Why Megasonic Cleaning is Essential for Silicon Wafer Processing

Posted on January 24, 2023 by Douglas Wagner

Adding 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 Enhanced Automation Equipment Provides Precision Parts Cleaning

Posted on January 10, 2023 by Douglas Wagner

Enhanced automation equipment provides a more effective and efficient way to clean industrial parts while reducing costs and improving workplace safety. The cleaning methods range from baths with aggressive chemicals to Megasonic cleaning using high-frequency sound waves. For all these cleaning processes, automation can improve consistency and predictability. When the handling of sharp or heavy parts or the mixing of chemicals presents hazards for workers, automation can increase workplace safety. Using enhanced automation equipment can deliver these benefits by taking over the operation of the cleaning process and running it more efficiently.

Automation of the Cleaning Process Can Save You Money

Manual cleaning of parts and monitoring the cleaning process is labor-intensive and time-consuming. Workers must mix the chemicals and place the parts in the bath. If the parts are removed from the bath too soon, the remaining contamination has to be removed by hand. Human error can cause chemical spills or incorrect mixtures. Inconsistencies in the cleaning process can mean poor results that require additional part cleaning.

With enhanced automation, the cleaning process can be optimized. Chemical use is fixed and controlled at optimum values, and spills can be eliminated. Cleaning process times are set, and chemical waste is reduced. Operators can start the automated process and then do other more productive work. When they return, they can remove cleaned parts that are ready for further process steps. Automated precision parts cleaning can reduce costs with lower chemical use and lower workforce requirements.

Automated Cleaning Is Safe for Workers

When workers have to handle parts to be cleaned manually, they must follow safety procedures to minimize the possibility of injuries. Special safety equipment may also be required. Manual cleaning of sharp objects can result in injuries, and handling heavy parts is often difficult, especially when placing them in a chemical bath.

Automated precision parts cleaning systems eliminate many of these safety issues. Heavy parts can be placed in a basket, and the robotics take care of immersing the parts in the chemical bath. The automation system mixes the chemicals and times the cleaning process to ensure all parts are clean. The operators no longer have to handle the chemicals, and the need for manual cleaning is reduced.

Modutek’s Automated Process Stations Can Clean Industrial Parts and Equipment

Modutek has enhanced its automated process stations to clean industrial parts and equipment ranging from the smallest components to parts weighing up to 250 pounds. Typical parts weighing about 50 pounds made of metal or glass can fit into a 2-foot by 2-foot basket. Heavier parts can be placed on a cart and rolled up to the cleaning station. A robot loads the parts into the cleaning station bath, which goes through several automated cleaning and rinsing cycles. The stations can support baskets with parts weighing more than 250 pounds if required. The automated cleaning station design is aimed at cleaning industrial parts that are hard to handle manually.

The automated cleaning process can be observed on a touchscreen showing the major cleaning system components and their status. The touchscreen is also used for programming the cleaning cycles, setting the amounts of chemicals used, the process times, and the rinse cycles. Operators can run the cleaning process and then adapt settings to improve performance. The process is optimized to use the least amount of chemicals to achieve excellent cleaning results.

Modutek’s Expertise in Designing Automated Equipment

Modutek has extensive in-house experience and expertise in designing and building automated process systems. This means Modutek can evaluate customer cleaning processes and requirements and deliver the corresponding industrial parts cleaning equipment to meet their requirements. Modutek’s enhanced automation allows the cleaning stations to reduce chemical use, improve cleaning performance and provide a safer working environment. If you need automated industrial parts cleaning equipment, contact Modutek for a free consultation.

Why Pre-Diffusion Cleans Are Essential for Silicon Wafer Processing

Posted on December 20, 2022 by Douglas Wagner

Silicon wafers must be completely clean before they go through the diffusion process. If contaminating particles are present on the wafer surfaces during the diffusion process, they will cause defects in the final semiconductor product. Pre-diffusion cleaning can be carried out with several methods. RCA clean and Piranha etch use chemicals to strip away wafer contamination. Megasonic cleaning uses high-frequency sound waves to dislodge surface contaminants and particles. No matter which cleaning method is chosen, cleaning must be done to reduce contaminating particle counts to a minimum. An experienced manufacturer of wet process stations can integrate the required cleaning methods into wet benches. They can then ensure that the silicon wafers are cleaned thoroughly.

RCA Clean is a Common Silicon Wafer Cleaning Method

RCA clean was originally developed at the RCA corporation and remains a popular all-round silicon wafer cleaning method. It consists of two parts: Standard Clean 1 and 2 (SC1 and SC2). SC1 removes organic material but leaves metallic contamination behind. SC2 cleans the remaining metallic particles and produces a completely clean wafer.

The SC1 cleaning bath contains a solution of ammonium hydroxide and hydrogen peroxide. The cleaning bath is heated to about 75 degrees centigrade, and the wafers are immersed for 10 to 15 minutes. All organic matter and many insoluble contaminants are removed, but some metallic ions stay attached to the wafer surface.

The metallic ions are removed during the SC2 cleaning step. The wafers are placed into a solution of hydrochloric acid and hydrogen peroxide. The solution is heated to about 75 degrees centigrade, and the wafers are immersed for about 10 minutes. Once the wafers are rinsed with deionized water and dried, they are ready for the diffusion processing steps.

Piranha Etch Quickly Cleans Heavy Contamination

When silicon wafers are heavily contaminated or need to be stripped of photoresist from previous process steps, a Piranha mixture is often used to begin the wafer cleaning process. The mix of sulfuric acid and hydrogen peroxide quickly removes large amounts of mainly organic contaminants. While it works more rapidly than RCA clean, it operates at an elevated temperature of 130 to 180 degrees centigrade and is hard to control precisely. Modutek’s proprietary “bleed and feed” process control improves process stability. The advanced controls allow for more precise temperature settings and better cleaning performance while maintaining the rapid removal of contaminants.

Megasonic Cleaning Provides Improved Removal of Contaminating Particles

Megasonic cleaning uses high-frequency sound waves in the cleaning bath to dislodge light contamination from wafer surfaces. The cleaning method features reduced use of toxic and expensive chemicals while reducing particle counts to a minimum. Even the smallest sub-micron particles can distort diffusion and cause defects in the final semiconductor product. These tiny particles are especially difficult to remove because they tightly adhere to wafer surfaces due to static charge and surface tension. Megasonic cleaning generates microscopic bubbles in the cleaning solution. When these bubbles collapse, the resulting scrubbing action removes the particles.

Modutek’s Wet Benches Support Pre-Diffusion Cleans for Specific Wafer Processing Requirements

Modutek wet process stations support all standard silicon wafer cleaning methods. Pre-diffusion cleans can be integrated into a wet bench to satisfy specific customer requirements. Since Modutek designs and builds equipment in-house, wet bench stations can be customized to meet specific customer needs. Based on its in-house expertise, Modutek can recommend solutions for wafer processing and propose equipment from its complete line of wet process stations. Once the equipment is built and delivered, Modutek can provide continuous customer support for the supplied stations. Contact Modutek for a free consultation to discuss your specific process requirements.

How Precise Control of the SPM Process Improves Processing Results

Posted on December 6, 2022 by Douglas Wagner

While the SPM (Sulfuric acid Peroxide Mix) or Piranha process quickly removes organic contaminants such as photoresist, it is difficult to control. The cleaning action depends on both the temperature and the concentration of the mixture. Both vary if the process is left to carry on without intervention. Better controls can improve cleaning performance, reliability, and repeatability while increasing the lifespan of the mixture. Modutek has developed advanced controls that maintain temperature and concentration precisely at their desired levels to improve cleaning results.

The SPM Process Suffers from Decreasing Concentration and Slower Cleaning

The SPM mixture is typically about three parts sulfuric acid to one part hydrogen peroxide. The preparation of the mixture is highly exothermic. Once the mixture stabilizes, the wafer cleaning process occurs in a heated tank at 130 to 180 degrees centigrade. The hydrogen peroxide is unstable and decomposes to form water and oxygen. As the amount of water in the mixture increases and the concentration of hydrogen peroxide goes down, the cleaning effectiveness of the mixture deteriorates.

Small amounts of hydrogen peroxide are periodically added to the mixture to correct the problem of a decreasing hydrogen peroxide concentration. This spiking with hydrogen peroxide causes a sudden temperature increase due to the exothermic nature of the mixing process. While spiking solves the problem of a decreasing hydrogen peroxide concentration, the temperature can’t be kept constant. An SPM mixture that is not spiked is useful for about two hours, but spiking with hydrogen peroxide increases the lifespan of the mixture to about one day.

Modutek Has Developed Advanced Controls to Improve Process Results

Modutek’s “Bleed and Feed” process control strategy keeps the concentration of hydrogen peroxide and the mixture temperature within narrow limits. The temperature variations due to spiking and the need for spiking are eliminated. With concentration and temperature controlled accurately, the strip rate of the mixture remains constant and predictable. Reliable timing and repeatability of the process are excellent.

Modutek achieves these results by using a two-tank control system. The process tank is the “dirty” tank, while the second tank is the “clean” tank. At periodic intervals, a small amount of the mixture is drained from the dirty tank. It is replaced with a fresh mixture from the clean tank. The clean tank mixture is then replenished with new chemicals. A programmable controller controls the process, so the dosage intervals and the amount of mixture to be drained are adjustable and recorded by the programmable controller. As a result, once the process controls are optimized, the SPM wafer cleaning process can be run exactly the same way each time.

Modutek’s “Bleed and Feed” Reduces Costs and Provides Benefits

Customers who have switched to Modutek’s “Bleed and Feed” controls find that their costs are reduced, and the process line performance is better. Modutek’s control strategy reduces chemical use, and the mixture lasts longer when the temperature variations caused by spiking are eliminated. Downtime due to having to replace the bath chemicals is reduced as well. The risk of accidents from operators adding too much hydrogen peroxide or from spills is eliminated. In addition to savings from lower chemical purchases, reduced costs include lower chemical handling, storage, and disposal expenses.

Support for the “Bleed and Feed” Process

Modutek offers the “Bleed and Feed” process controls for the SPM process on new wet process stations. As one of the leading semiconductor equipment manufacturers, Modutek continues to work on improving its silicon wafer cleaning equipment to meet customer needs. Since Modutek designs and builds its equipment in-house, innovative features can be developed to support unique customer requirements. Wet bench processes are often specialized, and Modutek can utilize in-house expertise to customize equipment as needed. Innovation and customization make Modutek a valuable partner for wet bench technology.

Why Acid Fume Scrubbers are Required for a Safe Work Environment

Posted on November 17, 2022 by Douglas Wagner

When wet bench processes use acids to clean, strip, and etch silicon wafers, their exhaust air contains acid mist. This air can’t be released into the workspace because it can harm employees and corrode equipment. Acid fume scrubbers remove acid mist from the exhaust air. They neutralize the acid exhaust and deliver clean air that is safe to release into the outside environment. Modutek’s acid fume scrubbers can remove up to 99 percent of acid mist and are easy to operate. They are available in a wide range of capacities and can be integrated into the wet bench processing line.

Acid Fume Scrubbers Work by Neutralizing Acid Exhaust

Acid fume scrubbers pass the acid mist over a bed containing neutralizing chemicals. The chemicals absorb the acids in the exhaust, and the resulting chemical reaction changes the acid into a harmless solution. The air from the acid fume scrubber is clean, and the neutralized discharge liquid can be recycled. The operation of the acid fume scrubbers is reliable and safe.

To maximize the absorption of acid mist by the neutralizing chemicals, Modutek uses a high-surface packing material. Supplied by industry leader Lantec, the packing material is kept wet with a neutralizing solution. Because of the many protuberances and crevices in the packing material, more acid mist can be absorbed as they pass over the packed scrubber bed.

The high efficiency of Modutek’s scrubbers has to be matched with the proper flow of exhaust air. Modutek offers scrubbers with flow capacities from 500 to 25,000 CFM. This wide range of capacities is suitable for fabrication lines from the smallest research lab facility to large manufacturing plants. In addition to cleaning acids from the exhaust air of wet process stations, Modutek’s acid fume scrubbers can be used with other chemical handling equipment. Any process that produces an acid exhaust can benefit from using Modutek’s acid fume scrubbers.

Almost all acids are removed when the exhaust from the wet process station matches the scrubber’s flow capacity. Modutek can incorporate acid fume scrubbers within their wet bench stations to provide an integrated solution. Acid fume scrubbers provide a simple, low-cost way to neutralize acid exhausts from chemical processes.

Advantages and Benefits of Modutek’s Acid Fume Scrubbers

Modutek’s acid fume scrubbers are designed to provide customers with ease of use and low operating costs. The operator interface is intuitive and gives operators all the information they need with regard to pressures, flow, liquid levels, and discharge. Water use is low, and maintenance is designed to be easy and quick. There is a bottom drain, and the scrubbers have a double containment system to avoid leaks and reduce spills. Custom-built acid fume scrubbers are available to meet most acid exhaust neutralization requirements.

Design and construction deliver the following benefits:

Operators can quickly learn to use the simple interface and meet clean air targets
High air cleaning efficiency improves workplace safety
The wide range of capacities means almost any facility with acid mist exhausts can find a suitable scrubber model
Low operating costs and low total cost of ownership make Modutek’s acid fume scrubber an attractive choice

Modutek Provides Reliable Wet Bench and Chemical Handling Equipment

As a leader in wet bench technology and chemical handling equipment, Modutek helps support customers with their semiconductor manufacturing needs. In addition to acid fume scrubbers, Modutek offers a complete line of wet bench stations and equipment and can advise on new additions and upgrades to existing systems. Whether it’s a stand-alone acid fume scrubber, an integrated wet process station, or a complete production line, Modutek can provide reliable equipment to meet your requirements. Contact us for a free quote or consultation to discuss your specific requirements.

How Quartz Tanks Provide High Reliability and Safety for Wafer Processing

Posted on November 3, 2022 by Douglas Wagner

Because quartz is an inert substance that does not take part in acid chemical reactions, quartz tanks are ideal containers for silicon wafer processing. The flame-polished quartz used in Modutek’s quartz tanks is impervious to the powerful acids used for processes such as SC1, SPM, and the Piranha process. Quartz tanks are designed to minimize particle contamination and to accurately control the temperature when required. As a result, quartz tanks deliver superior results for wet bench semiconductor fabrication.

Quartz Tanks Reliably Reduce Particle Counts

As semiconductor products require tighter packing of components, a reduced particle count becomes more important. The size of the microscopic structures etched into silicon wafers is reduced to such an extent that a single particle can distort the required shape. The resulting semiconductor chips can be defective or have reduced quality. Sometimes the performance could be better, or the lifespan is reduced. A low particle count is critical for achieving excellent quality output and a high yield from the semiconductor fabrication line.

Modutek’s quartz tanks reduce particle contamination to improve process results. The high-purity flame-polished quartz used in Modutek’s quartz tanks makes it chemically inert to most chemical compounds, including acids, water, and salt. Since the quartz crystal does not react with the chemicals used in semiconductor fabrication, contamination from the quartz tanks is eliminated.

The quartz tank design reduces particle contamination as well. Modutek’s quartz tanks are based on over 30 years of tank design experience to minimize particle contamination. The seamless design and sloped housing construction eliminate places where particles could become lodged. Actual results from real-world fabrication confirm that Modutek’s quartz tanks deliver low particle counts.

Accurate Quartz Tank Temperature Controls Produce Precise Results

For many wet bench processes, the etch rate depends on how the process is set up. The temperature, concentration, silicon wafer crystal lattice orientation, and possible doping of the silicon wafers all influence the etch rate. Except for the process temperature, they are all determined at the start of the process. The temperature, on the other hand, varies. It rises quickly at the beginning and can change as the etching progresses. Precise temperature control is required for reliable etching results.

The etch rate is critical for determining the shapes and details of the microscopic structures etched into the silicon wafer. If etching does not proceed at the right speed, the etched shapes may be too large or too small. The resulting semiconductor products won’t have the expected characteristics and may have to be discarded.

Modutek’s quartz tanks feature a rapid temperature rise to the temperature set point and precise control. The temperature can be set at up to 180 degrees Centigrade. The temperature rises at up to 2 degrees C per minute and is controlled with a precision of plus/minus 1 degree C. The rapid temperature rise helps achieve high throughput, and the tight temperature control provides excellent repeatability.

Quartz Tank Design Influences Output Quality

The quality of silicon wet etching results depends on low particle counts and accurate control of the process temperature. Modutek’s quartz tanks are designed with these two factors in mind. The tanks support wet bench processes such as SC1 and SPM and deliver consistent etching results. Reduced particle counts and excellent etch rate control are consistent during continuous manufacturing and across different batches.

Modutek Provides Safe and Reliable Equipment

Modutek works closely with customers to improve their wet processing manufacturing results, resolve problems and find solutions. Quartz tanks and other equipment that Modutek provides deliver high reliability and safe operation to support various wet processes. Contact us for a free quote and consultation to discuss your specific requirements.

How to Order a Wet Bench for Your Specific Process Requirements

Posted on October 18, 2022 by Douglas Wagner

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

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

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

Make Sure Your Choices Don’t Impose Unwanted Physical Constraints

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

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

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

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

The Wet Bench Equipment Needs to Support the Wafer Manufacturing Process

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

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

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

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

How Automated Controls Improve Silicon Wafer Manufacturing

Posted on October 6, 2022 by Douglas Wagner

How Automated Controls Improve Silicon Wafer Manufacturing Precise automated controls that are incorporated into wafer manufacturing equipment help manufacturers meet the challenges of higher component densities and compliance with environmental regulations. They provide excellent repeatability and accurate chemical dosages that precisely control the etch rate and the cleaning and stripping processes. Chemical neutralization and disposal are handled automatically with document generation to prove regulatory compliance.

In addition to delivering improved process control, the automation software can easily be customized for specialized process requirements or updated to reflect process changes. From the user inputs through to process equipment, the different components of automated wafer fabrication equipment work together to improve manufacturing outcomes.

An Intuitive User Interface Helps Operators Control the Process

A good user interface shows critical process variables and the status of necessary equipment. Operators can see how the process progresses and intervene to activate or shut down components if necessary. The interface can easily be updated when process requirements change or equipment is added. For fully automated stations, the process runs by itself after the operators select the sequence and set the initial conditions via the user interface.

Modutek automated stations use a touch screen with a graphical user interface (GUI). Operators see visual representations of the process and can control equipment from the screen. Because Modutek designs and programs the underlying software in-house, the company can easily change and update the GUI.

Automated Controllers Translate GUI Commands to Equipment Operation

Automation controls timed command sequences or keep process variables at the required set points. Sequences are programmed with Programmable Logic Controllers (PLCs) that output a sequence of commands when the operator issues the initial input. PLCs are programmed as a chain of outputs triggered by elapsed time or automated inputs. The chains are easy to program and change if needed.

Automation of process variables includes controllers for temperature, pressure, flow, or level. Modutek can integrate third-party controllers such as Omron or Allen Bradley for higher-level automation, such as machine control or special functions. This capability also allows Modutek to integrate its equipment into existing installations.

Data Logging Helps to Evaluate System Performance

When the Modutek automated stations are programmed to output key variables, the data can be assembled into reports helpful in evaluating performance and monitoring the program logic controls. The data can be collected over Ethernet and viewed remotely. Automated logs can be used to check values such as chemical use, output quantities, output yields, and chemical disposal details. Feedback from data logging is key to the optimization of the overall process.

Optional Equipment Interfaces Increase Application Flexibility

Modutek’s automated wafer fabrication equipment uses an optional interface that allows it to work with existing systems and components from other manufacturers. The SEMI Equipment Communications Standard/Generic Equipment Model (SECS/GEM) developed by the Semiconductor Equipment and Materials International (SEMI) organization governs the interaction of the software running the automated controllers and the semiconductor manufacturing equipment. Under the SECS/GEM standard, Modutek can customize its systems to meet customer requirements for updating its process lines or adding new equipment.

As a leading semiconductor equipment manufacturer, Modutek continuously innovates on equipment and automation. The company can supply individual pieces of equipment or provide turnkey installations. Modutek ensures its equipment meets customer needs and performs as expected in both cases.

Chemical Handling for Wet Processing Equipment

Posted on September 22, 2022 by Douglas Wagner

Chemical Handling for Wet Processing Equipment Because wet processing of silicon wafers uses different types of chemicals, semiconductor manufacturing facilities need chemical handling equipment to store, deliver and dispose of the chemicals. A complete chemical handling system takes care of all aspects of chemical use and ensures chemicals are delivered to the process when and where needed.

For corrosive, toxic, or flammable chemicals, safe handling is critical. Most of the chemicals used in wet processing can’t be released into the environment without additional treatment. Neutralizing dangerous chemicals on site or storing them in safe containers until they can be transported to a treatment facility must be documented to comply with local regulations.

Since chemicals are often dangerous to the employees operating wet processing systems, the chemical handling equipment has to be designed to minimize spills and reduce employee exposure to chemicals and their fumes. A comprehensive chemical handling system can improve workplace safety, reduce spills and waste, and make chemical processes more efficient.

Chemical Delivery Systems Provides Your Process the Chemicals It Needs

Chemical delivery systems store the chemicals safely and then deliver the right quantities, mixtures, and concentrations directly to the production line. The amount of chemicals delivered has to be precise and repeatable. Successful wet processing often depends on the right mixture or concentration because etching, stripping, and cleaning can vary with the amount of chemicals in the bath. When processing batches, the amounts delivered must be precisely the same for each batch. With continuous processing, the chemicals delivered can’t vary over time.

Modutek has a complete range of chemical delivery equipment, from high volume systems for large continuous production lines to small batch operations. Chemicals can be stored remotely in large totes with a load cell interface or in 55-gallon drums near the wet process station. Modutek’s SolidWorks Simulation Professional and SolidWorks Flow Simulation applications can calculate the exact quantities of chemicals required, and the chemical delivery systems provide precisely the calculated amounts. These systems ensure that chemical handling and process repeatability are excellent.

Modutek’s Collection Systems Remove Used Chemicals from Processing Stations

Once a wet process such as cleaning, etching, or stripping is complete, the used chemicals must be removed from the process stations and collected. Chemicals can be stored in safe containers and sent to a company specializing in neutralizing and disposing of hazardous chemicals, or they may be neutralized on-site.

To collect the chemicals from processing stations, chemical lift stations can pump the chemical waste from the process tank to a storage container. Chemical carts, also called pump carts or collection carts, can be moved near the process tanks to empty smaller amounts of chemicals. Storage can range from small carboys to large collection tanks. For small volumes, waste chemicals can be pumped directly into a five-gallon DOT-approved carboy for subsequent shipping to an off-site neutralization facility.

Acid Neutralization Systems Ensure Compliance with Environmental Standards

Many wet process semiconductor manufacturing steps use strong acids in their process baths. The used acids must be disposed of safely without risks to employees, the general public, or the environment. Local regulations specify how acid waste must be treated to ensure that disposal meets these requirements.

As regulatory compliance becomes more complex, the costs of disposing of chemical waste off-site are increasing. Modutek can provide self-contained acid neutralization systems that are inexpensive to operate. These systems add neutralizing chemicals to the acid waste and track chemical use, waste pH, and discharge quantities. The systems can generate documentation for regulatory compliance and safely dispose of the neutralized waste.

Modutek Offers In-House Expertise for Selecting Chemical Handling Equipment

Modutek can help customers choose the right chemical handling equipment for their facility. In-house experts at Modutek can recommend equipment from a full line of chemical handling systems. Modutek can customize equipment for special applications and ensure that the systems meet customer needs. Contact Modutek today for t a free consultation to discuss your chemical handling needs.

Easy to Install Wet Processing Equipment for R & D

Posted on September 8, 2022 by Douglas Wagner

Easy to Install Wet Processing Equipment for R&D When research labs need to produce semiconductor prototypes or small quantities for testing, it’s often too expensive to place an order with a wet process production line supplier or to purchase complete wet process stations. Modutek has developed innovative tabletop models that are less expensive than full-sized wet process manual stations and take up much less room. They support the most common wet process cleaning, etching, and stripping steps, and Modutek can customize the units for special applications. The new Modutek tabletop units are easy to install and ideal for small-quantity R&D applications.

Modutek’s Table Top Units Are Feature-Rich and Versatile

Modutek has designed its new tabletop wet processing units to satisfy various R&D needs. The Teflon tank models support acid process steps such as KOH etch and buffered oxide etch (BOE), while stainless steel models support solvent process steps such as solvent resist strip. Tanks are available for ambient temperature or temperature-controlled operation, and they can be static or re-circulating with a filter and an all-Teflon fluid path. The temperature-controlled models have precise controls with rapid and even heating of the bath. The tanks come with temperature and level alarms and a drain interlock.

The compact and simple design of the tanks makes them easy to use, and operators can quickly get excellent results. The standard units that support the most common wet process steps allow the production of many different types of semiconductors. Modutek can customize its tabletop units to support additional silicon wet etching processes as required.

Modutek’s Table Top Units Support KOH Etch

KOH etching is popular because it delivers precise results using a relatively safe process. As such, it is well-suited for tabletop R&D applications. The etch rate depends on potassium hydroxide (KOH) concentration and temperature in the process solution. The etch direction can also be influenced by the silicon lattice’s orientation and the silicon’s boron doping. Different etch control strategies allow operators to etch various shapes into the silicon wafer.

The concentration of KOH may vary from 10 percent to 50 percent, but it is usually at around 30 percent. The orientation of the silicon crystal lattice means that the etch rate is faster in one direction, and Boron doping stops the etch progress in the direction in which the boron is found. These control factors are determined by the design of the etch shapes before the start of the process. Once etching has begun, the temperature allows operators to further control the etch rate and influence the shapes of the etched cavities. Because KOH etches can be controlled in different ways, it is the etch process most commonly used in Modutek’s tabletop units.

Using Modutek’s Table Top Units for Sub-Ambient BOE Etch and Solvent Applications

BOE etching is used to etch patterns in silicon dioxide films or to remove such films from the silicon wafer surfaces. The etching solution contains hydrofluoric acid, and a low temperature reduces consumption. The units that support BOE are the circulating, filtered models that are also fitted with a heater/chiller. Sub-ambient operation down to 10 degrees centigrade is possible.

Solvents used in semiconductor manufacturing steps, such as solvent resist strip, require stainless steel tanks and special safety features. Solvents, such as acetone, are flammable, and Modutek’s tabletop units include measures to prevent fire and explosions. Modutek can customize solvent and acid tabletop units to support other wet-process applications and add special features as needed.

Modutek Can Provide Custom Units for R&D Applications

Modutek has extensive in-house experience designing and building silicon wet etching equipment. If you need equipment to support R&D functions, tabletop units are an excellent option that can be customized to support many wet-process applications. Contact Modutek for a free consultation to discuss your application requirements.