Arch Microelectronic Materials' Advanced Photoresist Business Wins a Quality Supplier Award from National Semiconductor.

NORWALK, Conn. -- Arch Microelectronic Materials' advanced photoresist business in North Kingstown, Rhode Island, recently won a Quest for Gold (QFG) quality award from National Semiconductor Corporation. The award presented to Arch (NYSE: ARJ) was based on superior ratings for its performance during 2003 in the categories of technology, total cost, quality and service.

The Bronze QFG award was primarily awarded for the advanced photoresists and ancillary products provided by Arch to the National Semiconductor manufacturing plants in South Portland, Maine; Arlington, Texas; and Greenock, Scotland. Headquartered in Santa Clara, California, National Semiconductor Corporation is one of the world's leading manufacturers of analog semiconductor devices.

"We are delighted to be one of a select group of material suppliers to have received a Quest for Gold award from National Semiconductor," said Philippe Gouby, President of Arch Microelectronic Materials. "This is a strong validation of Arch's proven ability to provide National Semiconductor with high-performance, cost-effective photoresists and ancillary products and technical support."

Mr. Gouby added that the intensive quality-control systems that Arch Microelectronic Materials' facilities have developed to earn their QS 9000 quality certificates and ISO 14001 environmental quality certificates played a significant role in Arch's ability to win a Quest for Gold award. The QFG technology category, for example, requires a supplier to excel at meeting National Semiconductor's current and future product needs, providing them with effective technical assistance and having proactive systems to drive superior performance in the areas of the environment, health and safety.

A business segment of Arch Chemicals, Inc., Arch Microelectronic Materials supplies global semiconductor and flat panel display manufacturers with photoresists, polyimides, formulated products, thin film systems and chemical management services.

Headquartered in Norwalk, Connecticut, Arch Chemicals is a global specialty chemicals company with more than $1 billion in annual sales. Arch and its subsidiaries have leadership positions in three business segments -- Treatment Products, Microelectronic Materials and Performance Products -- and they serve leading customers in these markets with forward-looking solutions to meet their chemical needs. Together with its subsidiaries, Arch has approximately 3,300 employees and manufacturing and customer-support facilities in North and South America, Europe, Asia and Africa.