Hermetically sealed container for large-sized precision sheet (semi-) product

摘要

A relatively light resinous hermetically sealed container for a large-sized precision sheet (semi-)product, such as a photomask, is provided so as to accommodate, support and transport the precision sheet (semi-)product safely and in an airtight manner. The hermetically sealed container includes a main body and a lid member respectively having peripheral flange portions abutted to each other so as to accommodate a precision sheet (semi-)product therein. Each of the main body and the lid member is formed as a vacuum or air-pressure formed thermoplastic resin sheet equipped with a reinforcing rib.