South Korea's Hynix Semiconductor announced Sunday it has developed the world's highest-density memory chip using the thinnest process technology.

The new Hynix "DDR3 DRAM (dynamic random access memory)" chip adopts a technology that allows circuits inside to be just 40 nanometres apart -- a fifth thinner than at present.

A nanometre is one-billionth of a metre. The thinner the process is, the more cutting-edge the technology is for making the chips, which are widely used in computers and other electronic devices.

The new product is 50 percent more productive than existing chips as it requires less energy and costs less to produce than existing ones, Hynix said.

Mass production begins in the third quarter of this year, it said.

"Hynix has become the world's first to apply the 40-nanometre-class technology to the DDR3 DRAM chip successfully," Hynix spokesman Park Hyun said.

"The new chip development will help the company continue to lead the fast-changing memory chip market."

The memory chip industry has been hard hit by the global economic downturn, with Japan's Toshiba slashing production and key Taiwanese firms turning to the island's government for help as demand worldwide slumps.