How Advanced Ozone Cleaning Reduces Chemical and Solvent Usage

As environmental concerns mount and regulatory compliance becomes more difficult, companies that reduce the use of hazardous chemicals and solvents will have a competitive advantage. In addition to reducing costs, the use of fewer corrosive chemicals improves workplace safety and can lead to better semiconductor manufacturing facility performance. Modutek’s patented advanced ozone cleaning process saves money and reduces the contaminating particle count on wafer surfaces. Depending on process requirements, ozone cleaning can out-perform traditional wafer cleaning with harsh chemicals. Modutek’s ozone cleaning process is compact, fast, and safe.

Advanced Ozone Cleaning Converts Organic Impurities to Carbon Dioxide

Modutek has developed the Cold Strip sub ambient process that operates with deionized water and the Organostrip process that uses a mild acid at room temperature for photo resist strip. This also eliminates the use of NMP solvent base strippers. Both use ozone to clean organic contaminants from wafer surfaces and both leave harmless residues that allow for disposal without special neutralizing procedures.

The Cold Strip Advanced Ozone Cleaning Process operates at four to ten degrees centigrade and uses deionized water to strip silicon wafers of water-soluble inorganic impurities. After the wafers are rinsed with deionized water, ozone is introduced into the chamber. The ozone reacts with the remaining organic impurities and converts them to carbon dioxide. Particle contamination is reduced as well because the ozone reacts with organic particles. Wafers are more effectively cleaned with a reduced particle count.

In the Organostrip process, wafers are rinsed with a solution of a mild acid and ozone at room temperature. The acid has a high ozone solubility that lets the ozonated solution remove organic compounds from the wafer surfaces quickly and completely. The process is compatible with metals such as gold, copper, and aluminum, and the waste products of the Organostrip process are not hazardous.

Modutek uses its DryZone solvent gradient dryer for the Advanced Ozone Cleaning Process that the company developed to address customer concerns. Customers experienced high particle counts and issues with the use of hazardous chemicals, including their effect on the environment. The developed process successfully addresses these issues and delivers effective wafer cleaning.

Modutek’s Advanced Ozone Cleaning Process Provides Substantial Benefits

Modutek developed the Advanced Ozone Cleaning Process to address specific customer concerns, but the Cold Strip and Organostrip processes also improve wafer cleaning and facility operations. The benefits of using ozone cleaning include the following:

  • Reduced cost for process chemicals. The acids used in a traditional wafer cleaning process, such as sulfuric or hydrochloric acids, are expensive, and the cleaning processes such as Piranha clean use substantial volumes of chemicals. Ozone and the mild acids or solvents used in ozone clean are less expensive and the solutions last longer.
  • Reduced cost for chemical handling. The storage, delivery, and disposal of hazardous chemicals used for traditional wafer cleaning is expensive. The handling of ozone and the mild chemicals used for ozone cleaning requires no special measures.
  • Improved workplace safety. The chemical baths used for traditional wafer cleaning often operate at high temperatures and they can be dangerous. The ozone cleaning process chemicals are safe and the operation is done at sub ambient or at room temperature.
  • Higher throughput. Advanced ozone cleaning takes less time than traditional cleaning methods.
  • Improved yields. Ozone cleaning reduces particle counts and results in higher output quality with fewer product defects.

Modutek’s Continued Process Improvement Delivers Innovative Solutions for Customers

Modutek works closely with customers to identify new concerns and solve existing processing problems. Using extensive in-house experience and expertise in wet process technology allows Modutek to provide innovative solutions to meet customer needs. New wet process steps such as Advanced Ozone Cleaning can help customers improve semiconductor manufacturing facility performance and increase profitability.

Using the Advanced Ozone Cleaning Process to Improve Wafer Yields

Using the Advanced Ozone Cleaning Process to Improve Wafer YieldsTwo key goals for semiconductor manufacturers are to increase process yields and to reduce chemical usage. Wet process semiconductor manufacturing is sensitive to wafer contamination by microscopic particles that increase final product rejection rates and reduce output quality. The ozone cleaning process can reduce particle counts and improve wafer yields by reducing the number of defective products. At the same time, cleaning organic contaminants from the wafer with ozone reduces the use of expensive and toxic chemicals. Modutek’s Advanced Ozone Cleaning Process allows semiconductor manufacturing facilities to increase throughput and output quality while reducing operating costs.

How Advanced Ozone Cleaning Improves Wet Process Line Performance

Modutek’s Advanced Ozone Cleaning Process uses ozone to remove organic contaminants from the surfaces of silicon wafers during wet bench processing. Ozone is used with either room temperature acidic acid or chilled DI water to clean wafers without aggressive chemicals. In addition to saving money due to reduced use of chemicals, ozone cleaning takes less space and is faster than many chemical-based wet bench processes.

Ozone cleaning takes place in Modutek’s DryZone System. Modutek has developed the Coldstrip sub ambient process and the Organostrip process that operates at room temperature. Both ozone cleaning processes deliver reduced particle counts and increased yields.

The Coldstrip process operates at four to ten degrees centigrade and introduces ozone into the ozone chamber after the wafers have been rinsed with de-ionized water. The rinsing removes non-organic contamination while the ozone combines with the carbon of the organic contaminants to produce carbon dioxide. After completion of the Coldstrip process, the wafers are clean and almost particle-free.

In the Organostrip process, the wafers are rinsed with acidic acid containing ozone. The acidic acid used has extremely high ozone solubility and the high ozone level producing produces rapid decomposition and oxidation. The ambient temperature process eliminates the use of toxic chemicals and the process waste products are harmless.

The Modutek Advanced Ozone Cleaning Process Improves Performance While Saving Money

Modutek developed the Advanced Ozone Cleaning Process to achieve low particle counts and to reduce the use of harmful chemicals. Reduced particle counts are needed for the more compact architecture of modern semiconductors where a single particle can cause defects or lower component quality. Reduced use of chemicals is mandated by increasingly strict environmental regulations while chemical purchase, storage and disposal costs continue to rise. The patented Modutek Advanced Ozone Cleaning Process successfully addresses these issues.

Specific benefits from using the ozone cleaning process include the following:

  • Better wafer yields due to lower particle count
  • Savings from reduced use of chemicals
  • Compatibility with metal films
  • Safer work environment due to absence of toxic substances
  • More environmentally friendly operations
  • Space saving due to more compact equipment
  • No toxic waste disposal issues

Modutek’s Advanced Ozone Cleaning Process increases throughput due to shorter cleaning times and higher yields while cost savings due to reduced use of chemicals are substantial. Semiconductor manufacturers can improve the overall performance of their facility by incorporating Modutek’s DryZone cleaning stations in their wet process lines.

Modutek Can Help Customers with Innovative Solutions

The Advanced Ozone Cleaning Process is one example of Modutek’s initiatives to improve the performance of wet process technology stations and help customers address common problems. The patented process solves issues with current semiconductor manufacturing and helps customers with product quality and with their bottom line.

With Modutek’s emphasis on customer service and on working with customers to improve wet process technology, the company continues to be a leader among semiconductor equipment manufacturers. Customers can rely on Modutek to supply the equipment they need and to provide the support ensuring the equipment meets or exceeds performance expectations.