Research on High Quality Single Wafer Wet Processing for Semiconductor Surfaces
木下, 圭KINOSHITA, Kei
562015-03-24 , 法政大学大学院理工学・工学研究科
To obtain uniform surfaces from etching and cleaning, we focus herein on single-wafer-spinning wet-processing (SWSWP). This thesis presents research that we have conducted on new techniques of SWSWP that can be applied to various materials. We explained that, by removing defect layers introduced by the back-grinding process of SWSWP, the minority-carrier lifetime can be greatly improved, which significantly impacts the electrical characteristics of the resulting semiconductor. We clarified that planarization by chemical-mechanical polishing yields a more uniform thickness after film deposition, independent of the deposition distribution of the film resulting from SWSWP. Discussed research into the mechanism of removal and reattachment of fine nitride particles by cleaning with an ammonia peroxide mixture and clarified the importance of control and reattachment of fine particles. Furthermore, we clarified that reattachment of fine particles can be suppressed by controlling the medium-boundary-layer thickness. The development of a new ultrasonic cleaning technology that avoids pattern collapse was described. We showed that fine (65 nm) nitride particles can be efficiency removed without the collapse of fine patterns using a newly developed ultrasonic cleaning technique. We considered the use of a chemical solution to remove particles and propose a new electrochemical cleaning method based on this mechanism. This method combines low ultrasonic cleaning, a diluted ammonia peroxide mixture, and strong alkaline ionized water at pH 12. The result is free of film loss and pattern collapse. We proposed a cleaning method environmentally friendly and economic that uses only deionized water (DIW). PSL particles were removed by DIW after conditions were optimized. A novel cleaning method that efficiently removes any Pt that has contaminated the wafer backside and bevel was described. The method uses hydrochloric and nitric acid to generate aqua regia directly on the wafer. We clarified how to efficiently remove metals, such as Pt, with low ionization energy. How pretreatment with SWSWP of a copper-film-deposition process affects the copper damascene interconnect technology was described. With this approach, we reduced the resistivity of the resulting thin copper film that forms the high-aspect-ratio contact. How ideal shape control with high adherence and low contact resistance can be realized by pretreating the copper surface by SWSWP before deposition of CoWP as a cap layer, which is deposited by electroless plating was described. We proposed a new drying technology that dispenses with water marks by using isopropyl alcohol. This approach proved to be a better drying technology for hydrophobic surfaces without water mark is generated. Finally, we proposed a new single-wafer spin technology that combines dry and wet processing. The photoresist with crust layer into which a high dose of ions are implanted at high energy can be quickly removed by a continuous process that combines an atmospheric inductively coupled plasma and SWSWP with SPM.