TAINAN, Taiwan (Reuters) - Taiwan's UMC, the world's No.2 contract chip maker, said it will invest $8 billion in a 12-inch wafer plant in Taiwan, joining its peers in investing in high-end technology to meet demand for chips in fast-growing markets like mobile devices.

UMC held a ground-breaking ceremony for phase 5 and 6 production plants at its 12-inch wafer fab in Tainan, southern Taiwan, on Thursday, with a schedule to install machines at the plant in the second half of 2013. The company said it also plans to build phases 7 and 8.

Asian chipmakers, from Taiwan's top foundry maker TSMC to South Korean memory chip heavyweights Samsung Electronics and SK hynix, have eyed record investments and big acquisitions as they vie for a bigger share of the mobile market.

Early last month, Taiwan Semiconductor Manufacturing Co Ltd (TSMC) said it would invest more than T$350 billion ($11.9 billion) in advanced production technology at its Tainan plant over the coming years.

UMC said in May that it saw wafer shipments up 15 percent in the second quarter due to increasing orders on communication products and consumer electronics.

(Reporting by Argin Chang; Editing by)