Single Wafer Selective Silicon Nitride Removal with Phosphoric Acid and Steam

Abstract:

A single wafer silicon nitride (SiN) selective etch process with an etch rate greater than 80A/min of low-pressure chemical vapor deposited (LPCVD) SiN has been developed. Previous work with a similar single wafer system utilized a mixture of sulfuric acid, phosphoric acid and steam to achieve a high SiN etch rate [1]. The process in this work relies on phosphoric acid and steam for a high SiN etch rate. In both of these applications, addition of steam doubles the SiN etch rate. The single wafer system utilizes a closed chamber design with integrated spray bar to uniformly dispense hot phosphoric acid and steam onto the wafer surface achieving within wafer non-uniformities of less than 3%. Rinsing and drying of the phosphoric acid from the wafer surface occurs in the same chamber (dry in/dry out) providing a stable, haze free wafer. Figure 1 contains a schematic of the phosphoric acid delivery and single wafer system.

• Periodical: Solid State Phenomena (Volume 219)
• Pages: 97-100
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.219.97
• Online since: September 2014
• Authors: Ted Guo*, Wesley Yu, C.C. Chien, Euing Lin, N.H. Yang, J.F. Lin, J.Y. Wu, Anthony Ratkovich, Don Kahaian, Jeffery W. Butterbaugh, Jeffrey M. Lauerhaas
• Keywords: Reclaim, Selectivity, Silicon Nitride, Single Wafer, Steam

References

[1] B. Yu, et al.: Solid State Phenomena, 195(2013), p.46.

[2] W. van Gelder and V.E. Hauser: J. Electrochem. Soc. 114(8) (1967), p.869.

[3] S.J. Buffat, M.S. Lucey, M.R. Yalamanchili and C.S. Hatcher: Semiconductor International, 25(9) (2002), p.57.

[4] Y.C. Liu et al.: IEDM Technical Digest (2005), p.836.