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Proceedings Paper

Embedded attenuating phase-shift mask: printability of defects
Author(s): Rajeev R. Singh; Alvina M. Williams; Chi-Min Yuan; Greg P. Hughes; G. Foss; Ronald M. Martino
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Paper Abstract

The manufacture of an embedded attenuating phase shift mask (E-APSM) is the simplest among all the phase shift mask (PSM) types. This is because an E-APSM provides the necessary attenuation and phase shift requirements using a single layer absorber film. Therefore, the tasks of patterning, inspection and repair are much easier to accomplish than for a multi-level quartz etched or SOG/SiO2 coated PSM. Reports in literature indicate that an E-APSM, also referred to as a single-layer half-tone PSM, is likely to be used for the contact masking layer in the manufacture of 64 M-bit DRAMs. It has also been stated that defect-free E-APSMs will be manufactured using currently available mask making tools. Therefore, it could be inferred that the defect specifications for an E-APSM are expected to be the same as that for a standard chrome mask. Perturbation modeling studies indicate that this should be true. An experimental study of repair and printability of defects on contacts on an E- APSM, using a chrome-based embedded attenuating film was performed. Exposures were made on an i-line stepper with NA equals 0.6 and sigma equals 0.6. Oxide wafers were coated with a high contrast i-line resist and the contact pattern was transferred into the oxide using a decorative etch process. Measurements were made using a SEM. The wafer results were also compared with printability studies done using an aerial imaging measurement system. The results of repairs done on 1 micrometer size defects on 2 micrometer size contacts indicate that the currently available laser repair tool was successful in restoring the lithographic performance of the E-APSM contacts to an acceptable level.

Paper Details

Date Published: 8 December 1995
PDF: 18 pages
Proc. SPIE 2621, 15th Annual BACUS Symposium on Photomask Technology and Management, (8 December 1995); doi: 10.1117/12.228181
Show Author Affiliations
Rajeev R. Singh, Intel Corp. (United States)
Alvina M. Williams, SEMATECH (United States)
Chi-Min Yuan, Motorola Inc. (United States)
Greg P. Hughes, DuPont Photomask, Inc. (United States)
G. Foss, DuPont Photomask, Inc. (United States)
Ronald M. Martino, IBM Microelectronics (United States)

Published in SPIE Proceedings Vol. 2621:
15th Annual BACUS Symposium on Photomask Technology and Management
Gilbert V. Shelden; James N. Wiley, Editor(s)

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