SEMI publishes standard for 450-mm wafers

LONDON — The SEMI industry organization has published its first standard covering the use of 450-mm diameter wafers in a production environment; which may be seen as a sign that the industry is starting to pick up the pace in adding a larger wafer size above the current maximum at 300-mm.

The E154 publication standardizes the interface dimensions and load ports for the 450-mm FOUP (front opening unified pod) which is the enclosure designed to hold silicon wafers in a controlled environment for transfer between processing or measurement tools. Loading and unloading is assumed to take place in semi-automated and automated mode using a person-guided vehicle or an overhead hoist vehicle.

The standard was approved for publication on Dec. 16, 2009 and became available www.semi.org in February 2010.

However, E154 is not the first 450-mm wafer standard from SEMI. The M74 specification for mechanical handling of 450-mm diameter polished wafers was announced on Oct. 16, 2008. That specification covers dimensional requirements for 450-mm diameter polished silicon wafers.

However, M74 is aimed at R&D and specifically is not intended to specify wafers used in process development or for technology-specific circuit-quality applications. This document is expected to be superseded by a process development wafer specification, a prime wafer specification and technology-specific guidelines for circuit-quality wafers.