AMSTERDAM/PHOENIX, Arizona, Dec 5 (Reuters) - ASM International NV, a supplier to computer chip makers, will invest $300 million in expanding its research and development (R&D) operations in Arizona, the company's largest R&D hub, it said on Tuesday.

CEO Benjamin Loh said the decision was made in part due to ASM's current presence in Arizona, and in part due to the state's growing importance as a semiconductor manufacturing hub.

"Intel and TSMC are some of our biggest customers, so being able to collaborate with them on R&D benefits the whole semiconductor industry and supply chain," he told Reuters.

"We’re able to work directly with them on the next semiconductor innovations."

The company will build a new facility, including a laboratory and clean room, on a 21 acre (8.5 hectare) site in Scottsdale by 2026, adding 500 additional employees, from 800 in Arizona at present.

ASM, which is headquartered in Almere, Netherlands, has been the best performer in the AEX index of Dutch blue chip stocks this year, rising by 90% to 447.95 euros. That comes amid optimism the equipment it sells will play an increasing role in cutting edge chips made by TSMC of Taiwan.

ASM is the biggest seller of Atomic Layer Deposition (ALD) tools, used by chipmakers to form ultra-thin layers of material on silicon wafers. That step in the chipmaking process is becoming more crucial and repeated more often as chips become more complex.

Loh said ASM expected growth to ease in China in 2024 after a strong 2023, which saw Chinese chipmakers stock up on more "mature" equipment amid increasing export restrictions imposed by the U.S. and Dutch governments.

"Even though China has become a much more important market than in the past, for ASM the advanced technologies – such as the transition to 2nm gate-all-around device technologies - remain the most important driver," he said, referring to a generation of chips expected to begin arriving as early as next year.

ASM competes with Tokyo Electron of Japan, as well as Applied Materials and LAM Research of the U.S. (Reporting by Toby Sterling Editing by Mark Potter)