Light-coupling masks for lensless, sub-wavelength optical lithography

Applied Physics Letters

Volumn 72, Issue 19, 1998, Pages 2379-2381

  Schmid, Heinz ^a   Biebuyck, Hans ^a   Michel, Bruno ^a   Martin, Olivier J F ^b  

^a IBM RESEARCH ZURICH   (Switzerland)

^b ETH ZURICH   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

AMPLIFICATION; CALCULATIONS; COMPUTER SIMULATION; ELECTRON BEAM LITHOGRAPHY; ORGANIC POLYMERS; PHOTOLITHOGRAPHY; PHOTORESISTS; REFRACTIVE INDEX; SEMICONDUCTOR DEVICE STRUCTURES; SUBSTRATES;

GREEN TENSOR TECHNIQUE; LIGHT COUPLING MASKS;

MASKS;

EID: 0032073945     PISSN: 00036951     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.121362     Document Type: Article

References (10)

1. E. Cullmann, Semicond. Int. 8, 332 (1985).
2. J. A. Rogers, K. E. Paul, R. J. Jackman, and G. M. Whitesides, Appl. Phys. Lett. 70, 2658 (1997).
3. Not all types of structures can be successfully replicated in elastomeric materials, however [E. Delamarche, H. Schmid, B. Michel, and H. Biebuyck, Adv. Mater. 9, 741 (1997)].
4. We depended on the formulation of high-strength siloxanes (Young's modulus >3MPa) based on commercially available copolymers (ABCR, Karlsruhe, Germany) V731, HMS301, silane to vinyl terminated ratio 1:1.5. 5% fused silica filler (10-15 nm particle size) was added [B. Michel et al. (unpublished)]. The polymers were translucent down to 230 nm and absorbed 30% of the light at 248 nm for a 3-mm-thick LCM. We found that filled materials substantially more absorbing (97% of the light) at this wavelength nevertheless formed useful LCMs, underscoring the greatly relaxed optical-material requirements of LCMs compared to traditional (thick) optical elements.
5. Y. Xia, E. Kim, X.-M. Zhao, J. A. Rogers, M. Prentiss, and G. M. Whitesides, Science 273, 347 (1996).
6. D. M. Tennant, Microelectron. Eng. 27, 427 (1995).
7. Thermal evaporation placed a 50-Å-thick layer of gold on the entire surface of the stamp. Allowing this stamp to contact a gold substrate having a self-assembled monolayer (SAM) of 1,9 nonanedithiol [Aldrich] for 1 s effected the selective removal of the gold from the surface of the stamp where it contacted the SAM. Such layers were used when features in the mask larger than the vacuum wavelength were targetted (see text).
8. O. J. F. Martin, C. Girard, and A. Dereux, Phys. Rev. Lett. 74, 526 (1995).
9. O. J. F. Martin (unpublished results).
10. The exposing light had a vacuum wavelength of 248 nm in all of these simulations and a direction of propagation that was normal to the substrate and was circularly polarized in the plane. A mesh size of 10 nm was employed for the calculation. The resist was treated as having constant optical properties on exposure in these simulations. We assumed an index of 1.6 for the LCM and resist.