CeO_(2)로 코팅된 CMP용 SiO_(2) 나노 粒子 製造
Preparation of SiO₂nano-particle coated with CeO₂for CMP Slurry
코팅입자 CMP 나노입자;
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It is needed to accumulate circuit using multi-layer interconnection structure to enhance the performance of semiconductor device. To make this multilayer interconnection structure, base-layer surface flattening process is essential. Thermal flow, sputtering, photoresist etching etc. have been developed and used in process from late 1980s to solve these problems. However, mechanical polishing makes the defect of semiconductor chip, because of the degeneration of the layer after processing. Chemical polishing method also have a defect. It can't make surface which has desired shape accuracy. To overcome these problems, IBM developed chemical mechanical polishing(CMP) process, newly. The CMP process combines the chemical polishing and the physical polishing into one process. It is reported that the CMP process has hundreds times higher planarization dimension than other individuation polishing methods such as the mechanical polishing method and the chemical polishing method. At the CMP process the slurry of metallic oxide particles is used to polish the semiconductor surface. This slurry is consisted of DI water, particle, stabilizer, surfactant etc. The particle is the most important thing to achieve high polishing efficiency. SiO_(2) or CeO_(2) is used as the particle, usually. Among those, CeO_(2) is studied much recently, because it can produce high selectivity with less particle density in the selective CMP process. However, CeO_(2) has difficulty in the process, because its first particle has angled crystal structure. This research is going to progress as follows. To solve the problem of the CeO_(2) particle, the CeO_(2) particle is coated over on the SiO_(2) particle after making it as the basis particle. In this case, there are some advantages, the fine polishing efficiency of CeO_(2) particle can be acquired and the good dispersion and the form of SiO_(2) particle can be kept, simultaneously. The Method of coating the CeO_(2) particle on the SiO_(2) particle is as follows. After the SiO_(2) particle is grown first in solution through the sol-gel method, the precursor for CeO_(2) is added to the solution and the coated CeO_(2) precursor is oxidized. By these methods, the CMP particle of dual structure is made.