How Chemical Delivery Systems Are Designed to Meet Customer Requirements

how-chemical-delivery-systems-are-designed-to-meet-customer-requirements2Many industrial activities require the supply of a variety of chemicals for their manufacturing or production processes. Because the industrial process may include special procedures and the use of specific chemicals, chemical delivery systems often have to be custom-designed to exactly meet the needs of a facility. Typical custom requirements deal with the quantities of chemicals required, how often chemicals have to be changed, how accurate the delivery or the mix has to be and the repeatability of a specific process. Safe handling is an important issue when the chemicals delivered are hazardous, as is safe neutralization and safe disposal. Customized systems can address each of these issues and ensure that the critical requirements are satisfied while leaving out unimportant features for a cost-effective solution.

Delivery Volumes

The quantities of chemicals used greatly impacts the design of the chemical delivery system. Large totes remote from the process can continuously deliver large volumes over extended periods while local drums and tanks can deliver smaller volumes but can be changed when the process requires a different chemical or when a new production process is started. In each case, load or level sensing has to be available so production personnel can plan the required chemical delivery. Software allows operating personnel to predict flows and requirements so adequate supplies are available.

Precision and Repeatability

Different industrial processes have different requirements for precision. For example, research projects often have to record exactly what chemicals were used and their precise quantity. Some semiconductor manufacturing processes also require high precision but others don’t. Precision is linked to repeatability. If a process has to run exactly the same way each time, the level of precision for chemical delivery has to be the same for each run.

Custom design can guarantee that the levels of precision and repeatability required for a process can be achieved, but such features are expensive. Customization means critical requirements are met but if high precision is not required, costs are reduced to cover what is essential for the process.

Safe Handling and Disposal

Customization is especially important for safety because each chemical has its own hazards and each process presents different dangers. Customized chemical delivery systems provide an additional level of safety to employees in the handling the chemicals and operating the delivery systems for specialized applications. Custom designs look at measures such as double-walled containment, corrosion-resistant fluid paths and leak detection for safe handling. Neutralization and disposal requires a customized approach due to the different ways chemicals are used but also because of the different regulations for safe chemical disposal.

Custom Chemical Delivery Solutions from Modutek

Modutek has the experience, the product line and the customization capabilities to satisfy specific customer needs and deliver high-quality, reliable and safe chemical delivery systems. The company designs and assembles all systems in house at their factory in San Jose, California. Because of the presence of in-house expertise for all important subsystems including the chemical delivery software, Modutek can respond exactly to the customization requirements of each manufacturing or production facility and deliver custom solutions that respond to customer needs.

From tote, drum and tank storage possibilities through systems with high precision capabilities, Modutek can deliver the storage and repeatability features needed. The SolidWorks Simulation Professional and SolidWorks Flow Simulation software lets customers calculate precise mix and flow volumes. All chemical delivery systems are characterized by high levels of operator safety and special regulatory requirements for the disposal of toxic chemicals can be incorporated into the custom design as needed. With Modutek’s chemical delivery system designs, customers can be sure they are getting the systems they need. For a free quote or consultation contact Modutek at 866-803-1533 or email [email protected].

How Robotics Have Revolutionized Semiconductor Manufacturing

The automation over the last 25 years of wet bench stations used for semiconductor manufacturing has resulted in more efficient production and an increase in output quality. When the handling and mixing of the chemicals, the handling of the silicon wafers and the timing of the process steps were carried out manually, mistakes could result in defective products. Semiconductor equipment manufacturers have developed automation that has resulted in improved yields and less waste.

Modutek has been on the forefront of developing robotics and process control software that allows fully automatic or semiautomatic processing of silicon wafers. In this way, the entire semiconductor manufacturing process is controlled accurately and reliably. Chemical quantities and process timing are precise, process parameters are reproducible, and material handling is safe. Contamination is reduced with robotic wafer handling. For all these reasons, adding robotics to a wet bench processing line is a cost-effective solution for better facility performance.

Modutek’s Leadership in Wet Bench Robotics

During the company’s history of making wet process equipment, Modutek has focused on the integration of the latest technology in-house and with its own team of specialists. Founded in 1980, Modutek manufactured components such as quartz heated baths, nitride etch baths and rinsing systems. In 2002, Modutek acquired Sysmax Inc. with its advanced automation technology and from there developed its own robotics.

Advances in robotics have allowed Modutek and other semiconductor equipment manufacturers to offer semi-automated and fully automated stations. These wet benches and chemical stations can control the whole semiconductor manufacturing process with no or limited operator intervention. Both fully automated and semi-automated stations produce excellent process uniformity with semi-automated stations and robotics available at a lower cost if full automation is not required.

A key Modutek advantage for this type of equipment is that all process control software and robotics are designed and assembled in-house. The team working in the company’s San Jose, California manufacturing facility carry out all development work for both the SolidWorks Simulation Professional and SolidWorks Flow Simulation software and for the associated robotics. All silicon wafer fabrication equipment is also tested in-house using de-ionized water. As a result, Modutek can offer unparalleled support and customization services.

Advantages and Benefits

The primary motivators for installing fully automated wafer fabrication equipment are to reduce costs and improve output quality. Elimination of human error and increased precision of chemical use means less waste and high-quality products.

Modutek’s SolidWorks Simulation Professional and SolidWorks Flow Simulation software can calculate correct dosages and track chemical usage. With tighter environmental regulations, efficient chemical use not only reduces costs directly but also makes environmental compliance easier and less costly. When the composition of chemical baths is tightly controlled, the etch rate or wafer cleaning is predictable and consistent.

Automatic chemical delivery is not only more reliable than a manual procedure – it is also safer. Spills of hazardous or corrosive chemicals are less likely, and employee safety is increased.

Robotic handling of wafers can reduce contamination and deliver cleaner wafers for subsequent processing steps. The reduced size of features in semiconductor microstructures means that a single particle can block etching of a key feature or impact doping in a critical part of the semiconductor component. It is vital to keep contamination of wafers to a minimum, and robotic handling of wafers reduces the sources of particle contamination.

While some semiconductor manufacturing applications can be automated with standard solutions, in many cases the particular needs of a specific customer can require a degree of customization of the robotics and the process control software. Because Modutek does its own robotics and software design, developing custom applications is never a problem. Modutek’s team knows exactly how each part of the automated systems work and how to make the necessary adjustments.

With Modutek’s more than 35 years of experience, the company continues to promote innovation in robotics for semiconductor manufacturing. Robotics has made the wafer fabrication process more efficient, more predictable and safer. With its complete line of automated equipment, Modutek continues to bring these benefits to customers. For a free consultation or quote contact call 866-803-1533 or email [email protected]

How Megasonic Cleaners Improve Silicon Wafer Manufacturing

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 Teflon Tanks Are Used with the KOH Etching Process

KOH etching is a preferred silicon wafer fabrication method because it works rapidly and reliably while handling of the chemicals is relatively safe. The process relies on a contamination-free environment and uses the temperature and KOH concentration to control the etching speed. Teflon tanks are used in this process because the Teflon is stable and doesn’t degrade. The KOH etching process controls allow accurate and repeatable temperature control for reliable fabrication results and high-quality production. KOH etching in Teflon tanks with temperature control is an excellent process for silicon wafer nanostructure fabrication in both manufacturing facilities and research environments.

How KOH Etching Works

KOH or potassium hydroxide etches silicon quickly and at a constant rate that depends on the concentration of the solution and the temperature of the liquid. In addition to these controllable variables, silicon etching is influenced by the crystal planes of the silicon and the doping concentration. These factors can be used to direct etching in certain directions and to stop etching at given points. The result is that KOH etching can produce the precise nanostructures needed as long as the crystal planes and doping are used correctly.

The controllable variables have to be kept tightly to set values and variations have to be minimized. Important factors are the maintenance of the KOH solution at the desired concentration and temperature. The Teflon tanks have to be designed to support the consistent and accurate etching necessary for defect-free wafer fabrication.

Modutek Teflon Tank Features

Modutek Teflon tanks are designed to support KOH etching leading to wafer fabrication of the highest quality. The temperature-controlled tanks are available in re-circulating and static versions and come in standard sizes for single or double carrier capacities as well as in custom sizes when required. The re-circulating tanks have an all-Teflon fluid path, and in the available custom configurations, are easy to integrate into existing fabrication lines.

Modutek Teflon tanks eliminate contamination from the tanks or fluid paths by ensuring the KOH solution only comes into contact with Teflon, which in unaffected by the corrosive chemical. In addition, Teflon welding for the tanks is carried out with advanced PFA sheet welding techniques that reduce impurities and by-products. The result is that the KOH solution stays pure.

A key element of the KOH etching process control is the initial concentration of the KOH solution and keeping it constant throughout the process step. Modutek Teflon tanks have sealed lids that minimize water loss, even during lengthy etching. Water condensing systems and de-ionized water spiking systems are available if the application requires it.

The other variable affecting the etch rate is the temperature of the KOH solution. Modutek tanks have either inline heating or immersion heating in the overflow weir. Temperature can be controlled between 30 and 100 degrees Centigrade with an accuracy of plus/minus 0.5 degrees Centigrade. Heating is rapid with an average heat-up rate of 2 to 3 degrees Centigrade per minute depending on the details of the installation. Rapid heating and tight control result in superior etching performance and consistent output.

To make operation of the KOH etching flexible and convenient, the Modutek Teflon tanks systems have standard drain interlocks and low level, high limit, and high-temperature alarms. Temperature process controllers and remote operation timers are also available.

Modutek Teflon KOH tanks are designed specifically for applications such as KOH etching and Modutek can supply custom systems specially adapted to customer requirements. Tank sizes and controls can be designed to match customer applications. Modutek can rely on its experience and expertise to supply KOH etching systems that meet the highest quality standards and deliver the best output possible.

 

Why Particle Removal is Essential in Silicon Wafer Cleaning

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].

 

How Pre-Diffusion Cleans Are Used in the Wafer Cleaning Process

The silicon wafers processed in semiconductor manufacturing facilities and research centers are repeatedly cleaned in aggressive chemical cleaning baths used to remove surface contaminants from the wafers. The cleaning is important because surface impurities affect the diffusion of dopants in the diffusion ovens. Depending on the next diffusion step, wafers have to be completely clean and several types of material may have to be removed. The wafer cleaning process can include multiple cleaning methods to prepare the wafers for the subsequent diffusion step.

Organic Material and Photoresist

When the previous manufacturing step included masking, wafers may still have photoresist adhering to their surfaces. Any such materials have to be removed because they will interfere with the doping process. If contamination is heavy, Piranha etch, a mixture of sulfuric acid and hydrogen peroxide is often used. The sulfuric acid dissolves the carbon-based compounds and the peroxide oxidizes the carbon to carbon dioxide, which is given off as a reaction product.

General Cleaning and Metallic Particles

For lighter organic contamination the two-step RCA clean process (originally developed by RCA Corporation) is often used. The first or SC1 step cleans organic contamination from the wafers but not metallic particles. The second or SC2 step removes the metallic particles and creates a protective layer on the silicon surface.

SC1 clean involves immersing the wafers in an aqueous mixture of ammonium hydroxide and hydrogen peroxide. This removes traces of organic matter and non-metallic contaminants but it leaves metallic particles on the wafer surfaces. These particles have to be removed before diffusion takes place because they may otherwise be embedded into the wafer in addition to the desired doping and cause defects in the semiconductor material.

In SC2, a hydrochloric acid and hydrogen peroxide solution in deionized water dissolves the metallic particles and leaves a clean wafer surface. In addition, a passivation layer is created that protects the silicon from further contamination. The wafers are now ready for further processing.

Native Oxide Layer Removal

The SC1 clean results in an oxide layer forming on the silicon wafers, and even if SC1 is not used, silicon oxide forms naturally on the clean, bare wafers. For some semiconductor fabrication steps, the native silicon oxide layer has to be removed. The silicon oxide layer is stable and very few chemicals can attack and remove it. Hydrofluoric acid is often used but it is extremely dangerous to handle and a safe set-up is important. Usually the wafers are dipped briefly into the acid, which acts very quickly. After a rinse with deionized water and drying, the wafers are ready for the diffusion oven.

Other Cleaning Methods

For some semiconductor fabrication processes, Modutek has pioneered wafer cleaning methods that avoid the use of harsh chemicals. Megasonic cleaning uses megasonic sound waves in a cleaning solution to dislodge particles and clean wafers. Vibrations and the cavitation bubbles of the high-frequency waves dislodge submicron particles and remove contaminating films. Modutek’s ozone treatment is a fast and cost-effective alternative to chemical cleaning for some applications. The ozone converts organic residue to carbon dioxide and does not leave metallic particles behind.

With its extensive experience in wet processing applications and its expertise in providing high-quality wafer cleaning process equipment, Modutek can advise customers on solutions for their semiconductor fabrication needs. The company can evaluate specific fabrication processes and suggest equipment from its complete line, ensuring that the proposed stations fulfill requirements safely and effectively. Modutek’s wet benches support the pre-diffusion cleaning processes as well as general cleaning, stripping and etching and they are available in manual, semi-automated and fully automated stations. Contact Modutek at 866-803-1533 for a free quote or consultation to discuss which process equipment will work best to support your application.

How Wet Bench Stations Are Tailored for Specific Manufacturing Process Requirements

The fabrication of semiconductor wafers requires that an elaborate set of chemical etching, stripping and cleaning steps be followed in a precise procedure that can be consistently repeated. The semiconductor manufacturing process requires that the use of hydrofluoric acid and other chemicals which must precisely controlled and monitored. These high-tech processes are critically important to industries that fabricate semiconductors, medical equipment and photovoltaic cells. They require the use of custom-made wet benches designed to assist in the safe and precise control of corrosive chemicals at high temperatures.

Wet bench equipment

Modutek provides a full range of wet bench equipment to address the specialized needs of semiconductor manufacturing facilities and research centers. Wet bench stations can be tailor made according to the specific manufacturing process requirements of a customer.

Citric-nitric passivation wet benches are critical to the passivation of titanium and stainless-steel parts in various industries. Electro-polishing wet bench equipment is deployed in the medical device industry in the manufacture of precision steel, cobalt chrome and titanium components.

Multistage wet process fume hoods with circulation pumps are used in aerospace component manufacture, printed circuit board fabrication, and the semiconductor manufacturing industry. Modutek’s wet bench equipment for the semiconductor industry meets UL2360/FM4910 standards for fire and contamination safety. This enables fabricators to remain compliant with applicable environmental laws.

Titanium anodizing equipment, agitated immersion washers, in-line conveyor washers, spray cabinet washers and other precision equipment are an integral part of the semiconductor industry, as well. Modutek is an industry leader in the design, development and deployment of these and many other kinds of wet bench equipment.

The precision needed in manufacturing equipment

Sulfuric acid-peroxide is a powerful chemical that is critical to the cleaning processes applied to semiconductor wafers. Effective application of this chemical mixture is inherently unstable and requires constant rebalancing. The rebalancing and control is needed to maintain efficiency. The mixture needs to be constantly replenished with hydrogen peroxide at high temperatures, something that can be costly even in simple material costs. Modutek’s high-tech systems not only ensure the correct concentration levels, they also help fabricators contain material costs through the use of an exclusive chemical re-use system to contain material costs. Every part of the process is maintained and monitored by equipment that is software controlled.

The silicon nitride wet etching process is another semiconductor fabrication stage that requires a high level of precision and control. Silicon nitride is used to mask chemical etchings on silicon wafers. Once an etching successfully completes, the masking material requires removal. Typically, a mixture of phosphoric acid and the ionized water is applied. Precise control over the chemical mixture is needed, however, if only to prevent the risk of dangerous heat levels and explosions. Modutek’s wet bench station design addresses this challenge through the use of high-tech safety features and the use of precision software.

Modutek’s in-house design process

From manual to semi-automated and fully automated wet bench stations, Modutek’s products are designed and developed in-house right down to the software. From servo-controlled robots and automated equipment to low-cost manual stations, Modutek’s equipment covers the needs of the industries they serve. With their in house expertise and 35+ years of operation, the company is well equipped to meet and support the requirements of semiconductor manufacturers and research centers. Developing equipment that provides thorough and precise control of the manufacturing process is what sets Modutek apart from other semiconductor equipment manufacturers. Contact Modutek today at 866-803-1533 for a free consultation or quote on wet bench equipment that can be tailor made to support your specific manufacturing requirements.

 

Advancements in Wafer Fabrication Equipment Improve Semiconductor Manufacturing

While the requirements for high precision control in wafer fabrication have increased, improvements in the fabrication equipment have also kept pace. The higher complexity and smaller size of semiconductor structures require extremely precise process control to ensure adequate output quality and a low component rejection rate. Advancements in automation and in reducing manual handling of the wafers have met these stricter requirements and allowed fabrication shops to increase productivity and reduce costs. Semiconductor equipment suppliers need to provide comprehensive automation solutions to meet in increasing requirements of manufacturers and research centers developing leading edge semiconductor devices.

Automation Advancements

Modutek, a leading semiconductor equipment supplier, provides wafer fabrication equipment that offers fully automated control of the entire processes. Process steps are precisely repeatable resulting in consistent output. Chemical dosage is accurate and the process is executed according to clearly defined steps. While operator intervention is still possible where needed, fully automated stations reduce errors and produce less waste.

Integrated software such as Modutek’s SolidWorks Flow Simulation and SolidWorks Simulation Professional lets operators calculate process variables and track chemical usage. Once the process is programmed, advanced robotics execute the process steps without operator intervention. Operators can rely on a consistent process environment and increased throughput with high output quality.

Both the software and the use of robotics within the automated stations themselves have significantly improved process control and efficiency. Many semiconductor equipment suppliers offer varying degrees of customized solutions for different kinds of wafer manufacturing requirements. At Modutek, both the software as well as the design, assembly and testing of their wet bench stations are carried out at the company’s facilities and are adapted to meet particular process requirements. The ability of suppliers to provide wafer fabrication equipment tailored to meet the unique requirements of semiconductor manufacturers has helped them to improve yields for each specific process they use.

Advanced Equipment Reduces Handling

The last etch process step involves etching the silicon wafer to remove the silicon oxide layer and then drying the clean wafer. Any particle contamination introduced at this point can influence further silicon wafer processing and result in defective or poor quality semiconductor components. Moving the silicon wafers from the last etch process step to a drying chamber risks introducing additional particle contamination. A new product by Modutek combines the last etch (HF) and IPA drying chamber to avoid handling the silicon wafers and substantially reduces the particle count.

The Modutek combined HF last etch and IPA drying chamber is a modified IPA dryer that allows injection of HF acid prior to the start of IPA drying. The ratio-controlled acid etches the wafers down to bare silicon and the wafers are then rinsed with DI water. Once the rinse reaches a pre-defined pH level, the IPA drying process starts with the introduction of IPA vapor from the top. The IPA or Marangoni drying technique avoids watermarks on the wafers. Throughout the process step, the wafers

Benefits from Using Advanced Fabrication Equipment

Modutek offers wet bench stations using the latest technology to improve wafer fabrication equipment and facility performance. With its advanced fully automated stations the company can improve yields by ensuring accurate processing. The software developed in house controls chemical use and precise processing of wafers. The combination of advanced robotics, dedicated software and in house expertise results in consistent, high quality output and reduced costs.

While automation drives a continuous advancement in process reliability and product quality, the elimination of the handling of wafers during transfer into the final drying chamber provides a single substantial improvement through wafer particle reduction. In recent tests only 20 particles (adders) in the 0.3 to 5 micron range were added to the etched substrate in the combined etching/drying system. This single step improvement in the fabrication process can often justify the cost of acquiring the advanced fabrication equipment that will subsequently increase facility performance and profitability.

Modutek has over 35 years of experience providing fully automated wafer fabrication 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 meet a customer’s application requirements.

Modutek Named Among Top Suppliers in Global Semiconductor Wafer Cleaning System Market

Modutek is a supplier of wet bench technology, wet processing and chemical handling stations to the semiconductor fabrication industry. The company was recently named as one of the top suppliers in the global semiconductor wafer cleaning system market research report published on eMarkets Europe. Modutek emphasizes in house development of its software and equipment and focuses on a high level of customer support, leveraging the expertise of its own engineers to offer both standard and customized systems. At the forefront of innovative development, the company offers complete solutions to improve semiconductor fabrication facility performance and output quality.

The Characteristics of a Top Supplier

To become a top supplier in any industry a company has to supply high quality equipment that meets the needs of customers over an extended period of time. In the case of semiconductor equipment manufacturers, it means offering silicon wafer processing stations that execute the customer’s processes precisely with high output quality at a reasonable total cost of ownership. Top suppliers will know the details of the different etching, stripping and cleaning processes and will have developed equipment and software that handles them safely and effectively.

Modutek has been supplying the semiconductor equipment industry for over 35 years, building a reputation for high levels of competence and innovation. The company’s wet bench stations support all the common chemical processes for wafer fabrication and Modutek has developed innovative software and process steps that help reduce customer costs while increasing throughput and minimizing defective or low-quality semiconductor products. Modutek’s in house expertise resulting from designing, building and testing its own equipment allows the company to offer customized systems that exactly meet the needs of each customer. A high level of customer service completes the focus on customer satisfaction.

Innovation and Customer Focus

Modutek has become a top supplier to the global semiconductor wafer cleaning system market by introducing innovative solutions to address customer concerns in a changing technical and commercial environment. In general, the company introduces new systems that increase productivity while reducing costs. More specifically, new products allow for maintaining or even increasing yield in the face of challenges from denser component packing and more complex microstructures on the silicon wafer.

In an initiative to reduce wafer particle counts by eliminating particles added during the move from the last etch to the drying chamber, Modutek has introduced a single chamber process. Instead of exposing wafers to contamination during additional handling, the HF acid last etch and IPA drying are performed in the same chamber, eliminating a transfer step. In recent tests, Modutek has been able to demonstrate that the single chamber process is effective in achieving very low particle counts and higher quality outputs.

In addition to such specific innovations, Modutek has developed comprehensive automation solutions that help reduce error and waste. The fully automated Modutek wet process stations deliver accurate chemical dosages and precise process times to ensure exact execution of programmed process steps. Such automation is cost-effective and provides the tight process control required for the latest wafer fabrication tasks.

The Benefits of Choosing Modutek as a Supplier

In addition to the company’s lengthy experience as a semiconductor equipment manufacturer in a field that has a high turnover of suppliers, Modutek distinguishes itself through its in house expertise. All software and equipment design is carried out by Modutek engineers and all equipment is assembled and tested in house. As a result, Modutek can offer unparalleled service and support without having to call on third parties to help out. As a top supplier to its market, Modutek can propose the right solutions to particular customer’s requirements deliver the needed equipment from its extensive range and offer seamless support as needed.

Changes to the SPM Process Improves Efficiency and Results

The sulfuric acid hydrogen peroxide mixture (SPM) process effectively strips and cleans wafers but suffers from instability due to the decomposition of the hydrogen peroxide. A heated bath improves performance but increases the rate at which hydrogen peroxide changes into water. Periodically spiking the mixture with extra hydrogen peroxide can restore the required concentration but affects the strip rate. As a result, the SPM mixture has to be changed frequently, leading to high costs for chemicals and frequent downtime on wet bench stations. Working closely with a local semiconductor manufacturer, Modutek has developed a “bleed and feed” process upgrade that addresses these problems and results in substantially longer mixture life and improved process results.

The SPM Process

A typical mixture for the SPM strip and clean process is one part hydrogen peroxide to three parts sulfuric acid. The sulfuric acid parts can go as high as 7 parts but once the process has started, if the concentration changes, the strip rate can change as well. The mixture is heated to 130 to 140 degrees centigrade to increase the strip rate. The higher the temperature, the faster the hydrogen peroxide decomposes to water, diluting the mixture.

To keep hydrogen peroxide in the mixture, more of the chemical is periodically added to the process, spiking the concentration back to its original level. Despite this, the mixture is normally usable for only a few hours at a time and typically has to be replaced several times a day. Replacing the mixture is costly and requires repeated downtime when processing has to wait for a new pour. In addition to the costs of the chemicals, there are treatment and disposal costs that are required to comply with environmental regulations.

Modutek’s “Bleed and Feed” Process Change

Modutek has developed a hydrogen peroxide spiking method that keeps the chemical mixture at a predictable concentration and avoids the requirement for frequent replacement. The method reduces consumption of the chemicals and lets the system run for extended periods without down- time.

Using a two-tank dirty and clean tank process, the “bleed and feed” method involves draining a programmable amount of mixture from the dirty tank prior to each process step. Another programmable amount is fed from the clean tank to the dirty tank. Then programmable amount of sulfuric acid is added to the clean tank and both tanks receive programmable amount of hydrogen peroxide.

When the entire mixture has to be replaced, normally about once every week, the system has a quick drain feature that reduces down time and gets the process up and running again quickly. The whole “bleed and feed” spiking method is PLC controlled and the periodic adding and spiking of chemicals allows the mixture to be used continuously for days at a time.

Benefits of the Modutek Process Change

In addition to savings related to the reduced use of chemicals, the new update improves overall efficiency and achieves better results. Instead of having to shut down the wet bench station every shift to pour new acid, the process can run for days and only requires a complete chemical change once per week. In addition, the process is cleaner and can deliver better cleaning and stripping performance.

Modutek is offering the SPM process upgrade on their new wet bench stations and can provide details regarding chemical use and performance. The company has the experience and expertise to help customers more effectively use the SPM and other processes to ensure they obtain the results they need. Call Modutek at 866-803-1533 for any questions you have with using either the updated SPM process or other wet processes needed for your application.