TOKYO, April 8 (Reuters) - Japan's Shin-Etsu Chemical Co plans to spend about 83 billion yen ($546 million) to build a microchip materials plant in Japan by 2026, its first domestic manufacturing facility in 56 years, the Nikkei business daily said on Monday without citing sources.

($1 = 151.8900 yen) (Reporting by Kiyoshi Takenaka Editing by David Goodman )