The upgrade is to install Micron’s 13nm DRAM process.
The Hiroshima fab used to be owned by Elpida which Micron bought for $2.5 billion in 2013.
The Elpida acquisition gave Micron a stronger position in mobile DRAM.
Elpida had two fabs in Hiroshima, one which it took over from NEC in 2003 and one which it built itself in 2005. Both are 300mm.
Last December, Micron bought out the 67% of Taiwan DRAM-maker Inotera which it didn’t already own.
Last month it appointed Sanjay Mehrotra, founder and CEO of SanDisk, to be Micron’s CEO.