<title>Pelliclizing technology</title>

Abstract

Four years ago, we started pelliclization on both sides of masks using a pilot plant and shipped them for our customers for the first time. At that time, there were few pellicles that were usable, and we were only inspecting for particles. But recently, we understand the pellicle market in Japan to be approximately 20,000 pieces per month. It's convenient to the customer for them not to have to worry about the cleaning their masks during use because of particles being added to the plates. Therefore we believe the need for pelliclized mask will increase rapidly in the near future. On the other hand, specifications for 4M or 16M DRAM masks are very critical as shown in Table-1 and our customers are requiring the same particle size specifications under the pellicle film as the chrome defects on the surface of the mask. It's much easier to order such a mask than to make one evaluating a wide variety of pellicles and have developed adequate methods of mask cleaning and inspection.