Micron intends to invest up to $100 billion over the next 20-plus years to construct the 1,400-acre (570-hectare) campus in Clay, New York, with $20 billion planned by 2030 .Micron plans to start building next year, with two of the four planned 600,000-square-foot (56,000 square-meter) fabrication units open by 2029, according to the filing .