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Proceedings Paper

Overlay and critical dimension control in 100-nm ULSI processes using TaBN x-ray masks and the XRA x-ray stepper
Author(s): Kiyoshi Fujii; Yuusuke Tanaka; Toshiyuki Iwamoto; Shinji Tsuboi; Hiroaki Sumitani; Takao Taguchi; Katsumi Suzuki; Yasuji Matsui
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Paper Abstract

We developed highly precise x-ray masks and used them to fabricate 100-nm-rule gate and contact-hole (C/H) level masks for 4-Gb DRAM test processes. The masks consisted of 350-nm-thick TaBN absorbers, 3-micrometers -thick SiC membranes, 1- mm-thick Si substrates and 6.63-mm-thick Pyrex glass frames. The membranes and absorbers were deposited in facilities at Hoya Corporation. The frames were bonded to the Si substrates using anodic bonding resulting in a convex surface. An EB-X3 high-precision 100-kV electron-beam writer was used to delineate the patterns. The image placement (IP) accuracy was within +/- 15 nm in both the gate- and C/H-level masks. The critical dimension (CD) variations for 100 nm features measured in a 24 mm square chip area were within +/- 6 nm in the best case. The x-ray masks were used for overlay and CD control evaluating of he XRA mass production x-ray stepper developed by Canon, Inc. The overlay evaluation was done using a double exposure method. The C/H layer was exposed aligning to the gate marks by using the advanced dual grating lens (ADGL) method in global-alignment mode. The total overlay accuracy between the gate and C/H levels was better than +/- 30 nm, including the intra-chip IP errors caused by mask distortion. The overall CD variation for the resist patterns was within +/- 13.1 nm in the gate level and +/- 8.2 nm in the C/H level.

Paper Details

Date Published: 20 August 2001
PDF: 9 pages
Proc. SPIE 4343, Emerging Lithographic Technologies V, (20 August 2001); doi: 10.1117/12.436645
Show Author Affiliations
Kiyoshi Fujii, Association of Super-Advanced Electronics Technologies (Japan)
Yuusuke Tanaka, NEC Corp. (Japan)
Toshiyuki Iwamoto, NEC Corp. (Japan)
Shinji Tsuboi, Association of Super-Advanced Electronics Technologies (Japan)
Hiroaki Sumitani, Association of Super-Advanced Electronics Technologies (Japan)
Takao Taguchi, Association of Super-Advanced Electronics Technologies (Japan)
Katsumi Suzuki, NEC Corp. (Japan)
Yasuji Matsui, Association of Super-Advanced Electronics Technologies (Japan)

Published in SPIE Proceedings Vol. 4343:
Emerging Lithographic Technologies V
Elizabeth A. Dobisz, Editor(s)

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