| 학회 | 한국재료학회 |
| 학술대회 | 2006년 봄 (05/19 ~ 05/20, 경상대학교 ) |
| 권호 | 12권 1호 |
| 발표분야 | 반도체재료 |
| 제목 | Effects of Amorphous-silicon and Poly-silicon films on Within-Wafer Non-Uniformity (WIWNU) Improvement in Chemical Mechanical Polishing. |
| 초록 | As device dimensions continue to decrease and the leading-edge feature size becomes smaller than 0.7 um, the chemical mechanical polishing (CMP) process must be capable of removing a very thin layer of poly-silicon and oxide films with flat surface to form the floating gate in NAND-flash memory application. In addition, CMP technique has been considered to improve the surface uniformity of the poly-silicon film to increase its carrier mobility. The dielectric films whether deposited or thermally grown on such polished poly-silicon present excellent breakdown properties and much lower junction leakage. However, in contrast to its popular applications of CMP, the mechanisms to improve the surface uniformity of poly-silicon films, especially for the poly-silicon involved in the chemical reaction between slurry and film surface during CMP process, are unknown in detail. In this study, therefore, we investigated the effects of the amorphous-silicon and poly-silicon films on surface uniformity improvement by performing CMP process. The amorphous-silicon film was deposited on the oxidized substrate in an LPCVD system at 530 oC. The poly-silicon film was deposited by rapid thermal annealing (RTA) treatment for 15sec at 930 oC after amorphous-silicon film formation. The films were polished with a Strasbaugh 6DS-SP. The films thickness variation of the blanket wafer before and after CMP was measured with Nano-spec 180 (Nanometrics) and Ellipsometer (Ellipso technology). The depth of line profile in remaining films was measured by SEM (Hitachi) and AFM (PSIA). We found that not only improved the film surface uniformity and optimized process condition during CMP process. For the amorphous-silicon film, film surface uniformity after CMP is better than the poly-silicon film at a same experimental condition will result in higher surface planarity for commercial slurry. In optimized CMP process condition, the rotation speeds of both the head and the table were 30 (low) rpm, and the directly head pressure was 3 (low) psi. The slurry flow rate was 100 cm3/min and the polishing time was 30 s. *The Korea Ministry of Science and Technology supported this work through the National Research Laboratory (NRL) program. We thank SUMCO Corp. and Hynix Semiconductor, Inc. for helping us with our experiments. |
| 저자 | Yoon-Kweon Choi1, Jae-Il Choi2, Kyung-Woong PARK1, Ungyu PAIK2, Jea-Gun PARK1 |
| 소속 | 1Nano SOI Process Laboratory, 2Hanyang Univ. |
| 키워드 | WIWNU; CMP; slurry; Poly-silicon films; Amorphous silicon films |
