AN OFFER: ASML Holding NV, the biggest supplier of equipment to semiconductor manufacturers, has offered to buy Cymer Inc. of the U.S. for around $2.55 billion.
THE TECHNOLOGY: Cymer's technology makes focused beams of light. ASML uses such beams in machines to trace out the circuits of computer chips. ASML is a key supplier for the biggest chipmakers.
WHAT HAPPENS NEXT: The deal must be approved by regulators and Cymer shareholders.