Effects of Megasonic Power in Diw Rinsing on Particle Removal Efficiency and Defect Density
Effects of megasonic power in DIW rinsing on particle removal efficiency and defect density
Abstract- As the IC fabrication feature size gets smaller, the particle removal process becomes a critical step. It was proven that megasonic in SC-1 chemical is effective in removing surface contaminants but might inflicting structure damage [1-2] especially for geometry smaller than 130nm technology. Since Moore’s law states that the number of transistor on an IC chip will be double every two years, the problem will only get larger [3]. Therefore, it is important to optimize the current RCA cleaning step in order to improve the particle removal efficiency and at the same time preventing pattern damage. Effects of megasonic power in both SC-1 and DIW in term of particle removal efficiency and defect density will be studied. Experimental result for different megasonic power using blanket and pattern wafers will be presented. Results indicate that additional megasonic cleaning in DIW after SC-1 chemistry drastically improves particle removal efficiency, and with the use of appropriate megasonic power in both SC-1 and DIW, it is possible to maintain the particle removal efficiency and simultaneously, cause no pattern damage.
I. Introduction
Particulate surface contamination is a major cause of yield loss in semiconductor [4]. Particles easily introduced by chemistry during processing. SC-1 chemical used in RCA clean is already contaminated with particles of submicron size. Chemicals of the grade need in ULSI processing were tested for particulate by Frederick W. Kern and found that ammonium hydroxide has the highest particle count as compared to other chemistry such as hydrochloric [5]. In addition, the same chemical is used repetitively for several batches and this can become the source of contamination since the residue of organic will build up in the fluid and might re-deposit back on other surface [6]. It is impossible for a foundry to change the
Abstract- As the IC fabrication feature size gets smaller, the particle removal process becomes a critical step. It was proven that megasonic in SC-1 chemical is effective in removing surface contaminants but might inflicting structure damage [1-2] especially for geometry smaller than 130nm technology. Since Moore’s law states that the number of transistor on an IC chip will be double every two years, the problem will only get larger [3]. Therefore, it is important to optimize the current RCA cleaning step in order to improve the particle removal efficiency and at the same time preventing pattern damage. Effects of megasonic power in both SC-1 and DIW in term of particle removal efficiency and defect density will be studied. Experimental result for different megasonic power using blanket and pattern wafers will be presented. Results indicate that additional megasonic cleaning in DIW after SC-1 chemistry drastically improves particle removal efficiency, and with the use of appropriate megasonic power in both SC-1 and DIW, it is possible to maintain the particle removal efficiency and simultaneously, cause no pattern damage.
I. Introduction
Particulate surface contamination is a major cause of yield loss in semiconductor [4]. Particles easily introduced by chemistry during processing. SC-1 chemical used in RCA clean is already contaminated with particles of submicron size. Chemicals of the grade need in ULSI processing were tested for particulate by Frederick W. Kern and found that ammonium hydroxide has the highest particle count as compared to other chemistry such as hydrochloric [5]. In addition, the same chemical is used repetitively for several batches and this can become the source of contamination since the residue of organic will build up in the fluid and might re-deposit back on other surface [6]. It is impossible for a foundry to change the
References: [1] W. Kern and D. Puitonen (1970), RCA Rev., vol. 31, 187 (1970) [2] Mayer and Schwartzman (1979), Electronic Materials, vol.8, 855 (1979) [3] R. Schaller (1997), "Moore 's Law: Past, Present, and Future," IEEE Spectrum, June 1997, pp. 52–59. [4] Ahmed A.Busnaina and Glenn W.Gale (1995), “Ultrasonic and Megasonic Review”, Precision Cleaning Proceedings (1995) [5] Mitsushi Itano, Ichiro Kawanabe, FredrickW [6] Michael H. Jones, Stephen H. Jones, “Wet-chemical etching and cleaning of silicon” Virginia semiconductor Inc.(2003) [7] Kern W [10] Mark J. Beck (2005), “Megasonic cleaning charts a course to the big time”, Precision Cleaning (2005) APPENDIX