AMSTERDAM, April 16 (Reuters) - ASML, the world's biggest manufacturer of tools for semiconductor chip makers, altered its sales forecast for the first half, saying it now expects to sell 3 billion euros ($4.15 billion) worth of products including extreme ultraviolet (EUV) systems.
The Veldhoven-based company had previously forecast sales of 3 billion for the first half excluding sales of EUV systems. It said slower sales in the second-quarter had led to the revision.
"Sales in the second quarter are ... expected to be affected by adjustments of system demand from some logic customers," it said in its earnings statement.
ASML supplies most of the world's major chip manufacturers, including Samsung Electronics Co. Ltd, Intel Corp and Taiwan Semiconductor Manufacturing Co Ltd (TSMC) , and acts as a leading indicator of their fortunes.
ASML has invested heavily in EUV technology, buying Cymer Inc, a supplier of lithography light sources used to make chips, for $2.5 billion in Oct. 2012 to speed up development of the technology after it suffered a string of setbacks.
Around 80 percent of ASML's products go to customers in Asia. The rest are sold to clients in the United States and Europe.
ASML reported a first quarter net profit of 249 million euros, on sales of 1.4 billion euros, roughly in line with forecasts.
ASML was expected to post first-quarter sales of 1.4 billion euros and a profit of 228 million euros, according to the average of 11 analysts polled by Reuters.
Investors have looked at ASML's investment in EUV technology to gauge future orders and the ability to continue to continue to produce smaller computer chips.
For the second quarter of this year, ASML said it expects sales of 1.6 billion euros, including EUV sales. ($1 = 0.7234 Euros)
(Reporting By Anthony Deutsch; Editing by Miral Fahmy)