Reticle Design for Minimizing Multiproject Wafer Production Cost

摘要

Multiproject wafer (MPW) production cost is sensitive to how the chips are arranged in a reticle. In this paper, we propose a methodology for exploring the reticle floorplan design space to minimize MPW production cost. Experimental results show that our methodology often achieves double-digit cost savings. A study using MPW for volume production shows that the volume cutoff points range from a few thousand dice to tens of thousands of dice. Note to Practitioners-This paper proposes a methodology for minimizing MPW production cost via better chip placement in a reticle (called reticle floorplanning). Our methodology consists of an effective reticle floorplanning method, two simulated wafer dicing methods, two cost estimation models, and a procedure for calculating the cost assumed by each project. A design service company or a foundry can use our methodology to reduce MPW production cost and, thus, provides a more affordable and expedient service to its customers. The reticle floorplanning method and simulated wafer dicing methods employed here are the state-of-the-art. A practitioner should adapt these methods to other MPW problems such as dealing with multitechnology process, placing multiple instances of the same design in a reticle, etc. The cost models should also be revised accordingly. The cost data given in this paper should be used only for reference as mask tooling and wafer fabrication costs constantly change. The cost model proposed for calculating the production cost assumed by each project can serve as a basis for developing a fairer pricing model. The study of using MPW for low to medium-volume production is also very useful. It may help a customer deliver its product earlier to market using a low-cost fabrication program. The problem addressed in this paper becomes much simpler if the side-to-side wafer dicing constraint is removed.