by Dr. Paula Doe, Contributing Editor, Solid State Technology
E-Shuttle president Haruo Tsuchikawa reports his company aims to bring down ASIC development costs by using e-beam direct write instead of masks for some critical layers in its prototyping service for 65nm chips starting this month (October 2007). The joint venture of Fujitsu Ltd. and Advantest Corp. installed a 300mm e-beam writer from Advantest in Fujitsu’s Mie fab in February.
Tsuchikawa told SST partner Nikkei Microdevices that Fujitsu’s current 90nm shuttle service cuts customer costs for test chips by at least 20% by putting multiple different chip designs on one shared wafer, but eliminating some masks by using direct write instead should allow another 10%-20% savings initially, and perhaps as much as 30%-40% in the future. Directly writing the pattern also makes design re-spins easier, since new masks don’t have to be made.
While the conventional shuttle service will continue, e-beam direct write will increasingly become the core technology from 65nm, said Tsuchikawa. E-beam will initially be used for some narrow-pitch lower-level interconnect layers, and then will start to be used for transistor layers about six months later. Eliminating the long wait for masks for transistor levels would considerably speed up turnaround. Wide-pitch upper-level interconnect layers will continue to be made with the relatively inexpensive masks. The venture aims to start offering 90nm prototyping in February 2008, and 45nm in April 2009. Tsuchikawa reported the company is already in discussions with customers on several dozen different types of chips.
Shuttle customers using direct write on some layers will supply standard GDSII data, and get back 30 chips, just as before. Fujitsu aims for e-Shuttle to attract more outside customers to its foundry business — its shuttle service is now used 90% by Fujitsu projects, but the target is a 50%-50% mix. The e-Shuttle Web site credits its direct write rapid prototyping capability in part for attracting eASIC’s business to Fujitsu’s foundry. — P.D.