Small spaces create new process technologies in minimal fab
Sommawan KHUMPUANG1,2, Yuuki ISHIDA1,2, Shinichi IKEDA1,2, Shiro HARA1,2
We have developed new process technologies for small process spaces in Minimal Fab for low-volume device production. In this work, we summarize useful processes in Minimal Fab that have not been employed in conventional fabs. For example, a small wafer has a strong surface tension at the wafer edge that keeps a volume of liquid on it, which has led us to the development of a spin droplet cleaning process. Beam-type technologies scan over a small wafer area with a short beam scanning time letting us develop a maskless UV exposure system, with a nozzle micro-plasma while laser heating without scanning is uniformly applied over the wafer. In plasma etching, the plasma size is much smaller than the chamber size and is isolated far from the chamber wall, therefore the process is less contaminated. Moreover, the small chamber lets us realize high-speed etching with a cycle time of 2 seconds in an alternative gas feeding and time-multiplexing process. In the transistor manufacturing processes, using our developed clean-localized wafer transfer system, we have found that the density of the interface states of MOS capacitors is related to the relative humidity in the atmosphere.
- 1 National Institute of Advanced Industrial Science and Technology
- 2 Minimal Fab General Incorporated Association