Manual Minis Save Money for IBM

BY Susan English

Essex Junction, VT–To avoid retrofit costs, IBM Microelectronics is installing 240 manual minienvironments at its fabrication facilities in Vermont. Installation began after the company completed a study indicating the feasibility of maintaining a clean environment during manual loading/unloading of cassettes within a minienvironment.

“Their technique will be largely successful and save money and minimize downtime, otherwise they`d have to retrofit,” says George Fry, president of Aviso Micro Technology (Phoenix, AZ). Fry was uncertain whether this strategy would become a trend throughout the industry, however. “It seems like a very good approach to convert an existing facility, but I don`t know if it`s truly innovative.” IBM will present a technical report on the results of the strategy with an accompanying video at the Institute of Environmental Sciences` symposium this spring.

IBM`s new strategy lets an operator open up a box of wafers, take out the cassette, and then place it into the tool I/O. The strategy is the result of a lengthy study on cleanroom processing alternatives performed on the same tool sets in two separate fabricators. After the study was completed, Class 1,000/10,000 facilities were designed with tool-specific minienvironments for the manual loading of existing 200 mm cassettes and boxes. The first minienvironment installation began in the fall of 1994, and now over 100 “manual minis” are in IBM`s Vermont fabricators on approximately 28 different tool types. Another 140 are slated for construction.

Says Pete Muller, IBM`s chief engineer on the project: “We are a firm believer in minienvironments, because they allow you to degrade your basic facility. Instead of installing 100 percent HEPA coverage to make it a Class 1 or Class 10, we degraded the facility with enough HEPA coverage to maintain a Class 1,000/10,000 facility.”

“Manual minis” evolved from IBM`s lack of cleanroom space for additional tool capacity necessary to meet an increasing demand for 4- and 16-Mbit DRAMs, PowerPC microprocessors, and logic components. IBM opted for a common, back-end-of-the-line fabricator strategy to reduce the actual amount of clean space required. The manual minis would allow processing within one of the corners of two fabricators at IBM Burlington`s largest manufacturing facility.

So successful is the manual strategy, it is being used for all new tools ordered for both fabricators, according to IBM`s Muller, who says considerable cost savings have been realized. The strategy has challenged both tool suppliers and the IBM team to devise innovative ergonomic solutions. It has also led to a cooperative, sharing approach with another leading semiconductor manufacturer, which has introduced ergonomic solutions on its process tools. n