Polishing pad conditioning is essential for achieving stable chemical mechanical polishing (CMP). While diamond disk conditioners (DDCs) are often applied, flexible fiber conditioners (FFCs) have been proposed as a new conditioning tool. FFCs are intended for roughening the pad surface appropriately by bundling fine wire fibers. Our previous study demonstrated the fine conditioning characteristics of FFCs for a hard urethane foam pad. In this study, the conditioning characteristics of an FFC are compared with those of a DDC. First, we evaluate the conditioning performance of an FFC using SUS fibers on a soft urethane foam pad. The result indicates that on a soft pad, the SUS-FFC can restore the pad surface asperities more finely, as confirmed via the stabilized number of contact points based on contact image and luminance value distribution analyses. Subsequently, for a metal-contamination-free FFC process intended for semiconductor CMP, we develop an FFC fabricated using polyether ether ketone (PEEK) and verify its performance via the CMP test of a silicon oxide film. It is shown that the hard pad can be conditioned using the developed PEEK-FFC; this implies that a stable removal rate can be realized immediately after pad break-in conditioning.

1. [1] W. Izumiya, “A thorough report on investment plans for the semiconductor industry, which is entering an unprecedented boom – A huge market of 100 trillion yen approaching in the 5G revolution – (in Japanese),” Proc. of 187th Meeting of Planarization CMP Committee, pp. 41-54, 2021.
2. [2] S. Kurokawa, “The overview and future prospects for planarization CMP technology,” J. of the Japan Society for Precision Engineering, Vol.84, No.3, pp. 213-216, 2018.
3. [3] N. B. Kenchappa, R. Popuri, A. Chockkalingam, P. Jawali, S. Jayanath, D. Redfield, and R. Bajaj, “Soft chemical mechanical polishing pad for oxide CMP applications,” ECS J. of Solid State Science and Technology, Vol.10, 014008, 2021.
4. [4] G. B. Basim and B. M. Moudgil, “Slurry design for chemical mechanical polishing,” KONA Powder and Particle J., Vol.21, pp. 178-184, 2003.
5. [5] M. Uneda, “Polishing mechanism analysis based on visualizing of consumables effect,” J. of the Japan Society for Precision Engineering, Vol.84, No.3, pp. 225-229, 2018.
6. [6] R. K. Singh, A. Galpin, and C. Vroman, “Development and performance data of a new CVD diamond CMP pad conditioner,” Application Note, Entegris, pp. 1-5, 2013.
7. [7] C. Shin, H. Qin, S. Hong, S. Jeon, A. Kulkarni, and T. Kim, “Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process,” J. of Mechanical Science and Technology, Vol.30, No.12, pp. 5659-5665, 2016.
8. [8] S. Kim, N. Saka, and J. H. Chun, “The Effect of pad-asperity curvature on material removal rate in chemical-mechanical polishing,” Procedia CIRP, Vol.14, pp. 42-47, 2014.
9. [9] L. J. Borucki, T. Witelski, C. Please, P. R. Kramer, and D. Schwendeman, “A theory of pad conditioning for chemical-mechanical polishing,” J. of Engineering Mathematics, Vol.50, pp. 1-24, 2004.
10. [10] N. Suzuki and Y. Hashimoto, “Development of accurate prediction technology of material removal rates distribution in planarization CMP,” J. of the Japan Society for Precision Engineering, Vol.84, No.3, pp. 221-224, 2018.
11. [11] B. Park, S. Jeong, H. Lee, H. Kim, H. Jeong, and D. A. Dornfeld, “Experimental investigation of material removal characteristics in silicon chemical mechanical polishing,” Japanese J. of Applied Physics, Vol.48, 116505, 2009.
12. [12] T. Fujita, T. Doi, D. Kamikawa, and J. Watanabe, “Development on pad conditioning conforming to pad surface – Development of flexible fiber conditioner and evaluation on conditioning uniformity –,” J. of the Japan Society for Precision Engineering, Vol.76, No.4, pp. 433-437, 2010.
13. [13] M. Uneda, N. Takahashi, Y. Arai, and T. Fujita, “Effectiveness of novel pad dressing method by flexible fiber dresser,” J. of the Japan Society for Abrasive Technology, Vol.59, No.8, pp. 459-464, 2015.
14. [14] M. Uneda, Y. Maeda, K. Ishikawa, K. Ichikawa, T. Doi, T. Yamazaki, and H. Aida, “Relationships between contact image analysis results for pad surface texture and removal rate in CMP,” J. of The Electrochemical Society, Vol.159, No.2, pp. H90-H95, 2012.
15. [15] T. Akagami and M. Kawabata, “Effects of counterface surface roughness on friction and wear of PEEK materials under oil-lubricated conditions,” Tribology, Vol.11, No.3, pp. 494-502, 2016.
16. [16] S. Najeeb, M. S. Zafar, Z. Khurshid, and F. Siddiqui, “Applications of polyetheretherketone (PEEK) in oral implantology and prosthodontics,” J. of Prosthodontic Research, Vol.60, pp. 12-19, 2016.
17. [17] X. Ling, X. Jing, C. Zhang, and S. Chen, “Polyether Ether Ketone (PEEK) properties and its application status,” IOP Conf. Series: Earth and Environmental Science, Vol.453, 012080, 2020.
18. [18] JIS G4304 (Hot-rolled stainless steel plate, sheet and strip).
19. [19] VICTREX PEEK Coating Technology: VICOTE High Temperature Performance Coating.
20. [20] Nitta DuPont Incorporated: IC1000.
21. [21] J. McAllister, C. Stuffle, Y. Sampurno, D. Hetherington, J. S. Suarez, L. Borucki, and A. Philipossian, “Effect of conditioner type and downforce, and pad surface micro-texture on SiO₂ chemical mechanical planarization performance,” Microelectronics, Vol.10, No.258, pp. 1-8, 2019.