Korea's SK has acquired a controlling stake in silicon wafer manufacturer LG Siltron for 620 billion won ($531 million).

Announced earlier this week by SK Holdings, the holding company of SK Group, the acquisition is expected to rev up vertical integration of Sk's semiconductor business surrounding SK hynix, the world's second-largest memory chipmaker.

SK has established its business portfolio regarding materials for semiconductor production after acquiring Hynix Semiconductor in 2011.

Ahead of the Siltron deal, the group bought OCI Materials, a local manufacturer of special gases used in making chips, LCDs and solar panels, for 482 billion won in 2015. It also took over SK Airgas, an industrial gas manufacturer.

In addition, SK hynix is reportedly considering a joint venture with Seagate as part of its plan to bolster its presence in the NAND market.

The chipmaker also plans to invest 2.2 trillion won to build a plant in Cheongju, North Chungcheong Province, by 2019 to meet growing demand for more storage in mobile devices and computers.

Competition between local semiconductor vendors SK and Samsung is heating up. Samsung Electronics, the world's top memory chipmaker plans to fast shift to 10-nano DRAM chips while increasing investments for product diversification and expanding investments in the non-memory chip sector.

Samsung is also expected to focus more on NAND flash chips as its market is expected to see higher growth this year.

Along with its plants in Giheung, Gyeonggi Province, and Xian, China, Samsung will open a new chip plant in Pyeongtaek midway through the year.

In the non-memory chip area, Samsung will supply its Exynos chipsets for an in-vehicle infotainment system to Audi, allowing drivers to enjoy a variety of audio, video and navigation services through GPS.