first large scale results are now in. In the 0.3 to 5 micron range, fewer than 20 particles (adders) were added to the etched substrate after using the Modutek etching/drying combined system. These particle counts are substantially below those achieved using the previous process in this particular field trial. Semiconductor manufacturing facility managers and research center engineers can compare these results to particle counts resulting from their current process and may be able to achieve significant improvements using the Modutek equipment.

The number of microscopic particles on wafers is becoming more and more critical as micro-structures and electronic features become smaller. Where comparatively large conducting areas and physical structures can work well even when they contain a disruptive particle, particles in the way of smaller structures either result in defective semiconductor components or in components whose characteristics are not as specified.

Modutek’s single chamber technology lets semiconductor manufacturing facilities improve output performance and increase yield. The entire etching, rinsing and drying process took only about 15 to 20 minutes in this application. One customer is reviewing particle counts, yields and output quality throughout the entire operation because it is likely that the improved facility performance with the Modutek system can justify the cost of acquiring the new equipment.

How Modutek Can Help

Modutek has over 35 years of experience providing wet processing equipment to the semiconductor manufacturing industry. The company has the expertise to advise customers regarding their semiconductor processing needs and can customize their equipment to fit particular applications. Their state-of-the-art equipment has helped wet process facilities meet their production goals in the past and the new single chamber HF-last etch and IPA vapor dryer can now help customers improve overall production line performance and increase facility profitability.