An in-line MOSFET process with photomask fabrication process in a minimal fab

This paper describes a cleanroom-less device fabrication process of a minimal fab including an in-line photomask fabrication process, where half-inch wafers and half-inch photomasks are transferred in airtight containers and loaded into fabrication tools to prevent invasion of air-borne particles, gases and UV light from outside. Photomasks are fabricated using a maskless exposure system in the minimal fab. We have fabricated two types of MOSFET using the photomasks or maskless exposure system, and found that the two types of MOSFET have the almost same electric performance with the density of interface states (Dit) of the order of ID¹⁰ states/cm².