Japan will tighten rules for the export of high-tech materials to South Korea
The row between Japan and South Korea erupted in October last year and was triggered by a South Korean Supreme Court ruling obliging Japan's Nippon Steel to pay Koreans for their forced labor during World War II.
However, Japan claims that the forced labor problem was completely resolved in 1965, when the two countries restored diplomatic ties, and denounced the decision as "unthinkable."
Materials to be restricted are fluorinated polyimide, which is used in smartphone displays, resist and high-purity hydrogen fluoride (HF), which is used as an etching gas in semiconductor fabrication, the document says.
A resist is a thin layer used to transfer a circuit design onto a semiconductor substrate. High purity HF is used when etching silicon materials.
Japan will end preferential treatment for these three materials for South Korea, meaning that Japanese exporters will need to apply for an export permit every time they want to go to South Korea, which takes about 90 days, the document says.
Japan produces about 90% fluoropolyimide and resist worldwide, as well as about 70% pickling gas, making it difficult for chip makers Samsung and LG in South Korea to find alternatives, the document explains.