| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 105 === Chemical mechanical polishing (CMP) is early applied in lens and wafers, it has been an important technology in of semiconductor manufacturing. It has been proved that stainless steel could be the substrate in solar cell and planarization of global substrate is contributed to battery conversion efficiency. According to the success of semiconductor, CMP in stainless steel will still be critical process manufacturing.
Planarization of stainless steel cannot be perfect if just polish it by mechanical or chemical force currently. By the way polishing slurries rely mainly on acidic in market. The acidic slurry cloud not provides better surface quality usually. In this study alkaline SiO2 slurry is investigate.
Effect of surface quality of each component in the slurry- pH, SiO2 concentration, oxidizer and surfactants will be analyzed. It is helpful to design slurry with better performance.
Experimental setting includes slurry components and parameter process. For slurry components:
1.Acidic slurry makes higher remove rate bur roughness worse , There are many nano-level pits, Besides abrasive in acidic slurry could not distributed very well subside. When the slurry was alkaline (pH10.0), remove rate could be kept and get better roughness. Abrasive distribute in the slurry very well steadily.
2.The results of SiO2 concentration test show that remove rate become higher with increasing SiO2 linearly. The reason is more abrasives contact surface per unit polishing time. But remove rate goes a plate as concentration more than 32 wt%
3.When citric acid the amount of defects formed by surface etching is minimized by using an appropriate amount of addition and can improvement the remove rate, so that the substrate surface with lower roughness.
4.The oxidizer mechanism is due to the rapid oxidation of the surface, citric acid can soften the surface of the stainless steel, formation of ferric iron and chromium ions and nickel ions and other soluble ionic, and appropriate of silica concentration, makes the effect of mechanical and chemical to balance.
For the polish parameters:
1.The relationship between remove rate, down force RPM of plate is fitting Preston equation.
2.Surface roughness is not so good with shorter longer polishing time. The optimal polishing time is helpful to make process period shorter.
3.More slurry flow rate cloud not increase remove rate because polishing region depends on substrate size. Optimal slurry flow rate cloud makes process steady and cost lower.
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