A process that uses ozone with water or with a mild acid can clean, strip and etch wafers more rapidly and at lower cost than traditional processes. Modutek’s proprietary Advanced Ozone Cleaning Process eliminates the use of expensive chemicals while improving process performance and reducing environmentally harmful waste.

Modutek provides custom designed equipment to meet the specific requirements of customers and offers an ozone cleaning process as a solution for better silicon wafer manufacturing yields. The patented technology can replace traditional methods that use expensive chemicals and high temperatures with a room-temperature process that is environmentally friendly.

How the Ozone Cleaning Process Works

Modutek’s ozone cleaning process provides cleaner silicon wafers with reduced particle counts. For example, in Modutek’s DryZone solvent gradient dryer, the patented process rinses substrates with deionized water to remove water-miscible inorganic impurities and then exposes them to ozone in an ozone chamber. All traces of organic materials are converted to carbon dioxide. The resulting substrate surfaces are free from particles, moisture and trace organic materials and are stable hydrophilic surfaces.

For silicon wafers, the surfaces are Si-O terminated. If hydrophobic, Si-H terminated surfaces are required, a ten second post-ozone process can complete a conversion. Because the dryer uses reactive chemistries, it is particle-reducing rather than just particle-neutral.

In Modutek’s Organostrip process, wafers are exposed to an ozonated organic solvent at room temperature. The company’s technology produces very high ozone solubility in the liquid. The process results in a fast resist removal and it is compatible with all metals tested, including aluminum, copper, gold, tantalum, titanium and tungsten.

In all the Modutek ozone cleaning processes, the exact chemistry is delivered to the point of use in compact equipment that requires fewer steps and a smaller number of tanks than conventional wet benches. In contrast to traditional solvent processes, the ozone process solution has a longer useful lifespan and results in a more benign discharge. Available ozone processes include resist removal, surface preparation and final clean.

Advantages Compared to the Piranha Process

A commonly used conventional acid process is the sulfuric acid and hydrogen peroxide based Piranha process. Key advantages of the ozone cleaning process over the Piranha process include:

• More rapid processing: Batches of 100 wafers and a rate of 6 batches per hour per process tank allow silicon manufacturing facilities to achieve a higher throughput.
• Better compatibility: The Piranha process is not compatible with most metals while the Modutek ozone cleaning process has broad compatibility.
• Fewer particles: The number of particles left on wafers processed with the Modutek ozone cleaning systems is extremely low while Piranha leaves particles on the surfaces.
• Better safety: The Piranha process operates with highly corrosive chemicals heated to 130 degrees C. The Modutek ozone cleaning systems work at room temperature without harsh chemicals.
• Lower equipment cost: With fewer tanks and process steps, the Modutek ozone cleaning systems can cost substantially less than a Piranha installation
• Lower operating costs: Piranha process chemicals are up to twice as expensive as Modutek ozone cleaning chemicals. The total cost of ownership of a Piranha installation is much more than that of an ozone station.

Modutek can evaluate the needs of a silicon manufacturing facility and offer appropriate solutions. The new ozone technology increases manufacturing yields by reducing contaminants and can reduce overall costs. If you want a free consultation or quote on using Modutek’s ozone cleaning process to improve your manufacturing yields, call 866-803-1533 or email modutek@modutek.com.