DRAM firm Nanya Technology has disclosed plans to invest up to NT$19.71 billion (US$659.1 million) in building additional 20nm process production capacity.

Nanya currently produces 35,000-36,000 12-inch wafers built using 20nm process technology a month, while its overall output has come to about 65,000 units, the Taiwan-based company disclosed. The additional new capacity will boost Nanya's 20nm process output by 10,000 units monthly.

Equipment move-in for new 20nm process production capacity will kick off between the end of 2018 and early 2019, said Nanya, adding that the additional new production capacity is expected to come online starting the second quarter of 2019.

Meanwhile, Nanya will continue to cut back 30nm process production capacity, the company noted. The cutback in 30nm chip output, coupled with 20nm process production ramp-up, will boost Nanya's total output to reach 73,000 units monthly, according to the DRAM chipmaker.

Nanya continued that the planned ramp-up of 20nm process production will have no impact on the company's overall bit supply this year, but will lead to a 15% increase in the bit supply for 2019.

Nanya originally set its capex target for 2018 at NT$11.5 billion. The capex will be revised to take this investment into account, said the company, adding that a revision will be disclosed when it is available.