The Next Wafer Diameter Change

摘要

Many considerations must be taken into account for such a technially complex and financially significant decision. This article outlines some factors that tend to favor delaying the time of initiating the next wafer diameter and planning for the largest diameter wafer deemed possible at the time it is required. These factors are: 1. A 460-465 mm wafer (with process equipment initiated in ～2015, first year of production ～2019, and significant device production in ～2021/22) seems optimum for square die arrays <25 mm on a side (including the street). 2. A 480-515 mm wafer provides more usable area and permits more die >25 mm on a side. However, it offers more technical and economic challenges. 3. The time for doubling the complexity of the most advanced devices needed by the end users seems to be increasing from its historic 18-24 month period. 4. Delaying the next diameter change and targeting a somewhat larger diameter provides more time to amortize the investment already made in 300 mm capability. 5. The 300 mm transition demonstrated that standardization, planning and cooperation can minimize the difficulties associated with a wafer diameter change. Now (2004-2010) is the time to have a vigorous discussion about the next wafer diameter and when must it be implemented.