Using KOH Etching for Batch Processing

Using KOH Etching for Batch ProcessingEtching baths with varying concentrations of potassium hydroxide (KOH) and controlled temperatures are used in creating microscopic structures on silicon wafers. Modutek can supply equipment such as PFA Teflon tanks, circulation and filtering systems and cassette handling equipment that supports KOH etching. The company designs and builds individualized systems for customers who want to use KOH etching and the resulting systems deliver accurate control, high repeatability, consistent performance and superior output quality.

The KOH Etching Process
The KOH etching process is well understood and is a preferred method for creating silicon wafer nano structures for semiconductor manufacturing and in research facilities. The process delivers controlled and uniform results with high precision and it is relatively safe.

The silicon surface is masked to allow etching and cavity creation in specific areas according to the layout of the final semiconductor product. The etch rate can be controlled by varying the concentration of KOH and the bath temperature. KOH etching is also impacted by the following:

  • The lattice planes of the crystalline silicon
  • Boron doping of the silicon
  • The presence of atomic defects in the silicon crystal
  • Natural impurities

Orienting the lattice planes in a particular direction can influence and control the direction of the etching and the shape of the cavities created in the silicon. Similarly, boron doping can be used to stop etching in a particular direction. Together with the mask, these factors permit the creation of cavities of the required shapes and orientations. Defects in the silicon crystal or natural impurities may reduce the quality of the final product and can result in defective items.

Advantages of KOH Etching
KOH etching provides excellent results and is used extensively because of the following advantages:

  • Safe and easy to handle
  • Rapid etching
  • Excellent reproducibility
  • Low cost
  • High precision when process variables are tightly controlled

Modutek can supply equipment that builds on the listed advantages to deliver corresponding benefits to the customer.

Modutek’s KOH Etching Process Equipment
Modutek’s wet bench technology supports KOH processing, and Modutek examines each request in detail before building the equipment for a particular application. This includes the KOH processing tank, the recirculating system and the silicon wafer handling. Sizes, capacities and control characteristics are adjusted for the customer’s requirements.

The systems supplied by Modutek use the latest technology to provide high accuracy and excellent output quality. Etch rates can be controlled precisely and etch uniformity is guaranteed. Even long etch times, such as up to 3 days, can be handled reliably and safely.

Modutek’s KOH processing tanks are PFA Teflon with all-Teflon fluid paths. The tanks are manufactured onsite using advanced PFA sheet welding techniques designed to minimize impurities and unwanted by-products. The tanks are available as static or as recirculating baths.

The static baths can be ambient temperature baths or temperature controlled from 30 to 100 degrees centigrade. The recirculating temperature controlled baths feature heat-up rates of 2 to 3 degrees centigrade per minute and a temperature control accuracy of plus/minus 0.5 degrees centigrade. The available semi automatic cassette handling reduces costs and increases reliability.

In each case Modutek makes sure that the equipment supplied fits into the existing or a new installation and is compatible with any other wet processing systems. Modutek’s specialists work to ensure the supplied equipment satisfies the customer’s requirements and meets or exceeds performance expectations.

Silicon Wafer Etching Processes for Wet Processing Applications

Silicon Wafer Etching Processes for Wet Processing ApplicationsThe manufacture of semiconductor components such as processors and integrated circuits relies heavily on the etching of silicon wafers with processes such as KOH etching to generate the required structures and connections. Modutek provides wet bench technology that can be used for a wide variety of these etching applications. Managers in charge of semiconductor manufacturing facilities, research centers or universities as well as process engineers working at these organizations can use wet bench equipment from Modutek to meet their silicon wafer etching needs.

KOH Etching

Etching silicon wafers with potassium hydroxide (KOH) is used to create microscopic structures in the silicon. The etch rate is impacted by the temperature of the etching bath, the concentration of KOH and the crystalline structure and impurities in the silicon. KOH etching is an inexpensive and repeatable process that etches rapidly. Modutek offers PFA Teflon tanks of their TFa or TT series for KOH etching applications.

Silicon Nitride Etch

Silicon nitride is used as a masking material in the fabrication of integrated circuits. It can be deposited on the silicon wafer as a thin film and is etched with hot phosphoric acid. The bath temperature is about 180 degrees Celsius, the boiling point of phosphoric acid. The Modutek series Nb nitride etch bath achieves precise temperature control by regulating the de-ionized water to phosphoric acid ratio. Modutek’s silicon nitride etch baths offer excellent repeatability, accurate process control and a high level of safety.

Piranha Etch

The piranha solution is made up of a mixture of sulfuric acid and hydrogen peroxide and is used to clean silicon wafers during the semiconductor manufacturing process. A common ratio used is 3 parts of concentrated sulfuric acid to one part of 30 percent hydrogen peroxide. The solution cleans organic compounds from substrates and oxidizes most metals. It is often used to clean photoresist from silicon wafers. Modutek can evaluate a customer’s silicon wafer cleaning requirements and propose suitable solutions from its extensive line of wet processing equipment.

Metal Etch

The conductors linking the microscopic electronic structures on a silicon wafer must be metallic to conduct the electric signals. Metals such as aluminum, copper and gold are deposited on the silicon wafer and must be etched. Etching metals can be challenging and effective etching depends on selecting the right chemicals and process.

For example, the Modutek vacuum metal etcher is designed for precise wet etching of aluminum layers. The process takes place under vacuum because the chemical reaction creates hydrogen bubbles that interfere with etching precision. In the vacuum, the bubbles are immediately removed by an evacuating pump. Modutek’s wet process equipment can use a variety of etchants to etch different metals.

Gallium Arsenide (GaAs) Etch

Gallium Arsenide is a semiconductor used in the manufacture of integrated circuits and other electric and electronic devices. It is etched with solutions containing hydrogen peroxide, usually in combination with sulfuric, hydrochloric or phosphoric acids. Modutek’s wet process solutions can handle such etching chemicals at lower cost than dry etching.

Modutek Wet Bench Solutions

As a premier provider of semiconductor manufacturing equipment for over 35 years, Modutek can offer wet processing equipment for a wide variety of semiconductor etching and cleaning applications. Modutek’s wet bench technology delivers reliable, repeatable results safely and accurately. The company can help customers in industry and research find solutions to their semiconductor manufacturing needs. For a free quote or consultation on selecting the right equipment for your silicon wafer etching process, contact Modutek at 866-803-1533 or email [email protected].

Modutek At Semicon Conference in China

Modutek At Semicon Conference in ChinaModutek, a leading provider of leading-edge wet benches and wet process equipment, will have a factory representative at the Semicon Conference in Shanghai China from March 15-17, 2016. Modutek will be with their China Rep Laserwort located in Hall N3 at booth 3401. 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

Stop by the Modutek /Laserwort booth to get information and answer any questions you have about Automated, Semi-Automated and Manual Wet Process Stations used for acid/base, solvent and ozone cleaning or photo resist strip. Modutek also provides IPA vapor drying and Megasonic cleaning equipment to support your manufacturing applications. In addition environmentally friendly acid neutralization systems and air scrubbers are available with all their equipment.

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

  • Fully-automated Wet Bench Equipment
    • Benefits include:
      • Full automation control with touch screen
      • SolidWorks Simulation Professional software
      • SolidWorks Flow Simulation software
      • Servo motor automation
      • All robotics and software designed in house
      • Complete design, assembly and test done according to your specifications
  • Semi-automated Wet Bench Equipment:
    • Benefits include:
      • Automation control with touch screen
      • SolidWorks Simulation Professional software
      • SolidWorks Flow Simulation software
      • Servo motor automation
      • All robotics and software designed in house
      • Complete design, assembly and test done according to your specifications
  • Manual Wet Bench Equipment:
    • Benefits include:
      • High end manual equipment at competitive pricing
      • Meets or exceeds all current safety standards
      • Designed to meet any process requirements
      • Can accommodate custom designs and processes
      • Low cost of ownership
      • Equipment designed for future expansion

Our fully-automated, semi-automated and manual wet bench equipment supports the following applications:

  • KOH Etching
  • Quartz cleaning
  • Ozone Etching
  • Ozone Cleaning
  • SC1 & SC2 featuring Megasonic Cleaning
  • BOE (Buffered Oxide Etching)
  • MEMs processing
  • Plating
  • All solvent applications
  • Hot phosphoric (Nitride Etching)
  • SPM Cleaning
  • Precision Part Cleaning
  • IPA Vapor Dryer
    • Benefits include:
      • Very low IPA consumption
      • No moving parts inside drying chamber which eliminates wafer breakage
      • Most drying cycles completed within 10-15 minutes
      • No watermarks
      • Drying technology can be easily designed into your wet bench eliminating one transfer step
    • The IPA Vapor Dryer supports the following applications:
      • Ozone Cleaning
      • Wafer Drying

Modutek has over 35 years of experience 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. Call 866-803-1533 or email [email protected] for a free quote or consultation to discuss your requirements.

Improvements to the Silicon Wet Etching Process

Improvements to the Silicon Wet Etching ProcessAs a result of improvements in design, and materials, the silicon wet etching process can produce better wafer yields with reduced defects. Modutek provides equipment engineered to incorporate such improvements that are designed for reliability, safety and low cost of ownership. The company’s wet etching products include features that offer specific advantages and deliver improved results. Process engineers and fabrication facility managers can order equipment customized to meet their needs and to ensure they receive the process improvements they expect.

Modutek’s QFa Series High Temperature Recirculating Quartz Baths and the Qa Series Constant Temperature Quartz Baths are designed to set the quality standard in quartz baths. Used for etching, stripping and heating, the baths feature fast, even heating to improve process yield and minimize damage from runaway temperatures. The high quality internally flame polished virgin fused quartz process vessels reduce downtime and increase reliability due to longer vessel life.

Although Modutek’s Teflon tanks come in standard carrier sizes, the company will build custom sizes to match any requirement. Tank configurations are Temperature Controlled Recirculating Baths, Temperature Controlled Static Baths and Teflon Ambient Baths. Inline heating or immersion heating are available. Modutek can help design the optimal configuration for both new as well as existing systems you may already have.

Modutek’s silicon nitride etch baths deliver excellent process control while retaining flexibility in installation and operation. The control system monitors the temperature of the bath to determine when adding de-ionized water is required to maintain the acid to water ratio. As water is lost to evaporation, the boiling point of the bath increases and the control system adds small amounts of water to the boiling liquid, ensuring that the water mixes in immediately. This method tightly controls the boiling of the chemicals and avoids “bumping.” The availability of remote metering means that the product is easy to install and Modutek can help find the best solution for any process station.

Modutek’s line of Quick Dump Rinsers can increase process efficiency by reducing rinse times and DI water consumption. The Rinsers feature state-of-the-art engineering to eliminate particle entrapment and minimize rinsing times. Dual overhead spray manifolds, a contoured vessel design and a large machined dump door ensure efficient and rapid operation.

For facilities that could benefit from using KOH etching, Modutek offers customized solutions manufactured according to customer specifications. KOH etching is a repeatable process that delivers fast etching at a low cost. Modutek’s solutions use the company’s Teflon tanks with advanced welding techniques and all-PFA material. The products can be designed to particular specifications or to be compatible with your existing wet bench equipment. Once the wet etching process is established, continual adjustments are not necessary. Modutek can integrate the new products into an existing line to deliver process improvements and increased efficiency.

Making use of improved designs or higher quality materials can generate substantial benefits from reduced costs and better throughput. The increased ability to manufacture customized products that are optimized for a particular application can further improve silicon wet etching results. For any questions about silicon wet etching products or for help selecting the right manufacturing equipment for your requirements call Modutek at 866-803-1533.

Wet Processing Equipment Applications

Wet Processing Equipment ApplicationsModutek provides a complete line of silicon processing solutions with state-of-the-art wet processing equipment designed to deliver high quality output at a low total cost of ownership. Applications include wafer etching, cleaning, drying, stripping and metal etching. Specific solutions include KOH etch and nitride etch. State-of-the-art design and engineering ensures that equipment is reliable, safe and low-maintenance.

The rotary wafer etching system can etch, clean, reclaim, develop and strip semiconductor wafers and substrates. It features a dual tank design with a transfer between tanks for etching and cleaning or rinsing. A carrier assembly holds the wafer boats and takes up to 50 six-inch or 25 eight-inch wafers at a time. When the operator closes the fume door and presses the start button, the carrier assembly carries out a continuous rotational agitation in the chemical tank for a pre-set time. The assembly then automatically transfers the wafers to the rinse tank in less than three seconds. After the Quench-Quick Dump-Overflow rinse cycles, the wafers can be moved to the drying unit.

The system can be programmed with up to five process recipes and a touch screen controller displays a summary of the recipe and the process. Axial rotation of the wafers at up to 80 rpm ensures adequate agitation for consistent results. The system is flexible enough to handle different semiconductor processing applications and can carry out automatic batch processing.

Modutek’s vacuum metal etcher is designed for precision etching of aluminum layers on semiconductor wafers. The fully automated unit etches aluminum in a vacuum to eliminate hydrogen bubbles that interfere with the etching and produce “snow” and bridging on the etched wafers. At the beginning of a cycle, the unit evacuates the plenum, drawing acid into the etch tank. Etching continues until the preset time is elapsed or the end-point detector senses that lines have been etched through the aluminum layer. When etching is complete, the acid drains back into the acid reservoir and nozzles spray deionized water over the wafers. The metal etcher is characterized by a fast throughput and a high yield.

Modutek’s IPA Vapor Dryer provides a way to clean dry wafers without water spots. The unit can introduce ozone into the drying chamber to eliminate organic impurities. Most drying cycles take only 10 to 15 minutes. As low-cost drying solution, Modutek can custom design their IPA vapor dryers to meet your specific requirements and application.

In addition to equipment that can be used for a variety of semiconductor processing, Modutek offers specific solutions such as KOH etching and nitride etching. For KOH etching, Modutek uses an individualized approach that produces solutions for specific customer applications with the company’s Teflon tanks. The tanks are all-PFA material and sheets are welded using advanced techniques designed to reduce impurities. Modutek KOH etching solutions are designed to work with a customer’s existing wet bench equipment.

For nitride etching, Modutek provides a new Nb series Silicon Nitride Etch Bath. The system features a dual system that monitors the chemical boiling while ensuring tight control of the nitride etching process. As a result, the system provides unparalleled control of the nitride etch process and uniformity while achieving elevated levels of safety and reliability.

Modutek’s wet processing equipment is designed to meet the application needs of any semiconductor fabrication or research facility, either with standard products or with custom-designed solutions. Call Modutek at 866-803-1533 for any questions you have about wet processing equipment or if you need help in choosing the right equipment for your specific requirements.

Using the KOH Etching Process with Modutek’s Teflon Tanks

Potassium hydroxide-KOH etching is an efficient chemical process that allows for precise impressions to be made within a body of silicon. The process uses DI (deionized) water in combination with heavy alkalinity (pH levels greater than 12); the solution is then thermally adjusted for the appropriate degree of etching needed. This process allows for greater precision than other forms of etching when it comes to manufacturing silicon wafers.

What Are the Benefits of Using KOH Etching?

The precision KOH etching grants is very beneficial to the product’s outcome. Due to its chemical composure and procedural approach, dry etching is more apt to create physical flaws; it also can make for a more hazardous environment, as it risks the exposure of toxic — even explosive — chemicals.

KOH etching, on the other hand, is almost entirely aquatic. The liquids for the etching process are contained within Modutek’s own Teflon Tanks, meaning that exposure to hazardous chemicals is drastically reduced to create a safe environment for manufacturing. The structuring behind the process also means that it can easily be set up for repeat manufacturing; the resources required for the etching are more stable and affordable, meaning that clients can duplicate their etchings at a much more feasible rate.

How Do Teflon Tanks Bolster the KOH Etching Process?

Modutek’s Teflon Tanks are designed with the foresight to emphasize the maximum potential KOH etching can provide. Furthermore, each Teflon Tank is fashioned to cater to the specific needs of the client, regardless of unorthodoxy. In unison with wet bench equipment, these Teflon Tanks greatly reduce the impurities other methods of etching may establish, providing you with a more reliable and consistent output every time.

The Teflon Tanks can be thermally adjusted to operate between 30 — 100º C (86 — 212º F), and on average can heat up at a rate of 2 — 3º C per minute, though smaller or larger tanks may have varying thermal increase rates. Thermal output can be mustered either from inline Teflon heating, or from submersion within an overflow bank for each type of Teflon Tank. Each tank is also fitted with cooling coils that can quickly reduce the solution’s temperature.

There are two types of Teflon Tanks that support KOH etching: Temperature Controlled Re-circulating Baths (TFa Series), and Temperature Controlled Static Baths (TI Series). These two series of Teflon Tanks are designed with overlapping covers to minimize the loss of water during the etching process; they also boast the ability to eliminate concentration deficiency.

Because Modutek designs their Teflon Tanks with the client’s specifications in mind, the customization each tank receives is advantageous to the desired end result. Dual heating methods produce a quick, balanced aid to water-based etching. Drains and valves can be installed into the tanks for safe and easy clean-up. Remote timers, controllers, or even a data interface can be equipped to make a simple process even simpler.

When compared to other forms of etching (whether wet or dry), Modutek’s support of KOH etching produces more precise and affordable results in a safer and more expeditious work environment. Teflon Tanks can be produced individually or en masse depending on the output the client is in need of. Each tank can also be fitted with a number of practical options that can improve the etching process dramatically.

No client should work with an environment or product that diminishes the quality of their manufacturing process; customization leads the way for an innovative and effective product. Modutek’s support of KOH etching in their catalytic Teflon Tanks will provide exceptional results for clients that use this process.

How Modutek’s Wafer Fabrication Equipment Provides Optimum Results

How Modutek's Wafer Fabrication Equipment Provides Optimum ResultsIn 1980, Modutek began manufacturing wet-processing and wafer fabrication equipment for the semi-conductor industry. Working with industry leaders Modutek has stayed focused to their roots by providing high-quality clean room equipment for advanced technical applications. Today, their wafer fabrication equipment and wet bench stations are used in a variety of applications from commercial to academic.

Achieving optimum results with Modutek’s Wet Processing Stations.

Modutek’s wet processing stations provide high quality and optimum results for your manufacturing process. Available in fully-automatic, semi-automatic, and manual benches. All bring unique advantages for your process requirements.

Wet Bench Manual Stations: Offered in a cost effective package, manual stations will support acid and solvent applications. This is offered with various options including a host of safety features without the need for advanced robotics.

Wet Bench Semi-Automatic Stations: Ideal for professional, academic and business applications, Modutek’s Semi-Automatic stations provide a large variety of customizations while remaining competitively priced. Our stations are ideal at continually producing uniform steps for technical work.

Wet Bench Fully-Automatic Stations: Packaged with in-house software, fully automatic robotics and top-of-the line features, Modutek’s fully-automatic stations are the most advanced option for optimal etch rates.

Built exclusively for your needs

Modutek’s wet benches can be customized to handle a host of solvents and applications. In addition to handling all solvent applications, wet benches can be adapted to the following processes:

  • KOH Etching
  • Ozone Etching
  • Ozone Cleaning
  • SC1 & SC2 featuring Megasonic Cleaning
  • Precision Part Cleaning
  • BOE (Buffered Oxide Etching)
  • SPM Cleaning
  • Plating
  • Quartz cleaning
  • Hot phosphoric (Nitride Etching)

Customized with state-of-the-art features

Modutek’s units are use in leading medical, solar, and academic labs. Their popularity is founded from their units’ ability to produce uniform results while exceeding current safety requirements. Additional features may be added to assist in achieving optimal results including:

  • FM4910 (PVC-C) material of construction
  • Rear access design
  • Third party certification for NFPA 70 & 70
  • Semi standard, CE mark and NEC certification available
  • Seismic zone 4 structural certification
  • Fan Filter Units (HEPA)
  • Lift station designed into bench
  • Dedicated drains to carboy with DOT containment
  • Overhead deck lighting
  • Light tower (3-color)
  • Counter balance safety shields

No matter your need or application Modutek’s experienced engineers and technicians will customize, build and test your unit to meet your requirements to provide optimal results. Modutek provides world-class service, set-up and customer support. Their Wet Benches and Wet Process equipment  provide high reliable results for precision processes. Contact them by calling 866-803-1533 or by email from the site.

What Modutek’s Dry to Dry Etching Process Equipment Provides

What Modutek’s Dry to Dry Etching Process Equipment ProvidesDry to Dry base / acid wet process from Modutek Corporation is fully automated equipment which is available in many different configurations to serve your requirements for wet process. Modutek’s engineering team put a lot of effort into designing the most effective equipment to support a dry to dry etching process  for your application. All the process sizes are handled from wafer carriers which are standard silicon wafer, glass substrates to glass solar panels of 30” X 60”.

All cleaning, wet process or etching components are designed and built in-house and provides you complete turnkey support. Station of dry to dry utilizes the MVD (Modutek Vapor Dryer) Series IPA Vapor Dryer. This allows you to proceed to the step in processing without using a separate tool in drying. Therefore it eliminates the need of transfer time, and this is a very effective way of improving both throughput and yield. The advanced software will increase your yield, improve your throughput and etch rate. The entire robotic system is completely designed, assembled and quality tested at San Jose, CA with the professionals from Modutek Corporation. All quality procedures use DI water for testing.

This wet process equipment has several features which are useful in your day to day applications. The features give it several advantages that will offer various benefits to you.

 Standard features:

  • Has a IPA Vapor Dryer on board (MDV Series)
  • White polypropylene construction
  • Emergency Power Off (EPO) is equipped with all safety locks
  • Available in multiple sizes and lengths to cater to your specific needs
  • Stations are all wired according to NFPA 70 and 79
  • Every wet process tank has 1” lip exhaust
  • PLC has  touch screen/ graphic user interface (GUI)
  • Servo motor motors has encoder feed back
  • One year warranty (all parts)
  • Leg levelers and casters
  • DI water manifold continuously flow
  • Hand spray for DI water and Teflon N2 gun
  • PVC safety shields
  • Photohelic interlocked to EPO
  • 2-copies of manual paper and a complete paperless set

Benefits include:

  • On board drying tool included
  • Long period of continuous operation (over 35 years)
  • All designing, assembly and testing is done at a single location
  • Software Design includes SolidWorks Simulation Professional and SolidWorks Flow Simulation
  • No outsourcing for either software or robotic design

Applications:

  • Diffusion Clean
  • Ozone Etching
  • Ozone Cleaning
  • KOH Etching
  • Buffered Oxide Etching (BOE)
  • Silicon Nitride Etch
  • SPM Clean
  • SC1 and SC2 containing Megasonic Energy

Optional Ozone Feature (Dry Zone)

The DryZone is a patented revolutionary new solvent gradient dryer. It exceeds the most vigorous total organic carbon (TOC) or volatile organic carbon (VOC) environmental concerns.

Silicon substrates are first rinsed in deionized water to remove any water inorganic impurities. After rinsing, the substrates enter a solvent chamber to develop a boundary layer, which will remove organic impurities. The substrates are then processed through an ozone chamber, either with or without ultraviolet light exposure, to convert all traces of organic materials into carbon dioxide gas. The substrate surfaces are then free from moisture, trace organics, and other particles. The substrate surfaces are stable hydrophilic surfaces. For silicon wafers, the surface is Si-O terminated. If hydrophobic surfaces are needed, a short 10 second post ozone conversion step renders silicon wafers Si-H terminated.

The dryer has no detectable VOC’s in the exhaust, and supports green chemistry initiatives, unlike isopropyl alcohol consuming dryers. Since the dryer uses reactive chemistries, it is more than just particle neutral, it is particle reducing!

Summary

The features, benefits, and applications discussed above say it all. Modutek’s engineering team designs the most effective etching or cleaning equipment needed for your application. If you have any questions or want to get a quote call us at 866-803-1533.

Using Modutek’s Teflon Tanks with KOH and TMAH Etching Processes

Using Modutek's Teflon Tanks wModutek’s TFa and TI series PFA Teflon Tanks, along with our other wet bench equipment, fully support KOH etching (Potassium Hydroxide) and TMAH etching (Tetramethylammonium hydroxide)processes.  Our Teflon Tanks are designed together with other wet bench equipment to decrease impurities and unwanted byproducts due to advanced welding techniques with PFA sheet material. Continual adjustments to the Si etching process are not necessary after the initial process has been established.  We construct all our Teflon Tanks and related equipment per individual customer specifications, and we routinely design products that are compatible with a customer’s existing wet bench equipment.

Modutek’s Teflon Tanks have an operating temperature range from 30 – 100º C, with a process temperature control of ± 0.5º C and a heat-up rate from 2-3º C per minute (depending on the size of system).  Our modular design allows for new installation or upgrades into any wet etching station configuration.

Teflon® tank configurations that support KOH and TMAH Etching:

  1. Temperature Controlled Re-circulating Baths (TFa Series)
  2. Temperature Controlled Static Baths (TI Series)

Teflon Tank design features:

  • Manual cover with overlapping seal
  • Minimizes water lost
  • No concentration deficiency over long etch time

Heat source options include: 

  1. Teflon® inline heating
  2. Immersion heating in overflow weir for TFa Series and main tank for TI Series

Static KOH etching bath with condensing coilsCustom Teflon® Tanks and Additional Options:

  • Custom size Teflon® tanks can also be built to match any size (no limitations)
  • Bottom drain features
  • Magnetic stirrer for agitation (TI and TT series)
  • Water condensing refluxor system available on all baths
  • Auto lid feature
  • DI water or IPA spiking system available

Benefits of Teflon Tanks:

  • Modular design
  • Two available heat sources
  • All Teflon® fluid path
  • Process temperature control of ± 0.5º C
  • Process etch uniformity wafer to wafer <2%
  • In house heater maintenance and repair
  • 360 degree overflow filtration
  • Uniform heating throughout the bath

KOH etching tank with condensing coils and semi auto robotModutek provides world-class service, installation and support for all our Teflon Tanks and related wet bench equipment. We provide quality products and services that focus on reliability, precision, throughput, usability and up-time. For more information contact us by calling 866-803-1533 or by email from our site.

Silicon Wet Etching Using Modutek’s Nitrite Etch Bath

Silicon Wet Etching Using Modutek’s Nitrite Etch Bath

Silicon Wet Etching Using Modutek’s Nitrite Etch Bath

Modutek has been designing and manufacturing Silicon Wet Etching components and related equipment for over 30 years. Their more recent Nitrite Etch Bath products, including the “Nb” series, is an upgrade to their “Na” series. The Silicon Nitride Etch Bath has been designed and engineered to provide unparalleled process control. You can also expect flexibility and safety as key components of these systems.

Part of what makes the Nb Series silicon nitride etch bath stand out is its two-tiered diagnostic system. This allows the user of the system to monitor the temperature at the same time as it maintains the acid-to-water ratio through supplemented D.I. water. This new metering system makes the Nb easier to install. It also allows for service in existing process stations or in new ones.

Some of the benefits of the Silicon Wet Etching system include, but are not limited to, the following:

  • Controlled Nitride Etching
  • Nitride Etch Uniformity
  • Remote DI water metering system
  • Controls chemicals boiling (no “bumping”)

The silicon nitride etches function in a combination fluid – 85% phosphoric acid (H3PO4) and 15% DI water. These fluids boil at 160°C. Since the water will boil off some of the solution as steam, the NbSeries silicon nitride etch bath includes a refluxor which cools the condenser to cause the steam to condensate back to water which maintains the solution. Please be aware, the condensers are not 100% efficient, which will make it necessary to add water to the solution periodically.

Generally, it is discouraged to add water to acid, but it is required in this case. We have determined some safe ways to do this. For instance, if the acid rapidly agitates or boils, you can add a small amount of water which mixes right away. This poses no safety issues. When the water is added to non-boiling acid, the water sits on top of the acid. More water is added to the top layer of the acid. The water will mix as the heat absorbed by the water makes it boil. The water mixes thoroughly with the acid and the correct reaction occurs.

A basic chemistry rules states, “The temperature of a solution cannot rise above its boiling point, except under special circumstances.” The heater on our system does not have to be controlled the way it is required on other systems. If the heater switch is on, the heater is on. By choosing not to regulate the heater, the heat solution is allowed to boil regardless of the concentration. The system keeps it boiling while water is added to adjust the concentration, which remains at the upper set point.

The Silicon Wet Etching and Nitrite Etch Bath systems also include the following features:

  • Etched-foil resistance heater
  • PVDF or Teflon reflluxor with safety cover
  • Vapor thermocouple
  • Uniformity heat transfer
  • Ease of installation and repair for new or existing wet station configurations

System Specifications include the following:

  • Application: Silicon Nitride Etch
  • Operating temperature range: 30 – 180º C
  • Chemical usage: H20, H3PO4
  • Heat-up rate: 2-3 º C per minute (rate affected by size of system)
  • Process temperature control: ± 0.5º C
  • Vapor thermocouple for chemical boiling control
  • PVDF refluxor with Teflon® cooling coils
  • One year warranty

Companies that need additional features may consider any of the following options. Modutek will work with you to design the Silicon Wet Etching system that best meets your company’s needs. Options include, but are not limited to:

  • Teflon® gravity drain system
  • Auto cover which is pneumatically actuated
  • Remote operation timer switches
  • Aspirator valve system
  • Model C1815a process controller/timer
  • RS232 Interface

To learn more about the Silicon Wet Etching products sold by Modutek Corporation, or to learn how our products can be redesigned to work with your Nitride Etch Baths or Quartz Baths and Sub Ambient Systems (BOE), contact us at 866-803-1533.