S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Theses (Master's Degree_화학생물공학부)
소자 분리 공정용 화학적 기계적 연마 슬러리 특성에서의 유기 첨가제 영향 연구
- Issue Date
- 서울대학교 대학원
- 학위논문(석사)--서울대학교 대학원 :응용화학부,2003.
- With the shrinkage of device design rule, global planarization
using c hemical mechanical polishing (CMP) becomes the most
important technology in ultra large scale integrated (ULSI)
device fabrication. The role of STI (Shallow Trench Isolation)
CMP removes silicon oxide on silicon nitride to make field oxide.
In STI CMP process, the use of slurry with low removal
selectivity results in change of field oxide thickness and
decrease of over-polishing margin. To overcome these
disadvantages, organic additives have been used to increase the
removal selectivity by changing surface potential of the wafer.
The effect of organic additives in slurry on STI CMP
performance has not been reported yet. The purposes of this
research were to measure surface potential of the wafer and
effects of organic additives on removal selectivity. In this study,
poly(acrylic acid) was investigated as an organic additive.
In this study, glutaric acid, acrylic acid, and poly(acrylic acid)
were investigated as the organic additives. Zeta potential was
measured by using electrophoretic light scattering technique,
and additive adsorption was monitored by FT-IR. Surface of
wafers was characterized by FESEM. The removal rate of wafer
was evaluated by using ellipsometry.
The zeta potential of the wafer was measured according to
pH in solution with or without additives. glutaric acid did not
change the zeta potential of silicon nitride surface. However,
when acrylic acid or poly(acrylic acid) was added, silicon nitride wafer showed the more negative zeta potential value. It was
believed that zeta potential of silicon nitride decreased due to
the adsorption of poly(acrylic acid) on wafer surface, which was
confirmed by FT-IR analysis. The zeta potential of the wafer
was measured by changing of poly(acrylic acid) concentrations...
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