From Microchip Fabrication: A Practical Guide to Semiconductor Processing, Fifth Edition

Cleanroom Maintenance

Regular maintenance of the cleanroom is essential. The cleaning personnel must wear the same garments as the operators. Cleanroom cleaners and applicators, including mops, must be carefully specified. Normal household cleaners are far too dirty for use in cleanrooms. Special care must be taken when using vacuum cleaners. Special cleanroom vacuums with HEPA filtered exhausts are available. Many cleanrooms will have built-in vacuum systems to minimize dirt generation during cleaning.

The wipe-down of process stations is done with special wipes made from non-shedding polyester or nylon, prewashed to reduce contamination. Some are prewetted with an isopropyl alcohol and DI water solution, which provides convenience and eliminates secondary contamination from spraying cleaners in the cleanroom.27

The wiping procedure is critical. Wall surfaces should be wiped from top to bottom and deck surfaces from back to front. Cleaning chemicals in spray bottle, if used, should be sprayed into wipes, not onto the surfaces. This prevents overspray onto the wafers and equipment. Cleanroom cleaning has, itself, become a critical supporting operation. Many fabs use outside certification services24 to identify and document cleanliness levels, practices, documentation, and control procedures. Certification standards for cleanroom maintenance schedules is identified in the ISO Global Cleanroon Standards (ISO 14644-2).

Copper metallization has become the metal of choice for advanced ULSI devices. While the copper has many advantages (see Chapter 13), there is a serious downside. Copper contamination inside a silicon wafer raises havoc with the electrical operation of the component devices. Isolating the copper processing areas...

Products & Services
Cleanrooms are contamination-free environments where high-tech manufacturing and assembly take place.
Vacuum Cleaners
Vacuum cleaners are capable of picking up large quantities of material and/or liquids. They can be portable devices or part of a central vacuum system.
Cleanroom Supplies and Accessories
Cleanroom supplies and accessories include garments, flooring, lighting, ducting and other items used in cleanroom settings.
Air Showers
Air showers use jets of filtered air to clean particle contamination from personnel and equipment during entry into a cleanroom environment.
Aerosol Cleaners and Contact Cleaners
Aerosol cleaners and contact cleaners are dispensed as a fine-droplet spray. Contact cleaners are used widely in the mission-critical cleaning of electronic, electrical, and fiber optic connectors.

Topics of Interest

Wafer Surface Cleaning Clean wafers are essential at all stages of the fabrication process but are especially necessary before any of the operations are performed at high temperature. Up to 20...

Richard V. Pavlotsky Pavlotsky and Associates Danville, California Stephen C. Beck LeChase Holley, New York 38.1 INTRODUCTION Today s manufacturing cleanroom is a complex organism whose purpose is to...

Cleanroom Construction Selection of the clean air strategy is the first step in the design of a cleanroom. Every cleanroom is a trade-off between cleanliness and cost. Whatever the final design,...

Review Questions State the class number required for VLSI processing and ULSI processing. List three techniques used to keep contamination out of a cleanroom. Draw a cross section of a "total"...

Cleanroom gloves are critical for contamination control in the semiconductor, flat-panel display, disk-drive, and other high-technology industries. They are among the most important and expensive of...