The wafer manufacturing plant, built in 1997, is located in the Hsin-chu Science Park. It had previously produced both 8-inch and 12-inch wafers, but the 8-inch production line was sold off early last year.
Macronix will now take hold of a chip plant using 12-inch wafers, which has a maximum capacity of processing 20,000 a month.
The plant had previously been producing proprietary DRAMS for consumer applications, as well as foundry services for low-power and mobile DRAMs. It has also been making low-density Flash memory products.
ProMOS said that it needed to sell the chip plant in order to raise cash to upgrade a plant in central Taiwan to make advanced DRAM technologies. Now it will go on to produce 1Gb DDR3 using 63 nanoometer process technology from Elpida Memory.
According to Digitimes, Macronix is buying the fab in order to fabricate high-density and high-quality ROM and NOR flash products.
Miin Wu, CEO of Macronix, also said that the fab will deploy its 45 nanometer process technology and that buying it instead of building one shortens construction times and saves on costs.