Title :
Improved 0.12 /spl mu/m EB direct writing for Gbit DRAM fabrication
Author :
Nakajima, K. ; Yamashita, H. ; Kojima, Y. ; Tamura, T. ; Yamada, Y. ; Tokunaga, K. ; Ema, T. ; Kondoh, K. ; Onoda, N. ; Nozue, H.
Author_Institution :
ULSI Device Dev. Lab., NEC Corp., Sagamihara, Japan
Abstract :
Recently, electron beam (EB) direct writing has been put to practical use in advanced device fabrication, using for example, a cell projection (CP) method, a variably continuous moving stage, a high current density EB, and high speed deflector amplifier, all of which increase the writing throughput of the EB direct writing system. However, for EB direct writing to be used for advanced DRAMs, the following three techniques must each be improved and then combined successfully: (1) a resist process for obtaining reliable fine patterns, (2) a proximity effect correction for the CP method, and (3) CP EB direct writing (CP mask pattern selection) for improving the writing throughput. This article describes improved 0.12 /spl mu/m EB direct writing for Gbit DRAM fabrication.
Keywords :
DRAM chips; electron beam lithography; electron resists; integrated circuit technology; masks; proximity effect (lithography); 0.12 micron; DRAM fabrication; cell projection method; current density; electron beam direct writing; high speed deflector amplifier; mask pattern selection; proximity effect correction; resist process; throughput; variably continuous moving stage; Current density; Electron beams; Laboratories; National electric code; Optical device fabrication; Proximity effect; Random access memory; Resists; Throughput; Writing;
Conference_Titel :
VLSI Technology, 1998. Digest of Technical Papers. 1998 Symposium on
Conference_Location :
Honolulu, HI, USA
Print_ISBN :
0-7803-4770-6
DOI :
10.1109/VLSIT.1998.689188
