Toshiba and SanDisk on Tuesday celebrated the opening of the second phase of the No. 5 semiconductor fabrication facility (Fab 5) and the start of construction of the new No. 2 fabrication facility (Fab 2) at Yokkaichi Operations, Toshiba's NAND Flash memory plant in Mie prefecture, Japan. Toshiba started construction of the second phase of Fab 5 in August 2013, and Toshiba and SanDisk have overseen installation of production equipment in the expanded facility since July this year. Production in phase 2 began at the start of this month, with 15nm NAND flash memory process technology. The two companies announced deployment of this jointly developed 15nm NAND flash process in April this year, with initial production in part of Fab 5 phase 1, and now target conversion of the remaining capacity in phase 1 to the new process technology.

Toshiba is constructing the New Fab 2 to secure space to convert Toshiba and SanDisk's current 2D NAND capacity to 3D NAND, with expected readiness for production in 2016.

The Japanese company will maintain an annual investment of around 200 billion yen ($1.9 billion) into its chip business beyond the current business year, Chief Executive Hisao Tanaka said on Tuesday.

Toshiba is curently competing with Korean rival Samsung Electronics in the NAND flash memory chip market.