The Impact of Backside Particles on the Limits of Optical Lithography

Abstract:

• Periodical: Solid State Phenomena (Volumes 103-104)
• Pages: 129-132
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.103-104.129
• Online since: April 2005
• Authors: Twan Bearda, Paul W. Mertens, Frank Holsteyns, Peter De Bisschop, René Compen, Aschwin van Meer, Marc Heyns
• Keywords: Backside Particles, Contamination, Lithography, Nanotopography

References

[1] P. S. Lysaght, Adv. Semic. Manuf. Conf. 1999 pages 388-393.

[2] L. A. Cheema, Adv. Semic. Manuf. Conf. 2002 pages 64-71.

[3] International Technology Roadmap for Semiconductors, version 2003, table 69. http://public.itrs.net.

[4] W. Class and M. Jackson, Solid State Technology 46 (January 2004) pages 34-44.

[5] S. P. Timoshenko and S. Woinowsky-Krieger, 'Theory of plates and shells', McGraw-Hill 1989, page 51.

[6] S. P. Timoshenko, 'Theory of Elasticity', McGraw-Hill 1970, page 403.

[7] C. T. Lynch, "CRC handbook of materials science. 3: Nonmetallic materials and applications." Boca Raton, Florida: CRC Press, 1986, pages 14, 21-22, 53 and 60.

[8] www.matweb.com, 16 December, 2003. 10-3 100 103 10-3 10 0 10 3 max. wafer deflection (µm) particle radius (µm)R maxw σy, part = 1 GPa 0.1 GPa 0.01 GPa ITRS spec 2004 2009 -10 5 Pa∆q= Table I: compressive yield strengths and moduli of elasticity of some commonly used materials [7,8]. material compressive strength (MPa) diamond 8680-16530 Si 2800-6800 alumina 1500-3800 SiC 2000-4500 quartz 300-1100 stainless steel 300-1200 copper 300-900 aluminum 100-400 epoxy 140-550 polystyrene 70-140 polycarbonate 86 polypropylene 34-48 concrete 40 Figure 7: wmax as a function of backside particle radius R, taking into account elastic indentation and plastic particle deformation. For clarity, the case of plastic wafer deformation is omitted; however that curve does not differ much from the shown curves. 0 20 40 60 80 100 120 140 160 180 200 -0.1 -0.05 0 0.05 0.1 -0.1 -0.05 0 0.05 0.1 I2, background-Z G W 0 20 40 60 80 100 120 140 160 180 200 -0.1 -0.05 0 0.05 0.1 -0.1 -0.05 0 0.05 0.1 I2, background-Z G W Figure 8: lightscatter map of the backside of a 300mm wafer, measured on an SP1TBi. The particles are 1.2µm silica spheres. The rings were caused by previous processing. The map is mirrored to reflect the particle position when the wafer frontside faces up. Figure 9: Twinscan wafermap of wafer contaminated with 1.2µm particles. The same wafer was measured again after cleaning the wafer and the wafertable. The difference in wafer topography remained below the detection limit of approx. 10nm. Figure 10: Average wafer flatness of 10 reference wafers. 200nm 0nm 200nm 0nm 10/cm2 100/cm2 500/cm2