Cree Inc. of Durham, N.C., a maker of semiconductors and devices for solid-state lighting, power and communications products, announced that it has signed a five-year supply agreement with LED manufacturer Seoul Semiconductor Co. Ltd. of Korea. Under the agreement, Seoul Semiconductor will buy at least $40 million in LED products from Cree during the first five quarters, with additional purchases negotiated annually. The parties said the agreement could be extended up to another five years if certain sales conditions are met. Cree and Seoul Semiconductor also have agreed to cross-license certain patent rights relating to white LED technologies.