Category Archives: Wet Processing Equipment

Advanced Wafer Drying using Modutek’s IPA Vapor Dryer

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Advanced Wafer Drying using Modutek's IPA Vapor DryerThe successful manufacture of tightly packed semiconductor products depends on obtaining low particle counts on silicon wafer surfaces after rinsing. Heat drying and spin dryers may leave water marks and residue as the water evaporates. Modutek’s advanced IPA vapor dryers use the Marangoni drying effect to reduce particle counts to a minimum. The compact dryer unit can be integrated into wet processing equipment as needed. Modutek’s IPA vapor dryers can increase yields and improve output quality based on reduced particle counts compared to other drying methods.

How the IPA Vapor Dryer Works

In Modutek’s IPA Vapor dryer, an even vapor distribution is ensured by introducing the IPA vapor at the top of the dryer. The vapor is generated in a standard one-gallon bottle located in the exhaust compartment and fitted with a level sensor. Changing the bottle is quick and easy. This arrangement reduces IPA consumption but allows enough vapor to develop the surface tension gradient. As water drains from the bath and runs off the silicon wafer, a small amount of IPA vapor interacts with the thin film of water still coating the wafer. Because IPA has a lower surface tension than water, the surface tension gradient causes the water to flow off the wafer surface. As the water retreats, its flow takes along contaminating particles and other impurities, leaving the wafer completely clean. Because no water is left on the wafer surface, water marks from evaporating water are eliminated.

Advanced Wafer Drying Delivers Many Advantages

The main advantage of using Modutek’s IPA vapor dryer is the reduced particle count. Spin dryers can add particles from the centrifugal action of the spinning. Also, some water will be left to dry, leaving water marks. The Marangoni drying effect utilized in the IPA Vapor Dryer significantly improves wafer cleanliness. Other advantages of Modutek’s dryer include compact installation, low IPA use, and a simple design with no moving parts. The dryer design is flexible enough so that it can be integrated into wet processing equipment. The dryer function can use the same tank as rinsing to save space with a single cabinet. Since the wafers don’t spin, there is no risk of breakage, and a typical drying cycle is completed in ten to fifteen minutes.

The Use of Modutek’s IPA Dryer Can Provide Substantial Benefits

A semiconductor manufacturer can reap substantial benefits when Modutek’s IPA vapor dryer is integrated into wet processing equipment. These include the following:

  • Higher throughput due to faster drying times
  • Higher yields due to fewer defects from contaminating particles
  • Lower costs because of low IPA consumption
  • Reduced space due to compact cabinet construction and integration with rinsing
  • No IPA heating required
  • Flexibility due to multiple drying recipes
  • Easy operation with PLC and touchscreen
  • Safe operation with safety interlocks, auto lid, and PVC side shields
  • Interface capable of working with robotics in wet bench
  • No breakage from spinning because there are no moving parts

Additional Features for Specific Applications

In addition to the direct benefits listed above, Modutek’s dryer can be adapted to specific wet process applications. Possible options include an ozone feature that introduces ozone into the cabinet, a quick dump feature, a static eliminator, data logging, and fire suppression. The dryer can handle all wafer sizes and most glass substrates.

Modutek Provides Solutions to Meet Customer Needs  

Modutek understands wet-process semiconductor manufacturing and has the in-house expertise to find the best solutions. When working with customers, Modutek can evaluate customer needs and make specific proposals from their complete line of wet-processing equipment. After delivery and installation, Modutek provides unparalleled support to ensure the equipment continues to meet customer expectations.

Why Megasonic Cleaning is Essential for Silicon Wafer Processing

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Why Megasonic Cleaning is Essential for Silicon Wafer ProcessingAdding Megasonic cleaning to standard wafer cleaning methods can reduce costs and improve overall semiconductor fabrication performance. Megasonic cleaning is especially useful for manufacturing silicon wafers with the smallest geometries, where almost complete particle removal is necessary for successful manufacturing. The process uses high-frequency sound waves to clean wafer surfaces and can be integrated into wet bench processing stations. Megasonic cleaning is becoming more essential for silicon wafer processing as product complexity increases.

Megasonic Cleaning Can Lower Costs

When Megasonic cleaning is incorporated into a silicon wafer processing line, lower costs can result from reduced chemical use and increased yields. The cleaning method uses only plain water in the cleaning bath and can be substituted for some chemical-based cleaning steps. For some cleaning applications, inexpensive solvents or mild detergents can be added to the cleaning solution. For example, Megasonic cleaning is often used after RCA clean to produce optimum cleaning results and reduce additional chemical usage.

When used with conventional cleaning methods, Megasonic cleaning results in cleaner wafers to reduce particle counts. Defects on the final semiconductor products are reduced. Yields increase because the reject rate is lower, and output quality increases.

How Megasonic Cleaning Reduces Particle Counts

Megasonic cleaning uses high-frequency sound waves to gently dislodge the smallest contaminating particles when wafers are emersed in a cleaning bath. During the last few years, several semiconductor manufacturers have been producing semiconductor devices that use 7 nm technology. Two leading-edge semiconductor manufacturers have recently done die shrinks to support the production of devices using 5nm and 3 nm processes. With increasingly close packing of semiconductor components, thinner conducting paths, and smaller structures, tiny contaminating particles on the wafer surfaces can block etching and cause component defects. The smaller geometries are especially sensitive to particles down to sub-micron size.

In the Megasonic cleaning process, a high-frequency generator produces an electric signal in the megahertz range. A transducer immersed in the cleaning solution converts the electric signal to sound waves. As the sound waves travel through the cleaning bath, they generate microscopic cavitation bubbles. The bubbles are formed in the sound wave troughs at low pressure and burst at sound wave high-pressure peaks. When a bubble bursts, it releases an energetic cleaning solution jet that strikes the wafer surface and cleans off contaminants. While the jet is powerful enough to remove foreign material from the wafer, it will not damage the underlying silicon.

Chemical cleaning methods effectively remove contaminants, but particles often remain on the wafer surface due to electrostatic and surface tension effects. The chemical action and rinsing are insufficient to remove many of the smallest particles. Megasonic cleaning and the action of the microscopic bubbles and jets dislodge these particles so that they can be rinsed away. The clean wafer is almost completely free of contaminating particles and ready for subsequent processing steps.

How Modutek Integrates Megasonic Cleaning into Semiconductor Manufacturing

While Megasonic cleaning improves cleaning performance throughout the semiconductor manufacturing process, low particle counts are especially critical for pre-diffusion cleans. Modutek has developed a complete line of wet bench stations designed and built using their in-house expertise. As a result, Modutek’s experts can advise customers on how to best integrate Megasonic cleaning in their process line and where it would be the most effective.

Modutek can also evaluate if a final Megasonic pre-diffusion cleaning step would improve process results and recommend additional Megasonic cleaning before critical etching steps. Fabrication with the smallest geometries will benefit the most from using Megasonic cleaning. When customers find that their particle counts at critical process steps are too high, Modutek can help find solutions using Megasonic technology.

Modutek Works with Customers to Provide Solutions

 As a leader in wet process semiconductor manufacturing equipment, Modutek works closely with customers to identify problems and provide innovative solutions. When customers need to upgrade their existing wafer cleaning process, Modutek can incorporate leading-edge technologies to improve wafer cleaning performance.

 

How Optimum Particle Reduction is Achieved in a Wet Bench Process

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When microscopic particles remain on the surface of silicon wafers during a wet bench process, the resulting semiconductor products may be of reduced quality or even defective. As semiconductor geometries and microscopic structures become smaller and are packed more densely on a silicon wafer, the presence of particles can influence the etch rate around the particle and compromise semiconductor fabrication. The smallest structures and conductor paths can be influenced by particles in the submicron size range and these particles are especially difficult to remove completely.

Modutek has developed innovative solutions that achieve particle reduction through reduced handling of wafers and excellent particle removal. The single chamber IPA Vapor Dryer and the use of megasonic cleaning deliver excellent results. The reduced particle count produces better yields and higher quality output. At the same time, Modutek’s solutions save money through the reduced use of chemicals.

The Single Chamber IPA Vapor Dryer Keeps the Particle Count Low

Modutek’s single chamber IPA Vapor Dryer incorporates rinsing and drying in a single system to save space, reduce costs, and minimize the handling of silicon wafers. The system initially rinses the wafers with de-ionized water and then introduces IPA vapor into the drying cabinet. The vapor comes from a one-gallon bottle that is located in the exhaust compartment for easy changing.

IPA vapor is introduced into the drying chamber from the top to ensure even distribution and reduce the amount of IPA required. When the IPA vapor condenses on the wafers, a surface tension gradient develops between the IPA and the remaining water. When water flows off the wafer surfaces it can remove the contaminating particles. The dry wafer surface doesn’t have any water marks and no particles are added.

One source of particles is the handling of wafers during transfers between stations. Reducing the number of transfers eliminates a source of particle contamination. Modutek’s Single Chamber IPA Vapor Dryer can handle an optional etching feature and drying in the same system. The wafers are rinsed and dried without transferring them to a new station. Since no additional particles are introduced during this process the particle count is kept to a minimum.

Megasonic Cleaning Effectively Removes Particles Without Toxic Chemicals

Megasonic cleaning relies on high-frequency sound waves in the cleaning solution to remove contaminating particles from wafer surfaces. Modutek has partnered with Kaijo Corporation, a world leader in megasonic cleaning systems to incorporate this technology in their wet bench equipment.

A megasonic generator feeds a high-frequency signal to a transducer immersed in the cleaning tank liquid. The transducer converts the signal into sound waves that travel throughout the tank. The sound waves generate microscopic cavitation bubbles that produce a scrubbing action to clean wafers. Particles on the surface of the wafer are dislodged and washed away.

The higher the megasonic frequency, the smaller the cavitation bubbles and the gentler the cleaning action. The microscopic structures etched into silicon wafers are very delicate and could be damaged with rough cleaning. Megasonic cleaning uses frequencies of 950 kHz and higher. The tiny bubbles of megasonic cleaning deliver gentle cleaning action without damaging fragile silicon structures.

Although megasonic cleaning works well with DI water or an SC1 process, adding a mild detergent or solvent can improve cleaning performance. Particles on silicon wafer surfaces often adhere to the surface and can be difficult to remove. Submicron particles may stay within a surface boundary layer, resisting removal. The microscopic bubbles can dislodge such particles, but the addition of solvents or detergents helps dissolve the bonds holding the particles to the surface and can improve particle removal.

Modutek Innovates to Help Meet Customer Challenges

Modutek works closely with customers to identify issues with wet process applications and continually works on developing new innovative solutions. The Single Chamber IPA Vapor Dryer and the megasonic cleaning process are innovations that help reduce particle counts while reducing chemical use and lowering costs. Modutek’s experience with wet processing equipment ensures customers will continually be able to improve their process performance results. Contact Modutek to schedule a free consultation to discuss your specific process requirements.

Free Standing IPA Vapor Dryer Improves Wafer Processing

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When a series of semiconductor manufacturing steps are complete, the silicon wafers have to be rinsed and dried. At this stage in the fabrication process, the surface of the silicon wafer has to be as free as possible from particle contamination wafer and free from water marks caused by the water evaporating on the wafer. The free-standing IPA vapor dryer uses IPA (isopropyl alcohol) to eliminate water marks and reduce the particle count. IPA vapor drying, also known as Marangoni drying, delivers clean wafers for improved processing by increasing yield and output quality.

IPA Vapor Drying Works by Removing Water from the Wafer Surface

In IPA vapor drying, the silicon wafers are first rinsed with deionized water. IPA vapor is then introduced into the closed drying chamber. Where the IPA interfaces with the deionized water on the wafer surface, the lower surface tension of the IPA causes the water to flow off the wafer surface, taking impurities with it and leaving the wafer clean and dry.

This method of drying silicon wafers is a good alternative to spin drying because it does not stress the wafers mechanically and leaves no water marks. Rinsing and drying takes place in a single unit, avoiding a transfer of the wafers and eliminating a source of contamination. The IPA drying method can be cost-effective, especially if the consumption of IPA is kept low. IPA drying gives excellent results in terms of low particle counts and wafer cleanliness.

Modutek’s IPA Vapor Dryer Provides Superior Performance with Low Operating Costs

Modutek’s free-standing IPA vapor dryer is made from polypropylene with Teflon fittings and pipes. Its 30-inch wide space-saving design can easily be integrated into a wet processing equipment production line or used independently to rinse and dry wafers. The IPA vapor is introduced at the top of the enclosure from a standard one-gallon bottle located at deck level in the exhaust compartment for easy bottle changes. From the top, the vapor is distributed evenly throughout the chamber. Drying time is typically about ten to fifteen minutes.

In addition to the basic drying function, Modutek’s design also includes de-ionized water degassing, N2 head case purging, and hot N2 drying. The station is operated from a touch screen with an intuitive graphic user interface that allows the programming of multiple operating sequences.

Features include a continuous flow deionized water manifold, an automatic lid that opens with a foot switch, and removable PVC side shields. Options include a manual lid, a quick dump feature, data logging, and the use of ozone to eliminate remaining organic impurities. For special applications, Modutek can adapt the dryer design to meet customer requirements.

Advantages and Benefits of the Free Standing IPA Vapor Dryer

With vapor generation inside the standard bottle and vapor introduction from the top of the enclosure, Modutek’s IPA vapor dryer has a very low IPA consumption and low operating costs. The included features and options along with possible customization allow for flexible operation and make the dryer an ideal addition to a semiconductor fabrication line. Excellent rinsing and drying performance, rapid operation, and programmable cycles deliver superior results and higher throughput. Clean wafers with low particle counts can reduce rejects and improve yield. The flexible design makes the station suitable for production lines, batch processing, and individual prototyping or test products.

Based on the company’s extensive experience in the design and building of semiconductor manufacturing equipment, Modutek can advise customers on the type of system they need and can deliver equipment from its complete line of wet process stations. Modutek designs and builds all its own products in-house and has the expertise to ensure IPA vapor dryers and other equipment meets the needs of customers and performs as required. Contact Modutek for a free quote or consultation to discuss your specific requirements.

How Megasonic Cleaning Improves Silicon Wafer Manufacturing

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When silicon wafers are cleaned between manufacturing steps, it is critical to remove all contamination from the wafer surfaces. The remaining traces of process chemicals or microscopic particles can disrupt the etching process and result in defective or low-quality semiconductor devices.

Megasonic cleaning uses high-frequency sound waves in the cleaning tank to remove contaminants and particles from the silicon wafers. The technology can save time and money because it works quickly and does not require expensive chemicals. Silicon wafers cleaned with Megasonic cleaning are completely clean with a reduced particle count. As a result, the technology can improve the operation of semiconductor manufacturing lines for semiconductor fabricators and research labs.

Megasonic Cleaning Reduces the Use of Toxic Chemicals

The cleaning of silicon wafers after the completion of each semiconductor manufacturing step is accomplished by soaking the wafers in mixtures of chemicals including hydrochloric acid or sulfuric acid. In addition to the cost of the chemicals themselves, there are ongoing costs related to the storage, delivery, and disposal of these chemicals. The possibility of leaks and the disposal of the waste chemicals represent environmental hazards that are continuously being mitigated with tighter regulations. Reducing the use of aggressive chemicals can save money beyond their direct cost and can improve the environmental footprint of the semiconductor manufacturing facility.

With Megasonic cleaning, a frequency generator produces an electric signal in the MHz range that is transmitted to a transducer. The transducer that is immersed in the cleaning solution converts the signal to sound waves in the cleaning tank. The sound waves create microscopic cavitation bubbles that deliver a gentle scrubbing action against the surface of the silicon wafer. The cleaning intensity is strong enough to dislodge impurities and contaminants but will not damage the wafer surface or the microscopic structures that have been etched into it.

When Megasonic cleaning is used to replace some of the traditional cleaning steps, the use of chemicals is reduced. Megasonic cleaning uses plain water or water with the addition of mild detergents. The cost benefits and reduced environmental impact can be substantial, and the areas where Megasonic cleaning is used will have increased worker safety and reduced chemical exposure.

Megasonic Cleaning Can Deliver Improved Cleaning Performance

While acid baths work well for cleaning general contaminants from silicon wafer surfaces, ensuring low particle counts can be challenging. Contaminating particles can block etching and cause defects in the final semiconductor devices. As functions become more and more closely packed on the wafer and microscopic structures become smaller, a single particle can affect the etched shapes and current paths. A key factor for improving output quality and reducing defects is reducing particle counts to a minimum.

Microscopic particles can be difficult to remove from the surface of silicon wafers because they often develop a static charge that allows them to cling to the wafer. Chemicals can dissolve the substances that make the particle adhere to the wafer surface but the static charge often remains as an additional bond. With Megasonic cleaning, very small cavitation bubbles form and collapse in tune with the sound wave frequency in the MHz range. When a bubble collapses near the wafer surface, it emits a powerful jet that dislodges any particle still clinging to the surface. Wafers that have been cleaned with Megasonic cleaning systems have a lower particle count as well as a high degree of cleanliness.

Modutek Can Help with Megasonic Cleaning Integration

As a leading manufacturer of wet process semiconductor manufacturing equipment, Modutek can help customers integrate Megasonic cleaning into their wafer cleaning process. Modutek offers free consultation and can show customers how to realize the benefits of lower costs, better output quality, and improved yields.

How the IPA Vapor Dryer Further Improves Wafer Processing

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The Advantages of Using Modutek's Quartz Tube Cleaning StationsWhen silicon wafers are dried after rinsing, the wafer surface has to be free of water marks and contaminating particles. This is especially true after hydrofluoric acid removes the silicon oxide layer during the last etching before further processing. The wafers are subsequently exposed to diffusion or vapor deposition and surface contamination will result in defective components.

During the IPA vapor dryer process, water flows off the surfaces of the wafers without evaporating and leaving water marks. Particle contamination is minimized and the wafers remain clean. The Modutek IPA vapor dryer is a space-saving way of ensuring high-quality semiconductor output for wet process manufacturing facilities and research labs.

Modutek’s IPA Vapor Dryer Delivers Clean Wafers While Reducing Costs

Modutek’s IPA vapor dryer incorporates rinsing and drying in a single station to reduce costs, save space, and minimize the handling of the silicon wafers. The station first rinses the wafers with de-ionized water and then introduces IPA vapor into the drying cabinet. The vapor is generated in a one-gallon bottle situated in the exhaust compartment for easy changing.

The IPA vapor is introduced into the drying chamber from the top to ensure even distribution, reducing the amount of IPA required and further reducing costs. When the IPA vapor condenses on the wafers, a surface tension gradient develops between the IPA and the remaining water. The water flows off the wafer surfaces, taking contaminating particles with it. The dry wafer surface doesn’t have any water marks and is practically particle-free.

Advantages and Benefits of Modutek’s IPA Dryer

Modutek’s IPA dryer lets operators transfer the silicon wafers from the last etch processing station to the dryer chamber without any further movement of the wafers. Wafers are fragile and can easily pick up particles when moved. With the single rinsing and drying chamber, wafers avoid damage and remain as particle-free as possible.

The IPA drying method is a gentler alternative to heat drying or rotating the wafers to spin off excess water. Heating leaves particles in place and thin wafers can break when spun rapidly. Instead, the IPA dryer has no moving parts, eliminating sources of potential damage to the wafers. A drying cycle typically takes around 15 minutes.

IPA dryer cabinets are a compact 30 inches wide and made of white polypropylene. The graphic user interface operates via a touch screen and features multiple recipes. The SolidWorks Simulation Professional and SolidWorks Flow Simulation software calculates process flow characteristics and often reduces the required drying time. The Modutek IPA vapor dryer is a customizable unit that can be designed to fit into customer wet process lines and meet customer requirements.

Modutek Designs and Builds Their IPA Dryer Systems in House

Modutek’s IPA dryer is designed, built and tested at the company’s San Jose, California facility. Modutek does not outsource any of this work and even develops its own software, the SolidWorks Simulation Professional and SolidWorks Flow Simulation programs. As a result, Modutek can offer highly customized versions of its IPA dryer. Modutek engineers can work with customers to integrate the IPA vapor dryer in an existing wet process line or design a custom free-standing unit to meet the requirements of the customer application.

With more than 40 years of experience in wet process semiconductor manufacturing equipment, Modutek can analyze the needs of its customers with a free consultation. The company can then recommend equipment from its complete wet process equipment line and from associated equipment such as tanks, chemical handling equipment and lift stations. In each case, Modutek can offer customized systems and equipment to meet the needs of its customers.

The Advantages of Using Modutek’s Quartz Tube Cleaning Stations

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The Advantages of Using Modutek's Quartz Tube Cleaning StationsAfter a quartz tube is used in a high-temperature semiconductor manufacturing process, it has to be cleaned thoroughly to remove contamination. Process steps such as diffusion leave traces of diffused material on the tube and the high-temperature furnace leaves contaminants. A Quartz tube cleaning station removes the surface contaminants and leaves the quartz tube clean and free of particles, ready for its next use.

Effective Quartz Tube Cleaning Is Critical for Output Quality

Quartz tubes are used as an inert container for semiconductor manufacturing processes such as vapor deposition and diffusion. The wafers inside the quartz tube are inserted into a furnace that can reach 1000 degrees centigrade. The semiconductor characteristics and the circuit paths of semiconductor components are created during these process steps. After use, the quartz tube surface has deposits from the furnace and from the process. Before it can be used again, the deposits have to be removed and the quartz tube has to be cleaned in a way that minimizes the particle count on its surfaces.

In a quartz tube cleaner, an acid spray dissolves the surface contaminants and washes them away. The clean tube is then rinsed with de-ionized water and dried carefully without introducing any new contaminating particles. Because quartz tubes are fragile and because handling them introduces new contamination, a degree of automation for quartz tube cleaning can be beneficial.

Minimizing the particle count is especially important for subsequent semiconductor manufacturing steps such as masking or etching. When micro-structures are etched into the wafers or current paths are created on masked wafers, even a single particle can affect a microstructure or block a current path. Such effects can lead to defective or poor quality semiconductor components. Manufacturing facility throughput is reduced by large numbers of rejected products and output quality can suffer.

Modutek’s Quartz Tube Cleaners Deliver Substantial Benefits

Quartz tube furnaces are typically placed in several locations along a semiconductor production line and each requires reliable cleaning. The benefits of Modutek’s quartz tube cleaning stations include the following:

  • Customization. Modutek designs and builds its quartz tube cleaning stations in house. As a result, the company can easily customize each station to exactly meet specific requirements.
  • Rugged, reliable construction. Made from white polypropylene, the cleaners feature a rugged tube roller system and powerful cleaning nozzles that ensure complete coverage.
  • Safe operation. Operators are protected with PVC safety shields and safety interlocks. The systems include emergency off mushroom buttons.
  • Variety of Options. Modutek offers many options, including hot N2 drying, acid holding tanks and acid mixing, lift stations and onboard bottle washers.
  • Automation. The cleaners can be operated manually or fully automatic. If required, different steps can be automated while others can be carried out manually. Manual operation can test out the cleaning process and then run it fully automated.

Modutek horizontal quartz tube cleaners deliver reliable cleaning with the degree of automation ideal for the specific process application. Handling of the tubes is minimized and an extremely high degree of cleanliness is achieved consistently.

Modutek Designs, Builds and Supports the Equipment Needed for an Application

With its in house expertise and extensive experience in semiconductor manufacturing equipment, Modutek can analyze a manufacturing process and provide equipment to fulfill the process requirements. The complete line of Modutek wet processing equipment is developed in house so that the design and manufacturing knowledge stays in the company. As a result, Modutek can design and build equipment to meet specific needs. Customers can ask for a free consultation and select standard stations from the Modutek wet process line or receive customized equipment that fulfills their requirements.

Achieving Optimum Particle Removal in a Wet Bench Process

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Achieving Optimum Particle Removal in a Wet Bench ProcessAs component packing is tighter and circuit geometries trend towards smaller structures, the reduction of submicron particle contamination during the wet bench process steps becomes more important for output quality. When circuit paths are reduced in size, a single submicron particle can block the path and render the final semiconductor component defective. Even when the presence of particles doesn’t cause defects, their influence on semiconductor performance can reduce the quality and lifespan of the final products.

Semiconductor manufacturing facilities and research labs using typical wet bench equipment face challenges when trying to reduce submicron particle contamination to acceptable levels. Innovative solutions such as the use of Megasonic Cleaning and the reduction of wafer handling with a single chamber IPA dryer can help bring down the particle count. When such solutions are integrated directly into the wet bench processing line, throughput and yields can increase. The process may require fewer chemicals and overall facility performance can improve.

How Megasonic Cleaning Reduces Particle Contamination

The use of high-frequency sound waves in cleaning systems is common in many industries but the delicate silicon wafer structures and surfaces require extra-high frequencies to make sure wafers are not damaged. Megasonic cleaners use frequencies of 950 kHz and higher, in the megahertz range, to deliver the soft cleaning action required.

The sound waves from lower frequency systems create microscopic but comparatively large cavitation bubbles in the cleaning bath. The bubbles produce intense scrubbing against the surfaces of the parts to be cleaned, dislodging contaminants and delivering a powerful cleaning action. For the soft surfaces, delicate structures and thin metallic deposits of silicon wafers, such intense cleaning can result in the pitting of surfaces and damage to silicon structures.

In Megasonic cleaning systems, the high-frequency sound waves produce smaller bubbles and more gentle scrubbing. The cleaning action is soft enough to preserve silicon surfaces and structures but strong enough to dislodge contaminating particles. The particles often adhere to the wafer surfaces and are difficult to dislodge with normal rinsing. Megasonic Cleaning breaks the adhesion and creates currents that wash the particles away.

The Megasonic Cleaning action is especially important for submicron particles where the adhesion to the wafer surface inside a boundary layer makes rinsing less effective. The soft scrubbing of tiny bubbles against the wafer dislodges submicron particles effectively and reduces particle contamination.

How the Single Chamber IPA Dryer Reduces Particle Contamination

One of the ways silicon wafers pick up contaminating particles is during the transfer from etching to drying stations. This transfer is especially critical for HF last etching. During the final etching in a wafer fabrication step, the silicon oxide layer is removed through etching with hydrofluoric acid. The wafer is then rinsed and dried before moving on to the next fabrication step. Particles remaining on the wafer surface can interfere with the subsequent fabrication process.

In an innovative development that eliminates this source of particle contamination, a single chamber handles HF last etching and IPA vapor drying. First, hydrofluoric acid is injected into the station chamber to etch the wafer. When etching is complete, the wafer is rinsed with de-ionized water until the acid is neutralized to a safe pH. IPA vapor is then introduced into the station chamber, and after about 15 minutes, the wafers are dry and ready for the next fabrication step. The particle count remains low because the wafers have not been moved throughout the etching and drying process.

Modutek Provides Innovative Semiconductor Manufacturing Equipment for Excellent Results

Modutek works closely with customers to develop innovative wet bench stations that meet their requirements. Attention to customer needs and finding new solutions to common problems allow the company to remain one of the leading wet bench manufacturers.

For Megasonic Cleaning applications, Modutek has partnered with Kaijo Corporation, a world leader in high sound frequency cleaning technology. Modutek’s integration of the Kaijo Megasonic cleaners into the wet bench product line has produced low particle counts that are difficult to obtain with other methods.

Because Modutek designs and builds its own etching and IPA drying stations in house, the company was able to develop its innovative single chamber station and integrate it into its comprehensive wet process product line. In parallel with Megasonic Cleaning, the single chamber station further reduces particle counts, improves yields and reduces costs. On these and other wet process questions, Modutek offers free consultations to ensure customers get the best equipment for their needs.

How Customized Equipment Improves Silicon Wafer Processing

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How Customized Equipment Improves Silicon Wafer ProcessingBecause semiconductor manufacturing is made up of a large number of steps, silicon wafer processing often includes unique requirements. Standard equipment may be suitable to some extent, but using custom equipment adapted to the particular process can improve production line performance. Customization of the physical characteristics of the system, the software, the degree of automation and the process components can impact how well the silicon wafer processing equipment works. An experienced supplier of wet processing equipment can advise customers regarding possible customization and follow up with specific equipment suggestions.

Physical Customization of Wet Process Equipment

Semiconductor manufacturing equipment often has to fit into a defined space or is retrofitted into an existing production line. In either case, the dimensions have to be customized to fit the available space. Modutek can build processing stations and tanks with special dimensions to fit and can arrange components for less depth or less length as required. Because Modutek designs and builds all its own equipment, the company is capable of changing the dimensions of its standard products to fit customer requirements.

Customized Software for Special Calculations

The Modutek SolidWorks Flow Simulation and Simulation Professional software allows customers to accurately calculate chemical dosages and to track chemical usage. Custom installations may require special calculations and the software may have to be adapted to calculate and track custom chemical use. Modutek writes all its own software and can therefore customize and adapt the program code. Customers can rely on Modutek to maintain and support the non-standard software and make sure it works the way the customer wants.

Automation With Customized Characteristics

Modutek’s standard wet processing equipment is available in fully automated, semi-automated or manual versions but customers may require some automated functions while other functions remain manual or semi-automatic. Prototypes often rely on manual controls to define basic process parameters. Then the process is optimized in semi-automatic operation while eventually running in fully automatic mode when in full production. Existing product manufacturing may require only full automation but the manufacturing process may need operators to execute some manual functions.

Depending on the customer’s manufacturing needs, Modutek can design automation combining manual and automatic controls as specified by the customer. The automatic process may run until operator intervention is required to execute a command or check a specific condition. Modutek can adapt its systems to meet such special automation needs.

Customized Process Components and Subsystems

Process components and subsystems may include chemical delivery, baths or tanks, wafer handling and wafer drying. Modutek can integrate some of these functions into a single unit or place separate units into a custom arrangement. For example, a chemical delivery station can have local or remote tanks and can be placed behind the processing stations to save space. An IPA vapor dryer can include de-ionized water rinsing and vapor drying in one unit. With the company’s experience as a leading wet bench manufacturer, Modutek can design custom arrangements that carry out the required wet process functions within the parameters set by the customer.

Modutek’s Customizations Improve Process Performance

Modutek has a complete line of standard wet process stations, all designed and built in house. For new customized projects, the custom system is evaluated for special requirements and possible solutions. Modutek then works closely with the customer to ensure that the chosen customizations reflect the special process requirements and will produce the expected results.

When Modutek builds such custom systems, they choose customization over standard systems because the customization will improve overall performance. Improvements can include higher throughput, better output quality and lower costs. Working transparently with the customer, Modutek can demonstrate how its proposals will produce better results and ensure that the finished system meets expectations.

How Megasonic Cleaning Reduces Costs and Improves Silicon Wafer Yields

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How Megasonic Cleaning Reduces Costs and Improves Silicon Wafer YieldsBetween process steps that etch silicon wafers and deposit circuit paths, semiconductor manufacturing relies on wafer cleaning to remove material from previous process steps and microscopic contaminating particles. As structures and circuits on wafers decrease in size, even the tiniest particles can interfere with etching and the creation of circuits and micro-structures.

Such interference can cause defects in the final semiconductor product, lower product performance or cause a reduced product lifespan. The use of Megasonic Cleaning results in a gentle cleaning action that dislodges particles from wafer surfaces while leaving the wafer, its circuits and structures undamaged. Megasonic Cleaning reduces chemical use and final product rejection rates using a process that is completely safe and environmentally friendly.

Megasonic Cleaning Delivers Quick Results with Safe, Gentle Cleaning Action

Megasonic cleaning systems generate microscopic cavitation bubbles in the cleaning solution. When a bubble bursts, it produces a tiny jet that dislodges contaminants from the surfaces of the parts to be cleaned. Lower ultrasonic frequencies generate comparatively large bubbles and powerful jets while high frequencies clean with smaller bubbles and less energetic jets.

The tiny structures etched into the silicon and the microscopic metal filaments deposited on the wafers are easily damaged. Products such as microprocessors, micro electro mechanical systems (MEMS), and controllers may not work properly if precise cleaning procedures are not followed. Using frequencies above 950 kHz in the megahertz range for cleaning the wafers ensures that the Megasonic Cleaning action takes place with the tiniest bubbles and the least energetic jets. As a result, Megasonic Cleaning is gentle enough to remove contaminating particles while leaving silicon surfaces, micro-structures and metallic deposits intact.

Reduced Use of Chemicals Saves Money

The traditional wafer cleaning process uses strong chemicals to strip contaminants and particles from wafer surfaces. In addition to the cost of purchasing the chemicals, there are costs for storage, handling and disposal. As environmental regulations become more strict, hazardous chemicals have to be stored in special containment facilities. Chemical delivery systems have to include special measures that guard against spills. Once the chemicals are used, they have to be neutralized and disposed of in a way that doesn’t harm the environment. All these measures are expensive and will become more costly as regulations tighten.

Workplace safety is another costly aspect of the use of hazardous chemicals. Operators have to be protected against inadvertent contact with corrosive materials and many of the chemicals emit dangerous vapors that require expensive ventilation equipment. Operators that work with hazardous chemicals need protective clothing that reduces productivity and work accidents can lead to serious injury.

Megasonic Cleaning removes contaminants from wafers and dislodges particles more effectively than chemical methods. The reduced use of chemicals saves money and leads to a safer, more productive workplace environment.

Modutek’s Megasonic Cleaning Improves Sub-Micron Particle Removal

Modutek has partnered with Kaijo Corporation, a world leader in megasonic and ultrasonic cleaning technology, bringing Megasonic Cleaning to wet bench semiconductor manufacturing. Modutek has integrated Megasonic Cleaners into the company’s wet bench equipment to produce unparalleled low particle counts. The bubbles of the Megasonic Cleaning system agitate the cleaning bath to disrupt boundary layers, allowing effective cleaning action around complex microscopic structures and inside holes. The tiny jets produced by the bursting bubbles break the bonds between the wafer surfaces and surface particles and allow the particles to be removed by cleaning solution currents.

The low particle counts achieved by Modutek’s wet bench stations incorporating Megasonic Cleaning reduce defects and improve yields for semiconductor manufacturing lines. Product quality rises while costs go down. Using the latest Modutek Megasonic Cleaning equipment improves overall facility performance for semiconductor manufacturing plants and research labs. Contact Modutek for a free consultation on selecting the right equipment to meet your manufacturing requirements.