Title :
Giga-bit scale DRAM cell with new simple Ru/(Ba,Sr)TiO3/Ru stacked capacitors using X-ray lithography
Author :
Nishioka, Y. ; Shiozawa, K. ; Oishi, T. ; Kanamoto, K. ; Tokuda, Y. ; Sumitani, H. ; Aya, S. ; Yabe, H. ; Itoga, K. ; Hifumi, T. ; Marumoto, K. ; Kuroiwa, T. ; Kawahara, T. ; Nishikawa, K. ; Oomori, T. ; Fujino, T. ; Yamamoto, S. ; Uzawa, S. ; Kimata, M.
Author_Institution :
Mitsubishi Electr. Corp., Itami, Japan
Abstract :
We have fabricated experimental memory cell arrays with a unit cell size of 0.29 μm2 (0.38 μm×0.76 μm). The layout was designed for a half-pitch 8F2 cell with 0.14-μm process technology, which is promising for 1-gigabit DRAMs and beyond. We developed three advanced technologies for this fabrication. Firstly, synchrotron radiation (SR) X-ray lithography was used to replicate ultra-fine patterns instead of optical lithography. Secondly, we introduced a simple stacked capacitor composed of a metal-organic chemical vapor deposition (MOCVD) grown (Ba,Sr)TiO3 (BST) high-dielectric-constant film sandwiched by Ru-metal electrodes. Thirdly, we developed advanced etching techniques for the fine pattern fabrication using improved ECR discharged plasmas, which give less microloading effects
Keywords :
DRAM chips; ULSI; X-ray lithography; barium compounds; capacitors; chemical vapour deposition; permittivity; ruthenium; sputter etching; strontium compounds; synchrotron radiation; 0.14 micron; 0.38 micron; 0.76 micron; 1 Gbit; ECR discharged plasmas; MOCVD; Ru-(BaSr)TiO3-Ru; X-ray lithography; dielectric-constant; etching techniques; giga-bit scale DRAM cell; microloading effects; stacked capacitors; synchrotron radiation; ultra-fine patterns; unit cell size; Capacitors; Chemical technology; Chemical vapor deposition; MOCVD; Optical device fabrication; Optical films; Random access memory; Strontium; Synchrotron radiation; X-ray lithography;
Conference_Titel :
Electron Devices Meeting, 1995. IEDM '95., International
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-2700-4
DOI :
10.1109/IEDM.1995.499362
