Motorola faces ESD-induced lockups…Ortner and Shuttleworth join forces…Praxair and Vacuum Instrument to provide leak testing…DuPont increases capacity for Zyron 116 electronic gas…AmeriNet and Fisher Hamilton sign national agreement.
AUSTIN, TX–Motorola Faces ESD-induced Lockups
Even with ionization equipment installed, companies can still suffer from static problems. At a state-of-the-art Motorola fab in Austin, ESD was behind the mysterious lockup of stepper equipment. Even though ionization equipment had been installed, it took a team of fab personnel, the ionization equipment supplier, the stepper supplier, and the ceiling vendor to track down and solve the problem.
The team undertook a study of the fab to find common sources of EMI that resulted from ESD, according to a paper presented at the 1999 EOS/ESD symposium held in September in Orlando, FL. The event was sponsored by the ESD Association in cooperation with the IEEE. Roderick Ford-Smith of Ion Systems in Berkeley, CA and Harold Barnett et. al. of Motorola, described the EMI audit they conducted in their paper.
According to officials, Motorola outfits its facilities with the lastest products and techniques. However not only did the Austin fab have a strict guideline for ESD and an air ionization spec, but it contained wafer processing tools of increasing sophistication that had been added continually since the long ago installation of the first ionization equipment. The ceiling was fully ionized with synchronized pulsed DC bipolar ionizers. Facility engineers had grounded all table tops and racks using conventional methods. Yet the steppers were experiencing unexplained stoppages at the rate of three per stepper per week, and the error message was undecipherable error.
The stepper manufacturer was unable to pinpoint the problem and maintained that his tools were grounded and hardened to meet the fab's RFI spec. The peak value of the transient EMI from the discharges was well in excess of the Motorola spec and the stepper manufacturer's immunity to EMI.
The staff conducted a test for static problems by temporarily removing ceiling diffuser panels from an area of the cleanroom. Prior to the removal, the EMI locator was in sync with the pulsing of the air ionization system. As they removed diffuser panels, the EMI locator gradually registered fewer and fewer EMI events, but the occurences never went away entirely. The staff removed some 64 panels covering an area 32 x 16 feet. There were occasional EMI bursts, but not as frequently or of the magnitude recorded earlier.
Operators eliminated EMI by adding a more direct ground connection to the ceiling grid-installing ionization equipment without grounding the isolated conductors that caused the problems with the steppers. For a period of seven weeks following these corrective actions, the incidence of lockup was zero.
This incident showed that as tool sophistication increases, operating frequency ranges of microprocessors seem to have the same frequency range as typical ESD events. According to the authors, these effects show the importance of implementing an ESD prevention program. Such a program begins with grounding everything possible. The second step is to eliminate all nonessential insulators from the work area. Next, provide ionization to neutralize charges on the process-essential insulators and isolated conductors in the work area. Ensure that no isolated conductors have been left in proximity to a ceiling-mounted ionizer. Finally, periodically train and retrain fab personnel to raise their ESD consciousness. —GDM
DRESDEN, GERMANY–Ortner and Shuttleworth Join Forces for Cleanrooms
Ortner and cleanroom conveyor system manufacturer Shuttleworth announced recently a joint effort to automate cassette transport in wafer fab applications. As general contractor and system integrator, Ortner Cleanroom Logistic System GmbH will be the exclusive European distributor of Shuttleworth's zone control conveyor systems for the wafer fab sector. The companies will join forces to realize and optimize logistics projects in new fabs and for rebuilds. Shuttleworth Europe Ltd. is based in Ghent, Belgium.—LB
DANBURY, CT–Praxair and Vacuum Instrument to Provide Leak Testing
Helium supplier Praxair Inc. has entered into a marketing agreement with Vacuum Instrument Corp., a provider of advanced leak detection equipment, to supply non-destructive leak testing to the automotive and HVAC industry segments. The companies will also develop uses for helium leak testing in other industries.—LB
DEEPWATER, NJ–DuPont Increases Capacity for Zyron 116 Electronic Gas
To ensure an ongoing, reliable supply of the electronics gas Zyron 116 (C2F6), DuPont has increased capacity by about 500,000 pounds per year at its plant in Deepwater, NJ. The expansion was achieved by optimizing existing operations at the facility.—LB
TWO RIVERS, WI–AmeriNet and Fisher Hamilton Sign National Agreement
AmeriNet, a membership-based care group purchasing organization (GPO), and Fisher Hamilton, a Two Rivers, WI-based manufacturer of laboratory workstations and fume hoods, have announced an agreement to provide Fisher Hamilton laboratory products through Fisher Healthcare and the Fisher Hamilton national dealer network.—LB