Why Megasonic Cleaning is Essential for Silicon Wafer Processing

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 Enhanced Automation Equipment Provides Precision Parts Cleaning

How Enhanced Automation Equipment Provides Precision Parts CleaningEnhanced 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.