New Wafer Cleaning Technology Uses Frozen Gas Crystals

By Lisa a. Karter

Minneapolis, MN–A new technology for removing particulate and etch residue contamination on semiconductor wafers uses frozen argon/nitrogen gas crystals to clean 0.35-micron applications. FSI International, Inc. introduced the Aries Cryogenic Aerosol Cleaning System this month. Says Dan Syverson, technical marketing manager at FSI International: “The semiconductor manufacturing industry needs practical process equipment that reduces or eliminates chemical usage. The Aries tool meets this need as a solvent-free, water-free, back-end cleaning process.”

Based on a process developed by IBM, the Aries system removes multiple contamination types, including particles from deposition and residue from plasma eteching of metal, dielectric and polysilicon films, according to the company. The system cools argon/nitrogen gas into frozen crystals which are then sprayed across the wafer surface as the wafer passes under the system. As the crystals collide with the wafer surface, cryokinetic energy dislodges the contaminants. Then, the gas flow carries them away.

Maximum cleaning effectiveness is obtained using a specially designed array of jets that provide a wide, consistent distribution of the crystals across the wafer surface. Since argon and nitrogen are inert substances, the system eliminates the use of water, chemicals and solvents–as well as the need for chemical disposal.

According to FSI, the Aries Cleaning System is qualified for multiple applications on 0.35-micron and smaller production lines where particle and residue contamination is of critical concern. In post-etch applications, the system cleans metals, vias and oxide trenches. It also provides effective cleaning after the deposition of films. n