| Popis: |
Deep UV lithography is an enabling technology for the fabrication of 64 megabit DRAM class devices. Wafer steppers operating at 248 nm currently provide both the resolution and the overlay capability to meet the stringent reguirements imposed by next generation memory device design. To demonstrate this, a prototype 64 megabit DRAM has been produced using exclusively DUV lithography. We chose two resist processes: a single level negative tone resist for noncritical levels and a surface imaging resist for critical levels. We show the process capability results for each resist approach, and discuss the advantages and disadvantages of each. We also discuss outstanding issues relating to implementation of deep UV lithography, including equipment reliability, resist performance and availability, and process throughput |
