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G. A. M. Reynolds, R. H. French, P. F.
Carcia, C. C. Torardi, G. Hughes‡, D. J. Jones, M. F. Lemon, M.
Reilly, L. Wilson, C. R. Miao "TiSi-nitride attenuating phase-shift
photomask for 193 nm lithography", 18th Annual BACUS Symposium on
Photomask Technology and Management, SPIE Vol. 3546, Edited
by B. J. Grenon, F. E. Abboud, 514-23,
(1998).
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P. F. Carcia, R. H. French, M. H. Reilly, M. F. Lemon, D. J. Jones,
“Optical Superlattices --- A Strategy for Designing Phase-shift Masks for
Photolithography at 248 nm and 193 nm: Application to AlN/CrN”, Applied
Physics Letters, 70, 2371-3
(1997)
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F. D. Kalk, R. H. French, H. U. Alpay, G. Hughes, "Attenuated Phase
Shifting Photomasks Fabricated from Cr-Based Embedded Shifter Blanks", Photomask
and X-Ray Mask Technology, SPIE Vol.
2254, edited by H. Yoshihara, 64-70 (1994).
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TiSi-nitride attenuating phase-shift photomask for 193 nm
lithography
Gillian A. M. Reynolds, R. H. French, P. F. Carcia, C. C.
Torardi, Greg Hughes‡, D. J. Jones, M. F. Lemon, M. Reilly, L.
Wilson, C. R. Miao
DuPont Central Research & Development, Wilmington, DE
19880-0356
‡DuPont Photomasks, Inc., Round Rock, TX 78664
ABSTRACT
We have developed a new attenuating embedded phase-shift mask
blank for 193 nm lithography based on novel TiSi-nitride chemistry. At 193 nm,
these materials offer high optical transmission, they are radiation damage
resistant, stable in common chemicals used to strip photoresist, process
compatible with use of a hard Cr etch mask, and exhibit excellent dry etch
selectivity to quartz. Specifically, optical transmissions of greater than 10%
were achieved in films with 1800 phase-shift. Irradiation at 6 mJ/cm2/pulse,
or ~60x the energy densities in commercial steppers, caused negligible change in
optical transmission for doses up to 2 kJ/cm2. Dry etching in an ICP
reactor with CF4+He or CHF3+O2 all gave greater
than 6:1 etch selectivity to quartz, for optimized conditions. Further, the
novel wavelength-tunable structure of these TiSi-nitride films permits equally
attractive phase-shift designs at 248 nm and longer wavelengths. Currently,
printing performance is under evaluation, and these properties will also be
reported.
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P. F. Carcia, R. H.
French, K. Sharp, J. S. Meth, B. W. Smith, "Materials Screening for
Attenuating Embedded Phase-Shift Photoblanks for DUV and 193 nm
Photolithography", 16th Annual BACUS Symposium on Photomask
Technology and Management, SPIE Vol. 2884, Edited by G. V. Shelden, J. A. Reynolds, 255-63, (1996).
Download a PDF Here
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Materials screening for attenuating embedded phase-shift
photoblanks for DUV and 193 nm photolithography
P. F. Carcia, R. H. French, K. Sharp, J. S. Meth, B. W. Smith#
DuPont Co. Central Research, Experimental Station, Wilmington,
DE 19880-0356
#Rochester Institute of Technology,
Microelectronic Engineering, Rochester, NY 14623-0887
ABSTRACT
We surveyed more than 150 different materials as candidates
for optically tunable (at 248 nm and 193 nm), attenuating embedded phase-shift
masks. Multicomponent materials with four distinct microstructures: (1)
composites, (2) cermets, (3) multilayers, and (4) copolymers, where one
component was optically clear at the application wavelength and the other
component more optically absorbing, provided a systematic approach for adjusting
the needed optical properties: specifically, optical transmission and p-phase-shift.
From evaluation of optical properties and other mask manufacturability issues,
including chemical and radiation durability, etch selectivity, alignment and
inspection properties, film stress and adhesion, we identified promising nitride
and oxide materials based on MNx-AlN (M=Cr, Mo, W,...) and M'Oy-RuO2 (M'=Al, Hf, Zr...) as well as promising polymers.
F. D. Kalk, R. H. French, H. U. Alpay, G. Hughes, "Attenuated Phase Shifting Photomasks Fabricated from Cr-Based Embedded Shifter Blanks", Photomask and X-Ray Mask Technology, SPIE Vol. 2254, 64-70, (1994).
I-line (365 nm) and G-line (436 nm) attenuated phase shifting photomasks have been developed using single layer Cr-based photoblanks. The absorber layer has a composition gradient that allows the desired transmission to be tuned while maintaining control over reflectivity and phase shift. These photoblanks are manufactured in existing facilities, and masks are processed much like conventional opaque Cr-based materials. They can be inspected and repaired on current equipment with slight modifications. Printing has been demonstrated on current generation steppers. Deep UV extendability of these materials is also being studied, with a 5% Deep UV (248 nm) single layer photoblank chemistry already demonstrated.
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