Shares of semiconductor equipment makers surged Tuesday after Samsung Electronics and SK Hynix unveiled plans to invest 800 trillion won, about $518 billion, in a new chipmaking hub in southwestern South Korea.

ASML closed 6.8% higher in Amsterdam at a fresh record. In New York afternoon trading, Applied Materials gained about 5.5%, while KLA climbed nearly 9%.

Samsung and SK Hynix each plan to construct two factories under the project, which forms part of South Korea’s effort to expand its artificial intelligence infrastructure and double domestic memory chip production over the next five years.

The planned expansion has strengthened expectations that chipmakers will accelerate purchases of the lithography, deposition and inspection systems required to equip the new facilities.

The gains extend a historic run for semiconductor stocks. The Philadelphia Semiconductor Index nearly doubled during the first half of the year and gained more than 86% in the second quarter, its strongest quarterly performance on record.

The rally has remained volatile. The chip index lost 7.9% last week, its worst weekly performance since early April, before rebounding as investors returned to companies exposed to artificial intelligence infrastructure spending.

Analysts have also raised their expectations for the equipment market. Susquehanna analyst Mehdi Hosseini increased his price targets for Applied Materials and Lam Research, citing stronger industry demand, while other estimates place annual wafer fabrication equipment spending at as much as $250 billion by 2028.

The next test for the sector will come during July earnings. ASML is scheduled to report on July 15, followed by Taiwan Semiconductor Manufacturing on July 16, when investors will be watching for new factory spending guidance