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Proceedings Paper

FIB repair of opaque defects for 64-Mb-DRAM-level binary masks
Author(s): Kyung Hee Lee; Hanku Cho; Jin-Hong Park; Yonghoon Kim; Hee-Sun Yoon; Jung-Min Sohn
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Paper Abstract

For binary masks, focused ion beam (FIB) repair of opaque defects is of importance to improve mask yield and turn- around-time with the increasing packing density and continuing shrinkage of feature sizes. The effectiveness of the FIB mask repair is mainly limited by riverbedding, glass overetching, gallium staining, knock-on chrome, and image shift due to charging effect. These effects exert more influence on contact patterns than line and space patterns in the case of the same size of opaque defects under given design rule. In this paper, we investigate FIB repair of test masks which have background contact patterns with a variety of programmed opaque defects including unopened contact for feasible application of 64 M DRAM level. The geometry of the background contact pattern is designed for an approximate target critical dimension (CD), 0.41 micrometers whose feature size is a rough limit of the contact CD with reasonable depth-of-focus (DOF) and exposure time (ET) margin for binary masks when printed on a wafer with a 5X reduction i-line (365 nm) stepper. After repair with an optimum dose, a series of procedures for confirming its success is presented, that is, detectability, aerial image measurement software results, and wafer printability results. In addition, atomic force microscope results and 3D optical lithography simulation are presented for comparison. In our experiment and simulation results, (Delta) ET equals 100 msec and DOF equals 0.6 micrometers are obtained for the repaired contact.

Paper Details

Date Published: 27 December 1996
PDF: 12 pages
Proc. SPIE 2884, 16th Annual BACUS Symposium on Photomask Technology and Management, (27 December 1996); doi: 10.1117/12.262830
Show Author Affiliations
Kyung Hee Lee, Samsung Electronics Co. Ltd. (South Korea)
Hanku Cho, Samsung Electronics Co. Ltd. (South Korea)
Jin-Hong Park, Samsung Electronics Co. Ltd. (South Korea)
Yonghoon Kim, Samsung Electronics Co. Ltd. (South Korea)
Hee-Sun Yoon, Samsung Electronics Co. Ltd. (South Korea)
Jung-Min Sohn, Samsung Electronics Co. Ltd. (South Korea)

Published in SPIE Proceedings Vol. 2884:
16th Annual BACUS Symposium on Photomask Technology and Management
Gilbert V. Shelden; James A. Reynolds, Editor(s)

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