ULSI Technology Trends toward 256K/1G DRAMs

Masahiro KASHIWAGI  

IEICE TRANSACTIONS on Electronics   Vol.E75-C    No.11    pp.1304-1312
Publication Date: 1992/11/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on LSI Memories)
ULSI,  DRAM,  technology trend,  SOI,  vertical processing,  

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If a perspective of the "256M/1G era" were to be made from this present, namely the last stage of the development of 64 M DRAMs, the process technologies will show a variety of progress. Some of them would remain only in the extension of the present ones, but others would show a fundamental change including their technological constitutions. The optical lithography will survive even the "256M/1G era" mainly with the innovations of mask technologies. The etching technologies will remain basically the same as the present ones, but will be much more refined. The studies on plasma/redical related surface reactions, however, will bring a variety of surface treatment technologies of new function. The interconnection technologies will encounter various kinds of difficulties both in materials and in processign, and mechanical processing will become one of ULSI processing technologies. The shallow junction technology will merge with the metallization and epitaxial growth technology. The thin dielectrics will approach a critical situation, and it might enhance the device structural change to three dimensional ones. Corresponding to this, the necessity of "vertical processing" will become larger. The bonding SOI technology might overcome these situations of increasing difficulties. On the other hand, the contamination control will be the base of these technology innovations and improvements, exploring a new technology field in addition to the conventional process technology fields.