"ASML and Cymer have entered into a definitive agreement under which ASML will acquire all outstanding shares of Cymer in a cash-and-stock transaction currently valued at 1.95 billion euros ($2.55 billion," an ASML statement said.
ASML is one of the world's leading manufacturers of lithography systems used by the semiconductor industry to make integrated circuits and microchips while Cymer makes the light sources used in the lithography systems.
"The purpose of the acquisition of Cymer is to accelerate the development of Extreme Ultraviolet (EUV) semiconductor lithography technology," ASML said.
EUV is vital for manufacturing next-generation microchips with more power and efficiency at less cost, it added.
The acquisition was made possible by investments by customers Intel, TSMC and Samsung agreeing to contribute 1.38 billion euros to ASML's research and development.
Intel and Samsung also bought ASML shares worth 3.02 billion euros, while TSMC is expected to buy shares worth 838 million euros at the end of October.
Based in San Diego, California, Cymer employs 1,200 people, while ASML employs almost 8,000 people and is present in 16 countries.
Profits for ASML, founded in 1984 and based in Veldhoven in the southern Netherlands, were down in the third quarter to 275 million euros, compared to 355 million euros during the same period in 2011, the company said.
Turnover was stable at 1.22 billion euros compared to 1.46 billion euros a year earlier, in line with analysts' predictions.