keywords: toppan photomasks dupont japan yen
text: Japan's Toppan to Buy DuPont Photomasks  TOKYO (Reuters) - Japan's Toppan Printing Co. Ltd. said on  Tuesday it would buy DuPont Photomasks Inc., a U.S.-based maker  of glass plates used in chip production, for 71 billion yen  (\$640 million).